ASTM D4817-88(2005)

1.1 This classification covers the compounding materials commercially known as stearic acid.

1.2 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.

Stearic acid is important in the rubber vulcanization process. It is believed that the stearic acid reacts with zinc-oxide or other metallic oxides, during vulcanization, to form a rubber soluble salt or soap, that reacts with the accelerator enabling it to exert its full effect.

Stearic acid of commerce is generally a mixture of palmitic, stearic, and oleic acids usually derived from tallow base stock but can be derived from other fats and oils of animal or vegetable origins.