JPH0713103B2 - Polymerization method of propylene - Google Patents

Description

TECHNICAL FIELD The present invention relates to a method for polymerizing propylene. Specifically, it relates to a method for producing a highly crystalline polypropylene by a specific polymerization method.

Conventional technology Polypropylene is a polymer with excellent rigidity, but its impact resistance, especially at low temperatures, is inferior, so impact resistance can be improved by block copolymerization with other olefins such as ethylene. (For example, Japanese Patent Publication No. 44-20621, Japanese Patent Publication No. 49-24593, Japanese Patent Publication No. 49-12589). However, when block copolymerization is inevitably performed, the rigidity becomes poor in proportion to the improvement in impact resistance. Therefore, improving the rigidity of polypropylene itself does not only improve the physical properties of polypropylene but also that of polypropylene. It is also extremely important in terms of improving the physical properties of the block copolymer.

Problems to be solved by the invention Since the rigidity of a crystalline polymer such as polypropylene correlates with the degree of crystallization of the polymer, adding a nucleating agent improves the crystallization temperature and crystallinity of the polymer to improve the rigidity of the polymer. Although it is often improved, if a relatively large amount of nucleating agent is not added, it is not effective, and if a large amount of nucleating agent is added, unevenness in the partial physical property balance of the molded product due to uneven distribution of the nucleating agent. As a result, there is a problem that the physical properties of the molded product are poorly balanced, or the nucleating agent bleeds and the molded product is poorly identified.

Means for Solving the Problems The present inventors completed the present invention by intensively studying a method for producing polypropylene having excellent rigidity by solving the above problems.

That is, the present invention is a method for polymerizing propylene using a catalyst composed of a transition metal catalyst component containing a trivalent and / or tetravalent titanium halide and an organoaluminum compound, in which an equivalent weight ratio to the transition metal catalyst component is not less than A method for producing a highly crystalline polypropylene, characterized in that the catalyst treated with vinyl naphthalene is used.

In the present invention, the catalyst comprising the transition metal catalyst component and the organoaluminum compound is not particularly limited, and various known catalyst systems which give polypropylene having high stereoregularity can be used. Titanium halides are preferably used as the transition metal catalyst component. For example, titanium trichloride obtained by reducing titanium tetrachloride with metallic aluminum, hydrogen or organic aluminum, or those modified with an electron donating compound and organic aluminum. Compound Further, if necessary, a catalyst system comprising a stereoregularity improver such as an oxygen-containing organic compound, a carrier such as magnesium halide, or a product obtained by treating them with an electron donating compound and supporting titanium halide. And a catalyst system comprising an organoaluminum compound and optionally a stereoregularity improver such as an oxygen-containing organic compound. (For example, various examples are described in the following literature. Ziegler-Natta Catalysts and
Polymerization by John Boor Jr (Academic Press),
Journal of Macromolecular Science-Reviews in Macr
omolecular Chemistry and Physics C24 (3) 355-385
(1984) C25 (1) 57-97 (1985)).

Here, oxygen-containing compounds such as ethers, esters, orthoesters, and alkoxysilicons can be preferably used as the stereoregularity improver or electron donor, and alcohols, aldehydes, water and the like can also be used as electron donors.

As the organic aluminum compound, trialkylaluminum, dialkylaluminum halide, alkylaluminum sesquihalide, alkylaluminum dihalide can be used, and examples of the alkyl group include a methyl group, an ethyl group, a propyl group, a butyl group, and a hexyl group. Examples of halides include chlorine, bromine and iodine. Preferred titanium halides are titanium tetrachloride obtained by reducing titanium tetrachloride with aluminum or organoaluminum, modified with ether or ester, or titanium tetrachloride obtained by co-milling magnesium chloride and an organic compound. Or the reaction product of magnesium chloride and alcohol is dissolved in a hydrocarbon solvent and then treated with a precipitating agent such as titanium tetrachloride to make it insoluble in the hydrocarbon solvent. It is a supported titanium halide obtained by a method such as a modification treatment with an electron donating compound and a treatment with titanium tetrachloride.

In the present invention, what is important is that the transition metal catalyst component is previously treated with vinyl naphthalene in an equivalent amount or more,
During this treatment, it is preferable to contact the transition metal catalyst component with the organoaluminum. The use ratio of the organoaluminum compound and the transition metal catalyst component during the treatment with vinylnaphthalene may be the same as or smaller than the ratio during the subsequent polymerization of propylene, and the amount ratio may be as a ratio. Is 0.5 to 1000. At that time, a stereoregularity improver may be allowed to be present, and the ratio thereof is generally 0.01 to 300. The contact treatment temperature and the contact treatment time are not particularly limited, but generally, the temperature is the same as or lower than the temperature during the subsequent propylene polymerization, and the contact treatment time is several minutes to several hours. Is common. This catalytic treatment is carried out in an inert medium for the Ziegler-Natta catalyst such as peptane, hexane, heptane, octane, benzene, toluene, xylene, ethylbenzene or mixtures thereof.

As vinylnaphthalene, α-vinylnaphthalene and β
-Vinylnaphthalene can be used. The use ratio of vinylnaphthalene to the transition metal catalyst component is 1 equivalent or more, preferably 1 to 100 equivalents.

In the present invention, the polymerization of propylene can be carried out in the above-mentioned inert medium, or can be carried out by a bulk polymerization method in which propylene itself is a liquid medium, or a gas phase polymerization method in which a substantially liquid inert medium does not exist, Polymerization temperature is room temperature ~
The temperature is 100 ° C., and the polymerization pressure is room temperature to 50 kg / cm ² -gauge.

The present invention also includes not only propylene homopolymerization but also copolymerization with other α-olefins such as ethylene in a small amount of up to several%, or a polymer in which ethylene or other α-olefin is optionally added in a later stage. It can also be applied to the production of so-called block copolymers in which the copolymerization is such that they account for 20 to 95 wt% of

Effect By carrying out the method of the present invention, a highly crystalline polypropylene can be easily produced, which is extremely industrially significant.

Examples The present invention will be further described below with reference to Examples.

Example 1 A vibration mill equipped with four grinding pots with an inner volume of 4 containing 9 kg of steel balls having a diameter of 12 mm is prepared. 300 g magnesium chloride and tetraethoxysilane in a nitrogen atmosphere in each pot
60 ml and 45 ml of α, α, α-trichlorotoluene were added and crushed for 40 hours.

300 g of the above co-ground product was placed in a flask of 5 and titanium tetrachloride was added.
1.5 and toluene 1.5 were added and the mixture was stirred at 100 ° C. for 30 minutes. Then, leave it standing and remove the supernatant liquid in the same manner as in titanium tetrachloride 1.5.
Toluene 1.5 was added, and the mixture was stirred at 100 ° C. for 30 minutes, then allowed to stand, the supernatant was removed, and the solid content was washed with n-heptane (4) repeatedly 10 times. 1 part of the obtained solid catalyst slurry Was sampled and the titanium content was analyzed and found to be 1.9% by weight.

ii) Polymerization reaction In a flask with an internal volume of 200 ml, under a nitrogen atmosphere, 100 ml of toluene,
20 mg of the above solid catalyst, diethylaluminum chloride.
128 ml, 0.06 ml of methyl p-toluate, 0.03 ml of triethylaluminum and 0.2 g of α-vinylnaphthalene (10 weight ratio) were added, and after stirring for 30 minutes at room temperature, 0.05 ml of triethylaluminum was added. This catalyst slurry was put into an autoclave with an internal volume of 5, then propylene 1.8K
g and 3.3 Nl of hydrogen were added and a polymerization reaction was carried out at 75 ° C for 2 hours. After the polymerization reaction, propylene in the end reaction was purged and the polymer taken out was dried at 80 ° C. and 60 mmHg for 12 hours. 480g powder
Yes, the intrinsic viscosity in a 135 ° C. tetralin solution (hereinafter abbreviated as η), the ratio of the extraction residual ratio when socked with boiling n-heptane for 6 hours and extracted using an extractor (hereinafter abbreviated as II), Next, add a phenolic stabilizer in a ratio of 10/10000 and calcium stearate in a ratio of 15/10000 and granulate. Measure the melt flow index to obtain a thickness of 1 mm.
An injection sheet was prepared and the bending rigidity was measured.

Melt flow index ASTM D1238 (230 ℃) Flexural rigidity ASDM D747-63 (20 ℃) Also, the melting point and crystallization temperature are set to the maximum peak temperature by increasing or decreasing the temperature at 10 ℃ / min using a differential thermal analyzer. It was measured. The results are shown in the table.

Comparative Example 1 Polymerization was performed in the same manner as in Example 1 except that the treatment with α-vinylnaphthalene was not performed prior to the polymerization of propylene, and 475 kg of polypropylene was obtained. The analysis results are shown in the table.

Example 2 0.3 g (15 weight ratio) of β-vinylnaphthalene was used instead of 0.2 g of α-vinylnaphthalene, and 0.08 ml of triethylaluminum was first used to carry out polymerization without adding when charging to an autoclave. . 460 g of polypropylene were obtained. The analysis results are shown in the table.

Example 3 Commercially available high activity titanium trichloride was used as a transition metal catalyst component. (TAC-S-21 manufactured by Toho Titanium Co., Ltd.) 100 mg of the above-mentioned highly active titanium trichloride in 1.0 ml of toluene, 1.0 ml of diethyl aluminum chloride, α-vinylnaphthalene
Contact treatment was carried out at 0.2 g (2 weight ratio) at 50 ° C. for 30 minutes.

Next, this slurry was placed in an autoclave having an internal volume of 5, 1.8 kg of propylene and 4.4 Nl of hydrogen were added, and a polymerization reaction was carried out at 75 ° C for 4 hours.

950 g of polypropylene were obtained. 10% of this polypropylene was autoclaved in the presence of 10 ml of propylene oxide.
After treating at 0 ° C. for 1 hour, granulation was performed in the same manner as in Example 1 and the physical properties were measured. The results are shown in the table.

Comparative Example 2 Same as Example 3 except that the treatment with α-vinylnaphthalene was not performed prior to the polymerization of propylene. 980 g of polypropylene powder was obtained. The results are shown in the table.

Comparative Example 3 Polypropylene 94 was prepared in the same manner as in Example 3 except that the amount of α-vinylnaphthalene used was 0.08 g (0.8 weight ratio).
I got 0g. The results are shown in the table.

Example 4 930 g of polypropylene was obtained in the same manner as in Example 3 except that 0.4 g of β-vinylnaphthalene (4 weight ratio) was used instead of 0.2 g of α-vinylnaphthalene. The results are shown in the table.

[Brief description of drawings]

FIG. 1 is a flow chart of the Ziegler catalyst according to the present invention.

Claims (1)

[Claims] 1. A method for polymerizing propylene using a catalyst comprising a transition metal catalyst component containing trivalent and / or tetravalent titanium halide and an organoaluminum compound, wherein an equivalent weight ratio to the transition metal catalyst component is used in advance. A method for producing a highly crystalline polypropylene, characterized by using the above-mentioned catalyst treated with vinylnaphthalene.