JPS588694B2 - Ethylene polymerization method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for polymerizing ethylene, and more particularly to a method for efficiently polymerizing ethylene using a specific catalyst.

Conventionally, when polymerizing ethylene, a magnesium-containing compound such as magnesium halide, magnesium alkoxide, etc. is used as a catalyst carrier, and a substance obtained by reacting this substance with a titanium halide becomes a component of a highly active catalyst. It has been known.

Regarding the use of the reaction product of magnesium alkoxide and titanium halide as a catalyst component, Japanese Patent Publication No. 46
Although it is specifically described in Japanese Patent No. 34098, the catalyst activity and the quality of the polyethylene obtained are not satisfactory.

Furthermore, a method in which magnesium alkoxide is treated with organoaluminum or a halogenating agent and then reacted with a titanium compound (Japanese Patent Publication No. 47-43435, Japanese Patent Publication No. 5
1-30118) or a method in which magnesium alkoxide is reacted with a titanium compound in the presence of a halogenating agent, an electron-donating compound, a halogenated silane, or a boron compound (Japanese Patent Publication No. 1983-30118, Japanese Unexamined Patent Application Publication No. 1983-1983)
Improvement methods such as those disclosed in Japanese Patent Application Laid-Open No. 7-32081, Japanese Patent Application Laid-Open No. 52-98076, and Japanese Patent Application Laid-Open No. 51-40915) are known.

Although these methods can be expected to increase activity to some extent,
However, it is difficult to say that the results are satisfactory.

On the other hand, a method of reacting metallic magnesium with alcohol in the presence of silicon halide (Japanese Patent Publication No. 50-23864
Although it has also been proposed, it is not desirable in terms of carrier preparation and activity.

The ultimate purpose of the methods for high-activity polymerization of ethylene as described above is to further increase the activity, omit the catalyst removal step, simplify the manufacturing process, and improve the quality of the resulting product. The more the activity is improved, the more desirable it is.

From this point of view, in the process of conducting detailed studies on a method for polymerizing ethylene using a catalyst containing a reaction product of a magnesium compound and a titanium halide, the present inventors found that magnesium dialkoxide and magnesium sulfate were used as magnesium compounds. It was discovered that a catalyst prepared using a mixture of the above has improved polymerization activity compared to the catalyst described in the above-mentioned Japanese Patent Publication No. 46-34098, which uses magnesium dialkoxide alone, and as a result of further investigation, It has been found that the polymerization activity can be dramatically improved by using a solid substance obtained by contact reaction with (1) a halide of silicon or an organic compound, or (2) a halide of silicon.

The present invention was completed based on this knowledge.

That is, the present invention provides a method for polymerizing ethylene using a catalyst containing (A) a reaction product of a magnesium compound and a titanium halide and (B) an organoaluminum compound, in which magnesium dialkoxide is used as the component (A). A solid product obtained by contacting and reacting a mixture of magnesium sulfate with a silicon halide or organic compound or a silicon halide or organic compound and an alcohol, and then reacting the resulting solid substance with a titanium halide. The present invention provides a method for polymerizing ethylene, which is characterized in that it is used.

The magnesium dialkoxide used in the present invention is usually represented by the general formula Mg(OR)2, where R is an alkyl group, alkenyl group, or aryl group having 1 to 20 carbon atoms, preferably 1 to 8 carbon atoms. , cycloalkyl group, arylalkyl group, alkylaryl group, etc.

Specifically, magnesium dimethoxide, magnesium diethoxide, magnesium dipropoxide, magnesium dibutoxide, magnesium dicyclohexoxide,
Magnesium dibenzogide and the like are preferred.

In addition to the above-mentioned magnesium dialkoxides of the present invention, when used with other metals, alkoxides and monoalkoxides having halogen carboxyl groups, hydroxyl groups, etc. can also be used.

The preferred average particle size of the magnesium dialkoxide of the present invention is 1 to 500 microns.

Commercially available magnesium dialkoxides can be used, but they may also be produced by reacting metallic magnesium and alcohol.

In the latter case, the efficiency and polymerization activity can be improved, especially if the reaction is carried out in the presence of magnesium sulfate to be mixed.

The preparation method when using metallic magnesium is as follows.

That is, a predetermined amount of magnesium metal, magnesium sulfate, and excess alcohol are added to a hydrocarbon solvent such as hexane or heptane, or the alcohol itself is used as a solvent and heated to 70 to 100°C to cause a complete reaction.

Next, the solvent is distilled off, and the resulting solid is thoroughly dried and pulverized.

For pulverization, a known method such as a ball mill may be used.

Note that examples of the alcohol used here include methanol, ethanol, ingropanol, butanol, and octanol.

As the magnesium compound of the present invention, a mixture of the above-mentioned magnesium dialkoxide and magnesium sulfate is used.

Magnesium sulfate may or may not contain water of crystallization.

The average particle size is preferably about 0.1 to 100 microns.

The component (A) in the catalyst used in the method of the present invention is adjusted as follows.

That is, usually, the above-mentioned magnesium dialkoxide and magnesium sulfate are first dispersed in an inert solvent.

In this case, the amount of the total magnesium compound consisting of magnesium dialkoxide and magnesium sulfate is not particularly limited, but for convenience of operation, it is 50 to 500 g per liter of solvent.
It is preferable that

Furthermore, the mixing ratio of magnesium dialkoxide and magnesium sulfate is not particularly limited and may be selected appropriately depending on various conditions, but generally magnesium dialkoxide is mixed with 1
The amount is in the range of 0.01 to 10 mol, preferably 0.05 to 5.0 mol, per mol of magnesium sulfate.

Outside this range, the synergistic effect of improving the activity of the catalyst by both will be extremely low.

Subsequently, (1) a silicon halide or organic compound, or (2) a silicon halide or organic compound and alcohol are added to this dispersion system and reacted with stirring at a predetermined temperature and time to denature the magnesium compound.

The reaction temperature at this time is usually 0 to 200°C, especially 30 to 15°C.
It is preferable to adjust the temperature to 0°C because it is efficient and the polymerization activity of the resulting catalyst is high, and the bulk specific gravity of polyethylene produced using this catalyst is also high.

Although the reaction time depends on the reaction temperature, it is usually 10 minutes to 5 hours, preferably 30 minutes to 3 hours.

When using alcohol, there are no particular restrictions on the order in which the magnesium compound, silicon compound, and alcohol are brought into contact with each other, but generally the magnesium compound is suspended in a solvent, the silicon compound is added thereto, and then the alcohol is added to react. A method in which the silicon compound and the alcohol are added in the opposite order can be advantageously implemented.

In addition, all the components can be added and brought into contact at the same time.

If the silicon halide used in the above reaction is an organic compound, there is no particular restriction, but the formula XnSi (OR
1) 4-n [wherein X is a halogen atom, R1 has 1 to 1 carbon atoms]
6 alkyl group or aryl group, n represents any integer of 0 to 4.

] is preferable, specifically SiC14
, CH3OSiCl3, (CH3O)2SiC12, (
CH3O)3sic1, Si (OCH3)4, C2H
50SiCl3, (C2H5O)2sicl2, (C2
H5O)3Sic1, Si(OC2H3)4, C3H7
OSiCl3, (C3H70)2SiC12, (C3H
7O)3SiC1, Si(OC3H7)4, C6H5O
SiC13, (C6H5O)2SiC12, (C6H5
O)3SICI, Si(C6H5O)4, etc. can be mentioned.

Among these, halogen-containing compounds such as SiCl4 and dialkoxy di-silicon chloride are particularly preferred.

Also, the formula XmSiR24-m [wherein X is a halogen atom, R
2 represents an alkyl group or an aryl group having 1 to 6 carbon atoms, and m represents an integer of 0 to 3.

] or the formula R3pSi(OR4) 4-p
[In the formula, R3 and R4 are an alkyl group or an aryl group having 1 to 6 carbon atoms, and p is an integer of 1 to 3.

] can also be used.

The amount of these silicon compounds used is usually 0.05 to 50, preferably 0.1 to 50 in molar ratio to the total magnesium compound.
Set it to 10.

If the amount of the silicon compound used is too small, the activity of the catalyst and the bulk specific gravity of the produced polymer will not be sufficiently improved.

Furthermore, if too large a quantity is used, the polymerization activity will not be improved, but rather the reactant will be wasted.

The alcohol used in the present invention is a linear or side chain aliphatic or aliphatic alcohol, and primary or secondary alcohols having 1 to 8 carbon atoms are particularly preferred.

Specifically, CH3OH, C2H5OH, C3H7OH,
C4H9OH, C5H11OH, C6H13OH, C5
Examples include H11OH.

Among these, ethanol, isopropanol and the like are particularly preferred.

The amount used is usually 0.0 molar ratio to the total magnesium compound.
1 or more, preferably 0.2 to 100.

The use of alcohol further increases the polymerization activity and bulk specific gravity of the polymer.

However, if too large a quantity is used, no improvement in polymerization activity will be observed, and rather the reactant will be wasted.

Further, the solvent used in the above reaction is not particularly limited as long as it is inert and does not react with the above magnesium compound, silicon compound and alcohol.
Examples include various solvents such as aliphatic hydrocarbons and aromatic hydrocarbons.

Specifically, butane, pentane, hexane, heptane, cyclohexane, etc. are suitable.

Although the reaction using a solvent as described above is a preferred embodiment of the present invention, it is also possible to carry out the reaction without a solvent.

In this case, for example, a predetermined ratio of the magnesium compound, silicon compound, and alcohol may be directly mechanically mixed and reacted using a ball mill or the like.

The thus obtained modified magnesium compound is used in the next reaction in the reaction dispersion as it is, or after washing and separating the modified solid.

Note that the modified product may be further treated with an organoaluminum compound and used in the next reaction.

The organoaluminum compound used in this treatment has the formula AIR
5rX3-r (where X is a halogen atom, R5 is an alkyl group having 1 to 6 carbon atoms, and r is an integer of 1 to 3).

) and aluminum sesquihalide are preferred.

The amount of the organoaluminum compound to be used is usually 100 times the molar amount or less relative to the total magnesium compound.

The treatment is carried out in a hydrocarbon solvent having 4 to 10 carbon atoms such as hexane or heptane at a temperature of -10 to +100°C, preferably 2
Both are brought into contact with each other under stirring at 0 to 50°C for 0.1 to 3 hours.

Component (A) in the catalyst used in the method of the present invention may be a solid product obtained by further reacting a modified magnesium compound with a titanium halide.

The halogenated titanium used here is not particularly limited as long as it is a tetravalent, trivalent or divalent halogen-containing titanium compound, but it has the formula XqTi(OR6)4-q [where X is a halogen atom and R6 is the number of carbon atoms] 1 to 6 alkyl groups or aryl groups; q represents an integer of 1 to 4;

] is preferable, and a specific example is Ti
C1,,C2H50TIC13(C2H50)2Tic
l2, (C2H50)3Tic1, etc.

The reaction between a modified magnesium compound and a titanium halide is usually carried out in a hydrocarbon solvent, but it can also be carried out without a solvent.

When carried out in a solvent, a predetermined amount of titanium halide is added to the reaction solution for producing a modified product by the solvent method, or when processing such as washing and separation of the reaction solid is performed, the modified product is dispersed again in an inert solvent. Add a predetermined amount of titanium halide,
Normally 0 to 200°C, preferably 5°C under normal pressure or increased pressure.
The reaction is stirred and reacted at a temperature of 0 to 150°C for usually 10 minutes to 5 hours, preferably 30 minutes to 3 hours.

On the other hand, in the case of a solventless reaction, mechanical mixing using a ball mill or the like may be performed at the above temperature and time.

The amount of titanium halide to be used is usually at least 1 mol, preferably in excess, based on the total amount of magnesium compound used.

If the amount of titanium halide used is too small, the polymerization activity and bulk specific gravity of the polymer will not be sufficiently improved.

Note that when the reaction between the modified magnesium compound and the titanium halide is carried out in the presence of a silicon halide or an organic compound, the polymerization activity and the bulk specific gravity of the polymer are further improved.

As the silicon halide or organic compound here, the same ones as those mentioned above for the modified product production reaction can be used, but those containing an alkoxy group are particularly preferred.

When a titanium halide is added to a reaction solution for producing a modified product by a solvent method, the silicon compound contained in the reaction solution acts effectively.

The amount of the silicon compound to be used is generally 0.05 to 50, preferably 0.1 to 10 in molar ratio to the total magnesium compound used as above.

After carrying out the above reaction between the modified magnesium compound and the titanium halide, solid components are separated and washed from the reaction product.

This washing is carried out using an inert hydrocarbon solvent having 5 to 10 carbon atoms, such as pentane, hexane, cyclohexane, heptane, etc.

The washed solid product is further dispersed in an inert hydrocarbon solvent in an inert gas at an appropriate concentration and used as a catalyst component.

Note that the solid product after washing may be further treated with organoaluminum and then made into a dispersion as described above. In this case, the polymerization activity of the catalyst and the bulk specific gravity of the polyethylene to be polymerized are further increased.

The organoaluminum compound that can be used in this case may be the same as the organoaluminum compound as the catalyst component (B) described later, or may be different.

It is sufficient that the amount used is approximately equal to or more than the amount of supported titanium.

The method of the present invention uses a reaction product of the above-mentioned modified magnesium compound and titanium halide as the component (A),
(A) with an organic aluminum compound as the component (B), (
B) Conducted using a catalyst consisting of both components.

In polymerizing ethylene, a dispersion of the prisoner component and an organoaluminum compound as component (B) are added as a catalyst to the reaction system, and then ethylene is introduced into the system.

There are no particular restrictions on the polymerization method and conditions, and solution polymerization,
Both suspension polymerization and gas phase polymerization are 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 usually 0.001 to 5 mmol/l for component (A), while the amount of component (B) is 0.001 to 5 mmol/l relative to component (A). 10
~iooo (molar ratio), preferably 30 to 500 (molar ratio).

In addition, the ethylene pressure in the reaction system is usually normal pressure to 100 kg/c.
m2, preferably 2 to 20 kg/cm2, the reaction temperature is usually 0 to 200°C, preferably 50 to 150°C, and the reaction time is usually 10 minutes to 5 hours, preferably 0.5 to 3
Time.

Although the molecular weight of polyethylene can be controlled to some extent by polymerization conditions such as polymerization temperature, catalyst concentration, and catalyst molar ratio, it is more effective to carry out the polymerization in the presence of hydrogen.

There is no particular restriction on the organoaluminum compound that is the component (B) of the catalyst used in the method of the present invention, but
'3A1, R'2AIX1R'3Al2X3, R'2A
IOR' [wherein R' and R' are an alkyl group or an aryl group having 1 to 6 carbon atoms, and X is a halogen atom.

] are preferred, and specific examples include trimethylaluminum, triethylaluminum, triisopropylaluminum, triisobutylaluminum,
Examples include diethylaluminum monochloride, diisopropylaluminium monochloride, diisobutylaluminum monochloride, diethylaluminum monoethoxide, and ethylaluminum sesquichloride.

In the method of the present invention, not only the homopolymerization of ethylene, but also the copolymerization of ethylene with a small amount of α-olefin, such as propylene, putene-1, and hexene-1, can be effectively carried out.

Note that the catalyst used in the method of the present invention may further contain an organic metal such as organic zinc.

Since the catalyst used in the method of the present invention uses a mixture of magnesium dialkoxide and magnesium sulfate as the magnesium compound, the polymerization activity is synergistically improved compared to conventional magnesium dialkoxide alone, and furthermore, the catalyst uses a mixture of magnesium dialkoxide and magnesium sulfate. By modifying the magnesium compound with (1) a silicon halide or organic compound, or (2) a silicon halide or organic compound and alcohol, the polymerization activity and the bulk specific gravity of polyethylene are further dramatically improved.

Therefore, according to the method of the present invention, high-quality polyethylene can be produced extremely efficiently and economically, and therefore, the method of the present invention is effective as a process for producing high-density polyethylene.

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

Example 1 (1) Preparation of catalyst 21.0 Mg(OC2H5) in 50 ml of n-heptane
g (8.8 mmol), commercially available anhydrous MgSO4 1.06
g (8.8 mmol) and further SiCl40
．． 75 g (4.4 mmol) was added and the reaction was carried out at 80° C. for 1 hour.

Next, 45 ml (45 mmol) of TiCl was added to
The reaction was carried out at ℃ for 3 hours.

After the reaction, the temperature was lowered, the mixture was allowed to stand, and the supernatant liquid was removed by a decanting method.

Add 100ml of n-heptane, stir, and let stand.
A washing operation for removing the supernatant liquid was performed three times.

Furthermore, 200 ml of n-heptane was added and the solid catalyst component (
A dispersion liquid of A) was obtained.

The amount of titanium supported was determined by the colorimetric method and was 42 mg-Ti/
g carrier.

(2) Polymerization of ethylene Thoroughly dry a 1 liter autoclave, add 400 ml of hexane, 2 ml of triethylaluminum, and dry under an argon stream.
．． 0 mmol and the above dispersion of the solid catalyst component (A) were introduced in an amount equivalent to 0.01 mmol as titanium atoms, and 8
The temperature was raised to 0°C.

Next, 3 kg/cm 2 of hydrogen and 5 kg/cm 2 of ethylene were added, and polymerization was carried out at 80° C. for 1 hour while maintaining the total pressure by replenishing ethylene.

Unreacted gas was purged, and the polymer was separated and dried to obtain 119 g of white polyethylene.

The polymerization activity was 248 kg per gram of titanium atom per hour.

Moreover, the bulk specific gravity of the polyethylene was 0.26, and the melt index (190° C., 2.16 kg load) was 0.83.

Comparative Example 1 (1) Production of catalyst 28.8 Mg(OC2H5) in 30 ml of n-heptane
mmol was suspended, further 45 mmol of TiCl was added, and the mixture was reacted at 98°C for 3 hours.

A dispersion of a solid catalyst component was produced in the same manner as in Example 1 (1).

The amount of titanium supported at this time was 250η-Ti/g-support.

(2) Polymerization of ethylene Example 1 (2
) Polymerization of ethylene was carried out in the same manner.

As a result, 16 g of polyethylene was obtained, the polymerization activity was 17 kg per hour per 1 g of titanium atom, and the tart index was 0.76.

Comparative Example 2 (1) Production of catalyst 496 mmol of MgSO was suspended in n-hepta/250 wLl, and 1,315 mmol of TiC was added and reacted at 98°C for 3 hours.

A dispersion of a solid catalyst component was produced in the same manner as in Example 1 (1).

The amount of titanium supported was 16 mg-Ti/g-support.

(2) Polymerization of ethylene Ethylene polymerization was carried out in the same manner as in Example 1 (2) except that 6 mmol of triethylaluminum and 2 mmol of the solid catalyst component prepared from the above-mentioned titanium atoms were used.

As a result, 80.8 g of polyethylene was obtained, the polymerization activity was 0.86 kg per hour per 1 g of titanium atom, and the melt index was 0.02.

Comparative Example 3 (1) Production of catalyst 260 Mg(OC2H5) in 7150 ml of n-hepta
mmol and 60 mmol of MgSO4 were suspended, the temperature was raised, 150 mmol of TiCl4 was added, and the mixture was reacted at 98°C for 3 hours.

In the following, a dispersion of solid catalyst components was produced in the same manner as in Example 1 (1), and the amount of titanium supported at this time was 110 mg-
It was a Ti/g-support.

(2) Polymerization of ethylene 8 mmol of triethylaluminum and the above 1(1)
Ethylene polymerization was carried out in the same manner as in Example 1 (2) except that the solid catalyst component prepared in 1 was used in an amount equivalent to 0.08 mmol in terms of titanium atoms.

As a result, 103 g of polyethylene was obtained, the polymerization activity was 27.3 kg per hour of titanium atoms 11, and the melt index was 18. Comparative Example 4 (1) Production of catalyst Mg (OC2H5)28.
8 mmol of SiCl was suspended, 48.8 mmol of SiCl was further added, and the reaction was carried out at 80° C. for 1 hour.

Next, 445 mmol of TiCl was added and reacted at 98° C. for 3 hours.

A solid catalyst component was produced in the same manner as in Example 1 (1).

The amount of titanium supported at this time was 106 mg-Ti/g per carrier.

(2) Polymerization of ethylene Ethylene polymerization was carried out in the same manner as in Example 1 (2) except that the solid catalyst component produced in (1) above was used.

As a result, 57 g of polyethylene was obtained, the polymerization activity was 1 g of titanium atom, 119 kg per hour, and the bulk specific gravity was 0.
22, the melt index was 5.1.

Example 2 (1) Production of catalyst A solid catalyst component was produced in the same manner as in Example 1 (1) except that Si(OC2H5)4 was used in place of SiC14.

The amount of titanium supported at this time was 20 mg-Ti/g-support.

(2) Ethylene polymerization Ethylene polymerization was carried out in the same manner as in Example 1 (2) except that the solid catalyst component produced in (2) above was used.

As a result, 135 g of polyethylene was obtained, the polymerization activity was 1 g of titanium atom, 270 kg per hour, and the bulk specific gravity was 0.
24, the melt index was 0.92.

Example 3 (1) Preparation of catalyst H--Mg (0”2H5)28 in 50 ml of heptane
, 8 mmol, MgSO 48.8 mmol were suspended;
In addition, 148.8 mmol of SiC, 35.2 mmol of ethanol
Millimoles were added and reacted at 80°C for 1 hour.

Next, 445 mmol of TiCl was added and reacted at 98°C for 3 hours.

A solid catalyst component was produced in the same manner as in Example 1 (1).

The amount of titanium supported at this time was 27 mg-Ti/g-support.

(2) Polymerization of ethylene Ethylene polymerization was carried out in the same manner as in Example 1 (2) except that the solid catalyst component produced in (1) above was used.

As a result, 145 g of polyethylene was obtained, the polymerization activity was 1 g of titanium atom, 302 kg per hour, and the bulk specific gravity was 0.
．． 33, and the melt index was 1.94.

Examples 4 to 7 The same experiments as in Example 3 were conducted except that the amounts of MgSO4, SiC14, or ethanol used were changed.

The results are shown in Table-1.

Examples 8 to 10 The same experiments as in Example 3 were conducted except that the type of silicon compound or alcohol was changed.

The results are shown in Table-2.

Claims (1)

[Claims] 1. A method for polymerizing ethylene using a catalyst containing (A) a reaction product of a magnesium compound and a titanium halide and (B) an organoaluminum compound,
A solid product obtained by contacting and reacting a mixture of magnesium dialkoxide and magnesium sulfate with a silicon halide or an organic compound and then reacting the resulting solid substance with a titanium halide is used as component (A). A method for polymerizing ethylene. 2. In a method of polymerizing ethylene using a catalyst containing (A) a reaction product of a magnesium compound and a titanium halide and (B) an organoaluminum compound,
As component (A), a solid product obtained by contacting and reacting a mixture of magnesium dialkoxide and magnesium sulfate with a silicon halide or an organic compound and alcohol, and then reacting the resulting solid substance with titanium halide is used. Characteristic ethylene polymerization method.