KR102518938B1 - Metallocene supported catalyst and method for preparing polypropylene using the same - Google Patents

Abstract

The present invention relates to a supported metallocene catalyst and a method for producing polypropylene using the same. By using the supported catalyst comprising a single metallocene compound of the present invention, polypropylene having a high bulk density value can be prepared with excellent activity.

Description

Supported metallocene catalyst and method for producing polypropylene using the same {METALLOCENE SUPPORTED CATALYST AND METHOD FOR PREPARING POLYPROPYLENE USING THE SAME}

The present invention relates to a supported metallocene catalyst and a method for producing polypropylene using the same. According to the present invention, polypropylene having a high bulk density value can be prepared with excellent activity by using a supported catalyst containing a single metallocene compound.

Olefin polymerization catalyst systems can be classified into Ziegler-Natta and metallocene catalyst systems, and these two highly active catalyst systems have been developed according to their respective characteristics. Ziegler-Natta catalysts have been widely applied in existing commercial processes since their invention in the 1950s.

Since it is a multi-site catalyst in which several active sites are mixed, it is characterized by a wide molecular weight distribution of the polymer, and there is a problem that there is a limit to securing desired physical properties because the composition distribution of the comonomer is not uniform.

On the other hand, the metallocene catalyst is composed of a combination of a main catalyst mainly composed of a transition metal compound and a cocatalyst composed of an organometallic compound mainly composed of aluminum. Such a catalyst is a single site catalyst as a homogeneous complex catalyst. A polymer with a narrow molecular weight distribution and a uniform comonomer composition distribution is obtained according to the characteristics of a single active point, and the tacticity of the polymer, copolymerization characteristics, molecular weight, It has properties that can change crystallinity, etc.

US Patent No. 5,032,562 describes a method for preparing a polymerization catalyst by supporting two different transition metal catalysts on one supported catalyst. This is a method of producing a bimodal distribution polymer by supporting a titanium (Ti)-based Ziegler-Natta catalyst that produces a high molecular weight and a zirconium (Zr)-based metallocene catalyst that produces a low molecular weight on one support. As a result, the supporting process is complicated, and the morphology of the polymer is deteriorated due to the cocatalyst.

US Patent No. 5,525,678 describes a method of using a catalyst system for olefin polymerization in which a high molecular weight polymer and a low molecular weight polymer can be simultaneously polymerized by simultaneously supporting a metallocene compound and a non-metallocene compound on a carrier. This has disadvantages in that the metallocene compound and the non-metallocene compound must be separately supported, and the carrier must be pretreated with various compounds for the loading reaction.

U.S. Patent No. 5,914,289 describes a method for controlling the molecular weight and molecular weight distribution of a polymer using a metallocene catalyst supported on each carrier, but the amount of solvent used and preparation time are required when preparing the supported catalyst. However, it was cumbersome to support each of the metallocene catalysts used on the carrier.

As described above, various attempts have been made to prepare a metallocene catalyst capable of producing polyolefin exhibiting excellent physical properties with high activity, but the extent is still insufficient.

The present invention is to provide a metallocene-supported catalyst capable of producing polypropylene having a high bulk density value with significantly improved activity.

In addition, the present invention is to provide a method for producing polypropylene using the supported metallocene catalyst.

According to one embodiment of the invention, a metallocene compound represented by Formula 1 below; and

A supported metallocene catalyst comprising a silica carrier having an average particle diameter of 20 μm to 30 μm and a water content of less than 1.0% is provided:

[Formula 1]

In Formula 1,

A is carbon, silicon, or germanium;

X is each independently a halogen or an alkyl group having 1 to 20 carbon atoms,

R ₁ to R ₅ are each independently an alkyl group having 1 to 20 carbon atoms.

In addition, according to another embodiment of the invention, in the presence of the above-described supported metallocene catalyst, there is provided a method for producing polypropylene, comprising the step of preparing polypropylene by polymerizing propylene.

The supported metallocene catalyst of the present invention can produce polypropylene having a high bulk density value with excellent activity.

In the present invention, terms such as first and second are used to describe various components, and the terms are used only for the purpose of distinguishing one component from another.

In addition, terms used in this specification are only used to describe exemplary embodiments, and are not intended to limit the present invention. Singular expressions include plural expressions unless the context clearly dictates otherwise. In this specification, terms such as "comprise", "comprise" or "having" are intended to indicate that there is an embodied feature, number, step, component, or combination thereof, but one or more other features or It should be understood that the presence or addition of numbers, steps, components, or combinations thereof is not precluded.

Also, in the present invention, when each layer or element is referred to as being formed “on” or “above” each layer or element, it means that each layer or element is directly formed on each layer or element, or other This means that layers or elements may be additionally formed between each layer or on the object or substrate.

Since the present invention can have various changes and various forms, specific embodiments will be exemplified and described in detail below. However, it should be understood that this is not intended to limit the present invention to the specific disclosed form, and includes all modifications, equivalents, and substitutes included in the spirit and scope of the present invention.

metallocene supported catalyst

According to one embodiment of the invention, a metallocene compound represented by Formula 1; And a silica carrier having an average particle diameter of 20 μm to 30 μm and a water content of less than 1.0%; a supported metallocene catalyst is provided, including:

[Formula 1]

In Formula 1,

A is carbon (C), silicon (Si), or germanium (Ge);

X is each independently a halogen or an alkyl group having 1 to 20 carbon atoms,

R ₁ to R ₅ are each independently an alkyl group having 1 to 20 carbon atoms.

As used herein, the term 'average particle diameter of silica' refers to the average particle diameter of silica secondary particles, that is, the average particle diameter of agglomerates of silica primary particles. It is different from the particle diameter of the silica primary particles measured in a state where the particles are not agglomerated.

In addition, the term 'moisture content' used herein may be understood as the amount of moisture remaining during silica production or mixed into silica during silica storage.

In the case of a metallocene-supported catalyst having a structure in which a conventional metallocene compound not containing an N-tether group is supported on a silica carrier, the bonding strength between the metallocene compound and the silica carrier is not good, so that the metallocene compound is uniformly There has been a problem in that the supported amount of the metallocene compound is small or the metallocene compound is not uniformly supported, so that the catalytic activity is lowered.

Therefore, the inventors of the present invention, when a metallocene compound having an N-tether group is used as a catalyst and supported on a silica carrier having an average particle diameter of a specific size and having a low moisture content, the bonding strength of the metallocene compound and silica The present invention was completed by confirming that the activity of the supported catalyst could be increased by increasing the supported amount of the metallocene compound.

Specifically, since the N-tether group in the metallocene compound has stronger nucleophilicity than other tether groups such as O-tether group, it can strongly bond with silica. Accordingly, compared to the metallocene compound having an O-tether group, the metallocene compound having an N-tether group can be supported in a uniform form while increasing the loading amount of silica. In addition, when the metallocene compound is supported on silica having a particle diameter of a specific size, better activity can be exhibited than when the metallocene compound having a different tether group is supported on silica having the above-described particle diameter in the same amount.

Accordingly, the metallocene-supported catalyst according to one embodiment does not have an average particle diameter in the above-described range of a silica-supported catalyst using a metallocene compound having no N-tether group and a metallocene compound having an N-tether group. It can exhibit significantly improved catalytic activity compared to a supported catalyst supported on a silica carrier without In addition, polypropylene prepared using the supported metallocene catalyst has a high bulk density (BD), so commercial productivity can be expected.

Hereinafter, the metallocene-supported catalyst of one embodiment will be described in more detail for each configuration.

A metallocene compound according to an embodiment is represented by Chemical Formula 1 above. The compound represented by Formula 1 not only has an N-tether group, but also the delocalization of electrons between the N-tether group and the phenylene linker can make the bond with the silica carrier stronger, and thus the activity of the supported catalyst can rise

In addition, due to this increase in catalytic activity, the supported metallocene catalyst according to one aspect of the present invention can exhibit high catalytic efficiency in the propylene polymerization reaction even without a separate cocatalyst.

Specifically, in Chemical Formula 1, A is silicon, X is independently halogen, and R ₁ to R ₅ may each independently be an alkyl group having 1 to 5 carbon atoms.

More specifically, in Formula 1, A is silicon, X is halogen, R ₁ to R ₅ are each independently methyl, ethyl, propyl, isopropyl, butyl, isobutyl, sec-butyl or tert-butyl can be

In this case, in Formula 1, R ₁ and R ₂ may be the same as each other, and R ₄ and R ₅ may be the same as each other.

For example, the metallocene compound represented by Chemical Formula 1 may be represented by:

The metallocene compound represented by Chemical Formula 1 may be prepared by preparing a ligand compound by connecting an indene derivative with a bridge compound, and then adding a metal precursor compound to perform metallation, but is not limited thereto. .

More specifically, for example, a lithium salt is prepared by reacting an indene derivative with an organolithium compound such as n-BuLi, a halogenated compound of a bridging compound is mixed, and the mixture is reacted to prepare a ligand compound. After mixing the ligand compound or its lithium salt and the metal precursor compound and reacting for about 12 hours to about 24 hours until the reaction is completed, the reaction product is filtered and dried under reduced pressure to obtain the metallocene compound represented by Formula 1. can be obtained A method for preparing the metallocene compound represented by Chemical Formula 1 will be described in detail in Examples to be described later.

On the other hand, in the metallocene-supported catalyst according to one embodiment, the carrier includes a silica carrier having an average particle diameter of 20 μm to 30 μm and a moisture content of less than 1.0%.

When the average particle diameter of the particles of the silica carrier is less than 20 μm, there may be insufficient space for sufficient support, so there may be no effect of increasing catalytic activity and bulk density, and when it exceeds 30 μm, the support space is very sufficient, It may be difficult to express the difference in bearing characteristics between the duggi and other tethers. The average particle diameter of these silica secondary particles can be measured using a particle measuring instrument, Capillary Hydrodynamic Fractionation (CHDF, manufactured by MATEC APPLIED SCIENCE, Model 1100).

In addition, when the moisture content of the silica carrier is 1.0% or more, the remaining moisture can lower the activity of the catalyst, so the lower the moisture content, the better. Accordingly, the lower limit of the moisture content of the silica carrier is not limited, but may be, for example, less than 1.0%, less than 0.95%, or less than 0.91%. The moisture content in the silica carrier can be measured using a thermogravimetric analyzer (Thermo-Gravimetric-Analyzer, manufactured by TA instrument).

Porous amorphous silica, for example porous silica gel, may be used as the silica carrier. That is, the silica carrier has a plurality of pores therein, and the above-described metallocene compound as well as a cocatalyst compound described later may be adsorbed into the internal pores to form a physical or chemical bond with the silica. Accordingly, the metallocene compound supported on the silica carrier may exhibit high catalytic activity for polypropylene synthesis.

In addition, such a silica carrier may be calcined to lower the moisture content and the content of silanol groups present on the surface of the silica. For example, the silica carrier may be calcined at a temperature of 500 °C to 800 °C for 10 to 15 hours. For example, the silica carrier may be calcined at 500 °C or higher, 550 °C or higher, or 600 °C or higher, and at 800 °C or lower, 750 °C or lower, or 700 °C or lower for the above-mentioned time.

In general, a large number of silanol groups (-Si-OH groups) exist on the surface of untreated silica. When the amount of these silanol groups is too large, side reactions with metallocene compounds and/or cocatalysts described later are present. can cause Therefore, it is preferable to induce a dehydration reaction in neighboring silanol groups through high-temperature firing, thereby changing some of the silanol groups on the silica surface to form siloxane groups (-Si-O-Si- groups). In addition, the silica carrier may be calcined in the above temperature range to lower the water content to less than 1%.

Specifically, when the silica is calcined at an excessively low temperature, the high moisture content on the surface of the silica carrier causes a reaction with the catalyst precursor, the metallocene compound and the cocatalyst, or the high moisture content lowers the catalyst activity and loading rate. Accordingly, the bulk density of the polymerized polypropylene may be low. In addition, when the silica is calcined at an excessively high temperature, most of the silanol groups on the surface of the silica carrier are present in the form of siloxane groups, and the reaction sites between the catalyst precursor and the cocatalyst may decrease. Therefore, by using the silica carrier calcined in the above-described temperature range, it is possible to manufacture polypropylene having a high bulk density according to the increase in catalyst activity and support rate.

More specifically, the amount of silanol groups, that is, hydroxyl groups (-OH), on the surface of the silica carrier calcined in the above-described temperature range is 0.1 to 10 mmol/g, more preferably 0.1 to 1 mmol/g, still more preferably is 0.1 to 0.5 mmol/g.

In addition, the silica carrier, specifically, the silica carrier calcined at the above-mentioned temperature may have a pore volume of 1.3 to 1.7 ml/g and a specific surface area of 270 to 320 m ² /g. When using a silica carrier having a pore volume and a specific surface area within the above ranges, the metallocene compound is effectively supported, and polypropylene having a high bulk density with high catalytic activity can be prepared.

At this time, the pore volume of the silica carrier can be measured by the absorption / desorption amount of nitrogen according to the partial pressure (0.11 <p / po <1) using an ASAP 2010 device from Micrometrics. In addition, the specific surface area of the silica carrier is a value calculated using the following BET (Brunauer-Emmett-Teller) Equation 1, and the value means the surface area per unit mass of the entire particle, and the porous particle It is a value that considers not only the pores but also the surface of the non-porous part. For example, it can be calculated from the amount of nitrogen gas adsorption under liquid nitrogen temperature (77K) using BELSORP-mino II from BEL Japan. :

[Equation 1]

S: specific surface area (m ² /g)

Xm: monolayer capacity

N: Avogadro's number (6.02×10 ²³ )

Am: apparent cross-sectional area of the adsorbed molecule

And, in the metallocene-supported catalyst according to an embodiment, the supported amount of the metallocene compound may be 0.05 to 0.09 mmol based on 1 g of the silica carrier. When the metallocene compound is supported on the silica carrier within the above range, high catalytic activity may be exhibited.

Meanwhile, in the metallocene-supported catalyst, one or more of the compounds represented by Formula 2, Formula 3, or Formula 4 may be additionally supported as a cocatalyst on the silica carrier.

[Formula 2]

-[Al(R ₆ )-O] _m -

In Formula 2,

R ₆ may be the same as or different from each other, and each independently halogen; hydrocarbons of 1 to 20 carbon atoms; or a halogen-substituted hydrocarbon having 1 to 20 carbon atoms;

m is an integer of 2 or greater;

[Formula 3]

J(R ₇ ) ₃

In Formula 3,

R ₇ may be the same as or different from each other, and each independently halogen; hydrocarbons of 1 to 20 carbon atoms; or a halogen-substituted hydrocarbon having 1 to 20 carbon atoms;

J is aluminum or boron;

[Formula 4]

[EH] ⁺ [ZA' ₄ ] ^- or [E] ⁺ [ZA' ₄ ] ^-

In Formula 4,

E is a neutral or cationic Lewis acid;

H is a hydrogen atom;

Z is a Group 13 element;

A' may be the same as or different from each other, and each independently represents an aryl group having 6 to 20 carbon atoms or an alkyl group having 1 to 20 carbon atoms in which one or more hydrogen atoms are unsubstituted or substituted with halogen, hydrocarbon having 1 to 20 carbon atoms, alkoxy or phenoxy. am.

Non-limiting examples of the cocatalyst represented by Formula 2 include methyl aluminoxane, ethyl aluminoxane, isobutyl aluminoxane, or tert-butyl aluminoxane, and a more preferred compound is methyl aluminoxane.

Examples of the compound represented by Formula 3 include trimethyl aluminum, triethyl aluminum, triisobutyl aluminum, tripropyl aluminum, tributyl aluminum, dimethylchloro aluminum, triisopropyl aluminum, tri- s -butyl aluminum, tricyclopentyl aluminum , tripentyl aluminum, triisopentyl aluminum, trihexyl aluminum, trioctyl aluminum, ethyl dimethyl aluminum, methyl diethyl aluminum, triphenyl aluminum, tri-p-tolyl aluminum, dimethyl aluminum methoxide, dimethyl aluminum ethoxide, trimethyl Boron, triethylboron, triisobutylboron, tripropylboron, tributylboron, etc. are included, and a more preferable compound is selected from trimethylaluminum, triethylaluminum, and triisobutylaluminum.

Examples of the compound represented by Formula 4 include triethylammonium tetraphenylboron, tributylammonium tetraphenylboron, trimethylammonium tetraphenylboron, tripropylammonium tetraphenylboron, trimethylammonium tetra( p -tolyl) Boron, trimethylammonium tetra( o,p -dimethylphenyl) boron, tributylammonium tetra( p -trifluoromethylphenyl) boron, trimethylammonium tetra( p -trifluoromethylphenyl)boron, tributylammonium tetra Kispentafluorophenylboron, N,N -diethylanilinium tetraphenylboron, N,N -dimethylaniliniumtetrakispentafluorophenylboron, diethylammonium tetrakispentafluorophenylboron, triphenyl Phosphonium tetraphenylboron, trimethylphosphonium tetraphenylboron, triethylammonium tetraphenyl aluminum, tributylammonium tetraphenyl aluminum, trimethylammonium tetraphenyl aluminum, tripropylammonium tetraphenyl aluminum, trimethylammonium tetra ( p -Tolyl) aluminum, tripropylammonium tetra( p -tolyl) aluminum, triethylammonium tetra( o,p -dimethylphenyl)aluminum, tributylammonium tetra( p -trifluoromethylphenyl)aluminum, trimethylammonium Tetra( p -trifluoromethylphenyl)aluminum, tributylammonium tetrakispentafluorophenylaluminum, N,N -diethylanilinium tetraphenylaluminum, N,N -diethylanilinium tetrakispentafluoro Phenyl aluminum, diethylammonium tetrakispentatetraphenyl aluminum, triphenylphosphonium tetraphenyl aluminum, trimethylphosphonium tetraphenyl aluminum, tripropylammonium tetra( p -tolyl) boron, triethylammonium tetra( o,p -Dimethylphenyl) boron, tributylammonium tetra( p -trifluoromethylphenyl)boron, triphenylcarboniumtetra( p -trifluoromethylphenyl)boron, triphenylcarboniumtetrakispentafluorophenylboron, etc. there is

As such a cocatalyst, aluminoxane can be preferably used, and methyl aluminoxane (MAO), which is an alkyl aluminoxane, can be used more preferably. In addition, the cocatalyst may be used in an appropriate amount so that the activation of the metallocene compound, which is a catalyst precursor, can sufficiently proceed.

In addition, the molar ratio of the metallocene compound to the cocatalyst compound may be 1:10 to 1:130, 1:50 to 1:130, or 1:100 to 1:130. When the cocatalyst is supported on the silica carrier in the above range, the activity of the transition metal in the metallocene compound is increased, and thus the activity of the metallocene supported catalyst may be improved.

The supported metallocene catalyst may further include additives and adjuvants commonly used in the art to which the present invention pertains, in addition to the above components.

On the other hand, the metallocene-supported catalyst according to an embodiment includes the steps of supporting a cocatalyst compound on the above-described silica carrier; and supporting the above-described metallocene compound on a silica carrier supported with the cocatalyst compound.

In this case, the metallocene compound may be used in an amount of about 0.01 to about 100 parts by weight and the cocatalyst in an amount of about 1 to about 1,000 parts by weight, based on 100 parts by weight of the silica carrier. Preferably, the metallocene compound may be used in an amount of about 0.1 to about 50 parts by weight and the cocatalyst in an amount of about 10 to about 500 parts by weight, based on 100 parts by weight of the silica carrier, most preferably 100 parts by weight of the silica carrier. , the metallocene compound may be included in about 0.5 to about 20 parts by weight and the cocatalyst in about 40 to about 150 parts by weight.

In addition, the mass ratio of all transition metals to the carrier included in the metallocene compound may be 1:10 to 1:1,000. When the carrier and the metallocene compound are included in the above mass ratio, an optimal shape can be exhibited. In addition, the mass ratio of the cocatalyst compound to the carrier may be 1:1 to 1:100. When the cocatalyst and the metallocene compound are included in the above mass ratio, activity and polymer microstructure can be optimized.

In addition, a hydrocarbon solvent such as pentane, hexane, heptane, or the like, or an aromatic solvent such as benzene or toluene may be used as a reaction solvent during the preparation of the supported metallocene catalyst.

Manufacture of polypropylene

On the other hand, according to another embodiment of the invention, in the presence of the supported metallocene catalyst, it provides a method for producing polypropylene, comprising the step of preparing polypropylene by polymerizing propylene.

As described above, the metallocene-supported catalyst has increased catalytic activity by supporting the metallocene compound of Formula 1 including an N-tether substituent and an indene structure ligand at the same time on a silica carrier having a specific particle size. A polypropylene having a bulk density can be provided.

In the method for producing polypropylene according to an embodiment of the present invention. The supported catalyst including the metallocene compound of Chemical Formula 1 has improved catalytic activity than conventional Ziegler-Natta catalysts or metallocene catalysts, and the supporting conditions of the metallocene compound, that is, reaction temperature, reaction time, type of silica , Even if the supported amount of the metallocene compound is changed, polypropylene can be produced with improved activity.

Here, the polymerization of propylene may be performed by reacting for about 1 to about 24 hours at a temperature of about 25 to about 500 °C and a pressure of about 1 to about 100 kgf/cm ² . At this time, the polymerization reaction temperature is preferably about 25 to about 200 ℃, more preferably about 50 to about 100 ℃. In addition, the polymerization reaction pressure is preferably about 1 to about 70 kgf/cm ² , and more preferably about 5 to about 50 kgf/cm ² . The polymerization reaction time is preferably about 1 to about 5 hours.

The method for producing polypropylene of the present invention may be performed by contacting propylene with a catalyst including the metallocene compound represented by Chemical Formula 1.

Also, according to an embodiment of the present invention, the polymerization of propylene may be carried out under hydrogen gas.

At this time, the hydrogen gas activates the inactive site of the metallocene catalyst and causes a chain transfer reaction to control the molecular weight. The metallocene compound of the present invention has excellent hydrogen reactivity, and therefore, polypropylene having a desired level of molecular weight and melt index can be effectively obtained by controlling the amount of hydrogen gas used during the polymerization process.

The hydrogen gas may be introduced in an amount of about 30 to about 2,000 ppm, or about 50 to about 1,500 ppm, or about 50 to about 500 ppm, based on the weight of propylene. By adjusting the amount of hydrogen gas used, it is possible to control the molecular weight distribution and melt index (MI) of the polypropylene produced while exhibiting sufficient catalytic activity within a desired range, and thus polypropylene having appropriate physical properties depending on the use. can be manufactured. More specifically, the metallocene catalyst of the present invention has very good hydrogen reactivity, so that the chain transfer reaction is activated as the amount of hydrogen gas is increased, thereby obtaining polypropylene having a reduced molecular weight and a high melt index. can

The polypropylene production method may be performed by a solution polymerization process, a slurry process, or a gas phase process using one continuous slurry polymerization reactor, a loop slurry reactor, a gas phase reactor, or a solution reactor.

In the polypropylene production method according to the present invention, the catalyst is an aliphatic hydrocarbon solvent having 5 to 12 carbon atoms suitable for polymerization of olefinic monomers, such as pentane, hexane, heptane, nonane, decane, and isomers thereof It can be injected by dissolving or diluting in aromatic hydrocarbon solvents such as toluene and benzene, hydrocarbon solvents substituted with chlorine atoms such as dichloromethane and chlorobenzene. It is preferable to use the solvent used by removing a small amount of water or air that acts as a catalyst poison by treating a small amount of alkylaluminum.

The method for producing polypropylene may further include steps commonly employed in the technical field to which the present invention pertains, in addition to the steps described above.

Meanwhile, according to another embodiment of the present invention, polypropylene obtained by the above-described manufacturing method is provided.

As described above, according to the present invention, by using a catalyst containing the novel metallocene compound, it is possible to obtain polypropylene having an increased bulk density compared to the case of using a conventional metallocene compound.

Also, the above Polypropylene has a low processing temperature and excellent transparency and fluidity, so it can be used for packaging containers, films, sheets, injection molded products, textile products, etc. that require these properties.

According to an embodiment of the present invention, when the propylene polymerization process is performed using the catalyst containing the metallocene compound, the weight average molecular weight (Mw) of the polypropylene produced is the amount of hydrogen introduced during the polymerization process It may vary depending on, but may be from about 50,000 to about 1,000,000 g / mol, or from about 80,000 to about 500,000 g / mol, preferably from about 100,000 to about 300,000 g / mol. This weight average molecular weight (Mw) can be measured by gel chromatography (GPC) using PS Standard using an Agilent 1200 series.

In addition, the polypropylene prepared by the metallocene-supported catalyst described above has a bulk density of 0.40 g / cm ³ to 0.60 g/cm ³ . At this time, the bulk density is the density calculated including the volume of gas or liquid that occupies the space between the compounds in a certain volume, and is distinguished from the net density calculated by the density of the compound alone excluding the volume of the space. . In particular, the bulk density is usefully used when the compound has a particle form and it is not easy to accurately measure the true density. This bulk density can be measured by measuring the weight of the polypropylene filled in a container having a certain volume and then dividing the measured weight by the container volume value.

Specifically, the prepared polypropylene is 0.40 g/cm ³ or more, 0.41 g/cm ³ or more, 0.43 g/cm ³ or more, or 0.44 g/cm ³ or more, or 0.60 g/cm ³ or less, 0.58 g/cm ³ Or less, 0.55 g/cm ³ or less, or 0.50 g/cm ³ or less may have a bulk density value. If the bulk density of the polypropylene is too low, productivity decline and generation of static electricity due to the generation of fine powder may be a problem, and if the bulk density is too high, a production load increase and line transfer clogging may be a problem. Therefore, by using the metallocene-supported catalyst according to one embodiment, polypropylene having a bulk density value in the above-described range may be prepared to improve productivity.

In addition, the prepared polypropylene, due to the above characteristics, when measured with a load of 2.16 kg at 230 ℃ according to ASTM D1238, from about 1 to about 10 g / 10 min, preferably from about 5 to about 9 g / 10 min melt index (MI).

Hereinafter, the action and effect of the invention will be described in more detail through specific examples of the invention. However, these embodiments are only presented as examples of the invention, and the scope of the invention is not determined thereby.

< manufacturing example >

manufacturing example One: metallocene Preparation of compound 1

Step 1-1: 4-( dichloro(methyl)silyl )- N,N - dimethylaniline synthesis

4-Bromo-N,N-dimethylaniline (5.00 g, 25 mmol) and Mg (1.22 g, 50.2 mmol) were added to THF (25 mL) and stirred at 70 °C for 4 hours. After dissolving MeSiCl ₃ (7.47 g, 50.0 mmol) in THF (75 mL) in another flask, the above mixture was slowly added dropwise at 0 °C for 1 hour. After stirring the mixture at room temperature overnight, sat. NaHCO ₃ was added. After removing moisture with anhydrous MgSO ₄ and concentrating the resulting solution under reduced pressure, 4-(dichloro(methyl)silyl)-N,N-dimethylaniline (4.80 g, 82%) was obtained as a white solid.

¹ H NMR (500 MHz, CDCl ₃ , 7.24 ppm): 0.99 (3H, s), 3.01 (6H, s), 6.75 (2H,d), 7.57 (2H, d)

Steps 1-2: 4-( bis(4-(4-(tert-butyl) phenyl)-2-methyl-1H- inden Synthesis of -1-yl)(methyl)silyl)-N,N-dimethylaniline

4-(4-(tert-butyl)phenyl)-2-methyl-1H-indene (10.3 g, 39.3 mmol) and CuCN (176 mg, 1.97 mmol) were mixed with toluene (90 mL) and THF ( 12 mL). This solution was cooled to -30 °C and n-BuLi (2.5 M in hexane, 16.5 mL) was slowly added. After stirring at this temperature for about 10 minutes, the temperature was raised to room temperature, followed by stirring for 2 hours. To this solution, 4-(dichloro(methyl)silyl)-N,N-dimethylaniline (4.80 g, 20.5 mmol) prepared in step 1-1 was added to Toluene (30 mL) and stirred overnight at room temperature. After the reaction was completed, MTBE and water were added, and the organic layer was separated. The obtained organic layer was dried with anhydrous MgSO ₄ , concentrated, and then 4-(bis(4-(4-(tert-butyl)phenyl)-2-methyl-1H-inden-1-yl)(methyl)silyl)-N ,N-dimethylaniline (13.8 g, 100%) was obtained as a white solid.

¹ H NMR (500 MHz, CDCl ₃ , 7.24 ppm): 0.00 - 0.07 (3H, m), 1.49 - 1.52 (18H, m), 2.46 - 2.49 (6H, m), 3.00 (3H, s), 3.02 ( 3H, s), 4.23 - 4.39 (2H, m), 6.50 - 7.52 (20H, m)

Steps 1-3: [4-( bis(4-(4-(tert-butyl) phenyl)-2-methyl-1H- inden -1-yl)(methyl)silyl)-N,N-dimethylaniline] Zirconium dichloride synthesis

4-(bis(4-(4-(tert-butyl)phenyl)-2-methyl-1H-inden-1-yl)(methyl)silyl)-N,N-dimethylaniline(prepared in step 1-2 above) 6.74 g, 9.83 mmol) was put in a 50 mL Schlenk flask under argon (Ar) and dissolved by injecting diethyl ether (8.2 mL). After lowering the temperature to -78 °C and adding n-BuLi (2.5 M in hexane, 8.1 mL), the mixture was stirred at room temperature for 2 hours. ZrCl ₄ (2.29 g, 9.83 mmol) in Tol / diethyl ether (24.6 / 8.2 mL) slurry was slowly added to the Ligand solution at -78 ° C, and the mixture was heated to room temperature and stirred overnight. The solvent was distilled under reduced pressure, dissolved in CH ₂ Cl ₂ , and filtered to remove LiCl. After concentrating the filtrate, saturating the crude with CH ₂ Cl ₂ and adding hexane twice the volume, recrystallization was performed at -20 ° C for 15 hours. Afterwards, when a yellow solid is formed, it is filtered, washed twice with hexane, and then the title compound [4-(bis(4-(4-(tert-butyl)phenyl)-2-methyl-1H-inden-1-yl)( methyl)silyl)-N,N-dimethylaniline] to obtain zirconium dichloride (225 mg, 30%, r/m > 20/1).

^1H NMR (500 MHz, CDCl ₃ , 7.24 ppm): 1.30 - 1.40 (21H, m), 2.00 (3H, s), 2.33 (3H, s), 3.10 (6H, s), 6.85 - 7.94 (18H, m)

manufacturing example 2: metallocene Preparation of Compound A

Step 2-1: (6-(tert-butoxy)hexyl)bis(4-(4-(tert-butyl) Synthesis of phenyl)-2-methyl-1H-inden-1-yl)(methyl)silane

4-(4-(tert-butyl)phenyl)-2-methyl-1H-indene (10.3 g, 39.3 mmol) and CuCN (176 mg, 1.97 mmol) were mixed with toluene (90 mL) and THF (12 mL) under argon. dissolved in This solution was cooled to -30 °C and n-BuLi (2.5 M in hexane, 16.5 mL) was slowly added. After stirring at this temperature for about 10 minutes, the temperature was raised to room temperature, followed by stirring for 2 hours. To this solution, (6-(tert-butoxy)hexyl)dichloro(methyl)silane (5.56g, 20.5mmol) obtained above was added to Toluene (30mL) and stirred overnight at room temperature. After the reaction was completed, methyl tert-butyl ether (MTBE) and water were added, and the organic layer was separated. The obtained organic layer was dried with anhydrous MgSO ₄ , concentrated, and then (6-(tert-butoxy)hexyl)bis(4-(4-(tert-butyl)phenyl)-2-methyl-1H-inden-1-yl) (methyl)silane (14.8 g, 100%) was obtained as a pale yellow oil.

¹ H NMR (500 MHz, CDCl ₃ , 7.24 ppm): -0.10 - 0.91 (3H, m), 1.25 - 1.40 (27H, m), 1.92 - 2.38 (6H, m), 4.11 - 4.52 (4H, m), 6.44 - 7.91 (20H, m)

Step 2-2: [ (6-(tert-butoxy)hexyl)bis(4-(4-(tert-butyl) Synthesis of phenyl)-2-methyl-1H-inden-1-yl)(methyl)silane] Zirconium dichloride

(6-(tert-butoxy)hexyl)bis(4-(4-(tert-butyl)phenyl)-2-methyl-1H-inden-1-yl)(methyl)silane(prepared in step 2-1 above) 1.0g, 1.37mmol) was put into a 50mL Schlenk flask under argon (Ar) and dissolved by injecting diethyl ether (10mL). After lowering the temperature to -78°C, adding n-BuLi (2.5 M in hexane, 1.1mL), the mixture was stirred at room temperature for 2 hours. The solvent was distilled under vacuum and ZrCl ₄ (THF) ₂ (517mg, 1.37mmol) was added in a glove box, and the temperature was lowered to -78°C. After adding toluene (10 mL) to the mixture, the temperature was raised to room temperature and the mixture was stirred overnight. The solvent was distilled off under reduced pressure and washed with hexane to obtain a yellow solid. Dissolve this solid in toluene, filter the syringe, distill the filtrate under reduced pressure, and wash the solid with hexane to obtain yellow [(6-(tert-butoxy)hexyl)bis(4-(4-(tert-butyl) phenyl)-2-methyl-1H-inden-1-yl)(methyl)silane] Zirconium dichloride (225 mg, 18%, r/m > 10/1) was obtained.

¹ H NMR (500 MHz, CDCl ₃ , 7.24 ppm): 1.33 - 1.34 (21H, m), 1.37 (9H, s), 1.96 (3H, s), 2.33 (3H, s), 4.59 (2H, s), 6.86 (1H, t), 7.02 (1H, s), 7.06 (1H, s), 7.17 (2H, m), 7.33 (1H, d), 7.41 - 7.47 (5H, m), 7.55 - 7.62 (6H, m), 7.73 (1H, s), 8.06 (2H, d)

manufacturing example 3: Silica carrier manufacturing

Silica 1 (trade name 952x, manufactured by Grace) was classified into silica having an average particle size of 30 μm, 24.1 μm, 28.3 μm, and 19.1 μm through sieving to prepare silica 1a, silica 1b, silica 1c, and silica 1d. In addition, silica 2 (trade name SYLOPOL 2408, manufactured by Grace) and silica 3 (trade name P-10, manufactured by Fuji) having different average particle diameters from silica 1 were additionally prepared. The silica thus prepared was calcined using a small glass calcining device under nitrogen purge under the calcining temperature and time conditions shown in Table 1 below, respectively, to prepare a silica carrier.

The average particle diameter, pore volume, specific surface area and water content of the silica carrier prepared above were measured by the following methods, respectively, and the results are shown in Table 1 below.

(1) Average particle diameter: measured using a particle measuring device CHDF Model 1100 (manufactured by MATEC APPLIED SCIENCE).

(2) Pore volume: Measured using AUTOSORB iQ series (manufactured by Quantachrome) in accordance with ASTM D4641.

(3) Specific surface area: According to the above-mentioned BET (Brunauer-Emmett-Teller) Equation 1, it was measured by nitrogen gas adsorption amount under liquid nitrogen temperature (77K) using BELSORP-mino II (manufactured by BEL Japan). .

(4) Moisture content: Mass change was measured using a thermogravimetric analyzer (equipment name: TGA 550, manufactured by TA instrument) under conditions of heating from room temperature to 950 ° C at a rate of 30 ° C / min.

silica carrier firing temperature
(℃) firing time
(hr) average particle diameter
(μm) pore volume
(ml/g) specific surface area
(m ² /g) water content
(%) Silica 1a-250 250 12 30 1.63 310 2.6 Silica 1a-650 650 12 30 1.63 310 0.7 Silica 1b-250 250 12 24.1 1.32 299 2.9 Silica 1b-650 650 12 24.1 1.32 299 0.9 Silica 1c-250 250 12 28.3 1.58 302 3.1 Silica 1c-650 650 12 28.3 1.58 302 0.6 Silica 2-250 250 12 34 1.54 317 3.3 Silica 2-650 650 12 34 1.54 317 0.9 Silica 3-250 250 12 40.9 1.41 314 2.8 Silica 3-650 650 12 40.9 1.41 314 0.6 Silica 1d-250 250 12 19.1 1.69 283 3.1 Silica 1d-650 650 12 19.1 1.69 283 0.8

< Example : metallocene Preparation of Supported Catalyst>

Example One

A supported catalyst was prepared by supporting the metallocene compound 1 obtained in Preparation Example 1 after supporting methylaluminoxane on silica in the following manner.

First, the silica carrier 1a-650 (3 g) prepared in Preparation Example 3 was placed in a 250 mL Schlenk flask under argon, and methylaluminoxane (MAO, 27 mmol) was slowly injected at room temperature to 90 ° C. Stir for 18 hours. After completion of the reaction, the mixture was cooled to room temperature, allowed to stand for 15 minutes, and then the solvent in the upper layer was removed. After adding toluene (25mL), stirring for 3 minutes and leaving it for 10 minutes, the solvent in the upper layer was removed. After dissolving the metallocene compound (210 μmol) obtained in Preparation Example 1 in toluene (20mL), it was added to the flask using a cannula and washed with toluene (5mL). After stirring at 50° C. for 5 hours, cooling to room temperature and leaving it for 15 minutes, the solvent in the upper layer was removed. Toluene (25mL) was added, stirred for 3 minutes, allowed to stand for 10 minutes, and then the solvent in the upper layer was removed twice. In the same manner, hexane (25 mL) was added, stirred for 1 minute, left for 20 minutes, and then the solvent in the upper layer was removed and dried overnight. Additionally, vacuum drying was performed at 45° C. for 4 hours to prepare a supported metallocene catalyst.

Example 2 and 3

A supported metallocene catalyst was prepared in the same manner as in Example 1, except that silica carriers 1b-650 and 1c-650 were used instead of the silica carrier 1a-650 used in Example 1.

comparative example 1 to 15

A supported metallocene catalyst was prepared in the same manner as in Example 1, except that the metallocene compounds and silica carriers listed in Table 2 were used instead of the metallocene compound and silica carrier of Example 1, respectively. .

< Experimental example >

Manufacture of polypropylene

A 2L stainless reactor was vacuum-dried at 65° C. and then cooled, 3.0 mmol of triethylaluminum was added at room temperature, hydrogen was added at an amount of 337 ppm compared to propylene, and 770 g of propylene was sequentially added.

After stirring for 10 minutes, 0.030 g of each supported metallocene catalyst prepared in Examples and Comparative Examples was dissolved in 20 mL of TMA-prescribed hexane and introduced into the reactor under nitrogen pressure. Thereafter, the temperature of the reactor was gradually raised to 70° C., and polymerization was performed for 1 hour under conditions of 337 ppm hydrogen input and 35 kg/cm ² pressure to prepare polypropylene. After completion of the reaction, unreacted propylene was vented.

Measurement of physical properties of polypropylene

The bulk density and melt index of the polypropylene prepared using the metallocene-supported catalyst prepared in the above Examples and Comparative Examples, and the catalytic activity in the manufacturing process were measured by the following methods, respectively, and the results are shown in the table below. 2.

(1) Catalyst activity: calculated as the ratio of the weight of the polymer produced (kg PP) per catalyst content (mmol and g of catalyst) used per unit time (h).

(2) Bulk density: A cup dug with a volume of 1 cm ³ was placed on a scale and set to 0. After putting the resulting polymer in a 50 ml beaker, mixing it evenly, pouring it into a cup having a volume of 1 cm ³ , sweeping the cup once with a ruler to flatten the polypropylene, and then measuring the weight. The bulk density was measured by the measured weight.

(3) Melt index (MFR, 2.16 kg): Measured under a load of 2.16 kg at 230° C. according to ASTM D1238, and expressed as the weight (g) of the polymer melted for 10 minutes.

silica
carrier (catalyst)
metallocene
compound Catalytic amount ^*1
(μmol) Cocatalyst amount ^*1
(mmol) catalytic activity
(kg PP/g Cat.hr) bulk density
(g/cm ³ ) melt index
(g/10min) Example 1 silica
1a-650 compound 1 70 9 12.1 0.47 5.1 Example 2 Silica 1b-650 compound 1 70 9 12.5 0.44 7 Example 3 Silica 1c-650 compound 1 70 9 11.9 0.47 8.8 Comparative Example 1 Silica 1a-250 compound 1 70 9 10.9 0.39 3.4 Comparative Example 2 Silica 1b-250 compound 1 70 9 10.2 0.39 5.1 Comparative Example 3 Silica 1c-250 compound 1 70 9 10.1 0.38 4.9 Comparative Example 4 Silica 1a-250 compound A 70 9 9.1 0.38 9 Comparative Example 5 Silica 1a-650 compound A 70 9 10.2 0.37 8.1 Comparative Example 6 Silica 2-250 compound 1 70 9 7 0.37 10 Comparative Example 7 Silica 2-650 compound 1 70 9 9.9 0.38 7 Comparative Example 8 Silica 2-250 compound A 70 9 8.9 0.38 12 Comparative Example 9 Silica 2-650 compound A 70 9 10.1 0.39 14 Comparative Example 10 Silica 3-250 compound 1 70 9 8.1 0.34 17 Comparative Example 11 Silica 3-650 compound 1 70 9 10.5 0.32 20 Comparative Example 12 Silica 3-250 compound A 70 9 8.7 0.33 9.3 Comparative Example 13 Silica 3-650 compound A 70 9 10.9 0.34 8.1 Comparative Example 14 Silica 1d-650 compound 1 70 9 10.1 0.32 10.5 Comparative Example 15 Silica 1d-250 compound 1 70 9 9.9 0.31 12.1

*1) The amounts of catalysts and cocatalysts in Table 1 are based on 1 g of silica carrier.

Referring to Table 2, in the case of polymerizing propylene using the supported metallocene catalyst according to Examples, compared to the case of polymerizing propylene using the supported metallocene catalyst according to Comparative Example. It can be seen that it is possible to produce polypropylene having significantly improved catalytic activity and simultaneously increased bulk density.

Claims (11)

A metallocene compound represented by Formula 1 below; and
A supported metallocene catalyst comprising a silica carrier having an average particle diameter of 20 μm to 30 μm and a water content of less than 1.0%:
[Formula 1]

In Formula 1,
A is carbon, silicon, or germanium;
X is each independently a halogen or an alkyl group having 1 to 20 carbon atoms,
R ₁ to R ₅ are each independently an alkyl group having 1 to 20 carbon atoms.
According to claim 1,
In Formula 1,
A is silicon;
X is a halogen;
R ₁ to R ₅ are each independently methyl, ethyl, propyl, isopropyl, butyl, isobutyl, sec-butyl or tert-butyl, a supported metallocene catalyst.
According to claim 1,
The metallocene compound represented by Formula 1 is a supported metallocene catalyst represented by:

.
According to claim 1,
The silica carrier is calcined at a temperature of 500 ℃ to 800 ℃, the supported metallocene catalyst.
According to claim 1,
The silica carrier has a BET specific surface area of 270 to 320 m 2 / g, a metallocene supported catalyst.
According to claim 1,
The supported amount of the metallocene compound is 0.05 to 0.09 mmol based on 1 g of the silica carrier, the supported metallocene catalyst.
According to claim 1,
A supported metallocene catalyst further comprising at least one cocatalyst compound among the compounds represented by Formula 2, Formula 3, or Formula 4:
[Formula 2]
-[Al(R ₆ )-O] _m -
In Formula 2,
R ₆ may be the same as or different from each other, and each independently halogen; hydrocarbons of 1 to 20 carbon atoms; or a halogen-substituted hydrocarbon having 1 to 20 carbon atoms;
m is an integer of 2 or greater;
[Formula 3]
J(R ₇ ) ₃
In Formula 3,
R ₇ may be the same as or different from each other, and each independently halogen; hydrocarbons of 1 to 20 carbon atoms; or a halogen-substituted hydrocarbon having 1 to 20 carbon atoms;
J is aluminum or boron;
[Formula 4]
[EH] ⁺ [ZA' ₄ ] ^- or [E] ⁺ [ZA' ₄ ] ^-
In Formula 4,
E is a neutral or cationic Lewis acid;
H is a hydrogen atom;
Z is a Group 13 element;
A' may be the same as or different from each other, and each independently represents an aryl group having 6 to 20 carbon atoms or an alkyl group having 1 to 20 carbon atoms in which one or more hydrogen atoms are unsubstituted or substituted with halogen, hydrocarbon having 1 to 20 carbon atoms, alkoxy or phenoxy. am.
According to claim 7,
The molar ratio of the metallocene compound to the cocatalyst compound is 1:10 to 1:130, the supported metallocene catalyst.
A method for producing polypropylene, comprising the step of preparing polypropylene by polymerizing propylene in the presence of the supported metallocene catalyst of any one of claims 1 to 8.
According to claim 9,
The polymerization of the propylene is carried out by reacting for 1 to 24 hours at a temperature of 25 to 500 ° C. and a pressure of 1 to 100 kgf / cm ^{2 A} method for producing polypropylene.
According to claim 9,
The prepared polypropylene has a bulk density of 0.40 g/cm ³ to 0.60 g/cm ³ .