Method of fabricating composite products
AssigneeOy Wiik & Hoglund AB
InventorsHans Hede, Gunnar Blomqvist, Jarl-Erik Jofs
Life of this patent
Estimating the term…
Abstract
The invention provides a method of forming composite products of two incompatible plastics or other materials by extruding a first stream of plastic through a die to form a profile and coextruding another stream on the surface thereof which is fusible with the first plastic and is impregnated with foreign matter and causing, by means of high heat, pressure drop or shear stress, a rupture of the layer to form a pattern of irregular cavities and projections to which a coating can be applied which will invade the cavities and surround the projections to bond with the extruded profile.
Claims7
A method of fabricating bonded composite products composed of a plurality of materials with a low affinity for mutual bonding, comprising the steps of:
- extruding a first stream of a first plastic through a die to form a profile, coextruding a second stream of plastic through said die which is fusible with said first stream as a surface layer on said profile, said second stream being blended with an additive capable of interrupting the homogeneous structure of said plastic;
- allowing said surface layer to rupture upon emergence from the die, as a result of pressure drop and shear stresses due to friction at the surface of the die, so as to form a rough surface comprising a pattern of irregular projections and cavities;
- applying a flowable coating of a second plastic material, with a low bonding affinity for said first plastic, on to said rough surface to surround said projections and invade said cavities;
- hardening said coating material.
Dependencies are inferred from the claim text.