JPH0662705B2 - Method for producing polyethylene - Google Patents

Description

TECHNICAL FIELD The present invention relates to a method for producing polyethylene with a novel catalyst. More specifically, it is characterized by polymerizing ethylene or copolymerizing ethylene and α-olefin using a novel catalyst which is highly active and can obtain high molecular weight polyethylene under the temperature conditions above the melting point of polyethylene. It relates to a manufacturing method.

Generally, ethylene polymers and ethylene-α-olefin copolymers polymerized by Ziegler type catalysts have a wide density of usually 0.890 to 0.975 g / cm ³ ,
It is used in a wide range of applications such as films and molded products.

[Conventional technology]

As a method for polymerizing ethylene at a temperature above the melting point of polyethylene using a Ziegler type catalyst, a solution polymerization method and a high temperature and high pressure polymerization method are known. Generally, in a solution polymerization method carried out in an inert solvent, a higher polymerization temperature is preferable in view of reduction of solution viscosity and easy removal of heat of polymerization. Similarly, in the high-temperature and high-pressure method, the larger the temperature difference between the polymerization temperature and the feedstock, the higher the ethylene conversion rate. On the other hand, in the polymerization in these high temperature regions, generally, by raising the polymerization temperature, the catalytic activity and the activity sustainability are lowered, and it becomes difficult to produce high molecular weight polyethylene. If the catalyst activity is low, the amount of catalyst residue in the polymer increases, which is likely to cause corrosion of process equipment, polymer coloring, and gel formation. Many proposals have been made as catalysts that can be used for high temperature polymerization. For example, a catalyst system combining a titanium compound, a vanadium compound and a trialkylaluminum compound was proposed in US Pat. No. 3,218,266. However, although high molecular weight polyethylene can be obtained with this catalyst system, it is necessary to remove the catalyst residue from the produced polyethylene due to its low catalytic activity. In Japanese Patent Publication No. 46-15109, a catalyst system comprising a π-allyl compound of a transition metal of IVA to VIA of the periodic table in the high temperature and high pressure method is proposed. Since this catalyst system does not contain corrosive ligands, it does not corrode process equipment or processing equipment, but has low catalyst activity and does not include a catalyst removal step, which causes problems such as polymer coloring and gel formation. Further, in the copolymerization of ethylene and α-olefin, the usual Ziegler type catalyst has a high ethylene polymerizability, but the polymerizability of the α-olefin having 4 or more carbon atoms is extremely low. Therefore, a copolymer having a desired α-olefin content. It is necessary to supply a higher concentration of α-olefin to the reactor than is considered necessary to obtain the above, which is economically disadvantageous.

[Problems to be solved by the invention]

It is an object of the present invention to provide a catalyst component capable of obtaining a highly active and high molecular weight polyethylene which does not require a catalyst removal step in a temperature range higher than the melting point of polyethylene. Another object of the present invention is to use α-olefin in the copolymerization of ethylene and α-olefin using this catalyst component.
It is to relatively improve the reactivity of olefins.

[Means for solving problems]

The gist of the present invention is [1] [A] (1) titanium trichloride or a composite component of titanium trichloride and magnesium chloride, (2) vanadium trichloride, and (3) general formula B (OR ¹ ) _m X ¹ _3-m · Y _n
(Here, R ¹ represents a hydrocarbon group having 1 to 20 carbon atoms, X ¹ represents a halogen atom, Y represents an ether or halogenophosphine oxide, m is 0 ≦ m ≦ 3, and n is 0 or 1. In the presence of a catalyst system consisting of a solid catalyst component obtained by co-milling a boron compound represented by the formula (4) and [B] an organoaluminum compound, ethylene is polymerized at a temperature not lower than the melting point of polyethylene or ethylene and at least one α -Process for producing polyethylene characterized by copolymerizing olefin, and [2] [A] (1) Titanium trichloride or a composite component of titanium trichloride and magnesium chloride
(2) Vanadium trichloride (3) General formula B (OR ¹ ) _m X ¹
_3-m · Y _n (wherein R ¹ is a hydrocarbon group having 1 to 20 carbon atoms, X ¹ is a halogen atom, Y is an ether or a halogenophosphine oxide, m is 0 ≦ m ≦ 3, and n is 0
Or it is a number of one. ) A boron compound represented by
(4) General formula _{^{R 2 p Si (OR 3)}} q X 2 4-p-q ( wherein ^R 2, ^{R 3} is a hydrocarbon group or a hydrogen atom having 1 to 20 carbon atoms, ^{X 2} represents a halogen atom , P is 0 ≦ p ≦
4, q has a relationship of 0 ≦ q ≦ 4, 0 ≦ p + q ≦ 4. In the presence of a catalyst system consisting of a solid catalyst component obtained by co-milling a silicon compound represented by the formula (4) and [B] an organoaluminum compound, ethylene is polymerized at a temperature not lower than the melting point of polyethylene or ethylene and at least one α −
A method for producing polyethylene is characterized by copolymerizing an olefin.

The details will be described below.

1) Catalyst used Titanium trichloride as the component [A] (1) in the present invention is one obtained by reducing titanium tetrachloride with hydrogen or aluminum, or one reduced with an organic aluminum compound such as diethylaluminum chloride. 1/3 mol AlCl ₃
It is possible to use the one with added. Further, depending on the type of boron compound, the catalytic activity can be increased by adding magnesium chloride, so magnesium chloride can be added as necessary. The general formula B (OR ¹ ) _m X ¹ _3-m · Y _{n of the} component [A] (3) (wherein R ¹ is a hydrocarbon group having 1 to 20 carbon atoms, preferably 1 to 8 carbon atoms, and X ¹ is halogen) Atom, Y
Represents ether or halogenophosphine oxide, m is 0 ≦ m ≦ 3, and n is a number of 0 or 1. Examples of the boron compound represented by) include trimethyloxyboron, triethoxyboron, tri-i-propoxyboron, and tri-i.
-Butoxyborone, tri-t-butoxyborone, tri-n-
Butoxyboron, tri-n-pentoxyborone, ethoxydi-n-butoxyborone, diethoxyboron chloride, diethoxyboron bromide, ethoxyboron dichloride,
Ethoxyboron dibromide, boron trichloride, boron tribromide, boron trifluoride diethyl ether adduct, boron trichloride oxytrichloride trichloride adduct and the like, but especially triethoxyboron, tri i-propoxyboron, trichloride Boron, boron tribromide, boron trifluoride diethyl ether adduct and boron trichloride oxytrichloride trichloride adduct are preferable. These boron compounds may be used alone or in combination of two or more. Further, the general formula of [A] (4), which can be added if necessary,
R ² _p Si (OR ³ ) _q X ² _4-pq (wherein R ² and R ³ may be the same or different and have 1 to 20 carbon atoms, preferably 1 to 10 hydrocarbon groups or hydrogen atoms, X ² represents a halogen atom, p
0 ≦ p ≦ 4 and q have a relationship of 0 ≦ q ≦ 4 and 0 ≦ p + q ≦ 4. ), Silicon tetrachloride, trichlorosilane, dichlorodihydrosilane,
Chlortrihydrosilane, methyltrichlorosilane, dimethyldichlorosilane, trimethylchlorosilane, triethylchlorosilane, diethyldichlorosilane, tri-n
-Propylchlorosilane, tri-n-butylchlorosilane, di-n-butyldichlorosilane, triphenylchlorosilane, diphenyldichlorosilane, methylethyldichlorosilane, tetramethoxysilane, tetraethoxysilane, methyltrimethoxysilane, ethoxy Examples thereof include trimethylsilane, diethoxymethylhydrosilane, trimethoxyethylsilane, diphenyldiethoxysilane, diphenylsilanediol and the like, with silicon tetrachloride, trichlorosilane, tetraethoxysilane and diphenylsilanediol being particularly preferred. Next, the organoaluminum compound of the component [B] used as the cocatalyst component is represented by the general formula R ⁴ _S AlX ³ _3-S (wherein R ⁴ has 1 to 10 carbon atoms,
Preferably, 2 to 8 hydrocarbon groups, X ³ represents a halogen atom, and s has a relationship of 0 <s ≦ 3. ). Specific examples of such an organoaluminum compound include triethylaluminum, tri-n-propylaluminum, triisobutylaluminum, tri-n-butylaluminum, tri-n-hexylaluminum, tri-n-octylaluminum, diethylaluminum chloride, di-n-propyl. Examples thereof include aluminum chloride, diisobutylaluminum chloride, ethylaluminum sesquichloride, isobutylaluminum sesquichloride and the like, and triethylaluminum, triisobutylaluminum, tri-n-octylaluminum and the like are particularly preferable.

2) Amount ratio Solid catalyst component [A] is component (1), component (2) and component (3)
Furthermore, it is a contact product with the component (4). The amount of each component used is arbitrary as long as the effects of the present invention are recognized, but generally the following ranges are preferred. The amount of vanadium trichloride used as component (2) is in the range of 0.05 to 20 mol, preferably 0.2 to 5 mol, per mol of the titanium compound of component (1). Even if the molar ratio of both exceeds 20, it is still 0.05
If it is less than the above range, the catalytic activity is remarkably reduced, and problems such as coloring of the produced polymer and gel formation occur. The amount of the boron compound used is 0. 1 mol of the transition metal compound (component (1) + component (2)).
The amount is 001 to 10 mol, preferably 0.02 to 1 mol. If the amount of the boron compound used is too large or too small, the desired catalytic activity cannot be obtained.
Component (1) is sufficiently effective when used alone as titanium trichloride, but can also be used as a complex component with magnesium chloride. If magnesium chloride is also used, its amount is preferably 20 mol or less per 1 mol of titanium trichloride. When the silicon compound of the component (4) is further added, the amount of the silicon compound used is a transition metal compound (component
The amount is 10 mol or less, preferably 1 mol or less, relative to 1 mol of (1) + component (2)). The addition of the silicon compound brings about the effect of increasing the molecular weight. The amount of the organoaluminum compound (component [B]) used as a cocatalyst is not particularly limited, but is usually 1 to 1000 mol, particularly 1 mol per 1 mol of the transition metal compound (component (1) + component (2)). It is preferably in the range of up to 100 mol.

3) Method for preparing catalyst The co-milling of the components [A] (1), (2) and (3) in the present invention may be carried out by coexisting three components at the same time, or any two components may be first co-milled, There is no problem even if the other component is added and crushed. In addition, the component [A] (4)
Similarly, when the silicon compound is coexistent, the addition method is not limited at all. Of course, these operations should be carried out in an inert gas atmosphere and without moisture. The crusher used is not particularly limited, but a ball mill, a vibration mill, an impact mill or the like is usually used. Further, the optimum conditions for performing mechanical crushing treatment with a ball mill or the like vary depending on the type and filling rate of balls, the rotation speed, the crushing temperature, the crushing time, etc. Can be easily determined. Further, the solid catalyst component [A] is dispersed in a hydrocarbon solvent and injected into the reaction apparatus. Therefore, the smaller the powder diameter, the more preferable. Therefore, if desired, the solid catalyst component [A] can be finely divided by known prepolymerization without any problem.

4) Polymerization The polymerization of the present invention is homopolymerization of ethylene or copolymerization of ethylene with at least one other α-olefin. The α-olefin used for copolymerization with ethylene is preferably one having 4 to 12 carbon atoms, and specific examples include 1-butene, 1-hexene, 4-methyl 1-pentene, 1-octene, 1-decene and the like. And mixtures thereof are used. Although the amount of the α-olefin used varies depending on the polymerization conditions, the density of the desired copolymer, etc., it is generally 5 mol or less of the α-olefin relative to 1 mol of ethylene. The polymerization reaction of ethylene is carried out at a temperature not lower than the melting point of the produced polymer, preferably 130 to 300 ° C, and an inert solvent or the monomer itself is used as the polymerization medium. In solution polymerization using an inert solvent, aliphatic hydrocarbons such as hexane, heptane, octane, nonane, decane, undecane, dodecane and mixtures thereof, aromatic hydrocarbons such as benzene and toluene, cyclohexane, methyl are used as polymerization solvents. Alicyclic hydrocarbons such as cyclohexane are used, and the polymerization pressure is 1 to 20.
0 kg / cm ^2, preferably at the range of 10 to 50 kg / cm ^2. Further, in the high temperature and high pressure polymerization in which the monomer itself is used as a polymerization medium, a high pressure radical polymerization apparatus of ethylene or the like can be generally used, and the polymerization pressure is 200 to 2500 kg / cm ² ,
It is preferably carried out in the range of 400 to 1500 kg / cm ² .
In the present invention, the molecular weight of the polymer is achieved by adjusting the reaction temperature, but it can be easily adjusted by allowing hydrogen to be present in the polymerization reaction zone. Since the amount of hydrogen varies depending on the polymerization conditions, the desired molecular weight of the ethylene polymer, etc., it is necessary to adjust the amount appropriately.

〔The invention's effect〕

The effects of the present invention are as listed below, and industrially great profits can be obtained. That is, 1) Since the polymerization activity per transition metal and solid catalyst is high even at high temperature, a catalyst removing step is not required.

2) High molecular weight polyethylene can be obtained even at relatively high temperatures.

3) Since the copolymerizability is good, it is possible to produce a low density copolymer with a low comonomer concentration.

〔Example〕

Examples of the present invention are shown below, but the present invention is not limited to these examples as long as the gist thereof is not exceeded.

In the examples, MI represents melt index, and JIS
It is measured under the conditions of a temperature of 190 ° C. and a load of 2.16 kg based on K-6760. Density is JIS K-67
It measured according to 60. The catalyst activity is the amount of polymer produced per gram of solid catalyst (kg) and the transition metal (Ti
+ V) The amount of polymer produced per 1 g was expressed in kg.

Example 1 (a) Preparation of catalyst Titanium trichloride (TiCl ₃₎ obtained by reducing titanium tetrachloride with metallic aluminum into a stainless steel pot with an internal volume of 420 m containing 1.2 kg of stainless steel balls with a diameter of 4 mm
・ 1 / 3AlCl ₃ ) 80 g, vanadium trichloride 6.3 g and triethoxyboron 1.2 g are sealed in a nitrogen atmosphere,
Co-milled for 12 hours with a vibrating mill. 1.0 g of the solid powder obtained after pulverization was used as a solvent (IP-1620, manufactured by Idemitsu Petrochemical Co., Ltd.) 10 containing isoparaffin having 10 to 11 carbon atoms as a main component.
The catalyst slurry was dispersed by 0 m to prepare a catalyst slurry.

(b) Polymerization A stainless steel autoclave with an internal volume of 2 and an induction stirrer was replaced with nitrogen, and IP-1620 1000 m and 1
-Butene (40 m) was added and the temperature was raised to 180 ° C with stirring. The system becomes 2.6 kg / cm ² G due to the vapor pressure of the solvent and 1-butene, but ethylene was added until the total pressure reached 22.6 kg / cm ² G, and the catalyst slurry prepared in advance of 0.
A mixture of 96 m (9.6 mg as a solid catalyst) and 0.20 mmol of triethylaluminum was added to initiate polymerization. When ethylene was continuously introduced and polymerization was carried out for 20 minutes while keeping the total pressure constant, 208 g of a polymer was obtained. The catalytic activity is 21.7 kg / g solid, 84.7 kg / g (Ti +
V), MI was 0.17 and density was 0.920.

Examples 2-5 All Example 1 except that the boron compound of Table 1 was used in place of triethoxyboron in the catalyst preparation of Example 1.
A catalyst was prepared and polymerized in the same manner as in. The results are
Shown in 1.

Comparative Examples 1 to 3 To clarify the effect of the present invention, TiCl ₃ .1 / 3AlCl ₃ and VC
l ₃ ,, TiCl ₃・ 1 / 3AlCl ₃ and B (OC ₂ H ₅ ) ₃ and VCl ₃ and B (OC ₂ H ₅ ) ₃
Were pulverized, and the same polymerization as in Example 1 was performed. As shown in Table 1, it can be seen that satisfactory results cannot be obtained even if any of the components is missing.

Example 6 A catalyst was prepared by changing the amounts of TiCl ₃ .1 / 3AlCl ₃ and VCl ₃ used in Example 1 to 5.4 g and 8.3 g, respectively. Polymerization was carried out in the same manner as in Example 1 using 9.2 mg of the solid catalyst to obtain 182 g of a polymer. Catalytic activity is 1
The solids were 9.8 kg / g solid and 74.0 kg / g (Ti + V), the MI was 0.19 and the density was 0.918.

TiCl The TiCl ₃ · 1 / 3AlCl ₃ 5.4g Comparative Example 4 Example 6
_The catalyst was prepared by changing to 5.0 g. Polymerization was carried out in the same manner as in Example 1 using 9.1 mg of the solid to give 1
46 g of polymer was obtained. The catalytic activity was 16.0 kg / g solid, 58.8 kg / g (Ti + V), MI was 0.59, and density was 0.920.

Examples 7 to 9 TiCl ₃ .1 / 3AlCl ₃ , VCl ₃ , boron compounds and silicon compounds shown in Table 2 were pulverized in the same manner as in Example 1 to obtain solid catalysts. Polymerization was carried out in the same manner as in Example 1, and the results shown in the table were obtained.

Example 10 A solid catalyst was obtained by grinding using 8.8 g of 1: 1 complex of TiCl ₃ .1 / 3AlCl ₃ and MgCl _{2 in} an amount of 4.7 g of VCl ₃ and 3.5 g of BCl _{3 in} Example 3. Polymerization was performed in the same manner as in Example 1 using 13.5 mg of the solid to give 259 g.
A polymer of Catalytic activity is 19.2kg / g solid, 11
0.0 kg / g (Ti + V), MI 0.19, density 0.
It was 920.

Example 11 TiCl ₃ used in Example 1 in the vibration mill described in Example 1
1/3 AlCl ₃ 8.0 g, VCl ₃ 6.3 g and B (OC ₂ H ₅ ) ₃ 1.
2 g was crushed for 6 hours, then 1.1 g of HSiCl ₃ was added and crushed for another 12 hours to obtain a solid catalyst. The solid 10.
Polymerization was carried out in the same manner as in Example 1 using 7 mg to obtain 244 g of a polymer. Catalytic activity is 22.8 kg
/ g solid, 95.3 kg / g (Ti + V), MI is 0.08,
The density was 0.918.

Examples 12-14 Using the catalyst prepared in Example 1, 1-butene is shown in Table-3.
Polymerization was carried out in the same manner as in Example 1 except that the α-olefin shown in Table 1 was replaced with the results shown in the table.

[Brief description of drawings]

FIG. 1 is a catalyst process diagram (flow chart diagram) according to the present invention.
Indicates.

Claims (2)

[Claims] 1. [A] (1) Titanium trichloride or a composite component of titanium trichloride and magnesium chloride, (2) vanadium trichloride, and (3) general formula B (OR ¹ ) _m X ¹
_3-m · Y _n (wherein R ¹ is a hydrocarbon group having 1 to 20 carbon atoms, X ¹ is a halogen atom, Y is an ether or a halogenophosphine oxide, m is 0 ≦ m ≦ 3, and n is 0
Or it is a number of one. In the presence of a catalyst system consisting of a solid catalyst component obtained by co-milling a boron compound represented by), and [B] an organoaluminum compound, ethylene is polymerized at a temperature equal to or higher than the melting point of polyethylene, or at least one of ethylene and ethylene is polymerized. A method for producing polyethylene, which comprises copolymerizing the above α-olefin. 2. [A] (1) Titanium trichloride or a composite component of titanium trichloride and magnesium chloride, (2) vanadium trichloride, (3) general formula B (OR ¹ ) _m X ¹ _3-m. Y
_n (wherein R ¹ is a hydrocarbon group having 1 to 20 carbon atoms, X ¹ is a halogen atom, Y is an ether or a halogenophosphine oxide, m is 0 ≦ m ≦ 3, and n is a number of 0 or 1) .), And (4) the general formula R ² _p Si (OR ³ ) _q X ² _4-pq (where R
² , R ³ represents a hydrocarbon group having 1 to 20 carbon atoms or a hydrogen atom, X ² represents a halogen atom, and p is 0 ≦ p ≦ 4, q
Has a relationship of 0 ≦ q ≦ 4 and 0 ≦ p + q ≦ 4. In the presence of a catalyst system consisting of a solid catalyst component obtained by co-grinding a silicon compound represented by), and [B] an organoaluminum compound, ethylene is polymerized at a temperature equal to or higher than the melting point of polyethylene, or at least one of ethylene and ethylene is polymerized. A method for producing polyethylene, which comprises copolymerizing the above α-olefin.