The present invention discloses a modified polyvinyl chloride (PVC) paste resin and a method of making thereof. The PVC paste resin is prepared by mixing a PVC paste resin with polysiloxane (PBP), for example polyborodimethylsiloxanes.

Low molecular weight polytetrafluoroethylene powder having a complex viscosity of 110.sup.2 to 710.sup.3 Pa.Math.s at 380 C., containing 5 or less carboxyl groups at ends of the molecule chain per 10.sup.6 carbon atoms in the main chain, and being substantially free from C8-C14 perfluorocarboxylic acids and salts thereof. Also disclosed is a method for producing low molecular weight polytetrafluoroethylene.

To provide a method capable of producing, by means of mechanical pulverization, a resin powder having a high bulk density and an average particle size of at most 50 m from resin particles containing a fluorocopolymer as the main component and having a melting point of from 260 to 320 C., such as PFA. The method is to obtain a resin powder having an average particle size of from 0.02 to 50 m by subjecting resin particles (A) having an average particle size of at least 100 m to mechanical pulverization treatment. The resin particles (A) is made of a material (X) having a fluorocopolymer (X1) as the main component; and said fluorocopolymer (X1) has a unit (1) based on a monomer containing at least one type of functional group selected from the group consisting of a carbonyl group-containing group, a hydroxy group, an epoxy group and an isocyanate group, and a unit (2) based on tetrafluoroethylene, and has a melting point of from 260 to 320 C.

A fluororubber composition containing a ternary fluororubber polymer including vinylidene fluoride, perfluorovinyl ether and tetrafluoroethylene; a reaction product of silica-aluminum silicate with vinyl ethoxysilane; and hydrotalcite. The fluororubber composition does not substantially contain magnesium oxide and calcium hydroxide. The fluororubber composition contains 2 to 55 parts by weight of the reaction product of silica-aluminum silicate with vinyl ethoxysilane and 0.5 to 10 parts by weight of the hydrotalcite relative to 100 parts by weight of the ternary fluororubber polymer.

The present invention provides an electrolyte material which can form crack-resistant catalyst layers when used in membrane electrode assemblies and enables provision of fuel cells having good power generation characteristics, a membrane electrode assembly and a polymer electrolyte fuel cell. The electrolyte material of the present invention is made of a polymer having ion exchange groups comprising units based on tetrafluoroethylene, units having an ion exchange group and no cyclic ether structure, units having a cyclic ether structure and units based on a monomer having at least two polymerizable unsaturated bonds.

To provide methods for producing a liquid composition, a coating liquid for a catalyst layer and a membrane electrode assembly, capable of making cracking less likely to occur at the time of forming a solid polymer electrolyte membrane or a catalyst layer. A copolymer having a structural unit represented by [CF.sub.2CF{(OCF.sub.2CFX).sub.mO.sub.p(CF.sub.2).sub.nSO.sub.3H}] (wherein X: F or CF.sub.3, m: 1 to 3, p: 0 or 1, and n: an integer of 1 to 12) and a structural unit derived from tetrafluoroethylene, is dispersed in a medium containing water and a hydrocarbon-type alcohol (but not including a fluorinated solvent) to prepare a dispersion wherein the concentration of the copolymer is from 13 to 26 mass %, and the dispersion and a fluorinated solvent are mixed so that the sum of the concentration of the copolymer and the concentration of the fluorinated solvent becomes to be from 17 to 35 mass %, to prepare a liquid composition.

A method for producing low molecular weight polytetrafluoroethylene less likely to generate C8-C14 perfluorocarboxylic acids and salts thereof. The method includes: (1) feeding into an airtight container: polytetrafluoroethylene; at least one additive selected from the group consisting of hydrocarbons, chlorinated hydrocarbons, alcohols, and carboxylic acids other than C8-C14 perfluorocarboxylic acids; and at least one selected from the group consisting of inert gases other than the above additive and oxygen adsorbents; and (2) irradiating the polytetrafluoroethylene to provide low molecular weight polytetrafluoroethylene having a complex viscosity of 110.sup.2 to 710.sup.5 Pa.Math.s at 380 C.

A method of producing a heat-resistant chlorine-containing crosslinked resin formed body, formed from: Step (a) of melt-mixing, to a base resin containing a chlorinated polyethylene and a polyvinyl chloride and a plasticizer, an organic peroxide, an inorganic filler, and a silane coupling agent, at a specific ratio, at a temperature equal to or higher than a decomposition temperature of the organic peroxide; Step (b) of mixing a silane masterbatch obtained in Step (a) and a silanol condensation catalyst; and Step (c) of crosslinking by bringing a formed body obtained by Step (b) into contact with water; wherein, in Step (a), from 5 to 55 mass % of the plasticizer is contained in 100 mass % of the base resin to be used in the reaction with the silane coupling agent; the formed body produced therefrom; a silane masterbatch and a mixture thereof; and a heat resistant product.

To provide a modified polytetrafluoroethylene excellent in breaking strength. The modified polytetrafluoroethylene comprises a polymer having units based on tetrafluoroethylene and a polymer having units based on a monomer represented by formula (1), wherein the content of the units based on a monomer represented by formula (1) is from 10 to 500 mass ppm, to all units in the modified polytetrafluoroethylene, and the standard specific gravity is from 2.155 to 2.175,
CH.sub.2CR.sup.1-L-R.sup.2Formula (1):
wherein R.sup.1 represents a hydrogen atom or an alkyl group, L represents a single bond, COO*, OCO*, or O, * represents a bonding position to R.sup.2, and R.sup.2 represents a hydrogen atom, an alkyl group, or a nitrile group.

a composite material having (A) a base layer containing perfluoroalkoxy alkane and carbon fiber, (B) an intermediate layer and (C) a polytetrafluoroethylene cover layer, wherein the intermediate layer contains perfluoroalkoxy alkane is disclosed.