Resinification by a grafting technique

Pre-B-stage resinous products are made by reacting at an elevated temperature a liquid homopolymer of a C4-C6 conjugated diolefin (or a liquid copolymer thereof with a minor proportion of an ethylenically unsaturated monomer), and a polymerizable ethylenically unsaturated cross-linking agent, in the presence of a peroxide catalyst. Diolefin polymers specified are those of butadiene, hexadiene, isoprene, dimethyl butadiene, pipeidrine and methyl pentadiene and copolymers thereof with styrene, methyl and dimethyl styrenes, acrylonitrile and methyl ethyl ketone. Unsaturated cross-linking agents specified are styrene, vinyl toluene halostyrenes, vinyl naphthalenes, alkyl acrylates and methacrylates, diethyl fumarate, acrylonitrile, vinyl chloride and vinylidene chloride. Peroxide catalysts specified are dicumyl peroxide, di-tert. butyl peroxide, benzoyl peroxide, and mixtures thereof. The products may be used in conjunction with reinforcing materials in the preparation of laminates. This is preferably effected either by combining the p reinforcing material with the pre-B-stage mix followed by thermally curing the resultant mass, or by combining the pre-B-stage product with the reinforcing material in the presence of additional cross-linking agent and then curing the mass. The reinforcing material is preferably glass fibre, but may also be asbestos, mica, rock, cotton, linen, rayon, silk, hair, nylon, iron, aluminium or copper. When using glass fibre the resinifiable mix may include an unsaturated silane ester.