Method for manufacturing rubber composition

Patent metadata

Field	Value
Publication number	US-8969455-B2
Application number	US-201113876974-A
Country	US
Kind code	B2
Filing date	Oct 3, 2011
Priority date	Oct 1, 2010
Publication date	Mar 3, 2015
Grant date	Mar 3, 2015

Abstract

The present invention is a method for producing a rubber composition containing a rubber component (A) of at least one selected from natural rubbers and synthetic dienic rubbers, a filler containing an inorganic filler (B), a silane coupling agent (C), at least one vulcanization accelerator (D) selected from guanidines, sulfenamides and thiazoles, and an organic acid compound (E), wherein the rubber composition is kneaded in plural stages, the rubber component (A), all or a part of the inorganic filler (B), all or a part of the silane coupling agent (C), the vulcanization accelerator (D) and the organic acid compound (E) are kneaded in the first stage of kneading, and the number of molecules X of the organic acid compound (E) in the rubber composition in the first stage is in a relation of the following formula [1] relative to the number of molecules Y of the vulcanization accelerator (D) therein. The production method enables production of a rubber composition having a low-heat-generation property while successfully preventing the coupling function activity of the silane coupling agent from lowering.

0≦X≦1.5×Y  [1]

First claim

The invention claimed is:

1. A method for producing a rubber composition containing a rubber component (A) of at least one selected from natural rubbers and emulsion-polymerized dienic rubbers, a filler containing an inorganic filler (B), a silane coupling agent (C), at least one vulcanization accelerator (D) selected from guanidines, sulfenamides and thiazoles, and an organic acid compound (E) including the organic acid compound contained in the rubber component (A), wherein the rubber composition is kneaded in plural stages, the rubber component (A), all or a part of the inorganic filler (B), all or a part of the silane coupling agent (C), the vulcanization accelerator (D) and the organic acid compound (E) are kneaded in the first stage of kneading, and the number of molecules X of the organic acid compound (E) in the rubber composition in the first stage is in a relation of the following formula [1] relative to the number of molecules Y of the vulcanization accelerator (D) therein:
0≦X≦1.5×Y  [1].

2. The method for producing a rubber composition according to claim 1 , wherein the highest temperature of the rubber composition in the first stage is from 120 to 190° C.

3. The method for producing a rubber composition according to claim 1 , wherein the silane coupling agent (C) is at least one compound selected from a group consisting of compounds represented by the following general formulae (I) and (II):
[Chemical Formula 1]
(R 1 O) 3-p (R 2 ) p Si—R 3 —S a —R 3 —Si(OR 1 ) 3-r (R 2 ) r   (I)

[wherein, plural R 1 's may be the same or different, each representing a linear, cyclic or branched alkyl group having from 1 to 8 carbon atoms, a linear or branched alkoxylalkyl group having from 2 to 8 carbon atoms, or a hydrogen atom; plural R 2 's may be the same or different, each representing a linear, cyclic or branched alkyl group having from 1 to 8 carbon atoms; plural R 3 's may be the same or different, each representing a linear or branched alkylene group having from 1 to 8 carbon atoms; a indicates from 2 to 6 as a mean value; p and r may be the same or different, each indicating from 0 to 3 as a mean value, provided that both p and r are not 3 at the same time];
[Chemical Formula 2]
(R 4 O) 3-s (R 5 ) s Si—R 6 —S k —R 7 —S k —R 6 —Si(OR 4 ) 3-t (R 5 ) t   (II)

[wherein plural R 4 's may be the same or different, each representing a linear, cyclic or branched alkyl group having from 1 to 8 carbon atoms, a linear or branched alkoxylalkyl group having from 2 to 8 carbon atoms, or a hydrogen atom; plural R 5 's may be the same or different, each representing a linear, cyclic or branched alkyl group having from 1 to 8 carbon atoms; plural R 6 's may be the same or different, each representing a linear or branched alkylene group having from 1 to 8 carbon atoms; R 7 represents a divalent group of a general formula (—S—R 8 —S—), (—R 9 —S m1 —R 10 ) or (—R 11 —S m2 —R 12 —S m3 —R 13 —) (where R 8 to R 13 each represents a divalent hydrocarbon group, a divalent aromatic group or a divalent organic group containing a hetero element except sulfur and oxygen, having from 1 to 20 carbon atoms; m1, m2 and m3 may be the same or different, each indicating from 1 to less than 4 as a mean value); plural k's may be the same or different, each indicating from 1 to 6 as a mean value; s and t each indicate from 0 to 3 as a mean value, provided that both s and t are not 3 at the same time].

4. The method for producing a rubber composition according to claim 3 , the silane coupling agent (C) is a compound represented by the general formula (I).

5. The method for producing a rubber composition according to claim 1 , wherein the inorganic filler (B) is silica.

6. The method for producing a rubber composition according to claim 1 , wherein the inorganic filler (B) accounts for at least 30% by mass of the filler.

7. The method for producing a rubber composition according to claim 1 , wherein the number of molecules of the vulcanization accelerator (D) in the rubber composition in the first stage of kneading is from 0.1 to 1.0 time the number of molecules of the silane coupling agent (C) therein.

8. The method for producing a rubber composition according to claim 1 , wherein the guanidine is at least one compound selected from 1,3-diphenylguanidine, 1,3-di-o-tolylguanidine and 1-o-tolylbiguanide.

9. The method for producing a rubber composition according to claim 1 , wherein the sulfenamide is at least one compound selected from N-cyclohexyl-2-benzothiazolylsulfenamide and N-tert-butyl-2-benzothiazolylsulfenamide.

10. The method for producing a rubber composition according to claim 1 , wherein the thiazol is at least one compound selected from 2-mercaptobenzothiazole and di-2-benzothiazolyl disulfide.

11. The method for producing a rubber composition according to claim 1 , wherein at least 50 mol % of the organic acid compound in the rubber composition in the first stage of kneading is stearic acid.

12. The method for producing a rubber composition according to claim 1 , wherein the rubber component (A) contains at least one selected from emulsion-polymerized styrene-butadiene copolymer and natural rubber, and at least 50 mol % of the organic acid compound contained in the rubber composition in the first stage of kneading is at least one compound selected from rosin acids and fatty acids contained in at least one selected from the emulsion-polymerized styrene butadiene copolymer and the natural rubber.

13. The method for producing a rubber composition according to claim 1 , wherein in the first stage, the rubber component (A), all or a part of the inorganic filler (B) and all or a part of the silane coupling agent (C) are kneaded, and then the vulcanization accelerator (D) is added thereto and further kneaded.

14. A method for producing a rubber composition containing solution-polymerized dienic rubbers as the sole rubber component (A), a filler containing an inorganic filler (B), a silane coupling agent (C), at least one vulcanization accelerator (D) selected from guanidines, sulfenamides and thiazoles, and optionally an organic acid compound (E), wherein the rubber composition is kneaded in plural stages, the rubber component (A), all or a part of the inorganic filler (B), all or a part of the silane coupling agent (C) and the vulcanization accelerator (D) are kneaded in the first stage of kneading, and the number of molecules X of the organic acid compound (E) in the rubber composition in the first stage is in a relation of the following formula [1] relative to the number of molecules Y of the vulcanization accelerator (D) therein:
0≦X≦(3.5/4.7)×Y  [1],

provided that Y is not 0.

15. The method for producing a rubber composition according to claim 14 , wherein the highest temperature of the rubber composition in the first stage is from 120 to 190° C.

16. The method for producing a rubber composition according to claim 14 , wherein the silane coupling agent (C) is at least one compound selected from a group consisting of compounds represented by the following general formulae (I) and (II):
[Chemical Formula 1]
(R 1 O) 3-p (R 2 ) p Si—R 3 —S a —R 3 —Si(OR 1 ) 3-r (R 2 ) r   (I)

[wherein, plural R 1 's may be the same or different, each representing a linear, cyclic or branched alkyl group having from 1 to 8 carbon atoms, a linear or branched alkoxylalkyl group having from 2 to 8 carbon atoms, or a hydrogen atom; plural R 2 's may be the same or different, each representing a linear, cyclic or branched alkyl group having from 1 to 8 carbon atoms; plural R 3 's may be the same or different, each represent

Assignees

• Katou Seiichi
• Horie Satoshi
• Bridgestone Corp

Inventors

• Katou Seiichi
• Horie Satoshi

Classifications

• C08K3/36 Primary

  Silica · CPC title

• C08L7/00

  Compositions of natural rubber · CPC title

• C08L21/00 Primary

  Compositions of unspecified rubbers · CPC title

• C08K5/44

  Sulfenamides · CPC title

• C08K5/31

  Guanidine; Derivatives thereof · CPC title