JPS5812283B2 - Ethylene diyugoutaino - Google Patents

Description

Detailed Description of the Invention CI) Background of the Invention The present invention provides (1) no polymer adhesion to the inner wall of the polymerization tank, stirring blades, etc., and therefore good polymer productivity;
) This relates to a method for producing an ethylene polymer with excellent powder properties (average particle size, particle size distribution, bulk density).

Disadvantages often arise when ethylene is polymerized using a catalyst consisting of an organometallic compound, such as diethylaluminum chloride, and a transition metal compound, such as titanium trichloride, which are generally referred to as Ziegler-type catalysts.

That is, a thin film of the polymer is formed on the inner wall of the polymerization tank, the stirring blade, etc., and the polymer is further strongly adhered to the thin film, resulting in the formation of lump-like polymer solids.

When such a phenomenon occurs, it not only significantly inhibits the heat transfer effect of the polymerization tank wall and makes it difficult to remove the generated polymerization heat, but also
The transportation path from the polymerization tank to the subsequent equipment is blocked, making it impossible to transport the polymer, and furthermore, the stirring efficiency in the polymerization tank is significantly reduced, making stirring virtually impossible.

Therefore, polymerization can be carried out virtually without polymer adhesion to the inner walls of the polymerization tank, stirring blades, etc., making it possible to carry out continuous polymerization over a long period of time using the same polymerization tank, improving polymer productivity. It is extremely important industrially to do so.

On the other hand, since ethylene polymers are produced by a so-called slurry polymerization method, the resulting polymers may have irregular particle sizes or too low bulk density.

That is, for example, if the average particle size is large or the particle sizes are uneven, pipes and valves may be clogged during polymer slurry transportation, and if the bulk density is low, the concentration of the polymer slurry may be increased. Since this method is not possible, it is necessary to increase the number of polymerization tanks, which is disadvantageous from an industrial perspective.

Therefore, the polymer particle size is 100μ or less and 100μ or less.
It is necessary that the number of particles having a diameter of 0 μ or more is as small as possible, and the bulk density is required to be as large as possible.

Therefore, it is extremely important industrially to have excellent powder properties (average particle size, particle size distribution, and bulk density of the polymer).

(■) Summary of the invention (Summary) The present invention aims to solve the above-mentioned problem of polymer adhesion to the inner wall of a polymerization tank and stirring blades, etc., and to produce an ethylene polymer with excellent powder properties. Among the compositions obtained by co-pulverizing titanium trichloride, a magnesium halide (MgX2: The aim is to achieve this objective by using the following.

Therefore, the method for producing an ethylene polymer according to the present invention is characterized by bringing ethylene into contact with a catalyst comprising a combination of component I) and component (2) below.

■) Solid composition obtained by mixing and pulverizing the following components (1) to (3): (1) titanium trichloride, (2) magnesium halide with a molar ratio of 3 or more to titanium trichloride, and (3) tetrachloride. Silicon or carbon tetrachloride ■) Organoaluminium compounds.

(Effects) In this way, the titanium compound component of the Ziegler catalyst used in this invention is a solid composition obtained by mixing and pulverizing titanium trichloride, a magnesium halide, and silicon tetrachloride or carbon tetrachloride. Of which, MgX2/T
If the molar ratio of iCl3 is 3 or more and this modified Ziegler catalyst is used, it is possible to prevent the polymer from adhering to the inner wall of the polymerization tank, stirring blades, etc.

If the solid composition obtained by mixing and pulverizing titanium trichloride, a magnesium halide, and silicon tetrachloride or carbon tetrachloride has a MgX2/TiCl3 molar ratio of 1 or less (Japanese Unexamined Patent Publication No. 47-39287), polymerization is not possible. A thin film of polymer was formed on the inner wall of the tank, the stirring blade, etc., and the polymer tended to adhere strongly to the thin film, resulting in the formation of lumpy polymerized solids. Of the mixed and pulverized solid composition, Mg X 2 / TiC (
It is unexpected that if a titanium compound having a molar ratio of 3 or more is used as a titanium compound component, the polymer will not adhere to the inner wall of the polymerization tank, stirring blades, etc.

This is because among the solid compositions obtained by mixing and pulverizing the two components of titanium trichloride and magnesium halide, M
g X2 / T iCl! When the molar ratio of 3 is 3 or less (see Japanese Patent Publication No. 47-462'69)
This is because, as far as the present inventors know, polymer adhesion to the inner wall of the polymerization tank, stirring blades, etc. cannot be eliminated.

The reason is that when silicon tetrachloride or carbon tetrachloride is added as a third component to titanium trichloride and magnesium halide, and the MgX2/Ticl3 molar ratio is 3 or more, the polymer does not adhere to the inner walls of the polymerization tank and stirring blades. Although it is not clear, it is inferred from the fact that the proportion of titanium that is solubilized in the polymerization solvent among the titanium contained in the solid composition obtained by mixing and pulverizing the three components that are considered to be the cause of polymer adhesion decreases. MgX 2 has a composition in which titanium trichloride and magnesium halide can form a stable complex different from the M gX 2 /T tCls molar ratio of 1 or less through silicon tetrachloride or carbon tetrachloride as the third component / T r Cl3 molar ratio 3 or more - 7
It is believed that there is.

Furthermore, the solid composition used in the present invention has powder properties, e.g., compared to a composition obtained by mixing and pulverizing two components of titanium trichloride and magnesium halide (see Japanese Patent Publication No. 47-46269). Ethylene polymers with excellent average particle size, particle size distribution, and bulk density can be obtained.

(IJ Specific description of the invention ■.Catalyst (1) Component■ Titanium trichloride Titanium trichloride includes titanium tetrachloride reduced with aluminum [TiCl3(A)], titanium tetrachloride reduced with hydrogen (
'rtcx3(H):), reduced with titanium (Ti
cl3(T)), those reduced with organoaluminum compounds (e.g. titanium trichloride by diethylaluminum chloride reduction), those reduced with silicon hydride compounds (
For example, titanium trichloride by hydromethylborisiloxane reduction), and many other types.

In the present invention, although the catalytic performance obtained is not necessarily the same (there may be a difference in catalytic activity depending on the type of titanium trichloride used), it can be used as the titanium trichloride component of the so-called Ziegler type catalyst. Therefore, this titanium trichloride does not have to be pure TI C4, for example Ti
Like C63(A), T t C l! For s /
3 moles of AlCl3 may be added, or such auxiliary components may be added afterwards, or a small amount of unreduced T I may be added, either unavoidably or purposefully.
It may contain Cl4, overreduced TiCl2, or an oxidation product of a reducing agent.

Magnesium halide MgX2 (X-halogen atom) Specifically, MgF2, MgCA2, MgBr2, Mg
■There are 2.

The amount ratio of silicon tetrachloride or carbon tetrachloride compounds (1) to (3) can be arbitrary as long as the effect of this invention is recognized, but usually the amount of magnesium halide (2) is: The amount of silicon tetrachloride or carbon tetrachloride is involved in polymer adhesion to the inner wall of the polymerization tank, stirring blades, etc., and is related to polymer adhesion and powder properties. It is determined in relation to the molecular weight distribution, particle size, morphology, and pulverization conditions of the polymer.

Each is as follows.

(1) The molar ratio of MgX2/T t Cls is 3 or more, preferably in the range of 10 to 50.

(2) Silicon tetrachloride or carbon tetrachloride is 0.1 to 50% by weight, preferably 1 to 20% by weight based on the total weight of the three components
, Mixing and Grinding The mixing and grinding of the three components (1) to (3) can be carried out using any grinding device that allows intimate contact between the three components.

Since mixing and pulverization should be carried out without coming into contact with moisture or air, various types of mills such as rotary ball mills, vibrating ball mills, rod mills, impact mills, etc. can be used as long as this point is taken into account.

The degree of mixed pulverization only needs to be sufficient to obtain the desired significant improvement effect of mixed pulverization of the three components (1) to (3). Therefore, from this point of view, the pulverization method, pulverization time, and pulverization conditions are determined. etc. should be selected.

In a vibratory ball mill, the time required to obtain the desired catalyst composition varies depending on the combination of various conditions such as ball filling rate, crushed sample filling rate, ball diameter, vibration frequency, width of the mill, and crushing temperature. It comes in eight, but generally it is one.
By grinding within 0.00 hours, a material with sufficiently improved catalytic performance can be obtained.

Those skilled in the art will also be able to easily find the optimum combination of these grinding conditions.

If necessary, pulverization can be carried out either wet or dry.

In a typical mixed grinding method, three components (1) to (3) are ground in a mixed state from the beginning regarding their types and amounts. It is also possible to add in portions.

(2) Component (2) Organoaluminum compound Although any component that can be used as a Ziegler type catalyst component for the polymerization of ethylene can be used, those represented by the following general formula are suitable.

AARnX3-n, A#Rn(OR')3-n where R and R' are the same or different hydrocarbon residues, X is a halogen atom, and n is 3, 2, 1.5 or 1.

Specifically, triethylaluminum, triisobutylaluminum, diethylaluminum chloride, diisopropylaluminum chloride, ethylaluminum dichloride, ethylaluminum sesquichloride,
Examples include diethyl ethoxide aluminum, and preferable results are obtained when trialkyl aluminum, specifically triethyl aluminum and triisobutyl aluminum, are used.

Quantitative Ratio The quantitative ratio of component 1) and component (2) is essentially the same as the quantitative ratio when component I) is ordinary titanium trichloride.

Depending on this quantitative ratio, slight changes in catalytic performance such as changes in catalytic activity may be observed, but in general, it can be used within the following range.

Component II)/Component I) 10, 1 to 100, preferably 1
~20 (weight ratio).

(3) It can be carried out in a manner essentially not different from that in the case where the catalyst preparation component I) is ordinary titanium trichloride.

That is, there are methods in which component I) and component (2) are mixed in advance in a polymerization solvent to form a catalyst and then fed into a polymerization vessel, or component I) and component (2) are directly fed into a reaction vessel separately to form a catalyst. There is a method of forming a catalyst simultaneously with the progress of the process.

It is known that various modifications can be made to Ziegler's catalyst, but in this invention, as long as the spirit thereof is not unduly impaired, components I) and n) and a mixture of components ) can be subjected to desired modifications such as heating, aging, washing, addition of components other than components I) and II) that improve catalyst performance, and other post-treatments.

2. The method of the present invention is essentially the same as the method for producing this type of ethylene polymer, except that the ethylene polymerization catalyst is as described above.

The catalyst of the present invention is of course applicable to ordinary slurry polymerization, but also to solvent-free polymerization which substantially does not use a solvent.

It can be applied to continuous polymerization, batch polymerization, or prepolymerization.

As the polymerization solvent in the case of slurry polymerization, saturated aliphatic or aromatic hydrocarbons such as hexane, heptane, cyclohexane, benzene, and toluene may be used alone or in mixtures.

The polymerization temperature is from room temperature to about 110°C, preferably 50 to 1
It is 00℃.

For example, hydrogen can be used as a molecular weight regulator.b The production of polyethylene by homopolymerization of ethylene is one typical embodiment of the process of the invention, but for this type of polymerization, copolymerization with ethylene can be used. The subject of the present invention is also a method for producing an ethylene copolymer containing up to about 10% by weight of α-olefins such as propylene, butene-11hexene-2, etc.

3. Experimental Examples Example 1 (1) Production of Component I) A stainless steel pot with an internal volume of 1 liter was filled with an apparent volume of 900 ml of stainless steel balls with a diameter of 12.7 mm, and titanium trichloride (TiCl3 (T
)) 18 g of anhydrous MgCA2170 g and 12 g of silicon tetrachloride were sealed under a nitrogen atmosphere and ground in a vibrating mill for 48 hours.

The amplitude was 5 mm and the motor rotation speed was 170 rpm.

After the pulverization was completed, the mixed pulverized solid composition was taken out from the pot in the dry box and weighed to obtain 180 g.

Next, purified heptane 607 and the above solid composition 12.9 were charged into a stainless steel catalyst preparation tank having an internal volume of 1OOl to prepare a titanium catalyst component slurry.

(2) Purified hebutane 70l 1 triisobutylaluminum 14 in a stainless steel autoclave with an internal volume of ethylene polymerization
g, the above solid composition sla IJ-51 (component I)
1), then heated to 70°C and added 3.0% ethylene while stirring. Feed 0 kg/hour.

The generated heat of polymerization was removed with cooling water, and the temperature inside the autoclave was maintained at 70°C.

3 hours after the start of ethylene supply, 2 g/h of the above solid composition slurry for 7 hours, 3.0 kg/h of ethylene, and 1013/h of heptane were introduced continuously for 7 hours, while the polymer slurry in the autoclave was constantly at 60 g/h of the above solid composition slurry. The polymer slurry is continuously discharged such that ˜701.

The H2 concentration in the gas phase is 55, which is a molecular weight regulator.
Control the capacity.

The pressure inside the autoclave is kept approximately constant at 8-10 kg/m2G.

The discharged polymer slurry is degassed, filtered, and dried to form a product powder.

After 120 hours, the supply of catalyst, heptane, ethylene, and hydrogen was stopped, and all the polymer slurry in the autoclave was discharged. When the inside of the autoclave was observed, it was found that the polymer had adhered to the inner wall of the tank, stirring blades, etc. was not recognized at all.

This means that 3000 g of polymer was obtained per 19 of the solid composition.

Average particle size 500μ, 5% below 100μ, 4% above 1000μ, bulk density 0. A polyethylene having good powder properties of 3897CC was obtained.

After making this polymer (powder) into pellets using an extruder,
190℃ by the method of STM-8 1238-65T
Melt-in desks (M■2 and M■10, respectively) with a load of 2.16 ky and 10.0 kg were measured.

Polyethylene having a wide molecular weight distribution with MI2=0.25 and FB (=MI1o/MI2)=15.6 indicating a wide molecular weight distribution and suitable for blow molding was obtained.

Example 2 A solid composition obtained by mixing and pulverizing under the same conditions as in Example 1 was used except that TiCls (H) was used as the Ti component of component 1), and the polymerization pressure was 9 to 11 kg/m2, Ethylene polymerization was otherwise carried out under the same conditions as in Example 1.

When the autoclave was observed in the same manner as in Example 1, no polymer was observed to adhere to the inner wall of the tank, stirring blades, etc.

MI=0.2 1, FB=16. l, bulk density 0.39g
/cc, was suitable for blow molding, and had good powder properties.

Example 3 TiCl3 (T) 60g, MgCl2 128g,
A solid composition obtained by mixing and pulverizing under the same conditions as in Example 1 was used for 0.997 hours, except that 12 g of SiCl4 was used, H2 concentration was 62%, and polymerization pressure was 8 to 9 kg/m2.
G, and ethylene polymerization was carried out under the same conditions as in Example 1 except for that.

When the autoclave was observed in the same manner as in Example 1, no polymer was observed to adhere to the inner wall of the tank, stirring blades, etc.

MI=0.32, PR=16.4, bulk density 0.37g/
cc, was suitable for blow molding, and had good powder properties.

Comparative example 1 TxCA3 (T) 1 3 7 g, MgCe25
1g, SiCA? A solid composition obtained by mixing and pulverizing under the same conditions as in Example 1 was used, except that 4 1 2 g was used, 1 g/hour was used, H2 concentration was 63%, and the polymerization pressure was 9.
12 kg/m2G, and other than that, ethylene was polymerized under the same conditions as in Example 1.

When the autoclave was observed in the same manner as in Example 1, about two groups of polymers were found to be attached to the inner wall of the tank, stirring blades, and other surfaces.

The polymer has MI=0.17, FR=16.8, bulk density 0
．． 33, a polyethylene having suitability for blow molding and good powder properties was obtained.

Example 4 A solid composition obtained by mixing and pulverizing under the same conditions as in Example I except for using CCl4 as the third component of component I) was used for 197 hours, and the polymerization pressure was 10 to 11 kg/m2.
G, and ethylene polymerization was carried out under the same conditions as in Example 1 except for that.

When the autoclave was observed in the same manner as in Example 1, no polymer was observed to adhere to the stirring blades or the like on the inner wall of the tank.

MI=O. l8, FB=15.8, bulk density 0. 3 8
，! 9/CC, was suitable for blow molding, and had good powder properties.

Comparative Example 2 Using 3 g/hour of a solid composition obtained by mixing and pulverizing under the same conditions as in Example 1 except that SiC4 was not added,
Ethylene polymerization was carried out under the same conditions as in Example 1 except that the polymerization pressure was 8 to 11 kg/m''G.

When the autoclave was observed in the same manner as in Example 1, polymer adhesion with a thickness of about 3 mm was observed all over the tank inner wall, stirring blade, etc.

A polyethylene with poor powder properties was obtained, with MI=0.33, FR=14.8, and bulk density 0.29, with an average powder particle size of 710 μ, 32% of which was 1000 μ or more, and 3% of which was 100 μ or less.

Example 5 A solid composition obtained under the same conditions as in Example 1 was used, except that TiCA3 (A) was used as the Ti component of component I) and triethylaluminum was used as the organic aluminum compound, H2 concentration was 50%, and the polymerization temperature was Ethylene polymerization was carried out under the same conditions as in Example 1 except at 85 DEG C. and a polymerization pressure of 7 to 9 kg/m'G.

When the autoclave was observed in the same manner as in Example 1, no polymer adhesion was observed.

MI = 5.3, FB = 9.0, bulk density 0.40g/
Average particle size of ccs powder 350μ, IO00μ or more1
% by weight, 7% by weight of 100μ or less, has suitability for injection molding, and has a bulk density of 0. Polyethylene having good powder properties of 40 g/cc was obtained.

Example 6 Copolymerization of ethylene and propylene was carried out under the same conditions as in Example 5 except that propylene was supplied at 2% by weight relative to ethylene, the H2 concentration was 45%, and the polymerization pressure was 8 to 10 kg/m G. .

No polymer adhesion was observed within the autoclave, and M
I-6.0, FB=8.8, bulk density 0. 3 7 g/
cc, suitable for injection molding, and having good powder properties was obtained.

Comparative Example 3 Solid composition 1 was mixed and pulverized under the same conditions as Comparative Example 2, except that oxygen gas was added during pulverization so that the 02/TiCl3 molar ratio was 0.6. Using 5 g/hour, H
2 concentration is 52%, polymerization pressure is 8 to 11 kg/m2G,
Ethylene polymerization was otherwise carried out under the same conditions as in Comparative Example 2.

When the autoclave was observed in the same manner as in Example 1, polymer adhesion about 0.5 mm thick was observed on the inner wall of the tank and on the entire surface of the stirring blade.

Catalytic activity 2000 g-PE/g one component I),
MI=0.30, FR=12.3, bulk density 0.28, average particle size of powder 630μ, 24% by weight of 1000μ or more
, iooμ or less by 5% by weight, polyethylene with poor powder properties was obtained.

Example 7 Ethylene polymerization was carried out under the same conditions as in Example 5 except that triethylaluminum was used l/h, the same solid composition as in Example 5 was used, and the polymerization pressure was 8 to 10 kg/mG. Ta.

When the autoclave was observed in the same manner as in Example I, no polymer adhesion was observed within the autoclave, and MI
=4.2, FB=9.3, bulk density 0. 3 8 9 /
cc, suitable for injection molding, and having good powder properties was obtained.

Claims (1)

[Scope of Claims] 1. A method for producing an ethylene polymer, which comprises polymerizing ethylene by bringing it into contact with a catalyst consisting of a combination of the following components 1) and 2). ■) A solid composition obtained by mixing and pulverizing the following components (1) to (3): (1) titanium trichloride, (2) a magnesium halide having a molar ratio of 3 or more to titanium trichloride, and (3) tetrachloride. Silicon chloride or carbon tetrachloride ■) Organoaluminium compounds.