JPH0791340B2 - Method for producing conjugated gen polymer - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention provides a conjugated gen polymer having a high cis-1,4 bond content and a narrow molecular weight distribution and exhibiting excellent rubber properties with extremely high efficiency. The present invention relates to a manufacturing method.

[Conventional technology]

Many methods are already known as methods for producing a conjugated gen polymer having a high 1,4-cis bond content. Particularly, a butadiene polymer obtained by using a composite catalyst containing a transition metal compound such as nickel, cobalt or titanium as a main component generally has a cis bond content of more than 90%,
It is industrially produced together with a low cis butadiene polymer using a lithium-based catalyst and is widely used for various purposes.

As another method for producing a high cis butadiene polymer, a method using a composite catalyst containing a rare earth metal compound as a main component is also known. The butadiene polymer obtained in this case is
It is said that it has a feature that it is excellent in adhesiveness as compared with a high cis butadiene polymer obtained by a transition metal catalyst.

(Kautschuk und Gummi Kunststoffe, Vol. 22, p. 293, 1
(Published in 969) However, the solubility of the rare earth metal compound, which is the main component of this type of composite catalyst, or the overall polymerization system of these composite catalysts is not sufficient, and the catalyst activity may become nonuniform. Was inadequate. Further, the obtained butadiene polymer has a wide molecular weight distribution, and therefore, the rubber performance such as elastic properties is not particularly excellent as compared with general high cis butadiene rubber.

Various attempts have already been made to improve the drawbacks of these composite catalysts containing a rare earth metal as a main component. For example, a method of improving the activity by preliminarily reacting a polymerization catalyst in the presence of a small amount of conjugated gen before adding it to the polymerization system (Japanese Patent Publication No. 47-14).
No. 729), a method of using a rare earth metal alcoholate as a main component of the composite catalyst, a method of using a neodymium phenol salt, or a method of dissolving the composite catalyst by using a specified tertiary carboxylate of neodymium. Method with improved properties (JP-A-54-40890, JP-A-60-1)
08408, JP 55-66903 A) and the like are known.

Furthermore, by using a composite catalyst whose main component is a reaction product of a rare earth metal carboxylate and a Lewis base such as acetylacetone, the solubility of the polymerization catalyst in a hydrocarbon solvent is improved, and high polymerization activity is achieved. It is disclosed that this can be done. (Japanese Patent Application Laid-Open No. 58-1709) [Problems to be Solved by the Invention] As described above, a composite catalyst containing a rare earth metal compound as a main component, particularly a composite catalyst containing a rare earth metal carboxylate compound as a main component, It is already known that a conjugated gen polymer having a high cis content can be obtained. However, in order to achieve high catalytic activity, special operations such as preliminary reaction or catalyst aging are required. Industrially, this operation such as pre-reaction or catalyst aging complicates the production process, and causes problems such as a decrease in production efficiency and an increase in production cost. there were. Further, further improvement in the polymerization activity has been demanded.

[Means for Solving the Problems]

The present inventor, as a result of extensive studies to solve the above problems, some acid groups of the rare earth metal carboxylate compound, the acidity is lower than the carboxylic acid, and in the absence of water and the like. By substituting with another organic acid group having sufficient acidity to form a stable salt with a rare earth metal, the resulting rare earth metal complex salt has excellent solubility in a polymerization catalyst, etc. Has reached the present invention by finding that extremely high catalyst activity can be achieved without requiring special operations such as preliminary reaction or catalyst aging.

The excellent action and effect achieved by the present invention, that is, the excellent solubility of the rare earth metal complex salt in a polymerization solvent and the high polymerization activity as a complex initiator, surprisingly make up the carboxylic acid constituting the rare earth metal complex salt. It is not achieved at all by separately adding the rare earth metal salt of and the rare earth metal salt of another organic acid compound to the polymerization system, but it is achieved only by using the specific complex salt provided by the present invention. It is what is done.

That is, in the present invention, in bulk polymerization or solution polymerization of a conjugated gen in a hydrocarbon solvent, (a) a complex salt compound with a carboxylic acid compound of a rare earth metal and another organic acid compound is prepared in advance, Provided is a method for producing a conjugated gen polymer, which comprises allowing a composite catalyst comprising a salt compound, (b) an organoaluminum compound, and (c) a halogen-containing Lewis acid compound to be present.

Here, the complex salt compound with a carboxylic acid compound of a rare earth metal and another organic acid compound is represented by the general formula LnA ₁ B ₂ or LnA ₂ B ₁
Ln is a rare earth metal, A is an acid group of a carboxylic acid compound, and B is an acid group of an organic acid compound other than the carboxylic acid having a lower acidity than the corresponding carboxylic acid.

The rare earth metal constituting the component (a) of the composite catalyst is an element having an atomic number of 57 to 71, preferably an atomic number of 57 to 60.
And the most preferred metal is neodymium. The rare earth metals that can be used may be a mixture of rare earth metals with each other or may naturally contain a small amount of another metal.

Other organic acid compounds that can be substituted with carboxylic acid compounds preferably have a specific acidity of 25 ° C. and an acid dissociation index pKa in water of 5 or more, more preferably 5 to 2
It can be chosen from organic acid compounds having an acidity in the range 0, particularly preferably in the range 8-12. The term “organic acid” as used herein generally refers to an organic compound capable of forming a salt with a rare earth metal. Specific types of organic acid compounds within this range include phenol, alcohols and their sulfur homologs. When the acidity of the substituting organic acid compound is stronger than pKa5, the high catalytic activity, which is a feature of the present invention, may not be sufficiently exhibited. If the acidity of the organic acid compound to be replaced is weaker than pKa20, the stability of the rare earth metal composite compound during production or storage may decrease.

A particularly preferred type of organic acid compound that can be substituted for the carboxylic acid compound is a phenol compound.

These rare earth metal complex salt compounds include, for example, a mixture of a sodium salt of a corresponding carboxylic acid compound and a sodium salt of a corresponding other organic acid compound in a solution of a rare earth metal hydrochloride and an alcohol or acetone. It can be easily obtained by reacting.

A flow chart showing this reaction is shown in FIG.

The carboxylic acid compounds constituting the component (a) of the composite catalyst are the carboxylic acid compounds represented by the following general formula (I) and their sulfur homologs.

Here, R ¹ is an aliphatic hydrocarbon group, an alicyclic hydrocarbon group having 3 to 30 carbon atoms, preferably 4 to 20 carbon atoms, or 6 carbon atoms.
Represents an alkyl-substituted aromatic hydrocarbon group in the range of -30, preferably 7-20.

L represents an oxygen or sulfur atom. Specific preferred examples thereof include isovaleric acid, caprylic acid, octanoic acid, lauric acid, myristic acid, palmitic acid, stearic acid, isostearic acid, oleic acid, linoleic acid, cyclopentanecarboxylic acid, naphthenic acid, ethylhexanoic acid, Pivalic acid, versatic acid (synthetic acid composed of a mixture of isomers of C10 monocarboxylic acid sold by Shell Chemistry), phenylacetic acid, benzoic acid, 2-naphthoic acid, hexanethiolic acid, 2,2-dimethylbutane Examples thereof include thionic acid, decanothioic acid, tetradecanothioic acid and thiobenzoic acid.

The alcohol, the phenol compound and the sulfur homologue thereof are represented by the general formula (II).

R ² -LH (II) Here, R ² has 2 to 30 carbon atoms, preferably an aliphatic hydrocarbon group, alicyclic hydrocarbon group having 4 to 20 carbon atoms, or 6 carbon atoms.
Represents an alkyl-substituted aromatic hydrocarbon group in the range of -30, preferably 7-20. L represents an oxygen or sulfur atom.
Specific examples include ethyl alcohol, n-propyl alcohol, iso-propyl alcohol, tert-butyl alcohol, tert-amyl alcohol, n-hexyl alcohol, cyclohexyl alcohol, allyl alcohol, 2-
Butenyl alcohol, 3-hexenyl alcohol, 2,5
-Decaenyl alcohol, benzyl alcohol, phenol, catechol, 1-naphthol, 2-naphthol, 2,6-di-tert-butylphenol, 2,6-di-tert
-Butyl-4-methylphenol, 2,4,6-tri-tert
-Butylphenol, 4-phenylphenol, ethanethiol, 1-butanethiol, 2-pentanethiol, 2-iso-butanethiol, thiophenol, 2-
Examples thereof include naphthalenethiol, cyclohexanethiol, 3-methylcyclohexanethiol, 2-naphthalenethiol, benzenemethanethiol, 2-naphthalenemethanethiol.

The component (a) of the composite catalyst of the present invention is preferably a composite salt compound alone with a carboxylic acid compound of a rare earth metal and another organic acid compound. However, a salt of a carboxylic acid compound of a rare earth metal or a salt of another organic acid compound alone may be included as an impurity. However, even in this case, the complex salt compound is at least 50 mol%, preferably
The object of the present invention cannot be sufficiently achieved unless the content is 75 mol% or more, particularly preferably 85% or more.

Further, it goes without saying that an unreacted organic acid compound may be contained as an impurity as long as the object of the present invention is not impaired.

The organoaluminum compound which is the component (b) constituting the composite catalyst of the present invention is represented by the general formula (III).

▲ Al R ³ _3-n ▼ H _n (III) Here, R ³ has 1 to 20 carbon atoms, preferably an aliphatic hydrocarbon group, alicyclic hydrocarbon group having 2 to 8 carbon atoms, or 6 to 6 carbon atoms.
It represents an alkyl-substituted aromatic hydrocarbon radical in the range of 20, preferably 6-12. n is 0, 1 or 2, preferably 0 or 1, and H represents a hydrogen atom.

Preferred organic aluminum compounds include trimethyl aluminum, triethyl aluminum, triisopropyl aluminum, triisobutyl aluminum, trihexyl aluminum, tricyclohexyl aluminum, diethyl aluminum hydride, diisobutyl aluminum hydride, ethyl aluminum dihydride, isobutyl aluminum dihydride and the like. Particularly preferred are triethylaluminum, triisobutylaluminum, diethylaluminum hydride and diisobutylaluminium hydride. These may be a mixture of two or more kinds.

Examples of the halogen-containing Lewis acid compound which is the component (c) which constitutes the composite catalyst of the present invention include hydrides or organometallic halides of elements belonging to IIIb, IVb or Vb, preferably aluminum element, and the halides are chlorine or bromine. Is preferred. Examples of these compounds include:
Methyl aluminum dibromide, methyl aluminum dichloride, ethyl aluminum dibromide, ethyl aluminum dichloride, butyl aluminum dibromide, butyl aluminum dichloride, dimethyl aluminum bromide, dimethyl aluminum chloride, diethyl aluminum bromide, diethyl aluminum chloride, dibutyl aluminum bromide, dibutyl aluminum chloride , Methylaluminum sesquibromide, methylaluminum sesquibromide, ethylaluminum sesquibromide, ethylaluminum sesquichloride, dibutyltin dichloride, aluminum tribromide, antimony trichloride,
There are antimony pentachloride, phosphorus trichloride, phosphorus pentachloride and tin tetrachloride, and particularly preferred are diethyl aluminum chloride, ethyl aluminum sesquichloride,
Examples include ethyl aluminum dichloride, diethyl aluminum bromide, ethyl aluminum sesquibromide and ethyl aluminum dibromide.

The amount or composition ratio of each component of the composite catalyst used in the production method of the present invention varies depending on its purpose. Generally, the amount of the component (a) used is 0.01 to 10 mmol per 100 g of the conjugated gen monomer, preferably
It can be used in the range of 0.05 to 1 mmol. Further, generally, the amount of the component (b) used is represented by a molar ratio with respect to the component (a),
(B) / (a) = 1 to 100, preferably 5 to 50 can be used. Further, the molar amount of the component (c) used varies depending on the number of halogen atoms contained in the molecule, and is represented by the number of halogen atoms per 1 mol of the component (a), generally halogen atom / (a) = 1 to 6, It can be preferably used in the range of 2 to 4.

The monomer that can be used in the production method of the present invention can be selected from conjugated gen compounds having a carbon number of 4 to 8 such as butadiene, isoprene, piperylene, and dimethyl butadiene, or a mixture thereof. The mer is butadiene. It is also possible to polymerize or copolymerize with a vinyl aromatic compound in the presence of a vinyl aromatic hydrocarbon compound such as styrene.

The production method of the present invention is carried out by bulk polymerization or solution polymerization. As the polymerization solvent that can be used when the solution polymerization method is used, n-pentane, n-hexane, n-
Aliphatic hydrocarbons, alicyclic hydrocarbons or aromatic hydrocarbons having a boiling point of 200 ° C. or less such as heptane, cyclohexane, benzene and toluene are preferable. The polymerization solvent may of course be a mixture of these two components. It is also possible to include a small amount of halogenated hydrocarbons such as methylene chloride and chlorobenzene, and aprotic polar organic solvents such as ketone compounds, ether compounds and trialkylamine compounds. The solubility and thus the polymerization activity can be further improved.

The polymerization temperature in the production method of the present invention is -30 to 150 ° C,
It is preferably carried out at 10 to 120 ° C, particularly preferably at 30 to 100 ° C. The polymerization reaction type can be used in either a batch method or a continuous method.

It is also possible in the production method of the present invention to carry out a preliminary reaction or aging of some or all of the catalyst components in the presence or absence of the conjugated gen monomer prior to the polymerization. Depending on the conditions of these operations, the catalytic activity is improved, and further effects such as narrowing the molecular weight distribution of the obtained polymer can be achieved.

After the polymerization reaction reaches a predetermined polymerization rate, if necessary, a known terminal modifier or terminal branching agent, a polymerization terminator, and a polymer stabilizer are added to the reaction system to prepare a known conjugated gen polymer. The polymer can be recovered by the solvent removal and drying operations described in 1. above, such as steam stripping drying and heat drying.

The terminal modifier can be selected from various terminal modifiers known in the art of anionic polymerization of conjugated gens. Specific examples can be known from, for example, the following publicly known materials.

JP-A-62-149708 JP-A-62-156104 JP-A-62-161844 JP-A-63-3041 JP-A-62-22852 JP-A-62-22852 The terminal branching agent known in the anionic polymerization technology can be selected. Examples include multiepoxides, multiisocyanates, multiimines, multialdehydes, multiketones, multianhydrides, multiesters, monoesters, multihalides, carbon monoxide and carbon dioxide. Particularly preferred coupling agents are tetrachlorosilane, trichloromonomethylsilane, trichloromonoethylsilane,
They are multi-halogenated silicon compounds such as dichlorodiethylsilane, multi-halogenated tin compounds such as tetrachlorotin, trichloromonomethyltin and trichloromonoethyltin, and ester compounds such as diphenyl carbonate and diethyl adipate. The amount of the coupling agent used is considered to be optimum for maximum branching when the equivalent amount of the used organic metal is used. However, depending on the desired degree of coupling, any amount of coupling agent can be used. Generally, the amount of coupling agent is 0.1 to 1.5 equivalents per organoaluminum.
The coupling agent can be added alone or as an inert hydrocarbon solvent. Further, the coupling agent can be added at once, dividedly or continuously. Although the coupling reaction varies depending on its reactivity, it is usually carried out at a temperature close to the polymerization temperature for a few minutes to a few hours.

The polymerization terminator can be selected from water or a protic polar organic compound. Examples of the latter include various alcohols, phenols and carboxylic acid compounds.

The polymer stabilizer can be selected from known stabilizers for conjugated gen polymers and antioxidants.

Particularly preferred examples of stabilizers and antioxidants are 2,6-di-tert-butyl-4-methylphenol, tri-nonylphenyl phosphate, phenyl-β-naphthylamine, NN′-dialkyl-diphenylamine, N-alkyl- Examples thereof include diphenylamine.

The polymer obtained by the present invention is used for various applications utilizing its excellent rubber properties, for example, by mixing with other synthetic rubbers or natural rubbers as necessary, to treads, carcasses, sidewalls, bead portions, and other tire parts. Excellent performance by using, or industrial applications such as hoses, window frames, belts, anti-vibration rubbers, raw rubbers for automobile parts, etc., as well as impact-resistant polyethylene, resin reinforcing agents such as ABS resin, The effect can be achieved.

〔Example〕

The present invention will be specifically described below with reference to examples, but the scope of the present invention is not limited to these examples.

Examples 1 to 3 and Comparative Examples 1 to 3 (1) Preparation of Composite Salt Compound A rare earth metal corresponding to the general formula LnA ₁ B ₂ or LnA ₂ B ₁ which is the component (a) of the composite catalyst used in this example is prepared. The complex salt was prepared by the method shown below. Here, Ln is neodymium metal, A is an acid group of 2-ethylhexanoic acid, and B is p-.
It is an acid group of nonylphenol.

The complex salt is obtained by mixing an acetone solution of lanthanum chloride having a composition ratio corresponding to each composition and an acetone solution of a mixture of sodium salt of 2-ethylhexanoic acid and sodium salt of p-nonylphenol with stirring to react. , And then dried. The obtained complex salt can be subjected to component analysis by liquid chromatography using tetrahydrofuran as a developing solvent. These are neodymium salts of 2-ethylhexanoic acid and p- as impurities, respectively.
Neodymium salt of nonylphenol and non-targeted LnA ₁ B ₂
Alternatively, it partially contained a complex salt that reacts with LnA ₂ B ₁ .

The component purity of the obtained complex salt was 85% in the complex salt corresponding to LnA ₂ B ₁ and 88% in the complex salt corresponding to LnA ₁ B ₂ .

(2) Polymerization reaction A sufficiently dried 700 ml pressure-resistant glass bottle was capped and the inside was thoroughly purged with dry nitrogen. After injecting 400 g of cyclohexane mixed solution containing 60 g of 1,3-butadiene in a bottle, 2-ethylhexanoic acid and p-nonylphenol shown in Table 1 are used as ligands with the same composition shown in Table 1. 0.12 mmol of complex salt compound of neodymium, 3.6 mmol of triisobutylaluminum, and further ethylaluminum sesquichloride were added so as to have a Cl / Nd = 3 element ratio.
Polymerization was carried out at 5 ° C for 2 hours. After the polymerization, the reaction was stopped with 10 ml of a 10 wt% methanol / cyclohexane mixed solution of BHT [2,6-bis (t-butyl) -4-methylphenol], and the polymer was separated with a large amount of methanol at 50 ° C.
It was dried in vacuum.

Example 1 is a complex salt corresponding to LnA ₂ B ₁ obtained by the above-mentioned complex salt preparation, and Example 3 is a complex salt corresponding to LnA ₁ B ₂ .
Further, in Example 2, the both were used so as to be equimolar.

Comparative Examples 1 and 2 are examples in which the neodymium salt of 2-ethylhexanoic acid and the neodymium salt of p-nonylphenol were used alone. Comparative Example 3 is an example in which a neocym salt of 2-ethylhexanoic acid and a neodymium salt of p-nonylphenol were sequentially added in equimolar amounts so that the total amount was 0.12 mmol.

The yield, 1,4-cis content, molecular weight distribution and Mooney viscosity of the polymer thus obtained are shown in Table-1.

(3) Analytical method 1) The cis content was determined by measuring with an infrared spectrophotometer and processing the data by the Morello method.

2) The molecular weight distribution was analyzed by gel permeation chromatography using THF (tetrahydrofuran) as a developing solvent.

Examples 4 to 6 and Comparative Example 4 In Examples 4 to 5, other organic acids for forming a complex salt compound of neodymium with a carboxylic acid were used instead of p-nonylphenol. The same procedure as in Example 1 was repeated except that -di-sec-butylphenol, isoamyl alcohol and tert-dodecanethiol were used. Further, Comparative Example 3 was carried out in the same manner as in Example 1 except that dodecylbenzenesulfonic acid, which is an organic acid compound in which the acidity of other organic acid for constituting the complex salt compound exceeds the acidity of carboxylic acid, is used. did. The results are shown in Table-2.

Examples 7-9 In Examples 7-9, Table 3 was used instead of 2-ethylhexanoic acid.
The procedure of Example 1 was repeated except that the carboxylic acid compound described was used. The results are shown in Table-3.

Examples 10 to 12 Examples 10 to 12 were carried out in the same manner as in Example 1 except that the organoaluminum shown in Table 4 was used in place of triisobutylaluminum and the amount shown in the same table was used. The results are shown in Table-4.

Examples 13 to 15 Examples 13 to 15 were carried out in the same manner as in Example 1 except that the halogen-containing Lewis acid in Table 5 was used in place of ethylaluminum sesquichloride in the amounts shown in the table. The results are shown in Table-5.
Shown in.

EFFECT OF THE INVENTION The present invention is a method for producing a conjugated gen polymer having a high cis 1,4 bond content and a narrow molecular weight distribution and exhibiting excellent rubber properties with extremely high efficiency.

[Brief description of drawings]

FIG. 1 is a flow chart showing a reaction for obtaining a compound salt compound of a rare earth metal of the present invention. In the figure, Ln is a rare earth metal, A is an acid group of a carboxylic acid compound, and B is an acid group of an organic acid compound other than a carboxylic acid having a lower acidity than the corresponding carboxylic acid. Also, 1 is 1
2 shows 2 pieces.

Claims (1)

[Claims] 1. In bulk polymerization or solution polymerization of a conjugated gen in a hydrocarbon solvent, (a) a carboxylic acid compound of a rare earth metal and a complex salt compound with another organic acid compound are prepared in advance, and then the complex is prepared. A method for producing a conjugated gen polymer, which comprises allowing a composite catalyst comprising a salt compound, (b) an organoaluminum compound and (c) a halogen-containing Lewis acid compound to be present. Here, the complex salt compound with a carboxylic acid compound of a rare earth metal and another organic acid compound is represented by the general formula LnA ₁ B ₂ or LnA ₂ B ₁
Ln is a rare earth metal, A is an acid group of a carboxylic acid compound, and B is an acid group of an organic acid compound other than the carboxylic acid having a lower acidity than the corresponding carboxylic acid.