HIGH-Tg COATING FILM

The present invention generally relates to coatings for plastic and glass articles. More specifically, the present invention relates to phenoxy-based coatings for articles (eg, premolds and bottles) with improved chemical resistance, abrasion resistance and heat resistance.

Laminates, such as gas barrier materials, i.e., multi-layer premolds and containers having at least one layer of material having a gas permeability smaller than that of the substrate are known. For example, US Pat. No. 5,472,753 (Farha) discloses two- and three-layer laminates such as premolds and bottles. In the disclosed three-layer laminate, the first layer is a phenoxy-type thermoplastic, the second layer is an amorphous thermoplastic copolyester, and the third layer is polyethylene terephthalate. In a two-layer laminate, the first layer is a blend of a phenoxy-type thermoplastic and an amorphous thermoplastic copolyester, and the second layer is polyethylene terephthalate (PET). The disclosed phenoxy-type thermoplastic substances include poly (hydroxy ethers), poly (hydroxy ester ethers), and poly (hydroxy amino ethers), and preferred amorphous thermoplastic polyesters are poly (1,4). -Cyclohexyline methylene) terephthalate-co-isophthalate, which is formed by partially exchanging ethylene glycol and terephthalic acid in PET with cyclohexanedimethanol and isophthalic acid, respectively. Also, for the purposes of the disclosed invention, PET is a PET homopolymer, and ethylene glycol up to about 10 mol% is other monomeric units (eg, diethylene glycol, propane-1,3-diol, butane-1). , 4-diol, polytetramethylene glycol, polyethylene glycol, polypropylene glycol, 1,4-hydroxymethylcyclohexane, etc., and up to about 10 mol% of terephthalic acid is other monomeric units (eg, isophthalic acid, bibenzoin). Acid (bibenzoic acid), naphthalene 1,4- or 2,6-dicarboxylic acid, adipic acid, sebacic acid, decane-1, Refers to a copolymer of ethylene terephthalate that has been exchanged with 10-dicarboxylic acid, etc.). For premolds and containers, the inner layer is preferably the PET layer.

U.S. Pat. Nos. 6,312,641 and 6,391,408 and U.S. Patent Application Publication No. 10 / 152,318 (Hutchinson et al.) Have good gas barrier properties, such as bottles and premolds containing one or more layers of thermoplastic material. Disclosure of plastic articles and methods for producing such articles. The disclosed plastic article is formed from a thermoplastic polyester on which a barrier layer is applied. Preferred thermoplastic polyesters are PET, but other thermoplastic polyesters, namely polyethylene 2,6- and 1,5-naphthalates (PEN), PETG, polyethylene 1,2-dioxybenzoate, and ethylene terephthalate. Copolymers with ethylene isophthalate are also disclosed. Copolyesters of terephthalic acid, isophthalic acid and at least one diol are excluded as substrate materials as they are considered barrier materials for the purposes of the present invention. The barrier layer is a copolyester barrier material, i.e. terephthalic acid, a copolyester of isophthalic acid with at least one diol, and a phenoxy type thermoplastic material, i.e., hydroxy functionalized poly (amide ether), poly (hydroxyamide ether). ), Hydroxy-functionalized polyethers, hydroxy-functionalized poly (ether sulfonamides), poly (hydroxyester ethers), hydroxy-phenoxy ether polymers, and poly (hydroxyamino ethers) (PHAE). Formed from either. In addition to the various injection molding techniques disclosed, it is also disclosed to apply the barrier coating layer using various immersion coating methods, spray coating methods and flow coating methods.

As will be appreciated by those skilled in the art, forming multiple layers on an article may be desirable in some applications, but whatever method is used to form the layers, the manufacturing process of the article It is complicated and typically costly. Therefore, if possible, it is desirable for economic reasons to limit the number of layers in the article. As a result, materials such as gas barriers that have not been approved by the FDA for contact with food, especially in premolds and containers intended for consumables, are preferably doubled as an outer and protective layer of the article. Has the role of.

It is desirable that the outer layers of the glass article and the plastic article have various characteristics. First, especially for containers such as bottles and jars that are exposed to the environment of the filling line, the outer layer of the container preferably has good wear and chemical resistance, physical wear and corrosion. The article is resistant to the filling line environment where the bottle is exposed to lubricants and beverages or other container components that can cause the bottle. In addition, the coating material is preferably compatible (ie miscible) with various colorants such as pigments and UV blockers, and for spray coating methods, dip coating methods and sink coating methods, the coating material is a colorant or Form a stable dispersion with UV blockers.

In addition, the glass transition temperature of the coating on the thermoplastic premold intended for injection molding into the heat-filled vessel T_gShould be relatively high, as the premold is placed in a blow molding mold with a temperature of about 140 ° C during blow molding. As a result, a relatively low T_gOuter layer with (eg, T in the range of about 50 ° C to about 70 ° C)_gPHAE material) tends to be sticky to the inner surface of the injection mold. Therefore, a relatively low T_gThe use of these materials can result in unacceptable imperfections, mold damage and production line outages during the manufacture of the final product.

It has been found that cross-linking the coating material improves its chemical resistance and abrasion resistance. However, high levels of cross-linking cannot be introduced into the coating of the premold because the fully crosslinked thermosetting material does not stretch during the injection molding process. Moreover, low levels of cross-linking do not significantly increase the chemical and abrasion resistance of the coating. In addition, a relatively low T_gThe problems associated with blowing molding the material into a heat-filled vessel remain unsolved.

In some applications, it may be desirable to blend ultraviolet (UV) blockers, pigments or other additives to the coating. Therefore, as mentioned above, the compatibility between the additive and the coating composition is important in such applications. However, as disclosed by Hutchinson et al. In dip coating, spray and flow coating methods, UV blockers and pigments are incompatible with dispersions of PHAE materials and the PHAE materials sufficiently wet the additives. Since it is absent, it quickly precipitates from the dispersion.<patcit num="1"><text>U.S. Pat. No. 5,472,753</text></patcit><patcit num="2"><text>U.S. Pat. No. 6,312,641</text></patcit><patcit num="3"><text>U.S. Pat. No. 6,391,408</text></patcit><patcit num="4"><text>U.S. Patent Application Publication No. 10 / 152,318</text></patcit>

<p> Therefore, chemical resistance and abrasion resistance, T_g, As well as the need for coating compositions with low gas permeability of PHAE materials with improved compatibility with pigments and UV blockers. The present invention provides such a composition.</p>

<p> The present invention provides novel coating methods for articles, articles coated using the methods of the invention, coating compositions for use in the methods of the invention, and coated articles that overcome the shortcomings of prior art. To do. The method of the present invention has a T of at least about 75 ° C, preferably about 75 ° C to about 110 ° C._gHave a high T_gThe step of applying the phenoxy-type material to at least a part of the surface of the article and the high T on the surface of the article._gIncludes the step of forming a dried / cured coating containing a phenoxy-type material. Above high T_gCoatings containing phenoxy-type materials further include PHAE and / or the above high T._gArticle surfaces coated with a phenoxy-type material include a coating containing PHAE. The coating composition applied is preferably high T_gIt is a dispersion containing a phenoxy-type material, and this dispersion may further contain PHAE. The dispersion of the phenoxy-type material is preferred in the present invention, but a solution of the material may also be used.</p><p> The coating composition, which comprises at least one phenoxy-type material and is preferably a dispersion, may further comprise at least one additive, such as a UV blocker, pigment, or metallized pigment. Some additives are incompatible with PHAE, resulting in high T dispersion_gIn the absence of additional phenoxy-type materials, these additives precipitate from the additives and dispersions containing PHAE. In contrast, such additives have a high T_gIt is compatible with dispersions containing phenoxy-type materials and therefore no additives are precipitated even if the dispersion contains PHAE. If the additive is incompatible with the PHAE dispersion, the additive is preferably high T._gHigh T before mixing phenoxy-type material with PHAE to form a dispersion_gBlended with phenoxy-type material.</p><p> High T_gCoating compositions containing phenoxy-type coating materials may be applied alone or in combination by dip coating, spray coating and flow coating, or high T on the article._gPhenoxy-type materials may be applied, preferably using the inject-over-inject method disclosed by Hutchinson. The covered article has a high T_gPrior to applying the phenoxy-molded material, it may be coated with a PHAE coating layer, for example by either overmolding, immersion coating, spray coating or flow coating, or high T._gThe phenoxy-type material and PHAE may be melt-blended in an extruder, for example, before the article is overmolded or dip coated, spray coated or flow coated. In addition, such melt blends are used to prepare dispersions of resins and may be applied by dip coating, spray coating or sink coating.</p><p> In the application in which the coating composition according to the present invention contains two kinds of resins, the first resin has a high T._gIt is a phenoxy type material, and the second resin is preferably a PHAE material. Preferably, in such a blend of resins, the two resins have a phenoxy-type material vs. PHAE of about 10:90 to about 50:50, more preferably about 20 based on the total weight of the two resins. It exists in a weight ratio of: 80 to about 40:60. The composition may be one of two resin dispersions suitable for dip coating, spray coating or flow coating, or a melt blend of two resins suitable for overmolding.</p><p> The coated article according to the present invention comprises an article substrate having a surface and a T of at least about 75 ° C._gHave a high T_gA coating layer having a phenoxy-type material on at least a part of the surface of the article is provided. Above high T_gThe coating layer containing the phenoxy-type material may further contain PHAE, and / or the coating layer containing PHAE has a high T._gIt may be arranged between the coating layers including the phenoxy type material and the surface of the article substrate.</p>

As used herein, with respect to such materials or resins, the term "phenoxy" refers to polyhydroxyethers having an alpha glycol group at the end. Skeletal ether bonds and branched hydroxyl groups promote wettability and binding to polar substrates and fillers. A typical phenoxy-type resin has a weight average molecular weight in the range of about 25,000 to over 60,000. The average phenoxy-type resin molecule contains 40 or more regularly spaced branched hydroxyl groups suitable for cross-linking.

As used herein, the term "polyhydroxyamino ether" ("PHAE") refers to epoxy-based resins such as diglycidyl ether of bisphenol A ("DGEBA") and primary amines such as ethanolamine. Refers to the reaction product with. Branched hydroxyl groups on the main backbone of PHAE are thought to contribute to strong intermolecular hydrogen bonds, high intermolecular aggregation energy densities, and excellent barrier properties against gases such as oxygen and carbon dioxide. The literature shows that further improvements to the PHAE barrier can be obtained by copolymerizing resorcinol diglycidyl ether (RDGE) with the components described above. In addition, RDGE-based PHAE copolymers are considered within the definition of PHAE for the purposes of this disclosure.

As used herein, the term "high T"_g"Phenoxy-type material" refers to a thermoplastic phenoxy-type material having a glass transition temperature of at least about 75 ° C, preferably about 75 ° C to about 100 ° C. High T useful in the present invention_gPhenoxy-type material has a significantly higher T than PHAE_gHas significantly better chemical resistance, water resistance and abrasion resistance than PHAE.

In the present invention, the coating has low gas permeability of PHAE composition and high T._gHigh T provided by phenoxy type material_gComposition for coated articles (eg, thermoplastic premolds and containers, and glass articles), which have high chemical resistance and abrasion resistance, as well as high co-compatibility with additives (eg, UV blockers and pigments). Regarding things. Furthermore, the present invention relates to plastic articles and glass articles coated with the compositions of the present invention, and methods of coating such articles. Although the disclosure of the present invention relates specifically to coated thermoplastic premolds and containers, those skilled in the art have described the invention to any type of article, such as, but not limited to, coated glass articles such as bottles. And plastic preforms and containers, as well as other plastic articles).

Gas permeability of phenoxy type material is inferior to that of PHAE material, but high T_gPhenoxy-type materials have been found to have many advantages. Especially high T_gThe material has a higher T when compared to the PHAE material_gIt has excellent chemical resistance and abrasion resistance, has excellent wettability that gives compatibility with colored pigments, and has excellent compatibility and miscibility with UV blockers.

As mentioned above, relatively low T_gPHAE materials may not be compatible with heat injection molded and heat filled containers. T in the range of about 50 ° C to about 70 ° C, especially when used as the outer layer of premolds_gPHAE material with may stick to the mold after blow molding. In addition, such relatively low T when exposed to hot liquids during the heat filling operation._gMaterials can be damaged.

In addition, layers of PHAE material may be applied to the substrate by dipping, spraying or casting a dispersion of PHAE material, but the wettability of PHAE material is relatively small, pigments and UV. Many additives, such as blockers, precipitate from PHAE dispersions. As a result, PHAE-based coatings containing pigments and certain additives such as UV blockers are difficult to form from dispersions of PHAE, if not impossible.

In contrast to PHAE materials, T at at least about 75 ° C_gHave a high T_gPhenoxy type material has a higher T_gImproved adhesion to injection molds due to, and significantly better chemical resistance compared to PHAE material-based coatings when exposed to hot liquids and lubricants on the filling line. Was also found to have. In addition, high T_gThe abrasion resistance of the phenoxy type material is superior to that of the PHAE material without the need for cross-linking. However, if desired, any useful type of crosslinker known in the art, such as a melamine formaldehyde-based crosslinker, can be used as long as the coating material remains flexible for elongation during stretch injection molding. You may use it.

In addition, high T_gPhenoxy type material has high T_gIt may be applied to the substrate by dip coating, spray coating and / or flow coating on the substrate surface with a water-based dispersion of phenoxy-type material. But high T_gThe excellent wettability of phenoxy type materials is higher than that of PHAE materials with additives such as UV blockers and pigments._gIt was found that the compatibility with the phenoxy type material was significantly improved. As a result, additives that increase UV resistance and color the article or give the article other desired properties have a high T._gDoes not precipitate from dispersions of phenoxy-type materials. In particular, it has a significantly higher load and a higher T than when using PHAE material._gIt was found that the metallizing pigment can be dispersed in the phenoxy type material. This makes it possible to create a metallized texture on the surface of the base material.

The substrate is preferably a thermoplastic material, such as a thermoplastic polyester, ie PET and PEN, but PHAE and high T useful in the present invention._gA dispersion of phenoxy-type material may also be used to coat the glass substrate.

The methods of the invention are PHAE materials and high T_gProvided is an article with a coating that offers the advantages of both phenoxy-type materials. That is, the method of the present invention has a gas barrier property of PHAE material and has a high T._gRelatively high T of phenoxy type material_gProvides a coating layer that is chemical and abrasion resistant, as well as compatible with additives.

In one embodiment, the methods of the invention are dispersions of PHAE materials and high T._gIt includes a step of providing a dispersion of a phenoxy-type material and a step of blending two kinds of dispersions. Acids such as lactic acid or phosphoric acid may be added to stabilize the dispersion. A blend of the two dispersions is then applied to the substrate surface by dip coating, spray coating or flow coating. High T_gBecause the phenoxy-type material is compatible with additives that may give the final product one or more desired properties (eg, UV blockers, pigments and metallized pigments), the methods of the invention provide two dispersions. High T at least one useful additive before blending_gIt may further include the step of blending into the dispersion of the phenoxy type material.

In another preferred embodiment, PHAE and high T_gThe material is melt blended in an extruder. A dispersion of the blend is formed and applied to the surface of the substrate, or a melt blend is applied onto the substrate, eg, Inject-Over-Inject (IOI) and LIM-Over-In disclosed by Hutchinson. It may be overmolded by LIM-over-inject technology. It has been found that additives such as UV blockers and pigments may be blended with the melt blend or dispersed in the dispersion of the blend. High T_gThe presence of the phenoxy-type material provides the compatibility needed to form dispersions and / or suspensions containing one or more additives. Preferably, any additive is added to the dispersion prior to the addition of the PHAE material.

In a further embodiment, a single PHAE-based layer is formed on the substrate by dipping, spraying or casting a dispersion of PHAE onto the substrate surface, or by directly overmolding the resin. Will be done. High T with or without one or more additives_gThe layer containing the phenoxy type material is then applied to the PHAE coated surface by dip coating, spray coating or flow coating, or by directly overmolding the resin.

As a representative description of an article coated by the method of the invention and capable of preparing a coated article of the invention, an uncoated preform 1 is shown in FIG. Those skilled in the art will recognize that the present invention is not limited to pre-molded articles and containers made from pre-molded articles. Preferably, the premold 1 is formed from an FDA approved material, such as untreated PET, and can have any useful shape and size suitable for stretch-injection molding in a container. As will be appreciated by those skilled in the art, the inner surface of the premolded article for making containers containing food or beverage must be formed from FDA approved materials. As illustrated, Preform 1 is of the type used to form 16 ounce carbonated beverage bottles, which may be coated with an oxygen and / or carbon dioxide barrier layer. However, as will be appreciated by those skilled in the art, the size, shape and thickness of the premold will depend on the desired size, shape, thickness and use of the final article. Preferably, the premold is formed using injection molding techniques known in the art, but may be formed using any useful molding method that provides the desired premold.

A cross-sectional view of a typical uncoated preform 1 shown in FIG. 1 is shown in FIG. The uncoated premold 1 comprises a neck portion 2 and a body portion 4. The neck portion 2 defines an opening 18 inside the premold 1 and begins at the opening 18 and extends to the support ring 6 and includes the support ring 6. As shown in FIGS. 1 and 2, the neck portion 2 is further characterized by the presence of threads 8, which are means for fixing caps for bottles made from premold 1. I will provide a. However, as will be appreciated by those skilled in the art, any known means for fixing the cap or top to the container (eg, bottle) may be used. The body portion 4 is an extended, cylindrical shape structure extending downward from the neck portion 2, has an outer surface 14, and ends with a circular end cap 10. The thickness 12 of the premold depends on the total length and wall thickness of the premold and the final size of the resulting container.

FIG. 3 is coated according to the present invention, not limited to, according to the representative invention, i.e., preferably high T._gBy dip coating, spray coating or flow coating with phenoxy-type materials and dispersions containing PHAE; first with dispersions containing PHAE, then high T_gBy dip coating, spray coating or sink coating with a dispersion containing a phenoxy-type material; PHAE resin, then high T_gBy overmolding the phenoxy type resin; or PHAE resin and high T_gFIG. 5 is a cross-sectional view of a premolded article 20 coated by overmolding with a blend of phenoxy-type resins. The coated premold 20 is essentially the premold shown in FIGS. 1 and 2, but is coated with the materials and methods of the invention. When the pre-molded article 1 shown in FIGS. 1 and 2 is used, the coated pre-molded article 20 includes a neck portion 2 and a body portion 4.

The coating layer 22 is preferably a barrier coating layer that adheres to the perimeter of the entire surface of the body portion 4 and ends at the bottom of the support ring 6. The coating layer 22 does not extend to the neck portion 2 and is not present on the inner surface 16 of the premold. The inner surface 16 of the premold is preferably manufactured from an FDA approved material, such as PET or PEN, as described above. The coating layer 22 may contain either a single material or some fine layers of at least two materials, at least one of the fine layers having a high T._gIncludes phenoxy-type material.

The final premold thickness 26 is equal to the sum of the initial premold thickness and the layer thickness 24 and depends on the final size of the resulting container and the desired coating thickness. For example, the premolded article according to the present invention has a thickness of 3.2 mm at the bottom wall of the premolded article, a final thickness of about 3 mm at the neck wall, and a thickness of about 0.3 mm at the barrier layer. May be good.

A further embodiment of a representative coated article according to the present invention (ie, the coated premold 21) is shown in cross section in FIG. The coated premold 21 differs from the coated premold 20 of FIG. 3 primarily in the relative thickness of the two layers in the region of the end cap 10. In the coated premold 20, the coating layer is generally thinner in the body portion of the premold as a whole than in the initial premold. However, in the coated premold 21, the coating layer 22 is thicker at point 29 in the end cap 10 than at point 25 in wall portion 3, and conversely, inner thermoplastic at point 23 in wall portion 3. The thickness of the layer is greater than the thickness at point 27 in the end cap 10. This premold design includes certain advantages associated with reducing the time of the molding cycle when coating is applied to the initial premold in the overmolding process and a coated premold is produced. Is especially useful when is present. The coating layer 22 may be uniform or may be composed of a plurality of fine layers, as described above and as shown in FIG. 4A, as discussed below.

FIG. 4A shows a portion of the wall cross section of the preform 21 in which the coating layer 22 comprises a plurality of layers 112. The layer 110 is an inner layer of the premold, and the plurality of layers 112 form the outer layer 22 of the premold 21. The outer layer 112 includes a plurality of fine layers of material, such as those manufactured using, for example, the lamella injection molding (LIM) technique disclosed by Hutchinson, wherein at least one of the fine layers. One is high T_gContaining phenoxy-type material, at least one of the fine layers preferably contains PHAE and has a high T_gHigh T if the phenoxy-type material and PHAE are separate layers_gThe phenoxy-type material is on the outside of the PHAE layer. As will be appreciated by those skilled in the art, not all premolds 21 of the type shown in FIG. 4 need to have an outer layer containing a plurality of fine layers as shown in FIG. 4A.

FIG. 5 is a cross-sectional view showing a further embodiment of a representative coated preform 31 without limitation. The coated premold 31 differs from the premolds 20 and 21 shown in FIGS. 3 and 4 mainly in that the coating layer 22 is attached on the neck portion 2 and the body portion 4, respectively. ..

The premolds and container layers of the present invention can have relative thicknesses that vary from one premold or container to another, resulting in a given layer and final reserve. The thickness of the part or container can be selected at a given point or throughout the container to suit the particular end application for the coating process or container. Further, as described above, the coating layer in the premolded and container embodiments disclosed herein may include a single material or some fine layers of two or more materials. ..

Typically, the coated preform (eg, as shown in FIGS. 3-5) is subjected to an extension-blown molding process to form a bottle or other container. As shown in FIG. 6, the coated premold 20 is placed in a blow molding mold 28 having a cavity 30 corresponding to the desired container shape. The coated premold 20 is heated in the blow molding mold 28 by vertically elongating the premold to push air into the premold and horizontally elongate the premold 20. And expand, resulting in the pre-molded part 20 in the shape of a blow molding mold, forming a coated container. The outer layer of the premold has a high T_gDue to the inclusion of the phenoxy type material, the amount of sticking of the injection molded container is significantly reduced, if not completely eliminated, as compared to the PHAE coated container. The blow molding operation is typically limited to the body portion 4 of the premold, and the neck portion 2 with threads, opening ring, and support ring retains the original shape formed within the premold. ..

FIG. 7 shows an embodiment of a typical coated container 40 according to the present invention. Here, the container 40 is of a type molded from a coated premold 20, for example, as shown in FIG. The container 40 includes a neck portion 2 and a main body portion 4 corresponding to the neck portion 2 and the main body portion 4 of the coated preformed part 20 of FIG. As illustrated, the neck portion 2 is further characterized by the presence of threads 8 which provide a means for fixing the cap onto the container.

When looking at the coated container 40 in cross section, the structure can be seen, as shown in FIG. The coating 42 covers the entire outer surface of the body portion 4 of the container 40 and rests just below the support ring 6. The inner surface 50 of the container should be made of FDA approved material (preferably PET) for consumables, leaving only the inner surface uncoated for contact with beverages or foods. In one embodiment, the coating thickness 44 on the container is preferably about 0.020 to about 0.060 inches (about 0.51 to about 1.52 mm), more preferably about 0.030 to about 0.040 inches for use with carbonated beverages. It is (about 0.76 to about 1.02 mm), and the thickness 46 of the inner layer is preferably about 0.080 to about 0.160 inches (about 2.03 to about 4.064 mm), and more preferably about 0.100 to about 0.140 inches (about 2.540 to about 3.556). The final wall thickness 48 of the coated container 40 is preferably about 0.140 to about 0.180 inches (about 3.556 to about 4.572 mm), more preferably about 0.150 to about 0.170 inches (about 3.810 to). It is about 4.318 mm). Preferably, on average, the final wall thickness of the vessel 40 is largely due to the thickness of the inner layer.

Pre-molds as described above and coated according to the present invention have a high T._gIn a bath containing a dispersion of phenoxy-type and PHAE resin, or in a first bath containing a dispersion of PHAE and high T_gIt may be produced by continuously dipping and coating the premolded article in a second bath containing a phenoxy-type material. Immersing the premold in a resin-containing bath can be done manually, such as by using a holding rack, or by a fully automated process, which may include a blow molding process in the final stage. Good.

Preferably, the bath has a high T_gThe dispersion of the phenoxy-type material and the PHAE material is preferably contained in the water in which the resin material is dispersed. These resins may be used in any form, but when used with most materials, smaller size particles disperse more easily than larger particles. Generally high T_gBoth phenoxy-type and PHAE materials form stable water-based dispersions. As described above, the dispersion may be further stabilized by the addition of a weak acid, such as lactic acid or phosphoric acid.

The immersion coating dispersion of the present invention preferably contains from about 10 to about 60% by weight, more preferably from about 20 to about 50% by weight, and most preferably from about 30 to about 40% by weight. The temperature of the dispersion in the bath is preferably from about 0 ° C to about 100 ° C, more preferably from about 25 ° C to about 50 ° C. High T based on the total weight of the resin_gThe weight ratio of phenoxy-type material to PHAE is preferably in the range of about 10:90 to about 50:50, more preferably about 20:80 to about 40:60, based on the total weight of the two resins. ..

In the dip coating, an article, preferably an injection molded thermoplastic premold, is prepared. When the article is injection molded, the mold is cooled at a rate fast enough to maintain the amorphous form of the thermoplastic resin during the injection molding process rather than the crystallizable form. Processes for producing thermoplastic articles, such as pre-molded articles, by injection molding are generally well known in the art. The surface of the article is preferably free of any oils, surfactants, mold release agents, etc. so that the coating material can adhere directly to the substrate.

Once PHAE and high T_gOnce the desired dispersion of the phenoxy-type material resin is prepared, the article is immersed in the resin dispersion in the bath to form a layer of resin dispersion on the article. If the article is a premolded article, it is preferably immersed down to the underside of the support ring 6. The dispersion may be stationary or flowing. Preferably, the article is rotated to be immersed in the coating composition. For articles of 1 inch diameter, the rotational speed is preferably from about 30 to 80 rpm, more preferably from about 40 rpm to about 70 rpm, and most preferably from about 50 to about 60 rpm. As a result, the article is sufficiently covered. As will be appreciated by those skilled in the art, the rotational speed is preferably even slower for larger objects, as the velocity of the surface through the dispersion is proportional to its diameter, depending on the circumference of the object. For example, when the diameter is doubled, the rotational speed should reduce the coefficient by about 2. The article is preferably immersed for a time that allows it to be completely covered. Generally, only about 0.25 to about 5 seconds are required, but longer and shorter times may be used, depending on the application. Soaking for longer periods of time is not expected to give any further coating benefits. Therefore, the premold is preferably immersed in the resin dispersion in the bath for a time not exceeding about 30 seconds, more preferably about 2-5 seconds.

The article is then drawn out of the bath and dried until substantially no liquid material from the dispersion remains on or in the surface coating. The article may be dried by any method known in the art, such as air drying, vacuum drying, infrared (IR drying) and / or heating. The drying method depends on the liquid material in the dispersion and the desired drying rate. Additional dipping and drying steps may be performed to create additional layers, if desired. The thickness of the coating is preferably about 0.01 to about 3 mm, more preferably about 0.1 to about 1 mm. Preferably, the coated article is dried prior to any further process such as injection molding.

The turbidity of the coating composition should also be considered in determining the soaking time and soaking rate. If the container is immersed too quickly, the coating composition may wavy, splatter, and cause coating imperfections. In addition, dispersions of many coating compositions form bubbles and / or bubbles, which can interfere with the coating process. To reduce or completely eliminate bubbling and / or bubbles, the immersion rate is preferably adjusted to avoid excessive agitation of the coating composition. If necessary, an antifoaming agent may be added to the coating dispersion.

The coated premolds produced from the dip coating are preferably of the type shown in FIG. The coating 22 adheres only to the main body portion 4 of the premolded product, and the neck portion 2 has no coating. In these applications where the contents of the container blown from the premold are food or beverage, the inner 16 of the coated premold has a high T._gPhenoxy forms and PHAE resins have not been approved by the FDA for contact with food and beverages and should not be coated with these resins.

Further, the coated article according to the present invention may be obtained by spray coating. According to the method of the present invention, the premolded article or other article has a high T._gSprayed with aqueous dispersions containing phenoxy-type and PHAE resins, or these articles are first sprayed with dispersions containing PHAE and then high T._gIt may be continuously sprayed with a second dispersion containing a phenoxy-type resin, and each resin may be dispersed to form the above-mentioned type of aqueous dispersion for the immersion coating. Spray coating of articles can be performed manually or by using a device that provides spraying and post-spray processing on a single machine.

A preferred device for spray coating a thermoplastic premold is disclosed in US Pat. No. 4,538,542 (Kennon et al.), Which teaching is cited herein by reference to the extent necessary to describe the device. , This device is commercially available from Nordson Corporation, Amherst, Ohio. The device disclosed by Kennon et al. Includes a spray coating chamber, a drying chamber and a conveyor for moving preforms between the two chambers. The device may further include an excess spray recovery system.

Preferably, in the spray coating process, each article is secured and mounted on a conveyor by a portion of equipment constructed and adapted for this purpose. For example, when a premold is spray coated, the neck of each premold is fixed by the device. The article is preferably uniformly spaced on the conveyor and carried in a spray coating chamber, preferably air-free, passing in close proximity to a series of spray nozzles. The dispersion is sprayed through a nozzle and applied to the outer surface of each article premold as it passes through the chamber, providing a wet coating layer. The article is preferably preheated prior to coating by any useful method known in the art, in order to facilitate the adhesion of the resin to the article and to prioritize the evaporation of the aqueous material in the dispersion. Will be done.

When a dip coating is used, the article is preferably rotated while being sprayed with the coating composition. Again, the 1 inch diameter article preferably rotates at a speed of about 30-80 rpm, more preferably at a speed of about 40-about 70 rpm, most preferably at a speed of about 50 rpm-about 60 rpm, and has a larger diameter. The rotation speed for is proportionally slower. This allows sufficient coverage of each article. The speed of rotation should be adjusted for larger article diameters.

The article is preferably sprayed for a sufficient amount of time to cover the article sufficiently. Generally, about 0.25 to about 5 seconds is sufficient, but longer or shorter times may be required depending on the article and coating composition. When using a dip coating, it is unlikely that it will provide additional benefits over a longer period of time, and therefore the article is preferably sprayed with the resin dispersion in the bath for a time not exceeding about 30 seconds. Will be done. More preferably, the article is sprayed for about 2 to about 5 seconds.

The properties of the coating composition should be taken into account when determining the spray time, nozzle size and shape, etc. If the spray rate is too high and / or the nozzle size is incorrect, the coating composition may splatter and cause coating defects. If the speed is too slow and / or the nozzle size is incorrect, the resulting coating may be thicker than desired. When using immersion, foaming and / or air bubbles may also interfere with the coating process, but may be avoided by choosing a liquid connection to avoid excessive agitation of the spray rate, nozzles, and coating composition. .. If necessary, an antifoaming agent may be added to the coating dispersion.

Wet, sprayed and coated articles are carried out of the spray coating chamber to the drying chamber, where when dipping coatings are used, the drying chamber can be an oven, multiple heating lamps (eg, IR lamps), or wet. It may include any other source of thermal energy that provides the temperature required to evaporate and / or remove the liquid in the coating layer. As will be appreciated by those skilled in the art, the temperature should not be high enough to deform or damage the coated article. As the article passes through the drying chamber, the liquid evaporates, leaving a dried and / or cured coating on the premold.

For the sink coating process of the present invention, the article is PHAE and / or high T, like a shower curtain or waterfall._gIt passes through a sheet of flowing dispersion of phenoxy-type material. As mentioned above with respect to the spray coating and immersion coating methods, the resins may be applied together in a single dispersion or in succession to separate dispersions. Preferably, the sink coating is carried out by the presence of the article in the flow of the coating composition for a very short period of time. The article needs to pass through the sheet for a sufficient amount of time to cover the surface of the article. Again, it does not give any additional benefit to the coating over a longer period of time. To provide a uniform coating, the article is preferably rotated as it passes through a sheet of coating composition. Again, the 1-inch article rotates at a speed of preferably about 30-80 rpm, more preferably about 40-about 70 rpm, most preferably about 50-about 60 rpm, and the speed of rotation for larger diameters is proportional. slow. More preferably, the article rotates and is placed at an angle as it passes through the flow of dispersion. The angle of the article is preferably an acute angle with respect to the flow surface of the dispersion. This advantageously allows for overall coverage of the article without covering the neck or interior of the hollow article.

Dispersions of the coating material are preferably contained in other suitable articles that are in liquid communication with the production line in the tank or closed system and are preferably recycled to prevent waste of the unused coating composition. This may be achieved by returning the flow to the coating composition tank, but is preferably achieved in a manner that prevents bubbling and bubbling, as bubbling and bubbling can interfere with the coating process. The dispersion of the coating composition preferably migrates from the bottom or center of the tank to prevent or reduce foaming and bubble formation. Further, in order to further reduce bubbling and bubbling, it is preferable to slow down the flow of the dispersion before returning it to the coated tank. This can be done by means known to those skilled in the art. If desired, at least one antifoaming agent may be added to the coating dispersion.

In selecting the appropriate flow rate for the dispersion of the coating composition, several variables were considered to provide proper sheeting, including flow rate, article length and diameter, line velocity, and article spacing. Should be. The flow velocity determines the accuracy of the flow of the dispersion. If the flow rate is too fast or too slow, the dispersion may not evenly coat the article. If the flow rate is too high, the material may splatter and / or overrun the production line, resulting in incomplete coating of the article, wasted coating composition, foaming and / or bubble problems. is there. If the flow rate is too slow, the coating composition may only partially coat the article.

In addition, the length and diameter of the article to be coated should be taken into account when choosing the flow velocity. A sheet of material should adequately cover the entire article and therefore may require adjustment of the flow velocity if the length and diameter of the article vary. Appropriate flow velocities are readily determined by those skilled in the art.

Another factor to consider is the spacing of the articles on the line. A "wake effect" may be observed as the article moves through the stream of dispersion. Proper coating may not be received if one article passes through a stream of dispersion immediately after another. Therefore, it is important to monitor the velocity and centerline of the article. The speed of the article depends on the output of the particular device used.

Advantageously, the preferred method is PHAE and / or high T, with virtually no excess material requiring removal._gIt provides a sufficiently effective adhesion of a phenoxy-type resin. However, in certain applications, it may be necessary to remove excess coating composition after the article has been coated by either a dip coating method, a spray coating method, or a flow coating method. Preferably, the speed of rotation and gravity normalize the sheet on the article and remove excess material. If the retention tank for the coating composition is arranged in such a way that the article passes over the tank after coating, the rotation and gravity of the article will cause excess material dripping from the article into the coating composition tank. drop down. This allows excess material to be recycled without any additional effort. If the tank is arranged in such a way that excess material does not drip back into the tank, any other suitable means of capturing excess material and returning it for reuse may be used.

If the above methods cannot be performed due to the manufacturing environment or inadequate conditions, various methods and devices known to those of skill in the art may be used to remove excess material. For example, wipers, brushes, air knives or airflows may be used alone or in combination. Further, any of these methods may be combined with the above-mentioned method utilizing rotation and gravity. Preferably, any excess material removed by these methods is recycled for further use.

After the article is coated and excess material is removed, the coated article is dried and / or cured. Preferably, infrared (IR) heating is used in the drying and curing process. For example, a 1000W General Electric Q1500 T3 / CL Quartzline Tungsten-Halogen quartz IR lamp is the preferred IR source. Equivalent sources may be purchased from any of the many vendors, including General Electric and Phillips. The intensity of the IR source may vary to provide the desired drying rate and / or multiple sources may be used.

In addition, the use of infrared heating allows the coating to dry without overheating the substrate. Furthermore, it was found that the use of IR heating can reduce brushing and improve chemical resistance.

Curing and / or drying can be done without additional air, but IR heating is preferably combined with forced air. The air used may be of any useful temperature. The combination of IR and air curing provides the inherent attributes of the preferred embodiments with excellent chemical resistance, fog resistance and scratch resistance. Moreover, although not bound by any particular theory, the chemical resistance of the coating is believed to be a function of cross-linking and curing. The more adequate the cure, the greater the chemical and scratch resistance.

Several factors (eg, coating material, adhesion thickness, and article substrate) should be considered in determining the time required for the coating to dry and cure sufficiently. Different coating materials cure at different rates. In addition, as the solidity increases, the curing rate decreases. Generally, for articles with about 0.05 to about 0.75 grams of coating material, the cure time is about 10 to 120 seconds, but longer or shorter times are available for article size, coating thickness, and cure / cure. It may be necessary depending on the drying method.

The use of airflow in addition to IR heating regulates the surface temperature of the article and provides flexibility in controlling radial heat penetration. If a particular embodiment requires a slower cure rate or deeper IR penetration, it can be controlled using airflow, IR irradiation exposure time, IR lamp frequency, or a combination thereof.

Preferably, the article rotates when it is dried, for example by being exposed to the output of an IR heater. Again, the 1-inch article rotates at preferably about 30-80 rpm, more preferably about 40 rpm-about 70 rpm, most preferably about 50 rpm-about 60 rpm, with proportionally slower rotation speeds for larger diameters. If the rotation speed is too high, the coating will scatter and the coating of the article will be uneven. If the rotation speed is too slow, the article dries unevenly unless the exposure to IR irradiation is evenly distributed over the coated surface of the article. Gas heaters, UV irradiation, frames, etc. may also be used in addition to or in place of IR heating.

The article is then combined with a curing process to cool in the process to provide improved chemical resistance, fog resistance, and scratch resistance. This is believed to be due to the removal of volatiles after a single coating and during a continuous coating. In one embodiment, the cooling process is carried out at ambient temperature. In another embodiment, the cooling process is facilitated by the use of forced or cooling air at ambient temperature.

In addition, the cooling time is affected by the time point in the process in which cooling occurs. In a preferred embodiment, a plurality of coatings are applied to each article. If the cooling step is before the subsequent coating, the cooling time may be reduced as increasing the temperature of the article may improve the coating process. Although the cooling time varies, it is generally about 5 to about 40 seconds for a 24 gram premold with a coating having about 0.05 to about 0.75 grams of coating material.

Although the present invention is disclosed in specific embodiments and examples, the present invention is described in other alternative embodiments and / or uses and obvious modifications beyond the specific disclosed embodiments, as well as those. It will be understood by those skilled in the art that it extends to the equivalent of. Therefore, the invention is not intended to be limited by the particular disclosure of preferred embodiments herein.

<figref num="1">It is a figure which shows the uncoated preform which can be coated using the coating and method of this invention.</figref><figref num="2">It is sectional drawing of the preformed part shown in FIG.</figref><figref num="3">It is sectional drawing of the coated premolded article of this invention.</figref><figref num="4">FIG. 3 is a cross-sectional view of the coated premolded product of the present invention, which has a layer thickness different from that of the preformed product shown in FIG.</figref><figref num="4A">It is a figure which shows a part of the wall cross section of the preformed part of FIG. 4, and the covering layer has a plurality of layers.</figref><figref num="5">It is sectional drawing of the coated premold article of this invention which covers the entire outer surface.</figref><figref num="6">It is sectional drawing of the premolded part in the cavity of the blow molding apparatus used for manufacturing the coated container of this invention.</figref><figref num="7">It is a figure which shows the coated container of this invention.</figref><figref num="8">FIG. 7 is a cross-sectional view of the covered container shown in FIG.</figref>

Code description

1, 20, 21, 31 Preform, 2 Neck, 3 Wall, 4 Body, 6 Support Ring, 8 Threads, 10 End Cap, 12, 26 Preform Thickness, 14 Outer Surface, 16 Inner Surface, 18 openings, 22 coating layers, 23, 25 points in the wall, 24 layer thickness, 27, 29 points in the end cap, 28 injection mold, 30 cavities, 40 containers, 42 coatings, 44 coatings Thickness, 46 inner layer thickness, 48 wall thickness, 50 inner surface of container, 110, 112 layers