Title of Invention	“METHOD FOR PREPARING A CATALYST COMPONENT FOR ETHYLENE POLYMERIZATION AND COPOLYMERIZATION”
Abstract	The present invention discloses a method for preparing a catalyst component for polymerization and copolymerization of ethylene. The method comprises a step of reacting a magnesium solution with a liquid titanium compound having at least one alkoxy group to form a slurry product. The method further comprises contacting the slurry product with a liquid titanium halide compound to produce a contact product, elevating temperature of the contact product to a temperature between and including 110°C and 130°C, and maintaining the contact product at this temperature until a solid catalyst component is formed. During elevation of the temperature of the contact product, an organosilicon compound having no active hydrogen is added to the contact product. The solid catalyst component is washed with a halogenated hydrocarbon solution.

Title of Invention

“METHOD FOR PREPARING A CATALYST COMPONENT FOR ETHYLENE POLYMERIZATION AND COPOLYMERIZATION”

Abstract

The present invention discloses a method for preparing a catalyst component for polymerization and copolymerization of ethylene. The method comprises a step of reacting a magnesium solution with a liquid titanium compound having at least one alkoxy group to form a slurry product. The method further comprises contacting the slurry product with a liquid titanium halide compound to produce a contact product, elevating temperature of the contact product to a temperature between and including 110°C and 130°C, and maintaining the contact product at this temperature until a solid catalyst component is formed. During elevation of the temperature of the contact product, an organosilicon compound having no active hydrogen is added to the contact product. The solid catalyst component is washed with a halogenated hydrocarbon solution.

Full Text	TECHNICAL FIELD The present invention relates generally to a method for preparing a catalyst component for ethylene polymerization and copolymerization. The present invention also relates generally to a catalyst or catalytic system comprising catalyst components prepared by the method of the present invention and an organometallic compound. BACKGROUND OF THE INVENTION In recent years, many research projects have been conducted in the field to develop various methods and catalysts for improving the physical properties of polyolefin polymers. In particular, researchers are interested in finding techniques for reducing the amount of fine particles of polyolefin polymer. Reduction of the amount of fine particles is desirable for a number of reasons. Exemplary reasons include inhibiting the formation of deposits during the polymerization and preventing scattering of fine particles of polymer outside of the system. Furthermore, separation and filtration of the polymer slurry is easier due to a narrower particle size distribution. In addition, the drying efficiency is enhanced due to the improvement in polymer fluidity. Japanese application 59-118120 discloses the production of polymer having a low amount of fine particles by utilizing a catalyst system that includes a mixture of an ingredient obtained from the reaction of magnesium, titanium, organoaluminum, silicon and halogenated aluminum compounds in sequence and a catalyst ingredient which is an organometallic compound. WO92/07008 discloses a method of manufacturing a polyolefin using a catalyst system of an ingredient (A) and an ingredient (B) wherein the ingredient (A) is prepared from a metallic magnesium or an oxygen-containing organic compound of magnesium, a mixture of a monohydroxylated organic compound and a polyhydroxylated organic compound, oxygen-containing organic compounds of titanium, halogenated aluminum compound, silicon compound and ingredient B is an organometallic compound of metals from Group Ia, IIa, IIIa or IVa of the Periodic Table. Although the method disclosed by the above-mentioned patent applications may produce polymer with small amount of fine particles, these methods are complicated. Therefore, there is a demand for catalyst for polymerization and copolymerization of ethylene which can be prepared by a simple process, with high polymerization activity and an ability to facilitate production of polymers with narrow particle size distribution and small amount of fine particles. SUMMARY OF THE INVENTION The present invention is a method for preparing a catalyst component for at least one of polymerization and copolymerization of ethylene comprising the following steps of (i) reacting a magnesium solution with a liquid titanium compound having at least one alkoxy group to form a slurry product, (ii) contacting the slurry product with a liquid titanium halide compound to produce a contact product, (iii) elevating the temperature of the contact product to a temperature of 110°C to 130° C, (iv) maintaining the contact product at this temperature until a solid catalyst component is formed, and (v) washing the solid catalyst component with a halogenated hydrocarbon solution, wherein the solid catalyst component comprises at least one of titanium, magnesium and silicon. DETAILED DESCRIPTION The present invention provides a method for preparing a catalyst component for ethylene polymerization and copolymerization. The catalyst component of the present invention has a higher catalytic activity than previously disclosed or existing catalysts and also results in a decreased formation of fine particles or low polymers. Furthermore, polymers produced by the method of the present invention have a narrow particle size distribution, which results in improvement of polymer flowability during the polymerization process. The meaning and scope of the term “polymerization” used herein is not limited to “homopolymerization”, but also includes “copolymerization” or “heteropolymerization”. Likewise, the meaning or scope of the term “polymer” used herein is not only limited to “homopolymer”, but also includes “copolymer” or “heteropolymer”. Each ingredient, element or compound used for preparing a catalyst component provided by the invention is described below. (a) Magnesium compound In the preparation of the catalyst or catalyst component provided by the present invention, a magnesium compound is used. Preferably, the magnesium compound is used in a liquid state (and can be referred to as a magnesium solution). This is preferably achieved by dissolving a solid magnesium compound with an electron donor compound such as alcohols. Preferably, the magnesium compound is a halogenated magnesium compound. Preferably, the halogenated magnesium compound is dissolved in an alcohol. More preferably, the halogenated magnesium compound is a dihalogen magnesium compound dissolved in an aliphatic alcohol. Halogenated magnesium compounds used in this invention include, but are not limited to, the following; dihalogenated magnesium compound such as magnesium chloride, magnesium iodide, magnesium fluoride and magnesium bromide; alkyl magnesium halide compound such as methylmagnesium halide, ethylmagnesium halide, propylmagnesium halide, butylmagnesium halide, and amylmagnesium halide; alkoxymagnesium halide compound such as methoxymagnesium halide, ethoxymagnesium halide, isopropoxymagnesium halide and butoxymagnesium halide. These halogenated magnesium compounds can be used singularly or in combination (as a mixture of two or more halogenated magnesium compounds). Moreover, the above halogenated magnesium compounds can be effectively used in the form of a complex compound comprising other metals such as aluminum zinc, boron, sodium and potassium. Alternatively, the halogenated magnesium compound may be mixed with one or more of the above-listed metals. The magnesium compounds or halogenated magnesium compounds used for preparing the catalyst component of the present invention also comprise alternative compounds that cannot be represented by a chemical formula. This may occur depending on production methods of such magnesium compounds. Alternative compounds may generally be referred to as mixtures of magnesium compounds. For example,the alternative compound or mixture of magnesium compounds may be obtained by reacting the magnesium compound with siloxane compounds or with silane compounds comprising a halogen, an ester or an alcohol. The alternative compound or mixture of magnesium compounds may also be obtained by reacting magnesium metal with an alcohol, a phenol or an ether in the presence of a halosilane, phosphorus pentachloride, or thionylchloride. The magnesium compound provided by this invention may generally be represented by the following formula: XnMgR2-n Wherein n is a number of 0 = n (b) Liquid titanium compound having at least one alkoxy group A titanium compound that has at least one alkoxy group can be represented by the following formula: Ti(OR)nX4-n wherein n is a number between and including 1 and 4; R is a hydrocarbon group comprising between and including 1 and 20 carbon atoms; and X is a halogen atom. For example, R in the above formula can be alkyl group such as methyl, ethyl, propyl, isopropyl, butyl, isobutyl, tert-butyl, amyl, isoamyl; aryl groups such as phenyl, cresyl, xylyl and naphtyl groups; allyl groups such as propenyl group; and aralkyl groups such as benzyl group. Among them, alkyl groups comprising 2 to 10 carbon atoms or aryl groups having 6 to 10 carbon atoms are preferable, and straight chain alkyl groups comprising 2 to 10 carbon atoms are particularly preferable. The titanium compound represented by the above formula may have two or more different -OR groups. The halogen atom or “X” in the formula at (b) (or for the liquid titanium compound) as shown above is for example, a chlorine atom, a bromide atom or an iodine atom. Of these examples of halogen atoms, the chlorine atom is particularly preferred. Preferably “n” in the formula at (b) (or for the titanium compound) as shown above is a number between and including 2 and 4, and 4 is particularly preferred. Exemplary titanium compounds having at least one alkoxy group, and that are represented by the above formula include but are not limited to: hydrocarbyloxytitanium trihalides such as methoxyltitanium trichloride, ethoxytitanium trichloride and butoxytitanium trichloride; dihydrocarbyloxytitanium dihalides such as dimethoxytitanium dichloride, diethoxytitanium dichloride and dibutoxytitanium dichloride; trihydrocarbyloxytitanium monohalides such as trimethoxytitanium chloride, triethoxytitanium chloride, and tribuyoxytitanium chloride; and tetrahydrocarbyloxytitanium compounds such as tetramethoxytitanium, tetraethoxytitanium, and tetrabutoxytitanium. Particularly preferred titanium compounds are tetrahydrocarbyloxytitanium compounds, and more preferably tetrabutoxytitanium. Preferably 0.05 to 0.40 mole of the liquid titanium compound is used with or for one mole of the magnesium compound. More preferably, 0.10 to 0.30 mole of the liquid titanium compound is used with or for one mole of the magnesium compound. (c) Liquid titanium halide compound The liquid titanium halide compound provided by the present invention is preferably a tetrahalogenated titanium compound. The tetrahalogenated titanium is for example titanium tetrachloride, titanium tetra bromide and titanium tetra iodide. A mixture of the above examples of tetrahalogenated titanium compounds may also be used. In this invention, the liquid titanium halide compound may be a singular or a combination of the above-listed exemplary tetrahalogenated titanium compounds. Preferably, the liquid titanium halide compound is titanium tetrachloride. Preferably 0.1 to 100 mole of the liquid titanium halide is used with or for one mole of the magnesium compound. More preferably, 3 to 40 mole of the liquid titanium halide is used with or for one mole of the magnesium compound. (d) Organosilicon compound comprising no active hydrogen An organosilicon compound comprising no active hydrogen according to this invention can be represented by the general formula of R1aR2bR3cR4dSi (OR5) e wherein each R1, R2, R3, R4, and R5 is a hydrocarbon comprising 1 to 12 carbon atoms. Each of R1, R2, R3, R4, and R5 may be the same or different from each other, and a, b, c, d, e are integers between and including 0 and 4, and satisfy the formula a+b+c+d+e=4. The organosilicon compound is for example: dimethyldimethoxysilane, dimethyldiethoxysilane, diphenyldimethoxysilane, methylphenyldimethoxy silane, diphenyldiethoxysilane, methyltrimethoxysilane, ethyltriethoxysilane, vinyltrimethoxysilane, phenyltrimethoxysilane, methyltriethoxysilane, ethyltriethoxysilane, vinyltriethoxysilane, butyltriethoxysilane, phenyltriethylethoxysilane, ethyltripropoxysilane, phenyltriethoxysilane, ethylsilicate, butylsilicate, tetramethoxysilane, tetraethoxysilane, or tetrabutoxysilane. Preferably 0.1 to 3 mole of the organosilicon compound is used with or for one mole of the magnesium compound. More preferably, 0.2 to 1.5 mole of the organosilicon compound is used with or for one mole of the magnesium compound. (e) Other ingredients/elements used for preparing the catalyst component As previously described, the magnesium compound is preferably in the liquid state, and can be referred to as a magnesium solution. Preparation of a solution of the magnesium compound, comprises dissolving the magnesium compound by using the alcohol as a solvent, either in the presence or in the absence of a hydrocarbon solvent. The hydrocarbon solvent is preferably a halogenated hydrocarbon solvent. The presence of the halogenated hydrocarbon solvent for dissolving the magnesium compound is preferred. Type of alcohol used include, but is not limited to, alcohols comprising between and including 1 and 20 carbon atoms, such as methanol, ethanol, propanol, butanol, pentanol, hexanol, octanol, decanol, dodecanol, bezylalcohol, phenylethyl alcohol, isopropyl benzyl alcohol and cyclohexanol. Alcohols comprising not more than 12 carbon atoms are more preferred. As described above, other ingredients used for preparing the catalyst component provided by the present invention comprise hydrocarbon compounds and halogenated hydrocarbon compounds. The hydrocarbon compound is preferably used as a solvent medium. The hydrocarbon compound preferably comprises 1 to 20 carbon atoms. The hydrocarbon compound is for example, or may comprise one or more of, pentane, hexane, heptane, decane, isoparafin, dodecane, benzene toluene or xylene. Halogenated hydrocarbons are also preferably used for preparing the magnesium solution as a solvent medium. The halogenated hydrocarbons comprises between and including 1 and 20 carbon atoms and at least one halogen atom ligand. The halogenated hydrocarbon may comprise one or more of, monochloromethane, dichloromethane, trichloromethane, tetrachloromethane, monochloroethane, 1,2-dichloroethane, monochloropropane, monochlorobutane, monobromopropane, monodiodomethane, or monoiodomethane. Preferably, the halogenated hydrocarbon comprises at least one chloride atom. Preparation of catalyst component The catalyst component for ethylene polymerization and copolymerization as provided by the present invention can be prepared by a method comprising the following steps: (i) Reacting the magnesium solution with the liquid titanium compound, the liquid titanium compound comprising at least one alkoxy group, to form a slurry product; (ii) Contacting the slurry product formed in step (i) and the liquid titanium halide to produce a contact product; (iii) Elevating the temperature of the contact product produced in step (ii) to a temperature between and including 110°C to 130°C. The contact product is then maintained at this temperature until a solid particle of the catalyst component is formed. During the elevation of the temperature of the contact product, an organosilicon compound having no active hydrogen is added to the contact product; and (iv) Washing the solid particle of catalyst component with a halogenated hydrocarbon solution. In the step (i), the reaction between the magnesium solution and the liquid titanium compound comprising at least one alkoxy group is carried out at a controlled temperature in order to control shape and particle size distribution of the slurry product formed. The temperature is also controlled for forming a good shape of the slurry product as required. Preferably the reaction is carried out at a temperature between and including 0°C and 70°C. More preferably, the reaction is carried out at a temperature between 20°C and 50°C. The reaction between the magnesium solution with the liquid titanium compound occurs over a duration of approximately 0.5 hours to 3 hours to complete the reaction and form the slurry product. The slurry product preferably has an average particle size of smaller than 1 micron. The slurry product obtained from this step is further reacted with the liquid titanium halide compound in the step (ii) to form the contact product at a predetermined temperature of between and including -50°C to 50°C, or more preferably between -20°C to 20°C. In order to complete the reaction between the slurry product and the liquid titanium halide compound of step (ii), and to result a good shape and particle size distribution of the contact product, step (ii) preferably occurs over a duration of about 0.5 hours to 3 hours. In order to increase quality of the formed catalyst component in term of morphology, particle size distribution and catalytic activity, the contact product is preferably further reacted with the organosilicon compound, which comprises no active hydrogen, at a temperature between and including 20°C and 80°C to form the solid particle of catalyst component. More preferably, the contact product is further reacted with the organosilicon compound at a temperature between and including 40°C and 60°C to form the solid particle of catalyst component. The organosilicon compound comprising no active hydrogen used in this reaction may be one of the exemplary organosilicon compounds described above, or a combination of two or more different exemplary organosilicon compounds. After the addition of the organosilicon compound comprising no active hydrogen, the temperature is raised up to between and including 110°C to 130°C, over a duration of about 0.5 hours to 3 hours, in order to completely form the solid catalyst component. The formed solid catalyst component is then further washed with the halogenated hydrocarbon solution. Alternatively, the formed solid catalyst component may further react with the liquid titanium halide compound before being washed with the halogenated hydrocarbon solution in the step (iv). The liquid titanium halide compound may be used in isolation. Alternatively, the liquid titanium halide may be used in combination with one or more of the exemplary halogenated hydrocarbons as listed above. Preferably, the liquid titanium halide compound used in the step (ii) is titanium tetrachloride. The solid catalyst component obtained by the above-described method preferably comprises magnesium, titanium, halogen and silicon. Ethylene Polymerization The solid catalyst component (also known as the catalyst component) produced by the above method can be used for polymerization of ethylene. Preferably, the catalyst component can be used for homopolymerization of ethylene. Further preferably, the catalyst component can also be used for copolymerization of ethylene and alpha-olefins, which have three or more carbon atoms, such as propylene, 1-butene, 1-pentene or 1-hexene. The polymerization reaction using the catalyst component prepared by the method provided by the present invention may be carried out by using a catalyst system. The catalyst system comprises the catalyst component prepared as described above. The catalyst component preferably comprises at least one of magnesium, titanium, halogen, and silicon. The catalyst system preferably further comprises organometallic compounds that comprise at least one metal selected from Group II or Group III of the Periodic Table. The organometallic compound may be represented by a formula of MRn wherein “M” is a metal selected from Group II or Group III of the Periodic Table, such as magnesium, calcium, zinc, boron, aluminum, or gallium, “R” is an alkyl group comprising 1 to 10 carbon atoms, such as a methyl, ethyl, butyl, hexyl, or octyl, and “n” is the atomic valence of the selected metal. Preferably, the organometallic compound is trialkylaluminum, which comprises an alkyl group of 1 to 8 carbon atoms, such as triethylaluminum, triisobutylaluminum, and trioctylaluminum. Alternatively, the organometallic compound comprises a mixture of trialkylaluminums. Further alternatively, the organometallic compound is an organoaluminum comprising one or more halogens or hydride groups. Examples of organoaluminums include, but are not limited to, ethylaluminum dichloride, diethylaluminum chloride, ethylaluminum sesquichloride and diisobutylaluminum hydride. Pre-polymerization Reaction/Process The catalyst component obtained from the above preparation may be pre-polymerized with ethylene or alpha-olefin before their use in the polymerization reaction. The pre-polymerization of the catalyst component with ethylene or alpha-olefin may be carried out in the presence of a hydrocarbon solvent, for example hexane or pentane, at predetermined temperature. In addition, the pre-polymerization of the catalyst component with ethylene or alpha-olefin is preferably performed under a predetermined pressure, and in the presence of the organoaluminum compound, for example triethylaluminum. In order to acquire a required shape and an enhanced mechanical strength of the catalyst component for thereby forming the ethylene or alpha-olefin polymer over the catalyst component, a weight of alpha-olefin to that of the catalyst component after the pre-polymerization is preferably approximately 0.1 to 20. The polymerization reaction as provided by the present invention, which utilizes the catalyst component, is preferably performed at a predetermined polymerization temperature of between and including 20°C and 300°C. More preferably, the polymerization reaction is performed at a polymerization temperature of between and including 50°C to 150°C. In addition, the polymerization reaction is preferably performed at an operating pressure of not more than 100 bar, and more preferably at between and including 2 and 50 bar. When hydrogen is used in the polymerization reaction, average molecular weight and molecular weight distribution of polymer produced by the polymerization reaction (i.e. product of the polymerization reaction) may be changed. The polymerization reaction may be performed by gas phase polymerization or bulk phase polymerization in the absence of an organic solvent. Alternatively, the polymerization reaction may be performed by liquid slurry polymerization in the presence of an organic solvent. These polymerization reactions are preferably performed in the absence of oxygen, water, and other catalytic poison compounds. The polymer produced by the polymerization reaction that uses the catalyst component provided by the present invention preferably has an enhanced shape. Moreover the polymer produced by the polymerization reaction that uses the catalyst component provided by the present invention preferably are not adversely affected, and also do not melt on reactor walls. This is preferably because of reduced quantity of fine particles or low polymers, and an enhanced flowability of the produced polymer particles. For liquid slurry polymerization, the catalyst component used for the polymerization reaction preferably comprises approximately 0.0001 mmol to 5 mmol of titanium atom per one liter of solvent used. In addition, preferably approximately 1 to 2,000 mole of organometallic material is used per one mole of titanium atom of the catalyst component used for the polymerization reaction. As described above, a hydrocarbon solvent comprising one or more hydrocarbon compounds as listed above, for example pentane, hexane, heptane, octane, isoparafin, toluene, benzene, xylene, cyclohexane is preferably used for the polymerization reaction. Polyethylene produced by the polymerization reaction using the solid catalyst component provided by the present invention preferably has a bulk density between and including 0.20 g/cm3 and 0.60 g/cm3, and more preferably between 0.25 g/cm3 and 0.60 g/cm3, as well as a melt flow index (ASTM D1238E) between and including 0.01 g/10min and 5000 g/10min. Furthermore, additives including, but not limited to, heat stabilizers, weathering stabilizers, antistatic agents, antiblocking agents, lubricants, nucleating agents, pigments, dyes and inorganic and organic fillers may be further added as according to commercial requirements. The characteristics of the produced polymer by the polymerization process provided by the present invention, for example melt flow rate, particle size distribution, and the bulk density, are investigated by methods or techniques known in the art as described below. For example: a) Melt Flow Rate (MFR) of polymer particles is determined by using the method according to ASTM-1238. b) Polymer particle size distribution is analyzed by utilizing RETSCH AS-200 device. c) Bulk density of polymer is determined by using the method according to ASTM-D1859-89. EXAMPLE The following examples are included to illustrate exemplary embodiments of the present invention. The following examples do not define or limit the scope of the present invention. It should be appreciated by those of skill in the art that the techniques disclosed in the following examples represent exemplary embodiments of techniques and processes provided by the present invention. It will however be appreciated by those of skill in the art, in light of the present disclosure, that changes can be made to the exemplary embodiments and still obtain a like or similar result without departing from the spirit and scope of the present invention. Example 1 Preparation of a solid particle catalyst (1) Preparation of a magnesium solution /homogenous solution Reactants, namely 10 g (0.105 mol) of MgCl2, 100 ml of decane, 12 ml of 1,2-dichloroethane, and 51 ml (0.325 mol) of 2-ethylhexyl alcohol were introduced into a volumetric flask of 1 Liter. The volumetric flask comprised a magnetic stirrer therewithin and was blanked with a nitrogen atmosphere. The reactants were mixed by the magnetic stirrer at a stirring speed of 300 rpm, and heated to 130°C, for 3 hours to produce a homogeneous solution or a magnesium solution. The homogenous solution was then cooled to a temperature of 50°C. After the homogenous solution was cooled to 50°C, 12.5 ml (0.037mol) of titanium butoxide was added into the homogenous solution. Mixture of the homogenous solution and titanium butoxide was then stirred at 50°C for 2 hours to produce or obtain a slurry product. (2) 51 ml (0.47mol) of TiCl4 was dripped into the above slurry product, which was cooled down to 0°C over a time period of 1 hour with stirring. After the addition of TiCl4 into the slurry product was completed, the temperature was maintained at 0°C for a further 1 hour to form a solid product. The solid product is also known as the catalytic component. (3) The temperature of the above reactants in (1) and (2) was then elevated from 0°C to 50°C over a period of 1 hour. 3 ml (0.27 mol) of tetraethylorthosilicate was added to the above reactants to form a mixture. The temperature of the mixture was then raised to 110°C over a period of 1 hour. The temperature of the mixture was then maintained at 110°C for 2 hours with stirring. (4) After completion of the steps (1) to (3), the solid product was separated by hot decanter. The solid product is then treated with 200 ml of 1,2-dichloroethane. The decanted solid product was also sufficiently washed with hexane and decane at 100°C until no trace of titanium component in the supernatant was found. The atomic molar-ratio of titanium to magnesium in the obtained catalyst component was 0.21. Ethylene Polymerization A 2 liter stainless steel reactor equipped with a mechanical stirrer and an advanced temperature controller system was purged with nitrogen atmosphere. 500 ml of hexane was introduced into the reactor. 3 atm of hydrogen was then added after an introduction of 1 mmol of triethylaluminum and the solid catalyst component comprising 0.003 mol of titanium atom. The temperature of the reactor was increased to 80°C. Stirring speed of the mechanical stirrer was set at 500 rpm. Ethylene was added into the reactor and the pressure of ethylene within the reactor was set at 8 atm. The polymerization of ethylene (i.e. polymerization reaction) was performed for 2 hours. After the polymerization reaction, the temperature of the reactor was reduced to room temperature, and the pressure within the reactor was released. A predetermined amount of ethanol was introduced into the reactor to stop the polymerization reaction. Produced ethylene polymer was collected, and dried in a vacuum oven at 50°C for at least 3 hours to obtain a free-flow polyethylene powder. The polyethylene powder was obtained in a yield of 369 g (or 61.57 kgPE/mmolTi), has a MFR (i.e. melt flow rate) of 0.55 g/10min, and has an apparent bulk specific gravity of 0.31 g/cc. Particle size distribution of the polyethylene powder is shown in Table 2. Example 2 A catalyst component was prepared in the same procedures as in Example 1, except that 12.5 ml of titanium butoxide was not introduced into the magnesium solution in step (1). The atomic molar-ratio of titanium to magnesium in the obtained catalyst was 0.15. Ethylene polymerization (i.e. polymerization reaction) was carried out as according to the steps described in Example 1. Polymer of Example 2 was obtained in a yield of 355 g (or 59.24 kgPE/mmolTi), has a MFR (i.e. melt flow rate) of 0.30 g/10min, and has an apparent bulk specific gravity of 0.31 g/cc. Particle size distribution of the resulting Polyethylene powder of Example 2 is shown in Table 2. Example 3 A catalyst component was prepared in the same procedures as in Example 1, except that 3 ml of tetraethylorthosilicate was not introduced to the contact product in step (3). The atomic molar-ratio of titanium to magnesium in the obtained catalyst component was 0.18. Polymerization of ethylene (i.e. polymerization reaction) was carried out according to the steps described in Example 1. The polymer was obtained in a yield of 220 g (or 36.74 kgPE/mmolTi), has a MFR (i.e. melt flow rate) of 0.28 g/10min, and an apparent bulk specific gravity of 0.30 g/cc. Particle size distribution of the resulting polyethylene powder is shown in Table 2. Example 4 A catalyst component was prepared in the same procedures as in Example 1, except that 200 ml of 1,2-dichloroethane was not introduced to treat the solid product produced in step (4). The atomic molar-ratio of titanium to magnesium in the obtained catalyst was 0.20. Polymerization of ethylene (i.e. polymerization reaction) was carried out according to the steps described in Example 1. The polyethylene powder was obtained in a yield of 344 g (or 57.32 kgPE/mmolTi), has a MFR (i.e. melt flow rate) of 0.26 g/10min and an apparent bulk specific gravity of 0.21 g/cc. Particle size distribution of the resulting polyethylene powder is shown in Table 2. Example 5 A catalyst component was prepared in the same procedures as in Example 1, except that the 3 ml of tetraethylorthosilicate introduced to the contact product in step (3) was replaced by 2.5 ml of tributylphosphate. The atomic molar-ratio of titanium to magnesium in the obtained catalyst was 0.23. Polymerization of ethylene (i.e. polymerization reaction) was carried out according to the steps described in Example 1. The polyethylene powder or polymer was obtained in a yield of 204 g (or 34.13 kgPE/mmolTi), has a MFR (i.e. melt flow rate) of 0.77 g/10min and an apparent bulk specific gravity of 0.30 g/cc. Particle size distribution of the resulting polyethylene powder is shown in Table 2. Example 6 A catalyst component was prepared in the same procedures as in Example 1, except that 200 ml of TiCl4 was introduced to the solid product before treating the solid product with 1,2-dichloroethane upon completion of the step (3). The atomic molar-ratio of titanium to magnesium in the obtained catalyst was 0.20. Polymerization of ethylene (i.e. polymerization reaction) was carried out according to the steps described in Example 1. The polyethylene powder or polymer was obtained in a yield of 343 g (or 57.32 kgPE/mmolTi), has a MFR (i.e. melt flow rate) of 0.51 g/10min, and an apparent bulk specific gravity of 0.28 g/cc. Particle size distribution of the resulting polyethylene powder is shown in Table 2. Example 7 A catalyst component was prepared in the same procedures as in Example 1, except that 5 ml (0.45mol) of tetraethylorthosilicate was introduced to the contact product in step (3). The atomic molar-ratio of titanium to magnesium in the obtained catalyst was 0.19. Polymerization of ethylene (i.e. polymerization reaction) was carried out according to the steps described in Example 1. The polymer was obtained in a yield of 357 g (or 59.61 kgPE/mmolTi), has a MFR (i.e. melt flow rate) of 0.25 g/10min, and an apparent bulk specific gravity of 0.30 g/cc. Particle size distribution of the resulting polyethylene powder is shown in Table 2. Example 8 A catalyst component was prepared in the same procedures as in Example 1, except that 25 ml (0.074mol) of titanium butoxide was introduced into magnesium solution in step (1). The atomic molar-ratio of titanium to magnesium in the obtained catalyst was 0.23. Polymerization of ethylene (i.e. polymerization reaction) was carried out according to the steps described in Example 1. The polymer was obtained in a yield of 245 g (or 40.88 kgPE/mmolTi), has a MFR (i.e. melt flow rate) of 0.28 g/10min, and an apparent bulk specific gravity of 0.28 g/cc. Particle size distribution of the resulting polyethylene powder is shown in Table 2. Existing Method Preparation of a solid particle catalyst In a 1 liter glass reactor, 10 g (0.105 mol) of MgCl2 was suspended in 300 ml of hexane. To the suspension of MgCl2 and hexane, 42 ml (0.714 mol) of ethanol was introduced over a period of 1 hour. Temperature of the suspension of MgCl2 and hexane is controlled at 20°C with stirring. Reaction between the MgCl2 and hexane occurs during the stirring for another 1 hour at 20°C. 85 gram (0.315 mol) of diethylaluminum chloride was then dropped or introduced into the suspension of MgCl2 and hexane to form a mixture, which is maintained at a temperature of at 20°C for one more hour with stirring. Next, 40.3 ml (0.368) of TiCl4 was slowly added into the mixture at 30°C with stirring. The temperature was raised to 80°C over a period of 2 hours and a catalyst is produced. After the reaction was completed, a solid catalyst was separated from the mixture, which is at a liquid phase, at room temperature. The solid product was sufficiently washed with hexane until no titanium component in the supernatant was found. The final solid catalyst was obtained in the form of a suspended solid catalyst in a hexane solvent. The atomic molar-ratio of titanium to magnesium in the obtained catalyst was 0.13. Polymerization of ethylene (i.e. polymerization reaction) was carried out according to the steps described in Example 1. The polyethylene powder or polymer was obtained in a yield of 268 g (or 44.77 kgPE/mmolTi), has a MFR (i.e. melt flow rate) of 0.26 g/10min, and an apparent bulk specific gravity of 0.30 g/cc. Particle size distribution of the resulting polyethylene powder is shown in Table 2. Table 1 Example Catalytic activity (kgPE/mmolTi) Bulk specific gravity (g/cm3) MFR (g/10min) 1 61.57 0.31 0.55 2 59.23 0.31 0.30 3 36.74 0.30 0.28 4 57.32 0.21 0.26 5 34.13 0.30 0.77 6 57.32 0.28 0.51 7 59.61 0.30 0.25 8 40.88 0.28 0.28 Existing Method 44.77 0.30 0.26 Table 2 Example Particle size distribution >500µm >250µm >180µm >106µm >75µm >45µm 1 4.8 16.9 59.4 16.4 1.1 1.0 2 5.3 48.6 27.8 15.7 2.1 0.4 3 4.6 7.9 24.9 51.7 7.5 3.3 4 2.4 68.2 22.3 5.5 1.0 0.6 5 27.6 17.1 11.3 20.2 13.6 8.3 6 2.4 68.2 22.3 5.5 1.0 0.6 7 3.6 33.1 40.9 16.7 3.9 1.8 8 2.5 20.1 38.6 32.2 5.1 1.4 Existing Method 20.6 10.5 12.1 29.2 16.3 9.6 As shown in the above tables, the catalytic activity of the catalytic component provided by the present invention can have an enhanced catalytic activity (kgPE/mmolTi) as compared with the catalytic activity of the catalyst of the existing method. In addition, the MFR (g/10min) of the polymer produced by the polymerization reaction using the catalytic component provided by the present invention can be higher than that of the polymer of the existing method. Furthermore, particle size distribution of polymers produced by the polymerization reaction using the catalytic component provided by the present invention can be narrowed. We Claim: 1. A method of preparing a catalyst component for at least one of polymerization and copolymerization of ethylene comprising: (i) reacting a magnesium solution with a liquid titanium compound having at least one alkoxy group to form a slurry product, (ii) contacting the slurry product with a liquid titanium halide compound for producing a contact product; (iii) elevating temperature of the contact product to a temperature of between and including 110°C and 130°C; (iv) maintaining the contact product at the temperature for forming a solid catalyst component; and (v) washing the solid catalyst component with a halogenated hydrocarbon solution, wherein the solid catalyst component comprises at least one of titanium, magnesium and silicon. 2. The method as in claim 1, further comprising: adding an organosilicon compound having no active hydrogen to the contact product during elevating of the temperature in the step (iii). 3. The method of claim 1, further comprising: treating the solid catalyst component with an additional liquid titanium compound, wherein the treating of the solid catalyst component occurs before washing the solid catalyst component with the halogenated hydrocarbon solution in the step (v). 4. The method of claim 1, wherein the liquid titanium compound comprising at least one alkoxy group is represented by a formula of Ti(OR)nX4-n, and wherein n is a number between and including 1 and 4; R is a hydrocarbon group comprising between and including 1 and 20 carbon atoms; and X is a halogen atom. 5. The method of claim 1, wherein the liquid titanium halide compound is a tetrahalogenated titanium or a mixture of the tetrahalogenated titanium with a titanium compound comprising at least one alkoxy group. 6. The method of claim 1, wherein the organosilicon compound is a compound represented by a formula R1aR2bR3cR4dSi (OR5)e, and wherein each of R1, R2, R3, R4, and R5 is a hydrocarbon comprising between and including 1 and 12 carbon atoms, each of R1, R2, R3, R4 and R5 being one of the same and different from each other, and a, b, c, d, e are integers between 0 and 4. 7. The method of claim 1, wherein the molar ratio of the liquid titanium compound comprising at least one alkoxy group to the magnesium solution is approximately between and including 0.05 mole and 0.40 mole per one mole of the magnesium solution. 8. The method of claim 1, wherein the reaction between the magnesium solution and the liquid titanium compound having at least one alkoxy group is carried out at a temperature of between and including 0°C to 70°C. 9. The method of claim 1, wherein the amount of the liquid titanium halide compound is approximately between and including 0.1 mole and 100 mole per one mole of the magnesium solution. 10. The method of claim 1, wherein the contacting reaction between the slurry product and the liquid titanium halide compound is carried out at the temperature of between and including -50°C and 50°C. 11. The method of claim 2, wherein the amount of the organosilicon compound comprising no active hydrogen is approximately between and including 0.1 mole to 3 mole per one mole of the magnesium solution. 12. The method of claim 2, wherein the organosilicon compound comprising no active hydrogen is added to the contact product at a temperature of between and including 20°C and 80°C. 13. A catalyst system for at least one of polymerization and copolymerization of ethylene comprising: (a) the catalyst component as claimed in any one of claim 1 to 12; and (b) an organometallic compound comprising at least one metal selected from Group II and Group III of the Periodic Table. 14. An ethylene polymerization process comprising polymerizing ethylene in the presence of the catalyst system as claimed in claim 13. 15. An ethylene copolymerization process comprising copolymerizing ethylene and at least one of a comonomer and a polymer in the presence of the catalyst system as claimed in claim 13. Dated this 22nd day of December, 2008 [GOUTAM BHATTACHARYYA] OF K & S PARTNERS ATTORNEY FOR THE APPLICANT(S) ABSTRACT Method for Preparing a Catalyst Component for Ethylene Polymerization and Copolymerization The present invention discloses a method for preparing a catalyst component for polymerization and copolymerization of ethylene. The method comprises a step of reacting a magnesium solution with a liquid titanium compound having at least one alkoxy group to form a slurry product. The method further comprises contacting the slurry product with a liquid titanium halide compound to produce a contact product, elevating temperature of the contact product to a temperature between and including 110°C and 130°C, and maintaining the contact product at this temperature until a solid catalyst component is formed. During elevation of the temperature of the contact product, an organosilicon compound having no active hydrogen is added to the contact product. The solid catalyst component is washed with a halogenated hydrocarbon solution. Furthermore, the solid catalyst component can be treated at least once with an additional liquid titanium compound having at least one halogen ligand before washing with the halogenated hydrocarbon solution. The catalyst component prepared by the method of the present invention shows enhanced catalytic activity and it also results in decreasing quantities of fine particles or low polymers produced. Furthermore, polymers produced using the catalyst component of the present invention have a narrow particle size distribution, which results in improvement of polymer flowability during the polymerization process.

Full Text

TECHNICAL FIELD
The present invention relates generally to a method for preparing a catalyst component for ethylene polymerization and copolymerization. The present invention also relates generally to a catalyst or catalytic system comprising catalyst components prepared by the method of the present invention and an organometallic compound.

BACKGROUND OF THE INVENTION
In recent years, many research projects have been conducted in the field to develop various methods and catalysts for improving the physical properties of polyolefin polymers.
In particular, researchers are interested in finding techniques for reducing the amount of fine particles of polyolefin polymer. Reduction of the amount of fine particles is desirable for a number of reasons. Exemplary reasons include inhibiting the formation of deposits during the polymerization and preventing scattering of fine particles of polymer outside of the system. Furthermore, separation and filtration of the polymer slurry is easier due to a narrower particle size distribution. In addition, the drying efficiency is enhanced due to the improvement in polymer fluidity.
Japanese application 59-118120 discloses the production of polymer having a low amount of fine particles by utilizing a catalyst system that includes a mixture of an ingredient obtained from the reaction of magnesium, titanium, organoaluminum, silicon and halogenated aluminum compounds in sequence and a catalyst ingredient which is an organometallic compound. WO92/07008 discloses a method of manufacturing a polyolefin using a catalyst system of an ingredient (A) and an ingredient (B) wherein the ingredient (A) is prepared from a metallic magnesium or an oxygen-containing organic compound of magnesium, a mixture of a monohydroxylated organic compound and a polyhydroxylated organic compound, oxygen-containing organic compounds of titanium, halogenated aluminum compound, silicon compound and ingredient B is an organometallic compound of metals from Group Ia, IIa, IIIa or IVa of the Periodic Table. Although the method disclosed by the above-mentioned patent applications may produce polymer with small amount of fine particles, these methods are complicated.
Therefore, there is a demand for catalyst for polymerization and copolymerization of ethylene which can be prepared by a simple process, with high polymerization activity and an ability to facilitate production of polymers with narrow particle size distribution and small amount of fine particles.

SUMMARY OF THE INVENTION
The present invention is a method for preparing a catalyst component for at least one of polymerization and copolymerization of ethylene comprising the following steps of (i) reacting a magnesium solution with a liquid titanium compound having at least one alkoxy group to form a slurry product, (ii) contacting the slurry product with a liquid titanium halide compound to produce a contact product, (iii) elevating the temperature of the contact product to a temperature of 110°C to 130° C, (iv) maintaining the contact product at this temperature until a solid catalyst component is formed, and (v) washing the solid catalyst component with a halogenated hydrocarbon solution, wherein the solid catalyst component comprises at least one of titanium, magnesium and silicon.

DETAILED DESCRIPTION
The present invention provides a method for preparing a catalyst component for ethylene polymerization and copolymerization. The catalyst component of the present invention has a higher catalytic activity than previously disclosed or existing catalysts and also results in a decreased formation of fine particles or low polymers. Furthermore, polymers produced by the method of the present invention have a narrow particle size distribution, which results in improvement of polymer flowability during the polymerization process.
The meaning and scope of the term “polymerization” used herein is not limited to “homopolymerization”, but also includes “copolymerization” or “heteropolymerization”. Likewise, the meaning or scope of the term “polymer” used herein is not only limited to “homopolymer”, but also includes “copolymer” or “heteropolymer”.
Each ingredient, element or compound used for preparing a catalyst component provided by the invention is described below.

(a) Magnesium compound
In the preparation of the catalyst or catalyst component provided by the present invention, a magnesium compound is used. Preferably, the magnesium compound is used in a liquid state (and can be referred to as a magnesium solution). This is preferably achieved by dissolving a solid magnesium compound with an electron donor compound such as alcohols.
Preferably, the magnesium compound is a halogenated magnesium compound. Preferably, the halogenated magnesium compound is dissolved in an alcohol. More preferably, the halogenated magnesium compound is a dihalogen magnesium compound dissolved in an aliphatic alcohol.
Halogenated magnesium compounds used in this invention include, but are not limited to, the following; dihalogenated magnesium compound such as magnesium chloride, magnesium iodide, magnesium fluoride and magnesium bromide; alkyl magnesium halide compound such as methylmagnesium halide, ethylmagnesium halide, propylmagnesium halide, butylmagnesium halide, and amylmagnesium halide; alkoxymagnesium halide compound such as methoxymagnesium halide, ethoxymagnesium halide, isopropoxymagnesium halide and butoxymagnesium halide. These halogenated magnesium compounds can be used singularly or in combination (as a mixture of two or more halogenated magnesium compounds). Moreover, the above halogenated magnesium compounds can be effectively used in the form of a complex compound comprising other metals such as aluminum zinc, boron, sodium and potassium. Alternatively, the halogenated magnesium compound may be mixed with one or more of the above-listed metals.
The magnesium compounds or halogenated magnesium compounds used for preparing the catalyst component of the present invention also comprise alternative compounds that cannot be represented by a chemical formula. This may occur depending on production methods of such magnesium compounds. Alternative compounds may generally be referred to as mixtures of magnesium compounds. For example,the alternative compound or mixture of magnesium compounds may be obtained by reacting the magnesium compound with siloxane compounds or with silane compounds comprising a halogen, an ester or an alcohol. The alternative compound or mixture of magnesium compounds may also be obtained by reacting magnesium metal with an alcohol, a phenol or an ether in the presence of a halosilane, phosphorus pentachloride, or thionylchloride.
The magnesium compound provided by this invention may generally be represented by the following formula:
XnMgR2-n
Wherein n is a number of 0 = n (b) Liquid titanium compound having at least one alkoxy group
A titanium compound that has at least one alkoxy group can be
represented by the following formula:
Ti(OR)nX4-n
wherein n is a number between and including 1 and 4; R is a hydrocarbon group comprising between and including 1 and 20 carbon atoms; and X is a halogen atom.
For example, R in the above formula can be alkyl group such as methyl,
ethyl, propyl, isopropyl, butyl, isobutyl, tert-butyl, amyl, isoamyl; aryl groups such as phenyl, cresyl, xylyl and naphtyl groups; allyl groups such as propenyl group; and aralkyl groups such as benzyl group. Among them, alkyl groups comprising 2 to 10 carbon atoms or aryl groups having 6 to 10 carbon atoms are preferable, and straight chain alkyl groups comprising 2 to 10 carbon atoms are particularly preferable. The titanium compound represented by the above formula may have two or more different -OR groups.
The halogen atom or “X” in the formula at (b) (or for the liquid titanium compound) as shown above is for example, a chlorine atom, a bromide atom or an iodine atom. Of these examples of halogen atoms, the chlorine atom is particularly preferred. Preferably “n” in the formula at (b) (or for the titanium compound) as shown above is a number between and including 2 and 4, and 4 is particularly preferred.
Exemplary titanium compounds having at least one alkoxy group, and that are represented by the above formula include but are not limited to: hydrocarbyloxytitanium trihalides such as methoxyltitanium trichloride, ethoxytitanium trichloride and butoxytitanium trichloride; dihydrocarbyloxytitanium dihalides such as dimethoxytitanium dichloride, diethoxytitanium dichloride and dibutoxytitanium dichloride; trihydrocarbyloxytitanium monohalides such as trimethoxytitanium chloride, triethoxytitanium chloride, and tribuyoxytitanium chloride; and tetrahydrocarbyloxytitanium compounds such as tetramethoxytitanium, tetraethoxytitanium, and tetrabutoxytitanium. Particularly preferred titanium compounds are tetrahydrocarbyloxytitanium compounds, and more preferably tetrabutoxytitanium.
Preferably 0.05 to 0.40 mole of the liquid titanium compound is used with or for one mole of the magnesium compound. More preferably, 0.10 to 0.30 mole of the liquid titanium compound is used with or for one mole of the magnesium compound.
(c) Liquid titanium halide compound
The liquid titanium halide compound provided by the present invention is preferably a tetrahalogenated titanium compound. The tetrahalogenated titanium is for example titanium tetrachloride, titanium tetra bromide and titanium tetra iodide. A mixture of the above examples of tetrahalogenated titanium compounds may also be used. In this invention, the liquid titanium halide compound may be a singular or a combination of the above-listed exemplary tetrahalogenated titanium compounds. Preferably, the liquid titanium halide compound is titanium tetrachloride.
Preferably 0.1 to 100 mole of the liquid titanium halide is used with or for one mole of the magnesium compound. More preferably, 3 to 40 mole of the liquid titanium halide is used with or for one mole of the magnesium compound.
(d) Organosilicon compound comprising no active hydrogen
An organosilicon compound comprising no active hydrogen according to this invention can be represented by the general formula of
R1aR2bR3cR4dSi (OR5) e
wherein each R1, R2, R3, R4, and R5 is a hydrocarbon comprising 1 to 12 carbon atoms. Each of R1, R2, R3, R4, and R5 may be the same or different from each other, and a, b, c, d, e are integers between and including 0 and 4, and satisfy the formula a+b+c+d+e=4. The organosilicon compound is for example: dimethyldimethoxysilane, dimethyldiethoxysilane, diphenyldimethoxysilane, methylphenyldimethoxy silane, diphenyldiethoxysilane, methyltrimethoxysilane, ethyltriethoxysilane, vinyltrimethoxysilane, phenyltrimethoxysilane, methyltriethoxysilane, ethyltriethoxysilane, vinyltriethoxysilane, butyltriethoxysilane, phenyltriethylethoxysilane, ethyltripropoxysilane, phenyltriethoxysilane, ethylsilicate, butylsilicate, tetramethoxysilane, tetraethoxysilane, or tetrabutoxysilane.
Preferably 0.1 to 3 mole of the organosilicon compound is used with or for one mole of the magnesium compound. More preferably, 0.2 to 1.5 mole of the organosilicon compound is used with or for one mole of the magnesium compound.

(e) Other ingredients/elements used for preparing the catalyst component
As previously described, the magnesium compound is preferably in the liquid state, and can be referred to as a magnesium solution. Preparation of a solution of the magnesium compound, comprises dissolving the magnesium compound by using the alcohol as a solvent, either in the presence or in the absence of a hydrocarbon solvent.
The hydrocarbon solvent is preferably a halogenated hydrocarbon solvent. The presence of the halogenated hydrocarbon solvent for dissolving the magnesium compound is preferred. Type of alcohol used include, but is not limited to, alcohols comprising between and including 1 and 20 carbon atoms, such as methanol, ethanol, propanol, butanol, pentanol, hexanol, octanol, decanol, dodecanol, bezylalcohol, phenylethyl alcohol, isopropyl benzyl alcohol and cyclohexanol. Alcohols comprising not more than 12 carbon atoms are more preferred.
As described above, other ingredients used for preparing the catalyst component provided by the present invention comprise hydrocarbon compounds and halogenated hydrocarbon compounds. The hydrocarbon compound is preferably used as a solvent medium. The hydrocarbon compound preferably comprises 1 to 20 carbon atoms. The hydrocarbon compound is for example, or may comprise one or more of, pentane, hexane, heptane, decane, isoparafin, dodecane, benzene toluene or xylene. Halogenated hydrocarbons are also preferably used for preparing the magnesium solution as a solvent medium. The halogenated hydrocarbons comprises between and including 1 and 20 carbon atoms and at least one halogen atom ligand. The halogenated hydrocarbon may comprise one or more of, monochloromethane, dichloromethane, trichloromethane, tetrachloromethane, monochloroethane, 1,2-dichloroethane, monochloropropane, monochlorobutane, monobromopropane, monodiodomethane, or monoiodomethane. Preferably, the halogenated hydrocarbon comprises at least one chloride atom.

Preparation of catalyst component
The catalyst component for ethylene polymerization and copolymerization as provided by the present invention can be prepared by a method comprising the following steps:
(i) Reacting the magnesium solution with the liquid titanium compound, the liquid titanium compound comprising at least one alkoxy group, to form a slurry product;
(ii) Contacting the slurry product formed in step (i) and the liquid titanium halide to produce a contact product;
(iii) Elevating the temperature of the contact product produced in step (ii) to a temperature between and including 110°C to 130°C. The contact product is then maintained at this temperature until a solid particle of the catalyst component is formed. During the elevation of the temperature of the contact product, an organosilicon compound having no active hydrogen is added to the contact product; and
(iv) Washing the solid particle of catalyst component with a halogenated hydrocarbon solution.

In the step (i), the reaction between the magnesium solution and the liquid titanium compound comprising at least one alkoxy group is carried out at a controlled temperature in order to control shape and particle size distribution of the slurry product formed. The temperature is also controlled for forming a good shape of the slurry product as required. Preferably the reaction is carried out at a temperature between and including 0°C and 70°C. More preferably, the reaction is carried out at a temperature between 20°C and 50°C. The reaction between the magnesium solution with the liquid titanium compound occurs over a duration of approximately 0.5 hours to 3 hours to complete the reaction and form the slurry product. The slurry product preferably has an average particle size of smaller than 1 micron.

The slurry product obtained from this step is further reacted with the
liquid titanium halide compound in the step (ii) to form the contact product at a predetermined temperature of between and including -50°C to 50°C, or more preferably between -20°C to 20°C. In order to complete the reaction between the slurry product and the liquid titanium halide compound of step (ii), and to result a good shape and particle size distribution of the contact product, step (ii) preferably occurs over a duration of about 0.5 hours to 3 hours.
In order to increase quality of the formed catalyst component in term of morphology, particle size distribution and catalytic activity, the contact product is preferably further reacted with the organosilicon compound, which comprises no active hydrogen, at a temperature between and including 20°C and 80°C to form the solid particle of catalyst component. More preferably, the contact product is further reacted with the organosilicon compound at a temperature between and including 40°C and 60°C to form the solid particle of catalyst component. The organosilicon compound comprising no active hydrogen used in this reaction may be one of the exemplary organosilicon compounds described above, or a combination of two or more different exemplary organosilicon compounds. After the addition of the organosilicon compound comprising no active hydrogen, the temperature is raised up to between and including 110°C to 130°C, over a duration of about 0.5 hours to 3 hours, in order to completely form the solid catalyst component. The formed solid catalyst component is then further washed with the halogenated hydrocarbon solution.
Alternatively, the formed solid catalyst component may further react with the liquid titanium halide compound before being washed with the halogenated hydrocarbon solution in the step (iv). The liquid titanium halide compound may be used in isolation. Alternatively, the liquid titanium halide may be used in combination with one or more of the exemplary halogenated hydrocarbons as listed above. Preferably, the liquid titanium halide compound used in the step (ii) is titanium tetrachloride. The solid catalyst component obtained by the above-described method preferably comprises magnesium, titanium, halogen and silicon.

Ethylene Polymerization
The solid catalyst component (also known as the catalyst component) produced by the above method can be used for polymerization of ethylene. Preferably, the catalyst component can be used for homopolymerization of ethylene. Further preferably, the catalyst component can also be used for copolymerization of ethylene and alpha-olefins, which have three or more carbon atoms, such as propylene, 1-butene, 1-pentene or 1-hexene.
The polymerization reaction using the catalyst component prepared by
the method provided by the present invention may be carried out by using a catalyst system. The catalyst system comprises the catalyst component prepared as described above. The catalyst component preferably comprises at least one of magnesium, titanium, halogen, and silicon. The catalyst system preferably further comprises organometallic compounds that comprise at least one metal selected from Group II or Group III of the Periodic Table.
The organometallic compound may be represented by a formula of
MRn
wherein “M” is a metal selected from Group II or Group III of the Periodic Table, such as magnesium, calcium, zinc, boron, aluminum, or gallium, “R” is an alkyl group comprising 1 to 10 carbon atoms, such as a methyl, ethyl, butyl, hexyl, or octyl, and “n” is the atomic valence of the selected metal. Preferably, the organometallic compound is trialkylaluminum, which comprises an alkyl group of 1 to 8 carbon atoms, such as triethylaluminum, triisobutylaluminum, and trioctylaluminum. Alternatively, the organometallic compound comprises a mixture of trialkylaluminums. Further alternatively, the organometallic compound is an organoaluminum comprising one or more halogens or hydride groups. Examples of organoaluminums include, but are not limited to, ethylaluminum dichloride, diethylaluminum chloride, ethylaluminum sesquichloride and diisobutylaluminum hydride.

Pre-polymerization Reaction/Process
The catalyst component obtained from the above preparation may be pre-polymerized with ethylene or alpha-olefin before their use in the polymerization reaction. The pre-polymerization of the catalyst component with ethylene or alpha-olefin may be carried out in the presence of a hydrocarbon solvent, for example hexane or pentane, at predetermined temperature. In addition, the pre-polymerization of the catalyst component with ethylene or alpha-olefin is preferably performed under a predetermined pressure, and in the presence of the organoaluminum compound, for example triethylaluminum. In order to acquire a required shape and an enhanced mechanical strength of the catalyst component for thereby forming the ethylene or alpha-olefin polymer over the catalyst component, a weight of alpha-olefin to that of the catalyst component after the pre-polymerization is preferably approximately 0.1 to 20.
The polymerization reaction as provided by the present invention, which utilizes the catalyst component, is preferably performed at a predetermined polymerization temperature of between and including 20°C and 300°C. More preferably, the polymerization reaction is performed at a polymerization temperature of between and including 50°C to 150°C. In addition, the polymerization reaction is preferably performed at an operating pressure of not more than 100 bar, and more preferably at between and including 2 and 50 bar.
When hydrogen is used in the polymerization reaction, average molecular weight and molecular weight distribution of polymer produced by the polymerization reaction (i.e. product of the polymerization reaction) may be changed.
The polymerization reaction may be performed by gas phase polymerization or bulk phase polymerization in the absence of an organic solvent. Alternatively, the polymerization reaction may be performed by liquid slurry polymerization in the presence of an organic solvent. These polymerization reactions are preferably performed in the absence of oxygen, water, and other catalytic poison compounds.
The polymer produced by the polymerization reaction that uses the catalyst component provided by the present invention preferably has an enhanced shape. Moreover the polymer produced by the polymerization reaction that uses the catalyst component provided by the present invention preferably are not adversely affected, and also do not melt on reactor walls. This is preferably because of reduced quantity of fine particles or low polymers, and an enhanced flowability of the produced polymer particles.
For liquid slurry polymerization, the catalyst component used for the polymerization reaction preferably comprises approximately 0.0001 mmol to 5 mmol of titanium atom per one liter of solvent used. In addition, preferably approximately 1 to 2,000 mole of organometallic material is used per one mole of titanium atom of the catalyst component used for the polymerization reaction. As described above, a hydrocarbon solvent comprising one or more hydrocarbon compounds as listed above, for example pentane, hexane, heptane, octane, isoparafin, toluene, benzene, xylene, cyclohexane is preferably used for the polymerization reaction.
Polyethylene produced by the polymerization reaction using the solid catalyst component provided by the present invention preferably has a bulk density between and including 0.20 g/cm3 and 0.60 g/cm3, and more preferably between 0.25 g/cm3 and 0.60 g/cm3, as well as a melt flow index (ASTM D1238E) between and including 0.01 g/10min and 5000 g/10min.
Furthermore, additives including, but not limited to, heat stabilizers, weathering stabilizers, antistatic agents, antiblocking agents, lubricants, nucleating agents, pigments, dyes and inorganic and organic fillers may be further added as according to commercial requirements.
The characteristics of the produced polymer by the polymerization process provided by the present invention, for example melt flow rate, particle size distribution, and the bulk density, are investigated by methods or techniques known in the art as described below. For example:
a) Melt Flow Rate (MFR) of polymer particles is determined by using the method according to ASTM-1238.
b) Polymer particle size distribution is analyzed by utilizing RETSCH AS-200 device.
c) Bulk density of polymer is determined by using the method according to ASTM-D1859-89.

EXAMPLE
The following examples are included to illustrate exemplary embodiments of the present invention. The following examples do not define or limit the scope of the present invention.
It should be appreciated by those of skill in the art that the techniques disclosed in the following examples represent exemplary embodiments of techniques and processes provided by the present invention. It will however be appreciated by those of skill in the art, in light of the present disclosure, that changes can be made to the exemplary embodiments and still obtain a like or similar result without departing from the spirit and scope of the present invention.

Example 1
Preparation of a solid particle catalyst
(1) Preparation of a magnesium solution /homogenous solution
Reactants, namely 10 g (0.105 mol) of MgCl2, 100 ml of decane, 12 ml of 1,2-dichloroethane, and 51 ml (0.325 mol) of 2-ethylhexyl alcohol were introduced into a volumetric flask of 1 Liter. The volumetric flask comprised a magnetic stirrer therewithin and was blanked with a nitrogen atmosphere. The reactants were mixed by the magnetic stirrer at a stirring speed of 300 rpm, and heated to 130°C, for 3 hours to produce a homogeneous solution or a magnesium solution. The homogenous solution was then cooled to a temperature of 50°C. After the homogenous solution was cooled to 50°C, 12.5 ml (0.037mol) of titanium butoxide was added into the homogenous solution. Mixture of the homogenous solution and titanium butoxide was then stirred at 50°C for 2 hours to produce or obtain a slurry product.
(2) 51 ml (0.47mol) of TiCl4 was dripped into the above slurry product, which was cooled down to 0°C over a time period of 1 hour with stirring. After the addition of TiCl4 into the slurry product was completed, the temperature was maintained at 0°C for a further 1 hour to form a solid product. The solid product is also known as the catalytic component.
(3) The temperature of the above reactants in (1) and (2) was then elevated from 0°C to 50°C over a period of 1 hour. 3 ml (0.27 mol) of tetraethylorthosilicate was added to the above reactants to form a mixture. The temperature of the mixture was then raised to 110°C over a period of 1 hour. The temperature of the mixture was then maintained at 110°C for 2 hours with stirring.
(4) After completion of the steps (1) to (3), the solid product was separated by hot decanter. The solid product is then treated with 200 ml of 1,2-dichloroethane. The decanted solid product was also sufficiently washed with hexane and decane at 100°C until no trace of titanium component in the supernatant was found.
The atomic molar-ratio of titanium to magnesium in the obtained catalyst component was 0.21.

Ethylene Polymerization
A 2 liter stainless steel reactor equipped with a mechanical stirrer and an advanced temperature controller system was purged with nitrogen atmosphere. 500 ml of hexane was introduced into the reactor. 3 atm of hydrogen was then added after an introduction of 1 mmol of triethylaluminum and the solid catalyst component comprising 0.003 mol of titanium atom. The temperature of the reactor was increased to 80°C. Stirring speed of the mechanical stirrer was set at 500 rpm. Ethylene was added into the reactor and the pressure of ethylene within the reactor was set at 8 atm. The polymerization of ethylene (i.e. polymerization reaction) was performed for 2 hours. After the polymerization reaction, the temperature of the reactor was reduced to room temperature, and the pressure within the reactor was released. A predetermined amount of ethanol was introduced into the reactor to stop the polymerization reaction. Produced ethylene polymer was collected, and dried in a vacuum oven at 50°C for at least 3 hours to obtain a free-flow polyethylene powder.
The polyethylene powder was obtained in a yield of 369 g (or 61.57
kgPE/mmolTi), has a MFR (i.e. melt flow rate) of 0.55 g/10min, and has an apparent bulk specific gravity of 0.31 g/cc. Particle size distribution of the polyethylene powder is shown in Table 2.

Example 2
A catalyst component was prepared in the same procedures as in Example 1, except that 12.5 ml of titanium butoxide was not introduced into the magnesium solution in step (1). The atomic molar-ratio of titanium to magnesium in the obtained catalyst was 0.15. Ethylene polymerization (i.e. polymerization reaction) was carried out as according to the steps described in Example 1.
Polymer of Example 2 was obtained in a yield of 355 g (or 59.24 kgPE/mmolTi), has a MFR (i.e. melt flow rate) of 0.30 g/10min, and has an apparent bulk specific gravity of 0.31 g/cc. Particle size distribution of the resulting Polyethylene powder of Example 2 is shown in Table 2.

Example 3
A catalyst component was prepared in the same procedures as in Example 1, except that 3 ml of tetraethylorthosilicate was not introduced to the contact product in step (3). The atomic molar-ratio of titanium to magnesium in the obtained catalyst component was 0.18. Polymerization of ethylene (i.e. polymerization reaction) was carried out according to the steps described in Example 1. The polymer was obtained in a yield of 220 g (or 36.74 kgPE/mmolTi), has a MFR (i.e. melt flow rate) of 0.28 g/10min, and an apparent bulk specific gravity of 0.30 g/cc. Particle size distribution of the resulting polyethylene powder is shown in Table 2.

Example 4
A catalyst component was prepared in the same procedures as in Example 1, except that 200 ml of 1,2-dichloroethane was not introduced to treat the solid product produced in step (4). The atomic molar-ratio of titanium to magnesium in the obtained catalyst was 0.20. Polymerization of ethylene (i.e. polymerization reaction) was carried out according to the steps described in Example 1. The polyethylene powder was obtained in a yield of 344 g (or 57.32 kgPE/mmolTi), has a MFR (i.e. melt flow rate) of 0.26 g/10min and an apparent bulk specific gravity of 0.21 g/cc. Particle size distribution of the resulting polyethylene powder is shown in Table 2.

Example 5
A catalyst component was prepared in the same procedures as in Example 1, except that the 3 ml of tetraethylorthosilicate introduced to the contact product in step (3) was replaced by 2.5 ml of tributylphosphate. The atomic molar-ratio of titanium to magnesium in the obtained catalyst was 0.23. Polymerization of ethylene (i.e. polymerization reaction) was carried out according to the steps described in Example 1. The polyethylene powder or polymer was obtained in a yield of 204 g (or 34.13 kgPE/mmolTi), has a MFR (i.e. melt flow rate) of 0.77 g/10min and an apparent bulk specific gravity of 0.30 g/cc. Particle size distribution of the resulting polyethylene powder is shown in Table 2.

Example 6
A catalyst component was prepared in the same procedures as in Example 1, except that 200 ml of TiCl4 was introduced to the solid product before treating the solid product with 1,2-dichloroethane upon completion of the step (3). The atomic molar-ratio of titanium to magnesium in the obtained catalyst was 0.20. Polymerization of ethylene (i.e. polymerization reaction) was carried out according to the steps described in Example 1. The polyethylene powder or polymer was obtained in a yield of 343 g (or 57.32 kgPE/mmolTi), has a MFR (i.e. melt flow rate) of 0.51 g/10min, and an apparent bulk specific gravity of 0.28 g/cc. Particle size distribution of the resulting polyethylene powder is shown in Table 2.

Example 7
A catalyst component was prepared in the same procedures as in Example 1, except that 5 ml (0.45mol) of tetraethylorthosilicate was introduced to the contact product in step (3). The atomic molar-ratio of titanium to magnesium in the obtained catalyst was 0.19. Polymerization of ethylene (i.e. polymerization reaction) was carried out according to the steps described in Example 1. The polymer was obtained in a yield of 357 g (or 59.61 kgPE/mmolTi), has a MFR (i.e. melt flow rate) of 0.25 g/10min, and an apparent bulk specific gravity of 0.30 g/cc. Particle size distribution of the resulting polyethylene powder is shown in Table 2.

Example 8
A catalyst component was prepared in the same procedures as in Example 1, except that 25 ml (0.074mol) of titanium butoxide was introduced into magnesium solution in step (1). The atomic molar-ratio of titanium to magnesium in the obtained catalyst was 0.23. Polymerization of ethylene (i.e. polymerization reaction) was carried out according to the steps described in Example 1. The polymer was obtained in a yield of 245 g (or 40.88 kgPE/mmolTi), has a MFR (i.e. melt flow rate) of 0.28 g/10min, and an apparent bulk specific gravity of 0.28 g/cc. Particle size distribution of the resulting polyethylene powder is shown in Table 2.

Existing Method
Preparation of a solid particle catalyst
In a 1 liter glass reactor, 10 g (0.105 mol) of MgCl2 was suspended in 300 ml of hexane. To the suspension of MgCl2 and hexane, 42 ml (0.714 mol) of ethanol was introduced over a period of 1 hour. Temperature of the suspension of MgCl2 and hexane is controlled at 20°C with stirring. Reaction between the MgCl2 and hexane occurs during the stirring for another 1 hour at 20°C. 85 gram (0.315 mol) of diethylaluminum chloride was then dropped or introduced into the suspension of MgCl2 and hexane to form a mixture, which is maintained at a temperature of at 20°C for one more hour with stirring. Next, 40.3 ml (0.368) of TiCl4 was slowly added into the mixture at 30°C with stirring. The temperature was raised to 80°C over a period of 2 hours and a catalyst is produced.
After the reaction was completed, a solid catalyst was separated from the mixture, which is at a liquid phase, at room temperature. The solid product was sufficiently washed with hexane until no titanium component in the supernatant was found. The final solid catalyst was obtained in the form of a suspended solid catalyst in a hexane solvent. The atomic molar-ratio of titanium to magnesium in the obtained catalyst was 0.13.
Polymerization of ethylene (i.e. polymerization reaction) was carried out according to the steps described in Example 1. The polyethylene powder or polymer was obtained in a yield of 268 g (or 44.77 kgPE/mmolTi), has a MFR (i.e. melt flow rate) of 0.26 g/10min, and an apparent bulk specific gravity of 0.30 g/cc. Particle size distribution of the resulting polyethylene powder is shown in Table 2.

Table 1
Example Catalytic activity
(kgPE/mmolTi) Bulk specific gravity (g/cm3) MFR
(g/10min)
1 61.57 0.31 0.55
2 59.23 0.31 0.30
3 36.74 0.30 0.28
4 57.32 0.21 0.26
5 34.13 0.30 0.77
6 57.32 0.28 0.51
7 59.61 0.30 0.25
8 40.88 0.28 0.28
Existing Method 44.77 0.30 0.26

Table 2
Example Particle size distribution
>500µm >250µm >180µm >106µm >75µm >45µm
1 4.8 16.9 59.4 16.4 1.1 1.0
2 5.3 48.6 27.8 15.7 2.1 0.4
3 4.6 7.9 24.9 51.7 7.5 3.3
4 2.4 68.2 22.3 5.5 1.0 0.6
5 27.6 17.1 11.3 20.2 13.6 8.3
6 2.4 68.2 22.3 5.5 1.0 0.6
7 3.6 33.1 40.9 16.7 3.9 1.8
8 2.5 20.1 38.6 32.2 5.1 1.4
Existing Method 20.6 10.5 12.1 29.2 16.3 9.6

As shown in the above tables, the catalytic activity of the catalytic component provided by the present invention can have an enhanced catalytic activity (kgPE/mmolTi) as compared with the catalytic activity of the catalyst of the existing method. In addition, the MFR (g/10min) of the polymer produced by the polymerization reaction using the catalytic component provided by the present invention can be higher than that of the polymer of the existing method. Furthermore, particle size distribution of polymers produced by the polymerization reaction using the catalytic component provided by the present invention can be narrowed.

We Claim:

1. A method of preparing a catalyst component for at least one of polymerization and copolymerization of ethylene comprising:
(i) reacting a magnesium solution with a liquid titanium compound having at least one alkoxy group to form a slurry product,
(ii) contacting the slurry product with a liquid titanium halide compound for producing a contact product;
(iii) elevating temperature of the contact product to a temperature of between and including 110°C and 130°C;
(iv) maintaining the contact product at the temperature for forming a solid catalyst component; and
(v) washing the solid catalyst component with a halogenated hydrocarbon solution,
wherein the solid catalyst component comprises at least one of titanium, magnesium and silicon.

2. The method as in claim 1, further comprising:
adding an organosilicon compound having no active hydrogen to the contact product during elevating of the temperature in the step (iii).

3. The method of claim 1, further comprising:
treating the solid catalyst component with an additional liquid titanium compound, wherein the treating of the solid catalyst component occurs before washing the solid catalyst component with the halogenated hydrocarbon solution in the step (v).

4. The method of claim 1, wherein the liquid titanium compound comprising at least one alkoxy group is represented by a formula of Ti(OR)nX4-n, and wherein n is a number between and including 1 and 4; R is a hydrocarbon group comprising between and including 1 and 20 carbon atoms; and X is a halogen atom.

5. The method of claim 1, wherein the liquid titanium halide compound is a tetrahalogenated titanium or a mixture of the tetrahalogenated titanium with a titanium compound comprising at least one alkoxy group.

6. The method of claim 1, wherein the organosilicon compound is a compound represented by a formula R1aR2bR3cR4dSi (OR5)e, and wherein each of R1, R2, R3, R4, and R5 is a hydrocarbon comprising between and including 1 and 12 carbon atoms, each of R1, R2, R3, R4 and R5 being one of the same and different from each other, and a, b, c, d, e are integers between 0 and 4.

7. The method of claim 1, wherein the molar ratio of the liquid titanium compound comprising at least one alkoxy group to the magnesium solution is approximately between and including 0.05 mole and 0.40 mole per one mole of the magnesium solution.

8. The method of claim 1, wherein the reaction between the magnesium solution and the liquid titanium compound having at least one alkoxy group is carried out at a temperature of between and including 0°C to 70°C.

9. The method of claim 1, wherein the amount of the liquid titanium halide compound is approximately between and including 0.1 mole and 100 mole per one mole of the magnesium solution.

10. The method of claim 1, wherein the contacting reaction between the slurry product and the liquid titanium halide compound is carried out at the temperature of between and including -50°C and 50°C.

11. The method of claim 2, wherein the amount of the organosilicon compound comprising no active hydrogen is approximately between and including 0.1 mole to 3 mole per one mole of the magnesium solution.

12. The method of claim 2, wherein the organosilicon compound comprising no active hydrogen is added to the contact product at a temperature of between and including 20°C and 80°C.

13. A catalyst system for at least one of polymerization and copolymerization of ethylene comprising:
(a) the catalyst component as claimed in any one of claim 1 to 12; and
(b) an organometallic compound comprising at least one metal selected from Group II and Group III of the Periodic Table.

14. An ethylene polymerization process comprising polymerizing ethylene in the presence of the catalyst system as claimed in claim 13.

15. An ethylene copolymerization process comprising copolymerizing ethylene and at least one of a comonomer and a polymer in the presence of the catalyst system as claimed in claim 13.

Dated this 22nd day of December, 2008

[GOUTAM BHATTACHARYYA]
OF K & S PARTNERS
ATTORNEY FOR THE APPLICANT(S)

ABSTRACT

Method for Preparing a Catalyst Component for Ethylene Polymerization and Copolymerization

The present invention discloses a method for preparing a catalyst component for polymerization and copolymerization of ethylene. The method comprises a step of reacting a magnesium solution with a liquid titanium compound having at least one alkoxy group to form a slurry product. The method further comprises contacting the slurry product with a liquid titanium halide compound to produce a contact product, elevating temperature of the contact product to a temperature between and including 110°C and 130°C, and maintaining the contact product at this temperature until a solid catalyst component is formed. During elevation of the temperature of the contact product, an organosilicon compound having no active hydrogen is added to the contact product. The solid catalyst component is washed with a halogenated hydrocarbon solution. Furthermore, the solid catalyst component can be treated at least once with an additional liquid titanium compound having at least one halogen ligand before washing with the halogenated hydrocarbon solution.
The catalyst component prepared by the method of the present invention shows enhanced catalytic activity and it also results in decreasing quantities of fine particles or low polymers produced. Furthermore, polymers produced using the catalyst component of the present invention have a narrow particle size distribution, which results in improvement of polymer flowability during the polymerization process.

Documents:

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Patent Number

272518

Indian Patent Application Number

2658/MUM/2008

PG Journal Number

15/2016

Publication Date

08-Apr-2016

Grant Date

05-Apr-2016

Date of Filing

22-Dec-2008

Name of Patentee

SCG CHEMICALS CO. LTD.

Applicant Address

1 Siam Cement Road Bangsue Bangkok 10800 Thailand

Inventors:

#	Inventor's Name	Inventor's Address
1	CHAROENCHAIDET Sumate	80/4 Moo 4 Bangchak Paseecharoen Bangkok 10160 Thailand

PCT International Classification Number

C08F4/632

PCT International Application Number

N/A

PCT International Filing date

PCT Conventions:

#	PCT Application Number	Date of Convention	Priority Country
1	TH 0701006626	2007-12-21	Thailand