KR20110115016A - A catalyst for ultra high molecular weight polyethylene(uhmwpe) and production method of uhmwpe using the same - Google Patents

Abstract

The present invention relates to a catalyst for preparing ultra high molecular weight polyethylene and a method for producing ultra high molecular weight polyethylene using the same, comprising: (i) preparing a magnesium solution by bringing a magnesium halide compound into contact with an alcohol; (Ii) reacting the magnesium compound solution with a diester compound; And (iii) reacting the titanium compound with the reactant of the magnesium compound solution and the diester compound, the catalyst having a controlled particle shape and easily controlling the particle size, and the catalyst. The present invention relates to a method for producing ultra-high molecular weight polyethylene having a high apparent density, a polymer having an average particle size of 80 to 140 µm, and a narrow particle size distribution.

Description

A catalyst for producing ultra high molecular weight polyethylene and a method for producing ultra high molecular weight polyethylene using the same {A CATALYST FOR ULTRA HIGH MOLECULAR WEIGHT POLYETHYLENE (UHMWPE) AND PRODUCTION METHOD OF UHMWPE USING THE SAME}

The present invention relates to a catalyst for preparing ultra high molecular weight polyethylene and a polymerization method of ultra high molecular weight polyethylene using the same, and more particularly, to a solid complex titanium catalyst supported on a support containing magnesium for preparing ultra high molecular weight polyethylene, and using the catalyst The present invention relates to a method for producing ultra-high molecular weight polyethylene prepared by the present invention, which has a high apparent density and a narrow particle size distribution, and thus contains no large particles or fine particles.

Ultra high molecular weight polyethylene is a kind of polyethylene resin, and refers to polyethylene having a molecular weight of at least 10 ⁶ g / mol or more, and according to ASTM 4020, "the relative viscosity at 135 ° C is 2.30 to more than 100% in 100 ml of decahydronaphthalene solution. Linear polyethylene with " 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 is a large molecular weight and can not be pelletized like a general-purpose polyethylene, so it is produced and sold in powder form, the size and distribution of the powder is very important. In particular, the particle size distribution and the presence of microparticles of the polymer powder is an important characteristic. Appropriate size and distribution of the polymerized powder is characteristic of ultra high molecular weight polyethylene during processing, which is difficult to melt processing, which is a conventional polyethylene processing method, and can be regarded as a major characteristic in terms of ease in consideration of processing by dissolving in an appropriate solvent. This is because dissolution characteristics may be impaired when the particle distribution is large even if the particles are too large or small.

As such a catalyst for producing ultra high molecular weight polyethylene, a catalyst for producing an ultra high molecular weight polyethylene and a catalyst production process based on titanium has been reported. In particular, a catalyst production method using a magnesium compound solution is known to obtain the catalyst for olefin polymerization having a high apparent density.

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 together. The catalyst thus prepared provides a relatively high apparent density, but there are still improvements to be made, particularly in terms of catalyst activity.

U.S. Patent No. 5,587,440 discloses a method of preparing a polymer having a narrow particle size distribution and a high apparent density by reducing titanium (IV) halide to an organoaluminum compound and then subjecting it to an organoaluminum compound. There was a disadvantage of relatively low activity.

As described above, while the manufacturing process is simple, the high polymerization activity and the catalyst particles can be controlled to provide a high polymer apparent density, in particular the particle size distribution of the polymer produced is narrow, so that large particles or fine particles There is a need for development of new ultra high molecular weight polyethylene catalysts.

The object of the present invention is a new ultra-high molecular weight with a small number of large particles or fine particles due to a simple manufacturing process, excellent catalyst activity, the shape of the catalyst particles is controlled, the apparent density of the polymerized polymer, the particle size distribution of the polymer is narrow The present invention provides a catalyst for producing polyethylene and a method for producing the same.

Still another object of the present invention is to provide a method for producing ultra high molecular weight polyethylene using the catalyst for producing ultra high molecular weight polyethylene 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 ultrahigh molecular weight polyethylene production catalyst according to the invention is characterized in that it is prepared according to a process comprising the following steps:

(Iii) contacting the magnesium halide compound with an alcohol to prepare a magnesium compound solution;

(Ii) reacting the magnesium compound solution with a diester compound; And

(Iii) preparing a catalyst by reacting the titanium compound with the reactant of the magnesium compound solution and the diester compound.

In the step (i) of preparing the magnesium compound solution, the magnesium halide compound may be one or a mixture of two or more selected from the group below, or may be used in the form of a complex of these metals with other metals. May be: magnesium halides such as magnesium chloride, magnesium iodide, magnesium fluoride and magnesium bromide; Alkylmagnesium halides such as methylmagnesium halide, ethylmagnesium halide, propylmagnesium halide, butylmagnesium halide, isobutylmagnesium halide, hexylmagnesium halide, amylmagnesium halide and the like; Alkoxymagnesium halides such as methoxymagnesium halide, ethoxymagnesium halide, isopropoxymagnesium halide, butoxymagnesium halide and octoxymagnesium halide; And aryloxymagnesium halides such as phenoxyshimamium halide and methylphenoxymagnesium halide.

The compounds listed above may be represented by simple chemical formulas, but in some cases, they may not be represented by simple formulas depending on the method of preparing magnesium compounds. In this case, it can be regarded as a mixture of magnesium compounds listed generally. For example, a compound obtained by reacting a magnesium compound with a polysiloxane compound, a halogen-containing silane compound, an ester, an alcohol, or the like; Compounds obtained by reacting magnesium metal with an alcohol, phenol or ether in the presence of halo silane, phosphorus pentachloride, or thionyl chloride can also be used in the present invention. Preferred magnesium compounds are magnesium halides, in particular magnesium chloride, alkyl magnesium chloride, preferably having alkyl groups of C1 to C10, alkoxy magnesium chloride, preferably having alkoxy groups of C1 to C10, and aryloxy magnesium chloride, preferably Below, it has C6-C20 aryloxy group.

In the step (i) of preparing the magnesium compound solution, the magnesium compound solution may be prepared by contacting an alcohol to the magnesium compound in the presence or absence of a hydrocarbon solvent, preferably in the presence of a hydrocarbon solvent. do.

Alcohols used here include methanol, ethanol, propanol, butanol, pentanol, hexanol, octanol, decanol, dodecanol, octadecyl alcohol, benzyl alcohol, phenylethyl alcohol, isopropylbenzyl alcohol, cumyl alcohol, and the like. One or more alcohols having 1 to 20 carbon atoms may be used, and preferably, alcohols having 1 to 12 carbon atoms may be used.

In the preparation of the magnesium compound solution, the amount of alcohol used may vary depending on the average particle size and particle size distribution of the desired catalyst, but at least 0.5 mole, preferably about 1.0 mole to 20 mole, more preferably per mole of magnesium compound. Preferably from about 2.0 moles to 10 moles. When the amount of the alcohol is less than 0.5 mole, dissolution of the magnesium compound is difficult, and when the amount of the alcohol exceeds 20 mole, the amount of the titanium compound added to obtain the catalyst particles during the preparation of the catalyst becomes too large, and the particle size becomes difficult to control. .

In the preparation of the magnesium compound solution, the hydrocarbon solvent may include aliphatic hydrocarbons such as pentane, hexane, heptane, octane, decane and kerosene; Alicyclic hydrocarbons such as cyclopentane, methylcyclopentane, cyclohexane and methylcyclohexane; Aromatic hydrocarbons such as benzene, toluene, xylene, ethylbenzene, cumene and cymene; Halogenated hydrocarbons such as dichloropropane, dichloroethylene, trichloroethylene, carbon tetrachloride and chlorobenzene can be used.

In the step of preparing a magnesium compound solution, the reaction temperature during the contact reaction between the magnesium halide compound and the alcohol depends on the type and amount of the alcohol, but at least about -25 ° C, preferably -10 to 200 ° C, more preferably about It is 0-150 degreeC, reaction time is about 15 minutes-5 hours, Preferably it is about 30 minutes-4 hours.

In the step (ii) of reacting the magnesium compound solution with a diester compound used as an electron donor, the diester compound is a generic term for an organic compound having two ester groups, and is represented by the following general formula:

C ₆ H ₄ -1- [CO ₂ -R] -a- [CO ₂ -R '] ₂

(Wherein R and R 'are C1-C20 hydrocarbons, alkyl, isoalkyl, tertiaryalkyl, alkenyl, aryl, etc., may be the same or different, and a is a natural number of 2, 3 or 4).

Examples of the diester compound include dimethyl phthalate, diethyl phthalate, dipropyl phthalate, dibutyl phthalate, diisobutyl phthalate, dioctyl phthalate, diallyl phthalate, dicyclohexyl phthalate, benzyl butyl phthalate, diphenyl phthalate, and dimethyl isophthalate. , Diphenyl isophthalate, dimethyl terephthalate, dioctyl terephthalate, and the like, and other compounds satisfying the above general formula may be used.

The amount of the diester compound used is 0.5 to 0.01 mole per mole of magnesium halide compound, more preferably 0.2 to 0.05 mole is appropriate, the catalyst characteristics to be obtained in the present invention is most well represented in the above range.

In the step (ii) of reacting the magnesium compound solution with the diester compound, the reaction temperature is suitably 0 to 100 ° C., preferably 10 to 70 ° C. may be used.

In step (iii) of preparing the catalyst, catalyst particles are recrystallized by reacting the magnesium compound solution with a liquid titanium compound represented by the following general formula:

Ti (OR) _a X _4-a

(Wherein R is an alkyl group having 1 to 10 carbon atoms, X is a halogen atom and a is a natural number of 0 ≦ a ≦ 4).

Examples of the titanium compound satisfying the general formula include titanium tetrahalide such as TiCl ₄ , TiBr ₄ , and TiI ₄ ; _{Ti (OCH 3) Cl 3,} Ti (OC 2 H 5) Cl 3, Ti (OC 2 H 5) Br 3 and _{Ti (O (iC 4 H 9} ) three halogenated alkoxy titanium such as Br _3; Ti (OCH ₃ ) ₂ Cl ₂ , Ti (OC ₂ H ₅ ) ₂ Cl ₂ , dihalogenated alkoxytitanium titanium such as Ti (O (iC ₄ H ₉ ) ₂ Cl ₂ and Ti (OC ₂ H ₅ ) ₂ Br ₂ ; and Ti (OCH ₃ ) tetraalkoxytitaniums such as ₄ , Ti (OC ₂ H ₅ ) ₄ and Ti (OC ₄ H ₉ ) ₄ , which may be used alone or as a mixture in the catalyst preparation step. Compound, and a more preferable titanium compound is titanium tetrachloride.

The titanium compound is used to recrystallize the magnesium compound solution, the amount of the titanium compound is preferably 0.1 to 200 moles per mole of magnesium halide compound, preferably 0.1 to 100 moles, more preferably 0.2 to 80 moles to be.

The shape and size of the recrystallized solid component vary greatly depending on the reaction conditions when the magnesium compound solution and the titanium compound are brought into contact with each other. Therefore, the contact reaction between the magnesium compound solution and the titanium compound is preferably performed at a sufficiently low temperature, preferably, the contact reaction is performed at -70 to 70 ° C, more preferably at -50 to 50 ° C. After the contact reaction, the reaction temperature was gradually raised to fully react for 0.5 hours to 5 hours at 50 to 150 ° C.

The solid catalyst particles obtained in step (iii) can be further reacted with additional titanium compounds. The further titanium compound may be used alone or as a mixture of halogenated alkoxy titanium having 1 to 20 carbon atoms of titanium halide and alkoxy group, preferably halogenated alkoxy titanium having 1 to 8 carbon atoms of titanium halide and alkoxy group More preferably titanium tetrahalide is used.

The catalysts produced by the process according to the invention are suitable for the polymerization and copolymerization of ethylene for the production of ultra high molecular weight polyethylene, in particular homopolymerization of ethylene and ethylene and propylene, 1-butene, 1-pentene, 4-methyl-1-pentene, It is used for copolymerization with an α-olefin having 3 or more carbon atoms such as 1-hexene.

The polymerization reaction in the presence of the catalyst of the present invention comprises (i) a solid complex titanium catalyst according to the invention consisting of magnesium, titanium, a halogen atom and an electron donor, and (ii) an organometallic compound of Group II or III of the periodic table. It is carried out using a catalyst system.

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 helps to improve the shape of the polymer after polymerization by surrounding the catalyst particles with a polymer to maintain the catalyst shape. Prepolymerization can be carried out in the presence of a hydrocarbon solvent such as hexane, at sufficiently low temperatures and under conditions of ethylene or α-olefin pressure, in the presence of the catalyst component and an organoaluminum compound such as triethylaluminum. The weight ratio of polymer / catalyst after prepolymerization is usually from 0.1: 1 to 20: 1.

The general formula of the above (ii) organometallic compound is MR _n , where M is a periodic table group II or IIIA metal component such as magnesium, calcium, zinc, boron, aluminum, gallium, and R is methyl, ethyl, butyl, hexyl C1-C20 alkyl groups, such as, octyl, and decyl, are represented, and n represents the valence of a metal component. As said organometallic compound, trialkylaluminum which has C1-C6 alkyl groups like triethylaluminum and triisobutylaluminum, and a mixture thereof are advantageous. In some cases, organoaluminum compounds having one or more halogen atoms or hydride groups may be used, such as ethylaluminum dichloride, diethylaluminum chloride, ethylaluminum sesquichloride and diisobutylaluminum hydride. The concentration of the (ii) organometallic compound is about 1 to 2000 moles, more preferably about 5 to 500 moles per mole of titanium atoms in the catalyst (i), calculated from the metal atoms in the organometallic compound.

The polymerization reaction using the catalyst of the present invention can be carried out by a gas phase or bulk polymerization method in the absence of an organic solvent or a liquid slurry polymerization method in the presence of an organic solvent. The polymerization process is carried out in the absence of oxygen, water and other compounds that can act as catalyst poisons. In the case of gas phase polymerization, the amount of the (i) solid complex titanium catalyst is about 0.001 to 5 millimoles, preferably about 0.001 to 1.0 millimoles, more preferably about 0.01 to 0.5 millimoles of titanium atoms of the catalyst per liter of the polymerization zone. It is good. In the case of liquid phase slurry polymerization, the concentration of the (i) solid complex titanium catalyst of the present invention on the polymerization reaction system is about 0.001 to 5 mmol, preferably about 0.001 to 0.5 mmol, of titanium atoms of the catalyst per 1 liter of solvent. Solvents that can be used in the liquid slurry polymerization include alkanes or cycloalkanes such as pentane, hexane, heptane, n-octane, isooctane, cyclohexane, methylcyclohexane; Alkylaromatics such as toluene, xylene, ethylbenzene, isopropylbenzene, ethyltoluene, n-propylbenzene, diethylbenzene; Halogenated aromatics such as chlorobenzene, chloronaphthalene and ortho-dichlorobenzene; And mixtures thereof.

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 20-200 degreeC is suitable, Preferably 20-95 degreeC is good. 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 by the polymerization method of the present invention is a solid ultra high molecular weight polyethylene, which may be an ethylene homopolymer or a copolymer of ethylene and an α-olefin, has an intrinsic viscosity of 3 to 50 dl / g, and an average particle size of 80 to 140 It is micrometer, and the yield of a polymer is also high enough, and the removal of a catalyst residue is not necessary and it has the outstanding apparent density and fluidity.

Through the catalyst preparation method of the present invention, it is possible to prepare a catalyst having excellent catalyst activity and controllable form of catalyst particles, high apparent density of the prepared polymerized polymer, and narrow particle size distribution of the polymer. It is possible to obtain new ultra high molecular weight polyethylene with few particles or fine particles.

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

Example  One

[Preparation of solid catalyst for the production of ultra high molecular weight polyethylene]

The catalyst was prepared through the following three steps.

(Iii) Step: Preparation of Magnesium Compound Solution

11.5 g of MgCl ₂ and 400 ml of decane were added to a 10 L reactor equipped with a mechanical stirrer replaced with a nitrogen atmosphere, and stirred at 300 rpm. 80 ml of 2-ethylhexanol was added thereto, and the temperature was raised to 120 ° C. and reacted for 3 hours. The homogeneous solution obtained after the reaction was cooled to room temperature (25 ° C).

(Ii) step: magnesium compound solution Diester  Contact reaction of compounds

3.3 ml of diethylphthalate was added to the magnesium compound solution obtained in step (i) and reacted for 1 hour.

(Iii) step: addition of titanium compound

The reaction solution of the magnesium compound solution and diester compound obtained in step (ii) was cooled to room temperature (25 ° C.), and a solution of 60 ml of titanium tetrachloride diluted with 50 ml of decane was added dropwise for 1 hour. When the dropping was completed, the temperature of the reactor was raised to 80 ° C. over 1 hour and maintained for 1 hour. After the stirring was stopped, the solution of the upper layer was separated, and then 300 ml of decane and 100 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. Thereafter, the reactor was cooled to room temperature and 400 ml of hexane was washed until unreacted free titanium tetrachloride was removed.

The titanium content of the solid catalyst thus prepared was 3.2% by weight.

[polymerization]

After the high-pressure reactor with a capacity of 2 liters was dried in an oven and assembled in a hot state, nitrogen and vacuum were alternately operated three times to make the inside of the reactor into a nitrogen atmosphere. After 1000 ml of n-hexane was injected into the reactor, 1 mmol of triisobutylaluminum and the solid catalyst prepared above were injected at 0.005 mmol based on the titanium atom. The polymerization was carried out for two hours while raising the temperature of the reactor to 70 ° C. while stirring at 700 rpm and adjusting the ethylene pressure to 200 psi. After the polymerization was completed, 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 powder of polyethylene.

Polymerization activity (kg polyethylene / g catalyst) was calculated as the weight (g) ratio of the resulting polymer per gram of catalyst used.

The particle size distribution of the polymer was measured using a laser particle analyzer (Mastersizer X, Malvern Instruments), and the distribution of the polymer was calculated as (d ₉₀ -d _{10 )} ) / d ₅₀ . Where d ₁₀ , d ₅₀ and d ₉₀ refer to particle sizes indicated by 10%, 50% and 90% of the sample, respectively, and d ₅₀ represents the average particle size. The polymerization results are shown in Table 1 together with the apparent density (g / ml) of the polymer.

The intrinsic viscosity of the polymer can be calculated by dissolving the polymer using a decahydronaphthalene solvent according to ISO 1628 Part 3 to measure the relative viscosity, and then extrapolating the relative viscosity value to a value of zero concentration. From this, the average molecular weight (Mv) was calculated using the Margolies's formula (Mv = 5.34 × 10 ⁴ × [η] ^1.49 , Mv = viscosity average molecular weight, η = intrinsic viscosity) which is well known in the art.

Example  2

In the step (ii) of the preparation of the catalyst of Example 1, the catalyst was prepared under the same conditions as in Example 1, except that diethylphthalate was adjusted to 1.7 mL, and the catalyst was obtained in the same manner as in Example 1. It superposed | polymerized easily. The results are summarized in Table 1.

Example  3

In the step (ii) of the preparation of the catalyst of Example 1, except that the diethyl phthalate was adjusted to 0.9 mL, the catalyst was prepared under the same conditions as in Example 1, and the catalyst was obtained in the same manner as in Example 1 It superposed | polymerized easily. The results are summarized in Table 1.

Example  4

In the step (ii) of preparing the catalyst of Example 1, except that 3.4 mL of diisobutyl phthalate was used instead of diethyl phthalate, a catalyst was prepared under the same conditions as in Example 1, and the reaction was performed using the obtained catalyst. The polymerization was carried out in the same manner as in Example 1. The results are summarized in Table 1.

Example  5

In the step (ii) of preparing the catalyst of Example 1, a catalyst was prepared under the same conditions as in Example 1, except that 3.4 ml of di-n-butylphthalate was used instead of diethyl phthalate, and the obtained catalyst was used. The polymerization was carried out in the same manner as in Example 1. The results are summarized in Table 1.

Comparative example  One

In step (ii) of the catalyst preparation process of Example 1, a catalyst was prepared under the same conditions as in Example 1, except that diethylphthalate was not used. The titanium content of the prepared catalyst was 4.8 wt%. The polymerization was carried out in the same manner as in Example 1 using the catalyst thus prepared. The results are shown in Table 1.

activation
(kg PE / g catalyst) Apparent density
(g / ml) Intrinsic viscosity
(Intrinsic Viscosity) (dl / g) Average molecular weight, Mv
(g / mol) Average particle
Size (μm) Particle size distribution Example 1 27.9 0.37 31.1 8.95 109.3 1.01 Example 2 29.8 0.38 29.8 8.40 124.9 0.99 Example 3 30.7 0.37 27.9 7.61 129.1 0.92 Example 4 28.4 0.38 33.3 9.91 122.4 0.96 Example 5 31.5 0.37 34.4 10.40 125.9 0.95 Comparative Example 1 24.8 0.21 19.4 4.43 98.3 5.6

Claims (7)

Solid complex titanium catalyst for preparing ultra high molecular weight polyethylene prepared according to a method comprising the following steps:
(Iii) contacting the magnesium halide compound with an alcohol to prepare a magnesium compound solution;
(Ii) reacting the magnesium compound solution with a diester compound; And
(Iii) preparing a catalyst by adding a titanium compound to the reactant of the magnesium compound solution and the diester compound.
The solid catalyst titanium catalyst for preparing ultra high molecular weight polyethylene according to claim 1, wherein the diester compound of step (ii) is a compound represented by the following general formula:
C ₆ H ₄ -1- [CO ₂ -R] -a- [CO ₂ -R '] ₂
(Wherein R and R ′ are hydrocarbons having 1 to 20 carbon atoms, which may be the same or different, and a is a natural number of 2, 3, or 4).
The method of claim 1, wherein the titanium compound of step (iii) is a general formula Ti (OR) _a X _4-a (R is a hydrocarbon group having 1 to 20 carbon atoms, X is a halogen atom, and a is 0≤a≤4 Solid complex titanium catalyst for ultra-high molecular weight polyethylene production, characterized in that the compound).
The method of claim 1, wherein the titanium compound of step (iii) is TiCl ₄ , TiBr ₄ , TiI ₄ , Ti (OCH ₃ ) Cl ₃ , Ti (OC ₂ H ₅ ) Cl ₃ , Ti (OC ₂ H ₅ ) Br ₃ , Ti (O (iC ₄ H ₉ )) Br ₃ , Ti (OCH ₃ ) ₂ Cl ₂ , Ti (OC ₂ H ₅ ) ₂ Cl ₂ , Ti (O (iC ₄ H ₉ )) ₂ Cl ₂ , Ti (OC ₂ H ₅ ) ₂ Br ₂ , Ti (OCH ₃ ) ₄ , Ti (OC ₂ H ₅ ) ₄ , Ti (OC ₄ H ₉ ) _{4 It} is characterized in that the solid complex titanium catalyst for producing ultra high molecular weight polyethylene.
The solid complex titanium catalyst for preparing ultra high molecular weight polyethylene according to claim 1, further comprising further reacting the catalyst prepared in step (iii) with an additional titanium compound.
A process for producing ultra high molecular weight polyethylene comprising polymerizing or copolymerizing ethylene in the presence of a solid complex titanium catalyst according to any one of claims 1 to 5 and an organometallic compound.
The method of claim 6, wherein the organometallic compound is an organoaluminum compound.