Maximizing Adhesion in Over-Molding
Having problems with achieving good adhesion in your over-molding application? Let Entec Polymers help with their proven suggestions for achieving maximum adhesion of the over-mold material onto the substrate material.
- Two-shot co-injection molding is preferred over insert-molding
- Use the correct type of TPE for a given substrate
- Ensure adequate thickness of TPE over-mold (thicker is better)
- Ensure that TPE material is dry (substrate material too)
- Use melt temperature on the high side of the range
- Use mold temperature on the high side of the range
- Injection speed should be as fast as possible
- Vent the mold as much as possible
- Texture substrate material if possible
- Ensure substrate material is clean (if insert molding)
- Pre-heat substrate material (if insert molding)
- Flame or corona treat substrate material (if insert molding)
- Use mechanical interlocks for additional over-mold adhesion
- Use good shut-offs (do NOT feather / thin)
- Ensure resin rich surface if substrate material is reinforced
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