KR20140040665A - Preparation method for polyethylene resin and polyethylene resin having high escr and melt tension - Google Patents

Abstract

The present invention relates to a method for manufacturing polyethylene resin comprising: a first reaction step to solely polymerize ethylene monomers or with α-olefin mixed in the presence of Ziegler-Natta polymerization catalyst and hydrogen; and an (n+1)^th reaction step for making the reaction product of an n^th reaction step react with one or more kinds of compounds selected from the group consisting of ethylene monomers and α-olefin, wherein n is an integer greater than or equal to 2. The present invention relates to polyethylene resin having an environmental stress crack resistance (ESCR) of 200-3,000 hours and a melt tension greater than or equal to 100,000 pa·s at a temperature of 190°C and a shear velocity of 0.01 rad/s. [Reference numerals] (AA) Example 1; (BB) Example 2; (CC) Example 3; (DD) Comparative example; (EE) Reference example

Description

Process for producing polyethylene resin and polyethylenic resin having high environmental stress cracking resistance and melt tension {PREPARATION METHOD FOR POLYETHYLENE RESIN AND POLYETHYLENE RESIN HAVING HIGH ESCR AND MELT TENSION}

The present invention relates to a process for producing polyethylene resins and to polyethylenic resins having high environmental stress cracking resistance and melt tension. More specifically, it has excellent mechanical properties such as high flexural strength and impact strength, and can improve moldability or resin processability by securing high environmental stress cracking resistance and melt tension, and can be processed into various shapes or types of resin molded articles. It relates to a method for producing a polyethylene resin that can be and to a polyethylene resin provided by the production method.

Ziegler-Natta catalysts widely applied to the synthesis of conventional polyolefin resins are multi-active catalysts, and thus have a relatively wide molecular weight distribution of the polymer to be synthesized, but the composition of the comonomer is not uniform or the physical properties of the final composite It was not easily adjusted. In addition, the polyolefin resin synthesized using the Ziegler-Natta catalyst may not be sufficiently secured in mechanical properties or processability, and there are cases in which it is limited in various fields or there is a certain limitation in the molding method.

Accordingly, various methods have been attempted to improve not only the mechanical properties but also the processability of the final product in the process of synthesizing the polyolefin resin using the Ziegler-Natta catalyst or molding the produced resin.

Korean Patent Laid-Open Publication No. 2009-0092298 discloses a method of obtaining a crosslinked polyolefin resin by adding a peroxide to an ethylene polymer synthesized using a Ziegler-Natta catalyst. As cross-linking is formed by adding peroxide to the ethylene polymer, the molecular weight distribution and environmental stress cracking resistance (ESCR) of the final product may be increased to a certain degree, but as peroxide is used to prevent decomposition or oxidation of the polymer, Or an antioxidant such as ginseng salt should be added, there is a limit that the quality of the final product can be reduced by the addition of the peroxide and antioxidant.

Korean Unexamined Patent Publication No. 2010-0016232 discloses a method for producing bimodal polyethylene using at least one reactor in the presence of a Ziegler-Natta polymerization catalyst, and the polyethylene produced according to the method has a high density and excellent environmental stress. It has been shown to have cracking (ESCR) and improved bending modules. The Korean Laid-open Patent discloses bimodal polyethylene having improved mechanical properties by increasing the weight average molecular weight and density. Such bimodal polyethylene may have a certain degree of increase in physical properties such as flexural modulus. Or there was a limit that the resin processability is not sufficiently secured.

Accordingly, it is necessary to develop a method for manufacturing various polyolefin resin molded articles by improving moldability or resin processability while securing excellent mechanical properties.

Korean Patent Publication No. 2009-0092298 Korean Patent Publication No. 2010-0016232

The present invention, while having excellent mechanical properties, such as high bending strength and impact strength, can be improved in formability or resin processability by securing high environmental stress cracking resistance and melt tension and can be processed into a resin molded article of various forms or types It is to provide a method for producing a polyethylene resin that can be.

In addition, the present invention has excellent mechanical properties, such as high bending strength and impact strength, while ensuring high environmental stress cracking resistance and melt tension to improve the formability or resin processability and processed into a resin molded article of various forms or types To provide a polyethylene resin that can be.

The present invention comprises a first reaction step of polymerizing in the presence of a Ziegler-Natta polymerization catalyst and hydrogen, alone or mixed with an α-olefin; And an n + 1 reaction step of reacting the reaction product of the nth reaction step with at least one compound selected from the group consisting of ethylene monomers and α-olefins, wherein n is an integer of 2 or more. To provide.

The present invention also provides a polyethylene resin having an environmental stress cracking resistance (ESCR) of 200 to 3,000 hours and a melt tension of 10,000 pa · s or more at a temperature of 190 ° C. and a shear rate of 10 rad / s.

Hereinafter, a method for preparing a polyethylene resin and a polyethylene resin according to specific embodiments of the present invention will be described in detail.

According to one embodiment of the invention, in the presence of a Ziegler-Natta polymerization catalyst and hydrogen, the first reaction step of polymerizing the ethylene monomer alone or mixed with α-olefin; And an n + 1 reaction step of reacting the reaction product of the nth reaction step with at least one compound selected from the group consisting of ethylene monomers and α-olefins, wherein n is an integer of 2 or more. This may be provided.

The inventors of the present invention have conducted studies on improving mechanical properties, formability or processability of polyethylene resins synthesized using a Ziegler-Natta polymerization catalyst, and when applied to the specific manufacturing method, high bending strength and impact strength, etc. Experiment that it is possible to provide a polyethylene resin that can be processed into a variety of forms or types of resin molded products can be improved in formability or resin processability by securing high mechanical stress cracking resistance and melt tension while having excellent mechanical properties Confirmed through and completed the invention.

As described above, in the first reaction step, a synthesis reaction may be performed with the ethylene monomer alone to form an ethylene polymer, and the ethylene monomer and the α-olefin may be mixed to proceed with the synthesis reaction. Coalescing may be formed.

In a second reaction step or nth reaction step (n is an integer of 2 or more) subsequent to the first reaction step, the reaction product of the second reaction step or the nth reaction step is composed of ethylene monomer and α-olefin. By reacting with at least one monomer selected from the group, it is possible to form a copolymer having a higher molecular weight than the ethylene / α-olefin copolymer formed in the first reaction step.

In the method of manufacturing the polyethylene resin, the first reaction step and the nth reaction step (where n is an integer of 2 or more) may be continued in series.

Each of the first reaction step and the nth reaction step (where n is an integer of 2 or more) may apply different temperature or pressure conditions.

Each of the first reaction step and the nth reaction step (where n is an integer of 2 or more) may be performed under a temperature of 50 ° C. to 100 ° C. and a pressure condition of 10 psi to 15,000 psi.

In each of the first reaction step and the nth reaction step (where n is an integer of 2 or more), a Ziegler-Natta polymerization catalyst and hydrogen may be added and used.

In the method for preparing the polyethylene resin, a Ziegler-Natta polymerization catalyst known to be used for the synthesis of the polyolefin resin may be used without any limitation, but the Ziegler-Natta polymerization catalyst may be a magnesium compound; An alkyl aluminum compound of Formula 1; Transition metal compounds; It is preferable to include an internal electron donor comprising at least one compound selected from the group consisting of a compound of Formula 2 and a compound of Formula 3.

[Chemical Formula 1]

R ¹ AlX _{3 -l}

In Formula 1, R ¹ is a linear or branched alkyl group having 1 to 10 carbon atoms, l is an integer of 1 to 3, X is a halogen.

(2)

(3)

In Formulas 2 to 3, R ² , R ³ and R ⁴ may be the same or different from each other, each hydrogen, a straight chain, branched or cyclic alkyl group of 1 to 20 carbon atoms (Alkyl), alkenyl group of 2 to 20 carbon atoms (Alkenyl), cycloalkyl group having 3 to 20 carbon atoms, aryl group having 3 to 20 carbon atoms (Aryl), alkylsilyl group having 1 to 20 carbon atoms (Alkylsilyl), arylalkyl group having 7 to 20 carbon atoms, and carbon atoms It is an alkyl group containing a 7-20 alkylaryl group (Alkylaryl) group, or a C2-C20 hetero atom.

The magnesium compound may include at least one member selected from the group consisting of magnesium halide, alkoxy magnesium, alkyl magnesium halide, magnesium alkoxy halide and magnesium allyloxyhalide.

Specific examples of the magnesium compound include magnesium halides such as magnesium chloride, magnesium dichloride, magnesium bromide, magnesium fluoride, or magnesium iodide; Magnesium alkoxy halides such as magnesium methoxide chloride, magnesium ethoxy chloride, magnesium isopropoxy chloride, magnesium chloride butoxide, or magnesium octoxy chloride; Allyloxyhalogenated magnesium such as phenoxy magnesium chloride; And alkoxy magnesium such as ethoxy magnesium, isopropoxy magnesium, or butoxy magnesium; Etc., and it is preferable to use magnesium halide because it increases the activity of the catalyst. Among them, magnesium dichloride is preferably used because it exhibits stable and high activity in terms of structure and coordination with the transition metal compound, which is the main active metal.

The transition metal compound may include a transition metal compound of Formula 4 below. The transition metal compound means a transition metal of Group IVB, VB, or VIB or an organic compound containing such a transition metal. Specific examples of the transition metal include Ti, Zr, Hf, Rf, V, Nb, Ta , Db, Cr, Mo, W, and Sg.

[Chemical Formula 4]

MX _n (OR ⁵ ) _4-n

In the formula (4), M is selected from the group consisting of transition metal elements of Group IVB, VB and VIB of the periodic table, X is halogen, R ⁵ is an alkyl group having 1 to 10 carbon atoms, and n is 0 to 4 as an oxidation number of metal.

The Ziegler-Natta polymerization catalyst, the step of reacting the magnesium compound with alcohol to prepare a magnesium compound solution; And it may be obtained through the step of reacting the magnesium compound solution and the alkylaluminum including the compound represented by the formula (1), the transition metal compound, and the internal electron donor comprising the compound represented by the formula (2) to (3).

In the preparation of the catalyst for polyethylene synthesis, the magnesium compound may be reacted with alcohol to prepare a magnesium compound solution.

The alcohol may be used without limitation as long as it is an alcohol known to be used for preparing a Ziegler-Natta catalyst for polyethylene synthesis. Specific examples of the solvent include ethanol, n-propanol, isopropanol, n-butanol, isobutanol, n-pentanol, isopentanol, neopentanol, cyclopentanol, n- Aliphatic or alicyclic alcohols such as dodecanol, 2-methylpentanol, 2-ethylbutanol and 2-ethylhexanol; Aryl cyclic alcohols such as cyclohexanol and methylcyclohexanol; Or aromatic alcohols such as benzyl alcohol, methylbenzyl alcohol, isopropylbenzyl alcohol and? -Methylbenzyl alcohol; Among them, it is preferable to use an aliphatic or alicyclic alcohol. Since the alcohol having a cyclic or benzene ring has a large molecular size, the reactivity is poor and the reaction proceeds slowly, so ethanol having a relatively short chain length is used .

The alcohol may react with the magnesium compound to dissolve the magnesium compound, The compound swells to expand the surface area. Further, by adding the alcohol, The compound can be swollen and there is no need to prepare a homogeneous solution at a high temperature. The solution is sufficiently stirred at a temperature of 0 to 40 ° C for about 30 minutes to 2 hours, and a magnesium compound is reacted with an alcohol to prepare a highly active catalyst .

The reaction molar ratio of the magnesium compound and the alcohol may be 1: 0.5 to 1:10, preferably 1: 2 to 1: 8. When the reaction molar ratio of the alcohol is more than 10 moles relative to the magnesium compound, the amount of the transition metal compound to be reacted with the magnesium compound must be increased in order to exhibit high activity, which is not preferable from the economical point of view. The yield may be small, which is undesirable.

The magnesium solution may be prepared by reacting the magnesium compound with an alcohol in the presence of a hydrocarbon solvent. When the reaction is carried out in the presence of a hydrocarbon solvent as described above, a homogeneous solution of a magnesium compound and an alcohol can be obtained while using a small amount of alcohol.

Specific examples of the hydrocarbon solvent include aliphatic or alicyclic hydrocarbons having 5 to 20 carbon atoms, and aliphatic or alicyclic hydrocarbon solvents having 8 to 17 carbon atoms are most preferred. More specific examples include aliphatic hydrocarbons such as hexane, heptane, octane, decane, dodecane, tetradecane, and mineral oil; Alicyclic hydrocarbons such as cyclic hexane, cyclic octane, methyl cyclic pentane and methyl cyclic hexane; And aromatic hydrocarbons such as benzene, toluene, xylene, ethylbenzene, and cumene.

The hydrocarbon solvent is preferably reacted at a rate of 5 to 20 mol per 1 mol of the magnesium compound. If the amount of the hydrocarbon solvent is less than the above range, it is difficult to obtain a homogeneous solution of the magnesium halide compound at a low temperature. If the amount is larger than the above range, the reactor capacity may increase in the process and the temperature may be difficult to control.

In the step of reacting the magnesium compound solution with the internal electron donor comprising the alkyl aluminum, the transition metal compound and the compound represented by the above formulas 2 to 3 containing the compound represented by the formula 1, The sequence or order of insertion is not limited. For example, the magnesium compound solution, the alkyl aluminum, the transition metal compound, and the internal electron donor may be reacted simultaneously, or the components may be sequentially added to react.

However, in order to increase the activity of the catalyst, an inner electron donor including the magnesium compound solution, the alkylaluminum including the compound represented by the formula (1), the transition metal compound, and the compound represented by the formula (2) Reacting the magnesium compound solution with an alkylaluminum compound including the compound represented by Formula 1, and reacting the magnesium compound solution and the reaction product of the alkylaluminum with a transition metal compound represented by Formula 2 to Formula 3 With an internal electron donor comprising a compound of formula < RTI ID = 0.0 > (I) < / RTI >

More specifically, alcohol and magnets? In the reaction of the compound, the alcohol diligently expands the magnesium compound to secure a space where a large number of active points can be generated, and reacts with the alkyl aluminum immediately, thereby generating a large amount of the active point by removing the alcohol attached to the magnesium compound. have. That is, the alkylaluminum compound is reacted with the magnesium compound solution to increase the activity of the finally prepared catalyst for polyethylene polymerization, and by polymerizing polyethylene using such a catalyst, polyethylene having a wide molecular weight distribution can be obtained.

The alkyl aluminum may include at least one compound represented by the formula (1), and specific examples of the compound represented by the formula (1) include triethyl aluminum, trimethyl aluminum, triisopropyl aluminum, trioctyl aluminum, diethyl aluminum chloride , Diethylaluminum bromide, diethylaluminum iodide, diethylaluminum fluoride, ethylaluminum dichloride, dimethylaluminum chloride, methylaluminum dichloride, and the like.

The magnesium compound and the alkylaluminum can be reacted at a molar ratio of 1: 0.01 to 1: 5, preferably at a molar ratio of 1: 0.5 to 1:10. When the amount of the alkylaluminum compound is less than 0.01 mol per mol of the magnesium compound, the molecular weight distribution of the polyethylene produced may not increase, and when it exceeds 50 mol, the catalytic activity may drop sharply.

The reaction temperature of the magnesium compound solution and the alkylaluminum compound is preferably -50 to 150 ° C, particularly preferably 0 to 100 ° C. If it is out of the above temperature range, the reactants do not sufficiently react to deteriorate the activity or increase the side reactions are undesirable. In addition, the reaction time is preferably carried out for 0.5 to 24 hours from the start of the reaction.

In addition, the polyethylene compound catalyst may be prepared by reacting the solution of the magnesium compound solution with the alkyl aluminum in sequence with an internal electron donor including a transition metal compound and the compound represented by Formulas 2 to 3.

The magnesium compound and the transition metal compound may be reacted at a molar ratio of 1: 0.1 to 1:50, preferably at a molar ratio of 1: 1 to 1:10. When the amount of the transition metal compound is less than 0.1 mole per mole of the magnesium compound, the activity of the catalyst to be produced may be reduced, or the stereoregularity of the polyethylene synthesized using the same may be undesirable.

The temperature at which the transition metal compound is added to the solution obtained by reacting the magnesium compound solution with the alkylaluminum may be -50 to 150 ° C, preferably -20 to 100 ° C. The reaction process can be carried out by stirring the magnesium compound solution and the reaction product of the alkylaluminum in the reactor and adding a certain amount of the transition metal compound to the reaction product for about 2 hours. The slow administration of the transition metal compound is preferable because the transition metal compound can prevent the side reaction that may occur due to rapid reaction with other compounds.

Then, the reaction is performed by administering a transition metal compound, and then the temperature of the reactant is increased and the reaction is performed by administering an internal electron donor.

The internal electron donor contributes an electron to a transition metal compound in a polymerization catalyst for synthesizing polyethylene to form an active point of the catalyst, thereby increasing the catalytic activity and synthesizing polyethylene having improved stereoregularity. Can be. Specifically, the ethylbenzoate or diisobutylphthalate has one or two acyl groups in the benzene ring, and has a structure in which the above-mentioned specific functional groups of R ² to R ⁴ are bonded at specific positions. That is, this chemical structure can strongly bind to the catalytic active site and can act as a nucleating agent for increasing the degree of crystallization. Accordingly, the internal electron donor including the compounds represented by Chemical Formulas 2 to 3 can more effectively increase the activity of the catalyst, and can reduce the amount of the internal electron donor through the role of the nucleating agent.

The internal electron donor may be reacted with 0.1 to 5 moles, preferably 0.1 to 1 mole, per mole of the magnesium compound. When the internal electron donor is allowed to react outside the above range, it is not preferable because the uniformity of the active point of the finally obtained catalyst for polyethylene synthesis can be lowered.

Then, the product of reacting the internal electron donor is washed with a hydrocarbon solvent, the catalyst particles are precipitated, and the supernatant is removed several times, and the catalyst particles from which the transition metal compound is removed are flowed under nitrogen flowing for 2 hours or more. Ventilation and drying may prepare a catalyst for the final polyethylene polymerization.

On the other hand, in order to improve resin moldability or resin processability by securing high environmental stress cracking resistance and high melt tension while having excellent mechanical properties such as better bending strength and impact strength, Halogenated compounds may comprise particles of various sizes, or may have a wide particle size distribution.

Specifically, the Ziegler-Natta polymerization catalyst is 2 wt% to 40 wt% of particles having a maximum diameter of more than 500 μm; 10 wt% to 35 wt% of particles having a maximum diameter of less than 120 μm; And it may include a particle having a maximum diameter of the residual amount of 120㎛ to 500㎛. In addition, the halogenated compound of the transition metal bonded to the carrier is 2 to 40wt% of particles having a maximum diameter of more than 500㎛ 1000㎛, 10wt% to 35wt% of particles having a maximum diameter of 50㎛ more than 120㎛; And it may include a particle having a maximum diameter of the residual amount of 120㎛ to 500㎛.

The α-olefins usable in the polyethylene resin production method include at least one member selected from the group consisting of 1-butene, 1-pentene, 1-hexene, 4-methyl, 1-pentene, 1-heptene, and 1-octene. A monomer can be mentioned. By selecting an appropriate? -Olefin in the production method of the polyethylene resin, it is possible to appropriately control the environmental stress cracking resistance and the melt tension of the polyethylene resin produced.

On the other hand, according to the above-described manufacturing method, a polyethylene resin capable of improving moldability or resin processability by securing high environmental stress cracking resistance and melt tension while having excellent mechanical properties such as high bending strength and impact strength, or α -Olefin / ethylene copolymers may be provided.

In addition, the polyethylene resin or α-olefin / ethylene copolymer may have a molecular weight distribution of bimodal or multimodal. The polyethylene resin or α-olefin / ethylene copolymer has a relatively low density and can implement the properties of high density polyolefin can exhibit excellent mechanical properties and processability.

Meanwhile, according to another embodiment of the present invention, a polyethylene resin having an environmental stress crack resistance (ESCR) of 200 to 3,000 hours and a melt tension of 10,000 pa · s or more at a temperature of 190 ° C. and a shear rate of 10 rad / s is obtained. Can be provided.

Such polyethylene resins may have a melt tension of at least 100,000 pa.s at a temperature of 190 ° C. and a shear rate of 0.01 rad / s.

The polyethylene resin may have a higher melt tension during high temperature extrusion molding and thus may have higher moldability or processability. Specifically, the polyethylene resin may have a melt tension of at least 100,000 pa.s at a temperature of 190 ° C. and a low shear rate, for example 0.01 rad / s, and a higher shear rate, for example 10 rad / s. It can have a melt tension of 10,000 pa. or more at a shear rate of s.

The polyethylene resin may be an α-olefin / ethylene copolymer.

In addition, the polyethylene resin may have a density of 0.940 to 0.959 g / cc, or 0.945 to 0.953.

 In addition, the polyethylene resin may have a molecular weight distribution of 12 or more, or a molecular weight distribution of 13 to 20.

According to the present invention, while having excellent mechanical properties such as high flexural strength and impact strength, high environmental stress cracking resistance and melt tension can be secured to improve the formability or resin processability and processed into a resin molded article of various forms or types It can provide a polyethylene resin that can be.

1 is a result of measuring the melt tension of the polyethylene resin obtained in Examples, Comparative Examples and Reference Examples.
Figure 2 shows the gel permeation chromatography measurement results of Example 1.
Figure 3 shows the gel permeation chromatography measurement results of Example 2.
Figure 4 shows the gel permeation chromatography measurement results of Example 3.
5 shows the results of gel permeation chromatography measurement of the comparative example.
Figure 6 shows the results of the gel permeation chromatography measurement of the Reference Example.

The invention will be described in more detail in the following examples. However, the following examples are illustrative of the present invention, and the present invention is not limited by the following examples.

[ Sangsangye : Ziegler - Appear  Preparation of Catalyst]

A 300 ml pressure-resistant glass reactor equipped with a stirrer and an oil circulating heater was sufficiently evacuated with nitrogen and 110 ml of hexane was charged into the reactor under a nitrogen atmosphere. 5.71 g of anhydrous magnesium dichloride was added to the reactor and stirred at room temperature. 21 ml of ethanol was gradually added over 1 hour and stirred at 300 rpm for 1 hour or more to sufficiently react the anhydrous magnesium dichloride and ethanol.

20 ml of diethyl aluminum chloride and 20 ml of hexane were mixed and the alkylaluminum compound diluted to 50% was slowly added to the mixture of magnesium anhydrous magnesium dichloride and ethanol at 25 ° C at a rotation speed of 400 rpm, Respectively. After completion of the addition, the stirring speed was increased to 500 rpm and reacted for 2 hours.

Then, 20 ml of titanium tetrachloride was slowly added to the heterogeneous mixed solution thus prepared at 25 ° C., held for 30 minutes, and heated slowly. 0.26 ml of ethylbenzoate was injected into the internal electron donor at 73 ° C. and reacted for 3 hours. When the reaction was completed, the temperature was lowered to 50 ° C. to stop stirring, and the resulting catalyst was precipitated to remove the supernatant, 200 ml of hexane was added, and then rinsed sufficiently. This process was repeated six or more times to prepare a catalyst for polyethylene synthesis.

[ Example : Preparation of Polyethylene Resin Using a plurality of Reactors Connected in Series]

In the presence of the synthesized Ziegler-Natta catalyst and hydrogen, the ethylene monomers were polymerized in a first reactor. The polymerization product obtained in the first reactor was introduced into a second reactor connected in series with the first reactor, and an α-olefin / ethylene copolymer was synthesized in the presence of a Ziegler-Natta catalyst and hydrogen. The contents of the polyethylene resins obtained in Examples 1 to 3 are shown in Table 1 below.

 [ Comparative Example : Production of Polyethylene Resin Using One Reactor]

In the presence of a Ziegler-Natta catalyst and hydrogen, the ethylene monomer and the α-olefin were reacted in one reactor to form a copolymer.

[ Reference example : Preparation of Polyethylene Resin Using Catalyst with Narrow Particle Size Distribution]

Α-olefin / ethylene copolymer was synthesized in the same manner as in Example 1, except that the Ziegler-Natta catalyst including particles having a particle size distribution different from that of the Ziegler-Natta catalyst was used.

The contents of the polyether resins obtained in Examples, Comparative Examples and Reference Examples are shown in Table 1 below. The gel permeation chromatography (GPC) measurement results of the polyether resins of the examples, the comparative examples, and the reference examples are as shown in FIGS. 2 to 6.

Synthesis Results of Examples, Comparative Examples and Reference Examples unit Example 1 Example 2 Example 3 Comparative Example 1 Reference Example 1 Polymerization process Bimodal Bimodal Bimodal Monomodal Bimodal Molecular weight distribution 13.37 17.51 15.15 4.49 9.97 density g / cc 0.958 0.950 0.941 0.954 0.959 Melt Index g / 10min 0.15 0.05 0.27 0.62 0.32

[ Experimental Example : Polyether  Measurement of resin properties]

The physical properties of the polyether resins synthesized in the Examples, Comparative Examples and Reference Examples were measured by the following methods.

1. Tensile strength and elongation: measured based on ASTM D 683

2. Flexural modulus: measured based on ASTM D 790

3. Environmental stress crack resistance (ESCR): measured based on ASTM D 1693

4. Melt tension: After viscoelastic analysis at 190 ° C and 0.01 to 500 rad / s with an ARES rheometer, the melt tension was calculated by calculating the zero-shear viscosity using the Ellis model.

The results of Experimental Examples 1 to 4 are shown in Table 2 below.

Mechanical property, ESCR property, Melt tension analysis result unit Example 1 Example 2 Example 3 Comparative Example 1 Comparative Example 2 Tensile strength (yield point stress) kgf / cm ² 288 258 221 231 283 Elongation % > 500 > 500 > 500 > 500 > 500 Flexural modulus kgf / cm ² 13,500 9,100 8,200 9,100 14,000 ESCR F50HR 224 1,566 > 2,000 21 43 Melt tension pa? 249,335 1,740,000 317,845 18,359 38,257

As shown in Table 2, the polyethylene resin obtained in the embodiment can improve moldability or resin processability by securing high environmental stress cracking resistance and melt tension while having excellent mechanical properties such as high bending strength and impact strength. It was confirmed that there is.

In addition, as can be seen in Figure 1, the polyethylene resin obtained in the example may have a melt tension of 100,000 pa.s or more at a temperature of 190 ° C and a low shear rate, for example, a shear rate of 0.01 rad / s, more Since it may have a melt tension of 10,000 pa · s or more at a high shear rate, for example, a shear rate of 10 rad / s, it may have a higher melt tension during high temperature extrusion and may have higher moldability or processability.

Claims (14)

In the presence of a Ziegler-Natta polymerization catalyst and hydrogen, a first reaction step of polymerizing the ethylene monomer alone or by mixing with α-olefin; And
And an n + 1 reaction step of reacting the reaction product of the nth reaction step with at least one compound selected from the group consisting of ethylene monomers and α-olefins.
The said n is an integer of 2 or more, The manufacturing method of polyethylene resin.
The method of claim 1,
Each reaction step applies a different temperature or pressure conditions, the method of producing a polyethylene resin.
3. The method of claim 2,
Wherein each reaction step is performed under a temperature of 50 ° C. to 100 ° C. and a pressure condition of 10 psi to 15,000 psi.
The method of claim 1,
The Ziegler-Natta polymerization catalyst is a magnesium compound; An alkyl aluminum compound of Formula 1; Transition metal compounds; A method for preparing a polyethylene resin comprising an internal electron donor comprising at least one compound selected from the group consisting of a compound of Formula 2 and a compound of Formula 3:
[Chemical Formula 1]
R ¹ AlX _{3 -l}
Wherein R ¹ is a straight or branched alkyl group having 1 to 10 carbon atoms, 1 is an integer of 1 to 3, X is halogen,
(2)

(3)

In Formulas 2 to 3, R ² , R ³ and R ⁴ may be the same or different from each other, each hydrogen, a straight chain, branched or cyclic alkyl group of 1 to 20 carbon atoms (Alkyl), alkenyl group of 2 to 20 carbon atoms (Alkenyl), cycloalkyl group having 3 to 20 carbon atoms, aryl group having 3 to 20 carbon atoms (Aryl), alkylsilyl group having 1 to 20 carbon atoms (Alkylsilyl), arylalkyl group having 7 to 20 carbon atoms, and carbon atoms It is an alkyl group containing a 7-20 alkylaryl group (Alkylaryl) group, or a C2-C20 hetero atom.
5. The method of claim 4,
The Ziegler-Natta polymerization catalyst
0.1 mol to 50 mol of the transition metal compound relative to 1 mol of the magnesium compound; 0.1 mol to 5 mol of the internal electron donor; And 0.01 mol to 5 mol of an alkyl aluminum compound of Chemical Formula 1;
5. The method of claim 4,
The magnesium compound comprises at least one member selected from the group consisting of magnesium halides, alkoxy magnesium, alkyl magnesium halides, magnesium alkoxy halides and magnesium allyloxyhalides.
5. The method of claim 4,
The transition metal compound comprises a transition metal compound of Formula 4, a method for producing a polyethylene resin:
[Chemical Formula 4]
MX _n (OR ⁵ ) _4-n
In the formula (4), M is selected from the group consisting of transition metal elements of Group IVB, VB and VIB of the periodic table, X is halogen, R ⁵ is an alkyl group having 1 to 10 carbon atoms, and n is 0 to 4 as an oxidation number of metal.
5. The method of claim 4,
The Ziegler-Natta polymerization catalyst,
2 to 40 wt% of particles having a maximum diameter of greater than 500 μm;
10 to 35 wt% of particles having a maximum diameter of less than 120 μm; And
A method for producing a polyethylene resin, comprising particles having a residual diameter of a maximum diameter of 120 μm to 500 μm.
The method of claim 1,
The α-olefin comprises at least one monomer selected from the group consisting of 1-butene, 1-pentene, 1-hexene, 4-methyl, 1-pentene, 1-heptene and 1-octene, a method for producing a polyethylene resin .
A polyethylene resin having an environmental stress crack resistance (ESCR) of 200 to 3,000 hours and a melt tension of 10,000 pa · s or more at a temperature of 190 ° C. and a shear rate of 10 rad / s.
11. The method of claim 10,
A polyethylene resin having a melt tension of at least 100,000 pa · s at a temperature of 190 ° C. and a shear rate of 0.01 rad / s.
11. The method of claim 10,
The polyethylene resin is an α-olefin / ethylene copolymer.
11. The method of claim 10,
Polyethylene resin having a density of 0.940 to 0.959 g / cc.
11. The method of claim 10,
Polyethylene resin having a molecular weight distribution of 12 or more.

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