High-strength multi-component suture

Patent metadata

Field	Value
Publication number	US-9986999-B2
Application number	US-201414471716-A
Country	US
Kind code	B2
Filing date	Aug 28, 2014
Priority date	Aug 29, 2013
Publication date	Jun 5, 2018
Grant date	Jun 5, 2018

Abstract

A method for making an expanded, and optionally multi-component and/or colored PTFE monofilament is disclosed. The method includes forming a first paste by mixing a PTFE powder with a hydrocarbon solvent; forming an extrusion preform by pressing the first paste into a form; curing the extrusion preform by exposing the extrusion preform to a first temperature for a first time duration; forming a green monofilament by extruding the first paste through a die; expanding the green monofilament by exposing the green monofilament to a second temperature for a second time duration, the second time duration occurring after the first time duration; stretching the green monofilament substantially along a longitudinal axis of the green monofilament, the stretching the green monofilament occurring after the expanding the green monofilament; and sintering the green monofilament after the stretching the green monofilament. The method may include doing all or some of the expanding, stretching and sintering steps simultaneously.

First claim

We claim:

1. A method for making an expanded polytetrafluoroethylene (PTFE) monofilament, the method comprising:
forming a first paste by mixing a PTFE powder with a hydrocarbon solvent, the first paste including less than about 16% of the hydrocarbon solvent by weight;
curing the first paste by exposing the first paste to a first temperature for a first time duration;
forming an extrusion preform by pressing the first paste into a form;
forming a green monofilament by extruding the first paste through a die;
expanding the green monofilament by exposing the green monofilament to a second temperature for a second time duration, the second time duration occurring after the first time duration;
stretching the green monofilament substantially along a longitudinal axis of the green monofilament, the stretching the green monofilament occurring after the expanding the green monofilament; and
sintering the green monofilament after the stretching the green monofilament,
wherein the expanding, stretching, and sintering are done in a continuous process.

2. The method of claim 1 , wherein the forming the first paste includes maintaining a mixture of the PTFE powder and the hydrocarbon solvent at a substantially constant temperature.

3. The method of claim 2 , wherein the substantially constant temperature is between about 50 degrees Fahrenheit and about 60 degrees Fahrenheit.

4. The method of claim 1 , wherein the first temperature is between about 68 degrees Fahrenheit to about 78 degrees Fahrenheit.

5. The method of claim 4 , wherein the first time duration is greater than about 24 hours.

6. The method of claim 1 , wherein the extrusion preform is substantially free from mechanical forces acting on a free surface of the extrusion preform during the first time duration.

7. The method of claim 1 , wherein the forming the extrusion preform includes imparting a pressure on the first paste between about 150 psi to about 190 psi.

8. The method of claim 1 , wherein the forming the extrusion preform includes:
forming a second paste,
disposing a divider in the form,
disposing the second paste in the form such that the second paste is in contact with a first side of the divider, the first side of the divider being opposite a second side of the divider that is in contact with the first paste.

9. The method of claim 8 , wherein a color of the first paste is different from a color of the second paste.

10. The method of claim 1 , wherein the second temperature ranges from about 520 degrees Fahrenheit to about 800 degrees Fahrenheit.

11. The method of claim 1 , wherein expanding the green monofilament includes exposing the green monofilament to an environment at the second temperature.

12. The method of claim 1 , wherein the second time duration is between about 0.1 and about 0.5 seconds.

13. The method of claim 1 , wherein the sintering the green monofilament includes exposing the green monofilament to a temperature greater than about 700° F. for a third time duration.

14. The method of claim 1 , wherein the forming the green monofilament includes imparting a pressure on the first paste between about 200 psi and about 400 psi.

15. The method of claim 8 , wherein the forming the green monofilament includes rotating an end of the green monofilament about a longitudinal axis of the green monofilament.

Assignees

• Teleflex Medical Inc

Inventors

• Olson James R
• Chen Jiunn-Yow
• Dinsmore Dean
• Wallace Jeffrey

Classifications

• B29C48/022

  characterised by the choice of material · CPC title

• D01F6/12

  from polymers of fluorinated hydrocarbons · CPC title

• D01D10/02

  Heat treatment (heating for finishing D02J13/00) · CPC title

• B29C48/0018

  combined with shaping by orienting, stretching or shrinking, e.g. film blowing (B29C48/0017 takes precedence) · CPC title

• D01F8/10

  with at least one other macromolecular compound obtained by reactions only involving carbon-to-carbon unsaturated bonds as constituent · CPC title