JP3207464B2 - Method for producing propylene polymer - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[Background of the Invention]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a propylene polymer having excellent crystallinity.

[0002]

2. Description of the Related Art A propylene polymer is a resin having high rigidity and high mechanical strength, but higher rigidity is required for some applications. Also, propylene polymer,
Since the crystallization speed is relatively slow, there is a problem that relatively large spherulites are generated and the transparency is not sufficient.

In order to improve the rigidity and transparency of polypropylene, many attempts have been made to improve the polymerization catalyst and to improve the crystallinity by prepolymerization. For example, JP
Nos. 0-139731, JP-A-61-151204 and JP-A-61-155404 disclose a branched α.
It has been shown that the prepolymerization of the olefin increases the crystallinity of the polypropylene in the subsequent main polymerization.

[0004]

Although these techniques are useful, the stiffness and transparency of the resulting product are not yet sufficient depending on the application.

[0005]

[Means for Solving the Problems]

[Summary of the Invention] <Summary> The present invention provides a highly stereoregular catalyst containing a specific organosilicon compound in advance to convert a specific monomer (specifically, a branched α-olefin) into a specific organoaluminum compound. After pre-polymerization underneath, propylene homopolymerization or copolymerization of propylene and other α-olefins is performed to efficiently produce extremely rigid and highly transparent polypropylene. .

That is, the process for producing a propylene polymer according to the present invention comprises the steps of preparing titanium, magnesium and halogen, and the following formula [I] R ¹ R ² _3- nSi (OR ³ ) _n [I] (where R ¹ is An organosilicon compound represented by a branched hydrocarbon residue, R ² and R ³ each independently represent a branched or linear hydrocarbon residue, and n represents a number satisfying 2 ≦ n ≦ 3. Of propylene or copolymerization of propylene with another α-olefin in the presence of a catalyst formed from a solid titanium catalyst component (A) and an organoaluminum compound (B) containing as essential components In the method, the solid titanium catalyst component (A) is a compound having a branched α-chain formed on an organoaluminum compound having at least one hydrocarbon residue having 3 to 10 carbon atoms directly bonded to an aluminum atom. Olefins that are contacted are those subjected to prepolymerization step consists in solid titanium catalyst component (A) 1 g per 0.1~1000g polymerization, characterized in.

<Effect> According to the present invention, polypropylene having extremely high rigidity and high transparency can be efficiently produced. In general, the organoaluminum compound having a hydrocarbon residue having 3 to 10 carbon atoms used in the present invention is considered to cause a decrease in stereoregularity and activity as compared with an organoaluminum compound having 2 carbon atoms, particularly triethylaluminum. It was customary not to use it for a magnesium-supported solid catalyst.

However, when the organoaluminum compound having a hydrocarbon residue having 3 to 10 carbon atoms is used for polymerizing a branched α-olefin with a solid catalyst containing a specific organosilicon compound, the above-mentioned organoaluminum compound has the above-mentioned properties. Not only is there no problem, but it should have been unexpectedly useful in the production of high rigidity, high transparency polypropylene.

[Specific description of the invention] <Catalyst component> The catalyst used in the present invention is formed from the component (A) and the component (B), and falls under the category of a so-called Ziegler type catalyst. Things. Here, "formed from component (A) and component (B)" includes a third component which does not unduly impair the effects of the present invention or more preferably a third component which advantageously acts on the present invention. It should be understood that this does not exclude the case.

<Solid Titanium Catalyst Component (Component (A))>
Component (A) is a solid component containing titanium, magnesium, halogen, and an organosilicon compound represented by the following formula [I] as essential components. R ¹ R ² _3- nSi (OR ³ ) _n [I] (where R ¹ is a branched hydrocarbon residue, and R ² and R ³ are each independently a branched or straight hydrocarbon residue. And n represents a number satisfying 2 ≦ n ≦ 3.)

Here, "containing as essential components" means that in addition to the essential four components listed, other suitable elements may be included as optional components, and each of these elements is a total. It indicates that it may be present as any desired compound, and that these elements may be present as mutually bonded.

The magnesium compound used as a magnesium source in the present invention includes magnesium halide, dialkoxymagnesium, alkoxymagnesium halide, magnesium oxyhalide, dialkylmagnesium, magnesium oxide, magnesium hydroxide, magnesium carboxylate and the like. No. Preferred among these are magnesium halides.

The titanium compound serving as a titanium source may be a compound of the general formula Ti (OR ⁴ ) _4-m X _m (where R ⁴ is a hydrocarbon residue, preferably having about 1 to 10 carbon atoms). And X represents a halogen, and m represents a number satisfying 0 ≦ m ≦ 4.). As a specific example, TiCl ₄ , TiBr ₄ , Ti (OC ₂ H ₅ ) C
l ₃ , Ti (OC ₂ H ₅ ) ₂ Cl ₂ , Ti (OC
_{2 H 5) 3 Cl, Ti} (O-iC 3 H 7) Cl 3, Ti
(O-nC ₄ H ₉ ) Cl ₃ , Ti (O-nC ₄ H ₉ ) ₂
Cl ₂ , Ti (OC ₂ H ₅ ) Br ₃ , Ti (OC
_{2 H 5) (C 4 H} 9) 2 Cl, Ti (O-nC 4 H 9)
₃ Cl, Ti (O-nC ₆ H ₅ ) Cl ₃ , Ti (O-i
C ₄ H ₉ ) ₂ Cl ₂ , Ti (OC ₅ H ₁₁ ) Cl ₃ , Ti
(OC ₆ H ₁₃ ) Cl ₃ , Ti (OC ₂ H ₅ ) ₄ , Ti
_{(O-nC 3 H 7)} 4, Ti (O-nC 4 H 9) 4, T
_{i (O-iC 4 H 9} ) 4, Ti (O-nC 6 H 13) 4,
Ti (O-nC ₈ H ₁₇ ) ₄ , Ti [OCH ₂ CH (C ₂
H ₅ ) C ₄ H ₉ ] _{4 and the} like.

A molecular compound obtained by reacting an electron-donating compound with TiX ′ ₄ (where X ′ represents a halogen) can also be used. As a specific example, TiCl ₄
CH ₃ COC ₂ H ₅ , TiCl ₄ CH ₃ CO ₂ C ₂
H ₅ , TiCl ₄ .C ₆ H ₅ NO ₂ , TiCl ₄ .CH
₃ COCl, TiCl ₄ .C ₆ H ₅ COCl, TiCl
_{4 · C 6 H 5 CO 2} C 2 H 5, TiCl 4 · ClCOC
_{2 H 5, TiCl 4 · C} 4 H 4 O and the like. Among the above titanium compounds, preferred are TiCl ₄ and Ti
_{(O-nC 4} H _{9) 4.}

The halogen source is usually supplied from the above-mentioned halogen compounds of magnesium and / or titanium, but may be obtained from a known halogenating agent such as a halide of aluminum, a halide of silicon, or a halide of phosphorus. It can also be supplied.

The halogen contained in the catalyst component is fluorine,
It may be chlorine, bromine, iodine or a mixture thereof, with chlorine being particularly preferred.

As the organosilicon compound, the following formula [I]
The compound represented by these is mentioned. R ¹ R ² _3- nSi (OR ³ ) _n [I] (where R ¹ is a branched hydrocarbon residue, and R ² and R ³ are each independently a branched or straight hydrocarbon residue. And n represents a number satisfying 2 ≦ n ≦ 3.)

R ¹ is a branched hydrocarbon residue having about 3 to 10 carbon atoms, and the “branch” occurs at the carbon bonded to the silicon atom, ie, at the α-carbon atom. It is preferred that the α-carbon atom is a secondary or tertiary carbon atom, especially a tertiary carbon atom. R ² and R ³ each preferably have about 1 to 10 carbon atoms.

Specific examples of the organosilicon compound used in the present invention are as follows. (CH ₃ ) ₃ CSi
(CH ₃ ) (OCH ₃ ) ₂ , (CH ₃ ) ₃ CSi (CH
(CH ₃ ) ₂ ) (OCH ₃ ) ₂ , (CH ₃ ) ₃ CSi
(CH ₃ ) (OC ₂ H ₅ ) ₂ , (C ₂ H ₅ ) ₃ CSi
(CH ₃ ) (OCH ₃ ) ₂ , ((CH ₃ ) ₂ CH) ₂ S
i (OCH ₃ ) ₂ , (CH ₃ ) (C ₂ H ₅ ) CHSi
(CH ₃ ) (OCH ₃ ) ₂ , ((CH ₃ ) ₂ CHC
_{H 2) 2 Si (OCH 3} ) 2, (C 2 H 5) (CH 3)
₂ CSi (CH ₃ ) (OCH ₃ ) ₂ , (C ₂ H ₅ ) (C
H ₃ ) ₂ CSi (CH ₃ ) (OC ₂ H ₅ ) ₂ , (C
H ₃ ) ₃ CSi (OCH ₃ ) ₃ , (CH ₃ ) ₃ CSi
(OC ₂ H ₅ ) ₃ , (C ₂ H ₅ ) ₃ CSi (OC
_{2 H 5) 3, (CH} 3) 2 (C 2 H 5) CHSi (OC
H ₃ ) ₃ , (C ₂ H ₅ ) (CH ₃ ) ₂ CSi (OC ₂ H
₅ ) ₃ . These organosilicon compounds can be used alone or in combination of two or more.

The amount of the titanium compound used is 1 × 10 ^-4 to 1 in molar ratio with respect to the amount of the magnesium compound used.
000, preferably 0.01 to 10. When a compound for that purpose is used as a halogen source, the amount used is 1 × 10 5 in molar ratio with respect to the amount of magnesium used irrespective of whether the titanium compound and / or the magnesium compound contains halogen or not. The range is preferably from ^{-4 to} 1,000, and more preferably from 0.1 to 100.

The amount of the silicon, aluminum and phosphorus compounds to be used is preferably in the range of 1 × 10 ^{-3 to} 100, more preferably 0.01 to 1, in terms of molar ratio with respect to the above-mentioned magnesium compound. It is. The amount of the organosilicon compound used is preferably in the range of 1 × 10 ⁻³ to 10 and more preferably in the range of 0.01 to 5 in a molar ratio to the amount of the above-mentioned magnesium compound.

The solid catalyst component for a Ziegler catalyst containing "halogen, magnesium and halogen" as an essential component, which has been proposed by the present inventors, has further used a specific silicon compound as an essential component in the present invention. (A).

Therefore, the component (A) in the present invention can be specified in an appropriate process or at a suitable time in the following method, for example, which is suitable for the production of "a solid catalyst component for a Ziegler catalyst containing titanium, magnesium and halogen as essential components". Can be produced by adding or presenting a silicon compound of

(A) A method of contacting a magnesium halide with an electron-donating compound and a titanium-containing compound as required.

(B) A method in which alumina or magnesia is treated with a phosphorus halide compound and brought into contact with a magnesium halide, an electron-donating compound, or a titanium halide-containing compound.

(C) A method of contacting a titanium halide compound and / or a silicon halide compound with a solid component obtained by contacting a magnesium halide with a titanium tetraalkoxide and a specific polymer silicon compound. As the polymer silicon compound, a compound represented by the following formula is suitable. (Where R ⁵ is a hydrocarbon residue having about 1 to 10 carbon atoms,
p indicates a degree of polymerization such that the viscosity of the polymer silicon compound becomes about 1 to 100 centistokes. )

More specifically, methyl hydrogen polysiloxane, ethyl hydrogen polysiloxane, phenyl hydrogen polysiloxane, cyclohexyl hydrogen polysiloxane, 1,3,5,7-tetramethylcyclotetrasiloxane, 1,3 5,7,9-
Pentamethylcyclopentasiloxane is preferred.

(D) dissolving a magnesium compound with titanium tetraalkoxide and an electron donating compound,
A method in which a titanium compound is brought into contact with a solid component precipitated with a halogenating agent or a titanium halide compound.

(E) A method in which an organomagnesium compound such as a Grignard reagent is allowed to act with a halogenating agent, a reducing agent, and the like, and then contacted with an electron-donating compound and a titanium compound as required.

(F) A method of contacting an alkoxymagnesium compound with a halogenating agent and / or a titanium compound in the presence or absence of an electron-donating compound. Among the methods for producing the component (A), (A) and (C) are preferable.

As the component (A) used in the present invention, the solid component obtained as described above can be used as it is, or the solid component is brought into contact with an olefin in the presence of an organoaluminum compound to obtain the present invention. May be obtained by arbitrarily performing pre-polymerization in a stage before subjecting to the pre-polymerization step (details described later).

When the component (A) has been subjected to prepolymerization, the polymerization conditions for the prepolymerization of olefins for producing the component (A) are not particularly limited. The following conditions are preferred. The polymerization temperature is from 0 to 8
0 ° C, preferably 10 to 60 ° C. The polymerization amount is preferably from 0.001 to 50 g of olefins per gram of the solid component, and more preferably from 0.1 to 10 g of olefins.

[0033]

[0034]

<Component (B)> The component (B) is an organoaluminum compound. Specific examples, ^{R 6} _3-q AlX q
Or R ⁷ _3-r Al (OR ⁸ ) _r (where R ⁶ and R ⁷
Is a hydrocarbon residue or a hydrogen atom having about 1 to 20, preferably 2 to 6 carbon atoms, which may be the same or different, R ⁸ is a hydrocarbon residue, X is a halogen, q and r are each 0
≦ q <3, 0 <r <3. ) Something is represented. Specifically, (a) trialkylaluminums such as trimethylaluminum, triethylaluminum, triisobutylaluminum, trihexylaluminum, trioctylaluminum, tridecylaluminum and the like; (b) alkylaluminum halides such as diethylaluminum monochloride, diisobutyl (C) alkyl hydrides such as diethyl aluminum hydride and diisobutyl aluminum hydride; and (d) aluminum alkoxides such as diethyl aluminum ethoxide and diethyl aluminum phenoxide such as aluminum monochloride, ethyl aluminum sesquichloride and ethyl aluminum dichloride. .

[0036] These (a) to other organometallic compound with an organoaluminum compound (d), for example ^{R 9} _3-s Al
(OR ¹⁰ ) _s (where 1 ≦ s ≦ 3, R ⁹ and R
¹⁰ is a hydrocarbon residue having about 1 to 20 carbon atoms which may be the same or different). For example, a combination of triethylaluminum and diethylaluminum ethoxide, a combination of diethylaluminum chloride and diethylaluminum ethoxide, a combination of ethylaluminum dichloride and diethylaluminum ethoxide, a combination of triethylaluminum and diethylaluminum ethoxide and diethylaluminum chloride Is mentioned.

<Production of Propylene Polymer> The process for producing a propylene polymer according to the present invention comprises a prepolymerization step of polymerizing a branched α-olefin and a homopolymerization of propylene or a copolymerization of propylene with another α-olefin. It is a two-step process including a main polymerization step for performing polymerization.

<Preliminary Polymerization Step> The preliminary polymerization step is a step of polymerizing 0.1 to 1000 g of the branched α-olefin per 1 g of the solid titanium catalyst component (A). One of the features is that the organoaluminum compound used in this step is a specific one. In this step, preferably 0.1 to 50 g, more preferably 1 to 20 g, of a branched α-olefin is polymerized per 1 g of the solid titanium catalyst component (A). The polymerization amount is 0.1 g per 1 g of solid titanium catalyst.
If the amount is less than the above, the effect of improving the rigidity of the product is insufficient.

The organoaluminum compound which forms a catalyst system by being combined with the component (A) in this prepolymerization step is an organoaluminum compound having at least one hydrocarbon residue having 3 to 10 carbon atoms directly bonded to an aluminum atom. It is.

As a specific example, R ¹¹ _3-t AlX _t or R ¹² _3-u Al (OR ¹³ ) _u (where R ¹¹ and R ¹² may be the same or different and have 3 to 10 carbon atoms) A hydrogen residue or a hydrogen atom (however, not all R ¹¹ or R ¹² are hydrogen atoms at the same time), R ¹³ is a hydrocarbon residue,
X is halogen, t and u are respectively 0 ≦ t <3, 0 <
u <3. ). Specifically, (a) trialkylaluminum, for example, triisobutylaluminum, trinormalbutylaluminum, trihexylaluminum, trioctylaluminum, etc., and (b) alkylaluminum halide, for example, diisobutylaluminum monochloride, dinormalbutylaluminum monochloride And (d) alkyl hydrides such as diisobutylaluminum hydride, and (d) aluminum alkoxides such as diisobutylaluminum ethoxide and diisobutylaluminum phenoiside.

These organoaluminum compounds (a) to (d) can be used alone or in combination of two or more. Among them, preferred are organoaluminum compounds having a branched or cyclic hydrocarbon residue, and particularly preferred are triisobutylaluminum and diisobutylaluminum chloride.

The use ratio of the organoaluminum compound to the component (A) can be varied over a wide range, but from the viewpoint of maintaining the catalytic activity and improving the rigidity improving effect, 0.5 to 0.5% of titanium atoms in the component (A) is required. 100 (molar ratio), preferably 1-2
A ratio of 0 (molar ratio), more preferably 1 to 5 (molar ratio), is appropriate.

The branched α-olefin has 5 to 1 carbon atoms.
0 is preferred, and particularly preferred is one in which the position of the branch is at a carbon atom adjacent to the carbon atom having a double bond.
Specific examples of such a branched α-olefin are as shown below.

3-methyl-1-butene, 3-methyl-1
-Pentene, 4-methyl-1-pentene, 4,4-dimethyl-1-pentene, 4-methyl-1-hexene, 4-
Ethyl-1-hexene and the like can be exemplified. Most preferred of these is 3-methyl-1-butene. These can be used alone or as a mixture of two or more as needed.

This step can be performed in the presence or absence of an inert solvent. When an inert solvent is used, known hydrocarbon solvents such as hexane and heptane can be used. The reaction temperature is 0 to 100 ° C, preferably 2 to 100 ° C.
0-80 ° C. The reaction pressure is preferably normal pressure to 50 atm, more preferably normal pressure to 10 atm. This step can be performed by any of a continuous method and a batch method.

<Main Polymerization Step> In the main polymerization step, the catalyst component (A) subjected to the above-mentioned branched α-olefin prepolymerization was used.
(And an organoaluminum compound) in which propylene homopolymerization or copolymerization of propylene with another α-olefin is carried out in the presence of a polymer produced by preliminary polymerization. In the main polymerization step, the total polymerization amount of 9
It is usual to obtain a polymer of 5% or more (the remainder being the polymer from the prepolymerization step).

The catalyst in the main polymerization step is formed from the component (A) and the component (B), and the contents thereof are as described above. The component (B) which is an organoaluminum compound can be used after being supplied to the preliminary polymerization step, or can be newly supplied to the main polymerization step.

Other olefins for the copolymerization of propylene include olefins having about 2 to 6 carbon atoms, such as ethylene, butene-1, and hexene-1. Therefore, in the present polymerization, polymers having various structures such as a propylene homopolymer, a random copolymer of propylene and ethylene, butene-1 or hexene-1, or a block copolymer of propylene and ethylene are produced. be able to.

As the polymerization mode, slurry polymerization performed in an inert solvent, liquid phase bulk polymerization performed in a propylene solvent, gas phase polymerization performed in a gaseous propylene atmosphere, and the like are used. The polymerization pressure is from normal pressure to 100 atm, preferably from normal pressure to
40 atm, and the polymerization temperature is 30 to 90 ° C, preferably 50 to 80 ° C. This step can be preferably performed by either a continuous method or a batch method. In addition, hydrogen can be used as a molecular weight regulator. The following examples further illustrate the invention (therefore, the invention is not limited thereto).

[0050]

【Example】

<Example 1> Preparation of component (A) n was dehydrated and deoxygenated in a flask sufficiently purged with nitrogen.
-200 ml of heptane are introduced and then MgC
l ₂ 0.4 moles and _{Ti (O-nC 4 H 9} ) 4 was 0.8 mol introduced and reacted for 2 hours at 95 ° C.. After completion of the reaction, the temperature was lowered to 40 ° C, and then methylhydrodiene polysiloxane (of 20 centistokes) was added for 48 hours.
Milliliter was introduced and reacted for 3 hours. The resulting solid component was washed with n-heptane.

Then, 50 ml of purified n-heptane was introduced into a flask sufficiently purged with nitrogen, and 0.24 mol of the solid component synthesized as described above was introduced in terms of Mg atoms. Next, 25 ml of n-heptane was added to SiCl _4.
0.4 mol was mixed and introduced into the flask at 30 ° C. for 60 minutes, and reacted at 90 ° C. for 3 hours.

Further, 0.016 mol of phthalic acid chloride was mixed with 25 ml of n-heptane, and
The mixture was introduced into the flask at 30 ° C for 30 minutes and reacted at 90 ° C for 1 hour. After the completion of the reaction, the resultant was washed with n-heptane. Then, 0.24 mmol of SiCl ₄ was introduced thereto, and 10
The reaction was performed at 0 ° C. for 3 hours. After the completion of the reaction, the resultant was sufficiently washed with n-heptane.

Into a flask sufficiently purged with nitrogen, 50 ml of sufficiently purified n-heptane was introduced, then 5 g of the solid component obtained above was introduced, and further, (CH ₃ ) ₃
0.81 ml of CSi (CH ₃ ) (OCH ₃ ) ₂ was introduced and contacted at 30 ° C. for 2 hours. N- after contact
Washed thoroughly with heptane.

[0054] Prepolymerization 1-liter stirring-type autoclave refined heptane 500 ml, by introducing the solid catalyst 8g and diisobutylaluminum chloride 0.75g, prepared by the, by introducing more 3-methyl-1-butene 50 g,
The reaction was performed at 40 ° C. for 6 hours. Thereafter, washing was performed with purified heptane. The polymerization amount of 3-methyl-1-butene was 4.5 g / g of the solid catalyst.

[0055] After the Main Polymerization volume of 200 liter stirring-type autoclave was sufficiently replaced with propylene, sufficiently dehydrated n- heptane 6
3 liters were introduced, and 16 g of triethylaluminum and 3 g of the solid catalyst were introduced at 75 ° C. under a propylene atmosphere. Polymerization was carried out by introducing propylene at a rate of 9 kg / HR for 4 hours while adjusting the hydrogen concentration in the gas phase to 0.3 vol%. Thereafter, 100 ml of butanol was added to terminate the polymerization, the remaining monomer was discharged out of the system, filtered and dried to obtain 36.1 kg of polypropylene powder. The polymerization results and the quality evaluation results were as shown in Table 2. The production of the films for evaluating the film quality shown in Table 2 was performed as follows.

Production of Film 2,6-Particulate was added as an antioxidant to 100 parts by weight of the polymerization powder.
Add 0.10 parts by weight of di-t-butyl-p-cresol, 0.02 parts by weight of Irganox 1010 and 0.05 parts by weight of calcium stearate as a chlorine scavenger, mix with a super mixer, and pelletize with an extruder did.

The pellets were formed into a sheet-like film using an extruder, and sequentially stretched 5 times in the longitudinal direction and 10 times in the transverse direction to finally obtain a stretched film having a thickness of 30 μm. One surface of the stretched film was subjected to corona discharge treatment. The haze, LSI and Young's modulus of this film were measured.

Each physical property in Table 2 was measured according to the following method. MFR: ASTM-D-1238 Haze: ASTM-D-1003 LSI: Measured by an LSI tester manufactured by Toyo Seiki. Flexural modulus: ASTM-D-790

<Comparative Example 1> A similar experiment was performed as in Example 1, except that the step of prepolymerization was omitted. The polymerization results and the quality evaluation results are as shown in Table 2. The crystallinity of the product is significantly lower than that of Example 1.

<Comparative Example 2> A similar experiment was conducted except that triethylaluminum was used in place of diisobutylaluminum chloride in the prepolymerization step of Example 1. The polymerization results and the quality evaluation results are as shown in Table 2. Also in this case, the crystallinity of the product was determined in Example 1.
It is significantly lower than that of

Comparative Example 3 Preparation of Solid Catalyst Component 75 ml of purified heptane, 7 ml, was placed in a 500 ml glass three-necked flask (with a thermometer and a stirring bar), which had been purged with nitrogen.
5 ml of titanium tetrabutoxide and 10 g of anhydrous magnesium chloride are added. Thereafter, the temperature of the flask is raised to 90 ° C., and magnesium chloride is completely dissolved over 2 hours. Next, the flask was cooled to 40 ° C. and 15 ml of methylhydrogenpolysiloxane was added,
Deposit magnesium chloride / titanium tetrabutoxide complex. This was washed with purified heptane, and 8.7 ml of silicon tetrachloride and 2.0 g of phthalic acid chloride were added thereto.
Hold for 2 hours at ° C. After this, it is washed with purified heptane,
Further, 25 ml of titanium tetrachloride is added, and the mixture is kept at 25 ° C. for 2 hours. This was washed with purified heptane to obtain a solid catalyst component. The titanium content in the solid catalyst component was 2.7% by weight.

[0062] Prepolymerization 1-liter stirring-type autoclave refined heptane 500 ml, the solid catalyst 8g was adjusted by the, by introducing triisobutylaluminum 8g addition of 3-methyl-1-butene 110g, 3 hours at 50 ° C. I let it. Thereafter, washing was performed with purified heptane. 3-methyl-1
-Butene polymerization amount was 12.9 g / g of solid catalyst.

[0063] After the Main Polymerization volume of 200 liter stirring-type autoclave was sufficiently replaced with propylene, sufficiently dehydrated n- heptane 6
3 liters were introduced and triethylaluminum 16 g,
6.4 g of diphenyldimethoxysilane and 3 g of the solid catalyst were introduced at 75 ° C. under a propylene atmosphere. Polymerization was carried out by introducing propylene at a rate of 9 kg / HR for 4 hours while adjusting the hydrogen concentration in the gas phase to 0.3 vol%. Thereafter, 100 ml of butanol was added to terminate the polymerization, the remaining monomer was discharged out of the system, filtered and dried to obtain 33.6 kg of polypropylene powder. The polymerization results and the quality evaluation results were as shown in Table 2.

<Examples 2 and 3> Preliminary polymerization of 3-methyl-1-butene was carried out using the solid catalyst component prepared as in Example 1 and diisobutylaluminum chloride in the ratios shown in Table 1. The polymerization results and the quality evaluation results were as shown in Table 2.

_{Table 1} Solid catalyst DIBAC ^{* 1} 3-MeBu-1 ^{* 2} Prepolymerization amount (g) (g) (g) (g-pp / g-solid catalyst ) Example 2 8.0 0.75 15 1.52 Example 3 8.0 0.75 120 13.2 * 1 DIBAC: diisobutylaluminum chloride * 2 3-MeBu-1: 3-methyl-1-butene

Example 4 In the prepolymerization, diisobutylaluminum chloride was changed to triisobutylaluminum, and tert-butylmethyldimethoxysilane was replaced with 1.
The same experiment as in Example 1 was performed except that 6 g was added. The polymerization results and the quality evaluation results were as shown in Table 2.

_{Table 2} Polymer Results Quality Evaluation Result _{Catalyst Yield Poly 3-MFR Density Flexural Modulus Haze LSI} (g-pp / g-MeBu-1 (g / 10 ₂ ^{Solid Catalyst) Content (ppm) Minutes) (g / cc) (kg / cm) (%) (%)} Example 1 12,030 370 2.1 0.9116 15,200 0.4 1.2 Example 2 13,800 110 2.0 0.9113 14,800 0.5 1.4 Example 3 12,600 1050 2.1 0.9116 15,300 0.4 1.2 Example 4 11,600 1010 1.8 0.9 115 15,000 0.4 1.3 Comparative Example 1 10,410-1.9 0.9082 10,800 0.6 5.0 Comparative Example 2 6,410 290 2.1 0.9097 11,900 0.6 2.3 Comparative Example 3 11,200 1150 1.8 0.9101 13,700 0.5 1.8

[0068]

As described above, according to the present invention, polypropylene having extremely high rigidity and high transparency can be efficiently produced.

[Brief description of the drawings]

FIG. 1 is to assist in understanding the technical contents of the present invention relating to a Ziegler catalyst.

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int. Cl. ⁷ , DB name) C08F 10/06 C08F 4/658 CA, REGISTRY (STN)

Claims (1)

(57) [Claims] 1. A titanium, magnesium and halogen as well as the following formula (I) _{^{R 1 R 2 3-n Si}} (OR 3) n (I) (wherein, ^{R 1} is a branched hydrocarbon residue, ^{R 2} And R ³ each independently represent a branched or linear hydrocarbon residue, and n represents a number satisfying 2 ≦ n ≦ 3.) A solid titanium catalyst component containing, as an essential component, an organosilicon compound represented by the formula: (A) in the presence of a catalyst formed from an organoaluminum compound (B), in the method of homopolymerizing propylene or copolymerizing propylene with another α-olefin, the solid titanium catalyst component (A ) Is brought into contact with a branched α-olefin to an organoaluminum compound having at least one of a hydrocarbon residue having 3 to 10 carbon atoms directly bonded to an aluminum atom to obtain a solid titanium catalyst component (A) Characterized in that it is in this specification are used in the preliminary polymerization step, which consists in g per 0.1~1000g polymerization method for producing a propylene polymer.