Daikin Industries, Ltd.

Daiken Industries, Ltd.

Satoshi Komatsu

Satoshi Koyama

Yoshiyuki Hiraga

Takehide Tsuda

Tomohisa Noda

Hiroyuki Imanishi

Takashi Shibanuma

Yoshinori Tanaka

Yukio Homoto

Toshikazu Yoshimura

Masayuki Namimatsu

Tetsuya Higuchi

Takeo Matsumoto

Hideya Saito

Nobuyoshi Iwashita

Yutaka Ueta

Satoshi Tokuno

Katsuhide Otani

Kunitada Tanaka

Yoshiki Maruya

Yasuhiro Utsumi

Akihiro Nakashima

To a fluorine-containing polymer, 0.1 to 10% of a compound having an alkali metal or an alkaline earth metal in terms of the number of atoms of the alkali metal or the alkaline earth metal based on the total number of the above terminal groups, 0.1 to 10% of ammonia in terms of the number of ammonia molecules based on the total number of the above terminal groups, or 0.1 to 10% of a compound having an ammonium group in terms of the number of the ammonium groups based on the total number of the above terminal groups is added, and heated at a temperature of at least 200&#xb0; C. in an atmosphere containing moisture. By this process, unstable terminal groups such as terminal carboxylic acid groups and coloration caused by such terminal groups are effectively removed from the fluorine-containing polymer, and furthermore unstable bonds in the backbones can be removed. The obtained fluorine-containing polymer contains 1.0&#xd7;10spins/g or less of unpaired electrons on the carbon atoms in terms of a spin density measured with electron spin resonance at a temperature of 10K.

Stabilized fluorine-containing polymer and method for stabilizing fluorine-containing polymer

A vulcanizable fluorine-containing elastomer composition having excellent stability in molding and kneading property, from which a vulcanized article having a small compression set can be produced in a short period of time. The vulcanizable fluorine-containing elastomer composition comprises a vulcanization agent, a vulcanization aid and a fluorine-containing elastomer having C&#x2014;H bond in its polymer chain, and an optimum vulcanization time T(min) of the composition and a compression set CS (%) of the vulcanized article satisfy the following equations (I) and (II):

Vulcanizable flouroelastomer composition

After a melt-processable fluorine-containing copolymer is heated and molten, the copolymer is reheatd in a closed apparatus under a non-static condition at a temperature of, for example, 130&#xb0; C. to the melting point of the fluorine-containing polymer, whereby a content of volatile materials in the copolymer is reduced to 30% or less of an initial content of volatile materials. Thereby, the content of volatile materials in the melt-processable fluorine-containing copolymer, which has been once molten, can be effectively decreased without using a large apparatus while avoiding the contamination of the copolymer with foreign particles.

Method for stabilizing fluorocopolymers

A melt-processable fluorine-containing polymer is melt kneaded with a kneader which has a residence time of at least 10 minutes, a usable volume ratio (usable space in a container/space in a container) of larger than 0.3, and a power factor K of less than 8000, the power factor K being represented by the formula: K&equals;Pv/&mgr;/n in which Pv is a power requirement per unit volume (W/m ), &mgr; is a melt viscosity (Pa.s), and n is a rotation speed (rps), to effectively remove terminal groups and bonds in the backbones, which are unstable during melt kneading, from the melt-processable fluorine-containing polymer, and obtain a colorless fluorine-containing polymer.

Method for stabilizing fluorine-containing polymer

A process for preparing a fluorine-containing elastomeric copolymer, a vulcanizing agent and a vulcanization accelerator, said process comprising the step of coagulating the copolymer from an aqueous dispersion of the fluorine-containing elastomeric copolymer and drying the resulting coagulate of the copolymer while kneading, wherein a mixture of mutually soluble components consisting of the vulcanizing agent and the vulcanization accelerator is added to the coagulate, can give a fluororubber composition having stable vulcanization physical properties, wherein the vulcanizing agent and the vulcanization accelerator are homogeneously dispersed in the fluororubber.

Process for producing elastic fluorocopolymer composition

To a fluorine-containing polymer, 0.1 to 10% of a compound comprising an alkali metal or an alkaline earth metal in terms of the number of atoms of the alkali metal or the alkaline earth metal based on the total number of the above terminal groups, 0.1 to 10% of ammonia in terms of the number of ammonia molecules based on the total number of the above terminal groups, or 0.1 to 10% of a compound having an ammonium group in terms of the number of the ammonium groups based on the total number of the above terminal groups is added, and heated at a temperature of at least 2000C in an atmosphere containing moisture. By this process, unstable terminal groups such as terminal carboxylic acid groups and coloration caused by such terminal groups are effectively removed from the fluorine-containing polymer, and furthermore unstable bonds in the backbones can be removed. The obtained fluorine-containing polymer contains 1.0&times;10 spins/g or less of unpaired electrons on the carbon atoms in terms of a spin density measured with spin resonance at a temperature of 10K.

Stabilized fluorine-containing polymer and method for stabilizing fluorine containing polymer

A process for preparing a fluoropolymer by polymerizing one or more radically polymerizable monomers comprising at least one fluoroolefin monomer in the presence of a radical polymerization initiator and as case demands, an inactive fluorocarbon and chain transfer agent in a reaction field where at least one of components forming the reaction field is in a supercritical state. According to the preparation process, generation of unstable end groups of the polymer, a decrease in a purity and complicated post-treatment can be eliminated.

Process for producing fluoropolymer

Hydrogen fluoride is effectively removed from a mixture of hydrogen fluoride, dichloromethane, chlorofluoromethane and/or difluoromethane by distilling the mixture so that two-component azeotropic mixtures of hydrogen fluoride and dichloromethane, hydrogen fluoride and chlorofluoromethane and hydrogen fluoride and difluoromethane are removed, or by liquid-separating the mixture into an upper liquid phase rich in hydrogen fluoride and a lower liquid phase not rich in hydrogen fluoride before each liquid phase is distilled as described above.

Process for removal of hydrogen fluoride

Method of stabilizing fluorine-containing polymer

A process for preparing a fluoropolymer by the batchwise polymerization of a monomer mixture containing tetrafluoroethylene, in which, after the initiation of a reaction, the monomers are reacted under conditions such that the monomer mixture is supplemented to a polymerization system in an amount more than the amount of the monomers consumed and simultaneously the excessive unreacted monomers are discharged from the polymerization system to maintain the monomer composition in the polymerization system substantially the same as that of the composition of the monomer mixture initially charged, and the monomer mixture supplemented to the polymerization system contains a compound suppressing the autoexplosion of the monomers.

Process for preparing fluoropolymer

Coagulated particles having a low water content are separated and recovered from an emulsified dispersion of fluorine-containing polymer particles. A solid-liquid separation method comprising: a step for adding a coagulant in an emulsified dispersion of fluorine-containing polymer particles to coagulate the fluorine-containing polymer particles with stirring and obtain a slurry of coagulated particles, a step for filtrating the slurry, and a step for pressing the obtained cake. It is preferable to continuously carry out the filtration step and pressing step with a filter press or a belt press. Also a washing step may be provided after the filtration step.

Solid-liquid separation method of fluorine-containing polymer particles

A production method in which reaction processes are divided into two regions comprising one reaction region where mainly perchloroethylene is made to react with HF in a vapor phase in the presence of a catalyst and the other reaction region where HCFC-123 (CF,CHCl,) and/or HCFC-124 (CF,CFHCl) is made to react with HF in a vapor phase in the presence of a catalyst, the former region being kept at a higher pressure and the latter region at a lower pressure during the reaction procedure. By this method it is possible to keep the conversion of perchloroethylene at a high level while securing the life of a catalyst, and it is also possible to raise the selectivity of HFC-125. This is a method of producing HFC-125 in which the content of CFC-115 is lowered to not more than 15 vol % of the total amount of HFC-125 and CFC-115, and then CFC-115 is made to react with hydrogen in the presence of a catalyst. By this method, reaction conditions can be lightened and the absolute amount of by-products also decreased, and the effective purification of HFC-125 can be realized.

Method of producing 1,1,1,2,2-pentafluoroethane a method of producing 2,-2,-diohloro-1,1,1-trifluorethane and a method of purifying 1,1,1,2 pentafluoroethane

A polymerization process, in which when at least one of fluorine-containing olefin monomers in gaseous phase or supercritical phase or a monomer mixture of the fluorine-containing olefin monomer and other monomer copolymerizable therewith is subjected to batch polymerization in an aqueous medium while being diffused to the aqueous medium, a diffusing amount of the monomer or monomer mixture to the aqueous medium is not less than 80% of the theoretical consumption of the monomer or monomer mixture when polymerized at the theoretical polymerization rate. According to the present invention, a polymerization rate is determined by the polymerization reaction but not by the diffusion of monomer gas, and thus higher polymerization rate can be achieved.

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Settsu, Japan

Satoshi Komatsu