Process for the manufacture of polyurethanes

1,127,605. Polyurethanes. IMPERIAL CHEMICAL INDUSTRIES Ltd. 14 Oct., 1965 [27 Oct., 1964], No. 43820/64. Headings C3C and C3R. Polyurethanes are prepared by reacting an organic polyisocyanate with an hydroxyl groupcontaining polyester which contains in the molecule a group of the formula wherein n is 0, 1 or 2, optionally in the presence of a gas-generating agent. The polyester is suitably a reaction product of a polyhydric alcohol, a polycarboxylic acid and a compound of the formula R1-NH.CO.NH-R11, where R1 and R11, which may be the same or different, are hydrogen, a hydroxyalkyl group, a hydroxyalkoxyalkyl group or a-CO.NH 2 or -CO.NH.Q group, where Q represents a hydroxyalkyl or hydroxyalkoxyalkyl group. Particularly suitable compounds containing the urea grouping are urea, methylol derivatives of urea and glycol ethers of the methylol derivatives and symmetrical bis(hydroxyalkyl) ureas. Conventional aliphatic, cycloaliphatic and aromatic polyisocyanates may be reacted with the polyester and the reaction may be carried out in the presence of water and/or low b.p. liquid blowing agents, tertiary amine and/or organic compounds of metals as catalysts, surface-active agents or organic solvents. In examples polyesters are prepared from (1) a formalin/urea reaction product, diethylene glycol and adipic acid, (2) urea, adipic acid and diethylene glycol, and (4) a urea/ethanolamine reaction product, diethylene glycol and adipic acid.