JPH0948820A - Molded polypropylene article - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain the subject molded article having excellent hightemperature characteristics such as rigidity at a high temperature and excellent toughness and chemical stability and useful as various injection molded articles for industrial use, etc., by using a catalyst composed of a chiral transition metal compound and an aluminoxane. SOLUTION: The objective polypropylene having an isotactic pentad fraction of 0.950-0.955, a syndiotactic pentad fraction of 0-0.01, a bontent of hetero-bond caused by 2, 1 and 3, 1 insertion reaction of 0-0.3mol%, a weight-average molecular weight of 50.000-1,000,000 and a weight-average molecular weight to number- average molecular weight ratio of 1.5-3.8 and free from terminal double bond is produced by polymerizing propylene in the presence of hydrogen using a catalyst composed of a chiral transition metal compound of formula [(C5 H4-m R<1> m ) and (C5 H4-n R<2> n ) are each a substituted cyclopentadienyl; (m) and (n) are each 1-3; R<1> and R<2> are each a 1-20C hydrocarbon group, an Si-containing hydrocarbon group, etc.; Q is a bivalent hydrocarbon group, unsubstituted silylene group or hydrocarbon-substituted silylene group crosslinking the (C5 H4-m R<1> m ) and (C5 H4-n R<2> n ); M is titanium, zirconium or hafnium; X and Y are each H, a halogen or a hydrocarbon group[ and an aluminoxane.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a polypropylene molded article. More specifically, it is composed of polypropylene having high stereoregularity and narrow molecular weight distribution, which is obtained by polymerizing propylene using a metallocene catalyst and has excellent high temperature characteristics such as rigidity at high temperature, toughness, and chemical stability. It relates to a polypropylene molded product.

[0002]

2. Description of the Related Art Crystalline polypropylene has mechanical properties,
It is widely used in various molding fields because it has excellent chemical resistance and is very useful in balance with economic efficiency. However, there is a limit to the performance of known molded articles made of ordinary polypropylene, and the improvement of the performance of polypropylene molded articles, especially the improvement of heat resistance characteristics such as rigidity at high temperatures, and high toughness are strongly demanded for the solution. There is.

On the other hand, in recent years, it has been known that propylene is polymerized using a catalyst obtained by combining a metallocene and an aluminoxane different from the conventional catalyst system to obtain stereoregular polypropylene having a narrow molecular weight distribution.

For example, propylene is polymerized by using a catalyst composed of a silicon-bridged metallocene having a specific structure and an aluminoxane to obtain highly stereoregular polypropylene having a narrow molecular weight distribution (Japanese Patent Laid-Open No. 3-12406).
JP-A-3-12407, CHEMISTRY LETTERS, pp.
1853-1856, 1989). The polypropylene obtained by this method has a narrow molecular weight distribution, high stereoregularity, and has a higher melting point and higher rigidity than polypropylene obtained from conventional metallocene catalysts. Is carried out in the absence of hydrogen, a double bond is present at one end of the polymer, and chemical stability may be impaired depending on the conditions of use, and improvement has been desired. Further, when formed into a molded product, further improvement in heat resistance and high toughness have been desired.

[0005]

As described above, since the narrow molecular weight polypropylene obtained by the known method has a double bond at one end, it has problems in heat resistance and toughness when formed into a molded product. was there.

The inventors of the present invention have solved the problems of the above-mentioned known invention, and have conducted earnest studies on the invention of a polypropylene molded product made of polypropylene having a narrow molecular weight distribution and a high stereoregularity and having no double bond. As a result, a narrow molecular weight distribution, which does not have a double bond and hardly has a heterologous bond, which is obtained only under a specific polymerization condition, is obtained even though a catalyst similar to the catalyst used in the above-mentioned known invention is used. When a polypropylene having an extremely high stereoregularity was discovered and a polypropylene having the specific structure was used as a molded product, it had extremely high temperature characteristics and high toughness.
Further, the inventors of the present invention arrived at the present invention knowing that the moldability was also good.

As is apparent from the above description, the object of the present invention is to obtain a polymer obtained by polymerizing propylene using a metallocene catalyst, which is excellent in high temperature characteristics such as rigidity at high temperature, toughness, and chemical stability. It is intended to provide a polypropylene molded article made of polypropylene having high stereoregularity and a narrow molecular weight distribution.

[0008]

The present invention has the following means (1). (1) General formula Q (C ₅ H _4-m R ¹ _m ) (C ₅ H _4-n R ² _n ) MX
A chiral transition metal compound represented by Y, [wherein (C ₅
H _4-m R ¹ _m ) and (C ₅ H _4-n R ² _n ) represent a substituted cyclopentadienyl group, and m and n are integers of 1 to 3. R ¹ and R ² are a hydrocarbon group having 1 to 20 carbon atoms, a silicon-containing hydrocarbon group, or one which may be bonded to two carbon atoms on the cyclopentadienyl ring and substituted with a hydrocarbon. The hydrocarbon groups forming the above hydrocarbon ring may be the same or different. Q is (C ₅ H
_4-m R ¹ _m ) and (C ₅ H _4-n R ² _n ) are both divalent hydrocarbon groups, unsubstituted silylene groups or hydrocarbon-substituted silylene groups. M represents a transition metal such as titanium, zirconium or hafnium, and X and Y may be the same or different and each represents hydrogen, halogen or a hydrocarbon group. ] And aluminoxane were used to polymerize propylene in the presence of hydrogen,
Isotactic pentad fraction (mmmm) is 0.9
50 to 0.995, the syndiotactic pentad fraction (rrrr) is 0 to 0.01, and the hetero bond resulting from the 2,1 insertion reaction and the 1,3 insertion reaction is 0 to 0.3 mo.
1%, no terminal double bond is present, weight average molecular weight (Mw) is 50,000 to 1,000,000, and ratio of weight average molecular weight (Mw) to number average molecular weight (Mn) (Mw / Mn) A polypropylene molded article consisting essentially of polypropylene having a ratio of 1.5 to 3.8.

The structure of the present invention will be described in detail below. Among the requirements required for the polypropylene used in the molded article of the present invention ,,, and are calculated based on the measurement result of ¹³ C nuclear magnetic resonance spectrum according to the following method. That is, it is determined by using a mixed solution of o-dichlorobenzene / benzene bromide = 8/2 weight ratio having a polymer concentration of 20 weight% and measuring at 67.20 MHz and 130 ° C. As a measuring device, for example, a JEOL-GX270 NMR measuring device manufactured by JEOL Ltd. is used.

The isotactic pentad fraction (mmmm) and the syndiotactic pentad fraction (rrrr) in the present invention mean A. Zambelli.
Isotactic and syndiotactic fractions in pentad units in the polypropylene molecular chain as determined by ¹³ C nuclear magnetic resonance spectroscopy proposed by et al. (Macromolecules 6, 925 (1973)). See also book ¹³
A method for determining the attribution of peaks in the measurement of C nuclear magnetic resonance spectra was proposed by A. Zambelli and others (Macr
omolecules 8, 687 (1975)).

Isotactic pentad fraction (mmmm) required for polypropylene used in the molded article of the present invention
As described above, is the abundance ratio of propylene monomer units in which five meso-bonds are continuously formed among all propylene monomer units in the polypropylene molecule. Therefore, the higher the isotactic pentad fraction (mmmm), the higher the isotacticity. In the polypropylene used for the molded article of the present invention, the isotactic pentad fraction (mmmm) is 0.950 to 0.99.
5, preferably 0.955 to 0.995, and particularly preferably 0.960 to 0.995.

The syndiotactic pentad fraction (rrr) required for the polypropylene used in the molded article of the present invention.
r) is the abundance ratio of propylene monomer units having five consecutive racemic bonds among all the propylene monomer units in the polypropylene molecule. Therefore, the lower the syndiotactic pentad fraction (rrrr), the lower the syndiotactic property. In the polypropylene of the present invention, the syndiotactic pentad fraction (rrrr) is 0 to 0.01, preferably 0.
It is 0.007, and particularly preferably 0 to 0.004.

2,1 insertion reaction and 1, in the present invention
What is a heterozygous bond caused by a 3-insertion reaction? (T. Tsutsui)
2,1 insertion reaction and 1,3 in polypropylene molecular chains measured by ¹³ C nuclear magnetic resonance spectroscopy based on the method proposed by K. et al. (POLYMER, 30 , 1350 (1989))
It is the ratio of heterologous bonds due to the insertion reaction.

Requirement of polypropylene used in the molded article of the present invention The heterogeneous bond resulting from the 2,1 insertion reaction and the 1,3 insertion reaction is 0 to 0.3 mol%, preferably 0.
~ 0.2 mol%, particularly preferably 0-0.1 mol%
It is. It should be noted that, while propylene polymerization, which proceeds with a known ordinary titanium-based catalyst, proceeds mostly with 1,2 insertion reaction, whereas known metallocene catalyst has a certain degree of 2,1 insertion reaction and 1,3 insertion reaction. It is known that a certain amount of heterogeneous bonds are present in the obtained polypropylene.

Based on the above requirements, the polypropylene used in the molded article of the present invention has extremely high isotacticity, which is composed of an extremely highly controlled meso bond chain with almost no heterogeneous bond or racemic bond chain. It can be said that it shows.

The measurement of the terminal double bond in the present invention was shown by T. Hayashi et al. (POLYMER, 30 ,
2 at the end of the polypropylene molecule measured by ¹³ C nuclear magnetic resonance spectroscopy based on the method of 1717 (1989)).
It is the existence ratio of heavy bonds.

The requirement for the polypropylene used in the moldings of the invention is the absence of terminal double bonds. As described above, when a double bond is present at the end of the polypropylene molecule, the chemical stability of the polypropylene may be impaired due to the double bond participating in the reaction depending on the conditions of use, and as a result, The original characteristics of polypropylene may not be exhibited.

Further, among the requirements required for polypropylene used for the molded article of the present invention, the weight average molecular weight (Mw) and the ratio of the weight average molecular weight (Mw) to the number average molecular weight (Mn) (Mw / Mn). Is calculated based on the measurement result of gel permeation chromatography (GPC) according to the following method. That is, an o-dichlorobenzene solution having a polymer concentration of 0.05% by weight was used, and the column was a mixed polystyrene gel column (for example, PSKgel GMH6- manufactured by Tosoh Corporation).
HT) and measured at 135 ° C. As a measuring device, for example, G manufactured by Waters
PC-150C is used.

The weight average molecular weight (Mw), which is a requirement for the polypropylene used in the molded article of the present invention, is from 50,000 to.
1,000,000, preferably 100,000
１，1,000,000.

The ratio (Mw / Mn) of the weight average molecular weight (Mw) to the number average molecular weight (Mn), which is a requirement of the polypropylene used in the molded article of the present invention, is 1.5 to 3.8, preferably 1. 5 to 3.5. The ratio (Mw / Mn) of the weight average molecular weight (Mw) to the number average molecular weight (Mn) is a measure of the molecular weight distribution, and the ratio (Mw)
When / Mn) is large, the molecular weight distribution is wide, and when it is small, the molecular weight distribution is narrow.

The essential requirements of the polypropylene used in the molded article of the present invention are the above-mentioned 6 requirements, but due to these structural characteristics, particularly the requirements 1 to 3,
The melting point of the polypropylene is 160 to 168 ° C., depending on the structural conditions, 162 to 168 ° C., and further 163 to 168 ° C.
Is shown.

The melting point here is that polypropylene is heated from room temperature to 230 ° C. under a temperature rising condition of 30 ° C./min using a DSC7 type differential scanning calorimeter manufactured by Perkin-Elmer Co., Ltd., and kept at the same temperature for 10 minutes. After holding, at -20 ° C / min-2
After cooling to 0 ° C and holding at the same temperature for 10 minutes,
The temperature at which the peak at the time of melting under the temperature increasing condition of ° C./min was defined as the melting point.

The polypropylene used in the above-mentioned molded article of the present invention is produced by using a specific metallocene catalyst.

Next, a method for producing the polypropylene used in the molded article of the present invention using a specific metallocene catalyst will be described. The metallocene catalyst used in the method for producing polypropylene used for the molded article of the present invention is a catalyst obtained by using metallocene as a transition metal compound and combining this with aluminoxane.

The metallocene usable above is represented by the general formula Q (C ₅ H _4-m R ¹ _m ) (C ₅ H _4-n R ² _n ) MXY.
A chiral transition metal compound represented by the formula: [wherein (C ₅ H
_4-m R ¹ _m ) and (C ₅ H _4-n R ² _n ) represent a substituted cyclopentadienyl group, and m and n are integers of 1 to 3.
R ¹ and R ² are a hydrocarbon group having 1 to 20 carbon atoms, a silicon-containing hydrocarbon group, or one which may be bonded to two carbon atoms on the cyclopentadienyl ring and substituted with a hydrocarbon. The hydrocarbon groups forming the above hydrocarbon ring may be the same or different. Q is (C ₅ H _4-m R
¹ _m ) and (C ₅ H _4-n R ² _n ) are both divalent hydrocarbon groups, unsubstituted silylene groups or hydrocarbon-substituted silylene groups. M represents a transition metal such as titanium, zirconium or hafnium, and X and Y may be the same or different and each represents hydrogen, halogen or a hydrocarbon group. ].

More preferably, in the above general formula, R
¹ and R ² are alkyl groups having 1 to 20 carbon atoms, which may be the same or different, Q is a dialkylsilylene group, M is a transition metal which is zirconium or hafnium, and X and Y are the same or different. A chiral transition metal compound, which may be different and is a halogen or a hydrocarbon group, is used.

Such metallocenes are specifically ra
c-Dimethylsilylenebis (2-methyl-4,5,6,6
7-tetrahydroindenyl) zirconium dichloride, rac-dimethylsilylenebis (2-methyl-4,
5,6,7-Tetrahydroindenyl) zirconium dimethyl, rac-ethylenebis (2-methyl-4,5,5
6,7-Tetrahydroindenyl) hafnium dichloride, rac-dimethylsilylenebis (2-methyl-4)
-Phenylindenyl) zirconium dichloride, r
ac-dimethylsilylenebis (2-methyl-4-phenylindenyl) zirconium dimethyl, rac-dimethylsilylenebis (2-methyl-4-phenylindenyl) hafnium dichloride, dimethylsilylene (2,
4-dimethylcyclopentadienyl) (3 ′, 5′-dimethylcyclopentadienyl) titanium dichloride, dimethylsilylene (2,4-dimethylcyclopentadienyl) (3 ′, 5′-dimethylcyclopentadienyl) Zirconium dichloride, dimethylsilylene (2,4-dimethylcyclopentadienyl) (3 ',
5'-dimethylcyclopentadienyl) zirconium dimethyl, dimethylsilylene (2,4-dimethylcyclopentadienyl) (3 ', 5'-dimethylcyclopentadienyl) hafnium dichloride, dimethylsilylene (2,4-dimethylcyclo) Pentadienyl) (3 ',
5′-dimethylcyclopentadienyl) hafnium dimethyl, dimethylsilylene (2,3,5-trimethylcyclopentadienyl) (2 ′, 4 ′, 5′-trimethylcyclopentadienyl) titanium dichloride, dimethylsilylene (2 , 3,5-Trimethylcyclopentadienyl) (2 ′, 4 ′, 5′-trimethylcyclopentadienyl) zirconium dichloride, dimethylsilylene (2,3,5-trimethylcyclopentadienyl)
(2 ′, 4 ′, 5′-trimethylcyclopentadienyl) zirconium dimethyl, dimethylsilylene (2,
3,5-trimethylcyclopentadienyl) (2 ′,
4 ', 5'-trimethylcyclopentadienyl) hafnium dichloride, dimethylsilylene (2,3,5-trimethylcyclopentadienyl) (2', 4 ', 5'-
Trimethylcyclopentadienyl) hafnium dimethyl.

Of these metallocenes, dimethylsilylene (2,4-dimethylcyclopentadienyl) (3 ', 5'-dimethylcyclopentadienyl) zirconium dichloride and dimethylsilylene (2,4-dimethyl) are particularly preferred. Cyclopentadienyl) (3 ',
5'-dimethylcyclopentadienyl) zirconium dimethyl, dimethylsilylene (2,4-dimethylcyclopentadienyl) (3 ', 5'-dimethylcyclopentadienyl) hafnium dichloride, dimethylsilylene (2,4-dimethylcyclo) Pentadienyl) (3 ',
5′-dimethylcyclopentadienyl) hafnium dimethyl, dimethylsilylene (2,3,5-trimethylcyclopentadienyl) (2 ′, 4 ′, 5′-trimethylcyclopentadienyl) zirconium dichloride, dimethylsilylene (2 , 3,5-Trimethylcyclopentadienyl) (2 ', 4', 5'-trimethylcyclopentadienyl) zirconium dimethyl, dimethylsilylene (2,3,5-trimethylcyclopentadienyl)
(2 ', 4', 5'-trimethylcyclopentadienyl) hafnium dichloride, dimethylsilylene (2,
3,5-trimethylcyclopentadienyl) (2 ′,
4 ', 5'-trimethylcyclopentadienyl) hafnium dimethyl.

Although a meso metallocene having a non-chiral structure may be formed as a by-product during the synthesis of these chiral metallocenes, in actual use, it is not necessary that all of the chiral metallocenes be chiral metallocenes and the meso form is mixed. It does not matter if you However, when using a mixture with the meso form, it depends on the mixing amount of the meso form and the propylene polymerization activity,
In some cases, it may be necessary to remove the atactic polypropylene polymerized from the meso form by a known method such as solvent extraction so that the obtained polypropylene satisfies the above-mentioned essential requirements.

Further, these chiral metallocenes can be used as they are as a catalyst by combining them with aluminoxane, but they can also be used by being carried on a fine particle carrier. As such a fine particle carrier, an inorganic or organic compound having a particle diameter of 5 to 300 μm,
Preferably, a granular or spherical fine particle solid having a particle size of 10 to 200 μm is used.

Among these, as the inorganic compound used for the carrier, SiO ₂ , Al ₂ O ₃ , MgO, TiO ₂ , ZnO or the like or a mixture thereof, for example, SiO ₂ -Al.
₂ O ₃ , SiO ₂ -MgO, SiO ₂ -TiO ₂ , SiO _2-
Al ₂ O ₃ -MgO and the like. In these, S
Those containing iO ₂ or Al ₂ O ₃ as a main component are preferred.

The organic compounds used for the carrier include ethylene, propylene, 1-butene and 4-methyl-
Examples thereof include polymers or copolymers of C2-C12 α-olefins such as 1-pentene, and further, styrene polymers or copolymers.

The aluminoxane combined with metallocene as a catalyst component used in the production of polypropylene used for the molded article of the present invention is an organoaluminum compound represented by the following general formula [1] or [2].

Embedded image

Embedded image Here, R ³ is a hydrocarbon group having 1 to 6 carbon atoms, preferably 1 to 4 carbon atoms, specifically, methyl group, ethyl group, propyl group, butyl group, isobutyl group, pentyl group, hexyl group, etc. Alkyl group, allyl group, 2-methylallyl group,
Examples include an alkenyl group such as a propenyl group, an isopropenyl group, a 2-methyl-1-propenyl group, a butenyl group, a cycloalkyl group such as a cyclopropyl group, a cyclobutyl group, a cyclopentyl group, and a cyclohexyl group, and an aryl group. Among these, an alkyl group is particularly preferred, and each R ³ may be the same or different.

Further, p is an integer of 4 to 30, preferably 6 to 30, and particularly preferably 8 to 30.

These aluminoxanes can be used not only in one kind but also in a combination of two or more kinds, and are used in combination with an alkylaluminum compound such as trimethylaluminum, triethylaluminum, triisobutylaluminum and dimethylaluminum chloride. It is also possible.

The above aluminoxane can be prepared under various known conditions. Specifically, the following method can be exemplified. (1) A method in which a trialkylaluminum is directly reacted with water using an organic solvent such as toluene or ether. (2) salts having trialkylaluminum and water of crystallization,
For example, a method of reacting with copper sulfate hydrate and aluminum sulfate hydrate. (3) A method of reacting trialkylaluminum with moisture impregnated in silica gel or the like. (4) Mixing trimethylaluminum and triisobutylaluminum, toluene,
A method of directly reacting with water using an organic solvent such as ether. (5) A method in which trimethylaluminum and triisobutylaluminum are mixed and reacted with salts having water of crystallization, such as copper sulfate hydrate and aluminum sulfate hydrate. (6) A method in which silica gel or the like is impregnated with water, triisobutylaluminum is reacted, and then trimethylaluminum is further reacted.

The catalyst used in the production of polypropylene used in the molded article of the present invention is a catalyst obtained by combining the above metallocene and aluminoxane. The amount of each catalyst component used is such that the aluminum atom in the aluminoxane is 10 to 1 mol of the transition metal atom in the metallocene.
100,000 mol, preferably 50-50,000
The molar amount is particularly preferably 100 to 30,000.

By using the catalyst thus combined to polymerize propylene in the presence of hydrogen, polypropylene to be used in the molded article of the present invention can be obtained. As a propylene polymerization method, a known propylene polymerization process can be used. Yes, butane, pentane, hexane, heptane, isooctane and other aliphatic hydrocarbons, cyclopentane, cyclohexane, methylcyclohexane and other alicyclic hydrocarbons, toluene, xylene, ethylbenzene and other aromatic hydrocarbons, and gasoline fractions Slurry polymerization method that polymerizes propylene in an inert solvent such as hydrogenated diesel oil fraction, bulk polymerization that uses propylene itself as a solvent, and gas phase polymerization method that performs propylene polymerization in the gas phase can be used. is there.

In the polymerization of propylene, the catalyst described above may be a mixture of both metallocene and aluminoxane components previously mixed in an inert solvent, and the mixture may be supplied to the polymerization reaction system, or the metallocene and the aluminoxane may be added to the polymerization reaction system. They may be supplied separately. Furthermore, prior to the main polymerization of propylene, a small amount of α-olefin, specifically, 1 mol of transition metal in metallocene, was added to a catalyst in which a metallocene and an aluminoxane were combined in an inert solvent.
It is also effective to carry out the main polymerization of propylene after the polymerization reaction of the α-olefin of about 1 g to 10 kg and as a pre-activated catalyst is effective in obtaining the final polypropylene in a good particle shape. Within the range of.

As the α-olefin that can be used for the pre-activation, an α-olefin having 2 to 12 carbon atoms is preferably used, and specifically, ethylene, propylene, butene, pentene, hexene, octene, 4- Methyl-1-
Pentene, etc., particularly ethylene, propylene, 4
-Methyl-1-pentene is preferably used.

The thus prepared catalyst for use in the present invention or the pre-activated catalyst is used for the polymerization of propylene by the above-mentioned polymerization method. The polymerization conditions in the propylene polymerization are generally known Ziegler system. Polymerization conditions similar to those for propylene polymerization with a catalyst are adopted. That is, the polymerization temperature is −50 to 150 ° C., preferably −10.
At a temperature of ~ 100 ° C, the polymerization pressure is atmospheric pressure ~ 7 MPa,
The pressure is preferably 0.2 MPa to 5 MPa, and is usually carried out in the presence of hydrogen for about 1 minute to 20 hours. The amount of hydrogen was 0. 1 in terms of hydrogen partial pressure in the gas phase in the polymerization vessel.
A suitable amount is 1 kPa to 5 MPa, preferably 1 kPa to 3 MPa.

After completion of the propylene polymerization, the polypropylene according to the present invention can be obtained after the known post-treatment steps such as catalyst deactivation treatment step, catalyst residue removal step and drying step, if necessary. Is the required 6 mentioned above
Must have requirements. Unless these requirements are satisfied, the object of the present invention cannot be achieved.

That is, if the above-mentioned metallocene is used and propylene is polymerized under the above-mentioned polymerization conditions, the polypropylene used for the molded article of the present invention is not always obtained, and depending on the kind of metallocene, it may be optimum. It is necessary to select proper polymerization conditions. The optimum polymerization condition is often selected from a relatively low polymerization temperature within the above-mentioned polymerization condition range.

The polypropylene used in the molded article of the present invention thus obtained had a narrow molecular weight distribution and a high melting point.
High stereoregular polypropylene, various additives such as antioxidants, ultraviolet absorbers, antistatic agents, nucleating agents, lubricants, flame retardants, antiblocking agents, coloring agents, inorganic or organic fillers as necessary. Ingredients and further various synthetic resins are blended and kept in powder state or after being melt-kneaded by heating for 20 seconds to 30 minutes at 190 to 350 ° C for about 20 seconds to 30 minutes, further pelletized At that time, it is used as a molding material.

Molding is carried out by various known polypropylene molding methods, such as injection molding, extrusion molding, foam molding, blow molding, and various industrial injection molded parts.
Various molded articles such as various containers, non-stretched films, uniaxially stretched films, biaxially stretched films, sheets, pipes, fibers and the like can be obtained.

The molded article of the present invention thus obtained may optionally contain an antioxidant, an ultraviolet absorber, an antistatic agent, a nucleating agent, a lubricant, a flame retardant, an antiblocking agent, a colorant, as described above. Various additives such as inorganic or organic fillers and further various synthetic resins may be blended,
Substantially, it is made of polypropylene having a specific structure obtained by the specific method used in the present invention.
The term "consisting essentially of" is used in the sense that it includes the above-mentioned substances that are added and blended as needed, and it is contained in a molded article at least 50% by weight or more, preferably 70% by weight.
As described above, it is meant that the polypropylene used in the present invention satisfying the above-mentioned essential requirements at a ratio of 80% by weight or more is more preferable.

[0047]

EXAMPLES Next, the present invention will be specifically described with reference to examples. Definitions of terms used in Examples and Comparative Examples and measurement methods are as follows. (1) Isotactic pentad fraction: [mmm
m] was measured by the method described above. (2) Fraction of syndiotactic pentad: [rrr
r] was measured by the method described above. (3) Heterologous binding amount: (IV), measured by the method described above. (4) Weight average molecular weight: (Mw), measured by the method described above. (5) Number average molecular weight: (Mn), measured by the method described above. (6) Melting point: (Tm), which was measured by the method described above.
(Unit: ℃) (7) High temperature rigidity: After leaving the JIS type test piece in a room with relative humidity of 50% and room temperature of 23 ℃ for 72 hours,
According to JISK7203, the bending elastic modulus was measured at a measurement temperature of 80 ° C. (Unit: MPa) (8) Toughness: In the uniaxial tensile test of the evaluation test piece, it is considered that the material strength up to the fracture after the yield point represents the toughness, and the (breaking point strength-yield point strength) is a scale of the toughness. And
That is, a test piece of 50 mm in length and 6 mm in width punched out from a compression-molded sheet having a thickness of 0.5 mm was measured with a Toyo Seiki strograph at a displacement rate of 10 mm at 40 ° C.
The test piece was stretched in the machine direction at a speed of 1 / min, and the yield strength at that time was Sy (unit: MPa). Next, after cutting the necked portion of the tensile test piece, whose neck strength has been measured, with a pair of scissors, the central portion of the test piece is displaced again at 40 ° C. at a displacement rate of 1
The test piece was stretched in the longitudinal direction at 0 mm / min, and the strength at which the test piece broke was defined as the breaking strength Sb (unit: MPa). Here, (Sb-Sy) was used as a measure of toughness. (Unit: MP
The higher value of a) indicates that the toughness is higher. (9) Film glossiness: The glossiness of the cooling surface and the outside air surface was measured according to ASTM D523. (Unit:%) The higher the value, the higher the glossiness. (10) Film Young's modulus: MD (longitudinal direction) / TD (horizontal direction) tensile strength was measured according to ASTM D882. (Unit: N / mm ² ) The higher the Young's modulus, the higher the rigidity. (11) Heat shrinkage rate: A 100 mm × 10 mm film was cut in each of MD (longitudinal direction) and TD (horizontal direction) measurement directions, and the film was cut at 140 ° C. silicon oil (Toray Silicone Co., SH-200). After heating in a bath for 10 minutes, each length was measured, and the heat shrinkage ratio in each measurement direction was calculated from the following formula: shrinkage ratio = 100 × (length before heating−length after heating) / length before heating. . (Unit:%) The smaller the shrinkage ratio, the less the shrinkage due to heating.

Example 1 (1) Production of polypropylene After a stainless steel polymerization vessel equipped with a stirrer and having an internal volume of 100 dm ³ and equipped with a stirrer was replaced with nitrogen gas, 50 dm of n-hexane and toluene of methylaluminoxane were placed in the polymerization vessel. Solution (product of Tosoh Akzo, trade name: MMAO, concentration:
2 mol / dm ³ ) is 7.6 mol in terms of Al atom, and chiral dimethylsilylene (2,3,5) as metallocene.
-Trimethylcyclopentadienyl) (2 ', 4',
5'-trimethylcyclopentadienyl) hafnium dichloride 1.48 mmol and meso-dimethylsilylene (2,3,5-trimethylcyclopentadienyl) (2 ', 3', 5'-trimethylcyclopentadienyl) A mixture of hafnium dichloride 0.05 mmol was added at 20 ° C. together with toluene 1 dm ³ . Subsequently, the temperature inside the polymerization vessel was set to 27 ° C., hydrogen was supplied so that the hydrogen partial pressure in the gas phase inside the polymerization vessel was 0.01 MPa, and then the pressure inside the polymerization vessel was maintained at 0.4 MPa. Propylene was continuously fed into the polymerization vessel for 4 hours to polymerize propylene. During the polymerization, the temperature in the polymerization vessel was set to 27 ° C.
Kept at. After completion of the polymerization, unreacted propylene was discharged from the inside of the polymerization reactor, 2-propanol 3dm ³ was charged into the polymerization reactor, and the mixture was stirred at 30 ° C. for 10 minutes to deactivate the catalyst. Subsequently, an aqueous solution of hydrogen chloride (concentration: 12 mol / dm ³ )
It was added 0.2Dm ³ and methanol 8dm ^3, 60 ℃
For 30 minutes. After the treatment, the stirring was stopped, the aqueous phase was removed from the lower part of the polymerization vessel, and the same operations were repeated by adding the same amount of aqueous hydrogen chloride solution and methanol. Then, a sodium hydroxide aqueous solution (concentration: 5 mol / dm ³ ) was added.
02 dm ³ , water 2 dm ³ , and methanol 2 dm ^{3 were} added, and the mixture was stirred at 30 ° C. for 10 minutes. After the treatment, stirring was stopped to remove the aqueous phase portion from the lower part of the polymerization vessel, 8 dm ³ of water was further added, the mixture was stirred for 10 minutes at 30 ° C., and the operation of removing the aqueous phase portion was repeated twice. The slurry was extracted from the polymerization vessel, filtered and dried to obtain 5.0 kg of the stereoregular polypropylene of the present invention. Physical properties of the obtained polypropylene were measured by the methods described above. (2) Manufacture of molded article-1 Tetrakis [methylene-3- (3'-5'-di-t-butyl-4'-hydroxyphenyl) propionate] methane 0.1 was added to 100 parts by weight of the obtained polypropylene. Parts by weight,
0.1 parts by weight of calcium stearate and 0.1 parts by weight of talc as a foaming nucleating agent were mixed, and polypropylene pellets were mixed with the mixture using a single screw extruder having a screw diameter of 40 mm and an extrusion temperature of 230 ° C. Obtained.
Molten resin temperature of polypropylene pellets by injection molding machine 2
A JIS type test piece was prepared at 30 ° C. and a mold temperature of 50 ° C. The high temperature rigidity was measured for the above test piece. (2) Manufacture of molded product-2 Polypropylene pellets obtained in the same manner as in (1) above were heated and melted under a condition of 230 ° C and 4.0 MPa for 3 minutes with a press machine, and then 30 ° C and 14.8 MPa. After cooling under the conditions of 3 minutes, the thickness taken out from the mold is 0.5m
A compression molded sheet of m was obtained. 50m from the above sheet
A toughness was measured by punching out a test piece measuring m and a width of 6 mm.

Comparative Example 1 (1) Manufacture of Polypropylene In place of metallocene and methylaluminoxane as the catalyst in (1) of Example 1, JP-A-62-10481 was used.
The magnesium chloride-supporting titanium catalyst component obtained by the same method as in Example 1 in JP-A-2 is 3.3 in terms of Ti.
mmol, triethylaluminum 100 mmol,
And a catalyst in which 10 mmol of diisopropyldimethoxysilane was combined as the third component of the catalyst, the hydrogen partial pressure before the initiation of polymerization was 0.02 MPa, and the polymerization temperature was 70.
Polymerization of propylene was carried out in the same manner except that the temperature was adjusted to 0 ° C to obtain polypropylene. Physical properties of the obtained polypropylene were measured in the same manner as in Example 1. (2) Manufacture of Molded Article-1 With respect to the polypropylene obtained in (1) above, injection molded test pieces were obtained in the same manner as in (2) of Example 1 and evaluated for high temperature rigidity. (3) Manufacture of molded product-2 With respect to the polypropylene obtained in (1) above, a compressed sheet test piece was obtained in the same manner as in (2) of Example 1 and evaluated for toughness.

Comparative Example 2 (1) Production of polypropylene Using the same polymerization vessel as used in (1) of Example 1, polypropylene was obtained by the method according to Example 4 in JP-A-3-12407. It was That is, toluene 50 dm, a toluene solution of methylaluminoxane in a polymerization vessel (manufactured by Tosoh Akzo Co., Ltd., trade name: MMAO, concentration: 2
mol / dm ³ ) is 7.3 mol in terms of Al atom, and chiral dimethylsilylene (2,3,5-) as metallocene.
Trimethylcyclopentadienyl) (2 ', 4', 5 '
-Trimethylcyclopentadienyl) hafnium dichloride 1.42 mmol and meso dimethylsilylene (2,3,5-trimethylcyclopentadienyl)
A mixture of (2 ′, 3 ′, 5′-trimethylcyclopentadienyl) hafnium dichloride 0.05 mmol was added at 20 ° C. together with toluene 0.1 dm ³ . Subsequently, the temperature in the polymerization vessel was set to 30 ° C., and propylene was continuously supplied into the polymerization vessel for 4 hours so that the pressure in the polymerization vessel was kept at 0.4 MPa without supplying hydrogen into the polymerization vessel. Then, propylene was polymerized. During the polymerization, the temperature in the polymerization vessel was kept at 30 ° C. After completion of the polymerization, unreacted propylene was discharged from the inside of the polymerization vessel, ³ dm ³ of methanol was added to the inside of the polymerization vessel, the catalyst was decomposed, and filtration and drying were performed to obtain polypropylene. Physical properties of the obtained polypropylene were measured in the same manner as in Example 1.

Example 2 (1) Production of polypropylene After a stainless steel polymerization vessel equipped with a stirrer and having an internal volume of 100 dm ³ equipped with a stirrer was replaced with nitrogen gas, a toluene solution of methylaluminoxane (manufactured by Tosoh Akzo, trade name:
MMAO, concentration: 2 mol / dm ³ ) was 11 mol in terms of Al atom, and the hydrogen partial pressure in the polymerization vessel was 0.
Hydrogen was charged into the polymerization vessel so as to be 03 MPa, and then 30 kg of liquefied propylene was supplied, and then a toluene solution of methylaluminoxane (manufactured by Tosoh Akzo Co., Ltd., trade name: M
MAO, concentration: 2 mol / dm ³ ) 1 in terms of Al atoms
1 mol, chiral dimethylsilylene as metallocene (2,3,5-trimethylcyclopentadienyl)
(2 ′, 4 ′, 5′-Trimethylcyclopentadienyl) zirconium dichloride 0.033 mmol and meso dimethylsilylene (2,3,5-trimethylcyclopentadienyl) (2 ′, 3 ′, 5 ′) A mixture of 0.002 mmol of -trimethylcyclopentadienyl) zirconium dichloride and 0.1 dm ³ of toluene was injected into the polymerization vessel by pressurizing nitrogen at 20 ° C. to initiate the polymerization of propylene. During the polymerization, the temperature in the polymerization vessel should be 3
It was kept at 0 ° C. After the lapse of 4 hours from the start of the polymerization, 2-propanol ³ dm ³ was press-fitted into the polymerization vessel and the polymerization was stopped at 30 ° C. for 5 minutes. Subsequently, 50 dm ³ of n-hexane was put into the polymerization vessel, and thereafter the same post-treatment as in Example 1 was performed to obtain 6.6 kg of stereoregular polypropylene of the present invention. Physical properties of the obtained polypropylene were measured in the same manner as in Example 1. (2) Manufacture of Molded Article-1 With respect to the polypropylene obtained in (1) above, injection molded test pieces were obtained in the same manner as in (2) of Example 1 and evaluated for high temperature rigidity. (3) Manufacture of molded product-2 With respect to the polypropylene obtained in (1) above, a compressed sheet test piece was obtained in the same manner as in (2) of Example 1 and evaluated for toughness.

Example 3 (1) Production of Polypropylene Polypropylene was obtained in the same manner as in (1) of Example 1. (2) Production of molded product-3 Polypropylene pellets were obtained in the same manner as in (2) of Example 1. Screw the polypropylene pellets with a screw diameter of 40
The film was extruded at 250 ° C. using a T-die type film forming machine of mm, and a sheet having a thickness of 820 μm was prepared with a cooling roll at 25 ° C. (3) Manufacture of molded product-4 The sheet obtained in (2) above was heated at 158 ° C for 90 seconds, and was stretched 4.2 times in the machine direction at a stretching speed of 5 m / min using a biaxial stretching machine, Direction of 8.2 times, and 23 μm thick 2
An axially stretched film was obtained. The evaluation results of the film measured according to the method described above are shown in Table 2.

Comparative Example 3 (1) Production of Polypropylene Polypropylene was obtained in the same manner as in (1) of Comparative Example 1. (2) Production of molded product-3 A sheet was obtained in the same manner as in (2) of Example 3 except that the polypropylene obtained in (1) above was used as the polypropylene. (3) Production of molded product-4 A biaxially stretched film was obtained in the same manner as in (3) of Example 3 except that the sheet obtained in (2) above was used. The evaluation results of the obtained film are shown in Table 2.

Comparative Example 4 (1) Production of Polypropylene In Example 1, as the metallocene, chiral rac-
1.32 mmol of ethylenebis (indenyl) hafnium dichloride and meso-ethylenebis (indenyl) hafnium dichloride which is a meso form 0.15 mm
Polymerization and post-treatment of propylene were carried out in the same manner except that a mixture of ol was used and the hydrogen partial pressure before the initiation of polymerization was 0.04 MPa to obtain polypropylene. Physical properties of the obtained polypropylene were measured in the same manner as in Example 1. (2) Production of molded product-3 A sheet was obtained in the same manner as in (2) of Example 3 except that the polypropylene obtained in (1) above was used as the polypropylene. (3) Manufacture of molded product-4 In Example 3 (3), the biaxially stretched film was evaluated in the same manner except that the sheet obtained in (2) above was used as the sheet. Since the sheet drooped downward in the process, it was impossible to stretch and the film could not be formed.

The above Examples 1 to 3 and Comparative Examples 1 to 4
The evaluation results of are shown in Table 1 and Table 2.

[0056]

[Table 1]

[0057]

[Table 2]

[0058]

The polypropylene molded product of the present invention is excellent in high temperature characteristics such as rigidity at high temperature, toughness and chemical stability, and can be used in fields or applications not used in conventional polypropylene molded products. Is.

[Brief description of drawings]

1 shows a ¹³ C nuclear magnetic resonance spectrum of polypropylene used in the molded article of the present invention described in Example 1. FIG.

Claims (1)

[Claims] 1. The general formula Q (C ₅ H _4-m R ¹ _m ) (C ₅ H _4-n R
² _n ) a chiral transition metal compound represented by MXY, wherein (C ₅ H _4-m R ¹ _m ) and (C ₅ H _4-n R ² _n ) represent a substituted cyclopentadienyl group. , M and n are integers of 1 to 3. R ¹ and R ² are a hydrocarbon group having 1 to 20 carbon atoms, a silicon-containing hydrocarbon group, or one which may be bonded to two carbon atoms on the cyclopentadienyl ring and substituted with a hydrocarbon. The hydrocarbon groups forming the above hydrocarbon ring may be the same or different. Q is a divalent hydrocarbon group, an unsubstituted silylene group, or a hydrocarbon-substituted silylene group, both of which crosslink (C ₅ H _4-m R ¹ _m ) and (C ₅ H _4-n R ² _n ). is there. M represents a transition metal such as titanium, zirconium or hafnium, and X and Y may be the same or different and each represents hydrogen, halogen or a hydrocarbon group. ] And aluminoxane were used to polymerize propylene in the presence of hydrogen to obtain an isotactic pentad fraction (mmmm) of 0.950 to 0.995 and a syndiotactic pentad fraction (rrrr). ) Is 0 to 0.01, and the heterologous bond resulting from the 2,1 insertion reaction and the 1,3 insertion reaction is 0 to 0.
3 mol%, there is no terminal double bond, the weight average molecular weight (Mw) is 50,000 to 1,000,000, and the number average molecular weight (Mw) of the weight average molecular weight (Mw).
A polypropylene molded article consisting essentially of polypropylene having a ratio (Mw / Mn) to n) of 1.5 to 3.8.