JP2712612B2 - Method for producing conjugated diene polymer - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention provides a monomer having a conjugated diene as a main component,
Polymerization using a catalyst system containing (a) a barium compound, (b) an organoaluminum compound, (c) an organomagnesium compound, and (d) an alcohol-based compound provides wear resistance and mechanical properties (particularly high-temperature tensile strength). ) Excellent high content of trans-1,4 linkages and low content of 1,2 or 3,4
The present invention relates to a method for producing a conjugated diene-based polymer having a bond (hereinafter referred to as “vinyl bond”) with high activity.

[Conventional technology]

In recent years, as the performance of automobiles has become higher, there has been an increasing demand for rubber materials such as tires to be improved in workability, wear resistance, mechanical properties, and the like.

In order to satisfy these characteristics, high cis-1,4-polybutadiene obtained using a conventional Ziegler type catalyst, low cis-1,4-polybutadiene or styrene-butadiene obtained using a lithium-based catalyst are used. It was difficult with a copolymer, a polybutadiene or a styrene-butadiene copolymer obtained by emulsion polymerization.

On the other hand, besides the above-mentioned polymers, polybutadiene and styrene-butadiene copolymer having a high trans-1,4 bond content are known, but these polymers have various vulnerabilities such as unsatisfactory vulcanization properties or extremely difficult production methods. There is a problem,
Not practical.

As conventional polymerization catalysts having a high trans-1,4 bond content and capable of copolymerizing a conjugated diene and an aromatic vinyl compound, the following alkaline earth metal catalysts, especially barium catalysts, are known.

(I) A catalyst system containing a compound containing a barium-heteroatom bond and an organic metal as main components. (A) Japanese Patent Publication No. 52-48910 discloses that styrene is used as a polymerization catalyst with barium tertiary alkoxide and dibutylmagnesium. A copolymerization reaction of benzene and 1,3-butadiene is disclosed, but there is a problem in this reaction that the polymerization activity is low.

(B) In Japanese Patent Publication No. 56-45401, (Wherein, R's are the same or different, at least one R 'is a methyl group or a cyclohexyl group, and the remaining R's are selected from the group consisting of an alkyl group having 1 to 6 carbon atoms and a cyclohexyl group; : b molar ratio is about 97.5: 2.5-90:
10), a copolymerization reaction of styrene and 1,3-butadiene using a polymerization catalyst of a barium-based compound represented by the formula:
The introduction of groups is very complex and the trans 1,4
The bond content is less than about 80%, which is not practical.

(C) JP-B-52-30543 discloses a copolymerization reaction of styrene and 1,3-butadiene using an organic lithium, barium compound and an organic aluminum compound as a polymerization catalyst.

However, in order to make the trans 1,4 bond content relatively high, it is necessary to increase the proportion of the organoaluminum compound to be used, and at this time, the molecular weight of the obtained polymer decreases, or the copolymerizability of styrene also increases. There is a disadvantage that it decreases.

(D) On the other hand, Tsuruta et al. Describe the R (CH ₂ CH ₂ O) _n Li / n-BuLi system,
Alternatively, a copolymerization reaction of styrene and 1,3-butadiene using a (CH ₃ ) ₂ NCH ₂ CH ₂ OLi / n-BuLi-based catalyst has been reported [Industrial Chemistry, 72 , 994 (1969); J. .Macromol.Sci.Che
m., A4 , 885 (1970)].

Further, Japanese Patent Publication No. 57-34843 discloses a combination of the knowledge of Tsuruta et al. And that of Japanese Patent Publication No. 52-30543 with styrene in a barium compound / organoaluminum compound / organic lithium compound / lithium alkoxide catalyst. And 1,3-butadiene as well as 1,3-butadiene polymerization are disclosed.

(E) Japanese Patent Application Laid-Open No. 56-112916 discloses 1,3-butadiene polymerization using a barium compound / organic lithium / magnesium compound / organoaluminum compound catalyst, but has a problem that the molecular weight is difficult to increase. There is.

(Ii) Catalyst system containing barium art complex as the main component (f) Fujio et al. Reported that barium zinc tetrabutyl [BaZn (C
₄ H _{9) 4]} was Art complex (ate-complex), such as a polymerization catalyst [Japanese Chemical Journal, 440 (1972)], further ZMBaidako
va et al. in a hydrocarbon or electron donor solvent, Ba (Al
(C ₂ H ₅ ) ₄ ) ₂ and other ate complexes as polymerization catalysts (Polymer
Sci., USSR, 16 , 2630 (1974)], and reports on 1,3-butadiene-styrene copolymerization. The former has a low trans 1,4 bond content of about 70% or less, and the latter has a polymerization rate of Is slow, 50
There is a problem because the monomer conversion rate is very low at 75% at 100 ° C for 100 hours.

(G) Japanese Patent Publication No. 60-2323 discloses the aforementioned ZMBaidako
Similar to the method of va et al., 1,3-- using an organic barium aluminum compound (art complex) / electron donor catalyst
Although butadiene polymerization is disclosed, the polymerization activity is still low and is not suitable for practical use.

(H) JP-B-59-17724 discloses an organic lithium compound / organic barium aluminum compound (art complex)
Although 1,3-butadiene polymerization using a system catalyst is disclosed, the trans-1,4 bond content is as low as 80% or less, and the control of the trans-1,4 bond content is poor.

As described above, many conjugated diene-based polymers using a catalyst system containing a barium compound as a main component have been proposed, but the polymerization activity is low, or the trans 1,4 bond content is low, and the crystal melting point is controlled, or There are problems such as difficulty in controlling the molecular weight.

[Problems to be solved by the invention]

The present invention has been made in view of the above-mentioned conventional technical problems, and has a high trans-1,4 bond content, easy controllability, high polymerization activity, and easy control of molecular weight. An object of the present invention is to provide a method for producing a polymer.

[Means for solving the problem]

The present invention relates to (a) a barium compound (hereinafter referred to as “component (a)”), (b) an organoaluminum compound (hereinafter referred to as “(b) component”), and (c) an organomagnesium compound (hereinafter referred to as “(c) component). And (d) the general formula
A compound represented by HOR (wherein R represents an alkyl group having 4 to 20 carbon atoms or an aryl group having 6 to 20 carbon atoms, or a hydrocarbon residue having an oxygen atom and / or a nitrogen atom) (A) a catalyst composition containing (d) a component, and polymerizing a monomer having a conjugated diene as a main component in an inert organic solvent. It is.

Specific examples of the barium compound (a) used in the present invention include barium dimethoxide, barium diethoxide, barium diisopropoxide, and barium di-n.
-Butoxide, barium disec-butoxide, barium di-t-butoxide, barium di (1,1-dimethylpropoxide), barium di (1,2-dimethylpropoxide), barium di (1,1-dimethylbutoxide), barium di (1,1 -Dimethylpentoxide), barium di (2-ethylhexanoxide), barium di (1-methylheptoxide), barium diphenoxide, barium di (p-methylphenoxide), barium di (p-butylphenoxide), barium di (o- Methylphenoxide), barium di (p-octylphenoxide), barium di (p-nonylphenoxide), barium di (p-
Dodecylphenoxide), barium di (α-naphthoxide), barium di (β-naphthoxide), barium di (o-methoxyphenoxide), barium di (m-methoxyphenoxide), barium di (p-methoxyphenoxide), barium di (o-ethoxyphenoxide),
It is a dialkoxy barium compound such as barium di (4-methoxy-1-naphthoxide), and preferably barium di-t-butoxide, barium di (2-ethylhexanoxide), and barium di (p-nonylphenoxide).

Further, the barium compound as the component (a) includes an alkoxide group or a phenoxide group per barium atom.
A partial hydrolyzate in which 0.1 to 0.5 equivalents are substituted with hydroxy groups is also used.

As the organoaluminum compound as the component (b),
Specifically, trimethyl aluminum, triethyl aluminum, triisopropyl aluminum, tripropyl aluminum, tributyl aluminum, triisobutyl aluminum, pentyl diethyl aluminum, 2-
Methylpentyl-diethylaluminum, dicyclohexylethylaluminum, tripentylaluminum,
Trihexyl aluminum, trioctyl aluminum, tri (2-ethylhexyl) aluminum, tricyclohexyl aluminum, tricyclopentyl aluminum, tri (2,2,4-trimethylpentyl) aluminum, tridodecyl aluminum, tri (2-methylpentyl) aluminum, Examples thereof include diisobutylaluminum hydride, diethylaluminum hydride, dipropylaluminum hydride, propylaluminum dihydride, and isobutylaluminum dihydride. Of these, trimethylaluminum, triethylaluminum, and triisobutylaluminum are preferable because of their easy availability. As the component (b), one type can be used alone, or two or more types can be used in combination.

As the organomagnesium compound as the component (c),
Examples thereof include dialkylmagnesium compounds, diarylmagnesium compounds, and alkylmagnesium halides.Specifically, dimethylmagnesium, dipropylmagnesium, dibutylmagnesium, ethylbutylmagnesium, ethylhexylmagnesium, dihexylmagnesium, dioctylmagnesium, didecylmagnesium, didodecyl Magnesium, dicyclohexyl magnesium, dicyclopentyl magnesium, diphenyl magnesium, ditolyl magnesium, ethyl magnesium bromide, ethyl magnesium chloride, allyl magnesium bromide, propyl magnesium bromide, n-butyl magnesium chloride, phenyl magnesium bromide, phenyl magnesium iodide and the like.

These organomagnesium compounds as the component (c) can be used alone or as a mixture.

Examples of the alcohol compound as the component (d) include at least one compound selected from the group represented by the following general formulas (I) to (VIII).

(In the formula, R ^{1 to} R ³ are the same or different, and represent a hydrogen atom, an alkyl group having 1 to 20 carbon atoms or an aryl group having 6 to 20 carbon atoms, and n represents an integer of ^{1 to 3.} ) (Wherein, R ^{1 to} R ³ are the same as above, R ^{4 to} R ⁵ are the same as R ^{1 to} R ³ , and n is the same as above.) R ¹ _mN -[(CH ₂ ) _n -OH] _{3 -m} (III) (wherein, R ¹ and n are the same as above, and m represents an integer of 0 to 2.) (In the formula, R ⁶ is an alkylene group having 3 to 10 carbon atoms, and n is the same as described above.) (In the formula, R ⁷ and R ⁸ are an alkylene group having 2 to 5 carbon atoms, and n is the same as described above.) (In the formula, R ⁷ , R ⁸ and n are the same as described above.) (In the formula, R ⁷ , R ⁸ and n are the same as described above.) (In the formula, R ¹ , R ² and n are the same as described above.) Specific examples of the alcohol compound as the component (d) include t-butanol, sec-butanol, cyclohexanol, octanol, and 2-ethyl. Hexanol, p-cresol, m-cresol, nonylphenol, hexylphenol, tetrahydrofurfuryl alcohol, furfuryl alcohol, 3-methyl-tetrahydrofurfuryl alcohol, 4-ethyl-tetrahydrofurfuryl alcohol, oligomers of tetrahydrofurfuryl alcohol, ethylene Glycol monophenyl ether, ethylene glycol monobutyl ether, N, N
-Dimethylethanolamine, N, N-diethylethanolamine, N, N-dibutylethanolamine, N, N-diphenylethanolamine, N-methyldiethanolamine, N-ethyldiethanolamine, N-butyldiethanolamine, N-phenyldiethanolamine, N- , N
-Dimethylpropanolamine, N, N-dibutylpropanolamine, N-methyldipropanolamine, N-
Ethyl dipropanolamine, 1- (2-hydroxyethyl) pyrrolidine, 2-methyl-1- (2-hydroxyethyl) pyrrolidine, 2-methyl-1- (3-hydroxypropyl) pyrrolidine, 1-piperidineethanol,
2-phenyl-1-piperidineethanol, 2-ethyl-1-piperidinepropanol, N-β-hydroxyethylmorpholine, 2-ethyl-N-β-hydroxypropyllmorpholine, 1-piperazineethanol, 1-piperazinepropanol, N N, N'-bis (β-hydroxyethyl) piperazine, N, N'-bis (γ-hydroxypropyl) piperazine, 2- (β-hydroxyethyl) pyridine, 2- (γ-hydroxypropyl) pyridine and the like. Preferably, tetrahydrofurfuryl alcohol, N, N-dimethylethanolamine, N, N-
Diethylethanolamine, 1-piperidineethanol.

In the catalyst composition used in the present invention, the barium compound of the component (a) is used in an amount of 0.05 to 1 mmol, preferably in terms of barium atom, per mole of the conjugated diene.
0.1-0.5 mmol.

The amounts of the components (b) to (d) used are expressed by the following ratio per mole of the barium compound (a). That is, the composition (molar ratio) of the catalyst composition used in the present invention is (component (a) / component (b) / component (c)).
Component / (d) component = 1 / 0.1 to 10/1 to 10/1 to 5, preferably component (a) / component (b) / component (c) / (d)
Component = 1 / 0.5 to 5/2 to 7 / 1.2 to 4, and more preferably 1/1 to 3/3 to 6 / 1.5 to 3.

Further, as a catalyst component, the above-mentioned (a)
To the (d) component, if necessary, a conjugated diene,
It may be used in a ratio of 0.05 to 20 mol per 1 mol of the component (a). As the conjugated diene used for preparing the catalyst, the same isoprene, 1,3-butadiene, 1,3-butadiene and the like as the monomer for polymerization are used. Although a conjugated diene as a catalyst component is not essential, the combined use thereof further improves the catalytic activity of the catalyst component.

The preparation of the catalyst comprises, for example, reacting the components (a) to (d) dissolved in an inert organic solvent and, if necessary, a conjugated diene.

At that time, the addition order of each component is not particularly limited,
(A) component → (d) component → (b) component → (c) component,
(A) component → (c) component → (b) component → (d) component,
It is preferable to add component (d) → component (a) → component (c) → component (b) or component (a) → component (d) → component (c) → component (b) in this order.

The component (d) can be handled in a state where the component (a) is previously mixed at a predetermined ratio.

These catalyst components are mixed and reacted in advance,
Aging is preferred from the viewpoint of improving the polymerization activity and shortening the period of inducing polymerization initiation, but each component of the catalyst may be added directly to the solvent and the monomer during the polymerization.

Conjugated dienes that can be polymerized with the catalyst system of the present invention include 1,1
3-butadiene, isoprene, 2,3-dimethyl-1,3-butadiene, 1,3-pentadiene, myrcene, etc.,
They can be used alone or in combination of two or more.
Butadiene and / or isoprene are preferred.

The conjugated diene polymer used in the present invention includes:
In addition to the conjugated diene, it is possible to copolymerize a vinyl aromatic compound such as styrene, α-methylstyrene, p-methylstyrene, o-methylstyrene, p-butylstyrene, and vinylnaphthalene. preferable.

The polymerization solvent is an inert organic solvent, for example, benzene, toluene, aromatic hydrocarbon solvents such as xylene, n-pentane, n-hexane, aliphatic hydrocarbon solvents such as n-butane, methylcyclopentane, Alicyclic hydrocarbon solvents such as cyclohexane and mixtures thereof can be used.

The polymerization temperature is usually -20 ° C to 150 ° C, preferably 30 ° C.
~ 120 ° C. The polymerization reaction may be a batch type or a continuous type.

The monomer concentration in the solvent is usually 5 to 50% by weight,
Preferably it is 10 to 35% by weight.

In addition, in order to prevent the deactivation of the catalyst system and the polymer of the present invention in producing the polymer, consideration should be given to minimizing the incorporation of compounds having a deactivating effect such as oxygen, water or carbon dioxide gas into the polymerization system. is required.

In the present invention, a conjugated diene is homopolymerized or an aromatic vinyl compound such as styrene and a conjugated diene are copolymerized in an inert organic solvent using the catalyst system comprising the components (a) to (d). To form a conjugated diene polymer.

The conjugated diene polymer thus obtained has a trans bond content of the diene portion of 70 to 90%, preferably 75 to 90%.
88%, vinyl bond content 3-10%, preferably 4-9
%, When the aromatic vinyl compound is copolymerized, the content of the bound aromatic vinyl compound is 50% by weight or less, preferably 5 to 45% by weight, more preferably 10 to 35% by weight.

If the trans-1,4-bond content of the diene portion of the conjugated diene polymer is less than 70%, the tensile strength and abrasion resistance are poor, while if it exceeds 90%, the resin becomes resinous and the hardness increases, and the vulcanized rubber Physical properties decrease.

If the vinyl bond content of the polymer is less than 3%, it is technically difficult to produce the polymer, while if it exceeds 10%, the tensile strength and wear resistance are poor.

Further, the bound aromatic vinyl compound content of the polymer is:
From the viewpoint of the tensile strength and rebound resilience of the vulcanized rubber, the content is preferably 5 to 45% by weight.

The molecular weight of the conjugated diene-based polymer obtained in the present invention can be changed over a wide range, and the weight average molecular weight in terms of polystyrene is usually 5 × 10
^{4 to} 100 × 10 ⁴ , preferably 10 × 10 ⁴ to 80 × 10 ⁴ and 5
If it is less than × 10 ⁴ , the tensile strength, abrasion resistance, rebound resilience, and heat generation of the vulcanized rubber are inferior, while if it exceeds 100 × 10 ⁴ , the workability is inferior, and the torque is excessive when kneading with rolls or Banbury. In addition, the temperature of the composition becomes high and the composition deteriorates, and the dispersion of carbon black becomes poor, resulting in poor performance of the vulcanized rubber.

The conjugated diene-based polymer obtained in the present invention has a molecular weight distribution (Mw / Mn) expressed as a ratio of the number average molecular weight (Mn) and the weight average molecular weight (Mw) in terms of polystyrene of 1.1 to 2.
It is 5 and less than 1.1 is technically difficult, while if it exceeds 2.5, the wear resistance decreases.

Furthermore, when the conjugated diene polymer obtained in the present invention is used particularly as an industrial rubber product, its Mooney viscosity (ML ^{1 + 4} , 100 ° C.) is usually 10 to 160, preferably 25 to 1
When it is less than 10, the physical properties of the vulcanized rubber are inferior, and when it exceeds 160, the processability is inferior.

The conjugated diene-based polymer obtained according to the present invention is prepared by blending the polymer alone or blended with another synthetic rubber or natural rubber as a raw material rubber, if necessary, oil-extending with a process oil, and then filling. A rubber composition is prepared by adding a conventional vulcanized rubber compounding agent such as carbon black, a vulcanizing agent and a vulcanization accelerator, and vulcanized, and is used for rubber applications requiring mechanical properties and abrasion resistance. Can be used.

〔Example〕

Hereinafter, the present invention will be described more specifically with reference to examples. However, the present invention is not limited to the following examples unless it exceeds the gist thereof.

In the examples, parts and% are based on weight unless otherwise specified.

Various measurements in the examples were based on the following methods.

The Mooney viscosity was measured at a preheating time of 1 minute, a measurement time of 4 minutes, and a temperature of 100 ° C. (according to JIS K6300).

The microstructure of the conjugated diene polymer was determined by an infrared absorption spectrum method (Morello method).

The bound styrene content was determined by infrared absorption spectroscopy.
A calibration curve was prepared and determined.

The weight average molecular weight and the number molecular weight were determined by gel permeation chromatography (GPC) (manufactured by Water Company, 244
) In terms of polystyrene.

The crystal melting point [Tm] of the conjugated diene polymer was measured using a differential scanning calorimeter (DSC).

Here, as a differential calorimeter, a 910 type Differential Scanning Calorimeter manufactured by DuPont, USA was used.
The recorder used was a 990 type thermal analyzer manufactured by DuPont. Sample volume is 10.0
mg ± 0.1 mg, and 10.15 mg of α-alumina (standard sample for DSC, manufactured by Shimadzu Corporation) was used on the reference side. The measurement was performed by inserting the sample and reference into an aluminum holder (manufactured by DuPont) at room temperature, loading the DSC, heating to + 180 ° C, and then cooling to -140 ° C at a rate of 10 ° C per minute. The analysis was performed at a heating rate of 20 ° C. per minute and a sensitivity of 2 mV / cm.

Example 1 Under a dry nitrogen atmosphere, 0.12 mmol of barium di (p-nonylphenoxide) was added as a component (a) while stirring with a magnetic stirrer in a 100 ml pressure bottle containing a rotor, and triethylaluminum was used as a component (b). , (C) ethyl butyl magnesium as a component,
As a component (d), diethylaminoethanol was added in the catalyst composition ratio shown in Table 1 in the order of catalyst addition, and a preliminary reaction was performed at 80 ° C. for 15 minutes (hereinafter referred to as “aging”) to prepare a catalyst.

Next, 175 g of cyclohexane and 25 g of 1,3-butadiene were added to a 300 ml pressure bottle under a dry nitrogen atmosphere. To this, the entire amount of the catalyst composition prepared above was added, and at 70 ° C., 90
Polymerized for minutes.

After completion of the reaction, di-t-butyl-p-
0.7 g of cresol is added to 100 g in terms of solid rubber,
After coagulation with methanol, it was dried at 40 ° C. under reduced pressure.

Table 1 shows the polymer yield, Mooney viscosity, microstructure of polybutadiene, and the results of GPC analysis.

Crystal melting point (Tm) by DSC (differential thermal analysis)
, Three points of 63 ° C, 45 ° C, and 33 ° C were observed.

Examples 2 to 3 Polymerization was carried out in the same manner as in Example 1 except that the order of addition of the four-component system was as shown in Table 1.

That is, the order of addition in Example 1 was changed from (a) component to
Component (c) → component (b) → component (d) (Example 2),
Component (d) → component (a) → component (c) → component (b) (Example 3).

The polymer yield and trans-1,4 bond content of the obtained polymer were high activity and high trans-1,4 bond content as in Example 1.

Comparative Examples 1 to 3 Polymerization was carried out in the same manner as in Example 1 except that the compound of the component (d) in Example 1 was not used and a three-component catalyst composition was used.

That is, in Comparative Examples 1 to 3, all (a) to
The composition ratio of the component (c) was changed, and the composition ratio was changed to (a)
Component / (b) component / (c) component = 1 / 1.5 / 4 (Comparative Example 1), 1/3/4 (Comparative Example 2), 1/3 / 1.5 (Comparative Example 3) Polymerization was carried out in the same manner as in Example 1, but the polymer yield was extremely low at 5% or less in each case. First result
It is shown in the table.

Comparative Example 4 Polymerization was carried out in the same manner as in Example 1, except that a three-component catalyst composition not using the organomagnesium compound (c) was used.

That is, in Comparative Example 4, the composition ratio was changed to (a) component /
Except that (b) component / (d) component = 1 / 1.5 / 2 and the addition order is (a) component → (d) component → (b) component,
Polymerization was carried out in the same manner as in Example 1, but no polymer was obtained. The results are shown in Table 1.

Comparative Example 5 Polymerization was carried out in the same manner as in Example 1 except that a three-component catalyst composition not using the organoaluminum compound (b) was used.

That is, in Comparative Example 5, the composition ratio was changed to (a) component /
The polymerization was carried out in the same manner as in Example 1 except that the component (c) / the component (d) = 1/4/2 and the addition order was changed from the component (a) to the component (d) → the component (c). However, no polymer was obtained. The results are shown in Table 1.

Comparative Example 6 Polymerization was carried out in the same manner as in Example 1 except that a three-component catalyst composition not using the barium compound (a) was used.

That is, in Comparative Example 6, the composition ratio was changed to (b) component /
Except that component (c) / component (d) = 1.5 / 4/2 and the order of addition is component (d) → component (b) → component (c),
Polymerization was carried out in the same manner as in Example 1, but no polymer was obtained. The results are shown in Table 1.

From the results of Examples 1 to 3 and Comparative Examples 1 to 6, the catalyst system composed of the four-component system of the component (a), the component (b), the component (c) and the component (d) of the present invention specifically Transformer-1
4 It can be seen that the bond content is high and the activity is high.

Example 4 Cyclohexane previously purified and dried by substituting nitrogen in a dry reactor having an inner volume of 5 liters equipped with a stirrer and a jacket.
2.000 g and 500 g of 1,3-butadiene were charged.

Next, under a dry nitrogen atmosphere, while stirring with a magnetic stirrer in a 100 ml pressure bottle containing a rotor,
(A) 2.4 mmol of barium di (p-nonylphenoxide) was added, and 12 mmol of 1,3-butadiene was added.

Further, (b) triethylaluminum, (c) ethylbutylmagnesium, and (d) diethylaminoethanol were added in the catalyst composition ratio and the catalyst addition order shown in Table 1,
The catalyst was prepared by aging at 80 ° C. for 15 minutes.

The same amount of the catalyst composition was similarly added to the reaction vessel, and polymerization was performed at 70 ° C. for 90 minutes.

Table 1 shows the polymer yield and the analysis results of the obtained polybutadiene.

Example 5 A copolymerization was carried out in the same manner as in Example 4 except that 125 g of styrene and 375 g of 1,3-butadiene were used instead of 1,3-butadiene.

Table 1 shows the copolymer yield and the analysis results of the obtained styrene-butadiene copolymer.

Example 6 In the same manner as in Example 4, cyclohexane and 1,3-butadiene were charged.

Next, after the temperature of the reaction vessel was raised to 55 ° C., the same amount of polymerization catalyst as in Example 4 was added, and polymerization was started.

Thereafter, the temperature was elevated while stirring at 2 revolutions per minute without cooling. After 30 minutes, the temperature in the reaction vessel reached 110 ° C, and the polymerization conversion of 1,3-butadiene was 84%. After that, the mixture was left for 30 minutes with stirring, and then the polymerization reaction was stopped.

Table 1 shows the polymer yield and the analysis results of the obtained polybutadiene.

Examples 7 to 11 Polymerization was carried out in the same manner as in Example 1 except that the kind of the organomagnesium compound as the component (c) was changed as shown in Table 1.

That is, as the component (d), diethyl magnesium (Example 7), dibutyl magnesium (Example 8), ethylhexyl magnesium (Example 9), ethyl magnesium chloride (Example 10), and phenyl magnesium bromide (Example 11) were used. Using. In each case, the polymer yield was 91% or more, and the trans-1,4 bond content was as high as 82 to 87%. The results are shown in Table 1.

Examples 12 to 15 Polymerization was carried out in the same manner as in Example 1 except that the type of the alcohol compound as the component (d) was changed as shown in Table 1.

That is, as the component (d), dibutylaminoethanol (Example 12), tetrahydrofurfuryl alcohol (Example 13), ethylene glycol monophenyl ether (Example 14), 1-piperidineethanol (Example 1)
5) was used.

In each case, the polymer yield was 93% or more, and trans-1,4
Very high bond contents of 84-87% were obtained. The results are shown in Table 1.

Examples 16 to 18 Polymerization was carried out in the same manner as in Example 1 except that the type of the barium compound (a) was changed as shown in Table 1.

That is, barium di-t-butoxide (Example 16), barium di (2-ethylhexanoxide) (Example 17), and barium di (p-butylphenoxide) (Example 18) were used as the component (a).

In each case, the polymer yield was 93% or more, and trans-1,4
Very high bond contents of 87-88% were obtained.

Test Examples 1 to 3, Comparative Test Examples 1 to 2 Polymers Obtained in Examples 4 to 6 (Test Examples 1 to 3)
Table 2 shows the results of vulcanization properties of high cis polybutadiene (Comparative Test Example 1) and solution-polymerized styrene-butadiene copolymer (Comparative Test Example 2).

The evaluation of the physical properties of the vulcanized product was carried out by using the raw rubber, kneading and compounding with a 230 cc Brabender and a 6-inch roll according to the following formulation, and then vulcanizing at 145 ° C. for 18 minutes. Various measurements were performed using the above. Formulation (Parts) Raw material rubber 100 Carbon black (HAF) 50 Stearic acid 2 Zinc white 3 Antioxidant (810NA) ^{* 1} 1 (TP) ^{* 2} 0.8 Vulcanization accelerator (DPG) ^{* 3} 0.6〃 (DM) ^{* 4} 1.2 Sulfur 1.5 * 1) N-phenyl-N'-isopropyl-p-phenylenediamine * 2) Sodium-dibutyldithiocarbamate * 3) Diphenylguanidine * 4) Dibenzothiazyl sulfide The tensile properties are based on JIS K6301. It was measured.

The rebound resilience is measured using a Dunlop trypsometer.
Rebound resilience at 80 ° C. was used.

The Lambourn abrasion index was measured using a Lambourn-type abrasion tester and represented by a wear amount at a slip rate of 25%, and the measurement temperature was room temperature. The higher the index, the better the wear resistance.

The internal loss (tanδ) was measured using a dynamic spectrometer manufactured by Rheometrics, Inc.
The measurement was performed under the conditions of 0.1%, a frequency of 10 Hz, and 50 ° C.

[Effects of the Invention] The present invention uses a catalyst composition containing (a) a barium compound, (b) an organoaluminum compound, (c) an organomagnesium compound, and (d) an alcohol-based compound as a polymerization catalyst, and comprises a conjugated diene. According to the present invention, a high trans low vinyl conjugated diene polymer having high polymerization activity, high trans-1,4 bond content, low vinyl bond content and high molecular weight can be easily produced according to the present invention.

Claims (1)

(57) [Claims] (A) a dialkoxy barium compound,
(B) an organoaluminum compound, (c) an organomagnesium compound, and (d) a general formula HOR (where R is an alkyl group having 4 to 20 carbon atoms or an aryl group having 6 to 20 carbon atoms, or an oxygen atom and / or Or a hydrocarbon residue having a nitrogen atom), a conjugated diene or a monomer composed of a conjugated diene and an aromatic vinyl compound in an inert organic solvent. A method for producing a conjugated diene-based polymer, characterized in that the polymerization is carried out by: