JPH0543621A - Production of propylene polymer - Google Patents

Abstract

PURPOSE:To produce a flexible propylene polymer. CONSTITUTION:Propylene is polymerized in the presence of a catalyst system comprising an organoaluminum compd. component and a solid catalyst component which is obtd. by reacting a carrier with a titanium tetrahalide, then with a phthalic ester, and again with the titanium tetrahalide. The carrier is obtd. by reacting an aluminum halide, a silicon compd., and a magnesium compd. Thus, a proylene polymer is prepd. which is almost odorless and gives a clear molded article having a reduced surface stickiness.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a soft propylene polymer having a proportion of insoluble matter in boiling n-heptane of 10 to 80%. In particular, the present invention relates to a method for producing a soft propylene polymer having a molded product with low tackiness and good film transparency.

[0002]

2. Description of the Related Art A soft propylene polymer has a content of insoluble matter in boiling n-heptane of 90% or more, compared with a conventional isotactic propylene polymer.
It has excellent characteristics such as flexibility, impact resistance and transparency. Therefore, the flexible propylene polymer can be expected to be used in fields such as films and sheets different from the isotactic propylene polymer. Up to now, after polymerizing propylene, without performing post-treatment such as extraction of low molecular weight components, when molding a soft propylene polymer as it is,
There is a problem that the molded product has surface tackiness. The surface tack of molded articles depends on the content of amorphous, low molecular weight moieties, which are soluble, for example, in boiling methyl acetate. It is important that this boiling methyl acetate solubles is less.

In order to solve the above problems, a method has been proposed in which a low-molecular-weight adhesive component is separated from a propylene polymer and a non-adhesive component is blended to obtain a soft propylene polymer having no adhesive property. However, this method complicates the process. Conventionally, as a catalyst system for producing a soft propylene polymer, for example, titanium tetrachloride or titanium trichloride and trialkylaluminum (Japanese Patent Publication No. 32-10596), titanium trihalide and titanium alkoxide and alkyl groups are used. Aluminum compounds (Japanese Patent Publication No. 42-10610), supported catalysts using magnesium or manganese compounds as carriers, and organic aluminum compounds (Japanese Patent Publication No. 53-46799).
JP-A-47-9342, JP-A-59-19740
No. 9 and JP-A No. 60-235812) are disclosed.

Among the above catalyst systems, a catalyst system comprising a combination of a solid catalyst component in which a transition metal compound such as titanium is supported on a dihalide of magnesium or manganese and an organoaluminum compound has a high polymerization activity, and a deashing step is required. It is unnecessary and is a catalyst system suitable for the production of soft propylene polymers. This supported solid catalyst component, after co-milling a dihalide such as magnesium and an electron donor,
It can be prepared by a conventionally known method such as a contact treatment with a titanium compound. However, since the produced non-decalcified and non-extracted soft propylene polymer has a large amount of boiling methyl acetate-soluble content, it has tackiness on the surface of the molded article. As an improvement method thereof, for example, JP-A-59-59
JP 59708 discloses a method using an ether compound and an aromatic carboxylic acid ester as an electron donor. However, the produced polymer has an odor due to the catalyst component, which is not preferable.

[0005]

The object of the present invention is to reduce the content of boiling methyl acetate solubles, to improve the transparency of molded articles, and to improve the surface tackiness.
In addition, a method for producing a soft propylene polymer having almost no odor is provided.

[0006]

TECHNICAL FIELD The present invention relates to a method for producing a propylene polymer, which comprises polymerizing propylene in the presence of a catalyst comprising the following components. Component [A]: aluminum halide and formula R ¹ Si (OR ² ) _4-n [I] (In the formula, R ¹ is an alkyl group having 1 to 8 carbon atoms, a phenyl group, or a benzyl group, and R ² Is an alkyl group having 1 to 8 carbon atoms, and n is 0, 1, 2, or 3. The reaction product with a silicon compound is represented by the formula R ³ MgX [II] (wherein R is ³ is an alkyl group having 1 to 8 carbon atoms, and X is a chlorine atom, a bromine atom, or an iodine atom.), And the resulting carrier is reacted with titanium tetrahalide and phthalic acid. A solid catalyst component obtained by reacting a reaction solid obtained by reacting with an ester and titanium tetrahalide again. Component [B]: Formula AlR ⁴ ₃ [II
I] (in the formula, R ⁴ is an alkyl group having 1 to 6 carbon atoms).

Hereinafter, each component used in the preparation of the catalyst of the present invention and the conditions thereof will be described in detail. In the present invention, the preparation and polymerization of the component [A] are all carried out with nitrogen,
It is performed under an atmosphere of an inert gas such as argon. Further, it is desirable that the raw material for preparing the component [A] is substantially anhydrous. Specific examples of the aluminum halide in the present invention include aluminum chloride, aluminum bromide and aluminum iodide, and among them, aluminum chloride is preferably used.

Specific examples of the silicon compound represented by the formula [I] include tetramethoxysilane, tetraethoxysilane, tetra-n-propoxysilane, tetra-n-butoxysilane, tetra-isopentoxysilane and tetra-.
n-hexoxysilane, methyltrimethoxysilane, methyltriethoxysilane, methyltri-n-butoxysilane, methyltriisopentoxysilane, methyltri-
n-hexoxysilane, ethyltriethoxysilane, ethyltriisopropoxysilane, ethyltriisopentoxysilane, n-butyltriethoxysilane, isobutyltriethoxysilane, isopentyltriethoxysilane, isopentyltri-n-butoxysilane, dimethyl Diethoxysilane, dimethyldi-n-butoxysilane,
Dimethyldiisopentoxysilane, diethyldiethoxysilane, diethyldiisopentoxysilane, diisobutyldiisopentoxysilane, di-n-butyldiethoxysilane, diisobutyldiisopentoxysilane, trimethylmethoxysilane, trimethylethoxysilane, Trimethylisobutoxysilane, triethylisopropoxysilane, tri-n-propylethoxysilane, tri-n
-Butylethoxysilane, triisopentylethoxysilane, phenyltriethoxysilane, phenyltriisobutoxysilane, phenyltriisopentoxysilane,
Diphenyldiethoxysilane, diphenyldiisopentoxysilane, diphenyldioctoxysilane, triphenylmethoxysilane, triphenylethoxysilane, triphenylisopentoxysilane, benzyltriethoxysilane, benzyltributoxysilane, dibenzyldiethoxysilane Is mentioned.

The proportion of aluminum halide used in the reaction is 0.1 to 10 mol per mol of the silicon compound,
It is particularly preferably 0.1 to 2 mol. The reaction between the aluminum halide and the silicon compound is usually carried out by stirring both compounds in an inert organic solvent at a temperature in the range of -50 to 100 ° C for 0.1 to 2 hours.
The reaction proceeds exothermically and the reaction product is obtained as a solution in an inert organic solvent. The reaction product is subjected to reaction with a magnesium compound as a solution in an inert organic solvent.

Among the magnesium compounds represented by the formula [II], alkyl magnesium chloride in which X is a chlorine atom is preferably used, and specific examples thereof include methyl magnesium chloride, ethyl magnesium chloride, n-butyl magnesium chloride, n-hexyl magnesium chloride is mentioned. The amount of the magnesium compound used is preferably 0.05 to 4 mol, particularly 1 to 3 mol, per mol of the aluminum halide used for preparing the reaction product. The method for reacting the reaction product with the magnesium compound is not particularly limited, but an ether solution of the magnesium compound or a mixed solvent solution of the ether and the aromatic hydrocarbon is gradually added to the inert solvent solution of the reaction product. It is convenient to do so or by adding in the reverse order. Examples of the above ether include those represented by the formula R ⁵ —O—R ⁶
(In the formula, R ⁵ and R ⁶ represent an alkyl group having 2 to 8 carbon atoms.) Are preferably used, and specific examples thereof include diethyl ether, diisopropyl ether, and di-n-butyl ether. , And diisoamyl ether.

The reaction temperature is usually -50 to 100 ° C, preferably -20 to 25 ° C. The reaction time is not particularly limited, but is usually 5 minutes or longer. The carrier precipitates as the reaction progresses. The carrier thus obtained can be subjected to the next treatment as a reaction mixture, but it is preferable to separate the carrier in advance and wash it with an inert organic solvent before subjecting it to the next treatment. Specific examples of the titanium tetrahalide include titanium tetrachloride, titanium tetrabromide and titanium tetraiodide, and among them, titanium tetrachloride is preferably used. The amount of titanium tetrahalogenate used is preferably 1 mol or more, particularly 2 to 100 mol, per 1 mol of the magnesium compound used in the preparation of the carrier.

Specific examples of the phthalic acid ester used in the present invention include monoethyl phthalate, dimethyl phthalate, monoisobutyl phthalate, diethyl phthalate,
Ethyl isobutyl phthalate, di-n-propyl phthalate, diisopropyl phthalate, di-n-butyl phthalate, diisobutyl phthalate, di-n-heptyl phthalate, di-2-ethylhexyl phthalate, di-n phthalate.
-Mono- or dialkyl esters of phthalic acid, such as octyl, dineopentyl phthalate, diisodecyl phthalate, mono- or dialkenyl esters of phthalic acid, such as monoallyl phthalate, diallyl phthalate, and benzylbutyl phthalate, phthalic acid Examples include monophenyl and diphenyl phthalate. The amount of phthalate ester used is preferably 0.1 to 10 mmol per 1 g of the carrier. Examples of the method for reacting the carrier with titanium tetrahalide and phthalic acid ester include (1) a method in which titanium tetrahalide and then phthalic acid ester are added to an inert organic solvent slurry of the carrier, and (2) above. A method in which a phthalic acid ester and then titanium tetrahalide are added to the slurry and reacted, and (3) a method in which titanium tetrahalide and phthalic acid ester are simultaneously added to the slurry and reacted, among which the above (1 )
Is preferred. In the above method (1), the carrier may be contacted with titanium tetrahalide, and then the contact solid may be separated and washed, and then the contact solid may be reacted with the phthalic acid ester. The reaction temperature is 0 to 200 ° C, especially 5 to
The temperature is preferably 150 ° C., and the reaction time is not particularly limited, but is usually 5 minutes or longer. By reacting the reaction solid thus obtained with titanium tetrahalide again, a solid catalyst component (component [A]) is obtained. The conditions such as the amount of titanium tetrahalide used, the contact temperature, and the contact time are the same as those used when preparing the reaction solid. From the mixture containing the component [A] thus obtained, the component [A] is separated by filtration, decanting, etc., and washed with an inert organic solvent. Specific examples of the component [B] include trimethyl aluminum, triethyl aluminum, triisobutyl aluminum, tri-n-hexyl aluminum and the like. The amount of component [B] used is the same as titanium 1 in component [A].
It is usually 1 to 1000 mol per gram atom. still,
The component [B] can be used in combination with an equimolar amount or less of a dialkylaluminum halide.

In the present invention, propylene is polymerized by using the catalyst composed of the components [A] and [B]. Further, propylene may be homopolymerized, but propylene and one or more kinds of other α-olefins can be copolymerized with propylene. Specific examples of α-olefins other than propylene include ethylene, butene-1,4-
Methyl pentene-1 and hexene-1 are mentioned. Further, hydrogen can be made to coexist as a molecular weight regulator of the produced polymer. The polymerization reaction can be carried out in the same manner as the polymerization reaction of α-olefin using a general Ziegler-Natta type catalyst. The polymerization reaction can be performed in a liquid phase or a gas phase. When the polymerization reaction is carried out in the liquid phase, an inert organic solvent may be used as the polymerization solvent, or a liquid α-olefin itself may be used. In the present invention, examples of the inert organic solvent used during the preparation of the component [A] and, optionally, during the polymerization reaction include aliphatic hydrocarbons such as hexane and heptane, toluene, benzene and xylene. Aromatic hydrocarbons and halides of these hydrocarbons can be mentioned. The polymerization reaction is carried out with water and oxygen substantially removed. Polymerization temperature is usually 30 to 1
The temperature is 00 ° C., and the polymerization pressure is usually 1 to 80 Kg / cm ² .

[0014]

The propylene polymer obtained by the production method of the present invention has a boiling n-heptane insoluble content of 35 to 70.
%, The boiling methyl acetate soluble content is as low as 2% or less, the melting point is 130 to 160 ° C., which is an amorphous soft resin, and the molded film has good transparency and low surface tackiness. The catalyst system of the present invention has high polymerization activity and does not require a deashing step.

[0015]

EXAMPLES Examples and comparative examples of the present invention will be described below. In the examples, the “polymerization activity” is the polymer yield (g) per 1 g of the solid catalyst component used in the polymerization reaction. "HI" is the weight percentage of the extraction residue when the produced polymer was extracted with boiling n-heptane for 20 hours with respect to the total polymer. "MI" means ASTM D
² under a load of 2.16 kg / cm ² according to -1238
It is the melt index of the polymer measured at 30 ° C. The boiling methyl acetate soluble content is the weight percentage of the soluble content when the produced polymer is extracted with boiling methyl acetate for 20 hours with respect to the total polymer. The melting point was measured by DSC. The transparency, surface tackiness, and odor on the molded product were measured by preparing a sheet having a thickness of 1 mm by hot pressing.

Examples 1-3 (1) Preparation of solid catalyst component Toluene suspension 4 of 15 mmol of anhydrous aluminum chloride
After adding 15 mmol of methyltriethoxysilane to 0 ml and reacting at 25 ° C. for 0.5 hours, the temperature was raised to 60 ° C. and further reaction was performed for 1 hour. The reaction product mixture was cooled to −5 ° C., 18 ml of a solution of 30 mmol of n-butylmagnesium chloride in diisopropyl ether was added to the reaction product mixture in 0.5 hours, and the temperature was raised to 30 ° C. to react for 1 hour. The precipitated solid was filtered off and washed with toluene. 30 ml of a toluene suspension of 4.90 g of the obtained carrier.
Then, 150 mmol of titanium tetrachloride, and then di-phthalate
3.2 mmol of n-heptyl was added and reacted at 90 ° C. for 1 hour. The reaction solid was filtered off at 90 ° C., n-heptane,
Then, it was washed with toluene. To 30 ml of a toluene suspension of the reaction solid, 150 mmol of titanium tetrachloride was added,
The reaction was carried out at 0 ° C for 1 hour. 90 ° C. of the obtained solid catalyst component
After filtering off with n-heptane and washing with n-heptane,
0 ml of slurry was made. The titanium content of the solid catalyst component was 3.55% by weight.

(2) Polymerization A glass ampoule containing a slurry of a solid catalyst component (4.82 mg as a solid catalyst component) was attached to an autoclave with an internal volume of 21 equipped with a stirrer, and then the air in the autoclave was replaced with nitrogen. .. Then, 4.9 ml of an n-heptane solution containing 1.07 mmol of triethylaluminum was charged into the autoclave. Hydrogen was charged into the autoclave until the partial pressure shown in Table 1 was reached, then 1200 ml of liquid propylene was introduced, and the autoclave was shaken. After heating the contents of the autoclave to 65 ° C, stirring is started to crush the glass ampoule and
The propylene was polymerized for an hour. After the completion of the polymerization reaction, unreacted propylene was discharged, glass fragments were removed, and the produced polypropylene was dried under reduced pressure at 50 ° C. for 20 hours to obtain white powdery polypropylene. The polymerization conditions and the polymerization results are shown in Table 1 and Table 2, respectively. The molded film had good transparency, no odor, and almost no surface tackiness was observed.

Comparative Example 1 Di-n-heptyl phthalate was replaced with ethyl benzoate.
The solid catalyst component was prepared and polymerized in the same manner as in Example 1 except that 3 mmol was used. The polymerization conditions and the polymerization results are shown in Table 1 and Table 2, respectively. The formed film had an odor. Comparative Example 2 A solid catalyst component was prepared and polymerized in the same manner as in Example 1 except that no electron donor such as phthalic acid diester was used during catalyst preparation. The polymerization conditions and the polymerization results are shown in Table 1 and Table 2, respectively. The film having a high boiling methyl acetate-soluble content of 2.73% had surface tackiness.

Examples 4 to 9 The solid catalyst component was prepared and polymerized in the same manner as in Example 1 except that the phthalic acid diester shown in Table 1 was used instead of di-n-heptyl phthalate. The polymerization conditions and the polymerization results are shown in Table 1 and Table 2, respectively. The molded film had good transparency, no odor, and almost no surface tackiness was observed.

Examples 10 to 12 Preparation of the solid catalyst component in the same manner as in Example 2 except that 15 mmol of the silicon compound shown in Table 3 was used in place of methyltriethoxysilane in the preparation of the solid catalyst component, and Polymerization was carried out. The polymerization conditions and the polymerization results are shown in Table 3, respectively. The molded film had good transparency, no odor, and almost no surface tackiness.

[0021]

[Brief description of drawings]

FIG. 1 is a flow chart showing a polymerization method of the present invention and a step of preparing a catalyst solid component used in the polymerization.

[Table 1]

[Table 2]

[Table 3]

 ─────────────────────────────────────────────────── ─── Continued Front Page (72) Inventor Shinichiro Yamada 8-1 Goi Minamikaigan, Ichihara City, Chiba Ube Industries Ltd. Chiba Research Institute

Claims (1)

[Claims] 1. A method for producing a propylene polymer, which comprises polymerizing propylene in the presence of a catalyst comprising the following components. Component [A]: aluminum halide and formula R ¹ Si (OR ² ) _4-n [I] (In the formula, R ¹ is an alkyl group having 1 to 8 carbon atoms, a phenyl group, or a benzyl group, and R ² Is an alkyl group having 1 to 8 carbon atoms, and n is 0, 1, 2, or 3. The reaction product with a silicon compound is represented by the formula R ³ MgX [II] (wherein R is ³ is an alkyl group having 1 to 8 carbon atoms, and X is a chlorine atom, a bromine atom, or an iodine atom.), And the resulting carrier is reacted with titanium tetrahalide and phthalic acid. A solid catalyst component obtained by reacting a reaction solid obtained by reacting with an ester and titanium tetrahalide again. Component [B]: An aluminum compound represented by the formula AlR ⁴ ₃ [III] (wherein, R ⁴ is an alkyl group having 1 to 6 carbon atoms).