Title: Polyurethanes

 Number/Link: GB944310

Applicant/Assignee: Imperial Chemical Industries

Publication date: 11-12-1963

“Gist”: Non-isocyanate polyurethanes by transurethanization of bis-carbamates and polyols.

Why it is interesting: Because of the growing concern over isocyanate toxicity and related changes in legislation, research and development of non-isocyanate polyurethane (NIPU) systems has increased sharply over the last few years. The idea, and most of the chemistry of NIPU is by no means new. In this patent, filed by ICI in 1961, NIPU is prepared by transesterification of bis-carbamates and polyols with a functionality of 2 or more. The materials are said to be especially useful for coatings and as TPU for fiber production. According to the patent, the advantages of this reaction system over the use of isocyanates are the reduction of the toxicity hazard, less moisture sensitivity and no need to carefully control reaction conditions and reactant proportions.  In an example N,N’-methylene-bis-urethane was reacted with 1,4-butanediol catalyzed by DBTDL resulting in a TPU which could be melt-drawn into fibers.  (Note that, in this case, ‘urethane’ is the common name for ethylcarbamate).

ICI logo anno 1961