JP3300999B2 - Olefin polymerization catalyst component, catalyst and method for producing polyolefin using the same - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a novel solid catalyst component, a catalyst and a method for producing a polyolefin using the same. More specifically, the present invention significantly increases the polymer yield per solid and polymer yield per transition metal,
As a result, the step of removing the catalyst residue in the polymer is made unnecessary, and at the same time, the bulk density of the produced polymer is high, the average particle diameter is large, and the fine particle portion is small. The present invention relates to a catalyst component for producing a polyolefin having a narrow molecular weight distribution and a narrow composition distribution in a copolymer, and its use.

[0002]

BACKGROUND OF THE INVENTION In the production of polyolefins, especially ethylene polymers or ethylene / α-olefin copolymers, a catalyst comprising a zirconium compound (typically a metallocene compound) and an alumoxane is used. The use is described in JP-A-58-193.
No. 09 is known. This technique not only has the advantage of producing an ethylene-based copolymer in high yield, but also has the advantage that the copolymer has a narrow molecular weight distribution and a narrow composition distribution. However, the above-mentioned catalyst components are often soluble in the reaction system, and when used in slurry polymerization or gas phase polymerization, the resulting polymer has a problem that the bulk density is extremely small and the granular properties are inferior.

On the other hand, a method using a catalyst formed from an aluminoxane and a solid catalyst component in which the transition metal compound is supported on a porous inorganic oxide carrier such as silica or silica-alumina is also disclosed in JP-A-60-35006. JP 60
JP-A-350007 and JP-A-60-35008, and furthermore, JP-A-61-31404.
JP-A-61-108610 and JP-A-60-106808 also propose a method of using a solid catalyst component supported on a similar porous inorganic oxide carrier. In the methods described in these prior arts, the polymerization activity is greatly reduced by employing a supported solid catalyst component, and many fine powders and coarse particles are found in the obtained polymer, and the bulk density is also low. In many cases, powder properties such as low were insufficient.

The inventors of the present invention have conducted intensive studies to solve the above-mentioned drawbacks. As a result, by using a specific solid catalyst component, a polyolefin having a narrow molecular weight distribution, a narrow composition distribution and excellent granular properties can be obtained. It has been found that it can be produced in high yield.

[0005]

That is, the present invention relates to a method for preparing a compound having at least a cycloalkadienyl ring, which is a transition metal of Group IV of the Periodic Table having a valency of metal of four, and comprising a silicon oxide and / or An olefin polymerization solid catalyst component supported on aluminum oxide, wherein the silicon oxide and / or aluminum oxide satisfies the following characteristics (A) to (E): It relates to a catalyst component. (A) The average particle size measured by the sieving method is 20 to 150 μ
m. (B) The specific surface area measured by the BET method is 150 to 600
m ² / g. (C) Pore radius 18 to 1,000 measured by mercury intrusion method
0.3-2.0 cm pore volume during 0 Å
³ / g. (D) The apparent specific gravity measured according to JIS-K6220-6.8 is 0.35 or more . (E) After the particles classified into the range of 53 μm or more and 75 μm or less by the sieving method are subjected to ultrasonic destruction treatment at 40 KHz and 35 W for 20 minutes, the particle ratio of 50 μm or less (ultrasonic destruction) is 30% or less. .

Further, the present invention is a Group IV transition metal compound of the Periodic Table having at least a cycloalkadienyl ring
In a solid catalyst component for olefin polymerization in which a compound having a valency of metal of 4 is supported on a silicon oxide and / or an aluminum oxide, the silicon oxide and / or the aluminum oxide may have any of the above (A) to The present invention relates to an olefin polymerization catalyst comprising a modified organoaluminum compound containing an Al-O-Al bond obtained by reacting a solid catalyst component for olefin polymerization, an organoaluminum compound, and water, which satisfies the characteristic (E). .

Further, the present invention is a Group IV transition metal compound of the Periodic Table having at least a cycloalkadienyl ring
In a solid catalyst component for olefin polymerization in which a compound having a valency of metal of 4 is supported on a silicon oxide and / or an aluminum oxide, the silicon oxide and / or the aluminum oxide are represented by the following (A) to (a). Existence of a catalyst comprising a solid catalyst component for olefin polymerization characterized by satisfying the characteristics of (E) and a modified organoaluminum compound containing an Al-O-Al bond obtained by reacting an organoaluminum compound with water. The present invention relates to a method for producing a polyolefin, which comprises polymerizing or copolymerizing an olefin.

[0008] The solid catalyst component used in the present invention comprises:
Usually used together with the promoter component, the type is not particularly limited, usually by combining with a modified organoaluminum compound having an Al-O-Al bond,
Used as a catalyst for olefin polymerization. Hereinafter, the solid catalyst component for olefin polymerization, the catalyst, and the method for producing a polyolefin of the present invention will be specifically described.

The transition metal compound of Group IV of the periodic table having a cycloalkadienyl ring used in the present invention is generally a compound of the general formula (Cp) _m MeR _n X _4-mn (where Cp is a cycloalkalidienyl ring). Dienyl ring, Me represents a Group IV transition metal, R represents hydrogen or an alkyl group having 1 to 24 carbon atoms, an aryl group, an aralkyl group, an alkoxy group, X
Is a halogen atom, 0 <m ≦ 4, 0 ≦ n <4, 0 <m + n
≦ 4. ) Is desirable. The cycloalkadienyl ring referred to in the present invention usually has 5 carbon atoms.
~ 20, preferably 5 ~ 12, for example, cyclopentadienyl group, substituted cyclopentadienyl group, indenyl group, substituted indenyl group and the like,
Examples of the substituent include a hydrocarbon group having 1 to 6 carbon atoms (specifically, an alkyl group, an aralkyl group, and the like). There may be two or more substituents. Specific examples of such a cycloalkadienyl group include a cyclopentadienyl group, a methylcyclopentadienyl group, an ethylcyclopentadienyl group, a cimethylcyclopentadienyl group, an indenyl group, and a tetrahydroindenyl group. It is mentioned as a thing.

In the above general formula, Me represents a Group IV transition metal, usually Zr, Ti or Hf, and particularly preferably Zr. R is hydrogen or an alkyl group having 1 to 24, preferably 1 to 12, more preferably 1 to 8, alkyl, aryl, aralkyl, or alkoxy group;
Examples of the alkyl group include a methyl group, an ethyl group, a propyl group, an isopropyl group, and a butyl group.Examples of the aryl group include a phenyl group and a tolyl group. Is, for example, a benzyl group, a neophyl group or the like, and examples thereof include an alkoxy group, a methoxy group, an ethoxy group, a propoxy group, a butoxy group, and a 2-ethylhexyloxy group.

Examples of the halogen atom include fluorine, chlorine, bromine and the like. The following compounds can be exemplified as these specific compounds. Bis (cyclopentadienyl) zirconium monochloride monohydride, bis (cyclopentadienyl) zirconium monobromide monohydride, bis (cyclopentadienyl) methylzirconium hydride, bis (cyclopentadienyl) ethylzirconium hydride, bis ( Cyclopentadienyl) cyclohexyl zirconium hydride, bis (cyclopentadienyl) phenyl zirconium hydride, bis (cyclopentadienyl) benzyl zirconium hydride,
Bis (cyclopentadienyl) neopentyl zirconium hydride, bis (methylcyclopentadienyl)
Zirconium monochloride monohydride, bis (indenyl) zirconium monochloride monohydride, bis (cyclopentadienyl) zirconium dichloride, bis (cyclopentadienyl) zirconium bromide, bis (cyclopentadienyl) methyl zirconium monochloride, bis ( Cyclopentadienyl) ethyl zirconium monochloride, bis (cyclopentadienyl) cyclohexyl zirconium monochloride, bis (cyclopentadienyl) phenyl zirconium monochloride, bis (cyclopentadienyl) benzyl zirconium monochloride, bis (methylcyclo (Pentadienyl) zirconium dichloride, bis (pentamethylcyclopentadienyl) zirconium dichloride, bis (indenyl) zirconium Dichloride, bis (indenyl) zirconium dibromide, bis (cyclopentadienyl) zirconium dimethyl, bis (cyclopentadienyl) zirconium diphenyl, bis (cyclopentadienyl) zirconium dibenzyl, bis (cyclopentadienyl) methoxy zirconium Chloride, bis (cyclopentadienyl) ethoxyzirconium chloride, bis (cyclopentadienyl) butoxyzirconium chloride, bis (cyclopentadienyl) 2-ethylhexyloxyzirconium chloride, bis (cyclopentadienyl) methylzirconium ethoxide, Bis (cyclopentadienyl) methylethylzirconium butoxide, bis (cyclopentadienyl) ethylzirconium ethoxide, bis (cyclopentadienyl) phenyl Ruzirconium ethoxide, bis (cyclopentadienyl) benzylzirconium ethoxide, bis (methylcyclopentadienyl) ethoxyzirconium chloride, bis (indenyl) ethoxyzirconium chloride, bis (cyclopentadienyl) ethoxyzirconium, bis (cyclo (Pentadienyl) butoxyzirconium, bis (cyclopentadienyl) 2-ethylhexyloxyzirconium, bis (cyclopentadienyl) titanium monochloride monohydride, bis (cyclopentadienyl)
Titanium monobromide monohydride, bis (cyclopentadienyl) methyl titanium hydride, bis (cyclopentadienyl) ethyl titanium hydride, bis (cyclopentadienyl) cyclohexyl titanium hydride, bis (cyclopentadienyl)
Phenyltitanium hydride, bis (cyclopentadienyl) benzyltitanium hydride, bis (cyclopentadienyl) neopentyltitanium hydride, bis (methylcyclopentadienyl) titanium monochloride monohydride, bis (indenyl) titanium monochloride monohydride , Bis (cyclopentadienyl) titanium dichloride, bis (cyclopentadienyl) titanium bromide, bis (cyclopentadienyl) methyltitanium monochloride, bis (cyclopentadienyl) ethyltitanium monochloride, bis (cyclopentadiene) Enyl) cyclohexyltitanium monochloride, bis (cyclopentadienyl) phenyltitanium monochloride, bis (cyclopentadienyl) benzylthio Ammonium monochloride, bis (methylcyclopentadienyl) titanium dichloride, bis (indenyl) titanium dichloride, bis (indenyl) titanium dibromide, bis (cyclopentadienyl) titanium dimethyl, bis (cyclopentadienyl) titanium diphenyl, Bis (cyclopentadienyl) titanium dibenzyl, bis (cyclopentadienyl) methoxytitanium chloride, bis (cyclopentadienyl) ethoxytitanium chloride, bis (cyclopentadienyl) butoxytitanium chloride, bis (cyclopentadienyl) ) 2-ethylhexyloxytitanium chloride, bis (cyclopentadienyl) methyltitanium ethoxide, bis (cyclopentadienyl) methylethyltitanium butoxide, bis Cyclopentadienyl) ethyl titanium ethoxide, bis (cyclopentadienyl) phenyl titanium ethoxide,
Bis (cyclopentadienyl) benzyltitanium ethoxide, bis (methylcyclopentadienyl) ethoxytitanium chloride, bis (indenyl) ethoxytitanium chloride, bis (cyclopentadienyl) ethoxytitanium, bis (cyclopentadienyl) butoxy Titanium, bis (cyclopentadienyl) 2-ethylhexyloxytitanium, bis (cyclopentadienyl) hafnium monochloride monohydride, bis (cyclopentadienyl) hafnium monobromide monohydride, bis (cyclopentadienyl) methylhafnium Hydride, bis (cyclopentadienyl)
Ethylhafnium hydride, bis (cyclopentadienyl) cyclohexylhafnium hydride, bis (cyclopentadienyl) phenylhafnium hydride, bis (cyclopentadienyl) benzylhafnium hydride, bis (cyclopentadienyl) neopentylhafnium hydride, bis (Methylcyclopentadienyl) hafnium monochloride monohydride, bis (indenyl) hafnium monochloride monohydride, bis (cyclopentadienyl) hafnium dichloride, bis (cyclopentadienyl) hafnium bromide, bis (cyclopentadienyl) Methyl hafnium monochloride, bis (cyclopentadienyl) ethyl hafnium monochloride, bis (cyclopentadienyl) cyclohexyl Hafnium monochloride, bis (cyclopentadienyl) phenylhafnium monochloride, bis (cyclopentadienyl) benzylhafnium monochloride, bis (methylcyclopentadienyl) hafnium dichloride, bis (indenyl) hafnium dichloride, bis (indenyl) Hafnium dibromide,
Bis (cyclopentadienyl) hafnium dimethyl, bis (cyclopentadienyl) hafnium diphenyl, bis (cyclopentadienyl) hafnium dibenzyl, bis (cyclopentadienyl) methoxyhafnium chloride, bis (cyclopentadienyl) ethoxy Hafnium chloride, bis (cyclopentadienyl) butoxyhafnium chloride, bis (cyclopentadienyl) 2-ethylhexyloxyhafnium chloride, bis (cyclopentadienyl) methylhafnium ethoxide, bis (cyclopentadienyl) methethylhafnium Butoxide, bis (cyclopentadienyl) ethylhafnium ethoxide, bis (cyclopentadienyl) phenylhafnium ethoxide, bis (cyclopentadienyl) benzylhafnium ethate Sid, bis (methylcyclopentadienyl) ethoxyhafnium chloride, bis (indenyl) ethoxyhafnium chloride, bis (cyclopentadienyl) ethoxyhafnium, bis (cyclopentadienyl) butoxyhafnium, bis (cyclopentadienyl) 2 -Ethylhexyloxyhafnium, among these, bis (cyclopentadienyl) zirconium dichloride, bis (methylcyclopentadienyl) zirconium dichloride, bis (pentamethylcyclopentadienyl) zirconium dichloride, bis (indenyl) zirconium dichloride, etc. Can be preferably used.

The solid catalyst component of the present invention comprises at least the above transition metal compound supported on silicon oxide and / or aluminum oxide. As the silicon oxide used in the present invention, there is a double oxide of silica or silicon and at least one other metal of Groups I to VI of the periodic table. As the aluminum oxide used in the present invention, alumina or aluminum is used.
There are complex oxides with at least one other metal of Groups VI to VI.

[0013] Silicon or aluminum and Periodic Table I ~
Representative examples of complex oxides with at least one other metal of Group VI include Al ₂ O ₃ .MgO, Al ₂ O _3.
CaO, Al ₂ O ₃ .SiO ₂ , Al ₂ O ₃ .MgO
CaO, Al ₂ O ₃ .MgO.SiO ₂ , Al ₂ O _3.
CuO, Al ₂ O ₃ .Fe ₂ O ₃ , Al ₂ O ₃ .Ni
Various natural or synthetic double oxides such as O, SiO ₂ and MgO can be exemplified. Here, the above formula represents only the composition, not the molecular formula, and the structure and component ratio of the double oxide used in the present invention are not particularly limited. The silicon oxide and / or aluminum oxide (hereinafter referred to as “metal oxide”) used in the present invention is preferably used after calcining usually at 200 to 800 ° C., but may adsorb a small amount of water. It can be used without any problem even if it contains a small amount of impurities.

Whichever metal oxide is used, it is important that the metal oxide satisfies the following characteristics (A) to (E). (A) The average particle size measured by the sieving method is 20 to 150 μ
m, preferably 25-100 μm, more preferably 30
７０70 μm. When the average particle size is smaller than 20 μm,
Particularly, in the gas phase polymerization method, it is not preferable that the catalyst scatters from the reactor or the attached amount of the fine particle polymer increases to cause the formation of a sheet-like polymer, and that a problem such as a rise of the polymer occurs at the time of molding. On the other hand, if it is larger than 150 μm, the bulk density of the produced polymer decreases, and particularly when the polymer is used for a film, fish eyes increase, which is not preferable. (B) The specific surface area measured by the BET method is 150 to 600
m ² / g, preferably from 200 to 500 m ² / g, more preferably 250~400m ² / g. Specific surface area is 1
If it is less than 50 m ² / g, it depends on the catalyst component and composition to be supported, but in general, the catalyst component cannot be sufficiently supported, and if it is more than 600 m ² / g, on the contrary, the amount of surface hydroxyl groups Is too large, and a side reaction is likely to occur when the catalyst component is supported, and unreacted hydroxyl groups increase, which undesirably lowers the catalytic activity. (C) Pore radius 18 to 1,000 measured by mercury intrusion method
0.3-2.0 cm pore volume during 0 Å
³ / g, preferably 0.6 to 1.8 cm ³ / g, more preferably 0.9 to 1.5 cm ³ / g. The pore volume is 0.
If it is less than 3 cm ³ / g, the catalyst component cannot be sufficiently supported, and if it is more than 2.0 cm ³ / g, the catalyst component tends to be unevenly distributed, and in any case, the bulk density of the produced polymer decreases. (D) The apparent specific gravity measured according to JIS-K6220-6.8 is 0.35 or more, preferably 0.37 or more. If the apparent specific gravity is smaller than 0.35 , the container for preparing the solid catalyst component needs to be large, which is industrially disadvantageous. In addition, the bulk density of the prepared solid catalyst component also becomes low, and particularly when the solid catalyst component is supplied to the reactor as a powder in a gas phase polymerization method, the size of the supply device becomes large, which is industrially disadvantageous. Although the reason is not clear, the bulk density of the produced polymer tends to be low. (E) After the particles classified into the range of 53 μm or more and 75 μm or less by the sieving method are subjected to ultrasonic destruction treatment at 40 KHz and 35 W for 20 minutes, the particle ratio of 50 μm or less (ultrasonic destruction) is 30% or less. , Preferably 20% or less, more preferably 15% or less. If the amount of 50 μm or less after the ultrasonic destruction treatment is 30% or more (that is, it is easily broken), the metal oxide is broken by a stirring force when a catalyst is prepared using the metal oxide, which results in The solid catalyst component obtained has a poor shape, and as a result, the polymer formed from the solid catalyst component has a bad shape and a low bulk density.

Various methods for synthesizing the metal oxide used in the present invention are conceivable. Silica can be synthesized, for example, by the following method. 1) An aqueous alkali silicate solution and an aqueous acid solution are reacted to first produce a silica hydrogel, then coarsely crush the hydrogel using a dry impact mill, wet crush using a bead mill or pot mill, and spray the slurry. Dry using a dryer to obtain microsphere silica, and further, at about 200 ° C.
To remove water to obtain microsphere silica used in the present invention. Specifically, the alkali silicate as a raw material is converted into easily reactive silica recovered from clay raw materials such as sodium silicate and potassium silicate of water glass, which is JIS standardized as an industrial product, and acid clay. An alkali silicate or the like obtained by reacting a hydroxide solution of an alkali metal can be used. The SiO ₂ concentration in the aqueous alkali silicate solution is 6 to
It may be diluted in the range of 28% by weight, preferably about 10%, and the molar ratio of SiO ₂ : M ₂ O (M is an alkali metal) is usually 2: 1 to 4: 1, preferably 2.
It is desirable that the ratio be 5: 1 to 3: 1.

As the mineral acid used for the neutralization reaction, hydrochloric acid, sulfuric acid and the like are generally used, but a mixed acid thereof can also be used. The concentration of the mineral acid aqueous solution is usually 10 to 75% by weight,
Preferably, it is in the range of 20 to 60% by weight. The neutralization reaction by contacting both raw materials includes a method in which either raw material of both raw materials is added to the other solution with stirring, and a method in which both raw materials solutions are simultaneously contacted under certain conditions. It is desirable to use a method in which a prescribed amount of an acid is added, and an alkali silicate aqueous solution is injected with vigorous stirring to cause a reaction. The temperature at the time of neutralization is not particularly limited, but is usually 5
It is suitably 0 ° C. or lower, and the pH at the end of neutralization is in the range of 0 to 10. By this neutralization, a silica hydrosol is formed. The hydrosol is generally left for 30 minutes or more, and if necessary, the temperature of the reaction product (hydrosol),
It is gelled by adjusting the pH and converted into a silica hydrogel. SiO ₂ concentration in the hydrogel to be formed but typically those 5 to 30 wt% and less, in addition to the pores regulation of hydrogels, moisture regulation (SiO ₂ concentration increased) even heat treatment of the hydrogel according doubles, SiO ₂ It is desirable to use a silica hydrogel having a concentration of 5% or more. The temperature of this heat treatment is usually preferably 100 to 170 ° C., and can be performed in an autoclave. The silica hydrogel after the heat treatment is washed with water and, if necessary, filtered to obtain a solid hydrogel. Next, the mixture is roughly pulverized so that the particle size is usually 20 to 100 μm, and the coarse pulverized product is subjected to the above-mentioned SiO ₂ concentration of 15 to 25.
After preparing a silica hydrosol slurry by weight, wet pulverization is performed. Such wet grinding is desirably performed under high-speed shearing, and a device capable of high-speed shearing is desirable. For example, a friction inner plate mill is suitably used. Next, the slurry is dried using a spray dryer as described above to obtain microsphere silica, and further dried at about 200 ° C. to remove water to obtain microsphere silica used in the present invention. In these steps, silica having the properties of the present invention can be produced by changing the wet pulverization conditions, spray drying conditions, and the like.

2) An aqueous solution of sodium silicate is passed through a cation exchange resin layer, and SiO ₂ / Na ₂ O (molar ratio) 60
~ 130 sols are obtained, which are heated and aged to grow into independent dispersed particles having a large density, and the diluted sol obtained through the ion exchange resin layer is gradually added to the sol to polymerize on the surface of the independent dispersed particles. Deposit to obtain a stable sol. At this time, NaOH, LiOH or KO is used as a stabilizer.
H or the like may be added. After diluting the obtained stable sol to an appropriate concentration, spherical microsphere silica is obtained by spray drying, and further dried at about 200 ° C. to remove water to obtain microsphere silica used in the present invention. Of the above methods, the method 1) is preferred.

Alumina can be synthesized, for example, by the following method. 1) A carbonate is added to an aqueous solution of aluminum sulfate to form a basic aluminum sulfate, which is dropped into oil at a predetermined injection rate to form a sol into a spherical shape by surface tension, and then heated to obtain an alumina hydrogel. The spherical hydrogel is transferred from the oil layer to the aqueous layer and hydrolyzed, then desulfated, washed with water, and dried, and further at 500 to 600 ° C.
By calcination, a spherical alumina gel having a predetermined particle size is obtained. 2) Bauxite is extracted with sodium hydroxide and filtered to obtain sodium aluminate, which is hydrolyzed to aluminum hydroxide, pulverized and calcined to obtain an alumina gel. 3) The intermediate product of the above 2), aluminum hydroxide or a high alumina clay mineral, is reacted with sulfuric acid to form aluminum sulfate, neutralized with ammonia to precipitate aluminum hydroxide, filtered, dried and calcined. To obtain an alumina gel. Of the above methods, the method 1) is preferred.

The following method can be used for silica / alumina. 1) Sulfuric acid is put into a mixer, and sodium silicate is added dropwise while cooling with stirring to obtain a silica sol of PH1 to PH3. Calcium carbonate powder is gradually added to the separately stirred aqueous solution of aluminum sulfate to form a basic aluminum sulfate sol. 2-1 to 100 parts by volume of the silica sol
5 parts by volume of a basic aluminum sulfate sol are added and mixed, and the mixed sol is dropped into a heated organic solvent. At this time, the sol becomes spherical due to surface tension and then hydrogels. The spherical hydrogel is washed with water to remove ions and then dried to obtain a spherical silica-alumina gel. 2) sodium silicate, sodium aluminate, silica gel, suitable in the sodium hydroxide or the like 80 to 120 ° C. Na ₂
O / SiO ₂ molar ratio, SiO ₂ / Al ₂ O ₃ molar ratio, H
_{A 2} O / Na ₂ O molar ratio is selected and reacted for several hours to crystallize, then washed with water and dried. Of the above methods, the method 1) is preferred. In addition, before using the said metal oxide as a solid catalyst component, it is preferable to bake further at 200-800 degreeC.
Silica is particularly preferred among the above-mentioned silica, alumina and silica / alumina.

The above-mentioned metal oxides can, of course, be used as they are as components of the present invention. However, as a pretreatment, these carriers are treated with trimethylaluminum, triethylaluminum, triisobutylaluminum, tri-n-hexylaluminum, dimethylaluminum chloride. After contacting with an organoaluminum compound such as diethylaluminum chloride, diethylmonoethoxyaluminum, or a modified organoaluminum compound containing an Al—O—Al bond (this compound will be described later), or a silane compound, it is used. You can also. Further, alcohol, active hydrogen-containing compounds such as aldehydes, electron-donating compounds such as esters and ethers, alkoxide group-containing compounds such as tetraalkoxysilicate, tetraalkoxyaluminum, and transition metal tetraalkoxide, etc., before contacting The method used is also preferably used.

As the contact treatment method, an aromatic hydrocarbon (generally having 6 to 12 carbon atoms) such as benzene, toluene, xylene, ethylbenzene, heptane, hexane, decane, or the like is generally used in an inert atmosphere such as nitrogen or argon. A method in which a carrier is contacted with a compound for pretreatment under stirring or non-stirring in the presence of a liquid inert hydrocarbon such as an aliphatic or alicyclic hydrocarbon (generally having 5 to 12 carbon atoms) such as dodecane and cyclohexane. Is mentioned. This contact is usually performed at -100 ° C to 200 ° C, preferably -50 ° C to
At a temperature of 100 ° C. for 30 minutes to 50 hours, preferably 1 hour
It is desirable to carry out for about 24 hours.

This contact reaction is carried out in a solvent in which the above-mentioned compound for pretreatment is soluble, ie, benzene, toluene,
It is preferable to carry out the reaction in an aromatic hydrocarbon such as xylene or ethylbenzene (usually having 6 to 12 carbon atoms). In this case, after the contact reaction, without removing the solvent, it is used as it is to prepare the catalyst component of the present invention. Can be provided. Further, a liquid inert hydrocarbon in which the pretreatment compound is insoluble or hardly soluble in the contact reaction product (for example, when the pretreatment compound is a modified organoaluminum compound, pentane, hexane, decane, dodecane, cyclohexane Such as aliphatic or alicyclic hydrocarbons), and then precipitate and dry as a solid component, or remove a part or all of the aromatic hydrocarbons that are the solvent during the pretreatment by means of drying or the like. After that, it can be taken out as a solid component.

The ratio of the metal oxide to be subjected to the pretreatment and the compound for the pretreatment is not particularly limited as long as the object of the present invention is not impaired, but is usually 1 to 100 g of the metal oxide.
It is selected within the range of 1 to 10,000 mmol, preferably 5 to 1500 mmol (however, in the case of a modified aluminum compound, the Al atom concentration).

When the transition metal compound of Group IVB of the periodic table is supported on the metal oxide, an inert solvent may or may not be used when the transition metal compound is a liquid substance. When the compound is a solid at room temperature, it is generally preferable to use an inert solvent that can dissolve the transition metal compound. As the inert solvent that can be used at this time, an inert solvent that may be used when pretreating the metal oxide can be exemplified in the same manner. In particular, aromatic hydrocarbons such as benzene and toluene and halogenated hydrocarbons such as chlorobenzene are preferable.

The amount of the transition metal compound used in the above supporting reaction is 0.001 to 1 / g of the metal oxide.
The range is preferably 0 mmol, more preferably 0.005 to 5 mmol, and particularly preferably 0.01 to 1 mmol. The amount of the inert solvent used in the above-mentioned supporting reaction is in the range of 0.5 to 1000 ml, preferably 1 to 10 ml, particularly preferably 2 to 50 ml per gram of the metal oxide. In addition, the supporting reaction is carried out at a temperature in the range of 0 to 200 ° C., preferably 0 to 100 ° C., particularly 20 to 80 ° C., for 1 minute to 10 hours, 5 minutes to 5 hours, It can be carried out by contact mixing for 10 minutes to 3 hours. After carrying out the supporting reaction by the above-mentioned method, it is preferable to remove the liquid part in the reaction mixture by a method such as filtration or decantation, and further to wash it several times using an inert solvent.

In the solid catalyst component prepared by such a method, the transition metal compound is usually 0.005 to 5 mmol, preferably 0.01 to 1 mmol, particularly preferably 1 g of the solid catalyst component. Is contained in an amount of 0.03 mmol to 0.3 mmol. Of course, these catalyst components may further include other components, for example, compounds of Groups I to III of the periodic table, for example,
A catalyst component which is further contacted with a magnesium compound such as a magnesium halide or an organic magnesium compound, an aluminum compound such as an aluminum halide, an organic aluminum compound, an organic aluminum halide compound, or a lithium compound such as an organic lithium compound. May be used.

Modified organoaluminum compound The modified organoaluminum compound used in the present invention is a reaction product of an organoaluminum compound and water, and contains 1 to 100, preferably 1 to 100 in the molecule.
It contains 50 Al-O-Al bonds. The reaction between the organoaluminum and water is usually performed in an inert hydrocarbon. As the inert hydrocarbon, aliphatic, alicyclic and aromatic hydrocarbons such as pentane, hexane, heptane, cyclohexane, methylcyclohexane, benzene, toluene and xylene can be used, but aliphatic and aromatic hydrocarbons are preferred.

The above-mentioned organoaluminum compound has a general formula R _n AlX _3-n (R is a hydrocarbon group such as an alkyl group, an alkenyl group, an aryl group, an aralkyl group having 1 to 18 carbon atoms, preferably 1 to 12 carbon atoms, X represents a hydrogen atom or a halogen atom, and n represents an integer of 1 ≦ n ≦ 3), and trialkylaluminum is preferably used. The alkyl group of the trialkylaluminum may be any of a methyl group, an ethyl group, a propyl group, an isopropyl group, a butyl group, an isobutyl group, a pentyl group, a hexyl group, an octyl group, a decyl group, and a dodecyl group. Is particularly preferred.

The reaction ratio of water to the organic aluminum compound (water / Al molar ratio) is preferably from 0.25 / l to 1.2 / l, particularly preferably from 0.5 / l to 1/1. The reaction temperature is usually -70 to 100C, preferably -20 to 20C.
Range. The reaction time is generally selected in the range of 5 to 24 hours, preferably 10 to 5 hours. As the water required for the reaction, water of crystallization contained in copper sulfate hydrate, aluminum sulfate hydrate and the like can also be used.

According to the present invention, the olefin is polymerized or copolymerized in the presence of the catalyst comprising the above-mentioned catalyst component and the modified organoaluminum compound, but the catalyst component and the modified organoaluminum compound are mixed separately or in advance. And fed into the polymerization reaction system. In any case, the use ratio of the catalyst component and the modified organoaluminum compound is such that the atomic ratio of aluminum in the modified organoaluminum compound to the transition metal in the catalyst component is 1 to 10.
It is selected to be in the range of 0.000, preferably 5 to 1,000.

The method of the present invention can be applied to the production of various olefin polymers and olefin copolymers. Among them, α-olefins having 2 to 12 carbon atoms, for example, ethylene, propylene, 1-butene , 1-hexene, 4-methylpentene-1, etc., when homopolymerized, ethylene and propylene, ethylene and 1
-Ethylene and carbon number 3-1 such as butene, ethylene and 1-hexene, ethylene and 4-methylpentene-1.
It is suitably used when copolymerizing the α-olefin of No. 2, when copolymerizing propylene with 1-butene, or when copolymerizing ethylene with two or more other α-olefins.

For the purpose of modifying olefin polymers, diene compounds such as butadiene, 1,4-hexadiene, ethylidene norbornene and dicyclopentadiene are sometimes used as a copolymer component. The method of the invention can be applied.

The comonomer content in the copolymerization can be arbitrarily selected, but ethylene and α having 3 to 12 carbon atoms can be selected.
When the olefin is copolymerized with the olefin, the α-olefin content in the ethylene / α-olefin copolymer is 40 mol% or less, preferably 30 mol% or less, more preferably 20 mol% or less. It is desirable to do.

The polymerization reaction can be carried out by slurry polymerization, solution polymerization, or gas phase polymerization in the presence of the above-mentioned specific catalyst. In particular, slurry polymerization or gas phase polymerization is preferable, and hexane,
In the presence or absence of an inert hydrocarbon solvent selected from aliphatic hydrocarbons such as heptane, aromatic hydrocarbons such as benzene, toluene and xylene, alicyclic hydrocarbons such as cyclohexane and methylcyclohexane, olefins Is polymerized. The polymerization conditions at this time are as follows:
℃, preferably 50 ℃ ~ 100 ℃, pressure normal pressure ~ 70 kg
/ Cm ² G, preferably normal pressure to 20 kg / cm ² G, and the polymerization time is usually 5 minutes to 10 hours, preferably 5 minutes to 5 hours.

The molecular weight of the produced polymer can be adjusted to some extent by changing the polymerization conditions such as the polymerization temperature and the molar ratio of the catalyst, but the molecular weight can be more effectively adjusted by adding hydrogen to the polymerization reaction system. It can be carried out. Further, the method of the present invention is not limited to a polymerization mode, and can be applied to a multi-stage polymerization mode having two or more stages having different hydrogen concentrations and polymerization temperatures without any trouble.

[0036]

The present invention will be described in more detail with reference to the following Examples, which are merely illustrative of the present invention and do not limit the present invention. The average particle size, specific surface area, pore volume, apparent specific gravity, and ultrasonic destruction degree of the metal oxide used in the present invention were measured by the following methods.

<Average particle size> Standard sieve 10 having an inner diameter of 75 mm
(Nominal size 22, 32, 53, 75, 100, 12
5,150,180,212,250 μm each), shake for 20 minutes, plot the weight% of the sample on each sieve on log probability paper, and integrate 50% The particle size indicated by was defined as the average particle size. <Specific surface area> Automatic measuring device for specific surface area 22, manufactured by Shimadzu Corporation
It was measured by the BET method in accordance with a conventional method using Type 00. <Pore volume> Using a micromeritex autopore 9220 type manufactured by Shimadzu Corporation, pressure 0.033 to 42
Measured at 00 kg / cm ² , pore radius 18 to 1,000
The volume between angstrom was defined as the pore volume. <Apparent specific gravity> It was measured according to the apparent specific gravity measurement method of JIS K-6220-6.8. <Degree of ultrasonic destruction> Inner diameter 30cm, nominal size 53μm and 7
A sample (10 g) was placed on a 5 μm standard sieve, shaken for 10 minutes, and the sample on the 53 μm sieve was used for the following ultrasonic destruction test. 20 ml of pure water is put into a 50 ml Erlenmeyer flask, and 1 g of the sample on the above-mentioned 53 μm sieve is put into the flask.
20 with VO-CLEAR VS-50R ultrasonic cleaner
Sonicated for minutes. Next, 20 g of glycerin was added, and the particle size distribution was measured using a particle size distribution analyzer SA-CP3 manufactured by Shimadzu Corporation. The melting point of the polymer was measured by the following method. <Melting point> Using a DSC-20 melting point measuring apparatus manufactured by Seiko Denshi, a sample (5 mg) was kept at 180 ° C for 3 minutes, then cooled to 0 ° C at 10 ° C / min, and kept at 0 ° C for 10 minutes. Then, the melting point was measured by increasing the temperature at 10 ° C./min.

[Preparation of modified organoaluminum compound] 13 g of copper sulfate pentahydrate was placed in a 300 ml three-necked flask equipped with an electromagnetic induction stirrer, and suspended in 50 ml of toluene. Next, 150 ml of a 1 mmol / ml solution of trimethylaluminum was added dropwise to the suspension over 2 hours at a temperature of 0 ° C., and after the completion of the addition, the temperature was raised to 25 ° C. and reacted at that temperature for 24 hours. Thereafter, the reaction product was filtered to remove toluene in the liquid containing the reaction product, thereby obtaining 4 g of white crystalline methylalumoxane.

[Preparation of Solid Catalyst Component] The properties of the silicon compound and / or aluminum compound used in Examples and Comparative Examples are shown in Table 1.

Solid Catalyst Component A Purified toluene 100 was placed in a 300 ml three-necked flask.
Then, 10 g of silica having the properties shown in I of Table 1 was added, and 6.0 ml of a toluene solution of methylalumoxane (concentration: 2.5 mmol / ml) was further added, followed by stirring at room temperature for 2 hours. And dried by nitrogen blow to obtain fluid granules. 50 ml of toluene was added to a 300 ml three-necked flask, 10 g of the carrier component obtained above was added under nitrogen, and then a toluene solution of bis (cyclopentadienyl) zirconium dichloride (0.0%) was added.
(5 mmol / ml), and the mixture was stirred at room temperature for 2 hours. Thereafter, the solvent was removed under nitrogen blowing and reduced pressure,
A solid catalyst component was obtained.

Solid catalyst component B Solid catalyst component A is the same as solid catalyst component A except that silica having the property II in Table 1 is used in place of silica having the property I in Table 1. A solid catalyst component was prepared by the method.

Solid catalyst component C In the solid catalyst component A, bis (cyclopentadienyl)
A solid catalyst component was prepared in the same manner as for the solid catalyst component A except that 20 ml of a toluene solution of bis (indenyl) zirconium dichloride (0.05 mmol / ml) was used instead of the toluene solution of zirconium dichloride.

Solid catalyst component D In solid catalyst component A, bis (cyclopentadienyl)
A solid catalyst component was prepared in the same manner as the solid catalyst component A except that 20 ml of a toluene solution of bis (cyclopentadienyl) titanium dichloride (0.05 mmol / ml) was used instead of the toluene solution of zirconium dichloride. did.

Solid catalyst component E In solid catalyst component A, bis (cyclopentadienyl)
A solid catalyst component was prepared in the same manner as the solid catalyst component A except that 20 ml of a toluene solution of bis (cyclopentadienyl) hafnium dichloride (0.05 mmol / ml) was used instead of the toluene solution of zirconium dichloride. did.

Solid catalyst component F Solid catalyst component A was the same as solid catalyst component A except that silica having the properties V in Table 1 was used instead of silica having the properties I in Table 1. A solid catalyst component was prepared by the method.

Solid catalyst component G Solid catalyst component A was the same as solid catalyst component A except that silica having the property VI in Table 1 was used instead of silica having the property I in Table 1. A solid catalyst component was prepared by the method.

Solid Catalyst Component H Purified toluene 100 was placed in a 300 ml three-necked flask.
Then, 10 g of silica having properties shown in III of Table 1 was added, and 6.0 ml of a toluene solution of methylalumoxane (concentration: 2.5 mmol / ml) was further added, followed by stirring at room temperature for 2 hours. And dried by nitrogen blow to obtain fluid granules. 50 ml of toluene was added to a 300 ml three-necked flask, 10 g of the carrier component obtained above was added under nitrogen, 34 ml of a toluene solution of methylalumoxane (concentration 2.5 mmol / ml) was added, and bis (cyclopentane) was further added. Dienyl) zirconium dichloride in toluene solution (0.05 mmol / m
l) 20 ml was added and the mixture was stirred at room temperature for 2 hours. Thereafter, the solvent was removed under nitrogen blowing and reduced pressure to obtain a solid catalyst.

Solid catalyst component I Solid catalyst component F was the same as solid catalyst component F except that silica having the properties of IV in Table 1 was used instead of silica having the properties of III in Table 1. A solid catalyst component was prepared by the method.

Solid catalyst component J Purified hexane 100 was placed in a 300 ml three-necked flask.
Then, 10 g of silica having the properties shown in Table 1 III was added, and a hexane solution of triethylaluminum (concentration: 1.0 mmol / ml) was added to 10.0 g.
After stirring for 2 hours at room temperature, the mixture was dried by nitrogen blowing to obtain fluid granules. 50 ml of toluene was added to a 300 ml three-necked flask, 10 g of the carrier component obtained above was added under nitrogen, and then a toluene solution of methylalumoxane (concentration: 2.5 mmol / ml) was added to 40 ml.
ml of bis (cyclopentadienyl) zirconium dichloride in toluene solution (0.05 mmol).
/ Ml) and stirred at room temperature for 2 hours. Thereafter, the solvent was removed under nitrogen blowing and reduced pressure to obtain a solid catalyst.

Solid catalyst component K Purified butanol 10 was placed in a 300 ml three-necked flask.
After adding 0 ml, 10 g of silica having the properties shown in III of Table 1 was added, and the mixture was stirred at room temperature for 2 hours, and dried by blowing with nitrogen to obtain fluid granules. 300ml
50 ml of toluene, 10 g of the carrier component obtained above was added under nitrogen, and then a toluene solution of methylalumoxane (concentration: 2.5 mmol / m
l) was added, and a toluene solution of bis (cyclopentadienyl) zirconium dichloride (0.0
(5 mmol / ml), and the mixture was stirred at room temperature for 2 hours. Thereafter, the solvent was removed under nitrogen blowing and reduced pressure,
A solid catalyst was obtained.

Solid catalyst component L Solid catalyst component A was the same as solid catalyst component A except that silica having the properties of VII in Table 1 was used instead of silica having the properties of I in Table 1. A solid catalyst component was prepared by the method.

Solid catalyst component M Solid catalyst component H was the same as solid catalyst component H except that silica having the properties of VIII in Table 1 was used instead of silica having the properties of III in Table 1. A solid catalyst component was prepared by the method.

Solid catalyst component N Solid catalyst component K was the same as solid catalyst component K except that silica having the property IX in Table 1 was used instead of silica having the property III in Table 1. A solid catalyst component was prepared by the method.

Solid Catalyst Component O (Solid Catalyst Component for PP) Purified toluene 100 was placed in a 300 ml three-necked flask.
Then, 10 g of silica having the properties shown in I of Table 1 was added, and 6.0 ml of a toluene solution of methylalumoxane (concentration: 2.5 mmol / ml) was further added, followed by stirring at room temperature for 2 hours. And dried by nitrogen blow to obtain fluid granules. 50 ml of toluene was added to a 300 ml three-necked flask, 10 g of the carrier component obtained above was added under nitrogen, and a toluene solution of ethylenebis (indenyl) zirconium dichloride (0.05%) was added.
(mmol / ml), and the mixture was stirred at room temperature for 2 hours. Thereafter, the solvent was removed under nitrogen blowing and reduced pressure to obtain a solid catalyst component.

Solid Catalyst Component P (Solid Catalyst Component for PP) In the solid catalyst component O, a silica having a property II shown in Table 1 was used instead of the silica having a property I shown in Table 1. A solid catalyst component was prepared in the same manner as the solid catalyst component O.

Solid Catalyst Component Q (Solid Catalyst Component for PP) In the solid catalyst component O, the silica having the property of IX in Table 1 is used instead of the silica having the property of I in Table 1. A solid catalyst was prepared in the same manner as for the solid catalyst component O.

Example 1 A stainless steel autoclave equipped with a stirrer was used as a gas phase polymerization apparatus, and a loop was formed with a blower, a flow controller and a dry cyclone. The autoclave was heated by flowing hot water through a jacket. Was adjusted. 60 ° C
The solid catalyst component A was added to the autoclave adjusted to 10
0 mg / hr and a toluene solution of methylalumoxane (1 mmol / ml) were supplied at a rate of 30 mmol / hr, and the butene-1 / ethylene molar ratio in the gas phase of the autoclave was adjusted to be 0.25. Was supplied, the gas in the system was circulated by a blower while keeping the total pressure at 8 kg / cm ² G, and continuous polymerization was carried out for 10 hours while intermittently extracting the produced polymer.

The catalyst efficiency was 70,000 g copolymer / gZ
r and high activity. The produced ethylene copolymer had a melt flow rate (MFR) of 5.15 g / 10 min,
(Based on ASTM-D1238-65T, condition 190 ° C,
Load: 2.16 kg), density: 0.9205 g / cm ³ , bulk density: 0.45 g / cm ³ , average particle size: 460 μm
In the form of round granules. After the continuous polymerization for 10 hours, the inside of the autoclave was inspected. As a result, no polymer adhered to the inner wall and the agitator.

Examples 2 to 7 and Comparative Example 1 Polymerization was carried out in the same manner as in Example 1 using the solid catalyst components shown in Table 2. The results are shown in Table 2.

Example 8 Using the same apparatus as in Example 1, gas phase polymerization was carried out. 60
The solid catalyst H was added to an autoclave adjusted to 100 ° C. for 100 hours.
mg / hr, butene in the autoclave gas phase
The 1 / ethylene molar ratio was adjusted to 0.25, the gas in the system was circulated by a blower while maintaining the total pressure at 8 kg / cm ² G, and continuous polymerization was performed for 10 hours while intermittently extracting the produced polymer. went. The catalyst efficiency is 115,
The activity was as high as 000 g copolymer / gZr. The produced ethylene copolymer is melt flow rate (MFR)
5.22 g / 10 min, density 0.9203 g / cm ³
Having a bulk density of 0.47 g / cm ³ and an average particle size of 520.
It was a round granule having a shape of μm. After 10 hours of continuous polymerization, the interior of the autoclave was inspected.
No polymer adhered to the inner wall and the agitator.

Examples 9 to 11 and Comparative Examples 2 and 3 Polymerization was carried out in the same manner as in Example 8 using the solid catalysts shown in Table 2. The results are shown in Table 2.

Example 12 A 3-liter stainless steel autoclave equipped with a stirrer was replaced with nitrogen, and 1 liter of purified toluene was added thereto.
10 mmol of a toluene solution of methylalumoxane and 1 g of the solid catalyst component N were fed. 30 ℃ system temperature
The polymerization was started by injecting propylene to 3.5 kgf / cm ² G so that the total pressure was maintained at 3.5 kgf / cm ² G while continuously supplying propylene. Was done. After completion of the polymerization, the reaction gas was discharged and the system was cooled. The contents were taken out and the solvent was removed. As a result, 18 g of a white polymer was obtained. The catalyst efficiency was 28,000 g polymer /
High activity with gZr and bulk density of 0.45 g / cm ³
In this case, the particles were round and had an average particle diameter of 360 μm.
MFR was 5.1, density was 0.9038 g / cm ³ , and melting point was 140.9 ° C.

Example 13 and Comparative Example 4 Polymerization was carried out in the same manner as in Example 12 using the solid catalyst components shown in Table 3. The results are shown in Table 3.

[0064]

[Table 1]

[0065]

[Table 2]

[0066]

[Table 3]

────────────────────────────────────────────────── ─── Continued on the front page (56) References JP-A-63-89505 (JP, A) JP-A-63-61008 (JP, A) Chemical Society of Japan, Chemical Handbook (Application), Japan, Maruzen Stock Company, November 15, 1966, 2nd edition, 2nd printing, pp. 401-402 (58) Fields investigated (Int. Cl. ⁷ , DB name) C08F 4/60-4/70

Claims (3)

(57) [Claims] 1. A transition metal compound belonging to Group IV of the periodic table having at least a cycloalkadienyl ring and having a valence of 4
In a solid catalyst component for olefin polymerization in which a monovalent compound is supported on a silicon oxide and / or an aluminum oxide, the silicon oxide and / or the aluminum oxide have the following properties (A) to (E): A solid catalyst component for olefin polymerization characterized by satisfying. (A) The average particle size measured by the sieving method is 20 to 150 μ
m. (B) The specific surface area measured by the BET method is 150 to 600
m ² / g. (C) Pore radius 18 to 1,000 measured by mercury intrusion method
0.3-2.0 cm pore volume during 0 Å
³ / g. (D) The apparent specific gravity measured according to JIS-K6220-6.8 is 0.35 or more . (E) After the particles classified into the range of 53 μm or more and 75 μm or less by the sieving method are subjected to ultrasonic destruction treatment at 40 KHz and 35 W for 20 minutes, the particle ratio of 50 μm or less (ultrasonic destruction) is 30% or less. . 2. A transition metal compound of Group IV of the Periodic Table having at least a cycloalkadienyl ring, wherein the valence of the metal is 4
In a solid catalyst component for olefin polymerization in which a monovalent compound is supported on a silicon oxide and / or an aluminum oxide, the silicon oxide and / or the aluminum oxide have the following properties (A) to (E): Al-O- obtained by reacting a solid catalyst component for olefin polymerization, an organoaluminum compound and water, characterized by satisfying
An olefin polymerization catalyst comprising a modified organoaluminum compound containing an Al bond. (A) The average particle size measured by the sieving method is 20 to 150 μ
m. (B) The specific surface area measured by the BET method is 150 to 600
m ² / g. (C) Pore radius 18 to 1,000 measured by mercury intrusion method
0.3-2.0 cm pore volume during 0 Å
³ / g. (D) The apparent specific gravity measured according to JIS-K6220-6.8 is 0.35 or more . (E) After the particles classified into the range of 53 μm or more and 75 μm or less by the sieving method are subjected to ultrasonic destruction treatment at 40 KHz and 35 W for 20 minutes, the particle ratio of 50 μm or less (ultrasonic destruction) is 30% or less. . 3. A transition metal compound belonging to Group IV of the periodic table having at least a cycloalkadienyl ring and having a valence of 4
In a solid catalyst component for olefin polymerization in which a monovalent compound is supported on a silicon oxide and / or an aluminum oxide, the silicon oxide and / or the aluminum oxide have the following properties (A) to (E): Al-O obtained by reacting a solid catalyst component for olefin polymerization characterized by satisfying with an organoaluminum compound and water
-A method for producing a polyolefin, comprising polymerizing or copolymerizing an olefin in the presence of a catalyst comprising a modified organoaluminum compound containing an Al bond. (A) The average particle size measured by the sieving method is 20 to 150 μ
m. (B) The specific surface area measured by the BET method is 150 to 600
m ² / g. (C) Pore radius 18 to 1,000 measured by mercury intrusion method
0.3-2.0 cm pore volume during 0 Å
³ / g. (D) The apparent specific gravity measured according to JIS-K6220-6.8 is 0.35 or more . (E) After the particles classified into the range of 53 μm or more and 75 μm or less by the sieving method are subjected to ultrasonic destruction treatment at 40 KHz and 35 W for 20 minutes, the particle ratio of 50 μm or less (ultrasonic destruction) is 30% or less. .