Northern Technologies International Corporation

Matthew Lundblad

Shilpa Manjure

Nagaraj Kuppusamy

The invention relates to a biodegradable and compostable blend of polylactic acid, a compostable polyester with or without carbon based biocontent, polyethylene glycol, and optionally an inorganic talc filler that have greatly increased elongation, flexibility, and tensile toughness as measured by tensile test ASTM D638-10. These blends of PLA with 5-30% of said polyester, about 10% PEG, and about 5% of an inorganic talc filler unexpectedly increased the elongation to 750+ % for molded test bars. Additionally, 4 mil films showed a max tear strength of about 1200 gms (in MD) and 900 gms (in TD) measured by ASTM D1922-09 while maintaining other preferable properties.

Biobased polyester blends with enhanced performance properties

Polylactide (PLA) parts can be crystallized via two procedures. In the first procedure, i.e. a 2-step post-mold annealing process, the complete crystallization of PLA parts can be done after molding in a secondary operation called as post-mold annealing to make higher heat-resistant PLA parts. There are limitations to this 2-step operation, namely, a) warpage of parts with complex geometries, and b) scaling up higher production volume times. In the second procedure, i.e. 1-step in-mold annealing process, the complete crystallization of PLA parts can be done in the mold itself by holding the temperature of the mold at the crystallization temperature of PLA which is about 100° C. The 1-step in-mold annealing process using a masterbatch blended with neat PLA results in a highly crystalline article produced in a significantly lower cycle time.

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Woodbury, MN, United States of America

Matthew Lundblad