Showing papers on "Coating published in 1996"

Drug release stent coating process

Abstract: A method of coating implantable open lattice metallic stent prosthesis is disclosed which includes sequentially applying a plurality of relatively thin outer layers of a coating composition comprising a solvent mixture of uncured polymeric silicone material and crosslinker and finely divided biologically active species, possibly of controlled average particle size, to form a coating on each stent surface. The coatings are cured in situ and the coated, cured prostheses are sterilized in a step that includes preferred pretreatment with argon gas plasma and exposure to gamma radiation electron beam, ethylene oxide, steam.

Coated electrosurgical electrode

Abstract: A design and method of manufacture is disclosed for an electrosurgical electrode with a silicone coating The coating resists the buildup of eschar The silicone material is thick enough in the flat area of the blade to withstand the electrosurgical voltage without breakdown The electrosurgical current path is primarily through the blade edges and tip The flat of the blade remains insulated under most conditions The relatively thick coating also provides high tear strength and added durability The composition of the electrode coatings may include silicone elastomers in the form of adhesives, dispersions, or liquid rubbers The coating composition may also contain adhesion promoters, heat stabilizers, plasticizers, release enhancers, crosslinking agents, and colorants Several methods of manufacture are illustrated by way of examples

Oxygen diffusion barrier properties of transparent oxide coatings on polymeric substrates

Abstract: Gas diffusion properties of transparent thin film coatings have been under investigation by a number of workers for application in food and medical packaging. Work on the oxygen permeation properties of high barrier thin film coatings is reviewed, with emphasis on the coating thickness dependence of the oxygen permeation rate. Comparison of the coating thickness dependence of the oxygen permeation properties of evaporated, sputtered and plasma-deposited transparent oxide and organic coatings suggests that the reduction in permeation due to the coatings is limited by transport through coating defects (e.g. pinholes, grain boundaries or microcracks). The usefulness of such measurements as a probe of coating microstructure is assessed by reviewing structural and permeation investigations of metallized coatings on polymers.

Method of providing a substrate with a hydrophilic coating and substrates, particularly medical devices, provided with such coatings

Abstract: A substrate such as a catheter or a guide wire is provided with a lubricous, hydrophilic abrasion-resistant coating by: a) coating said substrate with a first aqueous coating composition comprising an aqueous dispersion or emulsion of a polymer having organic acid functional groups and a polyfunctional crosslinking agent having functional groups capable of reacting with organic acid groups, and drying the coating to obtain a substantially water-insoluble coating layer having excess polyfunctional including functional groups being reactive with organic acid groups remaining, and b) contacting the dried coating layer obtained in a) with a second aqueous coating composition comprising an aqueous solution or dispersion of a hydrophilic polymer having organic acid functional groups, and drying the combined coating, the hydrophilic polymer thereby becoming bonded to the polymer of the first coating composition through the excess crosslinking agent. The drying can be carried out at ambient (room) temperature.

A micro-abrasive wear test, with particular application to coated systems

Abstract: A test methodology is described which permits a rotating sphere test, also used to measure coating thickness, to be used as a small-scale abrasive wear test. The ability of the test to measure intrinsic wear resistance for thin coatings is demonstrated together with a new method of analysis which allows simultaneous evaluation of the wear resistance of both substrate and coating from their combined wear behaviour in a single test. The method has been applied to physically vapour deposited TiN, TiCN and TiAlN coatings on tool steel substrates, as well as to bulk samples of metals, ceramics and soda-lime glass.

Coating composition having anti-reflective and anti-fogging properties

Abstract: A coating composition which imparts anti-reflective and anti-fog properties to substrates coated therewith. The coating composition utilizes an inorganic metal oxide in combination with silane or a siloxane oligomer. The coating compositions are particularly useful in the manufacture of disposable surgical masks and face shields.

Electrosurgical clamping device with insulation limited bipolar electrode

Abstract: An electrosurgical hemostatic instrument is provided in which the coagulation status of tissue engaged by two elements delivering an electrosurgical energy to tissue may be observed, and in which damage from thermal spread may be minimized. A preferred embodiment of the invention provides a bipolar endoscopic clamping, coagulation and cutting device. In this device, the outer conductive surface of the tissue engaging elements is substantially covered by an insulative coating which confines current flow to the clamped tissue and limited regions around the tissue engaging elements. Coagulation may be observed by watching the region around the tissue engaging elements. Coagulation around the tissue engaging elements may be controlled by selectively coating the outside of the elements with insulation to control current flow from the surface of the engaging elements.

Protective coating for a stent with intermediate radiopaque coating

Abstract: The invention relates to coated stents and the method of making them. A stent that is substantially radiolucent is at least partially coated with a radiopaque layer that makes the stent visible under X-ray or fluoroscopy. A protective layer is coated on the stent and the radiopaque layer to protect both from scratches, flaking, and galvanic corrosion, and to improve both blood and bio-compatability.

Guidewire with variable flexibility due to polymeric coatings

Abstract: This invention is a guidewire for guiding a catheter and is used for accessing a targeted site within a lumen system in a body. The guidewire or guidewire section has a wire core, a distal tip region, a polymeric tie layer, and a lubricious coating. The tie layer is preferably constructed to provide for sections of varying flexibility along the length of the guidewire. Variations of the tie layer provide for axially spaced sections of varying flexibility, radially layers of varying flexibility of both. In a special variation, the tie layer is constructed with at least one section providing increased stiffness distally.

Multilayer coatings for improved performance

Abstract: Although single-layer coatings are finding a range of applications in many sectors of engineering, there are an increasing number of applications where the properties of a single material are not sufficient. One way to surmount this problem is to use a multilayer coating that combines the attractive properties of several materials, each chosen to solve a problem in the application. Simple examples of this include the use of interfacial bonding layers to promote adhesion, or thin inert coatings on top of wear-resistant layers to reduce the corrosion of cutting tools. There is, however, mounting evidence that the multilayer structure produced when many alternating layers of two materials are deposited can lead to improvements in performance over a mixed coating (by virtue of the introduction of new interfaces) even if the two materials do not have specific functional requirements in the intended application. In this paper results for multilayer coatings in the TiN system will be presented showing the advantages of compositionally and structurally modulated coatings over conventional single-layer titanium nitride coatings in tribological applications. The results will be discussed in light of the microstructure and properties of the coatings produced by the two different multilayer coating techniques.

Effect of roughness as determined by atomic force microscopy on the wetting properties of PTFE thin films

Abstract: The influence of film roughness on the wetting properties of vacuum-deposited polytetrafluorethylene (PTFE) thin films has been investigated using atomic force microscopy (AFM) and contact angle goniometry. Surface roughness has been characterized by atomic force microscopy in terms of RMS roughness (Rq) and fractal dimensions. A contact angle correlation with surface roughness, as determined by AFM, is evident from these results, which are discussed on the basis of wetting theory. The results also confirm that the high water contact angles (as high as 150°) recently observed at the surface of a new water repulsive coating material (mixture of PTFE and binder) are because of surface roughness. Such measurements clarify the effect of nanometer-size surface asperities on the wetting properties of hydrophobic coating.

Method for forming a dielectric tantalum nitride layer as an anti-reflective coating (ARC)

Abstract: The present invention provides an anti-reflective Ta3 N5 coating which can be used in a dual damascene structure and for I line or G line lithographies. In addition, the Ta3 N5 coating may also be used as an etch stop and a barrier layer. A dual damascene structure is formed by depositing a first dielectric layer (16). A dielectric tantalum nitride layer (18) is deposited on top of the first dielectric layer. A second dielectric layer (20) is deposited on the tantalum nitride layer. A dual damascene opening (34) is etched into the dielectric layers by patterning a first opening portion (26) and a second opening portion (32) using photolithography operations. Dielectric tantalum nitride layer (18) serves as an ARC layer during these operations to reduce the amount of reflectance from conductive region (14) to reduce distortion of the photoresist pattern. The use of a dielectric tantalum nitride layer as an ARC is particularly suitable for I line and G line lithography.

Biocompatible medical article and method

Abstract: A medical article having a metal or glass surface with the surface having an adherent coating of improved biocompatibility. The coating is made by first applying to the surface an silane compound having a pendant vinyl functionality such that the silane adheres to the surface and then, in a separate step, forming a graft polymer on the surface with applied vinylsilane such that the pendant vinyl functionality of the vinylsilane is incorporated into the graft polymer by covalent bonding with the polymer. Biomolecules may then be covalently attached to the base layer.

The interface crack problem for a nonhomogeneous coating bonded to a homogeneous substrate

Abstract: The debonding problem for a composite layer that consists of a homogeneous substrate and a non-homogeneous coating is considered. It is assumed that the problem is one of plane strain or generalized plane stress and the elastic medium contains a crack along the interface. It is further assumed that the thermomechanical properties of the medium are continuous functions of the thickness coordinate with discontinuous derivatives and the kink line of the property distributions corresponds to the “interface”. The mixed-mode crack problem is formulated for arbitrary crack surface tractions and sample results are given for uniform normal and shear tractions. The main variables in the problem are two dimensionless length parameters and a nonhmogeneity constant. Calculated results consist of primarily the stress intensity factors and the strain energy release rate and are partly intended to provide benchmark solutions for further numerical studies.

Titanium dioxide-based photocatalytic coating substrate, and titanium dioxide-based organic dispersions

Abstract: The invention relates to a substrate having on at least a portion of one of its faces a photocatalytic coating based on titanium dioxide at least partially crystallized and incorporated into the coating partially in the form of substantially crystallized in anatase form. The invention also relates to a method for preparing such substrates and to organic dispersions of titanium dioxide particles used in said process for preparing this substrate.

Medical apparatus with scratch-resistant coating and method making same

Abstract: A method for providing a medical apparatus with a protective surface coating is described. The method comprises applying to a medical apparatus a coating solution that contains a matrix polymer such as a urethane, and a reinforcing agent such as lamellar platelet and fiber additives, as micaceous pigments, flake pigments, tungsten powder and glass fiber, to increase the resistance of the medical apparatus to injury, such that the surface coating forms a protective, scratch- and puncture-resistant layer on the medical apparatus. The particles or fibers of the reinforcing agent may be oriented to provide the medical apparatus with additional resistance to injury. The coating is well suited to provide balloon catheters, particularly PET balloons, and the like with the toughness desirable for use in stent delivery and placement.

Proppants with fiber reinforced resin coatings

Abstract: Coated particles made of particulate substrates having a coating of resin and fibrous material are provided for use in subterranean formations. The coated substrate particles are proppants useful to prop open subterranean formation fractures. The coated substrate particles are also useful for sand control, that is, acting as a filter or screen to prevent backwards flow of sand, other proppants or subterranean formation particles. Methods of making the coated particles are also disclosed.

The oxidation and protection of gamma titanium aluminides

Abstract: The excellent density-specific properties of the gamma class of titanium aluminides make them attractive for intermediate-temperature (600–850 °C) aerospace applications. The oxidation and embrittlement resistance of these alloys is superior to that of the α2 and orthorhombic classes of titanium aluminides. However, since gamma alloys form an intermixed Al2O3TiO2 scale in air rather than the desired continuous Al2O3 scale, oxidation resistance is inadequate at the high end of this temperature range (i.e., greater than 750–800°C). For applications at such temperatures, an oxidation-resistant coating will be needed; however, a major drawback of the oxidation-resistant coatings currently available is severe degradation in fatigue life by the coating. A new class of oxidation-resistant coatings based in the Ti-Al-Cr system offers the potential for improved fatigue life.

Hardfacing with coated diamond particles

Abstract: Hardfacing to protect wear surfaces of drill bits and other downhole tools having coated diamond particles (44) dispersed within and bonded to a metallic matrix deposit (20). The coating (42) on the diamond particles (44) may be formed from materials and alloys such as particles of tungsten carbide, and tungsten carbide/cobalt and cermets such as metal carbides and metal nitrides. The coated diamond particles (40) are preferably sintered and have a generally spherical shape. The coated diamond particles (40) are pre-mixed with selected materials such that welding and cooling will form both a metallurgical bond and a mechanical bond within the solidified metallic matrix deposit (20). A welding rod (70) is prepared by placing a mixture of coated diamond particles (40), hard particles such as tungsten carbide/cobalt (30), and loose filler material (74) into a steel tube (72). A substrate (24) is hardfaced by progressively melting the welding rod into a selected surface of the substrate (24) and allowing the melted material to solidify, forming the desired hardfacing with coated diamond particles (40) dispersed therein on the substrate surface (22).

Pharmaceutical dosage form with multiple enteric polymer coatings for colonic delivery

Abstract: The present invention relates to a pharmaceutical composition in a unit dosage form for peroral administration in a human or lower animal, having a gastrointestinal tract comprising a small intestine and a colon with a lumen therethrough having an inlet to the colon from the small intestine, comprising: (a) a safe and effective amount of a therapeutically active agent incorporated into or coated on the surface of a dosage form selected from the group consisting of a spherical substrate, an elliptical substrate, a hard capsule, or a compressed tablet, with a maximum diameter of about 3 mm to about 10 mm; and (b) an enteric polymer coating material comprising at least one inner coating layer and one outer coating layer; wherein the dosage form has a smooth surface free from edges or sharp curves; the elliptical substrate and the hard capsule have a ratio of the long to short diameters of no greater than about 1.5; the therapeutically active agent is released at a point near the inlet to, or within the colon; each of the inner coating layer(s) is an enteric polymer that begins to dissolve in an aqueous media at a pH between about 5 to about 6.3; and the outer coating layer is an enteric polymer that begins to dissolve in an aqueous media at a pH between about 6.8 to about 7.2.