Overmold (Adhesive TPE Compound)

Overmolding is a molding method where two different materials are laminated together by injection molding. Overmolding elastomer compounds require strong adhesion to the substrate, suppression of transparency reduction in the molded product, and flowability that prevents uneven appearance.

Asahi Kasei's TUFTEC™ and S.O.E.™ can be incorporated into the compound as additives to meet these requirements, achieving overmolding with desired properties.

In the overmolding process, insufficient adhesion between the substrate and the compound can lead to delamination of the overmolded portion (such as tool grips) when subjected to force. Therefore, high adhesion between the overmolding compound and the substrate is crucial.

TUFTEC™ H1517 and S.O.E.™ S1614 achieve excellent heat fusion and adhesion to highly polar substrates such as PC (polycarbonate) and ABS resin.

In some product designs, transparent overmolding is required. In such cases, using elastomer compounds containing polypropylene (PP) can lead to reduced transparency in the molded product.

Asahi Kasei's TUFTEC™ H1517 and other grades with good compatibility with PP, when used as additives, enable the production of transparent molded products even when PP is incorporated. Furthermore, TUFTEC™ offers the advantage of high adhesion to the substrate.

Low flowability of overmolding compounds can result in short shots and flow marks depending on the substrate shape.

S.O.E.™ S1614, with its high flowability, is an effective solution to such problems. By incorporating S1614 into the compound, a compound with excellent injection moldability and processability is obtained. This effectively suppresses the occurrence of short shots and flow marks.