KR101723488B1 - Method for preparing polypropylene and polypropylene prepared therefrom - Google Patents

Abstract

The present invention relates to a process for producing polypropylene and polypropylene obtained therefrom. More particularly, the present invention relates to a process for producing a polypropylene using a mixed metallocene catalyst containing a novel metallocene compound having excellent polymerization activity and a polypropylene obtained therefrom.
According to the present invention, by polymerizing propylene using two kinds of metallocene compounds, it is possible to easily control physical properties of polypropylene, and to obtain polypropylene excellent in mechanical properties, workability, fluidity, and crystallinity.

Description

[0001] The present invention relates to a process for preparing polypropylene and a polypropylene obtained therefrom,

The present invention relates to a process for producing polypropylene and polypropylene obtained therefrom. More particularly, the present invention relates to a process for producing polypropylene using a mixed metallocene catalyst having excellent polymerization activity and a polypropylene obtained therefrom.

Olefin polymerization catalyst systems can be classified into Ziegler-Natta and metallocene catalyst systems, both of which have been developed for their respective characteristics. Ziegler-Natta catalysts have been widely applied to commercial processes since the invention of the 50's. However, since the Ziegler-Natta catalyst is a multi-site catalyst having a plurality of active sites, the molecular weight distribution of the polymer is broad, The composition distribution is not uniform and there is a limit in securing desired physical properties.

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, which is an organometallic compound mainly composed of aluminum. Such a catalyst is a single site catalyst as a homogeneous complex catalyst, . The polymer has a narrow molecular weight distribution according to the single active site property and a homogeneous composition distribution of the comonomer is obtained. According to the modification of the ligand structure and the polymerization conditions of the catalyst, the stereoregularity of the polymer, Crystallinity and so on.

Among the metallocene catalysts, the ansa-metallocene compound is an organometallic compound containing two ligands connected to each other by a bridge group, in which the rotation of the ligand is prevented by the bridge group, The activity and structure of the metal center are determined.

These anisometallocene compounds are used as catalysts in the production of olefinic homopolymers or copolymers. In particular, it is known that an anisometallocene compound containing a cyclopentadienyl-fluorenyl ligand can produce a high molecular weight polyethylene, thereby controlling the microstructure of the polypropylene have. It is also known that an anhydride-metallocene compound containing an indenyl ligand can produce a polyolefin having excellent activity and improved stereoregularity.

Korean Patent Laid-Open No. 10-2013-0125311 discloses a novel anthra-metallocene compound capable of providing various selectivity and activity to polyolefin copolymers.

On the other hand, since the polypropylene resin produced by the metallocene catalyst generally has a high melting point, it is disadvantageous to use a high temperature for adhesion between the sealing layers when it is applied to a heat sealing film. There is still a need for a polypropylene having a properly controlled xylene solubles content and a method for producing such a polypropylene exhibiting a high sealing strength.

In order to solve the above problems, the present invention provides a process for producing polypropylene which polymerizes propylene in the presence of a mixed metallocene catalyst containing a metallocene compound having a novel structure.

The present invention also provides a polypropylene obtained by the above production method.

The present invention relates to a process for the production of a poly (meth) acrylate polymer comprising the step of polymerizing propylene in the presence of a mixed metallocene catalyst comprising a first metallocene compound represented by the following formula (1) and a second metallocene compound represented by the following formula A process for producing propylene is provided.

[Chemical Formula 1]

In Formula 1,

X is the same or different halogen,

R1 is C6-C20 aryl substituted with alkyl having 1 to 20 carbon atoms,

R2, R3 and R4 are the same or different and each independently represents hydrogen, halogen, alkyl of 1 to 20 carbon atoms, alkenyl of 2 to 20 carbon atoms, alkylsilyl of 1 to 20 carbon atoms, silylalkyl of 1 to 20 carbon atoms, Alkoxysilyl of 1 to 20 carbon atoms, ether of 1 to 20 carbon atoms, silyl ether of 1 to 20 carbon atoms, alkoxy of 1 to 20 carbon atoms, aryl of 6 to 20 carbon atoms, alkylaryl of 7 to 20 carbon atoms, Lt; / RTI >

A is carbon, silicon or germanium,

R5 is alkyl having 1 to 20 carbon atoms substituted with alkoxy having 1 to 20 carbon atoms,

R6 is hydrogen, alkyl of 1 to 20 carbon atoms or alkenyl of 2 to 20 carbon atoms.

(2)

_{(CpR 7) n (Cp'R 8} ) MQ 3 -n

In Formula 2,

M is a Group 4 transition metal;

Cp and Cp 'are the same or different and are each independently selected from the group consisting of cyclopentadienyl, indenyl, 4,5,6,7-tetrahydro-1-indenyl, and fluorenyl radical , Which may be substituted with hydrocarbons having 1 to 20 carbon atoms;

R 7 and R 8 are the same or different from each other and each independently represents hydrogen, alkyl having 1 to 20 carbon atoms, alkoxy having 1 to 10 carbon atoms, aryl having 6 to 20 carbon atoms, aryloxy having 6 to 10 carbon atoms, Alkenyl having 7 to 40 carbon atoms, arylalkyl having 7 to 40 carbon atoms, arylalkenyl having 8 to 40 carbon atoms, or alkynyl having 2 to 10 carbon atoms;

Q is selected from the group consisting of halogen, alkyl of 1 to 20 carbon atoms, alkenyl of 2 to 10 carbon atoms, alkylaryl of 7 to 40 carbon atoms, arylalkyl of 7 to 40 carbon atoms, aryl of 6 to 20 carbon atoms, A substituted or unsubstituted amino group, an alkylalkoxy group having 2 to 20 carbon atoms, or an arylalkoxy group having 7 to 40 carbon atoms,

n is 1 or 0;

The present invention also provides polypropylene obtained by the above-mentioned production method.

According to the method for producing polypropylene according to the present invention, the propylene can be easily polymerized by polymerizing propylene using a mixed metallocene catalyst containing a novel metallocene compound having excellent polymerization activity, A polypropylene having improved processability and excellent physical properties can be obtained.

The polypropylene obtained by the process for producing polypropylene according to the present invention shows high transparency and is excellent in mechanical properties, processability, fluidity and crystallinity and can be used for various purposes. In particular, Can be usefully used.

Hereinafter, a method for producing polypropylene according to a specific embodiment of the invention and polypropylene obtained by the method will be described in more detail. It is to be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the invention as defined by the appended claims.

In addition, throughout this specification, "comprising" or "containing ", unless specifically stated, refers to including any and all components (or components) Can not be interpreted as excluding.

According to an aspect of the present invention, there is provided a process for polymerizing propylene in the presence of a mixed metallocene catalyst comprising a first metallocene compound represented by the following formula (1) and a second metallocene compound represented by the following formula The method comprising the steps of:

[Chemical Formula 1]

In Formula 1,

X is the same or different halogen,

R1 is C6-C20 aryl substituted with alkyl having 1 to 20 carbon atoms,

R2, R3 and R4 are the same or different and each independently represents hydrogen, halogen, alkyl of 1 to 20 carbon atoms, alkenyl of 2 to 20 carbon atoms, alkylsilyl of 1 to 20 carbon atoms, silylalkyl of 1 to 20 carbon atoms, Alkoxysilyl of 1 to 20 carbon atoms, ether of 1 to 20 carbon atoms, silyl ether of 1 to 20 carbon atoms, alkoxy of 1 to 20 carbon atoms, aryl of 6 to 20 carbon atoms, alkylaryl of 7 to 20 carbon atoms, Lt; / RTI >

A is carbon, silicon or germanium,

R5 is alkyl having 1 to 20 carbon atoms substituted with alkoxy having 1 to 20 carbon atoms,

R6 is hydrogen, alkyl of 1 to 20 carbon atoms or alkenyl of 2 to 20 carbon atoms.

(2)

_{(CpR 7) n (Cp'R 8} ) MQ 3-n

In Formula 2,

M is a Group 4 transition metal;

Cp and Cp 'are the same or different from each other, and each independently selected from the group consisting of cyclopentadienyl, indenyl, 4,5,6,7-tetrahydro-1-indenyl, and fluorenyl radical , Which may be substituted with hydrocarbons having 1 to 20 carbon atoms;

R 7 and R 8 are the same or different from each other and each independently represents hydrogen, alkyl having 1 to 20 carbon atoms, alkoxy having 1 to 10 carbon atoms, aryl having 6 to 20 carbon atoms, aryloxy having 6 to 10 carbon atoms, Alkenyl having 7 to 40 carbon atoms, arylalkyl having 7 to 40 carbon atoms, arylalkenyl having 8 to 40 carbon atoms, or alkynyl having 2 to 10 carbon atoms;

Q is selected from the group consisting of halogen, alkyl of 1 to 20 carbon atoms, alkenyl of 2 to 10 carbon atoms, alkylaryl of 7 to 40 carbon atoms, arylalkyl of 7 to 40 carbon atoms, aryl of 6 to 20 carbon atoms, A substituted or unsubstituted amino group, an alkylalkoxy group having 2 to 20 carbon atoms, or an arylalkoxy group having 7 to 40 carbon atoms,

n is 1 or 0;

The first metallocene compound of Formula 1 has an anis-metallocene structure and includes two indenyl groups as a ligand. In particular, a bridge group connecting the ligand is substituted with a functional group capable of acting as a Lewis base as an oxygen-donor, thereby maximizing the activity as a catalyst. In addition, since a bulky group such as an aryl (R1) having 6 to 20 carbon atoms and substituted with an alkyl having 1 to 20 carbon atoms is substituted for the indenyl group, steric hindrance is imparted to inhibit formation of the meso form . Accordingly, when the first metallocene compound represented by the general formula (1) is supported on its own or on a carrier and used as a catalyst in the production of polyolefins, a polyolefin having desired physical properties can be more easily produced. In addition, by including hafnium (Hf) as a metal atom, it is possible to increase the activity of the catalyst and to polymerize polyolefins having a higher molecular weight, and it is possible to mix the catalyst with other metallocene catalysts, I have.

Preferably, R1 is phenyl substituted with tert-butyl. More preferably, R1 is 4-tert-butyl phenyl.

Also preferably, R 2, R 3 and R 4 are hydrogen.

Also preferably, A is silicon (Si).

Also preferably, R5 is 6-tert-butoxy hexyl and R6 is methyl.

Representative examples of the first metallocene compound represented by Formula 1 are as follows, but the present invention is not limited thereto.

The first metallocene compound of formula (1) can be synthesized by the production method shown in the following reaction formula (1).

[Reaction Scheme 1]

In the above Reaction Scheme 1, X, R 1 to R 6, and A are as defined in Formula 1 above.

In step 1 of Scheme 1, it is preferable to use alkyllithium (for example, n-butyllithium), and the reaction temperature is -200 to 0 占 폚, more preferably -150 to 0 占 폚 . As the solvent, toluene, THF and the like can be used. At this time, the organic layer may be separated from the product, and then the separated organic layer may be vacuum dried and excess reactant may be removed.

In the above Step 2, it is preferable to use alkyllithium (for example, n-butyllithium), and the reaction temperature is -200 to 0 占 폚, more preferably -150 to 0 占 폚. As the solvent, ether, hexane and the like can be used.

The second metallocene compound represented by Formula 2 may be, for example, a compound represented by the following structural formula, but is not limited thereto.

Meanwhile, in the polymerization reaction of propylene of the present invention, the physical properties of polypropylene produced by controlling the content ratio of the first and second metallocene compounds can be controlled.

In particular, the hybrid metallocene catalyst may contain the second metallocene compound in a relatively low amount. More specifically, the first and second metallocene compounds may be included in a molar ratio of from about 10: 1 to about 1: 1, preferably from about 6: 1 to about 3: 1. When the first and second metallocene compounds are contained at such a molar ratio, polypropylene exhibiting a narrow molecular weight distribution and improved processability can be provided. In particular, due to the combination of the first metallocene compound contributing to the production of the high molecular weight polymer and the second metallocene compound contributing to the preparation of the low molecular weight polymer, the xylene solubles content Can be adjusted to a desired range, so that the processability is improved and polypropylene for a heat seal film having a high sealing strength can be produced.

According to the production method of the present invention, the hybrid metallocene catalyst may be prepared by reacting a first metallocene compound represented by the formula (1) and a second metallocene compound represented by the formula (2) , Mixed supported metallocene catalyst.

In this case, the mixed supported metallocene catalyst may be prepared by 1) supporting a promoter on a support, 2) supporting the first metallocene compound represented by the formula 1 on the support, and 3) 2 as a second metallocene compound, but the present invention is not limited thereto.

The carrier may be any of those generally used in the technical field to which the present invention belongs, so that it is not particularly limited, but preferably at least one carrier selected from the group consisting of silica, silica-alumina and silica-magnesia may be used. On the other hand, when supported on a carrier such as silica, since the silica carrier and the functional group of the metallocene compound are chemically bonded and supported, there is almost no catalyst liberated from the carrier surface in the olefin polymerization process, There is an advantage that no fouling occurs in which the wall surface of the reactor or the polymer particles are entangled with each other during the production.

In addition, the polypropylene produced in the presence of the hybrid supported metallocene catalyst containing such a carrier is excellent in particle shape and bulk density of the polymer, and can be suitably used for conventional slurry polymerization, bulk polymerization and gas phase polymerization processes .

Therefore, it is preferable to use a carrier which is dried at a high temperature and has a siloxane group having high reactivity on the surface. Specifically, silica, silica was dried at high temperature - can be used are alumina and the like, which are typically _{Na 2 O, K 2 CO 3} , BaSO 4, Mg (NO 3) an oxide of _2, such as carbonate, sulfate, nitrate component .

The cocatalyst may include an alkylaluminoxane-based co-catalyst and / or a boron-based co-catalyst.

According to one embodiment of the present invention, the first and second metallocene compounds may be used as a catalyst for polymerization of propylene together with an alkylaluminoxane-based co-catalyst and a boron-based co-catalyst.

The alkylaluminoxane-based co-catalyst may be represented by the following general formula (3).

(3)

In Formula 3,

M 'is a Group 13 metal element;

R9 are the same or different from each other and are each an alkyl, alkenyl, alkylaryl, arylalkyl or aryl having 1 to 20 carbon atoms;

m may be an integer of 2 or more.

Preferably, the alkylaluminoxane-based promoter is a compound represented by the general formula (3), wherein R9 is methyl, ethyl, propyl, isopropyl, isopropenyl, (n-butyl), sec- butyl (sec -butyl), tert- butyl (tert -butyl), pentyl (pentyl), hexyl (hexyl), octyl (octyl), decyl (decyl), dodecyl (dodecyl), But are not limited to, tridecyl, tetradecyl, pentadecyl, hexadecyl, octadecyl, eikosyl, dokosyl, tetrakosyl, cyclohexyl cyclohexyl, cyclooctyl, phenyl, tolyl, or ethylphenyl; M 'can be aluminum.

In the above formula (3), m may be an integer of 2 or more, or an integer of 2 to 500, preferably 6 or more, or an integer of 6 to 300, more preferably 10 or more, .

The alkylaluminoxane-based co-catalyst may be a compound capable of acting as a Lewis acid capable of forming a bond through a Lewis acid-base interaction with a functional group introduced into a bridge group of the metallocene compound of Formula 1 And a metal element. The promoter compound of Formula 3 may be present in a linear, circular or network form. Examples of such a promoter compound may be at least one of methyl aluminoxane, ethyl aluminoxane, propyl aluminoxane, butyl aluminoxane, etc. have.

In the catalyst for polypropylene polymerization of the present invention, a co-catalyst containing a non-conjugated anion as a non-alkylaluminoxane-based catalyst may be used in addition to the alkylaluminoxane-based co-catalyst. In particular, according to an embodiment of the present invention, a boron-based promoter may be used as the non-alkylaluminoxane-based co-catalyst.

The boron-based promoter may be selected from the group consisting of dimethylanilinium tetrakis (pentafluorophenyl) borate, [HN (CH ₃ ) ₂ C ₆ H ₅ ] [B (C ₆ F ₅ ) ₄ ] ), Trityl tetakis (pentafluorophenyl) borate, [(C ₆ H ₅ ) ₃ C] [B (C ₆ F ₅ ) ₄ ]), and methyl anilinium tetrakis (Pentafluorodiphenyl) borate, [HN (CH ₃ ) (C ₆ H ₅ ) ₂ ] [B (C ₆ F ₅ ) ₄ ] Can be used.

The boron-based promoter enables stabilization of the metallocene compound to maintain activity in the polymerization. In particular, the metallocene compound used in the present invention has a tether, and leaching phenomenon does not occur due to the functional group, so that fouling does not occur and excellent activity can be exhibited. However, if there is no tether such as a known metallocene compound, there is a problem that fouling occurs mostly due to reaction with a leached catalyst precursor and a boron-based co-catalyst.

In the production process of the present invention, two promoters of an alkylaluminoxane-based promoter and a non-alkylaluminoxane-based boron-based promoter can be simultaneously carried to form a supported catalyst having improved activity. Also, the co-catalysts which did not cause adverse effects between the two co-catalysts were selected, and the optimum supporting ratio was confirmed through experiments.

In the process for preparing polypropylene according to an embodiment of the present invention, the metallocene compound is present in an amount of from about 40 to about 240 micromoles, preferably from about 80 to about 160 micromoles, per gram of carrier, Lt; / RTI >

In addition, the alkylaluminoxane-based cocatalyst may be supported in an amount of about 8 to about 25 mmol, preferably about 10 to about 20 mmol, based on 1 g of silica per weight of carrier, for example, 1 g of silica.

The boron based promoter may be supported in an amount ranging from about 50 to about 300 μmol, preferably about 64 to about 240 μmol, based on 1 g of silica per weight of carrier, based on 1 g of silica.

In the method for producing polypropylene according to an embodiment of the present invention. The catalyst has an improved catalytic activity over the supported catalyst having one kind of promoter, and even if the supporting condition of the metallocene compound is changed, that is, the reaction temperature, the reaction time, the type of silica and the loading amount of the metallocene compound The polypropylene can be produced with improved activity.

Here, the polymerization of propylene can be carried out by reacting at a temperature of about 25 to about 500 DEG C and a pressure of about 1 to about 100 kgf / cm < ² > for about 1 to about 24 hours. At this time, the polymerization reaction temperature is preferably about 25 ° C to about 200 ° C, and more preferably about 50 ° C to about 100 ° C. Further, the polymerization reaction pressure is preferably about 1 to about 70 kgf / cm ² , 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 according to the present invention comprises polymerizing propylene with a hybrid supported metallocene catalyst comprising a first metallocene compound of Formula 1 and a second metallocene compound of Formula 2, Followed by copolymerization by contacting the monomers.

The comonomers that can be used with the propylene include but are not limited to ethylene, 1-butene, 1-pentene, 1-hexene, 4-methyl-1-pentene, Hexadecene, 1-octadecene, 1-eicosene, and mixtures thereof, and preferably at least one selected from the group consisting of ethylene, 1-butene, 1-pentene, 1-pentene, or 1-octene.

When the comonomer is copolymerized with the propylene, the content of the comonomer may be about 1 to about 10 wt%, preferably about 1 to about 4 wt%, based on the weight of the propylene.

The process for producing the polypropylene can be carried out 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, and the like.

In the process for producing polypropylene according to the present invention, the catalyst may be an aliphatic hydrocarbon solvent having 5 to 12 carbon atoms suitable for the polymerization of the olefin monomer, for example, pentane, hexane, heptane, nonane, decane, An aromatic hydrocarbon solvent such as toluene or benzene, a hydrocarbon solvent substituted with a chlorine atom such as dichloromethane or chlorobenzene, or the like. It is preferable to use a small amount of water or air, which acts as a catalyst poison, by using a small amount of alkylaluminum.

According to another aspect of the present invention, there is provided a polypropylene obtained by the above-mentioned production method.

As described above, according to the present invention, by using the mixed supported metallocene catalyst comprising the first and second metallocene compounds, it is possible to obtain a catalyst having excellent catalytic activity when a conventional metallocene compound or a single supported metallocene catalyst is used A polypropylene having excellent processability and controlled xylene solubles can be obtained.

remind The polypropylene has low melting point and crystallization temperature and is excellent in workability, and can be used as a packaging container, a film for heat sealing, a sheet, or the like in which such characteristics are required.

According to an embodiment of the present invention, when the propylene polymerization process is carried out using the hybrid supported metallocene catalyst, the weight average molecular weight (Mw) of the resulting polypropylene is about 500,000 to 10,000,000, About 650,000 g / mol, or about 500,000 to about 600,000 g / mol, or about 550,000 to about 600,000 g / mol.

The polypropylene thus produced may have a molecular weight distribution (Mw / Mn) of about 4.0 or less, such as about 3.0 to about 4.0, preferably about 3.0 to about 3.5. By having a narrow molecular weight distribution as described above, it is possible to produce a product having a high transparency, particularly a flavor and odor problem peculiar to polypropylene.

Also, the xylene solubles (Xs) of the polypropylene may be in the range of about 0.5 to about 5.0 wt%, preferably about 1.0 to about 4.5 wt%, more preferably about 1.0 to about 4.0 wt% (tacticity). The xylene-soluble fraction is the content (% by weight) of the polymer soluble in the cooled xylene determined by dissolving the polypropylene in xylene and crystallizing the insoluble portion from the cooling solution. The xylene-soluble fraction contains a polymer chain of low stereoregularity, and the lower the content of the xylene-soluble fraction, the higher the stereoregularity. On the other hand, if the xylene-soluble fraction is too low, the mechanical properties such as the heat sealing property of the polypropylene may be difficult to manifest, and from this viewpoint, the weight range is preferable.

Further, the polypropylene produced according to the present invention exhibits high fluidity. For example, the polypropylene prepared according to the present invention has a melt index of at least about 0.5 g / 10 min, such as from about 0.5 to about 3.0 g / 10 min, preferably from about 0.5 to about 2.5 g / 10 min. It is possible to control the melt index according to the content of hydrogen in the polymerization process, so that polypropylene having an appropriate melt index can be produced according to the application.

In the present invention, matters other than those described above can be added or subtracted as required, and therefore, the present invention is not particularly limited thereto.

Hereinafter, preferred embodiments of the present invention will be described in order to facilitate understanding of the present invention. However, the following examples are provided only for the purpose of easier understanding of the present invention, and the present invention is not limited thereto.

<Examples>

&Lt; Synthesis Example: Synthesis of first metallocene compound >

Synthesis Example 1

Step 1: Preparation of (6-t -butoxyhexyl ) ( methyl ) -bis (2- methyl -4- (4-t- butylphenyl ) indenyl )) silane

150 g of 2-methyl-4- (4-t-butylphenyl) indene was placed in a 3 L Schlenk flask and dissolved in toluene / THF (10: 1, 1.73 L) at room temperature . After cooling the solution to -20 캜, 240 mL of n-butyllithium solution (n-BuLi, 2.5 M in hexane) was slowly added dropwise, and the mixture was stirred at room temperature for 3 hours. Thereafter, the reaction solution was cooled to -20 캜, and then 82 g of (6-t-butoxyhexyl) dichloromethylsilane and 512 mg of CuCN were slowly added dropwise. The reaction solution was warmed to room temperature, stirred for 12 hours, and 500 mL of water was added. Thereafter, the treated organic layer was separated, washed, dehydrated, and filtered through a MgSO _4. The filtrate was distilled under reduced pressure to obtain a yellow oil.

¹ H NMR (500 MHz, CDCl ₃ , 7.26 ppm): -0.09 to -0.05 (3H, m), 0.40-0.60 (2H, m), 0.80-1.51 (26H, m), 2.12-2.36 ), 3.20 ~ 3.28 (2H, m), 3.67-3.76 (2H, m), 6.81-6.83 (2H, m), 7.10 ~ 7.51

Step 2: Preparation of rac - [(6-t- butoxyhexylmethylsilanediyl ) -bis (2- methyl- 4- (4- t- butylphenyl ) indenyl)] hafnium dichloride

(6-t-butoxyhexyl) (methyl) bis (2-methyl-4- (4-t-butylphenyl)) indenylsilane prepared previously in a 3 L Schlenk flask, 1 L of ethyl ether was added and dissolved at room temperature. After the solution was cooled to -20 ° C, 240 mL of a n-butyllithium solution (n-BuLi, 2.5 M in hexane) was slowly added dropwise and the mixture was stirred at room temperature for 3 hours. Thereafter, the reaction solution was cooled to -78 deg. C, and then 92 g of hafnium chloride was added thereto. The reaction solution was warmed to room temperature, stirred for 12 hours, and the solvent was removed under reduced pressure. 1 L of dichloromethane was added, and then the insoluble inorganic salts and the like were removed by filtration. The filtrate was dried under reduced pressure, and again 300 mL of dichloromethane was added to precipitate crystals. The precipitated crystals were filtered and dried to obtain 80 g of rac - [(6-t-butoxyhexylmethylsilanediyl) -bis (2-methyl- 4- (4- t- butylphenyl) indenyl)] hafnium dichloride (Rac: meso = 50: 1).

^{1 H NMR (500 MHz, CDCl} 3, 7.26 ppm): 1.19 ~ 1.78 (37H, m), 2.33 (3H, s), 2.34 (3H, s), 3.37 (2H, t), 6.91 (2H, s) , 7.05-7.71 (14H, m)

&Lt; Synthesis Example: Synthesis of second metallocene compound >

Synthesis Example 2

[CH ₃ - (CH ₂ ) ₃ -C ₅ H ₄ ] ₂ ZrCl ₂ Manufacturing

n-Butyl chloride was reacted with NaCp to obtain n-BuCp. Thereafter, n-BuCp was dissolved in THF at -78 ° C, n-butyl lithium (n-BuLi) was added slowly, and the temperature was further raised to room temperature, followed by reaction for 8 hours. The lithium salt solution thus prepared was slowly added to a suspension solution of ZrCl ₄ (THF) ₂ (1.70 g, 4.50 mmol) / THF (30 ml) at -78 ° C. and further reacted at room temperature for 6 hours. All volatile materials were vacuum dried, and hexane solvent was added to the obtained oily liquid substance to be filtered. The filtered solution was vacuum dried, and hexane was added thereto to induce a precipitate at a low temperature (-20 ° C). The obtained precipitate was filtered off at a low temperature to obtain a (CH ₃ ) (CH ₂ ) ₃ -C ₅ H ₄ ] ₂ ZrCl ₂ compound in the form of a white solid. (Yield 50%)

&Lt; Preparation Example: Preparation of supported catalyst >

Production Example 1

After supporting methylaluminoxane on silica, the metallocene compound obtained in Synthesis Example 1 was carried thereon. Then, the metallocene compound obtained in Synthesis Example 2 was carried. The supported catalyst was supported on the boron-based catalyst to prepare a supported catalyst.

More specifically, 6 g of silica L203F was preliminarily weighed in a shrinking flask, and 60 mmol of methylaluminoxane (MAO) was added thereto, followed by reaction at 90 占 폚 for 24 hours. After precipitation, the upper layer was removed and washed once with toluene. 360 占 퐉 ol of the metallocene compound obtained in Synthesis Example 1 was dissolved in toluene and reacted at 70 占 폚 for 5 hours. After the completion of the reaction, the upper layer solution was removed and the remaining reaction product was washed with toluene. In addition, 120 占 퐉 ol of the metallocene compound obtained in Synthesis Example 2 was dissolved in toluene and reacted at 70 占 폚 for 2 hours.

384 占 퐉 ol of dimethylanilinium tetrakis (pentafluorophenyl) borate was reacted at 70 占 폚 for 5 hours. After completion of the reaction, the reaction product was washed with toluene, washed again with hexane, and vacuum-dried to obtain 7.5 g of a silica-supported metallocene catalyst in the form of solid particles.

Production Example 2

After supporting methylaluminoxane on silica, the metallocene compound obtained in Synthesis Example 1 was carried thereon. Then, the metallocene compound obtained in Synthesis Example 2 was carried. The supported catalyst was supported on the boron-based catalyst to prepare a supported catalyst.

More specifically, 6 g of silica L203F was preliminarily weighed in a shrinking flask, and 60 mmol of methylaluminoxane (MAO) was added thereto, followed by reaction at 90 占 폚 for 24 hours. After precipitation, the upper layer was removed and washed once with toluene. 360 占 퐉 ol of the metallocene compound obtained in Synthesis Example 1 was dissolved in toluene and reacted at 70 占 폚 for 5 hours. After the completion of the reaction, the upper layer solution was removed and the remaining reaction product was washed with toluene. In addition, 60 占 퐉 ol of the metallocene compound obtained in Synthesis Example 2 was dissolved in toluene, followed by reaction at 70 占 폚 for 2 hours.

336 占 퐉 ol of dimethylanilinium tetrakis (pentafluorophenyl) borate was reacted at 70 占 폚 for 5 hours. After completion of the reaction, the reaction product was washed with toluene, washed again with hexane, and vacuum-dried to obtain 7.5 g of a silica-supported metallocene catalyst in the form of solid particles.

<Examples of Propylene-Ethylene Random Polymerization>

Example 1

A 2 L stainless steel reactor was vacuum dried at 65 deg. C and then cooled. 3.0 mmol of triethyl aluminum was added at room temperature, and 770 g of propylene and 12,000 cc of ethylene were sequentially added. After stirring for 10 minutes, 80 mg of the mixed supported metallocene catalyst obtained in Preparation Example 1 was dissolved in 20 mL of hexane prescribed in TMA, and the reactor was charged under nitrogen pressure. After the reactor temperature was gradually raised to 70 ° C, the reactor was polymerized for 1 hour. After the completion of the reaction, unreacted propylene was bubbled.

Example 2

Propylene polymerization was carried out in the same manner as in Example 1, except that the mixed supported metallocene catalyst of Production Example 2 was used instead of the mixed supported metallocene catalyst obtained in Production Example 1.

The detailed operating conditions of Examples 1 and 2 are summarized in Table 1 below.

The amount of supported catalyst
(Unit: mg) The molar ratio of the first metallocene catalyst and the second metallocene catalyst Example 1 80 3: 1 Example 2 80 6: 1

&Lt; Measurement method of physical properties of polymer &

The physical properties of the polymers obtained in the above Examples 1 and 2 were measured in the following manner and are summarized in Table 2.

(1) Catalytic activity

The ratio of the weight of the polymer produced per gram of supported catalyst mass (kg PP) based on the unit time (h) and the weight of the polymer produced per total amount (μmol) of the supported metallocene compound in the supported catalyst ( kgPP).

(2) Melt Index (MI)

Measured at 230 占 폚 under a load of 2.16 kg according to ASTM D1238, and expressed as the weight (g) of the polymer melted for 10 minutes.

(3) Weight average molecular weight

The sample dissolved in TCB was heated up to 220 ° C and passed through a column tube at a rate of about 1.0 cc / min per sample to measure a relative molecular weight relative to a reference.

(4) Melting point (Tm)

The temperature was increased to 200 DEG C, held at that temperature for 5 minutes, then decreased to 30 DEG C, and the temperature was again increased to set the melting point at the top of the curve of DSC (Differential Scanning Calorimeter, TA). At this time, the temperature rise and fall speed was 10 ° C / min, and the melting point was measured at the second temperature rise.

(5) Crystallization temperature (Tc)

The DSC was used to determine the crystallization temperature from the curve obtained by decreasing the temperature under the same conditions as the melting point.

(6) Xylene solubles (Xylene Soluble)

Xylene was added to the sample, and the sample was preheated by heating at 135 ° C for 1 hour and cooling for 30 minutes. 1ml / min from OminiSec (Viscotek FIPA) equipment. When the base line of RI, DP and IP was stabilized by flowing Xylene for 4 hours at the flow rate, the concentration and injection amount of the pretreated sample were written and the peak area was calculated.

activation
(kg PP / g cat hr) Xylene-soluble fraction
(weight%) Melt Index
(g / 10 min) Weight average molecular weight
(g / mol) Molecular weight distribution Melting point
(° C) Crystallization temperature
(° C) Example 1 2.8 3.8 1.5 573,000 2.96 144.4 95.0 Example 2 3.0 2.6 1.6 562,000 2.85 144.3 95.6

Referring to Table 2, an embodiment of the present invention was able to produce a propylene polymer having a high melting point and a low melting point and a low crystallization temperature, and a suitable xylene soluble fraction.

Therefore, according to the production method of the present invention, it is expected that the propylene polymer having desired physical properties can be produced according to the amount of each metallocene catalyst due to the action of the two metallocene catalysts.

Claims (14)

There is provided a process for producing a polypropylene comprising polymerizing propylene in the presence of a mixed metallocene catalyst comprising a first metallocene compound represented by the following formula 1 and a second metallocene compound represented by the following formula 2 Manufacturing method:
[Chemical Formula 1]

In Formula 1,
X is the same or different halogen,
R1 is C6-C20 aryl substituted with alkyl having 1 to 20 carbon atoms,
R2, R3 and R4 are the same or different and each independently represents hydrogen, halogen, alkyl of 1 to 20 carbon atoms, alkenyl of 2 to 20 carbon atoms, alkylsilyl of 1 to 20 carbon atoms, silylalkyl of 1 to 20 carbon atoms, Alkoxysilyl having 1 to 20 carbon atoms, ether having 1 to 20 carbon atoms, silyl ether having 1 to 20 carbon atoms, alkoxy having 1 to 20 carbon atoms, aryl having 6 to 20 carbon atoms, alkylaryl having 7 to 20 carbon atoms, Lt; / RTI &gt;
A is carbon, silicon or germanium,
R5 is alkyl having 1 to 20 carbon atoms substituted with alkoxy having 1 to 20 carbon atoms,
R6 is hydrogen, alkyl of 1 to 20 carbon atoms or alkenyl of 2 to 20 carbon atoms.
(2)
_{(CpR 7) n (Cp'R 8} ) MQ 3-n
In Formula 2,
M is a Group 4 transition metal;
Cp and Cp 'are the same or different from each other, and each independently selected from the group consisting of cyclopentadienyl, indenyl, 4,5,6,7-tetrahydro-1-indenyl, and fluorenyl radical , Which may be substituted with hydrocarbons having 1 to 20 carbon atoms;
R 7 and R 8 are the same or different from each other and each independently represents hydrogen, alkyl having 1 to 20 carbon atoms, alkoxy having 1 to 10 carbon atoms, aryl having 6 to 20 carbon atoms, aryloxy having 6 to 10 carbon atoms, Alkenyl having 7 to 40 carbon atoms, arylalkyl having 7 to 40 carbon atoms, arylalkenyl having 8 to 40 carbon atoms, or alkynyl having 2 to 10 carbon atoms;
Q is selected from the group consisting of halogen, alkyl of 1 to 20 carbon atoms, alkenyl of 2 to 10 carbon atoms, alkylaryl of 7 to 40 carbon atoms, arylalkyl of 7 to 40 carbon atoms, aryl of 6 to 20 carbon atoms, A substituted or unsubstituted amino group, an alkylalkoxy group having 2 to 20 carbon atoms, or an arylalkoxy group having 7 to 40 carbon atoms,
n is 1 or 0;
The method of claim 1, wherein R1 is phenyl substituted by tert-butyl, R2, R3 and R4 are hydrogen, and R5 is 6-tert-butoxyhexyl, And R &lt; 6 &gt; is methyl.
The process for producing polypropylene according to claim 1, wherein the first metallocene compound represented by the formula (1) is a compound represented by the following structural formula:

The method according to claim 1, wherein the second metallocene compound represented by Formula 2 is a compound represented by the following structural formula:

The method of claim 1, wherein the first and second metallocene compounds are in a molar ratio of 10: 1 to 1: 1.
The hybrid metallocene catalyst according to claim 1, wherein the mixed metallocene catalyst is selected from the group consisting of a first metallocene compound represented by Formula 1, a second metallocene compound represented by Formula 2, an alkylaluminoxane- Wherein the catalyst is a supported catalyst supported on a carrier.
The process for producing polypropylene according to claim 6, wherein the alkylaluminoxane-based co-catalyst is at least one selected from the group consisting of methyl aluminoxane, ethyl aluminoxane, propyl aluminoxane, and butyl aluminoxane.
The method of claim 6, wherein the boron-based promoter is selected from the group consisting of dimethylanilinium tetrakis (pentafluorophenyl) borate, trityl tetrakis (pentafluorophenyl) borate, and methyl anilinium tetrakis (pentafluorodiphenyl ) Borate. &Lt; / RTI &gt;
The method of producing a polypropylene according to claim 6, wherein the carrier is at least one selected from the group consisting of silica, silica-alumina, and silica-magnesia.
The method of producing a polypropylene according to claim 1, further comprising a comonomer in addition to the propylene.
11. The process of claim 10, wherein the comonomer is selected from the group consisting of ethylene, 1-butene, 1-pentene, 1-hexene, 4-methyl- 1-hexadecene, 1-octadecene, 1-eicosene, and mixtures thereof.
A polypropylene obtained by the production method of claim 1.
The polypropylene according to claim 12, having a melt index (MI) of 0.5 to 3.0 g / 10 min when measured at 230 DEG C and 2.16 kg.
The polypropylene according to claim 12, having a xylene solubilized fraction (Xs) of 0.5 to 5.0% by weight.