Systems and methods for coating multilayer coated metal substrates

Abstract

This disclosure relates to a system for coating a metal substrate, the system comprising: an anionicly electrodepositable coating composition comprising a film-forming polymer containing anionic salt groups and a curing agent, wherein if the film-forming polymer containing anionic salt groups is a phosphating epoxy resin, the film-forming polymer containing anionic salt groups does not contain urethane functional groups; and a non-electrodepositable coating composition comprising a corrosion inhibitor containing azoles. A method for coating a metal substrate and a multilayer coated metal substrate are also disclosed.

Description

Technical Field

[0001] This disclosure relates to systems for coating metal substrates, methods for coating metal substrates, and multilayer coated metal substrates. Background Technology

[0002] Coatings are used in electrical appliances, automobiles, aircraft, and other applications for a variety of reasons, most notably for aesthetics, corrosion protection, and / or performance enhancement, such as durability and prevention of physical damage. To improve the corrosion resistance of metallic substrates, corrosion inhibitors are typically used in coatings applied to the substrate. However, due to health and environmental concerns, evolving government regulations have led to the phase-out of certain corrosion inhibitors and other additives in coating compositions, making the production of effective coating compositions challenging. Systems and methods for improving the corrosion resistance of metallic substrates are desired. Summary of the Invention

[0003] This disclosure provides a system for coating a metal substrate, the system comprising: an anionicly electrodepositable coating composition comprising a film-forming polymer containing anionic salt groups and a curing agent, wherein if the film-forming polymer containing anionic salt groups is a phosphating epoxy resin, the film-forming polymer containing anionic salt groups does not contain urethane functional groups; and a non-electrodepositable coating composition comprising a corrosion inhibitor containing azoles.

[0004] This disclosure also provides a method for coating a metal substrate, the method comprising electrodepositing an electrodeposable coating composition described above onto at least a portion of the substrate to form an electrodeposited coating; and applying a non-electropposable coating composition described above onto at least a portion of the electrodeposited coating to form a second coating.

[0005] This disclosure further relates to a multilayer coated metal substrate comprising (a) a metal substrate; (b) an electrodeposited coating present on at least a portion of the metal substrate, wherein the electrodeposited coating comprises a film-forming polymer containing anionic salt groups and a curing agent, and if the film-forming polymer containing anionic salt groups is a phosphating epoxy resin, then the film-forming polymer containing anionic salt groups does not contain urethane functional groups; and (c) a second coating present on at least a portion of the electrodeposited coating, wherein the second coating comprises a corrosion inhibitor containing azole. Detailed Implementation

[0006] This disclosure relates to a system for coating a metal substrate, the system comprising: an anionicly electrodepositable coating composition comprising a film-forming polymer containing anionic salt groups and a curing agent, wherein if the film-forming polymer containing anionic salt groups is a phosphating epoxy resin, the film-forming polymer containing anionic salt groups does not contain urethane functional groups; and a non-electrodepositable coating composition comprising a corrosion inhibitor containing azoles.

[0007] Electrodepositable coating compositions

[0008] According to this disclosure, a system for coating a metal substrate includes an anion-electrodepositable coating composition comprising a film-forming polymer containing anion salt groups and a curing agent, wherein if the film-forming polymer containing anion salt groups is a phosphated epoxy resin, the film-forming polymer containing anion salt groups does not contain urethane functional groups.

[0009] As used herein, the term "electrodepositable coating composition" refers to a composition that can be deposited onto a conductive substrate under the influence of an applied electrical potential.

[0010] As used herein, the term "film-forming polymer containing anionic salt groups" refers to an anionic polymer that includes at least partially neutralized anionic functional groups, such as carboxylic acid groups and phosphate groups that impart a negative charge. As used herein, the term "polymer" encompasses, but is not limited to, oligomers, homopolymers, and copolymers. Film-forming polymers containing anionic salt groups may include active hydrogen functional groups. As used herein, the term "active hydrogen functional group" refers to those groups that react with isocyanates as determined by the Zerewitinoff test discussed above, and includes, for example, hydroxyl, primary or secondary amino, and thiol groups. Film-forming polymers containing anionic salt groups that include active hydrogen functional groups may be referred to as film-forming polymers containing active hydrogen and anionic salt groups. Film-forming polymers containing anionic salt groups can be used in anionic electrodepositable coating compositions.

[0011] Film-forming polymers containing anionic salt groups can include alkali-soluble film-forming polymers containing carboxylic acid groups, such as reaction products or adducts of drying oils or semi-drying fatty acid esters with dicarboxylic acids or anhydrides; and reaction products of fatty acid esters, unsaturated acids or anhydrides with any additional unsaturated modifiers that further react with polyols. Also suitable are interpolymers of at least partially neutralized hydroxyalkyl esters of unsaturated carboxylic acids, unsaturated carboxylic acids, and at least one other olefinically unsaturated monomer. Another suitable anionic electrodepositable resin includes alkyd resin-amino plastic mordants, i.e., mordants containing alkyd resins and amine-aldehyde resins. Another suitable anionic electrodepositable resin composition includes mixed esters of resin polyols.

[0012] Other acid-functionalized polymers, such as phosphated polyepoxides or phosphated addition polymers, can also be used.

[0013] As used herein, the term "phosphorylated epoxy resin" refers to an ungelled resin derived from at least polyepoxide and phosphorous acid.

[0014] Suitable polyepoxides comprise any compound or mixture of compounds having more than 1.0 epoxy group per molecule. Several polyepoxides are known in the art. Examples of polyepoxides can be found in the Handbook of Epoxy Resins, Lee and Neville, 1967, McGraw-Hill Book Company.

[0015] Polyepoxides can include polyglycidyl ethers of polyphenols such as bisphenol A. As will be understood, such polyepoxides can be prepared by etherification of polyphenols with epichlorohydrin in the presence of a base. Suitable polyphenols include, but are not limited to, 1,1-bis(4-hydroxyphenyl)ethane; 2,2-bis(4-hydroxyphenyl)propane; 1,1-bis(4-hydroxyphenyl)isobutane; 2,2-bis(4-hydroxytert-butylphenyl)propane; bis(2-hydroxynaphthyl)methane; 1,5-dihydroxynaphthalene; 1,1-bis(4-hydroxy-3-allylphenyl)ethane; and 4,4-bis(4'-hydroxyphenyl)valerate. Another class of useful polyepoxides are similarly produced from polyphenol resins.

[0016] In addition to the polyepoxides described above, addition polymers containing epoxy side groups can also be used. These polymers can be prepared by copolymerizing a variety of polymerizable olefinic unsaturated monomers, where at least one polymerizable olefinic unsaturated monomer is an epoxy-containing monomer, such as glycidyl acrylate or glycidyl methacrylate.

[0017] Suitable olefinic unsaturated monomers that do not contain groups that can react with epoxy groups can be used as comonomers. Exemplary examples of such monomers include α,β-olefinic unsaturated monomers, such as unsaturated carboxylic acid esters of saturated alcohols containing one to about eight carbon atoms, and monovinyl aromatic monomers such as styrene and vinyltoluene.

[0018] The epoxy equivalent of polyepoxides can be from 172 to 5000 g / equivalent, such as 300 to 1000 g / equivalent.

[0019] In addition to polyepoxides, the reaction mixture may contain monomeric monoepoxides, such as monoglycidyl ethers of alcohols and phenols, such as phenyl glycidyl ethers, and monocarboxylic acid glycidyl esters, such as neodecanoic acid glycidyl ester.

[0020] Phosphorous acid reacting with polyepoxides can include phosphoric acid, such as 100% orthophosphoric acid or an aqueous solution of phosphoric acid, e.g., 85% phosphoric acid. Other forms of phosphoric acid, such as superphosphoric acid, diphosphoric acid, and triphosphoric acid, can also be used. Additionally, polymeric anhydrides or partial anhydrides of phosphoric acid can be used. An aqueous solution of about 70% to 90% by weight of phosphoric acid, e.g., about 85% by weight, can be used.

[0021] Phosphorous acid reacting with polyepoxides can consist substantially of phosphoric acid. In other words, based on the total number of moles of phosphorous acid reacting with polyepoxides, phosphoric acid may optionally be present in an amount of at least 98 mol%, such as at least 99 mol%, or in some cases 100 mol%.

[0022] Alternatively, phosphonic acids and / or phosphonoids, in addition to or replacing phosphoric acid, can react with polyepoxides. Examples of phosphonic acids are organophosphonic acids having the following structures:

[0023]

[0024] Where R is an organic group, such as an organic group having a total of 1-30, such as 6-18 carbon atoms. R can be aliphatic, aromatic or a mixture of aliphatic / aromatic, and can be an unsubstituted hydrocarbon or a substituted hydrocarbon.

[0025] Examples of phosphonic acids are organic phosphonic acids having the following structures:

[0026]

[0027] R and R' are each independently a hydrogen or organic group. Examples of such groups are groups having a total of 1-30 carbon atoms, such as 6-18 carbon atoms. The organic components (R, R') of phosphonic acid can be aliphatic, aromatic, or a mixture of aliphatic / aromatic. R and R' can be unsubstituted or substituted hydrocarbons.

[0028] Representative suitable organophosphonic acids and organophosphonic acids are: 3-aminopropylphosphonic acid, 4-methoxyphenylphosphonic acid, benzylphosphonic acid, butylphosphonic acid, carboxyethylphosphonic acid, diphenylphosphonic acid, dodecylphosphonic acid, ethylene diphosphonic acid, heptadecanylphosphonic acid, methylbenzylphosphonic acid, naphthylmethylphosphonic acid, octadecylphosphonic acid, octylphosphonic acid, pentylphosphonic acid, methylphenylphosphonic acid, phenylphosphonic acid, styrenephosphonic acid, dodecyl bis-1,12-phosphonic acid, poly(ethylene glycol)phosphonic acid, and mixtures thereof.

[0029] Phosphorous acid may comprise a mixture of: (a) phosphoric acid; and (b) organophosphonic acid and / or organophosphonic acid. The resulting phosphorylated epoxy resin comprises a mixture of reaction products formed from reactants, said reactants comprising: (i) a polyepoxide; (ii) phosphoric acid; and (iii) organophosphonic acid and / or organophosphonic acid. It is understood that such a mixture of reaction products may comprise a phosphorylated epoxy resin wherein the phosphorylation portion is derived solely from phosphoric acid, a phosphorylated epoxy resin wherein the phosphorylation portion is derived solely from organophosphonic acid and / or organophosphonic acid, and / or a phosphorylated epoxy resin wherein the phosphorylation portion is derived solely from phosphoric acid and / or organophosphonic acid and / or organophosphonic acid. The relative amounts of the reacting polyepoxide and phosphoric acid are: for each amount of epoxy, there may be 0.1 to 0.8 moles of phosphoric acid and 0.01 to 0.4 moles of organophosphonic acid and / or organophosphonic acid, wherein the molar ratio of phosphoric acid to organophosphonic acid and / or organophosphonic acid is in the range of 1:0.01 to 0.5. Based on the resin solid, the acid value of phosphorylated epoxy resin can be from 10 to 60, such as 15 to 50.

[0030] When dispersing phosphorylated epoxy resins in a water-based continuous medium, neutralization with an alkali is performed. Suitable alkalis include both organic and inorganic bases. Illustrative examples of suitable alkalis are ammonia, monoalkylamines, dialkylamines, or trialkylamines, such as ethylamine, propylamine, dimethylamine, dibutylamine, and cyclohexylamine; monoalkylolamines, dialkylolamines, or trialkylolamines, such as ethanolamine, diethanolamine, triethanolamine, propanolamine, isopropanolamine, diisopropanolamine, dimethylethanolamine, and diethylethanolamine; and morpholine, such as N-methylmorpholine or N-ethylmorpholine. The neutralization percentage is determined to impart water dispersibility and electrophoretic properties to the resin. Typically, the resin is at least partially neutralized by 20% to 200%, 40% to 150%, or 60% to 120%.

[0031] According to this disclosure, based on the total weight of the resin solids in the electrodepositable coating composition, the film-forming polymer containing anionic salt groups may be present in the anionic electrodepositable coating composition in an amount of at least 50% by weight, such as at least 55% by weight, such as at least 60% by weight, and may be present in an amount not exceeding 90% by weight, such as not exceeding 80% by weight, such as not exceeding 75% by weight. Based on the total weight of the resin solids in the electrodepositable coating composition, the film-forming polymer containing anionic salt groups may be present in the anionic electrodepositable coating composition in an amount of 50% to 90%, such as 55% to 80%, such as 60% to 75%. As used herein, "resin solids" includes the film-forming polymer containing anionic salt groups, the curing agent, and any other water-dispersible uncolored components present in the electrodepositable coating composition.

[0032] According to this disclosure, the film-forming binder of the anionic electrodepositable coating composition of this disclosure may further include a curing agent. The curing agent may react with reactive groups (such as active hydrogen groups) of the film-forming polymer containing anionic salt groups to achieve curing of the coating composition to form a coating. As used herein, the terms “cured,” “cured,” or similar terms used in conjunction with the coating compositions described herein mean that at least a portion of the components forming the coating composition is crosslinked to form a coating. Furthermore, curing of the coating composition refers to subjecting the composition to curing conditions (e.g., elevated temperatures) that cause the reactive functional groups of the components of the coating composition to react, resulting in crosslinking of the components of the composition and the formation of a coating that is at least partially cured. Non-limiting examples of suitable curing agents are at least partially blocked polyisocyanates, amino plastic resins, and phenolic plastic resins, such as phenol-formaldehyde condensates, containing their allyl ether derivatives.

[0033] According to this disclosure, the film-forming binder component of the electrodepositable coating composition may further include a curing agent. Current agents may include, for example, at least partially blocked polyisocyanates, amino plastic resins, phenolic resins, or any combination thereof.

[0034] Suitable at least partially blocked polyisocyanates include aliphatic polyisocyanates, aromatic polyisocyanates, and mixtures thereof. Curing agents may include at least partially blocked aliphatic polyisocyanates. For example, suitable at least partially blocked aliphatic polyisocyanates include: fully blocked aliphatic polyisocyanates, as described in column 1, lines 57 through 3, lines 15 of U.S. Patent No. 3,984,299, this portion of which is incorporated herein by reference; or partially blocked aliphatic polyisocyanates that react with the polymer backbone, as described in column 2, lines 65 through 4, lines 30 of U.S. Patent No. 3,947,338, this portion of which is also incorporated herein by reference. “Blocked” means that the isocyanate groups have reacted with the compound such that the resulting blocked isocyanate groups are stable to active hydrogen at ambient temperatures but react with active hydrogen in the film-forming polymer at elevated temperatures (e.g., between 90°C and 200°C). Polyisocyanate curing agents can be fully closed polyisocyanates with virtually no free isocyanate groups.

[0035] Polyisocyanate curing agents may include diisocyanates, higher functional polyisocyanates, or combinations thereof. For example, polyisocyanate curing agents may include aliphatic polyisocyanates and / or aromatic polyisocyanates. Aliphatic polyisocyanates may comprise (i) alkylene isocyanates, such as trimethylene diisocyanate, tetramethylene diisocyanate, pentamethylene diisocyanate, hexamethylene diisocyanate (“HDI”), 1,2-propylene diisocyanate, 1,2-butene diisocyanate, 2,3-butene diisocyanate, 1,3-butene diisocyanate, ethylene diisocyanate, and butylene diisocyanate, and (ii) cycloalkylene isocyanates, such as 1,3-cyclopentane diisocyanate, 1,4-cyclohexane diisocyanate, 1,2-cyclohexane diisocyanate, isophorone diisocyanate, methylene bis(4-cyclohexyl) isocyanate (“HMDI”), and cyclotrimers of 1,6-hexamethylene diisocyanate (also known as isocyanurate trimers of HDI, which can be obtained from Covestro). AG) commercially available) and m-tetramethylxylene diisocyanate (can be obtained) (Available commercially from Allnex (SA)). Aromatic polyisocyanates may comprise (i) arylene isocyanates, such as m-phenylene diisocyanate, p-phenylene diisocyanate, 1,5-naphthalene diisocyanate and 1,4-naphthalene diisocyanate, and (ii) arylene alkyl isocyanates, such as 4,4'-diphenylmethane (“MDI”), 2,4-methylphenylene diisocyanate or 2,6-methylphenylene diisocyanate (“TDI”) or mixtures thereof, 4,4-toluidine diisocyanate and xylene diisocyanate. Triisocyanates, such as triphenylmethane-4,4',4”-triisocyanate, 1,3,5-triisocyanatobenzene, and 2,4,6-triisocyanatotoluene, can also be used; tetraisocyanates, such as 4,4'-diphenyldimethylmethane-2,2',5,5'-tetraisocyanate; and polymeric polyisocyanates, such as methyl phenylene diisocyanate dimers and trimers. The curing agent may include blocked polyisocyanates selected from polymeric polyisocyanates (such as polymeric HDI, polymeric MDI, polymeric isophorone diisocyanate, etc.). The curing agent may also include blocked trimers of hexamethylene diisocyanate, which can be Desmodur Available commercially from Covestro AG. Mixtures of polyisocyanate curing agents can also be used.

[0036] The polyisocyanate curing agent may be at least partially blocked by at least one blocking agent selected from the following: 1,2-alkanediol, such as 1,2-propanediol; 1,3-alkanediol, such as 1,3-butanediol; benzyl alcohol, such as benzyl alcohol; allyl alcohol, such as allyl alcohol; caprolactam; dialkylamine, such as dibutylamine; and mixtures thereof. The polyisocyanate curing agent may be at least partially blocked by at least one 1,2-alkanediol having three or more carbon atoms (e.g., 1,2-butanediol).

[0037] Other suitable blocking agents include aliphatic, alicyclic, or aromatic alkyl monohydric alcohols or phenolic compounds, including, for example, lower aliphatic alcohols such as methanol, ethanol, and n-butanol; alicyclic alcohols such as cyclohexanol; aromatic alkyl alcohols such as benzyl alcohol and methylphenylmethanol; and phenolic compounds such as phenol itself and substituted phenols such as cresol and nitrophenol, wherein the substituents do not affect the coating operation. Glycol ethers and glycol amines can also be used as blocking 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 ketone oxime, acetone oxime, and cyclohexanone oxime.

[0038] The blocking agent may also include α-hydroxyamides, esters, or thioesters. As used herein, the term "α-hydroxyamide" refers to an organic compound having at least one α-hydroxyamide moiety comprising a hydroxyl functional group covalently bonded to the α-carbon of an amide group. As used herein, the term "α-hydroxy ester" refers to an organic compound having at least one α-hydroxy ester moiety comprising a hydroxyl functional group covalently bonded to the α-carbon of an ester group. As used herein, the term "α-hydroxy thioester" refers to an organic compound having at least one α-hydroxy thioester moiety comprising a hydroxyl functional group covalently bonded to the α-carbon of a thioester group. Blocking agents comprising α-hydroxyamides, esters, or thioesters may include compounds of structure (I):

[0039]

[0040] Where X represents N(R2), O, or S; n ranges from 1 to 4; when n = 1 and X = N(R2), R represents hydrogen, Cl, or C. 10 Alkyl, aryl, polyether, polyester, polyurethane, hydroxyalkyl, or thioalkyl; when n = 1 and X = O or S, R is C1 to C1. 10 Alkyl, aryl, polyether, polyester, polyurethane, hydroxyalkyl, or thioalkyl; when n = 2 to 4, R is a polyvalent C1 to C2 group. 10 Alkyl, polyaryl, polyether, polyester, polyurethane; each R1 is independently hydrogen, C1 to C1. 10 Alkyl, aryl, or alicyclic group; each R2 is independently hydrogen, C1 to C2. 10 Alkyl, aryl, alicyclic, hydroxyalkyl, or thioalkyl groups; and R and R2 together can form an alicyclic heterocyclic structure. Alicyclic heterocyclic structures can include, for example, morpholine, piperidine, or pyrrolidine. It should be noted that if X is N(R2), then R can only be hydrogen. Specific examples of suitable alph-hydroxyamides, esters, or thioester blocking agents are described in paragraphs

[0012] to

[0026] of International Publication WO 2018 / 148306A1, the referenced portion of which is incorporated herein by reference.

[0041] Curing agents may include amino plastic resins. Amino plastic resins are condensation products of aldehydes and substances carrying amino or amide groups. Condensation products obtained by reacting alcohols and aldehydes with melamine, urea, or benzoguanidine can be used. However, condensation products of other amines and amides may also be used, such as aldehyde condensates of alkyl and aryl-substituted derivatives of triazine, diazine, triazole, guanidine, guanidine, and alkyl and aryl-substituted ureas and alkyl and aryl-substituted melamines. Some examples of such compounds are N,N'-dimethylurea, phenylurea, dicyandiamide, formaguanamine, acetoguanamine, ammeline, 2-chloro-4,6-diamino-1,3,5-triazine, 6-methyl-2,4-diamino-1,3,5-triazine, 3,5-diaminotriazole, triaminopyrimidine, 2-mercapto-4,6-diaminopyrimidine, and 3,4,6-tris(ethylamino)-1,3,5-triazine. Suitable aldehydes include formaldehyde, acetaldehyde, crotonaldehyde, acrolein, benzaldehyde, furfural, and glyoxal.

[0042] Amino plastic resins may contain hydroxymethyl groups or similar alkyl alcohol groups, and at least a portion of these alkyl alcohol groups may be etherified by reaction with an alcohol to provide a resin soluble in organic solvents. For this purpose, any monohydric alcohol may be used, including alcohols such as methanol, ethanol, propanol, butanol, pentanol, hexanol, heptanol, and others, as well as benzyl alcohol and other aromatic alcohols, cyclic alcohols such as cyclohexanol, monoethers of ethylene glycol such as cellosolves and carbitols, and halogenated or other substituted alcohols such as 3-chloropropanol and butoxyethanol.

[0043] A non-limiting example of commercially available amino plastic resins is the trademarked product of Allnex Belgium SA / NV. (such as CYMEL 1130 and 1156) and trademarked products from INEOS Melamines. Commercially available amino plastic resins (such as RESIMENE 750 and 753). Examples of suitable amino plastic resins are also included in the amino plastic resins described in column 16, line 3 through column 17, line 47 of U.S. Patent No. 3,937,679, this portion of which is hereby incorporated by reference. As disclosed in the foregoing portion of the '679 patent, amino plastics can be used in combination with hydroxymethylphenol ethers.

[0044] Phenolic resins are formed by the condensation of aldehydes and phenols. Suitable aldehydes include formaldehyde and acetaldehyde. Methylene releasers and aldehyde releasers (such as paraformaldehyde and hexamethylenetetramine) can also be used as aldehyde agents. Various phenols can be used, such as phenol itself, cresol, or substituted phenols, wherein a hydrocarbon group having a straight-chain, branched, or cyclic structure replaces hydrogen in an aromatic ring. Mixtures of these phenols can also be used. Some specific examples of suitable phenols are p-phenylphenol, p-tert-butylphenol, p-tert-pentylphenol, cyclopentylphenol, and unsaturated hydrocarbon-substituted phenols, such as monobutenylphenol containing a butenyl group at the ortho, meta, or para position, wherein the double bond appears at various positions in the hydrocarbon chain.

[0045] The amino and phenolic plastic resins described above are described in column 6, line 20 through column 7, line 12 of U.S. Patent No. 4,812,215, the referenced portion of which is incorporated herein by reference.

[0046] The curing agent may optionally include high molecular weight volatile groups. As used herein, the term "high molecular weight volatile groups" refers to blocking agents and other organic byproducts that are generated and volatilized during the curing reaction of the coating composition, the coating composition having a molecular weight of at least 70 g / mol, such as at least 125 g / mol, such as at least 160 g / mol, such as at least 195 g / mol, such as at least 400 g / mol, such as at least 700 g / mol, such as at least 1000 g / mol or higher, and may be in the range of 70 to 1,000 g / mol, such as 160 to 1,000 g / mol, such as 195 to 1,000 g / mol, such as 400 to 1,000 g / mol, such as 700 to 1,000 g / mol. For example, organic byproducts may include alcohol byproducts generated from the reaction of the film-forming polymer and the curing agent of amino or phenolic plastics, and the sealing agent may contain organic compounds, including alcohols, for use with isocyanate groups of the polyisocyanate in the uncoated composition during curing of the coating composition. For clarity, the high molecular weight volatile groups are covalently bonded to the curing agent prior to curing, and any organic solvents that may be present in the coating composition are explicitly excluded. During curing, the ratio of pigment to binder in the cured film may increase relative to the ratio of uncured pigment to binder deposited in the coating composition, due to the loss of higher quality sealing agent and other organic matter derived from the curing agent volatilized during curing. Based on the total weight of the film-forming binder, the high molecular weight volatile groups may account for 5% to 50% by weight of the film-forming binder, such as 7% to 45% by weight, such as 9% to 40% by weight, such as 11% to 35% by weight, such as 13% to 30% by weight. Based on the total weight of the film-forming adhesive before and after curing, high molecular weight volatile groups and other low molecular weight volatile organic compounds generated during curing, such as low molecular weight sealants and organic byproducts generated during curing, may be present in an amount such that the relative weight loss of the film-forming adhesive deposited on the substrate relative to the weight of the cured film-forming adhesive is 5% to 50% by weight, such as 7% to 45% by weight, such as 9% to 40% by weight, such as 11% to 35% by weight, such as 13% to 30% by weight.

[0047] Based on the total weight of the resin solids in the electrodepositable coating composition, the curing agent may be present in the anionic electrodepositable coating composition in an amount of at least 10% by weight, such as at least 20% by weight, such as at least 25% by weight, and may be present in an amount not exceeding 50% by weight, such as not exceeding 45% by weight, such as not exceeding 40% by weight. Based on the total weight of the resin solids in the electrodepositable coating composition, the curing agent may be present in the anionic electrodepositable coating composition in an amount of from 10% by weight to 50% by weight, such as from 20% by weight to 45% by weight, such as from 25% by weight to 40% by weight.

[0048] In addition to the film-forming polymers and curing agents containing anionic salt groups described above, the anionic electrodepositable coating compositions according to this disclosure may optionally include one or more additional components.

[0049] According to this disclosure, electrodepositable coating compositions may optionally include a catalyst for catalyzing the reaction between the curing agent and the polymer. Examples of catalysts suitable for anionic electrodepositable coating compositions include latent acid catalysts, specific examples of which are identified at

[0031] in WO 2007 / 118024 and contain, but are not limited to, ammonium hexafluoroantimonate, quaternary salts of SbF6 (e.g., XC-7231), tertiary amine salts of SbF6 (e.g., XC-7231), and SbF6 tertiary amine salts (e.g., XC-9223), Zn salts of trifluoromethanesulfonic acid (e.g., A202 and A218), quaternary salts of trifluoromethanesulfonic acid (e.g., A202 and A218), and trifluoromethanesulfonic acid quaternary salts (e.g., XC-A230) and diethylamine salts of trifluoromethanesulfonic acid (e.g., XC-A230) and trifluoromethanesulfonic acid (e.g., A233 (all commercially available from King Industries) and / or mixtures thereof. Latent acid catalysts can be formed by preparing derivatives of acid catalysts such as p-toluenesulfonic acid (pTSA) or other sulfonic acids. For example, a well-known group of blocked acid catalysts are amine salts of aromatic sulfonic acids, such as pyridinium p-toluenesulfonic acid. These sulfonates are less active than free acids in promoting crosslinking. During curing, the catalyst can be activated by heating.

[0050] According to this disclosure, the electrodeposable coating composition may include other optional components, such as pigment compositions and various additives, and, if desired, fillers, plasticizers, antioxidants, biocides, UV light absorbers and stabilizers, hindered amine light stabilizers, defoamers, fungicides, dispersants, flow control agents, surfactants, wetting agents, or combinations thereof. Alternatively, the electrodeposable coating composition may be completely free of any optional components, i.e., the optional components are not present in the electrodeposable coating composition. The pigment composition may include, for example, iron oxide, lead oxide, strontium chromate, carbon black, coal powder, titanium dioxide, talc, barium sulfate, and colored pigments such as cadmium yellow, cadmium red, and chrome yellow. The pigment content of the dispersion may be expressed as the weight ratio of pigment to resin, and when pigments are used, the pigment content may be in the range of 0.03 to 0.6. Based on the total weight of the resin solids in the electrodeposable coating composition, the other additives mentioned above may be present in the electrodeposable coating composition in an amount from 0.01% to 3% by weight.

[0051] The electrodepositable coating composition may optionally further include a corrosion inhibitor. The corrosion inhibitor may include azoles, calcium ion-exchanged silica, or any combination thereof.

[0052] Non-limiting examples of suitable calcium ion-exchanged silica are commercially available from WRGrace & Co. as SHIELDEX AC3 and / or SHIELDEX C303.

[0053] Non-limiting examples of suitable azoles include benzotriazole, 5-methylbenzotriazole, 2-aminothiazole, and their salts.

[0054] Based on the total weight of the electrodeposable coating composition, a corrosion inhibitor (if any) may be present in the anionic electrodeposable coating composition in an amount of at least 0.001 wt%, such as at least 5 wt%. Based on the total weight of the electrodeposable coating composition, a corrosion inhibitor (if any) may be present in the anionic electrodeposable coating composition in an amount of no more than 25 wt%, such as no more than 15 wt%, such as no more than 10 wt%. Based on the total weight of the electrodeposable coating composition, a corrosion inhibitor (if any) may be present in the anionic electrodeposable coating composition in an amount of 0.001 wt% to 25 wt%, such as 0.001 wt% to 15 wt%, such as 0.001 wt% to 10 wt%, such as 5 wt% to 25 wt%, such as 5 wt% to 15 wt%, such as 5 wt% to 10 wt%.

[0055] Alternatively, the electrodepositable coating composition may be substantially free of, substantially free of, or completely free of corrosion inhibitors.

[0056] According to this disclosure, the electrodepositable coating composition may include water and / or one or more organic solvents. Based on the total weight of the electrodepositable coating composition, water may be present, for example, in an amount from 40% to 90% by weight, such as 50% to 75% by weight. Examples of suitable organic solvents include oxidizing organic solvents such as monoalkyl ethers of ethylene glycol, diethylene glycol, propylene glycol, and dipropylene glycol containing 1 to 10 carbon atoms in the alkyl group, such as monoethyl ethers and monobutyl ethers of these glycols. Examples of other solvents at least partially miscible with water include alcohols such as ethanol, isopropanol, butanol, and diacetone alcohol. If used, the organic solvent may generally be present in an amount less than 10% by weight, such as less than 5% by weight, based on the total weight of the electrodepositable coating composition. The electrodepositable coating composition may be specifically provided in the form of a dispersion, such as an aqueous dispersion.

[0057] According to this disclosure, based on the total weight of the electrodeposable coating composition, the total solids content of the electrodeposable coating composition can be at least 1% by weight, such as at least 5% by weight, and can not exceed 50% by weight, such as not exceeding 40% by weight, such as not exceeding 20% ​​by weight. Based on the total weight of the electrodeposable coating composition, the total solids content of the electrodeposable coating composition can be from 1% by weight to 50% by weight, such as from 5% by weight to 40% by weight, such as from 5% by weight to 20% by weight. As used herein, “total solids” refers to the non-volatile contents of the electrodeposable coating composition, i.e., materials that will not volatilize when heated to 110°C for 15 minutes.

[0058] Non-electrodepositable coating compositions

[0059] According to this disclosure, the system for coating a metal substrate further includes a non-electrodepositable coating composition comprising a corrosion inhibitor of azole.

[0060] Non-electrodepositable coating compositions include curable organic film-forming binders.

[0061] As used herein, the term "curable" and similar terms refer to compositions that undergo an irreversible "curing" reaction, such as when the components of the composition react with each other and the polymer chains of the polymer components are linked together by covalent bonds. This property is often associated with cross-linking reactions of the composition components, for example, caused by heat or radiation. See Hawley, Gessner G., The Condensed Chemical Dictionary, 9th edition, p. 856; Surface Coatings, Vol. 2, Oil and Colour Chemists' Association, Australia, TAFE Educational Books (1974). Curing or cross-linking reactions can also occur under ambient conditions. Ambient conditions mean that the coating undergoes a thermosetting reaction without the aid of heat or other energy, for example, without baking in an oven, without the use of forced air, etc. Ambient temperatures typically range from 60 to 90℉ (15.6 to 32.2°C), such as typical room temperature, 72℉ (22.2°C). Once cured or cross-linked, thermosetting resins will not melt when heat is applied and will not dissolve in solvents.

[0062] Organic film-forming adhesives may include: (a) a resin component comprising reactive functional groups; and (b) a curing agent component comprising functional groups that react with the functional groups in the resin component (a), although the film-forming adhesive component may also contain a resin that crosslinks with itself rather than with another curing agent (i.e., self-crosslinking).

[0063] The resin component (a) used in the organic film-forming adhesive component of the curable film-forming composition disclosed herein may include one or more of the following: acrylic polymers, polyesters, polyurethanes, polyamides, polyethers, polysulfides, polysulfides, polythioesters, polythiols, polyolefins, polyols, polysilanes, polysiloxanes, fluoropolymers, polycarbonates, and epoxy resins. Typically, these compounds, which do not need to be polymers, can be prepared by any method known to those skilled in the art. The functional groups on the film-forming adhesive may include at least one of the following: carboxylic acid groups, amino groups, epoxide groups, hydroxyl groups, thiol groups, urethane groups, amide groups, urea groups, (meth)acrylate groups, styrene groups, vinyl groups, allyl groups, aldehyde groups, acetoacetate groups, hydrazide groups, cyclic carbonates, and maleic acid or anhydride groups. The functional groups on the film-forming adhesive are selected to react with or self-crosslink with the functional groups on the curing agent (b).

[0064] Suitable acrylic compounds comprise one or more alkyl esters of acrylic acid or methacrylic acid, optionally copolymers with one or more other polymerizable olefinically unsaturated monomers. Useful alkyl esters of acrylic acid or methacrylic acid comprise aliphatic alkyl esters containing 1 to 30 carbon atoms in the alkyl group, and typically 4 to 18 carbon atoms. Non-limiting examples include methyl methacrylate, ethyl methacrylate, butyl methacrylate, ethyl acrylate, butyl acrylate, and 2-ethylhexyl acrylate. Other suitable copolymerizable olefinically unsaturated monomers comprise vinyl aromatic compounds such as styrene and vinyltoluene; nitriles such as acrylonitrile and methacrylonitrile; vinyl and vinylidene halides such as vinyl chloride and vinylidene fluoride; and vinyl esters such as vinyl acetate.

[0065] Acrylic copolymers may contain hydroxyl functional groups, which are typically incorporated into the polymer by including one or more hydroxyl functional monomers in the reactants used to generate the copolymer. Useful hydroxyl functional monomers include hydroxyalkyl acrylates and hydroxyalkyl methacrylates, typically having 2 to 4 carbon atoms in the hydroxyalkyl group, such as hydroxyethyl acrylate, hydroxypropyl acrylate, 4-hydroxybutyl acrylate, caprolactone, and hydroxyalkyl acrylate hydroxyl functional adducts and their corresponding methacrylates, as well as β-hydroxy ester functional monomers described below. Acrylic polymers can also be prepared using N-(alkoxymethyl)acrylamide and N-(alkoxymethyl)methacrylamide.

[0066] β-hydroxy ester functional monomers can be prepared from olefinically unsaturated epoxy functional monomers and carboxylic acids having about 13 to about 20 carbon atoms, or from olefinically unsaturated acid functional monomers and epoxy compounds containing at least 5 carbon atoms that cannot be polymerized with olefinically unsaturated acid functional monomers.

[0067] Useful olefinically unsaturated epoxy functional monomers for preparing β-hydroxy ester functional monomers include glycidyl acrylate, glycidyl methacrylate, allyl glycidyl ether, methyl allyl glycidyl ether, olefinically unsaturated monoisocyanates and hydroxyl-functionalized monoepoxides, such as 1:1 (molar) adducts of glycidyl acrylate, and polymerizable polycarboxylic acids such as glycidyl maleic acid. (Note: These epoxy functional monomers can also be used to prepare epoxy-functionalized acrylic polymers.) Examples of carboxylic acids include saturated monocarboxylic acids such as isostearic acid and aromatic unsaturated carboxylic acids.

[0068] Useful olefinically unsaturated acid functional monomers for the preparation of β-hydroxy ester functional monomers include carboxylic acids such as acrylic acid, methacrylic acid, and crotonic acid; dicarboxylic acids such as itaconic acid, maleic acid, and fumaric acid; and monoesters of dicarboxylic acids such as monobutyl maleate and monobutyl itaconic acid. The olefinically unsaturated acid functional monomers and epoxides typically react in a 1:1 equivalence ratio. The epoxides do not contain olefinic unsaturation that would participate in radical-initiated polymerization with the unsaturated acid functional monomers. Available epoxides include 1,2-pentene oxide, styrene oxide, and glycidyl esters or glycidyl ethers, typically containing 8 to 30 carbon atoms, such as butyl glycidyl ether, octyl glycidyl ether, phenyl glycidyl ether, and p-(tert-butyl)phenyl glycidyl ether. Certain glycidyl esters contain the following structures:

[0069]

[0070] R1 is a hydrocarbon group containing about 4 to about 26 carbon atoms. Typically, R is a branched hydrocarbon group having about 8 to about 10 carbon atoms, such as neopentanoate, neoheptanoate, or neodecanoate. Suitable glycidyl carboxylate esters include VERSATICACID 911 and CARDURA E, both of which are commercially available from Shell Chemical Co.

[0071] The urethane functional group can be incorporated into the acrylic polymer by copolymerizing an acrylic monomer with a urethane-functionalized vinyl monomer, such as a urethane-functionalized alkyl ester of methacrylic acid, or by reacting a hydroxyl-functionalized acrylic polymer with a low molecular weight urethane-functionalized material, such as that derived from an alcohol or glycol ether, via a transcarbamic reaction. In this reaction, the low molecular weight urethane-functionalized material derived from the alcohol or glycol ether reacts with the hydroxyl group of the acrylic polyol to produce a urethane-functionalized acrylic polymer and the original alcohol or glycol ether. The low molecular weight urethane-functionalized material derived from the alcohol or glycol ether can be prepared by reacting the alcohol or glycol ether with urea in the presence of a catalyst. Suitable alcohols include lower molecular weight aliphatic alcohols, alicyclic alcohols, and aromatic alcohols, such as methanol, ethanol, propanol, butanol, cyclohexanol, 2-ethylhexanol, and 3-methylbutanol. Suitable glycol ethers include ethylene glycol methyl ether and propylene glycol methyl ether. Propylene glycol methyl ether and methanol are the most commonly used. Other urethane-functionalized monomers known to those skilled in the art can also be used.

[0072] Amide functional groups can be introduced into acrylic polymers by using suitable functional monomers in the preparation of the polymer or by converting other functional groups into amide groups using techniques known to those skilled in the art. Similarly, other functional groups can be incorporated as desired by using suitable functional monomers (if available) or by conversion reactions (as required).

[0073] Acrylic polymers can be prepared by aqueous emulsion polymerization and used directly in the preparation of aqueous coating compositions, or they can be prepared by organic solution polymerization for solvent-based compositions. When prepared by organic solution polymerization with groups capable of forming salts, such as acid or amine groups, the polymer can be dispersed in an aqueous medium after neutralizing these groups with a base or acid. Generally, any method known to those skilled in the art for producing such polymers using monomer amounts recognized in the art can be used.

[0074] The resin component (a) in the film-forming binder component of the curable film-forming composition may include alkyd resins or polyesters. Such polymers can be prepared in a known manner by the condensation of polyols and polycarboxylic acids. Suitable polyols include, but are not limited to, ethylene glycol, propylene glycol, butanediol, 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 mentioned above, functional equivalents of acids, such as acid anhydrides or lower alkyl esters of acids, such as methyl esters, may be used where present. In cases where it is desired to produce an air-dried alkyd resin, suitable drying oil fatty acids may be used, and these oil fatty acids may include, for example, those derived from linseed oil, soybean oil, rosin oil, dehydrated castor oil, or tung oil.

[0075] Similarly, polyamides can be prepared using polybasic acids and polyamines. Suitable polybasic acids include those listed above, and polyamines can include, for example, ethylenediamine, 1,2-diaminopropane, 1,4-diaminobutane, 1,3-diaminopentane, 1,6-diaminohexane, 2-methyl-1,5-pentanediamine, 2,5-diamino-2,5-dimethylhexane, 2,2,4- and / or 2,4,4-trimethyl-1,6-diaminohexane, 1,11-diaminoundecane, 1,12-diaminododecane, 1,3-cyclohexanediamine and / or 1,4-cyclohexanediamine, 1-amino-3,3-diaminopropane, 1,2-diaminopropane, 1,4-diaminopropane, 1,4-diaminopropane, 1,4-diaminopropane, 1,4-diaminopropane, 1,3-diaminopropane, 1,4 ... 5-Trimethyl-5-aminomethyl-cyclohexane, 2,4-and / or 2,6-hexahydrotoluene diamine, 2,4'-and / or 4,4'-diamino-dicyclohexylmethane and 3,3'-dialkyl-4,4'-diamino-dicyclohexylmethane (such as 3,3'-dimethyl-4,4'-diamino-dicyclohexylmethane and 3,3'-diethyl-4,4'-diamino-dicyclohexylmethane), 2,4-diaminotoluene and / or 2,6-diaminotoluene, and 2,4'-diaminobiphenylmethane and / or 4,4'-diaminobiphenylmethane.

[0076] Carbamate functional groups can be incorporated into polyesters or polyamides by first forming urethane hydroxyalkyl esters, which can react with polyacids and polyols / polyamines used to form the polyesters or polyamides. The urethane hydroxyalkyl esters condense with acid functional groups on the polymer to generate terminal carbamate functional groups. Carbamate functional groups can also be incorporated into polyesters by reacting terminal hydroxyl groups on the polyester with low molecular weight carbamate functional materials via a transcarbamylation process similar to that described above for incorporating carbamate groups into acrylic polymers, or by reacting isocyanate with hydroxyl-functionalized polyesters.

[0077] Other functional groups, such as amines, amides, thiols, ureas, or other functional groups listed above, can be incorporated into polyamides, polyesters, or alkyd resins, depending on the desired functional group, using suitable functional reactants (if available) or conversion reactions (if required). Such techniques are known to those skilled in the art.

[0078] Polyurethane can also be used as a resin component (a) in the film-forming binder component of curable film-forming compositions. Polyurethanes that can be used contain polymeric polyols, which are typically prepared by reacting polyester polyols or acrylic polyols (such as those described above) with polyisocyanates, such that the OH / NCO equivalent ratio is greater than 1:1, resulting in the presence of free hydroxyl groups in the product. The organic polyisocyanate used to prepare the polyurethane polyol can be an aliphatic or aromatic polyisocyanate or a mixture of both. Diisocyanates are commonly used, although higher polyisocyanates can be used instead of diisocyanates or in combination with diisocyanates. Examples of suitable aromatic diisocyanates are 4,4'-diphenylmethane diisocyanate and toluene diisocyanate. Examples of suitable aliphatic diisocyanates are linear aliphatic diisocyanates, such as 1,6-hexamethylene diisocyanate. Additionally, alicyclic diisocyanates can be used. Examples include isophorone diisocyanate and 4,4'-methylene-bis-(cyclohexyl isocyanate). Suitable examples of advanced polyisocyanates are 1,2,4-phenyltriisocyanate polymethylene polyphenylisocyanate, and isocyanate trimers based on 1,6-hexamethylene diisocyanate or isophorone diisocyanate. Similar to polyesters, polyurethanes can be prepared from unreacted carboxylic acid groups, which allow dispersion in aqueous media upon neutralization with a base, such as an amine.

[0079] Terminal and / or side-group urethane functional groups can be incorporated into polyurethanes by reacting polyisocyanates with polymeric polyols containing terminal / side-group urethane groups. Alternatively, urethane functional groups can be incorporated into polyurethanes by reacting polyisocyanates with polyols and urethane hydroxyalkyl esters or isocyanates as separate reactants. Urethane functional groups can also be incorporated into polyurethanes by reacting hydroxyl-functionalized polyurethanes with low molecular weight urethane functional materials through a transcarbamylation process similar to that described above for incorporating urethane groups into acrylic polymers. Additionally, isocyanate-functionalized polyurethanes can be reacted with urethane hydroxyalkyl esters to produce urethane-functionalized polyurethanes.

[0080] Other functional groups, such as amides, thiols, ureas, or other functional groups listed above, can be incorporated into polyurethanes as desired, using suitable functional reactants (if available) or conversion reactions (if required), to produce the desired functional groups. Such techniques are known to those skilled in the art.

[0081] Examples of polyether polyols are polyalkylene ether polyols, which include those having the following structural formulas:

[0082] (i)

[0083]

[0084] Or (ii)

[0085]

[0086] The substituent R2 is hydrogen or a lower alkyl group containing 1 to 5 carbon atoms, and includes mixed substituents. n is typically 2 to 6, and m is 8 to 100 or higher. It includes poly(oxytetramethylene) glycol, poly(oxytetraethylene) glycol, poly(oxy-1,2-propylene) glycol, and poly(oxy-1,2-butene) glycol.

[0087] Also useful are polyether polyols formed by the alkoxylation of various polyols, such as glycols like ethylene glycol, 1,6-hexanediol, bisphenol A, etc., or other higher polyols like trimethylolpropane, pentaerythritol, etc. Polyols with higher functional groups that can be used as indicated can be prepared, for example, by the alkoxylation of compounds such as sucrose or sorbitol. A common alkoxylation method involves reacting the polyol with an epoxide, such as propylene or ethylene oxide, in the presence of an acidic or basic catalyst. Specific polyethers include those marketed under the trade names TERATHANE and TERACOL (available from The Lycra Company) and POLYMEG (available from LyondellBasell).

[0088] Carbamate functional groups can be incorporated into polyethers via transcarbamyl reactions. Other functional groups, such as acids, amines, epoxides, amides, thiols, and ureas, can be incorporated into polyethers to produce the desired functional groups, depending on the desired use of suitable functional reactants (if available) or conversion reactions (if required). Examples of suitable amine-functionalized polyethers include those sold under the trade name JEFFAMINE, such as JEFFAMINE D2000, a polyether-functionalized diamine available from Huntsman Corporation.

[0089] Suitable epoxy resin functional polymers used as resin component (a) may comprise polyepoxides that are chain-extended by reacting the polyepoxide with a polyhydroxy material selected from materials containing alcohol hydroxyl groups and phenol hydroxyl groups to extend the chain or to construct the molecular weight of the polyepoxide.

[0090] Chain-extended polyepoxides are typically prepared by reacting the polyepoxide with a polyhydroxyl-containing material, either in the presence of pure organic solvents (such as ketones, including methyl isobutyl ketone and methyl pentyl ketone), aromatic compounds (such as toluene and xylene), and glycol ethers (such as dimethyl ether of diethylene glycol). The reaction is usually carried out at temperatures between 80°C and 160°C for 30 to 180 minutes until an epoxy-containing resin product is obtained.

[0091] The equivalence ratio of the reactants, i.e., epoxy resin: polyhydroxyl-containing material, is typically from about 1.00:0.75 to 1.00:2.00. Those skilled in the art will understand that when reacting with polyhydroxyl-containing materials, the chain-extended polyepoxide will lack epoxide functional groups, resulting in an excess of hydroxyl functional groups. The resulting polymer will include hydroxyl functional groups generated from the excess hydroxyl functional groups and hydroxyl functional groups generated from the ring-opening reaction of the epoxide functional groups.

[0092] By definition, polyepoxides have at least two 1,2-epoxy groups. Typically, the epoxide equivalent of polyepoxides can range from 100 to 2000, such as 180 to 500. Epoxides can be saturated or unsaturated, cyclic or acyclic, aliphatic, alicyclic, aromatic, or heterocyclic. They may contain substituents such as halogens, hydroxyl groups, and ether groups.

[0093] Examples of polyepoxides are those having one to two (e.g., more than one and less than two or two) 1,2-epoxy equivalents; that is, polyepoxides having an average of two epoxide groups per molecule. The most commonly used polyepoxides are polyglycidyl ethers of cyclic polyols, such as polyglycidyl ethers of polyphenols like bisphenol A, resorcinol, hydroquinone, benzyl alcohol, phloroglucinol, and catechol; or polyols, such as alicyclic polyols, especially 1,2-cyclohexanediol, 1,4-cyclohexanediol, 2,2-bis(4-hydroxycyclohexyl)propane, 1,1-bis(4-hydroxycyclohexyl)ethane, 2-methyl-1,1-bis(4-hydroxycyclohexyl)propane, 2,2-bis(4-hydroxy-3-tert-butylcyclohexyl)propane, 1,3-bis(hydroxymethyl)cyclohexane, and 1,2-bis(hydroxymethyl)cyclohexane. Examples of aliphatic polyols include trimethylpentanediol and neopentanediol.

[0094] The polyhydroxyl-containing material used for chain extension or increasing the molecular weight of the polyepoxide may additionally be a polymeric polyol, such as any of the polymeric polyols disclosed above. This disclosure may include diglycidyl ethers of epoxy resins such as bisphenol A, bisphenol F, glycerol, phenolic resins, etc. Exemplary suitable polyepoxides are described in column 5, lines 33 to 58 of U.S. Patent No. 4,681,811, the reference portion of which is incorporated herein by reference. Non-limiting examples of suitable commercially available epoxy resins include EPON 828 and EPON 1001, both available from Momentive Corporation, and DEN 431, available from Dow Chemical Co.

[0095] Epoxy-functionalized film-forming polymers can also be acrylic polymers prepared from epoxy-functionalized monomers, such as glycidyl acrylate, glycidyl methacrylate, allyl glycidyl ether, and methyl allyl glycidyl ether. Polyesters, polyurethanes, or polyamides prepared from glycidyl alcohols or glycidylamines, or reacted with epihaloalcohols, are also suitable epoxy-functionalized resins. Epoxide functional groups can be incorporated into the resin by reacting the hydroxyl groups on the resin with epihaloalcohols or dihaloalcohols, such as epichlorohydrin or dichloropropanol, in the presence of a base.

[0096] Non-limiting examples of suitable fluoropolymers include fluoroethylene-alkyl vinyl ether alternating copolymers (such as those described in U.S. Patent No. 4,345,057) available from Asahi Glass Company under the trade name LUMIFLON; fluorinated aliphatic polymer esters commercially available from 3M of St. Paul, Minnesota under the trade name FLUORAD; and perfluorinated hydroxyl-functionalized (meth)acrylate resins.

[0097] Based on the total weight of resin solids in the curable film-forming composition, the amount of resin component (a) in the curable film-forming composition can range from 10 wt% to 90 wt%. For example, based on the total weight of resin solids in the curable film-forming composition, the minimum amount of resin component can be at least 10 wt%, such as at least 20 wt% or at least 30 wt%. The maximum amount of resin can be 90 wt%, such as 80 wt% or 70 wt%. Based on the total weight of resin solids in the curable film-forming composition, the resin component can range from, for example, 20 wt% to 80 wt%, 50 wt% to 90 wt%, 60 wt% to 80 wt%, or 25 wt% to 75 wt%.

[0098] According to this disclosure, the film-forming binder of the coating composition may further include a curing agent. The curing agent can react with reactive groups (such as active hydrogen groups) of the film-forming polymer containing anionic salt groups to achieve curing of the coating composition to form a coating. As used herein, the terms “cured,” “cured,” or similar terms used in conjunction with the coating compositions described herein mean that at least a portion of the components forming the coating composition is crosslinked to form a coating. Furthermore, curing of the coating composition refers to subjecting the composition to curing conditions (e.g., elevated temperatures) that cause the reactive functional groups of the components of the coating composition to react, resulting in crosslinking of the components of the composition and the formation of a coating that is at least partially cured. Non-limiting examples of suitable curing agents are at least partially blocked polyisocyanates, amino plastic resins, and phenolic plastic resins, such as phenol-formaldehyde condensates, containing their allyl ether derivatives.

[0099] According to this disclosure, the film-forming binder component of a non-electrodepositable coating composition may further include a curing agent (b). Suitable curing agents (b) for the film-forming binder component of the coating compositions of this disclosure include amino plastics, polyisocyanates, blocked isocyanates, polyepoxides, β-hydroxyalkylamides, polybasic acids, organometallic acid functional materials, polyamines, polyamides, polysulfides, polythiols, polyolefins such as polyacrylates, polyols, polysilanes, and mixtures of any of the foregoing, and include those known in the art for use with any of these materials. The terms “curing agent,” “crosslinking agent,” and “crosslinker” are used interchangeably herein.

[0100] Useful amino plastics 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.

[0101] While condensation products obtained from the reaction of alcohols and formaldehyde with melamine, urea, or benzoguanidine are most common, condensations with other amines or amides can also be used. Formaldehyde is the most commonly used aldehyde, but other aldehydes such as acetaldehyde, crotonaldehyde, and benzaldehyde can also be used.

[0102] Amino plastics may contain imino and hydroxymethyl groups. In some cases, at least a portion of the hydroxymethyl group may be etherified with an alcohol to modify the curing response. Any monohydric alcohol, such as methanol, ethanol, n-butanol, isobutanol, and hexanol, can be used for this purpose. Non-limiting examples of suitable amino plastic resins are available from Allnex under the trademark CYMEL and from INEOS under the trademark RESIMENE.

[0103] Other suitable crosslinking agents include polyisocyanate crosslinking agents. As used herein, the term "polyisocyanate" is intended to include both closed (or end-capped) polyisocyanates and unclosed polyisocyanates. Polyisocyanates can be aliphatic, aromatic, or mixtures thereof. Although higher polyisocyanates, such as isocyanurates of diisocyanates, are frequently used, diisocyanates can also be used. Isocyanate prepolymers, such as reaction products of polyisocyanates and polyols, can also be used. Mixtures of polyisocyanate crosslinking agents can be used.

[0104] 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-trimethylhexamethylene diisocyanate and 2,4,4-trimethylhexamethylene diisocyanate, 1,6-hexamethylene diisocyanate, tetramethylphenyl diisocyanate, and 4,4'-diphenylmethylene diisocyanate. Furthermore, blocked polyisocyanate prepolymers of various polyols, such as polyester polyols, can also be used.

[0105] Depending on the desired outcome, the isocyanate group can be either capped or uncapped. If the polyisocyanate is to be capped or closed, any suitable aliphatic, alicyclic, or aromatic alkyl monool or phenolic compound known to those skilled in the art can be used as a capping agent for the polyisocyanate. Examples of suitable capping agents include materials that decapsulate at elevated temperatures, such as lower aliphatic alcohols including methanol, ethanol, and n-butanol; alicyclic alcohols such as cyclohexanol; aromatic alkyl alcohols such as benzyl alcohol and methylphenylmethanol; and phenolic compounds such as phenol itself and substituted phenols such as cresol and nitrophenol, wherein the substituents do not affect the coating operation. Glycol ethers can also be used as 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 capping agents include oximes such as methyl ethyl ketone oxime, acetone oxime and cyclohexanone oxime, lactams such as ε-caprolactam, pyrazoles such as dimethylpyrazole and amines such as dibutylamine, butanediolamide and butyl lactic acid amine.

[0106] The crosslinking agent may optionally include high molecular weight volatile groups. These may be the same as those discussed above. Based on the total weight of the organic film-forming adhesive, the high molecular weight volatile groups may account for 5% to 50% by weight of the film-forming adhesive, such as 7% to 45% by weight, 9% to 40% by weight, 11% to 35% by weight, or 13% to 30% by weight. Based on the total weight of the organic film-forming adhesive before and after curing, the high molecular weight volatile groups and other low molecular weight volatile organic compounds generated during curing, such as low molecular weight blocking agents and organic byproducts generated during curing, may be present in amounts such that the relative weight loss of the organic film-forming adhesive deposited on the substrate relative to the weight of the cured organic film-forming adhesive is 5% to 50% by weight of the amount of the organic film-forming adhesive, such as 7% to 45% by weight, 9% to 40% by weight, 11% to 35% by weight, or 13% to 30% by weight.

[0107] Polyepoxides are suitable curing agents for polymers having carboxylic acid groups and / or amine groups. Examples of suitable polyepoxides include low molecular weight polyepoxides such as methyl 3,4-epoxycyclohexanecarboxylate and bis(3,4-epoxy-6-methylcyclohexyl-methyl)adipate. High molecular weight polyepoxides, including polyglycidyl ethers containing the polyphenols and polyols described above, are also suitable as crosslinking agents.

[0108] β-hydroxyalkylamides are suitable curing agents for polymers containing carboxylic acid groups. The structure of β-hydroxyalkylamides can be described as follows:

[0109]

[0110] Each R2 hydrogen atom or a lower alkyl group containing 1 to 5 carbon atoms may contain a mixture of substituents, or:

[0111]

[0112] R2 is a hydrogen atom or a lower alkyl group containing 1 to 5 carbon atoms, comprising a mixture of substituents; A is a bond or polyvalent organic group derived from a saturated, unsaturated, or aromatic hydrocarbon, wherein the saturated, unsaturated, or aromatic hydrocarbon comprises a substituted hydrocarbon group containing 2 to 20 carbon atoms; m' is equal to 1 or 2; n' is equal to 0 or 2, and m'+n' is at least 2, typically in the range of 2 to 4 (and inclusive). Most commonly, A is C2 to C3. 12 Divalent alkylene groups.

[0113] Polybasic acids, especially polycarboxylic acids, are suitable curing agents for polymers with epoxy functional groups. Examples of suitable polycarboxylic acids include adipic acid, succinic acid, sebacic acid, azelaic acid, and dodecanoic acid. Other suitable polybasic acid crosslinking agents include acid-containing acrylic polymers prepared from an olefinic unsaturated monomer containing at least one carboxylic acid group and at least one olefinic unsaturated monomer without a carboxylic acid group. Based on the total solid weight of the acid-functional acrylic polymer, the acid equivalent of such acid-functional acrylic polymers can be 100-2,000 g / mol. Polyesters containing acid functional groups can also be used. Low molecular weight polyesters and hemiesters based on the condensation of aliphatic polyols with aliphatic and / or aromatic polycarboxylic acids or anhydrides can be used. Examples of suitable aliphatic polyols include ethylene glycol, propylene glycol, butanediol, 1,6-hexanediol, trimethylolpropane, di-trimethylolpropane, neopentyl glycol, 1,4-cyclohexanediol, pentaerythritol, etc. Polycarboxylic acids and anhydrides may in particular include terephthalic acid, isophthalic acid, phthalic acid, phthalic anhydride, tetrahydrophthalic anhydride, tetrahydrophthalic anhydride, hexahydrophthalic anhydride, methylhexahydrophthalic anhydride, chlorhexidine anhydride, etc. Mixtures of acids and / or anhydrides may also be used. The polycarboxylic acid crosslinking agents described above are further described in detail in column 6, lines 45 through 9, lines 54 of U.S. Patent No. 4,681,811, the referenced portion of which is incorporated herein by reference.

[0114] Non-limiting examples of suitable polyamine crosslinkers include primary or secondary diamines or polyamines, wherein the group attached to the nitrogen atom can be saturated or unsaturated, aliphatic, alicyclic, aromatic, aromatic-substituted aliphatic, aliphatic-substituted aromatic, and heterocyclic. Non-limiting examples of suitable aliphatic and alicyclic diamines include 1,2-ethylenediamine, 1,2-propanediamine, 1,8-octanediamine, isophoronediamine, propane-2,2-cyclohexylamine, etc. Non-limiting examples of suitable aromatic diamines include phenylenediamine and toluenediamine, such as o-phenylenediamine and p-toluenediamine. Polynuclear aromatic diamines, such as 4,4'-biphenylenediamine, methylenediphenylamine, and monochloromethylenediphenylamine, are also suitable.

[0115] Examples of suitable aliphatic diamines include, but are not limited to, ethylenediamine, 1,2-diaminopropane, 1,4-diaminobutane, 1,3-diaminopentane, 1,6-diaminohexane, 2-methyl-1,5-pentanediamine, 2,5-diamino-2,5-dimethylhexane, 2,2,4- and / or 2,4,4-trimethyl-1,6-diaminohexane, 1,11-diaminoundecane, 1,12-diaminododecane, 1,3-cyclohexanediamine and / or 1,4-cyclohexanediamine, 1-amino-3,3,5-trimethyl-5 -Aminomethyl-cyclohexane, 2,4- and / or 2,6-hexahydrotoluene diamine, 2,4'- and / or 4,4'-diamino-dicyclohexylmethane and 3,3'-dialkyl-4,4'-diamino-dicyclohexylmethane (such as 3,3'-dimethyl-4,4'-diamino-dicyclohexylmethane and 3,3'-diethyl-4,4'-diamino-dicyclohexylmethane), 2,4-diaminotoluene and / or 2,6-diaminotoluene, and 2,4'-diaminobiphenylmethane and / or 4,4'-diaminobiphenylmethane or mixtures thereof. Alicyclic diamines are commercially available from Huntsman Corporation (Houston, TX) under the name JEFFLINK, such as JEFFLINK 754. Other aliphatic cyclic polyamines may also be used, such as DESMOPEN NH 1520, available from Covestro, and / or CLEARLINK 1000, a secondary aliphatic diamine, available from Dorf Ketal. POLYCLEAR 136, the reaction product of isophorone diamine and acrylonitrile (available from BASF / Hansen Group LLC), is also suitable. Other exemplary suitable polyamines are described in column 6, lines 61 through 7, lines 26 of U.S. Patent No. 4,046,729 and column 3, lines 13 through 50 of U.S. Patent No. 3,799,854, the references to which are incorporated herein by reference. Other polyamines may also be used, such as ANCAMINE, available from Evonik.

[0116] Suitable polyamides include any of the polyamides known in the art. For example, ANCAMIDE polyamide is available from Evonik.

[0117] Suitable polyenes can include polyenes represented by the following formula:

[0118] A-(X) m

[0119] Where A is the organic moiety, X is the olefinic unsaturated moiety, and m is at least 2, typically 2 to 6. Examples of X are groups having the following structures:

[0120]

[0121] Each R3 is a group selected from H and methyl.

[0122] Polyolefins can be compounds or polymers containing olefinic double bonds in their molecules that can polymerize upon exposure to radiation. Examples of such materials are (meth)acrylic acid-functionalized (meth)acrylic acid copolymers, epoxy (meth)acrylates, polyester (meth)acrylates, polyether (meth)acrylates, polyurethane (meth)acrylates, amino (meth)acrylates, silicone (meth)acrylates, and melamine (meth)acrylates. The number-average molar mass (Mn) of these compounds is typically from 200 to 10,000, as determined by GPC using polystyrene as a standard. The molecules typically contain an average of 2 to 20 olefinic double bonds that can polymerize upon exposure to radiation. Aliphatic and / or alicyclic (meth)acrylates are frequently used in each case. (Cyclic)aliphatic polyurethane (meth)acrylates and (cyclic)aliphatic polyester (meth)acrylates are particularly suitable. Adhesives can be used alone or in combination.

[0123] Specific examples of polyurethane (meth)acrylates are polyisocyanates such as 1,6-hexamethylene diisocyanate and / or isophorone diisocyanate, comprising reaction products of isocyanurates and their biuret derivatives with hydroxyalkyl (meth)acrylates such as hydroxyethyl (meth)acrylates and / or hydroxypropyl (meth)acrylates. Polyisocyanates can react with hydroxyalkyl (meth)acrylates in a 1:1 equivalence ratio or in an NCO / OH equivalence ratio greater than 1 to form NCO-containing reaction products that can then be chain-extended with polyols such as diols or triols, for example 1,4-butanediol, 1,6-hexanediol, and / or trimethylolpropane. Examples of polyester (meth)acrylates are reaction products of (meth)acrylic acid or anhydrides with polyols such as diols, triols, and tetraols, comprising alkylated polyols such as propoxylated diols and triols. Examples of polyols include 1,4-butanediol, 1,6-hexanediol, neopentyl glycol, trimethylolpropane, pentaerythritol, and propoxylated 1,6-hexanediol. Specific examples of polyester (meth)acrylates are glycerol tri(meth)acrylate, trimethylolpropane tri(meth)acrylate, pentaerythritol tri(meth)acrylate, and pentaerythritol tetra(meth)acrylate.

[0124] Besides (meth)acrylates, (meth)allyl compounds or polymers can be used alone or in combination with (meth)acrylates. Examples of (meth)allyl materials are polyallyl ethers, such as diallyl ether of 1,4-butanediol and triallyl ether of trimethylolpropane. Other examples of (meth)allyl materials are polyurethanes containing (meth)propylene groups. For example, the reaction products of polyisocyanates such as 1,6-hexamethylene diisocyanate and / or isophorone diisocyanate (including isocyanurates and their biuret derivatives) with hydroxyl-functionalized allyl ethers such as monoallyl ether of 1,4-butanediol and diallyl ether of trimethylolpropane. Polyisocyanates can react with hydroxy-functional allyl ethers in a 1:1 equivalent ratio or in an NCO / OH equivalent ratio greater than 1 to form NCO-containing reaction products that can then be chain-extended with polyols (such as diols or triols, for example 1,4-butanediol, 1,6-hexanediol and / or trimethylolpropane).

[0125] As used herein, the term "polythiol functional material" refers to a multifunctional material containing two or more thiol functional groups (SH). Suitable polythiol functional materials for forming curable film-forming compositions are diverse and can vary widely. Such polythiol functional materials may include those known in the art. Non-limiting examples of suitable polythiol functional materials may include polythiols having at least two thiol groups, comprising compounds and polymers. Polythiols may have ether bonds (-O-), sulfur bonds (-S-), and combinations of such bonds, wherein the sulfur bonds include polysulfide bonds (-S-). x -), where x is at least 2, such as 2 to 4.

[0126] The polythiols used in this disclosure comprise materials of the following formula:

[0127] R4-(SH) n ,

[0128] Where R4 is the multivalent organic part, and n' is an integer of at least 2, typically 2 to 6.

[0129] Suitable, non-limiting examples of polythiols include esters of thiol-containing acids of the formula HS-R5-COOH, wherein R5 is an acid having the structure R6-(OH). n The organic portion of the polyhydroxy compound, wherein R6 is the organic portion and n' is at least 2, typically 2 to 6. These components can be reacted under suitable conditions to obtain a polythiol having the following general structure:

[0130]

[0131] R5, R6, and n' are as defined above.

[0132] Examples of thiol-containing acids are mercaptoacetic acid (HS-CH2COOH), α-mercaptopropionic acid (HS-CH(CH3)-COOH), and β-mercaptopropionic acid (HS-CH2CH2COOH) with polyhydroxy compounds such as diols, triols, tetraols, pentylols, hexaols, and mixtures thereof. Other non-limiting examples of suitable polythiols include ethylene glycol bis(thioacetate), ethylene glycol bis(β-mercaptopropionate), trimethylolpropane tri(thioacetate), trimethylolpropane tri(β-mercaptopropionate), pentaerythritol tetra(thioacetate), and pentaerythritol tetra(β-mercaptopropionate), and mixtures thereof.

[0133] Suitable polyacids and polyols that can be used as curing agents include any of the polyacids and polyols known in the art, such as those described herein for the preparation of polyesters.

[0134] Suitable mixtures of crosslinking agents may also be used in this disclosure.

[0135] The amount of curing agent (b) in the curable film-forming composition typically ranges from 5 wt% to 75 wt% based on the total weight of solids in the curable film-forming composition. For example, the minimum amount of crosslinking agent can be at least 5 wt%, typically at least 10 wt%, and more typically at least 15 wt% based on the total weight of solids in the curable film-forming composition. The maximum amount of crosslinking agent can be 75 wt%, more typically 60 wt% or 50 wt% based on the total weight of solids in the curable film-forming composition. The range of crosslinking agent based on the total weight of solids in the curable film-forming composition can include, for example, 5 wt% to 50 wt%, 5 wt% to 60 wt%, 10 wt% to 50 wt%, 10 wt% to 60 wt%, 10 wt% to 75 wt%, 15 wt% to 50 wt%, 15 wt% to 60 wt%, and 15 wt% to 75 wt%.

[0136] The resin component (a) may include epoxide functional groups, and the curing agent component (b) may include amine functional groups. For example, the coating composition may include, substantially consist of, or consist of a film-forming binder, said film-forming binder comprising at least one of a resin component containing epoxide functional groups, a curing agent containing amine functional groups, an organic solvent, and the corrosion inhibitors discussed above.

[0137] The non-electrodepositable coating composition further includes a corrosion inhibitor containing azole.

[0138] "Corrosion inhibitor" will be understood as a compound that inhibits the corrosion of metals. The effectiveness of corrosion inhibitors in cured coatings in preventing corrosion of the substrate to which the coating composition is applied and cured can be demonstrated by salt spray corrosion testing according to ASTM B117. Whether a corrosion inhibitor improves corrosion resistance can be determined by testing the ability of a cured coating containing a corrosion inhibitor to improve corrosion performance, such as by measuring one or more methods, such as by reducing scratch corrosion, scratch gloss, and / or reducing the number and / or size of bubbles present in the coating adjacent to the scratch when compared to a similar composition that does not contain a corrosion inhibitor.

[0139] Examples of suitable azoles include benzotriazoles such as 5-methylbenzotriazole, tolyltriazole, 2,5-dimercapto-1,3,4-thiadiazole, 2-mercaptobenzothiazole, 2-mercaptobenzimidazole, 1-phenyl-5-mercaptotetrazole, 2-amino-5-mercapto-1,3,4-thiadiazole, 2-mercapto-1-methylimidazole, 2-amino-5-ethyl-1,3,4-thiadiazole, 2-amino-5-ethylthio-1,3,4-thiadiazole, 5-phenyltetrazole, 7h-imidazo(4,5-d)pyrimidine, and 2-aminothiazole. Salts of any of the foregoing, such as sodium and / or zinc salts, are also suitable. Other azoles include 2-hydroxybenzothiazole, benzothiazole, 1-phenyl-4-methylimidazole, and 1-(p-tolyl)-4-methylimidazole. Suitable azole-containing products are commercially available from WPC Technologies as HYBRICOR 204, HYBRICOR 204S, and INHIBICOR 1000. Mixtures of azoles can also be used.

[0140] Based on the total resin solids weight of the coating composition, the corrosion inhibitor may be present in an amount of at least 1% by weight, such as at least 3%, at least 5%, at least 7%, at least 9%, or at least 10% by weight, and may not exceed 50% by weight, such as not exceeding 40% by weight, at least 35% by weight, at least 30% by weight, at least 25% by weight, or at least 20% by weight. Based on the total resin solids weight of the coating composition, the corrosion inhibitor may be present in an amount of 1% to 50% by weight, such as 3% to 40% by weight, such as 5% to 35% by weight, such as 7% to 30% by weight, such as 9% to 25% by weight, or at least 10% to 20% by weight.

[0141] The curable film-forming composition disclosed herein comprises (1) a curable organic film-forming binder component (i.e., (a) a resin component and (b) a curing agent component) and (2) a corrosion inhibitor, and can be provided and stored as a one-package composition prior to use. A one-package composition will be understood as a composition in which all coating components remain in the same container after preparation, during storage, etc. Typical one-package coatings can be applied to a substrate and cured by any conventional method, such as by heating, forced air, radiation curing, etc. For some coatings, such as environmentally curable coatings, it is not feasible to store them as a one-package, but they must be stored as a multi-package coating to prevent the components from curing prior to use. The term "multi-package coating" means a coating in which each component is individually maintained until application. The coatings of the present invention can also be multi-package coatings, such as two-package coatings.

[0142] Therefore, components (a) and (b) can be supplied in single packages (1K) or multiple packages, such as two-package (2K) systems. Components of the organic film-forming binder (1) are typically supplied in separate packages and mixed together immediately before reaction. When the reaction mixture is a multi-package system, the corrosion inhibitor (2) can be present in one or both of the individual components (a) and (b) and / or packaged as an additional separate component.

[0143] The curable film-forming compositions disclosed herein may additionally include optional components commonly used in such compositions. For example, the composition may further include a hindered amine light stabilizer for resistance to UV degradation. Such hindered amine light stabilizers comprise those disclosed in U.S. Patent No. 5,260,135. When a hindered amine light stabilizer is used, it is typically present in the composition in an amount of 0.1% to 2% by weight, based on the total weight of the resin solids in the film-forming composition. Other optional additives may be included, such as colorants, plasticizers, abrasion-resistant particles, film-reinforcing particles, flow control agents, thixotropic agents, rheology modifiers, fillers, catalysts, antioxidants, antimicrobial agents, defoamers, surfactants, wetting agents, dispersing agents, adhesion promoters, UV light absorbers and stabilizers, stabilizers, organic cosolvents, reactive diluents, abrasive media, and other conventional additives or combinations thereof. As used herein, the term "colorant" is as defined in paragraphs 29 to 38 of U.S. Patent Publication No. 2012 / 0149820, the referenced portion of which is incorporated herein by reference.

[0144] "Abrasion-resistant particles" refer to particles that, when used in a coating, impart a degree of abrasion resistance to the coating compared to an identical coating lacking particles. Suitable abrasion-resistant particles include organic and / or inorganic particles. Examples of suitable organic particles include, but are not limited to, diamond particles, such as diamond dust particles, and particles formed from carbide materials; examples of carbide particles include, but are not limited to, titanium carbide, silicon carbide, and boron carbide. Examples of suitable inorganic particles include, but are not limited to: silica; alumina; aluminum silicate; silica-alumina; alkali aluminosilicates; borosilicate glass; nitrides, including boron nitride and silicon nitride; oxides, including titanium dioxide and zinc oxide; quartz; nepheline syenite; zircon, such as zircon in the form of zirconium oxide; buddeluyite; and eudialyte. Particles of any size can be used, as well as mixtures of different particle sizes and / or particle sizes.

[0145] As used herein, the terms "adhesion promoter" and "adhesion promoting component" refer to any material that, when included in a composition, enhances the adhesion of the coating composition to a metal substrate. Such adhesion promoting components typically include free acids. As used herein, the term "free acid" is intended to encompass organic and / or inorganic acids contained as a separate component of the composition, and not any acid that can be used to form polymers that may be present in the composition. Free acids may include tannic acid, gallic acid, phosphoric acid, phosphorous acid, citric acid, malonic acid, derivatives thereof, or mixtures thereof. Suitable derivatives comprise esters, amides, and / or metal complexes of such acids. Typically, free acids include phosphoric acid, such as 100% orthophosphoric acid, hyperphosphoric acid, or aqueous solutions thereof, such as 70% to 90% phosphoric acid solutions.

[0146] Besides or alternative to such free acids, other suitable adhesion-promoting components are metal phosphates, organophosphates, and organophosphonates. Suitable organophosphates and organophosphonates include those disclosed in U.S. Patent No. 6,440,580, column 3, lines 24 through 6, line 22; U.S. Patent No. 5,294,265, column 1, lines 53 through 2, line 55; and U.S. Patent No. 5,306,526, column 2, lines 15 through 3, line 8, the reference portions of which are incorporated herein by reference. Suitable metal phosphates include, for example, zinc phosphate, iron phosphate, manganese phosphate, calcium phosphate, magnesium phosphate, cobalt phosphate, zinc iron phosphate, zinc manganese phosphate, and zinc calcium phosphate, including the materials described in U.S. Patent Nos. 4,941,930, 5,238,506, and 5,653,790. As noted above, phosphates are excluded in certain circumstances.

[0147] Adhesion-promoting components may include phosphated epoxy resins. Such resins may comprise reaction products of one or more epoxy-functionalized materials and one or more phosphorus-containing materials. Non-limiting examples of such materials applicable to this disclosure are disclosed in column 3, lines 19-62 of U.S. Patent No. 6,159,549, the reference portion of which is incorporated herein by reference.

[0148] The curable film-forming compositions disclosed herein may further include alkoxysilane adhesion promoters, such as acryloyloxyalkoxysilanes like γ-acryloyloxypropyltrimethoxysilane and methacrylate alkoxysilanes like γ-methacryloyloxypropyltrimethoxysilane, and epoxy-functionalized silanes like γ-glycidoxypropyltrimethoxysilane. Exemplary suitable alkoxysilanes are described in column 2, lines 23 to 65 of U.S. Patent No. 6,774,168, the reference portion of which is incorporated herein by reference.

[0149] The adhesion promoter component (if used) is typically present in the coating composition in an amount ranging from 0.05 wt% to 20 wt%, such as at least 0.05 wt% or at least 0.25 wt%, and at most 20 wt% or at most 15 wt%, ranging from 0.05 wt% to 15 wt%, 0.25 wt% to 15 wt%, or 0.25 wt% to 20 wt%, wherein the weight percentage is based on the total weight of the resin solids in the composition.

[0150] The curable film-forming compositions disclosed herein may include one or more solvents comprising water and / or an organic solvent. Suitable organic solvents include glycols, glycol ether alcohols, alcohols, ketones, and aromatics such as xylene and toluene, acetates, mineral oils, naphthalene, and / or mixtures thereof. “Acetate” includes glycol ether acetates. The solvent may be a non-aqueous solvent. “Non-aqueous solvent” and similar terms mean that less than 50 wt% of the solvent is water. For example, less than 10 wt%, or even less than 5 wt% or 2 wt% of the solvent may be water. It should be understood that mixtures of solvents containing less than 50 wt% water or containing no water may constitute a “non-aqueous solvent.” The composition may be aqueous or water-based. This means that more than 50 wt% of the solvent is water. Such compositions have less than 50 wt%, such as less than 20 wt%, less than 10 wt%, less than 5 wt%, or less than 2 wt% of an organic solvent.

[0151] Substrate

[0152] According to this disclosure, the coating system of this disclosure can be applied to a substrate. Suitable substrates include metallic substrates, metallic alloy substrates, and / or metallized substrates, such as nickel-plated plastics. Alternatively, the substrate may include a non-metallic conductive material comprising a composite material, such as a material comprising carbon fiber or conductive carbon. According to this disclosure, the metal or metallic alloy may include, for example, cold-rolled steel, hot-rolled steel, zinc-coated steel, zinc compounds, or zinc alloys, such as electro-galvanized steel, hot-dip galvanized steel, galvanized annealed steel, GALVANNEAL steel, nickel-plated steel, and zinc-plated steel. Steel substrates coated with a weldable, zinc-rich or iron-phosphide-rich organic coating (such as cold-rolled steel or any of the steel substrates listed above) are also suitable for this disclosure. Such weldable coating compositions are disclosed in U.S. Patent Nos. 4,157,924 and 4,186,036. The substrate may include aluminum, aluminum alloys, zinc-aluminum alloys, such as GALFAN, GALVALUME, aluminized steel, and aluminized alloy steel substrates. Non-limiting examples of aluminum alloys include the 1XXX, 2XXX, 3XXX, 4XXX, 5XXX, 6XXX, or 7XXX series, such as 2024, 7075, and 6061 as specific examples, as well as clad aluminum alloys and cast aluminum alloys, such as the A356 series. The substrate may include magnesium alloys. Non-limiting examples of magnesium alloys, such as the AZ31B, AZ91C, AM60B, or EV31A series, may also be used as substrates. The substrate used in this disclosure may also include other suitable non-ferrous metals, such as titanium or copper, and alloys of these materials. The substrate may also include more than one metal or metal alloy, as the substrate may be a combination of two or more metal substrates assembled together, such as hot-dip galvanized steel assembled with an aluminum substrate.

[0153] Suitable metal substrates used in this disclosure include metal substrates commonly used in: assemblies of vehicle bodies (e.g., but not limited to doors, body panels, trunk lids, top panels, hoods, top and / or longitudinal beams, rivets, landing gear assemblies and / or skins used on aircraft), vehicle frames, vehicle parts, motorcycles, wheels, industrial structures and components such as household appliances including washing machines, dryers, refrigerators, stoves, dishwashers, etc., agricultural equipment, lawn and garden equipment, air conditioning units, heat pump units, lawn furniture, and other articles. The substrate may include the vehicle or a portion or component of said vehicle. The term "vehicle" is used in its broadest sense and includes all types of aircraft, spacecraft, ships, and land-based vehicles. For example, a vehicle may include aircraft such as airplanes, including private aircraft as well as small, medium, or large commercial passenger aircraft, cargo aircraft, and military aircraft; helicopters, including private, commercial, and military helicopters; unmanned aerial vehicles; and aerospace vehicles, including rockets and other spacecraft. The vehicle may include land vehicles such as trailers, cars, trucks, buses, vans, construction vehicles, golf carts, motorcycles, bicycles, trains, and railway vehicles. The vehicle may also include water vehicles such as ships, boats, and hovercraft. The aqueous resin dispersion can be used to coat surfaces and their components. Components may include multiple surfaces. Components may comprise a portion of a larger component, assembly, or device. A portion of a component may be coated with the aqueous resin dispersion of this disclosure, or the entire component may be coated.

[0154] The metal substrate can be cylindrical, such as a pipe, including, for example, cast iron pipe. The metal substrate can also be in the form of, for example, metal sheet or prefabricated component. The substrate can also include a conductive or non-conductive substrate at least partially coated with a conductive coating. The conductive coating can include a conductive agent, such as graphene, conductive carbon black, conductive polymer, or conductive additive. It will also be understood that the substrate can be pretreated with a pretreatment solution. Non-limiting examples of pretreatment solutions include zinc phosphate pretreatment solutions, such as those described in U.S. Patent Nos. 4,793,867 and 5,588,989, and zirconium-containing pretreatment solutions, such as those described in U.S. Patent Nos. 7,749,368 and 8,673,091. Other non-limiting examples of pretreatment solutions include those comprising trivalent chromium, hexavalent chromium, lithium salts, permanganates, rare earth metals such as yttrium, or lanthanides such as cerium. Another non-limiting example of a suitable surface pretreatment solution is a sol-gel, such as a sol-gel comprising alkoxy-silanes, alkoxy-zirconates, and / or alkoxy-titanates. Alternatively, the substrate may be an untreated substrate, such as a bare substrate, that has not been pretreated with the pretreatment solution.

[0155] The substrate may optionally undergo other treatments prior to coating. For example, the substrate may be cleaned, deoxidized, anodized, pickled, subjected to plasma treatment, laser treatment, or ion vapor deposition (IVD). These optional treatments may be used alone or in combination with a pretreatment solution. The substrate may be new (i.e., newly constructed or manufactured) or may be refurbished, for example, in the case of refurbishing or repairing components of a car or aircraft.

[0156] Coating methods and multi-layer coated metal substrates

[0157] This disclosure also relates to a method of coating a metal substrate, the method comprising electrodepositing an electrodeposable coating composition described above onto at least a portion of the substrate to form an electrodeposited coating; and applying a non-electropposable coating composition described above onto at least a portion of the electrodeposited coating to form a second coating.

[0158] According to this disclosure, such methods include electrophoretically applying an electrodeposable coating composition as described above to at least a portion of a substrate.

[0159] According to this disclosure, the anion-electrodepositable coating composition of this disclosure can be deposited on a conductive substrate by contacting the composition with a conductive cathode and a conductive anode, wherein the surface to be coated is the cathode. Upon contact with the composition, an adhesive film of the coating composition is deposited on the anode when a sufficient voltage is applied between the electrodes. The conditions for electrodeposition are generally similar to those used in the electrodeposition of other types of coatings. The applied voltage can vary and can be, for example, from as low as one volt to as high as several kilovolts, such as between 50 volts and 500 volts. The current density can be between 0.5 amperes per square foot and 15 amperes per square foot, and tends to decrease during electrodeposition, indicating the formation of an insulating film.

[0160] Once the anion-electrodeposited coating composition is electrodeposited onto at least a portion of a conductive substrate, the coated substrate can be heated to a temperature and sustained for a time sufficient to at least partially cure the electrodeposited coating on the substrate. As used herein, the term "at least partially cured" with respect to a coating means the formation of a coating by subjecting the coating composition to curing conditions that cause at least a portion of the reactive groups of the components of the coating composition to chemically react to form the coating. The coated substrate can be heated to temperatures ranging from 200℉ to 450℉ (93°C to 232.2°C), such as 275℉ to 400℉ (135°C to 204.4°C) or 300℉ to 360℉ (149°C to 180°C). The curing time can depend on the curing temperature and other variables, such as the film thickness of the electrodeposited coating, the level and type of catalyst present in the composition, etc. For the purposes of this disclosure, all that is necessary is sufficient time to allow the coating on the substrate to cure. For example, the curing time can range from 10 to 60 minutes, such as 20 to 40 minutes. The thickness of the resulting cured electrodeposited coating can range from 15 to 50 micrometers.

[0161] According to this disclosure, the method may include (a) electrophoretically depositing the electrodeposable coating composition of this disclosure onto at least a portion of a substrate; and (b) heating the coated substrate to a temperature and holding for a time sufficient to cure the electrodeposited coating on the substrate. According to this disclosure, the method may optionally further include (c) directly applying one or more non-electropposable coating compositions as described above onto the at least partially cured electrodeposited coating to form a second coating on at least a portion of the at least partially cured electrodeposited coating; and (d) heating and / or drying the coated substrate from step (c) to a temperature and holding for a time sufficient to cure the second coating.

[0162] The non-electrodepositable coating compositions disclosed herein can be applied to substrates using known application techniques such as dipping or immersion, spraying, intermittent spraying, post-dipping spraying, post-spraying dipping, brushing, or roller coating. Common spraying techniques and equipment used for air spraying and electrostatic spraying, whether manual or automated, can be used.

[0163] After applying a non-electrodepositable coating composition to at least a portion of an electrodeposited coating to form a second coating, the solvent, i.e., organic solvents and / or water, is removed from the second coating by heating or air drying for a period of time. Suitable drying conditions will depend on the specific composition and / or application, but in some cases, a drying time of about 1 to 5 minutes at a temperature of about 70℉ to 250℉ (27°C to 121°C) will be sufficient. If desired, more than one coating of the non-electrodepositable coating composition can be applied. Typically, between coatings, the previously applied coating is flash-evaporated; i.e., exposed to ambient conditions for the desired amount of time. The thickness of the second coating can be 0.1 to 3 mils (2.5 to 75 micrometers), such as 0.2 to 2.0 mils (5.0 to 50 micrometers). The non-electrodepositable coating composition can then be heated. During the curing operation, the solvent is removed and the crosslinkable components of the composition are crosslinked. Heating and curing operations are sometimes performed in a temperature range of 70℉ to 250℉ (27℃ to 121℃), but lower or higher temperatures may be used if required. As previously mentioned, the coatings disclosed herein can also be cured without the addition of heat or a drying step. Alternatively, a coating may be applied, and then a second coating may be applied "wet-on-wet". Alternatively, the coating may be cured prior to the application of one or more additional coatings.

[0164] The systems and methods disclosed herein can be used to form multilayer coated composites comprising a substrate having various coatings. The coatings may comprise a pretreatment layer, such as a phosphate layer (e.g., a zinc phosphate layer), an electrodeposited layer, and a second coating comprising a corrosion inhibitor containing azoles. The second coating may be a primer or topcoat (e.g., a base coat, a clear coat, a colored single-coat, and a colored-plus-clear composite composition), and the substrate may optionally include an additional topcoat on the second coating. It should be understood that, in addition to the second coating, suitable topcoats may comprise any of those topcoats known in the art, and each may independently be aqueous, solvent-based, in solid particulate form (i.e., a powder coating composition), or in the form of a powder paste. Topcoats typically comprise a film-forming polymer, a crosslinking material, and one or more pigments (if a colored base coat or single-coat). According to this disclosure, one or more topcoats may be applied to a substantially uncured substrate. For example, a clear coat may be applied to at least a portion of a substantially uncured base coat (wet-on-wet), and both layers may be cured simultaneously in a downstream process.

[0165] According to this disclosure, additional components, such as colorants and fillers, can be present in various coating compositions that produce the topcoat. Any suitable colorant and filler can be used. For example, 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 coatings of this disclosure. It should be noted that, generally, the colorant can be present in any amount sufficient to impart the desired properties, visual and / or color effects in one layer of the multilayer composite material.

[0166] Example colorants include pigments, dyes, and colorants, such as those used in the coatings industry and / or listed in the Dry Powder Pigment Manufacturers Association (DCMA), as well as special effects compositions. Colorants may comprise, for example, finely divided solid powders that are insoluble but wettable under operating conditions. Colorants may be organic or inorganic, and may be agglomerated or non-agglomerated. Colorants can be incorporated into the coating by grinding or simple mixing. Colorants can also be incorporated into the coating by grinding with an abrasive medium such as an acrylic abrasive, the use of which is well known to those skilled in the art.

[0167] Example pigments and / or pigment compositions include, but are not limited to, carbazole dioxazine crude pigments, azo, monoazo, diazo, naphthol AS, salts (salt lakes), benzimidazolone, condensates, metal complexes, isoindolineone, isoindoline and polycyclic phthalocyanine, quinacridone, perylene, perinone, diketopyrrolopyrrole, thioindigo, anthraquinone, indigoanthraquinone, anthraquinone pyrimidine, flavinanthraquinone, pinanthraquinone, anthraquinone, dioxazine, triaryl cations, quinophthalone pigments, pyrrolopyrrole dione red (“DPP Red BO”), titanium dioxide, carbon black, zinc oxide, antimony oxide, etc., as well as organic or inorganic UV opaque pigments (such as iron oxide), transparent red or yellow iron oxide, phthalocyanine blue and mixtures thereof. The terms “pigment” and “colored filler” may be used interchangeably.

[0168] Example dyes include, but are not limited to, solvent-based dyes and / or water-based dyes, such as acid dyes, azo dyes, basic dyes, direct dyes, disperse dyes, reactive dyes, solvent dyes, sulfur dyes, mordant dyes, for example, bismuth vanadate, anthraquinone, perylene, aluminum, quinacridone, thiazole, thiazide, azo, indigo derivatives, nitro, nitroso, oxazine, phthalocyanine, quinoline, symmetrical diphenylethylene, and triphenylmethane.

[0169] Example colorants include, but are not limited to, pigments dispersed in a water-based or water-miscible carrier, such as AQUA-CHEM 896, commercially available from Degussa, Inc., CHARISMA colorants, and MAXITONER industrial colorants, commercially available from the Accurate Dispersions division of Eastman Chemical, Inc.

[0170] Colorants can be in dispersion form, including, but not limited to, nanoparticle dispersions. Nanoparticle dispersions can contain one or more highly dispersed nanoparticle colorants and / or colorant particles that produce the desired visible color and / or opacity and / or visual effect. Nanoparticle dispersions can contain colorants such as pigments or dyes with particle sizes less than 150 nm, such as less than 70 nm or less than 30 nm. Nanoparticles can be produced from organic or inorganic pigments from milling feedstocks of abrasive media with particle sizes less than 0.5 mm. Example nanoparticle dispersions and methods for their preparation are identified in U.S. Patent No. 6,875,800B2, which is incorporated herein by reference. Nanoparticle dispersions can also be produced by crystallization, precipitation, vapor-phase condensation, and chemical abrasion (i.e., partial dissolution). To minimize re-agglomeration of nanoparticles within a coating, resin-coated nanoparticle dispersions can be used. As used herein, a "resin-coated nanoparticle dispersion" refers to a continuous phase comprising finely dispersed "composite microparticles" including nanoparticles and a resin coating on the nanoparticles. Example resin-coated nanoparticle dispersions and methods for their manufacture are determined in U.S. Application No. 10 / 876,031, filed June 24, 2004 (which is incorporated herein by reference) and U.S. Provisional Application No. 60 / 482,167, filed June 24, 2003 (which is incorporated herein by reference).

[0171] According to this disclosure, special effect compositions that can be used in one or more layers of a multilayer coated composite material comprise pigments and / or compositions that produce one or more appearance effects, such as reflection, pearlescent, metallic luster, phosphorescence, fluorescence, photochromism, photosensitivity, thermochromism, iridescence, and / or color change. Additional special effect compositions can provide other perceptible properties, such as reflectivity, opacity, or texture. For example, a special effect composition can produce color transfer, such that the color of the coating changes when viewed from different angles. Example color effect compositions are identified in U.S. Patent No. 6,894,086, which is incorporated herein by reference. Additional color effect compositions may comprise transparently coated mica and / or synthetic mica, coated silica, coated alumina, transparent liquid crystal pigments, liquid crystal coatings, and / or any composition, wherein interference arises from a difference in refractive index within the material rather than from a difference in refractive index between the material surface and air.

[0172] According to this disclosure, photosensitive and / or photochromic compositions can be used in many layers of a multilayer composite material, wherein the color of the photosensitive and / or photochromic compositions reversibly changes upon exposure to one or more light sources. The photochromic and / or photosensitive compositions can be activated by exposure to radiation of a specific wavelength. When the composition is excited, its molecular structure changes, and the altered structure exhibits a new color different from the original color of the composition. When the radiation exposure is removed, the photochromic and / or photosensitive composition can revert to a resting state, wherein the original color of the composition is restored. For example, the photochromic and / or photosensitive composition may be colorless in an unexcited state and exhibit color in an excited state. The complete color change can occur within milliseconds to several minutes, such as 20 to 60 seconds. Example photochromic and / or photosensitive compositions contain photochromic dyes.

[0173] According to this disclosure, photosensitive compositions and / or photochromic compositions can be associated with and / or at least partially bound to polymeric materials of polymers and / or polymerizable components, such as by covalent bonding. Unlike some coatings in which photosensitive compositions can migrate out of the coating and crystallize into the substrate, the migration outside the coating of photosensitive compositions and / or photochromic compositions associated with and / or at least partially bound to polymeric components according to this disclosure is minimal. Example photosensitive compositions and / or photochromic compositions and methods of their preparation are identified in U.S. Application Serial No. 10 / 892,919, filed July 16, 2004, and are incorporated herein by reference.

[0174] When there is no intermediate coating between the substrate and the coating, the electrodeposited layer and the second coating of this disclosure can be applied directly to the metal substrate. This means that the substrate can be bare, as described below, or treated with one or more cleaning, deoxidizing, and / or pretreatment compositions described below, or the substrate can be anodized. Alternatively, the substrate may be coated with one or more different coating compositions prior to applying the coating composition of this disclosure. Additional coatings may include sol-gels, adhesion promoters, primers, wash primers, undercoats, or topcoats, and can be applied by any method known in the art, such as dip coating, roll coating, spray coating, brush coating, or electrodeposition.

[0175] As described above, the substrate to be used can be a bare metal substrate. "Bare" means a raw metal substrate that has not been treated with any pretreatment composition, such as conventional phosphating baths, heavy metal washing, etc. Alternatively, the bare metal substrate used in this disclosure can be a cut edge of a substrate that has been otherwise treated and / or coated over the remainder of its surface. Alternatively, the substrate may undergo one or more processing steps known in the art prior to applying the electrodeposited coating and the second coating.

[0176] The substrate can be cleaned using conventional cleaning procedures and materials. These will include mild or strong alkaline cleaners, such as those commercially available and commonly used in metal pretreatment processes. Examples of alkaline cleaners include Chemkleen 163 and Chemkleen 177 (both available from PPG Industries), pretreatment and specialty products, and any of the DFM series, RECC 1001, and 88Xl002 cleaners (commercially available from PRC-DeSoto International, Sylmar, CA), as well as Turco 4215-NCLT and Ridolene (commercially available from Henkel Technologies, Madison Heights, MI). Rinsing with tap water, distilled water, or a combination thereof is typically performed before or after such cleaning. After cleaning with an alkaline cleaner, or as an alternative, the metal surface can be rinsed with an acidic aqueous solution. Examples of rinsing solutions include weak or strong acidic cleaners, such as commercially available dilute nitric acid solutions commonly used in metal pretreatment processes.

[0177] According to this disclosure, at least a portion of the cleaned aluminum substrate surface can be mechanically or chemically deoxidized. As used herein, the term "deoxidation" means the removal of an oxide layer present on the substrate surface to promote uniform deposition of the pretreatment composition (described below) and to promote adhesion of the pretreatment composition coating and / or coating of this disclosure to the substrate surface. Suitable deoxidizers are well known to those skilled in the art. Typical mechanical deoxidizers may be substrate surfaces that have been uniformly roughened, for example by using a scrubbing or 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 Amchem 7 / 17 deoxidizer (available from Henkel Technologies, Madison Heights, Michigan), OAKITE deoxidizer LNC (commercially available from Chemetall), TURCO deoxidizer 6 (commercially available from Henkel), or combinations thereof. Typically, chemical deoxidizers include a carrier, usually an aqueous medium, so that the deoxidizer can be in the form of a solution or dispersion in the carrier. In this case, the solution or dispersion can be brought into contact with the substrate by any of a variety of known techniques, such as impregnation or immersion, spraying, intermittent spraying, spraying after impregnation, impregnation after spraying, brushing, or roller coating.

[0178] The metal substrate can optionally be pickled by treatment with a solution including nitric acid and / or sulfuric acid.

[0179] The metal substrate can optionally be pretreated with any suitable solution 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. The pretreatment solution may be substantially free of environmentally harmful heavy metals such as chromium and nickel. Suitable phosphate conversion coating compositions may be any of the heavy metal-free phosphate conversion coating compositions known in the art. Examples include the most commonly used zinc phosphate, iron phosphate, manganese phosphate, calcium phosphate, magnesium phosphate, cobalt phosphate, zinc iron phosphate, zinc manganese phosphate, zinc calcium phosphate, and other types of layers, which may contain one or more polyvalent 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.

[0180] The transition metals and rare earth metals referred to in this article are those elements contained in such groups as shown in the CAS Periodic Table of the Elements, such as those shown in the Handbook of Chemistry and Physics, 63rd edition (1983).

[0181] 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 can be selected from hexafluorozirconic acid, its alkali metal salts and ammonium salts, zirconium ammonium carbonate, zirconium oxynitrate, zirconium carboxylate, and zirconium hydroxycarboxylate, such as hydrofluoric acid, zirconium acetate, zirconium oxalate, zirconium ammonium glycolate, zirconium ammonium lactate, zirconium ammonium citrate, and mixtures thereof. Hexafluorozirconic acid is the most commonly used. Examples of titanium compounds are fluorotitanic acid and its salts. An example of hafnium compounds is hafnium nitrate. An example of yttrium compounds is yttrium nitrate. An example of cerium compounds is cerium nitrate.

[0182] Typical compositions used in the pretreatment step comprise non-conductive organophosphate and organophosphonate pretreatment compositions, such as those disclosed in U.S. Patents 5,294,265 and 5,306,526. Such organophosphate or organophosphonate pretreatments are commercially available from PPG Industries under the trade name NUPAL.

[0183] In the aerospace industry, anodizing surface treatments and chromium-based conversion coatings / pretreatments are commonly used on aluminum alloy substrates. Examples of anodizing surface treatments include chromic acid anodizing, phosphoric acid anodizing, boric acid-sulfuric acid anodizing, tartaric acid anodizing, and sulfuric acid anodizing. Chromium-based conversion coatings include hexavalent chromium types, such as Henkel's BONDERITE M-CR1200, and trivalent chromium types, such as Henkel's BONDERITE M-CR T5900.

[0184] This disclosure further relates to a multilayer coated metal substrate comprising (a) a metal substrate; (b) an electrodeposited coating present on at least a portion of the metal substrate, wherein the electrodeposited coating comprises a film-forming polymer containing anionic salt groups and a curing agent, and if the film-forming polymer containing anionic salt groups is a phosphating epoxy resin, then the film-forming polymer containing anionic salt groups does not contain urethane functional groups; and (c) a second coating present on at least a portion of the electrodeposited coating, wherein the second coating comprises a corrosion inhibitor containing azole.

[0185] The metal substrate may include any of the metal substrates described above. For example, the metal substrate may include aluminum or an aluminum alloy. The aluminum alloy may include 2000, 3000, 4000, 5000, 6000 or 7000 series aluminum alloys, such as 2024 aluminum alloy, 7075 aluminum alloy or 6061 aluminum alloy.

[0186] The metal substrate may be clad or unclad, and if clad, the clay layer may comprise the same or different material as the metal substrate. For example, the metal substrate may comprise a clad aluminum alloy, and the cladding layer may optionally comprise aluminum or an aluminum alloy.

[0187] The electrodeposited layer may optionally further include a corrosion inhibitor. Non-limiting examples of suitable corrosion inhibitors include azoles, calcium ion-exchanged silica, or any combination thereof.

[0188] Alternatively, the electrodeposited layer may contain virtually no, substantially no, or no corrosion inhibitors at all.

[0189] Non-limiting examples of azoles in the second coating include, substantially composed of, or composed of: 5-methylbenzotriazole, tolyltriazole, 2,5-dimercapto-1,3,4-thiadiazole, 2-mercaptobenzothiazole, 2-mercaptobenzimidazole, 1-phenyl-5-mercaptotetrazole, 2-amino-5-mercapto-1,3,4-thiadiazole, 2-mercapto-1-methylimidazole, 2-amino-5-ethyl-1,3,4-thiadiazole, 2-amino-5-ethylthio-1,3,4-thiadiazole, 5-phenyltetrazole, 7h-imidazo(4,5-d)pyrimidine, 2-aminothiazole, 2-hydroxybenzothiazole, benzothiazole, 1-phenyl-4-methylimidazole and 1-(p-tolyl)-4-methylimidazole, their salts or any combination thereof. For example, the second coating may include a corrosion inhibitor comprising, substantially comprising, or composed of a zinc salt of 2,5-dimercapto-1,3,4-thiadiazole.

[0190] The coated metal substrates of this disclosure can exhibit superior corrosion resistance, as determined by salt spray corrosion resistance testing.

[0191] As used herein, unless otherwise defined, the term “substantially free” means that, based on the total resin solids weight of the composition, the component (if any) is present in an amount of less than 1% by weight.

[0192] As used herein, unless otherwise defined, the term “substantially free” means that, based on the total resin solids weight of the composition, the component (if any) is present in an amount of less than 0.1% by weight.

[0193] As used herein, unless otherwise defined, the term “completely free” means, based on the total resin solids weight of the composition, that the component is not present in the electrodeposable coating composition, i.e., 0.00 wt%.

[0194] For the purposes of this detailed description, it should be understood that alternative variations and sequences of steps may be taken in this disclosure, except where explicitly stated otherwise. Furthermore, except in any operational instance or where otherwise indicated, all figures representing quantities of ingredients as used, for example, in the specification and claims, should in all cases be understood to be modified by the term “about.” Therefore, unless indicated to the contrary, the numerical parameters set forth in the following specification and appended claims are approximations that may vary according to the desired characteristics to be obtained through this disclosure. At least, and without attempting to limit the application of the doctrine of equivalence to the scope of the claims, each numerical parameter should be interpreted at least according to the number of significant figures reported and by applying ordinary rounding techniques.

[0195] Although the numerical ranges and parameters described in this disclosure are approximate, the values ​​illustrated in the specific embodiments are reported as accurately as possible. However, any numerical value inherently contains some error that is necessarily caused by the standard deviation found in its corresponding test measurement results.

[0196] Furthermore, it should be understood that any numerical range described herein is intended to include all subranges included therein. For example, the range “1 to 10” is intended to include all subranges between (and including) the stated minimum value of 1 and the stated maximum value of 10, that is, a minimum value equal to or greater than 1 and a maximum value equal to or less than 10.

[0197] As used herein, the terms “comprising,” “containing,” and similar terms are understood in the context of this application to be synonymous with “comprising” and are therefore open-ended and do not exclude the presence of additional undescribed or unstated elements, materials, ingredients, or method steps. As used herein, “consisting of” is understood in the context of this application to exclude the presence of any unspecified elements, ingredients, or method steps. As used herein, “generally consisting of” is understood in the context of this application to include the specified elements, materials, ingredients, or method steps “as well as those elements, materials, ingredients, or method steps that do not materially affect the essential and novel characteristics of the described content.”

[0198] In this application, unless otherwise specifically stated, the use of the singular includes the plural and the plural encompasses the singular. For example, although "a" film-forming polymer containing anionic salt groups, "a" curing agent, and "a" monomer are mentioned herein, combinations of these components (i.e., multiples of these components) may be used. Additionally, in this application, unless otherwise explicitly stated, the use of "or" means "and / or," even if "and / or" may be explicitly used in certain situations.

[0199] While specific aspects of this disclosure have been described in detail, those skilled in the art will understand that various modifications and alternatives to those details can be developed based on the general teachings of this disclosure. Therefore, the specific arrangements disclosed are intended to be illustrative only and not to limit the scope of the invention, which is defined by the full scope of the appended claims and any and all their equivalents.

[0200] The following examples illustrate this disclosure; however, these examples should not be construed as limiting the disclosure to its details. Unless otherwise indicated, all parts and percentages in the following examples and throughout the specification are by weight.

[0201] Example

[0202] Table 1 provides a description of the materials used in the preparation examples.

[0203]

[0204]

[0205] Table 2: Examples of Electroplating Primers and Topcoats

[0206]

[0207]

[0208] Electrodepositable coating composition and electrodeposited primer coating: The same electrodepositable coating composition was used for each of Comparative Example 1, Comparative Example 2, and Experimental Example 3, and was prepared by the following procedure: Charge 1 was added to a 1-gallon plastic bucket and stirring was initiated. Charge 2 was slowly added over 5 minutes. Finally, Charge 3 was added over 5 minutes. The resulting mixture was stirred for an additional 15 minutes. The coating was then ultrafiltered to remove 50% of the original mass of the bath, which was replaced with an additional amount of deionized water equal to the removed mass to return it to its original starting weight.

[0209] Before electrodeposition coating, prepare a 3×4" bare aluminum alloy substrate panel of 2024T3 as follows: clean the aluminum alloy panel with methyl ethyl ketone wipe, and then process it according to steps 1 to 13 in Table 3 below.

[0210] Table 3

[0211]

[0212] The compositions of the Turco cleaning solution, alkaline etching solution, and nitric acid-sulfuric acid pickling solution are listed in Tables 4, 5, and 6 below, and preparation instructions are provided for each of the following compositions.

[0213] Table 4

[0214]

[0215] Turco cleaning solution was prepared by weighing a specified amount of Turco 4215NC-LT in a 1000 mL beaker, and then adding DI water while stirring thoroughly to dissolve Turco 4215NC-LT to produce a 1000 mL solution.

[0216] Table 5

[0217]

[0218]

[0219] An alkaline etching solution was prepared by weighing charge #2 in a glass container that holds 4000 mL; charge #1 was weighed in a separate container; charge #1 was slowly added to charge #2 with stirring, resulting in an exothermic reaction of the heated solution. The solution was allowed to cool for 15 minutes, and then the remaining charges 3, 4, and 5 were added sequentially while thoroughly mixing between additions.

[0220] Table 6

[0221]

[0222] A nitric acid-sulfuric acid washing solution was prepared by placing charge #1 in a 1000 mL beaker; charge #2 and charge #3 were weighed in two separate containers; charge #2 was then slowly added to the 1000 mL beaker with stirring, followed by charge #3. The addition caused an exothermic reaction that heated the solution. Charge #4 was weighed in a separate container and then slowly added to the 1000 mL beaker with stirring. Once charge #4 dissolved, DI water was added to produce a 1000 mL solution.

[0223] After the test panel was treated, an electrodeposable coating composition was electrodeposited (140V / 90 seconds / 75℉) onto the treated 2024T3 bare test panel, where the aluminum panel served as the electrode. The electrodeposable coating composition was subjected to a temperature of 75℉ and a current of 140V was applied for 90 seconds to electrodeposit the coating. The electrodeposited panel was then baked at 250℉ for 60 minutes. The resulting electrodeposited coating had a dry film thickness of 0.6 to 0.9 mils.

[0224] Second coatingFor component A of the coating compositions of Comparative Example 2 and Experimental Example 3 indicated in Table 2, all materials were weighed and placed into glass jars, and then the dispersion medium was added to each jar at a level approximately equal to half the total weight of the component materials. The jars were sealed with lids and then placed on a Lau dispersion unit for a dispersion time of 3 hours.

[0225] For component B of the coating compositions of Comparative Example 2 and Experimental Example 3 indicated in Table 2, the two materials were placed in a container and thoroughly mixed.

[0226] Components A and B of the non-electrodepositable coating compositions (i.e., the second coating) of Comparative Example 2 and Experimental Example 3 were blended together before being sprayed onto the baked electrodeposited coating. The dry film thickness of the second coating was between 1.4 and 1.7 mils when applied using an air atomizing spray gun.

[0227] The multi-layered coated test panel was aged under ambient conditions for at least 7 days, after which a 10cm by 10cm "X" was scribed into the panel surface to a depth sufficient to penetrate any surface coating and expose the underlying metal. The single-layered test panel of Comparative Example 1 was scribed in the same manner. The scribed coated test panels were then placed in a 5% sodium chloride neutral salt spray chamber (exception: pH and salt concentration were checked weekly, not daily) for 1440 hours according to ASTM B117.

[0228] After exposure, the panel was removed, dried, and its corrosion resistance was analyzed. The rating scale is shown in Table 7 below, and the corrosion data are shown in Table 8.

[0229] Table 7

[0230]

[0231] Table 8

[0232]

[0233] For Comparative Example 1 compared to Experimental Example 3, the results in the table above clearly show that applying a topcoat with an inhibitor over the electrocoating primer resulted in a reduction in both scratch corrosion and dark scratches. For Comparative Example 2 compared to Experimental Example 3, the results in the table show that the electrocoating primer with an inhibitor-containing topcoat has improved scratch corrosion and scratching properties, while eliminating scratch bubbles.

[0234] Table 9-5976 hours

[0235]

[0236]

[0237] For Comparative Example 1 versus Example 3, the results in the table above clearly demonstrate that applying a topcoat with an inhibitor over the electrocoating primer results in a reduction of both scratch corrosion and dark scratches percentage. For Comparative Example 2 versus Example 3, the results in the table show that the electrocoating primer with an inhibitor-containing topcoat exhibits improved scratch corrosion and scratching properties, while eliminating scratch bubbles on the bare alloy and significantly reducing scratch bubbles on the coated alloy.

[0238] Those skilled in the art will understand that many modifications and variations are possible based on the foregoing disclosure without departing from the broad inventive concept described and illustrated herein. Therefore, it should be understood that the foregoing disclosure is merely an illustration of various exemplary aspects of this application, and those skilled in the art can readily make many modifications and variations within the spirit and scope of this application and the appended claims.

Claims

1. A system for coating a metal substrate, the system comprising: An anion-electrodepositable coating composition comprising a film-forming polymer containing anion salt groups and a curing agent, wherein if the film-forming polymer containing anion salt groups is a phosphated epoxy resin, the film-forming polymer containing anion salt groups does not contain urethane functional groups. as well as A non-electrodepositable coating composition, said non-electrodepositable coating composition comprising: Film-forming adhesives containing curable organic resin components; and Corrosion inhibitors containing azoles.

2. The system for coating a metal substrate according to claim 1, wherein the azole in the non-electrodepositable coating composition comprises triazole, benzotriazole, benzothiazole, thiadiazole, imidazole, oxazole, or any combination thereof.

3. The system for coating a metal substrate according to claim 2, wherein the azole in the non-electrodepositable coating composition comprises 5-methylbenzotriazole, tolyltriazole, 2,5-dimercapto-1,3,4-thiadiazole, 2-mercaptobenzothiazole, 2-mercaptobenzimidazole, 1-phenyl-5-mercaptotetrazole, 2-amino-5-mercapto-1,3,4-thiadiazole, 2-mercapto-1-methylimidazole, 2-amino-5-ethyl-1,3,4-thiadiazole, 2-amino-5-ethylthio-1,3,4-thiadiazole, 5-phenyltetrazole, 7h-imidazo(4,5-d)pyrimidine, 2-aminothiazole, 2-hydroxybenzothiazole, benzothiazole, 1-phenyl-4-methylimidazole and 1-(p-tolyl)-4-methylimidazole, their salts or any combination thereof.

4. The system for coating a metal substrate according to claim 3, wherein the azole in the non-electrodepositable coating composition comprises a zinc salt of 2,5-dimercapto-1,3,4-thiadiazole.

5. The system for coating a metal substrate according to claim 4, wherein the azole in the non-electrodepositable coating composition comprises a zinc salt of 2-mercaptobenzothiazole.

6. The system for coating a metal substrate according to claim 1, wherein the anion-electrodepositable coating composition is substantially free of, substantially free of, or completely free of corrosion inhibitors.

7. The system for coating a metal substrate according to claim 1, wherein the anion-electrodepositable coating composition further comprises a corrosion inhibitor.

8. The system for coating a metal substrate according to claim 7, wherein the corrosion inhibitor comprises azole, calcium ion-exchanged silica, or any combination thereof.

9. The system for coating a metal substrate according to claim 1, wherein the non-electrodepositable coating composition comprises an aqueous or solvent-based coating composition.

10. The system for coating a metal substrate according to claim 1, wherein the non-electrodepositable coating composition comprises the film-forming binder comprising: the curable organic resin component; and a curing agent component.

11. The system for coating a metal substrate according to claim 10, wherein the film-forming binder of the non-electrodepositable coating composition comprises a functional group including at least one of the following: carboxylic acid group, amino group, epoxide group, hydroxyl group, thiol group, urethane group, amide group, urea group, (meth)acrylate group, styrene group, vinyl group, allyl group, aldehyde group, acetoacetate group, hydrazide group, cyclic carbonate group, ketone group, carbodiimide group, oxazoline group, alkoxy-silane functional group, isocyanate functional group, maleic acid or anhydride group, or any combination thereof.

12. The system for coating a metal substrate according to claim 11, wherein the organic resin component of the non-electrodepositable coating composition comprises one or more of the following: acrylic polymers, polyesters, polyurethanes, polyamides, polyethers, polysulfides, polysulfides, polythioesters, polythiols, polyenes, polyols, polysilanes, polysiloxanes, fluoropolymers, polycarbonates, and epoxy resins.

13. The system for coating a metal substrate according to claim 10, wherein the curing agent component of the non-electrodepositable coating composition comprises amino plastics, polyisocyanates, polyepoxides, β-hydroxyalkylamides, polybasic acids, organometallic acid functional materials, polyamines, polyamides, polysulfides, polythiols, polyolefins, polyols, polysilanes, or any combination thereof.

14. The system for coating a metal substrate according to claim 10, wherein the organic resin component of the non-electrodepositable coating composition comprises a polymer having epoxide functional groups, and the curing agent component comprises a crosslinking agent containing amino functional groups.

15. The system for coating a metal substrate according to claim 10, wherein the organic resin component of the non-electrodepositable coating composition comprises a polymer having hydroxyl functional groups, and the curing agent component comprises a crosslinking agent containing isocyanate functional groups.

16. The system for coating a metal substrate according to any one of the preceding claims, wherein the film-forming polymer containing anionic salt groups comprises hydroxyl functional groups, primary or secondary amino functional groups, thiol functional groups, carboxylic acid functional groups, or any combination thereof.

17. The system for coating a metal substrate according to claim 16, wherein the film-forming polymer containing anionic salt groups comprises phosphating polyepoxides, phosphating addition polymers, or any combination thereof.

18. The system for coating a metal substrate according to any one of claims 1-15, wherein the curing agent of the electrodepositable coating composition comprises at least partially blocked polyisocyanates, amino plastic resins, phenolic plastic resins, or any combination thereof.

19. The system for coating a metal substrate according to claim 18, wherein the curing agent comprises high molecular weight volatile groups.

20. The system for coating a metal substrate according to claim 19, wherein the high molecular weight volatile groups account for 5% to 50% by weight of the film-forming adhesive.

21. A method for coating a metal substrate, the method comprising: The electrodeposable coating composition of any one of claims 1 to 20 is electrodeposited onto at least a portion of the substrate to form an electrodeposited coating; as well as The non-electrodepositable coating composition of any one of claims 1 to 20 is applied to at least a portion of the electrodeposited coating to form a second coating.

22. The method of claim 21, wherein the application of the non-electrodepositable coating composition comprises dipping, immersion, spraying, intermittent spraying, post-dipping spraying, post-spraying dipping, brushing, roller coating, or any combination thereof.

23. A multilayer coated metal substrate comprising (a) a metal substrate; and (b) an electrodeposited coating, the electrodeposited coating being present on at least a portion of the metal substrate, wherein the electrodeposited coating comprises a film-forming polymer containing anionic salt groups and a curing agent, and if the film-forming polymer containing anionic salt groups is a phosphating epoxy resin, then the film-forming polymer containing anionic salt groups does not contain urethane functional groups. and (c) a second coating, the second coating being present on at least a portion of the electrodeposited coating, wherein the second coating comprises: Film-forming adhesives containing curable organic resin components; And corrosion inhibitors containing azoles.

24. The multilayer coated metal substrate according to claim 23, wherein the electrodeposited coating is electrodeposited from the electrodeposable coating composition of any one of claims 1 to 20.

25. The multilayer coated metal substrate according to claim 23, wherein the second coating is applied by the non-electrodepositable coating composition of any one of claims 1 to 20.

26. The multilayer coated metal substrate of claim 23, wherein the electrodepositable coating composition comprises a corrosion inhibitor, the corrosion inhibitor comprising azole, calcium ion-exchanged silica or any combination thereof, substantially composed of or composed of thereof.

27. The multilayer coated metal substrate of claim 23, wherein the electrodepositable coating composition is substantially free of, substantially free of, or completely free of corrosion inhibitors.

28. The multilayer coated metal substrate of claim 23, wherein the second coating comprises a corrosion inhibitor, the corrosion inhibitor comprising, substantially comprising, or comprising of azoles, wherein the azole comprises, substantially comprises, or comprises of the following: 5-Methylbenzotriazole, tolyltriazole, 2,5-dimercapto-1,3,4-thiadiazole, 2-mercaptobenzothiazole, 2-mercaptobenzimidazole, 1-phenyl-5-mercaptotetrazole, 2-amino-5-mercapto-1,3,4-thiadiazole, 2-mercapto-1-methylimidazole, 2-amino-5-ethyl-1,3,4-thiadiazole, 2-amino-5-ethylthio-1,3,4-thiadiazole, 5-phenyltetrazole, 7h-imidazo(4,5-d)pyrimidine, 2-aminothiazole, 2-hydroxybenzothiazole, benzothiazole, 1-phenyl-4-methylimidazole and 1-(p-tolyl)-4-methylimidazole, their salts or any combination thereof.

29. The multilayer coated metal substrate of claim 28, wherein the second coating comprises a corrosion inhibitor, the corrosion inhibitor comprising, substantially comprising, or comprising a zinc salt of 2,5-dimercapto-1,3,4-thiadiazole.

30. The multilayer coated metal substrate of claim 28, wherein the second coating comprises a corrosion inhibitor, the corrosion inhibitor comprising, substantially comprising, or comprising a zinc salt of 2-mercaptobenzothiazole.

31. The multilayer coated metal substrate according to any one of claims 23 to 30, wherein the metal substrate comprises aluminum or an aluminum alloy.

32. The multilayer coated metal substrate according to claim 31, wherein the metal substrate comprises an aluminum alloy, and the aluminum alloy comprises 2000, 3000, 4000, 5000, 6000 or 7000 series aluminum alloys.

33. The multilayer coated metal substrate according to claim 31, wherein the aluminum alloy includes 2024 aluminum alloy, 7075 aluminum alloy or 6061 aluminum alloy.

34. The multilayer coated metal substrate according to any one of claims 23 to 30, wherein the metal substrate is covered or uncovered, and if covered, the covering layer may comprise the same or different material as the metal substrate.

35. The multilayer coated metal substrate according to any one of claims 23 to 30, wherein the metal substrate is a clad aluminum alloy, and wherein the cladding layer is aluminum.

36. The multilayer coated metal substrate according to any one of claims 23 to 30, wherein the metal substrate is an aircraft component.

37. The multilayer coated metal substrate according to any one of claims 23 to 30, wherein the curable film-forming adhesive of the second coating comprises a fluoropolymer and / or polyurethane.

38. The multilayer coated metal substrate according to any one of claims 23 to 30, wherein the second coating is a top coating.

39. The multilayer coated metal substrate according to any one of claims 23 to 30, wherein the second coating is a transparent coating.

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