Abstract: A polymerizable composition comprising an ethylinically unsaturated isocyanurate resin at least one vinyl monomer copolymerizable therewith. The isocyanurate resin is the trimerized reaction product of an ethylenically unsaturated, isocyanate functional urethane composition derived from the reaction of a polyisocyanate composition comprising a mixture of 2, 4'- and 4, 4'- diphenylmethane diisocyanates with at least one hydroxyl functionalized vinyl monomer. The polymerizable compositions are clear resins which can be reaction injection moulded to produce moulded articles having a high heat distortion temperature.

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: A melamine-aldehyde-phosphate condensation product which is useful as a fire-retardant, especially for plastics materials, and which is made by reacting melamine and at least one aldehyde, or a condensate of melamine and at least one aldehyde, with at least one oxyacid of phosphorus or precursor therefor or ester thereof until the condensation product is essentially non-acidic, the proportions of melamine and aldehyde being chosen such that the molar ratio of units derived from melamine: units derived from aldehyde in the condensation product is in the range 1:1.5 to 1:4.5, and the proportions of melamine and oxyacid of phosphorus or precursor therefor or ester thereof being chosen such that the molar ratio of units derived from melamine:phosphorus in the condensation product is in the range 1:0.4 to 1:1.7.

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.