RU2466158C2 - Rubber mixture for tyres and pneumatic tyre - Google Patents

Abstract

FIELD: chemistry.

SUBSTANCE: rubber mixture for tyre tread rubber contains 0.1-10 pts.wt first zinc oxide particles with mean diameter of 1-150 nm per 100 pts.wt rubber component, and not more than 2.5 pts.wt second zinc oxide particles with mean diameter of at least 200 nm per 100 pts.wt rubber component. A tyre or tyre components are also made from the disclosed rubber mixture. This rubber mixture for tyres is suitable for use in making tyre tread rubber, tread base rubber, side wall filler rubber, rubber for the squeezed part and rubber for inner lining of tyres.

EFFECT: good operational characteristics of a tyre and its parts while saving resources and protecting the environment.

12 cl, 5 tbl, 21 ex, 1 dwg

Description

Technical field

The present invention relates to a rubber composition used for a tire, and more particularly, to a rubber composition for a tread of a pneumatic tire, a rubber composition for a groove of a tread, a rubber composition for a bead apex, a rubber composition for a crimp, and a rubber composition for an inner liner. The present invention also relates to a pneumatic tire including tread rubber, undercut groove rubber, bead filler rubber, crimp rubber or inner liner rubber consisting of said rubber composition.

State of the art

In general, the preparation of a rubber compound for a tire is markedly dependent on the raw materials obtained from petroleum resources. For example, a conventional passenger car tire currently on the market contains about 20% synthetic rubber, about 20% carbon black, plasticizer, synthetic fiber and the like, based on the total weight of the tire. In other words, at least 50% of the entire tire is made up of raw materials derived from petroleum resources.

For example, synthetic rubber such as butadiene rubber (BC), soot, etc. used in a rubber composition for a tire tread to improve tire grip and abrasion resistance. Soot for low rolling resistance (NSC) is added to the rubber composition for the undercut groove of the tire tread in addition to natural rubber (NK) exhibiting excellent rolling resistance. Since the stiffness of the bead apex rubber needs to be improved in order to obtain a tire having high driving stability, a large amount of soot is usually introduced into the bead apex rubber composition to improve its stiffness.

Synthetic rubber and soot are also added to the crimp rubber to provide a tire exhibiting well-balanced characteristics of excellent driving stability and stretchability.

Additionally, butyl rubber, halogenated butyl rubber or the like rubbers having excellent penetration resistance are used for the rubber of the inner liner, and soot is added to this rubber to improve bending crack resistance. Like synthetic rubbers, such as butyl rubber or halogenated butyl rubber, soot is obtained from petroleum resources.

However, in recent years special attention has been paid to environmental aspects, and carbon dioxide emissions are strictly limited. Moreover, oil reserves are limited and, therefore, raw materials derived from oil resources cannot be used unlimitedly. This awareness of environmental issues also affects the tire industry, leading to the need for rubber compounds for tires made with partial or complete replacement of currently used raw materials derived from petroleum resources with raw materials derived from non-petroleum resources. Replacing feedstocks derived from non-petroleum resources should retain at least equivalent performance or exhibit higher performance than feedstock derived from petroleum resources.

Japanese Patent Laid-Open No. 2003-63206 (Patent Document 1) discloses a tread rubber composition that uses natural rubber or epoxidized natural rubber, silicon dioxide, etc., as starting materials obtained from non-oil resources, to reduce dependence on oil resources. However, in this tread compound, abrasion resistance is not taken into account, and thus, the grip characteristic is still insufficient.

Japanese Patent Laid-Open No. 2003-55505 (Patent Document 2) describes a rubber composition containing from 0.1 to 20 parts by weight of zinc oxide having a specific surface area of at least 10 m ² / g and preferably an average particle diameter of at least at least 1 μm, per 100 mass parts of a diene rubber component. However, this rubber composition is still unsatisfactory in terms of grip and abrasion resistance.

Thus, a rubber compound for use as a tread material having excellent traction and abrasion resistance characteristics that would be obtained with starting materials obtained from resources other than petroleum and replacing materials derived from petroleum resources is not known.

While the undercut groove of the tire tread should have excellent rolling resistance and durability at high speeds, such properties were not considered in connection with the rubber composition described in the aforementioned Patent Document 1.

Japanese Patent Laid-Open No. 2003-12866 (Patent Document 3) discloses a rubber composition for a tread layer of a tread, comprising a rubber component, carbon black characterized by specific adsorption of iodine, silicon dioxide and sulfur. However, in connection with this rubber compound, durability at high speeds was also not considered.

Thus, a rubber compound having excellent low rolling resistance (NSC) and durability at high speeds, sufficiently applicable for the rubber of the trench layer of the tread, made by replacing raw materials from petroleum resources with materials from resources other than petroleum known.

Japanese Patent Laid-Open No. 2002-37929 (Patent Document 4) describes a rubber composition for a bead apex reinforced with second-hand paper, such as old newspapers, while preserving resources and protecting the environment. However, the rubber composition described in Patent Document 4 contains, along with old paper, a large amount of carbon black obtained from petroleum resources as a filler for reinforcement, and therefore conservation of resources and environmental protection are not considered as a sufficient degree. Although the stiffness of the bead apex filler can be improved due to the large amount of soot, the tire heats up easily when driving and, therefore, the durability of the tire is deteriorated due to a decrease in dynamic fatigue. Moreover, the tire rolling resistance adversely increases due to an increase in the loss tangent (tanδ).

Japanese Patent Publication No. 2005-247984 (Patent Document 5) describes a rubber composition for a crimp portion comprising carbon black including silicon dioxide and carbon black. However, the rubber composition for the crimp part, having other properties, cannot be used for the bead filler as such, since this rubber composition does not take into account tensile strength and resistance to cracking during bending.

The rubber element of the crimp portion is placed in the area of contact with the rim along the sidewall and side of the tire and is placed on a portion rubbing against the rim when the tire is mounted on the rim. The rubber element of the crimp part of the tire must have high rigidity and high resistance to thermal aging in order to transmit the driving force from the rim to the tire and withstand the load on the tire when driving. Moreover, the rubber element of the crimp part must have a high abrasion resistance to prevent abrasion that occurs during friction on the rim due to repeated deformation of the tire during movement. In addition, the stiffness, hardness and strength of the rubber element of the crimp part significantly affects the driving stability when driving.

The rubber element of the crimp portion should also have a large elongation at break (extensibility) to prevent peeling of the lower edge of the tire, which often occurs when replacing the tire.

Japanese Patent Publication No. 7-118444 (1995: Patent Document 6) proposes a solid rubber composition in which polybutadiene rubber containing at least 5% by weight is used. syndiotactic crystals, as the rubber compound used for the rubber element of the crimp part, which must have excellent properties. Japanese Patent Publication No. 7-81335 (1995: Patent Document 7) describes a rubber element of an on-board tape consisting of a composite rubber tape prepared by bonding several types of rubber components having different mixture ratios and characteristics with respect to each other. However, in the manufacture of the multilayer rubber element of the crimp part or the side tape, the production stages are complicated, which leads to high cost.

Japanese Patent Publication No. 2000-198883 (Patent Document 8) describes a rubber composition for a tire tread in which a low rolling resistance and a high abrasion resistance are achieved by adding a certain amount of carbon black based material containing silicon dioxide. If this technology is used for a rubber part of a crimp part that requires high rigidity and high hardness, driving stability and tensile properties cannot be improved in a well-balanced way. In the aforementioned Patent Document 5, a rubber composition for a crimp portion comprising carbon black comprising silica and carbon black is described. However, this rubber composition still does not have sufficient tensile strength and abrasion resistance.

The inner liner is a rubber element forming the inner surface of a pneumatic tire, in particular a tubeless tire, to hold the tire internal pressure. Although the rubber element of the inner liner should have excellent resistance to penetration of air and resistance to cracking during bending, neither resistance to penetration of air nor resistance to cracking during bending was considered in connection with the aforementioned rubber composition according to Patent Document 1.

Japanese Patent Publication No. 2005-26114 (Patent Document 9) describes a rubber composition made by dispersing a certain amount of zinc oxide in a rubber component containing halogenated butyl rubber and / or isobutylene-p-methyl styrene copolymer halide and forming an internal rubber compound from this rubber composition gaskets, and it is also described that the caliber of the rubber composition for an internal gasket or similar product can be kept thin, and the mass of the tire can be reduced without reducing viscosity. However, they did not consider ways to jointly achieve resistance to air penetration and resistance to cracking when bending the rubber of the inner liner.

Thus, in connection with the rubber mixture prepared from raw materials obtained from resources other than petroleum, replacing materials derived from petroleum resources, a rubber mixture having excellent penetration resistance to air and cracking resistance to bending is sufficiently known Applicable as a material for indoor installation.

Patent Document 1: Published Japanese Patent No. 2003-63206

Patent Document 2: Published Japanese Patent No. 2003-55505

Patent Document 3: Published Japanese Patent No. 2003-12866

Patent Document 4: Published Japanese Patent No. 2002-37929

Patent Document 5: Published Japanese Patent No. 2005-247984

Patent Document 6: Published Japanese Patent No. 7-118444

Patent Document 7: Published Japanese Patent No. 7-81335

Patent Document 8: Japanese Published Patent No. 2000-198883

Patent Document 9: Japanese Published Patent No. 2005-264114

Description of the invention

Objectives of the invention

The present invention has been proposed to solve the aforementioned problems, and therefore, its purpose is to provide a rubber composition for a tire having a high content of raw materials derived from non-petroleum resources, taking into account, compared with the prior art, considerations of resource conservation and environmental protection medium, and exhibiting excellent performance and satisfying the characteristics required for each part, whether it is used for the tread, the undercut groove of the tread, side filler, crimp, or inner liner.

Another objective of the present invention is the provision of a pneumatic tire, including tread rubber, rubber of the under-tread layer of the tire, rubber of the bead filler, rubber of the crimping part, or rubber of the inner liner, consisting of said rubber mixture.

Means for solving the problems of the invention

The present invention provides a rubber composition for a tire containing from 0.1 to 10 parts by mass of zinc oxide particles having an average diameter of not more than 200 nm per 100 parts by mass of the rubber component. The rubber composition for a tire of the present invention is suitably used for the manufacture of tread rubber, tread rubber of a tread layer, rubber of a bead apex rubber, crimp rubber and rubber of a tire inner liner.

If the rubber composition of the present invention is a rubber composition used for the manufacture of tread rubber (hereinafter referred to as the tread rubber composition), the rubber component preferably contains epoxidized natural rubber (ENC). The tread rubber composition of the present invention preferably further comprises from 60 to 90 parts by mass of silicon dioxide per 100 parts by mass of the rubber component.

If the rubber composition of the present invention is a rubber composition used to make the rubber of the under-tread layer of the tread (hereinafter referred to as the rubber composition for the under-tread layer of the tread), the rubber component preferably contains natural rubber (NR). The rubber composition for the under-tread tread layer of the present invention preferably further comprises 30 to 50 parts by mass of silica per 100 parts by mass of the rubber component.

If the rubber composition of the present invention is a rubber composition used for the manufacture of bead apex rubber (hereinafter referred to as a bead apex rubber), the rubber component preferably contains at least natural rubber and preferably essentially consists only of natural rubber. The rubber composition for a bead apex according to the present invention preferably further comprises from 15 to 90 parts by mass of silica per 100 parts by mass of natural rubber.

If the rubber composition of the present invention is a rubber composition used to make the rubber of the crimp part (hereinafter referred to as the rubber composition for the crimp part), the rubber component preferably contains from 30 to 90% of the mass. natural rubber and from 10 to 70% of the mass. epoxidized natural rubber. The rubber composition for the crimp part of the present invention preferably further comprises from 15 to 90 parts by mass of silicon dioxide per 100 parts by mass of the rubber component.

If the rubber composition of the present invention is a rubber composition used for the manufacture of rubber for the inner liner (hereinafter referred to as the rubber compound for the inner liner), the rubber component preferably contains epoxidized natural rubber (ENC). The rubber composition for the inner liner of the present invention preferably further comprises from 30 to 50 parts by mass of silicon dioxide per 100 parts by mass of the rubber component.

The present invention also provides a pneumatic tire comprising tread rubber, a groove rubber of a tread, bead apex rubber, crimp rubber or an inner liner rubber consisting of said rubber composition.

The technical result of the invention

The present invention provides a rubber composition for a tire having a high content of materials derived from non-petroleum resources compared with the prior art, taking into account largely resource conservation and environmental considerations, and exhibiting excellent performance that meets the specifications required for each part, whether it is used for the tread, the undercut of the tread, the bead filler, the crimp part or the inner liner, and the invention provides a pneumatic tire comprising tread rubber, rubber of the under-tread layer of the tire, rubber of the bead filler, rubber of the crimping part or rubber of the inner liner, consisting of said rubber mixture.

Brief Description of the Drawings

1 is a schematic sectional view of an example of a pneumatic tire of the present invention.

Description of symbols

1 - tire; 2 - tread; 2a - treadmill; 2b is an undercut tread layer; 3 - sidewall; 4 - board; 5 - the bead core; 6 - frame; 7 - belt belt; 8 - rubber filler side; 9 - rubber inner lining; 3G - sidewall tires; 4G - rubber crimp part.

The best way to implement the invention

The rubber composition for a tire of the present invention contains from 0.1 to 10 parts by mass of zinc oxide particles having an average diameter of not more than 200 nm per 100 parts by mass of the rubber component. The rubber composition for a tire of the present invention is suitably used as a rubber composition for a tread, a rubber composition for a trench layer of a tread, a rubber composition for a bead apex, a rubber composition for a crimp, and a rubber composition for an inner liner. These rubber compounds are described in more detail below.

Rubber compound for a protector

The rubber composition for the tread of the present invention contains from 0.1 to 10 parts by mass of zinc oxide particles having an average diameter of not more than 200 nm per 100 parts by mass of the rubber component. This tread rubber composition of the present invention gives the tire excellent grip and abrasion resistance.

Rubber component

At least one rubber component selected from natural rubber (NK), epoxidized natural rubber (ENC), deproteinized natural rubber (DPNK) and other natural rubber, as well as diene-based synthetic rubber, are incorporated into the tread rubber composition according to the present invention.

If the rubber composition for the tread of the present invention contains natural rubber (NK), the content of natural rubber (NK) in the rubber component is not particularly limited, and it can be, for example, at least about 5% by weight. If the rubber mixture contains as a rubber component rubber on a natural basis other than NK, the content of natural rubber can be less than at least about 5% of the mass. If natural rubber other than NK is present as the rubber component, the rubber mixture may not contain NK. On the other hand, if the rubber composition for the tread contains only NK as a natural-based rubber component, the NK content in the rubber component is preferably at least 90% by weight, more preferably at least 95% by weight. If the content of the oil is less than 90% of the mass., In the rubber compound decreases the proportion of resources other than oil.

Natural rubber (NR) can be obtained, for example, from materials of grades RSS # 3, TSR20 or SIR20, commonly used in the rubber industry.

The tread rubber composition of the present invention preferably contains epoxidized natural rubber (ENC) as a rubber component. Epoxidized natural rubber (ENC) is prepared by epoxidizing unsaturated double bonds of natural rubber, and the adhesion of its molecules is improved due to epoxy groups, which are polar groups. Therefore, epoxidized natural rubber has a higher glass transition temperature (TSTK) than natural rubber and has excellent mechanical strength, abrasion resistance, and air penetration resistance. In particular, when silicon dioxide is introduced into the rubber composition, mechanical and abrasion strengths can be achieved that are substantially equal to these values for soot-containing rubber mixtures due to reactions between silanol groups on the surface of silicon dioxide and epoxy groups of epoxidized natural rubber.

Epoxidized natural rubber (ENC) can be obtained from commercially available material or by epoxidation of natural rubber (NR). The method for epoxidation of nanocrystals is not particularly limited, and chlorohydrin synthesis, direct oxidation, a method using hydrogen peroxide, a method using alkyl hydroperoxide, a peracid method, or the like can be used. As the peracid method, a method of reacting an organic peracid, such as peracetic acid or per formic acid, with natural rubber can be used.

The degree of epoxidation of epoxidized natural rubber (ENC) is preferably at least 5 mol%, more preferably at least 10 mol%. If the degree of epoxidation of the ENC is less than 5 mol%, the effect of improving the adhesion characteristics of the road surface is reduced. Moreover, the degree of epoxidation of epoxidized natural rubber (ENC) is preferably not more than 60 mol%, more preferably not more than 55 mol%. If the degree of epoxidation of the ENC exceeds 60 mol%, the strength of the obtained tread rubber is insufficient and the ability to connect with general-purpose rubber is reduced. In this description, the degree of epoxidation of epoxidized natural rubber (ENC) is expressed as the following ratio: (number of epoxidized double bonds) / (number of non-epoxidized double bonds) × 100%.

If the rubber composition for the tread of the present invention contains epoxidized natural rubber (ENC), the content of ENC in the rubber component can be set, for example, at least about 5% of the mass. If the rubber composition contains as a rubber component rubber on a natural basis other than ENC, the content of ENC may be less than about 5% of the mass. On the other hand, if the rubber composition for the tread contains only ENC as a natural-based rubber component, the content of ENC in the rubber component is preferably at least 90% by weight, more preferably at least 95% by weight. If the content of ENC is less than 90% by mass, then the proportion of resources other than petroleum in the rubber compound decreases.

The proportion of ENC in the natural-based rubber component introduced into the rubber composition is preferably higher, and may be, for example, at least 50% by weight, more preferably at least 70% by weight, even more preferably at least 90% by weight . The effect of improving the grip performance can be further improved by increasing the proportion of ENC in the natural-based rubber component. The rubber composition for the tread of the present invention may contain only ENC as a rubber component. In this way, the grip power of the tread is improved and excellent driving stability can be obtained.

The tread rubber composition of the present invention may contain deproteinized natural rubber (DPNA) as a rubber component. As a rule, natural rubber (NK) contains from about 5 to 10% of the mass. non-rubber constituents such as protein and lipid. These non-rubber constituents, in particular protein, are considered responsible for the entanglement of molecular chains leading to gelation. In order to solve this problem, deproteinized natural rubber (DPNC), obtained by eliminating non-rubber components from natural rubber, is especially successfully introduced into the rubber compound.

The average molecular weight (determined by gel permeation chromatography (GPC) in terms of polystyrene) of deproteinized natural rubber (DPNA) is preferably at least 1400000. If the average molecular weight is less than 1400000, the strength of the crude rubber is reduced. The nitrogen content in deproteinized natural rubber (DPNA) is preferably not more than 0.1% by mass, more preferably not more than 0.08% by mass, even more preferably not more than 0.05% by mass. If the nitrogen content exceeds 0.1 mass%, this causes an adverse gelation. The nitrogen content in deproteinized natural rubber (DPNA) is measured by the IICM method (Institute of Rubber Research of Malaysia).

If the rubber composition for the tread of the present invention contains deproteinized natural rubber (DPC), the content of deproteinized natural rubber (DPC) in the rubber component is not particularly limited, however, it can be, for example, at least about 5% by weight. If the rubber composition contains as a rubber component rubber on a natural basis other than DPNK, the content of DPNK can be less than about 5% of the mass. If natural rubber other than DPNK is present as the rubber component, the rubber composition may not contain DPNK. On the other hand, if the rubber composition for the tread contains only DPNK as a rubber component on a natural basis, the content of DPNK in the rubber component is preferably at least 90% by weight, more preferably at least 95% by weight. If the content of DPNK is less than 90% by mass, the proportion of non-oil resources in the rubber composition decreases and the abrasion resistance decreases.

Deproteinized natural rubber (DPNA) can be obtained by deproteinization of natural rubber (NR). Natural rubber (NR) can be deproteinized, for example, by any of the following methods.

(1) A method for decomposing a protein by adding a proteolytic enzyme or bacteria to natural rubber latex.

(2) A method for decomposing a protein by adding alkali to natural rubber latex and heating the mixture.

(3) A method for releasing a protein adsorbed by natural rubber latex using a surfactant.

Natural rubber latex used for deproteinizing treatment is not particularly limited, and milky juice, ammonia stabilized latex, or the like can be used.

Although the proteolytic enzyme used in the aforementioned method (1) can be obtained from a well-known material, and it is not particularly limited, suitable, for example, protease or similar enzymes are suitable. A protease can be obtained either from bacteria or from yeast, with a protease derived from bacteria being preferred. Moreover, other enzymes such as lipase, esterase, amylase, laccase or cellulase can also be used.

If an alkaline protease is used as a proteolytic enzyme, its activity is preferably from 0.1 to 50 APU / g (protease activity, units per gram), more preferably from 1 to 25 APU / g. The activity of the proteolytic enzyme is measured by a variation of Anson's hemoglobin method (Anson, M.L., J. Gen. Physiol., 22, 79 (1938)). The proteolytic enzyme is reacted in a solution selected in such a way that the final concentration of urea denatured hemoglobin used as a substrate is 14.7 mg / ml at 25 ° C and pH 10.5 for 10 minutes, and then added to trichloroacetic acid to the reacted solution such that the final concentration is 31.25 mg / ml. Then, the soluble part of trichloroacetic acid is stained with a phenolic reagent, and the activity per 10-minute reaction is obtained by means of a calibration curve that sets the degree of staining of 1 mole of tyrosine as 1 APU, and the resulting activity is given for 1 minute. 1 APE. corresponds to the amount of protease providing the same degree of staining of the soluble part of trichloroacetic acid as for 1 mole of tyrosine stained with a phenolic reagent.

The content of the proteolytic enzyme, suitably set in accordance with the activity of the enzyme, is usually from 0.0001 to 20 mass parts, preferably from 0.001 to 10 mass parts per 100 mass parts of the natural rubber latex solid. It is possible that the protein contained in natural rubber latex will not decompose sufficiently if the content of the proteolytic enzyme is less than 0.0001 mass parts, while the activity of the enzyme decreases and the cost increases if the content exceeds 20 mass parts.

The processing time of the proteolytic enzyme is not particularly limited, and can be appropriately set in accordance with the activity of the enzyme. In general, the processing time is preferably from a few minutes to about one week. During treatment with the proteolytic enzyme, natural rubber latex can either be mixed or not mixed. Moreover, if necessary, the processing temperature can be controlled, and the appropriate processing temperature is from 5 to 90 ° C, preferably from 20 to 60 ° C. The enzyme quickly loses activity if the processing temperature exceeds 90 ° C, while the reaction of the enzyme proceeds slowly if the processing temperature is less than 5 ° C.

For example, at least one or two anionic surfactants, a nonionic surfactant, and an amphoteric surfactant can be used as a surfactant used in the aforementioned method (3). For example, a carboxylic acid based surfactant, a sulfonic acid, sulfate or phosphate based surfactant may be listed as an anionic surfactant. For example, a polyoxyalkylene ester-based surfactant, a polyoxyalkylene ester-based ester, a polyhydric alcohol and a fatty acid-based surfactant, a sucrose ester with a fatty acid, or an alkyl polyglucoside-based is suitably used as a nonionic surfactant. For example, an amino acid type, betaine type or amine oxide type surfactant can be listed as an amphoteric surfactant.

In the above method (3), the protein adsorbed by natural rubber latex is released by washing the natural rubber latex with a surfactant. Natural rubber latex can be washed with a surfactant, either in a state still untreated by the enzyme or in a state completely treated with the enzyme. More specifically, natural rubber latex that has not yet been processed or has been completely treated with an enzyme can be washed by adding a centrifugal surfactant to it, or by aggregating and separating particles of natural rubber latex. Centrifugation can be performed one or more times. Typically, deproteinized natural rubber latex, from which protein is highly removed, can be obtained by centrifugation. Centrifugation can be carried out after dilution of the natural rubber latex so that the content of the rubber component is from 5 to 40% by weight, preferably from 10 to 30% by weight.

The surfactant content is from 0.001 to 20 parts by mass, preferably from 0.001 to 15 parts by mass per 100 parts by mass of the solid in natural rubber latex.

When a proteolytic enzyme or surfactant is used in the aforementioned method (1) or (3), other additives, for example, such as a pH adjuster or dispersing agent, can be added.

The pH adjuster can be obtained, for example, from a phosphate such as potassium dihydrogen phosphate, potassium hydrogen phosphate, sodium dihydrogen phosphate or sodium hydrogen phosphate; an acetate such as potassium acetate or sodium acetate; acids such as sulfuric acid, acetic acid, hydrochloric acid, nitric acid, citric acid or succinic acid, or their salts; ammonia; potassium hydroxide, sodium hydroxide; sodium carbonate or sodium bicarbonate. Typically, the content of the pH regulator is from 0.01 to 0.5 mass parts per 100 mass parts of solid rubber in natural rubber latex.

The dispersing agent can be obtained, for example, from a copolymer of styrene and sulfonic acid, a condensation product of naphthalene sulfonic acid and formalin, lignosulfonic acid, a copolymer of a polycyclic aromatic compound and sulfonic acid, acrylic acid, a homopolymer or a copolymer of maleic anhydride or a copolymer of isobutylene and acrylic acid isobutamide and isobutamide.

The deproteinized natural rubber latex obtained by the above method can be coagulated after removal or without removal of non-rubber components by centrifugation or the like. The coagulation method is not particularly limited, and deproteinized natural rubber latex can be coagulated in a well-known manner. In general, deproteinized natural rubber latex is coagulated by the method of labilization and coagulation of rubber latex particles by adding an acid such as formic acid or sulfuric acid, or a salt such as sodium chloride, or by the method of labilization and coagulation of rubber latex particles by passing a cloud point of a surfactant .

The gel content in deproteinized natural rubber is preferably not more than 10% of the mass. If the gel content exceeds 10 mass%, the viscosity of unvulcanized rubber is reduced and the processability is reduced. The gel content is measured as a fraction insoluble in toluene.

The tread rubber composition of the present invention may further comprise another modified natural rubber other than the above, or a diene-based synthetic rubber. Synthetic rubber based on diene can be obtained, for example, from styrene butadiene rubber (BSK), butadiene rubber (BC), isoprenstyrene copolymer rubber, isoprene rubber (IR), isobutylene isoprene rubber (IIC), chloroprene rubber (HCR), acryl nitride (CKB), , halogenated isobutylene isoprene rubber (G-IIC) or a halide of a copolymer of isobutylene and p-methylstyrene.

If the rubber composition for the tread of the present invention contains a diene-based synthetic rubber, the content of the diene-based synthetic rubber in the rubber component is preferably set to not more than 10% by weight. The tread rubber composition of the present invention is more preferably free of diene-based synthetic rubber in order to increase the content of non-petroleum resources for reasons of resource conservation and environmental protection.

Zinc oxide

The rubber composition for the tread of the present invention contains zinc oxide particles having an average diameter of not more than 200 nm. In the present invention, the average particle diameter of zinc oxide is measured by scattering a laser beam using an apparatus manufactured by Shimadzu Corporation to measure the diameter distribution of the nanoparticles.

Zinc oxide is introduced into the rubber composition for the tread of the present invention as an additional vulcanization accelerator. When the tread rubber composition of the present invention contains zinc oxide particles having an average particle diameter of not more than 200 nm, it is possible to prevent the formation of cracks caused by zinc oxide, and the adhesion property to the road surface and the abrasion resistance of the obtained tread rubber can be improved. If the average particle diameter of the zinc oxide exceeds 200 nm, the particles can serve as starting points for cracking, and the adhesion characteristics of the road surface and the abrasion resistance of the obtained tread rubber cannot be sufficiently improved. In order to further improve the road grip characteristic and abrasion resistance, the average particle diameter of the zinc oxide is preferably not more than 150 nm, more preferably not more than 100 nm. Moreover, the average particle diameter of zinc oxide is preferably at least less than 1 nm, more preferably at least 10 nm. If the average particle diameter of the zinc oxide is less than 1 nm, the dispersibility of the zinc oxide in the rubber composition is deteriorated.

Zinc oxide is a non-petroleum resource, and a rubber compound for a tire containing zinc oxide can be considered an environmentally friendly rubber compound, taking into account conservation of resources and environmental protection.

The content of zinc oxide particles having an average diameter of not more than 200 nm is at least 0.1 mass parts, preferably at least 0.5 mass parts, more preferably at least 1.0 mass parts per 100 mass parts of the rubber component . If the content of zinc oxide particles having an average diameter of not more than 200 nm is less than 0.1 mass parts, the effect of zinc oxide, which serves as an additional vulcanization accelerator, becomes difficult to achieve. Moreover, the content of zinc oxide particles having an average diameter of not more than 200 nm is not more than 10 mass parts, preferably not more than 2.5 mass parts per 100 mass parts of the rubber component. If the content of zinc oxide particles having an average diameter of not more than 200 nm exceeds 10 mass parts, the abrasion resistance is reduced.

The tread rubber composition of the present invention may further comprise zinc oxide particles having an average diameter of at least 200 nm, along with zinc oxide particles having an average diameter of not more than 200 nm. However, the content of zinc oxide particles having an average diameter of at least 200 nm is preferably not more than 2.5 mass parts, more preferably not more than 1.5 mass parts per 100 mass parts of the rubber component. If the content of zinc oxide particles having an average diameter of at least 200 nm exceeds 2.5 mass parts, then the abrasion resistance deteriorates. If the rubber composition for the tread of the present invention further comprises zinc oxide particles having an average diameter of at least 200 nm, the ratio (mass ratio) of zinc oxide particles having an average diameter of at least 200 nm to zinc oxide particles having an average diameter not more than 200 nm, preferably not more than 5, more preferably not more than 3. If this ratio exceeds 5, the abrasion resistance deteriorates.

Silica

The tread rubber composition of the present invention preferably further comprises silicon dioxide. Silicon dioxide acts as a reinforcing filler, and the abrasion resistance of the obtained tread rubber can be improved by introducing silicon dioxide into the tread rubber composition.

Silicon dioxide can be obtained either wet or dry.

The BET specific surface area of the silica is preferably at least 100 m ² / g, more preferably at least 120 m ² / g. If the BET specific surface area of silicon dioxide is less than 100 m ² / g, the reinforcing effect is insufficient. Moreover, the BET specific surface area of the silica is preferably not more than 300 m ² / g, more preferably not more than 280 m ² / g. If the BET specific surface area of silicon dioxide exceeds 300 m ² / g, the dispersibility decreases and the exothermicity of the tread rubber increases.

If the rubber composition for the tread of the present invention contains silicon dioxide, the silicon dioxide content is preferably at least 60 parts by mass, more preferably at least 70 parts by mass per 100 parts by mass of the rubber component. If the silica content is less than 60 parts by mass, it is not possible to achieve a satisfactory abrasion resistance. Moreover, the content of silicon dioxide is preferably not more than 90 mass parts, more preferably not more than 80 mass parts per 100 mass parts of the rubber component. If the silica content exceeds 90 parts by mass, it is not possible to achieve excellent rolling resistance.

Silane Coupling Agent

The tread rubber composition of the present invention, if it contains silicon dioxide, preferably contains a silane coupling agent along with silicon dioxide. A silane coupling agent can be prepared from a well-known silane coupling agent, such as a sulfide-based silane coupling agent, for example

bis (3-triethoxysilylpropyl) tetrasulfide,

bis (2-triethoxysilylethyl) tetrasulfide,

bis (4-triethoxysilylbutyl) tetrasulfide,

bis (3-trimethoxysilylpropyl) tetrasulfide,

bis (2-trimethoxysilylethyl) tetrasulfide,

bis (4-trimethoxysilylbutyl) tetrasulfide,

bis (3-triethoxysilylpropyl) trisulfide,

bis (2-triethoxysilylethyl) trisulfide,

bis (4-triethoxysilylbutyl) trisulfide,

bis (3-trimethoxysilylpropyl) trisulfide,

bis (2-trimethoxysilylethyl) trisulfide,

bis (4-trimethoxysilylbutyl) trisulfide,

bis (3-triethoxysilylpropyl) disulfide,

bis (2-triethoxysilylethyl) disulfide, bis (4-triethoxysilyl butyl) disulfide,

bis (3-trimethoxysilylpropyl) disulfide,

bis (2-trimethoxysilylethyl) disulfide,

bis (4-trimethoxysilylbutyl) disulfide, 3-trimethoxysilylpropyl-N, N-dimethylthiocarbamoyl tetrasulfide, 3-triethoxysilylpropyl-N, N-dimethylthiocarbamoyl tetrasulfide, 2-trimethoxysilylethyl-N, n-dimethylamide

3-trimethoxysilylpropylbenzothiazolyltetrasulfide,

3-triethoxysilylpropylbenzothiazole tetrasulfide or

3-trimethoxysilylpropylmethacrylate monosulfide; a mercaptan-based silane coupling agent, for example 3-mercaptopropyltrimethoxysilane, 3-mercaptopropyltriethoxysilane, 2-mercaptoethyltrimethoxysilane or 2-mercaptoethyltriethoxysilane; vinyl-based silane coupling agent, for example vinyltriethoxysilane or vinyltrimethoxysilane; an amine-based silane coupling agent, for example 3-aminopropyltriethoxysilane, 3-aminopropyltrimethoxysilane, 3- (2-aminoethyl) aminopropyltriethoxysilane or 3- (2-aminoethyl) aminopropyltrimethoxysilane; a silane coupling agent containing a glycidoxy group, for example γ-glycidoxypropyltriethoxysilane, γ-glycidoxypropyltrimethoxysilane, γ-glycidoxypropylmethyldiethoxysilane or γ-glycidoxypropylmethyldimethoxysilane; a silane coupling agent containing a nitro group, for example 3-nitropropyltrimethoxysilane or 3-nitropropyltriethoxysilane, or a chlorine-based silane coupling agent, for example 3-chloropropyltrimethoxysilane, 3-chloropropyltriethoxysilane, 2-chloroethyltrimethoxysilane or 2-chloroethyl. Such silane coupling agents may be used independently of one another, or at least two such silane coupling agents may be used in combination.

In particular, Si69 (bis (3-triethoxysilylpropyl) tetrasulfide) or Si266 (bis (3-triethoxysilylpropyl) disulfide) manufactured by Degussa GmbH is preferably used because of their excellent processability.

The content of the silane coupling agent is preferably at least 1 mass part, more preferably at least 2 mass parts per 100 mass parts of silica. If the content of the silane coupling agent is less than 1 mass part, the effect of improving dispersibility, etc. becomes insufficient. Moreover, the content of the silane coupling agent is preferably not more than 20 parts by mass, more preferably not more than 15 parts by mass per 100 parts by mass of silica. If the content of the silane coupling agent exceeds 20 parts by mass, a sufficient binding effect is not achieved, and the reinforcing effect and abrasion resistance are reduced.

The tread rubber composition of the present invention may contain carbon black. The BET specific area of carbon black is preferably at least 70 m ² / g, more preferably at least 80 m ² / g. If the specific surface area according to the BET of the carbon black is less than 70 m ² / g, the reinforcing effect is insufficient. Moreover, the BET specific surface area of the carbon black is preferably not more than 200 m ² / g, more preferably not more than 180 m ² / g. If the specific surface area according to the BET of the carbon black exceeds 200 m ² / g, the reinforcing effect is reduced.

The dibutyl phthalate oil number of carbon black is preferably at least 70 ml / 100 g, more preferably 80 to 160 ml / 100 g. If the dibutyl phthalate oil number of carbon black is less than 70 ml / 100 g, the enhancing effect is reduced.

If the rubber composition for the tread of the present invention contains carbon black, the carbon black content is preferably 5 to 150 parts by mass, more preferably 10 to 120 parts by mass, even more preferably 15 to 100 parts by mass per 100 parts by mass of the rubber component. A significant decrease in exothermicity and an improvement in grip performance due to the addition of soot cannot be achieved if the soot content is less than 5 parts by mass, while manufacturability and usability are reduced if the soot content exceeds 150 parts by mass. However, the rubber composition for the tread of the present invention preferably does not contain soot, for reasons of conservation of resources and environmental protection.

Other additives

The tread rubber composition of the present invention may additionally contain, in addition to the above components, other additives, for example, a curing agent, a vulcanization accelerator, stearic acid, metal stearate, oil, a cured resin, wax, an antioxidant and similar additives commonly used in rubber industry.

As the curing agent, for example, organic peroxide or a sulfur-based curing agent can be used. Organic peroxide can be obtained, for example, from benzoyl peroxide, dicumyl peroxide, di-tert-butyl peroxide, tert-butyl cumyl peroxide, methyl ethyl ketone peroxide, cumene hydroperoxide, 2,5-dimethyl-2,5-di (tert-butyl peroxy) hexane, 2,5-dimethyl- 2,5-di (benzoylperoxy) hexane, 2,5-dimethyl-2,5-di (tert-butylperoxy) hexin-3 or 1,3-bis (butylperoxypropyl) benzene, di-tert-butylperoxy-diisopropylbenzene, tert- butyl peroxybenzene, 2,4-dichlorobenzoyl peroxide, 1,1-di-tert-butyl peroxy-3,3,5-trimethylsiloxane or n-butyl-4,4-di-tert-butyl peroxyvalerate. Particularly preferred are dicumyl peroxide, tert-butyl peroxybenzene or di-tert-butyl peroxy-diisopropylbenzene. A sulfur-based vulcanizing agent can be obtained, for example, from sulfur or morpholine disulfide. Especially preferred is sulfur. Such curing agents can be used independently of each other, or at least two curing agents can be used in combination. Sulfur can be treated with oil.

The vulcanization accelerator may comprise at least one of sulfenamide-based vulcanization accelerators, thiazole-based, thiuram-based, thiourea-based, guanidine-based, dithiocarbamate-based, aldehyde-based or aldehyde-ammonia-based, imidazoline-based and xanthate-based . A sulfenamide-based vulcanization accelerator can be obtained, for example, from CVS (N-cyclohexyl-2-benzothiazyl sulfenamide), TBBS (N-tert-butyl-2-benzothiazyl sulfenamide), N, N-dicyclohexyl-2-benzothiazyl sulfenamide, N-oxide -benzothiazylsulfenamide or N, N-diisopropyl-2-benzothiazolsulfenamide. A thiazole-based vulcanization accelerator can be obtained, for example, from sodium salt, zinc salt, copper salt or cyclohexylamine salt of MBT (2-mercaptobenzothiazole), MBTS (dibenzothiazyl disulfide) or 2-mercaptobenzothiazole, or a thiazole-based compound such as 2- (2 , 4-dinitrophenyl) mercaptobenzothiazole or 2- (2,6-diethyl-4-morpholintio) benzothiazole. A thiuram-based vulcanization accelerator can be obtained, for example, from thiuram-based compounds, such as TMTD (tetramethylthiuram disulfide), tetraethyl thiuram disulfide, dipentamethylentiuram disulfide, dipentamethylentiuram disulfide tetramethylumethimenti diphenylmethylenti diphenylmethylenediamine dimethyl-dimethyl-dimethyl-dimethyl-dimethyl-dimethyl-dimethyl-dimethyl-dimethane A thiourea-based vulcanization accelerator can be obtained, for example, from thiocarbamide, diethylthiourea, dibutylthiourea, trimethylthiourea or diorthotolultiurea. The guanidine-based vulcanization accelerator can be obtained, for example, from diphenylguanidine, diorthotolyl guanidine, triphenyl guanidine, ortotolyl biguanidine or diphenyl guanidine. Vulcanization accelerator based dithiocarbamate may be prepared, for example, dithiocarbamate compounds such as ethylphenyldithiocarbamate, zinc butilfenilditiokarbamat zinc, sodium dimethyldithiocarbamate, zinc dimethyldithiocarbamate, zinc diethyldithiocarbamate, zinc dibutyldithiocarbamate, diamyldithiocarbamate, zinc dipropyldithiocarbamate, zinc complex salt of zinc pentamethylenedithiocarbamate and piperidine, hexadecyl (or octadecyl) zinc isopropyl dithiocarbamate, zinc dibenzyl dithiocarbamate, sodium diethyl dithiocarbamate, penta etilenditiokarbamat piperidine, selenium dimethyldithiocarbamate, tellurium diethyldithiocarbamate, and cadmium diamyldithiocarbamate. The aldehydeamine or aldehyde ammonia vulcanization accelerator can be obtained, for example, from an aldehydeamine or aldehyde ammonia compound, such as the reaction product of acetaldehyde and aniline, the condensation product of butylaldehyde and aniline, hexamethylenetetramine or the reaction product of acetaldehyde and ammonia. An imidazoline-based vulcanization accelerator can be obtained, for example, from an imidazoline-based compound, such as 2-mercaptoimidazoline. A xanthate-based vulcanization accelerator can be obtained, for example, from a xanthate-based compound such as zinc dibutylxanthate. Such vulcanization accelerators can be used independently of each other, or at least two types of vulcanization accelerators can be used in combination.

The antioxidant can be appropriately selected from amine based, phenol based, imidazole based and metal carbamate based salts.

The tread rubber composition of the present invention may comprise metal stearate. Metal stearate can be obtained from magnesium stearate, magnesium 12-hydrostearate, calcium stearate, calcium 12-hydrostearate, barium stearate, barium 12-hydrostearate, zinc stearate or zinc 12-hydrostearate. In particular, the metal stearate is preferably prepared from alkali or alkaline earth metal stearate, more preferably calcium stearate, calcium 12-hydrostearate, barium stearate or barium 12-hydrostearate, for reasons of improving heat resistance and compatibility with epoxidized natural rubber.

The content of the metal stearate is at least 1 mass part, preferably at least 1.5 mass parts per 100 mass parts of the rubber component. If the content of the metal stearate is less than 1 mass part, sufficient effects of improving compatibility and heat resistance may not be achieved. In addition, the content of metal stearate is not more than 10 mass parts, preferably not more than 8 mass parts. If the content of metal stearate exceeds 10 mass parts, the hardness and elastic moduli are reduced, and the abrasion resistance is also reduced.

Rubber compound for undercut tread

The rubber composition for the tread layer of the tread of the present invention contains from 0.1 to 10 parts by mass of zinc oxide particles having an average diameter of not more than 200 nm per 100 parts by mass of the rubber component. This rubber mixture for the undercut groove of the present invention gives the tire excellent low rolling resistance (NSC) and durability at high speeds.

Rubber component

At least one rubber component selected from natural rubber (NK), epoxidized natural rubber (ENC), deproteinized natural rubber (DPNK) and other natural-based rubber, as well as diene-based synthetic rubber, are incorporated into the rubber composition for the sub-groove tread layer of the present invention. In particular, the rubber composition for the undercut groove of the tread of the present invention preferably contains natural rubber (NK) as a rubber component. When the rubber composition for the undercut groove of the tread of the present invention contains NK, low rolling resistance (NK) can be further reduced.

If the rubber mixture for the undercut groove of the tread of the present invention contains natural rubber (NK), the NK content in the rubber component can be, for example, at least 5% by weight. If the rubber mixture for the undercut groove of the tread of the present invention contains natural rubber other than NK as the rubber component, the NK content may be less than about 5% by weight. On the other hand, if the rubber composition for the undercut groove of the tread contains only NK as a natural-based rubber component, the NK content in the rubber component is preferably at least 90% by weight, more preferably at least 95% by weight. If the content of the oil is less than 90% of the mass., In the rubber compound decreases the proportion of resources other than oil.

In addition, the content of NK in the natural-based rubber component introduced into the rubber composition for the undercut groove of the tread is preferably higher and, for example, at least 50 wt.%, More preferably at least 70 wt. , even more preferably at least 90% of the mass. The effect of reducing rolling resistance can be further enhanced by increasing the proportion of NK in the natural-based rubber component. The rubber composition for the undercut groove of the tread of the present invention may contain only NK as a rubber component. Thus, low rolling resistance is further reduced, and excellent driving stability can be achieved.

Natural rubber (NR) can be obtained, for example, from materials of grades RSS # 3, TSR20 or SIR20, commonly used in the rubber industry.

The rubber composition for the under-tread tread layer of the present invention may contain the aforementioned epoxidized natural rubber (ENC) as a rubber component. If the rubber mixture for the undercut groove of the tread contains epoxidized natural rubber (ENC), the content of ENC in the rubber component is not particularly limited, and at least about 5% by weight can be set. However, if the rubber composition for the under-groove tread layer of the present invention contains natural rubber other than ENC as the rubber component, the ENC content may be less than about 5% by weight. On the other hand, if natural rubber other than ENC is present as the rubber component, the rubber composition for the tread layer of the tread of the present invention may not contain ENC. On the other hand, if the rubber composition for the under-tread tread layer of the present invention contains only ENC as a natural-based rubber component, the content of ENC in the rubber component is preferably at least 90% by weight, more preferably at least 95% by weight. If the content of ENC is less than 90% by mass, then the proportion of resources other than petroleum in the rubber compound decreases.

The degree of epoxidation of epoxidized natural rubber (ENC) is preferably at least 5 mol%, more preferably at least 10 mol%. If the degree of epoxidation of the ENC is less than 5 mol%, the effect of improving the adhesion characteristics of the road surface tends to decrease. Moreover, the degree of epoxidation of epoxidized natural rubber (ENC) is preferably not more than 60 mol%, more preferably not more than 55 mol%. If the degree of epoxidation of the ENC exceeds 60 mol%, the strength of the resulting rubber of the trench layer of the tread is insufficient and the ability to connect with general-purpose rubber is reduced.

The rubber composition for the tread layer of the tread of the present invention may contain the aforementioned deproteinized natural rubber (DPNA) as a rubber component. If the rubber mixture for the under-tread layer of the tread of the present invention contains deproteinized natural rubber (DPNA), the content of deproteinized natural rubber (DPNA) in the rubber component is not particularly limited, however, it can be, for example, at least about 5% by weight. However, if the rubber composition for the undercut groove of the tread of the present invention contains natural rubber other than DPN as the rubber component, the DPN content may be less than about 5% by weight. If natural rubber other than DPNK is present as the rubber component, the rubber composition for the undercut of the tread of the present invention may not contain DPNK. On the other hand, if the rubber composition for the undercut groove of the tread of the present invention contains only DPNA as a natural rubber component, the content of DPNA in the rubber component is preferably at least 90% by weight, more preferably at least 95% by weight. If the content of DPNA is less than 90% by mass, then the proportion of non-oil resources in the rubber composition decreases and the abrasion resistance decreases. DPNA is obtained by the aforementioned method.

The rubber mixture for the undercut groove of the tread of the present invention may further comprise another modified natural rubber other than the above or a diene-based synthetic rubber. Synthetic rubber based on diene can be obtained, for example, from styrene butadiene rubber (BSK), butadiene rubber (BC), isoprenstyrene copolymer rubber, isoprene rubber (IR), isobutylene isoprene rubber (IIC), chloroprene rubber (HCR), acryl nitride (CKB), , halogenated isobutylene isoprene rubber (G-IIC) or a halide of a copolymer of isobutylene and p-methylstyrene.

If the rubber composition for the under-tread layer of the tread of the present invention contains diene-based synthetic rubber, the content of the diene-based synthetic rubber in the rubber component is preferably set to not more than 10% by weight. The rubber mixture for the under-tread tread layer of the present invention is more preferably free of diene-based synthetic rubber in order to increase the content of non-oil resources for reasons of conservation of resources and environmental protection.

Zinc oxide

The rubber composition for the undercut groove of the tread of the present invention contains zinc oxide particles having an average diameter of not more than 200 nm. Zinc oxide is introduced into the rubber composition for the under-groove tread layer of the present invention as an additional vulcanization accelerator. When the rubber composition for the under-tread layer of the tread of the present invention contains zinc oxide particles having an average particle diameter of not more than 200 nm, the rubber break caused by zinc oxide can be effectively prevented and the durability at high speeds of the resulting under-tread rubber of the tread can be improved. Further, when the rubber composition for the under-groove tread layer of the present invention contains zinc oxide particles having an average particle diameter of not more than 200 nm, rolling resistance can be improved. If the average particle diameter of zinc oxide exceeds 200 nm, the particles can serve as starting points for cracking, and durability at high speeds cannot be sufficiently improved and the rolling resistance of the resulting rubber of the groove tread layer is not reduced. To further improve durability at high speeds and reduce rolling resistance, the average particle diameter of zinc oxide is preferably not more than 150 nm, more preferably not more than 100 nm. Moreover, the average particle diameter of zinc oxide is preferably at least less than 1 nm, more preferably at least 10 nm. If the average particle diameter of the zinc oxide is less than 1 nm, the dispersibility of the zinc oxide in the rubber composition is deteriorated.

The content of zinc oxide particles having an average diameter of not more than 200 nm is at least 0.1 mass parts, preferably at least 0.5 mass parts, more preferably at least 1.0 mass parts per 100 mass parts of the rubber component . If the content of zinc oxide particles having an average diameter of not more than 200 nm is less than 0.1 mass parts, the effect of zinc oxide, which serves as an additional vulcanization accelerator, becomes difficult to achieve. Moreover, the content of zinc oxide particles having an average diameter of not more than 200 nm is not more than 10 parts by mass, preferably not more than 5 parts by mass per 100 parts by mass of the rubber component. If the content of zinc oxide particles having an average diameter of not more than 200 nm exceeds 10 mass parts, the abrasion resistance is reduced.

The rubber composition for the under-tread layer of the tread of the present invention may further comprise zinc oxide particles having an average diameter of at least 200 nm, along with zinc oxide particles having an average diameter of not more than 200 nm. However, the content of zinc oxide particles having an average diameter of at least 200 nm is preferably not more than 2.5 mass parts, more preferably not more than 1.5 mass parts per 100 mass parts of the rubber component. If the content of zinc oxide particles having an average diameter of at least 200 nm exceeds 2.5 mass parts, then the abrasion resistance deteriorates. If the rubber composition for the tread layer of the tread of the present invention further comprises zinc oxide particles having an average diameter of at least 200 nm, the ratio (mass ratio) of zinc oxide particles having an average diameter of at least 200 nm to zinc oxide particles having an average a diameter of not more than 200 nm, preferably not more than 5, more preferably not more than 3. If this ratio exceeds 5, the abrasion resistance deteriorates.

The rubber composition for the underfill tread layer of the present invention preferably further comprises silicon dioxide. Silicon dioxide acts as a reinforcing filler, and the abrasion resistance of the resulting rubber of the tread layer of the tread can be improved by introducing silicon dioxide into the rubber mixture for the tread layer of the tread.

Silicon dioxide can be obtained either wet or dry.

The BET specific surface area of the silica is preferably at least 100 m ² / g, more preferably at least 120 m ² / g. If the BET specific surface area of silicon dioxide is less than 100 m ² / g, the reinforcing effect is insufficient. Moreover, the BET specific surface area of the silica is preferably not more than 300 m ² / g, more preferably not more than 280 m ² / g. If the BET specific surface area of the silica exceeds 300 m ² / g, the adhesive capacity of the rubber deteriorates and the resulting rubber of the under-tread tread layer is prone to tearing.

If the rubber composition for the underfill tread layer of the present invention contains silicon dioxide, the silicon dioxide content is preferably at least 30 parts by mass, more preferably at least 33 parts by mass per 100 parts by mass of the rubber component. If the content of silicon dioxide is less than 30 parts by mass, a satisfactory effect of improving durability at high speeds is not achieved. Moreover, the content of silicon dioxide is preferably not more than 50 mass parts, more preferably not more than 40 mass parts per 100 mass parts of the rubber component. If the silica content exceeds 50 parts by mass, a satisfactory rolling resistance improvement effect is not achieved.

If silicon dioxide is present, the rubber composition for the underfill tread layer of the present invention preferably contains a silane coupling agent along with silicon dioxide. The type of silane coupling agent used in the rubber composition for the tread layer of the tread of the present invention, and its content are the same as the type and content of silane coupling agent used for the rubber composition for the tread of the present invention.

The rubber composition for the undercut of the tread of the present invention may contain carbon black. The BET specific area of carbon black is preferably at least 60 m ² / g, more preferably at least 70 m ² / g. If the BET specific surface area of the carbon black is less than 60 m ² / g, the reinforcing effect is insufficient. Moreover, the BET specific surface area of the carbon black is preferably not more than 200 m ² / g, more preferably not more than 180 m ² / g. If the specific surface area according to the BET of the carbon black exceeds 200 m ² / g, the reinforcing effect is reduced.

The dibutyl phthalate oil number of carbon black is preferably at least 70 ml / 100 g, more preferably 80 to 160 ml / 100 g. If the dibutyl phthalate oil number of carbon black is less than 70 ml / 100 g, the enhancing effect is reduced.

If the rubber composition for the under-tread layer of the tread of the present invention contains carbon black, the carbon black content is preferably 5 to 150 mass parts, more preferably 10 to 120 mass parts, even more preferably 15 to 100 mass parts per 100 mass parts of the rubber component. A significant improvement in rolling resistance as a result of the addition of carbon black cannot be achieved if the carbon black content is less than 5 parts by mass, while manufacturability and usability are reduced if the carbon black content exceeds 150 mass parts. However, the rubber composition for the undercut groove of the tread of the present invention preferably does not contain soot, for reasons of conservation of resources and environmental protection.

The rubber composition for the under-tread layer of the tread of the present invention may further comprise other additives, for example, such as a curing agent, vulcanization accelerator, stearic acid, metal stearate, oil, cured resin, wax, antioxidant and similar additives commonly used in the rubber industry, such as This is described for a rubber compound for a tread.

Rubber compound for a board filler

The rubber composition for a bead apex according to the present invention contains from 0.1 to 10 parts by mass of zinc oxide particles having an average particle diameter of not more than 200 nm per 100 parts by mass of the rubber component. This rubber composition for a bead apex according to the present invention gives the tire excellent rigidity, especially excellent tensile strength and crack resistance when bending the tire.

Rubber component

The rubber composition for a bead apex according to the present invention contains at least natural rubber (NR) as a rubber component. The content of natural rubber (NR) in the rubber component is preferably at least 50% by mass, more preferably at least 80% by mass, even more preferably at least 90% by mass. The natural rubber content is particularly preferably 100 mass%, that is, the rubber composition for the bead apex according to the present invention particularly preferably contains only natural rubber as the rubber component. The use of natural rubber (NK) can provide high rigidity, high durability, excellent fatigue resistance and excellent rolling resistance, and tensile strength can advantageously increase as the content of natural rubber (NK) in the rubber component increases.

Natural rubber (NR) can be obtained, for example, from materials of grades RSS # 3, TSR20 or SIR20, commonly used in the rubber industry.

The rubber composition for a bead apex according to the present invention may contain a rubber component other than natural rubber. A rubber component other than natural rubber can be obtained, for example, from epoxidized natural rubber (ENC), styrene butadiene rubber (BS), butadiene rubber (BC), isoprenic styrene copolymer rubber, isoprene rubber (IR), isobutylene isoprene rubber, I-butylene isoprene rubber (Ibutylene rubber) rubber (HC), acrylonitrile butadiene rubber (NBR), halogenated isobutylene isoprene rubber (G-IIC) or a halide of a copolymer of isobutylene and p-methylstyrene. In particular, ENCs, BSKs, BCs, or IRs are capable of providing high rigidity and durability, as well as excellent fatigue resistance, and rolling resistance is preferred, and ENCs are more preferred in terms of preserving oil resources.

If the rubber composition for the bead apex contains a rubber component other than natural rubber, then the content of the rubber component other than natural rubber in the rubber component is set such that the content of natural rubber (NR) is in the aforementioned preferred range.

If the rubber composition for a bead apex according to the present invention contains epoxidized natural rubber (ENC), then the degree of epoxidation of the epoxidized natural rubber (ENC) is preferably at least 5 mol%, more preferably at least 10 mol%. If the degree of epoxidation of the ENC is less than 5 mol%, the glass transition temperature of the ENC is so low that the effects of improving stiffness, durability, fatigue resistance, and rolling resistance become difficult to achieve. Moreover, the degree of epoxidation of epoxidized natural rubber (ENC) is preferably not more than 65 mol%, more preferably not more than 60 mol%. If the degree of epoxidation of the ENC exceeds 65 mol%, the stiffness increases excessively and the cracking resistance during bending decreases.

If the rubber composition for a bead apex according to the present invention contains natural rubber (NK) and epoxidized natural rubber (ENK), the total content of NK and ENK in the rubber component is preferably at least 50% by weight, more preferably at least 80% by weight even more preferably at least 90% of the mass. If the total content of NK and ENK in the rubber component is less than 50 wt%, sufficient rigidity and durability, as well as excellent fatigue resistance and rolling resistance, become difficult to achieve. The total content of NK and ENK in the rubber component is particularly preferably set to 100% by mass in order to increase the content of non-oil resources.

Zinc oxide

The rubber composition for a bead apex according to the present invention contains zinc oxide particles having an average diameter of not more than 200 nm. When zinc oxide is introduced into the rubber composition for a bead apex as an additional vulcanization accelerator, crack formation due to zinc oxide can be effectively prevented, and the cracking resistance of the resulting bead apex rubber can be improved when the bead apex rubber of the present invention contains zinc oxide particles having an average particle diameter of not more than 200 nm. If the average particle diameter of the zinc oxide exceeds 200 nm, the particles can serve as the starting points for cracking and the resulting bead filler rubber has a reduced flex cracking resistance. In order to further improve bending crack resistance, the average particle diameter of zinc oxide is preferably not more than 150 nm, more preferably not more than 100 nm. Moreover, the average particle diameter of the zinc oxide is preferably at least 1 nm, more preferably at least 10 nm. If the average particle diameter of the zinc oxide is less than 1 nm, the dispersibility of the zinc oxide in the rubber composition is deteriorated.

The content of zinc oxide particles is at least 0.1 mass parts, preferably at least 1 mass part, more preferably at least 3 mass parts per 100 mass parts of the rubber component. If the content of zinc oxide particles is less than 0.1 mass parts, the effect of zinc oxide, which serves as an additional vulcanization accelerator, becomes elusive. Moreover, the content of zinc oxide particles is not more than 10 parts by mass, preferably not more than 8 parts by mass per 100 parts by mass of the rubber component. If the content of particles of zinc oxide exceeds 10 mass parts, the cracking resistance during bending is reduced. The content of zinc oxide particles is most preferably from 3 to 8 parts by weight per 100 parts by weight of the rubber component, and bead apex rubber can be obtained with excellent tensile strength and bending crack resistance if the content of zinc oxide particles is in this range.

The rubber composition for the bead apex of the present invention preferably further comprises silicon dioxide. Silicon dioxide acts as a reinforcing filler, and the abrasion resistance of the resulting bead filler rubber can be improved by introducing silica into the bead apex rubber composition.

Silicon dioxide can be obtained either wet or dry.

The BET specific surface area of the silica is preferably at least 70 m ² / g, more preferably at least 80 m ² / g. If the BET specific surface area of silicon dioxide is less than 70 m ² / g, satisfactory stiffness of the resulting bead filler rubber is not achieved. Moreover, the BET specific surface area of the silica is preferably not more than 200 m ² / g, more preferably not more than 180 m ² / g. If the BET specific surface area of silicon dioxide exceeds 200 m ² / g, the workability of the rubber is impaired.

If the rubber composition for a bead apex according to the present invention contains silicon dioxide, the silica content is at least 15 parts by weight, preferably at least 30 parts by weight per 100 parts by weight of the rubber component. If the content of silicon dioxide is less than 15 parts by mass, satisfactory stiffness, in particular satisfactory tensile strength of the bead apex rubber, is not achieved. Moreover, the content of silicon dioxide is not more than 90 mass parts, preferably not more than 80 mass parts per 100 mass parts of the rubber component. If the content of silicon dioxide exceeds 90 mass parts, the workability of the rubber deteriorates and the heat dissipation of the rubber during movement increases.

If the rubber composition for the bead apex of the present invention contains silicon dioxide, it preferably contains a silane coupling agent, along with silicon dioxide. A type of silane coupling agent suitable for use in a rubber composition for a bead apex according to the present invention is similar to a type of silane coupling agent in a rubber composition for a tread according to the present invention.

The content of the silane coupling agent is preferably at least 2 parts by mass, more preferably at least 3 parts by mass per 100 parts by mass of silica. If the content of the silane coupling agent is less than 2 parts by mass, the mixing ability and extrudability of the rubber decreases, and the cracking resistance during bending also decreases. Moreover, the content of the silane coupling agent is preferably not more than 20 parts by mass, more preferably not more than 15 parts by mass per 100 parts by mass of silica. If the content of the silane coupling agent exceeds 20 parts by mass, the effect of improving the ability to mix and extrudable rubber decreases, while the cost increases uneconomically. If the content of the silane coupling agent exceeds 20 mass parts, then the cracking resistance during bending is reduced.

Although the rubber composition for the bead apex of the present invention may contain carbon black as a reinforcing filler, the carbon black content is preferably minimized, for reasons of conservation of resources and environmental protection. The rubber composition for the bead apex of the present invention is more preferably free of carbon black.

The rubber composition for the bead apex according to the present invention may further contain other additives, for example, such as a vulcanizing agent, a vulcanization accelerator, stearic acid, oil, a cured resin, wax, an antioxidant and the like, commonly used in the rubber industry, similar to those used in the rubber composition for tread.

A cured resin suitable for use in the rubber composition for the bead apex of the present invention can be prepared from a cured phenol resin, a cured cresol resin or the like. More preferably, phenol-based cured resin is used. A cured phenol-based resin can be prepared from an alkyl phenol resin, a modified phenolic oil, a modified cashew phenolic resin or the like.

The cured resin content is preferably 1 to 20 parts by mass per 100 parts by mass of the rubber component. If the cured resin is less than 1 mass part, satisfactory stiffness of the bead apex rubber may not be achieved. If the cured resin content exceeds 20 parts by weight, unvulcanized rubber has excess hardness and its workability is impaired.

Rubber compound for crimp

The rubber composition for the crimp part of the present invention contains from 0.1 to 10 parts by mass of zinc oxide particles having an average particle diameter of not more than 200 nm per 100 parts by mass of the rubber component. The rubber composition for the crimp part of the present invention provides the tire with excellent tensile strength and abrasion resistance.

Rubber component

The rubber composition for the crimp portion of the present invention contains at least natural rubber (NK) and epoxidized natural rubber.

Natural rubber (NR) can be obtained, for example, from materials of grades RSS # 3, TSR20 or SIR20, commonly used in the rubber industry.

The content of natural rubber (NK) in the rubber component is at least 30% by weight, preferably at least 40% by weight. If the content of the NK is less than 30 wt. -%, then the strength of the rubber is unsatisfactory. Moreover, the content of natural rubber (NK) in the rubber component is not more than 90% by weight, preferably not more than 80% by weight. If the content of the NC exceeds 90% by mass, the abrasion resistance does not improve sufficiently.

The content of epoxidized natural rubber (ENC) in the rubber component is at least 10% by weight, preferably at least 20% by weight. If the content of the ENC is less than 10 wt. -%, the abrasion resistance is not sufficiently improved. Moreover, the content of epoxidized natural rubber (ENC) in the rubber component is not more than 70% by weight, preferably not more than 50% by weight. If the content of the ENC exceeds 70 wt. -%, the strength of the rubber is unsatisfactory.

The degree of epoxidation of epoxidized natural rubber (ENC) is preferably at least 5 mol%, more preferably at least 10 mol%. If the degree of epoxidation of the ENC is less than 5 mol%, the glass transition temperature of the ENC is so low that high hardness and durability, as well as excellent fatigue resistance and rolling resistance become difficult to achieve. Moreover, the degree of epoxidation of epoxidized natural rubber (ENC) is preferably not more than 65 mol%, more preferably not more than 60 mol%. If the degree of epoxidation of the ENC exceeds 65 mol%, the rubber hardness becomes unsatisfactory.

The rubber composition for the crimp part of the present invention may contain a rubber component other than natural rubber and epoxidized natural rubber. A rubber component other than natural rubber and epoxidized natural rubber can be obtained, for example, from styrene butadiene rubber (BS), butadiene rubber (BK), isoprenstyrene copolymer rubber, isoprene rubber (IR), isobutylene isoprene rubber (ICR) ), acrylonitrile butadiene rubber (NBR), halogenated isobutylene isoprene rubber (G-IIC) or a halide of a copolymer of isobutylene and p-methylstyrene. Particularly preferred are BSK, BK or IR, capable of providing high hardness and durability, as well as excellent fatigue resistance and rolling resistance.

If the rubber composition for the crimp part of the present invention contains a rubber component other than natural rubber and epoxidized natural rubber, the content of the rubber component other than natural rubber and epoxidized natural rubber is preferably not more than 20% by weight. The rubber composition for the crimp portion of the present invention more preferably does not contain a rubber component other than natural rubber and epoxidized natural rubber in order to increase the content of non-oil resources for reasons of resource conservation and environmental protection.

Zinc oxide

The rubber composition for the crimp part of the present invention contains zinc oxide particles having an average diameter of not more than 200 nm. Zinc oxide is introduced into the rubber composition for the crimp part of the present invention as an additional vulcanization accelerator. When the rubber composition for the crimp part of the present invention contains zinc oxide particles having an average particle diameter of not more than 200 nm, it is possible to effectively prevent cracking due to zinc oxide, the strength and abrasion resistance of the resulting rubber of the crimp part is improved, and cracking resistance can be improved. when bending. If the average particle diameter of the zinc oxide exceeds 200 nm, the particles can serve as the starting points for cracking, the cracking resistance upon bending of the resulting rubber of the crimp portion is deteriorated, and the strength and abrasion resistance of the rubber of the crimp portion are not improved sufficiently. In order to further improve bending crack resistance, the average particle diameter of the zinc oxide is preferably not more than 150 nm, more preferably not more than 100 nm. Moreover, the average particle diameter of zinc oxide is preferably at least less than 1 nm, more preferably at least 10 nm. If the average particle diameter of the zinc oxide is less than 1 nm, the dispersibility of the zinc oxide in the rubber composition is deteriorated.

The content of zinc oxide particles is at least 0.1 mass parts, preferably at least 1 mass part, more preferably at least 3 mass parts per 100 mass parts of the rubber component. If the content of zinc oxide particles is less than 0.1 mass parts, the effect of zinc oxide, which serves as an additional vulcanization accelerator, becomes difficult to achieve. Moreover, the content of zinc oxide particles is not more than 10 parts by mass, preferably not more than 8 parts by mass per 100 parts by mass of the rubber component. If the content of zinc oxide particles exceeds 10 mass parts, the cracking resistance during bending is reduced. The content of zinc oxide particles is most preferably 3 to 8 parts by weight per 100 parts by weight of the rubber component, and if the content of zinc oxide particles is in this range, it is possible to obtain rubber for the crimp part having excellent tensile strength, abrasion resistance and cracking resistance when bending.

The rubber composition for the crimp part according to the present invention preferably further comprises silicon dioxide. Silicon dioxide acts as a reinforcing filler, and the tensile strength of the resulting rubber of the crimp portion can be improved by introducing silicon dioxide into the rubber composition for the crimp portion.

Silicon dioxide can be obtained either wet or dry.

The BET specific surface area of the silica is preferably at least 70 m ² / g, more preferably at least 80 m ² / g. If the BET specific surface area of silicon dioxide is less than 70 m ² / g, it is not possible to achieve sufficient rubber strength of the crimp portion. Moreover, the BET specific surface area of the silica is preferably not more than 200 m ² / g, more preferably not more than 180 m ² / g. If the BET specific surface area of silicon dioxide exceeds 200 m ² / g, the workability of the rubber is difficult.

If the rubber composition for the crimp portion of the present invention contains silicon dioxide, the silicon dioxide content is preferably at least 15 parts by mass, more preferably at least 30 parts by mass per 100 parts by mass of the rubber component. If the content of silicon dioxide is less than 15 parts by mass, satisfactory strength, in particular, satisfactory tensile strength of the crimp portion, is not achieved. Moreover, the content of silicon dioxide is preferably not more than 90 mass parts, more preferably not more than 80 mass parts per 100 mass parts of the rubber component. If the content of silicon dioxide exceeds 90 mass parts, the workability of the rubber is reduced, and the heat dissipation of the rubber increases during movement.

If silicon dioxide is present, the rubber composition for the crimp portion of the present invention preferably contains a silane coupling agent, along with silicon dioxide. The type of silane coupling agent suitable for use in the rubber composition for the crimp portion of the present invention is the same as the type of silane coupling agent used for the rubber composition for the tread of the present invention.

The content of the silane coupling agent is preferably at least 2 parts by mass, more preferably at least 3 parts by mass per 100 parts by mass of silica. If the content of the silane agent is less than 2 mass parts, the rubber strength is reduced. Moreover, the content of the silane coupling agent is preferably not more than 20 parts by mass, more preferably not more than 18 parts by mass per 100 parts by mass of silica. If the content of the silane coupling agent exceeds 20 mass parts, the effect of improving the ability to mix and extrude rubber is reduced, while the cost is uneconomically increased. If the content of the silane coupling agent exceeds 20 parts by mass, the strength is reduced.

Although the rubber composition for the crimp portion of the present invention may contain carbon black as a reinforcing filler, the carbon black content is preferably minimized, for reasons of conservation of resources and environmental protection. The rubber composition for the crimp portion of the present invention is more preferably free of carbon black.

The rubber composition for the crimp portion of the present invention may further comprise other additives, such as, for example, a vulcanizing agent, a vulcanization accelerator, stearic acid, metal stearate, oil, cured rubber, wax, an antioxidant and similar additives commonly used in the rubber industry, like rubber mixes for a protector.

Rubber compound for an internal lining

The rubber composition for the inner liner of the present invention contains from 0.1 to 10 mass parts of zinc oxide particles having an average particle diameter of not more than 200 nm, per 100 mass parts of the rubber component. The rubber composition for the inner liner of the present invention provides the tire with excellent characteristics of resistance to penetration of air and resistance to cracking during bending of the tire.

Rubber component

At least one rubber component selected from natural rubber (NK), epoxidized natural rubber (ENC), deproteinized natural rubber (DPNK) and other rubber based on natural basis, as well as synthetic rubber on a diene basis, are introduced into the composition of the rubber composition for internal gaskets according to the present invention. In particular, the rubber composition for the inner liner of the present invention preferably contains epoxidized natural rubber (ENC) as a rubber component.

The degree of epoxidation of epoxidized natural rubber (ENC) is preferably at least 5 mol%, more preferably at least 10 mol%. If the degree of epoxidation of the ENC is less than 5 mol%, the gas retention property is deteriorated. Moreover, the degree of epoxidation of epoxidized natural rubber (ENC) is preferably not more than 60 mol%, more preferably not more than 55 mol%. If the degree of epoxidation of the ENC exceeds 60 mol%, the heat resistance and durability deteriorate.

If the rubber composition for the inner liner of the present invention contains epoxidized natural rubber (ENC), the content of ENC in the rubber component may be, for example, at least 5% by weight. However, if the rubber composition for the inner liner of the present invention contains natural rubber other than NK as the rubber component, the ENC content may be less than about 5% by weight. On the other hand, if the rubber composition for the inner liner of the present invention contains ENC as a natural-based rubber component, the content of ENC in the rubber component is preferably at least 90% by weight, more preferably at least 95% by weight. If the content of the ENC is less than 90% by mass, the proportion of non-oil resources in the rubber composition is reduced.

The proportion of ENC in the natural-based rubber component introduced into the rubber composition is preferably higher, and may be, for example, at least 50% by weight, more preferably at least 70% by weight, even more preferably at least 90% by weight. The gas retention property can be further improved by increasing the proportion of ENC in the natural-based rubber component. The rubber composition for the inner liner of the present invention may contain only an ENC as a rubber component. Thus, the gas retention property can be further improved.

The rubber composition for the inner liner of the present invention may contain natural rubber (NK) as a rubber component. Natural rubber (NR) can be obtained, for example, from materials of grades RSS # 3, TSR20 or SIR20, commonly used in the rubber industry.

If the rubber composition for the inner liner of the present invention contains natural rubber (NK), then the NK content in the rubber component is not particularly limited, and may be, for example, at least about 5% by weight. However, if the rubber composition for the inner liner of the present invention contains natural-based rubber other than NK as a rubber component, the NK content may be less than about 5% by weight. If rubber other than NK is present as natural rubber, the rubber composition for the inner liner of the present invention may not contain NK. On the other hand, if the rubber composition for the inner liner of the present invention contains only NK as a natural-based rubber component, the NK content in the rubber component is preferably at least 90% by weight, more preferably at least 95% by weight. If the content of the NC is less than 90% by mass, the proportion of resources other than oil in the rubber composition decreases.

The rubber composition for the inner liner of the present invention may contain the aforementioned deproteinized natural rubber (DPNA) as a rubber component. If the rubber composition for the inner liner of the present invention contains deproteinized natural rubber (DPNA), the content of deproteinized natural rubber (DPNA) in the rubber component is not particularly limited, and may be, for example, at least about 5% by weight. However, if the rubber composition for the inner liner of the present invention contains natural rubber other than DPNK as the rubber component, the DPNK content may be less than about 5% by weight. If rubber other than DPNK is present as natural rubber, the rubber composition for the inner liner of the present invention may not contain DPNK. If, on the other hand, the rubber composition for the inner liner of the present invention contains only DPNK as a natural-based rubber component, the content of DPNK in the rubber component is preferably at least 90% by weight, more preferably at least 95% by weight. If the content of DPNA is less than 90% by mass, the proportion of resources other than oil in the rubber composition is reduced. DPNA is obtained by the aforementioned method.

The rubber composition for the inner liner of the present invention may contain other modified natural rubber, in addition to the above, or a diene-based synthetic rubber. Synthetic rubber based on diene can be obtained, for example, from styrene butadiene rubber (BSK), butadiene rubber (BC), isoprenstyrene copolymer rubber, isoprene rubber (IR), isobutylene isoprene rubber (IIC), chloroprene rubber (HCR), acryl nitride (CKB), , halogenated isobutylene isoprene rubber (G-IIC) or a halide of a copolymer of isobutylene and p-methylstyrene.

If the rubber composition for the inner liner of the present invention contains a diene-based synthetic rubber, then the content of the diene-based synthetic rubber in the rubber component is preferably set to not more than 10% by weight. The rubber composition for the inner liner of the present invention is more preferably free of diene-based synthetic rubber in order to increase the content of non-petroleum resources for reasons of resource conservation and environmental protection.

Zinc oxide

The rubber composition for the inner liner of the present invention contains zinc oxide particles having an average diameter of not more than 200 nm. Zinc oxide is introduced into the rubber composition for the inner linings of the present invention as an additional vulcanization accelerator. When the rubber composition for the inner liner of the present invention contains zinc oxide particles having an average diameter of not more than 200 nm, it is possible to effectively prevent the destruction of the rubber due to zinc oxide, and the penetration resistance of the resulting rubber of the inner liner can be improved. Moreover, if the rubber composition for the inner liner of the present invention contains zinc oxide particles having an average particle diameter of not more than 200 nm, bending crack resistance can be improved. If the average particle diameter of zinc oxide exceeds 200 nm, the particles can serve as the starting points for the destruction of the rubber, and the resistance to air penetration and cracking resistance when bending the resulting rubber of the inner liner cannot be significantly improved. In order to further improve the resistance to penetration of air and resistance to cracking during bending, the average particle diameter of zinc oxide is preferably not more than 150 nm, more preferably not more than 100 nm. Moreover, the average particle diameter of the zinc oxide is preferably at least 1 nm, more preferably at least 10 nm. If the average particle diameter of the zinc oxide is less than 1 nm, the dispersibility of the zinc oxide in the rubber composition is deteriorated.

The content of zinc oxide particles having an average particle diameter of not more than 200 nm is at least 0.1 mass parts, preferably at least 0.5 mass parts, more preferably at least 1.0 mass part per 100 mass parts rubber component. If the content of zinc oxide particles having an average particle diameter of not more than 200 nm is less than 0.1 mass parts, the effect of zinc oxide, which serves as an additional vulcanization accelerator, becomes difficult to achieve. Moreover, the content of zinc oxide particles having an average particle diameter of not more than 200 nm is not more than 10 parts by mass, preferably not more than 5 parts by mass per 100 parts by mass of the rubber component. If the content of zinc oxide particles having an average particle diameter of not more than 200 nm exceeds 10 mass parts, the cracking resistance during bending is reduced.

The rubber composition for the inner liner of the present invention may further comprise zinc oxide particles having an average particle diameter of at least 200 nm, along with zinc oxide particles having an average particle diameter of not more than 200 nm. However, the content of zinc oxide particles having an average particle diameter of at least 200 nm is preferably not more than 2.5 parts by mass, more preferably not more than 1.5 parts by mass per 100 parts by mass of the rubber component. If the content of zinc oxide particles having an average particle diameter of at least 200 nm exceeds 2.5 mass parts, bending cracking resistance is deteriorated. If the rubber composition for the inner liner of the present invention further comprises zinc oxide particles having an average particle diameter of at least 200 nm, a ratio (by weight) of zinc oxide particles having an average particle diameter of at least 200 nm to zinc oxide particles having the average particle diameter is not more than 200 nm, preferably not more than 5, more preferably not more than 3. If this ratio exceeds 5, the cracking resistance during bending is deteriorated.

The rubber composition for the inner liner of the present invention preferably further comprises silicon dioxide. Silicon dioxide acts as a reinforcing filler, and resistance to air penetration and cracking resistance when bending the resulting rubber of the inner liner can be further improved by introducing silicon dioxide into the rubber mixture for the inner liner.

Silicon dioxide can be obtained either wet or dry.

The BET specific surface area of the silica is preferably at least 150 m ² / g, more preferably at least 170 m ² / g. If the BET specific surface area of silicon dioxide is less than 150 m ² / g, satisfactory flexural cracking resistance cannot be achieved. Moreover, the BET specific surface area of the silica is preferably not more than 200 m ² / g, more preferably not more than 180 m ² / g. If the BET specific surface area of silicon dioxide exceeds 200 m ² / g, then the viscosity of unvulcanized rubber increases excessively.

If the rubber composition for the inner liner of the present invention contains silicon dioxide, the content of silicon dioxide is preferably at least 30 mass parts, more preferably at least 33 mass parts per 100 mass parts of the rubber component. If the content of silicon dioxide is less than 30 mass parts, it is not possible to achieve a sufficient effect of improving the resistance to penetration of air. Moreover, the content of silicon dioxide is preferably not more than 50 mass parts, more preferably not more than 40 mass parts per 100 mass parts of the rubber component. If the silica content exceeds 50 parts by mass, bending crack resistance is reduced.

If silicon dioxide is present, the rubber composition for the inner liner of the present invention preferably contains a silane coupling agent, along with silicon dioxide. The type of silane coupling agent used in the rubber composition for the inner linings of the present invention is similar to the type of silane coupling agent used for the rubber composition for the tread of the present invention.

The content of the silane coupling agent is preferably at least 1 mass part, more preferably at least 2 mass parts per 100 mass parts of silica. If the content of the silane coupling agent is less than 1 mass part, the effect of improving dispersibility, etc., is not sufficiently achieved. Moreover, the content of the silane coupling agent is preferably not more than 20 parts by mass, more preferably not more than 15 parts by mass per 100 parts by mass of silica. If the content of the silane coupling agent exceeds 20 parts by mass, they do not achieve a sufficient binding effect and the ability to enhance and abrasion resistance are reduced.

The rubber composition for the inner liner of the present invention may contain carbon black. The BET specific area of the carbon black is preferably at least 20 m ² / g, more preferably at least 25 m ² / g. If the specific surface area according to the BET of the carbon black is less than 20 m ² / g, it is difficult to achieve the effect of improving crack resistance during bending. Moreover, the BET specific surface area of the carbon black is preferably not more than 40 m ² / g, more preferably not more than 30 m ² / g. If the specific surface area according to the BET of the carbon black exceeds 40 m ² / g, the rolling resistance of the tire is reduced.

The dibutyl phthalate oil number of carbon black is preferably at least 70 to 100 ml / 100 g, more preferably 80 to 90 ml / 100 g. The viscosity of unvulcanized rubber is low and the residual rubber product deteriorates if the dibutyl phthalate oil number is less than 70 ml / 100 g, at the same time, if the dibutyl phthalate oil number exceeds 100 ml / 100 g, the viscosity of unvulcanized rubber is so high that a burn is easily formed.

The carbon black content is preferably from 0 to 10 parts by mass, more preferably from 0 to 5 parts by mass, even more preferably from 0 to 1 parts by mass per 100 parts by mass of the rubber component. If the soot content exceeds 10 parts by mass, the proportion of non-oil resources decreases. The rubber composition for the inner liner of the present invention preferably does not contain soot, for reasons of conservation of resources and environmental protection.

The rubber composition for the inner liner of the present invention may further contain other additives, for example, such as a vulcanizing agent, vulcanization accelerator, stearic acid, metal stearate, oil, cured resin, wax, antioxidant and similar additives commonly used in the rubber industry, similar to rubber mixes for a protector.

The following describes the pneumatic tire of the present invention. Figure 1 is a schematic sectional view of an example of a pneumatic tire of the present invention.

The pneumatic tire 1 shown in FIG. 1 includes a tread 2 including a tread track 2a and a tread layer 2b of a tread, a pair of sidewalls 3 extending radially inward from both ends of the tread 2, and a bead 4 located on the inner ends of the sidewalls 3, respectively. The frame 6 is located between the sides 4, while the belt belt 7, having a pulling effect to strengthen the tread 2, is located on the outside of the frame 6 and the inner side of the tread 2.

The carcass 6 is formed by at least one carcass ply obtained, for example, by arranging the carcass cords at an angle of 70 ° to 90 ° with respect to the equator of the tire CO, and this carcass ply is bent outward from the inner side along the tire axial direction around the bead cores 5 4 from the tread 2 through the sidewalls 3.

The belt 7 is formed by at least two layers of the broker, obtained, for example, by placing the cord cords of the belt at an angle of not more than 40 ° with respect to the equator of CO, and the cords of the broker are alternately laid in opposite directions with the formation of an intersection between the layers.

The bead filler rubber 8 radially extending outward from each bead core 5 is located on each bead 4, while the inner liner rubber 9 forming the inner surface of the tire abuts the inner side of the carcass 6 and the outer side of the carcass 6 is protected by crimp rubber 4G parts and rubber 3G sidewalls.

At least one of the following elements in the pneumatic tire 1 of the present invention: the treadmill 2a of the tread, the undercut of the tread 2b, the bead rubber 8, the crimp rubber 4G and the side rubber 3G are composed of the rubber composition of the present invention. At least two of these elements preferably consist of the rubber composition of the present invention and all of these elements are particularly preferably composed of the rubber composition of the present invention.

The pneumatic tire of the present invention has a high content of materials other than petroleum, obtained taking into account resource conservation and environmental protection, and exhibits excellent performance. Therefore, the pneumatic tire of the present invention can be suitably used, for example, for a passenger car as an environmental “eco-tire”.

The pneumatic tire of the present invention can be manufactured in a well known manner. For example, a tread rubber composition according to the invention containing the above components is mixed, extruded in an unvulcanized state according to the shape of a tire treadmill, and formed in a tire forming machine in a conventional manner, along with other tire elements, to form an unvulcanized tire. The pneumatic tire of the present invention can be obtained by heating this unvulcanized tire under pressure in a vulcanizer. This procedure is also applied to the rubber compounds according to the invention for the undercut groove of the tread, bead filler, crimp and inner liner.

While the present invention is further described in more detail based on examples and comparative examples, the present invention is not limited to these examples.

Examples 1-5 and comparative examples 1-5

In accordance with the composition of the mixtures shown in table 1, the components, with the exception of sulfur and vulcanization accelerators, were mixed in a Banbury mixer at a speed of 80 rpm and a temperature of 150 ° C for 3 minutes. Then, sulfur and a vulcanization accelerator were added to the obtained mixtures in the amount shown in Table 1, and the mixtures were then mixed in an open roller mill at 80 ° C for 5 minutes to obtain unvulcanized rubber mixtures. Then unvulcanized rubber compounds (rubber compounds for treads) were vulcanized at 150 ° C for 30 minutes, thus preparing test samples of vulcanized rubber according to examples 1-5 and comparative examples 1-5, respectively.

Table 1 Example Comparative example one 2 3 four 5 one 2 3 four 5 Content (mass. Parts) Epoxidized Natural Rubber one hundred one hundred one hundred one hundred one hundred one hundred one hundred one hundred one hundred BSK one hundred Silica 72 72 72 72 72 72 72 72 72 Soot 5 5 5 5 5 fifty 5 5 5 Silane Coupling Agent 5.76 5.76 5.76 5.76 5.76 5.76 5.76 5.76 5.76 Soybean oil four four four four four four four four four Antioxidant 2 2 2 2 2 5 2 2 2 2 Wax 2 2 2 2 2 3 2 2 2 2 Calcium stearate 8 8 8 8 8 2 8 8 8 Stearic acid one one one one one 2 one one one one Zinc Oxide Particles 2,4 3 1,5 0.5 0.5 Zinc oxide 1,5 1.9 2.5 3 3 3 2,4 3 Sulfur 2 2 2 2 2 2 2 2 2 2 Vulcanization accelerator 2,8 2,8 2,8 2,8 2,8 2,8 2,8 2,8 2,8 2,8 The share of resources other than oil,% of the mass. 91.5 91.5 91.5 91.5 91.5 10,2 91.3 93.8 91.5 91.5 Result
tat rating Hardness 68 68 68 68 68 70 68 68 68 68 Lambourn abrasion test one hundred 95 92 92 92 one hundred 88 90 88 85 LAT abrasion test one hundred 98 95 97 93 90 85 87 89 87 Wet grip performance test one hundred 103 99 98 95 120 98 95 97 99

The components used in Examples 1-5 and Comparative Examples 1-5 are described in more detail below.

(1) Epoxidized Natural Rubber (ENC): "ENR25" (degree of epoxidation 25 mol%), manufacturer Kumpulan Guthrie

(2) BSK: "SBR 1502" (styrene-butadiene rubber having a styrene content of 23.5% by weight) manufactured by Sumitomo Chemical Co., Ltd.

(3) Silicon dioxide: "Z115Gr" (BET: 110 m ² / g), manufacturer Rhodia

(4) Soot (highly wear-resistant furnace black): "Dia Black I" (BET: 114 m ² / g, dibutyl phthalate oil number 115 ml / 100 g), manufactured by Mitsubishi Chemical Corporation

(5) Silane coupling agent: "Si266" (bis (3-triethoxysilylpropyl) disulfide), manufactured by Degussa GmbH

(6) Soybean oil: "Daizu Shirashimeyu", manufactured by The Nissin Oil Mills, Ltd.

(7) Antioxidant: "Vulkanox4020" (N-1,3-dimethylbutyl-N'-phenyl-p-phenylenediamine), manufactured by Bayer Ltd.

(8) Wax: "OZOACE-0355", manufactured by Nippon Seiro Co., Ltd.

(9) Calcium stearate: "GF200", manufactured by Shiraishi Calcium Kaisha, Ltd.

(10) Stearic acid: "Tsubaki", manufactured by Nippon Oil and Fats Co., Ltd.

(11) Zinc Oxide Particles (Zinc Oxide Used in Examples 1-5): "Zincox Super F-2" (average particle diameter 65 nm), manufactured by Hakusuitech Ltd.

(12) Zinc oxide (zinc oxide used in examples 3-5 and comparative examples 1-5): Nishu zinc oxide (average particle diameter 500 nm), manufactured by Mitsui Mining and Smelting Co., Ltd.

(13) Sulfur: Sulfur powder treated with 5% oil, manufactured by Tsurumi Chemical Co., Ltd.

(14) Vulcanization Accelerator: "Nocceler CZ" (N-cyclohexyl-2-benzothiazyl sulfenamide), manufactured by Ouchi Shinko Chemical Industrial.

The following tests were carried out on test samples of vulcanized rubber according to examples 1-5 and comparative examples 1-5. Table 1 also presents the results.

Hardness

Hardness levels were measured using a Type A hardness tester according to JIS-K6253.

Lambourn abrasion test

The volume loss of vulcanized rubber test samples was measured using an Lambourn abrasion tester (manufacturer Iwamoto Quartz GlassLab Co., Ltd) under the following conditions: temperature 20 ° C, test time 5 minutes, peripheral test speed 80 m / min, number sand feed 15 g / min, load 3.0 kgf and a slip coefficient of 20%. Table 1 shows the relative values with respect to the volume loss in Example 1, taken as 100. The abrasion resistance improves with increasing relative value.

Abrasion test with LAT

The volume loss of vulcanized rubber test specimens was measured using a Laboratory Abrasion and Skid Tester LAT abrasion tester under the following conditions: 20 N load, 20 km / h speed and 5 ° retraction angle. Table 1 shows the relative values with respect to volume loss in Example 1, taken as 100. The abrasion resistance improves with increasing relative value.

Wet grip performance test

Wet grip performance of vulcanized rubber test specimens was measured by a portable wheel slip tester manufactured by Stanley Electric Co., Ltd according to ASTM E303-83 (wet slip test). Table 1 shows the relative values with respect to the volume loss in Example 1, taken as 100. The wet grip characteristic improves with increasing relative value.

Examples 6-10 and comparative examples 6-10

In accordance with the composition of the mixtures shown in table 2, the components, with the exception of sulfur and vulcanization accelerators, were mixed in a Banbury mixer under conditions of a speed of 80 rpm and a temperature of 150 ° C for 3 minutes. Then, sulfur and a vulcanization accelerator were added to the obtained mixtures in the amount shown in Table 2, and the mixtures were then mixed in an open roller mill at 80 ° C for 5 minutes to obtain unvulcanized rubber mixtures. Then, unvulcanized rubber compounds (rubber compounds for the under-groove tread layer) were vulcanized at 150 ° C. for 30 minutes, thereby preparing vulcanized rubber sheets according to Examples 6-10 and Comparative Examples 6-10, respectively.

table 2 Example Comparative example 6 7 8 9 10 6 7 8 9 10 Content (mass. Parts) Natural rubber (NK) one hundred one hundred one hundred one hundred one hundred one hundred one hundred one hundred one hundred BSK one hundred Silica 35 35 35 35 35 35 35 35 35 Soot 35 Soybean oil 2 2 2 2 2 2 2 2 2 2 Silane Coupling Agent 2,8 2,8 2,8 2,8 2,8 2,8 2,8 2,8 2,8 Antioxidant 1,5 1,5 1,5 1,5 1,5 1,5 1,5 1,5 1,5 1,5 Wax 1,5 1,5 1,5 1,5 1,5 1,5 1,5 1,5 1,5 1,5 Stearic acid 2 2 2 2 2 2 2 2 2 2 Zinc Oxide Particles 2,4 3 1,5 0.5 0.5 Zinc oxide 1,5 1.9 2.5 3,5 3,5 3,5 3 3,5 Sulfur 2 2 2 2 2 2 2 2 2 2 CZ vulcanization accelerator 2.6 2.6 2.6 2.6 2.6 2.6 2.6 2.6 2.6 2.6 DPG vulcanization accelerator 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 Vulcanization accelerator M 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 DM vulcanization accelerator 0.797 0.797 0.797 0.797 0.797 0.797 0.797 0.797 0.797 The share of resources other than oil,% of the mass. 93.5 93.6 93.6 93.5 93.6 6.3 93.6 93.6 93.6 93.6 Evaluation result Hardness 56 56 56 56 56 58 56 56 56 56 Rolling resistance one hundred 95 92 92 92 65 88 90 88 87 High Speed Durability BUT AT AT AT AT D FROM FROM FROM FROM

The components used in Examples 6-10 and Comparative Examples 6-10 are described in more detail below.

(1) Natural rubber (NK): "SIR25" made in Indonesia

(2) BSK: "SBR 1502" (styrene-butadiene rubber having a styrene content of 23.5% by weight) manufactured by Sumitomo Chemical Co., Ltd.

(3) Silicon dioxide: "Z115Gr" (BET: 110 m ² / g), manufacturer Rhodia

(4) Soot: "Dia Black N351 N" (BET: 69 m ² / g, dibutyl phthalate oil number 136 ml / 100 g), manufactured by Mitsubishi Chemical Corporation

(5) Soybean oil: "Daizu Shirashimeyu", manufactured by The Nissin Oil Mills, Ltd.

(6) Silane coupling agent: "Si266" (bis (3-triethoxysilylpropyl) disulfide), manufactured by Degussa GmbH

(7) Antioxidant: "Vulkanox4020" (N-1,3-dimethylbutyl-N'-phenyl-p-phenylenediamine), manufactured by Bayer Ltd.

(8) Wax: "OZOACE-0355", manufactured by Nippon Seiro Co., Ltd.

(9) Stearic acid: "Tsubaki", manufactured by Nippon Oil and Fats Co., Ltd.

(10) Zinc Oxide Particles (Zinc Oxide Used in Examples 1-5): "Zincox Super F-2" (average particle diameter 65 nm), manufactured by Hakusuitech Ltd.

(11) Zinc oxide (zinc oxide used in examples 3-5 and comparative examples 1-5): Nishu zinc oxide (average particle diameter 500 nm), manufactured by Mitsui Mining and Smelting Co., Ltd.

(12) Sulfur: Sulfur powder treated with 5% oil, manufactured by Tsurumi Chemical Co., Ltd.

(13) CZ vulcanization accelerator: "Nocceler CZ" (N-cyclohexyl-2-benzothiazyl sulfenamide), manufacturer Ouchi Shinko Chemical Industrial

(14) DPG vulcanization accelerator: "Perkacit DPG" (diphenylguanidine), manufacturer Flexsys Limited

(15) M vulcanization accelerator: "Sanceler M" (mercaptobenzothiazole), manufacturer Sanshin Chemical Industry

(16) DM vulcanization accelerator: "Sanceler DM" (dibenzothiazyl disulfide), manufactured by Sanshin Chemical Industry.

The following tests were carried out on test samples of vulcanized rubber according to examples 6-10 and comparative examples 6-10. Table 2 also presents the results.

Hardness

Hardness levels were measured using a Type A hardness tester according to JIS-K6253.

Rolling resistance tests

The loss tangent (tanδ) of the vulcanized rubber sheets of Examples 6-10 and Comparative Examples 6-10 was measured using a viscoelastic spectrometer manufactured by Ueshima Seisakusho Co., Ltd., under conditions: initial strain 10%, dynamic strain 1% , frequency 10 Hz and temperature 60 ° C. Table 2 shows the relative values with respect to the tangent of the loss angle in Example 6, taken as 100. The rolling resistance decreases and exotherm decreases with increasing relative value.

High Speed Durability

Initially, unvulcanized rubber compounds for the under-tread layer of the tread (elements of the under-tread layer of the tread) according to examples 6-10 and comparative examples 6-10 were bonded with other elements and vulcanized under pressure at a temperature of 160 ° C for 20 minutes, thereby obtaining pneumatic tires (size : 215 / 60R16). Each pneumatic tire had the structure shown in FIG. 1, described in detail below.

Pneumatic tire design

Frame: made of polyester (1670 dtex / 2)

Belt belt: made of steel cords, has a structure of 2 + 2 × 0.23 NT and an angle of 22 ° × 22 °

The ratio of the thickness of the treadmill tread and podanavko layer tread: 7/3

The durability values at high speeds of the aforementioned pneumatic tires were measured on a machine for determining durability at high speeds, manufactured by Kobe Steel, Ltd., according to ECE30. Table 2 shows the results. In this table, "A", "B", "C" and "D" indicate that the levels of durability at high speeds are at least 250 km / h, at least 230 km / h and less than 250 km / h, at least 210 km / h and less than 230 km / h, and less than 210 km / h, respectively.

Examples 11-13 and comparative example 11

In accordance with the composition of the mixtures shown in table 3, the components, with the exception of sulfur and vulcanization accelerators, were loaded into a 1.7 L Banbury mixer manufactured by Kobe Steel, Ltd., so that the degree of filling was 58%, and mixed at a speed 80 rpm for 3 minutes until a temperature of 150 ° C is reached. Then, sulfur and a vulcanization accelerator were added to the obtained mixtures in the amount shown in Table 3, and the mixtures were then mixed in an open roller mill at 80 ° С for 5 minutes to obtain unvulcanized rubber compounds (rubber compounds for bead apex). Then, uncured rubber compounds were vulcanized at 160 ° C. for 20 minutes, thereby preparing the vulcanized rubber compounds according to Examples 11-13 and Comparative Example 11, respectively.

Table 3 Example 11 Example 12 Example 13 Reference Example 11 Content (mass. Parts) Natural rubber one hundred one hundred one hundred one hundred Silica 65 65 65 65 Silane Coupling Agent 2.5 2.5 2.5 2.5 Cured resin fifteen fifteen fifteen fifteen Stearic acid 2 2 2 2 Zinc oxide 0 0 0 four Zinc Oxide Particles 0.1 5 10 0 Sulfur 3 3 3 3 NS vulcanization accelerator 2 2 2 2 Vulcanization accelerator H 1,5 1,5 1,5 1,5 Evaluation result Rubber Strength Index 96 106 109 one hundred Bending Crack Resistance (70%) 120 110 95 one hundred

The components used in examples 11-13 and comparative example 11 are described in more detail below.

(1) Natural Rubber (NK): TSR20

(2) Silicon dioxide: "Ultrasil VN3" (BET: 175 m ² / g), manufacturer Degussa GmbH

(3) Silane coupling agent: "Si266" (bis (3-triethoxysilylpropyl) disulfide), manufactured by Degussa GmbH

(4) Cured resin: phenol-based cured resin "Sumilite Resin PR12686" manufactured by Sumitomo Bakelite Co., Ltd.

(5) Stearic acid: "Kiri", manufactured by Nippon Oil and Fats Co., Ltd.

(6) Zinc oxide (zinc oxide used in comparative example 1): zinc oxide (average particle diameter 500 nm), manufactured by Mitsui Mining and Smelting Co., Ltd.

(7) Zinc Oxide Particles (Zinc Oxide Used in Examples 1-3): "Zincox Super F-2" (average particle diameter 65 nm), manufactured by Hakusuitech Ltd.

(8) Sulfur: Sulfur powder, manufactured by Tsurumi Chemical Co., Ltd.

(9) NS vulcanization accelerator: "Nocceler NS" (N-tert-butyl-2-benzothiazolylsulfenamide), manufactured by Ouchi Shinko Chemical Industrial

(10) vulcanization accelerator H: "Sanceler H" (hexamethylenetetramine), manufacturer Ogura-Sundine

The following tests for the strength of rubber and the De Mattia test for resistance to cracking under bending were carried out on test samples of vulcanized rubber compounds according to examples 11-13 and comparative example 11. Table 3 also presents the results.

Rubber Tests

Dumbbell type 3 samples were prepared from vulcanized rubber compounds, and tensile strength tests were carried out in accordance with JIS-K6251 “Vulcanized Rubber and Thermoplastic Rubber - Method for Determining Tensile Strengths” to determine tensile strength (PP) and elongation at break (UR) ), respectively. The “rubber strength index” shown in Table 3 indicates the relative values calculated according to the following equation with respect to the rubber strength index of comparative example 11, taken as 100. The tensile strength of rubber increases with increasing relative value.

Rubber strength index = {(PP * UR) for each example} / {(PP * UR) for comparative example 11} * 100

De Matthia Bending Crack Test

According to JIS-K6260 “De Matthia Tests for Crack Resistance in Bending of Vulcanized Rubber and Thermoplastic Rubber”, the number of breaks of 1 mm on each sample of vulcanized rubber was measured at room temperature of 25 ° C. Table 3 presents the relative values with respect to the number of breaks in comparative example 11, taken as 100. The indicator “70%” in table 3 indicates the elongation with respect to the initial length of each vulcanized rubber sample, expressed as a percentage.

Examples 14-16 and comparative example 12

In accordance with the composition of the mixtures shown in table 4, the components, with the exception of sulfur and vulcanization accelerators, were loaded into a 1.7 L Banbury mixer manufactured by Kobe Steel, Ltd. so that the degree of filling was 58%, and mixed at a speed of 80 rpm for 3 minutes until a temperature of 140 ° C was reached. Then, sulfur and a vulcanization accelerator were added to the obtained mixtures in the amount shown in Table 4, and the mixtures were then mixed in an open roller mill at 80 ° С for 5 minutes to obtain unvulcanized rubber compounds (rubber compounds for crimping part). Then, the uncured rubber compounds were cured at 160 ° C. for 20 minutes, thereby preparing the vulcanized rubber compounds according to Examples 14-16 and Comparative Example 12, respectively.

Table 4 Example 14 Example 15 Example 16 Reference Example 12 Content (mass. Parts) Natural rubber 70 70 70 70 Epoxidized Natural Rubber thirty thirty thirty thirty Silica 65 65 65 65 Silane Coupling Agent 2.5 2.5 2.5 2.5 Wax one one one one Antioxidant 2 2 2 2 Stearic acid 2 2 2 2 Zinc oxide 0 0 0 3 Zinc Oxide Particles 0.1 5 10 0 Sulfur 2 2 2 2 NS vulcanization accelerator one one one one Evaluation result Rubber Strength Index 95 105 108 one hundred Abrasion Resistance Index (Peak Abrasion) 96 103 97 one hundred

The components used in examples 14-16 and comparative example 12 are described in more detail below.

(1) Natural Rubber (NK): TSR20

(2) Epoxidized Natural Rubber (ENC): "ENR25" (degree of epoxidation 25 mol%), manufacturer Kumpulan Guthrie

(3) Silicon dioxide: "Ultrasil VN3" (BET: 175 m ² / g), manufacturer Degussa GmbH

(4) Silane coupling agent: "Si266" (bis (3-triethoxysilylpropyl) disulfide), manufactured by Degussa GmbH

(5) Wax: "OZOACE-0355", manufactured by Nippon Seiro Co., Ltd.

(6) Antioxidant: “6C” (N- (1,3-dimethylbutyl) -N'-phenyl-p-phenylenediamine), manufactured by Sumitomo Chemical Co., Ltd.

(7) Stearic acid: "Kiri", manufactured by Nippon Oil and Fats Co., Ltd.

(8) Zinc oxide (zinc oxide used in comparative example 1): Nishu zinc oxide (average particle diameter 500 nm), manufactured by Mitsui Mining and Smelting Co., Ltd.

(9) Zinc Oxide Particles (Zinc Oxide Used in Examples 1-3): "Zincox Super F-2" (average particle diameter 65 nm), manufactured by Hakusuitech Ltd.

(10) Sulfur: Sulfur powder, manufactured by Tsurumi Chemical Co., Ltd.

(11) NS vulcanization accelerator: "Nocceler NS" (N-tert-butyl-2-benzothiazolylsulfenamide), manufactured by Ouchi Shinko Chemical Industrial

The rubber strength tests described below and the abrasion resistance test (pick abrasion) were carried out on vulcanized mixtures according to Examples 14-16 and Comparative Example 12. Table 4 also shows the results.

Rubber Tests

Dumbbell type 3 samples were prepared from vulcanized rubber compounds, and tensile strength tests were carried out in accordance with JIS-K6251 “Vulcanized Rubber and Thermoplastic Rubber - Method for Determining Tensile Strengths” to determine tensile strength (PP) and elongation at break (UR) ) samples, respectively. The “rubber strength index” shown in Table 4 indicates the relative values calculated according to the following equation with respect to the rubber strength index of Comparative Example 12, taken as 100. The tensile strength of rubber increases with increasing relative value.

The strength index of rubber = {(PP * UR) for each example} / {(PP * UR) for comparative example 12} * 100

Abrasion resistance test (abrasion).

In accordance with JIS-K6264 “Vulcanized Rubber and Thermoplastic Rubber — Method for Determining Abrasion Resistance”, each vulcanized rubber sample was abraded under the following conditions: peripheral speed 60 rpm, load 4 kg and test time 1 min, weight change of each vulcanized sample the rubber before and after the test was measured using a picotester abrasion (picoabrasion tester), manufacturer Ueshima Seisakusho Co., Ltd. The “abrasion resistance index (abrasion)” in Table 4 shows the relative values calculated in accordance with the following equation with respect to this index for comparative example 12, taken as 100. The resistance to high-intensity abrasive wear increases with increasing relative value.

Abrasion resistance index (pic abrasion) = {mass change for each example} / {mass change for comparative example 12} * 100

Examples 17-21 and comparative examples 13-17

In accordance with the composition of the mixtures shown in table 5, the components, with the exception of sulfur and vulcanization accelerators, were mixed in a Banbury mixer under conditions of a speed of 80 rpm and a temperature of 150 ° C for 3 minutes. Then, sulfur and a vulcanization accelerator were added to the obtained mixtures in the amount shown in Table 5, and the mixtures were then mixed in an open roller mill at 80 ° С for 5 minutes to obtain unvulcanized rubber compounds (rubber compounds for internal lining). Then, uncured rubber compounds were vulcanized at 150 ° C. for 30 minutes, thereby preparing vulcanized rubber sheets according to Examples 17-21 and Comparative Examples 13-17, respectively.

Table 5 Example Comparative example 17 eighteen 19 twenty 21 13 fourteen fifteen 16 17 Content-
nie (mass. parts) Epoxidized Natural Rubber (ENC) one hundred one hundred one hundred one hundred one hundred one hundred one hundred one hundred one hundred Chlorinated Butyl Rubber one hundred Silica 35 35 35 35 35 35 35 35 35 Soot 60 Silane Coupling Agent 3.2 3.2 3.2 3.2 3.2 3.2 3.2 3.2 3.2 Antioxidant one one one one one 1,5 one one one one Calcium stearate 2 2 2 2 2 2 2 2 2 Stearic acid 1,5 1,5 1,5 1,5 1,5 2 1,5 1,5 1,5 1,5 Zinc Oxide Particles 1.8 2 one 0.8 0.5 Zinc oxide one one 1.3 3,5 3,5 3,5 3 3,5 Sulfur 1,5 1,5 1,5 1,5 1,5 2 2 2 2 2 CZ vulcanization accelerator 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 DPG vulcanization accelerator 0.25 0.25 0.25 0.25 0.25 1.25 0.25 0.25 0.25 0.25 Vulcanization accelerator M 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 DM vulcanization accelerator 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 The share of resources other than oil,% of the mass. 96.2 96.2 96.2 96.2 96.2 4.4 96.2 96.2 96.2 96.2 Result
tat rating Hardness 58 58 58 58 58 60 58 58 58 58 Rolling resistance one hundred 95 92 92 92 125 88 90 88 90 Breathability BUT AT AT AT AT BUT FROM FROM FROM FROM Bending Cracking Resistance one hundred 95 90 87 85 70 70 70 65 65

The components used in Examples 17-21 and Comparative Examples 13-17 are described in more detail below.

(1) Epoxidized Natural Rubber (ENC): "ENR25" (degree of epoxidation 25 mol%), manufacturer Kumpulan Guthrie

(2) Chlorinated butyl rubber: "Chlorobutyl HT1066", manufactured by Exxon Chemical

(3) Silicon dioxide: "Ultrasil VN3" (BET: 175 m ² / g), manufacturer Degussa GmbH

(4) Soot: "Dia Black G" (BET: 27 m ² / g, dibutyl phthalate oil number 87 ml / 100 g), manufactured by Mitsubishi Chemical Corporation

(5) Silane coupling agent: "Si266" (bis (3-triethoxysilylpropyl) disulfide), manufactured by Degussa GmbH

(6) Antioxidant: "Antioxidant FR" (purified product of a derivative of 2,2,4-trimethyl-1,2-dihydroquinoline), manufactured by Matsubara Industries, Inc.

(7) Calcium stearate: "GF200", manufactured by Shiraishi Calcium Kaisha, Ltd.

(8) Stearic acid: "Tsubaki", manufactured by Nippon Oil and Fats Co., Ltd.

(9) Zinc Oxide Particles (Zinc Oxide Used in Examples 1-5): "Zincox Super F-2" (average particle diameter 65 nm), manufactured by Hakusuitech Ltd.

(10) Zinc oxide (zinc oxide used in examples 3-5 and comparative examples 1-5): Nishu zinc oxide (average particle diameter 500 nm), manufactured by Mitsui Mining and Smelting Co., Ltd.

(11) Sulfur: Sulfur powder treated with 5% oil, manufactured by Tsurumi Chemical Co., Ltd.

(12) CZ vulcanization accelerator: "Nocceler CZ" (N-cyclohexyl-2-benzothiazylsulfenamide), manufacturer Ouchi Shinko Chemical Industrial

(13) DPG vulcanization accelerator: "Perkacit DPG" (1,3-diphenylguanidine), manufacturer Flexsys Limited

(14) M vulcanization accelerator: "Sanceler M" (2-mercapto-benzothiazole), manufacturer Sanshin Chemical Industry

(15) DM vulcanization accelerator: "Sanceler DM" (dibenzothiazyl disulfide), manufactured by Sanshin Chemical Industry.

Hardness

Hardness levels were measured using a Type A hardness tester according to JIS-K6253.

Rolling resistance tests

The loss tangent (tanδ) of vulcanized rubber sheets of Examples 17-21 and Comparative Examples 13-17 was measured using a viscoelastic spectrometer manufactured by Ueshima Seisakusho Co., Ltd., under conditions: initial strain 10%, dynamic strain 1% , frequency 10 Hz and temperature 60 ° C. Table 5 shows the relative values with respect to the loss tangent in Example 17, taken as 100. The rolling resistance decreases and exotherm decreases with increasing relative value.

Breathability test

The air permeability values for the vulcanized rubber sheets of Examples 17-21 and Comparative Examples 13-17 were measured using a gas permeability meter manufactured by Ueshima Seisakusho Co., Ltd. under normal temperature and normal pressure conditions. Table 5 also presents the results. In table 5, "A", "B" and "C" denote the permeability coefficients of at least 5 · 10 ¹¹ and less than 10 · 10 ¹¹ cm ² · cm / cm ² · c · cm RT.article, at least 10 · 10 ¹¹ and less than 15 · 10 ¹¹ cm ² · cm / cm ² · c · cm Hg and at least 15 · 10 ¹¹ and less than 20 · 10 ¹¹ cm ² · cm / cm ² · c · cm Hg, respectively.

Bending Cracking Resistance Test

According to JIS-K6260 “De Matthia Tests for Crack Resistance in Bending of Vulcanized Rubber and Thermoplastic Rubber”, the number of breaks of 1 mm on each sample of vulcanized rubber was measured at room temperature of 25 ° C. Table 5 presents the relative values with respect to the number of breaks in comparative example 17, taken as 100. The indicator "70%" in table 5 indicates the elongation relative to the original length of each vulcanized rubber sample, expressed as a percentage.

Although the present invention has been described and illustrated in detail, it should be understood that this was done only for the purpose of illustration, and the examples given do not limit the scope of protection of the present invention defined in the attached claims.

Claims (12)

1. A rubber mixture for tire tread rubber, comprising: from 0.1 to 10 mass parts of the first particles of zinc oxide having an average diameter of 1 nm to 150 nm, per 100 mass parts of the rubber component, and not more than 2.5 mass parts of the second particles of zinc oxide having an average diameter of at least 200 nm, per 100 mass parts of the rubber component. 2. The rubber composition according to claim 1, wherein said rubber component comprises epoxidized natural rubber. 3. The rubber composition according to claim 1, additionally containing from 60 to 90 mass parts of silicon dioxide per 100 mass parts of the specified rubber component. 4. A rubber mixture for rubber of the under-groove layer of a tire tread, comprising: from 0.1 to 10 mass parts of the first particles of zinc oxide having an average diameter of 1 nm to 150 nm, per 100 mass parts of the rubber component, and not more than 2.5 mass parts of the second particles of zinc oxide having an average diameter of at least 200 nm, per 100 mass parts of the rubber component. 5. The rubber mixture according to claim 4, in which the rubber component contains natural rubber. 6. The rubber composition according to claim 4, additionally containing from 30 to 50 mass parts of silicon dioxide per 100 mass parts of the specified rubber component. 7. A rubber mixture for rubber of the tire inner liner, comprising: from 0.1 to 10 mass parts of the first particles of zinc oxide having an average diameter of 1 nm to 150 nm, per 100 mass parts of the rubber component, and not more than 2.5 mass parts second particles of zinc oxide having an average diameter of at least 200 nm, per 100 mass parts of the rubber component. 8. The rubber composition of claim 7, wherein said rubber component comprises epoxidized natural rubber. 9. The rubber composition according to claim 7, additionally containing from 30 to 50 mass parts of silicon dioxide per 100 mass parts of the specified rubber component. 10. A pneumatic tire comprising tread rubber consisting of a rubber composition according to claim 1. 11. A pneumatic tire including rubber of a trench tread layer, consisting of a rubber composition according to claim 4. 12. A pneumatic tire including an inner liner rubber consisting of a rubber composition according to claim 7.

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