Polymerization method of ultra-high molecular weight polyethylene and preparation method of catalyst thereof

Abstract

The present disclosure provides a method for polymerizing ultra-high molecular weight polyethylene and a method for preparing a catalyst thereof, in which a main catalyst, a co-catalyst mixed with two or more types of organic aluminum and an organic silane compound are reacted in the polymerization of ultra-high molecular weight polyethylene to have high activity, high bulk density and high molecular weight while having low particle agglomeration.

Description

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application is based on and claims the benefit of priority from Korean Patent Application No. 10-2022-0007430 filed on January 28, 2022, in the Korean Intellectual Property Office, the disclosure of which is incorporated herein by reference in its entirety. Technical Field

[0003] The present disclosure relates to a method for polymerizing ultra-high molecular weight polyethylene having a large molecular weight and a method for preparing a catalyst thereof. Background Art

[0004] Ultra-high molecular weight polyethylene is a type of polyethylene resin with a molecular weight of at least 10 6 g / mol or more polyethylene, and is defined in ASTM 4020 as "a linear polyethylene having a relative viscosity of 2.30 or more at 135°C, which is contained at 0.05% in 100ml of a decalin solution". Ultra-high molecular weight polyethylene has a very large molecular weight compared to general-purpose polyethylene so as to have excellent properties such as rigidity, wear resistance, environmental stress uniformity, self-lubrication, chemical resistance and electrical properties. Due to the excellent physical properties as described above, it can be said that ultra-high molecular weight polyethylene is a high-quality specialty material obtained from general-purpose raw materials.

[0005] Ultra-high molecular weight polyethylene manufactured by a polymerization method has a high molecular weight, so that it cannot be pelletized like general-purpose polyethylene and therefore it is produced and sold as powder. Therefore, it can be said that the size and distribution of polymer powder are very important, and the particle distribution of the polymer and the presence of fine particles are important characteristics of the catalyst.

[0006] As prior art, catalysts and catalyst manufacturing methods for preparing magnesium-containing ultra-high molecular weight polyethylene based on titanium have been reported. Specifically, it is known that a method for obtaining the above-mentioned olefin polymerization catalyst with high bulk density (bulk density) is obtained by using a magnesium solution. U.S. Patent No. 4,962,167 discloses a preparation method for obtaining a catalyst by reacting a reactant magnesium halide compound and a titanium alkoxide compound with a reactant aluminum halide and a silicon alkoxide compound. The catalyst prepared in this way provides a relatively high bulk density, but there is still room for improvement. In addition, it is necessary to improve the activity of the catalyst. In addition, U.S. Patent No. 5,587,440 reports a method for producing a polymer with narrow particle distribution and high bulk density by reducing titanium halide (IV) with an organoaluminum compound and then carrying out a post-treatment process with an organoaluminum compound, but there is a problem of relatively low catalyst activity.

[0007] Korean Patent No. 0822616 discloses a method for producing a titanium-containing catalyst comprising magnesium, titanium, halogen and silane compounds, which can produce ultra-high molecular weight polyolefin polymers having high catalytic activity, high bulk density and narrow molecular weight distribution. Korean Patent No. 0351386 discloses a catalyst for preparing ultra-high molecular weight polyethylene having high catalytic activity, high bulk density and narrow polymer particle distribution and a method for preparing the same, wherein the catalyst is prepared by a method in which a magnesium compound solution is prepared by contacting and reacting a mixture of a magnesium halide compound and an aluminum or boron compound with an alcohol, then reacting the resultant with an ester compound containing at least one hydroxyl group and a silicone compound having an alkoxy group, and then adding a mixture of a titanium compound and a silicone compound. The above two methods use intermittent polymerization, so they have the disadvantage of reduced productivity compared to a continuous polymerization method.

[0008] The activity, bulk density and molecular weight of ultra-high molecular weight polyethylene vary greatly depending on the polymerization conditions. When polymerization is performed by lowering the temperature to increase the molecular weight, productivity decreases due to low activity. Therefore, a technology capable of polymerizing ultra-high molecular weight polyethylene at ordinary polyethylene polymerization temperatures is required. Summary of the invention

[0009] The present disclosure provides a method for polymerizing ultra-high molecular weight polyethylene and a method for preparing a catalyst for the polymerization to effectively polymerize ultra-high molecular weight polyethylene having high activity, high bulk density, high molecular weight, and low particle aggregation.

[0010] The present disclosure provides a method for polymerizing ultra-high molecular weight polyethylene, the method comprising: reacting a main catalyst including a titanium active site, an organoaluminum co-catalyst mixed with two or more types of organoaluminums, and an organosilane compound to polymerize the ultra-high molecular weight polyethylene.

[0011] In addition, the present disclosure provides a method for preparing a main catalyst for ultra-high molecular weight polyethylene polymerization, the method being carried out by reacting a main catalyst containing titanium active sites, an organic aluminum cocatalyst mixed with two or more types of organic aluminums, and an organic silane compound. The method for preparing the catalyst comprises the following steps: preparing a magnesium compound solution by reacting magnesium dichloride (MgCl2) with an alcohol; preparing a precursor by reacting the magnesium compound solution with titanium tetrachloride; and preparing a catalyst by primary reacting the precursor with titanium tetrachloride and then reacting the resultant with a diester compound.

[0012] In addition, the present disclosure includes an ultra-high molecular weight polyethylene having a polymerization activity of 5 kg-PE / g-catalyst to 40 kg-PE / g-catalyst and a viscosity average molecular weight of 2.0×106 g / ml to 10.0×10 6 g / ml, the bulk density is 0.30 g / ml to 0.50 g / ml, and the particles of 1 um or more are aggregated to 8.0 wt% or less.

[0013] The method for polymerizing ultra-high molecular weight polyethylene according to an embodiment of the present disclosure is used to efficiently polymerize ultra-high molecular weight polyethylene having high activity, high bulk density, high molecular weight, and low particle aggregation. DETAILED DESCRIPTION

[0014] Hereinafter, some embodiments of the present disclosure will be described in detail with reference to the illustrative drawings. When adding reference numerals to the components of each drawing, the same components may have reference numerals that are as identical as possible, even if they are indicated in different drawings. In addition, when describing an embodiment of the present invention, when it is determined that a detailed description of a well-known configuration or function may obscure the main points of the technical idea of ​​the present invention, the detailed description may be excluded. When the terms "including", "having", "comprising", etc. mentioned in this specification are used, other parts may be added unless "only" is used. When a component is represented in the singular, multiple components may be included unless otherwise explicitly stated.

[0015] In addition, when describing the components of the present disclosure, terms such as first, second, A, B, (a), (b), etc. may be used. These terms are only used to distinguish the components from other components, and the nature, order, sequence or number of the components are not limited by the terms.

[0016] In the description of the positional relationship of components, when two or more components are described as “coupled”, “combined” or “connected”, the two or more components are directly “coupled”, “combined” or “connected”, but it should be understood that the two or more components and other components may be “coupled”, “combined” or “connected” through an insert. Here, other components may be included in one or more of the two or more components that are “coupled”, “combined” or “connected” to each other.

[0017] In the description of the time process relationship related to components, operating methods or manufacturing methods, for example, "after", "subsequently", "next", "before", etc. are used to describe the time priority relationship or process priority relationship, unless "immediately" or "directly" is used, it may include discontinuous situations.

[0018] At the same time, when referring to the numerical value or corresponding information of a component (for example, level, etc.), even if there is no separate explicit description, the numerical value or corresponding information may be interpreted as including an error range that may be caused by various factors (for example, process factors, internal or external impacts, noise, etc.).

[0019] In the present specification, the organosilane compound may be used as an organosilane external donor or an organosilane external electron donor, but is not limited to these terms.

[0020] The present disclosure provides a method for polymerizing ultra-high molecular weight polyethylene, wherein the method polymerizes ultra-high molecular weight polyethylene by reacting a main catalyst containing a titanium active site, an organic aluminum cocatalyst mixed with two or more types of organic aluminum, and an organic silane compound. The ultra-high molecular weight polyethylene prepared by this method can have a high bulk density and a high molecular weight, and at the same time has excellent polymerization activity.

[0021] For example, the present disclosure provides a method for producing ultra-high molecular weight polyethylene by introducing a procatalyst having titanium active sites, two or more alkylaluminum cocatalysts, and a mixture of an organosilane compound together in a continuous ethylene polymerization reactor.

[0022] Furthermore, the present disclosure provides a method for producing ultra-high molecular weight polyethylene having high activity and high bulk density as well as high molecular weight by combining a main catalyst, two or more types of organoaluminum co-catalysts, and an organosilane compound in a suitable ratio under continuous polymerization conditions.

[0023] The above-mentioned main catalyst can be a Ziegler-Natta catalyst in which titanium is supported on magnesium. The magnesium compound can be a magnesium halide compound, such as magnesium chloride, magnesium dichloride (MgCl2). For example, the above-mentioned main catalyst can be a Ziegler-Natta catalyst based on titanium supported on magnesium dichloride (MgCl2).

[0024] When the main catalyst is a Ziegler-Natta catalyst in which titanium is supported on magnesium dichloride (MgCl2), the main catalyst can be prepared by a method for producing the catalyst, the method comprising: a first step: preparing a magnesium compound solution by reacting magnesium dichloride (MgCl2) with an alcohol; a second step: preparing a precursor by reacting the magnesium compound solution with titanium tetrachloride; and a third step: preparing a catalyst by subjecting the precursor to a primary reaction with titanium tetrachloride and then reacting the resultant with a diester compound represented by the following formula 1;

[0025] [Formula 1]

[0026] R1OOCR2COOR3

[0027] wherein R1 and R3 are straight or branched chain alkyl groups having 1 to 10 carbon atoms, and R2 is a hydrocarbon having 1 to 20 carbon atoms.

[0028] In the method for preparing the catalyst, there is no particular limitation on the type of alcohol, but an alcohol having 4 to 20 carbon atoms is preferred. For example, the alcohol may be n-butanol.

[0029] The alcohol may be mixed in an amount of 3 to 7 parts by weight, for example, 3 to 5 parts by weight, based on 1 part by weight of the magnesium dichloride compound. The hydrocarbon solvent may be mixed in a ratio of 9 to 16 parts by weight, for example, 10 to 15 parts by weight, based on 1 part by weight of the magnesium dichloride compound.

[0030] R2 is a hydrocarbon having 1 to 20 carbon atoms, and may be an aliphatic hydrocarbon, an alicyclic hydrocarbon, or an aromatic hydrocarbon.

[0031] The straight or branched alkyl group having 1 to 10 carbon atoms or the hydrocarbon group having 1 to 20 carbon atoms is substituted or unsubstituted. It may be substituted with one or more substituents selected from the group consisting of: deuterium, C1-C 20 Alkyl, C1-C 20 Alkoxy, C1-C 20 Alkylamine, C1-C 20 Alkylthienyl, C6-C 20 Arylthienyl, C2-C 20 Alkenyl, C2-C 20 Alkynyl, C3-C 20 Cycloalkyl, C6-C 60 Aryl, deuterated C6-C 60 Aryl, C8-C 20 an arylalkenyl group and a C2-C4-alkylene group containing at least one heteroatom selected from the group consisting of O, N, S, Si and P 20 A heterocyclic group, but the substituents are not limited to these substituents.

[0032] The solvent used for polymerizing ultra-high molecular weight polyethylene can be a hydrocarbon solvent. The hydrocarbon solvent can be an aliphatic hydrocarbon having 1 to 20 carbon atoms, such as pentane, hexane, heptane, octane, decane and kerosene; or an alicyclic hydrocarbon, such as cyclopentane, methylcyclopentane, cyclohexane and methylcyclohexane. For example, the solvent used for polymerizing ultra-high molecular weight polyethylene can be a linear, branched and cyclic saturated hydrocarbon, such as propane, butane, isobutane, pentane, cyclopentane, hexane, cyclohexane and heptane.

[0033] The organoaluminum co-catalyst used when polymerizing ultra-high molecular weight polyethylene can be a mixture of two or more types having the structure of AlRnX3-n (n is 1 to 3, R is a straight or branched alkyl group having 1 to 8 carbon atoms, and X is a halogen atom (e.g., F, Cl and Br) or a hydrogen atom).

[0034] The amount of the organic aluminum co-catalyst may be 0.1 mole to 100 moles of aluminum atoms of the co-catalyst per mole of titanium atoms of the main catalyst, but is not limited thereto.

[0035] When polymerizing ultra high molecular weight polyethylene, the organic silane compound used may be a compound represented by Formula 2 below.

[0036] [Formula 2]

[0037]

[0038] In Formula 2, R4, R5, R6 and R7 are each independently a linear, branched and cyclic alkyl group having 1 to 20 carbon atoms; an alkoxy group having 1 to 20 carbon atoms; an aryl group having 6 to 20 carbon atoms; and an alkyl group having 1 to 20 carbon atoms containing a heteroatom.

[0039] Unless otherwise indicated, " aryl " has 6 to 60 carbon atoms, but is not limited thereto. In the present application, aryl can include monocyclic type, cyclic aggregate, condensed polycyclic system, spirocyclic compound etc. For example, aryl includes phenyl, biphenyl, naphthyl, anthracenyl, indenyl, phenanthrenyl, triphenylene, pyrenyl, perylenyl, chrysenyl (chrysenyl), naphthacenyl (naphthacenyl), fluoranthenyl etc., but is not limited thereto. Naphthyl can include 1-naphthyl and 2-naphthyl, and anthracenyl can include 1-anthracenyl, 2-anthracenyl and 9-anthracenyl.

[0040] Unless otherwise specified, "heteroatom" means, but is not limited to, N, O, S, P or Si.

[0041] Straight chain, branched and cyclic alkyl groups having 1 to 20 carbon atoms; alkoxy groups having 1 to 20 carbon atoms; aryl groups having 6 to 60 carbon atoms; and alkyl groups having 1 to 20 carbon atoms containing heteroatoms may be substituted or unsubstituted. Substitution may be performed with one or more substituents selected from the group consisting of: deuterium, C1-C 20 Alkyl, C1-C 20 Alkoxy, C1-C 20 Alkylamine, C1-C 20 Alkylthienyl, C6-C 20 Arylthienyl, C2-C 20 Alkenyl, C2-C 20 Alkynyl, C3-C20 Cycloalkyl, C6-C 60 Aryl, deuterated C6-C 60 Aryl, C8-C 20 an aryl group, ... 20 A heterocyclic group, but the substituents are not limited to these substituents.

[0042] The amount of the organic silane compound may be 0.2 mole to 50 moles per mole of the titanium atom of the main catalyst, but is not limited thereto.

[0043] For example, during the polymerization of ultra-high molecular weight polyethylene, the polymerization reaction can be carried out at 1 kg / cm 2 G to 60kg / cm 2 The pressure conditions of G and the temperature conditions of 60°C to 95°C are carried out for a residence time of the reactants of 1 hour to 4 hours.

[0044] The polymerization activity of the ultra-high molecular weight polyethylene according to another embodiment may be 5 kg-PE / g-catalyst to 40 kg-PE / g-catalyst, so that the polymerization reaction can be easily controlled. In addition, the viscosity average molecular weight of the ultra-high molecular weight polyethylene is 2.0×10 6 g / ml to 10.0×10 6 g / ml, a bulk density of 0.30 g / ml to 0.50 g / ml, an average particle size of 100 μm to 150 μm, and an agglomeration of particles of 1 μm or more is 8.0 wt% or less. It can be easily used for UHMWPE processing.

[0045] Example 1

[0046] Preparation of solid catalyst for producing ultra-high molecular weight polyethylene

[0047] Step 1: Preparation of magnesium halide alcohol adduct solution

[0048] After replacing a 1L reactor equipped with a mechanical stirrer with a nitrogen atmosphere, 20 g of solid magnesium dichloride (MgCl2), 200 ml of toluene and 120 ml of n-butanol were added and stirred at 350 rpm. The temperature was raised to 65°C for 1 hour and then maintained for 2 hours to obtain a uniform solution of the magnesium halide alcohol adduct fully dissolved in the solvent.

[0049] Step 2: Preparation of magnesium halide support

[0050] After the temperature of the solution prepared in the first step was cooled to 20°C, 20 ml of TiCl4 was slowly injected over 40 minutes (0.5 ml / min). After that, 62.5 ml of TiCl4 was injected more quickly over 100 minutes (0.625 ml / min). At this time, the temperature of the reactor was carefully maintained not to rise above 25°C.

[0051] When the injection was complete, the temperature of the reactor was raised to 60°C for 1 hour and maintained for another 1 hour.

[0052] When all the processes were completed, the reactor was left to stand to completely settle the solid components. The supernatant was removed, and then the solid components in the reactor were washed once with 300 ml of toluene and precipitated to completely remove impurities in the liquid phase to obtain a clean magnesium chloride carrier in the form of a solid.

[0053] Step 3: Preparation of catalyst loaded with titanium and dimethyl phthalate

[0054] 200 ml of toluene was added to the magnesium chloride support, and the mixture was maintained at 25°C while stirring at 250 rpm. After that, 30 ml of TiCl4 was injected at a time and maintained for 1 hour for primary reaction. Thereafter, 2 ml of dimethyl phthalate was injected, and the temperature of the reactor was raised to 60°C and maintained for 1 hour to allow secondary reaction between TiCl4 and the support to occur.

[0055] When all the processes were completed, the reactor was left to stand to completely settle the solid components, and then the supernatant was removed. The prepared solid catalyst was washed once with 200 ml of toluene and 6 times with 200 ml of hexane, and precipitated to remove impurities.

[0056] Polymerization of ultra-high molecular weight polyethylene

[0057] Ethylene was continuously flowed into a continuous polymerization reactor having a volume of 4 liters, and the interior was filled with ethylene. A hexane dilution of the organic aluminum mixture was prepared so that it might become 0.5 M triisobutylaluminum and 0.5 M triethylaluminum. A 1.0 M titanium catalyst hexane dilution solution and a 1.0 M organic silane dilution solution were prepared separately in different boxes.

[0058] While maintaining the reactor temperature at 80°C, the organic aluminum diluent, catalyst diluent, and organic silane diluent were injected at a constant rate to make Ti:TEAl:TIBA:Si=1:0.5:0.5:5. Hexane was continuously injected to make the total amount of hexane slurry in the reactor 2 liters. The internal pressure of the reactor was maintained at 5 kg / cm 2 G, and the residence time was maintained at 2 hours. The hexane slurry discharged from the reactor was filtered and dried to obtain ultra-high molecular weight polyethylene particles.

[0059] Example 2

[0060] An ultra-high molecular weight polyethylene was prepared in the same manner as in Example 1, except that during the polymerization in Example 1, triisobutylaluminum was changed to 0.25 mmol and triethylaluminum was changed to 0.75 mmol.

[0061] Example 3

[0062] An ultra-high molecular weight polyethylene was prepared in the same manner as in Example 1, except that during the polymerization in Example 1, triisobutylaluminum was changed to 0.75 mmol and triethylaluminum was changed to 0.25 mmol.

[0063] Example 4

[0064] An ultra-high molecular weight polyethylene was prepared in the same manner as in Example 1, except that during the polymerization in Example 1, triisobutylaluminum was changed to 1 mmol and triethylaluminum was changed to 1 mmol.

[0065] Example 5

[0066] An ultra-high molecular weight polyethylene was prepared in the same manner as in Example 1, except that during the polymerization in Example 1, triisobutylaluminum was changed to 0.25 mmol and triethylaluminum was changed to 0.25 mmol.

[0067] Comparative Example 1

[0068] An ultra-high molecular weight polyethylene was prepared in the same manner as in Example 1, except that during the polymerization in Example 1, triisobutylaluminum was changed to 0 mmol and triethylaluminum was changed to 1 mmol.

[0069] Comparative Example 2

[0070] An ultra-high molecular weight polyethylene was prepared in the same manner as in Example 1, except that during the polymerization in Example 1, triisobutylaluminum was changed to 1 mmol and triethylaluminum was changed to 0 mmol.

[0071] Comparative Example 3

[0072] An ultra-high molecular weight polyethylene was prepared in the same manner as in Example 1, except that dicyclopentyldimethoxysilane was not added during the polymerization in Example 1.

[0073] The above Examples 1 to 5 and Comparative Examples 1 to 3 are summarized in the following Table 1 based on the contents of triisobutylaluminum and triethylaluminum.

[0074] [Table 1]

[0075]

[0076] <Measurement and evaluation items of physical properties and their test methods>

[0077] Table 2 shows the measurement results of physical properties of the ultra-high molecular weight polyethylene polymers prepared in Examples 1 to 5 and Comparative Examples 1 to 3 above.

[0078] Polymerization activity (kg-PE / g-catalyst)

[0079] The polymerization activity (kg-PE / g-catalyst) was calculated as the weight ratio of polymer produced per the amount of catalyst used.

[0080] Bulk density (g / ml)

[0081] Bulk density is measured according to ASTM D1895-96.

[0082] Viscosity average molecular weight (×10 6 g / ml)

[0083] The molecular weight (Mv) of the polymer is calculated by measuring the intrinsic viscosity and using the Margolies equation.

[0084] In particular, molecular weight (Mw) is calculated from intrinsic viscosity [η] according to ASTM D 4020. In the case of polymers, viscosity can provide useful information of the solution phase at dilute concentrations. The value obtained by dividing the viscosity of the polymer by the viscosity and concentration of the solution is called specific viscosity. When the concentration of the polymer becomes zero, the extrapolated value of the specific viscosity is defined as intrinsic viscosity (IV). Linear polymers have a high correlation with molecular weight because the IV value is mainly affected by the size of the polymer. In the case of ultra-high molecular weight polyethylene, the Margolies equation is widely used.

[0085] Mw=5.37×104×[η]1.49

[0086] Mw = average molecular weight (g / mol)

[0087] [η] = intrinsic viscosity (dl / g)

[0088] Average particle size (μm)

[0089] The particle size distribution of the polymer was measured using a laser particle analyzer (Mastersizer X, Malvern Instruments). As a result, the average particle size was expressed as D (v, 0.5), and the particle size distribution was expressed as (D (v, 0.9) - D (v, 0.1)) / D (v, 0.5).

[0090] Here, D(v,0.5) represents the median size of particles contained in the sample, and D(v,0.9) and D(v,0.1) represent the particle sizes at 90% and 10% of the particle size distribution standard, respectively. The smaller the value of the particle size distribution, the narrower the particle size distribution.

[0091] Aggregation of particles 1 μm or larger (wt%)

[0092] For the aggregation of polymer particles, the amount of aggregated particles relative to the total weight was measured using a metal sieve having 1 μm openings.

[0093] [Table 2]

[0094]

[0095] As shown in Table 2, it can be seen that the ultra-high molecular weight polyethylene polymerized by the method of Example 1 has high activity, high bulk density and high molecular weight, and shows a very low level of large particle aggregation.

[0096] Depending on the mixing ratio of the added organoaluminum co-catalyst, a rapid decrease in activity or a rapid decrease in molecular weight was observed, indicating that there is an optimum value for the organoaluminum mixing ratio.

[0097] Through Examples 4 and 5, when the total amount of organoaluminum increases, the molecular weight decreases rapidly, and when the total amount of organoaluminum decreases, the activation of the catalyst is inhibited, making the activity very low, and particle agglomeration increases rapidly.

[0098] Furthermore, for a single organoaluminum cocatalyst as in Comparative Examples 1 and 2, Comparative Example 1 showed a very low molecular weight and Comparative Example 2 showed very low activity and large particle agglomeration.

[0099] Furthermore, as in Comparative Example 3, even when a mixture of organoaluminum co-catalysts was used at an appropriate ratio, polymerization with a very low molecular weight was confirmed without an external organosilane donor.

[0100] According to Table 2, in the polymerization of ultra-high molecular weight polyethylene, in order to obtain ultra-high molecular weight polyethylene having high activity, high molecular weight and high bulk density with less particle aggregation, the main catalyst, organoaluminum co-catalyst and external organosilane donor must be properly combined.

[0101] As described above, the present disclosure provides a method for obtaining ultra-high molecular weight polyethylene particles having high activity, high bulk density and high molecular weight while exhibiting low particle agglomeration by introducing and polymerizing a main catalyst, a co-catalyst mixed with two or more types of organoaluminum, and an organosilane external electron donor together in a reactor in the polymerization of ultra-high molecular weight polyethylene.

[0102] The above description is merely an illustration of the technical spirit of the present disclosure, and those skilled in the art to which the present disclosure belongs may make various modifications and changes without departing from the essential attributes of the present disclosure. In addition, the embodiments of the present invention are not intended to limit the technical spirit of the present disclosure, but to explain the technical spirit of the present disclosure, and therefore the scope of the technical spirit is not limited by these embodiments. The scope of protection of the present disclosure shall be interpreted by the following claims, and all technical ideas within the scope equivalent to the claims shall be interpreted as being included within the scope of the present disclosure.

Claims

1. A method for polymerizing ultra-high molecular weight polyethylene, the method comprising: reacting a main catalyst containing a titanium active site, an organoaluminum cocatalyst mixed with two or more types of organoaluminums, and an organosilane compound to polymerize the ultra-high molecular weight polyethylene, wherein the organoaluminum co-catalyst used for polymerizing the ultra-high molecular weight polyethylene comprises a mixture of two or more having a structure represented by AlRnX3-n, wherein n is 1 to 3, R is a straight or branched alkyl group having 1 to 8 carbon atoms, and X is a halogen atom or a hydrogen atom, wherein the amount of the organoaluminum co-catalyst is 0.1 mol to 100 mol of aluminum atoms of the co-catalyst per mol of titanium atoms of the main catalyst, and The two or more organic aluminums of the mixture are mixed in a molar ratio of 1:1 or 1:

3.

2. The method for polymerizing ultra-high molecular weight polyethylene according to claim 1, wherein the halogen atom is F, Cl and Br.

3. The method for polymerizing ultra-high molecular weight polyethylene according to claim 1, wherein the main catalyst is a Ziegler-Natta catalyst in which titanium is supported on magnesium dichloride (MgCl2).

4. The method for polymerizing ultra-high molecular weight polyethylene according to claim 3, wherein the procatalyst is prepared by the following method comprising the steps of: The first step is to prepare a magnesium compound solution by reacting the magnesium dichloride (MgCl2) with an alcohol; The second step: preparing a precursor by reacting the magnesium compound solution with titanium tetrachloride; and The third step: preparing a catalyst by subjecting the precursor to a primary reaction with titanium tetrachloride, and then reacting the resultant with a diester compound represented by the following formula 1; [Formula 1] R1OOCR2COOR3 wherein R1 and R3 are straight or branched chain alkyl groups having 1 to 10 carbon atoms, and R2 is a hydrocarbon having 1 to 20 carbon atoms.

5. The method for polymerizing ultra-high molecular weight polyethylene according to claim 1, wherein a solvent for polymerizing the ultra-high molecular weight polyethylene is one of linear, branched and cyclic saturated hydrocarbons.

6. The method for polymerizing ultra-high molecular weight polyethylene according to claim 1, wherein the organosilane compound used for polymerizing the ultra-high molecular weight polyethylene is a compound represented by the following Formula 2: [Formula 2] wherein R4, R5, R6 and R7 are each independently a straight chain, branched or cyclic alkyl group having 1 to 20 carbon atoms; an alkoxy group having 1 to 20 carbon atoms; an aryl group having 6 to 20 carbon atoms; and an alkyl group having 1 to 20 carbon atoms containing a heteroatom.

7. The method for polymerizing ultra-high molecular weight polyethylene according to claim 6, wherein the amount of the organosilane compound is 0.2 mol to 50 mol per mol of the titanium atom of the main catalyst.

8. The method for polymerizing ultra-high molecular weight polyethylene according to claim 1, wherein the polymerization reaction during the polymerization of the ultra-high molecular weight polyethylene is carried out at a temperature of 1 kg / cm 2 G to 60kg / cm 2 The pressure conditions of G and the temperature conditions of 60°C to 95°C are carried out for a reactant residence time of 1 hour to 4 hours.

9. A method for preparing a procatalyst for ultra-high molecular weight polyethylene polymerization, the method being carried out by reacting a procatalyst comprising titanium active sites, an organoaluminum cocatalyst mixed with two or more types of organoaluminum, and an organosilane compound, the method comprising: The first step is to prepare a magnesium compound solution by reacting the magnesium dichloride (MgCl2) with an alcohol; The second step: preparing a precursor by reacting the magnesium compound solution with titanium tetrachloride; and The third step: preparing a catalyst by subjecting the precursor to a primary reaction with titanium tetrachloride, and then reacting the resultant with a diester compound represented by the following formula 1; [Formula 1] R1OOCR2COOR3 wherein R1 and R3 are straight or branched alkyl groups having 1 to 10 carbon atoms, and R2 is a hydrocarbon group having 1 to 20 carbon atoms, wherein the organoaluminum co-catalyst used for polymerizing the ultra-high molecular weight polyethylene comprises a mixture of two or more having a structure represented by AlRnX3-n, wherein n is 1 to 3, R is a straight or branched alkyl group having 1 to 8 carbon atoms, and X is a halogen atom or a hydrogen atom, wherein the amount of the organoaluminum co-catalyst is 0.1 mol to 100 mol of aluminum atoms of the co-catalyst per mol of titanium atoms of the main catalyst, and The two or more organic aluminums of the mixture are mixed in a molar ratio of 1:1 or 1:

3.

10. The method according to claim 9, wherein the halogen atoms are F, Cl and Br.

11. An ultra-high molecular weight polyethylene, prepared according to the method according to any one of claims 1 to 8 or using a main catalyst prepared according to the method according to any one of claims 9 to 10, wherein the polymerization activity of the ultra-high molecular weight polyethylene is 5 kg-PE / g-catalyst to 40 kg-PE / g-catalyst, and the viscosity average molecular weight is 2.0×10 6 g / ml to 10.0×10 6 g / ml, a bulk density of 0.30 g / ml to 0.50 g / ml, an aggregation of particles of 1 μm or more is 8.0 wt% or less, and an average particle size of 100 μm to 150 μm.

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