KR20130057217A - A catalyst for preparation of ultra high molecular weight polyethylene and a preparation method of ultra high molecular weight polyethylene using the same - Google Patents

Abstract

PURPOSE: A catalyst for manufacturing high molecular weight polyethylene is provided to have excellent catalyst activity through a simple manufacturing process and to manufacture a solid complex titanium catalyst with a controlled particle shape. CONSTITUTION: A catalyst for manufacturing high molecular weight polyethylene is manufactured by a step of preparing a support by conduct a reaction of magnesium alkoxide compound and organic aluminum compound; and a step of conduct a reaction of the support and titanium compound. A manufacturing method of a ultrahigh molecular weight polyethylene comprises a step of polymerizing ethylene under the presence of the solid complex titanium catalyst and organic metal compound. The organic metal compound is an organic aluminum compound.

Description

Catalyst for Preparation of Ultra High Molecular Weight Polyethylene and A Preparation Method of Ultra High Molecular Weight Polyethylene Using the Same

The present invention relates to a novel titanium solid complex catalyst supported on a support comprising magnesium and to a method for producing ultra high molecular weight polyethylene using the same, which is used in the production of ultra high molecular weight polyethylene.

Ultra high molecular weight polyethylene is a kind of polyethylene resin, which refers to polyethylene having a molecular weight of at least 10 ⁶ g / mol or more, and according to ASTM 4020, "it is contained 0.05% in 100 ml of decahydronaphthalene solution and has a relative viscosity of 2.30 or more at 135 ° C. Linear polyethylene having a value ". Ultra high molecular weight polyethylene has much higher molecular weight than general-purpose polyethylene, so it has excellent characteristics such as rigidity, abrasion resistance, environmental stress uniformity, self lubrication, chemical resistance and electrical properties. Due to such excellent properties, ultra high molecular weight polyethylene can be said to be a high quality special material obtained from general purpose raw materials.

Ultra-high molecular weight polyethylene produced through the polymerization process has a high molecular weight and cannot be pelletized like general purpose polyethylene, so it is produced and sold as a powder. Therefore, it is difficult to melt processing, which is a conventional polyethylene processing method. It should be excellent, and in terms of solubility, the particle size and particle size distribution of the ultra high molecular weight polyethylene powder are the main characteristics. This is because dissolution characteristics may be impaired when the particle size distribution is large even when the particles are too large or small. Therefore, in the case of a catalyst for producing ultra high molecular weight polyethylene, the particle size, particle size distribution and presence of fine particles of the polymer obtained as a result of the polymerization process using the catalyst are important characteristics of the catalyst.

Catalysts for the production of ultra high molecular weight polyethylene and catalysts based on titanium have been reported. US Patent No. 4,962,167 discloses a catalyst preparation process obtained by reacting a reactant of a magnesium halide compound with a titanium alkoxide compound and a reactant of an aluminum halide and a silicon alkoxide compound. The catalyst thus prepared provides a relatively high apparent density, but there is still a need for improvement, and there is also room for improvement in the activity of the catalyst.

U.S. Patent 5,587,440 reports a method of preparing a polymer having a narrow particle distribution and a high apparent density by reducing the titanium (IV) halide to an organoaluminum compound and then subjecting it to an organoaluminum compound. It has a relatively low disadvantage.

As described above, while the production process is simple, high polymerization activity, the catalyst particles are controlled, and in particular, since the particle distribution of the polymer is narrow, development of a new ultra high molecular weight polyethylene production catalyst having fewer large particles or fine particles is required.

An object of the present invention is to provide a new catalyst solid component for preparing ultra-high molecular weight polyethylene, which is excellent in catalytic activity from a low-cost compound through a simple manufacturing process, and has a small particle size distribution of the polymerized polymer, and thus has less large particles or fine particles. .

Specifically, it is also an object of the present invention to provide a method for producing a catalyst for ultra-high molecular weight polyethylene production in which the form of the catalyst particles is controlled and the particle distribution of the polymer is narrow and there are few large particles and fine particles.

It is another object of the present invention to provide a method for producing ultra high molecular weight polyethylene using the catalyst of the present invention.

Other objects and benefits of the present invention will become more apparent with reference to the following description and claims of the present invention.

The catalyst for preparing ultra-high molecular weight polyethylene having a small particle distribution of the polymer to be provided by the present invention having a small particle size and a small particle is characterized by being manufactured by a manufacturing method comprising the following steps:

(1) reacting a magnesium alkoxide compound with an organoaluminum compound of formula (I) or (II) to prepare a carrier,

R _a AlX _b ‥‥‥ (I)

Where R is hydrogen or an alkyl, alkoxy, haloalkyl or aryl group having 1 to 10 carbon atoms, X is a halogen atom such as chlorine, bromine, iodine or fluorine, a and b are natural numbers and a + b = 3 Or)

R _a Al ₂ X _b ‥‥‥ (II)

(Where R is hydrogen or an alkyl, alkoxy, haloalkyl or aryl group having 1 to 10 carbon atoms, X is a halogen atom such as chlorine, bromine, iodine, fluorine, a and b are natural numbers, a + b = 6 to be); And

(2) reacting the carrier prepared in step (1) with a titanium compound represented by the following general formula (1) 'or (2),

(WR _n ) (WR ' _m ) TiQ _x ‥‥‥ (One)

(W is a cyclopentadienyl, indenyl or fluorenyl group, R and R 'are each independently hydrogen, alkyl, alkylether, allylether, and Q is alkyl, allyl, arylalkyl). Represents an amide, alkoxy or halogen atom, n is 0 ≦ n <5, m is 0 ≦ m <5, x is a x integer that satisfies 1 ≦ x ≦ 4) or

_{(C 5 H 5 -y- x R} x) (R 'y) TiQ p  ‥‥‥ (2)

Wherein R is hydrogen or an alkyl radical having 1 to 20 carbon atoms, R 'is an alkyl or alkoxy group having 1 to 20 carbon atoms or a halogen atom, and Q represents an alkyl, allyl, arylalkyl, amide, alkoxy or halogen atom x is 0.1, 2, 3, 4, or 5, y is 0 or 1, and p is an integer that satisfies 1 ≦ p ≦ 4).

Examples of the magnesium alkoxide compound used in the above step (1) include magnesium methoxide, magnesium ethoxide, magnesium propoxide, magnesium butoxide and the like. Two or more of the magnesium alkoxide compounds may be used as a mixture, and the most preferable type is magnesium ethoxide.

Magnesium alkoxide may be prepared with reference to patents such as Korean Patent Publication No. 2010-007076, Publication No. 2009-0071718, and Korean Patent Registration No. 00807895. Magnesium alkoxide prepared as described above has a spherical shape, and can control particle size and particle size distribution, and the catalyst for preparing ultra-high molecular weight polyethylene having a small particle size distribution of the polymer to be provided by the present invention has a small number of large particles or fine particles. It can be used as a precursor of the carrier.

In step (1), the magnesium alkoxide prepared as described above is reacted with the organoaluminum compound of formula (I) or (II) to prepare a magnesium compound carrier:

R _a AlX _b ‥‥‥ (I)

Where R is hydrogen or an alkyl, alkoxy, haloalkyl or aryl group having 1 to 10 carbon atoms, X is a halogen atom such as chlorine, bromine, iodine or fluorine, a and b are natural numbers and a + b = 3 Or)

R _a Al ₂ X _b ‥‥‥ (II)

(Where R is hydrogen or an alkyl, alkoxy, haloalkyl or aryl group having 1 to 10 carbon atoms, X is a halogen atom such as chlorine, bromine, iodine, fluorine, a and b are natural numbers, a + b = 6 to be).

The amount of the organoaluminum compound used in the reaction of step (1) is preferably injected at a rate of 0.05 to 30 moles, preferably 0.5 to 10 moles per mole of magnesium magnesium alkoxide compound. When the organoaluminum compound is used at less than 0.05 mole, it is difficult to obtain a desired effect. When the organoaluminum compound is used at less than 30 mole, the activity of the catalyst is sharply lowered or the shape of the catalyst is destroyed. In addition, since the form of the catalyst changes greatly depending on the reaction temperature, it is preferable to carry out at a sufficiently low temperature. It is advantageously carried out at -50 ° C to 80 ° C, more preferably at -20 ° C to 50 ° C. After the contact reaction, the reaction temperature was gradually raised to react at room temperature (25 ° C.) to 150 ° C. for 0.5 to 5 hours.

In the step (2), the titanium compound represented by the following general formula (1) or (2) is added to the magnesium compound carrier prepared in step (1), and the temperature is increased to prepare a solid particle catalyst.

(WR _n ) (WR ' _m ) TiQ _x ‥‥‥ (One)

 (W is a cyclopentadienyl, indenyl or fluorenyl group, R and R 'are each independently hydrogen, alkyl, alkylether, allylether, and Q is alkyl, allyl, arylalkyl). Represents an amide, alkoxy or halogen atom, n is 0 ≦ n <5, m is 0 ≦ m <5, and x is 1 ≦ x ≦ 4

_{(C 5 H 5 -y- x R} x) (R 'y) TiQ p  ‥‥‥ (2)

Where R is hydrogen or an alkyl radical of 1 to 20 carbon atoms, and R 'is of 1 to 20 carbon atoms An alkyl group or an alkoxy group or a halogen atom, Q represents an alkyl, allyl, arylalkyl, amide, alkoxy or halogen atom, x is 0.1, 2, 3, 4 or 5 and y is 0 or 1 P is an integer satisfying 1 ≦ p ≦ 4).

Examples of the titanium compound that satisfies the general formula (1) or (2) include, for example, Cp ₂ TiCl ₂ , (Me ₅ Cp) ₂ TiCl ₂ (where Me is methyl, Cp is pentadienyl, the same below), (Me ₄ Cp) ₂ TiCl ₂ , (n-BuCp) ₂ TiCl ₂ (where n-Bu is the same as butyl, hereinafter), (i-PrCp) ₂ TiCl ₂ (where i-Pr is isopropyl, hereinafter same) , Dicyclopentadienyl titanium compounds such as (EtCp) ₂ TiCl ₂ (where Et is ethyl, hereinafter), (indenyl) ₂ TiCl ₂ , and CpTiCl ₃ , (Me ₅ Cp) TiCl ₃ , (indenyl) Monocyclopentadienyl titanium compounds such as TiCl ₃ and the like. In addition, mixtures of the above titanium compounds can also be used in the present invention.

In the step (2), the reaction between the magnesium compound carrier and the titanium compound is carried out at an appropriate temperature to fix the titanium component to the magnesium compound carrier. At this time, the amount of the titanium compound used is preferably 0.001 mmol to 500 mmol, per mole of magnesium alkoxide compound, and preferably 0.01 mmol to 300 mmol. When the amount of the titanium compound is out of the above range, the activity of the catalyst is not large compared to the amount of the catalyst used, so the efficiency of using the catalyst is inferior. Preferably, the reaction of step (2) is preferably carried out at 0 ° C. to 120 ° C., and more preferably at 30 ° C. to 110 ° C. for 0.5 hours to 5 hours. After the reaction, the liquid mixture is separated, washed with hexane and dried to obtain a catalyst.

The catalyst prepared by the process presented in the present invention is used for the polymerization and copolymerization of ethylene to produce ultra high molecular weight polyethylene.

Ultrahigh molecular weight polyethylene polymerization in the presence of the catalyst of the present invention is a catalyst system comprising (i) a solid complex titanium catalyst according to the invention consisting of magnesium, titanium and halogen, and (ii) an organometallic compound of Group II or III of the periodic table. Is performed using

The solid complex titanium catalyst component of the present invention may be prepolymerized with ethylene or α-olefin before being used as a component in the polymerization reaction. Prepolymerization can be carried out in the presence of a hydrocarbon solvent such as hexane and at the sufficiently low temperature and ethylene or α-olefin pressure conditions in the presence of the above catalyst component and an organoaluminum compound such as triethylaluminum. Prepolymerization helps to improve the shape of the polymer after polymerization by surrounding the catalyst particles with a polymer to maintain the catalyst shape. The weight ratio of polymer / catalyst after prepolymerization is usually from 0.1: 1 to 60: 1.

The organometallic compound beneficial in the present invention may be represented by the general formula of MR _n , wherein M is a periodic table group II or IIIA metal component such as magnesium, calcium, zinc, boron, aluminum, gallium, and R is methyl, An alkyl group having 1 to 20 carbon atoms, such as ethyl, butyl, hexyl, octyl and decyl, n represents the valence of the metal component. As a more preferable organometallic compound, trialkylaluminum having an alkyl group having 1 to 6 carbon atoms such as triethylaluminum and triisobutylaluminum or a mixture thereof is advantageous. In some cases, an organoaluminum compound having one or more halogen or hydride groups such as ethylaluminum dichloride, diethylaluminum chloride, ethylaluminum sesquichloride, diisobutylaluminum hydride may be used.

The polymerization reaction can be carried out by gas phase or bulk polymerization in the absence of an organic solvent, or by liquid phase slurry polymerization in the presence of an organic solvent. These polymerization methods are carried out in the absence of oxygen, water and other compounds that can act as catalyst poisons. In the case of liquid phase slurry polymerization, the preferred concentration of the solid complex titanium catalyst on the polymerization reaction system is about 0.001 to 5 millimoles, preferably about 0.001 to 0.5 millimoles, of titanium atoms of the catalyst per 1 liter of solvent. Solvents include alkanes or cycloalkanes such as pentane, hexane, heptane, n-octane, isooctane, cyclohexane, methylcyclohexane, toluene, xylene, ethylbenzene, isopropylbenzene, ethyltoluene, n-propylbenzene, diethyl Alkylaromatics such as benzene, halogenated aromatics such as chlorobenzene, chloronaphthalene, ortho-dichlorobenzene, and mixtures thereof are advantageous. In the case of gas phase polymerization, the amount of the solid complex titanium catalyst is about 0.001 to 5 millimoles, preferably about 0.001 to 1.0 millimoles, and more preferably about 0.01 to 0.5 millimoles of titanium atoms of the catalyst per 1 liter of the polymerization zone. It is good. The preferred concentration of the organometallic compound (ii) is from about 1 to 2000 moles per mole of titanium atoms in the catalyst, calculated from metal atoms, more preferably from about 5 to 500 moles.

In order to obtain a high polymerization rate, the polymerization reaction is carried out at a sufficiently high temperature regardless of the polymerization process. Generally, about 20 to 200 ° C is suitable, and more preferably 20 to 95 ° C. As for the pressure of the monomer at the time of superposition | polymerization, atmospheric pressure-100 atmospheres are suitable, More preferably, the pressure of 2-50 atmospheres is suitable.

The product obtained in the polymerization method of the present invention is a solid ultra high molecular weight polyethylene homopolymer, has an intrinsic viscosity of 10 to 40 dl / g, an average particle size of 90 to 140 µm, and a high yield of the polymer, thus requiring removal of the catalyst residue. Rather, it has excellent apparent density and fluidity.

Hereinafter, the present invention will be described in more detail with reference to examples. However, these embodiments are for illustrative purposes only.  The invention is not limited to these examples.

Example  One

[Preparation of Solid Catalyst for Ultra High Molecular Weight Polyethylene Production]

The catalyst was prepared through the following two steps.

(1) Step: Magnesium Alkoxide Reaction of Compounds with Organoaluminum Compounds

A 1 L reactor equipped with a mechanical stirrer replaced with a nitrogen atmosphere was set at 5 ° C., and then 10 g of Mg (OEt) ₂ (spherical, average size of 17 microns, size distribution 1.2, see the laser particle analyzer description below) and 50 mL of hexane were added, and 300 rpm. 280 mL of diethylaluminum chloride (1.0M, hexane) solution was injected over 60 minutes with stirring. After the injection was completed, the reaction was carried out by maintaining at 5 ° C. for 30 minutes and then raising the temperature to 50 ° C. for 3 hours. After the reaction was completed, the temperature was lowered to room temperature, the stirrer was stopped, the carrier was allowed to settle, and the upper solution was removed. 200 mL of hexane was added to the slurry remaining in the reactor, and the mixture was washed three times by stirring, standing, and removing the supernatant. The carrier was then dried to yield 8.9 g of carrier.

(2) step: preparing the catalyst

10 mL of toluene was injected into the reactor at room temperature in 0.4 g of the carrier prepared in step (1), 100 micromole (μmol) of Cp ₂ TiCl ₂ per 1 g of the carrier was added to 5 mL of toluene, and the reaction was started with stirring. . After raising the temperature of the reactor to 60 ℃, it was maintained for 2 hours and then the temperature of the reactor was lowered to room temperature. After stirring was stopped, the precipitate was allowed to settle and the supernatant was separated. The prepared catalyst slurry was washed four times with 20 mL of purified toluene. After washing, the catalyst was vacuum dried to prepare the final solid catalyst.

[polymerization]

The high-pressure reactor with a capacity of 2 liters was dried in an oven and assembled in a hot state, and then nitrogen and vacuum were operated three times in alternation to make the reactor into a nitrogen atmosphere. 1000 ml of n-hexane was injected into the reactor, followed by 1 mmol of triisobutylaluminum. The temperature of the reactor was raised to 80 ° C. while stirring at 700 rpm with a stirrer, the ethylene pressure was adjusted to 200 psig, and then 25 mg of the solid catalyst prepared above was injected, and polymerization was performed for one hour. After completion of the polymerization, the temperature of the reactor was lowered to room temperature, and excess ethanol solution was added to the polymerization contents. The resulting polymer was collected separately and dried in a vacuum oven at 50 ^{° C.} for at least 6 hours to obtain a white powdery ultra high molecular weight polyethylene.

The particle size and particle size distribution of the carrier and polymer were measured using a laser particle analyzer (Mastersizer X, Malvern Instruments) .The particle size was average size D (v, 0.5) and the particle size distribution was (D (v, 0.9) ) -D (v, 0.1)) / D (v, 0.5), where D (v, 0.5) represents the particle size represented by 50% of the sample, and D (v, 0.9) and D (v, 0.1) indicates the particle size indicated by 90% and 10% of the samples, respectively. The smaller the particle size distribution, the narrower the distribution. The composition of the catalyst was analyzed by ICP. The polymerization results are shown in Table 1 together with the apparent density (g / ml) of the polymer. The relative viscosity of the polymer was calculated by measuring the viscosity by melting the polymer using a decahydronaphthalene solvent according to ISO 1628 Part3. From this the average molecular weight (Mv) was calculated using Margolie's equation (Mv = 5.34 x 10 ⁴ x [η] ^1.49 , Mv = viscosity average molecular weight, η = intrinsic viscosity) well known in the art.

Example  2

In step (2) of Example 1, Cp ₂ TiCl ₂ A catalyst was prepared under the same conditions as in Example 1 except that (t-BuCp) ₂ TiCl ₂ was used, and polymerization was carried out in the same manner using the obtained catalyst. The results are summarized in Table 1.

Example  3

In step (2) of Example 1, a catalyst was prepared under the same conditions as in Example 1 except that (i-PrCp) ₂ TiCl ₂ was used instead of Cp ₂ TiCl ₂ , and the polymerization was carried out in the same manner using the obtained catalyst. Was carried out. The results are summarized in Table 1.

Example  4

In Step (2) of Example 1, a catalyst was prepared under the same conditions as in Example 1, except that (Me ₅ Cp) (2,6-i-Prphenoxy) TiCl ₂ was used instead of Cp ₂ TiCl _2. And superposition | polymerization was similarly performed using the obtained catalyst. The results are summarized in Table 1.

Example  5

In step (2) of Example 1, a catalyst was prepared under the same conditions as in Example 1 except that CpTiCl ₃ was used instead of Cp ₂ TiCl ₂ , and polymerization was carried out in the same manner using the obtained catalyst. The results are summarized in Table 1.

Example  6

In step (2) of Example 1, a catalyst was prepared under the same conditions as in Example 1, except that (Me ₅ Cp) TiCl ₃ was used instead of Cp ₂ TiCl ₂ , and polymerization was carried out in the same manner using the obtained catalyst. Was carried out. The results are summarized in Table 1.

Example  7

In step (2) of Example 1, a catalyst was prepared under the same conditions as in Example 1 except that (Indenyl) TiCl ₃ was used instead of Cp ₂ TiCl ₂ , and the polymerization was carried out in the same manner using the obtained catalyst. . The results are summarized in Table 1.

Comparative example  One

In Example 1, the step (1) of reacting the magnesium alkoxide compound with organoaluminum was omitted, and the catalyst was prepared under the same conditions as in Example 1 using the magnesium alkoxide compound as a carrier, and the same catalyst was used as the obtained catalyst. The polymerization was carried out. The results are summarized in Table 1.

Comparative example  2

(I)

95 g of MgCl ₂ and 4000 ml of toluene were added to a 1.0L reactor equipped with a mechanical stirrer, which was replaced with a nitrogen atmosphere, stirred at 300 rpm. Then, 620 ml of 2-ethylhexanol was added thereto, and the temperature was raised to 120 ° C. for 3 hours. Reacted. The magnesium homogeneous solution obtained after the reaction was cooled to 70 deg.

(Ii)

100.0 ml of silicon tetraethoxide was added to the magnesium solution cooled to 70 ° C. and reacted for 1 hour.

(Iii) step

The solution was adjusted to room temperature (25 ° C.) and 600 ml of titanium tetrachloride were added dropwise for 1 hour. After completion of the dropwise addition, 32 mL of diethylphthalate was added thereto, and the temperature of the reactor was raised to 70 ° C. over 1 hour, and maintained for 1 hour. After the stirring was stopped, the solution of the upper layer was separated, and then 3000 ml of toluene and 1000 ml of titanium tetrachloride were continuously injected into the remaining solid layer, and the temperature was raised to 100 ° C. and maintained for 2 hours. After the reaction, the reactor was cooled to room temperature, and washed with 4000 ml of hexane until unreacted free titanium tetrachloride was removed. The titanium content of the prepared solid catalyst was 3.5% by weight. The polymerization was carried out in the same manner as in Example 1 using the obtained catalyst, and the results are summarized in Table 1.

Comparative example  3

In step (ii) of Comparative Example 1, a catalyst was prepared under the same conditions as in Comparative Example 1, except that silicon tetraethoxide was not used and maintained for 1 hour, and polymerization was performed using the obtained catalyst in the same manner. It was. The results are summarized in Table 1.

Example activation
(kg-PE / mol-Ti / atm / hr) surface
density
(g / ml) Average
Molecular Weight (g / mol)
(x 10 ⁶ ) polymer
Average particle
size
(Μm) Particle size
Distribution
(span ratio) One 1530 0.36 3.05 111.3 0.87 2 1670 0.35 3.80 111.9 0.85 3 780 0.35 2.81 97.1 0.85 4 1950 0.35 3.73 112.4 0.84 5 3970 0.35 3.26 120.9 0.79 6 980 0.34 3.23 102.5 0.85 7 6900 0.36 4.57 132.2 0.93 Comparative Example 1 210 - 0.65 - - Comparative Example 2 5870 0.32 0.91 145.7 1.5 Comparative Example 3 6620 0.28 0.82 151.2 3.6

Claims (5)

Solid complex titanium catalyst for preparing ultra high molecular weight polyethylene prepared according to the method comprising the following steps:
(1) reacting a magnesium alkoxide compound with an organoaluminum compound of formula (I) or (II) to prepare a carrier,
R _a AlX _b ‥‥‥ (I)
(Where R is hydrogen or an alkyl, alkoxy, haloalkyl or aryl group having 1 to 10 carbon atoms, X is a halogen atom, a and b are natural numbers and a + b = 3) or
R _a Al ₂ X _b ‥‥‥ (II)
(Wherein R is hydrogen or an alkyl, alkoxy, haloalkyl or aryl group having 1 to 10 carbon atoms, X is a halogen atom, a and b are natural numbers and a + b = 6); And
(2) reacting the carrier prepared in step (1) with a titanium compound represented by the following general formula (1) or (2),
(WR _n ) (WR ' _m ) TiQ _x ‥‥‥ (One)
Wherein W is a cyclopentadienyl, indenyl or fluorenyl group, R and R 'are each independently hydrogen, alkyl, alkylether, allylether, Q is alkyl, allyl, arylalkyl, amide, alkoxy or halogen Represents an atom, n is 0 ≦ n <5, m is 0 ≦ m <5, and x is an integer satisfying 1 ≦ x ≦ 4) or
_{(C 5 H 5 -y- x R} x) (R 'y) TiQ p  ‥‥‥ (2)
Wherein R is hydrogen or an alkyl radical having 1 to 20 carbon atoms, R 'is an alkyl or alkoxy group having 1 to 20 carbon atoms or a halogen atom, and Q represents an alkyl, allyl, arylalkyl, amide, alkoxy or halogen atom , x is 0.1, 2, 3, 4 or 5 and y is 0 or 1). According to claim 1, wherein the organic aluminum compound used in step (1) is methyl aluminum dichloride, ethyl aluminum dichloride, propyl aluminum dichloride, butyl aluminum dichloride, ethyl aluminum sesquichloride, dimethyl aluminum chloride, di Solid complex titanium catalyst for producing ultra high molecular weight polyethylene, characterized in that the ethyl aluminum chloride, dipropyl aluminum chloride or dibutyl aluminum chloride. According to claim 1, wherein the titanium compound used in step (2), Cp ₂ TiCl ₂ , (Me ₅ Cp) ₂ TiCl ₂ , (Me ₄ Cp) ₂ TiCl ₂ , (n-BuCp) ₂ TiCl ₂ , (t-BuCp) ₂ TiCl ₂ , (i-PrCp) ₂ TiCl ₂ , (EtCp) ₂ TiCl ₂ , (Indenyl) ₂ TiCl ₂ , CpTiCl ₃ , (Me ₅ Cp) TiCl ₃ or (Indenyl) TiCl ₃ Solid complex titanium catalyst for ultra-high molecular weight polyethylene production, characterized in that.  A process for producing ultra high molecular weight polyethylene comprising polymerizing ethylene in the presence of a solid complex titanium catalyst and an organometallic compound according to claim 1. The method of claim 4, wherein the organometallic compound is an organoaluminum compound.