The present invention provides a flexible pipe having excellent blister resistance in a high-temperature and high-pressure environment even though including a thick resin pipe. The flexible pipe includes a resin pipe having a thickness of greater than 5 mm. The resin pipe is formed from a resin having a CO.sub.2 permeability coefficient P(CO.sub.2) of 20×10.sup.−9 cm.sup.3.Math.cm/cm.sup.2.Math.s.Math.cmHg or lower at 150° C., a CH.sub.4 permeability coefficient P(CH.sub.4) of 10×10.sup.−9 cm.sup.3.Math.cm/cm.sup.2.Math.s.Math.cmHg or lower at 150° C., a ratio D(CO.sub.2)/S(CO.sub.2) between a CO.sub.2 diffusion coefficient D(CO.sub.2) and a CO.sub.2 solubility coefficient S(CO.sub.2) of 3×10.sup.−5 Pa.Math.m.sup.2/s or higher at 150° C., and a ratio D(CH.sub.4)/S(CH.sub.4) between a CH.sub.4 diffusion coefficient D(CH.sub.4) and a CH.sub.4 solubility coefficient S(CH.sub.4) of higher than 15×10.sup.−5 Pa.Math.m.sup.2/s at 150° C.

A composition comprising at least one fluoropolymer and at least one solvent, wherein the solvent comprises a branched, partially fluorinated ether and wherein the partially fluorinated ether corresponds to the formula:
C.sub.pF.sub.2p+1—O—C.sub.qH.sub.2q+1
wherein q is an integer from 1 to and 5 and p is an integer from 5 to 11; and wherein the fluoropolymer is a copolymer comprising at least 90% by weight (based on the total weight of the polymer, which is 100% by weight) of units derived from tetrafluoroethene (TFE) and one or more perfluorinated alkyl ethers selected from ethers corresponding to the general formula
R.sub.f—O—(CF.sub.2).sub.n—CF═CF.sub.2
wherein n is 1 in which case the ether is an allyl ether, or 0 in which case the ether is a vinyl ether and R.sub.f represents a perfluoroalkyl residue which may be interrupted once or more than once by an oxygen atom. Also provided are methods of preparing the compositions and methods for coating substrate with the compositions.

Particles of a fluorine-containing polymer used as a transparent solid material in an artificial transparent frozen soil is provided. The fluorine-containing polymer is poly[4,5-difluoro-2,2bis(trifluoromethyl)-1,3-dioxole-co-tetrafluoroethylene], with a refractive index of 1.31 and a density of 2.1-2.3 g/cm.sup.3. The particles have a particle diameter of 0.25-2.0 mm or a particle diameter 0.074 mm, and have irregular shapes. When particles of the fluorine-containing polymer are used as a transparent solid material for preparing a transparent frozen soil, the prepared transparent frozen soil has high transparency, low price, no toxicity and no harm, good similarity with the properties of a natural frozen soil body, can substitute natural frozen soil, is used for simulating complicated geological conditions, and is effectively used in model tests in geotechnical engineering.

Described herein is a method of making a curable perfluoroelastomer, wherein the curable perfluoroelastomer comprises particles of a semi crystalline fluoropolymer, wherein the semi crystalline fluoropolymer is a TFE copolymer comprising no more than 1 wt % of at least one additional fluorinated monomer. The method comprises: (a) obtaining an amorphous perfluoropolymer and the particles of the semi crystalline fluoropolymer; and (c) dry blending the amorphous perfluoropolymer and the particles to form a curable perfluoroelastomer.

A method for producing a fluoropolymer by solution polymerization or dispersion polymerization, the method including: in the presence of an initiator, a chain transfer agent, and a solvent, (i) homopolymerizing tetrafluoroethylene; or (ii) randomly copolymerizing tetrafluoroethylene and at least one of a monomer represented by the following formula (1) or a monomer represented by the following formula (2). The chain transfer agent includes at least one selected from dithioester compounds, dithiocarbamate compounds, trithiocarbonate compounds and xanthate compounds. The fluoropolymer contains 50 to 100 mol % of a polymerized unit based on the tetrafluoroethylene. The formula (1): CF.sub.2═CR.sup.1R.sup.2 wherein R.sup.1 and R.sup.2 are as defined herein, the formula (2): CH.sub.2═CR.sup.3R.sup.4 wherein R.sup.3 and R.sup.4 are as defined herein.

A method for producing a fluorosulfonyl group-containing compound to obtain a compound represented by the following formula 5 from a compound represented by the following formula 1 as a starting material and a method for producing a fluorosulfonyl group-containing monomer in which the fluorosulfonyl group-containing compound is used: ##STR00001##
wherein R.sup.1 and R.sup.2 are a C.sub.1-3 alkylene group, and R.sup.F1 and R.sup.F2 are a C.sub.1-3 perfluoroalkylene group.

A method for producing a fluorosulfonyl group-containing compound to obtain a compound represented by the following formula 5 from a compound represented by the following formula 1 as a starting material and a method for producing a fluorosulfonyl group-containing monomer in which the fluorosulfonyl group-containing compound is used: ##STR00001##
wherein R.sup.1 and R.sup.2 are a C.sub.1-3 alkylene group, and R.sup.F1 and R.sup.F2 are a C.sub.1-3 perfluoroalkylene group.

The invention pertains to a fluoropolymer composition comprising certain tetrafluoroethylene/perfluoromethyvinylether copolymers having well-defined TFE/MVE monomer composition and possessing low molecular weight and a white pigment, to the use of this latter for manufacturing shaped articles, and to shaped articles therefrom, including components of light emitting apparatuses, e.g. LED assemblies.

Provided herein is a curable fluoroelastomer composition including at least one fluoroelastomer comprising copolymerized units of a nitrile group-containing cure site monomer; a cure system comprising at least two different dihydrazides; and optionally at least one additive. Further provided are pre-forms comprising the curable composition, methods of curing the fluoroelastomer composition, compositions that are the product of curing the curable fluoroelastomer composition, and articles comprising the cured fluoroelastomer composition.

Described herein is a perfluoropolymer and compositions therefrom. The perfluoropolymer is derived from: (a) no more than 88 mol % tetrafluoroethylene monomer; and (b) a complementary amount of a perfluoro (cycloaliphatic methyl vinyl ether) monomer, and has substantially no melting point.