Biodegradable polymer blends for use in making films, sheets and other articles of manufacture

Abstract

Biodegradable polymer blends suitable for laminate coatings, wraps and other packaging materials are manufactured from at least one 'hard' biopolymer and at least one 'soft' biopolymer. “Hard” biopolymers tend to be more brittle and rigid and typically have a glass transition temperature greater than about 10° C. “Soft” biopolymers tend to be more flexible and pliable and typically have a glass transition temperature less than about 0° C. While hard and soft polymers each possess certain intrinsic benefits, certain blends of hard and soft polymers have been discovered which possess synergistic properties superior to those of either hard or soft polymers by themselves. Biodegradable polymers include polyesters, polyesteramides, polyesterurethanes, thermoplastic starch, and other natural polymers. The polymer blends may optionally include an inorganic filler. Films and sheets made from the polymer blends may be textured so as to increase the bulk hand feel. Wraps will typically be manufactured to have good “dead-fold” properties so as to remain in a wrapped position and not spring back to an “unwrapped” form.