Polyester blends exhibiting low temperature toughness

[0001] The present invention relates to polymer blends that are particularly useful for shaping or forming into containers and similar articles shaped by thermoforming procedures. More specifically, the new polymer blends contain one or more thermoplastic polyester homopolymers or copolymers, an impact modifier and a nucleator to increase the crystallization rate of the polymer blend. Polymer blends exhibit improved impact strength, especially at low temperatures, and are suitable for food trays (containers) that can be exposed to low temperatures (cooling).

2. Background of the Invention [0002] Polyesters such as polyethylene terephthalate (PET) are engineering thermoplastics used for a wide variety of end uses, such as fibers, films, automotive parts, food and beverage containers and the like. PET can be processed by various techniques including injection molding, compression molding, extrusion, thermoforming, blow molding, and combinations thereof. Embossed in foil (also known as a sheet) with a thickness of 100 to 1000 microns, PET can be used as made or shaped, e.g. by thermoforming, in products such as displays, signs, credit or debit cards, or packaging products. For example, extruded PET film material can be used to produce trays, packaging or containers in which frozen food products can be both stored and heated and / or baked in an oven. As used herein, the terms tray or trays are intended to include packaging and containers in which food, especially frozen food, is packaged and sold for subsequent heating and / or cooking while it is still in the tray, packaging or container. Food packaging made of crystalline PET maintains good dimensional stability over the entire temperature range encountered during both microwave and convection oven cooking.

[0003] One of the problems encountered with PET food trays is that they sometimes break when trays containing frozen food are dropped. One way to improve the strength of trays at low temperatures, as measured by reducing the transition temperature from plastic to brittle, is to use high molecular weight PET when making the tray. Therefore, PET used in food trays is often made specifically for intrinsic viscosities (It.V.) from about 0.90 to about 1.05 dL / g. Another approach is to add impact modifier to PET during the film extrusion process. In general, trays are the most durable when both approaches are used.

[0004] Patent description Ser. Am. North 4,172,859 reveals that polymer materials that serve well as impact modifiers should (i) have a 1/10 modulus of elasticity from the polyester matrix material, (ii) be well dispersed in the matrix material with separate phases from 0.01 micron to 3.0 microns, and (iii) be well attached to the matrix.

[0005] Low modulus polymers commonly used as impact modifiers fall into several general classes. The first class contains rubbers based on butadiene or isoprene, e.g. polybutadiene, polyisoprene, natural rubber, styrene-butadiene (SBR), acrylonitrile-butadiene (ABN or nitrile rubber), styrene-butadiene-styrene (SBS) or hydrogenated SBS block copolymers (styrene-ethylene-butene-styrene) (SEBS) or acrylonitrile butadiene styrene (ABS), polymers containing high concentration of butadiene. Butadiene-based rubbers generally have low glass transition temperatures (T._g), which contribute to improving the strength at low temperatures, but cannot be stable at high temperatures at which polyesters are processed. The second major class of impact modifiers includes polyethylene based elastomers, e.g. ethylene propylene (EPR) or EPR with a small amount of diene group in the side chain (EPDM), ethylene acrylate copolymers such as ethylene / methyl acrylate copolymer, ethylene / ethyl acrylate copolymer, ethylene / butyl copolymer and ethylene methacrylate methacrylate copolymer glycidyl methacrylate or ethylene vinyl acetate copolymer (EVA). A third group of impact modifiers includes core-shell impact modifiers, such as those that contain a hard coating of poly (methyl methacrylate) (PMMA) or with a methacrylate-butadiene styrene (MBS) butadiene core (MBS) or butyl (acrylic) acrylate, e.g., PARALOID produced by Rohm & Haas Company. Core-shell impact modifiers based on acrylonitrile-butadiene-styrene (ABS) are also commercially available, e.g. BLENDEX manufactured by GE Specialty Chemicals). Other elastomers that can serve as impact modifiers include polyesters, e.g., HYTREL manufactured by EI duPont de Nemours Company and ECDEL produced by Eastman Chemical Company, and polyurethanes, e.g., PELLETHANE manufactured by Dow Chemical Company, or silicone rubbers.

[0006] By properly adjusting the melt viscosity of the matrix and impact modifier at melt mixing temperatures, excellent discrete impact modifier phases can be formed by shear forces obtained during melt processing. Screw mixing must be properly designed to create appropriate shear fields during the mixing / extrusion process. However, impact modifiers dispersed by purely mechanical action can re-combine at a later stage in the process in which shear can be reduced.

[0007] Alternatively, impact modifiers can be made to inherently small sizes using latex or other polymerization processes. Impact modifiers produced in this way often contain a rigid coating of harder polymer and are therefore often referred to as core-shell impact modifiers. These impact modifiers can be made in sizes 0.2 - 0.5 microns, ideally suited to modifying the impact strength of nylon, polycarbonate and polyesters. Still, these core-shell impact modifiers must also be dispersed by shear action during melt processing, and are susceptible to re-joining in later molding or mixing steps.

[0008] One way to increase the dispersion and prevent coalescence is to introduce functional groups into the impact modifier, which are either highly soluble in the matrix polymer or can react with the matrix polymer. Interaction between these functional groups and the matrix during mixing creates a thin intermediate layer of material that makes the impact modifier and matrix more energetically compatible. Compatibility regarding these functional groups leads to good mixing and good dispersion of the impact modifier. Increased compatibility will also reduce the possibility that the impact modifier phases will reconnect later during machining. Therefore, impact modifiers containing functional groups that react quickly with the polymer matrix produce well dispersed impact modifier phases with small particle size (See "Rubber Toughened Engineering Plastics", AA Collyer, Chapman & Hall, London, 1994). The introduction of functional groups into the impact modifier also ensures a good bond between the impact modifier and the matrix, i.e. the interphase adhesion between these immiscible phases.

[0009] Impact modifiers can be functionalized with various reactive or non-reactive monomers. These functional monomers can be introduced into impact modifiers directly during the preparation of the impact modifier or later by means of a graft polymerization step. Non-reactive impact modifiers (e.g., SAN grafted EPDM) are compatible with the matrix by better matching of the solubility parameters, without having to be combined with the matrix polymer. The reactive groups of reactive impact modifiers chemically bind to the matrix polymer, but to be effective, they must do so within the limited time available in the extruder during mixing (e.g., melt mixing).

[0010] Patent description Ser. Am. North 4,172,859 lists various functional groups that can be grafted or copolymerized on ethylene-based elastomers for use with polyesters and polyamides. In practice, maleic anhydride (MAH) by functionalizing impact modifiers works well with nylons, and there are many commercially available products, e.g. EPR-MAH, EVA-MAH and SEBS-MAH. However, the reaction between maleic anhydride and polyesters is not fast enough for significant compatibility in the time scales found under normal mixing. A functional group that reacts particularly well with polyesters is a monosubstituted oxirane or epoxy, such as in glycidyl methacrylate (GMA), glycidyl acrylate, allyl glycidyl ether and 3,4-epoxy-1-butene (EpB). This patent describes thermoplastic compositions containing blends of polyesters and random ethylene functionalized copolymers of epoxy.

[0011] The following patent documents describe polyester compositions that contain an epoxy-based ethylene polymer material (see also Scheirs, J., Additives for the Modification of Poly (Ethylene Terephthalate) to Produce Engineering-Grade Polymers in Modern Polyesters, Scheirs, J. and Long, TE (Eds), Wiley, New York, 2003, pp. 506-515)). Patent description Ser. Am. North. 4,172,859 describes thermoplastic compositions containing blends of polyesters and random epoxy functionalized copolymers of ethylene. This patent does not apply to catalyst residues present in polyesters. Patent description Ser. Am. North 4,284,540 describes the use of ethylene / GMA copolymers as a curing agent for polyesters in combination with 0.1 to 5 weight percent of added barium catalyst. This patent notes that PET containing antimony catalyst residues are beneficial for promoting reaction with olefin materials containing epoxy compounds. However, the patent did not provide any data that show any strength gain due to these catalyst residues. Patent description Ser. Am. North. 4,753,980 discloses that polyester compositions containing 3-40 percent by weight of either ethylene / ethyl acrylate / GMA terpolymer or ethylene / butyl acrylate / GMA terpolymer show better strength at low temperatures compared to analogous polyester compositions that contain ethylene / methyl acrylate terpolymer / GMA. The patent does not refer to catalyst residues. Patent description Ser. Am. North. 6,576,309 discloses a polymer composition comprising polyalkylene terephthalate, 4% by weight to 40% by weight ethylene / methyl acrylate copolymer, and 0.1% by weight to 8% by weight olefin / acrylate / GMA compatibilizing terpolymer, however the patent does not apply to present residues catalyst. Patent descriptions Ser. Am. North. 5,098,953, 5,086,119, 5,086,118, 5,086,116 and 5,068,283 disclose that the strength of a polyester composition containing ethylene / GMA copolymers or ethylene / alkyl acrylate / GMA terpolymers can be improved by adding a crosslinker to the composition. The crosslinking agent contains at least two functional groups reactive with an epoxy group, a carboxyl group or a hydroxyl group in one molecule.

[0012] St. Ser. Am. North 20060276587 discloses a core-shell impact modifier used in polymer formation (e.g., polyesters) to improve low temperature impact performance. In a preferred embodiment, the coating is a polymethyl methacrylate or a copolymer containing at least 85 percent by weight of methyl methacrylate. For the modification of polyesters, polyamide or the like, small amounts of reactive functionalities are typically incorporated into the composition in the coating step. Such reactive monomers may be glycidyl (meth) acrylate, (meth) acrylamide, (meth) acrylic acid, maleic anhydride and the like.

[0013] US Patent No. Ser. Am. North 5,206,291 describes compositions containing polyester containing 1,4-cyclohexanedimethanol and ethylene / GMA copolymer residues. Stewart et al., Polymer Engineering and Science, 33 (11), 675 (1993), discloses that PET containing antimony catalyst residues reacts faster with an ethylene / GMA copolymer than PET catalyzed by other metals. Patent description Ser. Am. North. 5,436,296 discloses that an ethylene / GMA copolymer can be used for the compatibility of a blend of polyethylene and polyester. European Patent Publication EP 481,471 131 and Penco et al. Journal of Applied Polymer Science, 57, 329 (1995) disclose compositions comprising polyester, low density linear polyethylene, ethylene / ethyl acrylate / GMA terpolymer and 0.5% to 1% amine to open the epoxy ring.

[0014] Patent descriptions of Ser. Am. North 5,483,001, 5,407,999 and 5,208,292 and Die Angewandte Makromolekulare Chemie, 1992, 196 p89, disclose improved strength polyester compositions that include ethylene / alkyl acrylate terpolymer / GMA, ethylene / alkyl acrylate terpolymer / maleic anhydride and a catalyst such as dimethyl stearylamine, which accelerates the reaction between the functional groups of two terpolymers. Patent description Ser. Am. North. 5,652,306 and European Patent Publication EP 737,715 A2 disclose polyester compositions containing MBS or acrylic core-shell impact modifiers in combination with a small amount of ethylene / alkyl acrylate / GMA terpolymer. Patent descriptions Ser. Am. North 7,015,261 and 7,119,152 disclose an improved impact modifier for thermoplastic polyesters. The impact modifier is a blend of (A) a core / shell impact modifier and (B) a linear copolymer derived from ethylene, (meth) acrylic esters and an epoxy-containing monomer.

[0015] While some of the previous patents discuss the use of a catalyst additive to promote the reaction between epoxy-containing polymers and polyesters, there is no disclosure in any of these patents that the strength of the blend is affected by the presence of catalyst residues used for making polyester. Polyesters are usually made using metal catalysts that remain in the polyester product. Examples of such catalysts include organic and inorganic compounds of arsenic, cobalt, tin, antimony, zinc, titanium, magnesium, gallium, germanium, sodium, lithium and the like. Titanium and antimony compounds are often used to make PET.

[0016] There is reference in U.S. Patent No. Ser. Am. North 4,284,540 and in Stewart et al. Poly. Eng. & Sci., 33 (11), 675 (1993) that certain catalyst residues present in PET can significantly affect the rate of reaction of epoxide functionalized polymers with PET. Patent description Ser. Am. North. 4,284,540 notes that of the above-mentioned polyester polymerization catalyst residues, antimony catalyst residues are preferred to promote the reaction between the polyester and the epoxy group. The patent, however, does not provide any data about the strength associated with the presence of these catalyst residues. Stewart et al.

quantified the reaction rate between PET and the ethylene copolymer and glycidyl methacrylate (E / GMA), monitoring the increase in torque of the mixture of these two components in an instrumented bowl (also known as torque rheometer). According to Stewart et al., Torque rheometry is a simple and direct method of monitoring the viscosity of polymer blends as a function of mixing time. The rheometer constantly measures the torque required for the rotation of the rotor blades, which shear and mix the sample in the bowl. For a given material and set of processing conditions, torque is measured by an approximately linear function of sample viscosity. Any changes in viscosity over time are in turn associated with effects such as changes in molecular weight in the sample (e.g., increase as a result of reaction or as a result of degradation) or the formation of strains, branches or bonds in the sample. The work of Stewart et al. Shows that mixtures of E / GMA with PET containing antimony catalyst residues lead to a significant increase in torque during mixing. This led to the conclusion that PET containing antimony catalyst residues accelerated the reaction between PET and E / GMA. It was noted that PET containing residual antimony catalyst causes a more rapid increase in torque than PET containing residual other catalysts. It is often implied by those skilled in the art that the rapid reaction between E / GMA and PET containing antimony catalyst residues should lead to better E / GMA (i.e. smaller particle size) scattering and better binding to PET. This better dispersion should in turn lead to increased strength in the resulting mixture. In addition, since PET containing antimony catalyst residues reacts faster than PET containing other catalysts, it is assumed that the use of PET containing antimony catalyst residues should lead to harder blends with ethylene copolymers containing epoxy groups.

[0017] Contrary to the prior art knowledge discussed above, the hardness of the blend of polyesters with epoxy-containing ethylene polymers is strongly influenced by the presence of catalyst residues used in the production of polyesters. Indeed, when ethylene polymers containing epoxy groups are mixed with polyesters containing antimony catalyst residues, the resulting polymer blend exhibits unexpectedly low strength values. However, it has been found that higher strength values ​​are obtained when either (1) a phosphorus compound is added during the manufacture of a blend using polyesters containing antimony catalyst residues or (2) when blends are formed using polyesters that do not contain residues antimony catalyst. As disclosed in JP 62-146950 and WO 00/15717 polyester compositions containing polyester containing metallic antimony, impact modifiers containing epoxy groups and a phosphorus compound show improved strength. Further, JP 62-146949 and WO 00/15716 disclose reinforced polyester compositions containing impact modifiers, containing epoxy groups and polyesters containing residues of a tin or titanium catalyst, and a titanium or germanium catalyst, respectively. Also disclosed in WO 00/23520 are articles made from polymer blends containing polymers and polyesters of ethylene containing epoxy groups with residues of antimony and phosphorus catalysts and polyesters with residues of titanium and / or germanium catalysts.

[0018] Not wanting to be related to any of the technical theories, it is believed that the residual antimony catalyst present in the polyester accelerates the epoxy-epoxy reaction in an ethylene copolymer containing epoxy groups, which can occur simultaneously with the reaction between polyester and ethylene copolymer containing epoxy groups. For example, another work using the same mixing bowl experiment by Stewart et al. has shown that a similar increase in torque can be obtained over time when antimony acetate is added directly to the ethylene copolymer containing epoxy groups in the absence of PET. The resulting ethylene copolymer containing epoxy groups is highly crosslinked, which indicates that the catalyst is highly active in promoting the reaction within the impact modifier itself. Transmission electron microscope images of an antimony catalysed PET mixture with ethylene copolymers containing epoxy groups show that the impact modifier is formed in large phases, much larger than 1 micron. These phases are too large to obtain maximum strength in PET. The phosphorus compound is believed to deactivate or partially inactivate residual antimony catalyst by blocking the epoxy-epoxy reaction and allowing the epoxy-PET reaction.

[0019] It has now been found that polymer blends containing certain polyester polymers and certain impact modifiers containing epoxy groups show improved strength when the polyester used contains aluminum atoms and alkaline earth metal atoms or alkali metal atoms or an alkali metal compound, i.e.

residues from the use of aluminum and alkaline earth metal atoms or alkali metal atoms or residues of an alkaline compound in the manufacture of polyester, in particular in combination with phosphorus atoms. In addition, it has been found that the polymer blends of the present invention prepared from PET polymers catalyzed by aluminum atoms, alkaline earth metal atoms or alkali metal atoms, or residues of an alkali compound, can be prepared using PET polymers with a lower molecular weight, while maintaining the strength of polymer blends prepared from conventional PET polymers with a much higher molecular weight. Thus, PET polymers of the inventive blends exhibit a melt viscosity closer to the polyolefin-based impact modifier, facilitating better dispersion of the impact modifier, and are less expensive to manufacture. Alternatively, it is possible to obtain a polymer blend containing a polyester polymer and having increased strength relative to a polymer blend containing a polyester blend having essentially the same It.V.

[0020] Patent application Ser. Am. No. 11 / 495,431 filed July 28, 2006 and having a joint representative herein, discloses polyester compositions that contain at least 3 ppm aluminum atoms, based on the weight of the polymer, and which further include alkaline earth metal or alkali metal atoms or residues of an alkaline compound, polymers having It.V. equal to at least 0.72 dL / g, obtained by melt phase polymerization.

[0021] Patent application Ser. Am. No. 11/229 238, filed September 16, 2005 and having a common representative herein, discloses polyester compositions containing polyester polymers, aluminum atoms, alkaline earth metal atoms or alkali metal atoms or alkali residue, and particles that improve the re-index heating of the composition.

[0022] One aspect of the present invention is based on the catalyst system used in the synthesis of one or more polyester polymers and the catalyst system affects the strength of the polymer blends of the invention containing one or more polyester polymers containing an epoxy-containing impact modifier.

[0023] Polyester food trays are conveniently produced first by extruding a polyester film and then by thermoforming the trays in a heated die. This thermoforming process both forms the tray and crystallizes the polyester resin. The film material can be produced in a separate process from the thermoforming process (sometimes called the glass-to-mold process) or the film material can be produced according to the thermoforming process (sometimes called the melt-to-mold process). Processes for extruding polyester film and thermoforming the film material to produce crystalline PET (also known as CPET) food trays are well known in the art.

3. Summary of the Invention [0024] In one aspect, the invention relates to polymer blends having improved low temperature strength, which include one or more impact modifying polymers, and one or more polyethylene terephthalate homopolymers or copolymers containing aluminum atoms in an amount example, from about 3 ppm to about 60 ppm, and one or more alkaline earth metal atoms, alkali metal atoms, or residual alkali in an amount of, for example, from about 1 ppm to about 25 ppm, in each case based on the weight of one or more polyethylene terephthalate homopolymers or copolymers.

[0025] In another aspect, the invention relates to polymer blends containing one or more impact modifiers present in an amount, for example, from about 2 weight percent to about 33 weight percent, or from 3 to 20 weight percent, or from 5 to 15 weight percent, or 20 to 30 weight percent, in each case based on the total weight of the polymer blend.

[0026] In another aspect, the invention relates to polymer blends containing one or more impact modifiers further comprising impact modifiers containing about 20 to 35 percent by weight of alkyl acrylate residues, from about 2 to about 10 percent by weight of glycidyl methacrylate residues, or mixtures thereof. and having a compound melt number from about 1 g per 10 minutes to about 30 g per 10 minutes, as determined according to ASTM D-1238. [0027] In one aspect, the invention relates to polymer blends containing one or more polyethylene terephthalate homopolymers or copolymers, further comprising aluminum atoms from about 5 ppm to about 35 ppm, or from 5 ppm to 25 ppm aluminum, based on the weight of one or more poly (ethylene terephthalate) homopolymers or copolymers.

[0028] In another aspect, the aluminum atoms are supplied to one or more polyethylene terephthalate homopolymers or copolymers as one or more of aluminum carboxylate, aluminum glycolate, basic aluminum carboxylate or aluminum alkoxide. [0029] In another aspect, the invention relates to polymer blends containing one or more polyethylene terephthalate homopolymers or copolymers, further comprising alkaline earth metal or alkali metal atoms in an amount ranging from 1 ppm to 25 ppm, relative to mass of one or more polyethylene terephthalate homopolymers or copolymers.

[0030] In yet another aspect, the invention relates to a polymer blend comprising one or more polyethylene terephthalate homopolymers or copolymers further comprising an alkaline earth metal or alkali metal, wherein the molar ratio of alkaline earth metal or alkali metal to aluminum atoms is from 0.1 to 75.

[0031] In one aspect, the invention relates to polymer blends containing one or more polyethylene terephthalate homopolymers or copolymers, further comprising one or more lithium, sodium or potassium atoms present in the amount of from 5 ppm to 18 ppm, or lithium atoms from about 7 ppm, or about 15 ppm, in each case based on the weight of one or more polyethylene terephthalate homopolymers or copolymers.

[0032] The polymer blend of the invention may further comprise one or more polyethylene terephthalate homopolymers or copolymers containing phosphorus atoms.

[0033] In one aspect, the invention relates to polymer blends containing one or more polyethylene terephthalate homopolymers or copolymers, further comprising phosphorus atoms in the amount from 10 ppm to 200 ppm, or from 10 ppm to 115 ppm, or from 10 ppm to 70 ppm, in each case based on the weight of one or more polyethylene terephthalate homopolymers or copolymers.

[0034] In another aspect, the invention relates to polymer blends containing one or more polyethylene terephthalate homopolymers or copolymers, further comprising phosphorus atoms in such a way that the molar ratio of phosphorus to the total amount of aluminum, alkaline earth and alkali metal moles ranges from 0.1 to 3.

[0035] In another aspect, the invention relates to a polymer blend containing one or more polyethylene terephthalate homopolymers or copolymers, the copolymers have an intrinsic viscosity of at least about 0.68 dL / g, or at least 0.70 dL / g, or at least 0.72 dL / g, or at least 0.75 dL / g, or at least 0.80 dL / g, or at least

0.84 dL / g obtained by melt phase polymerization.

[0036] In another aspect, the invention relates to polymer blends containing one or more polyethylene terephthalate homopolymers or copolymers, further comprising:

(a) at least 80 mole percent of terephthalic acid residues, based on the total amount of dicarboxylic acid residues constituting 100 mole percent; and (b) at least 80 mole percent ethylene glycol residues, based on the total amount of diol residues, representing 100 mole percent; and wherein the amount of aluminum atoms in one or more polyethylene terephthalate homopolymers or copolymers is from 3 ppm to 35 ppm, based on the weight of one or more polyethylene terephthalate homopolymers or copolymers, and wherein phosphorus atoms are present in one or more polyethylene terephthalate homopolymers or copolymers in an amount of 10 ppm to 115 ppm.

[0037] In yet another aspect, the invention relates to polymer blends containing one or more polyethylene terephthalate homopolymers or copolymers, further comprising:

(a) at least 92 mole percent terephthalic acid residues, based on the total dicarboxylic acid residues constituting 100 mole percent; and (b) at least 92 mole percent ethylene glycol residues, based on the total amount of diol residues comprising 100 mole percent; and wherein the amount of aluminum atoms in one or more polyethylene terephthalate homopolymers or copolymers is from 5 ppm to 25 ppm, based on the weight of one or more polyethylene terephthalate homopolymers or copolymers, and wherein phosphorus atoms are present in one or more polyethylene terephthalate homopolymers or copolymers in an amount of 10 ppm to 70 ppm.

[0038] In yet another aspect, the invention relates to polymer blends containing a nucleator present in an amount of from about 0.01% by weight to about 10% by weight or from 1% by weight to 5% by weight or from 1% by weight to 3% by weight, in each case relative to the total weight of the polymer blend. [0039] In another aspect, the nucleator in the polymer blends of the invention includes talc, carbon black, polyethylene, an aliphatic polyamide, or homo- and co-polymers of poly (tetramethylene terephthalate).

[0040] In another aspect, the polymer blend is in the form of an extruded film having a thickness of from about 300 to about 1000 microns and an intrinsic viscosity (It.V.) in the range of from about 0.6 to about 1.0 dl / g.

[0041] In another aspect, the polymer blend is in the form of a thermoformed tray having a thickness of about 300 to 1000 microns, wherein the polyester containing the polymer blend has an intrinsic viscosity (It.V.) in the range of about 0.6 to about 1 , 0 dL / g and crystallinity from about 20 percent to 35 percent.

In another aspect, a method of producing an article comprising the steps of:

(1) heating the polymer blend film to a temperature from about 125 to 165 ° C or extruding the molten film from the polymer blend;

(2) placing a heated or molten film on the mold opening having a surface temperature of about 120 to 180 ° C;

(3) causing the heated or molten film to conform to the shape of the mold to produce the shaped article;

(4) retaining the shaped article within the mold for inducing at least 24 percent or at least 28 crystallization of the polyester composition; and (5) removing the shaped article from the mold [0043] In yet another aspect, the thermoformed article is a tray.

4. Detailed description of the invention [0044] The present invention may be better understood by reference to the following detailed description of the invention.

[0045] As used herein and in the appended claims, singular forms include plural equivalents, unless the context clearly indicates otherwise. For example, reference to the processing or production of "polymer", "blend", "article", "foil" or "trays" is intended to include the processing or production of a plurality of polymers, mixtures, articles, films or trays.

[0046] In particular, when "polymer" is mentioned in the description and claims, the term should be interpreted to include not only the product of a single polymerization reaction, but also mixtures or physical mixtures of more than one polymer, while thermoplastic polymers described herein can be satisfactorily mixed together so that it can be difficult to identify the source afterwards. Thus, the expression "PET homopolymer or copolymer" should be interpreted, for example, as containing both a single polymerization product as well as a mixture of more than one PET homopolymer or copolymer, and the expression "ethylene copolymer or terpolymer" should be interpreted, for example, as containing both a single polymerization reaction product as well as a mixture of more than one ethylene copolymer or terpolymer reaction product.

[0047] References to a composition comprising "component" or "polymer" are intended to include other components or other polymers, in addition to the name, respectively. For example, when we speak of "transition metal", this expression is intended to include the use or presence of more than one transition metal. Similarly, when referring to a PET homopolymer or copolymer or a polyolefin-based copolymer or terpolymer, the following expressions are intended to include the use or presence of more than one polymer.

[0048] The term "comprising", "comprising" or "having" should be understood to mean that at least the specified compound, atom, particle or method step, etc., occurs in the composition or article or method, but does not exclude the presence of other compounds , catalysts, materials, molecules, process steps, etc., even if other such compounds, materials, particles, process steps, etc., have the same function as what is called, unless expressly excluded in the claims.

[0049] When we say that one or more impact modifiers are added or mixed with one or more PET homopolymers or copolymers (hereinafter sometimes simply simply referred to as "PET polymers"), impact modifiers can be added either in pure form or in the form of concentrate, unless the context otherwise requires.

[0050] The term "copolymer" means that at least one or more different monomers have been polymerized or grafted onto these combined monomers to form the basic structure of the polymer. The term "copolymer" as used herein describes copolymers as well as polymers containing a plurality of comonomers, such as terpolymers.

[0051] When we say film (also called sheet), we refer to the form of an amorphous or vitrified film containing the polymer blends of the invention, which have been extruded through a film die and then cooled to a temperature below the glass transition temperature such that the polyester component polymer in a polymer blend, of which the film (also called a sheet) contains less than about 10 percent crystallinity, or less than 5 percent crystallinity, or less than 2 percent crystallinity. The term foil (also called, sheet), amorphous foil (also called, amorphous sheet), or vitrified foil (also called, vitrified sheet) are synonymous and do not indicate any temperature and take into account the temperatures to which the foil is heated to enable thermoforming and crystallization. For comparison, when we talk about molten film (also called molten sheet), we refer to the molten polymer blend that is extruded from the film die and before cooling to the glass transition temperature of the polymers of the polyester component in the polymer blend from which the molten film is made .

[0052] It should also be understood that the mention of one or more process steps does not exclude the presence of additional process steps before or after the combination of said steps or intermediate method steps between these clearly defined steps, unless otherwise indicated.

[0053] Expressing a range includes all integers and their fractions in a given range. By expressing the temperature or temperature range of the process or reaction mixture or melt or applied to the melt or polymer or applied to the polymer, in all cases it means that the restriction is met if either the temperature, the actual melt or polymer temperature is used, or both specific temperature or within a certain range.

[0054] The term "ppm" as used herein means parts per million by weight.

[0055] By "metal" atoms is meant a metal atom that occupies any oxidation state, any morphological state, any structural state and any chemical state, whether added or present in a polymer or composition of matter.

[0056] By the term "residue (s)" is meant the portion of the monomer (s) that remains after polymerization of the monomer (s) to form a polymer or oligomer chain, regardless of length.

The intrinsic viscosity (It.V.) values ​​described herein are determined in units of dL / g as calculated from the inherent viscosity measured at 25 ° C with 0.5 g sample in 100 ml 60/40 w / w wt. phenol / tetrachloroethane.

[0058] When we say that the polymer blends of the invention have "improved low temperature impact strength", this means samples prepared for the polymer blends of the invention when tested as described in the experimental section, showing the transition from a plastic type of damage to a fragile type of damage, when the temperature tested decreases, at a lower temperature than polymer blends obtained from conventional PET polymers.

[0059] It has been found that polymer blends containing: one or more PET homopolymers or copolymers, produced in a molten phase, using an aluminum-containing catalyst system and one or more alkaline earth metal atoms, alkali metal atoms, or alkali residue (e.g. lithium) and one or more polyolefin copolymers containing reactive functional groups, described elsewhere herein, exhibit excellent plastic-brittle transition temperatures. For example, thermoformed trays with a thickness in the range of 18 to 22 millimeters and a degree of crystallinity in the range of 25% to 30%, obtained from the polymer blend of the present invention containing an impact modifier load in the range of 4 to 14% by weight. or 5 to 12 wt. based on the weight of the polymer blend, said blend containing polyester polymers of It.V. equal to 0.88 dL / g or less, or 0.86 dL / g or less, or 0.84 dL / g or less, or 0.82 dL / g or less, are capable of obtaining a plastic-brittle transition temperature equal to -25 ° C or less, or -28 ° C or less, or -30 ° C or less, or -35 ° C or less, or -37 ° C or less, or -40 ° C or less, or - 45 ° C or less. The method of testing the plastic-brittle transition temperature is described below using a modified measurement protocol based on ASTM D1790-02 (i.e., "Standard Test Method for Brittleness Temperature of Plastic Sheeting by Impact").

[0060] We have also found that polymer blends containing: one or more PET homopolymers or copolymers containing aluminum atoms and one or more alkaline earth metal atoms, alkali metal atoms, or alkali residue (e.g. lithium) and one or more polyolefin copolymers containing reactive functional groups described elsewhere herein, exhibit improved impact strength at low temperature compared to polymer blends made using PET polymers containing conventional catalyst systems. For example, the comparative polymer blends of the examples, which include PET polymers, prepared using conventional melt-phase polycondensation with antimony catalysts followed by solid state polymerization to obtain the final It.V., exhibit relatively low impact strength at low temperature , as the plastic-brittle transition temperature was measured compared to the inventive blends described herein.

We have also found that the polymer blends of the present invention can be prepared from polyester polymers having significantly lower It.V. than a polymer blend using polyester polymers prepared using conventional catalytic systems, such as antimony, while maintaining similar impact strength at low temperature, which eliminates the need for high It.V polyester polymers. used to make up the molecular weight loss during extrusion and now having the ability to more closely match It.V. for polyester polymers, those with impact modifier. [0062] Fall It.V. experienced with melt processing of polyester polymers into the product form decreases when the polyester polymers of the invention are used for PET polymers made with conventional catalysts. For example, there is provided a method of making an article (e.g., a sheet or thermoformed tray or foil, molten or vitrified) comprising feeding polyester polymers to an alloy processing area in which at least 95 wt. or at least 97 wt. or at least 99 wt. or 100 wt. polyester polymers introduced into the alloy processing area have initial It.V. equal to 0.90 dL / g or less, or 0.88 or less, or 0.86 or less, combining polyester polymers with an impact modifier in the melt processing area and extruding the final It.V product, the final It.V. in the product is at least 70% or at least 72% or at least 74% or at least 76% or at least 80% or at least 82% or at least 85% of the initial It.V. polyester polymers and the product has a brittle plastic transition temperature greater than the absolute value of 25 ° C, or at least -27 ° C or at least -30 ° C.

[0063] In one aspect, the invention relates to polymer blends that contain one or more polyethylene terephthalate (PET) homopolymers or copolymers, produced by a melt phase polymerization process in the presence of an aluminum containing catalyst system and one or more metal atoms. alkaline earths, alkali metal atoms, or residual alkali as a catalytic system. The polymer blends of the invention further contain one or more impact modifiers and have improved impact strength at low temperatures.

[0064] The polyester polymers of the invention include any polymer having polyester linkers, preferably also containing aromatic moieties. Among the preferred polyester polymers are polymers containing ethylene terephthalate bonds. Typical of these are polyethylene terephthalate homopolymers or copolymers. The polyester polymers may contain polymer blends, including polyethylene terephthalate homopolymers or copolymers, hereinafter described.

[0065] The polyester polymers are thermoplastic and contain aluminum atoms, for example in an amount of at least 3 ppm based on the weight of the polymer, as well as one or more alkaline earth metal atoms, alkali metal atoms, or residues of an alkaline compound, for example lithium. Such polymers usually have It.V. equal to at least 0.72 dL / g, obtained during melt phase polymerization.

[0066] Those PET homopolymers or copolymers of which the inventive blends are composed include those disclosed and claimed in US Patent Application Ser. Am. No. 11 / 495,431, filed on July 28, 2006 and having a joint representative hereby.

[0067] In another aspect, the polyester polymers contain aluminum atoms, as well as one or more alkaline earth metal atoms, alkali metal atoms, or residues of an alkaline compound, provided as a catalyst system, and further include a catalyst deactivator capable of at least partially deactivating the catalytic activity combinations of aluminum and alkaline earth metal atoms, alkali metal atoms or alkali residue.

[0068] In one aspect, polyester polymers are obtained by a process comprising polycondensation of a polyester polymer melt in the presence of aluminum atoms and one or more alkaline earth metal atoms, alkali metal atoms, or alkaline compounds.

[0069] In yet another aspect of the invention, polyester polymers suitable for use according to the invention can be made by a process that includes the step of adding phosphorus atoms to an aluminum alloy containing aluminum atoms and alkaline earth metal atoms or alkali metal atoms, or residues of an alkali compound for example atoms lithium.

[0070] The polymer blends of the invention, containing one or more PET homopolymers or copolymers, are prepared using the catalyst systems just described and described in detail below, mixed with one or more impact modifiers described elsewhere herein, show better strength impact at low temperature compared to PET polymers produced using conventional catalytic systems.

[0071] Thus, PET homopolymers or copolymers useful according to the invention contain, as a catalytic system, aluminum atoms and one or more alkaline earth atoms, alkali metal atoms, or residues of an alkaline compound, optionally inactivated by one or more catalyst deactivators.

[0072] Aluminum atoms can be present, for example in an amount of from about 1 ppm to about 35 ppm, or from 5 ppm to 25 ppm, or from 10 ppm to 20 ppm, in each case based on the total weight of the polyester polymers.

[0073] One or more alkaline earth atoms (e.g. lithium, sodium or potassium), alkali metal atoms (e.g. magnesium or calcium), or residual alkali may be present, for example in a total amount from about 1 ppm to about 25 ppm , or from 1 ppm to 20 ppm, or from 5 ppm to 18 ppm, or from 8 ppm to 15 ppm, in each case based on the total weight of one or more PET homopolymers or copolymers. [0074] In one aspect, the one or more alkaline earth atoms, alkali metal atoms, or residual alkali include lithium. In this aspect, the amount of lithium may be, for example, from about 1 ppm to about 25 ppm, or from 5 ppm to 20 ppm, or from 8 ppm to 15 ppm, in each case based on the total weight of the polyester polymers.

[0075] In the process in which the polyester polymers are prepared, the catalyst systems used can be deactivated by one or more catalyst deactivators, for example phosphorus atoms. If present, the amount of phosphorus atoms may be in the range, for example, up to about 200 ppm, or up to 150 ppm, or up to 115 ppm, or up to 70 ppm.

[0076] In one aspect, polyester polymers may have an intrinsic viscosity (It.V.) in the range, for example, from about 0.50 to about 1.1, and a log viscosity number (Ih.V) in the range from about 0.52 to about 1.2.

[0077] In a process in which polyester polymers are produced, the final It.V. in a polyester polymer, it is usually achieved completely in the melt phase polymerization process. This contrasts with conventional processes in which the molecular weight of the polyester polymer is increased to moderate It.V., solidification followed by solid phase polymerization to continue to increase the molecular weight to the final desired higher It.V. The conventional process does not allow significant deactivation of the molten phase catalyst because subsequent solid phase polymerization requires catalysis. Because the process is able to build molecular weight to the desired final It.V. completely in the molten phase, the catalyst may be at least partially deactivated to thereby avoid at least part of the catalytic activity after subsequent melting of the polyester polymer.

[0078] Thus, in one aspect, the polyester polymers contain aluminum atoms present in an amount of at least 3 ppm based on the weight of the polymer, said polymer having It.V. at least 0.72 dL / g obtained by melt phase polymerization.

[0079] In another aspect, the polyester polymers comprise: (i) aluminum atoms, (ii) alkaline earth metal atoms or alkali metal atoms or residual alkali, and (iii) a catalyst deactivator capable of at least partially deactivating the catalytic activity of the combination (and ) aluminum atoms and (ii) alkaline earth metal atoms or alkali metal atoms or residues of an alkaline compound.

[0080] The polyester polymers useful according to the invention can be crystallized during thermoforming into a food tray, and preferably contain:

(i) a carboxylic acid component containing at least 80 mole% terephthalic acid residues, and (ii) a hydroxyl component containing at least 80 mole% ethylene glycol or 1,3-propanediol residues, based on 100 mole percent of carboxylic acid component residues, and 100 mole percent hydroxyl component residues in polyester polymers.

[0081] Typically, PET polymers are prepared by reacting diols including ethylene glycol with dicarboxylic acids including terephthalic acid (as the free acid or its C₁-C₄ dialkyl ester) to produce monomers and / or oligomers of ester, which are then concentrated to form a polyester. More than one compound containing a carboxylic acid group (s) or derivative (s) thereof may be reacted during the process. All compounds that enter the process that contain a carboxylic acid group (s) or a derivative (s) thereof that become part of the polyester product contain a "carboxylic acid component". The mole% of all compounds containing the carboxylic acid group (s) or its derivative (s) that are in the product add up to 100. "Residues" of the compound (s) including the carboxylic acid group (s) or derivative (s) thereof that are in PET polymers refer to the portion of the compound (s) that remains in PET polymers after the compound (s) have been condensed with the compound (s) compounds) containing a hydroxyl group (s) and then subjected to polycondensation to form PET polymer chains of varying lengths.

[0082] More than one compound containing a hydroxyl group (s) or derivatives thereof may become part of PET polymers. All compounds that enter the process, containing a hydroxyl group (s) or derivatives thereof, which become part of PET polymers contain a hydroxyl component. The mole% of all compounds containing the hydroxyl group (s) or derivatives thereof that become part of PET polymers add up to 100. "Residues" of a functional hydroxyl compound (s) or derivatives thereof that become part of PET polymers refer to the portion of the compound (s) that remains in PET polymers after condensation of the compound (s) with the compound (s) containing the group (s) carboxylic acid or its derivative (s) followed by polycondensation to form PET polymer chains of varying lengths.

[0083] The mole% of hydroxyl and carboxylic acid residues in polyester polymers can be determined, for example, by proton NMR.

[0084] In other aspects, one or more PET homopolymers or copolymers include:

(a) a carboxylic acid component containing at least 90 mole%, or at least 92 mole%, or at least 96 mole% of terephthalic acid residues or terephthalic acid derivatives, and (b) a hydroxyl component containing at least 90 mole%, or at least 92 mole%, or at least 96 mole% ethylene glycol or 1,3-propanediol residues, more preferably ethylene glycol, based on 100 mole percent of carboxylic acid component residues and 100 mole percent of hydroxyl component residues in PET polymers.

[0085] The modifiers may be present in an amount up to 40 mole% or up to 20 mole%, or up to 10 mole%, or up to 8 mole% or up to 5 mole%, based on 100 mole percent of their respective component, carboxylic or hydroxylic acid, in the polymer. Mono-, tri- and higher functional modifiers are usually present and / or added in amounts of only up to about 8 mol% or up to 4 mol%, or up to about 2 mol%, based on 100 mol% of their respective carboxylic or hydroxylic acid component in the polymer.

[0086] In addition to the di-terephthalic acid component or the terephthalic acid derivatives, the carboxylic acid component (s) of the present PET polymers may contain one or more additional modifiers of the carboxylic acid compounds, such as naphthalene-2,6-dicarboxylic acid, naphthalene-1,6 dicarboxylic acid or mixtures thereof, monocarboxylic acid compounds, other dicarboxylic acid compounds and compounds with a higher number of carboxylic acid groups. Examples include aromatic dicarboxylic acids preferably having 8 to 14 carbon atoms, aliphatic dicarboxylic acids preferably having 4 to 12 carbon atoms, or cycloaliphatic dicarboxylic acids preferably having 8 to 12 carbon atoms. More specific examples of dicarboxylic acid modifiers useful as part of the acid component (s) are phthalic acid, isophthalic acid, naphthalene-2,6-dicarboxylic acid, cyclohexane-1,4-dicarboxylic acid, cyclohexanediacetic acid, diphenyl-4,4'-dicarboxylic acid, succinic acid, glutaric acid, adipic acid, azelaic acid, sebacic acid and the like, of which isophthalic acid and naphthalene-2,6-dicarboxylic acid are particularly suitable. It should be understood that the use of the corresponding acid anhydrides, esters and acid chlorides of these acids is encompassed by the term "carboxylic acid". It is also possible for the tricarboxylic branching agent and compounds with a higher number of carboxylic acid groups to modify PET polymers, along with the monocarboxylic acid chain terminators.

[0087] Terephthalic acid derivatives suitable for inclusion include C₁-C₄dialkyl terephthalate, such as dimethyl terephthalate and dimethylnaphthalate.

[0088] In addition to the hydroxyl component including ethylene glycol, the hydroxyl component of the present PET polymers may contain additional modifiers such as monools, diols or compounds with more hydroxyl groups. Examples of hydroxyl compound modifiers include cycloaliphatic diols preferably having from 6 to 20 carbon atoms and / or aliphatic diols preferably having from 3 to 20 carbon atoms. More specific examples of such diols include diethylene glycol; triethylene glycol; 1,4-cyclohexanedimethanol; 1,3-propanediol; butano24

1,4-diol; pentane-1,5-diol; hexane-1,6-diol; 3-methylpentanediol- (2,4); 2metylopentanodiol- (1,4); 2,2,4-trimethylpentane (1.3); 2,5-ethylhexanediol- (1,3); 2,2dietylopropanodiol- (1,3); hexanediol- (1,3); 1,4-di (hydroxyethoxy) benzene; 2,2-bis- (4-hydroxycyclohexyl) propane; 2,4-dihydroxy-1,1,3,3-tetramethyl-cyclobutane; 2,2-bis- (3-hydroxyethoxyphenyl) propane and 2,2-bis- (4-hydroxypropoxyphenyl) propane. As hydroxyl component modifiers, PET polymers may preferably contain such comonomers as 1,4-cyclohexanedimethanol and diethylene glycol.

[0089] PET polymers can be mixed with polyalkylene naphthalates or other thermoplastic polymers such as polycarbonate (PC) and polyamides. It is preferred, however, that PET polymers are mainly composed of repeating polymers of polyethylene terephthalate, for example in an amount of at least 80 wt. or at least 90 wt. or at least 95 wt. based on the total weight of PET homopolymers or copolymers.

[0090] The polyester polymers useful according to the invention therefore contain aluminum atoms that contain residues of aluminum, which is the group remaining in the polymer melt when adding aluminum atoms to the molten phase of the process for making polyester polymers, regardless of the oxidation state, morphological state, structural state or chemical state of the aluminum compound as an additive or from a residue present in the composition. The aluminum residue may be in the form identical to the aluminum compound that is added to the molten phase reaction, but will usually change because aluminum is believed to be involved in accelerating the polycondensation rate. By the term "aluminum atoms" or "aluminum" is meant the presence of aluminum in the polyester polymer detectable by any suitable analytical technique, regardless of the degree of aluminum oxidation. Suitable methods for detecting the presence of aluminum include inductively coupled plasma optical spectroscopy (ICP). The aluminum concentration is given as parts per million metal atoms based on the weight of the polyester polymers. The term "metal" does not imply a certain degree of oxidation.

[0091] Suitable examples of aluminum compounds include aluminum salts of carboxylic acids such as aluminum acetate, aluminum benzoate, aluminum lactate, aluminum laurate, aluminum stearate, aluminum alkoxides, such as aluminum ethoxide, aluminum isopropoxide, aluminum tri-butyrate, tri-tert- aluminum butyrate, mono-sec-butoxy aluminum diisopropylate, aluminum glycolates such as aluminum ethylene glycolate and aluminum chelates, wherein the alkoxy group of aluminum alkoxide is partially or fully substituted by chelating agents such as alkyl acetoacetate or acetylacetone such as aluminum aluminum acetylacetate diisopropylate, aluminum tris (ethyl acetoacetate), alkyl acetoacetate diisopropylate, bis (ethyl acetoacetate) ethyl acetate aluminum acetoacetate, aluminum acetylacetonate.

[0092] Preferred among aluminum compounds are basic aluminum salts of carboxylic acids and aluminum alkoxides. Basic aluminum salts of carboxylic acids include monobasic and dibasic compounds. The basic aluminum acetate used may be either a monohydro diacetate compound or a dihydroxy monoacetate compound or a mixture thereof. In particular, basic aluminum acetate and aluminum isopropoxide are preferred aluminum compounds. Stabilizing basic aluminum acetate with boric acid may in some cases increase its solubility. Aluminum isopropoxide is most desirable.

[0093] The amount of aluminum present in polyester polymers is usually from at least 3 ppm, or at least 5 ppm, or at least 8 ppm, or at least 10 ppm, or at least 15 ppm, or at least 20 ppm, or at least 30 ppm, and up to about 150 ppm, or up to about 100 ppm, or up to about 75 ppm, or up to about 60 ppm aluminum based on the weight of the polymer. The preferred range of aluminum is from 5 ppm to 60 ppm. Other suitable amounts include from 7 or from 10 ppm, and up to 60 ppm, or up to 40 ppm, or up to 30 ppm aluminum atoms.

[0094] The alkali metal or alkaline earth metal residues are alkali metal or alkaline earth metal atoms present in the polyester polymers in any form or degree of oxidation, or if an alkaline compound is used, followed by the remainder of the alkaline compound present in the molten polymer or final polymer or finished product, regardless of oxidation state or final physical, morphological, structural or chemical state. The word "alkali metal" or "alkaline earth metal" or "metal" includes an atom in the free state or in an oxidation state corresponding to its permissible valence in its group in the Periodic Table. The chemical state of alkali during their addition is also not limited. Alkalis can be added as a metal compound, organometallic compound or as a metal-free compound. Similarly, the chemical state of the alkaline earth metal compound or alkali metal compound at the time of addition is not limited.

[0095] Alkali and alkaline earth metals include those of Group IA and

Group IIA Periodic Table of Elements, including Li, Na, K, Rb, Cs, Mg, Ca, Sr and especially Li, Na or K. If fast pace and clarity are the main problems, Li may be beneficial. If color is the main problem, Na can be beneficial.

The metals can be added in the molten phase as metal compounds (which include a complex or salt) having counterions, among which are hydroxides, carbonates and carboxylic acids.

[0096] Other suitable alkaline compounds are those mentioned in US Pat. Ser. Am. North No. 6,156,867. These include tertiary amine compounds and quaternary ammonium compounds. Particular selected amine compounds are preferably those that do not give a more yellow color to the polymer.

[0097] The ratio of moles of alkali metal or moles of alkaline earth metals or moles of alkali to moles of aluminum (molar ratio M: Al, M: Al MR) is usually from at least 0.1, or at least 0.25 or at least 0, 5, or at least 0.75 or at least 1 or at least 2 and up to about 75, to about 50, to about 25, to about 20, to about 15, to about 10, or to about 8 or to about 6, or up to about 5.

[0098] The mass of aluminum and alkaline earth metals or alkali metals can be measured by analytical techniques to detect their quantity in finished polyester polymers or an article. Suitable methods for detecting the presence of aluminum and alkali or alkaline earth metals include inductively coupled plasma optical spectroscopy (ICP). While X-ray fluorescence spectroscopy (XRF) is a suitable method for detecting some alkaline earth metals and some alkali metals, it may not be suitable for detecting aluminum at lower levels like those found in polyester polymers. As used herein, the concentration of the alkaline earth metal or alkali metal is given as parts per million metal atoms based on the weight of the polyester polymers.

[0099] Aluminum and alkali metals or alkaline earth metals can be added in the form of a solution, a fine dispersion, a paste, a suspension or without a solvent. Preferably they are added as a liquid, in the form of a molten or slow flowing solid, which can be dosed. Most preferably they are added in the form of a liquid, in particular in a liquid solution or dispersion.

[0100] To avoid possible unwanted side reactions between the aluminum catalyst and water produced in the esterification zone, which can inhibit or deactivate the aluminum catalyst, and thus reduce the polycondensation rate, it is desirable to add aluminum compounds after the esterification reaction is substantially complete or at the beginning or during polycondensation. In a further embodiment, at least 75% or at least 85% or at least 95% of the esterification reaction (relative to conversion) is carried out in the absence of added aluminum compounds. It is desirable to add the aluminum compound and the alkali metal or alkaline earth metal compound at the same or near the same point of addition. It is most desirable to pre-mix and heat the aluminum compound and the alkali metal or alkaline earth metal compound, such as in a catalyst mixing chamber, for example, before adding it to this melt phase production line for polyester polymers.

[0101] Other metal catalysts may be present if desired. For example, Mn, Zn, Sb, Co, Ti and / or Ge catalysts can be used in combination with aluminum and alkaline earth metal or alkali metal catalysts. Titanium catalysts can be used, especially if the melt phase production involves ester exchange reactions, or the reactions can be carried out in the substantial absence of titanium. Suitable titanium catalysts include those compounds added in amounts that increase It.V. alloy of polyester polymers with at least 0.3 dL / g, if they are not deactivated, under the operating conditions used to manufacture the polyester polymer.

[0102] In one aspect, the amount of antimony oxide may be limited or antimony may be absent in the reaction mixture. Thus, the amount of antimony present can be, for example, 0 ppm, i.e. the reactions can be carried out in the absence of antimony. Alternatively, the amount of antimony present may be no more than 10 ppm, or no more than 20 ppm, or no more than 40 ppm, or no more than 60 ppm, in each case based on the weight of one or more poly (terephthalate homopolymers or copolymers) ethylene). Without wishing to be bound by theory, we believe that the presence of antimony oxide can catalyze the internal cross-linking of reactive impact modifier groups and can affect the low-impact impact performance of the polymer blend of the invention, and that polyesters using the catalyst systems described herein can significantly improve impact performance at low temperature compared to polyesters or blends containing significant amounts of antimony.

[0103] Typically, the titanium catalyst added during the ester exchange will be deactivated before polycondensation of the resulting oligomer mixture because left untreated before polycondensation, the titanium catalyst may discolor the polymer due to its high activity that includes side reactions.

However, if desired, small amounts of active titanium catalysts may be present in the catalyst system of the invention. The amount of titanium catalyst, if used, generally ranges from 2 ppm to 15 ppm, based on the weight of the polyester polymers.

[0104] Preferably, the polyester polymers of the polymer blends of the invention are formed without adding titanium, cobalt or antimony to the melt phase reaction, or even without adding any catalytically active metal or metal compound to the melt phase reaction other than an aluminum / alkali metal system or alkaline earth or alkaline earth (e.g. for measurement purposes, compounds are catalytically active if they increase the reaction rate or increase It.V. at least 0.1 dl / g, from the starting point 0.2 to 0.4 dl / g after 1 hour at 280 ° C and 0.8 mm Hg, with stirring). It should be noted, however, that one or more metals such as cobalt or manganese will likely be present at low levels in the alloy because they pass as impurities with the terephthalic acid composition made from the metal catalyzed liquid phase of the oxidation process.

[0105] Polyester polymers suitable for use in the blends of the invention may contain catalyst deactivators. Catalyst deactivators should be understood to mean a compound capable of at least partially deactivating or inhibiting the activity of the catalyst system. The compound is able to at least partially deactivate the catalyst system, if by adding it at a certain level, and only to test the effectiveness of the compound at a given level, when either one or both a) the solid state velocity in real operating conditions is reduced compared to the same polymer without deactivator ("no additive case") and / or b) when added previously, melt phase polycondensation rate under real operating conditions to a constant It.V. the target decreases, that is, it takes more time to reach It.V. target or It.V. the polymer decreases over a constant time relative to the case without addition.

[0106] Catalyst deactivator is usually added later during the manufacturing process, polyester polymers are melted to reduce the activity of the catalyst system during subsequent alloying steps in which the catalyst system can otherwise catalyze the internal crosslinking of reactive impact modifier groups. The catalyst deactivator may also help thermally stabilize polyester polymer alloys at the end of the melt polycondensation phase and during remelting, which occurs, for example, during the mixing and melting of the polymer blends of the invention according to the invention into products without which more reactions could occur to split the polymer chains in the high alloy alloy viscosity. The catalyst deactivator is not added with the addition of aluminum compounds or alkali metal compounds or alkaline earth metal compounds or alkaline compounds, nor is it added at the beginning of polycondensation because it could inhibit the catalytic activity of metal catalysts and thus the polycondensation rate. It should be noted, however, that not all types and forms of phosphorus compounds are deactivators, and if they are not, they can be added with the catalyst if necessary, or when polycondensation begins.

[0107] Suitable deactivating compounds are preferably phosphorus-containing compounds, for example phosphate triesters, acid phosphorus compounds or their ester derivatives, and amine salts of acid phosphorus-containing compounds. Acid phosphorus compounds have at least one oxygenic acid group, i.e. at least one phosphorus atom bonded with an oxygen double bond and bonded with a single bond to at least one hydroxyl group or an OH group. The number of acid groups increases with the increase in the number of hydroxyl groups associated with the phosphorus atom, which is bonded with a double bond with oxygen. Specific examples of phosphorus compounds include phosphoric acid, pyrophosphoric acid, phosphorous acid, phosphoric acid, carboxyphosphonic acids, alkylphosphonic acids, phosphonic acid derivatives, and each of their acid salts and acid esters and derivatives, including acid phosphate esters such as mono- and di phosphate esters and non-acid phosphate esters (e.g., tri-ester phosphate) such as trimethyl phosphate, triethyl phosphate, tributyl phosphate, tributoxyethyl phosphate, tris- (2-ethylhexyl) phosphate, oligomeric tri-ester phosphates, trioctyl phosphate, triphenyl phosphate, tritolyl phosphate, ethylene glycol (tris) phosphate, triethyl phosphonoacetate, methyl dimethyl phosphonate, tetraisopropyl methylenediphosphonate, and mono-, di-, and esters of phosphoric acid with ethylene glycol, diethylene glycol or 2-ethylhexanol, or mixtures thereof. Other examples include distearylpentaerythritol diphosphite, mono- and dihydrogen phosphate compounds, phosphite compounds, some inorganic phosphorus compounds that are preferably soluble in the polymer melt, poly (ethylene) hydrogen phosphate, and silyl phosphates. Fogging in particle solutions or in molded parts is an indication of the lack of solubility or limited solubility of the additive in the polymer melt. Soluble additives are more likely to deactivate / stabilize the catalytic system.

[0108] Other phosphorus compounds that can be added include amine salts of acidic phosphorus compounds. Amines can be cyclic or acyclic, they can be monomeric, oligomeric or polymeric and should be selected to minimize haze and / or maximize solubility when this is a problem. In principle, any organic group can be an organic component of an amine. Ammonia and related compounds such as ammonium hydroxide are suitable. [0109] Suitable organic amine groups include linear and branched alkyl, cycloalkyl, aryl, aralkyl, alkaryl, heteroaryl, etc. Each of these types of organic groups may be substituted or unsubstituted (e.g., hydroxyl, carboxyl, alkoxy, halogen, and similar groups). Organic groups may also contain carbonate, ketone, ether and thioether linkages as well as amide, ester, sulfoxide, epoxy and the like. This list is illustrative and not limiting.

[0110] Preferred amines are cyclic amines having a 5 to 7-membered ring, preferably a six-membered ring. These rings may consist of a single "monomeric" compound or may be part of a larger oligomer or polymer.

[0111] Preferred cyclic amines are sterically hindered amines that have organic groups substituted at ring positions adjacent to the nitrogen ring. The nitrogen ring itself can also be substituted (e.g., by alkyl, aryl, aralkyl, alkaryl and other groups). The sterically hindered amines may also contain part of an oligomeric or polymeric moiety.

[0112] Another type of suitable amine is amino acids. Amino acids having a decomposition point at or above the polymerization temperature are particularly preferred. The L enantiomer, the D enantiomer, or any mixture thereof, including racemic mixtures, may be used. The amino group and carboxylic acid group need not be attached to the same carbon. Amino acids can be alpha, beta or gamma. Substituted amino acids may be used. Amino acids with some water solubility are particularly preferred because they allow the synthesis of salts to be made in water, i.e. without VOC (volatile organic compounds).

[0113] The amount of phosphorus compound or other catalyst deactivator used in this process is effective in reducing, for example, the amount of internal crosslinking of the impact modifier reactive groups at the time of melting the polymer produced in the molten phase by partial or complete deactivation of the catalytic activity of the combination (and) of the atoms aluminum and (ii) alkaline earth metal atoms or alkali metal atoms or residues of an alkaline compound. Typical amounts of phosphorus atoms will be at least 15 ppm or at least 50 ppm or at least 100 ppm or at least 150 ppm or at least 200 ppm.

[0114] The cumulative amount of aluminum, alkali or alkaline earth metals and other catalytic metals present in the alloy should be taken into account. The ratio of moles of phosphorus to the total number of moles of aluminum and alkaline earth metals and / or alkali metals (P: M MR where M is considered to be the sum of moles of aluminum, moles of alkaline earth metals, if present, and alkali metal moles, if present, and where MR is the molar ratio) is generally at least 0.1: 1 or at least 0.3: 1 or at least 0.5: 1 or at least 0.7: 1 or at least 1: 1, and up to about 5: 1, or more preferably up to about 3: 1, or up to 2: 1, or up to 1.8: 1, or up to 1.5: 1. Avoid large amounts of phosphorus compounds to minimize losses in It.V. of the polymer at the time of adding the phosphorus compound to the molten polyester. The suitable range for P: M MR is 0.5 to 1.5.

[0115] Compounds of metals other than aluminum, alkali metals and alkaline earth metals also react with phosphorus compounds. If, in addition to aluminum, alkali metal and / or alkaline earth metal compounds, other metal compounds are present that react with phosphorus compounds, then the amount of phosphorus compound added later is desired in excess of that required to achieve the target P: M MR in order to ensure that phosphorus compounds react or combine with all reactive metals present.

[0116] The polyester polymers useful for the polymer blends of the invention contain aluminum atoms in the range of from about 5 ppm to about 100 ppm, or from 7 to 60 ppm, or 10 ppm to 30 ppm, based on the weight of the polyester polymer and the molar ratio of all atoms alkaline earth metals and alkali metals up to the number of moles of aluminum atoms may range from about 0.5: 1 to about 6: 1 or 1: 1 to 5: 1 or 2: 1 to 4: 1, and the P: M ratio range from about 0.1: 1 to about 3: 1, or 0.3: 1 to 2: 1 or 0.5: 1 to 1.5: 1.

[0117] If desired, a portion of the amount of phosphorus compound may be added at the beginning of the melt phase production process, for example when polycondensation begins and the final amount is added later or after the polycondensation but before solidification, as explained below below. To maximize polycondensation and / or production rates, most, or a significant portion or all of the phosphorus compound was later added in the melt phase production process.

[0118] Polyester polymers can be made by a melt phase reaction comprising melt forming a polyester polymer in the presence of an aluminum compound and an alkali metal or alkaline earth metal compound or alkaline compound. At least a portion of the polycondensation reaction takes place in the presence of a combination of an aluminum compound and an alkali metal compound, alkaline earth metal compound or alkaline compound. Various addition methods in which an aluminum compound, an alkali metal compound, an alkaline earth metal compound or an alkaline compound, their order of addition and their addition points are described in US Patent Application Ser. Am. North No.

11/495,431.

[0119] The reactants of the polyester precursors can be fed to the esterification reaction vessel in which the first stage of the melt phase process is carried out. The esterification process is carried out by direct esterification or by ester exchange reactions, also known as transesterification. In the second stage of the melt phase process, the oligomer mixture formed during the esterification is polycondensated to form a polyester alloy. Molecular mass of the molten substance increases constantly in the molten phase of the process to the desired It.V.

[0120] To further illustrate, a mixture of one or more dicarboxylic acids, preferably aromatic dicarboxylic acids or their ester-forming derivatives and one or more diols, such as ethylene glycol, are continuously fed to the esterification reactor operating at a temperature from about 200 ° C to 300 ° C and atmospheric pressure from about 1 psig to about 70 psig. The residence time of the reagents usually ranges from about one to about five hours. Typically, the dicarboxylic acid (s) is directly esterified with the diol (s) at elevated pressure and at a temperature of about 240 ° C to about 285 ° C. The esterification reaction is continued until at least 70% conversion of the acid or ester groups is achieved, but more typically to obtain at least 85% conversion of the acid or ester groups to produce the desired oligomeric mixture. [0121] The resulting oligomeric mixture formed in the esterification zone (which includes direct esterification and ester exchange processes) contains bis (2-hydroxyethyl) terephthalate monomer (BHET), low molecular weight oligomers, DEG, and trace amounts of by-product condensate not completely removed from esterification zones, along with other trace impurities from raw materials and / or possibly formed by catalyzed side reactions, and other optionally added ingredients such as toners and stabilizing agents. The relative amounts of BHET and oligomeric substances will vary depending on whether the process is a direct esterification process, in which case the amounts of oligomeric substances are significant or even present as main substances, or an ester exchange process, in which case the relative amount of BHET prevails over oligomeric substances. Water is removed as the esterification reaction progresses to shift the balance towards the desired products. The methanol is removed as the ester exchange reaction of the dimethyl ester and dicarboxylic acid progresses to shift the equilibrium towards the desired products. The esterification zone generally produces monomeric and oligomeric substances, if they exist, continuously in a series of one or more reactors. Alternatively, the monomeric and oligomeric substances in the oligomeric mixture can be produced in one or more batch reactors. At this stage, It.V. it is usually not measurable and is less than 0.1 dl / g. The average degree of polymerization of the molten oligomeric mixture is usually less than 15, and often less than 7.0.

[0122] The reaction for forming the oligomeric mixture is otherwise preferably not catalysed by a direct esterification process and additionally catalysed by ester exchange processes. Typical ester exchange catalysts that can be used in an ester exchange reaction include titanium and tin compounds, zinc compounds and manganese compounds, each used alone or in combination with each other. Alkali metal compounds such as lithium or sodium salts or alkaline earth metal compounds such as magnesium or calcium compounds can also be used as catalysts for ester exchange reactions. Any other catalytic materials well known to those skilled in the art are suitable.

[0123] Titanium-based catalysts present during the polycondensation reaction can negatively affect b * by giving the alloy a more yellow color. Although it is possible to deactivate the titanium-based catalyst with a stabilizer after the ester exchange reaction has ended and before polycondensation has started, it is desirable to eliminate the possibility of the titanium-based catalyst having a negative effect on the b * alloy color by conducting direct esterification or ester exchange reactions in the absence of any added titanium containing compounds. Thus, in one aspect, direct esterification or ester exchange reaction is carried out in the absence of titanium, or titanium is present in an amount, for example, not more than 1 ppm, or not more than 3 ppm, or not more than 5 ppm, or not greater than about 10 ppm, in each case based on the weight of the alloy. Suitable alternative ester exchange catalysts include zinc compounds, manganese compounds or mixtures thereof.

[0124] When the oligomeric mixture is brought to the desired percentage conversion of acid or ester groups, it is transported from the esterification zone or reactors to the polycondensation zone. The initiation of a polycondensation reaction is generally indicated either by a higher actual operating temperature than the operating temperature in the esterification zone, or by a significant pressure reduction (generally lower than atmospheric) relative to the esterification zone, or both. Typical polycondensation reactions occur at temperatures in the range of about 260 ° C to 300 ° C and below atmospheric pressure to about 350 mmHg, to 0.2 mm Hg. The residence time of the reagents usually ranges from about two to about six hours. In the polycondensation reaction, a significant amount of glycol is released by condensation of types of oligomeric esters and during a gradual increase in molecular weight.

[0125] In some processes, polycondensation reactions are initiated and continued in the melt phase in the pre-polymerization zone and completed in the melt phase in the finishing zone after which the alloy solidified to form a melt-phase polyester polymer product, generally in the form of chips, pellets or any other shape. Each zone may comprise a series of one or more separate reaction vessels operating under different conditions or the zones may be combined in one reaction vessel using one or more sub-stages operating under different conditions in a single reactor. This means that the prepolymer phase may include the use of one or more continuously operating reactors, one or more batch reactors, or even one or more reaction steps or sub-steps carried out in a single reaction vessel. The residence time of the molten material in the finishing zone relative to the residence time of the molten material in the pre-polymerization zone is not limited. For example, in some reactor designs, the pre-polymerization zone represents the first half polycondensation in terms of reaction time, while the finishing zone represents the second half polycondensation. Other reactor designs may regulate the residence time between the finishing zone and the pre-polymerization zone in a ratio of about 1.5: 1 or greater. A typical distinction between a pre-polymerization zone and a finishing zone in many designs is that the latter zone often operates at a higher temperature and / or lower pressure than the operating conditions in the pre-polymerization zone. Generally, each of these pre-polymerization and finishing zones includes one or a series of more than one reactor, and the pre-polymerization and finishing reactors are sequenced in series as part of a continuous polyester polymer production process.

[0126] The temperature applied to the polymer melt or polymer melt in at least part of the polycondensation zone is greater than 280 ° C and up to about 290 ° C. Unlike conventional practice, temperatures in the finishing zone may be lower than 280 ° C to avoid rapid increases in the formation of AA precursors. The pressure in the finishing zone may be in the range of about 0.2 to 20 mm Hg, or 0.2 to 10 mm Hg, or 0.2 to 2 mm Hg.

[0127] Alkaline earth metal compounds or alkali metal compounds can, if desired, be added to the esterification zone, before, during or after the esterification reaction, or between the esterification zone and the polycondensation zone, or when polycondensation begins. In one aspect, alkaline earth metal compounds or alkaline compounds are added before the 50% conversion of the esterification reaction mixture. For example, an alkaline earth metal or alkali metal may be added in the esterification zone between and at the beginning or during polycondensation or at the beginning or during the initial polymerization. Since the alkali metal or alkaline earth metal or alkalis act as part of the polycondensation catalyst system, it is desirable to add the alkali metal or alkaline earth metal or alkaline compound to the polyester alloy at the beginning of the polycondensation reaction to provide the benefits of shorter reaction time or greater gradual increase in molecular weight .

[0128] In the polymerization process, the polyester alloy is formed by polycondensation of the oligomer mixture in the presence of an aluminum compound. The aluminum compound may be added with a delay in the esterification zone to the oligomer mixture leaving the esterification zone, either at the start of polycondensation or to the polyester melt during polycondensation, and preferably, as mentioned above, after at least about 75% conversion in the esterification zone. However, since aluminum acts as part of the polycondensation catalyst system, it is desirable to add aluminum to the polyester alloy at the beginning of the polycondensation reaction to provide the benefit of a shorter reaction time or a larger gradual increase in molecular weight. The aluminum compound is preferably added when the percentage conversion of the final acid groups is at least 75%, more preferably when the% conversion of the final acid groups is at least 85%, and most preferably when the% conversion of the final acid groups from the esterification is at least 93% .

[0129] The aluminum compound may be added to the oligomer mixture during or after the esterification or to the polyester melt no later than when It.V. alloy reaches about 0.3 dl / g, or no later than when It.V. melt reaches 0.2 dl / g, and more preferably, to the oligomer mixture leaving the esterification zone, either before or at the start of polycondensation.

[0130] When the phosphorus compound is added to the melt phase polymerization process, the catalyst stabilizer is added to the polyester melt later during polycondensation and before solidification. The deactivator is added to the polyester melt later in the course of the polycondensation reaction when one or more of the following conditions are met or then and before the polyester melt has solidified:

a) polyester alloy reaches It.V. at least 0.50 dL / g or

b) the vacuum applied to the polyester alloy, if present, is released, at least partially, or

c) if the polyester alloy is present in the melt phase polymerization process, adding a phosphorus compound as part of the final reactor for the production of the polyester polymer, near the discharge point or between the final reactor and in front of the knife for cutting the polyester alloy, or

d) if the polyester alloy is present in the melt phase polymerization process, after at least 85% of the time for polycondensation of the polyester alloy; or

e) It.V. polyester alloy is in the It.V. range +/- 0.15 dl / g obtained after solidification; or

f) at a temperature within 30 minutes or less or 20 minutes or less solidification of the polyester alloy.

[0131] The deactivator can be added to the polyester melt once the polyester melt It.V. at least 0.50 dL / g, or at least 0.55 dL / g, or at least 0.60 dL / g, at least 0.65 dL / g, or at least 0.68 dL / g, or at at least 0.70 dL / g, or at least 0.72 dL / g or at least 0.76 dL / g, or at least 0.78 dL / g, and most preferably, regardless of when the deactivator is added, the resulting polymer leaving the melt phase production has It.V. at least 0.68 dL / g or at least 0.72 dL / g or at least 0.76 dL / g.

[0132] A deactivator may be added to the polyester alloy when It.V. the polyester alloy is equal to 0.15 dL / g, or equal to 0.10 dL / g, or equal to 0.05 dL / g, or equal to 0.030 dL / g, or equal to 0.02 It.V. obtained after collapsing. For example, a polyester alloy could have It.V. which is 0.10 dL / g below It.V. obtained after solidification or could have It.V. which is 0.10 dL / g above It.V. obtained after collapsing.

[0133] The deactivator may be added to the polyester melt at a point within 30 minutes or less, within 20 minutes or less, or within 10 minutes or less, or 5 minutes or less, or 3 minutes or less solidification of the polyester alloy. Solidification of the polyester alloy usually occurs when the alloy is forced through the die plate in a water bath and cut into pellets, or in a melt-to-mold process when the melt is injection molded into the molded article. In the broadest sense, solidification occurs when the temperature of the molten polymer is cooled below the melting point of the crystalline polymer.

[0134] Alloy reaction time from It.V. equal to 0.40 dL / g through and to It.V. in the range of at least 0.68 dL / g to 0.94 dL / g preferably 240 minutes or less, 210 minutes or less, 180 minutes or less, 150 minutes or less, or 120 minutes or less, or 90 minutes or less , or 50 minutes or less. At the times given, the vacuum is preferably used between 0.5 and 1.0 mm Hg, the temperature preferably is in the range of 275 ° C to 295 ° C. Target It.V. preferably between 0.82 and 0.92 dL / g before deactivation / stabilization.

[0135] When the molecular weight of the polymer is built up to the desired degree, it is discharged from the reactor for final polycondensation, in this case finishing to carry out pelleting. The gear pump can be used to facilitate the bulk concentration of polymer through the conduit to exit the finishing vessel. Before cutting the molten polymer, and in another aspect, before leaving the final melting phase reactor, it may be desirable to combine the mass of the polymer in the molten phase by means of a second stream, which is a liquid (which includes molten stream, dispersions, emulsions, homogeneous liquids and heterogeneous suspensions). The second stream may be introduced into the molten phase process at any stage, prior to solidification, but preferably between the knife and the entrance to the final reactor in a bulk polymer (such as finishing). The second stream can be introduced after the last half of the residence time in the finishing reactor and before the knife.

[0136] The method in which the second liquid stream is introduced and the source of the second liquid stream is not limited. For example, it may be desirable to treat and further process part of the side stream. After treatment, the treated part of the side stream can be returned to the finishing tank. In another example, it may be desirable to introduce a side stream (second liquid stream) into the finishing through an extruder or pumping means from a source independent of or different from the mass of the polymer produced in the melt phase process. [0137] The catalyst deactivator may be added to a side stream taken from the stream leaving the final polycondensation reactor and recycled back to the final reactor or at a point before the flowing stream is taken from the melt stream leaving the final reactor. In addition, other compounds such as colorants, reheat additives, or other additives may be added to the flowing stream, depending on the suitability requirements of the polymer in its final application. Any one or a mixture of these additives may be included in the second liquid stream.

[0138] Crystallized polymers catalyzed by aluminum / alkaline earth metals or alkali metals appear to be lighter or have higher L * color values ​​compared to crystalline polymers catalyzed by antimony systems under the same polymerization conditions. In addition, the subsequent addition of a phosphorus compound to polyester alloys catalyzed by aluminum / alkaline earth metals or alkali metals produces polymers that, when crystallized, have even higher L * color values ​​and higher brightness relative to the case without phosphorus, which may have a slightly higher It. V. For example, the crystallized polyester polymers obtained by the process of the invention have L * values ​​of at least 55 or at least 60, or at least 65, or at least 70.

[0139] When desired It.V. is obtained, the molten polyester polymer in the molten phase reactors can be withdrawn as the molten phase product and solidified.

[0140] The melt phase product is processed into the desired form, such as amorphous particles; however, crystallized pellets are preferred. The shape of the polyester polymer particles is not limited and may include regular or irregular separately shaped particles without restrictions in their dimensions, including stars, spheres, spheroids, globoids, cylindrical shaped pellets, conventional pellets, pellets, and any other shape, but the particles differ from sheet, foil, preforms, threads or fibers.

[0141] The method of solidifying the polyester polymer in a molten phase process is not limited. For example, the molten polyester polymer from the molten phase process may be directed through the die, or only cut or both guided through the die followed by cutting of the molten polymer. The gear pump can be used as a driving force to direct the molten polyester polymer through the matrix. Instead of using a gear pump, the molten polyester polymer can be fed to a single-screw or twin-screw screw extruder and extruded through a die, optionally at 190 ° C or higher on the extruder die. After passing through the die, the polyester polymer can be drawn into the thread, contacted with a cool liquid and cut into pellets, or the polymer can be pelleted on the die head, optionally under water. The molten polyester polymer is optionally filtered to remove particles above a predetermined size before cutting. Any conventional method and apparatus can be used for hot pelletizing or dicing, including but not limited to, dicing, thread pelleting and thread pelleting (with forced transfer), pelletizers, water ring pelletizers, hot pelletizing pelletizers, pelletizers underwater and centrifugal pelletizers.

[0142] A polyester polymer is one that is capable of crystallization. The method and apparatus used to crystallize the polyester polymer are not limited and include thermal crystallization in a gas or liquid. Crystallization can occur in a mechanically mixed tank; in a fluidized bed; mixed bed by fluid movement; tank or pipe without agitator; crystallized in a liquid medium above T._g a polyester polymer, preferably at 140 ° C to 190 ° C; or any other means known in the art. In addition, the polymer may be deformation crystallized. The polymer can also be fed to the crystallizer at a polymer temperature above its T_g (made of glass) or it can be fed to the crystallizer at a polymer temperature above its T_g. For example, the molten polymer from the melt polymerization reactor can be fed through an die plate and cut under water, and then immediately brought to the heat crystallizer without cooling to a mass temperature of the polymer pellet above T_g . Alternatively, the molten polymer may be cut, allowed to cool below its T_gand then fed to underwater heat crystallization apparatus or other suitable crystallization apparatus. Or, the molten polymer may be cut in any conventional manner, allowed to cool below its T_g, optionally stored and then crystallized.

[0143] Other ingredients may be added to the polymer blends of the present invention to enhance the performance of polyester polymers.

For example, crystallization aids, impact modifiers, surface lubricants, separating agents, antioxidants, catalyst deactivators, dyes, nucleating agents, acetaldehyde reducing compounds, other heating rate enhancers and fillers, and the like may be included. The polymer may also contain small amounts of branching agents such as trifunctional or tetrafunctional comonomers such as trimellitic anhydride, trimethylolpropane, pyromellitic dianhydride, pentaerythritol and other polyesters or polyols forming polyesters generally known in the art. All of these additions and many others, and their use are well known in the art and do not require extensive discussion. Any of these compounds can be used in the composition of the present invention.

[0144] Examples of reheat additions (the alloy added will be considered as the reheat addition as opposed to forming the reheat in situ) include activated carbon, carbon black, metallic antimony, tin, titanium nitride, titanium, copper, silver, gold, palladium, platinum, black iron oxide and the like, as well as near-infrared absorbing dyes, including but not limited to those disclosed in US Pat. Ser. Am. North. 6,197,851.

[0145] Titanium nitride particles may be added as an addition to reheating at any time during the polymerization of polyester polymers, or thereafter, including to the esterification zone, to the polycondensation zone composed of the prepolymer zone and the finishing zone, to or before the pelletizing zone, and in any at a point between or within these zones. Titanium nitride particles can also be added to solid pellets as they leave the solid state reactor. In addition, titanium nitride particles may be added to the polyester polymers in combination with other charges to the extruder used to make the films of polyester polymers, or may be fed separately to the extruder. For clarification, the particles can be added in the molten phase or in an extruder without solidifying and isolating the polyester polymer into pellets. The particles can also be added at any point in the subsequent process for producing polymer blends. In any case, at the point of addition, the particles can be added as a pure powder either in liquid or polymer concentrate and can be added to the primary or recycled PET or added as a polymer concentrate using primary PET or recycled as carrier polyester polymers.

[0146] Titanium nitride particles may have an average particle size, for example, from about 1 nm to about 1000 nm or from 1 nm to 300 nm or from 1 nm to 100 nm or from 5 nm to 30 nm, and may be present in mixtures polymeric according to the present invention, in amounts, for example, from about 0.5 ppm to about 1000 ppm, or from 1 ppm to 200, or from 1 ppm to 50 ppm.

[0147] The polymer blends of the invention further comprise an impact modifier, comprising one or more polyolefin-based homopolymers, copolymers or higher-order polymers (e.g., terpolymers), further comprising at least about 30 mole percent ethylene propylene residues or mixtures thereof. Optionally up to 90% by weight of impact modifier, this may consist of pre-formed rubber particles together with one or more polyolefin-based homopolymers, copolymers or higher order polymers (hereinafter sometimes referred to as "polyolefin polymers"). The impact modifier may be formed from a single polyolefin polymer and / or a blend of one or more polyolefin polymers. [0148] Both straight and branched chain polyolefin polymers can be useful as impact modifiers in the polymer blends of the invention and can be represented by the formula ^ANDand^-Bb^-Cc^-Dd^-Ee^-Ff^-Gg being

A is residues derived from ethylene, propylene or a mixture of ethylene and propylene;

B is carbon monoxide;

C is the residue derived from an unsaturated monomer selected from α, β ethylenically unsaturated carboxylic acids having from 3 to 8 carbon atoms and derivatives selected from alcohol monoesters containing from 1 to 30 carbon atoms, and dicarboxylic acids and dicarboxylic anhydrides and metal salts monocarboxylic, dicarboxylic and monoesters of dicarboxylic acids containing from 0 to 100 percent of the carboxylic acid groups, ionized by metal ionic neutralization of dicarboxylic acids and monoesters of dicarboxylic acids, neutralized by the amino ends of caprolactam oligomers, having a degree of polymerization of from 6 to 24;

D is a residue derived from an ethylenically unsaturated epoxy containing 4 to 11 carbon atoms;

E is the residue derived from an ethylenically unsaturated monomer selected from acrylic esters with 4 to 22 carbon atoms, vinyl esters of acids containing from 1 to 20 carbon atoms, vinyl ethers containing from 3 to 20 carbon atoms, vinyl and vinylidene halides, and nitriles containing from 3 to 6 carbon atoms;

F is a residue derived from an ethylenically unsaturated monomer having hydrocarbon side chains of from 2 to 12 carbon atoms that can be grafted with monomers containing at least one reactive group as defined in C and D, and aromatic side groups that may have from 1 to 6 substituent groups containing a total of 14 carbon atoms;

G is the residue derived from ethylenically unsaturated monomers selected from the group consisting of branched, straight chain and cyclic compounds, containing from 4 to 14 carbon atoms, and at least one additional unconjugated unsaturated carbon-carbon bond that can be grafted with a monomer having at least one reactive group, such as specified in C and D;

and a = 30 to 100 mole percent, b = 0 to 30 mole percent, c = 0 to 50 mole percent, d = 0 to 50 mole percent, e = 0 to 0 to 50 mole percent, f = 0 to 30 mole percent ig = 0 to 30 mole percent; with residues A, B, C, D, E, F and

G may be present in any order, and the impact modifier component contains at least 30 mole percent of ethylene, propylene, or mixtures thereof.

[0149] Examples of α, β-ethylenically unsaturated carboxylic acids and alkyl esters of α, β-ethylenically unsaturated carboxylic acids represented by C include acrylic, methacrylic and ethacrylic acids and their alkyl esters, the alkyl radical having from 1 to 20 carbon atoms . Examples of ethylenically unsaturated dicarboxylic acids and metal salts of monocarboxylic acids, dicarboxylic acids and monoester of dicarboxylic acid and their neutralized derivatives include maleic acid, maleic anhydride, maleic acid monoethyl ester, metal salts of maleic acid monoethyl ester, fumaric acid, fumaric acid, monoethyl ester itaconic, vinyl benzoic acid, vinyl phthalic acid, metal salts of fumaric acid monoalkyl ester, monoalkyl esters of maleic, fumaric, and itaconic acids, wherein the alkyl group contains from 1 to 20 carbon atoms. Carboxyl groups of such acids can be neutralized by amine terminated caprolactam oligomers having a degree of polymerization of 6 to 24. Examples of vinyl ethers, vinyl esters, vinyl and vinylidene halides and ethylenically unsaturated alkyl nitriles include vinyl alkyl ethers, wherein the alkyl group contains from 1 to 20 carbon atoms, vinyl benzoate, vinyl naphthenate, vinyl chloride, vinylidene fluoride and acrylonitrile. Examples of unsaturated epoxides having 4 to 11 carbon atoms include glycidyl methacrylate, glycidyl acrylate, allyl glycidyl ether, glycidyl vinyl ether, glycidyl itaconate, 3,4-epoxy-1-butene, and the like. Illustrative examples of monomers from which F residues are obtained are styrene, isobutylene, vinylnaphthalene, vinyl pyridine, vinylpyrrolidone, mono-, di- and tri-chlorostyrene, R'-styrene, where R 'is from 1 to 10 carbon atoms, butene , octene, decene, etc., and the like. Illustrative examples of monomers from which G residues can be obtained include butadiene, hexadiene, norbornadiene, isoprene, divinyl, allyl styrene and the like.

[0150] The impact modifier preferably comprises from about 0.5 to about 20 weight percent of residues containing epoxy groups derived from monomers selected from the group consisting of glycidyl methacrylate, glycidyl acrylate, allyl glycidyl ether, 3,4-epoxy-1-butene, or mixtures of any two or more of such monomers. These epoxy-containing monomers may be introduced into one or more polyolefin polymers during polymerization, or may be subsequently grafted onto one or more polyolefins. Such epoxy-containing impact modifiers are well known in the art and are available from many manufacturers.

[0151] One or more polyolefin polymers may be modified with monomers containing an epoxy functional group including, but not limited to, polyethylene; polypropylene; polybutene; ethylene-based copolymers and terpolymers including vinyl acetate, alkyl acrylate, alkyl methacrylate, where the alkyl group may be methyl, ethyl, butyl or ethylhexyl; ethylene propylene copolymers (EPR); ethylene propylene diene (EPDM); natural rubber; polybutadiene; polyisoprene; acrylonitrile butadiene (nitrile rubber); styrene-butadiene (SBR); styrene-butadiene-styrene (SBS); styrene-ethylene-butene-styrene (SEBS); acrylonitrile butadiene styrene (ABS); butyl methacrylate-butyl acrylate (acrylic core-shell); methyl methacrylate-butadiene-styrene (MBS core coating); or combinations thereof. Of these materials, those based on polyethylene are preferred.

[0152] A useful group of polyolefin polymers containing epoxy groups has, for example, the corresponding general formulas E / Y and E / X / Y, wherein:

X denotes residues derived from

<img file="PL2152805T3_D0001.tif" />

with R¹ is an alkyl group having up to 8 carbon atoms or an alkyl group with 1 to 4 carbon atoms and R² is hydrogen, methyl or ethyl and X is about 10 to 40 weight percent, or from 15 to 35 weight percent, or from 20 to 35 weight percent, of the E / X / Y copolymer;

Y is a residue derived, for example, from glycidyl methacrylate, glycidyl acrylate, allyl glycidyl ether and 3,4-epoxy-1-butene, which constitute from about 0.5 to about 20 weight percent, or from 2 to 10 weight percent, of the copolymer E / Y or E / X / Y; and

E represents ethylene residues that form the remainder of the composition.

[0153] The impact modifier may also comprise a blend or mixture of one or more E / Y, E / X or E / X / Y polyolefin polymers and optionally a polyethylene or polypropylene polymer. Thus, when we say that the impact modifier of a polymer blend according to the invention containing residues of one or more monomers, not all of the one or more polyolefin polymers need to contain such residues, and the impact modifier need not contain more than one polyolefin copolymer while a single copolymer may contain all described residues. Similarly, when we say that the impact modifier contains monomer residues, such monomer residues may be provided in one polyolefin polymer or multiple polyolefin polymers, which polyolefin polymer may or may not be the same polyolefin polymer as those containing any other described residues.

[0154] In one aspect, polyolefin polymers containing ethylene glycidyl methacrylate (GMA) (E / GMA) in an amount of about 2 to about 10 weight percent of GMA residues are suitable for impact modifiers of the present invention. In another aspect, polyolefin polymers based on methyl ethylene acrylate GMA, ethyl ethylene acrylate GMA or ethylene acrylate GMA containing about 20 to about 35 weight percent alkyl acrylate residues and from about 2 to about 10 weight percent GMA residues are suitable for impact modifiers according to the present invention. In another aspect, the concentration of epoxy-containing impact modifiers in the polymer blends of the present invention may be, for example, from about 2 to about 30 weight percent or from 3 to 15 weight percent, or from 5 to 12 weight percent, based on the total weight of the component modifying impact strength. In yet another aspect, the concentration of epoxy-containing impact modifiers in the polymer blends of the present invention may be, for example, from about 15 to about 35 weight percent or from 20 to 33 weight percent, or from 25 to 30 weight percent, based on the total weight polymer blend. For example, polymer blends containing higher impact modifier loads may be suitable for use as impact modifier concentrates as described elsewhere herein.

[0155] In another aspect, up to about 90% of one or more impact modifiers may consist of pre-formed elastomeric particles such as a core-shell rubber. This core-shell impact modifier may consist of:

(A) a core-shell polymer comprising, for example, from about 25 to about 95 wt. a first elastomeric phase polymerized from the monomer system containing, for example, from about 75 to about 99.8% by weight C₁ to C.₆ alkyl acrylate, from about 0.1 to about 5% by weight of the crosslinking monomer and from about 0.1 to about 5% by weight of the connecting monomer strain, wherein the crosslinking monomer is a polyethylene unsaturated monomer having a plurality of addition polymerizable reactive groups, with which all polymerize at essentially the same reaction rate, and said strain-linking monomer being an ethylenically unsaturated monomer having multiple addition polymerizable reactive groups, at least one of them polymerizes at a substantially different polymerization rate with at least one other of said reactive groups; and from about 75 to about 5 weight percent of the final thermoplastic polymerized rigid phase in the presence of said elastomeric phase. The latter layer may contain chemical compounds that react with one or more PET homopolymers or copolymers of the present invention to improve adhesion to the polyester polymer; and (B) a core-shell polymer based on butadiene formed between the butadiene polymer, wherein the butadiene units represent at least 50 mole percent of the total polymer and at least one vinyl monomer.

[0156] Such pre-formed particles may have either unimodal or multimodal size distribution. One example of a core-shell impact modifier useful in the present invention is available from Rohm and Haas under the trade name Paraloid EXL-5375. Similar preformed rubber particles or mixtures of different types of preformed particles can also be used.

[0157] One or more impact modifiers may be added using procedures well known in the art, such as mixing extrusion, or fed from a separate stream or pre-mixed with the other additives described in the present invention.

[0158] In one aspect, the impact modifier concentrate in a PET homopolymer or copolymer can be made and delivered to an extruder or injection molding machine at a desired rate, obtaining the desired amount of impact modifier in the polymer blend of the invention. The impact modifier concentrate will therefore contain an impact modifier at a higher concentration than the desired concentration in the polymer blend, which may be in the form of a reservoir. Thus, the impact modifier in the polymer blends of the invention may be provided as a concentrate in which the impact modifier may be present in the impact modifier concentrate in an amount, for example, at least about 10.0 wt.%, Or at least 15.0 wt. , or at least 20% by weight, or up to about 30% by weight, in each case based on the total weight of the impact modifier concentrate. The remainder of the impact modifier concentrate may contain, for example, polyester polymers or other thermoplastic polymer compatible with the polymer blends of the invention (e.g., one or more PET homopolymers or copolymers of the inventive blend).

[0159] The polymer blends of the invention can be made in a variety of ways. In one aspect, the PET homopolymer or copolymer and one or more impact modifiers may be separately dried in an atmosphere of dry air or dry nitrogen, fed to produce a molten polymer blend, and the molten polymer blend be processed to the finished product (e.g. extruded through a die line to film or sheet extrusion). In another aspect, one or more impact modifiers are introduced into the melt processing zone in such a way that the molten polymer blend comprises an impact modifier in an amount of, for example, up to 20% by weight or up to 25% by weight, or up to about 30% by weight, relative to of the total weight of the polymer blend and is collected by the die and pelleted for use as an impact modifier concentrate. The impact modifier concentrate and one or more PET homopolymers or copolymers can then be dried and introduced into the melt processing zone to produce the molten polymer blend of the invention with the desired level of impact modifier and processed to the finished product. In yet another aspect, one or more impact modifier or impact modifier concentrate can be introduced directly into molten PET homopolymers or copolymers during polymerization to produce the polymer blend of the invention.

[0160] Thus, the polymer blends of the invention can be made by any suitable method, including those that will be invented, perhaps the simplest by melt extrusion. In such a process, either alone or in combination with a product step, at least a portion of one or more PET homopolymers or copolymers may be fed to the extruder. For example, one or more impact modifier or impact modifier concentrate can be transferred separately to the extruder and introduced into the mixing zone of the extruder. The residence time can be, for example, from about 1 to about 5 minutes in a temperature range of, for example, from about 250 ° C to about 310 ° C. In another aspect, one or more impact modifier or impact modifier concentrate may be introduced into the extruder and the feed rate adjusted to provide the amount of impact modifier necessary to achieve the desired strength in products made from the polymer blend of the invention. In yet another aspect, one or more impact modifiers may be introduced into the extruder at such a rate as to provide the necessary amount of impact modifier to produce the impact modifier concentrate. The impact modifier concentrate may then be introduced into an extruder with one or more PET homopolymers or copolymers to produce the polymer blend of the invention.

[0161] A typical range for one or more impact modifiers in such impact modifier concentrates may be, for example, from about 10 wt. up to about 40% by weight, or from 15% by weight up to 33% by weight, or from 20% by weight up to 30% by weight, in each case relative to the total weight of the impact modifier concentrate. The impact modifier concentrate may be incorporated into one or more polyester homopolymers or copolymers to provide a polymer blend having an impact modifier load of at least about 2 wt%, or at least 4 wt%, or at least 6 wt%, or to 10% by weight, or up to 12% by weight, or up to about 15% by weight, in each case based on the total weight of the polymer blends of the present application.

[0162] In one aspect, at least a portion of the polyester polymer used in the present invention is melt blended with one or more impact modifiers, so as to form impact modifier concentrates containing mainly the polyester polymer used in the invention. The impact modifier concentrate can be melt blended with additional polyester polymers to provide a sufficient amount of impact modifier to the polymer blend to provide the necessary strength in products made from the polymer blend.

[0163] In another aspect, the polyester polymers can be melt blended with one or more impact modifiers to produce the polymer blends of the invention, for example by feeding one or more impact modifiers directly to a secondary manufacturing machine, such as an extruder extruder foil.

[0164] In yet another aspect, the polyester polymers can be melt blended with one or more impact modifiers to produce the polymer blends of the invention, for example by feeding one or more impact modifiers directly to the polymerization reactor to produce one or more homopolymers or PET copolymers.

[0165] One or more impact modifiers may be added to the polymerization reactor, either in pure or concentrated form, at locations including, but not limited to, at the beginning of the esterification process, near the outlet from the esterification reactor ( ie. where more than 50% conversion is present), near the inlet to the pre-polymerization reactor, near the outlet from the pre-polymerization reactor, at the point between the inlet and outlet of the pre-polymerization reactor, near the inlet to the polycondensation reactor, or at the place between the inlet and outlet from a polycondensation reactor, or at a point between the outlet of the polycondensation reactor and a die for forming pellets, sheets, fibers, bottle preforms, or the like.

[0166] In yet another aspect, one or more impact modifiers may be introduced either in pure form or as a concentrate into the final polycondensation reactor to produce one or more PET homopolymers or copolymers near the end of the polymerization process, for example at each of the following points :

a. if the molten polyester is present in the melt phase polymerization process, adding one or more polyolefin polymers as part of the final reactor for the production of the polyester polymer, near the discharge point or between the final reactor and before the knife for cutting the molten polyester, or

b. after the rise of It.V. a polymer of at least up to 0.5 dL / g, or

c. after releasing the vacuum, at least partially, if present, applied to the molten polyester; or

d. if molten polyester is present in the melt phase polymerization process after at least 75% of the time for polycondensation;

e. for molten polyester in a molten phase process at It.V. +/- 0.15 dL / g, obtained after solidification; or

f. in point It.V. at most 30 minutes before the alloy solidifies, or at most 20 minutes before the alloy solidifies.

[0167] In one aspect, the impact modifier may be added to the molten polyester, either in pure form or as a concentrate, after it has been obtained by the molten polyester It.V. at least 0.50 dL / g, or at least 0.55 dL / g, or at least 0.60 dL / g, or at least 0.65 dL / g, or at least 0.68 dL / g, or at least 0.70 dL / g, or at least 0.72 dL / g or at least 0.76 dL / g, or at least 0.78 dL / g. When the melt-only process is used to make polyester, the polymer leaving the melt phase production usually has It.V. at least 0.68 dL / g, or at least 0.72 dL / g, or at least 0.76 dL / g.

[0168] In another aspect, the impact modifier may be added either in pure form or as a concentrate to the molten polyester during or after releasing the vacuum from the molten polyester undergoing polycondensation reaction, or after applying pressure in the polycondensation zone, or a lower level reactor 10 mm Hg or less, or a lower level of 3 mm Hg or less to a level of 300 mm Hg or more, or 450 mm Hg or more, or 600 mm Hg or more, or at atmospheric or higher pressure, and preferably before the molten polyester has solidified.

[0169] In another aspect, the impact modifier may be added either in pure form or in the form of a concentrate, at a location near or at the end of the final reactor, or between the final reactor and before the knife. For example, the impact modifier can be added to the last polycondensation reactor in a proximal location to the outlet of the last polycondensation reactor, or in a pipe connecting directly or indirectly to the last polycondensation reactor and a gear pump or extruder providing the driving force of the alloy by means of a cutting die plate, wherein said pipe is directed back or near the outlet or from below to the last polycondensation reactor, or to the inlet of the pipe to the last polycondensation reactor which is closer to its outlet.

[0170] By closer to the outlet of the last polycondensation reactor, it is meant that the additive takes place in the last 25% or less relative to said reactor and in the last 15% or less of said reactor or preferably in the last 10% or less of said reactor. The percentage may be in terms of length or height, or volume of the last polycondensation reactor. Preferably the percentage is by length or height. The last percentages of length, height or volume are measured starting from the outlet of the last polycondensation reactor.

[0171] In yet another aspect, the impact modifier, either in pure form or as a concentrate, can be added to the molten polyester after at least 85% or at least 90%, or at least 95%, or at least 98%, or about 100 % of average polycondensation time. The average polycondensation time is a measure of the average elapsed time between when a given part of the alloy enters the beginning of the polycondensation zone and when that given part of the alloy reaches the exit of the molten polyester from the last polycondensation reactor. The average polycondensation time or average residence time in the polycondensation zone can be measured in marker tests or modeling.

[0172] In another aspect, the impact modifier, either in pure or concentrated form, can be added to the molten polyester when It.V. molten polyester is equal to 0.15 dL / g, or equal to 0.10 dL / g, or equal to 0.05 dL / g, or equal to 0.030 dL / g, or equal to 0.02 It.V. obtained after solidification. For example, a polyester alloy could have It.V. which is 0.10 dL / g below It.V. obtained after solidification or could have It.V. which is 0.10 dL / g above It.V. obtained after solidification.

[0173] In yet another aspect, the impact modifier may be added, either in pure form or as a concentrate, to the molten polyester at a point within 30 minutes or less, within 20 minutes or less, or within 10 minutes or less, or 5 minutes or less or 3 minutes or less, solidified molten polyester. Solidification of the polyester alloy usually occurs when the alloy is forced through the die plate in a water bath and cut into pellets, or in a melt-to-mold process when the melt is injection molded into the molded article. In the broadest sense, solidification occurs when the temperature of the molten polymer is cooled below the melting point of the crystalline polymer.

[0174] When a portion of one or more PET homopolymers or copolymers are mixed with an impact modifier to form such concentrates, the amount of impact modifier in such impact modifier concentrates can vary, for example from about 5 wt. up to about 40 wt. or from 10 wt. up to 35% by weight or from 15 wt. up to 30% by weight in each case relative to the total weight of the polymer blend. Such concentrates can then be mixed with additional amounts of one or more PET homopolymers or copolymers to obtain the amount of impact modifier finally present in the polyester compositions of the invention. The impact modifier and their values ​​are as described elsewhere in this document.

[0175] The total amount of impact modifier in the polyester compositions of the invention may vary widely and will depend in part on the low impact strength at the desired temperature for the particular application. Typically, the total amount of impact modifier in the polymer blends of the present invention may be, for example, from about 2 to about 20% by weight. or from 3 wt% to about 15 wt%, or from 5 wt% to 14 wt% in each case relative to the total weight of polyester polymers and impact modifier. When choosing the amount of impact modifier desired, a number of factors were considered, such as product design (e.g. tray design), minimum requirements for application temperature requirements for a specific product, type and composition of impact modifier (e.g. GMA concentration in one or more polyolefin polymers) and impact modifier costs that affect the amount of impact modifier used.

[0176] In general, suitable amounts of impact strength for food tray applications range from about 2.0 wt.%. or from 4 wt. up to about 16 wt. or up to 13 wt. or up to 10 wt. %. Accordingly, in another aspect, the amount of impact modifier ranges from about 2.0 wt. or from 4 wt. up to about 14 wt. or up to 12 wt. or up to 10 wt. based on the total weight of the polymer blend according to the invention.

[0177] Food trays containing crystalline PET (CPET) polymer blends have good dimensional stability over the entire temperature range encountered during both microwave and convection oven cooking. CPET food trays are conveniently produced first by extruding the polymer blend film, and then by thermoforming the film (either vitrified or melted) into trays in a heated die. Two processes are used for thermoforming food trays from crystallizable polyester polymer blends, however, the physicochemical properties of the polymer blends used in these processes are significantly different. In the first process, sometimes referred to as a "will" process roll feeding" or "in line" process, as disclosed in US Pat. Ser. Am. North. 3,496,143, the thermoforming process both forms the shape of the tray and crystallizes the film of the polymer blend, which is provided in the form of a vitrified (amorphous) film. The polyester polymer obtained from the alloy is amorphous and the development of significant crystallinity is necessary to obtain the desired physical properties. In this first method, the amorphous film (also known as the amorphous sheet) from the polymer blend is heated, and then fed into a heated mold, for example a mold formed between two heated platens. The hot foil can be made to adapt to the heated mold, for example by applying a vacuum. Crystallization is then obtained by holding the thermoformed polyester film at a temperature between its glass transition temperature, T_gand its melting point of crystals, T_m, in sufficient time keeping the thermoformed film in contact with the heated mold. Crystallization from the film in its own state (net shape) produces the desired stability at high temperature of the thermoformed product and allows its removal from the mold without damage. The desired degree of crystallinity is, for example, at least about 20%, or at least 24%, or at least 28%, or at least 32%, or up to about 34%. Thus, in this first process, the polyester film is heated from a temperature below its glass transition temperature to a temperature range in which crystallization can occur.

[0178] In a second thermoforming process, the molten polymer blend film is extruded and the molten polymer blend is thermoformed into an article by drawing the molten film into the mold prior to completely vitrifying the molten polymer blend layer. As in the first process, the film is drawn into the formed cavity by, for example, applying a vacuum and kept in contact with the heated mold, the product exhibits at least 20%, or at least 24%, or at least 28%, or at least 32%, or up to about 34% crystallinity. This process is referred to as a stop to form process. In contrast to the roller feeding process, where the polyester film is heated from a temperature below its T_g. in the alloy-to-mold process, the molten polyester film is in its T_g or above. In this way, the crystallization process is completely different and it has been generally found that crystallization nucleators perfectly suited to the roller feed process are ill-suited to the alloying process. Differences in crystallization due to the thermal history of polyester are discussed in DW van Krevelen, CHIMIA, 32 (1978), p. 279, where large differences in the density of crystallization seeds are observed with differences in thermal history, i.e. depending on whether the polymer is heated from a temperature below the glass transition temperature or cooled from the melting point to the crystallization temperature.

[0179] Unmodified crystallizable polyesters such as polyethylene terephthalate (PET) slowly crystallize after melt cooling or heating below glass transition temperature. To obtain acceptable manufacturing economics, it is essential that the rate of heat crystallization in the mold is fast.

[0180] The crystallization rate of PET and other polyesters was increased by using additives. A well known way to increase the crystallization rate is to incorporate the nucleating agent into the polyester. These crystallization rate enhancers are usually inorganic or organic solids highly dispersed in polyester. Examples of inorganic nucleators include talc, TiO_2,carbon black and zeolites, and examples of organic nucleators include polyolefins such as low density polyethylene, high density polyethylene, polypropylene, polybutene and polymethylpentene. A more comprehensive list of optional nucleators is disclosed in US Pat. Ser. Am. North 7,015,267. Such nucleators are typically used in a concentration of about 0.01 wt.% Relative to the polyester being nucleated. up to about 5 wt. The vast majority of the state of the art attempts to increase the crystallization rate of polyester products relates to crystallization during polymer cooling, especially in the injection molding process. One feature of many crystallization nucleators well known in the art, such as talc, is that they support crystallization during melt cooling as well as during heating below the glass transition temperature. These types of nucleators can be adapted to the second process discussed above (i.e. the alloy-to-mold process) in which the extruded molten film is shaped into an article and crystallizes before the molten film is cooled to a temperature below T_g molten polymer blend containing molten film.

[0181] Application of St. Ser. Am. North 20050261463 discloses crystallizable polyester compositions comprising a crystallization nucleator, an aliphatic polyamide exhibiting controlled and regulated crystallization rate during melt cooling and processable melt. The disclosed nucleators include, but are not limited to, polybutylene adipamide, polyhexylene adipamide, polyoctylene adipamide, polycaprolactam, polyamide-11, polyamide-12 and other aliphatic polyamides conceptually a condensation product of C4-12 alkylene diamine and C4-12 dicarboxylic acid or aminocarboxylic acid or cyclic lactam. While the polyamide may also contain a small portion of aromatic residues, which should be less than 20 mole percent relative to the total amount of all residues, more preferably less than 10 mole percent, and even more preferably less than 5 mole percent. Most preferably, when aromatic residues are absent.

[0182] However, if the purpose is to form an amorphous part, for example in the form of a vitrified extruded film as in the first process (i.e. roller feeding process), melt crystallization is undesirable because it may interfere with subsequent operations such as forming thermal. The best nucleation additives for processes requiring crystallization to warm the vitrified film below the glass transition temperature, as in the case of the roller feeding process described, preferably if they show little or no enhancement (or even suppress) the crystallization rate during melt cooling. Polyethylene is often used in roller feeding operations, however, US Patent No. Ser. Am. North. 6,986,864 discloses polyester compositions comprising a thermoplastic polyester, an impact modifier and a polyester crystallization rate increasing component selected from poly (tetramethylene terephthalate) homo- and copolymers. Polyester compositions exhibit increased crystallization rates, compared to similar compositions, not including impact modifier or compositions using other types of crystallization rate enhancing components, such as polyolefin-based polymers [0183] The polymer blends provided in the present invention may also contain one or more additives to improve thermal stability. The presence of one or more additives to improve thermal stability may be indicated when either the polymer blend or the tray made from it experience high temperatures for a prolonged period of time during processing or in use. Such heat stabilizers usually act by inhibiting oxidation when exposed to an oxidizing atmosphere at high temperature. Various types of heat stabilizers can be used with the most useful in the present invention, including substituted alkylated phenols, bisphenols, thiobisacrylates, aromatic amines, organic phosphites and polyphosphites. Specific aromatic amines that exhibit heat-stabilizing capabilities include primary polyamines, diarylamines, bisdiaryolamines, alkylated diarylamines, diarylamine ketone condensation products, and aldehyde imines. [0184] One example of a useful thermal stabilizer in the present invention is the Irganox 1010 antioxidant (Ciba-Geigy Corporation), which appears to be a spatial built-in polyphenol stabilizer containing tetrakis [methylene 3- (3,5-di-tert-butyl-4- hydroksyfenylopropionian)] methane. Another thermal stabilizer that can be used is 1,3,5-trimethyl-2,4,6-tris (3,5-di-t-butyl-4-hydroxybenzyl) benzene. Still another example is the PEP-Q additive available from Sandoz Chemical, of which tetrakis- (2,4-di-tert-butylphenyl) -4,4'-biphenylphosphonine is considered as the basic components. Other common stabilizing additives include calcium stearate or zinc stearate. Still other commonly used stabilizers include the antioxidant Ultranox 626 (General Electric), in which bis (2,4-di-t-butylphenyl) pentaerythritol diphosphite is considered the primary ingredient, and the antioxidant Ultranox 627A, considered to be Ultranox 626 containing about 7 percent by weight magnesium aluminum bicarbonate. Those skilled in the art can easily determine the amount of stabilizer that should be added to improve thermal stability. This amount is generally from about 0.001 to about 5 parts per hundred parts by weight of the polyester polymer comprising the polymer blend.

[0185] The new polymer blends may also contain one or more additives that inhibit the transesterification reaction between one or more polyester polymers. Such transesterification inhibiting additives are commonly used in blends of polyesters or copolyesters and polycarbonates as described in US Pat. Ser. Am. North 4,088,709. Mixture stabilizers differ in their ability to control melt mix stability and transesterification. Effective stabilizers for the polyester / polyester blend as well as the polyester / polycarbonate blends are known in the art and are commercially available. Suitable phosphorus-based transesterification inhibitors that may be present in the polymer blends of the present invention include, but are not limited to, the following phosphorus compounds:

R⁵

AND

R³ - P - R⁴ or

<img file="PL2152805T3_D0002.tif" />

each with R³, R⁴ and R⁵ represents a hydrogen atom, an alkyl group containing 1 to 20 carbon atoms, an aryl group containing from 6 to 20 carbon atoms, an arylalkyl group containing from 7 to 20 carbon atoms, or an OR group in which R is a hydrogen atom, an alkyl group containing 1 to 20 carbon atoms, an aryl group containing from 6 to 20 carbon atoms, and an arylalkyl group containing 7 to 20 carbon atoms; R³, R⁴ and R⁵ may differ from each other, or at least two of them

R³, R⁴ and R⁵ may be the same or at least two of R³, R⁴form a ring and metal salts of these phosphorus compounds.

and R⁵ may [0186] Other transesterification inhibitors that may be present include compounds having the formulas:

<img file="PL2152805T3_D0003.tif" />

with R⁶ is a divalent alkyl group having 2-12 carbon atoms or a divalent aryl group containing 6-15 carbon atoms; R³ and R⁴ are monovalent alkyl groups having 2-18 carbon atoms or a monovalent aryl group or a substituted aryl group having 6 to 15 carbon atoms;

<img file="PL2152805T3_D0004.tif" />

with R⁶ denotes divalent alkyl or poly (alkylene oxide) groups containing 2-12 carbon atoms or a divalent aryl group or substituted aryl group containing 6-15 carbon atoms.

<img file="PL2152805T3_D0005.tif" />

with R³ and R⁴ are monovalent alkyl groups having 2-18 carbon atoms or a monovalent aryl group or substituted aryl groups containing 615 carbon atoms.

[0187] Phosphorus-containing transesterification inhibitors are typically used in a concentration of from about 0.01 to 3 weight percent based on the total weight of the polymer blend. These stabilizers may be used alone or in combination and may be added to either the polyester polymer or impact modifier before or during the process of forming the polymer blend of the present invention. The suitability of a particular compound for use as a polymer blend stabilizer and determining the amount to be used as a blend stabilizer can be easily determined by preparing the polymer blend and determining the effect on crystallization rate.

[0188] Other additives commonly used for polyesters, such as pigments, dyes, plasticizers, flame retardants, demoulding agents, glidants and the like, may optionally be included if desired. Some of these additives may accelerate the crystallization of the polymer melt. Glass fibers or other inorganic fillers may also be included.

[0189] In one aspect, the polymer blends of the invention contain less than 60 wt.%, Or less than 40 wt.%, Or less than 20 wt.%, Or less than 10 wt.%, Or less than 5 wt.%. , or post-consumer recycling polyester polymer ("PCR") is not present in the composition, based on the total weight of all polyester polymers. In another aspect, the composition contains PCR in an amount greater than zero, and up to 60 wt. or up to 40 wt. or up to 20% by weight or up to 10% by weight based on the total weight of all polyester polymers.

[0190] In yet another aspect, the polymer blends of the invention may include recycled polymer blends of the invention obtained from films from which the trays were thermoformed and cut. The recycled blends of the invention can be added to the polymer blends of the invention in an amount of up to about 60 wt. or up to 40 wt. or up to 20% by weight or up to 10% by weight based on the total weight of all polymer blends. In another aspect, the polymer blends of the invention may contain polymer blends recycled in an amount less than 60 wt.%, Or less than 40 wt.%, Or less than 20 wt.%. or less than 10 wt. or less than 5 wt. or the polymer blend recycled according to the invention is not present in the composition, based on the total weight of all polyester polymers. In yet another aspect, the polymer blends of the invention, especially when they are to be used as impact modifier concentrates, can contain the polymer blends recycled according to the invention in an amount sufficient to provide 100% by weight of the polyester polymer for the inventive blend.

[0191] The polymer blends of the present invention can be made by conventional mixing techniques, e.g., the use of a single or twin screw extruder. The resulting mixtures can easily be extruded into films or sheets or injection molded, compression molded or thermoformed into desired shapes or objects.

[0192] A further aspect of the present invention relates to new molded articles, in particular food trays, made from the polymer blends of the invention. Food trays made from the inventive blends exhibit good low temperature strength to resist cracking in the event of accidental falling during storage or transportation. The trays also maintain sufficient strength and dimensional stability in the temperature range from -34 ° C to about 230 ° C.

[0193] The present invention can be further illustrated by the following examples of its preferred embodiments, although it should be understood that these examples are provided for illustrative purposes only and are not intended to limit the scope of the invention, unless otherwise indicated.

EXAMPLES

Example 1: Effect of Polyester Polymer Type on Polymer Blend Strength [0194] Polyester Polymer A (PET-A) is a PET homopolymer containing terephthalic acid and ethylene glycol residues. The polymer contained about 250 ppm Sb and 25 ppm P, supplied as a catalyst system. PET-A was prepared by melt polymerization of dicarboxylic acid residues and diols in the presence of an antimony and phosphorus catalyst to an intrinsic viscosity of about 0.72 dL / g, after which the molten PET was then solidified, pelletized and solidified to an intrinsic viscosity 0, 95 dL / g.

[0195] Polyester B polymer (PET-B) is a PET copolymer containing terephthalic acid, ethylene glycol and isophthalic acid residues, with isophthalic acid residues accounting for about 2.5 mol% of dicarboxylic residues. The polymer contained about 250 ppm Sb and 25 ppm P, supplied as a catalyst system. PET-B was prepared by melt polymerization of dicarboxylic acid residues and diols in the presence of an antimony and phosphorus catalyst to an intrinsic viscosity of about 0.66 dL / g, after which the molten PET was then solidified, pelletized and solidified to an intrinsic viscosity 0, 84 dL / g.

[0196] Polyester C (PET-C) polymer is a PET copolymer containing terephthalic acid, ethylene glycol and isophthalic acid residues with isophthalic acid residues, which is about 2.9 mol% of dicarboxylic residues. The polymer contained about 12 ppm Al, about 9 ppm Li and about 55 ppm phosphorus, provided as a catalyst; and included a heat additive and red and blue toners. PET-C was prepared by melt polymerization of dicarboxylic acid residues and diols in the presence of an aluminum and lithium catalyst, addition of reheating and toners to an intrinsic viscosity of about 0.82 dL / g, after which phosphorus was added and the molten PET was then pelletized and solidified.

[0197] PET polymers also contained low levels (less than 5 mol%) of DEG residues, occurring as a natural by-product of the melt polymerization process, or intentionally added as a modifier, for example to control the amount of DEG present in the final polymer.

[0198] Impact modifier: it is a 25/75 wt. / wt% random ethylene copolymer and 28% methyl acrylate with an alloy number (ASTM D-1238) of 7 g / 10 minutes (LOTRYL 28MA07 from Arkema) and random ethylene terpolymer, 23.5% methyl acrylate and 7.25% glycidyl methacrylate (ASTM D-1238) equal to 6.5 g / 10 minutes (LOTADER AX8900 from Arkema).

[0199] Nucleator: is a copolyether ester of poly (tetramethylene terephthalate / polyoxytetramethylene) from DuPont - Hytrel 5556

Comparative Polymer Blend 1 (i.e., Sample 10), Comparative Polymer Blend 2 (i.e., Sample 11) and Polymer Blend 3 (i.e., Sample 12) were prepared by combining the above ingredients as shown in Table 1.

Table 1: Experiment 1 Multi-stage Compositions To Make Polymer Blend 1 to 3 (Tests 10, 11 and 12, respectively)

<td>Day</td><td>Attempt</td><td>Wt.% PET A (Original)</td><td>wt% PET A (Regranulate)</td><td>Wt.% PET B (Original)</td><td>wt% PET B (Regranulate)</td><td>Wt.% PET C (Original)</td><td>wt% PET C (Regranulate)</td><td>wt% nucleating</td><td>wt% Impact Modifier</td><td>Film thickness (polished)</td>

<td> 1</td><td> 1</td><td> 89</td><td></td><td></td><td></td><td></td><td></td><td> 1</td><td> 10</td><td>22 mm</td>

<td> 1</td><td> 2</td><td></td><td></td><td> 89</td><td></td><td></td><td></td><td> 1</td><td> 10</td><td>22 mm</td>

<td> 1</td><td> 3</td><td></td><td></td><td></td><td></td><td> 89</td><td></td><td> 1</td><td> 10</td><td>22 mm</td>

<td></td><td></td><td></td><td></td><td></td><td></td><td></td><td></td><td></td><td></td><td></td>

<td> 2</td><td> 4</td><td> 44,5</td><td>50 (from day 1)</td><td></td><td></td><td></td><td></td><td> 0,5</td><td> 5</td><td>22 mm</td>

<td> 2</td><td> 5</td><td></td><td></td><td> 44,5</td><td>50 (from day 1)</td><td></td><td></td><td> 0,5</td><td> 5</td><td>22 mm</td>

<td> 2</td><td> 6</td><td></td><td></td><td></td><td></td><td> 44,5</td><td>50 (from day 1)</td><td> 0,5</td><td> 5</td><td>22 mm</td>

<td></td><td></td><td></td><td></td><td></td><td></td><td></td><td></td><td></td><td></td><td></td>

<td> 3</td><td> 7</td><td> 44,5</td><td>50 (from day 2)</td><td></td><td></td><td></td><td></td><td> 0,5</td><td> 5</td><td>22 mm</td>

<td> 3</td><td> 8</td><td></td><td></td><td> 44,5</td><td>50 (from day 2)</td><td></td><td></td><td> 0,5</td><td> 5</td><td>22 mm</td>

<td> 3</td><td> 9</td><td></td><td></td><td></td><td></td><td> 44,5</td><td>50 (from day 2)</td><td> 0,5</td><td> 5</td><td>22 mm</td>

<td></td><td></td><td></td><td></td><td></td><td></td><td></td><td></td><td></td><td></td><td></td>

<td> 4</td><td> 10</td><td> 44,5</td><td>50 (from day 3)</td><td></td><td></td><td></td><td></td><td> 0,5</td><td> 5</td><td>22 mm</td>

<td> 4</td><td> 11</td><td></td><td></td><td> 44,5</td><td>50 (from day 3)</td><td></td><td></td><td> 0,5</td><td> 5</td><td>22 mm</td>

<td> 4</td><td> 12</td><td></td><td></td><td></td><td></td><td> 44,5</td><td>50 (from day 3)</td><td> 0,5</td><td> 5</td><td>22 mm</td>

<td></td><td></td><td></td><td></td><td></td><td></td><td></td><td></td><td></td><td></td><td></td>

<td> 5</td><td> 13</td><td> 44,5</td><td>50 (from day 4)</td><td></td><td></td><td></td><td></td><td> 0,5</td><td> 5</td><td>22 mm</td>

<td> 5</td><td> 14</td><td></td><td></td><td> 44,5</td><td>50 (from day 4)</td><td></td><td></td><td> 0,5</td><td> 5</td><td>22 mm</td>

<td> 5</td><td> 15</td><td></td><td></td><td></td><td></td><td> 44,5</td><td>50 (from day 4)</td><td> 0,5</td><td> 5</td><td>22 mm</td>

<td></td><td></td><td></td><td></td><td></td><td></td><td></td><td></td><td></td><td></td><td></td>

[0200] Polymer blends were prepared by combining their respective components as specified above in Table 1, mixing the melted components and extruding the molten polymer blend into a film, after which the films were heated to a temperature of about 150 ° C, thermally formed into trays and kept in a heated tray form until the thermoformed films reach about 28% crystallinity. The test samples were then cut from the bottom of a thermoformed tray for each polymer blend.

Extrusion Protocol:

[0201] PET is a hygroscopic material and as a result its intrinsic viscosity decreases as a function of the amount of water absorbed. Initially, the PET polymer is placed in a drying funnel at 150 ° C for 8 hours with an air flow equal to 1 standard cubic foot per minute; the impact modifier was dried at 40 ° C for 8 hours with an air flow equal to 1 standard cubic foot per minute, and the nucleator was dried at 120 ° C for 8 hours with an air flow of 1 standard cubic foot per minute. In subsequent extrusion processes, regranulate (i.e. finishing of the cutting edge from the previous extruded film together with the excess of film remaining after thermoforming, the trays were cut off from the film) dried at 150 ° C for 8 hours with air flow and 1 standard cubic foot per minute. Before combining individual ingredients, the dryer temperature was reduced to 65 ° C. In the method of the present invention, the dried PET polymer, impact modifier, nucleator and regranulate for runs 2 to 5 were weighed and pre-mixed using a Maguire mixer (Model: WSB-140R) attached to the feed hopper from a Davis-Standard 2 "single screw extruder (type: Mark V) and introduced into the feed inlet of the extruder, mixed in a molten state and extruded through a film die, forming a vitrified film. To the other end of the extruder was attached a die for extruding a thermoplastic film. The conditions for the extruder and film extruder are given in Table 2:

Table 2: Standard Davis Extrusion Conditions

RPM Extruder: 80

Extruder Zone Temperatures 1-4: 575 ° F, 595 ° F, 540 ° F, 540 ° F Extruder Adapter Temperature for die 540 ° F Screen Changer Temperature: 540 ° F

Screen packs: 24 mesh - 60 mesh - 24 mesh

Power Blocks: 530 ° F

Stamping area 1: 520 ° F

Stamping zone 2: 515 ° F

Stamping zone 3: 520 ° F [0202] The extruded film in the form of a molten polymer blend was interrupted or cooled to solidify the molten film using a column of 3 cooling rollers (Davis-Standard Model EX-M-PLAR Sheet System) with a film compressed between the top of the middle roll and wrapping the foil around the middle and bottom rolls. The extruded molten polymer blend is to be brought into contact with a column of cooling rollers such that there is no orientation or basically orientation is not induced in the final film and the average crystallinity in the finished film less than about

10%, and more preferably less than about 5%. The test conditions for the respective rolls are shown in Table 3. A column of 3 rolls has been positioned relatively close to the extruder die, the distance depends on factors such as roll temperature, film extrusion speed, film thickness and roll speed. Generally, the distance from the die to the roll is about 0.25 to 5 cm.

Table 3: Conditions of the Column 3 Rolls Top roller temperature: 110 ° F Medium roll temperature: 110 ° F Lower roll temperature: 110 ° F Roller gap 0.0230 inch

Roll Pressure: 2000 psi Line Speed: 7.4 ft / min Top Roll Speed: 7.4 ft / min Middle Roll Speed: 7.4 ft / min Bottom Roll Speed: 7.4 ft / min Target Film Thickness: 22 mil [0203] Thermoforming Protocol: Glazed thermoformed foil on Hydrotrim Modes: 1620 using a 6 "to 11" aluminum rectangular mold with string ³Λ ". The film was heated to about 150 ° C and crystallized in a mold having a surface temperature of about 163 ° C for 12 to 15 seconds.

[0204] The temperature of the mold was controlled by a thermocouple that was attached to the aluminum block in which the mold was mounted. The mold surface temperature was monitored and controlled using a digital temperature controller.

The relationship between the mold and the frame was such that when the mold was moved into contact with the PET film fixed in the frame, a seal was formed between the heated foil and the mold. The vacuum system was attached to the mold. The vacuum system reached a vacuum of about 25 mmHg.

[0205] Low temperature resistance of Polymer Blends was evaluated using a modified test protocol based on ASTM D1790-02 (ie, "Standard

Test Method for Brittleness Temperature of Plastic Sheeting by Impact "). This modified test method provides a quantitative measurement of the temperature at which a sample was cut from the bottom of the formed tray from each suitable polymer blend transition from the plastic failure model to the fragile destruction model. With the modified sheet fragility test, the thermally crystallized formed tray is subjected to gradual temperature drops in order to induce a transition temperature in the tray in which the tray is reliable in a tough (i.e. hard) manner and begins to fail in a fragile manner. The temperature at which 50% of the tray samples show brittle failure is given as the ductile to brittle transition temperature (DBTT).

[0206] "Ductile to brittle" impact test: Test samples 2 "by 5 3/4" were cut from the bottom of thermoformed trays. At room temperature, the two ends of each sample were collected together to form a progressive, closed loop. The collected ends of the sample were placed on the narrow end of the 2 "by 5" card so that the loop body lay on the card. (A 2 "by 5" card was cut from the index card.) The end of the loop was attached to the end of the card through two ½ "staples from, and parallel to the 2" end of the stack.

[0207] For each sample, five analytical samples were prepared as described and added to the cooled test chamber of impact testing equipment. (The test chamber was previously allowed to stabilize for 20 minutes at the desired test temperature). After 15 minutes, each of the five analytical samples was individually placed on the anvil of the impact tester with the clamped end of the staples on the back of the card mounted in the anvil groove. In this way, the foil loop sample is centered on the anvil with the loop inverted from the rotational end of the impact arm. The impact arm was allowed to fall freely from the vertical onto the loop-shaped sample that rests on the anvil. The samples were then removed and examined for damage / destruction. Partial rupture is interpreted as damage, as well as complete division into two or more pieces.

[0208] The temperature in the test chamber was then lowered by 5 ° C, allowed to stabilize within 20 minutes, and another group of five analytical samples was placed in the chamber for 15 minutes. The test procedure and test were repeated as described above. The temperature range was checked at 5 ° C intervals to enable temperatures where all damage modes are malleable and lower temperatures where all damage modes are fragile. The number of breaks by brittle fracture (of 5 samples) was recorded. "% Destruction" versus "temperature data was analyzed using a non-linear logistic regression model and the temperature at which the regression model of the predicted 50% of the samples could be damaged was recorded at the plastic-brittle transition temperature (DBTT). Thus, the brittleness temperature was defined as the temperature at which the non-linear logistic regression model predicts that 50% of the samples tested will be damaged in brittle mode.

[0209] Impact Modifier Load: wt. impact modifier in polymer blends was determined by hydrolysis (with a base) of polymer blends followed by filtration. The filter was weighed to determine the weight of the non-PET component (i.e., impact modifier), which was compared to the total weight of the hydrolyzed polymer blend sample.

[0210] Intrinsic viscosity: The intrinsic viscosity (It.V.) values ​​described in this description are determined in units of dL / g as calculated from the log viscosity number (Ih.V.) measured at 25 ° C at 60/40 wt ./wag. phenol / tetrachloroethane. The logarithmic viscosity number is calculated based on the measured solution viscosity. The following equations describe these measurements of solution viscosity and subsequent calculations to Ih.V. and from Ih.V. to It.V:

T | inh "[In (ts / to)] / C where ni_nh = Log viscosity number at 25 ° C at polymer concentration

0.50 g / 100 mL 60% phenol and 40% 1,1,2,2-tetrachloroethane In = Natural logarithm t_s = Sample flow time through the capillary tube t_about = Time of zero solvent flow through capillary tube

C = Polymer concentration in grams per 100 ml of solvent (0.50 g / 100ml) [0211] Intrinsic viscosity is the limit value at infinite dilution of a specified polymer viscosity. It is defined by the following equations:

<img file="PL2152805T3_D0006.tif" />

where ni_nt = Intrinsic viscosity n_r = Relative viscosity = ts / to n_sp = Specific viscosity = n_r [0212] Instrument calibration involves repeated testing of standard reference material followed by the application of appropriate mathematical equations to

Accepted lh.V. Material Reference

The average of three production determinations of "accepted" values ​​of the IV value.

Calibration factor

Corrected lhV = Calculated lhV x Calibration Factor [0213] Intrinsic viscosity (It.V. or ni_nt) can be estimated from the Billmeyer equation as follows:

Tlint = 0.5 [e θ · 5 X Corrected. Hv, _ η _{+ (}q 75 _χ corrected lh.V. ) [0214] The reported intrinsic viscosities are calculated in relation to the weight of the polymer mixture dissolved in the phenol / tetrachloroethane solvent and are not corrected for the relative proportion of impact modifier contained in the respective polymer blends.

[0215] Percent Crystallinity: The crystallinity of the film is determined by differential scanning calorimetry (DSC). The sample mass for this measurement is 10 ± 1 mg. The first heating scan was carried out. The sample is heated from about 25 ° C to 290 ° C at a rate of 20 ° C / minute, and the absolute value of the melting endotherms area (one or more), minus the surface of each crystallization exotherm, is determined. This area corresponds to the net thermal energy of melting and is expressed in joules. The heat of fusion of 100% crystalline PET was taken as 119 Joules / gram, so the weight percentage of sample crystallinity is calculated as the net fusion heat divided by 119 times the weight percentage of one or more polyester polymers in the polymer blend (i.e. 119 J / g of adjusted) to take into account the amount of polyester polymer to crystallize in the polymer blend) and then multiply by 100. Unless otherwise stated, the initial melting point was also determined in each case using the same DSC scan.

[0216] Film thickness: Reported film thicknesses are an average of 20 measurements.

[0217] Intrinsic viscosity (uncorrected for non-PET components) for A to C Polymer Blend and their respective precursors after each of the numerous extrusion passes are shown in Table 1.

[0218] For example, for Polymer Blend 1:

Run 1 for Polymer Mix 1 is Test 1 in Table 1, Run 2 for Polymer Mix 1 is Test 4,

Run 3 for Polymer Mix 1 is Test 7,

Run 4 for Polymer Blend 1 is Test 10,

Run 5 for Polymer Blend 1 is Test 13, [0219] For Polymer Blend 2:

Run 1 for Polymer Mix 2 is Test 2,

Run 2 for Polymer Mix 2 is Test 5,

Etc.

Table 4: Intrinsic Viscosities (Uncorrected) for Polymer Blend 1 to 3 and precursor extrusion runs.

<td></td><td>Comparative Polymer Blend 1</td><td>Comparative Polymer Blend 2</td><td>Polymer Blend 3</td>

<td>Original</td><td> 0,95</td><td> 0,84</td><td> 0,82</td>

<td>Mileage 1</td><td> 0,831</td><td> 0,755</td><td> 0,781</td>

<td>Mileage 2</td><td> 0,769</td><td> 0,697</td><td> 0,726</td>

<td>Mileage 3</td><td> 0,753</td><td> 0,657</td><td> 0,691</td>

<td>Mileage 4</td><td> 0,719</td><td> 0,644</td><td> 0,669</td>

<td>Mileage 5</td><td> 0,762</td><td> 0,675</td><td> 0,721</td>

[0220] The increase in intrinsic viscosity from run 4 to run 5 was unexpected and indicates errors in the production of polymer blends. Thus, the film for the 4th extrusion run was thermally formed into test trays. Test samples are cut from the central part of the test tray.

Table 5: Properties of Sample Films Cut from Thermoformed Trays

Containing Polymer Blends from 1 to 3.

<td></td><td></td><td>Avg. Thickness (Mm)</td><td>Avg. Thickness mils</td><td>50% Damage Temperature C °</td><td>% Crystallinity using DSC</td><td>wt% Impact Modifier using Hydrolysis</td>

<td>Comparative Polymer Blend 1</td><td>4th course (Attempt 10)</td><td> 0,502</td><td> 19,7</td><td> -25</td><td> 30,4</td><td> 10,82</td>

<td></td><td></td><td></td><td></td><td></td><td></td><td></td>

<td>Comparative Polymer Blend 2</td><td>4th course (Attempt 11)</td><td> 0,509</td><td> 20,04</td><td> -18</td><td> 27,9</td><td> 10,75</td>

<td></td><td></td><td></td><td></td><td></td><td></td><td></td>

<td>Polymer Blend 3</td><td>4th course (Attempt 12)</td><td> 0,524</td><td> 20,8</td><td> -28</td><td> 30,6</td><td> 11,18</td>

Table 6: Frequency of Damage as a Function of Temperature for Samples Cut from 5 Thermoformed Trays Containing Polymer Blends from 1 to 3.

<td></td><td colspan="2">Comparative Polymer Blend 1</td><td colspan="2">Comparative Polymer Blend 2</td><td colspan="2">Polymer Blend 3</td>

<td>Temp.</td><td># Fractures</td><td># Test samples</td><td># Buy hello</td><td># Test samples</td><td># Buy hello</td><td># Test samples</td>

<td>-10 ° C</td><td> 0</td><td> 5</td><td> 1</td><td> 5</td><td> 0</td><td> 5</td>

<td>-15 ° C</td><td></td><td></td><td> 1</td><td> 5</td><td></td><td></td>

<td>-20 ° C</td><td> 0</td><td> 5</td><td> 4</td><td> 5</td><td> 0</td><td> 5</td>

<td>-25 ° C</td><td> 2</td><td> 5</td><td> 4</td><td> 5</td><td> 0</td><td> 5</td>

<td>-30 ° C</td><td> 5</td><td> 5</td><td> 5</td><td> 5</td><td> 4</td><td> 5</td>

<td>-35 ° C</td><td></td><td></td><td></td><td></td><td> 5</td><td> 5</td>

[0221] Additional samples from thermoformed trays for Comparative Polymer Blends 1 and 2, and Polymer Blend 3 were tested for plastic-brittle transition temperature:

Table 7: Repeated Analysis of the Film Properties of Additional Samples Cut from Thermoformed Trays Containing Polymer Blends from 1 to 3.

<td></td><td></td><td>Avg. Thickness (mm)</td><td>Avg. MILs thickness</td><td>50% Damage Temperature C °</td>

<td>Comparative Polymer Blend 1</td><td>4th mileage (Trial 10)</td><td> 0,501</td><td> 19,9</td><td> -29</td>

<td></td><td></td><td></td><td></td><td></td>

<td>Comparative Polymer Blend 2</td><td>4th mileage (Trial 11)</td><td> 0,516</td><td></td><td> -18</td>

<td></td><td></td><td></td><td></td><td></td>

<td>Polymer Blend 3</td><td>4th mileage (Trial 12)</td><td> 0,525</td><td> 21,3</td><td> -28</td>

Table 8: Repeated Failure Frequency Analysis in Temperature Function for

Additional Samples Cut From Thermoformed Containing Trays

Polymer blends from 1 to 3.

<td></td><td colspan="2">Comparative Polymer Blend 1</td><td colspan="2">Comparative Polymer Blend 2</td><td colspan="2">Polymer Blend 3</td>

<td>Temp.</td><td># Fractures</td><td># Test samples</td><td># Buy hello</td><td># Test samples</td><td># Buy hello</td><td># Test samples</td>

<td>-10 ° C</td><td></td><td></td><td></td><td></td><td></td><td></td>

<td>-15 ° C</td><td></td><td></td><td> 1</td><td> 5</td><td></td><td></td>

<td>-20 ° C</td><td> 0</td><td> 5</td><td> 4</td><td> 5</td><td> 1</td><td> 5</td>

<td>-25 ° C</td><td> 0</td><td> 5</td><td> 5</td><td> 5</td><td> 2</td><td> 5</td>

<td>-30 ° C</td><td> 3</td><td> 5</td><td></td><td></td><td> 4</td><td> 5</td>

<td>-35 ° C</td><td> 5</td><td> 5</td><td></td><td></td><td> 5</td><td> 5</td>

[0222] Surprisingly, CPET trays prepared from PET-C Polymer Blend 3 had a lower (ie better) plastic-brittle transition temperature than those prepared with PET-B, although the initial PET-C IV was lower than that for PET -B. Particularly surprising, samples cut from PET-C containing CPET trays (i.e., Polymer Blend 3) were carried out as those produced PET-A with higher It.V ..

Example 2: Effect of PET Polymer Phosphate Charging on Polymer Blend Strength [0223]

Polyester Polymer A (PET-A) was the same as previously described in Example 1

Polyester Polymer B (PET-B) was the same as previously described in Example 1

Polyester C (PET-C) was the same as previously described in Example 1

The polyester polymer D (PET-D) is a PET copolymer containing terephthalic acid, ethylene glycol and isophthalic acid residues, with isophthalic acid residues accounting for about 2.9 mol% of dicarboxylic residues. The polymer contained about 12 ppm Al, about 9 ppm Li and about 25 ppm phosphorus, provided as a catalyst system; and included a reheat additive and red and blue toners. PET-D was prepared by melt polymerization of dicarboxylic acid residues and diols in the presence of an aluminum and lithium catalyst, addition of reheating and toners, to an intrinsic viscosity of about 0.82 dL / g, then phosphorus was added and the molten PET was then pelletized and solidified .

[0224] PET polymers also contained low levels (less than 5 mol%) of DEG residues, occurring as a natural by-product of the melt polymerization process, or intentionally added as a modifier, for example to control the amount of DEG present in the final polymer.

[0225] Impact Modifier: it was the same as previously described in Example 1.

[0226] Nucleator: it was the same as previously described in Example 1.

[0227] Comparative Polymer Blend 4 (i.e., Sample 28), Comparative Polymer Blend 5 (i.e., Sample 29), Polymer Blend 7 (i.e., Sample 30) and Polymer Blend 7 (i.e., Sample 31) were prepared by combining the above ingredients as shown in Table 9.

Table 9: Experiment 2 Polymer Blend Compositions:

<td>Day</td><td>Attempt</td><td>Wt.% PET A (Original)</td><td>wt% PET A. (Regranulate)</td><td>Wt.% PET B (Original)</td><td>wt% PET B (Regranulate)</td><td>Wt.% PET C (Original)</td><td>wt% PET C (Regranulate)</td><td>Wt.% PET D (Original)</td><td>wt% PET (Regranulate)</td><td>wt% nucleating</td><td>wt% Impact Modifier</td><td>Thickness (Polished)</td>

<td> 1</td><td> 16</td><td> 89</td><td></td><td></td><td></td><td></td><td></td><td></td><td></td><td> 1</td><td> 10</td><td>22 million</td>

<td> 1</td><td> 17</td><td></td><td></td><td> 89</td><td></td><td></td><td></td><td></td><td></td><td> 1</td><td> 10</td><td>22 million</td>

<td> 1</td><td> 18</td><td></td><td></td><td></td><td></td><td> 89</td><td></td><td></td><td></td><td> 1</td><td> 10</td><td>22 million</td>

<td> 1</td><td> 19</td><td></td><td></td><td></td><td></td><td></td><td></td><td> 89</td><td></td><td> 1</td><td> 10</td><td>22 million</td>

<td></td><td></td><td></td><td></td><td></td><td></td><td></td><td></td><td></td><td></td><td></td><td></td><td></td>

<td> 2</td><td> 20</td><td> 44,5</td><td>50 (from on day 1)</td><td></td><td></td><td></td><td></td><td></td><td></td><td> 0,5</td><td> 5</td><td>22 million</td>

<td> 2</td><td> 21</td><td></td><td></td><td> 44,5</td><td>50 (from day 1)</td><td></td><td></td><td></td><td></td><td> 0,5</td><td> 5</td><td>22 million</td>

<td> 2</td><td> 22</td><td></td><td></td><td></td><td></td><td> 44,5</td><td>50 (from day 1)</td><td></td><td></td><td> 0,5</td><td> 5</td><td>22 million</td>

<td> 2</td><td> 23</td><td></td><td></td><td></td><td></td><td></td><td></td><td> 44,5</td><td>50 (from day 1)</td><td> 0,5</td><td> 5</td><td>22 million</td>

<td></td><td></td><td></td><td></td><td></td><td></td><td></td><td></td><td></td><td></td><td></td><td></td><td></td>

<td> 3</td><td> 24</td><td> 44,5</td><td>50 (from on day 2)</td><td></td><td></td><td></td><td></td><td></td><td></td><td> 0,5</td><td> 5</td><td>22 million</td>

<td> 3</td><td> 25</td><td></td><td></td><td> 44,5</td><td>50 (from day 2)</td><td></td><td></td><td></td><td></td><td> 0,5</td><td> 5</td><td>22 million</td>

<td> 3</td><td> 26</td><td></td><td></td><td></td><td></td><td> 44,5</td><td>50 (from day 2)</td><td></td><td></td><td> 0,5</td><td> 5</td><td>22 million</td>

<td> 3</td><td> 27</td><td></td><td></td><td></td><td></td><td></td><td></td><td> 44,5</td><td>50 (from day 2)</td><td> 0,5</td><td> 5</td><td>22 million</td>

<td></td><td></td><td></td><td></td><td></td><td></td><td></td><td></td><td></td><td></td><td></td><td></td><td></td>

<td>Day</td><td>Attempt</td><td>Wt.% PET A (Original)</td><td>wt% PET A. (Regranulate)</td><td>Wt.% PET B (Original)</td><td>wt% PET B (Regranulate)</td><td>Wt.% PET C (Original)</td><td>wt% PET C (Regranulate)</td><td>Wt.% PET D (Original)</td><td>wt% PET (Regranulate)</td><td>wt% nucleating</td><td>wt% Impact Modifier</td><td>Thickness (Polished)</td>

<td> 4</td><td> 28</td><td> 44,5</td><td>50 (from on day 3)</td><td></td><td></td><td></td><td></td><td></td><td></td><td> 0,5</td><td> 5</td><td>22 million</td>

<td> 4</td><td> 29</td><td></td><td></td><td> 44,5</td><td>50 (from day 3)</td><td></td><td></td><td></td><td></td><td> 0,5</td><td> 5</td><td>22 million</td>

<td> 4</td><td> 30</td><td></td><td></td><td></td><td></td><td> 44,5</td><td>50 (from day 3)</td><td></td><td></td><td> 0,5</td><td> 5</td><td>22 million</td>

<td> 4</td><td> 31</td><td></td><td></td><td></td><td></td><td></td><td></td><td> 44,5</td><td>50 (from day 3)</td><td> 0,5</td><td> 5</td><td>22 million</td>

<td></td><td></td><td></td><td></td><td></td><td></td><td></td><td></td><td></td><td></td><td></td><td></td><td></td>

[0228] The polymer blends of Example 2 were prepared as described above in Example 1, by combining their respective components as specified in Table 5 above. Samples 28 to 31 were thermally formed for testing and corresponded to Polymer Blends from 4 to 7, respectively.

[0229] Polymer Blends 4 to 7 of Example 2 were thermoformed into trays and tested for low temperature strength using the DBTT protocol as described in Example 1 above.

[0230] Intrinsic viscosity (It.V.): ItV data (uncorrected for a component other than

PET), after each of many extrusion processes for polymer blends and their precursors were as follows:

Table 10: Intrinsic Viscosities (Uncorrected) for Polymer Blend 4 to 7 and precursor extrusion runs.

<td></td><td>Comparative Polymer Blend 4</td><td>Comparative Polymer Blend 5</td><td>Polymer Blend 6</td><td>Polymer Blend 7</td>

<td>Original</td><td> 0,939</td><td> 0,818</td><td> 0,819</td><td> 0,791</td>

<td>Mileage 1</td><td> 0,818</td><td> 0,733</td><td> 0,755</td><td> 0,739</td>

<td>Mileage 2</td><td> 0,759</td><td> 0,689</td><td> 0,724</td><td> 0,698</td>

<td>Mileage 3</td><td> 0,753</td><td> 0,672</td><td> 0,720</td><td> 0,697</td>

<td>Mileage 4</td><td> 0,764</td><td> 0,688</td><td> 0,720</td><td> 0,705</td>

[0231] The film from the 4th extrusion run was thermoformed into trays. Test specimens are cut from the central part of the test trays.

Table 11: Properties of Sample Films Cut from Thermoformed Trays Containing Polymer Blends from 4 to 7.

<td></td><td></td><td>Avg. Thickness (Mm)</td><td>Avg. Thickness mils</td><td>50% Damage Temperature C °</td><td>% Crystallinity using DSC</td><td>wt% modifier Impact resistance with Hydrolysis</td>

<td>competitive Blend</td><td>4th course</td><td> 0,539</td><td> 20,2</td><td> -37</td><td> 30</td><td> 8,89</td>

<td></td><td></td><td>Avg. Thickness (Mm)</td><td>Avg. Thickness mils</td><td>50% Damage Temperature C °</td><td>% Crystallinity using DSC</td><td>wt% modifier Impact resistance with Hydrolysis</td>

<td>Polymeric 4</td><td>(Attempt 28)</td><td></td><td></td><td></td><td></td><td></td>

<td></td><td></td><td></td><td></td><td></td><td></td><td></td>

<td>Competitive Polymer Blend 5</td><td>4th course (Attempt 29)</td><td> 0,532</td><td> 20,9</td><td> -24</td><td> 27</td><td> 8,94</td>

<td></td><td></td><td></td><td></td><td></td><td></td><td></td>

<td>Polymer Blend 6</td><td>4th course (Attempt thirty)</td><td> 0,51</td><td> 20,0</td><td> -34</td><td> 26</td><td> 9,72</td>

<td></td><td></td><td></td><td></td><td></td><td></td><td></td>

<td>Polymer Blend 7</td><td>4th course (Attempt 31)</td><td> 0,507</td><td> 19,6</td><td> -36</td><td> 29</td><td> 8,97</td>

Table 12: Frequency of Damage as a Function of Temperature for Samples Cut from Thermoformed Trays Containing Polymer Blends from 4 to 7.

<td></td><td colspan="2">Comparative Polymer Blend A</td><td colspan="2">Comparative Polymer Blend B</td><td colspan="2">Polymer Blend C</td><td colspan="2">Polymer Blend D</td>

<td>Temp.</td><td># Fractures</td><td># Test samples</td><td># Fractures</td><td># Test samples</td><td># Fractures</td><td># Test samples</td><td># Fractures</td><td># Test samples</td>

<td>-15 ° C</td><td> 0</td><td> 5</td><td> 0</td><td> 5</td><td> 0</td><td> 5</td><td> 0</td><td> 5</td>

<td>-20 ° C</td><td> 0</td><td> 5</td><td> 0</td><td> 5</td><td> 0</td><td> 5</td><td> 0</td><td> 5</td>

<td>-25 ° C</td><td> 0</td><td> 5</td><td> 3</td><td> 5</td><td> 0</td><td> 5</td><td> 0</td><td> 5</td>

<td>-30 ° C</td><td> 1</td><td> 5</td><td> 4</td><td> 5</td><td> 0</td><td> 5</td><td> 2</td><td> 5</td>

<td>-35 ° C</td><td> 0</td><td> 5</td><td> 5</td><td> 5</td><td> 3</td><td> 5</td><td> 4</td><td> 5</td>

<td>-40 ° C</td><td> 4</td><td> 5</td><td></td><td></td><td> 5</td><td> 5</td><td> 5</td><td> 5</td>

<td>-45 ° C</td><td> 4</td><td> 5</td><td></td><td></td><td></td><td></td><td></td><td></td>

<td>-50 ° C</td><td> 5</td><td> 5</td><td></td><td></td><td></td><td></td><td></td><td></td>

[0232] For melt resins only, there was less IV loss during extrusion compared to solid resins.

[0233] Trays made of Li / Al catalyzed PET melt only (e.g. PET C and D) showed less IV loss during extrusion compared to solids (i.e. PET A and B) and unexpectedly showed lower ( better) plastic-brittle transition temperatures than with PET B, which has comparable It.V. In addition, the low-impact impact performance of trays made from the polymer blend of the invention, using PET polymers only in the melt phase approached those made from the high It.V. homopolymer. 12822. Both phosphorus levels in the materials only in the molten phase gave good yields.