KR20180054357A - Method for preararing polypropylene - Google Patents

Abstract

The present invention provides a method for producing a polypropylene, which can obtain a polymer which can be easily carried without fouling during the polymerization by effectively carrying a catalyst having no tether, and moreover, which generates a little generation of fine particles as there is no catalyst to be etched in a carrier and can improve the strength and durability of a polymer.

Description

METHOD FOR PREPARING POLYPROPYLENE [0002]

The present invention relates to a process for producing a polymer which is capable of obtaining a polymer powder in the form of a powder without fouling during the polymerization process and which has no catalyst to be etched in the carrier, Propylene. ≪ / RTI >

Ziegler-Natta catalysts of titanium or vanadium compounds have been widely used for the commercial production of polyolefins. Although the Ziegler-Natta catalysts have high activity, they have a wide molecular weight distribution of the produced polymers because of their high activity, The uniformity of the composition is not uniform and there is a limit in ensuring desired physical properties.

Recently, a metallocene catalyst in which a transition metal such as titanium, zirconium, or hafnium and a ligand containing a cyclopentadiene functional group are bonded has been developed and widely used. The metallocene compound is generally activated by using aluminoxane, borane, borate or other activator. For example, a metallocene compound having a ligand containing a cyclopentadienyl group and two sigma chloride ligands uses aluminoxane as an activator.

Such metallocene catalysts have the advantage of being able to control the microstructure of polymers produced, unlike the heterogeneous Ziegler-Natta catalysts. However, the above metallocene catalyst has a disadvantage in that it is difficult to synthesize and has a low melting point (Tm) relative to Ziegler-Natta.

In addition, the metallocene catalyst for polypropylene, which is currently being developed, undergoes a carrying process in order to be applied to bulk polymerization. When the carrying process is difficult and the loading is not performed well, a process problem such as fouling occurs .

In general, the metallocene supported catalyst has a problem of pre-polymerization before the polymerization in order to avoid process problems.

Therefore, it is still necessary to develop a catalyst for olefin polymerization which is easy to carry out without fouling and has excellent activity.

It is an object of the present invention to provide a supported metallocene catalyst capable of obtaining a polymer powder in the form of a powder without fouling during the polymerization process and having no catalyst to be etched in the support, And a method for producing polypropylene using the same.

The present invention relates to a process for producing a polypropylene comprising homopolymerizing a propylene monomer in the presence of a metallocene supported catalyst and hydrogen gas,

The metallocene supported catalyst may contain,

a) supporting the cocatalyst on the carrier; And

b) supporting the metallocene compound represented by the following general formula (1) on a carrier carrying the promoter; Or ii) pre-activating by adding a metallocene compound represented by the general formula (1) and a cocatalyst.

A process for producing polypropylene is provided.

[Chemical Formula 1]

(In the formula 1,

R ₁ to R ₁₂ each independently represent hydrogen, an alkyl group having 1 to 10 carbon atoms, an alkenyl group having 2 to 10 carbon atoms, an alkynyl group having 2 to 10 carbon atoms, an alkoxy group having 1 to 20 carbon atoms, an aryl group having 6 to 20 carbon atoms , A cycloalkyl group having 3 to 20 carbon atoms, an alkylaryl group having 7 to 20 carbon atoms, and an arylalkyl group having 7 to 20 carbon atoms, wherein the cycloalkyl group, alkylaryl group, or arylalkyl group has a carbon number A branched or straight-chain alkyl group having 1 to 20 carbon atoms,

R ₁₃ and R ₁₄ are each a hydrogen atom, an alkyl group having 1 to 20 carbon atoms, an alkenyl group having 2 to 20 carbon atoms, an alkylaryl group having 7 to 30 carbon atoms, an arylalkyl group having 7 to 30 carbon atoms or an aryl group having 6 to 30 carbon atoms,

A is a bridge group connecting an indenyl group as a group 14 element,

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

The carrier may include heat treating the carrier for 12 to 36 hours at a temperature of 200 to 600 DEG C such that the carrier surface has a hydroxyl group content of 0.5 to 1.5 mmol / g.

In step a), the cocatalyst may be supported in an amount of 8 to 25 mmol based on 1 g of silica.

In step b) i), the metallocene compound of formula 1 may be supported in an amount of 30 to 100 μmol based on 1 g of silica.

The mixture of the metallocene compound represented by the formula (1) and the cocatalyst in the step (b) ii) may be contained in an amount of 30 to 100 μmol and 0.5 to 3 mmol, respectively, based on 1 g of the carrier.

Further, in the present invention, after the step b), the method may further include adding 2 to 5% by weight of an additive based on 1 g of the carrier.

The cocatalyst may include an alkylaluminoxane-based cocatalyst having 1 to 10 carbon atoms.

Wherein R ₁ to R ₁₂ are each independently an arylalkyl group having 7 to 20 carbon atoms substituted with hydrogen or tert-butoxy, R ₁₃ and R ₁₄ are each independently an alkyl group having 1 to 10 carbon atoms, and A is Si, and X may be halogen.

In Formula 1, R ₃ and R ₁₀ are each independently an arylalkyl group having 7 to 20 carbon atoms substituted with a tert-butyl group, and R ₁₃ and R ₁₄ are each independently a methyl group.

The hydrogen gas may be supplied at a rate of 100 to 5000 mol.ppm.

The polypropylene according to the present invention may have a molecular weight distribution (MWD) of 1.5 to less than 3 as measured by GPC.

According to the present invention, by using a supported metallocene catalyst that does not include a tether group in the catalytic skeleton in the preparation of polypropylene according to a specific supporting condition, the polymer can be easily supported without fouling during the polymerization process, , And there can be provided a method capable of improving the strength and durability of the polymer particularly without generation of fine particles.

FIG. 1 is a graph comparing the molecular weight distributions of Examples 2 to 3 and Comparative Example 2. FIG.

Hereinafter, the present invention will be described in more detail. The terms and words used in the present specification and claims should not be construed as limited to ordinary or dictionary terms and the inventor may appropriately define the concept of the term in order to best describe its invention It should be construed as meaning and concept consistent with the technical idea of the present invention.

Also, " comprising "as used herein should be interpreted as specifying the presence of particular features, integers, steps, operations, elements and / or components, It does not exclude the presence or addition of an ingredient.

Hereinafter, a method for producing polypropylene according to embodiments of the present invention will be described in detail.

According to an embodiment of the present invention, in the process for producing a polypropylene comprising homopolymerizing a propylene monomer in the presence of a metallocene supported catalyst and hydrogen gas, the metallocene supported catalyst is characterized in that a) Supporting the catalyst; And b) supporting the metallocene compound represented by the following formula (1) on the support carrying the promoter; Or ii) adding a metallocene compound represented by the general formula (1) and a cocatalyst and pre-activating the metallocene compound.

[Chemical Formula 1]

(In the formula 1,

R ₁ to R ₁₂ each independently represent hydrogen, an alkyl group having 1 to 10 carbon atoms, an alkenyl group having 2 to 10 carbon atoms, an alkynyl group having 2 to 10 carbon atoms, an alkoxy group having 1 to 20 carbon atoms, an aryl group having 6 to 20 carbon atoms , A cycloalkyl group having 3 to 20 carbon atoms, an alkylaryl group having 7 to 20 carbon atoms, and an arylalkyl group having 7 to 20 carbon atoms, wherein the cycloalkyl group, alkylaryl group, or arylalkyl group has a carbon number A branched or straight-chain alkyl group having 1 to 20 carbon atoms,

R ₁₃ and R ₁₄ are each a hydrogen atom, an alkyl group having 1 to 20 carbon atoms, an alkenyl group having 2 to 20 carbon atoms, an alkylaryl group having 7 to 30 carbon atoms, an arylalkyl group having 7 to 30 carbon atoms or an aryl group having 6 to 30 carbon atoms,

A is a bridge group connecting an indenyl group as a group 14 element,

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

The present invention provides a supported metallocene catalyst in which a catalyst having no tether in a catalyst structure is supported on a carrier and has improved loading conditions. When such a supported catalyst is used, The polypropylene capable of exhibiting a narrow MWD can be produced. These polymers can have improved strength and durability.

In addition, in the present invention, the supported catalyst is prepared by controlling the amount of hydroxy in the carrier or by pre-activating the catalyst differently from the conventional method. With the above-mentioned pre-activation method, a narrow molecular weight distribution (narrow MWD) can be realized during polymerization since the catalyst is homogeneously activated in solution and then carried. Particularly, there is a problem that the existing catalyst changes proportionally as the amount of supported catalyst increases or decreases. However, in the case of the tetherless catalyst of the present invention, even if the amount of the supported catalyst is reduced by about 50%, a polymer having a narrow molecular weight distribution can be easily obtained without any difference in activity. Therefore, the morphology of the polymer can be improved in the present invention. Further, according to the present invention, by using a supported metallocene catalyst having improved loading conditions for polymerization of polypropylene, it is possible to obtain a polymer in the form of powder without fouling during the polymerization, and there is no catalyst to be etched in the carrier, There is little occurrence.

In the method for producing polypropylene of the present invention, the supported metallocene catalyst used for the polymerization is preferably prepared according to the method of steps a) and b).

The step a) is a step for supporting the cocatalyst on the carrier.

The promoter used in the present invention may be an alkyl aluminoxane-based promoter, and the alkyl aluminoxane promoter may be represented by the following formula (2).

(2)

In Formula 2,

M ² is a Group 13 metal element;

R ⁵ are the same or different 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.

The alkylaluminoxane-based promoter is preferably a compound wherein R ⁵ in the general formula (2) is methyl, ethyl, propyl, isopropyl, isopropenyl, n- butyl (n-butyl), sec- butyl (sec -butyl), tert- butyl (tert -butyl), pentyl (pentyl), hexyl (hexyl), octyl (octyl), decyl (decyl), dodecyl (dodecyl) Tridecyl, tetradecyl, pentadecyl, hexadecyl, octadecyl, eikosyl, dokosyl, tetrakosyl, cyclododecyl, cyclohexyl, Cyclohexyl, cyclooctyl, phenyl, tolyl, or ethylphenyl; M ² may be aluminum.

In Formula 2, 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, or an integer of 10 to 100.

The alkylaluminoxane co-catalyst may include a metal element capable of forming a bond through interaction with a functional group introduced into a bridge group of the metallocene compound of Formula 1. The promoter compound of Formula 2 may exist in a linear, circular or network form. Examples of the promoter compound include at least one of methyl aluminoxane, ethyl aluminoxane, propyl aluminoxane and butyl aluminoxane. have.

Also, in the step a), the cocatalyst may be supported in an amount of 8 to 25 mmol, preferably 10 to 20 mmol, based on 1 g of silica per weight of carrier, for example.

Particularly, the carrier may be any of those conventionally used in the technical field to which the present invention belongs, so that it is not particularly limited, but at least one carrier selected from the group consisting of silica, silica-alumina and silica-magnesia may be used. The carrier may be used by drying at a high temperature. Preferably, the step of preparing the a) carrier comprises a step of heat treating the carrier for 12 to 36 hours at a temperature of 200 to 600 ° C so as to have a hydroxyl group content of 0.5 to 1.5 mmol / g on the carrier surface . More preferably, the support is calcined at a temperature of 200 to 300 ° C to increase the hydroxyl group content on the surface of the support, so that the metallocene compound can be effectively supported even when using a tetherless catalyst.

The carrier may further contain oxides, carbonates, sulfates and nitrate components such as Na ₂ O, K ₂ CO ₃ , BaSO ₄ and Mg (NO ₃ ) ₂ .

Also, the step a) may be carried out at a temperature of 90 to 130 ° C for 1 to 16 hours with stirring.

Also, the step b) is a step for supporting the metallocene compound on the support carrying the promoter.

Specifically, the method of the present invention comprises the steps of: i) supporting a metallocene compound represented by the following formula (1) on a support carrying the above promoter; Or ii) pre-activation by adding a metallocene compound represented by the general formula (1) and a cocatalyst.

Accordingly, the metallocene compound of Formula 1 does not include a tether as in the above-described structure, and even if the tether is not included, the amount of the hydroxy group of the support may be controlled or may be controlled by a pre- It is possible to improve the catalytic activity and to prevent the fouling phenomenon during the polymerization process.

According to one embodiment of the present invention, in step b) i), the metallocene compound of formula 1 is added in an amount of 30 to 100 μmol, preferably 50 to 70 μmol, based on 1 g of silica per weight of carrier, By weight. At this time, if the molar ratio deviates from the above range, there is a problem of reduction in activity and fouling.

According to another embodiment of the present invention, the mixture of the metallocene compound represented by the general formula (1) and the cocatalyst in the step b) ii) is added in a proportion of 30 to 100 μmol and 0.5 to 3 mmol, .

In the present invention, the step b) may be carried out at a temperature of 50 to 70 ° C for 5 to 16 hours with stirring.

In the present invention, each of the substituents defined in Formula 1 will be described in detail as follows.

The alkyl group having 1 to 20 carbon atoms may include a linear or branched alkyl group, and the alkenyl group and alkynyl group having 2 to 20 carbon atoms may each include a straight chain or branched chain alkenyl group and an alkynyl group.

The aryl group is preferably an aromatic ring having 6 to 20 carbon atoms. Specific examples thereof include phenyl, naphthyl, anthracenyl, pyridyl, dimethylanilinyl, and anisole. However, the aryl group is not limited thereto.

The alkylaryl group means an aryl group having at least one straight or branched alkyl group having 1 to 20 carbon atoms, and the arylalkyl group means a straight or branched alkyl group having at least one aryl group having 6 to 20 carbon atoms introduced thereto.

The halogen group means fluorine (F), chlorine (Cl), bromine (Br) and iodine (I).

In the ligand compound of this embodiment, R ₁₀ in the formula (1) may be an alkyl group having 1 to 20 carbon atoms substituted with an alkoxy group having 1 to 20 carbon atoms. Herein, R ₁₀ may mean an alkyl group having 1 to 20 carbon atoms substituted with a linear or branched alkoxy group having 1 to 20 carbon atoms. In R ₁₀ , the alkoxy group may be substituted at the terminal or side chain of the alkyl group, preferably at the terminal.

More preferably, R ₁₀ is an alkyl group having 1 to 20 carbon atoms substituted with tert-butoxy, and R ₁₁ may be an alkyl group having 1 to 20 carbon atoms. Preferably, R ₁₀ is tert-butoxy-hexyl and R ₁₁ can be methyl.

It is preferable that A is silicon among the Group 14 elements.

X may be halogen. Preferably, X may be chlorine.

Preferable examples of the metallocene compound represented by the above formula (1) are as follows.

That is, in the present invention, each of R ₁ to R ₁₂ is independently an arylalkyl group having 7 to 20 carbon atoms substituted with hydrogen or tert-butoxy, and R ₁₃ and R ₁₄ are each independently a group having 1 to 10 carbon atoms Alkyl group, A is Si, and X is halogen.

In the above Formula 1, R ₃ and R ₁₀ are each independently an arylalkyl group having 7 to 20 carbon atoms substituted with a tert-butyl group, and R ₁₃ and R ₁₄ are each independently a methyl group. In the above formula (1), R ₃ and R ₁₀ may each independently be tert-butyl-hexyl.

In the present invention, after the step b), an additive may be further added and its content is not limited. Preferably, after step b), the method may further comprise adding 2 to 5% by weight of an additive based on 1 g of the carrier. Also, when performing the step b) ii), the additive can be added after the step b) ii).

The additive may be an antistatic agent, which may prevent the generation of static electricity in the reactor, but may also act as a catalyst modifier. Such additives can be used by purchasing products well known in the art and include, but are not limited to, Atmer 163 TM, and "Satdis 450 ".

After the step b), a decantation process according to a general method may be further performed. Preferably, after the metallocene compound and the cocatalyst are supported on the support, the upper layer solution is removed from the reaction solution, and the remaining reaction product is decanted using the solvent at least once or more Step < / RTI >

In the method for preparing the supported metallocene catalyst of the present invention, the reaction can proceed under an inert atmosphere.

In preparing the supported metallocene catalyst, a solvent may further be used.

As the solvent, any solvent known to be usable in the catalyst composition for olefin polymerization may be used without limitation, for example, aliphatic hydrocarbon solvents such as pentane, hexane, heptane, nonane, decane and isomers thereof; Aromatic hydrocarbon solvents such as toluene, xylene and benzene; Or a hydrocarbon solvent substituted with a chlorine atom such as dichloromethane or chlorobenzene. The content of the solvent in the catalyst composition may be appropriately controlled depending on the characteristics of the catalyst composition used and the conditions of the production process of the olefin polymer to be used.

The activity of the supported catalyst of the present invention prepared according to the above is preferably 5 kg / m < 2 >, calculated as the ratio of the weight (kg) of the polymer produced per gram of catalyst unit weight (g) gCat · hr or 5 to 20 kg / gCat · hr, and preferably 10 kg / gCat · hr or more.

On the other hand, the polymerization reaction of the polypropylene according to the present invention is not limited to the polymerization process known as the polymerization reaction of olefin monomers such as a continuous solution polymerization process, a bulk polymerization process, a suspension polymerization process, a slurry polymerization process or an emulsion polymerization process And homopolymerization can be preferably carried out according to the above process.

Examples of olefin monomers that can be polymerized using the metallocene compounds and the cocatalyst include ethylene, alpha-olefin, cyclic olefin, etc., and diene olefin monomers or triene olefin monomers having two or more double bonds Can also be polymerized. Specific examples of the monomer include ethylene, propylene, 1-butene, 1-pentene, 4-methyl-1-pentene, 1-hexene, Butene, dicyclopentadiene, 1,4-butadiene, 1,4-butadiene, 1,3-butadiene, 1,3-butadiene, Pentadiene, 1,6-hexadiene, styrene, alpha-methylstyrene, divinylbenzene, 3-chloromethylstyrene and the like. These two or more monomers may be mixed and copolymerized. When the polyolefin is a copolymer of ethylene and another comonomer, the monomer constituting the copolymer is selected from the group consisting of propylene, 1-butene, 1-hexene, 4-methyl- Or more of the comonomer.

Here, the polymerization conditions of the polypropylene can be carried out by reacting at a temperature of 25 to 500 DEG C and a pressure of 1 to 100 kgf / cm < 2 > for 1 to 24 hours. At this time, the polymerization reaction temperature is preferably 25 to 200 ° C, more preferably 50 to 100 ° C. The polymerization reaction pressure is preferably 1 to 70 kgf / cm 2, and more preferably 5 to 40 kgf / cm 2. The polymerization reaction time is preferably 1 to 5 hours.

The above-mentioned polymerization process can control the molecular weight range of the polymer product finally produced according to the hydrogenated or not added conditions, but hydrogen is preferably added.

Therefore, the hydrogen gas may be supplied at 100 to 5000 mol.ppm. Specifically, the hydrogen content added to the polymerization process is in the range of 0.07 L to 4 L under 1 atm of the reactor condition, or at a pressure of 1 bar to 40 bar or in a range of from 168 ppm to 5,000 ppm Can be supplied.

In the polymerization reaction, the supported metallocene catalyst may be used in a state of being dissolved or diluted in a solvent such as pentane, hexane, heptane, nonane, decane, toluene, benzene, dichloromethane, chlorobenzene and the like. At this time, by treating the solvent with a small amount of alkylaluminum or the like, a small amount of water or air that can adversely affect the catalyst can be removed in advance.

The polypropylene prepared according to the above-described method may have a weight average molecular weight of 50,000 to 600,000 as measured by GPC. In particular, the polypropylene of the present invention may have a molecular weight distribution (MWD) as measured by GPC of 2.4 or less, and preferably a molecular weight distribution (MWD) of 1.5 to less than 3. And, the melt index (MI) of the polypropylene may be 1 to 2000 (g / 10 min).

Hereinafter, preferred embodiments of the present invention will be described in detail. It should be understood, however, that these examples are for illustrative purposes only and are not to be construed as limiting the scope of the present invention.

< Comparative Example  1 and 2>

(1) Preparation of supported catalyst

Silica gel (SP2410, 10 g) was placed in a 500 mL buchi glass under Ar, MAO (62 mL, 8 mmol) was slowly injected at 25 캜 and stirred at 90 캜 for 18 hours for reaction.

Thereafter, when the reaction was terminated and a precipitate formed, the upper layer was removed and washed with toluene. Then, 70 mu mol of the metallocene compound having the above structure was dissolved in toluene, and the reaction was carried out at 50 DEG C for 5 hours. After the completion of the reaction and after completion of the precipitation, the upper layer solution was removed, and the remaining reaction product was washed with toluene, washed again with hexane, and vacuum-dried to obtain a solid (0.3 g, 3 wt.%) Dissolved in hexane. 12 g of silica-supported metallocene catalyst in the form of particles was obtained.

(2) homopolymerization of propylene

A 2 L stainless steel reactor was vacuum dried at 65, cooled, and triethylaluminum (3 mL), hydrogen (5 bar pressure conditions) and propylene (770 g) were sequentially added at room temperature. After stirring for 10 minutes, the metallocene supported catalyst prepared above was dissolved in 20 mL of TMA-prescribed hexane and introduced into the reactor under nitrogen pressure. The temperature of the reactor was then slowly raised to 70 ° C and then polymerized for 1 hour. After the completion of the reaction, unreacted propylene was bubbled. At this time, they were classified into Comparative Examples 1 and 2 depending on the amount of hydrogen injected and the amount of catalyst.

< Example  1 and 2>

(1) Preparation of supported catalyst

Silica gel (952X, 10 g) was placed in 500 mL buchi glass under Ar and MAO (100 mL, 13 mmol) was slowly added at 25 ° C and stirred at 90 ° C for 18 hours.

Thereafter, when the reaction was terminated and a precipitate formed, the upper layer was removed and washed with toluene. Then, 90 mu mol of the metallocene compound having the above structure was dissolved in toluene, and the mixture was reacted at 50 DEG C for 5 hours. After the completion of the reaction and after completion of the precipitation, the upper layer solution was removed, and the remaining reaction product was washed with toluene, washed again with hexane, and vacuum-dried to obtain a solid (0.3 g, 3 wt.%) Dissolved in hexane. Thereby obtaining 13 g of silica-supported metallocene catalyst in particle form.

(2) homopolymerization of propylene

A 2 L stainless steel reactor was vacuum dried at 65, cooled, and triethylaluminum (3 mL), hydrogen (5 bar pressure conditions) and propylene (770 g) were sequentially added at room temperature. After stirring for 10 minutes, 25 mg of the metallocene supported catalyst prepared above was dissolved in 20 mL of TMA-prescribed hexane and introduced into the reactor under nitrogen pressure. The temperature of the reactor was then slowly raised to 70 ° C and then polymerized for 1 hour. After the completion of the reaction, unreacted propylene was bubbled. At this time, it was classified into Examples 1 and 2 according to the amount of hydrogen injected.

< Example  3 and 4>

(1) Preparation of supported catalyst

Silica gel (952X, 10 g) was placed in 500 mL buchi glass under Ar, MAO (77 mL, 10 mmol) was slowly injected at 25 째 C and stirred at 90 째 C for 18 hours.

Thereafter, when the reaction was terminated and a precipitate formed, the upper layer was removed and washed with toluene. Then, 50 μmol of the metallocene compound having the above structure was dissolved in toluene, and 3 mmol of MAO was added thereto. The mixture was stirred to preactivate at 25 ° C. for 30 minutes, and the mixture was reacted at 50 ° C. for 5 hours.

Stadis (0.25 g, 2.5 wt%) dissolved in hexane was added to the reaction. After completion of the reaction, the upper layer solution was removed, and the remaining reaction product was washed with toluene, washed again with hexane, Thereby obtaining 15 g of silica-supported metallocene catalyst in the form of particles.

(2) homopolymerization of propylene

A 2 L stainless steel reactor was vacuum dried at 65 and then cooled and triethylaluminum (3 mL), hydrogen 827 (mol.ppm) (5 bar pressure condition) and propylene (770 g) were added sequentially at room temperature. After stirring for 10 minutes, 30 mg of the metallocene supported catalyst prepared above was dissolved in 20 mL of TMA-prescribed hexane and introduced into the reactor under nitrogen pressure. The temperature of the reactor was then slowly raised to 70 ° C and then polymerized for 1 hour. After the completion of the reaction, unreacted propylene was bubbled. At this time, according to the amount of hydrogen injected, it was classified into Examples 3 to 4.

< Experimental Example >

Measurement of physical properties of polymer

The properties of the homopolypropylene prepared in Examples 1 to 4 and Comparative Examples 1 and 2 were measured by the following methods, and the results are shown in Table 1. The results of molecular weight distributions of Examples 2 to 3 and Comparative Example 2 are shown in comparison with FIG.

1) Catalytic activity: Calculated as the ratio of the weight of polymer produced per kg of supported catalyst (g) based on unit time (h) (kg PP).

2) Melt Flow Rate (MFR): measured according to ASTM D-1238 under the conditions of a load of 230 kg and a load of 2.16 kg.

3) Melting point (Tm) of the polymer: The melting point of the polymer was measured using a differential scanning calorimeter (DSC, DSC 2920, manufacturer: TA instrument). Specifically, the polymer was heated up to 220 ° C., and the temperature was maintained for 5 minutes. After cooling to 20 ° C., the temperature was increased again. The temperature rising rate and the falling rate were adjusted to 10 / min.

4) Mw and MWD: Weight average molecular weight and molecular weight distribution of homopolypropylene were measured by GPC in a conventional manner.

Amount of catalyst
(mg) H2 Yield Activity MFR DSC GPC (mol.ppm) (g) (kg / g.hr) (g / min) Tm Mw MWD Comparative Example 1 30 331 308.3 10.3 9.1 150.9 284,000 3.02 Comparative Example 2 20 827 333.5 16.7 26.7 149.9 210,000 3.35 Example 1 25 331 280.9 11.2 2.1 151.9 444,000 2.35 Example 2 25 827 252.6 10.1 25.6 150.5 232,000 2.72 Example 3 30 827 391.1 13.0 7.0 151.9 293,000 2.35 Example 4 30 1500 375.1 12.5 25.4 151.1 190,000 2.42

As shown in Table 1 and FIG. 1, Examples 1 to 4 are superior to Comparative Examples 1 and 2 in that a metallocene supported catalyst prepared according to a specific supporting method is used to obtain a polymer having a high MWD and a narrow MWD Polypropylene). &Lt; / RTI &gt;

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

Claims (11)

In a process for producing a polypropylene comprising homopolymerizing a propylene monomer in the presence of a metallocene supported catalyst and hydrogen gas,
The metallocene supported catalyst may contain,
a) supporting the cocatalyst on the carrier; And
b) supporting the metallocene compound represented by the following general formula (1) on a carrier carrying the promoter; Or ii) pre-activating by adding a metallocene compound represented by the general formula (1) and a cocatalyst.
A process for producing polypropylene.
[Chemical Formula 1]

(In the formula 1,
R ₁ to R ₁₂ each independently represent hydrogen, an alkyl group having 1 to 10 carbon atoms, an alkenyl group having 2 to 10 carbon atoms, an alkynyl group having 2 to 10 carbon atoms, an alkoxy group having 1 to 20 carbon atoms, an aryl group having 6 to 20 carbon atoms , A cycloalkyl group having 3 to 20 carbon atoms, an alkylaryl group having 7 to 20 carbon atoms, and an arylalkyl group having 7 to 20 carbon atoms, wherein the cycloalkyl group, alkylaryl group or arylalkyl group has a carbon number A branched or straight-chain alkyl group having 1 to 20 carbon atoms,
R ₁₃ and R ₁₄ are each a hydrogen atom, an alkyl group having 1 to 20 carbon atoms, an alkenyl group having 2 to 20 carbon atoms, an alkylaryl group having 7 to 30 carbon atoms, an arylalkyl group having 7 to 30 carbon atoms or an aryl group having 6 to 30 carbon atoms,
A is a bridge group connecting an indenyl group as a group 14 element,
And X is each independently a halogen or an alkyl group having 1 to 20 carbon atoms)
The method according to claim 1,
Wherein the carrier comprises a step of heat treating the carrier for 12 to 36 hours at a temperature of 200 to 600 占 폚 so as to have a hydroxyl group content of 0.5 to 1.5 mmol / g on the carrier surface.
A process for producing polypropylene.
The method according to claim 1,
Wherein the cocatalyst is supported in a range of 8 to 25 mmol based on 1 g of silica in the step a).
The method according to claim 1,
Wherein the metallocene compound of formula (1) is supported in an amount of 30 to 100 μmol based on 1 g of silica in step (b) i).
5. The method of claim 4,
Wherein the mixture of the metallocene compound represented by the formula (1) and the cocatalyst in the step (b) ii) is contained in an amount of 30 to 100 μmol and 0.5 to 3 mmol, respectively, based on 1 g of the carrier.
The method according to claim 1,
Further comprising, after step b), 2 to 5% by weight of an additive based on 1 g of the carrier.
The method according to claim 1,
Wherein the promoter comprises an alkylaluminoxane co-catalyst having 1 to 10 carbon atoms.
The method according to claim 1,
Wherein R ₁ to R ₁₂ are each independently an arylalkyl group having 7 to 20 carbon atoms substituted with hydrogen or tert-butoxy,
R ₁₃ and R ₁₄ are each independently an alkyl group having 1 to 10 carbon atoms,
A is Si,
X is a halogen,
A process for producing polypropylene.
The method according to claim 1,
Wherein R ₃ and R ₁₀ are each independently an arylalkyl group having 7 to 20 carbon atoms substituted with a tert-butyl group,
R ₁₃ and R ₁₄ are each independently a methyl group,
A process for producing polypropylene.
The method according to claim 1, wherein the hydrogen gas is introduced at 100 to 5000 mol.ppm.
The process according to claim 1, wherein the polypropylene has a molecular weight distribution (MWD) of 1.5 to less than 3 as measured by GPC.

Images