MXPA99005159A - Acrylic-melamine-functionalized oligomer coating composition - Google Patents

Abstract

An improved coating composition having particularly good mar resistance when applied to an automotive surface, the composition comprising acrylic polymer(s), melamine, and a cross-linkable, aliphatic oligomer having a weight average molecular weight not exceeding about 2,500.

Description

COMPOSITION OF NON-AQUEOUS COATING COMPRISES A RETICULABLE OLIGOMER BACKGROUND OF THE INVENTION The present invention relates to a curable coating composition particularly useful as a final coat of paint in multi-layer coating systems. The basecoat-transparent coating systems have found wide acceptance in the past decade in automotive finishes. A continuous effort has been directed to such coating systems to improve the overall appearance, the transparency of the final paint layer and the resistance to deterioration. Further efforts have been directed to the development of coating compositions having a low content of volatile organic substances (VOC) There is a continuing need for coating formulations which provide a surprising balance of performance characteristics after application, particularly resistance to usual wear. Until now, the usual wear resistant coatings are obtained by softening the coating, which detracts from other performance characteristics. The present invention solves this problem and is an improvement REF .: 30141 of the coating composition described in U.S. 4,591,533.

BRIEF DESCRIPTION OF THE INVENTION In a coating composition which, when dry, has measurable values of usual hardness and wear resistance, comprising an organic liquid carrier and a film-forming binder consisting of: (i) an acrylic polymer, I, of monomers which are selected from the group consisting of alkyl methacrylate, alkyl acrylate, hydroxyalkyl acrylate and hydroxyalkyl methacrylate; the polymer has an average molecular weight weight of about 3,000 to 20,000; (ii) a self-stabilized dispersed resin formed by polymerizing the following constituents: (a) an acrylic polymer, II, of monomers that are selected from the group consisting of alkyl methacrylate, alkyl acrylate, hydroxyalkyl acrylate, hydroxyalkyl methacrylate and acid ethylenically unsaturated carboxylic acid; the polymer has an average molecular weight weight of about 3,000 to 20,000; and (b) monomers that are selected from the group consisting of alkyl methacrylate, alkyl acrylate, hydroxyalkyl acrylate, and hydroxyalkyl methacrylate; wherein the acrylic polymer, II, is also derived from a monomer selected from the group consisting of glycidyl methacrylate, glycidyl acrylate, glycidyl methacrylate post-reacted with carboxylic acid and glycidyl acrylate post-reacted with carboxylic acid; and (iii) an alkylated melamine and formaldehyde crosslinking agent; the improvement is characterized in that it comprises replacing at least 5% by weight of (i) with at least one crosslinkable aliphatic oligomer having an average molecular weight not exceeding 2,500; whereby the usual wear resistance of the resulting dry coating is improved to at least about 85 percent, as measured by the "rub-rub test", while maintaining a hardness value of at least about 9 knoop.

The preferred oligomer substitution for the acrylic component (I) is an epsilon adduct caprolactone (6-hexanolactone, 2-oxepanone), 1,3,5-tris (2-hydroxyethyl) -cianuric acid. This adduct is referred to in the following as the "caprolactone adduct". The preferred substitution oligomer has an average molecular weight weight of 500 to 1500. A preferred embodiment of this invention is to prepare a substantially colorless coating composition by adding from 0.1 to 2 percent of a phosphorus-containing compound such as 9, 10-dihydro-9-oxa-10-phosphafenanthren-10-oxide and / or triphenyl phosphite, by weight of the oligomeric adduct solids. Other polyhydroxyl oligomers may be used in place of all or part of the caprolactone adduct and a person familiar in the art will know how to select such an oligomer or oligomers based on the teachings provided herein. For example, the adducts which can be used are polyester reaction products of a multifunctional alcohol such as pentaerythritol, trimethylolpropane, hydrogenated bisphenol A, hexanediol or cyclohexane dimethanol, which reacts with a monomeric anhydride such as hexahydrophthalic anhydride, the reaction product furthermore reacts with a monofunctional epoxy (oxirane) such as butylene oxide, propylene oxide or the like.

The term "aliphatic" is used herein to include aliphatic and cycloaliphatic materials. The term "crosslinkable" means that the individual components of the adduct contain functionality which reacts within the composition of the invention to provide a coating of good appearance, durability, hardness and wear resistance. The functionalities of average components are greater than 1, preferably greater than 2. In the preferred compositions, the substitution adducts comprise proportions of lactone to isocyanurate of 6: 1 to 1: 2, preferably 3-5: 1; more preferably from 4.1. In example 1 the "friction-abrasion test" is defined.

DETAILS OF THE INVENTION The coating composition has a film-forming binder content of about 20-85% by weight and correspondingly about 15-80% by weight of a liquid carrier. Preferably, the coating composition is a high solids composition containing about 50-80% by weight of the binder and 20-50% by weight of organic solvent for the binder. The binder of the composition is preferably a mixture of about 5-75% by weight of an acrylic polymer I, and 5-45% by weight of a self-stabilized dispersed resin, and 20-50% by weight of a melamine crosslinking agent. alkylated and formaldehyde. The acrylic polymer I is of polymerized monomers of an alkyl methacrylate, an alkyl acrylate, a hydroxyalkyl acrylate or methacrylate and has an average molecular weight weight of about 3,000-20,000. Preferably, styrene is used with the above monomers in acrylic polymer I. Typical alkyl methacrylate used to form the acrylic polymer is methyl methacrylate, ethyl methacrylate, propyl methacrylate, butyl methacrylate, isobutyl methacrylate, pentyl methacrylate , hexyl methacrylate, octyl methacrylate, nonyl methacrylate, lauryl methacrylate and the like. Acrylates used to form the acrylic polymer Typical alkyl acrylate are methyl acrylate, ethyl acrylate, propyl acrylate, butyl acrylate, isobutyl acrylate, pentyl acrylate, hexyl acrylate, octyl acrylate, nonyl acrylate, lauryl and the like. The acrylates and methacrylates are typical hydroxyalkyl acrylate, hydroxypropyl acrylate, hydroxyisopropyl acrylate, hydroxybutyl acrylate, hydroxyethyl methacrylate, hydroxypropyl methacrylate, hydroxyisopropyl methacrylate, hydroxybutyl methacrylate and the like, and mixtures of the above monomers.

Preferably, the acrylic polymer I is composed of 5-30% by weight of butyl acrylate, 15-50% by weight of hydroxyethyl acrylate or hydroxypropyl acrylate and has a weight average molecular weight of about 5,000-15,000. Optionally, the polymer may contain about 0.1-5% by weight of acrylic acid or methacrylic acid. The acrylic polymer I is prepared by solution polymerization in which the monomers, conventional solvents, polymerization initiators such as peroxyacetate are heated at about 90-250 ° C for 1-6 hours. The self-stabilized dispersed resin is formed by polymerizing the following constituents in solution: (1) an acrylic polymer II; (2) monomers of alkyl acrylate, alkyl methacrylate and hydroxy acrylate or methacrylate. Conventional solvents and polymerization initiators such as t-butyl peracetate are used. The constituents are heated to about 80-250 ° C for about 1-6 hours to form the resin. The acrylic polymer II solution consists of polymerized monomers of alkyl methacrylate, alkyl acrylate, hydroxyalkyl acrylate or methacrylate and an ethylenically unsaturated carboxylic acid and, optionally,, styrene monomers. Any of the alkyl acrylates, methacrylates, hydroxyalkyl acrylates or methacrylates mentioned above can be used to prepare the polymer. Typical ethylenically unsaturated carboxylic acids that can be used are acrylic acid and methacrylic acid. Preferably, styrene is used to form the polymer with the above monomers. A preferred polymer contains about 5-25% by weight of styrene, 20-40% by weight of butyl acrylate, 20-40% of butyl methacrylate, 5-15% by weight of hydroxyethyl acrylate, 1-5% by weight. weight of acrylic acid and 10-20% by weight of ethyl methacrylate, and has an average molecular weight of about 7,000-15,000. Another preferred polymer contains about 5-25% by weight of styrene, 25-35% by weight of butyl methacrylate, 20-40% by weight of butyl acrylate, 5-15% by weight of hydroxyethyl acrylate, 1-5 % by weight of acrylic acid, 10-20% by weight of ethyl methacrylate and 1-5% by weight of glycidyl methacrylate post-reacted with acrylic acid and has an average molecular weight of about 7,000-15,000. The conventional polymerization techniques are used as described above for the acrylic polymer I in order to prepare the acrylic polymer II. The methacrylate or glycidyl acrylate is post-reacted with the carboxyl groups of acrylic polymer II or is one of the monomers that is polymerized with acrylic polymer II. Any of the alkyl acrylates or methacrylates mentioned above can be used, ethylenically unsaturated acids are monomers that can be used to prepare the self-stabilized / dispersed resin. Other useful monomers are styrene, acrylonitrile, methacrylonitrile, acrylamide, methacrylamide, methacrylates, or perfluoroalkyl acrylates, dicarboxylic acids such as itaconic acid, and the like. Typical solvents and diluents are used to form the above polymers and the resulting coating composition. Suitable solvents are chosen to form polymer solutions or dispersions and the appropriate diluents are chosen to form coating compositions. Typical solvents and diluents are toluene, xylene, butyl acetate, acetone, methyl isobutyl ketone, methyl ethyl ketone, methanol, isopropanol, butanol, hexane, acetone, ethylene glycol monomethyl ether, naphtha, mineral spirits, heptane and other aliphatic, cycloaliphatic or aromatic hydrocarbons, esters, ethers and ketones. The crosslinking agents used in the composition is a fully alkylated melamine formaldehyde resin which is preferably a methylated and butylated melamine formaldehyde resin having a degree of polymerization of about 1-3. Generally this melamine and formaldehyde resin contains about 50% butylated groups and 50% methylated groups. Typically, these crosslinking agents have an average number of molecular weight of about 300-600 and an average molecular weight of about 500-1500. It is possible to use other alkylated melamine formaldehyde crosslinking agents. Typically, lower alkyl alcohols are used to form these crosslinking agents such as methanol, ethanol, propanol, isopropanol, butanol, isobutanol, hexanol and the like. In addition, urea formaldehyde, benzoguanamine formaldehyde and polyisocyanates can be used as crosslinking agents. A preferred coating composition contains: (i) about 5-75% by weight of a solution of a 5-50% by weight ratio of caprolactone; 50-95% by weight of acrylic polymer I which comprises 5-30% by weight of styrene, 10-40% by weight of butyl methacrylate, 10-40% by weight of butyl acrylate, 15-50% by weight of hydroxyethyl acrylate or hydroxypropyl acrylate; the polymer I has an average molecular weight weight of about 5,000-15,000; and (ii) 5-45% by weight of a self-stabilizing dispersion resin formed by polymerizing the following constituents. (a) an acrylic solution of polymer II consisting of 5-25% by weight of styrene, 20-40% by weight of butyl acrylate, 20-40% by weight of butyl methacrylate, 5-15% by weight of acrylate of hydroxyethyl, 1-5% by weight of acrylic acid, 10-20% by weight of ethyl methacrylate and having an average molecular weight of about 7,000-15,000, and (b) monomers of styrene, methyl methacrylate, hydroxyethyl acrylate, methacrylic acid, methyl acrylate and glycidyl methacrylate; wherein the carboxyl groups of the acrylic acid are subsequently reacted with glycidyl methacrylate, and (iii) 25-50% by weight of a melamine formaldehyde crosslinking agent completely methylated and butylated. Preferred adduct and oligomer substitutions in component (i) are typically maintained at about 50% or less.

Generally, an acid catalyst is used in the coating composition to improve the crosslinking of the curing components. Approximately 0.1-2% by weight can be used, based on the weight of the catalyst composition. Typically, blocked aromatic sulfonic acids are used. A preferred blocked acid catalyst is dodecylbenzenesulfonic acid with dimethyloxazolidine. Other acid catalysts which may be used are sulfonic acid, paratoluene sulfonic acid, dionyl naphne-sulfonic acid and the like. To improve the weatherability of the clear finish of the coating composition, approximately 0.1-5% by weight, based on the weight of the binder, of a light stabilizer, or a combination of ultraviolet light stabilizers, can be added. . These stabilizers include ultraviolet absorbing substances, filters, extinguishers and light stabilizers specific for hindered amine. In addition, approximately 0.1-5% by weight can be added based on the weight of the binder, of an antioxidant. Typical ultraviolet light stabilizers which are useful are the following: Benzophenones such as hydroxydecylbenzophenone, 2,4-dihydroxybenzophenone, hydroxybenzophenones containing sulfonic acid groups, 2,4-dihydroxy-3 ', 5'-di-t-butylbenzophenone, esters of 2,2-dicarboxylic acids, 2,4'-trihydroxybenzophenone, 2-hydroxy-4-acryloxyethoxybenzophenone, aliphatic monoesters of 2,2 ', 4-trihydroxy-4'-alkoxybenzophenone, 2-hydroxy-4-methoxy-2' -carboxybenzophenone; Triazoles such as 2-f-enyl-4- (2 ', 4'-dihydroxybenzoyl) triazoles, substituted benzotriazoles such as hydroxyphenyltriazoles such as 2- (2'-hydroxy-5'-methylphenylbenzotriazole, 2- (2'-hydroxyphenyl) benzotriazole 2- (2'-Hydroxy-5'-octylphenyl) -naphthotriazole; Triazines such as 3,5-dialkyl-4-hydroxyphenyl triazine derivatives, sulfur-containing derivatives of dialkyl-4-hydroxyphenyl-triazines, hydroxyphenyl-1, 3, 5-triazines and triazines such as containing sulfonic acid, aryl-1, 3, 5-triazines, ortho-hydroxyaryl-triazine groups; Benzoates such as dibenzoate or diphenylolpropane, t-butyl benzoate or diphenylolpropane, benzoate of nonylphenyl, octylphenyl benzoate, resorcinol dibenzoate Other ultraviolet light stabilizers which may be used include lower alkyl thiomethylene containing phenols, substituted benzenes such as 1,3-bis (2'-hydroxybenzoyl) benzene, metal derivatives of 3,5-di-t.-butyl-4-hydroxy acid phenylpropionic, asymmetric oxalic acid diarylamides, esters of alkylhydroxyphenylthioalkanoic acid, esters of dialkylhydroxyphenylalkanoic acid of di and tri-pentaerythritol, diamides of oxalic acid substituted by phenyl and naphthalene, methyl-β- (3,5-di-t-butyl-4) -hydroxyphenyl) -propionate, a, a-bis (2-hydroxyphenyl) diisopropylbenzene, 3,5'-dibromo-2'-hydroxyacetophenone, 4,4-bis (4'-hydroxyphenyl) pentanoic acid ester derivatives where at least one unsubstituted position ortho to the aromatic hydroxyl groups, organophosphorus sulfides such as bis (diphenylphosphinothioyl) monosulfide and bis (diphenylphosphinothioyl) disulfide, 4-benzoyl-6- (dialkylhydroxybenzyl) resorcinol, bis (3-hydroxy-4) -benzoylphenoxy) diphenylsilane, bis (3-hydroxy-4-benzoylphenoxy) -dialkylsilane, 1,8-naphthalimides, a-cyano-β, β-diphenylacrylic acid derivatives, bis (2-benzoxazolyl) alkanes, bis (2) derivatives -naftoxazolyl) alkanes, metonylated malonitriles which contain aryl and heterocyclic substituents, alkylenebis (dithio) carbamate, 4-benzoyl-3-hydroxyphenoxyethyl acrylate, 4-benzoyl-3-hydroxyphenoxyethyl methacrylate, aryl or alkyl substituted acrylonitriles, 3-methyl-5-isopropylphenyl- 6-hydroxycoumarona, 8-acetyl-3-dodecyl-7,7,9,9-tetramethyl-1,3,8-triaza-spiro (4,5) decanol-2,4-dione. Particularly useful ultraviolet light stabilizers that can be used are hindered amines of piperidyl derivatives and nickel compounds such as [l-phenyl-3-methyl-4-decanoylpyrazolate (5)] -Ni, bis [phenyldithiocarbamate] -Ni (II), and others that will be apparent to those familiar with the art. Particularly preferred is the following mixture of ultraviolet light stabilizers 2- [2'-hydroxy-3 ', 5' -1 (1-l-dimethylpropyl) phenyl] benzotriazole and bis- [4- (1, 2, 2 , 6, 6-pentamethylpiperidyl)] 2-butyl-2- [3,5-t-butyl-4-hydroxyphenyl) methyl] Another useful mixture of ultraviolet light stabilizers is 2- (benzotriazole -2 -VL) -4, 6-bis (methylethyl-1-phenylethyl) phenol and 2- (3-hydroxy-3,5'-di-tert-amylphenyl) benzotriazole. Generally, the clear coating composition of this invention is applied by conventional spraying techniques to a base color coating of a car or truck and then baked. Preferably electrostatic spraying is used to apply the composition. The coatings are baked at about 80 ° to 200 ° C for about 10 to 60 minutes. The resulting clear coating is approximately 25-127 μm (1-5 mils) thick, preferably 25-51 μm (1-2 mils) thick and have excellent gloss, good adhesion to the color coating and excellent weather resistance. In the following examples, all parts and percentages are on a weight basis, unless otherwise indicated. The average molecular weight of the polymers is determined by GPC (gel permeation chromatography) using polystyrene as a standard. The resistance to habitual wear and scraping are finally judged by visual perception. In order to provide quantitative comparisons in use, an image analysis method is used to evaluate the standardized surface damage technique. The damage is done using a stoneware suspension, which mimics the damage that occurs by washing a car. This kind of damage is one of the main areas of complaint of termination in the automotive business. The relationship between the result of image analysis and visual perception is non-linear. For example, an image analysis reading of 95% is acceptable, but a coating that has a comparative reading of 72% may look very poor.

EXAMPLE 1 A paint is formulated by mixing together the following constituents: 1. Melamine-methylated / butylated formaldehyde resin, Cymel ^ 1168 from Cytec Industries / 44.26 grams. 2. Melamine resin-methylated / butylated formaldehyde Resimene * RF-4514 from Monsanto Chemicals / 61.82 grams 3. Microgel of the "procedure" that follows / 24.17 grams. 4. Silica dispersion of "procedure" that follows / 51.75 grams. 5. "Procedure" stabilizer package /29.4 grams. 6. Acrylic polymer I of "procedure" that follows / 72.02 grams. 7. Aliphatic oligomer of "procedure" /53.38 grams. 8. Self-stabilized dispersed "process" resin that follows / 98.46 grams. 9. Methanol / 3.68 grams. 10. Butanol / 15.32 grams. 11. Ethylene glycol monobutyl ether acetate / 14.10 grams. 12. Catalyst solution / 9.6 grams. This solution consists of Cycol ^ 600 (sulfonic acid from American Cyanamide) 48%, AMP-95MR (amine from Angus Chemical) 11% and methanol 41%. This coating is dispersed over a base coat supported in black solvent, which has not been previously cured. The coating is cured for 30 minutes at 141 ° C (285 ° F). The coating exhibits comparable hardness and usual wear resistance significantly better compared to any equivalent coating manufactured without the adduct.

Property With Adduct Without adduct Hardness 11.5 knoop 13.2 knoop Resistance to 95.4% 72.7% habitual wear1 PROCEDURES Aliphatic oligomer The following constituents were charged to a reactor equipped with a thermometer, stirrer, nitrogen purge and condenser.

Portion I Parts by weight Proportion in moles Epsilon-caprolactone 597.9 4 ixtThe surface of the panel is scratched in a "rub-rub test" using a 3% suspension of aluminum oxide in water and a felt pad, scratching is carried out using a Daiel rubbing tester. uses 10 cycles with a weight of 500 grams.The classification shown is the percent of the surface which is not scratched, measured by image analysis. 9, 10-dihydro-9-oxa-10-phosphafenanthren-10-oxide 9.4 l, 3,5-tris (2-hydroxyethyl) cyanuric acid 342.2 1 dibutyltin dilaurate 0.2 methyl ethyl ketone 34.2 The ingredients are heated to 125 ° C with mixing; the batch is exothermic at 140 ° C and maintained at 140 ° C for 8 hours. The batch is cooled and filled. The solids constitute 96.5%; the viscosity is 3125 centipoise; The color APHA is .

Microgel A dispersed polymer microgel is prepared by charging the following constituents in a polymerization reactor equipped with a heat source and a reflux condenser.

Portion I Parts by weight Mineral spirits (e.g. 157-210 ° C) 97,614 Heptane 37,039 2,2'-azobis (2-methylbutanonitrile) 1,395 Methacrylate copolymer 4,678 Stabilizing methyl methacrylate monomer 15,187 Portion II Methyl methacrylate monomer 178,952 Styrene monomer 75,302 Hydroxyethyl acrylate monomer 23,455 Mineral spirits (e.g., range 157-210 ° C) 32,387 Heptane 191,896 N, N-dimethylethanolamine 1.108 Glycidyl methacrylate monomer 2,816 Methacrylate copolymer stabilizer 58,271 Methacrylic acid monomer 2,816 Portion III Toluene 12.938 Heptane 30.319 2,2 '-azobis (2-methylbutanonitrile) 2.024 Portion IV Heptane 16.204 Portion V Melamine resin and methylated / butylated formaldehyde 246,300 TOTAL 1067,300 Portion I is charged to the reaction vessel and heated to its reflux temperature. It is refluxed for 60 minutes. Portions II and III are added simultaneously over a period of 180 minutes, while maintaining the resulting reaction mixture at its reflux temperature. The IV portion is then added to the reactor and the reaction mixture is refluxed for 120 minutes. The excess solvents (246.3 parts) are then distilled off and the reactor content is cooled to 101.7 ° C. After cooling, the V portion is added and mixed at 30 minutes while continuing to cool to 60 ° C. The resulting dispersion is 70.0% by weight solids.

Silica dispersion A dispersion consisting of 39.8% n-butyl alcohol, 47.7% Cymel ^ 1133, a methylated / butylated melamine resin purchased from Cytec Industries, and 12.5% amorphous fumed silica, "Aerosil R-972" produced by Degussa Inc Acrylic Polymer I A polymer solution is prepared by charging the following constituents in continuous agitation tank polymerization reactors equipped with heat sources and reflux condensers.

Portion I Parts by weight Hydroxypropyl monomer 232,300 Isobutyl methacrylate monomer 132,800 Styrene monomer 199,100 Butyl acrylate monomer 99,600 Aromatic hydrocarbon (range, e.g. 155-177 ° C) 30,800 Portion II T-Butyl Peroxyacetate 56.440 Aromatic Hydrocarbon (range of pp. 155-177 ° C) 105,400 Portion III Butyl peroxyacetate 4.980 Aromatic hydrocarbon (range of e.g. 155-177 ° C) 9,300 Portion IV T-butyl peroxyacetate 4.980 Aromatic hydrocarbon (range, e.g., 155-177 ° C) 9,300 TOTAL 885,000 The resin is loaded in each reactor of a continuous agitation tank polymerization system up to 10% capacity. The reactors are then heated under pressure to the following specifications: R1 = 190 ° C, 137.8 kPa, R2 = 155 ° C, 103.35 kPa and R3 = 133 ° C, atmospheric pressure. The feeding of each portion and the transfers between the reactors start later. The portion I is fed to R1 at a rate of 6.64 parts / minute, the portion II is fed to R1 at a rate of 1541 parts / minute, the portion III is fed to R2 at a rate of 0.136 parts / minute and portion IV is fed to R3 at a rate of 0.136 parts / minute. The final product is continuously transferred from R3 to a storage tank. The resulting acrylic polyol resin has 80.0 wt% solids.

Stabilizer The stabilizing additive is manufactured in the following manner. 66 parts by weight of xylene are added: 13 parts by weight of Tinuvin ^ 0792, a hindered amine light stabilizer; 7 parts by weight of Tinuvin "11 1130, an ultraviolet filter, 6 parts by weight of Tinuvin ™ 440, a hindered amine light stabilizer, 5 parts by weight of Tinuvin® 900, an ultraviolet filter, where all Tinuvin components "11 are obtained from Ciba Geigy.

Scattered Self-stabilized Resin The following ingredients are added to a 5 liter flask fitted with a stirrer, thermometer, condenser and addition funnels. The mixture is stirred under nitrogen and the temperature is increased to reflux (100 ° C to 104 ° C). The ingredients are provided in parts by weight (to the nearest whole number, for the most part). The dispersed polymer is 63.5% by weight solids in toluene having an average molecular weight weight of 8100. The composition of an acrylic polymer II is as follows: STY / BA / BMA / HEA / MAA / GMA (14.7 / 43.6 / 27.5 / 10.1 / 2.3 / 1.7) dispersed polymer 206 isopropanol 12 spirits 94 heptane 53 butanol 3 It is added as a reflux filler such as t-butyl peroctoate (0.5 parts) and mineral spirits (5 parts). Subsequently the following ingredients are added during a period of 210 minutes, at reflux: styrene 52 hydroxyethyl acrylate 86 methyl methacrylate 126 glycidyl methacrylate 5 methacrylic acid 14 methyl acrylate 62 dispersed polymer 103 These ingredients are added later and the reaction is maintained for 45 minutes: butanol 12 heptane 17 t-butyl peroctoate 5 mineral spirits 31 Subsequently butanol (16 parts) and t-butyl peroctoate (1.7 parts) are added over a period of 30 minutes and then the reaction is maintained for 60 minutes. Finally, the reactor cleans 76 parts of solvent. The particle size is 298 nm as measured by quasi-elastic light scattering and has a viscosity of room temperature of 2000 centipoise at 5 rpm in a Brookfield viscometer and a solids weight of 63.5%. It is noted that in relation to this date, the best method known to the applicant to carry out the aforementioned invention, is the conventional one for the manufacture of the objects or products to which it refers.

Claims (7)

2. Having described the invention as above, the claim is claimed as contained in the following claims: 1. A characterized coating composition comprising an organic liquid carrier and a film-forming binder formed from: (i) an acrylic polymer , I, of monomers that are selected from the group consisting of alkyl methacrylate, alkyl acrylate, hydroxyalkyl styrene acrylate, hydroxyalkyl methacrylate and a combination thereof; the polymer has an average molecular weight weight of about 3,000 to 20,000; (ii) a self-stabilized dispersed resin formed by polymerizing the following constituents: (a) an acrylic polymer, II, of ethylenically unsaturated carboxylic acid, and monomers that are selected from the group consisting of styrene, alkyl methacrylate, alkyl acrylate, acrylate of hydroxyalkyl, hydroxyalkyl methacrylate and a combination thereof; the polymer has an average molecular weight weight of about 3,000 to 20,000; and (b) monomers which are selected from the group consisting of styrene, alkyl methacrylate, alkyl acrylate, hydroxyalkyl acrylate, hydroxyalkyl methacrylate, methacrylic acid, glycidyl methacrylate, glycidyl acrylate and combinations of. the same; wherein the carboxylic group of the acrylic polymer, II, is subsequently reacted with glycidyl methacrylate, or glycidyl acrylate; and (iii) an alkylated melamine and formaldehyde crosslinking agent; wherein the improvement comprises replacing at least 5% by weight of (i) with at least one crosslinkable aliphatic oligomer having an average molecular weight not exceeding 2,500, the aliphatic oligomer is formed of caprolactone and hydroxyethylcyanuric acid, or of the reaction product of a multifunctional alcohol which reacts with monomeric anhydride and which further reacts with monofunctional epoxy. 2. The coating composition according to claim 1, characterized in that the binder comprises: (i) 5-75% by weight, based on the weight of the binder, of the acrylic polymer I substituted by about 5 to 50% of the oligomer crosslinkable aliphatic; (ii) 5-45% by weight based on the weight of the binder, of a self-stabilizing dispersion resin; and (iii) 20-50% by weight, based on the weight of the binder, of the alkylated formaldehyde melamine crosslinking agent.
3. 3. The coating composition according to claim 1, characterized in that it comprises 50-80% by weight of a film-forming binder and 20-50% by weight of an organic solvent for the binder; wherein the binder comprises approximately: (i) 5-75% by weight of a solution of the acrylic polymer I consisting essentially of 5-30% by weight of styrene, 10-40% by weight of butyl methacrylate, 10-40 % by weight of butyl acrylate or hydroxypropyl acrylate and having an average molecular weight weight of about 5,000-15,000; and (ii) 5-45% by weight of a self-stabilizing dispersion resin formed by polymerizing the following constituents in solution: (a) an acrylic solution of polymer II consisting essentially of 5-25% by weight of styrene, 20-40% by weight of butyl acrylate, 20-40% by weight of butyl methacrylate, 5-25% by weight of hydroxyethyl acrylate, 1-5% by weight of acrylic acid, 10-20% by weight of ethyl methacrylate and having an average molecular weight of about 7,000-15,000, (b) monomers of styrene, methyl methacrylate, hydroxyethyl acrylate, methacrylic acid, methyl acrylate and glycidyl methacrylate; wherein the carboxyl groups of the acrylic polymer II are subsequently reacted with glycidyl methacrylate; (iii) 25-40% by weight of a melamine formaldehyde crosslinking agent completely methylated and butylated.
4. 4. The coating composition according to claim 1, characterized in that the oligomer is an adduct of caprolactone and hydroxyethylcyanuric acid.
5. 5. The coating composition according to claim 4, characterized in that the oligomer is formed from a 4: 1 molar ratio of epsilon caprolactone to 1,3,5-tris (2-hydroxyethyl) -cyanuric acid.
6. 6. A substrate, characterized by being coated with a cured layer of the composition according to claim 1.
7. 7. A substrate, characterized in that it is coated with a layer of a pigmented paint composition and a layer of the composition in accordance with Claim 1