Shellac dispersions and coatings, and method of making

摘要

A method of forming the aqueous-based shellac dispersion includes dissolving a shellac solution in a basic aqueous solvent to form a shellac solution and subsequently combining the shellac solution with an acidic aqueous solution, whereby the shellac precipitates to form the aqueous-based shellac dispersion. A film can be formed by applying the shellac dispersion to a suitable surface and exposing the dispersion to conditions which cause a substantial portion of the shellac particles in the dispersion to fuse, thereby forming a shellac film on the surface. The shellac film does not include any organic solvent for the shellac or any amine-containing shellac salt. A plasticizer can be employed to form a continuous shellac coating on a substrate at significantly reduced temperatures.