Cellulose propionate, commonly called “CP”or propionate, is made by the same generalmethod as cellulose acetate, but propionic acidis used in the reaction. Propionate offers severaladvantages over cellulose acetate for manyapplications. Because it is “internally” plasticizedby the longer-chain propionate radical, itrequires less plasticizer than is required for celluloseacetate of equivalent toughness.
Cellulose propionate absorbs much less moisturefrom the air and is thus more dimensionallystable than cellulose acetate. Because of betterdimensional stability, cellulose propionate is oftenselected where metal inserts and close tolerancesare specified.
Largest-volume uses for cellulose propionateare as industrial parts (automotive steeringwheels, armrests, and knobs, etc.), telephones,toys, findings, ladies’ shoe heels, penand pencil barrels, and toothbrushes.
