JPS584924B2 - Method for manufacturing polyolefin - Google Patents

Description

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

Conventionally, when producing polyolefins such as polyethylene, a magnesium compound such as magnesium halide or magnesium alkoxide is used as a catalyst carrier, and a catalyst made by reacting and supporting a titanium halide on the carrier has a higher performance than a simple Ziegler catalyst. known to be active.

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 obtained polyolefin 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. 47-43-4.35, Japanese Patent Publication No. 30118-1983), or magnesium alkoxide is treated with a halogenating agent. , a method of reacting with a titanium compound in the presence of an electron-donating compound, a halogenated silane, or a boron compound (Japanese Patent Publication No. 30118/1983, 32081/1981, 980/1980)
Improvement methods such as those disclosed in Japanese Patent Laid-open No. 76 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.0 The ultimate purpose of the methods for highly active polymerization of olefins 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 purpose is to improve quality, and the higher the catalyst activity, the more desirable it is.

From this point of view, the present inventors have conducted various studies on a method for producing polyolefin using a catalyst containing a reaction product of a modified compound of magnesium alkoxide and a titanium halide. The present invention was completed based on the discovery that the activity increases significantly when a solid material obtained by contacting with a specific amount of aluminum halide is further reacted with an alkyl aluminum compound, and then titanium halide is supported on the reaction product. reached.

That is, the present invention is based on (1) contacting magnesium alkoxide with aluminum halide in an amount of 0.4 to 9.0 moles per mole of the magnesium alkoxide in an alcohol solvent, and then reacting the solid product obtained with an alkyl aluminum compound; The present invention provides a method for producing a polyolefin, which comprises polymerizing an olefin using a product obtained by reacting with a titanium halide and (B) a catalyst containing an organoaluminum compound as an active ingredient.

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

Specifically, magnesium dimethoxide, magnesium diethoxide, magnesium dipropoxide, magnesium dibutoxide, magnesium dicyclohexoxide, magnesium dibenzoxide, etc. are suitable.

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

These magnesium alkoxides can be easily obtained by known methods.

On the other hand, examples of the aluminum halide used in the present invention include aluminum chloride, aluminum bromide, and aluminum iodide.

A solid product (
To obtain a modified magnesium alkoxide), first, the above magnesium alkoxide and aluminum halide are treated in alcohol.

Alternatively, magnesium, which is a raw material for magnesium alkoxide, may be brought into contact with aluminum halide while reacting with alcohol.

This treatment involves dissolving aluminum halide in alcohol and dispersing magnesium alkoxide or magnesium metal at temperatures ranging from 0 to 150°C, preferably from 20 to 100°C.
The test is carried out at 00°C for 15 minutes or more.

At this time, the addition ratio of magnesium alkoxide or magnesium metal to aluminum halide is preferably 0.4 to 9.0 moles of aluminum halide per mole of magnesium alkoxide or magnesium metal.

Even outside this range, the treatment effect with the aluminum alkyl described below can be obtained, but sufficient activity as a whole cannot be obtained (
(See reference example).

The alcohol used here is not particularly limited, but is usually a linear or side chain aliphatic alcohol having 1 to 8 carbon atoms, specifically methanol, ethanol,
Examples include n-propanol, 1-propanol, butanol, and ethanol is particularly preferred.

The amount of alcohol to be used is preferably selected so as to be in excess of the magnesium alkoxide and aluminum halide.

After the above contact treatment, the solvent alcohol is distilled off under heating and/or reduced pressure to obtain a solid product which is a precursor of a modified magnesium alkoxide.

The above solid product is then treated with an alkyl aluminum compound.

It is preferred that the solid product is previously mechanically pulverized prior to this treatment.

The pulverization can be carried out by conventional means, such as using a ball mill at room temperature for 0.5 to 10 hours.

The alkylaluminum compound used in this treatment has the formula AI RnX3-o (where X is a halogen atom, R
represents an alkyl group having 1 to 6 carbon atoms, and n represents an integer of 1 to 3.

) and aluminum sesquihalide, specifically triethylaluminum,
triisobutylaluminum, diethylaluminum monochloride, diisopropylaluminum chloride, diisobutylaluminum monochloride, ethylaluminum dichloride, isobutylaluminum dichloride,
Examples include ethylaluminum sesquichloride.

The amount of these alkyl aluminum compounds used is 0.01 to 4 (molar ratio), preferably 0.02 to 2 (molar ratio), relative to the amount of magnesium alkoxide used.

If the amount is less than this, the effect of improving the activity will not be sufficient, and if it is too much, it will be necessary to remove the excess amount of alkylaluminum compound, which may cause difficulties in the catalyst preparation operation, or increase the amount of high molecular weight during polymerization. Since polymers are easily formed, polymerization operations are particularly difficult in solution polymerization.

The treatment of a precursor of a modified magnesium alkoxide with an alkyl aluminum compound is carried out at a temperature of -10 to +1 in a hydrocarbon solution having 5 to 10 carbon atoms such as hexane or heptane.
Both are brought into contact with each other under stirring at 00°C, preferably 0 to 5°C, for 0.1 to 5 hours, preferably 0.5 to 2 hours.

The solid magnesium alkoxide modified product obtained by the above treatment is thoroughly washed and separated using a hydrocarbon solvent such as hexane or heptane, and then used for the titanium loading reaction.

Component (A) of the catalyst used in the present invention is obtained by reacting the above modified magnesium alkoxide with a titanium halide.

The reaction between the modified magnesium alkoxide and the titanium halide may be carried out in an inert solvent such as butane, pentane, hexane, heptane, cyclohexane, benzene, xylene, etc., or may be carried out without a solvent.

When the reaction is carried out in an inert solvent, the above-mentioned inert hydrocarbon is used as the solvent, the above-mentioned modified magnesium alkoxide is first dispersed therein, and then the titanium halide is added thereto, and while stirring, the The reaction is carried out at a temperature of 0.5 to 5 hours, preferably 30 to 150 degrees Celsius.

On the other hand, when the reaction is carried out without a solvent, the magnesium alkoxide modified product and the titanium halide may be directly mechanically mixed in a predetermined proportion using a ball mill or the like, and the reaction may be carried out.

The ratio of the magnesium alkoxide modified product and the titanium halide to be added in this reaction is not particularly limited, but preferably the titanium halide is added in an excess amount, specifically, in an amount of 1 to 20 times the molar amount relative to the magnesium alkoxide modified product.

The titanium halides that can be used here include tetravalent, trivalent, or divalent titanium halides, more specifically T+Br4, TI C]4, 'Tit.
(OR') Cl a,Tt(OR') CI2 ,T
i(OR')3Cl, T+Br3, TtCI3,
Ts Cl 2 etc. (where R' represents an alkyl group).

) can be given.

By carrying out the above reaction, a reaction product, which is a captive component of the catalyst used in the present invention, is obtained.

After the reaction is completed, free titanium compounds are removed from the reaction product by washing.

At this time, cleaning is performed using an inert hydrocarbon solvent having 5 to 10 carbon atoms,
For example, it is preferable to use pentane, hexane, cyclohexane, heptane, benzene, toluene, xylene, or the like.

The reaction product from which the free titanium compound has been washed away is further suspended in an inert solvent such as a hydrocarbon in an inert gas at an appropriate concentration to prepare a catalyst component.

Note that the washed reaction product may be further treated with organoaluminium and then made into a suspension in the same manner as above.

However, by omitting the organoaluminium treatment before titanium loading,
If only the organoaluminium treatment is performed after supporting titanium, the effects of the present invention cannot be obtained.

The method of the present invention is carried out using a catalyst containing the above-mentioned reaction product of a modified magnesium alkoxide and a titanium halide and an organoaluminum compound.

In polymerizing the olefin, a suspension of the above reaction product and an organoaluminum compound are added as a catalyst to the reaction system, and then the olefin 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 catalyst components added is 0.001 to 1.0 mmol/l for the reaction product of magnesium alkoxide modified product and titanium halide, while the amount of the organic aluminum compound is 0.001 to 1.0 mmol/l. 0.5-20
It is preferably mmol/L, particularly 1 to 10 mmol/L.

In addition, the olefin pressure in the reaction system is from normal pressure to 50 in the case of ethylene.
kg/cm' and the reaction temperature is preferably room temperature to 200°C.

Molecular weight adjustment during polymerization can be carried out by known means, such as hydrogen.

Examples of organoaluminum compounds which are component (B) of the catalyst used in the method of the present invention include trialkylaluminum compounds such as trimethylaluminum, triethylaluminum, triisopropylaluminum, triisobutylaluminum, trioctylaluminum, diethylaluminum monochloride, diisopropylaluminum, etc. Dialkyl aluminum monohalides such as aluminum monochloride, diisobutyl aluminum monochloride, dioctyl aluminum monochloride and the like are preferred.

The types of polyolefins that can be polymerized by the method of the present invention are:
Examples include homopolymers of α-olefins such as ethylene, propylene, 1-butene, and 1-hexene, as well as copolymers of these olefins and small amounts of other α-olefins.

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

The method of the present invention using the above-mentioned catalyst has a significantly high catalytic activity, so the reaction efficiency is high, and the resulting polyolefin has a high bulk density.

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

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

Example 1 Preparation of component (A) In 50 ml of ethanol, 10 g (75 mmol) of aluminum chloride, 10 g (88 mmol) of magnesium diethoxide
After 60 minutes of reaction under reflux, ethanol was distilled off by heating, and the mixture was vacuum-dried at 120° C. for 6 hours.

The resulting solid was ground in a ball mill at room temperature for 60 minutes.

The thus obtained solid II was mixed with 30 ml of normal heptane.
diethylaluminum monochloride 2 at room temperature.
mmol was added and stirred for 60 minutes.

After completion, the solution was washed with normal heptane until no aluminum compound was observed in the washing solution, and finally 50 ml of normal heptane was added to form a suspension.

Next, 4 ml of TI CI4 was added to the suspension and heated to 100°C.
The mixture was allowed to react for 3 hours.

After the reaction is completed, 3
The mixture was washed twice, and finally 200 ml of n-heptane was added to form a suspension of the catalyst component (A).

The amount of titanium supported on this supported catalyst was 14 mg/g carrier.

Polymerization of ethylene 400 ml of normal heptane, 2 mmol of triethylaluminum, and 0.0 ml of the above-mentioned supported catalyst as titanium.
004 mmol was introduced into a 1 l autoclave and 80
The temperature was raised to ℃, the ethylene pressure was 5 kg/cm'G, and the hydrogen pressure was 3 kg.
Continuously supply ethylene at /cm'G and polymerize for 1 hour to give 6
7 g of polyethylene was obtained.

The polymerization activity per 1 g of titanium, 1 hour, and 1 kg/cm'G of ethylene was 70 kg, and the melt index of polyethylene was 1.70 (190° C., 216 kg).

Example 2 26.2g of aluminum chloride in Example 1? 1
Component (A) of the catalyst was produced under the same conditions as in Example 1, except that 310 mmol of AI(C2H5)3CI was used as the organic aluminum compound.

The amount of titanium supported on this supported catalyst was 18 mg/g carrier.

400 ml of normal heptane, 2.0 mmol of triethylaluminum, and 0.0065 mmol of titanium as the supported catalyst were introduced into a 1-liter autoclave, and the temperature was raised to 80°C.

Polymerization was carried out at 80° C. for 1 hour while continuously supplying ethylene at a hydrogen pressure of 4 kg/cmG and ethylene of 4 kg/cm'G to obtain 52p polyethylene.

The polymerization activity per 1 g of titanium, 1 hour, and 1 kg/cm'G of ethylene was 41 kg, and the melt index of polyethylene was 3.2.

Example 3 In the same manner as in Example 1, a catalyst was prepared using 100 ml of ethanol, 52.4 g (584 mmol) of aluminum chloride, and 88 mmol of ethylaluminum dichloride as the organic aluminum compound, and polymerization was carried out.

In this case, the amount of titanium supported was 25 μg/g carrier, the polymerization activity per 1 g of titanium, 1 hour, and 1 kg/cm'G of ethylene was 58 kg, and the tart index of polyethylene was 2.40.

Example 4 In Example 1, magnesium metal was substituted with 1.8 2. magnesium diethoxide. A catalyst was prepared and polymerized in the same manner as in Example 1, except that p (75 mm IJ mol) was used, the reflux time was increased to 120 minutes, and ethylaluminum dichloride was used in place of diethylaluminium monochloride.

The amount of titanium supported on this supported catalyst was 32 mg/g carrier, the number of polymerized active groups per 1 g of titanium, 1 hour, and 1 kg/cm'G of ethylene was 77 kg, and the melt index of polyethylene was 1.30.

Comparative Example 1 In Example 1, the organoaluminum treatment was carried out after supporting Chikun to prepare a catalyst component.

The amount of titanium supported on this motsu was 28 mg/g carrier.

Ethylene polymerization was carried out using this catalyst under the same conditions as in Example 1.

As a result, the polymerization active area of this catalyst was 27.8 kg per 1 g of titanium, 1 hour, and 1 kg/cm' of ethylene.

Comparative Example 2 A supported catalyst was produced in Example 1 without adding aluminum chloride, and the amount of titanium supported was 92 mg/g of support.

400 ml of normal heptane, 2.0 mmol of triethylaluminum, and 0.0 mmol of the above supported catalyst as titanium.
4 mmol was introduced into a 1 liter autoclave and the hydrogen pressure was 3
kg/cm G, ethylene 124 by polymerizing at 80°C for 1 hour while continuously supplying ethylene at 5 kg/cmG.
g of polyethylene was obtained.

The polymerization activity per 1 g of titanium, 1 hour, and 1 kg/cm'G of ethylene was 12.3 kg, and the melt index of polyethylene was 5.3.

Reference Examples 1-8 The amount of aluminum chloride in Example 1 (Reference Examples 6-8
Catalyst production and ethylene polymerization were carried out in the same manner as in Example 1 except that the amount of metallic magnesium was varied and the organoaluminum treatment was not performed.

Claims (1)

[Claims] 1(A) Magnesium alkoxide in an alcohol solvent in an amount of 0.4 to 1 mole of the magnesium alkoxide.
A product obtained by reacting a solid product obtained by contacting with 9.0 mol of aluminum halide with an alkyl aluminum compound and then reacting with titanium halide, and (B) a catalyst containing an organoaluminum compound as an active ingredient. A method for producing a polyolefin, which comprises polymerizing an olefin using.