Adhesion between addition‐curable silicone elastomer and nylon using diallylbisphenol A as adhesion promoter

Abstract

AbstractIt was found that the incorporation of a small amount of 2,2′‐diallylbisphenol A in a two‐component room‐temperature vulcanizing (RTV) silicone produced excellent adhesion on nylon substrates, whereas no adhesion was observed when this additive was excluded from the formulation. The effect of the chemical structure and the functionalities of this adhesion promoter were investigated by evaluation of several other molecules bearing both allylic and phenolic groups. No adhesion improvement was observed when 2‐allyl 4‐cumylphenol or 2‐allylphenol was used as the adhesion promoter, whereas with 2‐allylbisphenol A there was good adhesion between the two surfaces. Although it is quite clear that allyl groups react with the adhesive through the hydrosilylation reaction during the cure process of the RTV material, the interaction of the phenolic group with polymer surfaces seems to be largely dependent on the steric effect, that is, the ability of the OH group to be close enough to the plastic surface to develop a strong hydrogen bond. The minimum temperature required for adhesion to occur between nylon and RTV was determined to be in the range of 50°C–60°C. This temperature corresponds to the glass‐transition temperature of the amorphous part of the nylon. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 89: 3496–3499, 2003