Zero oxygen permeation plastic bottle for beer and other applications

IS 2 147 998 T3

DESCRIPTION

Plastic bottle with zero oxygen permeation for beers and other applications.

Field of the invention

The invention relates to multilayer plastic containers with greater resistance to oxygen permeability and to compositions and processes for the production of multilayer plastic bottles.

Foundation of the invention

To be technically acceptable, beer containers (glass, metal, or plastic) must keep the beer contained within in a nearly oxygen-free environment. A generally accepted industry standard is that oxygen introduction into the bottle should be a maximum of 1 ppm during the planned pot life of bottled beer. In addition, not only must oxygen be excluded from bottled beer, but the escape of carbon dioxide from beer through the walls of the bottle must be eliminated, or when it is kept within defined standards.

Oxygen can be present in bottled beer from at least three separate sources. In some cases, undesirable oxygen (from the air) is not completely removed from the space above the liquid in the beer bottle during the beer filling process. The oxygen that emerges from this source is known as headspace oxygen. Still beer packaged in cans is susceptible to the presence of headspace oxygen. In glass beer bottles, capped in the usual way, oxygen can penetrate into the bottle during storage by permeation through the medium used as a gasket in the bottle cap. A third source of oxygen, in bottled beer, is specific to the use of plastic bottles. Oxygen, coming from the air, has the ability to permeate many traditional bottling polyesters and end up penetrating the cavity of the bottle. Also, when it comes to plastic bottles, oxygen can be dissolved or adsorbed on the plastic. Dissolved or adsorbed oxygen on the plastic walls of the bottle can be desorbed and end up in the bottle cavity. Such desorbed oxygen is indistinguishable from headspace oxygen once it is inside the cavity of the bottle, except that it can be considered as a possible continuous source of oxygen that must be consumed or depleted. For our purposes, desorbed oxygen can be considered as a contributing factor to headspace oxygen. The dissolved oxygen in the plastic wall is indistinguishable from the oxygen trying to permeate through the plastic walls of the bottle. For our purposes, the dissolved oxygen in the plastic walls of the bottle will be considered the same as the oxygen trying to permeate through the walls of the bottle. In short, then, beer packed in metal cans is generally at risk exclusively as far as headspace oxygen is concerned. Beer, in glass bottles, is generally at risk with respect to headspace oxygen and also with respect to oxygen permeation through the closure means of the bottle, especially the seals or covers of the set capsules. Beer in plastic bottles is subject to the risk of oxygen from the two sources indicated above and also by the permeation of oxygen through the wall of the bottle into the cavity of the bottle. These considerations apply to other products packaged in cans and bottles as well, although the effects of oxygen can vary considerably depending on the sensitivity of the product to oxygen.

Although bottling of beer in plastic bottles is still in its infancy, the foregoing regarding the means by which oxygen is present in the cavity of a plastic bottle has been well documented in the art, not just in for bottling applications with oxygen requirements as stringent as those for beer, but also with respect to less rigorous applications than those corresponding to beer bottling. Attempts to solve these problems in plastic bottles have frequently comprised the use of multilayer bottles where at least one of the layers comprises a polymer (eg ethylene-vinyl alcohol copolymer, EVOH) that has a higher passive resistance to permeability. of oxygen when compared to bottling polyesters which are usually polyethylene terephthalate (PET). There are drawbacks to such approaches, including the following: (1) the bottles are no longer suitable for recycling with other polyester (PET) bottles due to the presence of a second incompatible polymer (EVOH), (2) the bottles tend to delaminate at the PET / EVOH interfaces, even when such delamination can be somewhat reduced (at additional cost) by employing adhesive tie layers, (3) the differences in melting temperature and other phasic properties between PET and EVOH are the cause of numerous problems in the bottle manufacturing process, and (4) the use of a passive oxygen barrier, for example a layer of EVOH, tends to keep oxygen from the headspace

ES 2 147 998 T3 occluded within the cavity of the bottle instead of being removed.

This invention addresses these and other problems related to prior art efforts to manufacture plastic bottles with zero and near zero oxygen permeation.

Summary of the invention and analysis of the current state of the art

Therefore, in a general sense, this invention relates to novelty bottles and to a for the production of multilayer plastic bottles with practically zero oxygen permeation. By "practically zero oxygen permeation" it is meant that the oxygen making its way into the bottled product does so in an amount that is only barely measurable with instruments that measure such permeation. In the absence of a specific amount of oxygen, practically zero oxygen permeation was considered as 1 ppm oxygen, in terms of the weight of the bottled product, relative to the specific shelf life of the bottled product. The multilayer plastic bottles of this invention are suitable for recycling with other polyester bottles; they have excellent rigidity, they have good transparency when such transparency is desirable; resist delamination; they do not need tie layers, and they also have the ability to prevent oxygen (from the air) from entering the bottle cavity, but they also have the ability to consume or deplete the presence of undesirable oxygen in the bottle cavity. The novelty bottles of this invention comprise the use of modern processes and equipment for the production of multilayer bottles in conjunction with the deployment of at least one layer (of the multilayer plastic bottle) comprising an oxygen-scavenging formulation of the copolyether that is an active oxygen scavenger. Active oxygen scavengers consume (or otherwise deplete) the oxygen in a given environment. It is indicated in the jointly pending application, A multilayer bottle with zero oxygen permeation would have sufficient oxygen scavenging capacity to consume any undesirable oxygen (headspace) in a bottle cavity and still have sufficient remaining capacity to consume oxygen in the ratio at which it reaches the scavenger layer. from air outside the container during the necessary shelf life of the filled bottle.

Applicants' oxygen scavenging systems are block copolycondensates comprising predominantly polycondensate segments and an oxygen scavenging amount of polyolefin oligomoeric segments. By the term "predominantly" it is meant that at least 50% by weight of the copolycondensate can be attributed to segments of the polycondensate. Preferred polycondensate segments, especially for use in bottling, are polyether segments. For layers in multilayer bottles in which some of the layers are made of PET, or of modified polyesters such as PETI, PETN, APET, PETB and / or PEN, segments of the block copolyether comprising these same polyesters are especially preferred. One main reason is that copolyethers more accurately emulate the polyether from which their polyether segments are derived. The aforementioned polyesters and the various bottling modified polyesters, which are considered safe for use with foodstuffs, as listed in 22 CFR §177.1630 are the polyesters of choice for bottles due to their transparency, rigidity, and long history of use for the storage of food products and beverages. It is understood that the numerous references made to PET in this specification will comprise (unless otherwise indicated) not only PET, but will comprise PET as commonly used in various modified forms for bottling including, but not limited to , the list of modified polyesters mentioned above and subsequently defined in more detail herein.

The polyolefin oligomeric segments are prepared for copolycondensation first with the polyolefin oligomeric segments with end groups capable of entering polycondensation reactions. This is an important feature because polyolefin oligoomers are, in fact, additive polyomers. The functionalization of end-group polyolefin oligoomers provides a convenient method for incorporating additive polymer segments into a copolycondensate. A preferred polyolefin oligoomer is polybutadiene (PBD) because it has good oxygen scavenging ability and reacts quickly with oxygen, especially in the presence of a transition metal catalyst, for example cobalt, and in the presence of benzophenone, or cobalt. and benzophenone.

One of the prominent characteristics of the oxygen scavenging copolyethers of this invention is their ability to scavenge oxygen in the presence or absence of water or even moisture. While much of the discussion of this discovery focuses on zero oxygen permeation beer bottles, many other materials are suitable for bottling and / or packaging in zero and near zero oxygen permeation packaging environments, planned and understood. for this invention. Other examples of perishable food and beverage products, other than beer, for which it would be suitable

ES 2 147 998 T3 a bottle, jar, or specialized container, with zero oxygen permeation, are well known and include wines, fruit juices, beverage concentrates, isotonic, flavored teas, products based on tomato such as ketchup, barbecue sauces and sauces, vinegar, mayonnaise, baby foods, nuts and dehydrated food products of all varieties. Non-food items, which require zero oxygen permeation packaging, will include oxygen sensitive electronic components.

One reason that the adequacy of this invention is so appropriate has to do with the current trend, in the food and beverage industries, to offer the consumer information regarding the freshness of the product. Either by legislation or on a voluntary basis, it has become quite normal practice, in the food and beverage industries, to provide an "expiration date" or "best before" or "packaging", not codified, easily understandable, clearly printed on the bottle or container. This long-standing need to satisfy consumer awareness of product freshness has recently been very well exemplified by an advertising campaign from major US breweries that characterize what they call a "date of expiration." bottled ”in bottled beer. These consumer information data on containers and bottles assist the consumer in determining the suitability and freshness of the product. These data are also valuable in the application of this invention, since the knowledge of the specific useful storage duration for a given product allows an easy calculation of the oxygen elimination capacity necessary to maintain a zero (or almost zero) oxygen permeation. ) during the maximum planned shelf life.

The adjustment of the oxygen scavenging capacity of the bottles of this invention, to guarantee zero oxygen permeation, varies not only by product but also within a given product line. In a document titled REQUIREMENTS FOR PLASTIC BERR PACKAGES, presented at the “Future-Pak '96” conference by Dr. Nick J. Huige of the Miller Brewing Company, it was described that, for US domestic beers, a maximum introduction of 1000 ppb (1 ppm) in a useful storage period of 120 days, when stored at 75 F (24 ° C) was generally recognized as the industry standard. It is common practice to remove any beer that is 120 days old (that is, 120 days from the bottling date) from retail shelves and destroy it. It is made with many US beers not only due to the possible presence of oxygen, but also due to other changes that occur once the beer has been bottled, especially the appearance of a moldy or foul-smelling character. . Huige also estimates that approximately 95% of beer from major US breweries reaches the consumer within 60 days of the bottling date. However, to meet the industry standard, a planned shelf life of zero oxygen permeation for 120 days at 75^°F (24^°C) is a realistic target for bottling beer sourced from major US breweries.

For small US brewers and European brewers, the requirements may be entirely different. For small US brewers, 95% of the product is unlikely to reach the consumer within 60 days of the bottling date. Likewise, European brewers (and to a lesser extent, small brewers in the US) consider it desirable that bottled beer take into account what is characterized by beer tasters as a "paper / cartoon" flavor. ", Which is a characteristic related to at least partial oxidation of the beer in the bottle. AND^andThis is strictly an undesirable attribute when it comes to American beers, balanced in a more delicate way, with a lighter body. From these few considerations, it is clear that setting the oxygen permeation rate, including the shelf life requirements for zero oxygen permeation storage, is not always an easy matter. However, it can be predicted and calculated in most cases and deduced empirically in other cases. Once known, the methods for adjusting the oxygen scavenging capacity and / or the zero oxygen permeation shelf life of the bottle can be achieved by a combination of the various methods of this invention, as will be discussed in detail. more ahead.

Published PCT application (WO 96/18686, published June 20, 1996) describes the use of aliphatic polyketone materials as oxygen scavengers. This reference does not present examples of bottles made with zero oxygen permeation. There are no experimental data in the reference other than the permeability coefficients of the primary aliphatic polyketone, and it is not clear whether these data were experimental or provided by the resin manufacturer. The oxygen elimination behavior, described in the reference, is insufficient, by several orders of magnitude, to maintain a null oxygen permeability, that is, the elimination capacity is insufficient to consume the oxygen.

ES 2 147 998 T3 rate at which it reaches the permeate remover layer through the outer PET layer.

Japanese Patent Document 3-275327, published 06/12/91 describes a blown bottle having walls including an "oxygen impermeable" layer of a "methoxyarylenediamine". The data in this reference shows a reduction in oxygen permeability that is reduced to 28% of the amount that passes using only PET bottle walls. This amount is inconsistent with the purpose of this invention which is zero oxygen permeation.

A single layer (homogeneous and monolotic) bottle wall for oxygen removal is described in European Patent Application EP 380,830 published August 8, 1990. This reference discloses bottle walls of OXBAR (suitable for producing bottles of beer according to the description). OXBAR is a blend of approximately 96% by weight of pure PET, approximately 4% by weight of MXD6 and a solution of C8-C10 cobalt carboxylates that have approximately 10% by weight of cobalt as expanded metal to provide approximately 50 ppm of cobalt in terms of the weight of the mixture. MEXD6 is a polyamide prepared from equimolar amounts of adotic acid and metaxylenediamine. In accordance with the reference, the presence of MXD6 not only serves as an oxygen scavenger but also enhances the ability of PET to retard the leakage of CO2 from the bottle cavity through the bottle walls. Bottles produced under this reference would have serious deficiencies including, but not limited to: (1) loss of recycling possibilities, (2) a higher cost because the entire bottle consists of an oxygen scavenger material, (3) not having the opportunity to use recycled PET because the homogeneous walls are in contact with the product bottling, (4) possible leaching of excess cobalt in the bottled product, (5) no means to adapt, in an efficient and economical way, the oxygen removal capacity of the bottle at the required shelf life, and (6) rapid deterioration of the oxygen removal capacity (even in the preformation phase) due to the aggressive attack of oxygen from the air directly on the middle oxygen scavenger. Although not described in the reference, applicants have speculated on the effectiveness of a bottle comprising an outer layer of PET, a middle layer of OXBAR, and an inner layer of PET. The cost (very thick layer of OXBAR needed to provide the necessary oxygen removal capacity) and the recycling issue would still be present in such an embodiment.

The only major drawback of using multilayer bottle walls is that more complex bottle manufacturing machinery is required to form the multiple layers. The advantages derived from the use of multilayer bottle walls far outweigh the unique advantage of a more simple processing associated with a homogeneous monolayer bottle wall. Characteristically, the bottle wall embodiments of this invention are three-layer, AB-C layer constructions. Layer A is the outer layer that makes up the outside of the bottle and is in contact with the outside air. Layer B is the oxygen scavenger layer. Layer C is the inner layer and defines the cavity of the bottle. Among the advantages of such a multilayer construction are: (1) the ability to use recycled PET in layer A, (2) the ability to dilute (within limits) the stripper layer, layer B, with recycled or virgin PET, to easily and economically adjust the oxygen permeation capacity zero with respect to the planned shelf life, (3) isolation of the packaged product (bottled) from the oxygen scavenger layer by way of layer C (layer C is normally virgin PET), (4) isolation of the oxygen scavenger layer from the oxygen in the air due to the presence of the outer layer A and (5) preservation of the recycling capacity, since the multilayer bottles of this embodiment of the invention are characteristically constituted by more 99.6% of PET and PET segments. Likewise, the use of a five-layer bottle wall of the A / B / A '/ B / A type was envisaged where A is PET, B is the eliminating layer (or layers) either net or diluted and A' is also PET, especially recycled PET.

Brief description of the drawings

Figure 1 is a cross-sectional view of the preferred wall construction of a multilayer bottle with zero oxygen permeation.

Figure 2 shows a graph of idealized oxygen permeation data for bottles of three different constructions.

Figure 3 shows a graph similar to that of figure 2, which relates the permeation rates of the oxygen with the useful life of storage of the bottle.

Figure 4 shows a graph with oxygen permeation data for bottles from Examples 1-6.

IS 2 147 998 T3

Figure 5 shows a graph with data confirming the ability of copolyesters to consume headspace oxygen even when used as layer B in an A / B / A or A / B / C bottle wall construction.

Figure 6 shows a graph with data similar to that of figure 5 and also shows the ability of oxygen scavenging copolyesters to deplete oxygen from the headspace even when used as layer B in the wall construction of bottle A / B / A or A / B / C.

Figure 7 shows a graph presenting data confirming the increased oxygen scavenging capacity of oxygen scavenging copolyesters when used in admixture with a diluent, such as layer B in an A / B / A bottle wall construction or A / B / C.

Detailed description of the preferred embodiments

For the purposes of this invention, it is useful to define bottles with practically zero and almost zero oxygen permeation. Bottles with practically zero oxygen permeation are bottles that do not allow the introduction of oxygen, measurable reliably, into the cavity of the bottle during the specific shelf life of the product under specific storage conditions. In the absence of a specific amount of oxygen permeation that can be tolerated by the product, practically zero oxygen permeation will be defined as a permeation of no more than 1 ppm (in terms of weight of the bottled product) in the product during the life Specific storage facility for the bottled product. In the absence of a specified shelf life, for the purposes of this invention, the shelf life shall be considered as a period of time characteristically on the order of 30 to 365 days, more specifically on the order of 60 to 360 days, and more. specifically not on the order of 60 to 180 days. Also, in the absence of specifically defined storage conditions, the specific storage conditions for the purposes of this invention are defined as ambient temperatures (from 4 ° C to 25 ° C). Bottles with almost zero oxygen permeation are bottles that delay the introduction of oxygen into the bottle cavity to levels equal to or less than the amount specified for the given application and / or for the specific duration of storage of the bottled product under conditions of specified storage. With respect to bottles with almost zero oxygen permeation, the shelf life or specific duration in storage will be of the order of approximately 30 days to 2 years and the specified storage conditions are the same as those previously defined with respect to bottles with oxygen permeability. practically nil.

In a general sense, this description comprises the combination of several elements of the invention in most of the embodiments in order to achieve bottles that have qualities and capacities of oxygen elimination as previously defined. It has been found that novel oxygen scavenging copolyester compositions can be readily adapted to make zero and near zero oxygen permeation multilayer bottles and containers using commercial manufacturing equipment. As such, one of the elements of the invention comprises the use of known equipment, apparatus and machinery, employed in multilayer bottle manufacturing processes in a process to produce the oxygen permeation resistant bottles of this invention. Another element of the invention relates to the use of the oxygen scavenged polyester compositions as a layer (or comprising at least one layer) of the multilayer bottle. Another element of the invention involves the simple but eloquent techniques described for adjusting the oxygen scavenging capacity of manufactured bottles to the planned application in the most economical way. Combinations of these elements of the invention serve to define the various embodiments of the new multilayer plastic bottles with zero oxygen permeation of this invention.

The size (volume) of the bottles with practically zero and almost zero oxygen permeation of this invention would be of the order of 0.03 liter to 4 liters. Lower volume bottles, with a capacity of approximately 0.03 liter, would be used, for example, to bottle individual (mixed) cocktails such as those frequently used by airlines. Larger volume bottles, with a capacity of approximately 4 liters, will be used, for example, to bottle wines such as, for example, "double magno" size. Medium sized bottles would be suitable for beer and numerous other oxygen sensitive products, as noted elsewhere in this specification. While the bottles of this invention are primarily intended for the storage of edible products, the bottles will also be suitable for use with most non-corrosive, oxygen-sensitive products capable of being stored at atmospheric temperatures and pressures. As an extreme case, for example, the bottles of this invention will not be suitable for storing liquid oxygen, not only because it is outside the range of pressures and temperatures useful for storage, but also because the liquid oxygen will consume all the removal capacity of the oxygen.

ES 2 147 998 T3 oxygen from the bottles in a very short period of time. To be economically feasible, the amount of material used in the bottles of this invention should be of the order of magnitude of that used in traditional polyester bottles. The amount of material is directly related to the total wall thickness of the bottles and will usually be on the order of 0.1-2 mm (4-80 thousandths of an inch). Therefore, this invention describes a thermoplastic container with practically zero oxygen permeation for storing an edible product with a volume of the order of 0.03 - 4 liters and a multilayer wall with a total thickness of the order of 0.1 - 2 mm. . The containers and bottles of this invention may further comprise a base which may optionally be of monolotic construction and may also optionally be thicker than the walls, as a means of providing oxygen barrier properties of the non-layered base. The containers and bottles of this invention may further comprise an appropriate segment for the attachment of a sealing device or bottle cap. This segment may optionally be of monolotic construction and may also optionally be thicker than the walls, as a means of providing oxygen barrier properties to the non-layered segment.

In another preferred embodiment, this invention describes a near-zero oxygen permeation thermoplastic bottle having an edible product storage cavity, the bottle comprising a base that defines the bottom of the bottle cavity and a generally multi-layered side wall. cylindrical, attached to the base and extending away from the base, forming the wall of the bottle cavity and providing the necessary volume to the bottle cavity, said side wall ending to define an opening in the upper part of the bottle cavity suitable for the placement of a bottle cap or capsule , in which an inner layer of the side wall was made up of a copolyether formulation, scavenger of oxygen, which predominantly comprises polyether segments and a number of oxygen-scavenging polyolefin oligomeric segments, and whose bottle, after filling and capping, has sufficient oxygen-scavenging capacity: (a) to consume and deplete oxygen within the bottle cavity, (b) to consume and deplete oxygen that could penetrate through the opening of the bottle cap, and (c) to consume oxygen at approximately the same rate that the speed with which the oxygen from the air reaches the internal elimination layer, in which bottle the almost complete oxygen consumption, according to sections (a), (b) and (c), it is maintained at at least an oxygen depletion level necessary for a specific duration of the bottled product in storage under specific storage conditions.

In another embodiment, this invention describes a process for producing a multilayer bottle with oxygen removal, comprising the steps of:

(i) forming a first resin layer using a multilayer bottle making apparatus;

(ii) forming a second resin layer using a multilayer bottle making apparatus;

(iii) forming a third resin layer using a multilayer bottle making apparatus; and (iv) transforming the first, second, and third resin layers into a finished multilayer bottle using the multilayer bottle making apparatus;

which apparatus has means (A) for separately processing at least two different resins and (B) for forming a layered bottle having at least three layers, and in which at least one of the bottle layers comprises an oxygen scavenging copolyether resin formulation predominantly comprising polyether segments and an oxygen scavenging amount of polyolefin oligomoeric segments.

Preferred embodiments relate not only to the packaging of articles, but also to processes for making the articles, compositions used to produce the articles, and methods for economically adjusting the oxygen removal capacity of the articles. In such cases, it is most convenient for the purposes of this specification to describe the elements of the invention in sequence: (I) the multilayer bottle manufacturing processes comprised by this invention, (II) the copolyether compositions, oxygen scavengers, contemplated for use in at least one of the bottle layers, and (III) the various techniques and embodiments to adjust, in the most economical way, the oxygen removal capacity of the bottles adapted to the planned application.

1. Equipment and methods for the manufacture of multilayer bottles

In all cases, the layer comprising the oxygen scavenging copolyether compositions would be an inner layer of the bottle. As far as this description is concerned, an inner layer is defined

ES 2 147 998 T3 as an inner layer of the bottle wall. An inner layer is not a layer that is directly in contact with air. Also, an inner layer is not a layer that defines the cavity of the bottle and, in such case, it is not a layer in contact with the contents of the bottle. In most embodiments of this invention, three layers will be preferable.

The term "coextrusion multilayer blow molding" refers to a technique for manufacturing a blow molded product using two or more extrusion apparatus and introducing the hot molten resins into a mold and joining them in a die or die. out of the die. In the simplest terms, it is only necessary to join auxiliary extrusion apparatus and the multi-layer die to a traditional blow molding machine. Coextrusion of the same materials (resins) presents very few, if any, problems. However, there are many difficulties involved in molding bottles by coextrusion of different resins. Some of these difficulties include: (1) thermal decomposition of less stable resins, (2) poor moldability, (3) insufficient bond strength between layers, (4) poor fusion in narrowing or thinning sections due to different melting temperature and rheological characteristics different from cast resins, and (5) delamination due to different contraction forces between the layers after molding and during cooling after hot filling of the bottles. Of these, the biggest problem is poor adhesion between the layers.

A characteristic formulation, used as a layer in multilayer bottles with oxygen elimination, comprises a copolyether comprising 96% by weight of PET segments and 4% by weight of oligomeric polybutadiene (PBD) segments. This characteristic formulation is optionally coextruded with PET diluent as a middle layer on the wall of the bottle characteristically sandwiched between two layers of PET. PET resin and PET / PBD copolymer resin are virtually identical except for the small percentage of PBD segments. As such, they also have very similar properties and many of the problems noted above with respect to coextrusion of dissimilar resins do not arise when PET and PET / PBD copolymer are coextruded for multilayer bottle production. Consequently, for use in the production of multilayer bottles, procedures and equipment that lack some or many of the special features described in the embodiments that follow are appropriate when one of the layers comprises an oxygen scavenging copolyether formulation of this invention. . Naturally, for production batches, the manufacture of the multilayer bottles of this invention can take place in multilayer bottle production equipment of the current state of the art that is already being used, although the processes of manufacturing bottles with PET layers / remover copolyether / PET may be suitable for much less sophisticated bottle making equipment, particularly as regards the reduced need to separately control the temperature of the resins during injection molding of bottles and bottle parisons. The bottle manufacturing equipment, including the production of bottle parisons, comprising means for the separate injection of two different resins to produce multilayer bottles or bottle parisons operating at approximately the same temperature of both resins, comprises an embodiment general of this invention, provided that one of the resins is an oxygen scavenging copolyether resin formulation of this invention.

IA realization

Coextruded Multi-Layer Blow Molded Bottles (co-injected or sequentially injected resins) Including the Use of Bottle Parisones.

A process featuring simultaneous injection is described in US Patent 4,717,324 (Schad et al.). A primary feature of the Schad et al. Patent is to provide individual hot sprue systems for each resin from the resin source to the mold cavity, independently maintained and controlled at the optimum temperature for the treatment of the chosen resin. Another feature is to provide a nozzle structure, constructed and arranged to provide individual channels to each resin with individual heating means to maintain each channel at a temperature that is most satisfactory for the resin advancing through the channel. Also described is the use of a plurality of molding cavities that are simultaneously filled with each type of resin producing a plurality of multilayer articles simultaneously. This method is especially suitable for the production of three- and five-layer bottle parisons that comprise an inner layer (or layers) of EVOH always sandwiched between layers of PET. For this invention, applicants employ oxygen scavenging copolyether layers instead of EVOH layers or in addition to bone.

A process of injection in sequence or simultaneous for multilayer bottles is described in the Patent of

ES 2 147 998 T3 the US 5.41.695 (Yoshinori Nakamura). The Nakamura patent describes the production of bottomed five- and four-layer parisons using up to three different resins from a single nozzle having three flow passages. The parisons are then made into hollow containers by blow molding or orientation molding. Nakamura lists many resins that are appropriate for forming the layers on the blown bottle, including PET with EVOH. For this invention, the applicants employ layers of oxygen scavenging copolyester instead of layers of EVOH with PET or in addition to the same.

Another example of a sequence injection process for the formation of multilayer bottle parisons is described in US Patent 4,710,118 (Krishnakumar et al.). Krishnakumar's patent contemplates the production of five-layer bottles by forming parisons of five-layer bottles having layers consisting of ABCBA resins. Layers A and C can be the same and are usually PET. In some embodiments, layer C can be recycled and / or recovered bottling polyester. Layers B are typically EVOH and are typically much thinner than they will be in constructions having a single EVOH layer. The two thin layers of EVOH have better barrier properties than a single thick layer of EVOH. The Krishnakumar et al. Patent also describes new manifold and valve systems that provide separate control of each injected layer and also separate control of the temperature of the feed manifolds. As regards this invention, the applicants employ layers of oxygen scavenging copolyester instead of layers of EVOH with PET or additionally.

With regard to multilayer bottles comprising oxygen scavenger copolyester layers, processes in which the scavenger copolyester layer is not centered on the bottle wall between two PET layers of equal thickness are especially preferable. The walls of these bottles and the parisons of the bottles can be designed comprising layers of A1-B-A2 resin. Layer A1 is PET or other polyester for bottle manufacturing and is the layer that constitutes the outer surface of the bottle. The polyesters in layer A1 can be virgin, recycled, recovered polyesters, or mixtures of the foregoing. Layer A2 is also in PET or other polyester for bottle manufacturing and is the layer that defines the cavity of the bottle. Layer B is the oxygen scavenging copolyester. Generally, the thickness of the PET layer A1 will be on the order of 2 to 10 times greater than the thickness of the PET layer A2. This type of structure offers the oxygen scavenger copolyester layer a good opportunity to deplete the undesirable oxygen in the bottle cavity since the oxygen only has to pass through the very thin A2 layer of PET to reach the scavenger layer. where it is consumed. On the contrary, the oxygen from the outside of the bottle has to pass through the much thicker layer A2 of PET before reaching the scavenger layer and being consumed. In such a case, the thicker PET layer, towards the outside of the bottles, helps to prevent the introduction of oxygen to the scavenger layer, thus extending the useful life of the scavenger. Such a bottle and bottle parisoan construction is described in US Patent 4,990,301 (Krishnakumar et al.). The Krishnakumar '301 patent describes the use of layers of EVOH (centered and off-center) sandwiched between layers of PET. Likewise, the '301 patent describes the use of multiple conduit coaxial nozzles and feed means to separately feed different resins to the nozzle conduits, allowing separate and simultaneous injection of different resins into the mold of the tubes. bottle parisons. The use of PET outer layers and EVOH inner layers is described. With respect to this invention, applicants employ scavenger copolyester layers instead of EVOH layers with PET or additionally.

An injection molding apparatus, including similar coinjection modules, each provided with common feed systems and fed with different resin materials at intermediate pressures by a plurality of extruders, is described in US Patent 5,028. .226 (De'ath and others). In the De'ath et al. Patent, each resin is injected by an injector directly into the corresponding nozzle and is controlled exclusively by operation of the injector and without the use of any regulation valve between the injector and the nozzle. This process can be adapted to form up to seven layers in the parisoan but typically five layers and only two or three resins are used. With respect to this invention, the applicants employ an ABCBA layer construction, where A and C are PET layers and at least one of the B layers is made up of an oxygen scavenging copolyester composition.

An injection molding process, where the parisoan of the multilayer bottle is held in an upright position during manufacture, is described in US Patent 4,957,682 (Kobayashi et al.). The Kobayasi patent describes the production of three-layer containers and parisons, that is, a bottle wall having ABA layers. A key difference is that the injections are sequential and delays between resin injections are described. In a characteristic process of the Kobayashi patent:

(1) the outer resin layer A is injected, (2) after a delay of up to three seconds,

ES 2 147 998 T3 middle layer B is injected, and (3) after another delay that reaches up to one second, second layer A is injected. Sequence injection with delays provides improved uniformity of layer B. The resins described are PET (layers A) and EVOH (layer B). As regards this invention, the applicants employ oxygen scavenging copolyether layers as layer B instead of EVOH layers with PET or additionally generally constituting layers A.

A process for producing multilayer bottle parisons using a hot sprue mold for multilayer molding, which includes a plurality of nozzle bodies for injecting a plurality of different resins for the formation of a multilayer product, is described in the US Patent No. the US 5,232,710 (Miyazawa et al.). The hot sprue mold comprises a plurality of hot sprue blocks each having a sprue for conducting each resin to the corresponding resin body. The hot sprue blocks are stacked on top of each other with layers of thermal insulation placed between the stacked sprue blocks. Each hot sprue block has a separate temperature control to keep each resin at the optimum brewing temperature. Three-layer bottles of PET-EVOH-PET resin are typically produced. With respect to this invention, the applicants employ oxygen scavenging copolyether layers instead of EVOH layers with PET layers or additionally.

Realization IB

Overlapping / Lamination Molding Process for the Preparation of Bottles and Multilayer Bottles Parisones

The published PCT application, having the international publication number WO 95/00325 and publication date of January 5, 1995, characteristically describes a three-layer PET-EVOH-PET bottle and bottle parison. The outer layer of PET is made up of PET from consumers (recycled). The inner layer of PET, which defines the cavity of the bottle and was in contact with the contents of the bottle, is virgin PET. The EVOH layer can be omitted when there is no need to impart oxygen barrier properties to the multilayer container. An annular flange, in the virgin PET layer, is formed with the mold at the end of the parisoon that receives the bottle closure device (eg, the open end of the parisoon). The flange extends sufficiently outward such that the cap operculum contacts only virgin PET while the cap threads fit over the threads formed in the recycled PET layer. The inner virgin PET layer is therefore molded over the outer recycled PET layer. With regard to this invention, applicants employ oxygen scavenging copolyether layers instead of EVOH layers with PET layers additionally.

Japanese Patent Document JP 3,275,327, published December 6, 1991, discloses a laminated blow molded container for hot beverages comprising a PET laminated construction which also features a PET base and high heat resistant resin. thermal deformation temperature. The laminated blow molded container consisted of a mouth, a shoulder, a body and a bottom. The body is made of PET. The bottom consisted of a laminated structure of PET and a heat resistant resin having a temperature of thermal deformation above 100 C. Preferably, the body and the base include a layer of oxygen barrier resin, for example EVOH, on the bottom. laminated structure. The heat resistant resin is, for example, an aromaotic polyether such as PEN. The beverage container is especially useful for hot fill applications since the thermal deformation that occurs in hot fill of traditional multilayer bottles is eliminated. With respect to this invention, the applicants employ oxygen scavenging copolyether layers instead of EVOH layers with PET and / or PEN layers or additionally.

A multilayer plastic container with improved gas barrier properties using an active oxygen scavenger (or adsorption layer) of resin is described in US Patent No. 4,107,362 (Emery I. Valyi). Some of the layers are formed using superposition molding technology rather than coinjection or sequential injection to form the bottle or bottle parision layers. Rather, two layers of plastic are placed around a core contained within a mold that subsequently expands into a blow-molding container. Finally, a third layer is press molded around the two layer sleeve. The result is a seamless multilayer plastic container. The container is three-layered and embodiments featuring the adsorbent in the inner layer are described, in addition to embodiments featuring the adsorbent in the middle layer. The adsorbent material, which is capable of combining with undesirable permeation gas, is an additive to the layer of plastic in which it resides. With regard to this invention, the applicants employ oxygen scavenging copolyester layers as the middle layer in a three layer embodiment.

ES 2 147 998 T3 instead of the middle layer containing the adsorbent or based on polyether, or in addition to it.

IC realization

Improved Processes for Bottle Production

A method for making bottles having highly crystalline bottle walls with a poorly crystalline bottle base is described in US Patent 5,520,877 (Collette et al.). According to their discovery, Collette et al. Bottles are particularly useful as a refillable container that can withstand higher chaoustic wash temperatures and produce reduced flavor transmission. Also, based on the description, Collette et al. Bottles are also useful for hot fill applications. The bottle is formed from a single layer composed of PET from a layer in which a section of the layer, which constitutes the side wall, is initially expanded, heated to contract and crystallize, and then re-expanded. The portion that forms the base of the parison is protected from the skin treatment and expands either before or after the skin treatment operation. With respect to this invention, only the hot fill ability feature is exploited and the single layer of PET is replaced by a three-layer construction of PET / scavenger copolyether / PET.

Another process for the production of hot fill plastic bottles is described in US Patent 5,474,735 (Krishnakumar et al.). The Krishnakumar et al. '735 patent discloses a method and apparatus for forming a plastics container that has an improved level of crystallinity for increased thermic stability. A substantially amorphous and transparent parison in the molecular orientation temperature range is expanded by a pulse blowing process, one or more times, to form an intermediate article, before the final stage of expansion to full dimensions of the container. The pulse blowing phase is carried out at a relatively high strain rate to maximize the formation of crystalline nucleation sites, followed by deflation to relax the amorphous orientation, and the final expansion phase is performed at a low rate of deformation to reduce the amorphous orientation to the mononym. The resulting container has a higher thermal deformation temperature and low thermal contraction and is particularly adapted for use as a hot fill beverage container. A blow mold and fluid feeding apparatus is provided, including a metering chamber and piston to alternately provide high and low strain rate inflations. With respect to this invention, Applicants employ a three-layer PET / scavenger copolyether / PET construction for the bottle walls instead of a single-layer polyester bottle wall.

A method for the production of handle bottles is described in US Patent 5,533,881 (Collette et al.). The '881 patent to Collette et al. Describes a process and apparatus for producing a blow molded container from a deformation-hardenable polymer. The container has deep recesses for the attachment of a "post-mold" handle. The container is formed in a modified blow mold having retroactive plates. The plates are partially extended to mold partial recesses and then extended to mechanically form the deep recesses for the handles. The mechanical forming operation solves the stretch limits imposed by the deformation hardening of the plastic material during blow molding, and the “post-mold” handle joint provides reduced cycle time and a lower level of defects compared to known "in-mold" handle forming operations. As far as this invention is concerned, Applicants employ a three-layer PET / scavenger copolyester / PET construction for the bottle walls instead of a bottle wall and a single layer of polyester.

A process for forming a three and / or five layer bottle parison is described in US Patent 5,032,341 (Krishnakumar et al.). The '341 patent to Krishnakumar et al. Describes a plastics parison from which a plastic container is blow molded. The parison replaces a three-layer parison by providing a parison that is of a five-layer construction in the portion that constitutes its base and in which a secondary material, which constitutes the core layer of the three-layer parison construction, is Divided into an inner intermediate layer and an outer intermediate layer by a third injection of material. The third material injected is preferably the same material as the primary material that is injected first. This results in a reduction in the cost of the parison and also provides, while remaining in the injection nozzle, an amount of the last injected material that is the same as the first material injected for the next parison into the same cavity of the injection mold of the parison. The bottle parison is a three-layer ABA type parison where the last part of the B layer is filled with less expensive material C, such that the base constitutes the five-layer part (ABCBA) while the walls are made of three layers (ABA). This serves

ES 2 147 998 T3 to reduce the amount of B-layer material at the bottom of the bottle and therefore reduces the overall cost of the container. With respect to this invention, Layer A is a bottle polyester, for example PET, Layer B is an oxygen scavenging copolyether resin formulation, and Layer C is a less expensive substance than Layer B, for example, recycled / recovered polyester for bottles or polyester for bottles.

Made ID

Techniques That Minimize Delamination

A vented barrier multilayer container is described in US Patent 4,979,631 (Collette et al.). The '631 patent to Collette et al. Discloses blow molded plastic containers in which at least the body of such containers is of laminate construction including, for example, a barrier layer which, when it is a container for products carboenics, it would be a gas barrier layer. It has been found that delamination of such bottles occurs and that it is now solved by selectively providing the body of the container with tiny ventilation openings that do not entirely pass through the body of the container, but rather reach the area where delamination occurs, in the which is likely the accumulation of a permeant, for example CO2 from carbonated beverages contained in the cavity of the bottle. Tiny ventilation holes can be formed in the outer wall of the container by means of piercing tips or by using a laser. When it comes to piercing tips, the tips are incorporated into the blow mold used to blow mold the container from a parison and are generally located along the dividing lines of the blow mold and also in the central parts. of the wall. The construction and operation of piercing tips can be provided in a variety of ways. Delamination is not a problem in three-layer walled bottles comprising PET / scavenger copolyether / PET using characteristic copolyester formulations, due to the similarity of properties of the two resins. However, the use of oxygen scavenging copolyether, which is heavily loaded with oligomeric polyolefin segments (for example, more than 12% by weight of the copolyether is derived from oligomeric polyolefin segments) represents cases in which applicants will make use of special techniques to minimize delamination, such as tiny vents, as described in this embodiment.

Other techniques for minimizing delamination, such as the use of adhesives, are well known in the industry. Another method of producing multilayer parisons that resist delamination involves cooling the parison while it is still on the core. In this embodiment, the nuclei and parisons are removed from the molding cavities as soon as possible without considerable physical deformation of the parisons. The parisons are then cooled on the nuclei for a convenient period of time that prevents delamination of the layers of the parisons. The cooling of the parisons outside the molding cavities is also faster and allows faster cycle times when means, for example a rotating turret, are available for the use of multiple cores. Applicants contemplate the use of adhesive or the cooling of the parisons in those cases where the bottles produced benefit from such additional treatment.

II. Oxygen Scavenging Copolyether Formulations

As noted above, oxygen scavenging compositions are block copolycondensates containing predominantly polycondensate segments and an oxygen scavenging amount of oligomeric polyolefin segments. By "predominantly" it is meant that at least 50% by weight of the copolycondensate can be attributed to segments of the polycondensate. Preferred polycondensate segments, especially for use in bottle production, are the polyester segments. With respect to layers in multilayer bottles in which some of the layers are PET and / or PEN, segments of the block copolyether comprising PET and / or PEN are especially preferred. A major reason is that oxygen scavenging copolyesters more accurately emulate the polyester from which their polyester segments are derived. PET and PEN are the polyesters of choice for bottles due to their transparency, rigidity and long history of use for storage of food and beverage products. The use of polyesters other than PET and / or PEN for the A layers in a bottle construction of ABC layers (A is the outer layer) will justify the use of polyester segments derived from the polyester of layer A in the formulation of the copolyether. layer B of the bottle. Frequently, layers A and C of an ABC layer bottle construction are the same, except that layer A can be recycled polyester, since it is isolated from the contents of the bottle cavity. The oligomeric polyolefin segments of the copolyether are the moieties responsible for the oxygen scavenging capacity.

IS 2 147 998 T3

While we do not pretend to be bound by any theory, the applicants subscribe to the school of opinion that believes that the mechanism of adsorption of oxygen in hydrocarbon materials, such as polyolefin oligoomers, is done by fixation of oxygen on the hydrocarbon material by formation. of hydroxy groups or of hydroperoxy groups. It is further believed that these groups are formed through a free radical process involving an intermediate peroxy moiety. In a hydrocarbon substance, carbon atoms that have only one bound hydrogen (a so-called tertiary hydrogen, are more susceptible to free radical formation than are carbon atoms that have two bound hydrogens (so-called secondary hydrogens) which, in turn. Instead, they are more susceptible to free radical formation than carbon atoms with three linked hydrogen atoms. Applicants further believe that alolic hydrogen atoms (hydrogen atoms bonded to a carbon atom adjacent to a double bond) are also subject to free radical formation. Applicants have recognized that hydrocarbons such as polyolefins, especially polydienes, constitute a potentially suitable source of secondary and tertiary hydrogens in addition to allolically activated hydrogen atoms. The applicants then devised methods for incorporating these oxygen scavenging hydrocarbon moieties into polyesters for the production of bottles by copolyether formation using end-functionalized polyolefin oligoomers. Oxygen scavenging copolyether systems and compositions are fully described in co-pending US Application No. 08 / 717,370, filed September 23, 1996.

Polyolefin oligomoeric segments (of the block copolyethers that comprise the formulations used in bottle layers) are prepared by copolycondensation by first functionalizing the polyolefin oligomeric segments with end groups capable of entering polycondensation reactions. This is an important and novel feature of these formulations because the polyolefin oligoomers are, in fact, segments of addition polymers incorporated in a polycondensate. The functionalization of end-group polyolefin oligoomers provides a convenient method for incorporation of additive polymer segments and a polycondensate. Many end groups can enter polycondensation reactions, but the preferred end groups are hydroxy (-OH) and carboxy (-COOH) because the use of such end groups results in a copolyether that has all the polyether bonds in between. polyether segments and oligomeric polyolefin segments. For example, end amino groups (-NH2) are very acceptable but do result in the formation of some polyamide-like bonds in the vicinity of the polyolefin oligomeric segments of the copolyether. Those skilled in the art will recognize that some or all of the hydrogens on the end groups can be substituted for other moieties and still give rise to the same copolyether structure.

A preferred polyolefin oligoomer is polybutadiene (PBD) because it has good oxygen scavenging ability and reacts rapidly with oxygen especially in the presence of a transition metal catalyst, for example cobalt. Most preferably it is a polybutadiene oligoomer with dihydroxy termination functionality in the 1000 to 3000 molecular weight range because it produces a highly transparent copolyether when incorporated into a block copolycondensate having predominantly PET, PEN, or other polyether segments. for bottle production and also because it is commercially available in the necessary form and purity. Copolyomers produced with polyolefin oligomers of molecular weight on the order of 1000 to 3000 have a transparency above 70% of the transparency of the unmodified polyester from which their polyester segments are derived. The oligomomeric polyolefin segments are responsible for the oxygen scavenging capacity of the oxygen-tin scavenging copolyether systems present only to the extent necessary to provide the desired oxygen scavenging capacity. Polyolefin oligomeric segments typically represent less than 50% by weight of the polycondensate, with a preferred weight percent range of polyolefin oligomeric segments on the order of 2 to 12% by weight of the polycondensate. Copolyethers comprising 2 to 12% by weight of polybutadiene segments, the remainder of the weight comprising PET, PEN, and / or other polyether segments for bottle production, including PETB, PETG, and APET, are especially preferred due to the high transparency of these copolyethers, because they are easily biaxially oriented, and because they have vitreous transition temperatures well above ambient temperature (storage or ambient). PETG is modified PET in which up to about 40 mole% of the polyethylene glycol (as monomer) is replaced by an equivalent mole percent of cyclohexane substituted with hydroxymethyl groups at the 1,4- or or 1,3- positions on the cyclohexane ring. APET is amorphous PET marketed by Eastman. PETB is modified PET in which up to about 40 mole% of the terephthalic acid is replaced by 4,4'-dicarboxybiphenyl. Those skilled in the art will understand that additional oxygen scavengers, catalysts (e.g. cobalt) and other additives can be used in conjunction with the copolyether oxygen scavenger in order to optimize the removal of

ES 2 147 998 T3 oxygen and / or other properties. Scavenger copolyesters can be prepared by direct polycondensation processes including the desired amount of hydroxy-terminated polyolefin oligeomer and maintaining an equivalent amount of dihydroxy monoemer (eg, ethylene glycol) from the direct polycondensation process. The applicants have determined that the preferred way to carry out this invention is to prepare the copolyether formulations by transesterification in a reactive extruder (instead of direct polycondensation) using as raw materials a polyester for the production of bottles (eg PET) and Dihydroxy-terminated PBD. Embodiments in which the scavenger copolyester is prepared in situ, simultaneously with the bottle production process, or otherwise as part of the bottle production process, are also within the scope of the invention.

The scavenger copolymer compositions, referenced as Embodiments II-A through II-J, as listed in Table 1 below, were all prepared on an experimental facility scale in the manner described herein. A ZSK-30 extruder was equipped with a PET pellet feeder with loss in weight under a nitrogen atmosphere. The hydroxy-terminated PBD was kept in a viscous fluid container from which it was transported separately, via a volumetric pump to a vacuum suction port in the extrusion line. The PET (Shell Clear Tuf® 7207) was extruded at a feed rate of approximately 8 pounds (3.6 kg) per hour providing a residence time of approximately 4 minutes, while maintaining the temperature in the range of 260 to 270 ° C. The hydroxy-terminated PBD (Elf Atochem RLM20 - 1230 molecular weight or RHT45 - 2800 molecular weight) was pumped into the extruder at variable speeds to provide weight percentages on the order of 2% to 12% relative to the hydroxy-terminated polybutadiene in the mixing zone of the extruder. Melt sealing designs were used to create a vacuum zone following the mixing zone before the die opening. The extrudates were anhydrous and did not emit fumes and easily granulated after quenching in a water bath. In the water bath, no surface film (oily film) could be observed, indicative of copolymer formation by transesterification during reactive extrusion. The appearance of a film in the water bath would have indicated the presence of unreacted polyolefin oligomer. Cobalt octoate (Hulls Nuodex® DMR 6% cobalt) at a treatment rate sufficient to provide 50 PPM Co when the hydroxy-terminal PBD was used at 2% by weight, and 200 PPM Co when the hydroxy-terminal PBD was used at 8% by weight. All scavenger copolymers, prepared by the method described above, had unique glass transition temperatures (Tg) of the order of 62.0 ° C to 72.9 ° C. The copolymers prepared by the above-described method were suitable for melt processing and capable of being bottle and / or layered into multilayer bottles in accordance with the preferred three-layer bottle wall embodiment of this invention. In applications that require copolyesters of higher intrinsic viscosity (IV), techniques that improve the molecular weight can be used. For example, preparation of the copolyether by direct polycondensation (rather than transesterification) leads to much higher molecular weights for the copolyether. Alternatively, melt rheology modifiers could be added to the copolyester prepared by transesterification to achieve a high molecular weight for the copolyester.

The copolyether compositions referenced as Embodiments II-K to II-N, as listed in Table 1 below, were also prepared by reactive extrusion in a ZSK-30 twin screw extruder. First, PET granules (Shell Tray Tul '' 1006) were dried in a desiccant oven at 125 ° C for a minimum of 8 hours. The granules were then introduced into the feed section of the extruder via a weight loss feeder under nitrogen gas atmosphere. Low molecular weight (about 1230 mw) viscous polybutadiene diol (R20LM from Elf Atochem) was placed in a pressure vessel and pressurized with nitrogen gas. The liquid was then brought separately into the PET melt through an injection port in the extruder by way of a volumetric pump. The feed rate of the PET was set at approximately 14.4 pounds / hour (6.48 kg / hour) while the PBD diol was fed at a rate of approximately 0.6 pounds / hour (0.37 kg / hour). . The residence time employed was approximately 4 minutes which allowed the copolymerization to be completed in the extruder. The temperature profile of the reaction was kept in the range of 250-270 ° C.

IS 2 147 998 T3

TABLE 1

Eliminating Copolyester Formulations

<td>Realization</td><td>% wt PBD</td><td>P. Mole. PBD</td><td>Polyester</td><td>Comments</td>

<td>II-A</td><td> 2</td><td> 1230</td><td>PET</td><td></td>

<td>II-B</td><td> 4</td><td> 1230</td><td>PET</td><td></td>

<td>II-C</td><td> 4</td><td> 2800</td><td>PET</td><td></td>

<td>II-D</td><td> 4</td><td> 1230</td><td>PET</td><td>150 ppm Cobalt added</td>

<td>II-E</td><td> 4</td><td> 2800</td><td>PET</td><td>150 ppm Cobalt added</td>

<td>II-F</td><td> 6</td><td> 1230</td><td>PET</td><td></td>

<td>II-G</td><td> 8</td><td> 1230</td><td>PET</td><td></td>

<td>II-H</td><td> 8</td><td> 2800</td><td>PET</td><td></td>

<td>II-I</td><td> 10</td><td> 1230</td><td>PET</td><td></td>

<td>II-J</td><td> 12</td><td> 1230</td><td>PET</td><td></td>

<td>II-K</td><td> 4</td><td> 1230</td><td>PET</td><td>0.2 to 0.3% by weight of pyromelotic dianhydride (PMDA) added to the formulation</td>

<td>II-L</td><td> 4</td><td> 1230</td><td>PETI</td><td>PETI is modified PET in which part of the terephthalic acid is replaced by isophthalic acid</td>

<td>II-M</td><td> 4</td><td> 1230</td><td>PETN</td><td>PETN is modified PET in which part of the terephthalic acid is replaced by a naphthalene dicarboxylic acid</td>

<td>II-N</td><td> 4</td><td> 1230</td><td>PEN</td><td></td>

The volatiles generated from the reaction were removed through an open port of the extruder by means of a vacuum pump. The copolyether extrudate was cooled and granulated. The finished granules were packaged in a moisture and gas resistant aluminum foil pouch. To keep the product free from oxygen contamination, the entire extrusion chain was protected with a nitrogen atmosphere (including discharge cleaning of the storage bags).

PMDA was added to the II-K embodiment as a chain extender that served to raise the molecular weight of the copolyether and therefore raise the intronsic viscosity (IV) of the copolyethers. For example, the IV of the 4% wt PBD PET copolyether (± 1320) (embodiment II-B) was 0.57, which was still suitable for use in bottle production. The addition of 0.2% by weight of PMDA raised the IV to 0.71 while the addition of 0.3% by weight of PMDA raised the IV to 0.74.

IS 2 147 998 T3

Such materials can match in viscosity to that of neat PET (eg Shell 7207 PET has a nominal IV of 0.72).

For beer bottles, it is necessary to eliminate, or at least minimize, the loss of carbon dioxide (CO2) through the walls of the bottle. Applicants' tests have produced results demonstrating that modified PET, where part of the terephthalic acid monomer has been replaced by isophthalic acid (or equivalent derivatives) and / or where part of the terephthalic acid has been replaced by naphthalene dicarboxylic acid (or equivalent derivatives), produces a bottle polyester that has superior barrier properties to CO2 permeation. The PETIs and PETNs in Table 1 are representative of such formulations. As such, appropriately modified PET is typically used for beer bottles in order to improve the CO2 barrier properties of the bottle. Especially preferred are combinations and / or mixtures of PETI and PETN. For maximum CO2 barrier effect, similarly modified PET can also be used as the source of the polyester segments in the oxygen scavenging copolyester and can also be used as a diluent in the oxygen scavenging layer of the bottle.

III. Zero oxygen permeation optimization

Another innovative element in this general invention has to do with the various means described for adjusting the elimination capacity to levels of oxygen permeation practically null or almost null, depending on the application. The means described are not only diverse, but can also be carried out with great ease, in various cases, with fine adjustment of the eliminating capacity up to the moment of the manufacture of the bottles and in another case until the filling of the bottle. bottles. Of course, it is possible to use more oxygen scavenger and / or thicker scavenger layers. However, one aim is to achieve the required degree of oxygen scavenging capacity needed in the most economical manner in order to produce commercially viable bottles. Once the degree of oxygen scavenging has been determined, the methods of adjusting the oxygen scavenging capacity and / or the usable storage life with practically zero / near zero oxygen permeation required of the bottle can be carried out by means of one or a combination of several of the embodiments that will be described below.

Relationship III-A

Molecular Weight of PBD Segments in the Eliminator Copolyether

The variation of the molecular weight of the PBD segments, used in the manufacture of the oxygen scavenging copolyester, is a technique to adjust the oxygen scavenging capacity of the copolyester, as described in the original jointly pending application filed on 23 of September 1996 and which has the application number 08 / 717.370. In that application, Examples 12 and 14 were copolyether formulations comprising 4% PBD segments and 96% PET segments. Example 12 (having a PBD of ± 2800) was a much more effective oxygen scavenger than Example 14 (having a PBD of ± 1230) at room temperature and in the absence of cobalt catalyst. The variation of the oxygen scavenging capacity or useful life in storage using this technique is probably the most retrospective of all those described, in the sense that a decision must be made before the manufacture of the copolyester oxygen scavenger system.

Realization III-B% by Weight of PBD Segments in the Eliminating Copolyether

Variation of the weight percent of PBD segments in copolyether formulations is another technique that is also described in the original co-pending application filed September 23, 1996 and having application number 08 / 717,370. This series of related applications comprises and contemplates copolyasters comprising up to 50% by weight of PBD segments, the remainder comprising polyester segments. Table 1 above presents formulations of polyesters scavenger compositions having 2, 4, 6, 8, 10 and 12% by weight of PBD segments. Table 2 below presents data confirming that those compositions having a higher percentage of PBD segments also have a higher oxygen scavenging capacity. The data in Table 2 were taken by the method of Examples 12 to 15 of the co-pending original application number 08 / 717,370.

IS 2 147 998 T3

TABLE 2

Oxygen Removal Capacity of Various Copolyester Formulations (data taken at 22 C - 150 ppm cobalt catalyst was used)

<td>% by weight of PBD segments in copolyester</td><td> 0</td><td> 2</td><td> 4</td><td> 6</td><td> 8</td><td> 10</td>

<td>O adsorption₂ after 70 days cc / gram copolyester)</td><td> 0</td><td> 5,17</td><td> 10,35</td><td> 15,49</td><td> 19,28</td><td> 20,13</td>

The variation of the oxygen removal capacity or useful storage life by this technique is also a relatively retrospective method of those described in this specification in the sense that a decision must be made at the time of the eliminator copolyester manufacture.

Realization III-C

Simultaneous Use of Other Oxygen Scavengers with Eliminating Copolyester Inside Bottle Walls

In FIG. 1, layer 30 represents the middle oxygen scavenging layer of the multilayer bottle wall construction of this invention. While this stripper layer may comprise, in some embodiments, about 100% stripper copolyether, applicants have found advantage in the deployment of dilute copolyether. In this case, for a reason, it more easily allows a uniform distribution of the scavenger system over the entire wall of the bottle. The diluent is characteristically the polyester of the outer layer 26 of the bottle wall or the inner layer 28 of the bottle wall in Figure 1. In most cases, the polyester of layers 26 and 28 is the same except that the polyester in layer 26 can be entirely or partially recycled material. Any diluent used in layer 30 can also be entirely or partially recycled material.

Another advantage of the dilution of layer 30 is that the technique lends itself perfectly to the preparation in advance of the formulation to be used as layer 30 and also to the preparation in advance of simple and / or plural concentrates that constituted layer 30 when manufactured. the bottle. The advance formulation of layer 30 or concentrates thereof allows to simplify the inclusion of additional oxygen scavengers in the layer that would be available for oxygen scavenging simultaneously with the oxygen scavenging copolyether of layer 30. Preferred are photoactive materials which remain inert toward oxygen adsorption during bottle storage until sufficiently UV irradiated to activate them for this purpose and thus the oxygen adsorption rate is improved. An especially preferred photoactive scavenger is benzophenone. When used, benzophenone displays in the range of 50-500 ppm based on the weight of the oxygen scavenging copolymer layer. In general, the activating irradiation was administered immediately prior to shipping or use (filling) of the manufactured bottles.

III-D relationship

Degree of Dilution of the Copolyether in the Oxygen Eliminating Layer

As indicated in III-C above, most embodiments involve the addition of diluent to the oxygen scavenging copolyester layer of the multilayer bottles. The degree of dilution of the copolyether in the scavenger layer serves as another effective method for adjusting the oxygen scavenging capacity of the bottle. Characteristically, the diluent comprises from zero to about 95% by weight of the stripper layer. In various extreme embodiments, diluent has been deployed in excess of 99% by weight. The diluent is characteristically PET, virgin or recycled, but could be any low cost compatible material. As such, diluting the copolyether to only the level required for the given application can significantly reduce the cost of the bottle.

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Realization III-E

Degree of Decentralized Disposition of the Oxygen Scavenger Layer

Especially preferred for multilayer bottles comprising oxygen scavenger copolyeoster layers are those embodiments in which the scavenger layer of the bottle is not centered on the bottle wall between two PET layers of equal thickness. This statement can be better understood by referring to Figure 1. Layer 26, which is the outer PET layer of the bottle that constitutes the exterior of the bottle 24, is substantially thicker than layer 28, which is the inner PET layer of the bottle that constitutes the interior of the bottle 22 In practice, the thickness of the outer PET layer 26 will normally be on the order of about the same thickness to about 10 times the thickness of the inner PET layer 28. For any given total thickness (that is, the sum of layer 26 and layer 28 is constant), the degree of decentration plays an important role in determining the oxygen removal capacity and the useful storage life of the cells. bottles. When the outer layer of PET is thick, less oxygen is introduced to the scavenger layer and therefore the useful storage life is extended for oxygen consumption from this source. When the inner layer of PET is thin, more oxygen could permeate from inside the bottle (oxygen from the headspace or from other sources, such as introduction through the closure device or cap) to the eliminator layer through through the inner PET layer. Therefore, a thin, inner layer of PET provides faster and more complete depletion or depletion of the oxygen present within the bottle cavity. In typical embodiments, the stripper layer (30 in Figure 1), including the diluent if any, characteristically comprises about 10% by weight of the total weight of the bottle, and the stripper copolyester in that layer may comprise about 0 5 to about 10% by weight of the bottle depending on the degree of dilution. Characteristically, the scavenger copolyether unfolds with about 4% by weight of PBD segments in the copolyether. In such a case, the bottles of this invention have on the order of 99.6 to 99.98% by weight of polyether and polyether segments and, more characteristically, about 99.2% by weight of polyether and polyether segments.

Those skilled in the art will understand that the oxygen scavenging capacity and / or the useful shelf life of a bottle could be adjusted by varying the thickness of the inner PET layer only (28 in Figure 1) or only the PET layer. external (26 in figure 1). These inner and outer PET layers can be individually and independently varied. There is no need to maintain a constant sum over the thicknesses of the two bonded layers, except for comparison purposes to maintain a given amount of PET per bottle and / or to determine the optimal arrangement of the middle layer. While a thick outer layer of PET might appear favorable, economic considerations will generally serve to limit the thickness of the outer PET layer and, in a corresponding way, the amount of PET used in the bottle.

Realization III-F

Use of Oxygen Scavenging Catalysts

Examples 23 to 26, in co-pending application number 08 / 717,370, clearly indicate that the oxygen scavenging efficiency of copolyethers can be greatly improved in the presence of a transitional metal catalyst such as cobalt. Consequently, the deployment (or lack of deployment) of a catalyst, as well as the degree of deployment, represents another method of implementation to control the oxygen scavenging capacity and useful storage life of the bottles of this invention. The preferred transition metal catalyst is cobalt because its effect on the efficiency of the removal copolyether is most prominent. Cobalt characteristically unfolds in the form of a cobalt carboxylate. Cobalt octoate is preferable because it is effective at lower levels of unfolding and is also commercially available in an appropriate solvent and state of purity. Characteristically, cobalt displays in the range of 50 to 300 ppm in terms of the weight of the copolyether or (as will be explained in more detail later) 50 to 300 ppm in terms of the combined weight of the copolyether plus the diluent used in the coating layer. bottle oxygen scavenging copolyether.

The bottles of this invention are characteristically three-layer and only PET (not the oxygen scavenger layer) is in direct contact with the bottled product. Most of the glasses used to make glass bottles contain some cobalt that can work its way into bottled beer. Cobalt is also found in PET as a trace catalyst left over from the cobalt catalyzed polymerization of PET. Several decades ago, it was a

It is common practice to add small amounts of cobalt to beer to improve and maintain foam stability. Characteristically, cobalt is present in bottled beer to a degree of 0.1 mg / L which was approximately the limit of detection several decades ago. The beer, to which cobalt was added for foam stability, had approximately 1.0 mg / L cobalt. More recently, in the mid-1980s, evidence began to emerge indicating that the presence of cobalt could induce cardiomyopathies in some beer drinkers. Only heavy beer drinkers, who were also exposed to massive amounts of cobalt in their occupations, put their health at risk. In spite of everything, the voluntary addition of cobalt to beer was abandoned around this time.

The PET / MXD6 single-layer bottle, described above, brings the bottled beer into direct contact with the PET / MEXD6 blend that also comprises 50 ppm cobalt and creates the possibility of cobalt catalyst leaching from the brewing material. bottle to beer. In the multilayer bottles of this invention, the beer was in direct contact only with the inner PET layer (as with any beverage in a PET bottle) and was not in contact with the cobalt catalyzed oxygen scavenger layer. A control test was carried out and it was found that, after 28 days of storage at an accelerated test temperature of 120 ° F (approximately 50 ° C) in a bottle of layer B with 10% by weight of copolyester (100 ppm Co in layer B), the beer bottled in the same demonstrated to contain approximately 0.17 mg / l of Co which accurately equates to the control beer from a glass bottle, stored in a similar way, which was shown to contain approximately 0.086 mg / l of cobalt.

In an attempt to determine the optimal (minimum) charge of cobalt catalyst for effective oxygen removal in layer B, which would meet the required removal and shelf life requirements after dilution of layer B with PET, Applicants came to the surprising observation that dilution of the copolyester in layer B actually increased the effectiveness of the layer as an oxygen scavenger on a unit weight basis. Stated otherwise, in the presence of a constant and sufficient cobalt catalyst% by weight, one gram of oxygen scavenging copolyester can be up to 30% more effective when used in quadruple dilution on films. A fourfold dilution in the polyether layer in finished bottle compositions doubled the removal capacity over a period of 84 days and was a 50% improvement over a period of 168 days. While we do not wish to be bound by theory, we applicants believe that the copolyester (present in the stripping layer) acted as an attractive element for cobalt. As such the utilization of sufficient cobalt (for catalyzing purposes) is limited to where it is needed (in the copolyester) regardless of the amount deployed, within the limits of use of this invention. Applicants further believe that this property is due to the display of cobalt catalysts in the form of an aliphatic moiety. Therefore, the preferred catalysts are aliphatic cobalt carboxylates. Cobalt octoate is especially preferred because it exhibits these properties, causes the copolyester to behave optimally toward oxygen adsorption, and also because it is commercially available in the solvent, concentration, and state of purity necessary for embodiments of this invention. In conducting the experiments that led to the discovery that diluted copolyester has a higher killing capacity, the applicants observed that the downside of this effect is the introduction of a longer induction period before the copolyester reaches its potential. total elimination.

Realization III-G

Simultaneous Use of Oxygen Capsule Capsules with Oxygen Removal

Seguín previously indicated, a possible source of oxygen infiltration in beer bottles is found through the material of the bottle capsule cover. The use of a bottle capsule cover with oxygen scavenging capabilities provides a good defense against this possible source of oxygen contamination. Likewise, an oxygen scavenging bottle capsule cover may be employed to provide additional scavenging capacity to remove oxygen from the headspace since the capsule cover is in direct contact with the headspace in the bottle. Such bottle capsule covers may be comprised of the copolyester oxygen scavengers of this invention which have the ability to scavenge oxygen under dry and humid conditions. However, the environment of the tapíerculo allows the use of other scavengers that have scavenging ability exclusively in the presence of moisture, for example iron-based oxygen scavengers. A bottle capsule cover comprising an iron-based oxygen scavenger is described in US Patent No. 4,840,240. The optional use and quantity of oxygen scavengers in the bottle capsule cover represents another embodiment to control the oxygen scavenging capacity and / or the useful shelf life of the bottles.

ES 2 147 998 T3 multilayer of this invention. The preferred bottle capsule covers for this invention contain the oxygen scavenger between the outer layer (metal or plastic) of the bottle capsule and an inner cover that is permeable to oxygen (and also permeable to water vapor as far as possible). refers to iron-based scavengers). The permeable inner liner serves to isolate the oxygen scavenger from the bottled product while allowing oxygen from the headspace to reach the scavenger and thus be consumed. Such bottle caps comprising a metal or plastic outer layer, an oxygen permeable inner liner / layer and oxygen scavenger in between, can be manufactured in advance and stored (in a reduced oxygen environment if necessary) to be ready for use. for immediate use when the bottles are filled. In such a case, the use of an oxygen scavenging bottle cap cover allows final adjustment of the oxygen scavenging capacity and / or the shelf life until the bottle filling process.

Performed III-H

Use of Plural Oxygen Scavenging Layers

While most of this description has been directed to bottles having only a single oxygen scavenging layer on the bottle wall, the use of plural oxygen scavenging layers is also contemplated. For example, a five-layer bottle wall of construction A / B1 / A '/ B2 / A (where A is PET, B1 is the outer scavenger layer, and A' is virgin or recycled PET, and B2 is the inner scavenger layer. ) offers a good opportunity to use recycled PET. This embodiment also produces a construction in which layer B1 can be optimized to remove permeating oxygen from outside the bottle, and layer B can be optimized to remove oxygen from inside the bottle cavity.

Relationship of oxygen permeation rate to useful storage life

It is intuitively evident that there is a relationship between the rate of oxygen infiltration into the bottle cavity under specific storage conditions and the shelf life of the bottled product. In the preceding section of this description various means are described for conveniently and economically adjusting the oxygen permeation rates to the level required to ensure the required shelf life of the bottled product. Taking Figures 2 and 3 as reference, it may be helpful to better understand the relationship of oxygen permeation rates to useful storage life. Figure 2 represents ideal data that could be developed for an oxygen permeation model for plastic bottles. Figure 2 is a graph showing the oxygen permeation rates (in any convenient units of volume per unit air of the bottle wall) on the Y axis. The X axis indicates time. All data correspond to bottles having a given total wall thickness (general). With respect to an actual typical bottle of the invention, the typical total wall thickness would be on the order of about 10 to 25 thousandths of an inch (0.25 to 0.625 mm). The permeation rate line for a bottle having a PET wall is constant since PET has a fixed O2 permeation rate under a given set of conditions. The permeation rate line corresponding to a bottle that has a PET / EVOH / PET wall is also constant, but always less than PET, since the proportion of EVOH layer of the wall of the bottle of fixed thickness is a O2 barrier, passive, lower than PET. The situation corresponding to a bottle having a PET / scavenger copolyester / PET wall is depicted at several different levels of diluent for the middle scavenging copolyether layer, as described in the previous section (III-D). Because copolyether is such an outstanding O2 scavenger, it can consume oxygen faster than it permeates through the outer PET layer of the bottle. This characteristic of the copolyether may be present even at high levels of diluent. For the purposes of this description only, it is shown that complete oxygen depletion ceases to exist at diluent levels greater than the moderate level indicated in Figure 2. In a similar way, higher diluent levels prove to be more permeable to O2 and is consistent with the description set forth in section III-D above using the amount of diluent to regulate the O2 removal capacity (also speed and duration). bottle storage tool). In Figure 2, it is indicated that the copolyether bottles initially have a rate of permeation approximately the same as that of PET bottles due to a period of activation (delay) before the elimination capacity of the copolyester reaches its potential. total elimination of O2. Such a delay is relatively unimportant and can be easily resolved by a variety of techniques. An easy means of overcoming the lag is to make the bottle in advance and then store the bottle for several days (during the activation period) prior to filling. The scavenger copolyether curves finally reach the level of PET after the

ES 2 147 998 T3 elimination of the copolyether.

The amount of oxygen that reaches the bottle by permeation through the wall of the bottle is equal to the permeation rate (Y axis in figure 2) multiplied by the duration of such permeation rate (X axis in figure 2 ). Thus, the amount of oxygen that reaches the bottle by permeation through the wall of the bottle is the area under the curve with respect to any of the three curves in Figure 2. For a given application (bottled product) its tolerance to the presence of oxygen is normally given as a maximum amount of oxygen intake in the bottle cavity. The tolerance of the product to oxygen can be given in a relative way, for example parts per million, but such data is easily converted into a maximum amount of oxygen based on the size of the bottle or the weight of the bottled product. Figure 3 presents areas under the curves similar to the curves in Figure 2. The area under each curve is the same and is equal to the maximum tolerance to oxygen of a given product for each of the three curves. Continuing with the reference to figure 3, this figure shows how the useful life in storage corresponding to each type of bottle is easily determined once the maximum tolerance to oxygen (area under each curve) has been represented on the axes.

Examples

Bottle Manufacturing

Twelve ounce bottles (433 cc capacity, 31.1 g weight) were manufactured on a Nissel 250 TH single stage injection lamination blow molding machine. Only one side of the double-sided machine was used. A more complete description of the Nissel 250TH machine can be found in US Patent No.^°. 5,141,695 cited above. The 24 mm diameter side spindle A of the unit was calculated to contain 16 charges for the molding apparatus used. The B-side screw, with a compression ratio of 2.4 to 1, was estimated to contain 16 charges when layer B of an ABA bottle construction was specified for 10% by weight of the total parison. Conditions were established using PET Shell 5900 as a test layer B, because its viscosity is similar to that of the scavenger copolyether comprising about 96% by weight of PET and about 4% by weight of PBD. The copolyether formation (PET with 4% by weight of PBD) was diluted with PET so that the scavenger polyester constituted 25 to 100% by weight of layer B. The catalyst, when present, was used in a ratio of 100 ppm of cobalt, and the benzophenone, when it was present, was used in a ratio of 100 ppm, with respect to the total weight of layer B (that is, copolyether plus diluent). Cobalt and benzophenone were fed to the apparatus as pre-prepared concentrated granules mixed with the active layer filler.

A specific example of the process conditions employed is described as follows. The Layer A extruder was charged with PET Shell grade 7207. The Layer B extruder was used to melt an anhydrous blended mixture of the following granules:

a) 97 parts of PET scavenger copolyether and 4% by weight of PBD (Embodiment II-B);

b) 2 parts of accelerator blue which is a cobalt concentrate at 0.5% by weight, as an octoate salt, in PET;

c) a part of white accelerator which is a 1.0% by weight benzophenone concentrate in PET.

The concentrates from b) and c) above were prepared by melt blending the appropriate amounts of each component in a twin screw extruder and collecting the granulated products. The A-side (layer) extruder barrel temperatures, from the feed throat to the nozzle, were adjusted as follows: 265, 265, 265, and 265^°C. The temperatures of the corresponding B-side (layer) were 250, 250, 270 and 260^°C. The hot sprue blocks were all set to 270^°Cyla mold temperature at --- 10 C. Total cycle time was approximately 32 seconds / part. Microscopic analysis of the composition of the bottle indicated that the thickness of the B layer equaled approximately 11% of the bottle wall (10% was the target). The thickness of the three layers varied according to the position along the bottle, being thicker near the neck or neck and thinner near the bottom of the closed end. Adjustments to the process or sequencing settings will be evident to those skilled in the art who wish to obtain a different distribution of the thickness of the three layers.

IS 2 147 998 T3

Examples 1-6

I made a series of bottles (indicated as Examples 1-6) having a total side wall thickness of approximately 20 thousandths of an inch (0.5 mm), a weight of approximately 31 grams each, with an appropriate volume to hold approximately 12 ounces of beverage, and a three-layer (A / B / C) bottle wall construction. In each of the example bottles, outer layer A (PET) had a thickness of approximately 15 thousandths of an inch (0.375 mm), layer B (stripper layer) a thickness of approximately 2 thousandths of an inch (0.05 mm) and the inner layer C (PET) a thickness of approximately 3 thousandths of an inch (0.075 mm). In each of Examples 1-6, the scavenger copolyether employed comprised about 4% by weight of PM 12340 PBD segments and about 96% by weight of polyester segments. Table 3 that follows further characterizes the composition of the middle scavenger layer (B) of each example.

The oxygen permeation data, taken for the bottles of Examples 1-6, is presented graphically in Figure 4. The data was taken by purging all the air from the bottles of Examples 1-6 with nitrogen. Oxygen permeability was measured using a MOCON Oxtran test unit operating at room temperature (approximately 22 ° C) over a period of several days. The results (Figure 4) demonstrated a gradual improvement in the oxygen barrier properties of the scavenger copolyether bottles over time. After a copolyether activation period of approximately 3 weeks, bottles with sufficient oxygen scavenging capacity (for example, at least 50% by weight of copolyether or more in middle layer B) and with cobalt present at approximately 100 ppm, had perfect oxygen barrier properties, that is, zero oxygen permeation. Perfect performance was maintained for more than 120 days with no indication of zero oxygen permeability deviation when the test was terminated after approximately 300 days.

TABLE 3

Three Layer Oxygen Scavenger Bottles Examples 1-6

<td>Example No.</td><td>Resin Composition Layer B (Layer B is approx. 10% of the weight of the bottle)</td><td>Cobalt in layer B (ppm)</td><td>Benzophenone in layer B (ppm)</td>

<td> 1</td><td>100% PET (control)</td><td> 0</td><td> 0</td>

<td> 2</td><td>25% by weight copolyester 75% by weight PET thinner</td><td> 100</td><td> 100</td>

<td> 3</td><td>50% by weight copolyester 50% by weight PET diluent</td><td> 0</td><td> 0</td>

<td> 4</td><td>50% by weight copolyester 50% by weight PET diluent</td><td> 100</td><td> 0</td>

<td> 5</td><td>50% by weight copolyester 50% by weight PET diluent</td><td> 0</td><td> 100</td>

<td> 6</td><td>100% by weight copolyester 0% by weight PET diluent</td><td> 100</td><td> 100</td>

The bottles that had a lower percentage of copolyether in the middle layer B (that is, 25% by weight as in Example 2) provided insufficient oxygen scavenging capacity to achieve zero oxygen permeability, but reached a steady state value. permanent low (permeation almost zero). It should be noted that the X-axis of the graph in figure 4 is graduated in oxygen cc keys of days per bottle, so that minor errors and / or false readings appear as exaggerated deviations.

IS 2 147 998 T3

Examples 7-14

The bottles of Examples 7-14, another series of bottles, were subjected to a different procedure. Each of these cylinders will be filled with a gas containing 2% by weight of oxygen, as a method to simulate the presence of oxygen in the headspace, and then sealed in a gas-tight manner by adhesive bonding to the cylinders. plates of latoan provided with septa. This will be interpreted as a serious condition in the oxygen headspace since the total content of the bottle was 2% oxygen by weight, not just the small space above the liquid as is the case with a full bottle. The weight% oxygen in this series of bottles was monitored over a period of several days using a MOCON Oxtran test unit at 22 ° C and 100% relative humidity. All bottles of Examples 7-14 contained 100 ppm cobalt and 100 ppm benzophenone in layer B. The bottles of Examples 7-14 were further characterized in Table 4.

The data corresponding to Examples 7-14 is plotted in Figure 5 and demonstrates (except with respect to Control Examples 7 and 8 that had no scavenger copolyether in layer B) that oxygen is consumed from inside the cell cavity. the bottle. The data in Figure 5 were taken at 22 C and 100% relative humidity. The data corresponding to Examples 7-14 are also represented graphically in Figure 6. The data in Figure 6 were taken at 60 ^ C and 0% relative humidity. Again the data show that oxygen is consumed from inside the bottle cavity by the action of the scavenger copolyester in layer B.

TABLE 4

Three Layer Eliminator Bottle Examples 7-14

<td>Example No.</td><td>Layer B Resin Composition (Layer B is approx. 10% of the weight of the bottle)</td><td>Uv Applied</td>

<td> 7</td><td>100% PET</td><td>YES</td>

<td> 8</td><td>100% PET</td><td>NOT</td>

<td> 9</td><td>100% by weight copolyester 0% by weight PET diluent</td><td>YES</td>

<td> 10</td><td>100% by weight copolyester 0% by weight PET diluent</td><td>NOT</td>

<td> 11</td><td>50% by weight copolyester 50% by weight PET diluent</td><td>YES</td>

<td> 12</td><td>50% by weight copolyester 50% by weight PET diluent</td><td>NOT</td>

<td> 13</td><td>25% by weight copolyester 75% eh weight thinner PET</td><td>YES</td>

<td> 14</td><td>25% by weight copolyester 75% by weight PET thinner</td><td>NOT</td>

Examples 15-18

Seguín previously indicated, it was observed that the dilution of the eliminating copolyester with a diluent,

ES 2 147 998 T3 for example PET, caused the oxygen removal capacity to increase when described on a weight per unit copolyether basis. The data in Examples 15-18 serve to demonstrate this effect. The copolyether films of Examples 15-18 all comprised 4% by weight of PBD segments with the remainder of the copolymer comprising polyether segments. With respect to all Examples 15-18, 100 ppm benzophenone and 100 ppm cobalt were also used. The ppm value of benzophenone and cobalt refers to the total weight of the film, that is, copolyether scavenger plus diluent. The films are further characterized in Table 5 below.

TABLE 5

Copolyether Films Remover Examples 15-18

<td>Example No.</td><td>wt% copolyester</td><td>% by weight diluent</td><td>Benzophenone ppm</td><td>Cobalt ppm</td>

<td> 15</td><td> 100</td><td> 0</td><td> 100</td><td> 100</td>

<td> 16</td><td> 75</td><td> 25</td><td> 100</td><td> 100</td>

<td> 17</td><td> 50</td><td> 50</td><td> 100</td><td> 100</td>

<td> 18</td><td> 25</td><td> 75</td><td> 100</td><td> 100</td>

The oxygen removal capacity of the four films of Examples 15-18 was determined using a method similar to that of Examples 12-15 of U.S. Application No. 08 / 717,370 filed September 23, 1996. 5 gram film samples were used and a desiccant was placed in each of the 500 cc jars to create and maintain a 0% relative humidity environment. The results are graphically presented in Figure 7. As will become apparent from Figure 7, the scavenger copolyether has a higher oxygen scavenging capacity (in terms of amount removed per unit weight of copolyether when used mixed with diluent as layer B in a bottle wall construction A / B /TO).

The specification and examples of this invention have extensively described processes for the manufacture of multilayer bottles with oxygen removal. Those of ordinary skill in the art will recognize that a wide variety of other containers such as glasses, bowls, trays, would benefit from the application of this invention and should be considered incorporated within the scope of the invention. Likewise, the effectiveness of the scavenger copolyether at 0% relative humidity (see Examples 15-18) shows that it is an effective oxygen scavenger even in a dry environment, making it suitable for applications in such an environment, for example, for packaging. of electronic components sensitive to oxygen.