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Abstract

A method of making a composite board comprising (a) applying a layer of a first composition comprising a thermosetting resin and a catalyst therefor to the surface of a mould; (b) allowing the thermosetting resin to polymerize; (c) applying a layer of a connecting composition comprising an adhesive or a second composition of thermosetting resin and catalyst to the layer (a); and (d) placing a structure comprising one or more laminae on the connecting composition, each lamina comprising first and second sheets of material fibre material and a corrugated sheet or a cellular core of natural fibre material sandwiched between the first and second sheets, the lamina being impregnated with thermosetting resin, extender and catalyst; the thermosetting resin being polymerized on the layer of step (c); (e) allowing the connecting composition to set and removing the composite board from the mould. An alternative to (d) and (e) involves (f) applying to the layer of (c), a layer of fibrous reinforcing material welted with thermosetting resin and catalyst, allowing the resin to polymerize and allowing the connecting composition to set so as to form an intermediate composite which is removed from the mould. The structure of (d) is then applied to the free side of the intermediate composite using a layer of the connecting composition of step (c) and the connecting composition is allowed to set to join the structure to the free side of the intermediate composition to form the composite board.

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First Claim