DRYING CHARACTERISTICS AND RHEOLOGY OF CARBOXYMETHYLCELLULOSE ACETATE BUTYRATE IN WATERBORNE COATINGS

摘要

Water dispersible carboxymethylcellulose acetate butyrate (CMCAB cellulose ester) is the latest generation of mixed cellulose esters that has shown reduced dry to touch times, improved metallic flake orientation in metallic base coats, and improved flow and leveling characteristics. These improved properties are achieved through a combination of near-Newtonian rheology, a fast increase in viscosity during drying, and high Tg of CMCAB cellulose ester. A novel dynamic mechanical test was used to monitor the change in the viscoelastic properties of thin-film coatings based on CMCAB cellulose ester during drying. The unique drying characteristics and other rheological aspects of waterborne systems containing CMCAB cellulose ester during early film formation will be discussed.