JPH0745530B2 - Method for producing thermoplastic elastomer - Google Patents

Description

TECHNICAL FIELD The present invention relates to a method for producing a thermoplastic elastomer having excellent tensile properties, low temperature properties and elastic properties by slurry polymerization.

In recent years, various thermoplastic elastomers have been developed as polymer materials that fill the boundary between plastic and rubber. Compared with conventional crosslinked rubber, they have better processing efficiency and the material can be reused for various purposes. It has come to be used for.

A thermoplastic elastomer is a polymer system in which a soft segment that is elastic under the conditions of use and a hard segment that is a pseudo-crosslinking point such as a crystal or hydrogen bond for preventing plastic deformation are appropriately present. For,
It is an elastomer designed to behave like a crosslinked rubber under use conditions and to behave like a general thermoplastic resin under processing conditions.

Among various thermoplastic elastomers, polyolefin-based thermoplastic elastomers are excellent in weather resistance, low temperature characteristics, heat resistance and electric characteristics, and have a small specific gravity and can be made lightweight, so that they can be used in the fields of automobiles and home appliances. It is mainly used for.

(Prior Art) This polyolefin-based thermoplastic elastomer is generally used for producing rubber such as ethylene-propylene rubber (hereinafter abbreviated as EPR) or ethylene-propylene terpolymer (hereinafter abbreviated as EPDM) and polypropylene, high-density polyethylene, etc. Manufactured by blending crystalline polyolefin components.

For example, JP-A-47-18943 discloses partially crosslinked EPR or EP.
Method of blending DM with polyolefin, Japanese Patent Publication No. 53-34
No. 210 discloses a method of crosslinking while mixing a rubber component and a plastic component, and Japanese Patent Publication No. 53-43981 discloses a method of blending a high molecular weight rubber component with a polyolefin without crosslinking. Also, based on the above technology,
Many patents have been filed to improve the physical properties by adding the third component.

However, most of the above-mentioned prior arts are for blending and cross-linking the rubber component and the plastic component, which are separately manufactured, respectively, so that a complicated blending and cross-linking step is required.

Further, EPR or EPDM, which is a main raw material for these polyolefin-based thermoplastic elastomers, is usually produced by solution polymerization using a vanadium compound-based catalyst having a good random copolymerization property of ethylene and propylene.

Therefore, the step of separating / drying the copolymer from the solvent is complicated, further the step of recovering / purifying the solvent is required, the polymerization activity of the catalyst at a high temperature is low, and the productivity is poor, and vanadium is used. Due to the reason that a decatalyzing step is necessary because the polymer has a large aging property,
EPR and EPDM are expensive. Further, as described above, the blending / crosslinking step may be required, so that the olefin-based thermoplastic elastomer as the final product must be expensive.

In order to improve such a conventional technique, a patent has recently been filed for producing a thermoplastic polyolefin-based elastomer in a slurry state using a titanium-based catalyst supporting titanium trichloride or magnesium chloride. For example, JP-A-55
-80418 uses a titanium trichloride-based catalyst, first an isotactic polypropylene segment and then a propylene-ethylene random copolymer are polymerized on the same catalyst.
A method for producing the produced propylene-ethylene block copolymer is disclosed. However, in such a polymerization method, it is difficult to effectively arrange the hard segment and the soft segment in the same molecule, and therefore the physical properties of the resulting polymer are insufficient as a thermoplastic elastomer. In JP-A-55-118909 and JP-A-118910, after prepolymerizing propylene using a magnesium chloride-supported titanium-based catalyst, a propylene-ethylene elastic copolymer of a propylene-ethylene elastic copolymer is substantially prepared in a propylene solvent under suspension conditions. A manufacturing method is disclosed. According to this copolymerization method, it is possible to obtain a copolymer having a high molecular weight, a large propylene chain microisotacticity, and excellent tensile strength and heat resistance. However, elastomeric properties such as hardness and permanent set are not yet satisfactory. There is also room for improvement in the bulk specific gravity of the polymer.

In JP-A-57-179207, a copolymer of ethylene and α-olefin is used to suppress the dissolution of the produced copolymer in a saturated or unsaturated hydrocarbon which is a polymerization solvent, using a magnesium chloride-supported titanium-based catalyst. A method for producing a thermoplastic elastomer which is carried out at a temperature of 50 ° C. or lower is also disclosed in JP-A-58-45209.
Also discloses a method for producing a thermoplastic elastomer in which the copolymerization of ethylene and α-olefin is carried out in a slurry state in an α-olefin solvent using a titanium-based catalyst supporting magnesium chloride. These have an ethylene content of 40
~ 90 wt%, ethylene crystallinity is 1 ~ 20%, the ethylene segment is a hard segment, and the elastomeric properties are considerably improved, but the balance between strength and flexibility is still sufficient. Is hard to say, and further improvement is desired.

As a method for improving these problems, Japanese Patent Application No.
In -102660, a specific organic transition metal compound-based catalyst is used, and a soft segment consisting of an ethylene-α-olefin random copolymer and a hard segment consisting of an ethylenic crystal and / or a propylene crystal are essentially in the same molecule. It illustrates a method for producing a polyolefin-based thermoplastic elastomer by arranging appropriately.
According to this production method, a copolymer having a high molecular weight, good particle shape, and excellent tensile strength and elastomeric properties can be obtained. However, although the thermoplastic elastomer obtained by this polymerization method has good extrusion moldability, there are some problems in the injection moldability of low hardness products. In addition, since the hard segment of the high hardness product is mostly composed of polyethylene crystal parts, there are some problems in heat resistance as compared with the polypropylene crystal part type. Further, particularly in the case of low hardness products, blocking may be observed depending on storage conditions.

(Problems to be Solved by the Invention) The inventors of the present invention have improved the above-mentioned various problems by providing a thermoplastic elastomer excellent in mechanical properties and processability and having good storage stability by a conventional compound. As a result of intensive research aimed at providing a method of producing only by a polymerization operation, the present invention has been achieved.

(Means for Solving Problems) The method for obtaining the thermoplastic elastomer in the present invention is a step of copolymerizing ethylene and propylene in the presence of a specific organic transition metal compound-based catalyst [I], followed by magnesium compound and titanium. Using a catalyst that gives a highly stereoregular polymer having an isotactic index of 90 or more formed from a titanium-based highly active highly stereoregular fixed catalyst component containing a compound and an electron donor compound as essential components and an organoaluminum compound It comprises a step [II] of substantially homopolymerizing propylene, and / or a step [III] of performing a copolymerization of propylene and ethylene using the same catalyst as in the step [II].

In the step [I], the ethylene content is 25 to 80% by weight, particularly preferably 35 to 70% by weight, and the melt flow index (JI
MFI according to SK-7210, 230 ° C, 10kg load condition, below MFI
10 g / 10 min or more, particularly preferably 5 g / 10 min or less ethylene-propylene copolymer is a step for producing 20 to 90% by weight of the final product.

When the ratio of the ethylene-propylene copolymer produced in the step [I] in the final product is less than the above,
Insufficient rubbery properties such as elasticity make it unsuitable for use as a thermoplastic elastomer. On the other hand, when the amount is more than this range, the effects of improving the processability, storage stability and heat resistance, which are the objects of the present invention, are insufficient.

Step [II] is a step of producing polypropylene having an isotactic index of 90 or more in an amount of 0 to 80% by weight of the final product. Here, the isotactic index is the content of the boiling n-heptane-insoluble matter expressed in% by weight. In this step, depending on the polymerization conditions, a small amount of ethylene may be unavoidable in the process, but if the ethylene content is small, it is not a problem and is included in polypropylene.

In the step [III], an ethylene-propylene copolymer having an ethylene content of 5 to 80% by weight is added to the final product of 0 to 80% by weight.
This is a manufacturing process.

The ethylene content in the final product thus produced is 10 to 70% by weight, particularly preferably 15 to 60% by weight.

The ethylene content in the propylene homopolymer and ethylene-propylene copolymer produced in steps [II] and [III] is 0 to 40% by weight, particularly preferably 0 to 30% by weight. In addition, the propylene homopolymer of the step [II] and the step [II]
There is no particular limitation on the ratio of the ethylene-propylene copolymer of [I], but when strength and heat resistance are required, the ratio of the step [II] is used, and when impact resistance and low temperature characteristics are required, It is preferable to increase the ratio of [III]. Next, the catalyst used in each step will be briefly described.

The specific organic transition metal compound catalyst used in the step [I] is at least one inorganic oxide selected from the group consisting of alumina, silica and silica-alumina in the form of porous fine particles subjected to hot water treatment and heat treatment. , The general formula RpMXq (where M is a transition metal of Group IVA of the periodic table, R is a hydrocarbon group or a substituted hydrocarbon group, X is a halogen, p and q are integers, and p is a metal of 2 to M). Maximum valence value, q is 0 to metal M
Represented by a value 2 less than the valence of the above), which is a transition metal catalyst obtained by catalytically reacting an organic transition metal compound represented by JP-A-60-76511, JP-A-60-76512, and JP-A-60-1354.
08, Japanese Patent Application No. 59-102660. To briefly describe this, at least one inorganic oxide selected from the group of alumina, silica and silica-alumina in the form of porous fine particles used in the preparation of a catalyst is, firstly, as a particle characteristic, a particle size of 10 to 1000 μm. ， Specific surface area 50〜1000m ² /
g, a pore volume of 0.2 to 3 ml / g, particularly preferably a particle size of 20 to ²⁰⁰ μ, a specific surface area of 100 to 400 m ² / g and a porous particulate solid having a pore volume of 0.3 to 2.5 ml / g. It is necessary to be.

In particular, in order to obtain a copolymer having a large bulk specific gravity and a good particle shape, it is preferable to use a solid having a uniform shape such as a sphere having a uniform particle diameter or a spherical shape.

Further, the above-mentioned alumina, silica and silica-alumina can be subjected to hot water treatment and heat treatment prior to use to impart a reactive hydroxyl group to the surface of the solid including the pores thereof. Γ-Alumina is preferable because it provides a highly active catalyst.

The hot water treatment applied to these inorganic oxides is carried out by a conventional method such as immersing the oxide in water heated to a temperature in the range of 40 to 100 ° C, especially distilled water, and boiling or stirring it.
It is contacted with hot water for 50 hours. Further, the heat treatment is to heat / remove the adsorbed water contained in the inorganic oxide after the hot water treatment, and the oxide is dehydrated / dried by a conventional method such as excess / solvent washing / heating. Is heated in a stream of an inert gas such as nitrogen gas at a temperature in the range of 100 to 1000 ° C., particularly preferably 300 to 600 ° C. for 1 to 24 hours.

When the organic transition metal compound is contact-reacted with the inorganic oxide subjected to the above treatment, it is preferable to add and react at least one compound selected from the group of organic aluminum compounds and organic magnesium compounds, if necessary. The organoaluminum compound has the general formula ▲
AlR ² ₃ ▼ (wherein R ² represents a hydrocarbon group having 1 to 10 carbon atoms or a substituted hydrocarbon group), or a reaction product of water and the above trialkylaluminum compound. Water-modified organoaluminum compounds can be used.

The water-denaturing reaction method is not particularly limited, and examples thereof include a method in which water is added to trialkylaluminum as a liquid, or dissolved in a solvent and added dropwise, or a method in which a catalytic reaction is performed by using dew or steam. Particularly preferred is a method of producing by carefully reacting with a compound containing water of crystallization such as copper sulfate pentahydrate. The reaction conditions for the above water modification are not particularly limited, but the molar ratio of water to the organoaluminum compound is preferably 0.1: 1 to 2
5: 1 is particularly preferably 0.3: 1 to 2: 1, and the reaction temperature is preferably −80 to 100 ° C., particularly preferably −20 to 50.
The treatment is carried out at 0 ° C. for 5 minutes to 100 hours, particularly preferably 1 to 50 hours.

The structure of the water-modified organoaluminum compound obtained by such a reaction is very complicated, and probably the general formula Linear aluminoxane and general formula Cyclic aluminoxane (R ² is a hydrocarbon group, n is 1 to
(Integer up to 50).

The organomagnesium compound is represented by the general formula R ³ MgR ⁴
(Wherein R ³ and R ⁴ represent the same or different hydrocarbon groups having 1 to 20 carbon atoms or substituted hydrocarbon groups), and specific examples include dimethylmagnesium and diethylmagnesium. , Divinyl magnesium, ethyl isopropyl magnesium, di-n-propyl magnesium, diisopropyl magnesium, di-n
-Butylmagnesium, n-butylethylmagnesium, n
-Butyl-sec-butyl magnesium, di-t-butyl magnesium, di-sec-butyl magnesium, n-butyl-t-butyl magnesium, dicyclopentadienyl magnesium, diphenyl magnesium, di-n-hexyl magnesium, n- Hexylethyl magnesium, dihexynyl magnesium, dicyclohexyl magnesium, dibenzyl magnesium, di-n-octyl magnesium and the like can be mentioned.

The above-mentioned organoaluminum compound and organomagnesium compound are used for improving the activity of the catalyst used in the present invention and for improving the particle shape of the produced polymer.

The organic transition metal compound used in the present invention has the general formula RpMXq
(In the formula, M is a transition metal of Group IVA of the periodic table, R ¹ is a hydrocarbon group or a substituted hydrocarbon group, X is a halogen, p and q are integers, and p is the highest valence of the metal M. Value, q is 0
An organic transition metal compound represented by (representing a value smaller than the valence of the metal M by 2), which exhibits an appropriate random copolymerizability, is specifically exemplified by tetrapentylzirconium, tetrabenzyltitanium, and tetrabenzylhafnium. , Tetra (trimethylsilylmethylene) zirconium and the like. Random copolymerization performance is too high organic transition metal compounds, such as tetraneophyll zirconium, when these are used in slurry polymerization, the resulting polymer becomes amorphous, the amount of dissolution of the polymer in the solvent increases, In addition to being unable to obtain a good suspension state, problems such as adhesion between polymer particles and scale due to the tackiness of the polymer particles occur.
In addition, there is a problem in morphology in the gas phase polymerization, and the tensile strength of the produced polymer becomes low, which is not preferable.

In the present invention, the inorganic oxide is at least 1 selected from organic aluminum compounds and organic magnesium compounds.
The method of catalytically reacting the compound of the species with the organic transition metal compound is a method in which an organoaluminum compound or the like is suspended in a state in which the inorganic oxide subjected to the hot water treatment and the heat treatment as described above is suspended in the organic solvent. A conventional method such as adding and stirring a solution dissolved in an organic solvent is used. The order of addition of these organometallic compounds is not particularly limited, but it is preferable that the organoaluminum compound or the organomagnesium compound is added and reacted first, and then the organotransition metal compound is added and reacted in terms of contact activity, and these are added simultaneously. What is made to react, or what made the said order reverse can also be used.

The solvent for suspending the above inorganic oxide is inert and must be dehydrated and deoxygenated.

Examples of the inert solvent include aromatic hydrocarbons such as benzene, toluene and xylene, unsaturated aliphatic hydrocarbons such as n-pentane, n-hexasi and n-heptane, and alicyclic hydrocarbons such as cyclohexane and methylcyclohexane. Used. Further, these solvents can also be used as a solvent for dissolving the above organometallic compound.

The amount of the organometallic compound to be catalytically reacted with the above inorganic oxide is, in the case of the organic transition metal compound, 0.05 to 1.0 mmol as a transition metal atom, particularly preferably 0.1 to 0.5 mmol per 1 g of the obtained catalyst. Used in. Further, regarding the organoaluminum compound or the organomagnesium compound, the atomic ratio of Al and the transition metal is 0.0 as a mutual relationship between these organometallic compounds contained in the obtained catalyst.
5: 1 to 100: 1, particularly preferably 0.1: 1 to 25: 1, the atomic ratio of Mg to the transition metal is 0.05: 1 to 50: 1, particularly preferably 0.1: 1 to
It is suitable to add it in the range of 5: 1.

As the conditions for the catalytic reaction of these organometallic compounds, a reaction temperature of 0 to 40 ° C. and a reaction time of 10 minutes to 24 hours are usually used, but in particular, many organic transition metal compounds are thermally unstable. Therefore, when using such an unstable compound, it is necessary to keep the reaction temperature sufficiently low to prevent decomposition.

Next, as the catalysts used in the steps [II] and [III], there may be mentioned all the highly active and highly stereoregular solid catalysts having a regular shape and containing an organomagnesium compound, a titanium compound and an electron donor as essential components.

Regarding the method for producing this highly active and highly stereoregular solid catalyst component, for example, JP-A-55-135103, 55-145708, 55
-152710, 56-811, 56-81314, 56-98206, 57-5
9916, JP-B-58-40565, and JP-A-58-40566.

The method of JP-A-59-96107 will be briefly described below as an example.

That is, in the presence of a support obtained by treating silica, aluminami or silica-alumina with an organoaluminum compound, the general formula MgR ¹ R ² (R ¹ and R ² are the same or different hydrocarbon groups having 1 to 20 carbon atoms) The solid catalyst component (A) obtained by catalytically reacting a solid product obtained by catalytically reacting an organomagnesium compound represented by the formula), an electron donor, and a halogenated hydrocarbon with an organic compound of phenols and a titanium halide. And a organoaluminum compound (B).

Here, the solid catalyst component (A) is manufactured as follows.

Silica heated and treated with organoaluminum compounds,
An organomagnesium compound (b), an electron donor (c) and a halogenated hydrocarbon (d) are mixed into a system in which alumina or a silica-alumina carrier (a) is suspended in an inert solvent,
Catalytic reaction was carried out, and further, the produced solid product was catalytically reacted with an organic compound (e) of phenols and a titanium halogen compound (f) to obtain a titanium-containing solid catalyst component. (B),
The mixing of the three components (c) and (e) is carried out in an appropriate order or by adding them simultaneously. In terms of handling of the organomagnesium compound, it is added to the reaction system containing the organomagnesium compound and the electron donor. It is desirable to add halogenated hydrocarbons.

In these methods, each component is diluted with an inert solvent,
Alternatively, it can be dissolved without dilution.

Here, the silica, alumina or silica-alumina carrier (a) preferably has a narrow particle size distribution, and the particle shape thereof is preferably a regular shape such as spherical or elliptic spherical. The particle size is 5 to 1000μ, the surface area is 50 to 1000m ² / g, and the pore volume is 0.2 to 3m.
L / g is preferable. Particularly preferably, those having an average particle size of 20 to ²⁰⁰ μ, a surface area of 100 to 400 m ² / g and a pore volume of 1 to 25 ml / g are used.

Silica, alumina or silica-alumina carriers are suitable for use at temperatures in the range 100 to 1000 ° C., particularly preferably 200.
After drying at a temperature of ~ 600 ℃, 3 ~ 15% by weight to the carrier
And then treated with the organoaluminum compound. The organoaluminum compound used in the treatment may be the same as or different from the organoaluminum compound (B) used in the polymerization.

Such modification of the carrier is effective in improving activity, stereoregularity and polymer shape.

The organomagnesium compound (b) has the general formula MgR ¹ R ² (R ¹ , R
² represents the same or different hydrocarbon group having 1 to 20 carbon atoms), and specific examples include dimethyl magnesium, diethyl magnesium, divinyl magnesium, ethyl isopropyl magnesium, di-
n-propyl magnesium, diisopropyl magnesium, di-n-butyl magnesium, n-butyl ethyl magnesium, n-butyl-sec-butyl magnesium, di-
t-butyl magnesium, di-sec-butyl magnesium, n-butyl-t-butyl magnesium, dicyclopentadienyl magnesium, diphenyl magnesium, di-n-hexyl magnesium, n-hexyl ethyl magnesium, dihexynyl magnesium, dicyclohexyl Examples thereof include magnesium, dibenzyl magnesium, di-n-octyl magnesium and the like.

Among these organomagnesium compounds, n-butylethylmagnesium is particularly preferable.

As the electron donor (c), a nitrogen-containing compound selected from amine and amide, a phosphorus-containing compound selected from phosphine, phosphoric acid ester and phosphoric acid amide, an oxygen-containing compound selected from ketone, ether, ester and aldehyde A compound is used. Of these compounds, organic acid esters, particularly lower alkyl esters of aromatic carboxylic acids, are preferred. Specifically, methyl benzoate, ethyl benzoate, -n-propyl benzoate, -n-butyl benzoate, isobutyl benzoate, -n-octyl benzoate, methyl toluate, ethyl toluate, toluic acid-n. −
Butyl, isobutyl toluate, toluic acid-n-octyl, methyl anisate, ethyl anisate, anisic acid-n
-Propyl and the like can be mentioned. Particularly preferred are methyl benzoate, ethyl benzoate, methyl anisate and ethyl toluate.

Examples of the halogenated hydrocarbon (d) include dichloroethane,
Dichloropropane, dichlorobutane, chloroform and carbon tetrachloride are preferable, and carbon tetrachloride is particularly preferable.

Examples of organic compounds (e) of phenols include phenol, cresol, chlorophenol, bromophenol, nitrophenol, 2,4-dinitrophenol, 2,4,6.
-Trichlorophenol, 2,4,6-tribromophenol and the like are preferable, and phenol and cresol are particularly preferable.

Examples of the titanium halide (f) include titanium tetrachloride, titanium tetrabromide, titanium tetraiodide, methoxytitanium trichloride, ethoxytitanium trichloride, propoxytitanium trichloride, butoxytitanium trichloride, dibutoxytitanium dichloride, tributoxy. Titanium halides such as monochloride, and alkoxy halides may be used alone or as a mixture. Particularly, titanium tetrachloride is preferable.

Examples of the inert solvent include aromatic hydrocarbons such as benzene, toluene and xylene, saturated aliphatic hydrocarbons such as n-pentane, n-hexane, n-heptane and n-octane, and alicyclic compounds such as cyclohexane and methylcyclohexane. Hydrocarbons are used.

The amount ratio of the above components (a) to (f) may be any amount ratio as long as the effects of the present invention can be obtained, but the composition of the prepared solid catalyst component is preferably as follows.

Silica, alumina or silica-alumina carrier 30 to 90% by weight, preferably 35 to 80% by weight, titanium 0.5 to 8% by weight, preferably 1 to 5% by weight, magnesium 2 to 20% by weight, preferably 3 to 12% by weight %, Halogen 5 to 60% by weight,
Preferably 10-45% by weight, electron donor compound 0.5-20% by weight, preferably 1-15% by weight.

The reaction temperature is not particularly limited, but it is preferably carried out at 40 ° C. or higher in order to proceed the reaction.

The organoaluminum compound (B) has a general formula of AlR ³ _n X.
A compound represented by _3-n (R ³ is an alkyl group having 1 to 20 carbon atoms, X is a halogen atom, and n is a number of 1 to 3) is used alone or as a mixture.

Specific examples of these compounds are triethyl aluminum, tripropyl aluminum, triisobutyl aluminum, trihexyl aluminum, trioctyl aluminum, diethyl aluminum chloride, di-n.
-Propyl aluminum chloride, diisobutyl aluminum chloride, methyl aluminum sesquichloride, ethyl aluminum sesquichloride, ethyl aluminum dichloride and the like. Particularly preferred is triethylaluminum.

The amount of the organoaluminum compound used is converted to aluminum atoms of the organoaluminum compound per titanium atom contained in the titanium catalyst component, and the Al / Ti molar ratio is 0.01.
~ 200, preferably 1-100.

The electron donor in weight may be the same as or different from the electron donor used in the preparation of the catalyst.
The electron donor is used in an amount of 0 to 1.0 mol, preferably 0.05 to 0.5 mol, per 1 mol of the organoaluminum compound.

As the polymerization or copolymerization method carried out in the steps [I], [II] and [III], various polymerizations such as slurry polymerization using liquefied propylene as a polymerization solution, gas phase polymerization in the absence of a solvent and combinations thereof Method is possible. As the polymerization type, a batch type and a continuous type can be carried out.

The polymerization temperature is room temperature to 200 ° C, preferably 40 to 100 ° C, and the pressure is preferably atmospheric pressure to 100 atm. Further, it is possible to adjust the molecular weight of the polymer produced by allowing hydrogen to be present in the polymerization system.

An organic transition metal compound-based catalyst used in the step [I] and [II],
Since the titanium-based highly active and highly stereoregular catalysts used in [III] have different catalyst systems, the properties of polymers produced under the same conditions are also greatly different. In order for the final product to have excellent properties as a thermoplastic elastomer, it is essential to set the polymerization conditions according to the respective catalyst systems, and therefore it is preferable that these two catalysts do not have polymerization activity at the same time.
For example, a polymer produced by an organic transition metal compound-based catalyst has a poor particle shape at a low ethylene content, and thus the process [I
It is difficult to produce under the polymerization conditions of I] and [III]. On the other hand, the polymer from which the titanium-based highly active and highly stereoregular catalyst is produced is The copolymer having a remarkably low molecular weight and produced under the polymerization conditions of step [I] has a very poor particle shape and is difficult to produce.

In the present invention, as a result of various studies, the above problems could be solved by using the above two kinds of catalyst systems in a specific order.

That is, first, in step [I], polymerization is carried out using an organic transition metal compound-based catalyst, and then titanium-based highly active and highly stereoregular contact is added to carry out steps [II] and [II].
The activity of the organic transition metal compound-based catalyst in I] is reduced to such an extent that there is no practical problem.

The steps [II] and [III] may be performed in the reverse order without any problem.

The copolymer obtainable by the present invention has good fluidity, a large bulk specific gravity, and good physical properties and processability as a thermoplastic elastomer.

This copolymer is used for other polymer compounds such as polypropylene, high density polyethylene, medium density polyethylene, low density polyethylene, linear low density polyethylene, ethylene-
It can be used as a mixture with vinyl acetate copolymer, poly-1-butene, petroleum resin, wax, natural rubber, synthetic rubber and the like. In addition, various stabilizers, antioxidants, UV absorbers,
Antistatic agents, lubricants, softeners, plasticizers, pigments, inorganic and organic fillers can be added.

(Examples) Hereinafter, the present invention will be described in more detail with reference to Examples and Comparative Examples, but the present invention is not limited to these Examples. The method of measuring various data in the examples is as follows.

Ethylene content; by infrared absorption spectroscopy.

MFI; 230 according to JIS K-7210, except as otherwise noted
℃, 216kg load.

Hardness: Based on JIS K-6301.

Tensile test; based on JIS K-6301.

Permanent elongation: 100% elongation according to JIS K-6301, 10
Hold for a minute, and after 10 minutes of return, the permanent elongation.

Example 1 [Preparation of organic transition metal compound-based catalyst] Production of water-modified organoaluminum compound 37.5 g (0.15 mol) of fine powder CuSO ₄ .5H ₂ O was added to 100 m of toluene.
50 ml of trimethylaluminum at 20 ℃ with stirring.
A mixed solution of 1 (0.52 mol) and 150 ml of toluene was gradually added dropwise. After the dropping was completed, the reaction was continued at 20 ° C. for 48 hours. Next, after passing the reaction solution and removing solid copper sulfate, 2 mmHg
17g (0.29mo) by removing toluene and unreacted trimethylaluminum by vacuum distillation at 35 ℃.
l) of methylaluminoxane was obtained.

Preparation of catalyst High-purity γ-alumina (Catalyst Kasei ACP-1, average particle size about 60
μ, specific surface area about 300 m ² / g, pore volume 0.7 ml / g) 500 g, about 9
After stirring in hot water 2 at 5 ° C. for 3 hours, water was removed.
Further, this operation was repeated 10 times, followed by washing with acetone and drying. This was heated in a dry nitrogen stream at 450 ° C. for 6 hours to remove adsorbed water.

0.5 g of this alumina was suspended in 4 ml of n-hexane, and dissolved in 1 ml of toluene. Methylaluminoxane 5.8
mg (0.1 mmol aluminum unit) was added. After stirring this mixture at room temperature for 30 minutes, 0.6 ml of a 0.16 M solution of tetrabenzylzirconium dissolved in toluene was added,
Further, the mixture was stirred at room temperature for 30 minutes. Neither Zr nor Al was detected in the liquid phase.

The solid catalyst thus prepared was calculated from the adsorption amount of Zr and Al, and was found to be 0.19 mmol / g zirconium and 0.2 m
It contained mol / g of aluminum.

[Preparation of titanium-based solid catalyst component]

Into a 200 ml four-necked frost, 50 ml of dehydrated n-hexane, 6 g of silica gel (surface area of about 300 m ² / g, average particle size of about 50 μm, calcined at 540 ° C. for 6 hours) and 3 ml of triethylaluminum were charged and stirred for 1 hour. This is thoroughly washed with dehydrated n-hexane and then vacuum dried. Dehydrated n-heptane 50 to the produced solid
ml, n-butylethylmagnesium in heptane solution (manufactured by Toyo Stoufer, 20 wt%) 25 ml, and the solution temperature was adjusted to 80
The temperature was raised to ° C. After reaching 80 ° C., 2 ml of ethyl benzoate and 20 ml of carbon tetrachloride were gradually added dropwise with stirring. After completion of dropping, the mixture was further stirred for 2 hours at 80 ° C., and then p-cresol 1.
A heptane solution containing 1 g was added dropwise with stirring. After the completion of dropping, the mixture was stirred at 80 ° C. for 2 hours. Dehydration excluding solution part
-Washed thoroughly with hexane and vacuum dried at room temperature. To this, 50 ml of titanium tetrachloride was added and dried at 100 ° C for 2 hours. The solid product treated with titanium tetrachloride was passed through, thoroughly washed with dehydrated n-hexane, and vacuum dried at room temperature to obtain a titanium-containing solid catalyst component. As a result of analysis of this solid catalyst, it was found that it contained 2.99 wt% titanium, 5.0 wt% magnesium, and 21.7 wt% chlorine.

As a result of homopolymerization of propylene in the following polymerization steps using this catalyst, all of the obtained polypropylenes had an isotactic index of 90 or more.

〔polymerization〕

A stainless steel autoclave No. 2 equipped with a stirrer was vacuum degassed and purged with nitrogen, and then 500 g of propylene was charged. After heating the system and charging ethylene to an ethylene partial pressure of 2.5 kg / cm ² at 55 ° C, the organic transition metal compound catalyst slurry prepared by the above method was added to the autoclave by a pressure equalizer. After that, ethylene is continuously supplied, and the temperature is maintained at 60 ℃ and the ethylene concentration is maintained at 12mol%.
Copolymerization was carried out for a time. Unreacted monomers were removed to obtain a substantially dry copolymer powder (step [I]).

The titanium-based solid catalyst 30 mg, triethylaluminum 1.4
After adding a hexane slurry solution of mmol and ethyl benzoate 0.4 mmol, hydrogen was charged at a partial pressure of 0.2 kg / cm ^2, and propylene gas was continuously supplied at a temperature of 70 ° C.
Polymerization was carried out at a total pressure of 15 kg / cm ² for 1 hour (step [II]). Next, a mixed gas of ethylene and propylene was continuously supplied so that the ethylene concentration in the autoclave would be 10 mol%, and polymerization was carried out at a temperature of 70 ° C and a total pressure of 15 kg / cm ² for 0.5 hour (step [I
II]).

The obtained copolymer had good fluidity and the yield was 210 g, M
The FI was 0.96 g / 10 min and the ethylene content was 22% by weight. Various physical properties of the obtained copolymer are shown in Table 2.

Examples 2 to 6 Example 1 except that the polymerization conditions were changed as shown in Table 1.
The catalyst was prepared and copolymerized in the same manner as in. The polymerization results are shown in Table 1, and the physical properties of the resulting copolymer are shown in Table 2. In Example 6, the copolymerization in step [III] was carried out in two stages under the conditions shown in Table 1.

Comparative Example 1 Copolymerization was carried out by reversing the order of addition of the organic transition metal compound catalyst and the titanium solid catalyst.

Propylene 500g in autoclave as in Example 1
After charging, the same amount of titanium-based solid catalyst, triethylaluminum, and ethyl benzoate as in Example 1 was added by a pressure equalizer, and polymerization was carried out at a temperature of 70 ° C. for 1 hour.

Next, the same amount of the organic transition metal compound catalyst as in Example 1 was added by a pressure equalizer, and ethylene was continuously supplied to carry out copolymerization while maintaining the temperature at 60 ° C. and the ethylene temperature at 12 mol%. The polymerization was stopped 0.7 hours after the start of the polymerization because the stirring became unsuccessful.

The product was blocked.

Comparative Example 2 In the same manner as in Example 4, only the step [1] was performed to terminate the polymerization. The yield of the obtained copolymer is 117g, MFI (230 ℃, 10kg
Load) 0.12 g / 10 min, ethylene content was 39% by weight.
Further, the particle shape of the copolymer and the fluidity immediately after the polymerization were good, but after standing for 3 days, some blocking was observed and the fluidity was lowered.

(Effects of the Invention) As is apparent from the above description, according to the present invention, a thermoplastic elastomer having excellent mechanical properties and processability and good storage stability can be produced only by a polymerization operation.

[Brief description of drawings]

FIG. 1 is a flow chart showing the catalyst preparation process.

Claims (1)

[Claims] 1. A group of an organoaluminum compound and an organomagnesium compound in addition to at least one inorganic oxide selected from the group of alumina, silica and silica-alumina in the form of porous fine particles which have been subjected to hot water treatment and heat treatment. At least one compound selected from the group consisting of RpMXq (wherein M is a transition metal of Group IVA of the periodic table, R is a hydrocarbon group or a substituted hydrocarbon group, X is halogen, p and q is an integer, p is a value of the highest valence of 2 to metal M, q is a value of 2 less than the valence of 0 to metal M), a transition metal obtained by catalytically reacting an organic transition metal compound A step of copolymerizing ethylene and propylene in the presence of a catalyst to contain 25 to 80% by weight of copolymerized ethylene in the resulting polymer [I], followed by organomagnesium compound, titanium compound and Propylene was prepared using a catalyst that gives a highly stereoregular polymer with an isotactic index of 90 or more formed from a titanium-based highly active and highly stereoregular solid catalyst component containing an electron donor compound as an essential component and an organoaluminum compound. Substantially homopolymerizing step [II] and / or copolymerizing propylene and ethylene using the same catalyst as in step [II], and containing 5 to 80% by weight of copolymerized ethylene in the produced polymer. A method for producing a thermoplastic elastomer, which comprises the step [III] of