POLYMERIC ALLOPHANATES OF DIPHENYLMETHANE DIISOCYANATE, PREPOLYMERS OF THESE POLYMERIC ALLOPHANATES, AND PROCESSES FOR PREPARATION OF POLYMERIC ALLOPHANATES AND PREPOLYMERS THEREOF

摘要

PURPOSE: An alcohol or diol based allophanate-modified MDI which is further converted to a higher functionality allophanate product referred to as polymeric allophanates, prepolymers of these polymeric allophanates, a process of making and using the polymeric allophanates, and a process of making and using the prepolymers of the polymeric allophanates are provided. CONSTITUTION: The process for the production of a polymeric allophanate based on diphenylmethane diisocyanate having an NCO group content of 12 to 30% by weight, comprises (I) reacting: (1) one or more OH-group containing compounds selected from the group consisting of: (a) aliphatic alcohols, (b) aromatic alcohols, (c) aliphatic diols and (d) mixtures thereof; and (2) diphenylmethane diisocyanate comprising: (a) from 0 to 60% by weight of 2,4'-diphenylmethane diisocyanate, (b) less than 6% by weight of 2,2'-diphenylmethane diisocyanate, and (c) the balance being 4,4'-diphenylmethane diisocyanate, with the %'s by weight of (2)(a), (2)(b) and (2)(c) totaling 100% by weight of (2), in the presence of: (3) one or more allophanate catalysts, at temperatures of about 80 to about 110 deg.C to form (A) an allophanate-modified diphenylmethane diisocyanate; and (II) cooling (A) the allophanate-modified diphenylmethane diisocyanate to a temperature of about 20 to about 70 deg.C for about 1 hour to about 30 days, thereby forming (B) a polymeric allophanate based on diphenylmethane diisocyanate. The polymeric allophanate based on diphenylmethane diisocyanate is characterized in that it has an NCO group content of 12 to 30%, and comprises (A) an allophanate modified isocyanate based on MDI, having an NCO group content of 20 to 32% and which comprises the reaction product of: (1) one or more OH-group containing compounds selected from the group consisting of (a) aliphatic alcohols, (b) aromatic alcohols, (c) aliphatic diols, and (d) mixtures thereof; and (2) diphenylmethane diisocyanate comprising: (a) from 0 to 60% by weight of 2,4'-diphenylmethane diisocyanate, (b) less than 6% by weight of 2,2'-diphenylmethane diisocyanate, and (c) the balance being 4,4'-diphenylmethane diisocyanate, with the %'s by weight of (2)(a), (2)(b) and (2)(c) totaling 100% by weight of (2), in the presence of (3) one or more allophanate catalysts; wherein (A) the allophanate-modified isocyanate based on MDI is held at a temperature of from about 20 to 70 deg.C from about 1 hour to about 30 days to form (B) the polymeric allophanate based on diphenylmethane diisocyanate.