KR100247733B1 - Preparing process of catalyst for polyolefin polymerization - Google Patents

Abstract

The present invention relates to a method for producing a polyolefin polymerization catalyst, and more specifically, halogen-containing organosilane compound is added to a homogeneous solution containing an oxygen-containing magnesium compound, a transition metal compound, an oxygen-containing organic titanium compound and an active hydrogen-containing organic compound. To recover a spherical particulate carrier, and to add a transition metal compound and an internal electron donor to the recovered carrier to produce a polyolefin polymerization catalyst. As a result, in the presence of the catalyst of the present invention, it is possible to produce a polyolefin having excellent powder properties and very good stereoregularity.

Description

Method for producing polyolefin polymerization catalyst

The present invention relates to a method for producing a polyolefin polymerization catalyst, and more specifically, halogen-containing organosilane compound is added to a homogeneous solution containing an oxygen-containing magnesium compound, a transition metal compound, an oxygen-containing organic titanium compound and an active hydrogen-containing organic compound. To recover a spherical particulate carrier, and to add a transition metal compound and an internal electron donor to the recovered carrier to produce a polyolefin polymerization catalyst. As a result, in the presence of the catalyst of the present invention, it is possible to produce a polyolefin having excellent powder properties and very good stereoregularity.

Known catalysts for alpha olefin polymerization include titanium trichloride, metallocene catalysts and magnesium supported catalysts. Titanium trichloride catalyst (Korean Patent Publication No. 94-10961) has a disadvantage in that the polymerization activity is low and the catalyst residue is left in the polymer, so that the catalyst residue removal process must be added separately. The metallocene catalyst is a catalyst for preparing a high active high-stereoregular polymer, which has been actively studied in recent years, but is still being developed commercially for the production of some special grades.

Magnesium-supported catalysts exhibit high activity and high stereoregularity in propylene polymerization. High catalytic activity enables the production of polyolefins without removing catalyst residues, and high stereoregularity is atactic polymer. ) And improve the physical properties of the resulting polymer.

Magnesium-supported catalysts have been proposed in which a solid component comprising at least magnesium, titanium, and halogens (particularly chlorine) and a solid component combined with an organoaluminum compound are activated and used as an olefin polymerization catalyst. In addition, an electron donor (Lewis base) is added to these catalyst compositions as a component that enhances stereoregularity. Therefore, the magnesium-supported catalyst is basically composed of a titanium-magnesium-containing catalyst, an organoaluminum-based cocatalyst, and an electron donor. Among them, a number of patents have been filed with the titanium-magnesium-containing component as the main catalyst.

Such titanium-magnesium-containing catalysts include magnesium chloride [Korean Patent Publication Nos. 94-6215, 94-10963], magnesium alkyl [Korean Patent Publications No. 95-7985, 95-9109], magnesium alkoxides [ Korean Patent Publication Nos. 94-8348 and 94-10331] and magnesium metal (Korean Patent Publication Nos. 94-4124 and 94-3857) are used as starting materials to support titanium. Many polyolefin polymerization catalysts currently used are known to be prepared by a method of starting a magnesium alkoxide as a starting material and reacting it with titanium tetrachloride and an internal electron donor [Korean Patent Publication Nos. 82-1309, 83-1349, U.S. Patent 4,329,253, U.S. Patent 4,393,182, U.S. Patent 4,547,476, European Patent 361,371]. However, in such a catalyst, catalyst particles are determined according to the form of magnesium alkoxide used in the production process, and the particle form of the polyolefin is also copied after polymerization. In other words, these catalysts break down magnesium alkoxide particles by a pulverizer, etc. during the production of the catalyst, and when they are polymerized, they are duplicated in the polymer to produce an uneven polymer, which causes a problem of transport during the process operation. Is pointed out.

Recent patents have introduced techniques for the production of catalysts with uniform particles, the main focus of which is to re-crystallize the magnesium carriers into spheres of uniform size. That is, when the carrier is obtained through a recrystallization process during the preparation of the catalyst, it is possible to prepare a catalyst having excellent particle shape and narrow particle size distribution. These methods include a method of granulation using a spray dryer [Korean Patent Publication No. 95-6120, US Patent No. 4,465,783] and a method of dissolving magnesium alkoxide in alcohol by treating carbon dioxide and recrystallizing it. Publication Nos. 94-10331, 95-6120, U.S. Patent No. 4,946,816, and methods of recrystallization after dissolving in oxygen-containing titanium and alcohol compounds are also disclosed (US Pat. Nos. 5,077,357, 5,066,737).

A good polymer should be uniform in particle size and shape, wear resistant and have an apparent density higher than the appropriate value. In particular, if the particle size of the polymer is too large, there is a problem in the transfer, in the case of very small particles to block the dryer filter during the operation of the slurry process and the particles are dissolved in a solvent with the atactic polymer is low productivity.

Therefore, the inventors of the present invention provide a method of recrystallization of magnesium compounds to support a high-active magnesium that produces a polymer having a low apparent density, a uniform particle shape of the polymer, a particle size and a particle size control, and a low particle content suitable for a slurry process. Efforts have been made to develop type catalysts. As a result, the present inventors have already added the halogen-containing organosilane compound to the homogeneous solution containing the magnesium compound and the oxygen-containing organotitanium compound in Korean Patent Application No. 97-17545 to produce a carrier precipitate, The carrier was recrystallized using a cyclic ether compound to recover the carrier having excellent particle shape and narrow particle size distribution. In addition, by adding a transition metal compound and an internal electron donor to the recovered support, a polymerization catalyst having high activity (2000 g-PP / g-catalyst), excellent stereoregularity (more than 98% of isotactic index) and good particle characteristics It has been filed for a method of manufacturing.

However, the Republic of Korea Patent Application No. 97-17545 is required to further improve the polymerization activity and particle characteristics, and the present inventors have a further improved polymerization activity and particle characteristics while maintaining the high stereoregularity of the catalyst system The preparation method of the polymerization catalyst component which can provide a polymer was studied.

Therefore, in the present invention, the catalyst activity was increased by the pretreatment reaction with the transition metal compound in the initial stage of the catalyst manufacturing process, and the spherical particles having the appropriate size in the recrystallization process using the oxygen-containing organotitanium compound and wasteols in the preparation of the homogeneous solution. By recovering the carrier, the Ziegler-Natta is suitable for the sale of powders because of its uniform particle size distribution, moderate apparent density, low content of fine particles and uniform particle shape. It is an object of the present invention to provide a method for preparing a Ziegler-Natta) solid polymer catalyst.

1 is an electron micrograph (SEM) photograph (× 300) of the polymer prepared in Example 1,

2 is an electron microscope (SEM) photograph (x300) of the polymer prepared in Comparative Example 3.

In the production method of magnesium-supported polymerization catalyst used for the production of polyolefin,

(i) mixing a transition metal compound (b) with an oxygen-containing magnesium compound (a) and performing partial pretreatment at 70 to 110 ° C;

(ii) preparing a homogeneous solution by adding an oxygen-containing organic titanium compound (c) and an active hydrogen-containing organic compound (d) to the pretreatment reactant;

(iii) adding a halogen-containing organosilane compound (e) to the homogeneous solution to form a precipitate, and recovering the precipitated spherical particulate carrier from the reaction solution; And

(iv) a method for producing a polyolefin polymerization catalyst comprising the step of preparing a solid polymerization catalyst by treating the carrier with a transition metal compound (b) and an internal electron donor (f).

Referring to the present invention in more detail as follows.

The present invention relates to a method for producing a polymerization catalyst having excellent properties such as being used as a catalyst in the polymerization of alpha olefins having 3 or more carbon atoms to enable uniform particle size and control of particle size.

Referring to the manufacturing process of the polymerization catalyst according to the present invention in more detail by each process as follows.

In the first production process, oxygen-containing magnesium compound (a) is reacted with a small amount of transition metal compound (b), preferably titanium halide, in an inert gas atmosphere, which is a very important step in the preparation of the catalyst. The proper pretreatment reaction with such a titanium halide has a great influence on the polymerization activity and particle shape of the prepared catalyst. When not pretreated with titanium halide (see Comparative Example 4), the catalytic activity is significantly lowered, the particle shape is uneven, and the number of fine particles is high.

The oxygen-containing magnesium compound (a) and the transition metal compound (b) are mixed to raise the temperature of the mixture to 70 to 110 ° C. over 10 to 40 minutes. At this time, the mixing ratio of the transition metal compound (b) to the oxygen-containing magnesium compound (a) is 0.05 to 1.0 molar ratio, preferably 0.1 to 0.6 molar ratio.

In the second manufacturing process, an oxygen-containing organic titanium compound (c) and an active hydrogen-containing organic compound (d) are added to the pretreatment reactant to prepare a homogeneous solution.

At this time, the oxygen-containing organic titanium compound (c) to the oxygen-containing magnesium compound (a) is used in 0.1 to 1.0 molar ratio, preferably 0.15 to 0.60 molar ratio, the active hydrogen-containing organic compound to the oxygen-containing magnesium compound (a) (d) is used in 0.1-4.0 molar ratio, Preferably it is 1.0-2.0 molar ratio. The reaction temperature is carried out for 1 to 5 hours, preferably 1 to 3 hours at 0 ℃ to 150 ℃ preferably 70 ℃ to 110 ℃ to obtain a uniform solution. The amount of the oxygen-containing organic titanium compound to be added should be at least 0.1 molar ratio with respect to the oxygen-containing magnesium compound (a), whereby the active hydrogen-containing organic compound is added to facilitate dissolution. In addition, with respect to the oxygen-containing organic titanium compound (c), the transition metal compound (b) should be used within the range of 0.25 to 0.06 molar ratio to obtain a carrier having an appropriate particle size. If the ratio is less than 0.25 molar ratio, the average particle diameter This is because it becomes large rapidly, and if it exceeds 0.60 molar ratio, since catalyst activity will fall rapidly, it is unpreferable (refer comparative example 1 and comparative example 2). In addition, when a catalyst prepared without adding the oxygen-containing organotitanium compound (c) is used, the shape of the polymer particles is poor and the average particle diameter is rapidly increased (see Comparative Example 5). In this process, when the active hydrogen-containing organic compound (d) is not added, the polymerization activity of the polymer is high, but the particle shape of the polymer is irregular, and the particle ratio increases slightly with decreasing stereoregularity (see Comparative Example 3). ).

The most important point of the catalyst preparation process of the present invention is a process of obtaining a precipitated spherical particulate carrier by adding a halogen-containing organosilane compound (e) as a third process. When the catalyst prepared without this step is used, the apparent density of the polymer is significantly lowered, and the particulate content is rapidly increased (see Comparative Example 6). When the halogen-containing organosilane compound (e) is added to the homogeneous solution obtained above and the reaction is carried out, a carrier is formed. At this time, the homogeneous solution is cooled to room temperature and then the silane compound is added dropwise. It is very important that the cargo is slowly loaded with sufficient time. The dropping of the silane compound (dimethyldichlorosilane) during the formation of the carrier not only causes the shape of the polymer particles to become a spherical shape but also reduces the particulate content. When the silane compound is dropped at a time, non-uniform particles are formed by a sudden reaction. The dropping time is 1 to 12 hours, preferably 1 to 4 hours. The silane compound with respect to the magnesium compound is used in a 0.5 to 10 molar ratio, preferably 1 to 3 molar ratio, the reaction temperature is 0 ~ 100 ℃, preferably in the range of 50 ℃ at room temperature, the reaction is carried out in an inert gas atmosphere silane As the compound continues to drop, small particles are produced uniformly.

The solid product obtained here is usually filtered or decanted to remove unreacted substances and by-products, thoroughly washed with an inert organic solvent and then suspended in an inert organic solvent. The obtained solid support consists of 10-30 wt% of magnesium, 0.5-4.0 wt% of titanium, and a small amount of less than 1.0 wt% of 65-80 wt% of halogen.

In the fourth manufacturing process, the magnesium compound (a) is converted into a magnesium halide by reacting the excess transition metal compound (b) in an inert atmosphere, and reacting in the presence of a suitable internal electron donor (f) to obtain stereospecificity. Have it.

The internal electron donor (f) is used in the range of about 0.001 to 1.0 molar ratio, preferably 0.01 to 0.8 molar ratio with respect to the magnesium compound (a), and the amount of the internal electron donor (f) is an important factor for determining the stereospecificity of the polymer. do. At this time, the reaction conditions are 0 to 200 ℃, preferably at 80 to 130 ℃ temperature for 1 to 24 hours, preferably 2 to 6 hours. Thereafter, the supernatant is decanted, washed with an organic solvent, and then subjected to a two-step treatment with a titanium halide compound, wherein the treatment conditions are 1 to 24 hours at 0 to 200 ° C, preferably 80 to 130 ° C, preferably Reacts for 2 to 6 hours to obtain a polymerization catalyst.

When the reaction conditions are out of the above-described ranges of reaction, the polymerization activity of the catalyst is low or the powder properties of the polymer are poor, for example, the amount of the polymer having a fine particle size or the amount of the polymer having a large particle size is increased, or the polymer obtained. A problem arises in that the particle size distribution of the particles is wide and the shape of the polymer particles is uneven. Therefore, in order to obtain a polymer having a uniform shape and to have a high polymerization activity of the catalyst, it is very important to prepare a polymerization catalyst component in a specific molar ratio and not to deviate from the molar ratio in the above general range.

The unreacted substance contained in the prepared polymerization catalyst component should be removed. The removal process is performed by removing the organic solvent and incomplete reactant used in the preparation of the catalyst with a suitable solvent such as liquid hydrocarbon or hydrocarbon chloride, preferably the catalyst component. It is washed several times with a nonpolar solvent such as hexane which does not react with. The chemical structure of the polymerization catalyst produced by the above manufacturing process is not yet known, but the constituents are 1 to 4% by weight of titanium, 15 to 30% by weight of magnesium, 60 to 80% by weight of halogen and 1.0% by weight of Si. It is present in smaller amounts.

Referring to each component used in the polymerization catalyst preparation according to the present invention as described above in more detail as follows.

As the organic solvent used in the preparation of the catalyst of the present invention, an aliphatic or aromatic hydrocarbon or a halogen derivative thereof or a mixture thereof may be mentioned. Pentane, isopentane, hexane, cyclohexane, heptane, octane, nonane, decane, benzene, toluene, xylene, chlorobenzene, 1,2-dichlorobenzene, 1,3-dichlorobenzene, 1,2-dichloroethane And the like, and these organic solvents may be used alone or in combination as a mixture. As an organic solvent, Preferably, an aromatic hydrocarbon is used, Especially preferably, toluene and chlorobenzene are used.

The magnesium compound (a) in the present invention is selected from the group consisting of a compound of magnesium metal and a hydroxyl organic compound and an oxygen-containing organic compound of magnesium. In the formula, Mg (OR ¹ ) _n X _2-n ( _wherein R ¹ is a hydrocarbon group having 2 to 8 carbon atoms, X is a halogen atom, and n is an integer satisfying 0≤n≤2). Can be displayed. Specific examples of the magnesium compound (a) include magnesium halides such as magnesium chloride, magnesium bromide, magnesium iodide and magnesium fluoride; Alkoxyhalogenated magnesiums such as methoxymagnesium chloride, ethoxymagnesium chloride, isopropoxy magnesium chloride, butoxy magnesium chloride, and octoshima magnesium chloride; Halogenated aryloxymagnesium, such as magnesium phenoxy chloride and halogenated methylphenoxy magnesium; Alkoxy magnesium, such as ethoxy magnesium, isopropoxy magnesium, butoxy magnesium, n-octoxy magnesium, and 2-ethyl hexamethane magnesium; Aryloxymagnesium, such as phenoxy magnesium and dimethylphenoxy magnesium; It is a single compound or mixture of 2 or more types chosen from the carboxylic acid salts of magnesium, such as magnesium laurate and magnesium stearate. Preferably, alkoxymagnesium is used, and ethoxymagnesium is particularly preferable.

In the present invention, titanium halide is used as the transition metal compound (b). Specific examples thereof include tetravalent titanium compounds such as titanium tetrahalides such as titanium tetrachloride, titanium tetrabromide and titanium tetraiodide; Trivalent titanium compounds such as titanium trichloride, titanium tribromide, titanium triiodide and the like. Among them, the use of liquid titanium tetrachloride is most suitable for producing the high activity polyolefin catalyst as in the present invention. Moreover, the said tetravalent titanium compound and the trivalent titanium compound can also be mixed and used.

n≤4을 만족하는 정수)으로 표시될 수 있다. 산소함유 유기티타늄화합물(c)의 구체적인 예로는 메톡시티타늄 트리클로라이드, 에톡시티타늄 트리클로라이드, n-프로톡시티타늄 트리클로라이드, 이소프로폭시티타늄 트리클로라이드, n-부톡시티타늄 트리클로라이드, 이소부톡시티타늄 트리클로라이드, 에톡시티타늄 트리브로마이드, n-프로폭시티타늄 트리브로마이드, 이소프로폭시티타늄 트리브로마이드, n-부톡시티타늄 트리브로마이드, 이소부톡시티타늄 트리브로마이드 등의 알콕시티타늄 트리할라이드류; 디메톡시티타늄 디클로라이드, 디에톡시티타늄 디클로라이드, 디n-프로폭시티타늄 디클로라이드, 디이소프로폭시티타늄 디클로라이드, 디n-부톡시티타늄 디클로라이드, 디이소부톡시티타늄 디클로라이드, 디에톡시티타늄 디브로마이드, 디n-프로폭시티타늄 디브로마이드, 디이소프로폭시티타늄 디브로마이드, 디n-부톡시티타늄 디브로마이드 및 디이소부톡시티타늄 디브로마이드 등의 디알콕시티타튬 디할라이드류; 트리메톡시티타늄 클로라이드, 트리에톡시티타늄 클로라이드, 트리n-프로폭시티타늄 클로라이드, 트리이소프로폭시티타늄 클로라이드, 트리n-부톡시티타늄 클로라이드, 트리이소부톡시티타늄 클로라이드, 트리에톡시티타늄 브로마이드, 트리n-프로폭시티타늄 브로마이드, 트리이소프로폭시티타늄 브로마이드, 트리n-부톡시티타늄 브로마이드 및 트리이소부톡시티타늄 브로마이드 등의 트리알콕시 티타늄 할라이드류; 테트라메톡시티타늄, 테트라에톡시티타늄, 테트라n-프로폭시티타늄, 테트라이소프로폭시티타늄, 테트라n-부톡시티타늄, 테트라이소부톡시티타늄, 테트라2-에틸헥속시티타늄 등의 테트라알콕시티타늄류 등을 들 수 있다.Oxygen-containing organotitanium compound (c) suitable for use in the present invention is Ti (OR ² ) _n X _4-n ( _wherein R ² represents an alkyl group of 1 to 20, X is a halogen atom, n is 0

an integer satisfying n ≦ 4). Specific examples of the oxygen-containing organotitanium compound (c) include methoxytitanium trichloride, ethoxytitanium trichloride, n-propoxytitanium trichloride, isopropoxytitanium trichloride, n-butoxytitanium trichloride, isobutoxytitanium Alkoxytitanium trihalides such as trichloride, ethoxy titanium tribromide, n-propoxytitanium tribromide, isopropoxytitanium tribromide, n-butoxytitanium tribromide and isobutoxytitanium tribromide; Dimethoxytitanium dichloride, diethoxytitanium dichloride, din-propoxytitanium dichloride, diisopropoxytitanium dichloride, din-butoxytitanium dichloride, diisobutoxytitanium dichloride, diethoxytitanium dibromide Dialkoxytitanium dihalides such as din-propoxytitanium dibromide, diisopropoxytitanium dibromide, din-butoxytitanium dibromide and diisobutoxytitanium dibromide; Trimethoxytitanium chloride, triethoxytitanium chloride, trin-propoxytitanium chloride, triisopropoxytitanium chloride, trin-butoxytitanium chloride, triisobutoxytitanium chloride, triethoxytitanium bromide, trin- Trialkoxy titanium halides such as propoxytitanium bromide, triisopropoxytitanium bromide, trin-butoxytitanium bromide and triisobutoxytitanium bromide; Tetraalkoxytitaniums such as tetramethoxytitanium, tetraethoxytitanium, tetran-propoxytitanium, tetraisopropoxytitanium, tetran-butoxytitanium, tetraisobutoxytitanium and tetra2-ethylhexoxytitanium Can be mentioned.

These titanium compounds may be used alone or in combination of two or more thereof. When used alone, tetraalkoxytitaniums are suitable, and tetraethoxytitanium is most preferable.

As the active hydrogen-containing organic compound (d) used in the synthesis of the present invention, alcohol, phenols, thiols, and amines represented by the general formula R ³ OH (wherein R ³ is a hydrocarbon group having 1 to 12 carbon atoms) , Aldehydes, organic acids and amides of organic acids, including alcohols and phenols are preferred. Specific examples of the alcohols include methanol, ethanol, n-propyl alcohol, i-propyl alcohol, n-butyl alcohol, i-butyl alcohol, s-butyl alcohol t-butyl alcohol, n-amyl alcohol, i-amyl alcohol, hexyl Substituted groups such as saturated aliphatic alcohols such as alcohol, heptyl alcohol, octyl alcohol, 2-ethyl hexyl alcohol, nonyl alcohol, decyl alcohol, undecyl alcohol, dodecyl alcohol, aryl alcohol, crotyl alcohol, propargyl alcohol, etc. Aromatic alcohols such as alcohol, benzyl alcohol, methyl benzyl alcohol, ethyl benzyl alcohol, n-propyl benzyl alcohol, di-n-propyl benzyl alcohol and the like. Phenols contain 6-18 carbon atoms such as phenol, o-cresol, m-cresol, p-cresol, xylenol, 2,6-dimethylphenol, butylphenol, octylphenol, dibutylphenol, cumylphenol and naphthol Phenol to be included in this. Most preferred are phenols, among which m-cresol is most suitable.

As the organosilane compound (e), a compound usable in the present invention is of general formula SiR ³ _p X _4-p , wherein R ³ represents an alkyl or alkoxyl group having 1 to 8 carbon atoms, X represents a halogen atom, and p Is an integer satisfying 0 ≦ p ≦ 3).

For example, tetrachlorosilane, methyltrichlorosilane, dimethyldichlorosilane, diethyldichlorosilane, trichloromethoxysilane, dimethoxydichlorosilane, trichloroethoxysilane, and the like, of which dimethyldichlorosilane is most suitable. .

As the internal electron donor (f), ethers, esters, amines, alcohols, phenols, aldehydes, ketones, amine oxides, amides, thiols and the like can be used, and these can be used alone or in combination. Examples of the ether include aliphatic ethers having 4 to 24 carbon atoms; And cyclic ethers having 3 to 4 carbon atoms, aromatic or alkylaromatic ethers having 7 to 15 carbon atoms, and the like. For example, diethyl ether, diisopropyl ether, dibutyl ether, diamyl ether, dihexyl ether, dioctyl ether, dioxane, tetrahydrofuran, 1,3-propylene oxide, diphenyl ether, anisole, etc. to be.

Aromatic mono or dialkyl esters of 1 to 6 carbon atoms, dicarboxylic acids, substituted aromatic mono or dicarboxylic acids may also be used, for example methyl benzoate, methyl bromobenzoate, ethyl benzoate. And ethyl chlorobenzoate, ethyl bromobenzoate, cyclohexyl benzoate and the like. The most preferable of these are anti-aromatic esters, in particular, dialkyl phthalate containing an alkyl group having 2 to 10 carbon atoms, for example diethyl phthalate, din-butyl phthalate, diisobutyl phthalate, ethyl butyl phthalate, di t -A single compound or a mixture of two or more selected from -butyl phthalate.

Solid polymerization catalysts prepared by the process described above are useful for the polymerization of alpha olefins, such as ethylene and propylene, in particular with propylene, butene-1, pentene-1, 4-methylpentene-1 and hexene-1; It is useful not only for alpha olefin powders containing the same 3 or more carbon atoms but also mixtures thereof and copolymerization with ethylene. Such a polymerization catalyst is effective to copolymerize ethylene or higher olefins in propylene to 10 mol% or less, and is particularly preferable for propylene homopolymerization.

Polymerization of the alpha olefins using the polymerization catalyst of the present invention prepared by the above production process is as follows.

At this time, the polymerization reaction is prepared by contacting propylene with the catalyst composition according to the present invention under certain conditions. Such conditions include polymerization temperature and time, monomer pressure, slurry polymerization medium, hydrogen to control polymer molecular weight, and the like.

r≤3을 만족하는 정수)으로 표시되는 유기금속화합물을 사용하여 포화 탄화수소 용매의 존재하에서 소량의 프로필렌과 접촉하여 중합을 시킨다. 상기 유기금속화합물의 구체적인 예로는 트리알킬알루미늄 특히, 트리에틸알루미늄, 트리이소부틸알루미늄 또는 이들의 혼합물이 사용 되어진다. 필요한 경우, 1개 이상의 할로겐을 갖는 알킬알루미늄, 예를 들면 에틸알루미늄 디클로라이드, 디에틸알루미늄 디클로라이드, 에틸알루미늄 세스퀴클로라이드 등이 사용될 수 있다. 이들 유기금속화합물은 중합반응에 의해 생성되는 중합체에 대하여 0.1~20 중량비, 바람직하게는 1~8 중량비 범위로 사용하고, 또한 중합촉매 성분중에 함유된 티타늄원자에 대한 알루미늄 원자비율이 약 10~500 원자비, 바람직하기로는 약 30~300 원자비를 이루는 것이다.In the polymerization process of the polyolefin according to the present invention, in addition to the polymerization catalyst prepared above, MR ⁵ _r X _3-r (wherein M represents an organometallic group IA, IIA, IIB, IIIB or IVB of the periodic table, R ⁵ Represents a straight, branched or cycloalkyl group having 1 to 10 carbon atoms, X represents a halogen atom and r is 0

The organometallic compound represented by r < 3 < 3) is used to make polymerization by contacting a small amount of propylene in the presence of a saturated hydrocarbon solvent. Specific examples of the organometallic compound include trialkylaluminum, in particular triethylaluminum, triisobutylaluminum or mixtures thereof. If desired, alkylaluminums having one or more halogens such as ethylaluminum dichloride, diethylaluminum dichloride, ethylaluminum sesquichloride, and the like can be used. These organometallic compounds are used in the range of 0.1 to 20 weight ratios, preferably 1 to 8 weight ratios, based on the polymer produced by the polymerization reaction, and the aluminum atomic ratio to the titanium atoms contained in the polymerization catalyst component is about 10 to 500 Atomic ratios, preferably about 30 to 300 atomic ratios.

In addition, in the polymerization reaction, in order to maximize catalyst activity and stereospecificity, it is preferable to incorporate an external electron donor such as silane, inorganic acid, hydrogen sulfide, organic acid, organic acid ester, or a mixture thereof. As such external electron donors, it is preferable to use silanes containing alkyl, aryl and alkoxy groups, and specific examples thereof include diphenyldimethoxysilane, phenyltrimethoxysilane, isobutyltrimethoxysilane and diisobutyldimethoxy. Silane and cyclohexylmethyldimethoxysilane. The external electron donor is used in 1 to 40 molar ratio, preferably 5 to 30 molar ratio with respect to the catalyst component used in the polymerization.

In the present invention, the olefin polymerization is carried out in a slurry phase. Suitable solvents for use in this case are inert hydrocarbon solvents. Specific examples of these inert hydrocarbons include linear or branched aliphatic hydrocarbons such as propane, butane, pentane, hexane, heptane, octane, decane, dodecane and kerosene; Cyclic hydrocarbons such as cyclopentane, cyclohexane and methylcyclopentane; Aromatic hydrocarbons such as benzene, toluene and xylene; Halogenated hydrocarbons such as ethylene chloride and chlorobenzene, and mixtures thereof. Among these inert hydrocarbon solvents, aliphatic hydrocarbons are preferable, and hexane, heptane and the like are most suitable in consideration of economic and chemical aspects.

The polymerization temperature is carried out at about 10 ~ 110 ℃, preferably about 50 ~ 90 ℃ when the polymerization is carried out in a slurry. The pressure used is about 1-50 kg / cm <2> * G, Preferably it is carried out on the conditions of 1-20 kg / cm <2> * G. The polymerization time is generally about 1 to 4 hours, preferably 2 hours for batch production, and corresponds to the average residence time for continuous processes. In the polymerization reaction of the present invention, the polymerization may be carried out in a batch, semi-continuous, or continuous manner, or may be carried out in two or more steps by changing the reaction conditions. In the present invention, a small amount of hydrogen is used as an additive to control the polymer molecular weight. Undesired catalyst poisons such as moisture, oxygen, carbon monoxide, carbon dioxide, acetylene, etc. must be removed in the reactor.

Hereinafter, the present invention will be described in more detail based on Examples, but the present invention is not limited to the Examples.

Example 1

a) Preparation of Polymerization Catalyst

A 1 L flask equipped with a stirrer was charged with 5.3 g (46.3 mmol) of magnesium ethoxide powder in 60 ml of toluene under a nitrogen atmosphere, followed by initial pretreatment with 0.8 ml (7.3 mmol) of tetrachlorotitanium. The mixture was heated to 90 ° C. over 20 minutes with stirring, followed by addition of 3.4 mL (16.2 mmol) of tetraethoxytitanium and 9.6 mL (91.8 mmol) of m-cresol. Then, the mixture was heated to 110 ° C. and reacted by stirring under nitrogen atmosphere for 1 hour.

The reaction product of the homogeneous solution thus obtained was cooled to room temperature, and 11.1 ml (91.5 mmol) of dimethylchlorosilane was added dropwise at room temperature over 1 hour, followed by stirring to obtain a slurry containing a white solid product. The obtained carrier component was analyzed using ICP (Ion Coupled Plasma) to find 0.62 wt% titanium and 14.5 wt% magnesium.

This solid product was isolated by filtration and washed three times with toluene. 50 ml of toluene was added to the solid product thus obtained, followed by stirring, and 25.3 ml (230 mmol) of tetrachlorotitanium was added thereto, and the temperature was raised to 92 ° C. Then, 2 ml (7.5 mmol) of dinormalyl phthalate was added dropwise and the temperature was raised to 110 ° C. After reacting for 2 hours. After the reaction was completed, the solid product was separated by filtration, toluene was added, the temperature was raised to 90 ° C., washed three times. Then, 60 ml of toluene was added thereto, and 25.3 ml (230 mmol) of tetrachlorotitanium was added and reacted at 110 ° C. for 2 hours. As a result, the solid catalyst component produced here was isolated by filtration and hexane was added, and the washing operation was thoroughly performed until the free titanium compound was no longer detected to obtain a solid catalyst component suspended in hexane. Analysis of the obtained catalyst constituents using ICP showed 1.46 wt% titanium and 17.3 wt% magnesium.

b) propylene polymerization

A 2 liter stainless autoclave equipped with a magnetic stirrer was sufficiently substituted with nitrogen and 900 ml of hexane was added thereto. Thereafter, a slurry containing 6 ml (5.26 mmol) of 15% by weight of triethylaluminum, 40 mg of cyclohexylmethyldimethoxysilane and 10 mg of the solid component obtained in a) was sequentially added as a catalyst component. After nitrogen was removed from the autoclave using a vacuum pump, 200 ml (8.9 mmol) of hydrogen was added, propylene was continuously added while stirring, the temperature was raised to 70 ° C., and the internal pressure of the autoclave was 10 kg / cm 2 · G. The polymerization was carried out for 2 hours by adjusting so as to occur.

After the completion of the polymerization, the mixture was cooled, and after removing the unreacted gas, the polypropylene was taken out, separated from the solvent by filtration, and dried.

The result was 350 g of polypropylene having a melt index of 8.3, an isotactic index of 99.2, and an apparent density of 0.36 g / cc, as shown in the accompanying Table 1. The activity of the solid catalyst component was 35000 g-PP / g-catalyst. Moreover, the average particle diameter was 230 micrometers, and the ratio of the microparticles whose particle diameter was 125 micrometers or less was 1.1 weight%. Figure 1 also shows the shape of the homogeneous polymer obtained via electron microscopy (SEM) for the polymer obtained using this method.

Example 2

330 g of polypropylene was obtained in the same manner as in Example 1 except that 5.1 ml (24.3 mmol) of tetraethoxytitanium was added to prepare a homogeneous solution.

Example 3

280 g of polypropylene was prepared in the same manner as in Example 1, except that 1.3 ml (11.6 mmol) of tetrachlorotitanium was added and 4.2 ml (20.8 mmol) of tetraethoxytitanium were added in the pretreatment reaction, the initial stage of the catalyst preparation process. Got.

Example 4

In the pretreatment reaction, the initial stage of the catalyst preparation process, 1.3 ml (11.6 mmol) of tetrachlorotitanium was added and 5.1 ml (24.3 mmol) of tetraethoxytitanium were added in the same manner as in Example 1 to obtain 360 g of polypropylene. Got.

Example 5

1.3 ml (11.6 mmol) of tetrachlorotitanium was added, 5.1 ml (24.3 mmol) of tetraethoxytitanium was added in the pretreatment reaction, an initial stage of the catalyst preparation process, and 5.6 ml (46.3 mmol) of dimethyldichlorosilane was added at room temperature. Except having dripped over 1 hour, it carried out similarly to Example 1, and obtained 310 g of polypropylenes.

Example 6

1.3 ml (11.6 mmol) of tetrachlorotitanium was added, 1.4 ml (6.9 mmol) of tetraethoxytitanium was added, and 7.2 ml (69.5 mmol) of m-cresol was added during the pretreatment reaction, the initial stage of the catalyst preparation process. A polypropylene 220g was obtained in the same manner as in Example 1 except for the above.

Example 7

In the pretreatment reaction, the initial stage of the catalyst preparation process, 2.9 mL (25.5 mmol) of tetrachlorotitanium was added, 5.1 mL (24.3 mmol) of tetraethoxytitanium was added, and 5.6 mL (46.3 mmol) of dimethyldichlorosilane was added at room temperature. Except having dripped over 1 hour, it carried out similarly to Example 1, and obtained 310 g of polypropylenes.

Comparative Example 1

230 g of polypropylenes were obtained in the same manner as in Example 1 except that 6.0 ml (30.1 mmol) of tetraethoxytitanium was added thereto.

Comparative Example 2

120 g of polypropylene was prepared in the same manner as in Example 1 except that 1.3 ml (11.6 mmol) of tetrachlorotitanium was added and 6.0 ml (30.1 mmol) of tetraethoxytitanium were added in the pretreatment reaction, which is an initial stage of the catalyst preparation process. Got.

Comparative Example 3

380 g of polypropylene was obtained in the same manner as in Example 1 except that m-cresol was not added to the active hydrogen organic compound. Figure 2 also shows the shape of the non-uniform polymer obtained via electron microscopy (SEM) for the polymer obtained using this method.

[Comparative Example 4]

150 g of polypropylene was obtained in the same manner as in Example 1 except that tetrachlorotitanium was not added in the pretreatment reaction, which is an initial stage of the catalyst preparation process.

[Comparative Example 5]

A polypropylene 350g was obtained in the same manner as in Example 1 except that tetraethoxytitanium was not added.

Comparative Example 6

170 g of polypropylenes were obtained in the same manner as in Example 1 except that dimethyldichlorosilane was not added.

Comparative Example 7

109 g of polypropylene was obtained in the same manner as in Example 1, except that 9.8 ml (16.2 mmol) of tetra 2-ethylhetocitanium was not added as an oxygen-containing organotitanium compound instead of tetraethoxytitanium.

Comparative Example 8

109 g of polypropylene was obtained in the same manner as in Example 1 except that 5.5 ml (16.2 mmol) of tetrabutoxy titanium was added instead of tetraethoxy titanium as the oxygen-containing organotitanium compound.

Experimental Example

The properties of the polymer produced in Examples 1 to 7 and Comparative Examples 1 to 8 were measured according to the following test method.

Catalyst activity: expressed as the amount of polymer produced per gram of polymerisation component.

Melt Flow Index (MFR): ASTM D-1238, Condition L. The total load is measured at 2.16 kg at 230 ° C. and recorded in g / 10 min.

Isotactic index (II): The ratio of insoluble polymer to the total polymer produced, expressed in weight percent after extraction with polymer n-heptane.

Apparent density (BD): g number of the apparent volume of a polymer of 1 cm <3>.

Average particle size: The value of the particle size corresponding to 50% of the weight integrated value of the polymer.

Particulate content: The proportion of the polymerization catalyst component having a particle size of less than 125 μm is expressed in weight%.

In the results of Table 1, in the slurry polymerization process, the average particle diameter of the polymer is too large (Comparative Examples 1 or 5), the particulate content is too high (Comparative Examples 6 or 8), or as shown in FIG. Catalysts with significantly poor particles (Comparative Example 3) are not applicable in the field, no matter how good the other physical properties of the polymer are.

First, the effect of the present invention is that the high polymerization activity of the catalyst does not require a deliming process to remove the residual catalyst, there is no smell and coloring of the polypropylene produced, and the polymerization process is simple, it is possible to save the process production cost.

The second effect is that the polypropylene produced after the polymerization has excellent powder properties. In other words, a polymer having a high apparent density, a spherical particle shape, a uniform and suitable average particle size, and extremely low microparticles can be obtained. Such particle characteristics may not only prevent the polymer from adhering to the inner wall of the polymerization reactor due to improved particle fluidity in the polymerization process, and to avoid depositing during transport, and also have a great advantage in selling powder products. In addition, the separation and transfer of the polymer in the slurry process and during the drying process can be facilitated. In particular, due to the spherical particle shape, the fluidity of the particles during the process is improved to improve the drying efficiency of the powder, eliminating the generation of bridges in the silo during the transfer process to eliminate the trouble. In addition, the scattering of fine particles is prevented and the fine powder is prevented from being mixed with atactic propylene. When the particles of the polymer are spherical and have a uniform particle size distribution, the product quality of the resin is also improved to obtain a propylene polymer having a certain level of quality.

The third effect is that the stereoregularity of the polymer is very good. Therefore, there is an effect of obtaining a polypropylene having better physical properties than before.

Claims (7)

In the production method of magnesium-supported polymerization catalyst used for the production of polyolefin, (i) mixing a transition metal compound (b) with an oxygen-containing magnesium compound (a) and performing partial pretreatment at 70 to 110 ° C; (ii) preparing a homogeneous solution by adding an oxygen-containing organic titanium compound (c) and an active hydrogen-containing organic compound (d) to the pretreatment reactant; (iii) adding a halogen-containing organosilane compound (e) to the homogeneous solution to form a precipitate, and recovering the precipitated spherical particulate carrier from the reaction solution; And (iv) treating the carrier with a transition metal compound (b) and an internal electron donor (f) to produce a solid polymerization catalyst. The oxygen-containing magnesium compound (a) according to claim 1, wherein the oxygen-containing magnesium compound (a) is a single compound or two or more selected from magnesium halides, alkoxy halides, halogenated aryloxy magnesiums, alkoxy magnesiums, aryloxy magnesiums, and carboxylic acid salts of magnesium. Method for producing a polyolefin polymerization catalyst, characterized in that the mixture. The method for preparing a polyolefin polymerization catalyst according to claim 1, wherein the transition metal compound (b) is a titanium halide. The polyolefin according to claim 1, wherein the oxygen-containing organotitanium compound (c) is a single compound or a mixture of two or more selected from alkoxytitanium trihalide, dialkoxytitanium dihalide, trialkoxytitanium halide and tetraalkoxytitanium. Method for producing a polymerization catalyst. The method for preparing a polyolefin polymerization catalyst according to claim 1, wherein the active hydrogen-containing organic compound (d) is phenol or m-cresol. The method of claim 1, wherein the organosilane compound (e) is selected from tetrachlorosilane, methyltrichlorosilane, dimethyldichlorosilane, diethyldichlorosilane, trichloromethoxysilane, dimethoxydichlorosilane, and trichloroethoxysilane. A method for producing a polyolefin polymerization catalyst, characterized in that more than one species. The method for preparing a polyolefin polymerization catalyst according to claim 1, wherein the internal electron donor compound (f) is di-n-alkylphthalate having 1 to 6 carbon atoms.

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