# US 6,723,765 B2 · Autodeposited coating of epoxy and OH groups-containing resin with NCO lower T crosslinker and higher T crosslinker > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 6,723,765 B2 - Document ID: US6723765B2 - Status: Granted - Kind: B2 - Application number: 10/339,823 - Filed: 2003-01-10 - Published: 2003-07-31 - Granted: 2004-04-20 - Earliest claimed: 2001-08-31 - Assignees: Henkel Corporation - Inventors: Brian D. Bammel - Web page: https://patentgrep.com/patent/US6723765B2 ## CPC - C08G 18/8074: {Lactams} - C08G 18/581: {Reaction products of epoxy resins with less than equivalent amounts of compounds containing active hydrogen added before or during the reaction with the isocyanate component (with amines C08G18/584)} - C08G 18/798: {containing urethdione groups} - C09D 5/088: {Autophoretic paints} - Y10T 428/31511: Of epoxy ether - C08G: MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS - C09D: COATING COMPOSITIONS, e.g. PAINTS, VARNISHES OR LACQUERS; FILLING PASTES; CHEMICAL PAINT OR INK REMOVERS; INKS; CORRECTING FLUIDS; WOODSTAINS; PASTES OR SOLIDS FOR COLOURING OR PRINTING; USE OF MATERIALS THEREFOR (cosmetics A61K; processes for applying liquids or other fluent materials to surfaces, in general, B05D; staining wood B27K5/02; glazes or vitreous enamels C03C; natural resins, French polish, drying-oils, driers, turpentine, per se, C09F; polishing compositions other than French polish, ski waxes C09G; adhesives or use of materials as adhesives C09J; materials for sealing or packing joints or covers C09K3/10; materials for stopping leaks C09K3/12; processes for the electrolytic or electrophoretic production of coatings C25D) - Y10T: TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION ## Abstract Autodeposition compositions for polymeric coatings of reduced gloss are prepared using resins having at least one hydroxy group and at least one epoxy group per molecule, a low temperature crosslinker and a high temperature crosslinker. The low temperature crosslinker forms a reactive prepolymer that may be subsequently mixed or emulsified with a high temperature crosslinker to form an autodeposition composition. Alternatively, a hybrid crosslinking agent may be utilized which contains both free isocyanate groups reactive at a relatively low temperature with the resin and at least one functional group capable of reacting with the resin only at a relatively elevated temperature. When deposited and cured, the resulting coating has a matte finish that is resistant to surface defects. ## Claims ### Claim 1 A cured autodeposited coating comprising the reaction product of: (a) a resin containing one or more epoxy groups and one or more hydroxy groups per molecule; and (b) one or more crosslinking agents, wherein at least one crosslinking agent contains two or more free isocyanate groups per molecule capable of reacting with the hydroxy groups of the resin at a first temperature and at least one crosslinking agent contains one or more functional groups per molecule capable of reacting with said resin only at a second temperature which is greater than the first temperature. ### Claim 2 (depends on 1) The cured autodeposited coating of claim 1 wherein said resin is prepared by reacting a glycidyl ether of a polyhydric phenol, a flexibilizing epoxy resin, and a chain extender containing at least two epoxy-reactive groups per molecule selected from hydroxyl, carboxylic acid, carboxylic acid anhydride, or combinations thereof. ### Claim 3 (depends on 2) The cured autodeposited coating of claim 2 wherein the polyhydric phenol is bisphenol A. ### Claim 4 (depends on 2) The cured autodeposited coating of claim 2 wherein the flexibilizing epoxy resin is a glycidyl ether derived from cardanol. ### Claim 5 (depends on 2) The cured autodeposited coating of claim 2 wherein the chain extender is a polyhydric phenol. ### Claim 6 (depends on 1) The cured autodeposited coating of claim 1 wherein the resin conforms to the chemical structure: and “n” is an integer from 1 to 50. ### Claim 7 (depends on 1) The cured autodeposited coating of claim 1 wherein at least one of said functional groups capable of reacting with said resin only at a second temperature which is greater than the first temperature is a blocked isocyanate group. ### Claim 8 (depends on 1) The cured autodeposited coating of claim 1 wherein at least one crosslinking agent contains two or more blocked isocyanate groups per molecule. ### Claim 9 (depends on 1) The cured autodeposited coating of claim 1 wherein at least one crosslinking agent is selected from the group consisting of aliphatic and aromatic polylsocyanates. ### Claim 10 (depends on 1) The cured autodeposited coating of claim 1 wherein at least one crosslinking agent is selected from the group consisting of MDI, TDI, HMDI, isophorone disocyanate, cyclohexane diisocyanate and mixtures thereof. ### Claim 11 (depends on 1) The cured autodeposited coating of claim 1 wherein at least one of the functional groups capable of reacting with said resin only at a second temperature which is greater than the first temperature is selected from the group consisting of amine, amide, imine, thiol, hydroxyl, carboxyl, carboxylic acid anhydride and combinations thereof. ### Claim 12 (depends on 1) The cured autodeposited coating of claim 1 wherein at least one of said crosslinking agents has the structure: wherein R and R1 are independently selected from aliphatic, cycloaliphatic, alkylaromatic or aromatic radicals. ### Claim 13 (depends on 1) The cured autodeposition coating of claim 1 wherein at least one of said crosslinking agents has a uretdione structure. ### Claim 14 (depends on 1) The cured autodeposition coating of claim 1 wherein at least one of said crosslinking agents is prepared by dimerization or trimerization of a polyisocyanate. ### Claim 15 (depends on 1) The cured autodeposition coating of claim 1 wherein at least one of said crosslinking agents is an isocyanete-containing uretdione. ### Claim 16 (depends on 1) The cured autodeposited coating of claim 1 in combination with a metallic substrate. ### Claim 17 (depends on 1) The cured autodeposited coating of claim 1 having a thickness of from about 5 to 50 microns. ### Claim 18 An autodeposition composition comprising: a. water; b. a reactive prepolymer which comprises a reaction product of (i) a resin containing at least one epoxy group and at least one hydroxyl group reactive with a free isocyanate group at a first temperature, and (ii) a low temperature crosslinking agent containing free isocyanate groups reactive with said hydroxyl group at said first temperature; and c. a high temperature crosslinking agent capable of reacting with said reactive prepolymer only at a second temperature which is higher the first temperature. ### Claim 19 (depends on 18) The autodeposition composition of claim 18 wherein said resin is prepared by reacting an epoxy resin which is a diglycidyl ether of a polyhydric phenol, a flexibilizing epoxy resin, and a chain extender containing at least two epoxy reactive groups selected from hydroxy), carboxylic acid, carboxylic acid anhydride and combinations thereof. ### Claim 20 (depends on 19) The autodeposition composition of claim 19 wherein the epoxy resin is glycidyl ether of bisphenol A. ### Claim 21 (depends on 19) The autodeposition composition of claim 19 wherein the flexibilizing epoxy resin is a glycidyl ether derived from cardanol. ### Claim 22 (depends on 19) The autodeposition composition of claim 19 wherein the chain extender is a polyhydric phenol. ### Claim 23 (depends on 18) The autodeposition composition of claim 18 wherein the resin is an epoxy resin conforming to the general chemical structure: and “n” Is an Integer from 1 to 50. ### Claim 24 (depends on 19) The autodeposition composition of claim 19 additionally comprising at least one further component selected from the group consisting of emulsifying agents, accelerators, colorants, coalescing solvents, leveling agents, and combinations thereof. ### Claim 25 (depends on 18) The autodeposition composition of claim 18 wherein the low temperature crosslinking agent is selected from the group consisting of MDI, TDI, HMDI, isophorone dsisocyanate, cyclohexane dilsocyanate and mixtures thereof. ### Claim 26 (depends on 18) The autodeposition composition of claim 18 wherein the high temperature crosslinking agent contains one or more blocked isocyanate groups. ### Claim 27 (depends on 18) The autodeposition composition of claim 18 wherein said reactive prepolymer and said high temperature crosslinking agent are in emulsified or dispersed form. ### Claim 28 (depends on 18) A metallic substrate coated by the autodeposition composition of claim 18. ### Claim 29 (depends on 18) A method of forming a coating on a metallic substrate, said method comprising contacting the metallic substrate with the autodeposition composition of claim 18 for a time effective to form a layer comprised of the reactive prepolymer and the high temperature crosslinking agent on the metallic substrate and curing said layer to form said coating. ### Claim 30 (depends on 29) The method of claim 29 wherein said autodeposition composition is additionally comprised of an accelerator. ### Claim 31 (depends on 29) The method of claim 29 wherein said curing is performed at a temperature of between about 130° C. and 240° C.