JPS63139902A - Preparation of modified diene polymer rubber - Google Patents

Abstract

PURPOSE:To obtain the titled rubber having an excellent impact resilience and a low JIS hardness at low temperatures, by reacting a conjugated diene polymer rubber, which is terminated with a specified alkali metal or to which is added an alkali metal, with a nitro compound. CONSTITUTION:An active conjugated diene polymer rubber (A) having an alkali metal bonded to the polymer terminal is obtained by polymerizing a conjugated diene monomer (a), or the monomer (a) and an aromatic vinyl monomer (b) in the presence of an alkali metal catalyst (c) in a hydrocarbon solvent, and a conjugated diene polymer rubber (B) containing an alkali metal added thereto is obtained by the addition reaction of a diene polymer rubber having conjugated diene units in a polymer chain in the presence of an alkali metal catalyst and, if necessary, a polar compound in a hydrocarbon solvent. The rubber (A) or (B) is reacted with 0.05-10mol [per mol of the ingredient (c)] of a nitro compound such as chloronitrobenzene, nitromethane, etc., at room temperature to 100 deg.C for several sec to several hr.

Description

Detailed Description of the Invention <Industrial Application Field> The present invention relates to a method for producing a modified diene polymer rubber, and more specifically, it relates to a method for producing a modified diene polymer rubber, and more specifically, a diene polymer having an active alkali metal end or a diene polymer rubber having an active alkali metal terminal or an alkali metal added thereto. The present invention relates to a method for producing a modified diene polymer rubber, which comprises reacting the conjugated diene polymer rubber and a nitro compound.

<Conventional technology> Conjugated diene polymer rubbers such as polybutadiene and butadiene-styrene copolymer rubber have traditionally been used as rubber for automobile tire treads, but in recent years there has been a demand for lower fuel consumption for automobiles and for use on snow and ice. Due to the demand for directional safety in automobile tires, rubber materials with low rolling resistance and high road grip on snow and ice have been desired as rubber for automobile tire treads.

The transfer resistance is correlated with the anti-f8 elasticity of the polymer, and the higher the anti-f8 elasticity, the lower the transfer resistance.

On the other hand, the road grip on snow and ice is
It is known that there is a correlation with IS hardness, and the lower the JIS hardness at low temperatures, the greater the road grip on snow and ice. However, these properties of existing rubber materials are unsatisfactory in practical terms.

<Problems to be Solved by the Invention> An object of the present invention is to provide a method for modifying diene polymer rubber that increases anti-ta elasticity and reduces JIs hardness at low temperatures.

<Means for Solving the Problems> As a result of extensive research by the present inventors in order to increase the anti-T8 elasticity of conjugated diene-based polymer rubber and to lower its JIS hardness at low temperatures, we found that alkali metal-containing diene-based The present invention was completed by discovering that the above object can be achieved by reacting a polymer with a specific compound and introducing a specific atomic group into the polymer.

That is, the present invention provides an active conjugated diene polymer having an alkali metal terminal obtained by polymerizing a conjugated diene monomer or a conjugated diene monomer and an aromatic vinyl monomer using an alkali metal catalyst in a hydrocarbon solvent. rubber or
Conjugated diene polymer rubber to which an alkali metal has been added is obtained by reacting a diene polymer rubber having conjugated diene units in the polymer chain with an alkali metal catalyst in a hydrocarbon solvent. The present invention relates to a method for producing a modified diene polymer rubber characterized by reacting compounds.

The alkali metal-containing diene polymer used in the present invention is obtained by polymerizing a diene monomer or this monomer and other monomers copolymerizable with it using an alkali metal-based catalyst. A diene polymer having a conjugated diene unit in the polymer chain, regardless of the polymerization method (e.g., solution polymerization, emulsion polymerization, etc.) It refers to a substance to which an alkali metal is added by the reaction.

Examples of the diene polymer rubber include 1,3-butadiene, isoprene, 1,3-pentadiene (piperylene), 2.
Polymer or copolymer rubber of conjugated diene monomers such as 3-dimethyl-1,3-butadiene and 1,3-hexadiene, or styrene, α-methylstyrene, which can be copolymerized with the conjugated diene monomer and the heptamer; Aromatic hinyl compounds such as vinyltoluene, vinylnaphthalene, divinylbenzene, trivinylbenzene, divinylnaphthalene, unsaturated nitriles such as acrylonitrile, (meth)
Examples include, but are not limited to, copolymer rubbers with esters of acrylic acid or vinylpyridine.

Specifically, polybutadiene rubber, polyisoprene rubber,
Examples include butadiene-isoprene copolymer rubber and butadiene-styrene copolymer rubber.

As mentioned above, diene polymer rubber in which an alkali metal is bonded to the end of the diene polymer rubber is obtained by polymerizing diene polymer rubber with an alkali metal-based catalyst. It is a living polymer with an alkali metal bonded to one end before polymerization is terminated. It is possible to use commonly used alkali metal-based catalysts, polymerization solvents, randomizers, microstructure modifiers of conjugated diene units, etc., and the method for producing the polymer is not particularly limited.

Diene polymer rubber, which is obtained by adding an alkali metal to diene polymer rubber, can be produced by solution polymerization using an alkali metal base catalyst, alkaline earth metal base catalyst, Ziegler catalyst, etc., or using a redox type catalyst, etc. Diene-based copolymer rubber (specifically polybutadiene) obtained by polymerizing or copolymerizing the above-mentioned conjugated diene monomer or a monomer copolymerizable therewith using a conventional polymerization method such as emulsion polymerization. Rubber, polyisoprene rubber, butadiene-styrene copolymer rubber, butadiene-isoprene copolymer rubber, polypentadiene rubber, butadiene-piperylene copolymer rubber, butadiene-propylene alternating copolymer rubber, etc.) It has an alkali metal added to it.

For addition of an alkali metal to a diene polymer rubber, a commonly practiced method is used. For example, a diene polymer rubber is added to a conventional alkali metal-based catalyst and an ether compound, an amine compound, or a phosphine compound in a hydrocarbon solvent. The addition reaction is carried out at a temperature of 30 to 100° C. for several tens of minutes to several tens of hours in the presence of a polar compound such as. The amount of the alkali metal-based catalyst used is usually in the range of 0.1 to 10 mmol per 100 g of the diene polymer rubber. Side reactions such as crosslinking and cutting of the polymer occur and do not contribute to improving the anti-total elasticity.

The amount of the polar compound is usually 0.1 to 10 mol, preferably 0.5 to 2 mol, per mol of the alkali metal-based catalyst.

Examples of alkali metal-based catalysts used in polymerization and addition reactions are as follows.

It is a complex with lithium, sodium, potassium, rubidium, cesium metal or a hydrocarbon compound or polar compound thereof.

Preference is given to lithium or sodium compounds having 2 to 2.0 carbon atoms.

For example, ethyllithium, n-propyllithium, 1s
o-propyllithium, n-butyllithium, 5ec-
Butyl lithium, t-octyl lithium, n-decyl lithium, phenyl lithium, 2-naphthyl lithium, 2
-butyl-phenyllithium, 4-phenyl-butyllithium, cyclohexyllithium, 4-cyclopentyllithium, 1,4-dilithio-butene-2, sodium naphthalene, sodium biphenyl, potassium te to form a hydrofuran complex, potassium jetoxyethane complex ,α
-Thorium salts of mer with methylstyrene.

The polymerization reaction and the alkali metal addition reaction are carried out in a hydrocarbon solvent or a solvent that does not destroy the alkali metal-based catalyst, such as tetrahydrofuran, hydropyran, dioxane, and the like.

Suitable hydrocarbon solvents are selected from aliphatic hydrocarbons, aromatic hydrocarbons, and alicyclic hydrocarbons, especially those having 2 to 2 carbon atoms.
Propane, n-butane, 1so-butane, n-pentane, 1so-pentane, n-hexane, cyclohexane, propene, l-butene, 1so-butene, and 2-butene, cis-2- Butene, 1-pentene, 2-pentene, 1-hexene, 2-hexene, benzene, toluene, xylene, ethylbenzene and the like are preferred. Further, two or more of these solvents can be used in combination.

Next, the compound to be reacted with the alkali metal-containing diene polymer rubber used in the present invention is a nitro compound having a nitro group in the molecule.

Specific examples of such nitro compounds are shown below.

(1) Aliphatic nitro compounds are mentioned.

Examples include, for example, nitromethane, nitroethane, 1-nitropropane, 2-nitropropane, 1-nitro-n-butane, 2-nitro-n-butane, 2-methyl-1-nitrobutane, 3-methyl -1-nitrobutane,
Mononitroparaffins such as 2-methyl-2-nitrobutane, 1-nitro-n-hexane, l-nitro-n-hebutane, l-nitro-n-octane, 2-nitro-n-octane, nitroethylene , 1-nitro-1-propene, 2-nitropropene, 3-nitro-1-propene, 1
- Nitro 1-7" ten, 2-nitro 2-butene, 1
-nitro 2-methyl-1-propene, 2-nitro 1
-7'tene, 2-nitro-1-pentene, 3-nitro-
1,3-pentadiene, 2-nitro-3-methyl-1,
3-butadiene, 1-nitro 4-methyl-1-pentene, 2-2) O-1-he-1y7.2-nitro-1-hebutene, l-nitro 1-octene, 1-nitro 2 ．．
4.4-) Mononitroolefins such as trimethyl-1-octene, chlornitromethane, bromnitromethane,
l-chloro-1-nitroethane, l-bromo-1-nitroethane, 2-chloro-1-nitroethane, 1-chloro-1-nitropropane, 1-bromo-1-nitropropane, 2-chloro- 1-nitropropane, 3-chloro-1
-nitropropane, l-chloro-2-nitropropane,
1-bromo-2-nitropropane, 2-chloro-2-nitropropane, 1,1-dichloro-1-nitroethane,
1.1-dibromo-1-nitroethane, 1. Monohalogen nitroparaffins such as l-dichloro-1-nitropropane, 1,1-dibromo-1-nitropropane, chloropicrin, bromopicrin, methyl-2-nitroethyl ether, ethyl-2-nitroethyl ether, 2-
Nitroethyl-n-propyl ether, 2-nitroethyl isopropyl ether, n-butyl-2-nitroethyl ether, methyl-2-nitroisopropyl ether, 3-methoxy-2-nitrobutane, methyl-2-nitropropyl Ether, mononitro ethers such as n-7'thyl-2-nitroisopropyl ether, ethyl nitro-tert-butyl ether, nitroacetone, 4
．． Mononitro ketones such as 4-dimethyl-5-nitro-2-pentanone and methyl-2=nitroethyl ketone, 1
．． 1-dinitroethane, 1. l-dinitropropane, 2
．． 2-dinitropropane, 1. l-dinitropenkune,
3.3-dinitropenkune, 1゜2-dinitroethane,
1,2-dinitropropane, 1,2-dinitrobutane,
2.3-dinitrobutane, 2-methyl-2,3-dinitropropane, 2.3-dimethyldinitrobutane, 1.3
-dinitropropane, 1,4-dinitrobutane, 1.5
-Dinitropenkune, 1,6-sinitrohexane, 2,
2-dimethyl-1,3-dinitropropane, tetrochlor-1,2-dinitroethane, tetrobrome-1,2-
Dinitroparaffins such as dinitroethane I! , 2.3-
Dinitroolefins such as dinitro-2-butene and 3,4-dinitro-3-hexene, trinitromethane, 1,
1.1-trinitroethane, chlortrinitromethane,
Examples include polynitro compounds such as bromotrinitromethane, iodotrinitromethane, tetronitromethane, and hexanitroethane.

(2) Examples include alicyclic nitro compounds.

Examples include, for example, nitrocyclopenkune, 1-
Methyl-1-nitrocyclopenkune, 1-methyl-2-
Nitrocyclopenkune, cyclopentyl nitromethane,
Nitrocyclohexane, l-methyl-1-nitrocyclohexane, 2-methyl-1-nitrocyclohexane, 4
-Methyl-1-nitrocyclohexane, 1,2-dimethyl-1-nitrocyclohexane, 1,3-dimethyl-1
-nitrocyclohexane, 1,4-dimethyl-1-nitrocyclohexane, 1-bromo-1-nitrocyclohexane, 1,2-dinitrocyclohexane, 1-ditromethylcyclohexane, 1-nitromethylcyclohexene, and the like.

(3) Aromatic nitro compounds.

Examples include nitrobenzene, 1-chloro-3-ditropenzoyl chloride, p-nitrophenyl-trifluoroacetate, 0-dinitrobenzene, m-dinitrobenzene, 1,5-difluor-2,4-dinitrobenzene, 3 .5-Dinitrobenzoyl chloride, p
-Dinitrobenzene, 1,2.3-1-dinitrobenzene, ■.

2.4-) dinitrobenzene, 1,3.5-trinitrobenzene, 1,2,3.5-te and nitrobenzene, 1
, 2,4.5-te and nitrobenzene, 0-fluoronitrobenzene, m-fluoronitrobenzene, p-fluoronitrobenzene, l-fluoro-2,4-dinitrobenzene, 0-chloronitrobenzene, m-chloronitrobenzene , p-chloronitrobenzene, l-chloro-
2,4-dinitrobenzene, l-chloro-2,6-dinitrobenzene, 1-chloro-3,4-dinitrobenzene, 1-chloro-2,4,6,-1-dinitrobenzene,
3,4-dichloronitrobenzene, 3.5-dichloronitrobenzene, 2.4-dichloronitrobenzene, 2.
5-'; Chlornitrobenzene, 4.5-dichloro-1,2-dinitrobenzene, 4.6-dichloro-1,
3-dinitrobenzene, 2.5-dichloro-1,3-dinitrobenzene, 2.4.51-dichloronitrobenzene, 2-chloro-4-nitrotoluene, 2-chloro-6-
Nitrotoluene, 4-chloro-2-nitrotoluene, 2
-chloro3, 4-dinitrotoluene, 2-chloro-3,
5-dinitrotoluene, 〇-bromnitrobenzene, m
-bromnitrobenzene, p-bromnitrobenzene,
■-Pro11-2,4-dinitrobenzene, 1-bromo-3,4-dinitrobenzene, 1-bromo-2,4,6
-trinitrobenzene, 2,3-dibromnitrobenzene, 3,4-dibromnitrobenzene, 2,4-dibromnitrobenzene, 2,6-dibromnitrobenzene,
4.6-dipromo-1.3-dinitrobenzene, 2.5
-dibromo-1,4-dinitrobenzene, 2.4.6-
Tribromnitrobenzene, 2-bromo-4-nitrotoluene, 2-bromo-5-nitrotoluene, 3-7'romo-2-nitrotoluene, 3-bromo-4-nitrotoluene, O-iodonitrobenzene , m-iodonitrobenzene, 1-iodo-2,4-dinitrobenzene, l-
Iodo-3,4-dinitrobenzene, 3.4.5-triiodonitrobenzene, 1-nitronaphthalene, 2-nitronaphthalene, dinitronaphthalenes, trinitronaphthalenes, nitronaphthalenes, nitromethylnaphthalenes , nitrophenylnaphthalenes, halonitronaphthalenes, halodinitronaphthalenes, 5-nitrote and phosphorus, 6-nitrote and phosphorus, 5.6-dinitrote and phosphorus, 5.7-dinitrote and phosphorus,5. 8-
dinitrote and phosphorus, 6.7-dinitrote and phosphorus, 3
-Nitro-1,2-naphthoquinone, 7-nitro-1,2
- naphthoquinone, 3-methyl-2-nitro-1,4-naphthoquinone, 4-chloro-3-nitro-1,2-naphthoquinone, 2,3-dichloro-5-nitro-1,4-naphthoquinone, nitroane Quinone, dimethyl p-nitrophthalate, 4,4'-dinitrodiphenyl, 4,4'-
Examples include dinitrodiphenylmethane and ethylbis(2,4-dinitrophenyl)acetate.

(4) Examples include heterocyclic nitro compounds.

Examples include 7-chloro-4-nitropenzofurazane, 2-chloro-5-nitropyridine, 2.4.5-trinitro-9-fluorene, 2°4.7-1-dinitro-9- Examples include fluorene and nitrocarbazole.

The amount of the nitro compound to be used is determined by the amount of the alkali metal-based catalyst used in the production of diene polymer rubber with an alkali metal bonded to the end, or the amount used when adding an alkali metal to the diene polymer rubber in a subsequent reaction. The amount is usually 0.05 to 10 mol, preferably 0.2 to 2 mol per mol of the alkali metal-based catalyst used.

The nitro compound and an active conjugated diene polymer rubber having an alkali metal end or an alkali metal.

Since the reaction with the added conjugated diene polymer rubber occurs quickly, the reaction temperature and reaction time can be selected over a wide range, but are generally room temperature to 100°C and a few seconds to several hours.

The reaction can be carried out by bringing the alkali metal-containing diene polymer rubber into contact with the nitro compound. For example, the diene polymer rubber is polymerized using an alkali metal-based catalyst, and the nitro compound is added to the polymer rubber solution. Preferred examples include a method in which a predetermined amount of the compound is added, and a method in which the nitro compound is subsequently added and reacted after completion of the alkali metal addition reaction in the diene polymer rubber solution, but the method is not limited to these methods. It's not something you can do.

The obtained modified diene polymer rubber has a nitro compound introduced at the molecular end or into the molecular chain.

After the reaction is completed, the modified diene polymer rubber can be coagulated using the same coagulation methods used in conventional solution polymerization rubber production, such as adding a coagulant from the reaction solution or steam coagulation, and there are no restrictions on the coagulation temperature. It has not been.

For drying the crumb separated from the reaction system, a band dryer, an extrusion type dryer, etc., which are commonly used in the production of synthetic rubber, can be used, and the drying temperature is not limited at all.

The modified diene polymer rubber thus obtained has improved impact resilience and JIS hardness at low temperatures compared to unmodified rubber, so it is particularly preferably used for automobile tires, but for other applications. It can also be used as raw material rubber for various industrial applications such as shoe soles, flooring materials, and anti-vibration rubber.

<Examples> The present invention will be specifically explained below with reference to Examples, but the present invention is not limited to these Examples.

Example 1 A stainless steel polymerization reactor with an internal volume of 101 liters was washed, dried, and replaced with dry nitrogen, and then 1,3-butadiene 1000
4300 g of n-hexane, 40 mmol of ethylene glycol diethyl ether, and 6.0 mmol of n7'chillithium (n-hexane solution) were added, and polymerization was carried out at 50° C. for 1 hour with stirring.

After the polymerization was completed, 3.0 mmol of p-chloronitrobenzene was added and the reaction was allowed to proceed for 30 minutes with stirring, followed by the addition of 10 milliliters of methanol and further stirring for 5 minutes.

The contents of the polymerization reactor were then removed and 5 g of 2.6-
After adding di-t-butyl-p-cresol (Sumilizer ■BHT manufactured by Sumima Kagaku Co., Ltd.) and evaporating most of the n-hexane, the mixture was dried under reduced pressure at 60° C. for 24 hours.

The Mooney viscosity, l, and amount of 2-bond units (by infrared spectroscopy) of the produced polymer rubber were measured.

The resulting polymer rubber had a Mooney viscosity of 77 and a vinyl content of 70%.

Comparative Example 1 A polymer was obtained in the same manner as in Example 1 except that p-chloronitrobenzene was not added.

The resulting polymer rubber had a Mooney viscosity of 23 and a vinyl content of 70%.

Comparative Example 2 Not adding p-chloronitrobenzene and n-
A polymer was obtained in the same manner as in Example 1 except that butyllithium was changed to 3.9 mmol.

The resulting polymer rubber had a Mooney viscosity of 77 and a vinyl content of 70%.

Example 2 A stainless steel polymerization reactor with an internal volume of 101 ml was washed, dried, and replaced with dry nitrogen, and then 100 ml of 1,3-butadiene was washed, dried, and replaced with dry nitrogen.
0 g, 4300 g of n-hexane, 40 mmol of ethylene glycol diethyl ether, and 5.0 mmol of n-butyllithium (n-hexane solution) were added, and polymerization was carried out at 50° C. for 1 hour with stirring.

After the polymerization was completed, 5.0 mmol of chloropicrin was added,
After reacting for 30 minutes with stirring, 10 milliliters of methanol was added and the mixture was further stirred for 5 minutes.

The contents of the polymerization reactor were then removed and 5 g of 2.6-
Di-t-butyl-p-cresol (Sumilizer'IB
After adding HT) to evaporate most of the n-hexane, the mixture was dried under reduced pressure at 60°C for 24 hours.

The Mooney viscosity and vinyl content M (by infrared spectroscopy) of the produced polymer rubber were measured.

The resulting polymer rubber had a Mooney viscosity of 84 and a vinyl content of 70%.

Comparative Example 3 A polymer was obtained in the same manner as in Example 1 except that chloropicrin was not added.

The resulting polymer rubber had a Mooney viscosity of 46 and a vinyl content of 70%.

Comparative Example 4 A polymer was obtained in the same manner as in Example 1, except that chloropicrin was not added and n-butyllithium was used at 3.8 mmol.

The resulting polymer rubber had a Mooney viscosity of 84 and a vinyl content of 70%.

Example 3 A stainless steel polymerization reactor with an internal volume of 101 liters was washed, dried, and replaced with dry nitrogen, and then 100 ml of 1,3-butadiene was washed, dried, and replaced with dry nitrogen.
0 g, n-hexane 4300 g, ethylene glycol diethyl ether 40 mmol, n-butyl lithium (
6.4 mmol of n-hexane solution) was added, and polymerization was carried out at 50° C. for 1 hour with stirring.

After the polymerization was completed, 3.2 mmol of dimethyl p-nitrophthalate was added, and the reaction was allowed to proceed for 30 minutes with stirring, followed by the addition of 10 ml of methanol and further stirring for 5 minutes.

The contents of the polymerization reactor were then removed and 5 g of 2.6-
Di-t-butyl-p-cresol (Sumilizer ■BH
After adding T) and evaporating most of the n-hexane,
It was dried under reduced pressure at 60°C for 24 hours.

The Mooney viscosity and vinyl content ff1 (by infrared spectroscopy) of the produced polymer rubber were measured.

The resulting polymer rubber had a Mooney viscosity of 56 and a vinyl content of 70%.

Comparative Example 5 A polymer was obtained in the same manner as in Example 3 except that dimethyl p-nitrophthalate was not added.

The resulting polymer rubber had a Mooney viscosity of 17 and a vinyl content of 70%.

Comparative Example 6 Not adding dimethyl p-nitrophthalate and n
A polymer was obtained in the same manner as in Example 3 except that -butyllithium was changed to 4.5 mmol.

The resulting polymer rubber had a Mooney viscosity of 56 and a vinyl content of 70%.

Example 4 A stainless steel polymerization reactor with an internal volume of 10β was washed, dried, and replaced with dry nitrogen, and then 1,3-butadiene 750
g, styrene 250 g, n-hexane 4300 g
, Te and 23 g of hydrofuran, n-butyllithium (
6.4 mmol of n-hexane solution) was added, and polymerization was carried out at 50° C. for 1 hour with stirring. After the polymerization was completed, 3.2 mmol of p-chloronitrobenzene was added, and 3.2 mmol of p-chloronitrobenzene was added under stirring.
After reacting for 0 minutes, 10 ml of methanol was added and stirred for an additional 5 minutes.

The contents of the polymerization reactor were then removed and 5 g of 2.6-
Di-t-butyl-p-cresol (Sumilizer @BH
After adding T) and evaporating most of the n-hexane,
It was dried under reduced pressure at 60°C for 24 hours.

Mooney viscosity, vinyl content (by infrared spectroscopy) and styrene content (by refractive index method) of the resulting polymer rubber
was measured.

The resulting polymer rubber had a Mooney viscosity of 77, a styrene content of 25%, and a vinyl content of 40%.

Comparative Example 7 A polymer was obtained in the same manner as in Example 4 except that p-chloronitrobenzene was not added.

The resulting polymer rubber had a Mooney viscosity of 23, a styrene content of 25%, and a vinyl content of 40%.

Comparative Example 8 Not adding p-chloronitrobenzene and n-
A polymer was obtained in the same manner as in Example 4 except that butyllithium was changed to 4.0 mmol.

The resulting polymer rubber had a Mooney viscosity of 77, a styrene content of 25%, and a vinyl content of 40%.

Example 5 A stainless steel polymerization reactor with an internal volume of 1 (l) was washed, dried, and replaced with dry nitrogen, and then 1,3-butadiene 750
g1 Styrene 250 g, n-hexane 4300 g
, Te and 40 mmol of hydrofuran and 5.2 mmol of n-butyllithium (n-hexane solution) were added, and polymerization was carried out at 50'C for 1 hour with stirring.

After the polymerization was completed, 5.2 mmol of chloropicrin was added and the reaction was allowed to proceed for 30 minutes with stirring, followed by the addition of 10 ml of methanol and further stirring for 5 minutes.

The contents of the polymerization reactor were then removed and 5 g of 2.6-
Di-t-butyl-p-cresol (Sumilizer @BH
After adding T) and evaporating most of the n-hexane,
It was dried under reduced pressure at 60°C for 24 hours.

Mooney viscosity, vinyl content (by infrared spectroscopy) and styrene content (by refractive index method) of the resulting polymer rubber
was measured.

The resulting polymer rubber had a Mooney viscosity of 84, a styrene content of 25%, and a vinyl content of 40%.

Comparative Example 9 A polymer was obtained in the same manner as in Example 5 except that chloropicrin was not added.

The resulting polymer rubber had a Mooney viscosity of 46, a styrene content of 25%, and a vinyl content of 40%.

Comparative Example 10 A polymer was obtained in the same manner as in Example 5, except that chloropicrin was not added and n-butyllithium was used at 3.8 mmol.

The resulting polymer rubber had a Mooney viscosity of 84, a styrene content of 25%, and a vinyl content of 40%.

Example 6 A stainless steel polymerization reactor with an internal volume of 101 kg was washed, dried, and replaced with dry nitrogen, and then 750 g of 1,3-butadiene was added.
, 250 g of styrene, 4300 g of n-hexane
, Te and 23 g of hydrofuran, n-butyllithium (n
-Hexane solution) 7.2 mmol was added, and polymerization was carried out at 50° C. for 1 hour with stirring.

After the polymerization was completed, 3.6 mmol of dimethyl p-nitrophthalate was added, and the reaction was allowed to proceed for 30 minutes with stirring, followed by the addition of 10 ml of methanol and further stirring for 5 minutes.

After that, the contents of the polymerization reactor were taken out and 5 g of 2.6-di-t-butyl-p-cresol (Sumilizer@BH'
After adding T') and evaporating most of the n-hexane, the mixture was dried under reduced pressure at 60°C for 24 hours.

Mooney viscosity, vinyl content (by infrared spectroscopy) and styrene content (by refractive index method) of the resulting polymer rubber
was measured.

The resulting polymer rubber had a Mooney viscosity of 56, a styrene content of 25%, and a vinyl content of 40%.

Comparative Example 11 Example 6 except that dimethyl p-phthalate was not added.
The polymer was obtained in the same manner.

The resulting polymer rubber had a Mooney viscosity of 17, a styrene content of 25%, and a vinyl content of 40%.

Comparative Example 12 Not adding dimethyl p-nitrophthalate and n
A polymer was obtained in the same manner as in Example 6 except that -butyllithium was changed to 4.8 mmol.

The resulting polymer rubber had a Mooney viscosity of 56, a styrene content of 25%, and a vinyl content of 40%.

(Compounding/vulcanized rubber physical properties) The polymer rubbers produced in Examples 1 to 6 and Comparative Examples 1 to 12 were kneaded on a roll according to the compounding recipe in Table 1 to obtain a compounded rubber, which was heated at 160°C for 30 minutes. Press vulcanization was performed under the following conditions.

Anti-ta elasticity of vulcanized rubber
1 Table 1) Use N-339 2) Use aromatic oil with a pour point of 27°C *3) Measured at 60°C using N-cyclohexyl-2-benzothiazyl star. JIS hardness is JIS
Measured with K6301 at -20°C.

These results are shown in Table 2. From this result, the polymer of the present invention is obtained by the same method as the polymer of the present invention except that no nitro compound is added, and does not contain a nitro compound that has the same Mooney viscosity as the polymer of the present invention. Resilience is significantly higher than that of polymers, and JI at low temperatures is
It can be seen that the S hardness is extremely low.

Example 7 and Comparative Example 13 A stainless steel polymerization reactor with an internal volume of 10
500g (25% styrene content, 40% vinyl content),
4300 g of n-hexane was charged and dissolved with stirring.

Next, n-butyllithium (n-hexane solution) 6.4
mmol and te and methylethylenediamine6.4
mmol was added and reacted at 70°C for 1 hour.

Next, 3.2 mmol of p-chloronitrohenzene was added and the mixture was allowed to react for 30 minutes with stirring, followed by the addition of 10 milliliters of methanol and further stirring for 5 minutes.

The contents of the polymerization reactor were then removed and 5 g of 2.6-
Di-t-butyl-p-cresol (Sumilizer @BH
After adding T) and evaporating most of the n-hexane,
It was dried under reduced pressure at 60°C for 24 hours. The obtained polymer had a Mooney viscosity of 66.

Next, the polymer was blended in the same manner as in Example 1,
The physical properties of the vulcanized rubber were measured.

For comparison, the styrene-pucdiene copolymer (Mooney viscosity 51, styrene content 25%, vinyl content 40%) before modification was compounded in the same manner and the physical properties of the vulcanized rubber were measured. did.

These results are shown in Table 2.

<Effects of the Invention> As described above, according to the present invention, anti-18 elasticity is increased,
A method for modifying diene copolymer rubber that reduces JIS hardness at low temperatures can be provided.

Claims (1)

[Claims] An active conjugated diene polymer rubber having an alkali metal terminal obtained by polymerizing a conjugated diene monomer or a conjugated diene monomer and an aromatic vinyl monomer using an alkali metal catalyst in a hydrocarbon solvent, or
Conjugated diene polymer rubber to which an alkali metal has been added is obtained by reacting a diene polymer rubber having conjugated diene units in the polymer chain with an alkali metal catalyst in a hydrocarbon solvent. A method for producing a modified diene polymer rubber, characterized by reacting a compound.