Method for making liquid crystalline tube having a point

• US 5,151,231 A
• Filed: 09/26/1991
• Issued: 09/29/1992
• Est. Priority Date: 03/19/1990
• Status: Expired due to Term

• Current Assignee: Becton, Dickinson & Co
• Original Assignee: Becton, Dickinson & Co
• Inventors: Solomon, Donald D., Lambert, James M.
• Primary Examiner(s): Thurlow, Jeffery
• Application Number:
  US07/765,782
• Time in Patent Office: 369 Days
• Field of Search: 264/209.1, 264/209.3, 264/331.21, 264/108, 264/320, 264/328.12, 264/323, 264/162, 264/176.1, 264/296, 604/264, 425/144, 425/380, 128/772
• US Class Current: 264/108
• CPC Class Codes: A61L 29/04 Macromolecular materials
• CPC Class Codes: A61L 29/14 Materials characterised by their function or physical properties , e.g. lubricating compositions
• CPC Class Codes: A61M 25/0009 Making of catheters or other medical or surgical tubes
• CPC Class Codes: B29C 2045/0098 shearing of the moulding material, e.g. for obtaining molecular orientation or reducing the viscosity B29C45/0082 takes precedence
• CPC Class Codes: C08G 63/60 derived from the reaction of a mixture of hydroxy carboxylic acids, polycarboxylic acids and polyhydroxy compounds
• CPC Class Codes: C08G 63/605 the hydroxy and carboxylic groups being bound to aromatic rings

Abstract

A catheter assembly includes a tubing portion and a needle portion, at least one of which is a thermoplastic liquid crystalline polymer. The tubing and needle may be integral or unitary. The invention includes a method to make the assembly in which a melt of the liquid crystalline polymer is shear thinned by passing through an orifice such as an extrusion die to make tubing. The shear thinned melt may be directed into a mold having a point to make a liquid crystalline needle.

Claims

1. A method for preparing a liquid crystalline polymeric tubing having a point comprising:

a) heating a thermotropic liquid crystalline polymer to give a melt having a viscosity of 500 poise or less;

b) directing said melt into a tubing mold which includes a point whereby said melt completely fills said mold;

c) cooling said melt in said mold whereby said melt solidifies to a tubing having the shape of said mold; and

d) removing said tubing from said mold.

2. The method of claim 1 wherein said liquid crystalline polymer is selected from the group having structures I and II

3. The method of claim 1 wherein said melt is passed through an orifice under pressure prior to said directing step.

4. The method of claim 1 further comprising machining said point to further sharpen said point.

5. The method of claim 1 further comprising thermoforming said point in a heated tipping die to further sharpen said point.

6. A method for preparing a liquid crystalline polymeric tubing comprising:

a) heating a thermotropic liquid crystalline polyester to give a melt;

b) forcing said melt under pressure through an orifice whereby the viscosity of said melt decreases to about 500 poise or less;

c) directing said melt of reduced viscosity into a tubing mold which includes a point whereby said melt completely fills said mold;

d) cooling said melt in said mold whereby said melt solidifies to a tubing having the shape of said mold; and

e) removing said tubing from said mold.