JPS642124B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [1] Background Technical Field of the Invention The present invention relates to a method for producing an olefin polymer using a so-called Ziegler type catalyst.

According to the present invention, a method for producing an olefin polymer using a new Ziegler type catalyst is provided. This catalyst has high activity, and the olefin polymer obtained has a high degree of stereoregularity, and the particle size distribution of the polymer powder is extremely good.

PRIOR ART It has been known for a long time to produce olefin polymers using a catalyst consisting of a combination of a titanium halide compound and an organoaluminum compound. It was proposed in the 1970s to be used on a carrier such as magnesium halide.
This is discussed in the invention described in Publication No. 12105.

Furthermore, according to Japanese Patent Publication No. 46-7583, it has been reported that a complex obtained by reducing titanium tetrachloride with a Grignard reagent also has high activity, and the magnesium halide contained in this complex is It is understood that it also exerts a cocatalytic effect to improve the activity of .

The composite of magnesium halide and titanium halide compound can be synthesized by various methods, but when combined with an organoaluminum compound to polymerize olefins, especially propylene, it exhibits excellent effects in terms of polymerization activity. However, since the stereoregularity of the produced olefin polymer is extremely low, it has almost no practical value as a catalyst for producing olefin polymers as it is.

On the other hand, it has been widely considered to modify a catalyst formed by combining a titanium halogen compound and an organoaluminum compound and add a third component to these catalyst components in order to improve the stereoregularity of the produced olefin polymer. Among these, a method using organic acid esters, especially α,β-unsaturated carboxylic acid esters such as ethyl benzoate, p-ethyl toluate, and p-ethyl anisate, is a method that is particularly effective as a third component. No. 46-12140, No. 46-21731,
It is known from Publication No. 47-25706, etc.

It is also being considered to obtain a catalyst that combines these two types of prior art, ie, a catalyst consisting of a magnesium halide, a titanium halide compound, an organic third component, and an organoaluminium compound.
However, the olefin polymer produced using such a catalyst has sufficiently high catalyst activity and stereoregularity, and the process of decomposing and removing the catalyst after the polymerization operation can be omitted or simplified, reducing its production cost. However, in reality, no technology has yet been provided that can fully satisfy the above-mentioned problems.

In addition, the halogen atoms in titanium halogen compounds conventionally used as catalyst components have strong acidity, and the resulting olefin polymer is resistant to equipment used in post-processing steps such as granulation and molding after polymerization. Based on the well-established theory that the lower the concentration of halogen atoms in the produced olefin polymer is, the more corrosive it is, and that the active center during polymerization is the titanium compound. Efforts have been made only to reduce the concentration of halogen atoms in the resulting olefin polymer by increasing the coalescence yield.

However, in addition to the titanium halogen compound, the catalyst contains more halogen atoms derived from the magnesium halide used as a carrier or co-catalyst, and the halogen atoms derived from the magnesium halide are present in the produced olefin polymer. dozens
It usually contains from ppm to several hundred ppm, and has an impact that cannot be ignored.

That is, although the halogen atom in the titanium halogen compound has strong acidity, it is possible to obtain hundreds of thousands of grams of olefin polymer for every gram of titanium atom contained in the catalyst. The content of halogen atoms in the produced olefin polymer is also on the order of several ppm, and it is considered that whether or not to remove this is not a very important issue.

Rather, the magnesium halides, especially magnesium chloride, contained in the catalyst are widely known as one of the most effective corrosive agents for iron, and like titanium halogen compounds, the halogen atoms remain in the resulting olefin polymer. It is a compound that is undesirable.

However, in the past, most of the catalyst composition was made up of magnesium halide, and the fact that the halogen atoms derived from this were actually much larger in quantity was often ignored.

Therefore, in order to achieve a non-deashing production process, it is necessary to increase the yield of olefin polymer based on all the halogen atoms contained in the catalyst, in other words, the yield of olefin polymer per titanium atom as well as the yield of olefin polymer per magnesium halide. It is understood that it is an essential issue to greatly improve the coalescence yield.

Although some attempts have been made in the prior art to improve the yield of olefin polymer per magnesium halide, no noteworthy effects have been achieved. For example, in JP-A No. 16986-16986, Na ₂ CO ₃ and CaSO ₄ are used;
In Publication No. 151691, B ₂ O ₃ is added during the grinding process. However, the simple incorporation of such a heterogeneous carrier with the intention of reducing the halogen content in the catalyst only causes a decrease in the yield of olefin polymer per titanium atom and a decrease in stereoregularity, and does not have a positive improvement effect. can not see. The reason for this is that Ziegler-type catalysts made of titanium and aluminum compounds are extremely sensitive to poisoning, and if oxygen-containing compounds such as those in the example above are used without special consideration, they will immediately become poisonous components and reduce the effectiveness of the catalyst. It is understood that this is to weaken it.

Furthermore, conventionally, in the method of producing an olefin polymer using a highly active catalyst, particularly in the method of using magnesium halide as a catalyst carrier, the magnesium halide serving as the catalyst carrier is activated mainly by pulverization. Therefore, it is inevitable that the finished catalyst will also have an irregular shape and a wide particle size distribution. The polyolefin powder produced for this purpose is generally amorphous and fine powder, and has a wide particle size distribution. Industrially, such a polymer containing a large amount of fine powder has the drawback that it is difficult to completely separate the polymer and the polymerization solvent from the slurry solution after polymerization, and the recovery rate of the polymer cannot be sufficiently increased. Furthermore, when producing an ethylene-propylene copolymer, there is also the drawback that it is not easy to obtain a copolymer with a sufficiently large bulk density. Furthermore, when it comes to polymer fine powder of about 100 microns or less, the presence of a large amount of it tends to cause a dust explosion when handling dry powder. Further, when molding the powder as it is, there is a risk of dust explosion, and problems such as a decrease in efficiency during molding occur. Furthermore, even in a gas phase polymerization method that does not use any solvent, there are major constraints on industrialization in terms of uniformity of the fluid state, recovery of polymer powder, transportation of powder, etc. Ideally, it is desired that there be no fine powder of about 100 μm or less.

However, when using conventional catalysts that are activated through the pulverization process, the proportion of fine particles of less than 100 μ usually accounts for 10 to 30%, and often reaches 40%, which is a big problem in industrial implementation. It is becoming. There are ways to solve this problem, but for example, in the invention described in JP-A-53-109587, the amount of fine powder of 105μ or less is only about 8%, and there is still room for improvement. There is.

For olefin polymer powder, its shape,
It is well known that the size is similar to the shape and size of the catalyst that produces it (for example,
Written by J. Boor, Jr. Ziegler―Natta Catalysts
and Polymerizations, p.154, Academic Press
Company. Published in 1979). Therefore, the particle shape of the olefin polymer can be improved by improving the shape of the catalyst used to produce it. Specifically, in order to eliminate fine polymer powder, catalyst fine powder must be eliminated. This is a problem that is difficult to solve because it is a requirement that is often contradictory to increasing polymerization activity. Particularly in catalysts that undergo pulverization, a wide particle size distribution is an unavoidable phenomenon and poses an extremely difficult problem.

[2] Summary of the invention The purpose of the present invention is to provide a solution to the above-mentioned points, and the present invention aims to provide a solution to the above-mentioned points by treating it with a titanium compound represented by the general formula Ti(OR) ₄ (where R is a hydrocarbon residue). By using a metal oxide support, it is possible to prevent a decrease in polymerization activity and stereoregularity due to the support, and to produce MgX ₂ (here, X is a halogen), TiCl ₄ without pulverization.
By supporting ester and ester, the above object could be achieved.

Therefore, the method for producing an olefin polymer according to the present invention includes (1) silica, alumina, magnesia, treated with a titanium compound represented by the general formula Ti(OR) ₄ (where R is a hydrocarbon residue); Metal oxides containing titania or their double oxides,
It is characterized in that olefin is brought into contact with a catalyst consisting of MgX ₂ (where X is a halogen), a solid catalyst component supporting TiCl ₄ and an ester, and (2) an organoaluminum compound for polymerization.

Effects According to the catalyst system of the present invention, compared to conventionally known catalysts, the yield of olefin polymer per halogen atom in the catalyst, specifically, the yield of olefin polymer per halogen atom in the catalyst, specifically per magnesium halide, which constitutes the majority of the halogen, is increased. Not only does it have a high yield of olefin polymer and maintains high stereoregularity, but the resulting olefin polymer powder has a narrow particle size distribution, containing almost no fine powder of about 100μ or less, and has an extremely high bulk density. . Therefore, there is no risk of dust explosion in the currently widely used slurry polymerization process, and post-polymerization post-treatment steps are greatly simplified or even eliminated. Separation of the polymer also becomes easier. It also facilitates the production of copolymers.
Even in gas phase polymerization processes that do not use any solvents, the fluidized bed can be easily stabilized, allowing powder recovery and
Transportation becomes easier. Further, even in the non-granulation molding method expected in the future, problems such as reduction in efficiency and generation of dust will be eliminated, and efficiency can be increased.

These characteristics can be easily understood from the fact that when the solid catalyst component is observed under an electron microscope, there is no fine powder smaller than 20μ, and the average particle size is about 60μ. Furthermore, the characteristic X-ray image shows that magnesium and titanium are evenly distributed on the carrier, suggesting the effect of their supporting. In addition, the X-ray diffraction image is completely amorphous, unlike that of the magnesium halide carrier.
This indicates that the active catalyst component is almost completely amorphous, that is, activated, due to the influence of amorphous silica. In addition, the specific surface area of the solid catalyst component is almost
It is 300m ² /g or more, often 400m ² /g, which indicates good dispersion. Therefore, the catalyst of the present invention has excellent activity, stereoregularity, and particle size distribution in any of slurry polymerization, liquid phase non-solvent polymerization, and gas phase polymerization processes.

[3] Specific description of the invention 1 Catalyst component (solid component) This is a transition metal component of the Ziegler catalyst, and is a titanium compound represented by the general formula Ti(OR) ₄ (where R is a hydrocarbon residue). MgX ₂ (where X is halogen) on a metal oxide support treated with
It supports TiCl ₄ and ester.

(1) Components It is composed of the following components (a) to (d).

(a) Metal oxide support Basically consists of a metal oxide or a mixed oxide selected from silica, alumina, silica-alumina, magnesia, titania, or a mixture thereof.

Basically, it is desirable to use an anhydride, but a trace amount of hydroxide is usually allowed.
Furthermore, the inclusion of impurities within 10% by weight, preferably within 6% of the total weight, is included within the scope of the support of the present invention as long as it does not significantly alter the characteristics as a metal oxide. Examples of permissible impurities include metal oxides such as sodium oxide, potassium oxide, calcium oxide, zinc oxide, nickel oxide, cobalt oxide, sodium carbonate, potassium carbonate, magnesium carbonate, sodium sulfate, aluminum sulfate, titanium sulfate, nitric acid. Examples include carbonates, sulfates, and nitrates such as aluminum and magnesium nitrate.

In order to prevent poisoning as much as possible, it is desirable to use carriers that are fired at high temperatures and stored in an inert gas atmosphere. The shape is powder
It is preferable that the crystallinity is low so that the line diffraction image is wide or amorphous. A material with a large specific surface area is also desirable. The carrier is used in the subsequent processing in powder form, and since the particle size of the powder is related to the particle size of the obtained olefin polymer powder, it is desirable that it can be adjusted as appropriate. Although the pore volume and average pore diameter of the carrier powder are not very important factors in the present invention, larger ones are preferable.

Treatment with titanium compounds of the general formula Ti(OR) ₄ These metal oxide supports are used prior to other operations to prepare catalysts that give high polymer yields and stereoregularity per titanium atom. General formula Ti
It is essential to treat metal oxides with titanium compounds represented by (OR) ₄ . Here, R is a hydrocarbon residue, generally an alkyl group having 1 to 10 carbon atoms, preferably 1 to 4 carbon atoms, or an alkyl group having 4 to 10 carbon atoms.
, preferably a cycloalkyl group having 5 to 8 carbon atoms, or an aryl group having 6 to 10 carbon atoms, preferably phenyl, tolyl or xylyl.

Specific examples of such compounds include Ti(O—iC ₃ H ₇ ) ₄ , Ti(O—nC ₃ H ₇ ) ₄ , Ti(O—
Examples include nC ₄ H ₉ ) ₄ Ti(O-iC ₄ H ₉ ) ₄ and Ti(OC ₆ H ₅ ) ₄ .

Among them, Ti(O—nC ₄ H ₉ ) ₄ is preferred.

Any known method may be used to treat metal oxides with these titanium compounds. For example, in the case of a solution or liquid compound, the metal oxide can be contacted in the form of a slurry. The titanium compound may be contacted as a high temperature vapor. In addition, mechanical contact can also be achieved by means such as co-pulverization. Warming is not required, but is generally effective in speeding up the process. Specifically, the temperature range is 0°C to 400°C, preferably 30°C to 200°C, particularly preferably 50°C to 150°C.

(b) Magnesium halide (MgX ₂ ) Magnesium halides include magnesium chloride, magnesium bromide, magnesium fluoride,
Examples include magnesium monochloride and magnesium monobromide, but magnesium chloride is particularly good. Each of them may be used alone, or as a mixture or composite.

(c) Ester An electron-donating organic compound is used as the ester.

Among these compounds, esters of organic acids, more preferably esters of α,β-unsaturated carboxylic acids, especially monocarboxylic acids, especially esters with monohydric alcohols are preferred. The definition of "α,β-unsaturation" includes aromatic unsaturation in addition to ethylenic unsaturation.

For example, benzoic acid lower alkyl ( _C1 - _C12 ) esters such as methyl and ethyl esters,
Lower alkyl P-toluate (e.g. ethyl)
esters, p-anisic acid lower alkyl (e.g. i-propyl) esters, methacrylic acid, lower alkyl (e.g. methyl) esters, acrylic acid lower alkyl (e.g. ethyl) esters, cinnamate lower alkyl (e.g. ethyl) esters,
Dilower alkyl maleate (e.g. dimethyl)
There are esters and others. Especially benzoic acid or p-
Lower alkyl esters of aromatic carboxylic acids such as toluic acid are preferred.

(d) Titanium halogen compound The titanium halogen compound used in the present invention is:
Titanium tetrachloride (TiCl ₄ ).

(2) Method for preparing solid components Effective catalyst components can be deposited and supported on the surface of an oxide carrier by the method described in Japanese Patent Application No. 54-94141. That is, the solid component is prepared by the following method.

Magnesium halide itself does not dissolve in titanium tetrachloride at all, but its complex with ester D (e.g. ethyl benzoate), MgX _2.nD , has n of approximately 0.8.
In the above cases, it dissolves easily.

The solution thus obtained exists as a mixture of the three components of titanium species, magnesium compound, and ester, and such magnesium halide does not play a role as a carrier. By bringing such a mixture into contact with a non-toxic metal oxide carrier and bonding it to the surface of the metal oxide carrier, an extremely useful catalyst component can be obtained.

Similarly, even if n is in the range of 0.2 to 0.8, if the amount of solids is set small relative to the solvent (titanium tetrachloride), or if partial dissolution is sufficient, then the performance of the final catalyst obtained You can see almost the same thing.

Under these conditions, at least not all the solids appear to dissolve, but in reality the dissolution-precipitation of a small amount of solids appears as a dynamic equilibrium state, and in the absence of another type of support As precipitation,
Magnesium halide, which is relatively large in quantitative proportion, serves as a carrier and a conventional catalyst is obtained.

Further details are provided below.

Synthesis of MgX ₂ nD The complex MgX ₂ nD is synthesized by contacting magnesium halide with the ester in advance (where n is 0.15 to 2.0, preferably 0.2 to
It is in the range of 0.5. ) This contact may be carried out by stirring the pulverized magnesium halide with the ester in slurry form in the presence or absence of a nonpolar solvent, or by stirring the pulverized magnesium halide with the ester while heating. It may be reacted with gasified ester at high temperature. It is also effective to carry out the reaction by co-pulverizing in a vibrating mill or the like. Co-milling can be carried out in milling equipment such as ball mills, vibratory mills, impact mills, etc. At this time, it is an effective, although not essential, measure to add a grinding aid to complete the ester reaction. Examples of these auxiliaries include titanium tetrachloride, silicon tetrachloride, polysiloxane, Ti(O-nC ₄ H ₉ ) ₄ , B
( _OC2H5 ) ₃ , Al( _{OC2H5 ) 3} , halogenated hydrocarbon _,
Examples include aromatic hydrocarbons. The auxiliary agent may be added from the beginning or during the grinding process.

Dissolution of MgX ₂ ·nD The thus obtained complex of MgX ₂ and ester is dissolved, and the titanium halogen compound itself, which is one of the catalysts of the present invention, has this function as the solvent used. However, it is also possible to dilute this with a certain amount of non-polar solvent. Preferred examples of non-polar solvents include halogenated hydrocarbons such as dichloroethane, dichloropropane, dichlorobutane, propyl chloride, chlorobenzene, dichlorobenzene, trichlorobenzene, propyl bromide, and ethyl iodide. It is possible to dilute by adding up to twice the volume (volume). In addition, aromatic hydrocarbons such as benzene and toluene can also be used, although the dilution ratio is lower, and hydrocarbons such as hexane, heptane, and cyclohexane can also be diluted to a small extent.

Dissolution of the complex is promoted by heating. The temperature range is 0°C to 250°C, preferably 30°C to 200°C, and particularly preferably 60°C to 150°C. Dissolution can be promoted by stirring.

Bonding to the metal oxide support Simply add the metal oxide support treated with a titanium compound represented by the general formula Ti(OR) ₄ (where R is a hydrocarbon residue) to the above solution and stir. The effective catalyst components are easily bound and supported almost quantitatively on the surface of the carrier. However, if n
In the case of partial dissolution of 0.15 to 0.3, it is not possible to sequentially solubilize and support the magnesium halide component and ester component, and an excellent particle size distribution is achieved by allowing the metal oxide carrier to coexist from the time of dissolution. This is an essential condition for obtaining a catalyst that gives . When the molar ratio is between 0.3 and 2.0, there is no problem in taking the same measures. Heating is not required but is effective in promoting binding. Also, cooling the solution after heating and before separating the solid portion from the solution is not essential, but it is an effective means. It is understood that this helps complete the bonding of the unsupported catalyst component with the oxide surface which is dissolved during heating.

It is thought that in this treatment stage, the magnesium halide complex is dissolved or colloidally dispersed and adsorbed or precipitated on the surface of the metal oxide, creating an effective supported state (a portion remains dissolved and is lost). . At the same time, it is considered that the active species Ti compound is supported and the ester is appropriately extracted.

The catalyst solid that has undergone the above bonding treatment is separated from the solution, washed, and used for polymerization.

(3) Quantitative ratio The quantitative ratio of the components (a) to (d) above may be any quantitative ratio as long as the effects of the present invention can be obtained, but in general, solid catalyst components composed of the following quantitative ratios are preferred. preferable.

(a) Metal oxide support 30 to 95% by weight, preferably 35 to 90% by weight (b) Magnesium halide 5 to 60% by weight, preferably 10 to 50% by weight (c) Ester 0.1 to 20% by weight, preferably 0.2 to 15% by weight (d) TiCl ₄ 2 to 30% by weight, preferably 4 to 20% by weight The composition of the finished catalyst of the solid catalyst component thus prepared is as follows.

(a) Metal oxides 30 to 90% by weight, preferably 35 to 80% by weight (b) Titanium (as atoms) 0.3 to 8% by weight, preferably 0.7 to 5% by weight (c) Magnesium (as atoms) 2 to 20% by weight % Preferably 3 to 15% by weight (d) Halogen (as atoms) 5 to 60% by weight Preferably 10 to 45% by weight (e) Ester 0.5 to 20% by weight Preferably 1 to 15% by weight 2 Catalyst component General formula AlRnX An organoaluminum compound represented by _3-o is used. Here, R is hydrogen, a hydrocarbon residue having 1 to 20 carbon atoms, especially an alkyl group, an aralkyl group, or an aryl group, X is a halogen, especially chlorine or bromine, and n satisfies 0<n≦3. The number is within the range. Specifically, (a) trimethylaluminum, triethylaluminum, triisobutylaluminum, trioctylaluminum,
Trialkyl aluminum such as tridecyl aluminum, (b) diethyl aluminum monochloride, diisobutyl aluminum monochloride,
Alkylaluminum halides such as ethylaluminum sesquichloride and ethylaluminum dichloride, alkylaluminum halides such as (iii) diisobutylaluminum halide, and others. Among these, trialkyl aluminum is particularly preferred. The amount of organoaluminum compound used is 0.01 to 0.01 to the weight ratio of the solid catalyst component.
200, preferably 0.03 to 100, but the range depends on the quantitative ratio of the catalyst components described below.

3. Other Catalyst Components The catalyst of the present invention basically consists of the above two components () and (), but other components may be added as necessary. For example, known electron-donating organic compounds such as alcohols, ethers, esters, ketones, and aldehydes may be added as the third catalyst component. It may be the same compound as used for solid component treatment or a different type of compound.
The appropriate amount to be used is in a molar ratio of 0 to 0.5, preferably 0 to 0.4, relative to the organoaluminum compound.

4 Polymerization of olefins (1) Olefins Olefins polymerized using the catalyst system of the present invention have the general formula R-CH=CH ₂ (where R is a hydrogen atom or a hydrocarbon residue having 1 to 10 carbon atoms, and a substituent is It is an α-olefin represented by Specifically, for example, ethylene, propylene, butene-1, pentene-1, 4-methyl-pentene-1
There are olefins such as Preference is given to ethylene or propylene, particularly preferably propylene.

It is also possible to use mixtures of α-olefins. For example, in the case of propylene polymerization, it is possible to copolymerize propylene with up to 20% by weight of other α-olefins (especially ethylene). Also, copolymerizable monomers other than the above α-olefin (e.g. vinyl acetate, diolefin)
It is also possible to perform copolymerization with.

(2) Polymerization The catalyst system of the present invention can be applied not only to ordinary slurry polymerization, but also to liquid-phase solvent-free polymerization or gas-phase polymerization that uses substantially no solvent, as well as continuous polymerization and batch-type polymerization. It can be applied to both polymerization and prepolymerization methods.

In the case of slurry polymerization, the solvent is hexane,
Saturated aliphatic or aromatic hydrocarbons such as heptane, cyclohexane, and toluene may be used alone or in mixtures. Polymerization temperature is from room temperature to about 200℃,
The temperature is preferably 50° to 150°C, and hydrogen can be added as a molecular weight regulator at this time.

Example 1 All of the following operations are performed under an inert gas atmosphere.

Preparation of metal oxide carrier Silica gel No. 951 manufactured by Fuji Davison Co., Ltd. (average particle size approximately 46 μm) was calcined at 500° C. for 5 hours and dried.
2g of this silica, Ti(O
Add 1.70 g of -nC ₄ H ₉ ) ₄ and 50 ml of dehydrated n-heptane, and heat and stir at 80°C for 5 hours. Then, remove the solution part and dry it.

Preparation of solid catalyst component 0.2 mol of anhydrous magnesium chloride and 0.07 mol of ethyl benzoate are sealed in a vibrating mill pot with an internal volume of 1, and pulverized for 24 hours to produce MgCl ₂ .0.35EB (EB represents ethyl benzoate). Then, an additional 0.07 mol of titanium tetrachloride was added to the pot, and the mixture was ground for another 24 hours.

Add 2 g of the silica treated above, 4.5 g of the above pulverized material, 20 ml of dehydrated 1,2-dichloroethane, and 100 ml of titanium tetrachloride into a 200 ml three-necked flask, and add 80 ml of titanium tetrachloride.
Heat and stir at ℃ for 2 hours. Then, stop heating and continue stirring until the temperature returns to room temperature. Then, remove the solution part and wash thoroughly with 1,2-dichloroethane and n-heptane.

Analysis of the solid catalyst component thus obtained contained 4.22% by weight of titanium, 8.05% by weight of magnesium, and 34.0% by weight of chlorine.

Polymerization of propylene Dehydrated industrial heptane in autoclave 1
Add 500 ml of the above solid catalyst component, 0.5 mg of the above solid catalyst component in terms of Ti atoms, 180 mg of triethylaluminum, and 86 mg of ethyl p-toluate, and reduce the propylene pressure to 1.
After prepolymerizing at room temperature for 15 minutes at Kg/cm ² G, hydrogen
Add 100ml, total propylene pressure 9Kg/cm ² G, 65℃
Polymerization was carried out for 90 minutes. As a result, 63
g of polypropylene is obtained, its II (boiling n
- Heptane extraction residual rate) was 93.8%, and MI (melt index) was 1.2. Polymerization activity is 126Kg
-Polymer/g-Titanium atoms, 16.8Kg-Polymer 1g-MgCl ₂ , 15.6Kg-Polymer/g-Chlorine atoms. The theoretical amount of chlorine remaining in this polymer corresponds to 64 ppm. Table 1 shows the particle size distribution of this powdered polypropylene. It is clear that there is an excellent distribution with very little fines.

Table 1 Weight ratio under sieve Polymer particle size Example 1 (wt%) 53μ or less 0.6 74 〃 1.3 105 〃 3.1 149 〃 10.5 297 〃 39.9 500 〃 80.8 840 〃 98.6 840μ or more 100.0 Example 2 Preparation of metal oxide support catalyst Manufactured by Kasei Kogyo Co., Ltd. Magnesium silicate (composition
3MgO.4SiO ₂ ) was fired at 500°C for 5 hours and dried. In a 200ml three-necked flask, 5g of this magnesium silicate, 0.50g of Ti (O-nC ₄ H ₉ ), 1,2-
Add 50 ml of dichloroethane and stir at room temperature for 1 hour. The solvent was then evaporated under vacuum at 50°C.
Heat and dry for 1 hour.

Preparation of solid catalyst components In a 200 ml three-necked flask, 2 g of magnesium silicate treated as described above, anhydrous magnesium chloride used in Example 1, 4.5 g of co-pulverized product of ethyl benzoate and titanium tetrachloride, 20 ml of 1,2-dichloroethane,
100 ml of titanium tetrachloride was added, treated under the same conditions as in Example 1, and washed.

Analysis of the solid catalyst component thus obtained revealed that it contained 3.43% by weight of titanium, 7.80% by weight of water-soluble magnesium, and 32.8% by weight of chlorine.

Polymerization of propylene Triethylaluminum in Example 1
Polymerization of propylene was carried out under exactly the same conditions as in Example 1 except that 143 mg of ethyl p-toluate and 61.6 mg of ethyl p-toluate were used. As a result, 82.2g including soluble content
of polypropylene was obtained, whose II was 92.3% and MI was 1.3. Polymerization activity is 164Kg-polymer/g-titanium atoms, 18.4Kg-polymer/g-
MgCl ₂ , 17.2Kg-polymer/g-chlorine atom. The theoretical amount of chlorine remaining in this polymer is
Equivalent to 58ppm. In this powdered polypropylene
The amount of fine powder polymer of 105μ or less was 2.5% by weight.

Example 3 In place of the co-pulverized product in Example 2, 4.8 g of a co-pulverized product which was pulverized with additional addition of 0.71 ml of Ti(O-nC ₄ H ₉ ) ₄ as a grinding aid was used. A solid catalyst component was prepared under exactly the same conditions as in Example 2. As a result, a solid catalyst component containing 3.52% by weight of titanium and 8.19% by weight of water-soluble magnesium was obtained.

When propylene was polymerized under the same conditions as in Example 2, 73.4 g of polypropylene including soluble content was obtained, with II of 93.4% and MI of 1.2. The polymerization activity was 147 Kg-polymer/g-titanium atoms and 16.1 Kg-polymer/g- _MgCl2 . The amount of fine powder polymer of 105μ or less in this powdered polypropylene was 2.9% by weight.

Example 4 Instead of Ti(O-nC ₄ H ₉ ) ₄ in Example 1
Example 1 except that 1.42g of Ti(O-iC ₃ H ₇ ) ₄ was used.
When the solid catalyst components were adjusted under exactly the same conditions, titanium was 4.51% by weight and magnesium was 8.02% by weight.
A solid catalyst component was obtained.

When propylene was polymerized under the same conditions as in Example 1, 59 g of polypropylene including soluble content was obtained, with II of 91.9% and MI of 1.4. The polymerization activity was 118 Kg-polymer/g-titanium atoms and 16.9 Kg-polymer/g- _MgCl2 .
This powdered polypropylene contained 3.3% by weight of finely divided polymers having a particle size of 105μ or less.

Example 5 Powdered alumina manufactured by Japan Catalysis Society (JRC-ALO-
2. After firing the particles (average particle size 60μ) at 500℃ for 5 hours,
A solid catalyst component was prepared using 2.75 g of Ti(O-nC ₄ H ₉ ) ₄ under the same conditions as in Example 1. As a result, a solid catalyst component containing 4.26% by weight of titanium and 8.10% by weight of magnesium was obtained.

When propylene was polymerized under the same conditions as in Example 1, 53.7 g of polypropylene including the soluble content was obtained, with II of 93.6% and MI of 1.5.
It was hot. The polymerization activity was 107 Kg-polymer/g-titanium atoms and 14.4 Kg-polymer/g- _MgCl2 . The amount of fine powder polymer of 105μ or less in this powdered polypropylene was 4.1% by weight.

[Brief explanation of drawings]

FIG. 1 is a flowchart to help understand the technical contents of the present invention regarding Ziegler catalysts.

Claims (1)

[Claims] 1 Contains silica, alumina, magnesia, titania, or their double oxides treated with a titanium compound represented by the general formula Ti(OR) ₄ (where R is a hydrocarbon residue) In metal oxide, MgX ₂
(wherein X is a halogen), a solid catalyst component supporting TiCl ₄ and an ester, and an organoaluminum compound.