High strength balloon
A balloon catheter includes a balloon which is both of high strength and radiopaque. The balloon includes an outer strengthened layer which includes a strengthening element at least partially embedded within the layer. Concentrically within the strengthened layer there is a radiopaque layer which includes a high concentration of radiopaque material distributed in the radiopaque layer. The strengthened layer acts as a support to the radiopaque layer which is otherwise be unable to withstand the pressure to which the balloon is normally inflated for deployment and in the course of a medical procedure. The structure provides a high strength radiopaque balloon with a relatively thin balloon wall optimizing balloon flexibility and wrappability. There is also disclosed a method of making a balloon which uses an internal support layer in a raw tubing which is then removed following formation of a balloon.
1. A method of manufacturing a balloon for a balloon catheter, the balloon including a plurality of layers superimposed on one another and having inner and outer balloon surfaces, a first of said layers being a strengthening layer and a second of said layers being a substantially radiopaque layer, the radiopaque layer being positioned inside the strengthening layer; the method including the steps of:
providing a raw tubing including at least one layer of a polymer material,
providing a radiopaque layer inside the layer of raw tubing, the radiopaque layer being the innermost layer of the raw tubing,
providing an expandable support concentrically inside the radiopaque layer,
inflating the raw tubing, radiopaque layer and expandable support in a mold so as to form said balloon, the balloon being formed on an interior surface of the mold, and
removing the expandable support from the produced balloon.
2. A method according to claim 1 , wherein the radiopaque layer and the strengthening layer are formed together as a unitary layer.
3. A method according to claim 1 , wherein the radiopaque layer is formed integrally with the raw tubing as a multi-layered tubing wherein the radiopaque layer and the raw tubing are in contact with each other.
4. A method according to claim 1 , wherein the radiopaque layer is coextruded with the layer of polymer material.
5. A method according to claim 1 , including the step of providing a strengthening element to said layer of polymer material, said strengthening element being provided in the mold and being attached, bonded to or embedded in the polymer layer on inflation of the raw tubing.
6. A method according to claim 5 , including the step of softening or melting the polymer layer so as to cause the polymer layer to flow around the strengthening element so as to embed at least partially the strengthening element therewithin.