Abstract: Powder including low molecular weight polytetrafluoroethylene having a melt viscosity of 1×102 to 7×105 Pa·s at 380° C., having a melt viscosity of 1×102 to 7×105 Pa·s at 380° C., having an average particle size of 1.0 to 50 ?m, and containing 30 or more carboxyl groups at ends of the molecule chain per 106 carbon atoms in the main chain, wherein the powder is substantially free from C8-C14 perfluorocarboxylic acids and salts thereof.

Abstract: Powder including low molecular weight polytetrafluoroethylene having a melt viscosity of 1×102 to 7×105 Pa·s at 380° C., having a melt viscosity of 1×102 to 7×105 Pa·s at 380° C., having an average particle size of 1.0 to 50 ?m, and containing 30 or more carboxyl groups at ends of the molecule chain per 106 carbon atoms in the main chain, wherein the powder is substantially free from C8-C14 perfluorocarboxylic acids and salts thereof.

Abstract: Powder including low molecular weight polytetrafluoroethylene having a melt viscosity of 1×102 to 7×105 Pa·s at 380° C., having a melt viscosity of 1×102 to 7×105 Pa·s at 380° C., having an average particle size of 1.0 to 50 ?m, and containing 30 or more carboxyl groups at ends of the molecule chain per 106 carbon atoms in the main chain, wherein the powder is substantially free from C8-C14 perfluorocarboxylic acids and salts thereof.

Abstract: Powder including low molecular weight polytetrafluoroethylene having a melt viscosity of 1×102 to 7×105 Pa·s at 380° C., having a melt viscosity of 1×102 to 7×105 Pa·s at 380° C., having an average particle size of 1.0 to 50 ?m, and containing 30 or more carboxyl groups at ends of the molecule chain per 106 carbon atoms in the main chain, wherein the powder is substantially free from C8-C14 perfluorocarboxylic acids and salts thereof.

Abstract: The invention provides a production method for producing low molecular weight polytetrafluoroethylene enabling easy removal of most of C8-C14 perfluorocarboxylic acids and salts thereof, which are unfortunately generated by irradiation, from the low molecular weight polytetrafluoroethylene. The method for producing low molecular weight polytetrafluoroethylene includes: (1) irradiating polytetrafluoroethylene to provide low molecular weight polytetrafluoroethylene having a melt viscosity of 1×102 to 7×105 Pa·s at 380° C.; (2) pulverizing the low molecular weight polytetrafluoroethylene; and (3) heating the low molecular weight polytetrafluoroethylene pulverized in the step (2).

Abstract: Low molecular weight polytetrafluoroethylene powder having a complex viscosity of 1×102 to 7×105 Pa·s at 380° C., containing 5 or less carboxyl groups at ends of the molecule chain per 106 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.

Abstract: Low molecular weight polytetrafluoroethylene powder having a complex viscosity of 1×102 to 7×103 Pa·s at 380° C., containing 5 or less carboxyl groups at ends of the molecule chain per 106 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.

Abstract: 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 1×102 to 7×105 Pa·s at 380° C.

Abstract: The invention provides a production method for producing low molecular weight polytetrafluoroethylene enabling easy removal of most of C8-C14 perfluorocarboxylic acids and salts thereof, which are unfortunately generated by irradiation, from the low molecular weight polytetrafluoroethylene. The method for producing low molecular weight polytetrafluoroethylene includes: (1) irradiating polytetrafluoroethylene to provide low molecular weight polytetrafluoroethylene having a melt viscosity of 1×102 to 7×105 Pa·s at 380° C.; (2) pulverizing the low molecular weight polytetrafluoroethylene; and (3) heating the low molecular weight polytetrafluoroethylene pulverized in the step (2).

Abstract: The invention provides a method for producing low molecular weight polytetrafluoroethylene less likely to generate C8-C14 perfluorocarboxylic acids and salts thereof. The method for producing low molecular weight polytetrafluoroethylene 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 1×102 to 7×105 Pa·s at 380° C.

Abstract: In order to provide a welded structure of and welding method for two metallic parts fitted together at a tubular section in a high-pressure fuel supply pump, an electric current is supplied to any of the welding connection surfaces formed between a pump housing and cylinder in a high-pressure fuel supply pump, between the pump housing and an installation flange, between the pump housing and an intake or discharge joint, between the pump housing and a pulsation-absorbing damper cover, between the pump housing and a relief valve mechanism, and between the pump housing and an electromagnetically driven intake valve mechanism. The two sections are pressed against each other to generate, along the connection surface, a plastic flow not causing melting or fusion due to heat, and form a diffusion-weld region at the connection surface by using the plastic flow and the application of the pressure.

Abstract: Dissimilar metal welds including a buttering portion with a small variation in strength distribution in a plate thickness direction are formed by welding two parent materials having at least one of different compositions and different refining conditions through a buttering for alleviating mismatch between one of the different compositions and the different refining conditions of the two members and through a welded metal for joining one of the parent materials and the buttering. The buttering is formed of welding metals laminated in a plate thickness direction, and a dilution ratio of the buttering with the parent materials is 50% or less. The manufacturing method includes performing butt welding on a dummy material formed by increasing a groove depth by providing a member on a bottom side of a welding groove and on parent materials by using the buttering; and processing a groove within a welding metal formed of the buttering.

Abstract: An object of this invention is to provide such a welded structure of and welding method for two metallic parts fitted together at a tubular section in a high-pressure fuel supply pump, that enables rapid joining of both metallic parts by staking (press-fitting included), screw fastening, and/or laser welding, offers high welding strength and sufficient fluid sealability, and keeps the metallic materials free from thermal changes in composition.

Abstract: There is provided a lifting pole apparatus which can lift and lower a pole having such strength as to be capable of preventing cars from entering. The lifting pole apparatus comprises a cylindrical pole which is capable of lifting and lowering inside a housing case; a screw shaft hanging from a top portion of the pole inwardly; a stay disposed upright on a bottom portion of the housing case, and housed in the pole; a driving gear rotatably supported on the stay, and having a screw portion on a through hole disposed at a center axis thereof, the screw portion being threadably mounted on the screw shaft; at least two motors disposed on the stay for rotating the driving gear; and an electro-magnetic brake disposed on the stay for activating the brake on the rotation of the driving gear.

Abstract: There is provided a lifting pole apparatus which can lift and lower a pole having such strength as to be capable of preventing cars from entering. The lifting pole apparatus comprises a cylindrical pole which is capable of lifting and lowering inside a housing case; a screw shaft hanging from a top portion of the pole inwardly; a stay disposed upright on a bottom portion of the housing case, and housed in the pole; a driving gear rotatably supported on the stay, and having a screw portion on a through hole disposed at a center axis thereof, the screw portion being threadably mounted on the screw shaft; at least two motors disposed on the stay for rotating the driving gear; and an electro-magnetic brake disposed on the stay for activating the brake on the rotation of the driving gear.

Abstract: The method for concentrating a fluoropolymer in a fluoropolymer aqueous dispersion includes a step for preparing a fluoropolymer aqueous dispersion, and a step for filtering the fluoropolymer aqueous dispersion in a polymer membrane. The polymer membrane oscillates during the filtration. The method for concentrating a water-soluble, fluorine-containing emulsifier in an aqueous solution containing the water-soluble, fluorine-containing emulsifier includes a step for preparing an aqueous solution containing a water-soluble, fluorine-containing emulsifier, and a step for filtering the aqueous containing the water-soluble, fluorine-containing emulsifier in a polymer membrane. The polymer membrane oscillates during both the filtration steps.

Abstract: In the preparation of a modified polytetrafluoroethylene fine powder by polymerizing tetrafluoroethylene in an aqueous medium in the presence of a water soluble fluorine-containing dispersant, a fluoroalkyl vinyl ether is added to a reaction system at latest at a start of a reaction and a copolymerization reaction of the fluoroalkyl vinyl ether with tetrafluoroethylene is initiated, and a chain transfer agent is added to the reaction system after at least 80% of tetrafluoroethylene to be polymerized is consumed. The obtained modified polytetrafluoroethylene fine powder has good molding properties, in particular, extrusion properties, and high heat resistance.

Abstract: A modified polytetrafluoroethylene fine powder containing agglomerates of colloidal particles with an average particle size of from 0.05 to 0.5 &mgr;m which comprise a copolymer of tetrafluoroethylene and an olefin-monomer represented by X(CF2)nOCF═CF2 in which X is a hydrogen atom, a fluorine atom or a chlorine atom, and n is an integer of 1 to 6, and/or C3F7(OCF2CF2CF2)m[OCF(CF3)CF2]pOCF═CF2 in which m and p are independently an integer of 0 to 4, provided that the sum of m and p is not 0 (zero), a content of the olefin monomer being from 0.02 to 0.3 wt. %, wherein the copolymer has a molecular weight distribution Mw/Mn of from 1.5 to 4.5 and a standard specific gravity of from 2.135 to 2.175. This modified polytetrafluoroethylene has good paste extrudability, and provides molded articles having good mechanical properties, in particular, pressure resistance.

Abstract: A polytetrafluoroethylene fine powder excellent in powder flowability which comprises fine particles (the primary particle) having a mean particle diameter of 0.05 to 1 &mgr;m, an apparent density of 0.52 to 0.70 g/ml, a standard specific gravity (SSG) of 2.14 to 2.23, and a secondary mean particle diameter of 100 to 1000 &mgr;m, antidripping agent using the above polytetrafluoroethylene fine powder, flame resistive resin composition containing this powder, and composition for inhibiting dust characteristics containing this powder.

Abstract: To provide the method for concentrating an aqueous dispersion of fluorine-containing polymer particles containing a surfactant, which is applicable to a fluorine-containing polymer such as PTFE being easily fibrilated and assures low energy, low cost and short term concentration only by using various kinds of surfactants in a small amount. The method for concentrating an aqueous dispersion of fluorine-containing polymer particles containing the surfactant by feeding the aqueous dispersion of fluorine-containing polymer particles containing the surfactant in an amount of 2.0 to 8.0% by weight based on a solid content of the fluorine-containing polymer to a micro filtration membrane having a pore size of 0.01 to 1 .mu.m with aqueous dispersion feeding means which does not substantially generate shearing force and then removing an aqueous medium containing the surfactant from the aqueous dispersion.