JPH07103173B2 - Method for producing atactic polypropylene - Google Patents

Description

FIELD OF THE INVENTION This invention relates to an improved process for making atactic polypropylene.

2. Description of the Related Art Conventionally, an olefin polymer is produced using a Ziegler catalyst, but the by-product atactic polyolefin, particularly atactic polypropylene (APP), has a number average molecular weight (Mn) of about 10,000. It was low and had little practical value.

In recent years, as a method for producing a high molecular weight APP, a method using a cyclopentanedienyl group-containing titanium compound and a catalyst containing aluminoxane as a main component (JP-A-60-245604) has been proposed. This method can produce a relatively high molecular weight APP having a number average molecular weight Mn of about 1 to 30 thousand in the room temperature range,
This molecular weight is not yet sufficient, and there is a drawback that the molecular weight of APP produced is lowered in the range of usual practical propylene polymerization temperature (50 to 90 ° C).

On the other hand, as a method for producing a high molecular weight elastic polypropylene having a number average molecular weight of Mn of 30 to 100,000, a method of using a catalyst in which a zirconium compound is supported on alumina is known (JP-A 61-179247), The molecular weight is too high and it is not suitable for applications such as films.

DISCLOSURE OF THE INVENTION Problems to be Solved by the Invention An object of the present invention is to produce a moderately high molecular weight atactic polypropylene useful as a transparent film having elasticity or a resin modifier, in a high yield.

Means for Solving the Problems As a result of intensive research to develop an atactic polypropylene having the above-mentioned preferable characteristics, the present inventors have developed a combination of a specific solid catalyst component and a specific external electron donor. The inventors have found that the above objects can be achieved, and have completed the present invention based on this finding.

That is, the present invention provides a solid catalyst component containing (A) magnesium, tetravalent titanium, halogen and an aromatic dicarboxylic acid diester as essential components, (B) an organoaluminum compound and (C) a formula. [R ¹ is an alkyl group having 1 to 20 carbon atoms, R ² is a hydrocarbon group having 1 to 10 carbon atoms, a hydroxyl group or a nitro group, m is an integer of 1 to 6,
n is an integer of 0 to (6-m)] is provided, and propylene is polymerized in the presence of a catalyst obtained from an alkoxy group-containing aromatic compound. It is a thing.

The solid catalyst component (A) used in the present invention is prepared by contacting a magnesium compound, a tetravalent titanium compound, a halogen or a halide and an aromatic dicarboxylic acid diester. The halogen or halide may not be used when the magnesium compound or the tetravalent titanium compound is the halide.

Examples of the magnesium compound include magnesium halide such as magnesium chloride, magnesium oxide, magnesium hydroxide, hydrotalcite, carboxylate of magnesium, alkoxy magnesium such as diethoxy magnesium, aryloxy magnesium, and alkoxy magnesium halide. , Alkylmagnesium halides such as allyloxymagnesium halides, ethylmagnesium magnesium, alkylmagnesium halides, and reaction products of other organomagnesium compounds with electron donors such as halosilanes, alkoxysilanes, silanols, and aluminum compounds.

Among these, magnesium halide, alkoxy magnesium, alkyl magnesium, and alkyl magnesium halide are preferable.

Examples of the tetravalent titanium compound which is one of the raw materials of the solid catalyst component (A) used in the present invention include, for example, tetramethoxytitanium, tetraethoxytitanium, tetra-n-propoxytitanium, tetraisopropoxytitanium and tetra-n-butoxy. Titanium, tetraisobutoxy titanium, tetracyclohexyl titanium, tetraphenoxy titanium and other formulas Ti
(OR) ₄ tetrahydrocarbyloxytitanium, titanium tetrahalide such as TiCl ₄ , TiBr ₄ , and TiI ₄ ,
(CH ₃ O) TiCl ₃ , (C ₂ H ₅ O) TiCl ₃ , (C ₃ H ₇ O) TiCl ₃ ,
_{(N-C 4 H 9 O} ) TiCl 3, (C 2 H 5 O) trihalide alkoxy titanium ₃ such _{TiBr, (CH 3 O) 2} TiCl 2, (C 2 H 5 O) 2 TiCl
_{2, (C 3 H 7 O} ) 2 TiCl 2, (n-C 4 H 9 O) 2 TiCl 2, (C 2 H 5 O)
₂ TiBr _{2 and} other dihalogenated alkoxy titanium, (CH ₃ O) ₃ T
_{iCl, (C 2 H 5 O} ) 3 TiCl, (C 3 H 7 O) 3 TiCl, (n-C 4 H 9 O)
Examples include monohalogenated alkoxy titanium such as ₃ TiCl.

These titanium compounds may be used alone or in combination of two or more.

Among these, high halogen content substances are preferable, and titanium tetrachloride is particularly preferable.

As the aromatic dicarboxylic acid diester which is one of the raw materials of the solid catalyst component (A) used in the present invention, dimethyl phthalate, diethyl phthalate, dipropyl phthalate,
Diisobutyl phthalate, methyl ethyl phthalate, methyl propyl phthalate, methyl isobutyl phthalate, ethyl propyl phthalate, ethyl isobutyl phthalate, propyl isobutyl phthalate, dimethyl terephthalate, diethyl terephthalate, dipropyl terephthalate, diisobutyl terephthalate, methyl ethyl terephthalate, methyl isobutyl terephthalate,
Ethyl propyl terephthalate, ethyl isobutyl terephthalate, propyl isobutyl terephthalate, dimethyl isophthalate, diethyl isophthalate, dipropyl isophthalate, diisobutyl isophthalate, methyl ethyl isophthalate, methyl propyl isophthalate, methyl isobutyl isophthalate, ethyl propyl isophthalate, ethyl Examples thereof include isobutyl isophthalate and propyl isobutyl isophthalate.

The aromatic dicarboxylic acid ester improves the catalytic activity and activity durability.

The following several examples can be given as specific methods for preparing the solid catalyst component (A) of the present invention.

(1) Prepared by pulverizing a magnesium compound or a complex compound of a magnesium compound and an aromatic dicarboxylic acid diester in the presence of an electron donor or a pulverization aid optionally added and reacting with a tetravalent titanium compound. .

(2) A liquid titanium compound having no reducing ability is reacted with a liquid tetravalent titanium compound in the presence of an aromatic dicarboxylic acid diester to precipitate a solid titanium complex.

(3) Prepared by reacting a tetravalent titanium compound with the product obtained in (1) or (2) above.

(4) An aromatic dicarboxylic acid diester and a tetravalent titanium compound are further reacted with the product obtained in the above (1) or (2) to prepare.

(5) A magnesium compound or a complex compound of a magnesium compound and an aromatic dicarboxylic acid diester is ground in the presence of a tetravalent titanium compound and an electron donor or a grinding aid optionally added, and treated with halogen or a halogen compound. And prepare.

(6) Prepared by treating the compound obtained in (1) to (4) above with halogen or a halogen compound.

In addition to these, JP-A-56-166205 and JP-A-57-63
309, JP-A-57-190004, JP-A-57-30040
The preparation methods described in JP-A No. 7-58370 and JP-A No. 58-47003 can also be used as the preparation method of the solid catalyst of the present invention.

Further, oxides of elements belonging to Groups II to IV of the periodic table, for example, oxides of silicon oxide, magnesium oxide, aluminum oxide, etc., or oxides or complex oxides of elements belonging to Groups II to IV of the periodic table, such as silica alumina. The solid substance supporting the magnesium compound, the aromatic dicarboxylic acid diester, and the tetravalent titanium halide are contacted in a solvent at a temperature of 0 to 200 ° C., preferably 10 to 150 ° C. for 2 minutes to 24 hours. Thus, the solid catalyst component can be prepared.

Further, in the preparation of the solid catalyst component (A), an organic solvent inert to magnesium compounds, aromatic dicarboxylic acid diesters and tetravalent titanium compounds as solvents, for example, aliphatic hydrocarbons such as hexane and heptane, benzene, Aromatic hydrocarbon such as toluene, or carbon number 1-12
Halogenated hydrocarbons such as halogenated compounds of saturated or unsaturated aliphatic, alicyclic or aromatic hydrocarbons can be used.

Regarding the composition ratio of the solid catalyst component (A) of the present invention thus obtained, the magnesium / titanium atomic ratio is 2
-100, the halogen / titanium atomic ratio is 5 to 200, and the aromatic dicarboxylic acid diester / titanium (molar ratio) is preferably 0.1 to 10.

The organoaluminum compound of the component (B) used in the catalyst of the present invention has a general formula AlR ³ _v X _3-v (wherein R ³ is an alkyl group having 1 to 10 carbon atoms, v is an integer of 1 to 3, X is Is a halogen atom such as chlorine and bromine), and as such,
Preferably, for example, trimethylaluminum, triethylaluminum, triisopropylaluminum, triisobutylaluminum, trialkylaluminum such as trioctylaluminum, diethylaluminium monochloride, diisopropylaluminium monochloride, diisobutylaluminum monochloride, dioctylaluminum monochloride, etc. Alkyl aluminum sesquihalides such as dialkylaluminum monohalide and ethylaluminum sesquichloride, and mixtures thereof can also be used.

The alkoxy-containing aromatic compound used as the component (C) of the catalyst of the present invention is represented by the above general formula (I), and for example, m
-Methoxytoluene, o-methoxyphenol, m-methoxyphenol, 2-methoxy-4-methylphenol, vinylanisole, p- (1-propenyl) anisole, p-allylanisole, 1,3-bis (p-methoxyphenyl) ) -1-Pentene, 5-allyl-2-methoxyphenol, 4-allyl-2-methoxyphenol,
Compounds containing monoalkoxy such as 4-hydroxy-3-methoxybenzyl alcohol, methoxybenzyl alcohol, nitroanisole and nitrophenetol, and o-
Dialkoxy-containing compounds such as dimethoxybenzene, m-dimethoxybenzene, p-dimethoxybenzene, 3,4-dimethoxytoluene, 2,6-dimethoxyphenol, 1-allyl-3,4-dimethoxybenzene, and 1,3,5 -Trimethoxybenzene, 5-allyl-1,2,3-trimethoxybenzene, 1,2,3-trimethoxy-5- (1-propenyl) benzene, 1,2,4-trimethoxy-5- (1-propenyl) ) Benzene, 1,2,3-trimethoxybenzene, 1,
A trialkoxy-containing compound such as 2,4-trimethoxybenzene can be used, and a dialkoxy-containing compound and a trialkoxy-containing compound are particularly preferable.

The amount of each component of the catalyst of the present invention used is such that the component (A) is converted to Ti atoms in an amount of 0.0005 to 1 mmol per reaction volume 1, and the component (B) is (B) / Ti. (Molar ratio) 1
It is used in an amount of up to 3000, preferably 40 to 800, and if it is out of this range, the catalytic activity becomes insufficient. The component (C) is
(C) / Ti (molar ratio) is 0.01 to 500, preferably 1 to 30
Used with 0. If it is less than 0.01, the molecular weight and selectivity of the polymer produced will decrease, and if it exceeds 500, the catalytic activity will decrease.

In carrying out the propylene polymerization reaction by the production method of the present invention, the above-mentioned catalyst component is added to the reaction system, and then propylene as a raw material is introduced into this system.

These three components (A), (B) and (C) can be mixed in predetermined amounts and brought into contact with each other, and then propylene can be immediately introduced to initiate polymerization, but after the contact, 0.2
It may be used after aging for 3 hours.

In the present invention, the polymerization form and conditions are not particularly limited, and any of solution polymerization, suspension polymerization, gas phase polymerization and the like are possible, and both continuous polymerization and discontinuous polymerization are possible. Particularly, solution continuous polymerization and suspension continuous polymerization are preferable in terms of efficiency and quality.

The propylene pressure of the polymerization reaction system of the present invention is 1 to 50 kg.
/ cm ² G, the reaction temperature can be appropriately selected within the range of 20 to 200 ° C, preferably 60 to 100 ° C. The molecular weight at the time of polymerization can be adjusted by a known means such as hydrogen. The reaction time is preferably selected within the range of 10 minutes to 10 hours.

EXAMPLES The present invention will be described in more detail with reference to examples.

Example 1 (1) Preparation of solid catalyst component 20 ml of purified heptane, 4 g of Mg (OEt) ₂ and 1.2 g of di-n-butyl phthalate were added to a 500 ml glass three-necked flask having an inner volume sufficiently replaced with nitrogen. It was The inside of the system maintaining 90 °, agitation of TiCl ₄ 110ml was added dropwise to TiCl ₄ in 5ml add-on while, reaction time of 2 hours the temperature was increased to 110 ° C.. The product obtained was then washed with 100 ml of purified heptane at 80 ° C. Next, 115 ml of TiCl ₄ was added and reacted at 110 ° C. for 2 hours. After completion of the reaction, the solid catalyst component was obtained by washing several times with 100 ml of purified heptane.

(2) Polymerization of Propylene 400 ml of purified heptane, 1 mmol of AlEt ₃ in the stainless steel autoclave of 1 and the amount of 1-allyl-3, shown in Table 1.
4-dimethoxybenzene (hereinafter abbreviated as ADMB) and 5 mg of the solid catalyst component shown in (1) above were added, and the total pressure was 8 kg / c.
Polymerization of propylene was carried out at m ² and 70 ° C. for 2 hours. The results are shown in the table.

Examples 2 to 7 and Comparative Examples 1 and 2 Example 1 was repeated except that the conditions shown in the table were changed.

In Comparative Example 1, the polymer yield was low, the proportion of the hot heptane-soluble portion was small, and the intrinsic viscosity (molecular weight) was also small.

Comparative Example 3 (1) Preparation of solid catalyst component In a device similar to that of Example 1, 150 ml of purified heptane and 10 g of purified heptane were added.
Mg (OEt) _{2 of} was added and stirred.

Next, at room temperature, 2.08 g of carbon tetrachloride and 1.32 g of tetraisopropoxy titanium were added and the reaction was carried out at 80 ° C. for 2 hours. The reaction product obtained was then washed with 150 ml of purified heptane at room temperature.

Then add 3.69 g of n-butyl benzoate and 50 ml of TiCl ₄
The temperature was raised to 98 ° C. and the reaction was carried out for 1 hour. Then at room temperature
It was washed with 150 ml of purified heptane, 50 ml of TiCl ₄ was further added, the temperature was raised to 98 ° C., and the reaction was carried out for 0.5 hour. After completion of the reaction, the solid catalyst component was obtained by washing with 100 ml of purified heptane several times.

(2) Polymerization of propylene The same procedure as in Example 1 was performed.

Example 8 (1) Preparation of solid catalyst component To a glass three-necked flask having a nitrogen content of 300 ml and having a volume of 300 ml, purified heptane (75 ml), titanium tetrabutoxide (75 ml) and anhydrous magnesium chloride (10 g) were added, and the flask was heated to 90 ° C. The mixture was heated to completely dissolve magnesium chloride for 2 hours. Next, the flask is cooled to 40 ° C., and 15 ml of methylhydrogenpolysiloxane is added to precipitate a magnesium chloride / titanium butoxide complex. After washing it with purified heptane, add 8.7 ml of silicon tetrachloride and 1.8 ml of diheptyl phthalate and add 50
Hold at 2 ° C for 2 hours. Then washed with purified heptane,
Further, 25 ml of titanium tetrachloride is added and the mixture is kept at 70 ° C for 2 hours. This is washed with purified heptane to give a solid catalyst component (A).
Got

The titanium content in this component (A) was 3.0% by weight, and the diheptyl phthalate content was 25% by weight.

(2) Polymerization of propylene The same procedure as in Example 1 was performed.

Comparative Example 4 In Example 1, TiCl ₄ 0.25 m was used instead of the solid catalyst component.
The same procedure was performed except that mol was used.

EFFECTS OF THE INVENTION According to the method of the present invention, the production ratio of isotactic polypropylene having stereoregularity can be significantly reduced, and the molecular weight of the product can be significantly increased. The remarkable effect is that a moderately high molecular weight atactic polypropylene of about 10,000 to 200,000 can be produced in a high yield.

Further, it can be widely used as a high molecular weight atactic polypropylene obtained by the method of the present invention, a transparent elastic film and a polymer modifier, and is useful.

[Brief description of drawings]

 The drawing is a flow chart of the manufacturing method of the present invention.

Claims (1)

[Claims] 1. A solid catalyst component containing (A) magnesium, tetravalent titanium, halogen and an aromatic dicarboxylic acid diester as essential components, (B) an organoaluminum compound and (C) formula. [R ¹ is an alkyl group having 1 to 20 carbon atoms, R ² is a hydrocarbon group having 1 to 10 carbon atoms, a hydroxyl group or a nitro group, m is an integer of 1 to 6,
n is an integer of 0- (6-m)], The propylene is polymerized in the presence of a catalyst obtained from the alkoxy group-containing aromatic compound represented by the formula.