MXPA00010724A - Polyacrylics containing pendant acetoacetonate moieties - Google Patents

Abstract

A liquid coating composition curable at ambient temperature comprising a polyacetoacetate-containing component and a polyamine component, the former comprising bulky pendant moieties that contribute to rapid cure and robust films of good early hardness.

Description

POLYACRYLIC PRODUCTS CONTAINING PORTIONS OF PENTATIVE ACETOACETONATE The present invention relates generally to high solids, low VOC coating compositions (organic, volatile components) and more particularly to fast-drying two component compositions suitable for automotive coatings.

BACKGROUND OF THE INVENTION The time necessary before a priming or priming paint can be sanded after priming on a car body surface after application, without fouling the sandpaper, is reaching be increasingly important as it determines how many cars can be repaired per day. It is typical for thermosetting resin systems, different from isocyanate-based, two-pack (2K), traditional polyacrylic products containing pendant acetoacetate groups (AcAc) as a component of the binder resin and an amine and / or a ketimine oligomer and / or a polymer like the other. However, this REF: 123877 approach does not provide a sufficiently rapid formation of solid coatings that can be easily sanded since they must adhere to the viscosity restrictions imposed by the United States Environmental Protection Agency (EPA) (<0.576 kilograms (<4.8 pounds) of organic, volatile (VOC) / liter (gallon) content). Various attempts have been made to produce rapid coating formation. U.S. Patent No. 4,772,680 (hereinafter patent * 680) discloses polymers of average molecular weight in the range of 1000 to 1000,000. However, to comply with the above EPA regulation, the average molecular weight must actually be less than about 45,000, otherwise the coating composition becomes too viscous to be of practical use or has a time for hardening in the container or very short lifespan of less than 30 minutes. One approach to overcome this problem is to use a coating composition containing polymers having high glass transition temperatures (Tgs). However, with the ever increasing restrictions on the allowable amount of VOC that can be released into the atmosphere and the attendant molecular weight limitations, it becomes more difficult to polymerize polymers that have Tg 's above 40 ° C and that they have enough outstanding AcAc groups (for example, 10 to 40% by weight). Such polymers having the desired crosslink density are required to achieve a good durability of the repairs. Therefore, one can not apply the teaching of the x680 patent for polymers with Tg's above about 40 ° C and still comply with EPA restrictions. The present invention provides coating compositions containing high Tg polymers and represents a significant advance over the teachings of the patent? 680 BRIEF DESCRIPTION OF THE INVENTION The present invention is directed to a coating composition comprising: a crosslinking component comprising a polyamine, a polyketimine, or a combination thereof, wherein the polyamine has an average of at least two functionalities per polyamine molecule and wherein the polyketimine has an average of at least two ketimine functionalities per polyketimine molecule; and a binder component comprising: a polyacetoacetate having at least two acetoacetate functionalities, the polyacetoacetate which is polymerized from a monomer mixture comprising a methacrylate monomer, a styrene monomer, or a combination thereof, the methacrylate and styrene monomers each having a sloping, bulky portion, wherein a coating of the coating composition in a two hour cure has a Persoz hardness of approximately greater than or equal to 60 by a dry film thickness greater than or equal to 40 microns. The present invention is also directed to a method for the production of a coating on a substrate, the method comprising: mixing a crosslinking component with a binder component to form a mixture of the container, the crosslinking component comprising a polyamine, a polyketimine or a combination thereof, the polyamine having an average of at least two amine functionalities per polyamine molecule and polyketimine having an average of at least two ketimine functionalities per polyketimine molecule; the binder component comprising a polyacetoacetate having at least two functionalities of acetoacetate, the polyacetoacetate being polymerized from a mixture of monomers comprising a methacrylate monomer, a styrene monomer, or a combination thereof, the methacrylate monomers and of styrene each having a sloping, voluminous portion; apply a layer of the mixture of the container on the surface; and curing the layer under ambient conditions to form the coating on the surface of the substrate, the coating in a two-hour cure has a Persoz hardness of approximately greater than or equal to 60 for a dry film thickness greater than or equal to 40 microns. One of the advantages of the present invention is its low VOC, which is significantly below the current EPA standards. Another advantage of the composition of the present invention is that it is free of the isocyanate groups. As a result, it has less toxicity than conventional polyurethane coatings, prepared from the compounds containing isocyanate groups. This reduced toxicity is particularly useful for automobile paint repair shops that may not have the physical facilities required to handle the most toxic compositions containing isocyanate functionalities. Yet another advantage of the composition of the present invention is that it reduces the time for sanding, before the coating can be sanded without soiling the sandpaper, due to which the number of repairs that could be made in one day is increased. . Yet another advantage of the composition of the present invention is that it does not release pungent odors frequently associated with low molecular weight compounds containing functional acrylate moieties. Compounds such as these are employed in some conventional, low VOC-free, isocyanate-containing coating compositions.

DETAILS OF THE INVENTION As defined herein: "Two-pack coating composition" means a thermosetting composition comprising two components that are stored in separate containers, which are typically sealed to increase the life of the components. of the coating composition. The components are mixed just before use to form a mixture of the container, which has a limited shelf life, typically a few minutes, such as 15 minutes to 45 minutes to a few hours, such as 2 hours to 6 hours. The mixture of the container is applied as a layer of desired thickness on a surface of the substrate, such as a car body. After application, the layer is dried and cured to form a coating on the surface of the substrate having the desired coating properties, such as solvent resistance. "A low VOC coating composition" means a coating composition that is less than about 0.6 grams of organic solvent per liter (4.8 pounds per gallon) of the composition, determined under the procedure provided in ASTM D3960. "High solids composition" means a coating composition having a solids component of "above 20 percent, preferably in the range of 25 to 95 percent and more preferably in the range of 30 to 80 percent, all in percentages by weight based on the total weight of the composition.

"Weight average molecular weight by GPC" means a weight average molecular weight measured by using gel permeation chromatography. High performance liquid chromatography (HPLC) supplied by Hewlett-Packard, Palo Alto, California was used. Unless stated otherwise, the liquid phase used was tetrahydrofuran and the standard was polymethyl methacrylate. "Polydispersity" means the weight average molecular weight by the GPC divided by the number average molecular weight by the GPC. "Polymeric solids" or "binding solids" means a polymer or binder in its dry state. "A sloping, bulky portion" means a group in a polymer that restricts the segmented movement of the polymer backbone. The present invention is directed to a coating composition suitable for various coating processes, particularly in the processes of giving a new surface to a car used for the coating of automobile bodies. The composition is a two pack composition, which includes a crosslinking component and a binder component.

Typically, a cure time of about 3 hours is required for the conventional polyacetoacetate-ketimine binder systems before they can be sanded without soiling the sandpaper. However, there is a need for a coating composition that provides a coating that can be sanded in 1 hour or less without adversely affecting firmness [ie, image clarity (DOI) and firmness). Bevel edge or chamfer (F / E) once the last coat is given with a base coat and clear coat, or with an individual stage coating. One approach to achieve this goal is to increase the transition temperature of the vitreous state (Tg) of the polyacetoacetate. However, the amount of the monomer containing the crosslinkable portion, for example, a AcAc functionalized monomer, should be maintained in the range of about 10 to 80 weight percent to provide sufficient crosslinking so that the firmness is not adversely affected. . The range of weight percentage above is important to avoid the behavior of lacquer-type priming paint with little or no cross-linking in which the firmness of DOI and F / E are poor due to the increase in volume of the solvent after the application of the last coat of paint. further, the molecular weight for conventional spraying will be in the range of approximately 5,000 to 50,000, or the viscosity will be too high to be used in a primer-surfacer paint formulation that adheres to the current restrictions of the Environmental Protection Agency (EPA) (that is, 0.576 (4.8) of VOC or less). An unexpected discovery has been made that allows the use of a polymerized polyacetoacetate from a sufficient amount of the crosslinkable monomer (e.g., 10 to 80% monomer functionalized with AcAc) to provide good firmness of DOI and F / E, having a reasonable molecular weight (5,000 to 50,000) so that it can be easily applied by a conventional spray gun, and having a sufficiently high Tg (eg, 40 ° to 150 ° C) to provide a two pack coating composition, Quick drying that produces a coating that is well sanded (ie no fouling of the sandpaper occurs) in a short cure time of about one hour. It was discovered that the above results could be realized by incorporating bulky monomers with a high Tg (rigid) in the polyacetoacetate used in the coating composition of the present invention to provide the resulting polyacetoacetate with bulky pendant portions. The coating from the coating composition of the present invention has a Persoz hardness of approximately more than or equal to 60, preferably in the range of 60 to 150, more preferably in the range of 70 to 120 for a dry film thickness greater than or equal to 40 microns. The coating composition includes in the range of about 10 percent to 90 percent, preferably in the range of 10 percent to 70 percent and more preferably in the range of 15 percent to 60 percent of the component of crosslinking, the percentages that are in percentages by weight based on the total weight of the solids of the binding and crosslinking components. The crosslinking component includes a polyamine, a polyketimine or a combination thereof. Polyketimine is preferred. When used as a combination of a polyamine and a polyketimine, the ratio thereof in parts by weight is in the range of 1 to 100 to 100 to 1, preferably in the range of 1 to 50 to 50 to 1, more preferably in the range of 1 to 20 to 20 to 1. The polyamine has a weight average molecular weight of at least 100, determined by gel permeation chromatography using polymethyl methacrylate standards. Typically, the weight average molecular weight by the GPC ranges from about 100 to about 100,000, preferably from about 200 to about 50,000 and more preferably from about 300 to about 10,000. The polyamine has an average of at least two amine functionalities per molecule, which may be primary, secondary or a combination of secondary and primary amine functionalities. Preferably, the polyamine has an average of about 2 to about 25 and more preferably, in the range of about 2 to 'about 6 amine functionalities per polyamine molecule and has 2 to 200, preferably 6 to 100 and more preferably 8 to 50 carbon atoms. These amine functionalities may be present either as pending functionalities or amine functionalities placed in the main chain of the polymer chain. The pending amine functionalities are preferred. Examples of the representative polyamines for use in the invention include aliphatic or cycloaliphatic amines, or a combination thereof. The aliphatic polyamine is preferred. Examples of suitable polyamines include primary and secondary amines, such as ethylene diamine, propylene diamine, butylene diamine, pentamethylenediamine, hexamethylenediamine, decamethylenediamine, 4,7-dioxadecane-1, 10-diamine, dodecamethylenediamine, 4,9-dioxadodecan-1, 12-diamine, 7-methyl-4, 10-dioxatridecan-1, 13-diamine, 1,2-diaminocyclohexane, 1, -diaminocyclohexane, 4,4'-diminodicyclohexyl methane, isophorone diamine, bis (3-methyl-4-) aminocyclohexyl) methane, 2,2-bis (4-aminociclohexyl) propane, nitrile tris (ethanolamine), bis (3-aminopropyl) methylamine, 3-amino-1- (methylamino) propane, 3-amino-1- (cyclohexylamino) ) propane and N- (2-hydroxyethyl) ethylene diamine. Ethylene diamine, propylene diamine, butylene diamine and 1,2 diaminocyclohexane are preferred. Other suitable polyamines include those of the formula: H2N - (R2) n -NH - (R?) N - NH2, where the groups Rx and R2 may be the same 0 and represent an alkylene group containing 2 to 6 and preferably 2 to 4 carbon atoms and n is an independently selected number in the range of 1 to 6 and preferably in the range of 1 to 3. The alkylene group is a cycloalkylene group or an alkylene group containing an ether-oxygen atom. Examples of representative polyamides containing polyalkylene groups include diethylene triamine, dipropylene triamine and dibutylene triamine. It is preferred that these polyamines should be of a cycloaliphatic nature and contain 5 to 15 carbon atoms, such as isophoronediamine; more particularly containing an alpha-alkyl group, such as bis (3. {methyl-4-aminocyclohexyl) methane and bis (3-methyl-4-aminocyclohexyl) propane. Other suitable polyamines include the reaction products of primary or secondary polyamines, such as ethylene diamine, diethylene triamine and isophorone diamine, with polyfunctional epoxy, isocyanate, maleinate, fumarate, acryloyl, methacryloyl or a combination thereof. Some of the suitable polyepoxides include those which contain at least two oxirane groups in the molecule, i.e. where n is at least two, Rx is hydrogen or methyl, and R2 represents broadly an organic base molecule or a polymer typically composed of carbon, hydrogen, oxygen and optionally nitrogen, sulfur, or both. Hydroxyl substituents may also be present, as well as halogen and ether groups. In general, the epoxide equivalent weight ranges from about 100 to about 1500, preferably from about 100 to about 1200, and more preferably from about 150 to about 600. These polyepoxides can be broadly categorized as being aliphatic, aromatic , cyclic, acyclic, alicyclic or heterocyclic. Another group of polyepoxides useful for use in the present invention include epoxy novolac resins. These resins are prepared by reacting an epihalohydrin with the condensation product of an aldehyde with a monohydric or polyhydric phenol. An example is the reaction product of epichlorohydrin with a condensate product of phenol formaldehyde. Another particularly preferred group of the polyepoxides are the polyglycidyl ethers of hydroxy, aromatic, polyhydric compounds, such as, for example, dihydric phenols. The phenol must be at least dihydric, such as, for example, resprcinol, catechol, hydroquinone, bis (4-hydroxyphenyl) -1, 1-isobutane; 4, 4-dihydroxybenzophenone; bis (4-hydroxyphenyl) -1,1-isobutane; 4, 4-dihydroxybenzophenone; bis (4-hydroxyphenyl) -1, 1-ethane; bis (2-hydroxy-phenyl) methane; 1, 5-hydroxynaphthalene and 4,4'-isopropylidenediphenol, that is, bisphenol A. Bisphenol A is preferably used. Of many possible polyepoxides, epichlorohydrin is mainly used, although epibromohydrin is also very useful. The polyglycidyl ethers especially useful herein are obtained by reacting epichlorohydrin and bisphenol A in the presence of an alkali, such as sodium or potassium hydroxide. The series of epoxy resins sold by Shell Chemical Company under the trademark EPON are especially useful herein. Another group of useful polyepoxides are the polyglycidyl ethers derived from the reaction of epihalohydrin, preferably epichlorohydrin, with polyhydric alcohols, such as ethylene glycol; diethylene glycol; triethylene glycol; 1,2-propylene glycol; 1,4-butylene glycol; 1,5-pentanediol; 1, 2, 6-hexanotriol; glycerol and trimethylolpropane. Also useful are polyepoxides which are polyglycidyl ethers of polycarboxylic acids. These materials are produced by the reaction of an epoxy compound, such as epichlorohydrin with an aliphatic or aromatic polycarboxylic acid such as oxalic acid; succinic acid; glutaric acid; terephthalic acid; 2,6-naphthalene dicarboxylic acid and dimerized linoleic acid. Still another group of polyepoxides are derived from the epoxidation of the alicyclic, olefinically unsaturated materials. Among these are the epoxy alicyclic ethers and esters, which are well known in the art. It should be understood that mixtures of polyepoxides are also useful herein. The preferred epoxy equivalent weight of the pliepoxide (s) is in the range of about 87 to 6000, more particularly the range of 120 to 1000. Suitable polyoxides include those containing the oxyalkylene groups, i.e. wherein R is hydrogen or alkoyl of 1 to 6 carbon atoms, m is an integer ranging from 1 to 4 and n is an integer ranging from 2. to 50. The proportion of the oxyalkylene groups in the polyepoxide depends on a number of factors, among them the size of the oxyalkylene group and the nature of the polyepoxide. Examples of suitable polyisocyanates include di-, tri or aliphatic, cycloaliphatic or aromatic tetraisocyanates which may or may not be ethylenically unsaturated, such as 1,2-propylene diisocyanate, trimethylene diisocyanate, tetramethylene diisocyanate, diisocyanate 2 , 3-butylene, hexamethylene diisocyanate, octamethylene diisocyanate, 2,2,4-trimethyl hexamethylene diisocyanate, 2,4,4-trimethyl hexamethylene diisocyanate, dodecamethylene diisocyanate, omega, omega-dipropyl ether diisocyanate, diisocyanate 1, 3-cyclopentane, 1,2-cyclohexane diisocyanate, 1,4-cyclohexane diisocyanate, isophorone diisocyanate, 4-methyl-1,3-diisocyanatocyclohexane, trans-vinylidene diisocyanate, dicyclohexylmethane-4,4'-diisocyanate , 3,3'-dimethyl-dicyclohexylmethane-4,4'-diisocyanate, a toluene diisocyanate, 1,3-bis (1-isocyanatol-methylethyl) benzene, 1,4-bis (1-isocyanato-1-methylethyl) benzene, 1, 3-bi (isocianatome useful) benzene a xylene diisocyanate, 1,5-dimethyl-2, -bis (isocyanatomethyl) benzene, 1,5-dimethyl-2, -bis (2-isocyanatoethyl) benzene, 1, 3,5-triethyl-2, 4-bis (isocyanatomethyl) benzene, 4,4'-diisocyanatodiphenyl, 3,3'-dichloro-4,4'-diisocyanatodiphenyl, 3,3 '-diphenyl-4,4'-diisocyanatodiphenyl, 3,3'-dimethoxy- 4,4'-diisocyanatodiphenyl, 4,4'-diisocyanatodiphenylmethane, 3,3'-dimethyl-4,4'-diisocyanatodiphenyl methane, a diiocyanatophthalene, polyisocyanates having isocyanurate structural units, the adduct of 2 molecules of a diisocyanate, as hexamethylene diisocyanate or isophorone diisocyanate and a diol such as ethylene glycol, the adduct of 3 molecules of hexamethylene diisocyanate and 1 water molecule (available under the trademark Desmodur® N from Bayer Corporation of Pittsburgh, Pennsylvania), the adduct of 1 molecule of trimethylol propane and 3 molecules of toluene diisocyanate (available under the trademark Desmodur® L from Baye r Corporation), the adduct of 1 molecule of trimethylol propane and 3 molecules of isophorone diisocyanate, the compounds such as 1, 3, 5-triisocyanatobenzene and 2, 4, 6-triisocyanatotoluene, and the adduct of 1 molecule of pentaerythritol and toluene diisocyanate molecules. Examples of suitable polyacrylates or polymethacrylates include polymerized monomers, such as acrylic or methacrylic esters of a mono, di or polyfunctional hydroxyl compound including methyl acrylate, methyl methacrylate, ethyl acrylate, hydroxyethyl acrylate, hydroxyethyl methacrylate, acrylate. of propyl, hydroxypropyl methacrylate, butyl acrylate, butyl methacrylate, hydroxyhexyl acrylate, 2-ethylhexyl acrylate, octyl acrylate, isobornyl acrylate, oleyl acrylate, glycidyl methacrylate or (meth) acryloxypropyl trimethoxysilane. The polyketimines, which are suitable for use in the present invention, are obtained by blocking the amino groups in the polyamines described above with a blocking agent, such as a ketone having not more than 18 carbon atoms, preferably 3 to 10 carbon atoms. The polyketimine suitable for use in the coating composition of the present invention has a weight-average molecular weight in the range of 100 to 100,000. The polyamine is preferably blocked with a ketone represented by the following formula: I R-C-R ' wherein R and R 'are independently selected from alkyl groups having 1 to 12, preferably 1 to 8, carbon atoms. An aliphatic or cycloaliphatic ketone is preferred and an aliphatic or cycloaliphatic ketone with 3 to 8 carbon atoms is more preferred. The polyamine suitable for use in the coating composition of the present invention includes: I. an adduct of a diglycidyl ether amine based on bis (4-hydroxyphenyl) -2,2-propane; II. an adduct of an amine and dimethyl maleate; or III. an adduct of an amine prepared from a polyacrylate having at least two acrylate groups per molecular and having a molecular weight by weight of about 100 to 50,000.

Examples of suitable blocking agents for the amino groups include acetone, diethyl ketone, methyl isobutyl ketone, isobutyraldehyde, hydroxybutyraldehyde, pentanone, cyclohexanone, ethylamyl ketone, hydroxy citronella, isophorone and decanone. The binder component of the coating composition includes in the range of the percent from 1 percent to 90 percent, preferably in the range of 5 percent to 80 percent and more preferably in the range of 20 percent to 60 percent of at least one polyacetoacetate, the percentages that are in percentages by weight are based on the total weight of the binder solids. The polyacetoacetate has at least 2, preferably in the range of 2 to 30, more preferably in the range of 2 to 25 and even more preferably in the range of 2 to 10 and more preferably in the range of acetoacetate groups. The polyacetoacetate has a weight average molecular weight by GPC in the range of 100 to 50,000, preferably in the range of 200 to 40,000 and more preferably in the range of 1,000 to 35,000. The polyacetoacetate has an acetoacetate equivalent weight (grams / equivalent) of from about 100 to about 1500, preferably from about 100 to about 1000 and more preferably from about 200 to about 950. The polyacetoacetate has a Tg in the range of 40 ° C to 150 ° C, preferably in the range of 50 ° C to 100 ° C and more preferably in the range of 55 ° C to 90 ° C. The ratio of equivalents of the amine in polyamine or polyketimine to polyacetoacetate is in the range of 0.3 to 2.5, preferably in the range of 0.5 to 2.0 and more preferably in the range of 0.6 to 1.8. The polyacetoacetate is polymerized from a mixture of monomers which includes in the range of 5 percent to 90 percent, preferably in the range of 10 percent to 70 percent, and most preferably in the range of 15. percent to 60 percent of a monomer functionalized with acetate acetate. All percentages that are by weight are based on the total weight of the solids of the binder component. The monomer mixture described above also contains in the range of 5 percent to 90 percent, preferably in the range of 10 percent to 70 percent, and more preferably in the range of 15 percent to 60 percent. one hundred of a methacrylate monomer, a styrene monomer, or a combination thereof, each provided with a sloping, bulky portion. Examples of suitable methacrylate monomers having the pendant, bulky portion include isobornyl methacrylate, cyclohexyl methacrylate, t-butylcyclohexyl methacrylate, trimethylcyclohexyl methacrylate, t-butyl methacrylate or a combination thereof. Examples of suitable styrene monomers having the pendant, bulky portion include t-butyl styrene, more particularly tertiary butyl styrene supplied by Deltech Corporation, Baton Rouge Louisiana. The monomer mixture described above can include 5 percent to 90 percent, preferably in the range of 10 percent to 70 percent and most preferably in the range of 15 percent to 60 percent of an acetoacetic ester of a hydroxyalkyl (meth) acrylate or an allyl alcohol monomer unit, all percentages which are in percentages by weight are based on the total weight of the monomer mixture. If desired, the monomer mixture can contain 0.1 percent to 90 percent, preferably in the range of 5 percent to 80 percent and more preferably in the range of 10 percent to 70 percent of a acrylic or methacrylic ester of a mono-, di- or polyfunctional hydroxyl compound having 1 to 18, preferably 2 to 10 carbon atoms, all percentages which are in percentages by weight are based on the total weight of the mixture of monomers. Some of the examples of acrylic or methacrylic esters include methyl acrylate, methyl methacrylate, ethyl acrylate, hydroxyethyl acrylate, hydroxyethyl methacrylate, propyl acrylate, hydroxypropyl methacrylate, butyl acrylate, butyl methacrylate, hydroxyhexyl acrylate, 2-ethylhexyl acrylate, octyl acrylate, isobornyl acrylate , oleyl acrylate, glycidyl methacrylate and (meth) acryloxypropyl trimethoxysilane. If desired, the monomer mixture may additionally contain 0.1 percent to 20 percent, preferably in the range of 1 percent to 15 percent and more preferably in the range of 1 percent to 12 percent of a mono or dicarboxylic acid, monoethylenically unsaturated acid having 3 to 12, preferably 3 to 10 carbon atoms or an anhydride thereof, all percentages which are in percentages by weight are based on the total weight of the monomer mixture. Some examples of such acids or anhydrides thereof include acrylic acid, methacrylic acid, maleic acid, itaconic acid, maleic anhydride, cinnamic acid or dodecenic acid. Acrylic acid and maleic anhydride are preferred. If desired, the monomer mixture may contain 0.1 percent to 90 percent by weight of one or more other copolymerizable monomers, such as styrene, -methyl styrene, vinyl toluene, acrylamide, methacrylamide, acrylonitrile, vinyl acetate, versatate of vinyl, trimethoxy silane vinyl and / or allyl glycidyl ether. These monomer units are obtained, for example, by the acetoacetylation of an adduct of a lactone, a monoepoxy compound or a diisocyanate reacted with a diol to a hydroxyalkyl (meth) acrylate. Examples of other suitable monomer units include allyl acetacetate and acetoacetic esters of ethylenically unsaturated diols or triols such as 2-butene-1,4-diacetoacetate of (2-methylene acetoacetyl) -l-propen-3-acetoacetate. The polyacetoacetate can be prepared in any convenient manner, for example by polymerizing one or more monomers containing acetoacetate groups, optionally mixed with one or more of the monomers described above, at a temperature of 50 ° to 160 ° C, in the presence of 0.1-10% by weight of an initiator, calculated on the total amount of the monomer mixture. Examples of suitable initiators include free radical initiators, for example potassium persulfate, hydrogen peroxide, eumeno hydroperoxide, benzoyl peroxide, diter-butyl peroxide, tert-butylpertrimethyl hexanoate, tert-butyl perbenzoate, azobisisobutyronitrile, azobisvaleronitrile , azobis (2,4-dimethylvaleronitrile). The polymerization is carried out in the presence of water and / or an organic solvent, such as ketone, an alcohol, an ether, an ester or a hydrocarbon. The polymerization may optionally be carried out using UV light and in the presence of UV light initiators such as benzyl, benz.oin ethers and thioxanthone derivatives. Other suitable polyacetoacetates are addition polymers having, for example, hydroxyl groups, a number of which have been converted with a reactive acetoacetate compound or a compound producing an acetoacetate group, for example with diketene. Examples of suitable reactive acetoacetate compounds include alkyl esters of acetylacetic acid, preferably methyl acetoacetate or ethyl acetoacetate. Suitable addition polymers containing hydroxyl groups include copolymers of a hydroxyalkyl (meth) acetylate such as hydroxyethyl methacrylate, hydroxypropyl methacrylate and / or hydroxybutyl acrylate and optionally one or more other comonomers and copolymers of styrene and allyl alcohol . If desired, the binder component and the crosslinking component of the coating composition may contain at least one organic solvent. Suitable examples include water, aromatic hydrocarbons, such as naphtha or petroleum xylenes.; Aliphatic hydrocarbons; ketones, such as methyl amyl ketone, methyl isobutyl ketone, methyl ethyl ketone or acetone; diketo compounds, such as an acetyl ketone; nitroalkanes, such as nitropropane; esters, such as butyl acetate or hexyl acetate; esters of glycol ether, such as propylene glycol monomethyl ether acetate; and (cyclo) aliphatic or aromatic acetylacetic acid esters, of which the (cyclo) alkyl group or the aromatic group has 1 to 20 carbon atoms, such as ethylacetoacetate, cyclohexylacetoacetate and phenylacetoacetate. The amount of organic solvent added depends on the desired solids level as well as the desired amount of VOC of the composition. If desired, the organic solvent can be added to both components of the binder. The amount of the organic solvent used in the present invention results in the composition having a VOC of less than 0.576 kilograms (4.8 pounds per gallon) and preferably in the range of 0.012 kilograms to 0.576 kilograms (0.1 pounds to 4.8 pounds per gallon), more preferably in the range of 0.12 kilograms to 0.42 kilograms (0.1 to 3.5 pounds per gallon) and more preferably in the range of 0.012 kilograms to 0.252 kilograms (0.1 to 2.1 pounds per gallon) of organic solvent per liter of the composition. The solids level of the coating of the present invention varies in the range of 5 percent to 100 percent, preferably in the range of 10 percent to 95 percent and more preferably in the range of 25 percent to 85 percent, all percentages are based on the total weight of the coating composition. The coating composition typically contains conventional additives, such as pigments, stabilizers, rheology control agents, flow agents, curing agents, leveling agents, emulsifiers, antifoaming agents, reducing agents, antioxidants, UV light stabilizers settlement control and catalysts such as carboxylic, organic and filler acids. Naturally, these additional additives will depend on the proposed use of the coating composition. Fillers, pigments and other additives that would adversely affect the clarity of the cured coating will not be included if the composition is intended to be used as a clear coating. The above additives may be added to either a binder or crosslinking component, or both, depending on the proposed use of the coating composition. Optionally, the composition may also contain a compound, such as an acrylate (co) polymer, cellulose acetopropionate, cellulose acetobutyrate, nitroceulose, a vinyl polymer, an epoxy resin and / or a compound containing a group, ß- ethylenically unsaturated. The coating composition can be applied to the substrate in any suitable manner, such as by roll coating, spraying, brushing, spreading, spray painting or dip painting. It is preferred that the composition be applied by spraying or roller coating.

In use, the binding and crosslinking components of the coating composition are mixed just before use or approximately 5 to 30 minutes before use to form a mixture of the container, which has limited shelf life, in the range of 10 minutes to 60 minutes, before it becomes too viscous to allow application through conventional application systems, such as spray. A layer of the container mixture is typically applied to a substrate by conventional techniques, such as spray, electrostatic spray, roller coating, dip coating or brush painting. The layer of the coating composition is then cured under ambient conditions in the range of 10 minutes to 3 hours, preferably in the range of 30 minutes to 60 minutes to form a coating on the substrate having the desired coating properties. It is understood that the actual cure time depends on the thickness of the applied layer and on the presence or absence of any suitable drying device, such as fans that aid in the continuous flow of air over the coated substrate to accelerate the rate of cure. In general, a layer having a thickness in the range of 25 microns to 300 microns applied on a metal substrate, such as a car body, is cured in 30 to 60 minutes under ambient conditions and in the absence of any device dryer, adequate. If desired, drying in a furnace of the coated substrate at a temperature of about 60 ° C to 120 ° C for about 10 minutes to 40 minutes may further accelerate the cure rate. The drying step in a previous oven is particularly useful under OEM (Original Equipment Manufacturing) conditions. Suitable substrates include those of pretreated or non-pretreated metals, wood, synthetic materials, paper or leather. Suitable metals include iron, steel and aluminum.

Test Procedures Measurement of sanding To correlate sanding behavior of one hour priming-tack paint without fouling sandpaper, hardness of priming-tack paint and sanding behavior were compared to hardness measurements of Persoz (number of pendular oscillations before the machine stops counting) by using only the crosslinking and binder components of the coating composition. The hardness of the coating was measured with respect to time, by using a Persoz Hardness Test (Under ASTM D4366 Test) when using a Persoz Hardness Analyzer Model No. 5854 supplied by Byk-Millinckrodt, Wallingford, Conicut. It was determined that to obtain good sanding within 1 hour in the body shop, the Persoz instrument had to provide values of approximately > 70 oscillations, 2 hours after deposition of the layer on the steel panels by means of a scraper blade, where the thickness of the dry film, resulting was greater than or equal to 40 microns. The comparative coatings 1 to 4 were prepared by reacting the polyketimines 3 and 6, shown below, with the Comparative Polyacetoacetate (described below) and the coatings 1 to 4 were prepared by reacting the polyketimines 3 and 6, shown below, with the polyacetoacetate of the present invention (described later). The hardness values of Persoz were then determined in 2 hours and are present in Tables 1 and 2, below.

Policetimines Comparative Polyacetoacetate To a reactor, 25.04 parts of xylene were charged and heated to boiling (approximately 140 ° C) under a nitrogen atmosphere. Subsequently, a mixture of 14.91 parts of styrene, 7.46 parts of methyl methacrylate, 10.93 parts of acetoacetoxyethyl methacrylate were concurrently added., 12.42 parts of n-butyl acrylate, 3.98 parts of hydroxyethyl acrylate, and 12.9 parts of xylene for a period of 120 minutes with a mixture of 0.620 parts of t-butylperoxy acetate (75% in mineral spirits), 0.001 parts of t-butyl peroctoate, and 8,039 parts of xylene added during 270 minutes. The reaction mixture was held for a further 60 minutes at boiling after the feeds were completed. After the maintained period, 3.7 parts of xylene were added and the mixture was cooled. The resulting polymer solution had a Gardner-Holt = O viscosity; Solids = 50% in xylenes; Tg = 25 ° C and; p.m. = 25, 000.

Polyacetoacetate of the present invention To a reactor, 24.34 parts of butyl acetate were charged and heated to boiling (about 125 ° C) under a nitrogen atmosphere.

Subsequently, a mixture of 23.87 parts of methyl methacrylate, 17.90 parts of isobornyl methacrylate, 4.77 parts of hydroxyethyl acrylate, 13.13 parts of acetoacetoxyethylmetharylate, and 3.3 parts of butyl acetate was added over a period of 180 minutes. At the same time, 83% of a mixture of t-butylperoxy acetate (75% in mineral spirits) and 7.52 parts of butyl acetate were added during 240 minutes. The reaction mixture was held for a further 60 minutes at boiling after the feeds were completed. After it was maintained, the remaining 17% of the mixture of t-butylperoxy acetate / butyl acetate was added over a period of 30 minutes. The reaction mixture was held for an additional 30 minutes at boiling after the feed was complete. After the maintenance period, 3.52 parts of butyl acetate were added and the mixture was cooled. The resulting polymer solution had a viscosity of Gardner-Holt = S; Solids = 50% in butyl acetate; Tg = 70 ° C; P.m. = 25,000. The composition contains 30% IBOMA and 20% AAEM by weight.

Comparative Coating 1 A mixture of the container was prepared by successively mixing 44.4 parts of the Comparative Polyacetoacetate, 4.95 parts of diisimine of isophorone diamine and methyl isobutyl ketone (MIBK) (biscetimine 3), 16.3 parts of butyl acetate and 2.3 parts of methyl isobutyl ketone. A layer of the resulting container mixture was applied to the surface of a cold-rolled steel panel by means of a scraper blade to give a coating thickness of approximately 40 μm after curing.

Comparative Coating 2 A mixture of the container was prepared by successively mixing 44.4 parts of the Comparative Polyacetoacetate, 10.6 parts of triscetimine prepared from 1 mole of dimethylmaleate, 3 moles of isophorone diamine and 3 moles of MIBK (triscetimine 4, applied as 78% solids in MIBK) and 21 parts of butyl acetate. A layer of the resulting container mixture was applied to the surface of a cold-rolled steel panel by means of a scraper blade to give a coating thickness of approximately 40 μm after curing.

Comparative Coating 3 A mixture of the container was prepared by successively mixing 44.4 parts of the Comparative Polyacetoacetate, 12.8 parts of triscetimine prepared by 1 mole of diglycidyl ether of Bisphenol A and 2 moles of diethylene triamine biscetimine (tetracetimine 5; % solids), 13.6 parts of butyl acetate and 2.3 parts of MIBK. A layer of the resulting container mixture was applied to the surface of a cold-rolled steel panel by means of a scraper blade to give a coating thickness of approximately 40 μm after curing.

Comparative Coating 4 A mixture of the container was prepared by successively mixing 44.4 parts of the Comparative Polyacetoacetate, 8 parts of tetracetimine prepared from 1 mole of 1,6-hexanediol diacrylate and 2 moles of the diethylene triamine biscetimine (tetraacetymine 6, 70% solids). in MIBK) and 17 parts of butyl acetate. A layer of the resulting container mixture was applied to the surface of a cold-rolled steel panel by means of a scraper blade to give a coating thickness of approximately 40 μm after curing.

Coating 1 of the present invention A mixture of the container was prepared by successively mixing 44.4 parts of the Polyacetoacetate of the present invention, 4.81 parts of dicetimine of isophorone diamine and methyl isobutyl ketone (MIBK). (biscetimine 3), 14.5 parts of xylene and 2.3 parts of methyl isobutyl ketone. A layer of the resulting container mixture was applied to the surface of a cold-rolled steel panel by means of a scraper blade to give a coating thickness of approximately 40 μm after curing.

Coating 2 of the present invention A mixture of the container was prepared by successively mixing 44.4 parts of the Polyacetoacetate of the present invention, 10.3 parts of triscetimine prepared from 1 mole of dimethylmaleate, 3 moles of isophorone diamine and 3 moles of MIBK (triscetimine 4; as 78% solids in MIBK) and 19.1 parts xylene. A layer of the resulting container mixture was applied to the surface of a cold-rolled steel panel by means of a scraper blade to give a coating thickness of approximately 40 μm after curing.

Coating 3 of the present invention A mixture of the container was prepared by successively mixing 44.4 parts of the Polyacetoacetate of the present invention, 12.5 parts of tetracetimine prepared from 1 mole of diglycidyl ether of Bisphenol A and 2 moles of the biscetimine of diethylene triamine (tetracetimine 5). applied as a solution of 55% solids), 12 parts of xylene and 2.3 parts of MIBK. A layer of the resulting container mixture was applied to the surface of a cold-rolled steel panel by means of a scraper blade to give a coating thickness of approximately 40 μm after curing.

Coating 4 of the present invention A mixture of the container was prepared by successively mixing 44.4 parts of the Polyacetoacetate of the present invention, 7.8 parts of tetracetimine prepared from 1 mole of a 1,6-hexanediol diacrylate and 2 moles of diethylene triamine biscetimine (tetracetimine, 6; 70% solids in MIBK) and 15.2 parts xylene. A layer of the resulting container mixture was applied to the surface of a cold-rolled steel panel by means of a scraper blade to give a coating thickness of approximately 40 μm after curing.

/ TABLE 1 PoIyAcAc 1 (Comparative Polyacetoacetate Tg = 25 ° C; Pm = 25,000) TABLE 2 PoIyAcAc 2 (Polyacetoacetate of the present invention-Tg = 70 ° C; Pm = 25,000) In all cases, the PoIyAcAc 2 provides Persoz values higher than 1. In addition, the values for the PoIyAcAc 2 show only a small dependence on the amount of the ketimine functionality which indicates the importance of the Tg of the polyacetoacetate on the hardness and the sanding of the resulting coating surface.

It is noted that in relation to this date, the best method known to the applicant to carry out the aforementioned invention, is that which is clear from the present description of the invention.

Having described the invention as above, the content of the following claims is claimed as property.

Claims (18)

1. A coating composition, characterized in that it comprises: a crosslinking component comprising a polyketimine having an average of at least two ketimine functionalities per polyketimine molecule; and a binder component comprising: a polyacetoacetate with a Tg in the range of 40 ° C to 150 ° C and having at least two functionalities of acetoacetate, the polyacetoacetate which is polymerized from a mixture of monomers comprising a methacrylate monomer, a styrene monomer, or a combination thereof, the monomers of methacrylate and styrene each having a sloping, bulky portion, wherein a coating of the coating composition in a two hour cure has a Persoz hardness of approximately more than or equal to 60 for a dry film thickness of more than that or equal to 40 microns.

2. A coating composition, characterized in that it comprises: a crosslinking component comprising a polyamine, a polyketimine, or a combination thereof, wherein the polyamine has an average of at least two amine functionalities per polyamine molecule and wherein the polyketimine has an average of at least two ketimine functionalities per polyketimine molecule; and a binder component comprising: a polyacetoacetate with a Tg in the range of 55 ° C to 150 ° C and having at least two acetoacetate functionalities, the polyacetoacetate which is polymerized from a monomer mixture comprising a monomer of methacrylate, a styrene monomer, or a combination thereof, the methacrylate and styrene monomers each have a sloping, bulky portion, wherein a coating of the coating composition in a two-hour cure has a Persoz hardness of approximately greater than or equal to 60 for a dry film thickness of more than or equal to 40 microns.

3. The coating composition of claim 1 or 2, characterized in that the monomer mixture comprises in the range of 5 weight percent to 90 weight percent of the methacrylate monomer, the styrene monomer, or the combination thereof, all percentages are based on the total weight binder component.

4. The coating composition according to claim 1 or 2, characterized in that the monomer mixture comprises in the range of 10 weight percent to 90 weight percent of the methacrylate monomer, the styrene monomer, or a combination thereof. same, all percentages are based on the total weight binder component.

5. The coating composition according to claim 1 or 2, characterized in that the polyacetoacetate has a weight-average molecular weight in the range of 100 to 50,000.

6. The coating composition according to claim 1 or 2, characterized in that the monomer mixture comprises in the range of 5 weight percent to 90 weight percent of an acetoacetate functionalized monomer based on the total weight of the binder component.

7. The coating composition according to claim 1 or 2, characterized in that the monomer mixture comprises in the range of 10 weight percent to 90 weight percent of an acetoacetate functionalized monomer based on the total weight of the binder component.

8. The coating composition according to claim 1 or 2, characterized in that the methacrylate monomer having the sloping, bulky portion is selected from the group consisting of isobornyl methacrylate, cyclohexyl methacrylate, t-butylcyclohexyl methacrylate, trimethylcyclohexyl methacrylate. , t-butyl methacrylate, and a combination thereof.

9. The coating composition according to claim 1 or 2, characterized in that the styrene monomer having the sloping, bulky portion is t-butyl styrene.

10. The coating composition according to claim 1 or 2, characterized in that the polyamine has a weight average molecular weight in the range of 100 to 100,000.

11. The coating composition according to claim 1, 2 or 10, characterized in that the polyamine is blocked with a ketone represented by the following formula: O R-C-R ' wherein R R 'are independently selected alkyl groups having between 1 and 12 carbon atoms.

12. The coating composition according to claim 1, 2, 10 or 11, characterized in that the polyamine is: I. an adduct of a diglycidyl ether amine based on bis (4-hydroxyphenyl) -2,2-propane; II. an adduct of an amine and dimethyl maleate; or III. an adduct of an amine prepared from a polyacrylate having at least two acrylate groups per molecule and having a molecular weight by weight of about 100 to 50,000.

13. The coating composition according to claim 1 or 2, characterized in that the polyketimine has a weight-average molecular weight in the range of 100 to 100,000.

14. A method for producing a coating on a substrate, the method is characterized in that it comprises: mixing a crosslinking component with a binder component to form a mixture of the container, the crosslinking component comprising a polyamine, a polyketimine, or a combination of the same, the polyamine having an average of at least two amine functionalities per polyamine molecule and the polyketimine having an average of at least two ketimine functionalities per polyketimine molecule; the binder component comprising a polyacetoacetate having at least two acetoacetate functionalities, the polyacetoacetate which is polymerized from a monomer mixture comprising a methacrylate monomer, a styrene monomer, or a combination thereof, the monomers of methacrylate and styrene each having a sloping, voluminous portion; apply a layer of the mixture of the container on the surface; and curing the layer under ambient conditions to form the coating on the surface of the substrate, the coating in a two hour cure has a Persoz hardness of approximately more than or equal to 60 for a dry film thickness of more than or equal to 40 microns.

15. The method according to claim 14, characterized in that the methacrylate monomer having the sloping, bulky portion is selected from the group consisting of isobornyl methacrylate, cyclohexyl methacrylate, t-butylcyclohexyl methacrylate, trimethylcyclohexyl methacrylate, methacrylate t -butyl and a combination thereof.

16. The method according to claim 14, characterized in that the styrene monomer having the sloping, bulky portion is t-butyl styrene.

17. The method according to claim 14, characterized in that the polyacetoacetate has a Tg in the range of 40 ° C to 150 ° C.

18. The method according to claim 14, characterized in that the substrate is a car body.