阅读说明：本技术 含有包括非水分散体的流变改性剂的可固化成膜组合物 (Curable film-forming compositions containing rheology modifiers including non-aqueous dispersions ) 是由 曹斌 D·R·芬恩 D·A·辛普森 王苇 M·S·卢查恩斯基 C·慧 I·Y·冈萨雷斯 于 2020-04-13 设计创作，主要内容包括：提供了一种可固化成膜组合物,其包括：(a)聚合粘合剂,其包括环氧官能团；(b)固化剂,其包括与(a)的所述环氧官能团反应的酸官能团；(c)非水分散体,其包括反应混合物的分散聚合反应产物,所述反应混合物包括烯键式不饱和单体和非线性无规丙烯酸类聚合物稳定剂；和(d)气相二氧化硅。以所述可固化成膜组合物中的树脂固体的总重量计,所述非水分散体(c)中的所述分散聚合反应产物以0.5到10重量％的量存在于所述可固化成膜组合物中,并且所述气相二氧化硅(d)以0.5到5重量％的量存在。还提供了包含上述可固化成膜组合物的多层涂覆制品。(Provided is a curable film-forming composition comprising: (a) a polymeric binder comprising epoxy functional groups; (b) a curing agent comprising an acid functional group that reacts with the epoxy functional group of (a); (c) a non-aqueous dispersion comprising the dispersion polymerization reaction product of a reaction mixture comprising ethylenically unsaturated monomers and a nonlinear random acrylic polymer stabilizer; and (d) fumed silica. The dispersion polymerization reaction product in the non-aqueous dispersion (c) is present in the curable film-forming composition in an amount of 0.5 to 10 weight percent and the fumed silica (d) is present in an amount of 0.5 to 5 weight percent, based on the total weight of resin solids in the curable film-forming composition. Also provided are multilayer coated articles comprising the curable film-forming composition described above.)

1. A curable film-forming composition comprising:

(a) a polymeric binder comprising epoxy functional groups;

(b) a curing agent comprising an acid functional group that reacts with the epoxy functional group of (a);

(c) a non-aqueous dispersion comprising the dispersion polymerization reaction product of a reaction mixture comprising ethylenically unsaturated monomers and ethylenically unsaturated nonlinear random acrylic polymer stabilizer, wherein the dispersion polymerization reaction product in the non-aqueous dispersion is present in the curable film-forming composition in an amount of from 0.5 to 10 weight percent based on the total weight of resin solids in the curable film-forming composition, and wherein the dispersion polymerization reaction product is different from the polymeric binder (a); and

(d) fumed silica present in the curable film-forming composition in an amount of 0.5 to 5 weight percent based on the total weight of resin solids in the curable film-forming composition.

2. The curable film-forming composition of claim 1, wherein the polymeric binder (a) comprises an acrylic and/or polyester polymer.

3. The curable film-forming composition of claim 1, wherein the curing agent (b) comprises an acid functional polyester or an acrylic polymer.

4. The curable film-forming composition of claim 1, wherein the acrylic polymeric stabilizer is prepared from a multifunctional ethylenically unsaturated monomer.

5. The curable film-forming composition of claim 4, wherein the multifunctional ethylenically unsaturated monomer comprises allyl (meth) acrylate and/or alkylene glycol di (meth) acrylate.

6. The curable film-forming composition of claim 1, wherein the acrylic polymeric stabilizer is prepared from a reaction mixture comprising 90 or more weight percent of (meth) acrylic monomers.

7. The curable film-forming composition of claim 1, wherein the acrylic polymeric stabilizer is prepared from a reaction mixture comprising 95 or greater weight percent of (meth) acrylic monomers.

8. The curable film-forming composition of claim 1, wherein the reaction mixture used to prepare the dispersion polymerization reaction product further comprises an aliphatic polyester stabilized seed polymer.

9. The curable film-forming composition of claim 1, wherein the dispersion polymerization product in the non-aqueous dispersion has an average particle size of 500nm or less.

10. The curable film-forming composition of claim 1, wherein the dispersion polymerization reaction product in the non-aqueous dispersion (c) and the fumed silica (d) are present in the curable film-forming composition in a total amount of 1 to 15 weight percent, based on the total weight of resin solids in the curable film-forming composition.

11. A multilayer coated article comprising a first film-forming composition applied to a substrate to form a colored base coat layer and a second transparent film-forming composition applied on top of the base coat layer to form a transparent top coat layer, wherein the transparent film-forming composition comprises the curable film-forming composition of claim 1.

12. The multilayer coated article of claim 11 wherein the polymeric binder (a) comprises an acrylic and/or polyester polymer.

13. The multilayer coated article of claim 11 wherein the curing agent (b) comprises an acid functional polyester or an acrylic polymer.

14. The multilayer coated article of claim 11, wherein the stabilizer is prepared from a multifunctional ethylenically unsaturated monomer.

15. The multilayer coated article of claim 11, wherein the transparent film-forming composition further comprises a colloidal silica different from the fumed silica.

16. The multilayer coated article of claim 11 wherein the dispersion polymerization product of the non-aqueous dispersion (c) and the fumed silica (d) are present in the curable film-forming composition in a total amount of 1 to 15 weight percent, based on the total weight of resin solids in the transparent film-forming composition.

Technical Field

The present invention relates to curable film-forming compositions comprising non-aqueous dispersions.

Background

Color-plus-clear coating systems involve applying a colored or pigmented basecoat to a substrate, followed by a clear topcoat to the basecoat, which is an industry standard for automotive original finishes. Color plus clear systems have excellent gloss and distinctness of image, and clear topcoats are particularly important for these properties.

Typically, during application of the coating to an automotive substrate, which is typically accomplished by spraying, the appearance of the coating (e.g., its smoothness) is different when applied to a horizontally oriented substrate surface than when applied to a vertically oriented surface. This can result in a distinct difference in surface appearance in different areas of the same vehicle. Efforts to balance processability and appearance of formulated coatings, as well as developing means to improve coating flow and leveling behavior without compromising sag resistance, may affect the uniformity of vehicle appearance. In addition to concerns about horizontal/vertical uniformity, the optimal balance of sag resistance and appearance is also beneficial for achieving good appearance in difficult shapes and contours that are prone to sag and drip during coating application.

It would be desirable to provide a curable film-forming composition that exhibits improved appearance properties over the entire substrate surface without loss of cured film properties, such as acid etch resistance and UV durability.

Disclosure of Invention

The present invention provides a curable film-forming composition comprising:

(a) a polymeric binder comprising epoxy functional groups;

(b) a curing agent comprising an acid functional group that reacts with the epoxy functional group of (a);

(c) a non-aqueous dispersion comprising the dispersion polymerization reaction product of a reaction mixture comprising ethylenically unsaturated monomers and ethylenically unsaturated nonlinear random acrylic polymer stabilizer, wherein the dispersion polymerization reaction product in the non-aqueous dispersion is present in the curable film-forming composition in an amount of from 0.5 to 10 weight percent based on the total weight of resin solids in the curable film-forming composition, and wherein the dispersion polymerization reaction product is different from the polymeric binder (a); and

(d) fumed silica present in the curable film-forming composition in an amount of 0.5 to 5 weight percent based on the total weight of resin solids in the curable film-forming composition.

Also provided are multilayer coated articles comprising the curable film-forming composition described above.

Detailed Description

Except in the operating examples, or where otherwise explicitly indicated, all numerical ranges, amounts, values and percentages, for example amounts of materials, times and temperatures of reaction, proportions of amounts, molecular weight (whether number average molecular weight ("M")), etc_n") or a weight average molecular weight (" M_w") and others in the following portions of this specification, may be considered to begin with the word" about, "even though the term" about "may not expressly appear with the stated value, amount, or range. Accordingly, unless indicated to the contrary, the numerical parameters set forth in the following specification and attached claims are approximations that may vary depending upon the desired properties sought to be obtained by the present invention. At the very least, and not as an attempt to limit the application of the doctrine of equivalents to the claimsTo the extent that each numerical parameter is at least construed in light of the number of reported significant digits and by applying ordinary rounding techniques.

Notwithstanding that the numerical ranges and parameters setting forth the broad scope of the invention are approximations, the numerical values set forth in the specific examples are reported as precisely as possible. Any numerical value, however, inherently contains certain errors necessarily resulting from the standard deviation found in their respective testing measurements. Further, when numerical ranges of varying ranges are set forth herein, it is contemplated that any combination of these values, inclusive of the recited values, may be used.

Plural referents used herein cover the singular and vice versa. For example, although the invention has been described in terms of "an" acrylic resin having epoxy functionality, a plurality of mixtures comprising such resins may be used.

Any numerical indication of an amount is "by weight" unless otherwise specified. The term "equivalent weight" is a calculated value based on the relative amounts of the various ingredients used to make a particular material, and is based on the solids of the particular material. Relative amounts are those yielding a theoretical weight in grams of material, e.g., polymer, produced from the ingredients and giving the theoretical number of specific functional groups present in the resulting polymer. The equivalent weight is obtained by dividing the theoretical polymer weight by the theoretical number of equivalents of functional group. For example, the urethane equivalents are based on the equivalents of urethane groups in the polyurethane material.

The curable film-forming compositions of the present invention are typically solvent-based. As used herein, the terms "thermoset" and "curable" are used interchangeably and refer to a resin that "sets" irreversibly when cured or crosslinked, wherein the polymer chains of the polymeric components are linked together by covalent bonds. This property is generally associated with a crosslinking reaction of the composition ingredients, which reaction is typically caused by, for example, heat or radiation. See, Hawley, Gessner G., (The Condensed Chemical Dictionary), ninth edition, page 856; in Surface Coatings (Surface Coatings), Vol.2, the Association of the Australian Oil and color Chemists' Association, Australia, the TAFE educational book (1974). Once cured or crosslinked, thermosetting resins do not melt upon heating and are insoluble in solvents. Further, as used herein, the terms "film-forming" and "coating" may be used interchangeably.

The curable film-forming composition of the present invention comprises (a) a polymeric binder comprising reactive epoxy functional groups. The polymeric binder is a film-forming binder and may be selected from one or more of the following: acrylic polymers, polyesters, polyurethanes, polyamides, polyethers, polythioethers, polythioesters, polyenes, and epoxy resins. Typically, the polymeric binder (a) comprises an acrylic and/or polyester polymer. It is noted that the phrase "and/or" when used in a list is intended to encompass alternative embodiments, including each individual component in the list as well as any combination of components. For example, the list "A, B and/or C" is intended to cover seven separate embodiments that include a, or B, or C, or a + B, or a + C, or B + C, or a + B + C. In general, these polymeric binders can be made by any suitable polymerization method known to those skilled in the art. The epoxy functionality on the film-forming binder reacts with the acid functionality on the curing agent (b).

Suitable acrylic polymers comprise copolymers of one or more alkyl esters of acrylic or methacrylic acid, optionally together with one or more other polymerizable ethylenically unsaturated monomers. Useful alkyl esters of acrylic or methacrylic acid comprise aliphatic alkyl esters containing from 1 to 30, typically from 4 to 18, carbon atoms in the alkyl group. Non-limiting examples include methyl methacrylate, ethyl methacrylate, butyl methacrylate, ethyl acrylate, butyl acrylate, and 2-ethylhexyl acrylate. Suitable other copolymerizable ethylenically unsaturated monomers include vinyl aromatic compounds such as styrene and vinyl toluene; nitriles such as acrylonitrile, methacrylonitrile; vinyl and vinylidene halides, such as vinyl chloride and vinylidene fluoride; and vinyl esters, such as vinyl acetate.

The acrylic copolymer may contain hydroxyl functionality that is typically incorporated into the polymer by including one or more hydroxyl functional monomers in the reactants used to produce the copolymer. Useful hydroxy-functional monomers include hydroxyalkyl acrylates and methacrylates, which typically have 2 to 4 carbon atoms in the hydroxyalkyl group, such as hydroxyethyl acrylate, hydroxypropyl acrylate, 4-hydroxybutyl acrylate, hydroxy-functional adducts of caprolactone and hydroxyalkyl acrylate, and the corresponding methacrylates and beta-hydroxy ester-functional monomers described below.

The beta-hydroxy ester functional monomer may be prepared from an ethylenically unsaturated epoxy functional monomer and a carboxylic acid having from about 13 to about 20 carbon atoms, or from an ethylenically unsaturated acid functional monomer and an epoxy compound containing at least 5 carbon atoms but no ethylenic unsaturation.

Useful ethylenically unsaturated epoxy-functional monomers for preparing the beta-hydroxy ester-functional monomer include glycidyl acrylate, glycidyl methacrylate, allyl glycidyl ether, methallyl glycidyl ether, 1:1 (mole) adducts of ethylenically unsaturated monoisocyanates with hydroxy-functional monoepoxides such as glycidol, and glycidyl esters of polymerizable polycarboxylic acids such as maleic acid. (Note: these epoxy functional monomers can also be used to provide epoxy functionality to the acrylic polymer.) examples of carboxylic acids include saturated monocarboxylic acids, such as isostearic acid, and aromatic unsaturated carboxylic acids.

Useful ethylenically unsaturated acid-functional monomers for preparing the β -hydroxy ester-functional monomer include monocarboxylic acids such as acrylic acid, methacrylic acid, crotonic acid; dicarboxylic acids such as itaconic acid, maleic acid and fumaric acid; and monoesters of dicarboxylic acids, such as monobutyl maleate and monobutyl itaconate. The ethylenically unsaturated acid-functional monomer and epoxy compound are typically reacted in an equivalent ratio of 1:1 (i.e., the ratio of equivalents of acid functional groups to equivalents of epoxy functional groups). The epoxy compound is free of ethylenically unsaturated bonds that would participate in free radical initiated polymerization with the unsaturated acid functional monomer. Useful epoxy compounds include 1, 2-epoxypentane, styrene oxide and glycidyl esters or ethers, typically containing from 6 to 30 carbon atoms, such as butyl glycidyl ether, octyl glycidyl ether, phenyl glycidyl ether and p- (tert-butyl) phenyl glycidyl ether. Specific glycidyl esters include those having the following structure:

wherein R is a hydrocarbon radical containing from about 4 to about 26 carbon atoms. Typically, R is a branched hydrocarbon group having from about 5 to about 10 carbon atoms, such as pivalate, neoheptanoate, or neodecanoate. Suitable glycidyl esters of carboxylic acids include glycidyl esters of CARDURA E and VERSATIC ACID 911, each of which is commercially available from Shell Chemical Co.

The acrylic polymer may be prepared via organic solution polymerization techniques for solvent borne compositions. Generally, any method known to those skilled in the art for producing such polymers using art-recognized amounts of monomers can be used.

In addition to the acrylic polymer, the polymeric binder (a) in the curable film-forming composition may be an alkyd or a polyester. Such polymers may be prepared in a known manner by condensation of a polyol and a polycarboxylic acid. Suitable polyols include, but are not limited to, ethylene glycol, propylene glycol, butylene glycol, 1, 6-hexanediol, neopentyl glycol, diethylene glycol, glycerol, trimethylolpropane, and pentaerythritol. Suitable polycarboxylic acids include, but are not limited to, succinic acid, adipic acid, azelaic acid, sebacic acid, maleic acid, fumaric acid, phthalic acid, tetrahydrophthalic acid, hexahydrophthalic acid, and trimellitic acid. In addition to the polycarboxylic acids described above, functional equivalents of the acids, such as anhydrides in which they are present; or lower alkyl esters of acids, such as methyl esters. When it is desired to produce an air drying alkyd resin, suitable drying oil fatty acids may be used, including, for example, those derived from linseed oil, soybean oil, tall oil, dehydrated castor oil, or tung oil.

Also, polyamides can be prepared using polyacids and polyamines. Suitable polyacids include those listed above, and the polyamine may be selected from at least one of the following: ethylenediamine, 1, 2-diaminopropane, 1, 4-diaminobutane, 1, 3-diaminopentane, 1, 6-diaminohexane, 2-methyl-1, 5-pentanediamine, 2, 5-diamino-2, 5-dimethylhexane, 2, 4-and/or 2,4, 4-trimethyl-1, 6-diamino-hexane, 1, 11-diaminoundecane, 1, 12-diaminododecane, 1, 3-and/or 1, 4-cyclohexanediamine, 1-amino-3, 3, 5-trimethyl-5-aminomethyl-cyclohexane, 2, 4-and/or 2, 6-hexahydrotoluenediamine, 2,4' -and/or 4,4' -diamino-dicyclohexylmethane and 3,3' -dialkyl-4, 4' -diamino-dicyclohexylmethane (e.g. 3,3' -dimethyl-4, 4' -diamino-dicyclohexylmethane and 3,3' -diethyl-4, 4' -diamino-dicyclohexylmethane), 2, 4-and/or 2, 6-diaminotoluene and 2,4' -and/or 4,4' -diaminodiphenylmethane.

Polyurethanes can also be used as polymeric binder (a) in curable film-forming compositions. Polyurethanes that can be used include polymeric polyols, which are generally prepared by: polyester polyols or acrylic polyols such as those described above are reacted with polyisocyanates such that the OH/NCO equivalent ratio is greater than 1:1, thereby leaving free hydroxyl groups present in the product. The organic polyisocyanate used to prepare the polyurethane polyol may be an aliphatic or aromatic polyisocyanate or a mixture of both. Diisocyanates are generally used, but higher polyisocyanates can also be used instead of or in combination with diisocyanates. Examples of suitable aromatic diisocyanates are 4,4' -diphenylmethane diisocyanate and toluene diisocyanate. Examples of suitable aliphatic diisocyanates are straight-chain aliphatic diisocyanates, such as 1, 6-hexamethylene diisocyanate. In addition, cycloaliphatic diisocyanates may be used. Examples include isophorone diisocyanate and 4,4' -methylene-bis- (cyclohexyl isocyanate). Examples of suitable higher polyisocyanates are 1,2, 4-benzene triisocyanate polymethylene polyphenyl isocyanates and isocyanate trimers based on 1, 6-hexamethylene diisocyanate or isophorone diisocyanate.

Examples of polyether polymers are polyalkylene ether polyols, including those having the following structural formula:

(i)

or (ii)

Wherein the substituent R₁Is hydrogen or lower alkyl of 1 to 5 carbon atoms, including mixed substituents, and n is typically 2 to 6 and m is 8 to 100 or higher. Comprising poly (tetramethylene) glycol, poly (tetraethylene) glycol, poly (1, 2-propylene) glycol, and poly (1, 2-butylene) glycol.

Also useful are polyether polymers formed by the alkoxylation of various polyols, such as glycols, e.g., ethylene glycol, 1, 6-hexanediol, bisphenol a, and the like, or other higher polyols; such as trimethylolpropane, pentaerythritol, and the like. Polyols with higher functionality that can be used as indicated can be made, for example, by alkoxylation of compounds such as sucrose or sorbitol. One commonly used alkoxylation process is to react a polyol with an alkylene oxide, such as propylene oxide or ethylene oxide, in the presence of an acidic or basic catalyst.

As discussed above, the epoxy-functional film-forming polymer can be an acrylic polymer prepared with epoxy-functional monomers such as glycidyl acrylate, glycidyl methacrylate, allyl glycidyl ether, and methallyl glycidyl ether. Polyesters, polyethers, polyurethanes or polyamides prepared with glycidyl alcohols or glycidyl amines or reacted with epihalohydrins are also suitable epoxy-functional resins. Epoxide functional groups can be incorporated into the resin by reacting hydroxyl groups on the resin with an epihalohydrin or dihalohydrin, such as epichlorohydrin or dichlorohydrin, in the presence of a base.

Other suitable epoxy-functional polymers for use as the polymeric binder (a) may comprise chain-extended polyepoxides by reacting together a polyepoxide with a polyhydroxy group containing material selected from alcoholic hydroxyl group containing materials and phenolic hydroxyl group containing materials to chain-extend or increase the molecular weight of the polyepoxide.

Chain-extended polyepoxides are generally prepared by: reacting together a polyepoxide and a polyhydroxy group containing material under solventless conditions or in the presence of an inert organic solvent, such as a ketone, including methyl isobutyl ketone and methyl amyl ketone; aromatic compounds such as toluene and xylene; and glycol ethers such as dimethyl ether of diethylene glycol. The reaction is typically carried out at a temperature of about 80 ℃ to 160 ℃ for about 30 to 180 minutes until an epoxy group-containing resin reaction product is obtained.

The equivalent ratio of reactants (i.e., epoxy-containing material: polyhydroxy-containing material) is typically about 1.00:0.75 to 1.00: 2.00.

By definition, polyepoxides have at least two 1, 2-epoxy groups. Typically, the polyepoxide has an epoxide equivalent weight in the range of from 100 to about 2000, typically from about 180 to 500. The epoxy compound may be saturated or unsaturated, cyclic or acyclic, aliphatic, alicyclic, aromatic or heterocyclic. They may contain substituents such as halogen, hydroxyl and ether groups.

The most commonly used polyepoxides are the polyglycidyl ethers of cyclic polyols, for example the polyglycidyl ethers of polyhydric phenols such as bisphenol A, resorcinol, hydroquinone, benzenedimethanol, phloroglucinol, catechol, and the like; or polyglycidyl ethers of polyhydric alcohols such as alicyclic polyhydric alcohols, particularly alicyclic polyhydric alcohols such as 1, 2-cyclohexanediol, 1, 4-cyclohexanediol, 2-bis (4-hydroxycyclohexyl) propane, 1-bis (4-hydroxycyclohexyl) ethane, 2-methyl-1, 1-bis (4-hydroxycyclohexyl) propane, 2-bis (4-hydroxy-3-tert-butylcyclohexyl) propane, 1, 3-bis (hydroxymethyl) cyclohexane and 1, 2-bis (hydroxymethyl) cyclohexane. Examples of aliphatic polyols include, inter alia, trimethylpentanediol and neopentyl glycol.

The polyol-containing material used to chain extend or increase the molecular weight of the polyepoxide may also be a polymeric polyol, such as any of those disclosed above. The present invention may include epoxy resins such as diglycidyl ethers of bisphenol a, bisphenol F, glycerol, phenolic resins, and the like. Exemplary suitable polyepoxides are described in U.S. patent No. 4,681,811, column 5, lines 33 to 58, the referenced portions of which are incorporated herein by reference.

The amount of polymeric binder (a) in the curable film-forming composition is typically in the range of from 5 to 50% by weight based on the total weight of resin solids in the curable film-forming composition. The minimum amount of polymeric binder may be at least 5 wt%, usually at least 10 wt%, more usually at least 25 wt%. The maximum amount of polymeric binder may be 50 wt%, more often 35 wt% or 30 wt%. For example, the amount of polymeric binder (a) in the curable film-forming composition may range from 5 to 50 wt.%, or 5 to 35 wt.%, or 5 to 30 wt.%, or 10 to 50 wt.%, or 10 to 35 wt.%, or 10 to 30 wt.%, or 25 to 50 wt.%, or 25 to 35 wt.%, or 25 to 30 wt.%, based on the total weight of resin solids in the curable film-forming composition.

Suitable curing agents (b) for use in the curable film-forming composition of the present invention include acid functional groups and/or anhydride functional groups that react with the epoxy functional groups in the polymeric binder (a). Examples of suitable polycarboxylic acids include adipic acid, succinic acid, sebacic acid, azelaic acid and dodecanedioic acid. Other suitable polyacid crosslinking agents include acid group-containing acrylic polymers prepared from ethylenically unsaturated monomers containing at least one carboxylic acid group and at least one ethylenically unsaturated monomer free of carboxylic acid groups. Such acid functional acrylic polymers may have an acid value of 30 to 150. Acid functional group-containing polyesters may also be used. Low molecular weight polyesters and half-acid esters based on the condensation of aliphatic polyols with aliphatic and/or aromatic polycarboxylic acids or anhydrides may be used. Examples of suitable aliphatic polyols include ethylene glycol, propylene glycol, butylene glycol, 1, 6-hexanediol, trimethylolpropane, ditrimethylolpropane, neopentyl glycol, 1, 4-cyclohexanedimethanol, pentaerythritol and the like. The polycarboxylic acids and anhydrides may include, inter alia, terephthalic acid, isophthalic acid, phthalic anhydride, tetrahydrophthalic acid, tetrahydrophthalic anhydride, hexahydrophthalic anhydride, methylhexahydrophthalic anhydride, chlorendic anhydride, and the like. Mixtures of acids and/or anhydrides may also be used. The polyacid crosslinking agents described above are further detailed in U.S. patent No. 4,681,811, column 6, line 45 to column 9, line 54, which is incorporated herein by reference.

Mixtures of suitable crosslinking agents may also be used in the present invention. For example, two or more different acid functional acrylic polymers, two or more different acid functional polyester polymers, or a mixture of two or more different acid functional acrylic polymers and acid functional polyester polymers may be used as the curing agent (b). The curable film-forming composition of the present invention may further comprise one or more additional crosslinkers other than the acid-functional curing agent (b). Examples include aminoplasts and polyisocyanates. Useful aminoplasts can be obtained from the condensation reaction of formaldehyde with amines or amides. Non-limiting examples of amines or amides include melamine, urea, and benzoguanamine.

While condensation products obtained from the reaction of alcohols and formaldehyde with melamine, urea or benzoguanamine are the most common, condensates with other amines or amides may also be used. Formaldehyde is the most commonly used aldehyde, but other aldehydes, such as acetaldehyde, crotonaldehyde, and benzaldehyde, can also be used.

The aminoplast may contain imino and hydroxymethyl groups. In certain examples, at least a portion of the hydroxymethyl groups may be etherified with an alcohol to modify the curing reaction. For the present purpose, any monohydric alcohol may be used, such as methanol, ethanol, n-butanol, isobutanol and hexanol. Non-limiting examples of suitable aminoplast resins are commercially available from Cytec Industries, Inc. (trade marks)) And Intels (trade mark))。

Other suitable crosslinking agents include polyisocyanate crosslinking agents. As used herein, the term "polyisocyanate" is intended to encompass blocked polyisocyanates as well as unblocked polyisocyanates. The polyisocyanate may be aliphatic, aromatic or a mixture thereof. Although higher polyisocyanates such as isocyanurates of diisocyanates are generally used, diisocyanates may also be used. Isocyanate prepolymers, such as the reaction product of a polyisocyanate and a polyol, may also be used. Mixtures of polyisocyanate crosslinkers can be used.

Polyisocyanates can be prepared from a variety of isocyanate-containing materials. Examples of suitable polyisocyanates include trimers prepared from the following diisocyanates: toluene diisocyanate, 4,4 '-methylene-bis (cyclohexyl isocyanate), isophorone diisocyanate, isomeric mixtures of 2,2, 4-and 2,4, 4-trimethylhexamethylene diisocyanate, 1, 6-hexamethylene diisocyanate, tetramethylxylylene diisocyanate and 4,4' -diphenylmethylene diisocyanate. In addition, blocked polyisocyanate prepolymers of various polyols, such as polyester polyols, may also be used.

The isocyanate groups may be blocked or unblocked as desired. If a polyisocyanate is to be blocked, any suitable aliphatic, cycloaliphatic or aromatic alkyl monoalcohol or phenol compound known to those skilled in the art may be used as the blocking agent for the polyisocyanate. Examples of suitable blocking agents include those materials that are not capped at elevated temperatures, such as lower aliphatic alcohols, including methanol, ethanol, and n-butanol; alicyclic alcohols such as cyclohexanol; aromatic alkyl alcohols such as phenyl carbinol, methyl phenyl carbinol; phenolic compounds, such as phenol itself and substituted phenols, in which the substituents do not interfere with the coating operation, such as cresols and nitrophenols. Glycol ethers may also be used as end-capping agents. Suitable glycol ethers include ethylene glycol butyl ether, diethylene glycol butyl ether, ethylene glycol methyl ether, and propylene glycol methyl ether. Other suitable blocking agents include oximes such as methyl ethyl ketoxime, acetone oxime, and cyclohexanone oxime; lactams, such as epsilon-caprolactam; pyrazoles such as dimethylpyrazole; and amines, such as dibutylamine.

The amount of curing agent in the curable film-forming composition is typically in the range of from 5 to 75 weight percent, based on the total weight of resin solids in the curable film-forming composition. For example, the minimum amount of curing agent can be at least 5 weight percent, often at least 10 weight percent, and more often at least 15 weight percent. The maximum amount of curing agent may be 75 wt%, more often 60 wt% or 55 wt%. Ranges of curing agents may include, for example, 5 to 50 weight percent, 5 to 60 weight percent, 10 to 50 weight percent, 10 to 60 weight percent, 10 to 75 weight percent, 15 to 50 weight percent, 15-60 weight percent, and 15-75 weight percent.

The curable film-forming composition of the present invention additionally comprises (c) a non-aqueous dispersion comprising the dispersion polymerization product of ethylenically unsaturated monomers and a nonlinear random acrylic polymer stabilizer. The dispersion polymerization reaction product is different from the polymeric binder (a). As used herein, the term "nonlinear" refers to the presence of at least one branch point along and extending from a polymer backbone. As used herein, "branching" is defined in outline of Polymer Nomenclature and Nomenclature, IUPAC recommendation 2008(Compendium of Polymer technology and Nomenclature, IUPAC Recommendations2008), published by Royal chemical society of England (RSC Publishing), ISBN: 978-0-85404-491-7. The branches are typically polymeric and derived from ethylenically unsaturated monomers, such as (meth) acrylic monomers. In some cases, there may be multiple branch points (i.e., "hyperbranched"), and in some instances, the branches may form links between polymer chains (i.e., internal crosslinking). Polymer branching can be quantified using the Mark-Howink parameter. In certain examples, the nonlinear acrylic polymeric stabilizers of the present invention have a Mark-Howink parameter of from 0.2 to 0.7, such as from 0.3 to 0.6, as measured by three detector GPC.

Nonlinear stabilizers are "random" or predominantly homogeneous. That is, the polymer is substantially free of blocks or segments that are compositionally different from the remainder of the polymer. For example, in a typical "comb" polymer, the backbone of the polymer has one composition, while the "teeth" of the comb have another composition. This is not the case for random or homogeneous polymers in which the monomers are free to react and do not react in a predetermined pattern or sequence. Thus, the monomers are randomly assembled in the final polymer.

The term "acrylic polymer stabilizer" as used in the context of the present invention refers to a polymer comprising 50 or more weight% of residues derived from (meth) acrylic monomers, based on the total weight of the polymer. As used herein and as is conventional in the art, (meth) used in conjunction with another word such as acrylate refers to both acrylate and the corresponding methacrylate. In certain examples, the non-linear acrylic polymeric stabilizer is prepared from a reaction mixture comprising 75 or greater weight percent, such as 90 or greater weight percent or 95 or greater weight percent of (meth) acrylic monomer. In certain examples, the stabilizer is prepared from a reaction mixture that includes 100 wt% of a (meth) acrylic monomer. The term "(meth) acrylic monomer" does not encompass polymeric species, such as macromonomers. The stabilizer may be prepared from a polar (meth) acrylic monomer, such as a hydroxy-functional (meth) acrylic monomer, in an amount of 30 or less weight percent, such as 20 or less weight percent, 15 or less weight percent, or 10 or less weight percent. In other examples, the stabilizer may be prepared from a non-polar (meth) acrylic monomer, such as 2-ethylhexyl acrylate, in an amount of 50 or greater weight percent, such as 60 or greater weight percent, 70 or greater weight percent, or 80 or greater weight percent. The wt% used in the context of wt% of monomer refers to the wt% of monomer used to form the stabilizer and does not contain other ingredients, such as initiators, chain transfer agents, additives, etc. used to form the stabilizer. "acrylic" monomers generally refer to acrylic, methacrylic, and any derivative of any of these.

The non-linear acrylic polymer stabilizer may be prepared by: reacting two or more coreactive monomers, such as glycidyl (meth) acrylate and (meth) acrylic acid; or preparing an acrylic polymer having functional groups and crosslinking the functional groups, for example by making a hydroxy-functional polymer and reacting it with a diisocyanate or epoxy-functional polymer and reacting it with a dibasic acid. In one particularly suitable example, the non-linear acrylic polymer stabilizer may be prepared from a reaction mixture comprising one or more multifunctional ethylenically unsaturated monomers. Suitable polyfunctional ethylenically unsaturated monomers include allyl (meth) acrylate, alkanediol di (meth) acrylates, such as 1, 6-hexanediol diacrylate or ethylene glycol dimethacrylate, trimethylolpropane triacrylate, and divinylbenzene.

The use of multifunctional ethylenically unsaturated monomers in the formation of the acrylic polymer stabilizer achieves polymerization non-linearity of the polymer. Typically, the polyfunctional monomer will be used in an amount of from 0.1 to 10 weight percent, for example from 0.25 to 5 or from 0.5 to 2 weight percent, based on the total weight of monomers used to prepare the stabilizer. If the amount of the polyfunctional monomer used is too high, gelation may occur. The level of multifunctional monomer can be selected to produce a desired amount of non-linearity or branching without gelling the product. One or more multifunctional ethylenically unsaturated monomers may be used. In some examples, two (or more) ethylenically unsaturated functional groups within the same monomer molecule may have different reactivities with respect to other (meth) acrylate monomers used to form the stabilizer. Each polyfunctional ethylenically unsaturated monomer molecule may be fully reacted with the other (meth) acrylate monomer to form a polymeric branch or crosslink, or it may be incompletely reacted and retain at least one of its ethylenically unsaturated functional groups. The resulting nonlinear acrylic polymer stabilizer will have ethylenic unsaturation, which may be due to unreacted ethylenic unsaturation on the polyfunctional monomer, or it may be added to the acrylic polymer stabilizer by post-reacting the pendant functional groups on the polymer stabilizer with an ethylenically unsaturated monomer having additional functional groups that react with the pendant groups on the polymer stabilizer. For example, pendant acid functional groups on an acrylic polymer stabilizer can be post-reacted with an epoxy functional monomer such as glycidyl methacrylate to produce free ethylenically unsaturated groups. Such unsaturated bonds may then be used to react during preparation of the non-aqueous dispersion, thereby covalently bonding the non-linear acrylic polymeric stabilizer to the ethylenically unsaturated core monomer during polymerization of the core monomer to form the non-aqueous dispersion, as described further below.

In the formation of the non-linear acrylic polymer stabilizer, the multifunctional monomer will be polymerized with one or more additional ethylenically unsaturated monomers and an initiator such as a free radical initiator. Suitable monomers include methyl (meth) acrylate, ethyl (meth) acrylate, n-butyl (meth) acrylate, isobutyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, isobornyl (meth) acrylate, 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, meth) acrylic acid, glycidyl (meth) acrylate, styrene, alpha-methylstyrene, lauryl (meth) acrylate, stearyl (meth) acrylate, itaconic acid and esters thereof, and the like. As noted above, 50 or more weight percent of the monomers used to form the stabilizer are acrylic. Suitable free radical initiators include peroxy initiators such as benzoyl peroxide, lauroyl peroxide, or t-butyl peroxy-2-ethyl-hexanoate (t-butyl peroxyoctoate); and azo initiators, such as 2,2 '-azobis (2, 4-dimethylvaleronitrile) or 2,2' -azobis (2-methylbutyronitrile).

Typically, the non-linear acrylic polymeric stabilizer is formed by solution polymerization of ethylenically unsaturated monomers (at least one of which is multifunctional) by standard free radical polymerization methods known to those skilled in the art. For example, the ethylenically unsaturated monomer can be added to a suitable solvent at an elevated temperature (e.g., the reflux temperature of the solvent) over a period of time. A free radical initiator, such as a peroxide initiator, is added to the reaction mixture over about the same period of time. The initiator is selected such that it initiates free radical polymerization of the monomers at the selected reaction temperature. After the monomers and initiator are added to the reaction mixture, the mixture may be held at the reaction temperature for an extended period of time during which additional initiator may be added to ensure complete conversion of the monomers. The progress of the reaction can be monitored by solid measurement or gas chromatography.

The stabilizer may be prepared in a continuous reactor. For example, the (meth) acrylate monomer and a free radical initiator such as a peroxide initiator may be fed continuously through the continuous reactor at 150 ℃ and 260 ℃ with a residence time of 1 to 20 minutes. The (meth) acrylate monomers used herein may be polar, non-polar or a mixture of the two types.

The molar ratio of acrylate to methacrylate may be about 2:1. For example, initiator levels can range from 0.5 to 2.0%, such as 1.0 to 1.5%, based on the total weight of the monomers.

The weight average molecular weight of the stabilizer, as measured by gel permeation chromatography relative to a linear polystyrene standard, can be 10,000 to 1,000,000, e.g., 20,000 to 80,000 or 30,000 to 60,000. The stabilizer comprising an ethylenically unsaturated bond, e.g. by¹³And C NMR spectroscopy detection. The stabilizer may contain further functional groups, for example hydroxyl groups, carboxylic acid groups and/or epoxy groups.

In certain embodiments, the acrylic polymeric stabilizer has a Vanccrifleron solubility parameter at 298K of 17 to 28MPa^0.5E.g. 17.5 to 20MPa^0.5Or 18 to 19MPa^0.5. In the case of copolymers, the solubility parameter can be calculated from the weighted average of the van crifferson solubility parameters derived from the homopolymers of the individual monomers. The Vancrelive solubility parameter of the homopolymer was calculated using Synthia as implemented in Material Studio 5.0 (available from Accelrys, Inc. of san Diego, Calif.).

The stabilizer is further reacted with a monomer or monomer mixture having an ethylenically unsaturated bond. These monomers are sometimes referred to herein as "core monomers" to distinguish them from the monomers used to prepare the stabilizer. The core monomer and stabilizer are reacted via the ethylenically unsaturated bond by dispersion polymerization techniques known to those skilled in the art. For example, the stabilizer may be dissolved in a suitable solvent or solvent mixture, and the monomer may be added to the solution at an elevated temperature over a period of time during which the free radical initiator is also added to the mixture. The monomers may be added in a single timed feed, or they may be added in stages, for example in two stages. When added simultaneously or at different times, the monomers may be of the same or different composition.

Suitable core monomers include methyl (meth) acrylate, ethyl (meth) acrylate, n-butyl (meth) acrylate, isobutyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, isobornyl (meth) acrylate, 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, meth) acrylic acid, glycidyl (meth) acrylate, styrene, alpha-methylstyrene, lauryl (meth) acrylate, stearyl (meth) acrylate, itaconic acid and esters thereof, and the like. In certain examples, the monomers include multifunctional ethylenically unsaturated monomers including allyl (meth) acrylate, alkylene glycol di (meth) acrylates such as 1, 6-hexanediol diacrylate and ethylene glycol dimethacrylate; trimethylolpropane triacrylate, divinylbenzene or other suitable poly (meth) acrylates.

The solubility parameter of the solvent may be selected from the group consisting of "hansen solubility parameter: user manual (Handsen solubility parameters: a user's handbook) ", Charles M.Hansen, CRC Press, Inc., of Pokaraton, Florida, 2007. The solubility parameter of the solvent mixture may be calculated from a weighted average of the solubility parameters of the various solvents. Acrylic polymeric stabilizers are generally compatible with the continuous phase of the non-aqueous dispersion. By "compatible" is meant, for example, that the solubility parameter of the solvent is generally lower than the solubility parameter of the stabilizer, for example by 3 units or less or by 2.5 units or less; if the difference is more than 3 units, the stabilizer may not be soluble in the solvent. As used in reference to solubility parameters, "unit" refers to MPa^0.5。

It is understood that the "dispersion polymerization product" used interchangeably with "polymerization product" is the product resulting from the reaction of the ethylenically unsaturated monomer component (i.e., the core monomer) and the acrylic polymer stabilizer. The polymerization reaction product may include functional groups, such as epoxy and/or hydroxyl functional groups.

The polymerization reaction product may contain epoxy functionality as described above. In certain examples, the epoxy equivalent weight of the polymerization reaction product may be from 100 to 5000, such as from 200 to 2000. The epoxy functionality may be introduced, for example, by using an ethylenically unsaturated epoxy functional monomer such as glycidyl (meth) acrylate as a core monomer. Alternatively, the epoxy functional group may be introduced by using an ethylenically unsaturated epoxy functional monomer in the acrylic polymer stabilizer. In certain examples, epoxy functionality may be introduced by using an ethylenically unsaturated epoxy functional monomer in the acrylic polymer stabilizer and as a core monomer. In certain other examples, the epoxy functionality may be introduced by post-modifying the polymerization product after formation of the non-aqueous dispersion. For example, the polymerization reaction product of the non-aqueous dispersion may be hydroxyl functional and it may be reacted with a compound containing both a functional group that reacts with a hydroxyl group and an unreacted epoxy group. In any of these embodiments, the final polymerization reaction product will be epoxy-functional.

In certain examples, the polymerization reaction product of the non-aqueous dispersion may include more than one type of functional group. For example, the polymerization reaction product may include both epoxy and hydroxyl functional groups. The functional groups can be introduced by using any of the methods described above for introducing epoxy functional groups. In certain embodiments, the theoretical hydroxyl number may be 30 to 300, such as 40 to 280 or 50 to 230. The polymerization reaction product of the non-aqueous dispersion may further comprise acid functionality. In certain embodiments, the theoretical acid number may be from 0 to 80, such as from 0 to 40 or from 5 to 20.

The reaction of the core monomer with the stabilizer may result in the formation of particles. The weight average molecular weight of the dispersion polymerization reaction product, as measured by gel permeation chromatography relative to linear polystyrene, can be very high, e.g., 100,000g/mol, or can be too high to measure due to gel formation within the particles. When used in coatings, particles having a high gel content contribute to one or more enhanced properties, such as improved appearance, resistance to solvents, acids, and the like, improved sag resistance, improved metal flake orientation, and/or improved resistance to interlayer mixing when multiple coatings are applied. In certain examples, the gel content of the dispersion as measured by the ultracentrifugation method is 30 or greater weight percent, such as 40 or greater weight percent, where weight percent is based on total solid weight. In the ultracentrifugation method on which these values are based, 2 g of the dispersion is added to a centrifuge tube, which is then filled with 10 g of a solvent such as Tetrahydrofuran (THF), and the materials are mixed thoroughly. The prepared tubes were placed in an ultracentrifuge at a speed of 50,000rpm or greater for 30 minutes or more. The undissolved portion of the dispersion was separated and dried to constant weight at 110 ℃ to provide the gel content of the dispersion.

The dispersion polymerization reaction product in the non-aqueous dispersion used in the curable film-forming composition of the present invention may be internally crosslinked or uncrosslinked. In some cases, a crosslinked dispersion polymerization reaction product may be more desirable than an uncrosslinked dispersion polymerization reaction product because the uncrosslinked material is more likely to swell or dissolve in the organic solvent used in the coating composition. The crosslinked dispersion polymerization reaction product may have a significantly higher molecular weight than the uncrosslinked dispersion. Crosslinking of the dispersion polymerization reaction product may be achieved, for example, by including a multifunctional ethylenically unsaturated monomer (or crosslinker) and an ethylenically unsaturated core monomer or monomer mixture during polymerization. The polyfunctional ethylenically unsaturated monomer may be present in an amount of from 0 to 20 weight percent, for example from 1 to 10 weight percent, based on the total weight of the core monomers used to prepare the dispersion polymerization reaction product.

In certain examples, the core monomer polymerized with the acrylic polymer stabilizer includes less than 90% by weight of polar and/or functional monomers. As used herein, the term "polar" means 19MPa at 298K^0.5Or a higher solubility parameter (van criffen). In contrast, the term "nonpolar" describes a polymer having a viscosity of less than 19MPa at 298K^0.5A solubility parameter of (van crifferon).

In certain embodiments of the present invention, the reaction mixture used to prepare the dispersion polymerization reaction product may further comprise an aliphatic polyester stabilized seed polymer. As used herein, the term "aliphatic polyester" refers to a polyester that is soluble in an aliphatic hydrocarbon solvent such as heptane. The carbon/oxygen ratio of the polyester can be used to predict this solubility. The ratio can be calculated from the molar ratio of the monomers minus the water of esterification. For example, if the carbon/oxygen ratio of the polyester is from 4:1 to 20:1, such as from 6:1 to 12:1, the polyester will be soluble in a hydrocarbon solvent such as heptane, or in a slightly more polar solvent system, such as 60% ISOPAR K and 40% butyl acetate. ISOPAR K is a hydrocarbon solvent commercially available from Exxon-Mobile Company. For example, a suitable polyester would be poly-12-hydroxystearic acid having a carbon/oxygen ratio of 9: 1.

Aliphatic polyesters may be used to prepare stabilizers, sometimes referred to herein as "seed stage stabilizers," used to prepare the seed stage of the dispersion polymerization reaction product. The seed stage stabilizer may comprise two segments, one of which comprises the above-described aliphatic polyester, and the other of which has a different polarity than the polyester and is relatively insoluble in aliphatic hydrocarbon solvents. The first of these is sometimes referred to herein as the "aliphatic polyester component" and the second is referred to as the "stabilizer component". Suitable stabilizer components are known, and some examples have been described in U.S. patent No. 4,147,688, column 5, line 1-column 6, line 44, which is incorporated herein by reference.

The aliphatic polyester component may include poly-12-hydroxystearic acid having a number average molecular weight of about 300 to 3,000 and including acid and hydroxyl functional groups. Poly-12-hydroxystearic acid may then be reacted with a compound comprising a (meth) acrylate functional group and a second type of functional group that may react with the hydroxyl or acid functional group of poly-12-hydroxystearic acid. A suitable compound would be, for example, glycidyl (meth) acrylate. The reaction product of poly-12-hydroxystearic acid and glycidyl (meth) acrylate can be further reacted with an ethylenically unsaturated monomer of a different polarity than poly-12-hydroxystearic acid by standard free radical polymerization to provide the polyester stabilizer of the present invention. Suitable ethylenically unsaturated monomers include, but are not limited to, (meth) acrylic acid, methyl (meth) acrylate, ethyl (meth) acrylate, n-butyl (meth) acrylate, isobutyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, isobornyl (meth) acrylate, 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, (meth) acrylic acid, glycidyl (meth) acrylate, styrene, alpha-methylstyrene, lauryl (meth) acrylate, stearyl (meth) acrylate, itaconic acid and esters thereof, and the like. In one embodiment, the ethylenically unsaturated monomers include methyl methacrylate, glycidyl methacrylate, and methacrylic acid. It will be appreciated that standard free radical polymerization techniques are well known to those skilled in the art. The seed stage stabilizer may be 20 to 65 weight percent polyester, for example 25 to 60 weight percent, 30 to 55 weight percent, or 33 to 53 weight percent polyester, where weight percent is based on the total weight of the components of the seed stage stabilizer.

Seed stage stabilizers can be used to prepare seed polymers. As used herein, the term "seed polymer" refers to a dispersed polymer having a particle size of less than 80nm, for example less than 50 nm. Seed polymers generally include the seed stage stabilizers and dispersion polymers described above. The seed polymer may be prepared by dissolving the seed stage stabilizer in a suitable solvent or solvent mixture, and the monomers used to form the seed polymer ("seed monomers") may be added to the solution at elevated temperature over a period of time during which a free radical initiator may also be added to the mixture. The dispersion polymer may be covalently bonded or grafted to the seed stage stabilizer. The seed polymer may be prepared, for example, from a seed stage stabilizer and an ethylenically unsaturated monomer such as a (meth) acrylate monomer. The polymer formed from the ethylenically unsaturated monomer should be insoluble in the continuous phase so as to provide a stable dispersion, rather than a solution. It will be understood by those skilled in the art that if the seed stage stabiliser comprises ethylenically unsaturated bonds, then in addition to polymerisation of the seed monomer with other seed monomers, at least some of the polymerisable double bonds of the stabiliser will react with some of the seed monomers under these conditions. By this process, the seed polymer will graft, i.e. covalently bond, to the seed stage stabilizer. Suitable seed polymers may be prepared from seed stage stabilizers including 60% ISOPAR K and 40% butyl acetate and methyl methacrylate solution of poly-12-hydroxystearic acid.

The seed polymer as described above may be a stable dispersion. For example, seed polymers can be prepared and stored for later use. Alternatively, it can be used immediately to prepare the non-aqueous dispersion. When a seed polymer is used, the weight ratio of seed polymer to ethylenically unsaturated monomer (i.e., "core monomer") in the reaction mixture is from 1:100 to 20:100, such as from 5:100 to 15: 100. In some examples, the weight ratio of acrylic polymeric stabilizer to "core monomer" is from 10:100 to 100:10, such as from 20:100 to 100: 20.

When an aliphatic polyester-stabilized seed polymer is included in the reaction mixture, the non-aqueous dispersion (c) may be prepared, for example, as follows. The mixture of seed stage stabilizer and seed monomer, such as ethylenically unsaturated monomer, can be added to a hydrocarbon solvent, such as ISOPAR E (isoparaffinic solvent, available from ExxonMobil Chemical) at high temperature, such as 90 ℃, over a period of time (e.g., over 30 minutes). The ratio of seed stage stabilizer to seed monomer may be from 0.2:1.0 to 4.0:1.0, for example from 0.5:1.0 to 2.0: 1.0. A free radical initiator, such as azobis-2, 2' - (2-methylbutyronitrile), may be added to the reaction mixture over about the same period of time. The initiator is selected such that it initiates free radical polymerization of the seed monomer at the selected reaction temperature. The free radical initiator may constitute from 1% to 10%, for example from 4% to 8% by weight of the composition of the reactants. During the addition, the mixture may be stirred at a suitable speed, for example 200 to 300 rpm. After the addition of the seed stage stabilizer, seed monomer, and free radical initiator is complete, the resulting mixture may be about 2% to 12%, for example about 4% to 10% by weight solids. The mixture may be held at the same elevated temperature for an additional period of time, for example 30 minutes. The foregoing process produces an aliphatic polyester stabilized seed polymer. At this point, the mixture may be separated and stored for later use. Alternatively, the mixture may be used immediately.

The mixture of acrylic polymer stabilizer and ethylenically unsaturated monomer may be added to the mixture of aliphatic polyester stabilized seed polymers over a period of time (e.g., over 180 minutes) at an elevated temperature such as 90 ℃. In some embodiments, additional aliphatic polyester stabilized seed polymer may be added with the acrylic polymer stabilizer and ethylenically unsaturated monomer, for example, from 0.5% to 5.0% by weight or from 1.0% to 2.0% by weight, based on the total weight of monomers used to prepare the non-aqueous dispersion. Chain transfer agents, such as n-octyl mercaptan, may be added with the acrylic polymer stabilizer, ethylenically unsaturated monomer, and/or seed stage stabilized seed polymer in an amount of about 0.5 to 5.0 weight percent, such as 1.0 to 2.0 weight percent. The ethylenically unsaturated monomers are as described above. A free radical initiator, such as azobis-2, 2' - (2-methylbutyronitrile), may be added to the reaction mixture over about the same period of time. The initiator is selected such that it initiates free radical polymerization of the core monomer at the selected reaction temperature. The free radical initiator may constitute from 0.2% to 5.0%, for example from 0.5% to 2.0% by weight of the composition of the reactants. After the addition of the acrylic stabilizer, ethylenically unsaturated monomer, and free radical initiator is complete, the resulting mixture may be held at the reaction temperature for an extended period of time, for example 120 minutes, during which additional initiator may be added to ensure complete conversion of the monomers. The progress of the reaction can be monitored by solid measurement or gas chromatography. After the process is complete, the resulting non-aqueous dispersion of the present invention may be about 15% to 70%, for example 20% to 65%, 22% to 62%, or 32% to 52% by weight solids.

Any of the non-aqueous dispersions described herein further comprise a continuous phase, which is sometimes referred to as a dispersion medium or carrier. Any suitable carrier may be used, including esters, ketones, glycol ethers, alcohols, hydrocarbons, or mixtures thereof. Suitable ester solvents include alkyl acetates such as ethyl acetate, n-butyl acetate, n-hexyl acetate, and mixtures thereof. Examples of suitable ketone solvents include methyl ethyl ketone, methyl isobutyl ketone, and mixtures thereof. Examples of suitable hydrocarbon solvents include toluene, xylene, aromatic hydrocarbons such as those available under the SOLVESSO trade name from Exxon-Mobil Chemical Company, and aliphatic hydrocarbons such as hexane, heptane, nonane, and those available under the ISOPAR and VARSOL trade names from Exxon Mobil Chemical Company. In certain embodiments, the carrier is volatile. In certain other embodiments, the carrier is not an alkyd resin and/or any other fatty acid containing compound.

Those skilled in the art will appreciate that the non-aqueous dispersion used in the curable film-forming composition of the present invention is different from a latex that is an aqueous dispersion. The non-aqueous dispersion of the present invention is also different from the polymer solution in that the non-aqueous dispersion has a distinct dispersed phase different from the continuous phase, whereas the polymer solution has a single homogeneous phase. As used herein, a "non-aqueous dispersion" wherein 75% or more, such as 90% or more or 95% or more of the dispersion medium is a non-aqueous solvent, such as any of those listed above. Thus, the non-aqueous dispersion may still include some level of aqueous material, such as water.

The average particle diameter of the dispersion polymerization product in the non-aqueous dispersion is usually 1 μm or less, for example 500nm or less, for example 250nm or less, usually 200-250 nm. Particle size is measured by dynamic light scattering, for example using a Malvern Zetasizer, which is a high performance two-angle particle size analyzer used to enhance the detection of aggregates and the measurement of small or dilute samples as well as very low or high concentration samples using dynamic light scattering. A typical application of dynamic light scattering is the characterization of particles, emulsions or molecules dispersed or dissolved in a liquid. Brownian motion of suspended particles or molecules causes the laser light to scatter at different intensities. Analysis of these intensity fluctuations gives rise to the velocity of brownian motion and hence the particle size using the stokes-einstein relationship. The reported particle sizes for all examples are the Z-average.

Typically, the dispersion polymerization product of the non-aqueous dispersion (c) is present in the curable film-forming composition in an amount of at least 0.5% by weight or at least 1% by weight, based on the total weight of resin solids in the curable film-forming composition. Further, the dispersion polymerization product of the non-aqueous dispersion (c) may be present in the curable film-forming composition in an amount of up to 10 weight percent or up to 8 weight percent, based on the total weight of resin solids in the curable film-forming composition.

The curable film-forming composition of the present invention further comprises (d) fumed silica, typically in dispersion form. Fumed silica is made by flame pyrolysis of silicon tetrachloride or quartz sand and is evaporated in an electric arc at 3000 ℃. Any fumed silica known in the art as a suitable rheology control agent may be used. Manufacturers include the creative resources Efficiency company (Evonik Resource Efficiency GmbH) (sold under the name Aerosil), Cabot Corporation (Cabot Corporation) (Cab-O-Sil), Wacker chemistry (Wacker Chemie) (HDK), Dow Corning (Dow Corning), heili (Heraeus) (Zandosil), dekkama Corporation (Tokuyama Corporation) (Reolosil), oci (konasil), ukan kalush chemical company (Orisil), and xusui chemical (XYSIL). AEROSIL R812 fumed silica (available from winning resources efficiency Inc.) is particularly suitable. Fumed silica can be dispersed in the polymeric binder (a) and/or curing agent (b) or another resin prior to addition to the curable film-forming composition. Additionally or alternatively, the fumed silica dispersion can be added to the curable film-forming composition along with the non-aqueous dispersion (c) as a "rheology-modifying" package.

Typically, the fumed silica (d) is present in the curable film-forming composition in an amount of at least 0.5 weight percent, such as at least 1 weight percent, based on the total weight of resin solids in the curable film-forming composition. Further, the fumed silica (d) can be present in the curable film-forming composition in an amount of up to 5 weight percent or up to 4 weight percent. The total combined amount of (c) and (d) in the curable film-forming composition is 1 to 15 weight percent of the resin solids, typically 2 to 12 weight percent of the resin solids, often 3 to 8 weight percent of the resin solids.

As used herein, the phrase "based on the total weight of resin solids" of the composition means that the amount of components added during formation of the composition is based on the total weight of resin solids (non-volatiles) of the film-forming material, including the crosslinker, reactive diluent, and polymer present during formation of the composition, but does not include any water, solvent, or any additive solids, such as hindered amine stabilizers, photoinitiators, pigments (including extender pigments and fillers), flow modifiers, catalysts, and UV light absorbers.

When the curable film-forming composition of the present invention is used in a multi-component composite coating, the use of the non-aqueous dispersion (c) of the dispersed polymerization reaction product generally improves the "hold-out" between coatings. As used herein, the term maintaining refers to preventing or minimizing significant mixing between the first applied uncured coating composition and the subsequently applied uncured coating composition, i.e., the layers remain largely separate and distinct. This mixing occurs when solvent from a subsequently applied coating composition migrates into a previously applied coating. Thus, the present invention achieves maintaining separate and distinct layers in wet-wet or wet-wet applications. Coating systems that do not have good maintenance between the layers may have a poor appearance, for example a dull or poor long and/or short wave appearance as defined below.

In certain embodiments of the present invention, the curable film-forming composition further comprises a colloidal silica other than the fumed silica described above. This is particularly desirable when the curable film-forming composition is used as an outermost coating layer, such as a clear top coat, in a multi-layer coating system. Any colloidal silica may be used; it is believed that it can provide scratch resistance to the composition after being applied as a coating to a substrate and cured. A specific example is colloidal silica MT-ST available from Nissan Chemical Industries. As presented in the examples below, the colloidal silica may be dispersed in a separate resin prior to addition to the curable film-forming composition.

The curable film-forming compositions of the present invention may additionally comprise other optional ingredients commonly used in such compositions. For example, the composition may further comprise a hindered amine light stabilizer for UV degradation resistance. Such hindered amine light stabilizers include those disclosed in U.S. patent No. 5,260,135. When used, they are present in the film-forming composition in an amount of from 0.1 to 2 weight percent, based on the total weight of resin solids in the composition. Other optional additives such as colorants, plasticizers, abrasion resistant particles, film reinforcing particles, fillers, catalysts, e.g., dodecylbenzene sulfonic acid blocked with diisopropanolamine or N, N-dimethyldodecylamine, antioxidants, biocides, defoamers, surfactants, wetting agents, dispersing aids, adhesion promoters, UV light absorbers and stabilizers, organic cosolvents, reactive diluents, grinding media, and other common adjuvants or combinations thereof may be included.

Examples of suitable reactive diluents include epoxy functional materials, including monoepoxides and polyepoxides. A specific example of such a reactive diluent is 3, 4-epoxycyclohexylmethyl 3, 4-epoxycyclohexanecarboxylate, available from Terry corporation (Trico) (name ACHWL CER 4221). As noted above, the reactive diluent contributes to the resin solids content of the composition.

As used herein, the term "colorant" refers to any substance that imparts color and/or other opacity and/or other visual effect to a composition. The colorant can be added to the coating in any suitable form, such as discrete particles, dispersions, solutions, and/or flakes. A single colorant or a mixture of two or more colorants can be used in the coating of the present invention.

Exemplary colorants include pigments, dyes, and tints, such as those used in the coatings industry and/or listed in the toner manufacturers association (DCMA) as well as special effect compositions. The colorant may comprise, for example, a finely divided solid powder that is insoluble but wettable under the conditions of use. The colorant may be organic or inorganic, and may be aggregated or non-aggregated. The colorant may be incorporated into the coating by grinding or simple mixing. The colorants may be incorporated by milling into the coating using a milling vehicle, such as an acrylic milling vehicle, the use of which is familiar to those skilled in the art.

Exemplary pigments and/or pigment compositions include, but are not limited to, carbazole dioxazine crude pigment, azo, monoazo, disazo, naphthol AS, salt forms (lakes), benzimidazolone, condensation compounds (condensates), metal complexes, isoindolinones, isoindolines and polycyclic phthalocyanines, quinacridones, perylenes, perinones, diketopyrrolopyrroles, thioindigoids, anthraquinones, indanthrones, anthrapyrimidines, xanthones, pyranthrones, anthanthrones, dioxazines, triarylcarboniums, quinophthalone pigments, diketopyrrolopyrrole reds ("DPPBO red"), titanium dioxide, carbon black, and mixtures thereof. The terms "pigment" and "colored filler" may be used interchangeably.

Exemplary dyes include, but are not limited to, solvent and/or aqueous based dyes such as acid dyes, azo dyes, basic dyes, direct dyes, disperse dyes, reactive dyes, solvent dyes, sulfur dyes, mordant dyes such as bismuth vanadate, anthraquinone, perylene, aluminum, quinacridone, thiazole, thiazine, azo, indigo, nitro, nitroso, oxazine, phthalocyanine, quinoline, stilbene, and triphenylmethane.

As noted above, the colorant may be in the form of a dispersion, including but not limited to a nanoparticle dispersion. Nanoparticle dispersions can include one or more highly dispersed nanoparticle colorants and/or colorant particles that produce a desired visible color and/or opacity and/or visual effect. The nanoparticle dispersion may comprise a colorant, for example a pigment or dye having a particle size of less than 150nm, for example less than 70nm or less than 30 nm. Nanoparticles can be produced by milling an organic or inorganic pigment raw material using a milling medium having a particle size of less than 0.5 mm. Exemplary nanoparticle dispersions and methods of making the same are identified in U.S. Pat. No. 6,875,800B2, which is incorporated herein by reference. Nanoparticle dispersions can also be produced by crystallization, precipitation, gas phase condensation, and chemical abrasion (i.e., partial dissolution). To minimize re-aggregation of the nanoparticles within the coating, a dispersion of resin-coated nanoparticles may be used. As used herein, "dispersion of resin-coated nanoparticles" refers to a continuous phase in which discrete "composite microparticles" are dispersed, including nanoparticles and resin coatings on nanoparticles. Exemplary dispersions of resin-coated nanoparticles and methods of making the same are identified in U.S. application No. 10/876,315 (filed 24/6/2004 and published as U.S. patent application publication No. 2005/0287348, published as 12/29/2005, which is incorporated herein by reference) and U.S. provisional application No. 60/482,167 (filed 24/6/2003, which is also incorporated herein by reference).

Exemplary special effect compositions that can be used in the coatings of the present invention comprise pigments and/or compositions that produce one or more appearance effects, such as reflectance, pearlescence, metallic sheen, phosphorescence, fluorescence, photochromism, photosensitivity, thermochromism, goniochromism and/or color change. Additional special effect compositions may provide other perceptible properties, such as reflectivity, opacity, or texture. The special effect composition may produce a color shift such that the color of the coating changes when the coating is viewed at different angles. Exemplary color effect compositions are identified in U.S. Pat. No. 6,894,086, which is incorporated herein by reference. Additional color effect compositions may comprise transparent coated mica and/or synthetic mica, coated silica, coated alumina, transparent liquid crystal pigments, liquid crystal coatings, and/or any composition wherein interference is caused by refractive index differences within the material and not by refractive index differences between the surface of the material and air.

Photosensitive compositions and/or photochromic compositions whose color reversibly changes when exposed to one or more light sources can be used in the coatings of the present invention. Photochromic and/or photosensitive compositions can be activated by exposure to radiation of a particular wavelength. When the composition is excited, the molecular structure changes and the changed structure exhibits a new color that is different from the original color of the composition. Upon release of the exposure to radiation, the photochromic and/or photosensitive composition can return to a resting state in which the original color of the composition is restored. In one example, the photochromic and/or photosensitive composition can be colorless in a non-excited state and exhibit color in an excited state. A complete color change may occur in milliseconds to minutes, for example 20 seconds to 60 seconds. Exemplary photochromic and/or photosensitive compositions include photochromic dyes.

The photosensitive composition and/or photochromic composition can be associated with and/or at least partially bound, for example by covalent bonding, to the polymeric material of the polymer and/or polymerizable component. Photosensitive compositions and/or photochromic compositions that are associated with and/or at least partially bound to polymers and/or polymerizable components have minimal coating migration compared to some coatings in which the photosensitive composition may migrate out of the coating and crystallize into the substrate. Exemplary photosensitive and/or photochromic compositions and methods of making the same are identified in U.S. application serial No. 10/892,919 (filed 7/16/2004, now U.S. patent No. 8,153,344, and which is incorporated herein by reference).

In general, the colorant can be present in the coating composition in any amount sufficient to impart a desired property, visual, and/or color effect. The colorant may comprise 1 to 65 weight percent of the composition of the present invention, such as 3 to 40 weight percent or 5 to 35 weight percent, where weight percent is based on the total weight of the composition.

Substrates to which the compositions of the present invention may be applied include rigid metal substrates such as ferrous metal, aluminum alloys, copper and other metal and alloy substrates. Ferrous metal substrates used in the practice of the present invention may comprise iron, steel and alloys thereof. Non-limiting examples of useful steel materials include cold rolled steel, galvanized (zinc coated) steel, electrogalvanized steel, stainless steel, pickled steel, zinc-iron alloys such as GALVANNEAL, and combinations thereof. Combinations or composites of ferrous and non-ferrous metals may also be used. The substrate may alternatively comprise a polymer or composite, such as a fiberglass composite. Automotive parts, which are typically formed from thermoplastic and thermoset materials, include bumpers and trim parts.

Steel substrates (e.g., cold rolled steel or any of the steel substrates listed above) coated with weldable zinc-rich or iron phosphide-rich organic coatings are also suitable for use in the present invention. Such solderable coating compositions are disclosed in U.S. Pat. nos. 4,157,924 and 4,186,036. Cold rolled steel is also suitable when pretreated with suitable solutions known in the art, such as metal phosphate solutions, aqueous solutions containing at least one group IIIB or IVB metal, organophosphate solutions, organophosphonate solutions, and combinations thereof, as discussed below. Examples of aluminum alloys include those used in the automotive or aerospace industries, such as 2000, 6000, or 7000 series aluminum; 2024. 7075, 6061 are specific examples. The alloys may be unclad or they may contain a cladding layer on one or more surfaces, the cladding layer consisting of an aluminum alloy different from the substrate/bulk alloy underlying the cladding layer.

The substrate may alternatively comprise more than one metal or metal alloy, as the substrate may be a combination of two or more metal substrates assembled together, for example a hot dip galvanized steel assembled with an aluminum substrate. The substrate may comprise a part of a vehicle. "vehicle" is used herein in its broadest sense and encompasses all types of vehicles such as, but not limited to, airplanes, helicopters, cars, trucks, buses, vans, golf carts, motorcycles, bicycles, trams, tanks, and the like. It will be appreciated that the portion of the vehicle coated according to the invention may vary depending on the reason for which the coating is used.

The shape of the metal substrate may be in the form of a sheet, plate, strip, bar or any desired shape, but is typically in the form of an automotive part, such as a body, door, fender, hood or bumper. The thickness of the substrate may vary depending on the application.

When there is no intermediate coating between the substrate and the curable film-forming composition, the curable film-forming composition can be applied directly to the metal substrate. This means that the substrate can be bare, as described below, or can be treated with one or more pretreatment compositions, as described below, but the substrate is not coated with any coating composition, such as an electrodepositable composition or a primer composition, prior to application of the curable film-forming composition of the present invention.

As described above, the substrate to be used may be a bare metal substrate. By "bare" is meant the original metal substrate without any pretreatment composition, such as a conventional phosphating bath, heavy metal rinse, or the like. Further, the bare metal substrate used in the present invention may be a cut edge of the substrate that is otherwise treated and/or coated on the remainder of its surface. Alternatively, the substrate may undergo one or more processing steps known in the art prior to application of the curable film-forming composition.

The substrate may optionally be cleaned using conventional cleaning procedures and materials. These will contain weakly or strongly alkaline cleaners such as those commercially available and conventionally used in metal pretreatment processes. Examples of alkaline cleaners include Chemkleen 163 and Chemkleen 177, both available from PPG Industries, pre-treatments and Specialty Products (PPG Industries, pretreatments and Specialty Products). Such cleaners are typically performed after and/or before a water rinse. The metal surface may also be rinsed with an acidic aqueous solution after or instead of cleaning with an alkaline cleaner. Examples of rinse solutions include weakly or strongly acidic cleaners, such as dilute nitric acid solutions that are commercially available and are routinely used in metal pretreatment processes.

According to the present invention, at least a portion of the cleaned aluminum substrate surface may be mechanically or chemically deoxidized. As used herein, the term "deoxygenation" refers to the removal of an oxide layer on the surface of a substrate in order to promote uniform deposition of a pretreatment composition (as described below), as well as to promote adhesion of a pretreatment composition coating to the surface of the substrate. Suitable oxygen scavengers are familiar to the person skilled in the art. Typical mechanical deoxidizers can uniformly roughen the surface of the substrate, such as by using a scrubbing pad or a cleaning pad. Typical chemical DEOXIDIZERs include, for example, acid-based DEOXIDIZERs such as phosphoric acid, nitric acid, fluoroboric acid, sulfuric acid, chromic acid, hydrofluoric acid, and ammonium bifluoride, or the Amchem 7/17 DEOXIDIZER (available from Henkel Technologies, midison, michigan), OAKITE DEOXIDIZER LNC (available from cament (chemill)), TURCO DEOXIDIZER 6 (available from Henkel), or combinations thereof. Typically, the chemical oxygen scavenger comprises a carrier, typically an aqueous medium, such that the oxygen scavenger may be in the form of a solution or dispersion in the carrier, in which case the solution or dispersion may be contacted with the substrate by any of a variety of known techniques, such as dipping or immersion, spraying, intermittent spraying, spraying after dipping, dipping after spraying, brushing, or roller coating.

The metal substrate may optionally be pretreated with any suitable solution known in the art, such as a metal phosphate solution, an aqueous solution containing at least one group IIIB or IVB metal, an organophosphate solution, an organophosphonate solution, and combinations thereof. The pretreatment solution may be substantially free of heavy metals that are harmful to the environment, such as chromium and nickel. Suitable phosphate conversion coating compositions may be any of those known in the art that are free of heavy metals. Examples include zinc phosphate (which is the most commonly used), iron phosphate, manganese phosphate, calcium phosphate, magnesium phosphate, cobalt phosphate, zinc iron phosphate, zinc manganese phosphate, zinc calcium phosphate, and other types of layers that may contain one or more multivalent cations. Phosphating compositions are known to those skilled in the art and are described in U.S. patents 4,941,930, 5,238,506 and 5,653,790.

The IIIB or IVB transition metals and rare earth metals referred to herein are those included in these groups of the CAS periodic table of elements, as shown in Handbook of Chemistry and Physics, 63 rd edition (1983).

Typical group IIIB and IVB transition metal compounds and rare earth metal compounds are compounds of zirconium, titanium, hafnium, yttrium and cerium and mixtures thereof. Typical zirconium compounds may be selected from hexafluorozirconic acid, alkali metal and ammonium salts thereof, ammonium zirconium carbonate, zirconyl nitrate, zirconium carboxylates and zirconium hydroxy carboxylates, such as hydrofluorozirconic acid, zirconium acetate, zirconium oxalate, ammonium zirconium hydroxy acetate, ammonium zirconium lactate, ammonium zirconium citrate and mixtures thereof. Hexafluorozirconic acid is most commonly used. An example of a titanium compound is fluorotitanic acid and salts thereof. An example of a hafnium compound is hafnium nitrate. An example of a yttrium compound is yttrium nitrate. An example of a cerium compound is cerium nitrate.

Typical compositions to be used in the pretreatment step include non-conductive organophosphate and organophosphate pretreatment compositions such as those disclosed in U.S. patents 5,294,265 and 5,306,526. Such organophosphate or organophosphonate pre-treatment agents are commercially available from PPG Industries, Inc. (PPG Industries, Inc.) (name))。

In the aerospace industry, anodizing surface treatments and chromium-based conversion coatings/pretreaters are commonly used on aluminum alloy substrates. Examples of anodizing surface treatment agents would be chromic acid anodizing, phosphoric acid anodizingOxidation, boric acid-sulfuric acid anodic oxidation, tartaric acid anodic oxidation and sulfuric acid anodic oxidation. Chromium-based conversion coatings will contain hexavalent chromium types, such as those available from HangaoM-CR1200, and trivalent chromium species, e.g. from HangaoM-CR T5900。

The curable film-forming composition of the present invention can be applied to a substrate using conventional techniques, including dipping or immersion, spraying, intermittent spraying, spraying after dipping, dipping after spraying, brushing or rolling, and non-atomizing techniques such as material spraying

The coating composition of the present invention may be used alone as a protective layer or may be used as a single coating (layer). Alternatively, the compositions of the present invention may be combined as a primer, a basecoat and/or a topcoat. Accordingly, the present invention provides a coated substrate comprising a substrate and a film-forming composition applied to a surface of the substrate to form a coating; wherein the film-forming composition comprises any of the curable film-forming compositions described above. The present invention also provides a multilayer coated article comprising a first film-forming composition applied to a substrate to form a colored base coat layer and a second transparent film-forming composition applied on top of the base coat layer to form a transparent top coat layer, wherein the transparent film-forming composition comprises the curable film-forming composition of the present invention as described above. The term "transparent" as used, for example, in conjunction with a substrate, film, material, and/or coating, means that the substrate, coating, film, and/or material indicated is optically transparent and has the property of transmitting light without significant scattering so that objects at a greater distance are fully visible. As used herein, a clear coating exhibits a visible light transmission (transmission), such as using visible light, of at least 70% (100 x10 with the formula% transmission ═ 100x10^IL/10As defined). In an exemplary method of determining light transmission, a substrate having an applied coating is mounted between an electromagnetic radiation emitter and a receiver antenna with the coated side of the substrate facing the emitter. The Insertion Loss (IL) is measured and refers to the amount of transmitted signal that is not detected at the receiver. This method assumes a "lossless" condition in which the substrate does not absorb or absorbs a small amount of the incident frequency. The% transmission is calculated according to the above formula.

Suitable primer layers include any of those known in the art and may be aqueous, solvent-borne or powdered. The base coat typically comprises a film-forming resin, a crosslinking material, and a pigment. Non-limiting examples of suitable basecoat compositions include waterborne basecoats, such as those described in U.S. Pat. nos. 4,403,003; 4,147,679, respectively; and 5,071,904.

After each composition is applied to a substrate, a film is formed on the substrate surface by driving the solvent (i.e., organic solvent and/or water) out of the film by heat or by an air drying period. Suitable drying conditions will depend on the particular composition and/or application, but in some examples, drying at a temperature of about 70 to 250 ° f (27 to 121 ℃) for about 1 to 5 minutes is sufficient. More than one coating of the composition of the present invention may be applied if desired. Typically, between coatings, the previously applied coating is flashed; that is, exposure to ambient conditions for a desired time. Ambient temperatures are typically in the range of 60 to 90 ° f (15.6 to 32.2 ℃), such as typical room temperature, 72 ° f (22.2 ℃).

The thickness of the coating is typically 0.1 to 3 mils (2.5 to 75 micrometers), such as 0.2 to 2.0 mils (5.0 to 50 micrometers). The coating composition may then be heated. During the curing operation, the solvent is driven off and the crosslinkable components of the composition are crosslinked. The heating and curing operation is sometimes conducted at a temperature in the range of 70 to 250 ° f (27 to 121 ℃), although lower or higher temperatures may be used if desired. As previously mentioned, the coating of the present invention may also be cured without heating or a drying step. Further, the first coating composition can be applied first and then the second coating composition applied "wet-wet" thereto, or at least one basecoat can be applied on top of the primer prior to curing of the primer and then the clearcoat is applied over the basecoat prior to curing of the basecoat (i.e., "wet-wet" or "3 wet"), the entire multilayer coating stack being cured simultaneously in a compact process (also referred to as 3C 1B). Alternatively, each coating composition may be cured before the next coating composition is applied.

In the preparation of the multilayer coated article of the present invention, a liquid or powder primer may be applied to the substrate prior to application of the first film-forming composition to form a primer coating on the substrate surface, and then the first film-forming composition may be applied directly onto the primer coating. Again, the primer coating may be cured prior to application of the first film-forming composition, or at least one basecoat may be applied on top of the primer prior to primer curing, followed by application of a clearcoat over the basecoat prior to the basecoat being cured in a "wet-wet" process, followed by simultaneous curing of the entire multilayer coating stack in a compact process. After all of the coating composition has been applied to the substrate, the coated substrate may be maintained at a temperature and for a sufficient time to substantially cure the composite coating. Application and curing methods and conditions may be as described above.

Surface waviness is an indication of surface roughness and can be measured using a wave scanning instrument, such as BYK Wavescan Plus available from becker nano, USA (BYK Gardner USA), which measures surface topography via optical spectroscopy. A wave scanning instrument uses a point source (i.e., laser) to illuminate a surface over a predetermined distance, e.g., 10 centimeters, at an angle of incidence of 60 °. The reflected light is measured at the same but opposite angle. The maximum signal is detected when the light beam hits a "peak" or "valley" of the surface; when the beam hits the "slope" of the peak/valley, a minimum signal is registered. The measurement signal frequency is equal to twice the spatial frequency of the coating surface topography. The surface "waviness" is divided into "long wavelength/LW (1.2-12 mm)" and "short wavelength/SW (0.3-1.2 mm)" to simulate the visual assessment of the human eye. The data is separated into long and short wave signals using a mathematical filter function. Each ranging from 0 to 50. The long wavelength wave length represents a variation in amplitude of the long wave signal, and the short wavelength wave length represents a variation in amplitude of the short wave signal. Long and short wavelength waviness of the coating surface can indirectly measure factors affecting the topography, such as substrate roughness; as well as the flow and leveling properties of the coating. The long wave value can be determined using a BYK Wavescan Plus instrument according to the manufacturer's recommended protocol. A lower amplitude of the long wavelength value indicates a smoother appearance of the coating.

After the curable film-forming composition of the present invention is applied to a substrate and cured to form a cured coating, the cured coating formed from the curable film-forming composition typically exhibits a wavelength value at least 20% lower than a similarly cured coating formed from a composition that does not contain the aforementioned non-aqueous dispersion (c) and fumed silica (d). This is evident when the composition is applied to both horizontally and vertically oriented substrate surfaces.

Each feature and example described above, and combinations thereof, can be said to be encompassed by the present invention. Accordingly, the present invention is directed to the following non-limiting aspects:

1. a curable film-forming composition comprising:

(a) a polymeric binder comprising epoxy functional groups;

(b) a curing agent comprising an acid functional group that reacts with the epoxy functional group of (a);

(c) a non-aqueous dispersion comprising a dispersion polymerization reaction product of a reaction mixture comprising ethylenically unsaturated monomers ("core monomers") and ethylenically unsaturated nonlinear random acrylic polymer stabilizer, wherein the dispersion polymerization reaction product in the non-aqueous dispersion is present in the curable film-forming composition in an amount of from 0.5 to 10 weight percent, such as from 1 to 8 weight percent, based on the total weight of resin solids in the curable film-forming composition, and wherein the dispersion polymerization reaction product is different from the polymeric binder (a); and

(d) fumed silica, which is present in the curable film-forming composition in an amount of 0.5 to 5 weight percent, such as 1 to 4 weight percent, based on the total weight of resin solids in the curable film-forming composition.

2. The curable film-forming composition of aspect 1, comprising 5 to 50 wt% of polymeric binder (a), for example 10 to 35 wt% or 25 to 30 wt%, each based on the total weight of resin solids in the curable film-forming composition.

3. The curable film-forming composition of aspect 1 or 2, comprising 5 to 75 wt% of curing agent (b), for example 10 to 60 wt% or 15 to 55 wt% or 5 to 50 wt% or 5 to 60 wt%, 10 to 50 wt%, 10 to 75 wt%, 15 to 50 wt%, 15 to 60 wt%, and 15 to 75 wt%, all based on the total weight of resin solids in the curable film-forming composition.

4. The curable film-forming composition of any one of aspects 1 to 3, wherein the polymeric binder (a) is selected from one or more of the following: acrylic polymers, polyesters, polyurethanes, polyamides, polyethers, polythioethers, polythioesters, polyenes, and epoxy resins.

5. The curable film-forming composition of aspect 4, wherein the polymeric binder (a) comprises an acrylic and/or polyester polymer.

6. The curable film-forming composition of any one of aspects 1-5, wherein the curing agent (b) comprises an acid-functional polyester or an acrylic polymer.

7. The curable film-forming composition of any one of aspects 1 to 5, wherein the curing agent (b) comprises a half-acid ester based on the condensation of an aliphatic polyol with an aliphatic and/or aromatic polycarboxylic acid or anhydride.

8. The curable film-forming composition of any one of aspects 1-7, wherein the acrylic polymeric stabilizer comprises 50 or more weight percent of residues derived from (meth) acrylic monomers, based on the total weight of the polymer.

9. The curable film-forming composition of any one of aspects 1-8, wherein the acrylic polymeric stabilizer is prepared from a reaction mixture comprising one or more multifunctional ethylenically unsaturated monomers.

10. The curable film-forming composition of aspect 9, wherein the multifunctional ethylenically unsaturated monomer is used in an amount of 0.1 to 10 weight percent, such as 0.25 to 5 weight percent or 0.5 to 2 weight percent, all based on the total weight of monomers used to prepare the acrylic polymeric stabilizer.

11. The curable film-forming composition of aspect 9 or 10, wherein the multifunctional ethylenically unsaturated monomer comprises allyl (meth) acrylate and/or an alkylene glycol di (meth) acrylate, such as 1, 6-hexanediol diacrylate.

12. The curable film-forming composition of any one of aspects 1-11, wherein the acrylic polymeric stabilizer is prepared from a reaction mixture comprising 90 or more weight percent of (meth) acrylic monomers, based on the total weight of monomers used to form the acrylic polymeric stabilizer.

13. The curable film-forming composition of any one of aspects 12, wherein the acrylic polymeric stabilizer is prepared from a reaction mixture comprising 95 or greater weight percent of (meth) acrylic monomer, for example 100 weight percent of (meth) acrylic monomer, based on the total weight of monomers used to form the acrylic polymeric stabilizer.

14. The curable film-forming composition of any one of aspects 1-13, wherein the acrylic polymeric stabilizer is prepared from a reaction mixture comprising 30 or less weight percent of a polar (meth) acrylic monomer, such as a hydroxy-functional (meth) acrylic monomer, for example 20 or less weight percent or 15 or less weight percent or 10 or less weight percent, each based on the total weight of monomers used to form the acrylic polymeric stabilizer.

15. The curable film-forming composition of any one of aspects 1-13, wherein the acrylic polymeric stabilizer is prepared from a reaction mixture comprising 50 or more weight percent of non-polar (meth) acrylic monomer, such as 60 or more weight percent or 70 or more weight percent or 80 or more weight percent, each based on the total weight of monomers used to form the acrylic polymeric stabilizer.

16. The curable film-forming composition of any one of aspects 1-15, wherein the acrylic polymeric stabilizer is prepared from a reaction mixture comprising one or more multifunctional ethylenically unsaturated monomers selected from the group consisting of methyl (meth) acrylate, ethyl (meth) acrylate, n-butyl (meth) acrylate, isobutyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, isobornyl (meth) acrylate, 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, meth) acrylic acid, glycidyl (meth) acrylate, styrene, alpha-methylstyrene, lauryl (meth) acrylate, stearyl (meth) acrylate, and one or more additional ethylenically unsaturated monomers, Itaconic acid and mixtures thereof.

17. The curable film-forming composition of any one of aspects 1-16, wherein the reaction mixture comprising ethylenically unsaturated monomers ("core monomers") reacted with the acrylic polymeric stabilizer comprises one or more multifunctional ethylenically unsaturated monomers.

18. The curable film-forming composition of aspect 17, wherein the multifunctional monomer is used in an amount of >0 to 20 wt%, for example 1 to 10 wt%, based on the total weight of monomers reacted with the acrylic polymeric stabilizer.

19. The curable film-forming composition of any one of aspects 1-18, wherein the reaction mixture comprising ethylenically unsaturated monomers ("core monomers") reacted with the acrylic polymeric stabilizer comprises one or more ethylenically unsaturated monomers selected from the group consisting of: methyl (meth) acrylate, ethyl (meth) acrylate, n-butyl (meth) acrylate, isobutyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, isobornyl (meth) acrylate, 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, (meth) acrylic acid, glycidyl (meth) acrylate, styrene, alpha-methylstyrene, lauryl (meth) acrylate, stearyl (meth) acrylate, itaconic acid, and mixtures thereof.

20. The curable film-forming composition of any one of aspects 1-19, wherein the reaction mixture comprising ethylenically unsaturated monomer ("core monomer") reacted with the acrylic polymeric stabilizer comprises less than 90 wt% polar and/or functional monomer.

21. The curable film-forming composition of any one of aspects 1-20, wherein the reaction mixture used to prepare the dispersion polymerization reaction product further comprises an aliphatic polyester stabilized seed polymer.

22. The curable film-forming composition of aspect 21, wherein the aliphatic polyester stabilized seed polymer is prepared from a seed stage stabilizer and one or more seed monomers.

23. The curable film-forming composition of aspect 22, wherein the seed monomer is one or more ethylenically unsaturated monomers, such as (meth) acrylate monomers, such as methyl methacrylate.

24. The curable film-forming composition of any one of aspects 21-23, wherein the seed stage stabilizer comprises two segments: an aliphatic polyester component and a stabilizer component having a polarity different from that of the polyester.

25. The curable film-forming composition of aspect 24, wherein the aliphatic polyester component has a carbon/oxygen ratio of 4:1 to 20:1, such as 6:1 to 12: 1.

26. The curable film-forming composition of aspect 25, wherein the aliphatic polyester component is poly-12-hydroxystearic acid.

27. The curable film-forming composition of any one of aspects 24-26, wherein the seed stage stabilizer comprises 20 to 65 wt.% of an aliphatic polyester component, such as 25 to 60 wt.% or 30 to 55 wt.%, or 33 to 53 wt.% polyester, wherein wt.% is based on the total weight of the components of the seed stage stabilizer.

28. The curable film-forming composition of aspect 26 or 27, wherein the seed stage stabilizer is prepared by: reacting poly-12-hydroxystearic acid with a compound comprising a (meth) acrylate functional group and a second type of functional group capable of reacting with the hydroxyl or acid functional groups of the poly-12-hydroxystearic acid to form a polyester intermediate, and then reacting the polyester intermediate with one or more ethylenically unsaturated seed monomers, for example, selected from (meth) acrylic acid, methyl (meth) acrylate, ethyl (meth) acrylate, n-butyl (meth) acrylate, isobutyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, isobornyl (meth) acrylate, 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, (meth) acrylic acid, glycidyl (meth) acrylate, styrene, di (meth) acrylate, tri (meth) acrylate, di (meth) acrylate, tri (meth) acrylate, and (meth) acrylate, Alpha-methylstyrene, lauryl (meth) acrylate, stearyl (meth) acrylate, itaconic acid, and mixtures thereof.

29. The curable film-forming composition of aspect 28, wherein the compound comprising a (meth) acrylate functional group and a second type of functional group capable of reacting with a hydroxyl or acid functional group of the poly-12-hydroxystearic acid to form a polyester intermediate is glycidyl (meth) acrylate.

30. The curable film-forming composition of aspect 28 or 29, wherein the polyester intermediate is reacted with a mixture of methyl methacrylate, glycidyl methacrylate, and methacrylic acid.

31. The curable film-forming composition of any one of aspects 21-30, wherein the weight ratio of the aliphatic polyester stabilized seed polymer to the ethylenically unsaturated monomer ("core monomer") in the reaction mixture forming the dispersion polymerization reaction product is from 1:100 to 20:100, such as from 5:100 to 15: 100.

32. The curable film-forming composition of any one of aspects 1-31, wherein the weight ratio of the acrylic polymeric stabilizer to the ethylenically unsaturated monomer ("core monomer") in the reaction mixture forming the dispersion polymerization reaction product is from 10:100 to 100:10, such as from 20:100 to 100: 20.

33. The curable film-forming composition of any one of aspects 1-32, wherein the dispersion polymerization reaction product in the non-aqueous dispersion has a Z-average particle size of one micron or less, e.g., 500nm or less or 250nm or less or 200 to 250nm, as measured by dynamic light scattering.

34. The curable film-forming composition of any one of aspects 1-33, wherein the dispersion polymerization reaction product and the fumed silica (d) in the non-aqueous dispersion (c) are present in the curable film-forming composition in a total amount of 1 to 15 wt.%, e.g., 2 to 12 wt.%, based on the total weight of resin solids in the curable film-forming composition.

35. The curable film-forming composition of any one of aspects 1-34, wherein the solids content of the non-aqueous dispersion (c) is 15 to 70 wt.%, e.g., 20 to 65 wt.% or 22 to 62 wt.%, or 32 to 52 wt.%.

36. A multilayer coated article comprising a first film-forming composition applied to a substrate to form a colored base coat layer and a second transparent film-forming composition applied on top of the base coat layer to form a transparent top coat layer, wherein the transparent film-forming composition comprises the curable film-forming composition according to any one of aspects 1 to 35.

37. The multilayer coated article of aspect 36, wherein the transparent film-forming composition further comprises colloidal silica.

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

Non-aqueous dispersions (NAD) were prepared as follows (examples 1 to 4):

example 1

Polyester intermediate 1 for seed stage stabilizer was prepared according to example 1 in U.S. patent application publication No. 2014/0128508a 1.

Example 2

Aliphatic seed stage stabilizer 2 was prepared according to example 2 in U.S. patent application publication No. 2014/0128508a 1.

Example 3

Hyperbranched acrylic stabilizer 3 was prepared as follows:

¹AROMATIC 100 is a solvent produced from petroleum-based raw materials, AROMATIC containingIn an amount of at least 99%, consisting essentially of C9-10 dialkyl and trialkyl benzenes available from Exxon Mobil chemical.

²LUPEROX 270 is tert-butyl-peroxy-3, 5, 5-trimethylhexanoate, available from Arkema, Inc.

³ARMEEN DMCD is a dimethyl cocoamine surfactant available from Aksu Nobel Chemicals, Inc. (Akzo Nobel Chemicals B.V.).

Acrylic stabilizer 3 was prepared from the above ingredients according to example 3 in U.S. patent application publication No. 2014/0128508a1, with the following exceptions: the reaction mixture was not cooled to 110 ℃ but was kept at 125 ℃. Charge #4 was added over 10 minutes at 125 deg.C, and the reaction mixture was then held at 125 deg.C for 1 hour. After 1 hour hold, the nitrogen inlet was switched to 95/5% mole ratio N₂/O₂The mixture was bubbled. After 30 minutes of bubbling, charge #5 was added to the reaction flask (over 10 minutes) followed by charge #6 (over 10 minutes). The reaction mixture was kept at 110 ℃ for 2 hours.

Example 4

The non-aqueous dispersion was prepared as follows:

¹ISOPAR E is a solvent produced from C8 and C9 isoparaffins, and is available from exxonmobil chemical.

²VAZO 67 is 2,2' -azobis (2-methylbutyronitrile) available from The Chemours Company.

NAD was prepared from the above ingredients according to example 5 in U.S. patent application publication No. 2014/0128508a1 with the following exceptions: charge #1 was charged to a 5-liter 4-necked flask equipped with a motor-driven steel stir blade, thermocouple, nitrogen inlet, and water-cooled condenser. The reaction mixture was heated to 100 ℃ via a temperature feedback control device by a heating mantle controlled by a thermocouple. Feeds #2 and #3 were added dropwise over 30 minutes via an addition funnel, and the reaction mixture was then held at 100 ℃ for 30 minutes. After holding, feeds #4 and #5 were added over 4 hours, and then the reaction mixture was held at 100 ℃ for 2 hours.

Six clear coat compositions were prepared from a mixture of the following ingredients. Example a presents the preparation of a curable film-forming composition according to the present invention; examples B to F are comparative; examples B and C are comparative in that they do not contain NAD; examples D to F are comparative in that they do not contain fumed silica.

TABLE 1

¹Mixtures of dimethyl dicarboxylates (dimethyl succinate, dimethyl glutarate and dimethyl adipate) available from Invista Corporation

²Hindered amine light stabilizers, commercially available from Taiwan Yongoto Chemical Taiwan

³Epoxy-functional acrylic polymers prepared as described in U.S. Pat. No. 5,196,485, example A

⁴3, 4-Epoxycyclohexanecarboxylic acid 3, 4-epoxycyclohexylmethyl ester reactive diluent available from Terry chemical company, China

⁵Methylated melamine-formaldehyde curing agents, commercially available from Intel Melamine (INEOS Melamines).

⁶Polymeric non-silicone general purpose additives available from Taier (Dynea)

⁷Polyether modified polydimethylsiloxane additive available from Bik (Altana Group)

⁸Acrylic polymer based additives are available from Nanhimoto Chemicals, Ltd.

⁹UV absorbers, commercially available from Chitec Technology, IncCo.,Ltd.)。

¹⁰Preparation according to U.S. Pat. No. 5,196,485, example G (70% solids in a solvent mixture of 5% propanol and 95% n-butyl acetate)

¹¹Prepared according to U.S. Pat. No. 5,196,485, example J (73% solids in 26% mineral spirits and 74% n-butyl acetate)

¹²Prepared according to U.S. Pat. No. 5,196,485, example H (80% solids in a mixed solvent of 17% ethanol and 83% methyl isobutyl ketone)

¹³A dispersion of 8% AEROSIL R812 silica (available from winning resources efficiency corporation) mixed with 42% amyl alcohol and 50% half ester resin as disclosed in example G of U.S. patent No. 5,196,485.

¹⁴Colloidal silica dispersion a is colloidal silica MT-ST available from the commodity chemical industry dispersed in a modified silicone polyol resin. The dispersion is made in a stepwise process:

1) the silicone polyol resin was synthesized using SILRES SY816VP (methyl hydrogen polysiloxane resin, available from Wacker Chemie AG) and trimethylolpropane monoallyl ether, and hydrosilation was used to form a 100% solids silicone polyol resin having a GPC weight average molecular weight of 6,500.

2) To the silicone polyol resin was added methyl amyl ketone solvent to obtain 72% by weight solids.

3) To the reduced siloxane polyol resin of step 2 was added daily chemical colloidal silica MT-ST (provided as a 30 wt% solids in methanol).

4) The methanol solvent was distilled off.

5) The silicone polyol resin was chemically modified with methyl HHPA and Cardura E-10 in the presence of additional methyl amyl ketone to form a final product made with 31.4 wt% SILRES SY816VP, 12.4 wt% daily chemical MT-ST colloidal silica, 18.5 wt% methyl HHPA and 37.7 wt% CARDURA E-10 using 0.0015 wt% N, N-dimethylbenzylamine catalyst.

6) The final product was a colloidal dispersion of silica particles having an average particle size of about 12nm in the silicone polyol resin, provided in methyl amyl ketone, at 74% solids by weight.

A black waterborne basecoat, commercially available as HWB9517 from PPG, was sprayed onto 4 inch x 12 inch (10cm x 30cm) steel panels coated with a PPG powder primer (PCV70500) and a PPG electrocoat (ED6100C), both commercially available from PPG, in an environment controlled to 70-75 ° f (21-24 ℃) and 60-70% relative humidity. The substrate board was obtained from ACT Test Panels, LLC of hill dall, michigan. The base coat was applied in two coats, flash between coats for 1 minute, then flash at ambient temperature for 2 minutes. The film thickness is about 0.6-0.8 mils (15-20 microns). The clearcoat examples were reduced to 90-95cP as measured by a Brookfield CAP-2000 viscometer at 100RPM using a #10 spindle. Each clearcoat was sprayed onto the basecoated panels in an environment controlled to 70-75 ° f (21-24 ℃) and 60-70% relative humidity to simulate OEM conditions. Immediately after application, a portion of the panels were oriented horizontally (H) while the other panels remained oriented vertically (V). Clear coats were applied in both coats and flash evaporated between coats for 1 minute. The clear coated panels were allowed to flash at ambient conditions for 10 minutes and then baked at 260 ° f (127 ℃) for 30 minutes. The film thickness was about 2.0 mils (50 microns).

The appearance results of the coated horizontal (H) and vertical (V) panels were measured by the beta kwascan Plus instrument according to the manufacturer's recommended protocol. "rating" is the number provided by the instrument based on the combined Long Wave (LW) and Short Wave (SW) measurements. Higher γ K rating, lower long wavelength, lower short wavelength, lower darkness value, and lower sag are more desirable for appearance.

TABLE 2

Comparative example B, which contained no non-aqueous dispersion, exhibited vertical dullness and significant vertical sag compared to the inventive composition (example a). Comparative example C, which contained no non-aqueous dispersion, and comparative examples D through F, which contained no fumed silica, exhibited inferior vertical ratings as compared to the inventive composition (example a).

While specific examples of the invention are described above for purposes of illustration, it will be evident to those skilled in the art that numerous variations of the details of the present invention may be made without departing from the scope of the invention as defined in the appended claims.