Biodegradable polymer films and sheets suitable for use as laminate coatings as well as wraps and other packaging materials

Abstract

Biodegradable polymer blends suitable for laminate coatings, wraps and other packaging materials 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 and thermoplastically processable starch. 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 so as to have good “dead-fold” properties so as to remain in a wrapped position and not spring back to an “unwrapped” and planar form. Laminate films will typically have good water vapor barrier properties as measured by the their Water Vapor Permeability Coefficient (WVPC).