Abstract: To provide a modified PTFE excellent in heat resistance. The modified polytetrafluoroethylene comprises a polymer having units based on tetrafluoroethylene and a polymer having units based on a fluorine-free monomer, wherein the endothermic amount ratio R calculated by a prescribed method is at least 0.65.

Abstract: A shaping material for a powder bed fusion method, including a powder of a fluororesin, wherein the fluororesin has a D50 of 30 ?m or more and 200 ?m or less, and the fluororesin has a D10 of 12 ?m or more.

Abstract: The present invention is directed to partially fluorinated copolymers and the production thereof. More specifically, the copolymers, which are preferably produced by a solution polymerization process, preferably have at least three units, the first unit selected from 2,3,3,3-tetrafluoropropene and 1,3,3,3-tetrafluoropropene, the second unit having a polymerized monomer selected from the vinyl esters and vinyl ethers, and the third unit having a polymerized monomer derived from a hydroxyl group-containing vinyl ether. The resulting copolymer is environmentally friendly, has favorable molecular weight characteristics, and may be shipped economically in high concentration.

Abstract: The invention pertains to a composition (C1) comprising: at least one (meth)acrylic modified VDF polymer [polymer (A)] comprising recurring units derived from comprising recurring units derived from vinylidene fluoride (VDF) monomer and at least one hydrophilic (meth)acrylic monomer (MA) of formula (I), wherein each of R1, R2, R3, equal or different from each other, is independently a hydrogen atom or a C1-C3 hydrocarbon group, and ROH is a hydrogen or a C1-C5 hydrocarbon moiety comprising at least one hydroxyl group; at least one inorganic UV blocker compound in an amount not exceeding 5% wt, with respect to the weight of polymer (A), to multilayer assemblies comprising one layer made from said composition (C1), to a method for manufacturing said multilayer assemblies and to the use of the same in different field of use, including protection of PV modules.

Abstract: This disclosure relates to a method of making a fluoropolymer object. The method may include providing a substrate including fluoropolymer comprising units derived from monomers M1, M2 and M3, wherein: M1 is a vinylidene fluoride; M2 is a monomer of formula (I): CX1X2?CX3X4, wherein each of X1, X2, X3 and X4 is independently selected from H, Cl and F, and wherein at least one of X1, X2, X3 and X4 is F; M3 is a monomer of formula (II): CY1Y2?CY3CF3, wherein each of Y1, Y2 and Y3 is independently selected from H, Cl, F, Br, I and alkyl groups comprising from 1 to 3 carbon atoms which are optionally partly or fully halogenated; and stretching the substrate.

Abstract: Disclosed are protective coating compositions having enhanced gloss retention properties formed by steps comprising: (i) providing one or more fluorocopolymers by copolymerization of (1) one or more hydrofluoroolefin monomer(s) selected from the group consisting of hydrofluoroethylenes, hydrofluoropropenes, hydrofluorobutenes, hydrofluoropentenes and combinations of these, (2) one or more vinyl ester monomer(s), and (3) one or more vinyl ether monomer(s), wherein at least a portion of said vinyl ether monomer is a hydroxyl group-containing vinyl ether monomer, wherein the copolymer preferably has a number average molecular weight of greater than about 10,000; (ii) providing a VOC containing carrier for said one or more fluorocopolymers; and (iii) providing a stabilizing agent comprising: a) a radical scavenger and b) an absorber of UV light; and (iv) combining said one or more fluorocopolymers with said carrier and said stabilizing agent to produce a polymeric coating composition.

Abstract: The invention relates to a method for manufacturing a cross-linked polymer comprising reacting at least one polymer having at least one —SO2X group, with X being F or Cl, a basic compound, and certain salts including a ring-quaternized pyridinium-type nitrogen, and possessing at least two groups in ortho or para position thereto comprising reactive hydrogen atoms; cross-linking has been proven to proceed effectively, delivering cross-linked polymers possessing improved chemical resistance and mechanical performances.

Abstract: The present invention relates to a composition that includes a PTFE powder, a surfactant, at least one of a polyalkylsiloxane, a polyalkylarylsiloxane, a fatty acid, a fatty acid salt, an alkyl- or alkyl aryl-fatty acid ester, a phosphate trialkyl or triaryl ester, an alkyl fluorosilicone, a C12-C40 alkane, a vegetable oil or a paraffin wax, and a salt. The present invention also relates to aqueous system that includes such composition and to uses thereof.

Abstract: A binder and an electrode mixture for a secondary battery. The binder contains a fluorine-containing polymer containing a polymerized unit based on vinylidene fluoride, a polymerized unit based on tetrafluoroethylene, and a polymerized unit based on a monomer (2-2) represented by the following formula (2-2): R5R6C?CR7R8CO2Y1??(2-2) wherein R5, R6, and R7 are each independently a hydrogen atom or a C1-C8 hydrocarbon group; R8 is a C1-C8 hydrocarbon group; and Y1 is an inorganic cation and/or an organic cation.

Abstract: Provided are fibers that have excellent mechanical properties such as strength and that do not result in the filament breakage during a manufacturing process. The fibers are vinylidene fluoride resin fibers including a plurality of vinylidene fluoride resin filaments, and having a degree of crystal orientation of 80% or more as determined on the basis of X-ray diffraction from the azimuth angle intensity distribution curve of 2?=20.8±1°, and a crystal size of 12 nm or less.

Abstract: A fluororubber composition comprising 10 to 50 parts by weight of wollastonite and 0.5 to 10 parts by weight of organic peroxide based on 100 parts by weight of peroxide-crosslinkable fluororubber, the wollastonite being needle-like or fibrous wollastonite having an average fiber diameter of 5 ?m or less and an average fiber length of 40 to 80 ?m, and the wollastonite being surface-treated with an amino silane coupling agent or an epoxy silane coupling agent. The fluororubber composition that can be suitably used as, for example, a molding material for normal/reverse rotation oil seals that allow continuous excellent sealing of fluid in the operation of normal and reverse rotation.

Abstract: Methods are provided to efficiently produce butyl rubber via a slurry polymerization process. The process comprises providing at least two monomers, wherein at least one monomer is an isoolefin and at least one monomer is a multiolefin. The monomers are combined with an initiator and an organic diluent comprising 40-60 volume % of methyl chloride and 40-60 volume % of 1,1,1, 2-tetrafluoroethane and polymerized.

Abstract: This vinyl polymer powder, which contains a vinyl polymer, has a glass transition temperature of at least 0° C. (where if there are a plurality of glass transition points, all of the glass transition temperatures are at least 0° C.), has no greater than 350 ppm of the total content of magnesium ions, calcium ions, aluminum ions, barium ions, and zinc ions, has no greater than 100 ppm of the content of ammonium ions, has an acid number of no greater than 2.5 mgKOH/g, and has a bulk density of 0.10-0.60 g/cm3.

Abstract: A method for avoiding the entrapment of air bubbles (5) in a lens forming material, in particular in a low viscosity lens forming material, in an ophthalmic lens manufacturing process using mold halves (2; 3) each having a lens forming surface (21; 31) comprises electrostatically charging a predetermined portion of the lens forming surface (21; 31) of the mold half (2; 3) prior to the predetermined portion of the lens forming surface (21; 31) coming into contact with the lens forming material (4).

Abstract: Described herein is a composition comprising an aqueous polymerization reaction product of fluorinated monomers and wherein the polymerization is initiated (i) in the absence of a fluorinated emulsifier and whereby no fluorinated emulsifier is added during polymerization or (ii) in the presence of an fluorinated emulsifier selected from: [Rf—O-L-COO-]i Xi+ (I) wherein L represents a linear or branched, non-fluorinated, partially fluorinated, or fully fluorinated alkylene group, Rf represents a linear or branched partially or fully fluorinated aliphatic group or a linear or branched partially or fully fluorinated aliphatic group interrupted with at least one oxygen atom, Xi+ represents a cation having the valence i and i is 1, 2 or 3; wherein the reaction product and/or the resulting aqueous phase are substantially free of di- and tri-alkylamines and substantially free of low molecular weight fluoroorganic compounds and methods thereof.

Abstract: A process for producing a fluorinated olefin/vinyl alcohol copolymer, which comprises emulsion polymerizing a fluorinated olefin and a vinyl ether in the presence of an aqueous medium and an emulsifier and converting the repeating units based on the vinyl ether to the vinyl alcohol.

Abstract: Presently described are articles, such as optical displays and protective films, comprising a (e.g. light transmissive) substrate having a surface layer comprising the reaction product of a mixture comprising a non-fluorinated binder precursor (e.g. of a hardcoat composition) and at least one polymerizable perfluoropolyether polymer. The resulting cured surface layer can advantageously exhibit low lint attraction in combination with low surface energy. Also described are one-step and two-step methods of synthesizing perfluoropolyether polymers having polymerizable ethylenically unsaturated groups.

Abstract: Apparatus for determining a thickness of a wall of a pipe, featuring a signal processing module configured to respond to signaling containing information about traveling stress waves transmitted to and reflected back from a wall of a pipe by a sensor band that includes a series, ring or array having multiple transducers circumferentially arranged and mounted around, and attached to or clamped onto, an outside wall of the pipe; determine a profile of a thickness of the wall of the pipe corresponding to circumferential locations of the multiple transducers based on the signaling received from the sensor band, and the provides corresponding signaling containing information about the profile of the thickness of the wall of the pipe; and another module configured to receive the corresponding signaling and provide a visual indication of either data or a graph of the thickness of the wall of the pipe.

Abstract: Apparatus for determining a thickness of a wall of a pipe, featuring a signal processing module configured to respond to signaling containing information about traveling stress waves transmitted to and reflected back from a wall of a pipe by a sensor band that includes a series, ring or array having multiple transducers circumferentially arranged and mounted around, and attached to or clamped onto, an outside wall of the pipe; and determine a profile of a thickness of the wall of the pipe corresponding to circumferential locations of the multiple transducers based on the signaling received from the sensor band; and one or more orientation or rotation sensors, each responding to its orientation in relation to its displacement on the pipe and to provide an orientation signal containing information about the same.

Abstract: A fluorinated copolymer composition comprises ethylene/tetrafluoroethylene-containing copolymer and copper oxide. The ethylene/tetrafluoroethylene-containing copolymer comprises repeating units (A) based on ethylene, repeating units (B) based on tetrafluoroethylene and repeating units (C) based on another monomer, in a molar ratio of the repeating units (A) to the repeating units (B) of from 38/62 to 44/56, and in an amount of the repeating units (C) of from 0.1 to 2.6 mol % in all the repeating units of the ethylene/tetrafluoroethylene-containing copolymer. The content of the copper oxide is from 0.2 to 10 ppm based on the total weight of ethylene/tetrafluoroethylene-containing copolymer. The copper oxide has a BET surface area of from 5 to 30 m2/g. The volume flow rate of the fluorinated copolymer composition at 297° C. is from 15 to 150 g/10 min.

Abstract: The piezoelectric and barrier liner for a high-pressure storage vessel is made out of PVDF-TrFE copolymer and the amount of crystallinity in the liner material is over 30%, preferably 35% at least.

Abstract: A negative dead volume syringe comprising a body defining a chamber, a syringe tip disposed at a distal end of the chamber and having a tip passageway therethrough in open communication with the chamber, a rod extending from a first end within the chamber to a second end coupleable to a motor to produce bidirectional motion of the rod, and a plunger tip having a proximal portion coupled to the first end of the rod, a medial portion distally extending from said proximal portion and shaped to complement the tip passageway, and a tip extension distally extending from said medial portion and shaped to be received within a dead volume defined by a passageway of a valve coupleable to the syringe tip wherein the plunger tip ensures evacuation of fluid and air from the chamber, syringe tip, and dead volume of the valve upon distal displacement of the rod.

Abstract: The present invention relates to nanocones and nanomaterials. In one embodiment, the present invention provides a method of fabricating an array of nanostructures on a flexible film, comprising self-assembling a layer of particles on a film, and fabricating an array of nanostructures by etching and/or modifying the film. In another embodiment, the present invention provides a microarray comprising a nanomaterial comprising a film configured for an array of one or more nanocones.

Abstract: A method of producing a fluoropolymer by which a melt-processable fluoropolymer (A) having a specific unstable terminal group or groups (P) is subjected to melt-kneading in a kneader having a stabilization treatment zone to thereby produce a fluoro-polymer (B) resulting from conversion of the specific unstable terminal group or groups (P) to —CF2H. The specific unstable terminal group or groups (P) include alkoxycarbonyl groups, fluoroalkoxycarbonyl groups and/or carboxyl group quaternary nitrogen compound salts, the melt-kneading is carried out in the absence or presence of an alkali metal element or alkaline earth metal element, the content of the alkali metal element or alkaline earth metal element is not greater than 2 ppm of the composition under melt-kneading, and the melt-kneading in the stabilization treatment zone is carried out in the presence of water. A fluoro-polymerized material is also disclosed.

Abstract: A robotic electrostatic painting system includes a barrier formed from an electrical insulating material and disposed between adjacent reservoirs for holding a conductive paint used in an electrostatic painting operation. The barrier is shaped and dimensioned with a central plate and upper and lower flanges to block every straight line path between the reservoirs to electrostatically separate the reservoirs and prevent the formation of a ground path or short circuit when there is a voltage difference between the reservoirs. The electrostatic separation of the reservoirs further prevents deterioration of conductive components of the robotic electrostatic painting system.

Abstract: The invention concerns a method for preparing block copolymers, comprising a step of controlled free-radical copolymerisation of trifluoroethylene with at least one additional monomer, different from trifluoroethylene, in the presence of a chain transfer agent, said chain transfer agent being a xanthate compound, a trithiocarbonate compound or a monoiodide compound. The invention also concerns the block copolymers likely to be obtained by this method.

Abstract: A tetrafluoroethylene (TFE) copolymer film having a first endotherm between about 50° C. and about 300° C., a second endotherm between about 320° C. and about 350° C., and a third endotherm between about 350° C. and about 400° C. is provided. In exemplary embodiments, the third endotherm is approximately 380° C. In some embodiments, the second endotherm is between about 320° C. and about 330° C. or between about 330° C. and about 350° C. TFE copolymer films have a methane permeability less than about 20 ?g*micron/cm2/min. In addition, the dense articles have a void volume of less than about 20%. Methods for dense articles from core shell tetrafluoroethylene copolymers are also provided. The dense articles exhibit improved physical and mechanical properties such as adhesion and barrier properties.

Abstract: An object of the present invention it to provide a novel fluororesin that has excellent mechanical strength and chemical resistance, and very low permeability at high temperature. The fluorine resin a copolymer that includes copolymerized units derived from tetrafluoroethylene, vinylidene fluoride, and an ethylenically unsaturated monomer other than tetrafluoroethylene and vinylidene fluoride. The fluororesin has a storage modulus E?, as measured at 170° C. by a dynamic viscoelasticity analysis, in the range of 60 to 400 MPa.

Abstract: The present invention is directed to partially fluorinated copolymers and the production thereof. More specifically, the copolymers, which are preferably produced by a solution polymerization process, preferably have at least three units, the first unit selected from 2,3,3,3-tetrafluoropropene and 1,3,3,3-tetrafluoropropene, the second unit having a polymerized monomer selected from the vinyl esters and vinyl ethers, and the third unit having a polymerized monomer derived from a hydroxyl group-containing vinyl ether. The resulting copolymer is environmentally friendly, has favorable molecular weight characteristics, and may be shipped economically in high concentration.

Abstract: A tetrafluoroethylene/hexafluoropropylene copolymer has improved moldability in melt extrusion molding, especially with significant reduction of defects in high-speed extrusion coating of an electrical wire. The tetrafluoroethylene/hexafluoropropylene copolymer is obtained by polymerization of at least tetrafluoroethylene and hexafluoropropylene selected from the group consisting of tetrafluoroethylene, hexafluoropropylene and a third monomer without mixing with the resin which has the melting point with the difference of 20 degree C. and more from the melting point of the tetrafluoroethylene/hexafluoropropylene copolymer; and has a complex viscosity of from 2.0×I03 to 10.0×I03 Pa*s and a storage modulus of from 0.1 to 3.5 Pa*s in melt viscoelasticity measurement under the condition of atmosphere temperature of 310 degree C. and angular frequency of 0.01 radian/second. The tetrafluoroethylene/hexafluoropropylene copolymer can be used in an electrical wire as a coating on a conductive core.

Abstract: An object of the present invention it to provide a novel fluororesin that has excellent mechanical strength and chemical resistance, and very low permeability at high temperature. The fluorine resin a copolymer that includes copolymerized units derived from tetrafluoroethylene, vinylidene fluoride, and an ethylenically unsaturated monomer other than tetrafluoroethylene and vinylidene fluoride. The fluororesin has a storage modulus E?, as measured at 170° C. by a dynamic viscoelasticity analysis, in the range of 60 to 400 MPa.

Abstract: Use in LAN cable applications, as materials for the coating of the primary cable and for the external jacket, of TFE thermoprocessable perfluoropolymers comprising perfluoroalkylvinylethers in the following amounts, expressed as percent by weight on the total of the monomers: a) 0-5.5% of perfluoromethylvinylether (PMVE); b) 0.4-4.5% of perfluoroethylvinylether (PEVE) and/or perfluoropropylvinylether (PPVE); when a) is present, then a)+b) ranges from 1.5% to 5.5% by weight on the total of the monomers; optionally c) 0-6% of hexafluoropropene (HFP); the TFE amount being the complement to 100% by weight.

Abstract: The present disclosure describes fluoropolymers having long chain branches and methods of making these fluoropolymers. These fluoropolymers may have improved melt processing properties. Shaped articles containing these fluoropolymers are also provided.

Abstract: A process is described comprising polymerizing at least one unsaturated monomer (e.g., fluorine substituted alkene monomer) in the presence of an azide radical initiator and a solvent, under reaction conditions and for a time sufficient to polymerize the at least one unsaturated monomer to form a polymer. The present disclosure provides a method for the synthesis of polymers with 100% azide chain end functionality, for living/controlled radical polymerization of unsaturated monomers (e.g., fluorine substituted alkene monomers) and for the synthesis of complex polymer architectures, using azide click reactions.

Abstract: To provide a binder for a storage battery device whereby favorable adhesion is obtainable and swelling by an electrolytic solution can favorably be suppressed. A binder for a storage battery device, which is made of a fluorinated copolymer comprising structural units (A), structural units (B) and structural units (C), wherein the molar ratio of the structural units (C) to the total of all the structural units excluding the structural units (C) is from 0.01/100 to 3/100: structural units (A): structural units derived from a monomer selected from the group consisting of tetrafluoroethylene, hexafluoropropylene, vinylidene fluoride and chlorotrifluoroethylene; structural units (B): structural units derived from ethylene or propylene; and structural units (C): structural units derived from a C5-30 organic compound having at least two double bonds and at least one of the double bonds being a double bond of a vinyl ether group or a double bond of a vinyl ester group.

Abstract: An object of the present invention is to provide a method for producing a fluoropolymer which produces a large number of particles with a small particle size using a specific non-fluorous compound having surfactant ability. The method for producing a fluoropolymer includes aqueous dispersion polymerization of a monomer including at least one fluoroolefin in the presence of a compound represented by the formula: CH2?CHCH2—O—(C?O)CHXCH2COO(CH2)nCH3 (in the formula, X is H or SO3Y wherein Y is NH4 or an alkaline metal; and n is an integer of 0 to 19.

Abstract: Provided is a material that can be easily biaxially oriented, homogeneously stretched even with a high draw ratio, and formed into a PTFE porous membrane with low pressure loss. The present invention relates to a polytetrafluoroethylene mixture comprising: a fibrillable modified polytetrafluoroethylene; and a fibrillable polytetrafluoroethylene homopolymer, the polytetrafluoroethylene homopolymer having strength at break of 25 N or higher.

Abstract: A binder, including a fluoropolymer, the fluoropolymer including a polymerization unit based on vinylidene fluoride and a polymerization unit based on a monomer having an amide group represented by —CO—NRR? (R and R? are the same as or different from each other and each represent a hydrogen atom or an alkyl group optionally having a substituent group) or an amide bond represented by —CO—NR?— (R? represents a hydrogen atom, an alkyl group optionally having a substituent group, or a phenyl group optionally having a substituent group) and having a solution viscosity of 10 to 20,000 mPa·s. Also disclosed is a positive electrode mixture and a negative electrode mixture containing the binder, a positive electrode, a negative electrode and a lithium ion secondary cell.

Abstract: The present invention relates to the polymerization and copolymerization of monomers in the presence of fluorinated propylene solvents. More particularly, the present invention relates to the use of polymerization mediums suitable to polymerize one or more monomers to form polymers and/or copolymers, with a tetrafluoropolypropylene being used as a solvent or diluent for the one or more monomers.

Abstract: To provide a fluorinated elastic copolymer which is excellent in crosslinking reactivity and extrusion moldability and which is curable to obtain a rubber excellent in permanent compression set resistance, base resistance and oil resistance and particularly suitable as a covering material for electric wires. A fluorinated elastic copolymer obtained by copolymerizing tetrafluoroethylene, propylene and optionally another monomer, wherein the molar ratio (a)/(b) of repeating units (a) derived from tetrafluoroethylene to repeating units (b) derived from propylene in the fluorinated elastic copolymer is from 60/40 to 75/25, and repeating units (c) derived from said another monomer is from 0 to 10 mol % in the fluorinated elastic copolymer.

Abstract: To provide a binder for a storage battery device, whereby good adhesion in an electrode and flexibility are obtainable, and it is possible to realize good charge and discharge characteristics when used for a secondary battery. A binder for a storage battery device, which is made of a fluorinated copolymer comprising structural units (a) derived from tetrafluoroethylene and structural units (b) derived from propylene, wherein the molar ratio (a)/(b) is from 40/60 to 50/50, and the total of the structural units (a) and (b) is at least 90 mol % in all structural units.

Abstract: A catalyst composition comprising a cation and an anion of the formula Anq?Qpm+, wherein m, n, p, and q are positive integers, wherein m*p=n*q, wherein Qm+is an organo onium, and Aq?is an anion, provided that at least one Aq?is selected from the formula (I) wherein each R independently is H, halo, alkyl, aryl, aralkyl, or cycloalkyl, and which also may be halogenated, fluorinated, or perfluorinated, wherein two or more of R and R? groups may together form a ring, wherein each R group independently may contain one or more heteroatom(s), wherein R? can be the same as R, with the proviso that R? cannot be halo, and wherein the catalyst composition is essentially free of hydrocarbon containing alcohol. Also provided are a fluoropolymer composition including this curative, a method of making a fluoropolymer, and fluoropolymer articles containing curable or cured fluoropolymer compositions.

Abstract: To provide a copolymer which can impart sufficient dynamic water repellency, after air-drying water repellency and friction durability to a surface of an article, and which has low impact on the environment, a method for producing the same, a water repellent composition and an article excellent in dynamic water repellency, after air-drying water repellency and friction durability.

Abstract: Amorphous hydrofluoroolefin telomers are prepared by a free-radical polymerization process conducted at high temperature and pressure in the presence of non-monomeric chain transfer agent.

Abstract: To provide a process for producing a PTFE fine powder having a high bulk density, whereby the concentration of non-coagulated PTFE in coagulation wastewater is low. Tetrafluoroethylene is emulsion-polymerized in the presence of an aqueous medium, at least one fluorinated emulsifier selected from the group consisting of a C4-7 fluorinated carboxylic acid having from 1 to 4 etheric oxygen atoms in its main chain, and its salts, and a radical polymerization initiator, to produce a polytetrafluoroethylene emulsion; the obtained polytetrafluoroethylene emulsion is adjusted to a polytetrafluoroethylene concentration of from 10 to 25 mass %, followed by coagulation and stirring at a coagulation temperature of from 5 to 18° C. to separate a wet-state polytetrafluoroethylene fine powder; and the obtained wet-state polytetrafluoroethylene fine powder is dried to produce a polytetrafluoroethylene fine powder.

Abstract: A mold release film, which is adapted to be disposed on the cavity surface of a mold to form a resin-encapsulated portion by encapsulating a semiconductor element of a semiconductor device with a curable encapsulation resin, has a tensile modulus of elasticity of from 10 to 24 MPa at 132° C. as measured in accordance with JIS K 7127, and a peak peel resistance of at most 0.8 N/25 mm.

Abstract: The present invention provides a polytetrafluoroethylene powder having moldability/processability as well as electrical characteristics in microwave bands. The present invention is a modified polytetrafluoroethylene powder which has (1) a dielectric loss tangent at 12 GHz of not higher than 2.0×10?4 and (2) a cylinder extrusion pressure of not higher than 45 MPa at a reduction ratio of 1600.

Abstract: A vinylidene fluoride homopolymer represented by the formula (4): CF3-(A1)-I??(4) wherein A1 represents a structural unit of vinylidene fluoride homopolymer which includes crystal form I alone or as main component and has a number average degree of polymerization of 5 to 12.

Abstract: A fluorinated elastic copolymer which has iodine atoms, bromine atoms, or both iodine and bromine atoms, at its molecular terminals and which includes repeating units (a) based on tetrafluoroethylene, repeating units (b) based on a fluorinated monomer having one polymerizable unsaturated bond (provided that tetrafluoroethylene is excluded), and repeating units (c) based on a fluorinated monomer having at least two polymerizable unsaturated bonds, wherein the ratio (molar ratio) of the repeating units (a) to the repeating units (b) is (a)/(b)=40/60 to 90/10, and the proportion of the repeating units (c) based on the total amount of the repeating units (a) and the repeating units (b) is from 0.01 to 1 mol %.

Abstract: Provided is a material that can be easily biaxially oriented, homogeneously stretched even with a high draw ratio, and formed into a polytetrafluoroethylene porous membrane with low pressure loss. The present invention relates to a polytetrafluoroethylene mixture comprising: a modified polytetrafluoroethylene; and a fibrillable polytetrafluoroethylene homopolymer, the modified polytetrafluoroethylene having an extrusion pressure to a cylinder, at a reduction ratio of 1600, of 70 MPa or higher.