Method for producing olefin polymer

Abstract

To provide a suitable method for efficiently producing an olefin polymer containing a relatively large number of polymer components having a high molecular weight such as a molecular weight of 106.5 or more, in which the high molecular weight polymer components preferably contain a relatively large number of structural units derived from an olefin having 3 or more carbon atoms.SOLUTION: There is provided a method for producing an olefin polymer by polymerizing an olefin in the presence of an olefin polymerization catalyst containing a solid titanium catalyst component (A) and an organoaluminum compound (B) having a substituent having a molecular weight of 30 or more. The solid titanium catalyst component (A) is preferably in a form of containing a silicon-containing compound.SELECTED DRAWING: None

Description

[Technical field]

[0001] The present invention relates to a process for producing an olefin polymer containing ethylene. [Background technology]

[0002] Olefin polymers such as ethylene homopolymers and linear low-density ethylene polymers (LLDPE) are excellent in transparency, mechanical strength, etc., and are widely used as raw materials for applications such as packaging materials and containers, such as films and bottles. Various methods have been disclosed for producing such ethylene polymers, and it is known that ethylene polymers can be produced with high polymerization activity by using an olefin polymerization catalyst containing a solid titanium catalyst component containing titanium, magnesium, a halogen, and an electron donor as an optional component (e.g., Patent Document 1). The particle properties of the solid titanium catalyst tend to have a significant effect on the stable operation and efficient production of the production process, and solid titanium catalyst components with excellent particle properties often contain a component such as an electron donor.

[0003] As mentioned above, olefin polymers are suitably used as raw materials for containers as alternative materials to glass, etc. Meanwhile, in recent years, due to growing awareness of environmental issues, there is a demand for further improving the durability of containers using olefin polymers, and there is a demand for olefin polymers that exhibit high performance in environmental stress resistance tests, etc. (e.g., Patent Document 2). In response to this trend, various standards such as PE100 and PE125 have been established. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Publication No. 9-328514 [Patent Document 2] JP 2004-269864 A Summary of the Invention [Problem to be solved by the invention]

[0005] The olefin polymers having excellent durability as described above often contain components with extremely high molecular weights. In addition, appropriate toughness is also required. As such an olefin polymer, an ethylene copolymer containing a high molecular weight component containing a relatively large amount of olefin-derived structural units having 3 or more carbon atoms is considered to be suitable. On the other hand, olefins having 3 or more carbon atoms tend to have a significantly slower polymerization rate than ethylene, although this depends on the type of olefin polymerization catalyst, and the influence of chain transfer reactions is relatively increased, making it relatively difficult to produce such ethylene copolymers.

[0006] Therefore, an object of the present invention is to provide a method for producing an olefin polymer, which uses an olefin polymerization catalyst containing a solid titanium catalyst component, and which can easily produce an ethylene polymer containing a relatively large amount of structural units derived from an olefin having 3 or more carbon atoms, even if the ethylene polymer has a high molecular weight. [Means for solving the problem]

[0007] As a result of investigations conducted by the present inventors to solve the above-mentioned problems, it was found that a method of polymerizing olefins in the presence of an olefin polymerization catalyst containing a solid titanium catalyst containing a specific component and an organoaluminum compound containing a substituent satisfying specific requirements is preferable, and thus the present invention was completed.

[0008] That is, the present invention is specified by the following requirements. [1] (A) containing magnesium, titanium, and a halogen; 10 to 25 mass% magnesium, Titanium: 2 to 12 mass% 1 to 12 mass % of ORa groups (wherein Ra is a hydrocarbon group having 1 to 20 carbon atoms), and (α) 0 to 12 mass% of a compound selected from a silicon-containing compound, an organic acid compound, an organic acid ester compound, a ketone compound, an aldehyde compound, a nitrogen-containing compound, and a phosphorus-containing compound A solid titanium catalyst component comprising: (B) an organoaluminum compound represented by the following formula (1); R3Al···(1) (wherein R is a substituent containing carbon, hydrogen, or a heteroatom, at least one of which has a molecular weight of 30 or more.) A method for producing an olefin polymer, which comprises polymerizing an olefin in the presence of an olefin polymerization catalyst comprising the following compound: (PE1) the content of structural units derived from ethylene is 90 mol % or more and 99.8 mol % or less; (PE2) the content of structural units derived from olefins having 3 to 20 carbon atoms is 0.2 mol % or more and 10 mol % or less (provided that the total of the structural units derived from ethylene and the structural units derived from olefins having 3 to 20 carbon atoms is 100 mol %); (D) Density is 900-960 kg / m 3 ; (H) Molecular weight determined by GPC measurement is 10 6.5 The content of the above components is 1.5 mass % or more.

[0009] [2] The method for producing an olefin polymer according to [1], wherein at least one of R in the formula (1) has a molecular weight of 35 or more and 300 or less.

[0010] [3] The method for producing an olefin polymer according to [1] or [2], wherein at least one of R in the formula (1) is a hydrocarbon group consisting of carbon atoms and hydrogen atoms.

[0011] [4] 2. The method for producing an olefin polymer according to claim 1, wherein the (A) solid titanium catalyst component is a solid titanium catalyst component obtained by contacting (a) a liquid magnesium compound with (b) a liquid titanium compound in the presence of (c) an organosilicon compound having no active hydrogen in an amount of 0.25 to 0.35 mol per 1 mol of the magnesium compound (a), and heating the resulting contact product (i) to a temperature within the range of 105 to 115°C and maintaining the temperature. Effect of the Invention

[0012] Using the above method, the molecular weight of 6.5 It is easy to produce a polymer containing a high molecular weight component exceeding 1000 nm, and there is a tendency to easily obtain a polymer having a relatively large number of branched structures that are considered to be derived from olefins having 3 or more carbon atoms in the high molecular weight component. Preferably, the branched structure content also tends to be less dependent on the molecular weight. For this reason, it becomes possible to industrially produce an olefin polymer having an appropriate branched structure in a wide molecular weight range. [Brief description of the drawings]

[0013] [Figure 1] FIG. 1 shows GPC-IR measurement charts of Example 1 and Comparative Example 1. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0014] The solid titanium catalyst component, the ethylene polymerization catalyst containing the same, and the ethylene polymerization method according to the present invention will be described below. In the present invention, the term "polymerization" may be used in a sense including not only homopolymerization but also copolymerization, and the term "polymer" may be used in a sense including not only homopolymer but also copolymer.

[0015] <(A) Solid titanium catalyst component> The solid titanium catalyst component (A) of the present invention is Contains magnesium, titanium, and halogens; 10 to 25 mass% magnesium, Titanium: 2 to 12 mass% 1 to 12 mass % of ORa groups (where Ra is a hydrocarbon group having 1 to 20 carbon atoms), and (α) 0 to 12 mass% of a compound selected from a silicon-containing compound, an organic acid compound, an organic acid ester compound, a ketone compound, an aldehyde compound, a nitrogen-containing compound, and a phosphorus-containing compound Contains:

[0016] Such a solid titanium catalyst component can be selected from known solid titanium catalyst components, such as those disclosed in Patent Document 1 and WO 2009 / 125729, which contain an alicyclic dicarboxylate.

[0017] The lower limit of the magnesium content is preferably 11 mass%, more preferably 12 mass%, and even more preferably 13 mass%, while the upper limit is preferably 23 mass%, more preferably 22 mass%, and even more preferably 21 mass%. The lower limit of the titanium content is preferably 3 mass%, more preferably 5 mass%, while the upper limit is preferably 11 mass%, more preferably 10 mass%, and even more preferably 9 mass%. The lower limit of the ORa group is preferably 1.2% by mass, more preferably 2% by mass, while the upper limit is preferably 11% by mass, more preferably 10% by mass, and even more preferably 9% by mass. Within the above range, olefins including ethylene can be polymerized with high activity to obtain high molecular weight olefin polymers, and the titanium catalyst component is suitable as a solid titanium catalyst component having excellent particle properties.

[0018] The Ra is a substituent having 1 to 20 carbon atoms. It is preferably a hydrocarbon group consisting of carbon and hydrogen. A preferred example of such a Ra substituent is, for example, a structure corresponding to an alcohol used in combination with a magnesium compound described later. Among them, preferred specific examples include aliphatic hydrocarbons such as methyl group, ethyl group, propyl group, butyl group, hexyl group, octyl group, 2-ethylhexyl group, decyl group, undecyl group, tetradecyl group, hexadecyl group, octadecyl group, and eicosyl group; alicyclic hydrocarbon groups such as cyclopentyl group, cyclohexyl group, and cyclohexylmethyl group; and aromatic substituents such as phenyl group, tolyl group, and benzyl group. Among them, aliphatic hydrocarbon groups are preferred, more preferably hydrocarbon groups having 1 to 10 carbon atoms, and even more preferably ethyl group, butyl group, hexyl group, 2-ethylhexyl group, octyl group, and decyl group. In particular, an embodiment containing an ethyl group is preferred, and an embodiment in which a substituent having 5 or less carbon atoms is combined with a substituent having 6 to 10 carbon atoms, such as a combination of an ethyl group and a 2-ethylhexyl group, is preferred.

[0019] The above alkoxy group having 5 or less carbon atoms (ORa L The content of ) is preferably 0.5 to 5 mass %. Such a substituent may be introduced into the solid titanium catalyst component, for example, from the alcohol compound used in the preparation of the liquid magnesium compound described below.

[0020] (α) Silicon-containing compounds and other compounds The solid titanium catalyst component used in the present invention is characterized by containing 0 to 12 mass% of a compound selected from silicon-containing compounds, organic acid compounds, organic acid ester compounds, ketone compounds, aldehyde compounds, nitrogen-containing compounds, and phosphorus-containing compounds. The preferable lower limit is 0.2 mass%, and the preferable upper limit is 10 mass%, more preferably 9 mass%, and even more preferably 8 mass%. Examples of such compounds include (c) organic silicon compounds not having active hydrogen, which will be introduced as examples of the solid titanium catalyst component described later, and (d) components derived from other electron donors.

[0021] Among the solid titanium catalyst components that satisfy the above requirements, the solid titanium catalyst component disclosed in the above-mentioned Patent Document 1 is preferred in the present invention. Preferred examples thereof are introduced below.

[0022] The solid titanium catalyst component (A) according to the present invention is obtained by contacting (a) a liquid magnesium compound, (b) a liquid titanium compound, and a specific amount of (c) an organosilicon compound having no active hydrogen per 1 mole of the magnesium compound (a) in a manner described below, and contains magnesium, titanium, a halogen, and (c) an organosilicon compound having no active hydrogen. First, each component used in preparing the solid titanium catalyst component (A) in the present invention will be described below.

[0023] (a) Liquid magnesium compound In the present invention, when preparing the solid titanium catalyst component, the magnesium compound is used in a liquid state, and when the magnesium compound is in a solid state, it is liquefied before use. As the magnesium compound, a magnesium compound (a-1) having reducing ability and a magnesium compound (a-2) having no reducing ability can be used.

[0024] (a-1) As an example of the magnesium compound having reducing ability, there can be mentioned an organomagnesium compound represented by the following formula: X n MgR 2-n (In the formula, n is 0≦n<2, R is a hydrogen atom or an alkyl group, an aryl group or a cycloalkyl group having 1 to 20 carbon atoms, and when n is 0, the two R's may be the same or different. X is a halogen.)

[0025] Specific examples of such organic magnesium compounds having reducing ability include dialkyl magnesium compounds such as dimethyl magnesium, diethyl magnesium, dipropyl magnesium, dibutyl magnesium, diamyl magnesium, dihexyl magnesium, didecyl magnesium, octylbutyl magnesium, and ethylbutyl 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 butyl ethoxy magnesium, ethyl butoxy magnesium, and octyl butoxy magnesium; and butyl magnesium hydride.

[0026] (a-2) Specific examples of magnesium compounds that do not have reducing ability 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; allyloxymagnesium halides such as phenoxymagnesium chloride and methylphenoxymagnesium chloride; alkoxymagnesium such as ethoxymagnesium, isopropoxymagnesium, butoxymagnesium, n-octoxymagnesium, and 2-ethylhexoxymagnesium; allyloxymagnesium such as phenoxymagnesium and dimethylphenoxymagnesium; magnesium carboxylates such as magnesium laurate and magnesium stearate; magnesium metal; and magnesium hydride.

[0027] These magnesium compounds (a-2) without reducing ability may be compounds derived from the magnesium compounds (a-1) with reducing ability described above, or compounds derived during the preparation of the catalyst component. To derive the magnesium compounds (a-2) without reducing ability from the magnesium compounds (a-1) with reducing ability, for example, the magnesium compounds (a-1) with reducing ability may be contacted with alcohols, ketones, esters, ethers, siloxane compounds, halogen-containing silane compounds, halogen-containing aluminum compounds, acid halides, or other halogen-containing compounds, or compounds having OH groups or active carbon-oxygen bonds.

[0028] Furthermore, in the present invention, a compound (a-2) having no reducing ability can be derived from a magnesium compound (a-1) having reducing ability by using an organosilicon compound (c) having no active hydrogen, as described below. Two or more magnesium compounds can also be used in combination.

[0029] The magnesium compounds as described above may form complex compounds or composite compounds with metal compounds other than magnesium, such as aluminum, zinc, boron, beryllium, sodium, and potassium, for example, organoaluminum compounds described below, or may be used in combination with these other metal compounds.

[0030] In preparing the solid titanium catalyst component (A), magnesium compounds other than those mentioned above can be used, but it is preferable that the magnesium compound is present in the form of a halogen-containing magnesium compound in the finally obtained solid titanium catalyst component (A). Therefore, when a magnesium compound not containing a halogen is used, it is preferable to contact the magnesium compound with a halogen-containing compound during the preparation of the catalyst component.

[0031] Among the above compounds, magnesium compounds having no reducing ability are preferred, and halogen-containing magnesium compounds are particularly preferred, and among these, magnesium chloride, alkoxy magnesium chloride, and aryloxy magnesium chloride are preferably used.

[0032] In the present invention, when the magnesium compound is solid, it can be liquefied by using an electron donor (d-1). As the electron donor (d-1), alcohols, carboxylic acids, aldehydes, amines, metal acid esters, etc. can be used. Specific examples of the alcohols include aliphatic alcohols such as methanol, ethanol, propanol, isopropyl alcohol, butanol, pentanol, hexanol, 2-methylpentanol, 2-ethylbutanol, heptanol, 2-ethylhexanol, octanol, decanol, dodecanol, tetradecyl alcohol, octadecyl alcohol, undecenol, oleyl 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, nonylphenol, and naphthol; alkoxy group-containing alcohols such as n-butyl cellosolve, ethyl cellosolve, 1-butoxy-2-propanol, and methylcarbitol; and halogen-containing alcohols such as trichloromethanol, trichloroethanol, and trichlorohexanol.

[0033] The carboxylic acids are preferably those having 7 or more carbon atoms, such as caprylic acid, 2-ethylhexanoic acid, nonylic acid, undecylenic acid, etc. The acetaldehydes are preferably those having 7 or more carbon atoms, such as caprylaldehyde, 2-ethylhexylaldehyde, undecylaldehyde, benzaldehyde, tolualdehyde, naphthaldehyde, etc. The amines are preferably those having 6 or more carbon atoms, such as heptylamine, octylamine, 2-ethylhexylamine, nonylamine, decylamine, undecylamine, laurylamine, etc.

[0034] Examples of metal acid esters include tetraethoxytitanium, tetra-n-propoxytitanium, tetra-i-propoxytitanium, tetrabutoxytitanium, tetrahexoxytitanium, tetrabutoxyzirconium, and tetraethoxyzirconium. The metal acid esters do not include silicate esters as described below as (c) organic silicon compounds having no active hydrogen. These can be used in combination of two or more kinds, and can also be used in combination with an electron donor (d) other than the above as described below. Among these, alcohols and metal acid esters are preferred, and alcohols having 6 or more carbon atoms are particularly preferred.

[0035] When the electron donor (d-1) is used to liquefy a magnesium compound, it is usually used in an amount of about 1 mole or more, preferably 1 to 40 moles, and more preferably 1.5 to 12 moles, per mole of the magnesium compound when an electron donor having 6 or more carbon atoms is used as the electron donor (d-1). When an electron donor having 5 or less carbon atoms is used, it is usually necessary to use about 15 moles or more per mole of the magnesium compound.

[0036] A hydrocarbon solvent can be used when the solid magnesium compound is brought into contact with the electron donor (d-1). Examples of such a hydrocarbon solvent 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 cymene, and halogenated hydrocarbons such as carbon tetrachloride, dichloroethane, dichloropropane, trichloroethylene, and chlorobenzene.

[0037] When aromatic hydrocarbons are used among these solvents, the electron donor (d-1), for example, alcohols, can dissolve the magnesium compound when used in the amount shown above for the electron donor having 6 or more carbon atoms, regardless of its type (number of carbon atoms). When aliphatic hydrocarbons and / or alicyclic hydrocarbons are used, the alcohols as the electron donor (d-1) are used in an amount according to the number of carbon atoms as described above.

[0038] In the present invention, it is preferable to contact the solid magnesium compound with the electron donor (d-1) in a hydrocarbon solvent. To dissolve the solid magnesium compound in the electron donor (d-1), the solid magnesium compound is generally contacted with the electron donor (d-1) preferably in the presence of a hydrocarbon solvent, and heated as necessary. This contact is usually performed at a temperature of 0 to 300°C, preferably 20 to 180°C, more preferably 50 to 150°C, for about 15 minutes to 20 hours, preferably about 30 minutes to 10 hours.

[0039] (b) Liquid titanium compound In the present invention, a tetravalent titanium compound is preferably used as the liquid titanium compound. Examples of such a tetravalent titanium compound include the compound represented by the following formula: Ti(OR) g X 4-g (In the formula, R is a hydrocarbon group, X is a halogen atom, and 0≦g≦4.)

[0040] Examples of such compounds include titanium tetrahalides such as TiCl4, TiBr4, and TiI4; trihalogenated alkoxytitaniums such as Ti(OCH3)Cl3, Ti(OC2H5)Cl3, Ti(On-C4H9)Cl3, Ti(OC2H5)Br3, and Ti(O-iso-C4H9)Br3; dihalogenated dialkoxytitaniums such as Ti(OCH3)2Cl2, Ti(OC2H5)2Cl2, Ti(On-C4H9)2Cl2, and Ti(OC2H5)2Br2; monohalogenated trialkoxytitaniums such as Ti(OCH3)3Cl, Ti(OC2H5)3Cl, Ti(On-C4H9)3Cl, and Ti(OC2H5)3Br; and tetraalkoxytitaniums such as Ti(OCH3)4, Ti(OC2H5)4, Ti(On-C4H9)4, Ti(O-iso-C4H9)4, and Ti(O-2-ethylhexyl)4. Among these, titanium tetrahalides are preferred, and titanium tetrachloride is particularly preferred. These titanium compounds can also be used in combinations of two or more. Further, they may be diluted with a hydrocarbon solvent as shown when liquefying the (a) magnesium compound and then used.

[0041] (c) Organosilicon compound having no active hydrogen The organosilicon compound having no active hydrogen used in the present invention is, for example, R 1 x R 2 y Si(OR 3 ) z (R 1 , R 2 are each independently a hydrocarbon group or a halogen, and R 3 is a hydrocarbon group, where 0 ≦ x < 2, 0 ≦ y < 2, and 0 < z ≦ 4.)

[0042] Specific examples of the organosilicon compounds represented by such a formula include tetramethoxysilane, tetraethoxysilane, tetrapropoxysilane, tetrabutoxysilane, tetrakis(2-ethylhexyloxy)silane, ethyltrimethoxysilane, ethyltriethoxysilane, vinyltrimethoxysilane, methyltrimethoxysilane, n-propyltriethoxysilane, decyltrimethoxysilane, cyclopentyltrimethoxysilane, 2-methylcyclopentyltrimethoxysilane, 2,3-dimethylcyclopentyltrimethoxysilane, cyclohexyltrimethoxysilane, 2-norbornanetrimethoxysilane, 2-norbornanemethyldimethoxysilane, phenyltrimethoxysilane, γ-chloropropyltrimethoxysilane, methyltriethoxysilane, ethyltriethoxysilane, vinyl ... Ethoxysilane, t-butyltriethoxysilane, n-butyltriethoxysilane, iso-butyltriethoxysilane, decyltriethoxysilane, cyclopentyltriethoxysilane, cyclohexyltriethoxysilane, 2-norbornanetriethoxysilane, phenyltriethoxysilane, gamma-aminopropyltriethoxysilane, chlorotriethoxysilane, ethyltriisopropoxysilane, vinyltributoxysilane, trimethylphenoxysilane, methyltriallyloxy(allyoxy)silane, vinyltris(β-methoxyethoxysilane), vinyltriacetoxysilane, dimethyldimethoxysilane, diisopropyldimethoxysilane, t-butylmethyldimethoxysilane, dicyclopentyldimethoxysilane, bis(2-methylcyclopentyl)dimethoxysilane, bis(2,3-Dimethylcyclopentyl)dimethoxysilane, dicyclohexyldimethoxysilane, cyclohexylmethyldimethoxysilane, diphenyldimethoxysilane, phenylmethyldimethoxysilane, bis-o-tolyldimethoxysilane, bis-m-tolyldimethoxysilane, bis-p-tolyldimethoxysilane, bis-ethylphenyldimethoxysilane, dimethyldiethoxysilane, t-butylmethyldiethoxysilane, t-amylmethyldiethoxysilane, dicyclopentyldiethoxysilane, diphenyldiethoxysilane, bis-p-tolyldi Examples of the silane include ethoxysilane, cyclohexylmethyldiethoxysilane, trimethylmethoxysilane, trimethylethoxysilane, tricyclopentylmethoxysilane, tricyclopentylethoxysilane, dicyclopentylmethylmethoxysilane, dicyclopentylethylmethoxysilane, hexenyltrimethoxysilane, cyclopentyldimethylmethoxysilane, cyclopentyldiethylmethoxysilane, dicyclopentylmethylethoxysilane, cyclopentyldimethylethoxysilane, and dimethyltetraethoxydisiloxane.

[0043] Of these, tetramethoxysilane, tetraethoxysilane, cyclohexylmethyldimethoxysilane, etc. are preferably used, with tetraethoxysilane being particularly preferred from the standpoint of catalytic activity.

[0044] In the above-mentioned embodiment, it is sufficient that the organosilicon compound (c) having no active hydrogen is contained in the finally obtained solid titanium catalyst component. Therefore, when preparing the solid titanium catalyst component, it is not necessary to use the organosilicon compound (c) having no active hydrogen as described above. In the process of preparing the solid titanium catalyst component, other compounds that can generate an organosilicon compound having no active hydrogen can also be used.

[0045] (d) Other electron donors In the present invention, when preparing the solid titanium catalyst component, it is preferable to use the above-mentioned organosilicon compound (c) having no active hydrogen, but other electron donors (d) having no active hydrogen can also be used.

[0046] In the present invention, such other electron donors (d) include, for example, organic acid esters, organic acid halides, organic acid anhydrides, ethers, ketones, tertiary amines, phosphites, phosphates, carboxylic acid amides, nitriles, aliphatic carbonates, pyridines, etc. More specifically, methyl formate, methyl acetate, ethyl acetate, vinyl acetate, propyl acetate, i-butyl acetate, t-butyl acetate, octyl acetate, cyclohexyl acetate, methyl chloroacetate, ethyl dichloroacetate, ethyl propionate, ethyl pyruvate, ethyl pivalate, methyl butyrate, ethyl valerate, methyl methacrylate, ethyl crotonate, ethyl cyclohexanecarboxylate, methyl benzoate, ethyl benzoate, propyl benzoate, butyl benzoate, octyl benzoate, cyclohexyl benzoate, etc. organic acid esters having 2 to 18 carbon atoms, such as xyl, phenyl benzoate, benzyl benzoate, methyl toluate, ethyl toluate, amyl toluate, ethyl ethylbenzoate, methyl anisate, ethyl anisate, and ethyl ethoxybenzoate; acid halides having 2 to 15 carbon atoms, such as acetyl chloride, benzoyl chloride, and toluic acid chloride; acid anhydrides, such as acetic anhydride, phthalic anhydride, maleic anhydride, benzoic anhydride, trimellitic anhydride, and tetrahydrophthalic anhydride; methyl ethers; Ethers with 2 to 20 carbon atoms, such as ethyl ether, isopropyl ether, butyl ether, amyl ether, tetrahydrofuran, ethyl benzyl ether, ethylene glycol dibutyl ether, anisole, and diphenyl ether; ketones with 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; phosphites, such as trimethyl phosphite, triethyl phosphite, tri-n-propyl phosphite, triisopropyl phosphite, tri-n-butyl phosphite, triisobutyl phosphite, diethyl n-butyl phosphite, and diethylphenyl phosphite; phosphates, such as trimethyl phosphate, triphenyl phosphate, and tritolyl phosphate; N,N-dimethylamide acetate, N,Examples of the compound include acid amides such as N-diethylamide and toluic acid N,N-dimethylamide, nitriles such as acetonitrile, benzonitrile, and tolunitrile, aliphatic carbonates such as dimethyl carbonate, diethyl carbonate, and ethylene carbonate, and pyridines such as pyridine, methylpyridine, ethylpyridine, and dimethylpyridine. Two or more of these compounds can also be used in combination.

[0047] (Preparation of solid titanium catalyst component (A)) The following is a specific method for preparing the solid titanium catalyst component (A) using the above-mentioned components in the present invention. (1) (a) a liquid magnesium compound is contacted with (b) a liquid titanium compound in the presence of (c) an organosilicon compound having no active hydrogen (hereinafter simply referred to as organosilicon compound (c)) in an amount of 0.25 to 0.35 mol per mol of the magnesium compound (a), and the resulting contact product (i) is heated to a temperature within the range of 105 to 115°C and maintained at this temperature. (2) In the process of heating the contact product (i) and maintaining it at a temperature within the range of 105 to 115°C as described above, an organosilicon compound (c) is added in an amount of 0.5 mol or less per mol of the magnesium compound (a) and contacted with the contact product (i) during the period from a temperature 10°C lower than the maintaining temperature to the end of the temperature rise or after the end of the temperature rise. In the present invention, among the above methods, the method (2) may be preferable in terms of the catalytic activity of the resulting solid titanium catalyst component.

[0048] In the present invention, when each component is contacted, the organosilicon compound (c) is used in the amount specified above relative to the magnesium compound (a). The titanium compound (b) is preferably used in a sufficient amount to precipitate a solid product by contact without adding a special precipitation means. The amount of titanium compound (b) used varies depending on the type, contact conditions, amount of organosilicon compound (c) used, etc., but is usually preferably about 1 mole or more relative to 1 mole of magnesium compound (a), more preferably about 5 to about 200 moles, particularly preferably about 10 to about 100 moles. The titanium compound (b) is preferably used in an amount exceeding 1 mole relative to 1 mole of organosilicon compound (c), more preferably 5 moles or more.

[0049] Each of the above contact methods will be explained in more detail. The liquid magnesium compound (a) and / or titanium compound (b) used for contacting the liquid magnesium compound (a) with the titanium compound (b) may contain an organosilicon compound (c) in advance. In this case, it is not necessary to add the organosilicon compound (c) when the magnesium compound (a) and the titanium compound (b) are contacted, but it may be added. In either case, the total amount of the organosilicon compound (c) relative to the magnesium compound (a) should be within the above range.

[0050] In the present invention, the liquid magnesium compound (a) is preferably contacted with the liquid titanium compound (b) in the presence of the organosilicon compound (c) at a low temperature such that a solid is not rapidly formed by the contact, specifically, at a temperature of -70 to +50°C, preferably -50 to +30°C, and more preferably -40 to +20°C. The temperatures of the solutions used in the contact may be different. When the contact temperature is too low at the beginning of the contact and a solid is not precipitated in the contact product (i), the contact can be continued for a long time at a low temperature to precipitate a solid.

[0051] In the present invention, the contact product (i) obtained above is then gradually heated to a temperature within the range of 105 to 115°C to gradually precipitate a solid material, and this temperature is maintained. The holding time is usually about 0.5 to 6 hours, preferably about 1 to 4 hours. The time required for heating varies greatly depending on the scale of the reactor, etc.

[0052] Under such conditions, when the liquid magnesium compound (a) is contacted with the liquid titanium compound (b) in the presence of the organosilicon compound (c) having no active hydrogen, a granular or spherical solid titanium catalyst component having a relatively large particle size and a good particle size distribution can be obtained. When ethylene is slurry polymerized using such a solid titanium catalyst component having excellent particle properties, an ethylene polymer having a granular or spherical shape, an excellent particle size distribution, a high bulk density and good flowability can be obtained.

[0053] In the contact method (2), in the above-mentioned (1), the contact product (i) is heated to a temperature within the range of 105 to 115°C and maintained at this temperature for usually 0.5 to 6 hours, preferably 1 to 4 hours. During this process, an organosilicon compound (c) is added in an amount of 0.5 mol or less per mol of the magnesium compound (a) and contacted with the contact product (i) during the period from a temperature 10°C lower than the maintained temperature to the end of the temperature increase or after the end of the temperature increase (preferably immediately after).

[0054] The solid titanium catalyst component according to the present invention prepared as described above contains magnesium, titanium, halogen, and (c) an organosilicon compound having no active hydrogen. In this solid titanium catalyst component, the magnesium / titanium (atomic ratio) is 0.5 to 50, preferably 1 to 40, more preferably 2 to about 30, the halogen / titanium (atomic ratio) is 4 to 50, preferably 5 to 40, more preferably 6 to 30, and the organosilicon compound (c) / titanium (molar ratio) is 0.01 to 50, preferably 0.02 to 10, more preferably 0.03 to 6. The organosilicon compound (c) / magnesium (molar ratio) is preferably about 0.001 to 1, preferably about 0.002 to about 0.5, particularly preferably 0.005 to 0.1.

[0055] The solid titanium catalyst component may contain other components such as a carrier in addition to the above components, and specifically may contain other components in an amount of 50 mass % or less, preferably 40 mass % or less, more preferably 30 mass % or less, and further preferably 20 mass % or less. The composition of the catalyst component can be measured by ICP (atomic absorption spectrometry), gas chromatography, etc., after thoroughly washing the solid titanium catalyst component with a large amount of hexane and drying it under conditions of 0.1 to 1 Torr and room temperature for 2 hours or more.

[0056] The shape of the solid titanium catalyst component according to the present invention is preferably granular or nearly spherical, and its specific surface area is about 10 m 2 / g or more, preferably about 100 to 1000m 2 In the present invention, the solid titanium catalyst component is usually used after washing with a hydrocarbon solvent.

[0057] (Olefin polymerization catalyst) The olefin polymerization catalyst according to the present invention is formed from the above-mentioned (A) solid titanium catalyst component and (B) an organoaluminum compound. The organoaluminum compound used in the present invention is specified by the following formula (1). R3Al···(1) (The above R is a substituent selected from the group including a hydrocarbon group having 1 to 20 carbon atoms, such as an alkyl group, a cycloalkyl group, or an aryl group, as well as a halogen atom.)

[0058] In the present invention, the halogen atom includes an embodiment as a substituent that can be expressed, for example, in the case of a chlorine atom, as "Cl-" (the "-" is a symbol representing a covalent bond).

[0059] In the present invention, at least one of R is a substituent having a molecular weight (in the case of a halogen atom, this corresponds to the atomic weight) of 30 or more. The lower limit of the molecular weight is preferably 32, more preferably 35, and particularly preferably 37. There is no particular restriction on the upper limit of the molecular weight, but it is preferably 300, more preferably 250, even more preferably 200, particularly preferably 150, and especially preferably 100. Preferably, all R are substituents having a molecular weight of 30 or more.

[0060] Specific examples of the substituent include an n-propyl group, an isopropyl group, an isobutyl group, a pentyl group, a hexyl group, an octyl group, a cyclopentyl group, a cyclohexyl group, a phenyl group, a tolyl group, a fluorine atom, a chlorine atom, a bromine atom, an iodine atom, etc., and essential substituents include an n-propyl group, an isopropyl group, an isobutyl group, a pentyl group, a hexyl group, an octyl group, a cyclopentyl group, a cyclohexyl group, a phenyl group, a tolyl group, a chlorine atom, a bromine atom, an iodine atom, etc. In addition to the above-mentioned substituents, a methyl group and an ethyl group may be included.

[0061] Specific examples of essential organoaluminum compounds among these organoaluminum compounds include trialkylaluminums such as triisopropylaluminum, triisobutylaluminum, trioctylaluminum, and tri-2-ethylhexylaluminum, alkenylaluminums such as isoprenylaluminum, dialkylaluminum halides such as dimethylaluminum chloride, diethylaluminum chloride, diisopropylaluminum chloride, and diisobutylaluminum chloride, and dimethylaluminum bromide, alkylaluminum sesquihalides such as methylaluminum sesquichloride, ethylaluminum sesquichloride, isopropylaluminum sesquichloride, butylaluminum sesquichloride, and ethylaluminum sesquibromide, alkylaluminum dihalides such as methylaluminum dichloride, ethylaluminum dichloride, isopropylaluminum dichloride, and ethylaluminum dibromide, and alkylaluminum hydrides such as diisobutylaluminum hydride. The above organoaluminum compounds can also be used in combination with organoaluminum compounds containing only substituents with a molecular weight of less than 30, such as trimethylaluminum, triethylaluminum, and diethylaluminum hydride.

[0062] The above-mentioned organoaluminum compounds are preferred in the present invention. Among them, organoaluminum compounds having relatively small substituents such as triisopropylaluminum, triisobutylaluminum, trioctylaluminum, diethylaluminum chloride, and ethylaluminum sesquichloride are preferred.

[0063] Further, examples of the organoaluminum compound include compounds represented by the following formula: R a n AlY 3-n In the above formula, R a is the same as above, and Y is -OR b Group, -OSiR c 3 groups, -OAlR d2 units, -NR e 2 units, -SiR f 3 groups or -N(R g )AlR h 2 groups, n is 1 to 2, and R b , R c , R d and R h is a methyl group, an ethyl group, an isopropyl group, an isobutyl group, a cyclohexyl group, a phenyl group, etc., and R e is hydrogen, methyl, ethyl, isopropyl, phenyl, trimethylsilyl, etc., and R f and R g is a methyl group, an ethyl group, etc.

[0064] As such an organoaluminum compound, specifically, the following compounds are used: (i)R a n Al(OR b ) 3-n Dimethylaluminum methoxide, diethylaluminum ethoxide, diisobutylaluminum methoxide, etc. (ii)R a n Al(OSiR c 3) 3-n Et2Al(OSiMe3), (iso-Bu)2Al(OSiMe3), (iso-Bu)2Al(OSiEt3), etc. (iii)R a n Al(OAlR d 2) 3-n Et2AlOAlEt2, (iso-Bu)2AlOAl(iso-Bu)2, etc. (iv) R a n Al(NR e 2) 3-n Me2AlNEt2, Et2AlNHMe, Me2AlNHEt, Et2AlN(Me3Si)2, (iso-Bu)2AlN(Me3Si)2, etc. (v)R an Al(SiR f 3) 3-n (iso-Bu)2AlSiMe3, etc. (vi)R a n Al〔N(R g )-AlR h 2) 3-n Et2AlN(Me)-AlEt2, (iso-Bu)2AlN(Et)-Al(iso-Bu)2, etc.

[0065] In addition, there may be mentioned similar compounds such as organoaluminum compounds in which two or more aluminum atoms are bonded via oxygen or nitrogen atoms, more specifically, (C2H5)2AlOAl(C2H5)2, (C4H9)2AlOAl(C4H9)2, (C2H5)2AlN(C2H5)Al(C2H5)2, etc., and further aluminoxanes such as methylaluminoxane.

[0066] Examples of the alkyl complexes of Group I metals and aluminum include compounds represented by the following general formula: M 1 AlR j 4 (M 1 are Li, Na, and K, and R j is a hydrocarbon group having 1 to 15 carbon atoms.

[0067] Specific examples of such compounds include LiAl(C2H5)4, LiAl(C7H 15 )4 etc. These compounds can be used in combination of two or more kinds. The above R j is preferably a so-called hydrocarbon group containing only carbon and hydrogen.

[0068] In the present invention, the above-mentioned organoaluminum compound may be used in combination with other organometallic compounds as necessary. For example, in addition to trimethylaluminum and triethylaluminum, examples of organometallic compounds of Group 2 metals include compounds represented by the following general formula: R k R l M 2 (R k , R l are a hydrocarbon group having 1 to 15 carbon atoms or a halogen, and may be the same or different, except for the case where both are halogen. 2 are Mg, Zn, and Cd.)

[0069] Specific examples include diethyl zinc, diethyl magnesium, butylethyl magnesium, ethyl magnesium chloride, and butyl magnesium chloride. In this case, the ratio of the other aluminum compounds, calculated as metal atoms such as aluminum and magnesium, is preferably 50 mol % or less of the R3Al, more preferably 30 mol % or less, even more preferably 10 mol % or less, and particularly preferably 5 mol % or less.

[0070] The ethylene polymerization catalyst according to the present invention may be a catalyst in which olefins have been prepolymerized. The ethylene polymerization catalyst according to the present invention may contain other components useful for the polymerization of ethylene in addition to the above-mentioned components.

[0071] <Olefin Polymerization Method> In the ethylene polymerization method (main polymerization) according to the present invention, an olefin is polymerized in the presence of an ethylene polymerization catalyst comprising the above-mentioned solid titanium catalyst component (A) and organoaluminum compound (B). Specifically, a preferred embodiment is one in which ethylene is copolymerized with an olefin having 3 or more carbon atoms.

[0072] Specific examples of the olefins having 3 or more carbon atoms include α-olefins having 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, 4,4-dimethyl-1-hexene, 4-ethyl-1-hexene, 3-ethyl-1-hexene, 1-octene, 1-decene, 1-dodecene, 1-tetradecene, 1-hexadecene, 1-octadecene, and 1-eicosene. Furthermore, vinyl compounds, other unsaturated compounds, polyene compounds, etc. can also be copolymerized, and examples of such copolymers include 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; Cyclic olefins such as cyclopentene, cycloheptene, norbornene, 5-methyl-2-norbornene, tetracyclododecene, and 2-methyl-1,4,5,8-dimethano-1,2,3,4,4a,5,8,8a-octahydronaphthalene, and silane-based unsaturated compounds such as allyltrimethylsilane, allyltriethylsilane, 4-trimethylsilyl-1-butene, 6-trimethylsilyl-1-hexene, 8-trimethylsilyl-1-octene, and 10-trimethylsilyl-1-decene can also be copolymerized.

[0073] Two or more of the above olefins having 3 or more carbon atoms can also be copolymerized with ethylene. In the present invention, in the polymerization of ethylene, the solid titanium catalyst component (A) (or prepolymerization catalyst) is preferably used in an amount of usually about 0.0001 to 1.0 millimole in terms of titanium atom per liter of polymerization volume. The organoaluminum compound (B) is preferably used in an amount such that the aluminum atom in the catalyst component (B) is usually about 1 to 2,000 moles, preferably about 5 to 500 moles, per mole of titanium atom in the solid titanium catalyst component (A) in the polymerization system.

[0074] The polymerization can be carried out by either a liquid phase polymerization method such as solution polymerization or suspension polymerization, or a gas phase polymerization method. When the polymerization is carried out in the form of a slurry polymerization reaction, an organic solvent that is usually inert to polymerization is used as the polymerization solvent. Specifically, the organic solvent can be an aliphatic hydrocarbon such as propane, butane, pentane, hexane, heptane, octane, decane, dodecane, or kerosene, an alicyclic hydrocarbon such as cyclopentane, cyclohexane, or methylcyclopentane, an aromatic hydrocarbon such as benzene, toluene, or xylene, or a halogenated hydrocarbon such as ethylene chloride or chlorobenzene. These may be used in combination. Also, a copolymerization monomer that is liquid at the reaction temperature can be used together with the organic solvent.

[0075] The polymerization conditions vary depending on the type of polymerization or the type of ethylene polymer to be obtained, but the polymerization is usually carried out at a temperature of about 20 to 300°C, preferably about 50 to 150°C, under normal pressure to 100 kg / cm. 2 Preferably about 2 to 50 kg / cm 2 This is carried out under pressure.

[0076] The molecular weight of the polymer obtained can be adjusted by using hydrogen during the polymerization. The above-mentioned polymerization can be carried out by any of batch, semi-continuous, and continuous methods. Furthermore, the polymerization can be carried out in two or more stages by changing the reaction conditions.

[0077] In the present invention, when olefins are polymerized, a catalyst is formed using the specific solid titanium catalyst component (A) described above, which allows the production of a specific olefin polymer as described below with extremely high polymerization activity. The resulting ethylene polymer has a low catalyst content, particularly a low halogen content, per polymer unit, and is less likely to cause mold rust during molding. In addition, the ethylene polymer has a low fine powder content and is excellent in particle properties, so it may be used without pelletizing.

[0078] <Olefin polymer> The olefin polymer obtained by the process for producing an olefin polymer of the present invention is characterized by satisfying the following requirements. (PE1) the content of structural units derived from ethylene is 90 mol% or more and 99.8 mol% or less; (PE2) The content of structural units derived from olefins having 3 to 20 carbon atoms is 0.2 mol% or more and 10 mol% or less (however, the total of the structural units derived from ethylene and the structural units derived from olefins having 3 to 20 carbon atoms is 100 mol%). (D) Density is 900-960 kg / m 3 (H) Molecular weight determined by GPC measurement is 10 6.5 The content of the above components is 1.5 mass % or more.

[0079] The lower limit of the content of structural units derived from ethylene (PE1) is preferably 93 mass%, more preferably 95 mass%, and even more preferably 97 mass%, while the upper limit is preferably 99.5 mass%.

[0080] The lower limit of the content of the structural unit derived from an olefin having 3 to 20 carbon atoms (PE2) is preferably 0.5% by mass, while the upper limit is preferably 8% by mass, more preferably 6% by mass, and further preferably 5% by mass.

[0081] The content of the above olefin-derived structural units is 13NMR measurement is performed using a C NMR device, and peaks characteristic of the corresponding olefin are assigned in a conventional manner, and the content is determined by area quantification. Alternatively, IR measurement is performed on various olefin polymers having different compositions, and a calibration curve is prepared, so that the content of the olefin-derived structural unit can also be determined by IR measurement. In the examples of the present invention, the content of the olefin-derived structural unit is determined by the latter method using IR measurement.

[0082] (H) Molecular weight determined by GPC measurement is 10 6.5 The lower limit of the content of the above components is preferably 2.0 mass%, more preferably 2.2 mass%, even more preferably 2.5 mass%, particularly preferably 2.8 mass%, and especially preferably 3 mass%, while the upper limit is preferably 30 mass%, more preferably 25 mass%, even more preferably 22 mass%, and particularly preferably 20 mass%.

[0083] The GPC measurement conditions in the present invention are as follows. Apparatus: GPC-IRR type gel permeation chromatograph (Polymer Char) Detector (built-in): IR6 MCT infrared detector (Polymer Char) Detection wavelength: methylene sensor (2,920 cm -1 ), methyl sensor (2,960cm -1 ) Column: 2× TSKgel GMH6-HT + 2× TSKgel GMH6-HTL (7.5mm I.D.×30cm, Tosoh) Column temperature: 150℃ Mobile phase: o-dichlorobenzene (ODCB), with BHT Flow rate: 1.0mL / min Sample concentration: 10mg / 20mL (0.5mg / mL) Melting conditions: 145℃, 120min Sample filtration: 1.0 μm sintered filter Injection volume: 0.4mL Column calibration: Monodisperse polystyrene (TSKgel standard polystyrene; Tosoh) The above content can be obtained by analyzing the obtained chromatogram by a known method. In addition, since the above method also uses an FT-IR device, information such as branching in each molecular weight component can be obtained.

[0084] By using the method for producing an olefin polymer of the present invention, 6.5 Even in the case of a high molecular weight polymer exceeding the range of 1000 to 15000, it is possible to obtain a polymer having a relatively high content of structural units derived from olefins having 3 or more carbon atoms. In addition, the variation (variation) in the content of structural units derived from olefins having 3 or more carbon atoms due to molecular weight is relatively small. This can be confirmed by the above-mentioned method of combining GPC and FT-IR.

[0085] Molecular weight is 10 6.5 It is known that high molecular weight components in the range exceeding this molecular weight have excellent resistance to deformation, such as "impact resistance", but since olefins having 3 or more carbon atoms tend to have a slower reaction rate than ethylene, it appears that in the conventional methods for producing olefin polymers using olefin polymerization catalysts containing a solid titanium catalyst component, it has tended to be difficult to obtain high molecular weight olefin polymer components in the range of molecular weights exceeding 1 million, which have a relatively high content of structural units derived from olefins having 3 or more carbon atoms and / or little variation in said content depending on molecular weight (see Comparative Examples described below).

[0086] Olefin polymers containing olefin-derived structural units having 3 or more carbon atoms are considered to have a branched structure, and are polymers with a relatively low degree of crystallinity, which is expected to contribute to improving toughness. Therefore, components having a high molecular weight and relatively many branches as described above are preferred components that are expected to have multiple excellent properties such as impact resistance and toughness. Hereinafter, such components may be referred to as component (HB). Furthermore, it is preferable that the amount of branching is relatively stable regardless of the molecular weight of the olefin polymer. Such a tendency can be judged, for example, by whether the curve showing the relationship between molecular weight and branching in the GPC-IR measurement chart in Figure 1 is relatively gentle.

[0087] According to the investigations of the present inventors, the use of an olefin polymerization catalyst containing a specific organoaluminum compound tends to easily give a polymer containing the above-mentioned component (HB). Although the exact reason why an olefin polymer having such characteristics is obtained is unclear, the present inventors speculate as follows.

[0088] In solid titanium catalyst components having the above-mentioned ORa substituents or silicon-containing components, the reduction rate of titanium in the solid titanium catalyst component by organoaluminum compounds is relatively slow, so it is thought that the titanium forming the active site tends to maintain a trivalent or tetravalent state, which is considered to have relatively good copolymerizability, but this is probably not sufficient. (The catalyst disclosed in Patent Document 1 may have had a strong tendency in this regard.)

[0089] The organoaluminum compound of the present invention is used in combination with the solid titanium catalyst component, and the reduction rate of titanium as described above is further decreased, so that the active sites with high copolymerizability can exist more stably, which may make it easier to give olefin polymers containing the above-mentioned component (HB). In addition, the fact that the valence of the active sites is small is thought to allow the polymerization reaction to proceed stably, which may indicate a tendency to easily increase the molecular weight.

[0090] Other preferable physical properties of the olefin polymer obtained in the present invention include the following. The bulk density is desirably 0.20 to 0.60 g / cc, preferably 0.25 to 0.60 g / cc. The melt flow rate MFR (based on ASTS D1238E, 190° C.) is desirably 0.01 to 100 g / 10 min. The intrinsic viscosity [η] measured in decalin at 135° C. is preferably 1.5 to 10 dl / g, and more preferably 2.0 to 8 dl / g.

[0091] The olefin polymer, particularly the ethylene copolymer, obtained in the present invention has the above-mentioned structural characteristics, and therefore tends to have a high content of components that melt at low temperatures even if the content of olefins having 3 or more carbon atoms is similar. Such a tendency was confirmed by measuring the relationship between the ambient temperature and the heat of fusion by the DSC method described in the examples below, (β) Heat of fusion at 100℃ or less (γ) Heat of fusion at 125°C or higher can be checked as an indicator.

[0092] The ethylene copolymer produced by the method of the present invention tends to have a relatively large value of (β) and a relatively small value of (γ), which is believed to be because structural units derived from olefins having 3 or more carbon atoms are relatively dispersed and present in the ethylene copolymer (corresponding to a tendency for the composition distribution to be narrow).

[0093] The ethylene polymer obtained by the present invention as described above may also be blended with a heat stabilizer, a weather stabilizer, an antistatic agent, an antiblocking agent, a lubricant, a nucleating agent, a pigment, a dye, an inorganic or organic filler, etc., if necessary.

[0094] Within the above range, the polymer can be suitably used as a raw material for films, containers, etc. In particular, it is suitable as a raw material for containers obtained by blow molding, etc. EXAMPLES

[0095] The present invention will now be described in detail with reference to examples, but the present invention is not limited to these examples. In the following examples, the composition of the solid titanium catalyst component, the intrinsic viscosity [η] of the ethylene polymer, the bulk density, the density, and the butene content were measured as follows.

[0096] (1)Mg, Ti content The measurements were performed using an ICP analyzer (Shimadzu Corporation, ICPF 1000TR).

[0097] (2)Cl content It was measured by silver nitrate titration method.

[0098] (3) OR group content 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.

[0099] (4) Intrinsic viscosity [η] The intrinsic viscosity [η] was measured in decalin at 135° C. by dissolving the ethylene polymer in decalin and using a fully automatic viscosity measuring device (Rigosha, VMR-053UPC).

[0100] (5) Bulk density Measured according to JIS K 6721.

[0101] (6) Density Using a hydraulic heat press set at 190°C, the sample was heated and melted at a pressure of 5 MPa, then cooled at a pressure of 15 MPa and an average cooling rate of 15±5°C / min to produce a pressed sheet. (Spacer shape: 65×12×2 (mm) on a 200×200×2 (mm) thick plate, 4 pieces were cut.) The pressed sheet was boiled for 30 minutes, and then cooled together with the boiled water in a laboratory atmosphere for at least 1 hour, after which the density was measured using a density gradient tube.

[0102] (7) Content of butene-derived structural units The comonomer content of the copolymer was measured by FT-IR (FT-IR4100 infrared spectrophotometer manufactured by JASCO Corporation). For FT-IR, the copolymer produced in the examples was melt-stretched in a hot press heated to 180°C, and then cooled under pressure at room temperature to obtain a film, which was used as a measurement sample. -1 ~400cm -1 The butene content was measured by the C-CH2CH3 skeletal vibration (1378 cm -1Using this as the key band, the ratio [D1378 / D4321] of the absorbance (D1378) of the key band to the absorbance (D4321) of the internal standard band (4321 cm -1 : combined sound of C-H stretching vibration and methylene and methyl bending vibrations) was determined. On the other hand, for a plurality of ethylene / butene copolymers whose butene-derived structural unit content has been determined by methods such as 13 13C NMR in advance, the value of [D1378 / D4321] was obtained by the above method, and based on this, a calibration curve regarding the relationship between the [D1378 / D4321] value and the butene content was created. From this calibration curve and the measured values of [D1378 / D4321] using the polymers of the examples and comparative examples, the butene-derived structural unit content was determined.

[0103] In addition, DSC measurement and GPC-IR measurement of the ethylene polymer were carried out according to the following method. <DSC Measurement> A differential scanning calorimeter (DSC8000 manufactured by PerkinElmer) was used, and the SSA (Successive Self-Nucleation / Annealing) method described in European Polymer Journal 65 (2015) 132-154 was used. "Setting of Ts (Self-seeding and annealing) temperature" The temperature was raised from 20°C to 200°C at 25°C / min, held at 200°C for 5 minutes, then cooled from 200°C to 30°C at 25°C / min, held at 30°C for 2 minutes, and then raised from 20°C to 150°C at 10°C / min. The temperature at which the endothermic peak becomes zero above the melting point was set as the Ts temperature. "SSA (Successive Self-Nucleation / Annealing) method" The sample after Ts temperature measurement was heated from 20°C to 200°C at a rate of 25°C / min, held at 200°C for 5 minutes, then cooled from 200°C to 30°C at a rate of 25°C / min, held at 30°C for 2 minutes, heated from 30°C to the Ts temperature at a rate of 10°C / min, and held at the Ts temperature for 5 minutes. It was cooled from the Ts temperature to Ts - 35°C at a rate of 10°C / min, held at Ts - 35°C for 2 minutes, then heated from Ts - 35°C to Ts - 5°C at a rate of 10°C / min, and held at Ts - 5°C for 5 minutes. Next, it was cooled from Ts - 5°C to Ts - 40°C at a rate of 10°C / min, held at Ts - 40°C for 2 minutes, then heated from Ts - 40°C to Ts - 10°C at a rate of 10°C / min, and held at Ts - 10°C for 5 minutes. Such operations were repeated 11 times in 5°C increments. Finally, it was cooled from Ts - 55°C to 30°C at a rate of 10°C / min, held at 30°C for 2 minutes, and then heated from 30°C to 200°C at a rate of 10°C / min. Let the total heat of fusion calculated from the obtained heat absorption peak of fusion be ΔH, the heat of fusion above 125°C be ΔH125, and the heat of fusion below 100°C be ΔH100. Then, The crystal component ratio above 125°C = (ΔH125 / ΔH) × 100% The crystal component ratio below 100°C = (ΔH100 / ΔH) × 100% was calculated as such.

[0104] <GPC - IR Measurement> Apparatus: GPC - IRR type gel permeation chromatograph (Polymer Char) Detector (built - in): IR6 MCT infrared detector (Polymer Char) Detection wavelength: Methylene sensor (2,920 cm -1 ), Methyl sensor (2,960 cm -1 ) Column: 2 × TSKgel GMH6 - HT + 2 × TSKgel GMH6 - HTL (7.5 mm I.D. × 30 cm, Tosoh) Column temperature: 150°C Mobile phase: o - dichlorobenzene (ODCB), with BHT added Flow rate: 1.0 mL / min Sample concentration: 10 mg / 20 mL (0.5 mg / mL) Dissolution conditions: 145°C, 120 min Sample filtration: 1.0 μm sintered filter Injection volume: 0.4mL Column calibration: Monodisperse polystyrene (TSKgel standard polystyrene; Tosoh)

[0105] [Synthesis Example 1] "Preparation of solid titanium catalyst component (A)" The solid titanium catalyst component (A) was prepared in the same manner as in the Examples of JP-A-9-328514. The composition of the obtained solid titanium catalyst component (A) is shown in Table 1.

[0106] [Example 1] In a 1-liter autoclave, 500 ml of purified n-heptane was charged under a nitrogen atmosphere, and 0.78 mmol of triisobutylaluminum (molecular weight of isobutyl group: 57.12) and the decane suspension of the solid titanium catalyst component (A) obtained above were added in an amount equivalent to 0.03 mmol of titanium atom. The mixture was heated to 72°C with stirring, and hydrogen diluted with nitrogen to a hydrogen concentration of 5 mol% was fed at 0.01 MPa, followed by continuous feeding of an ethylene butene mixed gas with a butene concentration of 2 mol% to a total pressure of 0.10 MPaG. The polymerization temperature was maintained at 72°C. After the polymerization was completed, the ethylene polymer was separated from the n-heptane solvent and dried. After drying, 24.2 g of a powdery polymer was obtained. The intrinsic viscosity [η] of this powdery polymer was 7.6 dl / g and the density was 926 kg / m 3 The butene content was 6.9 / 1000C and the apparent bulk density was 0.29g / cc. The results are shown in Table 2. The DSC analysis results and GPC-IR analysis results of this powdery polymer are shown in Table 2, and the GPC-IR measurement chart is shown in Figure 1.

[0107] [Example 2] Polymerization was carried out in the same manner as in Example 1, except that triisobutylaluminum was changed to diethylaluminum chloride (atomic weight of chlorine: 35.453) during polymerization. The results are shown in Table 2.

[0108] [Example 3] Polymerization was carried out in the same manner as in Example 1, except that hydrogen diluted with nitrogen to a hydrogen concentration of 5 mol % was supplied at 0.05 MPa, and then an ethylene-butene mixed gas having a butene concentration of 2 mol % was continuously supplied so that the total pressure became 0.14 MPaG. The results are shown in Table 2.

[0109] [Example 4] Polymerization was carried out in the same manner as in Example 2, except that hydrogen diluted with nitrogen to a hydrogen concentration of 5 mol % was supplied at 0.10 MPa, and then an ethylene-butene mixed gas having a butene concentration of 2 mol % was continuously supplied so that the total pressure became 0.19 MPaG. The results are shown in Table 2.

[0110] [Comparative Example 1] Polymerization was carried out in the same manner as in Example 1, except that triethylaluminum was used instead of triisobutylaluminum during polymerization. The results are shown in Table 2, and the GPC-IR measurement chart is shown in FIG.

[0111] [Synthesis Example 2] "Preparation of solid titanium catalyst component (B)" The solid titanium catalyst component (B) was prepared in the same manner as in the Examples of WO 2009 / 125729. The composition of the obtained solid titanium catalyst component (B) is shown in Table 1.

[0112] [Example 5] Polymerization was carried out in the same manner as in Example 1, except that the solid titanium catalyst component (A) used in polymerization was changed to the solid titanium catalyst component (B). The results are shown in Table 2.

[0113] [Comparative Example 2] Polymerization was carried out in the same manner as in Example 5, except that triisobutylaluminum was changed to triethylaluminum (molecular weight of ethyl group: 29.06) during polymerization. The results are shown in Table 2.

[0114] [Synthesis Example 3] "Preparation of solid titanium catalyst component (C)" The solid titanium catalyst component (C) was prepared in the same manner as in the Examples of WO 2008 / 013144. The composition of the obtained solid titanium catalyst component (C) is shown in Table 1.

[0115] [Example 6] Polymerization was carried out in the same manner as in Example 1, except that the solid titanium catalyst component (A) used in the polymerization was changed to the solid titanium catalyst component (C). The results are shown in Table 2.

[0116] [Comparative Example 3] Polymerization was carried out in the same manner as in Example 6, except that triethylaluminum was used instead of triisobutylaluminum during polymerization. The results are shown in Table 2.

[0117] [Table 1]

[0118] [Table 2]

[0119] As shown in FIG. 1, the olefin polymer obtained by using the olefin polymerization catalyst of the present invention has a molecular weight of 10 6.5 It is clear that even in the high molecular weight region, the polymer has a relatively high structural unit number of 3 or more carbon atoms, and the content is relatively constant regardless of the molecular weight.

Claims

1. (A) Containing magnesium, titanium, and halogens, Magnesium in 10-25% by mass, Titanium in 2-12 mass%, The ORa group is 1 to 12% by mass (where Ra is a hydrocarbon group having 1 to 20 carbon atoms), and (α) A compound selected from silicon-containing compounds, organic acid compounds, organic acid ester compounds, ketone compounds, aldehyde compounds, nitrogen-containing compounds, and phosphorus-containing compounds in an amount of 0 to 12% by mass. A solid titanium catalyst component containing, (B) Organic aluminum compounds defined by the following formula (1) and R 3 Al・・・(1)) (However, R is a substituent selected from the group including hydrocarbon groups having 1 to 20 carbon atoms and halogen atoms, and one or more of these substituents have a molecular weight of 30 or more.) A method for producing an olefin polymer that satisfies the following requirements (PE1), (PE2), (D), and (H) by polymerizing an olefin in the presence of an olefin polymerization catalyst containing: (PE1) The structural unit content derived from ethylene is 90 mol% or more and 99.8 mol% or less; (PE2) The content of structural units derived from olefins having 3 to 20 carbon atoms is 0.2 mol% or more and 10 mol% or less (provided that the total of structural units derived from ethylene and structural units derived from olefins having 3 to 20 carbon atoms is 100 mol%); (D) Density of 900-960 kg / m³ 3 ; (H) Molecular weight determined by GPC measurement is 10 6.5 The content of the above components is 1.5% by mass or more.

2. A method for producing an olefin polymer according to claim 1, wherein one or more of the R in formula (1) has a molecular weight of 35 or more and 300 or less.

3. A method for producing an olefin polymer according to claim 1, wherein one or more of the R in formula (1) is a hydrocarbon group consisting of a carbon atom and a hydrogen atom.

4. The method for producing an olefin polymer according to claim 1, wherein the (A) solid titanium catalyst component is obtained by contacting (a) a liquid magnesium compound and (b) a liquid titanium compound in the presence of (c) an organosilicon compound that does not contain active hydrogen in an amount of 0.25 to 0.35 moles per mole of the magnesium compound (a), raising the temperature of the resulting contact (i) to a temperature in the range of 105 to 115°C and maintaining it at this temperature.

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