KR19980045994A - Method for producing polypropylene having various distributions by sequential addition of metallocene catalyst and Ziegler-Natta catalyst - Google Patents

Abstract

The present invention relates to a method for producing a polypropylene capable of controlling the properties and molecular weight distribution by sequentially adding a metallocene catalyst and a Ziegler-Natta catalyst.

In the present invention, in the preparation of polypropylene having various molecular weights, molecular weight distribution and melting point by polymerization, a metallocene catalyst and a Ziegler-Natta catalyst are sequentially added, and as a co-catalyst of the Ziegler-Natta catalyst, a general formula R _n 1 or a mixture thereof selected from organoaluminum compounds or aluminoxanes represented by AlY _3-n , wherein R is a hydrocarbon having 1-20 carbon atoms, Y is halogen, and 0≤n≤3. It is characterized by using aluminoxane as a cocatalyst of the metallocene catalyst.

Polypropylene produced by the present invention has a variety of properties and molecular weight distribution, can be molded and used in a variety of products such as plates, films, containers, fibers.

Description

Method for producing polypropylene having various distributions by sequentially adding a metallocene catalyst and a Ziegler-Natta catalyst

The present invention relates to a method for preparing a polypropylene capable of controlling the properties and molecular weight distribution by sequentially adding a metallocene catalyst and a Ziegler-Natta catalyst, and more particularly, using a Ziegler-Natta catalyst and a metallocene catalyst. In this regard, the present invention relates to a method for producing polyffhylene having different properties and molecular weight distribution by varying the order of administration during polymerization, the polymerization time of each catalyst, and the use of a promoter.

The Ziegler-Natta catalyst system refers to a catalyst system composed of a combination of a main catalyst composed mainly of transition metal compounds, a cocatalyst composed of an organic metal compound, and an electron donor. This catalyst has been developed in the direction of improving polymerization activity and stereoregularity until now, and the properties and molecular weight distribution of the resulting polypropylene are determined when its components and production methods are determined. Therefore, in order to change the properties and molecular weight distribution of the polypropylene, it should be accompanied by a change in the constituents and a polymerization method in the preparation of the catalyst.

Metallocene catalysts are a type of organometallic compound and are known as homogeneous catalysts. Metallocene catalysts generally exhibit high activity and have a single polymerization activity point so that the M _W / M _n value of the polymer is not as narrow as about 2, and the copolymer distribution of the copolymer is uniform. In particular, it is known to enable the polymerization or copolymerization of cycloolefins such as cyclopentene and norborene. Metallocene catalysts show various changes in the stereospecificity, molecular weight, and catalytic activity of polymers according to the structure change of ligand in olefin polymerization. The metallocene catalyst is largely composed of four parts of a central metal, π ligand, bridge structure, and σ ligand. The polymerization mechanism of olefin is affected by the structural change of the metallocene catalyst and the electronic and steric effect by the change of the core metal and ligand, and thus the activity of the catalyst, molecular weight and stereospecificity of the polymerized polymer are changed. .

The molecular weight and molecular weight distribution of the polymer are important factors in determining the physical, mechanical and rheological properties of the polymer. Molecular weight has a great influence on the mechanical properties, while molecular weight distribution is the center of polymer design because it controls the melt processability as a factor controlling the rheological properties of the polymer. In general, when the molecular weight of the polyolefin is large, it is known that the toughness, strength, stress cracking resistance due to the environment is increased, but processing is difficult due to the high melt viscosity. The molecular weight distribution requires different properties depending on the type of polymer to be produced. In general, the polymer having a narrow molecular weight distribution has a poor flow rate in the processing process because the melt viscosity decreases less with the shear rate than the polymer having a wide molecular weight distribution. Therefore, a narrower molecular weight distribution is required for fiber extrusion or thin plate injection, and a wider molecular weight distribution is required for general injection or extrusion. Therefore, in order to satisfy various processing conditions while maintaining the physical properties of the polymer, it is necessary to control the molecular weight distribution. In particular, by having a molecular weight distribution in the form of bimodal distribution, it is possible to increase the mechanical strength to the high molecular weight portion and to control the processability to the low molecular weight portion.

Various methods are used to control the molecular weight distribution of the polymer.

Firstly, a multistage reactor is used. This method is a method that polymerizes a polymer while sequentially passing through reactors having various polymerization conditions, thereby synthesizing a polymer having a wide molecular weight distribution, which is applied in various processes. However, this method has to go through several reactors, so there are problems in efficiency and economics. The second method is to blend polymers of various molecular weights after polymerization. This method also requires an additional cost after the polymerization, and may have a compatibility problem due to a difference in melt viscosity between blending polymers. The third method is to produce polypropylene having desired properties and molecular weight distribution from the polymerization stage by manipulating the catalyst in a single reactor.

Metallocene catalysts can vary the stereoregularity, melting point, crystallinity, etc. of the polymer finally produced by the change in structure and polymerization conditions. Accordingly, by using various types of metallocene catalysts mixed with Ziegler-Natta catalysts, it is expected that a product having desired properties such as molecular weight distribution and stereoregularity can be produced.

When processing requires an atactic polypropylene moiety, it is possible to control the stereoregularity of the final polymer produced by polymerizing polypropylene using a mixed catalyst system in which a catalyst producing a polymer having no stereoregularity is mixed. When various molecular weight distributions are required, it is thought that the molecular weight distribution can be controlled by mixing a metallocene catalyst and a Ziegler-Natta catalyst which produce polymers of different molecular weights. On the other hand, the difficulty in processing due to the narrow molecular weight distribution of the metallocene catalyst and the improved adaptability to the process of the metallocene catalyst are expected to be improved by mixing with the Ziegler-Natta catalyst.

The methods reported in the literature for the control of molecular weight distribution are intended to improve the molecular weight distribution by manipulating the active site of each catalytic metal component, forming crops of multiple metals by using several metals in the synthesis of side solvents. . However, in this method, the process of preparing the catalyst and the components of the catalyst are complicated, which causes many difficulties in not only analyzing the catalyst but also reproducing it.

Recently, in order to make up the catalyst system which can control the disadvantage of the metallocene catalyst and control the molecular weight distribution, the production of a mixed catalyst system using the metallocene catalyst has been attempted. US Patent No. 4,975,403, US Patent, 4,530,914, Republic of Korea Patent Publication No. 89-5155, etc. has been proposed a method of polymerizing olefins by mixing a heterogeneous metallocene catalyst. US Patent 4,701,432, US Patent 5,183,867, European Patent 436328, Japanese Patent Laid-Open No. 5-255435, etc., a method of simultaneously introducing a Ziegler-Natta active site and a metallocene catalyst from the step of preparing the catalyst, European Patent 585512A1 In the following, a method of introducing a metallocene catalyst to a Ziegler-Natta catalyst is disclosed. However, these methods have difficulty in securing the reproducibility as well as analyzing the catalyst because a new catalyst has to be prepared. Japanese Patent Laid-Open No. 4-85306 discloses a method of modifying a Ziegler-Natta catalyst to a metallocene catalyst, but it is not easy to control molecular weight distribution and properties. U.S. Patent 5,395,810, U.S. Patent 5,242,876, Japanese Patent Application Laid-Open No. 5-255431, European Patent 536104A1, European Patent 436399A2, Korean Patent Publication No. 94-23934, etc. The polymerization of olefins is presented. However, in these patents, only the polymerization by the mixed catalyst of the two catalysts is presented, and there is no specific reference to the selection of polymerization conditions or the selection of organometallic compounds for the control of molecular weight distribution and properties.

The present invention is to solve the problems of the prior art, in the use of Ziegler-Natta and metallocene catalyst to produce a polypropylene having the desired properties and molecular weight distribution, the two catalysts are added sequentially, and the cocatalyst By using an organoaluminum compound or aluminoxane as appropriate, and controlling the properties and molecular weight distribution of the final polypropylene to be polymerized by changing the polymerization time of the catalyst and the like and thereby improving the processability and physical properties The purpose is to provide.

In the present invention, a metallocene catalyst and a Ziegler-Natta catalyst are sequentially added, and an organoaluminum compound or aluminoxane or a mixture thereof is suitably used as a promoter, and polymerization time, external electron donor administration, etc. are controlled. do.

Hereinafter, a method for preparing polypropylene whose molecular weight distribution and properties can be controlled by the sequential addition of the Ziegler-Natta catalyst and the metallocene catalyst according to the present invention will be described in detail.

In the present invention, the term "polymerization" may be used to include not only homopolymerization but also copolymerization, and the term "polymer" may be used to mean not only homopolymer but also copolymer.

In the present invention, polypropylene means a block or irregular copolymer of propylene homopolymer or other α-olefin having 2-18 carbon atoms. Examples of other α-olefins include ethylene, 1-butene, 1-pentene, 1-hexene and 1-octene. The amount of α-olefin copolymerized with propylene is up to 0-50 mol% per mole propylene.

In the present invention, sequential addition refers to temporally or sequentially or in parallel in a single reactor or in one or more serially connected polymerization reactors or in one or more parallelly connected polymerization reactors in which a single or mixed catalyst of Ziegler-Natta catalyst and metallocene catalyst is used. In the case of reactors connected in the same manner, it means that there is a spatial difference in the addition of the catalyst. An example of sequential addition is a method wherein or after the synthesis of polypropylene by the addition of at least one Ziegler-Natta catalyst in time or in sequence prior to the synthesis of polypropylene by the addition of at least one metallocene catalyst. How to do it.

The Ziegler-Natta catalyst system is characterized in that it is formed of a [A] transition metal compound, an [A] organoaluminum compound as a cocatalyst, and an optionally [C] electron donor.

The catalyst component [A] is of the general formula MR ⁺ _X , wherein M is a metal, R is halogen or hydrocarbyloxy and x is the oxidation number of the metal. Preferably M is a group IV B or VB or VI B of the periodic table. A metal belonging to the group, more preferably a metal of group IV B of the periodic table, even more preferably titanium, R is preferably chlorine or bromine or alkoxy or phenoxy and more preferably chlorine or ethoxy, Even more preferred is chlorine.) A mixture of transition metal compounds may be used, in which case the number of transition metal compounds is not limited.

The transition metal compound may or may not be supported. If supported, a chemically inert solid that does not cause chemical reaction with the Ziegler-Natta catalyst and the metallocene catalyst is used as the support.

Cocatalyst component [B] is an organoaluminum compound represented by the formula R _n AlY _3-n , wherein R is a hydrocarbon having 1-20 carbon atoms, Y is halogen, and 0 ≦ _n ≦ ₃ ; or Aluminoxane or mixtures thereof. Specific examples of aluminoxanes include general formula (I) and general formula (II).

A compound represented by the above may be exemplified, and in addition, it may be a ladder structure, a lattice structure, an oxobridged cluster structure, or the like. In such aluminoxane, R is a hydrocarbon such as methyl group, ethyl group, propyl group, butyl group, etc., m is 2 or more, preferably an integer of 5-40.

Said cocatalyst component [B] is not added at the time of preparation of a catalyst, but is added at the time of superposition | polymerization.

The subcatalyst component [C] can be classified into an internal electron donor present in the catalyst as an electron donor and an external electron donor administered together with a promoter during polymerization. The internal electron donor may be added at the time of preparation of the catalyst to exemplify a phthalate-based compound, and specifically, to diisobutyl phthalate, dinormalyl phthalate, dioctyl phthalate, or a mixture thereof.

The external electron donor is specifically represented by the following structural formula (III)

(Wherein R ¹ , R ³ is an alkoxy group such as methoxy, ethoxy, butoxy or an arylalkyl group, R ² is an alkyl group such as methyl, ethyl, butyl or an alkoxy group such as methoxy, ethoxy, butoxy or an arylalkyl group) , R ⁴ is an aromatic group such as phenyl, anthracenyl, naphthalenyl or a cycloaliphatic group such as cyclopentyl, cyclohexyl, cyclooctyl, and X is carbon, silicon, etc. Used. The external electron donor is used in an amount of 0.001-50 mol%, preferably 0.01-20 mol%, more preferably 0.02-10 mol%, per mol of the promoter. If the content is less than 0.001 mol%, the problem of improvement of stereoregularity does not occur, and if it is used more than 50 mol%, it no longer affects stereoregularity.

Meanwhile, the metallocene catalyst system is characterized by being formed of [D] transition metal compound, [E] organoaluminum compound and optionally [F] water as a promoter.

The catalyst component [D] is a transition metal compound, specifically, a compound containing a transition metal selected from the group consisting of titanium, zirconium and hafnium of the Group IV B group of the periodic table, preferably a group having a conjugated? Formula (IV) as transition metal compound

Wherein R ¹ and R ² are cycloalkadienyl or aryl groups, R ³ and R ⁴ are cycloalkadiethyl groups, aryl groups, indenyl groups, fluorel groups, aralalkyl, alkoxy or halogen atoms or hydrogen, and M is The transition metal, X may be a lower alkyl group, an alkenyl group, a chiral group, and Si, S, N, O, P, etc.) or an ionized ionic compound represented by the following formula (V):

^{[C +] [A -]} (Ⅴ)

(Where, [C ^+] is the cation is, [A ^-]. Is an anion) is used.

In the structural formula (IV), examples of the cycloalkadienyl group include cyclopentadienyl group, methylcyclopentadienyl group, ethylcyclopentadienyl group, t-butylcyclopentadienyl group, dimethylcyclopentadienyl group, pentamethylcyclopentadienyl group, and phenyl Ligands such as cyclopentadienyl groups, indenyl groups, tetrahydroindenyl groups, fluorenyl groups or substituted ligands can be exemplified.

Examples of the aryl group include a phenyl group and a tolyl group. Examples of the aryl group include a benzyl group and neophil group. Examples of the alkoxy group include a methoxy group, propoxy group, isopropoxy group and butoxy group. Can be. Examples of the halogen atom include fluorine and chlorine, and lower alkyl groups and alkenyl groups include methyl group, ethyl group, propyl group, isopropyl group, butyl group and ethylene group. Dimethyl silicone group etc. can be illustrated.

In addition, as the anion in the formula _{(Ⅴ) [B (C 6} F 5) 4] - and the like can be given ^{_{-, [B (C 6 H}} 5) 4].

However, each component is not limited to this example.

The transition metal compound may or may not be supported. In the case of the supporting metal compound, a chemically inert solid which does not cause a chemical reaction with a Ziegler-Natta catalyst or a metallocene catalyst should be used.

The cocatalyst component [E] is an organoaluminum compound, which has the same structure as the catalyst component [B] in the Ziegler-Natta catalyst, and is also administered during the polymerization of propylene. The catalyst component [F] is water, and the foreign substance is water contained in a compound or salts used when preparing the catalyst component [E] or water dissolved in a polymerization solvent.

Polypropylene in the present invention is prepared by a method of polymerization by sequentially adding a single or a mixture of Ziegler-Natta catalyst and metallocene catalyst. When the catalysts are added sequentially, the properties of polypropylene are changed as the polymerization time of each catalyst is changed. As the polymerization time by the metallocene catalyst is longer, the catalytic activity increases, but the stereoregularity and molecular weight of polypropylene are However, the longer the polymerization time by the Ziegler-Natta catalyst, the lower the activity, but the stereoregularity and molecular weight increases.

When producing propylene by the above method, the polymerization reaction can be carried out in gas phase, liquid phase or solution phase. When performing a polymerization reaction in a liquid phase, a hydrocarbon solvent may be used and olefin itself may be used as a solvent. Hydrocarbons used as solvents include aliphatic hydrocarbons such as butane, isobutane, pentane, hexane, heptane, octane, nonane, decane, dodecane, hexadecane and octadecane, cyclopentane, methylcyclopentane, cyclohexane and cyclooctane Alicyclic hydrocarbons, such as alicyclic hydrocarbons, such as benzene, toluene, and xylene, and petroleum components, such as gasoline, kerosene, and diesel, are mentioned. The external electron donor may or may not be added, and the stereoregularity increases when the external electron donor is added.

In addition, the molecular weight and molecular weight distribution of the polypropylene can be controlled by adding or not adding hydrogen during the polymerization of polypropylene, while the molecular weight decreases while hydrogen is added, whereas the value of the molecular weight distribution is reduced. Becomes high.

On the other hand, polymerization temperature is -50-350 degreeC normally, Preferably it is the range of 0-310 degreeC. If it is below -50 ° C, the polymerization activity is not good, and if it exceeds 350 ° C, the stereoregularity is poor, which is not good. The polymerization pressure is usually at -250 kg / cm 2 at atmospheric pressure, preferably at -200 kg / cm 2 at atmospheric pressure, and if it exceeds 250 kg / cm 2, it is not preferable from an industrial and economical point of view. The polymerization reaction can be carried out by any of batch, semicontinuous and continuous methods.

In addition, during the polypropylene polymerization, heat stabilizers, light stabilizers, flame retardants, carbon blacks, pigments, antioxidants, and the like, which are commonly added, may be added. Furthermore, polypropylene having various properties and molecular weight distributions according to the present invention can be mixed with low density polyethylene (LDPE), high density polyethylene (HDPE), polypropylene, polybutene, EP (ethylene / propylene) rubber, and the like.

Hereinafter, although an Example demonstrates this invention, this invention is not limited by these Examples.

In the following examples, thermal properties, regularity, molecular weight, molecular weight distribution, etc. were measured by the following method.

(1) thermal properties

Thermal properties such as melting point (T _m ), low temperature crystallization temperature (T _mc ), and glass transition temperature (T _g ) of polymers were investigated by differential scanning calorimetry (DSC), and the instrument was DSC 7 of Perkin Elimer. Was used. The sample was weighed to 5.5 ± 0.5mg and placed in an aluminum pan, and then subjected to the first irradiation at a temperature rising rate of 20 ° C / min from 50 ° C to 200 ° C under a nitrogen stream of 1.2 kg / cm 2, and then to 20 ° C to 50 ° C. T _mc was measured while cooling at a rate of / min. T _m and heat of fusion (ΔII _m ) were measured while performing secondary irradiation at a temperature increase rate of 20 ° C./min to 50 ° C.-200 ° C. The temperature and the heat of fusion were corrected by the standard method using high purity indium. T _g of the polypropylene was investigated after rapidly cooled to -60 ℃ ℃ at a rate of 100 / min after the first temperature increase, while temperature was raised again at a rate of 20 ℃ / min. The crystallinity of polypropylene was calculated by dividing the heat of fusion of each polymer by 188 J / g, the standard heat of fusion.

(2) I.I: Isotacticity Index

Stereoregularity of polypropylene was performed with the isotacticity index (I. I.), an amount insoluble in boiling heptane. The polymer was previously treated with a heat stabilizer to prevent degradation during analysis. A certain amount of the completely dried polymer was quantitatively placed in a timing filter and extracted with heptane in a Soxhlet type extraction apparatus. The extraction time was fixed at 5 hours, and the remaining polymer after extraction was collected, dried in vacuo at 80 ° C, quantitatively weighed and weighed. It was.

(3) Molecular weight and molecular weight distribution

The molecular weight and molecular weight distribution of the polymer were determined using gel permeation chromatography (GPC). GPC used PL-210 GPC of Polymer Laboratory Co., Ltd. and was measured by RI detector using 1,2,4-trichlorobenzene (1,2,4-trichlorobenzene) as solvent at 160 ° C. The calibration curve obtained from polystyrene with narrow molecular weight distribution was corrected with a standard polyethylene sample to obtain a molecular weight calibration curve. The number average molecular weight (M _n ), weight average molecular weight (M _W ) and molecular weight distribution (M _W / M _n ) and the like.

Production Example

* Ziegler-Natta catalyst manufacture

Under a nitrogen atmosphere, a certain amount of toluene and 100 zirconia beads 3 mm in diameter were added to a 200 ml stainless steel container. Miso dichloride, titanium tetrachloride, and diisobutyl phthalate and dioctyl phthalate were added to the internal electron donor, followed by ball-milling at room temperature for 72 hours. The Ziegler-Natta catalyst thus formed was washed five times with toluene and then sprayed into a predetermined amount of toluene. The catalyst thus prepared was named MgCl ₂ -Ti catalyst. The content of Ti in the supported catalyst was 1.10 wt%.

* Preparation of Metallocene Catalyst

Aldrich's rac-ethylenebis (indenyl) zirconium (4) dichloride catalyst, ie rac-Et (Ind) ₂ ZrCl ₂ (EIZ) catalyst, was used.

Example 1

The polymerization of propylene was carried out at atmospheric pressure using a vitreous reactor. The reactor was decompressed to a vacuum of 3 torr or less and charged with nitrogen of high purity five times. After adjusting the temperature of the reactor to 40 ° C. constantly, 200 ml of toluene as a solvent was quantified by a syringe while nitrogen was blown to prevent backflow of air. When the temperature is kept constant, the gas unit (propylene unit) is flowed in the solvent until it is saturated while checking with a flow controller, and then the EIZ catalyst and Ziegler, which are metallocene catalysts having polymerization conditions and metal contents as shown in Table 1 below. MgCl ₂ -Ti catalyst, which is a Nata catalyst, was sequentially added, and aluminoxane was added as a cocatalyst to polymerize propylene. First, an EIZ catalyst was added and 10 minutes later, a MgCl ₂ -Ti catalyst was added to polymerize. After the polymerization was carried out for one time with one catalyst, another catalyst was added, and the polymerization was performed for the remaining time, and the total polymerization time was 1 hour. The polymerization was terminated by injecting 10 ml of ethanol. The reaction product was stirred for about 24 hours in about 5% by weight HCl- methanol and then again for 24 hours in clean methanol. Subsequently, the resultant was filtered through a filter paper and vacuum dried at about 80 ° C. for at least 24 hours to obtain a final polymerization product. The value of the overall activity of the catalyst was determined in units of kg polymer / (mol metal mol-monomer · h) from the weight of the final product.

Physical property measurement results are shown in Table 1 below.

Comparative Example 1

The Ziegler-Natta catalyst or the metallocene catalyst was carried out in the same manner as in Example 1 except that each was used alone according to the polymerization conditions shown in Table 1 below. When using a Ziegler-Natta catalyst or a metallocene catalyst alone, the same aluminoxane as in Example 1 was also used as a promoter. Physical property measurement results are shown in Table 1 below.

As a result of the experiment, Example 1 had two melting points compared to Comparative Example 1, and the catalytic activity was about the middle value of using the Ziegler-Natta catalyst and the metallocene catalyst, respectively.

Example 2

Next, the Ziegler-Natta catalyst and the metallocene catalyst having the same contents as in Table 2 are administered in the order shown in Table 2, and triethylaluminum is used to polymerize with the Ziegler-Natta catalyst, and aluminoxane is polymerized with the metallocene catalyst. It carried out similarly to Example 1 except having superposed | polymerized using it as a promoter. The total polymerization time was similarly 1 hour, and the measurement results of the physical properties are shown in Table 2 below.

Comparative Example 2

The same process as in Example 2 was carried out except that the Ziegler-Natta catalyst and the metallocene catalyst were sequentially added to each other without polymerization. When the polymerization was carried out alone using a Ziegler-Natta catalyst, the polymerization was carried out using triethylaluminum as a cocatalyst and aluminoxane as a cocatalyst when polymerizing alone with a metallocene catalyst. 2 is shown.

Example 2 had two melting points compared to Comparative Example 2, and the catalytic activity was about the middle value of each of the Ziegler-Natta and metallocene catalysts. The molecular weight also showed a moderate value, but the molecular weight distribution was increased in each case. As the polymerization time of each catalyst was changed, it was possible to control the polyffh propylene. As the polymerization time of the metallocene catalyst was increased, the stereoregularity and molecular weight of the polyffh propylene decreased, and the Ziegler-Natta catalyst As the polymerization time was longer, the stereoregularity and molecular weight increased.

Example 3

As in Example 2, the polymerization was carried out using triethylaluminum as a co-catalyst when polymerizing with a Ziegler-Natta catalyst and aluminoxane as a co-catalyst when polymerizing with a metallocene catalyst. Nin cyclohexyldimethoxymethylsilane was administered by 0.2 times the amount of triethylaluminum. The total polymerization time was similarly 1 hour, and the measurement results of the physical properties are shown in Table 3 below.

Comparative Example 3

Except for polymerization using only Ziegler-Natta catalyst alone, it was carried out in the same manner as in Example 3, the physical properties are shown in Table 3 below.

As a result of the experiment, when the external electron donor was added as in Example 3, it was found that the stereoregularity was increased as compared with Example 2 which was not added.

Example 4

The same procedure as in Example 2 was carried out except that the hydrogen partial pressure was pre-mixed with a predetermined proportion of hydrogen and gas units in a mixing chamber so as to be 0.27 atm. The concentration of the monomer dissolved in the rudwoo solvent of the hydrogenated polymerization was calculated in terms of the partial pressure of ethylene, and the physical property measurement results are shown in Table 4 below.

[Comparative Example 4]

The Ziegler-Natta catalyst or the metallocene catalyst was added in the same manner as in Example 4 except that the polymerization was carried out using a single catalyst instead of the polymerization. The measurement results of the physical properties are shown in Table 4 below.

In the case of Example 4 in which hydrogen was added, the molecular weight was lower than that in Example 2 in which hydrogen was not added, and the value of the molecular weight distribution was higher than in the case where no hydrogen was added.

[Table 1] Polymerization Characteristics of Propylene and Properties of Polyffhylene Obtained by Sequential Addition of MgCl ₂ -Ti Catalyst after EIZ Catalyst Addition

Promoter: Aluminoxane (MAO)

^a : Activity unit: kg PP / mol-Zrmol-propylene

^b Amount remaining undissolved in boiling heptane (% by weight)

^c MgCl ₂ -Ti catalyst was added 10 minutes after EIZ catalyst

Polymerization condition: When sequential addition of catalyst → [Ti + Zr] = 2.81 × 10 ^-5 mol / L, cocatalyst = MAO ([Al] / [Metal] = 4000), 40 ° C, 1 atm, 1 h

EIZ catalyst alone → Zr = 3.19 × 10 ^-5 mol / L, Cocatalyst = MAO ([Al] / [Metal] = 4000), 40 ° C, 1 atm, 1 h

MgCl ₂ -Ti catalyst alone → [Ti] = 2.81 × 10 ^-5 mol / L, cocatalyst = MAO ([Al] / [Metal] = 4000), 40 ° C, 1 atm, 1 h

[Table 2] Polymerization Characteristics of Polypropylene and Properties of Polypropylene Obtained by Sequential Addition of MgCl ₂ -Ti Catalyst after EIZ Catalyst Addition

Cocatalyst: triethylaluminum (TEA), aluminoxane (MAO)

^a : Activity unit: kg PP / mol-Zrmol-propylene

^b Amount remaining undissolved in boiling heptane (% by weight)

Polymerization condition: When sequential addition of catalyst → [Zr] = 6.06 × 10 ^-6 mol / L, [Ti] = 1.52 × 10 ^-4 mol / L,

Promoter: MAO ([Al] / [Zr] = 4000) and TEA ([Al] / [Ti] = 100), 40 ° C., 1 atm, 1 h

EIZ catalyst alone → Zr = 3.19 × 10 ^-5 mol / L, Cocatalyst = MAO ([Al] / [Zr] = 4000), 40 ° C, 1 atm, 1 h

MgCl ₂ -Ti catalyst alone → [Ti] = 1.52 × 10 ^-4 mol / L, Promoter = TEA ([Al] / [Ti] = 100), 40 ° C, 1 atm, 1 h

[Table 3] Polymerization Properties and Properties of Polypropylene Obtained by Sequential Addition of EIZ / MAO Catalyst in the State of External Electron Donor ^a to MgCl ₂ -Ti Catalyst

Cocatalyst: triethylaluminum (TEA), aluminoxane (MAO)

^a external electron donor: cyclohexyl methyl dimethoxy silane (CHDMS)

Activity Unit: kg PP / mol-Zrmol-propylene

^b Amount remaining undissolved in boiling heptane (% by weight)

Polymerization condition: Sequential addition of catalyst → [Zr] = 6.06 × 10 ^-6 mol / L, [Ti] = 1.52 × 10 ^-4 mol / L, external electron donor = ([CHDMS] / [Al] = 0.2) ,

Promoter: MAO ([Al] / [Zr] = 4000) and TEA ([Al] / [Ti] = 100), 40 ° C., 1 atm, 1 h

MgCl ₂ -Ti catalyst alone → [Ti] = 1.52 × 10 ^-4 mol / L, external electron donor = ([CHDMS] / [Al] = 0.2),

Promoter = TEA ([Al] / [Ti] = 100), 40 ° C., 1 atm, 1 h

[Table 4] Polymerization Properties of Propylene and Properties of Polypropylene Obtained by Sequential Addition of MgCl ₂ -Ti Catalyst after ^a EIZ Catalyst Addition in the Presence of Hydrogen Gas

Cocatalyst: triethylaluminum (TEA), aluminoxane (MAO)

^a partial hydrogen = 0.27 atm.

^b Activity Unit: kg PP / mol-Zrmol-propylene

^b Amount remaining undissolved in boiling heptane (% by weight)

Polymerization condition: When sequential addition of catalyst → [Zr] = 6.06 × 10 ^-6 mol / L, [Ti] = 1.52 × 10 ^-4 mol / L,

Promoter: MAO ([Al] / [Zr] = 4000) and TEA ([Al] / [Ti] = 100), 40 ° C., 1 atm, 1 h

EIZ catalyst alone → Zr = 3.19 × 10 ^-5 mol / L, Cocatalyst = MAO ([Al] / [Zr] = 4000), 40 ° C, 1 atm, 1 h

MgCl ₂ -Ti catalyst alone → [Ti] = 1.52 × 10 ^-4 mol / L, Promoter = TEA ([Al] / [Ti] = 100), 40 ° C, 1 atm, 1 h

As in the present invention, a Ziegler-Natta catalyst and a metallocene catalyst are sequentially added, and the polypropylene polymerized and manufactured using an organoaluminum compound or aluminoxane as a cocatalyst has various properties and molecular weight distribution.

In addition, in the present invention, the stereoregularity may be increased by adding an external electron donor, or the molecular weight may be reduced by adding hydrogen, and the stereoregularity and molecular weight may be controlled by controlling the polymerization time by the catalyst.

Polypropylene may be used to form a variety of products, such as plates, films, containers, fibers.

Claims (4)

In preparing a polypropylene having various molecular weights, molecular weight distribution, melting point and stereoregularity by polymerization, a metallocene catalyst and a Ziegler-Natta catalyst are added sequentially, and as a cocatalyst of the Ziegler-Natta catalyst, a general formula R _n 1 or a mixture thereof selected from organoaluminum compounds or aluminoxanes represented by AlY _3-n , wherein R is a hydrocarbon having 1-20 carbon atoms, Y is halogen, and 0≤n≤3 Aluminoxane is used as a cocatalyst of a metallocene catalyst, The manufacturing method of the polypropylene characterized by the above-mentioned. The method of claim 1, wherein an external electron donor is added during polymerization to increase stereoregularity. The method for producing polypropylene according to claim 1, wherein the polymerization decreases the molecular weight by increasing hydrogen and increases the value of the molecular weight distribution. The polypropylene produced is a homopolymer of propylene or an irregular copolymer of propylene with an alpha -olefin having 2 to 18 carbon atoms or a block copolymer of propylene with an alpha -olefin having 2 to 18 carbon atoms. Method for producing a polypropylene, characterized in that.