JP2594381B2 - Method for producing polypropylene - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial application field) The present invention is excellent in workability, rigidity of a molded article, heat resistance,
Also, the present invention relates to a method for producing polypropylene having small warpage.

(Prior Art) Ziegler catalysts are well known as polymerization catalysts for propylene, and high stereoregularity catalysts which significantly improve the stereoregularity of polypropylene and have excellent activity are also well known. Polypropylene obtained using the above high stereoregularity catalyst has excellent stereoregularity, but has the disadvantage that the molecular weight distribution is wide, so that the molded article has high orientation strength, and the molded article has large warpage and distortion. doing.

In order to solve the above-mentioned problems of polypropylene having a wide molecular weight distribution, there has been known a method of narrowing the molecular weight distribution by melt-kneading with an organic peroxide. According to this method, the molecular weight distribution is narrowed, but at the same time, the molecular weight is reduced due to cleavage of the polymer chain by the organic peroxide, and properties such as rigidity and heat resistance are reduced.

Therefore, the present inventors have tried to produce a polypropylene having a relatively high molecular weight even after melt-kneading, using an ultrahigh molecular weight polypropylene as a melt-kneaded organic peroxide.

(Problems to be Solved by the Invention) Polypropylene having a relatively high molecular weight can be obtained by the above method, but its rigidity and heat resistance have not been sufficiently improved. The present inventors have conducted various studies on the cause, and found that ultra-high molecular weight polypropylene used for melt-kneading with organic peroxide contains a large amount of low molecular weight components, and this low molecular weight component is They have been found to be further decomposed to lower molecular weight, which leads to a decrease in rigidity and heat resistance.

(Means for Solving the Problems) Therefore, the present inventors think that the above problem can be solved by melt-kneading with an organic peroxide using ultra-high-molecular-weight polypropylene having a low molecular weight component. In addition, the inventors succeeded in synthesizing ultra-high-molecular-weight polypropylene having a small amount of low-molecular-weight components, and have proposed the present invention.

That is, the present invention provides a method of melt-kneading an ultrahigh molecular weight polypropylene having a weight average molecular weight of 1,000,000 or more and 7,000,000 or less and a component having a molecular weight of 10,000 or less and 1% by weight or less and an organized oxide. This is a method for producing polypropylene having excellent characteristics of rigidity and heat resistance and small warpage.

The ultrahigh molecular weight polypropylene used in the present invention is a propylene homopolymer or less than 5 mol% of α-olefins other than propylene such as ethylene, 1-butene, 1-hexene, 1-octene and 4-methyl-1 pentene. 95 mol%
Is more than a random copolymer with propylene.

The ultrahigh molecular weight propylene of the present invention has a weight average molecular weight
Over one million. When the weight average molecular weight is less than 1,000,000, when the molecular weight distribution is sufficiently narrowed by decomposition with an organic peroxide, a polypropylene having excellent rigidity and heat resistance cannot be obtained because the average molecular weight is too low. .

The weight average molecular weight of the ultrahigh molecular weight polypropylene used in the present invention may be 1,000,000 or more, but the average molecular weight is adjusted to a desired value while sufficiently narrowing the molecular weight distribution of the polypropylene after being decomposed with an organic peroxide. In order to
The ultra-high molecular weight polypropylene preferably has a weight average molecular weight of 7,000,000 or less. Furthermore, it is particularly preferable that it is in the range of 1.5 to 3,000,000.

The ultra-high molecular weight polypropylene used in the present invention has significantly less low molecular weight components. That is, gel permeation
In an elution curve measured by chromatography (GPC), an ultrahigh molecular weight polypropylene in which components having a molecular weight of 10,000 or less account for 1.0% by weight or less, and more preferably 0.5% by weight or less, is preferably used.

The ultrahigh molecular weight polypropylene used in the present invention is preferably highly crystalline in order to prevent a decrease in rigidity of the polypropylene after being decomposed with an organic peroxide. That is,
It is preferable that the P-xylene solubles be 1.0% by weight or less.

It is more preferable to use a very crystalline polypropylene having a P-xylene soluble content of 0.8% by weight or less, more preferably 0.6% by weight or less.

In addition, the above-mentioned P-xylene-soluble matter is a value measured by the method described later.

The tacticity of the ultrahigh molecular weight polypropylene used in the present invention greatly affects the crystallinity described above. The stereoregularity of the ultrahigh molecular weight polypropylene used in the present invention is ¹³ C-
Nuclear magnetic resonance spectrum (hereinafter abbreviated as ¹³ C-NMR)
It is preferably 0.96 or more, more preferably 0.97 or more, and even more preferably 0.98 or more, when expressed as a pentad fraction measured by the following formula.

D. Titanium-containing polypropylene obtained by preliminary polymerization E. Organoaluminum compound similar to B above F. Homopolymerization of propylene or propylene and α-olefin other than propylene in the presence of organosilicon compound similar to C above This is a method of performing copolymerization. As the titanium compound [A] used in the prepolymerization, a compound known to be used for the polymerization of olefins is employed without any limitation. In particular, a titanium compound having high catalytic activity containing titanium, magnesium and halogen as components is preferable. Such a titanium compound having a high catalytic activity,
Titanium halides, particularly titanium tetrachloride, are supported on various magnesium compounds. As a method for producing this catalyst, a known method is employed without any limitation. For example, JP-A-56-155206, JP-A-56-136806, and 57
JP-34103, JP-A-58-8706, JP-A-58-83006,
JP-A-58-138708, JP-A-58-183709, and 59-206408
JP-A-59-219311, JP-A-60-81208, JP-A-60-81208
No. 81209, JP-A-60-186508, JP-A-60-192708, JP-A-61-211309, JP-A-61-271304, JP-A-62-1
Nos. 5209, 62-11706, 62-72702,
The method disclosed in JP-A-62-104810 is adopted.
Specifically, for example, a method in which titanium tetrachloride is co-ground with a magnesium compound such as magnesium chloride, a method in which a titanium halide is mixed with a magnesium compound in the presence of an electron donor such as alcohol, ether, ester, ketone or aldehyde. Examples include a method of co-milling, and a method of catalyzing a titanium halide, a magnesium compound and an electron donor in a solvent.

Next, as the organoaluminum compound [B], a compound known to be used for polymerization of an olefin is employed without any limitation. For example, trialkyl aluminums such as trimethyl aluminum, triethyl aluminum, tri-n propyl aluminum, tri-n butyl aluminum, tri-i butyl aluminum, tri-n hexyl aluminum, tri-n octyl aluminum, and tri-n decyl aluminum; Examples thereof include diethylaluminum monohalides such as diethylaluminum monochloride; and alkylaluminum halides such as methylaluminum sesquichloride, ethylaluminum sesquichloride, and ethylaluminum dichloride.
In addition, alkoxyaluminums such as monoethoxydiethylaluminum and diethoxymonoethylaluminum can be used. Among them, triethylaluminum is most preferred. The amount of the organoaluminum compound used in each of the prepolymerization stages is Al to Ti atoms in the titanium compound.
/ Ti (molar ratio) is 1 to 100, preferably 2 to 20.

Further, as the organosilicon compound [C], the compound represented by the general formula [I] is employed without any limitation. R and R 'in the general formula [I] are hydrocarbons such as an alkyl group, an alkenyl group, an alkynyl group and an aryl group.
Examples of the organosilicon compound suitably used in the present invention are as follows. For example, trimethylmethoxysilane, trimethylethoxysilane, dimethyldimethoxysilane, dimethyldiethoxysilane, diphenyldimethoxysilane, methylphenyldimethoxysilane,
Diphenyldiethoxysilane, ethyltrimethoxysilane, methyltrimethoxysilane, vinyltrimethoxysilane, phenyltrimethoxysilane, methyltriethoxysilane, ethyltriethoxysilane, vinyltriethoxysilane, butyltriethoxysilane, phenyltriethoxysilane, And 6-triethoxysilyl 2-norbornene.

The amount of the organosilicon compound used in each prepolymerization step is 0.1 to Si / Ti (molar ratio) with respect to Ti atoms in the titanium compound.
100, preferably 0.5 to 10.

In the present invention, in addition to the titanium compound [A], the organoaluminum compound [B] and the organosilicon compound [C], the following general formula [II] R ″ -1 [II] It is preferable to use an iodine compound [D] represented by the following formula, since the crystallinity of the obtained ultrahigh molecular weight polypropylene is further increased.

In the general formula [II], the hydrocarbon group represented by R ″ is
Examples thereof include an alkyl group, an alkenyl group, an alkynyl group and an aryl group. Specific examples of the iodine compound that can be suitably used in the present invention are as follows. For example, iodine, methyl iodide, ethyl iodide, propyl iodide, butyl iodide, iodobenzene, p-iodine toluene and the like. Of these, methyl iodide and ethyl iodide are preferred. The amount of the iodine compound used in each prepolymerization step is 0.1 to 100, preferably 0.5 to 50 in terms of I / Ti (molar ratio) with respect to the titanium atom in the titanium compound.

In the present invention, performing prepolymerization in multiple stages means that propylene is prepolymerized in the presence of each of the components [A], [B], [C] and, if necessary, [D]. Titanium-containing polypropylene and the above [B], [C]
And that the prepolymerization of propylene is further repeated in the presence of each component [D] used as necessary. The prepolymerization is preferably performed in a range of 2 to 5 times. The above components used in each prepolymerization stage may be added sequentially or may be used as a batch. The polymerization amount of propylene in each prepolymerization step is in the range of 0.1 to 100 g, preferably 1 to 100 g, and industrially preferably in the range of 2 to 50 g per 1 g of the titanium compound.

In each prepolymerization step, different types of organosilicon compounds are used. As the organosilicon compound, a compound in which at least one of R and R 'in the general formula [I] is a bulky hydrocarbon group, for example, a phenyl group, a cyclohexyl group, a norbornyl group, or the like can be used. Is preferable because an ultrahigh molecular weight polypropylene of the formula (1) can be obtained.
The order of use of the organosilicon compounds used in each prepolymerization step is not particularly limited.

In each prepolymerization, propylene may be polymerized alone, and ethylene, 1-butene, 1-pentene, 1-hexene, 4-
An α-olefin other than propylene such as methylpentene-1 and propylene may be copolymerized. However, in consideration of improvement in stereoregularity, it is preferable to use propylene in an amount of 95 mol% or more. It is also possible to make hydrogen coexist at each prepolymerization stage.

It is preferable to apply slurry polymerization for each pre-polymerization, and use a saturated aliphatic or aromatic hydrocarbon such as hexane, heptane, cyclohexane, benzene or toluene alone or a mixed solvent thereof as a solvent. Can be. Each prepolymerization temperature is -20 to 100
C., especially 0-60.degree. C., and each stage of the prepolymerization may be carried out under different temperature conditions. The pre-polymerization time may be appropriately determined according to the pre-polymerization temperature and the amount of polymerization in the pre-polymerization, and the pressure in the pre-polymerization is not limited.
It is about 5 kg / cm ² G. Each prepolymerization is batch, half batch,
Any of continuous methods may be used. After completion of each prepolymerization, it is preferable to wash a saturated aliphatic hydrocarbon or an aromatic hydrocarbon such as hexane, heptane, cyclohexane, benzene, and toluene alone or with a mixed solvent. Six times is preferred.

After the above prepolymerization, main polymerization is performed. The main polymerization is
The reaction is carried out in the presence of a titanium-containing polypropylene, an organoaluminum compound, and an organosilicon compound obtained by the above prepolymerization.

As the organoaluminum compound used in the main polymerization, those used in the above-mentioned preliminary polymerization can be used, and most preferably, triethylaluminum is used. The amount of the organoaluminum compound used is 10 to 1000, preferably 50 to 5 in Al / Ti (molar ratio) with respect to the titanium atom in the titanium-containing polypropylene.
00.

Further, as the organosilicon compound, the compound represented by the general formula [I] is employed without any limitation. The amount of the organosilicon compound used in the main polymerization is 0.1 to 1000, preferably 0.5 to 500, in terms of Si / Ti (molar ratio) based on Ti atoms in the titanium-containing polypropylene.

Other polymerization conditions are not particularly limited as long as the effects of the present invention are recognized, but generally the following conditions are preferred. The polymerization temperature is from 20 to 200 ° C., preferably from 50 to 150 ° C., and hydrogen may be allowed to coexist as a molecular weight regulator. The polymerization can be applied to slurry polymerization, solventless polymerization, and gas phase polymerization, and may be any of batch, semi-batch, and continuous methods, and may be performed in two or more stages under different conditions. it can.

In the main polymerization, propylene may be polymerized alone, or ethylene, 1-butene, 1-pentene, 1-hexene, and α-olefin other than propylene such as 4-methylpentene-1 may be copolymerized with propylene. good. When the copolymerization is carried out, the composition of the monomer unit of the obtained ultra-high-molecular-weight polypropylene exceeds 95 mol% of the monomer unit based on propylene, and 5 mol of the monomer unit based on α-olefin other than propylene. % Copolymerization is carried out.

Further, for controlling the stereoregularity of olefins having 3 or more carbon atoms, electron donors such as ethers, amines, amides, sulfur-containing compounds, nitriles, carboxylic acids, acid amides, acid anhydrides and acid esters can coexist. .

In the present invention, the ultrahigh molecular weight polypropylene obtained by the above method is melt-kneaded in the presence of an organic peroxide. By this melt-kneading, a polypropylene having a narrow molecular weight distribution and arbitrarily adjusted molecular weight can be obtained. In performing the melt kneading, the ultrahigh molecular weight polypropylene and the organic peroxide are mixed, but the mixing method is not particularly limited. For example, a method of mechanically mixing using a blender such as a blender or a mixer, a method of dissolving an organic peroxide in an appropriate solvent, attaching the solution to ultra-high molecular weight polypropylene, and drying and mixing the solvent. There is.

As the melt kneading temperature, a temperature not lower than the melting temperature of polypropylene and not lower than the decomposition temperature of the organic peroxide is employed. However, if the heating temperature is too high, the polypropylene is thermally degraded. Generally, the melting temperature is 170-300 ° C, especially 180-2
It is preferable to set the temperature within the range of 50 ° C.

Known organic peroxides are generally used for the present invention. Representative organic peroxides include, for example, ketone peroxides such as methyl ethyl ketone peroxide and methyl isobutyl ketone peroxide; diacyl peroxides such as isobutyryl peroxide and acetyl peroxide; diisopropylbenzene hydroperoxide and other hydroperoxides. Oxide; 2,5
-Dimethyl 2,5-di- (t-butylperoxy) hexane, 1,3-bis- (t-butylperoxyisopropyl)
Dialkyl peroxide such as benzene; 1,1-di-t-
Butyl peroxy-cyclohexane and other peroxy ketals; alkyl peresters such as t-butyl peroxy acetate and t-butyl peroxy benzoate;
Butyl peroxyisopropyl carbonate, other percarbonates and the like can be mentioned. The amount of the organic peroxide to be used is not determined unequivocally depending on the set value of the melt index of the resulting polypropylene, but is 0.001 to 1.0 with respect to 100 parts by weight of the ultra-high molecular weight polypropylene.
Generally, parts by weight, preferably 0.01 to 0.5 parts by weight, are used.

The melt index of the polypropylene obtained by melt-kneading with the organic peroxide is 0.1 to 100 g / 10 minutes, and the molecular weight distribution at this time is the ratio of the weight average molecular weight to the number average molecular weight measured by GPC (w / n) is 4.0 or less, preferably 3.0
It is as follows. Further, in the polypropylene obtained by melt-kneading, generation of low molecular weight components is not substantially recognized,
The component having a molecular weight of 10,000 or less measured by GPC is 1.0% by weight or less like the ultrahigh molecular weight polypropylene before decomposition.
This is presumed to be the result of the decomposition by the organic peroxide selectively proceeding with respect to the high molecular weight component.

(Effect) The polypropylene obtained by the present invention has a very low molecular weight component and a very narrow molecular weight distribution, so that it is possible to obtain a molded article having excellent rigidity, heat resistance and warpage resistance, that is, a small warpage. it can.

(Examples) Hereinafter, the present invention will be described with reference to Examples and Comparative Examples, but the present invention is not limited to these Examples.

The measurement method used in the following examples will be described.

(1) Measurement of weight average molecular weight distribution and content of molecular weight of 10,000 or less It was measured by GPC (gel permeation chromatography) method. By Waters GPC-150C, o
Performed at 135 ° C. using dichlorobenzene as a solvent. The column used was Tosoh TSKgep GMH6-HT, gel size 10-1.
5μ. The calibration curve was prepared using polystyrene having a weight average molecular weight of 950,2900, 10,000, 50,000, 498,000, 2.7 million or 6.75 million as a standard sample.

(2) Melt index (hereinafter abbreviated as MI) ASTM D-
Compliant with 1238 (3) P-xylene-soluble component 1 g of polymer was added to 100 cc of P-xylene and stirred while stirring.
After the temperature was raised to 30 ° C., stirring was further continued for 30 minutes to prepare a uniform P-xylene solution. Then, it was left to cool to room temperature (23 ° C.) and left for 24 hours. The precipitated gel is filtered off, and
The amount of soluble matter was determined by completely concentrating the xylene solution.

P-xylene solubles (%) = P-xylene solubles (g)
It is represented by × 100.

(4) ¹³ C-NMR pentad fraction Macromolecules 6.925 (1973) by A. Zawbelli et al.
, That is, the fraction of 5 consecutive monomers in a polymer molecular chain which are bonded to each other isotactically using ¹³ C-NMR. The measurement was performed using JEOLGSX-270 with a pulse width of 90 °, a pulse interval of 15 seconds, and a total of 10,000 times. Peak assignment was performed according to Macromolecules 8.697 (1975).

(5) Apparent specific gravity Based on JIS K6721 (1977).

(6) Flexural modulus 63.6 mm by J120SA II injection molding machine of Japan Steel Works
A test piece of × 12.7 mm × 0.31 mm was prepared, and the test was performed according to ASTM: D-790.

(7) Thermal deformation temperature 63.6 mm by J120SA II injection molding machine of Japan Steel Works
A test piece of × 12.7 mm × 0.31 mm was prepared and the test was performed according to ASTM: D-648.

(8) Warp Nippon Steel Works J120SA II type 150 diameter by injection molding machine
A disc-shaped test plate of mm × 2.0 mm was prepared, placed on a flat plate after 48 hours, and the value obtained by dividing the maximum value H (max) of the vertical distance from the horizontal plane by the diameter of the disk was defined as warpage (%).

Warpage (%) = H (max) / diameter of disk × 100 Example 1 [Purification of Titanium Compound] The titanium component was adjusted according to the method of Example 1 in JP-A-58-83006. . That is, 0.95 g (10 mmol) of anhydrous magnesium chloride, 10 ml of decane, and 4.7 ml (30 mmol) of 2-ethylhexyl alcohol were heated and stirred at 125 ° C. for 2 hours, and then 0.55 g (3.75 mmol) of phthalic anhydride was added to this solution.
l) was added, and the mixture was further stirred and mixed at 125 ° C. for 1 hour.
A homogeneous solution was obtained. After cooling to room temperature, the whole amount was dropped into 40 ml (0.36 mmol) of titanium tetrachloride kept at 120 ° C. over 1 hour. After completion of the charging, the temperature of the mixture was raised to 110 ° C. over 2 hours. When the temperature reached 110 ° C., 0.54 ml (2.5 mmol) of diisobutyl phthalate was added, and the mixture was stirred at the same temperature for 2 hours. Held. After the completion of the reaction for 2 hours, a solid portion was collected by hot filtration, and the solid portion was 200 ml
Was re-suspended in TiCl ₄ and heated again at 110 ° C. for 2 hours. After the completion of the reaction, the solid portion was collected again by hot filtration, and sufficiently washed with decane and hexane until no free titanium compound was detected in the washing solution. The solid Ti catalyst component prepared by the above production method was stored as a heptane slurry. The composition of the solid Ti catalyst component is titanium
2.1% by weight, 57% by weight of chlorine, 18.0% by weight of magnesium,
And 21.9% by weight of diisobutyl phthalate.

(Preliminary polymerization)

In a single N ₂ -substituted autoclave, 200 ml of purified heptane, 50 mmol of triethylaluminum, 10 mmol of diphenyldimethoxysilane, 50 mmol of ethyl iodide and solid Ti
After the catalyst component was charged in an amount of 5 mmol in terms of Ti atom, propylene was continuously introduced into the reactor for 1 hour so as to be 5 g per 1 g of the solid Ti catalyst component, and the first prepolymerization was performed. The temperature during this period was kept at 15 ° C. One hour later, the introduction of propylene was stopped, and the inside of the reactor was sufficiently replaced with N ₂ . The solid portion of the resulting slurry was washed six times with purified heptane.

Further, this solid component was charged into a 1-autoclave subjected to N ₂ substitution, and 200 ml of purified heptane, 50 mmol of triethylaluminum, 10 mmol of 6-triethoxysilyl 2-norbornene, and 10 mmol of ethyl iodide were added. 1 g of the solid Ti catalyst component was continuously introduced into the reactor so as to be 5 g for 1 hour, and the second prepolymerization was performed. The temperature during this period was kept at 15 ° C. The solid part of the obtained slurry was washed six times with purified heptane to obtain a titanium-containing polypropylene.

(Main polymerization)

200 l of propylene was charged into a 400 l autoclave having an N ₂ substitution, and 274 mmol of triethylaluminum was added.
After charging 274 mmol of diphenyldimethoxysilane, the internal temperature of the autoclave was raised to 65 ° C., 1.1 mmol of titanium-containing polypropylene was charged as titanium atoms, and then the internal temperature of the autoclave was raised to 75 ° C. The polymerization of propylene was carried out for an hour. The polymerization pressure was 34 kg / cm ² , during which the temperature was kept at 75 ° C. After 3 hours, unreacted propylene was purged to obtain a white granular polymer (polymerized powder). The yield of the total polymer was 26 kg, and the activity at this time was 10 kg.
It was 400 g-PP / g-Cat.3Hr.

Polymer weight average molecular weight, melt index, P-
Xylene solubles, ¹³ C-NMR pentad fraction, GPC curve 1
Table 1 shows the weight% and apparent specific gravity of 10,000 or less.

The resulting white granular polymer was mixed with 1,3-bis- (t-butylperoxyisopropyl) -benzene as shown in Table 2, and further added with an antioxidant, a heat stabilizer and a chlorine scavenger. The mixture was added and mixed with a Hensiel mixer.

Next, the resin temperature at the die exit was 220 ° C using a 40mmφ extruder.
To obtain pellets.

 The results are shown in Table 2.

Example 2 In the main polymerization of Example 1, 200 l of propylene was charged, and 274 mmol of triethylaluminum and 274 mmol of diphenyldimethoxysilane were charged.
l% ethylene gas was charged, the internal temperature of the autoclave was raised to 65 ° C, and 1.1 mmol of titanium-containing polypropylene obtained by prepolymerization was charged as titanium atoms.
Subsequently, the internal temperature of the autoclave was raised to 70 ° C., and polymerization was performed for 3 hours. Ethylene gas was fed intermittently while checking with a gas chromatograph so that the ethylene concentration in the polymerization tank was maintained at 0.3 mol%. After 3 hours, unreacted monomers were purged to obtain a white granular polymer. After that,
Decomposition was carried out with an organic peroxide in the same manner as in Example 1.
The results are shown in Tables 1 and 2.

Examples 3 to 5 The same procedures as in Example 1 were carried out except that 10 ml (Example 3), 20 ml (Example 4) and 30 ml (Example 5) of hydrogen were used as molecular weight regulators in the main polymerization of Example 1. The same operation was performed. The results are shown in Tables 1 and 2.

Comparative Example 1 A catalyst component was prepared and propylene was polymerized according to the method described in Example 1 of JP-A-62-22808.
The results are shown in Tables 1 and 2.

Comparative Examples 2 and 3 The same operation as in Example 1 was carried out except that 80 ml (Comparative Example 2) and 120 ml (Comparative Example 3) of hydrogen were used as the molecular weight regulator in the main polymerization of Example 1. The results are shown in Tables 1 and 2.

Comparative Example 4 In the prepolymerization of Example 1, the same operation as in Example 1 was performed, except that the second prepolymerization was not performed. The results are shown in Tables 1 and 2.

Comparative Example 5 In the polymerization of Example 1, hydrogen was used as a molecular weight regulator.
400 ml was charged and polymerization was carried out. The weight average molecular weight of the obtained polypropylene is 250,000, and the melt index is 10
g / 10 minutes. To this, add only the antioxidant, heat stabilizer, and chlorine scavenger without adding organic peroxide.
The pellets were extruded with a φ extruder. The results are shown in Table 2.

Examples 6 and 7 The same operation as in Example 1 was performed, except that the organic peroxide was mixed with the polypropylene obtained in Example 1 as shown in Table 2. The results are shown in Table 2.

Examples 8 to 11 In the prepolymerization of Example 1, the organosilicon compound used in the second prepolymerization was 6-triethoxysilyl-2-
Instead of norbornene, phenyltriethoxysilane (Example 8), methyltriethoxysilane (Example 9), methylphenyldiethoxysilane (Example 10),
The same operation as in Example 1 was performed except that butyltriethoxysilane (Example 11) was used. Except for the above, decomposition was carried out with an organic peroxide in the same manner as in Example 1. The results are shown in Tables 3 and 4.

Example 12 [Preparation of titanium compound] The titanium compound was prepared according to the method of Example 1 in JP-A-62-104810.

That is, 100 g of aluminum trichloride (anhydrous) and 29 g of magnesium hydroxide were reacted while being ground at 250 ° C. for 3 hours using a vibration mill. After heating, cool in a nitrogen stream,
A solid product (I) was obtained.

In a glass flask, 15 ml of purified decane, 2.5 g of solid product (I), 8.5 g of n-butyl orthotitanate, and 9.8 g of 2-ethyl-1-hexanol were mixed, and stirred.
The mixture was dissolved by heating at 0 ° C. for 1.5 hours to obtain a uniform solution. The solution was brought to 70 ° C., 1.8 g of ethyl P-toluate was added, and the mixture was reacted for 1 hour. Then, 26 g of silicon tetrachloride was added dropwise with stirring over 2 hours to precipitate a solid, and the mixture was further stirred at 70 ° C. for 1 hour. . The solid was separated from the solution and washed with purified hexane to obtain a solid product (II).

1,2-dichloroethane 30 m in total amount of the solid product (II)
After adding 1.5 g of diisobutyl phthalate together with l and 30 ml of titanium tetrachloride and reacting with stirring at 100 ° C. for 2 hours, the liquid phase was removed by decantation at the same temperature.
Again, 30 ml of 1,2-dichloroethane, 30 ml of titanium tetrachloride and 1.5 g of diisobutyl phthalate were added, and the mixture was heated to 100 ° C. while stirring.
After reacting for an hour, a solid portion was collected by hot filtration, washed with purified hexane, and dried under reduced pressure at 25 ° C. for 1 hour to obtain a solid product (III).

The solid product (III) is spherical and has an average particle size of 15 μm
The particle size distribution was extremely narrow. This solid product (III) was used as a solid Ti catalyst component.

The results of composition analysis of the solid Ti catalyst component were as follows: Ti 3.0% by weight (hereinafter referred to as%), Cl 56,2%, Mg 17.6%, Al 1.7%, diisobutyl phthalate 20.1%, butoxy group 1.1% , 2-ethylhexynoxy group 0.2% and ethyl P-toluate 0.1%.

The subsequent prepolymerization and polymerization were carried out in the same manner as in Example 1. Table 5 shows the physical properties of the obtained polymer. The results of decomposition with an organic peroxide in the same manner as in Example 1 are shown in Table 6.

Example 13 [Preparation of titanium compound] The titanium compound was prepared according to the method of Example 1 in JP-A-62-11706.

Specifically, 50 ml of purified heptane, 50 ml of titanium tetrabutoxide, and 7.0 g of anhydrous magnesium chloride are added to a 500 ml three-neck glass flask (with a thermometer and a stirrer) having an internal volume of 500 ml, which is purged with nitrogen. Thereafter, the temperature of the flask was raised to 90 ° C., and magnesium chloride was completely dissolved over 2 hours. Next, the flask was cooled to 40 ° C., and 10 ml of methylhydrogenpolysiloxane was added to precipitate magnesium chloride and titanium tetshibutoxide complex. This was washed with purified heptane to give an off-white solid.

50 ml of a heptane slurry containing 10 g of the precipitated solid obtained above was introduced into a 300 ml three-neck glass flask (with a thermometer and a stirrer) having an internal volume of 300 ml and purged with nitrogen. Next, 20 ml of a heptane solution containing 5.8 ml of silicon tetrachloride was added over 30 minutes at room temperature, and further reacted at 30 ° C. for 45 minutes. 90 ° C
For 1.5 hours, and after completion of the reaction, washed with purified heptane. Next, 50 ml of a heptane solution containing 1.5 ml of diheptyl phthalate was added and reacted at 50 ° C. for 2 hours, followed by washing with purified heptane, and further adding 25 ml of titanium tetrachloride.
The reaction was performed at 90 ° C. for 2 hours. This was washed with purified heptane to obtain a solid Ti catalyst component.

The titanium content in the solid Ti catalyst component was 3.04% by weight. The subsequent prepolymerization and polymerization were performed in the same manner as in Example 1. Next, it was decomposed with an organic peroxide in the same manner as in Example 1. The results are shown in Tables 5 and 6.

Claims (1)

(57) [Claims] An ultrahigh molecular weight polypropylene having a weight average molecular weight of 1,000,000 or more and 7,000,000 or less and a component of a molecular weight of 10,000 or less of 1% by weight and an organic oxide are melt-kneaded. A method for producing polypropylene having excellent rigidity and heat resistance and low warpage.