Toughened polyester blends

摘要

The properties of melt blends of specific aliphatic-aromatic copolyesters and starch are improved by addition of a combination of polylactic acid, graft copolymers such maleic anhydride grafted polyethylene and maleic anhydride grafted polystyrene, and a hindered phenolic antioxidant. The blends exhibit increased melt strength and maximum draw down ratio versus blends of only aliphatic-aromatic copolyesters and starch. Films made from the blend are compostable and exhibit an attractive combination of mechanical and rheological properties for packaging materials.

主权项

1. A composition comprising a melt blend of
(a) 50 to 70 wt % copolyester made from monomers comprising 1,3-propanediol, terephthalic acid, and a linear aliphatic dicarboxylic acid, wherein the molar ratio of terephthalic acid to linear aliphatic acid is between 75:25 and 80:20; (b) 15 to 50 wt % starch; (c) 6 to 13 wt % polylactic acid; (d) 0.5 to 5.0 wt % graft copolymer of a polyolefin or a polystyrene; and (e) optionally 0.5 to 5.0 wt % hindered phenol antioxidant.