JPH0749448B2 - Method for producing ethylene-based polymer - Google Patents

Description

TECHNICAL FIELD The present invention relates to a method for producing an ethylene-based polymer, and more particularly, to an ethylene-based polymer using a catalyst containing a specific transition metal compound component and an organometallic compound component as main components. The present invention relates to a method for efficiently producing a polymer.

[Problems to be Solved by Conventional Techniques and Inventions] Conventionally, a catalyst comprising a combination of acetylacetonato chromium and an organoaluminum compound has been used in the polymerization of ethylene or the copolymerization of ethylene with other α-olefins. It is known (Japanese Patent Laid-Open No. 51-106692).
issue).

However, the catalyst composed of a combination of these two components has a problem that the ethylene polymerization activity is not sufficient.

[Means for Solving Problems] Therefore, the inventors of the present invention have conducted various studies to solve the problems of the conventional techniques, and as a result, as a transition metal compound component of the catalyst, a chromium chelate compound and chromium π- At least one chromium compound selected from the group consisting of complexes and chromium aryl compounds, and a manganese carboxylate salt,
The inventors have found that the polymerization activity of ethylene is remarkably improved by using a contact-treated product with an organic phosphorus-containing compound of manganese or an organic phosphorus-containing compound of magnesium, and have completed the present invention.

That is, according to the present invention, an ethylene-based polymer is produced by polymerizing ethylene or copolymerizing ethylene with another α-olefin using a catalyst containing a transition metal compound component (A) and an organometallic compound component (B) as main components. In the method
(A) At least one chromium compound selected from the group consisting of a transition metal compound component (i) a chromium chelate compound, a chromium π-complex and a chromium aryl compound; and (ii) a manganese carboxylate salt and a manganese organophosphorus compound. A method for producing an ethylene-based polymer, which comprises using a halogen-containing alkylaluminum compound as a component (B) of an organometallic compound, as well as using a compound treated with a compound containing magnesium or an organic phosphorus-containing compound of magnesium. is there.

The transition metal compound component which is the component (A) of the catalyst used in the method of the present invention is at least one chromium compound selected from the group consisting of (i) a chromium chelate compound, a chromium π-complex and a chromium aryl compound as described above. And (i
i) A magnesium compound or a contact-treated product with a manganese compound.

The chromium chelate compound is specifically a chromium trisacetylacetonate represented by the formula Cr (acac) ₃ , Cr (mb
chromium tris represented by d) ₃ (2-methyl-1,3-butane dionate), chromium tris represented by Cr (bd) ₃ (1,3- butane dionate) and the like. Here (acac) is an acetylacetonate group, and chromium trisacetylacetonate is It is represented by the structural formula: Also, (mbd) is 2-methyl-
1,3-butanedionate group is shown, and chromium tris (2-
Methyl-1,3-butanedionate) is It is represented by the structural formula: Further, (bd) represents a 1,3-butanedionate group, and chromium tris (1,3-butanedionate) is It is represented by the structural formula:

As the chromium π-complex, biscyclopentadienyl chromium represented by (cp) ₂ Cr ((cp) represents a cyclopentadienyl group), bisbenzene chromium represented by (C ₆ H ₆ ) ₂ Cr, Diphenylbenzene chromium represented by (2C ₆ H ₅ ) (C ₆ H ₆ ) Cr, formula Dihexamethylbenzenechromium represented by the formula Π-cyclopentadienyl bromochromium acetyl acetate represented by Π-cyclopentadienyl (benzene) chromium represented by Aromatic ring π-complexes such as π-cyclopentadienyl-π-cycloheptadienylchromium, and π-allyl complexes such as tris (η-allyl) chromium and tetrakis (η-allyl) chromium .

Furthermore, examples of the chromium aryl compound include diphenyl chromium and tetraphenyl tris tetrahydrofuran.

In addition, (i) chromium compound is contact-treated (ii)
The compound is a carboxylate salt of manganese, an organic phosphorus-containing compound of manganese, or an organic phosphorus-containing compound of magnesium.

The manganese carboxylic acid salt is specifically shown here by the general formula Mn (R ¹ COO) ₂ or Mn (R ¹ COO) X [wherein R ¹ is an alkyl group having 1 to 20 carbon atoms, an aryl group, or Represents an aralkyl group, and X represents a halogen atom. ] It is manganese carboxylate represented by.

In the above general formula representing manganese carboxylate, R ¹ is as described above, preferably an aliphatic alkyl group having 6 or more carbon atoms, particularly preferably an aliphatic alkyl group having 8 or more carbon atoms, Hexyl group, heptyl group, octyl group, 2-ethylhexyl group, nonyl group,
Examples include decyl group, lauryl group, myristyl group, heptadecyl group, and stearyl group. Further, an unsaturated alkyl group such as oleyl group can be used.

There are various organic phosphorus-containing compounds of magnesium or manganese, and there is no particular limitation, but those obtained by reacting an organic magnesium compound or an organic manganese compound with a hydrogen-containing phosphorus compound are preferable. Here, the organomagnesium compound or organomanganese compound is represented by the general formula R ² R ³ M [wherein, R ² and R ³ are each an alkyl group or aryl group having 1 to 10 carbon atoms, and M is magnesium or manganese. ] The compound represented by
Alternatively, R ² MX [in the formula, R ² represents an alkyl group or aryl group having 1 to 10 carbon atoms, M represents magnesium or manganese, and X represents a halogen atom. ] The compound represented by the following can be given as a preferable example. In particular,
Examples include ethylbutyl magnesium, dibutyl magnesium, diethyl magnesium, dihexyl magnesium, dimethyl manganese, diphenyl manganese, ethyl magnesium chloride, ethyl magnesium iodide, methyl manganese iodide. Further, complex salts with these organoaluminum and organozinc can also be used.

On the other hand, examples of the hydrogen-containing phosphorus compound include alkylphosphine, ethylphosphine, propylphosphine, butylphosphine, phenylphosphine, and other alkyl or arylphosphines; diethylphosphine, dipropylphosphine, dibutylphosphine, diphenylphosphine, and other dialkyl or diarylphosphines. , Alkyl or aryl phosphonic acids such as ethylphosphonic acid and propylphosphonic acid, diethyl phosphinic acid, dipropylphosphinic acid, dibutylphosphinic acid, didodecylphosphinic acid, dialkyl or diarylphosphinic acids such as diphenylphosphinic acid, and phosphorous methyl ester , Phosphite butyl ester, phosphite dimethyl ester, phosphite dipropyl ester, phosphite dibutyl ester, phosphite Phosphate dodecyl ester, phosphite dilauryl phosphite, dioleyl phosphite esters such as phosphorous acid diphenyl ester,
There are phosphoric acid esters such as phosphoric acid ethyl ester, phosphoric acid propyl ester, phosphoric acid dipropyl ester, phosphoric acid dibutyl ester, phosphoric acid dioctyl ester, and phosphoric acid didodecyl ester.

There are no particular restrictions on the contact treatment of the above-mentioned (i) chromium compound and (ii) manganese carboxylate, manganese organic phosphorus-containing compound, or magnesium organic phosphorus-containing compound. Add to solvent and mix, temperature 0-200 ℃, preferably 30-100
It suffices to stir at a temperature of about 5 to 60 minutes. The mixing ratio of both the compounds (i) and (ii) varies depending on the kind of the compound used, etc., but in general, (ii) a carboxylate salt of manganese, an organic phosphorus-containing compound of manganese, or an organic phosphorus-containing compound of magnesium. The larger the amount of (i) used with respect to the chromium compound, the more the catalyst activity improves. Specifically, with respect to (i) chromium compound, (ii) manganese carboxylate, manganese organophosphorus compound or magnesium organophosphorus compound is 1 to 100 times mol, preferably 20 to 50 times mol. It may be appropriately determined within the range of moles.

In the method of the present invention, a product obtained by contacting the thus obtained (i) chromium compound and (ii) manganese carboxylate, manganese organic phosphorus-containing compound or magnesium organic phosphorus-containing compound (A) As a component, a halogen-containing alkylaluminum compound is used as a component (B), and a catalyst containing both of these components (A) and (B) as a main component is used.
Examples of the halogen-containing alkylaluminum compound which is the component (B) include dialkylaluminum monohalides such as dimethylaluminum monochloride, diethylaluminum monochloride, diisopropylaluminum monochloride, diisobutylaluminum monochloride, dioctylaluminum monochloride, methylaluminum dichloride, ethyl. Aluminum dichloride, monobutyl aluminum dihalide such as isobutyl aluminum dichloride, methyl aluminum sesquichloride,
Examples include alkylaluminum sesquihalides such as ethylaluminum sesquichloride and ethylaluminum sesquibromide, and mixtures thereof, and further mixtures of these with trialkylaluminum. Of which
The above-mentioned dialkylaluminum monohalide is particularly preferable.

In the method of the present invention, ethylene or a copolymer of ethylene and another α-olefin is polymerized using a catalyst containing the above-mentioned components (A) and (B) as a main component. There is no limitation, and any of solution polymerization, suspension polymerization, gas phase polymerization, etc. is possible, and both continuous polymerization and discontinuous polymerization are also possible.

In this case, aliphatic hydrocarbons, alicyclic hydrocarbons, aromatic hydrocarbons and halogenated hydrocarbons are used as the polymerization solvent. The reaction temperature 0 to 150 ° C. As the polymerization conditions, preferably 20 to 80 ° C., the reaction pressure is atmospheric pressure to 50 kg / cm ² G, preferably normal pressure ~20kg / cm ² G.

The catalyst composition is not particularly limited, but is usually 1 to 5000 (molar ratio) of the aluminum atom of the component (B) to the chromium atom in the component (A), preferably 5 to 1000.
(Molar ratio), and in the component (A), the magnesium atom or the manganese atom is 1 to 1 with respect to the chromium atom.
It is 100 (molar ratio), preferably 20 to 50 (molar ratio).

For example, in the case of solution polymerization or suspension polymerization, the addition amount of the catalyst component is 0.00 when the component (A) is converted to chromium atoms.
1 to 5.0 mmol / m, preferably 0.005 to 1 mmol / m
And The molecular weight at the time of polymerization can be adjusted by a known means such as temperature adjustment.

In the method of the present invention, ethylene can be homopolymerized, or ethylene can be copolymerized with other α-oleins (eg, propylene, butene-1, hexene-1, octene-1).

[Effects of the Invention] According to the method of the present invention, the activity of the catalyst used is remarkably higher than that of the conventional chromium-based catalyst, and the obtained ethylenic polymer has high mechanical strength of the injection-molded article.

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

EXAMPLES Next, the present invention will be described in more detail with reference to examples.

Example 1 (1) Preparation of (i) and (ii) of catalyst component (A) 2.1 g (6 mmol) of trisacetylacetonatochromium was dissolved in 200 ml of toluene to obtain a catalyst component (i).

In a flask having an internal volume of 200 ml, 50 ml of heptane and 6.45 g (20 mmol) of di-2-ethylhexyl phosphate were added, and then 30 ml of a solution of 10 mmol of ethylbutylmagnesium in heptane was added dropwise at room temperature over 20 minutes.

Next, this was heated and reacted under reflux of heptane for 3 hours, then heptane was distilled off and 100 ml of toluene was added to obtain a catalyst component (ii).

(2) Polymerization of ethylene 400 ml of toluene was put into an autoclave having an internal volume of 1 and purged with argon, and 0.008 mmol of the catalyst component (i) obtained in the above (1) as a chromium atom and a magnesium atom of the catalyst component (ii). As 0.32 mmol,
The mixture was stirred and mixed at 40 ° C. for 20 minutes (catalyst component (A)).

Then, 7 mmol of diethylaluminum monochloride as a catalyst component (B) was added to this mixed solution, ethylene was continuously introduced, and the polymerization reaction was carried out for 1 hour while maintaining the pressure at 8 kg / cm ² G. As a result, the polyethylene yield was 8
It was 5.4 g, and the catalytic activity was 205 kg / g · Cr.

Example 2 The same operation as in (2) of Example 1 was carried out except that the amount of the catalyst component (ii) used in (2) of Example 1 was 0.64 mmol as magnesium atom. As a result, the yield of polyethylene was 92 g, and the catalytic activity was 221 kg / g.Cr.
Met.

Comparative Example 1 The same operation as in (2) of Example 1 was performed except that the catalyst component (ii) was not used in (2) of Example 1. As a result, the polyethylene yield was 0.32 g, and the catalytic activity was 0.77 kg / g.Cr.

Example 3 The same operation as in (2) of Example 1 was carried out except that 7 mmol of diisobutylaluminum monochloride was used in place of diethylaluminum chloride as the catalyst component (B) in (2) of Example 1. . As a result, the yield of polyethylene was 35.1 g, and the catalytic activity was 84.4 kg / g.Cr.
Met.

Example 4 In Example 1 (2), the catalyst component (B) was replaced with diethylaluminum monochloride and a mixture of triethylaluminum 3.5 mmol and diethylaluminum monochloride 3.5 mmol was used. The same operation as 2) was performed. As a result, the polyethylene yield was 48.6 g, and the catalytic activity was 117 kg / g · Cr.

Example 5 The same operation as in (2) of Example 1 was performed except that 0.196 g (0.32 mmol) of manganese stearate was used in place of the catalyst component (ii) in (2) of Example 1. As a result, the yield of polyethylene was 20.4 g, and the catalytic activity was 49 kg / g · Cr.

Example 6 (1) Preparation of (i) of catalyst component (A) In a flask with an internal volume of 200 ml replaced with argon,
Biscyclopentadienyl chromium 1.22 g (6.7 mmol)
Was dissolved in 200 ml of toluene to obtain a catalyst component (A) (i).

(2) Polymerization of ethylene As (i) of the catalyst component (A), 0.008 mmol of the chromium component of (i) of the catalyst component (A) prepared in (1) above was used, and (2) of Example 1 was used. ). As a result, the polyethylene yield was 22 g, and the catalytic activity was 5
It was 2.9 kg / g · Cr.

Comparative Example 7 The procedure of (2) of Example 7 was repeated, except that the magnesium compound of (ii) of the catalyst component (A) was not used in (2) of Example 6. As a result, the polyethylene yield was 0.77 g, and the catalytic activity was 1.85 kg / g · Cr.

Example 7 (1) Preparation of (i) of catalyst component (A) In a flask having an inner volume of 200 ml and purged with argon,
Toluene 200 with 1.51 g (7.33 mmol) of diphenyl chromium
It was dissolved in ml to obtain catalyst component (A) (i).

(2) Polymerization of ethylene As the catalyst component (A) (i), the catalyst component (A) (i) prepared in the above (1) was used in an amount of 0.008 mmol as a chromium atom. Same as 2). As a result, the yield of polyethylene was 26 g, and the catalytic activity was 62.5 kg / g · Cr.

Comparative Example 3 The procedure of (2) of Example 7 was repeated, except that the magnesium compound of (ii) of the catalyst component (A) was not used in (2) of Example 7. As a result, the yield of polyethylene was 0.42 g, and the catalytic activity was 1.0 kg / g · Cr.

[Brief description of drawings]

FIG. 1 is a drawing showing the steps for preparing a catalyst used in the method of the present invention.

Claims (5)

[Claims] 1. An ethylene polymer is produced by polymerizing ethylene or copolymerizing ethylene with another α-olefin using a catalyst containing (A) a transition metal compound component and (B) an organometallic compound component as main components. In the method, (A) a transition metal compound component (i) a chromium chelate compound,
Using a contact-treated product of at least one chromium compound selected from the group consisting of chromium π-complexes and chromium aryl compounds, and (ii) a manganese carboxylate, an organic phosphorus-containing compound of manganese, or an organic phosphorus-containing compound of magnesium. In addition, a halogen-containing alkylaluminum compound is used as the organometallic compound component (B) together with the method for producing an ethylene polymer. 2. A chromium chelate compound having the formula Cr (acac) ₃
[In the formula, acac represents an acetylacetonate group. ] The manufacturing method of Claim 1 which is tris acetylacetonato chromium represented by these. 3. A chromium π-complex is represented by the formula (cp) ₂ Cr [wherein c
p represents a cyclopentadienyl group. ] The manufacturing method of Claim 1 which is biscyclopentadienyl chromium represented by these. 4. A chromium aryl compound has the formula (C ₆ H ₅ ) ₂ Cr
The process according to claim 1, which is diphenylchromium represented by 5. The process according to claim 1, wherein the halogen-containing alkylaluminum compound is a dialkylaluminum monohalide.