Daikin Industries, Ltd.

Asahi Kasei Kabushiki Kaisha

Asahi Kasei E-materials Corporation

Masaharu Nakazawa

Masahiro Kondo

Tadashi Ino

Takashi Yoshimura

Noriyuki Shinoki

Naoki Sakamoto

Naoto Miyake

Takahiko Murai

Tadaharu Isaka

Kazuhiro Ohtsuka

Kohei Kita

Yuki Yotsumoto

The invention provides a powder that is easily redispersible in a liquid medium such as water. The powder contains a fluoropolymer. The fluoropolymer contains at least one group A selected from the group consisting of &#x2014;SOY, &#x2014;COOR, &#x2014;SOX, &#x2014;SONR, and &#x2014;COOX, wherein Y is a halogen atom; R is a C1-C4 alkyl group; X is Mor NR, where M is a hydrogen atom or an L-valent metal, the L-valent metal being a metal in group 1, group 2, group 4, group 8, group 11, group 12, or group 13 of the periodic table; and Rs are each individually a hydrogen atom or a C1-C4 alkyl group. The powder exhibits a dispersion of 50% or higher. The dispersion is calculated by filtering a composition obtainable by mixing the powder with water through a mesh having an opening of 20 &#x3bc;m.

Fluoropolymer powder and method for producing same

A method for producing an electrolyte emulsion, the method including: Step (1) in which an ethylenic fluoromonomer and a fluorovinyl compound having an SOZgroup, wherein Zis a halogen element, are copolymerized at a polymerization temperature of 0&#xb0; C. or higher and 40&#xb0; C. or lower to provide a precursor emulsion containing a fluoropolymer electrolyte precursor; and Step (2) in which a basic reactive liquid is added to the precursor emulsion and the fluoropolymer electrolyte precursor is chemically treated, whereby an electrolyte emulsion with a fluoropolymer electrolyte dispersed therein is provided, wherein the electrolyte emulsion has an equivalent weight (EW) of 250 or more and 700 or less.

Electrolyte emulsion and process for producing same

The present invention provides a fluoropolymer electrolyte material which has improved processability and which is easily produced. The electrolyte emulsion of the present invention comprises an aqueous medium and a fluoropolymer electrolyte dispersed in the aqueous medium. The fluoropolymer electrolyte has a monomer unit having an SOZ group (Z is an alkali metal, an alkaline-earth metal, hydrogen, or NRRRR, and R, R, R, and Reach are individually a C1-C3 alkyl group or hydrogen). The fluoropolymer electrolyte has an equivalent weight (EW) of 250 or more and 700 or less and a proton conductivity at 110&#xb0; C. and relative humidity 50% RH of 0.10 S/cm or higher. The fluoropolymer electrolyte is a spherical particulate substance having an average particle size of 10 to 500 nm. The fluoropolymer electrolyte has a ratio (the number of SOF groups)/(the number of SOZ groups) of 0 to 0.01.

The present invention provides an electrolyte having high conductivity even under high-temperature low-humidification conditions (e.g. at a temperature of 100 to 120&#xb0; C. and a humidity of 20 to 50% RH) and thereby makes it possible to realize a higher performance fuel cell. The present invention is a fluoropolymer electrolyte having an equivalent weight (EW) of not less than 250 but not more than 700 and a proton conductivity of not lower than 0.10 S/cm as measured at a temperature of 110&#xb0; C. and a relative humidity of 50% RH and comprising a COOZ group- or SOZ group-containing monomer unit, wherein Z represents an alkali metal, an alkaline earth metal, hydrogen atom or NRRRRin which R, R, Rand Reach independently represents an alkyl group containing 1 to 3 carbon atoms or hydrogen atom.

Polyelectrolyte and process for producing the polyelectrolyte

The invention provides a technique enabling the separation and recovery of an unreacted fluoromonomer from an aqueous fluoropolymer dispersion obtained by emulsion polymerization, without using any extraction solvent, and enabling the prevention of a hydrolysis of &#x2014;SOF and a like sulfonic acid precursor functional group convertible to sulfonic acid group. Thus, the invention provides a recovering method fluoromonomer having a sulfonic acid precursor functional group convertible to a sulfonic acid group and remaining unreacted from an aqueous fluoropolymer dispersion obtained by emulsion polymerization of the fluoromonomer, wherein the unreacted fluoromonomer is recovered from the aqueous fluoropolymer dispersion by evaporation, wherein the aqueous fluoropolymer dispersion has an acidic pH.

Growing community of inventors

Osaka, Japan

Masaharu Nakazawa