Patent ID: 7744806

Claim:
A process for making a heat-shrinkable annular film, comprising: (A) extruding an annular multilayer extrudate downward from an annular die, the annular multilayer extrudate comprising: (i) a first layer which is an outer seal layer, the first layer comprising at least one member selected from the group consisting of a polyolefin having a density of from 0.88 g/cm 3 to 0.917 g/cm 3 , and ionomer resin, and (ii) a second layer comprising at least one semi-crystalline polyamide selected from the group consisting of polyamide 6, polyamide 66, polyamide 6/66, and polyamide 6/12, and with the annular multilayer extrudate comprising at least one member selected from the group consisting of polyamide 6, polyamide 66, polyamide 6/66, and polyamide 6/12 in an amount of at least 30 volume percent, based on total film volume; (B) quenching the annular extrudate by applying a quenching liquid to the annular extrudate, with the quenching liquid absorbing heat from the annular extrudate as at least 50% of the quenching liquid cascades down the annular extrudate for a distance of at least 2 inches, the quenching liquid making initial contact with the annular extrudate at a distance of from 0.1 to 8 inches downstream of a point at which the annular extrudate emerges from the annular die; (C) reheating the extrudate to an orientation temperature of from 130° F. to 210° F., resulting in a reheated annular extrudate; (D) orienting the reheated annular extrudate while the reheated annular extrudate is in the solid state, the orientation being carried out with a total orientation factor of at least 2, so that an oriented, heat-shrinkable film is produced, the oriented film having a total free shrink at 185° F. of at least 30 percent; and wherein the process is carried out so that the film exhibits: % Transparency≧5.33(% Haze)−31.5.