Biodegradable sheets

Abstract

The present invention relates to a biodegradable sheet comprising at least two polymer layers, wherein a first polymer layer comprises a mixture of at least two different biodegradable polymers selected from the group consisting of PLA, PCL, PBS and PBSA; and wherein a second polymer layer comprises a biodegradable polymer selected from the group consisting of PBS, PBSA, a mixture of PLA and PBS, and a mixture of PLA and PBSA.

1 . A biodegradable sheet comprising at least three polymer layers,
 wherein at least one of a first polymer layer and a second polymer layer comprises PBS or PBSA;   wherein a third polymer layer comprises PLA and PCL;   and wherein said third polymer layer is positioned between said first polymer layer and said second polymer layer.   
     
     
         2 . The biodegradable sheet according to  claim 1 , wherein said third polymer layer comprises PLA at a concentration of from about 50 to about 70% (w/w) of said mixture and PCL at a concentration of from about 30 to about 50% (w/w) of said mixture. 
     
     
         3 . The biodegradable sheet according to  claim 1 , wherein said third polymer layer comprises PLA at a concentration of from about 60 to about 70% (w/w) of said mixture and PCL at a concentration of from about 30 to about 40% (w/w) of said mixture. 
     
     
         4 . The biodegradable sheet according to  claim 1 , wherein said first polymer layer and said second polymer layer each comprise 100% PBS. 20 
     
     
         5 . The biodegradable sheet according to  claim 1 , wherein said first polymer layer and said second polymer layer each comprise 100% PBSA. 
     
     
         6 . The biodegradable sheet according to  claim 1 , further comprising at least one coating layer on one or both surfaces of at least one layer of said three polymer layers. 
     
     
         7 . The biodegradable sheet according to  claim 6 , wherein said at least one coating layer comprises a coating selected from the group consisting of shellac, cellulose and copolymer of vinylidene chloride (PVDC). 
     
     
         8 . The biodegradable sheet according to  claim 6 , further comprising a metal coating layer. 
     
     
         9 . The biodegradable sheet according to  claim 7 , wherein said coating layer comprises PVDC. 
     
     
         10 . The biodegradable sheet according to  claim 1 , prepared by co-extrusion of three polymer layers.