JPH0551607B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for efficiently producing a conjugated diene polymer having a sharp molecular weight distribution and excellent rubber elasticity.

Many methods for producing conjugated diene polymers have been known, and in particular, conjugated diene polymers obtained using composite catalysts whose main components are transition metal compounds such as nickel, cobalt, and titanium have a cis content of over 90%. It is industrially produced in large quantities as high-cis polybutadiene rubber, high-cis isoprene rubber, etc. together with low-cis type rubbers using lithium-based catalysts, and is widely used for various purposes.

As one of the methods for producing this high-cis type conjugated diene polymer, a composite catalyst containing a rare earth metal compound, especially a cerium compound as a main component, is known. It is said to have superior adhesiveness compared to coalescing. (Kautschuk und Gummi
(Kunststoffe, Vol. 22, p. 293, published in 1969) However, the activity of this type of catalyst is heterogeneous because the rare earth metal compound, which is the main component of the catalyst, or the entire polymerization catalyst is not completely dissolved in the polymerization solvent. Sometimes,
It was inadequate. Further, the molecular weight distribution of the obtained conjugated diene polymer was extremely broad, and the rubber elasticity was not particularly superior to other high-cis conjugated diene polymers.

Various attempts have been made to improve the shortcomings of these composite catalysts containing rare earth metals as main components. (Japanese Patent Publication No. 47-14729), a method using a rare earth metal alcoholate compound, especially neodymium alcoholate, as the rare earth metal compound that is the main component of the catalyst, a method using a certain specified tertiary organic carboxylic acid of neodymium. A method of making the catalyst homogeneous using salt (Japanese Patent Application Laid-open Nos. 54-40890 and 55-66903), a composite catalyst whose main component is a specified organic phosphate of neodymium (Pyoc.China-US Bilateral Symp. Polym.
Chem.Phys.19779, page 382 (published in 1981), etc. are known. However, the improvement was still insufficient, and the development of a new catalyst was desired for industrialization.

In order to solve the above-mentioned problems in the production of conjugated diene polymers, the present inventors have conducted studies focusing on the type of rare earth metal compound that constitutes this composite catalyst, and have developed a combination of rosin acids and salts of rare earth metals. Not only is it easy to prepare and has excellent solubility, but it also provides an extremely active composite catalyst, allowing polymerization with a small amount of catalyst, and the resulting conjugated diene polymer has an extremely sharp molecular weight distribution. The present invention was based on this discovery.

That is, as shown in ^the claims, the present invention has ^the following _formula : (B) A rare earth metal rosin acid ^salt represented by rosin acid or an organic acid group obtained by hydrogenation ^reaction or ^{disproportionation} reaction of rosin acid. ² , R ³ and R ⁴ are each the same or different and are hydrogen or a hydrocarbon group having 1 to 10 carbon atoms, and are not all hydrogen), and (C) periodic table Production of a conjugated diene polymer characterized by polymerizing a conjugated diene monomer in the presence of a catalyst consisting of a halogen element-containing Lewis acid compound selected from halides of elements belonging to main group a or a or organometallic halides of It is about the method.

The main component constituting the composite catalyst of the present invention is a rare earth metal rosin acid salt compound. Examples of the rare earth metals used include cerium, lanthanum, praseodymium, neodymium, gadolinium, and didymium. Among these metals, neodymium is industrially easily and inexpensively available, and it is also used as a catalyst with high polymerization activity. This is the most preferable option. The rare earth metal of the present invention may be a mixture of two or more of these metals, or may contain a small amount of other rare earth metals or metals other than rare earth metals. Furthermore, the composite catalyst of the present invention contains catalyst components other than the above-mentioned rare earth metal rosin acid salt compound,
For example, it may contain rare earth metal carboxylate compounds, phosphate compounds, alcoholate compounds, phenolate compounds, and the like.

Further, the main component of the rosin acid compound, which is another component forming the rare earth metal rosin acid salt compound of the present invention, is represented by the following general formula.

(In the formula, the carbon-carbon bond represents a saturated single bond or an unsaturated double bond.

Examples include abietic acid, dehydrogenated abietic acid, dihydroabietic acid, tetrahydroabietic acid, and the like. These are rosin acids or rosin acid compounds obtained by hydrogenation reaction or disproportionation reaction of rosin acids.

The second component constituting the composite catalyst of the present invention is an organoaluminum compound, and is represented by the following general formula.

AlR ²・R ³・R ⁴ (in the formula, R ² , R ³ and R ⁴ are hydrogen or have 1 to 1 carbon atoms)
10 hydrocarbon groups, not all of which are hydrogen. ) Preferred organic aluminum compounds include trimethylaluminum, triethylaluminum, triisopropylaluminum, triisobutylaluminum, trihexylaluminum,
Examples include tricyclohexylaluminum, diethylaluminum hydride, diisobutylaluminum hydride, ethylaluminum dihydride, isobutylaluminum dihydride, and particularly preferred are triethylaluminum, triisobutylaluminum, diethylaluminum hydride, and diisobutylaluminum hydride. This may be a mixture of two or more types.

The third component constituting the composite catalyst of the present invention is a halogen element-containing Lewis acid compound selected from halides of elements belonging to main group a or a of the periodic table or organometallic halides. Further, as the halide, chlorine or bromine is preferable. Examples of these compounds are dibutyltin dichloride, silicon tetrachloride, antimony trichloride, antimony pentachloride, phosphorus trichloride, phosphorus pentachloride and tin tetrachloride.

The composite catalyst of the present invention has extremely high activity, and the amount of catalyst used is preferably 0.5 x 10 ^-3 mol or less expressed as rare earth metal per 100 g of conjugated diene monomer to be polymerized, and a particularly preferable range is 0.015 to 0.3 ×10 ^-3
It is a mole. Use beyond this is unnecessary for the present invention, and the use of unnecessary catalysts not only increases catalyst residues such as rare earth metals remaining in the conjugated diene polymer, but is also preferable from an economic standpoint. Not. In the production method of the present invention, the amount of catalyst used is extremely small as described above, and in some cases, a so-called deashing step for removing catalyst residue from the conjugated diene polymer can be made unnecessary. Further, the preferable composition ratio of the three catalyst components of the present invention is expressed as rare earth metal/aluminum/halogen element, and is 1/1.
The ratio is preferably 2 to 100/2 to 6, particularly preferably 1/5 to 50/2.5 to 5. Outside this range, it is difficult to obtain a highly active conjugated diene polymer with a sharp molecular weight distribution.

In the present invention, as shown in Figure 1, the composite catalyst pre-reacts a rare earth metal rosinate and an organoaluminum compound in the presence or absence of a conjugated diene monomer prior to the addition of a halogen-containing Lewis acid compound. It is preferable to let This preliminary reaction is carried out at 0 to 100°C for a reaction time of 1 minute to 10 hours. The preliminary reaction conditions are preferably carried out at a conjugated diene/rare earth metal ratio (molar ratio) of 0 to 1000.

The polymerization in the present invention can be carried out without a solvent or in the presence of a solvent. In the latter case, the solvents used include aliphatic or alicyclic hydrocarbons such as n-pentane, n-hexane, n-heptane, and cyclohexane, aromatic hydrocarbons such as benzene and toluene, or methylene chloride and chlorobenzene. Preferred are halogenated hydrocarbons such as. These may be a mixture of two or more types, or may contain a small amount of impurities. Also, the polymerization temperature is -30℃
It is carried out at ~150°C, preferably 10-120°C. Furthermore, the polymerization reaction format may be either a batch method or a continuous method.

After the polymerization reaction reaches a predetermined polymerization rate, a known polymerization terminator is added to the reaction system to terminate the reaction, and the usual steps of solvent removal and drying in the production of conjugated diene polymers are performed.

Conjugated diene monomers polymerized by the method of the present invention include, for example, 1,3-butadiene, isoprene,
1,3-pentadiene and the like. Moreover, a mixture of these conjugated dienes may be used.

The conjugated diene polymer obtained extremely efficiently by the method of the present invention has a sharp molecular weight distribution and is a raw material rubber exhibiting extremely excellent rubber elasticity. Taking advantage of this property, it can be used alone or blended with other diene rubbers or synthetic rubbers to make tires, hoses, etc., such as treads, carcass, sidewalls, beads, etc.
It is used as raw material rubber for industrial products such as window frames, belts, anti-vibration rubber, and automobile parts. It is also used as a toughening agent for high-impact polystyrene, ABS resin, etc.

Examples are described below. Unless otherwise specified, rare earth metals used in the examples have purity.
It is 99.9% of the time. In addition, when ethylaluminum sesquichloride is used, the structural formula is AlEt _1.5
Cl _1.5 represents 1 mole.

Reference Examples 1 to 4 and Comparative Examples 1 to 3 Sufficiently dried 700 ml pressure-resistant glass bottles were capped and the inside was purged with dry nitrogen for 3 hours. After sealing 400 g of n-hexane mixture containing 60 g of 1,3-butadiene in a bottle, 0.12 mmol of neodymium rosinate or various organic acid salts and 3.6 mmol of triisobutylaluminum were added, and the mixture was heated in a water bath for 23 hours. Preliminary reaction was carried out for 15 minutes while maintaining the temperature at °C. Further, 0.28 mmol of ethylaluminum sesquichloride was added, and polymerization was carried out at 65°C for 1 hour. After polymerization, BHT [2,6-bis(t
The reaction was stopped with 10 ml of a 10% methanol solution of (butyl)-4-methylphenol, and the polymer was precipitated and separated with a large amount of methanol, followed by vacuum drying at 50°C. Table 1 shows the conversion rate, Mooney viscosity, molecular weight distribution, and microstructure of the polymer thus obtained.

Reference Examples 5 to 10 Performed in the same manner as Reference Examples 1 to 4, using 0.12 rosin acid salts of rare earth metals shown in Table 2 as composite catalysts.
mmol, triisobutylaluminum 3.6 mmol and ethylaluminum sesquichloride
0.28 mmol was used. Table 2 shows the conversion rate, Mooney viscosity, molecular weight distribution and microstructure of the obtained polymer.

Reference Examples 11 to 17 The same method as in Reference Examples 1 to 4 was carried out, using 0.12 mmol of neodymium rosinate, 3.6 mmol of the organoaluminum compound shown in Table 3, and 0.28 mmol of ethylaluminum sesquichloride as a composite catalyst. Table 3 shows the conversion rate, Mooney viscosity, molecular weight distribution and microstructure of the obtained polymer.

Reference Examples 18 to 25 and Examples 1 to 3 Performed in the same manner as in Reference Examples 1 to 4, using 0.12 mmol of neodymium rosinate, 3.6 mmol of triisobutylaluminum and the halogen element-containing Lewis acid compound shown in Table 4 as a composite catalyst. The amount of halogen atoms contained was 0.36 mmol. Table 4 shows the conversion rate, Mooney viscosity, molecular weight distribution and microstructure of the obtained polymer.

Reference Examples 26 to 29 The same method as in Reference Examples 1 to 4 was carried out, using 0.12 mmol of neodymium rosinate, 3.6 mmol of triisobutylaluminum, and 0.28 mmol of ethylaluminum sesquichloride as the composite catalyst. As the solvent during polymerization, the solvents shown in Table 5 were used instead of n-hexane. The conversion rate of the obtained polymer,
Mooney viscosity, molecular weight distribution and Mislo structure are shown in Table 5.

Reference Example 30 A sufficiently dried 700 ml pressure-resistant glass bottle was capped, and the inside was purged with dry nitrogen for 3 hours. 60g
After sealing 300 g of n-hexane mixture containing 1,3-butadiene in a bottle, 0.12 mmol of neodymium rosinate and triisobutylaluminum.
3.6 mmol and 0.28 mmol of ethylaluminum sesquichloride were successively added, and polymerization was carried out at 65° C. for 1 hour. After polymerization, the polymer solution was treated in the same manner as in Reference Examples 1 to 4. Table 6 shows the conversion rate, Mooney viscosity, molecular weight distribution and microstructure of the obtained polymer.

Reference Example 31 A sufficiently dried 100 ml pressure-resistant glass bottle was capped, and the inside was purged with dry nitrogen for 3 hours. 1,
20% by weight solution of 3-butadiene in n-hexane 2.27
Collect g in a bottle and add neodymium rosin acid.
0.12 mmol diisobutylaluminum hydride and 0.32 mmol ethylaluminum sesquichloride were added sequentially at 23 °C.
Preliminary reaction was performed for 15 minutes. The aged catalyst thus obtained was added to a mixed solution of 300 g of n-hexane containing 60 g of 1,3-butadiene in a 700 ml pressure bottle, and polymerization was carried out at 65° C. for 1 hour. Table 6 shows the conversion rate, Mooney viscosity, molecular weight distribution and microstructure of the obtained polymer.

Reference Example 32 Performed in the same manner as Reference Examples 1 to 4, using 400 g of n containing 60 g of isoprene as a monomer mixture.
0.12 mmol of neodymium rosinate, 3.6 mmol of triisobutylaluminum, and 0.28 mmol of ethylaluminum sesquichloride were used as a composite catalyst. Table 7 shows the conversion rate, Mooney viscosity, molecular weight distribution and microstructure of the obtained polymer.

[Brief explanation of drawings]

Figure 1 is a diagram of a preferred catalyst preparation process.

[Table] Values measured.
*2) Value measured using Morello's method using an infrared spectrophotometer.

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【table】

【table】

[Table] Measured values.
*2) Value measured using Morello's method using an infrared spectrophotometer.

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Claims (1)

[Claims] 1 (A) General formula Ln-(OCOR ¹ ) ₃ (wherein Ln is neodymium, lanthanum, cerium,
These are praseodymium, samarium, gadolinium, and didymium, and -OCOR ¹ represents rosin acid or an organic acid group obtained by hydrogenation reaction or disproportionation reaction of rosin acid. ) Rare earth metal rosin acid salts represented by (B) general formula AlR ²・R ³・R ⁴ (wherein R ² , R ³ and R ⁴ are each the same or different, hydrogen or carbon number 1 to (10 hydrocarbon groups, not all of which are hydrogen); and (C) a halogen element selected from halides or organometallic halides of elements belonging to main group a or a of the periodic table. 1. A method for producing a conjugated diene polymer, which comprises polymerizing a conjugated diene monomer in the presence of a catalyst made of a Lewis acid compound. 2. Claim 1, characterized in that the catalyst component (A) and the catalyst component (B) are pre-reacted in the presence or absence of a conjugated diene monomer prior to the addition of the catalyst component (C). A method for producing a conjugated diene polymer. 3. The method for producing a conjugated diene polymer according to claim 1 or 2, characterized in that the catalyst components are aged in the presence of some conjugated diene monomers prior to polymerization. 4. The method for producing a conjugated diene polymer according to claim 1, 2 or 3, wherein the conjugated diene monomer is 1,3 butadiene.