A METHOD OF FORMING A LIGHT-WEIGHT, FIBER-REINFORCED THERMOPLASTIC RESIN PRODUCT AND A LIGHT-WEIGHT MOLDED PRODUCT

摘要

The method of forming a light-weight, fiber-reinforced, particularly glass fiber-reinforced-thermoplastic resin product includes the steps of melting and mixing thermoplastic resin pellets containing parallely oriented fibers 2-100 mm long, injecting the melted resin into a cavity which is closed so that its volume is smaller than that of the final molded product, and, before or after the resin injection is completed, opening the cavity until its volume is equal to that of the final molded product. Unlike the conventional injection-molded products, this product does not require a foaming agent and, if it uses any, requires only a small amount of foaming agent. The product thus formed is light in weight and has fibers uniformly entangled inside, providing an excellent appearance of the surface. Further a skin layer is formed over the surface. These features combined with the reinforcement by the glass fibers offer high strength and high stiffness.