Bio based biodegradable polymer compositions and use of same

1 . A biodegradable polymer composition useful for manufacturing biodegradable items or articles with improved mechanical properties comprising poly(lactic acid) polymer (PLA), starch and protein material, obtainable by

i) providing poly(lactic acid) polymer (PLA), starch and protein material in such ratios that PLA/starch blend represents at least 95% weight of the above three components and that starch represents at least 23% weight of PLA;

ii) mixing the above three components at room temperature in a controlled moisture atmosphere to afford a homogeneous mixture;

iii) subjecting the above homogeneous mixture to extrusion compounding under controlled heat, speed and pressure conditions; and

iv) drying down to a maximum of approximately 1% weight of moisture and subsequently conditioning the extruded polymeric composition.

2 . The biodegradable polymeric composition according to claim 1 wherein the protein material is gluten and wherein it represents from 1 to 5% weight of the PLA/starch blend.

3 . The biodegradable polymeric composition according to claim 1 wherein starch is either native or thermoplastic starch and wherein it represents from 15 to 55% weight of the PLA/starch blend.

4 . The biodegradable polymeric composition according to claim 3 wherein starch represents from 25 to 45% weight of the PLA/starch blend.

5 . The biodegradable polymer composition according to claim 1 wherein PLA, starch and the protein material are further mixed with additional components selected from the group consisting of a polymerization initiator and an inert material.

6 . The biodegradable polymer composition according to claim 1 wherein the components provided in step i) are dried down to a maximum of approximately 1% weight of moisture prior mixing.

7 . The biodegradable polymer composition according to claim 1 wherein the components subjected to blending and subsequent extrusion compounding are dried down to a maximum of approximately 1 weight % of moisture prior to conditioning.

8 . The biodegradable polymer composition according to claim 1 wherein extrusion compounding is multiple screw extrusion performed at a temperature of about 95° C. to about 190° C. for a period of about 1 to about 10 minutes.

9 . A process for manufacturing substantially or totally bio based biodegradable items or articles with improved mechanical properties which comprises subjecting a biodegradable polymer composition useful for manufacturing biodegradable items or articles with improved mechanical properties comprising poly(lactic acid) polymer (PLA), starch and protein material, obtainable by

i) providing poly(lactic acid) polymer (PLA), starch and protein material in such ratios that PLA/starch blend represents at least 95% weight of the above three components and that starch represents at least 23% weight of PLA;

ii) mixing the above three components at room temperature in a controlled moisture atmosphere to afford a homogeneous mixture;

iii) subjecting the above homogeneous mixture to extrusion compounding under controlled heat, speed and pressure conditions; and

iv) drying down to a maximum of approximately 1% weight of moisture and subsequently conditioning the extruded polymeric composition to an operation selected from the group of forming, molding, injection, molding, extrusion coating and thermoform extrusion.

10 . A substantially or totally bio based biodegradable item or article with improved mechanical properties obtainable by means of the process according to claim 9 .

11 . An item or an article according to claim 10 which is designed to be totally degraded in a natural environment, preferably in a time period that is significantly shorter than that required for the degradation of conventional polymer or plastic materials.

12 . An item or an article according to claim 10 which is designed to be in contact with food material or food products.

13 . An item or an article according to claim 10 which is selected from the group consisting of utensils, food service-ware, forks, spoon, knives, chopsticks, containers, bottles, foam material products, plates and pots or films, trash bags, grocery bags, container sealing films, pipes, drinking straws, spun-bonded non-woven material and sheets.

14 . A process for preparing a biodegradable polymer composition useful for manufacturing bio based biodegradable items or articles, which comprises

i) providing poly(lactic acid) polymer (PLA), starch and protein material in such ratios that PLA/starch blend represents at least 95% weight of the above three components and that starch represents at least 23% weight of PLA;

ii) mixing the above three components at room temperature in a controlled moisture atmosphere to afford a homogeneous mixture;

iii) subjecting the above homogeneous mixture to extrusion compounding under controlled heat, speed and pressure conditions; and

iv) drying down to a maximum of approximately 1% weight of moisture and subsequently conditioning the extruded polymeric composition.

15 . A process for improving processability of biodegradable polymers based on poly(lactic acid) polymer (PLA), starch and protein material, which comprises

i) providing poly(lactic acid) polymer (PLA), starch and protein material in such ratios that PLA/starch blend represents at least 95% weight of the above three components and that starch represents at least 23% weight of PLA;

ii) mixing the above three components at room temperature in a controlled moisture atmosphere to afford a homogeneous mixture;

iii) subjecting the above homogeneous mixture to extrusion compounding under controlled heat, speed and pressure conditions; and

iv) drying down to a maximum of approximately 1% weight of moisture and subsequently conditioning the extruded polymeric composition.