JPH0674295B2 - Method for producing thermoplastic elastomer - Google Patents

Description

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.

The thermoplastic elastomer is a polymer system in which a soft segment showing elasticity under the use conditions and a hard segment serving as a pseudo-crosslinking point such as a crystal or hydrogen bond for preventing plastic deformation are appropriately present. Therefore, 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 electrical characteristics, have a small specific gravity, and can be reduced in weight. It is mainly used for.

This thermoplastic polyolefin-based elastomer is generally prepared by blending a rubber component such as ethylene-propylene rubber (hereinafter abbreviated as EPR) or ethylene-propylene terpolymer (hereinafter abbreviated as EPDM) with a crystalline polyolefin component such as polypropylene or high-density polyethylene. Being manufactured.

For example, JP-A-47-18943 discloses partially crosslinked EPR or EP.
Method for blending DM with polyolefin, JP-A-48-26
No. 838 discloses a method of crosslinking while mixing a rubber component and a plastic component, and JP-A-49-53938 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 conventional techniques are to blend and modify a rubber component and a plastic component, which are separately produced. In such a case, since the soft segment and the hard segment are appropriately deviated from the ideal type of the thermoplastic elastomer in which they are appropriately present in the same molecule, when compared with a crosslinked rubber in terms of properties as an elastomer, for example, strength and flexibility There are many problems such as poor balance of sex.

Further, EPR or EPDM, which is the main raw material of 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 / modifying step may be required, so that the olefin-based thermoplastic elastomer as the final product is inevitably 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 not possible to arrange the hard segment and the soft segment in the same molecule, and most of the products are a mixture of isotactic polypropylene and propylene-ethylene random copolymer. The physical properties of the 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% by weight, ethylene crystallinity is 1 ~ 20%, the ethylene segment is used as a hard segment, and the elastomeric property is considerably improved, but the balance between strength and flexibility is still insufficient. It is hard to say and further improvement is desired.

On the other hand, ethylene and α using a transition metal catalyst which is a reaction product of an inorganic oxide and an organic transition metal compound as a polymerization catalyst.
There is a method for producing an elastic copolymer of olefin. For example, in JP-A-55-147511, an amorphous elastomeric copolymer of ethylene and .alpha.-olefin made in an organic diluent in which most of the monomer and polymer products are soluble under the reaction conditions. Is disclosed. See also
-8004 discloses a method for producing an amorphous elastomer using tetraneophile zirconium which is particularly excellent in random copolymerizability as an organic transition metal compound. However, these inventions are not intended for the production of thermoplastic elastomers, but for the production of mere elastomers.
Also, the shape of the polymer is not good. JP 54-40889 A
A method for producing a high molecular weight, low stereoregular elastic polypropylene is disclosed. This is intended for the production of thermoplastic elastomers, but since it has a high propylene content, it has problems in low temperature properties and impact resilience.

The present inventors have improved these problems and provided a method for producing a polyolefin-based thermoplastic elastomer having a good polymer particle shape, a large bulk specific gravity, and excellent tensile properties and elastomeric properties. As a result of intensive research aimed at, the present invention has been achieved.

That is, the present invention relates to a porous fine particle-shaped inorganic oxide which has been subjected to hot water treatment and heat treatment, and has a general formula P ¹ _p MX _q (wherein M is a transition metal of Group IVA to VIA of the periodic table). , R ¹ is a hydrocarbon group or a substituted hydrocarbon group, X is a halogen, p and q are integers, p is a value of the maximum valence of the metal M, and q is 0.
(Representing a value 2 less than the valence of the metal M) in the presence of a transition metal catalyst obtained by catalytically reacting an organic transition metal compound represented by the formula (3), which is a comonomer having 3 to 12 carbon atoms.
A method for producing a thermoplastic elastomer, characterized in that olefin is used as a polymerization solvent, ethylene and the α-olefin are subjected to slurry polymerization, and 25 to 85% by weight of copolymerized ethylene is contained in the produced polymer. .

According to the present invention, ethylene-α-in essentially the same molecule.
A soft segment composed of an olefin random copolymer and a hard segment composed of an ethylenic crystal and / or a propylene crystal can be appropriately arranged, and a thermoplastic elastomer can be produced all at once by polymerization without blending / modifying operations. It has become possible.

Examples of the porous particulate inorganic oxide used in the present invention include:
First of all, the particle characteristics are particle size 10-1000μ, specific surface area 50
~ 1000 m ² / g, pore volume 0.2 ~ 3 ml / g, particularly preferably 20 ~ 2
00μ particle size, 100-400m ² / g specific surface area and 0.3-2.5ml /
It must be a porous, particulate solid with a pore volume of g.

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 spherical shape or an elliptic spherical shape with a uniform particle diameter.

Furthermore, as the above-mentioned inorganic oxide, it is necessary to give a reactive hydroxyl group to the surface of the solid including the pores by subjecting it to hot water treatment and heat treatment prior to use. is there. Examples of the inorganic oxide having the above properties include alumina and silica, and γ-alumina is particularly 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 and remove the adsorbed water contained in the inorganic oxide after the hot water treatment, and the oxide is dehydrated and dried by a conventional method such as excess x solvent washing and 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 an organic transition metal compound is contact-reacted with the inorganic oxide that has been subjected to the above treatment, it is preferable to add and react an organoaluminum compound as necessary. As the organoaluminum compound, a water-modified organoaluminum compound which is a reaction product of water and the trialkylaluminum compound can be used.

The water-denaturing reaction method is not particularly limited, and may be a method in which water is added to the trialkylaluminum as a liquid, or dissolved in a solvent and added dropwise, or a method in which the reaction is carried out in the form of mist 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, dihexyl 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 P ¹ _p MX _q
(In the formula, M is a transition metal of Group IVA to VIA 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 a maximum atom of 2 to M. A valence value, q represents 0 to 2 less than the valence of the metal M), and an organic transition metal compound having an appropriate random copolymerizability is preferable. Specifically, tetrabenzyl zirconium, Tetrabenzyl titanium, tetrabenzyl hafnium, tetra (trimethylsilylmethylene)
Examples thereof include zirconium. However, an organic transition metal compound having too high random copolymerization performance, for example, tetraneophyll zirconium, when these are used, the resulting polymer becomes amorphous, and the amount of the polymer dissolved in the solvent increases, which is good. In addition to not being able to maintain a stable suspension state, problems such as adhesion between polymer particles due to adhesiveness of polymer particles and scale occur, and the tensile strength of the produced polymer also becomes low. It is not used because it will not meet the required performance as

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 in terms of catalytic activity that the organoaluminum compound or the organomagnesium compound is added and reacted first, and then the organotransition metal compound is added, and these are also 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.

As the inert solvent, aromatic hydrocarbons such as benzene, toluene and xylene, saturated aliphatic hydrocarbons such as n-pentane, n-hexane and n-heptane, and alicyclic hydrocarbons such as cyclohexane and methylcyclohexane are used. To be 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.

Using the transition metal catalyst thus obtained, in order to produce an olefin-based thermoplastic elastomer having a large bulk specific gravity and good particle shape, the α-olefin comonomer is used as a polymerization solvent, and the resulting polymer is used. It is necessary to carry out polymerization under the condition of suspension of so-called slurry polymerization. The term "suspending condition" as used herein means that the amount of the produced polymer dissolved in the polymerization solvent is about 10% by weight or less,
When the amount of dissolution is more than this, adhesion between polymer particles,
The scale adheres to the wall surface of the polymerization tank and the formation of a string-like polymer occurs, which makes it difficult to obtain a copolymer having a high bulk specific gravity. Further, the particles often adhere to each other even after the copolymer is isolated, or the biting becomes insufficient even when the particles are molded through an extruder. The amount of the produced polymer dissolved in the polymerization solvent is mainly determined by factors such as the composition and molecular weight of the produced copolymer, the type of the polymerization solvent, and the polymerization temperature.

Each factor will be described in detail below.

In the production method of the present invention, a copolymer as a thermoplastic elastomer composed of ethylene and α-olefin is obtained, and a copolymer of particular interest is the inclusion of the copolymerized ethylene in the copolymer. The amount is in the range 25 to 85% by weight, particularly preferably 30 to 80% by weight.

If the ethylene content is higher than the above range, there is no problem in carrying out the polymerization reaction, but the hardness of the product is high, and the permanent set is large, so that it is difficult to use it in applications requiring elasticity. On the other hand, when the ethylene content is lower than the above range, the amount of the copolymer dissolved in the polymerization solvent is large, a good slurry state cannot be maintained, the particle shape of the polymer is poor, and the bulk specific gravity is low. I can only get things. Moreover, it is not preferable as a thermoplastic elastomer because it has tackiness and poor low-temperature properties.

In order to obtain a copolymer containing ethylene in the above range, the ethylene partial pressure in the polymerization system may be changed depending on the polymerization conditions.
It is preferably about 0.5 to ²⁰ kg / cm ² .

The α-olefin used as a comonomer in the present invention is an aliphatic unsaturated hydrocarbon having a double bond at the terminal and having 3 to 12 carbon atoms, and specific examples thereof include propylene, butene-1,4- Methylpentene-1, hexene-1
And octene-1. Of these, propylene is particularly preferable from the viewpoint of polymerization activity and price, but these α-olefins may be used alone or in combination of two or more. If desired, a small amount of polyenes such as dienes and trienes may be added to the copolymerization component.

Further, for these catalyst systems, pre-polymerization under conditions such that an ethylene polymer or a copolymer having a high ethylene content is produced is particularly effective in obtaining a copolymer having a low ethylene content. It is effective for increasing the bulk specific gravity without deteriorating the physical properties.

According to the present invention, it is possible to easily produce a copolymer having an extremely large molecular weight, and the molecular weight can be adjusted to a desired one by using a molecular weight regulator such as hydrogen. . Melt flow index is a conventional index of molecular weight of the desired molecular weight range of the copolymer (according to JIS K-7210, 230 ℃, under 10kg load conditions,
It is 10 g / 10 minutes or less, particularly preferably 5 g / 10 minutes or less, as shown by MFI). If the MFI is larger than this, the molecular weight of the copolymer is low, the amount dissolved in the polymerization solvent is large, it becomes difficult to maintain good suspension conditions, the particle shape is poor, and the bulk specific gravity is small, and It is not preferable because physical properties such as tensile strength and permanent set are remarkably deteriorated.

Use of an inert hydrocarbon used in ordinary slurry polymerization as a polymerization solvent makes it difficult to maintain good suspension conditions because the amount of the produced polymer dissolved in the solvent increases in high temperature polymerization. However, the low temperature polymerization is not preferable in any case due to a decrease in the activity of the catalyst and an increase in the process cost for removing the reaction heat.

Furthermore, a solvent recovery / purification process is also required.

On the other hand, when the α-olefin itself which is a comonomer is used as the polymerization solvent, unlike the case where the above-mentioned inert hydrocarbon is used, the peculiar behavior that the dissolved amount of the produced polymer is decreased by high temperature polymerization Was found to show. That is, the polymerization temperature is preferably selected in the range of 35 to 90 ° C, particularly 45 to 80 ° C. In this temperature range, it is possible to maintain good suspension conditions and at the same time improve production efficiency.

As described above, the polymerization solvent is α- which is a comonomer.
Although an olefin is used, there is no problem even if the normally used inert hydrocarbon is contained in the liquid phase of the solvent in an amount of about 10% by volume or less.

The present invention is obtained by reacting an inorganic oxide in the form of porous fine particles with a reactive group by hot water treatment or the like, and reacting it with an organometallic compound that imparts activity improvement, particle shape improvement and appropriate random copolymerizability. Using the catalyst thus obtained, an ethylene-α-olefin random copolymer having an ethylene content of 25 to 85% by weight is obtained by using the comonomer α-olefin itself as a polymerization solvent. It is possible to obtain a thermoplastic elastomer having a good particle shape, a large bulk specific gravity, and good physical properties and processability at a high slurry concentration by the effects of the respective properties acting comprehensively. For example, polymerization solvent liquid phase 1
It is possible to carry out continuous polymerization for a long time with a slurry concentration of the produced polymer of about 200 to 600 g. After completion of the polymerization, by means such as flash removal of excess or unreacted α-olefin,
The target copolymer can be easily isolated. The obtained copolymer has a spherical shape with a uniform particle size and can be melt-molded in the same manner as a normal polyolefin.

This copolymer is used for other polymer compounds such as PP, HDPE, MD.
It can be used by mixing with PE, LDPE, LLDPE, EVA, poly-1-butene, petroleum resin, wax, natural rubber, synthetic rubber and the like. Further, various stabilizers, antioxidants, ultraviolet absorbers, antistatic agents, lubricants, softeners, plasticizers, pigments, inorganic and organic fillers can be added.

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: According to JIS K7210, 230 ° C, 10kg load.

Bulk specific gravity; based on JIS K-6721.

Hardness; based on JIS K-6301.

Torsional rigidity; based on JIS K-6301.

Tensile test; based on JIS K-6301.

Impact resilience; based on JIS K-6301.

Permanent elongation: According to JIS K-6301, 100% elongation, holding for 10 minutes, and after returning for 10 minutes, the permanent elongation.

Low temperature embrittlement temperature; based on JIS K-6301.

Example 1 Production of Water-Modified Organoaluminum Compound 37.5 g (0.15 mol) of finely powdered CuSO ₄ .5H ₂ O was added to 100 parts of toluene.
suspended in 20 ml of trimethylaluminum at 20 ℃ with stirring.
A mixed solution of 0.5 ml (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 about 0.7 ml / g) 500 g,
After stirring in hot water 2 at about 95 ° C. for 3 hours, water was removed. Further, this operation was repeated 10 times, followed by washing with acetone and drying. 6 at 450 ° C in a stream of dry nitrogen
The mixture was heated for a period of time to remove adsorbed water.

7 g of this alumina was suspended in 50 ml of n-hexane, and 82 mg of methylaminooxane dissolved in 10 ml of toluene.
(1.4 mmol aluminum units) was added. This mixture was stirred at room temperature for 30 minutes, 9 ml of a 0.16 M solution of tetrabenzylzirconium dissolved in toluene was added, and the mixture was further 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 amounts of Zr and Al, and it was found that 0.2 mmol / g of zirconium and 0.2 mm
It contained ol / g of aluminum.

Propylene Polymerization 100 stainless steel autoclaves equipped with a stirrer were vacuum degassed and replaced with nitrogen, and then the hydrogen partial pressure at 25 ° C was reduced to 0.
Hydrogen and ethylene were charged so that the pressure was 6 kg / cm ² and the ethylene partial pressure was 3 kg / cm ^2, and then 25 kg of propylene was charged. After heating the system and adding the catalyst slurry prepared by the above method into the autoclave by a pressure equalizer at 50 ° C, ethylene was continuously supplied, and the temperature was 60 ° C and the total pressure was 29 kg / cm ² . The copolymerization was carried out for 2 hours while maintaining. After the polymerization was stopped by adding 50 ml of isopropyl alcohol, unreacted propylene was removed and the produced polymer was taken out. White,
11.8 kg of a copolymer having a spherical particle size was obtained, the ethylene content of the polymer was 42% by weight, the MFI was 1.01 g / 10 minutes, and the bulk specific gravity was
It was 0.25 g / cm ³ . Various physical properties of the obtained copolymer are shown in Table 2.

Examples 2 to 7 Catalysts were prepared and copolymerized in the same manner as in Example 1 except that the types of catalyst and α-olefin and the polymerization conditions were changed as shown in Table 1. The polymerization results are shown in Table 1, and the physical properties of the resulting copolymer are shown in Table 2.

Example 8 In the same manner as in Example 1, an autoclave deaerated and replaced with nitrogen was charged with 25 kg of propylene, a partial pressure of ethylene of 7 kg / cm ² , and a partial pressure of hydrogen of 1.0 kg / cm ² . The system was heated and the catalyst slurry prepared in the same manner as in Example 1 was added by a pressure equalizer at 35 ° C., and then prepolymerized at 40 ° C. for 5 minutes. Then, the temperature was raised to 60 ° C., ethylene was continuously supplied, and copolymerization was carried out for 1.7 hours while maintaining a total pressure of 29 kg / cm ² . Post-treatment was carried out in the same manner as in Example 1 to obtain a white, spherical copolymer 1 having a uniform particle size.
I got 1.2 kg. Table 2 shows the physical properties of the product.

Comparative Example 1 Catalyst preparation and copolymerization were carried out in the same manner as in Example 1 except that tetra neophyll zirconium was used as the organic transition metal compound and no organoaluminum compound was used.
The polymerization was stopped 1.3 hours after the start of the polymerization because the stirring became unsuccessful. Since the produced polymer was in a blocked state, the bulk specific gravity could not be measured. The breaking strength of the polymer is 30 kg
As small as / cm ² , tackiness was observed on the surface of the test piece. Other physical property values are shown in Table 2.

Comparative Example 2 Catalyst preparation and copolymerization were carried out according to Example 1. The polymerization conditions are as shown in Table 1. After 1.5 hours from the start of the polymerization, the stirring became unsuccessful, so the polymerization was stopped. The product was in a blocked state, and the bulk specific gravity could not be measured. The product had an ethylene content of 17% by weight and had poor low temperature properties. Other physical property values are shown in Table 2.

Comparative Example 3 A catalyst was prepared according to Example 1 to homopolymerize propylene. The polymerization conditions are as shown in Table 1. Comparative example
As in 1 and 2, the polymerization was stopped because the stirring became unsuccessful. The product was in a blocked state, and the bulk specific gravity could not be measured. The product had a high breaking strength of 135 kg / cm ² , but had a small impact resilience of 24% and poor low temperature properties, and was not suitable for use as a thermoplastic elastomer.

Comparative Example 4 The procedure of Example 1 was repeated except that the amount of hydrogen added was 1.5 kg / cm ² and the total pressure was maintained at 30 kg / cm ² . Since the stirring became unsuccessful 1.3 hours after the start of the polymerization, the polymerization was stopped. The polymer produced is block-shaped, and its physical properties are as follows: MFI is large at 12.4 g / 10 minutes, breaking strength is small at 40 kg / cm ^2, and permanent elongation is 32%.
It was great.

Comparative Example 5 The procedure of Example 1 was repeated, except that the catalyst addition temperature was 25 ° C., the polymerization temperature was 30 ° C., and the total pressure was maintained at 15 kg / cm ² . The polymerization activity was low, the shape of the polymer was a little poor, and the bulk specific gravity was small at 0.10 g / cm ³ .

Comparative Example 6 According to the polymerization method of Example 1, copolymerization was performed under the polymerization conditions shown in Table 1. Good granular ethylene content 89% by weight
Although a high ethylene copolymer was obtained, it had a hardness as high as 100 and a permanent elongation of 67%, which was beyond the range of thermoplastic elastomers.

Comparative Example 7 A catalyst was prepared and copolymerized in the same manner as in Example 1 except that 30 kg of hexane was used as the inert hydrocarbon. When the polymerization time reached 1.5 hours, the stirring became unsuccessful, so the polymerization was stopped. The product was in a blocked state, and the bulk specific gravity could not be measured. The polymerization results are shown below.

Yield: 7.0 kg Polymerization activity: 3.3 kg / mmol ・ hr Ethylene content: 45 wt% MFI: 1.20 g / 10 min Particle shape: Poor hardness: 60 Torsional rigidity: 27 kg / cm ² Breaking strength: 80 kg / cm ² Elongation at break: 840% Rebound modulus: 62% Permanent elongation: 19% Low temperature embrittlement temperature: <-70 ° C

[Brief description of drawings]

 FIG. 1 is a diagram showing a process for preparing a catalyst according to the present invention.

Claims (6)

[Claims] 1. A hot-water-treated and heat-treated porous fine-particle form of γ-alumina is added to the general formula R _p ¹ MX _q (wherein M is
Is Zr or Ti, R ¹ represents a benzyl group, X is halogen, p and q are integers, p is the maximum valence of 2 to M, and q is 2 from the valence of 0 to M. In the presence of a transition metal catalyst obtained by catalytically reacting an organic transition metal compound represented by a small value), ethylene and the α-olefin are used as a comonomer having an α-olefin having 3 to 12 carbon atoms as a polymerization solvent. A method for producing a thermoplastic elastomer, which comprises subjecting an olefin to slurry polymerization to contain 25 to 85% by weight of copolymerized ethylene in a produced polymer. 2. The method according to claim 1, wherein the γ-alumina is a particle having a regular shape such as a sphere or an ellipsoid having a particle diameter of 20 to 200 μm. 3. The method according to claim 1, wherein the ethylene partial pressure is 0.5 to 20 kg / cm ² . 4. The method according to claim 1, wherein the hydrogenation pressure is 0.1 to 10 kg / cm ² . 5. The method according to claim 1, wherein the α-olefin is propylene. 6. The method according to claim 1, wherein the slurry polymerization is carried out at a temperature of 45 to 80 ° C.