new polyisocyanatmischungen and their use in the production of soft polyurethane foams.

摘要

Soft polyurethane foams are produced by reacting … …  a) a polyisocyanate mixture comprising … …  A) 21 - 95% by weight of tolylene diisocyanate and …  B) 5 - 79% by weight of a mixture of diphenylmethane diisocyanates and polyphenylpolymethylene polyisocyanates, comprising … …  1.) 55 - 87% by weight of 4,4'-diphenylmethane diisocyanate, …  2.) 8 - 30% by weight of 2,4'-diphenylmethane diisocyanate, …  3.) 0 - 4% by weight of 2,2'-diphenylmethane diisocyanate and …  4.) 5 - 35% by weight of polyphenylpolymethylene polyisocyanates, … … with …  b) compounds having a molecular weight of 400 - 10,000 and containing at least two hydrogen atoms which are active towards isocyanates, and optionally …  c) chain extenders and crosslinking agents having a molecular weight of 32 - 399 and containing at least two hydrogen atoms which are active towards isocyanates, in the presence of …  d) water as blowing agent, and optionally in the presence of …  e) other blowing agents, catalysts and further assistants and additives which are known per se. …