Methods and devices for processing polymer films

• US 6,936,209 B2
• Filed: 11/27/2002
• Issued: 08/30/2005
• Est. Priority Date: 11/27/2002
• Status: Expired due to Term

• Current Assignee: 3M Innovative Properties Company (3M Company)
• Original Assignee: 3M Innovative Properties Company (3M Company)
• Inventors: Merrill, William Ward, Ruff, Andrew T., Jackson, Jeffery N., Thompson, Desiree L.
• Primary Examiner(s): Lechert, Jr., Stephen J.
• Application Number:
  US10/306,593
• Publication Number:
  US 20040099993A1
• Time in Patent Office: 1,007 Days
• Field of Search: 264/288.4, 264/290.2, 264/291
• US Class Current: 264/288.4
• CPC Class Codes: B29C 55/08 transverse to the direction of feed
• CPC Class Codes: B29C 55/165 Apparatus therefor
• CPC Class Codes: Y10S 425/041 Reshape

Abstract

Stretched polymeric films can be used in a variety of applications, including optical applications. The stretching conditions and shape of the stretching tracks in a stretching apparatus can determine or influence film properties. Take-away systems can be used to receive the film after stretching. The configuration of the take-away system can, in at least some instances, influence final film properties.

Claims

1. A method of processing a film, the method comprising:

holding opposing edge portions of a film using gripping members;

conveying the film along diverging paths and in a machine direction within a stretching region of a stretching apparatus to stretch the film;

receiving the film after stretching in an isolated take-away system by grasping opposing take-away regions of the films using opposing gripping members of the take-away system; and

conveying the film through a portion of the take-away system in which the opposing gripping members are angled toward each other.

2. The method of claim 1, wherein the opposing gripping members are angled toward each other along an entire length of the take-away system.

3. The method of claim 1, wherein the take-away system comprises at least a first set of opposing gripping members and a second set of opposing gripping members, wherein the first set of opposing gripping members are angled toward each other.

4. The method of claim 1, wherein the take-away system comprises at least a first set of opposing gripping members and a second set of opposing gripping members, wherein the second set of opposing gripping members are angled toward each other.

5. The method of claim 1, wherein the portion of the opposing gripping members are angled toward each other at an angle of no more than 3°

relative to the direction along which the film is conveyed.