Hardness Test Method Change Question

Hardness Test Method Change Question

A customer called in today asking why the hardness has changed on the Santoprene™ brand TPVs. He noted as an example, 101-73 used to be listed as a 73 Shore A durometer, as represented by the product nomenclature, but is now listed as 78 Shore A on the product datasheet. I responded that the durometer and the product have not changed, but simply, the test method used to determine the durometer has changed to be more representable globally. According to ASTM D2240 test method, the method which was previously used, the durometer should still be 73 Shore A. The test method currently used, ISO 868, records a higher result of 78 Shore A. This is due to a difference in test methods, mainly due to the Shore hardness lever loader, the tip use, the force used and the delay time.

Posted on 2008-04-17 1:10 PM