JP2000063457A - Propylene-ethylene block copolymer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a propylene-ethylene block copolymer excellent in flexibility, transparency and heat resistance and reduced in the amount of a low mol.wt. matter which bleeds after fabrication. SOLUTION: A propylene-ethylene block copolymer is obtained by polymerization in the presence of a catalyst comprising [A] a titanium compound containing as essential components magnesium, titanium and a halogen, [B] an organoaluminum compound and [C] t-butyl(ethyl)dimethoxysilane, which comprises 1-40 wt.% of a polypropylene component comprising 100-95 mole % of a monomer unit based on propylene and 0-5 mole % of a monomer unit based on ethylene and 99-60 wt.% of a propylene-ethylene random copolymer component comprising 85-50 mole % of a monomer unit based on propylene and 15-50 mole % of a monomer unit based on ethylene.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a novel propylene-ethylene block copolymer. Specifically, it is a propylene-ethylene block copolymer characterized by being excellent in flexibility, heat resistance, and transparency, and further reduced in low molecular weight components bleeding on the surface of a molded article.

[0002]

2. Description of the Related Art Conventionally, olefinic thermoplastic elastomers have a good balance between economic efficiency and performance, and can be lightened and recycled, so that they can be used for various industrial parts and home appliances including automobile parts such as bumpers. Widely used in parts, films and sheets.

These olefinic thermoplastic elastomers include crystalline polyolefin components such as polypropylene and polyethylene, ethylene-propylene copolymer rubber (hereinafter abbreviated as EPR) and ethylene-propylene-.
A blending method in which a rubber component of a diene terpolymer rubber (hereinafter abbreviated as EPDM) is kneaded by an extruder,
A polymerization method is known in which both components are produced by a series of polymerizations using a highly active titanium catalyst.

Among these, EP is added to crystalline polyolefin.
The method of blending R and EPDM is excellent in flexibility and heat resistance, but is inferior in transparency, and thus its use is limited in film applications.

On the other hand, the above-mentioned polymerization method is disclosed in, for example, Japanese Patent Application Laid-Open No. 07-118354. In this method, in the presence of a stereoregular catalyst, by polymerizing a polypropylene component in the first step of polymerization and a propylene-ethylene random copolymer component in the second step of polymerization, flexibility, heat resistance, and transparency are obtained. Of the above-mentioned thermoplastic elastomers have been produced, the olefinic thermoplastic elastomers thus obtained have been desired to be further improved in terms of transparency and bleeding low molecular weight component.

Further, JP-A-6-240069 discloses a propylene-based resin composition having excellent mechanical properties in a wide elastic modulus range, excellent heat resistance, and free from surface tackiness of molded articles. . In this production method, an alkoxy group-containing aromatic compound and an organosilicon compound as an electron donor are used in the catalyst system, but the polypropylene component has a high polymerization ratio and the propylene-ethylene random copolymer component has a high polymerization ratio. Since it was small, it was not satisfactory in flexibility.

[0007]

SUMMARY OF THE INVENTION Therefore, the object of the present invention is to obtain a propylene having a good balance of flexibility, heat resistance and transparency, and a high polymerization activity in which low molecular weight components bleeding on the surface of a molded article are reduced. -To provide an ethylene block copolymer.

[0008]

Means for Solving the Problems As a result of repeated studies on the above problems, the present inventors have combined a catalyst system using a specific electron donor and polymerized the resulting propylene-ethylene having a specific composition. It was found that the block copolymer can solve all of these problems, and the present invention has been completed.

That is, the present invention is in the presence of a catalyst composed of [A] magnesium, titanium, and a titanium compound containing halogen as essential components, [B] organoaluminum compound, and [C] t-butyl (ethyl) dimethoxysilane. A propylene-ethylene block copolymer obtained by the method, wherein the composition has 100 units of propylene-based monomer units.
˜95 mol%, 1 to 40% by weight of polypropylene component having 0 to 5 mol% of ethylene-based monomer units, 85 to 50 mol% of propylene-based monomer units, and ethylene-based monomer units Is a propylene-ethylene random copolymer component having a content of 15 to 50 mol% in an amount of 99 to 60% by weight.

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION In the catalyst used in the present invention, the titanium compound [A] is not limited to any known titanium compound having high catalytic activity, which contains titanium, magnesium and halogen as essential components used in the polymerization of olefins. Used without. Such a titanium compound having a high catalytic activity is one in which various halogen compounds, particularly titanium tetrachloride, are supported on various magnesium compounds. As a method for producing this catalyst, a known method can be adopted without any limitation. Specifically, a method of co-milling titanium tetrachloride with a magnesium compound such as magnesium chloride, alcohol, ether,
Examples thereof include a method in which titanium halide and a magnesium compound are co-ground in the presence of an electron donor such as ester, ketone or aldehyde, or a method in which a titanium halide, a magnesium compound and an electron donor are contacted in a solvent. To be A method for producing such a titanium compound is described, for example, in JP-A-56-155206 and JP-A-56-1368.
06 publication, 57-34103 publication, 58-870 publication.
6, the same 58-83006, the same 58-138708, the same 5
8-183709, 59-206408, 59-2
19311, ibid. 60-81208, ibid. 60-8120
9, the same 60-186508, the same 60-192708, the same 61-211309, the same 61-271304, the same 62-.
15209, 62-11706, 62-7270.
2, the method shown in the same 62-104810 etc. is adopted.

Next, as the organoaluminum compound [B], a compound known to be used for polymerization of olefins is adopted without any limitation. For example, trialkyl aluminums such as trimethyl aluminum, triethyl aluminum, tri-n propyl aluminum, tri-n butyl aluminum, tri-i butyl aluminum, tri-n hexyl aluminum, tree n octyl aluminum, tree n decyl aluminum; diethyl aluminum Examples include diethylaluminum monohalides such as monochloride and diethylaluminum bromide; and alkylaluminum halides such as methylaluminum sesquichloride, ethylaluminum sesquichloride and ethylaluminum dichloride. In addition, alkoxy aluminums such as diethyl aluminum ethoxide, ethyl aluminum diethoxide, and ethyl aluminum sesquiethoxide can be used. You may use these organoaluminum compounds in combination of 2 or more types.

As the component [C] of the present invention, t-butyl (ethyl) dimethoxysilane is used.

[0013]

[Chemical 1]

In the above manufacturing method, t is used as the catalyst component.
By using -butyl (ethyl) dimethoxysilane, the obtained propylene-ethylene block copolymer is excellent in flexibility, heat resistance, and transparency as described above, and reduces low molecular weight components bleeding after the molding process. This is possible.

That is, with compounds other than t-butyl (ethyl) dimethoxysilane, the resulting propylene-ethylene block copolymer has an insufficient balance of flexibility and heat resistance and insufficient transparency, resulting in a poor molded article surface. It is not possible to reduce low molecular weight compounds that bleed.

In the production of the propylene-ethylene block copolymer of the present invention, it is obtained by stepwise polymerizing a polypropylene component and a propylene-ethylene random copolymer component which will be described later in the presence of the above catalyst component. However, in order to further reduce the low molecular weight product bleeding on the surface of the molded article, and to improve the fluidity of the polymer particles obtained by the polymerization, prior to the main polymerization performed in the presence of the catalyst component, It is effective to prepolymerize the titanium compound [A] with propylene or other α-olefin. The conditions of the prepolymerization are not particularly limited, but the following conditions are preferable. That is, [A] titanium compound [B] organic aluminum compound [D] general formula [I] R1nSi (OR2) 4-n [I] (wherein R1 and R2 are the same or different carbon atoms having 1 to 20 carbon atoms). Hydrogen, n is 0 ≦ n ≦ 4, and optionally [E] general formula [II] R3I [II] (wherein R3 is an iodine atom? Or a propylene or other α-olefin in the presence of an iodine compound represented by a hydrocarbon group having 1 to 20 carbon atoms.
A method of preliminarily polymerizing 0.1 to 50 g per 1 g of the titanium compound [A] is preferable.

As the [B] organoaluminum compound used in the prepolymerization, the above-mentioned compounds can be directly used.

The amount of the [B] organoaluminum compound used in the prepolymerization is not particularly limited, but in general, the Al / Ti (molar ratio) is 1 to 100 with respect to the Ti atom in the titanium compound. Preferably 3 to 3
It is preferably 10.

Further, as the [D] organosilicon compound, the compound represented by the general formula [I] can be used without any limitation.
1 to 2 carbon atoms represented by R1 and R2 in the general formula
As the hydrocarbon group of 0, methyl group, ethyl group, propyl group, isopropyl group, butyl group, isobutyl group, se
c-butyl group, pentyl group, isopentyl group, neopentyl group, hexyl group, heptyl group, octyl group, nonyl group, decyl group, and cyclopentyl group, alkyl group-substituted cyclopentyl group, cyclohexyl group, alkyl group-substituted cyclohexyl group as described below. Group, t-butyl group, t
-Amino group, phenyl group, alkyl group-substituted phenyl group and the like.

Examples of the organosilicon compound preferably used in the prepolymerization of the present invention are as follows. For example, t-butyl (ethyl) dimethoxysilane, trimethylmethoxysilane, trimethylethoxysilane, di-t-
Butyldimethoxysilane, di-t-amyldimethoxysilane, dicyclohexyldimethoxysilane, di (2-methylcyclopentyl) dimethoxysilane, di (3-methylcyclopentyl) dimethoxysilane, di (2-ethylcyclopentyl) dimethoxysilane, di (2,3) -Dimethylcyclopentyl) dimethoxysilane, di (2,4-dimethylcyclopentyl) dimethoxysilane, di (2,5
-Dimethylcyclopentyl) dimethoxysilane, di (2,3-diethylcyclopentyl) dimethoxysilane, di (2,3,4-trimethylcyclopentyl) dimethoxysilane, di (2,3,5-trimethylcyclopentyl) dimethoxysilane, di (2 , 3,4-Triethylcyclopentyl) dimethoxysilane, di (tetramethylcyclopentyl) dimethoxysilane, di (tetraethylcyclopentyl) dimethoxysilane, di (2-methylcyclohexyl) dimethoxysilane, di (3-methylcyclohexyl) dimethoxysilane, di ( 4-methylcyclohexyl) dimethoxysilane, di (2-ethylcyclohexyl) dimethoxysilane, di (2,3-dimethylcyclohexyl) dimethoxysilane, di (2,4-dimethylcyclohexyl) dimeth Shishiran, di (2,5-dimethylcyclohexyl) dimethoxysilane, di (2,6
Dimethylcyclohexyl) dimethoxysilane, di (2,2
3-diethylcyclohexyl) dimethoxysilane, di (2,3,4-trimethylcyclohexyl) dimethoxysilane, di (2,3,5-trimethylcyclohexyl)
Dimethoxysilane, di (2,3,6-trimethylcyclohexyl) dimethoxysilane, di (2,4,5-trimethylcyclohexyl) dimethoxysilane, di (2,4,4)
6-trimethylcyclohexyl) dimethoxysilane, di (2,3,4-triethylcyclohexyl) dimethoxysilane, di (2,3,4,5-tetramethylcyclohexyl) dimethoxysilane, di (2,3,4,6-tetra Methylcyclohexyl) dimethoxysilane, di (2,2
3,5,6-Tetramethylcyclohexyl) dimethoxysilane, di (2,3,4,5-tetraethylcyclohexyl) dimethoxysilane, di (pentamethylcyclohexyl) dimethoxysilane, di (pentaethylcyclohexyl) dimethoxysilane, t-amyl Methyldimethoxysilane, cyclopentylmethyldimethoxysilane, cyclopentylethyldimethoxysilane, cyclopentylisobutyldimethoxysilane, dicyclopentyldimethoxysilane, cyclohexylmethyldimethoxysilane, cyclohexylethyldimethoxysilane, cyclohexylisobutyldimethoxysilane, diphenyldimethoxysilane, phenylmethyldimethoxysilane, ethyltrimethoxysilane Methoxysilane, ethyltriethoxydimethoxysilane, methyltrimetho Shishiran, n- propyl triethoxysilane, decyltriethoxysilane, phenyltrimethoxysilane, methyltriethoxysilane, ethyltriethoxysilane, t- butyl triethoxysilane, n
-Butyltriethoxysilane, cyclopentyltrimethoxysilane, cyclohexyltrimethoxysilane, cyclopentyltrimethoxysilane, cyclohexyltriethoxysilane, phenyltriethoxysilane, ethyl silicate, butyl silicate and the like can be mentioned.

The amount of the organosilicon compound used in the above-mentioned prepolymerization is not particularly limited, but it is generally 0.1 to 100 in Si / Ti (molar ratio) with respect to Ti atoms in the titanium compound. Is preferable, and 0.5 to
It is preferably 10.

Propylene obtained in prepolymerization
It is preferable to use the [E] iodine compound in order to further reduce the amount of the low molecular weight component of the ethylene block copolymer.

As the iodine compound [E], the compound represented by the general formula [II] can be used without any limitation. The general formula [I
R3 in [I] is an iodine atom or has 1 to 1 carbon atoms.
20 hydrocarbon groups, and in the case of a hydrocarbon group, a hydrocarbon group such as an alkyl group, an alkenyl group, an alkynyl group, or an aryl group. Specific examples of the iodine compound preferably used in the present invention include iodine, ethyl iodide, methyl iodide, propyl iodide, butyl iodide, benzene iodide, p-toluene iodide and the like. . Of these, iodine, methyl iodide and ethyl iodide are preferable.

The amount of the iodine compound used in the prepolymerization is not particularly limited, but Ti in the titanium compound is generally used.
The I / Ti (molar ratio) is preferably 0.1 to 100, more preferably 0.5 to 50, with respect to the atoms.

The above-mentioned components used in the prepolymerization may be added one after another, or may be mixed together. The order of addition in the case of sequential addition is not particularly limited.

The amount of propylene or α-olefin polymerized in the prepolymerization is in the range of 0.1 to 50 g, preferably 1 to 20 g per 1 g of titanium. Examples of α-olefins other than propylene used in the prepolymerization include linear methyl α-olefins such as ethylene, butene-1, pentene-1, and hexene-1, and 3-methylbutene-1,4-methylpentene- 1, branched α- such as vinylcycloalkane
Examples include olefins. It is also possible to use two or more of the above-mentioned propylene or α-olefin at the same time. It is also possible to make hydrogen coexist by prepolymerization.

For the prepolymerization, it is usually preferable to apply slurry polymerization, and a saturated aliphatic hydrocarbon or aromatic hydrocarbon such as hexane, heptane, cyclohexane, benzene and toluene is used alone or a mixed solution thereof is used as a solvent. be able to. The prepolymerization temperature is generally -2.
0 to 100 ° C., particularly 0 to 60 ° C. is preferable, and when the prepolymerization is carried out in multiple stages, the temperature conditions of the polymerization may be different in each stage. The pre-polymerization time may be appropriately determined according to the pre-polymerization temperature and the polymerization amount in the pre-polymerization, and the pressure in the pre-polymerization is not particularly limited, but in the case of slurry polymerization, it is generally from atmospheric pressure to 0. It is about 5 MPa. The prepolymerization may be carried out batchwise, semi-batchly or continuously. At the end of the prepolymerization, it is preferable to wash with saturated aliphatic hydrocarbons or aromatic hydrocarbons such as hexane, heptane, cyclohexane, benzene and toluene, and the number of washings is usually preferably 4 to 6 times.

In the present invention, the main polymerization is carried out next to the preliminary polymerization which is carried out if necessary.

In the present invention, in the main polymerization, the polypropylene component is first polymerized in the presence of the above catalyst, and then the propylene-ethylene random copolymer component is polymerized.

The above-mentioned main polymerization conditions in the present invention are not particularly limited as long as the effects of the present invention can be observed, and known methods can be adopted, but the following conditions are generally preferred.

The amount of the above-mentioned [B] organoaluminum compound used in the main polymerization is not particularly limited, but in general, Al / Ti based on the Ti atom in the titanium compound obtained by the prepolymerization.
The (molar ratio) is preferably 10 to 1000, and more preferably 20 to 700.

Further, the amount of [C] t-butyl (ethyl) dimethoxysilane used is not particularly limited, but in general, Si / Ti (molar ratio) is 0.1 to Ti atom of the titanium compound.
It is preferably 1 to 1000, and further 1 to 500
Is preferred. The order of adding the components used in the main polymerization is not particularly limited, and organoaluminum and organosilicon compounds may be mixed. Polymerization of the polypropylene component may be carried out by supplying propylene alone or by supplying ethylene so that the ratio of ethylene-based monomer units falls within the range described below. To exemplify a typical condition of the method for polymerizing the polypropylene component, it is preferable that the polymerization temperature is 80 ° C. or lower, and more preferably 20 to 70 ° C. If necessary, hydrogen may be allowed to coexist as a molecular weight modifier. Further, the polymerization may be any method such as slurry polymerization using propylene itself as a solvent, gas phase polymerization, solution polymerization and the like. Slurry polymerization using propylene itself as a solvent is a preferred embodiment in view of the simplicity of the process, the reaction rate, and the particle properties of the resulting copolymer.
The polymerization system may be a batch system, a semi-batch system, or a continuous system. Further, the polymerization can be carried out in two or more stages with different conditions such as hydrogen concentration and polymerization temperature.

Next, random copolymerization of propylene and ethylene is carried out. Random copolymerization of propylene and ethylene, in the case of slurry polymerization using propylene itself as a solvent, by supplying ethylene gas subsequent to the propylene polymerization, and in the case of gas phase polymerization, supplying a mixed gas of propylene and ethylene. It is carried out by doing.

The polymerization temperature for the random copolymerization of propylene and ethylene is 80 ° C. or lower, preferably 20 to 70 ° C. If necessary, hydrogen can be used as a molecular weight regulator, and the hydrogen concentration at that time can be changed in multiple stages to carry out the polymerization.

By selecting a specific catalyst in the random copolymerization of ethylene and propylene subsequent to the polymerization of the polypropylene component, a propylene block copolymer having the desired molecular weight distribution, crystallinity distribution, etc. can be produced in one step. However, in order to obtain the propylene-ethylene block copolymer of the present invention, random copolymerization is carried out in multiple stages, and it can be produced by a method in which the polymerization conditions such as hydrogen concentration and ethylene concentration are changed at each stage. preferable. In such multistage copolymerization, the copolymerization is carried out by appropriately adjusting the ratio of the polypropylene component and the propylene-ethylene random copolymer component described above according to the polymerization conditions.

The random copolymerization of propylene and ethylene may be carried out batchwise, semi-batchly or continuously, and the polymerization may be carried out in multiple stages. Further, the polymerization in this step may employ any of slurry polymerization, gas phase polymerization, and solution polymerization.

After completion of the main polymerization, the propylene-ethylene block copolymer of the present invention can be obtained by evaporating the monomer from the polymerization system. This propylene-ethylene block copolymer can be subjected to known washing or countercurrent washing with a hydrocarbon having a carbon number of 7 or less.

The propylene-ethylene block copolymer of the present invention is obtained by stepwise polymerizing a polypropylene component and then a propylene-ethylene random copolymer using the above catalyst. .

In the present invention, the propylene-ethylene block copolymer obtained by using the above-mentioned polymerization catalyst has 100 to 95 mol% of propylene-based monomer units and 0 to 5 of ethylene-based monomer units. 1 to 40% by weight of polypropylene component and 8% of propylene monomer, which are mol%
5 to 50 mol%, ethylene monomer 15 to 50 mol% propylene-ethylene random copolymer component 99
It is important to consist of ˜60% by weight.

The polypropylene component and the propylene-ethylene random copolymer component can be separated and analyzed by the temperature rising elution fractionation method. Here, the temperature rising elution fractionation method refers to, for example, Journal of App.
lied PolymerScience; Appli
ed Polymer Symposium 45,1
-24 (1990). First, a high-temperature polymer solution is introduced into a column packed with a diatomaceous earth filler, and the column temperature is gradually lowered to crystallize the filler surface in order from the component with the highest melting point, then the column temperature. Is a method in which components having a lower melting point are sequentially eluted to increase the elution.

In the present invention, as shown in the examples, SSC-7300 type manufactured by Senshu Scientific Co., Ltd. is used as a measuring device, solvent: o-dichlorobenzene, flow rate: 2.5 m.
1 / min, temperature rising rate; 4 ° C./Hr, column: φ30 m
By measuring the eluted component of the propylene-ethylene block copolymer under the condition of m × 300 mm, 100 ° C.
The above-mentioned elution component is separated as a polypropylene component, and the elution component below 100 ° C. is separated as a propylene-ethylene random copolymer component.

The polypropylene component of the present invention is a propylene homopolymer or a propylene-ethylene random copolymer having an ethylene content of 5 mol% or less. When the ethylene content exceeds 5 mol%, the melting point (Tm) is lowered and the heat resistance is impaired, which is not preferable. In order to obtain a good balance of physical properties, the ethylene content is preferably 4 mol% or less, more preferably 3 mol% or less.

The melting point (Tm) of the propylene-ethylene block copolymer of the present invention is preferably 150 ° C. ≦ Tm ≦ 165 ° C. because it has heat resistance. When the ethylene content in the polypropylene component exceeds 5 mol% and the melting point is 150 ° C. or lower, the heat resistance of the resin is inferior, which is not preferable. Moreover, it is generally difficult and not industrial to obtain a propylene-ethylene block copolymer having a melting point of higher than 165 ° C.

The propylene-ethylene random copolymer component of the present invention has a propylene-based monomer unit of 85-85.
50 mol%, 15 to 50 monomer units based on ethylene
Molar% is necessary for achieving the object of the present invention. That is, the monomer unit based on ethylene is 15
If it is less than mol%, the flexibility of the molded product becomes insufficient, which is not preferable. On the other hand, when the monomer unit based on ethylene exceeds 50 mol%, the surface bleeding material increases in the case of a molded product, which causes a decrease in transparency, which is not preferable. In order to obtain a good physical property balance, the ethylene-based monomer unit of the propylene-ethylene random copolymer component is preferably 17 to 48 mol%,
More preferably, it is 20 to 45 mol%.

In the propylene-ethylene block copolymer of the present invention, the proportion of the polypropylene component and the propylene-ethylene random copolymer component is from 1 to 40% by weight of the polypropylene component and from 99 to 99 of the propylene-ethylene random copolymer component. It is 60% by weight.

When the polypropylene component is less than 1% by weight, the block copolymer particles are apt to stick to each other and the production becomes difficult, and further the heat resistance becomes insufficient, which is not preferable. On the other hand, when the proportion of the polypropylene component exceeds 40% by weight, flexibility and transparency are deteriorated, and a propylene-ethylene block copolymer having desired physical properties cannot be obtained. Considering the balance of flexibility, transparency, heat resistance, mechanical properties, etc., the preferred range of the polypropylene component is 1 to 30% by weight, more preferably 1 to 20% by weight.

In the present invention, the ratio of the polypropylene component to the propylene-ethylene random copolymer component and the ratio of the ethylene-based monomer in each component are
It can be adjusted by the polymerization conditions such as polymerization time, polymerization temperature, and ethylene concentration.

The propylene-ethylene block copolymer of the present invention comprises a polypropylene component having the above-mentioned specific composition,
Since it is composed of a propylene-ethylene random copolymer component, the flexural modulus showing flexibility is 300 MPa or less. In order to have more flexibility, the flexural modulus is 250
It is preferably not more than MPa, more preferably not more than 200 MPa.

The propylene-ethylene block copolymer of the present invention is a so-called block copolymer having a polypropylene component and a propylene-ethylene random copolymer component arranged in one molecular chain and / or a polypropylene component and a propylene- The ethylene random copolymer component and the molecular chains of the individual components are finely mixed by polymerization, and good transparency can be exhibited.

The melt flow rate of the propylene-ethylene block copolymer in the present invention is generally 0.1.
-50g / 10min, preferably 0.1-30g / 1
0 min, more preferably 0.1 to 20 g / 10 min
Is. When the melt flow rate is less than 0.1 g / 10 min, molding becomes difficult, and when it exceeds 50 g / 10 min, bleeding of low molecular weight substances increases, which is not preferable.

In the present invention, as a method for adjusting the melt flow rate of the propylene-ethylene block copolymer, a method of adjusting the molecular weight by allowing hydrogen to coexist during the polymerization and a propylene-ethylene obtained by allowing a small amount of hydrogen to coexist. There is a method of adjusting the molecular weight by adding an organic peroxide to the block copolymer particles and melt-kneading.

In the present invention, when hydrogen is allowed to coexist during the polymerization so that the propylene-ethylene block copolymer has a melt flow rate of 0.1 to 50 g / 10 min,
If the molecular weight is adjusted by hydrogen to increase the melt flow rate, the obtained propylene-ethylene block copolymer particles will be in a lumpy state, which is difficult to manufacture in a plant, which is not preferable. Therefore, the melt flow rate of the propylene-ethylene block copolymer particles obtained by allowing a small amount of hydrogen to coexist during the polymerization is 0.01 to 10 g / 10.
min, preferably 0.01 to 5 g / 10 min, more preferably 0.01 to 3 g / 10 min, and melt kneading with an organic peroxide to achieve a target melt flow rate. The propylene-ethylene block copolymer particles have a melt flow rate of 0.01 g / 10.
If it is less than min, the degree of decomposition by the organic peroxide must be increased, and the moldability is lowered, which is not preferable. On the other hand, if the melt flow rate of the propylene-ethylene block copolymer particles exceeds 10 g / 10 min, the polymer particles will be in a lumpy state and the production in the plant will be difficult, which is not preferable.

Further, the bulk density of the obtained propylene-ethylene block copolymer particles is such that the bulk density of the obtained polymer particles is 0.25 g / cc in order not to reduce the fluidity of the polymer particles in the plant. Or more, preferably 0.28 g / cc, more preferably 0.30 g / cc
That is all.

As the organic peroxide used for decomposing the propylene-ethylene block copolymer particles used in the present invention and adjusting the molecular weight, known compounds can be used without any limitation. To illustrate, for example, ketone peroxides such as methyl ethyl ketone peroxide, methyl isobutyl ketone peroxide, and cyclohexanone peroxide; diacyl peroxides such as isobutyryl peroxide, lauroyl peroxide, and benzoyl peroxide; and hydrol such as diisopropylbenzene hydroperoxide. Peroxide; dicumyl peroxide, 2,5-dimethyl-2,5-di- (t-butylperoxy) hexane,
1,3-bis- (t-butylperoxy-isopropyl) -benzene, di-t-butylperoxide, 2,
5-dimethyl-2,5-di- (t-butylperoxy)
-Dialkyl peroxide such as hexane-3; 1,1
Peroxyketals such as -di-t-butylperoxy-3,3,5-trimethylcyclohexane and 2,2-di- (t-butylperoxy) -butane; t-butylperoxy-pivalate, t-butyl Examples thereof include alkyl peresters such as peroxybenzoate; percarbonates such as t-butyl peroxyisopropyl carbonate.

The above-mentioned kneading of the propylene-ethylene block copolymer particles and the organic peroxide is generally carried out at a temperature above the melting point of the propylene-ethylene block copolymer and the decomposition temperature of the organic peroxide. It is carried out using a known kneading device. For example, using a screw extruder, Banbury mixer, mixing roll, etc.,
A method of kneading at 0 ° C, preferably 170 to 300 ° C can be adopted. Further, the melt-kneading can be performed in a stream of an inert gas such as nitrogen gas. It is also possible to carry out preliminary kneading using a known mixing device such as a tumbler or a Henschel mixer before the melt kneading.

The propylene-ethylene block copolymer of the present invention has a small amount of catalyst residue remaining in the polymer, and is an additive produced by yellowing after molding or by liberation of fatty acids when metal soap is used as a chlorine scavenger. Less bleeding,
Another feature is its excellent appearance.

That is, in the propylene-ethylene block copolymer of the present invention, the residual titanium atom is 5 pp.
m or less, more preferably 3 ppm or less, further preferably 2 ppm or less. On the other hand, the chlorine atom content is 30 ppm or less, preferably 20 ppm or less. 5 titanium atoms
When the amount of chlorine atoms exceeds 30 ppm and the amount of chlorine atoms exceeds 30 ppm,
It is not preferable because yellowing occurs during molding and fatty acids are liberated from the added metal soap to increase the bleeding component, resulting in poor appearance.

These atomic concentrations are values measured by the fluorescent X-ray method. These values for the propylene-ethylene block copolymer of the present invention are those for the block copolymer itself obtained by polymerization.

The propylene-ethylene block copolymer of the present invention may be mixed with commercially available additives such as an antioxidant, a heat stabilizer and a chlorine scavenger, and then pelletized by an extruder.

[0060]

The propylene-ethylene copolymer obtained by the method for producing a propylene-ethylene block copolymer of the present invention is excellent in flexibility, heat resistance and transparency and has a low molecular weight component that bleeds on the surface of a molded article. It has been reduced.

Therefore, it can be suitably used in various fields in which conventional soft PVC and thermoplastic elastomer are used. For example, in the extrusion and film fields, stretch films for packaging, wrap films, shrink films, films for sealants, adhesive tapes, marking films, dicing films, surface protective films, steel sheet / plywood protective films, automobile protective films, agricultural films. , Medical films, building materials-related films, stationery sheets, waterproof sheets, automotive interior skin materials, insulating sheets, wire coating materials, etc. in the injection field, in automobile parts, mudguards, bumpers, lamp packings, and in the home appliances field, Suitable for various packings, ski shoes, grips and roller skates.

[0062]

EXAMPLES The present invention will be described below with reference to examples and comparative examples, but the present invention is not limited to these examples. The measuring method used in the following examples will be described.

1) Amount of polypropylene component, propylene-
Measurement of amount of ethylene random copolymer component (temperature rising elution fractionation method) SSC-7300 manufactured by Senshu Scientific Co., Ltd. was used, and the measurement was performed under the following measurement conditions.

Solvent: o-dichlorobenzene Flow rate: 2.5 ml / min Temperature rising rate: 4 ° C./Hr Sample concentration: 0.7 wt% Sample injection amount: 100 ml Detector: Infrared detector, wavelength 3.41 m column : Φ30 mm × 300 mm Filler: Chromosorb P 30-60 mes
h Column cooling rate: 2.0 ° C./Hr 2) Measurement of ethylene and propylene contents in propylene-ethylene random copolymer It was measured using a 13C-NMR spectrometer using JEOL GSX-270.

3) Melt flow rate According to ASTM D-1238.

4) Bulk density It was based on JIS K6721.

5) Measurement of residual titanium concentration and chlorine concentration in the polymer Approximately 5 g of the polymer was press-molded at 230 ° C. to prepare a disc-shaped sheet, and then a fully automatic fluorescent X-ray analyzer system manufactured by Rigaku Denki Co., Ltd. The measurement was performed using 3080.

7) Measurement of melting point (Tm) Using DCS200 manufactured by Seiko Denshi Kogyo Co., Ltd., by melting at 230 ° C. for 5 minutes by a thermal flow rate differential scanning calorimetry method, cooling at a temperature lowering rate of 10 ° C./minute, and then increasing. The position of the peak of the maximum endothermic peak temperature indicating melting, which was measured at a temperature rate of 10 ° C./min, was determined.

8) Flexural modulus It conformed to JIS K7203.

9) Transparency (haze value) A 1 mmt test piece was prepared by injection molding, and JIS K
7105.

10) Evaluation of Bleed Component Amount (Soluble Content at Room Temperature Heptane) The above 1 mmt (about 2 g) test piece was aged at 40 ° C. for 3 days, and then stirred at room temperature for 1 hour with 100 ml of heptane. And washed. The obtained heptane was concentrated and the amount of the bleed component was evaluated.

11) Vigat softening temperature It was measured according to JIS k7206 under a load of 250 g.

Example 1 [Preparation of Titanium Compound] The method for preparing the titanium component is described in JP-A-5-56.
The method was carried out according to the method of Example 1 of JP-A-8-83006. That is, 0.95 g of anhydrous magnesium chloride (10 mm
ol), 10 ml of decane, and 4.7 ml (30 mmol) of 2-ethylhexyl alcohol were heated and stirred at 125 ° C. for 2 hours. 0.55 g of phthalic anhydride in this solution
(6.75 mmol) was added, and the mixture was further stirred and mixed at 125 ° C. for 1 hour to obtain a uniform solution. After cooling to room temperature, 40 ml of titanium tetrachloride (0.
(36 mol) was added dropwise over 1 hour.
Then, the temperature of this mixed solution was raised to 110 ° C. over 2 hours, and when it reached 110 ° C., 0.54 ml of diisobutyl phthalate was added, whereby 2 hours 11
It was kept under stirring at 0 ° C. After the reaction for 2 hours, the solid portion was collected by filtration, resuspended with 200 ml of TiCl4, and then heated again at 110 ° C. for 2 hours. After the reaction was completed, the solid portion was collected again by hot filtration, and thoroughly washed with decane and hexane until no free titanium compound was detected in the washing liquid. The composition of the solid Ti catalyst was 2.1% by weight titanium, 57% by weight chlorine, 18.0% by weight magnesium, and 21.9% by weight diisobutyl starrate.

(Preliminary Polymerization) A glass autoclave reactor having an internal volume of 1 liter equipped with a stirrer was sufficiently replaced with nitrogen gas, and then the temperature inside the reactor was kept at 10 ° C., 400 ml of n-hexane, and 13% of triethylaluminum. 0.8 mm
ol, t-butyl (ethyl) dimethoxysilane 1.38
mmol, ethyl iodide 6.9 mmol and 1.38 mmol of solid Ti catalyst in terms of Ti atom were charged, and then propylene was adjusted to 3 g per 1 g of the solid catalyst component.
It was continuously introduced into the reactor for 0 minutes. The temperature during this period was kept at 15 ° C. After the supply of propylene was stopped and the inside of the reactor was sufficiently replaced with nitrogen gas, 1-butene was continuously introduced into the reactor for 1 hour so that 1 g of the solid catalyst component was 15 g. After the supply of 1-butene was stopped, the inside of the reactor was sufficiently replaced with nitrogen gas, and the obtained titanium-containing polypropylene was washed 4 times with purified n-hexane. As a result of analysis, 2.1 g per 1 g of solid catalyst
Of propylene and 9.2 g of 1-butene had been polymerized.

(Main Polymerization) 1 liter of liquid propylene, 0.70 mmol of triethylerminium, 0.35 mmol of t-butyl (ethyl) dimethoxysilene, and hydrogen in the gas phase were placed in a 2 liter autoclave which had been subjected to N2 substitution. Of 0.8 mol% was added, and the internal temperature of the autoclave was raised to 55 ° C. Ethylene was supplied so as to be 0.8 mol% while confirming the ethylene gas concentration in the gas phase by a gas chromatograph. Next, 0.0014 mmol of a titanium-containing propylene-1-butene copolymer obtained by preliminary polymerization was added as a Ti atom, and propylene was polymerized at 55 ° C. for 20 minutes (first step). Next, ethylene was supplied so as to be 8 mol% while confirming the ethylene gas concentration in the gas phase with a gas chromatograph, and polymerization was carried out for 120 minutes (second step). The yield of the obtained polymer was 154 g, the polymerization activity at this time was 51000 g / g-cat, the bulk density of the polymer particles was 0.33 g / cc, and the melt flow rate was 0.1 g / 1.
It was 0 min. The results are shown in Table 1.

[Granulation] Unreacted monomer was purged to obtain a polymer. The obtained polymer was dried at 70 ° C. for 1 hour. Next, 2,6-di-t-butyl-p was used as an antioxidant.
-0.1 part by weight of cresol, 0.1 part by weight of calcium stearate as a chlorine scavenger, 1 as an organic peroxide
After 0.03 parts by weight of 3-bis- (t-butylperoxyisopropyl) benzene was added and mixed, the mixture was extruded at a cylinder temperature of 250 ° C. to obtain pellets.

[Injection molding] Bending and Bigatt softening point test pieces and a 1 mmt haze measuring plate were prepared from the obtained pellets at 230 ° C and a mold temperature of 40 ° C using a 15t injection molding machine. The bending and Bigatt softening point test pieces were measured after being left at room temperature for 48 hours. The haze was measured immediately after molding and after aging at 40 ° C. for 3 days.
As for the heptane-soluble component at room temperature, 2 g of an aged test piece for measuring haze was washed with 100 ml of heptane for 1 hour. The results are shown in Table 2.

Example 2 An antioxidant and a chlorine scavenger were added to the polymer obtained in Example 1 in the same manner as in Example 1 to prepare 1,3-bis- (t-butyl) as an organic peroxide. Peroxyisopropyl)
0.05 parts by weight of benzene was added and mixed, and then extruded at a cylinder temperature of 250 ° C. to obtain pellets. Otherwise, the same operation as in Example 1 was performed. The injection molding was performed in the same manner as in Example 1. The results are shown in Tables 1 and 2.

Example 3 In the step 2 of the main polymerization of Example 1, ethylene was fed so that the ethylene gas concentration in the gas phase was maintained at 12 mol% while confirming by gas chromatography, and the polymerization was carried out for 120 minutes. The same operation as in Example 1 was performed except that the steps were performed.
The yield of the obtained polymer was 163 g, the polymerization activity at this time was 54000 g / g-cat, the bulk density of the polymer particles was 0.30 g / cc, and the melt flow rate was 0.0.
It was 5 g / 10 min. The results are shown in Table 1.

[Granulation] An antioxidant and a chlorine scavenger were added to the obtained polymer in the same manner as in Example 1 to prepare 1,3-bis- (t-butylperoxyisopropyl) as an organic peroxide. 0.05 parts by weight of benzene was added and mixed, and then extruded at a cylinder temperature of 250 ° C. to obtain pellets.

[Injection molding] The same operation as in Example 1 was performed. The results are shown in Table 2.

Example 4 In the first step of the main polymerization of Example 1, the same operation was performed except that ethylene was not supplied. The yield of the obtained polymer was 140 g, and the polymerization activity at this time was 470.
00g / g-cat, the bulk density of the polymer particles is 0.34
g / cc, melt flow rate is 0.11 g / 10 mi
It was n.

For [granulation] and [injection molding], the same operations as in Example 1 were performed. The results are shown in Tables 1 and 2.

Example 5 In the first step of the main polymerization of Example 1, the polymerization time was set to 50.
In the second step, the ethylene gas concentration in the gas phase was 13 m while checking the ethylene gas concentration in the gas phase with a gas chromatograph.
The same operation as in Example 1 was performed in which the polymerization was performed for 90 minutes by supplying so that the amount became ol%. The yield of the obtained polymer was 150 g, and the polymerization activity at this time was 50,000 g /
g-cat, bulk density of polymer particles is 0.31 g / c
c, the melt flow rate was 0.07 g / 10 min.

For [granulation] and [injection molding], the same operations as in Example 2 were performed. The results are shown in Tables 1 and 2.

Example 6 Example 1 was repeated except that in the first step of the main polymerization of Example 1, ethylene was fed so that the ethylene gas concentration in the gas phase was 1.5 mol% while confirming by gas chromatography. The same operation was performed. The yield of the obtained polymer was 141 g, and the polymerization activity at this time was 47,000 g / g.
-Cat, the bulk density of the polymer particles is 0.29 g / cc,
The melt flow rate was 0.04 g / 10 min.

For [granulation] and [injection molding], the same operations as in Example 1 were performed. The results are shown in Tables 1 and 2.

Example 7 In the first step of the main polymerization of Example 1, the polymerization time was adjusted to 10
The same operation as in Example 1 was performed except that the time was changed. The yield of the obtained polymer was 162 g, the polymerization activity at this time was 54000 g / g-cat, the bulk density of the polymer particles was 0.29 g / cc, and the melt flow rate was 0.05 g.
It was / 10 min.

For [granulation] and [injection molding], the same operations as in Example 1 were performed. The results are shown in Tables 1 and 2.

Example 8 The same operation as in Example 1 was carried out except that hydrogen was added so that the concentration in the gas phase was 0.5 mol% in the first step of the main polymerization of Example 1. The yield of the obtained polymer is 1
61 g, and the polymerization activity at this time was 54000 g / g-
Cat, the bulk density of the polymer particles was 0.38 g / cc, and the melt flow rate was 0.05 g / 10 min.

For [granulation] and [injection molding], the same operations as in Example 1 were performed. The results are shown in Tables 1 and 2.

Example 9 In the first step of the main polymerization of Example 1, the same operation as in Example 1 was performed except that hydrogen was added so that the concentration in the gas phase was 1.4 mol%. The yield of the obtained polymer is 1
29 g, and the polymerization activity at this time was 43000 g / g-c.
At, the bulk density of the polymer particles was 0.29 g / cc, and the melt flow rate was 0.21 g / 10 min.

For [granulation] and [injection molding], the same operations as in Example 1 were performed. The results are shown in Tables 1 and 2.

Example 10 The same operation as in Example 1 was carried out except that 0.70 mmol of ethylaluminum sesquiethoxide was added in the second step of Example 1. The yield of the obtained polymer is 1
21 g, and the polymerization activity at this time was 40,000 g / g-
Cat, the bulk density of the polymer particles was 0.28 g / cc, and the melt flow rate was 0.10 g / 10 min.

For [granulation] and [injection molding], the same operations as in Example 1 were performed. The results are shown in Tables 1 and 2.

Comparative Example 1 The polymerization time was 110 in the first step of the main polymerization of Example 1.
The same operation as in Example 1 was performed, except that the polymerization time was 30 minutes in the second step. The yield of the obtained polymer was 120 g, and the polymerization activity at this time was 400
00g / g-cat, the bulk density of the polymer particles is 0.36
g / cc, melt flow rate is 0.25g / 10mi
It was n.

For [granulation] and [injection molding], the same operations as in Example 1 were performed. The results are shown in Tables 1 and 2.

Comparative Example 2 With Example 1 except that ethylene was fed in the first step of the main polymerization of Example 1 so that the ethylene gas concentration in the gas phase was 2.5 mol% as confirmed by gas chromatography. The same operation was performed. The yield of the obtained polymer is 1
52 g, and the polymerization activity at this time was 52000 g / g-
Cat, the bulk density of the polymer particles was 0.24 g / cc, and the melt flow rate was 0.07 g / 10 min.

For [granulation] and [injection molding], the same operations as in Example 1 were performed. The results are shown in Tables 1 and 2.

Comparative Example 3 As in Example 1 except that ethylene was fed in the second step of the main polymerization of Example 1 so that the ethylene gas concentration in the gas phase was 20.0 mol% as confirmed by gas chromatography. The same operation was performed. The yield of the obtained polymer was 171 g, and the polymerization activity at this time was 57,000 g / g.
-Cat, the bulk density of the polymer particles was lumpy and could not be measured. Melt flow rate is 0.06g / 10m
It was in.

For [granulation] and [injection molding], the same operations as in Example 1 were performed. The results are shown in Tables 1 and 2.

Comparative Example 4 The same as Example 1 except that ethylene was fed in the second step of the main polymerization of Example 1 so that the ethylene gas concentration in the gas phase was 3 mol% as confirmed by gas chromatography. The operation was performed. The yield of the obtained polymer is 116.
g, and the polymerization activity at this time is 39000 g / g-ca.
t, the bulk density of the polymer particles was 0.41 g / cc, and the melt flow rate was 0.28 g / 10 min.

For [granulation] and [injection molding], the same operations as in Example 2 were performed. The results are shown in Tables 1 and 2.

Comparative Example 5 The same operation as in Example 1 was carried out except that diphenyldiethoxysilane was used in place of t-butyl (ethyl) dimethoxysilane in the main polymerization of Example 1. The yield of the obtained polymer was 105 g, the polymerization activity at this time was 35,000 g / g-cat, and the bulk density of the polymer particles was partly lumpy and could not be measured. The melt flow rate was 0.13 g / 10 min.

For [granulation] and [injection molding], the same operations as in Example 1 were performed. The results are shown in Tables 1 and 2.

Comparative Example 6 The same operation as in Example 1 was carried out except that dicyclopeentyldimethoxysilane was used in place of t-butyl (ethyl) dimethoxysilane in the main polymerization of Example 1. The yield of the obtained polymer was 155 g, the polymerization activity at this time was 52000 g / g-cat, the bulk density of the polymer particles was 0.31 g / cc, and the melt flow rate was 0.1 g / 10 min.

The operations of "granulation" and "injection molding" were the same as in Example 1. The results are shown in Tables 1 and 2.

Comparative Example 7 The same operation as in Example 1 was carried out except that dicyclopetyltyldimethoxysilane was used in place of t-butyl (ethyl) dimethoxysilane in the main polymerization of Example 1. The yield of the obtained polymer was 100 g, the polymerization activity at this time was 33000 g / g-cat, and the bulk density of the polymer particles was partly lumpy and could not be measured. The melt flow rate was 0.14 g / 10 min.

For [granulation] and [injection molding], the same operations as in Example 1 were performed. The results are shown in Tables 1 and 2.

Comparative Example 8 (Preliminary Polymerization) A glass autoclave reactor having an internal volume of 1 liter equipped with a stirrer was sufficiently replaced with nitrogen gas, and then the temperature inside the reactor was kept at 10 ° C. to prepare n-hexane 400.
ml, butyl acetate 0.18 mmol, ethyl iodide 2
2.7 mmol, diethyl aluminum chloride 1
After adding 8.5 mmol and titanium trichloride (made by Marubeni Solvay Chemical Co., Inc.) 22.7 mmol, propylene was continuously introduced into the reactor for 30 minutes so that the amount of propylene was 3 g per 1 g of titanium trichloride. After the supply of propylene was stopped and the inside of the reactor was sufficiently replaced with nitrogen gas, the obtained titanium-containing polypropylene was washed 4 times with purified hexane. As a result of the analysis, 2.9 g of propylene was polymerized per 1 g of titanium trichloride.

(Main Polymerization) 1 liter of liquid propylene and 0.70 mmol of diethylaluminum chloride were added to a 2 liter autoclave substituted with N2.
The internal temperature of the autoclave was raised to 55 ° C. Ethylene was supplied at 0.5 mol% while confirming the ethylene gas concentration in the gas phase by a gas chromatograph. Titanium-containing polypropylene as titanium trichloride 0.087mmo
1, and propylene was polymerized at 55 ° C. for 30 minutes (first step). Next, 0.50 mmol of ethylaluminum sesquiethoxide (Et3Al2 (OEt) 3),
And 0.014 mmol of methyl methacrylate were added, ethylene was supplied, and while confirming the ethylene gas concentration in the gas phase with a gas chromatograph so as to be 12 mol%, polymerization was performed for 110 minutes (No. Two steps). The yield of the obtained polymer was 126 g, the polymerization activity at this time was 9000 g / g-cat, the bulk density of the polymer particles was 0.33 g / cc, and the melt flow rate was 0.01 g / 10 min or less. The results are shown in Table 1.

[Granulation] An antioxidant and a chlorine scavenger were added to the obtained polymer in the same manner as in Example 1 to prepare 1,3-bis- (t-butylperoxyisopropyl) benzene as an organic peroxide. After adding 0.08 parts by weight and mixing,
Pellets were obtained by extrusion at a cylinder temperature of 250 ° C.
“Injection molding” was performed in the same manner as in Example 1. The results are shown in Tables 1 and 2.

[0113]

[Table 1]

[0114]

[Table 2]

[Brief description of drawings]

FIG. 1 is a typical flow chart showing a method for producing a propylene-ethylene block copolymer of the present invention.

Continued front page    F-term (reference) 4J026 HA03 HA04 HA27 HA32 HA35                       HA48 HA49 HB03 HB04 HB32                       HB35 HB42 HB43                 4J028 AA01A AB01A AC05A BA02A                       BA02B BB01A BB01B BC15A                       BC15B BC16A BC16B BC17A                       BC17B BC19A BC19B BC34A                       BC34B CA16A CB12A CB14A                       CB22A CB27A CB42A CB44A                       DA01 DA02 DA03 DA05 DA06                       DB01A DB03A DB04A EB02                       EB04 EC01 EC02 FA01 FA02                       FA04 FA09 GA05 GA09 GA19                       GB01

Claims (2)

[Claims] 1. Obtained in the presence of a catalyst comprising [A] magnesium, titanium, and a titanium compound containing halogen as essential components, [B] an organoaluminum compound, and [C] t-butyl (ethyl) dimethoxysilane. A propylene-ethylene block copolymer having a composition of 100 to 95 mol% of propylene-based monomer units and 0 to 5 mol% of ethylene-based monomer units, and 1 to 40 wt% of a polypropylene component. %, A propylene-ethylene random copolymer component having 85 to 50 mol% of propylene-based monomer units and 15 to 50 mol% of ethylene-based monomer units is characterized by comprising 99 to 60 wt%. And a propylene-ethylene block copolymer. 2. The propylene-ethylene block copolymer according to claim 1, wherein the propylene-ethylene block copolymer has a titanium atom concentration of 5 ppm or less and a chlorine atom concentration of 30 ppm or less.