JPS6230104A - Novel conjugated diene polymer, production and composition thereof - Google Patents

Abstract

PURPOSE:To obtain in high productivity a conjugated diene polymer containing a novel functional group at the end of a polymer chain, useful especially as a rubber composition for tire tread, by reacting a conjugated diene polymer having a bonded Li atom with a specific urea derivative. CONSTITUTION:One or more conjugated dienes (e.g., 1,3-butadiene, isoprene, etc.,) or the conjugated diene and a vinyl aromatic compound (e.g., styrene, etc.,) are polymerized in a hydrocarbon solvent by the use of an organolithium compound (e.g., n-propyllithium, etc.,) as a polymerization initiator to give a polymer having a bonded Li atom, which is reacted with a urea derivative (e.g., 1,3-diethyl-2-imidazolidinone, etc.,) shown by the formula I (R1 and R2 are 1-4C alkyl or alkoxyalkyl; Y is O or S; n is 2-4) at 70-115 deg.C to give a novel polymer having 10-150 Mooney viscosity (ML1+4, 100 deg.C), containing an atomic group shown by the formula II at the end of polymer chain. EFFECT:Having extremely improved balance of wet skid resistance, impact resilience and wear resistance.

Description

Detailed Description of the Invention [Industrial Field of Application J The present invention is directed to a novel functional group having a novel functional group at the end of a polymer chain formed by reacting a conjugated diene polymer bonding a lithium atom with a specific urea derivative. The present invention relates to a conjugated diene polymer, a method for producing the same, and a composition thereof.

[Prior Art] Conjugated diene polymers such as random styrene-butadiene copolymers and polybutadiene have traditionally been widely used as rubber for tires, but due to recent social demands for resource and energy conservation, With the demand for lower fuel consumption for automobiles, the demand for improved safety during driving, and the demand for improved durability, rubber for tires is required to have high rebound resilience to improve fuel efficiency, and high wettability to improve driving safety. Excellent abrasion resistance is required to improve skid resistance and durability.

However, the relationship between rebound resilience and wet skid resistance is contradictory, and the relationship between abrasion resistance and wet skid resistance is also contradictory, and various methods are used to balance these contradictory properties. A method is proposed. For example, a method of blending a styrene-butadiene copolymer with polybutadiene such as high-cis polybutadiene and low-cis polybutadiene, and a method of controlling the styrene distribution in the styrene-butadiene copolymer chain (JP-A-5
No. 2i-143209, JP-A-57-165445,
JP-A-57-200413), method for specifying styrene content and vinyl content of styrene-butadiene copolymer (JP-A-54-82248, JP-A-57-55912)
No.), and as a method of improving only the impact resilience, a method of introducing an aziridinyl group at the end of the polymer chain (Japanese Patent Publication No. 39-9
No. 2).

[Problems to be Solved by the Invention] However, although these methods have shown some improvement, they have not yet satisfied these contradictory characteristics to a high level.

The present invention was made in view of the above points, and provides a novel conjugated diene polymer with a significantly improved balance between wet skid resistance, impact resilience, and abrasion resistance, a method for producing the same, and a rubber composition thereof. The purpose is to provide.

[Means and effects for solving the problems] The present invention has the following features:
As a result of extensive research into conjugated diene polymers with functional groups bonded to their polymer chains and their compositions, we discovered that they were obtained by reacting an active polymer with lithium terminals and a specific urea derivative with a cyclic structure. It was discovered that a conjugated diene copolymer with a novel functional group at the end of the polymer chain has an outstanding balance of wet skid resistance, impact resilience, and abrasion resistance, and also has good tensile strength. It is something.

That is, the present invention provides a polymer that combines lithium atoms obtained by polymerizing at least one conjugated diene or a conjugated diene and a vinyl aromatic compound using an organolithium compound as a polymerization initiator in a hydrocarbon solvent. General formula (wherein, R1 and R2 each independently represent a C, -C, alkyl group, or an alkoxyalkyl group, Y is an oxygen atom,
or a sulfur atom, and 0 represents an integer from 2 to 4).
-C-N (.R2). It is a conjugated diene polymer having an atomic group of N-HYR2R1, and the Mooney viscosity (ML+-4,100°C) of the polymer is 1O
A method of obtaining the specific conjugated diene polymer by reacting a conjugated diene polymer having a molecular weight of 150 to 150, a polymer bonding a lithium atom, and a urea derivative represented by the above general formula at 70 to 115°C, and The present invention relates to a rubber composition containing at least 30% by weight of the polymer in the center of the rubber component.

The conjugated diene polymer of the present invention and the rubber composition using the polymer as a raw material rubber exhibit excellent properties and are used in various rubber applications, and are useful as tire tread applications.

The present invention will be explained in detail below.

The urea compound used in the present invention has a general formula (in the formula,
R] and R2 each independently represent an alkyl group of 01 to C4 or an alkoxyalkyl group, and Y represents an oxygen atom or a sulfur atom. represents an integer from 2 to 4).

This has extremely important meaning in achieving the present invention. Normally, in a stoichiometric reaction between a urea compound having an acyclic structure and a conjugated diene polymer that binds a lithium atom, the bond between the carbonyl group and the amine 7 group is broken, a coupling reaction occurs, and the conjugated diene polymer It is not possible to effectively introduce functional groups into On the other hand, in the stoichiometric reaction of the urea compound having a cyclic structure used in the present invention and the conjugated diene polymer that bonds lithium atoms in a hydrocarbon solvent, no coupling reaction occurs and the conjugated diene polymer Functional groups can be reliably introduced into the coalescence.

Furthermore, when this reaction is carried out at high temperatures, the reaction product undergoes hydrolysis and then undergoes a ring-opening reaction, resulting in having a secondary amine group exhibiting strong basicity at the end of the polymer chain. The above reaction is shown below (in the formula, P represents a polymer chain).

On the other hand, the reaction of cyclic urea derivatives and lithium-containing polymers at low temperatures is disclosed in JP-A No. 0-137913, in which no secondary amine groups are formed and the functional group structure is -G -N is indicated.

H When a conjugated diene polymer having 7 secondary amide groups at the end of the polymer chain is kneaded with carbon black, process oil, etc., its vulcanizate exhibits excellent impact resilience and abrasion resistance.

The analysis of the secondary amine group introduced at the end of this polymer chain is F
T-130-NMR, FT-IH-NMR, FTIR,
GPC: etc., but analysis by GPC is easiest.

Mooney viscosity (ML+
-4, 100℃) is 10 to 150, preferably 30 to 1
20, particularly preferably 40-65. If the Mooney viscosity is less than 10, the effect of improving impact resilience and abrasion resistance is not sufficient. If the Mooney viscosity exceeds 150, problems remain in the calendering processability and extrusion processability of the blend.

The conjugated diene polymer of the present invention is 1,3-butadiene, isoprene, 2,3-dimethyl-1,3-butadiene, 1
, 3-pentadiene, 3-methyl-1,3-pentadiene, 1,3-heptadiene, 1,3-hexadiene, etc., or a copolymer of conjugated dienes, or a conjugated diene and a vinyl aromatic It is a copolymer with a group compound such as styrene, α-methylstyrene, p-methylstyrene, p-methoxystyrene, 2-vinylnaphthalene, divinylbenzene, etc. Preferred conjugated diene polymers include polybutadiene, polyisoprene, and styrene-butadiene copolymers.

In the conjugated diene polymer of the present invention, the conjugated diene moiety has a 1.2 vinyl content of 10 to 65%, preferably 15 to 60%. If the 1,2 vinyl content exceeds 65%, the tensile strength, impact resilience, and abrasion resistance will decrease, which is undesirable/undesirable. On the other hand, 1.
If the 2-vinyl content is less than 10%, wet skid resistance decreases, which is undesirable.

Furthermore, regarding the distribution of 1- and 2-vinyl groups in a conjugated diene polymer chain, even if the distribution is uniform in the polymer chain, it may gradually decrease along the polymer chain as shown in Japanese Patent Publication No. 48-875. It may be something that changes cyclically, or even distributed like a block (USP-330184
0), in short, it is best to decide depending on the purpose of use.

Further, there are no particular limitations on the content of the vinyl aromatic compound in the copolymer of the conjugated diene and the vinyl aromatic compound, or the chain distribution of the vinyl aromatic compound in the copolymer chain.

For example, in the case of the commonly used styrene-butadiene copolymer, the styrene content is 5 to 50% for tire rubber.
45% by weight is the standard, commercially available rubbers for special purposes have a content of 45 to 85% by weight, and high styrene rubber used as bottom circumferential rubber generally has a content of 60 to 65% by weight. On the other hand, the chain distribution of styrene (decomposed product obtained by ozone cleavage of all the double bonds of butadiene units) was analyzed by gel permeation chromatography (GPC).
Proceedings of the Society of Polymer Science, Vol. 29, No. 9, p. 2055) are not particularly limited, but from the perspective of impact resilience and abrasion resistance,
It is desirable that the styrene single chain having one styrene unit is 40% by weight or more of the styrene content, and the styrene long chain having 8 or more styrene units is 5% by weight or less of the styrene content. However, when the styrene long chains are increased to 5% by weight or more of the styrene content, the extrusion surface and die swell during extrusion processing are improved, and the hardness of the vulcanizate is further improved. In any case, the styrene content of the styrene-butadiene copolymer or the chain distribution of styrene units in the copolymer chain may be determined depending on the intended use.

Regarding the styrene composition distribution in the copolymer chain, it may be uniformly distributed in the copolymer chain, or it may be non-uniformly distributed in the copolymer chain (Japanese Patent Application No. 80-4108). In short, it should be determined depending on the purpose of use.

Processability of the conjugated diene polymer of the present invention changes greatly by changing the molecular weight distribution.

The relationship between molecular weight distribution and processability is well known, and in the present invention, the molecular weight distribution (Mw) expressed as the ratio of weight average molecular weight (Mw) to number average molecular weight (MN) is known.
/MN) is not particularly limited, but in consideration of the balance between physical properties and workability, it is preferably 1.2 to 3.5. Further, the shape of the molecular weight distribution may be monomodal, bimodal or more polymodal.

The conjugated diene polymer of the present invention combines lithium atoms obtained by polymerization of a conjugated diene in a hydrocarbon solvent using an organolithium compound as a polymerization initiator, or by copolymerization of a conjugated diene and a vinyl aromatic compound. The conjugated diene polymer has the general formula I It can be obtained by adding a predetermined amount of a urea derivative represented by (representing an integer) and, after the reaction is complete, adding a proton donor such as alcohol or water to the reaction system.

The polymerization temperature of the conjugated diene polymer in the present invention needs to reach a maximum polymerization temperature of 90 to 130°C in either continuous polymerization or batch polymerization.

If the maximum polymerization temperature exceeds 130°C, the living anionic property will be impaired, which is not preferable. If the maximum polymerization temperature does not reach 90°C, the living anionic property will not be impaired, but productivity will decrease, which is not preferable.

In the present invention, the reaction between the conjugated diene polymer that binds lithium atoms and the urea derivative is carried out for a reaction time of 1 second to IO minutes and a reaction temperature of 70 to 115°C, preferably 85 to 100°C.
Performed at °C. Conventionally, the reaction between a polymer that binds lithium atoms and a polar compound requires a low temperature, but in the present invention, it is possible to open the ring of the urea derivative and introduce a new functional group to the end of the polymer chain at a high temperature. This was made possible through a reaction. If the reaction temperature exceeds 115°0, the reactivity between the urea derivative and the polymer bonding the lithium atoms decreases, which is not preferable. On the other hand, if the reaction temperature is less than 70°C, the exfoliating anionic property is not impaired, but the viscosity of the solution increases and the reactivity with the urea derivative decreases, which is not preferable.

Furthermore, since the reaction between the polymer that binds lithium atoms and the urea derivative must be carried out immediately after the completion of polymerization, it is important from the standpoint of high productivity that the above reaction can be carried out at high temperatures. Therefore, the fact that the reaction between a polymer that binds a lithium atom and a urea derivative as in the present invention can be carried out at high temperatures without impairing the living anionic property means that the polymer has a novel functional group at the terminal end of the polymer chain. It is also industrially useful in that it can produce conjugated diene polymers with excellent properties with high productivity.

The organolithium compound used in the present invention includes n-
Monoorganolithium compounds such as propyllithium, inpropyllithium, n-butyllithium, 5ec-butyllithium, tert-butyllithium, dilithiomethane, 1.4-dilithiobutane, 1.4-dilithio-2-
These include polyfunctional organolithium compounds such as ethylcyclohexane, 1,2-dilithio-1,2-diphenylmethane, and 1,3.5-)lilithiobenzene. These may be used alone or in a mixture of two or more. Further, as the polyfunctional organolithium compound used in the present invention, there is also used one which can be substantially turned into a polyfunctional organolithium compound by reacting the above-mentioned monoorganolithium compound with another compound. For example, a reaction product of a monoorganolithium compound and a polyvinyl aromatic compound (#Publication No. 55-6652), a reaction product of a monoorganolithium compound and a conjugate, a diene, and/or a monovinyl aromatic compound, and then a polyvinyl aromatic compound Reaction products of compounds, or monoorganolithium compounds, conjugated dienes,
and/or a reaction product obtained by simultaneously reacting a monovinyl aromatic compound and the king of polyvinyl compounds (West German Patent No. 2003384, etc.).

The amount of these organic lithium compounds used is usually 0.1 to 10 mmol per 100 g of conjugated diene monomer.

As the hydrocarbon solvent used in the present invention, aliphatic, cycloaliphatic and aromatic hydrocarbons can be used. For example, hydrocarbon solvents include propane, isobutane, n
-hexane, isooctane, cyclopentane, cyclohexane, benzene, toluene, etc., and particularly preferred solvents are n-hexane, cyclohexane, and benzene.

These may be used alone or as a mixture of two or more.

In the present invention, in order to adjust the microstructure of the conjugated diene position in the polymer chain or the randomness in the copolymer chain of the conjugated diene and the vinyl aromatic compound, tetrahydrofuran derivatives and tertiary amines are used. Polar compounds of the same class can be used. For example, tetrahydrofuran, α-methoxymethyltetrahydrofuran, α-methyltetrahydrofuran, triethylamine, N, N, N', N'-tetramethylpropanediamine, N, N, N', N'-
Tetramethylethylenediamine, N, N, N', N'-
Tetraethylethylenediamine and the like. These compounds may be used alone or as a mixture of two or more. It is also possible to use polar compounds such as diethylene glycol dimethyl ether (diglyme), diethylene glycol diethyl ether, etc. to adjust the microstructure of the conjugated diene units in the polymer chain.
When these polar compounds are used in the polymerization of a conjugated diene using an organolithium compound and a polymerization initiator, side reactions such as termination reactions and chain transfer reactions occur when the polymerization system is at a high temperature.
It is not possible to obtain polymers with high molecular weight. However, polar compounds such as tetrahydrofuran derivatives used in the present invention do not cause side reactions with the conjugated diene polymer that binds lithium atoms even at high temperatures, and maintain high productivity of the conjugated diene polymer. In this way, a polymer with a high molecular weight can be supplied. The amount of the polar compound used in the present invention is 0 to 200 mol, preferably 0.1 to 100 mol, per 1 mol of the organic lithium compound.

The urea derivative used in the present invention has the general formula (wherein R1 and R2 each independently represent an alkyl group of 01 to C4 or an alkoxyalkyl group, Y represents an oxygen atom or a sulfur atom, and 2 to 4 (representing an integer of
-imidazolidinone, 1,3-dipropyl-2-imidazolidinone, l-methyl-3-ethyl-2-imidazolidinone, 1-methyl-3-propyl-2-imidazolidinone, 1-methyl-3 -Butyl-2-imidazolidinone, 1-methyl-3-(2-methoxyethyl)-2-imidazolidinone, 1-methyl-3-(2-ethoxyethyl)-2-imidazolidinone, 1,3-di- (2-ethoxyethyl)-2-imidazolidinone, 1,3-dimethylnithylenethiourea, N,N'-diethylpropyleneurea, N-methyl-N'-ethylpropyleneurea,
1,3-dimethyl-3,4,5,8-tetrahydro-2
Examples include (+H)-pyrimidinone.

The amount of the urea derivative used in the present invention is usually 0.25 to 2.0 mol, preferably 0.4 to 1.5 mol, particularly preferably 0.25 to 2.0 mol, and particularly preferably is 1.0 mol.

In the present invention, it is necessary that 25% by weight or more, preferably 40% by weight or more of all polymer molecules be modified with a specific urea derivative.

Further, the conjugated diene polymer modified with a functional group used in the present invention may partially have a branched structure. Such a branched structure is introduced to improve low-temperature flow and processability of the polymer. In order to create a branched structure, it is possible to copolymerize a small amount of a monomer with more than two functionalities, such as divinylbenzene, or to add a part of the active end to a monomer with more than trifunctionality, such as silicon tetrachloride or tin tetrachloride. A method of reacting with a halogen compound, polyepoxy compound, polyester, etc. is adopted. These branched structures are
It is desirable to introduce the modified conjugated diene polymer within a range that does not lose its characteristics.

There are no particular limitations on the method of adding these urea derivatives, but in the case of a conjugated diene monomer (co)polymerization reaction, the following method is preferred.

For example, one method is to add a urea derivative after the (co)polymerization of a conjugated diene monomer, or to add a urea derivative and then add a coupling agent, or to add a coupling agent. , then add a urea derivative, or add butadiene and then add a urea derivative. Another method is to add a urea derivative in an amount that does not stop the (co)polymerization during the (co)polymerization of the conjugated diene monomer, and then add a campliner agent after the (co)polymerization path '7'. , or a method in which a urea derivative is added and then an organic lithium compound is added. In short, the method of adding the urea derivative should be determined depending on the purpose of use.

The polymerization method in the present F-man may be either a batch polymerization method or a continuous polymerization method.

After completion of the specified reaction, 2,6-tert-butyl-p-
After adding an antioxidant such as cresol, the resulting polymer is subjected to conventional post-treatments such as separation, washing, and drying to obtain the desired polymer.

The conjugated diene polymer of the present invention may be used as an oil-extended rubber by mixing it with a process oil in a solution state and removing the solvent after mixing.

The conjugated diene polymer of the present invention can be used alone or in a blend with natural rubber or other synthetic rubber such as polybutadiene, polyisoprene, emulsion polymerized styrene-butadiene copolymer, and the like. When used in a blend with natural rubber or other synthetic rubber, at least 30% by weight of the raw material rubber is required to exhibit the excellent properties of the present invention.
needs to be the conjugated diene polymer of the present invention.

Further, the conjugated diene polymer of the present invention is blended with known compounding agents such as carbon black, process oil, etc., mixed and vulcanized, and then used as a product, such as tire applications such as tire treads, carcass, and sidewalls. or extruded products,
It can be used for automobile window frames, industrial products, vibration and soundproofing applications, etc., and because it has excellent rebound resilience and abrasion resistance, it can be particularly used as a red for fuel-efficient tires.

[Examples] The present invention will be explained below with reference to Examples, but these Examples do not limit the present invention.

Note that measurements of various characteristics were carried out using the following methods.

Mooney viscosity is 1 using the L rotor in the usual way.
Measured at 00°C. The bonded styrene was calculated from the absorption based on the phenyl group at 2[(2 nm) by ultraviolet absorption spectroscopy. The Miku b structure of the butadiene moiety was calculated by the Hampton method using an infrared spectrophotometer.

The secondary amine group at the chain end of the conjugated diene polymer modified with a urea derivative with a cyclic structure is GP-contained using a Sosilica fine particle filler.
C confirmed and quantified using the C method GPC: 204 compact type manufactured by Water Co., Ltd. The column was a combination of Solpax PSM 100O3 (silica fine particle packing material) manufactured by DuPont and Solpax PSM 60S (silica fine particle packing material) manufactured by DuPont. I used something. The measurement was performed using tetrahydrofuran as a mobile phase at a flow rate of 0.7 mρ/min. Sample injection volume was 0.07mp, sample concentration was 1
．． 0mg/mj? Met. ]. A polymer having a secondary amine group bonded to the end of the polymer chain is preferentially retained on an acidic adsorbent such as silica, and is not separated within a normal separation time. However, after reacting the polymer with phenyl isocyanate for 3 minutes at room temperature to change the functional group structure at the end of the polymer chain,
When the polymer is analyzed by GPC in the same manner as above, an elution peak appears at the separation time of the polymer before being modified with the urea derivative having a cyclic structure. Therefore, the proportion of polymer chains to which secondary amine groups are bonded to the total polymer chain was calculated from the GPC area change before and after reacting the polymer with phenyl isocyanate (the calculation formula is shown below: F: Proportion of polymer chains bonded with 7 secondary amide groups in the total polymer chain So: Peak area of the polymer modified with a urea derivative before reacting with phenyl isocyanate S: The above modified polymer and phenyl isocyanate The peak area of the reaction product The hardness, tensile strength, 300% modulus, and elongation of the vulcanizate were measured according to JIS K 1330+.The repulsion properties were measured using a Dunlop trypsometer at a test temperature of 70
Measured at °C. Abrasion resistance was measured using a Pico abrasion tester. Wet skint resistance was measured using a device manufactured by the British Road Research Institute.

Examples 1 to 5, Comparative Examples 1 to 3 In a nitrogen atmosphere, 4.8 kg of cyclohexane, 15 g of tetrahydrofuran, and 750 g of 1,3-butadiene were charged into a stainless steel polymerization vessel with an internal volume of about 10 cm and equipped with a stirrer. While stirring the mixture vigorously, the temperature of the mixture was adjusted to about 70°C. Next, 0.45 g of n-butyllithium was added to initiate polymerization. The polymerization temperature reached the maximum temperature (approximately 85°C) and the polymerization was completed (
After polymerization time (12 minutes), 0.72 g of 1,3-dimethyl-2-imidazolidinone was added, and the reaction was carried out at that temperature for about 10 minutes. To the thus obtained polymer solution, 3.8 g of 2,8-di-tert-butyl-p-cresol was added as a stabilizer, and the solvent was removed by heating to obtain a polymer.

However, in Example 3, 15 g of tetrahydrofuran was mixed with N, N
, N', N'-tetramethylethylenediamine 0.25
g, and further, in Examples 2 to 5 and Comparative Examples 1 to 3, 1
, 3-dimethyl-2-imidazolidinone (0.72 g) was changed as follows, and polymerization was carried out. In Example 2, 1,3
- 0.90 g of diethyl-2-imidazolidinone, 1.0 g of 1-methyl-3-n-propyl-2-imidazolidinone in Example 3, N,N'-diethylpropylene urea 1 in Example 4 .1 g of N-methyl-N'-ethylpropylene urea in Example 5, and 0.54 g of 2-imidazolitone (ethylene urea) in Comparative Example 1.
g, in Comparative Example 2 it was changed to 0.73 g of tetramethylurea, and in Comparative Example 3 it was changed to 0.25 g of methanol. The basic properties of the polymer thus obtained are shown in Table 1. The molecular weight distribution curves of the polymers of Example 1 and Comparative Example 20 are shown in FIGS. 1 and 2, respectively. These polymers were kneaded and mixed in a small pressure kneader according to the formulation shown in Table 2, and the resulting unvulcanized rubber composition was vulcanized at 145°C and evaluated for physical properties. The measurement results are shown in Table-1.

As can be seen from Table 1, Examples 1 to 5 have an excellent balance of impact resilience, abrasion resistance, and wet skid resistance. Further, although Comparative Example 2 shows characteristics that are slightly improved compared to Comparative Example 1, the improvement effect is still insufficient.

Table 2 1) N-Cyclohexyl-2-benzothiazylsulfenamide 2) High-temperature reaction product of diphenylamine and acetone Example 6, Comparative Example 4 Polymerization vessel similar to that used in Example 1 under nitrogen atmosphere 4.8 kg of cyclohexane, 21 g of tetrahydrofuran
, 1,3-butadiene 577.5g, styrene 172
．． 5 g was charged, and the temperature of the mixture in the polymerization vessel was adjusted to about 71°C while stirring the mixture vigorously. Next, 0.53 g of n-butyllithium was added to start copolymerization. After the polymerization temperature reached the maximum temperature (92°C) and the copolymerization was completed (polymerization time 12 minutes), l-methyl-3
0.95 g of -ethyl-2-imidazolidinone was added and reacted at that temperature for about 10 minutes. 2,6-sheet tart- as a stabilizer was added to the polymer solution thus obtained.
3.8 g of butyl-p-cresol was added and the solvent was removed by heating to obtain a copolymer. However, in Comparative Example 4, 0.95 g of 1-methyl-3-ethyl-2-imidazolidinone was changed to 0.25 g of methanol, and the other polymerization conditions were the same as in Example 3 to perform copolymerization. The basic properties of the copolymer thus obtained are shown in Table 4. These copolymers were kneaded and mixed in a small pressure kneader according to the formulation shown in Table 3, and the resulting unvulcanized rubber compositions were vulcanized at 145°C and evaluated for their physical properties. The measurement results are shown in Table-4.

Table 3 Table 4 Proportion of polymer chains Example 7, Comparative Example 5 Two stainless steel polymerization vessels each having an internal volume of 10 cm and equipped with a stirrer were connected in series, and the first polymerization vessel was heated to 100°C. About 52 g/hr of n-butyl lithium, 11.8 g/hr of ethylene glycol dibutyl ether, 0.45 kg/hr of styrene, 1.3-butadiene were added from the inlet at the bottom of the polymerization reactor. ．．
Hexane was introduced continuously at an introduction rate of 35 kg/hr, 8 kg/hr and 7.2 kg/hr, and copolymerization was carried out in the first polymerization vessel. The polymer solution discharged from the outlet at the top of the first polymerization vessel is further continuously introduced into the bottom of the second polymerization vessel.
3-dimethyl-2-imidazolidinone 1.73g/hr
were added continuously to react. After reaction path γ, 2 groups l'
2,6-tert~butyl-p-cresol is added to the copolymer solution discharged from the outlet at the top of the polymerization vessel at a concentration of 0.5 g per 100 g of copolymer, and the solvent is heated. It was removed to obtain a copolymer. However, comparative example 4
A copolymer was obtained in the same manner as in Example 7 except that 1,3-dimethylimidazolidinone was not added. The basic properties of the copolymer thus obtained are shown in Table 5.

These copolymers were kneaded and mixed in a small pressure kneader according to the formulation shown in Table 3, and the resulting unvulcanized rubber compositions were vulcanized at 145°C and evaluated for their physical properties. 11+11
The results are shown in Table 5.

Table 5 1) F is the proportion of polymer chains to which secondary amine groups are bonded to the total polymer chain [Effects of the invention] The conjugated diene polymer according to the present invention This conjugated diene polymer and the rubber composition containing the polymer have high impact resilience and wet skid resistance. It has an excellent balance of wear resistance and abrasion resistance, and can be used in many tire applications such as tire treads, carcass, and sidewalls, as well as extruded products, automobile window frames, and industrial products. According to the method, the above-mentioned conjugated diene polymer can be produced with high productivity, and its industrial significance is great.

[Brief explanation of the drawing]

Figures 1 and 2 show the molecular weight distribution of the polymer analyzed by GpC. In each figure, the vertical axis shows relative concentration, and the horizontal axis shows minute-'f-amount. Figure 1 shows the molecular weight distribution of each polymer of Example 1, and Figure 2 shows the molecular weight distribution of each polymer of Comparative Example 2. The solid line is the molecular weight distribution curve of the reaction product of the polymer modified with a urea derivative and phenyl isocyanate. The dotted line is the molecular weight distribution curve of the polymer modified with the urea derivative before reacting with phenyl isocyanate.

Claims (3)

[Claims] (1) A polymer bonding lithium atoms obtained by polymerizing at least one conjugated diene, or a conjugated diene and a vinyl aromatic compound using an organolithium compound as a polymerization initiator in a hydrocarbon solvent, and the general formula ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼ (In the formula, R_1 and R_2 are each independently an alkyl group or an alkoxyalkyl group of C_1 to C_4, Y is an oxygen atom or a sulfur atom, and n is an integer from 2 to 4. It is a conjugated diene-based polymer that has an atomic group ▲ ▲ mathematical formula, chemical formula, table, etc. at the end of the chain of a polymer obtained by reacting a urea derivative shown by , 100℃)
is 10 to 150. (2) A polymer bonding lithium atoms obtained by polymerizing at least one conjugated diene, or a conjugated diene and a vinyl aromatic compound using an organolithium compound as a polymerization initiator in a hydrocarbon solvent, and the general formula ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼ (In the formula, R_1 and R_2 are each independently an alkyl group or an alkoxyalkyl group of C_1 to C_4, Y is an oxygen atom or a sulfur atom, and n is an integer from 2 to 4. The urea derivative represented by
A method for producing a conjugated diene polymer, characterized by obtaining a conjugated diene polymer having the following atomic group: (3) A polymer bonding lithium atoms obtained by polymerizing at least one conjugated diene, or a conjugated diene and a vinyl aromatic compound using an organolithium compound as a polymerization initiator in a hydrocarbon solvent, and the general formula ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼ (In the formula, R_1 and R_2 are each independently an alkyl group or an alkoxyalkyl group of C_1 to C_4, Y is an oxygen atom or a sulfur atom, and n is an integer from 2 to 4. It is a conjugated diene-based polymer that has an atomic group ▲ ▲ mathematical formula, chemical formula, table, etc. at the end of the chain of a polymer obtained by reacting a urea derivative shown by , 100℃)
A rubber composition characterized in that the rubber component contains at least 30% by weight of a conjugated diene-based polymer having a conjugated diene polymer of 10 to 150.