JPH0321606A - Production of polyolefin - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a method for producing polyolefins. More specifically, the present invention relates to a method for producing polyolefins with high polymerization activity and extremely narrow molecular weight distribution using a novel catalyst containing a magnesium compound and a titanium compound.

[Conventional technology]

It is known that catalyst systems containing magnesium and titanium compounds can be used for the polymerization of olefins. For example, in JP-A-5/-5ggg9, a catalyst system in which magnesium diethylate and titanium tetrabutyrate and ethylaluminum dichloride were reacted was disclosed.
2J9! proposed a catalyst system in which a hydrocarbon-insoluble solid obtained from the reaction of magnesium diethylate and a halogen-containing titanium compound was treated with an acid halide. When olefins were polymerized using these catalyst systems, the molecular weight distribution of the resulting polyolefins was somewhat narrow.

In JP-A-56-/AA2θB, a homogeneous hydrocarbon solution containing a titanium compound, a magnesium compound, and in some cases a hydroxy compound is converted into a silicon halide compound (R'
SiX4: R' is an alkyl, ap-p lyl or cycloalkyl group, X is a halogen atom,
A catalyst system has been proposed in which p is a number such that O≦p≦4. This catalyst system provides a polyolefin with an extremely narrow molecular weight distribution, but the polymerization activity is not sufficient.
In particular, the activity becomes low in high-temperature solution polymerization.

[Problem to be solved by the invention]

In general, the narrower the molecular weight distribution of a polyolefin, the better its mechanical properties, dimensional stability, etc. Therefore, the present inventors have been intensively studying the development of a polymerization catalyst that has high polymerization activity and can provide a polyolefin with an extremely narrow molecular weight distribution.

[Means to solve the problem]

As a result, in a system that combines a magnesium compound and a titanium compound, a specific compound is used as the titanium compound, and a homogeneous hydrocarbon eluate containing the magnesium compound, the titanium compound, and in some cases a hydroxy compound is prepared. The present inventors have discovered that by treating this with a halogen-containing silicon hydride compound under specific conditions, a catalyst system that provides a polyolefin with an extremely narrow molecular weight distribution and high polymerization activity can be obtained, resulting in the present invention.

That is, the gist of the present invention is that general 2 Mg (OR2). n
X: -m (wherein, R2 represents a parkyl, aryl or nocroalkyl group, X2 represents a halogen atom, m
Magnesium compounds represented by the general formula Tt(OR") X: (where n
-n R3 represents an alkyl, aryl or cycloalkyl group; where R4 represents an alkyl, aryl or cycloalkyl group), a homogeneous hydrocarbon solution containing a hydroxy compound represented by the general formula HtR'4-k-I
S L %' (wherein R represents a alkyl, aryl or cycloalkyl group, X1 represents a halogen atom, 1
(represented by a number of 3 or less)...Ethylene production using a catalyst system consisting of a combination of a hydrocarbon-insoluble solid obtained by treatment with a rogen-containing silicon hydride compound and an organoaluminum compound. Alternatively, there is provided a method for producing polyolefin, which comprises polymerizing a mixture of ethylene and other α-olefins.

To further explain the present invention in detail, general Mg (OR2)rr+X"z-rn(
In the formula, R2 represents an alkyl, aryl, or cycloalkyl group, X2 represents a norogen atom, and m is/or is used.

Specifically, R2 is methyl, ethyl, proyl, butyl,
Compounds such as pentyl, hexyl, octyl, phenyl, tolyl, xylyl, cyclohexyl, etc., which are alkyl, aryl, cycloalkyl groups with a carbon number of about 1/s, and where X2 is chlorine, bromine or iodine, such as dimethoxymagnesium, Examples include diethoxymagnesium, ethoxymagnesium chloride, diphenoxymagnesium, and the like. Among these, compounds in which m in the general formula is co are preferred. Among them, diethoxymagnesium is most suitable.

On the other hand, as a titanium compound, the general formula TL(OR3)nX:
-n (wherein R3 represents a parkyl, aryl or cycloalkyl group, X3 represents a halogen atom, and n is /, co or 3) is used. R3
, X3 include those exemplified above for R2 and X2. Specifically, compounds where n is 2 include jetoxydichlorotitanium, di-n-propoxydichlorotitanium,
Di-n-butoxydichlorotitanium, etc. Compounds where n is 3 include triethoxymonochlortitanium, tri-n
Monopropoxymonochlorotitanium, tri-n-butoxymonochlorotitanium, etc.; Examples of compounds where n is / include monopropoxytrichlortitanium, n-propoxytrichlortitanium, n-propoxytrichlortitanium.

Among these, the one with n of 3 prongs, especially the one with n of 3, is preferable. Among them, tri-n-butoxymonochlorotitanium is most suitable.

The hydroxy compound has the general formula R' OH (wherein,
A compound represented by R4 (representing a parkyl group, an aryl group or a cycloalkyl group) is used. Examples of the above R4 include those exemplified above for R2. Specifically, ethyl alcohol, n-propyl alcohol,
Improvyl alcohol, n-butyl alcohol, isoptel alcohol, n-pentyl alcohol, n-octyl alcohol, cyclohexanol, and the like can be mentioned.

In the method of the present invention, first a homogeneous hydrocarbon solution containing the above-mentioned magnesium compound, titanium compound, and optionally a hydroxy compound is prepared. Examples of the hydrocarbon used as a solvent include aliphatic hydrocarbons such as hexane and hebutane, alicyclic hydrocarbons such as cyclohexane, and aromatic hydrocarbons such as benzene, toluene and xylene. To prepare a hydrocarbon solution, it is preferable to mix a magnesium compound, a titanium compound, and in some cases a hydroxy compound in advance to prepare a homogeneous liquid, but there are no particular restrictions on the mixing order of the three components. It can be optional. After mixing, the mixture is preferably heated to a temperature of 1/00°C to 770°C to obtain a uniform liquid or a uniform solution of the hydroxy compound.

Next, a hydrocarbon solvent is added to obtain a hydrocarbon solution, and the resulting hydrocarbon solution may be used to remove a hydroxy compound if a hydroxy compound is added thereto, but usually without substantially removing the hydroxy compound. Treatment with a halogen-containing silicon hydride compound yields a hydrocarbon-insoluble solid.

As the halogen-containing silicon hydride compound, general formula Ht
RS - k- tS I
(indicates the number of groups) is used. Examples of R1 and X1 in the general formula include those exemplified above for R2 and X2. Among these, compounds in which X1 is a chlorine atom are preferred. Specific examples include trichlorosilane, methyldichlorosilane, ethyldichlorosilane,
Examples include butyldichlorosilane, phenyldichlorosilane, dichlorosilane, and the like. Among them, t=/, . The use of the chlorine-containing silicon hydride compounds of No. 2, especially trichlorosilane, gives favorable results.

・In the treatment with a chlorogen-containing silicon hydride compound, a chlorogen-containing silicon hydride compound is added to a homogeneous hydrocarbon solution. The reaction may be carried out at a temperature of 20-200°C, and since a hydrocarbon-insoluble solid is obtained, the solid may be separated and washed with a hydrocarbon solvent.

Therefore, the amounts of each component during the treatment with the halogen-containing silicon hydride compound can be selected arbitrarily, but the amounts of the magnesium compound, titanium compound, and in some cases, the hydroxy compound and the halogen-containing silicon hydride compound are determined by b and c, respectively. , d and a, m in the general formula
It is preferable to select a ratio that satisfies the relationship between SnSt and SnSt. Within this range, a catalyst can be obtained which provides a polyolefin with particularly high polymerization activity and an extremely narrow molecular weight distribution. Also, press the O button within the above range. If 05≦b/c≦da, a catalyst with particularly high polymerization activity can be obtained.

Next, as an organoaluminum compound used as a cocatalyst, for example, the general formula AlR;
5 represents an alkyl, aryl or cycloalkyl group,
X5 represents a halogen atom, and p represents a number of / to 3). R5, X5 is R
2. Examples include those exemplified as X2. Specifically, trialkylaluminum such as triethylaluminum, tri-n-propylaluminum, and triisoptylaluminium, and dialkylaluminum halide such as diethylaluminum chloride, di-n-propylaluminum chloride, diisoptylaluminum chloride, and diethylaluminum bromide are used. The preferred ratio of the hydrocarbon-insoluble solid and the organoaluminum compound is usually 0.7 to 0.7/Ti in terms of atomic ratio of IU/Ti.
θθ is used within the range of θθ. The catalyst system thus prepared is used to carry out the polymerization of ethylene or a mixture of haethylene and other α-ole7ynes. other α
-Olefins include α-olefins such as propylene, phthene/, bentene/, octene/, etc.

The polymerization reaction can be carried out by either solution polymerization or slurry monopolymerization carried out in an inert solvent, or gas phase polymerization carried out in the absence of a solvent. This is usually carried out by supplying an 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 benzane, hexane, heptane, octane, and inoctane, and aromatic hydrocarbons such as benzene and toluene are used.

The polymerization reaction is usually carried out at a temperature between room temperature and θθ℃ and at normal pressure.
When hydrogen is present in the polymerization reaction zone according to the method of the present invention, the effect of controlling the molecular weight by hydrogen is large, and it is easy to obtain a polymer with the desired molecular weight. can be obtained. The amount of hydrogen that should 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.

〔Effect of the invention〕

The molecular weight distribution of the polyolefin produced by using the catalyst system obtained by the method of the present invention as described above is extremely narrow. In other words, a polyolefin with an FR value of 2θ or less, which will be described later, can be easily obtained. Therefore, this polyolefin has excellent mechanical properties and dimensional stability, and the amount of grease wax by-product during polyolefin production is small. In addition, the polymer produced by the method of the present invention is characterized in that it is extremely difficult to generate 7 innosure because it is obtained using only hydrocarbon-soluble components of the reaction product of a magnesium compound and a titanium compound. .

〔Example〕

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 thereof.

In the examples, the polymerization activity K of the catalyst is K = (11 polymers)
/(g Catalyst) (hr) (Ky/cm" Olefin Pressure) Melt index is 2 at 90°C based on ASTM D/23g-!7T.
．． /bKq load measured M! It was expressed as Furthermore, the flow rate ratio (hereinafter abbreviated as PR) as a measure of molecular weight distribution is a value indicating the dependence of melt viscosity on shear stress, and is based on ASTM D 72.
According to 3g-37T, shear stress / 06dyne/cm
It is expressed as the ratio of the melt index measured for 2 and /θ' dyne /cm2, and if the FR is dog, the molecular weight distribution is wide, and if the FR is small, the molecular weight distribution is narrow. 1. FIG. 7 is a flowchart diagram to help understand the technical contents included in the present invention, and the present invention is not limited in any way by the chart diagrams as long as it does not deviate from the gist thereof. do not have.

Example/~2 Ammol of co-magnesium diethylate and a predetermined amount of tri-normalpoxy monochlorotitanium were mixed and heated at iqo°C.
The mixture was stirred for several hours to obtain a homogeneous liquid. Next, after cooling at 1 gO 0 C, a predetermined amount of benzene was added to form a homogeneous solution.

A predetermined amount of trichlorosilane was added thereto at 30° C., and then stirred for 3 hours at the temperature listed in Table 1 for ripening. The generated precipitate was washed with n-hexane and subjected to polymerization in the form of n-hexane slurry.

Next, /l autoclave normal hexane Sθθc
c was removed, and the above solid powder/θη was charged. After raising the temperature to 90°C, hydrogen was introduced at -2 KV7cm21, and triethylaluminum θ. /b mmol were introduced together with ethylene, and the total pressure was brought to g KS'/Crn2 (gauge pressure). Ethylene absorption was observed as ethylene was introduced, but ethylene was additionally introduced so as to maintain the total pressure at g Kf /cm2, and after 1 hour, the polymerization was stopped by injecting ethanol. The results obtained are shown in Table 1.

G in Table 1 is represent.

Example 3 In the polymerization of Example /, normal hexane/l was placed in a 2l autoclave, 0.32 mmol of diethylaluminium monochloride was charged, and hydrogen/ethylene in the gas phase was heated to /q5°C. The molar ratio is θ. Hydrogen was introduced in such a manner that 20 η of a solid catalyst component was introduced together with ethylene, and the total pressure was adjusted to /J Kg/cm2 (gauge pressure).

As ethylene was introduced, an increase in ethylene absorption temperature was observed, but ethylene was additionally introduced so that the total pressure was /3 Kf/Crn2, and the temperature was maintained at /30°C. 30
After a few minutes, the polymerization was stopped by injecting ethanol.

The results obtained are shown in Table 1.

Example 3 In the ethylene polymerization of Example 3, Ptene-7 was mixed when introducing and adding ethylene, and during the polymerization reaction, the molar ratio of hydrogen/ethylene in the gas phase was set to θ. Or, putene//ethylene molar ratio is 0. ．． Copolymerization of ethylene and putene was carried out in exactly the same manner except that 2 was used. As a result, MI=2.2, p[{-;/A, density 0.
90 g of ethylene butene/730 g of copolymer were obtained.O The solid catalyst component was prepared in exactly the same manner as in Comparative Example/Example/, except that silicon tetrachloride/g 9 mmol was used instead of trichlorosilane.

Polymerization was carried out in the same manner as in Example except that this solid catalyst component was used. The results are shown in Table/.

Comparative Example 2 Polymerization was carried out in exactly the same manner as in Example 3 except that the solid catalyst component of Comparative Example was used.

Show the results/ Shown below.

When a halogenated silicon compound that is not hydrogenated in this way is used, the activity becomes low.

[Brief explanation of drawings]

Figure 1 shows Flowchart illustrating one embodiment of the present invention This is a diagram. Mitsubishi Chemical Corporation

Claims (1)

[Claims] (1) General formula ▲ Numerical formula, chemical formula, table, etc. ▼ (In the formula, R^2 represents an alkyl, aryl or cycloalkyl group, and X^2
represents a halogen atom, m is 1 or 2), there are general formulas ▲ mathematical formulas, chemical formulas, tables, etc. ▼ (wherein R^3 represents an alkyl, aryl or cycloalkyl group, X^3
represents a halogen atom, n is 1, 2 or 3) and, in some cases, a titanium compound represented by the general formula R^
A homogeneous hydrocarbon solution containing a hydroxy compound represented by 4OH (in the formula, R ^
1 represents an alkyl, aryl or cycloalkyl group, X^1 represents a halogen atom, and k and l each represent a number from 1 to 3) obtained by treatment with a halogen-containing silicon hydride compound 1. A method for producing polyolefins, which comprises polymerizing ethylene or a mixture of ethylene and other α-olefins using a catalyst system comprising a combination of a hydrocarbon-insoluble solid and an organoaluminum compound. (2) As a magnesium compound, the general formula Mg(OR^2
)_2 and a compound represented by the general formula Ti(OR^3)_3X^3 as the titanium compound. (3) The method for producing a polyolefin according to claim 1 or 2, wherein magnesium diethylate is used as the magnesium compound and tri-normalptoxymonochlorotitanium is used as the titanium compound. (4) The method for producing a polyolefin according to any one of claims 1 to 3, in which trichlorosilane is used as the halogen-containing silicon hydride compound. (5) Claims 1 to 4 in which the amounts of the magnesium compound and the titanium compound satisfy 0.05≦b/c≦4, where b and c represent the number of moles, respectively. A method for producing a polyolefin according to any one of the above. (6) Using a catalyst system consisting of a combination of a solid catalyst component and an organoaluminum compound, ethylene or ethylene is used in an inert solvent that becomes a liquid phase under reaction conditions, and under conditions such that the formed polymer is dissolved in the medium. A method for producing a polyolefin according to any one of claims 1 to 5, which comprises polymerizing a polyolefin and another α-olefin. (7) The method for producing a polyolefin according to any one of claims 1 to 6, wherein the polyolefin obtained has a density of 0.85 to 0.92 g/cm^3.