JP3160944B2 - Method for producing low crystalline polypropylene - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to a method for producing a low-crystalline polypropylene.

[0002]

2. Description of the Related Art Conventionally, as a method for producing an olefin polymer, a catalyst mainly comprising a combination of a transition metal compound of Group IV to VI and an organic metal compound of Group I to III in the periodic table. Systems (so-called Ziegler-Natta catalysts) are known to be effective. When polypropylene is industrially produced, a titanium trichloride composition or a catalyst system in which titanium tetrachloride is supported on various compound carriers is mainly used.

Hitherto, crystalline polypropylene having a sufficiently restricted stereoregularity, that is, isotactic polypropylene, has been industrially produced and used in various industrial fields. Amorphous polypropylene, that is, atactic polypropylene, has been treated as an unnecessary by-product, but has recently been used in the field of, for example, adhesive materials. On the other hand, low crystalline polypropylene having an intermediate stereoregularity has characteristics such as flexibility and excellent transparency and impact resistance as compared with ordinary polypropylene, and by utilizing these characteristics, ordinary polypropylene is used. Different applications from crystalline polypropylene are used in each field,
For example, it can be expected in the fields of films, sheets, injection molding and the like.

[0004] These production methods include, for example, hexane,
Examples thereof include a so-called slurry polymerization method using a hydrocarbon solvent such as heptane, a so-called bulk polymerization method using liquefied propylene as a solvent, and a so-called gas-phase polymerization method in which polymerization is performed in gas-phase propylene. However, in the production of low-crystalline polypropylene, when a slurry polymerization method or a bulk polymerization method is employed, a part or most of the low-crystalline polypropylene is dissolved in a solvent, which is extremely difficult in production. On the other hand, when the gas-phase polymerization method is adopted, a very difficult problem in production, such as dissolution of a part or most of the low-crystallinity polypropylene in a solvent, is solved. There arises a problem that it becomes tacky and it becomes difficult to transport the polypropylene powder.

On the other hand, conventionally obtained low-crystal polypropylene (for example, low-crystal polypropylene produced by using a catalyst described in JP-B-42-10610, JP-B-53-46799) is boiling. Production of a low-crystalline polypropylene having a relatively high n-heptane-insoluble portion and insufficient flexibility, transparency, and impact resistance of the obtained molded article, and thus easily having desired flexibility and the like. The law is eagerly needed.

[0006] In view of the above problems of the prior art, the present inventors have conducted intensive studies to find a method for producing these solved low crystallinity polypropylenes. As a result, the following [A] specific solid titanium catalyst component and [B] organoaluminum compound catalyst component, and further specific [C] organoboron silicon compound catalyst component and [D] organosilicon compound catalyst component in a specific molar ratio. The inventors have found that low-crystalline polypropylene of the desired quality can be produced by polymerizing propylene using the combined catalyst, and have reached the present invention. As is apparent from the above description, an object of the present invention is to provide a vapor-phase polymerization method in which low-crystallinity polypropylene powder does not have an adhesive property capable of sticking to each other, and the polypropylene powder has excellent fluidity and transportability, and is bulky. Without lowering the density, without deteriorating the productivity even in the conventional crystalline polypropylene gas-phase polymerization production equipment, with the desired flexibility, excellent transparency, low-crystalline polypropylene having excellent impact resistance Is to provide a way to gain.

[0007]

The present invention has the following configuration (1). (1) [A] a solid titanium catalyst component containing magnesium, titanium, halogen and a polycarboxylic acid ester as essential components formed by contacting a magnesium compound, a titanium compound and a polycarboxylic acid ester, [B] an organic compound aluminum compound catalyst component, [C] the general formula ^{_{(R 1 3 SiO) 3 B}} [I] an organosilicon boron compound catalyst component (wherein R ¹ is. indicating a hydrocarbon group) represented by, [D] the general formula R ² _X R ³ _Y Si (OR ⁴ ) _Z [II] (wherein R ² and R ⁴ are hydrocarbon groups, R ³ is a hydrocarbon group or a hydrocarbon group containing a hetero atom, and X + Y + Z =
4,0 ≦ X ≦ 2,1 ≦ Y ≦ 3,1 ≦ Z ≦ 3), and an organosilicon compound catalyst component [D] and an organosilicon boron compound catalyst component [ Low-crystalline polypropylene characterized in that propylene is polymerized in gas-phase propylene using a catalyst system having a molar ratio to C] ([D] / [C] molar ratio) of 0.001 to 1000. Manufacturing method.

The titanium catalyst component [A] used in the present invention comprises:
It is a highly active catalyst component containing magnesium, titanium, halogen and polycarboxylic acid ester as essential components. A method for producing such a titanium catalyst component [A] is described in, for example, JP-A-50-108385 and 50-1265.
No. 90, No. 51-20297, No. 51-28189
Nos. 51-64586, 51-92885, 51-136625, 52-87489, and 52
No. 100576, No. 52-147688, No. 52-
No. 104593, No. 53-2580, No. 53-400
No. 93, No. 53-40094, No. 55-135102
Nos. 55-135103 and 55-152710
Nos. 56-811, 56-11908, 56
No.-18606, No.58-83006, No.58-13
8705, 58-138706 and 58-138
No. 707, No. 58-138708, No. 58-1387
09, 58-138710, 58-13871
No. 5, No. 60-23404, No. 61-21109,
Nos. 61-37802, 61-37803, 62
-104810, 62-104811, 62-
No. 104812, No. 62-104813, No. 63-5
It can be manufactured according to the method disclosed in each gazette such as 4405.

Specific examples of the polyvalent carboxylic acid used in the solid titanium catalyst component [A] include esters of phthalic acid, maleic acid, substituted malonic acid and the like and alcohols having 2 or more carbon atoms. In the present invention, there are various magnesium compounds used for the solid titanium catalyst component [A], but magnesium compounds having or not having a reducing ability are used. Examples of the former include dimethyl magnesium, diethyl magnesium, dipropyl magnesium, dibutyl magnesium, ethyl magnesium chloride, propyl magnesium chloride, butyl magnesium chloride and the like. Examples of the latter include magnesium chloride, magnesium bromide, magnesium halides such as magnesium iodide, methoxy magnesium chloride, alkoxy magnesium chloride such as ethoxy magnesium chloride, ethoxy magnesium, isopropoxy magnesium, and butoxy magnesium. Examples include magnesium carboxylate such as alkoxymagnesium, magnesium laurate, and magnesium stearate. Among these, particularly preferred compounds are magnesium halide, alkoxymagnesium chloride and alkoxymagnesium.

In the present invention, the solid titanium catalyst component [A]
Ti (OR) is usually used as a titanium compound for
_A X _4-A (R is a hydrocarbon group, X is a halogen, 0 ≦ A ≦
The compound represented by 4) is optimal. Specifically, Ti
Titanium tetrahalide such as Cl ₄ , TiBr ₄ , T
_{i (OCH 3) Cl 3,} Ti (OC 2 H 5) trihalide, alkoxy titanium such as Cl _3, Ti (OCH ₃₎
Dialkoxytitanium dihalide such as ₂ Cl ₂ , Ti (OC ₂ H ₅ ) ₂ Cl ₂ , Ti (OCH ₃ ) ₃ Cl, T
monohalogenated trialkoxy titanium such as i (OC ₂ H ₅ ) ₃ Cl, Ti (OCH ₃ ) ₄ , Ti (OC ₂ H
_{5) 4} is a tetraalkoxy titanium such as, especially preferred is TiCl _4. In the preparation of the titanium catalyst component [A], in addition to the above-mentioned titanium compound, magnesium compound and polycarboxylic acid ester, if necessary, other electron donors such as alcohol, ether, phenol,
A silicon compound, an aluminum compound, and the like can coexist.

[0011] As the organoaluminum compound catalyst component used in the present invention [B], the general formula AlR ⁵ _M R
⁶ _N X _{3- (M + N)} (wherein, R ⁵ and R ⁶ represent a hydrocarbon group or an alkoxy group, X represents a halogen, and M and N represent any number of O <M + N ≦ 3. ) Can be used. Specific examples include trimethylaluminum, triethylaluminum, tri-n-propylaluminum, tri-n-butylaluminum, trii-butylaluminum, diethylaluminum chloride, di-n-propylaluminum monochloride, diethylaluminum iodide, methylaluminum sesquichloride , Ethyl aluminum sesquichloride, ethoxy diethyl aluminum and the like. These organoaluminum compounds can be used alone or in combination of two or more.

[0012] general formula organosilicon boron compound catalyst component [C] used in the present invention (R ¹ ₃ SiO)
_An organosilicon boron compound represented by 3B [I] (wherein R ¹ represents a hydrocarbon group) is used. Specific examples thereof include tris (trimethylsiloxy) borane, tris (triethylsiloxy) borane, tris (tri-n-propylsiloxy) borane, tris (tri-n-butylsiloxy) borane, tris (tri-n-pentylsiloxy) borane, Tris (tri-n-hexylsiloxy) borane, tris (tri-n-heptylsiloxy) borane, tris (tri-i-propylsiloxy) borane, tris (tri-i-butylsiloxy) borane and the like can be exemplified.

[0013] Formula ^{_{R 2 X R 3 Y Si (}} OR as organosilicon compound catalyst component [D] used in the present invention
⁴ ) _Z [II] (wherein R ² and R ⁴ represent a hydrocarbon group, R ³ represents a hydrocarbon group or a hydrocarbon group containing a hetero atom,
X + Y + Z = 4, 0 ≦ X ≦ 2, 1 ≦ Y ≦ 3, 1 ≦ Z ≦ 3
Can be used.
Specific examples include methyltrimethoxysilane, methyltriethoxysilane, methyltripropoxysilane, ethyltrimethoxysilane, ethyltriethoxysilane,
Ethyltripropoxysilane, n-propyltrimethoxysilane, n-propyltriethoxysilane, i-propyltrimethoxysilane, i-propyltriethoxysilane, n-butyltrimethoxysilane, n-butyltriethoxysilane, i-butyl Trimethoxysilane, i-
Butyltriethoxysilane, t-butyltrimethoxysilane, t-butyltriethoxysilane, n-pentyltrimethoxysilane, n-pentyltriethoxysilane,
Neopentyltrimethoxysilane, neopentyltriethoxysilane, hexadecyltrimethoxysilane, hexadecyltriethoxysilane, dimethyldimethoxysilane, dimethyldiethoxysilane, diethyldimethoxysilane, diethyldiethoxysilane, di-n-propyldimethoxysilane, di i-propyldimethoxysilane, din
-Butyldimethoxysilane, dii-butyldimethoxysilane, di-t-butyldimethoxysilane, di-n-pentyldimethoxysilane, dineopentyldimethoxysilane,
Phenyltrimethoxysilane, phenyltriethoxysilane, diphenyldimethoxysilane, diphenyldiethoxysilane, cyclohexyltrimethoxysilane, cyclohexyltriethoxysilane, dicyclohexyldimethoxysilane, dicyclohexyldiethoxysilane, 3
-Mercaptopropylmethyldimethoxysilane, 3-isocyanatopropyltriethoxysilane, 2- (3-cyclohexenyl) ethyltrimethoxysilane, and the like. These organosilicon compounds can be used alone or as a mixture of two or more kinds at an arbitrary ratio.

The organoaluminum compound catalyst component [B] and the organosilicon boron compound catalyst component [C] used in the present invention may be premixed before being subjected to polymerization, or may be subjected to heat treatment after mixing. it can. Also, the organoaluminum compound catalyst component [B]
The catalyst component [D] and the organosilicon compound catalyst component [D] may be mixed in advance before being subjected to polymerization, or may be subjected to heat treatment after mixing. In addition, an organoaluminum compound catalyst component [B], an organosilicon boron compound catalyst component [C], and an organosilicon compound catalyst component [D] which are previously mixed before being subjected to polymerization or heat-treated after mixing are used. You can also. Here, the term "heat treatment" means that a mixture obtained by mixing the catalyst components in a container purged with an inert gas is subjected to a heat treatment in a temperature range of 25 ° C to 100 ° C for 10 minutes to 48 hours.

[0015] The polymerization reaction is carried out in gas-phase propylene.
The polymerization temperature is about 20 to 150 ° C and the pressure is 2 to 5
It is preferable to carry out the reaction under the condition of about 0 kgf / cm ² G. It is also possible to use hydrogen or the like as a molecular weight regulator. The amount of the organoaluminum compound catalyst component [B] used is about 1 to 600 moles in terms of aluminum atoms in the component [B] per mole of titanium atoms in the solid titanium catalyst component [A]. The organosilicon boron compound catalyst component [C] is preferably used in an amount of 0.2 to 200 moles in terms of boron atoms in the component [C] with respect to 1 mole of titanium atoms in the component [A]. It is prepared so that the molar ratio between the organosilicon compound catalyst component [D] and the component [C] is 0.001 to 1000, preferably 0.01 to 100.

The analysis and measurement methods of various physical properties according to the examples described later are shown below. (1) Melt flow rate (MFR) Based on JIS K6758. (2) Boiling n-heptane soluble part A soluble part when extracted with boiling n-heptane for 6 hours using a Kumagawa extractor. (3) Flexural modulus and flexural strength Based on JIS K7203. (4) Tensile strength Based on JIS K7113. (5) Heat deformation temperature (HDT) Based on JIS K7207. (6) Izod impact strength Based on JIS K7110. (7) Haze 1 mm thick, based on JIS K7015. (8) IR-τ A film having a thickness of about 40 µ was heat-treated at 135 ° C for 1 hour, and the absorbance was measured with an infrared spectrophotometer to obtain 997 cm
^-1 and the absorbance ratio at 973 cm ^-1 (A997 / A9
73) was used as the IR-τ value. (9) Catalyst efficiency Total amount of polypropylene produced per gram of solid titanium catalyst component [A] (g) (10) Bulk specific gravity (BD) Weight of polypropylene (g) per unit volume (ml) (11) ) Flowability of polypropylene powder Vitreous funnel (similar to commercial funnel, outlet diameter about 2c)
Using m), visual observation was performed according to the following procedure. (A) Cover the outlet of the funnel with a partition plate, and add about 200 g of polypropylene powder to the funnel. (B) Remove the partition plate covering the funnel outlet. (B) Visual observation of the discharge status of the polypropylene powder. Good flowability (O): Discharge state equivalent or almost equivalent to crystalline polypropylene. Poor flowability (x): A discharge situation in which the polypropylene powder cannot be discharged or cannot be discharged in the middle of discharge, or the discharge is slower than the discharge of crystalline polypropylene. Hereinafter, the present invention will be described with reference to examples, but the present invention is not limited thereto without departing from the gist of the invention.

Example 1 (Preparation of Catalyst-Preparation of Solid Titanium Catalyst Component) A mixture of 150 g of magnesium ethoxide, 275 ml of 2-ethylhexyl alcohol and 300 ml of toluene was placed under a carbon dioxide atmosphere of ² kgf / cm ² G. 3 at 93 ° C
After stirring for an hour, a further 400 ml of toluene and 400 ml
ml of n-decane was added. Hereinafter, this solution is referred to as a magnesium carbonate solution. 100 ml of toluene, 30 ml
Chlorobenzene, 9 ml of tetraethoxysilane,
8.5 ml of titanium tetrachloride and 100 ml of Isopar G (isoparaffinic hydrocarbon having an average carbon number of 10 and a boiling point of 156 to 176 ° C.) were stirred at 30 ° C. for 5 minutes, and 50 ml of the magnesium carbonate solution was added. After stirring for 5 minutes, 22 ml of tetrahydrofuran was added,
Stirred at 60 ° C. for 1 hour. After stopping the stirring and removing the supernatant, the generated solid was washed with 50 ml of toluene. 100 ml of chlorobenzene and 100 ml of the obtained solid
Was added and stirred at 135 ° C. for 1 hour. After stirring was stopped and the supernatant was removed, 250 ml of chlorobenzene, 100 ml of titanium tetrachloride and 2.1 ml of di-n-butyl phthalate were added, followed by stirring at 135 ° C. for 1.5 hours. After removing the supernatant, 600 ml of toluene, 800 ml
The solid was washed sequentially with 1 ml of Isopearl G and 400 ml of hexane to collect a solid titanium catalyst component. The composition of this solid titanium catalyst component was 2.3% by weight of titanium, 55% by weight of chlorine, 17% by weight of magnesium, and 7.5% by weight of di-n-butyl phthalate.

(Polymerization) 30 g of MF was placed in a horizontal polymerization vessel (L / D = 3) equipped with a 3-liter inner volume stirrer and purged with nitrogen.
A polypropylene powder of R2.5 g / 10 min was charged, 0.007 mmol of solid titanium catalyst component, 1.4 mmol of triethylaluminum, 0.105 mmol of tris (trimethylsiloxy) borane and 0.105 mmol of diisopropyldimethoxysilane in terms of titanium atom. 035 mmol, then 50 mmol of hydrogen, and then propylene, 22 kgf / cm ²
G, gas phase polymerization was performed for 2 hours. After extracting the polymer so that 30 g of the polypropylene powder remained in the polymerization vessel, the same amount of each component as above was charged, and gas phase polymerization was repeated under the same polymerization conditions as above (second polymerization). Such an operation was further repeated four times (the third to sixth polymerizations). The polymer obtained at the sixth time had a bulk specific gravity of 0.46 g / ml, an MFR of 2.4 g / 10 min, a boiling n-heptane soluble portion of 12.1% by weight, an IR-τ of 0.893, and a bend. Elastic modulus is 10100kg
f / cm ² , flexural strength 271 kgf / cm ² , tensile strength 288
kgf / cm ² , heat distortion temperature of 96 ° C., Izod impact strength of 7.3 kgf · cm / cm, haze of 60% and catalyst efficiency of 217
It was 00 g-pp / g-cat.

Example 2 The amount of tris (trimethylsiloxy) borane used in Example 1 was 0.14 mmol, the amount of diisopropyldimethoxysilane was 0.007 mmol, and the amount of hydrogen was 45 mm.
Gas phase polymerization was carried out in the same manner as in Example 1 except that ol was used. The polymer obtained in the sixth time had a bulk specific gravity of 0.45 g /
ml, MFR 2.5 g / 10 min, boiling n-heptane soluble part 19.7 wt%, IR-τ 0.803, flexural modulus 6900 kgf / cm ² , flexural strength 198 kgf / cm ² , The tensile strength was 220 kgf / cm ² , the heat distortion temperature was 83 ° C., the Izod impact strength was 12.3 kgf · cm / cm, the haze was 41%, and the catalyst efficiency was 22,400 g-pp / g-cat.

Example 3 Before charging the triethylaluminum, tris (trimethylsiloxy) borane and diisopropyldimethoxysilane used in Example 2, they were mixed in a vessel which had been previously purged with nitrogen, and heated (at 45 ° C. for 4 hours). ), And gas phase polymerization was carried out in the same manner as in Example 2 except that the amount of hydrogen was changed to 35 mmol. The polymer obtained in the sixth time had a bulk specific gravity of 0.45 g / ml, an MFR of 2.6 g / 10 min, a boiling n-heptane soluble part of 22.8% by weight, an IR-τ of 0.801, Flexural modulus 6400 kgf / cm ² , Flexural strength 187 kgf / cm ² , Tensile strength 211 kgf / cm ² , Thermal deformation temperature 79 ° C, Izod impact strength 12.8 kgf · cm / c
m, haze is 40% and catalyst efficiency is 21200g-pp / g-cat
Met.

Comparative Example 1 A gas phase polymerization was carried out in the same manner as in Example 1 except that the diisopropyldimethoxysilane used in Example 2 was not used. The polymer obtained in the sixth time had a bulk specific gravity of 0.1.
39 g / ml, MFR 2.8 g / 10 min, boiling n-heptane soluble part 34.2 wt%, IR-τ 0.799, flexural modulus 6000 kgf / cm ² , flexural strength 180 kgf / cm ² ,
Tensile strength: 203 kgf / cm ² , heat distortion temperature: 77 ° C., Izod impact strength: 12.7 kgf · cm / cm, haze: 43%
And the catalyst efficiency was 20400 g-pp / g-cat.

Comparative Example 2 The same procedure as in Example 1 was carried out except that the tris (trimethylsiloxy) borane used in Example 1 was not used, the amount of diisopropyldimethoxysilane used was changed to 0.14 mmol, and the amount of hydrogen was changed to 70 mmol. Gas phase polymerization was performed by the method. 6
The polymer obtained in the second round had a bulk specific gravity of 0.46 g / ml and MF
R: 2.5 g / 10 min, boiling n-heptane soluble part: 2.2% by weight, IR-τ: 0.958, flexural modulus: 16500
kgf / cm ^2, bending strength 441kgf / cm ^2, tensile strength 39
5 kgf / cm ² , heat deformation temperature of 120 ° C., Izod impact strength of 4.4 kgf · cm / cm, haze of 73% and catalyst efficiency of 1
It was 7000 g-pp / g-cat.

Example 4 The amount of tris (trimethylsiloxy) borane used in Example 1 was changed to 0.014 mmol, instead of diisopropyldimethoxysilane, 0.14 mmol of hexadecyltriethoxysilane and 35 mmol of hydrogen were used. Except for the above, gas-phase polymerization was performed in the same manner as in Example 1. The polymer obtained in the sixth time had a bulk specific gravity of 0.46 g / ml, an MFR of 2.6 g / 10 min, a boiling n-heptane soluble portion of 14.7% by weight, an IR-τ of 0.891, Flexural modulus 9600kgf /
cm ² , flexural strength 263 kgf / cm ² , tensile strength 278 kg
f / cm ² , heat deformation temperature: 95 ° C., Izod impact strength: 8.8 kgf · cm / cm, haze: 52%, catalyst efficiency: 143
It was 00 g-pp / g-cat.

Example 5 A gas phase polymerization was carried out in the same manner as in Example 4 except that hexadecyltriethoxysilane used in Example 4 was changed to isocyanatopropyltriethoxysilane and the amount of hydrogen was changed to 40 mmol. The polymer obtained in the sixth time had a bulk specific gravity of 0.45 g / ml, an MFR of 2.3 g / 10 min, a boiling n-heptane soluble portion of 10.8% by weight, an IR-τ of 0.878,
Flexural modulus 10100kgf / cm ² , Flexural strength 267kg
f / cm ² , tensile strength 283 kgf / cm ² , heat deformation temperature 96
° C, Izod impact strength was 7.9 kgf · cm / cm 2, haze was 59%, and catalyst efficiency was 16700 g-pp / g-cat.

Example 6 A gas phase polymerization was carried out in the same manner as in Example 2 except that tris (trimethylsiloxy) borane used in Example 2 was replaced with tris (triethylsiloxy) borane.
The polymer obtained at the sixth time had a bulk specific gravity of 0.45 g / ml,
17. FR of 2.1 g / 10 min, boiling n-heptane soluble part is 18.
3% by weight, IR-τ 0.809, flexural modulus 700
0 kgf / cm ² , bending strength 201 kgf / cm ² , tensile strength 2
23 kgf / cm ² , heat deformation temperature was 83 ° C., Izod impact strength was 11.5 kgf · cm / cm 2, haze was 41%, and catalyst efficiency was 19400 g-pp / g-cat. Example 1 shown above
Tables 1 and 2 show the physical property values of the polypropylenes obtained in Comparative Examples 1 to 6 and Comparative Examples 1 and 2.

[0026]

[Table 1]

[Table 2]

[Brief description of the drawings]

FIG. 1 is a flowchart showing a manufacturing method according to the present invention.

Claims (3)

(57) [Claims] 1. [A] a solid titanium catalyst component comprising magnesium, titanium, halogen and a polycarboxylic acid ester as essential components formed by contacting a magnesium compound, a titanium compound and a polycarboxylic acid ester, [B] ] an organoaluminum compound catalyst component, [C] the general formula ^{_{(R 1 3 SiO) 3 B}} [I] an organosilicon boron compound catalyst component (wherein ^{R 1} is. indicating a hydrocarbon group) represented by, [D] general Formula R ² _X R ³ _Y Si (OR ⁴ ) _Z [II] (wherein R ² and R ⁴ represent a hydrocarbon group, R ³ represents a hydrocarbon group or a hydrocarbon group containing a hetero atom, and X + Y + Z =
4,0 ≦ X ≦ 2,1 ≦ Y ≦ 3,1 ≦ Z ≦ 3), and an organosilicon compound catalyst component [D] and an organosilicon boron compound catalyst component [ Low-crystalline polypropylene characterized in that propylene is polymerized in gas-phase propylene using a catalyst system having a molar ratio to C] ([D] / [C] molar ratio) of 0.001 to 1000. Manufacturing method. 2. Forming a solid titanium catalyst component [A].
Magnesium compound used for
Nesium, alkoxy magnesium chloride or alcohol
One or more compounds selected from the group consisting of
The titanium compound has the general formula Ti (OR)_AX_4-a  (R is a hydrocarbon group, X is a halogen, 0 ≦ A ≦ 4)
Phthalic acid, maleic acid
Or one or more polycarboxylic acids selected from substituted malonic acids
The production method according to claim 1, wherein the alcohol ester is 3. An organoaluminum compound component [B] having the general formula A1R⁵ _MR⁶ _NX_{3- (M + N)}  (Where R⁵And R⁶Represents a hydrocarbon group or an alkoxy group
X represents a halogen, and M and N represent 0 <M + N ≦
(Indicating an arbitrary number of 3).
2. The production method according to 1.