Cellulose Acetate Propionate (CAP) belongs to a group of cellulose based specialty polymers that have been used in the printing industry for decades. The other members of the family include cellulose acetate (CA) and cellulose acetate Butyrate (CAB) and these are all manufactured by the Eastman Chemical company.
This article focuses on some of the uses of CAP for flexographic and gravure inks as this particular group of polymers offers good compatibility, a wide range of solubility parameters and is particularly useful in the manufacture of inks for food packaging due to their low odor and excellent solvent release characteristics. Additionally, propionate esters are particularly useful because they are very stable (even with dyes and metallic pigments) and are suitable for dispersing a wide range of pigments.