Highly crystalline polyethylene

Patent metadata

Field	Value
Publication number	US-9273189-B2
Application number	US-201313799593-A
Country	US
Kind code	B2
Filing date	Mar 13, 2013
Priority date	Aug 22, 2005
Publication date	Mar 1, 2016
Grant date	Mar 1, 2016

Abstract

The present invention relates to methods for making highly crystalline polymeric material, for example, highly crystalline cross-linked and not cross-linked ultra-high molecular weight polyethylene (UHMWPE). The invention also provides methods of making additive-doped highly crystalline polymeric material using high pressure and high temperature crystallization processes, medical implants made thereof, and materials used therein.

First claim

The invention claimed is:

1. A method of making a cross-linked and interlocked hybrid material for a medical device or implant, wherein the method comprises:
a) mixing a polymeric material with an antioxidant to form a polymeric blend;
b) compression molding of the polymeric blend to the counterface of second material, thereby forming an interlocked hybrid material having an interface between the polymeric blend and the second material;
c) elevating the temperature of the interlocked hybrid material to about 80° C. to below the melting point of the polymeric blend; and
d) irradiating the interlocked hybrid material from step (c) by electron beam radiation at the elevated temperature that is between about 80° C. to below the melting point of the polymeric blend, thereby forming cross-links in the polymeric blend and yielding a cross-linked and interlocked hybrid material for a medical device or implant, wherein: (i) the cross-linking strengthens the polymeric blend to minimize separation at the interface, (ii) the antioxidant provides resistance to post-irradiation oxidation, and (iii) the irradiation sterilizes the interface.

2. The method according to claim 1 , wherein the second material is porous so as to permit bony in-growth into the medical device or implant.

3. The method according to claim 2 , wherein the second material is metallic.

4. The method according to claim 2 , wherein the second material is non-metallic.

5. The method according to claim 1 , wherein the polymeric material is ultrahigh molecular weight polyethylene.

6. The method according to claim 1 , wherein the anti-oxidant is an α-tocopherol.

7. A method of making a medical device or implant comprising a cross-linked and interlocked hybrid material, wherein the method comprises:
a) mixing a polymeric material with an antioxidant to form a polymeric blend;
b) compression molding of the polymeric blend to the counterface of second material, thereby forming an interlocked hybrid material having an interface between the polymeric blend and the second material;
c) elevating the temperature of the interlocked hybrid material to about 80° C. to below the melting point of the polymeric blend;
d) irradiating the interlocked hybrid material from step (c) by electron beam radiation at the elevated temperature that is between about 80° C. to below the melting point of the polymeric blend, thereby forming cross-links in the polymeric blend and yielding a cross-linked and interlocked hybrid material for a medical device or implant, wherein: (i) the cross-linking strengthens the polymeric blend to minimize separation at the interface, (ii) the antioxidant provides resistance to post-irradiation oxidation, and (iii) the irradiation sterilizes the interface; and
e) machining the cross-linked and interlocked hybrid material to form the medical device or implant.

8. The method according to claim 7 , further comprising the step of e) sterilizing the medical device or implant.

9. The method according to claim 8 , wherein the sterilizing is by gas sterilization.

10. The method according to claim 8 , wherein the sterilizing is by ionizing radiation, wherein the antioxidant provides resistance to post-sterilization oxidation.

11. The method according to claim 7 , wherein the second material is porous so as to permit bony in-growth into the medical device or implant.

12. The method according to claim 11 , wherein the second material is metallic.

13. The method according to claim 11 , wherein the second material is non-metallic.

14. The method according to claim 7 , wherein the polymeric material is ultrahigh molecular weight polyethylene.

15. The method according to claim 7 , wherein the antioxidant is an α-tocopherol.

16. A method of making a cross-linked polymeric material for a medical device or implant, wherein the method comprises:
a) mixing a polymeric material with an antioxidant to form a polymeric blend;
b) elevating the temperature of the polymeric blend to about 80° C. to below the melting point of the polymeric blend; and
c) irradiating the polymeric blend from step (b) by electron beam radiation at the elevated temperature that is between about 80° C. to below the melting point of the polymeric blend, thereby forming cross-links in the polymeric blend and yielding a cross-linked polymeric blended material for a medical device or implant, wherein: (i) the cross-linking increases wear resistance, and (ii) the antioxidant provides resistance to post-irradiation oxidation.

17. The method according to claim 16 , wherein the polymeric material is ultrahigh molecular weight polyethylene.

18. The method according to claim 16 , wherein the antioxidant is an α-tocopherol.

19. The method according to claim 16 , wherein the polymeric blend is consolidated prior to the irradiation step.

20. A method of making a medical device or implant comprising a cross-linked polymeric material, wherein the method comprises:
a) mixing a polymeric material with an antioxidant to form a polymeric blend;
b) consolidating the polymeric blend;
c) elevating the temperature of the consolidated polymeric blend to about 80° C. to below the melting point of the polymeric blend;
d) irradiating the consolidated polymeric blend from step (c) by electron beam radiation at the elevated temperature that is between about 80° C. to below the melting point of the polymeric blend, thereby forming cross-links in the consolidated polymeric blend and yielding a cross-linked consolidated polymeric blended material for a medical device or implant, wherein: (i) the cross-linking increase wear resistance, and (ii) the antioxidant provides resistance to post-irradiation oxidation; and
e) machining the cross-linked consolidated polymeric material to form the medical device or implant.

21. The method according to claim 20 , further comprising the step of d) sterilizing the medical device or implant.

22. The method according to claim 21 , wherein the sterilizing is by gas sterilization.

23. The method according to claim 21 , wherein the sterilizing is by ionizing radiation, wherein the antioxidant provides resistance to post-sterilization oxidation.

24. The method according to claim 20 , wherein the polymeric material is ultrahigh molecular weight polyethylene.

25. The method according to claim 20 , wherein the antioxidant is an α-tocopherol.

26. The method of making a cross-linked and interlocked hybrid material for a medical device or implant, wherein the method comprises:
a) mixing a polymeric material with an antioxidant to form a polymeric blend;
b) compression molding of the polymeric blend to the counterface of second material, thereby forming an interlocked hybrid material having an interface between the polymeric blend and the second material;
c) elevating the temperature of the interlocked hybrid material to above room temperature to below 90° C.; and
d) irradiating the interlocked hybrid material from step (c) by electron beam radiation at the elevated temperature that is between above room temperature to below 90° C., thereby forming cross-links in the polymeric blend and yielding a cross-linked and interlocked hybrid material for a medical device or implant, wherein: (i) the cross-linking strengthens the polymeric blend to minimize separation at the interface, (ii) the antioxidant provides resistance to post-irradiation oxidation, and (iii) the irradiation steriliz

Assignees

• Gen Hospital Corp

Inventors

• Muratoglu Orhun K
• Oral Ebru

Classifications

• A61L27/16 Primary

  obtained by reactions only involving carbon-to-carbon unsaturated bonds · CPC title

• C08J3/20

  Compounding polymers with additives, e.g. colouring · CPC title

• C08L23/06

  Polyethylene · CPC title

• C08K5/1545

  Six-membered rings · CPC title

• C08J2323/06

  Polyethene · CPC title