Gas-assisted two-shot injection molding process

摘要

A process for injection molding a composite of rigid thermoplastic and soft thermoplastic, the soft thermoplastic including a cavity established with pressurized assist gas or an assist liquid. The process includes the steps of: injecting a hard molten thermoplastic into a first mold chamber; injecting a soft molten thermoplastic into a second mold chamber; establishing communication between the first chamber and the second chamber so that the rigid thermoplastic and soft thermoplastic integrally bond; and injecting an assist fluid into the soft thermoplastic to form a cavity. In a preferred embodiment, the formed composite is an automotive cowl where the rigid thermoplastic forms the rigid body portion of the cowl and the integrally bonded soft thermoplastic forms a compressible bulb seal.