156 results about "Expanded PTFE" patented technology

Vascular access systems for performing hemodialysis are disclosed. Some embodiments relate to vascular access grafts comprising an instant access or self-sealing material reinforced with expanded PTFE to resist stretching of the instant access material and thereby resist leakage associated with stretching or bending. The graft may comprise two end segments comprising ePTFE without the instant access material to allow easier anastomosis of the graft to veins and arteries. The graft may have a unibody design or have modular components that may be joined together to create a graft with customized length or other features. One or more sections of the graft may also be cut or trimmed to a custom length.

A solid polymer electrolyte membrane having a first surface and a second surface opposite the first surface, where the solid polymer electrolyte membrane has a failure force greater than about 115 grams and comprises a composite membrane consisting essentially of (a) at least one expanded PTFE membrane having a porous microstructure of polymeric fibrils, and (b) at least one ion exchange material impregnated throughout the porous microstructure of the expanded PTFE membrane so as to render an interior volume of the expanded PTFE membrane substantially occlusive; (c) at least one substantially occlusive, electronically insulating first composite layer interposed between the expanded PTFE membrane and the first surface, the first composite layer comprising a plurality of first carbon particles supporting a catalyst comprising platinum and an ion exchange material, wherein a plurality of the first carbon particles has a particle size less than about 75 nm, or less than about 50 nm, or less than about 25 nm.

A thin-wall PTFE (polytetrafluoroethylene) tube in the form of a tube of porous expanded PTFE film wherein the porous PTFE film has a microstructure containing a multiplicity of fibrils. The thin-wall tube is used in a non-porous embodiment as the balloon portion of a balloon catheter. The thin-wall tube is not elastomeric; however, because of the thinness, strength and flexibility of the tube, it may be inserted into a body conduit in a collapsed state and then deployed from a catheter and inflated up to the maximum diameter of the thin-wall tube. The porous PTFE film is provided with a continuous layer of adhesive to provide the non-porous tube; the adhesive is preferably a thermoplastic and more preferably a thermoplastic fluoropolymer such as fluorinated ethylene propylene.

A flat sheet membrane element for performing solid-liquid separation by immersion in a liquid to be treated which contains a suspended component includes sheet-shaped filtration membranes disposed opposite to each other with a space for a treated liquid flow path, a support portion for securing the space for the treated liquid flow path, and a peripheral sealing portion for sealing the peripheral edges of the filtration membranes arranged opposite to each other so as to form at least one treated liquid outlet, the filtration membranes including at least expanded PTFE (polytetrafluoroethylene) porous membranes.

The present invention is related to a low profile endolumenal prosthesis. The prosthesis comprises a radially expandable tubular wire support and an expanded PTFE membrane. The density, wall thickness and intranodal distance of the ePTFE are selected to inhibit the formation and nourishment of a viable neointima on the inner surface of the prosthesis, through the ePTFE membrane.

The present invention provides a vent assembly suitable for use with a respiratory mask of the type used in CPAP treatment. In one embodiment the vent is made of a thin air permeable membrane. Generally, the membrane is thinner than 0.5 mm. The membrane can be made of a hydrophobic material such as polytetrafluoroethylene (PTFE). The membrane can also be fabricated from expanded PTFE. The expanded PTFE membrane is mounted on a polypropylene scrim. The pores of the membrane have a reference pore size of 10 to 15 microns. In an alternative embodiment, the vent assembly includes a vent constructed from stainless steel. In another embodiment the membrane has a superficial cross-sectional area of approximately 500 mm². In another embodiment the vent assembly comprises a membrane attached to a vent frame, the vent assembly forming an insert which can be removeably attached to a mask fame.

This invention relates to a compound proton exchange film of a high temperature proton exchange film fuel battery, characterizing that said film is a multiplayer proton exchange film composite by multiplayer multi-hole polymer intensified compound proton exchange films. The multi-hole polymer is a buck Teflon micro-hole film, which makes up of the multi-hole polymer enhanced compound proton exchange film together with the inorganic nm particles and solid poly-electrolyte fillers. The preparation method of the exchange film is: a micro- pore film is pre-processed and fastened filled by inorganic nm particles and solid poly electrolytes to be rolled to single layer multi-hole polymer intensified proton exchange film to be laminated and hot-pressed to form a multiplayer proton exchange film.

A ballistic resistant article comprising high strength Kevlar fibers and expanded PTFE fibers, wherein the article is a fabric further comprising a V₅₀ of greater than about 1420 ft/s (433 m/s) at a fabric weight of about 0.75 lb/ft² (3.7 kg/sq m) and a bending moment at room temperature of less than about 0.0008 N-m. A ballistic resistant article comprising high strength Spectra fibers and expanded PTFE fibers, wherein the article is a fabric further comprising a V₅₀ of greater than about 735 ft/s (224 m/s) at a fabric weight of about 0.75 lb/ft² (3.7 kg/sq m) and a bending moment at room temperature of less than about 0.0007 N-m.

Provided is a porous multilayer filter which can trap ultrafme particles and in which permeability is high and treatment can be performed at a high flow rate. A porous multilayer filter is characterized by including a support layer 2 composed of a porous expanded PTFE sheet, and a filtration layer 3 composed of a porous expanded PTFE sheet which is different from that of the support layer 2, wherein at least a liquid-to-be-treated inflow surface of the filtration layer 3 is subjected to hydrophilization treatment, the filtration layer 3 and the support layer 2 are fusion-bonded to each other at a boundary therebetween to form a multilayer structure, pores of the support layer 2 three-dimensionally communicate with pores of the filtration layer 3, and pores surrounded by a fibril skeleton of the filtration layer 3 are smaller than pores of the support layer 2.

Taught herein is a venting media laminate having a microporous membrane layer, a fine fiber layer directly coupled to the microporous membrane layer, and a colorant disposed in the fine fiber layer. Also described is an acoustic venting assembly with a microporous membrane layer and a fine fiber layer having an average insertion loss no more than 100% more than the average insertion loss of the microporous membrane layer alone in the frequency range from 300 to 4000 Hz. Methods of manufacturing venting media is also described, where a colorant is added to the polymer solution which is spun to form a fine fiber layer. The fine fiber layer is laminated to an expanded PTFE membrane.

A low stress to seal, unitary gasket is provided that is particularly suited for applications requiring large gaskets. Gaskets of the present invention preferably comprise at least two windings of expanded PTFE tape wound at an increasing distance around a gasket inner periphery, wherein a substantially air impermeable layer is interposed between the tape windings. Preferably, the plane of the expansion of the ePTFE is substantially parallel to the flange surface, providing longitudinal and transverse strength. The substantially air impermeable layer prevents fluid from permeating through the gasket in the radial direction.

This invention discloses a process for shaping a novel composite proton exchange membrane. The process comprises: dissolving perfluorosulfonic acid in aqueous solution of low-boiling-point organic alcohol, adding high-boiling-point organic solvent and silica sol to obtain membrane-forming solution, dragging base membrane-expanded PTFE microporous membrane on the carry roller of a membrane-forming machine, soaking the base membrane in the low-concentration resin solution, drying at 40-100 deg.C, soaking in the high-concentration resin solution, drying at 40-100 deg.C, soaking and drying repeatedly until the thickness of the composite membrane reaches the predetermined value, and shaping the composite membrane in a drier at 120-200 deg.C. The process is simple, and suitable for mass production. The obtained composite proton exchange membrane has such advantages as high self-water-generating and water-retaining ability, high environmental adaptability, high strength and size stability, and long service life.

A method for manufacturing an expanded polytetrafluoroethylene (PTFE) plate comprises the following steps: sieving PTFE dispersion resins, adding a propellant and mixing the two materials, placing the mixed materials for 24h and then carrying out aging treatment, then carrying out pre-press shaping and extruding blanks, carrying out calendaring with two rollers, removing the propellant, carrying out composite shaping after biaxial tension and carrying out reshaping and trimming to finally manufacture the expanded PTFE plate. The expanded PTFE plate is a great breakthrough in the manufacturingprocess of molded plates and turning plates. The compression resilience, the tensile strength and the low stress relaxation rate of the expanded PTFE plate are obviously increased and the expanded PTFE plate obviously improves the performance defects of the fluoroplastics, thus meeting the demand of the use functions of the sealing elements and propelling the fluoroplastics to be one of the substitutes of the asbestos materials widely used at present in the sealing material field.

An intravascular device and method of constructing an intravascular device. The device has a proximal portion which is stiffer than a distal portion. The device of the present invention may also be advanced through small vessels without the aid of a guidewire although a guidewire may be used when necessary. The device may be manufactured in a number of different ways and a preferred method is to use an expanded PTFE liner at the distal portion and an etched PTFE liner along the proximal portion. The device also has a number of different jacket sections, preferably at least four, with increasing durometer towards the proximal end and a braided section with varying pic along the length.

The invention relates to full-frequency sound absorbing cotton which is provided with a double-layer structure or three-layer structure. The full-frequency sound absorbing cotton of the double-layer structure is composed of a melt-blow high polymer fiber layer and a varicosity polytetrafluoroethylene layer. The full-frequency sound absorbing cotton of the three-layer structure is composed of a melt-blow high polymer fiber layer with double faces compounded with the varicosity polytetrafluoroethylene layer or the varicosity polytetrafluoroethylene layer with double faces compounded with the melt-blow high polymer fiber layer. A high-performance composite micropore thin layer new material has better full-frequency sound absorbing capacity; is environment-friendly, non-toxic and free of peculiar smell, volatile gas, pollution or carcinogenic substances; and is free of stimulation caused by operating similar glass fiber on the skin, can be machined in punching mode, and does not generate dust or scraps and the like. The sound absorbing cotton made of the two materials of the melt-blow high polymer fiber layer and the varicosity polytetrafluoroethylene layer has good thermal resistance, and a sound absorbing effect cannot be affected by high-humidity climate and water.

A low stress to seal, unitary gasket tape is provided that is particularly suited for use in form-in-place gaskets. The gasket tape preferably comprises at least two joined porous expanded polytetrafluoroethylene (ePTFE) tapes aligned along tape side surfaces and a substantially air impermeable layer there between. The plane of expansion of the ePTFE is substantially parallel to the flange surface providing longitudinal and transverse strength. The substantially air impermeable layer prevents fluid from permeating through the gasket in the radial direction.

An electrical cable of the present invention comprises a plurality of spaced, parallel flat conductors. Each of the plurality of flat conductors was previously integral with each immediately adjacent flat conductor. A dielectric material is holds the conductors in the spaced, parallel relationship. The dielectric material can be a polymer film, a nonwoven, or other polymer materials such as PTFE, or expanded PTFE. The cable of the present invention is made by providing first and second webs of dielectric materials and a third sheet of conductive material. The first and second web materials are bonded to the third sheet of conductive material in a face-to-face layered relationship thereby forming a bonded laminate. The bonded laminate is then incrementally stretched to separate the sheet of conductive material in to spaced, parallel flat conductors.

The invention provides a preparation method of a sulfonated graphene modified perfluorosulfonate ion composite membrane. According to the ion composite membrane, an expanded PTFE microporous membrane serves as a base membrane. The method comprises the step that the base membrane is soaked in a sulfonated graphene perfluorosulfonate resin solution. Compared with the prior art, through doping of sulfonated graphene, self-discharge caused by permeation of vanadium ions is effectively prevented; meanwhile, the conductivity of the composite membrane is greatly improved compared with a Nafion membrane, and the improvement effect is more remarkable along with raise of temperature. Compared with a proton exchange membrane before sulfonated graphene modification, the maximum power of the composite membrane is increased by 80%.

The invention discloses a turbine type gas compressor front end dust remover and a filter element of the turbine type gas compressor front end dust remover. By means of the turbine type gas compressor front end dust remover and the filter element of the turbine type gas compressor front end dust remover, the phenomenon that a turbine type gas compressor is subjected to scaling after being used for a long time can be effectively improved. The front end dust remover comprises an outer shell, the filter element mounted in the outer shell, and a back-blowing dust cleaning device which acts on the filter element. The outer shell is connected with the filter element through a pore plate and forms a first space and a second space which are separated. Transmission of gas to be filtered happens in the first space, and the transmission of filtered gas happens in the second space. The filter element is provided with a filter material which is composed of a porous high-density polyethylene support body and an expanded polytetrafluoroethylene (PTFE) filter film, wherein the expanded PTFE filter film is closely attached to the surface of the porous high-density polyethylene support body. The removal rate of dust with a grain diameter of greater than or equal to 0.5 micrometer in the gas to be filtered by the expanded PTFE filter film is more than 99%. According to the turbine type gas compressor front end dust remover and the filter element of the turbine type gas compressor front end dust remover, the filter material can maintain stable and high filter precision for a long time, and therefore the phenomenon that the turbine type gas compressor is subjected to the scaling after being used for a long time can be effectively improved.

The present invention discloses discloses a composite PTFE membrane comprising an expanded PTFE membrane as substrate and a sintered porous PTFE membrane on top of it. The porous PTFE membrane on top has porous structure with interconnected channels formed with a sintering process that fuses the PTFE fine powders coated on the ePTFE membrane. Furthermore, the present invention discloses a method for forming the composite PTFE membrane.

The invention comprises several aspects which are each independently useful or which may be combined in a variety of combinations. One aspect of the invention is placing an atmospheric reference vent at or near the top of a rigid drip chamber for draining CSF from a patient. In the preferred embodiment, the vent is placed on the inside of the drip assembly, immediately next to the CSF. The vent, in another aspect of the invention, is made of a hydrophobic material. In the preferred embodiment, the hydrophilic material is expanded polytetraflouroethylene (e-PTFE). In yet another aspect of the invention, the vent is made of a porous material having a pore size that allows air to readily pass through while preventing CSF from passing through. A preferred embodiment of this aspect includes making the vent of expanded polytetraflouroethylene (e-PTFE) with a pore size ranging from about 0.22 μm to about 5.0 μm and more preferable a pore size of about 3 μm. With this pore size, the vent also preferably has a surface area ranging from about 0.5 cm² to about 5.0 cm².

The invention relates to a cable (10) having an elongate core (20) made of a first dielectric material and having a core outer surface (25); and a plurality of elongate conducting elements (30) arranged about the elongate core (20). The elongate conducting elements (30) have an inner conductor (40) surrounded by an insulating layer (50) which is made of a second dielectric material. The outer surface of the inner conductor (40) is divided into a first outer surface area (60) and a second outer surface are a (70) and the first outer surface area (60) is attached, for example by sintering, to the core outer surface (25). The first and second dielectric materials are preferably expanded PTFE. The cable (10) finds application in a streamer (100) for use in seismographic surveys of the ocean bottom sub surface.