Search

CN-117142201-B - Film roll and method for manufacturing same

CN117142201BCN 117142201 BCN117142201 BCN 117142201BCN-117142201-B

Abstract

Means are provided to further reduce the sticking of the film roll and the roll bias. When the film roll having no embossed portion is set to X (unit: μm) and the film thickness deviation including the film end is set to Y (unit: μm), the film roll having 0.05 μm < X <0.50 μm..equation (1) 0.7< X/Y < 2.0..equation (2) satisfies the following equations (1) and (2).

Inventors

  • Gu Shan Zhi Zheng
  • KANEKO YOSHIYUKI
  • MASUDA OSAMU
  • NANJO TAKASHI

Assignees

  • 柯尼卡美能达株式会社

Dates

Publication Date
20260508
Application Date
20230529
Priority Date
20220601

Claims (7)

  1. 1. A film roll having no embossed portion, characterized in that when X is a film interlayer gap in the roll measured on a side surface of the film roll and Y is a film thickness deviation including a film end, the following expressions (1) and (2) are satisfied: 。
  2. 2. a roll of film as claimed in claim 1, wherein, The standard deviation sigma of the inter-film gap in the film roll, the inter-film gap in the roll and the inter-film gap in the film roll is 0.15 or less.
  3. 3. A film roll as claimed in claim 1 or 2, characterized in that, Comprising cycloolefin resin.
  4. 4. A method for manufacturing a film roll, comprising: a stretching step of locally heating the film by using a plurality of infrared heaters and stretching the film while controlling film thickness deviation Y including film end portions, and A winding step of winding the film while controlling a film interlayer gap X measured on a side surface of the film roll, The X and Y satisfy the following expressions (1) and (2): 。
  5. 5. The method of producing a film roll according to claim 4, wherein, The standard deviation sigma of the inter-film gap in the film roll, the inter-film gap in the roll and the inter-film gap in the film roll is 0.15 or less.
  6. 6. The method for producing a film roll according to claim 4 or 5, wherein, The film roll includes a cycloolefin resin.
  7. 7. A polarizing plate comprising a film obtained from the film roll according to claim 1 or 2.

Description

Film roll and method for manufacturing same Technical Field The present invention relates to a film roll and a method for manufacturing the same. Background In recent years, with the drastic price competition of liquid crystal televisions, polarizing plate manufacturers are researching cost reduction measures to reduce switching losses and the like. More specifically, the polarizing plate is produced by bonding the polarizer and the optical film, but in order to reduce the production time due to the above-described switching loss, studies for providing a long optical film roll have been conducted in manufacturers for producing the optical film. However, since the length of the film roll is long and the weight of the roll is increased, it is more difficult to uniformly adjust the stress balance from the roll core to the outside of the roll, and it is an object to provide a film roll which maintains a high-quality roll state without deformation with time. Conventionally, from the viewpoint of productivity, cost, and the like, a film roll in which an optical film embossed at an end portion of the film is wound has been industrially used. As main functions of the embossing processing portion, the following two are considered: 1) Adhesion is suppressed by taking up a gap (also referred to as an air layer) between the films. 2) The winding displacement caused by the physical concave-convex is suppressed. In addition, immediately after the film roll is rolled up (immediately after production), the aforementioned gap (air layer) between the films suppresses adhesion of the product surfaces to each other. However, during transportation (transportation in sea, trucks, etc.) or storage in a warehouse, a phenomenon occurs in which gaps (air layers) between films disappear with the passage of time. Since there are few cases where production is started by immediately using film rolls stored in a warehouse, and there are cases where film rolls are stored in a warehouse for a long period of time, improvement in the adhesion-related custody is required. Further, since vibration and impact generated during transportation by a truck or the like easily cause winding displacement of the film roll, and also are affected by seasonal fluctuations, control is very difficult, and even if an optical film embossed at the end portion is wound, improvement is required. Here, patent document 1 discloses an optical film having knurled ends and a roll body having an air layer wound therein. Patent document 2 discloses a method for producing an optical film by winding an optical film around a winding shaft while embossing both ends of the film, in which the embossing height is varied with respect to the winding diameter, thereby maintaining a constant film interlayer gap in the wound roll. Patent document 3 discloses a technique for improving the quality of a retardation film, wherein the film thickness unevenness (variation) of the film is set to a specific range. Prior art literature Patent literature Patent document 1 Japanese patent laid-open No. 2009-208358 Patent document 2 Japanese patent application laid-open No. 2013-46966 Patent document 3 Japanese patent laid-open No. 2007-254699 Disclosure of Invention Problems to be solved by the invention However, in the technology described in the above patent document, the adhesion of the film roll and the reduction of the winding displacement are insufficient, and further improvement is demanded. It is therefore an object of the present invention to provide a means for further reducing the sticking and winding displacement of a film roll. Means for solving the problems The present inventors have repeatedly made intensive studies. As a result, the present invention has been completed by finding that the above problems are solved by the following film roll. That is, the present invention is a film roll having no embossed portion, and satisfies the following expressions (1) and (2) when X (unit: μm) is a film interlayer gap in a roll measured on a side surface of the film roll and Y (unit: μm) is a film thickness deviation including an end portion of the film: [ 1] 。 Effects of the invention According to the present invention, means for further reducing the adhesion of the film roll and the winding displacement can be provided. Drawings Fig. 1 is a schematic diagram showing an example of an imaging unit included in an imaging device used for measuring a gap between layers. Fig. 2 is a schematic diagram showing an example of an imaging device used for measuring a gap between film layers. Fig. 3 is a diagram showing an example of a system configuration of an imaging device used for measuring a gap between layers. Fig. 4 is a schematic diagram showing an example of a method and a measurement result of measuring a film interlayer gap. Fig. 5 is a schematic diagram showing an example of a method and a measurement result of measuring a film interlayer gap. Fig. 6 is a schematic diagram showing an ex