Patent ID: 7294302

Claim:
A method for controlling a thickness of a skin layer on a composite product having the skin layer and a core layer, comprising steps of: (a) adding a carbon nanomaterial to at least one of a first thermoplastic resin and a second thermoplastic resin, to cause or increase a difference in viscosity between those resins; (b) injection molding the first thermoplastic resin into a mold through a gate or hot runner using a first injection machine; and (c) injection molding the second thermoplastic resin into the mold through said gate or hot runner using a second injection machine, wherein said second thermoplastic resin is injected into said first thermoplastic resin so that the skin layer of said composite product contains said first thermoplastic resin and the core layer contains said second thermoplastic resin, and wherein the thickness of the skin layer is controlled by said difference in viscosity.