Fibre reinforced thermoplastic sheet for hot pressing - is made with surface layer containing a parting agent e.g. waxes, metallic soaps, silicone(s), fluorocarbon(s), oils, etc.

摘要

Sheet material made of textile reinforcing fibres in a thermoplastic matrix has at least one outer layer, up to 500 microns thick, which contains a parting agent. It is made in a continuous or discontinuous process where the textile reinforcing structure is impregnated with a thermoplastic while at the same time, or in a second step, at least one surface layer of the same thermoplastic but containing a parting agent is applied. The surface layer is pref. applied in the form of a film containing the parting agent, but it can also be applied as a solution or in powder form. It is pref. applied under heat and pressure and the whole assembly can be made in a continuous process on a double band press. Suitable parting agents which prevent adhesion between the die surfaces and the thermoplastic are waxes, metallic soaps, silicones, fluorocarbons, oils, etc. USE/ADVANTAGE - The material reduces the cycle time required in press forming as no separate parting agent need be applied to the metallic die surfaces.