Extruded tubing and catheters having helical liquid crystal fibrils
First Claim
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1. In an extruded plastic catheter which defines a tubular catheter body, the improvement comprising, in combination:
- said catheter body being substantially defined by an extruded, tubular first layer, said first layer comprising, intermixed together, from 1 to 40 weight percent of a liquid crystal polymer and 60 to 99 weight percent of a different, softer structural plastic matrix which is not a liquid crystal polymer, said liquid crystal polymer defining a separate phase from said structural plastic matrix, said first layer exhibiting at least a degree of circumferential orientation to provide an increased amount of rotational stiffness to at least a section of said catheter body, said separate phase of the liquid crystal polymer defining generally helically extending fibrils dispersed throughout essentially the entire volume of said first layer, said fibrils being formed from liquid crystal polymer plastic droplets dispersed in said structural plastic matrix.
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Abstract
Extruded catheters and other flexible plastic tubing may be manufactured with improved rotational and/or longitudinal stiffness, compared with catheters made of more conventional plastics. A tubing of liquid crystal polymer plastic-containing material may be extruded through a tube extrusion die while rotating the inner and outer die walls to provide circumferential shear to the extruded tube. Thus the liquid crystal polymer is oriented in a helical manner to provide improved properties, including greater rotational stiffness.
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Citations
19 Claims
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1. In an extruded plastic catheter which defines a tubular catheter body, the improvement comprising, in combination:
said catheter body being substantially defined by an extruded, tubular first layer, said first layer comprising, intermixed together, from 1 to 40 weight percent of a liquid crystal polymer and 60 to 99 weight percent of a different, softer structural plastic matrix which is not a liquid crystal polymer, said liquid crystal polymer defining a separate phase from said structural plastic matrix, said first layer exhibiting at least a degree of circumferential orientation to provide an increased amount of rotational stiffness to at least a section of said catheter body, said separate phase of the liquid crystal polymer defining generally helically extending fibrils dispersed throughout essentially the entire volume of said first layer, said fibrils being formed from liquid crystal polymer plastic droplets dispersed in said structural plastic matrix. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
- 11. An extruded plastic tubing which defines a tubular body, said tubular body defining a tubular layer which comprises a mixture of a minor portion of a liquid crystal polymer and a major portion of a structural plastic matrix which is not a liquid crystal polymer, said liquid crystal polymer defining a separate phase from said structural plastic matrix with the structural plastic matrix and the liquid crystal polymer phases comprising a blended mixture which is dispersed together, said tubular layer exhibiting at least a degree of circumferential orientation to provide an increased amount of rotational stiffness to at least a section of said tube, the separate phase of said liquid crystal polymer defining generally helically extending fibrils dispersed throughout essentially the entire volume of said tubular layer.
Specification