Cross-linked rubber and production method therefor

Patent metadata

Field	Value
Publication number	US-11084910-B2
Application number	US-201816618231-A
Country	US
Kind code	B2
Filing date	Jun 6, 2018
Priority date	Jun 6, 2017
Publication date	Aug 10, 2021
Grant date	Aug 10, 2021

Abstract

Provided is a cross-linked rubber that can improve long-term sealing properties of a seal member in high-temperature and high-pressure environments. The cross-linked rubber is obtained through cross-linking of a cross-linkable rubber composition containing a fluororubber, carbon black, one or more carbon nanotubes, and an organic peroxide cross-linker, and has a 50% modulus of 5 MPa or more, a compression set (230° C., 500 hours) of 80% or less, and a rate of change of elongation at break between before and after a heat aging test (230° C., 72 hours) of not less than −10% and not more than 10%.

First claim

The invention claimed is:

1. A cross-linked rubber obtained through cross-linking of a cross-linkable rubber composition comprising a fluororubber, carbon black, one or more carbon nanotubes, and an organic peroxide cross-linker, wherein
the cross-linked rubber has:
a 50% modulus of 5 MPa or more;
a compression set under conditions of 230° C. and 500 hours of 80% or less; and
a rate of change of elongation at break between before and after a heat aging test under conditions of 230° C. and 72 hours of not less than 10% and not more than 10%.

2. The cross-linked rubber according to claim 1 , wherein the carbon black includes coal having a carbon content of not less than 60 mass % and not more than 90 mass %.

3. The cross-linked rubber according to claim 2 , wherein the coal is contained in a proportion of not less than 0.5 parts by mass and less than 5 parts by mass per 100 parts by mass of the fluororubber.

4. The cross-linked rubber according to claim 2 , wherein the coal is bituminous coal.

5. The cross-linked rubber according to claim 1 , having a breaking strength of 23 MPa or more.

6. The cross-linked rubber according to claim 1 , wherein the fluororubber has a glass-transition temperature of −7° C. or lower.

7. The cross-linked rubber according to claim 1 , wherein the carbon nanotubes are contained in a proportion of not less than 0.4 parts by mass and less than 10 parts by mass per 100 parts by mass of the fluororubber.

8. A cross-linked rubber production method for producing the cross-linked rubber according to claim 1 , comprising:
a step (A) of obtaining a composite containing a fluororubber and one or more carbon nanotubes that are dispersed in the fluororubber;
a step (B) of kneading the composite, carbon black, and an organic peroxide cross-linker to obtain a cross-linkable rubber composition; and
a step (C) of shaping and cross-linking the cross-linkable rubber composition to obtain a cross-linked rubber, wherein
the composite is obtained in the step (A) by performing wet dispersing treatment of a mixture containing a fluororubber, one or more carbon nanotubes, and an organic solvent and subsequently removing the organic solvent.

9. The cross-linked rubber production method according to claim 8 , wherein removal of the organic solvent in the step (A) is performed by thin film drying.

10. The cross-linked rubber production method according to claim 8 , wherein
the step (B) includes a step (B1) of kneading the composite and the carbon black to obtain a precompound and a step (B2) of kneading the precompound and the organic peroxide cross-linker to obtain the cross-linkable rubber composition, and
kneading in the step (B2) is performed such that kneaded material does not reach a temperature of 90° C. or higher.

11. The cross-linked rubber production method according to claim 8 , wherein the wet dispersing treatment of the mixture in the step (A) is performed using a jet mill.

12. The cross-linked rubber production method according to claim 8 , wherein kneading in the step (B) is performed using an internal kneader.

13. The cross-linked rubber production method according to claim 12 , wherein the internal kneader is a pressing-type kneader.

Assignees

• Zeon Corp
• Aist

Inventors

• Komatsu Masaaki
• Komatsu Anna
• ATA Seisuke
• Hata Kenji
• Tomonoh Shigeki

Classifications

• B29B7/02

  non-continuous, with mechanical mixing or kneading devices, i.e. batch type · CPC title

• C08K5/14

  Peroxides · CPC title

• C08J3/24 Primary

  Crosslinking, e.g. vulcanising, of macromolecules (mechanical aspects B29C35/00; crosslinking agents C08K) · CPC title

• C08J3/20

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

• B29B7/28

  for measuring, controlling or regulating, e.g. viscosity control {(B29B7/242 takes precedence)} · CPC title