ABSTRACT

Predicting the suitability or life of any material for a particular application or environment is difficult without extensive field tests that duplicate the proposed environment. This is especially true for adhesive systems because the adhesive is only half of the system. At aging temperature, most machinery adhesives will crosslink more than occurred during the preliminary lower-temperature cure. The liquid machinery adhesive may have a surface effect on steel and copper when the relative humidity is greater than 50% and contact is maintained without cure for 24 hours or more. With machinery adhesives, hot strength determination is more a tradition than a requirement because they are highly crosslinked and therefore behave as thermoset rather than thermoplastic materials. Machinery adhesives are somewhat more complicated than plastics to test because they are always tied to a substrate and cure may not be entirely complete when the degradation test is started.