JPH1180261A - Crystalline polypropylene - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a crystalline polypropylene having excellent moldability and rigidity both of which are kept in good balance. SOLUTION: This polypropylene is a crystalline polypropylene which satisfies the following requirements (1) to (3):(1) 0.5<MFR<200 wherein MFR represents a melt flow rate, (2) 90<HI wherein HI represents a weight ratio of the residue after extraction with boiling n-heptane for 6 hours by means of a modified Soxhlet extractor to the total polymer, and (3) 5 or more in terms of the value of A in the formula : A=0.8209×log (I) +9.481×log(G)+0.1616×(CT)-23.15 [wherein I represents a density of supherulite nuclei formed (unit: number/m<3> ) and G represents a growth rate for a (a increasing rate for a supherulite radius, unit: μm/min), and CT represents the temperature ( deg.C), as determined by differential scanning calorimetry, at which supherulite nuclei are formed wherein both of I and G are measured in the isothermal crystallization at 135 deg.C].

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a crystalline polypropylene, and more particularly to a crystalline polypropylene suitable for injection molding.

[0002]

2. Description of the Related Art Polypropylene is widely used in various fields such as various containers, daily necessities, automobile parts and electric parts because of its light weight and excellent rigidity and heat resistance. However, these properties are still insufficient depending on the purpose of use. Various methods for improving the rigidity have been proposed, but most of them are methods of performing post-treatment using an additive or the like (for example, JP-A-6-329726), which increases the cost in terms of process. . A method of improving rigidity by devising a polymerization method is also known (JP-A-6-329726), but is insufficient at present.

[0003]

As described above, the known polypropylene has an insufficient balance of moldability and rigidity depending on the use.

Accordingly, an object of the present invention is to provide a crystalline polypropylene having excellent balance between moldability and rigidity.

[0005]

The crystalline polypropylene of the present invention has the following properties. (1) The melt flow rate MFR is 0.5 <M
FR <200, and (2) the weight ratio HI of the residue to the total polymer after extraction with boiling n-heptane for 6 hours in a modified Soxhlet extractor satisfies 90 <HI, and
(3) Spherulite nucleation density I and spherulite growth rate G determined during spherulite growth during isothermal crystallization at 135 ° C., and spherulite nucleation temperature CT (° C.) determined by differential scanning calorimetry Is expressed by the following equation (i):

[0006]

A = 0.8209 × log (I) + 9.481 × log (G) + 0.1616 × (CT) -23.15 (i) (In the above formula, I is the number of spherulite nuclei per 1 mm ^3. And G is the rate of increase (μm) in spherulite radius (μm) per minute.
m / min) and CT is represented by the temperature (° C.) at which crystallization starts in differential scanning calorimetry), and the value of A is not less than 5.0. Preferred embodiments include the following: The above-mentioned crystalline polypropylene, wherein the MFR satisfies 0.7 <MFR <160. The above crystalline polypropylene, wherein the MFR satisfies 1.0 <MFR <120. Any of the above crystalline polypropylenes, wherein the HI satisfies 92 <HI. Any of the above crystalline polypropylenes, wherein the HI satisfies 94 <HI. Any of the above crystalline polypropylenes, wherein in the formula (i), A is a value larger than 6.0. Any of the above crystalline polypropylenes, wherein in the formula (i), A is a value larger than 7.0.

[0007]

BEST MODE FOR CARRYING OUT THE INVENTION The crystalline polypropylene of the present invention has a melt flow rate MFR of 0.5 <MFR <
It is necessary to meet 200. The MFR is preferably
Greater than 0.7, more preferably greater than 1.0. Also, the MFR is preferably less than 160, more preferably
Less than 120. When the MFR is less than 0.5, the fluidity and moldability deteriorate, and when the MFR is more than 200, the strength, particularly the impact resistance, decreases. Here, the melt flow rate (M
FR) is at 230 ° C under a load according to ASTM D1238.
It is measured under the condition of 2.16 kg, and the unit is g / 10 minutes (the same applies to the following). The crystalline polypropylene of the present invention must have an HI satisfying 90 <HI. The HI is preferably 92 <HI, more preferably 94 <
Meet HI. When the HI is 90 or less, the rigidity is reduced. Here, HI is the content of heptane-insoluble matter, and the crystalline polypropylene is boiled with a modified Soxhlet extractor.
It is a weight ratio of the residue (ie, heptane-insoluble matter) after extraction with n-heptane for 6 hours, based on the entire crystalline polypropylene.

The crystalline polypropylene of the present invention has a temperature of 135 ° C.
When isothermal crystallization is performed, the spherulite nucleation density I (unit: pieces / mm ³ ) and spherulite growth rate G (unit: μm / min) measured in the course of spherulite growth, and differential scanning calorimetry The relationship between the determined spherulite nucleation temperature CT (° C.)
The following equation (i):

[0009]

A = 0.8209 × log (I) + 9.481 × log (G) + 0.1616 × (CT) -23.15 (i) (where I is the number of spherulite nuclei per 1 mm ³ And G is the rate of increase (μm) in spherulite radius (μm) per minute.
m / min) and CT (expressed as the temperature (° C.) at which crystallization starts in differential scanning calorimetry), the value of A needs to be at least 5.0. A
Is preferably greater than 6.0, more preferably greater than 7.0. If the value of A is less than 5.0, the balance between rigidity and moldability will be poor.

In this specification, the spherulite nucleus generation density I and the spherulite growth rate G are determined as follows.
That is, the crystalline polypropylene of the present invention is isothermally crystallized at 135 ° C., and the growth process of spherulites is observed using an optical microscope. The sample is first kept at 220 ° C for about 15 minutes,
It is desirable to rapidly cool to 135 ° C. Unit volume (1m
The number of spherulites generated per m ³ ) is counted to determine the spherulite nucleation density, and the slope of a straight line obtained by plotting the radius of the grown spherulites against the elapsed time is expressed in unit time (minutes).
Per spherulite radius per unit (μm).

The spherulite nucleation temperature CT was determined as follows. That is, differential scanning calorimetry is performed on crystalline polypropylene. First, the sample is kept at 220 ° C. for about 15 minutes, and then cooled at a constant rate (for example, 10 ° C./min) to create a chart showing the relationship between the temperature and the amount of heat per unit time. From the obtained chart, the temperature at which crystallization starts is determined, and this is determined as the spherulite nucleation temperature CT (° C.).
And

When I, G and CT are represented by the relationship (i), when A is 5.0 or more, a crystalline polypropylene excellent in rigidity and moldability with good balance can be obtained.

The method for producing the crystalline polypropylene of the present invention is not particularly limited. For example, a method described in detail in Japanese Patent Application Laid-Open No. Hei 7-133319, that is, using a magnesium chloride-supported stereoregular catalyst, and It is preferable to produce by a method combining silane addition prepolymerization and silane addition main polymerization. In this method, (a) a solid component containing magnesium, titanium, halogen and an electron donating compound as essential components is converted into (d) in the presence of (b) an organoaluminum compound and (c) an organosilicon compound. ) Polymerization of propylene (main polymerization) using a catalyst component obtained by contact with olefin (preliminary polymerization).

The solid component (a) is prepared, for example, by contacting a magnesium compound, a titanium compound and an electron donating compound. When none of the above compounds contains a halogen atom, a halogen compound is added thereto and brought into contact. Examples of the magnesium compound include dialkyl magnesium such as Mg (CH ₃ ) ₂ ;
A diarylmagnesium such as (C ₆ H ₅ ) ₂ ; Mg (O
Dialkoxy magnesium such as C ₄ H ₉ ) ₂ ; Mg (O
Diaryloxymagnesium such as C ₆ H ₅ ) ₂ ; C ₂
Alkyl magnesium halides such as H ₅ MgBr; C
Aryl halides such as magnesium ₆ H ₅ MgCl;
(C ₄ H ₉ O) Alkoxy magnesium halide such as MgBr; (C ₆ H ₅ O) aryloxy magnesium halide such as MgCl; magnesium halide such as MgCl ₂ . Magnesium compounds are
(A) When preparing a solid component, it can be prepared from metallic magnesium. As the titanium compound, a divalent, trivalent or tetravalent titanium compound can be used, and specific preferred examples include titanium tetrachloride, trichloroethoxytitanium, dichlorodibutoxytitanium, and dichlorodiphenoxytitanium. Examples of the electron donating compound include carboxylic acids and derivatives thereof (anhydrides, esters, halides, etc.), alcohols, phenols, ethers, ketones, amines, amides, nitriles, aldehydes, alcoholates And the like. Examples of the halogen compound include halogenated hydrocarbons such as methyl chloride; halogenated alcohols such as chloroethanol; halogenated phenols such as bromophenol; HSiCl ₃
And the like; metal halides and the like. The contact of the compound is carried out by mixing and stirring or mechanically co-milling in the presence or absence of an inert medium (for example, hexane, heptane, cyclohexane, benzene, toluene, etc.). It can be performed under heating at 150 ° C. (A) The solid component is preferably prepared by a method disclosed in detail in JP-A-63-264607, JP-A-58-198503 and JP-A-62-146904. More specifically, (a) metal magnesium, (b) halogenated hydrocarbon, (c) a compound of the general formula X _n M (OR) _mn (X is a hydrogen atom, a halogen atom or a C ₁ -C ₂₀ hydrocarbon; M is B, C, Al, Si or P; R is a C ₁ -C ₂₀ hydrocarbon; m is the valency of M, m> n ≧ 0), and the magnesium-containing solid obtained by contacting with (d) halogen (E) contact with an electron-donating compound and (f) a titanium compound.
JP-A-264607), (a) contacting a magnesium dialkoxide with a (ii) silicon halide compound having a hydrogen-silicon bond, (c) contacting a titanium halide compound, and then (d) electron donating Contacting with a compound (if necessary, further contacting with a titanium halide compound)
62-146904), (a) contacting a magnesium dialkoxide with (b) a silicon halide compound having a hydrogen-silicon bond, (c) contacting with an electron-donating compound, and then (d)
This is a method in which a titanium compound is brought into contact (JP-A-58-198503).

[0015] Of these, a particular method is most desirable.

In the prepolymerization, the solid component (a) is
Contacting with (d) olefin (for example, α-olefin such as ethylene, propylene, butene, etc.) in the presence of (b) organoaluminum compound and (c) organosilicon compound. Examples of the organic aluminum compound include trimethylaluminum, triethylaluminum, triisobutylaluminum, and trihexylaluminum. Examples of the organosilicon compound include bis (oxacyclopent-3-yl) dimethoxysilane, dimethoxymethyl-2-oxacyclohexylsilane, 2,3,4-trimethyl-3-azacyclopentyltrimethoxysilane,
Isopropoxycyclopentyldimethoxysilane, sec-
Butoxycyclopentyldimethoxysilane, cyclohexylmethyldimethoxysilane, dicyclopentyldimethoxysilane, t-butoxycyclopentyldimethoxysilane, t-amyloxycyclopentyldimethoxysilane,
-sec- butoxypropyldimethoxysilane and the like. In addition, it is preferable to add an electron donating compound at the time of preliminary polymerization, if necessary. As such an electron donating compound, for example, organosilicon compounds such as tetramethoxysilane, tetraphenoxysilane, and vinyltriethoxysilane are preferable.

The prepolymerization is preferably carried out in the presence of an inert medium, usually at a temperature of 100 ° C. or lower. The polymerization system may be a batch system or a continuous system, and may be performed in one stage or in two or more stages. Preferably, the concentration of (b) the organoaluminum compound in the prepolymerized system is 10
Used to be ~ 500 mmol / l,
(A) It is used in an amount of 1 to 50,000 mol per 1 g of titanium in the solid component. (C) The organosilicon compound is used so that the concentration in the prepolymerized system is 5 to 1000 mmol / L. The olefin polymer is incorporated into the solid component (a) by the prepolymerization, and the amount of the polymer is preferably 0.1 to 200 g per 1 g of the solid component (a).

[0018] The catalyst component thus prepared can be diluted or washed with an inert medium. After washing, it may be dried.

Alternatively, the solid component (a) of the above catalyst
In the above, a catalyst further containing a metal oxide can also be used. The metal oxide is an oxide of an element selected from the group of elements of Groups II to IV of the Periodic Table of the Elements,
For example, B ₂ O ₃ , MgO, Al ₂ O ₃ ,
SiO ₂ , CaO, TiO ₂ , ZnO, ZrO ₂ , Sn
O ₂ , BaO, ThO _{2 and the} like can be mentioned. Among them, B ₂ O ₃ , MgO, Al ₂ O ₃ , SiO ₂ , Ti
O ₂ and ZrO ₂ are preferred, and SiO ₂ is particularly preferred.
Further, composite oxides containing these metal oxides, for example, S
_{iO 2 -MgO, SiO 2 -Al 2} O 3, SiO 2 -T
iO ₂ , SiO ₂ -V ₂ O ₅ , SiO ₂ -Cr ₂ O ₃ ,
SiO ₂ —TiO ₂ —MgO or the like can also be used.

These metal oxides are usually used in the form of powder. Since the form such as the size and shape of the powder often affects the form of the obtained olefin polymer, it is desirable to appropriately adjust the form. It is desirable that the metal oxide be fired at as high a temperature as possible for the purpose of removing poisonous substances when used, and that the metal oxide be handled so as not to come into direct contact with the atmosphere.

When a metal oxide is contained, a preferred method for preparing the component (a) is described in JP-A-58-162607 and JP-A-55-9
No. 4909, No. 55-115405, No. 57-108107, No. 61-21109, No. 61-174204, No. 61-174
Methods disclosed in JP-A-205, JP-A-61-174206, and JP-A-62-7706 are exemplified. More specifically, a method in which a reaction product of a metal oxide and a magnesium dialkoxide is brought into contact with an electron-donating compound and a tetravalent titanium halide (JP-A-58-162607); A method in which a reaction product of a hydrocarbyl halide compound is contacted with a Lewis base compound and titanium tetrachloride (JP-A-55-94909). A reaction product of a porous carrier such as silica and an alkylmagnesium compound is treated with titanium. A method of contacting with an electron-donating compound and a silicon halide compound before contacting with a compound (JP-A-55-115405 and JP-A-57-108107), metal oxides, alkoxy-containing magnesium compounds,
A method of contacting an aromatic polycarboxylic acid having a carboxyl group at the ortho position or a derivative thereof and a titanium compound (JP-A-61-174204), a metal oxide, an alkoxy group-containing magnesium compound,
A method of contacting a silicon compound having a hydrogen-silicon bond, an electron donating compound and a titanium compound (JP-A-61-1)
No. 74205) Metal oxide, alkoxy-containing magnesium compound,
A method in which a halogen element or a halogen-containing compound, an electron-donating compound and a titanium compound are brought into contact (Japanese Patent Application Laid-Open No.
-174206), a method of contacting a reaction product obtained by contacting a metal oxide, dihydrocarbylmagnesium and a halogen-containing alcohol with an electron-donating compound and a titanium compound (JP-A-61-21109), A method in which a solid obtained by contacting a metal oxide, hydrocarbyl magnesium and a hydrocarbyloxy group-containing compound (corresponding to the alkoxy group-containing compound) is contacted with a halogen-containing alcohol, and further contacted with an electron-donating compound and a titanium compound ( JP
62-7706). Of these, methods (1) and (2) are particularly desirable.

Using the catalyst component thus obtained, propylene is polymerized (main polymerization reaction), if necessary, in combination with an organometallic compound and / or an electron donating compound. As the organometallic compound, Li, Mg, Ca, Z
Organic compounds of n and Al can be used. Of these, organoaluminum compounds are particularly preferable, for example, trialkylaluminums such as trimethylaluminum, triethylaluminum, and triisobutylaluminum; dialkylaluminum monohalides such as diethylaluminum chloride; monoalkylaluminum dihalides such as ethylaluminum dibromide; Alkyl aluminum sesquihalides such as chloride; dialkyl aluminum monoalkoxides such as dimethyl aluminum methoxide; dialkyl aluminum hydrides such as diisobutyl aluminum hydride. Examples of the electron donating compound include dimethoxymethyl-2-oxacyclohexylsilane, 2,3,4-trimethyl-3-azacyclopentyltrimethoxysilane,
Bis (oxacyclopent-3-yl) dimethoxysilane, isopropoxycyclopentadienyldimethoxysilane, t-butoxycyclopentadienyldimethoxysilane, isopropoxycyclopentyldimethoxysilane,
Organic silicon compounds such as sec-butoxycyclopentyldimethoxysilane, cyclohexylmethyldimethoxysilane, dicyclopentyldimethoxysilane, t-butoxycyclopentyldimethoxysilane, t-amyloxycyclopentyldimethoxysilane, and di-sec-butoxypropyldimethoxysilane.

The present polymerization reaction is carried out in a gas phase or a liquid phase (for example, in an inert hydrocarbon such as butane, isobutane, cyclohexane, benzene, toluene and in a liquid monomer).
The polymerization can be carried out at a polymerization temperature of -80 to + 150 ° C and a polymerization pressure of 1 to 60 atm. The polymerization reaction may be a batch type or a continuous type,
Further, it may be performed in one stage or in two or more stages.
In order to control the molecular weight of the produced polymer, a known molecular weight regulator such as hydrogen can be present in the polymerization reaction system. By changing the type and amount of the molecular weight modifier, a polypropylene having a desired MFR can be obtained.

The crystalline polypropylene of the present invention can be used as a composition containing conventional additives. Conventional additives that can be used in combination include, for example, antioxidants, heat stabilizers,
Examples include light stabilizers, flame retardants, plasticizers, antistatic agents, lubricants, mold release agents, nucleating agents, fillers, and the like.

[0025]

The present invention will be described in more detail with reference to the following examples. The percentages are by weight unless otherwise specified.

The MFR was measured at 230 ° C. under a load of 2.16 kg in accordance with ASTM D1238. HI
The (heptane-insoluble content) was determined as a weight ratio of the residue after extracting the sample with boiling n-heptane for 6 hours using a modified Soxhlet extractor with respect to the whole sample. The flexural modulus is
It was measured according to JIS K-6758. 135 ° C
The spherulite nucleation density I and the spherulite growth rate G in the course of spherulite growth by isothermal crystallization at room temperature were measured as follows: Approximately 5 mg of sample (FIG. 1, d) was covered with a cover glass (FIG. 1, d). c) at 220 ° C. in apparatus 1 (FIG. 1, a)
After holding for 15 minutes, the mixture was rapidly cooled and kept at 135 ° C. While maintaining the temperature at 135 ° C., the apparatus 1 was inserted into the apparatus 2, and the spherulite growth process was observed by the apparatus 2 (FIG. 1, b). Temperature 13
After 2 minutes or more from 5 ° C, 280μm × 3
The number of spherulites generated in a rectangular parallelepiped region of 70 μm × 100 μm was counted. The same was performed in four regions of the same size, and the average of four measurements was obtained. This value is taken as the unit volume (1mm
³ ) The number of spherulite nuclei was converted to the number of spherulites. In addition, three arbitrary spherulites were selected, the amount of increase in the radial direction of each spherulite was measured, and three average values were obtained. This was expressed as an increase (μm / min) per unit time (1 minute), and was defined as a spherulite growth rate G. The device 1 and the device 2
Used the following. Equipment 1: Hot stage equipment METTLER FP80HT, temperature control ± 0.1
° C; device 2: optical microscope, measurement magnification 200 times, transmission type,
No polarization.

The spherulite nucleation temperature CT was measured as follows: Approximately 10 mg of sample was taken using a differential scanning calorimeter (DSC).
(Perkin-Elmer, DSC-
4) Put in the pan and keep at 220 ° C for 15 minutes.
The temperature was lowered at a rate of one minute, and a chart showing the relationship between the temperature and the amount of heat per unit time was created. From the obtained chart, the temperature at which crystallization starts (the temperature at which the amount of heat starts to decrease) was determined, and this was defined as the spherulite nucleation temperature CT (° C.).

Example 1 Preparation of Polymerization Catalyst Component A1 In a 1 liter reaction vessel equipped with a reflux condenser, chip-shaped metallic magnesium (purity 99.5%,
8.3 g of an average particle size (1.6 mm) and 250 ml of n-hexane were added, and the mixture was stirred at 68 ° C. for 1 hour. Then, the metallic magnesium was taken out and dried at 65 ° C. under reduced pressure to obtain preactivated metallic magnesium.

Next, 140 ml of n-butyl ether and an n-butyl ether solution of n-butylmagnesium chloride (1.75 mol / l) were added to 0.5 g of the metallic magnesium.
The resulting suspension was kept at 55 ° C., and a solution of 38.5 ml of n-butyl chloride dissolved in 50 ml of n-butyl ether was added dropwise over 50 minutes. After conducting the reaction at 70 ° C. for 4 hours with stirring, the reaction solution was kept at 25 ° C.

Next, HC (OC) was added to the reaction solution.
It was added dropwise ₂ H _{5) 3 55.7ml} over one hour. After the completion of the dropwise addition, the reaction was carried out at 60 ° C. for 15 minutes. The solid produced by the reaction was washed six times with 300 ml each of n-hexane and dried under reduced pressure at room temperature for 1 hour. Was recovered.

Under a nitrogen gas atmosphere, 6.3 g of a magnesium-containing solid and 50 ml of n-heptane were put into a 300 ml reaction vessel equipped with a reflux condenser, a stirrer, and a dropping funnel to form a suspension. , 2,2,2-trichloroethanol 20ml (0.02mmol) and n-heptane 11m
of mixed solution was added dropwise from a dropping funnel over 30 minutes, and further stirred at 80 ° C. for 1 hour. The obtained solid was separated by filtration, washed four times with 100 ml each of n-hexane at room temperature, and twice with 100 ml each of toluene to obtain a solid component.

To the above solid components, 40 ml of toluene was added.
Further, titanium tetrachloride was added so that the volume ratio of titanium tetrachloride / toluene became 3/2, and the temperature was raised to 90 ° C. Under stirring, a mixed solution of 2 ml of di-n-butyl phthalate and 5 ml of toluene was added dropwise over 5 minutes, followed by stirring at 120 ° C. for 2 hours.
The obtained solid substance was separated by filtration at 90 ° C., and toluene 100 m each.
2 times at 90 ° C. Further, titanium tetrachloride was added so that the volume ratio of titanium tetrachloride / toluene was 3/2, and the mixture was stirred at 120 ° C. for 2 hours. The obtained solid substance is 110
The mixture was filtered at ℃ and washed seven times with 100 ml of n-hexane at room temperature seven times to obtain 15.5 g of the component A. In a nitrogen gas atmosphere, 2.5 g of the above-obtained component A1 and 100 ml of n-hexane were put in a 200-ml reactor which had been replaced with prepolymerized nitrogen and dried sufficiently, and cooled to 0 ° C. with stirring. . Next, 5 mmol of triethylaluminum and 1 mmol of isopropoxycyclopentyldimethoxysilane were added under stirring. After continuing stirring at the same temperature for 10 minutes, propylene gas was continuously supplied. When the consumption of propylene reached 7.5 g, the supply of propylene gas was stopped. Thereafter, after stirring was continued for 10 minutes, the stirring was stopped, and washing by decantation was performed 5 times with 80 ml of hexane to obtain a slurry of the polymerization catalyst component A1 '. Main polymerization In a 1.5-liter autoclave sufficiently purged with nitrogen, the polymerization catalyst component A obtained above was placed under a nitrogen atmosphere.
1 ′ 29.4 mg, 2 ml of n-heptane solution of triethylaluminum (0.2 mol / l) and 2 ml of n-heptane solution of isopropoxycyclopentadienyldimethoxysilane (0.04 mol / l) were mixed and kept for 5 minutes. I put it. Next, 11 liters of hydrogen gas and 1 liter of liquid propylene were injected under pressure as a molecular weight regulator, and polymerization was carried out for 1 hour at an internal temperature of 70 ° C. in the autoclave. After the completion of the polymerization, hydrogen and unreacted propylene were purged, and the polymer in the autoclave was taken out. 242.9 g of polymer were obtained with an MFR of 155.3
g / 10 minutes. The measured HI of this polymer was 94.9.

The spherulite nucleation density I, spherulite growth rate G and spherulite nucleation temperature CT of the obtained polymer were measured, and the flexural modulus was also measured. Table 3 shows the results.

Example 2 A polypropylene was obtained in the same manner as in Example 1 except that the amounts of the silane compound and the molecular weight regulator (hydrogen) used in the prepolymerization and the main polymerization were changed as shown in Table 1. The obtained polypropylene was measured for MFR, HI, spherulite nucleation density I, spherulite growth rate G and flexural modulus. Table 3 shows the results.

Comparative Example 1 A polypropylene was obtained in the same manner as in Example 1 except that the amounts of the silane compound and the molecular weight regulator (hydrogen) used in the prepolymerization and the main polymerization were changed as shown in Table 1. The obtained polypropylene was measured for MFR, HI, spherulite nucleation density I, spherulite growth rate G, spherulite nucleation temperature CT and flexural modulus. Table 3 shows the results.

[0036]

[Table 1]

Example 3 Preparation of Polymerization Catalyst Component A2 A 200 ml flask equipped with a dropping funnel and a stirrer was purged with nitrogen. In this flask, silicon oxide (D
AVISON Co., Ltd., trade name: G-952) was calcined in a nitrogen stream at 200 ° C. for 2 hours and further at 700 ° C. for 5 hours, and 5 g and n-heptane 40 ml were added. further,
n-butylethylmagnesium (hereinafter referred to as BEM)
20 ml of a 20% n-heptane solution (manufactured by Texas Alkyls, trade name: MAGARA BEM) was added, and the mixture was stirred at 90 ° C. for 1 hour.

After the obtained suspension was cooled to 0 ° C., a solution obtained by dissolving 11.2 g of tetraethoxysilane in 20 ml of n-heptane was dropped from the dropping funnel over 30 minutes. After dropping, the temperature was raised to 50 ° C over 2 hours,
Stirring was continued for hours. After completion of the reaction, the supernatant was removed by decantation, and the resulting solid was washed with 60 ml of n-heptane at room temperature, and the supernatant was removed by decantation. This washing treatment with n-heptane was further performed four times.

To the obtained solid, 50 ml of n-heptane was added to form a suspension, and 2,2,2-trichloroethanol was added to the suspension.
A solution of 0 g in 10 ml of n-heptane was added dropwise from a dropping funnel at 25 ° C. over 15 minutes. After completion of the dropwise addition, stirring was continued at 25 ° C. for 30 minutes. After the completion of the reaction, washing was performed twice at room temperature with 60 ml of n-heptane and three times with 60 ml of toluene. When the obtained solid (solid component I) was analyzed, SiO ₂ 36.6%, Mg 5.1
% And Cl 38.5%.

The solid component I obtained above was added to n-heptane
10 ml and 40 ml of titanium tetrachloride were added, the temperature was raised to 90 ° C., and di-n-butyl phthalate was dissolved in 5 ml of n-heptane.
6 g was added over 5 minutes. Thereafter, the temperature was raised to 115 ° C., and the reaction was carried out for 2 hours. After the temperature was lowered to 90 ° C., the supernatant was removed by decantation, and the mixture was washed twice with 70 ml of n-heptane. Furthermore, n-heptane 15 ml and titanium tetrachloride 40
Then, the mixture was reacted at 115 ° C. for 2 hours. After the reaction,
The obtained solid component was washed eight times at room temperature with 60 ml of n-hexane. Next, drying was carried out at room temperature under reduced pressure for 1 hour to obtain 8.3 g of a catalyst component (component A2). This component A2 contained silicon oxide, Cl and di-n-butyl phthalate in addition to 3.1% of Ti. Under a nitrogen gas atmosphere, 2.5 g of the component A obtained above and 100 ml of n-hexane were put in a 200 ml reactor which had been sufficiently dried by replacing with prepolymerized nitrogen, and cooled to 0 ° C. with stirring. . Next, 5 mmol of triethylaluminum and 1 mmol of sec-butoxycyclopentyldimethoxysilane were added under stirring. After continuing stirring at the same temperature for 10 minutes, propylene gas was continuously supplied. When the consumption of propylene reached 7.5 g, the supply of propylene gas was stopped. Then, after stirring was continued for 10 minutes, the stirring was stopped, and washing by decantation was performed 5 times with 80 ml of hexane to obtain a slurry of the polymerization catalyst component A2 '. Main polymerization In a 1.5-liter autoclave sufficiently purged with nitrogen, the polymerization catalyst component A obtained above was placed under a nitrogen atmosphere.
2 ′ 62.3 mg, 2 ml of n-heptane solution of triethylaluminum (0.2 mol / l) and 2 ml of n-heptane solution of t-butoxycyclopentadienyldimethoxysilane (0.04 mol / l) were mixed and kept for 5 minutes. Was put. Next, 0.5 liter of hydrogen gas as a molecular weight regulator and 1 liter of liquid propylene were injected under pressure, and polymerization was carried out for 1 hour at an internal temperature of the autoclave of 70 ° C. After the completion of the polymerization, hydrogen and unreacted propylene were purged, and the polymer in the autoclave was taken out. 232.1 g of polymer were obtained with an MFR of 1.5 g /
10 minutes. When the HI of this polymer was measured,
98.5.

The spherulite nucleation density I, spherulite growth rate G and spherulite nucleation temperature CT of the obtained polymer were measured, and the flexural modulus was measured. Table 3 shows the results.

Comparative Example 2 A polypropylene was obtained in the same manner as in Example 3 except that the amounts of the silane compound and the molecular weight regulator (hydrogen) used in the prepolymerization and the main polymerization were changed as shown in Table 2. The obtained polypropylene was measured for MFR, HI, spherulite nucleation density I, spherulite growth rate G, spherulite nucleation temperature CT and flexural modulus. Table 3 shows the results.

[0043]

[Table 2]

[0044]

[Table 3]

[0045]

The crystalline polypropylene of the present invention has a good balance of moldability and rigidity and can be used for a wide range of applications. In particular, it is suitable for injection molding applications.

[Brief description of the drawings]

FIG. 1 shows an apparatus 2 used for obtaining a spherulite nucleus generation density I and a spherulite growth rate G in an example, and an apparatus 1 inserted therein.

[Explanation of symbols]

 a device 1 b device 2 c cover glass d sample e heater

Claims (1)

[Claims] (1) The melt flow rate MFR is 0.5
(2) the weight ratio HI of the residue to the whole polymer after extraction with boiling n-heptane for 6 hours in a modified Soxhlet extractor satisfies 90 <HI;
And (3) the spherulite nucleation density I and the spherulite growth rate G determined during the spherulite growth process during the isothermal crystallization at 135 ° C., and the spherulite nucleation temperature CT (° C.) determined by the differential scanning calorimetry. ) Is expressed by the following equation (i): A = 0.8209 × log (I) + 9.481 × log (G) + 0.1616 × (CT) -23.15 (i) (where I is G is represented by the number of spherulite nuclei per 1 mm ³ , and G is an increase rate (μm) of spherulite radius (μm) per minute.
m / min) and CT is expressed as the temperature (° C.) at which crystallization starts in differential scanning calorimetry), wherein the value of A is 5.0 or more. polypropylene.