Daikin Industries, Ltd.

Chie Sawauchi

Nobuhiko Tsuda

Tetsuo Shimizu

Yasuhiko Sawada

Makoto Ono

Taketo Kato

Akinori Yamamoto

Hiroyuki Sato

Hisako Nakamura

Seiji Takubo

Takuji Kume

Wade Martin Simpson

It is an object of the present invention to provide polytetrafluoroethylene suitable for forming a porous polytetrafluoroethylene film using a high water-soluble surfactant with high volatility. Polytetrafluoroethylene has non-melt-secondary-processability, standard specific gravity of 2.160 or less, an average primary particle size of 150 nm or more, stress relaxation time of 500 seconds or more, and break strength of 29.7 N or more. The polytetrafluoroethylene is obtainable by emulsion polymerization of tetrafluoroethylene in the presence of a fluorinated surfactant with Log POW of 3.4 or less.

Polytetrafluoroethylene and method for producing same

The present invention provides an aqueous fluororesin dispersion comprising a melt-processable fluororesin which is low in fluorinated surfactant concentration and excellent in dispersion stability even when the concentration of the melt-processable fluororesin is high. The present invention is related to an aqueous fluororesin dispersion comprising a melt-processable fluororesin particle dispersed in an aqueous medium, wherein a concentration of the melt-processable fluororesin is 55 to 75% by mass relative to the aqueous fluororesin dispersion, and a fluorinated surfactant content in the aqueous fluororesin dispersion is not higher than a level corresponding to 100 ppm of the melt-processable fluororesin.

Aqueous fluororesin dispersion and method for producing the same

The present invention provides an aqueous fluoropolymer dispersion having good mechanical characteristics and storage stability and containing substantially no fluorinated surfactant. The present invention is related to an aqueous fluoropolymer dispersion comprising a dispersed fluoropolymer particle with an average primary particle diameter of 50 to 400 nm, a surface layer of the dispersed fluoropolymer particle being obtained by emulsion polymerization of a monomer composition consisting of 99.999 to 98 mole percent of tetrafluoroethylene and 0.001 to 2 mole percent of a modifier monomer, a fluorinated surfactant content being not higher than 50 ppm, a fluoropolymer content being 20 to 75% by mass, and a nonfluorinated nonionic surfactant content being 2 to 15% by mass relative to 100% by mass of the fluoropolymer.

Aqueous fluorine-containing polymer dispersion

An object of the present invention is to provide an aqueous fluoropolymer dispersion inhibited from viscosity rising and excellent in mechanical stability in spite of a low fluorinated surfactant concentration. The invention provides an aqueous fluoropolymer dispersion comprising particles of a fluoropolymer as dispersed in an aqueous medium wherein a fluorinated surfactant (A) having a molecular weight lower than 1000 amounts to not higher than 100 ppm of the mass of the fluoropolymer, the aqueous fluoropolymer dispersion containing an anionic surfactant (B) other than the fluorinated surfactant (A) as well as a water-soluble polymer (C).

Aqueous fluoropolymer dispersion

A process for producing an aqueous fluoropolymer dispersion which includes adding a specific compound to a to-be-treated aqueous fluoropolymer dispersion containing a particle of fluoropolymer dispersed therein, the to-be-treated aqueous fluoropolymer dispersion containing a fluorinated surfactant (A) with a molecular weight lower than 1000 in an amount of 100 ppm or less of the fluoropolymer and the specific compound being (1) a sulfosuccinic acid alkyl ester or a salt thereof, or a sulfosuccinic acid fluoroalkyl ester or a salt thereof, (2) the fluorinated surfactant (A), (3) a fluorinated surfactant (B) with a molecular weight lower than 1000, differing from the fluorinated surfactant (A) and/or (4) an aliphatic carboxylic acid or a salt thereof, which compound is added in total amount of 10 to 5000 ppm of said fluoropolymer.

Aqueous fluoropolymer dispersion and process for producing the same

The present invention provides a method of producing a fluororesin aqueous dispersion which can produce a fluororesin aqueous dispersion low in fluorine-containing surfactant concentration and high in polytetrafluoroethylene concentration with high efficiency. The invention provides a method of producing a fluororesin aqueous dispersion which comprises subjecting a crude fluororesin aqueous dispersion comprising a polytetrafluoroethylene particle dispersed in an aqueous medium to treatment with an ion-exchange resin and to treatment for concentration by phase separation in the presence of an electrolyte and/or a fluorine-free anionic surfactant.

Method of producing a fluororesin aqueous dispersion

The present invention provides a method of producing a fluoropolymer aqueous dispersion by which the fluorine-containing emulsifier contained in the fluoropolymer aqueous dispersion as obtained after polymerization can be efficiently removed as well as a fluoropolymer aqueous dispersion low in fluorine-containing emulsifier concentration. The present invention is a method of producing a fluoropolymer aqueous dispersion which comprises carrying out a concentration treatment comprising a concentration operation of a pretreatment fluoropolymer aqueous dispersion, wherein the pretreatment fluoropolymer aqueous dispersion is obtained by carrying out a polymerization in an aqueous medium in the presence of a fluorine-containing surfactant (A), the fluorine-containing surfactant (A) is a fluorine-containing surfactant having an octanol/water partition coefficient of 1.5 to 3.5.

Process for producing aqueous fluoropolymer dispension and aqueous fluoropolymer dispersion

Process for producing aqueous fluoropolymer dispersion and aqueous fluoropolymer dispersion

The present invention relates to a method for producing carbonyl difluoride comprising a step of reacting trifluoromethane with oxygen or an oxygen-containing gas while heating.

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Settsu, Japan

Chie Sawauchi