Patent ID: 6280671
Filing Date: 2001-08-28
Classification: B29C,B29K,E01F,Y10T

Abstract:
A method for producing a multilayer plastic composite,said composite comprising a sequence of layers of at least two incompatible thermoplastic plastics, A and B, wherein said sequence of layers alternates between A and B, a layer of plastic B is discontinuous at regular intervals to form gaps in said layer of plastic B, and said gaps in said layer of B are filled in with plastic A;said method comprising coextruding plastic A and plastic B through a die comprising a pair of parallel exit slits and a plurality of exit ports, with a gap between each port, located between said pair of parallel exit slits, said plurality of exit ports being evenly spaced along a line parallel to said pair of exit slits,wherein said coextruding plastic A and plastic B comprises forming a pair of fluid streams of said plastic A by passing a fluid stream of plastic A through said pair of parallel exit slits and forming a plurality of fluid streams of plastic B with gaps between each stream of said plastic B by passing a fluid stream of plastic B through said plurality of exit ports, so that said fluid streams of said plastic A exit said pair of exit slits and said fluid streams of plastic B exit said plurality of exit ports in such a manner to result in a portion of said fluid streams of said plastic A passing through said gaps between each stream of said plastic B to effect fusion of said pair of fluid streams of said plastic A, to obtain said composite.