SEAL MEMBER

• US 20110156355A1
• Filed: 12/28/2009
• Published: 06/30/2011
• Est. Priority Date: 12/28/2009
• Status: Active Grant

• Current Assignee: Nissin Kogyo Company Limited (Hitachi, Ltd.), Schlumberger Technology Corporation (Schlumberger NV), Shinshu University National University Corporation
• Original Assignee: Nissin Kogyo Company Limited (Hitachi, Ltd.), Mefs Kabushiki Kaisha, Schlumberger Technology Corporation (Schlumberger NV), Shinshu University National University Corporation
• Inventors: ENDO, Morinobu, NOGUCHI, Toru, IINOU, Satoshi, INUKAI, Shigeki, ITO, Masaei, UEKI, Hiroyuki, MADHAVAN, Raghu
• Granted Patent: US 8,614,273 B2
• Time in Patent Office: Days
• US Class Current: 277/336
• CPC Class Codes: C08K 2201/011 Nanostructured additives
• CPC Class Codes: C08K 7/06 Elements
• CPC Class Codes: C08L 15/005 Hydrogenated nitrile rubber

Abstract

A seal member includes a hydrogenated acrylonitrile-butadiene rubber (HNBR) and carbon nanofibers. The seal member has a number of cycles to fracture of 7000 or more when subjected to a tensile fatigue test at a temperature of 70° C., a maximum tensile stress of 4 N/mm, and a frequency of 1 Hz. The seal member exhibits excellent abrasion resistance.

Claims

1. A seal member comprising a hydrogenated acrylonitrile-butadiene rubber (HNBR) and carbon nanofibers, the seal member having a number of cycles to fracture of 7000 or more when subjected to a tension fatigue test at a temperature of 70°

C., a maximum tensile stress of 4 N/mm, and a frequency of 1 Hz.

2. The seal member according to claim 1, the seal member including 10 to 60 parts by mass of the carbon nanofibers and 0 to 100 parts by mass of a filler having an average particle diameter of 5 to 100 nm based on 100 parts by mass of the hydrogenated acrylonitrile-butadiene rubber (HNBR),

the carbon nanofibers having an average diameter of 10 to 20 nm, and

the amount of the carbon nanofibers and the amount of the filler satisfying the following expressions (1) and (2),

Wt=0.1W1+W2 

 

(1)

20≦

Wt≦

60 

 

(2)

W1;

amount (parts by mass) of filler, and

W2;

amount (parts by mass) of carbon nanofibers.

3. The seal member according to claim 1, the seal member including 14 to 100 parts by mass of the carbon nanofibers and 0 to 60 parts by mass of a filler having an average particle diameter of 5 to 100 nm based on 100 parts by mass of the hydrogenated acrylonitrile-butadiene rubber (HNBR),

the carbon nanofibers having an average diameter of 60 to 110 nm, and

the amount of the carbon nanofibers and the amount of the filler satisfying the following expressions (3) and (4),

Wt=0.1W1+W2 

 

(3)

20≦

Wt≦

100 

 

(4)

W1;

amount (parts by mass) of filler, and

W2;

amount (parts by mass) of carbon nanofibers.

4. The seal member according to claim 1, the seal member having a number of cycles to fracture of 10,000 or more when subjected to a tensile fatigue test at a temperature of 70°

C., a maximum tensile stress of 4 N/mm, and a frequency of 1 Hz.

5. The seal member according to claim 1, the seal member having an abrasion loss Wa of 0.010 to 0.035 cm³/N·

m when subjected to a high-pressure abrasion test at 25°

C., the abrasion loss Wa satisfying the following expression (5),

Wa=(g₂−

g₁)/(P·

L·

d) 

 

(5)

g₁;

mass (g) of specimen before abrasion test,

g₂;

mass (g) of specimen after abrasion test,

P;

load (N) of weight,

L;

abrasion distance (m), and

d;

specific gravity (g/cm³).

6. The seal member according to claim 3, wherein the carbon nanofibers are carbon nanofibers subjected to an oxidation treatment.

7. The seal member according to claim 3, wherein the carbon nanofibers are carbon nanofibers subjected to a low-temperature heat treatment, and the amount of the carbon nanofibers is 54 to 100 parts by mass.

8. The seal member according to claim 1, the seal member being used for an oilfield apparatus.

9. The seal member according to claim 8, wherein the oilfield apparatus is a logging tool that performs a logging operation in a borehole.

10. The seal member according to claim 8, the seal member being an endless seal member that is disposed in the oilfield apparatus.

11. The seal member according to claim 8, the seal member being a stator of a fluid-driven motor that is disposed in the oilfield apparatus.

12. The seal member according to claim 11, wherein the fluid-driven motor is a mud motor.

13. The seal member according to claim 8, the seal member being a rotor of a fluid-driven motor that is disposed in the oilfield apparatus.

14. The seal member according to claim 13, wherein the fluid-driven motor is a mud motor.

15. The seal member according to claim 1, wherein the hydrogenated acrylonitrile-butadiene rubber (HNBR) has an acrylonitrile content of 30 to 50 mass %, a Mooney viscosity (ML₁₊₄100°

C.) center value of 50 to 100, and a hydrogenation rate of 90% or more.

16. The seal member according to claim 1, wherein the carbon nanofibers have an average rigidity of 3 to 12 before the carbon nanofibers are mixed into the hydrogenated acrylonitrile-butadiene rubber (HNBR), the rigidity being defined by Lx÷

D (Lx;

distance between adjacent defects of carbon nanofiber, D;

diameter of carbon nanofiber).

17. The seal member according to claim 2, wherein the filler is carbon black having an average particle diameter of 10 to 100 nm.

18. The seal member according to claim 3, wherein the filler is carbon black having an average particle diameter of 10 to 100 nm.

19. The seal member according to claim 2, wherein the filler is at least one material selected from silica, talc, and clay, and has an average particle diameter of 5 to 50 nm.

20. The seal member according to claim 3, wherein the filler is at least one material selected from silica, talc, and clay, and has an average particle diameter of 5 to 50 nm.

21. The seal member according to claim 1, the seal member having a ratio (Nb/Na) of a number of cycles to fracture Nb when subjected to a tension fatigue test at a temperature of 150°

C., a maximum tensile stress of 2.5 N/mm, and a frequency of 1 Hz to a number of cycles to fracture Na when subjected to a tension fatigue test at a temperature of 150°

C., a maximum tensile stress of 2 N/mm, and a frequency of 1 Hz, of 0.7 or more.