Patent ID: 11952505
Assignee: SWIMC LLC
Field: Macromolecular chemistry, polymers (Chemistry)
Classification: CPC C | IPC C

Claim 14:
15. A method of delaying the onset of crosslinking in a waterborne one-component coating composition capable of self-crosslinking at room temperature, the method comprising:
(a) applying a one-component coating composition to a substrate, the one-component coating composition including
a first, urethane phase including a polyurethane polymer with at least one of polyester diol monomer units, polycarbonate diol monomer units, and ketone-functionalized diol monomer units;
a second phase including polymer having monomer units selected from one of alkyl (meth)acrylate monomer units, vinyl acetate monomer units, styrene monomer units, ketone-functional vinyl monomer units, or combinations thereof, the second phase having a glass transition temperature of about 0° C. to about 100° C., wherein the urethane phase comprises about 1 to 10 weight percent of the ketone-functionalized diol monomer units based on the weight of the urethane phase;
a hydrazine-functionalized crosslinking agent configured to crosslink the ketone-functionalized diol monomer units or the ketone-functionalized diol monomer units and the ketone-functional vinyl monomer units; and
one or more reaction moderators, wherein the one or more reaction moderators are present in the coating composition at 1 to 4 weight percent based on the combined weight of the first and second phases; and
wherein the one or more reaction moderators are selected from the group consisting of dimethyl amino hydroxyl propane, dimethylamino-2-methyl-1-proponol, N—N-dimethyl-3-methoxypropylamine, dimethylaminoethanol and combinations thereof; and
(b) evaporating the one or more reaction moderators from the applied coating composition at about 20 to about 25° C. to lower the pH thereof below about 7 to initiate imine bond formation between the ketone-functionalized diol monomer units or the ketone-functionalized diol monomer units and the ketone-functional vinyl monomer units and the hydrazine-functionalized crosslinking agent.