JP4447699B2 - Rubber composition - Google Patents

Description

【００２８】
表１に示す化合物のうち（１）〜（４）は以下の方法で合成した。
化合物（１）の合成
オレイルアルコールＣＨ₃（ＣＨ₂）₇ＣＨ＝ＣＨ（ＣＨ₂）₈ＯＨを４０３ｇ、水酸化カリウム０．４５ｇを容量１Ｌのオートクレーブに仕込み、空間部をチッ素で置換した。１１０℃に加温したあと、撹拌しながらエチレンオキサイド５７３ｇを徐々に圧入して反応させた。２時間後に内容物を取り出し、ケイ酸マグネシウム８ｇを加えて減圧下に撹拌しつつ１００℃で３０分間処理したあとろ過し、得られたろ液に酸化アルミニウム４ｇを加え、前記と同様の条件下にて処理したあとろ過し、ろ液として化合物（１）に対応する精製ポリエチレングリコールモノオレイルエーテル９２７ｇを得た。
【００２９】
化合物（２）の合成
アリルアルコールＣＨ₂＝ＣＨＣＨ₂ＯＨを８０ｇ、水酸化カリウム０．４５ｇを容量１Ｌのオートクレーブに仕込み、空間部をチッ素で置換した。１１０℃に加温したあと、撹拌しながらエチレンオキサイド５１６ｇを徐々に圧入して反応させた。２時間後に内容物を取り出し、ケイ酸マグネシウム８ｇを加えて減圧下に撹拌しつつ１００℃で３０分間処理したあとろ過し、得られたろ液に酸化アルミニウム４ｇを加え、前記と同様の条件下にて処理したあとろ過し、ろ液として化合物（２）に対応する精製ポリエチレングリコールモノアリルエーテル５６６ｇを得た。
【００３０】
化合物（３）の合成
アリルアルコールＣＨ₂＝ＣＨＣＨ₂ＯＨを７８．４ｇ、水酸化カリウム０．４５ｇを容量１Ｌのオートクレーブに仕込み、空間部をチッ素で置換した。１１０℃に加温したあと、撹拌しながらエチレンオキサイド７１４ｇを徐々に圧入して反応させた。２時間後に内容物を取り出し、ケイ酸マグネシウム８ｇを加えて減圧下に撹拌しつつ１００℃で３０分間処理したあとろ過し、得られたろ液に酸化アルミニウム４ｇを加え、前記と同様の条件下にて処理したあとろ過し、ろ液として化合物（３）に対応する精製ポリエチレングリコールモノアリルエーテル７５２ｇを得た。
【００３１】
化合物（４）の合成
ポリエチレングリコール（ＰＥＧ４００）１００ｇと水酸化ナトリウムを水３３ｇ当たり２２ｇ、ＴＨＦ５００ｍｌを１Ｌのセパラブルフラスコに入れ、７０℃で５時間撹拌し、４０℃まで降温後、アリルクロリド４２．０９ｇを滴下し、４０℃で一晩（２０時間）反応させた。反応終了後、ガラスフィルターでろ過し、ろ液を濃縮して１Ｌの分液ロートに入れ、水を加え、塩酸で中和した。ついで、エーテルで抽出し、エーテル層を濃縮して化合物（４）を得た。
【００３２】
実施例１〜４および比較例１〜３
得られた化合物（１）〜（４）ならびに既存の化合物（５）（三洋化成工業（株）製）および化合物（６）（三洋化成工業（株）製）を表２に示す配合処方に従い、加硫剤以外の薬品を１．７リットルＢＲ型バンバリーミキサー（（株）神戸製鋼所製）で混練り配合し、各種供試ゴム組成物を得た。これらの配合物に加硫剤を添加し６インチロール（関西ロール社製）にて１７０℃で２０分間プレス加硫して加硫物を得、これらについて前記特性試験を行った。結果を表３に示す。
【００３３】
【表２】

【００３４】
【表３】

【００３５】
【発明の効果】
本発明により、加工性、耐磨耗性および導電性を低下させることなく、転がり抵抗特性およびウェットグリップ性能を高めるタイヤ用のゴム組成物が得られる。
【図面の簡単な説明】
【図１】実施例１〜４および比較例１〜３で導電性の評価に用いるゴム試験片の説明図である。
【符号の説明】
１ ゴム試験片
２ 電極
ａ ゴム試験片の厚さ
ｂ ゴム試験片の幅
Ｌ 電極間の距離
Ａ ゴム試験片の総長[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a rubber composition for a tire that improves wet grip performance while maintaining low heat build-up (rolling resistance characteristics) without reducing workability, wear resistance, and conductivity.
[0002]
[Prior art]
In recent years, the characteristics required for automobile tires are diverse, such as low fuel consumption, steering stability, wear resistance, and ride comfort, and various devices have been devised to improve these performances. Among these performances, tire grip performance and rolling resistance characteristics are particularly related to rubber hysteresis loss. In general, increasing the hysteresis loss increases the gripping force and improves the braking performance, but also increases the rolling resistance, resulting in an increase in fuel consumption. As described above, since grip performance and rolling resistance characteristics are in a contradictory relationship, various rubber compositions for tires have been proposed to satisfy both characteristics simultaneously. For example, in a rubber composition for tires, since both polymer and carbon black have a great influence on both properties, when a styrene-butadiene copolymer is used as the polymer, the content of bound styrene, butadiene portion 1, The two bond content is appropriately selected to improve both rolling resistance characteristics and grip performance. On the other hand, with regard to carbon black, if the particle size is increased or the blending amount is decreased, the anti-cut chipping performance is lowered. It is effective.
[0003]
In recent years, a method of using a white filler such as silica as a low heat generation filler is known.
[0004]
However, when a white filler such as silica is used, the conductivity due to carbon black is impaired, resulting in a decrease in chargeability. In order to solve these problems, WO95 / 31888 shows that the volume resistance of a rubber composition is reduced by compounding a nonionic surfactant or a phosphate ester. JP-A-10-330539 discloses that antistatic performance can be maintained for a long time by adding a polyoxyalkylene glycol compound to a rubber composition using a white filler such as silica. However, although this patent shows that polyoxyalkylene glycol has antistatic performance, there is no description or suggestion about low heat build-up (rolling resistance characteristics) and wet grip performance. The idea is different. Note that “low heat generation” and “rolling resistance characteristics” are common in that both are phenomena caused by the energy loss component (tan δ) of rubber, and can be treated synonymously.
[0005]
[Problems to be solved by the invention]
Provided is a rubber composition for a tire that contains a white filler such as silica and that satisfies rolling resistance characteristics and wet grip performance without lowering processability, wear resistance, and conductivity.
[0006]
[Means for Solving the Problems]
As a result of intensive studies to solve the above-mentioned problems, the present inventors have found a method for satisfying rolling resistance characteristics and wet grip performance without reducing workability, wear resistance and conductivity, and completing the present invention. I went to.
[0007]
That is, the invention according to claim 1 is directed to natural rubber and / or diene-based synthetic rubber with a white filler as a filler and a general formula (I) R ¹ O (R ² O) _n R ³ (formula ( In I), R ¹ and R ³ are a hydrogen atom, a linear or branched saturated or unsaturated aliphatic hydrocarbon group having 1 to 22 carbon atoms, or an aryl group, and may be the same or different from each other Provided that R ¹ and R ³ are both hydrogen atoms, and R ² is a methylene group, an ethylene group, a propylene group, or a tetramethylene group, and they are all the same or different. N is an integer of 1 or more and 100 or less.) A rubber composition comprising a polyoxyalkylene glycol compound represented by the formula:
[0008]
Invention according to claim 2, wherein R ¹ is a hydrogen atom of a polyoxyalkylene glycol compound represented by the general formula (I), R ³ is a straight-chain or branched unsaturated aliphatic having 1 to 22 carbon atoms The rubber composition according to claim 1, which is a hydrocarbon group or an aryl group.
[0009]
In the invention according to claim 3, in the polyoxyalkylene glycol compound represented by the general formula (I), R ¹ is a hydrogen atom, and R ³ is a vinyl group, an allyl group, an isopropenyl group, or a 2-methylallyl group. The rubber composition according to claim 1, which is any one of the following.
[0010]
DETAILED DESCRIPTION OF THE INVENTION
The rubber component used in the present invention is natural rubber (NR) and / or a diene synthetic rubber. Examples of the diene-based synthetic rubber used in the present invention include styrene-butadiene rubber (SBR), polybutadiene rubber (BR), polyisoprene rubber (IR), ethylene-propylene-diene rubber (EPDM), chloroprene rubber (CR), and acrylonitrile-butadiene. Examples thereof include rubber (NBR), and the rubber component used in the present invention may be contained in one kind or two or more kinds.
[0011]
Next, examples of the white filler used in the rubber composition of the present invention include silica, clay, alumina, talc, calcium carbonate, magnesium carbonate, aluminum hydroxide, magnesium hydroxide, magnesium oxide, and titanium oxide. Or it can use in mixture of 2 or more types. Particularly preferred white fillers include silica, clay, aluminum hydroxide, and alumina. The amount of the white filler contained in the rubber composition of the present invention is preferably 5 to 100 parts by weight, more preferably 10 to 85 parts by weight, particularly 100 parts by weight of the rubber used in the present invention. Preferably it is 20-65 weight part. If the amount of the white filler is less than 5 parts by weight, the reinforcing effect is small. From the viewpoint of low heat build-up and workability, the amount of white filler is particularly preferably 20 to 65 parts by weight. When using a white filler, a coupling agent may be used in order to strengthen the bond between the filler and the rubber component and improve the wear resistance.
[0012]
As the coupling agent used in the rubber composition of the present invention, a silane coupling agent is preferably used. Specifically, for example, bis (3-triethoxysilylpropyl) tetrasulfide, bis (2-triethoxysilylethyl) tetrasulfide, bis (3-trimethoxysilylpropyl) tetrasulfide, bis (2-trimethoxysilyl) Ethyl) tetrasulfide, 3-mercaptopropyltrimethoxysilane, 3-mercaptopropyltriethoxysilane, 2-mercaptoethyltrimethoxysilane, 2-mercaptoethyltriethoxysilane, 3-nitropropyltrimethoxysilane, 3-nitropropyltri Ethoxysilane, 3-chloropropyltrimethoxysilane, 3-chloropropyltriethoxysilane, 2-chloroethyltrimethoxysilane, 2-chloroethyltriethoxysilane, 3-trimethoxysilylpropyl-N, -Dimethylthiocarbamoyl tetrasulfide, 3-triethoxysilylpropyl-N, N-dimethylthiocarbamoyl tetrasulfide, 2-triethoxysilylethyl-N, N-dimethylthiocarbamoyl tetrasulfide, 3-trimethoxysilylpropylbenzothiazole tetra Sulfide, 3-triethoxysilylpropyl benzothiazole tetrasulfide, 3-triethoxysilylpropyl methacrylate monosulfide, 3-trimethoxysilylpropyl methacrylate monosulfide, and the like, and bis (3 -Triethoxysilylpropyl) tetrasulfide is preferred. The amount of the silane coupling agent is preferably 1 to 20% by weight based on the weight of the white filler. If the amount of the silane coupling agent is less than 1% by weight, the effect of adding the silane coupling agent is not sufficient. If the amount exceeds 20% by weight, the coupling effect cannot be obtained at the cost of increasing the reinforcement and wear resistance. This is not preferable because the properties are lowered. From the viewpoint of the dispersion effect and the coupling effect, the blending amount of the silane coupling agent is desirably 2 to 15% by weight.
[0013]
In the rubber composition of the present invention, carbon black or the like can be used in combination as a filler in addition to the white filler. The amount of carbon black contained in the rubber composition of the present invention is preferably 80 parts by weight or less with respect to 100 parts by weight of the rubber component. If the blending amount of carbon black exceeds 80 parts by weight, the heat build-up increases, which is not preferable. From the viewpoint of reinforcement and low heat build-up, 25 to 60 parts by weight is more preferable.
[0014]
Examples of carbon black that can be used in the present invention include HAF, ISAF, and SAF, but are not particularly limited.
[0015]
The polyoxyalkylene glycol compound used in the present invention is a polyoxyalkylene glycol compound represented by the following general formula (I).
[0016]
R ¹ O (R ² O) _n R ³ (I)
(In the formula (I), R ¹ and R ³ are a hydrogen atom, a linear or branched saturated or unsaturated aliphatic hydrocarbon group having 1 to 22 carbon atoms, or an aryl group, and are the same as each other. Provided that R ¹ and R ³ are both hydrogen atoms, and R ² is a methylene group, an ethylene group, a propylene group, or a tetramethylene group, all of which are the same. And n is an integer of 1 to 100.)
In the polyoxyalkylene glycol compound represented by the general formula (I), R ¹ is a hydrogen atom, and R ³ is a linear or branched unsaturated aliphatic hydrocarbon group having 1 to 22 carbon atoms or an aryl group. More preferably, R ¹ is a hydrogen atom, and R ³ is more preferably a vinyl group, an allyl group, an isopropenyl group, or a 2-methylallyl group.
[0017]
The compounding amount of the polyoxyalkylene glycol compound contained in the rubber composition of the present invention is preferably 1 to 15% by weight, more preferably 2 to 12% by weight, based on the amount of the white filler. When the blending amount of the polyoxyalkylene glycol compound is less than 1% by weight, the wet grip performance is not sufficient, and when it exceeds 15% by weight, the performance cannot be obtained although the cost is increased.
[0018]
The rubber composition of the present invention includes the rubber component, a white filler as a filler, a coupling agent, and a polyoxyalkylene glycol compound, if necessary, a softener, an anti-aging agent, a vulcanizing agent, A compounding agent used in a normal rubber industry such as a vulcanization accelerator and a vulcanization accelerator auxiliary can be appropriately mixed.
[0019]
【Example】
EXAMPLES Hereinafter, although this invention is demonstrated concretely based on an Example, this invention is not limited to these.
[0020]
The reagents used are summarized below.
Diene-based synthetic rubber: SBR1502 manufactured by JSR Corporation
(Styrene-butadiene copolymer)
Silica: Ultrasil VN3 manufactured by Degussa
(Nitrogen adsorption specific surface area: 210 m ² / g)
Silane coupling agent: Si69 manufactured by Degussa
(Bis (3-triethoxysilylpropyl) tetrasulfide)
Anti-aging agent: NOCRACK 6C manufactured by Ouchi Shinsei Chemical Co., Ltd.
(N- (1,3-dimethylbutyl) -N′-phenyl-p-phenylenediamine)
Stearic acid: Zinc stearate manufactured by Nippon Oil & Fats Co., Ltd .: Zinc Hua No. 1 manufactured by Mitsui Mining & Smelting Co., Ltd. Sulfur: Powdered sulfur vulcanization accelerator manufactured by Tsurumi Chemical Co., Ltd. Noxeller NS made by
(Nt-butyl-2-benzothiazylsulfenamide)
Vulcanization accelerator DPG: Noxeller D manufactured by Ouchi Shinsei Chemical Industry Co., Ltd.
(N, N'-diphenylguanidine)
[0021]
The test methods carried out are summarized below.
Workability Measured at 130 ° C. according to the Mooney viscosity measurement method defined in JIS K6300. The Mooney viscosity ML (1 + 4) of Comparative Example 1 was set to 100, and indexed by the following calculation formula. The larger the value, the lower the Mooney viscosity and the better the processability.
Mooney viscosity index = ML (1 + 4) of Comparative Example 1 / ML (1 + 4) × 100 of each formulation
[0022]
Abrasion test A wear test was performed using a Lambourne abrasion tester. At that time, the measurement conditions were a temperature of 20 ° C., a slip rate of 20%, and a test time of 5 minutes. The volume loss of each formulation was calculated, and the loss amount of Comparative Example 1 was taken as 100, and the index was expressed by the following calculation formula. The higher the value, the better the wear resistance.
Abrasion index = loss amount of Comparative Example 1 / loss amount of each formulation × 100
[0023]
Viscoelasticity test A viscoelasticity test was performed using a viscoelasticity spectrometer VES (manufactured by Iwamoto Seisakusho), and tan δ was measured. At that time, the measurement conditions were a temperature of 70 ° C., an initial strain of 10%, and a dynamic strain of 2%.
[0024]
The tan δ of each rolling resistance characteristic blend was measured by the viscoelasticity test, and the tan δ of Comparative Example 1 was set to 100, and the index was expressed by the following formula. The higher the value, the better the rolling resistance characteristics.
Rolling resistance characteristic index = tan δ of Comparative Example 1 / tan δ of each formulation × 100
[0025]
Wet skid test Measured according to the method of ASTM E 303-83 using a portable skid tester manufactured by Stanley Co., Ltd., and indicated by the following formula. The larger the value, the better the wet skid performance.
Wet skid performance index = Numerical value of each formulation / Numerical value of Comparative Example 1 × 100
[0026]
A vulcanized rubber sheet obtained by vulcanization at 170 ° C. for 20 minutes was cut in a direction parallel to the roll axis, and a rubber test piece (a = 1 mm, b = 20 mm, L = 70 mm) as shown in FIG. And A ≧ 100 mm). Here, 1 is a rubber test piece, 2 is an electrode, a is the thickness of the rubber test piece, b is the width of the rubber test piece, L is the distance between the electrodes, and A is the total length of the rubber test piece. The electrode 2 was produced by applying an electrically conductive paste at a predetermined interval after applying an insulating tape to the surface of the rubber test piece 1. After the obtained test piece was held at 23 ± 2 ° C. for 48 hours, the resistance value R between the electrodes was measured at the same temperature, and the volume specific resistance value (Rv) was calculated as Rv = (a × b × R) / L It was calculated from the formula of and was expressed as an index using the following formula. The larger the value, the better the conductivity, and the better the static electricity is not generated.
Conductivity index = Rv of Comparative Example 1 / Rv of each formulation × 100
Table 1 shows the polyoxyalkylene glycol compounds used for the evaluation.
[0027]
[Table 1]

[0028]
Among the compounds shown in Table 1, (1) to (4) were synthesized by the following method.
Synthesis of Compound (1) 403 g of oleyl alcohol CH ₃ (CH ₂ ) ₇ CH═CH (CH ₂ ) ₈ OH and 0.45 g of potassium hydroxide were charged into a 1 L capacity autoclave, and the space was replaced with nitrogen. After heating to 110 ° C., 573 g of ethylene oxide was gradually injected while being stirred to react. After 2 hours, the contents were taken out, 8 g of magnesium silicate was added, and the mixture was treated at 100 ° C. for 30 minutes with stirring under reduced pressure. After filtration, 4 g of aluminum oxide was added to the obtained filtrate, and the conditions were the same as above. And then filtered to obtain 927 g of purified polyethylene glycol monooleyl ether corresponding to the compound (1) as a filtrate.
[0029]
Synthesis of Compound (2) 80 g of allyl alcohol CH ₂ ═CHCH ₂ OH and 0.45 g of potassium hydroxide were charged into a 1 L capacity autoclave, and the space was replaced with nitrogen. After heating to 110 ° C., 516 g of ethylene oxide was gradually injected and reacted with stirring. After 2 hours, the contents were taken out, 8 g of magnesium silicate was added, and the mixture was treated at 100 ° C. for 30 minutes with stirring under reduced pressure. After filtration, 4 g of aluminum oxide was added to the obtained filtrate, and the same conditions as described above were applied. After the treatment, filtration was performed to obtain 566 g of purified polyethylene glycol monoallyl ether corresponding to the compound (2) as a filtrate.
[0030]
Synthesis of Compound (3) 78.4 g of allyl alcohol CH ₂ ═CHCH ₂ OH and 0.45 g of potassium hydroxide were charged into an autoclave having a capacity of 1 L, and the space was replaced with nitrogen. After heating to 110 ° C., 714 g of ethylene oxide was gradually injected and reacted with stirring. After 2 hours, the contents were taken out, 8 g of magnesium silicate was added, and the mixture was treated at 100 ° C. for 30 minutes with stirring under reduced pressure. After filtration, 4 g of aluminum oxide was added to the obtained filtrate, and the same conditions as described above were applied. After the treatment, filtration was performed to obtain 752 g of purified polyethylene glycol monoallyl ether corresponding to the compound (3) as a filtrate.
[0031]
Synthesis of Compound (4) 100 g of polyethylene glycol (PEG400) and 22 g of sodium hydroxide per 33 g of water and 500 ml of THF were placed in a 1 L separable flask, stirred at 70 ° C. for 5 hours, cooled to 40 ° C., then allyl chloride 42. 09 g was added dropwise and reacted at 40 ° C. overnight (20 hours). After completion of the reaction, the mixture was filtered through a glass filter, the filtrate was concentrated, put into a 1 L separatory funnel, water was added, and the mixture was neutralized with hydrochloric acid. Subsequently, extraction with ether was performed, and the ether layer was concentrated to obtain a compound (4).
[0032]
Examples 1-4 and Comparative Examples 1-3
The obtained compounds (1) to (4) and the existing compound (5) (manufactured by Sanyo Chemical Industries, Ltd.) and compound (6) (manufactured by Sanyo Chemical Industries, Ltd.) according to the formulation shown in Table 2, Chemicals other than the vulcanizing agent were kneaded and blended with a 1.7 liter BR type Banbury mixer (manufactured by Kobe Steel, Ltd.) to obtain various test rubber compositions. A vulcanizing agent was added to these blends, and vulcanized products were obtained by press vulcanization at 170 ° C. for 20 minutes with a 6-inch roll (manufactured by Kansai Roll Co., Ltd.). The results are shown in Table 3.
[0033]
[Table 2]

[0034]
[Table 3]

[0035]
【The invention's effect】
According to the present invention, it is possible to obtain a rubber composition for a tire that improves rolling resistance characteristics and wet grip performance without reducing workability, wear resistance, and conductivity.
[Brief description of the drawings]
FIG. 1 is an explanatory diagram of rubber test pieces used for evaluation of conductivity in Examples 1 to 4 and Comparative Examples 1 to 3. FIG.
[Explanation of symbols]
1 Rubber test piece 2 Electrode a Rubber test piece thickness b Rubber test piece width L Distance between electrodes A Total length of rubber test piece

Claims (2)

5 to 100 parts by weight of a white filler as a filler with respect to 100 parts by weight of a rubber component that is a natural rubber and / or a diene synthetic rubber ,
R ¹ O (R ² O) _n R ³ (I)
(In the formula (I), R ¹ is a hydrogen atom, R ³ is any one of a vinyl group, an allyl group, an isopropenyl group, and a 2-methylallyl group. R ² is a methylene group, an ethylene group, propylene. Or a tetramethylene group, which may be the same or different, and n is an integer of 1 to 100.) The amount of the white filler 1 to 15% by weight of a rubber composition for tires, The rubber composition for tires according to claim 1, wherein a silane coupling agent is blended in an amount of 1 to 20% by weight based on the weight of the white filler.

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