TW201625727A - Method for preparing a silica-filled rubber composition and the composition - Google Patents

Abstract

A silica-filled rubber composition with reduced energy loss is preferred for manufacturing a low-fuel-consumption tire. However, it is not easy to dry blend silica, and also wet blending of silica is still in study. Moreover, problems arise. For example, the water-dispensed silica is not co-coagulated with a rubber emulsion, and a general rubber drying device cannot be used since even when spray drying with low energy efficiency is employed to perform drying and co-coagulating, the generated particles is fined into powder rubber. The invention relates to a method for preparing a silica-filled rubber composition, wherein when a rubber of emulsion state (a) and a water-dispensed silica slurry (b) are mixed, co-coagulated and dried to prepare a silica-filled rubber composition, the water-dispensed silica slurry is first mixed and contacted with an emulsion-like conjugated diene rubber (c) and a aqueous solution of a polymer having an amine group or imido group, and then co-coagulated with the rubber of emulsion state (a) to form particles easy to dry with a high co-coagulation rate.

Description

Method for producing cerium oxide filled rubber composition and composition thereof

The present invention relates to a method for producing a cerium oxide filler and a rubber, and a composition thereof. It is a method for producing a ruthenium dioxide-filled rubber composition and a composition thereof, which comprises mixing a slurry of cerium oxide and an emulsified rubber, co-coagulation and drying, and containing a cerium oxide filler. By sulphurizing the cerium oxide-filled rubber composition of the present invention, it can be used for tire applications such as tire tread, tread base, carcass, tire side surface, and bead portion, and can be used in anti-vibration rubber, belt, and soft. Other industrial products and other uses.

From the standpoint of resource saving and energy saving, the demand for tires to seek low fuel consumption performance is increasing year by year. As a method for producing a low fuel consumption tire, a rubber composition obtained by using cerium oxide as a filler has been proposed. However, in the preparation of cerium oxide, a decane coupling agent is necessary, and in order to use this reagent, the temperature condition of rubber mixing is limited. Further, when rubber for tires is blended, since cerium oxide is more difficult to disperse than carbon black, there are problems in that the number of kneading steps is large and the cost is high. (Non-Patent Documents 1 and 2)

The present invention provides a method of mixing and contacting a conjugated diene rubber in an emulsified state, an aqueous solution of a polymer having an amine group or an imine group, and cerium oxide to cause rubber and cerium oxide. Co-coagulation becomes easy, and a ruthenium dioxide-filled rubber composition having a particle size suitable for drying can be produced.

[Previous Technical Literature] (Patent Literature)

Patent Document 1: Japanese Patent Publication No. Sho 38-26765

Patent Document 2: Japanese Laid-Open Patent Publication No. SHO 63-051435

Patent Document 3: Japanese Laid-Open Patent Publication No. 2005-105154

[Non-patent literature]

Non-Patent Document 1: Japan Rubber Association, 71 (9), 588 (1998)

Non-Patent Document 2: Japan Rubber Association, 74(2), 64 (2001)

As a method for producing a cerium oxide-filled rubber composition from cerium oxide and a rubber in an emulsified state, a method is known in which a mixture of the two is used and spray-drying is used to evaporate a dispersion medium, that is, water to obtain a powder. A composition of cerium oxide and rubber (Patent Document 1). However, in this method, in order to evaporate a large amount of water, much heat energy is required. Therefore, it is not suitable for large-scale industrial production. Further, in this method, since the water of the emulsion is directly vaporized and dried in the case where the salt and the surfactant which are not required as the rubber composition are contained, the rubber property in the case of vulcanization may occur. Poor situation.

There is also known a method of adding a cationic polymer or a nonionic polymer to an emulsified rubber and cerium oxide, and further adding a salt and an acid, and solidifying and drying the composition of the rubber and cerium oxide. A powdery cerium oxide-filled rubber composition was produced (Patent Document 2). However, in this method, the ruthenium dioxide-filled rubber composition becomes a powder, and if a belt dryer used in general rubber production is used to dry it, a rubber composition having a small particle size is detached from the belt. Bad conditions that cannot be dried. In order to dry the ceria-filled rubber composition in a large amount, a ceria-filled rubber composition is sought which can obtain a rubber composition having a particle diameter of from about 5 mm to about 15 mm, which is suitable for general drying equipment.

Further, a method for producing a ruthenium dioxide-filled rubber composition is known, which comprises adding a cationic polymer to an emulsified rubber and cerium oxide, and solidifying and drying by a salt and an acid. However, the rubber obtained by this method, because the compounded rubber causes early vulcanization during storage or in the processing operation before the vulcanization step, and causes premature vulcanization of the product, A specific crosslinking agent must be selected (Patent Document 3). The cerium oxide-filled rubber composition obtained by this method is limited by the crosslinking agent, and the rubber physical properties and the conditions at the time of processing when used as a rubber are also restricted, which is not preferable.

An object of the present invention is to provide a method for producing a ruthenium dioxide-filled rubber composition which is suitable for mass production of rubber in the industry and which produces a ruthenium dioxide-filled rubber composition which is easily solidified and dried, and the production method does not need to be borrowed. It is dried by an inefficient spray dryer and does not become a powdery cerium oxide and a rubber composition, and becomes an appropriately sized granule, which is easy to industrially manufacture.

In the present invention, when the rubber (a) in an emulsified state and the water-dispersed ceria slurry (b) are mixed, co-coagulated, and dried to produce a ceria-filled rubber composition, the water is dispersed in advance. The cerium oxide slurry (b) is mixed and contacted with the emulsified conjugated diene rubber (c) and the aqueous solution (d) having an amine group or an imine group, and the rubber and the polymer having an amine group will be The surface of the cerium oxide is modified, and co-coagulation of the rubber (a) and cerium oxide in an emulsified state is facilitated, and the rubber at the time of solidification is not powdery and can be a granular rubber. In this way, the drying step can be carried out by using various dryers such as a belt dryer, and the ruthenium dioxide-filled rubber composition can be produced at low cost. Further, when a crosslinking agent or a crosslinking assistant is added to the produced cerium oxide-filled rubber composition to carry out vulcanization, there is no limitation in that a specific crosslinking agent or the like is used in order to prevent premature vulcanization.

That is, the present invention relates to the following:

[1] A method for producing a ruthenium dioxide-filled rubber composition, which comprises mixing a rubber (a) in an emulsified state and a water-dispersed cerium oxide slurry (b), co-coagulation, and drying to produce a cerium oxide filling When the rubber composition The water-dispersed cerium oxide slurry (b) is mixed with the emulsified conjugated diene rubber (c) and the aqueous solution (d) having an amine group or an imine group in advance, and then contacted with the emulsified state. The rubber (a) is co-coagulated; wherein the emulsified conjugated diene rubber (c) has a conversion solid content of 100 parts by weight relative to the solid content of cerium oxide in the water-dispersed cerium oxide slurry (b). 0.1 parts to 20 parts; the converted solid content of the aqueous solution (d) of the polymer having an amine group or an imine group, which is 100 parts by weight relative to the solid content of cerium oxide in the water-dispersed cerium oxide slurry (b) , from 0.1 parts to 5 parts.

[2] The method for producing a ruthenium dioxide-filled rubber composition according to the above [1], wherein the emulsified conjugated diene rubber (c) is a conjugated diene polymer containing an amine group, and Conjugated diene polymerization of at least one of a conjugated diene polymer having a hydroxyl group, a conjugated diene polymer containing an epoxy group, and a conjugated diene polymer containing an alkoxyalkyl group Things.

[3] The method for producing a ruthenium dioxide-filled rubber composition according to [1] or [2], wherein the polymer in the aqueous solution (d) of the polymer having an amine group or an imine group is At least one polymerization of ethyleneimine, diallyldimethylamine, diallylmethylamine, hydrazine, dicyandiamide, an acrylate having an amine group, a methacrylate having an amine group, and vinylpyridine a homopolymer or copolymer; or a natural water-soluble polymer compound having an amine group or an imine group.

[4] The method for producing a ruthenium dioxide-filled rubber composition according to [1] to [3], wherein, in the water-dispersed cerium oxide slurry (b), the oxidizing agent having an average particle diameter of 100 μm or more The bismuth particles are less than 5%.

[5] A ruthenium dioxide-filled rubber composition produced by the production method according to [1] to [4].

[6] A rubber for a tire obtained by vulcanizing and molding a cerium oxide-filled rubber composition as described in [5].

According to the production method of the present invention, water-dispersed cerium oxide is previously treated with an aqueous solution of an emulsified conjugated diene rubber and a polymer having an amine group or an imine group, whereby a cerium oxide filling can be obtained. The rubber composition has a high co-solidification rate and becomes an appropriately sized particle. Further, by filling the rubber composition with the cerium oxide, a vulcanized rubber having excellent physical properties, mechanical strength, and abrasion resistance and low heat build-up of the vulcanized rubber can be obtained. The cerium oxide-filled rubber composition obtained by the present invention is a rubber composition particularly suitable for a tire. Further, when the composition of the present invention is vulcanized, there is no restriction related to the crosslinking agent.

The rubber (a) in the emulsified state of the present invention is not particularly limited, and examples thereof include a natural rubber emulsion, a synthetic natural rubber emulsion, a styrene butadiene copolymerized rubber emulsion, and a styrene isoprene copolymer rubber emulsion. Acrylonitrile butadiene copolymerized rubber emulsion, chloroprene rubber emulsion. Among these, a natural rubber emulsion and a styrene butadiene copolymerized rubber emulsion are preferred.

As the water-dispersed cerium oxide slurry (b), a water-dispersed cerium oxide slurry which is synthesized as it is, or a non-drying oxidizing agent is used. A water-dispersed cerium oxide slurry prepared by a silica cake is preferred because of high dispersibility. A cerium oxide slurry obtained by adding a base to dry cerium oxide to have a pH of 8 or more and redispersing it, a cerium oxide slurry which is precipitated by adding an acid to water glass, or water glass can also be used. When water glass is used as it is, it mixes with the specific rubber emulsion in an emulsified state, and can be utilized by precipitation by acid addition.

As a ratio of the water-dispersed cerium oxide slurry (b), the solid content of the water-dispersed cerium oxide slurry (b) is from 10 parts to 150 parts with respect to 100 parts by weight of the rubber (a) in an emulsified state. When the solid content of the water-dispersed cerium oxide slurry (b) is less than 10 parts, the rubber reinforcing effect by cerium oxide cannot be expected. In addition, when it exceeds 150 parts, the rubber composition is hardened as a cerium oxide filling material, and the particle diameter of the particles at the time of solidification is also fine.

Examples of the emulsified conjugated diene rubber (c) include an amine group-containing conjugated diene polymer, a hydroxyl group-containing conjugated diene polymer, and an epoxy group-containing conjugated diene system. A conjugated diene polymer selected from the group consisting of a polymer and an alkoxyalkyl group-containing conjugated diene polymer. The amount of the amine group-containing monomer, the hydroxyl group-containing monomer, the epoxy group-containing monomer or the alkoxyalkyl group-containing monomer copolymerized with these conjugated diene polymers is preferably a copolymer The overall amount is from 0.1% to 10% (monomer weight ratio). If it is less than 0.1%, the effect is low, and if it exceeds 10%, the softness of the rubber is lowered, and the heat generation of the vulcanized rubber is increased, and the rubber physical properties are lowered.

The average molecular weight of the emulsified conjugated diene rubber (c) is preferably 100,000 or more. Preferred examples of the conjugated diene monomer include butadiene and isoprene.

The conjugated diene polymer containing an amine group may, for example, be a copolymer of butadiene, isoprene or a monomer having an amine group.

Examples of the monomer having an amine group include a monomer having a first-stage amine group, a monomer having a second-order amine group, and a monomer having a third-order amine group. Examples of the monomer having a first-stage amine group include p-aminostyrene, amine methyl (meth)acrylate, amine ethyl (meth)acrylate, and amine propyl (meth)acrylate. Aminobutyl methacrylate or the like.

Examples of the monomer having a second-order amine group include N-methyl(meth)acrylamide, N-ethyl(meth)acrylamide, N-methylol acrylamide, and N. N-monosubstituted (meth) acrylamide such as -(4-anilinophenyl)methacrylamide.

Examples of the monomer having a third-order amine group include N,N-disubstituted amine alkyl (meth) acrylate, N,N-disubstituted amine alkyl (meth) acrylamide, and N. An N-disubstituted amino aromatic vinyl compound, a monomer having a pyridyl group, and the like.

Examples of the N,N-disubstituted amino (meth) acrylate include N,N-dimethylaminomethyl (meth) acrylate and N,N-dimethylaminoethyl (A). Acrylate, N,N-dimethylaminopropyl (meth) acrylate, N,N-dimethylaminobutyl butyl (meth) acrylate, N,N-diethylaminoethyl ( Methyl) acrylate, N,N-diethylaminopropyl (meth) acrylate, N,N-diethylamine butyl (meth) acrylate, N-methyl-N-ethylamine ethyl (meth) acrylate, N,N-dipropylamine ethyl (meth) acrylate, N,N-dibutylamine ethyl (methyl) Acrylate, N,N-dibutylaminopropyl (meth) acrylate, N,N-dibutylamine butyl (meth) acrylate, N,N-dihexylamine ethyl (methyl) Acrylate, N,N-dioctylamine ethyl (meth) acrylate, and the like. Among these, N,N-dimethylaminoethyl (meth) acrylate, N,N-diethylamine ethyl (meth) acrylate, and N,N-dipropyl are preferred. Aminoethyl (meth) acrylate.

Examples of the N,N-disubstituted amino-based aromatic vinyl compound include N,N-dimethylaminoethylstyrene, N,N-diethylamineethylstyrene, and N,N-di Propylamine ethyl styrene, N,N-dioctylamine ethyl styrene, and the like.

Examples of the monomer having a pyridyl group include 2-vinylpyridine, 4-vinylpyridine, 5-methyl-2-vinylpyridine, and 5-ethyl-2-vinylpyridine. Among these, 2-vinylpyridine, 4-vinylpyridine, and mixtures thereof are preferred.

These amine group-containing monomers can be used singly or in combination of two or more kinds.

The monomer having a hydroxyl group is a monomer having at least one first-stage, second-order or third-order hydroxyl group in one molecule. Specific examples of the hydroxyl group-containing monomer include hydroxymethyl (meth) acrylate, 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, and 3 -Hydroxypropyl (meth) acrylate, 3-chloro-2-hydroxypropyl (meth) acrylate, 3-phenoxy-2-hydroxypropyl (meth) acrylate, glycerol (Meth) acrylate, hydroxybutyl (meth) acrylate, 2-chloro-3-hydroxypropyl (meth) acrylate, hydroxyhexyl (meth) acrylate, hydroxyoctyl (meth) acrylate Ester, hydroxymethyl (meth) acrylamide, 2-hydroxypropyl (meth) acrylamide, 3-hydroxypropyl (meth) acrylamide, bis-(ethylene glycol) itaconate , di-(propylene glycol) itaconate, bis(2-hydroxypropyl)iscanate, bis(2-hydroxyethyl)concanate, bis(2-hydroxyethyl)fumarate, Bis(2-hydroxyethyl) malate, 2-hydroxyethyl vinyl ether, methylol ketene, allyl alcohol, and the like. Among these, preferred are hydroxymethyl (meth) acrylate, 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 3-hydroxypropyl (A) Acrylate, 3-phenoxy-2-hydroxypropyl (meth) acrylate, glycerol mono (meth) acrylate, hydroxybutyl (meth) acrylate, hydroxyhexyl (meth) acrylate And hydroxyoctyl (meth) acrylate, 2-hydroxypropyl (meth) acrylamide, and 3-hydroxypropyl (meth) acrylamide.

These monomers having a hydroxyl group can be used singly or in combination of two or more kinds.

The epoxy group-containing monomer is a monomer having at least one epoxy group in one molecule. Examples of the epoxy group-containing monomer include glycidyl (meth)acrylate, 3,4-epoxybutyl (meth)acrylate, and 3,4-oxycyclohexyl (methyl). Acrylate, 4-hydroxybutyl acrylate glycidyl ether, N-glycidyl (meth) acrylamide, vinyl glycidyl ether, allyl glycidyl ether, 2-methylallyl glycidyl ether , 3,4-epoxy-1-butene, 3,4-epoxy-1-methyl-1-butene, 3,4-epoxy-1-pentene, 3,4-ring Oxy-3-methyl-1-pentene, 5,6- Epoxy-1-hexene, ethylene oxide cyclohexene, styrene-p-glycidyl ether, N-[4-(2,3-epoxy-1-oxo-3-phenylpropane-1 -yl)phenyl]methacrylamide or the like. Among them, glycidyl (meth)acrylate is preferred. These epoxy group-containing monomers can be used singly or in combination of two or more kinds.

The alkoxyalkyl group-containing monomer is a monomer having at least one alkoxyalkyl group in one molecule. Examples of the alkoxyalkyl group-containing monomer include (meth)acryloxymethyltrimethoxydecane, (meth)acryloxymethyltriethoxydecane, and β-(A). Base) propylene methoxyethyl trimethoxy decane, β-(meth) propylene methoxyethyl triethoxy decane, γ-(meth) propylene methoxy propyl trimethoxy decane, γ- (Meth)acryloxypropyltriethoxydecane, γ-(meth)acryloxypropyltripropoxydecane, γ-(meth)acryloxypropyltributoxy矽, γ-(meth) propylene methoxy propyl methyl dimethoxy decane, γ-(methyl) propylene methoxy propyl ethyl dimethoxy decane, γ-(methyl) propylene oxime Oxypropyl propyl dimethoxy decane, β-propylene methoxyethyloxymethyl trimethoxy decane, γ-(β-propylene methoxyethyloxy) propyl trimethoxy decane, γ -(γ-Methyl propylene methoxypropyloxy) propyl trimethoxy decane, vinyl tri-n-butoxy decane, vinyl tri-tertiary butoxy decane, vinyl tri- or 2-butoxy Base decane, vinyl triisopropoxy decane, and the like. Among these, γ-(meth)acryloxypropyltriethoxydecane, γ-(meth)acryloxypropyltripropoxydecane, γ-(methyl group) are preferred. ) acryloxypropyl tributoxy decane, γ-(β-propylene methoxyethyloxy) propyl three Butoxy oxane, γ-(γ-methacryloxypropyloxy)propyl tributoxy decane, and vinyl alkoxy oxane; more preferably γ-(meth) propylene fluorenyloxy Propyltripropoxydecane, γ-(meth)acryloxypropyl tributoxydecane, and vinyl tri-tertiary butoxydecane. These alkoxyalkylene group-containing monomers can be used singly or in combination of two or more kinds.

As the polymer of the aqueous solution (d) having an amine group or an imine group, the conjugated diene copolymer is screened off. Examples of suitable polymers include ethylene diamine, vinylamine, diallyldimethylamine, diallylmethylamine, hydrazine, dicyandiamide, an acrylate having an amine group, and an amine group. a homopolymer polymerized by at least one of methacrylate and vinyl pyridine or a copolymer with other monomers.

Specific examples of the ethyleneimine-based polymer include "EPOMIN" (registered trademark) of Japan ZEON Co., Ltd.; a copolymer of an anthracene and an acrylate having an amine group, or The "metholoc ZP, MP, MS series" (registered trademark) of HYMO Co., Ltd. is mentioned as an amino group methacrylate type polymer. Examples of the polymer of diallyldimethylamine and diallylamine are "PAS" (registered trademark) series of NITTOBO MEDICAL Co., Ltd.; Examples thereof include a dicyandiamide-polyolefin polyamine polycondensate or a dicyandiamide-formaldehyde polycondensate. Of course, these polymers are not limited to a particular manufacturer's product.

Further, a natural water-soluble polymer compound having an amine group or an imine group can also be used. For example, a gel, gelatin, collagen peptide, casein, chitosan, etc. can be mentioned, and a commercial item can be used for either.

As a specific example, in the case of gelatin, it is a nicotine-treated gelatin ST1 (registered trademark) of Nippi Co., Ltd. or a porcine acid-treated gelatin AP-30 (registered trademark); in the case of a collagen peptide, it is a collagen of Nippi Co., Ltd. Peptide FCP-AK-G (registered trademark) or LDA aggl (registered trademark) of Gelita Sol series, casein (milk manufacturing) of Nacalai Tesque Co., Ltd. (registered trademark), Meiji FM collagen of Meiji Food Materia Co., Ltd. Protein, Sanai Chitosan (registered trademark) of Sanai Pharmaceutical Co., Ltd., etc. Of course, these natural water-soluble polymer compounds are not limited to a specific manufacturer's product.

A method for producing a cerium oxide-filled rubber composition by mixing an emulsified rubber (a) and a water-dispersed cerium oxide slurry (b), co-coagulation, and drying to produce a cerium oxide-filled rubber composition At the same time, the water-dispersed cerium oxide slurry (b) is mixed with and contacted with the emulsified conjugated diene rubber (c) and the aqueous solution (d) having an amine group or an imine group, and then emulsified. The rubber (a) is co-coagulated. The surface of the water-dispersed ceria slurry (b) is treated with an emulsified state by using an aqueous solution (d) of an emulsified conjugated diene rubber (c) and a polymer having an amine group or an imine group in advance. The co-coagulation of the rubber (a) is easy, and the ceria in the slurry and the rubber particles in the emulsion are surely a ceria-filled rubber composition. Recovery of cerium oxide and rubber The particle size of the produced cerium oxide and rubber particles can be adjusted to be suitable for drying by a belt dryer or the like.

A method of treating the surface of the water-dispersed ceria slurry (b) with an aqueous solution (d) of an emulsified conjugated diene rubber (c) and a polymer having an amine group or an imine group, from work efficiency, etc. In view of the above, it is preferred to add an emulsified conjugated diene rubber (c) to the water-dispersed cerium oxide slurry (b), followed by adding an aqueous solution of an amine group or an imine group (d) )order of. Of course, the order of addition can also be changed, or (c) and (d) can be added almost simultaneously.

As a method of mixing and contacting the water-dispersed ceria slurry (b), the emulsified conjugated diene rubber (c), and the aqueous solution (d) having a polymer having an amine group or an imine group, there is a method of borrowing A mixing method performed by agitating blades or applying a high shear force generated by a homomixer. When the particle size of the water-dispersed cerium oxide slurry (b) is small, the mixing by the stirring blade is sufficient, but the slightly coarse water-dispersed cerium oxide slurry (b) is combined with high shear force. A homomixer is preferred.

The average particle diameter of the water-dispersed ceria slurry (b) is preferably 20 μm or less, and the ceria particles of 100 μm or more are preferably 5% or less. If the cerium oxide particles of 100 μm or more exceed 5%, the mechanical properties of the vulcanized rubber may be lowered.

The ratio of the cerium oxide (b) and the emulsified conjugated diene rubber (c), the aqueous solution (d) of the polymer having an amine group or an imine group, relative to 100 parts by weight of the cerium oxide in a dry state, The emulsified conjugated diene rubber (c) is used in an amount of 0.1 parts by weight to 20 parts by weight in terms of solid content; The aqueous solution (d) of the polymer having an amine group or an imine group is used in an amount of from 0.1 part by weight to 5 parts by weight per 100 parts by weight of the dry cerium oxide.

In addition, the "parts" in this specification are all "parts by weight", and the "parts by weight" is abbreviated as "parts" below.

When the amount of the emulsified conjugated diene rubber (c) is less than 0.1 part, the particle size of the particles during solidification becomes finer, and if more than 20 parts, sulfur is added. The rubber properties will be reduced.

The amount of the aqueous solution (d) of the polymer having an amine group or an imine group is less than 0.1 part, and the amount of the cerium oxide recovered when co-coagulated with the rubber (a) in an emulsified state. Will decrease. Further, the amount of the aqueous solution (d) having a polymer of an amine group or an imine group is more than 5 parts in terms of the solid content, and may cause premature vulcanization during vulcanization.

A method in which a rubber (a) in an emulsified state is mixed with a mixture of a water-dispersed cerium oxide, an emulsified conjugated diene rubber, and an amine group or an imine group polymer which have been previously mixed and brought into contact, and co-coagulated. It can be batch or continuous. The mixing of the two can be carried out by simple mixing by mixing by a general stirring blade, followed by co-coagulation by adding a salt such as salt or an acid such as dilute sulfuric acid.

The salt to be added during co-coagulation is preferably added as little as possible, and it is preferred to use only an acid to solidify it. Further, the temperature at the time of co-coagulation is preferably from 50 to 60 °C. Further, after co-coagulation, it is preferred to use water to wash the particles and remove soap, salt or acid contained in the rubber.

In the production method of the present invention, since the aqueous solution (d) having a polymer having an amine group or an imine group is mixed and contacted, co-coagulation progresses due to the addition of a small amount of salt, and the washing treatment also becomes Easy advantage.

The particle size of the particles produced by co-coagulation is adjusted so that the stirring and pH are 5 mm to 15 mm. If the particle size of the particles is changed, the number of particles falling off the slit may become insufficient. Also, if it is larger than 15mm, the drying will be insufficient and not good.

In the continuous mode of co-coagulation, the distribution of the grain shape becomes wider than the co-coagulation of the batch mode. The pH is preferably from 4 to 7, and if it is 4 or less, the corrosion of the device due to the acid or the particle size of the resulting particles may become fine.

Drying of the granules, such as a belt dryer, blowing hot air to the granules for drying; such as a microwave irradiation dryer or a mechanical press, a stretcher or a heated roll, utilizing mechanical shearing force, Heat and pressure to dry it. Any drying method can be used, and it can also be a combined device such as a heating roller after the belt dryer.

By adding the rubber composition such as solid rubber or carbon black to the cerium oxide-filled rubber composition of the present invention, a rubber such as a plasticizer such as oil, a decane coupling agent, a vulcanization aid or a vulcanizing agent is added. The composition is kneaded, formed, and vulcanized, and can be an excellent vulcanized rubber.

Examples of the other solid rubber include solution-polymerized styrene butadiene rubber, butadiene rubber, natural rubber, synthetic natural rubber, acrylonitrile butadiene rubber, chloroprene rubber, and ethylene propylene rubber.

A rubber composition obtained by adding a crosslinking agent or the like to the cerium oxide-filled rubber composition of the present invention can be used for tire applications such as a tire tread, a tread base, a carcass, a tire side surface, and a bead portion. It is used in applications such as anti-vibration rubber, belts, and hoses, but it is particularly suitable for use on rubber for tire treads.

By adding carbon black to the cerium oxide filling rubber composition of the present invention, the antistatic property or mechanical property of the rubber can be improved. As the carbon black to be added, for example, furnace black, acetylene black, thermal black, channel black, graphite, or the like can be used. Among these, the furnace carbon black is particularly preferable, and specific examples thereof include SAF, ISAF, ISAF-HS, ISAF-LS, IISAF-HS, HAF, HAF-HS, HAF-LS, FEF, and the like. level. These carbon blacks can be used singly or in combination of two or more.

The carbon black is added in an amount of from 1 to 50 parts, preferably from 3 to 30 parts, per 100 parts of the rubber component of the cerium oxide-filled rubber composition. By adding carbon black, the antistatic property and weather resistance of the rubber composition can be improved. When the amount is 50 parts or more, the heat generation of the composition becomes large, and the dynamic properties of the crosslinked rubber are lowered.

By adding a plasticizer such as oil to the cerium oxide-filled rubber composition of the present invention, the molding process can be easily performed. As a plasticizer such as an oil to be added, an extender oil which is generally used in the rubber industry can be used, and examples thereof include a paraffin-based extender oil, an aromatic filler oil, a naphthenic filler oil, or a liquid rubber. .

The flow point of the filling oil is preferably -20 to 50 ° C, more preferably -10 to 30 ° C. Within this range, a rubber composition which is easy to stretch and has excellent balance between tensile properties and low heat build-up property can be obtained. A suitable aromatic carbon content (CA%, Kurz analysis) of the extender oil, preferably 20% or more, more preferably 25% or more, and a suitable paraffin carbon content (CP%) of the extender oil, preferably It is 55% or less, more preferably 45%. If CA% is too small, or CP% is too large, the tensile properties may become insufficient. The content of the polycyclic aromatic compound in the extender oil is preferably less than 3%. This content is determined by the IP346 method (the inspection method of The Institute of Petroleum).

As the plasticizer, a liquid rubber can be used in addition to the filling oil. Examples of the liquid rubber include liquid polyisoprene rubber, carboxyl modified liquid polyisoprene rubber, liquid polybutadiene rubber, carboxyl modified liquid polybutadiene rubber, and hydroxyl group modification. Liquid polybutadiene rubber, liquid acrylonitrile butadiene copolymerized rubber, liquid styrene butadiene copolymerized rubber, liquid styrene isoprene copolymerized rubber, and the like.

The content of the plasticizer is preferably from 1 to 50 parts, more preferably from 3 to 30 parts, per 100 parts by weight of the rubber component of the cerium oxide-filled rubber composition. If the content of the plasticizer is within this range, the viscosity of the formulation in which the cerium oxide is formulated is moderate.

By adding a decane coupling agent to the cerium oxide filling rubber composition of the present invention, the mechanical properties or durability of the rubber can be improved. As the coupling agent to be added, vinyl trimethoxy decane, vinyl triethoxy decane, γ-glycidoxypropyl methoxy decane, γ- may be mentioned. Methyl propylene methoxypropyl methoxy decane, γ-aminopropyl methoxy decane, N-β (aminoethyl) γ-aminopropyl methoxy decane, N-phenyl-γ-amine C Methoxy decane, γ-mercaptopropyl methoxy decane, bis(γ-triethoxydecylpropyl) tetrasulfide, bis(γ-triethoxydecylpropyl) disulfide, triethyl Oxyalkyl propyl isocyanate, vinyl triethoxy decane, vinyl trimethoxy decane, γ-methyl propylene methoxy propyl trimethoxy decane, γ-methyl propylene methoxy propyl methyl Dimethoxydecane, γ-glycidoxypropylmethyldiethoxydecane, γ-mercaptopropyltrimethoxydecane, γ-(polyvinylamino)-propyltrimethoxydecane, N- A decane coupling agent such as β-(aminoethyl)-γ-aminopropyltrimethoxydecane or N'-vinylbenzyl-N-trimethoxydecylpropylethylenediamine salt. These may be used alone or in combination of two or more.

The crosslinking agent and crosslinking assistant added to the cerium oxide filling rubber composition of the present invention can be used in the NR, SBR, NBR, IR of the glue dispensing data sheet (Nikkei Industry News Release, April 1987). And the crosslinking agent or crosslinking assistant exemplified in the BR project.

Specific examples of the crosslinking agent include sulfur, metal oxide, 4,4'-dithiomorpholine, thiuram polysulfide, and 2-(morpholinyl)benzothiazole. An organic oxide, a benzoquinone, an alkylphenol resin, or an amine compound, among which sulfur is preferred.

Specific crosslinking aids include stearic acid, zinc oxide, cerium compounds, thiourea compounds, thiazole compounds, sulfinamide compounds, and methyl carbamide. (thiuram) compound, dithiocarbamate, xanthate compound, polyethylene glycol, and the like.

The rubber composition of the present invention can be kneaded by using a kneader such as a roll mill or a closed mixer. After the forming process, the vulcanization is carried out, and the tires such as the tire tread, the tread base, the carcass, the side surface of the tire, and the bead portion are used, and other industrial products such as anti-vibration rubber, belts, and hoses can be used. Use, but especially suitable for use on rubber for tire tread.

The pneumatic tire of the present invention is produced by using a rubber composition of the present invention by a general method. Further, depending on the necessity, the rubber composition of the present invention containing various chemicals is extruded into a tread member at a stage where no sulfur is added, and is formed by being adhered to a tire molding machine by a general method. Formed into a green tire. The raw tire was heated and pressurized in a vulcanizer to obtain a tire. The pneumatic tire of the present invention obtained in this manner is excellent in low fuel consumption, fracture characteristics, and abrasion resistance, and is excellent in productivity because of good workability of the rubber composition.

In order to explain the present invention more specifically, the following examples and comparative examples are described, but the present invention is not limited to these examples. In addition, various physical properties in the examples and comparative examples were measured by the following methods. Also, "parts" are "parts by weight".

(1) Primary particle size of cerium oxide

It was measured by a transmission electron microscope.

(2) Specific surface area - Determination of specific surface area (SBET) by nitrogen adsorption method

The wet ceria cake was placed in a desiccator (120 ° C) and dried, and then the amount of nitrogen adsorption was measured using ASAP 2010 (model) manufactured by Micromeritics Co., Ltd., and the value of the one-point method in the relative pressure of 0.2 was used.

(3) Styrene unit amount in the copolymer: Measured in accordance with JIS K6383 (refractive index method).

(4) Ceria content

The rubber composition containing cerium oxide was burned at 500 ° C, and the amount of cerium oxide was determined from the residual ash.

(5) 300% modulus, tensile strength, stretching

It was measured in accordance with the tensile stress test method of JIS K6253.

(6) Wear resistance

Using an Akron abrasion tester, the weight after 1000 rubs and the weight loss after 1000 rubs were shown. The smaller the amount of reduction, the more excellent the abrasion resistance.

(Manufacturing example of SBR emulsion)

In a pressure-resistant reactor equipped with a stirrer, 1260 g of water, 33 g of disproportionated potassium rosinate, 0.7 g of sodium salt of a naphthalenesulfonic acid-formaldehyde condensate, 3.5 g of potassium chloride, 0.7 g of tetraethylenepentylamine, and 161 g of styrene were added. 504 g of butadiene and 1.7 g of tertiary dodecyl mercaptan.

After the temperature was lowered to 5 ° C, 1.4 g of cumene hydroperoxide and 35 g of styrene were injected to initiate polymerization.

A part of the aqueous solution was taken out every certain period of time, and the solid content was measured to determine the polymerization conversion ratio.

When the polymerization conversion ratio is about 60%, 35 g of a 10% aqueous solution of sodium dimethyldithiocarbamate is injected to terminate the polymerization. The polymerized SBR emulsion was blown with steam to drive off unreacted monomers, and the test SBR emulsion was set to have a solid content concentration of 20%. The molecular weight Mw was 370,000, Mw/Mn was 3.8, the bound styrene amount was 22.8%, the Mooney viscosity was 50, and the SBR latex had a particle diameter of 100 nm.

(Production example of an amine group-containing SBR emulsion)

In a pressure-resistant reactor equipped with a stirrer, 1260 g of water, 33 g of disproportionated potassium rosinate, 0.7 g of sodium salt of a naphthalenesulfonic acid formaldehyde condensate, 3.5 g of potassium chloride, 0.7 g of tetraethylenepentylamine, 161 g of styrene, and butyl were added. 504 g of a diene, 10 g of dimethylaminoethyl methacrylate, and 1.7 g of a tertiary dodecyl mercaptan.

After the temperature was lowered to 5 ° C, 1.4 g of cumene hydroperoxide and 35 g of styrene were injected to initiate polymerization.

A part of the aqueous solution was taken out every certain period of time, and the solid content was measured to determine the polymerization conversion ratio.

After 6.5 hours, the polymerization conversion rate was about 60%, and 35 g of a 10% aqueous solution of sodium dimethyldithiocarbamate was injected to terminate the polymerization. The unreacted monomer was removed by blowing steam into the polymerized SBR emulsion, and the rubber component concentration was set to 20%. The molecular weight Mw was 280,000, Mw/Mn was 3.5, the bound styrene amount was 22.5%, the Mooney viscosity was 35, and the SBR latex had a particle diameter of 90 nm.

(Production example of bismuth dioxide cake)

To a 1 m ³ stainless steel reaction vessel equipped with a temperature adjuster, 230 L of an aqueous solution of sodium citrate (SiO ₂ concentration: 10 g/L, molar ratio: SiO ₂ /Na ₂ O = 3.41) was added, and the temperature was raised to 85 °C. Next, it took 120 minutes to simultaneously add 440 L of 22 wt% sulfuric acid 73 L and sodium citrate aqueous solution (SiO ₂ concentration: 90 g/L, molar ratio: SiO ₂ /Na ₂ O = 3.41). After 10 minutes of ripening, it took 15 minutes to add 22% by weight of sulfuric acid 16L. In the above reaction, the temperature of the reaction liquid was maintained at 85 ° C, and the reaction liquid was often stirred while stirring, and finally a cerium oxide slurry having a pH of 3.2 in the reaction liquid was obtained. This cerium oxide slurry was washed with a filter press and filtered to obtain a cerium oxide cake having a cerium oxide solid content of 20%.

The cerium oxide powder obtained by drying a part of the obtained wet cerium oxide cake had a BET specific surface area (SBET) of 200 m ² /g, a primary particle diameter of 15 nm, and a secondary particle diameter of 10 μm. Particles above 100 μm are less than 1%.

(Example 1)

1000 g of water is added to 1000 g of cerium oxide cake having a solid content of cerium oxide, and 50 g of an amino group-containing SBR emulsion is added to a cerium oxide dispersion having a cerium oxide concentration of 10% (solid content concentration: 20%) The mixture was stirred for 5 minutes by a homomixer, and 60 g of a 10% aqueous solution of diallyldimethylamine polymer (PAS-H-5S) was added thereto, followed by stirring for 5 minutes.

In this cerium oxide-amino group-containing SBR emulsion-diallyldimethylamine polymer aqueous solution, 1818 g of SBR emulsion (solid content concentration 20%) was added and stirred, and after heating to 60 ° C, 10% was added. Dilute sulfuric acid brought the pH to 6.2 to form a co-coagulum of SBR rubber and cerium oxide. It was washed three times with water and dried at 105 °C.

The resulting particles had an average particle diameter of 8 mm, and 100% of the ceria was solidified together with the rubber.

(Example 2)

The amine group-containing SBR emulsion of Example 1 was changed to 100 g, and the aqueous diallyldimethylamine polymer solution (PAS-H-5S) was changed to 20 g.

The resulting particles had an average particle diameter of 12 mm, and 98% of the ceria was solidified together with the rubber.

(Example 3)

The amine group-containing SBR emulsion of Example 1 was changed to 20 g, and the 10% polyethylenimine (EPOMIN SP200) aqueous solution was set to 100 g.

The resulting particles had an average particle diameter of 5 mm, and 98% of the ceria was solidified together with the rubber.

(Example 4)

10 g of dimethyl methacrylate methacrylate of the production example of the amine group-containing SBR emulsion was replaced with 10 g of glycidyl methacrylate to produce a glycidyl group-containing SBR emulsion. Further, as the aqueous dispersion of cerium oxide, the commercially available cerium oxide VN3 is suspended in water, and the commercially available cerium oxide VN3 has a dried BET specific surface area (SBET) of 210 m ² /g, primary granules. The diameter was 15 nm, and the secondary particle diameter was 10 μm. The solid content of cerium oxide was set to 20% in the same manner as in Example 1.

The amine group-containing SBR emulsion of Example 1 was replaced with a glycidyl group-containing SBR emulsion, and after the cerium oxide was treated with the polyfluorene copolymer, the cerium oxide and the SBR rubber were co-coagulated.

The resulting particles had an average particle diameter of 9 mm, and 99% of the ceria was solidified together with the rubber.

(Example 5)

The SBR emulsion of Example 1 was replaced with a natural rubber emulsion having a solid content of 20%, and treated in the same manner as in Example 1.

The resulting particles had an average particle diameter of 11 mm, and 99% of the ceria was solidified together with the rubber.

(Example 6)

The cerium oxide cake of the production example of the cerium oxide cake was dried at 150 ° C to obtain powdered cerium oxide, and then water was further added to the powdered cerium oxide to form a cerium oxide slurry. The cerium oxide slurry has an average particle diameter of 40 μm and particles of 100 μm or more contain 11%. Using this cerium oxide, co-coagulation was carried out with the SBR rubber in the same manner as in Example 1.

The resulting particles had an average particle diameter of 13 mm, and 98% of the ceria was solidified together with the rubber.

(Example 7)

Instead of the 10% aqueous solution of 10% chlorinated diallyldimethylamine polymer of Example 1, it was changed to 60 g of 10% gelatin (AP-30 (trade name) manufactured by porcine acid-treated gelatin Nippi Co., Ltd.) aqueous solution. .

The resulting particles had an average particle diameter of 12 mm, and 95% of the ceria was solidified together with the rubber.

(Example 8)

The polyfluorene copolymer (Himoloc ZP-700) of Example 4 was changed to 60 g of an aqueous solution of 10% gelatin (ST1 (trade name) manufactured by Bovine Gelatin Nippi Co., Ltd.).

The resulting particles had an average particle diameter of 8 mm, and 94% of the ceria was solidified together with the rubber.

(Comparative Example 1)

The 10% aqueous diallyldimethyl dimethylamine polymer solution (PAS-H-5S) of Example 1 was not used, that is, it was carried out without using the component (d) for treating cerium oxide. In an aqueous solution of cerium oxide-amine-containing SBR emulsion, 1818 g of SBR emulsion was added and stirred, then 100 g of water containing 7.2 g of calcium chloride was added, and after heating to 60 ° C, 10% dilute sulfuric acid was added to adjust the pH to At 6 o'clock, a co-coagulated material of SBR rubber and cerium oxide was formed. It was washed three times with water and dried at 105 °C.

The resulting particles had an average particle diameter of 20 mm, and 53% of the ceria was solidified together with the rubber. The particle size of the resulting particles is large and difficult to dry, flowers The drying time of Example 1 was about 2 times. Also, about half of the cerium oxide did not co-coagulate and fell off the recycling screen.

In Table 1, when the rubber in an emulsified state was taken as 100 parts, the respective composition ratios and co-coagulation results were obtained.

B-1: cerium oxide produced in the production example of cerium oxide cake

B-2: cerium oxide formed by re-slurrying commercially available dry cerium oxide

B-3: Containing 11% of cerium oxide having a particle diameter of 100 μm or more

C-1: ABR-containing SBR emulsion

C-2: emulsion containing glycidyl group

D-1: Diallyldimethylamine polymer (PAS-H-5S) NITTOBO MEDICAL Co., Ltd.

D-2: Polyethylenimine (EPOMIN SP-200) Japan ZEON Co., Ltd.

D-3: Polyfluorene Copolymer (Himoloc ZP-700) HYMO Co., Ltd.

D-4: gelatin (porcine acid treated gelatin AP-30) manufactured by Nippi Co., Ltd.

D-5: Gelatin (Carnitine Treatment Gelatin ST1) manufactured by Nippi Co., Ltd.

(assessing of physical properties of vulcanized rubber)

In each of the examples (except for Example 5 using natural rubber) and the ceria-filled SBR rubber obtained in Comparative Example 1, a decane coupling agent, polyethylene glycol, carbon black, aromatic oil, zinc oxide, and hard were added. The fatty acid, the anti-aging agent, the vulcanization accelerator and the sulfur were kneaded according to the mixing schedule of Table 2, and sulfurized rubber was prepared by a 160 ° C press to prepare a vulcanized rubber, and the physical properties were evaluated.

Further, in each of the vulcanized rubber examples 2, 3, 4, and 5 using the cerium oxide-filled rubber composition obtained in Examples 2, 3, 4, and 6, in the above kneading, the co-coagulation was supplemented. The above-mentioned kneading was carried out by dropping an equal amount of fine ceria powder of ruthenium dioxide (55 parts by weight of 1% to 2%).

Further, in the cerium oxide-filled SBR rubber obtained in Comparative Example 1, when the above kneading was carried out, the same amount of cerium oxide (55% by weight of 47%) which was detached during co-coagulation was supplemented. Fine powder is used for kneading.

Each kneading operation was carried out as described below.

In the laboratory blending and extrusion of the Labo plastomill Banbury mixer B-600 (model) manufactured by Toyo Seiki, according to the mixing schedule of Table 2, relative to the rubber (a) 100 The bismuth dioxide (b) is added in an amount of 55 parts by weight, and a total of 364 g of cerium oxide is added to fill the SBR composition, and cerium oxide added when the amount of detachment is added, that is, rubber (a) 235 g and cerium oxide (b) 129 g were added in a total amount of 364 g. And adding bis [γ-(triethoxydecyl)propyl] tetrasulfide as a decane coupling agent, carbon black (N339), anti-aging agent 6C (N-phenyl-N-(1,3-dimethyl) Butyl)-p-phenylenediamine, stearic acid, zinc oxide, aromatic oil, and polyethylene glycol were kneaded for 3 minutes.

The rubber was taken out from the Bamburi Closed Mixer B-600, and the NOCCELER CZ (N-cyclohexyl-2-benzothiazolylsulfinamide) and NOCCELER D were added to the roller machine with sulfur and vulcanization accelerator. (diphenyl hydrazine). This was carried out to obtain a cerium oxide-filled SBR rubber composite.

The mechanical properties and the Akron wear were measured after the obtained cerium oxide-filled SBR rubber composite was sulfurized at 160 ° C for 20 minutes.

Further, in order to compare the physical properties of the vulcanized rubber of the dry-blended rubber composition of cerium oxide, a vulcanized rubber was prepared as a comparative vulcanized rubber example 2. specific In the same manner, 235 g of SBR1502 and 129 g of cerium oxide VN3 were added in a total amount of 364 g, and dry blending was carried out by a laboratory kneading extrusion Banbury internal mixer B-600, and then decane was added in the same manner as in the sulfurized rubber example 1. The coupling agent, polyethylene glycol, carbon black, aromatic oil, zinc oxide, stearic acid, anti-aging agent, vulcanization accelerator and sulfur were kneaded and sulfurized by a 160 ° C press.

Table 3 shows the results of tensile physical properties. In the case of the vulcanized rubber obtained by filling the SBR with the cerium oxide of the example, the tensile strength at the time of the fracture is higher than that of the comparative vulcanized rubber example 2, the amount of the Akron wear is small, the tensile property and the resistance are Excellent wear. From this, it is understood that the composition derived from the wet method of cerium oxide and rubber produced according to the present invention has a sulfur-adding property superior to that of the dry-blended rubber composition. Further, the viscoelastic property which is an indicator of low fuel consumption performance, that is, the value of tan δ at 60 ° C, is lower than that of the comparative vulcanized rubber example 1 and the comparative vulcanized rubber example 2. This can be said to be a rubber that has low heat generation during driving and has excellent fuel economy.

In the present invention, by dissolving the water-dispersed cerium oxide in advance using an aqueous solution of an emulsified conjugated diene rubber and a polymer having an amine group or an imine group, it is possible to form particles having a high co-solidification ratio and an appropriate size. Further, it is possible to obtain a vulcanized rubber which is excellent not only in mechanical properties of vulcanized rubber but also in mechanical strength and abrasion and low in heat build-up. The cerium oxide-filled rubber composition obtained according to the present invention is a rubber composition suitable for a tire.

Claims (6)

A method for producing a ruthenium dioxide-filled rubber composition, which comprises mixing a rubber (a) in an emulsified state and a water-dispersed cerium oxide slurry (b), co-coagulation, and drying to produce a cerium oxide-filled rubber composition At this time, the water is dispersed in the cerium oxide slurry (b) in advance, mixed with and contacted with the emulsified conjugated diene rubber (c) and the aqueous solution (d) having an amine group or an imine group, and then emulsified. The rubber (a) in the state is co-coagulated; wherein the emulsified conjugated diene rubber (c) has a converted solid content, which is relative to the solid content of cerium oxide in the water-dispersed cerium oxide slurry (b) Parts, from 0.1 parts to 20 parts; the solid content of the aqueous solution (d) of the polymer having an amine group or an imine group, relative to the solid content of cerium oxide in the water-dispersed cerium oxide slurry (b) 100 parts, from 0.1 parts to 5 parts. The method for producing a cerium oxide-filled rubber composition according to claim 1, wherein the emulsified conjugated diene rubber (c) is a conjugated diene polymer containing an amine group and a hydroxyl group-containing compound. A conjugated diene polymer comprising at least one of a conjugated diene polymer, an epoxy group-containing conjugated diene polymer, and an alkoxyalkyl group-containing conjugated diene polymer. The method for producing a cerium oxide-filled rubber composition according to claim 1 or claim 2, wherein the polymer in the aqueous solution (d) of the polymer having an amine group or an imine group is Amine, diene a homopolymer of at least one of dimethylamine, diallylmethylamine, hydrazine, dicyandiamide, an acrylate having an amine group, a methacrylate having an amine group, and a vinyl pyridine or a copolymer; or a natural water-soluble polymer compound having an amine group or an imine group. The method for producing a cerium oxide-filled rubber composition according to any one of claims 1 to 3, wherein, in the water-dispersed cerium oxide slurry (b), cerium oxide having an average particle diameter of 100 μm or more The particles are less than 5%. A ruthenium dioxide-filled rubber composition produced by the production method according to any one of claims 1 to 4. A rubber for a tire obtained by vulcanizing and molding a cerium oxide-filled rubber composition according to claim 5.