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Methods respectively for producing unbaked polytetrafluoroethylene film and porous membrane provided with same

A polytetrafluoroethylene and tetrafluoroethylene technology, which is applied in the field of unsintered polytetrafluoroethylene films, can solve the problem of removing uneven particle configuration and uneven scars on the surface and inside of the forming aid film, stretched films and porous films Particles, inability to perform uniform surface treatment, etc., to achieve the effects of improved lamination, improved uniformity, and improved tensile strength

Active Publication Date: 2021-07-30
CHONGQING BAOMAN NEW MATERIAL CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0016] In this way, the surface and internal particles of the film without the forming aid are not uniformly arranged and there are uneven spots The main reason
[0017] In addition, when a surface treatment liquid in which sodium metal is dispersed in a petroleum-based solvent is applied to the surface of the green PTFE film, since gaps exist on the surface of the green PTFE film as described above, the surface treatment liquid Sparsely permeates the surface of the unsintered PTFE film, so there is a problem that uniform surface treatment cannot be performed

Method used

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  • Methods respectively for producing unbaked polytetrafluoroethylene film and porous membrane provided with same
  • Methods respectively for producing unbaked polytetrafluoroethylene film and porous membrane provided with same
  • Methods respectively for producing unbaked polytetrafluoroethylene film and porous membrane provided with same

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0083] As the PTFE fine powder, polytetrafluoroethylene F-106 (manufactured by Daikin Industries, Ltd.) was used.

[0084] As a molding aid, petroleum solvent Isopar H (manufactured by ExxonMobil Corporation) was used.

[0085] 22 parts by weight of the molding aid were added to 100 parts by weight of the PTFE fine powder to prepare a mixture (preform) of the PTFE fine powder and the molding aid.

[0086] The mixture is filled in an extrusion die, and the mixture is extruded from the extrusion die to produce a sheet-shaped extruded product.

[0087] This extruded product was rolled with a press roll to make it into a thin film.

[0088] The forming aid was dried and removed by heating the film in a heating oven to prepare a film having a width of 155 mm and a thickness of 295 μm without the forming aid.

[0089] Under the environment of room temperature 26 ℃, use the nip roller to compress the described thin film that removes forming aid, make the unsintered high-density PTF...

Embodiment 2

[0107] With respect to 100 parts by weight of the PTFE fine powder of Example 1, a mixture (preform) added by changing from 22 parts by weight of the molding aid of Example 1 to 20 parts by weight was prepared; The thickness of the molding aid film is 272 μm (the density increases to 1.62 g / cm with the thickness change 3 ), except that, in the same manner as in Example 1, the molding aid-removed film of Example 2 was produced.

[0108] The molding aid-removed film of Example 2 was compressed by a nip roll at a linear pressure of 50 kg / cm.

[0109] As a result, the thickness decreased from 272 μm to 195 μm (28.3% reduction rate), and the density increased to 2.17 g / cm 3 . The compressed film was free from waviness and fracture and became translucent.

Embodiment 3

[0111] The molding aid-removed film of Example 2 was compressed by a nip roll at a linear pressure of 100 kg / cm.

[0112] As a result, the thickness decreased from 272 μm to 187 μm (31.3% reduction rate), and the density increased to 2.24 g / cm 3 . The compressed film was free from waviness and fracture and became translucent.

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Abstract

The purpose of the present invention is to provide: a method for producing an unbaked PTFE film having a uniform density distribution and an increased density, whereby it becomes possible to produce the unbaked PTFE film continually; and a method for producing a porous membrane that does not have unevenness with respect to the thickness and density thereof. The method for producing an unbaked PTFE film according to the present invention is characterized by comprising: filling an extrusion molding mold with a mixture prepared by adding a molding auxiliary agent to a PTFE fine powder; extruding the mixture from the extrusion molding mold to produce an extrusion molded product; rolling the extrusion molded product with a roller and then removing the molding auxiliary agent therefrom to produce a molding-auxiliary-agent-removed film; and pressing the molding-auxiliary-agent-removed film under ambient temperature while nipping the film with a nip roll equipped with a rubber roll that is composed of a metal-made axis core coated with a rubber to decrease the thickness of the molding-auxiliary-agent-removed film until the density becomes 2.0 g / cm3 or more.

Description

technical field [0001] The present invention is a method for preparing a high-density unsintered polytetrafluoroethylene film (hereinafter, "polytetrafluoroethylene" is abbreviated as "PTFE") and a method for preparing a PTFE porous membrane using the unsintered PTFE film. . [0002] In addition, in this specification, the PTFE which has not gone through the process of heating to 340 degreeC or more is called unsintered PTFE. Incidentally, the melting point of PTFE is 340°C, and the melting point of sintered PTFE is 327°C. Background technique [0003] A PTFE porous membrane is generally produced as follows. That is, a paste obtained by adding a solvent such as petroleum solvent as a molding aid to PTFE fine powder obtained by emulsion polymerization of tetrafluoroethylene (hereinafter, "tetrafluoroethylene" will be abbreviated as "PTFE") The mixture is filled into a cylinder as an extrusion die. Then, the pasty mixture is extruded in a rod or sheet form from the extrusi...

Claims

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Application Information

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IPC IPC(8): B29B11/14B29C55/02B29C43/24B29C67/04B29C48/30
CPCB29B11/14B29C43/24B29C55/02B29C67/04C08J5/18C08J9/26B29K2027/18B29C48/0011B29C48/0018B29C48/022B29C71/02C08J2327/18C08J7/12B29C49/071B29C2949/0715B29C48/002B29C55/06B29C71/0009B29C55/12B29C55/023
Inventor 山本勝年泽井美智子增田亚沙美及川茂美
Owner CHONGQING BAOMAN NEW MATERIAL CO LTD
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