GB1533308A - High resiliency polyurethane foam with breathability and reduced shrinkage by use of certain tin catalysts - Google Patents

Abstract

1533308 High resiliency polyurethane foams M & T CHEMICALS Inc 6 Dec 1976 [22 Dec 1975] 50671/76 Heading C3R A method for preparing a high resiliency polyurethane foam having a value for ILD 65% / ILD 25% greater than 2À0 comprises reacting an isocyanate component having a functionality of from 2À2 to 2À8 and consisting of a mixture of a monomeric diisocyanate and a polymeric, polyfunctional isocyanate and at least one polyol selected from (1) polyols having a molecular weight greater than 3000 and an OH number of 25 to 56, and containing 5 to 30% wt., based on the weight of said polyol, of side chains derived from the polymerization of acrylonitrile or a mixture of acrylonitrile and styrene, or (2) mixture of polyols having a molecular weight between 4000 and 6000, with 0À5 to 6À0% wt. of at least one diamine as crosslinker, based on the weight of polyol, in the presence of water as a blowing agent, a blowing catalyst, a siliconebased surfactant, and, as a polymerization catalyst, 0À001 to 0À10% wt, based on the weight of said polyol, of an organo tin compound of the formula R 2 Sn(OCOR<SP>1</SP>COOR<SP>11</SP>) 2 , wherein each of R and R<SP>11</SP> is a C 1 -C 20 -alkyl radical, R 1 is selected from C 2 -C 20 - alkylene and alkenylene radicals, cycloalkylene and phenylene radicals, with the proviso that the molar ratio of NCO groups to active hydrogen atoms present in the reaction mixture is 0À90 to 1À15. The blowing catalyst may be a tertiary amine. Suitable monomeric diisocyanates are tolylene diisocyanate, alkylene 4,41-diphenylmethane diisocyanate or naphthalene diisocyanate. The polymeric polyisocyanate is typically polymethylene polyphenyl isocyanate. Suitable polyols (2) are OH- terminated polyesters, polyethers, polyamides, polymercaptans, polyamines, and polyisocyanate-modified alkylene glycols and polyesters. The blowing agent preferably contains 2-4% wt. of water and 0-10% wt. of a volatile fluorinated hydrocarbon that boils at from -40‹ to 70‹ C., the percentages being based on the weight of the polyol. In the example high resiliency polyurethane foams are prepared by the one-shot method from a formulation comprising 2,4- and 2,6- tolylene diisocyanates, polymethylene polyphenyl isocyanate; an ethylene-oxide-capped polypropylene oxide polymerized on glycerine (M.Wt. 4700, OH number 27); the above polyol containing grafted acrylonitrilestyrene copolymer; water, a siliconebased surfactant; N-ethyl-morpholine, bis(N,N- dimethylaminoethyl)ether and triethylene diamine and any one of the following polymerization catalysts: dibutyltin bis(isoocytl maleate), dibutyltin bis(isooctyl succinate) and dimethyltin bis(isooctyl maleate).