JP2014031419A - Rubber composition and tire using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a rubber composition capable of preventing degradation in ozone resistance and discoloration by an amine age resister and/or wax when the rubber composition is used for a tread part of a tire.SOLUTION: The rubber composition is prepared by compounding at least one kind of rubber component selected from a diene synthetic rubber and/or a natural rubber and at least one kind of nonionic surfactant selected from compounds expressed by formula (I). In formula (I), R1 represents an alkyl group or an alkenyl group having 1 to 21 carbon atoms, in which the alkyl group or the alkenyl group may be any of straight-chain, branched-chain and cyclic groups; and n is 10 to 24.

Description

  The present invention relates to a rubber composition and a tire using the rubber composition, which can improve browning of a tire outer rubber, and can be suitably used particularly for a tread rubber and the rubber composition. Related to the tire.

  In general, a rubber article made from natural rubber or a diene synthetic rubber is deteriorated in the presence of ozone, and a crack occurs on the surface. This crack progresses due to static and dynamic stress applied to the rubber article, and as a result, the rubber article is broken.

  In order to suppress the occurrence and progress of cracks due to ozone, the rubber article has an anti-aging agent such as N- (1,3-dimethylbutyl) -N′-phenyl-p-phenylenediamine as an anti-aging agent. A rubber composition containing an agent is applied. The rubber composition contains a wax for forming a protective film on the surface of the rubber article for the purpose of static protection from ozone.

  However, although the amine-based anti-aging agent and the wax are effective in suppressing the generation and progress of cracks in the presence of ozone, they are easy to move through a polymer substrate such as a rubber component, and in a short period, particularly rubber articles, It shifts to the surface of the tire and deteriorates the appearance by changing the color of the rubber article during storage and use. Here, when the wax moves to the surface, the surface turns white, and when the amine-based anti-aging agent moves to the surface, the surface turns brown.

  In contrast, a rubber composition for a tire sidewall is disclosed a technique for preventing discoloration due to an amine anti-aging agent and wax by blending a polyoxyethylene ether type nonionic surfactant or a sorbitan type surfactant. (Patent Document 1, Patent Document 2). However, these techniques cannot sufficiently prevent the discoloration of the tread rubber composition.

JP-A-5-194790 JP 2004-307812 A

  Therefore, the problem of the present invention is to prevent discoloration due to an anti-aging agent (particularly an amine-based anti-aging agent) and / or wax without deteriorating ozone resistance by using it in the tread portion of the tire, An object of the present invention is to provide a rubber composition capable of maintaining a good appearance and a tire using the rubber composition.

  As a result of intensive studies to solve the above-mentioned problems, the present inventors use a non-ionic surfactant having a specific structure in the rubber component, thereby deteriorating ozone resistance for use in the tread portion of the tire. Thus, the present inventors have found that a rubber composition capable of preventing discoloration due to an amine-based antioxidant and / or wax can be obtained, and the present invention has been completed.

［式（Ｉ）において、Ｒは、炭素数１〜２１のアルキル基又はアルケニル基を表し、該アルキル基及び該アルケニル基は直鎖状、分枝鎖状及び環状のいずれでもよく、ｎは１０〜２４である。］
［２］ 前記ゴム成分１００質量部に対し、前記非イオン系界面活性剤０．１〜１０質量部を配合してなる請求項１に記載のゴム組成物、
［３］ さらに、ワックスを配合してなる上記［１］又は［２］に記載のゴム組成物、
［４］ さらに、老化防止剤を配合してなる上記［１］〜［３］のいずれかに記載のゴム組成物、
［５］ 前記老化防止剤がアミン系老化防止剤である上記［４］に記載のゴム組成物、
［６］ 上記［１］〜［５］のいずれかに記載のゴム組成物をタイヤ外皮に適用したタイヤ、
［７］ タイヤ外皮がトレッド部である上記［６］に記載のタイヤ、及び
［８］ ジエン系合成ゴム及び天然ゴムから選択される少なくとも一種のゴム成分に、下記式（Ｉ）で表される化合物から選択される少なくとも一種の非イオン系界面活性剤を配合することを特徴とするゴム組成物の変色防止方法。

［式（Ｉ）において、Ｒは、炭素数１〜２１のアルキル基又はアルケニル基を表し、該アルキル基及び該アルケニル基は直鎖状、分枝鎖状及び環状のいずれでもよく、ｎは１０〜２４である。］
を提供するものである。 That is, the present invention
[1] A blend of at least one rubber component selected from diene synthetic rubber and natural rubber, and at least one nonionic surfactant selected from compounds represented by the following formula (I). A rubber composition characterized by

[In Formula (I), R represents an alkyl group or an alkenyl group having 1 to 21 carbon atoms, and the alkyl group and the alkenyl group may be linear, branched or cyclic, and n is 10 ~ 24. ]
[2] The rubber composition according to claim 1, wherein 0.1 to 10 parts by mass of the nonionic surfactant is blended with 100 parts by mass of the rubber component.
[3] The rubber composition according to [1] or [2], further comprising a wax.
[4] The rubber composition according to any one of [1] to [3], further comprising an antioxidant.
[5] The rubber composition according to [4], wherein the anti-aging agent is an amine-based anti-aging agent,
[6] A tire in which the rubber composition according to any one of [1] to [5] is applied to a tire skin,
[7] The tire according to the above [6], wherein the tire skin is a tread portion, and [8] at least one rubber component selected from diene-based synthetic rubber and natural rubber is represented by the following formula (I): A method for preventing discoloration of a rubber composition, comprising blending at least one nonionic surfactant selected from compounds.

[In Formula (I), R represents an alkyl group or an alkenyl group having 1 to 21 carbon atoms, and the alkyl group and the alkenyl group may be linear, branched or cyclic, and n is 10 ~ 24. ]
Is to provide.

  According to the present invention, an anti-aging agent (especially an amine-based anti-aging agent) can be used without blending a rubber component with a non-ionic surfactant having a specific structure and using it in a tread portion of a tire without deteriorating ozone resistance. ) And / or a rubber composition capable of preventing discoloration due to wax, and a tire using the rubber composition. Furthermore, the discoloration prevention method which can prevent discoloration of this rubber composition can be provided.

The present invention is described in detail below.
The rubber composition of the present invention comprises at least one rubber component selected from diene synthetic rubber and natural rubber, and at least one nonionic surfactant selected from the compound represented by the formula (I). It is characterized by blending.
Here, “mixing” preferably includes at least a step of kneading the rubber component and the nonionic surfactant after mixing them.
The browning of the tire hull is caused by the anti-aging agent and the wax passing through the polymer substrate such as a rubber component to the tire surface, and the wax deposits on the surface of the tire to form an uneven surface and light scattering occurs. The anti-aging agent adhering to the oxidant is oxidized to become a coloring component, so that the tea looks discolored.
In the rubber composition of the present invention, the nonionic surfactant represented by the above formula (I) improves the light scattering state by smoothing the uneven surface of the wax deposited on the surface, thereby improving the light scattering state. Improve weirdness. That is, the nonionic surfactant is adjusted to have a suitable length with the rubber composition by adjusting the length of the hydrophobic group R ^{2 and} the length of the hydrophilic group (R ¹ O) _n to control the compatibility with the rubber composition. Therefore, it is deposited on the tire surface and exhibits the above function.
Here, in the rubber composition of the present invention, the amount of the nonionic surfactant is preferably 0.1 to 10 parts by mass, and 0.5 to 7 parts by mass with respect to 100 parts by mass of the rubber component. More preferably, it is 0.5-5 mass parts, More preferably, it is 1-5 mass parts. If it is 0.1 parts by mass or more, the effect of preventing discoloration due to an anti-aging agent (particularly an amine-based anti-aging agent) or wax is increased. It can suppress suitably that glossiness comes out and an external appearance worsens, and a problem arises in surface adhesiveness and workability | operativity deteriorates.
Moreover, ozone resistance does not fall by adding this surfactant.

Examples of the rubber component used in the rubber composition of the present invention include diene-based synthetic rubber and natural rubber. Examples of the diene-based synthetic rubber include isoprene rubber (IR), polybutadiene rubber (BR), and styrene-butadiene copolymer. Examples thereof include rubber (SBR). These rubber components may be used alone or in a blend of two or more. That is, it is preferable to mix at least one selected from natural rubber, isoprene rubber, styrene-butadiene copolymer rubber and polybutadiene rubber as the rubber component. The rubber component is a styrene-butadiene copolymer rubber alone, a mixture of styrene-butadiene copolymer rubber and polybutadiene rubber, a mixture of natural rubber and styrene-butadiene copolymer rubber, or a mixture of natural rubber and polybutadiene rubber. More preferably.
The rubber composition used for the tread portion preferably contains 50 to 100% by mass of SBR in the rubber component (that is, it is mainly SBR), and further contains 70 to 100% by mass of SBR. preferable. Moreover, it is preferable that the rubber composition used for the sidewall portion is a mixture of natural rubber and BR.

The nonionic surfactant represented by the above formula (I) used in the rubber composition of the present invention may be used alone or in combination of two or more.
R in the above formula (I) represents an alkyl group or alkenyl group having 1 to 21 carbon atoms, and the alkyl group and the alkenyl group may be linear, branched, or cyclic. These alkyl groups and alkenyl groups preferably have 5 to 21 carbon atoms, more preferably 7 to 17 carbon atoms, and still more preferably 7 to 13 carbon atoms.
N of the said Formula (I) is 10-24, Preferably it is 10-22, More preferably, it is 13-22.

The nonionic surfactant preferably has an HLB value (balance between hydrophilicity and lipophilicity) of 10 to 19. Here, in the present invention, the HLB value is defined by the Griffin equation shown below.
HLB = 20 × Mw / M
(In the formula, M is the molecular weight of the nonionic surfactant, and Mw is the molecular weight of the hydrophilic portion of the nonionic surfactant.)

If the nonionic surfactant has an HLB value of 10 or more, the lipophilicity will not be too strong, and the compatibility with rubber will not be too high, so it will easily migrate to the surface. On the other hand, if it is 19 or less, the hydrophilicity will not be too strong and the compatibility with the rubber will not be deteriorated, so that it becomes easy to knead and it is possible to suppress the adsorption to the filler and the difficulty of shifting to the surface. Further, the workability is improved by suppressing the decrease in adhesive strength without shortening the scorch time of the rubber composition.
The HLB value of the nonionic surfactant is more preferably 11-17. If the HLB value is 11 or more, the transition speed to the surface is increased and the effect of preventing browning is increased.

  As the nonionic surfactant represented by the above formula (I) used in the rubber composition of the present invention, a commercially available product can be suitably used. In particular, a polyoxyethylene fatty acid ester type nonionic surfactant manufactured by Kao Corporation and trade name “Emanon” (registered trademark) series are preferably mentioned.

The rubber composition preferably contains a wax and / or an anti-aging agent in order to suppress the occurrence and progression of cracks due to ozone. Here, examples of the wax include various microcrystalline waxes and paraffin waxes. As the microcrystalline wax, a product name “Ozoace” series manufactured by Nippon Seiwa Co., Ltd., a product name “Suntite” series manufactured by Seiko Chemical Co., Ltd. and the like can be suitably used. As the anti-aging agent, an amine-based anti-aging agent is preferable. For example, N- (1,3-dimethylbutyl) -N′-phenyl-p-phenylenediamine (6PPD), N-isopropyl-N′-phenyl-p -Phenylenediamine (IPPD), N, N'-diphenyl-p-phenylenediamine (DPPD) and the like.
It is preferable to mix 1.6 parts by mass or more of wax with respect to 100 parts by mass of the rubber component, more preferably 1.6 to 20 parts by mass, and still more preferably 2 to 10 parts by mass. Moreover, it is preferable to mix | blend 1.1 mass parts or more of anti-aging agents with respect to 100 mass parts of said rubber components, It is more preferable to mix | blend 1.1-15 mass parts, 1.5-10 mass parts combination More preferably.

  Moreover, carbon black and silica can be mix | blended with the said rubber composition as a reinforcing filler. Carbon black is not particularly limited, and any commercially available silica can be used. Among these, wet silica, dry silica, and colloidal silica are preferably used, and wet silica is particularly preferably used. Carbon black and silica may be used in combination, and the amount of these reinforcing fillers is preferably 10 to 150 parts by mass with respect to 100 parts by mass of the rubber component. In particular, from the viewpoint of exhibiting the effect of preventing discoloration of the present invention, 10 to 150 parts by mass of silica is blended with respect to 100 parts by mass of the rubber component, and the silane coupling agent is in a mass ratio (silane coupling agent / silica). (2/100) to (20/100) is preferable. Moreover, it is more preferable to mix | blend (4/100)-(20/100) silane coupling agent by mass ratio (silane coupling agent / silica) from a viewpoint of reinforcement improvement, and mass ratio (from a heat generating viewpoint). (Silane coupling agent / silica) is more preferably used in the range of (5/100) to (20/100).

  The rubber composition further contains a compounding agent usually used in the rubber industry such as a vulcanizing agent, a vulcanization accelerator, a scorch preventing agent, a softening agent, zinc oxide and stearic acid, which does not impair the purpose of the present invention. It can select suitably and mix | blend within the range. As these compounding agents, commercially available products can be suitably used.

  In addition, the said rubber composition can be manufactured by knead | mixing a rubber component, the said nonionic surfactant, and the various compounding agents suitably selected as needed, heat-injecting, extrusion, etc.

  The pneumatic tire of the present invention is characterized in that the rubber composition of the present invention is applied to any of the rubber members of the tire, and is applied to the tire outer shell, preferably a tread portion, particularly a cap tread portion forming a tire tread portion. Those applied are preferred. Since the tire contains the nonionic surfactant, the amine anti-aging agent and the wax are prevented from being transferred to the tire surface and discolored, and the appearance is good for a long time. is there.

［式（Ｉ）において、Ｒは、炭素数１〜２１のアルキル基又はアルケニル基を表し、該アルキル基及び該アルケニル基は直鎖状、分枝鎖状及び環状のいずれでもよく、ｎは１０〜２４である。
変色防止方法に用いられるイオン系界面活性剤、ゴム組成物に関する記載は、前述のとおりである。尚、「配合する」とは、ゴム成分と上記非イオン系界面活性剤とを混合した後に少なくとも混練する工程を含むことが好ましい。 The method for preventing discoloration of the rubber composition of the present invention includes at least one rubber component selected from diene synthetic rubber and natural rubber, and at least one nonionic system selected from compounds represented by the following formula (I): A surfactant is blended.

[In Formula (I), R represents an alkyl group or an alkenyl group having 1 to 21 carbon atoms, and the alkyl group and the alkenyl group may be linear, branched or cyclic, and n is 10 ~ 24.
The description regarding the ionic surfactant used for the discoloration prevention method and the rubber composition is as described above. Note that “compounding” preferably includes a step of kneading at least after mixing the rubber component and the nonionic surfactant.

  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.

Synthesis example 1
In a 500 milliliter four-necked flask, 240.0 g of polyethylene glycol 600 (reagent: molecular weight 600) and 114.0 g of stearic acid (trade name “Lunac S-90V” manufactured by Kao Corporation), dibutyltin oxide (Catalyst) Reagent) 0.18 g was weighed, heated to 230 ° C. under nitrogen blowing, and the esterification reaction was continued until the acid value became 2.0 mgKOH / g or less. Thereafter, the liquid temperature was cooled to 60 to 70 ° C., 0.19 g of 85% phosphoric acid (reagent) was added, and stirring was continued for 30 minutes. Furthermore, 0.7 g of an adsorbent (manufactured by Kyowa Chemical Industry Co., Ltd., trade name “KYOWARD 600S”) was added, and stirring was continued at this temperature for 30 minutes. Thereafter, vacuum filtration was performed using a filter aid to obtain polyethylene glycol 600 monostearate.

Synthesis example 2
Polyethylene glycol 1000 (reagent: molecular weight 1000) 300.0 g and lauric acid (trade name “Lunac L-98”, trade name “Lunac L-98”) 60.0 g in a 500 ml four-necked flask, dibutyltin oxide (catalyst) Reagent) 0.18 g was weighed, and polyethylene glycol 1000 monolaurate was obtained under the same conditions as in Synthesis Example 1.

Synthesis example 3
In a 500 milliliter four-necked flask, 80.0 g of polyethylene glycol 200 (reagent: molecular weight 200) and 114.0 g of stearic acid (trade name “Lunac S-90V”, manufactured by Kao Corporation), dibutyltin oxide (catalyst) Reagent) 0.18 g was weighed out, and polyethylene glycol 200 monostearate was obtained under the same conditions as in Synthesis Example 1.

Synthesis example 4
In a 500 milliliter four-necked flask, 330.0 g of polyethylene glycol 1100 (reagent: molecular weight 1100) and 85.5 g of stearic acid (trade name “Lunac S-90V”, manufactured by Kao Corporation), dibutyltin oxide (catalyst) Reagent) 0.18 g was weighed, and polyethylene glycol 1100 monostearate was obtained under the same conditions as in Synthesis Example 1.

Examples 1-7 and Comparative Examples 1-8
A rubber composition containing a non-ionic surfactant having a compounding formulation shown in Table 1 (SBR as a rubber component, that is, SBR alone or SBR / NR = 80/20) and a compounding amount shown in Table 2 was prepared. And vulcanized at 160 ° C. for 14 minutes. The obtained vulcanized rubber was measured and evaluated for tensile stress at 300% elongation, ozone resistance, and discoloration degree by the following methods. The results are shown in Table 2.

(1) Tensile stress at 300% elongation Tensile stress at 300% elongation was measured as a representative index of rubber physical properties. Specifically, using a JIS No. 3 dumbbell-type test piece, the tensile stress at 300% elongation was measured at 23 ° C. according to JIS K 6251: 2004. A larger index value indicates a greater tensile stress at 300% elongation.

(2) Ozone resistance According to JIS K 6259: 2004, an ozone deterioration test was performed on the test pieces prepared in Examples 1 to 7 and Comparative Examples 1 to 8 under the conditions of a temperature of 40 ° C., an ozone concentration of 50 pphm, and an elongation of 20%. After 50 hours, the test piece was observed for deterioration and evaluated for the presence or absence of cracks.

(3) Discoloration degree The discoloration degree of the vulcanized rubber test piece was evaluated using a chromaticity meter (manufactured by Nippon Denshoku Industries Co., Ltd., model name “NF333”). The colorimetric data was expressed as b * values. The b * value indicates the color. The b * value is 0 for colorless, positive for yellow and negative for blue. Regarding the degree of discoloration, after leaving the vulcanized rubber piece for one month under the environmental conditions of leaving it outdoors in the summer (directly exposed to sunlight for a specific time of the day under the roof where rain does not hit: Kodaira City) The degree of discoloration after standing was evaluated based on the b * value and the degree of visual discoloration.
The degree of discoloration is evaluated on a five-point scale, where 5 is the case where discoloration is severely recognized, 4 is the case where discoloration is observed in more than half of the whole, and 3 is the case where discoloration is observed in less than half of the whole. Is 2 and 1 is the case where no discoloration is observed.

* 1 Emulsion polymerization SBR, manufactured by JSR Corporation, trade name “SBR # 1500”
* 2 Carbon black N234, manufactured by Tokai Carbon Co., Ltd., trade name “SEAST 7HM”
* 3 Product name “Nipseal AQ” manufactured by Tosoh Silica Co., Ltd.
* 4 Bis (3-ethoxysilylpropyl) tetrasulfide, manufactured by Evonik Industries AG, trade name “Si69” (registered trademark)
* 5 Microcrystalline wax, manufactured by Nippon Seiwa Co., Ltd., trade name “Ozoace-0701”
* 6 N- (1,3-dimethylbutyl) -N′-phenyl-p-phenylenediamine (6PPD), manufactured by Ouchi Shinsei Chemical Co., Ltd., trade name “NOCRACK 6C”
* 7 2,2,4-Trimethyl-1,2-dihydroquinoline polymer, manufactured by Seiko Chemical Co., Ltd., trade name “Nonflex RD-S”
* 8 1,3-diphenylguanidine, manufactured by Ouchi Shinsei Chemical Co., Ltd., trade name “Noxeller D”
* 9 Di-2-benzothiazolyl disulfide, manufactured by Ouchi Shinsei Chemical Co., Ltd., trade name “Noxeller DM”
* 10 N-cyclohexyl-2-benzothiazolylsulfenamide, manufactured by Sanshin Chemical Industry Co., Ltd., trade name "Sunseller CM-G"

In Table 2, compound A is a nonionic surfactant manufactured by Kao Corporation, trademark “Emanon 1112” (polyethylene glycol monolaurate), and in the above formula (I), R is C ₁₁ H ₂₃ , a compound having n of 12 and HLB value of 13.7;
Compound B is a nonionic surfactant manufactured by Kao Corporation, trademark “Emanon 4110” (polyethylene glycol monooleate), wherein R is C ₁₇ H ₃₃ , n is 10 and HLB A compound having a value of 11.6;
Compound C is the polyethylene glycol 600 monostearate obtained in Synthesis Example 1, and in the above formula (I), R is C ₁₇ H ₃₅ , n is 13, and HLB value is 13.4. ;
Compound D is the polyethylene glycol 1000 monolaurate obtained in Synthesis Example 2, and in the above formula (I), R is C ₁₁ H ₂₃ , n is 22, and HLB value is 16.7. ;
Compound E is a nonionic surfactant manufactured by Kao Corporation, trademark “Emanon 3199V” (polyethylene glycol monostearate), wherein R is C ₁₇ H ₃₅ , n is 150, HLB A compound having a value of 19.4;
Compound F is the polyethylene glycol 200 monostearate obtained in Synthesis Example 3 above, and in the formula (I), R is C ₁₇ H ₃₅ , n is 4.5, and HLB value is 8.3. Is;
Compound G is a sorbitan nonionic surfactant manufactured by Kao Corporation, a trademark “Leodol TW-S106V” and an HLB value of 9.6;
Compound H is the polyethylene glycol 1100 monostearate obtained in Synthesis Example 4 above, and in the above formula (I), R is C ₁₇ H ₃₅ , n is 25, and the HLB value is 15.9. .
In addition, the unit of the compounding quantity of compound AH shown in Table 2 and Table 3 is a mass part with respect to 100 mass parts of rubber components.

From Table 2, the rubber compositions of Examples 1 to 7 using the compounds A to D are not discolored after a one-month outdoor standing test, have a good appearance, and have an elongation of 300%. Other physical properties were good in terms of tensile stress and ozone resistance.
On the other hand, the rubber compositions of Comparative Examples 1 to 3 that do not contain a nonionic surfactant, the compounds E and H having an n number that is too large, and the compound F that has an n number that is too small all have low effects of preventing discoloration. It was. In addition, Compound G, which aims to improve the appearance for sidewalls, had a low effect of preventing discoloration in the SBR single compounded rubber composition (compounds 1 and 2).

Example 8 and Comparative Example 9
Next, as shown in Table 3, as the tire tread rubber composition, the rubber composition of Example 8 containing Compound D and the rubber composition of Comparative Example 9 containing no surfactant were respectively tire size 195. The tire was applied to a tread part (cap tread part forming a tire tread part) of a / 65R15 passenger car radial tire, and each tire was manufactured by a conventional method, and the same discoloration test as described above was performed. The results are shown in Table 3.

  As shown in Table 3, it was found that the pneumatic tire of the present invention in which the rubber composition of the present invention was applied to the tread portion, particularly the cap tread portion forming the tire tread portion, had a high discoloration suppressing effect.

  The rubber composition of the present invention effectively prevents the amine-based anti-aging agent and wax from moving to the tire surface and discoloring when applied to the tire outer skin, particularly the tread portion. It becomes good over a long period of time. Therefore, the pneumatic tire of the present invention is suitably used as various pneumatic tires for passenger cars, light passenger cars, light trucks, small trucks, trucks / buses, construction vehicles, and the like.

Claims (14)

It is characterized by comprising at least one rubber component selected from diene-based synthetic rubber and natural rubber, and at least one nonionic surfactant selected from compounds represented by the following formula (I): A rubber composition.

[In Formula (I), R represents an alkyl group or an alkenyl group having 1 to 21 carbon atoms, and the alkyl group and the alkenyl group may be linear, branched or cyclic, and n is 10 ~ 24. ]   The rubber composition according to claim 1, wherein 0.1 to 10 parts by mass of the nonionic surfactant is blended with 100 parts by mass of the rubber component.   Furthermore, the rubber composition of Claim 1 or 2 formed by mix | blending a wax.   Furthermore, the rubber composition in any one of Claims 1-3 formed by mix | blending anti-aging agent.   The rubber composition according to claim 4, wherein the anti-aging agent is an amine-based anti-aging agent.   The rubber composition according to claim 3, wherein 1.6 parts by mass or more of the wax is blended with 100 parts by mass of the rubber component.   The rubber composition according to any one of claims 4 to 6, wherein 1.1 parts by mass or more of the anti-aging agent is blended with 100 parts by mass of the rubber component.   10 to 150 parts by mass of silica is blended with 100 parts by mass of the rubber component, and (2/100) to (20/100) of a silane coupling agent is further blended in a mass ratio (silane coupling agent / silica). The rubber composition according to any one of claims 1 to 7.   The rubber composition according to any one of claims 1 to 8, comprising at least one selected from natural rubber, isoprene rubber, styrene-butadiene copolymer rubber and polybutadiene rubber as the rubber component.   The rubber component is styrene-butadiene copolymer rubber alone, styrene-butadiene copolymer rubber and polybutadiene rubber, natural rubber and styrene-butadiene copolymer rubber, or natural rubber and polybutadiene rubber. A rubber composition according to any one of the above.   The rubber composition according to any one of claims 1 to 10, wherein 50 to 100% by mass of a styrene-butadiene copolymer rubber is blended in the rubber component.   The tire which applied the rubber composition in any one of Claims 1-11 to a tire outer skin.   The tire according to claim 12, wherein the tire skin is a tread portion. A rubber comprising at least one nonionic surfactant selected from a compound represented by the following formula (I) in at least one rubber component selected from diene-based synthetic rubber and natural rubber A method for preventing discoloration of a composition.

[In Formula (I), R represents an alkyl group or an alkenyl group having 1 to 21 carbon atoms, and the alkyl group and the alkenyl group may be linear, branched or cyclic, and n is 10 ~ 24. ]