Patent ID: 6287506
Filing Date: 2001-09-11
Classification: A61M,B29C,B29K,B29L,Y10S

Abstract:
A method of making dilatation balloons with reduced cone stiffness, comprising the steps of:(a) providing a mold having a cavity therein including a center section of a predetermined diameter defining a working length for a balloon to be formed therein and opposed end cone segments, each defined by an arcuate wall tangent to a wall defining the generally cylindrical center section and terminating in a cylindrical end segment corresponding to a desired shaft size for the balloon to be formed therein, the mold having opposed side edges spaced less than 0.25 inch from a point of intersection of the arcuate wall and the cylindrical end segment;(b) placing a tubular parison of a predetermined polymeric composition across the mold cavity, the tubular parison having opposed ends extending outwardly from the opposed side edges of the mold;(c) clamping the opposed ends of the tubular parison in longitudinally displaceable tensioning fixtures;(d) heating the mold to a temperature above the glass transition temperature of the polymeric composition of the parison;(e) longitudinally displacing the tensioning fixtures relative to the mold a first time to effect a first predetermined stretch ratio;(f) subsequently longitudinally displacing the tensioning fixture relative to the mold a second time to effect a second predetermined stretch ratio while simultaneously injecting a gas, under pressure, into the tubular parison to radially expand the parison against the walls defining the mold cavity and thereby form a balloon having a generally cylindrical center segment, a pair of opposed cone segments and a pair of opposed shaft segments;(g) further longitudinally displacing the tensioning fixture relative to the mold a third time to effect a third stretch ratio, the spacing of the opposed ends of the mold and the arcuate wall configuration of the mold end cone segments configured to effect selective thinning of the balloon cone and shaft segments;(h) heating the mold to the crystallizing temperature of the polymeric composition;(i) cooling the mold to a temperature below the glass transition temperature of the polymeric composition; and(j) removing the resulting balloon from the mold.