Fluorine-containing polymer powder, film, and method for producing fluorine-containing polymer powder

Patent metadata

Field	Value
Publication number	US-10023748-B2
Application number	US-201214236134-A
Country	US
Kind code	B2
Filing date	Aug 29, 2012
Priority date	Aug 29, 2011
Publication date	Jul 17, 2018
Grant date	Jul 17, 2018

Abstract

The present invention aims to provide a fluorine-containing polymer powder that is environmentally less harmful and forms a sufficiently smooth film without impairing the properties of the fluorine-containing polymers. The present invention relates to a fluorine-containing polymer powder including a fluorine-containing polymer prepared by suspension polymerization, which contains less than 0.1 ppm of a fluorine-containing surfactant and has an average particle size of not less than 1 μm and less than 100 μm and a bulk density of 0.90 to 1.50 g/cm3.

First claim

The invention claimed is:

1. A method for producing a fluorine-containing polymer powder comprising a fluorine-containing polymer prepared by suspension polymerization,
wherein the fluorine-containing polymer powder contains less than 0.1 ppm of a fluorine-containing surfactant and has an average particle size of at least 100 μm but at most 1000 μm and a bulk density of 1.00 to 1.50 g/cm 3 ,
wherein the fluorine-containing polymer is at least one selected from the group consisting of tetrafluoroethylene-perfluoro(alkyl vinyl ether) copolymers, tetrafluoroethylene-hexafluoropropylene copolymers, and tetrafluoroethylene-ethylene copolymers,
wherein the tetrafluoroethylene-perfluoro (alkyl vinyl ether) copolymer is a copolymer in which the molar ratio of tetrafluoroethylene (TFE) unit and perfluoro (alkyl vinyl ether)(PAVE) unit (TFE unit/PAVE unit) is 80/20 to 98/2, and
(i) consists of TFE unit and PAVE unit, or
(ii) comprises TFE unit, PAVE unit and a monomer unit derived from a monomer copolymerizable with TFE and PAVE wherein the total of the TFE unit and PAVE unit is 90 to 99.9 mol % and the monomer unit derived from a monomer copolymerizable with TFE and PAVE is 0.1 to 10 mol %,
wherein tetrafluoroethylene-hexafluoropropylene copolymer is a copolymer in which the molar ratio of TFE unit and hexafluoropropylene (HFP) unit (TFE unit/HFP unit) is 80/20 to 97/3, and
(iii) consists of TFE unit and HFP unit, or
(iv) comprises TFE unit, HFP unit and a monomer unit derived from a monomer copolymerizable with TFE and HFP wherein the total of the TFE unit and HFP unit is 90 to 99.9 mol % and the monomer unit derived from a monomer copolymerizable with TFE and HFP is 0.1 to 10 mol %, and
wherein the fluorine-containing polymer is a melt-processible fluorine resin,
the method comprising:
polymerizing fluorine-containing ethylenic monomers by suspension polymerization to prepare fluorine-containing polymer powder;
optionally densifying the polymer powder with a roll mill under the conditions that enable the specific gravity of the resulting powder to reach at least 90% of the absolute specific gravity, to prepare ground powder;
putting the polymer powder or ground powder into an attrition mill;
processing the polymer powder or ground powder into a desired shape; and
collecting the fluorine-containing polymer powder from the attrition mill.

Assignees

• Nakatani Yasukazu
• Miyatani Toshio
• SHIGENAI Fumiko
• Kinoshita Toshiyuki
• Daikin Ind Ltd

Inventors

• Nakatani Yasukazu
• Miyatani Toshio
• SHIGENAI Fumiko
• Kinoshita Toshiyuki

Classifications

• C08F214/262

  with fluorinated vinyl ethers · CPC title

• C08J3/12

  Powdering or granulating · CPC title

• C08F14/18 Primary

  Monomers containing fluorine · CPC title

• C08J2327/12

  containing fluorine atoms · CPC title

• C08F214/265

  with non-fluorinated comonomers · CPC title