JP3443849B2 - Method for producing propylene block copolymer - Google Patents

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a propylene block copolymerization method. Specifically, it is a method for producing a propylene block copolymer in which the powder properties of the block copolymer are improved by a combination of a highly active catalyst and a polymerization method, and the physical property balance such as rigidity and impact resistance is improved.

[0002]

2. Description of the Related Art Polypropylene has been in great demand in recent years due to its excellent physical properties. Combined with this increase in demand, the polypropylene production technology has made remarkable progress. As for the polymerization catalyst, compared with the conventional titanium trichloride-type catalyst,
A highly active catalyst in which a titanium compound is supported on a magnesium compound has been developed, and a more streamlined bulk polymerization method or gas phase polymerization method is being adopted for the process.

Further, crystalline polypropylene is drawing attention as a general-purpose resin having excellent rigidity and heat resistance.

However, crystalline polypropylene is
Due to its drawback of being brittle at low temperatures, it was not used in applications requiring impact resistance at low temperatures.

In order to improve this point, various studies have been made and an improved method has been proposed. Among them, industrially useful methods include Japanese Patent Publication No. 38-14834 and Japanese Patent Publication No. 39-1.
No. 836, Japanese Patent Publication No. 39-15535, etc. are proposed, which is a method of block copolymerizing propylene with other olefins, especially ethylene.

However, in these known methods, a method of producing a block polymer through a plurality of steps has been proposed, and various physical properties such as balance between rigidity and impact resistance and appearance of a product are not sufficient.

Japanese Unexamined Patent Publication (Kokai) No. 56-139520 has a step of suspension-polymerizing propylene and a step of copolymerizing propylene with other α-olefins, and specifies an organoaluminum compound catalyst component and an electron donor catalyst component. Has been proposed. Also, JP-A-62-11
In Japanese Patent No. 6618, a method is proposed in which a titanium-containing solid catalyst component (A) is combined with an organoaluminum compound, an inert solvent or propylene is used as a solvent, and three or more polymerization tanks are connected to carry out multistage polymerization. .

None of these processes disclose carrying out the total polymerization as a gas phase polymerization. High rigidity,
In order to obtain a block copolymer having a high impact strength, it is necessary to produce a highly crystalline polymer in the propylene polymerization step. To achieve this end, suspension polymerization is advantageous, as described in these patents. That is, it is easy to achieve high crystallinity by extracting low crystalline components into a solvent. However, in terms of process, it is inevitable that it becomes complicated.

[0009]

SUMMARY OF THE INVENTION An object of the present invention is to provide a method for producing a propylene block copolymer having high rigidity and excellent impact resistance.

[0010]

Means for Solving the Problems As a result of intensive investigations by the present inventors to solve the problems of the prior art,
When carrying out block copolymerization of propylene using a highly active catalyst in which a titanium compound is supported on metallic magnesium , three polymerization steps are combined to synthesize crystalline polypropylene in step (I) and step (II). In the step (III), it was found that a propylene block copolymer having high rigidity and excellent impact resistance can be produced by synthesizing a copolymer of propylene and another olefin by a gas phase method, and the present invention is completed. Came to.

That is, according to the present invention, as the component (A), a catalyst component essentially containing metallic magnesium and a titanium compound, and as the component (B), Ia, IIa, IIb, I of the periodic table.
Selected from organometallic compounds of Group IIb and IVb metals
In the presence of a catalyst composed of at least one compound and an electron-donating compound as the component (C), in the block copolymerization of propylene, in the step (I), a propylene polymer is produced, and the step (II) In, a copolymer having a reaction ratio of propylene alone or other α-olefin and propylene of 10/90 or less in weight ratio is produced, and the copolymer obtained by the step (I) and the step (II). 60% of total polymer
The polymer (H) obtained in the step (I) and the polymer (L) obtained in the step (II) have MFRs of Log (MFR (L) / MFR (H)). ) ≧ 1 and the copolymerization ratio in which the reaction ratio of the other α-olefin and propylene is 30/70 or more by weight in the step (III) is 5 to 40% by weight of the total polymer. As described above, the present invention relates to a method for producing a block copolymer, which comprises carrying out continuous multistage polymerization by a gas phase method.

The catalyst component (A) used in the present invention is gold.
There is no particular limitation as long as it is composed of a magnesium compound and a titanium compound. As an example of a catalyst, JP-A-63
-3007, JP-A-63-314210, JP-A-6
3-317502, JP-A-64-105, JP-A-1
Preparation by the method described in each publication of 165,608 and preparation by the following method are possible.

A uniform solution obtained by reacting (i) metallic magnesium and an organic hydroxide compound, (ii) an oxygen-containing organic compound of aluminum and (iii) an oxygen-containing organic compound of titanium such as an alkoxide of titanium, iv) It can be obtained by reacting a solid product obtained by reacting aluminum halide with (v) an electron donating compound and (vi) a titanium halide compound.

When metal magnesium and an organic hydroxide compound are used in the above (i), various forms of metal magnesium can be used, that is, powder, particles, foil, ribbon, or any other form can be used. Suitable compounds are alcohols, phenols and organic silanols.

As the alcohols, straight-chain or branched-chain aliphatic alcohols having 1 to 18 carbon atoms, alicyclic alcohols or aromatic alcohols can be used.

Examples include methanol, ethanol, n
-Propanol, i-Propanol, n-Butanol,
n-hexanol, 2-ethylhexanol, n-octanol, i-octanol, n-stearyl alcohol
And cyclopentanol, cyclohexanol, ethylene glycol and the like. Further, examples of the phenols include phenol, cresol, xylenol and hydroquinone.

The organic silanol has at least one hydroxyl group, and the organic group has an alkyl group having 1 to 12 carbon atoms, preferably 1 to 6 carbon atoms, a cycloalkyl group, It is selected from compounds having an arylalkyl group, an aryl group, and an alkylaryl group.

Examples include trimethylsilanol, triethylsilanol, triphenylsilanol, t-butyldimethylsilanol and the like.

These hydroxylated organic compounds are used alone or as a mixture of two or more kinds.

In addition, when using magnesium metal to obtain the solid catalyst component of component (A) described in the present invention, it reacts with magnesium metal or produces an addition compound for the purpose of promoting the reaction. It is desirable to add such a substance, for example, a polar substance such as iodine, mercuric chloride, an alkyl halide and an organic acid, either alone or in combination of two or more.

[0021]

As the oxygen-containing organic compound of aluminum, which is the reactant of (ii), an oxygen-containing organic compound represented by the general formula Al (OR ¹ ) _m X _3-m is used. However,
In the general formula, R ¹ represents a hydrocarbon group having 1 to 20 carbon atoms, preferably 1 to 10 carbon atoms. Examples of such a hydrocarbon group include a straight chain or branched chain alkyl group, a cycloalkyl group, an arylalkyl group, an aryl group and an alkylaryl group. m represents a number satisfying 0 <m ≦ 3, and X represents a halogen atom.

Specific examples of oxygen-containing organic compounds of aluminum include trimethoxyaluminum, triethoxyaluminum, tri-n-propoxyaluminum, tri-i-propoxyaluminum, tri-n-butoxyaluminum and tri-sec-butoxyaluminum. ，
Tri-tert-butoxyaluminum, tri (2-ethylhexoxy) aluminum, triphenoxyaluminum, tribenzyloxyaluminum, dichloromethoxyaluminum, chlorodimethoxyaluminum,
Examples thereof include dichloro (2-ethylhexoxy) aluminum, chlorodi (2-ethylhexoxy) aluminum, dichlorophenoxyaluminum and chlorodiphenoxyaluminum. The use of oxygen-containing organic compounds of aluminum having several different hydrocarbon groups is also within the scope of the invention. These oxygen-containing organic compounds of aluminum are used alone or as a mixture of two or more kinds. As the oxygen-containing organic compound of titanium which is the reactant of (iii), a compound represented by the general formula [O _p Ti _u (OR ² ) _q ] _n is used. However, in the general formula, R ² represents a hydrocarbon group having 1 to 20 carbon atoms, preferably 1 to 10 carbon atoms.

Examples of such a hydrocarbon group include a straight chain or branched chain alkyl group, a cycloalkyl group, an arylalkyl group, an aryl group and an alkylaryl group. p, q and u are p ≧ 0, q> 0,
When u ≧ 1, it represents a number compatible with the valence of Ti, and n represents an integer. Above all, 0 ≦ p ≦ 1, 1 ≦ u ≦ 2, 1 ≦ n
It is desirable to use oxygen containing organic compounds of titanium such that ≦ 6.

Specific examples include titanium tetramethoxide, titanium tetraethoxide, titanium tetra-n-propoxide, titanium tetra-i-propoxide, titanium tetra-n-butoxide, titanium tetra-i-butoxide and tetra ( n-nonyl) titanate, tetra (2-ethylhexyl) titanate, tetracresyl titanate
And hexa-i-propoxydititanate. The use of oxygen containing organic compounds of titanium having several different hydrocarbon groups is also within the scope of the present invention. These oxygen-containing organic compounds of titanium may be used alone,
It is also possible to use them after mixing or reacting two or more kinds.

As the aluminum halide compound which is the above-mentioned (iv) reactant, those represented by the general formula AlR ³ _r X _3-r are used. In the formula, R ³ represents a hydrocarbon group having 1 to 20 carbon atoms, X represents a halogen atom, and r represents a number satisfying 0 <r ≦ 2. R ³ is preferably selected from linear or branched alkyl groups, alkoxy groups, cycloalkyl groups, arylalkyl groups, aryl groups and alkylaryl groups. The above aluminum halide compounds are used alone or as a mixture of two or more kinds.

Specific examples of aluminum halides include, for example, ethyl aluminum dichloride, n-propyl aluminum dichloride, n-butyl aluminum dichloride, i-butyl aluminum dichloride, sesquiethyl aluminum chloride, sesqui-i.
-Butyl aluminum chloride, sesqui-i-propyl aluminum chloride, sesqui-n-propyl aluminum chloride, diethyl aluminum chloride, di-i-propyl aluminum chloride, di-n
-Propyl aluminum chloride, di-i-butyl aluminum chloride, diethyl aluminum bromide, diethyl aluminum iodide and the like.

The electron-donating compound which is the above-mentioned (v) reactant is an ether, an ester, a ketone or a phenol.
, Amine, amide, imine, nitrile, phosphine,
Mention may be made of phosphites, stibines, arsines, phosphorylamides and alcoholates. Of these, esters are preferred, and organic acid esters are most preferred.

Examples of organic acid esters include mono- or diesters of aromatic carvone and mono- or diesters of aliphatic carboxylic acid.

Specific examples thereof include butyl formate, ethyl acetate, butyl acetate, isobutyl isobutyrate, propyl pivalate, isobutyl pivalate, ethyl acrylate, methyl methacrylate, ethyl methacrylate, isobutyl methacrylate, malonic acid. Diethyl, diisobutyl malonate, diethyl succinate, dibutyl succinate, diisobutyl succinate, diethyl glutarate, dibutyl glutarate, diisobutyl glutarate, diisobutyl adipate, dibutyl sebacate, diethyl maleate, dibutyl maleate, diisobutyl maleate, Monomethyl fumarate, diethyl fumarate, diisobutyl fumarate, diethyl tartrate, dibutyl tartrate, diisobutyl tartrate, methyl benzoate, ethyl benzoate, methyl p-toluate, p-toluy Ethyl, p-tert-butyl benzoate, ethyl p- anisic acid, alpha-naphthoic acid isobutyl, ethyl cinnamate, monomethyl phthalate,
Dibutyl phthalate, diisobutyl phthalate, dihexyl phthalate, dioctyl phthalate, di2-ethylhexyl phthalate, diallyl phthalate, diphenyl phthalate, diethyl isophthalate, diisobutyl isophthalate, diethyl terephthalate, dibutyl terephthalate, diethyl naphthalate. , Dibutyl naphthalate and the like. The electron donating compound (v) is used alone or as a mixture of two or more kinds.

As the titanium halide compound which is the reactant of (vi), a titanium compound represented by the general formula Ti (OR ⁴ ) _f X _4-f is used. In the formula, R ⁴ is 1
Represents a hydrocarbon group having 20 carbon atoms, X represents a halogen atom, and f represents a number 0 ≦ f <4. R ⁴
Is preferably selected from linear or branched alkyl groups, alkoxy groups, cycloalkyl groups, arylalkyl groups, aryl groups and alkylaryl groups. The titanium halide compound may be used alone or as a mixture of two or more kinds.

Specific examples of the titanium halide compound include titanium tetrachloride, ethoxy titanium trichloride, propoxy titanium trichloride, butoxy titanium trichloride, phenoxy titanium trichloride, diethoxy titanium dichloride, triethoxy titanium chloride and the like. Is mentioned.

The solid catalyst component obtained in the present invention was obtained by reacting the homogeneous solution obtained by reacting the above-mentioned reaction agents (i), (ii) and (iii) with the reaction agent (iv). It can be prepared by reacting the solid product with the reactants (v) and (vi).

These reactions are preferably carried out in a liquid medium. Therefore, it should be carried out in the presence of an inert organic solvent, especially if these reactants themselves are not liquid under the operating conditions or if the amount of liquid reactant is insufficient.
As the inert organic solvent, any of those commonly used in the art can be used, and examples thereof include aliphatic, alicyclic or aromatic hydrocarbons, halogen derivatives thereof, or a mixture thereof.

For example, isobutane, pentane, isopentane, hexane, heptane, cyclohexane, benzene,
Toluene, xylene, chlorobenzene, 1,2-dichlorobenzene, 1,3-dichlorobenzene, benzyl chloride, methylene dichloride, 1,2-dichloroethane, 1,3
-Dichloropropane, 1,4-dichlorobutane, 1,
1,1, -trichloroethane, 1,1,2-trichloroethane, 1,1,1,2-tetrachloroethane, 1,
1,2,2-tetrachloroethane, tetrachloroethylene, carbon tetrachloride, chloroform and the like can be mentioned.

Even if these organic solvents are used alone,
You may use it as a mixture. Incidentally, when a halogen derivative or a mixture thereof is used, good results may be obtained in polymerization activity and stereoregularity of the polymer.

Reactants (i), (i used in the present invention
The amount of i), (iii), (iv), (v), (vi) used is not particularly limited, but the molar ratio of the magnesium atom (i) to the oxygen-containing organic compound (ii) of aluminum is
If it is intended to obtain polymer particles having a pellet size of 1: 0.01 to 1:20, especially 3000 μm or more, it is desirable to select the range of 1: 0.05 to 1:10.

The molar ratio of magnesium atom (i) to oxygen-containing organic compound of titanium (iii) is 1: 0.01.
It is preferable to select the amount used to be 1: 0.1 to 1: 5, preferably 1: 0.1 to 1: 5 in order to obtain pellet-sized polymer particles having extremely good powder characteristics.

The ratio of magnesium atoms to aluminum atoms in aluminum halide (iv) is 1:
0.1 to 1: 100, preferably 1: 0.1 to 1:20
It is preferable to select the amount of the reactant used so as to fall within the range. If the ratio of aluminum atoms is out of this range and is too large, the catalytic activity may be lowered, or good powder properties may not be obtained. If it is too small, good powder properties may not be obtained.

The magnesium atom (i) and the electron-donating compound (v) are used in a molar ratio of 1: 0.05 to 1: 5.0, preferably 1: 0.1 to 1: 2.0. It is preferable to choose the amount. Outside of these ranges, problems such as low polymerization activity and low stereoregularity of the polymer may occur. Further, the molar ratio of the magnesium atom (i) and the titanium halide compound (vi) is
It is preferable to select the amount of the reactant used so as to be in the range of 1: 1 to 1: 100, preferably 1: 3 to 1:50.
If the amount is out of this range, problems such as low polymerization activity and coloring of the product may occur.

The reaction conditions for obtaining a homogeneous solution from the reactants (i), (ii) and (iii) are -50 to 300 ° C, preferably 0 to 200 ° C, and 0.5 to 50 ° C.
It is carried out at normal pressure or under pressure in an inert gas atmosphere for a time, preferably 1 to 6 hours. Further, at this time, by adding an electron donating compound similar to the compound (v), homogenization can be performed in a shorter time.

Further, the reactants (iv), (v), (v
In the reaction of i), -50 to 200 ° C, preferably-
0.2 to 50 hours at a temperature of 30 to 150 ° C.
It is preferably carried out for 0.5 to 10 hours in an inert gas atmosphere at normal pressure or under pressure.

The reaction conditions of the reactant (iv) are important,
It is extremely important because it plays a decisive role in controlling the particle shape and particle size of the solid product particles produced, the solid catalyst component particles, and the polymer particles obtained using them.

The reaction of the reaction agent (vi) may be carried out by dividing it in multiple stages. Furthermore, the reaction of reactants (vi), in the general formula R-CH = CH ₂ (wherein, R 1-10, in particular a substituted or non-substituted straight or branched chain having 1 to 8 carbon atoms Ethylene and / or α represented by an alkyl group or a hydrogen atom)
-It may be carried out in the presence of an olefin. In these cases, effects such as improvement in polymerization activity and stereoregularity of the polymer may be recognized as a result.

Thus obtained solid catalyst component (A)
May be used as it is, but generally, the unreacted substances and by-products that remain are removed by filtration or a decantation method, and after sufficient washing with an inert organic solvent, the product is suspended in an inert organic solvent. To use. It is also possible to use a product which is isolated after washing and heated under normal pressure or reduced pressure to remove the inert organic solvent.

Examples of the organometallic compound as the component (B) include Ia, IIa, IIb, IIIb and IVb of the periodic table.
At least one selected from the group consisting of organometallic compounds of group metals, and examples thereof include organometallic compounds composed of a metal such as lithium, magnesium, zinc, tin or aluminum and an organic group.

As the above-mentioned organic group, an alkyl group can be mentioned as a representative. As this alkyl group,
A linear or branched alkyl group having 1 to 20 carbon atoms is used. Specifically, for example, n-butyl lithium, diethyl magnesium, triethyl aluminum, tri-
i-Butyl aluminum, diethyl aluminum chloride, diisobutyl aluminum chloride, etc. can be used.

As the electron donating compound of the component (C),
Organic acid esters, oxygen-containing organic compounds of silicon, nitrogen-containing organic compounds and the like are preferable.

Examples of organic acid esters include mono- or diesters of aromatic carboxylic acids and mono- or diesters of aliphatic carboxylic acids. Of these, aliphatic carboxylic acid esters and aromatic carboxylic acid esters are preferred. Specific examples of the aliphatic carboxylic acid ester include ethyl acetate, propyl acetate, butyl acetate, ethyl propionate, butyl propionate, and ethyl butyrate having 2 to 18 carbon atoms. The aromatic carboxylic acid ester has 1 to 2 carbon atoms.
Examples of the compound having 4 are methyl benzoate, ethyl benzoate, methyl toluate, ethyl toluate, methyl anisate and ethyl anisate. The above organic acid esters may be used alone, or may be used by mixing or reacting two or more kinds.

As the oxygen-containing organic compound of silicon, an oxygen-containing organic compound of silicon represented by the general formula R ⁵ _s Si (OR ⁶ ) _t X _{4- (s + t)} is used.
However, in the general formula, R ⁵ and R ⁶ have 1 to 2 carbon atoms.
0, preferably 1-10 hydrocarbon groups or hydrogen atoms such as linear or branched alkyl groups, cycloalkyl groups, arylalkyl groups, aryl groups and alkylaryl groups, where s and t are 0 ≦ s ≦ 3, 1 ≦ t ≦ 4,
1 ≦ s + t ≦ 4, and X represents a halogen atom.

As a specific example, tetramethoxysilane,
Tetraethoxysilane, tetra-n-propoxysilane, tetra-i-propoxysilane, tetra-n-butoxysilane, tetra-i-pentoxysilane, tetra-
n-hexoxysilane, tetraphenoxysilane, tetrakis (2-ethylhexoxy) silane, tetrakis (2-ethylbutoxy) silane, tetrakis (2-methoxyethoxy) silane, methyltrimethoxysilane, ethyltrimethoxysilane, n-propyltrimethoxysilane , I-propyltrimethoxysilane, n-butyltrimethoxysilane, i-butyltrimethoxysilane, s
ec-butyltrimethoxysilane, t-butyltrimethoxysilane, phenyltrimethoxysilane, vinyltrimethoxysilane, norbonyltrimethoxysilane, cyclohexyltrimethoxysilane, chloromethyltrimethoxysilane, 3-chloropropyltrimethoxysilane,
4-chlorotrimethoxysilane, triethoxysilane,
Methyltriethoxysilane, ethyltriethoxysilane, n-propyltriethoxysilane, n-butyltriethoxysilane, phenyltriethoxysilane, vinyltriethoxysilane, 3-aminopropyltriethoxysilane, ethyltri-i-propoxysilane, i -Pentyltri-n-butoxysilane, methyltri-n-hexoxysilane, methyldimethoxysilane, dimethyldimethoxysilane, n-propylmethyldimethoxysilane,
n-propylethyldimethoxysilane, di-n-propyldimethoxysilane, i-propylmethyldimethoxysilane, di-i-propyldimethoxysilane, n-propyl-i-propyldimethoxysilane, n-butylmethyldimethoxysilane, n-butyl Ethyldimethoxysilane, n-butyl-n-propyldimethoxysilane, n-
Butyl-i-propyldimethoxysilane, di-n-butyldimethoxysilane, i-butylmethyldimethoxysilane, di-i-butyldimethoxysilane, sec-butylethyldimethoxysilane, di-sec-butyldimethoxysilane, tert-butylmethyl Dimethoxysilane,
tert-butyl-n-propyldimethoxysilane, di-tert-butyldimethoxysilane, tert-butyl-n-hexyldimethoxysilane, diisoamyldimethoxysilane, n-hexyl-n-propyldimethoxysilane, n-decylmethyldimethoxysilane, Norbonylmethyldimethoxysilane, cyclohexylmethyldimethoxysilane, methylphenyldimethoxysilane, diphenyldimethoxysilane, dicyclopentyldimethoxysilane, dimethyldiethoxysilane, diethyldiethoxysilane, di-i-propyldiethoxysilane, sec
-Butylmethyldiethoxysilane, tert-butylmethyldiethoxysilane, dimethyldi-n-butoxysilane, trimethylmethoxysilane, trimethylethoxysilane, trimethyl-i-propoxysilane, trimethyl-n-propoxysilane, trimethyl-tert-butoxysilane Alkoxysilanes such as trimethyl-i-butoxysilane, trimethyl-n-butoxysilane, trimethyl-n-pentoxysilane and trimethylphenoxysilane, or aryloxysilanes, dichlorodiethoxysilane, dichlorodiphenoxysilane, tribromoethoxysilane, etc. Haloalkoxysilane or haloallyloxysilane. The above oxygen-containing organic compounds of silicon may be used alone, or two or more kinds may be mixed or reacted and used.

Examples of the nitrogen-containing organic compound include compounds having a nitrogen atom in the molecule and having a function as a Lewis base. Specifically, amide compounds such as acetic acid N, N-dimethylamide, benzoic acid N, N-dimethylamide, toluic acid N, N-dimethylamide, 2,
2,6,6-tetramethylpiperidine, 2,6-diisopropylpiperidine, 2,6-diisobutylpiperidine, 2,6-diisobutyl-4-methylpiperidine,
2,2,6-trimethylpiperidine, 2,2,6,6-
Tetraethylpiperidine, 1,2,2,6,6-pentamethylpiperidine, 2,2,6,6-tetramethyl-4
-Piperidyl benzoate, piperidine-based compounds such as bis (2,2,6,6-tetramethyl-4-piperidyl) sebacate, 2,6-diisopropylpyridine, 2,
Pyridine compounds such as 6-diisobutylpyridine and 2-isopropyl-6-methylpyridine, 2,2,5,5
-Tetramethylpyrrolidine, 2,5-diisopropylpyrrolidine, 2,2,5-trimethylpyrrolidine, 1,
Pyrrolidine compounds such as 2,2,5,5-pentamethylpyrrolidine and 2,5-diisobutylpyrrolidine, trimethylamine, triethylamine, tributylamine,
Tribenzylamine, tetramethylethylenediamine,
Amine-based compounds such as diisopropylethylamine, tert-butyldimethylamine, diphenylamine, di-o-tolylamine, N, N-diethylaniline, N,
Examples thereof include aniline-based compounds such as N-diisopropylaniline. The above nitrogen-containing organic compounds may be used alone, or may be used by mixing or reacting two or more kinds.

These electron donating compounds may be used in combination.

The amount of the organometallic compound as the component (B) used is
The molar ratio of organometallic compound / Ti in the catalyst component (A) is preferably in the range of 0.1 to 1000.

The electron donating compound as the component (C) has a molar ratio of electron donating compound / organometallic compound of 0.001 to 1
It is preferably used in the range of 0.

The mode of feeding the catalyst component into the polymerization vessel in the present invention is not particularly limited, and for example, the catalyst components (A), (B) and (C) can be fed separately into the polymerization vessel. Or a method of bringing the catalyst components (A) and (C) into contact with each other and then bringing them into contact with the component (B) to polymerize,
A method of contacting the component (B) and the component (C) and then contacting the catalyst component (A) for polymerization, or a method of contacting the catalyst components (A) and (B) and the component (C) in advance for polymerization. A method etc. can be adopted.

The reactor used in the polymerization step can be appropriately used if it is one usually used in the art. For example, the polymerization operation can be carried out in any of a continuous system, a semi-batch system and a batch system by using a stirred tank reactor, a fluidized bed reactor or a circulation reactor.

The polymerization of the present invention is preferably carried out by gas phase polymerization at a reaction temperature below the melting point of the polymer and at a pressure of ^{2 to} 50 kg / cm ² · G. Either polymerization or suspension polymerization can be adopted.

The adjustment of the molecular weight in each step is generally performed by a molecular weight regulator (for example, hydrogen). Process (II)
And in the step (III), it is preferable to control the molecular weight with hydrogen. However, in the case where the molecular weight is adjusted by the hydrogen concentration, if the hydrogen concentration in the preceding stage is higher than that in the latter stage, it is necessary to provide a hydrogen purging step between both stages.

Prior to the main polymerization, the general formula R ⁷ —CH═CH ₂ (wherein R ⁷ is a linear or branched, substituted or unsubstituted chain having 1 to 10 carbon atoms, particularly 1 to 8 carbon atoms). It can also be used after pre-polymerizing an α-olefin represented by (representing an alkyl group) and / or ethylene. In the preliminary polymerization, after preparing the catalyst component (A), the component (B) and the component (C) are prepared.
In the presence of a batch reactor. Alternatively, before the step (I), a prepolymerization reactor may be provided and continuously carried out. Either bulk polymerization or suspension polymerization can be adopted, but the preliminary polymerization is preferably carried out at a temperature of 50 ° C. or lower.

In the present invention, the α-olefin which is block-copolymerized with propylene is represented by the general formula R ⁸ —CH═CH ₂ (wherein R ⁸ has 1 to 20 carbon atoms, particularly 1 to 8 carbon atoms). Α-olefin represented by a chain or branched chain substituted / unsubstituted alkyl group) is preferable, and two or more kinds of them can be used in combination.

It is carried out so that the proportion of the copolymer obtained in step (I) and step (II) is 60 to 95% by weight, preferably 70 to 90% by weight, based on the total polymer. If the proportion of the copolymer obtained in the steps (I) and (II) is lower than 60% by weight, the rigidity of the final copolymer becomes too low, and if it exceeds 95% by weight, the impact strength becomes insufficient, which is not preferable.

M of polypropylene produced in step (I)
FR (hereinafter referred to as MFR (H)) is 0.03 to 50
It is preferably 0. In step (II), the reaction ratio of the other α-olefin and propylene is 10/90 or less by weight, preferably 5/95 or less. When the reaction ratio of other α-olefin and propylene exceeds 10/90, the rigidity of the final copolymer becomes insufficient, which is not preferable. The MFR of the polymer produced in the step (II) (hereinafter referred to as MFR (L)) is preferably 0.05 to 1000. Further, the relationship between MFR (H) and MFR (L) is such that Log (MFR (L) / MFR (H)) ≧ 1 and preferably Log (MFR (L) / MFR (H)) ≧ 1.2. There is a need to. If MFR (H) and MFR (L) are out of this range, a desired highly rigid propylene block copolymer cannot be obtained.

In step (III), the copolymerization ratio at which the reaction ratio of other α-olefin and propylene is 30/70 or more, preferably 35/65 or more by weight, is 5 to 40% by weight of the total polymer. And preferably 10 to 35%. If the reaction ratio of α-olefin and propylene is out of the predetermined range, the rigidity and impact resistance at room temperature are insufficient, which is not preferable. M in step (III)
It is preferable to produce a copolymer having an FR of 0.001 to 100.

According to the above method, the object of the present invention can be sufficiently achieved. However, in order to obtain a polymer having more excellent homogeneity, the polymer (H) obtained in the step (I) and the polymer (L) obtained in the step (II)
It is preferable that the polymerization ratio of H / L ≧ 1.

Step (I), Step (II) and Step (I
II) may be carried out by multi-stage polymerization of two or more steps.

[0067]

By using the method of the present invention, polypropylene having very good rigidity and impact resistance can be obtained as compared with conventional general propylene block copolymers. That is,
By carrying out block copolymerization of propylene, which comprises a titanium compound supported on a magnesium compound and comprises steps (I), (II) and (III), a propylene block copolymer having high rigidity and excellent impact resistance is obtained. Coalescence is easily obtained.

[0068]

EXAMPLES The present invention will be shown below with reference to examples, but the present invention is not limited to these examples.

The properties of polymers in Examples and Comparative Examples were measured by the following methods. MFR: ASTM D-1238 Ethylene content of melt index polymer according to condition E: Measured by infrared absorption spectrum (FT-IR5M type, JASCO Corporation) Bending rigidity: JIS-K7203 Izod impact strength: JIS-K7110 Uniformity : A cast film was formed and fish eyes were observed.

The physical properties were measured by adding known additives such as antioxidants to the obtained polymer particles, melt granulating with a 50 mm extruder, and molding with a Toshiba IS-100E injection molding machine. It evaluated using the piece.

Reference Example 1 (a) [Preparation of catalyst component (A)] To a 20 l autoclave equipped with a stirrer, 120 g (4.9 mol) of magnesium metal powder was placed, and 6 g of iodine, 1450 g (19.6 g) of n-butyl alcohol
Mol), 1680 g (4.9 mol) of titanium tetrabutoxide and 470 g (1.72 mol) of diisobutyl phthalate were added to give tri-i-propoxyaluminum 992.
After adding g (4.9 mol) and further adding 5 liters of decane, the temperature was raised to 90 ° C., and the mixture was stirred for 1 hour under a nitrogen seal while eliminating generated hydrogen gas. Subsequently, the temperature was raised to 140 ° C. and the reaction was performed for 2 hours to obtain a uniform solution (Mg—Ti solution) containing magnesium and titanium.

After being rapidly cooled to 0 ° C., 2294 g (7.4 mol) of i-butylaluminum dichloride was added to 5% with hexane.
The solution diluted to 0% was added over 2 hours. After all the ingredients were added, the temperature was raised to 70 ° C. over 2 hours to obtain a slurry containing a white solid product. The solid product was separated by filtration and washed with hexane.

5.2 l of titanium tetrachloride was added to 5.2 g of chlorobenzene in the slurry containing the white solid product thus obtained.
The total amount of the solution diluted with 1 was added, then 670 g of diisobutyl phthalate was added, and the mixture was reacted at 100 ° C. for 3 hours. The solid portion was collected by filtering the product, and a solution prepared by diluting 5.2 l of titanium tetrachloride with 5.2 l of chlorobenzene was added again, and the mixture was stirred at 100 ° C. for 2 hours. Hexane was added to this product, and washing operation was sufficiently performed until no liberated titanium compound was detected to obtain a slurry of the catalyst component (A) suspended in hexane. A part of the solution was taken out, the supernatant was removed, the product was dried under a nitrogen atmosphere, and elemental analysis revealed that Ti was 3.0% by weight.

(B) Prepolymerization of the catalyst component (A) 100 g of the catalyst component (A) obtained by the method (a) above was thoroughly substituted with nitrogen in the 20 liter autoclave.
Triethylaluminum 6 as organometallic compound (B)
27 mmol, 160 mmol of diphenyldimethoxysilane as an electron-donating compound (C) were sequentially added, and 6 l of hexane was added. Autoclave internal pressure 0.1kg /
After adjusting the internal temperature to 10 ° C. in cm ² G, 200 g of propylene was supplied for 20 minutes while maintaining the temperature at 10 ° C., and the mixture was stirred for 30 minutes. The catalyst component (A) thus obtained was separated by filtration and washed sufficiently with hexane to obtain a slurry of the prepolymerized catalyst suspended in hexane. The yield after the supernatant was removed and dried under a nitrogen atmosphere was 300 g.

Example 1 Gas phase continuous polymerization was carried out by connecting three fluidized bed type polymerization vessels each having an internal volume of 3 m ³ in series. In the first polymerization vessel, 6 g / hour of the prepolymerization catalyst component obtained in Reference Example 1 and triethylaluminum as the component (B) were added Al / T to Ti in the catalyst.
Diphenyldimethoxysilane was used as the component (C) so that i = 50 mol / mol, and Si / Al = 0.5 mol / mol.
It was fed continuously so as to have a mole. Further, propylene and hydrogen were continuously fed so that the propylene partial pressure was 14.8 kg / cm ² , and the hydrogen was 0.00016 mol / mol with respect to propylene. Polymerization was carried out. (Step I) The polymerized polymer particles were discharged into a discharge tank and then transferred to a second polymerization vessel.

In the second polymerization vessel, the propylene partial pressure was 13.
1 kg / cm ² , hydrogen was continuously fed to ethylene at 0.097 mol / mol, and 80 ° C
Polymerization of propylene was carried out. (Step II) The polymerized polymer particles were discharged into a discharge tank and then transferred to a third polymerization vessel.

A propylene partial pressure of 4.4 was applied to the third polymerization vessel.
kg / cm ^2, 0 hydrogen and ethylene to propylene.
Copolymerization of propylene and ethylene was carried out at 70 ° C. by continuously feeding each at a rate of 0083 mol / mol and 0.29 mol / mol. (Step III) Each polymerization condition is shown in Table 1.

The residence time in each polymerization vessel was 2 hours, and 20 kg of the polymer was withdrawn from the third polymerization vessel per hour.

When a small amount of the polymer discharged from each polymerizer was extracted, the MFR of the polymer in the first polymerizer was 0.
22, the xylene solubles Xy was 1.4%, the MFR of the polymer of the second polymerization vessel was 0.8, and the polymer of the third polymerization vessel was
Had an ethylene content of 7.8%. Moreover, since the polymerization rate of each polymerization vessel is 44%, 41%, and 15%,
The ethylene content in the component produced in the third polymerization vessel was 52% by weight.

This copolymer was added to Irganox-101.
0, Irgafos-168, and calcium stearate were each mixed at 1000 ppm and granulated with a 50 mm uniaxial extruder. The MFR was 0.43. The granulated copolymer was molded with a Toshiba IS-100E injection molding machine, and the physical properties were evaluated. The results are shown in Table 2.

Comparative Examples 1 and 2 The same prepolymerized catalyst component (A) as in Example 1,
Although multi-stage polymerization was carried out using the components (B) and (C), the step (II) was omitted in Comparative Example 1. Polymerization was carried out in the same manner as in Example 1 except that the polymerization conditions were changed as shown in Table 1. The results are shown in Table 2.

Examples 2 to 5 Polymerization was carried out in the same manner as in Example 1 except that the polymerization conditions were changed as shown in Table 1. The results are shown in Table 2.

Example 6 A continuous gas phase polymerization was carried out by connecting in series a reactor equipped with a stirrer with an internal volume of 100 ml, one prepolymerizer with an internal volume of 5 l and ^three fluidized bed type polymerizers with a volume of 3 m ³ .

The slurry of the catalyst component (A) obtained in Reference Example (a) was placed in a reactor having an internal volume of 100 ml in which stirring was started.
(2.0 g / hr as the catalyst component (A)) and triethylaluminum diluted to 20% with hexane as the component (B) relative to Ti in the catalyst Al / Ti = 50
The supply was started so as to be mol / mol, and the reactor was filled with liquid while degassing from the degassing port at the top of the reactor. After confirming the full state of the reactor, the degassing port was closed and the catalyst component (A) and the component (B) were continuously added at the same ratio while maintaining the internal pressure at 40 kg / cm ² and the internal temperature at 25 ° C. Supplied.

Liquid propylene was supplied at a rate of 24 kg / hour to a reactor having an internal volume of 5 l, and the reactor was filled with liquid while degassing from the degassing port at the top of the reactor. After confirming the full state of the reactor, the degassing port was closed and stirring was started. Internal pressure is 35 kg / cm ² and internal temperature is 25 ° C.
Liquid propylene, keeping the above, the above internal volume 100ml
Of the catalyst component (A) and the component (B) in an amount commensurate with the amount supplied to the reactor from the reactor, and diphenyldimethoxysilane as the component (C) so that Si / Al = 0.5 mol / mol. To form a prepolymerized catalyst. When the prepolymerization catalyst was extracted and the Ti residue was analyzed, it was found that 100 g of propylene was reacted per 1 g of the catalyst component (A).

The propylene slurry of the above-mentioned prepolymerization catalyst was continuously fed to the first polymerization vessel. Liquid propylene is vaporized, but propylene is continuously replenished so that the partial pressure of propylene is 16.0 kg / cm ² , and hydrogen is adjusted to 0.0012 mol / mol with respect to propylene to obtain a polymerization temperature of 80. Polymerization of propylene was performed at ℃. (Step I) The polymerized polymer particles were discharged into a discharge tank and then transferred to a second polymerization vessel.

In the second polymerization vessel, the propylene partial pressure was 13.
6 kg / cm ² , hydrogen was continuously fed to propylene in an amount of 0.029 mol / mol, and the polymerization temperature was 8
Polymerization of propylene was carried out at 0 ° C. (Step II) The polymerized polymer particles were discharged into a discharge tank and then transferred to a third polymerization vessel.

A propylene partial pressure of 2.0 was applied to the third polymerization vessel.
kg / cm ^2, 0 hydrogen and ethylene to propylene.
Polymerization of propylene and ethylene was carried out at a polymerization temperature of 70 ° C. by continuously feeding each at 032 mol / mol and 0.76 mol / mol. (Step III) The residence time in each polymerization vessel was 2 hours, and 20 kg of the polymer was extracted from the third polymerization vessel per hour. Table 1 shows the polymerization conditions
Shown in.

When a small amount of the polymer discharged from each polymerization reactor was extracted, the MFR of the polymer in the first polymerization reactor was 1.
8. The xylene-soluble component Xy was 1.4%, the MFR of the polymer in the second polymerization vessel was 5.3, and the ethylene content of the polymer in the third polymerization vessel was 8.8%. Since the polymerization rates of the respective polymerization vessels were 57%, 27% and 16%, the ethylene content in the components produced in the third polymerization vessel was 55% by weight.

This copolymer was added to Irganox-101.
0, Irgafos-168, and calcium stearate were each mixed at 1000 ppm and granulated with a 25 mm uniaxial extruder. The MFR was 19.2. The granulated copolymer was molded with a Toshiba IS-100E injection molding machine, and the physical properties were evaluated. The results are shown in Table 2.

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[Table 1]

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[Table 2]

Claims (2)

(57) [Claims] 1. A (A) catalyst component metallic magnesium and titanium compound as essential as a component, the Ia of the Periodic Table as the component (B), IIa, IIb, I
In the block copolymerization of propylene in the presence of a catalyst comprising at least one compound selected from the group IIb and IVb group organometallic compounds and an electron-donating compound as the component (C), in the step (I) A propylene polymer is produced, and in the step (II), a propylene homopolymer or a copolymer in which the reaction ratio of propylene and another α-olefin is 10/90 or less by weight, and the step (I) ) And the copolymerization ratio obtained in step (II) is 60% of the total polymer.
The polymer (H) obtained in the step (I) and the polymer (L) obtained in the step (II) have MFRs of Log (MFR (L) / MFR (H)). ) ≧ 1 and the copolymerization ratio in which the reaction ratio of the other α-olefin and propylene is 30/70 or more by weight in the step (III) is 5 to 40% by weight of the total polymer. A process for producing a block copolymer, which comprises carrying out continuous multi-stage polymerization by a gas phase method so that 2. The polymerization ratio of the polymer (H) obtained in step (I) and the polymer (L) obtained in step (II) is H /
The manufacturing method according to claim 1, wherein L ≧ 1.