JP2008308554A - Rubber composition for clinch and pneumatic tire - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a rubber composition for a clinch taking due account of resource saving and environmental conservation, and compatibly attaining the durability and the process passability by increasing the rate of content of materials composed of resources other than petroleum resources; and a pneumatic tire having a clinch rubber composed of the rubber composition. <P>SOLUTION: This rubber composition for the clinch includes silica in proportion of 30-100 pts.mass to 100 pts.mass rubber component including natural rubber and/or epoxidized natural rubber, and includes a silane compound in proportion of 2-30 pts.mass to 100 pts.mass silica represented as (X)<SB>n</SB>-Si-Y<SB>(4-n)</SB>(in the formula, X expresses a methoxy group or ethoxy group, and Y expresses a phenyl group, or straight-chain or branched-chain alkyl group, (n) expresses an integer of 1-3). The pneumatic tire having the clinch rubber composed of the same rubber composition is also provided. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a rubber composition used for a tire, and more particularly to a rubber composition for clinching of a pneumatic tire. Moreover, this invention relates to a pneumatic tire provided with the clinch rubber which consists of the said rubber composition.

  In order to impart chafing performance to the clinch rubber located at the portion where the rim and the tire are in contact with each other, compounding using a large amount of carbon black has been conventionally performed. Here, the chafing performance means the abrasion resistance performance of rubber when the tire and the rim are rubbed. Carbon black is a material derived from petroleum resources.

  However, in recent years, environmental issues have become more important and regulations on carbon dioxide emissions have been strengthened. In addition, since the existing amount of petroleum is limited, the use of raw materials derived from petroleum resources is limited. This environment-oriented orientation is no exception in the field of tires, and the development of a rubber composition for clinch that replaces some or all of the raw materials derived from petroleum resources with raw materials derived from non-oil resources. It has been demanded.

  For example, Patent Document 1 discloses an eco-tire using silica or the like as a non-petroleum resource as an alternative raw material for carbon black. However, in the rubber composition for clinch, when a white filler such as silica is used instead of carbon black, there is a problem in process passability such as an increase in viscosity.

  By the way, Patent Documents 2 to 5 disclose techniques for blending a silylating agent into a rubber composition for a tire tread or a rubber composition for a sidewall for the purpose of improving grip properties or water repellency. ing. However, the compatibility between durability and process passability is not considered, and there is room for improvement.

Thus, in a rubber composition in which a raw material derived from petroleum resources is replaced with a raw material derived from non-petroleum resources, a rubber composition suitable for clinch rubber having both durability and processability is obtained. The current situation is not.
JP 2003-63206 A Japanese Unexamined Patent Publication No. 7-118454 JP 7-292158 A JP-A-9-87427 Japanese Patent Laid-Open No. 10-60175

  The present invention has been made in order to solve the above-mentioned problems, and the purpose of the present invention is to sufficiently consider resource saving and environmental protection by increasing the content ratio of materials made of resources other than petroleum. At the same time, it is to provide a rubber composition for clinch in which both durability and processability are achieved, and a pneumatic tire including a clinch rubber made of the rubber composition.

This invention contains 30-100 mass parts of silica with respect to 100 mass parts of rubber components containing a natural rubber and / or an epoxidized natural rubber, and with respect to 100 mass parts of silica, following General formula (1) :
(X) _n -Si-Y _(4-n) (1)
(In the above general formula (1), X represents a methoxy group or an ethoxy group, Y represents a phenyl group or a linear or branched alkyl group, and n represents an integer of 1 to 3).
It is a rubber composition for clinch containing 2-30 mass parts of silane compounds represented by these. Here, X in the general formula (1) is preferably an ethoxy group.

  Moreover, it is preferable that the rubber composition for clinch of this invention further contains 5-15 mass parts silane coupling agents with respect to 100 mass parts of said silicas.

  Furthermore, this invention provides a pneumatic tire provided with the clinch rubber which consists of the said rubber composition.

  According to the present invention, by increasing the content ratio of materials made from non-petroleum resources, consideration for resource saving and environmental protection is sufficient, and durability, in particular, wear resistance and processability are improved. A rubber composition for clinch that achieves both compatibility and a pneumatic tire including a clinch rubber made of the rubber composition are provided. Thereby, traveling safety is improved.

The rubber composition for clinch of the present invention contains 30 to 100 parts by mass of silica with respect to 100 parts by mass of a rubber component containing natural rubber and / or epoxidized natural rubber, and with respect to 100 parts by mass of silica, The following general formula (1):
(X) _n -Si-Y _(4-n) (1)
(In the above general formula (1), X represents a methoxy group or an ethoxy group, Y represents a phenyl group or a linear or branched alkyl group, and n represents an integer of 1 to 3).
2-30 mass parts of silane compounds represented by this are characterized. Hereinafter, each component contained in the rubber composition for clinch of the present invention will be described in detail.

<Rubber component>
The rubber composition for clinch of the present invention contains a natural rubber component such as natural rubber (NR) and epoxidized natural rubber as a rubber component.

  As the natural rubber, those conventionally used in the rubber industry can be used, and examples thereof include natural rubber of grades such as RSS and TSR.

  The content of natural rubber (NR) in the rubber component is not particularly limited, and for example, only natural rubber may be contained as the rubber component.

  The rubber composition for clinch of the present invention may contain epoxidized natural rubber as a rubber component. As the epoxidized natural rubber (ENR), a commercially available product may be used, or an epoxidized natural rubber (NR) may be used. The method for epoxidizing NR is not particularly limited, and examples thereof include a chlorohydrin method, a direct oxidation method, a hydrogen peroxide method, an alkyl hydroperoxide method, and a peracid method. Examples of the peracid method include a method of reacting an organic peracid such as peracetic acid or formic acid with natural rubber.

  The epoxidation rate of the epoxidized natural rubber (ENR) is not particularly limited. For example, ENR (ENR25) having an epoxidation rate of 25 mol%, ENR (ENR50) having an epoxidation rate of 50 mol%, or the like may be used. The epoxidation rate of the epoxidized natural rubber (ENR) means (number of epoxidized double bonds) / (number of double bonds before epoxidation).

  In the present invention, only one ENR may be used, or two or more ENRs having different epoxidation rates may be used.

  When epoxidized natural rubber (ENR) is contained, the content of epoxidized natural rubber (ENR) in the rubber component is not particularly limited.

  The rubber composition for clinch of the present invention may contain a natural rubber component other than natural rubber and epoxidized natural rubber as a rubber component. Examples of such include deproteinized natural rubber (DPNR). Natural rubber (NR) usually contains about 5 to 10% by mass of non-rubber components such as proteins and lipids. These non-rubber components, particularly proteins, are said to cause entanglement of molecular chains and cause gelation. In order to avoid such a problem, it is very advantageous to blend a deproteinized natural rubber (DPNR) from which the non-rubber component in the natural rubber is removed into the rubber composition.

  Here, it is preferable that the weight average molecular weight (gel permeation chromatography (GPC), polystyrene conversion) of deproteinized natural rubber (DPNR) is 1.4 million or more. When the weight average molecular weight is less than 1,400,000, the strength of raw rubber is lowered. The nitrogen content of the deproteinized natural rubber (DPNR) is preferably 0.1% by mass or less, more preferably 0.08% by mass or less, and further preferably 0.05% by mass or less. preferable. When the nitrogen content exceeds 0.1% by mass, it becomes a factor causing gelation.

Deproteinized natural rubber (DPNR) can be obtained by deproteinizing natural rubber (NR). Examples of the deproteinization treatment of natural rubber (NR) include the following methods.
(1) A method of degrading protein by adding a proteolytic enzyme or bacteria to natural rubber latex,
(2) A method in which alkali is added to natural rubber latex and heated to decompose proteins,
(3) A method for liberating proteins adsorbed on natural rubber latex by a surfactant.

  The natural rubber latex used for the deproteinization treatment is not particularly limited, and field latex, ammonia-treated latex and the like can be used.

  As the proteolytic enzyme used in the above method (1), conventionally known proteolytic enzymes can be used, and are not particularly limited. For example, protease is preferably used. Protease may be derived from bacteria, filamentous fungi, or yeast. Among these, bacteria-derived proteases are preferred. In addition, enzymes such as lipase, esterase, amylase, laccase and cellulase may be used in combination.

  When alkaline protease is used as the proteolytic enzyme, the activity is preferably in the range of 0.1 to 50 APU / g, preferably 1 to 25 APU / g. Here, the activity of the proteolytic enzyme is determined by the Anson-hemoglobin method [Anson. M.M. L. , J .; Gen. Physiol. , 22, 79 (1938)]. That is, after reacting at a temperature of 25 ° C. and a pH of 10.5 for 10 minutes in a solution adjusted so that the final concentration of urea-modified hemoglobin used as a substrate is 14.7 mg / ml, trichloroacetic acid is terminated in the reaction solution. Add to a concentration of 31.25 mg / ml. Subsequently, the soluble content of trichloroacetic acid is colored with a phenol reagent, and the activity per 10 minutes of reaction is obtained by a calibration curve with the coloration degree of 1 mol of tyrosine as 1 APU, and this is converted per 1 minute. Measure. In addition, 1 APU indicates the amount of protease that gives a soluble amount of trichloroacetic acid having the same coloration degree as 1 mol of tyrosine is colored by a phenol reagent in one minute.

  The addition amount of the proteolytic enzyme is appropriately set depending on the enzyme activity, but is usually 0.0001 to 20 parts by mass, preferably 0.001 to 10 parts by mass with respect to 100 parts by mass of the solid content of natural rubber latex. It is. If the amount of the proteolytic enzyme added is less than 0.0001 parts by mass, the protein in the natural rubber latex may not be sufficiently decomposed. If the amount exceeds 20 parts by mass, the activity of the enzyme is reduced and the cost is reduced. Becomes higher.

  The treatment time with the proteolytic enzyme is not particularly limited and can be appropriately set according to the enzyme activity. Usually, it is preferable to perform the treatment for several minutes to one week. During the proteolytic treatment, the natural rubber latex may be agitated or allowed to stand. Moreover, you may adjust temperature as needed, and it is 5-90 degreeC as a suitable temperature, Preferably it is 20-60 degreeC. If the treatment temperature exceeds 90 ° C., the enzyme is rapidly deactivated, and if it is less than 5 ° C., the enzyme reaction is difficult to proceed.

  As the surfactant used in the above method (3), for example, one or more of an anionic surfactant, a nonionic surfactant, and a zwitterionic surfactant can be used. Examples of the anionic surfactant include carboxylic acid type, sulfonic acid type, sulfate ester type, and phosphate ester type. As the nonionic surfactant, for example, polyoxyalkylene ether, polyoxyalkylene ester, polyhydric alcohol fatty acid ester, sugar fatty acid ester, alkyl polyglycoside, and the like are preferably used. Examples of zwitterionic surfactants include amino acid type, betaine type, and amine oxide type.

  In the method (3), the natural rubber latex is washed with a surfactant to liberate proteins adsorbed on the natural rubber latex. As a method for cleaning the natural rubber latex particles with the surfactant, either a method for cleaning the natural rubber latex not treated with enzyme or a method for cleaning the natural rubber latex that has been subjected to the enzyme treatment may be used. Specific cleaning methods include, for example, a method in which a surfactant is added to natural rubber latex that has not been treated with enzyme or natural rubber latex that has been treated with enzyme, and a method in which natural rubber latex particles are aggregated and separated. Can be mentioned. When the natural rubber latex is washed by centrifugation, the centrifugation can be performed once to several times. Usually, a deproteinized natural rubber latex from which protein is highly removed can be obtained by one centrifugation. Moreover, you may perform a centrifugation process, after diluting with water so that the rubber component of a natural rubber latex may be 5-40 mass%, Preferably it is 10-30 mass%.

  The addition amount of the surfactant is 0.001 to 20 parts by mass, preferably 0.001 to 15 parts by mass with respect to 100 parts by mass of the solid content of the natural rubber latex.

  In the above methods (1) and (3), when using a proteolytic enzyme or a surfactant, other additives such as a pH adjusting agent and a dispersing agent may be added.

  Examples of pH adjusters include phosphates such as potassium dihydrogen phosphate, potassium hydrogen phosphate, sodium dihydrogen phosphate, and sodium hydrogen phosphate; acetates such as potassium acetate and sodium acetate; sulfuric acid, acetic acid, hydrochloric acid, Examples thereof include acids such as nitric acid, citric acid and succinic acid or salts thereof; ammonia, potassium hydroxide, sodium hydroxide, sodium carbonate, sodium hydrogen carbonate and the like. The addition amount of the pH adjuster is usually 0.01 to 0.5 parts by mass with respect to 100 parts by mass of the rubber solid content of the natural rubber latex.

  Examples of the dispersant include styrene sulfonic acid copolymer, naphthalene sulfonic acid formalin condensate, lignin sulfonic acid, polycyclic aromatic sulfonic acid copolymer, acrylic acid, maleic anhydride homopolymer and copolymer, isobutylene- Examples thereof include a copolymer of acrylic acid and isobutylene-maleic anhydride.

  The deproteinized natural rubber latex obtained as described above may be coagulated after removing the non-rubber component by centrifugation or the like, or may be coagulated without removing the non-rubber component. The coagulation method is not particularly limited and can be performed by a known method. Usually, a latex rubber particle is destabilized and solidified by adding a coagulant such as formic acid or sulfuric acid or a salt such as sodium chloride. A method of destabilizing and solidifying is used.

  In addition, it is preferable that the gel content rate of deproteinized natural rubber is 10 mass% or less. When the gel content exceeds 10% by mass, the viscosity of the unvulcanized rubber increases and the processability tends to decrease. The gel content is measured as a toluene insoluble matter.

  When the deproteinized natural rubber (DPNR) is contained, the content of the deproteinized natural rubber (DPNR) in the rubber component is not particularly limited.

  The rubber composition for clinch of the present invention may contain a diene synthetic rubber in addition to the above-mentioned natural rubber component. Examples of the diene-based synthetic rubber include styrene butadiene rubber (SBR), polybutadiene rubber (BR), styrene isoprene copolymer rubber, isoprene rubber (IR), butyl rubber (IIR), chloroprene rubber (CR), acrylonitrile butadiene rubber ( NBR), halogenated butyl rubber (X-IIR), and halides of copolymers of isobutylene and p-methylstyrene. Among these, polybutadiene rubber (BR), styrene butadiene rubber (SBR), and combinations thereof can be suitably used.

  When the rubber composition for clinch of the present invention contains a diene synthetic rubber, the content of the diene synthetic rubber is preferably 250 parts by mass or less with respect to 100 parts by mass of the natural rubber component. However, in consideration of resource saving and environmental protection, it is more preferable not to include a diene synthetic rubber from the viewpoint of increasing the content of non-petroleum resources.

<Silica>
The rubber composition for clinch of the present invention contains silica. Silica functions as a reinforcing filler, and the incorporation of silica can improve the low heat buildup and abrasion resistance of the resulting clinch rubber.

  Silica may be prepared by a wet method or may be prepared by a dry method.

The BET specific surface area of silica is preferably 50 m ² / g or more, and more preferably 100 m ² / g or more. When the BET specific surface area of silica is less than 50 m ² / g, the abrasion resistance tends to be inferior. Further, BET specific surface area of silica is preferably 300 meters ² / g or less, more preferably 250m ² / g. When the BET specific surface area of silica exceeds 300 m ² / g, the dispersibility tends to be inferior or the exothermicity tends to increase. Specifically, Ultrazil VN2 (BET specific surface area: 125 m ² / g) or Ultrazil VN3 (BET specific surface area: 210 m ² / g) manufactured by Degussa can be suitably used.

  The content of silica is 30 parts by mass or more with respect to 100 parts by mass of the rubber component. When the silica content is less than 30 parts by mass, sufficient abrasion resistance tends to be not ensured. As for content of a silica, 40 mass parts or more are more preferable with respect to 100 mass parts of rubber components. Further, the content of silica is 100 parts by mass or less and more preferably 80 parts by mass or less with respect to 100 parts by mass of the rubber component. When the content of silica exceeds 100 parts by mass, the rubber viscosity becomes high and the process passability tends to be inferior or the exothermicity tends to increase.

<Silane compound>
The rubber composition for clinch of the present invention contains a silane compound. By adding the silane compound, it is possible to obtain a rubber composition in which the viscosity is significantly reduced and process passability is improved while ensuring durability, particularly wear resistance.

Here, the silane compound in the present invention is the following general formula (1):
(X) _n -Si-Y _(4-n) (1)
(In the above general formula (1), X represents a methoxy group or an ethoxy group, Y represents a phenyl group or a linear or branched alkyl group, and n represents an integer of 1 to 3).
It is a silane compound represented by these.

  X in the general formula (1) is more preferably an ethoxy group because it is more compatible with the rubber component. For the same reason, Y in the general formula (1) is more preferably a phenyl group. Moreover, n in the said General formula (1) is an integer of 1-3. When n is 0, X does not exist, and the reactivity of the silane compound tends to increase too much. When n is 4, Y does not exist and the reactivity of the silane compound tends to decrease.

  Specific examples of the silane compound represented by the general formula (1) include, for example, methyltrimethoxysilane, dimethyldimethoxysilane, phenyltrimethoxysilane, diphenyldimethoxysilane, methyltriethoxysilane, dimethyldiethoxysilane, and phenyl. Examples include triethoxysilane, diphenyldiethoxysilane, hexyltrimethoxysilane, hexyltriethoxysilane, decyltrimethoxysilane, and trifluoropropyltrimethoxysilane. These silane compounds may be used alone or in combination of two or more. Phenyltriethoxysilane is preferred because it is compatible with rubber and can reduce costs.

  Content of a silane compound is 2 mass parts or more with respect to 100 mass parts of silica, Preferably it is 5 mass parts or more. When the content of the silane compound is less than 2 parts by mass, the viscosity is high and the process passability tends to be inferior. Moreover, content of a silane compound is 30 mass parts or less with respect to 100 mass parts of silica, Preferably it is 20 mass parts or less. When the content of the silane compound exceeds 30 parts by mass, the wear resistance tends to be inferior.

<Silane coupling agent>
It is preferable to mix | blend a silane coupling agent with the rubber composition for clinch of this invention with a silica. As the silane coupling agent, a conventionally known silane coupling agent can be used. 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-triethoxy Silylpropyl) trisulfide, bis (2-triethoxysilylethyl) trisulfide, bis (4-triethoxysilylbutyl) trisulfide, bis (3-trimethoxysilylpropyl) trisulfide, bis (2-trimethoxysilylethyl) ) Resulfide, bis (4-trimethoxysilylbutyl) trisulfide, bis (3-triethoxysilylpropyl) disulfide, bis (2-triethoxysilylethyl) disulfide, bis (4-triethoxysilylbutyl) disulfide, bis (3 -Trimethoxysilylpropyl) disulfide, bis (2-trimethoxysilylethyl) disulfide, bis (4-trimethoxysilylbutyl) disulfide, 3-trimethoxysilylpropyl-N, N-dimethylthiocarbamoyltetrasulfide, 3-tri Ethoxysilylpropyl-N, N-dimethylthiocarbamoyl tetrasulfide, 2-triethoxysilylethyl-N, N-dimethylthiocarbamoyl tetrasulfide, 2-trimethoxysilylethyl-N, N-dimethylthio Sulfide systems such as rubamoyl tetrasulfide, 3-trimethoxysilylpropylbenzothiazolyl tetrasulfide, 3-triethoxysilylpropylbenzothiazole tetrasulfide, 3-trimethoxysilylpropyl methacrylate monosulfide; 3-mercaptopropyltrimethoxysilane Mercapto series such as 3-mercaptopropyltriethoxysilane, 2-mercaptoethyltrimethoxysilane, 2-mercaptoethyltriethoxysilane; Vinyl series such as vinyltriethoxysilane and vinyltrimethoxysilane; 3-aminopropyltriethoxysilane 3-aminopropyltrimethoxysilane, 3- (2-aminoethyl) aminopropyltriethoxysilane, 3- (2-aminoethyl) aminopropyltrimethoxy Amino systems such as silane; glycidoxy systems such as γ-glycidoxypropyltriethoxysilane, γ-glycidoxypropyltrimethoxysilane, γ-glycidoxypropylmethyldiethoxysilane, γ-glycidoxypropylmethyldimethoxysilane Nitro compounds such as 3-nitropropyltrimethoxysilane and 3-nitropropyltriethoxysilane; 3-chloropropyltrimethoxysilane, 3-chloropropyltriethoxysilane, 2-chloroethyltrimethoxysilane, 2-chloroethyltri Chloro-based compounds such as ethoxysilane; These silane coupling agents may be used alone or in combination of two or more.

  Of these, Si69 (bis (3-triethoxysilylpropyl) tetrasulfide), Si266 (bis (3-triethoxysilylpropyl) disulfide) manufactured by Degussa are preferably used because of their good processability. It is done.

  4 mass parts or more are preferable with respect to 100 mass parts of silica, and, as for content of a silane coupling agent, 5 mass parts or more are more preferable. If the content is less than 4 parts by mass, the strength of the rubber tends to decrease. Moreover, 15 mass parts or less are preferable with respect to 100 mass parts of silica, and, as for content of a silane coupling agent, 12 mass parts or less are more preferable. When it exceeds 15 parts by mass, the wear resistance tends to be inferior.

<Carbon black>
The rubber composition for clinch of the present invention may contain carbon black from the viewpoint of ensuring rubber reinforcement and wear resistance. However, from the viewpoint of resource saving and environmental protection, it is preferable not to contain carbon black.

<Other ingredients>
In addition to the above-described components, the rubber composition for clinch of the present invention contains other additives such as a vulcanizing agent, a vulcanization accelerator, stearic acid, oil, wax, anti-aging agent, zinc white and the like. May be.

  As the vulcanizing agent, an organic peroxide or a sulfur-based vulcanizing agent can be used. Examples of the organic peroxide include benzoyl peroxide, dicumyl peroxide, and di-t-butyl peroxide. , T-butyl cumyl peroxide, methyl ethyl ketone peroxide, cumene hydroperoxide, 2,5-dimethyl-2,5-di (t-butylperoxy) hexane, 2,5-dimethyl-2,5-di (benzoyl) Peroxy) hexane, 2,5-dimethyl-2,5-di (t-butylperoxy) hexyne-3 or 1,3-bis (t-butylperoxypropyl) benzene, di-t-butylperoxy- Diisopropylbenzene, t-butylperoxybenzene, 2,4-dichlorobenzoyl peroxide, 1,1-di t- butyl peroxy-3,3,5-trimethyl siloxane, and the like can be used n- butyl-4,4-di -t- butyl peroxy valerate. Of these, dicumyl peroxide, t-butylperoxybenzene and di-t-butylperoxy-diisopropylbenzene are preferred. Moreover, as a sulfur type vulcanizing agent, sulfur, morpholine disulfide, etc. can be used, for example. Of these, sulfur is preferred. These vulcanizing agents may be used alone or in combination of two or more.

  Vulcanization accelerators include sulfenamide, thiazole, thiuram, thiourea, guanidine, dithiocarbamic acid, aldehyde-amine or aldehyde-ammonia, imidazoline, or xanthate vulcanization accelerators. Those containing at least one of them can be used. Examples of the sulfenamide system include CBS (N-cyclohexyl-2-benzothiazylsulfenamide), TBBS (N-tert-butyl-2-benzothiazylsulfenamide), N, N-dicyclohexyl-2- Sulfenamide compounds such as benzothiazylsulfenamide, N-oxydiethylene-2-benzothiazylsulfenamide, and N, N-diisopropyl-2-benzothiazolesulfenamide can be used. Examples of the thiazole group include MBT (2-mercaptobenzothiazole), MBTS (dibenzothiazyl disulfide), sodium salt of 2-mercaptobenzothiazole, zinc salt, copper salt, cyclohexylamine salt, 2- (2,4-dinitro). Thiazole compounds such as phenyl) mercaptobenzothiazole and 2- (2,6-diethyl-4-morpholinothio) benzothiazole can be used. Examples of thiurams include TMTD (tetramethyl thiuram disulfide), tetraethyl thiuram disulfide, tetramethyl thiuram monosulfide, dipentamethylene thiuram disulfide, dipentamethylene thiuram monosulfide, dipentamethylene thiuram tetrasulfide, dipentamethylene thiuram hexasulfide. Further, thiuram compounds such as tetrabutylthiuram disulfide and pentamethylenethiuram tetrasulfide can be used. As the thiourea series, for example, thiourea compounds such as thiacarbamide, diethylthiourea, dibutylthiourea, trimethylthiourea, diortolylthiourea and the like can be used. Examples of guanidine-based compounds include guanidine-based compounds such as diphenylguanidine, diortolylguanidine, triphenylguanidine, orthotolylbiguanide, and diphenylguanidine phthalate. Examples of dithiocarbamate include zinc ethylphenyldithiocarbamate, zinc butylphenyldithiocarbamate, sodium dimethyldithiocarbamate, zinc dimethyldithiocarbamate, zinc diethyldithiocarbamate, zinc dibutyldithiocarbamate, zinc diamyldithiocarbamate, zinc dipropyldithiocarbamate , Complex salt of zinc pentamethylenedithiocarbamate and piperidine, zinc hexadecyl (or octadecyl) isopropyldithiocarbamate, zinc dibenzyldithiocarbamate, sodium diethyldithiocarbamate, piperidine pentamethylenedithiocarbamate, selenium dimethyldithiocarbamate, tellurium diethyldithiocarbamate, diamyl Di, such as cadmium dithiocarbamate And the like can be used Okarubamin acid compound. As the aldehyde-amine system or aldehyde-ammonia system, for example, an aldehyde-amine system or aldehyde-ammonia system compound such as acetaldehyde-aniline reaction product, butyraldehyde-aniline condensate, hexamethylenetetramine, acetaldehyde-ammonia reaction product, etc. is used. can do. As the imidazoline-based compound, for example, an imidazoline-based compound such as 2-mercaptoimidazoline can be used. As the xanthate type, for example, a xanthate type compound such as zinc dibutylxanthate can be used. These vulcanization accelerators may be used alone or in combination of two or more.

  As the anti-aging agent, amine-based, phenol-based, imidazole-based, carbamic acid metal salts, and the like can be appropriately selected and used.

  As the oil, for example, process oil, vegetable oil and fat, and a mixture thereof can be used. Examples of the process oil include paraffinic process oil, naphthenic process oil, and aromatic process oil. Vegetable oils include castor oil, cottonseed oil, rapeseed oil, rapeseed oil, soybean oil, palm oil, coconut oil, peanut oil, rosin, pine oil, pineapple oil, tall oil, corn oil, rice bran oil, beet flower oil, Sesame oil, olive oil, sunflower oil, palm kernel oil, coconut oil, jojoba oil, macadamia nut oil, safflower oil, tung oil, and the like.

  The pneumatic tire of the present invention is a pneumatic tire provided with clinch rubber made of the rubber composition for clinch of the present invention. Hereinafter, the pneumatic tire of the present invention will be described with reference to FIG. FIG. 1 illustrates a pneumatic tire according to the present invention. The pneumatic tire 1 includes a tread portion 2 having a cap tread portion and a base tread portion, a pair of sidewall portions 3 extending inward in the tire radial direction from both ends of the tread portion 2, and each of the sidewall portions 3. It is common to have a structure comprising a bead portion 4 located at the end. A carcass 6 is bridged between the bead portions 4, and a belt layer 7 that reinforces the tread portion 2 with a tagging effect is disposed outside the carcass 6 and inside the tread portion 2. .

  The carcass 6 is formed of one or more carcass plies 6a in which the carcass cord is arranged at an angle of, for example, 70 to 90 ° with respect to the tire equator CO. The carcass ply 6a extends from the tread portion 2 to the sidewall portion. 3, the periphery of the bead core 5 of the bead portion 4 is folded back and locked from the inner side to the outer side in the tire axial direction.

  The belt layer 7 is composed of two or more belt plies 7a in which the belt cord is arranged at an angle of, for example, 40 ° or less with respect to the tire equator CO. It is location.

  Further, a bead apex rubber 8 extending radially outward from the bead core 5 is disposed in the bead portion 4, and an inner liner rubber 9 forming a tire lumen surface is adjacent to the inside of the carcass 6. The outside of the carcass 6 is protected by clinch rubber 4G and sidewall rubber 3G. The rubber composition for clinch of the present invention is used for the clinch rubber 4G.

  The pneumatic tire of the present invention is manufactured by a conventionally known method using the rubber composition for clinch of the present invention. That is, the rubber composition for clinches having the above-described structure is kneaded and extruded in accordance with the shape of the clinched portion of the tire at an unvulcanized stage, and is used in a normal method on a tire molding machine together with other members of the tire. An unvulcanized tire is formed by molding with. The pneumatic tire of the present invention can be obtained by heating and pressurizing the unvulcanized tire in a vulcanizer.

  Such a pneumatic tire of the present invention has a higher content ratio of materials made of non-petroleum resources to clinch rubber, has sufficient consideration for resource saving and environmental protection, and ensures durability, particularly wear resistance. However, since the rubber composition having greatly reduced viscosity and improved process passability is used, it can be suitably used as, for example, a passenger car or the like as an “eco tire” that is friendly to the global environment.

  EXAMPLES Hereinafter, although an Example and a comparative example are given and this invention is demonstrated in detail, this invention is not limited to these.

<Examples 1-5 and Comparative Examples 1-4>
In accordance with the formulation shown in Table 1, the components other than sulfur and the vulcanization accelerator were kneaded for 3 minutes at a rotational speed of 80 rpm and 150 ° C. using a Kobe Steel 1.7 L Banbury mixer. Next, sulfur and a vulcanization accelerator were added to the obtained kneaded material in the amounts shown in Table 1, and then kneaded at 80 ° C. for 5 minutes using an open roll to obtain an unvulcanized rubber composition. . Next, the unvulcanized rubber composition was vulcanized at 150 ° C. for 30 minutes to prepare vulcanized rubber sheets of Examples 1 to 5 and Comparative Examples 1 to 4.

Details of the various blending components used in the above Examples and Comparative Examples are as follows.
(1) Natural rubber (NR): SIR20
(2) Silane compound: “KBE-103” (phenyltriethoxysilane) manufactured by Shin-Etsu Chemical Co., Ltd.
(3) Silica: “Ultra Gil VN3” manufactured by Degussa (BET specific surface area: 210 m ² / g)
(4) Anti-aging agent: “Antigen 6C” (N- (1,3-dimethyl-butyl) -N′-phenyl-p-phenylenediamine) manufactured by Sumitomo Chemical
(5) Stearic acid: Stearic acid “椿” manufactured by NOF Corporation
(6) Zinc flower: “Zinc flower No. 1” manufactured by Mitsui Mining & Smelting Co., Ltd.
(7) Sulfur: Powder sulfur manufactured by Tsurumi Chemical Industry Co., Ltd. (8) Vulcanization accelerator DPG: “Noxeller D” (diphenylguanidine) manufactured by Ouchi Shinsei Chemical Industry Co., Ltd.
(9) Vulcanization accelerator TBBS: “Noxeller NS” (TBBS) manufactured by Ouchi Shinsei Chemical Industry Co., Ltd.
The test shown below was implemented about the vulcanized rubber sheet of Examples 1-5 and Comparative Examples 1-4. The results are shown in Table 1.

<Mooney viscosity test>
The Mooney viscosity test was performed under the condition of 130 ° C. using a Mooney tester as an index of process passability. The numerical values shown in Table 1 are relative values when the Mooney viscosity of Example 1 is taken as 100. It shows that a viscosity is so low that the said numerical value is small and process permeability is high. When the numerical value is 100 or less, the process passability is good (A in Table 1), and when it exceeds 110, the process passability is not good (B in Table 1).

<Pico abrasion test>
In accordance with JIS-K6264 “vulcanized rubber and thermoplastic rubber rubber-how to determine wear resistance”, surface rotation speed 60 rpm, load load 4 kg, test time 1 minute with a pico abrasion tester manufactured by Ueshima Seisakusho Co., Ltd. The weight change before and after the test of each vulcanized rubber specimen was measured. The numerical values shown in Table 1 are relative values when the weight change of Example 1 is 100. A larger value indicates higher wear resistance and higher chafing performance. When the numerical value is 70 or more, the chafing performance is in an acceptable range (A in Table 1), and when it is less than 70, the chafing performance is insufficient (B in Table 1).

  It should be understood that the embodiments and examples disclosed herein are illustrative and non-restrictive in every respect. The scope of the present invention is defined by the terms of the claims, rather than the description above, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.

It is a schematic sectional drawing which shows an example of the pneumatic tire of this invention.

Explanation of symbols

  1 tire, 2 tread portion, 3 sidewall portion, 4 bead portion, 5 bead core, 6 carcass, 7 belt layer, 8 bead apex rubber, 9 inner liner rubber, 4G clinch rubber.

Claims (4)

30 to 100 parts by mass of silica with respect to 100 parts by mass of the rubber component containing natural rubber and / or epoxidized natural rubber, and
The following general formula (1):
(X) _n -Si-Y _(4-n) (1)
(In the above general formula (1), X represents a methoxy group or an ethoxy group, Y represents a phenyl group or a linear or branched alkyl group, and n represents an integer of 1 to 3).
The rubber composition for clinch containing 2-30 mass parts of silane compounds represented by these.   The rubber composition for clinch according to claim 1, wherein X in the general formula (1) is an ethoxy group.   The rubber composition for clinch according to claim 1 or 2, further comprising 5 to 15 parts by mass of a silane coupling agent with respect to 100 parts by mass of the silica.   A pneumatic tire provided with the clinch rubber which consists of a rubber composition in any one of Claims 1-3.

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