KR102287924B1 - Method for producing catalyst for synthesis of high density polyethylene - Google Patents

Abstract

The present invention provides a method for preparing a catalyst for polymerization of high-density polyethylene, a catalyst for polymerization of high-density polyethylene, and a method for preparing polyethylene using the catalyst. The method for preparing the catalyst comprises the steps of: (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 dialkoxyphenyl; and (C) reacting the product of step (B) with the transition metal compound in the presence of a second hydrocarbon solvent having 6 to 25 carbon atoms. The catalyst of the present invention includes a magnesium compound, a transition metal compound and a dialkoxyphenyl. The catalyst has a constant shape and has a small particle size and a narrow particle size distribution. In addition, the ethylene polymer obtained after polymerization is characterized by high activity, a narrow molecular weight distribution, and low generation of fine powder.

Description

Method for producing a catalyst for high-density polyethylene polymerization {METHOD FOR PRODUCING CATALYST FOR SYNTHESIS OF HIGH DENSITY POLYETHYLENE}

The present invention relates to a method for preparing a catalyst for polymerization of high-density polyethylene having a narrow molecular weight distribution, and to the catalyst prepared thereby. More specifically, the present invention includes dialkoxyphenyl as an internal electron donor, has a small catalyst particle size, has a constant shape, shows high activity in polyethylene polymerization, and has a narrow molecular weight distribution to produce high-density polyethylene with less fine powder It relates to a method for preparing a catalyst for, and a catalyst prepared thereby.

A Ziegler-Natta type catalyst is used to polymerize olefins such as ethylene and propylene. The shape and size of the polymer polymerized using the Ziegler-Natta type catalyst is determined by the shape and performance of the catalyst used. Therefore, the particle size and distribution of the catalyst are very important in order to increase productivity, uniform the particle size of the polymer, and prepare a polymer advantageous for product molding. In addition, the physical properties of the polymer produced after polymerization are mostly determined by the structure constituting the catalyst.

The catalyst for high-density polyethylene polymerization is highly active, and the higher the apparent density of the polymer produced and the lower the fine powder formation, the better the catalyst. In addition, the polymer produced after polymerization may have a narrow or broad molecular weight distribution. The present invention relates to a catalyst for polymerization of high-density polyethylene having a narrow molecular weight distribution.

Polymers with many fine particles accumulate in the polymerization equipment in the olefin polymerization process, causing many problems. Specifically, small holes for the flow of the drying device used when drying the polymer obtained in the slurry process are highly likely to be clogged by fine particles and cause various problems, such as lowering the ability to transport the polymer product.

As a method for preparing such a catalyst, a recrystallization method is widely used until now. In addition, a catalyst preparation method using a precursor is also known. A catalyst using such a precursor is described in Korean Patent Publication No. 10-1716507. The catalyst is a catalyst composition including an internal electron donor (dialkoxybenzene) in a precursor made of a magnesium and titanium compound, and the use of the catalyst composition for polymerization of propylene is disclosed. A catalyst having such a precursor can produce a polymer having a narrow molecular weight distribution during polymerization of propylene, but has low catalytic activity.

In addition, in Patent Publication No. 10-2012-0051673, _{by synthesizing a catalyst from a spherical support made of MgCl 2} /EtOH and polymerizing ethylene by introducing an external electron donor (dialkoxybenzene) during polymerization, a polymer having a narrow molecular weight distribution is disclosed to obtain. However, the catalyst using the spherical carrier has very low activity during ethylene polymerization, and the cost of the catalyst is too high, making it difficult to apply commercially.

Accordingly, there is a need for a recrystallization catalyst capable of producing a polymer having a narrow molecular weight distribution, which exhibits high activity in polymerization of polyethylene, meets a high apparent density, a small amount of fine powder, and has a narrow molecular weight distribution.

Republic of Korea Patent No. 10-1716507 Republic of Korea Patent Publication No. 10-2012-0051673

The present invention provides a method for preparing a catalyst for high-density polyethylene polymerization, which can synthesize an ethylene polymer having a constant shape, a narrow particle size distribution and a small particle size, as well as a high apparent density and a narrow molecular weight distribution and low fine powder formation. will be.

In addition, the present invention is to provide a catalyst for polymerization of high-density polyethylene prepared by the above method.

The present invention to solve the above problems,

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

(B) reacting a compound of Formula 1 with the magnesium compound solution; and

(C) provides a method for preparing a catalyst for polymerization of high density polyethylene, comprising the step of reacting the product of step (B) and the transition metal compound in the presence of a second hydrocarbon solvent having 6 to 25 carbon atoms:

[Formula 1]

In Formula 1,

R ¹ and R ² are each independently linear C ₁ -C ₁₀ alkyl, branched C ₃ -C ₁₀ alkyl, or cyclic C ₃ -C ₁₀ alkyl,

R ³ is a methyl group, a nitro group or an aldehyde group.

In addition, the present invention provides a catalyst for polymerization of high-density polyethylene comprising a magnesium compound, a transition metal compound, and a compound of Formula 1.

In addition, the present invention provides a method for producing high-density polyethylene comprising the step of polymerizing or copolymerizing an ethylene-based monomer in the presence of the catalyst.

The high-density polyethylene synthesized using the catalyst according to the present invention has a particularly narrow molecular weight distribution and low fine powder formation. Therefore, such high-density polyethylene has a narrow molecular weight distribution, which is advantageous for molding injection products, and has a low fine powder content, providing excellent results on the product surface after film and blow molding.

Any numerical ranges recited herein include all values between the lower value and the higher value, in increments of one unit, provided that there is a difference of at least two units between any lower value and any higher value.

As used herein, the term “composition” includes not only a composition, but also a mixture of substances comprising decomposition products and reaction products formed from substances of the composition.

As used herein, the term “polymer” refers to a polymer compound prepared by polymerization of monomers of the same or different types. As used herein, the term “polymer” includes homopolymers and copolymers.

the present invention

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

(B) reacting an internal electron donor with the magnesium compound solution; and

(C) provides a method for preparing a catalyst for polymerization of high-density polyethylene, comprising the step of reacting the product of step (B) and the transition metal compound in the presence of a second hydrocarbon solvent having 6 to 25 carbon atoms.

In one embodiment of the present invention, the internal electron donor is a compound represented by the following formula (1):

[Formula 1]

In Formula 1,

R ¹ and R ² are each independently linear C ₁ -C ₁₀ alkyl, branched C ₃ -C ₁₀ alkyl, or cyclic C ₃ -C ₁₀ alkyl,

R ³ is a methyl group, a nitro group or an aldehyde group.

Specifically, in the internal electron donor, R ¹ and R ² of Formula 1 are the same as or different from each other and each independently a methyl group, an ethyl group, n-propyl group, n-butyl group, n-hexyl group or phenylethanone, It ^{may be a compound including a structure in which R 3} is a methyl group, a nitro group, or an aldehyde group.

More specifically, the internal electron donor is 2-(2-ethoxyphenoxy)-1-phenylethanone (2-(2-ethoxyphenoxy)-1-phenylethanone), 3,4-dimethoxytoluene (3,4 -dimethoxytoluene), 3,4-diethoxytoluene (3,4-diethoxytoluene), 1,2-dibutoxy-4-nitrobenzene (1,2-dibutoxy-4-nitrobenzene), 1,2-dihexyloxy -4-nitrobenzene (1,2-dihexyloxy-4-nitrobenzene), 4-nitro-1,2-dipropoxybenzene (4-nitro-1,2-dipropoxybenzene), 3-isopropoxy-4 -Methoxybenzaldehyde (3-isopropoxy-4-methoxybenzaldehyde), 3-ethoxy-4-propoxybenzaldehyde (3-ethoxy-4-propoxybenzaldehyde), 4-butoxy-3-ethoxybenzaldehyde (4-butoxy-3 -ethoxybenzaldehyde), 3-ethoxy-4-isobutoxybenzaldehyde (3-ethoxy-4-isobutoxybenzaldehyde), 3-ethoxy-4- (pentyloxy) benzaldehyde (3-ethoxy-4- (pentyloxy) benzaldehyde), 4 -Methoxy-3-propoxybenzaldehyde, 4-methoxy-3-[(methoxybenzyl)oxy]benzaldehyde ), 3-ethoxy-4-[(methoxybenzyl)oxy]benzaldehyde (3-ethoxy-4-[(methoxybenzyl)oxy]benzaldehyde), 4-cyclopentyloxy-3-methoxybenzaldehyde (4-cyclopentyloxy -3-methoxybenzaldehyde, 3-[(2,6-dichlorobenzyl)oxy]-4-methoxybenzaldehyde (3-[(2,6-dichlorobenzyl)oxy]-4-methoxybenzaldehyde, 4-[(2,6- Dichlorobenzyl)oxy]-3-methoxybenzaldehyde (4-[(2,6-dichlorobenzyl)oxy]-3-met oxybenzaldehyde, 4-[(3,4-dichlorobenzyl)oxy]-3-ethoxybenzaldehyde (4-[(3,4-dichlorobenzyl)oxy]-3-ethoxybenzaldehyde, 3-[(bromobenzyl)oxy]- 4-Methoxybenzaldehyde (3-[(bromobenzyl)oxy]-4-methoxybenzaldehyde), 3-ethoxy-4-([3-(trifluoromethyl)benzyl]oxy)benzaldehyde (3-ethoxy-4-( [3-(trifluoromethyl)benzyl]oxy)benzaldehyde) may include one or more compounds selected from the group consisting of.

In one embodiment of the present invention, the internal electron donor is used in an amount of 0.03 to 0.3 mol based on 1 mol of the magnesium compound. When out of the above range, the catalyst activity may be lowered by preventing the formation of transition metal particles to be supported on the prepared catalyst.

Specific examples of the magnesium compound include magnesium halide, dialkoxy magnesium, alkylmagnesium halide, alkoxymagnesium halide, or aryloxy magnesium halide. In one embodiment, the magnesium compound is one selected from the group consisting of a magnesium halide, a dialkoxy magnesium, an alkylmagnesium halide having 1 to 20 carbon atoms, an alkoxymagnesium halide having 1 to 20 carbon atoms, and an aryloxy magnesium halide having 6 to 20 carbon atoms. It may be more than one kind of compound.

Specifically, the magnesium halide compound is a compound that does not have reducing properties, and may include magnesium chloride, magnesium dichloride, magnesium fluoride, magnesium bromide, magnesium iodide, phenoxy magnesium chloride, isopropoxy magnesium chloride, butoxy magnesium chloride, and the like. Among them, it is preferable to use magnesium dichloride because it is structurally and coordinately stable with a transition metal compound, which is the main active metal, and exhibits high activity.

In the present invention, the alcohol may be used without limitation as long as it is an alcohol known to be used in the preparation of a Ziegler-Natta catalyst for polyethylene polymerization. Specifically, methanol, ethanol, n-propanol, isopropanol, n-butanol, isobutanol, n-pentanol, isopentanol, neopentanol, cyclopentanol, n-hexanol, n-heptanol, n-octanol , aliphatic or alicyclic alcohols such as decanol, dodecanol, 2-methylpentanol, 2-ethylbutanol, and 2-ethylhexanol; Aromatic alcohols such as cyclohexanol, methylcyclohexanol, and α-methylbenzyl alcohol may be used. Among them, it is preferable to use an aliphatic or alicyclic alcohol or an alcohol having 2 or more carbon atoms, and 2-ethylhexanol is used. more preferably.

In the present invention, alcohol serves to improve catalyst performance by dissolving the magnesium compound and forming appropriate pores by bonding with the magnesium compound in the catalyst. In one embodiment of the present invention, the alcohol is used in an amount of 3 to 4 mol with respect to 1 mol of the magnesium compound. If the amount of alcohol used is less than 3 mol with respect to 1 mol of the magnesium compound, the activity is low when the alcohol is added. On the other hand, if it exceeds 4 mol, the transition metal compound loading rate is lowered and the catalyst particle size is increased.

In the present invention, the first hydrocarbon solvent serves to facilitate dispersion of the magnesium compound. When the first hydrocarbon solvent is not used, the magnesium compound may be difficult to dissolve by forming a hard mass upon contact with alcohol.

Specific examples of the first hydrocarbon solvent include aliphatic or alicyclic hydrocarbons having 5 to 25 carbon atoms, and among them, aliphatic or alicyclic hydrocarbon solvents having 6 to 17 carbon atoms are most preferred. More specific examples include aliphatic hydrocarbons such as hexane, heptane, octane, decane, dodecane, tetradecane, mineral oil having 5 to 25 carbon atoms (eg, Cas No. 8042-47-5, etc.); 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.

When the amount of the first hydrocarbon solvent is too little or too much, it may be difficult to control the catalyst particle size, and it may be difficult to control the transition metal compound and the donor loading ratio. Accordingly, the first hydrocarbon solvent is suitably used in an amount of 2 to 4 mol per 1 mol of the magnesium compound. If the amount of the first hydrocarbon solvent used is less than 2 mol with respect to 1 mol of the magnesium compound, the magnesium compound is not well dispersed, and on the other hand, if it exceeds 4 mol, the catalyst particle size and the transition metal compound loading rate are lowered, making it difficult to control. can

In one embodiment of the present invention, specific examples of the second hydrocarbon solvent having 6 to 25 carbon atoms include aliphatic or alicyclic hydrocarbons having 5 to 25 carbon atoms, and among them, aliphatic or alicyclic hydrocarbons having 6 to 17 carbon atoms. Group hydrocarbon solvents are preferred. More specific examples include aliphatic hydrocarbons such as hexane, heptane, octane, decane, dodecane, tetradecane, mineral oil having 5 to 25 carbon atoms (eg, Cas No. 8042-47-5, etc.); 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. In one embodiment, the second hydrocarbon solvent is hexane.

In one embodiment of the preparation method of the present invention, dilution with the second hydrocarbon solvent is used to control the particle size of the catalyst produced. If the second hydrocarbon solvent is not added, the catalyst particle diameter may be produced as small as 1 μm or less, and if the second hydrocarbon solvent is added too much, the catalyst particle diameter may increase and catalyst performance may be deteriorated. The second hydrocarbon solvent used for the reaction is used in an amount of 4 to 25 mol or 6 to 10 mol based on 1 mol of the magnesium compound. When the amount of the second hydrocarbon solvent exceeds 25 mol, the catalyst particle size increases. In general, in the case of a recrystallization catalyst, the pore volume and the transition metal distribution acting as an active site vary according to the catalyst particle size, so that the activity and the apparent density of the polymer are changed. As a result, as the catalyst particle size increases, the activity decreases. In addition, when the second hydrocarbon solvent is not used or used in an amount of less than 4 mol, the catalyst particle diameter is small, making it difficult to produce, and there are too many fine particles after the polymer is formed, so it is not suitable for application to molded products.

In one embodiment according to the present invention, the transition metal compound may include a compound of Formula 2 below.

[Formula 2]

MX _n (OR ⁴ ) _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 ⁴ is an alkyl group having 1 to 10 carbon atoms,

n is 0 to 4.

In one embodiment of the present invention, examples of the transition metal compound include TiCl ₄ , TiBr ₄ , TiCl ₃ , Ti(OC ₂ H ₅ ) ₃ Cl, Ti(OC ₂ H ₅ ) ₃ Br, Ti(OC ₃ H _{7 )} ) ₂ Cl ₂ , Ti(OC ₆ H ₅ ) ₂ Cl ₂ , and Ti(OC ₂ H ₅ )Cl ₃ . Mixtures of such transition metal compounds may also be used.

The transition metal compound may be used in an amount of 3 to 8 mol based on 1 mol of the magnesium compound. When the amount of the transition metal compound is less than 3 mol with respect to 1 mol of the magnesium compound, the activity may be lowered due to a low loading rate of the transition metal compound, and when it exceeds 8 mol, the loading ratio of the transition metal compound increases more than necessary. This reduces the pores in the catalyst, thereby reducing the activity, and increasing the metal residue rate in the polymer, which can increase human harm and environmental pollution.

In one embodiment of the present invention, step (B) of the manufacturing method may be performed at 75 to 130 °C.

In one embodiment of the present invention, step (C) of the manufacturing method may be performed at -20 to 0 °C. In one embodiment, the temperature may be -15 to 0 °C. A transition metal compound may be added to the magnesium mixture maintained at the above temperature. That is, the transition metal compound is input at -20 to 0 °C, and the catalyst particle size varies depending on the input temperature. When the transition metal compound is added at a temperature above 0 °C, the catalyst particle size is small, the catalyst particle size distribution is widened, and the hardness of the catalyst is lowered, thereby lowering the apparent density and increasing the fine powder formation. On the other hand, if the transition metal compound is added at less than -20 °C, the catalyst particle size may be large and the catalyst particle size distribution may be narrowed.

In one embodiment of the present invention, the dropwise addition time of the transition metal compound is 1 to 4 hours is appropriate. If the input time of the transition metal compound is less than 1 hour, there is a disadvantage in that the temperature rises due to a vigorous reaction and the catalyst particle size distribution is widened. When the particle size distribution of the catalyst is widened, the particle size distribution of the polymer produced after polymerization is widened, resulting in lower apparent density, and poor productivity due to difficult operating conditions during product molding.

In one embodiment of the present invention, the addition of the transition metal compound is carried out for 1 to 4 hours under stirring at a stirring speed of 50 to 600 rpm. If the stirring speed is too slow, the catalyst particles generated after bonding with the transition metal compound may agglomerate and the particle size may increase. In addition, if the stirring speed is too fast, the particles may be broken, resulting in a wide particle size distribution, and particles having a particle diameter of less than 3 μm of the catalyst may be generated.

In one embodiment of the present invention, the introduction of the transition metal compound is made slowly, because it is possible to prevent temperature exotherm and catalyst agglomeration. In addition, in consideration of the temperature rise after the completion of the addition of the transition metal compound, it may be maintained at the same temperature for a certain period of time, as a non-limiting example, at the same temperature for 30 to 90 minutes, and then the temperature may be gradually increased. In general, it is appropriate to raise the temperature to 0.1 to 0.5 °C/min. If the temperature rises suddenly and rapidly, the catalyst may be broken or agglomerated and the shape of the catalyst may change. After that, the temperature is gradually increased again to reach 70 to 80 °C. At this time, only when the temperature is raised gradually, the catalyst can be prevented from breaking or agglomerated, and the rapid reaction according to the temperature rise can be controlled. After that, the material in the catalyst is maintained for 2 to 3 hours to allow stable binding and reaction (eg, maintaining the reaction at 70 to 80 °C).

According to one embodiment of the present invention, a catalyst having excellent catalyst shape, particle size, and polymerization activity is generated only when the transition metal compound is added to a homogeneous mixture containing magnesium. On the other hand, when a homogeneous mixture containing magnesium is added to the transition metal compound, a catalyst having poor catalyst shape and particle size and low activity is prepared.

In addition, the present invention provides a method for preparing a catalyst for polymerization of high density polyethylene comprising the step of (D) reacting with an alkyl aluminum compound represented by the following formula (3) in addition to the steps (A) to (C).

[Formula 3]

R ⁵ _n AlX _3-n

In Formula 3,

R ⁵ is an alkyl group having 1 to 8 carbon atoms,

X is halogen,

n is 1 to 3.

The alkyl aluminum compound can form an active site by reducing the transition metal compound as a co-catalyst, thereby increasing catalytic activity. In particular, when the transition metal compound is reacted first and then the alkyl aluminum compound is reacted, the transition metal active sites can be more evenly distributed, so that polyethylene having a higher catalytic activity and a wide molecular weight distribution and improved processability can be produced.

Examples of the alkyl aluminum compound include triethylaluminum, trimethylaluminum, triisopropylaluminum, trioctylaluminum, diethylaluminum chloride, diethylaluminum bromide, diethylaluminum iodide, and diethylaluminum. Ethylaluminum fluoride, ethylaluminum dichloride, dimethylaluminum chloride, methylaluminum dichloride, etc. may be used.

The method for producing polyethylene of the present invention does not use an additional external electron donor.

In addition, the present invention provides a catalyst for polymerization of high density polyethylene. In one embodiment, the catalyst may include a magnesium compound, a transition metal compound, and an internal electron donor.

In addition, according to another embodiment of the present invention, there may be provided a catalyst for polymerization of high density polyethylene comprising a magnesium compound, a transition metal compound, and a compound of Formula 1 below:

[Formula 1]

In Formula 1,

R ¹ and R ² are each independently linear C ₁ -C ₁₀ alkyl, branched C ₃ -C ₁₀ alkyl, or cyclic C ₃ -C ₁₀ alkyl,

R ³ is a methyl group, a nitro group or an aldehyde group.

Since the internal electron donor directly affects molecular weight distribution, catalyst particle size, activity and hydrogen reactivity, an appropriate content in the catalyst is required. In one embodiment, the catalyst may include 2.0 to 5.0% by weight of the internal electron donor based on the total weight of the catalyst. When the content is less than 2.0% by weight, a polymer having a wide molecular weight distribution is produced, and when it exceeds 5.0% by weight, the catalyst particle size increases, catalytic activity is low, and hydrogen reactivity is poor.

In one embodiment, the catalyst may include 9.0 to 25.0 wt% of magnesium. When the magnesium content is less than 9.0% by weight, the catalyst shape is not preferable because it is far from a spherical shape, and the support rate of the transition metal compound is relatively high, resulting in excessively high activity. When the activity is too high, the particle size of the resulting polymer increases, which has a disadvantage in that the apparent density is lowered. On the other hand, when the magnesium content is more than 25% by weight, the carrying rate of the transition metal compound may be lowered, and thus the activity may be lowered.

In addition, the catalyst may contain 3.0 to 7.0% by weight of the transition metal. When the transition metal in the catalyst is included in less than 3.0 wt%, the ethylene polymerization activity is lowered, and when it is included in more than 7.0 wt%, the polymer apparent density is lowered, resulting in lower productivity.

In one embodiment, the catalyst may include 10.0 to 16.0% by weight of an alcohol compound. When the alcohol compound in the catalyst is included in an amount of less than 10.0% by weight, the transition metal loading ratio in the catalyst is lowered, and when it is included in an amount of more than 16.0% by weight, the catalyst particle size increases and the hardness of the catalyst decreases.

In addition, the catalyst may include 1.0 to 10.0% by weight of the second hydrocarbon solvent. When the amount of the second hydrocarbon solvent in the catalyst is less than 1.0% by weight, the performance of the catalyst is lowered during long-term storage, and when it is included in excess of 10.0% by weight, it may be difficult to handle the catalyst.

The catalyst according to the present invention is a catalyst having a constant shape having an average particle diameter of 3 to 8 μm and a particle size distribution index of 0.5 to 1.5. In one embodiment, the average particle diameter of the catalyst is 4 to 6 μm or 4 to 5 μm. The catalyst particle size and shape are determined according to the catalyst preparation reaction conditions.

In one embodiment of the present invention, an average particle diameter of 3 to 8 μm and a particle size distribution index of 0.5 to 1.5 are obtained by slowly adding and contacting a transition metal compound dropwise to a mixture in which a magnesium compound, an internal electron donor, and an alcohol are diluted in a second hydrocarbon solvent. Eggplants can produce catalysts. However, when a mixture containing a magnesium compound is added dropwise to titanium, the catalyst particle size may increase, and a polymer having low activity after polymerization and low apparent density is produced.

The catalyst of one embodiment of the present invention may have an apparent shape with a small particle diameter and a constant shape while including an internal electron donor.

In addition, the present invention may provide a method for producing high-density polyethylene comprising polymerizing or copolymerizing an ethylene-based monomer in the presence of the catalyst for polymerization of high-density polyethylene.

In one embodiment of the present invention, the catalytically polymerized ethylene polymer exhibits a molecular weight distribution MwD (Mw/Mn) of 6 or less, such as 3 to 6, and a melt flow index (MFR) of 35 or less. In one embodiment, the melt flow ratio (MI21.6/MI2.16) of the ethylene polymer is 20 to 35. In addition, the ethylene polymer is characterized by high apparent density and low fines formation.

Example

Hereinafter, the action and effect of the invention will be described in more detail through specific examples of the invention. However, this is presented as an example of the invention and the scope of the invention is not limited in any sense by this.

Example 1: Preparation of catalyst and polyethylene

1) Catalyst preparation

In a 0.5 liter pressure resistant glass reactor equipped with a stirrer and an oil circulation heater, 3.0 g of magnesium dichloride, 16 ml of 2-ethylhexanol, and 15 ml of decane were added under a nitrogen atmosphere, and the mixture was stirred at 80° C. at 300 rpm. . In order to completely dissolve the magnesium dichloride, the temperature was raised to 130 °C, the reaction was maintained for 1 hour when it became a homogeneous solution, and 0.4 ml of 3,4-dimethoxytoluene was added. After the addition, it was maintained at the same temperature for 1 hour, lowered to room temperature, 64 ml of hexane was added, and the temperature was lowered after stirring for 30 minutes. When the temperature was maintained at -10 °C, 16 ml of titanium tetrachloride was slowly added while stirring at 600 rpm. When the input was completed, the temperature was raised to 70 °C and maintained at the same temperature for 1 to 5 hours, then lowered to 45 °C to stop stirring, and the resulting solid particles were precipitated. Thereafter, the supernatant was removed, washed 5 times with 2 liters of hexane and dried to obtain a catalyst.

2) Polyethylene production

A 2 liter stainless steel autoclave dried at 120° C. for 2 hours was purged with nitrogen to make the inside of the reactor a nitrogen atmosphere. While maintaining a nitrogen atmosphere, the temperature inside the reactor was lowered to 25° C., and 1 liter of purified hexane was injected. 2.0 mmol of triethylaluminum diluted in hexane was added, and 1 ml of a diluted solution obtained by diluting 1 g of the catalyst obtained above in 100 ml of decane was added. After the input, the temperature of the reactor was raised to 75 °C while stirring at 250 rpm. After that, 2.2 bar of H ₂ and 7 bar of ethylene were supplied to maintain the pressure. Polymerization usually lasted for 2 hours and ethylene was fed to keep the pressure constant. After completion of the reaction, the solvent was removed by filtration under reduced pressure, and the residual hexane solvent was dried in a vacuum oven at 80° C. for 6 hours to obtain a polymer.

Example 2: Preparation of catalyst and polyethylene

A catalyst and polyethylene were prepared in the same manner as in Example 1, except that 42 ml of hexane was added in Example 1.

Example 3: Preparation of catalyst and polyethylene

A catalyst and polyethylene were prepared in the same manner as in Example 1, except that 0.6 ml of 3,4-dimethoxytoluene was added in Example 1.

Example 4: Preparation of Catalyst and Polyethylene

A catalyst and polyethylene were prepared in the same manner as in Example 1, except that 0.7 ml of 3,4-diethoxytoluene was added instead of 3,4-dimethoxytoluene in Example 1.

Example 5: Preparation of catalyst and polyethylene

A catalyst and polyethylene were prepared in the same manner as in Example 1, except that 0.7 ml of 1,2-dibutoxy-4-nitrobenzene was added instead of 3,4-dimethoxytoluene in Example 1.

Example 6: Preparation of Catalyst and Polyethylene

A catalyst and polyethylene were prepared in the same manner as in Example 1, except that 20 ml of titanium tetrachloride was added in Example 1.

Example 7: Preparation of Catalyst and Polyethylene

A catalyst and polyethylene were prepared in the same manner as in Example 1, except that titanium tetrachloride was added at a temperature of 0° C. in Example 1.

Example 8: Preparation of Catalyst and Polyethylene

A catalyst and polyethylene were prepared in the same manner as in Example 1, except that 0.6 ml of 1,2-dihexyloxy-4-nitrobenzene was added instead of 3,4-dimethoxytoluene in Example 1.

Example 9: Preparation of Catalyst and Polyethylene

A catalyst and polyethylene were prepared in the same manner as in Example 1, except that 0.5 ml of 4-nitro-1,2-dipropoxybenzene was added instead of 3,4-dimethoxytoluene in Example 1.

Example 10: Preparation of Catalyst and Polyethylene

A catalyst and polyethylene were prepared in the same manner as in Example 1, except that 0.7 ml of 3-isopropoxy-4-methoxybenzaldehyde was added instead of 3,4-dimethoxytoluene in Example 1.

Comparative Example 1: Preparation of catalyst and polyethylene

A catalyst and polyethylene were prepared in the same manner as in Example 1, except that 0.4 ml of 1,3-dimethoxybenzene was added instead of 3,4-dimethoxytoluene in Example 1.

Comparative Example 2: Preparation of catalyst and polyethylene

A catalyst and polyethylene were prepared in the same manner as in Example 1, except that hexane was not added in Example 1.

Comparative Example 3: Preparation of catalyst and polyethylene

A catalyst and polyethylene were prepared in the same manner as in Example 1, except that 19 ml of hexane was added in Example 1.

Comparative Example 4: Preparation of catalyst and polyethylene

A catalyst and polyethylene were prepared in the same manner as in Example 1, except that the temperature was 6° C. when titanium tetrachloride was added in Example 1.

Comparative Example 5: Preparation of catalyst and polyethylene

A catalyst and polyethylene were prepared in the same manner as in Example 1, except that 0.7 ml of tetraethoxysilicate was added instead of 3,4-dimethoxytoluene in Example 1.

Comparative Example 6: Preparation of catalyst and polyethylene

A catalyst and polyethylene were prepared in the same manner as in Example 1, except that 3,4-dimethoxytoluene was not added during the preparation of the catalyst in Example 1 and was added as an external electron donor during the polymerization process.

Comparative Example 7: Preparation of catalyst and polyethylene

_{Titanium tetrachloride (TiCl 4} ) was put into a 0.5 liter pressure resistant glass reactor equipped with a stirrer and an oil circulation heater at 0° C. under a nitrogen atmosphere, and stirred at 300 rpm. Then, a spherical carrier (MgCl ₂ /EtOH) was added under stirring at the same temperature. Then, 0.5 ml of 3,4-dimethoxytoluene was added, and the temperature was raised to 140° C. within 2 hours and maintained for 1 hour. Stirring was then stopped and a solid product was allowed to settle. Thereafter, the supernatant was removed, washed 5 times with 2 liters of hexane and dried to obtain a catalyst. Polyethylene was prepared in the same manner as in Example 1 using the catalyst.

Comparative Example 8: Preparation of catalyst and polyethylene

6.0 g of Mg ₃ Ti(OC ₂ H ₅ ) ₈ Cl ₂ (precursor disclosed in Example 1 of US 6,825,146) precursor _{was contacted with 100 ml of TiCl 4} solution and 0.5 ml of 3,4-dimethoxytoluene. The mixture was heated to 100° C. and held at that temperature for 60 minutes, then filtered to remove the solvent. The filtration process was repeated 3 times, after which the solid was dried with a flow of _{N 2 to obtain a catalyst.} Polyethylene was prepared in the same manner as in Example 1 using the catalyst.

Experimental Example 1: Evaluation of catalyst particles

The shape of the catalyst particles prepared according to the above Examples and Comparative Examples was observed with an electron microscope (SEM: Scanning Electron Microscope).

In addition, the particle size of the catalyst particles suspended in hexane was measured with a laser particle analyzer (Mastersizer X; manufactured by Malvern Instruments) by a light transmission method. As a result, a cumulative distribution of particle sizes was obtained, and the average particle diameter and particle size distribution index of the particles were obtained from this as follows, and are listed in Table 1.

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

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

In the above, D ₉₀ is the particle size corresponding to 90% of the cumulative weight, and D ₁₀ is the particle size corresponding to 10% of the cumulative weight.

Experimental Example 2: Polyethylene molecular weight distribution (Mw / Mn) analysis

The molecular weight distribution was measured by gel permeation chromatography carried out according to a method according to DIN 55672 under the following conditions: solvent: 1,2,4-trichlorobenzene, flow rate: 1 ml/min, temperature: 140 °C, PE standard correction using.

Experimental Example 3: Polyethylene Melt Index Analysis

Melt index (MI) was measured at 190° C. according to ASTM D-1238 with the following loads: MI _2.16 : 2.16 kg, MI _21.6 : 21.6 kg. MI _21.6 /MI _2.16 is defined as the melt flow ratio (MFRR).

division average particle diameter
(μm) particle size distribution index activation
(kg-PE/g-Cat) Apparent density
(g/cm ³ ) Differentiation wt%
(<125 μm) MwD
(Mw/Mn) MFRR Example 1 4.1 0.8 30 0.31 0.2 4.0 24 Example 2 4.4 0.7 32 0.30 0.8 4.1 29 Example 3 4.8 0.8 30 0.33 0.6 4.7 30 Example 4 4.9 0.9 32 0.33 1.2 4.5 28 Example 5 4.5 1.1 35 0.31 1.5 4.5 27 Example 6 4.8 1.2 36 0.30 0.9 4.8 31 Example 7 4.6 1.2 34 0.32 0.9 4.1 28 Example 8 4.3 1.0 30 0.33 0.8 4.1 25 Example 9 4.5 0.8 31 0.30 1.0 4.5 26 Example 10 4.8 1.1 32 0.32 0.9 4.2 27 Comparative Example 1 2.9 1.9 12 0.22 1.0 7.6 39 Comparative Example 2 1.2 1.5 13 0.24 55 8.0 42 Comparative Example 3 1.8 1.8 11 0.24 39 6.8 36 Comparative Example 4 2.6 2.7 10 0.22 46 6.6 36 Comparative Example 5 2.8 1.7 13 0.28 18 7.7 42 Comparative Example 6 10 1.9 18 0.23 26 5.6 46 Comparative Example 7 45 1.9 5 0.27 28 6.8 37 Comparative Example 8 26 1.8 8 0.28 22 7.2 38

As shown in Table 1, it is confirmed that the catalyst according to the embodiment of the present invention is highly active, has an average particle diameter of 4 to 5 μm, and has a narrow particle size distribution. In addition, it was confirmed that the synthesized polymer can significantly reduce the amount of fine powder produced, thereby improving the physical properties and appearance properties of the final product, and can prevent malfunctions of process machinery and errors in the manufacturing process that may occur due to fine particles. became In addition, it can be seen that the polymer synthesized using the catalyst according to the embodiment of the present invention has a high apparent density and a narrow molecular weight distribution.

Claims (17)

(A) preparing a magnesium compound solution by dissolving the magnesium compound in a solvent containing a first hydrocarbon solvent having 5 to 25 carbon atoms and an alcohol;
(B) reacting a compound of Formula 1 with the magnesium compound solution; and
(C) a method for preparing a catalyst for polymerization of high density polyethylene, comprising the step of reacting the product of step (B) and the transition metal compound in the presence of a second hydrocarbon solvent having 6 to 25 carbon atoms,
The average particle diameter of the catalyst is 4 to 5 μm, and the catalytic activity is 30 to 36 kg-PE/g-Cat.
The apparent density of the polyethylene polymerized using the catalyst is 0.30 to 0.33 g/cm ³ Manufacturing method:
[Formula 1]

In Formula 1,
R ¹ and R ² are each independently linear C ₁ -C ₁₀ alkyl, branched C ₃ -C ₁₀ alkyl, or cyclic C ₃ -C ₁₀ alkyl,
R ³ is a methyl group, a nitro group or an aldehyde group. According to claim 1, wherein the compound of Formula 1 is 3,4-dimethoxytoluene (3,4-dimethoxytoluene), 3,4-diethoxytoluene (3,4-diethoxytoluene), 1,2-dibutoxy-4 -nitrobenzene (1,2-dibutoxy-4-nitrobenzene), 1,2-dihexyloxy-4-nitrobenzene (1,2-dihexyloxy-4-nitrobenzene), 4-nitro-1,2- Dipropoxybenzene (4-nitro-1,2-dipropoxybenzene), 3-isopropoxy-4-methoxybenzaldehyde (3-isopropoxy-4-methoxybenzaldehyde), 3-ethoxy-4-propoxybenzaldehyde (3- ethoxy-4-propoxybenzaldehyde), 4-butoxy-3-ethoxybenzaldehyde (4-butoxy-3-ethoxybenzaldehyde), 3-ethoxy-4-isobutoxybenzaldehyde (3-ethoxy-4-isobutoxybenzaldehyde), 3-E Toxy-4-(pentyloxy)benzaldehyde (3-ethoxy-4-(pentyloxy)benzaldehyde), 4-methoxy-3-propoxybenzaldehyde, 4-methoxy-3-[ (methoxybenzyl)oxy]benzaldehyde (4-methoxy-3-[(methoxybenzyl)oxy]benzaldehyde), 3-ethoxy-4-[(methoxybenzyl)oxy]benzaldehyde (3-ethoxy-4-[ (methoxybenzyl)oxy]benzaldehyde), 4-cyclopentyloxy-3-methoxybenzaldehyde, 3-[(2,6-dichlorobenzyl)oxy]-4-methoxybenzaldehyde (3- [(2,6-dichlorobenzyl)oxy]-4-methoxybenzaldehyde, 4-[(2,6-dichlorobenzyl)oxy]-3-methoxybenzaldehyde (4-[(2,6-dichlorobenzyl)oxy]-3- methoxybenzaldehyde, 4-[(3,4-dichlorobenzyl)oxy]-3-ethoxybenzaldehyde (4-[(3,4-di chlorobenzyl)oxy]-3-ethoxybenzaldehyde, 3-[(bromobenzyl)oxy]-4-methoxybenzaldehyde (3-[(bromobenzyl)oxy]-4-methoxybenzaldehyde), 3-ethoxy-4-([3 -(trifluoromethyl)benzyl]oxy)benzaldehyde (3-ethoxy-4-([3-(trifluoromethyl)benzyl]oxy)benzaldehyde) A high-density polyethylene polymerization catalyst comprising at least one selected from the group consisting of manufacturing method. The method of claim 1, wherein the transition metal compound comprises a compound of Formula 2 below:
[Formula 2]
MX _n (OR ⁴ ) _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 ⁴ is an alkyl group having 1 to 10 carbon atoms,
n is 0 to 4. According to claim 1, wherein the first hydrocarbon solvent and the second hydrocarbon solvent are each independently hexane, heptane, octane, decane, dodecane, tetradecane, mineral oil, cyclic hexane, cyclic octane, methyl cyclic pentane, A method for preparing a catalyst for polymerization of high density polyethylene, which 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 a magnesium halide, a dialkoxy magnesium, an alkylmagnesium halide having 1 to 20 carbon atoms, an alkoxymagnesium halide having 1 to 20 carbon atoms, and an aryloxy magnesium halide having 6 to 20 carbon atoms. A method for preparing a catalyst for polymerization of high-density polyethylene, which is at least one compound. According to claim 1, wherein in step (A), the input molar ratio of the magnesium compound and the first hydrocarbon solvent is 1:2 to 1:4, the method for preparing a catalyst for high-density polyethylene polymerization. The method according to claim 1, wherein in step (A), the input molar ratio of the magnesium compound and the alcohol is 1:3 to 1:4, the method for preparing a catalyst for high density polyethylene polymerization. The method of claim 1, wherein the input molar ratio of the magnesium compound and the compound of Formula 1 is 1:0.03 to 1:0.3, the method for preparing a catalyst for high density polyethylene polymerization. The method of claim 1 , wherein the input molar ratio of the magnesium compound and the transition metal compound is 1:3 to 1:8. The method of claim 1, wherein the input molar ratio of the magnesium compound and the second hydrocarbon solvent is 1:4 to 1:25. The method of claim 1, wherein step (C) is performed at -20 to 0°C. The method of claim 1, further comprising the step of (D) reacting with an alkyl aluminum compound represented by the following formula (3):
[Formula 3]
R ⁵ _n AlX _3-n
In Formula 3,
R ⁵ is an alkyl group having 1 to 8 carbon atoms,
X is halogen,
n is 1 to 3. 13. The method of claim 12, wherein the alkyl aluminum compound is triethylaluminum, trimethylaluminum, triisopropylaluminum, trioctylaluminum, diethylaluminum chloride, diethylaluminum bromide, diethylaluminum ioda A method for preparing a catalyst for polymerization of high-density polyethylene, which is at least one compound selected from the group consisting of id, diethylaluminum fluoride, ethylaluminum dichloride, dimethylaluminum chloride and methylaluminum dichloride. based on the total weight of catalyst
9.0 to 25.0 wt% of a magnesium compound,
3.0 to 7.0 wt% of a transition metal compound, and
As a catalyst for high-density polyethylene polymerization, comprising 2.0 to 5.0% by weight of the compound of Formula 1,
The average particle diameter of the catalyst is 4 to 5 μm, and the catalytic activity is 30 to 36 kg-PE/g-Cat.
Catalysts having an apparent density of 0.30 to 0.33 g/cm ³ of polyethylene polymerized using the catalyst:
[Formula 1]

In Formula 1,
R ¹ and R ² are each independently linear C ₁ -C ₁₀ alkyl, branched C ₃ -C ₁₀ alkyl, or cyclic C ₃ -C ₁₀ alkyl,
R ³ is a methyl group, a nitro group, or an aldehyde group. 15. The method of claim 14, wherein the compound of Formula 1 is 3,4-dimethoxytoluene (3,4-dimethoxytoluene), 3,4-diethoxytoluene (3,4-diethoxytoluene), 1,2-dibutoxy-4 -nitrobenzene (1,2-dibutoxy-4-nitrobenzene), 1,2-dihexyloxy-4-nitrobenzene (1,2-dihexyloxy-4-nitrobenzene), 4-nitro-1,2- Dipropoxybenzene (4-nitro-1,2-dipropoxybenzene), 3-isopropoxy-4-methoxybenzaldehyde (3-isopropoxy-4-methoxybenzaldehyde), 3-ethoxy-4-propoxybenzaldehyde (3- ethoxy-4-propoxybenzaldehyde), 4-butoxy-3-ethoxybenzaldehyde (4-butoxy-3-ethoxybenzaldehyde), 3-ethoxy-4-isobutoxybenzaldehyde (3-ethoxy-4-isobutoxybenzaldehyde), 3-E Toxy-4-(pentyloxy)benzaldehyde (3-ethoxy-4-(pentyloxy)benzaldehyde), 4-methoxy-3-propoxybenzaldehyde, 4-methoxy-3-[ (methoxybenzyl group)oxy]benzaldehyde (4-methoxy-3-[(methoxybenzyl)oxy]benzaldehyde), 3-ethoxy-4-[(methoxybenzyl group)oxy]benzaldehyde (3-ethoxy-4-[ (methoxybenzyl)oxy]benzaldehyde), 4-cyclopentyloxy-3-methoxybenzaldehyde, 3-[(2,6-dichlorobenzyl)oxy]-4-methoxybenzaldehyde (3- [(2,6-dichlorobenzyl)oxy]-4-methoxybenzaldehyde, 4-[(2,6-dichlorobenzyl)oxy]-3-methoxybenzaldehyde (4-[(2,6-dichlorobenzyl)oxy]-3- methoxybenzaldehyde, 4-[(3,4-dichlorobenzyl)oxy]-3-ethoxybenzaldehyde (4-[(3,4-d ichlorobenzyl)oxy]-3-ethoxybenzaldehyde, 3-[(bromobenzyl)oxy]-4-methoxybenzaldehyde (3-[(bromobenzyl)oxy]-4-methoxybenzaldehyde), 3-ethoxy-4-([3 -(trifluoromethyl)benzyl]oxy)benzaldehyde (3-ethoxy-4-([3-(trifluoromethyl)benzyl]oxy)benzaldehyde) High-density polyethylene polymerization catalyst comprising at least one selected from the group consisting of . 15. The method of claim 14, wherein the magnesium compound is selected from the group consisting of a magnesium halide, a dialkoxy magnesium, an alkylmagnesium halide having 1 to 20 carbon atoms, an alkoxymagnesium halide having 1 to 20 carbon atoms, and an aryloxy magnesium halide having 6 to 20 carbon atoms. A catalyst for polymerization of high density polyethylene, which is at least one compound. The catalyst for polymerization of high density polyethylene according to claim 14, wherein the transition metal compound comprises a compound of Formula 2 below:
[Formula 2]
MX _n (OR ⁴ ) _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 ⁴ is an alkyl group having 1 to 10 carbon atoms,
n is 0 to 4.