The Tpe Top Ten List
Canadian Plastics
Injection molders contemplating TPE processing but not knowing where to start should take a look at the following "Top Ten" list from Advanced Elastomer Systems. Although the list refers specifically ...
Injection molders contemplating TPE processing but not knowing where to start should take a look at the following “Top Ten” list from Advanced Elastomer Systems. Although the list refers specifically to AES’s flagship Santoprene products, the recommendations show where TPE’s depart from conventional thermoplastics practice:
1. DO NOT use PVC or acetal before or after running TPE’s. This is a safety issue.
2. Cooling time is dependent on wall thickness, grade, and tool design.
3. Cushion size is typically 0.125″ to 0.25″.
4Hold time is typically three to four seconds and hold pressure is approximately 50 percent of
injection pressure.
5 It’s far more effective to increase shear rate than to raise melt temperature for filling a mold.
6. Injection rate should be 10 to 50 g/sec/gate.
7. Injection speed should be medium (50%) to maximum (100%) of machine capacity.
8. Injection times range from 0.5 to 2.5 seconds to optimize shear in the material.
9. Where regrind can be used (as with Santoprene products), use consistent regrind ratios to minimize
process variations.
10. Pre-drying is recommended: three hours at 82C (180F) for virgin material, and four hours at
82 C (180 F) for regrind material.
