JP2566889C - - Google Patents

Description

The present invention relates to a method for producing an olefin-based polymer or a styrene-based polymer, and more particularly, to a method for polymerizing an olefin or styrene by using a specific catalyst. The present invention relates to a method for efficiently producing an olefin polymer or a styrene polymer (especially a syndiotactic structure) with improved activity. [Problems to be Solved by the Prior Art and the Invention] Conventionally, in producing an olefin-based polymer or a styrene-based polymer by polymerizing olefin or styrene in the presence of a catalyst, (A) a transition metal compound and (B) A method using an aluminoxane is widely known (JP-A-58-19309, JP-A-59-95292, JP-A-60-135408, JP-A-61-31404, etc.). The aluminoxane used in these conventional methods is obtained by reacting trialkylaluminum (AlR ₃ ) with water of crystallization such as copper sulfate pentahydrate (CuSO ₄ .5H ₂ O). Is the general formula In units of Aluminoxane of the general formula Is a cyclic aluminoxane. Here, R in the formula is an alkyl group having 1 to 6 carbon atoms, and p is an integer of 0 to 100. However, when using such a chain or cyclic aluminoxane,
Although it has olefin or styrene polymerization activity, it cannot be said to have sufficiently high activity. [Means for Solving the Problems] As a result of repeated studies on an efficient production method of an olefin polymer or a styrene polymer having a syndiotactic structure, the present inventors found that a transition metal compound and an aluminoxane were mainly used. It has been found that, when polymerizing olefin or styrene with a catalyst as a component, the use of a specific transition metal compound and the use of methylaluminoxane having a partially crosslinked structure significantly improve the catalytic activity. The present invention has been completed based on such findings. That is, the present invention provides a method for producing an olefin polymer or a styrene polymer by polymerizing an olefin or styrene or a derivative thereof in the presence of a catalyst comprising (A) a transition metal compound and (B) an aluminoxane. A) a cyclopentadienyl compound containing any one of titanium, zirconium and hafnium as the transition metal compound, and (B) an aluminoxane represented by the general formula: And a repeating unit represented by [Wherein, m and n are each an integer of 1 or more. Production of an olefin-based polymer or a styrene-based polymer having two repeating units represented by the following formula, and using a methylaluminoxane having a molecular weight of 200 to 2,000 according to a freezing point depression method of benzene. It provides a method. As described above, the method of the present invention comprises (B) an aluminoxane having two repeating units of a repeating unit represented by the general formula [I] and a repeating unit represented by the general formula [II]; It is characterized by using methylaluminoxane having a molecular weight of 200 to 2,000 according to a freezing point depression method. Such an aluminoxane of the present invention has a molecular weight of 200 to 2,000, preferably 500 to 1,000, as measured by the freezing point depression method of benzene. The aluminoxane used as the component (B) in the present invention can be obtained by adding trimethylaluminum to water and reacting the same, but instead of controlling the ratio of water to trimethylaluminum, the amount of alkane actually generated is controlled. Can be obtained. That is, the alkane (RH) actually generated is 2.05 to 2.50 mol per mol of trimethylaluminum as a raw material,
Preferably, the reaction is stopped at a point of 2.1 to 2.4 mol to have two repeating units of the above-mentioned general formula (I) and the general formula (II). Having a molecular weight of 200 based on the freezing point depression method of benzene.
Methylaluminoxane of ~ 2000 can be obtained. If the amount of this alkane is suppressed to less than 2 mol, a crosslinked structure cannot be obtained,
In addition, it is not preferable to carry out the reaction until the amount exceeds 2.5 moles, since gelation due to excessive crosslinking results in insolubility. Further, conventional water as water added to the trimethylaluminum, solvent saturated water, water adsorbed or CuSO ₄ · 5H ₂ O of _{inorganic, Al 2 (SO 4) 3} · 14~18 H 2 O, MgSO 4 · 7
H ₂ O, such as a metal salt containing crystal water such as MgCl ₂ · 6 H ₂ O is used. The reaction solvent includes an inert hydrocarbon such as an aliphatic hydrocarbon such as hexane, heptane, and decane, and an aromatic hydrocarbon such as benzene, toluene, and xylene, and preferably benzene and toluene. Further, the reaction temperature is 0 ° C to 50 ° C, preferably 0 ° C to 45 ° C. The reaction time is arbitrary and varies depending on the reaction temperature, but it takes 70 hours or more when the reaction temperature is 20 ° C, whereas it takes 24 hours when the reaction temperature is 40 ° C, and the methylaluminoxane having a partially cross-linked structure Can be manufactured. Next, in the method of the present invention, as the transition metal compound used as the component (A), a cyclopentadienyl compound containing any one of titanium, zirconium and hafnium is used. May be appropriately selected according to the requirements. For example, when an olefin polymer is produced, the general formula (CP) MR ³ R ⁴ R ⁵ ... [IV] [wherein CP represents a cyclopentadienyl group, and M represents any of titanium, zirconium and hafnium. One of R ³ , R ⁴ and R ⁵ represents an alkyl group having 1 to 6 carbon atoms, a cyclopentadienyl group, a halogen atom or a hydrogen atom. It is preferable to use a compound represented by the following formula: Examples of the cyclopentadienyl compound represented by the general formula [IV] include dihalides such as bis (cyclopentadienyl) zirconium dichloride, bis (cyclopentadienyl) titanium dichloride, and bis (cyclopentadienyl) hafnium dichloride. And halide hydrides such as bis (cyclopentadienyl) zirconium monochloride hydride and bis (cyclopentadienyl) titanium monochloride hydride. In the case of producing a styrene-based polymer, particularly a styrene-based polymer having a syndiotactic structure, the general formula TiR ⁶ _a R ⁷ _b R ⁸ _c X _{4- (a + b + c)} ... [V] or TiR ⁶ _b R ⁷ _e X _{3- (d + e)} ... [VI] [wherein R ⁶ , R ⁷ and R ⁸ are each hydrogen, having 1 to 20 carbon atoms, preferably 1 to 1
An alkyl group having 0, an aryl group having 6 to 20, preferably 6 to 10 carbon atoms, an alkylaryl group, an arylalkyl group, an acyloxy group having 1 to 20 carbon atoms, preferably 1 to 10 carbon atoms, a cyclopentadienyl group, Represents a substituted cyclopentadienyl group or an indenyl group having a number of 5 to 20, preferably 5 to 10, and X represents a halogen. a, b
, C each represent an integer of 0 to 4, and d and e each represent an integer of 0 to 3. At least one compound selected from the group consisting of titanium compounds and titanium chelate compounds represented by the following formulas, for example, methyl titanium trichloride, titanium terra methoxide, titanium terra ethoxide, titanium monoisopropoxy trichloride, titanium diisopropoxy monochrome Ride, tetra (2-ethylhexyloxy) titanium, cyclopentadienyltitanium trichloride, titanium tetrachloride, titanium tetrabromide, bis (2,4-pentanedionate) titanium oxide, bis (2,4-pentanedionate ) Tetravalent titanium compounds such as titanium dichloride and bis (2,4-pentanedionate) titanium dibutoxide, and titanium chelate compounds are used. In addition, as a titanium compound, a general formula Wherein R ⁹ and R ¹⁰ each represent a halogen atom, an alkoxy group or an acyloxy group having 1 to 20 carbon atoms, preferably 1 to 10 carbon atoms, and k represents 2 to 20, preferably 2 to 10.
] May be used. Further, the titanium compound may be in a state of being adsorbed and carried on a carrier such as a magnesium compound, silica, alumina or the like, or may be a complex formed with an ester or ether. Further, the trivalent titanium compound represented by the general formula [VI] is typically a titanium trihalide such as titanium trichloride or a cyclopentadienyl titanium compound such as cyclopentadienyltitanium dichloride. Other examples include those obtained by reducing a tetravalent titanium compound. These trivalent titanium compounds may be those which form a complex with an ester, an ether or the like. The method of the present invention has two repeating units of the above-mentioned (A) transition metal compound and (B) a repeating unit represented by the general formula [I] and a repeating unit represented by the general formula [II], In addition, olefin or styrene or a styrene derivative is polymerized using both components (A) and (B) of methylaluminoxane having a molecular weight of 200 to 2,000 according to the freezing point depression method of benzene to produce an olefin polymer or a styrene polymer. I do. In the polymerization, the above-mentioned catalyst component is added to the reaction system, and then olefin or styrene or a styrene derivative as a raw material is introduced into the reaction system. The polymerization method and conditions are not particularly limited, and any of solution polymerization, suspension polymerization, gas phase polymerization and the like are possible, and both continuous polymerization and discontinuous polymerization are possible. The amount of the catalyst component to be added is 0.0001 to 0.5 mmol / l, preferably 0.001 to 0.1 when the component (A) is converted to a transition metal atom in the case of solution polymerization or suspension polymerization.
The amount of the component (B) is 50 to 100,000, preferably 100 to 10,000 as aluminum atom / transition metal atom with respect to the component (A). In the case of producing a styrene-based polymer, particularly a styrene-based polymer having a syndiotactic structure, the titanium compound as described above is used as the component (A). The ratio is the ratio of aluminum in the component (B) to titanium in the component (A), that is, 1 to 1,000,000, preferably 10 to 10,000, more preferably 50 to 1000 as aluminum atoms / titanium atoms. When producing an olefin polymer, the olefin pressure of the reaction system is from normal pressure to normal pressure.
The pressure is preferably 50 kg / cm ² G, and the reaction temperature is 0 to 200 ° C, preferably 20 to 150 ° C, more preferably 40 to 100 ° C. The molecular weight at the time of polymerization can be adjusted by known means, for example, hydrogen. The reaction time varies depending on the kind of the olefin as a raw material, and is selected, for example, from 1 minute to 2 hours in the case of ethylene and from 30 minutes to 100 hours in the case of propylene. There are various olefins that can be polymerized by the method of the present invention, for example, linear monoolefins such as ethylene, propylene, butene-1, hexene-1, and octene-1, and 4-methyl-pentene-1 and the like. The present invention can be effectively used for homopolymerization of these, or copolymerization of various olefins with each other. On the other hand, in the method of the present invention, styrene or a derivative thereof can be polymerized in addition to the above-mentioned olefin. Examples of the styrene derivative include methylstyrene (p-methylstyrene; m-methylstyrene; o-methylstyrene, etc.), dimethyl Stin (2,4-dimethylstyrene; 2,5-dimethylstyrene; 3,4-dimethylstyrene; 3,5-dimethylstyrene, etc.), ethylstyrene (p-ethylstyrene; m
-Ethylstyrene; o-ethylstyrene, etc.), i-propylstyrene (pi
-Propylstyrene; mi-propylstyrene; oi-propylstyrene)
, T-butylstyrene (pt-butylstyrene; mt-butylstyrene; o
Alkyl-substituted styrene such as t-butylstyrene) or halogen-substituted styrene (p-chlorostyrene; m-chlorostyrene; o-chlorostyrene; p-bromostyrene; m-bromostyrene; o-bromostyrene; p-fluorostyrene M-fluorostyrene; o-fluorostyrene, etc.). The polymerization of styrene or a styrene derivative may be usually performed in a hydrocarbon solvent such as an aliphatic hydrocarbon, an alicyclic hydrocarbon, or an aromatic hydrocarbon. It is also possible to carry out the reaction in the absence of a solvent. The polymerization temperature is not particularly limited, but is generally −30 ° C.
9090 ° C., preferably 0-60 ° C. Thus, it has two repeating units of the repeating unit represented by the general formula [I] and the repeating unit represented by the general formula [II], and the molecular weight of benzene is from 200 to 2000 by a freezing point depression method. By using methylaluminoxane, the polymerization activity of olefin, styrene and styrene derivative is remarkably improved. EXAMPLES Next, the present invention will be described in detail with reference to examples. Example 1 (1) Preparation of Partially Crosslinked Aluminoxane 24 ml (0.25 mol) of trimethylaluminum was placed in a 0.5-liter glass container containing 200 ml of toluene and 23.7 g (0.095 mol) of copper sulfate pentahydrate. After dropping at 20 ° C,
The reaction was stirred and the methane gas generation was 14.1 l (CH ₄ / (CH ₃ ) ₃ Al = 2.30 (molar ratio)
), The solid portion was removed, and then toluene was distilled off to obtain 6.50 g of methylaluminoxane having a partially crosslinked structure. The reaction was carried out at 40 ° C. for 24 hours. The molecular weight of the obtained methylaluminoxane was 710 according to the freezing point depression method of benzene. (2) Polymerization of propylene 400 ml of toluene, 6 mmol of an aluminum equivalent of methylaluminoxane obtained in the above (1), and 0.01 mmol of bis (cyclopentadienyl) zirconium dichloride were successively added to an autoclave having an internal volume of 1 liter, and 50 ° C. The temperature rose.
Next, propylene was continuously introduced into the autoclave, and the propylene partial pressure was increased to 8%.
While maintaining the pressure at kg / cm ² G, polymerization was carried out at 50 ° C. for 4 hours. After the polymerization, toluene was distilled off by an evaporator and dried under reduced pressure to obtain 313.2 g of polypropylene. The polymerization activity was 343 kg / g · Zr. Comparative Example 1 (1) Preparation of aluminoxane 47.2 ml (0.492 mol) of trimethylaluminum was added dropwise at 20 ° C. to a 0.5-liter glass container containing 200 ml of toluene and 35.5 g (0.142 mol) of copper sulfate pentahydrate. The reaction was further stirred for 24 hours at 20 ° C., and the amount of methane gas generated was 17.7 l (CH ₄ / (CH ₃ ) ₃
(Al = 1.5 (molar ratio)), the solid portion was removed, and then toluene was distilled off to obtain 12.4 g of methylaluminoxane. The molecular weight of the obtained methylaluminoxane was 721 by the freezing point depression method of benzene. (2) Polymerization of Propylene Propylene was polymerized in the same manner as in Example 1 (2) except that the aluminoxane obtained in the above (1) was used as the aluminoxane.
I got The polymerization activity was 63 kg / g · Zr. Example 2 400 ml of toluene, 1 mmol of the partially cross-linked methylaluminoxane obtained in (1) of Example 1 in terms of aluminum equivalent and bis (cyclopentadienyl) zirconium monochloride were placed in an autoclave having an internal volume of 1 liter. 0.005 mmol of monohydride was sequentially added, and the temperature was raised to 50 ° C. Then, propylene and ethylene were placed in an autoclave at a partial pressure of propylene of 8 kg / cm ² and a partial pressure of ethylene of 1 kg / cm ^2.
The polymerization reaction was carried out continuously at 50 ° C. for 40 minutes. After completion of the reaction, the solvent was distilled off, and the product was washed with a dilute hydrochloric acid-methanol mixed solution and then with methanol, and then dried under reduced pressure to obtain 31.7 g of a copolymer. The polymerization activity was 70 kg / g · Zr. The copolymer obtained here has a propylene content of 42.
It was a mole% of ethylene-propylene copolymer. Comparative Example 2 The procedure of Example 2 was repeated except that the methylaluminoxane obtained in (1) of Comparative Example 1 was used as the methylaluminoxane. As a result, 5.9 g of an ethylene-propylene copolymer was obtained. The polymerization activity was 13 kg / g · Zr. The propylene content of this copolymer was 50 mol%. Example 3 (Polymerization of Styrene) 100 ml of toluene and methylaluminoxane having a partially crosslinked structure obtained in Example 1 (1) in a polymerization vessel having an internal volume of 500 ml were converted to aluminum equivalent at a room temperature.
Mmol and then cyclopentadienyl titanium trichloride 0.025
After adding mmol, the temperature was raised to 50 ° C., and 17.2 ml of styrene was added, followed by polymerization for 1 hour. After completion of the reaction, the resultant was washed with hydrochloric acid-methanol and dried to obtain 9.8 g of a polymer. The polymerization activity was 8.2 kg · PS / g · Ti. Next, when this polymer was extracted with methyl ethyl ketone using a Soxhlet extractor, the extraction residue was 99.3 wt%. The weight average molecular weight of the obtained polymer was 50,000, the number average molecular weight was 23,000, the melting point by differential thermal analysis was 270 ° C., and the syndiotacticity in racemic pentad by ¹³ C-NMR measurement was 96%. Comparative Example 3 (Polymerization of Styrene) The procedure of Example 3 was repeated except that the methylaluminoxane obtained in Comparative Example 1 (1) was used as methylaluminoxane, to obtain 3.0 g of a polymer. The polymerization activity is 2.4
kg · PS / g · Ti. Then, when this polymer was extracted with methyl ethyl ketone using a Soxhlet extractor, the extraction residue was 94.6 wt%. The weight average molecular weight of the obtained polymer was 44,000, the number average molecular weight was 20,000, the melting point by differential thermal analysis was 270 ° C., and the syndiotacticity of racemic pentad by ¹³ C-NMR measurement was 95%. [Effects of the Invention] As described above, when a polyolefin, a soft resin or a polystyrene having a syndiotactic structure is produced, the use of the methylaluminoxane having a partial crosslinking point according to the present invention significantly improves the catalytic activity. Can be.

[Brief description of the drawings]   FIG. 1 is a drawing showing a process for preparing a catalyst used in the method of the present invention.

Claims (1)

Claims (1) An olefin polymer or a styrene polymer is produced by polymerizing an olefin or styrene or a derivative thereof in the presence of a catalyst comprising (A) a transition metal compound and (B) an aluminoxane. In the (A) transition metal compound,
A cyclopentadienyl compound containing any one of titanium, zirconium and hafnium is used, and (B) an aluminoxane represented by the general formula And a general formula represented by [ Wherein, m and n are each an integer of 1 or more. ] And has a freezing point of benzene
A method for producing an olefin-based polymer or a styrene-based polymer, wherein methylaluminoxane having a molecular weight of 200 to 2,000 according to the following method is used.