Document Type and Number:
Japanese Patent JPS4953695
Kind Code:
A
Abstract:
1443055 Polyurethane foams UNION CARBIDE CORP 10 Aug 1973 [11 Aug 1972] 37983/73 Heading C3R Open-cell rigid polyetherurethane foams having a closed cell content of less than 50% are prepared from a mixture comprising (a) a polyether polyol preferably having an average M.W. of 200 to 1500 and a hydroxyl number of 200 to 1000, (b) an organic polyisocyanate, (c) a blowing agent, (d) a catalyst for polyurethane formation and (e) as a cell-opening agent, an essentially linear siloxane-oxyalkylene (AB) n block copolymer wherein the average M.W. of each siloxane block ranges from 500 to 10,000, the average M.W. of each polyoxyalkylene block ranges from 300 to 10,000, the siloxane blocks preferably constitute 20 to 50 weight per cent of the copolymer, the polyoxyalkylene blocks preferably constitute 80 to 50 weight per cent of the copolymer, and the block copolymer has an average M.W. of at least 65,000 when the polyoxyalkylene block and siloxane block are bonded by a silicon to oxygen to carbon linkage, and an average M.W. of at least 30,000 when the two blocks are bonded by a silicon to carbon linkage. The cell opening agent is most preferably a block copolymer of the formula wherein R is a hydrocarbon radical free from aliphatic unsaturation, preferably a methyl radical, n is 2, 3 or 4, x is an integer of at least 7, y is an integer of at least 4, and d is an integer of at least 4. The radical (C n H 2n O) preferably represents a mixture consisting of 30 to 75% by weight of oxyethylene groups and 70 to 25% by weight of oxypropylene groups. All other components of the reaction mixture are those conventionally used in the art and the foams may be prepared by conventional one-shot or prepolymer processes.
Application Number:
JP8935273A
Publication Date:
May 24, 1974
Filing Date:
August 10, 1973
Export Citation:
International Classes:
C08G18/00; C08G18/48; C08J9/00; (IPC1-7): C08G22/14