KR100436494B1 - A preparing method of supported catalyst for polymerization of ethylene homopolymer and ethylene/alpha-olefin copolymer - Google Patents

Abstract

The present invention relates to a process for preparing a supported catalyst useful for ethylene polymerization and ethylene / α-olefin copolymerization.

The method of the present invention is an organic magnesium compound, an organic chlorine compound and a silicon compound having a composition of MgPh ₂ .nMgCl ₂ .mR ₂ 0 (where n = 0.37 to 0.7; m ≧ ₁ ; R ₂ 0 = ether; Ph = phenyl) And a magnesium-containing carrier obtained by reacting the mixture at a molar ratio of organochlorine compound / Mg ≧ 0.5 at a temperature of −20 to 80 ° C. at a molar ratio of silicon compound / Mg ≧ 0.001 with a titanium compound active material.

Description

A preparing method of supported catalyst for polymerization of ethylene homopolymer and ethylene / alpha-olefin copolymer}

The present invention relates to a process for preparing a catalyst for use in ethylene polymerization and copolymerization of ethylene and α-olefin, and more particularly, a supported catalyst comprising a titanium compound on a magnesium-containing carrier having a narrow particle size distribution. It relates to a method of manufacturing).

By a method of coating a transition metal compound on a carrier, that is, an organic having a composition of MgPh ₂ .nMgCl ₂ .mR ₂ O, wherein Ph = phenyl; n = 0.37 to 0.7; m ≧ ₂ ; R ₂ O = ether After reacting a magnesium compound with an organic halide, a method of preparing a supported catalyst for ethylene polymerization and copolymerization of ethylene and α-olefin by coating a transition metal compound such as TiCl ₄ , VCl ₄ or VOCl ₃ on the obtained carrier is provided. It was filed by the applicant of the invention (Japanese Patent No. 330675/1995).

The catalyst prepared by the above known method, in particular, a catalyst prepared by coating TiCl ₄ on a carrier, has a wide molecular weight distribution even though the polymerization process is partially improved by preparing a polymer having a narrow particle size distribution and an increased apparent density. High initial activity and particle size control is difficult.

For polymers with narrow molecular weight distribution, especially linear low density polyethylene products produced by copolymerization of ethylene and α-olefins, narrow molecular weight distribution reduces the content of low molecular weight polymers that can be extracted by hexane in the product. It is known that it can be improved.

The polymerized polymer particles should be easy to control the particle size depending on the stability of the polymerization process and the intended use of the product. It is well known that polyethylene particles of particularly suitable size have a great influence on the particle transport by air of the particles in the post-polymerization process and on the productivity of the extruder.

For the above purpose, a technique for a catalyst having a uniform activity point capable of narrowing the molecular weight distribution and a technique for controlling the particle size of the polymer according to the needs of the product and the polymerization process are required.

An object of the present invention is to enable the preparation of polymers having a narrow molecular weight distribution and increased apparent density, and to improve the productivity of the polymerization process by slurry and gas phase polymerization and to easily control the polymer particle size according to the use of the polymerized product. It is to provide a method for producing a catalyst for polymerization and ethylene / α-olefin copolymerization.

In the catalyst preparation method of the present invention, the organic magnesium compound MgPh ₂ .nMgCl ₂ .mR ₂ O (where n = 0.37 to 0.7; m≥1: R ₂ O = ether; Ph = phenyl) The carrier obtained by reacting with the mixture is characterized by treating with a titanium compound.

The present invention will be described in detail as follows.

In the catalyst preparation method of the present invention, the organic magnesium compound complex [MgPh ₂ .nMgCl ₂ .nR ₂ O] in the production step of the magnesium-containing carrier is chlorobenzene, ether (R ₂ O) or a mixture of chlorobenzene and ether, chlorobenzene and It is used in the form of a solution dissolved in a mixture of aliphatic or aromatic compounds. The organic magnesium compound in the solution state is reacted with the organic chlorine compound and the silicon compound at a molar ratio of organic chlorine compound / Mg ≧ 0.5 and 0.1 ≧ silicon compound / Mg ≧ 0.001 at -20 to 80 ° C. in a hydrocarbon solvent to form a powdered organic magnesium compound. A carrier suspended in this hydrocarbon solvent is produced. Preferably, the silicon ethoxide is prepared by mixing silicon ethoxide and carbon tetrachloride in a molar ratio of 0.1> silicon compound / Mg> 0.001 and carbon tetrachloride in a molar ratio of organic chlorine compound / Mg ≧ 0.5. The carrier obtained by this method has a narrow particle size distribution. The size of the carrier and the catalyst particles can be adjusted to 5 ~ 150㎛ by the molar ratio of the silicon compound / Mg and the reaction conditions of the organic magnesium compound and the organic chlorine compound. The magnesium-containing carrier obtained as described above mainly contains magnesium dichloride (80 to 90% by weight), ether (7 to 15% by weight), silicone (less than 1% by weight) and hydrocarbon complex (1 to 5% by weight). .

The organomagnesium compound used in the preparation of the magnesium containing carrier in the present invention is prepared by reacting powdered magnesium with chlorobenzene in the presence of one or more electron donor compounds. At this time, the electron donor may include aliphatic ether and cyclic ether. Aliphatic ethers are those having the structure of R ₂ OR ₃ wherein R ₂ and R ₃ are the same or different alkyl radicals of 2 to 8 carbon atoms, and are preferably aliphatic ethers of 4 to 5 carbon atoms. The cyclic ether is a cyclic ether having 3 to 4 carbon atoms. Most preferred as electron donor is dibutyl ether or diisoamyl ether.

As the organic chlorine compound used in the present invention, a compound of the general formula CR ' _n Cl _(4-n) wherein R' is an alkyl radical having 1 to 12 carbon atoms (where n is an integer of 0 to 3) is used. Preferred organochlorine compounds are carbon tetrachloride.

The silicon compound used in the present invention has a general formula of Si (OR) _a X _4-a . R is an aliphatic hydrocarbon group having 1 to 14 carbon atoms, X is Cl, Br or I, and a is 0, 1, 2, 3 or 4. Preferred silicon compounds are silicon alkoxides, examples of which are Si (OC ₂ H ₅ ) ₄ , Si (OC ₂ H ₅ ) ₂ Cl ₂ , Si (OC ₂ H ₅ ) Cl ₃ , Si (OC ₂ H ₅ ) ₃ There is Cl.

The organic chlorine compound and the silicon compound may be reacted with the organic magnesium compound in the following three ways to prepare a carrier. First, a method of mixing a silicon compound and an organic chlorine compound at a predetermined ratio before the reaction and then reacting with the organic magnesium compound. Second, after the organic chlorine compound and the organic magnesium reacts first, after a certain time, the mixed solution of the silicon compound and the organic chlorine compound in a certain ratio is reacted with the organic magnesium. Third, after the silicon compound is fed to the organic magnesium mixture before the reaction, the organic chlorine compound and the organic magnesium react. The first of the three methods is most preferred.

In the catalyst of the present invention, the magnesium-containing carrier prepared as above is used as a titanium compound in a hydrocarbon solvent at a molar ratio of Ti / Mg = 0.01 to 2.0, preferably 0.04 to 0.5, 20 to 100 캜, preferably 40 to 80 캜. It is obtained by processing at the temperature of.

If necessary, the catalyst is a titanium compound in which the magnesium-containing carrier prepared as described above is a titanium compound in which a silicon compound is mixed, and in a molar ratio of Si / Ti = 0.1 to 2.0, preferably 0.5 to 1.0, Ti / Mg = 0.01 to 2.0, preferably Can be obtained by treating at a temperature of 20 to 100 캜, preferably 40 to 80 캜 in a hydrocarbon solvent at a molar ratio of 0.04 to 0.5.

The titanium compound used in the present invention has a general formula of Ti (OR) _a X _4-a . R is an aliphatic hydrocarbon group having 1 to 14 carbon atoms, X is Cl, Br or I, and a is 0, 1, 2 or 3. Preferred titanium compounds are titanium tetrachloride and titanium alkoxychlorides, examples of which are TiCl ₄ , Ti (OC ₃ H ₇ ) ₂ Cl ₂ , Ti (OC ₃ H ₇ ) Cl ₃ , Ti (OC ₃ H ₇ ) ₃ Cl, Ti (OC ₄ H ₉ ) ₂ Cl ₂ , Ti (OC ₄ H ₉ ) Cl ₃ , Ti (OC ₄ H ₉ ) ₃ Cl.

If the Ti / Mg molar ratio is higher than 2.0, it is generally necessary to remove the excess titanium compound which is not fixed on the support (carrier) in the catalyst washing process, and the high cost of waste treatment due to the toxicity and corrosiveness of the removed titanium compound There is difficulty holding it. In addition, when the Ti / Mg molar ratio is lower than 0.01, there is a problem that the activity is not sufficient.

After the titanium treatment or after the preparation of the catalyst, if necessary, the molar ratio of Al / Ti may be 0.1 to 2.0, and the organic aluminum compound may be treated before washing. Preferably, the molar ratio of Al / Ti is set to 0.5 to 1.5 and treated at a temperature of 30 to 80 占 폚. The use of excess organoaluminum has the disadvantage that the carrier is broken down to produce fine particles. As the organoaluminum compound used herein, an organoalkylaluminum aluminum or organoaluminum halogen compound having a structure of AlR ' _n X _(3-n) is used. R 'means an alkyl group containing 1 to 16, more preferably 2 to 12 carbon atoms, X represents a halogen compound such as chlorine and bromine, and n is an integer or fraction of 0 to 3. Such organoaluminum compounds include triethylaluminum, triisobutylaluminum, trihexylaluminum, trioctylaluminum, ethylaluminum chloride, methylaluminum chloride, ethylaluminum sesquibromide, isobutylaluminum sesquichloride, dimethylaluminum chloride and diethyl Aluminum chloride, diethylaluminum bromide, diethylaluminum iodide, dinormalpropylaluminum chloride, dinormalylaluminum chloride, diisobutylaluminum chloride, dinomaloctylaluminum iodide, methylaluminum dichloride, ethylaluminum dichloride , Isobutyl aluminum dichloride, normal butyl aluminum dichloride and the like. Preferred organoaluminum compounds are selected from dialkylaluminum chlorides or from ethylaluminum sesquichlorides.

As described above, the method for preparing a catalyst of the present invention has a narrow particle size distribution and various average particle sizes, and provides a method for preparing a high activity catalyst that can be used for various purposes.

For example, according to the present invention, a catalyst having a particle size of 5 to 10 탆 and a particle size of 10 to 15 탆 useful for slurry ethylene polymerization can be prepared, and a catalyst having a particle size of 25 to 150 탆 useful for gas phase ethylene polymerization. Can be prepared. When using a mixture of silicon compounds as a component of the carrier, polyethylene having a relatively narrow molecular weight distribution is obtained than using only a magnesium carrier to which the silicon compound is not added. The narrow molecular weight distribution (MWD) is characterized by a molecular weight distribution <6 measured by gel permeation chromatography, and the titanium supported catalyst in which the silicon compound according to the present invention is mixed is polyethylene of 2.5 <MWD <4 and It is suitable for obtaining a polyethylene copolymer.

The catalyst according to the invention is used for ethylene polymerization or copolymerization of ethylene and α-olefins. The catalyst of the present invention may be used together with one or more organoaluminum compounds, preferably trialkylaluminum as cocatalyst.

The organoaluminum compound usable as a cocatalyst has a structural formula of AlR _n X _3-n . Wherein R is an alkyl radical having 1 to 12 carbon atoms, X is a hydrogen atom or a halogen atom such as chlorine or fluorine or an alkoxy radical having 1 to 12 carbon atoms, and n is an integer or fraction of 1 to 3; As examples, tri-isobutylaluminum, triethylaluminum, trimethylaluminum, tri-n-hexylaluminum, tri-n-octylaluminum, ethylaluminum sesquichloride or diethylaluminum chloride can be used.

The polymerization may be carried out by slurry polymerization at a temperature of 50-100 ° C. in a hydrocarbon solvent (eg, hexane, heptane) or by gas phase polymerization at a temperature of 60-120 ° C. and a pressure of 2-40 atmospheres in the absence of a hydrocarbon solvent. Performed by law. Hydrogen (5-90% by volume) is used as the molecular weight regulator of the polymer. Propylene, butene-1, hexene-1, 4-methylpentene-1 and other α-olefins are useful for the copolymerization of ethylene with α-olefins.

Hereinafter, the present invention will be described in detail through Examples and Comparative Examples. However, the following examples do not limit the content of the present invention.

Comparative Example 1

<A> Preparation of Organic Magnesium Compound

In a 1 L glass reactor equipped with a stirrer and a temperature controller, 29.2 g of magnesium powder (1.2 mol) in the presence of 307 ml of dibutyl ether (1.8 mol) and 0.29 g of iodine dissolved in 4 ml butyl chloride as an activator And 436 ml of chlorobenzene (4.3 mol) were reacted. The reaction proceeded with stirring for 10 hours under an inert gas atmosphere (nitrogen) at a temperature of 80-100 ° C. The reaction mixture was then left for 12 hours without stirring and the liquid phase was separated from the precipitate. Liquid phase MgPh ₂ .0.5MgCl a ₂ .2 (C ₄ H ₉₎ the solution is dissolved in the organic magnesium compound having a composition of ₂ O chlorobenzene (the concentration of Mg is 0.92mol per 1ℓ).

<B> Carrier Synthesis

120 ml (0.11 mol Mg) of the solution obtained in <A> was introduced into a reactor equipped with a stirrer, and 10.6 ml CCl ₄ (0.11 mol CCl ₄ ) dissolved in 42 ml of n-hexane was added at a temperature of 50 ° C. It was added into the reactor over time. The reaction mixture was stirred at the same temperature for 6 minutes, then the solvent was removed, and the precipitate was washed four times at 60 ° C. with 100 ml of n-hexane. As a result, 11.8 g of powdered organomagnesium carrier was obtained in a state suspended in n-hexane.

<C> Preparation of Catalyst

Titanium alkoxy chloride prepared by mixing 1.5 ml of TiCl ₄ and 3.8 ml of titanium propoxide (Ti (OC ₃ H ₅ ) ₄ ) to the n-hexane suspension of the obtained organic magnesium carrier to have a Ti / Mg molar ratio = 0.25. The reaction mixture was added and heated to 60 ° C., and then stirred for 2 hours to wash the solid precipitate obtained at 60 ° C. four times with 100 ml n-hexane. The average particle size of the catalyst was 55 μm.

<Polymerization>

The polymerization of ethylene was carried out in a 2 L steel reactor equipped with a stirrer and temperature control jacket. N-hexane (1000 mL) was used as a hydrocarbon solvent, and 2 mmol of Al (Et) ₃ was used as a promoter. The polymerization was carried out for 1 hour at a temperature of 80 ° C. under ethylene pressure of 7.5 atm and hydrogen pressure of 4.5 atm.

A catalyst corresponding to 0.015 mmol Ti was taken for the experiment, and the catalytic activity was 12.5 kg polyethylene per catalyst gTi, per unit time, per unit ethylene pressure. The polyethylene melt index (MI) was 8.9g / 10min at a load of 2.16kg and a temperature of 190 ° C. The melt index of 21.6kg and 2.16kg was 30. The apparent density of the polyethylene powder was 0.32 g / cm 3 and showed a narrow particle size distribution. From the powder analysis data, the SPAN value calculated by the following equation was less than 0.6. The ethylene polymerization results are shown in Table 1.

SPAN = (d90-d10) / d50, where d90, d50 and d10 mean polyethylene particle sizes such that the total particle content is 90, 50 and 10% by weight, respectively.

Example 1

Comparative Example 1 Instead of reacting the organic magnesium compound with 10.6 ml CCl ₄ (0.11 mol CCl ₄ ) dissolved in 42 ml of n-hexane, 10.6 ml of CCl ₄ and 1.5 ml (0.007 mol) of silicon ethoxy were reacted. A catalyst was prepared in the same manner as in Comparative Example 1 except that the mixture prepared by mixing the side (Si (OC ₂ H ₅ ) ₄ ) was added such that the CCl ₄ / Mg molar ratio = 1.0 and the Si / Mg molar ratio = 0.06. Ethylene polymerization was carried out in the same manner as in Comparative Example 1. The ethylene polymerization results are shown in Table 1.

Example 2

Example 1 Carrier manufacturing titanium propoxide of TiCl ₄ and the like 3.8㎖ 1.5㎖ as 0.03 the Si / Mg ratio in the _{(Ti (OC 3 H 5)} 4) mixture instead of using a TiCl ₄ in 3.0㎖ A catalyst was prepared in the same manner as in Example 1. Ethylene polymerization was carried out in the same manner as in Example 1. The ethylene polymerization results are shown in Table 1.

Example 3

1-hexene copolymerization was carried out using the catalyst obtained in Example 2. The polymerization was carried out in the same manner as in Example 1 except that 150 cc of 1-hexene was used before the polymerization. As a result of polymerization, ethylene and 1-hexene copolymer having a density of 0.945 g / cc was prepared. The ethylene copolymerization results are shown in Table 1.

activation* Si / Mg Catalyst Average Particle Size MI 2.16 ** MFRR *** Apparent density Span ratio Example 1 11.20 0.06 40 12.1 30.4 0.34 <0.6 Example 2 28.46 0.03 53 14.9 25.1 0.34 <0.6 Example 3 15.95 0.03 53 21.7 25.0 0.38 <0.6 Comparative Example 1 12.50 0.00 65 8.9 30.0 0.32 <0.6

* Unit: Kg-PE / gTi.ethylene 1 atm.hr

** MI 2.16: Melt index at load of 2.16kg and temperature of 190 ℃

MI 21.6: Melt index at load of 21.6Kg and temperature of 190 ℃

*** MFRR: MI 21.6 / MI 2.16 Ratio

As described above, the method for preparing a catalyst of the present invention provides a high activity catalyst having various average particle sizes based on the molar ratio of the organosilicon compound and magnesium, and at the same time, a polyethylene resin having a narrow molecular weight distribution having a narrow particle size distribution.

Claims (10)

MgPh ₂ .nMgCl ₂ .mR ₂ O (wherein Ph = phenyl, n = 0.37 to 0.7; m ≧ ₁ ; R ₂ 0 = ether), an organic magnesium compound, an organic chlorine compound, and a general formula Si (OR) _a A mixture of silicon compounds of X _4-a , wherein R is an aliphatic hydrocarbon group having 1 to 14 carbon atoms, X is Cl, Br or I, and a is 0, 1, 2, 3 or 4; At a temperature of &lt; RTI ID = 0.0 &gt; C, &lt; / RTI &gt; the molar ratio of organic chlorine compound / magnesium is 0.5 or more and the silicon compound / magnesium molar ratio is 0.001 to 0.1, and then the obtained magnesium-containing carrier is reacted with the general formula Ti (OR) _a X _4-a (where R Is an aliphatic hydrocarbon group having 1 to 14 carbon atoms, X is Cl, Br or I, and a is 0, 1, 2, or 3). Method for producing a supported catalyst for copolymerization of. The supported catalyst for ethylene polymerization and copolymerization of ethylene and α-olefin according to claim 1, wherein the organomagnesium compound is prepared by the reaction of metal magnesium with chlorobenzene in the presence of dibutyl ether or diisoamyl ether. Manufacturing method. The ethylene compound according to claim 1, wherein the organochlorine compound is a compound of the general formula CR'Cl _(4-n) , wherein R 'is an alkyl radical having 1 to 12 carbon atoms and n is an integer of 0 to 3 Process for preparing supported catalyst for polymerization and copolymerization of ethylene and α-olefin. The method for preparing a supported catalyst for ethylene polymerization and copolymerization of ethylene and α-olefin according to claim 3, wherein the organic chlorine compound is carbon tetrachloride. delete The method for preparing a supported catalyst for ethylene polymerization and copolymerization of ethylene and α-olefin according to claim 5, wherein the silicon compound is silicon alkoxychloride. delete 8. The method for preparing a supported catalyst for ethylene polymerization and copolymerization of ethylene and α-olefin according to claim 7, wherein the titanium compound is titanium alkoxychloride or titanium chloride. The method for preparing a supported catalyst for ethylene polymerization and copolymerization of ethylene and α-olefin according to claim 1, wherein the molar ratio of Ti / Mg when the magnesium-containing carrier is treated with a titanium compound is 0.01 to 2.0. delete