Sumitomo Electric Industries, Limited

Agency of Industrial Science and Technology

Rikagaku Kenkyusho

Watanabe Pharmaceutical Industry Co., Ltd.

Koichi Okita

Shigeru Asako

Katsuya Yamada

Shinichi Toyooka

Shin-ichi Toyo-oka

Hiroshi Mano

Eiji Kamijo

Tohru Kashiwagi

Keishiro Tsuda

Takao Ogino

Tatsuya Nishimoto

Shuzo Nagai

Seiji Watabe

Shohei Isomura

Ryohei Nakane

Tsukasa Sakai

Kazuhiro Okabe

Makoto Kodama

Hiroshi Oinuma

Masaharu Komamiya

Sigeru Asako

A method for treating the surface of a thin porous film material of tetrafluoroethylene resin is disclosed, which comprises heating said surface to a temperature higher than the thermal decomposition point of said resin so as to decompose and remove part of said surface. The resulting thin porous film material of tetrafluoroethylene resin has an adhesive surface while retaining the desired pore size, hardness, and degree of penetration of adhesive.

Method for treating the surface of a thin porous film material of

Method for treating the surface of a thin porous film material

An antithrombogenic material is described, comprising an expanded polytetrafluoroethylene base having a collagen layer provided on the surface thereof, and further provided thereon a composite layer of collagen and a mucopolysaccharide, and said collagen is crosslinked with a crosslinking agent.

Antithrombogenic materials

A gas-selectively permeable membrane and a method of forming said membrane are described. This membrane is an asymmetrical pore diameter structure film made of a polyetherimide having the recurring unit represented by formula (A) or a mixture of said polyetherimide and at least one polymer having the recurring unit represented by formula (B), wherein the means pore diameter of a dense layer of the asymmetrical pore diameter structure film is 0.5 micron or less and the means thickness of the dense layer is 10 microns or less: ##STR1## wherein all the symbols are defined in the specification. This membrane is superior in heat resistance and is suitable for use in the isolation of argon from air, for the concentration of oxygen, for the concentration of hydrogen in twon gas, and so forth.

Gas-selectively permeable membrane and method of forming said membrane

A tubular prosthesis having a composite structure comprising (i) tubular polytetrafluoroethylene having a microfibrous structure comprising small nodes interconnected with fibrils and (ii) materials which can be absorbed by a living body wherein (a) said polytetrafluoroethylene has a greater average fibril length on the outer surface than on the inner surface, and the fibrous structure of said polytetrafluoroethylene varies continuously across the thickness of the tube wall wherein said inner surface has said fibrous structure being predominantly oriented along the axial direction and said outer surface has said fibrous structure being predominantly oriented along the concentric direction; and (b) said materials which can be absorbed by a living body are collagen, at least one of albumin and chitosan, and heparin, and are distributed in such a manner that collagen is present in the portion of the tube wall which is closest to the outer surface thereof while at least one of albumin and chitosan is present in the portion of the tube wall which is closest to the inner surface thereof, and heparin is present in the inner surface of the tube wall.

Tubular prosthesis having a composite structure

A liquid membrane is disclosed, which comprises a solvent, an active species capable of facilitated transport of a specific gas, and a support for maintaining a liquid body which has a mixture of said solvent and active species dissolved therein, said support being a porous polytetrafluoroethylene film one surface of which is hydrophobic and the other of which is hydrophilic.

Liquid membrane

A liquid membrane is disclosed, which comprises a solvent, an active species capable of performing facilitated transport of a specific gas, and a support for maintaining a liquid mixture of the solvent and the active species, wherein the active species has the structure represented by the following formula: ##STR1##

Apparatus for manufacturing a porous polytetrafluoroethylene material comprising extruding or rolling or a process consisting of the both an unsintered polytetrafluoroethylene mixture containing a liquid lubricant, and carrying out simultaneously next four steps of (a) evaporating a liquid lubricant, (b) stretching the molded articles in an unsintered condition, (c) sintering the same in a stretched condition, and (d) stretching the same in a sintered condition at an atmospheric temperature of more than 390.degree. C. to obtain mechanical strengths such as a Young's modulus of more than 10000 kg/cm.sup.2, and a matrix tensile strength of more than 1100 kg/cm.sup.2.

Apparatus for manufacturing porous polytetrafluoroethylene material

A gas-permselective composite membrane, and a process for producing the composite membrane are described. This composite membrane comprises a heat-resistant porous polymeric membrane and a thin layer of a tertiary carbon or tertiary organic silicon-containing compound provided on one side of the membrane, the layer being prepared by polymerizing the compound by means of plasma. The membrane has highly permselective as well as superior strength and heat resistance.

Gas-permselective composite membranes and process for the production

A process for producing a tube or rod of a polytetrafluoroethylene is described. The process comprises molding a polytetrafluoroethylene containing a liquid lubricant into a tube or rod by a paste process, removing the liquid lubricant, stretching the tube or rod in the lengthwise direction, and thereafter, by sintering the stretched tube or rod at a temperature of at least 327.degree. C. wherein the stretching of the tube or rod is carried out by the use of at least one pair of heating rolls which are each provided with a plurality of grooves. The process provided uniform stretching making it possible to produce a tube or rod with very small internal diameter.

Production of string-like polytetrafluoroethylene

A selectively gas-permeable composite membrane and a process for producing said composite membrane are described. The composite membrane comprises a polymeric material support and a thin membrane deposited on the support, said thin membrane being obtained by glow discharge plasma polymerization of an organosilane compound containing at least one double bond or triple bond. Alternatively, the composite membrane comprises a polymeric material support having an average pore diameter of at least 0.1 micron, a hardened or cross-linked polyorganosiloxane layer on the support, and a thin membrane on the polyorganosiloxane layer, said thin membrane being obtained by plasma polymerization due to glow discharge of an organosilane compound containing at least one double bond or triple bond.

Selectively gas-permeable composite membrane and process for production

Porous film materials composed of polytetrafluoroethylene having an asymmetric structure are produced by stretching the film using a pair of revolving rolls which are heated to a temperature lower than the melting point of the film. Stretching is produced by revolving the two rolls at different speeds which also tends to produce a compressive force in the thickness of the film. The rolls are heated to different temperatures to produce a temperature difference of preferably 50.degree. C. or more. The combination of the compressive force and the temperature gradient in the thickness of the film is believed to produce the asymmetric structure in the resulting porous film materials which are characterized by a fiber structure in the surface which is different from that in the back.

Production of asymmetric porous film materials

A catalyst for concentrating hydrogen isotopes for use in performing hydrogen isotopes exchange between gaseous hydrogen and liquid water, the catalyst comprising a support of porous polytetrafluoroethylene having a total specific surface area of 2 to 80 m.sup.2 /g as a result of mixing therewith 0.5 to 15% by weight of fluorocarbon or a porous styrene polymer or styrene/divinylbenzene copolymer having a specific surface area of at least 150 m.sup.2 /g, and deposited on the support particles of at least one element selected from Group VIII of the Periodic Table. A method for producing a support of porous polytetrafluoroethylene for such catalyst is also disclosed.

Catalyst for concentrating hydrogen isotopes and process for producing a

Polytetrafluoroethylene resin tubes having small pore size and high porosity are produced by a process which includes stretching the tubes by drawing using a metal die and a metal plug. By using the die and plug, the stress necessary for stretching is converted to a compressive force in the thickness direction of the tube. This compressive force is an essential factor in producing the microporous structure of the tubes. In addition, when stretching is performed by drawing, a ratio of thickness to inside diameter of the tube of 0.07 or less can be easily achieved.

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Osaka, Japan

Koichi Okita