JP2002097303A - Tread rubber composition and tire made by using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a tread rubber composition extensively improved in wet grip performance, resisting performance to abrasion, and resisting performance to heat generation, while keeping dry grip performance, and to provide a tire made by using the same. SOLUTION: This tread rubber composition contains (A) a natural rubber and/or a diene-based synthetic rubber, (B) a urethane-based particulate material, and (C) a reinforcing filler, wherein the content of the urethane-based particulate material (B) is 1-20 pts.wt. and the total content of the urethane-based particulate material (B) and the reinforcing filler (C) is 30-200 pts.wt. based on 100 pts.wt. of the rubber (A), respectively. The tire is made by using the same as its tread.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a rubber composition for a tread and a tire using the same. More specifically, for a tread capable of providing a tire with improved grip performance (wet grip performance), abrasion resistance, and heat generation resistance on wet roads while maintaining grip performance on dry roads (dry grip performance). The present invention relates to a rubber composition and a tire using the tread rubber composition for a tread.

[0002]

2. Description of the Related Art With the recent demand for energy saving in society, the characteristics required for tires have become stricter year by year, and one of them is to reduce the heat generation of tire rubber for the purpose of saving fuel consumption of automobiles. Is raised. In general, in order to reduce heat generation, that is, to reduce rolling resistance, it is conceivable to reduce the filling amount of carbon black or use carbon black having a large particle size, but in any case, wet grip performance, reinforcing property, abrasion resistance performance are considered. It is known to decrease.

On the other hand, hydrous silicic acid is known as a filler that balances the heat generation resistance (low heat generation), the wet grip performance, the reinforcing property and the wear resistance. However, hydrous silicic acid has a lower storage elastic modulus of the rubber composition than carbon black having the same specific surface area, and therefore is inferior in dry grip performance. The storage elastic modulus can be increased by increasing the amount of hydrous silicic acid or increasing the specific surface area, but the heat generation resistance (low heat generation) decreases.

Although various proposals have been made to solve these problems, there are still rubber compositions having a high balance between dry grip performance, wet grip performance, abrasion resistance and heat generation performance. It is not at present.

[0005]

SUMMARY OF THE INVENTION An object of the present invention is to provide a tread rubber composition and a tread rubber composition capable of improving wet grip performance, abrasion resistance and heat generation resistance without deteriorating dry grip performance. An object of the present invention is to provide a tire using an object as a tread.

[0006]

Means for Solving the Problems As a result of intensive research and development to solve the above-mentioned problems, urethane-based particles were obtained by replacing a part of reinforcing filler such as carbon black and silica particles with urethane-based particles. Found that the abrasion resistance is improved because the strain is locally dispersed to relieve the stress. In addition, the urethane-based particles effectively prevent the agglomeration of the reinforcing filler and reduce the hysteresis loss, thereby improving the heat generation resistance. The elasticity of the urethane-based particles themselves improves grip performance (grounding property). I found that.

That is, the present invention comprises (A) a natural rubber and / or a diene-based synthetic rubber, (B) a urethane-based particle and (C) a reinforcing filler, and a rubber (A) 100
The content of the urethane-based particles (B) is 1 to 20 parts by weight.
The total content of the parts by weight and the reinforcing filler (C) is 30 to 2
The rubber composition for a tread, wherein the average particle diameter of the urethane-based particles (B) is 1 to 100 μm.
m, wherein the rubber composition for a tread and the reinforcing filler (C) are carbon black or a general formula (1): nM · xSiO _y · zH ₂ O (1) (where M is aluminum, calcium, magnesium And at least one metal element, oxide or hydroxide selected from the group consisting of and titanium, wherein n is 1 to 5,
x represents a number in the range of 0 to 10, y represents a number in the range of 2 to 5, and z represents a number in the range of 0 to 10. The present invention relates to the above-mentioned rubber compositions for treads each containing an inorganic compound particle represented by the formula (1), and tires using the above-mentioned rubber compositions for treads in treads.

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION The rubber composition for a tread of the present invention comprises (A) a natural rubber and / or a diene-based synthetic rubber,
It contains (B) urethane-based particles and (C) a reinforcing filler.

In the rubber composition for a tire tread of the present invention, a natural rubber and / or a diene-based synthetic rubber is used as the rubber (A). Here, as the diene-based synthetic rubber, for example, styrene-butadiene rubber (SB
R), butadiene rubber (BR), isoprene synthetic rubber (IR), acrylonitrile-butadiene rubber (NB
R), isobutylene-isoprene rubber (IIR), chloroprene rubber (CR) and the like. The rubber (A) may be used alone or in combination of two or more.

Various particles are used as the urethane particles (B). The urethane-based particles (B) may be used alone or in combination of two or more.

The content of the urethane particles (B) is 1 to 20 parts by weight, preferably 1 to 15 parts by weight, per 100 parts by weight of the rubber (A). If the content of the urethane-based particles (B) is less than 1 part by weight, the improvement of the grip performance and the heat generation resistance is insufficient, and if it exceeds 20 parts by weight, the wear resistance and the heat generation resistance decrease.

The urethane-based particles (B) have an average particle diameter of 1 to 1.
It is preferably 100 μm, particularly preferably 1 to 20 μm. If the average particle diameter of the urethane-based particles (B) is less than 1 μm, the aggregation of the reinforcing filler such as carbon black cannot be suppressed, so that the hysteresis loss cannot be reduced and the heat generation resistance tends to be deteriorated. On the other hand, if the thickness exceeds 100 μm, the urethane-based particles may not be able to disperse the strain locally, and the abrasion resistance tends to deteriorate.

Conventionally, there has been known a method of filling a rubber composition with an aggregate obtained by grafting small particles on the surface of large particles in order to improve the wear resistance. Usually, the addition of a fine substance improves the wear resistance, but the fine substance is easily aggregated because the small substance is small. When the fine substance is aggregated, the apparent particle size increases, and the effect of improving the wear resistance decreases. In addition, the aggregate has a larger hysteresis loss than a single substance having the same diameter, so that the rolling resistance is increased. In this method, particles having different particle sizes are condensed to prevent the particles from agglomerating, and the abrasion resistance is improved.

According to the present invention, not only the wear resistance but also the grip performance and the heat generation resistance are improved by using urethane-based particles which are not grafted and are larger than the above-mentioned aggregates. Is what you do.

The reinforcing filler (C) can be arbitrarily selected from those conventionally used in rubber compositions for tire treads, and is preferably mainly carbon black or silica particles. The nitrogen adsorption specific surface area of carbon black is preferably from 80 to ²⁰⁰ m ² / g. Nitrogen adsorption specific surface area of carbon black is 8
If it is less than 0 m ² / g, the wear resistance tends to decrease,
If it exceeds 200 m ² / g, the heat resistance tends to decrease. The nitrogen adsorption specific surface area of silica is 100-280m
It is preferably ² / g. If the nitrogen adsorption specific surface area of the silica is less than 100 m ² / g, the abrasion resistance tends to decrease, and if it exceeds 280 m ² / g, the heat generation resistance tends to decrease.

The reinforcing filler (C) has the general formula
(1): nM · xSiO_y・ ZH_TwoO (1) (where M is aluminum (Al), calcium (C
a), from magnesium (Mg) and titanium (Ti)
At least one metal element or oxide selected from the group consisting of
Or a hydroxide, n is 1 to 5, x is 0 to 10, y
Represents a numerical value in the range of 2 to 5, and z represents a numerical value in the range of 0 to 10. )
Those containing inorganic compound particles to be used are also preferably used.
It is. In the general formula (1), when both x and z are 0
Those corresponding to the formula (1) are A1, Ca, Mg and Ti
At least one metal or oxide selected from the group consisting of
Or it becomes hydroxide. Here, represented by the general formula (1)
Examples of inorganic compounds include aluminum hydroxide (Al)
(OH)_Three), Alumina (Al_TwoO_Three, Al_TwoO_Three・ 3H_TwoO
(Hydrate)), clay (Al_TwoO_Three・ 2SiO_Two), Khao
Phosphorus (Al_TwoO_Three・ 2SiO_Two・ 2H_TwoO), pyrophylla
(Al_TwoO_Three・ 4SiO_Two・ H_TwoO), bentonite
(Al_TwoO_Three・ 4SiO_Two・ 2H_TwoO), aluminum silicate
(Al_TwoSiO_Five, Al_Four(SiO_Two)_Three・ 5H_TwoO
Etc.), aluminum calcium silicate (Al_TwoO_Three・ Ca
O.2SiO_Two), Calcium hydroxide (Ca (O
H)_Two), Calcium oxide (CaO), calcium silicate
(Ca_TwoSiO_Four), Magnesium calcium silicate
(CaMgSiO_Four), Magnesium hydroxide (Mg (O
H)_Two), Magnesium oxide (MgO), talc (Mg
O ・ 4SiO_Two・ H_TwoO), Attapulgite (5MgO
・ 8SiO_Two・ 9H_TwoO), aluminum magnesium oxide
(MgO ・ Al_TwoO_Three), Titanium white (TiO_Two), Chita
Black (Ti_nO _2n-1). In addition, titanium
Black (Ti_nO_2n-1)), N is a numerical value close to 1
You. Among these, hydroxyl hydroxide is used to improve grip performance.
Luminium, alumina and the like are particularly preferably used.

The center particle diameter of the inorganic compound particles is 0.0
Preferably it is 1 to 10 μm. If the center particle diameter of the inorganic compound particles is less than 0.01 μm, grip performance tends to decrease, and if it exceeds 10 μm, wear resistance tends to decrease.

In the present invention, the reinforcing filler (C) may be used alone or in combination of two or more.

The content of the reinforcing filler (C) is preferably 5 to 200 parts by weight based on 100 parts by weight of the rubber component. If the amount of the reinforcing filler (C) is less than 5 parts by weight, the abrasion resistance tends to decrease, and if it exceeds 200 parts by weight, the heat generation resistance tends to decrease.

The total content of the urethane particles (B) and the reinforcing filler (C) is 30 to 200 parts by weight, preferably 50 to 100 parts by weight. If the total content is less than 30 parts by weight, the abrasion resistance will be reduced, and if it exceeds 200 parts by weight, the heat generation resistance will be reduced.

The ratio (weight ratio) between the urethane particles (B) and the reinforcing filler (C) is 20:80 to 1: 1.
Preferably it is 99. If the content of the urethane-based particles is less than 1% by weight, the heat generation resistance tends to decrease.
If it exceeds 0% by weight, the wear resistance tends to decrease.

In the rubber composition for a tire tread of the present invention, the components (B) and (C) are used in the above-mentioned ratio, so that the urethane-based particles ( B) Since the component forms a network structure, the grounding property and rigidity are improved, so that wet grip performance and abrasion resistance are improved, and furthermore, the heat generation performance is greatly improved due to the elasticity characteristic of the urethane-based particles themselves, resulting in low heat resistance. Rolling resistance can be achieved.

Further, the rubber composition of the present invention can contain a silane coupling agent. The amount of the silane coupling agent is preferably 2 to 20% by weight based on the weight of the inorganic filler. The amount of the silane coupling agent is 2
If the amount is less than 20% by weight, the reinforcing effect of the inorganic filler tends to be insufficient. If the amount is more than 20% by weight, the effect is not improved and the cost tends to be high.

As the silane coupling agent, those conventionally used in combination with silica can be used without particular limitation.

Specific examples of the silane coupling agent include, for example, bis (3-triethoxysilylpropyl) tetrasulfide, bis (2-triethoxysilylethyl) tetrasulfide, and bis (3-trimethoxysilylpropyl) tetrasulfide. Sulfide, bis (2-trimethoxysilylethyl) tetrasulfide, 3-mercaptopropyltrimethoxysilane, 3-mercaptopropyltriethoxysilane, 2-mercaptoethyltrimethoxysilane, 2-mercaptoethyltriethoxysilane,
3-nitropropyltrimethoxysilane, 3-nitropropyltriethoxysilane, 3-chloropropyltrimethoxysilane, 3-chloropropyltriethoxysilane, 2-chloroethyltrimethoxysilane, 2-chloroethyltriethoxysilane, 3- Trimethoxysilylpropyl-N, N-dimethylthiocarbamoyltetrasulfide, 3-triethoxysilylpropyl-N, N-dimethylthiocarbamoyltetrasulfide, 2-trimethoxysilylethyl-N, N-dimethylthiocarbamoyltetrasulfide, 3 Trimethoxysilylpropyl benzothiazole tetrasulfide, 3-triethoxysilylpropyl benzothiazole tetrasulfide, 3
-Triethoxysilylpropyl methacrylate monosulfide, 3-trimethoxysilylpropyl methacrylate monosulfide and the like. These may be used alone or in combination of two or more. Among them, bis (3-triethoxysilylpropyl) tetrasulfide and 3-mercaptopropyltrimethoxysilane are preferable because the effect of adding the silane coupling agent is large and the cost is superior.

The rubber composition of the present invention may contain, in addition to the above components, various chemicals usually used in the rubber industry, for example, vulcanizing agents such as sulfur, various vulcanization accelerators, various softening agents, Additives such as antioxidants, zinc oxide, stearic acid, antioxidants, and antiozonants can be added.

The tire of the present invention is produced by a usual method using the rubber composition for a tread of the present invention. That is, the rubber composition for a tread according to the present invention containing the various chemicals described above is extruded into a member for a tread in an unvulcanized stage, if necessary, and pasted and molded by a normal method on a tire molding machine. To form an unvulcanized tire. The unvulcanized tire is heated and pressed in a vulcanizer to obtain a tire.
The tire of the present invention thus obtained has an excellent balance of dry grip performance, wet grip performance, abrasion resistance performance, heat generation resistance (low heat generation), and the like.

[0028]

EXAMPLES Hereinafter, the present invention will be described specifically with reference to Examples, but the present invention is not limited thereto.

Hereinafter, the chemicals used in Examples and Comparative Examples are shown together. Natural rubber: RSS # 3 manufactured by Tech Bee Hang Co. SBR: SBR1502 manufactured by JSR Corporation Silica: Ultrasil VN3 manufactured by Degussa
(Nitrogen adsorption specific surface area: 210 m ² / g) Carbon black: Showa Cabot Co. Ltd. SHOWBLACK N220 (nitrogen adsorption specific surface area: 125m ² /
g) Clay: Suprex (center particle diameter: 0.3 μm, BET specific surface area: 22 to 26 m ² / g, DBP oil absorption: 35 to 40) manufactured by JMH Huber Co.
g / 100 g, pH: 4.5-5.5) Urethane-based particles A: manufactured by Dainippon Ink and Chemicals, Inc. (average particle diameter: 4 μm) Urethane-based particles B: manufactured by Dainippon Ink and Chemicals, Inc. ( Urethane-based particles C: Sekisui Chemical Co., Ltd. (average particle size: 110 μm) Silane coupling agent: Si69 (bis (3-triethoxysilylpropyl) tetrasulfide) manufactured by Degussa Aroma Oil: JOMO Process X140 manufactured by Japan Energy Co., Ltd. Antioxidant: Nocrack 6 manufactured by Ouchi Shinko Chemical Co., Ltd.
C (N- (1,3-dimethylbutyl) -N'-phenyl-p-phenylenediamine) Stearic acid: Stearic acid manufactured by NOF CORPORATION Zinc oxide: Zinc flower No. 1 manufactured by Mitsui Kinzoku Mining Co., Ltd. Sulfur: powder sulfur manufactured by Tsurumi Chemical Co., Ltd. Vulcanization accelerator: Noxeller C manufactured by Ouchi Shinko Chemical Industry Co., Ltd.
Z (N-cyclohexyl-2-benzothiazolylsulfenamide)

Hereinafter, a method for evaluating a vulcanized rubber will be described. (1) Wet grip performance Wet grip performance is a British Standard Portable Skid Tester (Stanley London)
Was used to measure the wet skid resistance, and Comparative Example 1 was set to 100 to indicate an index. The larger the value, the higher the wet grip performance.

(2) Dry grip performance Dry grip performance was measured at size 195 /
The vehicle was driven on a dry asphalt road surface using 65R15 tires, and the control stability at the time of steering at that time was evaluated by a test driver. The larger the value, the higher the dry grip performance.

(3) Heat generation resistance The reciprocal of the value of tan δ when measured at a dynamic strain amplitude of 2%, a frequency of 10 Hz, and a temperature of 70 ° C. using a spectrometer manufactured by Ueshima Seisakusho Co., Ltd. is defined as 100 in Comparative Example 1. Exponential display. The larger the value, the higher the heat resistance.

(4) Abrasion resistance Using a Lambourn abrasion tester, a slip ratio of 2 at room temperature was used.
The test was performed under the condition of 0%, and the reciprocal of the abrasion amount was indicated as an index with Comparative Example 1 being 100. The larger the value, the higher the abrasion resistance performance.

Examples 1 to 4 and Comparative Examples 1 to 6 According to the compounding recipe shown in Table 1, kneading and compounding were carried out to obtain various test rubber compositions. 170 ° C. of these rubber compositions
For 20 minutes to obtain a vulcanized product, which was tested for the above-mentioned properties. Table 1 shows the results.

[0035]

[Table 1]

As is clear from Table 1, the rubber compositions of Examples 1 to 4 were able to improve wet grip performance, abrasion resistance and heat generation without reducing dry grip performance.

[0037]

As described above, it is possible to provide a rubber composition for a tread and a tire in which wet grip performance, abrasion resistance and heat generation resistance are significantly improved while maintaining dry grip performance.

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Claims (4)

[Claims] 1. A rubber composition containing (A) a natural rubber and / or a diene-based synthetic rubber, (B) urethane-based particles and (C) a reinforcing filler, and 100 parts by weight of the rubber (A), based on urethane-based particles ( The content of B) is 1 to 20 parts by weight, and the total content of the urethane-based particles (B) and the reinforcing filler (C) is 3
0 to 200 parts by weight of a rubber composition for a tread. 2. The urethane-based particles (B) have an average particle size of 1
The rubber composition for a tread according to claim 1, which has a thickness of from 100 to 100 µm. 3. The reinforcing filler (C) is carbon black or a general formula (1): nM · xSiO _y · zH ₂ O (1) (where M is a group consisting of aluminum, calcium, magnesium and titanium) Represents at least one selected metal element, oxide or hydroxide, n is 1 to 5,
x represents a numerical value in the range of 0 to 10, y represents a numerical value in the range of 2 to 5, and z represents a numerical value in the range of 0 to 10. 2. The rubber composition for a tread according to claim 1, which contains inorganic compound particles represented by the formula (1). 4. A tire using the tread rubber composition according to claim 1, 2 or 3 for a tread.