Vascular prostheses composed of polytetrafluoroethylene and process for their production
AssigneeSumitomo Electric Industries, Ltd.
InventorKoichi Okita
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Abstract
A vascular prosthesis comprising a tubing of porous polytetrafluoroethylene, the polytetrafluoroethylene tubing having a fibrous structure of nodes and fibers connecting the nodes together and having a structure in which the fibrous structure at the inside surface of the tubing is finer than the fibrous structure at the outside surface of the tubing.
Claims19
A vascular prosthesis comprising a tubing of porous polytetrafluoroethylene, said polytetrafluoroethylene tubing having a fibrous structure of nodes and fibers connecting the nodes together and having a structure in which the fibrous structure at the inside surface of the tubing is finer than the fibrous structure at the outside surface of the tubing.
A process for producing a vascular prosthesis of a fibrous structure, which comprises extruding unsintered polytetrafluoroethylene containing a liquid lubricant into a tubing, stretching the tubing at least in the longitudinal direction of the tubing, fixing the tube to prevent shrinkage thereof during heating and then heating the stretched tubing so that the temperature of the outside surface of the tubing is at least 327.degree. C., and the temperature of the inside surface of the tubing is lower than that of the outside surface.
A process for producing a vascular prosthesis of a fibrous structure, which comprises extruding unsintered polytetrafluoroethylene containing a liquid lubricant into a tubing, stretching the tubing at least in the longitudinal direction of the tubing, fixing the tubing to prevent longitudinal shrinking during heating and then radially expanding the stretched tubing while heating the same tubing so that the temperature of the outside surface of the tubing is at least 327.degree. C., and the temperature of the inside surface of the tubing is lower than that of the outside surface.
Dependencies are inferred from the claim text.