Light weight seal cap

• US 10,174,781 B2
• Filed: 04/15/2014
• Issued: 01/08/2019
• Est. Priority Date: 04/15/2013
• Status: Active Grant

• Current Assignee: 3M Innovative Properties Company (3M Company)
• Original Assignee: 3M Innovative Properties Company (3M Company)
• Inventors: Zook, Jonathan D., Hebert, Larry S., Swan, Michael D., Ye, Sheng, DeMoss, Susan E., Wright, Robin E.
• Primary Examiner(s): Saether, Flemming
• Application Number:
  US14/783,916
• Publication Number:
  US 20160069378A1
• Time in Patent Office: 1,729 Days
• Field of Search: 411377
• CPC Class Codes: B64D 45/02 Lightning protectors; Static dischargers in general H01T
• CPC Class Codes: F16B 37/14 Cap nuts; Nut caps or bolt caps

Abstract

The present disclosure provides methods and articles useful in sealing fasteners, including seal caps and methods of their use, and in particular light weight seal caps having higher dielectric breakdown strength, lower weight, and/or lower wall thick-ness. In some embodiments, the seal caps according to the present invention are made of a material having a dielectric breakdown strength of greater than 1.0 kV/mm, in some embodiments greater than 15.0 kV/mm, and in some embodiments greater than 50.0 kV/mm. In some embodiments, the seal caps according to the present invention are thin-walled, having an average wall thickness of less than 1.5 mm and in some embodiments less than less than 0.5 mm In some embodiments, the seal cap comprises a polyurethane polymer, a polythioether polymer, a polysulfide polymer, a fluorinated thermoplastic polymer, a THV polymer, a fluorinated thermo-set polymer, an engineering thermoplastic, and/or a PEEK polymer.

Claims

1. A method of protecting a fastener comprising the steps of:

a) providing a fastener;

b) providing a seal cap which defines an interior, wherein the seal cap comprises a material having a dielectric breakdown strength of greater than 30.0 kV/mm, and wherein the seal cap has an average wall thickness of less than 0.5 mm;

c) applying an uncured sealant to the interior of the seal cap or to the fastener or to both; and

d) positioning the seal cap over the fastener such that at least a portion of the fastener resides in the interior of the seal cap.

2. The method according to claim 1 wherein the seal cap comprises a material having a dielectric breakdown strength of greater than 40.0 kV/mm.

3. The method according to claim 1 wherein the seal cap comprises a material having a dielectric breakdown strength of greater than 50.0 kV/mm.

4. The method according to claim 1 wherein the seal cap comprises a fluorinated thermoplastic polymer.

5. The method according to claim 1 wherein the seal cap comprises a fluorinated thermoset polymer.

6. The method according to claim 1 wherein the seal cap comprises an engineering thermoplastic.

7. The method according to claim 1 wherein the seal cap comprises a PEEK polymer.

8. The method according to claim 1 wherein the sealant comprises a polythioether polymer.

9. The method according to claim 1 wherein the seal cap comprises a THV polymer.

10. A method of protecting a fastener comprising the steps of:

f) providing a fastener;

g) providing a seal cap which defines an interior, wherein the seal cap comprises a material having a dielectric breakdown strength of greater than 30.0 kV/mm, wherein the seal cap has an average wall thickness of less than 0.5 mm, and wherein the interior of the seal cap contains a quantity of an uncured sealant; and

h) positioning the seal cap over the fastener such that at least a portion of the fastener resides in the interior of the seal cap.

11. The method according to claim 10 additionally comprising the step of:

j) curing the sealant.

12. The method according to claim 11 wherein the seal cap is optically translucent and wherein said step of curing the sealant comprises application of actinic radiation to the sealant through the seal cap.

13. A protected fastener construction comprising:

q) a fastener;

r) a seal cap which defines an interior; and

s) a cured sealant;

wherein the seal cap comprises a material having a dielectric breakdown strength of greater than 30.0 kV/mm, and wherein the seal cap has an average wall thickness of less than 0.5 mm;

wherein the seal cap is positioned over the fastener such that at least a portion of the fastener resides in the interior of the seal cap; and

wherein the interior of the seal cap additionally contains the cured sealant which binds the seal cap to the fastener.

14. The protected fastener construction according to claim 13 wherein the seal cap is translucent.

15. The protected fastener construction according to claim 13 wherein the seal cap is visibly transparent.

16. The protected fastener construction according to claim 13 wherein the seal cap comprises a material having a dielectric breakdown strength of greater than 40.0 kV/mm.

17. The protected fastener construction according to claim 13 wherein the seal cap comprises a material having a dielectric breakdown strength of greater than 50.0 kV/mm.

18. The protected fastener construction according to claim 13 wherein the seal cap comprises a fluorinated thermoplastic polymer.

19. The protected fastener construction according to claim 13 wherein the seal cap comprises a fluorinated thermoset polymer.

20. The protected fastener construction according to claim 13 wherein the seal cap comprises an engineering thermoplastic.

21. The protected fastener construction according to claim 13 wherein the seal cap comprises a THV polymer.

22. An application-ready seal cap comprising:

v) a seal cap which defines an interior; and

w) a quantity of an uncured sealant;

wherein the seal cap comprises a material having a dielectric breakdown strength of greater than 30.0 kV/mm, and wherein the seal cap has an average wall thickness of less than 0.5 mm; and

wherein the interior of the seal cap contains the quantity of uncured sealant.

23. The application-ready seal cap according to claim 22 wherein the seal cap is translucent.

24. The application-ready seal cap according to claim 22 wherein the seal cap is optically transparent.

25. The application-ready seal cap according to claim 22 wherein the seal cap comprises a material having a dielectric breakdown strength of greater than 40.0 kV/mm.

26. The application-ready seal cap according to claim 22 wherein the seal cap comprises a material having a dielectric breakdown strength of greater than 50.0 kV/mm.

27. The application-ready seal cap according to claim 22 wherein the seal cap comprises a fluorinated thermoplastic polymer.

28. The application-ready seal cap according to claim 22 wherein the seal cap comprises a fluorinated thermoset polymer.

29. The application-ready seal cap according to claim 22 wherein the seal cap comprises an engineering thermoplastic.

30. The application-ready seal cap according to claim 22 wherein the seal cap comprises a THV polymer.

31. A seal cap for protection of a fastener comprising a material having a dielectric breakdown strength of greater than 30.0 kV/mm having an average wall thickness of less than 0.5 mm.

32. The seal cap according to claim 31 which is translucent.

33. The seal cap according to claim 31 which is optically transparent.

34. The seal cap according to claim 31 which comprises a material having a dielectric breakdown strength of greater than 40.0 kV/mm.

35. The seal cap according to claim 31 which comprises a material having a dielectric breakdown strength of greater than 50.0 kV/mm.

36. The seal cap according to claim 31 comprising a fluorinated thermoplastic polymer.

37. The seal cap according to claim 31 comprising a fluorinated thermoset polymer.

38. The seal cap according to claim 31 comprising an engineering thermoplastic.

39. The seal cap according to claim 31 comprising a PEEK polymer.

40. The seal cap according to claim 31 comprising a THV polymer.

41. A method of protecting a fastener comprising the steps of:

a) providing a fastener;

b) providing a seal cap which defines an interior, wherein the seal cap comprises a material having a dielectric breakdown strength of greater than 30.0 kV/mm, and wherein the seal cap has an average wall thickness of less than 1.5 mm;

c) applying an uncured sealant to the interior of the seal cap or to the fastener or to both; and

d) positioning the seal cap over the fastener such that at least a portion of the fastener resides in the interior of the seal cap;

wherein the seal cap comprises a THV polymer.

42. A protected fastener construction comprising:

q) a fastener;

r) a seal cap which defines an interior; and

s) a cured sealant;

wherein the seal cap comprises a material having a dielectric breakdown strength of greater than 30.0 kV/mm;

wherein the seal cap has an average wall thickness of less than 1.5 mm;

wherein the seal cap is positioned over the fastener such that at least a portion of the fastener resides in the interior of the seal cap;

wherein the interior of the seal cap additionally contains the cured sealant which binds the seal cap to the fastener; and

wherein the seal cap comprises a THV polymer.

43. An application-ready seal cap comprising:

v) a seal cap which defines an interior; and

w) a quantity of an uncured sealant;

wherein the seal cap comprises a material having a dielectric breakdown strength of greater than 30.0 kV/mm;

wherein the seal cap has an average wall thickness of less than 1.5 mm;

wherein the interior of the seal cap contains the quantity of uncured sealant; and

wherein the seal cap comprises a THV polymer.

44. A seal cap for protection of a fastener comprising a material having a dielectric breakdown strength of greater than 30.0 kV/mm having an average wall thickness of less than 1.5 mm;

the seal cap comprising a THV polymer.