HK1152720A - Substrates and articles of manufacture coated with a waterborne 2k coating composition - Google Patents

Description

Substrates and articles coated with aqueous 2K coating compositions

Cross-referencing

This is U.S. patent application 10/245,028 filed on 9, 17, 2002; us patent application 11/020,921 filed on 23.12.2004; U.S. patent application 11/172,718 filed on 1/7/2005 and a continuation-in-part application of U.S. patent application 11/461,844 filed on 2/8/2006.

Technical Field

The present invention relates to substrates and articles coated at least in part with a base-neutralized aqueous coating composition having a carbodiimide crosslinking agent.

Background

Many substrates, such as fabrics, thermoplastic polyurethanes, ethylene vinyl acetate foams, and leather, have considerable flexibility. It is often desirable to coat these substrates with coatings to improve appearance, water resistance, chemical resistance, scratch resistance, ultraviolet light resistance, and/or durability. It may also be desirable to coat or "decorate" these substrates to provide improved appearance, apply patterns, and the like. Many coatings that improve these properties are hard coatings suitable for use on hard substrates. When hard coatings, such as acrylic coatings, are applied to flexible substrates, the coatings often crack and flake off of the substrate when the substrate is bent. Thus, flexible coatings suitable for use on flexible substrates are desired.

In addition, one or more flexible substrates are often combined as distinct components in an article. It is often desirable to maintain color uniformity between these various components. However, when the parts are made of different kinds of materials, it may be difficult to provide a uniform visual appearance of the article when assembling the parts.

For example, footwear such as athletic shoes often contain different types of materials including natural leather, synthetic leather, vinyl, textiles, foam, and/or rubber. Different coating compositions are conventionally applied to each type of substrate. For example, one type of coating may be applied to a natural leather upper portion of a shoe, and another type of coating may be applied to a synthetic leather upper portion of the shoe. In addition, pigments are often incorporated into the foam midsole of the footwear in order to impart color to the midsole and/or to provide uniformity and/or color coordination between the upper member of the footwear and the midsole. Such use of multiple specialized paints and pigments can result in relatively complex and expensive manufacturing processes, inventory issues, and may also create a need for "color matching" of different paints.

Color matching is the process of "matching" the visual characteristics of more than one coating such that two or more coatings produce the same or substantially the same appearance. Color matching may be desirable when, for example, two different substrates on the same article are coated with two different coatings. Color matching may also be desirable when attempting to determine a coating that matches a previously coated article or part. For example, automotive body shops often paint repaired portions of the body with a coating composition that is often selected to match the color of the original body paint; these color-matched coatings tend to have a different composition than the original coating and may contain a significantly different kind of coating, for example an air-cured coating vs.

While color matched components may have substantially the same appearance under some viewing and lighting conditions, they may not retain the same appearance when the viewing angle is changed, when the spectral distribution of the light source is changed, and/or when the coating has aged. For example, some color-matched components may have the same appearance under daylight conditions, but may not match under fluorescent and/or incandescent lighting. When color matching depends on lighting or viewing conditions, such matching is referred to as conditional or "metameric".

It would be desirable to provide a coating composition that is capable of coating a variety of different kinds of substrates of articles while eliminating the need to perform color matching.

Summary of The Invention

The present invention relates to a compressible substrate at least partially coated with a water borne coating composition comprising: a) at least one base-neutralized active hydrogen-containing film-forming resin; and b) a water-dispersible carbodiimide crosslinker capable of reacting with the film-forming resin to form a crosslinked film.

The present invention further relates to an article comprising: a) a first substrate comprising a first flexible material; and b) a second substrate comprising a second flexible material different from the first flexible material, wherein at least a portion of the first substrate and at least a portion of the second substrate are coated with a waterborne coating composition comprising: i) at least one base-neutralized active hydrogen-containing film-forming resin; and ii) a water-dispersible carbodiimide crosslinker capable of reacting with the film-forming resin to form a crosslinked film.

Detailed Description

The present invention relates to compressible substrates that are at least partially coated with a water-borne coating composition. The aqueous coating composition used in the present invention comprises at least one base-neutralized active hydrogen-containing film-forming resin. "base-neutralized" and like terms indicate that a base is used to neutralize at least a portion of the active hydrogen-containing film-forming resin. Suitable bases include amines and inorganic bases such as lithium hydroxide and potassium hydroxide. Suitable amines include ammonia and any of primary, secondary and tertiary amines. Tertiary amines are particularly suitable.

The base may be present in the aqueous coating composition in an amount necessary to neutralize 60-170% of the active hydrogen-containing film-forming resin. 100% neutralization means a 1: 1 molar ratio of base to acid, and 70% neutralization means a 7: 10 molar ratio of base to acid.

"active hydrogen-containing" and similar terms indicate that the film-forming resin has groups capable of reacting with carbodiimide groups, such as carboxyl, alcoholic hydroxyl, phenolic hydroxyl, and/or thiol groups. Suitable active hydrogen-containing film-forming resins include polyesters, polyurethanes, (meth) acrylic polymers, polyamides, polycarbonates and/or polyethers. The polymers used as film-forming resins in the present invention can be prepared with unreacted carboxylic acid groups to impart acid functionality.

Suitable (meth) acrylic polymers include copolymers containing carboxylic acid groups and sulfur and phosphorus acid groups. These (meth) acrylic polymers and methods for making them are well known in the art. For example, these (meth) acrylic polymers may be synthesized from acid monomers and one or more alkyl (meth) acrylates. Suitable acid monomers include: (meth) acrylic acid, maleic acid, fumaric acid, crotonic acid, itaconic acid, 2-sulfoethyl methacrylate, 2-acrylamido-2-methyl-1-propanesulfonic acid, (meth) acrylamidomethylphosphonic acid, and 2-phosphoethyl (meth) acrylate. The presence of these acid groups facilitates the dispersion of the acrylic polymer in water in the presence of a base neutralizing compound. Monoalkyl esters of maleic acid, fumaric acid and itaconic acid may also be used in the synthesis of the acrylic polymer. As will be appreciated by those skilled in the art and as is conventional for them, (meth) acrylic acid includes both acrylic acid and the equivalent methacrylic acid; the same is true for other compounds having the prefix "(methyl)".

Suitable alkyl (meth) acrylates include aliphatic or cycloaliphatic alkyl esters having from 1 to 30 carbon atoms in the alkyl group, for example from 4 to 18 carbon atoms in the alkyl group. Methyl (meth) acrylate, ethyl (meth) acrylate, butyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, and hydroxyethyl (meth) acrylate are all examples of suitable alkyl (meth) acrylates.

Suitable (meth) acrylic polymers additionally include copolymers synthesized from one of the above monomers with one or more of the following polymerizable ethylenically unsaturated monomers: vinyl aromatic compounds such as styrene and vinyl toluene; nitriles such as (meth) acrylonitrile; amides such as (meth) acrylamide; vinyl and vinylidene halides such as vinyl chloride; and vinylidene chloride and vinyl esters such as vinyl acetate.

Polyesters and alkyds that can be used as film-forming resins in the present invention and methods of making them are well known in the art. For example, polyesters can be prepared via condensation of polyols and polycarboxylic acids. Suitable polyols include ethylene glycol, propylene glycol, butylene glycol, 1, 6-hexanediol, neopentyl glycol, diethylene glycol, glycerol, trimethylolpropane and pentaerythritol. Suitable polycarboxylic acids include succinic acid, adipic acid, azelaic acid, sebacic acid, maleic acid, fumaric acid, phthalic acid, tetrahydrophthalic acid, hexahydrophthalic acid and trimellitic acid.

Polyesters and alkyds may also be formed from acids of sulfur and/or phosphorus, as is well known in the art. Suitable sulfur and phosphorus acids include 2-phosphonobutane-1, 2, 4-tricarboxylic acid and 5-sulfoisophthalic acid.

Polyurethanes that can be used in the film-forming resins of the present invention and methods for making them are well known in the art. For example, the polyurethane can be prepared as follows: the polyester polyols, polycarbonate polyols, polyether polyols or acrylic polyols are reacted with polyisocyanates and acid-functional polyols so that the OH/NCO ratio is greater than 1: 1, neutralized with an amine and then dispersed into water. Alternatively, the polyurethane may be prepared as follows: reacting the polyol, isocyanate and acid functional polyol with an isocyanate such that the OH/NCO equivalent ratio is less than 1: 1, dispersing the prepolymer in water containing an isocyanate chain extender and a neutralizing amine. Polyurethanes prepared in this manner are generally preferred due to their inherent flexibility. Suitable polyisocyanates include aliphatic polyisocyanates, aromatic polyisocyanates, and mixtures thereof.

The active hydrogen-containing film-forming resins useful in the present invention can have a weight average molecular weight greater than 1,000 and a number average molecular weight greater than 500, both as determined by gel permeation chromatography using polystyrene standards. The active hydrogen-containing film-forming resin used in the present invention can have an acid value of from 5mg KOH/g to 738mg KOH/g, such as from 10mg KOH/g to 200mg KOH/g, or from 10mg KOH/g to 45mg KOH/g, or any other combination of values within any of these ranges.

The active hydrogen-containing film-forming resin may be present in the aqueous coating composition at 10 to 100 weight percent, such as 45 to 85 weight percent, where the weight percent is determined by the ratio of resin solids in the active hydrogen-containing film-forming resin to total resin solids of the composition.

The aqueous coating composition used in the present invention further comprises a water-dispersible carbodiimide crosslinker. "Water dispersible" and like terms, when used in conjunction with a carbodiimide, refer to a carbodiimide dissolved or dispersed in an aqueous phase. In order to use certain carbodiimides in the present invention, it may be necessary to modify the carbodiimides to make them water dispersible. Techniques for modifying carbodiimides to render them water dispersible are well known in the art.

Suitable water dispersible carbodiimide crosslinking agents include aliphatic and/or aromatic dinitrogen analogues of carbonic acid having the general structure: RN ═ C ═ NR₁Wherein R and_R1 is independently hydrogen, an aliphatic or aromatic group. The aliphatic group includes an alkyl chain and may include a carbodiimide such as dicyclohexylcarbodiimide. Oligomeric or polymeric carbodiimide crosslinkers can also be used.

The preparation of water dispersible carbodiimide crosslinkers is well known in the art. Suitable water dispersible carbodiimide crosslinkers can be prepared by incorporating small amounts of amines such as dimethylaminopropylamine, and alkyl sulfonates or sulfates into the carbodiimide structure. Suitable water-dispersible carbodiimides can also be prepared by incorporating polyethylene oxide or polypropylene oxide into the carbodiimide structure.

Suitable water-dispersible carbodiimides are commercially available. For example, UCARLINK XL-29SE, XL-20 available from Union Carbide and CARBODILITE VO2-L2 available from Nisshinbo Industries, Inc. may be used in the present invention.

The amount of dispersed carbodiimide in the aqueous medium can be at least 1 wt% based on the weight of the aqueous dispersion, for example from 2 to 60 wt% based on the weight of the aqueous dispersion.

In the aqueous coating composition used in the present invention, the water-dispersible carbodiimide crosslinker may be present at 5 to 50, such as 10 to 35 or 15 to 25, wt% resin solids based on total resin solids.

Optionally, the aqueous coating composition used in the present invention comprises a water dispersible polyisocyanate. "Water-dispersible" and like terms, when used in conjunction with a polyisocyanate, refer to a polyisocyanate dissolved or dispersed in an aqueous phase. In order to use certain polyisocyanates in the present invention, it may be necessary to modify the polyisocyanates to render them water dispersible. Techniques for modifying polyisocyanates to render them water dispersible are well known in the art.

Suitable water-dispersible polyisocyanates include polyfunctional isocyanates and diisocyanates. Suitable polyfunctional isocyanates include a wide variety of monomeric and oligomeric polyfunctional isocyanates. Examples include biuret adducts of 3 molecules of diisocyanate, adducts of at least trifunctional polyols with 1 molecule of diisocyanate per hydroxyl equivalent, isocyanurate group-containing compounds, 1, 3, 5-triisocyanatobenzene, 2, 4, 6-triisocyanatotoluene, and uretdione.

The aqueous coating of the present invention may further comprise one or more additives typically added in the art. The additives may include colorants, plasticizers, antioxidants, hindered amine light stabilizers, UV light absorbers and stabilizers, surfactants, flow control agents, thixotropic agents, fillers, organic cosolvents, reactive diluents, catalysts, grind vehicles, and other conventional adjuvants.

The term "colorant" as used herein refers to any substance that imparts color and/or other opacity and/or other visual effect to the composition. The colorant may be added to the coating in any suitable form, such as discrete particles, dispersions, solutions, and/or flakes. A single colorant or a mixture of two or more colorants can be used in the coating of the present invention.

Examples of colorants include pigments, dyes, and tints, such as those used in the coatings industry and/or listed in the Dry Color Manufacturers Association (DCMA), as well as special effect compositions. The colorant may comprise, for example, a finely divided solid powder that is insoluble but wettable under the conditions of use. The colorant may be organic or inorganic and may be aggregated or non-aggregated. The colorant can be incorporated into the coating by grinding or simple mixing. The colorants can be incorporated into the coating by utilizing a grind vehicle, such as an acrylic grind vehicle, the use of which is well known to those skilled in the art.

Examples of pigments and/or pigment compositions include, but are not limited to, carbazole bisOxazine crude pigments, azo, monoazo, disazo, naphthol AS, salt forms (lakes), benzimidazolones, condensates, metal complexes, isoindolinones, isoindolines and polycyclic phthalocyanines, quinacridones, perylenes, perinones, diketopyrrolopyrroles, thioindigoids, anthraquinones, indanthrones, anthrapyrimidines, flavanthrones, pyranthrones, anthanthrones, dianthranthraquinones, lawsonitrons, lakemidinones, lakemidines, lakemidOxazine, triaryl carbonsQuinophthalone pigments, diketopyrrolopyrrole red ("DPPBO red"), titanium dioxide, carbon black, carbon fibers, graphite, other conductive pigments and/or fillers, and mixtures thereof. The term "pigment"And "colored filler" are used interchangeably.

Examples of dyes include, but are not limited to, those that are solvent-based and/or aqueous, such as acid dyes, azo dyes, basic dyes, direct dyes, disperse dyes, reactive dyes, solvent dyes, sulfur dyes, mordant dyes, such as bismuth vanadate, anthraquinone, perylene aluminum, quinacridone, thiazole, thiazine, azo, indigoid, nitro, nitroso, oxazine, phthalocyanine, quinoline, stilbene, and triphenylmethane.

Examples of tints include, but are not limited to, pigments dispersed in an aqueous-based or water-miscible vehicle such as AQUA-CHEM 896 commercially available from Degussa, inc. and CHARISMA COLORANTS and maxi minor COLORANTS commercially available from Accurate Dispersions of Eastman Chemical, inc.

As noted above, the colorant can be in the form of a dispersion, including but not limited to in the form of a nanoparticle dispersion. Nanoparticle dispersions can include one or more highly dispersed nanoparticle colorants and/or colorant particles that produce a desired visible color and/or opacity and/or visual effect. The nanoparticle dispersion may include a colorant such as a pigment or dye having a particle size of less than 150nm, such as less than 70nm or less than 30 nm. Nanoparticles can be produced by milling raw organic or inorganic pigments with grinding media having a particle size of less than 0.5 mm. Examples of nanoparticle dispersions and their methods of manufacture are described in U.S. Pat. No.6,875,800B 2, incorporated herein by reference. Nanoparticle dispersions can also be produced by crystallization, precipitation, gas phase condensation, and chemical attrition (i.e., partial dissolution). To minimize re-aggregation of the nanoparticles in the coating, a dispersion of resin-coated nanoparticles may be used. As used herein, a "dispersion of resin-coated nanoparticles" refers to a continuous phase in which are dispersed discrete "composite particles" comprising nanoparticles and a resin coating on the nanoparticles. Examples of dispersions of resin-coated nanoparticles and methods for their manufacture are described in U.S. patent application publication 2005-0287348 a1, filed 24.6.2004, and U.S. provisional application No. 60/482,167, filed 24.6.2003, and U.S. patent application No. 11/337,062, filed 20.1.2006, which are incorporated herein by reference. Colorants also include transparent pigments such as those available from Clariant.

Examples of special effect compositions that may be used include pigments and/or compositions that produce one or more appearance effects such as reflectance, pearlescence, metallic sheen, phosphorescence, fluorescence, photochromism, photosensitivity, thermochromism, goniochromism (goniochromism), and/or color change. Additional special effect compositions may provide other perceptible properties such as opacity or texture. In a non-limiting embodiment, the special effect composition can produce a color shift such that the color of the coating changes when the coating is viewed at different angles. Examples of color effect compositions are described in U.S. Pat. No.6,894,086, which is incorporated herein by reference. Additional color effect compositions can include transparent coated mica and/or synthetic mica, coated silica, coated alumina, transparent liquid crystal pigments, liquid crystal coatings, and/or any composition in which interference is caused by refractive index differences within the material and not due to refractive index differences between the surface of the material and the air.

In certain non-limiting embodiments, photosensitive compositions and/or photochromic compositions that reversibly change their color when exposed to one or more light sources can be used in the coatings of the present invention. Photochromic and/or photosensitive compositions can be activated by exposure to radiation of a particular wavelength. When the composition is excited, the molecular structure is altered and the altered structure exhibits a new color that is different from the original color of the composition. When the exposure to radiation is removed, the photochromic and/or photosensitive composition can return to a static state, wherein the original color of the composition is restored. In one non-limiting embodiment, the photochromic and/or photosensitive composition can be colorless in a non-excited state and exhibit color in an excited state. Complete discoloration can occur in milliseconds to several minutes, for example 20 seconds to 60 seconds. Examples of photochromic and/or photosensitive compositions include photochromic dyes.

In one non-limiting embodiment, the photosensitive composition and/or photochromic composition can be associated with and/or at least partially associated with, for example by covalent bonding, with the polymer and/or polymeric material of the polymerizable component. In contrast to some coatings in which the photosensitive composition may migrate out of the coating and crystallize into the substrate, photosensitive compositions and/or photochromic compositions associated with and/or at least partially bound to polymers and/or polymerizable components according to non-limiting embodiments of the present invention have minimal migration out of the coating. Examples of photosensitive and/or photochromic compositions and methods for their preparation are described in U.S. application No.10/892,919, filed on 7, 16, 2004, which is incorporated herein by reference.

In general, the colorant can be present in any amount sufficient to impart the desired visual and/or color effect. The colorant may comprise 1 to 65 weight percent, such as 3 to 40 weight percent or 5 to 35 weight percent of the composition of the present invention, wherein weight percent is based on the total weight of the composition.

Other suitable coating components include one or more texture-enhancers that improve the surface feel and/or increase the stain resistance of the coating. In one non-limiting embodiment, the texture enhancer imparts a soft feel to the coating. The term "soft touch" as used herein refers to a coated substrate that exhibits altered tactile properties when touched, such as a velvety or leather-like feel. The texture enhancer may be an additive that can be added to the coating composition, such as a silica leveler and/or a wax additive. Examples of silica levelers may include ACEMATT OK 412 and ACEMATT TS 100, available from Degussa, Inc. Examples of wax additives may include polytetraethylene oxide (polytetraethylene oxide), fluorinated waxes, polyethylene waxes, and natural waxes, such as paraffin wax and/or carnauba wax. In another non-limiting embodiment, the texture enhancer may be incorporated into the polyurethane resin itself. For example, components that will impart larger "soft segments" to the polyurethane may be used. Examples include polytetramethylene ether glycol available from Invista, inc. under the trade name TERATHANE 2000.

As noted above, the present invention relates to compressible substrates at least partially coated with one or more of the aqueous coating compositions described herein. "compressible substrate" and similar terms refer to a substrate that is capable of undergoing a compressive deformation and returning to substantially the same shape once the compressive deformation is stopped. The term "compressive deformation" and similar terms refer to a mechanical stress that at least temporarily reduces the volume of a substrate in at least one direction. A compressible substrate is, for example, a substrate having a compressive strain of 50% or greater, such as 70%, 75% or 80% or greater. Specific examples of compressible substrates include those comprising foam and polymer capsules filled with air, liquid and/or plasma. The "foam" may be a polymer or natural material comprising an open cell foam and/or a closed cell foam. "open cell foam" refers to a foam comprising a plurality of interconnected air cells; "closed cell foam" refers to a foam comprising discrete closed cells. Examples of foams include, but are not limited to, polystyrene foams, polyvinyl acetate and/or copolymers, polyvinyl chloride and/or copolymers, poly (meth) acrylimide foams, polyvinyl chloride foams, polyurethane foams, thermoplastic polyurethane foams, and polyolefin-based foams and polyolefin blends. Polyolefin-based foams include, but are not limited to, polypropylene foams, polyethylene foams, and ethylene vinyl acetate ("EVA") foams. The EVA foam may comprise a flat sheet or plate or a molded EVA foam, such as a midsole. Different types of EVA foam may have different types of surface porosity. Molded EVA may comprise a dense surface or "skin" while flat sheets or slabs may exhibit a porous surface.

The present invention further relates to an article comprising: a) a first substrate comprising a first flexible material; and b) a second substrate comprising a second flexible material different from the first flexible material, wherein at least a portion of the first substrate and at least a portion of the second substrate are coated with a waterborne coating composition comprising: i) at least one base-neutralized active hydrogen-containing film-forming resin; and ii) a water-dispersible carbodiimide crosslinker capable of reacting with the film-forming resin to form a crosslinked film. The aqueous coating composition may be any of the compositions described above.

The term "flexible substrate" refers to a substrate that is capable of undergoing mechanical stress, such as bending, stretching, and the like, without significant irreversible change. In certain embodiments, the flexible substrate is a compressible substrate as described above. Other flexible substrates include non-rigid substrates such as woven and non-woven fiberglass, woven and non-woven glass, woven and non-woven polyester, Thermoplastic Polyurethane (TPU), synthetic leather, natural leather, finished synthetic leather, rubber, polyurethane elastomers, synthetic fabrics, and natural fabrics. The "fabric" may include natural and/or synthetic fabrics such as cloth (fabric), vinyl and polyurethane coated cloth (fabric), mesh, netting, cord (cord), yarn, and the like, and may be composed of, for example, canvas, cotton, polyester, KEVLAR, polymer fibers, polyamides such as nylon and the like, polyesters such as polyethylene terephthalate and polybutylene terephthalate and the like, polyolefins such as polyethylene and polypropylene and the like, rayon, polyvinyl polymers such as polyacrylonitrile and the like, other fibrous materials, cellulosic materials, and the like.

In one non-limiting embodiment of the invention, the article comprises footwear. The term "footwear" as used herein includes sports and athletic shoes, dress men's and women's shoes, casual men's and women's shoes, children's shoes, sandals, flip-flops, boots, work boots, outdoor footwear, orthopedic shoes, slippers, and the like. Examples of footwear components include soles, midsoles, upper materials, and liners. As specific, non-limiting examples, athletic footwear may include natural leather, synthetic leather, and/or textile uppers, as well as EVA foam interlayers.

The term "coating" as used herein refers to a material that forms a substantially continuous layer or film on a substrate. The coating may be applied to flexible substrates, including but not limited to fabrics, at any desired thickness, such as a thickness suitable to achieve a desired mechanical and/or visual effect. In one non-limiting embodiment, the coating may penetrate into a portion of the surface of the flexible substrate while the coating is held on the outer surface of the flexible substrate. In certain embodiments the outer surface of the flexible substrate is coated in whole or in part. "exterior surface" refers to a surface that is at least partially exposed when the flexible substrate is assembled into a finished product. Examples relating to the use of fabrics include the outer surface of a garment or the outer surface of a floor covering. Examples relating to footwear include that portion of the midsole or other footwear components that are visible in the finished shoe (i.e., when all of the footwear components are assembled). Thus the outer surface is not a surface covered and thereby concealed by another component, except that at least a portion of the surface remains un-concealed and/or visible on the exterior or outside of the finished product.

The coating compositions used in the present invention are suitable for the preparation of any type of coating, and are particularly suitable as topcoats on substrates. In one embodiment, the coating of the present invention may be used as a single application coating or a single layer coating. In another embodiment, the coating may be used as one or more layers in a multi-layer coating, where each coating may contain the same or different additives. The coatings of the present invention may be used alone or in combination with other coatings. In certain embodiments, it may be desirable to use an adhesion promoting layer on the substrate to be coated. In certain embodiments, it may be desirable to apply one or more of the above-described coatings to a substrate in a certain design or pattern. The design and/or pattern may use one color, or two or more colors of the above-described coatings. In certain embodiments it may be desirable to apply one or more coatings to substantially all of the substrate. In this manner, one or more colors may be imparted to the substrate.

The coating compositions used according to the present invention can be applied to flexible substrates, including fabrics, by any known means, such as brushing, spraying, rolling, slot coating and/or dipping. The coating may also be applied by any known dyeing, printing or coloring means, such as screen printing, ink jet printing, jet dyeing, jet injection dyeing, transfer printing, and the like. The above-described means may be computer controlled, as will be appreciated by those skilled in the art, and may include the application of color to the substrate on a pixel-by-pixel basis, such as discussed in U.S. Pat. Nos. 6,792,329 and 6,854,146, both of which are incorporated by reference in their entirety. A "pixel" is the smallest area or location in a pattern or on a substrate that can be individually assigned or addressed in a given color. For example, the above-described manner may be used to print patterns and/or colors onto a substrate; a "pattern" on a substrate may mean that the substrate has been colored, e.g., pixel by pixel, by applying a colorant to the substrate (typically in a predetermined manner). In various methods for dyeing, printing, or otherwise imparting color to a substrate, computers and digital design software can be used to generate digital designs that are input into digitally controlled dyeing, printing, or coloring equipment; the above equipment is commercially available and can be used according to the manufacturer's instructions.

Curing of these coatings may include flash evaporation at ambient or elevated temperatures followed by thermal baking in order to obtain optimum performance. The coatings of the present invention are typically deposited on flexible substrates to a thickness of 0.1 to 3 mils. In one embodiment, the coating is deposited to a thickness of 0.5 to 1.0 mils.

As used herein, unless otherwise expressly specified, all numbers such as those expressing values, ranges, amounts or percentages may be read as if prefaced by the word "about", even if the term does not expressly appear. Additionally, any numerical range recited herein is intended to include all sub-ranges subsumed therein. Singular forms include plural forms and vice versa. For example, although reference is made herein to "a" compressible substrate, "a" base neutralized active hydrogen-containing film-forming resin, and "a" carbodiimide, mixtures of one or more of each of these and any other components can be used. The term "polymer" as used herein refers to oligomers as well as homopolymers and copolymers, and the prefix "poly" refers to two or more. The terms including and similar refer to including but not limited to.

Examples

The invention will be further illustrated by the following non-limiting examples. Table 1 contains the formulation data for the waterborne coating compositions of the present invention. Table 2 describes the crosslinker system used in the exemplary coating system. Table 3 lists the pot lives of the various crosslinked waterborne coating systems.

Exemplary coating compositions of the present invention are prepared by taking 100g of a commercially available primer composition and then adding an amount of base. An amine is employed as the base in the exemplary composition. The primer is then mixed with an amine to form the coating composition of the present invention. Specific compositional information for the examples is shown below in table 1.

TABLE 1 aqueous coating compositions of the invention

Examples	T408Black BC1	Dimethylethanolamine2	% neutralized5	Approximate pH6
					1	100g	Is free of	77.1	7.24
2	100g	0.10g	93.2	8.28
					3	100g	0.20g	109.2	8.58
4	100g	0.25g	117.2	8.76
					5	100g	0.30g	125.2	8.92
6	100g	0.35g	133.3	9.04
					7	100g	0.40g	141.3	9.10
8	100g	0.50g	157.3	9.24

	T413Blue BC3
					9	100g	Is free of	95.2	7.71
10	100g	0.20g	122.0	8.70
					11	100g	0.50g	162.0	9.17

	T400White BC4
					12	100g	Is free of	90.9	8.25
13	100g	0.20g	113.6	8.74
					14	100g	0.50g	147.6	9.25

¹T408 Black primer, available from PPG Industries, Inc.

²Dimethylethanolamine is a hydroxylamine available from Huntsman petrochemicals

³T413 Blue primer, available from PPG Industries, Inc.

⁴T400 White primer available from PPG Industries, Inc.

⁵Acid equivalent in the primer divided by amine equivalent times 100

⁶Using T408The black primer formed two different sets of samples. The pH values were used for only one set of data. The maximum deviation between the pH values in the different groups of samples was ± 0.27.

TABLE 2 crosslinker systems for exemplary coating systems

The following components were mixed together to form a crosslinker system for use in the exemplary coating system.

¹Polyisocyanate products available from Bayer Corporation

²Solvents available from Eastman Chemical Company

³Carbodiimide products available from Union Carbide Corporation

TABLE 3 exemplary waterborne coating systems

¹The pot life was measured by the following method. Initially, the primer and crosslinker systems were combined in a container (time ═ 0). The container is then tipped over at various time intervals (e.g., 10 minutes, 25 minutes, 40 minutes, etc.) to verify liquid flow. The time at which the container was tipped over and the liquid no longer flowed was recorded as the pot life.

Conclusion

The present invention provides aqueous coating compositions having good pot life. As shown in Table 3 above, the pot life of the crosslinked aqueous coating composition of the present invention can be increased by increasing the% neutralization of the aqueous coating composition.

Example A

An aqueous polycarbodiimide resin "a" was prepared as follows:

TABLE 4

Composition (I)		Parts by weight
				Feed #1
Desmodur W1		16.68
			Phospholene oxides (Phospholene oxides)		0.25
	Feed #2
			Dibutyl tin dilaurate		0.0015
	Feed #3
			N-methyl pyrrolidone		10.13
Ethylene glycol		0.62
				Feed #4
Jeffamine M1000(XTJ-506)2		18.22
				Charge #5
Deionized water		51.84
			Abex 20053		2.25

¹Desmodur W is methylene-bis- (4-cyclohexyl diisocyanate) from Bayer Materials Science, LLC

²Jeffamine M1000 is a polyetheramine from Huntsman (EO/PO molar ratio 6.3, MW 1000)

³Abex 2005 is a proprietary anionic surfactant from Rhodia

Charge #1 was added to a 2 liter four-necked flask equipped with a motor driven stainless steel stirring blade, water cooled condenser, nitrogen inlet, and heating mantle with thermometer connected through a temperature feedback control device. The flask contents were heated to 140 ℃ and held at this temperature until the isocyanate equivalent weight was > 350eq/g as measured by titration. The temperature was then reduced to 95 ℃ and feed #2 was added. Charge #3 was added over 10 minutes and the reaction mixture was held at 90-100 ℃ until the NCO equivalent stopped at about 1300 eq/g. Feed #4 was added and the mixture was held at 90-100 ℃ until the IR spectrum indicated the absence of NCO characteristic band. The batch was cooled to 60-65 ℃ and charge #5, which had been preheated to 60-65 ℃, was added to the reaction flask over 20 minutes while maintaining the temperature below 65 ℃.

Samples of the polycarbodiimide dispersion were left in a 120 ° F warm room for 4 weeks with the resin remaining dispersed.

Example 15

A thermosetting waterborne composition was prepared comprising a carboxylic acid group-containing polyurethane and the polycarbodiimide of example a. The composition was prepared from the following ingredients.

¹A polyurethane dispersion was prepared as follows: isophorone diisocyanate was reacted with polyether diol (POLYMEG 2000) and dimethylolpropionic acid (2.85: 0.95: 1.27 equivalent ratio) in Methyl Ethyl Ketone (MEK) solvent to produce an NCO-prepolymer having an NCO equivalent of 2663 and an acid number of 21.1. The NCO prepolymer was chain extended with adipic acid dihydrazide in water and partially neutralized with dimethylethanolamine and MEK stripped in vacuo to yield a dispersion of 34.66 wt% resin solids.

²Orange pigment from Dayglo Color Corp

³Silicon flow additive from Goldschmidt Chemical

⁴Rheology agent from BYK Chemie

⁵Degassing agent from BYK Chemie

The thermosetting composition was sprayed on a substrate as mentioned below, and cured at 170 ℃ for 20 minutes to give a cured coating having a film thickness of about 1 mil. The coated substrates were tested for flexibility and compression resistance. The test results are reported below:

examples	Compression1	Flexibility2
			15	Qualified	Greater than 40,000

¹The compression test is a test designed by NIKE corporation (KIM compression) which simulates the up and down running motion of a shock strut (look column) of a compression sports shoe to measure repeated compression. A flexible polyurethane substrate coated as described above, approximately 2.5 square centimeters and 2.5 centimeters thick was placed in a holder and the plate directly above the holder impacted the sample to the point where the material was compressed 50% of its original height. The compressed size will therefore be about 2.5 x 1.75 cm. The impact/compression was repeated 5-10 times per second and continued until the coating failed or the count reached 100,000 cycles. One cycle is one compression/one relaxation and two cycles is two compression/two relaxation.

²The flexibility test is also a test designed by NIKE using a Bally deflectometer. In a test, a flexible polyurethane substrate coated as described above, approximately 2.5 square centimeters and 2.5 centimeters thick, was placed in a jig and folded 90 degrees (coating side out) to simulate the bending experienced by the upper of an athletic shoe when used for running. The samples were folded 20,000 times and inspected for cracks in the coating. If no cracks are shown, the specimen is folded an additional 20,000 times and the coating is again inspected for cracks. The test was continued until the coating cracked.

Claims (21)

1. A compressible substrate at least partially coated with a water borne coating composition comprising:

a. at least one base-neutralized active hydrogen-containing film-forming resin comprising a polyurethane dispersion prepared by:

(i) reacting a polyol, an isocyanate, and an acid functional polyol with an isocyanate at a 0H/NCO equivalent ratio of less than 1: 1, thereby forming an isocyanate functional prepolymer; and

(ii) dispersing the isocyanate functional prepolymer in water comprising an isocyanate chain extender and a neutralizing amine, thereby forming the polyurethane dispersion;

b. a water-dispersible carbodiimide crosslinker capable of reacting with the film-forming resin to form a crosslinked film, wherein the water-dispersible carbodiimide is a water-dispersible oligomeric carbodiimide and/or a water-dispersible polymeric carbodiimide, wherein the water-dispersible carbodiimide crosslinker is prepared by incorporating a small amount of an amine;

c. a flow control agent; and

d. a water-dispersible polyisocyanate.

2. The substrate of claim 1, wherein the base-neutralized, active hydrogen-containing film-forming resin has a total neutralization value of from 100 to 200.

3. The substrate of claim 1, wherein the active hydrogen-containing film-forming resin has a number average molecular weight greater than 500 as determined by gel permeation chromatography using polystyrene standards.

4. The substrate of claim 1, wherein the substrate comprises a foam.

5. The substrate of claim 4, wherein the foam comprises an ethylene vinyl acetate foam.

6. The substrate of claim 4, wherein said foam comprises a thermoplastic polyurethane foam.

7. The substrate of claim 1, wherein the substrate comprises a fabric.

8. The substrate of claim 1, wherein the substrate comprises an air-filled polymeric bladder.

9. Footwear comprising the substrate of claim 4.

10. An article of manufacture, comprising:

a) a first substrate comprising a first flexible material; and

b) a second substrate comprising a second flexible material different from the first flexible material,

wherein at least a portion of the first substrate and at least a portion of the second substrate are coated with an aqueous coating composition comprising:

i) at least one base-neutralized active hydrogen-containing film-forming resin comprising a polyurethane dispersion prepared by:

reacting a polyol, an isocyanate, and an acid functional polyol with an isocyanate at an OH/NCO equivalent ratio of less than 1: 1, thereby forming an isocyanate functional prepolymer; and

dispersing the isocyanate functional prepolymer in water comprising an isocyanate chain extender and a neutralizing amine, thereby forming the polyurethane dispersion;

i i) a water-dispersible carbodiimide crosslinker capable of reacting with the film-forming resin to form a crosslinked film, wherein the water-dispersible carbodiimide is a water-dispersible oligomeric carbodiimide and/or a water-dispersible polymeric carbodiimide, wherein the water-dispersible carbodiimide crosslinker is prepared by the incorporation of a small amount of an amine, and

iii) a flow control agent; and

iv) a water-dispersible polyisocyanate.

11. The article of claim 10, wherein the first and second substrates independently comprise natural leather, synthetic leather, vinyl, nylon, thermoplastic polyurethane, cloth, foam, and/or rubber.

12. The article of claim 10, wherein the first substrate comprises foam and the second substrate comprises synthetic and/or natural leather.

13. The article of claim 10, wherein the coating further comprises a colorant.

14. The article of claim 10, wherein the article is footwear.

15. The article of claim 14, wherein the footwear is an athletic shoe.

16. The article of claim 10, wherein the first and/or second substrate comprises air-filled polymeric capsules.

17. Footwear comprising the substrate of claim 8.

18. The compressible substrate of claim 1 wherein said water dispersible polyisocyanate is selected from the group consisting of biuret adducts of 3 molecules of diisocyanate, adducts of at least trifunctional polyols with 1 molecule of diisocyanate per hydroxyl equivalent, isocyanurate group containing compounds, 1, 3, 5-triisocyanatobenzene, 2, 4, 6-triisocyanatotoluene, and uretdione.

19. The article of claim 10 wherein said water-dispersible polyisocyanate is selected from the group consisting of biuret adducts of 3 molecules of diisocyanate, adducts of at least trifunctional polyols with 1 molecule of diisocyanate per hydroxyl equivalent, isocyanurate group-containing compounds, 1, 3, 5-triisocyanatobenzene, 2, 4, 6-triisocyanatotoluene, and uretdione.

20. The compressible substrate of claim 1 wherein the amine added during the preparation of the water dispersible carbodiimide crosslinker is dimethylaminopropylamine.

21. The article of claim 10, wherein the amine added during the preparation of the water-dispersible carbodiimide crosslinker is dimethylaminopropylamine.