Adhesion control for safety glass laminates via polyurethane composition

Claim 1

A polyurethane composition comprising the reaction product of a polyisocyanate or a polythioisocyanate and a compound containing at least two groups which are reactive with the isocyanate or thioisocyanate groups; said polyurethane composition containing from about 0.01 to 0.30 percent by weight based on the weight of the polyurethane composition of an organic phosphorus acid selected from the class consisting of: ##EQU8## where R is an alkyl containing from 1 to 18 carbon atoms, alkyl, alkaryl, alkoxy, aryloxy or an alkaryloxy group and may be linked directly to the phosphorus atom or linked by means of an oxygen atom, m and p are integers of from 1 to 2 and m + p must equal 3, and from 0.05 to 0.5 percent by weight of an organo-functional silane having the structural formula: (R).sub.m -- Si -- (X).sub.n wherein m and n are whole integers of from 1 to 3 and m + n is equal to 4, wherein X is a group which can hydrolyze to yield a hydroxyl group and R is an organic moiety selected from the class consisting of alkyl groups containing from 1 to 5 carbon atoms, aryl, vinyl and epoxy-containing organic moieties present in amounts sufficient so as to control the degree of adhesion of the polyurethane composition, when in sheet form, to glass; the weight ratio of organic phosphorus acid to organo-functional silane being from about 0.05 to 0.80:1 inclusive; said polyurethane being characterized as having a degree of adhesion to glass of about 1 to 10 pounds per lineal inch when a sheet of said polyurethane is laminated to a sheet of glass, said degree of adhesion being maintained when the laminate is subjected to 100 percent humidity, and 120°F., for at least 5 days.