Abstract: An optical material comprising a thermal resisting fluoroalkylmethacrylate copolymer which essentially consists of(a) fluorine-containing methacrylate monomer unit of the formula ##STR1## wherein R.sub.f.sup.1 represents a fluoroalkyl group having 1 to 3 carbon atoms and(b) a fluorine-containing acrylate monomer unit of the formula ##STR2## wherein R.sub.1 and R.sub.2 are the same or different and represents a hydrogen atom or a lower alkyl group and R.sub.f.sup.2 represents a fluoroalkyl group having 1 to 3 carbon atoms.

Abstract: A process for preparing a tetrafluoroethylene/fluoro(alkyl vinyl ether) copolymer comprising polymerizing tetrafluoroethylene and fluoro(alkyl vinyl ether) in an aqueous suspension system which comprises a mixed medium of water and a fluorohydrocarbon or a chlorofluorohydrocarbon in a volume ratio of from 1:1 to 10:1 at a temperature of from 0.degree. to 25.degree. C. in the presence of a polymerization initiator of the formula:[Cl(CF.sub.2).sub.n --COO].sub.2 (I)wherein n is an integer of 1 to 10, the copolymer obtained by the process having a small number of unstable terminal groups and excellent flex life.

Abstract: A process for preparing a trifluoromethylbenzonitrile derivative of the formula: ##STR1## wherein X is hydrogen, lower alkyl, halogenated lower alkyl, lower alkoxy, nitro, hydroxyl, amino, cyano, carboxyl or sulfon which comprises reacting trifluoromethylhalogenobenzene of the formula: ##STR2## wherein X is as defined above, and Y is halogen with copper (I) cyanide in a solvent selected from the group consisting of hexamethylphosphoric triamide, N-methylpyrrolidone and a mixture thereof in the presence of a catalyst selected from the group consisting of (A) bromine, (B) iodine, (C) a combination of bromine or iodine and metallic copper and (D) copper (II) bromide, by which process the compound (I) is prepared in a good yield, and by-products are produced in a lower yield than the conventional processes.

Abstract: A fluoroelastomer composition comprising a cross-linkable fluoroelastomer and/or a thermoplastic fluoroelastomer and carbon fiber having a low volume resistivity of 10.sup.-1 to 10.sup.13 ohm.cm.

Abstract: A fluoroelastomer composition comprising a fluoroelastomer and a thermoplastic fluoroelastomer, which has good roll retention and roll processability and a mixed compound of which has little self-adhesiveness.

Abstract: A fluorine-containing elastomeric copolymer which comprises units of at least one fluorovinyl ether of the formula: ##STR1## wherein X is C.sub.1 -C.sub.3 perfluoroalkyl, C.sub.1 -C.sub.3 .omega.-hydroperfluoroalkyl or C.sub.1 -C.sub.3 .omega.-chloroperfluoroalkyl, Y is hydrogen, chlorine, fluorine, trifluoromethyl, difluoromethyl or chlorodifluoromethyl and n is an integer of 1 to 4 and units of at least one other fluorine-containing monomer copolymerizable therewith, the content of the fluorovinyl ether units being 15 to 50 mol %, which has excellent resistance to low temperatures.

Abstract: A process for producing fluorine-containing organic compounds characterized in that fluorine-containing aliphatic iodides which comprise at least one selected from the group of R.sub.f I, R.sub.f ZnI and R.sub.f SnX.sub.2 I (where R.sub.f indicates a fluorine-containing aliphatic group; and X indicates halogen), or which comprise R.sub.f COOR' (where R.sub.f indicates a fluorine-containing aliphatic group; and R' indicates an aliphatic hydrocarbon group or aromatic hydrocarbon group) are reacted with organic compounds under ultrasonic wave action, whereby the R.sub.f group or the R.sub.f CO group is introduced into the said organic compounds.

Abstract: A fluoroalkyl silyl ketene acetal of the formula ##STR1## wherein R.sub.f is a fluoroalkyl group, and R and R' are the same or different and each is an alkyl group, which is prepared by reacting or fluorinated carboxylic acid of the formulaR.sub.f CH.sub.2 COOR'wherein R.sub.f and R' are respectively the same as defined above with a silylating agent represented by a formulaR.sub.3 SiOTfwherein Tf represents a trifluoromethane sulfonyl group and R is the same as defined above.

Abstract: A fluoroelastomer-containing non-tacky electrically conductive coating composition which comprises (a) a fluoroelastomer, (b) a fluororesin, (c) a coupling agent, (d) an electrically conducting material, (e) a liquid vehicle and optionally (f) an inorganic fibrous material, the weight ratio of the fluoroelastomer (a) and the fluororesin (b) being from 95:5 to 35:65, a coating film formed from which has electrical conductivity as well as the properties inherent to the fluoroelastomer.

Abstract: Fluorine-containing phenyl benzoate compounds which have the general formula: ##STR1## wherein R is a C.sub.1 -C.sub.12 perfluoroalkyl group, a C.sub.1 -C.sub.12 alkyl group, a C.sub.1 -C.sub.12 alkoxy group, a C.sub.2 -C.sub.13 alkanoyloxy group, a C.sub.2 -C.sub.13 alkoxycarbonyl group, a C.sub.2 -C.sub.13 alkoxycarbonyloxy group or a C.sub.2 -C.sub.13 alkyldioxycarbonyl group and X is a C.sub.1 -C.sub.12 alkyl group, a C.sub.1 -C.sub.12 alkoxy group, a cyano group, a trifluoromethyl group or a nitro group with the proviso that X is trifluoromethyl when R is other than perfluoroalkyl are useful as components of liquid crystals.

Abstract: In a heat exchanger for an air conditioning system including a plurality of heat exchanger tubes and a plurality of fins secured to outer surfaces of the heat transfer tubes, the fins are of a special constructional form, such as slitted fins having slits formed in flat or convoluted fins or spine fins, and the heat transfer tubes are each formed on its inner wall surface with spiral grooves or two systems of spiral grooves of large number. The heat transfer tubes define therein a refrigerant passage while the adjacent two fins define therebetween an air passage extending past the outer surfaces of the heat transfer tubes.

Abstract: These compounds are especially useful as intermediates to the corresponding thionophosphonic acid esters having insecticidal and acaricidal properties.

Abstract: 5-Fluorocytosine hydrofluoride of high purity is prepared by fluorinating cytosine with fluorine gas in the presence of hydrogen fluoride, followed by treatment of the resultant fluorinated product in the reaction mixture at a temperature higher than the fluorination temperature.

Abstract: A fluorine-containing compound of the formula: ##STR1## wherein Rf is a C.sub.3 -C.sub.21 fluorine-containing group; R is a hydrogen atom or a C.sub.1 -C.sub.4 acyl group; Q is an aliphatic or aromatic hydrocarbon group having not more than twenty-one carbon atoms; and n is an integer of 1 to 10 lowers the surface tensions of water and/or organic liquids and the interfacial tensions between them.

Abstract: Compositions using for working fluids and heat-transfer media comprising 81 to 100 parts by weight of 2,2,3,3,3-pentafluoropropanol and 0 to 19 parts by weight of water.

Abstract: N,N-dialkyl-3-oxo-3-alkyl-1,2-difluoropropenylamine expressed by the following general formula: ##STR1## where R.sup.1, R.sup.2 and R.sup.3 are same or different alkyl groups.

Abstract: Working fluids for use with the Rankine cycle comprising 5 to 50% by weight of tetrafluoromethane, 40 to 95% by weight of trifluoromethane and 0 to 10% by weight of monochlorodifluoromethane.

Abstract: A fluorine-containing surface active composition capable of reducing the surface tension of water and the interfacial tension between water and oil, which comprises (A) at least one cationic, non-ionic or ampho-ionic surfactant showing a surface tension of not more than 25 dyne/cm when determined on a 0.01 to 1.0% by weight aqueous solution and having at least one fluorine-containing group comprising not less than 6 carbon atoms, of which each carbon atom bears at least one fluorine atom, and (B) at least one of surfactants of the formula: ##STR1## wherein R is a substituted or unsubstituted aliphatic group of 4 to 20 carbon atoms or a substituted or unsubstituted aromatic hydrocarbon group of 6 to 20 carbon atoms, R.sup.1, R.sup.2 and R.sup.

Abstract: A multi-vane type compressor formed with vane back pressure spaces having introduced thereinto a suction gas pressure in the suction and compression strokes and a discharge gas pressure in the discharge stroke. The compressor includes supply grooves for introducing the discharge gas pressure into the vane back pressure spaces, which are each split into a trailing side portion and a leading side portion. Each leading side portion for coping with the terminating stage of the discharge stroke is exposed to the discharge gas pressure via a passageway offering large resistance to the flow of fluid, to throttle the gas forced out of the vane back pressure spaces as the vanes are forced into vane grooves to thereby raise the vane back pressure. This is conducive to prevention of the jumping action of the vanes, and wear of the tips of the vanes and to minimization of vibration and noise.

Abstract: A variable display hydraulic pump having at least one pilot plunger, an operating plunger for adjusting the displacement of variable control element, and a first and a second spool for controlling travels of the plungers towards the variable control element side so that a single pumping element may precisely, stably carry out the two pressure-two volume control of the pump.