METHODS OF MANUFACTURING NESTED BALLOONS UTILIZING PRESSURIZED CONSTRAINED ANNEALING
A nested balloon is provided where each balloon is formed from tubing that optimizes the inner wall stretch thus providing maximum balloon strength. The high pressure, nested balloon is provided with layers that allow for slipping, such that the balloon has a very high pressure rating and toughness, yet excellent folding characteristics. Methods for producing such nested balloons using existing balloon forming equipment are also provided. The nested balloons can have layers with low-friction surfaces. The nested balloons are preferably manufactured using a variety of methods, including pressurized constrained annealing.
1 . A method of manufacturing a nested balloon, comprising the steps of:
providing a first balloon layer;
providing a second balloon layer;
inserting the first balloon layer into the second balloon layer;
annealing the first balloon layer and the second balloon layer in a mold at a temperature of between about 200° F. and about 300° F. for a time period of between about 10 minutes and about 90 minutes; wherein annealing comprises pressurizing the nested balloon at a pressure of between about 2 atm and about 30 atm.
2 . The method of claim 1 , wherein the first balloon layer comprises nylon.
3 . The method of claim 1 , wherein the second balloon layer comprises nylon.
4 . The method of claim 1 , wherein the annealing temperature is between about 215° F. and about 255° F.
5 . The method of claim 1 , wherein the annealing temperature is about 235° F.
6 . The method of claim 1 , wherein the pressure is between about 10 atm and about 25 atm.
7 . The method of claim 1 , wherein the pressure is between about 15 atm and about 25 atm.
8 . The method of claim 1 , further comprising stretching the balloon with a stretch force of between about 1 pound and about 5 pounds.
9 . The method of claim 1 , wherein the time period is between about 15 minutes and about 45 minutes.
10 . The method of claim 1 , wherein the time period is between about 30 minutes.
11 . The method of claim 1 , further comprising the step of sterilizing the nested balloon after the annealing step at a temperature of between about 40° C. and about 60° C. for a time period of between about 1 hour and about 3 hours.
12 . The method of claim 1 , further comprising the step of blow-molding the first balloon layer and the second balloon layer prior to the annealing step, wherein the blow molding occurs no more than about 48 hours prior to the annealing step.
13 . The method of claim 1 , further comprising the step of blow-molding the first balloon layer and the second balloon layer prior to the annealing step, wherein the blow molding occurs no more than about 24 hours prior to the annealing step.
14 . The method of claim 1 , further comprising the step of welding the nested balloon to a catheter shaft to form a balloon catheter.
15 . The method of claim 1 , wherein the first balloon layer is a co-extruded balloon layer.
16 . The method of claim 1 , wherein the second balloon layer is a co-extruded balloon layer.
17 . The method of claim 1 , further comprising the step of inserting the second balloon layer into a third balloon layer.
18 . A nested balloon formed by the method of claim 1 .