Electrodepositable coating compositions

Abstract

The present invention relates to an electrodepositable coating composition, comprising a film-forming polymer containing an ionic salt group, the film-forming polymer comprising an active hydrogen functional group; a blocked polyisocyanate curing agent comprising a blocking group, wherein at least 30% of the blocking groups, based on the total number of the blocking groups, comprise 1,2-polyol as a blocking agent; and a bismuth catalyst. A coating, a coated substrate, and a method for coating a substrate are also disclosed.

Description

Technical Field

[0001] The present invention relates to an electrodepositable coating composition, a treated substrate and a method of coating a substrate. Background Art

[0002] As a coating application method, electrodeposition involves depositing a film-forming composition onto a conductive substrate under the influence of an applied potential. Compared with non-electrophoretic coating methods, electrodeposition is increasingly popular in the coating industry because it provides higher coating utilization, excellent corrosion resistance and low environmental pollution. Both cationic electrodeposition processes and anionic electrodeposition processes are used commercially. Blocked polyisocyanate curing agents are commonly used in coating compositions that can be electrodeposited to achieve curing of the coating once applied. When external energy such as heating is applied, the blocking agent for reversibly "blocking" the isocyanate groups of the blocked polyisocyanate curing agent is removed, so that the isocyanate groups react with the polymer binder resin and crosslink and cure the coating. Heating is usually used to remove the blocking agent from the blocked isocyanate groups of the blocked polyisocyanate curing agent. Heating requires significant energy costs. The previously unblocked blocked polyisocyanate curing agents at relatively low temperatures are difficult to prepare, and they are toxic or crystalline and difficult to handle. In addition, although catalysts can be used to reduce the curing temperature of coating compositions, tin and lead catalysts are subject to many regulatory restrictions in various countries due to environmental issues. Therefore, there is a need for coating compositions that can be cured at low temperatures using non-tin and non-lead catalysts and blocked polyisocyanate curing agents. Summary of the invention

[0003] The present invention provides an electrodepositable coating composition, which comprises a film-forming polymer containing an ionic salt group, the film-forming polymer comprising an active hydrogen functional group; a blocked polyisocyanate curing agent comprising blocking groups, wherein at least 30% of the blocking groups, based on the total number of blocking groups, comprise 1,2-polyol as the blocking agent; and a bismuth catalyst.

[0004] The present invention also provides a method of coating a substrate comprising electrophoretically applying a coating deposited from an electrodepositable coating composition of the present invention to at least a portion of the substrate.

[0005] The present invention further provides a coating deposited from an electrodepositable coating composition comprising a film-forming polymer containing ionic salt groups, the film-forming polymer comprising active hydrogen functional groups; a blocked polyisocyanate curing agent comprising blocking groups, wherein at least 30% of the blocking groups, based on the total number of blocking groups, comprise 1,2-polyols as blocking agents; and a bismuth catalyst.

[0006] The present invention further provides a substrate coated with a coating deposited from the electrodepositable coating composition of the present invention. DETAILED DESCRIPTION

[0007] The present invention relates to an electrodepositable coating composition, which comprises a film-forming polymer containing ionic salt groups, the film-forming polymer comprising active hydrogen functional groups; a blocked polyisocyanate curing agent comprising blocking groups, wherein at least 20% of the blocking groups, based on the total number of blocking groups, comprise 1,2-polyols as blocking agents; and a bismuth catalyst.

[0008] According to the present invention, the term "electrodepositable coating composition" refers to a composition that can be deposited onto a conductive substrate under the influence of an applied electric potential. As further described herein, the electrodepositable coating composition can be a cationic electrodepositable coating composition or an anionic electrodepositable coating composition.

[0009] Film-forming polymers containing ionic salt groups

[0010] According to the present invention, the coating composition that can be electrodeposited comprises a film-forming polymer containing an ionic salt group. The film-forming polymer containing an ionic salt group can be applied to a substrate by electrodeposition. The film-forming polymer containing an ionic salt group can comprise a film-forming polymer containing a cationic salt group or a film-forming polymer containing an anionic salt group.

[0011] Film-forming polymers containing ionic salt groups may include film-forming polymers containing cationic salt groups. Film-forming polymers containing cationic salt groups can be used in coating compositions that can be electrodeposited by cations. As used herein, the term "film-forming polymers containing cationic salt groups" refers to cationic groups that include at least partially neutralized cationic groups that provide positive charge, such as sulfonium groups and ammonium groups. Film-forming polymers containing cationic salt groups may include active hydrogen functional groups. As described in "Journal of the American Chemical Society", Vol. 49, p. 3181 (1927), the term "active hydrogen" refers to hydrogen that shows activity according to the Zerewitinofftest due to its position in the molecule. Therefore, active hydrogen includes hydrogen atoms connected to oxygen, nitrogen or sulfur, and therefore active hydrogen functional groups include, for example, hydroxyl, thiol, primary amino and / or secondary amino groups (in any combination). The cationic salt group-containing film-forming polymer comprising an active hydrogen functional group may be referred to as an active hydrogen-containing, cationic salt group-containing film-forming polymer.

[0012] Examples of polymers suitable for use as the film-forming polymer containing cationic salt groups in the present invention include, but are not limited to, alkyd polymers, acrylics, polyepoxides, polyamides, polyurethanes, polyureas, polyethers, polyesters, and the like.

[0013] More specific examples of suitable active hydrogen-containing, cationic salt group-containing film-forming polymers include polyepoxide-amine adducts, such as adducts of polyglycidyl ethers of polyhydric phenols (such as bisphenol A) with primary and / or secondary amines, as described in U.S. Pat. No. 4,031,050, at column 3, line 27 to column 5, line 50, U.S. Pat. No. 4,452,963, at column 5, line 58 to column 6, line 66, and U.S. Pat. No. 6,017,432, at column 2, line 66 to column 6, line 26, portions of which are incorporated herein by reference. A portion of the amine reacted with the polyepoxide may be a ketimine of a polyamine, as described in U.S. Pat. No. 4,104,147, at column 6, line 23 to column 7, line 23, the cited portions of which are incorporated herein by reference. Also suitable are ungelled polyepoxide-polyoxyalkylene polyamine resins as described in U.S. Pat. No. 4,432,850 at column 2, line 60 to column 5, line 58, the cited portions of which are incorporated herein by reference. In addition, cationic acrylic resins such as those described in U.S. Pat. Nos. 3,455,806 at column 2, line 18 to column 3, line 61 and 3,928,157 at column 2, line 29 to column 3, line 21, portions of which are incorporated herein by reference, may be used.

[0014] In addition to the resin containing amine salt groups, resin containing quaternary ammonium salt groups can also be used as the film-forming polymer containing cationic salt groups in the present invention. Examples of these resins are resins formed by reacting organic polyepoxides with tertiary amine acid salts. Such resins are described in U.S. Pat. No. 3,962,165, Column 2, Line 3 to Column 11, Line 7; No. 3,975,346, Column 1, Line 62 to Column 17, Line 25, and U.S. Pat. No. 4,001,156, Column 1, Line 37 to Column 16, Line 7, which parts are incorporated herein by reference. Examples of other suitable cationic resins include resins containing tertiary sulfonium salt groups, such as those described in U.S. Pat. No. 3,793,278, Column 1, Line 32 to Column 5, Line 20, which part is incorporated herein by reference. Furthermore, cationic resins that cure via a transesterification mechanism may be used, as described in European Patent Application No. 12463 B1, page 2, line 1 to page 6, line 25, this part of which is incorporated herein by reference.

[0015] Other suitable film-forming polymers containing cationic salt groups include film-forming polymers that can form an electrodepositable coating composition that resists photodegradation. Such polymers include polymers including cationic amine salt groups derived from side chains and / or terminal amino groups, which are disclosed in paragraphs

[0064] to

[0088] of U.S. Patent Application Publication No. 2003 / 0054193A1, which are incorporated herein by reference. Also suitable are resins containing active hydrogen and cationic salt groups derived from polyglycidyl ethers of polyphenols, which are substantially free of aliphatic carbon atoms bonded to more than one aromatic group, which are described in paragraphs

[0096] to

[0123] of U.S. Patent Application Publication No. 2003 / 0054193A1, which are incorporated herein by reference.

[0016] The active hydrogen-containing, cationic salt-containing film-forming polymer is made cationic and water-dispersible by at least partially neutralizing with an acid. Suitable acids include organic acids and inorganic acids. Non-limiting examples of suitable organic acids include formic acid, acetic acid, methanesulfonic acid and lactic acid. Non-limiting examples of suitable inorganic acids include phosphoric acid and sulfamic acid. "Sulfamic acid" means sulfamic acid itself or a derivative thereof, such as sulfamic acid or a derivative thereof having the formula:

[0017]

[0018] wherein R is hydrogen or an alkyl group having 1 to 4 carbon atoms. Mixtures of the above-mentioned acids can also be used in the present invention.

[0019] The degree of neutralization of the film-forming polymer containing cationic salt groups can vary with the specific polymer involved. However, sufficient acid should be used to fully neutralize the film-forming polymer containing cationic salt groups so that the film-forming polymer containing cationic salt groups can be dispersed in an aqueous dispersion medium at room temperature in an amount described herein. For example, the amount of acid used can provide at least 20% of the total theoretical neutralization. Excessive acid exceeding 100% of the total theoretical neutralization required amount can also be used. For example, the amount of acid used to neutralize the film-forming polymer containing cationic salt groups can be ≧0.1% based on the total amine in the film-forming polymer containing active hydrogen and cationic salt groups. Alternatively, the amount of acid used to neutralize the film-forming polymer containing active hydrogen and cationic salt groups can be ≦100% based on the total amine in the film-forming polymer containing active hydrogen and cationic salt groups. The range of the total amount of acid used to neutralize the film-forming polymer containing cationic salt groups can be between any combination of the values ​​stated in the preceding sentence (including the stated values). For example, the total amount of acid used to neutralize the active hydrogen-containing, cationic salt group-containing film-forming polymer may be equal to or greater than 20%, 35%, 50%, 60% or 80% based on the total amines in the cationic salt group-containing film-forming polymer.

[0020] Based on the total weight of the resin solids of the electrodepositable coating composition, the film-forming polymer containing cationic salt groups can be present in the cationic electrodepositable coating composition in an amount of at least 40% by weight, such as at least 50% by weight, such as at least 60% by weight, and can be present in an amount of no more than 90% by weight, such as no more than 80% by weight, such as no more than 75% by weight. Based on the total weight of the resin solids of the electrodepositable coating composition, the film-forming polymer containing cationic salt groups can be present in the cationic electrodepositable coating composition in an amount of 40% to 90% by weight, such as 50% to 80% by weight, such as 60% to 75% by weight.

[0021] Alternatively, the film-forming polymer containing ionic salt groups may include film-forming polymers containing anionic salt groups. As used herein, the term "film-forming polymer containing anionic salt groups" refers to anionic polymers containing at least partially neutralized anionic functional groups (such as carboxylic acid and phosphoric acid groups), and the anionic functional groups give the polymer a negative charge. The film-forming polymer containing anionic salt groups may include active hydrogen functional groups. The film-forming polymer containing anionic salt groups containing active hydrogen functional groups may be referred to as a film-forming polymer containing active hydrogen and anionic salt groups. The film-forming polymer containing anionic salt groups can be used in anionic electrodepositable coating compositions.

[0022] The film-forming polymer containing anionic salt groups may include alkali-solubilized film-forming polymer containing carboxylic acid groups, such as the reaction product or adduct of a drying oil or a semi-drying fatty acid ester with a dicarboxylic acid or anhydride; and the reaction product of a fatty acid ester, an unsaturated acid or anhydride with any other unsaturated modifying material further reacted with a polyol. Also suitable are at least partially neutralized copolymers of hydroxyalkyl esters of unsaturated carboxylic acids, unsaturated carboxylic acids and at least one other ethylenically unsaturated monomer. Another suitable anionic electrodepositable resin includes an alkyd-aminoplast carrier, i.e., a carrier containing an alkyd resin and an amine-aldehyde resin. Another suitable anionic electrodepositable resin composition includes a mixed ester of a resin polyol. Other acid-functional polymers may also be used, such as phosphated polyepoxides or phosphated acrylic polymers. Exemplary phosphated polyepoxides are disclosed in U.S. Patent Application Publication No. 2009-0045071,

[0004] to

[0015] and U.S. Patent Application No. 13 / 232,093,

[0014] to

[0040] , the cited portions of which are incorporated herein by reference. Also suitable are resins containing one or more pendant carbamate functional groups, such as those described in U.S. Patent No. 6,165,338.

[0023] According to the total weight of the resin solids of the electrodepositable coating composition, the film-forming polymer containing anionic salt groups can 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 can be present in an amount of no more than 90% by weight, such as no more than 80% by weight, such as no more than 75% by weight. According to the total weight of the resin solids of the electrodepositable coating composition, the film-forming polymer containing anionic salt groups can be present in an anionic electrodepositable coating composition in an amount of 50% to 90%, such as 55% to 80%, such as 60% to 75%.

[0024] According to the total weight of the resin solids of the electrodepositable coating composition, the film-forming polymer containing ionic salt groups can be present in the electrodepositable coating composition in an amount of at least 40 wt %, such as at least 50 wt %, such as at least 55 wt %, such as at least 60 wt %. According to the total weight of the resin solids of the electrodepositable coating composition, the film-forming polymer containing ionic salt groups can be present in the electrodepositable coating composition in an amount of no more than 90 wt %, such as no more than 80 wt %, such as no more than 75 wt %. According to the total weight of the resin solids of the electrodepositable coating composition, the film-forming polymer containing ionic salt groups can be present in the electrodepositable coating composition in an amount of 40 wt % to 90 wt %, such as 50 wt % to 90 wt %, such as 50 wt % to 80 wt %, such as 55 wt % to 80 wt %, such as 60 wt % to 75 wt %.

[0025] Blocked polyisocyanate curing agent

[0026] According to the present invention, the electrodepositable coating composition of the present invention further comprises a blocked polyisocyanate curing agent.

[0027] As used herein, "blocked polyisocyanate" refers to a polyisocyanate in which at least a portion of the isocyanate groups are blocked by blocking groups introduced by reaction of the free isocyanate groups of the polyisocyanate with a blocking agent. "Blocked" means that the isocyanate groups have reacted with a blocking agent such that the resulting blocked isocyanate groups are stable to active hydrogen at ambient temperature, such as room temperature (about 23°C), but react with active hydrogen in the film-forming polymer at elevated temperatures, such as, for example, between 90°C and 200°C. Thus, a blocked polyisocyanate curing agent comprises a polyisocyanate reacted with one or more blocking agents. As used herein, "blocking agent" refers to a compound comprising functional groups that react with isocyanate groups present on a polyisocyanate, resulting in the remaining portion of the blocking agent being bonded to the isocyanate groups such that the isocyanate groups are stable to active hydrogen functional groups at room temperature (i.e., 23°C). The residual part of the blocking agent combined with the isocyanate group is referred to as "blocking group" in this article, which provides the stability of the isocyanate group to the active hydrogen functional group at room temperature. The blocking group can be identified by reference to the blocking agent, and the blocking group is derived from the blocking agent by reacting with the isocyanate group. The blocking group can be removed under suitable conditions, such as at an elevated temperature, so that a free isocyanate group can be generated from the blocked isocyanate group. Therefore, the reaction with the blocking agent can be reversed at an elevated temperature so that the previously blocked isocyanate group is free to react with the active hydrogen functional group. As used herein, the term "derived from" with respect to the blocking group of the blocked polyisocyanate is intended to refer to the presence of the residue of the blocking agent in the blocking group and is not intended to be limited to the blocking group produced by the reaction of the isocyanate group of the polyisocyanate with the blocking agent. Therefore, the blocking group of the present invention produced by the synthetic route that does not include the direct reaction of the isocyanate group and the blocking agent will still be considered to be "derived from" the blocking agent. Therefore, the term "blocking agent" can also be used to refer to the portion of the blocked polyisocyanate that leaves the blocking group to produce free isocyanate groups during the curing process. As used herein, the term "blocked polyisocyanate curing agent" is collectively referred to as a completely blocked polyisocyanate curing agent and an at least partially blocked polyisocyanate curing agent. As used herein, a "completely blocked polyisocyanate curing agent" refers to a polyisocyanate in which each of the isocyanate groups has been blocked with a blocking group. As used herein, an "at least partially blocked polyisocyanate curing agent" refers to a polyisocyanate in which at least a portion of the isocyanate groups has been blocked with a blocking group, while the remaining isocyanate groups have reacted with a portion of the polymer backbone.

[0028] The blocked polyisocyanate curing agent comprises an isocyanate group that reacts with a reactive group (such as an active hydrogen group) of a film-forming polymer containing an ionic salt group to achieve the curing of the coating composition to form a coating. As used herein, the term "curing", "cured" or similar terms used in combination with the electrodepositable coating composition described herein means that at least a portion of the components of the electrodepositable coating composition are crosslinked to form a coating. In addition, the curing of the electrodepositable coating composition refers to subjecting the composition to a curing condition (such as an elevated temperature) that causes the blocked isocyanate group of the blocked polyisocyanate curing agent to unblock, so as to cause the unblocked isocyanate group of the polyisocyanate curing agent to react with the active hydrogen functional group of the film-forming polymer, and cause the components of the electrodepositable coating composition to crosslink and form a coating that is at least partially cured. The blocking agent removed during the curing process can be removed from the coating film by volatilization. Alternatively, a portion or all of the blocking agent can be retained in the coating film after curing.

[0029] The polyisocyanates that can be used for preparing the blocked polyisocyanate curing agent of the present invention include any suitable polyisocyanates known in the art.Polyisocyanates are organic compounds comprising at least two, at least three, at least four or more isocyanato functional groups, such as two, three, four or more isocyanato functional groups.For example, polyisocyanates can include aliphatic and / or aromatic polyisocyanates.As will be understood, aromatic polyisocyanates will have a nitrogen atom covalently bonded to the isocyanate group of the carbon present in the aromatic group, and aliphatic polyisocyanates can contain an aromatic group indirectly bonded to the isocyanato group by a non-aromatic hydrocarbon group. Aliphatic polyisocyanates may include, for example, (i) alkylene isocyanates such as trimethylene diisocyanate, tetramethylene diisocyanate, pentamethylene diisocyanate, hexamethylene diisocyanate ("HDI"), 1,2-propylene diisocyanate, 1,2-butylene diisocyanate, 2,3-butylene diisocyanate, 1,3-butylene 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"), cyclotrimer of 1,6-hexamethylene diisocyanate (also known as isocyanurate trimer of HDI, available as Desmodur N3300 from Covestro AG). AG) commercially available) and tetramethyl meta-xylylene diisocyanate (available as Commercially available from Allnex SA). Aromatic polyisocyanates can include, for example, (i) arylene isocyanates such as m-phenylene diisocyanate, p-phenylene diisocyanate, 1,5-naphthalene diisocyanate, and 1,4-naphthalene diisocyanate, and (ii) aralkylene isocyanates such as 4,4′-diphenylene methane diisocyanate (“MDI”), 2,4-tolylene diisocyanate, or 2,6-tolylene diisocyanate (“TDI”), or mixtures thereof, 4,4-toluidine diisocyanate, and xylylene diisocyanate. Triisocyanates such as triphenylmethane-4,4',4"-triisocyanate, 1,3,5-triisocyanatobenzene and 2,4,6-triisocyanatotoluene; tetraisocyanates such as 4,4'-diphenyldimethylmethane-2,2',5,5'-tetraisocyanate; and polymeric polyisocyanates such as tolylene diisocyanate dimer and trimer may also be used. Blocked polyisocyanate curing agents may also include polymeric polyisocyanates such as polymeric HDI, polymeric MDI, polymeric isophorone diisocyanate, etc. The curing agent may also include blocked trimers of hexamethylene diisocyanate, which may be used as Desmodur Commercially available from Covestro AG. Mixtures of polyisocyanate curing agents may also be used.

[0030] As mentioned above, the isocyanate groups of the polyisocyanate are blocked by the blocking agent so that the blocked polyisocyanate curing agent contains the blocking group. The blocking group can be formed by reacting the isocyanate group with the blocking agent in a molar ratio. For example, the isocyanate group can react with the isocyanate group and the blocking agent in a 1:1 molar ratio so that the isocyanate group is theoretically 100% blocked by the blocking agent. Alternatively, the molar ratio of the isocyanate group to the blocking agent can be such that the isocyanate group or the blocking agent is excessive. The blocking group itself is a carbamate group containing the residue of the isocyanate group and the blocking agent.

[0031] According to the present invention, the capping agent may include 1,2-polyols. The 1,2-polyols will react with the isocyanato groups of the polyisocyanates to form capping groups. Based on the total number of capping groups, the 1,2-polyols may include at least 30%, such as at least 35%, such as at least 40%, such as at least 45%, such as at least 50%, such as at least 55%, such as at least 60%, such as at least 65%, such as at least 70%, such as at least 75%, such as at least 80%, such as at least 85%, such as at least 90%, such as at least 95%, such as at least 99%, such as 100%. The 1,2-polyol may contain no more than 100% of the blocked polyisocyanate curing agent's blocked groups, such as no more than 99%, such as no more than 95%, such as no more than 90%, such as no more than 85%, such as no more than 80%, such as no more than 75%, such as no more than 70%, such as no more than 65%, such as no more than 60%, such as no more than 55%, such as no more than 50%, such as no more than 45%, such as no more than 40%, such as no more than 35%, such as no more than 30%, based on the total number of blocked groups.The 1,2-polyol may comprise 30% to 100% of the blocked polyisocyanate curing agent's blocked groups, such as 30% to 100%, such as 35% to 100%, such as 40% to 100%, such as 45% to 100%, such as 50% to 100%, such as 55% to 100%, such as 60% to 100%, 65% to 100%, such as 70% to 100%, such as 75% to 100%, such as 80% to 100%, 85% to 100%, such as 90% to 100%, such as 95% to 100%, such as 30% to 95%, such as 35% to 95%, such as 40% to 95%, such as 45% to 95%, such as 50% to 95%, such as 55% to 100%, such as 60% to 100%, 65% to 100%, such as 70% to 100%, such as 75% to 100%, such as 80% to 100%, 85% to 100%, such as 90% to 100%, such as 95% to 100%, such as 30% to 95%, such as 35% to 95%, such as 40% to 95%, such as 45% to 95%, such as 50% to 95%, such as 55% to 95%, such as 60% to 100%, 65% to 100%, % to 95%, such as 70% to 95%, such as 75% to 95%, such as 80% to 95%, 85% to 95%, such as 90% to 95%, such as 30% to 90%, such as 35% to 90%, such as 40% to 90%, such as 45% to 90%, such as 50% to 90%, such as 55% to 90%, such as 60% to 90%, 65% to 90%, such as 70% to 90%. % to 90%, such as 75% to 90%, such as 80% to 90%, 85% to 90%, such as 30% to 85%, such as 35% to 85%, such as 40% to 85%, such as 45% to 85%, such as 50% to 85%, such as 55% to 85%, such as 60% to 85%, 65% to 85%, such as 70% to 85%, such as 75% to 85%, such as 80% to 85%, such as 30% to 80%, such as 35% to 80%, such as 40% to 80%, such as 45% to 80%, such as 50% to 80%, such as 55% to 80%, such as 60% to 80%, 65% to 80%, such as 70% to 80%, such as 75% to 80%, such as 30% to 75%, such as 35% to 75%, such as 40% to 75 ... % to 75%, such as 50% to 75%, such as 55% to 75%, such as 60% to 75%, 65% to 75%, such as 70% to 75%, such as 30% to 70%, such as 35% to 70%, such as 40% to 70%, such as 45% to 70%, such as 50% to 70%, such as 55% to 70%, such as 60% to 70%, 65% to 70%, such as 30 % to 65%, such as 35% to 65%, such as 40% to 65%, such as 45% to 65%, such as 50% to 65%, such as 55% to 65%, such as 60% to 65%, such as 30% to 60%, such as 35% to 60%, such as 40% to 60%, such as 45% to 60%, such as 50% to 60%, such as 55% to 60%, such as 30% to 55%, such as 35% to 55%, such as 40% to 55%, such as 45% to 55%, such as 50% to 55%, such as 30% to 50%, such as 35% to 50%, such as 40% to 50%, such as 45% to 50%, such as 30% to 45%, such as 35% to 45%, such as 40% to 45%, such as 30% to 40%, such as 35% to 40%, such as 30% to 35%.As used herein, the percentage of the blocking group of the blocked polyisocyanate curing agent relative to the blocking agent refers to the molar percentage of the isocyanate group blocked by the blocking agent divided by the total number of isocyanate groups actually blocked, i.e., the total number of blocking groups. The percentage of blocking groups can be determined by dividing the total moles of blocking groups blocked with a specific blocking agent by the total moles of blocking groups of the blocked polyisocyanate curing agent and multiplying by 100. It can also be expressed as the ratio of the equivalent of the blocking agent to the total equivalent of isocyanate groups from the polyisocyanate, and the percentage and equivalent can be converted and used interchangeably (for example, 40% of the total blocking group is the same as 4 / 10 equivalents). For clarity, when referring to the blocking group blocked with a blocking agent, the blocking group does not need to be strictly derived from the reaction of the isocyanate group with the blocking agent, and can be prepared by any synthetic route discussed below.

[0032] The 1,2-polyol may include 1,2-alkanediol. Non-limiting examples of 1,2-alkanediol include ethylene glycol, propylene glycol, 1,2-butanediol, 1,2-pentanediol, 1,2-hexanediol, 1,2-heptanediol, 1,2-octanediol, glycerol esters or ethers having 1,2-dihydroxy functional groups, and the like, and combinations thereof may be included.

[0033] As described above, the isocyanate groups of the polyisocyanate are blocked with a blocking agent, so that the blocked polyisocyanate curing agent comprises a blocking group to produce a urethane-containing compound. Therefore, the blocked polyisocyanate curing agent can be represented by the resulting structure produced after the isocyanate group and the blocking agent react, and the blocked polyisocyanate curing agent can comprise the following structure:

[0034]

[0035] wherein R is hydrogen or a substituted or unsubstituted alkyl group containing 1 to 8 carbon atoms, such as 1 to 6 carbon atoms, and wherein the substituted alkyl group optionally contains an ether or ester functionality.

[0036] Although the blocked polyisocyanate curing agent is generally disclosed as being produced by the reaction of an isocyanate group with a blocking agent, it should be understood that any synthetic route that can produce the blocked polyisocyanate curing agent of the above structure can be used to produce the blocked polyisocyanate curing agent of the present invention. For example, as shown in the following reaction scheme, the isocyanate group of the polyisocyanate (the remaining portion of the polyisocyanate is referred to as "X") can react with the hydroxyl group of the hydroxyl functional compound and the epoxy functional compound, and then the resulting epoxy group reacts with the hydroxyl-containing compound (where R is an alkyl group).

[0037]

[0038] In addition to 1,2-polyols, the blocked polyisocyanate may optionally further include a co-capping agent. The co-capping agent may include any suitable capping agent. The co-capping agent may include aliphatic, alicyclic or aromatic alkyl monoalcohols 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 phenylcarbinol and methylphenylcarbinol; and phenolic compounds such as phenol itself and substituted phenols, wherein the substituents do not affect the coating operation, such as cresol and nitrophenol. Glycol ethers and diol amines may 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. Other co-capping agents include 1,3-alkanediols, such as, for example, 1,3-butanediol; benzyl alcohols, such as benzyl alcohol; allyl alcohols, such as allyl alcohol; caprolactam; dialkylamines, such as dibutylamine; other diols, triols, or polyols; and mixtures thereof.

[0039] Based on the total number of blocking groups, the co-blocking agent may contain at least 1% of the blocking groups of the blocked polyisocyanate curing agent, such as at least 5%, such as at least 10%, such as at least 15%, such as at least 20%, such as at least 25%, such as at least 30%, such as at least 45%, such as at least 50%, such as at least 55%, such as at least 60%, such as at least 65%, such as 70%. Based on the total number of blocking groups, the co-blocking agent may contain no more than 70%, such as no more than 65%, such as no more than 60%, such as no more than 55%, such as no more than 50%, such as no more than 45%, such as no more than 40%, such as no more than 35%, such as no more than 30%, such as no more than 25%, such as no more than 20%, such as no more than 15%, such as no more than 10%, such as no more than 5%, such as no more than 1%.Based on the total number of capping groups, the co-capping agent can comprise 1% to 70%, such as 5% to 70%, such as 10% to 70%, such as 15% to 70%, such as 20% to 70%, such as 25% to 70%, such as 30% to 70%, such as 35% to 70%, such as 40% to 70%, such as 45% to 70%, such as 50% to 70%, such as 55% to 70%, such as 60% to 70%, such as 65% to 70%, such as 1% to 65%, such as 5% to 65%, such as 10% to 65%, such as 15% to 65%, such as 20% to 65%, such as 25% to 65%, such as 30% to 65%, such as 35% to 65%, such as 40% to 65%, such as 45% to 65%, such as 50% to 70%, to 65%, such as 55% to 65%, such as 60% to 65%, such as 1% to 60%, such as 5% to 60%, such as 10% to 60%, such as 15% to 60%, such as 20% to 60%, such as 25% to 60%, such as 30% to 60%, such as 35% to 60%, such as 40% to 60%, such as 45% to 60%, such as 50% to 60%, such as 55% to 60%, such as 1% to 55%, such as 5% to 55%, such as 10% to 55%, such as 15% to 55%, such as 20% to 55%, such as 25% to 55%, such as 30% to 55%, such as 35% to 55%, such as 40% to 55%, such as 45% to 55%, such as 50% to 55%, such as 1% to 50%, such as 5% to 50%, such as 10% to 50%, such as 15% to 50%, such as 20% to 50%, such as 25% to 50%, such as 30% to 50%, such as 35% to 50%, such as 40% to 50%, such as 45% to 50%, such as 1% to 45%, such as 5% to 45%, such as 10% to 45%, such as 15% to 45%, such as 20% to 45%, such as 25% to 45%, such as 30% to 45%, such as 35% to 45%, such as 40% to 45%, such as 1% to 40%, such as 5% to 40%, such as 10% to 40%, such as 15% to 40%, such as 20% to 40%, such as 25% to 40%, such as 30% to 40%, such as 35% to 40%, such as 1% to 35%, such as 5% to 35%, such as 10% to 35%, such as 15% to 35%, such as 20% to 35%, such as 25% to 35%, such as 30% to 35%, such as 1% to 30%, such as 5% to 30%, such as 10% to 30%, such as 15% to 30%, such as 20% to 30%, such as 25% to 30%, such as 1% to 25%, such as 5% to 25%, such as 10% to 25%, such as 15% to 25%, such as 20% to 25%, such as 1% to 20%, such as 5% to 20%, such as 10% to 20%, such as 15% to 20%, such as 1% to 15%, such as 5% to 15%, such as 10% to 15%, such as 1% to 10%, such as 5% to 10%, such as 1% to 5.

[0040] The blocked polyisocyanate curing agent may be substantially free of, substantially free of, or completely free of end-capping groups comprising polyester diol end-capping agents, which are formed by the reaction of ethylene glycol, propylene glycol, or 1,4-butanediol with oxalic acid, succinic acid, adipic acid, suberic acid, or sebacic acid. Based on the total number of end-capping groups, if such groups are present in an amount of 3% or less, the blocked polyisocyanate is substantially free of end-capping groups comprising polyester diols. Based on the total number of end-capping groups, if such groups are present in an amount of 1% or less, the blocked polyisocyanate is substantially free of end-capping groups comprising polyester diols. Based on the total number of end-capping groups, if such groups do not exist (i.e., 0%), the blocked polyisocyanate is completely free of end-capping groups comprising polyester diols.

[0041] The curing agent may be present in the cationic electrodepositable coating composition in an amount of at least 10 wt %, such as at least 20 wt %, such as at least 25 wt %, based on the total weight of the resin solids of the electrodepositable coating composition, and may be present in an amount of no more than 60 wt %, such as no more than 50 wt %, such as no more than 40 wt %. Based on the total weight of the resin solids of the electrodepositable coating composition, the curing agent may be present in the cationic electrodepositable coating composition in an amount of 10 wt % to 60 wt %, such as 20 wt % to 50 wt %, such as 25 wt % to 40 wt %.

[0042] Based on the total weight of the resin solids of the electrodepositable coating composition, the curing agent can be present in the anionic electrodepositable coating composition in an amount of at least 10 wt %, such as at least 20 wt %, such as at least 25 wt %, and can be present in an amount of no more than 50 wt %, such as no more than 45 wt %, such as no more than 40 wt %. Based on the total weight of the resin solids of the electrodepositable coating composition, the curing agent can be present in an anionic electrodepositable coating composition in an amount of 10 wt % to 50 wt %, such as 20 wt % to 45 wt %, such as 25 wt % to 40 wt %.

[0043] Bismuth Catalyst

[0044] According to the present invention, the electrodepositable coating composition of the present invention comprises a bismuth catalyst.

[0045] As used herein, the term "bismuth catalyst" refers to a catalyst that contains bismuth and catalyzes the transurethanation reaction, and specifically catalyzes the deblocking of the blocked groups of a blocked polyisocyanate curing agent.

[0046] The bismuth catalyst may comprise a soluble bismuth catalyst. As used herein, a "soluble" or "solubilized" bismuth catalyst is a catalyst in which at least 35% of the bismuth catalyst dissolves in an aqueous medium having a pH in the range of 4 to 7 at room temperature (e.g., 23° C.). The soluble bismuth catalyst may provide solubilized bismuth metal in an amount of at least 0.04% by weight, based on the total weight of the electrodepositable coating composition.

[0047] Alternatively, the bismuth catalyst may comprise an insoluble bismuth catalyst. As used herein, an "insoluble" bismuth catalyst is a catalyst in which less than 35% of the catalyst dissolves in an aqueous medium in the pH range of 4 to 7 at room temperature (e.g., 23° C.). The insoluble bismuth catalyst may provide solubilized bismuth metal in an amount of less than 0.04 wt %, based on the total weight of the electrodepositable coating composition.

[0048] The percentage of solubilized bismuth catalyst present in the composition can be determined using ICP-MS to calculate the total amount of bismuth metal (ie, soluble and insoluble) and the total amount of solubilized bismuth metal, and using these measurements to calculate the percentage.

[0049] The bismuth catalyst may comprise a bismuth compound and / or complex.

[0050] The bismuth catalyst may, for example, comprise colloidal bismuth oxide or hydroxide, a bismuth compound complex, such as, for example, a bismuth chelate, or a bismuth salt of an inorganic or organic acid, wherein the term "bismuth salt" includes not only salts comprising a bismuth cation and an acid anion, but also bismuth oxysalts.

[0051] Examples of inorganic or organic acids from which bismuth salts can be derived are hydrochloric acid, sulfuric acid, nitric acid, inorganic or organic sulfonic acids, carboxylic acids (for example formic acid or acetic acid), aminocarboxylic acids and hydroxycarboxylic acids, such as lactic acid or dimethylolpropionic acid.

[0052] Non-limiting examples of bismuth salts are aliphatic hydroxycarboxylic acid bismuth salts, such as bismuth lactate salts or dimethylolpropionate bismuth salts, such as bismuth lactate or dimethylolpropionate bismuth; bismuth subnitrate; bismuth sulfamate salts; bismuth hydroxysulfonate salts, such as alkylsulfonates, including bismuth methanesulfonate salts, such as bismuth methanesulfonate. Further non-limiting examples of bismuth compounds or complex catalysts include bismuth oxide, bismuth carboxylates, bismuth sulfamate, bismuth sulfonate, and combinations thereof.

[0053] The bismuth catalyst may be present in an amount of at least 0.01 wt %, such as at least 0.1 wt %, such as at least 0.2 wt %, such as at least 0.5 wt %, such as at least 1 wt %, such as 1 wt % of bismuth metal, based on the total resin solids weight of the composition. The bismuth catalyst may be present in an amount of no more than 3 wt %, such as no more than 1.5 wt %, such as no more than 1 wt % of bismuth metal, based on the total resin solids weight of the composition. The bismuth catalyst may be present in an amount of 0.01 wt % to 3 wt %, such as 0.1 wt % to 1.5 wt %, such as 0.2 wt % to 1 wt %, such as 0.5 wt % to 3 wt %, such as 0.5 wt % to 1.5 wt %, such as 0.5 wt % to 1 wt %, such as 1 wt % to 3 wt %, such as 1 wt % to 1.5 wt %, based on the total resin solids weight of the composition.

[0054] Based on the total weight of the electrodepositable coating composition, the bismuth catalyst can be present in an amount such that the amount of the solubilized bismuth metal can be at least 0.04 wt %, such as at least 0.06 wt %, such as at least 0.07 wt %, such as at least 0.08 wt %, such as at least 0.09 wt %, such as at least 0.10 wt %, such as at least 0.11 wt %, such as at least 0.12 wt %, such as at least 0.13 wt %, such as at least 0.14 wt %, or more. Based on the total weight of the electrodepositable coating composition, the bismuth catalyst can be present in an amount such that the amount of the solubilized bismuth metal does not exceed 0.30 wt %.

[0055] The bismuth catalyst can be present in an amount such that the amount of solubilized bismuth metal can be at least 0.22 wt %, such as at least 0.30 wt %, such as at least 0.34 wt %, such as at least 0.40 wt %, such as at least 0.45 wt %, such as 0.51 wt %, such as at least 0.56 wt %, such as at least 0.62 wt %, such as at least 0.68 wt %, such as at least 0.73 wt %, such as at least 0.80 wt %, or more, based on the total weight of resin solids.

[0056] It has been surprisingly found that an electrodepositable coating composition comprising a blocked polyisocyanate curing agent containing a blocking group and a bismuth catalyst produces a synergistic curing effect, wherein at least 30% of the blocking groups, based on the total number of blocking groups, comprise 1,2-polyols as blocking agents. For example, when measured by the double rub test method (as defined in the Examples section below), the electrodepositable coating composition of the present invention can be cured at a temperature of less than 150°C, such as 140°C or less (T 固化For example, when measured by the TGA test method (as defined in the Examples section below), the electrodepositable coating composition of the present invention can be cured at a temperature (T 固化 ).

[0057] For example, the electrodepositable coating composition can be cured at a temperature at least 10°C lower than a comparative electrodepositable coating composition, such as at least 7°C lower than a comparative electrodepositable coating composition, such as at least 5°C lower than a comparative electrodepositable coating composition, such as at least 3°C ​​lower than a comparative electrodepositable coating composition, as measured by the Double Rub Test Method. For example, the electrodepositable coating composition can be cured at a temperature at least 10°C lower than a comparative electrodepositable coating composition, such as at least 7°C lower than a comparative electrodepositable coating composition, such as at least 5°C lower than a comparative electrodepositable coating composition, such as at least 3°C ​​lower than a comparative electrodepositable coating composition, as measured by the TGA Test Method. As used herein, a "comparative electrodepositable coating composition" is a composition having the same ionic film-forming polymer and meeting one of the following conditions: (1) a composition having a blocked polyisocyanate curing agent of the present invention without a catalyst; (2) a composition having a blocked polyisocyanate curing agent of the present invention and a catalyst other than a bismuth catalyst; (3) a composition having a blocked polyisocyanate curing agent of the present invention and a catalyst other than the bismuth catalyst of the present invention (including alternative forms of the bismuth catalyst); or (4) a composition having a blocked polyisocyanate curing agent different from that described herein (i.e., not containing the 1,2-polyol blocking agent in the amount described herein) and with or without a catalyst that may include a bismuth catalyst.

[0058] The bismuth catalyst is provided in an amount of at least 0.5 weight percent bismuth metal based on the total resin solids weight of the composition, and the 1,2-polyol may contain a percentage of capping groups of a blocked polyisocyanate curing agent greater than or equal to [(-1.2x+1.6)*100]% or 30%, whichever is higher, where x is the weight percent of bismuth metal and the percentage of capping groups is based on the total number of capping groups.

[0059] Other components of the electrodepositable coating composition

[0060] In addition to the above-mentioned film-forming polymer containing ionic salt groups, blocked polyisocyanate curing agent and bismuth catalyst, the electrodepositable coating composition according to the present invention may optionally contain one or more other components.

[0061] According to the present invention, the electrodepositable coating composition may optionally contain a co-catalyst to further catalyze the reaction between the blocked polyisocyanate curing agent and the film-forming polymer. Examples of co-catalysts suitable for cationic electrodepositable coating compositions include, but are not limited to, organotin compounds (e.g., dibutyltin oxide and dioctyltin oxide) and salts thereof (e.g., dibutyltin diacetate); other metal oxides (e.g., oxides of cerium and zirconium) and salts thereof; or cyclic guanidines as described in U.S. Pat. No. 7,842,762, Column 1, Line 53 to Column 4, Line 18 and Column 16, Line 62 to Column 19, Line 8, the cited portions of which are incorporated herein by reference. Examples of catalysts suitable for anionic electrodepositable coating compositions include latent acid catalysts, specific examples of which are identified in

[0031] in WO 2007 / 118024, and include, but are not limited to, ammonium hexafluoroantimonate, quaternary ammonium salts of SbF6 (e.g., NA XC-7231), t-ammonium salts of SbF6 (such as NA XC-9223), zinc salt of trifluoromethanesulfonic acid (such as NA A202 and A218), quaternary ammonium salts of trifluoromethanesulfonic acid (such as NA XC-A230) and diethylamine salt of trifluoromethanesulfonic acid (e.g. NA A233), all of which are commercially available from King Industries, USA, 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-toluenesulfonate. Such sulfonates are not as active as free acids in promoting crosslinking. During the curing process, the catalyst can be activated by heating.

[0062] The co-catalyst may be present in the electrodepositable coating composition in an amount of 0.01 wt % to 3 wt %, based on the total weight of resin solids of the electrodepositable coating composition.

[0063] Alternatively, the electrodepositable coating composition may be substantially free of, substantially free of, or completely free of a co-catalyst. As used herein, a coating composition that can be electrodeposited is "substantially free of" a co-catalyst if the co-catalyst is present in an amount less than 0.01% by weight, if present, by the total resin solids weight of the composition. As used herein, a coating composition that can be electrodeposited is "substantially free of" a co-catalyst if the co-catalyst is present in a trace or incidental amount that is insufficient to affect any characteristic of the composition, such as, for example, less than 0.001% by weight, if present, by the total resin solids weight of the composition. As used herein, a coating composition that can be electrodeposited is "substantially free of" a co-catalyst if the co-catalyst is not present in the composition, i.e., 0.000% by weight, by the total resin solids weight of the composition.

[0064] The electrodepositable coating composition may be substantially free, substantially free, or completely free of tin. As used herein, an electrodepositable coating composition is "substantially free" of tin if tin is present in an amount of less than 0.01% by weight, if any, based on the total resin solids weight of the composition. As used herein, an electrodepositable coating composition is "substantially free" of tin if tin is present in a trace or incidental amount that is insufficient to affect any property of the composition, such as, for example, less than 0.001% by weight, if any, based on the total resin solids weight of the composition. As used herein, an electrodepositable coating composition is "completely free" of tin if tin is not present in the composition, i.e., 0.000% by weight, based on the total resin solids weight of the composition.

[0065] The electrodepositable coating composition may be substantially free, substantially free, or completely free of bismuth subnitrate. As used herein, an electrodepositable coating composition is "substantially free" of bismuth subnitrate if bismuth subnitrate is present in an amount of less than 0.01% by weight, if any, based on the total resin solids weight of the composition. As used herein, an electrodepositable coating composition is "substantially free" of bismuth subnitrate if bismuth subnitrate is present in a trace or incidental amount that is insufficient to affect any property of the composition, such as, for example, less than 0.001% by weight, if any, based on the total resin solids weight of the composition. As used herein, an electrodepositable coating composition is "completely free" of bismuth subnitrate if bismuth subnitrate is not present in the composition, i.e., 0.000% by weight, based on the total resin solids weight of the composition.

[0066] The electrodepositable coating composition may be substantially free, substantially free, or completely free of bismuth oxide. As used herein, an electrodepositable coating composition is "substantially free" of bismuth oxide if bismuth oxide is present in an amount of less than 0.01% by weight, if any, based on the total resin solids weight of the composition. As used herein, an electrodepositable coating composition is "substantially free" of bismuth oxide if bismuth oxide is present in a trace or incidental amount that is insufficient to affect any property of the composition, such as, for example, less than 0.001% by weight, if any, based on the total resin solids weight of the composition. As used herein, an electrodepositable coating composition is "completely free" of bismuth oxide if bismuth oxide is not present in the composition, i.e., 0.000% by weight, based on the total resin solids weight of the composition.

[0067] The electrodepositable coating composition may be substantially free, substantially free, or completely free of bismuth silicate. As used herein, an electrodepositable coating composition is "substantially free" of bismuth silicate if bismuth silicate is present in an amount of less than 0.01% by weight, if any, based on the total resin solids weight of the composition. As used herein, an electrodepositable coating composition is "substantially free" of bismuth silicate if bismuth silicate is present in a trace or incidental amount that is insufficient to affect any property of the composition, such as, for example, less than 0.001% by weight, if any, based on the total resin solids weight of the composition. As used herein, an electrodepositable coating composition is "completely free" of bismuth silicate if bismuth silicate is not present in the composition, i.e., 0.000% by weight, based on the total resin solids weight of the composition.

[0068] The electrodepositable coating composition may be substantially free, substantially free, or completely free of bismuth titanate. As used herein, an electrodepositable coating composition is "substantially free" of bismuth titanate if bismuth titanate is present in an amount of less than 0.01% by weight, if any, based on the total resin solids weight of the composition. As used herein, an electrodepositable coating composition is "substantially free" of bismuth titanate if bismuth titanate is present in a trace or incidental amount that is insufficient to affect any property of the composition, such as, for example, less than 0.001% by weight, if any, based on the total resin solids weight of the composition. As used herein, an electrodepositable coating composition is "completely free" of bismuth titanate if bismuth titanate is not present in the composition, i.e., 0.000% by weight, based on the total resin solids weight of the composition.

[0069] The coating composition that can be electrodeposited can be substantially free of, substantially free of, or completely free of bismuth sulfamate. As used herein, by the total resin solids weight of the composition, if bismuth sulfamate is present in an amount of less than 0.01% by weight, if present, then the coating composition that can be electrodeposited is "substantially free of" bismuth sulfamate. As used herein, by the total resin solids weight of the composition, if bismuth sulfamate is present in a trace or incidental amount that is insufficient to affect any characteristic of the composition, such as, for example, less than 0.001% by weight, if present, then the coating composition that can be electrodeposited is "substantially free of" bismuth sulfamate. As used herein, by the total resin solids weight of the composition, if bismuth sulfamate is not present in the composition, i.e., 0.000% by weight, then the coating composition that can be electrodeposited is "completely free of" bismuth sulfamate.

[0070] The electrodepositable coating composition may be substantially free, substantially free, or completely free of bismuth lactate. As used herein, an electrodepositable coating composition is "substantially free" of bismuth lactate if bismuth lactate is present in an amount of less than 0.01% by weight, if any, based on the total resin solids weight of the composition. As used herein, an electrodepositable coating composition is "substantially free" of bismuth lactate if bismuth lactate is present in a trace or incidental amount that is insufficient to affect any property of the composition, such as, for example, less than 0.001% by weight, if any, based on the total resin solids weight of the composition. As used herein, an electrodepositable coating composition is "completely free" of bismuth lactate if bismuth lactate is not present in the composition, i.e., 0.000% by weight, based on the total resin solids weight of the composition.

[0071] According to the present invention, the coating composition that can be electrodeposited can further include other optional ingredients, such as pigment compositions, and if necessary, various additives, such as fillers, antioxidants, biocides, UV light absorbers and stabilizers, hindered amine light stabilizers, defoamers, fungicides, dispersing aids, flow control agents, surfactants, wetting agents, shrinkage control additives or combinations thereof. Alternatively, the coating composition that can be electrodeposited can be completely free of any optional ingredients, i.e., the optional ingredients are not present in the coating composition that can be electrodeposited. The pigment composition can include, for example, iron oxide, lead oxide, strontium chromate, carbon black, coal powder, titanium dioxide, talcum, barium sulfate, and color pigments such as cadmium yellow, cadmium red, chrome yellow. When using pigment, the pigment content of the dispersion can be expressed as a weight ratio of pigment to resin, and can be in the range of 0.03 to 0.6. According to the total weight of the resin solids of the coating composition that can be electrodeposited, the above-mentioned other additives can be each independently present in the coating composition that can be electrodeposited in an amount of 0.01% by weight to 3% by weight.

[0072] According to the present invention, the electrodepositable coating composition may further comprise a plasticizer. The plasticizer may be any suitable plasticizer. The plasticizer may comprise, for example, a polyalkylene glycol, such as polyethylene glycol, polypropylene glycol or polybutylene glycol. The polyalkylene glycol may comprise two secondary hydroxyl functional groups. The plasticizer may have a molecular weight of at least 400 g / mol, such as at least 500 g / mol, such as at least 700 g / mol. The plasticizer may have a molecular weight of no more than 5,000 g / mol, such as no more than 1,000 g / mol, such as no more than 800 g / mol. The plasticizer may have a molecular weight of 400 to 5,000 g / mol, such as 400 to 1,000 g / mol, such as 400 to 800 g / mol, such as 500 to 5,000 g / mol, such as 500 to 1,000 g / mol, such as 500 to 800 g / mol, such as 700 to 5,000 g / mol, such as 700 to 1,000 g / mol, such as 700 to 800 g / mol.

[0073] According to the present invention, the coating composition that can be electrodeposited can include water and / or one or more organic solvents. According to the gross weight of the coating composition that can be electrodeposited, water can be, for example, present in an amount of 40% by weight to 90% by weight, such as 50% by weight to 75% by weight. The example of a suitable organic solvent includes an oxygenated organic solvent, such as the monoalkyl ether containing 1 to 10 carbon atoms in the alkyl group of ethylene glycol, diethylene glycol, propylene glycol and dipropylene glycol, such as the monoethyl ether and monobutyl ether of these glycols. Other examples of water-miscible solvents at least partially include alcohols, such as ethanol, isopropanol, butanol and diacetone alcohol. If used, according to the gross weight of the coating composition that can be electrodeposited, the organic solvent can generally be present in an amount of less than 10% by weight, such as less than 5% by weight. The coating composition that can be electrodeposited can be specifically provided in the form of a dispersion, such as an aqueous dispersion.

[0074] According to the present invention, the total solid content of the electrodepositable coating composition may be at least 1 wt %, such as at least 5 wt %, and may not exceed 50 wt %, such as not more than 40 wt %, such as not more than 20 wt %, based on the total weight of the electrodepositable coating composition. The total solid content of the electrodepositable coating composition may be from 1 wt % to 50 wt %, such as from 5 wt % to 40 wt %, such as from 5 wt % to 20 wt %, based on the total weight of the electrodepositable coating composition. As used herein, "total solids" refers to the non-volatile content of the electrodepositable coating composition, i.e., substances that will not volatilize when heated to 110° C. for 15 minutes.

[0075] Substrate

[0076] According to the present invention, the coating composition that can be electrodeposited can be applied to the substrate electrophoretically. The coating composition that can be electrodeposited by cation can be deposited electrophoretically on any conductive substrate. Suitable substrates include metal substrates, metal alloy substrates and / or metallized substrates, such as nickel-plated plastics. Additionally, the substrate can include non-metallic conductive materials, including composite materials such as materials that include carbon fibers or conductive carbon. According to the present invention, the metal or metal alloy can include cold-rolled steel, hot-rolled steel, steel coated with zinc metal, zinc compounds or zinc alloys, such as electrogalvanized steel, hot-dip galvanized steel, alloyed hot-dip galvanized steel and steel coated with zinc alloys. Aluminum alloys of 2XXX, 5XXX, 6XXX or 7XXX series and clad aluminum alloys and cast aluminum alloys of A356 series can also be used as substrates. Magnesium alloys of AZ31B, AZ91C, AM60B or EV31A series can also be used as substrates. The substrate used in the present invention can also include titanium and / or titanium alloys. Other suitable non-ferrous metals include copper and magnesium and alloys of these materials. Suitable metal substrates for use in the present invention include those commonly used in assembling vehicle bodies (such as, but not limited to, doors, body panels, trunk lids, roof panels, hoods, roofs and / or longitudinal beams, rivets, landing gear components, and / or skins for aircraft), vehicle frames, vehicle parts, motorcycles, wheels, industrial structures and components, such as electrical appliances, including washers, dryers, refrigerators, stoves, dishwashers, etc., agricultural equipment, lawn and garden equipment, air conditioning units, heat pump units, lawn furniture, and other articles. As used herein, "vehicle" or variations thereof include, but are not limited to, civil, commercial and military aircraft and / or land vehicles, such as automobiles, motorcycles and / or trucks. The metal substrate can also be in the form of, for example, metal sheets or manufactured parts. It should also be understood that the substrate can be pretreated with a pretreatment solution that includes a zinc phosphate pretreatment solution, such as the zinc phosphate pretreatment solutions described in U.S. Pat. Nos. 4,793,867 and 5,588,989, or a zirconium-containing pretreatment solution, such as the zirconium-containing pretreatment solutions described in U.S. Pat. Nos. 7,749,368 and 8,673,091.

[0077] In an example, the substrate may include a three-dimensional component formed by an additive manufacturing process such as selective laser melting, electron beam melting, directed energy deposition, binder jetting, metal extrusion, etc. In an example, the three-dimensional component may be a metal and / or resin component.

[0078] Coating method, coating and coated substrate

[0079] The present invention also relates to a method for coating a substrate (such as any of the above-mentioned conductive substrates). According to the present invention, such a method may include electrophoretically applying an electrodepositable coating composition as described above to at least a portion of the substrate and curing the coating composition to form an at least partially cured coating on the substrate. According to the present invention, the method may include (a) electrophoretically depositing the electrodepositable coating composition of the present invention onto at least a portion of the substrate and (b) heating the coated substrate to a temperature and for a time sufficient to cure the electrodeposited coating on the substrate. According to the present invention, the method may optionally further include (c) directly applying one or more pigmented coating compositions and / or one or more non-pigmented coating compositions to the at least partially cured electrodeposited coating to form a top coating on at least a portion of the at least partially cured electrodeposited coating, and (d) heating the coated substrate of step (c) to a temperature and for a time sufficient to cure the top coating.

[0080] According to the present invention, the composition can be deposited on a conductive substrate by contacting the coating composition of the present invention with a conductive cathode and a conductive anode, wherein the surface to be coated is a cathode. After contacting the composition, when enough voltages are applied between the electrodes, the adhesion film of the coating composition is deposited on the cathode. The conditions for electrodeposition are similar to the conditions used in the electrodeposition of other types of coatings. The voltage applied can vary and can be, for example, as low as one volt to as high as several thousand volts, such as between 50 volts and 500 volts. The current density can be between 0.5 ampere and 15 amperes per square foot, and tends to reduce during the electrodeposition, which shows that an insulating film has been formed.

[0081] Once the cationic electrodepositable coating composition is electrodeposited on at least a portion of the conductive substrate, the coated substrate is heated to a temperature and 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 the coating refers to forming the coating by subjecting the coating composition to curing conditions, wherein the curing conditions cause at least a portion of the reactive groups of the components of the coating composition to chemically react to form the coating. As described above, the electrodepositable coating composition can be cured at surprisingly low temperatures. The coated substrate can be heated to a temperature in the range of 250°F to 450°F (121.1°C to 232.2°C), such as 275°F to 400°F (135°C to 204.4°C), such as 284°F to 360°F (140°C to 180°C), such as less than 302°F (150°C), such as less than 284°F (140°C). The curing time can depend on the curing temperature and other variables, such as the film thickness of the electrodeposition coating, the content and type of the catalyst present in the composition, etc. For purposes of the present invention, all that is necessary is that the time is sufficient to achieve the curing of the coating on the substrate. For example, the curing time can range from 10 to 60 minutes, such as 20 to 40 minutes. The thickness of the resulting cured electrodeposition coating can range from 15 to 50 microns.

[0082] According to the present invention, the composition can be deposited on a conductive substrate by contacting the coating composition of the present invention with a conductive cathode and a conductive anode, wherein the surface to be coated is a cathode. After contacting the composition, when enough voltages are applied between the electrodes, the adhesion film of the coating composition is deposited on the anode. The conditions for electrodeposition are similar to the conditions used in the electrodeposition of other types of coatings. The voltage applied can vary and can be, for example, as low as one volt to as high as several thousand volts, such as between 50 volts and 500 volts. The current density can be between 0.5 ampere and 15 amperes per square foot, and tends to reduce during the electrodeposition, which shows that an insulating film has been formed.

[0083] Once the anionic electrodepositable coating composition is electrodeposited on at least a portion of the conductive substrate, the coated substrate can be heated to a temperature and 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 the coating refers to forming the coating by subjecting the coating composition to curing conditions, which chemically react at least a portion of the reactive groups of the components of the coating composition to form the coating. As described above, the electrodepositable coating composition can be cured at surprisingly low temperatures. The coated substrate can be heated to a temperature in the range of 200°F to 450°F (93°C to 232.2°C), such as 275°F to 400°F (135°C to 204.4°C), such as 284°F to 360°F (140°C to 180°C), such as less than 302°F (150°C), such as less than 284°F (140°C). The curing time can depend on the curing temperature as well as other variables, such as the film thickness of the electrodeposited coating, the content and type of the catalyst present in the composition, etc. For purposes of the present invention, all that is necessary is that the time is sufficient to achieve the curing of the coating on the substrate. For example, the curing time may range from 10 to 60 minutes, such as 20 to 40 minutes. The thickness of the resulting cured electrodeposition coating may range from 15 to 50 microns.

[0084] If desired, the electrodepositable coating compositions of the present invention can also be applied to substrates using non-electrophoretic coating application techniques such as flow coating, dipping, spraying and roller coating. For non-electrophoretic coating applications, the coating compositions can be applied to conductive substrates as well as non-conductive substrates such as glass, wood and plastic.

[0085] The present invention further relates to coatings formed by at least partially curing the electrodepositable coating compositions described herein.

[0086] The present invention further relates to a substrate at least partially coated with an electrodepositable coating composition as described herein in an at least partially cured state.

[0087] Multilayer coating composites

[0088] The electrodepositable coating composition of the present invention can be used for electrophoretic coating, which is a part of a multilayer coating composite material comprising a substrate with various coatings. The coating may include a pretreatment layer, such as a phosphate layer (e.g., a zinc phosphate layer), an electrophoretic coating produced by the electrodepositable coating composition of the present invention, and a suitable top coating (e.g., a base coating, a clear coating, a colored single coating, and a color plus a transparent composite composition). It should be understood that suitable top coatings include any coatings in those coatings known in the art, and each independently can be water-borne, solvent-based, in the form of solid particles (i.e., a powder coating composition) or in the form of a powder slurry. The top coating generally comprises a film-forming polymer, a cross-linking material, and one or more pigments (if it is a colored base coating or a single coating). According to the present invention, a primer layer is placed between the electrophoretic coating and the base coating. According to the present invention, one or more top coatings are applied to a substantially uncured bottom layer. For example, a clear coating can be applied to at least a portion of a substantially uncured base coating (wet-on-wet), and two layers can be cured simultaneously in a downstream process.

[0089] In addition, the top coating can be applied directly to the electrodepositable coating. In other words, the substrate lacks a primer layer. For example, the base coating can be applied directly to at least a portion of the electrodepositable coating.

[0090] It will also be understood that the topcoat can be applied to the bottom layer despite the fact that the bottom layer has not yet been fully cured. For example, a clearcoat layer can be applied to the basecoat layer even if the basecoat layer has not been subjected to a curing step. The two layers can then be cured during a subsequent curing step, thereby eliminating the need to separately cure the basecoat layer and the clearcoat layer.

[0091] According to the present invention, other ingredients (such as coloring agents and fillers) can be present in various coating compositions that produce topcoat. Any suitable coloring agents and fillers can be used. For example, coloring agents can be added to coatings in any suitable form (such as discrete particles, dispersions, solutions and / or flakes). Single coloring agents or mixtures of two or more coloring agents can be used in coatings of the present invention. It should be noted that coloring agents can exist in a certain layer of multilayer composite materials with enough amounts to give desired characteristics, vision and / or color effects in general.

[0092] Example colorants include pigments, dyes and colorants, such as those used in the coatings industry and / or listed in the Dry Color Manufacturers Association (DCMA), and special effect compositions. Colorants can include, for example, finely divided solid powders that are insoluble but wettable under the conditions of use. Colorants can be organic or inorganic and can be agglomerated or non-agglomerated. Colorants can be incorporated into the coating by grinding or simple mixing. Colorants can be incorporated by grinding into the coating using a grinding vehicle (such as an acrylic grinding vehicle), the use of which is familiar to those skilled in the art.

[0093] Example pigments and / or pigment compositions include, but are not limited to, carbazole dioxazine crude pigments, azo, monoazo, disazo, naphthol AS, salts (salt lakes), benzimidazolone, condensates, metal complexes, isoindolinone, isoindolinone and polycyclic phthalocyanine, quinacridone, perylene, perinone, diketopyrrolopyrrole, thioindigo, anthraquinone, indanthrone, anthrapyrimidine, flavonanthrone, pyranthrone, anthraquinone, dioxazine, triaryl carbocyanine, quinophthalone pigment, diketopyrrolopyrrole 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" can be used interchangeably.

[0094] Example dyes include, but are not limited to, those solvent-based 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, thiazine, azo, indigo, nitro, nitroso, oxazine, phthalocyanine, quinoline, stilbene and triphenylmethane.

[0095] 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., CHARISMACOLORANTS, and MAXITONER INDUSTRIAL COLORANTS, commercially available from the Precision Dispersions Division of Eastman Chemical, Inc.

[0096] Colorants can be in the form of dispersions, including but not limited to nanoparticle dispersions. Nanoparticle dispersions can include one or more highly dispersed nanoparticle colorants and / or colorant particles that produce desired visible colors and / or opacity and / or visual effects. Nanoparticle dispersions can include colorants, such as pigments or dyes with a particle size less than 150nm, such as less than 70nm or less than 30nm. Nanoparticles can be produced by milling raw organic or inorganic pigments with grinding media with a particle size less than 0.5mm. Example nanoparticle dispersions and their manufacturing methods are determined in U.S. Patent No. 6,875,800B2, which is incorporated herein by reference. Nanoparticle dispersions can also be produced by crystallization, precipitation, gas phase condensation and chemical abrasion (i.e., partial dissolution). In order to minimize the re-agglomeration of nanoparticles in the coating, resin-coated nanoparticle dispersions can be used. As used herein, "resin-coated nanoparticle dispersions" refer to the continuous phase of fine "composite microparticles" dispersed as a resin coating on nanoparticles and nanoparticles. Examples of dispersions of resin-coated nanoparticles and methods for making the same are described in U.S. Patent Application No. 10 / 876,031, filed June 24, 2004, which is incorporated herein by reference, and U.S. Provisional Patent Application No. 60 / 482,167, filed June 24, 2003, which is also incorporated herein by reference.

[0097] According to the present invention, the special effect composition that can be used in one or more layers in the multilayer coating composite material includes pigments and / or compositions that produce one or more appearance effects, such as reflection, pearlescence, metallic luster, phosphorescence, fluorescence, photochromism, photosensitivity, thermochromism, iridescence and / or color change. Additional special effect compositions can provide other perceptible characteristics, such as reflectivity, opacity or texture. For example, the special effect composition can produce color shift, so that when the coating is viewed from different angles, the color of the coating changes. Example color effect compositions are determined in U.S. Patent No. 6,894,086, which is incorporated herein by reference. Additional color effect compositions can include transparent coated mica and / or synthetic mica, coated silica, coated aluminum oxide, transparent liquid crystal pigments, liquid crystal coatings and / or any composition, wherein interference comes from the refractive index difference within the material rather than because of the refractive index difference between the material surface and the air.

[0098] According to the present invention, photosensitive compositions and / or photochromic compositions can be used in many layers of a multilayer composite material, and the color of the photosensitive compositions and / or photochromic compositions can be reversibly changed when exposed 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, the molecular structure changes and the changed structure presents a new color that is different from the original color of the composition. When the radiation exposure is removed, the photochromic and / or photosensitive composition can be restored to a static state, wherein the original color of the composition is restored. For example, the photochromic and / or photosensitive composition may be colorless in a non-excited state and present a color in an excited state. The complete color change can occur within a few milliseconds to several minutes (such as 20 seconds to 60 seconds). Example photochromic and / or photosensitive compositions include photochromic dyes.

[0099] According to the present invention, the photosensitive composition and / or photochromic composition can be associated with a polymeric material of a polymeric and / or polymerizable component and / or at least partially bound to the polymeric material of the polymeric and / or polymerizable component, such as by covalent bonding. Unlike some coatings in which the photosensitive composition can migrate out of the coating and crystallize into the substrate, the migration out of the coating of the photosensitive composition and / or photochromic composition associated with and / or at least partially bound to the polymeric and / or polymerizable component according to the present invention is minimal. Examples of photosensitive compositions and / or photochromic compositions and methods for making them are identified in U.S. Patent Application No. 10 / 892,919 filed on July 16, 2004 and incorporated herein by reference.

[0100] As used herein, the term "resin solids" includes the film-forming polymer containing ionic salt groups, the blocked polyisocyanate curing agent, and any additional water-dispersible, non-pigmented components present in the electrodepositable coating composition.

[0101] As used herein, the term "polymer" encompasses, but is not limited to, oligomers and both homopolymers and copolymers.

[0102] As used herein, unless otherwise defined, the term "substantially free" means that a component, if present, is present in an amount of less than 5 weight percent, based on the total weight of the slurry composition.

[0103] As used herein, unless otherwise defined, the term "substantially free" means that a component, if present, is present in an amount of less than 1 wt %, based on the total weight of the slurry composition.

[0104] As used herein, unless otherwise defined, the term “completely free of” means that a component is not present in the slurry composition, ie, 0.00 wt %, based on the total weight of the slurry composition.

[0105] For the purpose of this detailed description, it should be understood that the present invention may take alternative variations and step sequences except where explicitly stated to the contrary. In addition, except in any operating examples, or where otherwise specified, all numerals used in the specification and claims to indicate, for example, the quantity of ingredients should be understood to be modified by the term "about" in all cases. Therefore, unless otherwise indicated, the numerical parameters set forth in the following specification and the appended claims are approximate values ​​that can be changed according to the desired properties to be obtained by the present invention. At least, and without attempting to limit the application of the doctrine of equivalents to the scope of the claims, each numerical parameter should at least be interpreted in accordance with the number of reported significant digits and by applying ordinary rounding techniques.

[0106] Notwithstanding that the numerical ranges and parameters setting forth the broad scope of the invention are approximations, the numerical values ​​set forth in the specific examples are reported as precisely as possible. Any numerical value, however, inherently contains certain errors necessarily resulting from the standard deviation found in their respective testing measurements.

[0107] Furthermore, it should be understood that any numerical range recited herein is intended to include all subranges subsumed therein. For example, a range of "1 to 10" is intended to include all subranges between (and including) the recited minimum value of 1 and the recited maximum value of 10, that is, having a minimum value equal to or greater than 1 and a maximum value equal to or less than 10.

[0108] As used herein, "comprising," "containing," and similar terms are understood in the context of this application to be synonymous with "including" and are therefore open-ended and do not exclude the presence of otherwise undescribed or unrecited 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 undescribed elements, ingredients, or method steps. As used herein, "consisting essentially of" is understood in the context of this application to include the specified elements, materials, ingredients, or method steps "as well as elements, materials, ingredients, or method steps that do not materially affect the basic and novel characteristics of the described content.

[0109] In this application, unless otherwise expressly stated, the use of the singular includes the plural and the plural encompasses the singular. For example, although "a" film-forming polymer containing an ionic salt group, "a" blocked polyisocyanate curing agent, and / or "a" bismuth catalyst are mentioned herein, a combination (i.e., multiple) of these components may be used. In addition, in this application, unless otherwise specifically stated, the use of "or" means "and / or", even though "and / or" may be explicitly used in some cases.

[0110] Although specific aspects of the present invention have been described in detail, it will be appreciated by those skilled in the art that various modifications and alternatives to the details may be developed based on the overall teachings of the present disclosure. Therefore, the specific arrangements disclosed are intended to be illustrative only and not to limit the scope of the present invention, which is given by the full scope of the appended claims and any and all equivalents thereof.

[0111] The following examples illustrate the invention, which, however, should not be considered to limit the invention to its details. Unless otherwise indicated, all parts and percentages in the following examples and throughout the specification are by weight.

[0112] Examples

[0113] Example 1: Blocked polyisocyanate curing agent comprising isocyanate groups blocked with a 1,2-polyol blocking agent Preparation of (crosslinking agents I and Ia-g)

[0114] The blocked polyisocyanate curing agent (crosslinking agents I and Ia to Ig) containing isocyanate groups blocked with 1,2-polyols was prepared in the following manner: Components 2 to 7 listed in Table 1 below were mixed in a flask set for total reflux while stirring under nitrogen. The mixture was heated to a temperature of 30°C, and component 1 was added dropwise so that the temperature increased and remained below 100°C due to the exothermic reaction. After the addition of component 1 was completed, a temperature of 100°C was established in the reaction mixture, and the reaction mixture was maintained at this temperature until no residual isocyanate was detected by IR spectroscopy. Components 8 to 9 were then added, and the reaction mixture was allowed to stir at 100°C for 30 minutes and then cooled to ambient temperature.

[0115] Table 1

[0116]

[0117] 1 Rubinate M, available from Huntsman Corporation.

[0118] Example 2: Preparation of comparative blocked polyisocyanate curing agents (crosslinking agents II and IIa-b)

[0119] A comparative blocked polyisocyanate curing agent (crosslinker IIa-b) not including a blocking group blocked with a 1,2-polyol was prepared in the following manner: Components 2 to 6 listed in Table 2 below were mixed in a flask set for total reflux while stirring under nitrogen. The mixture was heated to a temperature of 30°C, and component 1 was added dropwise so that the temperature increased and remained below 100°C due to the exothermic reaction. After the addition of component 1 was completed, a temperature of 100°C was established in the reaction mixture, and the reaction mixture was maintained at this temperature until no residual isocyanate was detected by IR spectroscopy. Components 7 to 8 were then added, and the reaction mixture was allowed to stir for 30 minutes and then cooled to ambient temperature.

[0120] Table 2

[0121]

[0122]

[0123] 1 Rubinate M, available from Huntsman Corporation.

[0124] Example 3: Cationic, amine-functionalized, polyepoxide-based resins containing crosslinkers Ia-g (resin dispersions Ia- g) Preparation

[0125] Cationic, amine functionalized, polyepoxide-based polymeric resins were prepared in the following manner. Components 1 to 5 listed in Table 3 below were mixed in a flask set for total reflux while stirring under nitrogen. The mixture was heated to a temperature of 130° C. and allowed to exotherm (maximum 175° C.). A temperature of 145° C. was established in the reaction mixture and the reaction mixture was then maintained for 2 hours. Component 6 was slowly introduced while the mixture was cooled to 125° C., followed by the addition of component 7. A temperature of 105° C. was established, and components 8 and 9 were then quickly added to the reaction mixture (sequential additions) and the reaction mixture was allowed to exotherm. A temperature of 120° C. was established and the reaction mixture was maintained for 1 hour to obtain resin synthesis products Ia-g.

[0126] Table 3

[0127]

[0128]

[0129] 1 EPON 828 is available from Hexion Corporation.

[0130] 2See Example 1 above. Resin Ia uses crosslinker Ia, Resin Ib uses crosslinker Ib, Resin Ic uses crosslinker Ic, Resin Id uses crosslinker Id, Resin Ie uses crosslinker Ie, Resin If uses crosslinker If, and Resin Ig uses crosslinker Ig.

[0131] 3 72.7 wt% (in MIBK) of the diketimine reaction product of 1 equivalent of diethylenetriamine and 2 equivalents of MIBK.

[0132] A portion of the resin synthesis product Ia-g (component 10) was then poured into the premixed solution of components 11 to 13 to form a resin dispersion, and the resin dispersion was stirred for 1 hour. Component 14 was then introduced over 30 minutes to further dilute the resin dispersion, followed by the addition of component 15. Free MIBK in the resin dispersion was removed from the dispersion under vacuum at a temperature of 60 to 70°C.

[0133] The solids content of the resulting cationic, amine-functionalized, polyepoxide-based polymeric resin dispersions (Resin Dispersions Ia-g of the present invention) containing a 1,2-polyol-based crosslinker added during the resin synthesis stage was determined by adding a certain amount of the resin dispersion to a tared aluminum pan, recording the initial weight of the resin dispersion, heating the resin dispersion in the pan in an oven at 110° C. for 60 minutes, allowing the pan to cool to ambient temperature, and reweighing the pan to determine the amount of remaining non-volatile content, and calculating the solids content by dividing the weight of the remaining non-volatile content by the initial resin dispersion weight and multiplying by 100. (Note that this procedure was used to determine the solids content of each of the resin dispersion examples described below). The solids contents of Resin Dispersions Ia-g are reported in Table 3.

[0134] Example 4: Preparation of Comparative Cationic, Amine-Functionalized, Polyepoxide-Based Resins (Comparative Resin Dispersions IIa-b)

[0135] Cationic, amine functionalized, polyepoxide-based polymeric resins were prepared in the following manner: Components 1 to 5 listed in Table 4 below were mixed in a flask set for total reflux while stirring under nitrogen. The mixture was heated to a temperature of 130° C. and allowed to exotherm (maximum 175° C.). A temperature of 145° C. was established in the reaction mixture and the reaction mixture was then maintained for 2 hours. Component 6 was slowly introduced while the mixture was cooled to 125° C., followed by the addition of components 7 and 8. A temperature of 105° C. was established, and then components 9 and 10 were quickly added to the reaction mixture (sequential additions) and the reaction mixture was allowed to exotherm. A temperature of 120° C. was established and the reaction mixture was maintained for 1 hour to obtain comparative resin synthesis products IIa-b.

[0136] Table 4

[0137]

[0138] 1 EPON 828 is available from Hexion Corporation.

[0139] 2 See Example 2 above. Resin Ha used crosslinker Ha, and Resin Ha used crosslinker Ha, and Resin Ha used crosslinker Ha.

[0140] 3 72.7 wt% (in MIBK) of the diketimine reaction product of 1 equivalent of diethylenetriamine and 2 equivalents of MIBK.

[0141] A portion of the comparative resin synthesis product IIa-b (component 11) was then poured into the premixed solution of components 12 to 14 to form a resin dispersion, and the resin dispersion was stirred for 1 hour. Component 15 was then introduced over 30 minutes to further dilute the resin dispersion, followed by the addition of component 16. Free MIBK in the resin dispersion was removed from the dispersion under vacuum at a temperature of 60 to 70° C. The solids content of the resin dispersion IIa-b is reported in Table 4.

[0142] Example 5: Preparation of cationic resins containing Jeffamine D2000 (cationic resins Va-Vb)

[0143] Table 5

[0144]

[0145]

[0146] 1 Polypropylene oxide resin terminated with primary amine, available from Huntsman Chemical

[0147] 2 Surfactants available from Solvay

[0148] Cationic resins were prepared from the materials included in Table 5 in the following manner: Materials 1, 2, and 3 were added to a suitably equipped round-bottom flask. The mixture was then heated to 125°C. Material 4 was then added. The reaction mixture was allowed to exotherm, after which the mixture was heated to 160°C. The reaction mixture was then kept at 160 to 170°C for 1 hour. Material 5 was then added and mixed thoroughly. Material 6 was then added, and the mixture was allowed to exotherm. Material 7 was then added and mixed thoroughly. The resulting reaction mixture was heated to 130°C and kept for 3 hours. Material 8 was then added, followed by material 9, and the mixture was stirred for 10 minutes. Materials 10 to 12 were premixed in a container, and the reaction mixture was added to an acidic aqueous solution under stirring to form a cationic dispersion. The dispersion was stirred for 30 minutes, and material 13 was then added.

[0149] Example 6: Preparation of cationic resin intermediates (Intermediates VIa-VIb)

[0150] Table 6

[0151]

[0152] 1 6 mole ethoxylate of bisphenol A.

[0153] 2 Tetronic 150R1 is a nonionic surfactant available from BASF.

[0154] 3 The diketimine is the reaction product of diethylenetriamine and methyl isobutyl ketone at 72.3% solids in methyl isobutyl ketone.

[0155] The cationic resin intermediate was prepared from the materials included in Table 6 in the following manner: Materials 1 to 6 were charged into a reaction vessel and heated to 125°C under a nitrogen atmosphere. Material 7 was added and the reaction was exothermed to about 180°C. When the reaction reached 160°C, it was held for 1 hour. After the peak exotherm, the resin was cooled back to 160°C and continued to be held. After holding, the reaction was then cooled to 130°C and material 8 was added. The reaction was held at 130°C until the extrapolated epoxy equivalent was 1,070, as measured using a Metrohm 799MPT Titrino automatic titrator using a 1M perchloric acid acetic acid solution. At the expected epoxy equivalent, materials 9 to 10 were added in sequence and the mixture was exothermed to about 150°C. At the peak exotherm, it was held for 1 hour while the reaction was cooled to 125°C. After holding for 1 hour, the resin was dispersed in an aqueous medium consisting of materials 11 to 13. The dispersion was subsequently reduced continuously with materials 14 to 16. The solvent was removed from the resulting cationic resin intermediate by vacuum distillation until the methyl isobutyl ketone content was less than 0.05% as measured by gas chromatography.

[0156] Example 7: Preparation of Cationic Resins Containing Intermediates VIa-VIb (Cationic Resins VIIa-VIIb)

[0157] Table 7

[0158]

[0159] 1 Cationic resin VIIa uses intermediate VIa, and cationic resin VIIb uses intermediate VIb.

[0160] 285% EPON 828 (epoxy resin available from Hexion Chemicals) + 15% solvent. For cationic resin Vila, the solvent was propylene glycol methyl ether, and for cationic resin Vilb, the solvent was methyl isobutyl ketone.

[0161] 3 Surfactants available from Solvay.

[0162] Cationic resins were prepared from the materials included in Table 7 in the following manner. Materials 1 to 3 were charged to a reactor and heated to 70°C. Material 4 was added over 15 minutes and mixed thoroughly. Materials 5 to 6 were added and the mixture was maintained at 70°C for 45 minutes. The mixture was then heated to 88 to 90°C and maintained at that temperature for 3 hours. Maintained for 2.5 hours, materials 7 to 8 were added. At the end of the hold, heat was removed and material 9 was added. The mixture was then cooled. Once the temperature reached 32°C, material 10 was added and the mixture was maintained for 1 hour while continuing to cool to obtain cationic resins VIIa-b.

[0163] Example 8: Preparation of Grinding Carrier 1

[0164] Table 8

[0165] # Material Serving size (g) 1 <![CDATA[EPON 828 1 ]]> 533.2 2 Nonylphenol 19.1 3 Bisphenol A 198.3 4 Ethyltriphenylphosphonium iodide 0.7 5 Butoxypropanol 99.3 Subtotal 850.6 6 Butoxypropanol 93.9 7 Methoxypropanol 50.3 Subtotal 994.8 8 Thiodiethanol 121.3 9 Butoxypropanol 6.9 10 Deionized water 32.1 11 Dimethylolpropionic acid 133.1 Subtotal 1288.2 12 Deionized water 1100 13 Deionized water 790

[0166] 1 The diglycidyl ether of bisphenol A is commercially available as Epon 828 from Resolution Chemical Company.

[0167] Grinding carrier 1 was prepared using the materials listed in Table 8 according to the following procedure: Materials 1 to 5 were charged into a suitably equipped flask and heated to 125°C. The mixture was allowed to exotherm to 175°C and then held at 160 to 165°C for 1 hour. After holding for 1 hour, materials 6 to 7 were added. The mixture was then cooled to 80°C and materials 8 to 11 were added. The mixture was held at 78°C until the measured acid value was less than 2, as measured using a Metrohm 799MPT Titrino automatic titrator using a 0.1M potassium hydroxide methanol solution. 1288.2 g of the resin was then poured into 1100 g of deionized water (material 12) by stirring. The mixture was mixed for 30 minutes, and then material 13 was added and mixed thoroughly.

[0168] Example 9: Preparation of Grinding Carrier 2

[0169] This example describes the preparation of a quaternary ammonium salt-containing pigment grind resin, Grind Vehicle 2. Grind Vehicle 2-1 describes the preparation of an amine-acid salt quaternizing agent and Grind Vehicle 2-2 describes the preparation of an epoxy group-containing polymer that is subsequently quaternized with the amine-acid salt of Grind Vehicle 2-1 to form Grind Vehicle 2.

[0170] Grinding carrier 2-1 : Prepare the amine-acid salt quaternizing agent using the materials listed in Table 9-1 according to the following procedure:

[0171] Table 9-1

[0172]

[0173]

[0174] 1 Polymeric diisocyanates, commercially available from Dow Chemical Co.

[0175] 2 Purchased from BASF Group as Mazon 1651.

[0176] A suitably equipped 5 liter flask was charged with material 1. Material 2 was then charged over a period of 1.5 hours under gentle stirring, followed by a rinse of material 3. During this addition, the reaction mixture was allowed to exotherm to a temperature of about 89°C and maintained at that temperature for about 1 hour until the isocyanate was completely reacted as determined by infrared spectroscopy. At this point, material 4 was added over a period of 25 minutes, followed by material 5. The reaction temperature was maintained at about 80°C for about 6 hours until a stable acid number of 70.6 was obtained, as measured using a Metrohm 799MPT Titrino automatic titrator using 0.1M potassium hydroxide in methanol.

[0177] Grinding carrier 2-2 : Prepare the polymer containing quaternary ammonium salt groups using the materials listed in Table 9-2 according to the following procedure:

[0178] Table 9-2

[0179] # Material Serving size (g) 1 <![CDATA[Diglycidyl Ether of Bisphenol A 1 > 528.8 2 Bisphenol A 224.9 3 <![CDATA[Butyl carbitol formal 2 > 83.7 4 Ethyltriphenylphosphonium iodide 0.5 5 <![CDATA[Butyl carbitol formal 2 > 164.9 6 Amine-acid salt quaternizing agent 2-1 418.4 7 Deionized water 1428.1 8 <![CDATA[Butyl carbitol formal 2 > 334.7

[0180] 1 Diglycidyl ether of bisphenol A is commercially available as EPON 828 from Resolution Chemical Company.

[0181] 2 Purchased from BASF Group as Mazon 1651.

[0182] Material 1 is charged into a suitably equipped 5-liter flask under gentle stirring. Material 2 is then added, followed by material 3 and material 4. The reaction mixture is heated to about 140°C, allowed to exotherm to about 180°C, then cooled to about 160°C and maintained at this temperature for about 1 hour. At this point, the polymer product has an epoxy equivalent of 982.9, as measured using a Metrohm 799MPT Titrino automatic titrator using a 1M perchloric acid acetic acid solution. The reaction mixture is then cooled to a temperature of about 130°C, at which time material 5 is added and the temperature is reduced to about 95°C to 100°C, followed by the addition of material 6, 2-1 amine-acid quaternizing agent within 15 minutes, and subsequent addition of about 1428.1 parts by weight of deionized water. The reaction temperature is maintained at about 80°C for about 6 hours until the acid value of the reaction product drops below 1.0, as measured using a Metrohm 799MPT Titrino automatic titrator using a 0.1M potassium hydroxide methanol solution. The resulting pigment grind resin containing quaternary ammonium salt groups was further reduced with about 334.7 parts by weight of butyl carbitol formal solvent to reduce the solids content.

[0183] Example 10: Preparation of pigment paste 1:

[0184] The pigment dispersion was prepared by sequentially adding the ingredients listed below under high shear mixing. When the ingredients were thoroughly blended, the pigment dispersion was transferred to a vertical sand mill and ground to a Hegman value of >7.5 as measured using a Hegman gauge.

[0185] Table 10

[0186] # Material Weight 1 Grinding carrier 1 734.02 2 n-Butoxypropanol 28.23 3 <![CDATA[Silica pigment 1 > 96.95 4 Deionized water 57.57

[0187] 1 Gasil IJ35 supplied by INEOS

[0188] Example 11: Preparation of Pigment Paste 2 :

[0189] The pigment dispersion was prepared by sequentially adding the ingredients listed below under high shear mixing. When the ingredients were thoroughly blended, the pigment dispersion was transferred to a vertical sand mill and ground to a Hegman value > 7.5.

[0190] Table 11

[0191] # Material Weight 1 Grinding carrier 1 308.76 2 Grinding carrier 2 121.90 3 Dioctyltin oxide 324.04 4 Deionized water 168.52 5 Butyl Carbitol Formal 11.23

[0192] Example 12: Preparation of Pigment Paste 3 :

[0193] A catalyst-free pigment dispersion was prepared by sequentially adding ingredients 1 to 7 listed below under high shear mixing. When the ingredients were thoroughly blended, the pigment dispersion was transferred to a vertical sand mill and ground to a Hegman value > 7.5. Feed 8 was then mixed into the paste using a Cowles blade for 1 hour.

[0194] Table 12

[0195]

[0196]

[0197] 1 Carbon black pigment supplied by Orion Engineered Carbon

[0198] 2 Kaolin clay purchased from BASF

[0199] 3 Pigment grades from The Chemours Company

[0200] Example 13: Preparation of Bismuth Catalyst Solution

[0201] An aqueous bismuth methanesulfonate catalyst solution was prepared using the ingredients from Table 13 in the following manner: Component 1 was added to a conical flask with stirring, followed by sequential introduction of components 2 and 3. The contents of the flask were stirred at room temperature for 3 hours, and the resulting catalyst solution was then filtered through a Buchner funnel to remove any undissolved residues.

[0202] Table 13

[0203] # Material Serving size (g) 1 Deionized water 3645.05 2 <![CDATA[Methanesulfonic acid 1 > 220.07 3 <![CDATA[Bismuth(III) oxide 2 > 172.16

[0204] 1 70% deionized water solution.

[0205] 2 5N Frit Grade.

[0206] Example 14: Preparation of Comparative Electrodepositable Coating Compositions A and B

[0207] Table 14

[0208]

[0209] For each coating composition, Feeds 1 to 5 were added sequentially to a plastic container at room temperature with stirring, stirring for 10 minutes after each addition. The mixture was stirred at room temperature for at least 30 minutes. Feeds 6 and 7 were then added, and the coating was stirred until uniform, for a minimum of 30 minutes. Feed 8 was added, and the coating was stirred for a minimum of 30 minutes until uniform. The solids content of the resulting cationic electrodepositable coating composition was 20.5%, and the weight ratio of pigment to binder was 0.12 / 1.0, as determined previously.

[0210] Coated panels were prepared from baths containing the respective cationic electrodepositable coating compositions after 20% ultrafiltration (and reconstitution with deionized water) and evaluated for solvent resistance by diacetone rubbing. The results are reported below.

[0211] Example 15: Preparation of Experimental Electrodepositable Coating Composition C and Comparative Electrodepositable Coating Composition D

[0212] Table 15

[0213]

[0214] For each coating composition, Feeds 1 to 5 were added sequentially to a plastic container at room temperature with stirring, stirring for 10 minutes after each addition. The mixture was stirred at room temperature for at least 30 minutes. Feed 6 was then added and the coating was stirred until homogeneous for a minimum of 30 minutes. Feed 7 was added and the coating was stirred for a minimum of 30 minutes until homogeneous. The resulting cationic electrodepositable coating composition had a solids content of 20.5%, with a pigment to binder weight ratio of 0.12 / 1.0, as determined previously.

[0215] Coated panels were prepared from baths containing the respective cationic electrodepositable coating compositions after 20% ultrafiltration (and reconstitution with deionized water) and evaluated for solvent resistance by diacetone rubbing. The results are reported below.

[0216] Example 16: Preparation of Electrodepositable Coating Composition EJ

[0217] Table 16

[0218]

[0219]

[0220] For each coating composition, Feeds 1 to 5 were added sequentially to a plastic container at room temperature with stirring, stirring for 10 minutes after each addition. The mixture was stirred at room temperature for at least 30 minutes. Feeds 6 and 7 were then added and the coating was stirred until homogeneous for a minimum of 30 minutes. Feed 8 was added and the coating was stirred for a minimum of 30 minutes until homogeneous. The solids content of the resulting cationic electrodepositable coating composition was 20.5%, and the weight ratio of pigment to binder was 0.12 / 1.0, as determined previously.

[0221] Coated panels were prepared from baths containing the respective cationic electrodepositable coating compositions and evaluated for solvent resistance by diacetone rubbing. The results are reported below.

[0222] Example 17: Preparation of Electrodepositable Coating Composition KM

[0223] Table 17

[0224]

[0225] For each coating composition, Feeds 1 to 5 were added sequentially to a plastic container at room temperature with stirring, stirring for 10 minutes after each addition. The mixture was stirred at room temperature for at least 30 minutes. Feeds 6 to 8 were then added and the coating was stirred until homogeneous for a minimum of 30 minutes. Feed 9 was added and the coating was stirred for a minimum of 30 minutes until homogeneous. The resulting cationic electrodepositable coating composition had a solids content of 20.5%, determined as previously described, and a pigment to binder weight ratio of 0.12 / 1.0.

[0226] Coated panels were prepared from baths containing the respective cationic electrodepositable coating compositions and evaluated for solvent resistance by diacetone rubbing. The results are reported below.

[0227] Example 18: Preparation of Electrodepositable Coating Composition NQ

[0228] Table 18

[0229]

[0230] For each coating composition, Feeds 1 to 5 were added sequentially to a plastic container at room temperature with stirring, stirring for 10 minutes after each addition. The mixture was stirred at room temperature for at least 30 minutes. Feeds 6 and 7 were then added and the coating was stirred until homogeneous for a minimum of 30 minutes. Feed 8 was added and the coating was stirred for a minimum of 30 minutes until homogeneous. The solids content of the resulting cationic electrodepositable coating composition was 20.5%, and the weight ratio of pigment to binder was 0.12 / 1.0, as determined previously.

[0231] Coated panels were prepared from baths containing the respective cationic electrodepositable coating compositions and evaluated for solvent resistance by diacetone rubbing. The results are reported below.

[0232] Evaluation of Cationic Electrodepositable Coating Compositions

[0233] The composition of each of the above coatings was coated onto 4"X 6"X.032" C700 chemical free immersion deionized water rinsed steel panels (provided by ACT Test Panels LLC) for cure by solvent rub testing. The coating conditions for both substrates were 190 volts for 3 minutes at a bath temperature of 30 to 34°C. The coated substrates were rinsed with deionized water and air dried for a period of at least 30 minutes.

[0234] Curing evaluation of electrodeposited coatings

[0235] The electrodepositable coatings applied by the above method onto 4"X 6"X.032" C700 No Chemseal dipped deionized water rinsed steel panels were baked at 140°C, 150°C, 155°C and 175°C using an electric oven (Despatch Industries, LFD series model) with a fixed baking time of 25 minutes. The dry film thickness of each of the panels was 0.7 to 0.9 mil (17 to 23 microns). The baked electrodeposited coatings were double rubbed with a cotton glove provided by Uline, which was placed on top of a nitrile glove soaked with excess acetone for testing. The rubs were calculated as double rubs (one rub forward and one rub backward constitutes a double rub). The cure temperature (TCURE) is determined for the baking temperature that results in the electrodeposited coating having no physical damage to the metal of the coating after 100 double rubs with acetone. This test method is referred to herein as the double rub test (DBA) method.

[0236] The electrodepositable coating was coated on a 200-gauge aluminum foil by the above method, and non-isothermal thermogravimetric analysis ("TGA") was performed using a thermogravimetric analyzer (TGAQ500, TA Instruments, Inc.). TGA data were collected at a heating rate of 5°C / min in the temperature range of 20°C to 250°C. It is generally understood that the deblocking reaction of the blocked isocyanate in the crosslinking agent has a direct effect on the crosslinking reaction of the blocked isocyanate and the polymer system containing hydroxyl or amine groups. The theory behind thermogravimetric analysis is weight loss, which is the result of the weight loss of the coating caused by the deblocking of the blocking agent from the isocyanate groups on the polyisocyanate and volatilization of the coating. TGA data measures the deblocking reaction curve over the temperature range from the 1st derivative weight loss curve to determine the crosslinking reaction temperature. This test method is referred to as the TGA test method in this article. The results are summarized as follows: 固化TGA .

[0237] Table 19

[0238]

[0239] The results in the above table show the unexpected result that the combination of a bismuth catalyst and a blocked polyisocyanate having blocking groups comprising propylene glycol has the lowest cure temperature of all the coatings tested.

[0240] Table 20

[0241] Examples %1,2-diol capping agent 175℃ 155℃ 150℃ 140℃ <![CDATA[T 固化DBA ]]> <![CDATA[T 固化TGA ]]> E 100％ 100 100 100 100 140 141.85 F 80％ 100 100 100 100 140 154.23 G 60％ 100 100 100 100 140 151.1 H 40％ 100 100 100 100 140 167.43 Compound I 20％ 100 100 100 52 150 169.07 Compound J 0％ 100 100 64 9 155 171.75

[0242] The above results show that a sufficient amount of propylene glycol is required to achieve a lower temperature cure compared to non-diol end-capping groups with bismuth catalysts.

[0243] Table 21

[0244]

[0245] The above results show that when the content of propylene glycol in the crosslinking agent is insufficient, a lower curing temperature cannot be achieved even if the catalyst content is high.

[0246] Table 22

[0247] Examples Capping agent 175℃ 155℃ 150℃ 140℃ <![CDATA[T 固化DBA ]]> <![CDATA[T 固化TGA ]]> E 1,2-Propanediol 100 100 100 100 140 141.85 N 1,2-Butanediol 100 100 100 100 140 153.9 O 1,2-Hexanediol 100 100 100 100 140 148.97 Compound P 1,3-Butanediol 100 100 82 36 155 160.13 Compound J Diethylene glycol monobutyl ether 100 100 64 9 155 172.84

[0248] The above results show that the 1,2-diol structure is essential for the lower curing temperature using bismuth catalysts.

[0249] Table 23

[0250] Examples catalyst 175℃ 155℃ 150℃ 140℃ <![CDATA[T 固化DBA ]]> <![CDATA[T 固化TGA ]]> E bismuth 100 100 100 100 140 141.85 Compound M tin 100 100 100 29 150 169.44

[0251] The above results show the catalyst specificity of bismuth for curing temperature compared to tin.

[0252] Those skilled in the art will appreciate that, based on the above disclosure, many modifications and variations are possible without departing from the broad inventive concepts described and exemplified herein. Therefore, it should be understood that the above disclosure is merely an illustration of various exemplary aspects of the present application, and within the spirit and scope of the present application and the appended claims, those skilled in the art can easily make many modifications and variations.

Claims

1. An electrodepositable coating composition comprising: a film-forming polymer containing ionic salt groups, the film-forming polymer comprising active hydrogen functional groups; A blocked polyisocyanate curing agent comprising blocking groups, wherein at least 30% of the blocking groups, based on the total number of blocking groups, comprise 1,2-alkanediol as a blocking agent; and A bismuth catalyst, wherein the bismuth catalyst comprises bismuth methanesulfonate present in an amount of at least 0.5 wt % bismuth metal based on total resin solids weight.

2. The electrodepositable coating composition according to claim 1, wherein the blocked polyisocyanate curing agent comprises the following structure: wherein R is hydrogen or a substituted or unsubstituted alkyl group containing 1 to 8 carbon atoms.

3. The electrodepositable coating composition of claim 1 or 2, wherein the 1,2-alkanediol comprises 30% to 95% of the blocked groups of the blocked polyisocyanate curing agent, based on the total number of blocked groups.

4. The electrodepositable coating composition of claim 1, wherein the 1,2-alkanediol comprises ethylene glycol, propylene glycol, 1,2-butanediol, 1,2-pentanediol, 1,2-hexanediol, 1,2-heptanediol, 1,2-octanediol, or a combination thereof.

5. The electrodepositable coating composition of claim 1 or 2, wherein the 1,2-alkanediol comprises propylene glycol.

6. The electrodepositable coating composition according to claim 1 or 2, wherein the blocked polyisocyanate curing agent further comprises a co-blocking agent.

7. The electrodepositable coating composition of claim 6, wherein the co-capping agent comprises an aliphatic monoalcohol, an alicyclic monoalcohol, an aromatic alkyl monoalcohol, a phenolic compound, a glycol ether, a glycol amine, an oxime, a 1,3-alkanediol, a caprolactam, a dialkylamine, or a combination thereof.

8. The electrodepositable coating composition of claim 7, wherein the co-capping agent comprises benzyl alcohol or allyl alcohol.

9. The electrodepositable coating composition of claim 6, wherein the co-capping agent comprises methanol, ethanol, n-butanol, cyclohexanol, methyl phenyl carbinol, phenol, cresol, nitrophenol, ethylene glycol monobutyl ether, diethylene glycol butyl ether, ethylene glycol monomethyl ether, propylene glycol monomethyl ether, methyl ethyl ketone oxime, acetone oxime, cyclohexanone oxime, 1,3-butanediol, benzyl alcohol, allyl alcohol, dibutylamine, or a combination thereof.

10. The electrodepositable coating composition of claim 6, wherein the co-blocking agent comprises up to 70% of the blocking groups of the blocked polyisocyanate curing agent, based on the total number of blocking groups.

11. The electrodepositable coating composition of claim 1 or 2, wherein the bismuth catalyst further comprises bismuth oxide, a bismuth salt other than bismuth methanesulfonate, or a combination thereof.

12. The electrodepositable coating composition of claim 1 or 2, wherein the bismuth catalyst further comprises bismuth carboxylate, bismuth sulfamate, bismuth sulfonate other than bismuth methanesulfonate, bismuth lactate, bismuth subnitrate, or a combination thereof.

13. The electrodepositable coating composition according to claim 1 or 2, wherein the film-forming polymer containing an ionic salt group comprises a film-forming polymer containing a cationic salt group.

14. The electrodepositable coating composition according to claim 1 or 2, wherein the film-forming polymer containing an ionic salt group comprises a film-forming polymer containing an anionic salt group.

15. The electrodepositable coating composition of claim 1 or 2, wherein the film-forming polymer containing ionic salt groups comprises active hydrogen functional groups.

16. The electrodepositable coating composition of claim 1 or 2, wherein the blocked polyisocyanate curing agent is present in the electrodepositable coating composition in an amount of 10 to 60 weight percent, based on the total weight of resin solids of the electrodepositable coating composition.

17. The electrodepositable coating composition of claim 1 or 2, wherein the film-forming polymer containing ionic salt groups is present in the electrodepositable coating composition in an amount of 40% to 90% by weight, based on the total weight of the resin solids of the electrodepositable coating composition.

18. The electrodepositable coating composition of claim 1 or 2, wherein the electrodepositable coating composition further comprises a co-catalyst.

19. The electrodepositable coating composition of claim 18, wherein the co-catalyst is present in an amount less than 0.01 wt. % based on the total resin solids weight of the composition.

20. The electrodepositable coating composition of claim 18, wherein the co-catalyst is present in an amount less than 0.001 wt. % based on the total resin solids weight of the composition.

21. An electrodepositable coating composition according to claim 1 or 2, wherein a co-catalyst is not present in the composition.

22. The electrodepositable coating composition of claim 1 or 2, wherein tin is present in an amount less than 0.01 wt. %, based on the total resin solids weight of the composition.

23. The electrodepositable coating composition of claim 1 or 2, wherein tin is present in an amount less than 0.001 wt. %, based on the total resin solids weight of the composition.

24. An electrodepositable coating composition according to claim 1 or 2, wherein tin is absent from the composition.

25. An electrodepositable coating composition according to claim 1 or 2, wherein the bismuth subnitrate, bismuth oxide, bismuth silicate, bismuth titanate, bismuth sulfamate and / or bismuth lactate is present in an amount of less than 0.01 wt % based on the total resin solids weight of the composition.

26. An electrodepositable coating composition according to claim 1 or 2, wherein the bismuth subnitrate, bismuth oxide, bismuth silicate, bismuth titanate, bismuth sulfamate and / or bismuth lactate is present in an amount of less than 0.001 wt %, based on the total resin solids weight of the composition.

27. An electrodepositable coating composition according to claim 1 or 2, wherein bismuth subnitrate, bismuth oxide, bismuth silicate, bismuth titanate, bismuth sulfamate and / or bismuth lactate are not present in the composition.

28. The electrodepositable coating composition of claim 1 or 2, wherein the bismuth catalyst is provided in an amount of at least 1 wt% bismuth metal based on the total resin solids weight of the composition.

29. The electrodepositable coating composition of claim 1 or 2, wherein the bismuth catalyst is provided in an amount of at least 0.5 wt% bismuth metal, based on the total resin solids weight of the composition, and the 1,2-alkanediol comprises 100% of the capping groups of the blocked polyisocyanate curing agent, based on the total number of capping groups.

30. The electrodepositable coating composition of claim 1 or 2, wherein the bismuth catalyst is provided in an amount of at least 0.5 wt% bismuth metal, based on the total resin solids weight of the composition, and the 1,2-alkanediol comprises a percentage of the capping groups of the blocked polyisocyanate curing agent greater than or equal to [(-1.2x + 1.6)*100]% or 30%, whichever is greater, wherein x is the weight percentage of bismuth metal, and the percentage of capping groups is based on the total number of capping groups.

31. The electrodepositable coating composition of claim 1 or 2, wherein the end-capping group is free of an end-capping agent comprising a polyester diol formed by the reaction of ethylene glycol, propylene glycol or 1,4-butanediol with oxalic acid, succinic acid, adipic acid, suberic acid or sebacic acid.

32. The electrodepositable coating composition of claim 1 or 2, wherein the electrodepositable coating composition further comprises a plasticizer.

33. The electrodepositable coating composition of claim 32, wherein the plasticizer comprises a polyalkylene glycol.

34. The electrodepositable coating composition of claim 33, wherein the polyalkylene glycol comprises at least two secondary hydroxyl functional groups.

35. An electrodepositable coating composition according to claim 33 or 34, wherein the polyalkylene glycol comprises polypropylene glycol.

36. The electrodepositable coating composition of claim 1 or 2, wherein the electrodepositable coating composition comprises solubilized bismuth metal in an amount of at least 0.04 wt. %, based on the total weight of the electrodepositable coating composition.

37. The electrodepositable coating composition of claim 1 or 2, wherein the electrodepositable coating composition comprises solubilized bismuth metal in an amount of at least 0.22 wt. %, based on the total resin solids weight of the electrodepositable coating composition.

38. A method of coating a substrate comprising electrophoretically applying a coating deposited from the electrodepositable coating composition of any preceding claim 1 to 37 to at least a portion of the substrate.

39. The method of claim 38, wherein the method further comprises heating the coated substrate to effect curing of the coating.

40. The method of claim 39, wherein the coating has a T of no more than 140°C as measured by the double rub test method. 固化 .

41. The method of claim 39 or 40, wherein the coating has a T of less than 170°C as measured by the TGA test method. 固化 .

42. A coating which is an at least partially cured coating formed by at least partially curing a coating deposited from the electrodepositable coating composition of any preceding claim 1 to 37.

43. A substrate coated with a coating deposited from an electrodepositable coating composition as claimed in any one of the preceding claims 1 to 37 in an at least partially cured state.

44. The substrate of claim 43, wherein the substrate comprises a three-dimensional component formed by an additive manufacturing process.

45. The substrate of claim 44, wherein the additive manufacturing process comprises one or more of: selective laser melting, electron beam melting, directed energy deposition, metal extrusion, or binder jetting.

Images