Medical balloon with incorporated fibers
A balloon catheter assembly comprises a balloon having attached to or in its wall one or more filar elements, extending from one end of the balloon to the other. The filar elements are made of a material which is at least as flexible as the material forming the walls of the balloon. In the event of circular burst of the balloon, the filar element(s) prevent disconnection of the material of the balloon into two or more separate pieces. The filar element(s) become attached to or in the material of the balloon wall when the raw material is inflated to the shape of a mold. The filar elements may comprise a natural fiber, a synthetic fiber or a metal wire.
1. A method of forming a balloon for a balloon catheter, including the steps of:
providing a mold having an inner surface;
inserting a balloon material in the mold, the balloon material having only two layers, an outer layer of a first material and an inner layer of a second material, wherein a softening or melting temperature of the first material is lower than a softening or melting temperature of the second material;
providing one or more filar elements through the mold outside of the outer layer and there are no filar elements which extend circumferentially around the balloon;
heating the balloon material in the mold including softening the outer layer to at least a softening temperature; and
inflating the balloon material to the shape of the mold to form the balloon, wherein the inflating includes pushing the one or more filar elements towards the inner surface of the mold to at least partially embed the one or more filar elements in the outer layer but not the inner layer.
2. A method according to claim 1 , wherein the one or more filar elements are at least as flexible as the balloon wall.
3. A method according to claim 1 , wherein the one or more filar elements provide no material scoring or abrading function.
4. A method according to claim 1 , wherein the filar elements are at least as flexible as the balloon wall at least in a longitudinal direction of the balloon.
5. A method according to claim 1 , wherein the one or more filar elements or elements are compressible.
6. A method according to claim 1 , wherein the one or more filar elements have a diameter of between around 0.01 millimeters and 0.05 millimeters.
7. A method according to claim 1 , wherein the one or more filar elements have a linear density (dtex) of between 10 and 60.
8. A method according to claim 1 , wherein the one or more filar elements are multi-filamentary, each having from around 5 to 50 strands per element.
9. A method according to claim 8 , wherein the one or more filar elements are around 25 strands.
10. A method according to claim 8 , wherein each strand has a density of around 0.5 to 2 denier.
11. A method according to claim 1 , wherein the one or more filar elements have a tensile strength of between around 4 N to around 20N.
12. A method according to claim 1 , wherein the one or more filar elements exhibit an elongation at break of no more than around 5%.
13. A method according to claim 1 , wherein the one or more filar elements are at least one of: completely embedded in the balloon wall and partially embedded in the balloon wall.
14. A method according to claim 1 , wherein the balloon material is formed by co-extruding raw material to form a balloon wall comprising an outer layer of the first material and an inner layer of the second material.
15. A method according to claim 1 , wherein each of the one or more filar elements is completely embedded in the balloon wall.