4281 results about "Tetrafluoroethylene" patented technology

A surgical implant is provided that includes first and second abutment surfaces between which are positioned a force imparting mechanism. A sheath is positioned between the first and second abutment surfaces, and surrounds the force imparting mechanism. The sheath is fabricated from a material that accommodates relative movement of the abutment members, while exhibiting substantially inert behavior relative to surrounding anatomical structures. The sheath is generally fabricated from expanded polytetrafluoroethylene, ultra-high molecular weight polyethylene, a copolymer of polycarbonate and a urethane, or a blend of a polycarbonate and a urethane. The force imparting member may include one or more springs, e.g., a pair of nested springs. The surgical implant may be a dynamic spine stabilizing member that is advantageously incorporated into a spine stabilization system to offer clinically efficacious results.

A process for the polymerization of a true tetrafluoroethylene (TFE) copolymer of the fine powder type is provided, wherein the copolymer contains polymerized comonomer units of at least one comonomer other than TFE in concentrations of at least or exceeding 1.0 weight percent, and which can exceed 5.0 weight percent, wherein the copolymer is expandable, that is, the copolymer may be expanded to produce strong, useful, expanded TFE copolymeric articles having a microstructure of nodes interconnected by fibrils.

A dispersion of non-melt-processible fluoropolymer particles having an SSG of less than about 2.225 in aqueous medium. The fluoropolymer particles comprise a core of high molecular weight polytetrafluoroethylene having an average melt creep viscosity greater than about 1.5×10¹⁰ Pa·s and a shell of lower molecular weight polytetrafluoroethylene or modified polytetrafluoroethylene. The shell has an average melt creep viscosity greater than about 9×10⁹ Pa·s and comprises about 5 to about 30% by weight of the particles. The fluoropolymer in the dispersion of the invention is fibrillating.

The present invention provides a tetrafluoroethylene polymer aqueous dispersion obtained by carrying out a TFE polymerization in an aqueous medium in the presence of a fluorovinyl group-containing emulsifier, wherein the TFE polymer aqueous dispersion contains a particle comprising a TFE polymer dispersed in the aqueous medium, the fluorovinyl group-containing emulsifier comprises a fluorovinyl group-containing compound, and the TFE polymer aqueous dispersion has a fluorine-containing surfactant content of not higher than 1000 ppm by mass.

The invention discloses a preparation method of polytetrafluoroethylene superfine fiber porous membrane. In the method, high concentration polytetrafluoroethylene aqueous emulsion is mixed with matrix polymer uniformly to prepare spinning solution. With the effect of high voltage electric field, polytetrafluoroethylene/matrix polymer composite superfine fiber porous membrane with the diameter of 100 nm to 2 [mu]m is obtained by electrostatic spinning, and then polytetrafluoroethylene superfine fiber porous membrane is formed at the conditions of sintering temperature being 330 to 500 DEG C and the sintering time lasting 30s to 5min so that the aperture diameter is 100 nm to 10 [mu]m and the porosity is 50% to 80%. The polytetrafluoroethylene superfine fiber porous membrane prepared by using the method has uniform aperture diameter and high porosity, and can be widely applied to filter material. Compared with the existing technology, the preparation method has the characteristics of simple processing technology, short process and low cost.

A catheter balloon formed of a polymeric material such as expanded polytetrafluoroethylene (ePTFE) bonded to a second layer formed of a low tensile set polymer and/or impregnated with a low tensile set polymer. In a presently preferred embodiment, the low tensile set polymer is a silicone-polyurethane copolymer elastomer or a diene polymer elastomer. The low tensile set polymer has high strength, low modulus, high elongation, and low tensile set. The diene or silicone-polyurethane has a low tensile set, which facilitates deflation of the balloon to a low profile deflated configuration. One aspect of the invention provides improved attachment of the diene to the ePTFE. In one embodiment, the second layer is formed of a diene mixed with a bonding promoter such as a vulcanizing agent which is covalently bonded to the diene.

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.

Water-repellant, self-cleaning coatings and methods of making and using thereof are described herein. In one embodiment, a hydrophobic or super hydrophobic coating is applied to the surface of a golf ball to make the golf-ball water-repellant and self-cleaning. Suitable coating materials include silicone compounds, silicone compounds, nanoparticles, silanes, fluorocarbon polymers, perfluoroalkyl ethyl methacrylate (PPFEMA) coated polycaprolactone, hydrocarbons, polymer mats made of polystyrene and poly[tetrafluoroethylene-co-(vinylidene fluoride)-co-propylene] (PTVFP); polyethylene glycol with glucose and sucrose in conjunction with a hydrophobic substance; combinations of nanoparticles with polyethylene or polypropylene; high density polyethylene, technical waxes; films of rough particles of metal oxides, polymer binder layers containing a plurality of porous protrusions, and combinations thereof. Suitable coating techniques include, but are not limited to, spraying, dipping, painting, brushing, or wiping (such as applying the coating from a towel or sponge). The coating material or the outer layer of the golf ball may be modified to create nano- or micro roughness or patterns on the surface of the golf ball, which can induce the lotus effect. This roughness or pattern can be created using a variety of techniques known in the art including, but not limited to, etching, top/down methodologies, bottom/up methodologies, or combinations thereof.

This invention concerns a method of manufacturing a highly conductive polytetrafluoroethylene sheet; a method of manufacturing a highly conductive unsintered polytetrafluoroethylene sheet: and a method of manufacturing a highly conductive sintered sheet. In the first method, a paste of polytetrafluoroethylene powder admixed with conductive substance and extrusion lubricant is extruded to preform an unsintered tube-like material, and at least one place on the circumference of this extruded material, the material is cut open longitudinally and the resulting sheet is calendered if necessary. The second method includes a sintering process for the sheet. This invention also concerns a highly conductive polytetrafluoroethylene sheet having a wide-width and long-length, which is obtained by the above-mentioned method. This sheet is not less than 170 mm in width and has variance of volume resistivity (conductivity) in the longitudinal direction, 10% or less, preferably 7% or less in the cross direction. This invention can provide a highly conductive wide-type PTFE sheet whose conductivity in the longitudinal direction is nearly uniform in the cross direction.

The invention relates to use of a tetrafluoroethylene/perfluoroolefin copolymer applied as a primer powder in conjunction with a powder overcoat of tetrafluoroethylene/perfluoro (vinyl alkyl ether) copolymer, also known as perfluoroalkoxy polymer (PFA), which when baked onto a substrate gives superior and more durable adhesion of the coating system to the substrate. The quality of the adhesion is measured by a boiling water peel test.

The invention relates to a surface hydrophilic modification method for a polytetrafluoroethylene bulked membrane, which is characterized by comprising the steps of: pretreating a polytetrafluoroethylene membrane by adopting low-pressure glow discharge plasma to make the surface of the polytetrafluoroethylene membrane generate active groups, and grafting acrylic acid to form a relatively stable hydrophilic layer. The method has the advantages that: the active groups are generated on the surface of the polytetrafluoroethylene membrane by low-pressure plasma treatment, and the relatively stable hydrophilic layer can be formed on the surface of the membrane by acrylic acid grafting treatment, so that the hydrophilicity of the polytetrafluoroethylene membrane is effectively improved, and the effect is lasting; and the polytetrafluoroethylene membrane is treated by the low-pressure plasma induction and acrylic acid grafting, so the treatment method is simple, high-efficiency, water and energy-saving, and suitable for industrialized production.

Modified polytetrafluoroethylene powder of a sinterable copolymer of tetrafluoroethylene containing about 0.5 to about 10 weight % of fluorinated vinyl ether, the copolymer having a melt creep viscosity of greater than about 1×10⁶ Pa·S. In preferred embodiments, the sinterable copolymer has a melt creep viscosity of greater than about 1×10⁷ Pa·S and fluorinated vinyl ether content of from about 1 to about 7 weight %. The polymer has a combination of a high level of fluorinated vinyl ether and a melt creep viscosity which is high enough to enable the fabrication of articles by sintering.

The invention discloses a preparation method of a talc filled PTFE (polytetrafluoroethylene) composite material. The method comprises the following steps in order: 1) conducting burdening with 50-99 wt% of PTFE, 1-50 wt% of talc powder, 0 wt%-10 wt% of filler I, and 0 wt%-20 wt% of filler II; 2) mixing the mixture obtained in step 1) uniformly, then carrying out cold pressing molding under a pressure of 25-40 MPa, and maintaining the pressure for 3-10 minutes; 3) putting the molded product obtained in step 2) into a high temperature sintering furnace, heating the product to a temperature of 360-380DEG C at a heating rate of 30-100DEG C/h, then preserving the heat for 0.5-2h; and 4) leaving the sintered product obtained in step 3) to natural cooling to room temperature, thus obtaining the talc filled PTFE composite material. The talc filled PTFE composite material prepared by the method of the invention has excellent performances and a wide application range.

An aqueous dispersion composition of about 30 to about 70 weight % non-melt-processible fluoropolymer particles having a standard specific gravity (SSG) of less than 2.225 and about 2 to about 11 weight % surfactant based on the weight of said fluoropolymer comprising a compound or mixture of compounds of the formula:

R(OCH₂CH₂)_nOH

wherein R is a branched alkyl, branched alkenyl, cycloalkyl, or cycloalkenyl hydrocarbon group having 8-18 carbon atoms and n is an average value of 5 to 18. The fluoropolymer particles of the dispersion comprise a core of high molecular weight polytetrafluoroethylene and a shell of lower molecular weight polytetrafluoroethylene or modified polytetrafluoroethylene. Preferably, the aqueous dispersion composition comprises about 45 to about 65 weight % non-melt-processible fluoropolymer particles.

The invention relates to a high temperature-resistant polytetrafluoroethylene tectorial filter material, belonging to the improvement on present polytetrafluoroethylene composite filter material, which comprises a glass fiber base cloth and a polytetrafluoroethylene surface film. It is characterized in that: first using after-treatment agent to process the dipping process on the glass fiber base cloth, then processing the high-temperature heat compression on the polytetrafluoroethylene surface film. The invention uses film forming emulsifier, fluorine silane coupling agent and fluoroplymer emulsion to form a film on the glass fiber base cloth, which can improve the effects of anti-soil, oil-proof and preservation, and it can have fusion combination with expanded micro-pore polytetrafluoroethylene film in the condition of high-temperature heat compression, to effectively solve the problem of hard fusion combination between inorganic material of glass fiber and organic inertia material of polytetrafluoroethylene to significantly improve the fastness between them.

Examples of the present invention include high electric energy density polymer film capacitors with high dielectric constant, low dielectric dissipation tangent, and low leakage current in a broad temperature range. More particularly, examples include a polymer film capacitor in which the dielectric layer comprise a copolymer of a first monomer (such as tetrafluoroethylene) and a second polar monomer. The second monomer component may be selected from vinylidene fluoride, trifluoroethylene or their mixtures, and optionally other monomers may be included to adjust the mechanical performance. The capacitors can be made by winding metallized films, plain films with metal foils, or hybrid construction where the films comprise the new compositions. The capacitors can be used in DC bus capacitors and energy storage capacitors in pulsed power systems.

Perfluoroelastomer compositions comprising perfluoroelastomers having copolymerized units of tetrafluoroethylene, a perfluoro(vinyl ether), and a nitrile-containing cure site monomer are cured with certain nitrogen-containing nucleophilic compounds. The nucleophilic compounds also act as dual curatives in perfluoroelastomer compositions which incorporate other curing agents.

Articles including expanded fluoropolymer membranes having serpentine fibrils are provided. The fluoropolymer membranes exhibit high elongation while substantially retaining the strength properties of the fluoropolymer membrane. The membrane may include a fluoropolymer and/or elastomer. Additionally, the article has an elongation in at least one direction of at least about 100% and a matrix tensile strength of at least about 50 MPa. The article may be formed by (1) expanding a dried, extruded fluoropolymer tape in at least one direction to produce an expanded fluoropolymer membrane and (2) retracting the expanded fluoropolymer membrane in at least one direction of expansion by applying heat or by adding a solvent. The application of a tensile force at least partially straightens the serpentine fibrils, thereby elongating the article. The expanded fluoropolymer membrane may include a microstructure of substantially only fibrils. The membranes may be imbibed with an elastomeric material to form a composite.

Articles comprising an expanded polytetrafluoroethylene membrane having serpentine fibrils and having a discontinuous coating of a fluoropolymer thereon are provided. The fluoropolymer may be located at least partially in the pores of the expanded fluoropolymer membrane. In exemplary embodiments, the fluoropolymer is fluorinated ethylene propylene. The application of a tensile force at least partially straightens the serpentine fibrils, thereby elongating the article. The expanded polytetrafluoroethylene membrane may include a microstructure of substantially only fibrils. The articles can be elongated to a predetermined point at which further elongation is inhibited by a dramatic increase in stiffness. In one embodiment, the articles are used to form a covered stent device that requires little force to distend in the radial direction to a first diameter but is highly resistant to further distension to a second diameter (stop point). A large increase in diameter can advantageously be achieved prior to reaching the stop point.

A vascular graft comprised of a tubular polytetrafluoroethylene (ePTFE) sheet is provided. The ePTFE sheet has a substantially uniform coating of bioresorbable gel material, for example gelatin, on a surface thereof. The coating minimises bleeding through suture holes in the ePTFE sheet and provides an increase in longitudinal extensibility.