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US-20260125202-A1 - CONTAINER

US20260125202A1US 20260125202 A1US20260125202 A1US 20260125202A1US-20260125202-A1

Abstract

The disclosure aims to provide a container in which polytetrafluoroethylene is less likely to fibrillate. The disclosure relates to a container for filling with polytetrafluoroethylene, the container having a columnar shape with an inner wall of a side surface tapered either forward or inversely.

Inventors

  • Ryota USAMI
  • Takaya Yamada
  • Junpei Terada
  • Tsuyoshi Kinoshita
  • Taketo Kato
  • Taku Yamanaka
  • Kohei Yasuda

Assignees

  • DAIKIN INDUSTRIES, LTD.

Dates

Publication Date
20260507
Application Date
20251222
Priority Date
20230630

Claims (20)

  1. 1 . A container for filling with polytetrafluoroethylene, wherein the polytetrafluoroethylene is used as a binder for an electrochemical device; and the container has a columnar shape with an inner wall of a side surface tapered either forward or inversely.
  2. 2 . The container according to claim 1 , wherein the polytetrafluoroethylene has an extrusion pressure at a reduction ratio of 100 of 5 MPa or higher and/or is expandable.
  3. 3 . The container according to claim 1 , wherein the polytetrafluoroethylene has an extrusion pressure at a reduction ratio of 100 of 5 MPa or higher and is expandable.
  4. 4 . The container according to claim 1 , wherein a difference between a top-face inner diameter and a bottom-face inner diameter is 5 to 100 mm.
  5. 5 . The container according to claim 1 , wherein the container has a taper angle of 0.5° to 10°.
  6. 6 . The container according to claim 1 , wherein the container has an inner wall with a surface roughness of 1.00 μm or less.
  7. 7 . The container according to claim 1 , wherein the container includes: a main body with an opening; a lid to be attached to the opening; and a clamp for fixing the lid.
  8. 8 . The container according to claim 7 , wherein the lid is attached to the opening in a state where a step provided on the lid is engaged with a protrusion provided on the main body and/or in a state where a protrusion provided on the lid is engaged with a step provided on the main body.
  9. 9 . The container according to claim 1 , wherein the polytetrafluoroethylene has a water content of 0.050% by mass or less.
  10. 10 . The container according to claim 1 , wherein the polytetrafluoroethylene has an apparent density of 0.40 to 0.60 g/ml.
  11. 11 . The container according to claim 1 , wherein the polytetrafluoroethylene has a powder particle size of 300 to 700 μm.
  12. 12 . The container according to claim 1 , wherein the polytetrafluoroethylene has a standard specific gravity of 2.200 or less.
  13. 13 . The container according to claim 1 , wherein the polytetrafluoroethylene is a homopolymer of tetrafluoroethylene or a modified polytetrafluoroethylene containing a polymerized unit based on tetrafluoroethylene and a polymerized unit based on a modifying monomer.
  14. 14 . The container according to claim 1 , wherein the container is filled with the polytetrafluoroethylene.
  15. 15 . The container according to claim 1 , wherein the container includes a desiccant.
  16. 16 . A method for storing polytetrafluoroethylene, comprising storing the polytetrafluoroethylene by filling the container according to claim 1 with the polytetrafluoroethylene.
  17. 17 . A container for filling with polytetrafluoroethylene, wherein the polytetrafluoroethylene is used as a binder for an electrochemical device; and the polytetrafluoroethylene used to fill the container has a mass of 10 kg or less.
  18. 18 . The container according to claim 17 , wherein the polytetrafluoroethylene has a water content of 0.005% by mass or less, an apparent density of 0.35 to 0.48 g/ml, a powder particle size of 100 μm or larger and smaller than 600 μm, and a standard specific gravity of 2.130 to 2.170.
  19. 19 . The container according to claim 17 , wherein the polytetrafluoroethylene has a powder particle size of 100 μm or larger and smaller than 300 μm and/or an apparent density of 0.35 g/ml or more and less than 0.40 g/ml.
  20. 20 . The container according to claim 17 , wherein the container is filled with the polytetrafluoroethylene.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS This application is a Rule 53(b) Continuation of International Application No. PCT/JP2024/023636 filed Jun. 28, 2024, which claims priority based on Japanese Patent Application No. 2023-107710 filed Jun. 30, 2023, the respective disclosures of which are incorporated herein by reference in their entirety. TECHNICAL FIELD The disclosure relates to containers for filling with polytetrafluoroethylene. BACKGROUND ART Patent Literatures 1 and 2 each describe use of an aqueous dispersion of polytetrafluoroethylene as a binder for batteries. CITATION LIST Patent Literature Patent Literature 1: JP 2004-31179 APatent Literature 2: JP H11-343317 A SUMMARY The disclosure (1) relates to a container for filling with polytetrafluoroethylene, the container having a columnar shape with an inner wall of a side surface tapered either forward or inversely. Advantageous Effects The disclosure can provide a container in which polytetrafluoroethylene is less likely to fibrillate. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic view of an example of a container of the disclosure. FIG. 2 is a partial enlarged view of the container in FIG. 1. FIG. 3 is a schematic view of a clamp included in the container in FIG. 1. FIG. 4 is a schematic view of a modified example of the container of the disclosure. FIG. 5 is a schematic view of a modified example of the container of the disclosure. FIG. 6 is a partial enlarged view of a modified example of the container of the disclosure. FIG. 7 is a schematic view of a modified example of the container of the disclosure. DESCRIPTION OF EMBODIMENTS The present inventors examined polytetrafluoroethylene to find out that polytetrafluoroethylene that is useful as a binder for electrochemical devices such as batteries tends to fibrillate more easily than normal polytetrafluoroethylene during storage or transportation in a filled container. In applications where large amounts of polytetrafluoroethylene are used, fibrillation of a portion of polytetrafluoroethylene is not a major problem. However, in an application where polytetrafluoroethylene is used as a binder for electrochemical devices, the effect of fibrillation is significant as the amount used is small, which strongly requires fibrillation control. As a result of further studies, the present inventors found out that fibrillation is prevented or reduced when polytetrafluoroethylene is in a container having a columnar shape with its inner wall of the side surface tapered either forward or inversely, arriving at the first aspect of the disclosure. The present inventors also found out that limitation on the mass of polytetrafluoroethylene used to fill the container to 10 kg or less prevents or reduces fibrillation of the polytetrafluoroethylene in the container, arriving at the second aspect of the disclosure. The disclosure will be specifically described hereinbelow. The first aspect of the disclosure relates to a container for filling with polytetrafluoroethylene. The container has a columnar shape with its inner wall of the side surface tapered either forward or inversely. Polytetrafluoroethylene (PTFE) in a container hardens when PTFE powder (particles) is crushed and compacted under its own weight. The PTFE powder typically needs to be loosened before use. Fibrillation is thought to occur during the loosening of such hardened powder. In the container according to the first aspect of the disclosure with its inner wall of the side surface tapered either forward or inversely, PTFE powder is less likely to be compacted as the force generated by its own weight is less likely to be applied thereto. Thus, fibrillation is prevented or reduced. In the container according to the first aspect of the disclosure, the mass of PTFE used to fill the container is preferably 30 kg or less, more preferably 20 kg or less, still more preferably 15 kg or less. The lower limit thereof is normally, but not limited to, 1 kg or more. The upper limit of the inner capacity of the container according to the first aspect of the disclosure is preferably 150 L or less, more preferably 120 L or less, still more preferably 100 L or less, further preferably 80 L or less. The lower limit thereof is preferably, but not limited to, 5 L or more, more preferably 10 L or more, still more preferably 20 L or more. An example of the container according to the first aspect of the disclosure is described hereinbelow with reference to drawings. As shown in FIG. 1, a container 1 includes a main body 2, a lid 3, and a clamp 4. The main body 2 is a columnar component in which an inner wall 2a and an outer wall 2b of the side surface are tapered forward. The main body 2 is filled with PTFE through an opening 2c on the top face. After filling with PTFE, the inside of the main body 2 is sealed by attaching the lid 3 to the opening 2c of the main body 2 and fixing the lid 3 with the clamp 4. The lid 3 is a circular component configured to cover the o