JP2000169534A - Production of propylene/ethylene block copolymer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a process for producing a propylene/ethylene block copolymer which has a high stereoregularity and a board distribution of molecular weight and is excellent in rigidity and impact resistance while easily effecting molecular weight modification with hydrogen. SOLUTION: A process for producing a propylene/ethylene block copolymer comprises effecting the first polymerization step of polymerizing propylene alone or an α-olefin other than propylene to 10-90 wt.% total polymerization amount, and successively the second polymerization step of polymerizing propylene and ethylene to 10-50 wt.% total polymerization amount, in the presence of an olefin polymerization catalyst comprising, a solid titanium compound as component (A); an organoaluminum compound represented by formula I: R3Al (wherein R is a 1-10C alkyl group) as component (B); and an organosilicon compound represented by formula II (wherein n is an integer of 2-6; R1 and R2 are each a hydrogen or a methyl group; R3 and R4 are the same or different 1-4C alkyl groups, 3-6C cycloalkyl groups or aryl groups; and R5 is a 1-3C alkyl group) as component (C).

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to a propylene-ethylene block copolymer having high stereoregularity and a wide molecular weight distribution, and having excellent rigidity and impact resistance, having high polymerization activity.
The present invention relates to a method for producing while easily controlling the molecular weight with hydrogen.

[0002]

2. Description of the Related Art Polypropylene is widely used as a packaging material for sheets, films and the like, as well as structural materials such as automobile parts and household electric appliances. In recent years, particularly in the field of structural materials, high rigidity, heat resistance, and impact resistance have been required, and the need for polypropylene that satisfies these requirements has been increasing.

As a method for improving the rigidity, heat resistance, impact resistance and the like of polypropylene, a propylene block copolymer prepared by multistage polymerization of a copolymer component of propylene and an α-olefin other than propylene in addition to a polypropylene component is known. Is known.

In order for these propylene block copolymers to exhibit excellent characteristics such as rigidity, heat resistance, and low-temperature characteristics, they must have high melting point and stereoregularity, and must have propylene and an α-olefin other than propylene. It is necessary that the molecular weight of the copolymer component is relatively large and the copolymer composition is in an appropriate range.

[0005] In recent years, the demands on the physical properties of propylene block copolymers have become more severe, and there has been a demand for a method for stably producing a copolymer having a better balance of physical properties at a high yield. The proposal has been made. For example,
JP-B-36-15284, JP-B-38-14834
JP, JP-A-53-35788, JP-A-53-35
789 and JP-A-56-35789. As a result, the impact resistance of polypropylene is improved to some extent, but on the other hand, the rigidity and heat resistance are significantly reduced, and the rigidity, heat resistance, and impact resistance have not been simultaneously satisfied.

On the other hand, various proposals have been made for a propylene block copolymer having both high rigidity and high impact properties. For example, JP-A-61-252218 discloses that a solid titanium compound, an organoaluminum compound, and a catalyst component comprising an organosilicon compound are used.
In the first step of polymerization, propylene is homopolymerized,
Then, it is disclosed that the block copolymer obtained by copolymerizing propylene and ethylene in the second step exhibits excellent rigidity, heat resistance and impact resistance.

Further, JP-A-2-84404 and JP-A-4-202505 disclose solid titanium compounds and organoaluminum compounds and cyclopentylalkyldimethoxysilane, dicyclopentyldimethoxysilane, di (substituted cyclopentyl) dimethoxy as the third component. A method for producing a propylene block copolymer having extremely high stereoregularity, excellent rigidity and excellent heat resistance by using a catalyst system composed of a specific organic silicon compound such as silane is disclosed. Generally, in order to improve the melt flowability of a polymer, a method of increasing the melt flow rate of a polymer by using a molecular weight modifier such as hydrogen has been adopted.However, the above-mentioned catalyst system has a hydrogen dependence on the melt flow rate. Therefore, a large amount of hydrogen is required to improve the melt fluidity. Particularly, in a production process currently used industrially, it is often difficult to fill a large amount of hydrogen due to a problem of pressure resistance of a polymerization apparatus, and this is a great problem in obtaining a polymer having excellent melt fluidity. Had been a problem. Furthermore, when a decomposing agent such as an organic peroxide is used for the purpose of increasing the melt flow rate of the polymer obtained by these catalyst systems, the molecular weight distribution becomes narrow,
Furthermore, since the molecular weight of the copolymer component also decreases, there are problems such as a decrease in rigidity, impact resistance, and melt fluidity, and a solution thereof has been desired.

[0008]

Accordingly, an object of the present invention is to provide a propylene-ethylene block copolymer having high stereoregularity and a wide molecular weight distribution, and having excellent rigidity and impact resistance, with high polymerization activity. It is another object of the present invention to provide a method for producing while easily controlling the molecular weight with hydrogen.

[0009]

The object of the present invention can be achieved by the following constitution.

That is, the present invention relates to: [A] component: a solid titanium compound [B] component: an organoaluminum compound represented by the general formula [I] R ₃ Al [I] (where R is 1 to 10 carbon atoms) [C] component: an organosilicon compound represented by the general formula [II]

[0011]

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(Where n is an integer of 2 to 6,
R ^1, R ² is hydrogen or a methyl group, R ^3, R ⁴ is an alkyl group, cyclic alkyl group or aryl group having 3 to 6 carbon atoms having 1 to 4 carbon atoms the same or different, R ⁵ is Carbon number 1
3 alkyl groups. ) In the presence of the olefin polymerization catalyst represented by the polymerization in the first step of the polymerization of propylene alone or propylene and α- olefins other than propylene to 50-90 wt% of the total polymerization amount, Next, in a second step of the polymerization, a method for producing a propylene-ethylene block copolymer, wherein the polymerization of propylene and ethylene is carried out so as to be 10 to 50% by weight of the total polymerization amount.

[0013]

DESCRIPTION OF THE PREFERRED EMBODIMENTS As the solid titanium compound used in the present invention, known compounds are used without any particular limitation as long as they contain magnesium, titanium, halogen and an electron donor as essential components.

Many methods for producing such a solid titanium compound have been proposed so far, and in the present invention, the solid titanium compound obtained by these known methods is used without any limitation. For example, a method in which a titanium compound such as a titanium tetrahalide is co-ground with a magnesium compound in the presence of an electron donor, a method in which a titanium compound, a magnesium compound and an electron donor are brought into contact in a solvent, and the like are exemplified.

The method for preparing these solid titanium compounds is as follows:
For details, see JP-A-56-155206 and JP-A-56-155206.
136806, 57-34103, 5
Nos. 8-8706 and 58-83006, 5
JP-A-8-138708, JP-A-58-183709, JP-A-59-206408, and JP-A-59-21931.
No. 1, No. 60-81208, No. 60-812
Nos. 09, 60-186508 and 60-1
Nos. 92708, 61-21309, 6
JP-A-271304, JP-A-62-15209,
It is disclosed in JP-A-62-1706, JP-A-62-72702, JP-A-62-104810 and the like.

As the titanium compound used for preparing the solid titanium compound, a tetravalent titanium compound is used. As such a tetravalent titanium compound, titanium halides such as tetrahalogenated titanium, tetraalkoxytitanium, trihalogenated alkoxytitanium, dihalogenated dialkoxytitanium and halogenated trialkoxytitaniums can be used. Specific examples of such compounds include tetrachlorotitanium, tetrabromotitanium, tetraiodotitanium,
Tetramethoxytitanium, tetraethoxytitanium, tetra-n-propoxytitanium, tetra-i-propoxytitanium,
Tetra n-butoxytitanium, tetra i-butoxytitanium, tetra n-hexyloxytitanium, tetra n-octyloxytitanium, trichloroethoxytitanium, dichlorodiethoxytitanium, triethoxychlorotitanium, trichloron-butoxytitanium, dichlorodin-butoxytitanium Titanium, tri-n-butoxychlorotitanium and the like are produced.

The magnesium compound used for preparing the solid titanium compound described above includes magnesium halide such as magnesium chloride, alkoxymagnesium such as magnesium diethoxide, alkoxymagnesium halide, magnesium oxide, magnesium hydroxide, magnesium hydroxide and the like. Carboxylates and the like can be used. Further, as the electron donor used for preparing the solid titanium compound, known electron donors are used without any particular limitation.
For example, alcohols, phenols, ketones, aldehydes, carboxylic acids, organic acid halides, esters of organic or inorganic acids, ethers, acid amides, acid anhydrides, amines, nitriles, isocyanates , Ammonia and the like.

Of these, esters of organic acids are preferred, and those having two or more ester bonds in the molecule are particularly preferred.

Specific examples of such a compound having two or more ester bonds in the molecule include diethyl succinate, dibutyl succinate, diethyl methyl succinate, and the like.
Diisobutyl α-methylglutarate, diethyl methylmalonate, diethyl ethylmalonate, diethyl isopropylmalonate, diethyl butylmalonate, diethyl phenylmalonate, diethyl diethylmalonate, diethyldibutylmalonate, monooctyl maleate, dioctyl maleate Aliphatic polycarboxylic acid esters such as dibutyl maleate, dibutyl butyl maleate, diethyl butyl maleate, diisopropyl β-methylglutarate, diallyl ethyl succinate, di-2-ethylhexyl fumarate, diethyl itaconate, and dioctyl citraconic acid; diethyl 1,2-cyclohexanecarboxylate, 1,
Alicyclic polycarboxylic acid esters such as diisobutyl 2-cyclohexanecarboxylate, diethyl tetrahydrophthalate, diethyl nadicate, monoethyl phthalate, dimethyl phthalate, methylethyl phthalate, monoisobutyl phthalate, diethyl phthalate, phthalic acid Ethyl isobutyl, di-n-propyl phthalate, diisopropyl phthalate, di-n-butyl phthalate, diisobutyl phthalate, di-n-heptyl phthalate, di-2-ethylhexyl phthalate, di-n-octyl phthalate, dineopentyl phthalate And aromatic polycarboxylic esters such as didecyl phthalate, benzyl butyl phthalate, diphenyl phthalate, diethyl naphthalene dicarboxylate, dibutyl naphthalene dicarboxylate, triethyl trimetate and dibutyl trimetate. Door can be.

Other examples of the compound having two or more ester bonds in the molecule include diethyl adipate,
Diisobutyl adipate, diisopropyl sebacate,
Di-n-butyl sebacate, di-n-octyl sebacate,
Long chain dicarboxylic acid esters such as di-2-ethylhexyl sebacate can be mentioned.

Of these, the use of phthalic esters is most preferable because it is effective in the effects of the present invention.

The organoaluminum compound used in the present invention includes a trialkylaluminum represented by the following general formula [I].

R ₃ Al [I] In the above general formula [I], R is a saturated alkyl group having 1 to 10 carbon atoms. Examples of the saturated alkyl group having 1 to 10 carbon atoms include a methyl group, an ethyl group, a propyl group, an isopropyl group, a butyl group, an isobutyl group, a sec-butyl group and a t-
Butyl, pentyl, isopentyl, neopentyl, hexyl, heptyl, octyl, nonyl,
Examples include a chain alkyl group such as a decyl group, a cyclopentyl group, and a cyclohexyl group, and a cyclic alkyl group.

Specific examples of the trialkylaluminum compounds which can be used particularly preferably include, for example, trimethylaluminum, triethylaluminum, tri-n-propylaluminum, tri-nbutylaluminum, tri-ibutylaluminum, tri-n Hexyl aluminum, tri-n-octyl aluminum,
Tri-n-decyl aluminum and the like.

The amount of the organoaluminum compound used in the olefin polymerization catalyst of the present invention is 1 / Al / Ti (molar ratio) with respect to the titanium atom in the titanium compound.
１０００1000, preferably 5-500.

In the present invention, the organosilicon compound used for the olefin polymerization catalyst is a silicon compound represented by the following general formula [II].

[0027]

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In the general formula [II], R ¹ and R ² are the same or different hydrogen or methyl groups. R ³ and R ⁴ are the same or different and are a linear or branched alkyl group having 1 to 4 carbon atoms, a cyclic alkyl group or an aryl group having 3 to 6 carbon atoms.

As the chain or branched alkyl group having 1 to 4 carbon atoms, there can be mentioned a methyl group, an ethyl group, a propyl group, an isopropyl group, a butyl group, an isobutyl group, a sec-butyl group and a t-butyl group. In addition, carbon number 3-6
Examples of the cyclic alkyl group include a cyclopropyl group, a cyclobutyl group, a cyclopentyl group, and a cyclohexyl group. Of these, a cyclopentyl group and a cyclohexyl group are particularly preferred from the viewpoint of production. The aryl group includes a phenyl group.

R ⁵ is an alkyl group having 1 to 3 carbon atoms.
Examples of the alkyl group having 1 to 3 carbon atoms include a methyl group, an ethyl group, and a propyl group.

More specifically, examples of such an organosilicon compound include the following compounds.

N, N'-dimethylethylenediaminodimethoxysilane, N, N'-dimethyl-1,2-dimethylethylenediaminodimethoxysilane, N, N'-dimethyl-1,1,2,2-tetramethyl Ethylenediaminodimethoxysilane, N, N′-diethylethylenediaminodimethoxysilane, N, N′-diethyl-1,2,2
-Dimethylethylenediaminodimethoxysilane, N,
N'-diethyl-1,1,2,2-tetramethylethylenediaminodimethoxysilane, N, N'-dinpropylethylenediaminodimethoxysilane, N, N'-din
Propyl-1,2, -dimethylethylenediaminodimethoxysilane, N, N'-dinpropyl-1,1,2,2
2, -tetramethylethylenediaminodimethoxysilane, N, N'-diisopropylethylenediaminodimethoxysilane, N, N'-dipropyl-1,2, -dimethylethylenediaminodimethoxysilane, N, N'-dii
Propyl-1,1,2,2-tetramethylethylenediaminodimethoxysilane, N, N′-dibutylethylenediaminodimethoxysilane, N, N′-dibutyl-1,
2, -dimethylethylenediaminodimethoxysilane,
N, N'-dibutyl-1,1,2,2-tetramethylethylenediaminodimethoxysilane, N, N'-diibutylethylenediaminodimethoxysilane, N, N'-diibutyl-1,2,- Dimethylethylenediaminodimethoxysilane, N, N'-diibutyl-1,1,2,2
-Tetramethylethylenediaminodimethoxysilane,
N, N'-disbutylethylenediaminodimethoxysilane, N, N'-disbutyl-1,2-dimethylethylenediaminodimethoxysilane, N, N'-disbutyl-
1,1,2,2-tetramethylethylenediaminodimethoxysilane, N, N'-di-t-butylethylenediaminodimethoxysilane, N, N'-di-t-butyl-1,2,-
Dimethylethylenediaminodimethoxysilane, N, N '
-Di-t-butyl-1,1,2,2-tetramethylethylenediaminodimethoxysilane, N, N'-dimethyl1,
3-propanediaminodimethoxysilane, N, N'-diethyl-1,3-propanediaminodimethoxysilane,
N, N'-dipropyl-1,3-propanediaminodimethoxysilane, N, N'-diisopropyl-1,3-propanediaminodimethoxysilane, N, N'-dibutyl-
1,3-propanediaminodimethoxysilane, N, N '
-Dibutyl-1,3-propanediaminodimethoxysilane, N, N'-disbutyl-1,3-propanediaminodimethoxysilane, N, N'-ditertbutyl-1,3-
Propanediaminodimethoxysilane, N, N'-dimethyl-2-methyl-1,3-propanediaminodimethoxysilane, N, N'-diethyl-2-methyl-1,3-
Propanediaminodimethoxysilane, N, N'-dipropyl-2-methyl-1,3-propanediaminodimethoxysilane, N, N'-diisopropyl-2-methyl-
1,3-propanediaminodimethoxysilane, N, N '
-Dibutyl-2-methyl-1,3-propanediaminodimethoxysilane, N, N'-diibutyl-2-methyl-1,3-propanediaminodimethoxysilane, N,
N'-disbutyl-2-methyl-1,3-propanediaminodimethoxysilane, N, N'-ditbutyl-2-methyl-1,3-propanediaminodimethoxysilane,
N, N'-dimethyl-2,2-dimethyl-1,3-propanediaminodimethoxysilane, N, N'-diethyl-
2,2-dimethyl-1,3-propanediaminodimethoxysilane, N, N'-dipropyl-2,2-dimethyl-
1,3-propanediaminodimethoxysilane, N, N '
-Dipropyl-2,2-dimethyl-1,3-propanediaminodimethoxysilane, N, N'-dibutyl-2,
2-dimethyl-1,3-propanediaminodimethoxysilane, N, N′-diibutyl-2,2-dimethyl-1,
3-propanediaminodimethoxysilane, N, N′-disbutyl-2,2-dimethyl-1,3-propanediaminodimethoxysilane, N, N′-ditbutyl-2,2-
Dimethyl-1,3-propanediaminodimethoxysilane, N, N'-dimethyl-1,4-butanediaminodimethoxysilane, N, N'-diethyl-1,4-butanediaminodimethoxysilane, N, N'-dipropyl- 1,
4-butanediaminodimethoxysilane, N, N'-dii
Propyl-1,4-butanediaminodimethoxysilane,
N, N'-dibutyl-1,4-butanediaminodimethoxysilane, N, N'-diibutyl-1,4-butanediaminodimethoxysilane, N, N'-disbutyl-1,4
-Butanediaminodimethoxysilane, N, N'-ditertbutyl-1,4-butanediaminodimethoxysilane, N,
N'-dimethyl-1,5-pentanediaminodimethoxysilane, N, N'-diethyl-1,5-pentanediaminodimethoxysilane, N, N'-dipropyl-1,5-
Pentanediaminodimethoxysilane, N, N'-diisopropyl-1,5-pentanediaminodimethoxysilane,
N, N'-dibutyl-1,5-pentanediaminodimethoxysilane, N, N'-diibutyl-1,5-pentanediaminodimethoxysilane, N, N'-disbutyl-
1,5-pentanediaminodimethoxysilane, N, N '
-Di-t-butyl-1,5-pentanediaminodimethoxysilane, N, N'-dimethyl-1,6-hexanediaminodimethoxysilane, N, N'-diethyl-1,6-hexanediaminodimethoxysilane, N, N ' -Dipropyl-1,6-hexanediaminodimethoxysilane, N,
N′-diipropyl-1,6-hexanediaminodimethoxysilane, N, N′-dibutyl-1,6-hexanediaminodimethoxysilane, N, N′-diibutyl-1,
6-hexanediaminodimethoxysilane, N, N'-disbutyl-1,6-hexanediaminodimethoxysilane, N, N'-ditbutyl-1,6-hexanediaminodimethoxysilane, N, N'-dicyclo Propylethylenediaminodimethoxysilane, N, N'-dicyclobutylethylenediaminodimethoxysilane, N, N'-dicyclopentylethylenediaminodimethoxysilane,
N'-dicyclohexylethylenediaminodimethoxysilane, N, N'-diphenylethylenediaminodimethoxysilane, and the like.

In particular, N, N'-dimethylethylenediaminodimethoxysilane, N, N'-dimethyl-1,
1,2,2, -tetramethylethylenediaminodimethoxysilane, N, N'-diipropylethylenediaminodimethoxysilane, N, N'-dimethyl-1,3-propanediaminodimethoxysilane, N, N'-dimethyl-
1,4-butanediaminodimethoxysilane, N, N'-
Dicyclopentylethylenediaminodimethoxysilane,
N, N'-dicyclohexylethylenediaminodimethoxysilane, N, N'-diphenylethylenediaminodimethoxysilane and the like are preferable.

The amount of the organosilicon compound represented by the above general formula [II] is 0.01 to 10, preferably 0.01 to 1.0, in a molar ratio to the organoaluminum compound.
It is.

By performing the polymerization of polyolefin using the olefin polymerization catalyst of the present invention, a propylene-ethylene block copolymer having high stereoregularity, a wide molecular weight distribution, and excellent rigidity and impact resistance can be obtained. It can be produced with high polymerization activity while easily controlling the molecular weight with hydrogen.

Using the olefin polymerization catalyst comprising a solid titanium compound, an organoaluminum compound and a specific organosilicon compound, which can be obtained by the above method, a propylene component and conditions for polymerizing propylene and ethylene (main polymerization) A known method can be employed, but generally the following conditions are preferable.

In the production of the propylene-ethylene block copolymer of the present invention, it is preferable that the propylene component is polymerized in the first step and that propylene and ethylene are polymerized in the second step. Further, the polymerization in the first step and the polymerization in the second step can be performed in two or more stages under different conditions.

The polymerization in the first step may be a homopolymerization of propylene or a copolymerization of propylene with an α-olefin other than propylene. As α-olefins other than propylene, ethylene, 1-butene, 1-pentene,
1-hexene, 3-methyl-1-butene, 4-methyl-
Examples thereof include linear olefins such as 1-pentene and 1-octene. Therefore, the monomer polymerized in the first step is called a propylene component, and the polymer is called a polypropylene component.

The polymerization ratio of the α-olefin in the polypropylene component obtained in the first step is preferably 10% by weight or less. If the polymerization ratio of the α-olefin other than propylene in the polypropylene component exceeds 10% by weight, low crystalline by-products increase, and the crystallinity of the polypropylene component is remarkably reduced.

The polymerization rate in the first step of the main polymerization is generally adjusted in the range of 10 to 1000 g-polymer / g-catalyst, preferably 50 to 700 g-polymer / g-catalyst. .

The polymerization in the second step is a copolymerization of propylene and ethylene. Usually, after the end of the first step, ethylene is supplied to a place where the propylene component remains. The supply amount of ethylene can be determined as appropriate, but usually the molar ratio of propylene to ethylene is 9%.
0/10 to 30/70, preferably 80/20 to 30 /
70 is set. Further, after purging the propylene component in the first step, polymerization may be carried out as it is or after moving to another reactor, mixing and supplying new propylene / ethylene in the above range.

The polymerization temperature in the first and second steps of the main polymerization is 20 to 200 ° C., preferably 50 to 150 ° C., respectively.
° C, and hydrogen may be allowed to coexist as a molecular weight regulator. In the main polymerization, slurry polymerization, solvent-free polymerization, and gas phase polymerization can be applied in the first step and the second step, respectively, and any of a batch system, a semi-batch system, and a continuous system may be used. And each of the second steps can be performed in two or more stages having different conditions.

The polymerization time may be appropriately determined in consideration of the above polymerization temperature and polymerization mode, but is usually from 30 minutes to 1 minute.
0 hour, preferably set in the range of 1 hour to 5 hours, the time ratio of the first step and the second step, the polypropylene component of the propylene-ethylene block copolymer of the present invention and the copolymer component It can be appropriately determined within a range that satisfies the constitutional ratio, but it is usually preferable that the time ratio of the first step and the second step is set to 80/20 to 10/90 in terms of the polymerization time ratio.

In the present invention, the above [A] [B] and [C]
The polymerization of the olefin is carried out in the presence of the olefin polymerization catalyst of the present invention comprising the components, and may be subjected to a preliminary polymerization prior to the polymerization.

For such prepolymerization, a known method for polymerizing an olefin in the presence of the above-mentioned titanium compound, organoaluminum compound or organosilicon compound can be employed without any limitation, but the following method is preferred.

That is, in general, the amount of the organoaluminum compound used in the prepolymerization is such that A1 atom in the organoaluminum is A with respect to Ti atom in the solid titanium compound component.
1 / Ti (molar ratio) is preferably from 1 to 100, and more preferably from 3 to 10.

In the prepolymerization, other organoaluminum compounds such as halogenated organoaluminum compounds may be present as long as the action of the organoaluminum compound is not significantly impaired. Generally, such proportions are up to 200% by weight, based on the organoaluminum compound having substantially no halogen atoms.

The use of the organosilicon compound used in the prepolymerization is not particularly limited, but generally, Si / T is used for the Ti atom in the solid titanium compound component.
i (molar ratio) It is preferably from 1 to 20, and more preferably from 0.5 to 5.

In addition to the solid titanium compound [A], organoaluminum compound [B] and organosilicon compound [C], the following general formula [III] R ⁶ -I [III] (where R ⁶ is an iodine atom Or a hydrocarbon group.) Is preferable because the stereoregularity of the obtained polymer can be further increased.

The hydrocarbon group for R ⁶ has 1 to 1 carbon atoms.
Alkyl group, alkenyl group, alkynyl group, aryl group and the like.

Examples of the iodine compound represented by the general formula [III] include iodine, methyl iodide, ethyl iodide, propyl iodide, butyl iodide, iodobenzene, p-iodide toluene and the like.

Among them, methyl iodide and ethyl iodide are preferred. The amount of the iodine compound used in the prepolymerization step is I / Ti (molar ratio) with respect to the Ti atom in the titanium compound.
And 0.1 to 100, preferably 0.5 to 50.

Further, the amount of the olefin polymerized in the prepolymerization is 0.1 to 100 g per 1 g of the solid titanium compound component,
It is preferably a pure range of 1 to 100 g, and industrially 2 to 100 g.
A range of 50 g is preferred. As the olefin used in the prepolymerization, ethylene, propylene, 1-butene, 1-
Examples thereof include linear olefins such as pentene and 1-hexene.

In this case, it is possible to use two or more of the above-mentioned olefins at the same time, and it is also possible to use different olefins at each stage by performing the prepolymerization stepwise. In consideration of the improvement in the stereoregularity of the obtained polymer, it is preferable to use a specific type of olefin at 90 mol% or more. It is also possible to make hydrogen coexist in the preliminary polymerization.

The prepolymerization has a polymerization rate of 0.001 to 0.001.
It is preferable to carry out in the range of 1.0 g-polymer / g-catalyst-minute, and in order to achieve such a polymerization rate, usually, slurry polymerization is most suitably employed. In this case, a saturated aliphatic hydrocarbon or an aromatic hydrocarbon such as hexane, heptane, cyclohexane, benzene, and toluene can be used alone or in combination.

The temperature in the slurry polymerization is generally one to two.
The temperature is preferably from 0 to 100 ° C., particularly preferably from 0 to 60 ° C. When preliminary polymerization is carried out in multiple stages, it may be carried out under different temperature conditions in each stage. The polymerization time may be appropriately determined according to the polymerization temperature and the polymerization. Further, the polymerization pressure is not limited, but is generally from atmospheric pressure to about 5 kg / cm 2.

The prepolymerization may be carried out in any of batch, semi-batch and continuous methods.

Although the preliminary polymerization method by slurry polymerization has been described above, it is also possible to carry out the preliminary polymerization by gas phase polymerization or solventless polymerization.

After obtaining a solid titanium catalyst by the above prepolymerization, the solid titanium catalyst is used alone or as a mixture of saturated aliphatic hydrocarbons or aromatic hydrocarbons such as hexane, heptane, cyclohexane, benzene and toluene. And
Washing is preferred to obtain an olefin polymerization catalyst having higher polymerization activity. The number of times of such washing is usually preferably 5 to 6 times.

[0060]

According to the present invention, there is provided a propylene-ethylene block copolymer having high stereoregularity and a wide molecular weight distribution, and having excellent rigidity and impact resistance.

According to the present invention, there is also provided a method for producing a propylene-ethylene block copolymer having the above-mentioned properties with high polymerization activity and easily controlling the molecular weight with hydrogen.

[0062]

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

The measuring methods used in the following examples and comparative examples are as follows.

(1) Soluble amount of p-xylene 1 g of the polymer was added to 100 cc of p-xylene, the temperature was raised to 120 ° C. with stirring, and the mixture was further stirred for 30 minutes to completely dissolve the polymer. Thereafter, the p-xylene solution was left at 23 ° C. for 24 hours. The precipitate was separated by filtration, and the p-xylene solution was completely concentrated to obtain a soluble component.

Room temperature p-xylene solubles (%) = (p-xylene solubles (g) / 1 g of polymer) × 100.

(2) Melt flow rate (hereinafter referred to as MFR)
This is based on ASTM D-1238.

(3) Molecular weight distribution (hereinafter abbreviated as Mw / Mn) The weight average molecular weight (Mw) and the number average molecular weight (Mw) were determined by GPC (gel permeation chromatography).
n) was measured and determined. The measurement was performed by Senshu Kagaku SSC
According to -7100, the reaction was carried out at 135 ° C. using o-dichlorobenzene as a solvent.

(4) Flexural Modulus (hereinafter abbreviated as Fm) According to ASTM D790.

(5) Izod impact strength Measured with a notch according to JIS K7203.

Example 1 [Preparation of solid titanium compound] The solid titanium compound was prepared according to the method of Example 1 in JP-A-58-83006. That is, anhydrous magnesium chloride 0.95
g (10 mmol), 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 of phthalic anhydride was added to this solution.
(6.75 mmol) was added and the mixture was further stirred and mixed at 125 ° C. for 1 hour to obtain a homogeneous solution. After cooling to room temperature,
40 ml of titanium tetrachloride (0.36 mol
During l), the entire amount was dropped 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 kept at the same temperature for 2 hours. It was kept under stirring. After completion of the reaction for 2 hours, a solid portion was collected by hot filtration, and the solid portion was resuspended in 200 ml of TiCl ₄ , and then heated again at 110 ° C. for 2 hours. After completion of the reaction, a solid portion was collected again by hot filtration,
Washing was sufficiently performed with decane and hexane until no free titanium compound was detected in the washing solution. The composition of the solid Ti catalyst was 2.1% by weight of titanium, 57% by weight of chlorine, 18.0% by weight of magnesium, and 2 parts of diisobutyl phthalate.
It was 1.9% by weight.

[Preliminary polymerization] 1 liter of N ₂ -substituted
After charging 200 ml of purified hexane, 50 mmol of triethylaluminum, 10 mmol of N, N'-dimethylethylenediaminodimethoxysilane, 50 mmol of ethyl iodide and 5 mmol of solid titanium catalyst component in terms of Ti atom into a toclave, propylene was added to 1 g of solid catalyst component. Introduced into the autoclave continuously for 3 minutes to 3 g. The temperature during this period was kept at 10 ° C. After 30 minutes, the reaction was stopped, and the inside of the autoclave was sufficiently replaced with N ₂ . The solid part of the obtained slurry was washed four times with purified hexane to obtain a titanium-containing polypropylene. As a result of the analysis, 2.1 g of propylene was polymerized per 1 g of the solid titanium catalyst component.

[Main Polymerization] (1) Polymerization of Polypropylene Component 100 kg of propylene was charged into a polymerization tank having an inner volume of 400 l and having been subjected to N ₂ substitution, and triethyl aluminum 150
mmol, N, N'-dimethylethylenediaminodimethoxysilane, 75.0 mmol, and hydrogen gas were charged so that the gas concentration in the gas phase was 2 mol%, and then the internal temperature of the autoclave was raised to 65 ° C. 0.50 mmol of the solid titanium catalyst obtained by the secondary polymerization was charged as Ti atoms. Subsequently, the internal temperature of the autoclave was raised to 70 ° C., and polymerization was performed for 90 minutes. After the completion of the polymerization, unreacted propylene was removed to obtain a white granular polypropylene component. The weight of the polymer obtained at this stage was 30.8 kg. For the obtained polypropylene component, the amount of p-xylene soluble matter was measured.

Table 1 shows the results.

(2) Polymerization of Propylene-Ethylene Copolymer Component 15 kg of the above-mentioned polypropylene component was weighed and transferred to a 440 l internal volume gas-phase polymerization tank with N ₂ substitution. The temperature in the polymerization vessel was raised to 70 ° C., and ethylene and propylene gas were continuously supplied into the polymerization vessel so that the gas concentration in the gas phase became 35/65 (molar ratio). At the same time, hydrogen gas was supplied so that the gas concentration in the gas phase became 0.2 mol%. Polymerization was performed at 70 ° C. for 2 hours. After completion of the polymerization, 50 ml of methanol was added as a polymerization terminator to stop the reaction, and unreacted monomer gas was removed. The yield of the obtained propylene-ethylene block copolymer was 17.6 kg.
That is, the proportion of the propylene-ethylene copolymer component in the total polymer was 15% by weight. Therefore,
The polymerization ratio of all polymers is 32000 g-PP / g-ca
t. The ethylene content in the propylene-ethylene copolymer component is determined by the polymerization rate and the obtained propylene-
It was determined by calculation from the measurement of the ethylene content of the ethylene block copolymer. Next, the obtained polymer of the propylene-ethylene block copolymer was sent to a flash tank and separated from liquid propylene to obtain a white cheek granular polymer. An antioxidant was added to the above polymer, and after sufficient mixing, the mixture was pelletized by a granulator, and the physical properties were evaluated.

Examples 2 to 6 In place of the N, N'-dimethylethylenediaminodimethoxysilane used in the prepolymerization and the main polymerization of Example 1,
N, N′-dimethyl-1,1,2,2-tetramethylethylenediaminodimethoxysilane (Example 2)
N′-diipropylethylenediaminodimethoxysilane (Example 3), N, N′-dimethyl-1,3-propanediaminodimethoxysilane (Example 4), N, N′-dicyclohexylethylenediaminodimethoxysilane (Example) 5) The same operation as in Example 1 was performed except that N, N'-diphenylethylenediaminodimethoxysilane (Example 6) was used. The results are shown in Table 1.

Comparative Examples 1-4 In place of the N, N'-dimethylethylenediaminodimethoxysilane used in the prepolymerization and the main polymerization of Example 1, cyclohexylmethyldimethoxysilane (Comparative Example 1) and diphenyldimethoxysilane (Comparative Example) 2) The same operation as in Example 1 was performed except that tetraethoxysilane (Comparative Example 3) and ethylenediaminodimethoxysilane (Comparative Example 4) were used. The results are shown in Table 1.

Example 7 The same operation as in Example 1 was carried out except that hydrogen gas was charged in the first step of the main polymerization in Example 1 in a gas phase gas concentration of 10 mol%). The results are shown in Table 1. This makes it possible to produce a polymer having a high MFR by controlling the molecular weight with hydrogen.

Comparative Example 5 Dicyclopentyldimethoxysilane was used in place of the N, N'-dimethylethylenediaminodimethoxysilane used in the prepolymerization and the main polymerization of Example 1, and the hydrogen gas concentration was reduced in the first step of the main polymerization. 10mol in gas phase gas concentration
The same operation as in Comparative Example 5 was performed except that% was charged. The results are shown in Table 2. However, 10mo
Due to the difficulty in charging more than 1% of hydrogen gas into the autoclave, it was not possible to produce a polymer having an MFR of more than 25 by polymerization.

Comparative Example 6 When the propylene-ethylene block copolymer obtained in Comparative Example 5 was pelletized by a granulator, an organic peroxide was added as a decomposing agent so that the MFR became 60.
The results are shown in Table 2.

[0080]

[Table 1]

[0081]

[Table 2]

[Brief description of the drawings]

FIG. 1 is a flowchart showing a typical polymerization means of the present invention.

 ──────────────────────────────────────────────────の Continued on front page F-term (reference) 4J026 DA17 DA19 DA20 HA02 HA03 HA04 HA20 HA27 HA35 HA39 HB03 HB04 HB20 HB27 HB35 HB39 HB45 HB48 HE01 4J028 AA01A AB01A AC04A AC05A AC06A AC07A BA00A BA02B BB00B CB00B CB00B CB44A CB56A DA01 DA02 DA03 DA04 EB02 EB04 EC02 FA01 FA02 FA04 FA09 GA05 GA06 GA07 GA21 GA26 GB01

Claims (1)

[Claims] 1. Component [A]: a solid titanium compound [B] component: an organoaluminum compound represented by the general formula [I] R ₃ Al [I] (where R is an alkyl group having 1 to 10 carbon atoms) ) Component [C]: an organosilicon compound represented by the general formula [II] (However, n is an integer of 2 to 6, R ¹ and R ² are hydrogen or a methyl group, and R ³ and R ⁴ are the same or different carbon atoms.
An alkyl group having 1 to 4 carbon atoms, a cyclic alkyl group having 3 to 6 carbon atoms or an aryl group, and R ⁵ is an alkyl group having 1 to 3 carbon atoms. ) In the presence of an olefin polymerization catalyst represented by
In the first step of polymerization, the polymerization of propylene alone or propylene with an α-olefin
0 to 90% by weight, and then, in the second step of the polymerization, the polymerization of propylene and ethylene is performed in an amount of 10 to 5% of the total polymerization amount.
A method for producing a propylene-ethylene block copolymer, which is carried out so as to be 0% by weight.