METHODS AND DEVICES FOR PROCESSING POLYMER FILMS

• US 20070098829A1
• Filed: 11/28/2006
• Published: 05/03/2007
• Est. Priority Date: 11/27/2002
• Status: Abandoned Application

• Current Assignee: 3M Innovative Properties Company (3M Company)
• Original Assignee: 3M Innovative Properties Company (3M Company)
• Inventors: Merrill, William, Ruff, Andrew, Jackson, Jeffery, Thompson, Desiree
• Application Number:
  US11/563,707
• Publication Number:
  US 20070098829A1
• Time in Patent Office: Days
• US Class Current: 425/66
• 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. An apparatus for processing a film, the apparatus comprising:

a conveyor configured and arranged to convey the film along a machine direction within the apparatus, the conveyor comprising gripping members that are configured and arranged to hold opposing edge portions of the film, and a portion of the conveyor is configured and arranged to provide diverging paths along which the gripping members move to stretch the film; and

an isolated take-away system that receives the film from the conveyor after stretching the film, the take-away system comprising opposing tracks and gripping members configured and arranged to grasp opposing take-away regions of the film after a desired amount of stretching and convey the opposing take-away regions of the film along the opposing tracks, wherein the opposing tracks define a region in which at least a portion of at least one of the opposing tracks is angled with respect to the machine direction.

2. The apparatus of claim 1, wherein the opposing tracks are angled with respect to each other.

3. The apparatus of claim 2, wherein the opposing tracks are angled toward each other.

4. The apparatus of claim 2, wherein the opposing tracks are angled away from each other.

5. The apparatus of claim 2, wherein the opposing tracks are angled with respect to each other along an entire length of the opposing tracks.

6. The apparatus of claim 2, wherein the take-away system is disposed at an angle relative to the machine direction.

7. The apparatus of claim 1, wherein the opposing tracks are disposed at an angle of at least 10 with respect to the machine direction.

8. The apparatus of claim 7, wherein the opposing tracks are disposed at different angles with respect to the machine direction.

9. The apparatus of claim 7, wherein the opposing tracks of the take-away system are configured and arranged to grasp the opposing take-away regions of the film at a position in which the opposing take-away regions of the film have a same transverse directional draw ratio.

10. The apparatus of claim 7, wherein the opposing tracks of the take-away system are configured and arranged to grasp the opposing take-away regions of the film at a position in which the opposing take-away regions of the film have different transverse directional draw ratios.

11. The apparatus of claim 7, wherein the diverging paths of the conveyor are configured and arranged to stretch the film so that a centerline of the film is angled with respect to a machine direction of the conveyor prior to stretching the film.

12. An apparatus for processing a film, the apparatus comprising:

a conveyor comprising gripping members that hold opposing edge portions of the film and convey, under influence of a drive member, the film along a machine direction within the apparatus, wherein a portion of the conveyor is configured and arranged to provide diverging paths along which the gripping members move to stretch the film; and

an isolated take-away system that receives the film from the conveyor after stretching the film, the take-away system comprising opposing tracks and a plurality of gripping members configured and arranged to grasp opposing take-away regions of the film after a desired amount of stretching and convey the opposing take-away regions of the film along the opposing tracks, wherein the apparatus is configured and arranged to allow selection of a final transverse direction draw ratio of the film by changing a position of the isolated take-away system with respect to a position of the conveyor.

13. An apparatus for processing a film, the apparatus comprising:

a conveyor configured and arranged to convey the film along a machine direction, the conveyor comprising gripping members that are configured and arranged to hold opposing edge portions of the film;

a stretching region in which the gripping members are configured and arranged to travel along diverging paths to stretch the film; and

a post-conditioning region disposed after the stretching region and comprising at least one zone in which the gripping members are configured and arranged to travel along converging paths.