Rapid film formation
CAB can be used as a film former, as a reactive polyol in curing coatings, and as an additive to other film formers.
The reactive hydroxyl groups contained in CABs may be cross-linked with urea-formaldehyde, melamine, or polyisocyanate resins. They provide the ability to formulate a variety of curing coatings and inks. Selecting higher-hydroxyl cellulose esters such as Eastman CAB 553-0.4 for use in curing systems produces films with high cross-link density and excellent chemical and physical properties.
Due to its high glass transition temperature (Tg), CAB provides excellent hardness and hardness development.
As an example, the addition of 15%–30% CAB (based on resin solids) in thermosetting acrylic enamels provides a coating that dries like a lacquer on a hard surface and can be sanded to remove orange peel, sags, or embedded dirt. Spot repairs can then be made with the original coating composition. During the final bake at converting temperature, the enamel reflows to eliminate sand marks and provides a glossy thermoset finish.