JPH0794518B2 - Complex polymerization method - Google Patents

Description

The present invention relates to a method for producing a composite polymer which is a raw material rubber having excellent physical properties and processability. More specifically, production of a composite polymer containing a block polymer composed of a polybutadiene block having a trans bond of 70% or more and a polybutadiene block having a trans bond of 60% or less and a polybutadiene having a trans bond of 60% or less as a main component. Regarding the method.

[Conventional technology]

The following three types of methods are known as polybutadiene having a high trans bond, for example, 70% or more of trans bond, and a method for producing the same. (1) Method using Gigler catalyst composed of transition metal compound and organometallic compound (2)
Method using an anionic polymerization catalyst containing an alkaline earth metal compound as a main component (3) Method using a catalyst containing a rare earth metal compound as a main component.

It is known that the above-mentioned (1) method is one in which a transition metal compound such as nickel, cobalt, titanium, or vanadium is the main component, and highly stereoregular polymerization is carried out. As a polymerization method of butadiene to be used, there is a method of using a carrier of a tetravalent titanium metal compound with magnesium halide (JP-A-51-67387).
Further, when the vanadium compound is the main component, a polymer having an extremely high trans bond content can be obtained. For example, a method of polymerizing isoprene using a composite catalyst of tetravalent vanadium halide and organoaluminum (Patent Document 1)
50-36585), and further, a method of polymerizing isoprene using a composite catalyst composed of a trivalent or tetravalent vanadium compound and an organoaluminum and a tetravalent titanium compound (Japanese Patent Laid-Open No. Sho 63-18753).
49-29386 and JP-A-50-122586) are known.

The method belonging to the second method (2) is mainly composed of barium, strontium and calcium compounds, such as barium-di-tert-butoxide and organolithium (JP-A-47-3728), or barium. -Di-tert-
There is an example in which butadiene is polymerized using butoxide and organomagnesium (Japanese Unexamined Patent Publication No. 52-48910), and further, an organic compound of barium or strontium and an organometallic compound of organolithium and a metal of II _B or III _A are used. There is also known a method of polymerizing a conjugated diene (JP-A-52-30543).

Further, as a method belonging to the third method, there is known a composite catalyst using a rare earth metal compound as a main catalyst and an organomagnesium compound as a cocatalyst. For example,
59-1508, Versatic acid salts such as Di, Nd, Pr,
Alternatively, a method using a special α, γ-diketone complex has been proposed.

Further, in JP-A-61-19611, compounds of cerium and europium are proposed, and in JP-A-61-97311, polymerization using a similar catalyst system with a lanthanum compound as a main catalyst is proposed, and a butadiene polymer having a high trans bond is proposed. Is efficiently obtained.

Further, it is also known to polymerize butadiene to 60% or less of trans bond using an organolithium compound as a catalyst, and details thereof are described in, for example, “The Stereo Rubber” Willimum,
M, Saltman, eds. 1977, Chapter 4. Here, butadiene polymerization with lithium metal or organolithium compound in a non-polar solvent gives a polymer with a trans bond of 48 to 50% and addition of a polar compound to this system increases the 1,2 bond. And 1,4 binding has been reported to be reduced.

There is also a proposal regarding a composite polymer containing a block polymer of a butadiene copolymer having a high trans bond and a butadiene copolymer having a high vinyl bond as one of the components and a method for producing the same (JP-A-61-238845). According to the specification (Claim 1), "a composition containing a rubber polymer selected from the group consisting of:

I. High trans / high vinyl diblock copolymers.

II. Blends of high trans copolymers and high vinyl polymers.

III. Blends or mixtures of high trans / high vinyl diblock copolymers, high trans copolymers, and high vinyl polymers.

a). Here, the high-trans copolymer is butadiene-1,3
-And a copolymer of at least one copolymerizable monomer selected from the group consisting of styrene and isoprene, having a Tg of less than about -70 ° C and having a Tg of less than about 75 to 85% in the butadiene segment. It has a total content of trans units and vinyl units up to about 8% and comprises 25 to 80% by weight of the composition.

b). The high vinyl polymer is at least one polymer selected from the group consisting of copolymers of homopolybutadiene and at least one monomer selected from the group consisting of styrene and isoprene, and butadiene-1,3-, About −70
It has a Tg of more than about -35 ° C and not more than about -35 ° C, with about 40 to 80% vinyl units in the butadiene segment.

c). In the composition, the total amount of styrene and / or isoprene is about 5 to about 20% by weight, and the total amount of vinyl groups is about 30 to 60%. ] And a method for producing this polymer composition is set forth in claim 9 thereof, the gist of which is shown in the specification as follows.

"The production method of HTSBR-b-HVSBR copolymers is about 60 to 95
%, Preferably about 85% conversion of butadiene and styrene in cyclohexane using a barium salt of an alcohol in combination with an organomagnesium compound and an organoaluminum compound, or an organomagnesium / organoaluminum complex. HTSBR (Block A) is formed, followed by addition of sodium (preferred), potassium or rubidium alcoholate, or mixtures thereof, and a strong Lewis acid, and optionally additional monomer to form HVSBR (Block B). It consists of The resulting SBR has predominantly randomly distributed styrene units in each block. The high content of the trans-1,4 configuration in block A causes some crystal temperature, as observed from DSC (differential scanning calorimetyy) and crystal melting point, but the crystal melting point does not It can be lowered to near or below room temperature (about 25 ° C) by adjusting the -1,4 content and styrene level. The resulting polymers have reduced cold flow and excellent processability. [Problems to be Solved by the Invention] However, in the above method, the first block of the obtained polymer is a high trans copolymer, so that the Tg value is higher than that of a homopolymer. , Tm value (crystal melting point) is also low or nonexistent, and it has excellent physical properties (improvement in cold flow property, hardness, modulus, abrasion resistance, etc.) as a rubber brought by a high trans block part. Insufficient expression. On the contrary, an increase in the ratio of the high-trans copolymer portion, which is higher than necessary for exhibiting the effect, is not preferable because it causes exothermicity and lowers low-temperature performance.

In addition, the second block is also HVSBR which is a polymer with a high vinyl content inevitably when the second stage polymerization for forming this block is carried out by adding sodium alcoholate or the like, and generally cold flow, It cannot be applied to BR (polybutadiene rubber) or SBR (styrene-butadiene copolymer rubber) having a low vinyl content, which requires the most improvement in hardness, modulus and strength.

[Means for Solving the Problems]

DISCLOSURE OF THE INVENTION The present invention is a block copolymer comprising a polybutadiene block having a trans bond of 70% or more and a polybutadiene block having a trans bond of 60% or less and 60% having excellent physical properties and processability, which can solve the above problems all at once.
It proposes a method for producing a composite polymer containing the following polybutadiene having a trans bond as a main component. That is, the present invention provides: (a) a step of preparing a monomer mixture solution comprising butadiene and an inert solvent; (b) a catalyst containing a barium, strontium or calcium compound and an organolithium compound or an organomagnesium compound, and a catalyst content of 0 to 150. 70% butadiene at a temperature of ℃
The step of polymerizing to the trans bond as described above, (c) subsequently, adding an organolithium compound to the catalyst to polymerize butadiene to a trans bond of 60% or less at a temperature of 30 to 200 ° C., (d) The method for producing a composite polymer comprises the step of removing an inert solvent from the composite polymer.

The first step in the present invention is a step of preparing a monomer mixture liquid comprising butadiene and an inert solvent, and the inert solvent used is not particularly limited as long as it does not deactivate the catalyst used, but n-pentane, n -Hexane, n-
Aliphatic or alicyclic hydrocarbons such as heptane and cyclohexane, and aromatic hydrocarbons such as benzene and toluene are preferable. Further, these may be a mixture of two or more kinds, or may contain a small amount of impurities. Monomer mixture has a monomer concentration of 1 to 50% by weight, preferably 5 to 30% by weight
Arenes having a molar ratio to the organolithium compound of 1 or less, for example, propadiene, 1,2-
It may contain butadiene, 1,2-pentadiene, 1,2-octadiene and the like. Furthermore, isoprene, 2,3-dimethyl-1,3-butadiene, 1,3-pentadiene, 2,4 as a monomer component copolymerizable with a small amount of other butadiene as a polymer component other than butadiene in the mixed liquid. -Hexadiene, a conjugated diene of 2-phenyl-1,3-butadiene, or styrene, α-methylstyrene, vinyltoluene, methoxystyrene, divinylbenzene, 1-
It may contain an aromatic vinyl hydrocarbon such as vinylnaphthalene.

The second step of the present invention is a step of polymerizing butadiene to 70% or more of trans bond at a temperature of 0 to 150 ° C. with a catalyst containing a barium, strontium, calcium compound and an organolithium compound or an organomagnesium compound. is there. The catalyst that can be used in this step is a catalyst containing barium, strontium, a calcium compound and an organolithium or organomagnesium compound capable of polymerizing butadiene in the following high trans, for example (a) barium dioxide Catalyst composed of tertiary putoxide and organolithium (Japanese Patent Publication No. 47-3728) (b) Catalyst composed of barium ditertiary alkoxide and dibutylmagnesium (Japanese Patent Publication No. 52-48910) (c) Consists of the following barium compound and organolithium Catalyst (JP-A-52-9090) (D) A catalyst comprising a barium or strontium compound and an organolithium compound and an organometallic compound of IIB or IIIA (Japanese Patent Publication No. 52-30543) (e) Me (MR ¹ R ² R ³ R ⁴ ) ₂ or Me (M ' R _'4) (Me in the formula of barium, calcium, strontium, M
Represents boron or zinc) and a catalyst comprising organolithium (JP-A-52-17591) (f) Compounds of barium, strontium or calcium with organolithium and organometallic compounds of IIB or IIIA, alkali metal alcoholates, etc. (Catalyst: JP-A-52-98077) (G) A catalyst comprising an organic compound of barium and an organic lithium / magnesium compound, or a catalyst further comprising an organic aluminum compound (JP-A-55-38827,
JP-A-56-112916).

Preferred barium, strontium and calcium compounds used in the present invention are organic compounds of barium and can be represented by the following formula, and particularly preferred are barium alcoholates or phenol salts.

(A) BaY-R) ₂ (In the formula, R is selected from an aliphatic, alicyclic or aromatic hydrocarbon group, and Y is an oxygen or sulfur atom).

Examples of these include barium salts of the following compounds.

That is, ethyl alcohol, n-propyl alcohol, isopropyl alcohol, tert-butyl alcohol, n-hexyl alcohol, cyclohexyl alcohol, allyl alcohol, cyclopentenyl alcohol,
Benzyl alcohol, phenol, catechol, 1-naphthol, 2,6-di-tert-butylphenol, 2,
4.6-Tri-tert-butylphenol, nonylphenol, 4-phenylphenol, ethanetyl, 1-butanetyl, thiophenol, cyclohexanethiol, 2-naphthalenethiol, caprylic acid, lauric acid, myristic acid, palmitic acid, stearic acid, olein Acid, linoleic acid, linoleic acid, naphthoic acid, benzoic acid, hexanechilic acid, decanthilic acid, tridecanethionoic acid, thiobenzoic acid, tert-butyl acid carbonate,
Hexyl acid carbonate, phenyl acid carbonate, thio acid carbonate te
rt-butyl, dimethylamine, diethylamine, di-n
-Butylamine and the like.

In addition, examples of the organic lithium compound include the following. That is, ethyl lithium, n-propyl lithium, iso-propyl lithium, n-butyl lithium, isoamyl lithium, sec-amyl lithium, n
-Hexyllithium, n-octyllithium, allyllithium, n-propenyllithium, iso-butenyllithium, benzyllithium, phenyllithium, 1,1-diphenyllithium, tetramethylenedilithium, pentamethylenedilithium, hexamethylenedilithium , Diphenylethylenedilithium, tetraphenylethanedilithium, 1,5-dilithium naphthalene, 1,4-dilithiocyclohexane, polybutagenyllithium, polyisobutenyllithium, polystyryllithium and the like.

Further, the organomagnesium compound can be represented by the following formula.

R ₂ Mg, where R is selected from an aliphatic, alicyclic or aromatic hydrocarbon group.

Examples of the organic magnesium compound include the following. That is, diethyl magnesium, di-n-propyl magnesium, di-iso-propyl magnesium, di-n-butyl magnesium, di-tert-butyl magnesium, di-n-hexyl magnesium, di-n-propyl magnesium, diphenyl magnesium, etc. is there.

In the present invention, when the organolithium compound and the organomagnesium compound are used in combination, they are mixed in advance,
It is a preferred embodiment that the reaction is utilized as an organic lithium-magnesium compound to enhance the solubility of the catalyst in the polymerization solvent. In this embodiment, it is also a useful method to use an organoaluminum compound in combination. An example thereof is an organoaluminum compound represented by the following formula, and a particularly preferable one is trialkylaluminum.

R ₃ Al, where R is selected from an aliphatic, alicyclic or aromatic hydrocarbon group.

The following are mentioned as an example of an organoaluminum compound. That is, tri-iso-butylaluminum, tri-n-propylaluminum, tri-iso-propylaluminum and the like.

The amount of catalyst used in the present invention is barium, strontium,
Or with calcium compounds for 100 grams of monomer
It is preferably 0.005 to 50 or 0.01 to 10 mmol.

Polymerization is carried out using the above catalyst at 0 ° C to 150 ° C, preferably 30
It is carried out at ˜120 ° C., and the polymerization mode may be a batch method or a continuous method. The polymerization is performed by polymerizing butadiene to a trans bond of 70% or more, and the ratio of the high trans polymer to be polymerized in the step (b) in the total composite polymer is 1 to 70% by weight, preferably 3 to The polymerization is allowed to proceed to 60% by weight, more preferably 5 to 50% by weight.

In the next step (c), an organolithium compound is further added to the above catalyst, and butadiene is polymerized to a trans bond of 60% or less at a temperature of 30 to 200 ° C. Preferred examples of the organolithium compound additionally added include methyllithium, ethyllithium, n-propyllithium, isopropyllithium, n-butyllithium, sec-butyllithium, tert-butyllithium, isoamyllithium, and se.
c-amyllithium-n-hexyllithium, n-octyllithium, allyllithium, penzyllithium, phenyllithium, 1,1-diphenyllithium, citramethylenedilithium, pentamethylenedilithium, 1,2-
Examples thereof include dilithio-1,1,2,2-tetraphenylethane and 1,3-bis (1-lithio-1,3-dimethylpentyl) benzene. Preferably, n-butyllithium, sec-
Organolithium compounds such as butyl lithium, tert-butyl lithium, and 1,3-bis (1-lithio-1,3-dimethylpentyl) benzene can be mentioned.

The amount added is 0.1 to 10 millimoles, preferably 0.3 to 5 millimoles, per 100 grams of monomer. Further, a Lewis base can be used for the purpose of enhancing the polymerization activity of the catalyst at the same time as the organolithium compound added thereafter, or enhancing the 1,2 vinyl bond and further lowering the trans bond. Suitable Lewis bases include ethyl, thioethers and amines, and examples thereof include dimethyl ether, diethyl ether,
Ethers such as diphenyl ether, tetrahydrofuran, anisole, diglyme, dimethylamine, diethylamine, trimethylamine, triethylamine, di-n-butylamine, aniline, diphenylamine, N
-Ethylaniline, N, N, N ', N'-tetramethylethylenediamine, amines such as dipiperidinoethane, and further thioethers such as thiophene, tetrahydrothiophene and 2,5-dihydrothiophene. it can. Preferred are diethyl ether, tetrahydrofuran, triethylamine and N, N, N ', N'-tetramethylethylenediamine. The amount of the electron-donating compound used varies depending on the strength of the compound as a Lewis base, but generally speaking, the strongly basic compound may be used in a small amount as compared with the weakly basic compound. The preferred usage is
It is about 0.01 to 50 mol per mol of the organic lithium compound. Polymerization was carried out with a catalyst to which the above-mentioned organic lithium was added.
It is carried out at a temperature of ~ 200 ° C, preferably 50-150 ° C.
At this stage, the monomer mixture prepared in the step (a) or the monomer mixture prepared in another composition may be introduced into the polymerization system.

In this case, both the unreacted residual monomer in the step (b) and the monomer introduced in the step (c) are (c)
Polymerized in the process. The monomer polymerized in the step (c) is butadiene alone or a mixture of butadiene and a monomer copolymerizable with butadiene, and examples of the monomer copolymerizable with butadiene include isoprene, 2,3-dimethyl-1,3- Conjugated dienes such as butadiene, 1,3-pentadiene, 2,4-hexadiene, 2-phenyl-1,3-butadiene, etc., or styrene, α-methylstyrene, vinyltoluene, methoxystyrene, divinylbenzene, 1-vinylnaphthalene, etc. Is an aromatic vinyl hydrocarbon.

Polymerization at this stage is carried out with butadiene having a trans bond content of 60% or less, preferably 55% or less, preferably cis bond content of 40% or less.
Hereinafter, a vinyl bond is polymerized to 10 to 85%, and the ratio of the low-trans polymer polymerized in the step (c) in the total composite polymer is 30 to 99% by weight, preferably 40 to 97%.
Polymerization is allowed to proceed so that the amount becomes 50% by weight, more preferably 50 to 95% by weight.

After the polymerization reaction reaches a predetermined polymerization rate, a known polymerization terminator may be added to the reaction system to stop the polymerization, and the usual steps of solvent removal and drying in the production of the conjugated diene polymer may be performed.

The composite polymer obtained by the method of the present invention is a block polymer comprising a rubber-like or resin-like polybutadiene block polymerized to a high trans bond of 70% or more and a rubbery polybutadiene block polymerized to a trans bond of 60% or less, and The main component is polybutadiene having a trans bond of 60% or less, and the molecular weight of the polymer can be controlled by adjusting the composition or concentration of the catalyst used, and is in the range of several thousands to several hundreds of thousands. Further, the molecular weight distribution of the polymer can be controlled by adjusting the composition of the catalyst to be used, and Mw / Mn is in the range of 1.1 to 5.0, but in order to obtain preferable physical properties, it should be in the range of 1.1 to 4.0. Is. Known coupling reaction techniques such as ester compounds, polyepoxy compounds, halogenated hydrocarbon compounds, halogenated silicon compounds and tin halide compounds are used as coupling agents utilizing reactive ends of living polymers or polyfunctional compounds such as divinylbenzene. It is also possible, if necessary, to impart a branched structure to the polymers or to broaden the molecular weight distribution by a method of adding a polymerizable monomer to the polymerization system during or after the polymerization.

The applications of the polymers obtained by the process of the present invention are widespread due to their polymer structure and properties. For example, it can be used as a rubber-like polymer for tire treads, carcasses, sidewalls and the like, and exhibits excellent properties such as processability, abrasion resistance and heat generation.

Even as a toughening agent that improves the impact resistance of polystyrene etc., it does not show any cold flow properties, and has excellent particle size controllability, a balance of rigidity and impact resistance, and excellent environmental stress crack resistance (ESCR) resistance to oil. Of high quality polystyrene (HIPS).

〔Example〕

Hereinafter, the present invention will be specifically described with reference to examples, but the present invention is not limited to these examples.

Examples 1 to 3 Three fully dried 700 ml pressure-resistant glass bottles were capped,
Further, the inside was purged with dry nitrogen for 3 hours. After encapsulating 300 gn-hexane mixed solution containing 60 g of 1,3-butadiene in a bottle, barium strontium and calcium dinonylphenoxide 0.1 mmol, n-butyllithium 0.15 mmol, dibutylmagnesium, 0.15 mmol were added to each, and Polymerization was carried out at ℃ for 2 hours. After sampling a part, this was further added with n-butyl lithium, 1.0
The mmol was additionally added, and the polymerization was carried out at 100 ° C. for another hour. After the polymerization, methanol was added to stop the reaction, and the polymer was precipitated and separated with a large amount of methanol, followed by vacuum drying at 50 ° C. to obtain a composite polymer. Table 1 shows the analytical values of this composite polymer and those sampled during the process.

Example 4 Two stirrers and jacketed reactors made of stainless steel having an internal volume of 10 liters and a height-to-inside diameter ratio of (L / D) 4 were connected in series, and from the bottom of the first unit 1, A solution of 3-butadiene in n-hexane and barium dinonylphenoxide, dibutylmagnesium, butyllithium and triethylaluminum as a catalyst were continuously fed, and the internal temperature was kept at 70 ° C to carry out polymerization. The concentration of the monomer mixed liquid was 18% by weight, and the monomer feed rate was 0.67 kg / hr. The feed amount of the catalyst was 0.15 mmol for barium nonylphenoxide, 0.20 mmol for dibutylmagnesium, 0.20 mmol for butyllithium, and 0.30 mmol for triethylaluminum per 100 g of the monomer.

The conversion was measured by sampling from the outlet of the first reactor, and the conversion was 33.4%. The microstructure of the obtained polymer was 85% trans, 4% vinyl, and 11% cis. The average molecular weight by GPC was Mw = 55,000 and Mn = 22,000, and the GPC type had one gentle peak.

The polymer solution discharged from the first base was introduced into the bottom of the second base, and further an additional n-hexane solution of 1,3-butadiene and n-butyllithium were introduced from the bottom of the second base. The concentration of the monomer mixture introduced into the second group was 18% by weight, and the monomer feed rate was 0.67 kg / hr. The amount of butyllithium introduced into the second group was 2.
It was set to 0 mmol. After keeping the temperature inside the second reactor at 120 ° C. to carry out polymerization, 2,4-ditertiary-butyl-p-cresol was added to the polymer solution discharged from the second reactor.
0.6 phr (parts by weight per 100 parts by weight of rubber) were mixed continuously, introduced into hot water and steam stripped to remove the solvent. The obtained rubber was dried on a hot roll.

The conversion at the second exit was 99.8%. The microstructure of the rubber obtained is 57% transformer, 11% vinyl,
Cis 32%, Mooney viscosity ML _{1 + 4} (100 ℃) 30, GP
The average molecular weight by C is Mw = 160,000, Mn = 67,000, and GPC
The shape was a gentle mountain.

An attempt was made to fractionate a 1/1 blend of the final polymer of Example 4, the intermediate sampling polymer of Example 4, and a polymer having a trans content of 52% and a weight average molecular weight of 100,000 polymerized by n-butyllithium alone. 2 g of each polymer was dissolved by heating in 100 ml of n-hexane / cyclohexane mixed solvent and then dissolved in 0
It was cooled to ℃ and centrifuged to separate into a precipitate and a solution. The analytical values of this product are shown in Table 2. It is suggested from Table 2 that the final polymer of Example 1, the composite polymer, contains almost no high trans resinous polybutadiene homopolymer, and the main component is a block polymer.

As described above, the obtained rubber was a composite polymer containing a block polymer composed of 15% by weight of polybutadiene block containing 85% of trans and 85% by weight of polybutadiene block containing 50% of trans as a main component.

When the cold flow of the obtained rubber was measured, substantially no cold flow was observed.

Rubber of Example 4: No cold flow even after 3 days Diene 35 (commercial item): Collapses in half a day.

(A 3 cm × 3 cm × 10 cm (height) rectangular parallelepiped rubber sample was fixed on an inclined table of 30 ° and the inclined state was observed.) Example 5 The same reactor as in Example 4 was used, and the same procedure was performed. The first polymerization was carried out.

Similarly, the polymer solution discharged from the first base is introduced into the bottom of the second base, and from the bottom of the second base, an additional monomer mixture solution of 1,3-butadiene, styrene, and n-hexane and n-butyllithium are added. Introduced. The concentration of the monomer mixture was 26% by weight, the feed rate of 1,3-butadiene was 0.69 kg / hr, and the feed rate of styrene was 0.46 kg / hr. In addition, an additional monomer mixture solution of 1,3-butadiene and n-hexane was introduced from a position 2/3 from the bottom of the height of the second reactor. The concentration of this monomer mixture was 26% by weight, and the feed rate of 1,3-butadiene was 0.41 kg / hr.

The amount of n-butyllithium introduced at the base of 2 was 2.0 mmol per 100 g of all the monomers introduced at the 2nd group. Polymerization was carried out while maintaining the internal temperature of the second reactor at 120 ° C., and then the polymer solution discharged from the second reactor was added to 2,4-ditertiary-butyl-butanol in the same manner as in Example 5. p-Cresol was added and a rubber was obtained in the same manner.

The conversion at the second outlet is 99 for 1,3-butadiene.
It was 5% and styrene was 98.5%. The microstructure of the obtained rubber was measured by the method of Hampton using an infrared spectrophotometer. As a result, the bonded styrene was 20.5% by weight, and the polybutadiene part had a microstructure of trans 57%, vinyl 11%, cis 32%.
%, The Mooney viscosity was ML _{1 + 4} (100 ° C.) 40, the average molecular weight by GPC was Mw = 170,000, Mn = 73,000, and the GPC type had a gentle peak. The block styrene content was 0.1% by weight based on the total rubber. The block styrene was measured by the osmium acid decomposition method (J. Po.
ly.Sci.1,429 (1946). When the obtained composite polymer was fractionated in the same manner as in Example 4, the precipitation was 1.3% by weight based on the composite polymer, suggesting that the present polymer is also a block polymer.

As described above, the obtained rubber is composed of 10% by weight of polybutadiene block containing 85% of trans, 25% by weight of bonded styrene, and 90% of random SBR block containing 52% of trans in the polybutadiene part.
It was a composite polymer whose main component was a block polymer composed of wt%.

Comparative Example 1 A sufficiently dried 700 ml pressure resistant glass bottle was capped, and the inside was purged with dry nitrogen for 3 hours. After filling a 135g cyclohexane mixture containing 23g 1,3-butadiene and 4g styrene in a bottle, a Ba-Mg-Al initiator (Ba / Mg / Al = 0.18
/0.57/0.04 unit mmol / 100g monomer, U.S. Pat.
No. 7,240) was added and polymerization was carried out at 60 ° C. for 1 hour. After sampling a part,
A 165 g cyclohexane mixed solution containing 33 g of 1,3-butadiene and a cyclohexane solution of Ma tertiary amylate and TMEDA (Na / Mg molar ratio = 0.77, TMEDA / Mg molar ratio 0.61) were added. Polymerization was carried out at 50 ° C. for 1 hour.
Then, methanol was added to stop the reaction, and a polymer was obtained in the same manner as in Example 1. Table 3 shows the analytical values of the obtained polymer and the sample obtained in the middle.

Comparative Example 2 The procedure of Comparative Example 1 was repeated.

However, a Ba-Mg-Al initiator was added, polymerization was carried out at 60 ° C for 5 hours, and Na ternary amylate and TMEDA were added to the mixture.
Polymerization was carried out at 0 ° C. for 1 hour. The results are shown in Table 3.

The TSBR polymer sampled on the way was the same as in Example 1,
From the method using the n-hexane / cyclohexane mixed solvent, crystallization by trans did not occur and the precipitate could not be decomposed. The same was true for the finally obtained polymer. The cold flow property of the obtained polymer was evaluated by the method shown in Example 4, and "it collapses in one day."
However, it was not preferable.

[Effects of the Invention] As is clear from the above Examples and Comparative Examples, the composite polymerization method of the present invention is a composite polymer BR (polybutadiene rubber) or SB having a relatively low vinyl content and excellent cold flow properties.
An extremely efficient method for obtaining R (styrene-butadiene copolymer rubber) is provided.

Claims (1)

[Claims] 1. A process of preparing a monomer mixture liquid comprising (a) butadiene and an inert solvent, (b) a catalyst containing a barium, strontium, calcium compound and an organolithium compound or an organomagnesium compound at 0 to 150 ° C. 70% butadiene under temperature
The step of polymerizing to the trans bond as described above, (c) subsequently, adding an organolithium compound to the catalyst to polymerize butadiene to a trans bond of 60% or less at a temperature of 30 to 200 ° C., (d) A method for producing a composite polymer, comprising the step of removing an inert solvent from the composite polymer.