JPH0542443B2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a method for producing an ethylene polymer,
Specifically, the present invention relates to a method for producing high-quality ethylene polymers using a catalyst that has high ethylene polymerization activity despite the use of a small amount of a transition metal compound. [Prior art and problems to be solved by the invention] Conventionally, a combination of a titanium catalyst component containing a magnesium compound such as magnesium chloride and an organoaluminium compound has been known as a catalyst with high ethylene polymerization activity. Polymerization of ethylene using such catalysts is widely practiced. However, in the conventional method described above, when preparing the catalyst, the amount of titanium compounds such as titanium tetrachloride used is larger than that of magnesium compounds. Another problem is that the disposal of surplus titanium compounds discharged after the polymerization reaction is expensive. In addition, in the conventional method, large amounts of highly halogenated titanium such as titanium tetrachloride are used, resulting in a high halogen content in the resulting polyethylene, resulting in problems such as deterioration of product quality and corrosion of molding equipment. It was hot. The present inventors have conducted extensive research in order to solve the problems of the above-mentioned conventional technology and to develop a method for producing high-quality ethylene polymers using a catalyst that has at least a high transition metal content and high activity. . [Means for solving the problem] As a result, it was discovered that the objective could be achieved by using a reaction product of a specific magnesium compound and a titanium compound as a transition metal-containing component that is a component of the catalyst. Ta. The present invention was completed based on this knowledge. That is, the present invention provides for the production of an ethylene polymer using a catalyst whose main components are (A) a transition metal-containing component and (B) an organoaluminum compound component.
As a transition metal-containing component, () at least one compound selected from the group consisting of magnesium alkoxides, magnesium fatty acid salts, and magnesium organic phosphorus-containing compounds ()
General formula Ti(OR ¹ ) _o (OCOR ² ) _4-o [In the formula, R ¹ and R ² each represent an alkyl group, a cycloalkyl group, or an aryl group having 1 to 20 carbon atoms, and n is 0≦n< 4
indicates a real number in the range of . ] Provides a method for producing an ethylene polymer, characterized by using a reaction product obtained by adding and reacting a titanium compound represented by 0.5 (molar ratio) or less. The catalyst used in the method of the present invention has the above-mentioned components (A) and (B) as main components, and the transition metal-containing component that is the (A) component is a compound of the above-mentioned () and (). is the reaction product of Here, the magnesium alkoxide of the compound () includes magnesium dimethoxide, magnesium diethoxide, magnesium dipropoxide, magnesium dibutoxide, magnesium diheptoxide, magnesium dioctoxide, magnesium distearoxide, etc. Examples include dialkoxides. Among these, those containing long-chain alkyl groups are preferred because they become microgen or soluble in hydrocarbon solvents such as hexane, heptane, toluene, etc. and have high activity. Especially carbon number 6-20
Those having a hydrocarbon group of Moreover, there are various kinds of fatty acid salts of magnesium, and various kinds can be used. Specific examples of fatty acids constituting this fatty acid salt include monocarboxylic acids such as acetic acid, propionic acid, caproic acid, undecylic acid, lauric acid, palmitic acid, and stearic acid; dicarboxylic acids such as succinic acid and adipic acid; acid, ketocarboxylic acids such as levulinic acid, or unsaturated carboxylic acids such as linoleic acid and linolenic acid. Among these, those containing a long-chain alkyl group having 6 to 20 carbon atoms are preferred because they become microgels or soluble systems in hydrocarbon solvents such as hexane, heptane, toluene, etc., and have high activity. Furthermore, there are various organic phosphorus-containing compounds for magnesium, and although there are no particular restrictions,
Preferably, it is obtained by reacting an organomagnesium compound and a hydrogen-containing phosphorus compound. Here, the organomagnesium compound has the general formula R ³ R ⁴ Mg
[In the formula, R ³ and R ⁴ each represent an alkyl group or an aryl group having 1 to 10 carbon atoms. ] or a compound represented by the general formula R ³ MgX [wherein, X represents a halogen atom, and R ³ is the same as above. ] Compounds represented by the following are preferred. Specifically, organic magnesium compounds such as ethylbutylmagnesium, dibutylmagnesium, diethylmagnesium, dihexylmagnesium, and ethylmagnesium chloride can be mentioned. On the other hand, hydrogen-containing phosphorus compounds include alkyl or arylphosphines such as methylphosphine, ethylphosphine, propylphosphine, butylphosphine, and phenylphosphine, diethylphosphine, dipropylphosphine, and dibutylphosphine. , dialkyl or diarylphosphines such as diphenylphosphine, alkyl or arylphosphonic acids such as ethylphosphonic acid, propylphosphonic acid, diethylphosphinic acid, dipropylphosphinic acid, dibutylphosphinic acid, didodecylphosphinic acid , dialkyl or diarylphosphinic acids such as diphenylphosphinic acid, methyl phosphite, butyl phosphite, dimethyl phosphite, dipropyl phosphite, dibutyl phosphite, dodecyl phosphite Phosphite esters such as ester, dilauryl phosphite, dioleyl phosphite, diphenyl phosphite, ethyl phosphate, propyl phosphate, dipropyl phosphate, dibutyl phosphate , phosphoric acid esters such as phosphoric acid dioctyl ester and phosphoric acid dodecyl ester. Among them, those containing a long-chain alkyl group having 6 to 20 carbon atoms are preferred because they become microgels or soluble systems in hydrocarbon solvents such as hexane, heptane, and toluene, and have high activity. Specific examples of the compound () to be reacted with the compound () above, that is, the titanium compound represented by the general formula Ti(OR ¹ ) _o (OCOR ² ) _4-o , include titanium monoethoxy triacetate, titanium monoethoxy Tributyrate, titanium monoisopropoxy tributyrate, titanium monoisopropoxy trilaurate, titanium monoisopropoxy tristearate, titanium monobutoxy tristearate, titanium diethoxy diacetate, titanium diisopropoxy dilaurate, titanium diiso Propoxy distearate, titanium dibutoxy distearate,
Examples include titanium triethoxy monobutyrate, titanium triisopropoxy monolaurate, titanium triisopropoxy monostearate, titanium tetraacetate, titanium tetrabutyrate, titanium tetralaurate, and titanium tetrastearate. Component (A) of the catalyst used in the method of the present invention is a reaction product of the above-mentioned compound () and the compound (). When reacting the magnesium compound () with the titanium compound (), the reaction conditions are not particularly limited and may be determined as appropriate depending on various situations. Preferably, these (),
The titanium atom in the reaction product of the compound () is 0.5 to the magnesium atom (i.e., Ti/Mg).
(molar ratio) or less, preferably 0.005 to 0.4 (molar ratio)
Both compounds () and () are used so that If the content of titanium atoms in the reaction product is too large, the amount of titanium consumed during ethylene polymerization will increase, and it will be necessary to wash and remove surplus titanium compounds and waste titanium compounds, making it economically and industrially difficult. I also don't like it. Moreover, even if the titanium atom content increases to the extent that it exceeds the above-mentioned ratio, it hardly contributes to improving the activity of the resulting catalyst. This reaction is usually carried out in an inert hydrocarbon solvent such as pentane, hexane, or heptane at a temperature of 0 to 200°C.
Preferably 30 to 150°C, reaction time 5 minutes to 10 hours,
Preferably, the heating time is 30 minutes to 5 hours. In addition, when reacting the above magnesium () with the titanium compound (), an electron-donating compound is added and reacted as needed to obtain a reaction product, and this reaction product is used as an ethylene polymerization catalyst. It can also be used as component (A) (transition metal-containing component). According to the method of the present invention, the above reaction product is converted into (A)
component, and the organoaluminum compound component (B)
Ethylene is polymerized using a catalyst mainly composed of two components (A) and (B) to produce an ethylene polymer. There are various organoaluminum compounds, but halogen-containing alkylaluminum compounds are preferred, and specific examples include diethylaluminum monochloride, diisopropylaluminum monochloride, diisobutylaluminum monochloride,
Dialkylaluminum monohalides such as dioctylaluminum monochloride, monoalkylaluminum dihalides such as ethylaluminum dichloride, isopropylaluminum dichloride, isobutylaluminum dichloride, alkylaluminum sesquihalides such as methylaluminum sesquichloride, ethylaluminum sesquichloride, ethylaluminum sesquibromide, etc. Suitable examples include mixtures thereof, and mixtures thereof with trialkylaluminum compounds such as triethylaluminum, triisopropylaluminum, triisobutylaluminum, and trioctylaluminum. When polymerizing ethylene by the method of the present invention, the above-mentioned (), which is component (A), is added to the reaction system.
The reaction product of the compound () and the organic aluminum compound as the component (B) are added, and then the raw material ethylene is introduced into the system. The polymerization method and conditions are not particularly limited, and any of solution polymerization, suspension polymerization, gas phase polymerization, etc. is possible, and both continuous polymerization and discontinuous polymerization are possible. For example, in the case of solution polymerization or suspension polymerization, the amount of the catalyst component added is 0.001 to 5.0 mmol/, preferably 0.002 to 1.0 mmol/in terms of titanium atoms of component (A), and (B) The amount of the component is 1 to 5,000 (molar ratio), preferably 5 to 1,000 (molar ratio) to the titanium atoms in component (A). The pressure of the reaction system is preferably normal pressure to 50Kg/ ^cm2 , and the reaction temperature is 0.
~300°C, preferably 50-250°C. Molecular weight adjustment during polymerization can be carried out by known means, such as hydrogen. The reaction time is 5 minutes ~
The time period may be appropriately selected from 10 hours, preferably from 30 minutes to 5 hours. In the method of the present invention, polyethylene is usually produced by polymerizing ethylene, but ethylene-based copolymers can also be produced by copolymerizing ethylene with other α-olefins. The α-olefins that can be used in this case include linear monoolefins such as propylene, butene-1, hexene-1, octene-1, and 4-methyl-pentene-1.
Examples include branched monoolefins such as [Effects of the Invention] According to the method of the present invention, the amount of titanium compounds consumed during the preparation of the catalyst used is small, and almost all of the titanium compounds used are utilized as catalysts, so that waste titanium compound processing equipment can be used. does not require. Furthermore, since the catalytic activity is very high, a deashing step (catalyst removal step) is not necessary, and as a result, the ethylene polymer can be produced extremely efficiently. Moreover, since the magnesium salt in the catalyst also acts as a lubricant, the dispersibility of the catalyst in the ethylene polymer during the polymerization stage is improved, and as a result, a homogeneous ethylene polymer is obtained. Furthermore, this ethylene polymer has a low halogen content and is of very high quality, and there is no fear of corroding the extruder used for molding this ethylene polymer. [Example] Next, the present invention will be explained in more detail with reference to Examples. Example 1 (1) Preparation of titanium-containing component In a 200 ml flask purged with argon, 40 ml of dehydrated n-heptane, 4.0 g (6.8 mmol) of magnesium stearate, and 0.68 g (0.68 mmol) of titanium monoisopropoxy tristearate were added. was added, heated, and reacted under reflux for 3 hours.
The entire amount of the reactant was obtained as a titanium-containing component (reaction product). (2) Polymerization of ethylene In an argon-substituted autoclave with an internal volume of 1, 400 ml of dehydrated n-hexane, 2 mmol of triethylaluminum, 2 mmol of diethylaluminum chloride, and the titanium-containing component obtained in (1) above were added in an amount of 0.01 mmol as titanium atoms. and 80
The temperature was raised to .degree. C., and hydrogen was supplied so that the hydrogen partial pressure was 3 Kg/ ^cm.sup.2 . Next, ethylene was continuously supplied so that the partial pressure of ethylene was 5 kg/cm ² , and the polymerization reaction was carried out for 1 hour to obtain 23.7 g of polyethylene. The results are shown in the table. Example 2 (1) Preparation of titanium-containing components In a 200 ml flask purged with argon, 40 ml of dehydrated n-heptane, 4.0 g (6.8 mmol) of magnesium stearate, and 0.65 g (0.68 mmol) of titanium monoisopropoxy tristearate were added. was added, heated, and reacted under reflux for 3 hours.
The entire amount of the reactant was obtained as a titanium-containing component (reaction product). (2) Polymerization of ethylene Into an argon-substituted autoclave with an internal volume of 1, 400 ml of dehydrated n-hexane, 2 mmol of diethylaluminum chloride, and 0.01 mmol of the titanium-containing component obtained in (1) above as titanium atoms were placed at 80°C. The temperature was raised to , and hydrogen was supplied so that the hydrogen partial pressure was 3 Kg/cm ² . Next, ethylene was continuously supplied so that the partial pressure of ethylene was 5 kg/cm ^{2 ,} and the polymerization reaction was carried out for 1 hour to obtain 61.2 g of polyethylene. The results are shown in the table. Example 3 (1) Preparation of titanium-containing component 50 ml of dehydrated n-heptane and 6.45 g (20 mmol) of di-2-ethylhexyl phosphate were placed in a 200 ml flask purged with argon.
30 ml of a heptane solution of ethylbutylmagnesium (10 mmol) was added dropwise at room temperature over 20 minutes. After the dropwise addition was completed, the temperature was raised and the reaction was allowed to proceed for 3 hours under refluxing n-heptane. The temperature was lowered to 40℃, and 0.96 g (1 mmol) of titanium monoisopropoxy tristearate was added.
The temperature was raised again and the mixture was reacted for 3 hours under reflux of n-heptane to obtain the entire amount of the reaction product as a titanium-containing component. (2) Polymerization of ethylene In an argon-substituted autoclave with an internal volume of 1, 400 ml of dehydrated n-hexane, 2 mmol of toluethylaluminum, 2 mmol of diethylaluminum chloride, and the titanium-containing component obtained in (1) above were added to a 0.01 titanium atom. Put mmol, 80
The temperature was raised to .degree. C., and hydrogen was supplied so that the hydrogen partial pressure was 3 Kg/ ^cm.sup.2 . Next, ethylene was continuously supplied so that the partial pressure of ethylene was 5 kg/cm ² and the polymerization reaction was carried out for 1 hour to obtain 53.6 g of polyethylene. The results are shown in the table. Example 4 (1) Preparation of titanium-containing component 4.0 g of magnesium stearate of Example 1 (1)
A titanium-containing component was obtained in the same manner except that 0.78 g (6.8 mmol) of magnesium diethoxide was used instead of (6.8 mmol). (2) Polymerization of ethylene Polyethylene was obtained by polymerizing ethylene in the same manner as described in (2) of Example 1, except that the titanium-containing component obtained in (1) above was used. The results are shown in the table. Example 5 (1) Preparation of titanium-containing component Except that 0.8 g (0.68 mmol) of titanium tetrastearate was used instead of 0.65 g (0.68 mmol) of titanium monoisopropoxy tristearate in Example 2 (1). A titanium-containing component was obtained in the same manner. (2) Polymerization of ethylene Polyethylene was obtained by polymerizing ethylene in the same manner as described in (2) of Example 2, except that the titanium-containing component obtained in (1) above was used. The results are shown in the table. Comparative Example 1 400 ml of dehydrated n-hexane, 2 mmol of triethylaluminum, 2 mmol of diethylaluminum chloride, and 0.01 mmol of titanium monoisopropoxy tristearate as titanium atoms were placed in an argon-substituted autoclave with an internal volume of 1, and the temperature was raised to 80°C. Heat to a hydrogen partial pressure of 3Kg/cm ²
Hydrogen was supplied so that Next, ethylene was continuously supplied and the polymerization reaction was carried out for 1 hour to obtain 0.2 g of polyethylene. The results are shown in the table. Comparative Example 2 (1) Preparation of titanium-containing component In a 200 ml flask purged with argon, 40 ml of dehydrated n-heptane, 4.0 g (6.8 mmol) of magnesium stearate, and 6.5 g (6.8 mmol) of titanium monoisopropoxy tristearate were added.
was added, the temperature was raised, and the reaction was carried out under reflux for 3 hours to obtain the entire amount of the reaction product as a titanium-containing component (reaction product). (2) Polymerization of ethylene In an argon-substituted autoclave with an internal volume of 1, 400 ml of dehydrated n-hexane, 2 mmol of toluethylaluminum, 2 mmol of diethylaluminum chloride, and the titanium-containing component obtained in (1) above were added to a 0.01 titanium atom. Put mmol, 80
The temperature was raised to .degree. C., and hydrogen was supplied so that the hydrogen partial pressure was 3 Kg/ ^cm.sup.2 . Next, ethylene was continuously supplied so that the partial pressure of ethylene was 5 kg/cm ² , and the polymerization reaction was carried out for 1 hour to obtain 2.3 g of polyethylene. The results are shown in the table. 【table】

[Brief explanation of drawings]

FIG. 1 is a drawing showing the preparation process of a catalyst used in the method of the present invention.

Claims (1)

[Claims] 1. In producing an ethylene polymer using a catalyst whose main components are (A) a transition metal-containing component and (B) an organoaluminum compound component, (A) a transition metal-containing component ( ) General formula Ti (OR ¹ ) _o (OCOR ² ) _4-o [Formula In the formula, R ¹ and R ² each represent an alkyl group, a cycloalkyl group, or an aryl group having 1 to 20 carbon atoms, and n represents a real number in the range of 0≦n<4. ] A titanium compound represented by
A method for producing an ethylene polymer, characterized by using a reaction product obtained by adding and reacting at a ratio of 0.5 (molar ratio) or less. 2. The method according to claim 1, wherein the magnesium compound has a hydrocarbon group having 6 or more carbon atoms.