HK1134058B - Coating compositions suitable for use as a wood stain and/or toner - Google Patents

Description

Coating compositions suitable for use as wood stains and/or toners

Cross Reference to Related Applications

This application claims priority to U.S. provisional patent application serial No. 60/797,441, filed on 4.5.2006, the entire contents of which are incorporated herein by reference.

Technical Field

The present invention relates, inter alia, to a coating composition, a substrate at least partially coated with a multi-layer composite coating system comprising a coating layer deposited from the coating composition, and a method of improving the adhesion of the multi-layer composite coating system to a substrate.

Background

There are many considerations in protective and decorative coating systems for substrates such as wood substrates, including cabinets, floors, furniture, and the like. As will be appreciated, such coating systems typically consist of more than one coating layer. Porous substrates such as wood are typically coated with a multi-layer composite coating system including a toner layer (toner layer), a colorant layer (stain layer), a sealant layer, and a top coat layer. Generally, the toner layer and/or the colorant layer are colored layers (coloring layers), i.e., they provide a coloring effect. The sealant layer is typically a protective layer that is sanded to provide a finish, while the topcoat is typically a protective layer that provides surface properties such as scratch and mar resistance.

In many cases, one or more of the various coating layers of such multilayer composite coating systems are deposited from coating compositions that include radiation curable species, such as resins that are curable by exposure to ultraviolet ("UV") radiation. Such resins can provide coatings that exhibit good properties, such as adhesion, and are generally desirable for wood finishing applications because of the heat sensitivity of wood, which often makes certain thermosetting coatings undesirable.

However, there are some disadvantages to using certain radiation curable materials in the coating composition. For example, when wiping of the colorant and/or toner composition is desired, toxicity issues may prevent the inclusion of certain radiation curable materials.

Accordingly, it would be desirable to provide coating compositions, such as colorant and toner compositions, suitable for use as wiping colorants and/or toners that can be used in combination with coatings comprising radiation curable materials to provide multi-layer composite coating systems exhibiting acceptable properties, including acceptable adhesion properties and blister resistance.

Summary of The Invention

In certain aspects, the present invention relates to coating compositions, such as wood stain and/or toner (wood stain and/or toner) compositions, comprising a film-forming resin, a colorant, a long chain alkyl group-containing polymerizable ethylenically unsaturated compound, and a diluent.

In other aspects, the present invention relates to coating compositions, such as wood stain and/or toner compositions, comprising a film-forming resin, a radiation cure initiator, a colorant, a long chain alkyl group-containing polymerizable ethylenically unsaturated compound, and a diluent.

In other aspects, the present invention relates to methods of improving the adhesion of a multilayer composite coating system to a porous substrate. The methods of the invention comprise the steps of: a radiation cure initiator and a long chain alkyl group-containing polymerizable ethylenically unsaturated compound are included in a wiping stain and/or toner composition via which the colored layer (colorant layer) of the multilayer composite coating system is deposited, wherein the multilayer coating system comprises at least one coating layer deposited from a radiation curable composition.

In other aspects, the present invention relates to a multilayer composite coating system comprising a color layer and at least one of a sealant layer and a topcoat layer. The colored layer of these coating systems is deposited from a coating composition comprising a film-forming resin, a radiation cure initiator, a colorant, a long chain alkyl group-containing polymerizable ethylenically unsaturated compound, and a solvent. In addition, the sealant and/or topcoat layers are deposited from a radiation curable composition and applied over at least a portion of the color layer.

The invention also relates to a substrate at least partially coated with the coating composition or the multilayer composite coating system and a method for coating a substrate.

Detailed description of embodiments of the invention

For the purposes of the following detailed description, it is to be understood that the invention may assume various alternative variations and step sequences, except where expressly specified to the contrary. Moreover, other than in any operating examples, or where otherwise indicated, all numbers expressing, for example, quantities of ingredients used in the specification and claims are to be understood as being modified in all instances by the term "about". Accordingly, unless indicated to the contrary, the numerical parameters set forth in the following specification and attached claims are approximations that may vary depending upon the desired properties to be obtained by the present invention. At the very least, and not as an attempt to limit the application of the doctrine of equivalents to the scope of the claims, each numerical parameter should at least be construed in light of the number of reported significant digits and by applying ordinary rounding techniques.

Notwithstanding that the numerical ranges and parameters setting forth the broad scope of the invention are approximations, the numerical values set forth in the specific examples are reported as precisely as possible. Any numerical value, however, inherently contains certain errors necessarily resulting from the standard deviation found in their respective testing measurements.

Further, it will be understood that any numerical range recited herein is intended to include all sub-ranges subsumed therein. For example, a range of "1 to 10" is intended to include all sub-ranges between (and including) the recited minimum value of 1 and the recited maximum value of 10, that is, all sub-ranges having a minimum value equal to or greater than 1 and a maximum value of equal to or less than 10.

In this application, the use of the singular includes the plural and plural encompasses singular, unless specifically stated otherwise. In addition, in this application, the use of "or" means "and/or" unless specifically stated otherwise, although "and/or" may be explicitly used in certain instances.

In certain embodiments, the present invention relates to coating compositions, such as stain or toner compositions, suitable for application to porous substrates, such as wood. The term "porous substrate" as used herein refers to a substrate that contains pores or interstices that allow the liquid composition to penetrate into the surface of the substrate. The term "stain (stain)" as used herein refers to a translucent composition that can stain a porous substrate, such as wood, while allowing a portion of the substrate's natural color and texture to show through. The term "toner" as used herein refers to a composition that performs a similar function as a colorant (stain) in that it can color a porous substrate, however, a "toner" is typically a low solids composition (no more than 5% by weight solids and at least 95% by weight solvent) and is typically applied to a substrate at a low film thickness prior to the application of the colorant (stain).

In certain embodiments, the colorant or toner compositions of the present invention are suitable for use as a wiping colorant or wiping toner. As used herein, the terms "wiping stain" and "wiping toner" refer to, respectively, stain and toner compositions suitable for application to a porous substrate wherein excess material, after being applied to the substrate and allowed to penetrate into the surface, can be safely removed by wiping with a cloth or similar implement. For purposes of the present invention, "wiping stains" and "wiping toners" should be distinguished from "non-wiping" or "penetrating" stains or toners in which the composition, when applied to a porous substrate, penetrates the surface of the substrate to the extent that there is no significant amount of excess material remaining on the surface to be removed.

Furthermore, for the purposes of the present invention, the terms "wiping colorant" and "wiping toner" refer to compositions that are substantially free, or in many cases completely free, of (meth) acrylates (described below) that do not include long chain alkyl groups, which if present in any significant amount would render the composition unsuitable for wiping applications where personnel may be exposed to the uncured composition. Examples of (meth) acrylates that do not include long chain alkyl groups, which in certain embodiments are substantially or completely absent from the compositions of the present invention, include, inter alia, methyl (meth) acrylate, ethyl (meth) acrylate, hydroxyethyl (meth) acrylate, and propyl (meth) acrylate.

The term "(meth) acrylate" as used herein is intended to include both acrylates and methacrylates. As used herein, the terms "substantially free of" and "substantially absent" mean that the material, if present, is present in the composition as an incidental impurity. In other words, the material does not affect the properties of the composition. The term "completely free" as used herein means that the substance is not present in the composition at all.

The coating composition of the present invention comprises a film-forming resin. The term "film-forming resin" as used herein refers to a resin that, when removed from any diluent or carrier present in the composition or cured, can form a self-supporting continuous film on at least a horizontal surface of a substrate.

The film-forming resin used in the composition of the present invention is not limited and may include, for example, any film-forming resin commonly used in the art, such as polyurethanes, acrylics, vinyls, melamines, polyvinyl chlorides, polyolefins, polyureas, polycarbonates, polyethers, polyesters, epoxies, silicones, polyamides, and the like, so long as the composition is suitable for use as a wiping stain or wiping toner in certain embodiments. For example, in certain embodiments, the film-forming resin comprises an alkyd resin. The term "alkyd resin" as used herein means a synthetic resin that is the reaction product of a polyacid or anhydride, a polyol, and an oil fatty acid. Such resins are typically prepared by polycondensation of various polybasic acids, polyols and fatty acids. The term "oil fatty acid" as used herein includes, for example, drying oils, semi-drying oils, and non-drying oils, including mixtures thereof. As will be appreciated by those skilled in the art, the coating compositions of the present invention will be capable of undergoing oxidative cure when one or more drying oils, one or more semi-drying oils, or a mixture of drying and semi-drying oils is used. Similarly, if a mixture of at least one of a drying oil or a semi-drying oil and a non-drying oil is used and the mixture is predominantly drying and/or semi-drying, the composition will also undergo oxidative cure. By "predominantly drying" and/or "semi-drying" is meant that at least about 45% of the oil used is drying and/or semi-drying. Both drying and semi-drying oils contain carbon-carbon double bonds capable of undergoing oxidative crosslinking, while non-drying oils either do not contain such bonds or do not contain a sufficient number of such bonds to effect curing.

Examples of suitable drying and semi-drying oils include castor oil, dehydrated castor oil, cottonseed oil, fish oil, linseed oil, menhaden oil, oiticica oil, palm kernel oil, perilla oil, safflower oil, sardine oil, soybean oil, sunflower oil, tall oil, tung oil and walnut oil. Examples of suitable non-drying oils include valeric acid, heptanoic acid, 2-ethylhexanoic acid, nonanoic acid, isononanoic acid, lauric acid, coconut oil fatty acid, stearic acid, and branched fatty acids containing 18 carbon atoms. Primarily drying/semi-drying oils are generally more suitable for use in the wood stains of the present invention.

Suitable polyols that may be used in forming the alkyd resin include glycerol, neopentyl glycol, cyclohexanedimethanol, ethylene glycol, propylene glycol, pentaerythritol, neopentanediol, diethylene glycol, dipropylene glycol, trimethylene glycol, trimethylolpropane, dipentaerythritol, tripentaerythritol, and the like.

Suitable polyacids/anhydrides that can be used to form the alkyd resin include polycarboxylic acids and anhydrides thereof. Examples of suitable polycarboxylic acids include phthalic acid, isophthalic acid, terephthalic acid, tetrahydrophthalic acid, hexahydrophthalic acid, adipic acid, azelaic acid, glutaric acid, 3-diethylglutaric acid, malonic acid, pimelic acid, sebacic acid, suberic acid, succinic acid, 2-dimethylsuccinic acid, 2-methylsuccinic acid, dodecenylsuccinic acid, itaconic acid, fumaric acid, maleic acid, citraconic acid, diethylmaleic acid, and trimellitic acid; anhydrides of those polybasic acids are also suitable. The polyacid having more than 3 acid moieties or higher polyfunctional alcohol should not be used in an amount that would cause gelation of the alkyd resin during preparation.

In certain embodiments, such as certain instances where the composition comprises a toner composition, the film-forming resin comprises a cellulosic resin. The term "cellulose resin" as used herein refers to a thermoplastic polymer known as a cellulose derivative, and examples thereof include: nitrocellulose; organic and mixed esters of cellulose such as cellulose acetate, cellulose propionate, cellulose butyrate and cellulose acetate butyrate; and organic ethers of cellulose such as ethyl cellulose.

In certain embodiments, such as certain instances where the coating composition includes a colorant (stain), the film-forming resin is present in the coating composition of the present invention in an amount of from 0.25 to 15 percent by weight, or in some embodiments from 9 to 15 percent by weight, or in other embodiments from 10 to 12 percent by weight, based on the total weight of the composition. In other embodiments, such as where the coating composition includes a toner (toner), the film-forming resin is present in the coating composition of the present invention in an amount of from 0.25 to 5 weight percent, or in some embodiments from 0.5 to 2 weight percent, or in other embodiments from 0.5 to 1.5 weight percent, based on the total weight of the composition.

In certain embodiments, the coating compositions of the present invention further comprise a radiation cure initiator. The term "radiation-cured" as used herein refers to polymerization that occurs when a material is exposed to actinic radiation, such as Electron Beam (EB), UV light, or visible light.

Radiation curing mechanisms include cationic and/or free radical curing mechanisms. As will be appreciated by those skilled in the art, in a cationic cure mechanism the reactive functional groups of the compounds react by means of positively charged chemical species, while in a free radical cure mechanism the reactive functional groups of the compounds react by means of free radical (uncharged) intermediate species.

In certain embodiments, the radiation cure initiator comprises a photoinitiator selected from a cationic photoinitiator and/or a free radical photoinitiator. As used herein, the term "cationic photoinitiator" refers to a photoinitiator that initiates radiation curing by a cationic curing mechanism, while the term "free radical photoinitiator" refers to a substance that initiates radiation curing by a free radical curing mechanism. For example, where the coating compositions of the present invention are to be used in a coating system in combination with a coating layer deposited from a radiation curable composition comprising a radiation curable species susceptible to cationic cure, as described in more detail below, it is often desirable to include a cationic photoinitiator in the coating compositions of the present invention. In contrast, where the coating compositions of the present invention, as described in more detail below, are to be used in a coating system in combination with a coating layer deposited from a radiation curable composition comprising a radiation curable species susceptible to free radical cure, it is often desirable to include a free radical photoinitiator in the coating compositions of the present invention.

Examples of cationic photoinitiators suitable for use in the present invention include, for example, onium salts, aromatic diazonium salts of complex halides, certain metallocenes, and combinations thereof.

Suitable onium salts include, for example, those having the formula: r₂I⁺MX_z、R₃S⁺MX_z ^-、R₃Se⁺MX_z ^-、R₄P⁺MX_z ^-And R₄N⁺MX_z ^-Wherein each R is an organic group having 1 to 30 carbon atoms, such as an aromatic carboxylic acid group having 6 to 20 carbon atoms. Each R group may be substituted with 1 to 4 monovalent hydrocarbon groups such as alkoxy groups having 1 to 8 carbon atoms, alkyl groups having 1 to 16 carbon atoms, nitro groups, chlorine, bromine, cyano groups, carboxyl groups, mercapto groups, or aromatic heterocyclic groups exemplified by pyridyl, thienyl and pyranyl groups. MX_z ^-Is a non-basic, non-nucleophilic anion, e.g. an inorganic anion such as BF₄ ^-、B(C₆F₅)₄ ^-、PF₆ ^-、AsF₆ ^-、SbF₆ ^-、SbCl₆ ^-、HSO₄ ^-、ClO₄ ^-、FeCl₄ ^-、SnCl₆ ^-Or BiCl₅ ^-(ii) a Anions of organic sulfonic acids such as benzenesulfonic acid, dodecylbenzenesulfonic acid or 3-nitrobenzenesulfonic acid; or an anion of a perfluoroalkylsulfonic acid such as perfluorobutanesulfonic acid, perfluoroethanesulfonic acid, perfluorooctanesulfonic acid, or a combination thereof.

More specific examples of suitable onium salts are diaryliodonium salts of sulfonic acids; diaryliodonium salts of boronic acids, such as tolylcumylium tetrakis (pentafluorophenyl) borate; bis (dodecylphenyl) iodonium hexafluoroarsenate; bis (dodecylphenyl) iodonium hexafluoroantimonate; dialkylphenyliodonium hexafluoroantimonate; triarylsulfonium salts of sulfonic acids; triarylsulfonium salts of perfluoroalkylsulfonic acids; and triarylsulfonium salts of aryl sulfonic acids; triarylsulfonium salts of perfluoroalkylsulfonic acids, or combinations thereof.

Suitable aromatic diazonium salts of complex halides include, for example, 2, 4-dichlorobenzenediazonium tetrachloroferrite (III), p-nitrophenyldiazonium tetrachloroferrite (III), p-morpholinobenzenediazonium tetrachloroferrite (III), 2, 4-dichlorobenzenediazonium hexachlorostannate (IV), p-nitrophenyldiazonium hexachlorostannate (IV), 2, 4-dichlorobenzenediazonium tetrafluoroborate, or combinations thereof.

Also suitable are certain metallocenes, for example of the formula [ R ]^a(Fe¹¹R^b)_c]_d ^+c[x]_c ^-dWherein c is 1 or 2; d is 1, 2,3, 4 or 5; x is a non-nucleophilic anion such as BF₄-，PF₆ ^-，AsF₆ ^-，SbF₆ ^-，SbF₅(OH)^-，CF₃SO₃ ^-，C₂F₅SO₃ ^-，n-C₃F₇SO₃ ^-，n-C₄F₉SO₃ ^-，n-C₆F₁₃SO₃ ^-，n-C₈F₁₇SO₃ ^-，C₆F₅SO₃ ^-Phosphotungstate or silicotungstic acid; r^aIs a pi-arene, and R^bIs an anion of a pi-arene such as a cyclopentadienyl anion. Examples of suitable pi-aromatics are toluene, xylene, ethylbenzene, cumene, methoxybenzene, methylnaphthalene, pyrene, perylene, stilbene, dibenzofuran and dibenzothiophene. An example of a visible light cationic photoinitiator is available from Ciba under the trademark IRGACURE261 (η)₅-2, 4-cyclopentadien-1-yl) (. eta.₆-Isopropylbenzene) Iron (II) hexafluorophosphate. Other commercially available cationic photoinitiators suitable for use in the present invention include CYRACURE UVI-6992 and CYRACURE UVI-6976 from Dow chemical company.

In order to increase the light efficiency or to make the cationic photoinitiator sensitive to specific wavelengths, sensitizers may also be used depending on the type of initiator. Examples are polycyclic aromatic hydrocarbons or aromatic ketone-based compounds, such as benzoperylene, 1, 8-diphenyl-1, 3, 5, 7-octatetraene, or 1, 6-diphenyl-1, 3, 5-hexatriene.

Examples of free radical photoinitiators suitable for use in the present invention include, for example, alpha-scission-type photoinitiators and hydrogen abstraction-type photoinitiators. Cleavage-type photoinitiators include acetophenones, alpha-aminobenzophenones, benzoin ethers, benzoyl oximes, acylphosphine oxides and bisacylphosphine oxides and mixtures thereof. Hydrogen abstraction photoinitiators include benzophenone, michler's ketone, thioxanthone, anthraquinone, camphorquinone, fluorones, coumarins (ketocoumarins), and mixtures thereof.

Specific non-limiting examples of free radical photoinitiators that can be used in the coating composition of the present invention include benzil, benzoin methyl ether, benzoin isobutyl ether, benzophenol (benzophenonol), acetophenone, benzophenone, 4 ' -dichlorobenzophenone, 4 ' -bis (N, N ' -dimethylamino) benzophenone, diethoxyacetophenone, fluoroketones such as the H-Nu series of initiators available from spectra group ltd, 2-hydroxy-2-methyl-1-phenylpropan-1-one, 1-hydroxycyclohexyl phenyl ketone, 2-isopropyl thioxanthone, alpha-aminoalkyl ketones such as 2-benzyl-2-dimethylamino-1- (4-morpholinophenyl) -1-butanone, acylphosphine oxides such as 2, 6-dimethylbenzoyldiphenylphosphine oxide, 2, 4, 6-trimethylbenzoyldiphenylphosphine oxide, bis (2, 4, 6-trimethylbenzoyl) phenylphosphine oxide, 2, 6-dichlorobenzoyldiphenylphosphine oxide and 2, 6-dimethoxybenzoyldiphenylphosphine oxide, bisacylphosphine oxides such as bis (2, 6-dimethyloxybenzoyl) -2, 4, 4-trimethylpentylphosphine oxide, bis (2, 6-dimethylbenzoyl) -2, 4, 4-trimethylpentylphosphine oxide, bis (2, 4, 6-trimethylbenzoyl) -2, 4, 4-trimethylpentylphosphine oxide and bis (2, 6-dichlorobenzoyl) -2, 4, 4-trimethylpentylphosphine oxide, and mixtures thereof.

In certain embodiments, the radiation cure initiator is present in the coating composition of the present invention in an amount of from 0.01 to 10 weight percent, or in some embodiments from 0.01 to 5 weight percent, or in other embodiments from 0.01 to 2 weight percent, based on the total weight of the composition.

Certain embodiments of the coating compositions of the present invention further comprise a colorant (colorant). 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 can 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 (colorants) include pigments, dyes and tints, such as those used in the paint industry and/or listed in the Dry Color Manufacturers Association (DCMA), as well as special effect components (speceleffect composition). 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 agglomerated or non-agglomerated. The colorants can be incorporated into the coating by use of a grind vehicle, such as an acrylic grind vehicle, the use of which will be familiar to those skilled in the art.

Examples of pigments and/or pigment compositions include, but are not limited to, carbazole dioxazine crude pigments, azo, monoazo, disazo, naphthol AS, salts (lakes), benzimidazolone, condensates, metal complexes, isoindolinones, isoindolines and polycyclic phthalocyanines, quinacridones, perylenes, perinones, diketopyrrolylpyrroles, thioindigo, anthraquinones, indanthrones, anthrapyrimidines, flavanthrones, pyranthrones, anthanthrones, dioxazines, triarylcarboniums, quinophthalone pigments, diketopyrrolylpyrrole red ("DPPBO red"), titanium dioxide, carbon black, and mixtures thereof. The terms "pigment" and "colored filler" are used interchangeably.

Examples of colorants include, but are not limited to, those that are solvent-based and/or water-based such as phthalocyanine blue-green or blue, iron oxide, bismuth vanadate, anthraquinone, perylene, aluminum, and quinacridone.

Examples of COLORANTS include, but are not limited to, pigments dispersed in an aqueous-based or water-miscible vehicle, such as AQUA-CHEM896 commercially available from Degussa, Inc, CHARISMA COLORANTS and maxitanelcorants commercially available from Accurate Dispersions of Eastman Chemical, Inc.

As noted above, the colorant (colorant) may be in the form of a dispersion, including but not limited to 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. Nanoparticle dispersions may include colorants such as pigments or dyes having a particle size of less than 150nm, such as less than 70nm or less than 30 nm. Nanoparticles can be prepared by milling a starting organic or inorganic pigment with milling media having a particle size of less than 0.5 mm. Examples of nanoparticle dispersions and methods for making them are described in US patent No.6,875,800B2, which is incorporated herein by reference. Nanoparticle dispersions can also be prepared by crystallization, precipitation, gas phase condensation and chemical attrition (i.e., partial dissolution). To minimize reagglomeration of nanoparticles in the coating, resin-coated nanoparticle dispersions may be used. As used herein, "dispersion of resin-coated nanoparticles" refers to a continuous phase in which is dispersed discrete "composite microparticles" comprising nanoparticles and a resin coating on the nanoparticles. Examples of dispersions of resin-coated nanoparticles and methods for making them are described in U.S. patent application publication 2005-0287348a1, filed 24.6.2004, U.S. provisional application No.60/482,167, filed 24.6.2003, and U.S. patent application serial No. 11/337,062, filed 20.1.2006, which are also incorporated herein by reference.

Examples of special effect components that may be used in the compositions of the present invention include pigments and/or compositions that produce one or more appearance effects (e.g., reflectance, pearlescence, metallic sheen, phosphorescence, fluorescence, photochromism, sensitization, thermochromism, goniochromism, and/or color change). Additional special effect components may provide other perceptible properties such as opacity or texture. In one non-limiting embodiment, the special effect component can produce a color shift, such as a change in the color of the coating when the coating is viewed at different angles. Examples of color effect components are described in U.S. Pat. No.6,894,086, incorporated herein by reference. Additional color effect components may include transparent coated mica and/or synthetic mica, coated silica, coated alumina, transparent liquid crystal pigments, liquid crystal coatings, and/or any component 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 air.

In certain embodiments, the colorant is present in the coating composition of the present invention in an amount of from 0.1 to 30 weight percent, or in some embodiments from 1 to 6 weight percent, based on the total weight of the composition.

Additionally, certain embodiments of the coating compositions of the present invention comprise a diluent. Suitable diluents include organic solvents, water and/or water/organic solvent mixtures. Suitable organic solvents include, for example, alcohols, ketones, aromatic hydrocarbons, glycol ethers, esters, or mixtures thereof. In certain embodiments, the diluent is present in the coating composition of the present invention in an amount of 5 to 80 weight percent, such as 30 to 50 weight percent, based on the total weight of the composition.

The coating compositions of the present invention also comprise a long chain alkyl group-containing polymerizable ethylenically unsaturated compound. The term "long chain alkyl" as used herein refers to an alkyl group containing five (5) or more, or in some cases eight (8) or more carbon atoms. Such long chain alkyl groups may be linear, cyclic or branched.

In certain embodiments, the long chain alkyl group-containing polymerizable ethylenically unsaturated compound comprises an alkyl (meth) acrylate containing from 5 to 18 carbon atoms in the alkyl moiety, such as, inter alia, pentyl (meth) acrylate, hexyl (meth) acrylate, heptyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, dodecyl (meth) acrylate, stearyl (meth) acrylate, isodecyl (meth) acrylate, and/or isobornyl (meth) acrylate.

In certain embodiments, the long chain alkyl group-containing polymerizable ethylenically unsaturated compound comprises a (meth) acrylate having the structure:

wherein R is¹Is H or CH₃And R²Is thatOrWherein R is³Is H or alkyl, R⁴Is alkyl, and R⁵Is an alkyl group containing at least 4 carbon atoms. Such compounds can be prepared by reacting (meth) acrylic acid with a monoepoxide having a significant hydrocarbon chain length, such as a commercially available epoxidized alpha olefin of the formula:

wherein R is⁶Including branched alkyl groups having at least 6 carbon atoms, and in some cases at least 8 carbon atoms.

In certain embodiments, the end groups in the esterifying groups themselves comprise ester groups, such as in the case of the reaction product of (meth) acrylic acid and CARDURA E, a glycidyl ester of a tertiary carboxylic acid, commercially available from Resolution Performance Products, Houston, Texas. The tertiary carboxylic acid is a synthetic blend of isomers of saturated tertiary alkyl monoacids having 9 to 11 carbon atoms. This reaction gives a compound having the structure:

wherein the radical R¹、R³、R⁴And R⁵As defined above. Thus, in certain embodiments of the invention, the long chain alkyl group-containing polymerizable ethylenically unsaturated compound includes compounds having this structure. In other embodiments, (meth) acrylates having ester-containing end groups can be prepared from the reaction of glycidyl (meth) acrylate with long chain organic acids such as tertiary carboxylic acid, neodecanoic acid, or isostearic acid.

The present inventors have surprisingly found that the addition of even relatively small amounts of the aforementioned long chain alkyl group-containing polymerizable ethylenically unsaturated compounds in combination with the aforementioned photoinitiator can significantly improve the adhesion of coatings formed from the composition to wood substrates and subsequently applied radiation curable compositions, and can also improve the blistering resistance of the compositions. Thus, in certain embodiments, the long chain alkyl group-containing polymerizable ethylenically unsaturated compound is present in the coating composition of the present invention in an amount of from 0.01 to 10 weight percent, or in some embodiments from 0.01 to 5 weight percent, or in other embodiments from 0.01 to 2 weight percent, based on the total weight of the composition.

In certain embodiments, the compositions of the present invention comprise an additive comprising organo-silicon or organo-fluorine containing molecules or polymers, such as organosilanes, which the present inventors have found can help impart nickel scratch resistance to coatings formed from the compositions. Non-limiting examples of suitable organosilanes include vinyl and allyl halo, alkoxy, aminoorgano, acryloxy or methacrylate silanes, their hydrolysis products and polymers of the hydrolysis products and mixtures of any of these materials. Some of these silanes are disclosed in U.S. patent nos.2,688,006; 2,688,007, respectively; 2,723,211, respectively; 2,742,378, respectively; 2,754,237, respectively; 2,776,910 and 2,799,598. In certain embodiments, the coating compositions of the present invention comprise an aminosilane, an epoxysilane, or in some cases a mixture thereof.

Non-limiting examples of aminosilanes suitable for use in the compositions of the present invention include monoamino and diamino silanes including gamma-aminopropyltriethoxysilane, N- (trimethoxysilylpropyl) ethylenediamine acrylamide and other similar monoamino and diamino silanes. Lubricant modified aminosilanes may also be used. In certain embodiments, such monoaminosilanes represented by the general formula:

NH₂R-Si-(OR¹)₃

wherein R is an alkylene group having 2 to 8 carbon atoms, and R¹Is a lower alkyl group having 1 to 5 carbon atoms, for example 1 to 2 carbon atoms, or hydrogen. Additional examples of suitable aminosilanes include aminomethyl triethoxysilane, aminopropyl trimethoxysilane, gamma-aminopropyl trimethoxysilane, aminoethylaminopropyl trimethoxysilane, diaminopropyl diethoxy silane, triaminopropyl ethoxysilane, and the like.

Also suitable for use in the compositions of the present invention are epoxysilanes, such as those represented by the formula:

wherein R is¹The sum y as described above is an integer having a value of 1 to 6. Representative examples of such epoxysilanes include beta-hydroxyethyltriethoxysilane, gamma-hydroxypropyltrichlorosilane, bis (delta-hydroxybutyl) dimethoxysilane, delta-hydroxybutyltrimethoxysilane, 2, 3-epoxypropyltrimethoxysilane, 3, 4-epoxybutyltriethoxysilane, and bis (2, 3-epoxypropyl) dimethoxysilane, glycidoxypropyltrimethoxysilane, 3, 4-epoxycyclohexyltriethoxysilane.

Suitable organo-silicon containing polymers include homopolymers, copolymersA polymer or a block polymer, and can be of virtually any length and complexity, so long as the molecule does not affect the desired properties of the coating composition. The polymer may be, without limitation, acrylic, polyester, polyether, polysiloxane, polyurethane, or a combination thereof. In certain embodiments, the polymer comprises the reaction product of one or more monomers, wherein at least one monomer has a pendant silyl group. The polymer may be a homopolymer of a silyl-containing acrylic monomer, or a copolymer of two or more acrylic monomers, one of which contains a pendant silyl group. A suitable acrylic monomer containing pendant silyl groups is gamma-methacryloxypropyltrimethoxysilane (SILQUEST commercially available from OSI Specialties Inc.)A-174 silane). Such monomers may be reacted with suitable vinyl monomers such as acrylic monomers such as methyl (meth) acrylate, ethyl (meth) acrylate, butyl (meth) acrylate, ethylhexyl (meth) acrylate, stearyl (meth) acrylate, benzyl (meth) acrylate, cyclohexyl (meth) acrylate, dodecyl (meth) acrylate, isobornyl (meth) acrylate, hydroxypropyl (meth) acrylate, hydroxyethyl (meth) acrylate, hydroxybutyl (meth) acrylate, trifluoroethyl (meth) acrylate, pentafluoropropyl (meth) acrylate, perfluorocyclohexyl (meth) acrylate, meth) acrylonitrile, glycidyl (meth) acrylate, dimethylaminoethyl (meth) acrylate, diethylaminoethyl (meth) acrylate, methyl methacrylate, ethyl methacrylate, methyl methacrylate, ethyl, (meth) acrylamide, alpha-ethyl (meth) acrylamide, N-butoxymethyl (meth) acrylamide, N-dimethylacrylamide, N-methylacrylamide, acryloyloxymorpholine, and N-methylol (meth) acrylamide, or a combination thereof.

Any number of other silanes containing at least one organic group substituted with one or more amino or epoxy groups may also be used in certain embodiments of the compositions of the present invention. In certain embodiments, the coating compositions of the present invention comprise up to 2 weight percent organosilane, or in some embodiments from 0.1 to 2 weight percent organosilane, based on the total weight of the composition.

In addition, the coating compositions of the present invention may contain other optional components, including ultraviolet absorbers, pigments, and inhibitors known in the art. Various fillers, plasticizers, flow control agents, surfactants, and other known formulation additives may also be used. Also useful in certain embodiments of the coating compositions of the present invention are aluminum or titanium chelate crosslinkers, such as ALUSEC 510-acetyl-di-2-ethoxyaluminum acetate produced by Manchem ltd. or TYZOR TPT-tetraisopropyl titanate produced by DuPont. In certain embodiments, antiskinning agents such as methyl ethyl ketoxime may be added to, for example, improve package stability. In some cases, fillers and matting agents such as clay, talc, silica, and the like may be added. Suitable silicas are commercially available as SYLOID 169 from w.r. grace and Company and as AEROSIL 972 from DeGussa Corporation. Anti-sag additives such as cellulose acetate butyrate 551-0.2 from Eastman Chemicals may also be included as additional performance enhancing additives. Various additives, when used, typically constitute no more than 30 wt%, such as no more than 10 wt%, of the coating composition, based on the total weight of the composition.

The coating composition of the present invention may be applied to any of a variety of substrates. In certain embodiments, however, the coating compositions of the present invention are applied to porous substrates such as paper, paperboard, particle board, fiberboard, wood, plywood, and wood products. A wide variety of woods that can be colored with the compositions of the present invention include, for example, oak, cherry, pine, and maple. These types of wood are used, for example, in the manufacture of kitchen cabinets, bathroom cabinets, tables, desks, dressers and other furniture, and flooring, such as hardwood and parquet flooring.

The coating composition of the present invention may be applied to a substrate by any means known in the art. For example, the coating composition can be applied by brushing, dipping, flow coating, roll coating, and conventional spraying as well as electrostatic spraying.

Once applied, certain embodiments of the coating compositions of the present invention are allowed to soak into the porous substrate for a predetermined amount of time, and in some embodiments of the present invention where the composition is used as a wiping stain or toner, excess wood stain is wiped off. Multiple layers may be applied. When the coating composition of the present invention includes an alkyd-containing wood stain, as described above, the wood stain may then be cured by means of oxidative curing achieved by exposing the coated substrate to ambient or elevated temperature conditions. For example, ambient or elevated temperature conditions may be those that are generally considered "air-drying" or "forced drying" conditions. This is carried out at a temperature of about 13 ℃ to 250 ℃, for example 20 ℃ to 150 ℃ or 50 ℃ to 90 ℃. Oxidative curing in the absence of accelerated conditions can be carried out over a period of days to weeks.

As will be appreciated, additional layers such as sealants and/or topcoats may be applied over the colorant layer and/or toner layer, particularly in the processing of wood substrates. Accordingly, certain embodiments of the present invention are directed to substrates at least partially coated with a multi-layer composite coating system. The term "multilayer composite coating system" as used herein refers to a coating system comprising at least two coating layers applied sequentially to a substrate, such as a porous substrate.

The coating system of the present invention comprises (i) a color layer (colorant layer) deposited from any of the aforementioned coating compositions of the present invention and (ii) at least one of a sealant and a topcoat applied over at least a portion of the color layer and deposited from a radiation curable composition. The term "radiation curable composition" as used herein refers to a composition comprising a radiation curable material. The term "radiation curable material" as used herein refers to a material having reactive components that can be polymerized by exposure to at least one source of actinic radiation as previously mentioned. In certain embodiments, the coating system of the present invention comprises (i) a toner layer (tonner layer) deposited from any of the foregoing inventive coating compositions, (ii) a colorant layer (statin layer) deposited from any of the foregoing inventive coating compositions, wherein the colorant layer is deposited on at least a portion of the toner layer, (iii) a sealant deposited from a radiation curable composition, wherein the sealant is deposited on at least a portion of the colorant layer and/or toner layer, and (iv) a topcoat layer deposited from a radiation curable composition, wherein the topcoat layer is deposited on at least a portion of the sealant. In certain embodiments, the radiation curable composition via which at least one of the sealant and the topcoat are deposited comprises an aqueous composition. In other embodiments, the radiation curable composition via which at least one of the sealant and topcoat are deposited comprises a composition that is substantially free of monofunctional reactive diluents and/or inert solvents, such as the sprayable compositions described in U.S. published patent application nos. 2006/0030634a1, [0020] - [0047], the cited portions of which are incorporated herein by reference.

As used herein, the term "sealant" refers to a protective coating applied directly to a color layer, such as toner and/or dye, and "topcoat" refers to a protective coating applied directly to a sealant. In the coating system of the present invention, the sealant and/or topcoat are deposited from a radiation curable composition, such as a composition comprising a radiation curable species that is susceptible to cationic and/or free radical cure. For example, in certain embodiments, the sealant and/or topcoat are deposited from a composition comprising a polymer comprising an alkyd resin moiety and a free-radically curable moiety (as described, for example, in U.S. patent application publication Nos. 2004-0013895A1, [0005] - [0022 ]), which is incorporated herein by reference.

In certain embodiments, the sealant and/or topcoat are deposited from a radiation curable composition comprising a radiation curable species that readily undergoes cationic curing. In this case, it is generally desirable to include a cationic photoinitiator in the coating composition via which the at least one colored layer is deposited. In other embodiments of the present invention, the sealant and/or topcoat are deposited from a radiation curable composition comprising a radiation curable species that readily undergoes free radical cure. In this case, it is generally desirable to include a free radical photoinitiator in the coating composition via which the at least one coloured layer is deposited.

In certain embodiments of the present invention, a toner and/or colorant is applied to the substrate. The colorant and/or toner may or may not undergo oxidative cure prior to application of the sealant and/or topcoat (application of the sealant/topcoat with uncured colorant and/or toner is understood by those skilled in the art as a "wet-on-wet" application). After application of the sealant and/or topcoat layers, the layers are at least partially cured. While not being bound by any theory, it is believed that some of the radiation curable monomers present in the sealant/topcoat radiation curable composition may migrate into the colorant layer, toner layer, and/or porous substrate during application and prior to curing. The presence of the radiation curable initiator in the colorant layer, toner layer, and/or porous substrate may allow the radiation curable monomers that have migrated therein to be cured during curing of the sealant and/or topcoat. Therefore, interlayer adhesion can be produced, and interlayer adhesion and adhesion to the substrate are improved. However, as noted, the present invention is not limited to this mechanism. Thus, the multilayer composite coatings of the present invention can provide, among other things, a desired level of adhesion, toughness, blistering resistance, appearance, feel, and/or stain/solvent resistance. The term "partial cure" as used herein refers to any curing stage between full cure and no cure.

In certain embodiments, the substrate of the present invention is coated with a multi-layer composite coating that exhibits a tack adhesion (tape adhesion) of at least 50%, the tack adhesion test being performed according to ASTM D-359. In certain embodiments, the coatings exhibit a viscose fastness of at least 85%, or in some cases 100%.

In certain embodiments, the substrates of the present invention are coated with a multi-layer composite coating that exhibits a nickel scratch resistance of at least 8. Nickel scratch resistance is one way to evaluate the scratch resistance of a coating system. The nickel scratch resistance used herein was tested in 5 replicates on a single sample and the results are reported relative to a control coating system. The test may be conducted using a U.S. government 5 minute coin with no apparent wear surface. The nickel was grasped between the thumb and forefinger and the nickel edge was scraped against the surface being coated using moderate to firm pressure. The pressure # required to scrape the coated surface is specified as an integer of 1 to 10, with 1 being the minimum effort and 10 being the maximum effort.

As will be appreciated, the present invention further relates to a method of improving the adhesion of a multi-layer composite coating system to a porous substrate, which adhesion can be measured by the previously described viscose fastness test. The methods of the invention comprise the steps of: a radiation cure initiator and a long chain alkyl group-containing polymerizable ethylenically unsaturated compound are included in a wiping stain and/or toner composition via which the colored layer of the multilayer composite coating system is deposited, wherein the multilayer coating system comprises at least one coating layer deposited from a radiation curable composition.

The present invention also provides a method of at least partially coating a porous substrate with a multi-layer composite coating system. These methods include: (a) applying a color layer to a porous substrate; and (b) applying at least one of a sealer and a topcoat deposited from a radiation curable composition over at least a portion of the colored layer. In the methods of the invention, the pigmented layer is deposited from the coating composition of the invention. The sealant and/or topcoat coating compositions may then be cured. Thus, for example, the sealant and/or topcoat compositions can be cured by irradiation with actinic radiation as known to those skilled in the art. In certain embodiments, curing may be completed in less than 1 minute.

In certain embodiments, the sealant and/or topcoat compositions may be cured using an ultraviolet light source having a wavelength range of 180 to 4000 nanometers. For example, can be madeSunlight, mercury lamp, arc lamp, xenon lamp, gallium lamp, etc. In one example, the total exposure can be 100-2000 mJ/cm by means of a laser having an intensity of 48-360W/cm²E.g., 500 to 1000mJ/cm²The sealant and/or topcoat compositions were cured by a medium pressure mercury lamp (as measured by a POWERMAP UV radiometer commercially available from EIT inc.

Although specific embodiments of the invention have been described above for purposes of illustration, it will be evident to those skilled in the art that numerous variations of the details of the present invention may be made without departing from the inventive concept as defined in the appended claims.

The following examples illustrate the invention and are not to be construed as limiting the invention to their details. All parts and percentages in the examples, as well as throughout the specification, are by weight unless otherwise indicated.

Example 1

Samples A-D were prepared using the components and amounts (in g) shown in Table 1. Samples were prepared by adding the materials to a blending vessel and stirring with an air motor equipped with a Cowles blade for 20-30 minutes.

TABLE 1

Material(s)	Toner A	Toner B	Colorant C	Colorant D
					Acetic acid isobutyl ester	91.399	91.399	-	-
Propylene glycol monomethyl ether acetate	18.287	18.287	-	-
					Mineral oil essence	-	-	429.580	429.580
Bentone SD-11	-	-	8.149	8.149
					Beckosol 1247-T-702	-	-	36.294	36.294
Cymel U-803	-	-	3.718	3.718
					Kaolin clay4	-	-	28.178	28.178
Methyl ethyl ketoxime	-	-	1.213	1.213
					Paraloid B-665	9.668	9.668	-	-
2, 4, 6-trimethylbenzoyl-diphenylphosphine oxide	2.625	2.625	-	-
					Ethanol	182.739	182.739	4.067	4.067
Ethyl acetate	125.049	125.049	-	-
					Acetone (II)	246.049	246.049	-	-
Tint-AYD AL 519 Burnt Umber6	-	-	124.490	124.490
					AL673 Deep Organic Red Tint-AYD7	-	-	12.449	12.449
AL317H Tinting Black Tint-AYD8	-	-	2.385	2.385
					Tint-AYD AL 620 Red Oxide Light9	-	-	4.084	4.084
Neozapon Black NBX5110	-	-	5.727	5.727
					VM&P Naptha HT11	-	-	37.261	37.261
Isopropanol (I-propanol)	-	-	45.000	45.000
					Neozapon Red NB 335 A12	4.582	4.582	-	-
Neozapon Orange NB 251 A13	1.542	1.542	-	-
					Irgasperse Yellow 2R-U14	2.863	2.863	-	-
Irgasperse Brown 4R-U15	1.947	1.947	-	-
					6N1216 burn umber nitrocellulose paste	27.369	27.369	-	-
6R305D quin maroon nitrocellulose paste	4.301	4.301	-	-
					Polymerizable ethylenically unsaturated compounds containing long chain alkyl groups	-	7.184	-	7.426

¹Organoclay available from Elementis Specialties, inc

²Short oil soy alkyd resins supplied by Reichhold Chemicals, Inc

³Butylated urea-formaldehyde resin supplied by Cytec Industries, Inc

⁴Anhydrous aluminium silicates supplied by BASF Catalysts, llc

⁵By Rohm&Haas co. supplied acrylic acid polymer

⁶Long oil alkyd based coloring pastes provided by Elementis Specialties, inc

⁷Long oil alkyd based coloring pastes provided by Elementis Specialties, inc

⁸By Elementis specialtyLong oil alkyd resin based tinting pastes provided by ies, Inc

⁹Long oil alkyd based coloring pastes provided by Elementis Specialties, inc

¹⁰Chromium III based black dyes supplied by BASF corporation

¹¹Supplied by Shell Chemical Co

¹²Chromium III based Red 122 dye supplied by BASF corporation

¹³Chromium III based orange 54 dye supplied by BASF corporation

¹⁴C.i. acid yellow 220 dye supplied by Ciba Pigments

¹⁵C.i. acid brown 282 dye supplied by Ciba Pigments

¹⁶Nitrocellulose based coloring paste provided by Penn Color

¹⁷Nitrocellulose based coloring paste provided by Penn Color

¹⁸The reaction product of (meth) acrylic acid and CARDURA E as described in U.S. Pat. No.6,458,885, column 3, lines 19-51

Examples 2 to 5

Four solid cherry wood pieces were sanded with 180 grit sandpaper and then coated with the combination of toners and colorants described in table 2. The toner was applied at about 10 microns and the colorant was applied at about 100 microns. Immediately after the application of the stain, the wood chips were thoroughly wiped with a wipe to remove excess stain from the wood surface. After wiping the stain, the wood chips were cured at 140 ° f for 15 minutes. After this curing time, it is then sealed with 10-15 microns of a commercially available PPG sealant sold under the trademark R1782Z 49. The sealed sheets were immediately cured with 800mJ of UV light. After UV curing of the sealant, the sheet was sanded with ultra fine sandpaper and coated with 75-80 microns of A1385Z83 commercially available from PPG Industries, Inc. The sheet was then dehydrated at 140 ° f for 8 minutes and cured with 800mJ of UV light. All coatings were applied using a Kremlin HTI spray gun.

TABLE 2

The sheets were tested for adhesion according to ASTM D3359 60 minutes after UV curing. The results of this test are shown in table 3.

TABLE 3

It will be appreciated by those skilled in the art that changes could be made to the embodiments described above without departing from the broad inventive concept thereof. It is understood, therefore, that this invention is not limited to the particular embodiments disclosed, but it is intended to cover modifications within the spirit and scope of the present invention as defined by the appended claims.

Claims (14)

1. A wood stain or wood toner composition comprising:

(a) a film-forming resin, a water-soluble resin,

(b) a colorant,

(c) a long-chain alkyl group-containing (meth) acrylate containing an alkyl group having 8 or more carbon atoms,

(d) a diluent, and

(e) a radiation-curing initiator, which is capable of curing,

wherein the long chain alkyl group-containing (meth) acrylate is present in the composition in an amount of 0.01 to 5 wt% based on the total weight of the composition.

2. The composition of claim 1, wherein the composition is a wiping stain or wiping toner.

3. The composition of claim 1, wherein the film-forming resin is an alkyd resin and/or a cellulosic resin.

4. The composition of claim 1, wherein the radiation cure initiator is a photoinitiator selected from cationic photoinitiators and/or free radical photoinitiators.

5. The composition of claim 4, wherein the photoinitiator is 2, 4, 6-trimethylbenzoyldiphenylphosphine oxide.

6. The composition of claim 1, further comprising an additive that is an organo-silicon and/or organo-fluorine containing molecule and/or polymer.

7. The composition of claim 6, wherein the organo-silicon containing molecules and/or polymers are organosilanes.

8. The composition of claim 7, wherein the organosilane is an aminosilane, an epoxysilane, or a mixture thereof.

9. The composition of claim 1, wherein the long chain alkyl group-containing (meth) acrylate is an alkyl (meth) acrylate containing 8 to 18 carbon atoms in the alkyl moiety.

10. The composition of claim 1, wherein the long chain alkyl group-containing (meth) acrylate is a (meth) acrylate having the structure:

wherein R is¹Is H or CH₃And R²Is that

Wherein R is³Is H or alkyl, R⁴Is alkyl, and R⁵Is an alkyl group containing at least 4 carbon atoms.

11. The composition of claim 10, wherein the long chain alkyl group-containing (meth) acrylate is a (meth) acrylate having the structure:

12. the composition of claim 1, wherein the long chain alkyl group-containing (meth) acrylate is present in the composition in an amount of 0.01 to 1 wt%, based on the total weight of the composition.

13. A method of improving the adhesion of a multi-layer composite coating system to a porous substrate comprising including in a wiping stain and/or toner composition via which is deposited a color layer of the multi-layer composite coating system a radiation cure initiator and a long chain alkyl group-containing (meth) acrylate, wherein the multi-layer coating system comprises at least one coating layer deposited from a radiation curable composition, the long chain alkyl group-containing (meth) acrylate comprising an alkyl group containing 8 or more carbon atoms, the long chain alkyl group-containing (meth) acrylate being present in the composition in an amount of from 0.01 to 5 wt%, based on the total weight of the composition.

14. A multilayer composite coating system comprising a color layer and at least one of a sealer layer and a topcoat layer, wherein the color layer is deposited from a coating composition comprising a film-forming resin, a radiation cure initiator, a colorant, a long chain alkyl group-containing (meth) acrylate, and a diluent, and wherein at least one of the sealer layer and the topcoat layer is deposited from a radiation curable composition and applied over at least a portion of the color layer, the long chain alkyl group-containing (meth) acrylate comprising an alkyl group containing 8 or more carbon atoms, the long chain alkyl group-containing (meth) acrylate being present in the composition in an amount of from 0.01 to 5 wt%, based on the total weight of the composition.