MX2008002936A - Coating composition and film system therefrom - Google Patents

Abstract

A coating composition is used to form a clearcoat layer of a film system including a basecoat layer and the clearcoat layer. The coating composition includes a carbamate functional polymer, a cross-linking agent reactive with the carbamate functional polymer, and an acid functional polymer substantially non-reactive with the carbamate functional polymer and the cross-linking agent. The acid functional polymer has an acid value of at least 50 mg KOH/g and contributes to an increased resistance to acid etch of the clearcoat layer. The acid functional polymer also contributes to an increased intercoat adhesion of the basecoat layer and the clearcoatlayer thereby decreasing a possibility of separation/delamination of the basecoat layer and the clearcoat layer.

Description

COMPOSITION OF COATING AND FILM SYSTEM FROM THIS FIELD OF THE INVENTION The present invention relates to a coating composition containing an acid functional polymer having an acid number of at least 50 mg KOH / g. The present invention also relates to a film system that includes a base coat layer and a transparent coating layer that is formed from the coating composition.

DESCRIPTION OF THE RELATED ART The coating compositions which include acid functional polymers are well known in the art. Acid functional polymers usually increase a resin dispersion in aqueous coating compositions or act as crosslinkers in carboxy-epoxy coating compositions. However, acid functional polymers are not normally used in coating compositions containing carbamate functional polymers and have not been shown to increase acid etch resistance of cured coating compositions including carbamate functional polymers.

Coating compositions containing carbamate functional polymers and crosslinking agents that are reactive with the carbamate functional polymers are also well known in the art. These coating compositions are particularly desired for use in automotive paint applications in view of the fact that they can be cured to form transparent coating layers and base coat (paint) layers which can serve as final finishing layers and exhibit durability, hardness and uniform appearance. However, the final finishing layers may be susceptible to the chemical attack of acid rain. Acid rain can also hydrolyze the exposed ether linkages that are formed between any of the hydroxyl functional polymer sites present, such as those of the carbamate functional polymers, and the crosslinking agents. When this occurs, defects (eg imperfections and stains) are formed in the clearcoat layers and are not easily removed. In addition, many of the basecoat / repair clearcoat layers are particularly susceptible to lamination from the underlying basecoats / clearcoat layers in view of the fact that they present a reduced intercoat adhesion to the basecoat layers, giving as a result, deficient durability and hardness and inconsistent appearance.

During the past, efforts have been made to improve the acid etch resistance and intercoat adhesion of the clearcoat layers to improve their usability and to improve the commercial convenience of acquiring the coating compositions that are used to form the coats of layers. transparent coating. One such effort, described in US Patent No. 5,593,785 to Mayo et al., Describes a film-forming composition that includes a double resin system and a crosslinking agent. The double resin system includes a carbamate functional acrylic polymer and a polyester polymer, while the crosslinking agent is a plastic amino. In this double resin system, the crosslinking agent reacts (i.e., crosslinked) with the carbamate functional acrylic polymer and the polyester to form the clear coating layer. Specifically, the polyester of the '785 Patent has a variable molecular weight, a numerical average and a weighted variable functionality and a wide polydispersity.These features, and especially the carbamate functionality, adversely affect the polyester polymer and do not allow the polymer The polyester polymer functions as a separate, mobile, non-reactive functional acidic polymer, as such, the polyester polymer must be used in increased amounts as a reactant in the double resin system, compared to any amount of the separate, mobile functional acid polymer and not reagent that could be used as an additive.

Accordingly, the opportunity remains to form a coating composition containing a functional acidic polymer having a particular acid number. There is also the opportunity to form a coating composition which, when cured, improves resistance to acid attack. There is also the opportunity to form a film system that includes a basecoat layer and a clearcoat layer that are formed from the coating composition having improved intercoat adhesion between the clearcoat layer and the basecoat layer. .

SUMMARY OF THE INVENTION AND ADVANTAGES The present invention provides a coating composition that includes a carbamate functional polymer (A), a crosslinking agent (B) reactive with the functional carbaraate polymer (A). The coating composition also includes an acid functional polymer (C) that is considerably more reactive with the carbamate functional polymer (A) and the crosslinking agent (B). The acid functional polymer (C) has an acid number of at least 50 mg KOH / g. The present invention also provides a film system that includes a base coat layer and a clear coat layer that are formed from the coating composition once cured.

The functional acidic polymer (C) contributes to an increased resistance to acid attack of the transparent coating layer in a cost effective manner. The increased resistance to acid attack reduces a potential for defect formation in the transparent coating layer due to acid rain, thereby improving the appearance and utility of the transparent coating layer and the commercial convenience of acquiring the coating composition that is Use to form the transparent coating layer. The functional acidic polymer (C) also contributes to improved intercoat adhesion of the basecoat layer and the clearcoat layer. The increased intercoat adhesion decreases a possibility of separation / delamination of the clearcoat layer from the basecoat layer resulting in increased durability, hardness and appearance of the clearcoat layers and the basecoat layer. The functional acidic polymer (C) further contributes to leveling the coating composition during application, evaporation and curing.

DETAILED DESCRIPTION OF THE PREFERRED MODALITY The present invention provides a coating composition that can be aqueous or solvent. Preferably, the coating composition is carried by solvent and has a water content of less than 1% by weight. The coating composition includes a carbamate functional polymer (A), a crosslinker (B) reactive with the carbamate functional polymer (A), and an acid functional polymer (C) that is practically unreactive with the carbamate functional polymer (A) and the crosslinking agent (B). The crosslinking agent (B) and the acid functional polymer (C) are described in more detail below. The present invention also provides a film system that includes a base coat layer and a clear coat layer that are formed from the once cured coating composition, each also described in greater detail below.

The carbamate functional polymer (A) can be any carbamate functional polymer (A) known in the art. The carbamate functional polymer (A) includes at least one carbamate functional group and may include more than one carbamate functional group. For purposes of the description only, a chemical structure of the carbamate functional group is illustrated below.

The carbamate functional polymer (A) may also include one or more functional groups selected from the group of esters, ethers, ketones, aldehydes, carboxylic acids, amides and ureas, acrylics, groups that include sulfur, groups that include phosphorus, groups that include silane and mixtures thereof. The carbamate functional polymer (A) may also include aliphatic, cycloaliphatic and aromatic groups. In one embodiment, the carbamate functional polymer (A) includes a branched organic structure having various functionalities including, but not limited to, branched hydrocarbon functionality, hydroxyl functionality, carboxylate functionality, carbamate functionality and ester functionality. Preferably, the carbamate functional polymer (A) has a number average molecular weight of from 1,000 to 20,000, more preferably from 2,000 to 8,000 and more preferably from 3,000 to 5,000 g / mol. However, it should be understood that the carbamate functional polymer (A) can have any molecular weight.

Preferably, the carbamate functional polymer (A) is included in an amount of 20 to 80, more preferably from 30 to 70, more preferably from 40 to 50 parts by weight per 100 parts by weight of the coating composition. However, the carbamate functional polymer (A) may be included in the coating composition in any amount.

The carbamate functional polymer (A) can also be formed by any process known in the art. In one embodiment, the carbamate functional polymer (A) is formed from a method that includes the preparation of a skeleton polymer that includes one or more functional groups by addition, which includes polymerizing one or more carbamate-free monomers, with unsaturation ethylenic and one or more non-functional monomers, with ethylenic unsaturation, and reacting the backbone polymer with one or more additional reactive compounds to produce the carbamate functional polymer (A) having at least one carbamate group, as described in the Patent No. 6,696,535 which is expressly incorporated herein by reference. In another embodiment, the carbamate functional polymer (A) is formed from a method as described in US Patent No. 6,855,789, which is also expressly incorporated herein by reference. In yet another embodiment, the carbamate functional polymer (A) includes the reaction product of a compound comprising a plurality of hydroxyl groups, at least one of which is formed from a ring-opening reaction of an epoxy group and an organic acid, and a compound including a carbamate group, as set forth in US Patent No. 6,420,472, which is also expressly incorporated herein by reference. In still another embodiment, the carbamate functional polymer (A) is a reaction product of a first compound having a plurality of hydroxyl groups, a primary carbamate compound and a silyl compound having a terminal group reactive with hydroxyl groups and also having silylalkoxy groups. In another embodiment, the carbamate functional polymer (A) is more specifically the product of the reaction of the first compound having the plurality of hydroxyl groups, a carboxylic acid anhydride, a second compound having at least one epoxy group, the compound primary carbamate and the silyl compound having the terminal group reactive with the hydroxyl groups and having silylalkoxy groups.

The coating composition may also include an additional carbamate functional compound, i.e., a carbamate functional modifier that is different from the carbamate functional polymer (A), such as a carbamate functional resin, a carbamate functional oligomer and other compounds. It is also contemplated that more than one additional carbamate functional compound may be included in the coating composition. The additional functional carbamate compound, such as the carbamate functional polymer (A), can be any known in the art and can be formed by any method known in the art. The functional carbamate compound can also be reacted with the crosslinking compound. If included, the functional carbamate compound is preferably included in an amount of 3 to 25, more preferably 6 to 18 and more preferably 10 to 14 parts by weight per 100 parts by weight of the coating composition. However, the carbamate functional compound can be included in the coating composition in any amount, as determined by one skilled in the art.

With reference now to the crosslinking agent (B), the crosslinking agent (B) is reactive with the carbamate functional polymer (A) and can be reactive with any of the carbamate functional compounds, as mentioned above. In one embodiment, the crosslinking agent (B) includes a melamine formaldehyde resin. In another embodiment, the crosslinking agent (B) includes monomeric and polymeric formaldehyde melamine resins, which includes partially and completely alkylated melamines such as methylated melamines, butylated melamines and methylated / butylated melamines. In still another embodiment, the crosslinking agent (B) includes a first and a second melamine formaldehyde resin. In this embodiment, the first melamine formaldehyde resin is present in an amount of 2.5 to 4.5 parts by weight per 100 parts by weight of the coating composition and is a fully methylated melamine. As such, the first melamine formaldehyde resin includes alkoxymethyl groups of the general formula -CH2ORi, where Ri is an alkyl chain having from 1 to 20 carbon atoms. The first melamine formaldehyde resin most preferred in this embodiment is exametoxymethylmelamine and is available commercially from Cytec Industries of Wallingford, CT. Also in this embodiment, the second melamine formaldehyde resin is present in an amount of 2.5 to 20 parts by weight and is a partially methylated melamine. As such, the second melamine formaldehyde resin can include a methylol group, CH20H, and alkoxymethyl groups, -CH2ORi, as already defined. In this embodiment, the weight ratio of the first melamine formaldehyde resin to the second melamine formaldehyde resin is from 1: 5 to 5: 1, and more preferably from 1: 2 to 2: 1. It is envisaged that the cross-linking agent (B) may be any of those known in the art.

In another embodiment, the cross-linking agent (B) is selected from the group of amine plastics, phenolic adducts, siloxanes, silanes, alkyloles, isocyanates, acrylics, anhydrides and combinations thereof. A non-limiting example of an appropriate plastic amino, in addition to the melamine formaldehyde resins described above, includes a urea formaldehyde resin. A non-limiting example of a siloxane includes trimethoxysiloxane. Non-limiting examples of the alkyls include methylol ureas. Non-limiting examples of isocyanates include aliphatic and aromatic isocyanates, and the modified polyisocyanates include ureas, biurets, allophanates, carbodiimides, uretonimines, and isocyanurate and / or urethane groups including diisocyanates and / or polyisocyanates such as modified diphenylmethane diisocyanates. The isocyanate can be a blocked or an unblocked polyisocyanate. Non-limiting examples of the appropriate blocking agents include those materials that are deblocked at elevated temperatures such as caprolactam. Other suitable blocking agents include, but are not limited to, phenol, cresols, isononylphenol, oximes such as methyl ethyl ketoxime and butanone oxime, compounds containing active methylene group, diethyl malonate and isopropylidene malonate, acetoacetates and sodium bisulfite. A non-limiting example of an anhydride includes polysuccinic anhydride.

Preferably, the crosslinking agent (B) is present and is included in an amount of 0.5 to 15, and more preferably 5 to 9 parts by weight per 100 parts by weight of the coating composition. However, it should be understood that the crosslinking agent (B) may be present in the coating composition in any amount, as determined by one skilled in the art. The coating composition also includes the functional acidic polymer (C) which is practically unreactive with the carbamate functional polymer (A) and the crosslinking agent (B), as mentioned above. For the purpose of the present invention, the term "substantially nonreactive" includes a common reaction of carbamate to melamine or hydroxyl to melamine which is negligible and unnecessary in the contribution to the crosslinking density or Tg of curing necessary to achieve the properties adequate physical In one embodiment, the functional acidic polymer (C) is totally unreactive with the carbamate functional polymer (A) and the crosslinking agent (B).

The functional acidic polymer (C) may be any known in the art provided that the functional acidic polymer (C) has an acid number of at least 50 mg KOH / g. The functional acidic polymer (C) is also considered. it may have the ability to migrate at least partially to a surface of the composition and / or transparent coating layer. In one embodiment, the functional acidic polymer (C) has an acid number of at least 120 mg KOH / g. In another embodiment, the functional acidic polymer (C) has an acid number of at least 240 mg KOH / g. In still another embodiment, the functional acidic polymer (C) has an acid number of 240 to 250 mg KOH / g. The introduction of the functional acidic polymer (C) unexpectedly increases an acid attack resistance of a cured film layer and / or the transparent coating layer that is formed from the coating composition. The introduction also increases adhesion between layers of the cured film layer and / or the transparent coating layer with the base coating layer. In addition, the inclusion reduces and preferably eliminates the need to include a leveling agent in the coating composition in view of the fact that the functional acidic polymer (C) can also serve as the leveling agent. The acid functional polymer (C) has a precise molecular weight, but a weighted and numerical average, a narrow functionality dispersion and a narrow polydispersity. Each of these characteristics allows the precise design of the functional acidic polymer (C) for different applications, as determined by one skilled in the art and contributes to the increased acid resistance and adhesion between layers.

In one embodiment, the functional acidic polymer (C) includes an acrylic polymer. The acrylic polymer may be any known in the art and may include an acrylic polyester. In another embodiment, the functional acidic polymer (C) includes a polyalkyl acrylate. Preferably, the polyalkyl acrylate includes polybutylacrylate. In still another embodiment, the functional acidic polymer (C) consists of a polyester polymer. In all embodiments, the functional acidic polymer (C) can include any structure, provided that the acid number of the functional acidic polymer (C) is at least 50 mg KOH / g. In one embodiment, the functional acidic polymer (C) includes a star polyester containing polyacrylate side chains. In another embodiment, the functional acidic polymer (C) includes a hybrid polyester copolymerized with a polybutylacrylate.

Preferably, the functional acidic polymer (C) has a density of 1.02 to 1.05, and more preferably 1.02 to 1.04 g / cm3. The functional acidic polymer (C) also preferably has a viscosity of from 90 to 1200, and more preferably from 180 to 200 MPa.s. at 25 ° C. The functional acidic polymer (C) also preferably has a weight average molecular weight of 3500 to 20,000, and more preferably of 5500 to 20,000 g / mol, and a number average molecular weight of 1500 to 6500, and more preferably 2000 to 6500 g / mol. The functional acidic polymer (C) also preferably has a solids percentage of 45 to 60, and more preferably 49 to 59%. Preferably, the functional acidic polymer (C) also has a refractive index of from 1.4 to 1.5, more preferably from 1.44 to 1.46, and more preferably from 1.44 to 1.45. Moreover, the functional acidic polymer (C) preferably has a pKa from 4 to 6. However, it should be understood that the functional acidic polymer (C) can have any density, viscosity, molecular weight, percent solids, refractive index. and pKa provided that the acid functional polymer (C) has an acid number of at least 50 mg KOH / g.

In relation again with the coating composition, the coating composition may also include an additive polymer. If so, the additive polymer is different from the functional acid polymer (C). However, the aforementioned description of the functional acidic polymer (C) can also be applied to the additive polymer. In one embodiment, the additive polymer includes a polyacrylate available commercially from King Industries of Norwalk, Connecticut under the trade name Disparlon® LAP-20.

The coating composition preferably includes at least one catalyst to improve curing. Preferably, when the crosslinking agent (B) includes the plastic amino, especially melamine, an acid catalyst can be used to improve curing. Such catalysts are well known in the art and include, but are not limited to, p-toluenesulfonic acid, dinonylnaphthalene disulfonic acid, dodecylbenzenesulfonic acid, phenyl acid phosphate, monobutyl maleate, butyl phosphate, hydroxyphosphate ester and combinations thereof. Other catalysts that may be useful in the coating composition of the invention may be, but are not limited to, Lewis acids, transition metal salts such as zinc salts and tin salts and combinations thereof. In general, the catalysts: (1) reduce a temperature necessary for the reaction between the carbamate functional polymer (A) and the crosslinking agent (B); or (2) they raise a reaction rate between the carbamate functional polymer (A) and the crosslinking agent (B), or both. In some cases, it may be desirable to reduce the reaction rate at ambient temperatures. The catalyst can be blocked, not blocked or partially blocked. The catalyst can be blocked or partially blocked with an amine or other suitable blocking agent as an oxirane modifying material. The amine, which is volatile, is an appropriate blocking agent because the amine is evaporated from the coating composition when it is cured thereby unblocking the catalyst due to the heat introduced by any traditional means, such as an oven, during curing. An unblocked acid catalyst suitable for use in the coating composition of the present invention is sold by King Industries of Norwalk, Connecticut under the trade name Nacure® 1051. If included, the catalyst is preferably included in an amount of 0.1 to 1.2. , more preferably from 0.1 to 0.9, and more preferably from 0.2 to 0.7 parts by weight per 100 parts by weight of the coating composition.

The coating composition further includes at least one additive other than the additive polymer. The at least one additive can be selected from the group consisting of leveling agents, surfactants, fillers, stabilizers, solvents, plasticizers, defoaming agents, wetting additives, catalysts, rheology controlling agents, pigments and combinations thereof. Non-limiting examples of suitable surfactants include Surfynol® Surfactants available commercially from Air Products and Chemicasl, Inc. of Allentown, PA. Suitable non-limiting examples of plasticizers include Coroc® Acrylic Plasticizer Resins available commercially from Cook Composites and Polymers of St. Louis, MO.

If the coating composition includes the solvent as an additive, the solvent preferably dissolves the carbamate functional polymer (A), the crosslinking agent (B) and the acid functional polymer (C) to a considerable degree. The solvent may include any organic solvent and / or water. In one embodiment, the solvent includes a polar organic solvent. In another embodiment, the solvent includes a polar aliphatic solvent. In a further embodiment, the solvent includes a polar aromatic solvent. In yet another embodiment, the solvent is selected from the group of a ketone, an ester, an acetate, an aprotic amide, an aprotic sulfoxide, an aprotic amine and combinations thereof. Non-limiting examples of the useful solvents include methyl ethyl ketone, methyl propyl ketone, methyl isobutyl ketone, m-amyl acetate, ethylene glycol butyl ether acetate, propylene glycol monomethyl ether acetate, xylene, N-methyl pyrrolidone, 2-ethylhexanol, N-butanol, dipropylene glycol methyl ether, solvent SC 150 commercially available from ExxonMobil of Irving, TX, naphtha, heavy benzene, ethyl ethoxypropionate, butyl glycol acetate, butyl glycol, mixtures of aromatic hydrocarbons and combinations thereof.

If the coating composition includes the pigment as an additive, for example, when the coating composition is used to form a base coat layer, the pigment may include organic and / or inorganic compounds, colored materials, fillers, metal flake materials and / or inorganic as mica or aluminum flakes, and combinations of these. Non-limiting examples of the appropriate pigments include a carbon black pigment, titanium dioxide and other colored inorganic pigments, such as iron oxide, chromium yellow, molybdenum orange, yellow titanium, yellow nickel titanate, green chromium and the like.

If the coating composition includes the leveling agent as an additive, the leveling agent may include, but is not limited to, vinyl acrylic copolymers, polyether polysiloxanes, hydroxyl functional, halogenated polysiloxanes, and combinations thereof. Illustrative, commercially available examples of these types of leveling agents include, but are not limited to, Byk 373 (hydroxyl polyether polydimethyl polysiloxane) available commercially from Byk Chemie of Wesel, Germany, Disparlon® LC 955 (vinyl acrylate copolymer) available commercially from Kyoeisha Chemical of Tokyo, Japan, Silwet® L-7614 (polysiloxane modified with polyether hydroxyl functional) available commercially from Chemtura Corporation of Middlebury, CT, and Addid® 761 (fluorinated polysiloxane) commercially available from Wacker Chemie AG of München, Germany.

If the coating composition includes the stabilizer as an additive, the stabilizer may include hindered amine light stabilizers (the HALs). If included, the HALs may include any of those known in the art. Demonstrative examples of commercially available HALs that are suitable for use in the present invention may be, but are not limited to, Sanduvor® 3058 available commercially from Clariant Corporation of Charlotte, NC, and Tinuvin® 292, available from trade of Ciba Specialty Chemicals Corporation of Basel, Switzerland.

The coating composition is preferably applied to a substrate, such as the bodywork of a vehicle, and cured to form a cured film layer. The cured film layer, for purposes of the present invention, can be used as a primer layer, the basecoat layer and / or the clearcoat layer, and can be applied to any film thickness. Preferably, if the cured film layer is used as a clear coating layer, it is applied in a film thickness of 1.2 to 2.5, more preferably 1.6 to 2.1 and more preferably 1.8 to 2.0 mils. If the cured film layer is used as a clear coating layer, the transparent coating layer preferably has gloss. In one embodiment, the clearcoat layer has a gloss at 20 ° of 80 or more (ASTM D523-89) or a DOI (ASTM E430-91) of at least 80. The use of the curable film layer as the The transparent coating layer will be described in more detail below.

The coating composition can be applied by any method known in the art. Suitable methods include, but are not limited to, spray coating, dip coating, roll coating, curtain coating and combinations thereof. The substrate can be any suitable substrate known in the art. In one embodiment, the substrate includes boards for automobile bodies. In another embodiment, the substrate is selected from the group of plastic, metals such as steel, iron and aluminum and combinations thereof. The substrate may be covered or uncoated, treated or untreated and combinations thereof. More preferably, the substrate is primed or electrocoated, and includes automobile body panels.

After the coating composition is applied to the substrate, the substrate is preferably subjected to conditions to cure the coating composition and form the cured film layer, as mentioned above.

Although it is possible to use different curing methods, heat curing is preferred. In general, heat curing is effected by exposing the substrate to elevated temperatures provided primarily by sources of radiant heat. However, with the present invention it is possible to use any type of curing. Preferably, the coating composition is cured at a temperature of 230 ° F to 320 ° F (109 ° C to 158 ° C) to form the cured film layer. If the coating composition includes a blocked acid catalyst, the coating composition is most preferably cured at a temperature of 250 ° F to 300 ° F (120 ° C to 147 ° C), and more preferably at a temperature of 275 ° C. F at 285 ° F (134 ° C to 139 ° C) to form the cured film layer. If the coating composition contains an unblocked acid catalyst, the coating composition is most preferably cured at a temperature of 180 ° F to 220 ° F (82 ° C to 103 ° C) to form the cured film layer.

The coating composition is preferably cured for a time of 3 minutes to 60 minutes. However, if the coating composition includes a blocked acid catalyst, the coating composition is more preferably cured for a time of 15 to 25 minutes. If the coating composition includes an unblocked acid catalyst, the coating composition is more preferably cured for a time of 10 to 20 minutes.

After curing and the formation of the cured film layer, the cured film layer preferably has a Jacksonville Etch of less than 7, more preferably less than 5, even more preferably 3 to 5, and more preferably 3 or less , as determined by the material specification G # 9984157. The present invention may also include a process for coating the substrate using the coating composition.

The present invention also provides the film system including the base coat layer and the clear coat layer that is formed from the once cured coating composition, as mentioned above. The basecoating composition may include a polymer selected from the group of acrylics, vinyls, polyurethanes, polycarbonates, polyesters, alkyds, polysiloxanes, and combinations thereof. Preferred polymers include acrylics and polyurethanes. The polymer is crosslinkable and includes one or more types of crosslinkable functional groups. Crosslinkable groups such as these may be, but are not limited to, hydroxy, isocyanate, amine, epoxy, acrylate, vinyl, silane, acetoacetate groups and combinations thereof. These crosslinkable groups can be masked or blocked in such a way so that they are unblocked and available to crosslink under the desired curing conditions, as also described above. The present invention may also include the substrate having the film system applied thereto.

Referring now to the transparent coating layer, the transparent coating layer is preferably applied at a film thickness of 1.2 to 2.5, more preferably 1.6 to 2.1, and more preferably 1.8 to 2.0 mils. The clear coating layer also preferably has gloss. In one embodiment, the transparent coating layer has a brightness at 20 ° of 80 or more (AST D523-89) or a DOI (ASTM E-430-91) of at least 80, as already described. The clearcoat layer also preferably has a Jacksonville Etch of less than 7, more preferably less than 5 and more preferably 3 to 5, as mentioned above and as determined by the material specification GM # 9984157.

Referring now to the basecoat layer and the clearcoat layer, the basecoat layer and the transparentcoat layer preferably have an interlayer adhesion to a clear film coating of at least 1.6 mils for failure as described above. determined by the GM 9071P test number. In one embodiment, the basecoat layer and the transparentcoat layer are used as repair and original layers, respectively, and have an interlayer adhesion of about 3.3, as also determined by test number GM 9071P. Preferably, the basecoat layer and the clearcoat layer have an adhesion percentage of at least 95%, as further determined by the test number GM 9071P. In one embodiment, the basecoat layer and the transparentcoat layer have an adhesion percentage of 95 to 100%. In yet another embodiment, the basecoat layer and the transparentcoat layer have an adhesion percentage of 100%.

The following examples demonstrate the formation and use of the carbamate functional polymer (A), the crosslinking agent (B) and the acid functional polymer (C) of the present invention, as shown herein, are intended to illustrate and not limit the invention.

EXAMPLES Four coating compositions, Coating Composition 1 through 4, are formulated in accordance with the present invention. Two comparative coating compositions, Comparative Coating Compositions 1 and 2, are also formulated but do not include the functional acidic polymer (C) of the present invention. Each of the Coating Compositions 1 to 4 and Comparative Coating Compositions 1 and 2, after forming, are used to form clearcoat layers, Coating Coats 1 to 4 and Coating Coats Transparent Coating 1 and 2, respectively. Transparent Coating Coats 1 to 4 and Comparative Coating Coats 1 and 2 are evaluated for acid attack resistance, intercalated adhesion and percent adhesion, with the basecoat layers described in greater detail below.

Example 1: To formulate the coating composition 1, the following parts are added to an appropriate vessel equipped with agitation: 77. 570 g of a high solids carbamate acrylic resin, manufactured for trade by BASF Corporation of Southfield, MI; 22. 030 g of diol carbamate, made commercially from BASF Corporation of Southfield, MI; 34. 510 g of butylated formaldehyde melamine resin, commercially available from BASF Corporation of Ludwigshafen Germany, under the tradename of Luwipal® 018, as a cross-linking agent (B); 0. 400 g of a functional acidic polymer 1 having a solids percentage of 49.8%, an acid number of 248.6 mg KOH / g, a weight average molecular weight of 19, 993 g / mol and a number average molecular weight of 6394 g / mol; . 240 g of Aerosoil® R972, a dispersion of 9.8% R972 and 28% of solid carbamated acrylic resin and a solvent, is available commercially from Deggusa Corporation of Parsippany, NJ, as a first additive; . 000 g of Tinuvin® 384-2, available commercially from Ciba-Geigy Corporation of Ardsley, NY, as a second additive; 1. 500 g of Tinuvin® 123, available commercially from Ciba-Geigy Corporation of Ardsley, NY, as the third additive; and 2,800 g of Nacure® 5225, available commercially from King Industries of Norwalk, Connecticut, as a catalyst, as set forth in Table 1 below.

Example 2: To formulate Coating Composition 2, the aforementioned parts used to form Coating Composition 1 are used in the same way except that 0.400 g of Functional Acid Polymer 2 are replaced by Functional Acid Polymer 1, as well as set forth in Table 1 below. Functional Acid polymer 2 has a solids percentage of 58.3%, an acid number of 245.5 mg KOH / g, a weight average molecular weight of 6.940 g / mol and a number average molecular weight of 3100 g / mol.

Example 3: To formulate Coating Composition 3, the aforementioned parts that were used to form Coating Composition 1 are used in the same way except that 0.400 g of a Functional Acid Polymer 3 are substituted for Functional Acid Polymer 1, as also set forth in Table 1 below. The Functional Acid Polymer 3 has a solids percentage of 49.0%, an acid number of 121.3 mg KOH / g, a weight average molecular weight of 5.611 g / mol and a number average molecular weight of 2300 g / mol, a viscosity of 191 MPa.s at 25 ° C, a density of 1.027 g / cm3 and a refractive index of 1.4482.

Example 4 To formulate Coating Composition 4, the aforementioned parts that were used to form Coating Composition 1 are used in the same way, except that 0.400 g of a Functional Acid Polymer 4 are replaced by Functional Acid Polymer 1, as also set forth in Table 1 below. Functional Acid Polymer 4 is an ionic acrylic copolymer having a density of 1.03 g / cm 3, a refractive index of 1,452 and an acid number of 80 mg KOH / g.

Comparative Example 1 To formulate the Comparative Coating Composition 1, the following parts are added to an appropriate vessel equipped with agitation: 77. 570 g of a high solids carbamate acrylic resin, manufactured for trade by BASF Corporation of Southfield, MI, as a carbamate functional polymer (A); . 030 g of carbamate diol, made commercially from BASF Corporation of Southfield, MI, as a carbamate-functional compound; 34. 510 g of butylated formaldehyde melamine resin, commercially available from BASF Corporation of Ludwigshafen Germany, under the tradename of Luwipal® 018, as a cross-linking agent (B); 0. 400 g of Disparlon®, available commercially from Kyoeisha Chemical of Tokyo, Japan, as leveling agent; . 240 g of Aerosoil® R972, available commercially from Degussa Corporation of Parsippany, NJ, as a first additive; . 000 g of Tinuvin® 384-2, available commercially from Ciba-Geigy Corporation of Ardsley, NY, as a second additive; 1. 500 g of Tinuvin® 123, available commercially from Ciba-Geigy Corporation of Ardsley, NY, as the third additive; and 2.8 g Nacure® 5225, available commercially from King Industries of Norwalk, Connecticut, as a catalyst, as set forth in Table 1 below.

Comparative Example 2: To formulate the Comparative Coating Composition 2, the aforementioned parts used to form the Comparative Coating Composition 1 are used in the same way except that 2.24 g of Nacure® 5225 is used as a catalyst, as also stated in Table 1 below. In Table 1, all parts are in grams.

TABLE 1 TABLE 1 (CONTINUED) After the formation of Coating Compositions 1 through 4 and Comparative Coating Compositions 1 and 2, 14,000 g of ethylene glycol mono utilether acetate was available commercially from the Dow Chemical Company of Midland, MI, as the first solvent, and 10,100 g of Hi-Sol 10, available commercially from Ashland Inc., of Covington, KY as a second solvent, are added to each of Coating Compositions 1 through 4 and Comparative Coating Compositions 1 and 2. The first and second solvents are added in the spray preparation of each of the Coating Compositions 1 to 4 and the Comparative Coating Compositions 1 and 2 on electro-coated and primed ACT panels or boards, separated including the basecoat layers, before mentioned.

Specifically, to form the basecoat layers, the electrocoated and primed ACT boards are sprayed with a white, aqueous basecoating composition, commercially available from BASF Corporation under the tradename E54WW403, for a film build of from 0 to 2.5. mils on an accumulated film ladder. The boards are then pre-baked in a traditional oven at a temperature of 300 ° F and for a time of 90 minutes, thereby forming the basecoat layers. After the formation of the basecoat layers, Coating Compositions 1 to 4 and Comparative Coating Compositions 1 and 2 each are sprayed individually on different boards in the series of a film build of from 0 to 2.5 mils in a film accumulation ladder, and cured in a regular oven at 275 ° F for 25 minutes to form the Clear Coating Coats 1 to 4 and the Comparative Clear Coating Coats 1 and 2, respectively. Transparent Coating Coats 1 to 4 and Comparative Coating Coating Coats 1 and 2 are then evaluated for acid etch resistance (Jacksonville Etch) determined by GM material specification 9984157, Film build-up for failure of total coatings. basecoat to the clearcoat layers (ie, interlayer adhesion between Clear Coats 1 to 4 and Comparative Clear Coats 1 and 2, with basecoat coats), determined by GM test number 9071P, and the percent adhesion determined by GM 9071P test number, as set forth in Table 2 below.

TABLE 2 TABLE 2 (continued) As shown in Table 2, the Jacksonville Etch Test of Clear Coating Compositions 1 through 4 is smaller than the Jacksonville Etch Test of Comparative Clear Coating Coats 1 and 2, demonstrating that Clear Coating Coats 1 to 4 are more resistant to acid attack, the formation of spots and imperfections of acid rain. As also shown in Table 2, the film buildup for failure of Clear Coating Layers 1 through 4 is greater than the film buildup for failure of Clear Coating Layers Comparatives 1 and 2, demonstrating that Transparent Coating Coats 1 to 4 are more resistant to lamination and separation of basecoat layers than Comparative Coating Coating Coats 1 and 2. As further shown in Table 2, the adhesion percentage of The Clear Coating Layers 1 to 4 is greater than the adhesion percentage of the Comparative Clear Coating Layers 1 and 2, demonstrating that the Coating Layers 1 to 4 have an increased cohesion with the base coat layers. These results indicate that Clear Coating Coats 1 to 4 are suitable for commercial use in automotive paint applications, while Coating Clear Coats 1 and 2 are less suitable for this use.

The invention has been described in an illustrative form, and it should be understood that the terms that have been used are intended to be description rather than limitation. Of course, multiple modifications and variations of the present invention are possible in light of the above teachings, and the invention can be practiced otherwise than specifically described.

Claims (32)

1. A coating composition containing: A. A functional carbamate polymer; B. a crosslinking agent reactive with the carbamate functional polymer; and C. a functional acidic polymer that is substantially unreactive with the carbamate functional polymer (A) and the crosslinking agent (B), the functional acidic polymer has an acid number of at least 50 mg KOH / g.

2. The coating composition as set forth in claim 1, characterized in that the acid functional polymer (C) has an acid number of at least 120 mg KOH / g.

3. The coating composition as set forth in claim 1, characterized in that the functional acidic polymer (C) has an acid number of at least 240 mg KOH / g.

4. The coating composition as set forth in claim 1, characterized in that the functional acidic polymer (C) consists of an acrylic polymer.

5. The coating composition as set forth in claim 4 characterized in that the acrylic polymer consists of an acrylic polyester.

6. The coating composition as set forth in claim 1, characterized in that the functional acidic polymer consists of a polyalkyl acrylate.

7. The coating composition as set forth in claim 6 characterized in that the polyalkyl acrylate consists of polybutylacrylate.

8. The coating composition as set forth in claim 1, characterized in that the functional acidic polymer (C) consists of a polyester polymer.

9. The coating composition as set forth in claim 1, characterized in that the carbamate functional polymer (A) consists of the product of the reaction of: A. A compound having a plurality of hydroxyl groups, at least one of which is formed from a ring opening reaction of an epoxy group and an organic acid; B. a compound that includes a carbamate group.

10. The coating composition as set forth in claim 1, characterized in that the crosslinking agent (B) is selected from the group of amine plastics, phenolic adducts, siloxanes, silanes, alkylols, isocyanates, acrylics, anhydrides and combinations thereof.

11. The coating composition as set forth in claim 1, characterized in that the crosslinking agent (B) consists of a melamine formaldehyde resin.

12. The coating composition as set forth in claim 1 further comprises at least one catalyst in an amount of 0.1 to 0.9 parts by weight per 100 parts by weight of the coating composition.

13. The coating composition as set forth in claim 1 further comprises at least one additive selected from the group consisting of leveling agents, surfactants, fillers, stabilizers, solvents, plasticizers, defoaming agents, wetting additives, catalysts, controlling agents, the rheology, pigments and combinations of these.

14. The coating composition as set forth in claim 1 further comprises a carbamate functional compound different from the carbamate functional polymer (A).

15. The coating composition as set forth in claim 1 further comprises an addictive polymer.

16. The coating composition as set forth in claim 1, which produces, upon curing, a cured film layer having a Jacksonville Etch test of 3 to 5 as determined by the material specification GM 9984157.

17. The coating composition as set forth in claim 1, which is carried by solvent.

18. The coating composition as set forth in claim 1, which is aqueous.

19. A process for coating a substrate using the coating composition as set forth in claim 1.

20. A film system consisting of a base coat layer and a transparent coating layer formed from a coating composition once cured and consists of: A. the reaction product of; (i) a carbamate functional polymer, and (ii) a crosslinking agent reactive with the carbamate functional polymer; and B. a functional acidic polymer that is practically unreactive with (i) the carbamate functional polymer, (ii) the crosslinking agent, and the reaction product of (i) and (ii), the functional acidic polymer having an index of acidity of at least 50 mg KOH / g.

21. The film system as set forth in claim 20, characterized in that the functional acidic polymer (B) has an acid number of at least 120 mg KOH / g.

22. The film system as set forth in claim 20, characterized in that the functional acidic polymer (B) has an acid number of at least 240 mg KOH / g.

23. The film system as set forth in claim 20, characterized in that the functional acidic polymer (B) consists of an acrylic polymer.

24. The film system as set forth in claim 20 characterized in that the functional acidic polymer (B) comprises polybutylacrylate.

25. The film system as set forth in claim 20, characterized in that the carbamate functional polymer (i) consists of the reaction product: A. a compound containing a plurality of hydroxyl groups, at least one of which is formed from of a ring opening reaction of an epoxy group and an organic acid, and B. a compound including a carbamate group.

26. The film system as set forth in claim 20, characterized in that the crosslinking agent (ii) consists of a melamine formaldehyde resin.

27. The film system as set forth in claim 20, characterized in that the coating composition also contains a carbonate functional solvent solvent of the carbamate functional polymer (i) ·

28. The film system as set forth in claim 20, characterized in that the coating composition further comprises an additive polymer.

29. The film system as set forth in claim 20, characterized in that the transparent coating composition has a Jacksonville Etch test of 3 to 5 as determined by the material specification G 9984157.

30. The film system as set forth in claim 20, characterized in that the base coat layer and the transparent coating layer have an interlayer adhesion of at least 1.6 mils film buildup to the failure as determined by the GM test number. 9071P.

31. The film system as set forth in claim 20, characterized in that the base coat layer and the transparent coating layer have an adhesion percentage from 95 to 100%, as determined by the test number GM 9071P.

32. A substrate having the film system claim 20 applied thereto.