PREPARATION OF POLY ALPHA-1,3-GLUCAN ESTER FILMS
The present disclosure is directed toward an extrusion process for making a poly alpha-1,3-glucan ester film. These films can be translucent and used in packaging applications.
1 . A process for making a poly alpha-1,3-glucan ester film comprising:
(a) dissolving poly alpha-1,3-glucan ester in a solvent composition to provide a solution of poly alpha-1,3-glucan ester;
(b) extruding the solution of poly alpha-1,3-glucan ester into a coagulation bath to make a film-shaped wet gel;
(c) washing the film-shaped wet gel with a wash liquid;
(d) optionally, plasticizing the film-shaped wet gel with a plasticizer additive; and
(e) removing the wash liquid from the film-shaped wet gel to form a poly alpha-1,3-glucan ester film. 15
2 . The process according to claim 1 , where the poly alpha-1,3-glucan ester is poly alpha-1,3-glucan acetate.
3 . The process according to claim 1 , wherein the solvent composition further comprises a solubility additive, a plasticizer additive or a mixture thereof.
4 . The process according to claim 1 , where the solvent composition comprises formic acid.
5 . The process according to claim 1 , wherein the coagulation bath comprises a water bath.
6 . The process according to claim 1 , wherein the wash liquid comprises water.
7 . The process according to claim 1 , wherein the film-shaped wet gel has a breaking stress of at least about 1.5 MPa.
8 . A poly alpha-1,3-glucan ester film made according to claim 1 .
9 . A film comprising poly alpha-1,3-glucan ester.
10 . The film according to claim 9 , wherein the film has at least one of:
(a) haze less than about 10%; or
(b) breaking stress from about 10 to about 100 MPa.