Disclosure of Invention
In certain aspects, the present invention relates to waterborne coating compositions, such as 1-K, environmentally curable coating compositions. These coating compositions comprise (a) acrylic copolymer resin particles comprising pendant carbonyl functional groups and (b) a crosslinker comprising at least two functional groups reactive with the carbonyl functional groups of the acrylic copolymer. In these compositions, the acrylic copolymer resin particles have a calculated glass transition temperature ("Tg") of at least 40 ℃ and comprise the reaction product of reactants comprising: (i) at least 50 weight percent hydrophobic acrylic monomer based on the total weight of the reactants, and (ii) an acrylic monomer comprising aldehyde and/or ketone functionality. In addition, the hydrophobic acrylic monomer comprises (A) at least 60 wt.% of a styrenic monomer, based on the weight of the hydrophobic acrylic monomer, and (B) a (meth) acrylic acid ester of an alkyl alcohol, wherein the alkyl portion of the alcohol is linear or branched and comprises at least 4 carbon atoms.
In other aspects, the invention also relates to methods of using the above-described coating compositions and substrates at least partially coated with a coating deposited from the above-described coating compositions.
Detailed Description
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.
Moreover, it should 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 therebetween and to include the recited minimum value of 1 and the recited maximum value of 10, that is, to have 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. Further, in this application, "or" means "and/or" unless specifically stated otherwise, even though "and/or" may be explicitly used in certain instances.
As previously mentioned, certain embodiments of the present invention are directed to coating compositions, such as 1-K, waterborne, environmentally curable coating compositions. As used herein, the term "1-K" refers to a storage stable coating composition wherein all components of the composition are stored together in a single container and the viscosity of the composition should not increase significantly until such time that the composition is no longer suitable for convenient use in depositing a coating. Indeed, in certain embodiments, the coating compositions of the present invention exhibit a shelf life of up to at least 1 year when stored in a sealed container at 140 ° F, as measured by no significant viscosity increase.
As used herein, "aqueous" refers to a solvent or carrier fluid used in a coating composition for the coating composition, i.e., the continuous phase, is substantially or primarily water. For example, in certain embodiments, at least 80% by weight of the carrier fluid is water, based on the total weight of the carrier fluid. In addition, certain of the coating compositions of the present invention are "low VOC coating compositions". As used herein, the term "low VOC composition" means a composition that does not contain more than three (3) pounds of VOC per gallon of the coating composition. As used herein, the term "VOC" refers to a compound that has at least one carbon atom and which is removed from the composition during drying and/or curing. Examples of "VOCs" include, but are not limited to, alcohols, benzene, toluene, chloroform, and cyclohexane.
As used herein, the term "ambient curable" refers to a coating composition that, after application to a substrate, is capable of curing in ambient air at an air relative humidity of 10-100%, such as 25-80%, and a temperature in the range of-10 to 120 ℃, such as 5 to 80 ℃, sometimes 10-60 ℃ and in other cases 15-40 ℃. As used herein, the term "cure" refers to a coating wherein any crosslinkable components of the composition are at least partially crosslinked. In certain embodiments, the cross-link density, i.e., the degree of cross-linking, of the cross-linkable component ranges from 5% to 100%, such as from 35% to 85%, or sometimes, from 50% to 85% of full cross-linking. One skilled in the art will appreciate that the presence and extent of crosslinking, i.e., crosslink density, can be determined by various methods, such as Dynamic Mechanical Thermal Analysis (DMTA) conducted under nitrogen using a Polymer Laboratories MK III DMTA analyzer.
As previously mentioned, the coating compositions of the present invention comprise acrylic copolymer resin particles comprising pendant carbonyl functionality. As used herein, the term "copolymer" refers to a polymer that is the reaction product of two or more different reactants, such as two or more different monomers. As used herein, "polymer" includes oligomers as well as prepolymers, the prefix "poly" being referred to herein as "two or more". As used herein, the term "acrylic copolymer" refers to a copolymer of two or more acrylic reactants, such as two or more different acrylic monomers, i.e., two or more different polymerizable ethylenically unsaturated reactants. As used herein, "carbonyl" refers to a functional group that includes a carbon atom double-bonded to an oxygen atom (C = O).
In the coating composition of the present invention, the acrylic copolymer resin is present in the form of particles which are in the dispersed phase of the emulsion in which water is the essential, and sometimes the only, component of the continuous phase. In certain embodiments, the resin particles are uniformly small in size, i.e., less than 20% of the resin particles after polymerization have a particle size greater than 5 microns, sometimes greater than 1 micron. In certain embodiments, the resin particles have an average diameter of no more than 500 nanometers, such as no more than 400 nanometers, no more than 300 nanometers, or, in some cases, no more than 200 nanometers. Further, in certain embodiments the resin particles have an average particle size of at least 1 nanometer, such as at least 5 nanometers, at least 10 nanometers, at least 50 nanometers, or sometimes, at least 100 nanometers. The particle size can be measured by photon correlation spectroscopy as specified in international standard ISO 13321. The mean particle size values reported herein were measured by photon correlation spectroscopy using a malvern zetasizer 3000HSa according to the following method. Approximately 10mL of ultrafiltered deionized water and 1 drop of the homogeneous sample were added to a clean 20mL vial and mixed. The cuvette was rinsed and approximately half filled with ultrafiltered deionized water to which about 3-6 drops of the diluted sample were added. Once the bubbles were removed, the cuvette was placed in a Zetasizer 3000HSa using a corrector Control window in Zetasizer Software (100-. Particle size measurements were then done with a Zetasizer 3000 HSa.
In certain embodiments, the acrylic copolymer resin particles are the primary, or sometimes essentially the primary source of resin solids in the coating compositions of the present invention. Thus, in certain embodiments, the above-described resin particles are present in the coating composition of the present invention in an amount of at least 50 percent by weight, such as at least 70 percent by weight, at least 80 percent by weight, at least 90 percent by weight, or sometimes, at least 92 percent by weight, based on the total weight of resin solids in the coating composition.
In certain embodiments, the coating compositions of the present invention are substantially free, or sometimes completely free, of any other resin particles, such as polymer particles having an average diameter between 1 and 50 nanometers. In this specification, "substantially free" means that the amount of the other resin particles present in the total concentration of the composition is less than 1 weight percent, such as no more than 0.5 weight percent or no more than 0.1 weight percent, based on the total weight of resin solids in the coating composition. By "completely free" is meant that no other polymer particles are present in the composition at all.
The acrylic copolymer resin particles included in the coating composition of the present invention are the reaction product of reactants comprising: (i) at least 50 weight percent, based on the total weight of the reactants, of a hydrophobic acrylic monomer, and (ii) an acrylic monomer comprising an aldehyde and/or ketone functional group.
Acrylic monomers comprising aldehyde and/or ketone functional groups, as used herein, refers to acrylic monomers comprising at least one group represented by the following structure:
wherein R is a monovalent hydrocarbon group and R' is hydrogen or a monovalent hydrocarbon group. Specific examples of suitable such monomers include, but are not limited to, those disclosed in U.S. patent No. 4,786,676, column 3, lines 39-56, U.S. patent No. 4,959,428, column 2, lines 29-56, and U.S. patent No. 5,447,970, column 2, line 59 to column 3, line 15, the citations of which are incorporated herein by reference. The abovementioned monomers may be used individually or in mixtures. In fact, it has been surprisingly found that the use of monomers comprising aldehyde and/or ketone functional groups is crucial for obtaining 1-K aqueous coating compositions exhibiting good adhesion to various plastic and metal substrates.
In certain embodiments, the acrylic monomer containing aldehyde and/or ketone functional groups is present in an amount of from 0.1 to 20 weight percent, such as from 1 to 20 weight percent, or sometimes, from 1 to 10 weight percent, based on the total weight of the reactants used to prepare the acrylic copolymer resin particles.
As used herein, the term "hydrophobic acrylic monomer" refers to a water-insoluble acrylic monomer. Examples of hydrophobic acrylic monomers, both of which are used in the compositions of the present invention, are (i) a (meth) acrylic acid ester of an alkyl alcohol, wherein the alkyl portion of the alcohol is straight or branched chain and contains at least 4 carbon atoms, and (ii) styrenic monomers. Sometimes, the hydrophobic acrylic monomers used in the present invention consist essentially of, or sometimes are only, styrenic monomers and (meth) acrylic esters of alkyl alcohols, wherein the alkyl portion of the alcohol is linear or branched and contains at least 4 carbon atoms.
In the coating composition of the present invention, the hydrophobic acrylic monomer content is at least 50 weight percent, such as at least 60 weight percent, at least 70 weight percent, at least 80 weight percent, at least 85 weight percent, or sometimes at least 90 weight percent, based on the total weight of the reactants used to prepare the acrylic copolymer resin particles. In certain embodiments, the hydrophobic acrylic monomer content is no more than 99 weight percent, such as no more than 95 weight percent, based on the total weight of reactants used to prepare the acrylic copolymer resin particles.
As used herein, the term "styrenic monomer" generally refers to aromatic hydrocarbon compounds (non-limiting examples include benzene, toluene, and naphthalene) that contain vinyl substituents. Non-limiting examples of styrenic monomers include those having from 8 to 18 carbon atoms per molecule, such as those having from 8 to 12 carbon atoms. Specific examples include, but are not limited to, styrene, p-methylstyrene, α -methylstyrene, t-butylstyrene, dimethylstyrene, 3-methylstyrene, 2-ethylstyrene, 3-ethylstyrene, 4-n-propylstyrene, 4-cyclohexylstyrene, 4-decylstyrene, 2-ethyl-4-benzylstyrene, 4- (4-phenyl-n-butyl) styrene, 1-vinylnaphthalene, 2-vinylnaphthalene, nuclear brominated or chlorinated derivatives thereof, and combinations thereof.
In the coating composition of the present invention, the styrenic monomer content is at least 60% by weight, such as at least 70% by weight, based on the total weight of the hydrophobic acrylic monomers used to prepare the acrylic copolymer resin particles. In certain embodiments, the styrenic monomer content is no more than 90 weight percent, such as no more than 80 weight percent, based on the total weight of hydrophobic acrylic monomers used to prepare the acrylic copolymer resin particles.
As used herein, "(meth) acrylate," and similar terms, are meant to encompass both acrylates and methacrylates. As noted, the hydrophobic acrylic monomer used to prepare the acrylic copolymer resin particles present in the coating compositions of the present invention comprises a (meth) acrylic acid ester of an alkyl alcohol, wherein the alkyl portion of the alcohol is linear or branched and contains at least 4 carbon atoms, such as 4 to 14 carbon atoms, 4 to 10 carbon atoms, or sometimes 4 to 8 or 6 to 8 carbon atoms. Specific examples of the above monomers suitable for use in the present invention include, but are not limited to, isooctyl acrylate, 4-methyl-2-pentyl acrylate, 2-methylbutyl acrylate, isopentyl acrylate, sec-butyl acrylate, n-butyl acrylate, 2-ethylhexyl acrylate, isodecyl methacrylate, isononyl acrylate, isodecyl acrylate, and the like, including mixtures thereof.
In certain embodiments of the coating compositions of the present invention, the hydrophobic alkyl (meth) acrylate is present in an amount of at least 10 weight percent, such as at least 20 weight percent, based on the total weight of hydrophobic acrylic monomers used to prepare the acrylic copolymer resin particles. In certain embodiments, the hydrophobic alkyl (meth) acrylate is present in an amount of no more than 40 weight percent, such as no more than 30 weight percent, based on the total weight of hydrophobic acrylic monomers used to prepare the acrylic copolymer resin particles.
In certain embodiments, the acrylic copolymer resin particles included in the coating compositions of the present invention are the reaction product of reactants other than those described above. For example, in certain embodiments, the reactants further comprise a phosphate-functional monomer, i.e., an acrylic monomer with phosphate functionality. Examples of such monomers include phosphoethyl (meth) acrylate and polymerizable phosphate compounds having the formula:
R1-C(O)-R2-OPO3H2
the disclosure of which is in U.S. patent US 6,534,597 at column 2, lines 30-46, the citation of which is incorporated herein by reference.
Suitable phosphate-functional monomers are also commercially available and include those sold by Rhodia as SIPOMERPAM-100.
In certain embodiments of the coating compositions of the present invention, the phosphate-functional monomer is present in an amount of at least 0.1 weight percent, such as at least 0.5 weight percent, based on the total weight of acrylic monomers used to prepare the acrylic copolymer resin particles. In certain embodiments, the phosphate-functional monomer content is no more than 5 weight percent, such as no more than 2 weight percent, based on the total weight of acrylic monomers used to prepare the acrylic copolymer resin particles.
Other suitable monomers for preparing the acrylic copolymer resin particles include hydrophilic monomers, i.e., water-soluble monomers, and partially hydrophilic monomers. Specific examples include, but are not limited to, acrylic acid, methacrylic acid, fumaric acid, maleic acid, itaconic acid, crotonic acid, acrylic oligomers, 2-hydroxyethyl acrylate, (meth) acrylic acid esters of alkyl alcohols having 1-2 carbon atoms in the alkyl portion, such as methyl (meth) acrylate, ethyl (meth) acrylate, N-vinyl-2-pyrrolidone, and mixtures thereof.
If used, the amount of the above-described hydrophilic and/or partially hydrophilic monomers used to prepare the acrylic copolymer resin particles is generally not more than 2% by weight, such as not more than 1% by weight, or sometimes, not more than 0.5% by weight, based on the total weight of the acrylic monomers used to prepare the acrylic copolymer resin particles.
In certain embodiments, the acrylic copolymer particles have a weight average molecular weight (Mw) in the range of, for example, 10,000-1,000,000 g/mole, such as 50,000-500,000, or sometimes 50,000-200,000 g/mole, as determined by gel permeation chromatography using polystyrene standards.
In certain embodiments, the acrylic copolymer particles have a calculated Tg of at least 40 ℃, or sometimes at least 45 ℃. In certain embodiments, the acrylic copolymer particles have a Tg of no more than 70 ℃, such as no more than 60 ℃, or sometimes no more than 55 ℃. In certain embodiments, the acrylic copolymer particles have an acid number of less than 5, such as less than 4. As used herein, the "calculated Tg" of a polymer refers to the Tg of the theoretical polymer formed from the selected monomers, in their selected amounts, as disclosed in the "chemical content of organic film formers", d.h. solomon, j.wiley & Sons, new york, 1967, page 29.
If acid functional groups are present in the acrylic copolymer particles, they may be neutralized using, for example, an amine, such as dimethylethanolamine, ammonia, triethanolamine, dimethylethanolamine or N ', N' -dimethylaminopropylamine, or an alkali metal salt such as sodium or potassium hydroxide.
The emulsion comprising the above acrylic copolymer particles dispersed in the aqueous continuous phase may be prepared, for example, by latex emulsion polymerization of the above polymerizable reactants. In certain embodiments, the aqueous continuous phase is added with a surfactant to stabilize or prevent agglomeration or clumping of the monomer droplets, particularly during polymerization.
The surfactant may be present in the latex emulsion in any concentration that stabilizes the emulsion. The surfactant is present in an amount of at least 0.001 wt%, often at least 0.005 wt%, at least 0.01 wt%, or at least 0.05 wt%, based on the total weight of the latex emulsion. The surfactant content is at least not greater than 10 wt%, often sometimes not greater than 7.5 wt%, not greater than 5 wt%, or sometimes not greater than 3 wt%, based on the total weight of the latex emulsion. The use concentration of the surfactant is determined by the amount required to stabilize the latex emulsion.
The surfactant may be an anionic, cationic, or nonionic surfactant or dispersant, or a compatible mixture thereof, such as a mixture of anionic and nonionic surfactants. Suitable cationic dispersants that can be used include, but are not limited to, pyridinium lauryl chloride, cetyl dimethylamine acetate, and alkyl dimethyl benzyl ammonium chloride, wherein the alkyl group has from 8 to 18 carbon atoms.
Suitable anionic dispersants include, but are not limited to, alkali metal fatty alcohol sulfates such as sodium lauryl sulfate and the like, arylalkyl sulfonates such as potassium cumene sulfonate and the like, alkyl succinate alkali metal sulfonates such as sodium octyl succinate sulfonate and the like, and alkali metal arylalkyl polyethoxyethanol sulfates or sulfonates such as sodium octylphenoxy polyethoxyethyl sulfate having from 1 to 5 ethoxy units and the like.
Suitable specific examples of anionic surfactants include sodium dodecyl sulfate (Dupont C or QC, DuPont), mixed long chain alcohol sodium sulfate, obtained from Du Pont under the name Dupont WN, octyl sodium sulfate, obtained from Alcolac, Ltd. under the name Sipex OLS, sodium trideceth sulfate (Sipex EST), sodium lauryl ether sulfate (Sipon ES), magnesium lauryl sulfate (Sipon LM), ammonium lauryl sulfate (Sipon L-22), diethanol amino lauryl sulfate (Sipon LD), sodium dodecylbenzenesulfonate (sodium dodecylbenzenesulfonate), (Sipon LD)DS), sodium laureth sulfate, magnesium laureth sulfate, sodium laureth-8 sulfate, magnesium laureth-8 sulfate mixture sold by Cognis under the name Texapon ASV, sodium laureth sulfate (C)12-1470/30) (2.2EO), sold by Cognis under the name Sipon AOS 225 or Texapon N702 Pase, ammonium laureth sulfate (C)12-1470/30) (3EO), sold by Cognis under the name Sipon Lea 370, and/or (C)12-14) Ammonium alkyl polyoxyethylether (9EO) sulfate sold under the name RhodapexAB/20 by Rhodia Chimie.
Reactive surfactants are suitable, often in combination with one or more of the above anionic surfactants. Examples of such reactive emulsifiers include, but are not limited to, reactive anionic surfactants, sulfosuccinate reactive anionic surfactants, and alkenyl succinate reactive anionic surfactants. Examples of commercially available sulfosuccinate reactive anionic surfactants are LATEMUL S-120, S-120A, S-180 and S-180A (trade name, product Kao Corp.) and ELEMINOL JS-2 (trade name, product of Sanyo chemical industries, Ltd.). An example of a commercially available alkenyl succinate reactive anionic surfactant is LATEMUL ASK (trade name, Kao Corp. product).
Another suitable reactive surfactant is C3-5Aliphatic unsaturated carboxylic acid alkyl sulfonate (containing 1 to 4 carbon atoms) ester surfactants, for example, alkyl (meth) acrylate sulfonate ester surfactants such as sodium sulfoethyl 2- (meth) acrylate and ammonium 3-sulfopropyl (meth) acrylate, and alkyl dialkyl aliphatic unsaturated dicarboxylic acid sulfonate ester surfactants such as sodium sulfopropyl (alkyl) maleate, ammonium sulfopropyl (polyethylene oxide alkyl) maleate and ammonium sulfoethyl (polyethylene oxide alkyl) fumarate, diethylene glycol alkylphenol ether sulfate maleate, dihydroxyethyl (meth) acrylate sulfate, 1-allyloxy-3-alkylphenoxy-2-polyethylene oxide sulfate (trade name: ADEKA soap true-10N, product of ADEKA corp.), polyethylene oxide alkylalkenylphenol sulfate (trade name: AQUALON, DAI-ICHI KOGYOSEIYAKU co., ltd. product), and ADEKA-soap SR-10(EO mole =10, product of ADEKA corp.), SR-20(EO mole =20, product of ADEKA corp.), and SR-30(EO mole =30, product of ADEKA corp.).
Free radical initiators are often used in the latex emulsion polymerization process. Any suitable free radical initiator may be used. Suitable free radical initiators include, but are not limited to, high temperature initiators, photoinitiators, and redox initiators, all of which may be otherwise classified as either water soluble initiators or water insoluble initiators.
Examples of high temperature initiators include, but are not limited to, azo compounds, peroxides, and persulfates. Suitable persulfates include, but are not limited to, sodium persulfate and ammonium persulfate. Non-limiting examples of redox initiators that may be included are persulfate-sulfite systems and systems that use high temperature initiators in combination with a suitable metal ion such as iron or copper.
Suitable azo compounds include, but are not limited to, water-insoluble azo compounds such as 1-1' -azobiscyclohexanecarbonitrile, 2-2' -azobisisobutyronitrile, 2-2' -azobis (2-methylbutyronitrile), 2-2' -azobis (propionitrile), 2-2' -azobis (2, 4-dimethylvaleronitrile), 2-2' -azobis (valeronitrile), 2- (carbamoylazo) -isobutyronitrile, and mixtures thereof, and water-soluble azo compounds such as azobis (di-tert-alkyl) compounds including, but not limited to, 4-4' -azobis (4-cyanovaleric acid), 2-2' -azobis (2-methylpropionamidine) dihydrochloride, 2,2' -azobis [ 2-methyl-N- (2-hydroxyethyl) propionamide ],4,4 '-azobis (4-cyanovaleric acid), 2,2' -azobis (N, N '-dimethyleneisobutyramidine), 2,2' -azobis (2-amidinopropane) dihydrochloride, 2,2 '-azobis (N, N' -dimethyleneisobutyramidine) dihydrochloride, and mixtures thereof.
Suitable peroxides include, but are not limited to, hydrogen peroxide, methyl ethyl ketone peroxide, benzoyl peroxide, di-t-butyl peroxide, di-t-amyl peroxide, cumene peroxide, diacyl peroxide, decanol peroxide, lauroyl peroxide, peroxydicarbonate, peroxyester, dialkyl peroxide, hydroperoxide, peroxyketal, and mixtures thereof.
Further, the examples herein illustrate suitable conditions for preparing emulsions comprising the acrylic copolymer resin particles described herein.
As noted, the coating compositions of the present invention also include a crosslinker comprising at least two functional groups reactive with the carbonyl functional groups of the acrylic copolymer. In certain embodiments, the crosslinking agent is added to the emulsion during or after formation of the aforementioned acrylic copolymer resin particles.
Any nitrogen-containing compound having at least two amine nitrogens reactive with carbonyl groups may be used as the crosslinking agent. The above-mentioned crosslinking agent may be aliphatic or aromatic, polymeric or non-polymeric, and may be used singly, in combination of two or more. Non-limiting examples of suitable crosslinking agents include compounds comprising at least two hydrazide groups, i.e., NH2A group. Specific examples of the above compounds are disclosed in U.S. Pat. No. 10 line 12 to column 11 line 26 of U.S. Pat. No. 4,7,115,682, the citation being incorporated in its entiretyIncorporated herein by reference.
In certain embodiments, the crosslinking agent is present in the composition in an amount such that the number of functional groups, such as hydrazide groups, reactive with the carbonyl functional groups of the acrylic polymer ranges from 0.02 to 5 equivalents, such as 0.1 to 3 equivalents, or sometimes 0.5 to 2 equivalents, per equivalent of carbonyl groups contained in the acrylic copolymer.
In certain embodiments, the emulsion comprising the acrylic copolymer resin particles and the crosslinking agent described above is a relatively low viscosity material. The emulsions can be prepared directly to a total solids content of 20% to 70%, such as 30 to 50%. In certain embodiments, the above emulsions have a Gardner-Holdt bubble viscosity (bubble viscocity) of from "A" to "H".
In the coating composition of the present invention, after the composition is applied to a substrate and when water in the emulsion is evaporated, the hydrazide group and the carbonyl group are crosslinked due to dehydration condensation to form a cured film.
In certain embodiments, the coating compositions of the present invention further comprise a colorant. As used herein, the term "colorant" 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 composition of the present invention.
Examples of colorants include pigments, dyes, and stains such as those used in the paint industry and/or the Dry Color Manufacturers Association (DCMA) list, 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 agglomerated or non-agglomerated. Colorants can be incorporated into coatings 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 components include, but are not limited to, carbazole dioxazine primary pigments, azo, monoazo, disazo, naphthol AS, salt types (lakes), benzimidazolones, condensates, metal complexes, isoindolinones, isoindolines, and polycyclic phthalocyanines, quinacridones, perylenes, perinones, diketopyrrolopyrroles, thioindigo, anthraquinones, indanthrones, anthrapyrimidines, flavanthrones, pyranthrones, anthanthrones, dioxazines, triarylcarboniums, quinophthalone pigments, diketopyrrolopyrrole reds ("DPPBO reds"), titanium dioxide, carbon black, and mixtures thereof. The terms "pigment" and "colored filler" may be used interchangeably.
Examples of dyes include, but are not limited to, those based on solvents and/or aqueous such as phthalocyanine green or blue, iron oxide, bismuth vanadate, anthraquinone, perylene, aluminum, and quinacridone.
Examples of coloring agents include, but are not limited to, pigments dispersed in aqueous or water-soluble carriers such as AQUA-CHEM 896, commercially available from Degussa, Inc., CHARISMA COLORANTS and MAXITORER INDUSTRIAL COLORANTS, commercially available from the AccurateDispersions division, Eastman Chemical, Inc.
As noted above, the 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 150 nanometers, such as less than 70 nanometers, or less than 30 nm. The nanoparticles may be prepared by comminuting organic or inorganic pigments with an abrasive having a particle size of less than 0.5 mm. Examples of nanoparticle dispersions and methods for their preparation are disclosed in U.S. Pat. No. 6,875,800B2, the disclosure of which is incorporated herein by reference. Nanoparticle dispersions can also be prepared by crystallization, precipitation, gas phase agglomeration, and chemical abrasion (i.e., partial dissolution). To minimize re-agglomeration of nanoparticles within the coating, resin-coated nanoparticle dispersions may be used. As used herein, "dispersion of resin-coated nanoparticles" refers to "composite particles" that are discretely distributed in a continuous phase. The composite particles comprise nanoparticles and a resin coated on the nanoparticles. Examples of resin-coated nanoparticle dispersions and methods for their preparation are disclosed in U.S. patent application publication No. 2005-0287348a1, filed 24.6.2004, U.S. provisional application publication No. 60/482,167, filed 24.6.2003, and U.S. patent application publication No. 11/337,062, filed 20.1.2006, which are also incorporated herein by reference.
Special effect composition examples pigments and/or components that may be used in the coating compositions of the present invention produce one or more appearance effects such as reflectance, pearl powder, metallic sheen, phosphorescence, fluorescence, photochromism, photosensitivity, thermochromism, high goniochromity (goniochromity), and/or discoloration. Additional special effect components may provide other visual traits such as opacity or texture. In certain embodiments, special effect components 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 components are disclosed in U.S. Pat. No. 6,894,086, the disclosure of which is 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 composition wherein interference results from a refractive index difference within the material and not from a refractive index difference between the surface of the material and air.
In certain embodiments, photosensitive components and/or photochromic components that reversibly change color when exposed to one or more light sources may be used in the coating compositions of the present invention. The photochromic and/or photosensitive component can be activated by exposure to radiation of a particular wavelength. If the composition is excited, the molecular structure changes and the altered structure exhibits a new color that is different from the original color of the component. When the exposure to radiation is removed, the photochromic and/or photosensitive component can return to a quiescent state, wherein the component returns to the original color. In certain embodiments, the photochromic and/or photosensitive component can be colorless in a non-excited state and exhibit an excited state color. Full color-change can be manifested within milliseconds to minutes, such as 20 seconds to 60 seconds. Examples of photochromic and/or photosensitive components include photochromic dyes.
In certain embodiments, the photosensitive component and/or photochromic component can be linked and/or at least partially bound, such as by covalent bonds, to the polymer and/or polymeric material of the polymerizable component. In contrast to some coatings in which the photosensitive component can migrate out of the coating and crystallize into the substrate, the amount of photosensitive component and/or photochromic component attached to and/or at least partially bound to the polymer and/or polymerizable component migrates out of the coating is minimized according to certain embodiments of the present invention. Examples of photosensitive and/or photochromic components and methods for their preparation are disclosed in U.S. patent application US 2006-0014099A1, the disclosure of which is incorporated herein by reference.
Generally, the colorant is present in the coating composition in an amount sufficient to impart the desired visual and/or color effect. The colorant may comprise from 1 to 65 weight percent, such as from 3 to 40 weight percent or from 5 to 35 weight percent of the composition of the present invention, with weight percent being based on the total weight of the composition.
The coating composition of the present invention may further comprise other optional functional components such as organic solvents, defoamers, pigment dispersants, plasticizers, ultraviolet absorbers, antioxidants, surfactants, and the like. These optional functional components, if present, are generally present in an amount of no greater than 30 percent based on the total weight of the coating composition.
In certain embodiments, the acrylic copolymer resin particles present in the coating compositions of the present invention do not contain an inner layer and an outermost layer as disclosed in U.S. patent nos. 5,447,970 and 5,472,996. In certain embodiments, the coating compositions of the present invention are substantially free, or sometimes completely free, of monoketones and monoaldehydes, as disclosed in U.S. patent No. US4,786,676. In certain embodiments, the coating compositions of the present invention are substantially free, or sometimes completely free, of heavy metal ions, such as disclosed in U.S. patent No. US4,259,070. In certain embodiments, the coating compositions of the present invention are substantially free or, in some cases, completely free of any polyurethane resin.
As used herein, the term "substantially free" means that when used in reference to a raw material that is substantially absent from a coating composition, the raw material is present, if at all, as incidental impurities. In other words, the raw materials do not affect the properties of the coating composition. As used herein, the term "completely free" means that no raw materials are present in the composition at all.
The coating composition of the present invention can be prepared by any method known to those of ordinary skill in the art using the above components as raw materials. Suitable methods are disclosed in the examples of the present application.
The invention also relates to a method for using the coating composition. These methods comprise applying the coating composition to the surface of a substrate or article to be coated, coalescing the composition to form a substantially continuous film and then curing the film.
The coating compositions of the present invention are suitable for coating any of a variety of substrates, including human and/or animal substrates such as cutin, fur, skin, teeth, nails, and the like, as well as plants, trees, seeds, agricultural areas such as rangelands, croplands, and the like, turf-covered areas, e.g., grass, golf courses, athletic fields, and the like, and other land areas such as forests and the like. One particular advantage of the coating compositions of the present invention is indeed their ability to adhere to a wide variety of substrates, both metal and plastic, while exhibiting other desirable properties such as resistance and humidity resistance.
Suitable substrates include cellulose-containing materials including paper, paperboard, cardboard, plywood, and pressed fiberboard, hardwood, softwood, wood veneer, particleboard, particle board, oriented strand board, and fiberboard. The above materials may be made entirely of wood such as pine, oak, light brown, mahogany, cherry, and the like. However, sometimes the material may comprise wood in combination with another material, such as a resinous material, i.e. a wood/resin composite, such as a phenolic composite, a composite of wood fibres and a thermoplastic polymer, and a composite of wood reinforced with cement, fibres, or plastics veneers.
Suitable metal substrates include, but are not limited to, sheet, or cold rolled steel, stainless steel, and steel treated on the surface with any of zinc metal, zinc compounds, and zinc alloys (including electrogalvanized steel, hot-dip galvanized steel, galvaneal steel, and zinc alloy-coated steel), copper, magnesium, and alloys thereof, workpieces made from zinc-aluminum alloys such as GALFAN, GALVALUME, and aluminum-coated steel and aluminum alloy-coated steel substrates may also be used. Weldable, zinc-rich or iron phosphide-rich organic coatings coated on steel substrates, such as cold rolled steel or any of the above listed steel substrates, are also suitable for use in the process of the present invention. Weldable coating compositions as described above are disclosed in, for example, U.S. Pat. nos. 4,157,924 and 4,186,036. In addition, cold rolled steel is also suitable if it is pretreated with, for example, a solution selected from the group consisting of metal phosphate solutions, aqueous solutions containing at least one group IIIB or group IVB metal, organophosphate solutions, organophosphonate solutions, and combinations thereof. In addition, suitable metal substrates include silver, gold, and alloys thereof.
Examples of suitable silicate substrates are glass, porcelain and ceramic.
Examples of suitable polymeric substrates are polystyrene, polyamides, polyesters, polyethylene, polypropylene, melamine resins, polyacrylates, polyacrylonitrile, polyurethanes, polycarbonates, polyvinyl chloride, polyvinyl alcohol, polyvinyl acetate, polyvinylpyrrolidone and corresponding copolymers and block copolymers, biodegradable polymers and natural polymers such as gelatin.
Examples of suitable textile substrates are fibers, filaments, threads, knits, fabrics, nonwovens and garments composed of polyester, modified polyester, polyester blend fabrics, nylon, cotton blend fabrics, jute fibers, flax fibers, hemp fibers and ramie fibers, viscose fibers, wool, silk, polyamides, polyamide blend fabrics, polyacrylonitrile, triacetate fibers, acetate fibers, polycarbonate fibers, polypropylene, polyvinyl chloride, polyester microfibers and glass fiber fabrics.
Examples of suitable leather substrates are suede leather (e.g. nappa gloveshes from sheep, goat or cow, and box-leather from calf or cow), suede leather (e.g. velour from sheep, goat or cow, and suede leather), split velours (e.g. from cow or calf skin), buckskin and suede leather, furthermore sheds and beasts (e.g. fur-suede leather). The leather may be tanned by any conventional tanning method, especially vegetable, mineral, synthetic or combination tanned (e.g. chrome tanned, zirconyl tanned, aluminum tanned or semi-chrome tanned). If desired, the leather can also be retanned, and for retanning any of the tanning agents conventionally used for retanning, for example mineral, vegetable or synthetic tanning agents, such as chromium, zirconyl or aluminum derivatives, quebracho, chestnut or wattle bark extracts, aromatic syntans, polyurethanes, (co) polymers of (meth) acrylic compounds or resins of melamine, dicyandiamide and/or urea-formaldehyde, can be used.
In certain embodiments, the coating compositions of the present invention are suitable for application to "flexible" substrates. As used herein, the term "flexible substrate" refers to a substrate that can be subjected to mechanical stress, such as bending or stretching, without significant irreversible change. In certain embodiments, the flexible substrate is a compressible substrate. "compressible substrate" and like terms refer to a substrate that is capable of undergoing compressive deformation and returning to substantially the same shape once compressive deformation ceases. The term "compressive deformation" and similar terms mean that mechanical stress causes a reduction in the volume of the substrate, at least temporarily, in at least one direction. Examples of flexible substrates include non-rigid substrates such as fiberglass woven and nonwoven, glass woven and nonwoven, polyester woven and nonwoven, Thermoplastic Polyurethane (TPU), synthetic leather, natural leather, processed synthetic leather, foams, air, liquid, and/or plasma filled polymer bladders, polyurethane elastomers, chemical fibers, and natural textiles. Examples of suitable compressible substrates include foam substrates, liquid-filled polymer bladders, air and/or gas-filled polymer bladders, and/or plasma-filled polymer bladders. The term "foam substrate" as used herein refers to a polymeric or natural material comprising an open cell foam and/or a closed cell foam. As used herein, the term "open cell foam" means that the foam comprises a plurality of interconnected air chambers. As used herein, the term "closed cell foam" means that the foam comprises a series of discrete closed cells. Examples of foam substrates include, but are not limited to, polystyrene foams, polyvinyl acetate and/or copolymers, polyvinyl chloride and/or copolymers, poly (meth) acrylamide foams, polyvinyl chloride foams, polyurethane foams, and polyolefin foams and polyolefin blends. Polyolefin foams include, but are not limited to, polypropylene foams, polyethylene foams, and ethylene vinyl acetate ("EVA") foams. EVA foam includes flat sheets or plates or molded EVA foam, such as shoe midsoles. Different types of EVA foam have different types of surface porosity. Molded EVA may comprise a dense surface or "skin" while a flat sheet or plate may exhibit a porous surface. "textile" may include natural and/or synthetic textiles such as fabrics, vinyl and polyurethane coated fabrics, meshes, nets, ropes, filaments etc. and may be of a composition such as canvas, cotton, polyester, KELVAR, polymer fibres, polyamides such as nylon etc, polyesters such as polyethylene terephthalate and polybutylene terephthalate etc, polyolefins such as polyethylene and polypropylene etc, rayon, polyethylene polymers such as polyacrylonitrile etc, other fibrous materials, cellulosic plastics materials etc.
The coating compositions of the present invention have a wide variety of applications. For example, because the coating compositions of the present invention produce coatings that adhere well to both plastic and metal substrates, and because they are water-resistant and alcohol-resistant (as described below), they are particularly useful for articles made from such substrates and their potential exposure to water and alcohol over significant substrates. Specific examples of such articles are, without limitation, medical devices such as diagnostic, patient monitoring and analytical instruments including magnetic resonance imaging, nuclear medicine, computed tomography, ultrasound, X-ray, and general direct single coating of plastics or metals (commercial computer or structural steel markets).
The coating composition of the present invention can be applied to the above-mentioned substrate by any of various methods including spraying, brushing, dipping, and roll coating, among others. However, in certain embodiments, the coating compositions of the present invention are applied by spray application, and such compositions typically correspond to viscosities suitable for spray application at ambient conditions.
After applying the coating composition of the present invention to the substrate, the composition is coalesced to form a substantially continuous film on the substrate. Typically, the film thickness is from 0.01 to 20 mils (about 0.25 to 508 microns), such as from 0.01 to 5 mils (0.25 to 127 microns), or sometimes, from 0.1 to 2 mils (2.54 to 50.8 microns) thick. The coating compositions of the present invention may be colored or clear and may be used alone or in combination as a primer, basecoat, or topcoat.
The coating composition of the present invention cures in the presence of ambient air at an air relative humidity of 10-100%, such as 25-80%, and a temperature in the range of-10 to 120 ℃, such as 5 to 80 ℃, sometimes 10-60 ℃ and in other cases 15-40 ℃ and can provide a film with excellent early performance in a relatively short period of time, which allows coating of objects without detrimental effect on the appearance of the coating film and which finally cures into a film exhibiting excellent hardness, solvent resistance and impact resistance.
The coating compositions of the present invention have been shown to produce cured coatings that are both water and alcohol resistant, which is particularly important in certain applications, such as when the coating compositions are used in medical devices (and other things) that are often exposed to such materials.
The following examples illustrate the invention and are not to be construed as limiting the invention to their detailed description. All parts and percentages in this example and throughout this specification are by weight unless otherwise indicated.