KR20190055465A - Method for producing catalyst for polymerization of ethylene and method for producing polyethylene using the same - Google Patents

Abstract

The present invention relates to a method for manufacturing a catalyst for polyethylene polymerization and a method for manufacturing polyethylene using the same. Specifically, the present invention relates to: the method for manufacturing the catalyst for polymerization of polyethylene for a chlorinated polyethylene raw material which can exhibit a high catalytic activity in a polyethylene synthesis reaction, and in which a synthesized polyethylene has a small particle size and narrow particle distribution and distribution of molecular weight can be easily controlled, thereby being able to manufacture chlorinated polyethylene excellent in mechanical properties; and the method for manufacturing polyethylene using the same.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to a method for producing a polyethylene-based catalyst, and a method for producing the same. BACKGROUND ART < RTI ID = 0.0 >

The present invention relates to a process for preparing a catalyst for the polymerization of polyethylene and a process for producing polyethylene using the same. More particularly, the present invention relates not only to a high catalytic activity in a polyethylene synthesis reaction, but also to a chlorinated polyethylene which can produce chlorinated polyethylene having a small particle size, narrow particle distribution and easy control of molecular weight distribution, To a process for producing a catalyst for polymerization of polyethylene for raw materials and a process for producing polyethylene using the same.

Polyethylene is classified into low-density polyethylene and high-density polyethylene depending on its density and performance. High-density polyethylene is excellent in softening point, hardness, strength and electrical insulation, and is used mainly in various containers, packaging films, fibers, pipes, packings, and insulating materials. These high density polyethylene chlorinated by treatment with chlorine is called chlorinated polyethylene and is widely used as an impact modifier for PVC pipe and building exterior materials because it has excellent chemical resistance, weather resistance, flame retardancy, workability and impact strength reinforcement effect. In order to provide chlorinated polyethylene excellent in compatibility with PVC and excellent impact-strengthening performance and greatly shortening the plasticizing time, it is required that the chlorine distribution uniformity in the high-density polyethylene should be excellent. The size and molecular weight distribution of high-density polyethylene is an important factor determining the chlorine distribution of chlorinated polyethylene.

On the other hand, the catalyst used for producing polyethylene can be divided into a Ziegler-Natta catalyst, a Cr-based catalyst and a metallocene catalyst depending on the kind of the central metal to be applied. These catalysts have been selectively used according to the requirements of the production process and the application product because of different catalytic activity, hydrogen reactivity, molecular weight distribution, and reaction characteristics to comonomers. Among them, Ziegler-Natta catalysts containing magnesium are most widely used in the production of polyethylene polymers because they have advantages in terms of high activity, operation stability, excellent physical properties and economical efficiency compared to other catalysts. However, since the Ziegler-Natta catalyst is a multi-active catalyst having a plurality of active sites, the particle size distribution and the molecular weight distribution of the polymer are wide, and the composition distribution of the comonomer is not uniform, have.

U.S. Patent No. 6,225,428 discloses a method of controlling the molecular weight and molecular weight distribution of a polymer by using a metallocene catalyst supported on each carrier, but it has a disadvantage in that the production method of the catalyst is complicated and the molecular weight distribution is wide.

U.S. Patent No. 9,644,050 discloses a method of controlling the particle size of a catalyst using a Ziegler-Natta catalyst having an internal electron donor introduced therein, but there are limitations in obtaining a polymer particle having a complicated and low-particle size, which is a catalyst production method.

Korean Patent Application No. 2014-0140957 discloses a method of controlling the molecular weight distribution using a metallocene catalyst, but it has a disadvantage in that the molecular weight distribution during the formation of the chlorinated polyethylene is so narrow that the moldability is poor and the plasticization time is long .

Therefore, there is a need to develop a catalyst for the polymerization of polyethylene capable of producing polyethylene having excellent activity, small particle size and desired physical properties in order to solve the above disadvantages.

U.S. Patent No. 6,225,428 U.S. Patent No. 9,644,050 Korean Patent Application No. 2014-0140957

The present invention relates to a method for preparing a catalyst for polyethylene polymerization having a small particle size and uniform particle size distribution by introducing an internal electron donor in the process of preparing a catalyst for polyethylene polymerization. The polyethylene synthesized therefrom has high polymerization activity and easy control of molecular weight distribution Which is capable of producing chlorinated polyethylene having excellent mechanical properties. The present invention also provides a method for producing a catalyst for polymerization of polyethylene.

The present invention

(A) dissolving a magnesium compound in a solvent containing a first hydrocarbon solvent having 5 to 25 carbon atoms and an alcohol to prepare a magnesium compound solution;

(B) reacting the magnesium compound solution with a compound represented by the following formula (1); And

(C) reacting the product of step (B) with a transition metal compound in the presence of a second hydrocarbon solvent having 6 to 25 carbon atoms.

[Chemical Formula 1]

In Formula 1,

R ₁ is selected from the group consisting of hydrogen, linear or branched alkyl having 1 to 20 carbon atoms, alkenyl having 2 to 20 carbon atoms, cycloalkyl having 3 to 20 carbon atoms, aryl having 6 to 20 carbon atoms Alkylsilyl having 1 to 20 carbon atoms, alkylsilyl having 7 to 20 carbon atoms, or alkyl having 2 to 20 carbon atoms containing a hetero atom.

The present invention also provides a catalyst for polyethylene polymerization comprising a magnesium compound, a transition metal compound and a compound of the above formula (1).

The present invention also provides a process for producing polyethylene comprising the step of synthesizing an ethylenic monomer in the presence of the catalyst for the polymerization of polyethylene.

According to the present invention, there is provided a process for producing a polyethylene polymerization catalyst capable of producing chlorinated polyethylene having excellent mechanical properties by controlling not only a high activity and an apparent density in the polymerization reaction of polyethylene, but also a particle size and a distribution degree and a molecular weight distribution of the produced polyethylene And a method for producing polyethylene are provided.

The present invention

(A) dissolving a magnesium compound in a solvent containing a first hydrocarbon solvent having 5 to 25 carbon atoms and an alcohol to prepare a magnesium compound solution;

(B) reacting the magnesium compound solution with a compound represented by the following formula (1); And

(C) reacting the product of step (B) with a transition metal compound in the presence of a second hydrocarbon solvent having 6 to 25 carbon atoms.

[Chemical Formula 1]

In Formula 1,

R ₁ is selected from the group consisting of hydrogen, linear or branched alkyl having 1 to 20 carbon atoms, alkenyl having 2 to 20 carbon atoms, cycloalkyl having 3 to 20 carbon atoms, aryl having 6 to 20 carbon atoms Alkylsilyl having 1 to 20 carbon atoms, alkylsilyl having 7 to 20 carbon atoms, or alkyl having 2 to 20 carbon atoms containing a hetero atom.

The compound of Formula 1 is a carbonate compound, and it is possible to control the catalyst particle size, activity, bulk density, molecular weight distribution and the like according to the kind of the substituent group to which R ₁ of Formula 1 is introduced. Specific examples of the compound of Formula 1 include cyclopentylmethyl carbonate, cyclopentylethyl carbonate, cyclo-2-methylpropyl carbonate, and cyclopentyl 1,1-dimethylethyl carbonate.

The step of reacting the magnesium compound solution and the compound of Formula 1 in the step of preparing the magnesium compound solution may be performed at -10 ° C to 150 ° C.

The molar ratio of the magnesium compound to the compound of formula (1) may be 1: 0.01 to 1: 1, preferably 1: 0.05 to 1: 0.5. If it is out of the above range, the activity of the catalyst may be lowered by interfering with the formation of transition metal particles to be supported on the produced catalyst.

Specific examples of the magnesium compound include magnesium halide, dialkoxymagnesium, alkylmagnesium halide, alkoxymagnesium halide or aryloxymagnesium halide, and magnesium halide is more preferable because it increases the activity of the catalyst. In one embodiment, the magnesium compound is selected from the group consisting of magnesium halide, dialkoxymagnesium, alkyl magnesium halides of 1 to 20 carbon atoms, alkoxy magnesium halides of 1 to 20 carbon atoms, and aryloxy magnesium halides of 6 to 20 carbon atoms. Or more.

Specifically, the magnesium halide compound may be a compound having no reducibility such as magnesium chloride, magnesium dichloride, magnesium fluoride, magnesium bromide, magnesium iodide, phenoxy magnesium chloride, isopropoxymagnesium chloride, butoxy magnesium chloride, It is preferable to increase the activity of the catalyst. Among them, magnesium dichloride is preferably used because it exhibits stable and high activity in terms of structure and coordination with the transition metal compound, which is the main active metal.

The magnesium compound reacts with the alcohol to be completely dissolved, and the alcohol makes the crystal structure of the magnesium compound saturate so that the internal electron donor and the transition metal compound can be structurally stably coordinated.

In the step of preparing the magnesium compound solution, the molar ratio of the magnesium compound and the alcohol may be 1: 0.5 to 1:10. When the molar ratio of the alcohol to the magnesium compound exceeds 10 moles, the recrystallization reaction does not occur well and the amount of the transition metal compound to be reacted with the magnesium compound must be increased in order to exhibit high activity, If it is less than 0.5 mole, the magnesium compound is not dissolved well and a homogeneous solution of the magnesium compound can not be produced, which is not preferable.

The step of preparing the magnesium compound solution may be carried out at 60 to 150 ° C. That is, the dissolving temperature for dissolving the magnesium compound in alcohol is preferably 80 to 140 ° C., and if it is out of the above range, the magnesium compound is not easily dissolved in the alcohol or the side reaction is increased, which is not preferable.

The alcohol can be used without limitation as long as it is an alcohol known to be used in the production of a Ziegler-Natta catalyst for synthesizing polyethylene. Specific examples of the solvent include ethanol, n-propanol, isopropanol, n-butanol, isobutanol, n-pentanol, isopentanol, neopentanol, cyclopentanol, n- Aliphatic or alicyclic alcohols such as dodecanol, 2-methylpentanol, 2-ethylbutanol and 2-ethylhexanol; Aryl cyclic alcohols such as cyclohexanol and methylcyclohexanol; And aromatic alcohols such as benzyl alcohol, methylbenzyl alcohol, isopropylbenzyl alcohol and? -Methylbenzyl alcohol. Of these, aliphatic or alicyclic alcohols or alcohols having 2 or more carbon atoms are preferably used, and 2-ethyl- More preferably, 1-hexanol is used.

The step of preparing the magnesium compound solution may be carried out in a solvent of the first hydrocarbon. When the reaction is carried out in a hydrocarbon solvent, a homogeneous solution of a magnesium compound and an alcohol can be obtained while using a small amount of alcohol, which is preferable.

Specific examples of the first hydrocarbon solvent include aliphatic or alicyclic hydrocarbons having 5 to 25 carbon atoms, and most preferred are aliphatic or alicyclic hydrocarbon solvents having 6 to 17 carbon atoms. More specific examples include aliphatic hydrocarbons such as hexane, heptane, octane, decane, dodecane, tetradecane, and mineral oils having 5 to 25 carbon atoms (e.g., Cas No. 8042-47-5); Alicyclic hydrocarbons such as cyclic hexane, cyclic octane, methyl cyclic pentane and methyl cyclic hexane; And aromatic hydrocarbons such as benzene, toluene, xylene, ethylbenzene, and cumene.

If the amount of the first hydrocarbon solvent is too small or too large, it is difficult to control the catalyst particle size, and it may be difficult to control the transition metal compound and the donor supporting ratio. Therefore, it is appropriate that the first hydrocarbon solvent is used in an amount of 5 to 20 mol based on 1 mol of the magnesium compound. The amount of the first hydrocarbon solvent used is less than 5 mol based on 1 mol of the magnesium compound and the magnesium compound is not well dispersed. If the amount of the first hydrocarbon solvent is more than 20 mol, the catalyst particle diameter and the transition metal compound bearing ratio are low, .

After reacting the compound of Formula 1 and the magnesium compound solution, the catalyst may be reacted with a transition metal compound represented by Formula 2 below to produce a solid catalyst. Specific examples of the transition metal compound include any transition metal compound known to be used as a Ziegler-Natta catalyst for polyethylene polymerization and can be used in the production of the catalyst component without limitation. In particular, preferred examples of the transition metal compound include compounds represented by the following general formula (2).

(2)

MX _n (OR ₂ ) _4-n

In Formula 2,

M is selected from the group consisting of transition metal elements of groups IVB, VB and VIB of the periodic table,

X is halogen,

R ₂ is an alkyl group having 1 to 10 carbon atoms,

n is an oxidation number of the metal of 0 to 4;

Preferable examples of M include titanium, zirconium, hafnium, vanadium, niobium, tantalum, chromium, and molybdenum.

Specific examples of the transition metal compound represented by the above formula (2) include titanium tetrachloride, sabromium titanium, titanium tetraiodide, tetrabutoxy titanium, tetraethoxy titanium, diethoxy titanium dichloride, or ethoxy titanium trichloride. And it is preferable to use titanium tetrachloride.

The transition metal compound may be used in an amount of 0.01 to 10 mol based on 1 mol of the magnesium compound. If the amount of the transition metal compound used is less than 0.01 mol based on 1 mol of the magnesium compound, the activity of the transition metal compound may be lowered, and if the amount of the transition metal compound is more than 10 mol, Thereby reducing the pores in the catalyst, decreasing the activity, increasing the metal residual ratio in the polymer, and increasing the human hazard and environmental pollution.

The transition metal compound can be reacted by dispersing in a second hydrocarbon solvent. Specific examples of the second hydrocarbon solvent include aliphatic or alicyclic hydrocarbons having 5 to 25 carbon atoms, and aliphatic or alicyclic hydrocarbon solvents having 6 to 17 carbon atoms are preferred. More specific examples include aliphatic hydrocarbons such as hexane, heptane, octane, decane, dodecane, tetradecane, and mineral oils having 5 to 25 carbon atoms (e.g., Cas No. 8042-47-5); Alicyclic hydrocarbons such as cyclic hexane, cyclic octane, methyl cyclic pentane and methyl cyclic hexane; And aromatic hydrocarbons such as benzene, toluene, xylene, ethylbenzene, and cumene. It is more preferable to use hexane because the particle size distribution of the solid catalyst to be produced is uniform and the surface of the catalyst particle is a smooth spherical shape.

In one embodiment of the process of the invention, dilution with a second hydrocarbon solvent is used to adjust the particle size of the resulting catalyst. When the second hydrocarbon solvent is not added, the catalyst particle diameter may be as small as 1 占 퐉 or less, and when the second hydrocarbon solvent is added too much, the catalyst particle size may increase and the catalyst performance may deteriorate. The second hydrocarbon solvent used in the reaction is used in an amount of 3 to 20 mol or 5 to 10 mol based on 1 mol of the magnesium compound. When the amount of the second hydrocarbon solvent is more than 20 mol, the catalyst particle size is increased. In general, in the case of recrystallization catalyst, the transition metal distribution which acts as the pore volume and the active point varies depending on the catalyst particle size, and the apparent density of the polymer and the activity changes. As a result, the activity is lowered when the catalyst particle size is increased. Further, when the second hydrocarbon solvent is not used or when it is used in an amount of less than 3 mol, the catalyst is difficult to produce due to a small particle size of the catalyst and too many fine particles are formed after the production of the polymer.

In one embodiment of the invention, step (C) of the process can be carried out at from -20 to 0 < 0 > C. In one embodiment, the temperature may be between -15 and 0 ° C. The magnesium compound may be added to the transition metal compound maintained at the temperature. That is, the magnesium compound is added at a temperature of -20 to 0 ° C, and the catalyst particle size varies depending on the temperature at which the magnesium compound is added. When the magnesium compound is added at a temperature higher than 0 ° C, the catalyst particle size is small, the catalyst particle size distribution is widened, the catalyst hardness is lowered, the apparent density is lowered, and the generation of the fine particles may be increased. On the other hand, when the magnesium compound is added at less than -20 ° C, the catalyst particle size is large and the catalyst particle size distribution can be narrowed.

In one embodiment of the present invention, the dropping time of the magnesium compound is suitably 1 to 4 hours. If the charging time of the magnesium compound is less than 1 hour, the temperature rises due to a violent reaction, which widens the catalyst particle size distribution. If the charging time exceeds 4 hours, the catalyst particle size becomes large. When the particle size distribution of the catalyst is widened, the particle size distribution of the polymer produced after the polymerization is widened, the apparent density is lowered, and the operation conditions are difficult to form in the product molding, which leads to a disadvantage that the productivity is poor.

The present invention also provides a method for preparing a catalyst for polyethylene polymerization, which comprises, in addition to the above steps (A) to (C), (D) reacting with an alkylaluminium compound represented by the following formula (3)

(3)

R _3n AlX _3-n

In Formula 3,

R ₃ is an alkyl group having 1 to 8 carbon atoms,

X is halogen,

n is from 0 to 3;

The alkylaluminium compound can act as a cocatalyst and can form active sites by reducing the transition metal compound, thereby enhancing catalytic activity. In particular, when the transition metal compound is first reacted and the alkylaluminium compound is reacted, transition metal active sites can be more evenly distributed, so that polyethylene having a higher catalytic activity and a broad molecular weight distribution and improved processability can be produced.

Specific examples of such alkylaluminium compounds include triethylaluminium, trimethylaluminium, triisopropylaluminium, trioctylaluminium, diethylaluminium chloride, diethylaluminium bromide, diethylaluminium iodide, di Ethylaluminium fluoride, ethylaluminium dichloride, dimethylaluminium chloride, methylaluminum dichloride and the like can be used.

The molar ratio of the magnesium compound to the co-catalyst may be 1: 0.01 to 1:10, or 1: 0.01 to 1: 2. If the amount of the alkylaluminium compound used is too small, the catalytic activity may be inferior and the molecular weight distribution of the polyethylene produced may be narrow. If the amount of the alkylaluminium compound used is too large, the activity of the catalyst may drop sharply.

The reaction with the alkylaluminium compound may be carried out at -30 to 100 ° C, preferably at 0 to 30 ° C. The contact time is preferably sufficiently contacted for 0.5 to 24 hours from the time when the reaction is carried out.

The present invention also provides a catalyst prepared according to the process for producing the catalyst for polyethylene polymerization. In one embodiment, the catalyst may comprise a magnesium compound, a transition metal compound, and a compound of Formula 1:

[Chemical Formula 1]

In Formula 1,

R ₁ is selected from the group consisting of hydrogen, linear or branched alkyl having 1 to 20 carbon atoms, alkenyl having 2 to 20 carbon atoms, cycloalkyl having 3 to 20 carbon atoms, aryl having 6 to 20 carbon atoms Alkylsilyl having 1 to 20 carbon atoms, alkylsilyl having 7 to 20 carbon atoms, or alkyl having 2 to 20 carbon atoms containing a hetero atom.

In one embodiment of the present invention, the catalyst composition may further comprise an alkylaluminium compound represented by the following formula (3).

(3)

R _3n AlX _3-n

In Formula 3,

R ₃ is an alkyl group having 1 to 8 carbon atoms,

X is halogen,

n is from 0 to 3;

The present invention also provides a process for producing polyethylene comprising polymerizing or copolymerizing ethylene monomers in the presence of a catalyst prepared by the process.

The synthesis reaction may be carried out in a gas phase, a liquid phase, or a solution phase. When the synthesis reaction is carried out in a liquid phase, a hydrocarbon solvent can be used, and ethylene itself can be used as a solvent. The synthesis temperature may be from 0 to 200 캜, preferably from 50 to 150 캜. If the synthesis temperature is less than 0 占 폚, the activity of the catalyst is not good, and if it exceeds 200 占 폚, the stereoregularity becomes poor, which is not preferable. The synthesis pressure may be from 1 to 100 atm and preferably from 2 to 30 atm. When the synthesis pressure exceeds 100 atm, it is not preferable from the industrial and economical viewpoints. The synthesis reaction can be carried out by any of batch, semi-continuous and continuous processes.

The heat stabilizer, the light stabilizer, the flame retardant, the carbon black, the pigment, the antioxidant and the like which are conventionally added can be added to the polyethylene produced by using the solid catalyst according to the present invention. The polyethylene produced may be mixed with linear low density polyethylene (LLDPE), low density polyethylene (LDPE), high density polyethylene (HDPE), EP (ethylene / propylene) rubber and the like.

BRIEF DESCRIPTION OF THE DRAWINGS The above and other objects, features and advantages of the present invention will be more apparent from the following detailed description taken in conjunction with the accompanying drawings, in which: FIG. However, this is provided as an example of the invention, and the scope of the invention is not limited thereto in any sense.

Example

[Example 1: Preparation of catalyst and synthesis of polyethylene]

1) Preparation of magnesium compound solution

90 g of magnesium chloride, 450 ml of decane and 502 ml of ethylhexanol were charged into a 2 liter pressure glass reactor equipped with a stainless steel stirrer and an oil circulating heater under nitrogen atmosphere. Lt; / RTI > The temperature of the mixture was raised to 135 ° C. to completely dissolve the magnesium compound. When the mixture became a homogeneous solution, 9.5 ml of cyclopentylmethyl carbonate was aged for 1 hour, aged for 1 hour, and then cooled to 25 ° C. To prepare a magnesium compound solution.

2) Production of solid carrier and preparation of solid titanium catalyst

370 ml of titanium tetrachloride was added to 2900 ml of hexane as a solvent and aged for 30 minutes. Stirring was carried out at a rotation speed of 700 rpm so that hexane and titanium tetrachloride could be in a homogeneous solution state. 1500 ml of the magnesium compound solution prepared above was gradually added over 3 hours. The temperature of the reaction was maintained at -15 ° C. Upon completion of the addition, the reactor was aged for 1 hour and then the temperature of the reactor was raised from -15 ° C to 20 ° C at a rate of 0.3 ° C / min.

When the temperature of the reactor reached 20 占 폚, the reactor was aged for 30 minutes and then the temperature of the reactor was raised to 75 占 폚 at a rate of 1 占 폚 / min and aged at 74 占 폚 for 2 hours. After the reactor was cooled to 40 ° C, the stirring was stopped and the precipitate was removed. The supernatant was removed and washed 5 times with 2 liters of hexane at 40 ° C. The final slurry was dried under vacuum for 30 minutes to obtain a catalyst.

3) Synthesis of polyethylene

The 2 liter high-pressure reactor heated at 125 ° C was purged with nitrogen for 1 hour to allow the high pressure reactor to be in a nitrogen atmosphere. The reactor was cooled to 25 ° C under a nitrogen atmosphere and 1 liter of purified hexane was injected. 2 mmol triethylaluminum, 1 mg of the catalyst prepared above was added. After the addition, when the temperature of the reactor reaches 70 ° C. while stirring at 250 rpm, 2.2 bar is charged based on the hydrogen partial pressure and the temperature is raised to 75 ° C. When the temperature reached 75 캜, ethylene was injected and the polymerization reaction was carried out for 2 hours while keeping the total pressure of the high-pressure reactor at 7.1 bar. After completion of the reaction, the temperature of the reactor is cooled to room temperature, and the resulting polyethylene is filtered to remove the remaining monomer. The obtained polyethylene was dried for 2 hours in a vacuum oven at 60 DEG C, and the yield, apparent density and polymer particle size were measured.

Example 2

A catalyst was synthesized in the same manner as in Example 1 except that 3.8 ml of cyclopentylmethyl carbonate was added in the step of preparing the magnesium compound solution to prepare polyethylene.

Example 3

A catalyst was synthesized and polyethylene was prepared in the same manner as in Example 1, except that 18.9 ml of cyclopentylmethyl carbonate was added in the step of preparing the magnesium compound solution.

Example 4

A catalyst was synthesized and polyethylene was prepared in the same manner as in Example 1, except that 27.3 ml of cyclopentylmethyl carbonate was added in the step of preparing the magnesium compound solution.

Comparative Example 1

Except that 6.8 ml of ethyl benzoate was added instead of cyclopentylmethyl carbonate in the preparation of the magnesium compound solution to prepare polyethylene.

Comparative Example 2

Except that 34.2 ml of diisobutyl phthalate was added instead of cyclopentylmethyl carbonate in the step of preparing the magnesium compound solution, and polyethylene was synthesized in the same manner as in Example 1.

Comparative Example 3

Except that 21.6 ml of dibutyl ether was added instead of cyclopentylmethyl carbonate in the preparation of the magnesium compound solution, to prepare polyethylene.

Experimental Example 1

The particle shape of the product obtained in the above Examples and Comparative Examples was observed with an electron microscope (SEM: Scanning Electron Microscope), and the apparent density was measured. The particle size of the catalyst particles suspended in hexane was measured by a light transmission method using a laser particle analyzer (Mastersizer X, manufactured by Malvern Instruments) to obtain a cumulative distribution of the particle sizes, and the average particle size, particle size distribution The index was obtained as follows.

(One) Average particle size (D ₅₀ ): the particle size corresponding to the cumulative weight of 50%

(2) Particle size distribution index (P): P = (D ₉₀ -D ₁₀ ) / D ₅₀

(Where D ₉₀ is the particle size corresponding to the cumulative weight of 90% and D ₁₀ is the particle size corresponding to the cumulative weight of 10%),

Experimental Example 2: Analysis of molecular weight distribution (Mw / Mn) of polyethylene

The molecular weight distribution was measured by gel permeation chromatography according to the method according to DIN 55672 under the following conditions: solvent: 1,2,4-trichlorobenzene, flow rate: 1 ml / min, temperature: Calibration using.

division Catalyst particle size
(탆) Catalyst particle size distribution index Ti content
(wt%) activation
(Kg-PE / g-cat) Polymer average particle size
(탆) surface
density
(g / ml) MWD Example 1 5.4 0.99 3.4 13.6 121 0.30 5.8 Example 2 6.2 1.02 3.4 14.1 142 0.33 6.1 Example 3 6.6 1.05 3.5 12.9 168 0.29 6.2 Example 4 7.2 0.88 3.3 11.8 177 0.29 5.9 Comparative Example 1 6.9 0.72 3.8 16.7 198 0.26 6.5 Comparative Example 2 6.5 1.32 3.0 10.5 166 0.30 5.6 Comparative Example 3 8.9 1.10 3.5 15.2 183 0.28 4.3

According to the present invention, there is provided a polyethylene polymerization catalyst capable of producing chlorinated polyethylene excellent in mechanical properties by controlling not only a high activity and a bulk density in the polymerization reaction of polyethylene, but also a particle size and a distribution degree and a molecular weight distribution of the produced polyethylene do.

While the present invention has been particularly shown and described with reference to specific embodiments thereof, those skilled in the art will appreciate that such specific embodiments are merely preferred embodiments and that the scope of the present invention is not limited thereby. something to do. Accordingly, the actual scope of the present invention will be defined by the appended claims and their equivalents.

Claims (15)

(A) dissolving a magnesium compound in a solvent containing a first hydrocarbon solvent having 5 to 25 carbon atoms and an alcohol to prepare a magnesium compound solution;
(B) reacting the magnesium compound solution with a compound represented by the following formula (1); And
(C) reacting the product of step (B) with a transition metal compound in the presence of a second hydrocarbon solvent having 6 to 25 carbon atoms.
[Chemical Formula 1]

In Formula 1,
R ₁ is selected from the group consisting of hydrogen, linear or branched alkyl having 1 to 20 carbon atoms, alkenyl having 2 to 20 carbon atoms, cycloalkyl having 3 to 20 carbon atoms, aryl having 6 to 20 carbon atoms Alkylsilyl having 1 to 20 carbon atoms, alkylsilyl having 7 to 20 carbon atoms, or alkyl having 2 to 20 carbon atoms containing a hetero atom. The process according to claim 1, wherein the compound of formula (1) is at least one selected from the group consisting of cyclopentyl methyl carbonate, cyclopentyl ethyl carbonate, cyclo 2-methylpropyl carbonate and cyclopentyl 1,1- Gt; The method of producing a catalyst for polymerization of polyethylene according to claim 1, wherein the transition metal compound comprises a compound of the following formula (2):
(2)
MX _n (OR ₂ ) _4-n
In Formula 2,
M is selected from the group consisting of transition metal elements of groups IVB, VB and VIB of the periodic table,
X is halogen,
R ₂ is an alkyl group having 1 to 10 carbon atoms,
n is an oxidation number of the metal of 0 to 4; The method of claim 1, wherein the first hydrocarbon solvent and the second hydrocarbon solvent are each independently selected from the group consisting of hexane, heptane, octane, decane, dodecane, tetradecane, mineral oil, cyclic hexane, cyclic octane, Wherein the at least one compound is at least one compound selected from the group consisting of methyl cyclic hexane, benzene, toluene, xylene, ethylbenzene and cumene. The magnesium compound according to claim 1, wherein the magnesium compound is selected from the group consisting of magnesium halide, dialkoxymagnesium, alkyl magnesium halide having 1 to 20 carbon atoms, alkoxy magnesium halide having 1 to 20 carbon atoms, and aryloxy magnesium halide having 6 to 20 carbon atoms Lt; RTI ID = 0.0 > 1, < / RTI > The method of producing a polyethylene polymerization catalyst according to claim 1, wherein the molar ratio of the magnesium compound and the first hydrocarbon solvent in the step (A) is 1: 5 to 1:20. The method of producing a catalyst for polyethylene polymerization according to claim 1, wherein the molar ratio of the magnesium compound and the alcohol is 1: 0.5 to 1:10 in the step (A). The method of producing a catalyst for polyethylene polymerization according to claim 1, wherein the molar ratio of the magnesium compound to the compound of Formula 1 is 1: 0.01 to 1: 1. The method of producing a catalyst for polyethylene polymerization according to claim 1, wherein the molar ratio of the magnesium compound and the transition metal compound is 1: 0.01 to 1:10. The method of producing a catalyst for polymerization of polyethylene according to claim 1, wherein the step (A) is carried out at 60 to 150 ° C. The method of producing a catalyst for polymerization of polyethylene according to claim 1, wherein the step (B) is carried out at -10 to 150 ° C. 2. The method of producing a catalyst for polymerization of polyethylene according to claim 1, wherein the step (C) is carried out at -20 to 0 占 폚. The method of producing a catalyst for polyethylene polymerization according to claim 1, further comprising the step of (D) reacting with an alkylaluminium compound represented by the following formula (3):
(3)
R _3n AlX _3-n
In Formula 3,
R ₃ is an alkyl group having 1 to 8 carbon atoms,
X is halogen,
n is from 0 to 3; 14. The method of claim 13, wherein the alkylaluminium compound is selected from the group consisting of triethylaluminium, trimethylaluminium, triisopropylaluminium, trioctylaluminium, diethylaluminium chloride, diethylaluminium bromide, diethylaluminium iodide Wherein the at least one compound is at least one compound selected from the group consisting of diethylaluminium fluoride, ethylaluminium dichloride, dimethylaluminium chloride and methylaluminum dichloride. A process for the production of polyethylene, comprising polymerizing or copolymerizing ethylene monomers in the presence of a catalyst prepared by the process according to any one of claims 1 to 14.