JP2015078271A - Method for producing rubber composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for producing a rubber composition the low heat generating property and durability of which can be improved.SOLUTION: There is provided the method for producing a rubber composition by blending a rubber component (A) composed of at least one kind of rubber selected from natural rubber and synthetic diene-based rubber, a filler (B') containing more than 70 mass% of carbon black having a nitrogen adsorption specific surface area (according to JIS K 6217-2:2001) of 70 to 110 m/g (B) and at least one kind of compound selected from a vulcanization accelerator (C). The method for producing a rubber composition includes mixing the rubber composition in a plurality of steps, and mixing the rubber component (A), all or a part of the carbon black (B) and the compound (C) in a first step of the mixing.

Description

  The present invention relates to a method for producing a rubber composition containing carbon black, which improves low heat buildup, aging resistance and crack growth resistance.

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 progresses, it has been desired that tires further improve both low heat buildup and durability.

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

  It is an object of the present invention to provide a method for producing a rubber composition capable of improving low heat buildup and durability, and in particular, a method for producing a rubber composition capable of improving low heat buildup, aging resistance and crack progress resistance. And

As a result of various experimental analyzes to solve the above problems, the present inventor has found that the reinforcing property of carbon black can be further improved by using a specific vulcanization accelerator, and the present invention has been completed. I came to let you.
That is, the present invention
[1] A rubber component (A) comprising at least one selected from natural rubber and synthetic diene rubber, and a nitrogen adsorption specific surface area (conforming to JIS K 6217-2: 2001) is 70 to 110 m ² / g. A method for producing a rubber composition comprising a filler (B ′) containing more than 70% by mass of carbon black (B) and at least one compound (C) selected from vulcanization accelerators. Kneading the rubber composition in a plurality of stages, and adding and kneading the rubber component (A), all or part of the carbon black (B), and the compound (C) in the first stage of kneading. And a rubber component (A) composed of at least one selected from natural rubber and synthetic diene rubber, and a nitrogen adsorption specific surface area (according to JIS K 6217-2: 2001). . And at least one compound (C) selected from a filler (B ′) containing 70 to 110% by mass of carbon black (B) having a mass of 70 to 110 m ² / g and a vulcanization accelerator. The rubber composition is produced by kneading the rubber composition in three or more kneading stages, and in the first stage (X) of kneading, all of the rubber component (A) and the carbon black (B). Alternatively, a part is kneaded, the compound (C) is added and kneaded in the stage (Y) after the second stage of the kneading and before the final stage, and the vulcanizing agent is added in the final stage (Z) of the kneading. A method of producing a rubber composition, characterized by kneading,
It is.

According to the present invention, it is possible to provide a method for producing a rubber composition capable of improving low heat buildup and durability.
In particular, it is possible to provide a method for producing a rubber composition that can improve low heat buildup, aging resistance, and crack growth resistance.

The present invention is described in detail below.
The first aspect of the method for producing a rubber composition of the present invention is a rubber component (A) comprising at least one selected from natural rubber and synthetic diene rubber, a nitrogen adsorption specific surface area (in accordance with JIS K 6217-2: 2001). And at least one compound (C) selected from a filler (B ′) containing more than 70% by mass of carbon black (B) having 70 to 110 m ² / g, and a vulcanization accelerator. A method for producing a rubber composition comprising blending, wherein the rubber composition is kneaded in a plurality of stages, and in the first stage of kneading, all or part of the rubber component (A) and the carbon black (B), And the compound (C) is added and kneaded.
In the present invention, the compound (C) is added and kneaded in the first stage of kneading to increase the low heat build-up of the rubber composition (reducing hysteresis loss) by enhancing the reinforcing property of the carbon black. Because.

  In the first aspect of the method for producing a rubber composition of the present invention, the compound (C) is added after kneading all or part of the rubber component (A) and the carbon black (B) in the first stage of kneading. Further, it is preferable to knead. Thereby, the dispersibility of carbon black (B) can be further improved, and a rubber composition with improved low heat generation can be obtained.

When all or part of the rubber component (A) and carbon black (B) is kneaded in the first stage of kneading and then the compound (C) is added during the first stage, the rubber component (A) and The time until the compound (C) is added in the middle of the first stage after kneading all or part of the carbon black (B) is preferably 10 to 300 seconds, preferably 10 to 180 seconds. Is more preferable, 30 to 180 seconds is further preferable, 30 to 150 seconds is still more preferable, and 30 to 120 seconds is particularly preferable. 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 order to set the above time to 10 to 300 seconds, for example, when the maximum temperature of the rubber composition in the first stage of kneading is 150 ° C. or higher, the compound is formed when the maximum temperature of the rubber composition reaches 140 ° C. When (C) is added and the maximum temperature of the rubber composition in the first stage of kneading is less than 150 ° C, the compound (C) may be added when the temperature becomes 10 ° C lower than the maximum temperature of the rubber composition.

The kneading step of the rubber composition in the present invention includes at least two stages of a first stage of kneading in which no other vulcanization accelerator except the compound (C) is blended and a final stage of kneading in which the vulcanizing agent is blended. If necessary, an intermediate stage of kneading in which no other vulcanizing agent other than the compound (C) is blended may be included.
The first stage of kneading in the first aspect of the present invention and the second aspect described later refers to the first stage of kneading the rubber component (A) and carbon black (B). It does not include a stage when kneading the rubber component (A) and a filler other than carbon black (B) or when pre-kneading only the rubber component (A) (for example, a natural rubber mastication stage).

  The kneading step of the rubber composition in the present invention includes at least two stages of a first stage of kneading in which no other vulcanization accelerator except the compound (C) is blended and a final stage of kneading in which the vulcanizing agent is blended. If necessary, an intermediate stage of kneading in which no other vulcanizing agent other than the compound (C) is blended may be included.

The second aspect of the method for producing a rubber composition of the present invention is a rubber component (A) comprising at least one selected from natural rubber and synthetic diene rubber, a nitrogen adsorption specific surface area (in accordance with JIS K 6217-2: 2001). And at least one compound (C) selected from a filler (B ′) containing more than 70% by mass of carbon black (B) having 70 to 110 m ² / g, and a vulcanization accelerator. A method for producing a rubber composition comprising blending, wherein the rubber composition is kneaded in three or more kneading stages, and the rubber component (A) and the carbon black (B ) In the second stage of the kneading and before the final stage (Y), the compound (C) is added and kneaded, and the vulcanizing agent in the final stage (Z) of the kneading. Is added and kneaded.

In the second aspect of the present invention, after the rubber component (A) and the carbon black (B) are all or partly kneaded in the first stage of kneading, after the second stage of kneading and the final stage. The compound (C) is added and kneaded in the earlier stage (Y) after the carbon black (B) is sufficiently 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 and the reinforcing property of the carbon black can be further enhanced. Thereby, the low exothermic property of a rubber composition can be made higher (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). It is preferable from the viewpoint of enhancing the properties. However, adding most of the carbon black to the second stage of kneading may not improve the dispersibility of the carbon black (B).

  The first stage of kneading in the first and second aspects of the present invention refers to the first stage of kneading the rubber component (A) and carbon black (B), and the rubber component (A ) And a filler other than carbon black (B), or a stage where only the rubber component (A) is preliminarily kneaded (for example, a natural rubber mastication stage) is not included.

In order to enhance the reinforcing property of the carbon black and improve the low heat buildup and wear resistance of the rubber composition, in the first aspect and the second aspect, the rubber composition in the first stage of kneading is used. The maximum temperature is preferably 140 to 190 ° C, more preferably 145 to 180 ° C, and further preferably 150 to 175 ° C.
Further, the kneading time in the first stage of kneading is preferably 1 to 15 minutes, more preferably 1 to 12 minutes, further preferably 1 to 9 minutes, and 1 from the viewpoint of productivity. Particularly preferred is ˜6 minutes. If the kneading time is 1 minute 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.

In order to improve the reinforcing property of the carbon black and improve the low heat build-up of the rubber composition, the stage (Y) after the second stage of the kneading according to the second aspect of the present invention and before the final stage (Y) The maximum temperature of the rubber composition is preferably 130 to 190 ° C, more preferably 140 to 190 ° C, still more preferably 140 to 180 ° C, and 145 to 175 ° C. Particularly preferred.
Further, the kneading time in the second stage of kneading is preferably 1 to 15 minutes, more preferably 1 to 12 minutes, further preferably 1 to 9 minutes, and 1 from the viewpoint of productivity. Particularly preferred is ˜6 minutes. If the kneading time is 1 minute 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.

  The kneading step of the rubber composition according to the second aspect of the present invention includes a first step of kneading including a filler containing the rubber component (A) and carbon black (B), and not compounding the compound (C), Step (Y) after and after the second stage of kneading in which C) is blended and no other vulcanization accelerator except compound (C) is blended, and the final stage of kneading in which the vulcanizing agent is blended In addition to the step (Y), other intermediate steps of kneading that do not contain a vulcanizing agent may be included as necessary. The kneading stage of the rubber composition according to the present invention preferably includes 3 to 8 stages, more preferably 3 to 6 stages, and still more preferably 3 to 5 stages. 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 (brominated butyl rubber (Br-IIR)). ), Chlorinated butyl rubber (Cl-IIR), halogenated copolymer of isobutylene and paramethylstyrene, etc.), ethylene-propylene-diene terpolymer rubber (EPDM), ethylene-butadiene copolymer rubber ( EBR), propylene-butadiene copolymer rubber (PBR), or the like can be used. Natural rubber and synthetic diene rubber may be used singly or as a blend of two or more.
In the present invention, belt portions and case members of pneumatic tires such as belt coating rubber, belt peripheral members (belt seat belt, belt end covering rubber, belt under cushion rubber, tread under cushion rubber, etc.), carcass ply coating rubber, etc. From the viewpoint of use, the rubber component (A) composed of natural rubber and one or more synthetic diene rubbers selected from styrene-butadiene copolymer rubber, polybutadiene rubber and polyisoprene rubber, or the rubber component of natural rubber alone ( A) is preferred.

[Filler (B ')]
The filler (B ′) used in the method for producing a rubber composition of the present invention is preferably composed only of carbon black (B), but if desired, as filler (B ′), in addition to carbon black (B) Thus, inorganic fillers such as silica and aluminum hydroxide can be used as long as they do not contradict the solution of the problems of the present invention.
From the viewpoint of achieving both low heat buildup and durability of the rubber composition, the rubber composition according to the present invention may contain more than 70% by mass of carbon black (B) in the total amount of the filler (B ′). The content is preferably 80% by mass or more, and more preferably 100% by mass of carbon black (B). The filler (B ′) 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)]
The carbon black (B) used in the method for producing a rubber composition according to the present invention has a nitrogen adsorption specific surface area (based on JIS K 6217-2: 2001) from the viewpoint of achieving both low heat buildup and reinforcing properties of carbon black. Is required to be 70 to 110 m ² / g. The nitrogen adsorption specific surface area is preferably 75 to 105 m ² / g from the viewpoint of ensuring the reinforcing property of carbon black.
Specific examples of the carbon black (B) include HAF, HAF-HS, HAF-LS, LI-HAF, N339, N351, IISAF, IISAF-HS, and ISAF-LS grade carbon black.
Carbon black (B) 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 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, thioureas, dithiocarbamates And at least one compound selected from xanthates.

  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-benzothiazolylsulfenamide Amide, N-propyl-2-benzothiazolylsulfenamide, N-butyl-2-benzothiazolylsulfenamide, N-pentyl-2-benzothiazolylsulfenamide, N-hexyl-2-benzothiazolyl Rusulfenamide, N-pentyl-2-benzothiazolylsulfenamide, N Octyl-2-benzothiazolylsulfenamide, N-2-ethylhexyl-2-benzothiazolylsulfenamide, N-decyl-2-benzothiazolylsulfenamide, N-dodecyl-2-benzothiazolylsulfen Amides, 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-benzothia Zolylsulfenamide, N, N-dipentyl-2-benzothiazolylsulfenamide N, N-dioctyl-2-benzothiazolylsulfenamide, N, N-di-2-ethylhexylbenzothiazolylsulfenamide, N-decyl-2-benzothiazolylsulfenamide, N, N-didodecyl- Examples include 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 carbon black.

  Examples of the thiazoles used in the method for producing a rubber composition of the present invention include 2-mercaptobenzothiazole, bis (4-methylbenzothiazolyl-2) -disulfide, di-2-benzothiazolyl disulfide, 2- Mercaptobenzothiazole zinc salt, 2-mercaptobenzothiazole cyclohexylamine 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, Examples include 2-mercapto-5-methoxybenzothiazole and 6-amino-2-mercaptobenzothiazole. Of these, 2-mercaptobenzothiazole, bis (4-methylbenzothiazolyl-2) -disulfide, and di-2-benzothiazolyl disulfide are preferable because of their high reactivity with carbon black.

  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 , Tetraethylthiu Mumonosulfide, tetrapropylthiuram monosulfide, tetraisopropylthiuram monosulfide, tetrabutylthiuram monosulfide, tetrapentylthiuram monosulfide, tetrahexylthiuram monosulfide, tetraheptylthiuram monosulfide, tetraoctylthiuram monosulfide, tetranonylthiuram monosulfide 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 carbon black.

  Examples of thioureas used in the method for producing the 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 preferable because of their high reactivity with carbon black.

  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, dibutyldithiocarbamate Sodium, sodium dipentyl dithiocarbamate, dihexyl dithioca Sodium rubamate, 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 dibenzyldithiocarbamate acid. Of these, zinc dibenzyldithiocarbamate, zinc N-ethyl-N-phenyldithiocarbamate, zinc dimethyldithiocarbamate and copper dimethyldithiocarbamate are preferred because of their high reactivity with carbon black.

  Examples of xanthates used in the method for producing a 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 tilxanthate, potassium 2-ethylhexylxanthate, potassium decylxanthate, potassium dodecylxanthate, sodium methylxanthate, sodium ethylxanthate, sodium propylxanthate, sodium butylxanthate, pentylxanthate Examples include sodium, sodium hexylxanthate, sodium heptylxanthate, sodium octylxanthate, sodium 2-ethylhexylxanthate, sodium decylxanthate, sodium dodecylxanthate, and the like. Of these, zinc isopropylxanthate is preferred because of its high reactivity with carbon black.

Compound (C) in the rubber composition in the first stage of kneading according to the method for producing a rubber composition of the present invention is added in an amount of 0.3 to 6.0 parts by mass with respect to 100 parts by mass of the rubber component (A). Preferably, 0.4 to 3.0 parts by mass are added, and more preferably 0.5 to 3.0 parts by mass are added. If it is 0.3 parts by mass or more, the reinforcing property of the carbon black can be improved, and if it is 6.0 parts by mass or less, excessive use can be avoided and it is economically advantageous 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 or the final stage, or in the intermediate stage between the first stage 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.

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.
In addition, low exothermic property (tan δ index), aging resistance and crack growth resistance were evaluated by the following methods.

(1) Low exothermic property (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. The reciprocal of tan δ of Comparative Examples 1, 2, 4, 5, 6, 7, 8, 9, or 10 was set to 100, and indexed by the following formula. 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 1, 2, 4, 5, 6, 7, 8, 9 or 10) / (tan δ of test vulcanized rubber composition)} × 100

(2) Aging resistance 200% elongation tensile stress of a sample of a vulcanized rubber composition kept at 100 ° C. and heat aged for 48 hours in a nitrogen-substituted sealed oven, and 200% elongation tensile stress before heat aging Is measured at 23 ° C. according to JIS K 6251: 2010 “Vulcanized Rubber and Thermoplastic Rubber—How to Obtain Tensile Properties”, and the 200% elongation tensile stress before thermal aging is defined as 100, and the 200% elongation tensile after thermal aging. Stress was expressed as an index. A larger index value indicates better aging resistance.
Aging resistance index = {(200% elongation tensile stress after thermal aging of test vulcanized rubber composition) / (200% elongation tensile stress before thermal aging of test vulcanized rubber composition)} × 100

(3) Crack Propagation Resistance According to JIS K 6270: 2010 "Vulcanized rubber and thermoplastic rubber-Determination of tensile fatigue properties-Constant strain method" (Number of repeated tensions until break) was measured, and the fatigue life of the vulcanized rubber composition of Comparative Examples 1, 2, 4, 5, 6, 7, 8, 9 or 10 was expressed as an index. The larger the index value, the better the crack resistance.
A dumbbell-shaped No. 3 test piece was used, the test strain was 100%, and the test frequency was 3 Hz.
Crack Propagation Resistance = {(Fatigue Life of Test Vulcanized Rubber Composition) / (Fatigue Life of Vulcanized Rubber Composition of Comparative Examples 1, 2, 4, 5, 6, 7, 8, 9 or 10)} × 100

Examples 1-41 and Comparative Examples 1-8
49 types of rubber compositions were prepared by adjusting the compounding formulations shown in Tables 1 to 12 and adjusting the kneading time and the maximum temperature of the rubber composition in the first stage of kneading and kneading with a Banbury mixer. .
In the first stage of kneading the rubber compositions of Examples 1-41, the rubber component (A), the carbon black (B), the compound (C) and other compounding agents were kneaded. In the first stage of kneading, all of carbon black (B) and compound (C) were added simultaneously.
In the first stage of kneading of the rubber compositions of Comparative Examples 1 to 8, all of the rubber component (A), carbon black (B), and other compounding agents were added, but the compound (C) was not added. Kneaded.
The 49 types of rubber compositions obtained were evaluated for low heat build-up (tan δ index) and abrasion resistance by the above methods. The results are shown in Tables 1 to 12.

[note]
* 1: Natural rubber: RSS # 4
* 2: Emulsion polymerization styrene-butadiene copolymer rubber manufactured by JSR Corporation, trade name “# 1500”
* 3: Carbon black-1: N330 manufactured by Asahi Carbon Co., Ltd., trade name “# 70” (nitrogen adsorption specific surface area: 77 m ² / g)
* 4: N- (1,3-dimethylbutyl) -N′-phenyl-p-phenylenediamine, manufactured by Ouchi Shinsei Chemical Co., Ltd., trade name “NOCRACK 6C”
* 5: N-cyclohexyl-2-benzothiazolylsulfenamide, manufactured by Ouchi Shinsei Chemical Co., Ltd., trade name “Noxeller CZ-G”
* 6: Vulcanization accelerator MBTS: Di-2-benzothiazolyl disulfide, manufactured by Sanshin Chemical Industry Co., Ltd., trade name “Sunceller DM”
* 7: Tetrakis (2-ethylhexyl) thiuram disulfide, manufactured by Ouchi Shinsei Chemical Industry Co., Ltd., trade name “Noxeller TOT-N”
* 8: N, N'-diethylthiourea, manufactured by Ouchi Shinsei Chemical Co., Ltd., trade name "Noxeller EUR"
* 9: Zinc dibenzyldithiocarbamate, manufactured by Ouchi Shinsei Chemical Co., Ltd., trade name “Noxeller ZTC”
* 10: Vulcanization accelerator TBBS: N-tert-butyl-2-benzothiazolylsulfenamide, manufactured by Sanshin Chemical Industry Co., Ltd., trade name “Sunseller NS”

[note]
* 1 to * 10 are the same as Table 1.

[note]
* 1 to * 10 are the same as Table 1.
* 11: Polybutadiene rubber manufactured by JSR Corporation, trade name “JSR BR01”

[note]
* 1- * 11 are the same as Tables 1-3.
* 12: 2-Mercaptobenzothiazole, manufactured by Ouchi Shinsei Chemical Co., Ltd., trade name “Noxeller MP”
* 13: Zinc salt of 2-mercaptobenzothiazole, manufactured by Ouchi Shinsei Chemical Co., Ltd., trade name “Noxeller MZ”
* 14: Bis (4-methylbenzothiazolyl-2) -disulfide, manufactured by NOCIL

[note]
* 1- * 11 are the same as Tables 1-3.
* 15: Tetrakis (benzyl) thiuram disulfide, manufactured by Sanshin Chemical Industry Co., Ltd., trade name “Sunseller TBZTD”

[note]
* 1- * 11 are the same as Tables 1-3.
* 16: Trimethylthiourea, manufactured by Sanshin Chemical Industry Co., Ltd., trade name "Sunseller TMU"
* 17: N, N'-diphenylthiourea, manufactured by Ouchi Shinsei Chemical Industry Co., Ltd., trade name "Noxeller C"

[note]
* 1- * 11 are the same as Tables 1-3.
* 18: Zinc N-ethyl-N-phenyldithiocarbamate, manufactured by Sanshin Chemical Industry Co., Ltd., trade name “Sunceller PX”
* 19: Zinc dimethyldithiocarbamate, manufactured by Sanshin Chemical Industry Co., Ltd., trade name “Sunseller PZ”
* 20: Copper dimethyldithiocarbamate, manufactured by Sanshin Chemical Industry Co., Ltd., trade name “Sunseller TT-CU”

[note]
* 1- * 11 are the same as Tables 1-3.
* 21: Zinc isopropylxanthate, manufactured by Ouchi Shinsei Chemical Co., Ltd., trade name “Noxeller ZIX-O”

[note]
* 1- * 15 are the same as Tables 1 and 3-5.
* 22: Vulcanization accelerator DZ: N, N-dicyclohexyl-2-benzothiazolylsulfenamide, manufactured by Ouchi Shinsei Chemical Industry Co., Ltd., trade name “Noxeller DZ”

[note]
* 1 to * 22 are the same as Table 9.
* 23: Carbon black-2: N326 manufactured by Asahi Carbon Co., Ltd., trade name “# 70L” (nitrogen adsorption specific surface area: 84 m ² / g)

[note]
* 1 to * 22 are the same as Table 9.
* 24: Carbon black-3: IISAF-HS manufactured by Tokai Carbon Co., Ltd., trade name “SEAST 5H” (nitrogen adsorption specific surface area: 99 m ² / g)

[note]
* 1 to * 22 are the same as Table 9.
* 25: Carbon Black-4: Product name “SB600” manufactured by Asahi Carbon Co., Ltd. (nitrogen adsorption specific surface area: 85 m ² / g)

Examples 42-50
Nine types of rubber compositions were prepared by adjusting the blending formulation shown in Table 13, the kneading time in the first stage of kneading, and the kneading with a Banbury mixer after adjusting to the maximum temperature of the rubber composition. In the first stage of kneading the rubber compositions of Examples 42 to 50, all of the rubber component (A), carbon black (B), compound (C) and other compounding agents were kneaded. In the first stage of kneading of the rubber compositions of Examples 42 to 45, all of the carbon black (B) and the compound (C) were simultaneously added and kneaded. Further, in the first stage of kneading the rubber compositions of Examples 46 to 50, after kneading all of the rubber component (A), carbon black (B) and other compounding agents, in the middle of this first stage. Compound (C) was added and further kneaded. In the first stage of the kneading of the rubber compositions of Examples 46 to 50, the compound (C) was added when the maximum temperature of the rubber composition reached 140 ° C., and further kneaded to obtain the maximum of the rubber composition in the first stage. The temperature was 150 ° C.
The nine rubber compositions obtained were evaluated for low heat build-up (tan δ index) and wear resistance by the above methods. The results are shown in Table 13. For comparison, Example 2 and Comparative Example 2 are also shown in Table 13.

[note]
* 1 to * 10 are the same as Table 1.

Examples 51 to 60 and Comparative Example 9
The blending prescription shown in Table 14 and the kneading time in the first stage of kneading and the kneading with a Banbury mixer adjusted so as to be the maximum temperature of the rubber composition, 11 types of Examples 51 to 60 and Comparative Example 9 A rubber composition was prepared.
In the first stage of the kneading of the rubber compositions of Examples 56 to 60 and Comparative Example 9, all of the rubber component (A), carbon black (B), and compounding agent other than the compound (C) were added and kneaded for 3 minutes. When the maximum temperature of the rubber composition reached 150 ° C., the rubber composition was discharged from the Banbury mixer.
Next, in the second stage of the kneading of the rubber compositions of Examples 56-60, the compound (C) was added and kneaded for 3 minutes. When the maximum temperature of the rubber composition reached 150 ° C., the rubber composition was discharged from the Banbury mixer. . In the second stage of the kneading of the rubber composition of Comparative Example 9, the kneading was carried out for 3 minutes without adding the compound (C), and the rubber composition was discharged from the Banbury mixer when the maximum temperature of the rubber composition reached 150 ° C.
Also, in the first stage of kneading the rubber compositions of Examples 51 to 55, all of the rubber component (A), carbon black (B), compound (C) and other compounding agents were added and kneaded for 3 minutes. When the maximum temperature of the rubber composition reached 150 ° C., the rubber composition was discharged from the Banbury mixer. In the first stage of kneading the rubber compositions of Examples 51 to 55, all of the carbon black (B) and the compound (C) were added simultaneously and kneaded. Further, in the second stage of kneading, kneading was carried out for 3 minutes without adding the compound (C), and the rubber composition was discharged from the Banbury mixer when the maximum temperature reached 150 ° C.
The low exothermic properties (tan δ index) of the 11 types of rubber compositions obtained were evaluated by the above methods. The results are shown in Table 14.

[note]
* 1 to * 10 are the same as Table 1.

Examples 61-70 and Comparative Example 10
The blending formulation shown in Table 15 and the kneading time in the first stage of kneading and the kneading with a Banbury mixer adjusted to the maximum temperature of the rubber composition, 11 types of Examples 61 to 70 and Comparative Example 10 A rubber composition was prepared.
In the first stage of the kneading of the rubber compositions of Examples 66 to 70 and Comparative Example 10, a compounding agent other than the rubber component (A), 35 parts by mass of carbon black (B), and compound (C) was added for 3 minutes. When kneaded and the maximum temperature of the rubber composition reached 150 ° C., it was discharged from the Banbury mixer.
Next, in the second stage of kneading of the rubber compositions of Examples 66 to 70, 15 parts by mass of carbon black (B) and compound (C) were added and kneaded for 3 minutes, and the maximum temperature of the rubber composition was 150 ° C. Then, it was discharged from the Banbury mixer. In the second stage of kneading the rubber composition of Comparative Example 10, 15 parts by mass of carbon black (B) was added and kneaded for 3 minutes without adding compound (C), so that the maximum temperature of the rubber composition was When it reached 150 ° C., it was discharged from the Banbury mixer.
In the first stage of kneading of the rubber compositions of Examples 61 to 65, 35 parts by mass of rubber component (A), carbon black (B), compound (C) and other compounding agents were added and kneaded for 3 minutes. When the maximum temperature of the rubber composition reached 150 ° C., the rubber composition was discharged from the Banbury mixer. In the first stage of kneading the rubber compositions of Examples 61 to 65, all of the carbon black (B) and the compound (C) were added simultaneously and kneaded. Further, in the second stage of kneading, 15 parts by mass of carbon black (B) was added and kneaded for 3 minutes without adding compound (C), and when the maximum temperature of the rubber composition reached 150 ° C., a Banbury mixer Discharged from.
The low exothermic properties (tan δ index) of the 11 types of rubber compositions obtained were evaluated by the above methods. The results are shown in Table 15.

[note]
* 1 to * 10 are the same as Table 1.

  As is clear from Tables 1 to 15, the rubber compositions of Examples 1 to 70 are all less heat-generating (tan δ index) than the rubber compositions to be compared in Comparative Examples 1 to 10. ), Aging resistance and crack growth resistance were improved and excellent.

  Since the rubber composition production method of the present invention can improve the low heat build-up of the rubber composition, the rubber composition obtained by the production method of the present invention can be used for passenger cars, small trucks, light trucks, and light trucks. And rubber compositions for belt parts and case members of various pneumatic tires for large vehicles (for trucks, buses, construction vehicles, etc.), especially belt coating rubber, belt peripheral members (inter-belt seat, belt end covering) Rubber, belt undercushion rubber, tread undercushion rubber, etc.) and carcass ply coating rubber, and preferably used as at least one rubber composition for tire members.

Claims (13)

A rubber component (A) comprising at least one selected from natural rubber and synthetic diene rubber, carbon black having a nitrogen adsorption specific surface area (according to JIS K 6217-2: 2001) of 70 to 110 m ² / g ( A method for producing a rubber composition comprising a filler (B ′) containing more than 70% by mass of B) and at least one compound (C) selected from vulcanization accelerators, comprising: The composition is kneaded in a plurality of stages, and the rubber component (A), all or part of the carbon black (B), and the compound (C) are added and kneaded in the first stage of kneading. A method for producing a rubber composition.   The method for producing a rubber composition according to claim 1, wherein the compound (C) is at least one compound selected from sulfenamides, thiazoles, thiurams, thioureas, dithiocarbamates and xanthates. .   The method for producing a rubber composition according to claim 1 or 2, wherein the maximum temperature of the rubber composition in the first stage is 140 to 190 ° C.   The method for producing a rubber composition according to any one of claims 1 to 3, wherein the kneading time in the first stage is 1 to 15 minutes.   The sulfenamide is at least one compound selected from N-cyclohexyl-2-benzothiazolylsulfenamide and N-tert-butyl-2-benzothiazolylsulfenamide. The manufacturing method of the rubber composition in any one.   5. 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 2 to 4, wherein the thiuram is tetrakis (2-ethylhexyl) thiuram disulfide and / or tetrabenzylthiuram disulfide.   The thiourea is at least one compound selected from thiourea, N, N'-diethylthiourea, trimethylthiourea, N, N'-diphenylthiourea and N, N'-dimethylthiourea. 5. A method for producing a rubber composition according to any one of 4 above.   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 2 to 4, wherein the xanthate is zinc isopropyl xanthate.   The method for producing a rubber composition according to any one of claims 1 to 10, wherein carbon black (B) is 100 mass% in the total amount of the filler (B ').   12. In the first step, after all or part of the rubber component (A) and the carbon black (B) are kneaded, the compound (C) is added and further kneaded. The manufacturing method of the rubber composition in any one of. A rubber component (A) comprising at least one selected from natural rubber and synthetic diene rubber, carbon black having a nitrogen adsorption specific surface area (according to JIS K 6217-2: 2001) of 70 to 110 m ² / g ( A method for producing a rubber composition comprising a filler (B ′) containing more than 70% by mass of B) and at least one compound (C) selected from vulcanization accelerators, comprising: The composition is kneaded in three or more stages of kneading, and the rubber component (A) and all or part of the carbon black (B) are kneaded in the first stage (X) of kneading, and the second and subsequent stages of kneading. And a method of producing a rubber composition, wherein the compound (C) is added and kneaded in the stage (Y) before the final stage, and the vulcanizing agent is added and kneaded in the final stage (Z) of the kneading. .