JP2516199B2 - Continuous propylene polymerization method - Google Patents

Description

TECHNICAL FIELD The present invention relates to a method for polymerizing propylene. More particularly, it relates to a method for continuously producing highly crystalline polypropylene using a specific catalyst.

[Conventional technology]

Polypropylene is a general-purpose polymer having relatively excellent rigidity and excellent transparency, and is widely used for various purposes. Further, a method of copolymerizing with other α-olefin such as ethylene for the purpose of improving the impact resistance of polypropylene (especially at low temperature) is known (for example, Japanese Patent Publication No.
-20621, JP-B-49-24593, JP-B-49-12
No. 589).

Whether it is a propylene homopolymer or a copolymer with another α-olefin, improving the rigidity of polypropylene is effective in improving the physical properties, and therefore it is already well known to add various nucleating agents. It is known and some examples are known.

Further, it is known that the nucleating agent or the like from a molded article of polypropylene does not bleed and exhibits a further effect, using a polymer nucleating agent (for example, JP-A-60-139710, JP-A-60-139731, etc.).

[Problems to be solved by the invention]

The method using the above-mentioned polymer nucleating agent is extremely excellent,
The rigidity and transparency of films and sheets are greatly improved. However, in a method in which vinylcyclohexane or the like is polymerized on a solid catalyst and then propylene is polymerized after forming a catalyst covered with a polymer nucleating agent by washing or the like, the activity per solid catalyst is significantly reduced, and the resulting polypropylene There was a problem that the ratio of boiling n-heptane extraction residual ratio (abbreviated as II in the following) was drastically reduced, and the appearance of the molded product was poor when the obtained polymer was used as a molded product. On the other hand, in the method of polymerizing propylene as it is by treating with vinylcyclohexane or the like under the original condition of polymerizing propylene without performing operations such as washing, there is a problem that the above activity and II are substantially reduced in batch polymerization. However, when continuous polymerization is carried out, there is a problem in that if the reaction is continued as it is, the activity of the polymerization and a significant decrease.

[Means for solving problems]

The present inventors have earnestly studied a method for solving the above problems and completed the present invention.

That is, the present invention includes: a) a solid catalyst component in which a trivalent or tetravalent titanium halide is supported on a carrier containing magnesium halide on at least the surface thereof; An organoaluminum compound having two or more aluminum atoms, c) a stereoregularity improver selected from an ester, an ether, an orthoester, an alkoxysilicon compound and d) a catalyst comprising a halogen-containing organoaluminum compound. In the method of polymerizing propylene or propylene and another α-olefin, a)
A solid catalyst component, and c) a part to all of the stereoregularity improver,
d) a part to all of the halogen-containing organoaluminum compound and b) 0 to a part of the organoaluminum compound at a vinyl cycloalkane and / or a 3- or 4-position having 5 or more carbon atoms in an inert hydrocarbon solvent. A method for continuous polymerization of propylene, which comprises contact-treating with a branched olefin and then introducing the treatment mixture, the rest of the components c) and d) and the component b) into a propylene polymerization zone.

In the present invention, many examples are already known as a) solid catalyst component, and trivalent or tetravalent titanium halide is supported on a carrier containing magnesium halide which gives polypropylene with high activity and high stereoregularity. There is no particular limitation as long as it is a solid catalyst component formed by For example, a method in which various organic compounds (preferably oxygen-containing organic compounds) and magnesium halide are co-ground and used as a carrier, followed by contact treatment with titanium tetrachloride or titanium trichloride or those diluted with various solvents, Magnesium halide is solubilized in hydrocarbon solvent or halogenated hydrocarbon solvent with ether, alcohol, amide, etc., and then it is a precipitating agent such as titanium halide, silicon halide, etc. in the presence or absence of oxygen-containing organic compounds. A method of treating under, precipitating magnesium halide, then using as a carrier without contacting with or containing an oxygen-containing organic compound, and carrying trivalent or tetravalent titanium halide in the same manner as described above, organomagnesium as alcohol Contact treatment with alkoxy silicon, and then the solid component obtained is further treated with halo. Of the above-mentioned magnesium compound as a carrier by carrying out a contact treatment with a phosphorus compound and then with or without contact with an oxygen-containing organic compound, and carrying a trivalent or tetravalent titanium halide in the same manner as above. In the case of precipitating, a carrier is produced by allowing an inert solid such as alumina or silica to exist, and then a trivalent or tetravalent titanium halide is supported.

Preferred examples of the oxygen-containing organic compound include carboxylic acid esters, ethers, alkoxysilicones, and orthocarboxylic acid esters.

In the present invention, as the component b), trialkylaluminum such as trimethyl, aluminum, triethylaluminum, tripropylaluminum, triisobutylaluminum, trihexylaluminum or a mixture thereof, or the above-mentioned trialkylaluminum and water according to a known method. , A compound obtained by a reaction with ammonia or a primary amine, for example, (C ₂ H ₅ ) ₂ Al-O-Al (C ₂ H ₅ ) ₂ , (C ₂ H ₅ ) ₂ Al-N-Al ( C ₂ H ₅ ) ₂ and the like.

In the present invention, examples of the ester, ether, orthoester, and alkoxysilicon compound which are the components of c) specifically include ethyl acetate, methyl acrylate, methyl methacrylate, ethyl benzoate, methyl toluate,
Esters such as triethyl phosphate and triphenyl phosphate, ethers such as diethyl ether, diisoaluminum ether, diphenyl ether and dinaphthyl ether,
Orthoesters such as methyl orthoformate, ethyl orthoformate, methyl orthoacetate, methyl orthobenzoate and methyl orthobenzoate, tetraethoxysilane, triethoxyethylsilane, triethoxyphenylsilane, trimethoxyphenylsilane, trimethoxyvinylsilane Examples thereof include alkoxy silicons.

In the present invention, as the halogen-containing organoaluminum compound which is the component d), diethylaluminum chloride, diethylaluminum bromide, diethylaluminum iodide, dimethylaluminum chloride,
Examples thereof include dipropylaluminum chloride, dipropylaluminum bromide, diethylaluminum sesquichloride, diethylaluminum sesquibromide, dipropylaluminum sesquichloride, ethylaluminum dichloride and propylaluminum dichloride, and dialkylaluminum halides are particularly preferably used.

The vinyl cycloalkane used in the present invention and the olefin having 5 or more carbon atoms and branched at the 3-position or 4-position include:
Vinylcyclohexane, vinylcyclopentane, vinylcyclobutane, 3-methylbutene-1,4-methylpentene, 4-methylhexene, 4,4-dimethylpentene,
4,4-Dimethylhexene, vinylnaphthalene and the like can be exemplified, and among them, vinylcyclohexane, 3-methylbutene-1,4,4-dimethylpentene, 4,4-dimethylhexene and the like can be preferably used.

Prior to the polymerization of propylene in the present invention, the contact treatment with the vinyl compound is carried out in an inert hydrocarbon medium such as pentane, hexane, heptane, nonane, decane, cyclohexane, benzene, toluene, xylene and ethylbenzene, It is usually carried out at 0 to 70 ° C, preferably 10 to 60 ° C. The contact time is generally several minutes to several hours, and the vinyl compound concentration is generally 0.1 to 100 g / l. Preferably, the reaction temperature for the vinyl compound to polymerize 0.001 to 200 times by weight per solid catalyst component, the reaction time,
It is carried out under the condition of the liquid phase concentration of the vinyl compound. What is important here is the amount of a) used in the polymerization of propylene of each of the above components a), b), c) and d).
Ingredients in total amount, c) component in partial to total amount, d) component in partial amount
The total amount of component b) is 0 to a part of which is used for contact with a vinyl compound prior to the polymerization of propylene. Preferably, component b) is 0 to 10%, component c) is 5 to 100%, d )
Component is 20-100%, particularly preferably b) component is 0%,
The c) component is 10 to 100%, and the d) component is 50 to 100%. If a large amount of the component b) is used in the contact treatment with a vinyl compound, the activity and II of the propylene are decreased during polymerization, which is not preferable. If the amount of the component c) used is too small, II is lowered during the polymerization of propylene, which is not preferable. If the amount of component d) used is too small, not only does II decrease during the polymerization of propylene, but the effect of polymerization of the vinyl compound that precedes the polymerization of propylene is almost lost. This treatment is preferably carried out batchwise.

In the present invention, propylene is continuously polymerized by continuously introducing the above catalyst into the propylene polymerization zone.

The conditions for the propylene polymerization zone include a solvent polymerization method,
It may be either a bulk polymerization method or a gas phase polymerization method, and the polymerization temperature is generally 0 to 90 ° C, preferably 30 to 80 ° C, and the polymerization pressure is generally atmospheric pressure to 50 kg / cm ² · gauge. Target.

Polymerization of propylene in the polymerization zone includes not only propylene homopolymerization but also random copolymerization with other α-olefins such as ethylene and butene-1, or block copolymerization.

Further, in the present invention, a molecular weight modifier such as hydrogen can be used in the polymerization of a vinyl compound or the polymerization of propylene which precedes the polymerization of propylene.

〔The invention's effect〕

By carrying out the method of the present invention, it is possible to obtain polypropylene with high II and high crystallinity without impairing the polymerization activity, which is extremely valuable industrially.

〔Example〕

 Hereinafter, the present invention will be described with reference to examples.

Experimental Example 1 Production of solid catalyst component 1 A vibration mill equipped with four grinding pots with an inner volume of 4 l containing 9 kg of steel balls having a diameter of 12 mm is prepared. Magnesium chloride 300g, tetraethoxysilane in each pot under nitrogen atmosphere
60 ml and 45 ml of α, α, α-trichlorotoluene were added and crushed for 40 hours. To a 50 l reactor, 3 kg of the pulverized product, 10 l of titanium tetrachloride and 10 l of toluene were added, and after stirring at 80 ° C. for 1 hour, the mixture was allowed to stand still and the supernatant was removed twice. Then, the solid content was washed with 40 l of n-heptane to obtain a solid catalyst component A. This solid catalyst component contains 1.6 wt% titanium
Contained.

Experimental Example 2 Preparation of solid catalyst component 2 Kerosene 3 l, 2-ethylhexyl alcohol 2.8 l, ethyl benzoate 276 ml and magnesium chloride 5 in a 10 l reactor.
Add 70 g and stir at 130 ℃ for 1 hour to make a uniform solution, 50l
Transfer the above homogenized solution to the reactor, cool to -20 ° C and
Titanium tetrachloride was charged for 1 hour and then heated to 90 ° C for 2 hours to precipitate the solid catalyst component.
It was treated at 90 ° C. for 2 hours. Then, the mixture was allowed to stand still to remove the supernatant, 12 l of titanium tetrachloride was added, and the mixture was heated at 80 ° C. for 1 hour. Then, the mixture was allowed to stand to remove the supernatant, and the solid content was washed 7 times with 40 l of n-heptane to obtain a solid catalyst component B. This solid catalyst component contained 2.6 wt% titanium.

Example 1 50 g of the solid catalyst component A obtained in the above experimental example, 213 ml of diethyl aluminum chloride, 20 ml of methyl p-toluate,
200 ml of vinylcyclohexane and n-heptane 1 were added, and the mixture was stirred at 40 ° C for 2 hours. A part thereof was sampled and the weight amount of vinylcyclohexane per solid catalyst component was analyzed to find that it was 0.3 g / g.

75 kg of propylene was put into an autoclave having an internal volume of 500 l, the temperature was raised to 75 ° C, and then hydrogen was charged so that the hydrogen concentration became 3.5 Nl. Next, 2.5 g / h of the above-mentioned mixed slurry as a solid catalyst component, 4 ml / h of methyl p-toluate and 7 ml / h of triethylaluminum were charged from separate feed ports, and liquefied propylene was charged at 75 Kg / h to prepare a slurry. To 75
Polymerization was continued at 75 ° C for 15 hours while introducing hydrogen so that the gas phase hydrogen concentration became 3.5 Nl while extracting at Kg / h.

The powder taken out from the slurry was analyzed 10 hours after the start of polymerization. The results are shown in the table.

The polypropylene yield per solid catalyst component was calculated from the titanium content in the powder, the intrinsic viscosity was 135 ° C. tetralin solution, and the boiling n-heptane extraction residual ratio was
It was calculated by extracting for 6 hours with a Kumagawa type extractor.
Also, the melting point and crystallization temperature are measured with a differential scanning calorimeter.
It was measured by raising or lowering the temperature at ° C / min.

Comparative Example 1 The same procedure as in Example 1 was carried out except that the contact treatment prior to the polymerization of propylene was carried out in the absence of vinylcyclohexane. The results are shown in the table.

Example 2 The procedure of Example 1 was repeated except that the solid catalyst component B was used as the solid catalyst component and 3-methylbutene-1 was used instead of vinylcyclohexane. The polymerization amount of 3-methylbutene-1 was 0.4 g / g solid catalyst component. The results are shown in the table.

Example 3 The procedure of Example 1 was repeated, except that 4,4-dimethylpentene-1 was used instead of vinylcyclohexane. The results are shown in the table.

Comparative Example 2 The same as Example 2 except that 3-methylbutene-1 was not used. The results are shown in the table.

Comparative Example 3 The whole amount of all the components added during the polymerization of propylene was used for the contact in the first stage, and when introduced into the autoclave for the polymerization of propylene, the nozzle was a double tube and the catalyst treated from the inner tube was installed. In addition, by charging n-heptane to the outside, the catalyst charging nozzle was prevented from being blocked and the polymerization was carried out. The results are shown in the table.

Comparative Example 4 The same procedure as in Example 1 was carried out except that 50 g of ethylene was charged instead of vinylcyclohexane, and the polymerization amount of ethylene per solid catalyst was 0.9 g / g. Polymerization and analysis were performed in the same manner as in Example 1 using this slurry. The results are as shown in the table, and the melting point and crystallization temperature were low.

Comparative Example 5 The same procedure as in Example 1 was carried out except that 100 g of propylene was charged instead of vinylcyclohexane, and the amount of propylene polymerized per solid melt was 1.7 g / g. Polymerization and analysis were performed in the same manner as in Example 1 using this slurry. The results are as shown in the table, and the melting point and crystallization temperature were low.

[Brief description of drawings]

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

Claims (1)

(57) [Claims] 1. A solid catalyst component comprising a) a carrier containing magnesium halide on at least the surface thereof and carrying trivalent or tetravalent titanium halide, b) bound to each other by trialkylaluminum or oxygen or nitrogen atoms. An organoaluminum compound having two or more aluminum atoms, c) a stereoregularity improver selected from an ester, an ether, an orthoester, an alkoxysilicon compound and d) a catalyst comprising a halogen-containing organoaluminum compound. In the method of polymerizing propylene or propylene and another α-olefin, a) a solid catalyst component and c) a part to all of the stereoregularity improver, d)
A part to all of the halogen-containing organoaluminum compound and b) 0 to a part of the organoaluminum compound are branched at a 3- or 4-position of vinylcycloalkane and / or a carbon number of 5 or more in an inert hydrocarbon solvent. After catalytic treatment with olefins, the treatment mixture and the balance of components c), d),
A method for continuous polymerization of propylene, which comprises introducing the component b) into a polymerization zone of propylene.