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1. (WO2000001420) MEDICAL DEVICES MADE BY ROTATING MANDREL EXTRUSION
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What is claimed is:

1. A medical catheter having a shaft, defining a longitudinal axis which comprises:
a low-temperature thermoplastic polymer matrix having a melt temperature (Tm ); and

a plurality of low-temperature solid state liquid crystal polymer fibers embedded in said matrix, said liquid crystal polymer fibers having a melt temperature (Tf ) with Tf being less than approximately twenty degrees Centigrade above Tm (Tf < Tm + 20 °C), and said fibers being substantially arranged in a helical pattern around said longitudinal axis of said shaft and having an aspect ratio (A) greater than approximately fifty to one (A>50:1).

2. A shaft as recited in claim 1 wherein said low-temperature thermoplastic polymer matrix and said low- temperature liquid crystal polymer are incompatible, wherein said thermoplastic polymer matrix is a material selected from the group consisting of polyamides (nylon), polyurethanes, polyesters and polyolefms having processing temperatures below approximately two hundred and seventy degrees Centigrade (270 °C), and wherein said liquid crystal polymer has a processing temperature below approximately two hundred and seventy degrees Centigrade (270 °C ).

3. A shaft as recited in claim 1 wherein said thermoplastic polymer matrix and said solid state liquid crystal polymer fibers establish a ratio wherein said thermoplastic polymer matrix is in the range of approximately seventy percent to ninety nine percent by weight and, respectively, said liquid polymer fibers are in the range of approximately thirty percent to one percent by weight (70:18 - 99:1).

4. A shaft as recited in claim 1 wherein said shaft is a tube and said tube is formed with at least one longitudinally extending lumen.

5. A shaft as recited in claim 4 wherein said solid state liquid crystal polymer fibers are arranged in a helical pattern around the center longitudinal axis of said lumen.

6. A shaft as recited in claim 4 wherein said tube is a catheter.

7. A shaft as recited in claim 4 wherein said tube is a balloon in said medical device.

8. A method for manufacturing a medical device having a shaft for use which comprises the steps of:
blending a low-temperature thermoplastic polymer component having a melt temperature (Tm ) with a plurality of discrete low-temperature liquid crystal polymer particles having a melt temperature (Tf) to create a mix;
heating said mix to transition both said thermoplastic polymer component and said liquid crystal polymer particles to a substantially liquid phase to create a molten mix;
extruding said molten mix to form said shaft, said thermoplastic polymer component being formed as a matrix and said liquid crystal polymer particles being forced into a plurality of discrete elongated fibers, with each of said fibers being arranged in a helical pattern around the center longitudinal axis of said shaft and having an aspect ratio (A) greater than approximately fifty to one (A > 50:1); and
cooling said shaft.

9. A method as recited in claim 8 wherein said low-temperature thermoplastic polymer matrix and said low-temperature liquid crystal polymer fibers are incompatible, wherein said thermoplastic polymer matrix is a material selected from the group consisting of polyamides (nylon), polyurethanes, polyesters and polyolefms having processing temperatures below approximately two hundred and seventy degrees Centigrade (270 °C), and wherein said liquid crystal polymer fibers have a processing temperature below approximately two hundred and seventy degrees Centigrade (270 °C).

10. A method as recited in claim 8 wherein said blending step is accomplished to create a mix wherein said thermoplastic polymer matrix and said solid state liquid crystal polymer fibers establish a ratio wherein said thermoplastic polymer matrix is in the range of approximately seventy percent to ninety nine percent by weight and, respectively, said liquid crystal polymer fibers are in the range of approximately thirty percent to one percent by weight (70:18 - 99:1).

11. A method as recited in claim 8 further comprising the step of forming said shaft as a tube having at least one longitudinally extending lumen.

12. A method as recited in claim 8 wherein said solid state liquid crystal polymer fibers are substantially aligned in a helical arrangement around the center longitudinal axis of said lumen.

13. A method as recited in claim 12 further comprising the step of forming said tube with an integral balloon in fluid communication with said lumen.

14. A method as recited in claim 12 further comprising the step of controlling the speed of extrusion of said lumen, to obtain a desired helical pitch in said helical arrangement.

15. A method as recited in claim 8 wherein Tf is less than approximately twenty degrees Centigrade above Tm, (Tf < Tm + 20 °C).

16. A method as recited in claim 15 wherein T is within approximately twenty degrees Centigrade of T.