Nitto-denko Corporation

Japan Atomic Energy Agency

Hitachi Maxell, Limited

Toshimitsu Tachibana

Yozo Nagai

Soji Nishiyama

Masaru Yoshida

Masaharu Asano

Tetsuya Yamaki

Jinhua Chen

Masaaki Mori

Kenji Sato

Yasunari Maekawa

Yousuke Morita

Mitsuo Iimura

Shuuji Yano

Katsuya Kume

Hajime Yamamoto

Satoru Furuyama

Masakatsu Urairi

Hiroyuki Iida

Junichi Moriyama

Kenji Matsumoto

Kazunori Kawamura

Osamu Ishida

Hidetoshi Itou

Toshihiko Shinomura

Yuuzou Muraki

Katsuki Tsukamoto

The polymer film of the present invention has through holes extending from one principal surface of the polymer film to the other principal surface of the polymer film. The through holes are straight holes having a central axis extending straight, and have a shape in which the area of a cross-section perpendicular to the direction of the central axis increases from the one principal surface of the polymer film toward the other principal surface. This polymer film has passages in its thickness direction, has an unconventional structure, and can be used in various applications, such as in a waterproof sound-permeable membrane, in a waterproof gas-permeable membrane, and in a suction sheet. The ratio a/b of the opening diameter a of the through holes at the one principal surface to the opening diameter b of the through holes at the other principal surface is 80% or is less than 80%.

Polymer film, waterproof sound-permeable membrane, waterproof sound-permeable member, electronic device, electronic device case, waterproof sound transmission structure, waterproof gas-permeable membrane, waterproof gas-permeable member, waterproof ventilation structure, suction sheet, method for holding workpiece by suction on suction unit, method for producing ceramic capacitor, optical film, optical member, and composition

Provides is a waterproof sound-permeable membrane () adapted to permit passage of sound and prevent entry of water. The waterproof sound-permeable membrane () includes a sound-permeation region () having a polytetrafluoroethylene (PTFE) membrane (). The polytetrafluoroethylene membrane () has an average pore diameter of 0.02 &#x3bc;m or more and 0.1 &#x3bc;m or less as measured according to ASTM F316-86 and has a porosity of 5% or more and 25% or less. The waterproof sound-permeable membrane () is suitable for application to an electronic device containing an acoustic device.

Waterproof sound-permeable membrane and electronic device

Provided is a sliding member having excellent adhesion and slidability suitable for use as a transfer pad in an image forming apparatus. A sliding member () includes a porous body () that is a sintered body of ultrahigh molecular weight polyethylene (UHMWPE) particles and having a surface of the porous body () as a sliding surface (). The sliding surface () has a particle occupation ratio of 50% or less, and a surface roughness Ra of 2.0 &#x3bc;m or less. The sliding member () can be obtained by heating the porous body obtained by cutting the sintered body of UHMWPE particles to make the sliding surface () smoother than before the heating.

Sliding member and method of producing the same

A suction sheet () to be attached onto a suction surface () of a suction apparatus () that holds an object by vacuum suction is provided with a substrate () and a porous body (). The substrate () has one surface () and the other surface (), and the one surface () is brought into contact with the suction surface (). Further, a plurality of through holes () are provided in the substrate (). The porous body () has a thickness of 1.4 mm or less, and is adhered onto the other surface () of the substrate () so as to cover the through holes ().

Suction sheet

An object is to provide an electrolyte membrane that maintains excellent cell characteristics for a long time under high temperature and low water retention, as this is the most important point in fuel cells. A process for producing a polymer electrolyte membrane for fuel cells is provided, which process comprises in sequence: forming graft molecular chains by graft-polymerization of a vinyl silane coupling agent on a polymer film substrate that has phenyl groups capable of holding sulfonic acid groups; introducing sulfonic acid groups into phenyl groups contained in the graft molecular chains; and hydrolyzing and condensing alkoxy groups contained in the graft molecular chains so that a silane crosslinked structure is introduced between the graft molecular chains. A polymer electrolyte membrane produced by the process is also provided.

Silane crosslinked structure-introduced fuel-cell polymer electrolyte membrane and fuel-cell electrode assembly having the same

Polymer ion-exchange membranes having outstanding electrical conductivity, water retention and oxidation resistance are produced by the steps of uniformly mixing an organic high-molecular weight resin with functional inorganics having the abilities to promote graft polymerization of polymerizable monomers, adsorb water and conduct protons, irradiating the resulting functional inorganics/polymer membrane to initiate graft polymerization or graft copolymerization of polymerizable monomers having functional groups, and then introducing sulfonic acid groups into the graft chains.

Process or producing hybrid ion-exchange membranes comprising functional inorganics and graft polymer and electrolyte membranes for use in fuel cells comprising the hybrid ion-exchange membranes

The present invention relates to an electrolyte membrane including a graft polymer having a sulfonic acid group as a proton conductive group, in which, when the electrolyte membrane is divided into four equal parts in a thickness direction thereof, a content of the sulfonic acid group in each of outer regions is larger than a content of the sulfonic acid group in each of inner regions; in which A, A, Band Bsatisfy the following formula: 1.5&#x2266;(AA)/(BB)&#x2266;8, in which Aand Aeach represent a maximum value of a distribution amount of the sulfonic acid group in each of the two outer regions, and Band Beach represent an average value of a maximum value and a minimum value of a distribution amount of the sulfonic acid group in each of the two inner regions; and in which the electrolyte membrane has an ion-exchange capacity of 0.5 to 2 meq/g.

Electrolyte membrane

A crosslinked nano-inorganic particle/polymer electrolyte membrane composed of a polymer film substrate, graft molecular chains bound to the backbone skeleton of the polymer film substrate and comprising a vinyl monomer graft-polymerized, sulfonic groups bound to the graft molecular chains, and an inorganic material as nano-scale particles uniformly dispersed within a crosslinked structure ascribed to the backbone skeleton of the polymer film substrate and the graft molecular chains, wherein the backbone skeleton of the polymer film substrate, the graft molecular chains, and the nano-inorganic particles mutually construct a crosslinked structure.

Crosslinked nano-inorganic particle/polymer electrolyte membrane for membrane electrode assembly

By performing photograft polymerization of functional monomers such that grafted chains will be introduced from the surface of a polymer base film into its interior without deteriorating its inherent characteristics and also by creating a multiplex crosslinked structure between the grafted chains and the base film under such conditions as to cause preferential radiation-induced crosslinking reaction, there is produced a polymer electrolyte membrane having high enough oxidation resistance and proton conductivity to be suitable for use in fuel cells.

Process for producing polymer electrolyte membranes for fuel cells, polymer electrolyte membranes for fuel cells produced by the process, and fuel cell membrane-electrode assemblies using the membranes

A method for producing a polymer electrolyte membrane for electrolyte fuel cells includes: irradiating gamma rays onto a polymer substrate to obtain a crosslinked polytetrafluoroetylene substrate, grafting a styrenic monomer and bis(vinylphenyl)ethane as monomers to the crosslinked polymer substrate, and introducing sulfonic acid groups into graft side chains formed by grafting. Fluoro polymer substrates such as polytetrafluoroethylene and ethylene tetrafluoroethylene copolymer may be used.

Methods for producing a polymer electrolyte membrane having improved oxidation resistance

The objective of the invention is to solve the problems of conventional polymer electrolyte membranes, including small ion-exchange capacity and low oxidation and methanol resistance. A polymer film substrate is irradiated with &#x3b3;-rays, electron beams or other radiations to perform multi-graft polymerization with functional monomers and then the polymer film substrate containing the grafted molecular chains or the graft molecular chains into which sulfonic acid groups have been introduced is crosslinked by irradiation to produce a polymer electrolyte membrane that has outstanding oxidation resistance, dimensional stability, electrical conductivity and methanol resistance and which can be controlled in ion-exchange capacity over a wide range.

Highly durable polymer electrolytic membrane for a fuel cell having a cross-linked structure

Process for producing hybrid ion-exchange membranes comprising functional inorganics and graft polymer and electrolyte membranes for use in fuel cells comprising the hybrid ion-exchange membranes

A polymer electrolyte membrane for a polymer electrolyte fuel cell, that overcomes disadvantages of the conventional polymer ion-exchange membranes including fluorine-based polymer electrolyte membranes and can maintain cell characteristics even in use over a long period of time (e.g., several thousand hours). The polymer electrolyte membrane comprises a fluorine polymer substrate having grafted thereon monomers having sulfone groups as a cation-exchange group, wherein a main chain of the graft chain comprises a hydrocarbon or a partially fluorinated hydrocarbon, and sulfone groups or substituents having sulfone groups are bonded as a side chain, and wherein in element compositional ratio by ESCA, at least one surface of the polymer electrolyte membrane has O/S value of 5.0 or higher, and a surface element proportion of S is 0.4-5.0%.

Polymer electrolyte membrane having excellent durability

In a method of resin-encapsulating a semiconductor chip using a polytetrafluoroethylene film as the mold-releasing film, a polytetrafluoroethylene film F wherein the thermal shrinkage percentages thereof in both the longitudinal direction and the width direction are 5% or lower, the difference of the thermal shrinkage percentages is within 3%, and the ratio of the elastic modulus of the longitudinal direction to the elastic modulus of the width direction is from 0.5 to 2.0 during resin encapsulating is used. By using the mold-releasing film, resin encapsulating can be carried out with an excellent yield while preventing the occurrence of resin covering of the terminals or the top surfaces of the post electrodes.

Method of resin-encapsulating semiconductor chip and mold-releasing film used for the method

The release member has a thermoplastic layer sandwiched between stripping films such that it flows toward the hole upon melting when it is heated under pressure and the stripping film in contact with the laminate has a breaking elongation of not less than 600% and a 100% elongation load of not more than 350 gf per unit width of 1 cm at the temperature to which the laminate is heated.

Growing community of inventors

Ibaraki, Japan

Toshimitsu Tachibana