FIELD: chemistry.
SUBSTANCE: invention relates to a method of producing self-curing polyurethane dispersions, use thereof as coating agents, coating agents containing these self-curing aqueous dispersions, a method of coating substrates, as well as substrates treated with coating agents. The method of producing self-curing aqueous polyurethane dispersions involves the following steps: I. reacting al) polyisocyanate with a mixture of, a2) 2,2-bis(hydroxymethyl)alkanecarboxylic acid as an anionic hydrophilisation agent containing a group which is reactive towards isocyanate and, a3) at least one polyol component with average OH-functionality >1, wherein any mixture from a2) and a3), or component a1) k) contains at least one catalyst selected from a group consisting of tertiary amines, tin, zinc or bismuth compounds; II obtaining an OH-functional polyurethane without NCO-groups from step I, which then; III. a4) is mixed with a reactive blocking agent for isocyanate groups, selected from a group consisting of butanone oxime, diisopropylamine or tert-butylbenzylamine, 3,5-dimethylpyrazole, triazole, respectively, mixture thereof; IV. subsequent reaction of that mixture from step III with a5) one or more polyisocyanates selected from group a1), wherein these polyisocyanates are the same as or are different from al), and subsequent V. obtaining a physical mixture of OH-functional polyurethane without NCO-groups and a blocked polyisocyanate from step IV, after which after either; VI. acid groups of OH-functional polyurethane a6) are completely or partially deprotonated by adding a neutralising agent; VII. and the polyurethane obtained at step VI id dispersed in water, or step VII is carried out before step VI.
EFFECT: obtaining self-curing aqueous polyurethane dispersions containing negligible amounts of cosolvent.
14 cl, 1 tbl, 5 ex
