Method of producing a formable composite material

A method of producing a rigid thermoplastic composite article comprising the steps of:

• (a) simultaneously laying monofilaments or tows of a reinforcing material from first supply means side-by-side with monofilaments or tows of thermoplastic material from second supply means to form a first layer consisting of interspersed unidirectional nonbonded and nonwoven monofilaments or tows of reinforcing material and thermoplastic material in substantially parallel relationship;
• (b) simultaneously laying monofilaments or tows of a reinforcing material from third supply means side-by-side with monofilaments or tows of thermoplastic material from fourth supply means to form a second layer consisting of interspersed unidirectional nonbonded and nonwoven monofilaments or tows of reinforcing material and thermoplastic material in substantially parallel relationship;
• (c) superimposing said second layer upon said first layer with the monofilaments or tows in said second layer extending in a different direction to the monofilaments or tows in said first layer;
• (d) thereafter stitching said layers together using knitted stitches to hold said monofilaments or tows in said first and second layers in fixed relation to one another;
• (e) forming said stitched layers into a retainable complex shape at room temperature;
• (f) retaining said complex shape, and heating and cooling the same to harden said thermoplastic material to produce said rigid thermoplastic composite article;
• and
• (f) at some time during the process agitating the monofilaments or tows of reinforcing material and thermoplastic material in each layer to effect an intimate and substantially uniform mixing of the filaments of reinforcing material and thermoplastic material in each layer.