JPH11269325A - Thermoplastic elastomer composition - Google Patents

Abstract

(57) [Problem] To provide a thermoplastic elastomer excellent in balance between mechanical properties such as flexibility and elastic recovery and moldability. SOLUTION: (a) An oil-extended ethylene system containing an ethylene copolymer rubber having an intrinsic viscosity [η] of 4.3 to 6.8 dl / g in a decalin solvent at 135 ° C and a mineral oil softener. Obtained by dynamically heat treating a copolymer rubber and a polymer composition containing 70% by weight or more based on 100% by weight of the total of polymer components of a copolymer rubber and an olefin resin in the presence of a crosslinking agent. Thermoplastic elastomer composition.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to a thermoplastic elastomer composition. More specifically, the present invention relates to a thermoplastic elastomer composition having an excellent balance between mechanical properties such as flexibility and elastic recovery and moldability.

[0002]

2. Description of the Related Art An olefin-based thermoplastic elastomer obtained by dynamically heat-treating an ethylene-based copolymer rubber and an olefin-based resin in the presence of a cross-linking agent does not require a vulcanization step, and a conventional thermoplastic resin is used. Molding methods such as injection molding, profile extrusion molding, calendering, and blow molding. However,
Such an olefin-based thermoplastic elastomer also has a disadvantage that elastic recovery is inferior to vulcanized rubber. Conventionally, in order to make up for these disadvantages, improvement in the crosslink density of the ethylene copolymer rubber, raising the Mooney of the ethylene copolymer rubber, and the like have been performed. Although the elastic recovery is improved by these methods, the fluidity of the obtained thermoplastic elastomer composition is significantly reduced. There is also a method of adding a peroxide-decomposable olefin-based rubber to improve the moldability, but in this case, the elastic recovery is reduced. On the other hand, when dynamically heat-treating in the presence of a cross-linking agent, the flowability of the thermoplastic elastomer composition can be improved by adding a large amount of a mineral oil-based softening agent, but the moldability deteriorates. However, there is a problem that the appearance of the extruded product is deteriorated. As described above, it is difficult for the olefin-based thermoplastic elastomer obtained by the conventional method to obtain a balance between elastic recovery and moldability.

[0003]

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and is intended to provide a thermoplastic elastomer excellent in balance between mechanical properties such as flexibility and elastic recovery and moldability. The purpose is to provide.

[0004]

Means for Solving the Problems The present inventors have conducted intensive studies to achieve the above object, and as a result, have found that an oil containing an ethylene copolymer rubber having a specific intrinsic viscosity [η] and a mineral oil softener is used. The present inventors have found that a desired thermoplastic elastomer composition can be obtained by dynamically heat-treating an extended ethylene copolymer rubber and an olefin resin in the presence of a crosslinking agent, and completed the present invention. That is, the present invention has the following configuration. [1] (A) An oil-extended ethylene-based copolymer containing an ethylene-based copolymer rubber having an intrinsic viscosity [η] of 4.3 to 6.8 dl / g in a decalin solvent at 135 ° C. and a mineral oil-based softener. Heat obtained by dynamically heat-treating a polymer composition containing a polymer rubber and (b) an olefin-based resin in an amount of 70% by weight or more based on 100% by weight of the total polymer components in the presence of a crosslinking agent Plastic elastomer composition. [2] (A) The oil-extended ethylene copolymer rubber is composed of 100 parts by weight of the ethylene copolymer rubber and the mineral oil softener 2
The thermoplastic elastomer composition according to the above [1], comprising 0 to 300 parts by weight. [3] The weight ratio ((a) / (b)) of (a) oil-extended ethylene copolymer rubber and (b) olefin resin is 20/8.
The thermoplastic elastomer composition according to the above [1] or [2], which is 0 to 95/5. [4] (1) The above [1] to [3], wherein the oil-extended ethylene copolymer rubber is obtained by removing the solvent from a mixed solution containing the ethylene copolymer rubber and the mineral oil softener. ] The thermoplastic elastomer composition according to any one of [1] to [10]. The present invention is described in detail below, and other objects, advantages and effects of the present invention will become apparent.

[0005]

BEST MODE FOR CARRYING OUT THE INVENTION The oil-extended ethylene copolymer rubber (a), which is a component of the thermoplastic elastomer composition of the present invention, comprises:
Intrinsic viscosity [η] measured at 135 ° C in decalin solvent
Contains 4.3 to 6.8 dl / g of an ethylene-based copolymer rubber and a mineral oil-based softener.

[0006] As the ethylene copolymer rubber, ethylene and α-α having 3 or more carbon atoms, preferably 3 to 8 carbon atoms, are used.
Examples include a random copolymer obtained by copolymerizing an olefin and a non-conjugated diene. Examples of the α-olefin having 3 or more carbon atoms copolymerized with ethylene include propylene, 1-butene, 1-pentene, 1-hexene, 1-heptene, 1-octene, 1-decene and the like. α
-The olefin can be used alone or in combination of two or more. Further, non-conjugated dienes to be copolymerized include dicyclopentadiene, 1,4-hexadiene, cyclooctadiene, methylene norbornene,
Examples include ethylidene norbornene, 5-methyl-1,4-hexadiene, 4-methyl-1,4-hexadiene, 6-methyl-1,5-heptadiene, and methyl-1,6-octadiene. It is also possible to give a branched structure to the ethylene-based random copolymer by a known method. Preferred diene for imparting a branched structure include 1,5-hexadiene, 1,7-octadiene,
1,9-decadiene, norbornadiene and the like can be mentioned. These non-conjugated dienes may be used alone or in combination of two or more. From the viewpoint of maintaining the mechanical strength and flexibility of the ethylene random copolymer rubber, these ethylene random copolymers are preferably 50/50 to 95/5, more preferably 50/50 to 95/5, in a molar ratio of ethylene / α-olefin. Is preferably copolymerized at 60/40 to 90/10. The content of the non-conjugated diene is preferably 12% by weight or less, more preferably 1 to 10% by weight.

The intrinsic viscosity of an ethylene copolymer rubber is determined as a value measured in a decalin solvent at a temperature of 135 ° C.
4.3 to 6.8 dl / g, preferably 4.3 to 6.0 d
1 / g, and more preferably 4.4 to 5.7 dl / g. When the intrinsic viscosity is less than 4.3 dl / g, the elastic recovery property is impaired, and when the intrinsic viscosity exceeds 6.8 dl / g, the workability during molding is impaired.

(A) The mineral oil-based softener contained in the oil-extended ethylene-based copolymer rubber is used for imparting moldability and flexibility and improving the appearance of the product. As mineral oil softeners, aromatic, naphthenic,
Paraffin-based, etc., among which paraffin-based,
Naphthenic is preferred. The amount of the mineral oil-based softener is usually 20 parts by weight based on 100 parts by weight of the ethylene-based copolymer rubber in consideration of the balance between the moldability, flexibility, heat resistance, and strength of the thermoplastic elastomer composition of the present invention. ~ 30
0 parts by weight, preferably 30 to 200 parts by weight, and 50 to 1 part by weight.
50 parts by weight is more preferable, and 80 to 150 parts by weight is most preferable.

The (a) oil-extended ethylene copolymer rubber of the present invention can be prepared by removing the solvent from a mixture containing the ethylene copolymer rubber and a mineral oil softener. The method is not particularly limited, but as a preferable method, a predetermined amount of a mineral oil-based softening agent is added to and mixed with the ethylene-based copolymer rubber mixture obtained by polymerization, and then a steam stripping method, a flash method, or the like is used. The method of removing the solvent by the method can be mentioned. After polymerization, the resulting ethylene copolymer rubber is uniformly dissolved in a good solvent such as a hydrocarbon solvent such as benzene, toluene, xylene, hexane, heptane, and cyclohexane, and a halogenated hydrocarbon solvent such as chlorobenzene to form a solution. None, add a certain amount of mineral oil softener there,
After mixing, the solvent may be removed by a method such as a steam stripping method or a flash method. The oil-extending of the ethylene copolymer rubber can also be carried out by using a device commonly used for oil-extending rubber, such as a Banbury mixer, a pressure kneader or a roll. However, since the molecular weight of the rubber before oil extension is high, it is difficult in operation to uniformly disperse the mineral oil-based softening agent in the ethylene-based copolymer rubber.

As described above, when a mineral oil-based softening agent is added to a mixed solution of an ethylene-based copolymer rubber, the softening agent is sufficiently and uniformly dispersed in the rubber. It is preferable because it does not go out. Ethylene-based copolymer rubber can be polymerized by a known polymerization method, for example, in the presence of a vanadium-based, titanium-based, or metallocene-based catalyst. Is practically preferable.

The ethylene copolymer rubbers may be used alone or
Can be used in combination of two or more. Also,
Water of ethylene copolymer rubber is used as the ethylene copolymer rubber.
Some of the elemental atoms are halogen atoms such as chlorine and bromine.
Substituted halogenated ethylene copolymer rubber or vinyl chloride
Nyl, vinyl acetate, (meth) acrylic acid or derivatives thereof
(For example, methyl (meth) acrylate, glycidyl (meth
(T) acrylate, (meth) acrylamide, etc.), male
Formic acid or its derivatives (eg maleic anhydride, maleic
Imide, dimethyl maleate, etc.), conjugated dienes (e.g.
Unsaturated metal such as tadiene, isoprene, chloroprene, etc.)
Graft-modified ethylene copolymer copolymerized with nomer
Coalescence can also be used. (A) Oil-extended ethylene type
The shape of polymerized rubber can be any of veil, crumb or pellet
These shapes may be used. Such (a) oil-extended ethylene-based
Polymerized rubber is used to examine the flexibility and elastic recovery of the resulting composition.
From the viewpoint, it is preferably amorphous or low crystalline. Conclusion
Crystallinity is related to density and generally makes crystallinity easier
Can be substituted for the density. (A) Oil exhibition d of the present invention
The density of the ethylene copolymer rubber is 0.89 g /
cm ^ThreeThe following is preferred.

The olefin resin of the component (b) is not particularly limited. Examples thereof include a homopolymer of ethylene, a crystalline ethylene copolymer containing 90 mol% or more of ethylene, and a crystalline propylene homopolymer. , 90 propylene
A crystalline propylene copolymer containing at least mol% is preferred. Specifically, high density polyethylene, low density polyethylene, ethylene / 1-butene copolymer, ethylene / 1
-Crystalline ethylene polymers such as hexene copolymers, ethylene / 1-octene copolymers; isotactic polypropylene, propylene / ethylene copolymers, propylene /
1-butene copolymer, propylene / 1-pentene copolymer, propylene / 3-methyl-1-butene copolymer, propylene / 1-hexene copolymer, propylene / 3-methyl-1-pentene copolymer , Propylene / 4-methyl-1-pentene copolymer, propylene / 3-ethyl-1
-Pentene copolymer, propylene / 1-octene copolymer, propylene / 1-decene copolymer, propylene / 1
-Undecene copolymer, propylene / 1-butene / ethylene terpolymer, propylene / 1-hexene / 1-octene terpolymer, propylene / 1-hexene / 4-
A crystalline propylene polymer whose main component is a propylene component such as a methyl-1-pentene terpolymer is exemplified.

The weight ratio of the (a) oil-extended ethylene copolymer rubber and the (b) olefin resin ((a) /
(B)) is usually from 20/80 to 95/5, preferably from 30/70 to 90/10, and more preferably from 40/70 to 90/10.
60 to 90/10. (B) When the proportion of the oil-extended ethylene copolymer rubber and the (b) olefin resin is within the above range, the thermoplastic elastomer composition of the present invention can be used to obtain mechanical properties such as flexibility and elastic recovery and molding processing. In addition to being excellent in balance with properties, it is also possible to have excellent product appearance.

The crosslinking agents used in the present invention are those generally used for crosslinking ethylene copolymer rubbers such as EPM or EPDM, for example, sulfur, sulfur compounds, organic peroxides, phenolic resin crosslinking agents, quinoids. A crosslinker, a metal acrylate crosslinker, a bismaleimide crosslinker, and the like are used. Hereinafter, these crosslinking agents will be sequentially described.

(1) Sulfur and Sulfur Compounds As the sulfur and sulfur compounds used in the present invention, those generally produced and sold for vulcanizing rubber can be used. Examples of the sulfur include powdered sulfur, sulfur, precipitated sulfur, colloidal sulfur, surface-treated sulfur and insoluble sulfur. Examples of the sulfur compound include sulfur chloride; sulfur dichloride; morpholine disulfide; alkylphenol disulfide; thioureas such as dibutylthiourea; And dithiocarbamates such as zinc dimethyldithiocarbamate, zinc diethyldithiocarbamate and sodium dimethyldithiocarbamate.

(2) Organic peroxide Examples of the organic peroxide include dicumyl peroxide,
Ditertiary butyl peroxide, 2,5-dimethyl-2,5
-Di (tert-butylperoxy) hexane, 2,5-dimethyl-di (tert-butylperoxy) hexyne-3,1,
3-bis (tert-butylperoxyisopropyl) benzene, 1,1-bis (tert-butylperoxy) -3,3,3
5-trimethylcyclohexane, n-butyl-4,4-
Bis (tert-butylperoxy) valerate, benzoyl peroxide, p-chlorobenzoyl peroxide,
Examples include 2,4-dichlorobenzoyl peroxide, tertiary butyl peroxybenzoate, tertiary butyl peroxyisopropyl carbonate, diacetyl peroxide, lauroyl peroxide, tertiary butyl peroxide and the like. Among these organic peroxides, those having a mild decomposition reaction and a more uniform mixing of the rubber and the resin component and which proceed with a crosslinking reaction are preferred. An organic peroxide having a moderate decomposition reaction can be represented by, for example, a 1-minute half-life temperature as an index, and the 1-minute half-life temperature is sufficiently high.
Those having a temperature of 150 ° C. or higher are preferred. As such an organic peroxide, for example, 2,5-dimethyl-2,5-di (third
(Butylperoxy) -hexyne-3,2,5-dimethyl-2,5-di (tert-butylperoxy) hexane,
3-bis (tert-butylperoxyisopropyl) benzene. In particular, 2,5-dimethyl- having a high decomposition temperature
Most preferred is the use of 2,5-di (tert-butylperoxy) -hexyne-3.

When an appropriate crosslinking aid is present together with an organic peroxide as a crosslinking agent, a uniform and mild crosslinking reaction can be expected. As a crosslinking aid, sulfur, p-quinone dioxime, p, p'-dibenzoylquinone dioxime, ethylene glycol dimethacrylate, diethylene glycol dimethacrylate, triethylene glycol dimethacrylate, tetraethylene dimethacrylate, polyethylene glycol dimethacrylate, Trimethylolpropane trimethacrylate, diarylphthalate, diarylphthalate, tetraaryloxyethane, triarylcyanurate, diarylphthalate, tetraaryloxyethane, triarylcyanurate,
N, N-m-phenylenebismaleimide, maleic anhydride, divinylbenzene, zinc di (meth) acrylate, aluminum tri (meth) acrylate, magnesium di (meth) acrylate and the like are used. Among them, N, Nm-phenylenebismaleimide, p, p'-dibenzoylquinonedioxime and divinylbenzene are preferred. These are 1
Species can be used alone or in combination of two or more.

The mixing ratio of these organic peroxides is preferably 0.02 to 100 parts by weight of the total amount of the ethylene-based copolymer rubber and the polyolefin-based resin component from the viewpoint of performing uniform and gentle partial crosslinking. To 1.5 parts by weight, more preferably 0.05 to 1.0 parts by weight. The compounding ratio of the crosslinking aid is preferably 3 parts by weight based on 100 parts by weight of the total amount of the ethylene copolymer rubber and the polyolefin resin.
It is not more than 0.2 parts by weight, more preferably 0.2 to 2 parts by weight. When the compounding ratio is in this range, the thermoplastic elastomer composition of the present invention maintains the uniformity of the phase structure (sea-island structure) and the moldability associated therewith. In addition, excessive use may remain in the thermoplastic elastomer composition as an unreacted monomer, and may cause a change in physical properties due to the heat history at the time of molding.

(3) Phenolic resin-based crosslinking agent Preferred phenolic resin-based crosslinking agents are compounds represented by the following general formula.

[0020]

Embedded image

Here, m is an integer of 0 to 10, and X and Y are hydroxyl groups or halogen atoms, which may be the same or different. R is a saturated hydrocarbon group having 1 to 15 carbon atoms. The above compounds are described, for example, in US Pat.
As described in the specifications of Nos. 40 and 3709840, they are generally used as crosslinking agents for rubber. And this crosslinking agent, in the presence of an alkali catalyst,
It can be produced by condensation polymerization of a substituted phenol and an aldehyde. The blending ratio of the phenolic crosslinking agent is appropriate for the degree of partial crosslinking of the thermoplastic elastomer composition of the present invention, oil resistance, shape recovery, and flexibility in order to improve the flexibility of the ethylene-based copolymer rubber. Preferably, 0.1 to 100 parts by weight of the total amount of the olefin resin.
10 to 10 parts by weight, more preferably 0.3 to 5 parts by weight, still more preferably 0.4 to 2 parts by weight. The phenolic crosslinking agent can be used alone, but can also be used in combination with a crosslinking accelerator to adjust the crosslinking rate. Organic halides such as stannous chloride, ferric chloride metal halides, chlorinated polypropylene, brominated polypropylene, brominated butyl rubber, and chloroprene rubber can be used as the crosslinking accelerator. Further, a dispersant such as a metal oxide such as zinc oxide or stearic acid may be used in combination.

(4) Quinoid Crosslinking Agent Preferred quinoid crosslinking agents include p-quinone dioxime derivatives. Specific examples include p-benzoquinone dioxime and p-dibenzoylquinone diamide. The compounding ratio of the quinoid-based cross-linking agent is preferably 0.2 to 10 parts by weight with respect to the total of 100 parts by weight of the ethylene-based copolymer rubber and the olefin-based resin for the same reason as in the case of the phenol-based cross-linking agent described above. , More preferably 0.5 to 7 parts by weight, still more preferably 0.8 to 3 parts by weight. The crosslinking agent can be used alone, but a crosslinking accelerator can be used in combination to adjust the crosslinking speed. As the crosslinking accelerator, an oxidizing agent such as lead red, dibenzothiazoyl sulfide, and tetrachlorobenzoquinone can be used. Further, a metal oxide such as zinc oxide or a dispersant such as stearic acid may be used.

(5) Metal Acrylate Crosslinking Agent The metal acrylate crosslinker is a metal salt of zinc or calcium such as acrylic acid or methacrylic acid. Usually, it is obtained, for example, by reacting zinc oxide or zinc carbonate with methacrylic acid. Specifically, zinc dimethacrylate, calcium dimethacrylate, magnesium dimethacrylate,
Monohydroxyaluminum dimethacrylate, aluminum trimethacrylate, calcium diacrylate, magnesium diacrylate, monohydroxyaluminum diacrylate, aluminum triacrylate, and the like.
The preferred amount of the metal acrylate cross-linking agent when dynamically heat-treating the metal acrylate cross-linking agent as a main component is based on a total of 100 parts by weight of the ethylene copolymer rubber and the olefin resin, Preferably it is 1 to 20 parts by weight, more preferably 4 to 12 parts by weight. (6) Bismaleimide-based crosslinker The bismaleimide-based crosslinker usually used is
N, N'-m-phenylenebismaleimide. Bismaleimide-based crosslinking agents are usually used as a crosslinking aid for organic peroxide crosslinking, but it is known that a crosslinking reaction occurs even when used alone. The preferred compounding ratio of the bismaleimide-based crosslinking agent is 0.05 to 10 with respect to 100 parts by weight of the total of the ethylene-based copolymer rubber and the olefin-based resin.
Parts by weight, more preferably 0.1 to 5 parts by weight, even more preferably 0.2 to 2 parts by weight.

The thermoplastic elastomer composition of the present invention may contain, depending on its use, antioxidants, antistatic agents, weather stabilizers, and the like in amounts that do not substantially impair the characteristics of the composition.
UV absorber, lubricant, antiblocking agent, sealant, crystal nucleating agent, flame retardant, antibacterial agent, fungicide, tackifier, softener, plasticizer, coloring agent (titanium oxide, carbon black Etc.), fillers (glass fiber, carbon fiber, metal fiber, aramid fiber, glass beads, mica, calcium carbonate, potassium titanate whisker, talc, barium sulfate, glass flake, fluororesin, etc.) may be appropriately compounded. it can. In addition, rubbery polymers (butyl rubber, N
Polymers such as BR, thermoplastic resins, and thermoplastic elastomers (such as low-crystalline propylene-based polymers and hydrogenated diene-based polymers) can be appropriately blended. These polymers are
The components (a) and (b) may be blended when dynamically heat-treating in the presence of a cross-linking agent, or the components (a) and (b) may be dynamically mixed in the presence of a cross-linking agent. After heat treatment. The compounding amount of the polymer components other than the component (a) and the component (b) is less than 30% by weight based on 100% by weight of the total of the polymer components. In addition, the mineral oil-based softening agent may be further added to the thermoplastic elastomer composition of the present invention, for example, at the stage of dynamic heat treatment, as long as bleeding does not occur.

The thermoplastic elastomer composition of the present invention comprises:
(B) It is obtained by dynamically subjecting an oil-extended ethylene copolymer rubber and (b) a polyolefin resin to heat treatment in the presence of the crosslinking agent. In the present invention, the term "dynamically heat-treating" means that the components (a) and (b) are simultaneously melt-kneaded / dispersed and the component (a) is subjected to a crosslinking reaction in the presence of a crosslinking agent. By performing such an operation, an olefin-based thermoplastic elastomer composition having a sea-island structure in which the component (a) partially or completely cross-linked floats in the component (ii) is obtained.
The temperature condition of the dynamic heat treatment is preferably in the range of 150 ° C. to 250 ° C. which has a good balance between the melting of the component (b) and the crosslinking reaction.

The apparatus used for the above dynamic heat treatment includes a batch kneader such as a pressure kneader, a Banbury mixer, and a Brabender, a single screw extruder, a twin screw extruder,
A continuous kneader such as a continuous kneader and a feeder / ruder, and a combination of these devices. For example, the thermoplastic elastomer composition of the present invention can be obtained by the devices and methods described below. The component (a) and the component (b) are kneaded by the above-mentioned batch kneader, and the temperature is set to a temperature at which the components (a) and (b) are sufficiently melted. The components (a) and (b) are sufficiently blended using the batch kneader at a temperature at which the components (a) and (b) are sufficiently melted (first stage). Using a continuous kneader, the first-stage blend and a crosslinking agent are charged and dynamically heat-treated (second stage). The component (a), the component (b) and the crosslinking agent are charged into a continuous kneader and dynamically heat-treated. In the above description, the additional mineral oil-based softener, various additives, and the like may be added at any stage. Any of these methods may be used as long as the component (a) and the component (b) are in a molten state and dynamically heat-treated in the presence of a cross-linking agent without exceeding the gist of the present invention. It is not limited.

[0027]

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. In the examples, parts and percentages are by weight unless otherwise specified. Various measurements in the examples were based on the following methods.

(1) JIS A hardness Measured according to JIS K6301. (2) Elastic recovery The compression set was used as an index of the elastic recovery. As the measurement conditions, a compression set at 25% compression at 70 ° C. for 22 hours was measured. The smaller the compression set, the better the elastic recovery. (3) Tensile strength and maximum elongation Measured according to JIS K6301. (4) Fluidity MFR (melt flow rate) was measured under the following conditions and used as a measure of fluidity. Temperature: 230 ° C., load: 10 kg (5) Moldability Injection moldability and extrusion moldability were evaluated. Injection moldability: Flat plates were injection molded with a 6.5 ounce injection molding machine manufactured by Nippon Steel Corporation. The sink, burn, and mold transferability of the molded product were evaluated on the following three levels. 〇: No sink marks and burns, and the mold mirror surface was sufficiently transferred. Δ: Any of slight sink marks, burns, and insufficient mold transfer occurred. ×: One of the phenomena of serious sink marks, burns, and insufficient mold transfer has occurred. Extrudability: 30mm extruder manufactured by Nakatani Machine Co., Ltd.
A die was attached and the sheet was formed, and the surface skin was evaluated in the following three stages. 〇: The surface is sufficiently smooth. Δ: The surface is slightly rough or sharkskin is generated. ×: Melt fracture has occurred.

Each component used in the present Examples and Comparative Examples will be described. (1) Oil-extended ethylene-based copolymer rubber The ethylene-propylene-diene random copolymer rubber, mineral oil-based softener used and the oil extension amount are shown in Table 1 below.

[0030]

[Table 1] In the column of diene, ENB and DCP indicate the following compounds, respectively. ENB: ethylidene norbornene DCP: dicyclopentadiene Oil extension (PHR) means the blending amount (parts by weight) of a mineral oil-based softening agent with respect to 100 parts by weight of rubber.

The oil-extended ethylene / propylene / diene random copolymer rubbers (EP-1 to EP-6) shown in Table 1 above were prepared by the following method. Into a 3-liter separable flask previously purged with nitrogen, 2 liters of dehydrated and purified n-hexane was charged, and ethylene gas, propylene gas, and hydrogen gas purified through a molecular sieve were flowed at a rate of 6/4/1 (volume ratio). The mixture was fed in a gas phase at a ratio and dissolved at room temperature for 10 minutes with stirring. Next, a diene component, aluminum sesquichloride (Al
(Et _1.5 Cl _1.5 ) and 5 mmol of vanadium oxytrichloride (VOCl ₃ ) were charged to initiate polymerization. The reaction temperature was adjusted to 20 ° C. while feeding an ethylene gas, a propylene gas, and a hydrogen gas in a gas phase, and the polymerization reaction was continued. Twenty minutes after the start of the polymerization, the catalyst was deactivated with isopropyl alcohol purified by molecular sieve, and the polymerization was stopped. After blending a predetermined amount of a mineral oil-based softener in the obtained copolymer solution,
After precipitating these components in methanol,
It was dried with a hot roll at 00 ° C. to obtain an oil-extended copolymer rubber.

(2) Polyolefin resin PP-1: polypropylene [trade name: MA-03 manufactured by Nippon Polychem Co., Ltd.] PP-2: random polypropylene [trade name: MG-03A manufactured by Nippon Polychem Co., Ltd.] PP-3: block polypropylene [ Product name: BC-03C manufactured by Nippon Polychem Co., Ltd. PP-4: Random polypropylene [Product name: EX-6 manufactured by Nippon Polychem Co., Ltd.] PE: Linear low-density polyethylene [Product name: UJ370 manufactured by Nippon Polychem Co., Ltd.] (3) Mineral oil-based softener oil-1: Paraffin-based oil [Idemitsu Kosan Co., Ltd., trade name:
PW-380] oil-2: naphthenic oil [trade name: N, manufactured by Idemitsu Kosan Co., Ltd.]
S-100] (4) Crosslinking agent Crosslinking agent 1: 2,5-dimethyl-2,5-di (tert-butylperoxy) -hexyne-3 [trade name, manufactured by NOF Corporation:
Perhexin 25B] Cross-linking agent 2: N, N-m-phenylenebismaleimide (trade name, manufactured by Ouchi Shinko Co., Ltd .: Barnock PM) Cross-linking agent 3: alkylphenol formaldehyde (trade name, manufactured by Taoka Chemical Co., Ltd .: Tackirol 201) Cross-linking agent 4: Brominated alkylphenol formaldehyde [Taoka Chemical Co., Ltd. product name: Tackilol 250] Crosslinking agent 5: p-benzoquinone dioxime [Kawaguchi Chemical Co., Ltd. product name: Actor Q] Crosslinking agent 6: Tetrachlorobenzoquinone [Kawaguchi Chemical Co., Ltd. product name : Actor CL] Crosslinking agent 7: Zinc dimethacrylate [manufactured by Asada Chemical Co., Ltd.]

(5) Additive Additive 1: Divinylbenzene [manufactured by Sankyo Kasei Co., Ltd.] Additive 2: chlorinated polyethylene [Product name: Eraslen 301A manufactured by Showa Denko KK] Additive 3: No. 1 zinc flower [Hakusui Chemical Co., Ltd.] Product name: 2 kinds of zinc white] Additive 4: Stearic acid [Product name: Lunac S30] (6) Other polymers (i) Hydrogenated diene copolymer Hydrogenated SBR: [Products manufactured by JSR Co., Ltd. Name: Dynaron 1320P] CEBC: [JR Product Name: Dynaron 6200P] SEBS: [Shell Chemical Company Name: Krayton
G 1657] SEPS: [Product name: SEPTON 20 manufactured by Kuraray Co., Ltd.]
07] (ii) Low crystalline α-olefin polymer APAO: [trade name: Ube Tack, manufactured by Ube Lexen Co., Ltd.]
APAO 2528]

Examples 1 to 25, Comparative Examples 1 to 10 Compositions were prepared according to the following procedures according to the formulation shown in Tables 2 to 6. That is, a polymer, a softening agent, and the like were charged into a pressurized kneader (manufactured by Moriyama Seisakusho Co., Ltd., 10 L in internal volume) in which the temperature in the bath was set at 180 ° C., melt-mixed, and discharged. The discharged composition was continuously extruded using a feeder ruder, and was subjected to strand cutting to prepare a master batch pellet. A blend of the obtained masterbatch pellets and a crosslinking agent is subjected to a dynamic heat treatment continuously and dynamically using a twin-screw extruder (trade name: PCM-45, manufactured by Ikegai Co., Ltd.) to obtain a thermoplastic elastomer composition. Was. Except for Example 4, among the test samples, pellets of the obtained composition were formed into 2 mm-thick sheets using a 6.5 oz. Injection molding machine and subjected to various tests. For Example 4, a pellet of the composition was rolled into a 6-inch electric heating roll (temperature: 180 ° C.).
, And a sheet having a thickness of 2 mm was prepared by an electric heat press and subjected to various tests. Regarding the evaluation of JIS-A hardness and compression set, a test piece having a thickness of 2 mm produced by the injection molding machine or press molding machine was used. Provided. Further, with respect to the evaluation of the tensile strength and the maximum elongation, a predetermined test piece was punched out of the sheet with a dumbbell cutter and used for the test. The results are shown in Tables 2 to 6.

[0035]

[Table 2]

[0036]

[Table 3]

[0037]

[Table 4]

[0038]

[Table 5]

[0039]

[Table 6]

Examples 1 to 8 are examples in which a propylene-based resin is used among various ethylene-based copolymer rubbers and polyolefin-based resins within the scope of the present invention, and Example 4 is particularly used for profile extrusion. It is. Comparative examples 1, 3, 8, 9 using propylene resin and ethylene copolymer rubber outside the scope of the present invention (Comparative examples 1, 3 are for injection molding, Comparative examples 8 and 9 are profile extrusion Comparison of the compositions of the present invention with those of the present invention, respectively, shows that the compositions of Examples within the scope of the present invention have excellent compression set and tensile strength. In Examples 1 and 9 to 11, various hardnesses were adjusted by using an ethylene copolymer rubber within the scope of the present invention. When this is compared with those of Comparative Examples 1 and 5 to 7 each having the same hardness by using an ethylene copolymer rubber outside the range of the present invention, the thermoplastic elastomer composition within the range of the present invention Has excellent compression set, tensile strength and moldability (injection moldability) as compared with the composition of Comparative Example. Examples 12 to 14, 17, and 18
In the scope of the present invention, those using the same polymer composition as in Example 2 and using various partial cross-linking crosslinking agents are exemplified. In these compositions, although there are some differences in physical properties based on the crosslinked system, a thermoplastic elastomer composition excellent in elastic recovery, mechanical strength, and moldability is obtained as in Example 2. Examples 15, 16, and 19 show a cross-linking system of complete cross-linking using an ethylene-based copolymer rubber within the scope of the present invention. Examples 15 and 16 show that a polypropylene-based resin was used as a polyolefin resin. Are those using a polyethylene resin as the olefin resin. This was compared with Comparative Examples 2, 4, and 10 (Comparative Examples 2, 4) using an ethylene copolymer rubber outside the scope of the present invention.
4, the thermoplastic elastomer composition within the scope of the present invention is excellent in elastic recovery and mechanical strength, as compared with polypropylene resin and Comparative Example 10 using polyethylene resin. In Examples 20 to 25, various polymers and mineral oil softeners were additionally added as the other components to the polymer composition of Example 1 and dynamically heat-treated. It can be seen that these compositions are excellent in elastic recovery, mechanical strength, and moldability as in Example 1. These comparisons show that the thermoplastic elastomer composition of the present invention has an excellent balance between elastic recovery, mechanical strength and moldability. Among the compositions of the comparative examples, EP-6, which is an ethylene copolymer rubber, has an intrinsic viscosity [η] of less than the lower limit of the range of the present invention. Comparative Example 1
The ethylene copolymer rubber corresponds to Example 1 except that EP-6 was used instead of EP-1 of Example 1, but the intrinsic viscosity [η] of the ethylene copolymer rubber used was Is less than the lower limit of the range of the present invention, so that compression set, tensile strength and maximum elongation are poor. Also E
P-7 is a non-oil-extended rubber. Comparative Example 3, Comparative Example 4 and Comparative Example 9 used EP-7 as an ethylene copolymer rubber, Comparative Example 3 was Example 8, and Comparative Example 4 was Example 16.
Comparative Example 9 substantially corresponds to each of Example 4. However, even when the amount of the mineral oil-based softening agent contained in the thermoplastic elastomer composition is the same, EP as ethylene copolymer rubber is used. -7, the use of a non-oil-extended rubber such as mineral oil-based softening agent at the time of dynamic crosslinking, the same amount as in each example, compression set in any composition,
It can be seen that the tensile strength and the maximum elongation are poor.

[0041]

According to the present invention, it is possible to provide a thermoplastic elastomer composition having an excellent balance between elastic recovery and molding processability by molding with a processing apparatus used for a general thermoplastic resin. It is. Therefore, it can be suitably used for interior and exterior parts of automobiles, parts such as packing housings of weak electric parts, industrial parts, waterproof sheet parts, gasket seal parts, etc., in which soft vinyl chloride resin or vulcanized rubber is used. I can do it.

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor: Satoshi Yamashita, Jie S.R. Inside (72) Inventor Kenji Yasuda Inside JSR Co., Ltd. 2-11-24 Tsukiji, Chuo-ku, Tokyo

Claims (4)

[Claims] 1. An oil-extended ethylene containing an ethylene copolymer rubber having an intrinsic viscosity [η] of 4.3 to 6.8 dl / g in a decalin solvent at 135 ° C. and a mineral oil softener. A polymer composition containing a copolymer rubber and 70% by weight or more based on 100% by weight of a total of the polymer components of a (B) olefin resin is dynamically heat-treated in the presence of a crosslinking agent. Thermoplastic elastomer composition. 2. The thermoplastic resin according to claim 1, wherein (a) the oil-extended ethylene copolymer rubber contains 100 parts by weight of the ethylene copolymer rubber and 20 to 300 parts by weight of the mineral oil softener. Elastomer composition. 3. A weight ratio of (a) an oil-extended ethylene copolymer rubber and (b) an olefin resin ((a) / (b))
Is from 20/80 to 95/5. The thermoplastic elastomer composition according to claim 1 or 2, wherein 4. The oil-extended ethylene copolymer rubber is obtained by removing a solvent from a mixed solution containing the ethylene copolymer rubber and the mineral oil softener.
The thermoplastic elastomer composition according to any one of the above.