Manufacture of polymers containing biuret and urea groups

摘要

Isocyanate based polymers containing biuret and urea groups are prepared by reacting an organic polyisocyanate and water in the presence of a polyaldimine or polyketimine derived from a polyamine by reaction with an aldehyde or ketone. The polyisocyanate may be an aliphatic, cycloaliphatic or aromatic monomer or a prepolymer derived from a polyhydric polyether or polyester and an excess of isocyanate. The polyaldimine or polyketimine may be derived from a ketone or aldehyde of B.P. less than 180 DEG C., and either the polyamine or aldehyde or ketone may be sterically hindered. The reaction between the isocyanate and water may be performed in air containing water vapour or in a solvent. The product may be a plastic, rubber or foam, in the latter case a blowing agent may be included. In a typical example (1) a solution containing (i) an -NCO ended prepolymer derived from polyethylene/propylene adipate and diisocyanatomethyl-cyclohexane and (ii) the bisketimine from methyl isobutyl ketone and m-xylylene diamine was poured in to a glass surface and the solvent evaporated.