| 摘要 |
A method of forming a one-shot urethane foam from a polyol resin material and a polyisocyanate material in which one of the materials is premixed with one or more catalysts and a blowing agent, for instance, a volatilizable liquid blowing agent to form a pre-mixture, and the premixture is introduced into a mixing chamber together with the other one of the materials resulting in the formation of a reaction mixture which is then dispensed into a container for completion of the reaction between the polyol and the polyisocyanate to form a porous urethane foam, is characterized in that the premixing of the one material with the catalyst and the blowing agent and the mixing of the thus obtained premixture with the other one of the materials is effected at a pressure which lies above atmospheric pressure and below about 150 p.s.i.g. An apparatus for carrying out the method is described. Suitable resin polyols are polyethers and polyester diols and triols of M.W. 300 to 4500. Triethylamine, triethylene diamine, N-ethyl- or methyl-morpholine, stannous octoate, stannous oleate and dibutyltin diacetate, di-(2-ethyl hexoate) and dilaurate are suitable catalysts. With stannic valence tin compounds dextrorotatory tartaric acid is preferably used to prevent degradation of the foam. |
