POLYTETRAFLUOROETHYLENE MIXTURE

• US 20130281558A1
• Filed: 12/21/2011
• Published: 10/24/2013
• Est. Priority Date: 12/21/2010
• Status: Active Grant

• Current Assignee: Daikin Industries Ltd
• Original Assignee: Daikin Industries Ltd
• Inventors: Sawada, Yasuhiko, Kasai, Shunji, Yamanaka, Taku, Ono, Makoto, Shibuya, Yoshiyuki, Inui, Kunihiko, Chaen, Shinichi
• Granted Patent: US 8,865,839 B2
• Time in Patent Office: Days
• US Class Current: 521/134
• CPC Class Codes: B01D 2323/12 Specific ratios of components used
• CPC Class Codes: B01D 67/0027 by stretching
• CPC Class Codes: B01D 71/36 Polytetrafluoroethene
• CPC Class Codes: C08J 2327/18 Homopolymers or copolymers of tetrafluoroethylene
• CPC Class Codes: C08J 5/18 Manufacture of films or sheets
• CPC Class Codes: C08L 2205/02 containing two or more polymers of the same C08L -group
• CPC Class Codes: C08L 2205/025 containing two or more polymers of the same hierarchy C08L, and differing only in parameters such as density, comonomer content, molecular weight, structure
• CPC Class Codes: C08L 27/18 Homopolymers or copolymers or tetrafluoroethene
• CPC Class Codes: C08L 29/10 Homopolymers or copolymers of unsaturated ethers C08L35/08 takes precedence

Abstract

Provided is a material that can be easily biaxially oriented, homogeneously stretched even with a high draw ratio, and formed into a polytetrafluoroethylene porous membrane with low pressure loss. The present invention relates to a polytetrafluoroethylene mixture comprising: a modified polytetrafluoroethylene; and a fibrillable polytetrafluoroethylene homopolymer, the modified polytetrafluoroethylene having an extrusion pressure to a cylinder, at a reduction ratio of 1600, of 70 MPa or higher.

Claims

1. A polytetrafluoroethylene mixture comprising:

a modified polytetrafluoroethylene; and

a fibrillable polytetrafluoroethylene homopolymer,

the modified polytetrafluoroethylene having a cylinder extrusion pressure, at a reduction ratio of 1600, of 70 MPa or higher.

2. The polytetrafluoroethylene mixture according to claim 1,

wherein the modified polytetrafluoroethylene has a cylinder extrusion pressure, at a reduction ratio of 1600, of 80 MPa or higher.

3. The polytetrafluoroethylene mixture according to claim 1,

wherein the mass ratio of the modified polytetrafluoroethylene to the polytetrafluoroethylene homopolymer, that is, modified polytetrafluoroethylene/polytetrafluoroethylene homopolymer, is 10 to 90/90 to 10.

4. The polytetrafluoroethylene mixture according to claim 1,

wherein the modified polytetrafluoroethylene includes a modified monomer unit in an amount of 0.005 to 0.500 wt % of the weight of all monomer units.

5. The polytetrafluoroethylene mixture according to claim 1,

wherein the modified polytetrafluoroethylene has a standard specific gravity (SSG) of 2.130 to 2.185.

6. The polytetrafluoroethylene mixture according to claim 1,

wherein the polytetrafluoroethylene homopolymer has a cylinder extrusion pressure, at a reduction ratio of 100, of 10 to 35 MPa.

7. The polytetrafluoroethylene mixture according to claim 1,

wherein the polytetrafluoroethylene homopolymer has a cylinder extrusion pressure, at a reduction ratio of 100, of 10 to 20 MPa.

8. The polytetrafluoroethylene mixture according to claim 1, obtainable by coagulation of an aqueous dispersion containing the modified polytetrafluoroethylene and the polytetrafluoroethylene homopolymer.

9. A polytetrafluoroethylene porous membrane obtainable by stretching the polytetrafluoroethylene mixture according to claim 1.