Water-dispersible carboxymethylcellulose acetate butyrate (CMCAB[TM]) cellulose ester is the latest generation of mixed cellulose esters developed for use in aqueous coating formulations. In waterborne coatings, it offers reduced dry-to-touch times, improved metallic flake orientation in metallic basecoats, and improved flow and leveling characteristics. Like CAB in solventborne systems, CMCAB achieves these effects through near-Newtonian rheology, high Tg, and a steep viscosity/solids relationship.
Cellulose ester technology has been used in coatings since 1890 when cellulose nitrate (NC) was found to be useful as a coatings resin. Cellulose acetate (CA) and mixed cellulose esters such as cellulose acetate butyrate (CAB) and cellulose acetate propionate (CAP) were developed in the 1930s as a less flammable alternative to nitrate-based coatings for military aircraft. Cellulose esters can be used as binder resins or as additives to coatings to provide application properties and resist film defects.