JPS6337104A - Continuous polymerization of propylene - Google Patents

Abstract

PURPOSE:To continuously obtain highly crystalline polypropylene, by previously subjecting part of catalyst components to contact treatment with an alkylvinylsilane or alkylallylsilane in an inert hydrocarbon solvent in continuously polymerizing propylene using a specific catalyst. CONSTITUTION:Propylene is continuously polymerized by using a catalyst consisting of (A) a solid catalyst containing a Ti halide supported on a carrier containing an Mg halide on at least the surface thereof, (B) a trialkylaluminum or organoaluminum compound having >=2 Al atoms mutually linked with O or N atom, (C) a stereoregularity improving agent selected from esters, ethers, orthoesters and alkoxysilicon compounds and (D) a halogen-containing organoaluminum compound in a polymerization zone. In the process, part - all of the components (A) and (C), part - all of the component (D) and 0% - part of the component (B) are previously subjected to contact treatment with an alkylvinylsilane or alkylallylsilane and the treated blend and the remainders of the components (C) and (D) and component (B) are introduced into the polymerization zone.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Field of Application) The present invention relates to a method for polymerizing propylene. Specifically, the present invention relates to a method for continuously producing highly crystalline polypropylene using a specific catalyst.

(Prior Art) Polypropylene is a general-purpose polymer with relatively excellent rigidity and transparency, and is widely used for various purposes. Additionally, for the purpose of improving the impact resistance (especially at low temperatures) of polypropylene, a method of copolymerizing it with other α-olefins such as ethylene is known (for example, Japanese Patent Publication No. 44
-20621 Publication, Special Publication No. 49-24593,
(Special Publication No. 49-12589, etc.).

Improving the rigidity of polypropylene is a common problem for propylene homopolymers and copolymers with other α-olefins, and there are methods for this purpose, such as adding various nucleating agents. Some are known.

In addition, examples of using a polymer nucleating agent as a method for preventing the used nucleating agent from bleeding from the molded product are known (for example, Japanese Patent Laid-Open No. 60-139710, Japanese Patent Laid-Open No. 60-13
9731, etc.).

[The problem that the invention is trying to solve]

The method of using a polymer nucleating agent not only prevents bleeding but also has the effect of greatly improving the rigidity and transparency when made into a film or sheet. However, the method using a polymer nucleating agent
Generally, vinyl cyclohexane or the like is polymerized on a solid catalyst, and then propylene is polymerized as a catalyst covered with a polymer nucleating agent by washing etc., or on a solid catalyst,
There is a method in which propylene is directly polymerized by treatment with vinyl cyclohexane or the like. In the former case, the activity per solid catalyst is significantly reduced, and the boiling n-
There were problems such as the percentage of heptane extraction residue (hereinafter abbreviated as Nl) decreased significantly, and when the obtained polymer was made into a molded product, the appearance of the molded product was poor. On the other hand, in the case of the latter, the above-mentioned problem of decreased activity and NI does not substantially occur during batch polymerization, but when polymerization is carried out for a long time such as continuous polymerization, there is a problem that the polymerization activity and NI decrease significantly. there were.

(Means for Solving the Problems) The present inventors have intensively studied methods for solving the above problems, and have completed the present invention.

That is, the present invention provides a) a solid catalyst comprising a titanium halide supported on a carrier containing magnesium halide on at least its surface; b) two or more trialkylaluminum or two or more bonded to each other through oxygen or nitrogen atoms. C) a stereoregularity improver selected from esters, ethers, orthoesters, alkoxy silicon compounds, and d) a halogen-containing organoaluminum compound. In the method of polymerizing α-olefin, a) a solid catalyst is prepared in advance;
C) Part to all of the stereoregularity improver, d) Part to all of the halogen-containing organoaluminum compound, and b) 0 to part of the organoaluminum compound, in an inert hydrocarbon solvent, are mixed with alkylvinylsilane or alkyl This continuous propylene polymerization method is characterized in that, after contact treatment with allylsilane, the treated mixture, the remainder of components C) and d), and component b) are introduced into a propylene polymerization zone.

In the present invention, a) many examples of the solid catalyst are already known, including a solid catalyst formed by supporting titanium halide on a carrier containing magnesium halide, which provides polypropylene with high activity and high stereoregularity. For example, a carrier may be co-pulverized with various organic compounds (preferably oxygen-containing organic compounds) and magnesium halide, and then titanium tetrachloride, titanium acid chloride, or the like may be mixed with various solvents. A method in which magnesium halide is solubilized in a hydrocarbon solvent such as ether, alcohol, or amide, or in a halogenated hydrocarbon solvent, and then dissolved in an oxygen-containing organic solvent using a precipitant such as titanium halide or silicon halide. A method in which magnesium halide is precipitated by treatment in the presence or absence of a compound, etc., and then used as a carrier with or without contact with an oxygen-containing organic compound, etc., to support titanium halide in the same manner as described above, organic magnesium alcohol,
Contact treatment is carried out with alkoxy silicon, and then the obtained solid component is further contacted with a halogen-containing compound and then used as a carrier with or without contact treatment with an oxygen-containing organic compound, and titanium halide is supported in the same manner as described above. For example, there is a method in which a solid is precipitated from a solution of a magnesium compound as described above, in which an inert solid such as alumina or silica is present to prepare a carrier, and then a titanium halide is supported on the carrier.

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

In the present invention, as component b), trialkylaluminum such as trimethylaluminum, triethylaluminum, tripropylaluminum, triisobutylaluminum, trihexylaluminum, or a mixture thereof, or the above-mentioned trialkylaluminum and water according to a known method, Compounds obtained by reaction with ammonia or primary amines, such as (CzHs)zAl-0-AI(CzHs)z, (Ct
Hs) 2AI-N-AI (C1Hs) z, etc.

In the present invention, the esters, ethers, orthoesters, and alkoxysilicone compounds that are component C) include:
Specifically, esters such as ethyl acetate, methyl acrylate, methyl methacrylate, ethyl benzoate, methyl toluate, triethyl phosphate, triphenyl phosphate,
Ethers such as diethyl ether, diisoamyl ether, diphenyl ether, dinaphthyl ether, methyl orthoformate, ethyl orthoformate, methyl orthoacetate,
Examples include ortho esters such as methyl orthobenzoate and ethyl orthobenzoate, and alkoxy silicones such as tetraethoxysilane, triethoxyethylsilane, triethoxyphenylsilane, tritoxyphenylsilane, and trimethoxyvinylsilane.

In the present invention, examples of the halogen-containing organoaluminum compound as component d) include diethylaluminum chloride, diethylaluminum bromide, diethylaluminium iodide, dimethylaluminum chloride, dipropylaluminum chloride, dipropylaluminium bromide, diethylaluminum sesquichloride, diethyl aluminum Examples include aluminum sesquibromide, dipropylaluminum sesquichloride, ethylaluminum dichloride, propylaluminum dichloride, and dialkylaluminum halide is particularly preferably used.

Examples of the alkylvinylsilane or alkylarylsilane used in the present invention include trimethylallylsilane, trimethylvinylsilane, triethylvinylsilane, triethylallylsilane, dimethylethylallylsilane, dimethylethylvinylsilane, methyldiethylallylsilane, and methyldiethylvinylsilane, particularly trimethylvinylsilane and trimethylallylsilane. (hereinafter abbreviated as silane compound) can be preferably used.
.

In the present invention, the contact treatment with the silane compound prior to propylene polymerization is carried out in an inert hydrocarbon medium such as pentane, hexane, heptane, nonane, decane, cyclohexane, benzene, toluene, xylene, ethylbenzene, etc. , usually 0 to 70°C, preferably 10 to
It is carried out at 60°C.

The contact time is generally several minutes to several hours, and the concentration of the vinyl compound is generally 0.1 to 100 g/1. Preferably, the vinyl compound is 0 per solid
．． Reaction temperature and reaction time for polymerization 001 to 200 times by weight,
This is carried out under conditions of liquid phase concentration of the vinyl compound. What is important here is that the amounts used in the propylene polymerization of each of the above components a), b), C) and d) are as follows:
Component is the whole amount, C) component is part to whole amount, d) component is part to the whole amount.
The total amount of component b) is 0 to part used for contact with the silane compound prior to propylene polymerization, preferably component b) is 0 to 10%, component C) is 5 to 100%, b)
) component is 20 to 100%, particularly preferably component b) is 0%, component C) is 10 to 100%, and b) is 50 to 1%.
Use 00%. During contact treatment with a silane compound, b
If a large amount of component (C) is used, or if the amount of component (C) is too small, the activity may decrease during propylene polymerization or NI
On the other hand, if the amount of component b) used is too small, it not only causes a decrease in Nl during propylene polymerization, but also almost eliminates the effect of the vinyl compound polymerization prior to propylene polymerization. Put it away.

This treatment is preferably carried out batchwise.

In the present invention, propylene polymerization is continuously carried out by continuously introducing the above-mentioned catalyst into the propylene polymerization zone.

The conditions for the propylene polymerization zone may be any of solvent polymerization, bulk polymerization, and gas phase polymerization, and the polymerization temperature is 0 to 90°C, preferably 30 to 80°C, and the polymerization pressure is normal. Boat fishing is carried out at a pressure of ~50 kg/cnl.

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 regulator such as hydrogen can be used during the polymerization of the vinyl compound prior to the polymerization of propylene or during the polymerization of propylene.

〔Example〕

The present invention will be explained below with reference to Examples.

Experimental Example 1 Manufacture of homogeneous catalyst ■ A vibratory mill equipped with four crushing bores each having an internal volume of 41 and containing 9 kg of steel balls each having a diameter of 12 mm is prepared. 30.0 g of magnesium chloride, 60 ml of tetraethoxysilane and 45 ml of α,α,α-trichlorotoluene were added to each pot under a nitrogen atmosphere, and the mixture was ground for 40 hours.

3 kg of the above pulverized material, 1 ml of titanium tetrachloride, and 10 l of toluene were added to a reactor No. 501, and after stirring at 80° C. for 1 hour, the operation of separating by standing and removing the supernatant was performed twice.
The solid content was then diluted with 151 g of n-hebutane to obtain % solid catalyst A. This solid catalyst component contains 1.6 tX of titanium.
It contained.

Experimental Example 2 Production of Solid Catalyst 2 31.2-ethylhexyl alcohol 2.81, 2.81 kerosene, 276 ml of ethyl benzoate and 570 g of magnesium chloride were placed in the reactor 101, stirred at 130°C for 1 hour to form a homogeneous solution, and the reaction of 501 was carried out. Transfer the above homogeneous solution to a container,
After cooling to -20°C and charging 121 titanium tetrachloride over 1 hour, the temperature was raised to 90°C over 2 hours to precipitate a solid catalyst, and the mixture was further treated at 90°C for 2 hours. After that, the supernatant was removed by static separation, and titanium tetrachloride 1
212 was added and heat-treated at 80°C for 1 hour.Then, the solid content was separated by standing and the supernatant was removed.
Solid catalyst B was obtained by washing with No. 1 seven times. This solid catalyst component contained 2.5 wt.chi. of titanium.

Example 1 30 g of solid catalyst A obtained in the above experimental example, 213 ml of diethylaluminum chloride, 2 methyl p-)luino9ate
0111L 200ml of trimethylallylsilane and 11ml of n-hebutane were added, and the mixture was stirred at 40°C for 2 hours. A sample was taken and the amount of trimethylallylsilane polymerized per solid catalyst was analyzed and was found to be 0.3 g/g.
Met.

After putting 75 kg of propylene into an autoclave with an internal volume of 5002 and raising the temperature to 75°C, the hydrogen concentration was 3°5N.
Hydrogen was charged so that β was then used as a solid catalyst, and the above mixed slurry was used as a solid catalyst at 2.5 g/hSp -) Methyl Ruilate 41! +l/h and triethylaluminum 7m
1/h, liquefied propylene was charged at 75 kg/h, and slurry was extracted at 75 kg/h while hydrogen was introduced so that the hydrogen concentration in the gas phase became 3.5111. Polymerization was continued for 15 hours at °C.

Powder taken out from the slurry 10 hours after the start of polymerization was analyzed. The results are shown in Table-1.

The yield of polypropylene per solid catalyst is calculated from the titanium content in the powder, the intrinsic viscosity is 135℃ tetralin solution, and the percentage of boiling n-hebutane extraction residue is extracted for 6 hours with a pre-type extractor. It was calculated by The melting point and crystallization temperature were measured at 10°C using a differential scanning calorimeter.
The temperature was measured by increasing or decreasing the temperature by /win.

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

Example 2 The same procedure as in Example 1 was carried out except that solid catalyst B was used as the solid catalyst and vinyltrimethylsilane was used instead of allyltrimethylsilane. The polymerized amount of vinyltrimethylsilane was 0.2 g/g solid catalyst.

The results are shown in Table-1.

Example 3 The same procedure as Example 1 was carried out except that dimethylethylallylsilane was used in place of allyltrimethylsilane. Display the results -
Shown in 1.

Comparative Example 2 The same procedure as Example 2 was carried out except that vinyltrimethylsilane was not used. The results are shown in Table-1.

Comparative Example 3 The entire amount of all the components added during propylene polymerization was used in the first stage of contact, and when introducing the autoclave into the autoclave for propylene polymerization, the nozzle was set as a double tube, and the treated catalyst was charged from the inner tube. Moreover, by charging n-hebutane to the outside, clogging of the catalyst charging nozzle was prevented and polymerization was carried out. The results are shown in Table-1.

〔Effect of the invention〕

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

[Brief explanation of drawings]

FIG. 1 is a flow chart diagram of a catalyst used for continuous polymerization of propylene.

Claims (1)

[Claims] a) a solid medium comprising titanium halide supported on a carrier containing magnesium halide at least on its surface; b) trialkylaluminum or an organic material having two or more aluminum atoms bonded to each other via oxygen or nitrogen atoms. Polymerizing propylene or propylene and other α-olefins using a catalyst consisting of an aluminum compound, c) a stereoregularity improver selected from esters, ethers, orthoesters, and alkoxy silicon compounds, and d) a halogen-containing organoaluminum compound. In the method, in advance, a) solid medium, c) part to all of the stereoregularity improver, d) part to all of the halogen-containing organoaluminum compound, and b) 0 to part of the organoaluminum compound are mixed with inert carbon. Continuous polymerization of propylene, characterized in that after contact treatment with an alkylvinylsilane or alkylarylsilane in a hydrogenated solvent, the treated mixture, the remainder of components c) and d), and component b) are introduced into a propylene polymerization zone. Method.