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US-20260124640-A1 - METHOD FOR MANUFACTURING COATED FILM

US20260124640A1US 20260124640 A1US20260124640 A1US 20260124640A1US-20260124640-A1

Abstract

A coated film having good characteristics is manufactured. A method for manufacturing the coated film includes: (a) a step of applying a coating liquid 20 a to a first surface of a base material 1 unwound from an unwinding unit UW; (b) a step of forming a coating layer 3 b on the first surface of the base material 1 by drying the coating liquid (coating film 3 a ) on the base material 1 ; and (c) a step of winding the base material 1 on which the coating layer 3 b has been formed in a winding unit WD. Also, the base material 1 is continuously arranged from the unwinding unit UW to the winding unit WD, tension cut of the base material 1 is performed by a first suction roll SR after the base material 1 is taken out from the unwinding unit UW and before the step (b), and tension cut of the base material 1 on which the coating layer 3 b has been formed is performed by a second suction roll SR before the step (c).

Inventors

  • Ryo ISHIGURO
  • Satoru Nakamura

Assignees

  • THE JAPAN STEEL WORKA, LTD.

Dates

Publication Date
20260507
Application Date
20251222
Priority Date
20191023

Claims (10)

  1. 1 . A method for manufacturing a coated film comprising: (a) a step of applying a coating liquid to a first surface of a base material taken out from an unloading unit; (b) a step of forming a coating layer on the first surface of the base material by drying the coating liquid on the base material; and (c) a step of taking in the base material on which the coating layer has been formed in a loading unit, wherein the base material is continuously arranged from the unloading unit to the loading unit, wherein tension cut of the base material is performed by a first suction roll after the base material is taken out from the unloading unit and before the step (b), and wherein tension cut of the base material on which the coating layer has been formed is performed by a second suction roll before the step (c).
  2. 2 . The method for manufacturing the coated film according to claim 1 , wherein a suction pressure of each of the first suction roll and the second suction roll is 3 MPa or less.
  3. 3 . The method for manufacturing the coated film according to claim 1 , wherein the base material is a porous film.
  4. 4 . The method for manufacturing the coated film according to claim 1 , wherein the base material on which the coating layer has been formed is a separator for a battery.
  5. 5 . The method for manufacturing the coated film according to claim 1 , wherein a film thickness of the base material is less than 9 μm.
  6. 6 . The method for manufacturing the coated film according to claim 1 , wherein a film thickness of the base material is 7 μm or less, and a loading tension in the loading unit is less than 12 N.
  7. 7 . The method for manufacturing the coated film according to claim 1 , wherein a loading speed of the base material in the loading unit is 30 m/min or more.
  8. 8 . The method for manufacturing the coated film according to claim 1 , wherein a drying temperature is less than 75° C.
  9. 9 . The method for manufacturing the coated film according to claim 1 , wherein the step (a) is performed by using a chamber for storing the coating liquid and a gravure coating device having a coating roll, and wherein the chamber is arranged sideways.
  10. 10 . The method for manufacturing the coated film according to claim 1 , wherein the step (b) is performed in a drying processing unit in which a heating fluid is introduced from a nozzle arranged in a drying chamber, and wherein a temperature of the drying chamber is controlled by a temperature sensor arranged between the nozzle and a side wall of the drying chamber on an upstream side in a conveyance direction of the base material.

Description

TECHNICAL FIELD The present invention relates to a method for manufacturing a coated film and an apparatus for manufacturing a coated film, and particularly relates to a method and an apparatus for manufacturing a coated film used in a separator of a battery or the like. BACKGROUND ART In recent years, batteries such as lithium ion batteries have been actively used for automobiles and infrastructure. In a battery such as a lithium ion battery, a positive electrode material and a negative electrode material are separated by a porous film called a separator. The separator has, for example, a plurality of micropores through which lithium ions can pass, and charging and discharging can be repeated by the lithium ions moving between the positive electrode material and the negative electrode material through the pores. As described above, the separator has a role of separating the positive electrode material and the negative electrode material to prevent a short circuit. In addition, when the temperature inside the battery becomes high for some reason, the micropores of the separator are closed to stop the movement of lithium ions, thereby stopping the battery function (shutdown function). As described above, the separator plays a role of a battery safety device, and it is important to improve the mechanical strength and heat resistance of the separator. For example, Patent Document 1 (Japanese Unexamined Patent Application Publication No. 2016-183209) discloses a technique of forming a coating layer containing inorganic particles and a binder resin composition on at least one surface of a polyolefin resin porous film. Further, Patent Document 2 (Japanese Unexamined Patent Application Publication No. 2017-068900) discloses a technique of forming a coating layer by applying a coating liquid containing a filler and a resin binder on a polyolefin-based resin porous film and then drying the liquid. RELATED ART DOCUMENTS Patent Documents Patent Document 1: Japanese Unexamined Patent Application Publication No. 2016-183209Patent Document 2: Japanese Unexamined Patent Application Publication No. 2017-068900 SUMMARY OF THE INVENTION Problems to be Solved by the Invention The inventors of the present invention have conducted research and development on a coating technique for forming a coating layer on a surface of a base material in order to improve the mechanical strength and heat resistance of the base material (porous film) of the separator of the battery. In the process of the research and development, wrinkles and drying defects occurred on the base material in the coating and drying processing of the coating liquid, and a favorable coating technique was found as a result of diligent studies on the elimination of these problems. Other problems and novel features will be apparent from the description of this specification and accompanying drawings. Means for Solving the Problems A method for manufacturing a coated film disclosed in this application includes: (a) a step of applying a coating liquid to a first surface of a base material taken out from an unloading unit; (b) a step of forming a coating layer on the first surface of the base material by drying the coating liquid on the base material; and (c) a step of taking in the base material on which the coating layer has been formed in a loading unit. The base material is continuously arranged from the unloading unit to the loading unit, tension cut of the base material is performed by a first suction roll after the base material is taken out from the unloading unit and before the step (b), and tension cut of the base material on which the coating layer has been formed is performed by a second suction roll before the step (c). An apparatus for manufacturing a coated film disclosed in this application includes: an unloading unit from which a base material is taken out; a coating unit configured to apply a coating liquid to a first surface of the base material; a drying unit configured to form a coating layer on the first surface of the base material by drying the coating liquid on the base material; and a loading unit configured to load the base material on which the coating layer has been formed. A first suction roll is arranged between the unloading unit and the drying unit, and a second suction roll is arranged between the drying unit and the loading unit. Effects of the Invention According to the method for manufacturing a coated film disclosed in this application, it is possible to manufacture a coated film having good characteristics. According to the apparatus for manufacturing a coated film disclosed in this application, it is possible to manufacture a coated film having good characteristics. BRIEF DESCRIPTIONS OF THE DRAWINGS FIG. 1 is a diagram schematically showing a configuration of an apparatus for manufacturing a coated film according to the first embodiment; FIG. 2 is a cross-sectional view showing a process for forming the coated film according to the