Abstract:
Bioresorbable polymeric tubes suitable for use in a stent have been produced by a using a die drawing technique, comprising: —deforming an orientable, thermoplastic polymer tubing (4) in the solid phase by drawing it over a mandrel (1) and/or through a die (3), where the mandrel (1) has a lead end and an exit end and the die (3) has an entry side and an exit side, wherein a drawing mechanism applies a drawing tension to the tubing (4) from the exit end of the mandrel (1) and/or the exit side of the die (3), said tension being insufficient to cause tensile failure of the tubing but sufficient to deform the tubing, thereby drawing the tubing over the mandrel (1) and/or through the die (3) in the solid phase to induce uniaxial or biaxial orientation of the polymer; and —collecting the deformed tubing from the exit end of the mandrel (1) and/or the exit side of the die (3).
Abstract:
Method for shaping expanded polytetrafluoroethylene tubes into a shaped three-dimensional article, comprising the steps of extruding an admixture of polytetrafluoroethylene resin and lubricant into a tubular extrudate, drying the tubular extrudate of at least a major fraction of lubricant, longitudinally expanding the tubular extrudate to impart a polytetrafluoroethylene microstructure having a plurality of nodes interconnected by fibrils, at least partially sintering the longitudinally expanded tubular extrudate to impart a dimensional stability in the tubular extrudate greater than the unsintered tubular extrudate, radially expanding the at least partially sintered tubular extrudate to a diameter greater than that of the tubular extrudate by introducing the tubular extrudate into a constraining chamber having an inner surface and an inner diameter 200 to 400 % greater that the outer diameter of the tubular extrudate and by applying a radially directed force against the lumenal surface of the tubular extrudate, so that the outer surface of the tubular extrudate is radially expanded into intimate contact with the inner surface of the constraining chamber, engaging the radially expanded at least partially sintered tubular extrudate circumferentially about a shaping mandrel, the shaping mandrel having a three-dimensional conformation and heating the shaping mandrel and the at least partially sintered tubular extrudate, thereby shrinking the partially sintered tubular extrudate into intimate contact with the shaping mandrel thereby shaping the partially sintered tubular extrudate about the shaping mandrel.
Abstract:
In a balloon tube (10) which is processed after it is mounted on a mold, a bag part (14) has a plurality of parts having a different drawability in a radial direction centered around an axial direction X, disposed along the axial direction X. The highest drawability part (11), which has the highest drawability, is disposed to separate from both ends of the bag part (14) in the axial direction X thereof. The balloon tube (10) is preferable to stably fabricate a balloon having a uniform film thickness.
Abstract:
Methods for making scaffolds for delivery via a balloon catheter are described. The scaffold, after being deployed by the balloon, provides a crush recovery of about 90% after the diameter of the scaffold has been pinched or crushed by 50%. The scaffold structure has patterns that include an asymmetric or symmetric closed cell, and links connecting such closed cells.
Abstract:
A method for making a vascular graft includes providing a PTFE green tube extrudate (12) which is un-sintered, and then initially expanding the un-sintered extrudate (17) to produce an initial node and fibril micro-structure therein. This is followed by heating the extrudate to raise the temperature thereof for a time period of sufficient duration such that the extrudate is partially sintered. The partially sintered extrudate is subsequently expanded (25) to make the vascular graft. The subsequent expansion produces a subsequent node and fibril microstructure in the vascular graft. An alternative method for making a vascular graft includes providing a PTFE green tube extrudate which is un-sintered, longitudinally expanding the unsintered extrudate to form an ePTFE tube structure, and radially expanding the un-sintered ePTFE tube structure. ePTFE made according to the method is fabricated into various structures, such as tube structures, filament structures, and sheet structures.
Abstract:
Method for shaping a material with a reticular structure, plant for performing same and reticular material resulting from the method. This method is applicable for handling a reticular tubular structure, in particular one of those obtained by extruding a synthetic plastics material, wherein its filaments, which form the sides of the net mesh, have a greater thickness at the crossover points than the actual thickness of the filaments. This method consists in the synthetic plastics material with a reticular tubular structure being subjected, while hot and with its tubular flattened shape, to two-dimensional molecular orientation operations, through drawing, followed by an operation to equal the thicknesses of the reticular tubular reticular structure by laminating it in a calendering machine.
Abstract:
Method for shaping a material with a reticular structure, plant for performing same and reticular material resulting from the method. This method is applicable for handling a reticular tubular structure, in particular one of those obtained by extruding a synthetic plastics material, wherein its filaments, which form the sides of the net mesh, have a greater thickness at the crossover points than the actual thickness of the filaments. This method consists in the synthetic plastics material with a reticular tubular structure being subjected, while hot and with its tubular flattened shape, to two-dimensional molecular orientation operations, through drawing, followed by an operation to equal the thicknesses of the reticular tubular reticular structure by laminating it in a calendering machine.
Abstract:
A method of shaping three-dimensional products by manipulating an expanded polytetrafluoroethylene tubular body into a desired three-dimensional conformation. The present invention entails radially expanding a longitudinally expanded polytetrafluoroethylene (ePTFE) tube (48) to form a radially expanded ePTFE (rePTFE) tube, engaging the rePTFE tube circumferentially about a shaping mandrel (50, 70, 140), heating the assembly to a temperature below the crystalline melt point temperature, or sintering temperature, of polytetrafluoroethylene to radially shrink the diameter of the rePTFE tube into intimate contact with the shaping mandrel, and heating the assembly to a temperature above the crystalline melt point temperature of polytetrafluoroethylene to amorphously lock the microstructure of the shaped polytetrafluoroethylene body.