Method and apparatus for producing shipping rolls of wrinkle free composite sheet material

The method of forming a given length of continuous length resin composite sheet material having thermoplastic film surfaces and a filament network core material inbetween comprising

• providing a large diameter rotatable forming drum for assembly of said composite sheet material, said drum having a diameter in the range of 30 to 100 inches,
• feeding from a source a first thermoplastic resinous facing film to said drum,
• feeding a continuous layer of core material of continuous filament strands to said drum for association with said first facing film,
• feeding a second thermoplastic resinous facing film to said drum for association with the opposite side of said core material to form the assembly of said composite sheet material,
• feeding from a source a layer of separator material inbetween wraps of said composite sheet material as they are wound on said drum,
• winding a number of wraps of said composite sheet material and separating material on said drum,
• subjecting the wraps of said composite sheet material on said drum to pressure and to heat to integrate the components of said assembly into interbonded relation,
• maintaining said heat and pressure on said assembly for a cycle period adequate to integrate said components into an integrated dimensionally stabilized cured composite sheet,
• providing in said method a forming drum with a sufficiently large diameter such that said winding of said given length of composite sheet material is stacked to a dimension sufficiently thin relative to the diameter of said drum that the differential in compression of said composite under heat and pressure is sufficiently low that the cured composite material is free of surface wrinkles and creases.