JPS6346084B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a process for the gas phase polymerization of ethylene using highly active Ziegler type catalysts. More specifically, the present invention involves contacting a catalyst made of a solid substance containing Mg, Ti and/or V, and an organometallic compound with an α-olefin in the presence of a liquid hydrocarbon, and then treating the catalyst with ethylene or ethylene. The present invention relates to a method for producing polyolefin, which comprises homopolymerizing ethylene or copolymerizing ethylene and α-olefin by contacting the mixture with α-olefin in a gaseous state.

Conventionally, MgO, Mg(OH) ₂ , MgCl ₂ , MgCO ₃ ,
It is known that a catalyst system in which a transition metal is supported on various Mg-containing solid supports such as Mg(OH)Cl and then combined with an organometallic compound can be a highly active catalyst for olefin polymerization. It is also known that reactants of various organomagnesium compounds such as RMgX, R ₂ Mg, and RMg (OR) with transition metal compounds can serve as excellent catalysts for the high polymerization of olefins (Japanese Patent Publication No. 39-12105, Belgian Patent No. 742112, Special Publication No. 13050, Special Publication No. 45-9548, and others).

Polymerization of olefins using highly active Ziegler-type catalysts is usually carried out in a liquid phase using an inert hydrocarbon such as butane, pentane, hexane, or heptane as a solvent, but separation, recovery, purification, and The reuse process is complicated, and in order to greatly simplify the process, attempts have also been made to use a gas phase polymerization method in which the olefin is polymerized in substantially no liquid phase, that is, in a gas phase.
In this method, a catalyst is supplied into a bed consisting of polymer particles introduced in advance or granular polymer particles produced as the polymerization progresses, and contacts the gaseous raw material olefin to produce a polymer.

In such a gas phase polymerization method, if a so-called highly active catalyst is used, there is no need to recover the polymerization solvent, and the steps of separating and deactivating the catalyst can be omitted, so the process as a whole can be extremely simple. Due to such technical problems, it is still difficult to implement such a gas phase polymerization method industrially advantageously.

As described above, the gas phase polymerization method has the potential to be an extremely simplified process, but many technical problems must be solved in order to implement it industrially advantageously. For example, first of all, it is necessary to use a catalyst that is highly active to the extent that a catalyst residue removal process is not required, and that the generated polymer particles do not adhere to the reactor wall, stirrer, etc. Abnormal phenomena such as coarsening or agglomeration of coalesced particles that may cause blockage of the polymer outlet from the reactor, transportation lines, etc. should not occur, and the proportion of ultrafine particles that are easily scattered during polymerization should be small. , good particle properties such as bulk density are important technical issues.

The present inventors have completed the present invention as a result of intensive research into the above-mentioned technical problems.The method of the present invention allows extremely stable gas phase polymerization reactions and also eliminates the catalyst removal step. An extremely simple gas phase polymerization method for ethylene has been completed.

That is, the present invention provides a catalyst comprising an inorganic magnesium compound, a halogen, a solid substance containing Ti or Ti and V, and an organometallic compound selected from organoaluminum compounds and organozinc compounds in the presence of a liquid hydrocarbon. After contact treatment with 1 g to 500 g of α-olefin per 1 g of the solid substance, ethylene or a mixture of ethylene and α-olefin is contacted in a gas phase to homopolymerize ethylene or copolymerize ethylene and α-olefin. The present invention relates to a method for producing a polyolefin characterized by polymerizing an inorganic magnesium compound, a halogen, a solid substance containing Ti or Ti and V, an organoaluminum compound, and an organozinc compound. By bringing a catalyst made of an organometallic compound into contact with an α-olefin in the presence of a liquid hydrocarbon and then performing gas phase polymerization of ethylene, compared to a case where the catalyst is not brought into contact with an α-olefin, The activity is extremely high, the proportion of coarse particles and ultrafine particles is reduced, the particle properties are good, and there is very little adhesion to the reactor or agglomeration of polymer particles, allowing for very stable gas phase polymerization. It became clear that the reaction could be carried out. It must be said that it is a completely unexpected and surprising fact that the method of the present invention has made it possible to carry out gas phase polymerization reactions extremely smoothly even in systems for which stable operation has hitherto been difficult.

The inventors of the present invention previously found that by bringing a catalyst into contact with a gaseous α-olefin and then performing a gas phase polymerization reaction, the activity was increased and the particle properties of the polymer were improved, and they applied for a patent. The invention is a further improvement of the prior invention, and the present invention makes it possible to introduce the α-olefin treated product of the catalyst into the polymerization reaction tank in a slurry state, making the operation easier. Another advantage of the present invention is that the heat of polymerization reaction can be easily removed due to the latent heat of vaporization when introduced into the polymerization reaction tank.

The catalyst system used in the present invention comprises an inorganic magnesium compound, a halogen, Ti or Ti and V
is a combination of a solid substance containing the above-mentioned organometallic compound, and the solid substance includes an inorganic solid support made of an inorganic magnesium compound such as magnesium hydroxide, magnesium carbonate, magnesium oxide, magnesium chloride, silicon, aluminum, etc. , double salts, double oxides, carbonates, chlorides, hydroxides, etc. containing a metal selected from calcium and a magnesium atom, and furthermore, these inorganic solid carriers can be combined with oxygen-containing compounds, sulfur-containing compounds, hydrocarbons, halogens, etc. Examples include those in which a titanium compound or a titanium compound and a vanadium compound are supported on an inorganic solid support, such as one treated or reacted with a containing substance, by a known method.

Examples of the titanium compound and vanadium compound here include halides, alkoxy halides, oxides, and halogenated oxides of titanium and vanadium. Specific examples of these include titanium tetrachloride, titanium tetrabromide, titanium tetraiodide,
Monoethoxytrichlorotitanium, diethoxydichlorotitanium, triethoxymonochlorotitanium, tetraethoxytitanium, monoisopropoxytrichlorotitanium, diisopropoxydichlorotitanium,
Examples include tetravalent titanium compounds such as tetraisopropoxytitanium, and various titanium trihalides obtained by reducing titanium tetrahalides with hydrogen, aluminum, titanium, or organometallic compounds.
Also, trivalent titanium compounds such as compounds obtained by reducing various tetravalent alkoxytitanium halides with organometallic compounds, tetravalent vanadium compounds such as vanadium tetrachloride, vanadium oxytrichloride, orthoalkylpanadate. Examples include pentavalent vanadium compounds such as, vanadium trichloride, and trivalent vanadium compounds such as vanadium triethoxide.

As the catalyst of the present invention, a combination of a solid material obtained by supporting a titanium compound or a titanium compound and a vanadium compound on the solid carrier described above and an organometallic compound is used.

Specific examples of these catalysts include, for example, MgO-RX-TiCl ₄ system (Japanese Patent Publication No. 51-3514),
Mg- _SiCl4 -ROH- _TiCl4 system
), MgCl ₂ −Al(OR) ₃ −TiCl ₄ system (Special Publication No. 51-
152, Special Publication No. 52-15111), MgCl ₂ −SiCl ₄ −
ROH-TiCl ₄ system (JP-A-49-106581), MgCl ₂
An example of a preferable catalyst system is one in which an organometallic compound is combined with a solid substance (in the above formula, R represents an organic residue) such as -AlOCl-TiCl ₄ system (Japanese Patent Application Laid-open No. 133386/1986). .

In the present invention, the catalyst system described above is brought into contact with an α-olefin in the presence of a liquid hydrocarbon, and then used for a gas phase polymerization reaction. Various α-olefins can be used at this time, but α-olefins having 3 to 12 carbon atoms are preferred, and α-olefins having 3 to 8 carbon atoms are more preferred. Examples of these α-olefins include propylene, 1-butene, 1-pentene, 1-heptene, 1-hexene, 1-octene, and mixtures thereof. In addition, the liquid hydrocarbon used at this time is a hydrocarbon that becomes liquid under contact treatment conditions, and examples of these include n-paraffin, iso-paraffin, and aromatic hydrocarbons having 3 to 12 carbon atoms. but preferably has 3 to 8 carbon atoms
Examples include n-paraffin, iso-paraffin, and aromatic hydrocarbons. Specific examples of these hydrocarbons include propane, n-butane,
iso-butane, n-pentane, iso-pentane, n
-hexane, n-heptane, n-octane, iso
-Octane, benzene, toluene, xylene, etc. may be mentioned.

Further, the α-olefins mentioned above can also be used as the liquid hydrocarbon of the present invention.

The amount of liquid hydrocarbon used in the present invention is
If the amount is too large, it will be difficult to carry out a stable gas phase reaction in the polymerization reaction tank, and if it is too small, it will be difficult to introduce the α-olefin contact product of the catalyst into the polymerization reaction tank.
A desirable range is g to 1000 g, preferably 5 g to 500 g, and more preferably 10 g to 300 g. The temperature and time during the contact between the catalyst of the present invention and α-olefin can be selected within a wide range, for example, from 0 to 200°C.
The contact treatment can be carried out at a temperature of 0°C to 110°C for 1 minute to 24 hours.

The amount of α-olefin contacted is from 1 to 500 g per gram of the solid material. At this time, the pressure at the time of contact can be arbitrarily selected, but usually -1 to
It is desirable that the contact be made under a pressure of 100 kg/cm ² ·G.

In the present invention, the entire amount of the organometallic compound used may be combined with the solid substance and then brought into contact with the α-olefin, or a part of the organometallic compound used may be combined with the solid substance and then brought into contact with the α-olefin. The polymerization reaction may be carried out by contacting with α-olefin and adding the remaining organometallic compound separately during the gas phase polymerization of ethylene. Further, when the catalyst and the α-olefin are brought into contact, there is no problem even if hydrogen gas coexists, and there is no problem even if other inert gases such as nitrogen, argon, helium, etc. coexist.

As described above, ethylene is polymerized using a catalyst that has been subjected to contact treatment with α-olefin, but in the present invention, copolymerization of ethylene and α-olefin other than ethylene can also be performed. In the polymerization reaction, ethylene or a mixture of ethylene and other α-olefins is polymerized in the gas phase. As the reactor used, known reactors such as a fluidized bed and a stirring tank can be used.

The polymerization reaction temperature is usually 20 to 110°C, preferably
The temperature is 50 to 100℃, the pressure is normal pressure to 70Kg/ ^cm2・G,
Preferably it is 2 to 60 kg/cm ² ·G. Although the molecular weight can be controlled by adjusting the polymerization temperature, the molar ratio of the catalyst, the amount of comonomer, etc., it is effectively carried out by adding hydrogen to the polymerization system. of course,
Using the method of the present invention, two-stage or more multi-stage polymerization reactions with different polymerization conditions such as hydrogen concentration, comonomer concentration, and polymerization temperature can be carried out without any problem.

The organometallic compounds used in the present invention are organoaluminum compounds and organozinc compounds that are well known as components of Ziegler's catalyst. Specific examples include the general formulas R ₃ Al, R ₂ AlX, RAlX ₂ , R ₂ AlOR,
Organoaluminum compounds of RAl( _OR )X and R ₃ Al ₂ general formula
R ₂ Zn (R is an alkyl group having 1 to 20 carbon atoms and may be the same or different) is an organic zinc compound such as triethylaluminum, triisobutylaluminum, trihexylaluminum, trihexylaluminum, Examples include octylaluminum, diethylaluminum chloride, ethylaluminum sesquichloride, diethylzinc, and mixtures thereof.

In the present invention, the amount of the organometallic compound used is not particularly limited, but is usually
It can be used in amounts of 0.1 to 1000 moles.

The method of the present invention is applicable to the homopolymerization of ethylene and the copolymerization of ethylene with an α-olefin other than ethylene, and the α-olefin in this case can be the α-olefin used in contact with the catalyst system. They may be the same or different. Examples of these α-olefins include propylene, butene-1, pentene-1, hexene-1, 4-methylpentene-1, octene-1, etc.
1, various α- such as decene-1 and dodecene-1
Examples include olefins and mixtures thereof. Copolymerization can also be carried out by further adding various dienes such as butadiene, 1,4-hexadiene, and ethylidenenorbornene as comonomers to ethylene or the mixture of ethylene and the above-mentioned α-olefins.

Examples will be described below, but these are for illustrative purposes in carrying out the present invention, and the present invention is not limited thereto.

Example 1 (1) Propylene pretreatment In a 200 ml stainless steel autoclave equipped with an induction stirrer, 10 g of anhydrous magnesium chloride, 0.5 g of dichloroethane, and 3.3 g of titanium trichloride/aluminum trichloride eutectic were ball milled at room temperature for 16 hours under a nitrogen atmosphere. 200 mg of the solid material obtained, 20 mmol of triisobutylaluminum and hexane
100 ml was introduced and reacted at 70°C for 10 minutes. Thereafter, 3 g of propylene was added and reacted for 10 minutes, and then cooled to room temperature to obtain a propylene pretreated catalyst slurry.

(2) Gas phase polymerization The autoclave equipped with a stainless steel induction stirrer in step 2 was purged with nitrogen, and the dried polyethylene powder 50
Next, 5 ml of the propylene pretreated catalyst slurry obtained in step (1) above was added and the temperature was raised to 80°C. Hydrogen was then charged until the total pressure reached 5 kg/cm ² ·G, and then ethylene was added at a total pressure of 10 kg/cm 2 .G. Polymerization was started by filling the solution until the temperature reached cm ² ·G. Ethylene was continuously introduced so that the total pressure was 10 Kg/cm ² ·G, and polymerization was carried out at 85°C for 2 hours, resulting in 193 g of white polyethylene.
I got it. By gas phase polymerization, subtracting the weight of the polyethylene powder initially fed into the autoclave,
The amount of newly produced polyethylene was 143 g. The catalytic activity was significantly higher than that of Comparative Example 1 described later in which the catalyst was not pretreated with propylene using 255,400 g polyethylene/g Ti, and there were no polymer aggregates or adhesion inside the autoclave. Very good results were obtained compared to the case using a catalyst without.

In addition, the polyethylene particles produced had a high bulk density and a low proportion of coarse particles and ultrafine particles, and the particle properties were very good.

Comparative Example 1 Polymerization was carried out in the same manner as in Example 1, except that the hexane slurry of the catalyst was not treated with propylene, and 45 g of white polyethylene was produced by gas phase polymerization. The activity is
80,400g polyethylene/gTi was smaller than that of Example 1, and 41g of polyethylene was attached to the flange surface of the autoclave and the upper part of the reactor wall, and the adhesion was significant.

Example 2 Pretreatment was carried out in the same manner as in Example 1, except that in the propylene pretreatment step of Example 1, 1 g of propylene was used instead of 3 g of propylene.
and gas phase polymerization, white polyethylene 131
g was obtained by gas phase polymerization. The activity was 234,000 g polyethylene/g Ti, which was significantly higher than that of Comparative Example 1, and no adhesion was observed inside the autoclave.

Example 3 Example 1 except that butene-1 pretreatment was performed instead of propylene pretreatment in Example 1, and that 2 g of butene-1 was added.
The same α-olefin pretreatment and gas phase polymerization reaction were performed to obtain 125 g of white polyethylene by gas phase polymerization. Activity is 223,200g polyethylene/g
The Ti content was significantly higher than that of Comparative Example 1, and no adhesion was observed in the autoclave.

Example 4 Propylene pretreatment and gas phase polymerization reaction were carried out in the same manner as in Example 1 except that 100 ml of n-butane was used instead of 100 ml of hexane in the propylene pretreatment step of Example 1. 151 g of polyethylene was obtained by gas phase polymerization. The activity is
269600g polyethylene/gTi and comparative example 2 below
In addition, no adhesion was observed inside the autoclave and the particle properties were good.

Comparative example 2 In place of 100ml of hexane in Example 1, n
Polymerization was carried out in the same manner as in Example 1, except that 100 ml of -butane was used and no propylene pretreatment was performed, and 50 g of white polyethylene was obtained by gas phase polymerization. The activity was 89,300 g polyethylene/g Ti, which was lower than that of Example 4, and a large amount of polyethylene was attached to the flange surface of the autoclave and the upper part of the reactor wall, and the polymer particles were also irregular.

Example 5 (1) Hexene-1 pretreatment Hexene-1 was obtained by ball milling 10 g of anhydrous magnesium chloride, 0.5 g of dichloroethane, and 1.7 g of titanium tetrachloride at room temperature for 16 hours in a 200 ml stainless steel autoclave with an induction stirrer under a nitrogen atmosphere. 200 mg of solid material, 20 mmol of triisobutylaluminum and 100 ml of hexane were introduced and reacted for 10 minutes at 80°C. Afterwards, add 5g of hexene-1 and
react for an hour, then cooled to room temperature and hexene-1
A pretreated catalyst slurry was obtained.

(2) Gas phase polymerization The autoclave equipped with a stainless steel induction stirrer in step 2 was purged with nitrogen, and the dried polyethylene powder 50
g, and then hexene-1 obtained in (1) above.
After 5 ml of pretreated catalyst slurry was added and the temperature was raised to 85°C, hydrogen was charged to a pressure of 5 kg/cm ² G, and then ethylene was charged to a total pressure of 10 kg/cm ² G to start polymerization. . Ethylene was continuously introduced so that the total pressure was 10 kg/cm ² ·G, and polymerization was carried out at 85° C. for 2 hours, whereby 62 g of white polyethylene was obtained by gas phase polymerization. The catalyst activity was significantly higher than that of Comparative Example 3 described later in which the catalyst was not treated with hexene-1 at 155,000 g polyethylene/g Ti, and there were no polymer aggregates or adhesion inside the autoclave. 1. Very good results were obtained compared to the case using a catalyst without pretreatment.

In addition, the polyethylene particles produced had a high bulk density and a low proportion of coarse particles and ultrafine particles, and the particle properties were very good.

Comparative Example 3 In Example 5, gas phase polymerization was carried out in the same manner as in Example 5, except that the catalyst was not treated with hexene-1, and 37 g of white polyethylene was obtained by gas phase polymerization. The catalytic activity was 92,500 g polyethylene/g Ti, which was lower than that in Example 5, and a large amount of polyethylene was attached to the autoclave flange surface and the upper part of the inner wall, and the polymer particles were also irregular.

Example 6 In Example 1, 40 g of magnesium oxide and 133 g of aluminum chloride were mixed as solid substances at 300°C.
Propylene was prepared in the same manner as in Example 1, except that 9.5 g of the reactant obtained by heating reaction for 1 hour and 1.7 g of titanium tetrachloride were ball-milled at room temperature for 16 hours under a nitrogen atmosphere. Gas phase polymerization was carried out in the same manner as in Example 1, except that ethylene containing 2 mol% butene-1 was used in the next gas phase polymerization reaction, and 93 g of white polyethylene was obtained. I got it newly. Catalytic activity is 238500g polyethylene/g
The Ti content was significantly high, and no adhesion was observed inside the autoclave.

Example 7 Magnesium oxide 400g and aluminum chloride 1.3
Reactant obtained by reacting with Kg at 300℃ for 4 hours
950g, titanium tetrachloride 180g and VO
(OC ₂ H ₅ ) ₃ was ball milled for 14 hours at room temperature under a nitrogen atmosphere to support the titanium compound and vanadium compound on the carrier. This solid material contained 39 mg titanium and 9.7 mg vanadium per gram.

Introducing 200 mg of the above solid substance, 20 mmol of triisobutylaluminum and 100 ml of hexane,
The reaction was carried out at 70°C for 10 minutes. Then, 4g of propylene was added and reacted for 10 minutes, then cooled to room temperature.
A propylene pretreated catalyst slurry was obtained.

The autoclave equipped with a stainless steel induction stirrer in step 2 was purged with nitrogen, and the dried polyethylene powder 50
Next, 5 ml of the propylene pretreated catalyst slurry obtained above was added and the temperature was raised to 80°C. Hydrogen was then charged to a pressure of 5 kg/cm ² .G, and then ethylene was added to a total pressure of 10 kg/cm ² . The mixture was tensioned until the temperature reached G and polymerization was started. Ethylene was continuously introduced so that the total pressure was 10 kg/cm ² ·G, and polymerization was carried out at 85° C. for 2 hours to obtain 185 g of white polyethylene. Subtracting the weight of the polyethylene powder initially supplied to the autoclave, the amount of polyethylene newly produced by gas phase polymerization was 135 g.
The catalyst activity was 241,000 g polyethylene/g Ti.

In addition, the polyethylene particles produced had a high bulk density and a low proportion of coarse particles and ultrafine particles, and the particle properties were very good.

[Brief explanation of the drawing]

FIG. 1 is a flowchart showing the steps for preparing a catalyst used in the method of the present invention.

Claims (1)

[Claims] 1 Inorganic magnesium compound, halogen,
A catalyst consisting of a solid substance containing Ti or Ti and V and an organometallic compound selected from an organoaluminum compound and an organozinc compound is heated in the presence of a liquid hydrocarbon in an amount of 1 g to 500 g of α-olefin per 1 g of the solid material. A method for producing polyolefin, which comprises contacting with ethylene or a mixture of ethylene and α-olefin in a gas phase to homopolymerize ethylene or copolymerize ethylene and α-olefin. .