JPH0725821B2 - Method for producing polyolefin - Google Patents

Description

TECHNICAL FIELD The present invention relates to a method for producing a polyolefin. More specifically, it relates to a method for producing a highly stereoregular polyolefin by using a TiCl ₃ solid component obtained by reducing TiCl ₄ and a catalyst composed of a titanium dialkyl compound having a bridge-type ligand.

[Prior Art and Problems Thereof] A titanium trichloride-based solid component can be used as a catalyst for olefin polymerization in combination with an organoaluminum compound, but the polymer produced is not sufficiently high in stereoregularity. Are known. In such a catalyst system, a method of adding various electron donors at the time of polymerization to improve stereoregularity has been known (John Boor, Jr., “Ziegler-
Natta Catalysts and Polymerizations ", Academic
Press).

In order to obtain a highly stereoregular polymer with this conventional titanium trichloride-based catalyst, an electron donor must be added as a third component in addition to the organoaluminum compound, and in addition the stereoregularity is increased. However, when the amount of the electron donor added is increased, the polymerization activity is lowered.

In addition, titanium trichloride solid catalyst and (Men-Cp) ₂ TiMe
A method of polymerizing an olefin with a catalyst containing a ₂ (n = 0,1) compound as a component has been known (Journal of Industrial Chemistry, No. 68).
Vol. 2, pp. 347 and 352 (1965), and Japanese Patent Laid-Open No.
No. 57-111307) In these articles and patents, there is no description using a titanium compound having a bridge-type ligand.

The present inventors, as a result of repeated research to solve the above problems, a TiCl ₃ solid component obtained by reducing TiCl ₄ and a catalyst composed of a titanium dialkyl compound having a bridge-type ligand, The inventors have found that a polymer having high stereoregularity can be produced even though it is a two-component system, and arrived at the present invention.

[Means for Solving the Problems] That is, the present invention provides (A) a TiCl ₃ solid component obtained by reducing TiCl ₄ , and (B) two groups selected from an indenyl group and a partial hydride thereof. A method for producing a polyolefin, characterized in that an olefin is polymerized using a catalyst comprising a titanium dialkyl compound having a bridge-type compound as a bidentate ligand having a group bonded through a lower alkyl group, is there.

The catalyst component TiCl ₄ used in the process of the present invention.
The method for producing the TiCl ₃ solid component (A) obtained by reducing the basic components is basically the method of reducing titanium tetrachloride with hydrogen, the method of reducing titanium tetrachloride with metallic aluminum, and the method of reducing titanium tetrachloride with organic aluminum. Reduction methods, etc., but many improved methods have been proposed. For example, (i) a method in which titanium trichloride obtained by reducing titanium tetrachloride with an organoaluminum compound is treated with an electron donor and titanium tetrachloride, and (ii) titanium tetrachloride and an organoaluminum compound are separately kept constant. A method of mixing and reacting two reaction liquids which have been previously mixed and reacted with an amount of a complexing agent, (iii) a reaction product of an organoaluminum compound and an electron donor is reacted with titanium tetrachloride, and then an electron is further added. A method of treating with a donor or the like. A TiCl ₃ solid component obtained by reducing TiCl ₄ produced by any method can be used, but more specifically, Japanese Patent Application No. 55-12875 (Japanese Patent Publication No. 59-28573) and The manufacturing method shown in Japanese Patent Application No. 55-30052 (Japanese Patent Application Laid-Open No. 56-125406) and the like can be mentioned.

The titanium dialkyl compound (B) which is another catalyst component used in the method of the present invention is a titanium dialkyl compound having a bridge type compound as a bidentate ligand. Examples of the bridge-type ligand include an ethylenebis (indenyl) group, an ethylenebis (4,5,6,7-tetrahydro-1-indenyl) group, a 1,3-propanedinylbis (indenyl) group, and a 1,3 -Propandinylbis (4,5,6,7-tetrahydro-1-indenyl) group and the like can be mentioned. The above-mentioned titanium dialkyl compound is a known titanium dihalide compound having a bridge type ligand (Journal of Organometallic Chem., 232
Vol. 233 (1982) and 322, 65 (1987),
It is obtained by reacting alkyllithium. Moreover, a methyl group, an ethyl group, etc. can be mentioned as an alkyl group.

Titanium dialkyl compounds that can be used in the method of the present invention include ethylenebis (indenyl) titanium dimethyl, ethylenebis (indenyl) titanium diethyl, ethylenebis (4,5,6,7-tetrahydro-
1-indenyl) titanium dimethyl, ethylenebis (4,5,6,7-tetrahydro-1-indenyl) titanium dimethyl, 1,3-propanedinylbis (indenyl)
Titanium dimethyl, 1,3-propanedinylbis (indenyl) titanium diethyl, 1,3-propanedinylbis (4,5,6,7-tetrahydro-1-indenyl) titanium dimethyl, 1,3-propanedinylbis (4 , 5,6,7-Tetrahydro-1-indenyl) titanium diethyl, etc., preferably ethylenebis (indenyl) titanium dimethyl and 1,3-propanedinylbis (indenyl) titanium dimethyl.

In the method of the present invention, the olefin used in the polymerization reaction is an α-olefin such as ethylene, propylene, 1-butene, 4-methyl-1-pentene, 1-hexene, 1-octene, 1-decene, It is also possible to subject two or more mixed components to polymerization. It is also possible to sequentially use the above-mentioned α-olefin and subject it to block copolymerization. Further, dienes such as butadiene, 1,4-hexadiene, 1,4-pentadiene, 1,7-octadiene, 1,8-nonidiene, 1,9-decadiene, or cyclopropane, cyclobutane, cyclohexene,
It is also effective for copolymerization of α-olefins with cyclic olefins such as norbornene and dicyclopentadiene.

As the polymerization method, either liquid phase polymerization such as suspension polymerization or solution polymerization or gas phase polymerization is possible. As a polymerization solution for liquid phase polymerization, pentane, hexane, octane, aliphatic hydrocarbons such as decane, cyclopentane,
Alicyclic hydrocarbons such as cyclohexane and cyclooctane, aromatic hydrocarbons such as benzene, toluene and xylene, petroleum fractions such as gasoline, kerosene, and light oil are used. Of these, aromatic hydrocarbons are preferable.

The olefin pressure of the reaction system is normal pressure to 50 kg / cm ² G, and the polymerization temperature is -50 to 230 ° C, preferably -20 to 200 ° C.

In the method of the present invention, TiC obtained by reducing (A) TiCl ₄
It is suitable that both the solid component ( ₃ ) and the titanium dialkyl compound (B) are fed to a polymerization vessel and stirred for 5 minutes to 3 hours, preferably 30 minutes to 2 hours before feeding the olefin. is there. Concentration of both components in the polymerization system,
The molar ratio is not particularly limited, but preferably,
The molar ratio of the Ti component of (B) / (A) is in the range of 0.1 to 100.

Isotactic index (II) used in the present invention
For example, in the production of a propylene polymer, it is a weight ratio with respect to the total amount 100 of the polymer of isotactic polypropylene that is insoluble in n-hexane (20 ° C.) and is a measure of stereoregularity. is there.

[Object of the Invention] As a titanium dialkyl compound to be combined with a solid TiCl ₃ component obtained by reducing TiCl ₄ , a bridge-type compound in which two groups selected from indenyl and its partial hydride are bonded via a lower alkyl group. According to the method of the present invention using a titanium dialkyl compound having as a bidentate ligand, as is clear from Examples and Comparative Examples described below,
Despite being a two-component system, a polymer with higher stereoregularity than conventional catalyst systems can be obtained.

[Examples] Next, the present invention will be specifically described with reference to Examples.

Example 1 TiCl ₃ obtained by reducing TiCl ₄ prepared by the method described in the specification of Japanese Patent Application No. 55-12875 with 500 ml of purified toluene in an autoclave made of sus having an internal volume of 1.5 L which has been sufficiently replaced with nitrogen.
As a solid component, a Ti component, 3.7 mmol, and ethylenebis (indenyl) titanium dimethyl 1.5 mmol were sequentially added, and the temperature was raised to 30 ° C. The mixture was stirred at this temperature for 1 hour, and then propylene was continuously introduced into this so that the total pressure was maintained at 1.0 kg / cm ² G, and polymerization was carried out for 2.0 hours. After the reaction
The catalyst component was decomposed with methanol, and the obtained polymer was dried. As a result, 33.0 g of a polymer was obtained, and II was 9
Was eight.

Example 2 TiCl ₃ obtained by reducing TiCl ₄ prepared by the method described in the specification of Japanese Patent Application No. 55-12875 with 500 ml of purified toluene in an autoclave made of sus having an internal volume of 1.5 L which has been sufficiently replaced with nitrogen.
As a solid component, Ti component, 3.0 mmol, and ethylenebis (indenyl) titanium dimethyl 1.5 mmol were sequentially added, and the temperature was raised to 30 ° C. After stirring at this temperature for 1 hour, propylene was continuously introduced into this so that the total pressure was maintained at 1.0 kg / cm ² G, and polymerization was carried out for 4.0 hours. After the reaction
The catalyst component was decomposed with methanol, and the obtained polymer was dried. As a result, 44.3 g of a polymer was obtained, and II was 9
Was 7.

Example 3 TiCl ₃ obtained by reducing TiCl ₄ prepared by the method described in the specification of Japanese Patent Application No. 55-12875 with 500 ml of purified toluene in an autoclave made of sus with a sufficient internal volume of 1.5 L and having an internal volume of 1.5 L.
As the solid component, Ti component, 1.2 mmol, and ethylenebis (indenyl) titanium dimethyl 0.55 mmol were sequentially added, and the temperature was raised to 50 ° C. After stirring at this temperature for 1 hour, propylene was continuously introduced into this so that the total pressure was maintained at 7.0 kg / cm ² G, and polymerization was carried out for 2.0 hours. After the reaction
The catalyst component was decomposed with methanol, and the obtained polymer was dried. As a result, 56.3 g of a polymer was obtained, and II was 9
Was 5.

Example 4 TiCl ₃ obtained by reducing TiCl ₄ prepared by the method described in the specification of Japanese Patent Application No. 55-12875 to 500 ml of purified toluene in an autoclave made of sus having an internal volume of 1.5 L which has been sufficiently replaced with nitrogen.
As a solid component, 1.6 mmol of Ti component and 1.0 mmol of 1,3-propanedinylbis (indenyl) titanium dimethyl were sequentially added, and the temperature was raised to 30 ° C. The mixture was stirred at this temperature for 1 hour, and then propylene was continuously introduced into this so that the total pressure was maintained at 1.0 kg / cm ² G, and polymerization was carried out for 2.0 hours.
After the reaction, the catalyst component was decomposed with methanol, and the obtained polymer was dried. As a result, 8.0 g of polymer was obtained,
The II was 97.

Example 5 TiCl ₃ obtained by reducing TiCl ₄ prepared by the method described in the specification of Japanese Patent Application No. 55-12875 with 500 ml of purified toluene in an autoclave made of sus with an internal volume of 1.5 L which has been sufficiently replaced with nitrogen.
As a solid component, 2.3 mmol of Ti component and 0.98 mmol of 1,3-propanedinylbis (indenyl) titanium dimethyl were sequentially added, and the temperature was raised to 30 ° C. After stirring at this temperature for 1 hour, propylene was continuously introduced into this so that the total pressure was maintained at 1.0 kg / cm ² G, and polymerization was carried out for 4.0 hours.
After the reaction, the catalyst component was decomposed with methanol, and the obtained polymer was dried. As a result, 21.0 g of a polymer was obtained, and II was 96.

Comparative Example 1 TiCl ₃ obtained by reducing TiCl ₄ prepared by the method described in the specification of Japanese Patent Application No. 55-12875 to 700 ml of purified hexane in an autoclave made of sus having an internal volume of 1.5 L which was sufficiently replaced with nitrogen.
The solid component was a Ti component, 0.4 mmol and 4.0 mmol of triethylaluminum were sequentially added, and the temperature was raised to 30 ° C. The mixture was stirred at this temperature for 1 hour, and then propylene was continuously introduced into this so that the total pressure was maintained at 1.0 kg / cm ² G, and polymerization was carried out for 2.0 hours. After the reaction, the catalyst component was decomposed with methanol, and the obtained polymer was dried. As a result, 8.6 g of a polymer was obtained and II was 87.

Comparative Example 2 TiCl ₃ obtained by reducing TiCl ₄ prepared by the method described in the specification of Japanese Patent Application No. 55-12875 to 700 ml of purified hexane in an autoclave made of sus having an internal volume of 1.5 L which was sufficiently replaced with nitrogen.
As a solid component, 0.4 mmol of diethyl component and 4.0 mmol of diethylaluminum chloride were sequentially added, and the temperature was raised to 30 ° C. The mixture was stirred at this temperature for 1 hour, and then propylene was continuously introduced into this so that the total pressure was maintained at 1.0 kg / cm ² G, and polymerization was carried out for 2.0 hours. After the reaction, the catalyst component was decomposed with methanol, and the obtained polymer was dried. As a result, 4.2 g of a polymer was obtained and II was 91.

[Brief description of drawings]

FIG. 1 is a flow sheet illustrating the steps of the method of the present invention.

Claims (3)

[Claims] 1. A TiCl ₃ solid component obtained by reducing (A) TiCl ₄ , and (B) a bridge in which two groups selected from an indenyl group and a partial hydride thereof are bonded via a lower alkyl group. A method for producing a polyolefin, which comprises polymerizing an olefin using a catalyst comprising a titanium dialkyl compound having a type compound as a bidentate ligand, the catalyst being a component. 2. The method according to claim 1, wherein the titanium dialkyl compound (B) is ethylenebis (indenyl) titanium dimethyl. 3. The (B) titanium dialkyl compound is 1,
The method according to claim 1, which is 3-propanedinylbis (indenyl) titanium dimethyl.