Medical devices

1. A method of manufacturing a device including a first layer, a second layer and a third layer, the method comprising:

selecting a material for the second layer, the material having a viscosity value at a shear rate of about 1 s −1 or less and at a selected temperature;

selecting a nanocomposite material for the first layer that has a viscosity within about 20% to about 125% of the viscosity value of the material for the second layer, wherein the nanocomposite material includes a polymer matrix having dispersed therein nanosized particles having a size of from 1 nm to 1000 nm;

selecting a material for the third layer, the third material being selected such that the viscosity of the second material is between about 5 percent and about 35 percent of a viscosity of the third material;

co-extruding the first, second and third layers.

2. The method of claim 1 , wherein the device comprises a medical device.

3. The method of claim 1 , wherein the device comprises a catheter.

4. The method of claim 1 , wherein the shear rate is below about 0.5 s −1 .

5. The method of claim 1 , wherein the shear rate is about 0.1 s −1 .

6. The method of claim 1 , wherein the selected temperature is about 60° C. to about 120° C. above a flow temperature of a highest flow temperature material co-extruded.

7. The method of claim 1 , wherein the device is a medical device, the method comprising:

forming a tubular member, the tubular member comprising the first layer, the second layer and the third layer co-extruded with the first layer, and one of the layers comprises a thickness that varies by less than about 20% from a mean value of thickness, the thickness being measured at four points per cross-sectional cut made at ten random, non-consecutive locations along a production length of the tubular member; and

incorporating a portion of the tubular member as a component of the medical device.

8. The method of claim 7 , wherein the medical device is a catheter.

9. The method of claim 7 , wherein the medical device is a balloon-catheter.

10. The method of claim 7 , wherein the thickness varies by less than 15% from the mean value of thickness.

11. The method of claim 7 , wherein the thickness varies by less than 10% from the mean value of thickness.

12. A high precision method of manufacturing a medical device having a three-layer elongate shaft, the method comprising the steps of:

providing a first material that will form an outer layer of the elongate shaft, the first material comprising a nanocomposite material having a first viscosity measured at a shear rate of 1 s −1 and a temperature of 220° C., wherein the nanocomposite material includes a polymer matrix having dispersed therein nanosized particles having a size of from 1 nm to 1000 nm;

providing a second material that will form a middle layer of the elongate shaft, the second material comprising a polyolefin having a second viscosity measured at a shear rate of 1 s −1 and a temperature of 220° C.;

providing a third material that will form an inner layer of the elongate shaft, the third material comprising a high density polyethylene having a third viscosity measured at a shear rate of 1 s −1 and a temperature of 220° C.; and

co-extruding the first material, the second material and the third material to form the three-layer elongate shaft;

wherein the first viscosity has a value that is between 25 percent and 125 percent of the second viscosity and the second viscosity is between 5 percent and 35 percent of the third viscosity.

13. The method of claim 12 , wherein providing a first material comprises providing a first material having a first viscosity, measured at a shear rate of 1 s −1 and a temperature of 220° C., of about 2,750 Pa·s.

14. The method of claim 12 , wherein providing a first material comprises providing a first material having a first viscosity, measured at a shear rate of 1 s −1 and a temperature of 220° C., of about 1,200 Pa·s.

15. The method of claim 12 , wherein providing a second material comprises providing a second material having a second viscosity, measured at a shear rate of 1 s −1 and a temperature of 220° C., of about 3,500 Pa·s.

16. The method of claim 12 , wherein providing a third material comprises providing a third material having a third viscosity, measured at a shear rate of 1 s −1 and a temperature of 220° C., of about 10,500 Pa·s.

17. The method of claim 12 , wherein providing a first material comprises providing a first material comprising nanosized particles dispersed within a polyamide.

18. The method of claim 12 , wherein providing a second material comprises providing a second material comprising a maleic anhydride polyolefin.