Patent ID: 7030274

Claim:
A process for the preparation of liquid storable organic isocyanates containing carbodiimide and/or uretoneimine groups, comprising: (1) neutralizing acidic impurities in an organic isocyanate with an acid scavenger, in which the organic isocyanate comprises polymethylene polyphenylisocyanate comprising 90 to 100% by weight of diphenylmethane diisocyanate and 0 to 10% by weight of higher functional polyisocyanates of the diphenylmethane series, wherein the diphenylmethane diisocyanate comprises from 96 to 100% by weight of the 4.4′-isomer, from 0 to 1 % by weight of the 2,2′-isomer and from 0.1 to 4% by weight of the 2.4′-isomer, with the %'s by weight of the 4,4′-isomer, the 2.2′-isomer and the 2,4′-isomer totaling 100% by weight of monomeric diphenylmethane diisocyanate, (2) partially carbodiimidized isocyanate groups of the neutralized organic isocyanate with a phosphorous oxide catalyst and (3) terminating the carbodiimidization reaction by the addition of an acid comprising a silylated acid corresponding to the formula: X−[—Si(CH 3 ) 3 ] n wherein: X: represents the neutral acid residue obtained by removal of the acidic hydrogen atoms from an n-basic acid having a pKa value of at most 3, and n: represents an integer of 1 to 3.