Abstract: A fluorine-containing elastomer having excellent low temperature resistance and oil resistance comprises ethylene units (E) and fluorovinyl ether units (FV) having the formula CF.sub.2 .dbd.CFOX (X represents a C.sub.1 -C.sub.9 perfluoroalkyl group which can have one or more ether bond) at a molar ratio of (E) to (FV) of 95:5 to 30:70 and at a total content of (E) and (FV) of at least 70 mole %.

Abstract: A composite membrane for gas separation having a three-layered structure comprising:(A) a porous polymer supporting membrane layer having a cross-sectional oxygen permeation flux of at least 5 m.sup.3 /m.sup.2.hr.atm (STP) and having an asymmetric porous structure such that the average pore diameter at one surface is from 5 to 500 .ANG. and the average pore diameter at the other surface is greater than that at said one surface;(B) a polyorganosiloxane layer having a thickness of from 300 .ANG. to 5 .mu.m; and(C) a thin layer having a thickness of from 100 to 5000 .ANG. and made of a polymer containing monomer units of at least one monomer selected from the group consisting of fluoroolefin monomers and pivalate ##STR1## group-containing monomers, being soluble in an organic solvent and having an O.sub.2 /N.sub.2 permeability coefficient ratio of at least 3.

Abstract: A copolymer for an fluorine-containing elastomer having excellent low temperature resistance and alcohol resistance comprises vinylidene fluoride units and fluorovinyl ether units having the formula CF.sub.2 =CFOX (X represents a C.sub.3 -C.sub.9 perfluoroalkyl group which has ether bond having 1-3 oxygen atom) at a molar ratio of vinylidene fluoride units to fluorovinyl ether units of 95:5 to 50:50 and at a total content of the units of at least 80 mole %.

Abstract: A fluorinated cation exchange membrane is formed using a copolymer of a fluorovinyl ether (I) having the formulaCF.sub.2 .dbd.CF--O--CF.sub.2 --CFXOCF.sub.2).sub.l (CFX').sub.m (CF OCFX").sub.n Awherein l is 0 to 3; m is 2 to 6; n is 0 to 4 and one of l and n is not zero and l+m+n.gtoreq.3; X, X' and X" are the same or different and each respectively represent --F or --CF.sub.3 ; A represents --CN,--COF, --COOH, --COOR,--COOM or --CONR.sub.2 R.sub.3 ; R.sub.1 represents a C.sub.1-10 alkyl group; and M represents an alkali metal or a quaternary ammonium salt; and a fluorinated olefin (II), or a hydrolyzed copolymer thereof. The fluorinated cation exchange membrane is used for production of a halogen and an alkali metal hydroxide by electrolysis of an alkali metal hydride.

Abstract: A fluorinated acid fluoride having an ester group which has the formula ##STR1## wherein A,p, q and R are defined below is produced by reacting a diacid fluoride having the formula ##STR2## wherein A represents a C.sub.1 -C.sub.10 bifunctional perfluoro group; p represents 0 or 1; q represents an integer of 1 to 8 with an alcohol having the formula ROH wherein R represents an organic group.

Abstract: A process for producing a carboxyl group-containing fluoropolymer comprises reacting a hydroxyl group-containing fluoropolymer in an organic solvent with a dibasic acid anhydride represented by the general formula ##STR1## where R represents a bifunctional organic group, to convert at least a part of hydroxyl groups into ester groups represented by the general formula ##STR2## where R is as defined above.

Abstract: A permselective element for gas separation comprises a permselective layer composed of an organic polymer having -OCOC(CH.sub.3).sub.3 groups in its side chains. The permselective element is useful for the separation of oxygen/nitrogen.

Abstract: An anticorrosive coating process comprises:(i) a step of applying on a substrate a zinc-rich paint or an epoxy resin primer coating, followed by air-drying,(ii) a step of applying thereon an intermediate synthetic resin coating, followed by air-drying, and(iii) a step of applying thereon a top coating comprising (a) a fluorine-containing copolymer composed of from 40 to 60 molar % of a fluoroolefin, from 5 to 45 molar % of cyclohexylvinyl ether, from 5 to 45 molar % of an alkylvinyl ether, from 3 to 15 molar % of a hydroxyalkylvinyl ether and from 0 to 30 molar % of other comonomer and (b) a polyisocyanate, followed by air-drying.

Abstract: An anticorrosive coating process comprises:(i) a step of forming a primer coating layer by applying on a substrate an oil-type anticorrosive coating or an alkyd resin-type anticorrosive coating as a primer coating, followed by air-drying,(ii) a step of forming a binder coating layer by applying on the primer coating layer a phenol-modified alkyd resin-type coating containing a flaky pigment, followed by air-drying, and(iii) a step of forming a top coating layer by applying on the binder layer a top coating comprising (a) a fluorine-containing copolymer composed of from 40 to 60 molar % of a fluoroolefin, from 5 to 45 molar % of cyclohexylvinyl ether, from 5 to 45 molar % of an alkylvinyl ether, from 3 to 15 molar % of a hydroxyalkylvinyl ether and from 0 to 30 molar % of other comonomer and (b) a polyisocyanate, followed by air-drying.

Abstract: A copolymer for a fluorine-containing elastomer having excellent low temperature resistance and alcohol resistance comprises vinylidene fluoride units and fluorovinyl ether units having the formula CF.sub.2 =CFOX (X represents a C.sub.3 -C.sub.9 perfluoroalkyl group which has ether bond having 1-3 oxygen atom) at a molar ratio of vinylidene fluoride units to fluorovinyl ether units of 95:5 to 50:50 and at a total content of the units of at least 80 mole %.

Abstract: An antithrombogenic material is composed of a fluorine-containing block polymer obtained by the polyaddition or polycondensation of a prepolymer with a chain extender, said prepolymer being a diisocyanate prepolymer represented by the formulaOCN--CH.sub.2 RfCH.sub.2 NHCOO--A--CONH].sub.m CH.sub.2 RfCH.sub.2 NCO (I)wherein Rf is a perfluoroalkylene or perfluoroxyalkylene group having from 1 to 20 carbon atoms and containing from 0 to 10 ether linkages, A is a divalent organic group containing an oxygen atom in its main chain and m is from 1 to 3, or a dicarbamate prepolymer obtained by reacting the diisocyanate prepolymer with a lower alcohol.

Abstract: Perfluorosuccinyl fluoride is produced by coupling accompanied by dehalogenation of a difluorohaloacetyl fluoride having the formulaXCF.sub.2 COFwherein X represents I, Br or Cl by reacting with a trapping agent of a halogen at a temperature ranging from 100.degree. to 500.degree. C.

Abstract: A fluorine-containing elastomer having excellent low temperature resistance and oil resistance comprises ethylene units (E) and fluorovinyl ether units (FV) having the formula CF.sub.2 .dbd.CFOX (X represents a C.sub.1 -C.sub.9 perfluoroalkyl group which can have one or more ether bond) at a molar ratio of (E) to (FV) of 95:5 to 30:70 and at a total content of (E) and (FV) of at least 70 mole %.

Abstract: A difluorohaloacetyl fluoride is produced by (a) producing an intermediate having a group of the formulaXCF.sub.2 CFYOSO.sub.2.sup.-wherein X is I or Br, Y is F, Cl, Br or I; by reacting a polyfluoroethylene of the formulaCF.sub.2 .dbd.CFYwith a reagent obtained by mixing sulfur trioxide with a halogen selected from iodine and bromine; and (b) decomposing said intermediate into said product.

Abstract: A curable fluorocopolymer comprises 40 to 60 mol % of fluoroolefin units, 5 to 45 mol % of cyclohexyl vinyl ether units, 5 to 45 mol % of alkyl vinyl ether units and 3 to 15 mol % of hydroxyalkyl vinyl ether units and has an inherent viscosity of 0.05 to 2.0 dl/g. in tetrahydrofuran at 30.degree. C.

Abstract: A fluorovinyl ether having the formulaXRfCF.sub.2 OCF.dbd.CF.sub.2 (I)wherein X represents --H, --Cl, --Br, --F, --CO.sub.2 R, --CONRR', --SO.sub.2 F, ##STR1## or --COF and R represents a C.sub.1 -C.sub.10 alkyl group; R' represents --H or a C.sub.1 -C.sub.10 alkyl group; Rf represents a C.sub.1 -C.sub.20 bifunctional perfluoro-containing group is produced by reacting an iodine-containing ether having the formulaXRfCF.sub.2 OCF.sub.2 CF.sub.2 I (II)in the presence of a catalytic component selected from the group consisting of Mg, Cu, Zn, Zn-Cu, Zn-Cd, Zn-Pd, Zn-Hg, Sn, Sb, organomagnesium compounds and organolithium compounds.

Abstract: A cation exchange membrane of a fluorinated polymer for an electrolysis comprises a structure of a copolymer of a fluorinated olefin and a fluorovinyl compound having the formulaCF.sub.2 .dbd.CX--(OCF.sub.2 CFY).sub.l (O).sub.m (CFY').sub.n COOMwherein X represents --F or --CF.sub.3 ; Y and Y' respectively represents --F or a C.sub.1 -C.sub.10 perfluoroalkyl group; l is 0 to 3; m is 0 or 1; n is 0 to 12 and M represents hydrogen atom or an alkali metal atom; and a modified surface layer of said cation exchange membrane in an anode side which has --SO.sub.3 M groups formed by converting --COOM groups.

Abstract: A process for producing difluoroiodoacetyl fluoride comprises a step of producing an intermediate having a group of ICF.sub.2 CF.sub.2 OSO.sub.2 -- by reacting 1,2-diiodotetrafluoroethane with an oxidizing acid having S(VI) atom and a step of decomposing said intermediate into said product.

Abstract: Propylene and tetrafluoroethylene are copolymerized at the low temperature of 0.degree.-50.degree. C. in an aqueous medium in the presence of a specific redox catalyst system. The specific redox catalyst system comprises (1) a water soluble inorganic persulfate, (2) a water soluble thiosulfate or bisulfite and (3) a water soluble iron salt, and preferably further comprises a reducing sugar and a water soluble pyrophosphate. The propylene-tetrafluoroethylene copolymer having high molecular weight and low Mooney viscosity can be prepared at high copolymerization reaction rates.

Abstract: A macromolecular adsorbent is suitable for recovering heavy metal ions such as uranium ions from a dilute solution such as sea water and is a polymer having pendant groups having the formula ##STR1## wherein R.sup.1 represent a C.sub.1 -C.sub.8 divalent organic group; R.sup.2 and R.sup.3 respectively represents a C.sub.1 -C.sub.5 divalent organic group; p, q, r and l respectively represent 0 or 1; R.sub.f represents a C.sub.1 -C.sub.10 divalent perfluoro group; X.sup.1 and X.sup.2 respectively represent hydroxyl group or a hydroxyl convertible group or atom.