Fluororubber composition and method for producing same

Patent metadata

Field	Value
Publication number	US-9403954-B2
Application number	US-201314346156-A
Country	US
Kind code	B2
Filing date	Jan 18, 2013
Priority date	Jan 20, 2012
Publication date	Aug 2, 2016
Grant date	Aug 2, 2016

Abstract

The invention provides a fluororubber composition able to produce a crosslinked fluororubber article that exhibits not only heat resistance, but also excellent mechanical properties at high temperatures, and a method for producing same. The fluororubber composition contains: a fluororubber (A); and carbon black (B), wherein when the aforementioned fluororubber composition is immersed for 160 hours in an extraction solvent of acetone and hexane at an acetone:hexane mass ratio of 42.29:57.71 at 40° C. and an extraction residue that is not extracted and remains as a solid is separated from the aforementioned extraction solvent and dried and then the dry weight of the extraction residue is measured, the quantity of a solvent-insoluble polymer is not lower than 5%.

First claim

The invention claimed is:

1. A fluororubber composition comprising: a fluororubber (A); and carbon black (B); and a crosslinking agent (C) and/or a crosslinking accelerator (D), wherein
when the fluororubber composition in an uncrosslinked state is immersed for 160 hours in an extraction solvent of acetone and hexane at an acetone:hexane mass ratio of 42.29:57.71 at 40° C. and extraction residue that is not extracted and remains as a solid is separated from the aforementioned extraction solvent and dried and then the dry weight of the extraction residue is measured, the quantity of a solvent-insoluble polymer, as calculated using the expression below, is not lower than 5%:

Quantity
⁢

⁢
of
⁢

⁢
solvent
⁢

-

⁢
insoluble
⁢

⁢
polymer
⁢

⁢

(
%
)

=

w
′

×

Φ
p
′

w
×

Φ
p

×
100

[

Expression
⁢

⁢
1

]

(where, w is an initial weight (g) of the fluororubber composition which is immersed in the extraction solvent, w′ is a dry weight (g) of the extraction residue, φ p is an initial weight fraction of the fluororubber (A) contained in the fluororubber composition which is immersed in the extraction solvent relative to the fluororubber composition, and φ p ′ is a weight fraction of the fluororubber (A) contained in the extraction residue relative to the extraction residue).

2. The fluororubber composition according to claim 1 , wherein the fluororubber (A) is a vinylidene fluoride rubber.

3. The fluororubber composition according to claim 1 , wherein the fluororubber (A) is a bipolymer selected from among the group consisting of a copolymer of vinylidene fluoride and hexafluoropropylene, a copolymer of vinylidene fluoride and a fluorine-containing monomer represented by general formula (2) and a copolymer of vinylidene fluoride and a perfluoro (alkyl vinyl ether):
Here, general formula (2) being
CH 2 ═CFR f   (2)

(where, Rf is a straight chain or branched fluoroalkyl group having 1 to 12 carbon atoms).

4. The fluororubber composition according to claim 1 , which contains 5 to 65 parts by mass of the carbon black (B) relative to 100 parts by mass of the fluororubber (A).

5. The fluororubber composition according to claim 1 , wherein the carbon black (B) has a nitrogen adsorption specific surface area (N 2 SA) of 25 to 180 m 2 /g and a dibutyl phthalate (DBP) absorption number of 45 to 180 ml/100 g.

6. A method for producing a fluororubber composition, the method comprising:
a step (1-1) of mixing the fluororubber (A) and the carbon black (B) by means of an internal mixer until the maximum temperature reaches 80 to 220° C. so as to obtain an intermediate composition;
a step (1-2) of cooling the intermediate composition to a temperature of lower than 50° C.; and
a step (2-1) of mixing the cooled intermediate composition until the maximum temperature reaches not lower than 10° C. but lower than 80° C. so as to obtain a fluororubber composition.

7. The method for producing a fluororubber composition according to claim 6 , wherein the fluororubber (A) is a vinylidene fluoride rubber.

8. The method for producing a fluororubber composition according to claim 6 , wherein 5 to 65 parts by mass of the carbon black (B) is mixed with 100 parts by mass of the fluororubber (A) in the step (1-1).

9. The method for producing a fluororubber composition according to claim 6 , wherein the carbon black (B) has a nitrogen adsorption specific surface area (N 2 SA) of 25 to 180 m 2 /g and a dibutyl phthalate (DBP) absorption number of 45 to 180 ml/100 g.

10. The method for producing a fluororubber composition according to claim 6 , wherein a crosslinking agent (C) and/or a crosslinking accelerator (D) is further mixed in the step (1-1).

11. The method for producing a fluororubber composition according to claim 6 , further comprising a step of mixing a crosslinking agent (C) and/or a crosslinking accelerator (D) with the fluororubber composition obtained in the step (2-1).

12. The fluororubber composition according to claim 1 , wherein the fluororubber composition comprises the crosslinking agent (C), the crosslinking agent (C) being a crosslinking agent for a peroxide crosslinking system.

13. The fluororubber composition according to claim 1 , wherein the fluororubber composition comprises the crosslinking agent (C), the crosslinking agent (C) being a crosslinking agent for a peroxide crosslinking system which generates peroxy radicals in the presence of heat or an oxidation-reduction system.

Assignees

• Daikin Ind Ltd

Inventors

• Ota Daisuke
• Ueda Akinori
• Kadowaki Yuu
• Taeda Mayuko
• Kitaichi Masanori
• Doi Michiko
• Yamamura Kazuhiro
• Fukuoka Shoji

Classifications

• C08J2315/02

  Rubber derivatives containing halogen · CPC title

• B29B7/82

  Heating or cooling · CPC title

• C08K3/04

  Carbon · CPC title

• C08J2327/16

  Homopolymers or copolymers of vinylidene fluoride · CPC title

• C08J3/203 Primary

  Solid polymers with solid and/or liquid additives · CPC title