JPH07145210A - Production of ethylene polymer - Google Patents

Abstract

PURPOSE:To obtain an ethylene polymer having a moderately dispersed molecular weight distribution and useful for a fiber, a tape, etc., by the catalytic polymerization of ethylene or a mixture of ethylene with an olefin in the presence of a specific catalyst. CONSTITUTION:The objective polymer is obtained by the catalytic polymerization of (C) ethylene or a mixture of the component (C) with (D) a 3-12C alpha-olefin in the presence of a catalyst composed of (A) a solid catalyst component for olefin polymerization, obtained by reacting (i) a solid component composed of a magnesium dihalide, a titanium tetraalkoxide and/or a polytitanic acid ester and a polymeric silicon compound containing a recurring unit of the formula (R<1> is a 1-10C hydrocarbon residual group) with (ii) a halide of an element of the group 4a or 4b of the Periodic Table and further reacting the obtained reaction product with (iii) a boron halide and (B) an organoaluminium compound.

Description

Detailed Description of the Invention

BACKGROUND OF THE INVENTION

FIELD OF THE INVENTION The present invention relates to a process for producing an ethylene polymer, which makes it possible to obtain a polymer having a moderately broadened molecular weight distribution.

[0002]

2. Description of the Related Art Ethylene polymers are used for different purposes depending on their molecular weight distribution. For those with a wide molecular weight distribution, hollow molded products such as pipes, for those with a medium molecular weight distribution, fibers, tapes, etc. In addition, those having a narrow molecular weight distribution are often used for injection molded products such as bottle caps and buckets.

Solid catalyst components composed of magnesium halides and titanium halides, which have hitherto been known to have high activity, generally give ethylene polymers having a narrow molecular weight distribution, so that they can be used in injection molded articles such as bottle caps and buckets. A catalyst component that is suitable for production, but generally not suitable for the production of other applications such as those mentioned above.

In recent years, it has been necessary to develop a catalyst that gives a polymer having a wide molecular weight distribution in order to expand the range of applications, such as a method of using many kinds of transition metal compounds or a method of supporting a catalyst component on an inorganic oxide carrier. There have been many inventions using (for example, Japanese Patent Publication Nos. 52-37037 and 53-85).
88, 55-8006, 57-45247,
58-13084 and 62-58364, etc.).

The present inventors have found that a solid catalyst component which is already very excellent in particle morphology and which is particularly suitable for slurry polymerization or gas phase polymerization is (1) silicon halide, (2) titanium halide or (3) halogen. A method for producing by treating with titanium oxide, hydropolysiloxane or the like has been proposed (for example, JP-A-58-127706,
61-285203, 61-285204, 61-285205, 57-180612 and 5
Nos. 8-5309 and 58-5311). These catalysts are useful as such, but further improvement is desired in that the produced polymer may have a narrow molecular weight distribution or the catalytic activity may not be sufficiently high. It was a thing.

On the other hand, a method of using a halide of boron in synthesizing a catalyst component composed of Ti, Mg and Cl has been reported, for example, Japanese Patent Publication No. 62-56885.
In the publication, Mg _m Ti (OR) _n X _p [ED] _q is diluted with an inert carrier, treated with BR _c X'3 _-c , and then A
_{l (R ") d X"} e H catalyst composition for ethylene polymerization treatment with an activating agent of _f is disclosed. However,
To the best knowledge of the inventors, the ethylene polymers obtained using such catalyst compositions usually have a low melt flow rate and have been less than satisfactory.
Also, Japanese Patent Publication No. 63-66842 discloses a method of treating a reaction product of a Mg compound and a compound containing a Ti-OR bond with a mixture of a reducing agent and a halogenating agent. Although BCl ₃ is exemplified as the agent, there is no specific use example, and there is no suggestion as to whether or not the molecular weight distribution is affected by BCl ₃ . In addition, JP-A-1-158005 and JP-A-3-2
No. 07705 and Japanese Patent Publication No. 1-49289 disclose the possibility of using a halide of boron, but do not show any effect on the molecular weight distribution.

[0007]

SUMMARY OF THE INVENTION The present invention aims to obtain an ethylene polymer having a moderately broad molecular weight distribution, which is achieved by using a specific catalyst. To do.

[0008]

[Means for Solving the Problems]

[Summary of the Invention] <Summary> Therefore, in the method for producing an ethylene polymer according to the present invention, ethylene or ethylene and an α-olefin having 3 to 12 carbon atoms are used in a catalyst comprising the following components (A) and (B). Is brought into contact and polymerized.

Component (A) A solid catalyst component for olefin polymerization obtained by bringing the following component (A-1) into contact with the component (A-2) and bringing the contact product into contact with the component (A-3). (A-1) The following components (A-1-i) and (A-1-ii)
And (A-1-iii) solid component (A-1-i) magnesium dihalide (A-1-ii) titanium tetraalkoxide and / or polytitanate (A-1-iii) A polymer silicon compound having a repeating unit represented by (A-2) halide of group IVa or IVb of the periodic table (A-3) halide component of boron (B) organoaluminum compound <Effect> According to the present invention It is possible to obtain an ethylene polymer having a broader molecular weight distribution. Such ethylene polymers are particularly useful as resins for producing fibers and tapes. [Detailed Description of the Invention] [I] Catalyst The catalyst used in the present invention comprises a specific component (A) and a specific component (B). Here, "consisting of" does not mean that the components are only those listed above (that is, A and B), and that other components coexist within a range that does not impair the effects of the present invention. Please understand that the purpose is not to exclude. <Component (A)> The component (A) is obtained by contacting the following component (A-1) with the component (A-2), and contacting the resulting product with the component (A-).
It is a solid catalyst component for olefin polymerization obtained by contacting 3).

As used herein, the term "obtainable by contacting" means that components (A-1) to (A-3) alone are contacted, and components other than components (A-1) to (A-3) are included. It also means a product obtained by contacting the objective component of Component (A-1) 1) Constituent component The component (A-1) is a solid component consisting of the following component (A-1-i), component (A-1-ii) and component (A-1-iii). Is. Here, "consisting of" does not mean that the components are only those listed above (that is, (A-1-i), (A-1-ii) and (A-1-iii)). ,
It does not preclude the coexistence of other purposeful ingredients.

This solid catalyst component (A-1) is neither a magnesium dihalide nor a complex of magnesium dihalide with titanium tetraalkoxide or polytitanate and is another solid. At present, its content has not been sufficiently analyzed, but according to the composition analysis result, this solid composition contains titanium, magnesium, halogen and silicon. The specific surface area of this solid catalyst component (A-1) is often small and usually 10
m ² / g or less, and according to the result of X-ray diffraction, no peak characterizing magnesium dihalide was found in this solid component (A). It seems to be another compound.

(1) Component (A-1-i) This is a dihalogenated magnesium, and specific examples thereof include MgF ₂ , MgCl ₂ and MgBr ₂ . Among them, MgCl ₂ is preferable.

(2) Component (A-1-ii) This is titanium tetraalkoxide and / or polytitanate. As the alkoxy in the titanium tetraalkoxide molecule, an alkoxy having about 2 to 20 carbon atoms, preferably 2 to 10 carbon atoms is used.

Examples of titanium tetraalkoxides include Ti (OC ₂ H ₅ ) ₄ and Ti (O-iC ₃ H ₇ ).
_{4, Ti (O-nC 3} H 7) 4, Ti (O-nC
_{4 H 9) 4, Ti (} O-iC 4 H 9) 4, Ti (O-t
_{C 4 H 9) 4, Ti} (O-C 5 H 11) 4, Ti (O-C
_{6 H 13) 4, Ti (} O-nC 7 H 15) 4, Ti (O-C
_{8 H 17) 4, Ti (} O-C 10 H 21) 4, and the like.

As the polytitanate,

[0016]

[Chemical 1] The one represented by is used. Here, R ^3's are each independently a hydrocarbon group, particularly about 1 to 20 carbon atoms, and particularly 1 to
About 6 and n is a number of 2 or more, especially 2 to 10
The degree is something. Specifically, for example, tetra-normal butyl polytitanate (degree of polymerization n = 2-1
0), tetra-normal hexyl polytitanate (polymerization degree n = 2 to 10), or tetra-octyl polytitanate (polymerization degree n = 2 to 10). (3) Component (A-1-iii) This polymer silicon compound has the formula It has a structure represented by as a repeating unit.
Here, R ¹ is a hydrocarbon residue having 1 to 10 carbon atoms, particularly about 1 to 6 carbon atoms, preferably an alkyl group, a phenyl group and an alkyl-substituted phenyl group. Therefore, specific examples of the polymer silicon compound having such a structural unit include methylhydropolysiloxane, ethylhydropolysiloxane, phenylhydropolysiloxane, cyclohexylhydropolysiloxane and the like.

The degree of polymerization of the polymer silicon compound is not particularly limited, but considering handling, it is preferable that the viscosity is about 10 centistokes to 100 centistokes. Although the terminal structure of the hydropolysiloxane does not have a great influence, it is preferably blocked with an inert group such as a trialkylsilyl group.

2) Production Component (A-1) comprises the above components ((A-1-i) to (A-1)).
-1-iii)), it can manufacture.

(1) Amount Ratio The amount of each component used may be arbitrary as long as the effects of the present invention are recognized, but generally, the following ranges are preferable.

The amount of titanium tetraalkoxide and polytitanate (component (A-1-ii)) used (total amount in the case of combined use) is magnesium dihalide (component (A-II)).
The molar ratio to (-1-i)) may be in the range of 0.1 to 10, and preferably in the range of 1 to 4.

Polymer Silicon Compound (Component (A-1-ii
i)) is used in an amount of magnesium dihalide (component (A
With respect to (-1-i)), the molar ratio may be in the range of 1 × 10 ^{−2 to} 100, preferably in the range of 0.1 to 10.

(2) Contact method The solid component (A-1) of the present invention is obtained by contacting the above-mentioned three components. The contact of the three components can be performed by any generally known method. Generally, -1
The contact may be performed in the temperature range of 00 ° C to 200 ° C. The contact time is usually about 10 minutes to 20 hours.

The contact of the above-mentioned three components is preferably carried out with stirring, and it is also possible to carry out the contact by mechanical pulverization using a ball mill, a vibration mill or the like. The order of contacting the three components can be arbitrary as long as the effect of the present invention is recognized, but it is common to contact the magnesium dihalide with the titanium tetraalkoxide and then the polymeric silicon compound. The contact of the three components can also be performed in the presence of a dispersion medium. Examples of the dispersion medium in that case include hydrocarbons, halogenated hydrocarbons, dialkyl polysiloxanes and the like. Specific examples of hydrocarbons include hexane, heptane, toluene, cyclohexane, and the like, and specific examples of halogenated hydrocarbons include n-butyl chloride, 1,2-dichloroethylene, carbon tetrachloride, chlorobenzene, and the like. Specific examples of the dialkyl polysiloxane include dimethyl polysiloxane and methyl-phenyl polysiloxane.

At this time, as described in JP-A-59-80406, alcohol, organic acid ester and other electron-donating compounds can be made to coexist for controlling the catalyst properties.

The solid component (A-1) is the component (A-2),
Before contacting with (A-3), unnecessary components, for example, unreacted components of components (A-1-ii) and (A-1-iii) are preferably washed and removed. As the cleaning solvent to be used, an appropriate solvent can be selected from the above dispersion media. Therefore, if the components (A-1-i) to (A-1-iii) are contacted in the dispersion medium, the washing operation can be reduced.

Component (A-2) Component (A-2) is a halide of group IVa or IVb of the periodic table. Of these, preferred are halides of silicon or titanium.

The halide of silicon has the general formula SiX _a
Compounds represented by R ^{4 _4-a} is typical. here,
R ⁴ represents a hydrocarbon residue, preferably a hydrocarbon residue having 1 to 10 carbon atoms, or a hydrocarbyloxy group, preferably an alkoxy or aryloxy group having 1 to 10 carbon atoms. Further, X represents halogen and a represents a number of 0 <a ≦ 4.
Among these, trihalogenated silicon and tetrahalogenated silicon having a = 3 and a = 4 in the above general formula are preferable.

Specific examples of such a compound include SiCl ₄ , SiBr ₄ , CH ₃ SiCl ₃ , and (C ₂ H
_{5) SiCl 3, (C 4} H 9) SiCl 3, Ph-Si
-Cl ₃ (Ph: _{phenyl), (C 2 H 5)} 2 SiCl
₂ , (C ₂ H ₅ O) SiCl ₃ , (C ₂ H ₅ O) ₂ Si
Cl ₂ , CH ₃ (C ₂ H ₅ O) SiCl ₂ , C ₂ H
₅ (C ₂ H ₅ O) SiCl _{2 and the} like.

Titanium halides have the general formula TiX _b
The compound represented by (OR ⁵ ) _4-b is typical. Here, R ⁵ is a hydrocarbon residue, preferably having 1 carbon atom
10 hydrocarbon residues. X is halogen, b
Indicates a number of 0 <b ≦ 4. Among these, titanium trihalides and titanium tetrahalides are preferable.

Specific examples of such compounds include TiCl ₄ , TiBr ₄ , Ti (OC ₂ H ₅ ) Cl ₃ ,
Ti (OC ₂ H ₅ ) ₂ Cl ₂ , Ti (OC ₂ H ₅ ) ₃ C
1, Ti (OiC ₃ H ₇ ) Cl ₃ , Ti (OnC
_{4 H 9) Cl 3, Ti} (OnC 4 H 9) 2 Cl 2, Ti
(OC ₂ H ₅ ) Br ₃ , Ti (OC ₂ H ₅ ) (OC ₄ H
_{9) Cl 2, Ti (OnC} 4 H 9) 3 Cl, Ti (O-
C ₆ H ₅ ) Cl ₃ , Ti (OC ₅ H ₁₁ ) Cl ₃ , Ti
_(OC 6 H ₁₃₎ Cl _3, and the like.

The above-mentioned silicon halide and titanium halide can be used in combination within each group and / or between each group.

Component (A-3) (A-3) is a halide of boron. Such a “halogen compound of boron” means a compound in which at least one of the valences 3 of boron is satisfied by halogen. When all of the valences of boron are not satisfied by halogen, the group other than halogen that should satisfy the valences of the element is a hydrocarbon residue having about 1 to 12 carbon atoms, for example, the number of carbon atoms. Examples thereof include an alkoxy group having 1 to 12 carbon atoms, an allyloxy group having 1 to 12 carbon atoms, an alkylamide group having 1 to 12 carbon atoms, a hydroxyl group and a hydride group.

Specific examples of the component (A-3) include boron trichloride, boron tribromide, boron triiodide, methyldibromoboron, ethyldibromoboron, isopropyldibromoboron, butyldibromoboron, hexyldibromoboron and octyl. Dibromoboron, cyclohexyldichloroboron, phenyldichloroboron, dimethyldichloroboron, diethyldichloroboron, dibutylchloroboron, diphenylchloroboron, methoxydichloroboron, ethoxydichloroboron, butoxydichloroboron, phenoxydichloroboron, diethoxychloroboron, diphenoxy. Examples thereof include dichloroboron.

Preferred among these are boron trichloride, boron tribromide and boron triiodide.

Particularly preferred is boron tribromide. <Synthesis of Component (A)> Component (A) is obtained by contacting the contact product of component (A-1) and component (A-2) with component (A-3).

(1) Amount Ratio The amount of each component used is arbitrary as long as the effects of the present invention are recognized, but the following ranges are generally preferable.

The amount of the component (A-2) used is the amount of the component (A-
The molar ratio to Ti in 1) may be in the range of 0.01 to 20, preferably 0.1 to 10.

The amount of the component (A-3) used is the amount of the component (A-
As the amount of B in 3), the molar ratio is 0.1 to 20, preferably 0.1 to Ti with respect to Ti in the solid component after the treatment of the component (A-2).
5-10.

(2) Contact method Component (A-2) and component (A) with respect to component (A-1)
-3), the contact temperature is -50 ° C to 2 at any stage.
It is usual to carry out at 00 ° C. for about 5 minutes to 20 hours.

The contact of each component is preferably carried out with stirring, and it is also possible to carry out the contact by mechanical pulverization with a ball mill, a vibration mill or the like, but it is preferably carried out in the presence of a dispersion medium. The dispersion medium at that time is the component (A-
It can be selected and used from those that can be used when manufacturing 1).

After the reaction between the component (A-1) and the component (A-2), unnecessary components such as unreacted substances in the reaction mixture are generally and preferably removed by washing. In addition, a method of washing and removing unnecessary components such as unreacted substances in the reaction mixture after the reaction of the component (A-3) is generally adopted and is preferable. As the washing solvent used, a dispersion medium that can be used in the production of the solid component (A-1) is used.

The component (A) used in the present invention may be the solid component obtained as described above as it is, or the solid component may be contacted with an olefin in the presence of an organoaluminum compound, if necessary. It may be one which has been subjected to different prepolymerization.

When the component (A) is preliminarily polymerized, the prepolymerization conditions of the olefins for producing the component (A) are not particularly limited, but the following conditions are generally preferable. . The polymerization temperature is preferably 0 to 100 ° C, more preferably 10 to 90 ° C. As the polymerization amount, 0.001 to 50 g of olefins are preferably polymerized per 1 g of the solid component, and more preferably 0.1 to 10 g of olefins are polymerized.

As the organoaluminum compound component which may be used in the prepolymerization, those generally known as an organoaluminum compound of a Ziegler type catalyst can be used. As a specific example, the compound shown in the section of the description of the component (B) described later, that is, an organoaluminum compound can be used.

The amount of the organoaluminum component used during the prepolymerization is Al / A relative to the Ti component in the solid component (A).
Ti (molar ratio) is preferably 0.2 to 20, and 0.5 to 1
0 is more preferable.

Examples of olefins used in the prepolymerization include ethylene, propylene, 1-butene, 1-hexene and 3-methyl-1-butene, and a mixture thereof. <Component (B)> The component (B) is an organoaluminum compound. Specific examples of organoaluminum compounds suitable for use as component (B) include R ⁶ _3-p AlX _p or R ⁷ _3-q Al (OR ⁸ ) _q (wherein R ⁶ and R
⁷ is a hydrocarbon residue or hydrogen atom having about 1 to 20 carbon atoms which may be the same or different, R ⁸ is a hydrocarbon residue,
X is halogen, and p and q are 0 ≦ p <3 and 0 <, respectively.
q <3 is a number). Specifically, (a) trialkylaluminum, for example, trimethylaluminum, triethylaluminum, triisobutylaluminum, trihexylaluminum, trioctylaluminum and tridecylaluminum, and the like, (b) alkylaluminum halide, for example,
(A) Dialkyl aluminum hydrides such as diethyl aluminum monochloride, diisobutyl aluminum monochloride, ethyl aluminum sesquichloride and ethyl aluminum dichloride, (di) aluminum alkoxides such as diethyl aluminum hydride, eg diethyl aluminum ethoxide And diethylaluminum phenoxide. Among them, trialkylaluminum is preferable, and one having a hydrocarbon group having 1 to 4 carbon atoms is particularly preferable.

Two or more of these organoaluminum compounds can be used in combination within each group and / or between each group. For example, combined use of triethyl aluminum and diethyl aluminum alkoxide, combined use of diethyl aluminum monochloride and diethyl aluminum ethoxide, combined use of ethyl aluminum dichloride and diethyl aluminum ethoxide, combined use of triethyl aluminum and diethyl aluminum ethoxide and diethyl aluminum monochloride, etc. Can be given. [II] Polymerization of ethylene Copolymerization of ethylene or ethylene and an α-olefin is carried out by using a slurry polymerization method, a gas phase polymerization method or a solution polymerization method, and continuous polymerization, batch polymerization or preliminary polymerization is carried out. It is also applied to the method. As the solvent in the case of slurry polymerization, butane, pentane, hexane, heptane,
Hydrocarbons such as cyclohexane, benzene and toluene are used. The polymerization temperature is from room temperature to 200 ° C, preferably 50 to 120 ° C. As is well known, molecular weight control is generally performed by using hydrogen.

The polymerization pressure is, 250 kg / cm ² from the atmospheric pressure, preferably to 50 kg / cm ^2.

The α-olefin copolymerized with ethylene preferably has 3 to 10 carbon atoms. Such α-
The olefin is usually used in an amount up to about 10 mol% of the final polymer.

The ethylene polymer of the present invention thus obtained has a medium molecular weight distribution. That is, the ethylene polymer according to the present invention has a melt index (ASTM) under a load of 10 kg and a load of 2.16 kg.
The ratio FR of D-1238-73) is: 9 or more in a homopolymer.

[0051]

【Example】

<Example 1> (1) Synthesis of component (A) 100 ml of dehydrated and deoxygenated n-heptane was introduced into a flask having an inner diameter of 10 cm which had been sufficiently replaced with nitrogen.
Next, 0.1 mol of MgCl ₂ and Ti (O-nC
0.2 mol of ₄ H ₉ ) ₄ was introduced and reacted at 95 ° C. for 1 hour. The diameter of the stirring blade used at that time was 6 cm.
After completion of the reaction, the temperature was lowered to 40 ° C., 15 ml of methylhydrogenpolysiloxane was introduced, and the reaction was carried out for 3 hours at a stirring rotation speed of 20 rpm.

After completion of the reaction, the produced solid component was washed with n-heptane, a part thereof was taken out, and the average particle size was measured by the sedimentation method. As a result, it was 25.5 μm. T
The i carrying ratio was 14.7 wt%.

Then, 50 g of the above solid component was placed in a 500 cc flask that had been sufficiently replaced with N ₂ , and heptane was added to make the total 250 cc. 1.07 g of ethylaluminum dichloride (molar ratio of Ti to 0.055) was added dropwise at 30 ° C., and 31 cc of SiCl ₄ (1.8 molar ratio of Ti) was further added.
Was added dropwise and reacted for 3 hours, then the temperature was raised to 90 ° C. and the reaction was further continued for 3 hours. Then, it was thoroughly washed with heptane. The Ti support rate was 6.27 wt%.

Next, 5.0 g of the above solid component was taken, and heptane was added thereto to make 100 cc. At 35 ° C, 4.9 g of boron tribromide (molar ratio of Ti to 3) was added dropwise, and the mixture was reacted at 35 ° C for 2 hours. Then, it was thoroughly washed with heptane to obtain a catalyst. The Ti loading of this product is 4.54 wt%
Met. (3) Polymerization of Ethylene 800 ml of sufficiently dehydrated and deoxygenated n-heptane was introduced into a stainless steel autoclave having an internal volume of 1.5 liter equipped with a stirring and temperature control device,
Subsequently, 270 mg of triethylaluminum and 10 mg of the catalyst synthesized above were successively introduced.

The temperature is raised to 90 ° C., and the partial pressure of hydrogen is 2.1 kg /
cm ^2, further to the 4.9 kg / cm ² introduced ethylene, was 7 kg / cm ² G at a total pressure. Polymerization was carried out for 2 hours while supplying ethylene and maintaining this total pressure. After completion of the polymerization, ethylene and hydrogen were purged, the contents were taken out from the autoclave, the polymer slurry was filtered, and dried overnight. As a result, 105.2 g of a polymer was obtained (solid catalyst yield: PY = 10.20 g-PE / g-solid catalyst). MI (melt index at 2.16 kg load) is 2.65, FR (10 kg load and 2.16 kg)
It is a measure of the molecular weight distribution by the melt index ratio of the load. The larger this value, the wider the molecular weight distribution) was 9.7.

Comparative Example-1 Preparation of catalyst components and polymerization of ethylene were carried out in the same manner as in Example-1 except that the treatment with boron tribromide was not carried out.

As a result, 102.3 g of polymer was obtained. The MI of this polymer is 1.39 and the FR is 8.
It was 4.

Comparative Example-2 In Example-1, SiCl was used instead of boron tribromide.
Preparation of catalyst components and polymerization of ethylene were carried out in the same manner as in Example 1 except that ₄ was used in a molar ratio of 3 to Ti.

The Ti content of the catalyst component was 3.96 wt%, and 58.2 g of polymer was obtained by polymerization using this catalyst component. The MI of this polymer was 1.50 and the FR was 8.0.

Example-2 Preparation of the catalyst component and ethylene conversion were carried out in the same manner as in Example-1 except that the amount of boron tribromide used during the catalyst synthesis was changed to the molar ratio of Ti to 2. Polymerization was carried out.

The Ti content of the catalyst component was 4.57 wt%.
And 112. by polymerization using this catalyst component.
3 g of polymer was obtained. The MI of this polymer is 2.
22 and FR was 9.4.

Example-3 In Example-1, instead of boron tribromide in the catalyst synthesis, a solution of boron trichloride in dichloromethane (1.0 M) was used.
Preparation of catalyst components and polymerization of ethylene were carried out in the same manner as in Example 1 except that was used in a molar ratio of 3 to Ti.

The Ti content of the catalyst component was 4.13 wt%, and 92.1 g of polymer was obtained by the polymerization using this catalyst component. The MI of this polymer is 1.88,
FR was 9.3.

Example-4 (1) Synthesis of Component A n was dewatered and deoxygenated in a flask which had been sufficiently replaced with nitrogen.
-Introduce 100 ml of heptane, then MgC
l ₂ 0.1 _{mol, Ti (O-nC 4 H} 9) 4 0.2
Mol was introduced and reacted at 95 ° C. for 2 hours. After the reaction,
The temperature was lowered to 40 ° C., 12 ml of methylhydrogenpolysiloxane (20 centistokes) was then introduced, and the reaction was carried out for 3 hours. The solid component formed was washed with n-heptane.

Then, in a flask that had been sufficiently replaced with nitrogen,
The solid component synthesized above was introduced in an amount of 60 mmol in terms of Mg atom, and n-heptane was further added to make 200 cc. Then, 22 mmol of SiCl _{4 was} added dropwise at 25 ° C. over 15 minutes. Further, 85 mmol of TiCl _{4 was} added at 25 ° C.
At 30 minutes, the temperature was raised and the reaction was carried out at 50 ° C. for 3 hours.

After completion of the reaction, the product was thoroughly washed with n-heptane.

The Ti loading of this product was 10.9 wt%.
Met.

Next, 8.0 g of the above solid component was taken, and heptane was added to this to make 100 cc. At 25 ° C., 9.1 g of boron tribromide (molar ratio to Ti: 2) was added dropwise, the temperature was raised, and the reaction was carried out at 50 ° C. for 2 hours. Then, it was thoroughly washed with heptane. The Ti loading of this product was 2.01 wt%. (2) Preliminary Polymerization 4 g of the above-mentioned solid catalyst component diluted with 500 cc of sufficiently dehydrated and deoxygenated n-heptane was introduced into a stainless steel autoclave having an internal volume of 1.5 liter equipped with a stirring and temperature control device. Then, 0.6 g of triethylaluminum and 0.
6 g was introduced. Next, the partial pressure of hydrogen is 1.2 kg / c
Introducing m ² and ethylene at 16 g / hr, 1.
It was polymerized for 0 hours. After the polymerization, ethylene and hydrogen were purged, the contents were taken out from the autoclave, and thoroughly washed with heptane.

A prepolymerized catalyst containing 3.9 g of polymer per gram of catalyst was obtained. (3) Polymerization of Ethylene 800 ml of sufficiently dehydrated and deoxygenated n-heptane was introduced into a stainless steel autoclave having an internal volume of 1.5 liter equipped with a stirring and temperature control device,
Subsequently, 270 mg of triethylaluminum and 49 mg of the prepolymerized catalyst synthesized above were successively introduced.

The temperature was raised to 85 ° C., and the partial pressure of hydrogen was 2.1 kg /
cm ^2, further to the 4.9 kg / cm ² introduced ethylene, was 7 kg / cm ² G at a total pressure. Polymerization was carried out for 2 hours while supplying ethylene and maintaining this total pressure. After completion of the polymerization, ethylene and hydrogen were purged, the contents were taken out from the autoclave, the polymer slurry was filtered, and dried overnight.

As a result, 93.1 g of polymer was obtained.
This had an MI of 3.64 and an FR of 9.5.

Comparative Example-3 Preparation of catalyst components and polymerization of ethylene were carried out in the same manner as in Example-4 except that the treatment with boron tribromide was not carried out.

At this time, the prepolymerized catalyst contained 3.9 g of the polymer per 1 g of the catalyst and 1 g of the catalyst as in Example-4.

88.1 g of polymer were obtained. This product had MI of 3.12 and FR of 8.2.

[0075]

Industrial Applicability According to the present invention, it is possible to obtain an ethylene polymer having a broader molecular weight distribution as described above in the section "Summary of the Invention".

[Brief description of drawings]

FIG. 1 is a flow chart diagram for helping understanding of the technical content of the present invention regarding a Ziegler catalyst.

Claims (1)

[Claims] 1. A catalyst comprising the following components (A) and (B) is added to ethylene or ethylene and α having 3 to 12 carbon atoms.
-A method for producing an ethylene polymer, which comprises contacting and polymerizing an olefin. Component (A) A solid catalyst component for olefin polymerization obtained by bringing the following component (A-1) into contact with the component (A-2) and bringing the contact product into contact with the component (A-3). (A-1) The following components (A-1-i) and (A-1-ii)
And (A-1-iii) solid component (A-1-i) magnesium dihalide (A-1-ii) titanium tetraalkoxide and / or polytitanate (A-1-iii) A polymer silicon compound having a repeating unit represented by (A-2) halide of group IVa or IVb of the periodic table (A-3) halide component of boron (B) organoaluminum compound