two preformed materials such as paper , fabrics , glass , sheet metal , at least one of which is pervious to water vapor , are joined together with a solvent - free adhesive based on a latex of a rubbery polymer . the latex is one which is stabilized with an emulsifier which forms water - insoluble compounds with zinc or cadmium ions . included in the adhesive formulation is an ammonium or amine salt gelling agent for the latex , a zinc or cadmium ion donor compound and sufficient ammonia or a compound which releases ammonia to provide a ph of above 8 to the adhesive formulation . a surface of at least one of the preformed materials is coated with the adhesive and then contacted with a surface of the other material and held in such contact while heating to gel the latex and evaporate the water from the intersurface layer of adhesive .