KR20120111530A - Method for preparing polyolefin and polyolefin therefrom - Google Patents

Abstract

PURPOSE: A manufacturing method of polyolefin is provided to able to provide polyolefin which is especially suitable for blow molding because of low polymer melt index(MI), high polydispersity(PDI) and high full notch creep test to density or polymer melt index. CONSTITUTION: A manufacturing method of polyolefin comprises a step of polymerizing olefin under the presence of a metallocene catalyst and a molecular weight controller. The polymerization is conducted in a cascade-CSTR reactor. The cascade-CSTR reactor comprises a first reactor, a second reactor and a post reactor. Polyolefin is manufactured by the manufacturing method, has multi-modal molecular weight distribution, and has weight average molecular weight of 100,000-700,000. [Reference numerals] (AA) First reactor; (BB) Second reactor; (CC) Post reactor

Description

Method for preparing polyolefin and polyolefin made therefrom {Method For Preparing Polyolefin And Polyolefin Therefrom}

The present invention relates to a method for producing polyolefin and a polyolefin prepared therefrom. More specifically, the polymer melt index MI (5 kg basis) is low, polydispersity PDI is high, and the density is higher than that of general blow molding polyolefin. The present invention relates to a method for producing a polyolefin, which is particularly suitable for blow molding molding due to a high stress notch creep test (FNCT) compared to a polymer melt index.

Metallocene catalysts using Group 4 transition metals have excellent catalytic activity and are easy to control the molecular weight and the degree of dispersion thereof compared to the existing Ziegler-Natta catalysts and are used in various organic reactions and polymer reactions.

In general, polymers polymerized with a metallocene catalyst have a narrow molecular weight distribution and a uniform distribution of comonomers, resulting in better mechanical properties and transparency and less solvent extraction than polymers polymerized with a Ziegler-Natta catalyst. Due to the molecular weight distribution, there is a problem in that workability is greatly reduced.

In general, the wider the molecular weight distribution, the greater the degree of viscosity decrease according to the shear rate, which shows excellent processability in the processing area. Polymers polymerized with metallocene catalysts, especially polyethylene, have high viscosity at high shear rates, which causes However, the pressure is excessively high, the extrusion productivity is reduced, the bubble stability during blow molding processing is greatly reduced, the surface of the manufactured blow molded molded article is uneven, resulting in a decrease in transparency.

Therefore, there is an urgent need to develop a method for producing a polyolefin having excellent mechanical properties using a metallocene catalyst and having greatly improved processability.

In order to solve the problems of the prior art as described above, the present invention has a low polymer melt index MI (5 kg basis), a polydispersity PDI is high, and a stress resistance compared to a density or polymer melt index as compared to a general blow molding polyolefin. It is an object of the present invention to provide a method for producing a polyolefin which is particularly suitable for blow molding molding due to its high notch creep test (FNCT).

The above and other objects of the present invention can be achieved by the present invention described below.

In order to achieve the above object, the present invention provides a method for producing a polyolefin characterized in that the olefin is polymerized under a metallocene catalyst and a chain propagation agent (CPA) and a polyolefin prepared therefrom.

As described above, according to the present invention, the polymer melt index MI (5 kg basis) is low, the polydispersity PDI is high, and the stress crack resistance (Full) is higher than the density or polymer melt index, compared to the general blow molding polyolefin. Notch Creep Test (FNCT) has a high effect of providing a method for producing a polyolefin particularly suitable for blow molding molding.

1 is a process diagram schematically showing a specific example of the polyolefin production method of the present invention.
Figure 2 is a graph showing the molecular weight distribution of the polyethylene prepared in Example 1 and Comparative Example 1.

Hereinafter, the present invention will be described in detail.

The polyolefin production method of the present invention is characterized in that the olefin is polymerized under a metallocene catalyst and a chain propagation agent (CPA).

The polymerization is preferably carried out in a Cascade-CSTR Reactor.

The multi-stage-CSTR reactor preferably comprises a first reactor, a second reactor and a post reactor.

Preferably, the metallocene catalyst and the olefin are introduced into the first reactor, and the molecular weight regulator is introduced into the second reactor.

The temperature of the second reactor is preferably from +20 ℃ to -40 ℃, more preferably from +10 ℃ to -30 ℃, more preferably from +0 ℃ to-than the temperature of the first reactor It is 20 ℃, within this range it is easy to transfer the slurry from the first reactor to the second reactor and the molecular weight of the polyolefin produced in the second reactor is easy.

The pressure of the second reactor is preferably +1 to -5 bar, more preferably +0.5 to -4 bar, and most preferably +0 to -3 bar compared to the pressure of the first reactor. In this range, it is easy to transfer the slurry from the first reactor to the second reactor and there is an effect of minimizing the decrease in reaction activity due to the pressure drop.

It is preferable that the olefin and another α-olefin are further added to the second reactor as a comonomer.

The α-olefins are propylene, 1-butene, 1-hexene, 1-octene, 1-pentene, 4-methyl-1-pentene, 1-hexene, 1-heptene, 1-decene, 1-undecene, 1- Dodecene, 1-tetradecene, 1-hexadecene, 1-ikocene, norbornene, norbonadiene, ethylidenenorbornene, vinylnorbornene, dcclopentadiene, 1,4-butadiene, 1,5-penta At least one selected from the group consisting of dienes, 1,6-hexadiene, styrene, alpha-methylstyrene, divinylbenzene, 3-chloromethylstyrene, and the like is preferable, more preferably 1-butene, 1-hexene, 1-octene or a mixture thereof, in this case has an excellent stress cracking resistance.

The α-olefin is 0.01 to 30 parts by weight, preferably 0.1 to 5 parts by weight based on 100 parts by weight of the total olefins, and has excellent stress cracking resistance within a density range suitable for blow molding products within this range. There is.

The polymerization is preferably carried out by further including an alkyl aluminum compound, and generally is not particularly limited in the case of an alkyl aluminum compound that can be used as a promoter for a metallocene catalyst.

The olefins are ethylene, propylene, 1-butene, 1-hexene, 1-octene, 1-pentene, 4-methyl-1-pentene, 1-hexene, 1-heptene, 1-decene, 1-undecene, 1- It may be at least one selected from the group consisting of dodecene, norbornene, ethylidenenorbornene, styrene, alpha-methylstyrene, 3-chloromethylstyrene, and the like, and preferably ethylene.

The metallocene catalyst is preferably a hybrid supported metallocene catalyst including a first metallocene compound, a second metallocene compound, and a carrier.

Preferably, the hybrid supported metallocene catalyst further includes an alkylaluminoxane, a borate compound, or the like. In this case, the activity of the produced polyolefin is improved and the molecular weight distribution is uniform.

The first and second metallocene compounds preferably have a cyclopentadiene skeleton, and more preferably, have a structure in which an alkyl, aryl, amide or alkoxide group is linked to the cyclopentadiene. Excellent effect.

The molecular weight modifier is preferably an organometallic complex, more preferably an organometallic complex, most preferably a cyclopentadienyl metal compound represented by the following Chemical Formula 1 and the following Chemical Formula 2. It is an organometallic complex prepared by reacting the organoaluminum compound to be displayed. In this case, the polymer melt index is lowered, the molecular weight and polydispersity are increased, and the stress cracking resistance is higher than the density or polymer melt index.

[Formula 1]

C _p ¹ C _p ² MX ₂

The C _p ¹ and C _p ² are independently a cyclopentadienyl group, indenyl group, fluorenyl group or derivatives thereof, M is a Group IV element on the periodic table, and X is a halogen element.

The group IV element is preferably titanium, zirconium or hafnium.

Specific examples of the cyclopentadienyl metal compound include biscyclopentadienyl titanium dichloride, biscyclopentadienyl zirconium dichloride, biscyclopentadienyl hafnium dichloride, bisindenitanium dichloride, and bisfluorenyl titanium dichloride. At least one selected from the group consisting of chlorides and the like is preferable.

[Formula 2]

R ₁ R ₂ R ₃ Al

The R ₁ , R ₂ or R ₃ may be independently a C ₁ ~ C ₂₀ alkyl substituent or halogen, it may include a hetero element such as nitrogen or oxygen.

The organoaluminum compound is trimethyl aluminum, triethyl aluminum, tripropyl aluminum, triisopropyl aluminum, triisobutyl aluminum, trihexyl aluminum, trioctyl aluminum, dimethylaluminum chloride, diethylaluminum chloride, dipropylaluminum chloride, diiso It is preferably at least one member selected from the group consisting of butylaluminum chloride, dihexylaluminum chloride, dimethylaluminum dichloride, ethylaluminum dichloride, propylaluminum dichloride, isobutylaluminum dichloride, ethylaluminum sesquichloride and the like.

It is preferable that the molar ratio (M / Al) of the said cyclopentadienyl metal compound (M) and an organoaluminum compound (Al) is 1: 0.1-1: 100.

The molecular weight modifier is preferably 10 ^-7 to 10 ^-1 parts by weight, more preferably 10 ^-5 to 10 ^-2 parts by weight, based on 100 parts by weight of the total olefins, the polymer melt index is low in this range, Polydispersity is high, and stress cracking resistance is greatly improved compared to the density or polymer melt index.

In addition, the molecular weight modifier may be added in an amount of 0.001 to 1000 μmol of M in the organometallic complex based on 1 kg of the olefin (amount charged into the entire reactor), preferably 0.01 to 100 μmol. It is to be added, more preferably in an amount of 0.1 to 50 μmol, most preferably in an amount of 1 to 20 μmol, the polymer melt index is low, polydispersity within this range, In addition, the stress cracking resistance is significantly improved compared to the density and the polymer melt index.

The polyolefin of the present invention is characterized in that it is prepared according to the production method of the polyolefin.

It is preferable that the polyolefin has a bimodal or polymodal molecular weight distribution.

The polyolefin preferably has a weight average molecular weight of 100,000 to 700,000, more preferably 150,000 to 350,000, most preferably 200,000 to 250,000, and has an effect of excellent workability in the processing region within this range.

The polyolefin is preferably used for blow molding, in which case it can satisfy all the physical properties suitable for blow molding.

The polyolefin may be used for films, pipes, bottle caps, and the like.

The hollow molded article of the present invention is characterized in that it comprises the polyolefin.

It will be apparent to those skilled in the art that various modifications and variations can be made in the present invention without departing from the spirit or scope of the present invention. Such variations and modifications are intended to be within the scope of the appended claims.

[Example]

Production Example 1 ((t-Bu-O- (CH ₂ ) ₆ -C ₅ H ₄ ] ₂ ZrCl ₂ Synthesis)

6-Chlorohexanol was used to prepare t-Butyl-O- (CH ₂ ) ₆ -Cl using the method presented in Tetrahedron Lett. 2951 (1988), wherein NaC ₅ H ₅ Was reacted to obtain t-Butyl-O- (CH ₂ ) ₆ -C ₅ H ₅ (yield 60%, bp 80 ° C./0.1 mmHg).

2.0 g (9.0 mmol) of t-Butyl-O- (CH ₂ ) ₆ -C ₅ H ₅ was dissolved in THF at -78 ° C, and 1.0 equivalent of normal butyllithium (n-BuLi) was slowly added thereto, followed by room temperature. The reaction mixture was heated to 8 hours and then reacted for 8 hours. The reaction solution was slowly added to a suspension solution of ZrCl ₄ (THF) ₂ (1.70 g, 4.50 mmol) / THF (30 mL) at −78 ° C., followed by further reaction at room temperature for 6 hours to give a final The reaction product was obtained.

The reaction product was dried in vacuo to remove all volatiles, and then hexane was added to the remaining oily liquid and then filtered using a Schlenk glass filter. The filtered solution was dried in vacuo to remove hexane, and then hexane was added thereto to induce precipitation at low temperature (-20 ° C). The precipitate obtained was filtered at low temperature to give a white solid [t-Bu-O- (CH ₂ ) ₆ -C ₅ H ₄ ] ₂ ZrCl ₂ compound in a yield of 92%. The measured 1H NMR and 13C NMR data of [t-Bu-O- (CH ₂ ) ₆ -C ₅ H ₄ ] ₂ ZrCl _{2 obtained} were as follows.

1 H NMR (300 MHz, CDCl ₃ ): 6.28 (t, J = 2.6 Hz, 2H), 6.19 (t, J = 2.6 Hz, 2H), 3.31 (t, J = 6.6 Hz, 2H), 2.62 (t, J = 8 Hz, 2H), 1.7-1.3 (m, 8H), 1.17 (s, 9H).

13 C NMR (CDCl ₃ ): 135.09, 116.66, 112.28, 72.42, 61.52, 30.66, 30.61, 30.14, 29.18, 27.58, 26.00.

Production Example 2 ([methyl (6-t-buthoxyhexyl) silyl (η5-tetramethylCp) (t-Butylamido)] TiCl ₂ Synthesis)

50 g of Mg was added to a 10 L reactor at room temperature, and then 300 mL of THF was added thereto. After 0.5 g of I ₂ was added thereto, the reactor temperature was maintained at 50 ° C.

After the reactor temperature is stabilized, 250 g of 6-t-butoxyhexyl chloride is added to the reactor at a rate of 5 mL / min using a feeding pump and stirred for 12 hours. (6-t-butoxyhexyl chloride was added to the reactor temperature is increased by about 4 ~ 5 ℃), 6-t-butoxyhexyl magnesium chloride (6-t-buthoxyhexyl magnesium chloride) was prepared.

The 6-t-butoxyhexyl magnesium chloride was obtained as a black reaction solution. 2 mL of the black reaction solution was taken and water was added to obtain an organic layer, and the compound included in the organic layer was subjected to 1H-NMR. It was confirmed that the result of the Grignard reaction 6-t-butoxyhexane (6-t-buthoxyhexane).

500 g of MeSiCl ₃ and 1 L of THF were added to a separate reactor, and the reactor temperature was cooled to -20 ° C. Into this reactor, 560 g of 6-t-butoxyhexyl magnesium chloride prepared above was introduced at a rate of 5 mL / min using an infusion pump, and then stirred for 12 hours while slowly raising the temperature of the reactor to room temperature.

After 12 hours of stirring, it was confirmed that white MgCl ₂ salt was formed, and 4 L of hexane was added thereto, followed by removing the salt through a laboratory pressure dehydration filtration apparatus (labdori, Han River Engineering Co., Ltd.) to obtain a filtered solution. there was.

The filtered solution was added to the reactor and hexane was removed at 70 ° C. to obtain a pale yellow liquid, which was confirmed to be a methyl (6-t-butoxyhexyl) dichlorosilane compound through 1H NMR (1H NMR (CDCl 3): 3.3 (t, 2H), 1.5 (m, 3H), 1.3 (m, 5H), 1.2 (s, 9H), 1.1 (m, 2H), 0.7 (s, 3H)).

1.2 mol (150 g) of tetramethylcyclopentadiene and 2.4 L of THF were added to a separate reactor, and the reactor temperature was cooled to -20 ° C. Then, 480 mL of 2.5M concentration of n-BuLi was injected using an infusion pump to 5 mL / min. Was added at the rate of. After the addition of n-BuLi, the reactor was slowly stirred for 12 hours while slowly raising the temperature to room temperature, and then 326 g (350 mL) of methyl (6-t-butoxyhexyl) dichlorosilane was rapidly reacted. After stirring for 12 hours while slowly raising the temperature of the reactor to room temperature, the reactor temperature was cooled to 0 ° C and 2 equivalents of t-BuNH ₂ was added thereto.

After stirring the reactor temperature slowly to room temperature for 12 hours, THF was removed, 4 L of hexane was added, and salt was removed through an experimental pressure dehydration filtration apparatus (labdori, Han River Engineering Co., Ltd.) to filter the solution. Could get After the filtered solution was added to the reactor again, hexane was removed at 70 ° C. to obtain a yellow solution, which was identified as methyl (6-t-buthoxyhexyl) (tetramethylCpH) t-Butylaminosilane through 1H NMR.

10 mmol of TiCl ₃ (THF) ₃ was quickly added to a dilithium salt solution formed by reacting Methyl (6-t-buthoxyhexyl) (tetramethylCpH) t-Butylaminosilane with n-BuLi under -78 ° C and THF, and then slowly -78 It stirred for 12 hours, heating up at room temperature. After stirring for 12 hours, 10 mmol of equivalent PbCl ₂ was added to the reaction solution at room temperature, followed by stirring for 12 hours to obtain a dark black solution.

After removing THF from the dark black solution, hexane was added and then filtered to obtain a filtered solution. Remove the hexane from the filter solution and confirm that the remaining material is [methyl (6-t-buthoxyhexyl) silyl (η5-tetramethylCp) (t-Butylamido)] TiCl _{2 through} 1H NMR (1H NMR (CDCl ₃ ): 3.3 ( s, 4H), 2.2 (s, 6H), 2.1 (s, 6H), 1.8 to 0.8 (m), 1.4 (s, 9H), 1.2 (s, 9H), 0.7 (s, 3H)) It was.

Preparation Example 3 (Preparation of Supported Metallocene Catalyst)

30 ml of toluene was added to 3 g of calcined silica (Sylopol 2212, Grace Davison) having a pore volume of 1.47 ml / g at a surface area of 280 m ² / g, and then [t-Bu-O prepared in Preparation Example 1 at 70 ° C. 0.36 mmole of-(CH ₂ ) ₆ -C ₅ H ₄ ] ₂ ZrCl ₂ was added and reacted for 1 hour, and then the remaining solid was washed with toluene. The solid component was reacted with 15 ml (10 wt% Toluene solution) of methylaluminoxane (MAO) at 70 ° C. for 2 hours, washed with toluene to remove the unreacted MAO solution, and a solid component containing methylaluminoxane was prepared.

The total amount of the solid component containing methylaluminoxane and [methyl (6-t-buthoxyhexyl) silyl (η5-tetramethylCp) (t-Butylamido)] TiCl ₂ 0.36mmole prepared in Preparation Example 2 were used in a solvent of toluene at 50 ° C. After reacting with toluene for 1 hour and washing with toluene, the washed solid component and trityl tetrakis (penta-fluoro-phenyl) borate (TB) 1.2mmole was reacted with toluene as a solvent for 1 hour at 50 ℃, 50 It dried under reduced pressure at ° C to prepare a metallocene supported catalyst in a solid state. At this time, the molar ratio of boron (B) / transition metal (Zr) was 1.3.

Production Example 4 (Preparation of Molecular Weight Control Agent)

Bis (cyclopentadienyl) titanium dichloride 1.25g and toluene 10ml were sequentially added to a 250ml round bottom flask, followed by stirring. 10 ml of triisooctylaluminum (1M in hexane) was added thereto, stirred at room temperature for 3 days, and then the solvent was removed in vacuo to give a green mixture. As the green mixture was produced, it was found that the titanocene was reduced to + trivalent, and the green mixture was not oxidized or changed in color. In the following the green mixture was used as it is without purification. In addition, H NMR confirmed that it was a mixture of bis (cyclopentadienyl) octyl titanium and dioctylaluminum chloride (1H NMR (CDCl ₃ , 500MHz): 7.31 (br s, 10H), 2.43 (d, 4H), 1.95 ~ 1.2 ( m, 28H), 1.2-0.9 (m, 19H)).

Example 1

A multistage continuous CSTR reactor (see FIG. 1 below) consisting of two 0.2 m ³ capacity reactors was used.

Into the first reactor, 35 kg / hr of hexane, 10 kg / hr of ethylene, 1.5 g / hr of hydrogen, and triethylaluminum (TEAL) were injected at a flow rate of 40 mmol / hr, respectively. The supported catalyst was injected at 1 g / hr (180 μmol / hr). In this case, the first reactor was maintained at 84 ° C., the pressure was maintained at 9 bar, the residence time of the reactants was maintained at 2.5 hours, and the slurry mixture containing the polymer was continuously transferred to the second reactor while maintaining a constant liquid level in the reactor. It was made.

Hexane 21 kg / hr, ethylene 6.5 kg / hr, 1- hexene 70 g / hr, triethylaluminum (TEAL) is injected into the second reactor at a flow rate of 20 mmol / hr, the molecular weight regulator prepared in Preparation Example 4 Injected at 80 μmol / hr. The second reactor was maintained at 80 ° C., the pressure was maintained at 7 bar, the residence time of the reactants was maintained at 1.5 hours, and the polymer mixture was continuously passed to the post reactor while maintaining a constant liquid level in the reactor. .

The post reactor was maintained at 78 ° C. and unreacted monomers were polymerized. The polymerization product was then made into final polyethylene via a solvent removal plant and a dryer. The polyethylene produced was mixed with 1000 ppm of calcium stearate (manufactured by Dubon Industries) and 2000 ppm of heat stabilizer 21B (manufactured by Songwon Industries), and then made into pellets.

Example 2

Instead of injecting 1-hexene at 100ml / hr in the second reactor was carried out in the same manner as in Example 1 except that 1-butene was injected at 70ml / hr.

Example 3

In the second reactor was carried out in the same manner as in Example 1 except that the 1-hexene was injected at 100ml / hr, the molecular weight regulator was injected at 40㎛ol / hr.

Comparative Example 1

Except that the molecular weight regulator was not used in Example 3 was carried out in the same manner as in Example 3.

Comparative Example 2

A conventional blow molding polyethylene product (BE0350, manufactured by LG Chem) which is manufactured using a continuous CSTR reactor, using a Ziegler catalyst instead of a metallocene catalyst, and without using a molecular weight regulator.

Comparative Example 3

A conventional blow molding polyethylene product (5502HS, manufactured by Daelim Industrial Co., Ltd.) manufactured using a chromium catalyst calcined in a loop reactor and manufactured by including 1-hexene as a comonomer.

[Test Example]

The properties of the polyethylene produced or used in Examples 1 to 3 and Comparative Examples 1 to 3 were measured by the following method, and the results are shown in Table 1 below.

* Molecular weight (MW): measured by weight average molecular weight using gel permeation chromatography (GPC).

* Polydispersity (PDI): The weight average molecular weight was measured by gel permeation chromatography (GPC) divided by the number average molecular weight.

* Die Swell (%): The pelletized product was obtained by cutting the resin when the parison coming out through the blow molding machine (KRUPP KAUTEX, GERMANY) fell 15.7 cm in the vertical direction by measuring its weight.

Die Swell (%) =

As = Vsp × W / L

As: average cross-sectional area of the parison during the shear interval (15.7 cm) (cm ² )

Ad: cross section of die gap (0.6726 cm ² )

Vsp: specific melt volume when polyethylene is not filled

(Specific melting volume) (1.32cm ³ / g)

W: average weight of truncated parisons (g)

L: the gap between scissors (15.7cm)

* Sagging Time (sec): Measured by the time taken for the molten resin falling in the vertical direction through the blow molding machine to reach the 126.5 cm point.

* Formability: The appearance was visually observed and judged to be good when the surface of the product was smooth and there was no bending.

division Example 1 Example 2 Example 3 Comparative Example 1 polymerization continuity continuity continuity continuity Olefin (kg / h) 16.5 16.5 16.5 16.5 Molecular weight regulator
Μmol / hr 80 80 40 0 Copolymer 1-Hexene 1-Butene - - g / hr 70 70 R1 MI (@ 5kg) 30 30 30 30 MI (@ 2kg) 0.19 0.17 0.18 1.5 MI (@ 5kg) 0.85 0.80 0.76 4.8 MI (@ 21.6kg) 16.4 15.7 14.5 53 MFR 86 92 81 35 MW 231,617 215,326 237,480 153,484 PDI 9.4 9.5 9.2 6.4 density 0.955 0.956 0.960 0.962

(R1 MI (@ 5kg) is a measure of the MI (@ 5kg) of the polyethylene powder staying in the first reactor of the multi-stage CSTR reactor, MI (@ 5kg) is the MI of polyethylene passed through the post reactor and drying process (@ 5 kg) means)

As shown in Table 1, the polyethylene according to the present invention (Examples 1 to 3) has a significantly lower melt index (MI) compared to polyethylene (Comparative Example 1) prepared without a molecular weight modifier, molecular weight and polydispersity (PDI) ) Was found to be very high.

In addition, when looking at the molecular weight distribution curve (Molecular Weight Distribution Curve) shown in Figure 2, the polyethylene according to the present invention (Example 1) is observed two peaks, polyethylene prepared without a molecular weight regulator (Comparative Example 1) is a Only peaks were observed.

Properties How to measure Example 1 Example 2 Example 3 Comparative Example 2 Comparative Example 3 MI (@ 2kg) ASTM D1238 0.19 0.17 0.18 0.25 0.20 MI (@ 5kg) 0.85 0.80 0.76 0.94 0.89 MI (@ 21.6kg) 16.4 15.7 14.5 12.0 MFR 86 92 81 48 Density (kg / m3) ASTM D792 0.955 0.956 0.960 0.958 0.960 Flexural Strength (Mpa) ASTM D790 1320 1340 1420 1360 (1400) Stress crack resistance (FNCT) (hr, 80 degrees / 3.5MPa) ISO 16770 100 30 10 3 3 Die Swell (%) 210 200 190 180 210 Sagging Time (sec) 23 24 24 20 23 Formability (Appearance) Good Good Good Good Good

As shown in Table 2, the polyethylene according to the present invention (Example 1 to 3) is a conventional polyethylene (Comparative Example 2) prepared without a molecular weight regulator and a conventional polyethylene (Comparative Example 3) prepared in a loop reactor In comparison, the parison sagging time was improved and the stress cracking resistance (FNCT) was significantly excellent.

Claims (18)

A method for producing a polyolefin, wherein the olefin is polymerized under a metallocene catalyst and a molecular weight regulator. The method of claim 1,
The polymerization is characterized in that carried out in a cascade-CSTR reactor
Method for producing polyolefin. The method of claim 2,
The multistage-CSTR reactor. It characterized in that it comprises a first reactor, a second reactor and a post reactor (Post Reactor)
Method for producing polyolefin. The method of claim 3, wherein
A metallocene catalyst and an olefin are introduced into the first reactor, and a molecular weight regulator is added to the second reactor.
Method for producing polyolefin. The method of claim 3, wherein
The temperature of the second reactor is +20 to -40 ℃ compared to the temperature of the first reactor, characterized in that
Method for producing polyolefin. The method of claim 3, wherein
The pressure of the second reactor, characterized in that +1 to -5 bar compared to the pressure of the first reactor
Method for producing polyolefin. The method of claim 3, wherein
Characterized in that the olefin and another α-olefin is further added to the second reactor as a comonomer.
Method for producing polyolefin. 8. The method of claim 7,
The α-olefin is characterized in that 0.01 to 30 parts by weight based on 100 parts by weight of the total olefins.
Method for producing polyolefin. The method of claim 1,
The polymerization is carried out, further comprising an alkyl aluminum compound
Method for producing polyolefin. The method of claim 1,
The olefin is ethylene, propylene, 1-butene, 1-hexene, 1-octene, 1-pentene, 4-methyl-1-pentene, 1-hexene, 1-heptene, 1-decene, 1-undecene, 1 At least one member selected from the group consisting of dodecene, norbornene, ethylidenenorbornene, styrene, alpha-methylstyrene and 3-chloromethylstyrene;
Method for producing polyolefin. The method of claim 1,
The metallocene catalyst is a hybrid supported metallocene catalyst comprising a first metallocene compound, a second metallocene compound, a promoter and a carrier.
Method for producing polyolefin. The method of claim 1,
The molecular weight modifier is an organometallic complex prepared by reacting a cyclopentadienyl ligand compound represented by the following formula (1) and an organoaluminum compound represented by the following formula (2)
Method for producing polyolefin
[Formula 1]
C _p ¹ C _p ² MX ₂
In Formula 1, C _p ¹ and C _p ² are independently a cyclopentadienyl group selected from a cyclopentadienyl group, a substituted cyclopentadienyl group, an indenyl group, a substituted indenyl group, a fluorenyl group, and a substituted fluorenyl group Is a ligand with a group, M is a group IV element on the periodic table, and X is a halogen element.)
(2)
R ₁ R ₂ R ₃ Al
(In Formula 2, R ₁ , R ₂ and R ₃ are independently a C ₁ ~ C ₂₀ alkyl group or halogen.) The method of claim 1,
Wherein the molecular weight modifier is 10 ^-7 to 10 ^-1 parts by weight based on 100 parts by weight of the total of the olefins
Method for producing polyolefin. A polyolefin prepared according to the method for producing a polyolefin according to any one of claims 1 to 14. The method of claim 14,
The polyolefin has a polymodal molecular weight distribution. The method of claim 14,
The polyolefin has a weight average molecular weight of 100,000 to 700,000 polyolefin. The method of claim 14,
The polyolefin is a polyolefin for blow molding. A hollow molded article made of the polyolefin of claim 14, which is prepared by a blow molding process.

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