Patent GB-887905-A (GB)
Title: Organopolysiloxane elastomeric foams
IPC: C08J9/08
Filed: 1960-09-23
Abstract: A process for preparing a cured elastomeric foam comprises mixing together (1) a polymer of the general formula <FORM:0887905/IV (a)/1> in which Ac is a saturated aliphatic monoacyl radical, R and R1 are each a monovalent hydrocarbon radical, a halogenated monovalent hydrocarbon radical or a cyanoalkyl radical and n is an integer of value at least 5, (2) from 1 to 50% by weight, calculated on the weight of (1) of an organic isocyanate free from active hydrogen and (3) water in amount greater than one molecule of water per isocyanate radical.  The radicals in the polymer (1) can, where appropriate, be as specified for the corresponding compound in Specification 862,576. Isocyanates specified are methyl, butyl, octadecyl and hexenyl isocyanate and hexamethylene diisocyanate; cyclohexyl, cyclohexenyl, xenyl, bromophenyl, anthracyl, p-dimethylaminophenyl, p-methoxy-, phenyl, naphthyl, 3,5-dichlorophenyl, and m- and p-nitrophenyl isocyanates; toluene, p,p1-diphenylmethane, and 3,31-dimethyl, dichloro or dimethoxy diphenylmethane diisocyanates.  In the foam may be incorporated fillers, such as powdered aluminium, tin, zinc, silicon, silica, mica, clay, iron oxide and titanium oxide and flame retardants such as antimony oxide, polychlorinated hydrocarbons and organic sulphanates.  In Examples (1) a base composition comprising a reaction product of hydroxy-end-blocked dimethylpolysiloxane and methyl triacetoxysilane, trimethylsiloxy end-blocked dimethyl polysiloxane, methylated silica aerogel, fume silica and TiO2 paste, is reacted with water and m-toluene diisocyanate to give a foam; (2) vinyl triacetoxy silane is used in place of the methyltriacetoxysilane of (1); (3) butyl, naphthyl, 2,5-dichlorophenyl, p-nitrophenyl isocyanates and p,p1-diphenylmethane and 3,31-dichloro-4,41-biphenylene diisocyanates are employed; (4) hydroxy-end-blocked 3,3,3-trifluoropropylmethyl polysiloxane or phenylmethyl polysiloxane is used as starting material.ALSO:A process for preparing a cured elastomeric foam comprises mixing together(1) a polymer of the general formula <FORM:0887905/V/1> in which Ac is a saturated aliphatic monoacyl radical, R and R1 are each a monovalent hydrocarbon radical, a halogenated monovalent hydrocarbon or a cyanoaklyl radical and n is an integer of value at least 5, (2) from 1 to 50% by weight, calculated on the weight of (1), of an organic isocyanate free from active hydrogen and (3) water in amount greater than one molecule of water perisocyanate radical.  The radicals in the polymer (1) can, where appropriate, be as specified for the corresponding compound in Specification 862,576.  Isocyanates specified are methyl, butyl, octadecyl and hexenyl isocyanates and hexamethylene diisocyanate; cyclohexyl, cyclohexenyl, xenyl, bromophenyl, anthracyl, p-dimethyl-aminophenyl, p-methoxyphenyl, naphthyl, 3,5-dichlorophenyl, and m- and p-nitrophenyl diisocyanates; toluene, p,p1-diphenylmethane and 3,31-dimethyl, dichloro or dimethoxy-diphenylmethane diisocyanates.  In the foam may be incorporated filters, such as powdered aluminium, tin, zinc, silicon, silica, mica, clay, iron oxide and titanium oxide and flame retardants such as antimony oxide, polychlorinated hydrocarbons and organic sulphamates.