JPS60118703A - Polymerization of propylene - Google Patents

Abstract

PURPOSE:To carry out the polymerization of propylene effectively without causing the blocking of the pipings, and to remarkably improve the yield of PP per unit of the solid transition metal catalyst, by using a solid transition metal catalyst passed through a metal mesh having a specific mesh opening to separate coarse particles. CONSTITUTION:A solid transition metal catalyst (e.g. TiCl4, etc. supported on a carrier such as activated TiCl3, MgCl2, etc.) is dispersed in an inert hydrocarbon medium (e.g. hexane, heptane, benzene, xylene, etc.), and passed through a mesh having a mesh opening of 0.07-0.3mm.. A polypropylene is produced by polymerizing propylene in the presence of the catalyst prepared above under the polymerization condition (preferably normal temperature - 90 deg.C, and atmospheric pressure -50kg/cm<2>G). The weight ratio of the catalyst to the propylene is 1 to <=10,000. The filtration of the catalyst with the mesh is carried out by using a device having the stirring blades 2 furnished with a number of protrusions 3 toward the surface of the mesh 4, and the catalyst is passed through the mesh preferably after polymerizing 0.5-100g of propylene per 1g of the catalyst.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention I'! , relates to a method for polymerizing propylene. More specifically, the present invention relates to a polymerization method that provides a high yield per unit weight of a solid transition metal catalyst and is free from problems such as clogging of pipes.

Improvements in catalyst production methods have significantly increased the yield of polypropylene per solid transition metal catalyst.

Among them, the catalyst proposed in Japanese Patent Publication No. 39-12105, which is obtained by supporting a transition metal halide on a metal halide, not only greatly improves the yield of polypropylene per transition metal catalyst, but also improves the efficiency of subsequent catalysts. Improvements in production methods have significantly improved the yield per solid transition metal catalyst, including the support.

However, as the yield per solid transition metal catalyst has improved, the polypropylene particles obtained by polymerization have become larger than in the case of the prior art. The problem with polymer particles is 1.0% per gram of catalyst.
When obtaining polypropylene of 0.000q or more, various problems have arisen. That is, polyolefin polymerization is generally carried out in a slurry state in a liquid medium or a gaseous medium due to problems with solution viscosity and removal of polymerization heat. In polymerization in a slurry state, polyolefin exists in the form of particles, so it is preferable that there are no large or small particles, especially if there are large particles, they may get stuck in narrow parts of equipment such as polymerization tanks and piping. There was a problem of accumulation and blockage in some cases. This blockage is a serious problem in continuous production processes such as polyolefin polymerization, which can lead to the shutdown of the entire plant.

The present inventors have conducted intensive studies on methods to solve the above problems, and have used solid transition metal catalysts that have been subjected to specific treatments.
The inventors have discovered that the above problem can be solved by doing this, and have completed the present invention.

An object of the present invention is to provide a method for polymerizing propylene which is particularly free from troubles caused by coarse polypropylene particles.

When the transfer metal catalyst is dispersed in an inert hydrocarbon medium, the mesh opening is 0.3 mm (not smaller than 17 mm).
This invention relates to a method for polymerizing polypropylene, which is characterized in that it is used for polymerization after passing through gold-copper no larger than a straw.

In the present invention, the solid transition metal catalyst may be a known active form of titanium trichloride or a catalyst such as titanium chloride supported on a carrier such as magnesium chloride, and is not particularly limited. Applying a relatively difficult process of pulverization or co-pulverization to a catalyst that is included in the manufacturing process will improve its effectiveness. Alternatively, in the method of obtaining a carrier by precipitating a carrier raw material dissolved as a carrier, such as organomagnesium or magnesium halide complexed with alcohol, with an appropriate precipitant, particles of the solid transition metal catalyst obtained in the precipitation step are used. This problem is relatively small since it is possible to control the size of the particles fairly uniformly. However, solid transition metals produced by controlling the particle size as well as catalysts that include a grinding or co-grinding step in the catalyst manufacturing process. When introducing a catalyst into the process of continuously polymerizing propylene to obtain polypropylene, a small amount of propylene is added in advance to improve the stereoregularity or to increase the bulk specific gravity of the resulting polypropylene particles. Polymerize (
(hereinafter abbreviated as prepolymerization) (for example, Japanese Patent Publication No. 52-39871), the reason is not clear, but if polypropylene is obtained with a yield of 10,000 parts per gram of solid transition metal catalyst or higher, giant polypropylene is produced. Particles are a problem.

In the present invention, the above solid transition metal catalyst or prepolymerized solid transition metal catalyst is used in an inert hydrocarbon medium (e.g., aliphatic hydrocarbons such as hexane, heptane, decane, etc., aromatic hydrocarbons such as benzene, toluene, xylene, etc.). or a mixture of these is passed through the coat in a dispersed state. The opening of full-stage steel must be less than 0.07 mm and not larger than 0.3 mm; if it is less than this, it will not only be difficult to pass through, but also the resulting solid transition metal catalyst will not be used. If the polymerization is carried out in such a manner, the amount of fine polypropylene increases, which is undesirable.In addition, if the polymerization exceeds this point, it becomes impossible to eliminate the large particles of the catalyst.

When polypropylene is obtained by introducing a catalyst into the polymerization process after prepolymerization, it is actually more effective to perform the operation to pass the total rate of control after prepolymerization than to perform the operation before prepolymerization. It is true. This is because, as mentioned above, the prepolymerization operation generates a catalyst that causes giant particles.

For the above-mentioned operation of passing the gilt copper, it is preferable to use a device in which, for example, a part of the piping through which the dispersion of a common grain metal catalyst passes is provided with a stirring blade having a wire mesh facing the plane. This is because a blade with a large number of solid transects on the entire surface, such as a wire brush with metal wires embedded at intervals of several millimeters, fixed to the stirring shaft is sufficient, but the blades are not cut into the polymer. One method is to use a polypropylene resin because some of the resin may be mixed in and have a negative effect on the quality of the polypropylene product.

There are no particular limitations on the polymerization method using the solid transition metal catalyst thus obtained, and any known σ polymerization method can be employed. That is, a solvent polymerization method in which an inert hydrocarbon-like medium is used, a bulk polymerization method using one liquid propylene, or a gas phase polymerization method in which a liquid medium is substantially absent can be employed, and the polymerization temperature ( End of normal temperature ~ 90'C1 pressure is normal pressure ~ 5 a kg
It is a 7c gauge.

In the present invention, polypropylene includes not only the polymerization of propylene alone, but also ethylene, θ-random copolymers or block copolymers with other olefins such as ethylene-1 and hexene-1.

By using the method of the present invention, it is possible to efficiently produce polypropylene without problems caused by coarse particles, and industrially it is extremely easy to produce polypropylene.

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

Examples 1 and 2 Comparative Example 1 a) Production of titanium catalyst Moisture Q, 4 wt% of magnesium chloride 309, ol:/ethyl acetate 4. sw ], 2-dichloroethane 3
” It was placed in a grinding pot with an internal volume of 600 J containing 80 stainless steel balls with a diameter of 12 mm, and ground for 40 hours. The co-ground product 31 was then placed in a 500 ff!7 round bottom flask, and 150 d of titanium tetrachloride was mixed with υ ( "1 at 80℃
The mixture was treated with stirring for an hour, and then the solid portion was washed five times with 300 MlO) n-heptane, and after I]-hebutane was extracted, 150 g of titanium tetrachloride was added and the mixture was treated with stirring at 80 DEG C. for 1 hour. Furthermore, the solid part is 30 (n of 1-
- Washed with heptane 7 times and further washed with n-heptane 150 f.
d was added to form a solid transition metal catalyst slurry.

A part of the slurry was extracted and used as it was for the polymerization reaction (
Comparative Example 1\ Also, from the remainder, 10 ml was taken out as a solid transition metal catalyst and used for prepolymerization (Example Shio 4) By putting the slurry in a container and passing it through using differential pressure, it was possible to pass it efficiently.

(a) Prepolymerization A) This was carried out using the solid transition metal catalyst 109 obtained in a). I]-hebutane, which had been thoroughly dried and purged with nitrogen, was placed in an autoclave with an internal volume of 21. Diethylaluminum chloride 42°7ml 11) Methyl ruylate 20 - The above solid transition metal catalyst was charged as it was without using gold copper, and then 30ml of propylene was charged.

The internal temperature was maintained at 20° C. during the above operation.

(Prepolymerized slurry A) 13) Solid transition metal catalyst 5 obtained by passing through a wire mesh in a)
Prepolymerization was carried out in the same manner as in A) except that the amounts of the other substances were reduced to half by -4-. (Prepolymerization slurry 13
) C) Φ combination reaction thoroughly dried and replaced with nitrogen, with an internal volume of 51 mm).
Prepare the crepe (, 1ii-, l-. Thoroughly dry 2
This flask was dried and nitrogen-substituted +1-hebutane 50++17! and I)) Ethyl aluminum chloride 0.128m mixed with catalyst under each of the following conditions.
1° Methyl toluate ('1. ('1 (ifT4)) ethylaluminum (1, (18 ml) 30 ml of unfiltered solid transition metal catalyst (Comparative Example-j).

iI) diethylaluminum chloride O-128m,
30 ml of solid transition metal catalyst (Example 1-A) passed through 0.06 ml of methyl ruylate + 1 ethyl chloride and 0.08 d of gold.

1ii) Prepolymerization slurry IJ [30 mg as solid transition metal catalyst, triethyl aluminum +1, 08 m
l (actually 30mg) ethylaluminum 0,08
m1 (Example 2).

Using the catalyst slurries of I) to iV) above, each
The catalyst slurry was placed in an autoclave, and then 1.5 ml of propylene and 0.5 ml of hydrogen were added, and the autoclave was heated to conduct polymerization for 21 L'j at an internal temperature of 75°C. Next, unreacted propylene was removed from JJI, and the resulting polypropylene powder was taken out, dried at 60° C. for 10 hours, and then weighed.

Regarding the obtained powder, the intrinsic viscosity (hereinafter abbreviated as 1・-η, measured in a tetralin solution at 135°C) boiling n-II hepta/extraction residue (hereinafter abbreviated as ratio boiling I in a Soxhlet extractor) -hebutane for 6 hours The results of measuring the specific gravity and particle size distribution (Tyler mesh, USA) of the polymer before bulk extraction (calculated as extracted residual polymer weight - Xll''in%) are shown in the table.

[Brief explanation of drawings]

The drawing is a cross-sectional view of an example of a device for passing a catalyst equipped with a wire mesh used in the practice of the present invention. 1, Stirring motor 2, Protrusion stirring blade 3, Protrusion 4, Wire mesh 5, Solid transition metal catalyst inlet 6, Solid transition metal catalyst outlet Patent applicant: Mitsui Toatsu Chemical Co., Ltd.

Claims (1)

[Claims] 1) In a method for producing polypropylene under conditions in which 100,009 or more propylene is polymerized per 1 g of a solid transition metal catalyst, the solid transition metal catalyst is dispersed in an inert hydrocarbon medium and Polypropylene polymerization method characterized in that it is used for polymerization after passing through a wire mesh with an opening of not less than 0.07 mm and not larger than 0.3 mm. 2) 0.5 to 1009 propylene per 12 solid transition metal catalysts. The method according to claim 1, which comprises passing through a wire mesh after polymerization.