JP2543238B2 - Olefin prepolymerization method - Google Patents

Description

TECHNICAL FIELD The present invention relates to a method for prepolymerizing olefin which is suitable for obtaining polypropylene having excellent transparency.

(Prior Art and Problems to be Solved by the Invention) Polypropylene is widely used as a resin having excellent mechanical properties, moldability, and chemical stability. However, transparency is generally inferior to resins such as polystyrene and polyvinyl chloride because of high crystallinity.

Several proposals have been made so far in an attempt to improve the transparency of polypropylene. For example, by adding a nucleating agent such as sorbitol derivative, sodium salt or potassium salt of aromatic carboxylic acid to polypropylene, the spherulites of the molded product can be made small and uniform, thereby improving the transparency of the molded product. Known (JP-A-58-80392, JP-A-55-12460). However, these organic nucleating agents have a problem that bleeding out from the resin causes roll stains during molding, particularly during molding of a sheet or a biaxially stretched film, and that odor is generated during processing. . Further, the aromatic carboxylates have a problem that they are hydrolyzed or react with other additives to color the resin.

On the other hand, there is known a method for improving the transparency of polypropylene by prepolymerizing a small amount of branched α-olefin such as 3-methylbutene-1 with a conventional stereoregular catalyst (Japanese Patent Laid-Open No. 63-69809). , JP-A-62-1738). According to this method, the transparency improving effect of polypropylene can be obtained without fear of bleeding out.

However, when polypropylene is used for a film or the like, such a degree of transparency is not sufficiently satisfactory, and more excellent transparency is required.

(Means for Solving the Problems) In view of the above problems, the present inventors have conducted intensive studies, and as a result, found that the above object can be achieved by performing a specific prepolymerization, and to complete the present invention. I arrived.

That is, the present invention has the following components A, B and C A. titanium compound B. organoaluminum compound C. formula (I) _{R n Si (OR ') 4} -n (I) In the presence of an organosilicon compound represented by the following formula, prepolymerization of olefin is carried out in multiple stages, different organosilicon compounds are used in each prepolymerization stage, and in at least one stage of each prepolymerization stage, the following formula [A] Or the following formula [B] CH ₂ = CH-R ⁴ [B] Is a prepolymerization method of olefin, which comprises polymerizing an unsaturated compound represented by

As the titanium compound [A] used in the prepolymerization method of the present invention, compounds known to be used for the polymerization of olefins can be adopted without any limitation. Particularly, a titanium compound containing titanium, magnesium and halogen as components and having high catalytic activity is preferable. Such a titanium compound having a high catalytic activity is one in which various halogen compounds, particularly titanium tetrachloride, are supported on various magnesium compounds. As a method for producing this catalyst, a known method is employed without any limitation. For example, JP-A-56-155206 and JP-A-56-1368.
06, ibid 57-34103, ibid 58-8706, ibid 58-83006, ibid 58-13
8708, 58-183709, 59-206408, 59-219311, 5958
60-81208, 60-81209, 60-186508, 60-19270
8, 61-211309, 61-271304, 62-15209, 62-
11706, 62-72702, 62-104810, etc. are adopted. Specifically, for example, a method in which titanium tetrachloride is co-ground with a magnesium compound such as magnesium chloride, a titanium halide and a magnesium compound in the presence of an electron donor such as alcohol, ether, ester, ketone or aldehyde. Examples thereof include a method of co-milling or a method of bringing a titanium halide, a magnesium compound and an electron donor into contact with each other in a solvent.

Next, as the organoaluminum compound [B], a compound known to be used for polymerization of olefin is adopted without any limitation. For example, trialkyl aluminums such as trimethyl aluminum, triethyl aluminum, tri-n propyl aluminum, tri-n butyl aluminum, tri-i butyl aluminum, tri-n hexyl aluminum, tri-n octyl aluminum, and tri-n decyl aluminum; Examples include diethyl aluminum monohalides such as diethyl aluminum monochloride; alkyl aluminum halides such as methyl aluminum sesquichloride, ethyl aluminum dichloride and ethyl aluminum dichloride. Alternatively, alkoxyaluminums such as monoethoxydiethylaluminum and diethoxymonoethylaluminum can be used. Of these, triethylaluminum is most preferable. The amount of organoaluminum compound used in each prepolymerization step is Al / Ti relative to the Ti atom in the titanium compound.
The (molar ratio) is 1 to 100, preferably 2 to 20.

Further, as the organosilicon compound [C], the compound represented by the general formula [I] is employed without any limitation. R and R'in the general formula [I] are hydrocarbon groups such as an alkyl group, an alkenyl group, an alkynyl group and an aryl group. Examples of the organosilicon compound suitably used in the present invention are as follows. For example, trimethylmethoxysilane, trimethylethoxysilane, dimethyldimethoxysilane, dimethylethoxysilane, diphenyldimethoxysilane, methylphenyldimethoxysilane, diphenyldiethoxysilane, ethyltrimethoxysilane, methyltrimethoxysilane, vinyltrimethoxysilane, Examples thereof include phenyltrimethoxysilane, methyltriethoxysilane, ethyltriethoxysilane, vinyltriethoxysilane, butyltriethoxysilane, phenyltriethoxysilane, ethyl silicate, and 6-triethoxysilyl 2-norbornene.

The amount of the organosilicon compound used in each prepolymerization step is 0.1 to 10 in terms of Si / Ti (molar ratio) with respect to the Ti atom of the titanium compound.
It is 0, preferably 0.5 to 10.

In the present invention, in addition to the above titanium compound [A], organoaluminum compound [B] and organosilicon compound [C], the following general formula [II] R ″ -I [II] It is preferable to use the iodine compound [D] represented by the above because the rigidity and heat resistance of the obtained polyolefin become high.

In the general formula [II], R ″ is a hydrocarbon group such as an alkyl group, an alkenyl group, an alkynyl group, or an aryl group. Specific examples of iodine compounds that can be preferably used in the present invention are as follows. For example, iodine, methyl iodide, ethyl iodide, propyl iodide, butyl iodide, iodobenzene, p-toluene iodide, etc. Among them, methyl iodide and ethyl iodide are preferable. The amount of the iodine compound used in (1) is 0.1 to 100, preferably 0.5 to 50 in terms of I / Ti (molar ratio) with respect to the titanium atom in the titanium compound.

In the present invention, prepolymerization is carried out in multiple stages, and different kinds of organosilicon compounds are used in each prepolymerization stage. In the present invention, the term "preliminary polymerization carried out in multiple steps" means that titanium obtained by prepolymerizing olefin in the presence of the above-mentioned components [A], [B], [C] and optionally [D]. Polyolefin containing and the above [B], [C]
Further, it means that the prepolymerization of olefin is further repeated in the presence of each component [D] optionally used. The prepolymerization is preferably performed in a range of 2 to 5 times. Each of the above-mentioned components used in each prepolymerization may be added sequentially or may be used as a mixture.

In each prepolymerization step, different types of organosilicon compounds are used. As the organosilicon compound, it is preferable to use a compound in which at least one of R and R'in the general formula [I] is a bulky hydrocarbon group such as a phenyl group, a cyclohexyl group or a norbornyl group. It is preferable because a hydrophilic polyolefin can be obtained. The order of use of the organosilicon compounds used in each prepolymerization step is not particularly limited.

In the prepolymerization of the present invention, the specific unsaturated compound is polymerized in at least one of the above prepolymerization steps. The unsaturated compound is represented by the following formula [A] or [B]
The compound shown by is used.

CH ₂ = CH-R ⁴ [B] Here, in the above formula [A], the alkyl group represented by R ¹ , R ² and R ³ is not particularly limited in the number of carbon atoms, but in order to improve the transparency of the obtained polypropylene,
It preferably has 1 to 6 carbon atoms.

Further, in the above formula [B], the alicyclic hydrocarbon group represented by R ⁴ may be either saturated or unsaturated, and
The number of carbon atoms is not particularly limited, but a 6-membered ring is preferable from the viewpoint of transparency of the obtained polypropylene. Specifically, a cyclohexyl group and 1-cyclohexene-1-
Group, 2-cyclohexen-1-yl group, 3-cyclohexen-1-yl group, 2-methyl-1-cyclohexen-1-yl group, 3-methyl-1-cyclohexene-1
-Yl group, 4-methyl-1-cyclohexen-1-yl group, 2-methyl-2-cyclohexen-1-yl group, 3
-Methyl-2-cyclohexen-1-yl group, 4-methyl-2-cyclohexen-1-yl group, 2-methyl-3
Examples thereof include a cyclohexen-1-yl group, a 3-methyl-3-cyclohexen-1-yl group, and a 4-methyl-3-cyclohexen-1-yl group.

Further, in the above formula [B], the aromatic hydrocarbon group represented by R ⁴ is an aryl group or an aralkyl group without any limitation. The aryl group preferably has 6 to 10 carbon atoms, specifically, a phenyl group, an o-tolyl group, a m-tolyl group, a p-tolyl group, a 2,3-xylyl group,
Examples thereof include a 2,4-xylyl group and a 4-t-butylphenyl group. The aralkyl group has 7 carbon atoms.
It is preferable that it is -11, specifically, a benzyl group,
Examples thereof include a phenethyl group, a phenylpropyl group and a phenylbutyl group.

The unsaturated compounds represented by the above formulas [A] and [B] are specifically shown as follows. For example, 3-methyl-
1-butene, 3-methyl-1-pentene, vinylcyclohexane, 4-vinylcyclohexene-1, styrene,
o-methylstyrene, pt-butylstyrene, allylbenzene, 1-vinyl-2-methylcyclohexene-1
And the like. Among them, 3-methyl-1-butene, 3-methyl-1-pentene, vinylcyclohexane, o-methylstyrene and pt-butylstyrene are particularly effective in improving the transparency of polypropylene. It is preferably used for

It is also possible to use two or more types of the above unsaturated compounds at the same time. Further, 10 parts by weight or less of α-olefin, for example, ethylene, propylene, butene, 1-hexene, 4-methyl-1-pentene and the like may coexist with the above unsaturated compound. Further, the prepolymerization may be carried out in the coexistence of hydrogen.

Of the multi-stage pre-polymerization stages in the present invention, olefins used in the pre-polymerization stages other than the stage using the above unsaturated compound include ethylene, propylene, and
-Butene, 1-hexene, 4-methyl-1-pentene, etc., and it is possible to use two or more types at the same time, but in consideration of improvement of stereoregularity, 90% mol or more of one specific type of olefin is considered. It is preferable to use.

The amount of polymerization performed in each pre-polymerization step depends on the titanium compound.
0.1 to 1000 g per 1 g, preferably 0.5 to 500 g may be selected. The ratio of the amount of polymerization at each stage is not particularly limited.

For each prepolymerization, it is usually preferable to apply slurry polymerization, and as a solvent, hexane, heptane, cyclohexane, benzene, or a saturated aliphatic hydrocarbon or aromatic hydrocarbon such as toluene alone or by using a mixed solvent thereof. You can Each prepolymerization temperature is -20 to 100
C., especially 0 to 60.degree. C., is preferred, and each stage of the prepolymerization may be carried out under different temperature conditions. The pre-polymerization time may be appropriately determined depending on the pre-polymerization temperature and the amount of polymerization in the pre-polymerization, and the pressure in the pre-polymerization is not limited, but in the case of slurry polymerization, it is generally atmospheric pressure to 5 kg / cm. It is about ² . Each prepolymerization may be carried out by any of batch, semi-batch and continuous methods. After the completion of each prepolymerization, it is preferable to wash saturated aliphatic hydrocarbons or aromatic hydrocarbons such as hexane, heptane, cyclohexane, benzene, and toluene alone or with a mixed solvent. Six times is preferable.

The polymerization conditions in the main polymerization after the preliminary polymerization according to the present invention are not particularly limited as long as the effects of the present invention can be recognized, but the following conditions are generally preferable. Polymerization temperature is 20 ~ 200
C., preferably 50 to 150.degree. C., and hydrogen can coexist as a molecular weight regulator. The polymerization can also be applied to slurry polymerization, solventless polymerization, and gas phase polymerization, and may be a batch type, a semi-batch type, or a continuous type, and the polymerization is performed in two or more stages under different conditions. You can also The olefins to be polymerized include ethylene, propylene, butene-1, pentene-1, hexene-1,4-methylpentene-1, etc. These monomers are used alone or in combination of two or more. be able to. When two or more kinds of olefins are used, it is preferable to use 90% by mol or more of a specific kind from the viewpoint of improving stereoregularity of the polyolefin. Further, ethers, amines, amides, sulfur-containing compounds, nitriles, carboxylic acids, acid amides, for controlling stereoregularity of olefins having 3 or more carbon atoms,
An electron donor such as an acid anhydride, an acid ester or an organic silicon compound can coexist. Of these, organosilicon compounds are preferable. As such an organosilicon compound, the one selected at the time of the above-mentioned prepolymerization can be used.

(Effects) According to the prepolymerization method of the present invention, it is possible to obtain a polyolefin having much more excellent transparency as compared with the conventional method of simply prepolymerizing branched α-olefin. Moreover, the polyolefin obtained by the method of the present invention has high stereoregularity and has excellent rigidity and heat resistance.

Therefore, the polyolefin obtained by the method of the present invention can be favorably used as a film as well as an injection molded article.

(Examples) Hereinafter, the present invention will be described with reference to Examples and Comparative Examples, but the present invention is not limited to these Examples.

The measuring method used in the following examples will be described.

(1) Stereoregularity The stereoregularity evaluation method used in the present invention is the following (a) and (b).

(A) p-Xylene Soluble Content 1 g of polymer was added to 100 cc of p-xylene, the temperature was raised to 120 ° C. with stirring, and stirring was continued for another 30 minutes to completely dissolve the polymer, and then the p-xylene solution was added. 23 ° C, 24
Left for hours. The precipitate was filtered off, and the p-xylene solution was completely concentrated to obtain a soluble component.

It is represented by room temperature p-xylene solubles (%) = (p-xylene solubles (g) / polymer 1g) × 100.

(B) ¹³ C-NMR pentad fraction A. Zambelli et al., Macromolecules 6,925 (1973)
Methods have been published in, i.e., a fraction bound to contiguous monomers five isotactic polymer molecular chain with ¹³ C-NMR.

The measurement was performed using JEOL GSX-270, with a pulse width of 90 °, a pulse interval of 15 seconds, and a total of 10,000 times. Peak attribution is Mac
Romolecules, 8, 697 (1975).

(2) Melt index (hereinafter abbreviated as MI) Complies with ASTM D-790.

(3) Flexural modulus (hereinafter abbreviated as Fm) Japan Steel Works J120SA II type injection molding machine 63.6mm × 1
A 2.7 mm × 0.31 mm test piece was prepared, and the test was performed according to ASTM: D-790.

(4) Heat distortion temperature (hereinafter abbreviated as HDT) Japan Steel Works J120SA II type injection molding machine 63.6mm × 1
A 2.7 mm × 0.31 mm test piece was prepared, and the test was performed according to ASTM: D-648.

(5) Transparency (haze value) It was measured according to JIS-K6714 48 hours after being molded into a plate of 80.0 × 50.0 × 1.0 (mm) at a resin temperature of 230 ° C. with a J120SA II type injection molding machine of Japan Steel Works.

(6) Molecular weight distribution (hereinafter abbreviated as w / n) The ratio of the weight average molecular weight (w) and the number average molecular weight (n) was measured by the GPC (gel permeation chromatography) method. Waters GPC-150 ° C
Performed at 135 ° C. using dichlorobenzene as a solvent.

(7) Crystallization temperature (hereinafter abbreviated as Tc) Samples were sampled at 230 ° C with a DSC-200 manufactured by Seiko Instruments Inc.
The temperature was maintained for 0 minutes, and the temperature was lowered at a speed of -40 ° C / minute for measurement.

(8) Melting point (hereinafter abbreviated as Tm) The sample is 1 at 230 ° C. by DSC-200 manufactured by Seiko Denshi Kogyo.
The temperature was maintained for 0 minutes, the temperature was lowered to 120 ° C., isothermal crystallization was performed at the same temperature for 10 minutes, the temperature was cooled to 50 ° C., and the temperature was raised at 10 ° C./minute for measurement.

Example 1 [Preparation of Titanium Compound] The titanium component was produced according to the method of Example 1 in JP-A-58-83006. That is, 0.95 g (10 mmol) of anhydrous magnesium chloride, 10 ml of decane, and 4.7 ml (30 ml) of 2-ethylhexyl alcohol were heated and stirred at 125 ° C. for 2 hours, and then 0.55 g (3.75 m) of phthalic anhydride was added to this solution.
mol) was added, and the mixture was further stirred and mixed at 125 ° C. for 1 hour to obtain a uniform solution. After cooling to room temperature, the whole amount was dropwise added to 40 ml (0.36 mol) of titanium tetrachloride kept at 120 ° C over 1 hour. After the completion of charging, the temperature of this mixed solution was raised to 110 ° C. over 2 hours, and when it reached 110 ° C., 0.54 ml (2.5 mol) of diisobutyl phthalate was added,
From this, the mixture was kept at the same temperature for 2 hours with stirring. After completion of the reaction for 2 hours, a solid part was collected by filtration, and 200 ml of this solid part was collected.
After resuspension of at TiCl _4, 2 hours, heating was performed reaction again 110 ° C.. After completion of the reaction, the solid portion was collected again by hot filtration, and washed thoroughly with decane and hexane until no free titanium compound was detected in the preliminary solution. The solid Ti catalyst component prepared by the above manufacturing method was held as a heptane slurry. The composition of the solid Ti catalyst component was 2.1% by weight, 57% by weight chlorine, 18.0% by weight magnesium, and 21.9% by weight diisobutyl phthalate.

[Preliminary polymerization]

Purified heptane in one autoclave with N ₂ substitution
200 ml, triethylaluminum 50 mmol, diphenyldimethoxysilane 10 mmol, ethyl iodide 50 mmol and solid Ti
After charging 5 mmol of the catalyst component in terms of Ti atom, propylene was continuously introduced into the reactor for 1 hour so that the amount of propylene was 3 g per 1 g of the solid Ti catalyst component, and the first preliminary polymerization was performed. The temperature during this period was kept at 15 ° C. After 1 hour, the introduction of propylene was stopped, and the inside of the reactor was sufficiently replaced with N ₂ . The solid portion of the resulting slurry was washed 6 times with purified heptane.

Furthermore, this solid component was charged into a N ₂ -substituted 1 autoclave, and 200 ml of purified heptane, 50 mmol of triethylaluminum, 10 mmol of 6-triethoxysilyl 2-norbornene and 50 mmol of ethyl iodide were added, and then 3-methyl 1 was added. -Butene (10 g) was charged, the reaction was carried out for 3 hours, and the second preliminary polymerization was carried out. The temperature during this period was kept at 15 ° C. Three
-Methyl-1-butene prepolymerization amount is 1 g of solid Ti catalyst component
It was 0.9 g per unit. The solid portion of the resulting slurry was washed 6 times with purified heptane.

(Conjugation)

Propylene 200 was charged into an autoclave with an internal volume of 400 that had been subjected to N ₂ substitution, and triethylaluminum 274 mm
ol, diphenyldimethoxysilane 274mmol, further hydrogen 2.0Nl
After charging, raise the internal temperature of the autoclave to 65 ° C,
The solid Ti catalyst component obtained through the above-mentioned prepolymerization step was charged with 1.1 mmol as a titanium atom. Then, the internal temperature of the autoclave was raised to 75 ° C., and propylene was polymerized for 3 hours. The polymerization pressure was 34 kg / cm ² , and the temperature during this period was kept at 75 ° C. and kept at 0.2 mol% while confirming the hydrogen concentration by gas chromatography. After 3 hours, unreacted propylene was purged to obtain a white granular polymer. The yield of the polymer was 52 kg, and the activity at this time was 20,800 g-pp / g-cat.
It was 3 hours. An antioxidant was added to the above polymer and mixed sufficiently, and then pelletized by a granulator. Table 1 shows the physical properties of the obtained polypropylene.

Example 2 In the first prepolymerization of Example 1, 6-triethoxysilyl-2- was used instead of diphenyldimethoxysilane.
With respect to norbornene, the same operation as in Example 1 was performed except that diphenyldimethoxysilane was used instead of 6-triethoxysilyl-2-norbornene in the second prepolymerization. The results are shown in Table 1.

Example 3 To the solid Ti catalyst component obtained by the prepolymerization of Example 1, 200 ml of heptane, 50 mmol of triethylaluminum, 10 mmol of phenyltriethoxysilane and 10 mmol of ethyl iodide were added, and then propylene was added again to 1 g of the solid Ti catalyst component. Against
It was introduced into the reactor for 1 hour so that the amount became 3 g, and the third prepolymerization was performed. The obtained solid component was washed 6 times with purified heptane. Polymerization was carried out in the same manner as in Example 1. The results are shown in Table 1.

Example 4 In the first prepolymerization of Example 1, 3-methyl-1-butene was used instead of propylene, and propylene was used instead of 3-methyl-1-butene in the second prepolymerization. Except for this, the same operation as in Example 1 was performed. The results are shown in Table 1.
It was shown to.

Example 5 Example 1 except that 3-methyl-1-butene was used in place of propylene in the first prepolymerization of Example 1.
The same operation was performed. The results are shown in Table 1.

Example 6 In the prepolymerization of Example 1, the same operation as in Example 1 was performed except that ethyl iodide was not used. The results are shown in Table 1.

Example 7 [Preparation of Titanium Compound] The titanium compound was prepared according to the method of Example 1 of JP-A-62-104810. That is, 100 g of aluminum trichloride (anhydrous) and 29 g of magnesium hydroxide were reacted while being pulverized at 25 ° C. for 3 hours in a vibration mill. After completion of heating, the mixture was cooled in nitrogen air to obtain a solid product (I).

In a glass flask, 15 ml of purified decane, 2.5 g of solid product (I), 8.5 g of n-butyl orthotitanate, 2-
Ethyl-1-hexanol 9.8g was mixed and stirred.
It was heated to 130 ° C. for 1.5 hours and dissolved to form a uniform solution. The solution is heated to 70 ° C., and 1.8 g of ethyl p-toluate is added to 1
After reacting for 2 hours, 2 g of 26 g of silicon tetrachloride was added with stirring.
The mixture was added dropwise over time to precipitate a solid, and the mixture was further stirred at 70 ° C. for 1 hour. The solid was separated from the solution and washed with purified hexane to obtain a solid product (II).

The total amount of this solid product (II) was 1,2-dichloroethane 30 m
Diisobutyl phthalate with l and 30 ml Titanium tetrachloride
After adding 1.5 g and reacting at 100 ° C. for 2 hours with stirring, the liquid phase part was removed by decantation at the same temperature,
30 ml of 1,2-dichloroethane, 30 ml of titanium tetrachloride and 1.5 g of diisobutyl phthalate were added again, the mixture was reacted at 100 ° C. for 2 hours while stirring, and then the solid portion was collected by hot filtration and washed with purified hexane, It was dried under reduced pressure at 25 ° C for 1 hour to obtain a solid product (III).

The solid product (III) is spherical and has an average particle size of 15 μm
The particle size distribution was extremely narrow. This solid product (III) was used as a solid Ti catalyst component.

The compositional analysis results of the solid Ti catalyst component are Ti3.0 wt% (hereinafter referred to as%), Cl56.2%, Mg17.6%, Al1.7.
%, Diisobutyl phthalate 20..1%, butoxy group 1.1%,
The content was 2-ethylhexyloxy group 0.2% and ethyl p-toluate 0.1%.

Thereafter, preliminary polymerization and main polymerization were carried out in the same manner as in Example 1.
The results are shown in Table 1.

Example 8 [Preparation of titanium compound] The titanium compound was prepared according to the method of Example 1 of JP-A-62-11706. That is, a glass three-necked flask (thermometer
To a stirrer), add 50 ml of purified heptane, 50 ml of titanium tetrabutoxide, 7.0 g of anhydrous magnesium chloride. Thereafter, the temperature of the flask was raised to 90 ° C., and magnesium chloride was completely dissolved over 2 hours. Next 40 flasks
Cool down to ℃, methylhydrogenpolysiloxane 10
By adding ml, magnesium chloride and a titanium tetrabutoxide complex were deposited. This was washed with purified heptane to give an off-white solid.

50 ml of a heptane slurry containing 10 g of the precipitated solid obtained above was introduced into a glass three-necked flask (with a thermometer and a stirrer) having an inner volume of 300 ml purged with nitrogen. Next, 20 ml of a heptane solution containing 5.8 ml of silicon tetrachloride was added over 30 minutes at room temperature, and further reacted at 30 ° C. for 45 minutes. 90 ° C
After reacting for 1.5 hours, the reaction mixture was washed with purified heptane after completion of the reaction. Next, 50 ml of a heptane solution containing 1.5 ml of diheptyl phthalate was added and reacted at 50 ° C. for 2 hours, followed by washing with purified heptane, and further adding 25 ml of titanium tetrachloride.
The reaction was performed at 90 ° C. for 2 hours. This was washed with purified heptane to obtain a solid Ti catalyst component. The titanium content in the solid Ti catalyst component was 3.04% by weight. Thereafter, preliminary polymerization and main polymerization were carried out in the same manner as in Example 1. The results are shown in Table 1.

Comparative Example 1 In the prepolymerization of Example 1, the same operation as in Example 1 was performed except that the second prepolymerization was not performed. The results are shown in Table 1.

Comparative Example 2 Similar to Example 1 except that 3-methyl-1-butene was used in place of propylene in the first prepolymerization of Example 1 and the second prepolymerization was not performed. The operation was performed. The results are shown in Table 1.

Comparative Example 3 In the second prepolymerization of Example 1, the same operation as in Example 1 was performed except that propylene-1 was used instead of 3-methylbutene-1. The results are shown in Table 1.

Comparative Example 4 The same operation as in Example 1 was performed except that diphenyldimethoxysilane was used instead of 6-triethoxysilyl-2-norbornene in the second prepolymerization of Example 1. The results are shown in Table 1.

Comparative Example 5 In the first stage of the prepolymerization of Example 1, 6-triethoxysilyl-2 was used instead of diphenyldimethoxysilane.
-The same operation as in Example 1 was performed except that norbornene was used.

Examples 9-12 In the second prepolymerization of Example 1, 3-methyl-1
-The same operation as in Example 1 was carried out except that the unsaturated compound shown in Table 2 was used instead of butene. The results are shown in Table 2.

Examples 13 to 15 In the prepolymerization of Example 1, 6-
The same operation as in Example 1 was performed except that phenyltriethoxysilane, methyltriethoxysilane, and methylphenyldiethoxysilane were used instead of triethoxysilyl-2-norbornene. The results are shown in Table 3.

[Brief description of drawings]

FIG. 1 is a flow chart of the olefin prepolymerization method of the present invention. However, * 1 and * 2 in the figure respectively represent the following. * 1: Preliminary polymerization is performed in multiple stages. However, in at least one stage of which, using an olefin represented by ^{_{CH 2 = CH-CR 1 R}} 2 R 3 or CH ₂ = CHR ^4. * 2: Different organosilicon compounds are used in each prepolymerization stage.

Claims (1)

(57) [Claims] 1. The following components A, B and C A. Titanium compound B. Organoaluminum compound C. General formula R _n Si (OR ') _4-n In the presence of an organosilicon compound represented by, olefins are preliminarily polymerized in multiple stages, different organosilicon compounds are used in each prepolymerization stage, and at least one stage of each prepolymerization stage is represented by the following formula: Or the following formula CH ₂ = CH-R ⁴ A method for prepolymerizing olefin, which comprises polymerizing an unsaturated compound represented by: