JP6711076B2 - Polybutadiene rubber, method for producing the same, and rubber composition using the same - Google Patents

Description

TECHNICAL FIELD The present invention relates to a polybutadiene rubber having an improved balance of abrasion resistance and low loss useful for a rubber material, a method for producing the same, and a rubber composition using the same.

Conventionally, polybutadiene rubber has been widely used as a thermally and mechanically excellent rubber material in various fields, but with the recent sophistication of resource and energy saving needs, polybutadiene rubber is also durable (wear resistant). Property) and energy loss (low loss property) are required to be further improved. In order to solve these problems, the molecular structure of polybutadiene rubber has a narrow molecular weight distribution, a small degree of branching of the molecular chain, a large content of cis-1,4 bonds, and the like. Energetic research and development through the development of catalysts.

For example, a method for producing highly active polybutadiene having excellent stereoregularity is disclosed using a catalyst obtained from a cobalt compound, an ionic compound of a non-coordinating anion and a cation, an organoaluminum compound, and water. (Patent Document 1).

Also disclosed is a method for producing polybutadiene having a small degree of branching in the molecular chain, using a catalyst obtained from a cobalt compound, an ionic compound of a non-coordinating anion and a cation, an organoaluminum compound, water, and hydrogen. (Patent Document 2).

Further, a method for producing polybutadiene having a small degree of branching of a molecular chain is disclosed using a catalyst obtained from a cobalt compound, an ionic compound of a non-coordinating anion and a cation, and an organoaluminum compound (Patent Document 3). ..

Furthermore, a rubber composition for tires having improved processability, abrasion resistance, heat generation characteristics and strength characteristics is disclosed by using polybutadiene having a highly controlled molecular weight, molecular weight distribution, degree of branching, and cis-1,4 bond content. (Patent Document 4).

JP, 10-182726, A JP 2000-17012 A JP, 2000-17013, A Japanese Patent No. 3775510

However, in the market, there is a demand for a polybutadiene rubber having higher wear resistance and lower loss and a rubber composition using the same.

Therefore, an object of the present invention is to provide a polybutadiene rubber having high wear resistance and low loss and a rubber composition using the same.

The present invention has a peak top molecular weight (MW _p ) of 3.60×10 ⁵ or more and a molecular weight of 2.70×10 ^{6 to} 1.10×10 ^{7 in} a polystyrene-equivalent molecular weight distribution curve by GPC. A method for producing a polybutadiene rubber having an area ratio (R _a ) of 2.0% or more,
Mixing (C) an organometallic compound of Group I to III elements with (D) water in the presence of 1,3-butadiene;
By adding (A) a cobalt compound and (B) a non-coordinating anion and an ionic compound of a cation at the same time or at intervals of less than 3 minutes, the 1,3-butadiene is polymerized to give 1,4 -A step of obtaining polybutadiene,
And a step of reacting the 1,4-polybutadiene with an organohalogen compound.

The present invention relates to the polybutadiene rubber manufactured by the above manufacturing method. Further, the present invention has a peak top molecular weight (MW _p ) of 3.60×10 ⁵ or more and a molecular weight of 2.70×10 ^{6 to} 1.10×10 ^{7 in} a polystyrene-equivalent molecular weight distribution curve by GPC. It relates to a polybutadiene rubber having an area ratio (R _a ) of 2.0% or more.

The present invention relates to a rubber composition containing the above polybutadiene rubber.

According to the present invention, a polybutadiene rubber having high wear resistance and low loss and a rubber composition using the same can be provided.

<Polybutadiene rubber>
The polybutadiene rubber according to the present invention satisfies the following conditions.

(Peak top molecular weight (MW _p ))
The peak top molecular weight (MW _p ) in the polystyrene-reduced molecular weight distribution curve by gel permeation chromatography (GPC) is 3.60×10 ⁵ or more. When the peak top molecular weight (MW _p ) is 3.60×10 ⁵ or more, the polybutadiene rubber as a whole contains a large amount of high molecular weight component, and high abrasion resistance and low loss property can be realized. The peak top molecular weight (MW _p ) is preferably 3.80×10 ⁵ or more, more preferably 4.00×10 ⁵ or more, and further preferably 4.20×10 ⁵ or more. If the peak top molecular weight (MW _p ) is too large, the workability is lowered, and the dispersibility of the filler is lowered, so that the effects of improving wear resistance and low loss are adversely affected. is preferably 10 ⁵ or less, more preferably 7.00 × 10 ⁵ or less, still more preferably 5.00 × 10 ⁵ or less. The peak top molecular weight (MW _p ) means the molecular weight at the maximum position in the molecular weight distribution curve obtained by GPC measurement.

(Area ratio in the range of molecular weight 2.70×10 ^{6 to} 1.10×10 ⁷ (R _a ))
The area ratio (R _a ) in the molecular weight range of 2.70×10 ^{6 to} 1.10×10 ^{7 in} the polystyrene-equivalent molecular weight distribution curve by GPC is 2.0% or more. When the area ratio (R _a ) is 2.0% or more, the polybutadiene rubber has a reasonably high ratio of high molecular weight components, and high abrasion resistance and low loss property can be realized. Since this high molecular weight component contributes to the improvement of the workability of rubber, the improvement of wear resistance can be achieved. The area ratio (R _a ) is preferably 2.5% or more, more preferably 3.0% or more, and further preferably 3.6% or more. If the area ratio (R _a ) is too large, the workability is lowered, and the dispersibility of the filler is lowered, so that the effect of improving the wear resistance and the low loss property is adversely reduced, so that it is 8.0% or less. Is preferable, 6.0% or less is more preferable, and 5.0% or less is further preferable. The area ratio (R _a ) in the range of molecular weight 2.70×10 ^{6 to} 1.10×10 ⁷ is 2.70× with respect to the area in the entire molecular weight range in the molecular weight distribution curve obtained by GPC measurement. It means the ratio of the area in the range of 10 ^{6 to} 1.10×10 ⁷ .

(Weight average molecular weight (M _w ))
The polystyrene-equivalent weight average molecular weight M _w by GPC is preferably 5.00×10 ^{5 to} 2.00×10 ⁶ , and more preferably 6.00×10 ^{5 to} 1.50×10 ^6. , 7.00×10 ^{5 to} 1.00×10 ⁶ is more preferable. By thus having a higher weight average molecular weight than that of a general polybutadiene rubber, a polybutadiene rubber having a moderately high proportion of high molecular weight components can be obtained, and high abrasion resistance and low loss property can be realized.

(Molecular weight distribution ( _Mw / _Mn ))
The polystyrene-equivalent weight average molecular weight to number average molecular weight ratio (M _w /M _n ) by GPC is preferably 2.0 to 4.0, more preferably 2.5 to 3.5, More preferably, it is 2.8 to 3.2. When the molecular weight distribution is in a narrow range, not only the network density of the rubber compound is improved and high abrasion resistance is achieved, but also the ratio of the high molecular weight component is reasonably high and the high molecular weight component is contained as a whole. Since it is a polybutadiene rubber that can be used, higher wear resistance and lower loss can be realized.

(Cis 1,4 bond content)
The cis-1,4 bond content in the microstructure analysis is preferably 95.0 mol% or more, more preferably 97.0 mol% or more, and further preferably 97.5 mol% or more. If the cis-1,4 bond content is 95.0 mol% or more, the abrasion resistance tends to be further improved. The cis-1,4 bond content may be 100 mol %, but it is usually 99.0% or less.

(Moonie viscosity ML _1+4,100℃ )
The Mooney viscosity ML _{1+4,100° C.} is preferably 45 to 140, more preferably 60 to 120, and further preferably 70 to 100. When the Mooney viscosity ML _{1+4,100° C.} is 45 or more, the abrasion resistance and the low loss property tend to be further improved. If the Mooney viscosity ML _{1+4,100° C.} is 140 or less, the workability tends to be improved. The method for measuring ML _{1+4,100° C.} will be described in detail in Examples described later.

(5 wt% toluene solution viscosity T _cp )
The 5 wt% toluene solution viscosity T _cp is preferably 100 to 500, more preferably 200 to 400, and further preferably 250 to 350. The method for measuring T _cp will be described in detail in Examples described later.

(T _cp /ML)
The ratio T _cp /ML of the 5 wt% toluene solution T _cp and the Mooney viscosity ML _{1+4,100° C.} is preferably 2.0 to 6.0, more preferably 3.0 to 5.5. More preferably, it is 4.0 to 5.0. When T _cp /ML is 2.0 or more, the degree of branching is reduced, the number of polymer chain ends is reduced, and energy loss is reduced, so that abrasion resistance and low loss tend to be further improved. Further, when T _cp /ML is 6.0 or less, deterioration of workability can be prevented.

1,4-polybutadiene as a raw material of the polybutadiene rubber according to the present invention includes (A) a cobalt compound, (B) an ionic compound of a non-coordinating anion and a cation, and (C) an element of Group I to III of the periodic table. It can be produced by polymerizing 1,3-butadiene with a catalyst containing an organometallic compound and (D) water.

(Component (A): cobalt compound)
As the cobalt compound as the component (A), a salt or complex of cobalt is preferably used. Particularly preferred are cobalt chloride, cobalt bromide, cobalt nitrate, cobalt octylate, cobalt naphthenate, cobalt acetate, cobalt malonate and other cobalt salts, cobalt bisacetylacetonate and trisacetylacetonate, ethyl acetoacetate. Examples thereof include ester cobalt, organic base complexes such as cobalt pyridine complex and picoline complex, and cobalt ethyl alcohol complex. The cobalt compounds may be used alone or in combination of two or more.

(Component (B): ionic compound of non-coordinating anion and cation)
Examples of the non-coordinating anion constituting the ionic compound of the non-coordinating anion and the cation of the component (B) include tetra(phenyl)borate, tetra(fluorophenyl)borate, tetrakis(difluorophenyl)borate, Tetrakis(trifluorophenyl)borate, Tetrakis(tetrafluorophenyl)borate, Tetrakis(pentafluorophenyl)borate, Tetrakis(tetrafluoromethylphenyl)borate, Tetrakis(3,5-bistrifluoromethylphenyl)borate, Tetra(toluyl) Examples thereof include borate, tetra(xylyl)borate, (triphenyl, pentafluorophenyl)borate, [tris(pentafluorophenyl),phenyl]borate, and tridecahydride-7,8-dicarbaundecaborate. On the other hand, examples of the cation include a carbenium cation, an oxonium cation, an ammonium cation, a phosphonium cation, a cycloheptatrienyl cation, and a ferrocenium cation having a transition metal.

Specific examples of the carbenium cation include tri-substituted carbenium cations such as triphenyl carbenium cation and tri-substituted phenyl carbenium cation. Specific examples of the tri-substituted phenylcarbenium cation include a tri(methylphenyl)carbenium cation and a tri(dimethylphenyl)carbenium cation.

Specific examples of ammonium cations include trimethylammonium cations, triethylammonium cations, tripropylammonium cations, tributylammonium cations, trialkylammonium cations such as tri(n-butyl)ammonium cations, N,N-dimethylanilinium cations, N , N-diethylanilinium cation, N,N-dialkylanilinium cation such as N,N-2,4,6-pentamethylanilinium cation, di(i-propyl)ammonium cation, dialkylammonium such as dicyclohexylammonium cation Examples include cations.

Specific examples of the phosphonium cation include triarylphosphonium cations such as triphenylphosphonium cation, tri(methylphenyl)phosphonium cation, and tri(dimethylphenyl)phosphonium cation.

The ionic compound can be preferably used by arbitrarily selecting and combining from the non-coordinating anions and cations exemplified above. Among them, as the ionic compound, triphenylcarbenium tetrakis(pentafluorophenyl)borate, N,N-dimethylanilinium tetrakis(pentafluorophenyl)borate, 1,1′-dimethylferrocenium tetrakis(pentafluorophenyl) Borate is preferable. The ionic compounds may be used alone or in combination of two or more.

(Component (C): Organometallic compound of Group I to III elements of the periodic table)
As the organometallic compound of the group I to III elements of the periodic table of the component (C), organolithium, organomagnesium, organoaluminum and the like are used. Among them, as the organic metal compound, organic aluminum such as trialkylaluminum, dialkylaluminum chloride, dialkylaluminum bromide, alkylaluminum sesquichloride and alkylaluminum sesquibromide is preferable. Specific examples of the organic aluminum compound include trialkyl aluminum such as trimethyl aluminum, triethyl aluminum, triisobutyl aluminum, trihexyl aluminum, trioctyl aluminum and tridecyl aluminum.

Further, organoaluminum includes dialkylaluminum chlorides such as dimethylaluminum chloride and diethylaluminum chloride, organoaluminum halogen compounds (halogen-containing aluminum compounds) such as sesquiethylaluminum chloride and ethylaluminum dichloride, diethylaluminum hydride, diisobutylaluminum hydride and sesquialuminum. Also included are organoaluminum hydride compounds such as ethyl aluminum hydride. The organometallic compounds may be used alone or in combination of two or more.

(Mole ratio of each component)
The blending ratio of each component may be appropriately set according to various conditions, but the molar ratio of the component (A) and the component (B) is preferably 1:0.1-10, and 1:0.2-5. More preferable. The molar ratio of the component (A) to the component (C) is preferably 1:0.1 to 1000, more preferably 1:1 to 500. The molar ratio of the component (C) and the component (D) is preferably 1:0.01 to 2, more preferably 1:0.01 to 1.5, and further preferably 1:0.1 to 1.5. ..

(Order of addition of each component)
The order of addition of each component is preferably, for example, the following order. That is, it is preferable to add the components (C) and (D) in the presence of 1,3-butadiene to be polymerized, and then add the components (A) and (B) in any order. The component (C) and the component (D) may be added at the same time or may be added at intervals, but the component (C) is usually added after the component (D) is added. The component (A) and the component (B) may be added at the same time or may be added at intervals, but it is more preferable to add the component (B) after adding the component (A). By adding the component (D) and the component (C), a cocatalyst is formed, and thereafter, by contacting the component (A) with the cocatalyst, an effective and homogeneous active species is formed first. This is because.

However, it is preferable to add the component (A) and the component (B) simultaneously or at intervals of less than 3 minutes, more preferably at intervals of 2 minutes or less, and more preferably at intervals of 1 minute or less. It is more preferable to add after opening. If an interval of 3 minutes or more is provided, an inhomogeneous active species is formed and an ultrahigh molecular weight component is produced, and it becomes difficult to obtain polybutadiene having a desired Mz/Mw. On the contrary, when the component (A) and the component (B) are added simultaneously or at intervals of less than 3 minutes, it becomes easy to obtain a polybutadiene capable of improving the balance of breaking strength, abrasion resistance and low loss property.

(Mixing of (C) component and (D) component)
It is preferable that the component (C) and the component (D) are mixed in the presence of 1,3-butadiene and then aged. The aging temperature is preferably -50 to 80°C, more preferably -10 to 50°C. The aging time is preferably 0.01 to 24 hours, more preferably 0.05 to 5 hours, and even more preferably 0.1 to 3 hours.

Each component can be used while being supported by an inorganic compound or an organic polymer compound.

(solvent)
A solvent may be used during the polymerization. Examples of the solvent include aromatic hydrocarbon solvents such as toluene, benzene and xylene, saturated aliphatic hydrocarbon solvents such as n-hexane, butane, heptane and pentane, alicyclic hydrocarbon solvents such as cyclopentane and cyclohexane, 1- Olefinic hydrocarbon solvents such as C4 fractions such as butene, cis-2-butene, trans-2-butene, petroleum hydrocarbon solvents such as mineral spirits, solvent naphtha and kerosene, halogenated hydrocarbons such as methylene chloride A solvent etc. are mentioned. Further, 1,3-butadiene itself may be used as the polymerization solvent. Among them, benzene, cyclohexane, a mixture of cis-2-butene and trans-2-butene, etc. are preferably used.

(Molecular weight regulator)
A molecular weight modifier can be used during the polymerization. As the molecular weight modifier, non-conjugated dienes such as cyclooctadiene and allene, and α-olefins such as ethylene, propylene and butene-1 can be used. Cyclooctadiene is particularly preferred, and the amount thereof used is preferably 30 mmol or less, and more preferably 5 mmol or less, per 1 mol of 1,3-butadiene. If the amount of the molecular weight regulator exceeds this range, the problem of ML viscosity shift may occur.

(Polymerization temperature and polymerization time)
The polymerization temperature is preferably in the range of -30 to 100°C, particularly preferably in the range of 30 to 80°C. The polymerization time is preferably in the range of 10 minutes to 12 hours. The polymerization pressure is normal pressure or pressure up to about 10 atm (gauge pressure).

(Polymerization temperature and polymerization time)
The polymerization temperature is preferably in the range of -30 to 100°C, particularly preferably in the range of 30 to 80°C. The polymerization time is preferably in the range of 10 minutes to 12 hours. The polymerization pressure is normal pressure or pressure up to about 10 atm (gauge pressure).

(Reaction with organic halogen compounds)
In order to impart viscoelastic properties to the 1,4-polybutadiene obtained above, it is preferable to react 1,4-polybutadiene with an organic halogen compound. 1,4-Polybutadiene that has not been reacted with an organic halogen compound may not exhibit desired properties.

As the organic halogen compound, an organic halogen compound represented by the following formula can be used.
R ¹ R ² R ³ CX
In the formula, R ¹ is a hydrogen atom, an alkyl group, an aryl group, a chloro-substituted alkyl group, an alkoxy group, or the like, R ² is a hydrogen atom, an alkyl group, an aryl group, chloro, bromo, or the like, and R ³ is , An alkyl group, an aryl group, a vinyl group, chlorine, bromine and the like, R ² +R ³ may be an oxygen atom, and X is halogen such as chlorine, bromine and the like. When R ¹ and R ² are hydrogen atoms, R ³ is preferably an aryl group. The alkyl group may be saturated or unsaturated, may be linear, branched or cyclic, and examples thereof include an aliphatic hydrocarbon group. The alkyl group, the chloro-substituted alkyl group, and the alkoxy group preferably have 1 to 6 carbon atoms, and the aryl group preferably has 6 to 9 carbon atoms.

Specific examples of the organic halogen compound include methyl, ethyl, iso-propyl, iso-butyl, t-butyl, phenyl, benzyl, benzoyl and benzylidene chlorides or bromides. Further, methyl chloroformate, bromoformate, chlorodiphenylmethane, chlorotriphenylmethane and the like can be mentioned. Among them, t-butyl chloride or t-butyl bromide is preferable.

A cobalt compound and/or a halogen-containing aluminum compound may be added together with the above organic halogen compound. As the cobalt compound and the halogen-containing aluminum compound, the cobalt compound and the halogen-containing aluminum compound exemplified as the catalyst component can be used.

The addition amount of the organic halogen compound is preferably 1×10 ⁻⁴ to 1×10 ⁻¹ mol, and preferably 1×10 ⁻³ to 1×10 ⁻² mol, per 1 mol of 1,3-butadiene (monomer). More preferably. When the addition amount of the organic halogen compound per 1 mol of 1,3-butadiene is 1×10 ⁻⁴ or more, the effect of the present invention is easily obtained, and when it is 1×10 ⁻¹ mol or less, gelation occurs. Less likely to happen.

The reaction temperature of 1,4-polybutadiene and the organic halogen compound is preferably 20 to 100°C, more preferably 30 to 80°C.

The reaction time of 1,4-polybutadiene and the organic halogen compound is preferably 10 to 150 minutes, more preferably 15 to 30 minutes. It is preferable to stir during the reaction.

The reaction between 1,4-polybutadiene and the organic halogen compound may be carried out during the polymerization of 1,3-butadiene, but it is preferably carried out after the polymerization of 1,3-butadiene. Specifically, it is preferable to add the organohalogen compound after stopping the polymerization reaction of 1,3-butadiene with an antioxidant or the like. After the polymerization of 1,3-butadiene, the solvent and unreacted monomers contained in the polymerization solution are removed by a steam stripping method or a vacuum drying method, and the obtained dried product is dissolved again with cyclohexane or the like, and then an organic halogen compound May be added. After the reaction of 1,4-polybutadiene and the organic halogen compound, the pressure inside the reaction vessel may be released as necessary, and post-treatments such as washing and drying steps may be performed.

The polybutadiene rubber manufactured by the above manufacturing method has high wear resistance and low loss.

<Rubber composition>
The rubber composition according to the present invention contains the above-mentioned polybutadiene rubber according to the present invention. Polybutadiene rubber, alone or blended with other synthetic rubber or natural rubber, is oil-extended with a process oil if necessary, and then a reinforcing agent such as carbon black or silica, a process oil, an antioxidant, a vulcanizing agent. Various rubbers such as tires, anti-vibration rubbers, belts, hoses, seismic isolation rubbers, and other industrial products and footwear such as men's shoes, women's shoes, and sports shoes. Used for purposes. In that case, it is preferable that the rubber component contains at least 10% by weight of the polybutadiene rubber according to the present invention.

As the other synthetic rubber contained in the rubber composition, a vulcanizable rubber is preferable, and specifically, ethylene propylene diene rubber (EPDM), nitrile rubber (NBR), butyl rubber (IIR), chloroprene rubber (CR), Examples thereof include polyisoprene, high cis polybutadiene rubber, low cis polybutadiene rubber (BR), styrene-butadiene rubber (SBR), butyl rubber, chlorinated butyl rubber, brominated butyl rubber and acrylonitrile-butadiene rubber. Derivatives of these rubbers, for example, polybutadiene modified with a tin compound, rubber modified with epoxy, silane, or maleic acid can also be used. Other synthetic rubbers may be used alone or in combination of two or more.

Examples of the reinforcing agent include carbon black, silica, activated calcium carbonate, inorganic reinforcing agents such as ultrafine magnesium silicate, syndiotactic-1,2-polybutadiene resin, polyethylene resin, polypropylene resin, high styrene resin, phenol resin, lignin. , Organic reinforced agents such as modified melamine resin, coumarone indene resin and petroleum resin. Of these, carbon black is preferable. As the carbon black, carbon black having a particle size of 90 nm or less and a dibutyl phthalate (DBP) oil absorption of 70 ml/100 g or more is preferable. As the type of carbon black, for example, FEF, FF, GPF, SAF, ISAF, SRF, HAF and the like are preferably used.

As the process oil, any of aromatic type, naphthene type and paraffin type may be used.

Examples of the antiaging agent include amine/ketone type, imidazole type, amine type, phenol type, sulfur type and phosphorus type.

As the vulcanizing agent, known vulcanizing agents such as sulfur, organic peroxides, resin vulcanizing agents, and metal oxides such as magnesium oxide are used.

As the vulcanization aid, known vulcanization aids such as aldehydes, ammonias, amines, guanidines, thioureas, thiazoles, thiurams, dithiocarbamates and xanthates can be used.

Examples of the filler which is one of the other compounding agents include inorganic fillers such as calcium carbonate, basic magnesium carbonate, clay, Lissajous and diatomaceous earth, and organic fillers such as regenerated rubber and powdered rubber.

Further, as the silane coupling agent which is also one of the other compounding agents, an organosilicon compound represented by the general formula R7 _n SiX _4-n can be mentioned, and R7 is a vinyl group, an acyl group, an allyl group or an allyloxy group. An organic group having 1 to 20 carbon atoms having a reactive group selected from a group, an amino group, an epoxy group, a mercapto group, a chloro group, an alkyl group, a phenyl group, hydrogen, a styryl group, a methacryl group, an acryl group, and an ureido group. X is a hydrolyzable group selected from a chloro group, an alkoxy group, an acetoxy group, an isopropenoxy group, an amino group, and the like, and n represents an integer of 1 to 3.

R7 of the above silane coupling agent preferably contains a vinyl group and/or a chloro group. Specific silane coupling agents include, but are not limited to, the following.
Bis(3-triethoxysilylpropyl) tetrasulfide, bis(3-triethoxysilylpropyl) trisulfide, bis(3-triethoxysilylpropyl) disulfide, bis(2-triethoxysilylpropyl) tetrasulfide, bis(3 -Trimethoxysilylpropyl) tetrasulfide, bis(2-trimethoxysilylpropyl) tetrasulfide, 3-mercaptopropyltrimethoxysilane, 3-mercaptopropyltriethoxysilane, 2-mercaptoethyltrimethoxysilane, 2-mercaptoethoxysilane , 3-triethoxysilylpropyl-N,N-dimethylthiocarbamoyltetrasulfide, 3-triethoxysilylpropyl-N,N-dimethylthiocarbamoyltetrasulfide, 2-triethoxysilylethyl-N,N-dimethylthiocarbamoyltetrasulfide Sulfide, 3-trimethoxysilylpropyl benzothiazole tetrasulfide, 3-triethoxysilylpropyl benzothiazole tetrasulfide, 3-triethoxysilylpropyl methacrylate monosulfide, 3-trimethoxysilylpropyl methacrylate monosulfide, vinyl trichlorosilane, methyl vinyl Dichlorosilane, divinyldichlorosilane, dimethylvinylchlorosilane, chloromethyldimethylvinylsilane, methoxydimethylvinylsilane, trimethoxyvinylsilane, dimethyldivinylsilane, ethoxydimethylvinylsilane, diacetoxymethyldinylsilane, allyloxydimethylvinylsilane, diethoxymethylvinylsilane, bis (Dimethylamino)methylvinylsilane, phenylvinyldichlorosilane, triacetoxyvinylsilane, 3-chloropropylmethyldivinylsilane, diethoxydivinylsilane, dimethylethylmethylketokimvinylsilane, dimethylisobutoxyvinylsilane, triethoxyvinylsilane, methylphenylvinylchlorosilane, Methylphenylvinylsilane, dimethylisopentyloxyvinylsilane, 4-bromophenyldimethylvinylsilane, 3-aminophenoxydimethylvinylsilane, 4-aminophenoxydimethylvinylsilane, dimethylpiperidinomethylvinylsilane, dimethyl-2-[(2-ethoxyethoxy)ethoxy. ] Vinylsilane, divinylmethylphenoxysilane, dimethyl-P-anisylvinylsilane, tris(1-methyl) Rubinyloxy) vinylsilane, triisopropoxyvinylsilane, diethoxy-2-piperidinoethoxyvinylsilane, diphenylvinylchlorosilane, 3-dimethylvinylphenyl N,N-diethylcarbomate, triphenoxyvinylsilane, 1,3-divinyl-1,1, 3,3-tetramethyldisiloxane, 1,3-divinyl-1,1,3,3-tetramethyldisilazane, 1-(4-methylpiperidinomethyl)-1,1,3,3-tetramethyl -3-Vinyldisiloxane, 1,4-bis(dimethylvinylsilyl)benzene, 1,4-bis(dimethylvinylsiloxy)benzene, 1,3-bis(dimethylvinylsiloxy)benzene, 1,1,3,3 -Tetraphenyl-, 3-divinyldisiloxane, 1,3,5-trimethyl-1,3,5-trivinylcyclotrisiloxane, 1,3,5,7-tetramethyl-1,3,5,7- Tetravinylcyclotetrasiloxane, tetrakis(dimethylvinylsiloxymethyl)methane, 3-chloropropyltrimethoxysilane.

The amount of the silane coupling agent added is preferably 0.2 to 20% by weight, more preferably 5 to 15% by weight, based on the amount of the filler. If the added amount of the silane coupling agent is less than the above range, it may cause scorch. On the other hand, if the amount exceeds the above range, the tensile properties and the elongation may decrease.

The rubber composition can be obtained by kneading with a mixer such as an ordinary Banbury mixer or a kneader.

The polybutadiene rubber according to the present invention can also be used as a modifier for plastics such as high impact polystyrene. That is, a rubber-modified impact-resistant polystyrene resin composition containing the polybutadiene rubber according to the present invention can be produced.

As a method for producing the rubber-modified impact-resistant polystyrene-based resin composition, for example, a method of polymerizing a styrene-based monomer in the presence of a rubber-like polymer is adopted, and a bulk polymerization method or a bulk suspension polymerization method is economical. This is an advantageous method. As the styrene-based monomer, for example, styrene; alkyl-substituted styrenes such as α-methylstyrene and p-methylstyrene; halogen-substituted styrenes such as chlorostyrene are conventionally known for producing rubber-modified impact-resistant polystyrene-based resin compositions. One or a mixture of two or more of the styrenic monomers described above is used. Of these, styrene is preferable.

During the production of the rubber-modified impact-resistant polystyrene resin composition, if necessary, in addition to the rubber-like polymer, a styrene-butadiene copolymer, ethylene-propylene, ethylene-vinyl acetate, an acrylic rubber, or the like, The rubber-like polymer may be used in combination in an amount of 50% by weight or less. Moreover, you may mix the resin composition manufactured by these methods. Further, polystyrene-based resin containing no rubber-modified polystyrene-based resin composition produced by these methods may be mixed.

Explaining the above-mentioned bulk polymerization method with an example, a rubber-like polymer (1 to 25% by weight) is dissolved in a styrene monomer (99 to 75% by weight), and in some cases, a solvent, a molecular weight modifier, a polymerization initiator, etc. Is added to convert the rubbery polymer into particles dispersed in a styrene monomer conversion rate of 10 to 40%. The rubber phase forms a continuous phase until the rubber particles are generated. Further, the polymerization is continued to undergo a phase conversion (particle formation step) as a dispersed phase as rubber particles to polymerize up to a conversion rate of 50 to 99% to produce a rubber-modified impact-resistant polystyrene resin composition.

Dispersed particles of rubber-like polymer (rubber particles) are particles dispersed in a resin and consist of a rubber-like polymer and a polystyrene resin. The polystyrene-based resin may or may not be graft-bonded to the rubber-like polymer. It is stored. The diameter of the dispersed particles of the rubber-like polymer referred to in the present invention is preferably in the range of 0.5 to 7.0 μm (preferably in the range of 1.0 to 3.0 μm).

The graft ratio is preferably in the range of 150 to 350. The production may be batch type or continuous type, and is not particularly limited. The raw material solution mainly composed of the styrene-based monomer and the rubber-like polymer is polymerized in the complete mixing type reactor, but as the complete mixing type reactor, the raw material solution maintains a uniform mixed state in the reactor. Any one may be used, and preferable examples include a stirring blade of a type such as a helical ribbon, a double helical ribbon, and an anchor. It is preferable to attach a draft tube to the helical ribbon type stirring blade to further strengthen the vertical circulation in the reactor.

The rubber-modified impact-resistant polystyrene-based resin composition may include an antioxidant, a stabilizer such as an ultraviolet absorber, a release agent, a lubricant, a colorant, various fillers, and various fillers as needed during or after production. Known additives such as plasticizers, higher fatty acids, organic polysiloxanes, silicone oils, flame retardants, antistatic agents and foaming agents may be added. The rubber-modified impact-resistant polystyrene-based resin composition can be used for various known molded products, but it is excellent in flame resistance, impact resistance, and tensile strength, so it is suitable for injection molding used in electrical and industrial fields. It is suitable. For example, it can be used in a wide range of applications such as color televisions, radio-cassette recorders, word processors, typewriters, facsimiles, VTR cassettes, home appliances, industrial appliances for housings such as telephones.

Hereinafter, examples based on the present invention will be specifically described.

(Moonie viscosity (ML _1+4,100°C ))
The Mooney viscosity (ML _{1+4,100° C.} ) was measured for 4 minutes after preheating at 100° C. for 1 minute using a Mooney viscometer (trade name: SMV-200) manufactured by Shimadzu Corporation according to JIS K6300.

(Viscosity of 5 wt% toluene solution (T _cp ))
The viscosity (T _cp ) of a 5 wt% toluene solution was measured by dissolving 2.28 g of the polymer in 50 ml of toluene and then measuring the viscosity of a Canon Fenske viscometer No. 400 was used and measured at 25°C. A standard solution for calibrating viscometer (JIS Z8809) was used as the standard solution.

(GPC measurement)
The peak top molecular weight (MW _p ), area ratio (R _a ), weight average molecular weight (M _w ) and molecular weight distribution (M _w /M _n ) were determined by gel permeation chromatography at a temperature of 40° C. using tetrahydrofuran as a solvent ( It was calculated from a molecular weight distribution curve obtained by GPC (manufactured by Tosoh Corporation) using a calibration curve prepared using standard polystyrene as a standard substance. In the GPC measurement, a column was used in which two Shodex KF-805L (trade name) were connected in series, and a detector was a suggestive refractometer (RI).

(Cis 1,4 bond content)
The cis-1,4 bond content in the microstructure analysis was calculated by infrared absorption spectrum analysis. Specifically, the cis-1,4 bond content was calculated from the absorption intensity ratio of the peak position (cis: 740 cm ⁻¹ ) derived from the microstructure.

(Abrasion resistance)
As an index of the abrasion resistance of the rubber composition, the Lambourn abrasion coefficient was measured at a slip ratio of 40% according to the measuring method specified in JIS K6264, and an index (INDEX) with Comparative Example 1 as 100 was calculated. The larger this index, the better the abrasion resistance.

(Low loss)
The complex elastic modulus E ^* and tan δ, which are the viscoelasticity of the rubber composition, are measured under the conditions of a temperature of 50° C. or 70° C., a frequency of 16 Hz, and a dynamic strain of 0.2% by using EPLEXOR 100N (trade name) manufactured by GABO. As an index of the low loss property of the rubber composition, tan δ/complex elastic modulus E ^* was calculated, and an index (INDEX) with Comparative Example 1 as 100 was calculated. The larger this index is, the better the low loss property is.

(Example 1)
The inside of an autoclave having an internal volume of 1.5 L was replaced with nitrogen, 500 ml of cyclohexane and 500 ml of butadiene were charged, and the concentration of butadiene in the mixed solution was adjusted to 5.7M. The water content of cyclohexane measured by Karl Fischer was 5 ppm, the water content of butadiene was 19.4 ppm, and the water content of the mixed solution was 0.44 mM.

The temperature of this mixed solution was adjusted to 25° C., 1.78 mmol of water was added, and the mixture was stirred at 500 rpm for 30 minutes. Further, 4.9 mmol of cyclooctadiene (COD) and 2.38 mmol of triethylaluminum (TEA) were added, and 1.5 minutes later, heating to 65° C. was started. Five minutes after the addition of triethylaluminum, 6.0 μmol of cobalt octenoate (Co(Oct) ₂ ) was added in the state of a toluene solution, and 10 seconds later, triphenylcarbonium tetrakis(pentafluorophenyl)borate (Ph ₃ CB( C ₆ F ₅ ) ₄ ) was added in a toluene solution in an amount of 12.0 μmol, and the mixture was polymerized at 65° C. for 30 minutes. The Mooney viscosity (ML _{1+4,100° C.} ) of the obtained 1,4-polybutadiene was 58.1.

After polymerization for 30 minutes, after adding 0.03 mmol of the antioxidant in the state of a cyclohexane solution, 0.30 mmol of t-butyl chloride was added, and 30 seconds after that, 0.235 mmol of diethylaluminum chloride was added, and at 50°C. Reacted for 35 minutes.

Then, 0.94 mmol of an antioxidant was added in the state of an ethanol solution, and the mixture was stirred for 2 minutes, then ethanol was added to the obtained polymerization liquid to recover a polybutadiene rubber. Next, the recovered polybutadiene rubber was vacuum dried at 100° C. for 1 hour. Table 1 shows the physical properties of the obtained polybutadiene rubber.

30 parts by weight of the obtained polybutadiene rubber (BR) and 70 parts by weight of natural rubber (ML=70) were put into a 250 cc Laboplast mill preheated to 90° C. and kneaded for 1 minute. Next, 50 parts by weight of carbon black (ISAF, manufactured by Mitsubishi Chemical, trade name: Diablack I), 3 parts by weight of oil (manufactured by H&R, trade name: VivaTec 400), 3 parts by weight of zinc oxide (ZnO#1), stearin. 2 parts by weight of an acid (manufactured by Shin Nippon Rika) and 2 parts by weight of an antioxidant (manufactured by Ouchi Shinko, trade name: Nocrac 6C) were mixed and kneaded for 4 minutes. After a total of 5 minutes had elapsed since the start of the kneading, the kneaded product was taken out from the Labo Plastomill. Next, while winding the taken out mixture around a 6-inch roll and kneading the rolls, 1.5 parts by weight of powdered sulfur which is a vulcanizing agent and a vulcanization accelerator (manufactured by Ouchi Shinko Kagaku Kogyo, trade name: NOXCELLER NS) 1 part by weight was added and mixed for about 5 minutes. Next, press vulcanization was performed at a temperature of 150° C., and the resulting vulcanized test pieces were used to evaluate wear resistance and low loss. The evaluation results are shown in Table 1.

(Example 2)
A polybutadiene rubber was produced in the same manner as in Example 1 except that the amount of t-butyl chloride was 0.20 mmol and the amount of diethylaluminum chloride was 0.157 mmol, and the abrasion resistance was the same as in Example 1. And low loss property were evaluated. Table 1 shows the physical properties of the obtained polybutadiene rubber, and the evaluation results of abrasion resistance and low loss.

(Comparative Example 1)
A commercially available BR710 manufactured by Ube Industries, Ltd. was used as the polybutadiene rubber, and the abrasion resistance and the low loss property were evaluated in the same manner as in Example 1. The evaluation results are shown in Table 1.

(Comparative example 2)
The inside of an autoclave having an internal volume of 1.5 L was replaced with nitrogen, 500 ml of cyclohexane and 500 ml of butadiene were charged, and the concentration of butadiene in the mixed solution was adjusted to 5.7M. The water content of cyclohexane measured by Karl Fischer was 5 ppm, the water content of butadiene was 19.4 ppm, and the water content of the mixed solution was 0.44 mM.

The temperature of this mixed solution was adjusted to 25° C., 1.78 mmol of water was added, and the mixture was stirred at 500 rpm for 30 minutes. Further, 4.9 mmol of cyclooctadiene (COD) and 2.38 mmol of triethylaluminum (TEA) were added, and 1.5 minutes later, heating to 65° C. was started. Five minutes after the addition of triethylaluminum, 6.0 μmol of cobalt octenoate (Co(Oct) ₂ ) was added in the state of a toluene solution, and 10 seconds later, triphenylcarbonium tetrakis(pentafluorophenyl)borate (Ph ₃ CB( C ₆ F ₅ ) ₄ ) was added in a toluene solution in an amount of 12.0 μmol, and the mixture was polymerized at 65° C. for 30 minutes.

Then, 0.94 mmol of an antioxidant was added in the state of an ethanol solution, and the mixture was stirred for 2 minutes, then ethanol was added to the obtained polymerization liquid to recover a polybutadiene rubber. Next, the recovered polybutadiene rubber was vacuum dried at 100° C. for 1 hour. Table 1 shows the physical properties of the obtained polybutadiene rubber.

Using the obtained polybutadiene rubber, the abrasion resistance and the low loss property were evaluated in the same manner as in Example 1. The evaluation results are shown in Table 1.

As described above, it has been found that the present invention can provide a polybutadiene rubber having high wear resistance and low loss and a rubber composition using the same.

Since the polybutadiene rubber according to the present invention has high wear resistance and low loss, it can be compounded into a rubber composition to include tires, anti-vibration rubbers, belts, hoses, seismic isolation rubbers, rubber crawlers and footwear. It can be used for members and the like.

Claims (5)

In the polystyrene-reduced molecular weight distribution curve by GPC, the peak top molecular weight (MW _p ) is 3.60×10 ⁵ or more, and the area ratio (R is in the range of 2.70×10 ^{6 to} 1.10×10 ⁷⁾ (R _A method for producing a polybutadiene rubber, wherein _a ) is 2.0% or more,
Mixing (C) an organometallic compound of Group I to III elements with (D) water in the presence of 1,3-butadiene;
By adding (A) a cobalt compound and (B) a non-coordinating anion and an ionic compound of a cation at the same time or at intervals of less than 3 minutes, the 1,3-butadiene is polymerized to give 1,4 -A step of obtaining polybutadiene,
And a step of reacting the 1,4-polybutadiene with an organic halogen compound. The ratio (T _cp /ML) of the 5 wt% toluene solution viscosity (T _cp ) and the Mooney viscosity (ML _{1+4,100° C.} ) of the 1,4-polybutadiene is 4.0 or more. Method for producing polybutadiene rubber. In the polystyrene-reduced molecular weight distribution curve by GPC, the peak top molecular weight (MW _p ) is 3.60×10 ⁵ or more, and the area ratio (R is in the range of 2.70×10 ^{6 to} 1.10×10 ⁷⁾ (R Polybutadiene rubber having _a ) of 2.0% or more. A rubber composition comprising the polybutadiene rubber according to claim 3 . A tire using the rubber composition according to claim 4.