Polylactic acid shrink films and methods of casting same
AssigneePlastic Suppliers, Inc.
InventorsEdward Carl Tweed, Joseph B. McDaniel
Life of this patent
Estimating the term…
Abstract
A heat-shrinkable polylactic acid (PLA) film and a method of its manufacture are provided. In an exemplary embodiment, the PLA films exhibit heat-induced shrinkage in the transverse direction with little to no concomitant shrinkage in the machine direction. The films may comprise any grade of PLA polymer, optionally including additives, such as antiblock, slip, plasticizers, viscosity enhancers and combinations thereof. A method of cast and tenner manufacture is disclosed, which includes a temperature conditioning step.
Claims28
A shrink film comprising a polylactic acid (PLA) polymer blend which, upon exposure to 60° C. heat for about 10 seconds, exhibits shrinkage in the transverse direction in the range of about 10% to about 80% and shrinkage the machine direction that does not exceed about 10%.
A packaged good comprising a consumable item and a heat treated PLA shrink sleeve over at least a portion of the consumable item, which heat treated sleeve is obtained by exposing to heat a shrink film comprising a PLA polymer blend film which, upon exposure to heat, exhibits shrinkage in the transverse direction in the range of about 10% to about 80% and shrinkage the machine direction that does not exceed about 10%.
A method of casting a PLA shrink film which, upon exposure to heat, exhibits shrinkage in the transverse direction in the range of about 10% to about 80% and shrinkage the machine direction that does not exceed about 10%, comprising (a) providing dry pellets of PLA, (b) melting the pellets to form a molten mass, (c) extruding the resulting molten mass, (d) casting the extrusion between three or more casting rollers to form a film, (e) temperature conditioning the film, and (f) stretching the film in the transverse direction.
Dependencies are inferred from the claim text.