WO2013151072A1

WO2013151072A1 - Process for producing rubber composition

Info

Publication number: WO2013151072A1
Application number: PCT/JP2013/060132
Authority: WO
Inventors: 加藤　誠一
Original assignee: 株式会社ブリヂストン
Priority date: 2012-04-03
Filing date: 2013-04-02
Publication date: 2013-10-10

Abstract

The present invention provides a process for producing a rubber composition obtained by mixing a rubber ingredient (A) comprising at least one rubber selected from natural rubber and synthetic diene rubbers, a filler comprising carbon black (B), and at least one compound (C) selected from vulcanization accelerators, the process comprising a plurality of kneading stages: in the first stage (X) of kneading, the rubber ingredient (A) and all or some of the carbon black (B) are kneaded together; and in a stage prior to the final stage of kneading, the at least one compound (C) selected from vulcanization accelerators is added and kneaded. With this rubber composition, the low heat buildup can be improved.

Description

Method for producing rubber composition

The present invention relates to a method for producing a rubber composition containing carbon black that improves low heat build-up.

In recent years, there has been an increasing demand for fuel efficiency reduction of automobiles in connection with the global movement of regulation of carbon dioxide emissions due to increasing interest in environmental problems. In order to meet such demands, tires are required to reduce rolling resistance. As a technique for reducing the rolling resistance of the tire, a technique of applying a low heat-generating rubber composition to the tire can be mentioned.
As a method for obtaining a rubber composition having low exothermicity, in the case of a synthetic diene rubber, a method of using a polymer having enhanced affinity for carbon black and silica as the rubber composition (see, for example, Patent Document 1) ). In the case of natural rubber, a method of blending highly reactive carbon black with a modified natural rubber obtained by modifying natural rubber (for example, see Patent Document 2).
According to Patent Documents 1 and 2, the exothermic property of the rubber composition can be lowered by increasing the affinity between the filler such as carbon black and the rubber component. Thereby, a tire with low hysteresis loss can be obtained.
However, as the fuel efficiency of automobiles further advances, further improvements in tires with low heat generation have been desired.

JP 2003-514079 A International Publication No. 2007/066669

An object of the present invention is to provide a method for producing a rubber composition capable of improving low heat build-up.

As a result of various experimental analyzes to solve the above problems, the present inventors have found that the reinforcing property of carbon black can be further improved by using a specific vulcanization accelerator in a specific kneading method. The present invention has been completed.
That is, the present invention
[1] At least one compound (C) selected from a rubber component (A) selected from natural rubber and synthetic diene rubber, a filler containing carbon black (B), and a vulcanization accelerator. The rubber composition is kneaded in a plurality of stages, and the rubber component (A) and the carbon black (B) are mixed in a first stage (X) of kneading. A method for producing a rubber composition, wherein all or part of the rubber composition is kneaded, and at least one compound (C) selected from the vulcanization accelerator is added and kneaded in a stage before the final stage of kneading,
[2] At least one compound (C) selected from the rubber component (A), all or part of the carbon black (B), and the vulcanization accelerator in the first stage (X) of the kneading. In addition to kneading, the method for producing a rubber composition according to [1],
[3] After kneading all or part of the rubber component (A) and the carbon black (B) in the first stage (X) of the kneading, the vulcanization is performed in the middle of the first stage (X). The method for producing a rubber composition according to [2] above, wherein at least one compound (C) selected from accelerators is added and further kneaded, and [4] the rubber composition is divided into three or more stages. Kneading in the first kneading step, kneading all or part of the rubber component (A) and the carbon black (B) in the first kneading step (X), and after the second kneading step and from the final step. The method for producing a rubber composition according to the above [1], wherein at least one compound (C) selected from the vulcanization accelerator is added and kneaded in the previous step (Y). It is.

According to the present invention, it is possible to provide a method for producing a rubber composition that can improve low heat buildup.

The present invention is described in detail below.
The method for producing the rubber composition of the present invention is selected from at least one rubber component (A) selected from natural rubber and synthetic diene rubber, a filler containing carbon black (B), and a vulcanization accelerator. A method for producing a rubber composition comprising at least one compound (C), wherein the rubber composition is kneaded in a plurality of stages, and in the first stage (X) of kneading, the rubber component (A), And all or a part of the carbon black (B) is kneaded, and at least one compound (C) selected from the vulcanization accelerator is added and kneaded before the final stage of kneading. To do.
In the present invention, at least one compound (C) selected from vulcanization accelerators is added and kneaded before the final stage of kneading because the reinforcing property of the carbon black is improved, and the rubber composition This is to further increase the low heat generation property (reducing hysteresis loss).

The manufacturing method of the rubber composition of the present invention includes first, second and third manufacturing methods, which will be sequentially described below.
The first production method according to the present invention is selected from at least one rubber component (A) selected from natural rubber and synthetic diene rubber, a filler containing carbon black (B), and a vulcanization accelerator. A method for producing a rubber composition comprising at least one compound (C), wherein the rubber composition is kneaded in a plurality of stages, and in the first stage (X) of kneading, the rubber component (A), All or part of the carbon black (B) and at least one compound (C) selected from the vulcanization accelerator are added and kneaded.
In the first production method according to the present invention, at least one compound (C) selected from the vulcanization accelerator in the first stage (X) of kneading {hereinafter referred to as at least one compound selected from vulcanization accelerators Compound (C) may be abbreviated as “compound (C)”. } To knead | mix, without increasing a kneading | mixing process, the reinforcement property of carbon black can be improved and the low exothermic property of a rubber composition can be made higher (hysteresis loss can be reduced).

The second production method according to the present invention is selected from at least one rubber component (A) selected from natural rubber and synthetic diene rubber, a filler containing carbon black (B), and a vulcanization accelerator. A method for producing a rubber composition comprising at least one compound (C), wherein the rubber composition is kneaded in a plurality of stages, and in the first stage (X) of kneading, the rubber component (A) In addition, after all or part of the carbon black (B) is kneaded, the compound (C) is added and further kneaded in the middle of the first stage (X).
In the second production method according to the present invention, after kneading all or part of the rubber component (A) and carbon black (B) in the first stage (X) of kneading, the middle of the first stage (X) The compound (C) is added and kneaded further in order that the carbon black (B) is dispersed in the rubber component (A), and then the surface functional groups of the carbon black (B) react with the compound (C). This is because the reinforcing property of carbon black can be further enhanced. Thereby, the low heat generation property of the rubber composition according to the second production method can be further increased (hysteresis loss can be reduced).
From this point of view, when the rubber composition is kneaded in three or more kneading steps and the compound (C) is added in the first kneading step (X), the rubber composition is added in the second kneading step. The addition of a part of carbon black to (the carbon black is dividedly added to the first stage (X) and the second stage of kneading) is from the first stage (X) of the kneading where the compound (C) is added. Carbon black will be added at a later stage of kneading, and the effect of the present invention of further enhancing the reinforcing property of the carbon black and further improving the low heat buildup of the rubber composition will be reduced. Therefore, when adding the compound (C) in the first stage (X) of kneading, it is not preferable to add most of the carbon black to the second stage of kneading.

The third production method according to the present invention is selected from at least one rubber component (A) selected from natural rubber and synthetic diene rubber, a filler containing carbon black (B), and a vulcanization accelerator. A method for producing a rubber composition comprising at least one compound (C), wherein the rubber composition is kneaded in three or more kneading stages, and the rubber component is kneaded in the first stage (X) of kneading. All or part of (A) and carbon black (B) is kneaded, and the compound (C) is added and kneaded in the stage (Y) after the second stage and before the final stage of the kneading. To do.
In the third production method according to the present invention, after kneading all or part of the rubber component (A) and the carbon black (B) in the first stage of kneading, and after the second stage of kneading and The compound (C) is added and kneaded in the stage (Y) before the final stage because the carbon black (B) is sufficiently dispersed in the rubber component (A), and then the surface functionality of the carbon black (B). This is because the group and the compound (C) can react and the reinforcing property of the carbon black can be further enhanced. Thereby, the low exothermic property of the rubber composition according to the third production method can be further increased (hysteresis loss can be reduced).
In addition, in the second stage of kneading, adding a part of carbon black to the rubber composition (carbon black is dividedly added to the first stage and the second stage of kneading) is the dispersion of carbon black (B). From the viewpoint of enhancing the properties, it is preferable. However, adding most of the carbon black to the second stage of kneading may not improve the dispersibility of the carbon black (B).

In the present invention, the maximum temperature of the rubber composition in the first stage (X) of kneading is from 150 to 190 ° C. in order to enhance the reinforcing property of the carbon black and improve the low heat build-up of the rubber composition. It is preferably 150 to 180 ° C, more preferably 160 to 180 ° C, and further preferably 165 to 175 ° C.
Further, the kneading time in the first stage (X) of kneading is preferably 3 to 15 minutes, more preferably 3 to 12 minutes, and further preferably 5 to 9 minutes. If the kneading time is 3 minutes or longer, the reinforcing property of the carbon black can be improved, and if the kneading time is 15 minutes or shorter, the rubber component (A) will not be excessively reduced in molecular weight. is there.

In the first stage (X) of kneading in the second production method according to the present invention, the temperature of the rubber composition when adding the compound (C) is preferably 130 ° C. or higher, and preferably 130 to 180 ° C. More preferably, the temperature is 140 to 180 ° C, still more preferably 140 to 170 ° C. If the temperature of the rubber composition when adding the compound (C) is 130 ° C. or higher, the carbon black (B) is dispersed in the rubber component (A) and then the surface functional groups of the carbon black (B) This is because the compound (C) can react.
Time until the compound (C) is added during the first stage (X) after all or part of the rubber component (A) and the carbon black (B) are kneaded in the first stage (X) of the kneading. Is preferably 10 to 300 seconds, more preferably 10 to 180 seconds, still more preferably 30 to 180 seconds, still more preferably 30 to 150 seconds, and more preferably 30 to 120 seconds. It is particularly preferable to do this. If this time is 10 seconds or more, the dispersibility of the carbon black (B) in the rubber component (A) can be improved. Even if this time exceeds 300 seconds, since the dispersion of the carbon black (B) in the rubber component (A) is sufficiently advanced, it is difficult to enjoy further effects, and the upper limit is preferably set to 300 seconds. From this viewpoint, the upper limit value is more preferably set to 180 seconds.

In the third production method according to the present invention, in order to increase the reinforcing property of the carbon black and to improve the low heat build-up of the rubber composition, the second and subsequent stages of the kneading according to the present invention are performed from the final stage. The maximum temperature of the rubber composition in the previous stage (Y) is preferably 140 to 190 ° C., more preferably 150 to 190 ° C., further preferably 160 to 180 ° C., and 165 to A temperature of 175 ° C. is particularly preferable.
From the above viewpoint, the maximum temperature of the rubber composition in the first stage of kneading in the third production method according to the present invention is preferably 150 to 190 ° C., more preferably 150 to 180 ° C. Preferably, the temperature is 150 to 170 ° C.

In the third production method according to the present invention, the kneading time in the stage (Y) after the second stage of the kneading and before the final stage is preferably 2 to 15 minutes, more preferably 3 to 15 minutes. It is preferably 3 to 12 minutes, more preferably 3 to 9 minutes. If the kneading time is 2 minutes or longer, the reinforcing property of the carbon black can be improved, and if the kneading time is 15 minutes or shorter, the rubber component (A) will not be excessively lowered in molecular weight. is there.
From the above viewpoint, the kneading time in the first stage of kneading in the third production method according to the present invention is preferably 3 to 15 minutes, more preferably 3 to 10 minutes. 8 minutes is more preferable, and 3 to 6 minutes is particularly preferable.

The rubber composition kneading step in the present invention includes at least two stages of a first stage (X) of kneading not containing other vulcanization accelerators excluding the compound (C) and a final stage of kneading in which the vulcanizing agent is blended. It includes a stage, and if necessary, may include an intermediate stage (Y) of kneading that does not contain other vulcanizing agents other than the compound (C).
The first stage (X) of kneading in the present invention refers to the first stage of kneading the rubber component (A) and carbon black (B). In the first stage, the rubber component (A) and carbon black ( The step of kneading with a filler other than B) or the case of preliminarily kneading only the rubber component (A) is not included.

The kneading step of the rubber composition in the third production method according to the present invention includes a first stage of kneading in which a filler containing the rubber component (A) and carbon black (B) is blended and the compound (C) is not blended. Mixing the compound (C) and mixing the vulcanizing agent with the step (Y) after the second stage of the kneading and not including the other vulcanization accelerators excluding the compound (C) and before the final stage. In addition to the stage (Y), other intermediate stages of kneading that do not contain a vulcanizing agent may be included as necessary. The kneading step of the rubber composition in the third production method according to the present invention preferably includes 3 to 8 steps, more preferably 3 to 6 steps, and further preferably 3 to 5 steps. When there are too many kneading | mixing steps, productivity of a rubber composition will fall.

[Rubber component (A)]
The rubber component (A) used in the method for producing a rubber composition of the present invention comprises at least one selected from natural rubber and synthetic diene rubber. Here, as the synthetic diene rubber, styrene-butadiene copolymer rubber (SBR), polybutadiene rubber (BR), polyisoprene rubber (IR), butyl rubber (IIR), halogenated butyl rubber (Cl-IIR, Br-IIR). Etc.), ethylene-propylene-diene terpolymer rubber (EPDM), ethylene-butadiene copolymer rubber (EBR), propylene-butadiene copolymer rubber (PBR), and the like. Natural rubber and synthetic diene rubber may be used singly or as a blend of two or more.

[Filler]
The filler used in the method for producing a rubber composition of the present invention contains carbon black (B). The filler of the rubber composition according to the present invention may be carbon black (B) alone, but in addition to carbon black (B), an inorganic filler such as silica or aluminum hydroxide may be used as the subject of the present invention. It can be used as long as it does not violate the solution.
From the viewpoint of improving the reinforcement of carbon black and improving the low heat build-up, the rubber composition according to the present invention preferably contains 70 to 100% by mass of carbon black (B) in the total amount of the filler.
The filler according to the present invention is preferably used in an amount of 20 to 180 parts by mass with respect to 100 parts by mass of the rubber component (A).

[Carbon black (B)]
Carbon black (B) used in the method for producing a rubber composition according to the present invention is not particularly limited. For example, high, medium or low structure SAF, N234, ISAF, IISAF, N339, HAF, FEF, GPF, It is preferable to use SRF grade carbon black, particularly SAF, N234, ISAF, IISAF, N339, HAF, and FEF grade carbon black. The nitrogen adsorption specific surface area (N ₂ SA, measured according to JIS K 6217-2: 2001) is preferably 30 to 250 m ² / g. This carbon black may be used individually by 1 type, and may be used in combination of 2 or more type.
The carbon black (B) according to the present invention is preferably used in an amount of 20 to 150 parts by mass with respect to 100 parts by mass of the rubber component (A). If it is 20 parts by mass or more, it is preferable from the viewpoint of securing rubber reinforcement, and if it is 150 parts by mass or less, it is preferable from the viewpoint of improving low heat generation (reducing hysteresis loss). Furthermore, it is more preferable to use 30 to 120 parts by mass, and it is more preferable to use 30 to 110 parts by mass.

[Compound (C)]
The compound (C) used in the method for producing a rubber composition of the present invention is at least one compound selected from vulcanization accelerators, and sulfenamides, thiazoles, thiurams, dithiocarbamates, thioureas And at least one compound selected from xanthogenic acids.

Examples of the sulfenamides used in the method for producing the rubber composition of the present invention include N-cyclohexyl-2-benzothiazolylsulfenamide, N, N-dicyclohexyl-2-benzothiazolylsulfenamide, N-tert -Butyl-2-benzothiazolylsulfenamide, N-oxydiethylene-2-benzothiazolylsulfenamide, N-methyl-2-benzothiazolylsulfenamide, N-ethyl-2-benzothiazolylsulfen Amide, N-propyl-2-benzothiazolylsulfenamide, N-butyl-2-benzothiazolylsulfenamide, N-pentyl-2-benzothiazolylsulfenamide, N-hexyl-2-benzothiazoli Rusulfenamide, N-pentyl-2-benzothiazolylsulfenamide, -Octyl-2-benzothiazolylsulfenamide, N-2-ethylhexyl-2-benzothiazolylsulfenamide, N-decyl-2-benzothiazolylsulfenamide, N-dodecyl-2-benzothiazolylsulfenamide Phenamide, N-stearyl-2-benzothiazolylsulfenamide, N, N-dimethyl-2-benzothiazolylsulfenamide, N, N-diethyl-2-benzothiazolylsulfenamide, N, N- Dipropyl-2-benzothiazolylsulfenamide, N, N-dibutyl-2-benzothiazolylsulfenamide, N, N-dipentyl-2-benzothiazolylsulfenamide, N, N-dihexyl-2-benzo Thiazolylsulfenamide, N, N-dipentyl-2-benzothiazolylsulfenami N, N-dioctyl-2-benzothiazolylsulfenamide, N, N-di-2-ethylhexylbenzothiazolylsulfenamide, N-decyl-2-benzothiazolylsulfenamide, N, N-didodecyl -2-benzothiazolylsulfenamide, N, N-distearyl-2-benzothiazolylsulfenamide and the like. Of these, N-cyclohexyl-2-benzothiazolylsulfenamide and N-tert-butyl-2-benzothiazolylsulfenamide are preferable because of their high reactivity with the surface functional groups of carbon black.

Examples of thiazoles used in the method for producing a rubber composition of the present invention include 2-mercaptobenzothiazole, di-2-benzothiazolyl disulfide, zinc salt of 2-mercaptobenzothiazole, and cyclohexylamine of 2-mercaptobenzothiazole. Salt, 2- (N, N-diethylthiocarbamoylthio) benzothiazole, 2- (4′-morpholinodithio) benzothiazole, 4-methyl-2-mercaptobenzothiazole, di- (4-methyl-2-benzothiazolyl) Disulfide, 5-chloro-2-mercaptobenzothiazole, 2-mercaptobenzothiazole sodium, 2-mercapto-6-nitrobenzothiazole, 2-mercapto-naphtho [1,2-d] thiazole, 2-mercapto-5-methoxy Benzothiazole, 6-a And mino-2-mercaptobenzothiazole. Of these, 2-mercaptobenzothiazole, bis (4-methylbenzothiazolyl-2) -disulfide, and di-2-benzothiazolyl disulfide are highly reactive with the surface functional groups of carbon black. preferable.

The thiurams used in the method for producing the rubber composition of the present invention include tetramethylthiuram disulfide, tetraethylthiuram disulfide, tetrapropylthiuram disulfide, tetraisopropylthiuram disulfide, tetrabutylthiuram disulfide, tetrapentylthiuram disulfide, tetrahexylthiuram disulfide , Tetraheptyl thiuram disulfide, tetraoctyl thiuram disulfide, tetranonyl thiuram disulfide, tetradecyl thiuram disulfide, tetradodecyl thiuram disulfide, tetrastearyl thiuram disulfide, tetrabenzyl thiuram disulfide, tetrakis (2-ethylhexyl) thiuram disulfide, tetramethyl thiuram monosulfide , Tetraethylthi Ram monosulfide, tetrapropyl thiuram monosulfide, tetraisopropyl thiuram monosulfide, tetrabutyl thiuram monosulfide, tetrapentyl thiuram monosulfide, tetrahexyl thiuram monosulfide, tetraheptyl thiuram monosulfide, tetraoctyl thiuram monosulfide, tetranonyl thiuram monosulfide Examples thereof include sulfide, tetradecyl thiuram monosulfide, tetradodecyl thiuram monosulfide, tetrastearyl thiuram monosulfide, tetrabenzyl thiuram monosulfide, dipentamethylene thiuram tetrasulfide and the like. Of these, tetrakis (2-ethylhexyl) thiuram disulfide and tetrabenzylthiuram disulfide are preferred because of their high reactivity with the surface functional groups of carbon black.

Examples of thioureas used in the method for producing a rubber composition of the present invention include thiourea, N, N′-diphenylthiourea, trimethylthiourea, N, N′-diethylthiourea, N, N′-dimethylthiourea, N , N′-dibutylthiourea, ethylenethiourea, N, N′-diisopropylthiourea, N, N′-dicyclohexylthiourea, 1,3-di (o-tolyl) thiourea, 1,3-di (p-tolyl) ) Thiourea, 1,1-diphenyl-2-thiourea, 2,5-dithiobiurea, guanylthiourea, 1- (1-naphthyl) -2-thiourea, 1-phenyl-2-thiourea, p-tolylthio Examples include urea and o-tolylthiourea. Of these, thiourea, N, N′-diethylthiourea, trimethylthiourea, N, N′-diphenylthiourea and N, N′-dimethylthiourea are highly reactive with the surface functional groups of carbon black. preferable.

Examples of the dithiocarbamate used in the method for producing the rubber composition of the present invention include zinc dimethyldithiocarbamate, zinc diethyldithiocarbamate, zinc dipropyldithiocarbamate, zinc diisopropyldithiocarbamate, zinc dibutyldithiocarbamate, zinc dipentyldithiocarbamate, and dihexyl. Zinc dithiocarbamate, zinc diheptyldithiocarbamate, zinc dioctyldithiocarbamate, zinc di (2-ethylhexyl) dithiocarbamate, zinc didecyldithiocarbamate, zinc didodecyldithiocarbamate, zinc N-pentamethylenedithiocarbamate, N-ethyl-N -Zinc phenyldithiocarbamate, zinc dibenzyldithiocarbamate, copper dimethyldithiocarbamate, diethyldithiocarbamate Copper oxide, copper dipropyldithiocarbamate, copper diisopropyldithiocarbamate, copper dibutyldithiocarbamate, copper dipentyldithiocarbamate, copper dihexyldithiocarbamate, copper diheptyldithiocarbamate, copper dioctyldithiocarbamate, copper di (2-ethylhexyl) dithiocarbamate , Copper didecyl dithiocarbamate, copper didodecyl dithiocarbamate, copper N-pentamethylenedithiocarbamate, copper dibenzyldithiocarbamate, sodium dimethyldithiocarbamate, sodium diethyldithiocarbamate, sodium dipropyldithiocarbamate, sodium diisopropyldithiocarbamate, dibutyldithiocarbamine Acid sodium, sodium dipentyldithiocarbamate, dihexyldithio Sodium carbamate, sodium diheptyldithiocarbamate, sodium dioctyldithiocarbamate, sodium di (2-ethylhexyl) dithiocarbamate, sodium didecyldithiocarbamate, sodium didodecyldithiocarbamate, sodium N-pentamethylenedithiocarbamate, sodium dibenzyldithiocarbamate , Ferric dimethyldithiocarbamate, ferric diethyldithiocarbamate, ferric dipropyldithiocarbamate, ferric diisopropyldithiocarbamate, ferric dibutyldithiocarbamate, ferric dipentyldithiocarbamate, ferric dihexyldithiocarbamate , Ferric diheptyldithiocarbamate, ferric dioctyldithiocarbamate, di (2-ethylhexyl) ) Ferric dithiocarbamate, ferric didecyl dithiocarbamate, ferric didodecyl dithiocarbamate, N- ferric pentamethylene dithiocarbamate, ferric dibenzyl dithiocarbamate and the like. Of these, zinc dibenzyldithiocarbamate, zinc N-ethyl-N-phenyldithiocarbamate, zinc dimethyldithiocarbamate and copper dimethyldithiocarbamate are preferred because of their high reactivity with the surface functional groups of carbon black.

The xanthates used in the method for producing the rubber composition of the present invention include zinc methylxanthate, zinc ethylxanthate, zinc propylxanthate, zinc isopropylxanthate, zinc butylxanthate, zinc pentylxanthate, and hexylxanthogen. Zinc oxide, zinc heptylxanthate, zinc octylxanthate, zinc 2-ethylhexylxanthate, zinc decylxanthate, zinc dodecylxanthate, potassium methylxanthate, potassium ethylxanthate, potassium propylxanthate, potassium isopropylxanthate, Potassium butylxanthate, potassium pentylxanthate, potassium hexylxanthate, potassium heptylxanthate, Potassium octylxanthate, potassium 2-ethylhexylxanthate, potassium decylxanthate, potassium dodecylxanthate, sodium methylxanthate, sodium ethylxanthate, sodium propylxanthate, sodium butylxanthate, pentylxanthate Examples thereof include sodium, sodium hexyl xanthate, sodium heptyl xanthate, sodium octyl xanthate, sodium 2-ethylhexyl xanthate, sodium decyl xanthate, sodium dodecyl xanthate, and the like. Of these, zinc isopropylxanthate is preferred because of its high reactivity with the surface functional groups of carbon black.

The compound (C) in the rubber composition in the first stage (X) of kneading according to the method for producing a rubber composition of the present invention is 0.1 to 8.0 with respect to 100 parts by mass of the rubber component (A). Preferably, 0.3 parts by weight is added, more preferably 0.3 to 6.0 parts by weight is added, still more preferably 0.4 to 3.0 parts by weight is added, and 0.5 to 3.0 parts by weight is added. It is particularly preferred that If it is 0.1 parts by mass or more, the reinforcing property of carbon black can be improved, and if it is 0.3 parts by mass or more, the reinforcing property of carbon black can be further improved, and 8.0 parts by mass. If it is below, excessive use can be avoided, and if it is 6.0 parts by mass or less, excessive use can be further avoided, which is advantageous in terms of cost and economical.
Since the vulcanization accelerator (C) is also used as a sulfur vulcanization accelerator, an appropriate amount may be blended as desired even in the final stage of kneading.

In the method for producing a rubber composition of the present invention, various compounding agents such as zinc oxide, fatty acid, resin acid and other vulcanization activators, anti-aging agents and the like which are usually compounded in the rubber composition are kneaded as necessary. The kneading is carried out in the first stage (X) or the final stage, or in the intermediate stage between the first stage (X) and the final stage.
As a kneading apparatus in the production method of the present invention, a Banbury mixer, a roll, an intensive mixer, a twin screw extruder, or the like is used.

According to the first production method, the second production method and the third production method of the present invention, a rubber component (A) composed of at least one selected from natural rubber and synthetic diene rubber, and carbon black (B) Since the rubber composition containing at least one compound (C) selected from the filler and the vulcanization accelerator can suitably improve the low heat buildup, it is suitable for various pneumatic tires and various industrial rubber products. Used.

Hereinafter, the present invention will be described in more detail with reference to examples. However, the present invention is not limited to the following examples.
The low exothermic property (tan δ index) was evaluated by the following method.

Low exothermicity (tan δ index)
Using a viscoelasticity measuring device (Rheometrics), tan δ was measured at a temperature of 60 ° C., a dynamic strain of 5%, and a frequency of 15 Hz. Comparative Examples a1, a4, a8, a10, b1, b4, b8, b10, c1, c4, c7, c9 or c14 were represented by the following formula with the reciprocal of tan δ being 100. A larger index value indicates a lower exothermic property and a smaller hysteresis loss.
Low exothermic index = {(tan δ of vulcanized rubber composition of Comparative Examples a1, a4, a8, a10, b1, b4, b8, b10, c1, c4, c7, c9 or c14) / (test vulcanized rubber) Composition tan δ)} × 100

Examples a1 to a90 and comparative examples a1 to a3
93 kinds of rubber compositions prepared by adjusting the compounding formulations shown in Tables a1 to a8, the kneading time in the first stage (X) of kneading and the maximum temperature of the rubber composition and kneading with a Banbury mixer Was prepared. In the first stage (X) of kneading the rubber compositions of Examples a1 to a90, all of the rubber component (A), carbon black (B), compound (C), and other compounding agents were added and kneaded. In the first stage (X) of the kneading of the rubber compositions of Comparative Examples a1 to a3, the rubber component (A), all of the carbon black (B), and other compounding agents were added, but the compound (C) was Kneaded without adding.
The low exothermic properties (tan δ index) of the 93 types of rubber compositions obtained were evaluated by the above methods. The results are shown in Tables a1 to a8.

[note]
* A1: Emulsion polymerization SBR manufactured by JSR Corporation, trade name “# 1500”
* A2: Asahi Carbon Co., Ltd., trade name “# 80”
* A3: N- (1,3-dimethylbutyl) -N′-phenyl-p-phenylenediamine, manufactured by Ouchi Shinsei Chemical Co., Ltd., trade name “NOCRACK 6C”
* A4: N-cyclohexyl-2-benzothiazolylsulfenamide, manufactured by Ouchi Shinsei Chemical Industry Co., Ltd., trade name “Noxeller CZ-G”
* A5: Vulcanization accelerator MBTS: Di-2-benzothiazolyl disulfide, manufactured by Sanshin Chemical Industry Co., Ltd., trade name “Sunceller DM”
* A6: Tetrakis (2-ethylhexyl) thiuram disulfide, manufactured by Ouchi Shinsei Chemical Co., Ltd., trade name “Noxeller TOT-N”
* A7: N, N′-diethylthiourea, manufactured by Ouchi Shinsei Chemical Industry Co., Ltd., trade name “Noxeller EUR”
* A8: Zinc dibenzyldithiocarbamate, manufactured by Ouchi Shinsei Chemical Co., Ltd., trade name “Noxeller ZTC”
* A9: 2,2,4-trimethyl-1,2-dihydroquinoline polymer, manufactured by Ouchi Shinsei Chemical Co., Ltd., trade name “NOCRACK 224”
* A10: Vulcanization accelerator TBBS: N-tert-butyl-2-benzothiazolylsulfenamide, manufactured by Sanshin Chemical Industry Co., Ltd., trade name “Sunseller NS”

[note]
* A1 to * a10 are the same as those in Table a1.

[note]
* A1 to * a10 are the same as those in Table a1.

[note]
* A1 to * a10 are the same as those in Table a1.
* A12: 2-mercaptobenzothiazole, manufactured by Ouchi Shinsei Chemical Co., Ltd., trade name “Noxeller MP”
* A13: Bis (4-methylbenzothiazolyl-2) -disulfide, manufactured by Sanshin Chemical Industry Co., Ltd., trade name “Sunseller 4MDM”
* A14: Zinc salt of 2-mercaptobenzothiazole, manufactured by Ouchi Shinsei Chemical Co., Ltd., trade name “Noxeller MZ”

[note]
* A1 to * a10 are the same as those in Table a1.
* A15: Tetrakis (benzyl) thiuram disulfide, manufactured by Sanshin Chemical Industry Co., Ltd., trade name “Sunseller TBZTD”

[note]
* A1 to * a10 are the same as those in Table a1.
* A16: Trimethylthiourea, manufactured by Sanshin Chemical Industry Co., Ltd., trade name “Sunseller TMU”
* A17: N, N'-diphenylthiourea, manufactured by Ouchi Shinsei Chemical Industry Co., Ltd., trade name "Noxeller C"

[note]
* A1 to * a10 are the same as those in Table a1.
* A18: Zinc N-ethyl-N-phenyldithiocarbamate, manufactured by Sanshin Chemical Industry Co., Ltd., trade name “Suncellor PX”
* A19: Zinc dimethyldithiocarbamate, manufactured by Sanshin Chemical Industry Co., Ltd., trade name “Sunceller PZ”
* A20: Copper dimethyldithiocarbamate, manufactured by Sanshin Chemical Industry Co., Ltd., trade name “Sunseller TT-CU”

[note]
* A1 to * a10 are the same as those in Table a1.
* A21: Zinc isopropylxanthate, manufactured by Ouchi Shinsei Chemical Co., Ltd., trade name “Noxeller ZIX-O”

Examples a91 to a96 and Comparative examples a4 to a7
Next, the blending formulation shown in Table a9, the kneading time in the first stage (X) of kneading and the maximum temperature of the rubber composition are adjusted and kneaded with a Banbury mixer, and 10 kinds of rubber compositions are prepared. Prepared. In the first stage (X) of the kneading of the rubber compositions of Examples a91 to a96, the rubber component (A), all or part of the carbon black (B), the compound (C), and other compounding agents are added. Kneaded. In the first step (X) of kneading the rubber compositions of Comparative Examples a4 to a7, the rubber component (A), all or part of the carbon black (B), and other compounding agents were added. K) was added without adding.
In addition, the rubber compositions of Examples a92, a94 and a96 and Comparative Examples a5 and a7 added the remainder of carbon black (B) in the second stage of kneading. The maximum temperature of the rubber composition in the second stage of kneading was 170 ° C. for all.
The low exothermic properties (tan δ index) of the 10 types of rubber compositions obtained were evaluated by the above methods. The results are shown in Table a9.

[note]
* A1 to * a15 are the same as Tables a1 to a5.
* A22: manufactured by JSR Corporation, emulsion polymerization SBR, trade name “# 1712” (37.5 parts by mass of oil-extended oil with respect to 100 parts by mass of SBR)

Examples a97 to a99 and comparative examples a8 and a9
The blending formulation shown in Table a10, the kneading time in the first stage (X) of kneading and the maximum temperature of the rubber composition were adjusted and kneaded with a Banbury mixer to prepare five types of rubber compositions. In the first stage (X) of kneading the rubber compositions of Examples a97 to a99, the rubber component (A), all of the carbon black (B) and the compound (C), and other compounding agents were added and kneaded. In the first stage (X) of kneading the rubber compositions of Comparative Examples a8 and a9, all of the rubber component (A) and carbon black (B) and other compounding agents were added, but the compound (C) was Kneaded without adding.
The low exothermic properties (tan δ index) of the five types of rubber compositions obtained were evaluated by the above methods. The results are shown in Table a10.

[note]
* A1 to * a15 are the same as Tables a1 to a5.
* A23: RSS # 3
* A24: Polybutadiene rubber manufactured by JSR Corporation, trade name “BR01”
* A25: Carbon black manufactured by Asahi Carbon Co., Ltd., trade name “# 65”

Examples a100 to a107 and comparative examples a10 to a13
Twelve kinds of rubber compositions were prepared by adjusting the compounding formulation shown in Table a11, the kneading time in the first stage (X) of kneading, and adjusting the rubber composition to the maximum temperature and kneading with a Banbury mixer. In the first stage (X) of kneading the rubber compositions of Examples a100 to a107, the rubber component (A), carbon black (B), compound (C), and other compounding agents were added and kneaded. In the first stage (X) of kneading the rubber compositions of Comparative Examples a10 to a13, the rubber component (A), carbon black (B), and other compounding agents were added, but the compound (C) was not added. And kneaded.
The low exothermic properties (tan δ index) of the 12 types of rubber compositions obtained were evaluated by the above methods. The results are shown in Table a11.

[note]
* A1 to * a22 are the same as Tables a1 to a9.
* A26: Process oil manufactured by Sankyo Oil Chemical Co., Ltd., trade name “A / O mix”
* A27: Made by Tosoh Silica Co., Ltd., trade name “Nip Seal AQ”, BET specific surface area 205 m ² / g
* A28: Bis (3-triethoxysilylpropyl) disulfide (average sulfur chain length: 2.35), silane coupling agent manufactured by Evonik, trade name “Si75” (registered trademark)
* A29: 1,3-diphenylguanidine, manufactured by Sanshin Chemical Industry Co., Ltd., trade name “Sunseller D”

Examples b1 to b89 and comparative examples b1 to b3
Compound (C) shown in Table b1 to Table b9, compounding formula, kneading time in first stage (X) of kneading, maximum temperature of rubber composition, and first stage (X) of kneading The rubber composition was adjusted to the temperature (° C.) of the rubber composition when added and kneaded with a Banbury mixer to prepare 92 types of rubber compositions of Examples b1 to b89 and Comparative examples b1 to b3.
In the first stage (X) of kneading the rubber compositions of Examples b1 to b89, all of the rubber component (A), carbon black (B), and other compounding agents were kneaded, and then the first stage (X ), The compound (C) was added and further kneaded when the rubber composition reached the temperature shown in Tables b1 to b9.
In the first stage (X) of the kneading of the rubber compositions of Comparative Examples b1 to b3, all of the rubber component (A), carbon black (B), and other compounding agents were added, but the compound (C) was Kneaded without adding.
The low exothermic properties (tan δ index) of the 92 types of rubber compositions obtained were evaluated by the above methods. The results are shown in Tables b1 to b9.

[note]
* B1: JSR Corporation, emulsion polymerization SBR, trade name "# 1500"
* B2: Carbon black manufactured by Asahi Carbon Co., Ltd., trade name “# 80”
* B3: N- (1,3-dimethylbutyl) -N′-phenyl-p-phenylenediamine, manufactured by Ouchi Shinsei Chemical Co., Ltd., trade name “NOCRACK 6C”
* B4: Vulcanization accelerator TBBS: N-tert-butyl-2-benzothiazolylsulfenamide, manufactured by Sanshin Chemical Industry Co., Ltd., trade name “Sunseller NS”
* B5: 2-mercaptobenzothiazole, manufactured by Ouchi Shinsei Chemical Co., Ltd., trade name “Noxeller MP”
* B6: Tetrakis (2-ethylhexyl) thiuram disulfide, manufactured by Ouchi Shinsei Chemical Co., Ltd., trade name “Noxeller TOT-N”
* B7: N, N'-diethylthiourea, manufactured by Ouchi Shinsei Chemical Industry Co., Ltd., trade name "Noxeller EUR"
* B8: Zinc dibenzyldithiocarbamate, manufactured by Ouchi Shinsei Chemical Co., Ltd., trade name “Noxeller ZTC”
* B9: 2,2,4-trimethyl-1,2-dihydroquinoline polymer, manufactured by Ouchi Shinsei Chemical Co., Ltd., trade name “NOCRACK 224”
* B10: Vulcanization accelerator MBTS: Di-2-benzothiazolyl disulfide, manufactured by Sanshin Chemical Industry Co., Ltd., trade name “Sunceller DM”

[note]
* B1 to * b10 are the same as those in Table b1.

[note]
* B1 to * b10 are the same as those in Table b1.

[note]
* B1 to * b10 are the same as those in Table b1.
* B11: N-cyclohexyl-2-benzothiazolylsulfenamide, manufactured by Ouchi Shinsei Chemical Industry Co., Ltd., trade name “Noxeller CZ-G”

[note]
* B1 to * b10 are the same as those in Table b1.
* B12: Zinc salt of 2-mercaptobenzothiazole, manufactured by Ouchi Shinsei Chemical Co., Ltd., trade name “Noxeller MZ”
* B13: Bis (4-methylbenzothiazolyl-2) -disulfide, manufactured by Sanshin Chemical Industry Co., Ltd., trade name “Sunseller 4MDM”

[note]
* B1 to * b10 are the same as those in Table b1.
* B14: Tetrakis (benzyl) thiuram disulfide, manufactured by Sanshin Chemical Industry Co., Ltd., trade name “Sunseller TBZTD”

[note]
* B1 to * b10 are the same as those in Table b1.
* B15: Trimethylthiourea, manufactured by Sanshin Chemical Industry Co., Ltd., trade name “Sunseller TMU”
* B16: N, N′-diphenylthiourea, manufactured by Ouchi Shinsei Chemical Industry Co., Ltd., trade name “Noxeller C”

[note]
* B1 to * b10 are the same as those in Table b1.
* B17: Zinc N-ethyl-N-phenyldithiocarbamate, manufactured by Sanshin Chemical Industry Co., Ltd., trade name “Sunseller PX”
* B18: Zinc dimethyldithiocarbamate, manufactured by Sanshin Chemical Industry Co., Ltd., trade name "Sunseller PZ"
* B19: Copper dimethyldithiocarbamate, manufactured by Sanshin Chemical Industry Co., Ltd., trade name “Sunseller TT-CU”

[note]
* B1 to * b10 are the same as those in Table b1.
* B20: Zinc isopropyl xanthate, manufactured by Ouchi Shinsei Chemical Co., Ltd., trade name “Noxeller ZIX-O”

Examples b90 to b95 and comparative examples b4 to b7
Next, the compound (C) is added in the middle of the compounding prescription and kneading time in the first stage (X) of kneading, the maximum temperature of the rubber composition, and the first stage (X) of kneading shown in Table b10. Ten kinds of rubber compositions of Examples b90 to b95 and Comparative Examples b4 to b7 were prepared by adjusting to the temperature (° C.) of the rubber composition and kneading with a Banbury mixer.
In the first stage (X) of kneading the rubber compositions of Examples b90 to b95, after kneading the rubber component (A), the compounding amount shown in Table b10 of carbon black (B), and other compounding agents, When the rubber composition reached 140 ° C. during the first stage (X), the compound (C) was added and further kneaded.
In the first stage (X) of the kneading of the rubber compositions of Comparative Examples b4 to b7, the blending amounts shown in Table b10 of the rubber component (A) and carbon black (B) and other compounding agents were added. The compound (C) was kneaded without being added.
Further, the rubber compositions of Examples b91, b93 and b95 and Comparative Examples b5 and b7 were obtained by adding the remainder of carbon black (B) in the second stage of kneading. The maximum temperature of the rubber composition in the second stage of kneading was 170 ° C. for all.
The low exothermic properties (tan δ index) of the 10 types of rubber compositions obtained were evaluated by the above methods. The results are shown in Table b10.

[note]
* B1 to * b14 are the same as Tables b1 to b6.
* B21: manufactured by JSR Corporation, emulsion polymerization SBR, trade name “# 1712” (37.5 parts by mass is oil-extended oil with respect to 100 parts by mass of SBR)

Examples b96 to b106 and comparative examples b8 to b13
Compound (C) shown in Table b11 and Table b12, compounding formula, kneading time in first stage (X) of kneading, maximum temperature of rubber composition, and first stage (X) of kneading The temperature was adjusted to the temperature (° C.) of the rubber composition when added and kneaded with a Banbury mixer to prepare 17 types of rubber compositions of Examples b96 to b106 and Comparative Examples b8 to b13.
In the first step (X) of kneading the rubber compositions of Examples b96 to b106, the rubber component (A), carbon black (B) alone, or all of carbon black (B) and silica, and other compounding agents are added. After kneading, compound (C) was added and further kneaded when the rubber composition reached 140 ° C. during the first stage (X).
In the first step (X) of kneading the rubber compositions of Comparative Examples b8 to b13, the rubber component (A), carbon black (B) alone, or all of carbon black (B) and silica, and other compounding agents Was added, but the compound (C) was not added and kneaded.
The low exothermic property (tan δ index) of the 17 kinds of rubber compositions obtained was evaluated by the above method. The results are shown in Tables b11 and b12.

[note]
* B1 to * b14 are the same as Tables b1 to b6.
* B22: Natural rubber RSS # 3
* B23: Polybutadiene rubber manufactured by JSR Corporation, trade name “BR01”
* B24: Carbon black manufactured by Asahi Carbon Co., Ltd., trade name “# 65”

[note]
* B1 to * b21 are the same as Tables b1 to b10.
* B25: Asahi Kasei Corporation, solution polymerization SBR, trade name “Toughden 3835” (37.5 parts by mass of oil-extended oil with respect to 100 parts by mass of SBR)
* B26: Process oil manufactured by Sankyo Oil Chemical Co., Ltd., trade name “A / O mix”
* B27: Silica manufactured by Tosoh Silica Co., Ltd., trade name “Nip Seal AQ”, BET specific surface area 205 m ² / g
* B28: Bis (3-triethoxysilylpropyl) disulfide (average sulfur chain length: 2.35), Evonik silane coupling agent, trade name “Si75” (registered trademark)
* B29: Vulcanization accelerator DPG: 1,3-diphenylguanidine, manufactured by Sanshin Chemical Industry Co., Ltd., trade name "Sunseller D"

Examples c1 to c97 and comparative examples c1 to c8
Examples c1 to c97 and Comparative Example c1 were prepared by blending the formulations shown in Tables c1 to c9, adjusting the kneading time in the second stage of kneading and the maximum temperature of the rubber composition, and kneading with a Banbury mixer. 105 types of rubber compositions of c8 to c8 were prepared.
In the first stage of kneading the rubber compositions of Examples c1 to c97 and Comparative Examples c1 to c8, all or a majority of the rubber component (A) and carbon black (B) and other compounding agents were added and kneaded for 3 minutes. When the maximum temperature of the rubber composition reached 160 ° C., the rubber composition was discharged from the Banbury mixer.
Next, in the second stage of kneading the rubber compositions of Examples c1 to c92, c94 and c96, the compound (C) was added and kneaded as shown in Tables c1 to c9. In the second step of kneading the rubber compositions of Examples c93, c95 and c97, the remainder of carbon black (B) and compound (C) were added and kneaded as shown in Table c9.
The rubber compositions of Comparative Examples c1, c4 and c7 did not provide the second stage of kneading. The rubber composition of Comparative Example c8 was kneaded as shown in Table c9 with the remainder of carbon black (B) added in the second stage, but no compound (C) was added in the second stage.
The low exothermic property (tan δ index) of the obtained 105 rubber compositions was evaluated by the above method. The results are shown in Tables c1 to c9.

[note]
* C1: Solution polymerization SBR-Ac: Solution polymerization SBR manufactured by Asahi Kasei Corporation, trade name “Toughden 2000”
* C2: Carbon black manufactured by Asahi Carbon Co., Ltd., trade name “# 80”
* C3: N- (1,3-dimethylbutyl) -N′-phenyl-p-phenylenediamine, manufactured by Ouchi Shinsei Chemical Co., Ltd., trade name “NOCRACK 6C”
* C4: Vulcanization accelerator TBBS: N-tert-butyl-2-benzothiazolylsulfenamide, manufactured by Sanshin Chemical Industry Co., Ltd., trade name “Sunseller NS”
* C5: Bis (4-methylbenzothiazolyl-2) -disulfide, manufactured by Sanshin Chemical Industry Co., Ltd., trade name “Sunseller 4MDM”
* C6: Tetrakis (benzyl) thiuram disulfide, manufactured by Sanshin Chemical Industry Co., Ltd., trade name “Sunseller TBZTD”
* C7: N, N′-diethylthiourea, manufactured by Ouchi Shinsei Chemical Industry Co., Ltd., trade name “Noxeller EUR”
* C8: Zinc dibenzyldithiocarbamate, manufactured by Ouchi Shinsei Chemical Co., Ltd., trade name “Noxeller ZTC”
* C9: 2,2,4-trimethyl-1,2-dihydroquinoline polymer, manufactured by Ouchi Shinsei Chemical Co., Ltd., trade name “NOCRACK 224”
* C10: Vulcanization accelerator MBTS: Di-2-benzothiazolyl disulfide, manufactured by Sanshin Chemical Industry Co., Ltd., trade name “Sunceller DM”

[note]
* C1 to * c10 are the same as those in Table c1.
* C11: Emulsion polymerization SBR-Bc: Emulsion polymerization SBR manufactured by JSR Corporation, trade name “# 1500”

[note]
* C1 to * c11 are the same as those in Tables c1 and c2.
* C12: N-cyclohexyl-2-benzothiazolylsulfenamide, manufactured by Ouchi Shinsei Chemical Industry Co., Ltd., trade name “Noxeller CZ-G”

[note]
* C1 to * c11 are the same as those in Tables c1 and c2.
* C13: 2-mercaptobenzothiazole, manufactured by Ouchi Shinsei Chemical Co., Ltd., trade name “Noxeller MP”
* C14: Zinc salt of 2-mercaptobenzothiazole, manufactured by Ouchi Shinsei Chemical Co., Ltd., trade name “Noxeller MZ”

[note]
* C1 to * c11 are the same as those in Tables c1 and c2.
* C15: Tetrakis (2-ethylhexyl) thiuram disulfide, manufactured by Ouchi Shinsei Chemical Co., Ltd., trade name “Noxeller TOT-N”

[note]
* C1 to * c11 are the same as those in Tables c1 and c2.
* C16: Trimethylthiourea, manufactured by Sanshin Chemical Industry Co., Ltd., trade name "Sunseller TMU"
* C17: N, N'-diphenylthiourea, manufactured by Ouchi Shinsei Chemical Industry Co., Ltd., trade name "Noxeller C"

[note]
* C1 to * c11 are the same as those in Tables c1 and c2.
* C18: Zinc N-ethyl-N-phenyldithiocarbamate, manufactured by Sanshin Chemical Industry Co., Ltd., trade name “Suncellor PX”
* C19: Zinc dimethyldithiocarbamate, manufactured by Sanshin Chemical Industry Co., Ltd., trade name “Sunceller PZ”
* C20: Copper dimethyldithiocarbamate, manufactured by Sanshin Chemical Industry Co., Ltd., trade name “Sunseller TT-CU”

[note]
* C1 to * c11 are the same as those in Tables c1 and c2.
* C21: Zinc isopropyl xanthate, manufactured by Ouchi Shinsei Chemical Co., Ltd., trade name “Noxeller ZIX-O”

[note]
* C1 to * c13 are the same as Tables c1 to c4.
* C22: Emulsion polymerization SBR-Cc: ESR emulsion polymerization SBR manufactured by JSR Corporation, trade name “# 1712” (37.5 parts by mass of oil-extended oil with respect to 100 parts by mass of SBR)

Examples c98 to c110 and comparative examples c9 to c15
Next, the compounding formulation shown in Table c10 and Table c11, the kneading time in the second stage of kneading and the kneading with a Banbury mixer after adjusting to the maximum temperature of the rubber composition, Examples c98 to c110 and Twenty kinds of rubber compositions of Comparative Examples c9 to c15 were prepared.
In the first stage of kneading the rubber compositions of Examples c98 to c110 and Comparative Examples c9 to c15, the rubber component (A), all or a majority of the carbon black (B), and other compounding agents were added and kneaded for 3 minutes. When the maximum temperature of the rubber composition reached 160 ° C., the rubber composition was discharged from the Banbury mixer.
Next, in the second stage of kneading of the rubber compositions of Examples c98 to c110, the compound (C) was added and kneaded as shown in Tables c10 and c11. The rubber compositions of Comparative Examples c9 to c13 did not have the second stage of kneading. The rubber compositions of Comparative Examples c14 and c15 were kneaded as shown in Table c11 without adding the compound (C) in the second stage of kneading.
The low exothermic properties (tan δ index) of the 20 types of rubber compositions obtained were evaluated by the above methods. The results are shown in Tables c10 and c11.

[note]
* C1 to * c22 are the same as Tables c1 to c9.
* C23: Solution polymerization SBR-Dc: Solution polymerization SBR manufactured by Asahi Kasei Co., Ltd., trade name “Toughden 3835” (37.5 parts by mass of oil-extended oil with respect to 100 parts by mass of SBR)
* C24: manufactured by Tosoh Silica Co., Ltd., trade name “Nip Seal AQ”, BET specific surface area 205 m ² / g
* C25: Bis (3-triethoxysilylpropyl) disulfide (average sulfur chain length: 2.35), silane coupling agent manufactured by Evonik, trade name “Si75” (registered trademark)

[note]
* C1 to * c13 are the same as Tables c1 to c4.
* C26: Natural rubber RSS # 3
* C27: Polybutadiene rubber manufactured by JSR Corporation, trade name “BR01”

As is apparent from Tables a1 to a11, each of the rubber compositions of Examples a1 to a107 has a low exothermic property (tan δ index) as compared with the rubber compositions to be compared in Comparative Examples a1 to a13. ) Was improved and excellent.
As is apparent from Tables b1 to b12, the rubber compositions of Examples b1 to b106 all have low exothermic properties (tan δ index) as compared with the rubber compositions to be compared in Comparative Examples b1 to b13. ) Was improved and excellent.
As is apparent from Tables c1 to c11, the rubber compositions of Examples c1 to c110 were all less heat-generating (tan δ index) than the rubber compositions to be compared in Comparative Examples c1 to c15. ) Was improved and excellent.

The rubber composition production method of the present invention can improve the low heat build-up of the rubber composition, so that it can be used for passenger cars, light trucks, light cars, light trucks and heavy vehicles {trucks and buses, off-the-road tires. Etc. (for construction vehicles, mining vehicles, etc.), etc., etc., and particularly suitable as a method for producing tread members (particularly tread grounding member) for pneumatic radial tires.

Claims

Compounding at least one compound (C) selected from a rubber component (A) selected from natural rubber and synthetic diene rubber, a filler containing carbon black (B), and a vulcanization accelerator. The rubber composition is kneaded in a plurality of stages, and all or one of the rubber component (A) and the carbon black (B) is kneaded in the first stage (X) of kneading. A method for producing a rubber composition, in which parts are kneaded and at least one compound (C) selected from the vulcanization accelerator is added and kneaded in a stage before the final stage of kneading.
In the first stage (X) of the kneading, the rubber component (A), all or part of the carbon black (B), and at least one compound (C) selected from the vulcanization accelerator are added and kneaded. The manufacturing method of the rubber composition of Claim 1.
After kneading all or part of the rubber component (A) and the carbon black (B) in the first stage (X) of the kneading, from the vulcanization accelerator in the middle of the first stage (X) The method for producing a rubber composition according to claim 2, wherein at least one selected compound (C) is added and further kneaded.
The rubber composition is kneaded in three or more kneading stages, and all or part of the rubber component (A) and the carbon black (B) are kneaded in the first stage (X) of the kneading. The rubber composition according to claim 1, wherein at least one compound (C) selected from the vulcanization accelerator is added and kneaded in the stage (Y) after the second stage and before the final stage. Manufacturing method.
The rubber composition according to any one of claims 1 to 4, wherein the compound (C) is at least one compound selected from sulfenamides, thiazoles, thiurams, dithiocarbamates, thioureas, and xanthogenic acids. Manufacturing method.
The method for producing a rubber composition according to any one of claims 1 to 5, wherein the maximum temperature in the first stage (X) is 150 to 190 ° C.
The method for producing a rubber composition according to any one of claims 1 to 6, wherein the kneading time in the first stage (X) is 3 to 15 minutes.
The method for producing a rubber composition according to any one of claims 4 to 7, wherein the maximum temperature of the rubber composition in the stage (Y) after the second stage of the kneading and before the final stage is 150 to 190 ° C. .
The method for producing a rubber composition according to any one of claims 4 to 8, wherein the kneading time in the stage (Y) after the second stage of the kneading and before the final stage is 2 to 15 minutes.
The method for producing a rubber composition according to any one of claims 3 and 5 to 7, wherein the temperature of the rubber composition when the compound (C) is added in the first stage (X) is 130 ° C or higher.
The method for producing a rubber composition according to any one of claims 1 to 10, wherein the rubber composition contains 70 to 100% by mass of carbon black (B) in the total amount of the filler.
The rubber according to any one of claims 5 to 11, wherein the sulfenamide is N-cyclohexyl-2-benzothiazolylsulfenamide and / or N-tert-butyl-2-benzothiazolylsulfenamide. A method for producing the composition.
The thiazole is at least one compound selected from 2-mercaptobenzothiazole, bis (4-methylbenzothiazolyl-2) -disulfide and di-2-benzothiazolyl disulfide. The manufacturing method of the rubber composition in any one of.
The method for producing a rubber composition according to any one of claims 5 to 11, wherein the thiuram is tetrakis (2-ethylhexyl) thiuram disulfide and / or tetrabenzyl thiuram disulfide.
The thiourea is at least one compound selected from thiourea, N, N′-diethylthiourea, trimethylthiourea, N, N′-diphenylthiourea and N, N′-dimethylthiourea. The manufacturing method of the rubber composition in any one of 11.
The dithiocarbamate is at least one compound selected from zinc dibenzyldithiocarbamate, zinc N-ethyl-N-phenyldithiocarbamate, zinc dimethyldithiocarbamate and copper dimethyldithiocarbamate. The manufacturing method of the rubber composition as described in above.
The method for producing a rubber composition according to any one of claims 5 to 11, wherein the xanthate is zinc isopropyl xanthate.