JPS6160085B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention is directed to a process for the polymerization of ethylene or alpha-olefins that produces polymers with improved particle size distribution. Ethylene using Ziegler type catalyst, or α
- Polymerization or copolymerization of olefins is known. The most common Ziegler type catalyst is composed of a catalyst component containing a titanium compound and an organoaluminum compound component. Furthermore, it is also known that catalytic performance is improved by using a pulverized catalyst component containing a titanium compound. The present invention relates to the polymerization of ethylene or α-olefins using a Ziegler type catalyst consisting of a specially pulverized titanium catalyst component and an organoaluminum compound. In the conventional method of pulverizing the titanium catalyst component using a ball mill or the like, the resulting pulverized product has a wide particle size distribution, and usually contains fine particles of 5 microns or less.
Contains more than 10% by weight. In the polymerization or copolymerization of ethylene or α-olefins using a polymerization catalyst consisting of a catalyst component containing a titanium compound and an organoaluminum compound, the particle size of the produced polymer or copolymer depends on the titanium catalyst component used. Significantly affected by particle size. Since the titanium catalyst component pulverized by the conventional method contains a large amount of fine particles, the polymer or copolymer obtained using it also has a wide particle size distribution, and usually contains fine powder of 50 microns or less.
Contains 30% by weight. When producing polyethylene or polyα-olefin, the particle size distribution of the produced polymer is wide, especially if there are many fine powders, it becomes difficult to separate the produced polymer from the solvent by filtration or centrifugation, and there is also a large amount of loss due to dissipation. The same applies to the drying process and pelletizing process. Therefore, in order to prevent these problems, it is necessary to provide extra equipment and perform complicated manufacturing operations, and therefore, improvements are desired. A method for improving the particle size of pulverized titanium catalyst components is
Some have already been proposed. For example, a method of co-pulverizing titanium trichloride or a titanium trichloride composition by adding a small amount of organic ether or a complex of it and a metal halide (Japanese Patent Publication No. 1973-
3024, Japanese Patent Publication No. 43-10065, etc.), when solid magnesium compounds such as magnesium halides and titanium tetrachloride or titanium trichloride are co-pulverized to support those titanium compounds on the solid surface,
A method of co-pulverization by adding a small amount of organic ethers and a complex of aluminum halide or polysiloxane (Japanese Patent Application No. 35136/1983, Japanese Patent Application No. 1983-1999)
21777). In these methods, agglomeration and agglomeration occur simultaneously with atomization through the pulverization operation, and the particle size of the pulverized product is improved, with the number of fine particles having a diameter of 5 microns or less being reduced to about several percent by weight. However, when such pulverized products are used in polymerization reactions, they may be suspended in a solvent and redispersed into fine particles by charging into a polymerization machine using a pump or stirring during polymerization. Therefore, it has the disadvantage that fine polymers or copolymers are produced and the particle size distribution becomes wide. The purpose of the present invention is to provide extremely low content of fine powder.
producing polymers or copolymers with narrow particle size distribution;
An object of the present invention is to provide a method for polymerizing ethylene or α-olefins. A feature of the polymerization method according to the present invention is that a small amount of ethylene or α-
It is obtained by adding olefin and co-pulverizing it with an organoaluminum compound represented by the general formula AlR _n X _3-n (where R is alkyl or aryl, X is hydrogen or halogen, and m is 1 to 3). The purpose is to use a Ziegler type catalyst consisting of a titanium component and an organoaluminum compound component. The starting titanium catalyst component is titanium trichloride or a composition thereof, or titanium tetrachloride, titanium trichloride, or a composition thereof supported on the surface of a solid support. What is titanium trichloride or titanium trichloride composition?
Titanium trichloride obtained by reducing titanium tetrachloride with hydrogen, a eutectic of titanium trichloride and a metal halide obtained by reducing titanium tetrachloride with a metal, and a compound of titanium tetrachloride having an Si-H bond, It also means titanium trichloride or all titanium trichloride compositions containing titanium trichloride as a main component, such as titanium trichloride compositions obtained by reduction with organoaluminum compounds. Further, as the solid carrier for supporting titanium tetrachloride or the above-mentioned titanium trichloride or titanium trichloride composition, a wide range of materials can be used, including silica, alumina, silica/alumina, boron oxide, and magnesium compounds, and there are no particular limitations. However, magnesium compounds, particularly magnesium halides, are preferred. In order to support the above-mentioned titanium compound on these solid carriers, methods such as mixing and co-pulverizing the two or subjecting the two to a heating reaction in the presence or absence of a solvent are usually carried out. The abovementioned starting materials can advantageously be subjected to the subsequent co-pulverization, in particular by being pulverized beforehand. General formula AlR _n X _3-n used in co-grinding
The organoaluminum compound (R,
Examples include triisobutylaluminum, diethylaluminum monochloride, diisobutylaluminum monochloride, diisopropylaluminum monochloride, diethylaluminium monobromide, and ethylaluminum sesquichloride. The amount used is preferably in the range of 0.01 to 100 mol per 1 atom of titanium in the starting material. This organoaluminum compound may be added when the starting material is pulverized in advance. The amount of ethylene or α-olefin added in co-grinding is about 10% by weight or less based on the starting material, and the upper limit is usually about 0.01% by weight. As the α-olefin, lower α-olefins such as propylene and butene-1 are used. These need not be the same type of monomers that are polymerized in the presence of the catalyst. The conditions and operation for co-pulverization are detailed in Japanese Patent Application No. 55423/1983, entitled Process for Producing Polymerization Catalyst Component, filed simultaneously on May 17, 1975. The titanium catalyst component prepared as described above contains fine particles with a diameter of 5 μm or less in an amount of several percent by weight or less. This is because during the co-pulverization of the starting titanium raw material and the organoaluminum compound, atomization and agglomeration occur simultaneously, and at the same time, a very small amount of polyolefin is produced by the polymerization of coexisting ethylene or α-olefin, which forms a type of linkage. It is thought that this prevents re-dispersion and atomization of the titanium component particles that have become agglomerated. The organoaluminum compound, which is another catalyst component used in the method of the present invention, has the same general formula as that used in the preparation of the titanium catalyst component described above.
A compound represented by AlR _n X _3-n (wherein R, Although the ratio of the titanium catalyst component to the organoaluminum compound component used in the method of the present invention can be varied over a wide range, it is generally preferred that the molar ratio of the organoaluminum compound component to the titanium catalyst component is about 1 to 500. The method of the present invention involves not only homopolymerization of ethylene and α-olefins, but also copolymerization of these monomers, such as ethylene and propylene, butene-
It also includes copolymers of 1, pentene-1, hexene-1, 4-methylpentene-1, propylene and butene-1, hexene-1, and the like. For the polymerization reaction according to the method of the present invention, conventional methods and conditions commonly used in the art can be employed. The polymerization temperature at that time is 20 to 300℃, preferably 50℃.
-200°C, and the polymerization pressure is in the range of normal pressure to 200 atm, preferably in the range of normal pressure to 150 atm. In polymerization reactions, aliphatic, cycloaliphatic, aromatic hydrocarbons, or mixtures thereof, can generally be used as solvents, such as propane, butane, pentane, hexane, heptane, cyclohexane, benzene, toluene, etc. Mixtures thereof are preferably used. It is also possible to perform bulk polymerization using the liquid monomer itself as a solvent. Furthermore, it can also be carried out under conditions in which a solvent is substantially absent, that is, by a so-called gas phase polymerization method in which a gaseous monomer and a catalyst are brought into contact. The molecular weight of the polymer produced in the method of the present invention varies depending on the reaction mode, catalyst system, and polymerization conditions, but can be controlled by, for example, adding hydrogen, alkyl halide, dialkylzinc, etc., as necessary. I can do it. According to the present invention, a polymer or copolymer with a narrow particle size distribution and an extremely low fine powder content can be obtained. The present invention will be explained below using examples. Production example of titanium component 1 30 g of titanium trichloride obtained by reducing titanium tetrachloride with hydrogen at high temperature was placed in a bottle with an internal volume of about 1 containing 100 steel balls with a diameter of 12 mm in a nitrogen stream.
Vibratory mill grinding for 30 hours. Then diethyl aluminum monochloride 0.3
ml was added and ground for 5 minutes, and while continuing grinding, 200 ml of propylene was charged over 4 hours. The fine particle content of titanium trichloride thus obtained was measured using the method shown below, and the result was 3.4wt%.
It was hot. The pulverized titanium trichloride was placed in a standpipe purged with nitrogen, and nitrogen gas was passed from the bottom to the top at a rate of 0.7 cm/sec for 15 hours. As a result, the fine particles overflowing from the standpipe were collected in a dust collector connected thereto, and expressed as the ratio of the above collected amount to the charged amount, which was taken as the fine particle content of the pulverized product. Polymerization of propylene was carried out using the above particle size-adjusted titanium trichloride. Example 1 1000 ml of heptane, 1.2 g of titanium trichloride for particle size adjustment, and 2.0 ml of diethylaluminium monochloride were placed in a SUS-32 autoclave having an internal volume of 2 under a nitrogen atmosphere. After replacing the autoclave with propylene,
Hydrogen was charged to a partial pressure of 0.5 Kg/cm ² . While stirring the contents of the autoclave, heat the autoclave and raise the internal temperature to 70℃ after 5 minutes.
Polymerization was continued. During the polymerization, propylene was continuously injected to maintain the internal pressure at 5 kg/cm ² gauge. After 4 hours of polymerization, charging of propylene was stopped, and 300 ml of methanol was added to separate the catalyst, yielding 483 g of polymer. The boiling n-heptane extraction residue (abbreviated below) of the obtained polymer was 82.3%, the intrinsic viscosity was 1.83, and the bulk specific gravity was 0.42 g/
ml, and the activity of the polymerization reaction was 101 g/g-Ticl ₃ composition hr (hereinafter abbreviated as g/g-cat.hr). Results of sifting the obtained polymer powder through a 200mesh sieve and measuring fine particles of 200mesh or less
It was 9.3wt%. Comparative Example 1 Titanium trichloride obtained by hydrogen reduction of titanium tetrachloride at high temperature in the method of Titanium Component Production Example 1 was simply ground for 34 hours to produce fine particles of titanium trichloride in the same manner as in Titanium Component Production Example 1. The result was 18.3wt%. When polymerization was carried out in the same manner as in Example 1 using this titanium trichloride, the resulting polymer was 80.3
%, intrinsic viscosity number 1.73, bulk specific gravity 0.38g/ml,
28.7% of fine particles less than 200mesh, polymerization activity is 83
g/g-cat.hr. Titanium component production example 2 Titanium tetrachloride is reduced with aluminum powder in the presence of aluminum chloride, and its composition is approximately
A eutectic of Ticl ₃ and 1/3 Alcl ₃ was obtained. This eutectic
After pulverizing 30 g for 30 hours in the same manner as in Titanium Component Production Example 1, it was further treated in the same manner using 0.3 ml of diethylaluminum monochloride and 100 ml of ethylene. Similarly, fine particles were measured and found to be 3.7%. Example 2 Polymerization was carried out in the same manner as in Example 1 using 0.6 g of this particle size-adjusted titanium trichloride and 1.2 ml of diethylaluminum monochloride. The resulting polymer is 91.1%, with an intrinsic viscosity of 1.68,
The bulk specific gravity was 0.43, the fine particles of 200 mesh or less were 7.8 wt%, and the polymerization activity was 265 g/g-cat.hr. Comparative Example 2 A titanium trichloride eutectic obtained by reducing with metal aluminum in the same manner as in Titanium Component Production Example 2 was simply
34hr crushed. The percentage of fine particles measured in the same manner was 21.3%. When polymerization was carried out in the same manner as in Example 2 using this titanium trichloride, the resulting polymer was 88.9
%, intrinsic viscosity number 1.68, bulk specific gravity 0.41g/ml,
Fine particles of 200 mesh or less accounted for 23.4%. The polymerization activity was 232 g/g-cat.hr. Titanium component production example 3 In the method of titanium component production example 2, the olefin used for particle size adjustment was replaced with ethylene and 200ml was used.
The same procedure was carried out except that butene-1 was used, and the amount of titanium trichloride fine particles was 4.3%. Example 3 Polypropylene obtained by polymerization using the above titanium component had a content of 90.8%, an intrinsic viscosity of 1.77, a bulk specific gravity of 0.42, and 8.3% of fine particles of 200 mesh or less.
The activity in the main polymerization reaction was 235 g/g-eat.hr. Titanium component production example 4 Anhydrous magnesium chloride 29.4g, titanium tetrachloride
0.6g in a vibrating mill in the same way as titanium component production example 1.
After grinding for 20 hours, add 0.3ml of triisobutylaluminum and continue grinding while adding 50g of ethylene/
hr rate for 4 hours to produce a particle-sized titanium composition. When the fine particles were measured in the same manner, it was found to be 5.0 wt%. Example 4 Ethylene polymerization was carried out according to the method of Example 1 using the above titanium composition and triisobutylaluminum as a catalyst.
The following fine particles were 3.8%. Comparative Example 3 When the particle size adjustment using ethylene was not carried out in the method of Example 4, the fine particles of the pulverized titanium composition was 18.7%, and the proportion of fine particles of 200 mesh or less in the produced polyethylene was 15.3%. Comparative Examples 4 to 6 Catalysts were prepared by repeating the same experiment in the method of Titanium Component Production Example 2 by varying the amount of ethylene added during co-pulverization. The results are shown in the table.

[Table] Table 2 shows the results of polymerization using the catalysts prepared in Comparative Examples _4A and _5A . In the case of Comparative Example 5, the number of fine particles of the catalyst component was reduced, but block-like substances were formed in the pulverized material, and the bulk specific gravity was decreased.The same was true for the polymer polymerized using this, and the shape of titanium trichloride was poor. It is thought that it has become.

【table】

Claims (1)

[Claims] 1. Titanium trichloride, a titanium trichloride composition, or a composition in which titanium tetrachloride is supported on magnesium halide, to which a small amount of about 10% by weight or less of ethylene or α-olefin is added. Then, the general formula
AlR _n X _3-n (where R represents an alkyl group or an aryl group, X represents hydrogen or halogen, m
is 1 to 3) A method for producing a catalyst component for polymerizing ethylene or α-olefins, the method comprising co-pulverizing the catalyst component with an organoaluminum compound represented by formula (1 to 3). 2. The method for producing a catalyst component according to claim 1, wherein titanium trichloride, a titanium trichloride composition, or a composition in which titanium tetrachloride is supported on magnesium halide is pulverized in advance. 3. The method for producing a catalyst component according to claim 1, wherein the ethylene or α-olefin is added in an amount of about 0.01 to 10% by weight.