To obtain an urethodione-modified polyisocyanate suitable for producing a polyurethane resin, etc., by adding a specific catalyst to a mixed isocyanate consisting of specific different diisocyanates and performing a reaction.
This urethodione-modified polyisocyanate is obtained by adding 0.1-5wt.% dimerization catalyst to a mixed isocyanate consisting of 50-95wt.% polymeric-diphenylmethanediisocyanate(MDI) of the formula [(n)=0 or ≥1] and 50-5wt.% organic diisocyanate and reacting the mixture. A preferable polymer MDI consists of 20-70wt.% component having (n)=0 and 80-30wt.% component having n≥1 in the formula. As the organic diisocyanate, 4,4'- diphenylmethanate-diisocyanate, 2,4-trilenediisocyanate, hexamethylenediisocyante, etc., are cited. As the dimerization catalyst, e.g. a trialkylphospine and pyrridine are cited. The isocyanate group exists in the composition obtained in this method even at a high temperature.
TANI KENSUKE
KUNISHIGE NOBORU
Next Patent: HIGHLY CONCENTRATED LIQUID STATE SECONDARY ALCOHOL ETHOXYSULFATE SALT COMPOSITION