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

A compression molding process for encapsulating an electrically functional device with at least one layer of a thermoplastic sheet material prepared via a wet lay process, said thermoplastic sheet material comprising a thermoplastic polymeric material selected from the group consisting of polyesters, polyamides, acrylics, copolyetheresters, polyolefins and mixtures thereof and 10-50 weight percent of a glass fiber material;

• said compression molding process comprising the steps of
• (a) placing the electrically functional device in the bottom of a compression molding die assembly cavity, equipped with a mold and an upper punch, such that one part of the electrically functional device is exposed for encapsulation and the remaining part of the electrically functional device is protected from encapsulation by one or more isolation inserts,
• (b) heating the thermoplastic sheet material to a temperature above the melting point of the thermoplastic polymeric material and arranging the heated thermoplastic sheet material over the part of the electrically functional device to be encapsulated,
• (c) heating the mold to slightly above the melt temperature of the thermoplastic polymeric material,
• (d) closing the mold cavity by lowering the punch completely into the cavity and the mold,
• (e) applying 500-3,000 pounds per square inch of pressure to the mold while lowering the molding temperature to below the melting point of the thermoplastic polymeric material, at which time, pressure is reduced to 0 pounds per square inch,
• (f) repeating the process of steps (a)-(e) for the parts of the electrically functional device that are not encapsulated until the entire electrically functional device is encapsulated, 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.

A compression molding process for encapsulating an electrically functional device with at least two layers of a thermoplastic sheet prepared via a wet lay process, said thermoplastic sheet comprising a thermoplastic polymeric material selected from the group consisting of polyesters, polyamides, acrylics, copolyetheresters, polyolefins and mixtures thereof and 10-50 weight percent of a glass fiber material;

• said compression molding process comprising the steps of
• (a) heating at least two thermoplastic sheets or preforms thereof to a temperature above the melting point of the thermoplastic polymeric material;
• (b) heating a first mold segment and a second mold segment to a temperature just above the melting point of the thermoplastic polymeric material in the thermoplastic sheets or preforms, said first and second mold segments being positioned opposite each other in a press;
• (c) placing at least one, but not all, of the heated thermoplastic sheets or preforms in said heated first mold segment;
• (d) placing the electrically functional device adjacent to the at least one heated thermoplastic sheet or preform in the heated first mold segment such that said at least one heated thermoplastic sheet or preform lay between said heated first mold segment and said electrically functional device;
• (e) placing at least one other heated thermoplastic sheet or preform between the electrically functional device and the heated second mold segment such that the electrically functional device is positioned between said at least two heated thermoplastic sheets or preforms;
• (f) closing said first and second mold segments together until said mold segments are mated;
• (g) applying 500-3,000 pounds per square inch of pressure to the mold while lowering the mold temperature to below the melting point of the thermoplastic polymeric material, at which time the pressure is reduced to 0 pounds per square inch;
• and
• (h) separating said first and second mold segments and removing an encapsulated electrically functional device from the mold.