Message: | Waxes (both natural and petroleum derived) have long been used as process aids
in rubber. They provide economical internal lubrication, mill and mold release,
and improved compound flow. It was probably a fortuitous insight that connected
compounds containing petroleum wax with less surface cracking of rubber parts
exposed to an outdoor environment. It was believed that the cracking was caused by
sunlight exposure, so the name "antisunchecking" wax was used. This is a misnomer.
While the sun (via ultraviolet degradation) can cause crazing or "alligator skin" in
rubber, wax provides little or no resistance to sunlight (or UV) deterioration. Petroleum
waxes do provide protection against ozone attack of rubber parts. It’s important to
know the difference between ozone and UV degradation if parts come back from the
field with surface cracking. url:http://www.rubberplasticparts.com |