Polytetrafluoroethylene aqueous dispersion

Patent metadata

Field	Value
Publication number	US-9976022-B2
Application number	US-201515316031-A
Country	US
Kind code	B2
Filing date	Jun 4, 2015
Priority date	Jun 4, 2014
Publication date	May 22, 2018
Grant date	May 22, 2018

Abstract

The present invention provides a polytetrafluoroethylene aqueous dispersion containing high-molecular-weight, significantly small polytetrafluoroethylene particles and having excellent dispersion stability. The present invention relates to an aqueous dispersion containing polytetrafluoroethylene particles containing a tetrafluoroethylene unit alone or a tetrafluoroethylene unit and a modifying monomer unit based on a modifying monomer copolymerizable with the tetrafluoroethylene. The polytetrafluoroethylene particles have a volume average particle size of not smaller than 0.1 nm but smaller than 20 nm, a melt flow rate of not lower than 0 g/10 min but lower than 80 g/10 min determined at 380° C. and 5 kg load, a melting point of 324° C. to 360° C., and an initial pyrolysis temperature of not lower than 400° C.

First claim

The invention claimed is:

1. A polytetrafluoroethylene aqueous dispersion comprising:
polytetrafluoroethylene particles containing a tetrafluoroethylene unit alone or a tetrafluoroethylene unit and a modifying monomer unit based on said modifying monomer copolymerizable with the tetrafluoroethylene,
the polytetrafluoroethylene particles having a volume average particle size of not smaller than 0.1 nm but smaller than 20 nm, a melt flow rate of not lower than 0 g/10 min but lower than 80 g/10 min determined at 380° C. and 5 kg load, a melting point of 324° C. to 360° C., and an initial pyrolysis temperature of not lower than 400° C.

2. The polytetrafluoroethylene aqueous dispersion according to claim 1 , further comprising a fluorosurfactant in an amount corresponding to 4,600 to 500,000 ppm of the aqueous dispersion.

3. The polytetrafluoroethylene aqueous dispersion according to claim 1 , further comprising at least one selected from the group consisting of a fluorine-containing compound represented by the following formula (1):
X—(CF 2 ) m1 —Y  (1)

wherein X is H or F; m1 is an integer of 3 to 5; and Y is —SO 3 M, —OSO 3 M, SO 3 R, —OSO 3 R, —COOM, —PO 3 M 2 , or —OPO 3 M 2 , where M is H, NH 4 , or an alkali metal and R is a C1-C12 alkyl group; and a perfluoropolyether carboxylic acid represented by the formula (III):
Rf 1 —O—(CF(CF 3 )CF 2 O) n3 CF(CF 3 )COOM  (III)

wherein Rf 1 is a C1-C5 perfluoroalkyl group; n3 is an integer of 0 to 3; and M is defined as mentioned above.

4. The polytetrafluoroethylene aqueous dispersion according to claim 1 , which is free from a fluorine-containing compound represented by the following formula (2):
X—(CF 2 ) m2 —Y  (2)

wherein X is H or F; m2 is an integer of 6 or greater; and Y is —SO 3 M, —OSO 3 M, —SO 3 R, —OSO 3 R, —COOM, —PO 3 M 2 , or —OPO 3 M 2 , where M is H, NH 4 , or an alkali metal and R is a C1-C12 alkyl group.

Assignees

• Daikin Ind Ltd

Inventors

• Nanba Yoshinori
• Fukami Dai
• YAMABE Takuya
• Kato Taketo
• Ono Makoto
• Taira Takahiro
• Yoshida Hirotoshi
• Yamanaka Taku

Classifications

• C08L2201/54

  Aqueous solutions or dispersions · CPC title

• C08L27/18 Primary

  Homopolymers or copolymers or tetrafluoroethene · CPC title

• C08F2/26 Primary

  anionic · CPC title

• C08K5/095

  Carboxylic acids containing halogens · CPC title

• C08K5/5317

  Phosphonic compounds, e.g. R—P(:O)(OR')2 · CPC title