JPS6023406A - Preparation of polybutadiene - Google Patents

Abstract

PURPOSE:To obtain a polymer having a sharp molecular weight distribution and improved rubber elasticity, by carrying out a specific pre-reaction, polymerizing butadiene in the presence of a blended catalyst consisting of an organic phosphate compound of rate earth metal, an organoaluminum compound and a halogen-containing Lewis acid compound. CONSTITUTION:Firstly, (A) an organic phosphate compound of rare earth metal obtained by reacting an alkali metal salt of organic phosphate compound [e.g., bis(2-ethylhexyl)phosphate, etc.] with a chloride of rare earth metal (e.g., Nd, etc.) is pre-reacted with (B) an organoaluminum compound (e.g., triethylaluminum, etc.) and (C) a halogen element-containing Lewis acid compound (e.g., methylaluminum dibromide, etc.) at 0-100 deg.C for 0.01-10hr in the presence or absence of a butadiene monomer before they are added to the reaction system. The butadiene monomer is polymerized in the presence of the blended catalyst consisting of the components A, B, and C, having a molar ratio of the halogen element/the rare earth element of 2-6.

Description

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

Many methods for producing polybutadiene have been known, and in particular, polybutadiene obtained using a composite catalyst mainly composed of transition metal compounds such as nickel, cobalt, and titanium has a cis content of more than 90%, and is a high-cis polybutadiene. Great as a butadiene rubber, along with low-sis polybutadiene rubber using a lithium-based catalyst! It is industrially manufactured and widely used for various purposes.

As one of the methods for producing this high-cis polybutadiene, a composite catalyst whose main component is a rare earth metal compound, especially a cerium compound, is known, and the resulting y! Myributadiene is said to have superior adhesiveness compared to general 71 isis polybutadiene.

(Kautschuk und Gummi Kuns
tstoffe, Volume 2.2, page 193? However, due to the activity level of this type of catalyst, the rare earth compound that is the main component of the catalyst, or the entire polymerization catalyst system may not be completely dissolved in the polymerization solvent and may be heterogeneous. , was insufficient. Furthermore, the molecular weight distribution of the polybutadiene obtained was extremely broad, and the rubber elasticity was not particularly superior to other natural polynotadiene rubbers.

Various attempts have been made to improve the drawbacks of these composite catalysts mainly composed of rare earth metals. For example, a polymerization catalyst is preformed in the presence of a conjugated diolefin prior to polymerization,
and a method of aging and improving activity (Tokuko Sho'I'7-
/'7729), as the rare earth metal compound which is the main component of the catalyst, a method using a rare earth metal alcolade compound, especially a neodymium alcolade, or a method using a specific tertiary organic carboxylate of neodymium. Method for uniformity (JP-A-Sho S11.-qogqo No. 5)
S-6 Otsu No. 903) etc. are known. However, the improvement was still insufficient, and the development of a new catalyst was desired for industrialization.

On the other hand, Chinese researchers have been conducting many studies on the kinetics and reaction mechanism of diene polymerization using composite catalysts mainly composed of rare earth metal compounds, and various catalyst systems of this type are being investigated.

It has been shown that a composite catalyst based on a specified organophosphate of neodymium has relatively high activity in the polymerization of Imbren.

(Pyoc, China-US B11ateral
Symp, Polym, Chem, Phya.

/979. ,．． (Page 7g2 (Published in 1991)) The present inventors investigated the above-mentioned problems in the production of polybutadiene by focusing on this composite catalyst, and found that the activity of this composite catalyst itself for zutadiene polymerization is insufficient. However, it was discovered that when a catalyst is prepared under certain specified conditions, it becomes a composite catalyst with extremely high activity, which enables polymerization with a small amount of catalyst, and the resulting polybutadiene has an extremely sharp molecular weight distribution. This led to the present invention.

That is, the present invention, as shown in the claims,
When polymerizing butadiene monomer in the presence of a composite catalyst consisting of a rare earth metal organophosphate compound, an organoaluminium compound, and a halogen element-containing Lewis acid compound, (1) the ratio of halogen element/rare earth metal is as follows. .

Co-A (molar ratio) (2) Prior to addition of the halogen element-containing Lewis acid compound, an organic phosphoric acid compound of a rare earth metal and an organic aluminum compound are preliminarily reacted in the presence or absence of a butadiene monomer.

The present invention proposes a method for producing polybutadiene characterized by the following.

The main component constituting the composite catalyst of the present invention is an organic phosphate compound of a rare earth metal. The rare earth metals used are:
Preferred metals include cerium, lanthanum, praseodymium, neodymium, and gadolinium, and neodymium in particular is industrially easily and inexpensively available among these metals, and provides a catalyst with high polymerization activity. Yes, it is the most preferable one. 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 may contain catalyst components other than the above-mentioned rare earth metal organic phosphate compounds, such as rare earth metal carboxylate compounds, alcoholade compounds, phenolate compounds, etc.

Further, the 4Jll phosphoric acid compound, which is another component forming the rare earth metal organic phosphate compound of the present invention, is represented by the following general formulas (I) and (I[).

(1) (II) (Here, j, k, 1, m represent integers of 0 or more,
They may be the same or different.

Furthermore, R1-R4 represent a hydrogen atom, a hydrocarbon group, an aromatic hydrocarbon group, an alkoxy group, or an alkylphenoxy group, and R1, R2, and R
3 and R4 may be the same group or different groups. )'' The general formula (1) represents a trivalent organic phosphoric acid compound, and is generally named in the form of trivalent phosphoric acid having a parent structure and its mono- or diester.

Such preferred examples include dibutyl phosphate, dipendyl phosphate, dihexyl phosphate, diheptyl phosphate,
Dioctyl phosphate, bis(, Z-ethylhexyl) phosphate, bis(/-methylheptyl) phosphate, dilauryl phosphate, dioleyl phosphate, diphenyl phosphate, bis(p-7 nylphenyl) phosphate, bis(/-methylheptyl) phosphate, Polyethin glycol (p-nonylphenyl), phosphoric acid (butyl)
(,2-Ethylhexyl), (/-Methylhexyl) phosphate (2-1thylhexyl), (2-ethylhexyl) phosphate (p-nonylphenyl), -monozthylhexylphosphonate, 2, -ethylhexyl- hep-ethylhexyl phosphonate, hep-ethylhexyl phenylphosphonate, mono-p-nonylphenyl ethylhexylphosphonate, mono-p-nonylphenyl phosphonate, mono-p-methylhexyl phosphonate, mono-p-methylhexyl phosphonate Nonylphenyl, dibutylphosphinic acid, bis(2-ethylhexyl)phosphinic acid, bis(l-methylheptyl)phosphinic acid, dilaurylphosphinic acid, dioleylphosphinic acid, diphenylphosphinic acid, bis(p-nonylphenyl)phosphinic acid, Butyl(2-ethylhexyl)phosphinic acid, (niethylhexyl)(/-methylheptyl)phosphinic acid, (
Niethylhexyl)(p-nonylphenyl)phosphinic acid, butylphosphinic acid, niethylhexylphosphinic acid, /-methylhebutylphosphinic acid, oleylphosphinic acid, laurylphosphinic acid, phenylphosphinic acid, p-nonylphenylphosphinic acid, etc. Can be mentioned.

Further, as a preferable example of the trivalent organic phosphoric acid compound represented by the above general formula (I[), 3 exemplified in the above (1) is preferable.
Examples include compounds in which the parent structure of the organic phosphoric acid compound is each substituted with phosphorous acid.

The solubility in organic solvents of the rare earth metal organophosphate compounds formed by the organophosphate compounds represented by the above general formulas (1) and (11) is as follows:
and the number of polyoxyethin groups that are its adducts. Generally, if the molecular weight of the substituents R1 to R4 is too small, the solubility of the rare earth metal organophosphate compound in an organic solvent will decrease, and if the molecular weight is too large, the solubility will similarly decrease. I don't like it. However, when the substituents R1, . In the case of polyoxyethylene adducts, the oil solubility decreases as the amount of the adduct increases, which is not preferable. Furthermore, the solubility of the organic phosphate compound of the rare earth metal in an organic solvent varies depending on the type of organic solvent or additives such as a Lewis base, and it is difficult to determine its superiority or inferiority. Among the organic phosphoric acid compounds exemplified above, more preferable examples include bis(L-ethylhexyl) phosphate, bis(/-methylheptyl) phosphate, his(p-nonylphenyl) phosphate, Bis(polyethylene glyph-p-nonylphenyl), phosphoric acid(/
-methylheptyl)(,2-ethylhexyl), (,2-ethylhexyl)(p-nonylphenyl) phosphate, mono-ethylhexyl phosphonate, mono-p-nonylphenyl 2-ethylhexylphosphonate , his(+2-ethylhexyl)phosphine/acid, bis(/-methylhebutyl)phosphinic acid, bis<p-nonylphenyl)phosphine i, (,2-ethylhexyl)(/-methylheptyl)phosphinic acid, (,2 -ethylhexyl)(p-nonylphenyl)phosphinic acid #(
Particularly preferred examples include bis(-monoethylhexyl) phosphate, his(/-methylhebutyl) phosphate,
Examples include heptanoethylhexyl λ-ethylhexylphosphonic acid and bis(coethylhexyl)phosphinic acid. The rare earth metal organic phosphate compound of the present invention can be easily obtained, for example, by reacting the alkali metal salt of these organic phosphate compounds with the above-mentioned rare earth metal chloride.

The first component constituting the composite catalyst of the present invention is an organoaluminum compound and is represented by the general formula (jl).

AlB2-HHn 伽) (where n is 0./or -, R5 is a hydrocarbon group having 1 to 3 carbon atoms) (is a hydrogen atom) Preferred organoaluminum compounds include trimethylaluminum, Examples include triethylaluminum, triisopropylaluminum, triimbutylaluminum, trihexylaluminum, tricyclohexylaluminum, diethylaluminum hydride, diisobutylaluminum hydride, ethylaluminum sibide, isobutylaluminum sibide, etc., and particularly preferred triethylaluminum, triisobutylaluminum, and These are inbutylaluminum, diethylaluminum hydride, and diimbutylaluminum hydride.

These may be a mixture of these or more types.

The third component constituting the composite catalyst of the present invention is a halogen element-containing Lewis acid compound. Preferred examples of these include halides or organometallic halides of elements belonging to main groups 1a, 1a, or Va of the periodic table, and the -ride is preferably chlorine or bromine. Examples of these compounds include methylaluminum dichloride, methylaluminum dichloride, ethylaluminum dichloride, ethylaluminum dichloride,
Butylaluminum dibumite, methylaluminum dichloride, dimethylaluminum bromide, dimethylaluminum chloride, diethylaluminum 7
p-mite, diethylaluminum chloride, diethylaluminum chloride, diptylaluminum chloride, methylaluminum sesquibromide, methylaluminum sesquichloride, ethylaluminum sesquichloride, ethylaluminum sesquichloride,
Diptyltin dichloride, aluminum tribromide, antimony trichloride, antimony pentachloride, phosphorus trichloride,
Among these are phosphorus pentachloride and tin tetrachloride, and particularly preferred are diethylaluminum chloride, ethylaluminum sesquichloride, ethylaluminum dichloride, diethylaluminum furomite, ethylaluminum sesquibromide and hethylaluminum dinoromide.

The composite catalyst of the present invention has extremely high activity, and the amount of catalyst used is preferably θ5xlo-3 mol or less expressed in rare earth metal per 100 r of butadiene monomer to be polymerized, and a particularly preferable range is 0.0/! i~0.3, X/0
-3 moles. Use beyond this is unnecessary for the present invention, and the use of unnecessary catalysts not only increases the amount of catalyst such as rare earth metals remaining in the polybutadiene, but is also unfavorable from an economic point of view.

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 polybutadiene can be made unnecessary. Further, the preferable composition ratio of the three catalyst components of the present invention, expressed as rare earth metal/aluminum/halogen element, is preferably //2 to 10O/2 to 6, particularly preferably //! ;-40/Y5N, 11-. Outside this range, it will not be possible to obtain polybutadiene with high activity and a sharp molecular weight distribution, which is the objective of the present invention.

In the present invention, the composite catalyst is prepared by pre-reacting a rare earth metal organophosphate and an organoaluminum compound or an organoaluminum hydride compound in the presence or absence of a butadiene monomer prior to the addition of a halogen element-containing Lewis acid. I need.

This preliminary reaction is preferably carried out at a reaction temperature of θ to 100°C. At temperatures below this, the preliminary reaction is insufficient;
On the other hand, temperatures exceeding 10θ°C are unfavorable because the molecular weight distribution expands. Particularly preferred reaction temperature is 20°C to gO
It is ℃. Further, the reaction time is required to be in the range of 0.0/~70 hours.

If the reaction time is shorter than this, the preliminary reaction will be insufficient and it will not be possible to obtain polybutadiene with high activity and a sharp molecular weight distribution, which is the objective of the present invention.On the other hand, if the reaction time is longer than this, the polymerization activity will actually decrease, which is preferable. It's not something.

A particularly preferred reaction time is 3 hours.

The catalyst component of the present invention must be prepared through the above-mentioned preliminary reaction, but if necessary, it may be aged in the presence of some butadiene monomers prior to polymerization. The reaction conditions for this ripening are butadiene monomer/
It is preferable to conduct the reaction at a rare earth metal ratio (molar ratio) of /~1000. If the molar ratio is lower than this, the effect of improving the polymerization activity by aging will be small, and conversely, the molecular weight distribution of the obtained liptadiene will become broader. On the other hand, a molar ratio higher than this is unnecessary and moreover becomes difficult because the temperature during ripening causes rapid polymerization of the butadiene monomer. A particularly preferred molar ratio is
It is O. In addition, the aging temperature was ONlθθ℃, and the aging time was 0.
．． 0/~2'1 hour is preferred. Outside this range, the effects brought about by aging will be small, or side effects such as broadening of the molecular weight distribution of the resulting polybutadiene will occur. Particularly preferred aging temperature is so-go°C and aging time is 0.0! ;-5 hours.

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 solvent used is n-
Aliphatic or alicyclic hydrocarbons such as pencun, n-hexane, n-hebutane, hexane, hexane, aromatic hydrocarbons such as benzene and toluene, or methylene chloride,
Halogenated hydrocarbons such as rubenzene are preferred. These may be a mixture of three or more types, or may contain a small amount of impurities. In addition, the polymerization temperature is -3θ℃~
/! It is carried out at 0°C, preferably 10 to 10°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 polybutadiene are performed.

The polybutadiene polymerized by the method of the present invention contains small amounts of other copolymerizable monomer components, such as isoprene,
It may also contain 3-pentadiene or the like.

Polybutadiene, which can be obtained extremely efficiently by the method of the present invention, has a sharp molecular weight distribution and is a raw material rubber that exhibits extremely excellent rubber elasticity. Taking advantage of this property, it can be used alone or blended with other diene rubbers or synthetic rubbers to produce tires such as l/red, carcass, sidewalls, beads, industrial products such as hoses, window frames, belts, anti-vibration rubber, and automobile parts. Used as raw material for rubber. It is also used as a toughening agent for impact-resistant polystyrene/ABS resins, etc.

Examples will be described below, and the rare earth metals used in the examples have a purity of 99.9% unless otherwise specified. In addition, when ethylaluminum sesquichloride is used as the p-gen element-containing Lewis acid, the structural formula AI Et□, 5''1.5 represents 1 mole.

Example 1 A sufficiently dried 700-pressure glass bottle was capped, and the inside was further purged with dry nitrogen for 3 hours. 101/, 3
- After sealing the lIOθ2n-hexane mixture containing butadiene in a bottle, neodymium aluminum phosphate 36
A pre-reaction was carried out for a certain period of time while maintaining the predetermined temperature in a water bath. Furthermore, 0.2 g mmol of ethylaluminum sesquichloride was added,
Polymerization was carried out at 6°C for 1 hour. After polymerization, BHT C
The reaction was stopped with a 10% methanol solution of 2,1,-bis(t-butyl)-coumethylphenol, and the polymer was precipitated and separated with a large amount of methanol, followed by vacuum drying at SO℃. did. Table 1 shows the conversion rate, Mooney viscosity, molecular weight distribution, and Miku p structure of the polymer thus obtained.

From Table 1, it is clear that if a pre-reaction is not performed, high polymerization activity cannot be obtained and the molecular weight distribution of the polymer will be very wide. It can be seen that a polymer with a narrow molecular weight distribution can be obtained.

Example λ In the same manner as in Example 1, a cyclohexane mixture of 601/3001 containing 3-butadiene was used in a 700-pressure glass bottle to prepare Nd(P2)3 as a neodymium organophosphate compound. C However, for P2, after adding a predetermined amount of diisobutylaluminum hydride and carrying out a preliminary reaction at 23°C for /j minutes, adding a predetermined amount of ethylaluminum sesquicluride and polymerizing at SO°C for 2 hours. I did it. The polymerization results are shown in Table 2.

(Left space below) From Table 1, it can be seen that the catalyst has high activity only when the molar ratio of chlorine atoms to neodymium atoms is within a limited range, and even when the amount of catalyst is small, it has excellent activity within this range. It is also found that it has a certain activity.

Example 3 Various neodymium organophosphate compounds θ72 as catalysts
mmol, organoaluminum or organoaluminum hydride compound, 1 mmol, 0 of hap/r'n atoms
．． A Lewis acid containing a hapogen element containing 12 mmol was used. The preliminary reaction was carried out at 2S° C. for 7.1 minutes, and the monomer mixture and polymerization conditions used were the same as in Example. The polymerization results are shown in Table 3.

(The following is a blank space) From Table 3, it can be seen that all of the rare earth metal organic phosphates of the present invention have extremely excellent polymerization activity as a catalyst.

In Example No. 22, a /θO-pressure-resistant glass bottle was capped after being sufficiently purged with dry nitrogen, and a mixture of l,3-butadiene and 20 cyclohexane was added with a mixture of λ72 and lamb hydride.
After adding 259 mol and carrying out a preliminary reaction for Ik minutes at 1.23°C, 03 mmol of ethylalumium sesquichloride was added and aging was carried out at 23°C for 3 hours. The aged catalyst thus obtained was added to a cyclohexane mixture of 60 tons and 3009 containing 3-butadiene in a 'toomp' pressure-resistant glass bottle, and co-polymerized at 50°C.

In experiment number 23, Nd(Pz
), 1 tq2 of 3-butadiene: 1Q% cyclohexane mixture, /, -mmol of diimbutylaluminum hydride 0. /A mmol of ethyl aluminum sesquid was used to age the catalyst.
Polymerization was carried out under the same conditions and operations as in Experiment No. 1. In addition, in Comparative Example 5, when the catalyst was aged and used without performing the preliminary reaction in Experiment No.--, in Comparative Example 6, the same reaction occurred.
This is an example in which neither of these steps is performed. The above polymerization results are summarized in Table 1.

(The following is a blank space) From Table 7, it can be seen that by aging the catalyst, the polymerization activity is further increased compared to the case where aging is not performed (experiment number g, 9). However, even when aging is performed, if no preliminary reaction is performed prior to aging (Comparative Example S), neither satisfactory polymerization activity nor molecular weight distribution can be obtained; furthermore, when both are omitted (
Comparative Example 6 and Comparative Example 1), the effects of the present invention cannot be exhibited at all. That is, it can be seen that in order to exhibit the effects of the present invention, it is essential to perform at least a preliminary reaction of the catalyst.

Example S The types and amounts of the rare earth metal salt compound of the organophosphoric acid compound and the organoaluminum compound were changed, and 0.2 g mmol of ethylaluminum sesquichloride (θll/mmol for experiment number 3θ) was used at HO℃.
Polymerization was carried out for several hours. A cyclohexane mixture 3001 containing 3-butadiene 601 was used as a monomer. The preliminary reaction was carried out at 23° C. for 73 minutes, and the catalyst was aged at 23° C. for 3 hours in a molar amount of 70 times the amount of bookdiene used and the amount of rare earth metal. The experimental method was the same as in the previous experiment. IB match result 8th
Show the table below.

(The following is a blank space) From Table 3, it can be seen that even if a slightly low-purity product of neodymium metal is used as a catalyst, there is virtually no difference in the effect from when a high-purity product is used.

Furthermore, it is clear that even when praseodymium or gadolinium is used as the rare earth metal, the effects of the present invention are very excellent.

Example 6 Among the catalyst components, a binary mixed system was used as the organic ring of rare earth metal. That is, a neodymium organic phosphate compound was used as the catalyst component (I), and a neodymium salt compound other than organic phosphoric acid was used as the catalyst component (■), to form a mixed system of both. Other catalyst and monomer conditions, as well as polymerization conditions, were as follows:
Same as Example/. The polymerization results are shown in Table 6.

(Left below) From Table 6, we can see that the higher the mixing ratio of the neodymium organic phosphate compound, the higher the polymerization activity. It can be seen that the molecular weight distribution becomes higher and the molecular weight distribution becomes narrower. In particular, when the mixing ratio of the organic phosphate compound of neodyno is high, it is clear that even in a combined catalyst component system such as honjitsu iron, it has very excellent polymerization activity.

Patent applicant: Asahi Kasei Industries, Ltd. Representative Patent Attorney Toru Ashino

Claims (4)

[Claims] (1) When polymerizing butadiene monomer in the presence of a composite catalyst consisting of a rare earth metal organophosphate compound, an organoaluminium compound, and a halogen element-containing Lewis acid compound, the halogen element/rare earth metal ratio is as follows: Dea col 6 (
molar ratio) ■ A method for producing polybutadiene, which comprises preliminarily reacting an organophosphoric acid compound of a rare earth metal and an organoaluminum compound in the presence or absence of a butadiene monomer prior to adding a halogen element-containing Lewis acid compound. . (2), the preliminary reaction conditions are Temperature: 0-700℃ ■Time: o, oi ~ 10 hours The manufacturing method according to claim 1. (3) The production method according to claim 1 or 2, characterized in that the catalyst components are aged in the presence of some butadiene monomers prior to polymerization. (4), the ripening conditions are such that the ratio of butadiene monomer/rare earth metal is /~iooθ(
Molar ratio) (1) Temperature: 0 to 700°C, 0 hours: 0.0/ to 21 hours. The manufacturing method according to claim 3.