JPH0424361B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for polymerizing olefins that causes less destruction of the polymer during polymerization and allows production of spherical polymers with a narrow particle size distribution. The present invention also relates to a method for polymerizing olefins that can produce highly stereoregular polymers when applied to the polymerization of α-olefins having 3 or more carbon atoms. In the present invention, the term "polymerization" is used to include not only homopolymerization but also copolymerization, and the term "polymer" is sometimes used to include not only homopolymers but also copolymers.

There are many proposals regarding highly active titanium catalyst components using a complex of a magnesium halide compound a and an organic hydroxy compound b as a carrier. For example, a method in which a titanium compound is directly reacted with the complex of (a) and (b), or a method in which the complex of (a) and (b) is reacted with an organoaluminum compound or a halogen compound such as silicon or tin in advance, and then a titanium compound is reacted with the complex. A method of reacting with an ester, etc. during each of the above reactions, or before or after each of the above reactions, a method of reacting an organoaluminum compound after reacting with a titanium compound in each of the above reactions, and various other methods are known. ing. When slurry polymerization or gas phase polymerization of olefin is performed using a catalyst formed from a titanium catalyst component and an organoaluminum compound catalyst component obtained by each of these methods, a small amount of finely powdered polymer is produced, and the polymerization May have adverse effects on handling and post-treatment of the polymer. The formation of such a finely divided polymer was sometimes observed even when a catalyst whose particle size had been adjusted in advance was used. On the other hand, an improvement method has been proposed in which a small amount of water is present during the formation stage of such a complex to prevent the formation of fine powder polymer (Japanese Patent Application Laid-open No. 18889/1989), and this method has achieved some results. According to the method specifically disclosed in this publication, the effect of highly reducing the generation of fine particles cannot be obtained. In particular, in polymerization processes involving gas phase polymerization, the production of a small amount of finely divided polymer has a large effect on operability, so further improvements have been desired. Furthermore, the use of such water sometimes causes a decrease in catalytic activity, and moreover, when applied to the stereoregular polymerization of α-olefins having 3 or more carbon atoms, the amount of amorphous polymer produced is ignored. In some cases, we saw an increase that could not be avoided.

The present inventors have discovered that the formation of such fine polymer particles occurs due to the destruction of polymer particles during the growth process of the polymer, and have attempted to prevent this as much as possible to produce polymers with excellent particle properties. As a result of our efforts, we found the following improvement method. Accordingly, an object of the present invention is to provide an improved method capable of producing a spherical olefin polymer having a small number of broken particles and a narrow particle size distribution with high catalytic activity. Another object of the present invention is to
The object of the present invention is to provide an improved method for polymerizing olefins, which allows the production of the stereoregular polymer of α-olefins in a high proportion. That is, the present invention
(A) Finely dispersed into a spherical complex with a narrow particle size distribution having an average particle size of about 5 to about 400μ and a geometric standard deviation of less than 2.1, obtained by granulating a liquid mixture of magnesium halogen compound a and organic hydroxy compound b (B) the presence of a catalyst formed from a titanium catalyst component prepared by using a carrier with a H ₂ O/Mg molar ratio of about 0.05 to about 1, and (B) an organoaluminum compound catalyst component; The present invention relates below to a method for polymerizing olefin, which is characterized by carrying out polymerization or copolymerization of olefin.

The carrier for preparing the titanium catalyst component A used in the present invention is a spherical carrier with a narrow particle size distribution and an average particle size of about 5 to about 400 μ, which is obtained by granulating a liquid mixture of a magnesium halide compound a and an organic hydroxy compound b. Obtained by treating the complex with finely dispersed water.

Specific examples of the magnesium halogen compound a include magnesium halides such as magnesium chloride, magnesium bromide, magnesium iodide, and magnesium fluoride; alkoxy (or Examples include (aryloxy)magnesium halide. Among these, those using magnesium halide, particularly magnesium chloride, are preferred.

Organic hydroxy compound b is alcohol or phenol. More specifically, methanol, ethanol, n-propanol, iso-propanol, n-butanol, sec-butanol,
Alcohols such as tert-butanol, n-hexanol, n-octanol, 2-ethylhexanol, n-decanol, oleyl alcohol, cyclopentanol, cyclohexanol, benzine alcohol, phenol, cresol, xylenol, ethylphenol, tert-butylphenol For example, phenols such as Among these, it is particularly preferable to use aliphatic alcohols having 2 to 7 carbon atoms.

The liquid mixture of a and b (presumed to form a complex) may be in a liquid state by melting or dissolving and may form a homogeneous solution, or may be dissolved in another solvent. It may also be a material that presents a heterogeneous solution. The mixing ratio of a and b in such a liquid mixture is approximately 2 moles of (b) to 1 mole of (a).
Preferably it is from about 8 mol, especially from about 2 to about 6 mol, more preferably from about 2 to about 4 mol. From the viewpoint of catalytic performance, it is preferable not to mix water into the mixture as much as possible. For example, (a)
The coexistence amount of water should be 0.08 mol or less per 1 mol, especially
It is preferably 0.06 mol or less.

Various methods can be employed to granulate such a liquid mixture into spherical particles. For example, a molten liquid mixture is suspended in an organic liquid medium containing a surfactant and then rapidly solidified.
According to the methods disclosed in JP-A No. 135102 and JP-A-55-135103, it is possible to produce a spherical solid complex having a desired average particle size and a narrow particle size distribution. Alternatively, as shown in JP-A-56-67311, it can also be produced by passing it through a thin pipe at high speed and then rapidly cooling it.

The solid complex obtained by these methods may be further classified to obtain a desired average particle size and particle size distribution. The average particle size of the solid complex is in the range of about 5 to about 400μ, preferably about 10 to about 200μ, and by preparing the titanium catalyst component from particles with such a particle size, slurry polymerization and gas phase polymerization can be carried out. A polymer having a particle size suitable for operation can be obtained. Further, for the same reason, it is preferable that the particle size distribution is narrow, and for example, it is preferable that the geometric standard deviation σg of the particle size distribution is less than 2.1, particularly 1.95 or less. Furthermore, since the fixed complex is spherical,
Not only is the operability in polymerization and post-treatment good, but particle destruction during polymerization can be more significantly suppressed. Here, the term spherical refers to not only a true sphere but also an elliptical sphere or a similar shape, in which the ratio of the major axis to the minor axis of the projected image of the particle is 3 or less.

A carrier is prepared by allowing a small amount of finely dispersed water to act on the spherical complex obtained as in the previous step. At this time, the spherical complex obtained by the above method may be used as a raw material as it is, or it may be used after partially removing component b by chemical or physical means. Finely dispersed water here refers to water that is dispersed as very small particles (for example, particle size of about 1.0μ or less) in a liquid medium, or water that is dispersed in a gaseous medium at a rate of about 20 mol% or less. refers to the moisture contained in One way to use water in this state is to add a small amount of water (e.g. 0.2
to about 6 g/m) and stir vigorously in the presence or absence of a small amount of surfactant to form a fine dispersion of water, and then mix this with a suspension of the spherical complex in an inert solvent. This is a method of mixing. Another method is to blow a water-containing gas into a suspension of the spherical complex in an inert solvent. The water treatment is carried out such that the water content in the treated material is in a H ₂ O/Mg molar ratio of about 0.05 to about 1, particularly about 0.1 to about 0.6. If the water content is higher than the above range, the decrease in catalyst activity cannot be ignored, or when used for the stereoregular polymerization of α-olefins having 3 or more carbon atoms, the stereoregularity index will decrease to a considerable extent, which is undesirable. Furthermore, when water is applied, it is not preferable to apply the reaction while the water particles are large, as this may cause destruction or agglomeration of the particles. Furthermore, the method in which water is applied later causes less destruction of the polymer and has better catalytic performance than the method in which water is applied in the early stage of forming the complex.

Various methods can be employed to produce the titanium catalyst component from the carrier thus obtained.

For example, Special Publication No. 46-34092, Special Patent Application No. 96490 (1973)
A method of directly reacting a titanium compound with the carrier as described in Japanese Patent Publication No. 50-32270, Japanese Patent Publication No. 53-21092
JP-A-49-72383, a method in which the support is reacted with an organometallic compound of a metal from Group 1 to Group 3 of the periodic table and then reacted with a titanium compound;
As in JP-A No. 49-88983, a method in which the carrier is reacted with a silicon or tin halide or an organic compound and a titanium compound sequentially or simultaneously; as in JP-A-51-28189, the support is A method of reacting an organic acid ester with an organic metal compound of Group 1 to Group 3 metal of the periodic table and then reacting with a titanium compound; and a method of reacting a titanium compound after reacting a halogen compound or an organic compound of silicon or tin; JP-A-Sho
As shown in No. 51-127185, a method in which the titanium compound catalyst component obtained by each of the above methods is further reacted with an organometallic compound of a metal in Groups 1 to 3 of the periodic table; JP-A-52-307888 A method of reacting an electron donor and a titanium compound with the titanium compound component obtained by each of the above methods;
etc. can be adopted. The support reaction is carried out by pre-treating the carrier as exemplified above or without pre-treating, suspending the carrier in a titanium compound forming a liquid phase under the carrier reaction conditions, or pre-treating the carrier as exemplified above. This can be carried out afterwards or without pretreatment by suspending the titanium compound in an inert solvent. The loading reaction may be carried out, for example, at about 0°C to about 200°C, preferably at about 200°C.
It can be carried out at 30 to about 150°C. The support reaction is also preferably carried out in the presence of an excess of titanium compound, for example per gram atom of Mg in the support.
Suitably, the titanium compound is present in an amount of about 0.1 to about 100 moles, more preferably about 1 to about 50 moles. The loading reaction can be carried out in two or more stages. The titanium compound used in the support reaction is preferably one that is liquid under the support reaction conditions or, if a solvent is used in the support reaction, soluble in the solvent. Specifically, the formula Ti
Examples include titanium compounds represented by (OR) _o X _4-o (wherein R is a hydrocarbon group, X is a halogen, and 0≦n≦4). Examples of the above R include a _C5 to _C8 cycloalkyl group, a _C2 to _C18 alkyl group, and a _C6 to _C15 aryl group. Furthermore, examples of x include chlorine, bromine, and iodine. Preferred is titanium tetrahalide, and titanium tetrachloride is particularly preferred.

Details of the method of pre-treating the carrier with an electron donor, an organometallic compound of Groups 1 to 3 of the periodic table, a halogen compound of silicon or tin, or an organic compound prior to supporting the titanium compound can be found in the example given above. As stated in each publication, for example,
The treatment can be carried out at a temperature of about 0°C to about 150°C while suspending the carrier in an inert solvent.

The preferred titanium catalyst component is titanium catalyst component.
It contains from about 3 to about 120 mg of titanium per gram, preferably from about 5 to about 60 mg. Also, halogen/
The titanium (atomic ratio) is preferably 6 or more, more preferably in the range of about 10 to about 50. The above catalyst component contains magnesium, halogen, and titanium as essential components, and may also contain an electron donor such as an organic acid ester depending on the case.

In the present invention, olefin is polymerized or copolymerized in the presence of a catalyst formed from the titanium catalyst component A and the organoaluminum compound catalyst component B obtained as described above.

Component B has a hydrocarbon group directly bonded to aluminum, and examples thereof include alkyl aluminum compounds, alkali metal alkyl aluminum compounds, alkyl aluminum hydrides, alkyl aluminum halides, and alkyl aluminum alkoxides. Among these, preferred compounds are:
A(C ₂ H ₅ ) ₃ , A(CH ₃ ) ₃ , A(C ₃ H ₇ ) ₃ ,
Trialkyl or trialkel aluminum such as A(C ₄ H ₉ ) ₃ , A(C ₁₂ H ₂₅ ) ₃ , (C ₂ H ₅ ) ₂
AOA (C ₂ H ₅ ) ₂ , (C ₄ H ₉ ) ₂ AOA (C ₄ H ₉ )
₂ , (C ₂ H ₅ ) ₂ AN (C ₆ H ₅ ) A (C ₂ H ₅ ) _2, an alkyl aluminum compound having a structure in which many A atoms are linked via oxygen or nitrogen atoms, (C ₂
Dialkyl aluminum hydrides such as H ₅ ) ₂ AH, (C ₄ H ₉ ) ₂ AH, (C ₂ H ₅ ) ₂ AC, (C
Dialkyl aluminum halides such as 2H ₅ ) ₂ AI, (C ₄ H ₉ ) ₂ AC, (C ₂ H ₅ ) ₂ A (OC ₂
H ₅ ), (C ₂ H ₅ ) ₂ A(OC ₆ H ₅ ), dialkyl aluminum alkoxides or phenoxides, or mixtures thereof, most preferably trialkylaluminum or mixtures thereof with alkyl aluminum halides. It is.

Examples of olefins used in polymerization include ethylene, propylene, 1-butene, 4-methyl-1-
Mention may be made of _C2 to _C10 olefins such as pentene, 1-octene, and the like. These polymers can be subjected to not only homopolymerization but also random copolymerization and block copolymerization. In copolymerization, polyunsaturated compounds such as conjugated dienes and non-conjugated dienes can be selected as copolymerization components. For example, when copolymerizing propylene, the propylene is polymerized to an amount of homopolymer equal to about 60 to about 90% by weight of the total composition, followed by a process of polymerizing a propylene-ethylene mixture or ethylene. You can take it. Alternatively, mixtures of propylene and ethylene can be polymerized to obtain copolymers containing up to about 10 mole percent ethylene.

Polymerization can be carried out in either liquid phase or gas phase. When carrying out liquid phase polymerization, an inert solvent such as hexane, heptane or kerosene may be used as the reaction medium, but olefin itself may also be used as the reaction medium. When performing liquid phase polymerization, the titanium catalyst component is about 0.0001 to about 1 mmol in terms of titanium atoms per liquid phase, and the amount of A atom in the organoaluminum compound catalyst component is about 1 to about 1 mmol per mole of titanium. Preferably, the amount is about 1000 moles, preferably about 5 to about 500 moles. In addition, when performing gas phase polymerization, a method using a fluidized bed or an agitated fluidized bed can be adopted, and the titanium catalyst component can be diluted with solids such as polyethylene, polypropylene, glass beads, silica, or hexane, olefin, etc. By doing so, the organoaluminum compound catalyst component is diluted with hexane, olefin, etc., or added to the polymerization vessel as it is without dilution, and in some cases, hydrogen or the like is further supplied in gaseous form into the polymerization vessel. Polymerization can be carried out by The proportions of catalysts, etc. used are the same as in the case of liquid phase polymerization.

The polymerization temperature of the olefin is generally from about 20 to about 200°C, preferably from about 20°C to a temperature below the melting point of the polyolefin to be produced, particularly preferably from about 40 to about 120°C. The polymerization can be carried out at atmospheric pressure to about 100 kg/cm ² G, preferably under pressurized conditions, particularly about 2 to about 50 kg/cm ² G.

When polymerizing olefins, the molecular weight can be controlled to some extent by changing polymerization conditions such as polymerization temperature and catalyst molar ratio, but it is effective to add hydrogen into the polymerization system. Furthermore, in the polymerization of α-olefins having 3 or more carbon atoms, alcohols, ethers, esters, amines, acid anhydrides, ketones, carboxylic acid amides, phosphorus compounds, polysiloxanes, alkoxysilane compounds, etc. An electron donor may also be present. They can also be used in the form of organoaluminum compound catalyst components or addition compounds with Lewis acids, such as AX ₃ .

According to the present invention, there is less crushing of the polymer during polymerization, and therefore, a spherical olefin polymer with a narrow particle size distribution and high bulk specific gravity can be obtained with less generation of fine polymer particles. The advantage is that post-processing is greatly simplified or, in many cases, not required at all. Therefore, even in gas phase polymerization that does not use any solvent, there are problems in the polymerization process, such as uniformity of the fluid state, process constraints due to the formation of finely divided polymer, and transportation of polymer powder within the process. A big improvement was made,
It is possible to obtain a polymer that can be used as a product as it is by solventless polymerization.

Example 1 In a container with an internal volume of 30 liters, 1 kg of anhydrous magnesium chloride, 1.4 kg of ethanol, 15.5 kg of decane,
39 g of sorbitan distearate was charged under a nitrogen atmosphere, and the temperature was raised to 130° C. with thorough stirring.
Stirring was continued for an additional 3 hours while adjusting the pressure to 6 kg/cm ² gauge with nitrogen gas. A well-insulated discharge line for discharging the internal solution from the bottom discharge port,
An emulsifying pipe with an inner diameter of 1 mm and a length of 1 meter was protruded from its tip. This liquid material was introduced into the gas phase of a 200 liter stirring vessel equipped with a cooling jacket, into which 50 liters of normal decane had been previously charged, and rapidly cooled to 25°C. After approximately 1 hour of operation, the supply to the cooling vessel was stopped and cooling continued for an additional 30 minutes.

The cooled liquid became a decane slurry containing spherical solid supports ranging in size from 5 to 400 microns.

This slurry was classified using a stainless steel wire mesh with an opening of 105 microns under a nitrogen atmosphere while being washed with decane. The slurry under the sieve from which coarse particles had been cut was classified again using a 53 micron wire mesh to obtain a 500 gk true spherical carrier as the solid content on the mesh. The molar ratio of ethanol to magnesium chloride in the carrier was 3.0, and the molar ratio of water to magnesium chloride was 0.026.
Further, the average particle size of the carrier was 75 μm, and the geometric standard deviation of the particle size was 1.29.

The particle size distribution was measured using a centrifugal sedimentation type particle size distribution measuring device "SA-CP2" manufactured by Shimadzu Corporation.
The weight fraction for each particle size was determined using decane as the solvent. Furthermore, the cumulative grain size of the unloaded grains was plotted on logarithmic probability paper, and the geometric standard deviation was determined from the obtained straight line according to the following formula.

Geometric standard deviation (σg) = particle size at cumulative fraction 15.87%/
Average particle size (= average particle size/particle size at cumulative fraction 84.13%) Separately, a mixture of 0.46 g of water, 500 c.c. of decane, and 0.1 g of sorbitan tristearate was prepared in a nitrogen atmosphere. Stir vigorously for 15 minutes to obtain a clear liquid. This was added to the decane suspension of 1 containing 50 g of carrier under stirring, and after stirring for 10 minutes, it was filtered and dried to obtain a powdery spherical carrier. The molar ratio of water to magnesium chloride in the carrier was 0.144.

Next, put 500 c.c. of titanium tetrachloride into the glass flask No. 1, add 25 g of the above spherical carrier while stirring, then add 16 mmol of diisobutyl phthalate, stir for 30 minutes, raise the temperature to 120°C, and add 25 g of the above spherical carrier. Stirred for an additional hour. After standing to separate, the supernatant was discarded, and 500 c.c. of fresh titanium tetrachloride at 130°C was added, stirred for 2 hours, and the solid portion was collected by filtration, thoroughly washed with hexane, and then dried.

2 autoclave was charged with 0.75% hexane, and triethylaluminum was added under a propylene atmosphere.
3.75mmol, diphenylmethoxysilane 0.5mmol
and the above Ti-containing solid catalyst in terms of Ti atoms.
0.0225 mg-atom charge.

After adding 400Nm of hydrogen, the system was heated to 60℃,
The total pressure was increased to 7.0 Kg/cm ² G using propylene, and polymerization was carried out for 4 hours while maintaining the propylene pressure. After the polymerization was completed, the slurry containing the polymer was filtered to obtain 653 g of a hard, spherical white powder polymer, with a boiling n-heptane extraction residue of 97.4% and an apparent specific gravity of
It was 0.41g/ml. Also, the average particle size of the polymer is
1400μ, logarithmic standard deviation 0.50, and the weight percentage of fine powder of 420μ or less was 4.8%. Also,
The spherical polymer particles produced were hard and there were very few crushed particles.

Comparative Example 1 In Example 1, the same treatment with titanium tetrachloride was carried out without adding water to the carrier after classification, and propylene polymerization was carried out in the same manner. The amount of polymerized polymer was 698 g, and the apparent specific gravity was 0.38, n-
Although the heptane extraction residual rate was 97.2%, which was close to that of Example 1, the produced polymer particles were soft and could be easily broken with fingers. In addition, many particles are crushed, and the weight percentage of particles smaller than 420μ is 7.8
increased to %.

Example 2 Using the same procedure as used in Example 1, the amount of water added to the spherical carrier was determined by the molar ratio of water and magnesium chloride.
Polypropylene was obtained in exactly the same manner except that the value was 0.47. The amount of polymerization was 630g, the residual rate of n-heptane extraction was 97.3%, the polymer particles were hard and had few cracks, the apparent specific gravity was 0.41, and the proportion of particles below 420μ was
It was 3.9%.

Comparative Example 2 Water was added in advance to the ethanol added to magnesium chloride in Example 1, and emulsion granulation was performed to obtain a spherical carrier. This spherical support had the same average particle size and geometric standard deviation as that of Example 1. The molar ratio of water and magnesium chloride in the carrier is
It was 0.305. The unclassified titanium tetrachloride treatment and propylene polymerization treatment were carried out in the same manner as in Example 1 to obtain polypropylene particles. The obtained polypropylene had decreased to 450 g, the n-heptane extraction residue was low at 93.8%, the apparent specific gravity was 0.31, and the particles were soft, with some wind-shaped particles and flat particles being observed. However, the proportion of 420μ or less was also high at 6%.

Comparative Example 3 A similar method was used in Example 1 to prepare a decane slurry containing spherical solid supports in the particle size range of 5-400 microns as the cooled liquid. This slurry was classified using a 105 micron stainless steel wire mesh in a nitrogen atmosphere while being washed with decane to obtain coarse particles as a wire mesh. Furthermore, the slurry that passed through the 105 micron wire mesh was classified into upper and lower mesh components using a 53 micron wire mesh, and the entire slurry was divided into three particle sizes. For intermediate particle size components of 53 microns or more and 105 microns or less, take about one-third of the slurry and refill with a 105 micron mesh particle.
53 Cumilon mixed with netheria. When the particle size distribution of this slurry was measured, the average particle size was 78 microns.
The geometric standard deviation was 2.53. This slurry was sedimented and concentrated to prepare a 1 liter suspension in decane containing 50 g of carrier. For this suspension, Example 1
Water dispersed in decane was brought into contact with it in the same manner as above. The subsequent operations were the same as in Example 1 to adjust the titanium catalyst component. Using the catalyst component, propylene polymerization was carried out in the same manner as in Example 1 to obtain 420 g of polymer particles.

The spherical polymer particles produced were a mixture of hard particles, many crushed pieces, and soft particles, and had an apparent specific gravity of 0.32. Further, the n-heptane extraction residual rate was as low as 93.9%.

[Brief explanation of drawings]

FIG. 1 is a flowchart schematically showing the preparation of an olefin polymerization catalyst and its use in olefin polymerization according to the method of the present invention.

Claims (1)

[Claims] 1 (A) Magnesium halide a and alcohol b
H ₂ O/ Ti(OR) _o X _4-o (wherein, R is a hydrocarbon group, X is a halogen, 0≦n< The method is characterized in that olefin polymerization or copolymerization is carried out in the presence of a catalyst formed from a titanium catalyst component prepared by supporting a halogen-containing titanium compound represented by 4) and (B) an organoaluminum compound catalyst component. A method for polymerizing olefin.