JPS61195102A - Polymerization of ethylene polymer - Google Patents

Abstract

PURPOSE:A catalyst which is mainly composed of a specific transition metal compound and an organometallic compound and has high polymerization activity is used to enable high-efficiency production of a polymer of narrow molecular weight distribution, which gives injection moldings of high mechanical strength. CONSTITUTION:In the polymerization of ethylene or copolymerization thereof with other alpha-olefins using a catalyst mainly consisting of (A) a transition metal compound and (B) an organometallic compound, a reaction product between a chromium carboxylate such as Cr(RCOO)3 and a halide of a metal with lower electronegativity in its ion than that of Cr<2+> such as Mg or Ca an a halogencontaining alkylaluminum compound such as dialkylaminum monohalide are used as components A and B, respectively.

Description

Detailed Description of the Invention [Industrial Application Field] The present invention relates to a method for producing an ethylene polymer, and more specifically, the present invention relates to a method for producing an ethylene polymer, and more specifically, the present invention relates to a method for producing an ethylene polymer. The present invention relates to a method for efficiently producing an ethylene polymer with a narrow width.

[Conventional technology]

BACKGROUND ART Conventionally, there has been known a method of polymerizing ethylene using a catalyst consisting of a combination of a chromium-based compound and an organoaluminum compound. However, in this method, there are problems in that the polymerization activity and properties of the catalyst are insufficient (and the polymerization pressure must be as high as several tens of atmospheres).Moreover, the ethylene polymer obtained in this way has a problem that the molecular weight distribution becomes too wide and the moldability is poor.

[Problem that the invention seeks to solve]

Therefore, the present inventor aimed to improve the polymerization activity of the catalyst and the molecular weight distribution of the produced ethylene polymer, which are the problems of the above-mentioned conventional technology, and also developed a method that enables smooth polymerization even under relatively low pressure. I did as much research as possible.

[Means for solving problems]

As a result, the inventors found that the object could be achieved by using a reaction product of a chromium carboxylate and a specific metal halide as the transition metal compound component of the catalyst, and the present invention was completed.

That is, 1. the present invention comprises (A) a transition metal compound component and (
B) In a method for producing an ethylene polymer by polymerization of ethylene or copolymerization of ethylene and other α-olefins using a catalyst containing an organometallic compound component as a main component, (^) chromium as a transition metal compound component is used. A reaction product between a carboxylate and a halide of a metal whose electronegativity of the metal ion is smaller than the electronegativity of a chromium ion, and (B) using a halogen-containing alkyl aluminum compound as an organometallic compound component. The present invention provides a method for producing an ethylene polymer characterized by the following.

The transition metal compound component, which is component (A) of the catalyst used in the method of the present invention, is a reaction product of a chromium carboxylate and a metal halide, as described above.

There are various types of chromium carboxylates, but they usually have the general formula Cr (RCOO) s or
A compound represented by Cr(RCOO)s .(RCO)go C, where R represents an alkyl group, an aryl group, or an aralkyl group having 1 to 20 carbon atoms, is used.

Specifically, Cp (CHsCOO)! , Cr
(CJsCOO) s, Cr (CsToCOO)
s.

Aliphatic carboxylates such as Cr (Cr tH21cOO) 3, Cr (C6H1COO) l Cr (Cn
3 * Aromatic carboxylates such as C6HsCOO)s, and even Cr(CHsCOO)s ・(CH,5CO)
*Addition compounds such as O and the like can be mentioned.

There are also various metal halides to be reacted with the chromium carboxylate, but it is preferable that the metal halide has a metal ion having a lower electronegativity than a chromium ion. in particular,
Magnesium, manganese or calcium halide, e.g. Eva MgC1z JgBrz, Mg1zJnC
II xJnBrt+MnIz+cacl t+Ca
Examples include Brg+Ca1z.

There is no particular restriction on the reaction between the above-mentioned chromium carboxylate and metal halide, but usually each is added to an appropriate solvent and mixed, and the reaction is carried out at a temperature of 0 to 200°C.
Preferably, the mixture may be stirred at about 30 to 100°C for about 5 to 60 minutes. Further, the mixing ratio of the chromium carboxylate and the metal halide varies depending on the type of compound used, etc., but in general, the activity of the catalyst improves as the amount of the metal halide relative to the chromium carboxylate is used in a larger amount.

Specifically, the amount of metal halide is 1 to 100 times the mole of chromium carboxylate, preferably 20 to 50 times
The amount may be adjusted appropriately within the range of twice the mole.

In the method of the present invention, the cum compound thus obtained is used as the component (B), and a catalyst containing both of these components (A) and (B) as main components is used. Examples of the halogen-containing alkyl aluminum compound as component (B) include dialkyl aluminum monohalides such as dimethylaluminum monochloride, diethylaluminum monochloride, diisopropylaluminum monochloride, diisobutylaluminum monochloride, and dioctylaluminum monochloride.

Monoalkylaluminum cibarides such as methylaluminum dichloride, ethylaluminum dichloride, isobutylaluminum dichloride.

Alkylaluminum sesquihalides such as methylaluminum sesquichloride, ethylaluminum sesquichloride, ethylaluminum sesquichloride, ethylaluminum sesquipromide, mixtures thereof, and mixtures of these and trialkylaluminum can be mentioned. Among these, the above-mentioned dialkyl aluminum monohalides are particularly preferred.

In the method of the present invention, polymerization of ethylene or copolymerization of ethylene and other α-olefins is carried out using a catalyst containing the above-mentioned components (A) and (B) as main components, but the polymerization method and conditions are particularly limited. Instead, any of solution polymerization, suspension polymerization, gas phase polymerization, etc. is possible, and both continuous polymerization and discontinuous polymerization are possible.

For example, in the case of solution polymerization or suspension polymerization, the amount of the catalyst component added is 0.0% when converting component (A) into chromium atoms.
001-5.0 mmol/1. Preferably 0,005~
1 mmol/1, and the ratio of component (B) to the chromium atoms in component (A) is 1 to 5000 (mole ratio), preferably 5 to roooJ (mole ratio), and the olefin pressure in the reaction system is is normal pressure to 50 kg/cjG, preferably normal pressure to 20 kg/cdG, and the reaction temperature is 0 to 150°C.
The molecular weight during the polymerization, preferably at 20 to 80° C., can be controlled by known means, such as temperature control.

In the method of the present invention, ethylene can be homopolymerized, and ethylene and other α-olefins (eg, propylene, butene-1, hexene-1°octene-1, etc.) can also be copolymerized.

〔Effect of the invention〕

According to the method of the present invention, the activity of the catalyst used is significantly higher than that of conventional chromium-based catalysts, and the resulting ethylene-based polymer has a narrow molecular weight distribution, resulting in injection molded products with high mechanical strength.

Therefore, according to the method of the present invention, an ethylene polymer having excellent mechanical strength can be produced very efficiently.

〔Example〕

Next, the present invention will be explained in more detail with reference to Examples.

Example 1 (1) Preparation of catalyst component raw material Nichromium acetate hydrate (Cr(CHsCOO)s ・1
itu) with a mixture of acetic anhydride and acetic acid at 120°C.
The formula Cr(CHsCOO)s ・(CHs
An adduct compound represented by CO) to was obtained.

Dissolve in 1 mmol of 1-hexanol and make a solution■
I got it. On the other hand, dissolve 10 mmol of magnesium chloride in 90 mmol of 2-ethyl-1-hexanol and make a solution of
I got it.

(2) Polymerization of ethylene under a nitrogen atmosphere with a magnetic stirrer.
Add the solution obtained in (1) above to a 0ml reaction vessel! 0.016 mmol as an addition compound and solution ■0.6 mmol as magnesium chloride and 160 mmol of toluene! added.

Next, after slightly reducing the pressure in the reaction vessel, ethylene was introduced to saturate the ethylene and stirred at 30°C for 20 minutes to prepare a reaction product of the above addition compound and magnesium chloride. 14 mmol of monochloride was added, and a polymerization reaction was carried out at normal pressure and 30° C. for 24 hours.

As a result, 4.6 g of polyethylene was obtained. In this case, the catalyst activity is 6 kg of polyethylene per gram of chromium atom.
(6 kg/g-Cr). In addition, the polyethylene obtained here was subjected to eel Pera + ation Ch at 145°C using 1.2.4*lolobenzene as a solvent.
As a result of rolIatography (GPC) measurement, the weight average molecular weight (M) was 3,300,000. The number average molecular weight (M, %) was 1,530,000, and the ratio M, /M, was 2.2.

Comparative Example 1 The same operation as in Example 1 was performed except that magnesium chloride was not added as a catalyst component.

As a result, the yield of polyethylene was 0.5 g, and the catalyst activity was 0.6 kg/g-Cr. The M of the obtained polyethylene was 616,000. M.

was 17,000, and M,/M, was 35.5.

Example 2 The same operation as in Example 1 was performed except that manganese chloride was used instead of magnesium chloride as a catalyst component.

As a result, the yield of polyethylene was 2.7 g, and the catalyst activity was 3 kg/g-Cr.

Example 3 The same operation as in Example 1 (2) was performed except that ethyl aluminum sesquichloride was used in place of diethyl aluminum monochloride in Example 1 (2).

As a result, the yield of polyethylene was 1.0 g, and the catalyst activity was 1 kg/g-Cr.

Comparative Example 2 The same operation as in Example 1 was performed except that aluminum chloride was used instead of magnesium chloride as a catalyst component.

As a result, the yield of polyethylene was 0.05 g, and the catalyst activity was 0.07 kg/g-Cr.

Comparative Example 3 The same operation as in Example 1 was performed except that niobium pentachloride was used instead of magnesium chloride as a catalyst component.

As a result, the yield of polyethylene was 0.02 g, and the catalyst activity was 0.03 kg/g-Cr.

Example 4 400 ml of toluene and the solution I obtained in Example 1 (1) were placed in an argon-substituted autoclave with an internal volume of 11.
Added 0.008 mmol of solution (1) as an addition compound and 0.3 mmol of solution (1) as magnesium chloride, and heated at 50°C for 20 minutes.
Stir for a minute. Next, 7 ml of diethylaluminium monochloride was added, and ethylene was continuously supplied so that the ethylene pressure became 8 kg/cm"G, and the polymerization reaction was carried out for 1 hour to obtain 48 g of polyethylene. The catalyst activity was 11
It was 6 kg/g-cr.

Example 5 Chromium stearate (C
The same operation as in Example 4 was performed except that a toluene solution of r(C+JssCOO)s) was used.

As a result, the yield of polyethylene was 63 g, and the catalytic activity was 151 g/g-Cr.

Comparative Example 4 Chromium stearate (C
The same operation as in Example 4 was carried out, except that the toluene solution of r(C+JzsCOO)a) was used and the magnesium chloride solution (2) was not used.

As a result, 0.6 g of polyethylene was obtained. The catalytic activity is
It was 1 kg/g-Cr.

] 1 copy of the procedural dispute letter) April 2, 1985

Claims (4)

[Claims] (1) A method for producing ethylene polymers by polymerizing ethylene or copolymerizing ethylene and other α-olefins using a catalyst whose main components are (A) a transition metal compound component and (B) an organometallic compound component. (A) a reaction product of a chromium carboxylate as a transition metal compound component and a metal halide whose electronegativity of the metal ion is smaller than the electronegativity of the chromium II valent ion; and (B)
A method for producing an ethylene polymer, comprising using a halogen-containing alkyl aluminum compound as an organometallic compound component. (2) Chromium carboxylate has the general formula Cr(RCOO
)_3 or Cr(RCOO)_3・(RCO)_2
O [In the formula, R represents an alkyl group, an aryl group, or an aralkyl group having 1 to 20 carbon atoms. ] The manufacturing method according to claim 1, which is a compound represented by: (3) The manufacturing method according to claim 1, wherein the metal of the metal halide is magnesium, calcium, or manganese. (4) The manufacturing method according to claim 1, wherein the halogen-containing alkyl aluminum compound is a dialkyl aluminum monohalide.