阅读说明：本技术 橡胶组合物和轮胎 (Rubber composition and tire ) 是由 谷真佐人 于 2018-07-09 设计创作，主要内容包括：本发明提供一种配合有非纤维状的钛酸盐化合物颗粒且该钛酸盐化合物颗粒的分散性优异、并且具有优异的抗湿滑性和耐磨损性的橡胶组合物。该橡胶组合物中，在橡胶成分中配合有平均粒径小于30μm且BET比表面积为2m<Sup>2</Sup>/g以上的非纤维状钛酸盐化合物颗粒、和BET比表面积为50～250m<Sup>2</Sup>/g的二氧化硅颗粒。(The present invention provides a rubber composition containing non-fibrous titanate compound particles, which is excellent in dispersibility of the titanate compound particles and has excellent wet skid resistance and abrasion resistance. In the rubber composition, a rubber component is blended with a rubber having an average particle diameter of less than 30 μm and a BET specific surface area of 2m 2 Non-fibrous titanate compound particles having a specific particle size of at least one gramAnd a BET specific surface area of 50 to 250m 2 Silica particles per gram.)

1. A rubber composition characterized by:

the rubber component contains a polymer having an average particle diameter of less than 30 μm and a BET specific surface area of 2m²Non-fibrous titanate compound particles of/g or moreParticles and a BET specific surface area of 50 to 250m²Silica particles per gram.

2. The rubber composition according to claim 1, wherein:

the titanate compound constituting the non-fibrous titanate compound particles is selected from the group consisting of₂Ti_nO_(2n+1)、R_xM_yTi_(2－y)O₄、K_0.5～0.8Li_0.27Ti_1.73O_3.85～3.95And K_0.2～0.8Mg_0.4Ti_1.6O_3.7～3.95At least one kind of the group consisting of (1),

wherein A is 1 or 2 or more selected from alkali metals, and n is 2-8; r is an alkali metal other than lithium, M is 1 or 2 or more selected from the group consisting of lithium, magnesium, zinc, nickel, copper, iron, aluminum, gallium and manganese, x is 0.5 to 1.0, and y is 0.25 to 1.0.

3. The rubber composition according to claim 1 or 2, wherein:

a treatment layer formed of a surface treatment agent is provided on the surface of the non-fibrous titanate compound particles.

4. The rubber composition according to any one of claims 1 to 3, wherein:

the rubber component is a diene rubber.

5. The rubber composition according to any one of claims 1 to 4, wherein:

the amount of the non-fibrous titanate compound particles is 1 to 200 parts by mass per 100 parts by mass of the rubber component.

6. The rubber composition according to any one of claims 1 to 5, wherein:

the silica particles are incorporated in an amount of 20 to 120 parts by mass per 100 parts by mass of the rubber component.

7. The rubber composition according to any one of claims 1 to 6, wherein:

carbon black particles are also blended in the rubber component.

8. The rubber composition according to any one of claims 1 to 7, wherein:

the rubber composition is used for a tire tread.

9. A tire comprising a tread portion and the rubber composition according to any one of claims 1 to 8.

Technical Field

The present invention relates to a rubber composition containing titanate compound particles as a filler, and a tire using the rubber composition.

Background

When an automobile runs on a wet road surface in rainy weather, water is present between tires and the road surface, and therefore, the grip performance of the tires is reduced, and the braking distance during braking is increased. In order to improve the wet skid resistance (wet grip), various studies have been made on blending a filler as a filler into a rubber component. For example, patent document 1 discloses a rubber composition for a tire tread surface, wherein 1 to 30 parts by mass of potassium titanate fibers having an average fiber length of 1 to 30 μm are blended in a rubber component.

On the other hand, it is known that a phenol resin composition containing potassium titanate fibers can be used as a friction material for a brake. In particular, potassium titanate fibers can be used as friction adjusting materials. However, potassium titanate fibers have a major average fiber diameter of 0.1 to 0.5 μm and an average fiber length of 10 to 20 μm, and contain WHO fibers (fibrous particles having a major axis of 5 μm or more, a minor axis of 3 μm or less, and an aspect ratio of 3 or more) prescribed by the World Health Organization (WHO), and therefore, it has been widely adopted to blend non-fibrous titanate compound particles as a friction adjusting material.

Disclosure of Invention

Technical problem to be solved by the invention

The rubber composition of patent document 1 uses fibrous titanate compound particles, and has insufficient wet skid resistance and insufficient dispersibility of the titanate compound particles. Further, it is expected that non-fibrous titanate compound particles are blended in a rubber component to function as a friction adjusting material and be used for a tire, but this is not known.

The purpose of the present invention is to provide a rubber composition containing non-fibrous titanate compound particles, which has excellent dispersibility of the titanate compound particles and excellent wet skid resistance and abrasion resistance, and a tire using the rubber composition.

Technical solution for solving technical problem

The present invention provides the following rubber composition and a tire using the same.

Item 1 is a rubber composition comprising a rubber component and, compounded therein, a rubber polymer having an average particle diameter of less than 30 μm and a BET specific surface area of 2m²Non-fibrous titanate compound particles having a BET specific surface area of 50 to 250m²Silica particles per gram.

The rubber composition according to item 1, wherein the titanate compound constituting the non-fibrous titanate compound particles is selected from the group consisting of the titanate compounds represented by the formula A₂Ti_nO_(2n+1)[ wherein A is 1 or 2 or more selected from alkali metals, n is 2 to 8 ], R_xM_yTi_(2－y)O₄Wherein R is an alkali metal other than lithium, M is 1 or 2 or more selected from the group consisting of lithium, magnesium, zinc, nickel, copper, iron, aluminum, gallium and manganese, x is 0.5 to 1.0, y is 0.25 to 1.0, K_0.5～0.8Li_0.27Ti_1.73O_3.85～3.95And K_{0.2～ 0.8}Mg_0.4Ti_1.6O_3.7～3.95At least 1 kind of (1).

The rubber composition according to item 1 or 2, wherein a treated layer comprising a surface-treating agent is provided on the surface of the non-fibrous titanate compound particles.

The rubber composition as described in any one of the above items 1 to 3, wherein the rubber component is a diene rubber.

The rubber composition as described in any of the items 1 to 4, wherein the amount of the non-fibrous titanate compound particles is 1 to 200 parts by mass per 100 parts by mass of the rubber component.

The rubber composition as described in any one of the items 1 to 5, wherein the silica particles are incorporated in an amount of 20 to 120 parts by mass per 100 parts by mass of the rubber component.

The rubber composition according to any one of the items 1 to 6, wherein carbon black particles are further compounded in the rubber component.

The rubber composition according to any one of the items 1 to 7, which is used for a tread of a tire.

The tire according to item 9, wherein the rubber composition according to any one of items 1 to 8 is used for a tread portion.

ADVANTAGEOUS EFFECTS OF INVENTION

According to the present invention, it is possible to provide a rubber composition containing non-fibrous titanate compound particles, which is excellent in dispersibility of the titanate compound particles and has excellent wet skid resistance and abrasion resistance, and a tire using the rubber composition.

Drawings

Fig. 1 is a scanning electron micrograph showing titanate compound particles of production example 1.

Fig. 2 is a scanning electron micrograph showing titanate compound particles of production example 2.

Detailed Description

Hereinafter, preferred embodiments will be described. However, the following embodiments are merely examples, and the present invention is not limited to the following embodiments.

In the rubber composition of the present invention, a rubber component is compounded with a compound having an average particle diameter of less than 30 μm and a BET specific surface area of 2m²Non-fibrous titanate compound particles (hereinafter, may be simply referred to as "titanate compound particles") having a BET specific surface area of 50 to 250m²The silica particles per gram may be mixed with other materials as required. According to the present invention, it is possible to provide a rubber composition having excellent dispersibility of titanate compound particles in the rubber composition during and after the preparation of the rubber composition and excellent wet skid resistance and abrasion resistance, and a tire using the rubber composition. Further, since non-fibrous titanate compound particles are used, there is no tire wear powder containingConcern about fibrous substances derived from titanate compound particles.

The rubber component used in the rubber composition of the present invention is not particularly limited, and a diene rubber is preferably used from the viewpoint of excellent strength. Examples of the diene rubber include Natural Rubber (NR), Isoprene Rubber (IR), Styrene Butadiene Rubber (SBR), Butadiene Rubber (BR), butyl rubber (IIR), ethylene propylene diene rubber (EPDM), acrylonitrile-butadiene rubber (NBR), styrene-isoprene-butadiene rubber (SIBR), Chloroprene Rubber (CR), and the like, and 1 or 2 or more rubber components among them are preferably contained. From the viewpoint of balance between low rolling resistance and high wet skid resistance, styrene-butadiene rubber (SBR) and Butadiene Rubber (BR) are more preferably used. The mixing ratio (SBR/BR) of the styrene-butadiene rubber (SBR) to the Butadiene Rubber (BR) is preferably 60/40 to 100/0.

The titanate compound particles used in the present invention may have an average particle diameter of less than 30 μm and a BET specific surface area of 2m²Non-fibrous particles (non-fibrous particles) having a spherical shape, a lamellar shape, a plate shape, a columnar shape, a rod shape, a columnar shape, a block shape, a porous shape, a shape having a plurality of projections (an amoeba shape, a boomerang shape, a cross shape, a tawny shape, etc.) or the like of/g or more can be used by appropriately selecting arbitrary particles from known titanate compound particles. The shape of the titanate compound particles can be analyzed by observation with a scanning electron microscope, for example.

In the present invention, the fibrous particles mean: when the longest major axis of a cuboid having the smallest volume (circumscribed cuboid) among cuboids circumscribed with particles is L, the next major axis is B, and the shortest axis is T (B > T), L/T and L/B are 5 or more particles. The term "non-fibrous particles" means particles other than fibrous particles, and means: and particles having a length L/B of less than 5, wherein L is the longest major diameter of a cuboid having the smallest volume (circumscribed cuboid) among cuboids circumscribed by the particles, B is the minor major diameter, and T is the shortest dimension (B > T).

In addition, having a plurality of projections means: the shape of the projection on the plane is a so-called indefinite shape having a shape having projections in 2 or more directions, unlike at least a normal polygon, circle, ellipse, or the like. Specifically, the shape having the convex portion means: when a photograph (projection view) obtained by a scanning electron microscope is fitted into a polygon, a circle, an ellipse, or the like (basic figure), a portion corresponding to a portion protruding from the polygon is formed.

The average particle diameter of the titanate compound particles used in the present invention is less than 30 μm, preferably 0.1 μm or more, and more preferably 0.6 μm or more. Preferably 3 μm or less, more preferably 1.5 μm or less, and further preferably 1 μm or less. By adjusting the average particle diameter within such a range, more excellent dispersibility, wet skid resistance and abrasion resistance can be obtained.

The average particle diameter of the titanate compound particles can be measured by a laser diffraction/scattering method, and is a particle diameter at 50% cumulative standard in the particle size distribution measured by the laser diffraction/scattering method (50% cumulative particle diameter on volume basis), that is, D₅₀(median diameter). The volume-based cumulative 50% particle diameter (D)₅₀) The particle size distribution was determined on a volume basis, and the number of particles was measured from the side where the particle size was smaller in a cumulative curve in which the total volume was 100%, and the cumulative value reached 50%.

The BET specific surface area of the titanate compound particles used in the present invention is 2m²A concentration of 2 to 300m or more²(ii) g, more preferably 7 to 100m²(ii) in terms of/g. By adjusting the BET specific surface area within such a range, more excellent dispersibility, wet skid resistance, and abrasion resistance can be obtained. The BET specific surface area of the titanate compound particles can be measured in accordance with JIS Z8830. The BET method is a method of adsorbing nitrogen gas having a known occupied area on the surface of sample powder particles and determining the specific surface area of the sample powder particles from the adsorbed amount thereof, and the specific surface area determined by this method is referred to as "BET specific surface area".

As the titanate compound constituting the titanate compound particles used in the present invention, salts of at least 1 element selected from alkali metals and alkaline earth metals are preferable. Examples of the alkali metal include lithium, sodium, potassium, rubidium, cesium, and francium, and lithium, sodium, and potassium are preferable. Examples of the alkaline earth metal include beryllium, magnesium, calcium, strontium, barium and radium, and magnesium and calcium are preferable.

Specific examples of the titanate compound include: composition formula A₂Ti_nO_(2n+1)[ wherein A is 1 or 2 or more selected from alkali metals, n is 2 to 8 ], R_xM_yTi_(2－y)O₄Wherein R is an alkali metal other than lithium, M is 1 or 2 or more selected from the group consisting of lithium, magnesium, zinc, nickel, copper, iron, aluminum, gallium and manganese, x is 0.5 to 1.0, y is 0.25 to 1.0, K_0.5～0.8Li_0.27Ti_1.73O_3.85～3.95、K_0.2～0.8Mg_0.4Ti_1.6O_3.7～3.95And the like. These may be used alone, or 2 or more of them may be used in combination. Among these, a having a tunnel structure is preferable₂Ti_nO_(2n+1)[ in the formula, A is 1 or 2 or more selected from alkali metals, and n is 2 to 8 ], and specific examples thereof include Na₂Ti₆O₁₃、Na₂Ti₈O₁₇、K₂Ti₆O₁₃、K₂Ti₈O₁₇And the like. By forming the structure to have a tunnel structure, elution of the base from the titanate compound can be further suppressed.

The water dispersion pH of the titanate compound particles is preferably 7 to 11. When the pH of the aqueous dispersion of titanate compound particles is in such a range, the decrease in wear resistance due to acidic impurities contained in the titanate compound particles can be further suppressed. In the present invention, the water dispersion pH means the pH of a 1 mass% slurry obtained by dispersing titanate compound particles in water at 20 ℃.

The titanate compound particles used in the present invention preferably have a treated layer formed of a surface-treating agent on the surface of the titanate compound particles for the purpose of further improving dispersibility, further improving adhesion to rubber components, and the like. The surface treatment agent includes coupling agents such as a titanate coupling agent, a silane coupling agent, an aluminate coupling agent, and a zirconium coupling agent, and among these, a titanate coupling agent, a silane coupling agent, and an aluminate coupling agent are preferable. These can be used alone in 1 kind, also can be mixed with more than 2 kinds of use.

Examples of the titanate coupling agent include isopropyltristearyltitanate, isopropyltris (dioctylphosphatoxy) titanate, isopropyltris (N-aminoethyl) titanate, tetraoctylbis (ditridecylphosphate) titanate, tetrakis (2-2-diallyloxymethyl-1-butyl) bis (ditridecylphosphate) titanate, bis (dioctylphosphatoxy) oxyacetate titanate, bis (dioctylphosphatoxy) ethylene titanate and the like. Of these, isopropyltris (N-aminoethyl) titanate is preferred.

Examples of the silane coupling agent include sulfide-based, polysulfide-based, thioester-based, thiol-based, olefin-based, epoxy-based, amino-based, alkyl-based silane coupling agents, and 1 kind of these may be used alone, or 2 or more kinds may be mixed and used. Among these, sulfide-based silane coupling agents and amino-based silane coupling agents are preferable.

Examples of the sulfide-based silane coupling agent include: bis (3-triethoxysilylpropyl) tetrasulfide, bis (3-trimethoxysilylpropyl) tetrasulfide, bis (3-methyldimethoxysilylpropyl) tetrasulfide, bis (2-triethoxysilylethyl) tetrasulfide, bis (3-triethoxysilylpropyl) disulfide, bis (3-trimethoxysilylpropyl) disulfide, bis (3-methyldimethoxysilylpropyl) disulfide, bis (2-triethoxysilylethyl) disulfide, bis (3-triethoxysilylpropyl) trisulfide, bis (3-trimethoxysilylpropyl) trisulfide, bis (3-methyldimethoxysilylpropyl) trisulfide, bis (2-triethoxysilylethyl) trisulfide, bis (3-monoethoxydimethylsilylpropyl) tetrasulfide, Bis (3-monoethoxydimethylsilylpropyl) trisulfide, bis (3-monoethoxydimethylsilylpropyl) disulfide, bis (3-monomethoxydimethylsilylpropyl) tetrasulfide, bis (3-monomethoxydimethylsilylpropyl) trisulfide, bis (3-monomethoxydimethylsilylpropyl) disulfide, bis (2-monoethoxydimethylsilylethyl) tetrasulfide, bis (2-monoethoxydimethylsilylethyl) trisulfide, bis (2-monoethoxydimethylsilylethyl) disulfide and the like. Among these, bis (3-triethoxysilylpropyl) tetrasulfide is preferred.

Examples of the thioester-based silane coupling agent include 3-hexanoylthiopropyltriethoxysilane, 3-octanoylthiopropyltriethoxysilane, 3-decanoylthiopropyltriethoxysilane, 3-lauroylthiopropyltriethoxysilane, 2-hexanoylthioethyltriethoxysilane, 2-octanoylthioethyltriethoxysilane, 2-decanoylthioethyltriethoxysilane, 2-lauroylthioethyltriethoxysilane, 3-hexanoylthiopropyltrimethoxysilane, 3-octanoylthiopropyltrimethoxysilane, 3-decanoylthiopropyltrimethoxysilane, 3-lauroylthiopropyltrimethoxysilane, 2-hexanoylthioethyltrimethoxysilane, 2-octanoylthioethyltrimethoxysilane, 2-decanoylthioethyltrimethoxysilane, 2-octanoylthioethyltrimethoxysilane, 2-lauroylthioethyltrimethoxysilane and the like.

Examples of the thiol-based silane coupling agent include 3-mercaptopropyltrimethoxysilane, 3-mercaptopropyltriethoxysilane, and 3-mercaptopropylmethyldimethoxysilane.

Examples of the olefinic silane coupling agent include dimethoxymethylvinylsilane, vinyltrimethoxysilane, dimethylethoxyvinylsilane, diethoxymethylvinylsilane, triethoxyvinylsilane, vinyltris (2-methoxyethoxy) silane, allyltrimethoxysilane, allyltriethoxysilane, p-vinyltrimethoxysilane, 3- (methoxydimethoxydimethylsilyl) propyl acrylate, 3- (trimethoxysilyl) propyl acrylate, 3- [ dimethoxy (meth) silyl ] propyl methacrylate, 3- (trimethoxysilyl) propyl methacrylate, 3- [ dimethoxy (meth) silyl ] propyl methacrylate, 3- (triethoxysilyl) propyl methacrylate, and the like, 3- [ tris (trimethylsiloxy) silyl ] propyl methacrylate, and the like.

Examples of the epoxy-based silane coupling agent include 3-glycidoxypropyl (dimethoxy) methylsilane, 3-glycidoxypropyltrimethoxysilane, diethoxy (3-glycidoxypropyl) methylsilane, triethoxy (3-glycidoxypropyl) silane, and 2- (3, 4-epoxycyclohexyl) ethyltrimethoxysilane.

Examples of the amino-based silane coupling agent include N-2- (aminoethyl) -3-aminopropylmethyldimethoxysilane, N-2- (aminoethyl) -3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, 3-ethoxysilyl-N- (1, 3-dimethylbutylidene) propylamine, N-phenyl-3-aminopropyltrimethoxysilane, and N- (vinylbenzyl) -2-aminoethyl-3-aminopropyltrimethoxysilane. Among these, 3-aminopropyltriethoxysilane is preferable.

Examples of the alkyl-based silane coupling agent include methyltrimethoxysilane, dimethyldimethoxysilane, trimethylmethoxysilane, methyltriethoxysilane, ethyltrimethoxysilane, n-propyltrimethoxysilane, isobutyltrimethoxysilane, isobutyltriethoxysilane, n-hexyltrimethoxysilane, n-hexyltriethoxysilane, cyclohexylmethyldimethoxysilane, n-octyltriethoxysilane, and n-decyltrimethoxysilane.

Among these silane coupling agents, bis (3-triethoxysilylpropyl) tetrasulfide and 3-aminopropyltriethoxysilane are particularly preferably used.

Examples of the aluminate coupling agent include aluminum acetylacetonate diisopropyl ester, diisopropoxyemonoethyl aluminum acetoacetate, triethyl aluminum acetoacetate, and aluminum triacetylacetonate. Among these, preferred is an acetoacetoxy aluminum diisopropyl ester.

Examples of the zirconate coupling agent include zirconium tetraacetylacetonate, zirconium dibutoxybisacetylacetonate, zirconium tetraethylacetoacetate, zirconium tributoxybutylethylacetoacetate, and zirconium tributoxyacetylacetonate.

As a method for forming a treated layer composed of a surface treatment agent on the surface of titanate compound particles, a known surface treatment method can be used. For example, the following method can be employed: a wet method of dissolving a surface-treating agent in a solvent (for example, water, alcohol, or a mixed solvent thereof) for promoting hydrolysis to form a solution and spraying the solution on titanate compound particles, or a bulk blending method of mixing titanate compound particles and a surface-treating agent in a rubber component, and the like.

The amount of the surface-treating agent when the surface-treating agent is applied to the surface of the titanate compound particles of the present invention is not particularly limited, and in the case of the wet method, a solution of the surface-treating agent may be sprayed in a proportion of 0.1 to 20 parts by mass, preferably 0.1 to 10 parts by mass, relative to 100 parts by mass of the titanate compound particles. In the case of the bulk blending method, the surface treatment agent may be added to the rubber component in a proportion of preferably 1 to 50 parts by mass, more preferably 10 to 40 parts by mass, relative to 100 parts by mass of the titanate compound particles. When the amount of the surface-treating agent is within the above range, the adhesiveness with the rubber component can be improved, and the dispersibility of the titanate compound particles can be further improved.

The method for producing the titanate compound particles used in the present invention is not particularly limited as long as the above-described composition and properties can be obtained, and for example, porous titanate compound particles having a pore diameter in the range of 0.01 to 1.0 μm and a cumulative pore volume of 5% or more can be produced by performing dry pulverization treatment or wet pulverization treatment, and further performing dry classification treatment or wet classification treatment as necessary to adjust the average particle diameter and specific surface area by a known method, wherein the porous titanate compound particles are formed by bonding crystal grains of a titanate compound by sintering and/or welding or the like. This is because non-fibrous fine particles can be easily produced by pulverizing the porous titanate compound particles. Further, it is considered that since the fine particles of the titanate compound are porous particles of the titanate compound bonded by sintering and/or welding, the particles become finer by a shearing force at the time of kneading the rubber composition, and can be uniformly dispersed in the rubber composition.

The cumulative pore volume of the porous titanate compound particles is preferably 10% or more, more preferably 15% or more. The upper limit of the cumulative pore volume is preferably 40%, more preferably 30%. When the cumulative pore volume is too small, the production of fine particles may be difficult. When the cumulative pore volume is too large, the bonding portion between the crystal grains of the porous titanate compound particles becomes weak, and the porous structure may not be maintained. The cumulative pore volume can be measured by mercury intrusion method.

In addition, the BET specific surface area of the porous titanate compound particles is preferably 1 to 13m²In the range of/g, more preferably in the range of 3 to 9m²In the range of/g. When the BET specific surface area is too small, the production of fine particles may be difficult. When the BET specific surface area is too large, the chemical reaction in the firing step may not be completed.

The particle shape of the porous titanate compound particles is preferably a powder shape such as a spherical shape or an irregular shape, and more preferably a non-fibrous shape. Spherical shapes are particularly preferred.

The particle size of the porous titanate compound particles is not particularly limited, and the average particle size is preferably 5 to 500. mu.m, more preferably 10 to 300. mu.m, and still more preferably 20 to 100. mu.m. These various particle shapes and particle sizes can be arbitrarily controlled depending on the production conditions, particularly the raw material composition, the firing conditions, the pulverization treatment conditions, and the like.

The method for producing the porous titanate compound particles is not particularly limited as long as the above-described characteristics can be obtained, and examples thereof include: and a method of producing the titanium alloy by dry granulation of a pulverized mixture obtained by mechanically pulverizing a titanium source and an alkali metal source and firing the same.

As the mechanical pulverization, a method of pulverizing while applying physical impact may be mentioned. Specifically, pulverization by a vibration mill can be mentioned. It is considered that by performing the pulverization treatment by the vibration mill, the shear stress due to the pulverization of the mixed powder causes the disturbance of the atomic arrangement and the reduction of the interatomic distance at the same time, and the atomic movement of the contact portion of the different particles occurs, and as a result, the metastable phase can be obtained. This provides a pulverized mixture having high reactivity, and the firing temperature described below can be lowered, and even if the pulverized mixture is granulated, unreacted materials can be reduced. Since mechanical pulverization efficiently applies shear stress to the raw material, dry processing without using water or a solvent is preferable.

The treatment time for the mechanical pulverization is not particularly limited, but is preferably in the range of 0.1 to 2 hours in general.

Granulation of the pulverized mixture is performed by dry granulation without using water and a solvent. The dry granulation can be carried out by a known method, and examples thereof include rotary granulation, fluidized bed granulation, and stirring granulation. In wet granulation, vaporization of a liquid material in the granulated material is accompanied in the drying step of the granulated material, and as a result, porous particles having large voids therein are obtained, which is not preferable because the powder strength is lowered. Further, heating is required to vaporize water and a solvent, and mass productivity is also poor.

The temperature for firing the granulated substance may be appropriately selected depending on the composition of the desired titanate compound, and is preferably in the range of 650 to 1000 ℃, and more preferably in the range of 800 to 950 ℃. The firing time is preferably 0.5 to 8 hours, more preferably 2 to 6 hours.

The titanium source is titanium dioxide or a compound that produces titanium dioxide by firing. The compound that produces titania by firing is not particularly limited as long as it contains titanium element and does not inhibit the production of titania by firing, and examples thereof include compounds that become titania by firing in air. Examples of such a compound include orthotitanic acid or a salt thereof, metatitanic acid or a salt thereof, titanium hydroxide, peroxotitanic acid or a salt thereof, and the like. The titanium source may be used alone or in combination of 2 or more. Among these, titanium dioxide is preferred. The crystal system of titanium dioxide is preferably rutile type or anatase type.

The alkali metal source is an oxide of an alkali metal or a compound that generates an oxide of an alkali metal by firing. The compound that forms an oxide of an alkali metal by firing may be any material that contains an alkali metal and does not inhibit the formation of an oxide of an alkali metal by firing, and examples thereof include organic acid salts such as carbonates, bicarbonates, hydroxides, and acetates of alkali metals, sulfates, nitrates, and the like. The alkali metal source can be used alone, can also be combined with 2 or more. Among these, carbonates of alkali metals are preferable.

The mixing ratio of the titanium source and the alkali metal source may be appropriately selected depending on the composition of the objective titanate compound particles.

The amount of titanate compound particles incorporated in the rubber composition of the present invention is preferably 1 to 200 parts by mass, more preferably 20 to 60 parts by mass, per 100 parts by mass of the rubber component. By setting the range, more excellent wet skid resistance and wear resistance can be obtained.

The BET specific surface area of the silica particles in the rubber composition of the present invention is 50 to 250m²A ratio of 80 to 210 m/g²(iv)/g, more preferably 100 to 190m²(ii) in terms of/g. By adjusting the BET specific surface area within such a range, more excellent dispersibility, wet skid resistance, and abrasion resistance can be obtained. The BET specific surface area of the silica particles can be measured in accordance with JIS Z8830. The BET method is a method of adsorbing nitrogen gas having a known occupied area on the surface of sample powder particles and determining the specific surface area of the sample powder particles from the adsorbed amount thereof, and the specific surface area determined by this method is referred to as "BET specific surface area".

The silica constituting the silica particles in the rubber composition of the present invention means a silicic acid-based filler, and not only means silica in a narrow sense, but also can be appropriately selected and used from conventional materials used as fillers for reinforcement. Examples thereof include wet silica (hydrous silicic acid) and dry silica (anhydrous silica). Among these, wet silica is preferable from the viewpoint of further improving the processability, wet skid resistance and abrasion resistance. These may be used alone in 1 kind, or may be used in combination of 2 or more kinds. In order to further improve the affinity with the rubber component, a treated layer formed of a surface treatment agent is preferably formed on the surface. The surface-treating agent may be the same as the surface-treating agent listed in the description of the titanate compound particles. In addition, as for the method of forming the treated layer formed of the surface treatment agent, the same method as in the case of the titanate compound particles may be used.

From the viewpoint of further improving the processability, wet skid resistance and abrasion resistance of the rubber composition obtained, the silica particles preferably have an average secondary particle diameter of 0.04 to 3 μm, more preferably 0.1 to 1 μm, and still more preferably 0.2 to 0.7. mu.m. The average secondary particle diameter of the silica particles can be measured by a laser diffraction/scattering method, and is a particle diameter at 50% cumulative standard in the particle size distribution measured by the laser diffraction/scattering method (50% cumulative particle diameter on a volume basis), that is, D₅₀(median diameter). The volume-based cumulative 50% particle diameter (D)₅₀) The particle size distribution was determined on a volume basis, and the number of particles was measured from the side where the particle size was smaller in a cumulative curve in which the total volume was 100%, and the cumulative value reached 50%.

The amount of silica particles to be incorporated in the rubber composition of the present invention is preferably 20 to 120 parts by mass, more preferably 25 to 100 parts by mass, and still more preferably 30 to 90 parts by mass, per 100 parts by mass of the rubber component. By setting the range, more excellent wet skid resistance and wear resistance can be obtained.

In the rubber composition of the present invention, carbon black particles may be further blended in the rubber component from the viewpoint of further improving the abrasion resistance.

From moreThe BET specific surface area of the carbon black particles is preferably 20 to 160m from the viewpoint of further improving dispersibility, mechanical strength and hardness²A concentration of 40 to 130m²(ii) g, more preferably 50 to 120m²(ii) in terms of/g. The BET specific surface area of the carbon black particles can be determined in accordance with JIS Z8830. The BET method is a method of adsorbing nitrogen gas having a known occupied area on the surface of sample powder particles and determining the specific surface area of the sample powder particles from the adsorbed amount thereof, and the specific surface area determined by this method is referred to as "BET specific surface area".

The average secondary particle diameter of the carbon black particles is preferably 0.05 to 3 μm, more preferably 0.1 to 1.0 μm, and still more preferably 0.2 to 0.9 μm, from the viewpoint of further improving dispersibility, mechanical strength, and hardness. The average secondary particle diameter of the carbon black particles can be measured by a laser diffraction/scattering method, and is a particle diameter at 50% cumulative reference in the particle size distribution measured by the laser diffraction/scattering method (50% cumulative particle diameter on volume basis), that is, D₅₀(median diameter). The volume-based cumulative 50% particle diameter (D)₅₀) The particle size distribution was determined on a volume basis, and the number of particles was measured from the side where the particle size was smaller in a cumulative curve in which the total volume was 100%, and the cumulative value reached 50%.

Examples of the carbon black constituting the carbon black particles include furnace black, thermal black, acetylene black, and ketjen black. Among these, furnace carbon black is preferable from the viewpoint of further improving the mechanical strength of the rubber composition. These may be used alone in 1 kind, or may be used in combination of 2 or more kinds. In addition, the surface may be subjected to an organic treatment in order to further improve the affinity with the rubber component.

The amount of the carbon black particles to be blended in the rubber composition of the present invention is preferably 2 to 50 parts by mass, more preferably 3 to 30 parts by mass, and still more preferably 10 to 20 parts by mass, per 100 parts by mass of the rubber component.

In the rubber composition of the present invention, calcium carbonate (CaCO) may be blended as a reinforcing filler₃) Alumina (Al)₂O₃) Hydration oxidationAluminum (Al)₂O₃·H₂O), aluminum hydroxide [ Al (OH)₃]Aluminum carbonate [ Al ]₂(CO₃)₃]Magnesium hydroxide [ Mg (OH) ]₂]Magnesium oxide (MgO), magnesium carbonate (MgCO)₃) Talc (3 MgO.4SiO)₂·H₂O), attapulgite (5 MgO.8SiO)₂·9H₂O), titanium white (TiO)₂) Titanium black (TiO)_2n－1) Calcium oxide (CaO), calcium hydroxide [ Ca (OH) ]₂]Aluminum magnesium oxide (MgO. Al)₂O₃) Clay (Al)₂O₃·2SiO₂) Kaolin (Al)₂O₃·2SiO₂·2H₂O), pyrophyllite (Al)₂O₃·4SiO₂·H₂O), bentonite (Al)₂O₃·4SiO₂·2H₂O), aluminum silicate (Al)₂SiO₅、Al₄·3SiO₄·5H₂O, etc.), magnesium silicate (Mg)₂SiO₄、MgSiO₃Etc.), calcium silicate (Ca)₂·SiO₄Etc.) calcium aluminum silicate (Al)₂O₃·CaO·2SiO₂Etc.), calcium magnesium silicate (CaMgSiO)₄) Zirconium oxide (ZrO)₂) Zirconium hydroxide [ ZrO (OH) ]₂·nH₂O]Zirconium carbonate [ Zr (CO) ]₃)₂]Zinc acrylate, zinc methacrylate, crystalline aluminosilicate containing charge-compensating hydrogen such as various zeolites, and alkali metal or alkaline earth metal, and the like. These reinforcing fillers may be used in any 1 kind or in a mixture of 2 or more kinds. The total amount of the reinforcing filler is preferably 5 to 200 parts by mass, more preferably 30 to 100 parts by mass, per 100 parts by mass of the rubber component.

In addition to the above-mentioned components, compounding agents generally used in the rubber field, such as a vulcanizing agent, a vulcanization accelerator auxiliary, an antioxidant, a softener, a plasticizer, an anti-scorching agent, an antiozonant, a foaming agent, and a vulcanization retarder, may be appropriately compounded in the rubber composition of the present invention.

As the vulcanizing agent, an organic peroxide or a sulfur-based vulcanizing agent may be blended. Examples of the organic peroxide include benzoyl peroxide, dicumyl peroxide, di-t-butyl peroxide, t-butylcumyl peroxide, methyl ethyl ketone peroxide, cumene hydroperoxide, 2, 5-dimethyl-2, 5-di (t-butylperoxy) hexane, 2, 5-dimethyl-2, 5-di (benzoylperoxy) hexane, 2, 5-dimethyl-2, 5-di (t-butylperoxy) hexyne-3, 1, 3-bis (t-butylperoxypropyl) benzene, di-t-butylperoxydicumyl, t-butylperoxybenzene, 2, 4-dichlorobenzoyl peroxide, 1-di-t-butylperoxy-3, 3, 5-trimethylsiloxane, and n-butyl 4, 4-di-t-butylperoxyvalerate. Among these organic peroxides, dicumyl peroxide, t-butylperoxybenzene and di-t-butylperoxydiisopropylbenzene are preferable. Further, as the sulfur-based vulcanizing agent, for example, sulfur, morpholine disulfide, or the like can be blended. Among these sulfur-based vulcanizing agents, sulfur is preferred.

As the vulcanization accelerator, sulfenamide-based, thiazole-based, thiuram-based, thiourea-based, guanidine-based, dithiocarbamate-based, aldehyde-amine-based, aldehyde-ammonia-based, or the like can be blended.

Examples of the sulfenamide compounds include sulfenamide compounds such as CBS (N-cyclohexyl-2-benzothiazylsulfenamide), TBBS (N-tert-butyl-2-benzothiazylsulfenamide), N-dicyclohexyl-2-benzothiazylsulfenamide, N-oxydiethylene-2-benzothiazylsulfenamide, and N, N-diisopropyl-2-benzothiazylsulfenamide.

Examples of the thiazole system include MBT (2-mercaptobenzothiazole), MBTS (dibenzothiazyl disulfide), sodium salt, zinc salt, copper salt, cyclohexylamine salt, 2- (2, 4-dinitrophenyl) mercaptobenzothiazole, and 2- (2, 6-diethyl-4-morpholinothio) benzothiazole.

Examples of the thiuram series include TMTD (tetramethylthiuram disulfide), tetraethylthiuram disulfide, tetramethylthiuram monosulfide, dipentamethylenethiuram disulfide, dipentamethylenethiuram monosulfide, dipentamethylenethiuram tetrasulfide, dipentamethylenethiuram hexasulfide, tetrabutylthiuram disulfide, and pentamethylenethiuram tetrasulfide.

Examples of the thiourea (thiourea) system include thiourea compounds such as thiocarbamide (thiocarbamide), diethylthiourea, dibutylthiourea, trimethylthiourea and di-o-tolylthiourea.

Examples of the guanidine compounds include guanidine compounds such as diphenylguanidine, diorthotolylguanidine, triphenylguanidine, orthotolylbiguanide, and diphenylguanidine phthalate.

Examples of the dithiocarbamate include zinc ethylphenyldithiocarbamate, zinc butylphenyldithiocarbamate, sodium dimethyldithiocarbamate, zinc diethyldithiocarbamate, zinc dibutyldithiocarbamate, zinc diamyldithiocarbamate, zinc dipropyldithiocarbamate, a complex salt of zinc pentamethylenedithiocarbamate with piperidine, zinc hexadecylisopropyldithiocarbamate, zinc octadecylisopropyldithiocarbamate, zinc dibenzyldithiocarbamate, sodium diethyldithiocarbamate, piperidine pentamethylenedithiocarbamate, selenium dimethyldithiocarbamate, tellurium diethyldithiocarbamate, cadmium diamyldithiocarbamate and the like.

Examples of the aldehyde-amine-based or aldehyde-ammonia-based compounds include acetaldehyde-aniline reactant, butylaldehyde-aniline condensate, hexamethylenetetramine, and acetaldehyde-ammonia reactant.

Stearic acid, zinc white (zinc oxide), and the like can be added as the vulcanization-accelerating assistant.

As the antioxidant, amine, phenol, imidazole compounds, metal carbamate, wax, and the like can be blended.

The softener may be a petroleum softener such as process oil, lubricating oil, paraffin, liquid paraffin, petroleum asphalt, or vaseline, or a fatty oil softener such as castor oil, linseed oil, rapeseed oil, or coconut oil; waxes such as tall oil, alternative ointment, beeswax, carnauba wax, and lanolin; and fatty acids such as linoleic acid, palmitic acid, stearic acid, and lauric acid. By blending a softening agent, the kneading processability can be further improved.

As the plasticizer, DMP (dimethyl phthalate), DEP (diethyl phthalate), DBP (dibutyl phthalate), DHP (diheptyl phthalate), DOP (dioctyl phthalate), DINP (diisononyl phthalate), DIDP (diisodecyl phthalate), BBP (butyl benzyl phthalate), DLP (dilauryl phthalate), DCHP (dicyclohexyl phthalate), anhydride phthalate, DOZ (di-2-ethylhexyl azelate), DBS (dibutyl sebacate), DOS (dioctyl sebacate), triethyl acetyl citrate, tributyl acetyl citrate, DBM (dibutyl maleate), DOM (2-ethylhexyl maleate), DBF (dibutyl fumarate), and the like can be blended.

As the anti-scorching agent, organic acids such as phthalic anhydride, salicylic acid, benzoic acid, etc.; nitroso compounds such as N-nitrosodiphenylamine, and N-cyclohexylthiophthalimide.

The rubber composition of the present invention can be produced by a known method, and can be used for various rubber products by kneading the above compounding agents using a kneader such as an open kneader like a roll or an internal kneader like a banbury mixer, and vulcanizing the mixture at 140 to 190 ℃ for 5 to 40 minutes after molding.

The rubber composition of the present invention is particularly suitable for tire applications, and can be used for various members such as a tire tread (tire tread), a tread base (under tread), a carcass (tires), a tire sidewall (side wall), and a bead portion (bead), and among these, the rubber composition is suitably used as a rubber for a tire tread in terms of more excellent wet skid resistance and abrasion resistance.

The tire of the present invention is characterized by having excellent wet skid resistance and abrasion resistance by using the rubber composition of the present invention as described above for the tread portion. The tire of the present invention is not particularly limited except that the rubber composition of the present invention is used for the tread portion, and can be appropriately configured according to a conventional method.