JP2013147617A - Rubber composition and pneumatic tire using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a rubber composition that can strike a balance between grip performance at the time of drying and grip performance at the time of wetting, without especially decreasing abrasion resistance in a high level, and to provide a pneumatic tire using the same.SOLUTION: A rubber composition comprises combining, based on 100 pts.mass of at least one rubber component chosen from a natural rubber and a synthetic rubber: (A) 1-150 pts.mass of a softening agent that contains a polycyclic aromatic compound (PCA) in which the amount of the extract of dimethyl sulfoxide (DMSO) by an IP346 method is less than 3 mass%; (B) 5-100 pts.mass of a resin in which the softening point is 80-200°C; and (C) 20-300 pts.mass of silica and/or a compound shown by specific formula.

Description

  The present invention relates to a rubber composition and a pneumatic tire using the same, and in particular, a softening agent containing a polycyclic aromatic compound (PCA) component having a dimethyl sulfoxide (DMSO) extract amount of less than 3% by mass. The present invention relates to a rubber composition obtained by blending, and a pneumatic tire using the rubber composition.

  Conventionally, as a softener for rubber composition and a synthetic rubber extender oil, from the viewpoint of imparting high hysteresis loss characteristics and affinity with rubber, a highly aromatic oil produced using petroleum as a raw material is a rubber composition. It has been used favorably in objects and other areas.

  For example, for the purpose of improving dry grip performance and wet grip performance, Patent Document 1 describes a tire rubber composition containing a softening agent containing a terpene phenol resin and process oil.

International Publication No. 2009/125747

  Although these technologies can improve dry grip performance and wet grip performance, in recent years, not only dry grip performance and wet grip performance, but also higher levels of compatibility including wear resistance performance have been achieved. It was sought after.

  Also, a softening agent having a DMSO extract amount of less than 3% by mass, which is referred to as “Treated Distilled Aromatic Extracts (TDAE)” or “Mil Extracted Solvates (MES)” obtained by processing a highly aromatic oil produced from petroleum as a raw material. Further, by adding further silica or inorganic compound powder or applying a resin, the grip performance when dry and the grip performance when wet can be improved, respectively, but it is difficult to achieve both, especially in the former There was a risk that the wear resistance would be reduced.

  Accordingly, the present invention is to provide a rubber composition that can achieve both high-level grip performance when dry and grip performance when wet without particularly reducing wear resistance, and a pneumatic tire using the rubber composition. is there.

The rubber composition according to the present invention has a dimethyl sulfoxide (DMSO) extract amount of less than 3% by mass based on (A) IP346 method with respect to 100 parts by mass of at least one rubber component selected from natural rubber and synthetic rubber. 1 to 150 parts by mass of a softener containing a ring aromatic compound (PCA), (B) 5 to 100 parts by mass of a resin having a softening point of 80 to 200 ° C., (C) silica and / or the following general formula (I A rubber composition comprising 20 to 300 parts by mass of a compound represented by the formula:
M · xSiO ₂ · yH ₂ O (I)
(M in the formula (I) is at least one metal oxide or metal hydroxide selected from Al, Mg, Ti, and Ca, and x and y are each an integer of 0 to 10.)

  In such a rubber composition, more preferably, 20 to 200 parts by mass of the silica and 5 to 100 of the compound represented by the general formula (I) having a particle size of 10 μm or less with respect to 100 parts by mass of the rubber component. A mass part is mix | blended.

  Also preferably, the resin is a terpene-containing resin, preferably a terpene-phenol resin. The softening point of the resin is 140 to 200 ° C.

  Further, it is preferably at least one selected from light extraction solvate (MES), treated distillate aromatic distillate (TDAE), or heavy naphthenic oil.

And preferably, the softening agent further contains a naphthenic oil and / or a hydrogenated naphthenic oil, more preferably the hydrogenated naphthenic oil contains a naphthenic hydrocarbon measured in accordance with ASTM D2140. It is obtained by hydrogenating a naphthenic oil having an amount (% C _N ) of 30 or more.

Preferably, the softener further comprises asphalt having a kinematic viscosity at 120 ° C. of 300 mm ² / sec or less and 5% by mass or less of asphaltene as a mass ratio of naphthenic oil and / or hydrogenated naphthenic oil / asphalt. It contains in the range of / 5-5 / 95.

By the way, the rubber composition whose said general formula (I) is the following general formula (II) is preferable.
Al ₂ O ₃ .mSiO ₂ .nH ₂ O (II)
(M in the formula (II) is an integer of 1 to 4, and n is an integer of 0 to 4.)

  Moreover, the rubber composition whose compound represented with the said general formula (I) is aluminum hydroxide is preferable.

  Such a rubber composition can be applied to a pneumatic tire.

According to the present invention, storage elasticity is obtained by combining a predetermined softener, resin, and silica and / or a compound of the following general formula (I) and blending a resin having a high softening point and high compatibility with rubber. The rate decreases, the contact area with the road surface can be increased, and in particular, the grip performance when wet can be improved. As a result, the wet grip performance, the dry grip performance, and the slip between the tire and the road surface are reduced, so that the wear resistance can be provided at a high level.
In particular, the effect can be exhibited by applying it to a tread rubber of an ultra-high-performance passenger car or a pneumatic tire for racing that requires grip performance.

  The rubber composition of the present invention is a polycyclic ring having a dimethyl sulfoxide (DMSO) extract amount of less than 3% by mass based on (A) IP346 method with respect to 100 parts by mass of at least one rubber component selected from natural rubber and synthetic rubber. 1 to 150 parts by mass of a softener containing an aromatic compound (PCA), (B) 5 to 100 parts by mass of a resin having a softening point of 80 to 200 ° C., and (C) silica and / or the following general formula (I) 20 to 300 parts by mass of a compound represented by the formula is formulated.

  In the rubber composition of the present invention, natural rubber and synthetic rubber are used as the rubber component. Examples of the synthetic rubber include diene rubbers such as styrene-butadiene copolymer (SBR), polyisoprene (IR), polybutadiene (BR), solution-polymerized styrene-butadiene rubber, and emulsion-polymerized styrene-butadiene rubber. Among these, styrene-butadiene copolymer rubber produced by a solution polymerization method is preferable in consideration of the balance of various performances in the tire tread. These rubber components may be used alone or in combination of two or more.

The softening agent for component (A) includes an oil whose DMSO extract amount [PCA component (polycyclic aromatic compound)] according to the IP346 method is controlled to be less than 3% by mass, and is 1 to 150 parts per 100 parts by mass of the rubber component. It mix | blends by a mass part, Preferably it is 1-140 mass part, More preferably, it is 10-120 mass part.
Here, the IP346 method refers to a DMSO extract that is an aromatic compound content extracted with DMSO (dimethyl sulfoxide) in accordance with the regulations of the British Petroleum Institute.

  When the blending amount of the softening agent is less than 1 part by mass, the rubber is poorly dispersed and the rubber is cured and the grip performance when wet is deteriorated. On the other hand, when it exceeds 150 parts by mass, the rubber composition is softened to improve steering stability and resistance. Abrasion may be reduced.

  As the softening agent, a light extraction solvate (MES), a treated distillate aromatic extract (TDAE), heavy naphthenic oil, or the like is preferably used.

In this softener, it is preferable to blend naphthenic oil and / or hydrogenated naphthenic oil. This hydrogenated naphthenic oil can be obtained by hydrorefining a naphthenic oil in advance by a high-temperature high-pressure hydrorefining technique. The naphthenic oil to be hydrogenated preferably has a naphthenic hydrocarbon content (% C _N ) of 30 or more measured according to ASTM D2140.

  The amount of the hydrogenated naphthenic oil is preferably added in the range of 20 to 70% by mass with respect to the amount of oil whose DMSO extract amount is less than 3% by mass. Such hydrogenated naphthenic oils are specifically available as commercial products such as SNH8, SNH46, SNH220, SNH440 (all are trademarks) manufactured by Sankyo Oil Chemical Co., Ltd.

Furthermore, the softening agent can include asphalt. In consideration of compatibility with the synthetic rubber to be used and the effect as a softening agent, the asphalt preferably has an asphaltene component of 5% by mass or less. In addition, an asphaltene component is quantified from the composition analysis measured based on JPI method (Japan Petroleum Institute method). Such asphalt is particularly preferably naphthenic straight asphalt, and preferably has a kinematic viscosity at 120 ° C. of 300 mm ² / sec or less.

  The blending amount of the asphalt is preferably in the range of 95/5 to 5/95 as a blending mass ratio of hydrogenated naphthenic oil and asphalt. If the asphalt exceeds 95% by mass, there is a problem in compatibility with the synthetic rubber used, and the effect may be reduced.

  The asphalt mixing method is not particularly limited, and the asphalt is mixed with hydrogenated naphthenic oil in advance, or the main components of asphalt in the hydrogenated naphthenic oil are appropriately mixed in the conventional process of refining hydrogenated naphthenic oil. However, from the viewpoint of ease of preparation and economic efficiency of the softener, asphalt is dissolved in hydrogenated naphthenic oil (including extender oil and blended oil). The method of preparing is preferred.

  The resin of component (B) has a softening point of 80 to 200 ° C, preferably 140 to 200 ° C, and is 5 to 100 parts by weight, preferably 5 to 80 parts by weight, more preferably 100 parts by weight of the rubber component. Is 5-60 parts by mass.

Depending on the range of the softening point, both the loss characteristics and the rigidity can be balanced.
That is, if the temperature is less than 80 ° C., the desired effect of the present invention cannot be obtained. On the other hand, if the temperature exceeds 200 ° C., workability deterioration and grip shortage are caused by loss characteristics and rigidity more than necessary.

The loss characteristics and rigidity of the rubber composition can be ensured by the above composition range.
That is, if the blending amount is less than 5 parts by mass, the desired effect of the present invention cannot be obtained. On the other hand, if it exceeds 100 parts by mass, not only an effect commensurate with the increase is obtained, Loss characteristics are not obtained, and the grip performance when wet and the grip performance when dry tend to decrease rather than the tire performance.

  Moreover, about resin of the said (B) component, terpene containing resin is preferable and it is more preferable that it is a terpene phenol resin. This is because the loss characteristics and rigidity of the rubber composition can be balanced.

  The OH value of the terpene phenol resin is preferably 20 to 250, and particularly preferably 40 to 150. Within this range, the rubber composition for tires of the present invention can provide a performance balanced at a high level in both loss characteristics and rigidity.

  Since the above-mentioned terpene phenol resin can balance the loss characteristics and rigidity of the rubber composition in a well-balanced manner, both wet grip performance and dry grip performance can be achieved.

  The raw material terpene monomer of this terpene phenol resin is not limited, and is preferably a monoterpene hydrocarbon such as α-pinene or limonene, and α-pinene is used from the viewpoint of a balance between loss characteristics and rigidity. What is included is preferable, and α-pinene is particularly preferable.

  As the terpene phenol resin, for example, various grades of resin can be obtained under the trade names “YS Polystar” and “Mighty Ace G” manufactured by Yasuhara Chemical Co., Ltd. These terpene-containing resins may be used alone or in combination of two or more.

Component (C) is silica and / or the following general formula (I)
M · xSiO ₂ · yH ₂ O (I)
[M in the formula (I) is a metal oxide or metal hydroxide selected from Al, Mg, Ti and Ca, and x and y are each an integer of 0 to 10 which may be different. ]
These are inorganic compound powders represented by the following general formula (I): 20 to 300 parts by mass, preferably 20 to 200 parts by mass of silica, and 10 μm or less of the particle size with respect to 100 parts by mass of the rubber component. 5 to 100 parts by mass of a compound represented by

With the above composition range, it is possible to obtain a reinforcing filler and to maintain wear resistance and to obtain excellent grip performance when wet.
That is, if it is less than 20 parts by mass, the desired wet grip performance of the present invention cannot be obtained, while if it exceeds 300 parts by mass, the intended wear resistance cannot be obtained.

  (C) component silica does not represent only silicon dioxide in a narrow sense, but means a silicate-based filler. Specifically, in addition to anhydrous silicic acid, hydrous silicic acid, calcium silicate, silicic acid Includes silicates such as aluminum.

  Moreover, when using silica as (C) component, it is preferable to add a silane coupling agent at the time of mix | blending from a viewpoint of improving a reinforcement property and a dispersibility further. A silane coupling agent may be used individually by 1 type, and may be used together 2 or more types.

  When the x and y are both 0, the inorganic compound powder represented by the general formula (I) is at least one metal oxide or metal hydroxide selected from Al, Mg, Ti, and Ca. Become. Component (C) is at least one inorganic compound having an average particle size of 10 μm or less.

Specific examples of the inorganic compound represented by the general formula (I) include alumina (Al ₂ O ₃ ), magnesium hydroxide (Mg (OH) ₂ ), magnesium oxide (MgO), titanium white (TiO ₂ ), Examples thereof include titanium black (TiO _2n-1 ), talc (3MgO.4SiO ₂ .H ₂ O), and attapulgite (5MgO.8SiO ₂ .9H ₂ O). In addition, magnesium calcium silicate (CaMgSiO ₄ ) and magnesium silicate (MgSiO ₃ ) also exhibit the same effects as the inorganic compound.

The general formula (I) is preferably an inorganic compound represented by the following general formula (II) or aluminum hydroxide.
Al ₂ O ₃ .mSiO ₂ .nH ₂ O (II)
Here, m in the formula (II) is an integer of 1 to 4, and n is an integer of 0 to 4.

Specific examples of the inorganic compound represented by the general formula (II) include clay (Al ₂ O ₃ .2SiO ₂ ), kaolin (Al ₂ O ₃ .2SiO ₂ .2H ₂ O), pyrophyllite (Al ₂ O ₃ · 4SiO ₂ · H ₂ O), bentonite (Al ₂ O ₃ · 4SiO ₂ · 2H ₂ O), aluminum hydroxide [Al (OH) ₃ ], alumina (Al ₂ O ₃ ) and the like. (C) component which has the said characteristic used by this invention can be used individually or in mixture of 2 or more. Of these, aluminum hydroxide [Al (OH) ₃ ] is particularly preferable.

  In such a rubber composition, carbon black and / or silica can be used. The total amount of carbon black and silica is preferably 50 to 300 parts by mass, more preferably 70 to 250 parts by mass, and particularly preferably 80 to 220 parts by mass with respect to 100 parts by mass of the rubber component. In particular, when emphasis is placed on grip performance when wet, it is preferable to increase the blending ratio of silica.

  Examples of the carbon black include FEF, SRF, HAF, ISAF, and SAF. Among these, HAF, ISAF, and SAF that are particularly excellent in wear resistance are preferable.

  In addition, the above rubber composition includes various compounding agents usually used in the rubber industry, for example, a vulcanizing agent, a vulcanization accelerator, an anti-aging agent, a scorch, if desired, within a range that does not impair the object of the present invention. Inhibitors, softeners, zinc white, stearic acid and the like can be included. These may be used individually by 1 type and may use 2 or more types together.

Such a rubber composition is suitably used for tire tread rubber and base rubber. In addition, this tire is manufactured by a normal method. That is, if necessary, the tire rubber composition of the present invention containing various chemicals as described above is extruded into a tread member at an unvulcanized stage, and is subjected to a normal method on a tire molding machine. Paste molding is performed to form a green tire. The green tire is heated and pressed in a vulcanizer to obtain a tire.
As the gas filled in the tire, normal air or air with a changed oxygen partial pressure, or an inert gas such as nitrogen can be 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.

Based on each compounding prescription shown in Table 1, rubber compositions of Examples 1 to 4 and Comparative Examples 1 to 7 were produced by a conventional method. Next, wet grip performance, dry grip performance, and wear resistance performance were evaluated using the obtained rubber compositions.

１）ＪＳＲ（株）社製 １５００
２）東海カーボン（株）社製シースト７ＨＭ
３）東ソー・シリカ（株）社製ニップシールＡＱ
４）昭和電工製（株）社製商品名〔ハイジライトＨ−４３Ｍ〕
５）三共油化工業（株）社製ＳＮＨ２２０ ＤＭＳＯ抽出分量２．２％
６）ヤスハラケミカル（株）社製ＹＳポリスターＴ１６０、軟化点１６０℃、ＯＨ価７０（ｍｇＫＯＨ／ｇ）
７）信越化学工業（株）社製ＡＢＣ−８５６
８）大内新興化学工業（株）社製ノクラック６Ｃ
９）大内新興化学工業（株）社製ノクセラーＤＭ−Ｐ
１０）大内新興化学工業（株）社製ノクセラーＣＺ−Ｇ

1) 1500 manufactured by JSR Corporation
2) Seest 7HM manufactured by Tokai Carbon Co., Ltd.
3) NIPSEAL AQ manufactured by Tosoh Silica Corporation
4) Product name [Hijilite H-43M] manufactured by Showa Denko KK
5) Sankyo Oil Chemical Co., Ltd. SNH220 DMSO extract amount 2.2%
6) YS Polystar T160 manufactured by Yasuhara Chemical Co., Ltd., softening point 160 ° C., OH value 70 (mgKOH / g)
7) ABC-856 manufactured by Shin-Etsu Chemical Co., Ltd.
8) Nocrack 6C manufactured by Ouchi Shinsei Chemical Co., Ltd.
9) Noxeller DM-P manufactured by Ouchi Shinsei Chemical Industry Co., Ltd.
10) Noxeller CZ-G manufactured by Ouchi Shinsei Chemical Industry Co., Ltd.

(1) Grip performance when wet Using a British portable skid tester, the resistance value of the vulcanized rubber test piece against the wet concrete road surface was measured at room temperature, and the results are shown in Table 2.
In addition, it displays as an index | exponent by setting Comparative Example 1 to 100, and it shows that the grip performance in wetness is so favorable that a numerical value is large.

(2) Grip performance during drying Using a British portable skid tester, the resistance value of the vulcanized rubber test piece against the dry concrete road surface was measured at room temperature, and the results are shown in Table 2.
In addition, it displays as an index | exponent by setting Comparative Example 1 to 100, and it shows that the grip performance at the time of drying is so favorable that a numerical value is large.

(3) Wear resistance performance Using a Lambone-type wear tester, according to JIS K 6264, measure the wear amount at room temperature with a load of 1.5 kgf, a slip rate of 60%, and a measurement time of 60 seconds, and measure the reciprocal of the wear amount. The results are shown in Table 2.
In addition, it displays with an index | exponent by setting Comparative Example 1 to 100, and it shows that abrasion resistance is so favorable that a numerical value is large.

  From the results in Table 2, Examples 1 to 4 were able to improve wet grip performance and dry grip performance without degrading the wear resistance performance.

Claims (10)

For 100 parts by mass of at least one rubber component selected from natural rubber and synthetic rubber,
(A) 1 to 150 parts by mass of a softening agent containing a polycyclic aromatic compound (PCA) having a dimethyl sulfoxide (DMSO) extract amount of less than 3% by mass according to the IP346 method;
(B) 5-100 parts by mass of a resin having a softening point of 80-200 ° C.
(C) A rubber composition comprising 20 to 300 parts by mass of a compound represented by silica and / or the following general formula (I).
M · xSiO ₂ · yH ₂ O (I)
(M in the formula (I) is at least one metal oxide or metal hydroxide selected from Al, Mg, Ti, and Ca, and x and y are each an integer of 0 to 10.)   The compound according to claim 1, wherein 20 to 200 parts by mass of the silica and 5 to 100 parts by mass of the compound represented by the general formula (I) having a particle size of 10 μm or less are blended with 100 parts by mass of the rubber component. The rubber composition as described.   The rubber composition according to claim 1 or 2, wherein the resin is a terpene-containing resin.   The rubber composition according to claim 1, wherein the resin is a terpene-phenol resin.   The softening agent is at least one selected from light extraction solvate (MES), treated distillate aromatic distillate (TDAE), or heavy naphthenic oil. The rubber composition as described.   The rubber composition according to any one of claims 1 to 5, wherein the softening agent further contains a naphthenic oil and / or a hydrogenated naphthenic oil. The hydrogenated naphthenic oil is obtained by hydrogenating a naphthenic oil having a naphthenic hydrocarbon content (% C _N ) of 30 or more measured according to ASTM D2140. 6. The rubber composition according to 6. The softener further comprises an asphalt having a kinematic viscosity at 120 ° C. of 300 mm ² / sec or less and an asphaltene of 5% by mass or less as a mass ratio of naphthenic oil and / or hydrogenated naphthenic oil / asphalt. The rubber composition according to any one of claims 1 to 7, which is contained in a range of 5/95. The rubber composition according to any one of claims 1 to 8, wherein the general formula (I) is the following general formula (II).
Al ₂ O ₃ .mSiO ₂ .nH ₂ O (II)
(M in the formula (II) is an integer of 1 to 4, and n is an integer of 0 to 4.)   The rubber composition according to any one of claims 1 to 9, wherein the compound represented by the general formula (I) is aluminum hydroxide.