Polyisocyanate containing allophanate and blocked isocyanato groups derived from diphenylmethanediisocyanate

PROBLEM TO BE SOLVED: To provide an improved polyisocyanate cross-linking agent derived from diphenylmethanediisocyanate and blocked with diethyl malonate. SOLUTION: This agent is a polyisocyanate prepared from diphenylmethanediisocyanate and of which at least 95% of the isocyanato groups is blocked with diethyl malonate. On the basis of the solid content, nonblocked and blocked isosyanato group contents of 9-13% (calculated as NCO) and an allophanate group content of 3-9% (calculated as C 2 HN 2 O 3 ) are included, and the calculated value of average functionality is 2.0-2.5. COPYRIGHT: (C)1997,JPO