Patent ID: 8313687
Filing Date: 2012-11-20
Classification: A61M,B29B,B29C,B29K,B29L

Abstract:
1. A method for making a balloon having differential wall thickness comprising the steps of: placing a raw tube having a lumen in an asymmetrical mold, said mold having an opening on each end through which the tube protrudes; holding said tube tightly on each end of said mold; preheating said mold and tube to a temperature between 50 and 120 ° C.; stretching said tube about 50 to 200 percent over a time period of between 5 and 60 seconds with pressure applied internally with air, nitrogen or another inert gas at about 0.5 bar, while the temperature is maintained; pressurizing said tube with pressure applied internally with air, nitrogen or another inert gas at a pressure between about 0.5 and 2 bar while allowing said tube to retract lengthwise by 10 to 50 percent over a time period of between 5 and 15 seconds, to form a balloon; heating the tube while still in the mold with its ends held tightly, to a temperature of 130-165 ° C. for a time of about 30-90 seconds and at a pressure to keep the balloon inflated; cooling said balloon at about 20-50 ° C.; collapsing said balloon so that it may be withdrawn without damage; removing said balloon from said mold; wherein the completed balloon has differential wall thicknesses, consisting of a continuous upper region having a thickness of from 15 to about 30 micrometers and consisting of a continuous lower region having a thickness of from about 5 to 15 micrometers.