JPH0437083B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a method for producing polyolefins. More specifically, it relates to a method for producing a polyolefin that has high polymerization activity, produces very little low molecular weight by-products, and has excellent productivity by using a specific cocatalyst in a solid catalyst component containing magnesium and titanium. . Generally polymerization of ethylene and ethylene and other α
- When producing polyolefins by copolymerization with olefins, saturated or unsaturated hydrocarbon by-products with a molecular weight of + to several thousand are produced. On the other hand, the rise in raw material costs resulting from the recent petroleum situation is having a significant impact on the economic efficiency of polyolefin production. Therefore, if it is possible to reduce the production of low molecular weight by-products in the production of polyolefins, polyolefins can be produced with high productivity, resulting in great economic benefits. In addition, by reducing low molecular weight by-products in the polyolefin manufacturing process, there is less adhesion to reactor walls and clogging of piping, etc., making long-term continuous operation possible. Furthermore, it also gives favorable results to the physical properties of the product. In view of the above circumstances, the inventors of the present invention have made intensive studies and found that when polymerizing olefin using a catalyst system consisting of a transition metal compound component and an organoaluminium compound component, a solid catalyst component containing magnesium and titanium as the transition metal compound component is used. By using a specific oxygen-containing organoaluminum compound as the organoaluminum compound component, it has high polymerization activity, very little generation of low molecular weight by-products, excellent productivity, and the production process is also easy to use in the reactor. The present invention has been achieved by discovering a method for producing polyolefin that is free from adhesion and allows for long-term stable operation. That is, the gist of the present invention is that when polymerizing olefin using a catalyst system consisting of a transition metal compound component and an organoaluminium compound component, the transition metal compound component is selected from the following reaction products (A) to (C). Using a solid catalyst, (A) a reaction product of an oxygen-containing organic compound of magnesium, an oxygen-containing organic compound of titanium, and an aluminum halide compound (B) a reaction product of an oxygen-containing organic compound of magnesium, an oxygen-containing organic compound of titanium, and a silicon halide compound Reaction product (C) Reaction product between an oxygen-containing organic compound of magnesium and a titanium halogen compound As an organoaluminum compound component, the general formula A1R ¹ _1.5 (OR ² ) _0.5 X ¹ ... [1] (in the formula, R ¹ and R ² represent an alkyl group, and X ¹
represents a halogen atom. ) The present invention relates to a method for producing a polyolefin, characterized by using an oxygen-containing organoaluminum compound or composition shown in (a). To further explain the present invention in detail, in the present invention, a solid catalyst component containing magnesium and titanium as a transition metal compound component and an oxygen-containing organoaluminum compound or composition represented by the above general formula [] as an organoaluminum compound as a cocatalyst. By using the above-mentioned compound, low molecular weight by-products can be reduced and the object of the present invention can be achieved. In the general formula [], R ¹ and R ² are methyl, ethyl, propyl, butyl, pentyl, hexyl, octyl, phenyl, tolyl,
Examples include alkyl groups having up to about 15 carbon atoms such as cyclohexyl, and R ¹ and R ² may of course be different.
Examples of X ¹ include chlorine, bromine or iodine. Specifically, A1Et _1.5 (OEt) _0.5 C1, A1Et _1.5 (OBu)
_0.5 C1, A1Bu _1.5 (OBu) _0.5 C1, A1Oct _1.5 (O-Oct) _0.
5 C1 (Oct indicates octyl group), A1Et _1.5 (OEt) _0.5
Examples include Br. Among them, A1Et _1.5 (OEt) _0.5 C1
is particularly preferred. The method for producing such an oxygen- ^containing organoaluminum compound is not particularly limited, and methods well known to those skilled in the art may _be used. For example, ^{A1R 1} _2.0
A method of slowly dropping 0.25 mol of R ² OH per 1 mol of X 1 at room temperature, followed by heat treatment (about 60° ^C ), or A1R ¹ _2.0 X ¹ ₁ and A1R ¹ _1.0 (OR ² ) _1.0 X ¹
_A1R ¹ _1.5 (OR ^{2 )} _0.5 As the solid catalyst component containing magnesium and titanium, a reaction product selected from the following groups (A) to (C) is used. (A) Reaction product of an oxygen-containing organic compound of magnesium, an oxygen-containing organic compound of titanium, and an aluminum halide compound (B) A reaction product of an oxygen-containing organic compound of magnesium, an oxygen-containing organic compound of titanium, and a silicon halide compound (C) Reaction product of magnesium oxygen-containing organic compound and titanium halide compound (A) to (C) will be explained below. In the method of the present invention, the solid catalyst component is Known catalyst components such as, but not limited to, products obtained by treating magnesium dihalides with titanium halogen compounds after or during treatment with electron-donating compounds may also be used in the process of the invention. be able to. Method for producing the catalyst component of (A) The oxygen-containing organic compound of magnesium used in preparing the reaction product of (A) is Mg
(OR ³ )mX ² ₂ -m (wherein R ³ represents an alkyl group, aryl group or cycloalkyl group, X ² represents a halogen atom, and m is 1 or 2); Examples include magnesium diethoxide, magnesium dimethoxide, magnesium diphenoxide, magnesium monoethoxy chloride, magnesium monophenoxy chloride, magnesium monoethoxy bromide, magnesium monoethoxy iodide, and the like. Among these, magnesium diethoxide is preferred. _The oxygen-containing organic compound of titanium has the general formula Ti( ^OR4 ) ^{nX34
-n (} wherein, -butoxytitanium, diethoxydichlorotitanium, di-n-
Examples include butoxydichlorotitanium, triethoxymonochlortitanium, tri-n-butoxymonochlortitanium, ethoxytrichlortitanium, n-butoxytrichlortitanium, methoxytribromotitanium, and the like. Among these, tri-n-butoxymonochlorotitanium is preferred. As an aluminum halide compound, the general formula is
_Compounds ^{represented by} _A1R ^{5 P} Examples include ethylaluminum dichloride, ethylaluminum sesquichloride, diethylaluminum monochloride, normal propylaluminum dichloride, and the like. Among these, ethylaluminum sesquichloride is preferred. In the reaction of the above compounds, first, an oxygen-containing organic compound of magnesium and an oxygen-containing organic compound of titanium are mixed and heated to 100°C to 160°C to prepare a uniform liquid. When it is difficult to produce a uniform liquid, it is preferable to include alcohol. Examples of the alcohol include ethyl alcohol, n-butyl alcohol, and n-octyl alcohol. An inert hydrocarbon solvent is then added to form an inert hydrocarbon solution. An aluminum halogen compound is added to the inert hydrocarbon solution obtained as described above, and the mixture is heated to room temperature.
When the reaction is carried out at 100°C, the reaction product is obtained as a precipitate, and unreacted substances are washed away with an inert hydrocarbon solvent. The quantitative ratio of each component is the molar ratio of titanium compound to magnesium compound (Ti/Mg) of 0.1 to 10, and the ratio of the number of moles of aluminum halogen compound to the sum of the number of moles of magnesium compound and the number of moles of titanium compound [A1 compound ]/[Mg compound]+[Ti compound] is preferably 1 to 20. Method for producing the catalyst component of (B) The oxygen-containing organic compound of magnesium and the oxygen-containing organic compound of titanium used in preparing the reaction product of (B) may be those used in the preparation of (A). It is possible. As a silicon halogen compound, the general formula R ⁶
A silicon halogen compound represented by qSiX ⁵ ₄ -q (in the formula, R ⁶ represents an alkyl group, an aryl group, or a cycloalkyl group, and X ⁵ represents a halogen atom, and 0≦q≦2) is used. Ru. this house
Compounds in which X ⁵ is chlorine are preferred. Examples include silicon tetrachloride, methyltrichlorosilane, ethyltrichlorosilane, phenyltrichlorosilane, diethyldichlorosilane, etc., especially when q=0
The use of chlorinated silicon compounds, namely silicon tetrachloride, gives favorable results. In the reaction of these compounds, the reaction of the oxygen-containing organic compound of magnesium and the oxygen-containing organic compound of titanium is obtained in the same manner as the reaction in preparing the catalyst in (A). When a silicon halogen compound is added to the inert hydrocarbon solution obtained in this manner and reacted at room temperature to 100°C, the reaction product is obtained as a precipitate, and unreacted substances are washed away with an inert hydrocarbon solvent. Ru. The quantitative ratio of each component is the molar ratio of titanium compound to magnesium compound (Ti/Mg) of 0.1 to 10, and the ratio of the number of moles of silicon halogen compound to the sum of the number of moles of magnesium compound and the number of moles of titanium compound [Si compound ] / [Mg compound] + [Ti compound] 1 to 20
It is preferable that Method for producing catalyst component (C) The oxygen-containing organic compound of magnesium used in preparing the reaction product (C) can be the same as that used in (A). As a titanium halide compound, the general formula is TiX ⁶ ₁
(OR ⁷ ) ₄ −r (wherein, X ⁶ represents a halogen atom,
R ⁷ represents an alkyl group, an aryl group or a cycloalkyl group, and r is 1-4. Examples include titanium tetrahalides such as titanium tetrachloride, titanium tetrabromide, titanium tetraiodide, monoethoxytrichlorotitanium, monomethoxytribromotitanium, diethoxydichlorotitanium, and the like. Among these, titanium tetrahalide is preferred. The reaction between the oxygen-containing organic compound of magnesium and the titanium halide compound is carried out by contacting the two in the presence or absence of an inert hydrocarbon solvent at a temperature of 50°C to 200°C. The reaction product is obtained as a precipitate, and unreacted substances are washed away with an inert hydrocarbon solvent. There is no particular limit to the atomic ratio of titanium to magnesium in the reaction ratio between the two, but if it is too large, titanium will be wasted, and if it is too small, the polymerization activity will decrease. Therefore, usually Ti/Mg=0.1~
It is preferable to set it to 100 (molar ratio). The ratio of the solid catalyst component containing magnesium and titanium to the oxygen-containing organoaluminum compound is usually 0.1 to 100 in terms of Al/Ti atomic ratio, preferably 1 to 100.
Used within 20. The catalyst system thus prepared is used to polymerize olefins, and the olefins used in the method of the present invention include α-
One example is olefin. Moreover, these olefins can also be mixed and copolymerized. In particular, the process of the invention is advantageous for the production of ethylene homopolymers or copolymers of ethylene containing preferably up to 5 mol % of other α-olefins. The polymerization reaction can be carried out by solution polymerization or slurry polymerization carried out in an inert solvent or liquefied monomer, or by gas phase polymerization carried out in the absence of a solvent. This is usually carried out by supplying the olefin or olefin mixture and maintaining it at a predetermined temperature and pressure in the presence of an inert solvent. As the inert solvent, aliphatic hydrocarbons such as propane, butane, pentane, hexane, heptane, octane, and isooctane, and aromatic hydrocarbons such as benzene and toluene are used. The polymerization reaction is usually carried out at a temperature of from room temperature to 200°C and a pressure of from normal pressure to 100 atmospheres. Further, in the method of the present invention, when hydrogen is present in the polymerization reaction zone, the effect of controlling the molecular weight by hydrogen is large, and a polymerization zone having the desired molecular weight can be easily obtained. The amount of hydrogen to be present varies depending on the polymerization conditions, the desired molecular weight of the olefin polymer, etc., and therefore it is necessary to adjust the amount of hydrogen introduced accordingly. Further, the method of the present invention can be carried out in a method in which the polymerization reaction is carried out in one stage or in a multi-stage polymerization method in which two or more stages are carried out, but the effectiveness of the method of the present invention is particularly great in the case of a multi-stage polymerization system. That is, for example, in one of the first and second reaction zones, polymerization is performed in the presence of hydrogen at a molar ratio of 0.001 to 1.5 to ethylene in the gas phase, resulting in a polymer having a viscosity average molecular weight of 150,000 to 1,000,000. Polymer A is produced in an amount of 10% to 70% by weight of the total polymer production amount, and polymerized in the presence of hydrogen in a molar ratio of 1.5 to 15 to ethylene in the gas phase in the other zone to obtain a viscosity average molecular weight of 10,000. ~80,000 Polymer B is produced in 90% to 30% by weight of the total polymer production amount, and further (viscosity average molecular weight of polymer A) / viscosity average molecular weight of polymer B) is set to 4 to 80, The melt index of all the polymers finally produced is less than 0.5,
The method of the present invention is extremely effective in cases such as two-stage polymerization, especially when there is a large amount of hydrogen as a molecular weight regulator, such as in the production of Polymer B, since many low molecular weight by-products are produced. By using the cocatalyst according to the method of the present invention as described above when producing polyolefin, the amount of low molecular weight by-products produced is extremely small, resulting in excellent productivity, and also during the production process, there is no adhesion to the reactor. Various advantages can be obtained, such as no such problems, favorable long-term stable operation, and high polymerization activity. Next, the present invention will be explained in more detail with reference to examples, but the present invention is not limited to the following examples unless it exceeds the gist of the invention. It should be noted that FIG. 1 is a flowchart to help understand the technical content of the present invention, and the present invention is not limited in any way by this flowchart unless it deviates from the gist thereof. In the examples, the polymerization activity of the catalyst (hereinafter abbreviated as K)
is K=(g polymer)/(g・catalyst)(hr)
(Kg/cm ² olefin pressure). In addition, melt index (hereinafter abbreviated as MI)
is 2.16Kg at 190℃ based on ASTMD-1238-57T
Measured by load. Furthermore, the flow rate ratio (hereinafter abbreviated as FR), which is a measure of molecular weight distribution ^, is a value that indicates the dependence of melt viscosity on shear stress, and ^is based on ASTMD- ^1238-57T . It represents the outflow ratio of molten polymer in /cm ² , and it is said that the larger the FR, the wider the molecular weight distribution, and the smaller the FR, the narrower the molecular weight distribution. Further, the amount of low molecular weight by-products was measured by the method shown below. (1) Quantification of by-product grease wax (abbreviated as GW) After polymerization, take out a portion of the polymer slurry and
After distilling off the solvent, it was dried in a dryer at 80°C for 3 hours. The obtained polymer powder was extracted with refluxed normal hexane for 6 hours using a Soxhlet extractor. The soluble portion in refluxed normal hexane was defined as a by-product grease wax as follows. GW = weight of refluxed normal hexane soluble content / total polymer weight x 100 = weight% (2) Determination of by-product high boiler (abbreviated as HB) After the polymerization is completed, the polymer slurry is allowed to stand still, and the supernatant liquid is Take out a part and add 8 to 32 carbon atoms that are soluble in the polymerization solvent.
The saturated or unsaturated hydrocarbon components up to
It was measured using the method and determined as shown below. HB = sum of weights of saturated or unsaturated hydrocarbon components having 8 to 32 carbon atoms/total polymer weight x 100 = weight% Examples 1 to 3 115 g of magnesium diethoxide and tri-n-
151 g of butoxymonochlorotitanium and 37 g of n-butanol were mixed at 140° C. for 6 hours to homogenize.
Then, the temperature was lowered to 60°C, and benzene was added to form a homogeneous solution. Next, 454 g of ethylaluminum sesquichloride was added dropwise at 40°C, the temperature was raised to 60°C, and the mixture was stirred for 1 hour. A catalyst component was obtained by washing the generated precipitate with n-hexane. A part of the obtained solid slurry was dried and analyzed, and it was found that this solid contained 10.1% by weight of Mg.
It contained 10.0% by weight of Ti. Next, 1000 c.c. of normal hexane was placed in a second autoclave, and 10 mg of the above catalyst component was charged therein.
After raising the temperature to 90℃, a predetermined amount of hydrogen was introduced, and AlET _1.5
(OEt) _0.5 Cl 0.16 mmol was introduced together with ethylene,
The total pressure was 23 Kg/cm ² (gauge pressure). Ethylene absorption is seen with the introduction of ethylene, but when the total pressure is
Ethylene was additionally introduced to maintain the pressure at 23 kg/cm ² , and after 1 hour, the polymerization was stopped by injecting a small amount of ethanol. The results obtained are shown in Table 1. Comparative Example 1 AlEt _1.5 (OEt) _0.5 instead of C1 in Example 1
The procedure was exactly the same except that AlEt(OEt)C1 was used. The results obtained are shown in Table 1. Example 4 AlEt _1.5 (OEt) _0.5 instead of C1 in Example 1
AliBu _1.5 (O-iBu) _0.5 The same procedure was used except that C1 was used. The results obtained are shown in Table 1. Example 5 1000 c.c. of normal hexane in 2 autoclaves.
was charged with 25 mg of the catalyst component obtained in Example 1. After raising the temperature to 90° C., hydrogen was introduced to 18.3 Kg/cm ² , and 10.40 mmol of AlEt _1.5 (OEt) _0.5 C was introduced together with ethylene to bring the total pressure to 25 Kg/cm ² (gauge pressure). Absorption of ethylene was observed as ethylene was introduced, but ethylene was additionally introduced to maintain the total pressure at 25 Kg/cm ² , and the introduction of ethylene was stopped after 55 minutes.
During this time, 236 g of ethylene was absorbed. after that,
Purge the total pressure to 1.9Kg/cm ² (gauge pressure) and simultaneously cool to 80℃, then add 4.8g of 1-butene.
was introduced together with ethylene, and the total pressure was 4.0Kg/cm ²
(gauge pressure), the second stage polymerization was started. Additional ethylene was introduced in the same way as the first stage, and after 45 minutes
Polymerization was stopped by applying a small amount of ethanol pressure when 236 g of ethylene had been absorbed. The results obtained are shown below. First stage K = 1940 Hydrogen / ethylene (gas phase molar ratio) = 3.8 Second stage K = 4500 Hydrogen / ethylene (gas phase molar ratio) = 0.24 The obtained polymer is MI = 0.34 FR = 53 GW =
2.3% by weight HB=0.75% by weight. Example 6 57 g of magnesium diethoxide and 150 g of tri-n-butoxymonochlorotitanium were mixed at 130° C. for 6 hours and homogenized. Next, the temperature was lowered to 60°C, benzene was added to make a homogeneous solution, and 850g of silicon tetrachloride was added dropwise at 50°C.
The mixture was aged by stirring for hours. The generated precipitate was washed with normal hexane to obtain a catalyst component. Example 1 except that the catalyst component thus obtained was used.
Polymerization was carried out in exactly the same manner. The results obtained are shown in Table 2. Example 7 10g of magnesium diethoxide and titanium tetrachloride
70 ml was reacted at 130°C for 2 hours. After cooling n-
A catalyst component was obtained by washing with hexane. Polymerization was carried out in exactly the same manner as in Example 1 except for using the catalyst component thus obtained. The results obtained are shown in Table 2. Comparative Example 2 AlEt _1.5 (OEt) _0.5 instead of C1 in Example 1
The same procedure was carried out except that AlEt ₃ was used. The results obtained are shown in Table 3. Comparative Example 3 AlEt _1.5 (OEt) _0.5 instead of C1 in Example 1
The same procedure was performed except that AlEt ₂ Cl was used. The results obtained are shown in Table 3. Comparative Example 4 In Example 5, AlEt _1.5 (OEt) _0.5 was used instead of Cl.
Polymerization was carried out in exactly the same manner except that AlEt ₂ C1 was used. The results obtained are shown below. First stage K = 2050 Hydrogen / ethylene (gas phase molar ratio) = 3.8 Second stage K = 4830 Hydrogen / ethylene (gas phase molar ratio) = 0.24 The obtained polymer is MI = 0.31 FR = 56 GW =
3.3% by weight HB=1.3% by weight. Comparative Example 5 AlEt _1.5 (OEt) _0.5 instead of C1 in Example 6
The same procedure was carried out except that AlEt ₂ C1 was used. The results obtained are shown in Table 3. Comparative Example 6 The same procedure as in Example 7 was carried out except that AlEt ₂ Cl was used instead of AlEt _1.5 (OEt) _0.5 C1. The results obtained are shown in Table 3.

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【table】 [Brief explanation of drawings]

FIG. 1 is a flowchart showing one embodiment of the present invention.

Claims (1)

[Scope of Claims] 1. When polymerizing an olefin using a catalyst system consisting of a transition metal compound component and an organoaluminum compound component, the following transition metal compound components may be used.
Using a solid catalyst component selected from the reaction products of (A) to (C), the general formula
A1R ¹ _1.5 (OR ² ) _0.5 X ¹ (In the formula, R ¹ and R ² represent an alkyl group, and X ¹ represents a halogen atom.)
1. A method for producing a polyolefin, which comprises using an oxygen-containing organoaluminum compound or composition represented by: (A) Reaction product of an oxygen-containing organic compound of magnesium, an oxygen-containing organic compound of titanium, and an aluminum halide compound (B) A reaction product of an oxygen-containing organic compound of magnesium, an oxygen-containing organic compound of titanium, and a silicon halide compound (C) Reaction product 2 of magnesium oxygen-containing organic compound and titanium halogen compound The organic aluminum compound component is A1Et _1.5
(OEt) _0.5 The method according to claim 1, which is a compound or composition represented by C1.