JPS6088011A - Polymerization of olefin - Google Patents

Abstract

PURPOSE:To obtain a polyolefin in high yields per catalyst without any trouble due to coarse particles, by polymerizing the olefin in the presence of a catalyst comprising a Ti catalyst of a specified particle diameter and an organoaluminum compound. CONSTITUTION:A Ti catalyst is obtained by mixing a carrier obtained by copulverizing an Mg halide with a C-O bond-containing organic compound (e.g., ethyl o-acetate) in, for example, a ball mill with a liquid Ti halide (e.g., TiCl4) at 40-135 deg.C. A slurry formed by dispersing the catalyst in an inert hydrocarbon medium (e.g., hexane) is passed through a screening mesh having an opening smaller than R defined by the equation (wherein R0 is a slurry particle diameter limit for the process, d1 is a density of polyolefin, d2 is a density of the Ti catalyst, and w is an amount of the polyolefin formed per catalyst). A 3C or higher alpha-olefin is polymerized in the presence of a catalyst comprising the Ti catalyst and an organoaluminum compound (e.g., triethylaluminum).

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for polymerizing olefins using a specific titanium catalyst. More specifically, the present invention relates to an olefin polymerization method that does not cause process troubles due to coarse particles.

Various methods have been used to increase the yield of polyolefin using a catalyst since the invention of the Ziegler-Natsuta catalyst, but among them, the method of supporting titanium halide on a metal halide proposed in Japanese Patent Publication No. 39-12105 is a method to increase the yield of polyolefin using a catalyst. An effective method is to use a catalyst made of a catalyst obtained by the above method and an organoaluminum compound. In addition, many improvements have been proposed regarding this method, and catalyst performance has improved significantly over the past thousand years, with a catalyst boasting a high performance of 90,000 g per titanium catalyst/11-titanium catalyst being reported. There is.

Olefin polymerization is generally carried out in a slurry state in a liquid medium or a gaseous medium, since the viscosity of the solution is extremely high if the polymerization is carried out in a homogeneous solution state, and it is difficult to remove the p1 polymerization heat and transfer the solution. In this slurry polymerization, the polyolefin is present in the form of particles, but it is preferable that the particles are not huge or fine. In particular, if there are large particles, there is a problem that they may clog the narrow parts of equipment such as polymerization tanks and piping. This clogging problem is a serious problem in continuous production methods such as olefin polymerization, which can lead to the shutdown of the entire plant.The inventors have conducted various studies to solve the above problem. As a result, they discovered that this problem could be solved by using a titanium catalyst with special consideration given to its shape, and completed the present invention.

An object of the present invention is to provide a method for polymerizing olefins that is free from troubles caused by coarse polyolefin particles.

That is, the olefin polymerization method of the present invention is a method of co-pulverizing magnesium halide and an organic compound and polymerizing the olefin using a catalyst consisting of a titanium catalyst and an organoaluminum compound. This invention relates to a method for polymerizing olefins, which comprises passing a slurry in a hydrocarbon medium through a mesh sieve whose opening is smaller than R represented by the following formula [1].

Formula [l]: R = 2R, g publication■ In the formula, R11 is the critical slurry particle size of the process, d□ is the density of the polyolefin, d is the density of the titanium catalyst, and the production of polyolefin per W u f fi y catalyst. represents quantity.

Magnesium halides used in the present invention include magnesium chloride, magnesium bromide, and the like, with magnesium chloride being preferred.

Further, as the organic compound, various known metal compounds used in producing a magnesium halide carrier can be used, and among them, a C-O bond-containing compound is preferably used. Various known methods can be employed as the co-pulverization method, but co-pulverization using a ball mill or a vibration mill is particularly preferred.

The support thus obtained is then brought into contact with liquid titanium halide to produce a titanium catalyst. As the titanium halide used, titanium tetrachloride, which is liquid itself, is preferably used, but it can also be diluted with a hydrocarbon or the like, and solid titanium halide, such as titanium trichloride, can also be used in an appropriate medium. It is also possible to dissolve it and use it in liquid form. The contact is carried out in close contact using an appropriate stirring means, usually under heating at room temperature or higher, preferably at a temperature of 40 to 13
It is best to do this at 5°C. Many conditions for these contact conditions are already known.

In the present invention, the titanium catalyst obtained by the above treatment is passed in a slurry state in an inert hydrocarbon medium through a mesh sieve having a small opening in the radius R of the formula (1). As the inert hydrocarbon medium used in the present invention, aliphatic hydrocarbons such as hexane, heptane, and decane, aromatic hydrocarbons such as benzene, toluene, and xylene, or mixtures thereof are used.

The critical slurry particle size of the process R0 in formula [1] indicates the minimum diameter of coarse particles when the aforementioned various process problems occur due to the presence of coarse particles. In other words, when a certain trouble occurs, it is the minimum diameter of the coarse particles that are the cause. This varies depending on the details of the process, but cannot be determined, but when polymerization is carried out in a liquid medium slurry, 10 mn1
There must be no particles that exceed this value. Preferably 5III
It is better that particles exceeding I11 do not exist. In addition, in the gas phase medium slurry method, generally the permissible particle size of coarse particles becomes large, but it is better that particles exceeding the desperation Jlomm do not exist. Preferably, Ro is 5 mm or less.

Passage through the mesh sieve may be performed while applying appropriate vibrations so that the material passes under the action of gravity, but as this increases the amount of titanium catalyst that does not pass through, a method may be adopted in which the material is forcibly passed through with a brush and a spatula. Alternatively, the slurry may be passed under pressure using an autoclave.

The titanium catalyst thus obtained is combined with an organoaluminum compound and subjected to olefin polymerization. Examples of the organoaluminum compounds used in the present invention include trialkylaluminum, dialkylaluminum chloride, alkylaluminum sesquichloride, and alkylaluminum dichloride. There are various organoaluminum compounds available on the market.

Examples of olefins used in the present invention include ethylene, propylene, butene-1, hexene-1, etc., and homopolymerization or mutual copolymerization of these is carried out. Among them, α- The effect is great for olefins. That is, the polymerization method of the present invention does not cause any deterioration in catalyst performance, particularly the stereoregularity of the obtained polyolefin.

The method of the present invention makes it possible to produce polyolefins in high yields without any problems caused by coarse particles, and is therefore extremely valuable industrially.

EXAMPLES The present invention will be explained in more detail with reference to Examples below.

[Example, comparative example]

Predicted value of R The limit slurry particle size of propylene polymerization process is set to the normal value 5.
The density of titanium catalyst (actual value 2) was set as cod.
．． 2), and using a density of polynolopyrene of 0.9,
Furthermore, the normal value of W in this catalyst system is about 20,000'f.
:, were substituted into the above formulas, and approximate values were obtained.

= 0.274 (IllIn) This R value is taken as the standard, and a mesh sieve with an opening smaller than this (wire mesh with an opening of 0.147 m) and a mesh sieve with an opening even larger than this (wire mesh with an opening of 0.2') are used. Using a 95mm wire mesh),
The method of the invention was carried out.

Example 1, Comparative Example 1 a) Production of titanium catalyst 30 g of magnesium chloride containing 0.4 wt% water,
ethyl acetate 4.5%, 1,2-dichloroethane 3%
1Ll'! : Stainless steel pole 80 with a diameter of 12 wm
The mixture was placed in a pulverizing pot with an internal volume of 600 g, and pulverized for 40 hours. Next, the co-pulverized product was placed in a 3011 f 500-mm round bottom flask, and 15 titanium tetrachloride (ltA"i) was added.
Treatment under stirring at 0° C. for 1 hour and then 3QQmA! n-
After washing the solid portion with hebutane five times and extracting n-hebutane, 150 rIL of titanium tetrachloride was added and the mixture was heated at 80°C.
The mixture was treated with stirring for 1 hour. Then the solid part t30 Q
mA! The mixture was washed seven times with n-hebutane, and 150 + aA' of n-ethane was added to prepare a titanium catalyst slurry. Half of the amount was used as it was in the polymerization reaction (Comparative Example 1), and half of the amount was passed through a wire mesh with an opening of 0.147 m and used in the polymerization reaction (Example 1). The slurry was passed through a wire mesh by putting the slurry in a pressure-resistant container with a wire mesh at the bottom, pressurizing it, and allowing the slurry to pass through the wire mesh.

1) Polymerization reaction Prepare an autoclave with an internal volume of 5 tons that is sufficiently dried and purged with nitrogen. Add 5011 liters of n-heptane that has been dried and replaced with nitrogen into a 200-liter flask that has been thoroughly dried and replaced with nitrogen.
) Diethylaluminium chloride 0.128g, methyl toluate 0.0611Ll, ) diethylaluminium 0.081nl! 30m9' of titanium catalyst obtained in b)
ji-The added and mixed catalyst slurry was put into the Auto 7 Leve, and then 1.5 kg of propylene and 0.6 Nt of hydrogen were added and the Auto 7 Leve was heated.
After polymerization for a period of time, unreacted propylene was discharged, the resulting polypropylene/coudder was taken out, dried at 60° C. for 10 hours, and then weighed. This procedure was performed on the two types of titanium catalysts obtained in the above step). For each powder obtained, the intrinsic viscosity number (hereinafter abbreviated as η, measured in a tetralin solution at 135°C), boiling n-hebutane extraction residual rate (hereinafter abbreviated as II), extracted with boiling n-hebutane using a Nxhlet extractor,
The results of measuring the bulk specific gravity and particle size distribution (Tyler Metsea, USA) are shown in the table. As shown in the table, mouth opening 0.147
It can be seen that in the example using the titanium catalyst slurry passed through a wire mesh of wm, there were no polyolefin coarse particles having an opening of 4.7+u (ASTM standard Fluina 4) or more.

Example 2, Comparative Example 2 A titanium catalyst slurry was totally synthesized in the same manner as in Example 1, except that the additives used during co-pulverization were 5 m of cumene and 31 rLl of 1,2-dichloroethane. Example 2) The same procedure as in Example 1 was carried out except that half of the sample was passed through a 0.147 m wire mesh (Example 2). It can be seen that in the treatment using a 0.295 m wire mesh, there were coarse polyolefin particles of 4.7 cm or more.

Comparative Example 3 The same procedure as Comparative Example 1 was carried out, except that a glass stirrer was placed in the catalyst slurry of Comparative Example 1, and the slurry was vigorously stirred for 2 hours using a Star Two. The results are shown in the table.

Claims (2)

[Claims] (1) A method for polymerizing olefins using a titanium catalyst obtained by supporting titanium halide on a carrier obtained by co-pulverizing magnesium halide and an organic compound, and a catalyst consisting of an organoaluminum compound. A method for polymerizing olefins, characterized in that the titanium catalyst is used after being passed through a mesh sieve whose opening is expressed by the following formula and whose radius is small, in a slurry state in an inert hydrocarbon medium. Formula: In the formula, Ro represents the critical slurry particle size of the process, d□ represents the density of the polyolefin, d represents the density of the titanium catalyst, and w represents the amount of polyolefin produced per titanium catalyst. (2) The method for polymerizing oleinin according to claim (1), wherein the olefin is an α-olefin having 3 or more carbon atoms.