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AssigneeBayer Aktiengesellschaft
InventorsRichard Kopp, Gerhard Grogler, Max Mann
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This invention relates to solid reaction products of aliphatic, cycloaliphatic or araliphatic mono- and/or polyisocyanates and organic, weakly acid mono- and/or polycarboxylic acids for the production of cellular plastics articles and particularly polyurethane foams. The products of the present invention may also be in the form of mixtures with carboxylic acids. The products are suitable for the production of cellular or porous plastics articles, but are preferably used in the preparation of cellular thermoplastic polyurethanes and semi-rigid and particularly rigid polyurethane integral skin foams having a compact outer skin formed by foaming the reaction mixture in closed molds.
In a process for the preparation of cellular plastic products comprising blowing said plastic with a blowing agent, the improvement wherein said blowing agent comprises a mixed anhydride which has a melting point of at least 40.degree. C. and is obtained by the reaction of (a) mono- and/or polyisocyanates bound to aliphatic, cycloaliphatic or araliphatic radicals and (b) weak mono- and/or polycarboxylic acids with PK.sub.1 -values of from 4 to 7, and wherein said blowing agent is used in a quantity of from 0.05 to 20% by weight, and the blowing of said plastic is carried out at temperatures above 100.degree. C.
Dependencies are inferred from the claim text.