TW201609983A - Method for producing rubber composition, rubber composition, compound, and method for improving silica yield rate of rubber composition - Google Patents

Abstract

Provided is a method for producing a rubber composition that includes a rubber latex (A) and silica particles (B), said method including a co-coagulation step in which the rubber latex (A) and silica particles (B) are brought into contact with a coagulant (D) to cause co-coagulation, wherein, at the same time as or prior to the time when the total quantity of the rubber latex (A), the total quantity of the silica particles (B), and the total quantity of the coagulant (D) finish being inserted into a starting material system that is made to co-coagulate, a portion or the total quantity of a water-soluble polymer compound (C) is inserted. Therein, in relation to 100 parts by weight (in terms of solid content) of the rubber latex (A), the amount of silica particles (B) used is 20-200 parts by weight (in terms of solid content), the amount of the water-soluble polymer compound (C) used is 0.05-10 parts by weight (in terms of solid content), and the amount of the coagulant (D) used is 10-50 parts by weight (in terms of solid content).

Description

Method for improving yield of ruthenium dioxide in rubber composition, rubber composition, blend and rubber composition

The present invention relates to a method for producing a rubber composition having a high yield of cerium oxide. Further, the present invention relates to a rubber composition obtained by the production method, a blend containing the rubber composition, and a method for improving the yield of cerium oxide in the rubber composition.

In order to improve the strength or wear resistance of various rubber materials, a rubber composition obtained by kneading a solid rubber and carbon black particles (hereinafter referred to as a carbon dry masterbatch) has been used in various fields. Referred to as C-DMB). Further, a rubber composition obtained by kneading a solid rubber and cerium oxide particles (hereinafter referred to as a ceria dry master batch, abbreviated as Si-DMB) has also been similar to C-DMB. The material of performance is well known.

In the first half of the 1990s, tire manufacturers discovered that when Si-DMB was used in the case of the tread rubber, there was less energy loss and fuel economy. Since then, Si-DMB has been used as a loss of energy. The rubber composition is widely used for rubber products such as tread rubber or power transmission systems that are subjected to repeated deformation.

However, the cerium oxide particles have a lower chemical affinity to the solid rubber than the carbon black particles, so the Si-DMB requires a large amount in the step of uniformly dispersing the cerium oxide particles into the solid rubber, that is, the kneading step. Time and kinetic energy, and it is currently strongly expected to significantly reduce this time and kinetic energy.

As one of the means, there is proposed a method in which a water-dispersible rubber latex such as a synthetic rubber latex or a natural rubber latex, which is substituted for a solid rubber, and a water-dispersed slurry of cerium oxide particles are uniformly mixed in a liquid state in advance, and thereafter The rubber composition is solidified by an acid or an inorganic metal salt or the like, and subjected to a precipitation, dehydration, washing, and drying step in order to produce a rubber composition. The rubber composition produced by this method (hereinafter referred to as cerium oxide wet masterbatch, abbreviated as Si-WMB) is a technical concept widely known by many prior art since the 1970s.

For example, Patent Literatures 1 to 12 disclose properties of cerium oxide particles, a stirring method of a water-dispersed slurry of cerium oxide particles, use of a decane coupling agent, types of salting-out agents, and methods of use, and the like. Technical information on many aspects of WMB.

However, perhaps because the surface of the cerium oxide particles is very hydrophilic, the yield of cerium oxide particles in Si-WMB (the weight of the solid component of the cerium oxide particles remaining in Si-WMB relative to the blended The ratio of the weight fraction of the solid content of the cerium oxide particles is very low. In particular, Patent Document 11 describes that a lower yield of about 40% is obtained unless the cerium oxide particles are treated in advance without using a decane coupling agent. It is generally considered that the decane coupling agent is relatively expensive, and although it is not determined for this reason, it is currently within the scope of the inventors' knowledge that the current situation is that Si-WMB is not mass-produced on a commercial basis.

Patent Document 1: US Patent No. 3523096

Patent Document 2: US Patent No. 3686113

Patent Document 3: US Patent No. 3686219

Patent Document 4: US Patent No. 3686220

Patent Document 5: US Patent No. 3,798,451

Patent Document 6: US Patent No. 3,798,452

Patent Document 7: US Patent No. 3694398

Patent Document 8: US Patent No. 3716513

Patent Document 9: US Patent No. 3840382

Patent Document 10: US Patent No. 4002594

Patent Document 11: US Patent No. 5763388

Patent Document 12: Japanese Patent No. 5220189

It is an object of the present invention to provide a rubber composition having a high yield of cerium oxide and a method for producing the same. Further, it is an object of the invention to provide a blend containing the rubber composition. Further, it is an object of the present invention to provide a method for improving the yield of cerium oxide in a rubber composition.

The present invention provides a method for producing a rubber composition, which comprises a method for producing a rubber composition of a rubber latex (A) and cerium oxide particles (B), and comprises a rubber latex (A) and cerium oxide particles (B). a co-coagulation step of co-coagulation in contact with the coagulant (D), in which the entire rubber latex (A), all of the ceria particles (B) and all of the coagulant (D) are co-coagulated at the end At the same time as or before the time of the raw material group, part of the input Or all of the water-soluble polymer compound (C), the amount of the cerium oxide particles (B) is 20 to 200 parts by weight based on 100 parts by weight of the rubber latex (A) (calculated as solid content) (in terms of solid content) In terms of conversion, the amount of the water-soluble polymer compound (C) used is 0.05 to 10 parts by weight (calculated as solid content), and the amount of the coagulant (D) used is 10 to 50 parts by weight (calculated as solid content).

In the co-coagulation step, it is preferred that the water-soluble polymer compound (C) and the coagulant (D) are previously prepared before the rubber latex (A) and the ceria particles (B) are brought into contact with the coagulant (D). The rubber latex (A) and the cerium oxide particles (B) are brought into contact with the coagulant (D) in the presence of the water-soluble polymer compound (C).

The rubber latex (A) preferably contains an emulsion-polymerized conjugated diene rubber latex. The water-soluble polymer compound (C) preferably contains a polyalkylene oxide.

Further, the present invention also provides a rubber composition obtainable by the above production method, and a blend containing the rubber composition.

Further, the present invention provides a method for improving the yield of cerium oxide in a rubber composition, which is a oxidizing agent in a rubber composition containing a co-coagulum of a rubber latex (A) and cerium oxide particles (B). a method for yielding bismuth, and comprising co-coagulation step of coagulating rubber latex (A) and cerium oxide particles (B) with coagulant (D), in the co-coagulation step, at the end of all rubber latex (A), at the same time as or before the time when all the cerium oxide particles (B) and all the coagulating agents (D) are put into the co-coagulated raw material group, a part or all of the water-soluble polymer compound is added, and is compared with the rubber latex (A) 100 parts by weight (calculated as solid content), the amount of the cerium oxide particles (B) used is 20 to 200 parts by weight (calculated as solid content), and the amount of the water-soluble polymer compound (C) is used. Set to 0.05 to 10 parts by weight (by solid content In terms of conversion, the amount of the coagulant (D) used is 10 to 50 parts by weight (calculated as solid content).

According to the present invention, it is possible to provide a method for producing a rubber composition which can obtain a rubber composition having a high yield of cerium oxide. Further, according to the present invention, it is possible to provide a rubber composition having a high yield of cerium oxide and a blend containing the rubber composition. Further, according to the present invention, a method for improving the yield of cerium oxide in the rubber composition can be provided.

The method for producing a rubber composition according to the present embodiment is a method for producing a rubber composition of a rubber latex (A) or cerium oxide particles (B), which is characterized in that a rubber latex (A) and cerium oxide particles are used ( B) When co-coagulation is carried out in contact with the coagulant (D), the water-soluble polymer compound (C) is added before the rubber latex (A) and the ceria particles (B) are all brought into contact with the coagulant (D). And it is characterized in that the amount of the cerium oxide particles (B) is 20 to 200 parts by weight (calculated as solid content) with respect to 100 parts by weight of the rubber latex (A) (calculated as solid content), and the water solubility is high. The molecular compound (C) is used in an amount of 0.05 to 10 parts by weight (calculated as solid content), and the coagulant (D) is used in an amount of 10 to 50 parts by weight (calculated as solid content).

The rubber latex (A) may be an emulsion in which fine particles of a rubber-based polymer are stably dispersed in a solvent, and may further contain an emulsifier if necessary. As an oak Examples of the latex rubber (A) include an emulsion polymerization conjugated diene rubber emulsion, a natural rubber latex, or a modified latex thereof. Further, a solid rubber such as a solution-polymerized styrene-butadiene copolymer rubber, a solution-polymerized polybutadiene rubber, or a solution-polymerized acrylonitrile-butadiene copolymer rubber may be dissolved in a good solvent of each rubber and used. Emulsifier or surfactant A rubber latex or the like obtained by using the solution as a forced emulsion in water, and one type or two or more types may be used. Among them, the rubber latex (A) preferably contains an emulsion polymerization conjugated diene rubber latex.

As the emulsion-polymerized conjugated diene rubber latex, one or two or more kinds of known polybutadiene emulsion polymer emulsions, styrene-butadiene emulsion copolymer latex, and acrylonitrile-butadiene type can be used. Emulsified copolymer latex, styrene-butadiene-vinylpyridine emulsion copolymer latex, and the like. The emulsion-polymerized conjugated diene rubber emulsion is particularly preferably a styrene-butadiene-based emulsion copolymer latex.

Further, in the case of obtaining an emulsion copolymer emulsion, in addition to styrene, butadiene, acrylonitrile or vinylpyridine, a known copolymerizable monomer having a functional group may be copolymerized. Specific examples of such a monomer include unsaturated carboxylic acid monomers such as acrylic acid, methacrylic acid, itaconic acid, and maleic acid, and anhydrides thereof, glycidyl methacrylate, and allyl glycidol. One type or two or more types may be used for each of the unsaturated epoxy-based monomer such as an ether, a hydroxyethyl acrylate or a hydroxyethyl methacrylate-based unsaturated monomer.

The average particle diameter of the rubber-based polymer contained in the rubber latex (A) by photon correlation method is preferably from 10 nm to 200 nm, more preferably from 20 nm to 100 nm. The average particle diameter obtained by the photon correlation method of the rubber latex can be appropriately carried out by using various emulsifiers, types of polymerization initiators, amounts of use or addition methods, ratios of use of the polymerization water, and the like used in the polymerization of the rubber latex. Adjust and adjust.

The cerium oxide particles (B) may be cerium oxide obtained by a wet method. As the cerium oxide particles (B), a wet-process cerium oxide aqueous dispersion slurry produced by adding an acid or a carbon dioxide gas to a sodium citrate aqueous solution, which is formed by precipitation of cerium oxide particles, will be used. a cerium oxide water-dispersed slurry obtained by dispersing the cerium oxide powder obtained by drying the cerium oxide powder obtained by drying the wet cerium oxide aqueous slurry in water, and dispersing the dry cerium oxide powder produced by the dry method In the water, the cerium oxide-dispersed slurry is used, and one type or two or more types can be used.

The water-soluble polymer compound (C) is a compound having a viscosity average molecular weight of 100,000 to 20,000,000. The viscosity average molecular weight of the water-soluble polymer compound (C) is more preferably from 500,000 to 15 million. Examples of the water-soluble polymer compound (C) include polyalkylene oxide, polypropylene decylamine, acrylamide-unsaturated carboxylic acid salt copolymer, alkali-soluble acrylic emulsion, and the like. These may be used alone or in combination of two or more. The water-soluble polymer compound (C) is preferably a polyalkylene oxide, a polypropylene decylamine or a acrylamide-unsaturated carboxylic acid salt copolymer. The water-soluble polymer compound (C) is particularly preferably a polyalkylene oxide. The water-soluble polymer compound (C) is further preferably polyethylene oxide.

As the coagulant (D), an acid such as an inorganic acid or acetic acid; or an alkali metal, an alkaline earth metal, a sulfate of aluminum, a chloride, a hydroxide or the like can be used. Among them, sodium chloride, calcium chloride, and aluminum sulfate are preferred, and sodium chloride is more preferred.

In the production method of the present invention, it is necessary to use rubber latex (A), cerium oxide particles (B), water-soluble polymer compound (C), coagulant (D), and 100 parts by weight relative to rubber latex (A). (in terms of solid content), the amount of the cerium oxide particles (B) is 20 to 200 parts by weight (calculated as solid content), and the amount of the water-soluble polymer compound (C) is 0.05 to 10 parts by weight (calculated as solid content), and the amount of the coagulant (D) used is 10 to 50 parts by weight (calculated as solid content).

The amount of use of the cerium oxide particles (B) is 20 to 200 parts by weight (calculated as solid content), preferably 30 to 190 parts by weight, based on 100 parts by weight of the rubber latex (A) (calculated as solid content). It is more preferably 50 to 180 parts by weight (calculated as solid content) in terms of solid content. When the cerium oxide particles (B) are less than 20 parts by weight (calculated as solid content), the content of the cerium oxide is substantially small, and if it exceeds 200 parts by weight (calculated as solid content), the oxidizing is carried out. The yield of cerium particles is poor.

The amount of the water-soluble polymer compound (C) to be used is 0.05 to 10 parts by weight (calculated as solid content), preferably 0.1 to 8 parts by weight, based on 100 parts by weight of the rubber latex (A) (calculated as solid content). (calculated as solid content), more preferably 0.1 to 5 parts by weight (calculated as solid content). If the water-soluble polymer compound (C) is less than 0.05 part by weight (calculated as solid content), the yield of the cerium oxide particles is inferior, and even if it exceeds 10 parts by weight (calculated as solid content), the performance is improved. Small, it is difficult to obtain the effect commensurate with the amount added.

The amount of the coagulant (D) to be used is 10 to 50 parts by weight (calculated as solid content), preferably 10 to 45 parts by weight, based on 100 parts by weight of the rubber latex (A) (in terms of solid content). The composition of the component is preferably 10 to 40 parts by weight (calculated as solid content). If the coagulant (D) is less than 10 parts by weight (calculated as solid content), the yield of the cerium oxide particles is inferior, and even if it exceeds 50 parts by weight (calculated as solid content), the performance improvement is small. It is difficult to obtain an effect commensurate with the amount added.

In the co-coagulation step, it is important to end the time when all of the rubber latex (A), all of the ceria particles (B), and all of the coagulant (D) are put into the co-coagulated raw material group. At the same time as or before, some or all of the water-soluble polymer compound (C) is charged.

In other words, in the co-coagulation step, some or all of the water-soluble polymer is made at the same time as or before the end of the contact of all the rubber latex (A), all of the cerium oxide particles (B), and all of the coagulating agent (D). The compound (C) is contacted with at least one of the rubber latex (A), the cerium oxide particles (B), and the coagulant (D).

Further, in the co-coagulation step, when the rubber latex (A) and the cerium oxide particles (B) are brought into contact with the coagulant (D) to coagulate, the rubber latex (A) and the cerium oxide particles (B) are obtained. The all-water-soluble polymer compound (C) is added before all of the coagulant (D) is brought into contact.

That is, in the production method of the present invention, it is important to add the order of the rubber latex (A), the cerium oxide particles (B), the water-soluble polymer compound (C), and the coagulant (D), especially to the water-soluble The time point of the polymer compound (C). According to the method for producing a rubber composition, it is not necessary to carry out the purification in the middle of the co-coagulation step, and a rubber composition excellent in the yield of cerium oxide can be obtained in a shorter step.

Specific examples of the rubber latex (A), the cerium oxide particles (B), the water-soluble polymer compound (C), and the coagulant (D) include, for example, the following: (1) Injecting a rubber latex ( After the A) and the cerium oxide particles (B), the water-soluble polymer compound (C) is introduced, and finally the coagulant (D) is introduced; (2) after the rubber latex (A) and the cerium oxide particles (B) are charged, The water-soluble polymer compound (C) is started to be introduced, and then the coagulant (D) is introduced from another route; (3) after the rubber latex (A) and the water-soluble polymer compound (C) are charged, the cerium oxide particles are introduced ( B), finally put the coagulant (D); (4) After the rubber latex (A) and the water-soluble polymer compound (C) are charged, the cerium oxide particles (B) are started to be introduced, and then the coagulant (D) is introduced from other paths; (5) the dioxide is introduced. After the ruthenium particles (B) and the water-soluble polymer compound (C), the rubber latex (A) is introduced, and finally the coagulant (D) is introduced; (6) the cerium oxide particles (B) and the water-soluble polymer compound are introduced ( After C), the rubber latex (A) is started to be charged, and then the coagulant (D) is introduced from other paths; (7) after the water-soluble polymer compound (C) is introduced, the rubber latex (A) and the cerium oxide particles are introduced. (B), finally, the coagulant (D) is introduced; (8) after the water-soluble polymer compound (C) is introduced, the rubber latex (A) and the ceria particles (B) are started to be charged, and thereafter, coagulation is carried out from other paths. (D); (9) after the input of the cerium oxide particles (B), the rubber latex (A) and the water-soluble polymer compound (C), and finally the coagulant (D); (10) the input of the dioxide After the ruthenium particles (B), the rubber latex (A) and the water-soluble polymer compound (C) are started to be introduced, and then the coagulant (D) is introduced from another route; (11) the rubber latex (A) is put into the rubber latex (A). , the cerium oxide particles (B) and the water-soluble polymer compound (C) are put, and finally the coagulant (D) is put in; (12) after the rubber latex (A) is put in, the cerium oxide particles (B) and the water-soluble are started to be dissolved. a polymer compound (C), and thereafter, a coagulant (D) is introduced from another route; (13) after the rubber latex (A) and the water-soluble polymer compound (C) are charged, the cerium oxide particles (B) are introduced. a mixture of the coagulant (D); (14) after the rubber latex (A) and the water-soluble polymer compound (C) are introduced, the coagulant (D) is introduced from other paths while the ceria particles (B) are charged; (15) after the input of the cerium oxide particles (B) and the water-soluble polymer compound (C), a mixture of the rubber latex (A) and the coagulant (D); (16) the cerium oxide particles (B) After the water-soluble polymer compound (C), the rubber latex (A) is introduced while the coagulant (D) is introduced from another route; (17) after the rubber latex (A) and the ceria particles (B) are charged, a mixture of the water-soluble polymer compound (C) and the coagulant (D); (18) after the rubber latex (A) and the ceria particles (B) are charged, while the water-soluble polymer compound (C) is charged The coagulant (D) is fed from other paths.

In the present invention, in view of the yield of the cerium oxide particles, it is necessary to make the rubber latex when the rubber latex (A) and the cerium oxide particles (B) are brought into contact with the coagulant (D) to co-coagulate. The water-soluble polymer compound (C) is added before all of the (A) and cerium oxide particles (B) are brought into contact with the coagulant (D). Among them, it is more preferable to add the water-soluble polymer compound (C) to the coagulant (D) before the rubber latex (A) and the ceria particles (B) are brought into contact with the coagulant (D). The co-coagulation step is preferably carried out in water. By performing the co-coagulation step in water, the water-soluble polymer compound (C) can be dissolved in water to be more uniformly mixed with other components.

In the present invention, the conditions at the time of co-coagulation are not particularly limited, and are carried out under the conditions of a pH of usually 4 to 10. However, from the viewpoint of the yield of the cerium oxide particles, it is preferably carried out at a pH of 5 to 9. Coagulation, preferably co-coagulation at pH 6-8. Further, the temperature is usually from 0 to 99 ° C, but from the viewpoint of the yield of the cerium oxide particles, co-coagulation is preferably carried out at a temperature of from 5 ° C to 80 ° C, more preferably 10 Co-coagulation was carried out at a temperature of ° C to 60 ° C.

In the present invention, mixing can be carried out using a known mixer, mixer or the like.

The rubber composition of the present invention can be produced by water washing, dehydration, drying, or the like after co-coagulation, but the steps are not particularly limited, and a generally used method can be used. Further, in terms of further improving the yield of cerium oxide, in the production method of the present invention, it is preferred not to carry out washing.

The rubber composition of the present invention is obtained by the method for producing a rubber composition of the present invention.

The rubber composition of the present invention may be blended with a known additive. Examples of the known additives include a vulcanizing agent, a vulcanization accelerator, a vulcanization accelerating aid, a filler, a decane coupling agent, a plasticizer, an anti-aging agent, etc., and these may be used singly or in combination of two or more kinds. Form use.

Examples of the vulcanizing agent include organic sulfur compounds such as sulfur, trimethylthiourea, and N,N'-diethylthiourea.

The vulcanization accelerator is commercially available under the trade name "SOXINOL DM" (MBTS) manufactured by Sumitomo Chemical Co., Ltd., "SOXINOL PX" (ZnEPDC) manufactured by the company, "SOXINOL PZ" (ZnMDC) manufactured by the company, and manufactured by the company. "SOXINOL EZ" (ZnEDC), "SOXINOL BZ" (ZnBDC) manufactured by the company, "SOXINOL MZ" (ZnMBT) manufactured by the company, and "SOXINOL TT" (TMTD) manufactured by the company.

Examples of the vulcanization accelerating aid include fatty acids such as stearic acid, oleic acid, and cottonseed fatty acid, and metal oxides such as zinc white.

Examples of the filler include carbon black, kaolin clay, hard clay, calcium carbonate, barium sulfate, and diatomaceous earth.

The decane coupling agent is, for example, vinyl trichlorodecane, vinyl triethoxy decane, Vinyl tris(β-methoxy-ethoxy)decane, β-(3,4-epoxycyclohexyl)-ethyltrimethoxydecane, γ-glycidoxypropyltrimethoxydecane (γ) -glycidoxypropyltrimethoxysilane), γ-glycidoxypropylmethyldiethoxydecane, γ-methylpropenyloxypropyltrimethoxydecane, N-(β-aminoethyl)-γ-amino group Propyltrimethoxydecane, γ-mercaptopropyltrimethoxydecane, γ-aminopropyltrimethoxydecane, bis-(3-(triethoxyindolyl)propyl)tetrasulfide, double- (3-(Triethoxyindolyl)propyl)disulfide, γ-trimethoxymercaptopropyldimethylthioaminocarbazide tetrasulfide, γ-trimethoxydecylpropylbenzene And thiazolyl tetrasulfide and the like.

Examples of the plasticizer include a paraffinic oil, an ester oil, and an olefin oil.

The anti-aging agent is, for example, an imidazole such as 2-mercaptobenzimidazole; for example, phenyl-α-naphthylamine, N,N'-di-β-naphthyl p-phenylenediamine, N-phenyl-N'-isopropyl An amine such as a p-phenylenediamine; for example, a phenol such as di-tert-butyl-p-cresol or styrenated phenol.

Further, a blend obtained by adding an additional rubber component to the rubber composition of the present invention is suitable for producing a tread rubber. That is, in the present invention, a tread rubber can be provided by appropriately molding a blend containing the above rubber composition and an additional rubber component (a blend for a tread rubber).

The additional rubber component may be the same as or different from the rubber component derived from the rubber latex. The rubber component to be added is not particularly limited, and examples thereof include natural rubber, polyisoprene rubber, emulsion-polymerized styrene-butadiene copolymer rubber, and solution polymerization random styrene-butadiene copolymer rubber. High trans styrene-butadiene copolymerized rubber, low cis polybutadiene rubber, high cis polybutadiene rubber, high trans polybutadiene rubber, styrene-isoprene copolymerized rubber Butadiene-isoprene copolymer rubber, solution polymerization random Styrene-butadiene-isoprene copolymerized rubber, emulsion-polymerized styrene-butadiene-isoprene copolymerized rubber, emulsion-polymerized styrene-acrylonitrile-butadiene copolymerized rubber, acrylonitrile- Various diene rubbers such as butadiene copolymerized rubber, block copolymers such as polystyrene-polybutadiene-polystyrene block copolymer, and the like. These may be used alone or in combination of two or more.

The ruthenium dioxide particles (B) may be blended with the blend of the tread rubber, and an additional filler may be blended in addition thereto. As an additional filler, carbon black is mentioned, for example.

It can also be used for the blending of tread rubber with decane coupling agent, softener, plasticizer, anti-aging agent, zinc silicate, stearic acid, vulcanizing agent, vulcanization accelerator, etc. Various additives.

The blend for the tread rubber of the present invention can be obtained by kneading according to a conventional method using a commonly used Banbury mixer or a mixer such as a kneader or a rolling mill.

[Examples]

Hereinafter, the present invention will be more specifically described by way of examples. However, the invention is not limited to the following examples. Moreover, unless otherwise indicated, % or part is based on weight.

(Measurement of Polymerization Conversion Rate of Rubber Latex (A))

The reaction liquid collected from the reaction tank was weighed, dried at 150 ° C for 1 hour, and then weighed again to measure the amount of the solid content, and was calculated by the following formula.

Polymerization conversion ratio (%) = [(solid content component (g) - solid content component (g) other than the monomer contained in the reaction liquid) / monomer component amount (g) added to the reaction system] × 100

(Measurement of Average Particle Diameter by Photon Correlation Method for Rubber Latex (A))

The average particle diameter obtained by the photon correlation method of the obtained rubber latex (A) was measured. Further, FPAR-1000 (manufactured by Otsuka Electronics Co., Ltd.) (JIS Z8826) was used for the measurement.

(Production fraction of cerium oxide particles in the rubber composition, yield of cerium oxide particles)

After the produced rubber composition was added to an empty platinum crucible and weighed, the platinum crucible was placed in an electric furnace set to 800 ° C to burn the rubber composition for 10 hours. After 10 hours, the platinum crucible was taken out of the electric furnace and weighed again. Further, the difference between the weight before burning and the weight after burning is taken as the yield of the latex in the rubber composition, and the weight after burning is set as the yield of the cerium oxide particles, and the yield relative to the latex is calculated by the following formula The number of parts (calculated as solid content) of 100 parts by weight of cerium oxide particles.

Parts of the production of cerium oxide particles (parts by weight) = (yield of cerium oxide (g) / yield of latex (g)) × 100

Next, based on the calculated fractions of the cerium oxide particles (calculated as solid content) and the blending fraction of 100 parts by weight of the cerium oxide particles relative to the rubber latex (in terms of solid content conversion) The yield of the cerium oxide particles was calculated by the following formula.

Yield of cerium oxide particles = (parts of production of cerium oxide particles (parts by weight) / parts blended by weight of cerium oxide particles (parts by weight)

(Manufacture of rubber latex (A))

200 parts by weight of pure water, 4.5 parts by weight of potassium lanthanum sulphate, 0.45 parts by weight of formalin naphthalenesulfonate condensate, 74 parts by weight of butadiene, and styrene under reduced pressure in a stainless steel pressure-resistant polymerization reactor 26 parts, 0.2 parts by weight of tri-dodecyl mercaptan, 0.65 parts by weight of trisodium phosphate, ethylenediamine 0.07 parts by weight of tetraacetic acid, 0.15 parts by weight of sodium formaldehyde sulfoxylate, 0.10 parts by weight of p-menthane hydroperoxide and 0.05 parts by weight of ferrous sulfate heptahydrate, and the polymerization was started at 5 ° C. . After 6 hours from the start of the polymerization, it was confirmed that the polymerization conversion ratio had reached 0.57, and after 5 hours from the start of the polymerization, 0.5 part by weight of diethylhydroxylamine was added to stop the polymerization reaction. The polymerization conversion ratio at the time of stopping the reaction was 0.62. After the unreacted monomer was removed by steam distillation, the solid content concentration was adjusted to 20.0% by weight with pure water to obtain a rubber latex (A).

The rubber latex (A) has an average particle diameter of 60 nm obtained by a photon correlation method.

(cerium oxide particles (B))

79 parts by weight of pure water was prepared in a stainless steel container equipped with a stirrer, and 21 parts by weight of "Nipsil VN3" manufactured by Tosoh Co., Ltd. (containing about 5% by weight of water) was added while stirring to obtain a water-soluble slurry of cerium oxide (solid form). The concentration of the component was 20.0% by weight).

(Water-soluble polymer compound (C))

1 part by weight of "PEO-8" manufactured by Sumitomo Seika Co., Ltd. was dissolved in 99 parts by weight of water to obtain a 1% by weight aqueous solution of polyethylene oxide.

(coagulant (D))

D-1: A 10% by weight aqueous sodium chloride solution obtained by dissolving 10 parts by weight of sodium chloride in 90 parts by weight of pure water.

D-2: A 1% by weight aqueous solution of calcium chloride obtained by dissolving 1 part by weight of calcium chloride in 99 parts by weight of pure water.

(Manufacture of anti-aging agent emulsified water dispersion)

Adding styrenated phenol 76.3 by weight to a sheathed stainless steel container equipped with a stirrer 2 parts by weight of sodium dodecylbenzenesulfonate and 160 parts by weight of pure water, and heated to 60 ° C with warm water, stirred for 30 minutes, emulsified, and then cooled to room temperature to produce a solid component. An aqueous dispersion of an antioxidant according to a concentration of 38.5 wt%.

(Manufacture of rubber composition) Examples 1 to 4 and Comparative Examples 1 to 3

The coagulant (D) adjusted to 25 ° C was prepared in a stainless steel container equipped with a stirrer at a ratio shown in Table 1, and the water-soluble polymer compound (C) was added and stirred. To the container, a water-dispersed solution in which a rubber latex (A), cerium oxide particles (B), and an anti-aging agent emulsified aqueous dispersion were mixed was added and stirred for 15 minutes to co-coagulate to obtain a rubber composition. Thereafter, the obtained rubber composition was filtered with a 100 mesh stainless steel wire mesh, and washed three times with 60 parts by weight of warm water of 2500 parts by weight with respect to 100 parts by weight of the rubber composition. The washed residue remaining on the mesh was dried at 110 ° C for 6 hours. The fraction of cerium oxide produced and the yield of cerium oxide in the obtained rubber composition are collectively shown in Table 1.

Example 5

Adding a coagulant (D) and a water-soluble polymer compound (C) to the aqueous dispersion solution in which the rubber latex (A), the cerium oxide particles (B), and the anti-aging agent emulsion aqueous dispersion are mixed at a ratio shown in Table 1 The mixed aqueous solution was stirred for 15 minutes to co-coagulate to obtain a rubber composition. Thereafter, it was washed and dried in the same manner as in Examples 1 to 4.

Comparative example 4

The aqueous dispersion solution in which the rubber latex (A), the cerium oxide particles (B) and the anti-aging agent emulsion aqueous dispersion were mixed was added to the coagulant (D) at a ratio shown in Table 1, and stirred for 15 minutes. Thereafter, the water-soluble polymer compound (C) was added and stirred for 15 minutes to co-coagulate to obtain a rubber. Composition. Thereafter, it was washed and dried in the same manner as in Examples 1 to 4.

As is clear from Table 1, in Examples 1 to 5 in which the method for producing a rubber composition of the present invention was used, a rubber composition having a high yield of cerium oxide was obtained.

In Comparative Examples 1 to 3, the water-soluble polymer compound (C) was not contained, and a rubber composition having a high yield of cerium oxide could not be obtained. Further, in Comparative Example 4, the water-soluble polymer compound (C) was added to the aqueous dispersion obtained by mixing the rubber latex (A), the cerium oxide particles (B), and the coagulant (D), and cerium oxide could not be obtained. A higher yield rubber composition.

[Industrial availability]

As described above, according to the method for producing a rubber composition of the present invention, a rubber composition having a high yield of cerium oxide is obtained, and therefore, in the production step of the rubber composition which must be blended with cerium oxide particles, there may be Helps to greatly improve the workability and the drastic reduction of the necessary kinetic energy in the mixing step. That is, it can provide a practical system for rubber compositions excellent in environmental and energy saving. Manufacturing technology.

Claims (7)

A method for producing a rubber composition, which comprises a method for producing a rubber composition of a rubber latex (A) and cerium oxide particles (B), and comprising solidifying a rubber latex (A) and cerium oxide particles (B) a co-coagulation step in which the agent (D) is contacted and co-coagulated, and in the co-coagulation step, the entire rubber latex (A), all the ceria particles (B) and all the coagulant (D) are put into the co-coagulation raw material group. At the same time as before or before, a part or all of the water-soluble polymer compound (C) is used, and the amount of the cerium oxide particles (B) is used in terms of 100 parts by weight of the rubber latex (A) (calculated as solid content). 20 to 200 parts by weight (calculated as solid content), the amount of the water-soluble polymer compound (C) is 0.05 to 10 parts by weight (calculated as solid content), and the amount of the coagulant (D) is 10 to 50. Parts by weight (calculated as solid content). The method for producing a rubber composition according to the first aspect of the invention, wherein the water-soluble polymer compound (C) is previously prepared before the rubber latex (A) and the cerium oxide particles (B) are brought into contact with the coagulant (D). The mixture is mixed with the coagulant (D) to bring the rubber latex (A) and the ceria particles (B) into contact with the coagulant (D) in the presence of the water-soluble polymer compound (C). The method for producing a rubber composition according to claim 1 or 2, wherein the rubber latex (A) comprises an emulsion-polymerized conjugated diene rubber latex. The method for producing a rubber composition according to any one of claims 1 to 3, wherein the water-soluble polymer compound (C) comprises a polyalkylene oxide. A rubber composition obtainable by the production method according to any one of claims 1 to 4. A blend for a tread rubber comprising the rubber composition of claim 5 of the patent application. A method for improving the yield of cerium oxide in a rubber composition, which is a method for improving the yield of cerium oxide in a rubber composition containing rubber latex (A) and cerium oxide particles (B), and includes a co-coagulation step of coagulating the rubber latex (A) and the ceria particles (B) with the coagulant (D). In the co-coagulation step, all the rubber latex (A) and all the ceria particles are finished. (B) and at the same time as or before the time when the total coagulant (D) is put into the co-coagulated raw material group, a part or all of the water-soluble polymer compound (C) is added, and 100 parts by weight relative to the rubber latex (A) (in solid form) In the conversion of the component, the amount of the cerium oxide particles (B) is 20 to 200 parts by weight (calculated as solid content), and the amount of the water-soluble polymer compound (C) is 0.05 to 10 parts by weight. (in terms of solid content), the amount of the coagulant (D) used is 10 to 50 parts by weight (calculated as solid content).