Extremely thin-walled ePTFE

• US 8,087,923 B1
• Filed: 05/16/2008
• Issued: 01/03/2012
• Est. Priority Date: 05/18/2007
• Status: Active Grant

• Current Assignee: C.R. Bard, Inc. (Becton, Dickinson & Co)
• Original Assignee: C.R. Bard, Inc. (Becton, Dickinson & Co)
• Inventors: Bogert, David L.
• Primary Examiner(s): Gupta, Yogendra
• Assistant Examiner(s): Grun, Robert J
• Application Number:
  US12/122,518
• Time in Patent Office: 1,327 Days
• Field of Search: 264/323, 264/635, 264/515, 264/150, 425/392, 425/403, 425/380
• US Class Current: 425/468
• CPC Class Codes: B29C 48/022 characterised by the choice of material
• CPC Class Codes: B29C 48/09 Articles with cross-sections having partially or fully enclosed cavities, e.g. pipes or channels
• CPC Class Codes: B29C 48/32 with annular openings, e.g. for forming tubular articles
• CPC Class Codes: B29C 48/475 using pistons, accumulators or press rams
• CPC Class Codes: B29K 2027/18 PTFE, i.e. polytetrafluorethene , e.g. ePTFE, i.e. expanded polytetrafluorethene
• CPC Class Codes: B29K 2877/00 Use of PA, i.e. polyamides, e.g. polyesteramides or derivatives thereof, as mould material
• CPC Class Codes: B29L 2031/7542 Catheters

Abstract

An extrusion device is described herein, including an inventive die and mandrel that enable the production, using a conventional ram extruder, of strong coherent extremely thin-walled tubes having a wall thickness in the range of about 0.020 mm and about 0.080 mm.

Claims

1. An apparatus for extruding a tubular member, comprising:

a barrel having a bore extending from a proximal end to a distal end;

a die having a channel in communication with the bore, the channel including a generally cylindrical first section in communication with a die opening, the first section having a length in the range of about 0.010 inch to about 0.250 inch; and

a solid mandrel comprising a polyamide-imide material and having a distal section positioned in the channel, the polyamide-imide material flexing under pressure from an extrudate forced through the die to center the mandrel in the die.

2. The apparatus according to claim 1, wherein the mandrel comprises a length of hard but slightly flexible material selected from a group consisting of polyamide-imide, polyimide, phenolic, phenolic composites, polyphenylene sulfide, polymeric composites, Nitinol, and combinations thereof.

3. The apparatus according to claim 1, wherein the length of the die first section is in the range of about 0.020 inch to about 0.150 inch.

4. The apparatus according to claim 3, wherein the length of the die first section is about 0.030 inch.

5. The apparatus according to claim 3, wherein the length of the die first section is about 0.125 inch.

6. The apparatus according to claim 1, wherein the die opening has a diameter in the range of about 0.100 inch to about 0.500 inch.

7. The apparatus according to claim 1, wherein the channel includes a second section having a frusto-conical shape in communication with the die first section.

8. The apparatus according to claim 1, wherein the mandrel distal section terminates at about the die opening.

9. The apparatus according to claim 1, wherein the mandrel includes a proximal section with a diameter greater than a diameter of a distal section.

11. The apparatus according to claim 1, wherein a distance between an outer wall of the mandrel and a surface of the die first section is generally uniform and is in the range of about 0.020 mm and about 0.150 mm.

15. The extrusion device according to claim 8, wherein a mandrel distal face is approximately parallel to, and coincident with, a distal face of the die.

10. An extrusion device, comprising:

a barrel having a bore extending from a proximal end to a distal end;

a die having a channel in communication with the bore and a land length in the range of about 0.020 inch and about 0.150 inch; and

a solid polyamide-imide mandrel centering the mandrel in the die via flexion of the polyamide-imide under pressure from an extrudate forced through the die.

12. The apparatus according to claim 10, wherein the mandrel proximal section and distal section each have a generally cylindrical shape and are centrally positioned in the bore and the channel, respectively.

13. The extrusion device according to claim 10, wherein the mandrel includes a distal section that extends through the channel and terminates at a die opening.

14. The extrusion device according to claim 10, wherein the die land length is about 0.125 inch.

16. The extrusion device according to claim 13, wherein a mandrel distal face is approximately parallel to, and coincident with, a distal face of the die.