Process for encapsulating inserts with wet-laid material via compression molding

摘要

A compression molding process for encapsulating a metal-containing insert with at least one layer of a thermoplastic sheet prepared via a wet lay process. The thermoplastic sheet material contains a thermoplastic polymeric material and a glass fiber material, and the compression molding process includes the steps of (a) heating the thermoplastic sheet material to a temperature above the melting point of the thermoplastic polymeric material; (b) placing the heated thermoplastic sheet material into the bottom of a mold on a compression molding die assembly, the mold having been heated to a temperature just above the melting point of the thermoplastic polymeric material; (c) fastening the metal-containing insert to an unheated upper punch of the compression molding die assembly, such that a part of the metal-containing insert is exposed for encapsulation; (d) lowering the upper punch into the mold of the compression molding die assembly until the metal-containing insert is forced into the heated thermoplastic sheet material; (e) applying 500-3,000 pounds per square inch of pressure to the old while lowering the old temperature to below the melting point of the thermoplastic polymeric material, at which time the pressure is reduced to 0 pounds per square inch; (f) repeating the process of steps (a)-(e) for the unencapsulated parts of the metal-containing insert until the entire metal-containing insert is encapsulated with the thermoplastic sheet material; and (g) optionally sealing any parting line resulting from the compression molding process by caulking with an elastomeric material, welding by ultrasound, or heating by induction.