JPH115871A - Rubber composition, cured rubber and tire - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a rubber composition useful as a curable rubber stock for e.g. tires excellent in wear resistance and on-ice performance by incorporating a continuous form of specific shape in a rubber matrix composed of rubber component(s) and specific carbon black. SOLUTION: This rubber composition is obtained by incorporating a rubber matrix which is prepared by compounding 100 pts.wt. of at least one kind of rubber component selected from natural rubber and diene rubbers with >=10 (pref. 10-100) pts.wt. of carbon black with the dibutyl terephthalate absorption (DBP) and nitrogen adsorption specific surface area (N2 SA) satisfying the relationships (1): (DBP)>=0.186×(N2 SA)+89 and (2): (DBP)>=1000/(N2 SA)+100, with 1-20 (pref. 5-10) pts.wt., based on 100 pts.wt. of the rubber component(s), of a continuous form >=3 (pref. 5-100) in the ratio of the average diameter to average length (e.g. nylon fiber).

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a rubber composition, a vulcanized rubber and a tire, and more particularly, to a dramatic improvement in braking / driving performance on ice and snow road surfaces without impairing wear resistance on dry road surfaces. The present invention relates to a vulcanized rubber which can be suitably used for an improved tire, a tread of the tire, and a rubber composition which can be suitably used as a raw material of the vulcanized rubber.

[0002]

2. Description of the Related Art Since spike tires have been regulated, braking / driving performance on ice and snow road surfaces where water film tends to occur (performance on ice)
In particular, various studies on treads for studless tires have been actively conducted in order to improve the tread.
On an icy and snowy road surface, the water film causes a reduction in the coefficient of friction between the studless tire and the icy and snowy road surface. For this reason, the ability of the tread to remove the water film and the edge effect of the studless tire greatly affect the performance on ice. Therefore, in order to improve the performance on ice of the studless tire, it is necessary to improve the water film removing ability and the edge effect of the tread.

[0003] Japanese Patent No. 2568502 discloses a technique in which a tread is made of foamed rubber, and the water film removing ability and the edge effect are improved by fine irregularities due to closed cells in the foamed rubber. However, even if such a foamed rubber containing only closed cells is used, the performance on ice cannot be improved to a level that sufficiently satisfies the level required in the market. JP-A-8-85738 discloses that a rubber composition having excellent hydrophobicity and water repellency is used for a tread. However, also in this case, similarly to the above, the performance on ice cannot be sufficiently improved to the extent that the market demand level is satisfied.

On the other hand, JP-A-4-38207 discloses that
A technique is described in which a short fiber-containing foamed rubber is used for a tread to form micro grooves on the surface of the tread. However, in this case, the short fibers curl due to heat shrinkage during vulcanization, or the short fibers are pushed into the grooves of the mold, that is, the sipe portions, and are bent in the tread.
For this reason, even if the tread wears due to running, if the worn surface and the short fibers are not substantially parallel, the short fibers do not easily come off from the tread, and the microscopic grooves as originally aimed are efficiently formed. It is not formed and the coefficient of friction on ice is not sufficiently improved. Further, the micro grooves may be crushed when the load applied to the tire is large. Further, in this case, there is a problem that the wear resistance is significantly reduced.

On the other hand, Japanese Patent Application Laid-Open No. 4-110212 discloses that by dispersing hollow fibers in a tread, water flowing between an ice surface and a tread contact surface can be eliminated in a hollow portion of the hollow fibers. A tire is disclosed. However, in this case, when kneading the hollow fiber with rubber, the hollow fiber is crushed due to pressure during molding, rubber flow, temperature, and the like, and the hollow fiber cannot actually maintain the hollow shape. However, there is still a problem that the water removal performance is not sufficient. Further, in this case, there is a problem that the wear resistance is significantly reduced.

[0006]

SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned conventional problems and achieve the following objects. That is, the present invention has an excellent ability to remove water generated on an ice surface, has a large coefficient of friction with an ice surface, does not impair abrasion resistance on a dry road surface, and performs braking and driving on an ice and snow road surface. Tires with dramatically improved performance (performance on ice)
It is an object of the present invention to provide a vulcanized rubber which can be suitably used for a structure or the like which needs to suppress a slip on ice such as a tread of the tire, and a rubber composition which can be suitably used as a raw material of the vulcanized rubber. And

[0007]

Means for solving the above problems are as follows. That is, <1> a rubber matrix containing at least one rubber component selected from natural rubber and diene-based synthetic rubber, and at least 10 parts by weight of carbon black with respect to 100 parts by weight of the rubber component; 1 to 20 parts by weight of a long body having a ratio (L / D) of the average length (L) to the average diameter (D) of at least 3 with respect to the weight of the carbon black. Is the formula (1): (DBP)
≧ 0.186 × (N ₂ SA) +89, and equation (2):
A rubber composition satisfying (DBP) ≧ 1000 / (N ₂ SA) +100. <2> The rubber composition according to <1>, wherein the rubber matrix contains a foaming agent. <3> The above <1>, wherein the long body contains at least short fibers.
Or it is a rubber composition as described in <2>. <4> The above-mentioned <1>, wherein the elongated body contains at least an elongated resin whose viscosity is lower than the viscosity of the rubber matrix until the temperature of the rubber composition reaches the maximum vulcanization temperature during vulcanization. Or it is a rubber composition as described in <2>. <5> The rubber composition according to <4>, wherein the elongated resin contains a crystalline polymer, and the melting point of the resin is lower than the maximum vulcanization temperature. <6> The rubber composition according to <4> or <5>, wherein the long resin softens at a temperature equal to or lower than an extrusion temperature.

<7> A vulcanized rubber obtained by vulcanizing the rubber composition according to <3> and containing short fibers. <8> A vulcanized rubber obtained by vulcanizing the rubber composition according to any one of <4> to <6> and having long bubbles. <9> The vulcanized rubber according to <7> or <8>, wherein the average foaming ratio is 3 to 40%.

<10> A pair of bead portions, a carcass connected to the bead portions in a toroidal shape, a belt and a tread for clinching a crown portion of the carcass, and at least the tread is <7> to <9
A tire comprising the vulcanized rubber described in any one of the above items. <11> The tire according to <10>, wherein at least one of the short fiber and the long bubble is oriented along the tire circumferential direction.

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION The rubber composition, vulcanized rubber and tire of the present invention will be described below in detail.

(Rubber Composition) The rubber composition of the present invention comprises a rubber matrix and an elongated body. The rubber matrix contains a component excluding the elongated body in the rubber composition of the present invention. Specifically, at least one rubber component selected from natural rubber and diene-based synthetic rubber and carbon black. At least including, further, a foaming agent,
It contains other components appropriately selected as necessary, such as a foaming aid, an inorganic filler, and a coupling agent.

--Rubber matrix ---- Rubber component-- The diene-based synthetic rubber is not particularly limited and may be appropriately selected from known ones according to the purpose. For example, styrene-butadiene copolymer may be used. Coalescence, polyisoprene, polybutadiene and the like. These are 1
Species may be used alone or in combination of two or more. Among these diene-based synthetic rubbers, cis-1,4 has a low glass transition temperature and a large effect on ice.
-Polybutadiene is preferred, and those having a cis content of 90% or more are particularly preferred.

-Carbon Black- As the carbon black, it is necessary that "(DBP)" and "(N ₂ SA)" satisfy the relationship shown in the following formulas (1) and (2). is there. Formula (1): (DBP) ≧ 0.186 × (N ₂ SA) +8
9 Formula (2): (DBP) ≧ 1000 / (N ₂ SA) +10
0 The “(DBP)” refers to the dibutyl terephthalate absorption amount (ml / 10) specified in ASTM D2414-90.
0g). The “(N ₂ SA)” represents A
It means the nitrogen adsorption specific surface area (m ² / g) specified in STM D3037-89.

The range of carbon black that satisfies the above formulas (1) and (2) and can be used in the present invention is the shaded area defined by two lines in FIG. 1 (that is, the two lines in FIG. 1). Is a set part of the range in which the value of (DBP) is equal to or greater than the value of (DBP) on the higher line when the value of (N ₂ SA) on the horizontal axis is used as a reference. .

Carbon black satisfying the above formula (1) is called "high-structure carbon black" in comparison with standard grade carbon black such as ASTM carbon black. The “high-structure carbon black” is generally preferred because it has excellent abrasion resistance as compared with standard-grade carbon black and can be easily oriented in the extrusion direction during extrusion of the rubber composition. Further, when this "high-structure carbon black" and the elongated body are combined, a more improved orientation can be obtained as compared with each orientation when each is used alone in the rubber composition. It is advantageous. As for the carbon black satisfying the above formula (2), the smaller (N ₂ SA) the carbon black (ie, “large particle size carbon black” or “lower carbon black”), the larger (DBP) (“high structure”). Is required.

If the carbon black does not satisfy the above-mentioned formula (1), even if a vulcanized rubber obtained by vulcanizing the rubber composition is used for a tread of a tire, the orientation due to a small DBP is obtained. Due to the low height, sufficient performance on ice cannot be obtained,
If the expression (2) is not satisfied, the wear resistance cannot be sufficiently improved due to the small DBP. Furthermore,
If the carbon black does not satisfy the above formulas (1) and (2), other performances such as ice performance, abrasion resistance and running performance on dry roads (grip performance) are not sufficient.
On the other hand, when the carbon black satisfies the above formulas (1) and (2), such a situation does not occur, the orientation of the elongated body can be improved, and the performance on ice and the abrasion resistance can be improved. Is preferred in that it can be effectively improved.

The value of “(N ₂ SA)” is not particularly limited, but is at least 50 from the viewpoint of wear resistance.
(M ² / g) (ie, 50 (m ² / g) or more) is preferable, and at least 70 (m ² / g) (ie, 70 (m ² / g)
g) and above are more preferred. The value of “(DBP)” is not particularly limited, but is preferably 250 (ml / 100 g) or less (ie, 250 (ml / 100 g) or less) at most from the viewpoint of productivity of carbon black. 200 (ml / 100 g) (that is, 200 (ml / 100 g)
/ 100 g) or less).

The type of the carbon black is not particularly limited as long as it satisfies the formulas (1) and (2), and commercially available products can be suitably used.
As the commercially available products, for example, Asahi # 7 manufactured by Asahi Carbon Co., Ltd.
3H and the like. The carbon black may be used alone or in combination of two or more.

The content of the carbon black in the rubber composition must be at least 10 parts by weight (ie, 10 parts by weight or more) based on 100 parts by weight of the rubber component, and is 10 to 120 parts by weight. Is preferably 10
-100 parts by weight are particularly preferred. In the present invention, as the content of the carbon black, the upper limit or lower limit of any of the numerical ranges or the value of any of the contents adopted in the examples described below as a lower limit, any of the numerical range A numerical range in which the upper limit or lower limit or the content of any of the contents employed in the examples described later is the upper limit is also preferable. If the content is less than 10 parts by weight, the vulcanized rubber obtained by vulcanizing the rubber composition is not preferable because the wear resistance of the vulcanized rubber is remarkably reduced. Meanwhile, 1
When the amount is 0 part by weight or more, such a case does not occur, and it is preferable in that the abrasion resistance of the vulcanized rubber can be improved.

-Other components-The other components are not particularly limited as long as they do not impair the purpose of the present invention, and can be appropriately selected depending on the purpose. Examples thereof include a vulcanizing agent such as a softener and sulfur. , A vulcanization accelerator such as dibenzothiazyl disulfide, a vulcanization aid, N-cyclohexyl-2-benzothiazyl-sulfenamide, N
-Antioxidants such as oxydiethylene-benzothiazyl-sulfenamide, zinc oxide, stearic acid, antiozonants, coloring agents, antistatic agents, lubricants, antioxidants, additives such as softeners, etc. Various compounding agents used in the rubber industry can be appropriately used. In the present invention, commercially available products can be suitably used for the other components.

In the present invention, a foaming agent can be particularly preferably used as the other component. By using at least the foaming agent, the vulcanized rubber obtained by vulcanizing the rubber composition can be made into a foamed rubber having a high foaming rate, and when the long body is a long resin. Is advantageous in that the long resin can be efficiently made into long bubbles.

Examples of the foaming agent include dinitrosopentamethylenetetraamine (DPT), azodicarbonamide (ADCA), dinitrosopentastyrenetetramine, a benzenesulfonylhydrazide derivative, oxybisbenzenesulfonylhydrazide (OBSH),
Ammonium bicarbonate, nitrososulfonylazo compound,
N, N′-dimethyl-N, N′-dinitrosophthalamide, toluenesulfonylhydrazide, P-toluenesulfonylsemicarbazide, P, P′-oxy-bis (benzenesulfonylsemicarbazide) and the like. These may be used alone or in combination of two or more. Among these blowing agents, dinitrosopentamethylenetetraamine (DP
T) and azodicarbonamide (ADCA) are preferred.

In the present invention, when the above-mentioned foaming agent is used, it is preferable to further use a foaming aid in view of the fact that foaming can be carried out efficiently. Examples of the foaming aid include urea, zinc stearate, zinc benzenesulfinate, zinc white, and the like, which are usually used in the production of foamed products. These may be used alone or in combination of two or more. Among these foaming assistants, urea, zinc stearate, zinc benzenesulfinate and the like are preferable.

In the present invention, an inorganic filler can be preferably used as the other component. The use of the inorganic filler is advantageous in that the traveling performance (grip performance) of a vulcanized rubber obtained by vulcanizing the rubber composition on a wet road surface can be improved.

As the inorganic filler, for example, Al ₂
O ₃ , ZnO, TiO ₂ , SiC, Si, C, Si
Ceramics such as O ₂ , ferrite, zirconia, MgO, Fe, Co, Al, Ca, Mg, Na, Cu, Cr
Such as metals, alloys composed of these metals, nitrides, oxides, hydroxides, carbonates, silicates, sulfates and the like of these metals, as well as brass, stainless steel, etc., glass, carbon, carbon random, mica , Zeolite, kaolin, asbestos, montmorillonite, bentonite, graphite, silica, clay and the like. These may be used alone or in combination of two or more. Among them, Al ₂ O ₃ , SiC, Si, C,
SiO ₂ , Al, silica and the like are preferred.

The content of the inorganic filler in the rubber composition is 10 parts by weight based on 100 parts by weight of the rubber component.
0 parts by weight or less is preferable, and 10 to 80 parts by weight is preferable. When the content of the inorganic filler in the rubber composition exceeds 100 parts by weight based on 100 parts by weight of the rubber component, the vulcanized rubber obtained by vulcanizing the rubber composition is used for a tread or the like of a tire. However, it is not preferable because the performance on ice decreases with an increase in the elastic modulus.

The inorganic filler is preferably surface-treated with the following coupling agent. When the inorganic filler is surface-treated with a coupling agent, the rubber component and the inorganic filler are chemically bonded as well as physically bonded through pores on the surface of the inorganic filler. Thus, a stronger adhesive force can be obtained, and the problem of the inorganic filler detaching from the rubber matrix can be significantly improved.

The coupling agent is not particularly limited and can be appropriately selected according to the purpose. For example, a silane coupling agent represented by DEG69SA Si69 is preferable. Examples of the silane coupling agent include bis (3-triethoxysilylpropyl) tetrasulfide, bis (2-triethoxysilylethyl) tetrasulfide, bis (3-trimethoxysilylpropyl) tetrasulfide, and bis (2- Trimethoxysilylethyl) tetrasulfide, 3-mercaptopropyltrimethoxysilane, 3-mercaptopropyltriethoxysilane, 2-mercaptoethyltrimethoxysilane, 3-nitropropyltrimethoxysilane, 3
-Nitropropyltriethoxysilane, 3-chloropropyltrimethoxysilane, 3-chloropropyltriethoxysilane, 2-chloroethyltrimethoxysilane,
-Chloroethyltriethoxysilane, 3-trimethoxysilylpropyl-N, N-dimethylthiocarbamoyltetrasulfide, 3-triethoxysilylpropyl-
N, N-dimethylthiocarbamoyltetrasulfide,
2-triethoxysilylethyl-N, N-dimethylthiocarbamoyl tetrasulfide, 3-trimethoxysilylpropyl benzothiazole tetrasulfide, 3-triethoxysilylpropyl benzothiazole tetrasulfide, 3-triethoxysilylpropyl methacrylate monosulfide, 3 -Trimethoxysilylpropyl methacrylate monosulfide. These may be used alone or in combination of two or more. Among these, bis (3-triethoxysilylpropyl) tetrasulfide, 3-trimethoxysilylpropylbenzothiazole tetrasulfide and the like are preferable.

The content of the coupling agent in the rubber composition is 5 to 2 parts by weight based on the weight of the inorganic filler.
It is preferably 5% by weight, more preferably 10 to 25% by weight. When the content of the coupling agent in the rubber composition is less than 5% by weight based on the weight of the inorganic filler, the dispersibility improving effect and the reinforcing effect of the inorganic filler in the rubber component are sufficient. On the other hand, the on-ice performance and abrasion resistance of the vulcanized rubber obtained by vulcanizing the rubber composition may not be sufficiently improved. On the other hand, if it exceeds 25% by weight, the effect corresponding thereto cannot be obtained. There is.

In the present invention, the inorganic filler is preferably subjected to a surface treatment capable of improving the affinity with the rubber component. When the inorganic filler has been subjected to such a surface treatment, when a vulcanized rubber obtained by vulcanizing the rubber composition is used for a tread of a tire, the inorganic filler is used during running. This is advantageous in that it is difficult to separate from the matrix and the abrasion resistance of the tread and the like can be improved.

--Long Body-- In the present invention, as the long body, short fibers and a long resin which will be described later are particularly preferably exemplified. In the present invention, as the long body, only the short fiber or the long resin may be used, or the short fiber and the long resin may be used in combination.

The denier of the elongated body is not particularly limited and can be appropriately selected according to the purpose.
From the viewpoint of improving the performance on ice, 1 to 1000 denier is preferable, and 2 to 800 is more preferable.

The average length (L) of the elongated body is as follows:
There is no particular limitation, and it can be appropriately selected according to the purpose. However, a viewpoint of improving the performance on ice of the tire when the vulcanized rubber obtained by vulcanizing the rubber composition is used for a tread or the like in the tire. From this, at least 500 μm (that is, 500 μm or more) is preferable, and 500 to 5000 μm
m is more preferred. The average length (L) is 500 μm
If it is less than 3, the orientation of the elongated body in the rubber composition may not be sufficient. In addition, the average length (L) of the said elongated body means the average value of the length of the used elongated body.

The average diameter (D) of the elongated body is not particularly limited and may be appropriately selected depending on the intended purpose. From the viewpoint of improving the on-ice performance of the tire, the average diameter (D) is 30 to 500.
μm is preferred, and 50 to 200 μm is more preferred. If the average diameter (D) is less than 30 μm, the vulcanized rubber obtained by vulcanizing the rubber composition does not have a sufficient water exclusion function,
If the performance on ice is not improved, and if it exceeds 500 μm, the durability, cut resistance and abrasion resistance of the vulcanized rubber are undesirably reduced. The average diameter (D) of the elongated body can be calculated by, for example, observing with a microscope.

The ratio (L / D) between the average length (L) and the average diameter (D) of the elongated body is at least 3.0.
(3.0 or more) is preferable, and 5 to 100 is more preferable. When the ratio (L / D) is less than 3.0, sufficient orientation cannot be obtained after extrusion, sufficient ice and snow performance cannot be obtained, and vulcanization obtained by vulcanizing the rubber composition can be obtained. It is not preferable in that the abrasion resistance of rubber deteriorates.

—Short Fibers— The short fibers can be selected from, for example, organic synthetic fibers, regenerated fibers and natural fibers. The short fibers do not soften or melt during vulcanization of the rubber composition. Examples of the organic synthetic fibers include nylon, polyester, Kevlar, and aramid. Examples of the recycled fiber include rayon and cupra. Examples of the natural fibers include cotton, silk, wool, and the like. In the present invention, among these, nylon and polyester are preferable in that heat shrinkage is easily controlled. These staple fibers may be used alone or may be used alone.
More than one species may be used in combination.

The heat shrinkage of the short fibers at the vulcanization temperature of the rubber composition is preferably 8% or less, more preferably 4% or less, and more preferably 2% or less. Particularly preferred. If the heat shrinkage exceeds 8%, the short fibers shrink during vulcanization, and the desired orientation cannot be obtained in the rubber matrix. In this case, the vulcanized rubber is used for a tread of a tire or the like. Even then, performance on ice may be degraded. In order to control the heat shrinkage of the short fiber to 8% or less, it is preferable to perform a drawing step or the like at the time of spinning or obtaining the short fiber at a temperature higher than the vulcanization temperature of the rubber composition (in this case, , The stretching tension and the stretching ratio are more effective when both are reduced).

-Long Resin- The long resin has a viscosity at which the rubber matrix containing the long resin reaches the maximum vulcanization temperature during vulcanization. It is necessary to have a property that the viscosity is lower than the viscosity. The maximum vulcanization temperature means the maximum temperature reached by the rubber composition at the time of vulcanization of the rubber composition containing the long resin. For example,
In the case of mold vulcanization, it means the maximum temperature at which the rubber composition reaches from the time when the rubber composition enters the mold to the time when the rubber composition leaves the mold and is cooled. The vulcanization maximum temperature is
For example, it can be measured by embedding a thermocouple in the rubber composition. The viscosity of the rubber matrix means a flow viscosity, which can be measured using, for example, a cone rheometer, a capillary rheometer, or the like. The viscosity of the long resin means a melt viscosity, which can be measured using, for example, a cone rheometer, a capillary rheometer, or the like.

The material of the long resin is not particularly limited as long as it has the above-mentioned thermal characteristics, and can be appropriately selected according to the purpose. For example, a long resin made of a crystalline polymer having a melting point lower than the maximum vulcanization temperature is preferably used.

The resin composed of the crystalline polymer will be described as an example. As the difference between the melting point and the maximum vulcanization temperature of the rubber composition containing the long resin increases, the vulcanization during vulcanization increases. Since the elongated resin is quickly melted, the time at which the viscosity of the elongated resin portion becomes lower than the viscosity of the rubber matrix is earlier, and the gas generated from the foaming agent after the elongated resin is melted. Etc. migrate into the elongated resin having a lower viscosity than the rubber matrix. As a result, there are many long bubbles in the vulcanized rubber whose inner wall is covered with the long resin.

On the other hand, if the melting point of the elongated resin becomes too close to the maximum vulcanization temperature of the rubber composition containing the elongated resin, the elongated resin melts immediately at the beginning of vulcanization. Without this, the long resin melts at the end of vulcanization. In the final stage of vulcanization, the gas generated from the foaming agent has been taken into the crosslinked rubber matrix, so that the gas is not sufficiently retained in the molten long resin. On the other hand, when the melting point of the long resin is too low, the resin is melted by heat during kneading of the rubber composition, and poor dispersion due to fusion of the long resins during kneading, At the kneading stage, the long resin is broken into a plurality of pieces, and the long resin melts into the rubber composition and is microscopically dispersed.

Therefore, the melting point of the long resin is preferably selected in consideration of the above points.
The melting point of the long resin is preferably lower than the highest vulcanization temperature of the rubber composition containing the resin by 10 ° C. or more, more preferably 20 ° C. or more. The industrial vulcanization temperature of rubber compositions is generally up to about 190
℃, for example, the maximum vulcanization temperature is 190 ℃
When it is set to, the melting point of the long resin is usually selected at 190 ° C or lower, preferably 180 ° C or lower, more preferably 170 ° C or lower.

On the other hand, considering the kneading of the rubber composition,
The melting point of the long resin is preferably 5 ° C. or higher, more preferably 10 ° C. or higher, and particularly preferably 20 ° C. or higher, relative to the maximum temperature during kneading. Assuming that the maximum temperature during kneading of the rubber composition is, for example, 95 ° C., the melting point of the long resin is preferably 100 ° C. or more,
It is more preferably at least 05 ° C, particularly preferably at least 115 ° C. In the present invention, the melting point can be measured using a melting point measuring apparatus known per se, for example, a DSC measuring apparatus (for example, 910 manufactured by DuPont, USA).
(Heating rate 10 ° C / min, sample weight 5m)
The melting peak temperature obtained under the condition (g) can be used as the melting point.

In the present invention, it is preferable that the long resin has a property of softening at a temperature not higher than the extrusion temperature of the rubber composition. This is advantageous in that the control of the orientation of the long resin is easy.

The elongated resin may be formed from a crystalline polymer, may be formed from a non-crystalline polymer, or may be formed from a crystalline polymer and a non-crystalline polymer. Although it may be, in the present invention, it is preferably formed from an organic material containing a crystalline polymer in that the viscosity change occurs abruptly at a certain temperature due to a phase transition, and viscosity control is easy. It is more preferably formed from a crystalline polymer.

Specific examples of the crystalline polymer include, for example, polyethylene (PE), polypropylene (PP),
Mono-component polymers such as polybutylene, polybutylene succinate, polyethylene succinate, syndiotactic-1,2-polybutadiene (SPB), copolymerization,
A resin whose melting point is adjusted to an appropriate range by blending or the like can be used, and an additive may be added to these long resins. Among these crystalline polymers, polyolefins and polyolefin copolymers are preferred, and polyethylene and polypropylene are more preferred because they are widely available.

Examples of the non-crystalline polymer include polymethyl methacrylate, acrylonitrile butadiene styrene copolymer (ABS), polystyrene, polyethylene NR, SPB, PMMA, PAN, copolymers thereof, and blends thereof. And the like.

If necessary, known additives may be added to the long resin as long as the object of the present invention is not impaired.

The molecular weight of the organic material in the long resin varies depending on the chemical composition of the organic material, the state of branching of the molecular chains, and cannot be specified unconditionally. There are no special restrictions. In general, even if the long resin is formed of the same organic material, the higher the molecular weight, the higher the viscosity (melt viscosity) at a certain temperature. Therefore, in the present invention, the molecular weight of the organic material in the long resin is larger than the viscosity (flow viscosity) of the rubber composition containing the long resin at the maximum vulcanization temperature of the rubber composition. It is selected in a range that does not increase the viscosity (melt viscosity) of the long resin.

In one test example, the lengthy resin was 1 to
In the case of polyethylene having a weight-average molecular weight of about 2 × 10 ^5, the gas generated from the blowing agent is more likely to be present inside the long resin after vulcanization than in the case of polyethylene having a weight-average molecular weight of 7 × 10 ⁵ or more. In large amounts. The difference is
It is presumed to be based on the difference in viscosity (melt viscosity) due to the difference in the molecular weight of polyethylene, which is the material of the long resin. On the other hand, if the molecular weight of the organic material in the long resin is too low, the viscosity (melt viscosity) of the long resin decreases at the stage of kneading the rubber composition containing the long resin. This is not preferable because fusion of the long resins occurs and dispersibility of the long resins in the rubber composition deteriorates.

-Content of the elongated body-The content of the elongated body in the rubber composition is 1 to 100 parts by weight of the rubber matrix.
It is necessary to be 20 parts by weight, preferably 3 to 15 parts by weight, more preferably 5 to 10 parts by weight. Further, in the present invention, as the content in the rubber composition of the elongated body, the lower limit or the upper limit of any of the numerical range or the value of the content adopted in the examples described below, the lower limit, A numerical range in which the lower limit or upper limit of any of the above numerical ranges or the value of the content employed in the examples described below is the upper limit is also preferable.

When the content is less than 1 part by weight, when the elongated body is the elongated resin, the rubber composition is added to the elongated resin blended in the rubber composition. The amount of gas taken up or retained in an object may increase, and the average diameter (D) of the long bubbles may become too large. The number of short fibers cannot be secured, and the formation of drainage grooves may be insufficient.In each case, vulcanized rubber obtained by vulcanizing the rubber composition is used for a tread or the like of a tire. However, the performance on ice cannot be sufficiently improved. On the other hand, when the content exceeds 20 parts by weight, when the elongated body is the elongated resin, the dispersibility of the elongated resin in the rubber composition is deteriorated. Workability at the time deteriorates, inconveniences such as the occurrence of cracks in the tread and the like may occur, and when the long body is the short fiber, there is the inconvenience as described above. The vulcanized rubber becomes too hard, and the performance on ice may be reduced. It is preferable that the content is within the above-mentioned preferable numerical range, since productivity, abrasion resistance, durability, cut resistance and performance on ice are maintained in a well-balanced and high level without such occurrence.

-Preparation of Rubber Composition- The rubber composition of the present invention is adjusted by appropriately kneading the above components, heating, extruding, and the like. The elongated body in the composition is oriented in a direction substantially parallel to the extrusion direction.

The kneading conditions include various conditions such as the volume to be charged into the kneading apparatus, the rotation speed of the rotor, the ram pressure, the kneading temperature, the kneading time, and the type of the kneading apparatus, depending on the purpose. It can be selected as appropriate. As the kneading device, a commercially available product can be suitably used. Examples of such a commercially available product include a Banbury mixer, an intermix, and a kneader that are usually used for kneading a rubber composition for a tire. .

The heating conditions include a heating temperature,
Various conditions such as a heating time and a heating device can be appropriately selected according to the purpose. As the warming device, a commercially available product can be suitably used. As such a commercially available product, for example, a roll machine usually used for warming a rubber composition for a tire can be used.

As the conditions for the extrusion, various conditions such as an extrusion time, an extrusion speed, and an extrusion apparatus can be appropriately selected according to the purpose. As the extruder, a commercially available product can be suitably used, and such a commercially available product includes, for example, an extruder or the like usually used for extruding a rubber composition for a tire. In addition, the extrusion temperature can be appropriately determined according to the melting point of the elongated body, the foaming start temperature of the foaming agent, and the like.

In the rubber composition of the present invention, as a result of the extrusion, the phases of the elongated body are arranged in a direction substantially parallel to the extrusion direction. In order to achieve this effectively, What is necessary is just to control the fluidity of the rubber matrix within a limited temperature range, and specifically, in the rubber matrix, an aroma oil, a naphthene oil, a paraffin oil, a plasticizer such as an ester oil, etc. By appropriately adding a processability improver such as a liquid polymer such as liquid polyisoprene rubber and liquid polybutadiene rubber to lower the viscosity of the rubber matrix and increase its fluidity, it is possible to extrude very well. And ideally, the phase of the long resin can be arranged substantially parallel to the extrusion direction.

In the rubber composition, when the phases of the elongated body are arranged substantially parallel to the extrusion direction, the vulcanized rubber obtained by vulcanizing the rubber composition is used for a tread of a tire or the like. Then, in detail, when used in a state in which the phase of the elongated body is oriented in a direction parallel to the surface of the tread or the like that comes into contact with the ground, more preferably in the circumferential direction of the tire, the running direction of the tire is It is preferable in that the drainage property is enhanced and the performance on ice can be improved.

In order to orient the phase of the elongated body in a predetermined direction in the rubber composition, a known method can be employed. For example, as shown in FIG. Fifteen
And a method of extruding a rubber matrix 16 kneaded with an extruder 17 having a channel cross-sectional area decreasing toward an outlet. In this case, the elongated body 15 in the rubber matrix 16 before being extruded gradually aligns in the extrusion direction (the direction of the arrow B) in the process of being extruded into the die 17, so that the die is formed. When it is extruded from 17, its longitudinal direction is almost completely aligned with the extrusion direction (arrow B direction). In this case, the degree of orientation of the elongated body 15 in the rubber matrix 16 is as follows.
It varies depending on the degree of decrease in the flow path cross-sectional area, the extrusion speed, the viscosity of the rubber matrix, and the like.

In order to orient the phase of the elongated body in a predetermined direction in the rubber composition, a discharging speed (V ₁ ) of the rubber composition from the extruder and a pulling speed (V) from the train after the discharging.
₂₎ the ratio of (V ₂ / V ₁₎ is of the formula (3) :( V ₂ /
V ₁ ) ≧ 1.03 is preferably satisfied. In order to reduce the residual stress after extrusion and improve the storage stability (shrinkage) of the shape, the ratio (V ₂ / V ₁ ) ≒ 1.
It is preferable that the discharge speed and the withdrawal speed are equal to each other. However, in the present invention, since the high-structure carbon satisfying the formulas (1) and (2) is used, the shape can be stably stored. Since the property (shrinkage property) can be appropriately suppressed, it is sufficient to satisfy the above expression (3).

When the elongated body is the elongated resin, the relationship between the average length (L) and the average diameter (D) of the phases of the elongated body is inversely related. Yes, it can be adjusted by appropriately changing the extrusion temperature and the extrusion speed. That is, by setting the extrusion temperature significantly higher than the melting point of the elongated resin, the viscosity of the phase of the elongated resin is lowered, and the average diameter of the phase of the elongated resin is increased by increasing the extrusion speed. (D) can be made smaller (thinner) and the average length (L) can be made longer, and the ratio (L / D) of the average length (L) and the average diameter (D) of the phase of the elongated resin can be obtained. ) Can be large.

Therefore, when the elongated body is the elongated resin, the length of the phase of the elongated body (average length (L) and average diameter (D)) is determined according to the desired size. Extrusion temperature,
It is necessary to set the kneading conditions such as the extrusion speed, the initial dispersion particle size, and the kneading maximum temperature and the number of times associated with it, but by appropriately changing these conditions,
It is a small diameter and the ratio (L) of the average length (L) and the average diameter (D)
/ D) from a phase of a long resin having a small diameter to a phase of a long body having a large diameter and a large ratio (L / D) of the average length (L) to the average diameter (D). be able to.

When the elongated body is the elongated resin, in the rubber composition containing the elongated resin, the viscosity of the elongated resin before vulcanization is higher than that of the rubber matrix. Is getting higher. After the start of vulcanization and before the rubber composition reaches the maximum vulcanization temperature, the viscosity of the rubber matrix contained in the rubber composition increases by vulcanization.
On the other hand, the viscosity of the long resin contained in the rubber composition is greatly reduced by melting. During the vulcanization, the viscosity of the long resin becomes lower than that of the rubber matrix. That is, there occurs a phenomenon in which the viscosity relationship between the rubber matrix before vulcanization and the long resin is reversed in the middle of vulcanization. During this time, in the rubber composition,
When a blowing agent is used, efficient foaming by the blowing agent occurs, and gas is generated. The gas generated by the foaming moves into the melted elongated resin whose viscosity is relatively lower than that of the rubber matrix whose viscosity has increased due to the progress of the vulcanization reaction, and is easily taken in.

As a result, in the vulcanized rubber after vulcanization of the rubber composition, long bubbles exist in the rubber composition where the long resin was present. The long bubbles have a periphery facing the long bubbles (walls defining the long bubbles) covered with the long resin material, and are independently formed in the vulcanized rubber. Existing. When the material of the long resin is polyethylene, polypropylene or the like, the vulcanized rubber matrix and the coating layer (hereinafter sometimes referred to as “protective layer”) made of the material of the long resin are strong. Glued to. When the foaming agent is used, a vulcanized rubber having a high foaming rate is obtained.

Incidentally, in the vulcanized rubber obtained by vulcanizing the rubber composition of the present invention, the adhesive force between the elongated body and the vulcanized rubber matrix is determined before the vulcanized rubber is vulcanized. It can be arbitrarily adjusted by adding an appropriately selected additive to the above rubber composition. The adhesive force is preferably larger when the elongated body is the elongated resin, and is preferably smaller when the elongated body is the short fiber. In the latter case, when the vulcanized rubber is used for, for example, a tread of a tire, the short fibers exposed on the surface that comes into contact with the ground are easily dropped off by friction with the ground, and the short fibers are exposed on the surface. This is advantageous in that a long groove formed by dropping can be easily obtained. This long groove can exert a water film removing ability and an edge effect in the tire.

Although the rubber composition of the present invention can be suitably used in various fields, it can be particularly preferably used as a raw material of a vulcanized rubber of the present invention described later.

(Vulcanized Rubber) The vulcanized rubber of the present invention can be easily obtained by vulcanizing the rubber composition of the present invention. When the vulcanized rubber of the present invention is used for a tread or the like of a tire described below, before vulcanization, the elongated body in the rubber composition of the present invention as a raw material is oriented in a predetermined direction. Is preferred. Specifically, when the elongated body is oriented in a direction parallel to the surface of the tread that contacts the ground, and further along the circumferential direction of the tire, the vulcanized rubber has the elongated shape. When the body is the long resin, the long bubbles exist in a state where the long resin is oriented in the place where the long resin was present, and when the long body is the short fiber, The short fibers exist in an oriented state. As a result, when the vulcanized rubber is used for a tread or the like of a tire, a long drain groove formed by detachment of the short fibers during running, or a fine drain groove due to the long bubble is formed in the tire. Exposed on the surface, the drainage groove exhibits a water film removing ability and an edge effect, so that drainage in the running direction of the tire is enhanced, and performance on ice is improved.

In order to orient the elongated body in a predetermined direction in the rubber composition, a known method can be adopted. For example, as shown in FIG. A method in which the kneaded rubber matrix 16 is extruded from a die 17 of an extruder in which the cross-sectional area of the flow channel decreases toward the outlet is exemplified. In this case, the elongated body 15 in the rubber matrix 16 before being extruded gradually aligns in the extrusion direction (the direction of the arrow B) in the process of being extruded into the die 17, so that the die is formed. When it is extruded from 17, its longitudinal direction is almost completely aligned with the extrusion direction (arrow B direction). In this case, the degree of orientation of the elongated body 15 in the rubber matrix 16 is as follows.
It varies depending on the degree of decrease in the flow path cross-sectional area, the extrusion speed, the viscosity of the rubber matrix, and the like.

There are no particular restrictions on the apparatus or system for performing the vulcanization, and it can be appropriately selected according to the purpose. Specific examples of the vulcanizing apparatus include, for example, a molding vulcanizer using a mold usually used for vulcanizing a rubber composition for a tire.

In the vulcanized rubber according to the present invention, when the long body is the short fiber in the vulcanized rubber matrix, the short fiber is used as it is and the long body is the long body. In the case of a resin, there are elongated bubbles in which the elongated resin is melted and gas is contained therein. When the elongated body in the rubber composition is oriented in one direction by extruding the rubber composition of the present invention as a raw material, in the case of vulcanized rubber, the elongated body is In the case of the short fibers, the short fibers are contained in a state oriented in the extrusion direction. When the long body is the long resin, as shown in FIG. Long bubble 1
2 exist in a state oriented in the extrusion direction (A direction in FIG. 3). The long bubbles 12 are surrounded by a protective layer 14 formed by bonding a molten long resin to a vulcanized rubber matrix. Therefore, the long bubble 12
Exists as an independent space in the vulcanized rubber, and gas or the like generated from a foaming agent is taken into the elongated bubbles 12.

As shown in FIG. 3, the gas generated from the foaming agent is present as spherical bubbles 18 in the vulcanized rubber matrix. In the case where is the long resin, it means gas which is not taken into the molten resin when the long resin is melted). When the vulcanized rubber of the present invention is used in, for example, a tread of a tire, etc., the elongated bubbles 12 exposed on the surface thereof and the elongated grooves formed by dropping the elongated bodies of short fibers are formed. Or spherical bubbles 18
However, it functions as a discharge path for efficiently discharging water. Since the protective layer 14 having excellent peeling resistance is present around the long bubbles 12, the vulcanized rubber of the present invention having the long bubbles 12 has a water channel shape retention property and a water channel edge wear. In particular, it is particularly excellent in water resistance and water channel retention at the time of load input.

In the vulcanized rubber according to the present invention, when the elongated body is the short fiber, the elongated body is formed in the elongated groove formed by dropping the short fiber. In the case of a long resin, the average length (L) (see FIG. 3) and the average diameter (D) of each long bubble 12 obtained by changing the long resin are used. And the ratio (L /
D) needs to be at least 3 (ie, 3 or more), and at least 5 (ie, 5 or more) is preferable.
The upper limit of the ratio (L / D) is not particularly limited,
About 100 are selected. Further, in the present invention, the lower limit or upper limit of any of the above numerical ranges or the value of the ratio (L / D) employed in Examples described later is used as the lower limit as the ratio (L / D). A numerical range in which the lower limit or upper limit of any of the numerical ranges or the ratio (L / D) employed in the examples described below is the upper limit is also preferable.

If the ratio (L / D) is less than 3, the length of the elongated groove or the elongated bubble 12 appearing on the surface of the worn vulcanized rubber cannot be increased, and the volume Therefore, when the vulcanized rubber is used for a tread or the like of a tire, it is not preferable because the water removal performance of the tire or the like cannot be improved.

In the vulcanized rubber composition of the present invention, the average length (L) of the elongated grooves or elongated bubbles 12 (= the major axis of the protective layer 14; see FIG. 3) is 500 to 5000.
mm is preferred. When the average length (L) is less than 500 mm, when the vulcanized rubber is used for a tread or the like of a tire, the water drainage performance of the tire is reduced, and the
If it exceeds m, the cut resistance and the chipping of the block of the vulcanized rubber deteriorate, and the abrasion resistance on a dry road surface deteriorates.

In the vulcanized rubber of the present invention, the average diameter (D) of the long grooves or long bubbles 12 (= the inner diameter of the protective layer 14, see FIG. 3) is preferably 30 to 500 μm. When the average diameter (D) is less than 30 μm, when the vulcanized rubber is used for a tread or the like of a tire, the water drainage performance of the tire is reduced. Both of these are not preferable because the cut property and the chipping of the block are deteriorated, and the wear resistance on a dry road surface is deteriorated.

The average foaming ratio Vs in the vulcanized rubber of the present invention
From the viewpoint of ice and snow performance and wear resistance,
Is preferable, and 5 to 35% is more preferable. Further, in the present invention, as the average foaming rate Vs, a lower limit or an upper limit of any of the numerical ranges or a value of the average foaming rate Vs in Examples described later is a lower limit, and a lower limit of any of the numerical ranges is set. A value or an upper limit value or a numerical range in which the value of the average foaming rate Vs in Examples described later is an upper limit is also preferable.

The above average foaming rate is defined as Vs,
The expansion ratio Vs1 of 8 and the expansion ratio Vs2 of the long bubbles 12 mean the sum, and can be calculated by the following equation. Vs = (ρ ₀ / ρ ₁ −1) × 100 (%) Here, ρ ₁ is the density (g / c) of the vulcanized rubber (foamed rubber).
m ³ ). ρ ₀ represents the density (g / cm ³ ) of the solid phase portion in the vulcanized rubber (foamed rubber). The density of the vulcanized rubber (foamed rubber) and the density of the solid phase portion in the vulcanized rubber (foamed rubber) were calculated from, for example, the weight in ethanol and the weight in air.

When the average foaming ratio Vs is less than 3%, a sufficient water exclusion function cannot be obtained due to a lack of absolute concave volume with respect to a generated water film, and an improvement in performance on ice cannot be expected. On the other hand, if it exceeds 40%, the effect of improving performance on ice is sufficient, but the number of air bubbles in the vulcanized rubber becomes too large, so that the breaking limit of the compound is greatly reduced, which is not preferable in terms of durability. The average foaming ratio Vs can be appropriately changed depending on the type and amount of the foaming agent, the type and amount of the foaming auxiliary to be combined, the amount of the resin blended, and the like.

When the elongated body is the elongated resin, the average foaming rate Vs is 3 to 40% and the elongated bubbles are at least 10% of the average foaming rate Vs. It is preferable to occupy If the ratio is less than 10%, there are few suitable drainage channels for the long bubbles, and the water removal function may not be sufficient. Also,
When the elongated body is the elongated resin,
The elongated bubbles 12 in the vulcanized rubber form a protective layer 14 formed by bonding the molten elongated resin to a vulcanized rubber matrix.
The thickness of the protective layer 14 is
It is preferably at most 50 μm (50 μm or less). If the thickness exceeds 50 μm, the vulcanized rubber becomes too hard, and the performance on ice may be rather deteriorated.

Although the vulcanized rubber of the present invention can be suitably used in various fields, it can be particularly suitably used for a structure that needs to suppress slip on ice, and is most suitably used for a tread of a tire and the like. Can be used. Examples of the structure required to suppress the slip on the ice include a tread for replacing a retreaded tire, a solid tire, a contact portion of a rubber tire chain used for running on an icy road, a crawler of a snowmobile, and shoes. Bottom, belt, caster and the like.

(Tire) The tire of the present invention has at least a tread, and other structures are not particularly limited as long as at least the tread contains the vulcanized rubber of the present invention. You can choose. In other words, the tire in which the tread is formed by using the rubber composition of the present invention and vulcanizing the same is the tire of the present invention.

An example of the tire of the present invention will be described below with reference to the drawings. The following example is an example in which a vulcanized rubber obtained by vulcanizing a rubber composition in which the elongated body is the elongated resin is used for a tread of a tire (pneumatic tire). is there. Even when a vulcanized rubber obtained by vulcanizing a rubber composition in which the long body is the short fiber is used, basically the same operation and effect as in the above example are exhibited. That is, in this case, the long grooves formed by the short fibers falling off during running exhibit the same action or effect as the long bubbles in the above example.

As shown in FIG. 4, a tire (size: 185 / 70R14) 4 of the present invention has a pair of bead portions 1 and
The carcass 2 has a radial structure in which a carcass 2 connected to the pair of beads 1 in a toroidal shape, a belt 3 for clinching a crown portion of the carcass 2, and a tread 5 are sequentially arranged. Note that the internal structure other than the tread 5 is not different from the structure of a general radial tire, and therefore the description is omitted.

As shown in FIG. 5, a plurality of blocks 10 are formed in the tread 5 by a plurality of circumferential grooves 8 and a plurality of transverse grooves 9 intersecting the circumferential grooves 8. Further, the block 10 is formed with a sipe 11 extending along the tire width direction (the X direction in FIG. 5) in order to improve braking performance and traction performance on ice.

As shown in FIG. 6, the tread 5 has an upper cap portion 6 directly in contact with the road surface,
Lower base portion 7 disposed adjacent to the tire inside
And a so-called cap-base structure.

As shown in FIGS. 3 and 8, the cap portion 6 is a foamed rubber containing a myriad of spherical bubbles 18 and elongated bubbles 12, and the base portion 7 is not foamed. Rubber is used. This foamed rubber is the vulcanized rubber of the present invention. As shown in FIG. 3, the long bubbles 12 are oriented in the longitudinal direction substantially in the tire circumferential direction (the direction of arrow A in FIGS. 3, 6, and 8 and the direction of Y in FIG. 5). The periphery is reinforced by a protective layer 14 made of a long resin.

The method of manufacturing the tire 4 is not particularly limited. For example, the tire 4 can be manufactured as follows.

As the at least one rubber component selected from natural rubber and diene-based synthetic rubber in the rubber composition of the present invention for forming the cap portion 6, a rubber component having a glass transition temperature of -60 ° C. or less is preferable. . The glass transition temperature is such that the cap portion 6 of the tread 5
This is for maintaining sufficient rubber elasticity in a low temperature range and obtaining sufficient performance on ice. When kneading the rubber composition, the resin is kneaded in the rubber matrix and is uniformly dispersed. The resin is more viscous (melt viscosity) than the viscosity (flow viscosity) of the rubber matrix until the temperature of the rubber composition reaches the maximum vulcanization temperature in the tire vulcanization step.
Is formed of a material having a low density.

As shown in FIG. 2, when the rubber matrix 16 kneaded with the long resin 15 is extruded from the base 17 of the extruder whose cross-sectional area of the flow path decreases toward the outlet, the long resin 15 , Ie, the longitudinal direction of the long resin 15 is gradually aligned along the extrusion direction (arrow B direction).
7, since the longitudinal direction of the long resin 15 is aligned with the extrusion direction, the strip-shaped rubber composition extruded from the base 17 is cut into a desired length, and this is used as the rubber of the cap portion 6. be able to.

The unvulcanized cap portion 6 made of the rubber composition thus obtained is attached to the unvulcanized base portion 7 previously attached to the crown portion of the unvulcanized tire case.
(See FIG. 6), the tire 4 can be manufactured by pasting so that the longitudinal direction thereof coincides with the tire circumferential direction and vulcanizing and molding at a predetermined temperature and a predetermined pressure with a predetermined mold. it can.

At this time, when the unvulcanized cap portion 6 is heated in the mold, foaming by the foaming agent occurs in the rubber matrix, and gas is generated. On the other hand, the long resin melts (or softens) and its viscosity (melt viscosity) becomes lower than the viscosity (flow viscosity) of the rubber matrix (see FIG. 7). The gas generated by the foaming by the foaming agent moves into the melted elongated resin. As shown in FIG.
Is a rubber having a high foaming ratio in which spherical bubbles 18 and long bubbles 12 are present. The rubber having a high foaming rate is the vulcanized rubber of the present invention.

Next, the operation of the tire 4 will be described.
That is, when the tire 4 is run, as shown in FIG. 8, the concave portion 19 formed by the spherical bubble 18 and the groove-shaped concave portion 13 formed by the long bubble 12 form the cap portion of the tread 5 at a very early stage of wear. 6 appears on the ground plane. When the tire 4 is run on ice in this state, a water film is formed between the tire 4 and the ice surface due to the contact pressure and frictional heat, but the countless recesses 13 formed on the contact surface of the cap portion 6 of the tread 5 are formed. The water (water film) in the ground plane is quickly eliminated and removed by the concave portion 19.

In the tire 4, the elongated (groove-shaped) concave portion 13 whose longitudinal direction is substantially the tire circumferential direction functions as a drainage channel for discharging water efficiently, and the elongated The (groove-shaped) concave portion 13 improves the performance of removing water to the rear side in the tire rotation direction on the ground contact surface, and particularly improves the braking performance on ice. The long (groove) concave portion 1
No. 3 is made of a material whose periphery is harder than the rubber matrix and has excellent peeling resistance because it is reinforced with a protective layer 14 having excellent peeling resistance. Rejection performance is always maintained. Further, in the tire 4, since the scratching effect is generated by the protective layer 14 exposed on the ground contact surface, the scratching effect improves the μ on the ice in the lateral direction and improves the handling on the ice.

The tread 5 of the tire 4 is formed by the vulcanized rubber of the present invention or by using the rubber composition of the present invention and vulcanizing the same. The volume ratio of the long bubbles 12 is higher than that of the spherical bubbles 18. Therefore, during the running of the tire 4, the long bubbles 12 (when the long body is the short fiber, or when the long body includes not only the long resin but also the short fiber) It is highly probable that the recesses 13 formed by the elongated grooves formed by dropping the short fibers are exposed on the surface of the tire 4, and as a result, the water removal function by the recesses 13 is improved as a whole, Performance on ice is improved.

In the tire 4, the long bubbles 1
2 (When the long body is the short fiber, or when the long body includes not only the long resin but also the short fiber, the length formed by dropping the short fiber is used. The longitudinal directions of the recesses 13 formed by the long grooves may not all be in the tire circumferential direction, and may be partially different from the tire circumferential direction (see FIG. 6).

The tire of the present invention can be suitably applied not only to so-called passenger cars but also to various vehicles such as trucks and buses.

[0097]

EXAMPLES Examples of the present invention will be described below, but the present invention is not limited to these examples.

(Examples 1 to 7 and Comparative Examples 1 to 10) Table 1
And Table 2 shows the rubber composition extruder composition (extrusion _{conditions: (V 2 / V 1)} = 1.04) extruded prepared in,
Each of the rubber compositions is vulcanized to convert the tread into a vulcanized rubber.
Four sizes of studless tires (pneumatic tires) for passenger cars were manufactured. In this tire, the tread is formed of vulcanized rubber.

The structure of the tire is as shown in FIG. That is, a pair of bead portions 1, a carcass 2 connected to the pair of bead portions 1 in a toroidal shape,
Has a radial structure in which a belt 3 for clasping the crown portion and a tread 5 are sequentially arranged.

In the tire 4, the carcass 2 is arranged at an angle of 90 ° with respect to the tire circumferential direction, and the number of cords driven is 50/5 cm. Tread 5 of tire 4
, Four blocks 10 are arranged in the tire width direction as shown in FIG. The size of the block 10 is 35 mm in the tire circumferential direction and 30 mm in the tire width direction. The sipe 11 formed in the block 10 has a width of 0.4 mm and an interval in the tire circumferential direction of about 7 mm. The tread 5 of the tire 4 includes an elongated bubble 12, and its longitudinal direction substantially corresponds to the circumferential direction of the tire (the direction of arrow A in FIGS. 3, 6, and 8; (Y direction), and the periphery thereof is reinforced by a protective layer 14 made of a long resin.

The foaming ratio of the tread of the obtained tire 4 was
It was determined as follows. That is, a block-shaped sample is cut out from the tread of each tire, and the density ρ ₁ (g / m ³ ) of the block-shaped sample is measured. On the other hand, the density ρ ₀ of the non-foamed rubber (solid rubber) is measured. Then, equation (4): was calculated by foaming ratio _{= (ρ 0 / ρ 1 -1} ) × 100 (%).

The performance on ice and the abrasion resistance of each tire were evaluated as follows. The results are shown in Tables 1 and 2. <Performance on ice> Each tire is domestically produced 2000cc class FF
After being mounted on the car, the FF car was run-in (1000 km) on a smooth dry road surface (on a test course), and then was run on a flat road on ice (ice temperature -1 ° C) at a speed of 20 km / h. The brake was depressed to lock the tire, and the distance to the stop was measured. The result is the reciprocal of the distance.
The braking distance of the tire of No. was expressed as an index with 100. The higher the value, the better the performance on ice. <Abrasion resistance> The same tires and vehicles as those used for the evaluation of the above-mentioned performance on ice were used for 10,000 km each in a general urban area in Japan.
It was determined from the depth of the remaining groove after traveling m. The index of the tire of Comparative Example 1 was set to 100 and indexed. That is, the larger the numerical value, the better the wear resistance.

[0103]

[Table 1]

[0104]

[Table 2]

In Table 1, "DBP" and "N
₂ SA "are as described above. The cis-1,4-polybutadiene is BR01 manufactured by JSR Corporation. "Anti-aging agent" is N- (1,3-dimethylbutyl) -N-phenyl-p-phenylenediamine. `` Vulcanization accelerator ''
Is N-cyclohexyl-2-benzothiazyl-1-sulfenamide. “Blowing agent” is dinitropentamethylenetetramine (Cellular D, manufactured by Eiwa Chemical Industry Co., Ltd.). The “foaming aid” is urea (Cell Paste J, manufactured by Eiwa Chemical Industry Co., Ltd.). Polyester is
Unitika ester manufactured by Unitika. Polyethylene (HDPE, weight average molecular weight (Mw) 1.7 × 10 ⁵ )
Is measured by a Dupont DSC at a temperature rising rate of 10 ° C. /
The melting point peak temperature (melting point) measured under the conditions of a sample weight of about 5 mg was 135 ° C. Regarding the elongated body,
“L: length” means the average length (μm), and “D: diameter”
Means an average diameter (μm).

In Example 7, the highest vulcanization temperature at the time of vulcanization of the rubber composition was 175 ° C. as measured by embedding a thermocouple in the rubber composition. The elongated body in Example 7 is an elongated resin manufactured according to a normal melt spinning method, and has a circular cross section in a direction perpendicular to the axis. In Example 7, the melting point of the long resin is lower than the maximum vulcanization temperature during vulcanization of the rubber composition. In Example 7, during the vulcanization of the rubber composition, until the temperature of the rubber composition reaches the maximum vulcanization temperature, the viscosity of the long resin is lower than the viscosity of the rubber matrix. (See FIG. 7).

From the results of Tables 1 and 2, the following is clear. That is, a comparison between Example 1 and Comparative Example 2 or a comparison between Example 2 and Comparative Example 4, Comparative Example 8, and Comparative Example 9 shows that carbon black that satisfies Formulas (1) and (2) is used. It is clear that the present invention can improve the performance on ice and the abrasion resistance in a better balance (see FIG. 9). In addition, a comparison between Example 2 and Comparative Example 5 reveals that the present invention having a long body having (L / D) of 3 or more can improve the on-ice performance and the wear resistance in a well-balanced manner ( (See FIG. 9). Further, a comparison between Example 2 and Comparative Examples 6 and 10 reveals that the on-ice performance and the wear resistance can be improved in a well-balanced manner when the content of the elongated body is within the range specified by the present invention. (See FIG. 9). Further, a comparison between Example 2 and Comparative Example 7 reveals that when the content of carbon black is within the range specified in the present invention, the performance on ice and the abrasion resistance can be improved in a well-balanced manner (see FIG. 9). ).

[0108]

According to the present invention, the above-mentioned conventional problems can be solved. Further, according to the present invention, without deteriorating wear resistance on a dry road surface, the ability to remove water generated on an ice surface is excellent, the coefficient of friction with the ice surface is large, and braking / A vulcanized rubber which can be suitably used for a tire having drastically improved driving performance (performance on ice), a structure such as a tread of the tire which needs to suppress slip on ice, and a raw material of the vulcanized rubber It is possible to provide a rubber composition that can be suitably used as the above.

[Brief description of the drawings]

FIG. 1 is a graph for explaining a range of carbon black that can be used in the present invention in a graph showing a relationship between (DBP) and (N ₂ SA).

FIG. 2 is an explanatory diagram illustrating the principle of aligning the orientation of a long resin.

FIG. 3 is a schematic cross-sectional explanatory view of a vulcanized rubber of the present invention.

FIG. 4 is a partial schematic cross-sectional explanatory view of the tire of the present invention.

FIG. 5 is a partially schematic explanatory view of a peripheral surface of the tire of the present invention.

FIG. 6 is a schematic partial cross-sectional explanatory view of a tread of the tire of the present invention.

FIG. 7 is a graph showing a relationship between temperature (vulcanization time), viscosity of a rubber matrix, and viscosity of a long resin.

FIG. 8 is a partially enlarged schematic explanatory view of a worn tread of the tire of the present invention.

FIG. 9 is a diagram of comparison data between a tire of the present invention and a tire of a comparative example regarding performance on ice and abrasion resistance.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 pair of bead portions 2 carcass 3 belt 4 tire 5 tread 6 cap portion 7 base portion 8 circumferential groove 9 lateral groove 10 block 11 sipes 12 elongated bubble 13 concave portion 14 protective layer 15 elongated body 16 rubber matrix 17 base 18 Spherical bubble 19 recess

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁶ Identification code FI C08L 7/00 C08L 7/00

Claims (11)

[Claims] 1. A rubber matrix comprising at least one rubber component selected from natural rubber and diene-based synthetic rubber, and at least 10 parts by weight of carbon black with respect to 100 parts by weight of the rubber component; Ratio (L / D) of average length (L) and average diameter (D) with respect to parts by weight
And 1 to 20 parts by weight of a long body having a value of at least 3. The carbon black is represented by the formula (1): (DBP) ≧ 0.1
86 × (N ₂ SA) +89, and equation (2): (DB
P) ≧ 1000 / (N ₂ SA) +100. 2. The rubber composition according to claim 1, wherein the rubber matrix contains a foaming agent. 3. The rubber composition according to claim 1, wherein the elongated body contains at least short fibers. 4. The elongate body contains at least an elongate resin whose viscosity is lower than the viscosity of the rubber matrix until the temperature of the rubber composition reaches the maximum vulcanization temperature during vulcanization. 3. The rubber composition according to 1 or 2. 5. The rubber composition according to claim 4, wherein the long resin contains a crystalline polymer, and has a melting point lower than the maximum vulcanization temperature. 6. The rubber composition according to claim 4, wherein the long resin softens at a temperature not higher than the extrusion temperature. 7. A vulcanized rubber obtained by vulcanizing the rubber composition according to claim 3 and comprising short fibers. 8. A vulcanized rubber obtained by vulcanizing the rubber composition according to claim 4 and having elongated cells. 9. The method according to claim 7, wherein the average foaming ratio is 3 to 40%.
Or the vulcanized rubber according to 8. 10. A vehicle comprising: a pair of bead portions; a carcass connected to the bead portions in a toroidal shape; a belt and a tread for clinching a crown portion of the carcass;
A tire, wherein at least the tread comprises the vulcanized rubber according to any one of claims 7 to 9. 11. The tire according to claim 10, wherein at least one of the short fiber and the long bubble is oriented along the tire circumferential direction.