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JP-7856490-B2 - Film stretching apparatus and film manufacturing method

JP7856490B2JP 7856490 B2JP7856490 B2JP 7856490B2JP-7856490-B2

Inventors

  • 増田 友昭

Assignees

  • 株式会社カネカ

Dates

Publication Date
20260511
Application Date
20220602

Claims (8)

  1. A pair of guide rollers, each extending in the width direction of a polyimide film, are positioned spaced apart in the conveying direction and conveyed under tension in the conveying direction, A heating unit that heats the film between the pair of guide rollers by thermal radiation, A pair of nip rollers are positioned on the downstream guide roller in the aforementioned transport direction, and each of the ends of the film is sandwiched between them and the guide roller, Equipped with , The surface roughness of the downstream guide roller has a maximum height of 1.6S or less. The nip roller is a rubber roller in which a roller core is coated with nitrile rubber, and the rotation axis is arranged such that it forms an angle greater than 5° and less than or equal to 30° with respect to the rotation axis of the downstream guide roller, so as to pull the film outward in the width direction .
  2. The film stretching apparatus according to claim 1, wherein the pair of nip rollers are arranged to contact 1.0% to 15% of the total width of the film.
  3. The film stretching apparatus according to claim 1 or 2, wherein the diameter of the guide roller is 10 mm or more.
  4. A film stretching apparatus according to claim 1 or 2, wherein uniaxial stretching is performed by the speed ratio of the pair of guide rollers.
  5. The film stretching apparatus according to claim 1 or 2, wherein the heating section has an infrared heater.
  6. A method for manufacturing a film using the film stretching apparatus according to claim 1 or 2.
  7. The method for manufacturing a film according to claim 6 , wherein the glass transition temperature of the film is 80°C to 250°C.
  8. The method for producing the film according to claim 6 , wherein the film is a transparent polyimide having a total light transmittance of 80% or more at a thickness of 50 μm.

Description

This invention relates to a film stretching apparatus and a film manufacturing method. In the manufacturing of films such as thermoplastic resin films, a technique is known in which the film itself is heated and tension is applied in the direction of film transport to stretch the film. Due to thermal expansion of the film, wrinkles may occur. As a technique to reduce wrinkle formation, Patent Document 1 discloses generating tension in the width direction of the film using a cross guide. Patent Document 2 discloses arranging cross guides to clamp the film's widthwise edges from both sides, thereby applying strain to the film. Patent Document 3 discloses having a nip roller to grip the film's edges, thereby applying tensile force in the width direction to the film. Patent Document 4 discloses providing a pair of rotatable discs at both sides of the film's width direction in a moving film, so as to apply an expanding force to the film. Patent Document 5 discloses arranging cross guides near both ends of the film's width direction while it is being transported. Japanese Patent Publication No. 2017-037290Japanese Patent Publication No. 2009-203055Japanese Unexamined Patent Publication No. 62-263023Japanese Unexamined Patent Publication No. 60-076318Japanese Patent Publication No. 2007-261773 This is a perspective view showing an example of the schematic configuration of a film stretching apparatus according to an embodiment of the present invention.This is a perspective view showing the internal structure of a second guide roller according to an embodiment of the present invention.This is a perspective view showing the arrangement of the nip roller with respect to the rotation axis of the second guide roller according to an embodiment of the present invention. [Technical concept of the embodiment of the present invention] Conventional film stretching equipment used an oven to heat the film itself. As a result, it took a long time from preheating to full heating, and to improve production efficiency, a very long oven was used along the direction of film transport. This increased the fixed costs of production equipment, which was a problem. In some cases, the long heating time caused a deterioration in the properties of the film. Therefore, the applicant decided to adopt a film stretching device using an infrared heater, particularly a far-infrared heater, which can heat the film in a short time. While this type of film stretching device can achieve stretching in a small space, it was found that it could induce wrinkles and other appearance defects in the film during processing. Therefore, it was necessary to take measures to address this while maintaining a compact configuration. The inventors of this invention have discovered that by providing nip rollers that nip both ends of the film on the roller downstream of the film heating region of a film stretching device, it is possible to widen the film in a compact configuration and reduce the occurrence of wrinkles and other defects in the film, thus completing the present invention. The following will provide a detailed explanation based on the diagrams. [Embodiment] (Overview of the film stretching device 100) Figure 1 is a perspective view showing an example of the schematic configuration of a film stretching apparatus 100 according to one embodiment of the present invention. In Figure 1, the X-axis direction is the left-right direction, the Y-axis direction is the front-back direction, and the Z-axis direction is the up-down direction. The Y-axis direction is also the width direction of the film F being transported. The film stretching device 100 comprises a first guide roller 1 and a second guide roller 2, a heater (heating unit) 3, and a nip roller 4. The film F is conveyed from the first guide roller 1 to the second guide roller 2 in the left-right direction (X-axis direction). The film stretching device 100 further includes drive rollers (not shown) upstream of the first guide roller 1 and downstream of the second guide roller 2, respectively, which provide driving force for conveying the film F. As the film F is conveyed, the first guide roller 1 and the second guide roller 2, which are in frictional contact with the film F, also rotate. Preferably, the film stretching device 100 is a device that uniaxially stretches the film F in the conveying direction by the difference in peripheral speed (speed ratio) of the spaced-apart drive rollers, that is, by the speed ratio of the first guide roller 1 and the second guide roller 2. In other words, it is preferable that the stretching is performed by the tension applied to the film F and heating by the heater 3. In this case, by monitoring the tension and feeding back the speed of the drive roller, it is possible to reduce thickness variations in the conveying direction and improve the accuracy of the stretching ratio. (film) The film F is, for example, a thermoplastic film. When the film F is a thermoplastic film,