JP2000186174A - Olefin-based thermoplastic elastomer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain an olefin-based thermoplastic elastomer excellent in both balances of flexibility with a tensile breaking point and the flexibility with a low temperature impact resistance. SOLUTION: This olefin-based thermoplastic elastomer consists of the following components (A) and (B), and is obtained by dynamically heat-treating a composition obtained by polymerizing the component (B) after polymerizing the component (A), in the presence of a cross-linking agent and a cross-linking assistant. (A) Propylene homopolymer having >=85% isotactic index or a copolymer of propylene with another 2-8C α-olefin: 10-60 wt.% based on the total amount of the composition. (B) A copolymer of propylene with another 2-8C α-olefin, containing propylene and ethylene as indispensable components and its composition satisfies the following conditions: 40-90 wt.% based on the total amount of the composition. Insoluble fraction of the copolymer to xylene at a room temperature; >=5 wt.% and <10 wt.% based on the total amount of the composition. Soluble fraction of the copolymer to xylene at a room temperature; >=30 wt.% and <=85 wt.% based on the total amount of the composition. Ethylene content in the xylene soluble fraction; >=40 wt.%.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an olefin-based thermoplastic elastomer having an excellent balance between flexibility, elongation at break, and low-temperature impact resistance.

[0002]

2. Description of the Related Art In recent years, a styrene-based, olefin-based, polyester-based, soft rubber-like material that does not require a vulcanizing step and has the same moldability as a thermoplastic resin.
Polyamide-based and polyurethane-based thermoplastic elastomers are attracting attention from the viewpoints of streamlining processing processes and recycling of used materials, and are widely used in the fields of automobile parts, home appliance parts, medical equipment parts, electric wires, and miscellaneous goods. It is used. Among them, a mixture of a crystalline propylene resin and an olefin rubber such as an ethylene-propylene copolymer rubber or an ethylene-propylene-non-conjugated diene copolymer rubber, or dynamically heat-treating the mixture in the presence of an organic peroxide. Olefin-based thermoplastic elastomers obtained by crosslinking the latter rubber component to obtain partially crosslinked products have attracted attention as economically advantageous materials because they are relatively inexpensive.

[0003] However, since this olefin-based thermoplastic elastomer is a mixture, the rubber component is likely to be coarsely dispersed or non-uniformly dispersed, and therefore has a higher flexibility and tensile strength than other thermoplastic elastomers and vulcanized rubber. Elongation at break, and poor balance between flexibility and low temperature impact resistance,
For example, the same degree of flexibility has a problem that elongation at break at break and low-temperature impact resistance are poor.

In order to solve such a problem, a composition obtained by producing a composition of a crystalline propylene resin and a copolymer rubber containing ethylene-propylene as a main component by polymerization and then dynamically crosslinking the composition. For example, Japanese Patent Nos. 26199942 and 2807512 disclose a method of dynamically cross-linking polymer particles composed of a crystalline olefin polymer and an amorphous olefin polymer to obtain a tensile strength. A method for producing a thermoplastic elastomer having excellent strength, flexibility, low-temperature impact resistance and the like has been proposed.

[0005] Also, Japanese Patent Application Laid-Open No.
5 to 50% by weight of a crystalline propylene polymer, 0 to 20% by weight of a room temperature xylene insoluble copolymer fraction containing ethylene, propylene and / or an α-olefin having 4 to 10 carbon atoms, and 35% by weight or less of ethylene Dynamically crosslinks a composition produced by polymerization comprising 40 to 95% by weight of a room temperature xylene-soluble copolymer fraction containing ethylene, propylene and / or an α-olefin having 4 to 10 carbon atoms. It is stated that the method and the resulting composition have excellent tensile elongation at break.

However, according to the study of the present inventors, after a composition of a crystalline propylene polymer and a copolymer rubber containing ethylene-propylene as a main component is produced by polymerization, the composition is dynamically crosslinked. Although the composition obtained by the method may have excellent tensile elongation at break,
It was found that the low-temperature impact resistance (Izod impact strength of −40 ° C. or less) was inferior, and the balance between the flexibility and the elongation at break, and the flexibility and the low-temperature impact resistance were still insufficient.

[0007]

DISCLOSURE OF THE INVENTION The present invention has been made in view of the above-mentioned prior art, and has excellent balance between flexibility and tensile elongation at break, and flexibility and low-temperature impact resistance. It is intended to provide an olefin-based thermoplastic elastomer.

[0008]

The gist of the present invention consists of the following components (A) and (B), and is obtained by polymerizing component (B) after polymerization of component (A). An olefin-based thermoplastic elastomer obtained by dynamically heat-treating the composition in the presence of a crosslinking agent and a crosslinking aid. (A) an isotactic index of 85% or more,
Propylene homopolymer or copolymer of propylene and another α-olefin having 2 to 8 carbon atoms: 10 to 60% by weight based on the whole composition (B) Propylene and ethylene are essential components , A copolymer of propylene and another α-olefin having 2 to 8 carbon atoms, the composition of which satisfies the following conditions: 40 to 90% by weight of the whole composition Room temperature xylene insolubles; 5 based on total composition
At least 10% by weight of the copolymer at room temperature and soluble in xylene;
0 to 85% by weight Ethylene content in the above xylene solubles at room temperature; 40% by weight or more

Another gist of the present invention is that the above-mentioned olefinic thermoplastic elastomer wherein the component (A) is a propylene homopolymer, and the above-mentioned olefin wherein the component (B) is a copolymer of propylene and ethylene. And the olefin-based thermoplastic elastomer having an ethylene content of 40 to 60% by weight in the xylene-soluble component at room temperature of the component (B). One gist is that the olefinic thermoplastic elastomer in which the crosslinking agent is an organic peroxide, the olefinic thermoplastic elastomer in which the amount of the crosslinking agent is 0.05 to 5 parts by weight per 100 parts by weight of the composition, The amount of the olefin-based thermoplastic elastomer using divinylbenzene as a crosslinking aid and the amount of the crosslinking aid used in the composition 100
The olefinic thermoplastic elastomer is present in an amount of 0.05 to 5 parts by weight per part by weight.

[0010] Another aspect of the present invention is that a thermoplastic elastomer can be used at a temperature of 100 to 350 ° C for a processing time of 0.2 to
The above-mentioned olefin-based thermoplastic elastomer obtained by performing dynamic heat treatment by kneading using a kneading apparatus in a molten state under the conditions of 30 minutes, and the olefin wherein the kneading apparatus is a twin-screw extruder Also present in thermoplastic elastomers.

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION One of the components constituting the olefin-based thermoplastic elastomer composition of the present invention, (A)
The component is composed of a propylene homopolymer having an isotactic index of 85% or more, or a copolymer of propylene and another α-olefin having 2 to 8 carbon atoms. Is preferred, and
The isotactic index is preferably 90% or more. Note that, in the present invention, the isotactic index is defined as “2” using n-heptane in a sample polymer.
The residue obtained by Soxhlet extraction for 4 hours is indicated by weight%. This component (A) usually comprises a crystalline component insoluble in room temperature xylene and an amorphous component soluble in room temperature xylene, and the former insoluble component substantially corresponds to the isotactic index. If the component (A) has an isotactic index of less than 85%, the balance between the flexibility of the composition as a thermoplastic elastomer and the elongation at break is inferior.

When the component (A) is a copolymer, examples of the "other α-olefin having 2 to 8 carbon atoms" include ethylene, butene-1, 3-methylbutene-1, and pentene. -1,4-methylpentene-1, hexene-1, octene-1, and the like. Particularly preferred is ethylene, and the propylene content in this copolymer is 8%.
It is preferably at least 5% by weight.

The other component (B) constituting the olefin-based thermoplastic elastomer composition of the present invention comprises:
It is a copolymer of propylene and another α-olefin having 2 to 8 carbon atoms containing propylene and ethylene as essential components, and among them, a copolymer of propylene and ethylene is preferable. Other α having 2 to 8 carbon atoms used herein
Examples of the olefin include those similar to the component (A).

The component (B) further includes 1,4-hexadiene, 5-methyl-1,5-hexadiene, 1,4
-Octadiene, cyclohexadiene, cyclooctadiene, dicyclopentadiene, 5-ethylidene-2-norbornene, 5-butylidene-2-norbornene, 2-
A non-conjugated diene such as isopropenyl-5-norbornene may be copolymerized in the component (B) at a ratio of 0.5 to 10% by weight.

In the present invention, the copolymer of component (B) comprises a crystalline component insoluble in xylene at room temperature and an amorphous component soluble in xylene at room temperature. 5% by weight or more and 10% by weight
Less than 30 room temperature xylene solubles relative to the total composition.
It is necessary to satisfy the condition that the ethylene content in the xylene-soluble component at room temperature is 40% by weight or more. Particularly preferred room temperature xylene-soluble content is 40% by weight or more and 65% by weight or less based on the whole composition, and the ethylene content in the room temperature xylene-soluble content is preferably 40-60% by weight.

When the component (B) has a room temperature xylene-insoluble content of less than 5% by weight based on the composition or a room temperature xylene-soluble component exceeds 85% by weight based on the composition, the moldability of the composition is high. On the other hand, when the xylene-insoluble content at room temperature is 10% by weight or more with respect to the composition or the xylene-soluble content at room temperature is less than 30% by weight with respect to the composition, the flexibility and elongation at break at tensile strength are poor. The balance tends to be poor. Further, the ethylene content in the xylene solubles at room temperature was 4%.
If it is less than 0% by weight, the balance between the flexibility of the composition and the low-temperature impact resistance tends to be poor. If the ethylene content in the xylene solubles at room temperature is too high, the balance between flexibility and tensile elongation at break tends to be poor. The more preferable ethylene content in the xylene-soluble component at room temperature is 40 to 60% by weight as described above.

In the composition for an olefinic thermoplastic elastomer of the present invention, the component (A) is 10 to 60% by weight and the component (B) is 40 to 90% by weight. More preferably, component (A) is 30 to 50% by weight and component (B) is 50 to 70% by weight. Less than 10% by weight of component (A) or 9% of component (B)
If the amount exceeds 0% by weight, the molding processability of the composition is poor,
On the other hand, when the amount of the component (A) exceeds 60% by weight or the amount of the component (B) is less than 40% by weight, the balance between the moldability and the impact resistance is deteriorated.

The composition for an olefinic thermoplastic elastomer of the present invention is obtained by polymerizing the component (B) after the polymerization of the component (A), and is used for this sequential polymerization. As the catalyst, a catalyst comprising an organoaluminum compound and a solid component containing titanium, magnesium, halogen, and an electron donating compound is preferably used.

Here, as the organoaluminum compound, a compound represented by the general formula R ¹ _m AlX _3-m (where R ¹ is a hydrocarbon group having 1 to 12 carbon atoms, X is a halogen, and m is 1 to 3)
3, a trialkylaluminum such as trimethylaluminum and triethylaluminum, a dialkylaluminum halide such as dimethylaluminum chloride and diethylaluminum chloride, an alkyl such as methylaluminum sesquichloride and ethylaluminum sesquichloride. Alkyl aluminum dichloride such as aluminum sesquihalide, methyl aluminum dichloride, ethyl aluminum dichloride and the like can be mentioned.

The solid component containing titanium, magnesium, halogen and an electron-donating compound, which is a titanium compound serving as a titanium source, has a general formula of Ti (O
R ² ) _{4- n} X _n (wherein, R ² is a hydrocarbon group having 1 to 10 carbon atoms, X is a halogen, and n is a number of 0 to 4). Especially titanium tetrachloride,
Tetraethoxytitanium, tetrabutoxytitanium and the like are preferred. Similarly, examples of the magnesium compound serving as a source of magnesium include dialkylmagnesium, magnesium dihalide, dialkoxymagnesium, and alkoxymagnesium halide, and magnesium dihalide is preferable. As halogen, fluorine,
Chlorine, bromine and iodine can be mentioned, and among them, chlorine is preferable.
The halogen is usually supplied from the above-mentioned titanium compound or magnesium compound, but may be supplied from another halogen-containing compound such as an aluminum halide, a silicon halide, and a tungsten halide.

An electron donating compound contained in the solid component
Alcohols, phenols, ketones, alcohols
Aldehydes, carboxylic acids, organic or inorganic acids and their
Oxygenated compounds such as derivatives, ammonia, amines, nitrite
Examples include nitrogen-containing compounds such as rils and isocyanates.
Among them, inorganic acid esters, organic acid esters, and organic acid
And the like are preferred, and silicate esters and phthalate esters
, Cellosolve acetate, phthalic halide, etc.
Preferred. Particularly preferred is the general formula R^ThreeR ^Four _3-pS
i (OR^Five)_p(Where R^ThreeIs 3-20 carbon atoms, preferably
Preferably 4 to 10 branched aliphatic hydrocarbon groups or carbon
C5-20, preferably C6-10 cycloaliphatic carbonized
Represents a hydrogen group;^FourIs 1-20 carbon atoms, preferably
Represents 1 to 10 branched or linear aliphatic hydrocarbon groups,
^FiveIs an aliphatic carbon having 1 to 10, preferably 1 to 4 carbon atoms
Represents a hydride group, and p is a number of 1 to 3)
Organosilicon compounds, such organosilicon compounds
For example, t-butyl-methyl-dimethoxysila
, T-butyl-methyl-diethoxysilane, cyclohexane
Xyl-methyl-dimethoxysilane, cyclohexyl-
Methyl-diethoxysilane and the like can be mentioned.

In the production of the composition as a raw material of the olefin-based thermoplastic elastomer of the present invention, in the first step, propylene or propylene and another α-olefin having 2 to 8 carbon atoms are supplied, and In the presence of such a catalyst, the temperature is 50 to 150 ° C, preferably 50 to 100 ° C, and the partial pressure of propylene is 0.5 to 4.5 MPa, preferably 1.0 to
Under the conditions of 3.5 MPa, propylene homopolymerization or copolymerization of propylene and α-olefin is carried out to produce the component (A), and then, in the second step, propylene and ethylene or propylene and ethylene And an α-olefin having 4 to 8 carbon atoms is supplied at a temperature of 5 in the presence of the catalyst.
Under conditions of 0 to 150 ° C, preferably 50 to 100 ° C, and partial pressures of propylene and ethylene of 0.3 to 4.5 MPa, preferably 0.5 to 3.5 MPa, respectively, propylene-ethylene copolymerization or propylene -By performing terpolymerization of ethylene-α-olefin to produce the component (B).

The polymerization system may be any of a batch system, a continuous system, and a semi-batch system. The first stage polymerization is preferably carried out in a gas phase or a liquid phase, particularly in a gas phase. Also, the second stage polymerization is preferably carried out in the gas phase. The residence time of each stage is usually 0.5 to 10 hours each,
More preferably, it is set to 5 hours. In order to improve the fluidity by eliminating stickiness and the like of the powder particles produced by the above method, after the polymerization of the component (A) in the first stage, before or during the polymerization of the component (B) in the second stage. First, the active hydrogen-containing compound is added to the solid component of the catalyst in an amount of 100
It is preferable to add the compound in an amount of up to 1000 times mol and 2 to 5 times mol of the organic aluminum compound. Examples of the active hydrogen-containing compound that can be used here include water, alcohols, phenols, aldehydes, carboxylic acids, acid amides, ammonia, amines, and the like.

The olefin-based thermoplastic elastomer of the present invention is obtained by dynamically heat-treating the composition comprising the above-mentioned components (A) and (B) in the presence of a crosslinking agent and a crosslinking aid to cause crosslinking. It is. The operation of `` dynamically heat-treating '' refers to kneading the composition in a molten state using a kneading device such as a mixing roll, a kneader, a Banbury mixer, a Brabender plastograph, a single-screw or twin-screw extruder. The condition is that the temperature is 100 to 350
° C, preferably at 120-280 ° C, for a time of 0.2-3
It is generally 0 minutes, preferably 0.5 to 20 minutes.

In the present invention, it is preferable to use a twin screw extruder as the kneading device. The twin screw extruder has a ratio (L) of the screw length (L) to the screw diameter (D).
/ D), the kneading characteristics differ depending on the biaxial rotation direction, the biaxial meshing mode (for example, separation type, contact type, partial meshing type, full meshing type, etc.).
/ D is preferably 10 to 100, the rotation direction is the same, and the meshing form is a partial or complete meshing type.

As the method of supplying the composition, the crosslinking agent and the crosslinking aid to the kneading apparatus during the dynamic heat treatment, a method of supplying these at once, a method of adding a crosslinking agent and a crosslinking aid to the composition melt-kneaded in advance. And a method of adding a composition (so-called masterbatch) in which a composition, a cross-linking agent and a cross-linking auxiliary have been melt-kneaded in advance to a composition which has been melt-kneaded in advance.

As the crosslinking agent used in the dynamic heat treatment for obtaining the olefin thermoplastic elastomer of the present invention, organic peroxides, phenolic crosslinking agents, sulfur, oxime compounds, polyamine compounds and the like can be used. Among them, organic peroxides and phenolic crosslinking agents are preferred, and organic peroxides are particularly preferred. Specific examples of the organic peroxide include, for example, di-t-butyl peroxide and t-butyl peroxide.
-Butyl cumyl peroxide, dicumyl peroxide,
Dialkyl peroxides such as 2,5-dimethyl-2,5-di (t-butylperoxy) hexane and 2,5-dimethyl-2,5-di (t-butylperoxy) hexyne-3; Butyl peroxybenzoate, 2,5-
Peroxyesters such as dimethyl-2,5-di (benzoylperoxy) hexane, 2,5-dimethyl-2,5-di (benzoylperoxy) hexyne-3, diacyl peroxides such as benzoyl peroxide; Hydroperoxides such as diisopropylbenzene hydroperoxide and the like are preferable. Among them, dialkyl peroxides are preferable, and in particular, 2,5-dimethyl-2,5-di (t
-Butylperoxy) hexane is preferred.

As the crosslinking aid, a compound having two or more polymerizable functional groups is used, for example, divinylbenzene, metaphenylenebismaleimide, quinonedioxime, 1,2-butadiene, triallyl cyanurate,
Triallyl isocyanurate, diallyl phthalate, ethylene glycol dimethacrylate, triethylene glycol dimethacrylate, trimethylolpropane trimethacrylate, and the like can be mentioned. Among them, divinylbenzene and trimethylolpropane trimethacrylate are preferable.

Further, in the present invention, an anti-scorch agent can be used to homogenize the crosslinking reaction and prevent scorch. Examples of such a scorch inhibitor include mercaptobenzothiazole, hydroquinones, phenylamines, α-methylstyrene dimer, and the like. The amount of each of these crosslinking agents and crosslinking aids is 0.05 to 100 parts by weight of the composition.
It is preferably about 5 parts by weight, particularly preferably about 0.2 to 3 parts by weight.

The olefinic thermoplastic elastomer of the present invention is obtained by dynamically heat-treating the composition comprising the components (A) and (B) in the presence of a crosslinking agent and a crosslinking aid as described above. A partially or completely crosslinked composition obtained by performing a reaction. The general characteristics of the olefin-based thermoplastic elastomer of the present invention are as follows. (1) Melt flow rate: 1 to 5 g / 10 minutes (JIS
230 ° C, load 21.18 according to K7210
N) (2) Density: 0.87 to 0.89 g / cm ³ (JIS
(Measured by an underwater displacement method in accordance with K7112) (3) Flexural modulus: 600 MPa or less, for example, 100 to 100 MPa
500MPa (23 ° C according to JIS K7203)
(4) Tensile elongation at break: 600% or more (JIS K71)
(Measured at a temperature of 23 ° C. in accordance with No. 13) (5) Izod impact test: No break at −40 ° C. (JI
SK7110) Incidentally, the olefin-based thermoplastic elastomer of the present invention may contain a rubber softener which is usually compounded to impart processability, flexibility and the like to the thermoplastic elastomer.

As the rubber softener, mineral oil is particularly preferred. Mineral oil is generally a mixture of an aromatic ring-containing hydrocarbon, a naphthenic ring-containing hydrocarbon and a paraffin chain-containing hydrocarbon, wherein the number of carbon atoms in the paraffin chain-containing hydrocarbon is 50% of the total number of carbon atoms. % Or more of the paraffinic mineral oil, the naphthenic mineral oil in which the number of carbon atoms in the naphthenic ring-containing hydrocarbon accounts for 30 to 40% of the total carbon atoms, and the number of carbon atoms in the aromatic ring-containing hydrocarbon are Although it is classified into an aromatic mineral oil occupying 30% or more of the total number of carbon atoms, in the present invention, a paraffinic mineral oil is particularly preferred.

The olefin-based thermoplastic elastomer of the present invention contains, in addition to the above components, various resins and rubbers, glass fibers, fillers such as calcium carbonate, silica, talc, mica, clay, antioxidants, light-stable Various additives such as an agent, an antistatic agent, a lubricant, a dispersant, a neutralizing agent, a flame retardant, a pigment such as carbon black, and the like may be blended as long as the objects and effects of the present invention are not impaired. The olefin-based thermoplastic elastomer of the present invention has a desired shape as a simple substance or a laminate with other materials by various molding methods such as extrusion molding, injection molding, and compression molding usually applied to thermoplastic elastomers. Into a molded body.

[0033]

EXAMPLES Hereinafter, the present invention will be described more specifically with reference to examples, but the present invention is not limited to the following examples unless it exceeds the gist.

<Examples 1 to 4, Comparative Examples 1 to 3> Production of solid catalyst 20 liters of dehydrated and deoxygenated n-heptane was introduced into a reactor equipped with a stirrer having an internal volume of 50 liters and purged with nitrogen.
Next, 4 mol of magnesium chloride and 8 mol of tetrabutoxytitanium were introduced and reacted at 95 ° C. for 2 hours. Then, the temperature was lowered to 40 ° C., and 480 ml of methylhydropolysiloxane (viscosity: 20 centistokes) was introduced. After further reacting for 3 hours, the reaction solution was taken out, and the generated solid component was washed with n-heptane.

Subsequently, 15 liters of dehydrated and deoxygenated n-heptane were introduced into another reactor equipped with a stirrer, and 3 mol of the obtained solid component was introduced in terms of magnesium atom. A mixture obtained by adding 8 mol to 25 ml of n-heptane was introduced at 30 ° C. over 30 minutes, then the temperature was raised to 90 ° C., and the mixture was reacted for 1 hour, and the generated solid component was washed with n-heptane.

5 liters of dehydrated and deoxygenated n-heptane were introduced into the same reactor equipped with a stirrer, and 250 g of the titanium-containing solid component obtained above and 1,5-hexadiene 75
After introducing 0 g, 130 ml of t-butyl-methyl-dimethoxysilane, 10 ml of divinyldimethylsilane, and 225 g of triethylaluminum and contacting each other at 30 ° C. for 2 hours, the resulting solid was converted into n-
Washing with heptane gave a solid catalyst. The obtained solid catalyst had a prepolymerization amount of 1,5-hexadiene of 2.97 g per titanium-containing solid component.

2. Production of Olefinic Thermoplastic Elastomer Composition (First Stage Polymerization) In a first stage reactor having an internal volume of 550 liters, a temperature of 70 ° C. and a pressure of about 3.2 MPa were used.
Propylene, triethylaluminum, and the solid catalyst obtained in the above 1 in such an amount that the polymer formation rate becomes 30 kg / hour are continuously supplied, and hydrogen is continuously supplied as a molecular weight controlling agent. The polymerization was carried out in the liquid phase.

(Second Stage Polymerization) Subsequently, the produced polymer was introduced into a second stage reactor having an internal volume of 1900 liters via a propylene purge tank. Here, at a temperature of 60 ° C,
At a pressure of 3.0 MPa, propylene and ethylene are continuously supplied, hydrogen is continuously supplied as a molecular weight controlling agent, and ethanol is supplied to the solid component catalyst supplied in the first stage. It was supplied in a molar amount of 200 times with respect to titanium atoms and 2.5 times with respect to triethylaluminum. The composition ratio in the produced copolymer was adjusted by the supply ratio of propylene and ethylene and the supply amount of hydrogen. The polymerization was carried out in the gas phase, and after the resulting polymer was continuously transferred to the receiver, the reaction was stopped by introducing nitrogen gas containing water.

3. Evaluation of Composition For each composition produced as described above, the weight ratio of component (A) to the entire composition, the weight ratio of room temperature xylene-insoluble and soluble components to the entire composition in component (A), And the isotactic index of component (A),
And a weight ratio of the component (B) to the whole composition,
(B) the weight ratio of the room temperature xylene insoluble matter and the soluble matter to the whole composition in the component, and the content of α-olefin (ethylene) other than propylene in the room temperature xylene soluble matter,
Was measured by the following methods. Table 1 shows the results.

(1) The weight ratio of the component (A) and the component (B) to the whole composition and the weight ratio of the component (B) to the whole composition (referred to as B (%)) were obtained. It was calculated from the weight of the composition and the weight of propylene and ethylene supplied in the second stage polymerization. From this, the weight ratio of the component (A) to the whole composition (this is referred to as A (%)) is defined as “100-B”.
Was calculated by (2) Room temperature xylene-insoluble and soluble components in each component: weight ratio based on the total composition 1 g of the polymer obtained after the first-stage polymerization was stirred at 140 ° C. (boiling point of xylene) in 300 ml of xylene. After lowering the temperature to 100 ° C. within one hour while continuing stirring, the solution was stirred for 2 hours while continuing to stir.
The mixture was rapidly cooled to 3 ± 2 ° C. and left for 20 minutes or more. The precipitate due to quenching was naturally filtered with filter paper, and the filtrate was evaporated to dryness using an evaporator, dried at 120 ° C. for 2 hours under reduced pressure, allowed to cool, and weighed. From this, the weight ratio of the xylene-soluble component at room temperature in the component (A) (this is referred to as a2 (%)) was determined. Similarly, the weight ratio of the xylene-soluble component at room temperature in the whole polymer composition produced (this is defined as C (%))
Was measured.

The weight ratio of the xylene soluble component at room temperature in the component (A) to the whole composition (this is defined as A2 (%)).
Is calculated from “A2 × A / 100” and the weight ratio of the insoluble portion of room temperature xylene in the component (A) to the whole composition (this is referred to as A1 (%)) is calculated from “A-A2”. Similarly, the weight ratio of the room temperature xylene-soluble component (B2 (%)) in the component (B) is determined by “C-A2”, and the composition of the room temperature xylene-insoluble component in the component (B). Weight ratio to the whole (this is B1 (%))
Was calculated by “B-B2”.

(3) Isotactic Index of Component (A) The polymer produced after the first-stage polymerization was subjected to Soxhlet extraction with n-heptane and measured as a residual amount (% by weight). (4) Ethylene content in room-temperature xylene-soluble component of component (B) Ethylene content in room-temperature xylene-soluble component of the polymer obtained after the first-stage polymerization (this is referred to as EA2 (%)); as well as,
The content of ethylene in the xylene-soluble component at room temperature of the resulting polymer composition (hereinafter referred to as EC (%)) was measured by infrared spectroscopy, and calculated by the following equation.

[EC-EA2 × (A2 / C)] / [B2 / C]

(5) Melt flow rate According to JIS K7210, temperature 230 ° C., load 2
It was measured at 1.18N. 4. Dynamic heat treatment of the composition and evaluation of the obtained olefin-based thermoplastic elastomer The composition obtained above was added with tetrakis [methylene-3- (3 ′, 5′-di-t-butyl-4) as an antioxidant. '
-Hydroxyphenyl) propionate] methane (IRGANOX 1010 (trade name) manufactured by Ciba-Geigy Japan) and tris (2,4-di-t-butylphenyl) phosphite (IRGAFOS 168 (trade name) manufactured by Ciba-Geigy Japan) As a neutralizing agent, zinc stearate was added in an amount of 0.05 part by weight based on 100 parts by weight of the elastomer composition, and 2,5-dimethyl-2,5-di (t-
0.2 parts by weight of butylperoxy) hexane and 0.3 parts by weight of divinylbenzene as a crosslinking aid were added. In Example 3, 10 parts by weight of paraffinic mineral oil was added in addition to these.

The composition was set at a set temperature of 20 using a twin-screw extruder (PCM45, manufactured by Ikegai) having a cylinder diameter of 45 mm.
The mixture was melt-kneaded at 0 ° C and pelletized to obtain an olefin-based thermoplastic elastomer. An injection molding machine (Model N-100 manufactured by Nippon Steel Works) with a mold clamping pressure of 100 t is used for this elastomer.
175 ° C under the hopper, cylinder temperature 2
A test piece was injection molded at 20 ° C., a nozzle temperature of 210 ° C., and a mold temperature of 40 ° C., and the hardness, flexural modulus, tensile properties, impact strength, and the like were measured by the following methods. Table 1 shows the results
Shown in

(1) Hardness A durometer hardness of type D was measured according to JIS K7215. (2) Flexural modulus Measured at a temperature of 23 ° C. in accordance with JIS K7203. (3) Tensile properties According to JIS K7113, using a No. 2 type test piece,
At a temperature of 23 ° C. and a tensile speed of 50 mm / min, the tensile yield point strength, tensile break strength, and tensile break elongation were measured. (4) Impact strength According to JIS K7110, temperature -30 ° C and -40
At, the notched Izod impact strength was measured. (5) Melt flow rate It measured similarly to (5). (6) Density Measured by the underwater displacement method according to JIS K7112.

5. Evaluation of Results As can be seen from Table 1, it is clear that the thermoplastic elastomer of the present invention has the following properties. (1) Comparative Example 1 in which the room temperature xylene-insoluble component and the room temperature xylene-soluble component of the component B are out of the range of the present invention has a tensile property, particularly a tensile elongation at break, as compared with Examples 2 and 3 having similar hardness. Inferior. (2) Comparative Example 2, in which the ethylene content in the xylene-soluble component at room temperature of the component B is less than the range of the present invention, is inferior in impact strength at low temperatures. (3) Comparative Example 3 in which the ethylene content in the room temperature xylene insoluble component of the component B and the room temperature xylene soluble component of the component B is out of the range of the present invention is inferior in impact resistance at low temperatures.

[0048]

[Table 1]

[0049]

[Table 2]

[0050]

The olefinic thermoplastic elastomer of the present invention has an excellent balance between flexibility, elongation at break and tensile strength at low temperatures.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI theme coat ゛ (Reference) C08L 23/14 C08L 23/14 F term (Reference) 4F070 AA15 AA16 AC56 AE08 BA02 GB02 GB09 GC07 4J002 BB12X BB14W BB14X BB15W BB15X FD010 FD090 FD200 GF00 4J026 HA02 HA04 HA27 HB03 HB04 HB47 HB49 HB50 HE01

Claims (9)

[Claims] 1. A composition comprising the following components (A) and (B), and obtained by polymerizing the component (B) after the polymerization of the component (A), comprises a crosslinking agent and a crosslinking assistant. An olefinic thermoplastic elastomer dynamically treated in the presence of olefin. (A) an isotactic index of 85% or more,
Propylene homopolymer or copolymer of propylene and another α-olefin having 2 to 8 carbon atoms: 10 to 60% by weight based on the whole composition (B) Propylene and ethylene are essential components , A copolymer of propylene and another α-olefin having 2 to 8 carbon atoms, the composition of which satisfies the following conditions: 40 to 90% by weight of the whole composition Room temperature xylene insolubles; 5 based on total composition
At least 10% by weight of the copolymer at room temperature and soluble in xylene;
0 to 85% by weight Ethylene content in the above xylene solubles at room temperature; 40% by weight or more 2. The olefin-based thermoplastic elastomer according to claim 1, wherein the component (A) is a propylene homopolymer. 3. The thermoplastic olefin elastomer according to claim 1, wherein the component (B) is a copolymer of propylene and ethylene. 4. The olefin thermoplastic elastomer according to claim 1, wherein the ethylene content of the component (B) in the xylene-soluble component at room temperature is 40 to 60% by weight. 5. The method according to claim 1, wherein the crosslinking agent is an organic peroxide.
5. The olefin-based thermoplastic elastomer according to any one of 4. 6. The olefinic thermoplastic elastomer according to claim 1, wherein the amount of the crosslinking agent used is 0.05 to 5 parts by weight per 100 parts by weight of the composition. 7. The olefinic thermoplastic elastomer according to claim 1, wherein the amount of the crosslinking aid is 0.05 to 5 parts by weight per 100 parts by weight of the composition. 8. A thermoplastic elastomer obtained by performing dynamic heat treatment by kneading a composition in a molten state using a kneading apparatus at a temperature of 100 to 350 ° C. for a processing time of 0.2 to 30 minutes. The olefin-based thermoplastic elastomer according to any one of claims 1 to 7, wherein 9. The olefin-based thermoplastic elastomer according to claim 8, wherein the kneading device is a twin-screw extruder.