Patent GB-923677-A (GB)
Title: Cellular polyurethane plastics
IPC: C08G18/66
Filed: 1960-07-12
Abstract: A process for the preparation of a cellular polyurethane plastic having a 25% compression deflection property at rest within the range of from 0,5 lbs./sq. in. to 6 lbs./sq. in. and a density within the range of from 1,5 lbs./cu. ft. to 7 lbs./cu. ft. comprises reacting (1) from 0,5 to 2,5 weight per cent water, (2) from 20 to 40 weight per cent of an organic diisocyanate and (3) from 59,5 to 79,5 weight per cent of a mixture of from 72 to 90 weight per cent of polyhydric polyalkylene ether having a molecular weight within the range of from 1000 to 5000 and of from 10 to 18 weight per cent of a tetrahydric organic compound which is pentaerythritol, 1, 2, 4, 5-hydroxypentane, N,N,N1, N1-tetrakis-(2-hydroxypropyl)-ethylene diamine or hexamethylene diamine, the composite hydroxyl number of the mixture of the polyalkylene compound and the tetrahydric compound being within the range of from 125 to 180 and the sum of the weights per cent of (1), (2) and (3) being 100 and the isocyanate index being from 90 to 120.  The polyhydric polyalkylene ether and the tetrahydric compound may be reacted separately; for example, the polyalkylene compound may be first reacted with the organic diisocyanate to form a prepolymer which is then reacted with the tetrahydric compound and the water.  Isocyanate index means the percentage of isocyanate used in relation to the amount necessary to react with all the active hydrogen in the reaction mixture. Preferably the reaction mixture contains also an organosiloxane, especially a siloxane oxy alkylene block copolymer.  Suitable catalysts for the reaction are N,N1-dimethyl piperazine, N-ethyl or methyl-morpholine and triethylene diamine.  The polyether may be a polymerization product of one or more alkylene oxides or a reaction product of the latter with a polyol.  Suitable polyisocyanates include those disclosed in Specification 769,682.  A preferred embodiment comprises reacting 0,8% by weight of water, 25 parts toluene 2, 4 and 2, 6-diisocyanates (80:20), and 71 parts of a mixture of 15 parts of N,N,N1,N1-tetrakis (2-hydroxypropyl) ethylene diamine and 85 parts of a trihydric polyalkylene ether of molecular weight 3000.  The polyhydric polyalkylene ether may be a polyalkylene oxide or a reaction product of an alkylene oxide with a tri- or tetra-hydroxy compound.ALSO:A process for the preparation of a cellular polyurethane plastic having a 25% compression deflection property at rest within the range of from 0,5 lbs./sq. inch to 6 lbs./sq. inch and a density within the range of from 1,5 lbs./cu. ft. to 7 lbs./cu. ft. comprises reacting (1) from 0,5 to 2,5 weight per cent. water, (2) from 20 to 40 weight per cent. of an organic diisocyanate, and (3) from 59,5 to 79,5 weight per cent. of a mixture of from 72 to 90 weight per cent. of polyhydric polyalkylene ether having a molecular weight within the range of from 1000 to 5000 and of from 10 to 18 weight per cent. of a tetrahydric organic compound which is pentaerythritol, 1, 2, 4, 5- hydroxypentane, N, N, N1 N1-tetrakis -(2-hydroxypropyl) -ethylene diamine or hexamethylene diamine, the composite hydroxyl number of the mixture of the polyalkylene compound and the tetrahydric compound being within the range of from 125 to 180 and the sum of the weights per cent. of (1), (2) and (3) being 100 and the isocyanate index (defined) being from 90 to 120.  the polyhydric polyalkylene ether and the tetrahydric compound may be reacted separately; for example, the polyalkylene compound may be first reacted with the organic diisocyanate to form a prepolymer which is then reacted with the tetrahydric compound and the water.  Preferably the reaction mixture contains also an organosiloxane, especially a siloxane oxyalkylene block copolymer. Suitable catalysts for the reaction are N, N1 -dimethyl piperazine, N-ethyl or methyl-morpholine and triethylene diamine.  The polyether may be a polymerization product of one or more alkylene oxides or a reaction product of the latter with a polyol.  Suitable polyisocyanates include those disclosed in Specification 769,682.  A preferred embodiment comprises reacting 0,8 by weight of water, 25 parts of toluene 2, 4 and 2, 6 -diisocyanates (80 : 20), and 71 parts of a mixture of 15 parts of N, N, N1, N1-tetrakis (2-hydroxypropyl) ethylene diamine and 85 parts of a trihydric polyalkylene ether of molecular weight 3000.  The polyhydric polyalkylene ether may be a polyalkylene oxide or a reaction product of an alkylene oxide with a tri- or tetrahydroxy compound.