JP2012172120A - Rubber composition and pneumatic tire using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a rubber composition which has excellent low heat-generating properties and wear resistance by regulating the total amount of acidic components such as an organic acid such as stearic acid or an organic acid contained in a residue of an emulsifier added in a production process of emulsion-polymerized SBR (Styrene Butadiene Rubber) to the overall compounded rubber; and to provide a pneumatic tire having such characteristics, which is obtained by using the composition.SOLUTION: The rubber composition includes at least 10 pts.mass of a polymer component (B) containing a residue (A) of an organic acid added in a production process of a polymer as a rubber component; and 10-150 pts.mass, relative to 100 pts.mass of the rubber component, of a reinforcing filler (C). The sum of the residue (A) of the organic acid and an organic acid (D) used in compounding is 6 pts.mass or less.

Description

  The present invention relates to a rubber composition and a tire using the rubber composition. More specifically, the present invention relates to a rubber composition capable of reducing a hysteresis loss, providing a tire having good rolling resistance and excellent wear resistance, and a pneumatic tire using the rubber composition.

  In recent years, there has been a demand for improved wear resistance that leads to lower fuel consumption and resource saving of automobiles in connection with the global movement of carbon dioxide emission regulations due to social demands for energy saving and increased interest in environmental issues. Is becoming more severe. In order to meet such demands, a reduction in rolling resistance has also been demanded for tire performance. As a technique for reducing the rolling resistance of the tire, although a technique by optimizing the tire structure has been studied, the most common technique is to use a material having lower heat generation as the rubber composition.

  In order to obtain such a rubber composition having a low exothermic property, many technical developments have been made on modified rubbers for rubber compositions using silica or carbon black as a filler. Among them, a method in which the polymerization active terminal of a conjugated diene polymer obtained by anionic polymerization using organolithium is modified with an alkoxysilane derivative containing a functional group that interacts with a filler has been proposed as effective. (For example, see Patent Documents 1, 2, and 3).

  In addition, it is disclosed that in the emulsion polymerization of styrene-butadiene, the wear resistance is improved by limiting the amount of the emulsifier contained in the polymer to a specific range (1 to 3.5 phr) (for example, Patent Documents 4 and 5).

JP 2002-103925 A WO02 / 002356 brochure JP 2004-74960 A Special table 2003-521574 gazette Special table 2003-521575 gazette

  Under such circumstances, the present invention defines the total amount of acidic components such as organic acids, such as stearic acid, or emulsifier residues added in the production process of emulsion polymerization SBR in the entire compounded rubber. Accordingly, it is an object of the present invention to provide a rubber composition excellent in low heat buildup and wear resistance and a pneumatic tire having the above-described characteristics, using the composition.

As a result of intensive studies to achieve the above object, the present inventor has obtained an organic acid or an emulsion-polymerized styrene-butadiene rubber which is an acidic component such as stearic acid used as a vulcanization accelerating aid in the entire compounded rubber ( It has been found that the above object can be achieved by defining the total of the organic acids, which are acidic components contained in the residue of the organic acid added in the production process of the polymer such as E-SBR), as the entire blending system. The present invention has been completed based on such findings.
That is, the present invention
[1] The rubber component contains at least 10 parts by mass of the polymer component (B) containing the residue (A) of the organic acid added in the polymer production process, and a reinforcing filler with respect to 100 parts by mass of the rubber component 10 to 150 parts by mass of (C), a rubber composition characterized in that the sum of the organic acid residue (A) and the organic acid (D) used during compounding is 6 parts by mass or less,
[2] The rubber composition according to [1], wherein the component (A) is 3.5 parts by mass or less with respect to 100 parts by mass of the polymer component (B).
[3] The rubber composition according to the above [2], wherein 1.0 part by mass or less of the component (A) is included with respect to 100 parts by mass of the polymer component (B).
[4] The rubber composition according to any one of [1] to [3], wherein the component (B) is a synthetic diene polymer.
[5] The rubber composition according to [4], wherein the component (B) is a synthetic diene polymer obtained by emulsion polymerization,
[6] The rubber composition according to [5], wherein the component (B) is a styrene-butadiene copolymer (E-SBR) obtained by emulsion polymerization,
[7] The rubber composition according to [1], wherein the component (C) includes carbon black and / or silica,
[8] The rubber composition according to [7], wherein the component (C) includes less than 55 parts by mass of carbon black with respect to 100 parts by mass of the rubber component.
[9] The rubber composition according to [7], wherein the component (C) includes less than 40 parts by mass of silica,
[10] The rubber composition according to [1], wherein the component (D) includes fatty acids.
[11] The rubber composition according to [10], wherein the component (D) includes stearic acid,
[12] The rubber according to [1], wherein the residue of the organic acid added in the production process of the polymer of the component (A) includes at least one selected from fatty acids, resin acids, coal acids, and rosin acids. Composition,
[13] The residue of the organic acid added in the production process of the polymer of the component (A) includes a metal salt of a fatty acid, a metal salt of a resin acid, a metal salt of a carboxylic acid, and a metal salt of a rosin acid [ 1] rubber composition,
[14] The rubber composition according to the above [13], wherein the metal constituting the metal salt is an alkali metal or an alkaline earth metal,
[15] The rubber composition according to any one of [1] to [14], which is sulfur crosslinkable,
[16] In addition to the component (D), a compounding agent selected from sulfur, a vulcanization accelerator, a softener, a scorch inhibitor, an anti-aging agent, a tackifier, a foaming agent, a foaming aid, and a resin is blended. The rubber composition according to any one of [1] to [15] obtained above and [17] the rubber composition according to any one of [1] to [16] are used as a tread member or a sidewall member. Tire,
Is to provide.

According to the present invention, by prescribing the total amount of organic components such as an organic acid contained in an organic acid such as stearic acid or an emulsifier-polymerized SBR added in the production process of emulsion polymerization SBR in the entire compounded rubber, The low heat buildup and wear resistance of the pneumatic tire can be improved.
That is, low exothermic property and wear resistance can be improved by suppressing the amount of the acidic component used.

First, the rubber composition of the present invention will be described.
[Rubber composition]
The rubber composition of the present invention contains at least 10 parts by mass of a polymer component (B) containing a residue (A) of an organic acid added in the polymer production process as a rubber component, and relative to 100 parts by mass of the rubber component The reinforcing filler (C) is 10 to 150 parts by mass, and the total of the organic acid residue (A) and the organic acid (D) used during compounding is 6 parts by mass or less. .
Although it does not specifically limit about the lower limit of the said sum total, Usually, it is about 0.1 mass part. The effect of this invention can be show | played by prescribing | regulating the sum total of the residue (A) component of an organic acid and organic acid (D) component which occupies for the whole compounding system to the said range.
(A) The organic acid residue of a component is 3.5 mass parts or less with respect to 100 mass parts of polymer components (B), More preferably, it is 3.0 mass parts or less, More preferably, it is 1.0 mass part or less.
In addition, the sum of the components (A) and (D) includes at least 10 parts by mass of the polymer component (B) as a rubber component, and is 6 parts by mass or less, preferably 3.5 parts per 100 parts by mass of the rubber component. It is not more than part by mass, more preferably not more than 2.7 parts by mass, particularly preferably not more than 1.8 parts by mass.

(Residue of organic acid added in polymer production process (A))
Styrene butadiene rubber is used as a general-purpose synthetic rubber for tire treads. This polymerization method of styrene butadiene is an emulsion milk styrene butadiene rubber (E-SBR) polymerized with soap micelles using water as a medium, and solution polymerization styrene butadiene rubber (S-SBR) polymerized using a hydrocarbon compound as a medium. Broadly divided.
E-SBR is manufactured by an emulsion polymerization method in which styrene and butadiene are emulsified and copolymerized with soap using water as a medium. Depending on the polymerization temperature, it can be divided into a hot polymerization method and a cold polymerization method (redox catalyst). Currently, most of E-SBR is produced by the cold polymerization method.
In the cold polymerization method, the reaction is carried out at 5 ° C. to a polymerization rate of 60%. The use of disproportionated rosin acid soap as an emulsifier is a feature of the cold polymerization method, the polymerization rate is fast, the adhesiveness of rubber is improved, and the processability is excellent. However, due to the disadvantage that the rubber is colored, non-fouling rubbers are also widely used in combination with fatty acid soaps.
These soaps are contained as organic acid residues (A) in commonly used E-SBR. These organic acid residues (A) are not actively removed for the purpose of improving processability in the mixing step, and usually contain 4 to 8% of organic acids as residues.

On the other hand, solution polymerization diene rubber or the like usually does not contain the above residue. When solution polymerization diene rubber is used as the rubber composition, organic compounds such as stearic acid are usually used as vulcanization accelerators. Acid (D) is used as a compounding agent. When the diene rubber obtained by emulsion polymerization and the diene rubber obtained by solution polymerization are mixed and used as the rubber component, it is added at the time of compounding with the organic acid residue (A) added in the polymer production process. The organic acid (D) is also mixed, the total of the mixed (A) component and (D) component is controlled, and the organic acid residue (A) added in the polymer production process is effective. It is important to use it.
For example, when 50 parts by mass of (S-SBR) and 50 parts by mass of E-SBR are mixed as a rubber component, S-SBR contains no organic acid, but the residue of organic acid in E-SBR (A ) Is converted to 100 parts by mass of the rubber component, and the organic acid is within the range of 0.1 to 6 parts by mass, the compounding system can be used without newly adding stearic acid as a vulcanization acceleration aid. Within this range, the organic acid of component (A) can be used as a vulcanization acceleration aid.
Moreover, if the sum total of the quantity of (D) component and the quantity of (A) component exists in the range of 0.1-6 mass parts, it is in the range of this invention.

(Polymer component (B))
The amount of the organic acid residue (A) added in the polymer production step is preferably 3.5 parts by mass or less, and 1.0 part by mass or less with respect to 100 parts by mass of the polymer component (B). It is more preferable. Although there is no restriction | limiting in particular about the lower limit, Usually, it is about 0.1 mass part.
By setting the content of the component (A) relative to 100 parts by mass of the polymer component (B) within the above range, the low heat build-up of the rubber composition can be ensured and the wear resistance can be improved.

The polymer component (B) is preferably a synthetic diene polymer.
Examples of the conjugated diene compound include 1.3-butadiene; isoprene: 1.3-pentadiene: 2,3-dimethyl-1,3-butadiene: 2-phenyl-1,3-butadiene: 1, 3-hexadiene, and the like. Can be mentioned. These may be used alone or in combination of two or more, and among these, 1,3-butadiene, isoprene and 2,3-dimethyl-1,3-butadiene are particularly preferred.
Moreover, as an aromatic vinyl compound used for copolymerization with these conjugated diene compounds, for example, styrene: α-methylstyrene: 1-vinylnaphthalene; 3-vinyltoluene; ethylvinylbenzene: divinylbenzene: 4-cyclohexene Xylstyrene; 2,4,6-trimethylstyrene and the like. These may be used alone or in combination of two or more, but among these, styrene is particularly preferred.
As described above, the polymer component (B) is more preferably a styrene butadiene copolymer (E-SBR), which is a synthetic diene polymer obtained by emulsion polymerization by a cold polymerization method.

(Reinforcing filler (C))
The rubber composition of the present invention preferably contains silica and / or carbon black as a reinforcing filler.
The silica is not particularly limited, and can be arbitrarily selected from those conventionally used as reinforcing fillers for rubber.
Examples of the silica include wet silica (hydrous silicic acid), dry silica (anhydrous silicic acid), calcium silicate, aluminum silicate, and the like. Wet silica that is noticeable is preferred.

Carbon black is not particularly limited, and for example, SRF, GPF, FEF, HAF, 1SAF, SAF, etc. are used, iodine adsorption (IA) is 60 mg / g or more, and dibutyl phthalate oil absorption (DBP) is 80 ml / 100 g. The above carbon black is preferable.
By using carbon black, the effect of improving grip performance and fracture resistance is increased, but HAF, ISAF, and SAF, which are excellent in wear resistance, are particularly preferable.
One type of silica and / or carbon black may be used, or two or more types may be used in combination.

  Silica and / or carbon black is required to be blended in an amount of 10 to 150 parts by mass with respect to 100 parts by mass of the rubber component. Further preferred. By making the amount of carbon black and / or silica in the above range, excellent workability such as kneading workability can be obtained, and desired abrasion resistance can be obtained as a rubber composition.

In the rubber composition of the present invention, when silica is used as the reinforcing filler, a silane coupling agent can be blended for the purpose of further improving the reinforcement and low heat build-up.
Examples of the silane coupling agent include bis (3-triethoxysilylpropyl) tetrasulfide, bis (3-triethoxysilylpropyl) trisulfide, bis (3-triethoxysilylpropyl) disulfide, and bis (2- 卜). Ethoxysilylethyl) tetrasulfide, bis (3-trimethoxysilyl) propyl) tetrasulfide, bis (2-trimethoxysilylethyl) tetrasulfide, 3-mercaptopropyltrimethoxysilane, 3-mercaptopropyltriethoxysilane, 2- Mercaptoethyltrimethoxysilane, 2-mercaptoethyltriethoxysilane, 3-trimethoxysilylpropyl-N, N-dimethylthiocarbamoyl tetrasulfide, 3-triethoxysilylpropyl-N, N-dimethylthio Carbamoyl tetrasulfide, 2-triethoxysilylethyl-N, N-dimethylthiocarbamoyl tetrasulfide, 3-trimethoxysilylpropylbenzothiazolyl tetrasulfide, 3-triethoxysilylpropylbenzoyl tetrasulfide, 3-triethoxy Silylpropyl methacrylate monosulfide, 3-trimethoxysilylpropyl methacrylate monosulfide, bis (3-diethoxymethylsilylpropyl) tetrasulfide, 3-mercaptopropyldimethoxymethylsilane, dimethoxymethylsilylpropyl-N, N-dimethylthiocarbamoyltetra Sulfide, dimethoxymethylsilylpropyl benzothiazolyl tetrasulfide, etc. are mentioned. Among these, from the point of reinforcement improvement effect, Scan (3-triethoxysilylpropyl) polysulfide and 3-trimethoxysilylpropyl benzothiazyl tetrasulfide are preferable.
One of these silane coupling agents may be used alone, or two or more thereof may be used in combination.

(Organic acid used during compounding (D))
Higher fatty acids are generally used in the rubber industry as the organic acid (D) component used at the time of blending, and stearic acid used as a vulcanization accelerator is particularly preferred.
The above vulcanization accelerator is used in combination with metal oxide (mainly zinc white) and fatty acid (mainly stearic acid) in the sulfur vulcanization system to activate the vulcanization accelerator and vulcanize (crosslink) Used to improve efficiency.

Fatty acids, resin acids (rosin acid), and coal acids are used as the residue of the organic acid added as an emulsifier in the production process of the polymer of component (A).
Fatty acids include fatty acid soaps such as capric acid, lauric acid, myristic acid, palmitic acid, stearic acid or oleic acid; resin acids (known as rosin acids) include abietic acid, neoabietic acid, parast Examples thereof include compounds containing an organic acid such as phosphoric acid, pimaric acid, isopimaric acid or dehydroabietic acid. Among these, the resin acid is a natural resin acid contained in tall rosin, gum rosin, and wood rosin, and the emulsifier used for the synthesis of the E-SBR is mainly rosin acid soap alone or a mixed soap of rosin acid and fatty acid. Used. Moreover, phenolic resins are mentioned as coalic acids.

Moreover, the residue of the organic acid added in the production process of the polymer of the component (A) is used as an emulsifier, and includes a metal salt of a higher fatty acid having 12 or more carbon atoms, a metal salt of a resin acid (a metal salt of a rosin acid) ), Metal salts of carboxylic acids can also be used. The metal constituting the metal salt is an alkali metal or an alkaline earth metal. In particular, as an emulsifier for synthetic rubber, disproportionated rosin acid soap is used, and alkali metal sodium salts and potassium salts are used.
However, in order to achieve the object of the present invention (low exothermic property and improvement of body wear), it is preferable that the amount of the organic acid residue (A) component contained in E-SBR is small.

The rubber composition of the present invention is sulfur crosslinkable, and sulfur, a vulcanization accelerator, and a vulcanization acceleration aid are blended as a vulcanization system. Among them, the vulcanization acceleration aid activates the vulcanization accelerator and further accelerates the acceleration reaction. There are metal oxides typified by zinc oxide (zinc white) and fatty acids typified by stearic acid, both of which are necessarily blended in the case of a diene rubber.
In the present invention, the stearic acid is used as a typical organic acid (D) used at the time of blending.

(Other rubber components (E))
The rubber component other than the polymer component (B) is preferably a solution-polymerized diene synthetic rubber, natural rubber or the like. Examples of the solution-polymerized diene-based synthetic rubber include polybutadiene rubber (BR), styrene butadiene copolymer rubber (SBR), and polyisoprene rubber. These solution-polymerized diene-based synthetic rubbers are usually unmodified, but modified diene-based rubbers can also be preferably used.
When natural rubber is used as the other rubber component, the organic acid contained in the natural rubber can be added to the calculation as an organic acid contained in the entire compounding system. Natural rubber can also be preferably used as the other rubber component as long as the total is within the range specified in the present invention.

(Preparation and use of rubber composition)
In the rubber composition according to the present invention, various chemicals usually used in the rubber industry, for example, sulfur, vulcanization accelerator, softener, process oil, anti-aging, as long as the effects of the present invention are not impaired. An agent, an anti-scorch agent, zinc white, an anti-adhesive agent, a foaming agent, a foaming aid and a resin can be contained.
Further, the rubber composition of the present invention is obtained by kneading using a kneader such as an open kneader such as a roll, a closed kneader such as a Banbury mixer, and vulcanized after molding. Applicable to various rubber products. For example, it can be used for tire applications such as tire treads, under treads, carcass, sidewall side reinforcing rubber and bead fillers, but especially for low fuel consumption with excellent balance of low heat build-up, wear resistance and breaking strength It is suitably used as a tread rubber for tires, large tires, and high performance tires.

[tire]
The tire of the present invention is characterized in that the above-described sulfur crosslinkable rubber composition of the present invention is used for a tire member. As the tire member, a tread, a base tret, a sidewall, a side reinforcing rubber, and a bead filler can be preferably mentioned, and the sulfur crosslinkable rubber composition of the present invention can be used for any of these. It is preferable to use for.
A tire using the sulfur crosslinkable rubber composition of the present invention for a tread has low rolling resistance and excellent fuel efficiency, and also has excellent fracture characteristics and wear resistance. In addition, as gas with which the tire of the present invention is filled, normal or air with a changed oxygen partial pressure, or an inert gas such as nitrogen is exemplified. When the rubber composition of the present invention is used for a tread, for example, it is extruded on a tread member, and is pasted and molded by a usual method on a tire molding machine to form a raw tire. The green tire is heated and pressed in a vulcanizer to obtain a tire.

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 loss tangent (tan δ) and abrasion resistance of the vulcanized rubber composition and the amount of organic acid remaining in E-SBR were measured and evaluated by the following methods.
(1) Loss tangent (tan δ)
Using a dynamic spectrometer manufactured by Rheometrics, Inc., measurement was performed under the conditions of tensile dynamic strain of 1%, frequency of 10 Hz, and 50 ° C., and the reciprocal of tan δ of the control was expressed as an index. It shows that it is excellent in low exothermic property, so that the value of an index | exponent is large. The measurement results are shown in Table 2.
(2) Abrasion resistance Using a Ramborn-type abrasion tester, the amount of abrasion with a slip rate of 25% at room temperature was measured, and the reciprocal of the amount of abrasion of the control was represented as an index. It shows that it is excellent in abrasion resistance, so that an index | exponent is large. The measurement results are shown in Table 2.
(3) Measurement of the amount of organic acid in E-SBR It was measured according to JIS K6237: 2001. Non-oil-extended SBR # 1500 used in the examples contained 6.39 parts by mass of organic acid.

Production Example 1
<Production of solution polymerization S-SBR>
Add 1,3-butadiene in cyclohexane and styrene in cyclohexane to a dry, nitrogen-substituted 800 mL pressure-resistant glass container so that 1,3-butadiene 60 g and styrene 15 g are added, and 2,2-ditetrahydrofuryl is added. After adding 0.70 mmol of propane and further adding 0.70 mmol of n-butyllithium (BuLi), a polymerization reaction was performed in a hot water bath at 50 ° C. for 1.5 hours. The polymerization conversion rate at this time was almost 100%.
<Post-polymerization treatment>
Next, an isopropanol solution of 2,6-di-tert-butyl-p-cresol (BHT) was added to the polymerization reaction system to stop the polymerization reaction. Then, it vacuum-dried and solution polymerization SBR (S-SBR) was obtained. The resulting solution polymerized S-SBR had a bound styrene content of 20% and a bound vinyl content of the butadiene portion of 55%.

Production Example 2
E-SBRs with different emulsifier amounts were prepared based on the following formulation.
About 0.5 kg of commercially available E-SBR "SBR # 1500: styrene content 23.5%, emulsifier rosin acid soap" containing 6.39 parts by mass of organic acid residue per 100 parts by mass of rubber component, lower part of container Place in a 20 liter cylindrical stainless steel container with a ball valve on the side, add 10 liters of special grade cyclohexane made by Kanto Chemical Co., and evenly with a mixer stirrer equipped with a Teflon (registered trademark) winged shaft Until dissolved. While stirring this solution, 0.1N KOH aqueous solution was added, and the pH of the aqueous phase was adjusted to be between 10-11. After stirring this liquid for 13 hours, stirring was stopped and it left still. After the water phase and the organic phase were roughly separated, the water phase was discharged from the ball valve at the bottom of the stainless steel container. Next, after adding about 3 liters of ion-exchanged water to the organic phase of the container and stirring for 30 minutes, the operation of discharging the aqueous phase was repeated 5 times to discharge the organic acid component from the organic phase. In repeating this extraction operation, at the time of adding ion exchange water five times, 0.1N sulfuric acid was added so that the pH of the aqueous phase was 5 to 6, and the aqueous phase was discharged after stirring for 30 minutes. Thereafter, 1 gram of the anti-aging agent 6PPD was added to the organic phase in the container and sufficiently stirred. Thereafter, the solvent was distilled off by a conventional method, and the obtained solid was dried in a vacuum oven at 60 ° C. for 2.5 hours to obtain E-SBR- (1). As a result of measuring the organic acid contained in the dried polymer, 0.47 parts by mass of organic acid residue was contained.

Production Example 3
E-SBR- (2) was obtained in the same manner as in Production Example except that extraction with ion-exchanged water was performed three times. As a result of measuring the amount of organic acid contained in the dried polymer, 1.24 parts by mass of organic acid residue was contained.

Production Example 4
E-SBR- (3) was obtained in the same manner as in Production Example except that extraction with ion-exchanged water was performed twice. As a result of measuring the amount of organic acid contained in the dried polymer, it contained 2.21 parts by mass of organic acid residue.

Production Example 5
E-SBR- (4) was obtained in the same manner as in Production Example except that extraction with ion-exchanged water was performed once. As a result of measuring the amount of organic acid contained in the polymer after drying, it contained 3.82 parts by mass of organic acid residue.

Preparation of rubber composition Table 1 shows S-SBR obtained in Production Example 1, E-SBR obtained in Production Examples 2 to 5 and "E-SBR # 1500" manufactured by JSR Corporation as rubber components. Each rubber composition was prepared based on the composition shown in FIG.
The rubber component (B), rubber component (E), organic acid residue (A) and stearic acid (D) were blended based on the descriptions in Tables 2 to 6.

"note"
* 1. Carbon black: HAF (N330), "Asahi # 70" manufactured by Asahi Carbon Co.
* 2. Silica: Trademark “Nipsil AQ” made by Tosoh Silica
* 3. Silane coupling agent: bis (3-triethoxysilylpropyl) tetrasulfide, manufactured by Degussa, trademark “Si69”
* 4. Anti-aging agent: 6C (N- (1,3-dimethylbutyl) -N′-phenyl-p-phenylenediamine, “NOCRACK 6C” manufactured by Ouchi Shinsei Chemical Co., Ltd.)
* 5. Vulcanization accelerator DPG: Diphenylguanidine, "Noxeller D" manufactured by Ouchi Shinsei Chemical Industry Co., Ltd.
* 6. Vulcanization accelerator DM: Dibenzothiazyl disulfide, “Noxeller DM” manufactured by Ouchi Shinsei Chemical Co., Ltd.
* 7. : Vulcanization accelerator CZ: (N-cyclohexyl-2-benzothiazylsulfenamide, “Noxeller CZ” manufactured by Ouchi Shinsei Chemical Co., Ltd.

Examples 1-4, Comparative Example 1
(A) With respect to 100 parts by mass of the polymer component (B) having different organic acid residues, 1.3 parts by mass of stearic acid as the component (D) was blended to evaluate tan δ (low heat build-up) and abrasion resistance. The evaluation results are shown in Table 2.

Examples 5-8, Comparative Example 2
(A) 80 parts by mass of the polymer component (B) having different organic acid residues, 20 parts by mass of the other polymer component (E), and 1.3 parts by mass of stearic acid as the component (D) for a total of 100 parts by mass. , Tan δ (low exothermic property) and abrasion resistance were evaluated. The evaluation results are shown in Table 3.

Examples 9 to 10, Comparative Example 3
(A) 20 parts by mass of polymer component (B) having different organic acid residue, 80 parts by mass of other polymer component (E), and 100 parts by mass in total, 5.0 parts by mass of stearic acid as component (D) , Tan δ (low exothermic property) and abrasion resistance were evaluated. The evaluation results are shown in Table 4.

Examples 11-13, Comparative Example 4
(A) With respect to 100 parts by mass of the polymer component (B) having 0.47 parts by mass of the organic acid residue, the stearic acid of the (D) component was varied, and tan δ (low heat build-up) and abrasion resistance were evaluated. The evaluation results are shown in Table 5.

Examples 14-17, Comparative Example 5
(A) With respect to 100 parts by mass of the polymer component (B) having different organic acid residues, tan δ (low exothermic property) and abrasion resistance were evaluated without blending the stearic acid as the component (D). The evaluation results are shown in Table 6.

  As shown in Tables 2 to 6, it can be seen that the examples of the present invention are excellent in low heat generation (tan δ) and wear resistance as compared with the comparative examples. In particular, it can be seen that the component (A) is 1.0 part by mass or less, and that the sum of the component (A) and the component (D) is 1.8 parts by mass or less is excellent in both performances.

The rubber composition of the present invention regulates the total amount of acidic components such as organic acids such as stearic acid or emulsifier added in the production process of emulsion polymerization SBR in the entire compounded rubber. Can provide a tire having low heat build-up and excellent wear resistance.
Since the tire of the present invention has the above properties, it is suitable for various pneumatic tires such as radial tires for passenger cars, radial tires for light passenger cars, radial tires for light trucks, radial tires for trucks and buses, and tires for construction vehicles. Used.

Claims (17)

  The rubber component contains at least 10 parts by mass of the polymer component (B) containing the organic acid residue (A) added in the polymer production process, and the reinforcing filler (C) with respect to 100 parts by mass of the rubber component 10 to 150 parts by mass, and the total of the organic acid residue (A) and the organic acid (D) used during compounding is 6 parts by mass or less.   The rubber composition according to claim 1, wherein the component (A) is contained in an amount of 3.5 parts by mass or less with respect to 100 parts by mass of the polymer component (B).   The rubber composition according to claim 2, wherein 1.0 part by mass or less of the component (A) is contained with respect to 100 parts by mass of the polymer component (B).   The rubber composition according to claim 1, wherein the component (B) is a synthetic diene polymer.   The rubber composition according to claim 4, wherein the component (B) is a synthetic diene polymer obtained by emulsion polymerization.   The rubber composition according to claim 5, wherein the component (B) is a styrene-butadiene copolymer (E-SBR) obtained by emulsion polymerization.   The rubber composition according to claim 1, wherein the component (C) contains carbon black and / or silica.   The rubber composition according to claim 7, wherein the component (C) contains less than 55 parts by mass of carbon black with respect to 100 parts by mass of the rubber component.   The rubber composition according to claim 7, wherein the component (C) contains less than 40 parts by mass of silica.   The rubber composition according to claim 1, wherein the component (D) contains fatty acids.   The rubber composition according to claim 10, wherein the component (D) contains stearic acid.   The rubber composition according to claim 1, wherein the residue of the organic acid added in the production process of the polymer of the component (A) contains at least one selected from fatty acids, resin acids, coal acids, and rosin acids. .   The residue of the organic acid added in the production process of the polymer of the component (A) includes a metal salt of a fatty acid, a metal salt of a resin acid, a metal salt of a carboxylic acid, or a metal salt of a rosin acid. Rubber composition.   The rubber composition according to claim 13, wherein the metal constituting the metal salt is an alkali metal or an alkaline earth metal.   It is sulfur crosslinkable, The rubber composition in any one of Claims 1-14.   Other than the component (D), sulfur, a vulcanization accelerator, a softener, a scorch inhibitor, an anti-aging agent, a tackifier, a foaming agent, a foaming aid, and a compounding agent selected from resins are blended. The rubber composition according to any one of claims 1 to 15.   A tire using the rubber composition according to any one of claims 1 to 16 as a tread member or a side wall member.