Method of constructing a catheter

• US 3,879,516 A
• Filed: 12/07/1972
• Issued: 04/22/1975
• Est. Priority Date: 12/07/1972
• Status: Expired due to Term

• Current Assignee: Sidney Wolvek
• Original Assignee: Sidney Wolvek
• Inventors: Wolvek, Sidney
• Primary Examiner(s): Kucia, Richard R.
• Application Number:
  US05/313,124
• Time in Patent Office: 866 Days
• Field of Search: 264/255,264,135,88,305
• US Class Current: 264/135
• CPC Class Codes: A61M 25/0012 with embedded structures, e.g. coils, braids, meshes, strands or radiopaque coils
• CPC Class Codes: A61M 25/005 with embedded materials for reinforcement, e.g. wires, coils, braids

Abstract

A catheter which is relatively rigid in compression and torsion while flexible in bending includes a unitary tubular member including inner and outer layers of a soluble polymer composition, such as polyurethane, whose adjoining surfaces are chemically bonded during manufacture. A filament core, preferably in the form of a coil of the same polymer is embedded within and chemically bonded to the tubular member to form a catheter whose molecules are aligned both longitudinally and along the direction of the coil. Methods of manufacture of the catheter include forming the polymer composition layers within a rigid tube and, alternatively, forming the layers over a rigid supporting rod.

Claims

1. A method of constructing a catheter comprising the steps of forming an outer catheter layer by dissolving a flexible plastic material in a solvent;

drawing a film of said dissolved flexible plastic material onto the interior surface of an elongate rigid tube, said rigid tube being formed of a material which does not react chemically with said flexible plastic material and said solvent, causing the dissolved plastic material to gel by exposing it to the ambient atmosphere for a predetermined amount of time;

baking said material for a specified time at a specified elevated temperature to expel residual solvent contained therein;

repeating the drawing, gelling and baking steps, each succeeding film liquifying and bonding to the surfaces of the previously drawn film with which it contacts, until a layer of material having a predetermined thickness is built up on the interior of the rigid tube;

extruding a thin filament of said flexible plastic material;

forming said filament into a helical coil and heat setting said coil;

inserting said coil within the built up outer layer;

forming an inner catheter layer by drawing a film of said dissolved flexible plastic material onto the interior surface of said built up outer catheter layer and around said coil, said film causing the surfaces of the previously drawn films and helical coil with which it contacts to liquify so that the film bonds to said previously drawn films and coil, causing the dissolved material to gel by exposing it to the ambient atmosphere for a predetermined amount of time;

baking said material for a specified time at a specified elevated temperature to expel residual solvents;

repeatIng the drawing, gelling and baking steps each succeeding film liquifying and bonding to the surfaces of the previously drawn film and helical coil with which it contacts until a layer of material having a predetermined thickness is built up on the interior of the outer layer embedding said coil;

subjecting said outer layer, inner layer and embedded coil to a final bakeout at an elevated temperature for a specified time; and

removing the assembly of said outer layer, inner layer and embedded coil from the interior of said elongate rigid tube.

2. The method as recited in claim 1 wherein the gelling is accomplished by exposing the material to air flowing adjacent thereto at a rate of about 0.5 liters per minute.

3. The method as recited in claim 1 wherein the baking of each film takes place at a temperature of between 40*C and 70*C for a time of between one-half and 3 hours.

4. The method as recited in claim 1 when the final bakeout takes place at a temperature between 40*C and 70*C for about 8 hours.