Biodegradable polyester article comprising enzymes

Abstract

The present invention relates to novel biodegradable plastic articles comprising a polyester and biological entities able to degrade such polyester, and wherein the biological entities are homogeneously dispersed in the plastic articles. The invention also relates to a process for producing such plastic articles, comprising a step of mixing biological entities with a selected carrier in a liquid composition or in a masterbatch with the polyester.

1 .- 45 . (canceled) 
     
     
         46 . A biodegradable plastic article comprising at least one polyester and enzymes having a polyester-degrading activity, comprising a polysaccharide carrier selected from starch derivatives, natural gums, marine extracts, microbial and animal polysaccharides and mixtures thereof and optionally a carrier polymer having a melting temperature below 140° C. and/or a glass transition temperature below 70° C., the biological entities being able to degrade said polyester and being homogeneously dispersed in the plastic article. 
     
     
         47 . The plastic article of  claim 46 , wherein the polyester has a melting temperature above 140° C. 
     
     
         48 . The plastic article of  claim 46 , wherein the starch derivative is maltodextrin. 
     
     
         49 . The plastic article of  claim 46 , wherein the natural gum is selected from arabic gum, guar gum, tragacanth gum, karaya gum and mixtures thereof. 
     
     
         50 . The plastic article of  claim 46 , comprising a carrier polymer having a melting temperature below 140° C. and/or a glass transition temperature below 70° C. selected from a polyester, starch, EVA and mixtures thereof. 
     
     
         51 . The plastic article of  claim 50 , wherein the carrier polymer having a melting temperature below 140° C. and/or a glass transition temperature below 70° C. is a polyester selected from polycaprolactone (PCL), polybutylene succinate adipate (PBSA), polybutylene adipate terephthalate (PBAT), polydioxanone (PDS), polyhdroxyalkanoate (PHA), polylactic acid (PLA) and mixtures thereof. 
     
     
         52 . The plastic article of  claim 46 , wherein the enzymes represent less than 11% by weight of the total weight of the plastic article. 
     
     
         53 . The plastic article of  claim 46 , comprising, based on the total weigh of the plastic article:
 between 10 to 98% of polylactic acid (PLA);   between 0.01 to 10% of a polysaccharide carrier;   between 0 to 30% of a carrier polymer having a melting temperature below 140° C. and/or a glass transition temperature below 70° C.; and   between 0.01 to 10% of enzymes having a PLA-degrading activity.   
     
     
         54 . The plastic article of  claim 46 , comprising at least 3% of a carrier polymer having a melting temperature below 140° C. and/or a glass transition temperature below 70° C. 
     
     
         55 . The plastic article of  claim 46 , comprising between 0.1% to 1% of polysaccharide carrier. 
     
     
         56 . The plastic article of  claim 46 , being a plastic film with a thickness below 250 μm. 
     
     
         57 . The plastic article of  claim 46 , being a rigid article. 
     
     
         58 . A process for preparing a plastic article comprising at least one polyester and enzymes having a polyester-degrading activity homogeneously dispersed in the plastic article, said process comprising a step (a) of mixing between 0.01% and 10% by weight of enzymes having a polyester-degrading activity with a least said one polyester and a step (b) of shaping said mixture of step (a) in a plastic article,
 wherein the enzymes are mixed during step (a) under a form appropriate for allowing homogeneous dispersion of the said enzymes in the plastic article, selected from:
 a liquid composition comprising the enzymes, a polysaccharide carrier and water, or 
 a masterbatch comprising the enzymes and a carrier polymer having a melting temperature below 140° C. and/or a glass transition temperature below 70° C., 
   wherein said masterbatch is prepared by mixing a liquid composition of the enzymes with the carrier polymer in a partially or totally molten state.   
     
     
         59 . The process according to  claim 58 , wherein the step (a) of mixing is performed at a temperature at which the polyester is in a partially or totally molten state and/or in an extruder. 
     
     
         60 . The process of  claim 58 , wherein the polyester has a melting temperature above 140° C. 
     
     
         61 . The process of  claim 58 , wherein the polysaccharide carrier is selected from starch derivatives, natural gums, marine extracts, microbial and animal polysaccharides and mixtures thereof. 
     
     
         62 . The process of  claim 58 , wherein the carrier polymer having a melting temperature below 140° C. and/or a glass transition temperature below 70° C. is a polyester selected from polycaprolactone (PCL), poly butylene succinate adipate (PBSA), polybutylene adipate terephthalate (PBAT), polydioxanone (PDS), polyhdroxyalkanoate (PHA), polylactic acid (PLA) and mixtures thereof. 
     
     
         63 . A plastic composition under a granulated form, comprising a polyester and said polyester degrading biological entities and produced from a process as defined in  claim 58 . 
     
     
         64 . A masterbatch comprising enzymes having a polyester-degrading activity, a polysaccharides carrier and a carrier polymer having a melting temperature below 140° C. and/or a glass transition temperature below 70° C., wherein said masterbatch is prepared by mixing a liquid composition of the enzymes with the carrier polymer in a partially or totally molten state. 
     
     
         65 . The masterbatch of  claim 64 , wherein the polymer having a melting temperature below 140° C. and/or a glass transition temperature below 70° C. is a polyester selected from polycaprolactone (PCL), polybutylene succinate adipate (PBSA), polybutylene adipate terephthalate (PBAT), polydioxanone (PDS), polyhdroxyalkanoate (PHA), polylactic acid (PLA) and mixtures thereof. 
     
     
         66 . The masterbatch of  claim 64 , comprising between 50% and 95% by weight of carrier polymer having a melting temperature below 140° C. and/or a glass transition temperature below 70° C. based on the total weight of the masterbatch. 
     
     
         67 . The masterbatch of  claim 64 , comprising between 5% to 50% by weight of enzymes based on the total weight of the masterbatch. 
     
     
         68 . The masterbatch of  claim 64 , wherein the polysaccharide carrier is selected from starch derivatives, natural gums, marine extracts, microbial and animal polysaccharides and mixtures thereof. 
     
     
         69 . The masterbatch of  claim 64 , comprising between 1% to 30% of polysaccharide carrier. 
     
     
         70 . The process of  claim 58 , wherein the masterbatch is prepared by mixing a liquid composition comprising the enzymes and the polysaccharide carrier with the carrier polymer at a temperature at which the carrier polymer is in a partially or totally molten state.