GB791956A - Reaction products of polymers with polyisocyanates or polyisothiocyanates - Google Patents

Abstract

Synthetic elastomers are prepared from a reaction product of a polyester, polyether or polyesteramide and a polyisocyanate or polyisothiocyanate in admixture with an acid ester of a phosphoric acid by neutralizing the acid ester which retards setting of the reaction product and then moulding the mixture. The stabilized mixtures retain the capacity for being milled to form sheets for long periods. Pre ferred esters are the mono- and di-alkyl esters of orthophosphoric acid, the alkyl groups of which contain 2-18 carbon atoms. Polyisocyanate may be reacted with polyester in two stages-one before addition of the acid ester and the other before its neutralization. If desired an organic acid chloride may be added to the reaction mixture as described in Specification 790,543. Preferably the acid phosphate is added to the hot reaction product and the acid chloride added by subsequent cold milling. Suitable bases for neutralizing the acid phosphates are diphenylamine, p-phenylenediamine, diphenylguanidine, guanidine, aniline, piperidine, benzylidene, dipiperidine, aminopyridine, 2,2 - dipyridylamine, 2 - amino - 4,6-dimethylpyridine, urea, hexamethylene tetramine, hydrazine hydrate, magnesium oxide, calcium hydroxide, and ammonium carbonate. In the Examples: (1) hot dehydrated polyethylene glycol wax mixed with naphthalene-1.5-diisocyanate followed by 1.4-butylene glycol as a cross-linking agent. Butyl acid phosphate was added. The mixture was heated, milled and divided into four parts which were milled to give sheets after various periods of storage, the sheets being moulded after neutralization of the acid phosphate with diphenylamine; (2) is similar to (1) but the cross-linking agent was added as an amine or mixture of amines in excess of the amount required to neutralize the butyl acid phosphate; (3) is also similar but employs a mixture of mono-ethyl and di-ethyl hydrogen phosphates; (4), (5) and (6) are similar to (2) but illustrate the addition of p-nitro-benzoyl chloride as well as butyl acid phosphate.