Cryovac, Inc.

Christopher K Robinson

Nathanael Rustia Miranda

Richard M Dayrit

Frank M Hofmeister

Michael Broadus

Bryan Freeman

Brian P Rivers

Roger D Vrooman

Marvin Russell Havens

Matthew D Dawe

Robert W Campbell

George D Bolden

Emmet Austin

Josh E Johnston

Michael E Broadus

George W Bolden

Bryan E Freeman

As a first aspect, the present invention is directed to a process for making a heat-shrinkable annular film, comprising: (A) extruding an annular extrudate downward from an annular die; (B) quenching the annular extrudate by applying a quenching liquid to the annular extrudate; (C) reheating the extrudate to an orientation temperature of from 130&#xb0; F. to 210&#xb0; F., resulting in a reheated annular extrudate; and (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 the resulting oriented, heat-shrinkable film has a total free shrink at 185&#xb0; F. of at least 10 percent. The extrudate comprises at least one semi-crystalline polyamide selected from the group consisting of: (i) polyamide 6, (ii) polyamide 66, (iii) polyamide 6/66, and (iv) polyamide 6/12. The semi-crystalline polyamide makes up at least 5 volume percent of the annular extrudate. At least 50% of the quenching liquid cascades down the annular extrudate for a distance of at least 2 inches. The quenching liquid makes initial contact with the annular extrudate within 0.1 to 8 inches of the annular die.

Process for making shrink film comprising rapidly-quenched semi-crystalline polyamide

A multilayer, heat-shrinkable film contains at least one semi-crystalline polyamide selected from the group consisting of polyamide 6, polyamide 66, polyamide 6/66, and polyamide 6/12. The film may have a total semi-crystalline polyamide content of at least 35 volume percent, based on total film volume, and a total free shrink at 185&#xb0; F. of at least 35 percent. The film may have an FTIR Transmission Absorbance A/Aratio of up to 1.65. The film may be a retortable film, capable of being used in a process for preparing a retorted packaged product. A process for making a heat-shrinkable annular film containing the semi-crystalline polyamide comprises extruding an annular extrudate downward from an annular die, quenching the annular extrudate by applying a quenching liquid to the annular extrudate, reheating the extrudate to an orientation temperature, and 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, to produce a film having a total free shrink at 185&#xb0; F. of at least 10 percent.

Shrink film containing semi-crystalline polyamide and process for making same

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Moore, SC, United States of America

Christopher K Robinson