AbstractNitrile rubbers have often been used together with phenolic resins in molding materials to produce an impactresistant product. These mechanical mixtures may react during final cure. Acrylonitrile–butadiene rubbers containing residual unsaturation can, however, be coreacted with phenolic resins during the early stages of polymerization if appropriate conditions are adopted. The coreaction probably occurs via formation of a chroman from a double bond in the rubber and ano‐methylol phenol. The coreaction products are completely soluble in alcohol, whereas the rubbers are not. Laminates made from these coreaction products are flexibilized to the point at which they lend themselves well to cold punching. Yet the rubber, being tightly bound, cannot be extracted with solvents nor lead to blistering on heat
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