Rubber Adhesive Made
It will be clear that rubbers and phenol formaldehyde resin differ in most respect. And because they widely, a variety of properties can be obtained by blending them, adhesives, for example, can be made with certain desirable features in which individually the resin and rubber are deficient. Briefly, the resin reduces extensibility of the rubber whilst increasing its cohesive strength.The first reference to the use of a combined resin and rubber adhesive was probably the patent that granted over thirty years ago describing bonding to metal, porcelain and glass with a rubber or rubberlike substance mized with a synthetic resin. Since the publication of this patent many rubber and rubberlike substances have no doubt been examined as adhesives in association with a thermosetting resin, especially a phenolic resin. Experience has shown that the most important rubber is nitrile rubber, and its behavior in a two polymer adhesive is in a number of ways rather like that of the polyvinyl acetals discussed previously, some of the comments made in the previous section therefore apply here.