METHOD FOR PRODUCING AQUEOUS POLYTETRAFLUOROETHYLENE DISPERSION

• US 20140200310A1
• Filed: 08/27/2012
• Published: 07/17/2014
• Est. Priority Date: 08/25/2011
• Status: Active Grant

• Current Assignee: Daikin Industries Ltd
• Original Assignee: Daikin Industries Ltd
• Inventors: Taira, Takahiro, Yamanaka, Taku, Nanba, Yoshinori, Tanaka, Atsuko, Ono, Makoto, Tsuda, Nobuhiko, Kato, Taketo
• Granted Patent: US 9,580,590 B2
• Time in Patent Office: Days
• US Class Current: 524/758
• CPC Class Codes: C08F 114/26 Tetrafluoroethene
• CPC Class Codes: C08F 2/22 Emulsion polymerisation
• CPC Class Codes: C08F 2/24 with the aid of emulsifying agents
• CPC Class Codes: C08F 2/26 anionic
• CPC Class Codes: C08F 2/30 non-ionic
• CPC Class Codes: C08F 214/26 Tetrafluoroethene
• CPC Class Codes: C08F 214/262 with fluorinated vinyl ethers
• CPC Class Codes: C08L 27/18 Homopolymers or copolymers or tetrafluoroethene

Abstract

The present invention aims to provide a novel method for producing an aqueous dispersion containing non-melt-processable polytetrafluoroethylene particles. The present invention relates to a method for producing an aqueous dispersion containing non-melt-processable polytetrafluoroethylene particles, the method including polymerizing tetrafluoroethylene in an aqueous medium in the presence of perfluoro hexanoic acid or its salt.

Claims

1. A method for producing an aqueous dispersion containing non-melt-processable polytetrafluoroethylene particles, the method comprising

polymerizing tetrafluoroethylene in an aqueous medium in the presence of perfluoro hexanoic acid or its salt.

2. The method according to claim 1,

wherein tetrafluoroethylene is polymerized further in the presence of fluoropolyether acid having a molecular weight of at least 800 g/mol or its salt (1).

3. The method according to claim 2,

wherein the fluoropolyether acid or its salt (1) has at least one repeated structure selected from the group consisting of repeated structures represented by the formulae (1a) to (1d):

(—

CFCF₃—

CF₂—

O—

)_n 

 

(1a);

(—

CF₂—

CF₂—

CF₂—

O—

)_n 

 

(1b);

(—

CF₂—

CF₂—

O—

)_n—

(—

CF₂—

O—

)_m 

 

(1c); and

(—

CF₂—

CFCF₃—

O—

)_n—

(—

CF₂—

O—

)_m 

 

(1d),

wherein m and n each represent an integer of 1 or more.

4. The method according to claim 1,

wherein tetrafluoroethylene is polymerized further in the presence of a nonionic surfactant (2).

5. The method according to claim 1,

wherein tetrafluoroethylene is polymerized further in the presence of a comonomer (3) having a monomer reactivity ratio of 0.1 to 8.

6. The method according to claim 5,

wherein the comonomer (3) is at least one selected from the group consisting of comonomers represented by the formulae (3a) to (3d):

CH₂═

CH—

Rf¹ 

 

(3a),

wherein Rf¹ represents a C1-C10 perfluoroalkyl group;

CF₂═

CF—

O—

Rf² 

 

(3b),

wherein Rf² represents a C1-C2 perfluoroalkyl group;

CF₂═

CF—

O—

(CF₂)_nCF═

CF₂ 

 

(3c),

wherein n represents 1 or 2;

7. The method according to claim 1,

wherein tetrafluoroethylene is polymerized further in the presence of a reactive emulsifier (4).

8. The method according to claim 7,

wherein the reactive emulsifier (4) is at least one selected from the group consisting of compounds represented by the formulae (4a) to (4e):

CF₂═

CF—

(CF₂)_n1—

Y³ 

 

(4a),

wherein n1 represents an integer of 1 to 10, Y³ represents —

SO₃M¹ or —

COOM¹, M¹ represents H, NH₄, or an alkali metal;

CF₂═

CF—

(CF₂C(CF₃)F)_n2—

Y³ 

 

(4b),

wherein n2 represents an integer of 1 to 5, and Y³ is as defined above;

CF₂═

CF—

O—

(CFX¹)_n3—

Y³ 

 

(4c),

wherein X¹ represents F or CF₃, n3 represents an integer of 1 to 10, and Y³ is as defined above;

CF₂═

CF—

O—

(CF₂CFX¹O)_n4—

CF₂CF₂—

Y³ 

 

(4d),

wherein n4 represents an integer of 1 to 10, and Y³ and X¹ are as defined above; and

CX²₂═

CFCF₂—

O—

(CF(CF₃)CF₂O)_n5—

CF(CF₃)—

Y³ 

 

(4e),

wherein X²s are the same as one another and represent F or H, n5 represents an integer of 0 or 1 to 10, and Y³ is as defined above.