GB875109A - Organosilicon resins - Google Patents

Abstract

An organosilicon polymer is made by reacting (1) a siloxane of the general formula: <FORM:0875109/IV (a)/1> wherein each R is a monovalent hydrocarbon (saturated or unsaturated) or halogenated hydrocarbon radical, n has an average value of from 1,0-1,9 inclusive, each R1 is a divalent aliphatic hydrocarbon or polyoxyalkylene radical and y has an average value of from 0,05-0,5 inclusive, with (2) an organic polyisocyanate, many examples of which are given, which may also contain substituents, e.g. sulphone, nitrile, halogen or nitro groups. Reaction occurs spontaneously on mixing and the resulting polymers will air dry in from 2-24 hours. Compounds (1) are best made by reacting a siloxane containing Si-bonded alkoxy or hydroxy radicals with a diol of the formula HO,R1,OH in the presence or absence of a catalyst, e.g. HCl or 2-ethylhexoic acid, R1 being a saturated aliphatic, ethylenically or acetylenically unsaturated aliphatic, or a polyoxyalkylene radical. In typical examples, (Ph=phenyl; Me=methyl), (1) ethylene glycol was reacted with: <FORM:0875109/IV (a)/2> in the presence of aqueous HCl as catalyst, by heating to 160 DEG C., the methanol formed being distilled off. The resulting siloxane was then cured by adding toluene diisocyanate and triethylamine as curing catalyst; (2) a mixture of a toluene solution of a Ph,Me-, mono Me- and mono Ph-siloxane copolymer containing Si-OH groups, ethylene glycol and 2-ethylhexoic acid was heated at 160 DEG -198 DEG C. water produced being distilled off, to give a product which was diluted with xylene and mixed with toluene diisocyanate. The resulting solution was applied to wood and metal panels.