Canadian Plastics

The Tpe Top Ten List

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 ...

June 1, 1999   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 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.


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