JPH041208A - Solid catalyst component for production of polyethylene - Google Patents

Abstract

PURPOSE:To obtain the title component which can give polyethylene having a low fine powder content and an excellent particle size distribution in high yield by bringing a specified suspension into contact with TiCl4 and an aliphatic ketone at low temperature, heating the obtained mixture, and further treating with the obtained composition with TiCl4. CONSTITUTION:A suspension obtained by bringing diethoxymagnesium into contact with dichloroethane is brought into contact with TiCl4 and an aliphatic ketone (e.g. 2,6-dimethyl-4-heptanone) at 0 deg.C or below, and the temperature of the mixture is raised over a period of at least 3hr. The mixture is treated at 70-130 deg.C, and the obtained composition is further treated with TiCl4 to obtain a solid catalyst component for the production of polyethylene. When polyethylene is produced by using this solid catalyst component, the influence of chlorine on the formed polymer can be decreased to such an extent that no deashing process is necessary, and the persistence of the activity during polymerization is excellent so that the component is not aged during a long-time polymerization reaction. Especially, polyethylene having a low fine powder content and an excellent particle size distribution can be obtained in high yield.

Description

Detailed Description of the Invention [Industrial Field of Application] The present invention provides a high-performance solid that, when subjected to ethylene polymerization, can produce polyethylene with a high yield and less fine powder and an excellent particle size distribution. Regarding medium components.

[Prior Art] Conventionally, polyethylene has been widely used in pipes, fuel containers, food packaging films, agricultural films and sheets, shopping bags, garbage bags, daily necessities, miscellaneous goods, and the like.

In order to produce such polyethylene, a so-called Ziegler catalyst, which is a combination of a solid catalyst component containing a transition metal component and an organoaluminum compound, has been used. As the solid catalyst component containing the above transition metal component,
It has been generally known that titanium trichloride catalyst components and magnesium-supported titanium-based solid catalyst components are used.

[Problems to be Solved by the Invention] Conventionally known titanium trichloride catalyst components are used in the production of polyethylene in combination with diethylaluminum chloride, but the yield of polymer per unit catalyst or unit transition metal is low. (hereinafter referred to as catalytic activity), there is a large amount of catalyst residue in the produced ethylene polymer. Therefore, a so-called deashing step for removing the residual catalyst contained in the obtained polymer and decolorizing it was inevitable. This deashing process uses large amounts of alcohol or chelating agents, so recovery equipment for them is essential, and resources and
There were many energy and other related problems, and it was an important problem for those skilled in the art to urgently solve.

For this reason, in recent years, many proposals have been made in which a magnesium-supported titanium-based solid catalyst component is used in combination with an alkyl aluminum. However, although these known catalysts are excellent in that the catalytic activity per unit transition metal is improved, the catalytic activity per unit catalyst including the support is still insufficient in many cases.

Regarding the catalyst activity, it is preferable not only to have a high polymer yield per unit transition metal, but also to have a high polymer yield per unit catalyst from the viewpoint of process operation and manufacturing cost. Furthermore, as disclosed in Japanese Patent Publication Nos. 63-43407 and 63-49686, it is possible to use magnesium chloride as the magnesium-supported titanium-based solid catalyst component and use a titanium halide as the active component. It has become the mainstream of configuration requirements. The chlorine contained in this magnesium chloride has the disadvantage of having an adverse effect on the produced copolymer, similar to the chlorine in titanium halides.
For this purpose, there were unresolved issues such as requiring high activity to the extent that the influence of chlorine can be virtually ignored, or the need to keep the concentration of magnesium chloride itself low.

In addition, these known solid catalyst components become fine when they come into contact with the organoaluminum used during polymerization, and as a result, a large amount of polymer fine powder is generated, which causes problems in process operation.
The problem of causing phenomena such as plugging remained. In order to prevent such atomization of the solid catalyst component, a method is known in which organoaluminium and ethylene are brought into preliminary contact with the solid catalyst component, as disclosed in Japanese Patent Publication No. 1-53885. However, there still remained the problem of the need to add additional equipment and the high costs associated with its operation.

[Means for Solving the Problems] The present inventors have conducted intensive research to develop a solid catalyst component for polyethylene production that can solve the problems remaining in the conventional technology, and as a result, they have arrived at this invention. This is what we propose.

That is, the feature of the present invention is that a suspension obtained by contacting (a) jetoxymagnesium with (b) dichloroethane is mixed with (c) titanium tetrachloride and (d) aliphatic After contact with ketones, 3
A solid catalyst component for producing polyethylene is provided by increasing the temperature over a period of time, performing treatment at 70° C. or higher and 130° C. or lower, and further adding (c) titanium tetrachloride to the resulting composition. It's there.

The (d) aliphatic ketones (hereinafter simply referred to as (d) substance) used in the present invention include acetone, 2
-butanone, 3-methyl-2-butanone, 3,3-dimethyl-2-butanone, 2-pentanone, 3-pentanone, 4-methyl-2-pentanone, 2,4-dimethyl-3
-pentanone, 2-hexanone, 3-hexanone, 2-
Methyl-3-hexanone, 3-methyl-2-hexanone, 5-methyl-2-hexanone, 5-methyl-3-hexanone, 25-dimethyl-3-hexanone, 2-heptanone, 3-heptanone, 4-heptanone, 2-methyl-
3-heptanone, 2-methyl-4-heptanone, 5-methyl-3-heptanone, 6-methyl-2-heptanone,
2.6-dimethyl 4-heptanone, 2-octanone, 3
Examples include -octanone, 4-octanone, 2-nonanone, 3-nonanone, 4-nonanone, 5-nonanone, 2-decanone, 3-decanone, 4-decanone, and the like.

The solid catalyst component obtained in the present invention constitutes a polyethylene production catalyst when used in combination with an organoaluminum compound. The organoaluminum compound used in this case is: - Ship's RnA I
It is expressed as Specific examples include triethylaluminum, triisobutylaluminum, diethylaluminum chloride, and ethylaluminum sesquichloride, but it is also possible to use a mixture of these.

As the raw material (a) di-engineered toximagsium (hereinafter sometimes simply referred to as (a) substance) used in the present invention, it is preferable to use one that is dried under reduced pressure and then further pulverized under an inert atmosphere. It is.

When obtaining the solid component in the present invention, (a) substance, (b
) dichloroethane (hereinafter sometimes simply referred to as (b) substance), (c) titanium tetrachloride (hereinafter simply referred to as (c) substance), and (d) substance in the following order: (a) substance and ( b) After contacting the substances to form a suspension, it is necessary to contact the substances (c) and (d) under stirring. However, (a) a substance and (b) a suspension consisting of a substance, (c) a substance and (d)
Regarding the contact of substances, it is not prohibited to carry out the contact in any order as long as the effect of the present invention is recognized, but the contact temperature is 0 ° C.
It is necessary that the following is true. After contact with each of the above substances,
The temperature is gradually increased over 3 hours while avoiding temperature rise due to rapid reaction, and the final treatment temperature is 70℃ or higher and 130℃.
The temperature must be below ℃. Contact time is 5 minutes or more,
Preferably it is in the range of 30 minutes or more and 100 hours or less. At this time, if the contact temperature is less than 70°C, the reaction will not proceed sufficiently, and if it is higher than 130°C, evaporation of the solvent, decomposition of the materials used, etc. will become noticeable, making it difficult to control the reaction.

The substance (b) used in the present invention is used in a ratio of 1 or more, preferably 5 or more, per 1 g of the substance (a). (c) The substance is (a) For 1 g of the substance,
It is used in a ratio of 1 or more, preferably 5 or more.

(d) The usage rate of the substance is: (a) 1g of the substance
0.01 to 5, preferably 0.05
- or more and 2 or less.

In addition, during or after contact with each of the above substances,
As diluents it is also possible to use hydrocarbon solvents such as hexane, heptane, octane, decane, benzene, toluene, xylene, etc.

Repeat c) on the solid product obtained as above.
The contact temperature when bringing substances into contact is usually 70°C or higher13
The temperature is preferably 0°C or lower, the contact time is 5 minutes or more,
Preferably, the time is in the range of 30 minutes or more and 1°0 hours or less. The ratio of the substance (c) used in this case is usually 1 or more, preferably 5 or more, per 1 g of the substance (a). It is also possible to use a hydrocarbon solvent such as hexane, heptane, octane, decane, benzene, toluene, xylene, etc. as a diluent during or after the contact of each of the above substances. It is also possible to roughly wash the obtained composition using an organic solvent such as heptane.

All of these aspects are included in one aspect of implementing the present invention.

The solid catalyst component produced as described above is combined with the organoaluminum compound to form a catalyst for producing polyethylene. The organoaluminum compound used is used in a molar ratio of 1 to 1000 based on the mole of titanium atoms in the catalyst component. Usually, polymerization is carried out in a hydrocarbon or halogenated hydrocarbon solvent, and the polymerization temperature is 0 to 150'.
C. The polymerization pressure is 0 to 100 kg/am/·G. At this time, hydrogen can be used as an auxiliary molecular weight regulator, and if necessary, electron-donating compounds such as esters, ketones, amines, and silicon compounds having Si-〇-〇 bonds may be added. It is also possible to use it as

[Operations and Effects of the Invention] When polyethylene is produced using the solid catalyst component obtained by the present invention, the catalytic activity is extremely high, so that the amount of chlorine in the produced polymer is reduced to such an extent that no deashing step is required. The impact can be reduced. Furthermore, since the activity during polymerization is excellent in sustainability, it also has the advantage of being less likely to deteriorate during polymerization reactions that require a long time. Furthermore, the present invention is characterized in that it provides a solid catalyst component that can be used to produce polyethylene with less fine powder and excellent particle size distribution without pretreatment with organoaluminium and ethylene. . In addition, when the solvent component is removed from the solid catalyst component to form a powder, almost no particle aggregation is observed, resulting in additional effects such as cost reduction in process operations and equipment in the catalyst preparation process. It also plays.

[Examples and Comparative Examples] The present invention will be specifically explained below using Examples and Comparative Examples.

Example 1 <Crushing of jetoxymagnesium> 30 g of jetoxymagnesium was charged into a stainless steel vibration mill having an internal volume of IQ and having 50 balls of 25 mm in diameter, which was sufficiently purged with nitrogen gas, and pulverized for 24 hours.

<Preparation of solid catalyst component> 5 g of jetoxymagnesium and 8 o's of 1,2-dichloroethane ground as above were charged into a 200 o' capacity round-bottomed flask equipped with a stirrer, making sure to sufficiently replace the mixture with nitrogen gas. 20 Or-p-m in titanium tetrachloride at 0°C placed in a 500-capacity round-bottomed flask equipped with a stirrer.
The mixture was added by pumping while stirring. Then 0
26-Simethyl-4-heptanone 1.5- at °C
After adding, the temperature was raised to 90°C over 3 hours, and the mixture was reacted for 2 hours while stirring. Thereafter, it was washed three times with 100- toluene at 90"C, the supernatant liquid was removed, 80- toluene and 2o- titanium tetrachloride were added, and the mixture was washed again at 1
The reaction was carried out at 10°C for 2 hours. Finally, a solid catalyst component was obtained by washing 10 times with 200% of 40"C n-hebutane. The titanium content in this solid catalyst component was 5.1
% by weight.

<Polymerization> A stainless steel autoclave with an internal volume of 1,500 d and a stirring device that was completely replaced with ethylene gas was charged with 700 mm of n-hebutane, and 1.0 mmoR of triethylaluminum was charged while keeping the autoclave in an ethylene gas atmosphere at 20°C. I entered. Then, after raising the temperature to 70°C, the solid catalyst component was charged as titanium atoms with O, O1mmof+, and the pressure in the system was immediately increased to 4kg/c! Charge hydrogen so that it is l/・G, and further supply ethylene to raise the total pressure to 6 kg.
/ant-G, the temperature was raised to 70°C, and polymerization was carried out for 2 hours. The pressure that decreased as the polymerization proceeded was compensated for by continuously feeding only ethylene, and the pressure was kept constant during the polymerization.

Ethylene was polymerized according to the above polymerization method, and the resulting polyethylene powder was filtered and dried under reduced pressure.
2g, and the polymer yield per 1g of catalyst at a polymerization time of 2 hours was 20,500g/g-cat. The bulk specific gravity of the obtained polymer was 0.28 g/d, and the average particle diameter expressed as 50% of the cumulative weight was 380 μm. In addition, the particle size expressed by 90% of the cumulative weight (D p
Particle size (DplO) expressed as 10% of cumulative weight from 90)
The value obtained by dividing the difference between the average particle diameter (D p 50) ((D p 9
When the spread of particle size distribution was evaluated using 0-DplO)7Dri50>, this value was 1.1. In addition, fine powder of 100 μm or less is 0. It was 5%.

Example 2 The amount of 2.6-dimethyl-4-heptanone used was 2.5-
The solid catalyst component was prepared and polymerized in the same manner as in Example 1 except that The results obtained are shown in Table 1.

Example 3 The mW of the solid catalyst component and the polymerization were carried out in the same manner as in Example 2 except that the amount of titanium tetrachloride used was 60. The results obtained are shown in Table 1.

Example 4 To 5 g of jetoxymagnesium, 80% of 1,2-dichloroethane was added, and 2.5% of 2,6-dimethyl-4-hebutanone was added to the resulting suspension. The solid catalyst component U8 was prepared and polymerized in the same manner as in Example 2, except that 100% of titanium chloride was added dropwise over 30 minutes with stirring. The results obtained are shown in Table 1.

Example 5 A solid catalyst component was prepared and polymerized in the same manner as in Example 1 except that 2-hexanone 1,5- was used as the aliphatic ketone. The results obtained are shown in Table 1.

Example 6 2-hebutanone as aliphatic ketone 1.5. A solid catalyst component was prepared and polymerized in the same manner as in Example 1 except that fJ was used. The results obtained are shown in Table 1.

Example 7 A solid catalyst component was prepared and polymerized in the same manner as in Example 1, except that 3-hebutanone 1,5- was used as the aliphatic ketone. The results obtained are shown in Table 1.

Comparative Example 1 Addition temperature of 2.6-dimethyl-4-heptanone to 30°C
A solid catalyst component was prepared and polymerized in the same manner as in Example 1 except that The results obtained are shown in Table 1.

Comparative Example 2 A solid catalyst component was prepared and polymerized in the same manner as in Example 1, except that the addition temperature of 26-dimethyl-4-heptanone was 70°C. The results obtained are shown in Table 1.

4,

[Brief explanation of the drawing]

The attached FIG. 1 is a flowchart relating to the preparation process of the solid catalyst component in the present invention.

Claims (1)

[Claims] (1) A suspension obtained by contacting (a) diethoxymagnesium with (b) dichloroethane is heated to (c
) titanium tetrachloride and (d) aliphatic ketone, the temperature is raised over 3 hours or more and the treatment is carried out at 70°C or higher and 130°C or lower, and the resulting composition is further treated with (c) titanium tetrachloride. A solid catalyst component for polyethylene production obtained by adding and processing.