Why it is not recommended to apply pressure-sensitive adhesives onto solid EPDM rubber, low durometer (10 to 40 Shore A) Neoprene and Buna-N?

EPDM compounds often contain certain chemical additives, such as paraffins, which migrate to the surface over time. When this happens, an adhesive backing will likely get peeled from the surface. Although the adhesive will stay onto the gasket surface for a few days, over time the adhesive it will begin to separate due to the migration of oils and plasticizers. Although this bloom effect often benefits the resistance of EPDM to sunlight, acids and other conditions - long term bonding is made difficult. Low durometer neoprene and Buna-N compounds often contain oils and plasticizers that make these surfaces difficult to bond to. If your application requires one of these materials with an adhesive backing, the adhesive should only be counted on as a temporary assembly aide. These adhesive applied gaskets must be applied immediately, and the design must include bolt holes such that mechanical fastening is the prime method of maintaining the position of the gasket in final assembly.