RU2153509C2 - Solid titanium catalyst component, ethylene polymerization component comprising said component, and method of ethylene polymerization - Google Patents

Abstract

FIELD: chemical industry. SUBSTANCE: method comprises contacting (a) liquid magnesium compound with (b) liquid titanium compound in the presence of organosilicon compound having inactive hydrogen in amount from 0.25 to 0.35 mole per 1 mole of magnesium compound (a), raising the resulting contact purging (i) temperature to 105-115 C and maintaining contact product at above-mentioned temperature. Contact product is then brought into contact with not more than 0.5 mole of organosilicon compound having inactive hydrogen (c). Also described is ethylene polymerization catalyst prepared from solid catalyst component and organometallic compound, and polymerization method using said catalyst. In using solid titanium catalyst component, ethylene is polymerized with high activities and ethylene polymer having superb particle properties is obtained. EFFECT: more efficient ethylene polymerization method. 5 cl, 1 dwg, 7 ex, 10 com. ex, 5 tbl

Description

 The invention relates to a solid titanium catalytic component capable of polymerizing high activity ethylene and producing a polymer with excellent particle properties, and also relates to an ethylene polymerization catalyst containing a solid titanium catalyst component, and a method for polymerizing ethylene using this catalyst.

 Ethylene polymers such as homopolyethylene and linear low density polyethylene (LLDPE) are widely used for films due to their excellent transparency and mechanical strength.

 Various methods for producing ethylene polymers have been commonly proposed, and it is known that ethylene polymers can be prepared with high polymerization activity when a Ziegler catalyst comprising titanium, magnesium, halogen and optionally an electron donor compound is used as a catalyst for polymerization. It is also known that high activities are manifested especially when a solid titanium catalyst component obtained from a halogen-containing magnesium compound in a liquid state, a liquid titanium compound and an electron-donating compound are used as a titanium catalyst component.

 In these methods for producing ethylene polymers, if the polymer is polymerized with higher activities, not only productivity increases, but also the amount of catalyst residues per polymer unit, especially the halogen content, decreases, so that the problem of mold rusting in molding processes can be solved.

 Therefore, it is desirable to provide a solid titanium component capable of polymerizing ethylene with higher activities.

 The ethylene polymers obtained immediately after polymerization are mainly in powder form, even if the polymerization was carried out by a suspension polymerization method or a gas-phase polymerization method, in which case it is desirable that the obtained ethylene polymers have good flowability, contain not finely ground powder, have an excellent distribution particle size. Ethylene polymers exhibiting such excellent particle properties have various advantages, for example, they can be used as such, depending on the purpose, even if they are not granular.

The purpose of the invention
The present invention has been made under the circumstances described above, and it is an object of the invention to provide a solid titanium catalyst component by which ethylene can be polymerized with high activities and an ethylene polymer with excellent particle properties can be obtained. Another object of the invention is to provide an ethylene polymerization catalyst containing a solid titanium catalyst component and a method for ethylene polymerization using a catalyst.

This objective of the claimed invention is achieved due to the fact that a solid titanium catalyst component for ethylene polymerization is obtained by a process comprising the step of: contacting (a) a liquid magnesium compound with (b) a liquid titanium compound in the presence of (c) an organosilicon compound having inactive hydrogen, and a stage raising the temperature of the obtained contact product (i) and keeping the contact product (i) at this temperature, said solid titanium catalyst component comprising th, titanium, halogen and an organosilicon compound having inactive hydrogen (c), wherein the contacting step is carried out at a molar ratio of organosilicon compound (c) to magnesium compound (a) equal to 0.25-0.35 mol per 1 mol magnesium compounds (a) and maintaining the resulting contact product (i) is carried out at 105-115 ^o C.

The technical effect is also achieved due to the fact that a solid titanium catalyst component for ethylene polymerization is obtained by a process comprising the step of: contacting (a) a liquid magnesium compound with (b) a liquid titanium compound in the presence of (c) an organosilicon compound having inactive hydrogen, and a step of increasing the temperature of the obtained contact product (i) and keeping it at a given temperature, said solid titanium catalyst component comprising magnesium, titanium, halogen and silicon organ a chemical compound having inactive hydrogen (s), wherein the contacting step is carried out at a molar ratio of the organosilicon compound (s) to the magnesium compound (a) equal to 0.25-0.35 mol per 1 mol of the magnesium compound (a), and maintaining the resulting contact product (i) is carried out at 105-115 ^o C with the addition of an organosilicon compound having inactive hydrogen (c) in an amount of not more than 0.5 mol per 1 mol of magnesium compound (a), and the contact temperature product (i) rises from a temperature below 10 ^o C, than the maintained temperature, to the temperature at which the temperature increase ends, or after the temperature increase ends, the compound (c) is contacted with the contact product (i), and also because the ethylene polymerization catalyst containing (I) a solid titanium catalytic component and (II) an organoaluminum compound, contains any of the above components as a solid titanium catalytic component, while in the method of polymerizing ethylene by polymerizing these Lena in the presence of a catalyst containing a solid titanium catalyst component and an organoaluminum compound, an ethylene polymerization catalyst containing (I) a solid titanium catalyst component and (II) an organoaluminum compound is used as a catalyst.

 The drawing shows the steps for preparing a solid titanium catalyst component according to the invention and shows the steps for preparing an ethylene polymerization catalyst according to the invention.

 DETAILED DESCRIPTION OF THE INVENTION.

 A solid titanium catalyst component, a polymer polymerization catalyst containing a catalyst component and an ethylene polymerization method according to the invention are described in detail below.

 The meaning of the term “polymerization” as used herein is not limited to “homopolymerization”, but may include “copolymerization”. Also, the meaning of the term “polymer” as used herein is not limited to “homopolymer”, but may include “copolymer”.

 The drawing shows the stages for producing a solid titanium catalytic component in accordance with the invention and the stages for producing an ethylene polymerization catalyst containing a catalytic component.

 [I] Solid titanium catalyst component.

 The solid titanium catalyst component according to the invention is obtained by bringing (a) a liquid magnesium compound, (b) a liquid titanium compound, and (c) an organosilicon compound having inactive hydrogen in a certain amount per 1 mol of magnesium compound (a) into contact with each other by the method described below, and includes magnesium, titanium, halogen, and an organosilicon compound having inactive hydrogen (c).

 First, each ingredient used to prepare the solid titanium catalyst component of the invention is described.

 (a) Liquid magnesium compound.

 To obtain a solid titanium catalyst component of the invention, the magnesium compound is used in a liquid state. When the magnesium compound is solid, it is made liquid before use. As the magnesium compound, any of (a-1) magnesium compound having reducing ability and (a-2) magnesium compound having no reducing ability can be used.

A magnesium compound having a reducing ability (a-1) means, for example, an organomagnesium compound represented by the following formula:
X _n MgR _2-n ,
where n means the number 0 ≤ n ≤ 2; R is hydrogen, an alkyl group of 1 to 20 carbon atoms, an aryl group or a cycloalkyl group; when n is 0, two Rs may be the same or different; and X is halogen.

Examples of organomagnesium compounds having a reducing ability include:
dialkyl magnesium compounds such as dimethyl magnesium, diethyl magnesium, dipropyl magnesium, dibutyl magnesium, diamyl magnesium, dihexyl magnesium, didecyl magnesium, octyl butyl magnesium and ethyl butyl magnesium;
alkyl magnesium halides such as ethyl magnesium chloride, propyl magnesium chloride, butyl magnesium chloride, hexyl magnesium chloride and amyl magnesium chloride;
alkyl magnesium alkoxides such as butylethoxy magnesium, ethyl butoxy magnesium and octyl butoxy magnesium; and
other compounds such as butyl magnesium hydride.

Examples of magnesium compounds having no reducing ability (a-2) include:
magnesium halides such as magnesium chloride, magnesium bromide, magnesium iodide and magnesium fluoride;
alkoxymagnesium halides such as methoxymagnesium chloride, ethoxymagnesium chloride, isopropoxymagnesium chloride, butoxymagnesium chloride and octoxymagnesium chloride;
ariloximagnesium halides such as phenoxy magnesium chloride and methyl phenoxy magnesium chloride,
alkoxymagnesium such as ethoxymagnesium, isopropoxymagnesium, butoxymagnesium, n-octoxymagnesium and 2-ethylhexoxy magnesium;
aryloxy magnesium such as phenoxy magnesium and dimethyl phenoxy magnesium;
magnesium carboxylates such as magnesium laurate and magnesium stearate;
magnesium metal; and
magnesium hydrides.

 Magnesium compounds having no reducing ability (a-2) can be compounds formed from the aforementioned magnesium compounds having reducing ability (a-1), or compounds formed during the process of obtaining the catalytic component. To obtain magnesium compounds having no reducing ability (a-2), from magnesium compounds having reducing ability (a-1), for example, magnesium compounds having reducing ability (a-1) are brought into contact with alcohols, ketones, esters, ethers, siloxane compounds, halogen-containing compounds such as halogen-containing silane compounds, halogen-containing aluminum compounds and acid halides, or compounds having an OH group or an active carbon-oxygen bond.

 In the present invention, magnesium compounds having no reducing ability (a-2) can be obtained from magnesium compounds having reducing ability (a-1) using the organosilicon compound having inactive hydrogen (c) described below.

 Magnesium compounds may be used in combination of two or more kinds.

 The magnesium compounds can form complex compounds or double compounds together with other organometallic compounds such as aluminum, zinc, boron, beryllium, sodium and potassium (for example, the organoaluminum compound described below), or can be mixed with these metal compounds.

 Other magnesium compounds than those described above can be used to prepare the solid titanium catalyst component [I], but it is preferable that the magnesium compound is present in the form of a halogen-containing magnesium compound in the final solid catalyst component [I]. Therefore, if a halogen-free magnesium compound is used, the magnesium compound is preferably contacted with the halogen-containing compound during the process of preparing the catalyst component.

 Of the above compounds, magnesium compounds having no reducing ability, especially those containing halogen, are preferred. Among them, magnesium chloride, alkoxymagnesium chloride and aryloxy magnesium chloride are most preferred.

 When the magnesium compound is solid, the solid magnesium compound can be made liquid using the electron donor compound (d-1).

 The electron donor compound (d-1) includes alcohols, carboxylic acids, aldehydes, amines, and metallic acid esters.

Examples of alcohols include:
aliphatic alcohols, such as methanol, ethanol, propanol, isopropyl alcohol, butanol, pentanol, hexanol, 2-methylpentanol, 2-ethylbutanol, heptanol, 2-ethylhexanol, octanol, decanol, dodecanol alcohol, tetradecyl alcohol alcohol, tetradecyl alcohol, stearyl alcohol and ethylene glycol;
alicyclic alcohols such as cyclohexanol and methylcyclohexanol;
aromatic alcohols, such as benzyl alcohol, methylbenzyl alcohol, isopropylbenzyl alcohol, α-methylbenzyl alcohol, α, α dimethylbenzyl alcohol, phenylethyl alcohol, cumyl alcohol, phenol, cresol, xylenol, ethylphenol, propylphenol and nonylphenol;
alcohols containing an alkoxy group such as n-butyl cellosolve, ethyl cellosolve, 1-butoxy-2-propanol and methylcarbitol; and
halogenated alcohols such as trichloromethanol, trichloethanol and trichlorohexanol.

 Carboxylic acids are preferred those having 7 or more carbon atoms, for example caprylic acid, ethylcaproic acid, pelargonic acid and undecylenic acid.

 Aldehydes are preferably those having 7 or more carbon atoms, for example, caprylaldehyde, 2-ethylhexylaldehyde, undecylaldehyde, benzaldehyde, toluene aldehyde and naphthoaldehyde.

 Amines are preferred those having 6 or more carbon atoms, for example heptylamine, octylamine, 2-ethylhexylamine, nonylamine, decylamine, undecylamine and laurylamine.

 Examples of metallic acid esters include tetraethoxy titanium, tetra-n-propoxyethane, tetra-isopropoxy titanium, tetrabutoxy titanium, tetrahexoxy titanium, tetrabutoxy zirconium and tetra ethoxy zirconium. Metallic acid esters do not include silicic acid esters, which are described below as examples of an organosilicon compound having no active hydrogen (c).

 The electron donor compounds described above can be used in combination of two or more kinds, or they can be used in combination with the other electron donor compounds (d) described below than said electron donor compounds.

 Of these, alcohols and metallic acid esters are preferred, and alcohols with 6 or more carbon atoms are particularly preferred.

 If the electron-donor compound having 6 or more carbon atoms is used as the electron-donor compound (d-1) in order to make the magnesium compound liquid, its amount is usually not less than 1 mol, preferably from 1 to 40 mol, more preferably from 1.5 to 12 mol, based on 1 mol of magnesium compound. If an electron-donor compound having 5 or fewer carbon atoms is used as an electron-donor compound (d-1), its amount is usually not less than 15 mol, based on 1 mol of the magnesium compound.

 Upon contact of the solid magnesium compound and the electron donor compound (d-1), a hydrocarbon solvent may be used. Examples of hydrocarbon solvents include aliphatic hydrocarbons such as pentane, hexane, heptane, octane, decane, dodecane, tetradecane and kerosene; alicyclic hydrocarbons such as cyclopentane, methylcyclopentane, cyclohexane, methylcyclohexane, cyclooctane and cyclohexene; aromatic hydrocarbons such as benzene, toluene, xylene, ethylbenzene, cumene and zymol; and halogenated hydrocarbons such as carbon tetrachloride, dichloroethane, dichloropropane, trichlorethylene and chlorobenzene.

 When aromatic hydrocarbons are used from these solvents, the alcohol as the electron-donor compound (d-1) is used in the same amount as described above in the case of an electron-donor compound of 6 or more carbon atoms, regardless of the type (number of carbon atoms) of the alcohol used, whereby the magnesium compound can be dissolved. When using aliphatic hydrocarbons and / or alicyclic hydrocarbons, alcohol as an electron-donating compound is used in the above amount according to the number of carbon atoms.

 In the present invention, it is preferred that the solid magnesium compound is contacted with the electron donor compound (d-1) in a hydrocarbon solvent.

In order to dissolve the solid magnesium compound in the electron-donor compound (d-1), the method of contacting the solid magnesium compound with the electron-donor compound (d-1) is usually chosen mainly in the presence of a hydrocarbon solvent and heating it, if necessary. This contacting is carried out at a temperature usually from 0 to 300 ^° C., preferably from 20 to 180 ^° C., more preferably from 50 to 150 ^° C., for about 15 minutes to 5 hours, preferably about 30 minutes to 2 hours.

 (b) Liquid titanium compound.

A tetravalent titanium compound such as a liquid titanium compound is preferably used in the present invention. The tetravalent titanium compound, for example, is a compound represented by the following formula:
Ti (OR) _g X _4-g ,
where R is a hydrocarbon group, X is a halogen atom and 0 ≤ g ≤ 4.

Examples of such compounds include:
titanium tetrahalides such as TiCl ₄ , TiBr ₄ and TiI ₄ ;
alkoxy titanium trigalides such as Ti (OCH ₃ ) Cl ₃ , Ti (OC ₂ H ₅ ) Cl ₃ , Ti (OnC ₄ H ₉ ) Cl ₃ , Ti (OC ₂ H ₅ ) Br ₃ and Ti (OiC ₄ H ₉ ) Br ₃ ;
dialkoxy titanium digalides such as Ti (OCH ₃ ) ₂ Cl ₂ , Ti (OC ₂ H ₂ ) ₂ Cl ₂ , Ti (OnC ₄ H ₉ ) ₂ Cl ₂ and Ti (OC ₂ H ₂ ) ₂ Br ₂ ;
trialkoxy titanium monohalides such as Ti (OCH ₃ ) ₃ Cl, Ti (OC ₂ H ₅ ) ₃ Cl, Ti (OnC ₄ H ₉ ) ₃ Cl, Ti (OC ₂ H ₅ ) ₃ Br; and
tetraalkoxy titanium such as Ti (OCH ₃ ) ₄ , Ti (OC ₂ H ₅ ) ₄ , Ti (OnC ₄ H ₉ ) ₄ , Ti (OiC ₄ H ₉ ) ₄ and Ti (O-2-ethylhexyl) ₄ .

 Of these, titanium tetrahalides are most preferred, and titanium tetrachloride is particularly preferred. These titanium compounds can be used in combination of two or more kinds. Then these compounds can be diluted with the above hydrocarbon solvents, which are used to create the liquid magnesium compound (a).

 (c) Organosilicon compounds having inactive hydrogen.

An organosilicon compound having inactive hydrogen that is used in the invention is represented, for example, by the formula R ¹ _x R ² _y Si (OR ³ ) _z (R ¹ and R ^{2 are} each independently a hydrocarbon group or a halogen, R ³ is a hydrocarbon group, 0 ≤ x <2, 0 ≤ y <2, and 0 <z ≤ 4.

Examples of organosilicon compounds represented by the above formula include:
tetramethoxysilane, tetraethoxysilane, tetrapropoxysilane, tetrabutoxysilane, tetrakis (2-ethylhexyloxy) silane, ethyltrimethoxysilane, ethyltriethoxysilane, vinyltrimethoxysilane, methyltrimethoxysilane, n-propyltriethoxysilane, detsiltrimetoksisilan, cyclopentyltrimethoxysilane, 2-methylcyclopentyltrimethoxysilane, 2,3-dimetiltsiklopentiltrimetoksisilan, cyclohexyltrimethoxysilane, 2-norbornanetrimethoxysilane, 2 norbornanemethyldimethoxysilane, phenyltrimethoxysilane, γ-chloropropyltrimethoxysilane, methyltriethoxysilane, ethyltriethoxysilane, vinyl ietoksisilan, t-butyltriethoxysilane, n-butyltriethoxysilane, izobutiltrietoksisilan, detsiltrietoksisilan, cyclopentyltriethoxysilane, cyclohexyltriethoxysilane, 2-norbornanetriethoxysilane, phenyltriethoxysilane, γ-aminopropyltriethoxysilane, hlorotrietoksisilan, etiltriizopropoksisilan, vinyltributoxysilane, trimethylphenoxysilane, metilalliloksisilan, vinyltris (β-metoksietoksisilan), vinyltriacetoxysilane, dimethyldimethoxysilane, diisopropyldimethoxysilane, tretbutilmetildimetoksisilan , dicyclopentyldimethoxysilane, bis (2-methyl iklopentil) dimethoxysilane, bis (2,3-dimethylcyclopentyl) dimethoxysilane, dicyclohexyldimethoxysilane, cyclohexylmethyldimethoxysilane, diphenyldimethoxysilane, phenylmethyldimethoxysilane, bis-o-tolyldimethoxysilane, bis-m-tolyldimethoxysilane, bis-p-tolyldimethoxysilane, bisethylphenyldimethoxysilane, dimethyldiethoxysilane, tretbutilmetildietoksisilan, tretamilmetildietoksisilan, dicyclopentyldiethoxysilane, diphenyldiethoxysilane, bis-p-tolyldiethoxysilane, cyclohexylmethyldiethoxysilane, trimethylmethoxysilane, trimethylethoxysilane, tricyclo pentylmethoxysilane, tricyclopentylethoxysilane, dicyclopentylmethylmethoxysilane, dicyclopentylethylmethoxysilane, hexenyltrimethoxysilane, cyclopentyldimethylmethoxysilane, cyclopentyl diethylmethoxyethylsilane cyclopentyl diethyl methoxy silane.

 Of these, tetramethoxysilane, tetraethoxysilane and cyclohexylmethyldimethoxysilane are preferably used. In terms of catalytic activity, tetraethoxysilane is particularly preferred.

 In the present invention, it is sufficient that an organosilicon compound having no hydrogen activity (c) is contained in the final solid titanium catalyst component obtained. In the preparation of a solid titanium catalyst component, therefore, an organosilicon compound having an inactive hydrogen (c) cannot itself be used, and compounds capable of producing an organosilicon compound having an inactive hydrogen can be used therein during the process of producing a solid titanium catalytic component.

 (d) Another electron donor compound.

 In preparing the solid titanium catalyst component of the invention, an electron-donor compound having inactive hydrogen (d) may optionally be used in addition to an organosilicon compound having inactive hydrogen (c).

 Examples of such electron-donating compounds (d) include organic acid esters, organic acid halides, organic acid anhydrides, ethers, ketones, tertiary amines, phosphorous esters, phosphoric esters, carboxylic acid amides, nitriles, aliphatic carbonates and pyridines.

More specifically, you can mention:
organic acid esters having from 2 to 18 carbon atoms such as methyl formate, methyl acetate, ethyl acetate, vinyl acetate, propyl acetate, isobutyl acetate, tert-butyl acetate, octyl acetate, cyclohexyl acetate, methyl chloroacetate, ethyl dichloroacetate, ethyl propionate, ethyl trimethyl methyl trimethyl acetate ethyl ethyl crotonate, ethyl cyclohexanecarboxylate, methyl benzoate, ethyl benzoate, propyl benzoate, butyl benzoate, octyl benzoate, cyclohexyl benzoate, phenyl benzoate, benzyl benzoate, toluic methyl ester isloty, toluic acid ethyl ester, amyl ester of toluic acid, ethyl benzoate, methyl anisate, ethyl anisate and ethyl ethoxybenzoate;
acid halides having from 2 to 15 carbon atoms, such as acetyl chloride, benzoyl chloride and toluyl chloride;
acid anhydrides such as acetic anhydride, phthalic anhydride, maleic anhydride, benzoic anhydride, trimellitic anhydride and tetrahydrophthalic anhydride;
ethers having from 2 to 20 carbon atoms, such as methyl ether, ethyl ether, isopropyl ether, butyl ether, amyl ether, tetrahydrofuran, ethylbenzyl ether, ethylene glycol, dibutyl ether, anisole and diphenyl ether;
ketones having from 3 to 20 carbon atoms, such as acetone, methyl ethyl ketone, methyl isobutyl ketone, ethyl n-butyl ketone, acetophenone, benzophenone, benzoquinone and cyclohexanone;
tertiary amines such as trimethylamine, triethylamine, tributylamine, tribenzylamine and tetramethylethylenediamine;
phosphorous esters such as trimethyl phosphite, triethyl phosphite, tri-n-propyl phosphite, triisopropyl phosphite, tri-n-butyl phosphite, triisobutyl phosphite, diethyl n-butyl phosphite and diethyl phenyl phosphite;
esters of phosphoric acid such as trimethyl phosphate, triphenyl phosphate and tritolyl phosphate;
acid amides such as N, N-dimethylacetamide, N, N-diethylbenzamide and N, N-dimethyltoluamide;
nitriles such as acetonitrile, benzonitrile toluonitrile;
aliphatic carbonates such as dimethyl carbonate, diethyl carbonate and ethylene carbonate;
pyridines such as pyridine, methylpyridine, ethylpyridine and dimethylpyridine.

 These compounds may be used in combination of two or more kinds.

 Obtaining a solid titanium catalyst component.

 In the present invention, the solid titanium catalyst component [I] can be obtained from the above ingredients by the following methods.

(1) The liquid magnesium compound (a) and the liquid titanium compound (b) are contacted in the presence of an organosilicon compound having inactive hydrogen (c) (referred to simply as “organosilicon compound (c) hereinafter), in an amount of from 0.25 to 0.35 mol per 1 mol of magnesium compound (a). Then, the temperature of the obtained contact product (i) is brought to a temperature of from 105 to 115 ^o C and maintained at this temperature.

(2) The temperature of the contact product (i) obtained above is adjusted to maintain the contact product (i) at a temperature of 105 to 115 ^° C., and in this step the organosilicon compound (c) is added in an amount of not more than 0.5 mol in based on 1 mol of the magnesium compound (a), wherein the temperature of the contact product (i) is adjusted from a temperature lower by 10 ^° C than the maintained temperature to a temperature at which the temperature increase is completed, or after the temperature increase is completed, thus leading organosilicon contact some compound (c) with the contact product (i).

 Of the above methods, method (2) is preferred in terms of the catalytic activity of the resulting solid titanium catalyst component.

 According to the invention, upon contact of the components, the organosilicon compound (c) is used in a special amount based on the magnesium compound (a).

 Preferably, the titanium compound (b) is used in such a sufficient amount that the solid can precipitate upon contact, even if special precipitating agents are not used. The amount of titanium compound used (b) varies depending on its type, contact conditions, amount of organosilicon compound (s), etc., but it is usually not less than 1 mol, preferably about 5 to 200 moles, more preferably about from 10 to 100 moles, based on 1 mol of the magnesium compound (a). Further, the titanium compound (b) is used in an amount of preferably more than 1 mol, more preferably not less than 5 mol, based on 1 mol of the organosilicon compound (c).

 The above methods are described in more detail below.

 The liquid magnesium compound (a) and / or titanium compound (b) that are in contact with each other may pre-contain the organosilicon compound (c). In this case, the organosilicon compound (c) may optionally be added in the contact step of the magnesium compound (a) and the titanium compound (b). In any case, the total amount of the organosilicon compound (c) based on the magnesium compound (c) is within the above limits.

In the present invention, the contact of the liquid magnesium compound (a) and the liquid titanium compound (b) is carried out at such a low temperature that a solid does not rapidly form upon contact. Characteristically, it is desirable to carry out the contact at a temperature of from -70 to +50 ^° C, preferably from -50 to +30 ^° C, more preferably from -40 to +20 ^° C. The temperatures of all the solutions used for contact may be different from friend. If the contact temperature is too low to precipitate a solid in the contact product (i) at the beginning of contact, then contact at low temperature can be carried out for a long period of time to precipitate a solid.

The temperature of the contact product (i) obtained above is then slowly brought to a temperature of 105 to 115 ^° C. in order to precipitate the solid gradually, further maintaining this temperature.

 The temperature maintenance time is usually in the range from 0.5 to 6 hours, preferably from 1 to 4 hours.

 The time required to reach the temperature varies greatly depending on the size of the reactor, etc.

 When the liquid magnesium compound (a) and the liquid titanium compound (b) are contacted under the above conditions in the presence of an organosilicon compound having inactive hydrogen (c), a granular or spherical solid titanium catalyst component having relatively large particle diameters and excellent particle distribution can be obtained in size. When ethylene is subjected to suspension polymerization using a solid titanium catalyst component with such excellent particle properties, a granular or spherical ethylene polymer having excellent particle size distribution, high bulk density and good flow can be obtained.

According to method (2) in the stage of method (1), where the temperature of the contact product (i) reaches a temperature of from 105 to 115 ^o C and is maintained at this temperature, usually for from 0.5 to 6 hours, preferably from 1 to 4 hours, add the organosilicon compound (c) in an amount of not more than 0.5 mol per 1 mol of the magnesium compound (a), and the temperature of the contact product (i) rises from a temperature lower by 10 ^o C than the maintained temperature to a temperature at where the temperature increase ends, or after (preferably not Slowly after) addition, as the temperature increase is completed, thus realizing the contact of the organosilicon compound (c) with the contact product (i).

 The solid titanium catalyst component of the invention obtained by the above methods includes magnesium, titanium, halogen and an organosilicon compound having inactive hydrogen (c).

In a solid titanium catalyst component, it is desirable that:
the magnesium / titanium ratio (atomic) was in the range of about 2 to 100, preferably about 4 to 50, more preferably 5 to 30;
the halogen / titanium ratio (atomic) was in the range from 4 to 100, preferably from about 5 to 90, more preferably from about 8 to 50;
organosilicon compound / titanium ratio (in moles) was in the range of about 0.01 to 100, preferably about 0.2 to 10, more preferably about 0.4 to 6;
and the organosilicon compound (c) / magnesium ratio (by moles) was in the range of about 0.001 to 0.1, preferably about 0.002 to 0.08, more preferably about 0.005 to 0.05.

 The solid titanium catalyst component may also contain other ingredients than the above, for example, a carrier, and especially other ingredients may be contained in amounts of not more than 50% by weight, preferably not more than 40% by weight, more preferably not more than 30 % by weight, particularly preferably not more than 20% by weight.

 The composition of the solid titanium catalytic component can be determined, for example, by ICP (atomic absorption spectrometry) or by gas chromatography, after which it is sufficient to wash the catalytic component with a large amount of hexane and dry at room temperature and from 0.1 to 1 Torr for at least 2 hours.

The solid titanium catalyst component of the invention is preferably in granular or spherical form, and its specific surface area is preferably not less than 10 m ² / g, preferably about 100 to 1,000 m ² / g.

 In the present invention, the solid titanium catalyst component is typically washed with a hydrocarbon solvent before use.

 Ethylene Polymerization Catalyst.

The ethylene polymerization catalyst according to the invention is formed from:
[I] a solid titanium catalyst component and
[II] an organometallic component.

 The organometallic compound used in the invention preferably means an organometal compound containing a metal selected from Group I or Group II of the Periodic Table.

 Examples of such compounds include an organoaluminum compound, an alkyl complex compound of a metal from Group I and aluminum, and an organometallic compound of a metal from Group II.

An organoaluminum compound means, for example, a compound represented by the following formula:
R ^a _n AlX _3-n ,
where R ^a means a hydrocarbon group from 1 to 12 carbon atoms, X means halogen or hydrogen, and n means from 1 to 3.

R ^a means a hydrocarbon group from 1 to 12 carbon atoms, i.e. an alkyl group, a cycloalkyl group or an aryl group. Particular examples of this include methyl, ethyl, n-propyl, isopropyl, isobutyl, pentyl, hexyl, octyl, cyclopentyl, cyclohexyl, phenyl and tolyl. Examples of such organoaluminum compounds include:
trialkylaluminums such as trimethylaluminum, triethylaluminum, triisopropylaluminum, triisobutylaluminum, trioctylaluminum and tri-2-ethylhexylaluminum;
alkenylaluminiums such as isoprenylaluminum;
dialkyl aluminum halides such as dimethyl aluminum chloride, diethyl aluminum chloride, diisopropyl aluminum chloride, diisobutyl aluminum chloride and dimethyl aluminum bromide;
alkylaluminum sesquichalides such as methylaluminum sesquichloride, ethylaluminum sesquichloride, isopropylaluminum sesquichloride, butylaluminum sesquichloride and ethylaluminum sesquichromide;
aluminum alkyl digalides such as methylaluminum dichloride, ethylaluminum dichloride, isopropylaluminum dichloride and ethylaluminum dibromide; and
alkyl aluminum hydrides such as diethyl aluminum hydride and diisobutyl aluminum hydride.

It is also possible to use, as an organoaluminum compound, a compound represented by the formula:
R ^a _n AlY _3-n ,
where R ^a means the same as above; Y is —OR ^b group, —OSiR ^c ₃ group, —OAlR ^d ₂ group, —NR ^e ₂ group, —SiR ^f ₃ group, or —N (R ^g ) AlR ^h ₂ group; n is from 1 to 2; R ^b , R ^c , R ^d and R ^{h are} each methyl, ethyl, isopropyl, isobutyl, cyclohexyl, phenyl or the like; R ^e means hydrogen, methyl, ethyl, isopropyl, phenyl, trimethylsilyl or the like; and R ^f and R ^{g are} each methyl, ethyl or the like.

Examples of such organoaluminum compounds include:
(i) compounds of the formula R ^a _n Al (OR ^b ) _3-n , for example dimethylaluminum methoxide, diethylaluminum ethoxide and diisobutylaluminum methoxide;
(ii) compounds of the formula R ^a _n Al (OSiR ^c ) _3-n , for example Et ₂ Al (OSiMe ₃ ), (iso-Bu) ₂ Al (OSiMe ₃ ) and (iso-Bu) ₂ Al (OSiEt ₃ );
(iii) compounds of the formula R ^a _n Al (OAlR ^d ₂ ) _3-n , for example Et ₂ AlOAlEt ₂ and (iso-Bu) ₂ AlOAl (iso-Bu) ₂ ;
(iv) compounds of the formula R ^a _n Al (NR ^e ₂ ) _3-n , for example Me ₂ AlNEt ₂ , Et ₂ AlNHMe, Me ₂ AlNHEt, Et ₂ AlN (Me ₃ Si) ₂ and (iso-Bu) ₂ AlN ( Me ₃ Si) ₂ ;
(v) compounds of the formula R ^a _n Al (SiR ^f ₂ ) _3-n , for example (iso-Bu) ₂ AlSiMe ₃ ; and
(vi) compounds of the formula R ^a _n Al [N (R ^g ) -AlR ^h ₂ ] _3-n , for example Et ₂ AlN (Me) -AlEt ₂ and (iso-Bu) ₂ AlN (Et) Al (iso-Bu ) ₂ .

In addition, compounds similar to the above compounds, for example organoaluminum compounds, where two or more aluminum atoms are bonded through an oxygen atom or a nitrogen atom, can also be used. Examples of such compounds include (C ₂ H ₅ ) ₂ AlOAl (C ₂ H ₅ ) ₂ , (C ₄ H ₉ ) ₂ AlOAl (C ₄ H ₉ ) ₂ and (C ₂ H ₅ ) ₂ AlN (C ₂ H ₅ ) Al (C ₂ H ₅ ) ₂ .

 Moreover, aluminoxanes, such as methylaluminoxane, can also be used.

An alkyl complex compound of a Group I metal and aluminum, for example, means a compound represented by the following formula:
M ¹ AlR ^j ₄ ,
where M ¹ means Li, Na or K, and R ^j means a hydrocarbon group from 1 to 15 carbon atoms.

Examples of such compounds include LiAl (C ₂ H ₅ ) ₄ and LiAl (C ₇ H ₁₅ ) ₄ .

The organometallic compound of a Group II metal is represented by the following formula:
R ^k R ¹ M ² ,
where R ^k and R ¹ mean each hydrocarbon group from 1 to 15 carbon atoms or halogen, R ^k and R ¹ may be the same or different except that both of them are halogen, and M ² means Mg, Zn or Cd.

 Examples of such compounds include diethylzinc, diethylmagnesium, butylmagnesium, ethylmagnesium chloride and butylmagnesium chloride.

Of the organoaluminum compounds described above, compounds of the formulas R ^a ₃ AlX _3-n , R ^a _n Al (OR ^b ) _3-n and R ^a _n Al (OAlR ^d ₂ ) _3-n , especially trialkylaluminums, are preferably used.

 The above compounds may be used in combination of two or more kinds.

 Olefins can be prepolymerized on the ethylene polymerization catalyst of the invention.

 The ethylene polymerization catalyst of the invention may further comprise other components for ethylene polymerization in addition to the components described above.

 The method of polymerization of ethylene.

 In the ethylene polymerization method according to the invention, ethylene is polymerized in the presence of an ethylene polymerization catalyst comprising a solid titanium catalyst component [I] and an organometallic compound [II], but ethylene can be copolymerized with a small amount of other olefins.

Examples of olefins include α-olefins of 3 to 20 carbon atoms such as propylene, 1-butene, 1-pentene, 1-hexene, 3-methyl-1-butene, 3-methyl-1-pentene, 3-ethyl-1 -pentene, 4-methyl-1-pentene, 4,4-dimethyl-1-pentene, 4-methyl-1-hexene, 1-octene, 1-decene, 1-dodecene, 1-tetradecene, 1-hexadecene, 1 -octadecene and 1-eicosen. In addition, vinyl compounds, other unsaturated compounds and polyene compounds are also capable of copolymerizing. For example, here may be mentioned:
aromatic vinyl compounds such as styrene, substituted styrenes, allylbenzene, substituted allylbenzenes, vinylnaphthalenes, substituted vinylnaphthalenes, allylnaphthalenes and substituted allylnaphthalenes;
alicyclic vinyl compounds such as vinylcyclopentane, substituted vinylcyclopentanes, vinylcyclohexane, substituted vinylcyclohexanes, vinylcycloheptane, substituted vinylcycloheptanes and allylnorbornane;
cycloolefins such as cyclopentene, cycloheptene, norbornene, 5-methyl-2-norbornene, tetracyclodeodecene and 2-methyl-1,4,5,8-dimethano-1,2,3,4,4a, 5,8,8a octahydronaphthalene; and
unsaturated silane compounds such as allyltrimethylsilane, allyltriethylsilane, 4-trimethylsilyl-1-butene, 6-trimethylsilyl-1-hexene, 8-trimethylsilyl-1-octene and 10-trimethylsilyl-1-decene.

 Two or more kinds of the above copolymerizable monomers can be copolymerized with ethylene.

 In the ethylene polymerization process of the invention, it is desirable that the solid titanium catalyst component [I] is used in an amount of typically about 0.0001 to 1.0 mmol with respect to the titanium atom, based on 1 liter of polymerization volume, and the organometallic compound [II] is used in such an amount that the amount of the metal atom in the compound [II] usually becomes about 1 to 2,000 mol, preferably about 5 to 500 mol, based on 1 mol of the titanium atom in the polymerization system.

 The polymerization can be carried out as liquid phase polymerization, such as solution polymerization or suspension polymerization, or gas phase polymerization.

 When suspension polymerization is used, the polymerization-inactive organic solvent is usually used as the polymerization solvent. Examples of organic solvents include aliphatic hydrocarbons such as propane, butane, pentane, hexane, heptane, octane, decane, dodecane and kerosene; alicyclic hydrocarbons such as cyclopentane, cyclohexane and methylcyclopentane; aromatic hydrocarbons such as benzene, toluene and xylene; and halogenated hydrocarbons such as ethylene chloride and chlorobenzene. These solvents may be used in combination. Together with an organic solvent, the monomer is also capable of copolymerizing, which is also used as a liquid at the reaction temperature.

The polymerization conditions vary depending on the type of polymerization, the type of final ethylene polymer, etc., but the polymerization is usually carried out at a temperature of from about 20 to 300 ^o C, preferably from 50 to 150 ^o C, under pressure from atmospheric to 100 kg / cm ² , preferably about 2 to 50 kg / cm ² .

 If hydrogen is used in the polymerization process, the molecular weight of the final polymer can be modified.

 The polymerization can be carried out periodically, semi-continuously or continuously. In addition, the polymerization can be carried out in two or more stages under various reaction conditions.

 According to the invention, in the polymerization of ethylene, a catalyst is formed using the specific titanium solid catalyst component described above, and therefore an ethylene polymer having excellent particle properties can be obtained with astonishingly high polymerization activities. In the final ethylene polymer, respectively, the amount of catalytic residue per polymer unit, especially the halogen content, is small, and therefore, mold rusting hardly occurs during the molding process. In this case, the obtained ethylene polymer has a low content of finely divided powder and shows excellent particle properties, whereby the polymer can be used without granulation.

The ethylene polymer obtained in the present invention desirably has a specific gravity of from 0.20 to 0.60 g / cm ³ , preferably from 0.25 to 0.60 g / cm ³ .

The ethylene polymer desirably has a melting flow rate (MFR measured according to ASTM D 1238E, 190 ^° C.) of from 0.01 to 5,000 g / 10 min.

 Additives may optionally be added to the ethylene polymer obtained in the invention, such as a heat stabilizer, an anti-degradation stabilizer, an anti-static agent, an anti-stick agent, a lubricant, a nucleating agent, a pigment, a dye, and an inorganic or organic filler.

 EFFECT OF THE INVENTION.

 According to the present invention, a solid titanium catalyst component by which an ethylene polymer having a low finely divided powder content and exhibiting excellent particle properties can be produced in a very high yield per unit catalyst, an ethylene polymerisation catalyst containing a solid titanium catalyst component and a polymerization method ethylene using a catalyst are provided.

 EXAMPLES

 The present invention will now be described in accordance with the following examples, but it should be understood that the invention is not limited to these examples.

 In the following examples, the composition, particle size and volumetric weight of the solid titanium catalyst component were determined by the methods described below.

(1) Magnesium content, titanium content
ICP analysis (ICPF 1000TR, produced by Shimazu Seisakusho K.K.)
(2) Chlorine content
The chlorine content was determined by titration with silver nitrate.

(3) The content of the OR group
The thoroughly dried catalyst was added to an acetone solution containing 10% by weight of water, and the ROH obtained by hydrolysis was quantified by gas chromatography.

(4) Particle size distribution
The particle size distribution was determined by means of a vibrating apparatus (low-tap type, manufactured by Iida Seisakusho K.K.) and sieves (inner diameter 200 mm, available from Bunsei Furui K.K.).

(5) Specific Gravity
The specific gravity was determined in accordance with JIS K 6721.

 Example 1

 Obtaining a solid titanium catalyst component.

4.76 g (50 mmol) of anhydrous magnesium chloride, 28.1 ml of decane and 16.3 g (125 mmol) of 2-ethylhexyl alcohol reacted with each other by heating at 130 ^° C for 3 hours, giving a homogeneous solution. 3.1 g (15 mmol) of tetraethoxysilane was added to the solution and stirred at 50 ^° C. for 2 hours to dissolve tetraethoxysilane.

The entire amount of the homogeneous solution obtained above was cooled at room temperature, and then titanium tetrachloride was added dropwise to 200 ml (1.8 mol) of the titanium tetrachloride at a temperature of 0 ^° C. for 1 hour with stirring. After the dropping was completed, the temperature of the mixture was maintained at 0 ^° C. for 1 hour, then brought to 110 ^° C. for one hour and 45 minutes and maintained at this temperature for 2 hours with stirring.

After the two-hour reaction was completed, the resulting solid was separated by hot filtration. The solid was thoroughly washed with hexane and decane at 110 ^° C. until any titanium compound in the wash liquid was no longer detected to obtain a hexane suspension of the solid titanium catalyst component.

 The composition of the solid titanium catalyst component is shown below in Table 2.

 Polymerization.

500 ml of purified n-heptane were placed in a 1 liter autoclave under nitrogen. Then 0.5 mmol of triethylaluminum and 0.005 mmol (relative to the titanium atom) of the hexane suspension of the solid titanium catalyst component was added and the temperature of the system was brought to 80 ^° C. Hydrogen was supplied to the system so that the pressure became 4.0 kg / cm ² -G and then ethylene was continuously fed for 2 hours so that the total pressure became 8.0 kg / cm ^-1 −G. The polymerization temperature was maintained at 80 ^o C.

 After the polymerization was completed, the obtained ethylene polymer was separated from the n-heptane solvent and dried.

After drying, the polymer powder was obtained in an amount of 184.9 g. This polymer powder had an MFR of 2.8 g / 10 min and an estimated specific gravity of 0.33 g / cm ³ . The results are shown below in Table 3.

 The particle size distribution of the polymer powder is shown below in Table 1.

Example 2. The catalytic component was obtained in the same manner as in Example 1, except that upon receipt of the catalytic component, the reaction time at 110 ^° C. changed by 1.5 hours from 2 hours. Using the catalytic component, the polymerization was carried out in the same manner as in Example 1. The results are shown below in Table 2 and Table 3.

Example 3. The catalytic component was obtained in the same manner as in Example 1, except that upon receipt of the catalytic component, the reaction temperature changed by 105 ^o C from 110 ^o C. Using the catalytic component, the polymerization was carried out in the same manner as in Example 1. The results are shown below in Table 2 and Table 3.

 Example 4. The catalytic component was obtained in the same manner as in Example 1, except that upon receipt of the catalytic component, the amount of decane was changed to 29.3 ml from 28.1 ml and the amount of 2-ethylhexyl alcohol was changed to 15.3 g ( 117.5 mmol) with 16.3 g (125 moles). Using the catalytic component, the polymerization was carried out in the same manner as in Example 1. The results are shown below in Table 2 and Table 3.

 Example 5. The catalytic component was obtained in the same manner as in Example 1 except that upon receipt of the catalytic component, the amount of decane was changed to 37.3 ml from 28.1 ml. Using the catalytic component, the polymerization was carried out in the same manner as in Example 1. The results are shown below in Table 2 and Table 3.

 Comparative example 1.

 Obtaining a solid titanium catalyst component.

4.76 g (50 mmol) of anhydrous magnesium chloride, 29.3 ml of decane and 15.3 g (117.5 mmol) of 2-ethylhexyl alcohol reacted with each other by heating at 130 ^o C for 3 hours to obtain a homogeneous solution . 0.88 g (5.85 mmol) of ethyl benzoate was added to the solution and stirred at 130 ^° C. for 1 hour until the ethyl benzoate was dissolved in the solution.

The entire amount of the homogeneous solution obtained above was cooled to room temperature, and then titanium tetrachloride, maintained at 0 ^° C., was added dropwise in 200 ml (1.8 mol) for one hour with stirring. After the dropping was completed, the temperature of the mixture was brought to 80 ^o C for 1.5 hours. When the temperature of the mixture reached 80 ^{° C.} , 2.34 g (15.6 mmol) of ethyl benzoate was added, and the resulting mixture was maintained at the same temperature for 2 hours with stirring.

After completion of the two-hour reaction, the solid was separated by hot filtration. The solid was resuspended in 20 ml of titanium tetrachloride and then the reaction was continued with heating at 90 ^° C. for 2 hours. After the reaction was completed, the solid was separated again by hot filtration. The solid was thoroughly washed with decane at 110 ^° C. and hexane until any titanium compound in the wash liquid was no longer detected to obtain a hexane suspension of the solid titanium catalyst component. The composition of the solid titanium catalyst component is shown below in Table 2.

 Then, the polymerization was carried out in the same manner as in Example 1, except that the solid titanium catalyst component obtained above was used. The results are shown below in Table 3.

 Comparative Example 2

 Obtaining a solid titanium catalyst component.

7.14 g (75 mmol) of anhydrous magnesium chloride, 37.5 ml of decane and 29.3 g (225 mmol) of 2-ethylhexyl alcohol reacted with each other by heating at 130 ^° C for 2 hours, giving a homogeneous solution. 1.67 g (11.3 mmol) of phthalic anhydride was added to the solution and stirred at 130 ^° C. for 1 hour until the phthalic anhydride was dissolved in the solution.

The entire amount of the obtained homogeneous solution was cooled to room temperature, and then titanium tetrachloride, maintained at -20 ^° C for 1 hour, was added dropwise to 200 ml (1.8 mol). After dropping was completed, the temperature of the mixture was raised to 110 ^° C. for 4 hours and maintained at the same temperature for 2 hours with stirring.

After completion of the two-hour reaction, the solid was separated by hot filtration. The solid was resuspended in 200 ml of titanium tetrachloride and then the reaction was carried out again by heating at 110 ^° C. for 2 hours. After completion of the reaction, the solid was separated again by hot filtration. The solid was thoroughly washed with hexane and decane at 110 ^° C. until any titanium compound in the washing liquid was no longer detected to obtain a hexane suspension of the solid titanium catalyst component. The composition of the solid titanium catalyst component is shown below in Table 2.

 Then polymerization was carried out in the same manner as in Example 1, except that the solid titanium catalyst component obtained above was used. The results are shown in Table 3.

 Comparative example 3.

 Obtaining a solid titanium catalyst component.

2.86 g (30 mmol) of anhydrous magnesium chloride in 150 ml of decane were suspended in a 400 ml four-necked flask. 8.3 g (180 mmol) of ethanol was added to the suspension dropwise over 1 hour with stirring, followed by reaction at room temperature for 1 hour. Then 10.1 g (84 mmol) of diethylaluminum monochloride was added dropwise to the reaction at 30 ^° C. over 1 hour.

Then added 56.9 g (300 mmol) of titanium tetrachloride. The resulting mixture was heated and stirred at 80 ^° C. for 3 hours.

 After completion of the reaction, the resulting solid was separated from the liquid phase. The solid was thoroughly washed with hexane until any titanium compound in the wash liquid was no longer detected to obtain a hexane suspension of the solid titanium catalyst component in this way. The composition of the solid titanium catalyst component is shown below in Table 2.

 Then polymerization was carried out in the same manner as in Example 1, except that the solid titanium catalyst component obtained above was used. The results are shown below in Table 3.

 Comparative example 4.

A solid titanium catalyst component was obtained in the same manner as in Example 1, except that upon receipt of a solid titanium catalyst component, the temperature after contacting a solution of magnesium and titanium tetrachloride (elevated temperature) changed to 90 ^° C. from 110 ^° C.

 The composition of the solid titanium catalyst component is shown below in Table 2. Then, the polymerization was carried out in the same manner as in Example 1, except that the solid titanium catalyst component obtained above was used.

As a result, a powdery ethylene polymer was obtained with a yield of 76.1 g. This powdery ethylene polymer had an MFR of 2.4 g / 10 min and a specific gravity of 0.31 g / cm ³ . The results are presented in Table 3.

 Comparative Example 5

A solid titanium catalytic component was obtained in the same manner as in Example 1, except that the temperature after contacting a solution of magnesium and titanium tetrachloride (elevated temperature) changed to 120 ^o C from 110 ^o C. Using a solid titanium catalytic component, the polymerization was carried out as in the same manner as in Example 1.

 The results are presented below in Table 2 and Table 3.

 Comparative example 6.

 A solid titanium catalyst component was obtained in the same manner as in Example 1, except that upon receipt of the catalyst component, the amount of tetraethoxysilane was changed to 2.1 g (10 mmol) from 3.1 g (15 mmol). Using a solid titanium catalytic component, polymerization was carried out in the same manner as in Example 1.

 The results are presented below in Table 2 and Table 3.

 Comparative Example 7

 A solid titanium catalyst component was obtained in the same manner as in Example 1, except that upon receipt of the catalyst component, the amount of tetraethoxysilane was changed to 4.2 g (20 mmol) from 3.1 g (15 mmol). Using a solid titanium catalytic component, polymerization was carried out in the same manner as in Example 1.

 The results are presented below in Table 2 and Table 3.

 Comparative example 8.

A solid titanium catalyst component was obtained in the same manner as in Example 1, except that upon receipt of the catalyst component, the amount of tetraethoxysilane was changed to 2.1 g (10 mmol) from 3.1 g (15 mmol) and the temperature after contacting the magnesium solution and titanium tetrachloride (elevated temperature) was changed to 90 ^o C from 110 ^o C. Using a solid titanium catalyst component, the polymerization was carried out in the same manner as in Example 1.

 The results are presented below in Table 2 and Table 3.

 Example 6

Obtaining a solid titanium catalyst component
4.76 g (50 mmol) of anhydrous magnesium chloride, 28.1 ml of decane and 16.3 g (125 mmol) of 2-ethylhexyl alcohol were reacted with each other by heating at 130 ^° C for 3 hours to obtain a homogeneous solution. To the solution was added 3.1 g (15 mmol) of tetraethoxysilane and stirred at 50 ^° C. for 2 hours until the tetraethoxysilane was dissolved in the solution.

The entire amount of the homogeneous solution obtained above was cooled to room temperature, and then titanium tetrachloride, maintained at 0 ^° C. for 1 hour with stirring, was added dropwise to 200 ml (1.8 mol). After completion of the dropping, the temperature of the mixture was maintained at 0 ^° C. for 1 hour and 45 minutes. When the temperature of the mixture reached 110 ^° C., 1.0 g (5 mmol) of tetraethoxysilane was added.

The mixture was then stirred at 110 ^° C. for 2 hours. After completion of the 2 hour reaction, the resulting solid was separated by hot filtration. The solid was thoroughly washed with hexane and decane at 110 ^° C. until any titanium compound in the wash liquid was no longer detected to obtain a hexane suspension of the solid titanium catalyst component. The composition of the solid titanium catalyst component is shown below in Table 4.

 Polymerization.

In a 1 liter autoclave was placed 500 ml of purified n-heptane in a nitrogen atmosphere. Then, 0.5 mmol of triethylaluminum and 0.005 mmol (relative to the titanium atom) of the hexane suspension of the solid titanium catalyst component was added and the temperature of the system was brought to 80 ^° C. Hydrogen was supplied to the system so that the pressure became 4.0 kg / cm ² -G and then ethylene was continuously fed for 2 hours so that the total pressure became 8.0 kg / cm ² -G. The polymerization temperature was maintained at 80 ^o C.

 After the polymerization was completed, the obtained ethylene polymer was separated from the n-heptane solvent and dried.

 Example 7

The catalyst component was obtained in the same manner as in Example 6, except that the amount of tetraethoxysilane (second addition) added when the temperature reached 110 ^° C. was changed to 2.1 g (10 mmol) from 1.0 g (5 mmol). Using the catalytic component, the polymerization was carried out in the same manner as in Example 6. The results are shown in Table 4 and Table 5.

 Comparative example 9.

The catalyst component was obtained in the same manner as in Example 6, except that the temperature achieved in the preparation of the catalyst component was changed to 120 ^° C. from 110 ^° C. and the second tetraethoxysilane was added when the temperature reached 120 ^° C. Using the catalyst component , the polymerization was carried out in the same manner as in Example 6. The results are shown in Table 4 and Table 5.

 Comparative Example 10

The catalyst component was obtained in the same manner as in Example 6, except that the temperature achieved in the preparation of the catalyst component was changed to 90 ^° C. from 110 ^° C. and the second tetraethoxysilane addition was carried out when the temperature reached 90 ^° C. Using the catalyst component , the polymerization was carried out in the same manner as in Example 6. The results are shown in Table 4 and Table 5.

Claims (4)

1. A solid titanium catalyst component for ethylene polymerization obtained by a process comprising the step of contacting (a) a liquid magnesium compound with (b) a liquid titanium compound in the presence of (c) an organosilicon compound having inactive hydrogen, and a step of raising the temperature of the obtained contact product (i ) and maintaining the contact product (i) at this temperature, said solid titanium catalyst component comprising magnesium, titanium, halogen and an organosilicon compound having an inactive hydrogen (c), characterized in that the contacting step is carried out at a molar ratio of the organosilicon compound (c) to the magnesium compound (a) equal to 0.25-0.35 mol, based on 1 mol of the magnesium compound (a), and aging the resulting contact product (i) is carried out at 105 - 115 ^o C. 2. A solid titanium catalyst component for ethylene polymerization obtained by a process comprising the step of contacting (a) a liquid magnesium compound with (b) a liquid titanium compound in the presence of (c) an organosilicon compound having inactive hydrogen, and a step of raising the temperature of the obtained contact product (i ) and maintaining it at a given temperature, said solid titanium catalyst component comprising magnesium, titanium, halogen and an organosilicon compound having inactive hydrogen (c), exl. characterized in that the contacting step is carried out at a molar ratio of the organosilicon compound (c) to the magnesium compound (a) equal to 0.25-0.35 mol per 1 mol of the magnesium compound (a), and the contact product obtained is kept (i) carried out at 105 - 115 ^o C with the addition of an organosilicon compound having inactive hydrogen (c) in an amount of not more than 0.5 mol per 1 mol of magnesium compound (a), and the temperature of the contact product (i) rises from a temperature lower by 10 ^o C, than the maintained temperature, before the temperature at which the temperature increase ends, or after the temperature increase ends, contacts compound (c) with the contact product (i).  3. An ethylene polymerization catalyst containing (I) a solid titanium catalyst component and (II) an organoaluminum compound, characterized in that, as a solid titanium catalyst component, the catalyst contains the component according to claim 1 or 2.  4. The method of polymerization of ethylene by polymerization of ethylene in the presence of a catalyst containing a solid titanium catalyst component and an organoaluminum compound, characterized in that the catalyst according to claim 3 is used as a catalyst.

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