JP2007182520A - Rubber composition for tire and method for producing the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a rubber composition for tire, capable of improving high mileage, wet-grip performance and abrasion resistance of a tire in balanced state and provide a method for producing the rubber composition. <P>SOLUTION: The rubber composition for tire contains a rubber component, an aluminum silicate containing allophane and/or imogolite and silica and/or carbon black. The method for the production of the rubber composition for tire comprises a step to prepare an aqueous dispersion of the aluminum silicate, a step to prepare a wet blend by blending the aqueous dispersion with the rubber component, a step to prepare a master-batch containing the aluminum silicate by solidifying the wet blend, and a step to knead the master-batch containing the aluminum silicate with a compounding component containing silica and/or carbon black. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a tire rubber composition capable of improving the fuel efficiency, wet grip performance and wear resistance of a tire in a well-balanced manner, and a method for producing the same.

  In recent years, there has been an increasing demand for tires with excellent wet grip performance and wear resistance and low fuel consumption. For the purpose of obtaining such tires, tire rubber compositions containing silica instead of carbon black have been proposed. ing. However, due to the recent increase in interest in environmental conservation, the supply of tires with even lower fuel consumption is desired, and it is necessary to supply tires with a better balance between fuel efficiency, wet grip performance and wear resistance. It has become.

Patent Document 1 discloses a rubber component, kM ¹ · xSiO _y · zH ₂ O (for the purpose of obtaining a rubber composition that maintains low heat build-up without reducing workability and wear resistance and is excellent in wet grip performance. In the formula, M ¹ is at least one metal selected from the group consisting of Al, Mg, Ti and Ca, or an oxide or hydroxide of the metal, k is an integer of 1 to 5, and x is 0 10 integer, y is 2-5 integer, and z is an inorganic compound powder represented by a is) integer of 0, carbon black, _{and, (C n H 2n + 1} O) 3 -Si _{- (CH 2) m -S l} - (CH 2) m -Si- (C n H 2n + 1 O) 3 ( wherein, n an integer of 1 to 3, m is an integer of 1 to 4, l is It is the number of sulfur atoms in the polysulfide part, and the average value of l is a positive number of 2.1 to 3.5) A rubber composition for a tire tread obtained by simultaneously mixing a ring agent at 120 to 200 ° C. has been proposed.

Patent Document 2 discloses kM ¹ · xSiO _y · zH ₂ O (formula) for the purpose of obtaining a rubber composition for a tire tread that can greatly improve wet skid performance without deteriorating wear resistance and rolling resistance characteristics. M ¹ is at least one metal selected from the group consisting of Al, Mg, Ti, and Ca, an oxide of the metal or a hydroxide of the metal, k is an integer of 1 to 5, and x is 0 A rubber composition for tire treads containing an inorganic compound powder, carbon black, silica, and a silane coupling agent, represented by an integer of 10 to 10, y is an integer of 2 to 5, and z is an integer of 0 to 10. Proposed.

In Patent Document 3, for the purpose of obtaining a rubber composition excellent in fuel efficiency and wet grip performance, kM ₁ · xSiO _y · zH ₂ O (wherein M ₁ is Al, Mg, At least one metal selected from the group consisting of Ti and Ca, an oxide or hydroxide of the metal, k is an integer of 1 to 5, x is an integer of 0 to 10, and y is an integer of 2 to 5 , Z is an integer of 0 to 10), and a rubber composition containing carbon black and / or silica, wherein the rubber component and carbon black and / or silica are mixed There has been proposed a method for producing a rubber composition comprising the steps of: and then mixing the inorganic compound powder.

However, in the means described in Patent Documents 1 to 3, it is necessary to blend a relatively large amount of inorganic compound powder in order to obtain sufficient effects of improving wet grip performance and fuel consumption, in which case wear resistance decreases. Therefore, it has been necessary to obtain a tire rubber composition that is further excellent in the balance of wet grip performance, wear resistance, and low fuel consumption.
JP 2002-338750 A JP 2003-55503 A JP 2005-213353 A

  An object of the present invention is to solve the above-mentioned problems and to provide a tire rubber composition capable of improving the low fuel consumption, wet grip performance and wear resistance of a tire in a well-balanced manner and a method for producing the same. To do.

  The present invention relates to a tire rubber composition containing at least a rubber component, an aluminum silicate containing allophane and / or imogolite, and silica and / or carbon black.

The present invention also relates to a rubber composition for tires in which the rubber component contains natural rubber.
The present invention also relates to a tire rubber composition in which the aluminum silicate includes allophane, and the allophane has a hollow sphere having an average diameter of 2 to 20 nm.

  In the present invention, the aluminum silicate includes imogolite, and the imogolite has an average outer diameter in the range of 1 to 5 nm, an average inner diameter in the range of 0.5 to 2.0 nm, and an average length. The present invention relates to a rubber composition for tires which is a hollow tube within a range of 30 nm to 5 μm.

  The present invention also relates to a tire rubber composition in which the content of the aluminum silicate is in the range of 1 to 100 parts by mass with respect to 100 parts by mass of the rubber component.

The present invention also provides, as the above silica, silica nitrogen adsorption specific surface area in the range of 100 to 500 m ² / g, and / or, as the above carbon black, the nitrogen adsorption specific surface area of 50 to 250 m ² / and a carbon black having a DBP oil absorption of 60 to 150 ml / 100 g in a range of g.

The tire rubber composition of the present invention is preferably crosslinked with sulfur.
The present invention is also a production method for obtaining the rubber composition for tires described above, the step of preparing an aqueous dispersion of the aluminum silicate, and blending the aqueous dispersion with an unvulcanized rubber component. And kneading the wet blend, solidifying the wet blend to prepare an aluminum silicate-containing masterbatch, and the aluminum silicate-containing masterbatch and a compounding component containing silica and / or carbon black. And a process for producing a rubber composition for tires.

  The present invention also relates to a method for producing a tire rubber composition in which the unvulcanized rubber component is blended with an aqueous dispersion in an emulsion state.

  The present invention also relates to a method for producing a tire rubber composition, wherein the emulsion is natural rubber latex or modified natural rubber latex.

  According to the present invention, a nanocomposite having good physical properties is formed by including an aluminum silicate containing allophane and / or imogolite having a nanometer-level microstructure in a tire rubber composition. . Therefore, by using the rubber composition for tires, it is possible to provide a pneumatic tire having excellent wet grip performance and wear resistance and low fuel consumption.

  The rubber composition for tires of the present invention contains at least a rubber component, an aluminum silicate containing allophane and / or imogolite, and silica and / or carbon black. Allophane and imogolite are both naturally occurring, and are viscous minerals made of aluminum silicate containing silicon, aluminum, oxygen, and hydrogen as main constituent elements, and have a quasicrystalline structure. Allophane is generally obtained as a layered body having a hollow spherical shell having a diameter of about 5.0 nm, and imogolite is generally obtained as a hollow tubular body having an outer diameter of about 2.0 to 2.5 nm.

  Allophane and / or imogolite is a fine structure at the nanometer level as described above, and in the present invention, by adding aluminum silicate containing allophane and / or imogolite to the rubber composition, the aluminum silicate Nanocomposites with salt as filler can be formed. Thereby, in the rubber composition for tires of the present invention, it is possible to ensure good wear resistance and wet grip performance without impairing fuel economy and processability even with a relatively small amount of filler added. Can do.

  Allophane and imogolite blended in the present invention are naturally produced in rocks, riverbed sediments, soil, etc., but can also be synthesized. In the present invention, it is more preferable to use a synthetic product in terms of few impurities. As a method for synthesizing allophane and imogolite, a conventionally known method can be employed. Specific methods are described in, for example, “Viscosity Science” Vol. 25, No. 2, pages 53 to 60 (1985). There is.

  Typical methods for synthesizing allophane and imogolite include, for example, a method in which an aqueous monosilicic acid solution and an aluminum salt aqueous solution are mixed to form an allophane or imogolite precursor and then heated to precipitate allophane or imogolite. Can be done. Here, allophane and imogolite can be selectively produced by adjusting the molar ratio of Si / Al and the pH (for example, the molar ratio of NaOH / Al) contained in the mixed solution of the monosilicate aqueous solution and the aluminum salt aqueous solution. is there.

  When the aluminum silicate mix | blended in this invention contains the allophane which is a hollow sphere, it is preferable that an average diameter shall be in the range of 2-20 nm. When the average diameter is 2 nm or more, the allophane tends to have a good effect as a reinforcing agent. When the average diameter is 20 nm or less, the reinforcing effect of the rubber composition is good even when the allophane is added in a relatively small amount. Tend to be.

  When the aluminum silicate blended in the present invention contains imogolite, the average outer diameter of the imogolite having a hollow tubular shape is preferably in the range of 1 to 5 nm. When the average outer diameter is 1 nm or more, the effect of the imogolite as a reinforcing agent tends to be good, and when it is 5 nm or less, the reinforcing effect of the rubber composition is good even when the amount of the imogolite added is relatively small. Tend to be.

  The average inner diameter of the imogolite is preferably in the range of 0.5 to 2.0 nm. When the average inner diameter is 0.5 nm or more, the effect of the imogolite as a reinforcing agent tends to be good, and when it is 2.0 nm or less, the rubber composition is reinforced even if the amount of the imogolite added is relatively small. The effect tends to be good.

  Furthermore, the average length of the imogolite is preferably in the range of 30 nm to 5 μm. When the average length is 30 nm or more, the effect of the imogolite as a reinforcing agent tends to be good, and when it is 5 μm or less, the reinforcing effect of the rubber composition is obtained even when the amount of imogolite added is relatively small. Tend to be good.

  In addition, the average diameter of allophane can be calculated as, for example, the number average value of the diameters of 20 allophane particles measured from an observation image of a TEM (transmission electron microscope). Similarly, the average outer diameter, average inner diameter, and average length of imogolite are the same for each of the outer diameter, inner diameter, and length of 20 imogolite particles measured from, for example, an observation image of a TEM (transmission electron microscope). It can be calculated as the number average value.

  The aluminum silicate blended in the present invention may be composed only of allophane and / or imogolite, but may contain aluminum silicate other than allophane and imogolite. In this case, the content of allophane and / or imogolite in the aluminum silicate is 20% by mass or more in that it is possible to achieve high compatibility between wear resistance and wet grip performance and low fuel consumption. It is preferably 30% by mass or more, more preferably 50% by mass or more.

  The content of the aluminum silicate blended in the present invention is in the range of 1 to 100 parts by mass, further in the range of 2 to 60 parts by mass, and in the range of 3 to 40 parts by mass with respect to 100 parts by mass of the rubber component. It is preferable to be within. When the content is 1 part by mass or more, the effect of improving wear resistance and wet grip performance and the effect of reducing fuel consumption can be obtained satisfactorily, and when the content is 100 parts by mass or less, there is a risk that the workability is lowered. Few.

  Examples of the rubber component of the present invention include polybutadiene rubber (BR), styrene-butadiene rubber (SBR), ethylene-propylene-diene rubber (EPDM), chloroprene rubber (CR), acrylonitrile-butadiene rubber (NBR), butyl rubber (IIR) and the like. Can be used as one or a mixture of two or more. The ethylene-propylene-diene rubber (EPDM) contains a third diene component in the ethylene-propylene rubber (EPM). Here, as the third diene component, a non-conjugated diene having 5 to 20 carbon atoms, such as 1, In addition to 4-pentadiene, 1,4-hexadiene, 1,5-hexadiene, 2,5-dimethyl-1,5-hexadiene and 1,4-octadiene, 1,4-cyclohexadiene, cyclooctadiene, dicyclopentadiene In addition, cyclic dienes such as 5-ethylidene-2-norbornene, 5-butylidene-2-norbornene, 2-methallyl-5-norbornene and 2-isopropenyl-5-norbornene can be used. In particular, the rubber component preferably contains natural rubber.

  The rubber composition of the present invention contains silica and / or carbon black. Both silica and carbon black act as a reinforcing agent for the rubber composition, and by adding these, the abrasion resistance of the rubber composition can be improved.

Silica preferably has a nitrogen adsorption specific surface area of 100 to 500 m ² / g, more preferably 110 to 450 m ² / g. When the nitrogen adsorption specific surface area is 100 m ² / g or more, the wear resistance is good, and when it is 500 m ² / g or less, the workability is good. Moreover, it is preferable that the compounding quantity of a silica shall be in the range of 20-80 mass parts with respect to 100 mass parts of rubber components, and also in the range of 30-70 mass parts. When the blending amount is 20 parts by mass or more, the wear resistance is good, and when it is 80 parts by mass or less, the fuel consumption reduction effect of the pneumatic tire is good.

The carbon black preferably has a nitrogen adsorption specific surface area of 50 to 250 m ² / g and a DBP oil absorption of 60 to 150 ml / 100 g. When the nitrogen adsorption specific surface area is 50 m ² / g or more and the DBP oil absorption is 60 ml / 100 g or more, the wear resistance is good, the nitrogen adsorption specific surface area is 250 m ² / g or less and the DBP oil absorption is 150 ml. When it is / 100 g or less, the rubber composition for tires does not become too hard. Moreover, it is preferable that the compounding quantity of carbon black shall be in the range of 20-80 mass parts with respect to 100 mass parts of rubber components, and also in the range of 30-70 mass parts. When the blending amount is 20 parts by mass or more, the wear resistance is good, and when it is 80 parts by mass or less, the fuel consumption reduction effect of the pneumatic tire is good.

  The proportion of the amount of aluminum silicate in the tire rubber composition of the present invention is preferably in the range of 1 to 80% by mass of the sum of the amounts of aluminum silicate and silica and / or carbon black. . When the proportion of the blending amount is in the range of 1 to 80% by mass, the balance between wear resistance, wet grip performance and fuel efficiency is good.

  In the present invention, when silica is blended, a silane coupling agent is preferably used in combination, for example, bis (3-triethoxysilylpropyl) disulfide, bis (3-triethoxysilylpropyl) tetrasulfide, bis (3 -Trimethoxysilylpropyl) tetrasulfide, bis (2-triethoxysilylethyl) tetrasulfide, 3-trimethoxysilylpropyl-N, N-dimethylthiocarbamoyl tetrasulfide, 3-trimethoxysilylpropylbenzothiazole tetrasulfide, 3 -Sulfuric silane coupling agents such as triethoxysilylpropyl methacrylate monosulfide; mercapto silane coupling agents such as 3-mercaptopropyltriethoxysilane and 2-mercaptoethyltrimethoxysilane Agents, 3-chloropropyltriethoxysilane, 3-nitropropyltriethoxysilane, 3-trimethoxysilylpropylmethacrylate monosulfide, etc., among others, exhibiting an excellent coupling effect and obtained by blending silica. It is preferable to use a sulfide-based silane coupling agent from the viewpoint of further improving the effect of improving wet grip performance and wear resistance and reducing rolling resistance, and in particular, bis (3-triethoxysilylpropyl) disulfide, bis It is preferable to use (3-triethoxysilylpropyl) tetrasulfide (Si69).

  It is preferable that the compounding quantity of a silane coupling agent shall be 2-20 mass% with respect to the compounding quantity of a silica. When the blending amount is 2% by mass or more, a coupling effect can be obtained satisfactorily, and the resulting pneumatic tire has good wear resistance, low fuel consumption, and wet grip performance. Moreover, when it is 20 mass% or less, sufficient coupling effect can be acquired, without impairing the workability at the time of manufacture.

  The rubber composition for tires of the present invention includes paraffinic, olefinic, aromatic and other process oils, as well as liquid paraffin, petroleum asphalt, petroleum jelly such as petroleum jelly, castor oil, linseed oil, rapeseed oil, coconut oil, etc. Oils such as fatty oils may be blended. Examples of commercially available oils include Process X-260 (aromatic oil) manufactured by Japan Energy.

Furthermore, the following compounding components can be appropriately blended in the rubber composition of the present invention.
As the vulcanizing agent blended in the present invention, an organic peroxide-based vulcanizing agent or a sulfur-based vulcanizing agent can be used, but sulfur is used because it can achieve both high wet grip performance and high wear resistance. It is preferably crosslinked and a sulfur vulcanizing agent is preferably used. Note that a sulfur-based vulcanizing agent and an organic peroxide-based vulcanizing agent may be used as a mixture. Examples of organic peroxide vulcanizing agents include benzoyl peroxide, dicumyl peroxide, 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 (benzoylperoxy) hexane, 2,5-dimethyl-2,5-di (t-butylperoxy) Oxy) hexyne-3 or 1,3-bis (t-butylperoxypropyl) benzene, di-t-butylperoxy-diisopropylbenzene, t-butylperoxybenzene, 2,4-dichlorobenzoyl peroxide, 1, 1-di-t-butylperoxy-3,3,5-trimethylsiloxane, n-butyl And the like can be used 4,4--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.

Vulcanization accelerators include sulfenamide, thiazole, thiuram, thiourea, guanidine, dithiocarbamic acid, aldehyde-amine, aldehyde-ammonia, imidazoline, or xanthate vulcanization accelerators. It is possible to use one containing at least one of them. Specifically, for example, CBS (N-cyclohexyl-2-benzothiazylsulfenamide), TBBS (N-tert-butyl-2-benzothiazylsulfenamide), N, N-dicyclohexyl-2-benzothia Dilsulfenamide, N-oxydiethylene-2-benzothiazylsulfenamide, N, N
-Sulfenamide compounds such as diisopropyl-2-benzothiazole sulfenamide, MBT (2-mercaptobenzothiazole), MBTS (dibenzothiazyl disulfide), sodium salt, zinc salt, copper salt of 2-mercaptobenzothiazole, Thiazole compounds such as cyclohexylamine salt, 2- (2,4-dinitrophenyl) mercaptobenzothiazole, 2- (2,6-diethyl-4-morpholinothio) benzothiazole, TMTD (tetramethylthiuram disulfide), tetraethylthiuram Thiuram compounds such as disulfide, tetramethylthiuram monosulfide, dipentamethylenethiuram disulfide, and thiourea compounds such as diethylthiourea, dibutylthiourea, trimethylthiourea, diortolylthiourea Guanidine compounds such as diphenylguanidine, diortolylguanidine, triphenylguanidine, orthotolylbiguanide, diphenylguanidine phthalate, zinc ethylphenyldithiocarbamate, zinc butylphenyldithiocarbamate, sodium dimethyldithiocarbamate, zinc dimethyldithiocarbamate, diamyldithiocarbamine Dithiocarbamate compounds such as zinc acid, zinc dipropyldithiocarbamate, zinc pentamethylenedithiocarbamate and piperidine, hexadecyl (or octadecyl) isopropyldithiocarbamate, sodium diethyldithiocarbamate, selenium dimethyldithiocarbamate, tellurium diethyldithiocarbamate, Acetaldehyde-aniline reactant, butyl alcohol Dehydride-aniline condensates, aldehyde-amine compounds such as hexamethylenetetramine, acetaldehyde-ammonia reactant, aldehyde-ammonia compounds, imidazoline compounds such as 2-mercaptoimidazoline, xanthate compounds such as zinc dibutylxanthate, etc. Can be used.

  In addition, the rubber composition for tires of the present invention may appropriately contain compounding agents such as zinc oxide, stearic acid, antioxidants, waxes, pressure-sensitive adhesives, inorganic fillers, plasticizers, and vulcanization accelerators. it can. As softeners, oils such as process oils, lubricating oils, paraffins, liquid paraffins, petroleum asphalts, petroleum jelly and the like added as oil components (C), fats such as castor oil, linseed oil, rapeseed oil, coconut oil, etc. In addition to oil-based softeners, fatty acids such as linoleic acid, palmitic acid and lauric acid can be used.

  As the antioxidant, amine-based, phenol-based, and imidazole-based compounds, carbamic acid metal salts, waxes, and the like can be used. As the adhesive, adhesives such as rosin resin, terpene resin, terpene phenol resin, phenol resin, coumarone indene resin, petroleum resin and the like can be used.

  As plasticizers, DMP (dimethyl phthalate), DEP (diethyl phthalate), DBP (dibutyl phthalate), DHP (diheptyl phthalate), DOP (dioctyl phthalate), DINP (diisononyl phthalate), DIDP (phthalate) Diisodecyl acid), BBP (butylbenzyl phthalate), DLP (dilauryl phthalate), DCHP (dicyclohexyl phthalate), hydrophthalic anhydride ester, TCP (tricresyl phosphate), TEP (triethyl phosphate), TBP (tributyl phosphate), TOP (trioctyl phosphate), TCEP (tri (chloroethyl phosphate)), TDCPP (trisdichloropropyl phosphate), TBXP (trisbutoxyethyl phosphate), TCPP (tris (β-chloropropyl) phosphate) ), TPP (triphenyl phosphate), octyl diphenyl phosphate, phosphoric acid (trisisopropylphenyl), DOA (dioctyl adipate), DINA (diisononyl adipate), DIDA (diisodecyl adipate), D610A (dialkyl adipate 610) , BXA (dibutyl diglycol adipate), DOZ (di-2-ethylhexyl azelate), DBS (dibutyl sebacate), DOS (dioctyl sebacate), acetyl triethyl citrate, acetyl tributyl citrate, DBM (dibutyl maleate) , DOM (2-ethylhexyl maleate), DBF (dibutyl fumarate) and the like can be used.

  The rubber composition of the present invention can be suitably used for pneumatic tires for passenger cars, buses, trucks and the like. FIG. 1 is a cross-sectional view showing the right half of a pneumatic tire to which the present invention is applied. In FIG. 1, a pneumatic tire T has a pair of bead portions 1, a pair of sidewall portions 2, and a tread portion 3 that is continuous with both sidewall portions, and a bead core 4 embedded in the pair of bead portions 1. A carcass 5 extending between each other and a belt 6 that reinforces the tread portion 3 on the outer periphery of the carcass 5 are provided. The carcass 5 has a carcass main body portion extending between the pair of bead cores 4 and a turn-up portion 5a wound around the bead core 4 from the inner side to the outer side in the tire radial direction. The carcass 5 is made of a ply in which a radial arrangement cord of an ultrahigh strength organic fiber cord such as steel cord or aramid is coated with rubber. The rubber composition of the present invention is suitably used for a tread portion of a pneumatic tire having the above basic structure.

  The method for producing the rubber composition for tires of the present invention is not particularly limited, and can be prepared by adding aluminum silicate alone, kneading with other compounding ingredients, and further vulcanizing by a conventional method. However, a masterbatch containing the aluminum silicate and an unvulcanized rubber component is prepared in advance, and the masterbatch is kneaded and vulcanized with other compounding components containing silica and / or carbon black. It is preferable to prepare a rubber composition for use. In this case, since the dispersibility of allophane and / or imogolite in the rubber composition is improved, a nanocomposite in which allophane and / or imogolite is dispersed in the tire rubber composition at a nanometer level can be formed. This is preferable in that a pneumatic tire that is superior in grip performance and low fuel consumption can be obtained.

  The fact that allophane and / or imogolite are nano-dispersed in the tire rubber composition means that a nanocomposite is formed, for example, in morphological observation using a transmission electron microscope (TEM). It is possible to evaluate by the method of confirming that most of the particles are dispersed at the nanometer level, that is, less than 1 μm. It can be evaluated by a method for confirming that the area occupied by the aggregated particles on the observation image is 50% or less of the area occupied by all the particles of allophane and / or imogolite on the observation image.

  The mass ratio (A) / (B) between the aluminum silicate (A) and the unvulcanized rubber component (B) in the aluminum silicate-containing masterbatch is in the range of 0.01 to 0.6, particularly 0.05. It is preferable to be within the range of -0.3. When the mass ratio (A) / (B) is 0.01 or more, it is preferable in terms of good reinforcement, and when it is 0.6 or less, particularly 0.3 or less, the dispersibility of the aluminum silicate is ensured. This is preferable.

  When preparing the above-mentioned aluminum silicate-containing masterbatch, the aluminum silicate is in the state of an aqueous dispersion in which the solid content concentration is, for example, in the range of 0.5 to 50% by mass, particularly in the range of 1 to 30% by mass. It is preferably blended with an unvulcanized rubber component. When the solid content concentration is 0.5% by mass or more, it is preferable in terms of easy solidification, and when it is 50% by mass or less, it is preferable in terms of ensuring good dispersibility of the aluminum silicate.

  In particular, it is possible to prepare an aluminum silicate-containing masterbatch by wet blending an aqueous dispersion of an aluminum silicate containing allophane and / or imogolite and an emulsion of an unvulcanized rubber component, followed by solidification. It is preferable in terms of improving the dispersibility of the salt.

  As the emulsion of the unvulcanized rubber component, natural rubber latex or modified natural rubber latex, SBR latex, BR latex, MBR latex and the like can be used, but natural rubber latex or modified natural rubber latex is preferable. Among these, as the modified natural rubber latex, for example, epoxidized natural rubber latex, maleic acid-modified natural rubber latex and the like can be used.

[Example]
EXAMPLES Hereinafter, although an Example is given and this invention is demonstrated in detail, this invention is not limited to these.

<Synthesis of allophane>
Dissolve 0.2083 g (0.2216 ml) of (C ₂ H ₅ O) ₄ Si in 200 ml of distilled water to prepare a 2.0 mM aqueous solution of (C ₂ H ₅ O) ₄ Si and stir at room temperature for 1 hour. The aqueous solution A was prepared by performing hydrolysis. Separately, 0.4829 g of AlCl ₃ .6H ₂ O is dissolved in 200 ml of distilled water to prepare a 4.0 mM aqueous solution of AlCl ₃ .6H ₂ O, and the mixture is stirred for 1 hour at room temperature for hydrolysis. Then, an aqueous solution B was prepared.

  The aqueous solution A was added to the aqueous solution B and mixed at room temperature for 5 minutes. Further, 60 ml of aqueous NaOH solution was added to adjust the NaOH / Al molar ratio to 3.0, whereby a cloudy solution was obtained. 40 ml of distilled water was added to this solution, stirred for 10 minutes at room temperature, heated to 96 ° C., heated in the range of 96-98 ° C. for 43 hours, cooled to room temperature, decanted at room temperature, and the supernatant Was discarded, followed by centrifugation and decantation at room temperature. Distilled water was added to the residue, and ultrasonic cleaning was performed several times at room temperature. Centrifugation and decantation were further performed at room temperature, and the supernatant was discarded to obtain an allophane aqueous dispersion having a solid content concentration of 5% by mass. The allophane aqueous dispersion was freeze-dried to obtain a dried product.

<Synthesis of imogolite>
Dissolve 0.1458 g (0.155 ml) of (C ₂ H ₅ O) ₄ Si in 200 ml of distilled water to prepare a 1.4 mM aqueous solution of (C ₂ H ₅ O) ₄ Si and stir at room temperature for 1 hour. The aqueous solution A was prepared by performing hydrolysis. Separately, 0.2897 g of AlCl ₃ .6H ₂ O is dissolved in 200 ml of distilled water to prepare a 2.4 mM aqueous solution of AlCl ₃ .6H ₂ O and stirred for 1 hour at room temperature for hydrolysis. Then, an aqueous solution B was prepared.

The aqueous solution A was added to the aqueous solution B and mixed at room temperature for 5 minutes. Further, 27.5 ml of an aqueous NaOH solution was added to adjust the pH until the pH end point was in the range of 4.5 to 5.5. A solution was obtained. When 0.5 ml of HCl aqueous solution and 1.0 ml of CH ₃ COOH aqueous solution were added thereto and mixed at room temperature for 10 minutes, the solution became transparent. 71 ml of distilled water was added to this solution and stirred at room temperature for 5 minutes, the temperature was raised to 96 ° C., heated in the range of 96 to 98 ° C. for 45 hours and 40 minutes, cooled to room temperature, and then saturated brine at room temperature. 50 ml was added for gelation, and the residue was collected after filtration at room temperature. Distilled water was added to the residue, washed and filtered at room temperature, and distilled water was further added to obtain an imogolite aqueous dispersion having a solid content concentration of 2.5 mass%. The imogolite aqueous dispersion was freeze-dried to obtain a dried product.

  Details of the synthesis method of allophane and imogolite are also described in “Viscosity Science” Vol. 25, No. 2, pp. 53-60 (1985).

  The structures of the obtained allophane and imogolite were confirmed by infrared spectrum and X-ray diffraction of the dried product.

<Preparation of aluminum silicate-containing masterbatch>
The water dispersion obtained above is blended with a natural rubber latex (trade name “HYTEX” manufactured by Nomura Trading Co., Ltd.) having a solid content concentration of 60% by mass in the mass ratios shown in Table 1, respectively. And solidifying the wet blend, and an aluminum silicate-containing masterbatch (hereinafter referred to as allophane M / S) containing 10 parts by mass of allophane with respect to 100 parts by mass of natural rubber, and natural rubber 100 Aluminum silicate-containing masterbatches (hereinafter referred to as imogolite M / S) each containing 5 parts by mass of imogolite with respect to parts by mass were prepared. The obtained allophane M / S was observed for morphology by TEM.

<Preparation of tire rubber composition>
The compounding components shown in Tables 2 to 4 were kneaded at 150 ° C. for 3 minutes using Banbury, and then press vulcanized at 150 ° C. for 30 minutes to obtain a test rubber composition. In each of Tables 2 to 4, the mixing ratio is determined so that the total mass of allophane or imogolite and silica or carbon black in each example and comparative example is constant.

<Tan δ>
The test rubber composition obtained above was measured for tan δ at 0 ° C. and 70 ° C. at a frequency of 10 Hz and an amplitude of 0.5% using “MS-9150” manufactured by Ueshima Seisakusho. The larger the value of tan δ at 0 ° C., the better the wet grip performance of the tire, and the smaller the value of tan δ at 70 ° C., the lower the tire's fuel economy.

<Lambourn wear coefficient>
About the rubber composition for a test obtained above, the amount of wear was measured using a Lambourn abrasion tester manufactured by Iwamoto Seisakusho, Comparative Example 1 for Examples 1-3, and Comparative Example 2 for Examples 4-7. In Examples 8 and 9, the comparative example 3 was indexed with 100 as an index. The higher the value, the better the wear resistance.

Note 1: SBR is a solution polymerized styrene butadiene rubber manufactured by JSR.
Note 2: Silica is “Ultrasil VN3” (N ₂ SA: 210 m ² / g) manufactured by Degussa.
Note 3: Allophane commercial products are manufactured by Shinagawa Kasei Co., Ltd.
Note 4: The oil is “Diana Process AH-16” manufactured by Idemitsu Kosan Co., Ltd.
Note 5: The silane coupling agent is “Si266” manufactured by Degussa.
Note 6: Stearic acid is manufactured by NOF Corporation.
Note 7: Zinc Hana is “Zinc Oxide 2” manufactured by Mitsui Mining & Smelting Co., Ltd.
Note 8: Sulfur is powdered sulfur manufactured by Tsurumi Chemical Co., Ltd.
Note 9: Vulcanization accelerator A is “Noxeller CZ” manufactured by Ouchi Shinsei Chemical Co., Ltd.
Note 10: Vulcanization accelerator B is “Noxeller D” manufactured by Ouchi Shinsei Chemical Co., Ltd.
Note 11: Natural rubber is a latex solidified.
Note 12: Carbon black is “N220” (nitrogen adsorption specific surface area: 120 m ² / g, DBP oil absorption: 114 ml / 100 g) manufactured by Mitsubishi Chemical Corporation.

  2 and 3 are TEM images of allophane M / S. As shown in FIG. 2 and FIG. 3, it can be seen that most of the allophane in the allophane M / S is dispersed at the nanometer level.

  From the results shown in Table 2, in Example 1 in which an allophane synthetic product was blended as an aluminum silicate, Example 2 in which an allophane commercial product was blended, and Example 3 in which an imogolite synthetic product was blended, an aluminum silicate was blended. The tan δ at 0 ° C. is larger than that of Comparative Example 1 in which no rubber composition is used, and it can be seen that the wet grip performance of the pneumatic tire can be improved when the rubber compositions of Examples 1 to 3 are used. In Examples 1 to 3, tan δ at 70 ° C. is smaller than that in Comparative Example 1. When the rubber composition of Examples 1 to 3 is used, the fuel consumption of the pneumatic tire can be reduced. I understand. In Examples 1 to 3, the Lambourne wear coefficient is larger than that of Comparative Example 1, and when the rubber composition of Examples 1 to 3 is used, it is possible to improve the wear resistance of the pneumatic tire. It turns out that it is. In particular, Example 1 using an allophane synthetic product has better results of tan δ and Lambourne wear coefficient than Example 2 using an allophane commercial product. It can be seen that the improvement of the wet grip performance and wear resistance of the tire and the reduction of fuel consumption can be achieved at a higher level.

  From the results shown in Table 3, in Example 4 in which an allophane synthetic product was blended, Example 5 in which an imogolite synthetic product was blended, Example 6 in which allophane M / S was blended, and Example 7 in which imogolite M / S was blended In comparison with Comparative Example 2 in which no aluminum silicate was blended, the tan δ at 0 ° C. was large, the tan δ at 70 ° C. was small, and the Lambourn wear coefficient was large. It can be seen that when the composition is used, the wet grip performance and wear resistance of the pneumatic tire can be improved and the fuel consumption can be reduced. In particular, Examples 6 and 7 in which allophane or imogolite was blended in the state of a masterbatch have the same mass ratio of natural rubber to allophane or imogolite as Examples 4 and 5, respectively, but Example 6 is an example. 4 and Example 7 show values of tan δ at 0 ° C. and lamborn wear coefficient larger than those of Example 5, respectively. Therefore, it can be seen that by using a pre-prepared aluminum silicate-containing master batch, wet grip performance and wear resistance can be improved and fuel consumption can be reduced at a higher level.

  Tables 2 and 3 above show the case where silica is blended, while Table 4 shows the case where carbon black is blended. From the results shown in Table 4, in Example 8 in which allophane M / S was blended and in Example 9 in which imogolite M / S was blended, tan δ at 0 ° C. was compared with Comparative Example 3 in which no aluminum silicate was blended. , Tan δ at 70 ° C is small, and the Lambourn wear coefficient is large, so even when carbon black is blended, blending allophane or imogolite improves wet grip performance and wear resistance and reduces fuel consumption. It can be seen that both can be achieved at a higher level.

  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.

  By using the rubber composition for tires of the present invention, in which an aluminum silicate containing allophane and / or imogolite is blended, a pneumatic tire having excellent wet grip performance and wear resistance and low fuel consumption is provided. It becomes possible.

It is sectional drawing which shows the right half of the pneumatic tire with which this invention is applied. It is a TEM image of allophane M / S. It is a TEM image of allophane M / S.

Explanation of symbols

  1 bead part, 2 side wall part, 3 tread part, 4 bead core, 5 carcass, 5a folded part, 6 belt.

Claims (10)

  A rubber composition for a tire, comprising at least a rubber component, an aluminum silicate containing allophane and / or imogolite, and silica and / or carbon black.   The rubber composition for tires according to claim 1 in which said rubber ingredient contains natural rubber.   The tire rubber composition according to claim 1, wherein the aluminum silicate includes the allophane, and the allophane has a hollow sphere having an average diameter of 2 to 20 nm.   The aluminum silicate contains the imogolite, and the imogolite has an average outer diameter in the range of 1 to 5 nm, an average inner diameter in the range of 0.5 to 2.0 nm, and an average length in the range of 30 nm to 5 μm. The tire rubber composition according to claim 1, wherein the tire rubber composition is an inner hollow tube.   The tire rubber composition according to claim 1, wherein the content of the aluminum silicate is in the range of 1 to 100 parts by mass with respect to 100 parts by mass of the rubber component. Silica having a nitrogen adsorption specific surface area in the range of 100 to 500 m ² / g as the silica and / or nitrogen adsorption specific surface area in the range of 50 to 250 m ² / g as the carbon black and DBP The tire rubber composition according to claim 1, comprising at least carbon black having an oil absorption of 60 to 150 ml / 100 g.   The tire rubber composition according to claim 1, which is crosslinked with sulfur. It is a manufacturing method for obtaining the rubber composition for tires according to claim 1,
Preparing an aqueous dispersion of the aluminum silicate;
Blending the aqueous dispersion with an unvulcanized rubber component to prepare a wet blend;
Solidifying the wet blend to prepare an aluminum silicate-containing masterbatch;
A step of kneading the aluminum silicate-containing masterbatch and the compounding component containing the silica and / or the carbon black;
The manufacturing method of the rubber composition for tires containing this.   The method for producing a rubber composition for a tire according to claim 8, wherein the unvulcanized rubber component is blended with the aqueous dispersion in an emulsion state.   The method for producing a tire rubber composition according to claim 9, wherein the emulsion is natural rubber latex or modified natural rubber latex.

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