Abstract: A polymerisable composition which comprises an unsaturated urethane, a C.sub.1 or C.sub.2 alkyl methacrylate and at least one other ethylenically unsaturated addition polymerisable substance copolymerisable therewith, such polymerisable compositions, where they contain an inorganic filler, overcome some of the problems associated with the polymerisable compositions described in European 0.064,809. Where the polymerisable substance comprises an unsaturated polyester, the shelf-life of the polymerisable composition can be extended by adding thereto a reagent which reacts with a portion of the free carboxyl group in the unsaturated polyester. The compositions may be used, for example, in the production of fibre-reinforced composites.

Abstract: Moulded plastics products are produced by in-mould copolymerization of methyl methacrylate with a polyurethane polyacrylate or polymethacrylate derived from a hydroxyalkyl acrylate or methacrylate by reaction of hydroxyl groups thereof with the isocyanate groups of a polyisocyanate or urethane polyisocyanate having isocyanate functionality greater than 2.0.

Abstract: Moulded plastics products are produced by in-mould copolymerization of methyl methacrylate with a polyurethane polyacrylate or polymethacrylate derived from a hydroxyalkyl acrylate or methacrylate by reaction of hydroxyl groups thereof with the isocyanate groups of a polyisocyanate or urethane polyisocyanate having isocyanate functionality greater than 2.0.