Radially expandable polytetrafluoroethylene
First Claim
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1. A method for producing a porous tube consisting essentially of highly crystalline polytetrafluoroethylene polymer, comprising the steps of (a) extruding a lubricant—
- polytetrafluoroethylene resin blend to form a tubing having a longitudinal axis, a primary inner diameter, and a primary length;
(b) heating the tubing to remove the lubricant;
(c) stretching the tubing along said longitudinal axis to produce an elongated tubing having a secondary length greater than said primary length;
(d) restraining said elongate tubing to prevent said elongate tubing from longitudinally contracting during sintering;
(e) sintering said elongated tubing to produce a sintered tubing having a length substantially equivalent to said secondary length;
(f) radially expanding said sintered tubing to produce radially expanded tubing have an expanded inner diameter greater than said primary inner diameter; and
, (g) sintering said radially expanded tubing to contract said radially expanded tubing and produce a tubing having an inner diameter substantially equivalent to said primary inner diameter.
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Accused Products
Abstract
Extruded, stretched, sintered tubular PTFE materials are produced which are suited for use in the medical field as liners and covers for expandable stents. The PTFE materials have an unusually low REC (Radial Expansion Coefficient) and RER (Radial Expansion Ratio).
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Citations
41 Claims
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1. A method for producing a porous tube consisting essentially of highly crystalline polytetrafluoroethylene polymer, comprising the steps of
(a) extruding a lubricant— - polytetrafluoroethylene resin blend to form a tubing having a longitudinal axis, a primary inner diameter, and a primary length;
(b) heating the tubing to remove the lubricant;
(c) stretching the tubing along said longitudinal axis to produce an elongated tubing having a secondary length greater than said primary length;
(d) restraining said elongate tubing to prevent said elongate tubing from longitudinally contracting during sintering;
(e) sintering said elongated tubing to produce a sintered tubing having a length substantially equivalent to said secondary length;
(f) radially expanding said sintered tubing to produce radially expanded tubing have an expanded inner diameter greater than said primary inner diameter; and
,(g) sintering said radially expanded tubing to contract said radially expanded tubing and produce a tubing having an inner diameter substantially equivalent to said primary inner diameter. - View Dependent Claims (2, 3)
- polytetrafluoroethylene resin blend to form a tubing having a longitudinal axis, a primary inner diameter, and a primary length;
- 4. A porous material consisting essentially of highly crystalline polytetrafluoroethylene polymer, which material has a microstructure characterized by nodes interconnected by fibrils and has been radially pre-dilated.
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11. A porous material consisting essentially of highly crystalline polytetrafluoroethylene polymer, which material has a microstructure characterized by nodes interconnected by fibrils;
- has a Radial Expansion Coefficient (REC) of less than 2.0; and
has been radially pre-dilated. - View Dependent Claims (20, 21)
- has a Radial Expansion Coefficient (REC) of less than 2.0; and
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12. A porous material consisting essentially of highly crystalline polytetrafluoroethylene polymer, which material has a microstructure characterized by nodes interconnected by fibrils;
- has a Radial Expansion Coefficient (REC) of less than 1.7; and
has been radially pre-dilated. - View Dependent Claims (22, 23)
- has a Radial Expansion Coefficient (REC) of less than 1.7; and
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13. A porous material consisting essentially of highly crystalline polytetrafluoroethylene polymer, which material has a microstructure characterized by nodes interconnected by fibrils;
- has a Radial Expansion Coefficient (REC) of less than 1.5; and
has been radially pre-dilated. - View Dependent Claims (24, 25)
- has a Radial Expansion Coefficient (REC) of less than 1.5; and
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14. A porous material consisting essentially of highly crystalline polytetrafluoroethylene polymer, which material has a microstructure characterized by nodes interconnected by fibrils;
- has a Radial Expansion Coefficient (REC) of less than 1.0; and
, has been radially pre-dilated. - View Dependent Claims (26, 27)
- has a Radial Expansion Coefficient (REC) of less than 1.0; and
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15. A porous material consisting essentially of highly crystalline polytetrafluoroethylene polymer, which material has a microstructure characterized by nodes interconnected by fibrils;
- has a Radial Expansion Ratio (RER) of less than 30; and
, has been radially pre-dilated. - View Dependent Claims (28, 29)
- has a Radial Expansion Ratio (RER) of less than 30; and
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16. A porous material consisting essentially of highly crystalline polytetrafluoroethylene polymer, which material has a microstructure characterized by nodes interconnected by fibrils;
- has a Radial Expansion Ratio (RER) of less than 20; and
, has been radially pre-dilated. - View Dependent Claims (30, 31)
- has a Radial Expansion Ratio (RER) of less than 20; and
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17. A porous material consisting essentially of highly crystalline polytetrafluoroethylene polymer, which material has a microstructure characterized by nodes interconnected by fibrils;
- has a Radial Expansion Ratio (RER) of less than 10; and
, has been radially pre-dilated. - View Dependent Claims (32, 33)
- has a Radial Expansion Ratio (RER) of less than 10; and
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18. A porous material consisting essentially of highly crystalline polytetrafluoroethylene polymer, which material has a microstructure characterized by nodes interconnected by fibrils;
- has a Radial Expansion Ratio (RER) of less than 5; and
, has been radially pre-dilated. - View Dependent Claims (34, 35)
- has a Radial Expansion Ratio (RER) of less than 5; and
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19. A porous material consisting essentially of highly crystalline polytetrafluoroethylene polymer, which material has a microstructure characterized by nodes interconnected by fibrils;
- has a ratio of Reduction Ration (RR) to Lubricant Level (LL) of less than 5; and
, has been radially pre-dilated. - View Dependent Claims (36, 37)
- has a ratio of Reduction Ration (RR) to Lubricant Level (LL) of less than 5; and
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38. A porous material consisting essentially of highly crystalline polytetrafluoroethylene polymer, which material has a microstructure characterized by nodes interconnected by fibrils;
- has a structural integrity which is retained until said material is radially expanded by more than 50%; and
has been radially pre-dilated.
- has a structural integrity which is retained until said material is radially expanded by more than 50%; and
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39. A porous material consisting essentially of highly crystalline polytetrafluoroethylene polymer, which material has a microstructure characterized by nodes interconnected by fibrils;
- has a structural integrity which is retained until said material is radially expanded by more than 75%; and
, has been radially pre-dilated.
- has a structural integrity which is retained until said material is radially expanded by more than 75%; and
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40. A porous material consisting essentially of highly crystalline polytetrafluoroethylene polymer, which material has a microstructure characterized by nodes interconnected by fibrils;
- has a structural integrity which is retained until said material is radially expanded by more than 100%; and
, has been radially pre-dilated.
- has a structural integrity which is retained until said material is radially expanded by more than 100%; and
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41. A porous material consisting essentially of highly crystalline polytetrafluoroethylene polymer, which material has a microstructure characterized by nodes interconnected by fibrils;
- has a structural integrity which is retained until said material is radially expanded by more than 150%; and
has been radially pre-dilated.
- has a structural integrity which is retained until said material is radially expanded by more than 150%; and
Specification