JP2016003274A - Rubber composition and pneumatic tire using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a rubber composition and a pneumatic tire using the same which, in strongly desired development of a tire which has a low fuel consuming property while maintaining grip performance on dry and wet road surfaces, can solve problems that, when a resin is blended to improve such properties, tan δ (60°C) is worsened, and that, when silica is blended, workability and abrasion resistance are deteriorated.SOLUTION: There is provided a rubber composition formed by blending, relative to 100 pts.mass of a diene-based rubber, 1 to 30 pts.mass of a C-based petroleum resin modified with a phenolic compound, having a weight average molecular weight Mw of 200 to 1000 and a softening point in a range of -40 to 20°C and 80 to 200 pts.mass of silica.

Description

  The present invention relates to a rubber composition and a pneumatic tire using the same, and more specifically, a rubber composition capable of improving all of dry and wet grip performance, rolling resistance, workability and wear resistance, and the same. The present invention relates to a pneumatic tire using a tire.

  As the performance and functionality of automobiles increase, the required performance of tires has become higher year by year. For example, there is a strong demand for the development of tires that have low fuel consumption while maintaining grip performance on dry and wet road surfaces. A technique for blending a resin to improve these performances is known (see, for example, Patent Document 1). Such a resin has a tan δ profile independent of the rubber component, can improve the tan δ balance of the compound, and is blended mainly for improving wet grip performance. However, since the resin generally has a glass transition point higher than that of the rubber component, there is a problem that tan δ (60 ° C.) is deteriorated and low rolling performance cannot be obtained. In addition to this, a technique of blending a large amount of a filler having a small particle diameter in order to improve the grip performance is also known, but such a method also deteriorates rolling resistance.

  On the other hand, in order to improve rolling resistance, the technique which mix | blends a silica with a rubber composition is also known. However, silica has a tendency to agglomerate due to the formation of hydrogen bonds due to silanol groups present on the particle surface, and the rubber composition has a high Mooney viscosity at the time of kneading, which deteriorates processability and resistance. There was a problem that the wear resistance deteriorated.

Japanese Patent Laid-Open No. 4-300932

  Accordingly, an object of the present invention is to provide a rubber composition capable of improving all of dry and wet grip performance, rolling resistance, workability and wear resistance, and a pneumatic tire using the rubber composition.

The present inventors have results of extensive research with respect to the diene rubber, by blending with the phenolic compound modified with C ₉ petroleum resin and silica having specific properties in a specific amount, it solves the above problems The present invention was completed by finding out what can be done.
That is, the present invention is as follows.

1. To diene rubber 100 parts by weight, the weight average molecular weight Mw of 200 to 1000, and a softening point in the range of -40~20 ℃, 1~30 mass _{C 9} petroleum resins modified with phenolic compounds A rubber composition comprising 80 parts by weight and 200 parts by weight of silica.
2. Phenolic modified C ₉ petroleum resin compound, the rubber composition according to the 1, which is a modified C ₉ petroleum resin with phenol.
3. 3. The rubber composition as described in 1 or 2 above, wherein 1 to 30 parts by mass of an aromatic modified terpene resin is further blended with 100 parts by mass of the diene rubber.
4). A pneumatic tire using the rubber composition according to any one of 1 to 3 as a tread.

According to the present invention, to the diene rubber, since the compounded with a specific amount of the C ₉ petroleum resin and silica modified with phenolic compounds with specific properties, dry and wet grip performance, rolling resistance, processability It is possible to provide a rubber composition and a pneumatic tire using the rubber composition that can improve both the wear resistance and the wear resistance.

  Hereinafter, the present invention will be described in more detail.

(Diene rubber)
As the diene rubber used in the present invention, any diene rubber that can be blended in the rubber composition can be used, for example, natural rubber (NR), isoprene rubber (IR), butadiene rubber (BR). Styrene-butadiene copolymer rubber (SBR), acrylonitrile-butadiene copolymer rubber (NBR), ethylene-propylene-diene terpolymer (EPDM), and the like. These may be used alone or in combination of two or more. The molecular weight and microstructure are not particularly limited, and may be terminally modified with an amine, amide, silyl, alkoxysilyl, carboxyl, hydroxyl group or the like, or may be epoxidized.
Among these diene rubbers, SBR and NR are particularly preferable as the diene rubber from the viewpoint of the effect of the present invention. As the diene rubber, it is preferable to use a non-hydrogenated rubber.

(Modified C ₉ petroleum resin with a phenol compound)
_{C 9} petroleum resins modified with phenolic compounds used in the present invention has a weight average molecular weight Mw of 200 to 1000, and a softening point in the range of -40~20 ℃. Also, the C ₉ petroleum resin is a liquid at room temperature.
As is well known, the C ₉ petroleum resin is an aromatic petroleum resin obtained by (co) polymerizing a C ₉ fraction obtained by thermal decomposition of naphtha. Typical C ₉ petroleum resin, styrene, vinyl toluene, and a-methyl styrene, indene, one or more selected from methyl indene and dicyclopentadiene as monomer units.
C ₉ petroleum resins modified with phenolic compounds used in the present invention, for example, a C ₉ fraction can be obtained by cationic polymerization in the presence of phenolic compounds. Examples of the phenolic compound include phenol, cresol, xylenol, pt-butylphenol, p-octylphenol, p-nonylphenol, and the like. Among them, phenol is preferable from the viewpoint of improving the effect of the present invention.
Here, the weight average molecular weight Mw of C ₉ petroleum resins modified with phenolic compound is less than 200, and grip performance deteriorates, more than 1000 and low rolling resistance Conversely, processability, abrasion resistance Both get worse. When the softening point is less than −40 ° C., the wet grip performance is deteriorated.
The weight average molecular weight is measured by a GPC method in terms of polystyrene, and the softening point is measured by a ring and ball method defined in JIS K6220-1.
Incidentally, _{C 9} petroleum resins modified with phenolic compounds used in the present invention may be used those commercially available, for example, Rutgers Co. Nobaresu L100, Nobaresu L800, Nobaresu A1200, etc. Nobaresu LC60 is cited It is done.
By blending the modified C ₉ petroleum resin with a phenol-based compound, a silanol group of the OH groups and the silica of the resin to interact, increased dispersibility of the silica, it is presumed that the desired properties are expressed.

(silica)
As the silica used in the present invention, any silica conventionally known to be used in rubber compositions such as dry silica, wet silica, colloidal silica and precipitated silica is used alone or in combination of two or more. it can.
In the present invention, from the viewpoint of further improving the effect of the present invention, the BET specific surface area (measured in accordance with ISO 5794/1) of silica is preferably 100 to 400 m ² / g, and preferably 150 to 350 m. More preferably, it is ² / g.

(Rubber composition ratio)
The rubber composition of the present invention, to the diene rubber 100 parts by weight, characterized by comprising a modified C ₉ petroleum resin to 30 parts by weight and silica in the above phenolic compounds were blended 80 to 200 parts by weight And
When the blending amount of the C9 petroleum resin modified with the phenol compound is less than 1 part by mass, the blending amount is too small to achieve the effects of the present invention. Conversely, if it exceeds 30 parts by mass, the wear resistance performance deteriorates.
When the compounding amount of the silica is less than 80 parts by mass, the wet grip performance is deteriorated, and when it exceeds 200 parts by mass, the rolling resistance is deteriorated.
A more preferable blending amount of the C9 petroleum resin modified with the phenol compound is 5 to 20 parts by mass with respect to 100 parts by mass of the diene rubber.
A more preferable blending amount of the silica is 90 to 150 parts by mass with respect to 100 parts by mass of the diene rubber.
Here, from the viewpoint of further enhancing the effect of the present invention, the C9 petroleum resin modified with a phenolic compound is preferably blended in an amount of 1 to 30% by mass, and 3 to 25% by mass based on silica. Further preferred.

(Aromatic modified terpene resin)
Moreover, in this invention, it is preferable to mix | blend an aromatic modified terpene resin from a viewpoint of improving the effect of this invention including grip performance further.
Examples of the aromatic modified terpene resin are obtained by polymerizing terpene resins such as α-pinene, β-pinene, dipentene, and limonene and aromatic compounds such as styrene, α-methylstyrene, vinyltoluene, and indene. Aromatic modified terpene resins are used effectively. The content of the aromatic compound in the aromatic modified terpene resin is preferably 10 to 50% by mass. The softening point of the aromatic modified terpene resin is preferably 80 to 170 ° C.
In addition, the compounding quantity of aromatic modified terpene resin is 1-30 mass parts with respect to 100 mass parts of diene rubbers, Preferably it is 5-20 mass parts.

(Other ingredients)
In the rubber composition of the present invention, in addition to the above-described components, a vulcanization or crosslinking agent; a vulcanization or crosslinking accelerator; various fillers such as zinc oxide, carbon black, clay, talc, calcium carbonate; silane cup Various additives that are generally blended in rubber compositions such as a ring agent, an anti-aging agent, and a plasticizer can be blended, and these additives are kneaded by a general method to form a composition and vulcanized. Or it can be used to crosslink. The blending amounts of these additives can be set to conventional general blending amounts as long as the object of the present invention is not violated.

  The rubber composition of the present invention is suitable for producing a pneumatic tire in accordance with a conventional method for producing a pneumatic tire, and is preferably applied to a tread, particularly a cap tread.

  EXAMPLES Hereinafter, although an Example and a comparative example further demonstrate this invention, this invention is not restrict | limited to the following example.

Standard Example 1, Examples 1-3 and Comparative Examples 1-3
Sample Preparation In the formulation (parts by mass) shown in Table 1, the components except the vulcanization accelerator and sulfur were kneaded for 5 minutes with a 1.7 liter closed Banbury mixer, and then added with the vulcanization accelerator and sulfur. The rubber composition was obtained by kneading. Next, the obtained rubber composition was press vulcanized in a predetermined mold at 160 ° C. for 20 minutes to obtain a vulcanized rubber test piece, and an unvulcanized rubber composition and vulcanized rubber were tested by the following test method. The physical properties of the test piece were measured.

Mooney viscosity: The viscosity of unvulcanized rubber at 100 ° C. was measured according to JIS K6300 using the rubber composition. The results were expressed as an index with the value of standard example 1 being 100. The lower this value, the lower the viscosity and the better the workability.
tan δ (0 ° C.): In accordance with JIS K6394, using a viscoelastic spectrometer manufactured by Iwamoto Seisakusho, tan δ (temperature of elongation = 20 ± 2%, frequency = 20 Hz, temperature 0 ° C.) 0 ° C.) was measured, and wet grip performance was evaluated with this value. The results are shown as an index with the standard example 1 being 100. It shows that wet grip performance is so favorable that this value is high.
tan δ (60 ° C.): In accordance with JIS K6394, using a viscoelastic spectrometer manufactured by Iwamoto Seisakusho Co., Ltd., tan δ (60 ° C.) and the rolling resistance was evaluated with this value. The results are shown as an index with the standard example 1 being 100. The lower this value, the lower the rolling resistance and the lower the fuel consumption.
Abrasion resistance: Measured in accordance with JIS K6264 using a Lambourn abrasion tester under a load of 4.0 kg (= 39 N) and a slip ratio of 30%. The results are shown as an index with the standard example 1 being 100. It shows that abrasion resistance is so favorable that this value is high.
The results are also shown in Table 1.

* 1: SBR-1 (Nipol 9548 manufactured by Nippon Zeon Co., Ltd., oil extended amount = 37.5 parts by mass with respect to 100 parts by mass of SBR)
* 2: SBR-2 (Nipol NS530 manufactured by Nippon Zeon Co., Ltd., oil extended amount = 20 parts by mass with respect to 100 parts by mass of SBR)
* 3: NR (SIR20)
* 4: Silica (9000GR manufactured by EVONIK, BET specific surface area = 235 m ² / g)
* 5: Carbon black (N234 manufactured by Cabot Japan Co., Ltd.)
* 6: Silane coupling agent (Si69, bis (3-triethoxysilylpropyl) tetrasulfide manufactured by EVONIK)
* 7: Zinc oxide (3 types of zinc oxide manufactured by Shodo Chemical Industry Co., Ltd.)
* 8: Stearic acid (Stearic acid YR manufactured by NOF Corporation)
* 9: Anti-aging agent (Santoflex 6PPD manufactured by Solutia Europe)
* 10: Process oil (Extract No. 4 S manufactured by Showa Shell Sekiyu KK)
* 11: Resin -1 (Rutgers Co. Nobaresu L800, modified with phenol was _{C 9} petroleum resin, Mw = 300, softening point -40 to-30 ° C., hydroxyl value = 0.1 wt%, liquid at room temperature)
* 12: Resin-2 (YSHARA Chemical Co., Ltd. YS resin TO-125, terpene styrene resin, Mw = 2000, softening point 120-130 ° C., hydroxyl value = 0.0 wt%, solid at room temperature)
* 13: Resin -3 (Rutgers Co. Nobaresu L100, modified with phenol was _{C 9} petroleum resin, Mw = 300, softening point -40 to-30 ° C., hydroxyl value = 0.1 wt%, liquid at room temperature)
* 14: Resin-4 (Novales C10 manufactured by Rutgers, Coumarone Indene resin, Mw = 300, softening point 5-15 ° C., hydroxyl value = 0.0 wt%, liquid at room temperature)
* 15: Sulfur (Karuizawa Smelter Refinery sulfur)
* 16: Vulcanization accelerator-1 (Noxeller CZ-G manufactured by Ouchi Shinsei Chemical Co., Ltd.)
* 17: Vulcanization accelerator-2 (Perkacit DPG manufactured by Flexsys)

As apparent from the results in Table 1 above, the rubber compositions obtained in Examples 1 to 3, with respect to the diene rubber, C ₉ petroleum resins and silica modified with phenolic compounds with specific properties Therefore, the wet grip performance, rolling resistance, workability and wear resistance are all improved with respect to the conventional representative standard example 1. In particular, Example 3 in which the aromatic modified terpene resin was blended further improved wet grip performance, rolling resistance, workability and wear resistance.
In contrast, Comparative Example 1, without using the C ₉ petroleum resin modified with phenolic compounds, since the example using only terpene styrene resin is an aromatic modified terpene resin in its instead, rolling resistance Worsened.
Comparative Example 2 without using the C ₉ petroleum resin modified with phenolic compounds, because the example was blended unmodified coumarone-indene resin to that instead, wet grip performance, rolling resistance is deteriorated.
In Comparative Example 3, since the amount of silica was less than the lower limit specified in the present invention, wet grip performance and rolling resistance were deteriorated.

Claims (4)

To diene rubber 100 parts by weight, the weight average molecular weight Mw of 200 to 1000, and a softening point in the range of -40~20 ℃, 1~30 mass _{C 9} petroleum resins modified with phenolic compounds A rubber composition comprising 80 parts by weight and 200 parts by weight of silica. Phenolic modified C ₉ petroleum resin compound, the rubber composition according to claim 1, characterized in that the modified C ₉ petroleum resin with phenol.   The rubber composition according to claim 1 or 2, further comprising 1 to 30 parts by mass of an aromatic modified terpene resin with respect to 100 parts by mass of the diene rubber.   A pneumatic tire using the rubber composition according to claim 1 as a tread.