JP2003246889A - Thermoplastic elastomer composition and molded article - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a thermoplastic elastomer composition which serves as a substitute for an NBR/PVC composition, has good oil resistance and is excellent in rubber elasticity and moldability, and its molded article. <P>SOLUTION: The thermoplastic elastomer composition is obtained by subjecting a mixture containing (A) an unsaturated nitrile-conjugated diene rubber having two or more glass transition temperatures and a content of unsaturated nitrile units of 25-50 wt.% and (B) an olefin resin to a dynamic heat treatment in the presence of a crosslinking agent. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a thermoplastic elastomer composition. More specifically, a mixture containing a specific unsaturated nitrile-conjugated diene rubber and an olefin resin is subjected to a dynamic heat treatment in the presence of a cross-linking agent to obtain excellent oil resistance, excellent rubber elasticity, and molding processing. TECHNICAL FIELD The present invention relates to a thermoplastic elastomer composition having good properties and a molded article thereof.

[0002]

2. Description of the Prior Art Nitrile rubbers such as acrylonitrile-butadiene copolymer rubber (NBR) contain polar groups, and therefore have excellent oil resistance against hydrocarbon oils such as non-polar oils such as gasoline. However, since the main chain contains a double bond, the weather resistance is poor and the application is limited. In order to improve the weather resistance of nitrile rubber, there is a method of mixing with vinyl chloride polymer (PVC) or a method of vulcanizing the mixture, which is often used for automobiles, industrial parts, etc. that currently require oil resistance. Has been done. However, because PVC is difficult to recycle and use, P
The number of companies refraining from using VC is increasing, and development of materials replacing PVC is required. As one of them, there is a method of melt-mixing a nitrile rubber and an olefin resin and then crosslinking the nitrile rubber. However, the compatibility of the nonpolar olefin resin and the polar nitrile rubber is extremely poor, and when the crosslinked nitrile rubber is dispersed in the olefin resin, the dispersed particle size becomes large and the physical properties are not improved. The appearance of the molded product was poor. Therefore, methods of adding various compatibilizers have been devised (for example, JP-A-56-143233 and JP-B-4-48817).
Etc., the physical properties are improved but the appearance of the molded product is not improved.

[0003]

The object of the present invention has been made in view of the above problems of the prior art. NBR / PVC
As an alternative to the composition, it has oil resistance and rubber elasticity,
It is intended to provide a thermoplastic elastomer composition excellent in molding processability and a molded article thereof.

[0004]

Means for Solving the Problems As a result of intensive studies to achieve the above object, the present inventors have found that a specific unsaturated nitrile-
It was found that a thermoplastic elastomer composition having excellent oil resistance, rubber elasticity, and moldability can be obtained by dynamically heat-treating a mixture of a conjugated diene rubber and an olefin resin in the presence of a cross-linking agent, thus completing the present invention. Came to do.

The present invention provides the following thermoplastic elastomer composition and molded articles using the same. [1] A mixture containing (A) an unsaturated nitrile-conjugated diene rubber having two or more glass transition temperatures and an unsaturated nitrile unit content of 25 to 50% by weight, and (B) an olefin resin. Is obtained by dynamically heat treating in the presence of a crosslinking agent. [2] The above (A) unsaturated nitrile-conjugated diene rubber 5
The thermoplastic elastomer composition according to [1] above, which contains 0 to 95% by weight and (B) an olefin resin of 50 to 5% by weight (however, the total amount of (A) and (B) is 100% by weight). object. [3] The unsaturated nitrile-conjugated diene rubber (A) has an unsaturated nitrile unit content of 30 to 70% by weight and an unsaturated nitrile unit content of 30 to 70% by weight. Is 5 to 25% by weight of an unsaturated nitrile-conjugated diene rubber (b), the thermoplastic elastomer composition as described in [1] or [2] above. [4] The ratio of the unsaturated nitrile-conjugated diene rubber (a) to the unsaturated nitrile-conjugated diene rubber (ii) is a weight ratio ((ii) / (ii)) of 1.5 to 20. The thermoplastic elastomer composition according to the above [3], wherein the thermoplastic elastomer composition is present. [5] The unsaturated nitrile-conjugated diene rubber (A) has a methyl ethyl ketone insoluble content of 10 at 23 ° C.
95% is the thermoplastic elastomer composition according to the above [1] to [4]. [6] A molded article containing the thermoplastic elastomer composition according to any one of [1] to [5] above.

[0006]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the thermoplastic elastomer composition of the present invention will be specifically described below. The thermoplastic elastomer composition of the present invention has (A) two or more glass transition temperatures and a content of unsaturated nitrile units of 25 to.
A thermoplastic elastomer composition obtained by dynamically heat-treating a mixture containing 50% by weight of an unsaturated nitrile-conjugated diene rubber and (B) an olefin resin in the presence of a crosslinking agent. Is characterized by. Hereinafter, each configuration will be described more specifically.

Unsaturated Nitrile-Conjugated Diene Rubber The unsaturated nitrile-conjugated diene rubber (A) used in the present invention has two or more glass transition temperatures and a content of unsaturated nitrile units of 25 to 50. It is an unsaturated nitrile-conjugated diene rubber (hereinafter also referred to as “component (A)”) in a weight percentage.

The unsaturated nitrile-conjugated diene rubber (A) of the present invention is a copolymer rubber of a conjugated diene and an unsaturated nitrile, and a copolymerizable polymer containing a conjugated diene, an unsaturated nitrile and a polar group other than the unsaturated nitrile. It is a copolymer rubber with a monomer and / or a polyfunctional unsaturated monomer, or a copolymer rubber obtained by polymerizing these and then partially hydrogenating.

As the conjugated diene constituting the component (A) (hereinafter also referred to as "component (a-1)"), butadiene,
Isoprene, 1,3-hexadiene, 2-methyl-1,
Examples thereof include 3-butadiene, 2,3-dimethylbutadiene, 2-trimethoxysilyl-1,3-butadiene, 1,3-pentadiene, and 2,4-dimethyl-1,3-butadiene. Of these, They may be used alone or in combination of two or more. Of these, butadiene and isoprene are particularly preferable.

Examples of the unsaturated nitrile constituting the component (A) (hereinafter also referred to as "component (a-2)") include acrylonitrile, methacrylonitrile, ethylacrylonitrile, isopropylacrylonitrile, chloroacrylonitrile and fluoroacrylonitrile. Particularly preferred is acrylonitrile.

Specific examples of the polar group-containing copolymerizable monomer other than the unsaturated nitrile which constitutes the component (A) (hereinafter also referred to as "component (a-3)") include methyl acrylate,
Ethyl acrylate, n-propyl acrylate, isopropyl acrylate, n-butyl acrylate, t acrylate
-Butyl, s-butyl acrylate, 2-methylbutyl acrylate, 3-methylbutyl acrylate, acrylic acid n
-Hexyl, n-heptyl acrylate, n-acrylic acid
Octyl, 2-ethylhexyl acrylate, acrylamide, N-hydroxymethyl (meth) acrylamide,
N- (2-hydroxyethyl) (meth) acrylamide, N, N-bis (2-hydroxyethyl) (meth) acrylamide, 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate,
Crotonic acid 2-hydroxyethyl, crotonic acid 2-hydroxypropyl, cinnamic acid 2-hydroxyethyl, cinnamic acid 2-hydroxypropyl, crotonic acid N-hydroxymethylamide, crotonic acid N- (2-hydroxyethyl) amide, Cinnamic acid N-hydroxymethylamide, cinnamic acid N- (2-hydroxyethyl) amide, allyl alcohol, o-hydroxystyrene, m-hydroxystyrene, p-hydroxystyrene, ethylene glycol mono (meth) acrylate, propylene glycol Mono (meth) acrylate, vinylamine, allylamine,
o-aminostyrene, m-aminostyrene, p-aminostyrene, 2-aminoethyl (meth) acrylate, 2
-Aminopropyl (meth) acrylate, glycidyl (meth) acrylate, allyl glycidyl ether, acrolein, vinyl methyl ketone, divinyl phthalate, diallyl phthalate, NN-methylene bis (meth)
Acrylamide, N, N-ethylenebis (meth) acrylamide, NN-hexamethylenebis (meth) acrylamide, (meth) acrylic acid, crotonic acid, cinnamic acid,
Itaconic acid, maleic acid, fumaric acid, citraconic acid, mesaconic acid, 2-hydroxyethyl (meth) acrylate,
(Meth) acrylic acid, 2-hydroxybutyl methacrylate, 2-hydroxyethyl (meth) acrylate, 2-hydroxybutyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, dimethylamino (meth) acrylate Di (meth) acrylate of ethyl, diethylaminoethyl (meth) acrylate, ω-carboxy-polycaprolactone mono (meth) acrylate, tetrahydrofurfuryl acrylate, polyethylene glycol polyalkylene glycol (the number of alkylene glycol units is, for example, 2 to 23). Examples thereof include polyalkylene glycol of polypropylene glycol (the number of alkylene glycol units is, for example, 2 to 23), di (meth) acrylate, and the like. These monomers may be used alone or in combination of two or more. Among these, acrylic acid, ethyl acrylate, n-butyl acrylate, t-butyl acrylate, and s-butyl acrylate are particularly preferable.

The content of the component (a-1) in the component (A) is
When (a-1) + (a-2) + (a-3) = 100% by weight, 15 to 75% by weight, more preferably 20 to 7% by weight
It is 0% by weight. When the content of the component (a-1) is less than 15% by weight, the rubber elasticity of the thermoplastic elastomer composition finally obtained tends to decrease. On the other hand, if it exceeds 75% by weight, the oil resistance of the finally obtained thermoplastic elastomer tends to deteriorate.

The content of the component (a-2) in the component (A) is
It is 25 to 50% by weight, more preferably 30 to 45% by weight. When the content of the component (a-2) is less than 25% by weight, the oil resistance of the finally obtained thermoplastic elastomer composition tends to decrease. On the other hand, if the content of the component (a-2) exceeds 50% by weight, the rubber elasticity of the thermoplastic elastomer composition may be finally lowered.

The content of the component (a-3) in the component (A) is
It is 0 to 60% by weight, more preferably 0 to 50% by weight. When the content of the component (a-3) exceeds 60% by weight, the rubber elasticity of the thermoplastic elastomer finally obtained tends to decrease.

The copolymer rubber of the component (A) of the present invention comprises the above-mentioned components (a-1) and (a-2) or (a-).
A polyfunctional unsaturated monomer may be copolymerized with the component (1), the component (a-2) and the component (a-3). The polyfunctional unsaturated monomer (hereinafter, also referred to as “(X) component”) has two or more radically polymerizable vinyl groups in one molecule and can be polymerized by ordinary emulsion polymerization. . Examples thereof include polyallyl compounds, methacrylate compounds, divinyl compounds, bismaleimide compounds, okiim compounds and the like. Specific examples of the polyfunctional compound include, for example, triallyl isocyanurate, trimethylolpropane trimethacrylate, N, N′-m-phenylene bismaleimide, ethylene glycol dimethacrylate, and 1,3.
-Butanediol dimethacrylate, 1,4-butanediol dimethacrylate, 1,6-hexanediol dimethacrylate, polyethylene glycol dimethacrylate, 1,4-butanediol diacrylate, 1,6-hexanediol dimethacrylate Acrylate 2,
2'-bis (4-methacryloyldiethoxyphenyl)
Propane, trimethylolpropane triacrylate,
Pentaerythritol triacrylate, divinylbenzene, N, N'-methylenebisacrylamide, p-quinonedioxime, p, p'-dibenzoylquinonedioxime, triazinethiol, triallyl cyanurate,
Examples include bismaleimide. These may be used alone or in combination of two or more.

In this case, the content of the component (X) in the component (A) is (a-1) + (a-2) + (a-3) = 100.
The amount is 0.1 to 15 parts by weight, more preferably 0.3 to 10 parts by weight, and still more preferably 0.5 to 5 parts by weight. In the rubber obtained by copolymerizing the component (X) (hereinafter, also referred to as “partially crosslinked rubber”), the molecular chains are crosslinked. The degree of crosslinking is represented by methyl ethyl ketone insoluble matter at 23 ° C. (hereinafter, also referred to as “MEK insoluble matter”), and in the component (A) of the present invention, the insoluble matter is 10 to 99%, preferably 15 to 95%. , And more preferably 20 to 90%.

The partially hydrogenated copolymer rubber contained in the component (A) of the present invention is obtained by using the above unsaturated nitrile-conjugated diene rubber as a metal complex or metal such as Ni, Pd, Pt, Rh, Ru. It is partially hydrogenated under hydrogen pressure using a hydrogenation catalyst of the compound.

The (A) unsaturated nitrile-conjugated diene rubber of the present invention is required to have two or more glass transition temperatures (Tg). A single copolymer may have two or more glass transition temperatures, or two or more unsaturated nitrile-conjugated diene rubbers having different glass transition temperatures may be used, but the latter is easier to produce. Is preferred. Of the two or more glass transition temperatures, one glass transition temperature is
It is preferably −50 ° C. or higher. T above -50 ° C
If g is not present, the oil resistance may deteriorate. Another glass transition temperature is preferably below -50 ° C.
If there is no Tg of less than -50 ° C, the compatibility with the olefin resin is extremely poor, and when dispersed in the olefin resin, the dispersed particle size of the unsaturated nitrile-conjugated diene rubber becomes large and mechanical properties , The molding appearance is inferior. Further, of the two or more glass transition temperatures, the temperature difference (ΔTg) between the glass transition temperature of the copolymer having a high glass transition temperature and the glass transition temperature of the copolymer having a low glass transition temperature is preferably 1
The temperature is 0 ° C or higher, more preferably 20 ° C or higher. ΔTg
Is less than 10 ° C, the compatibility with the olefin resin is extremely poor, and when dispersed in the olefin resin, the dispersed particle size of the unsaturated nitrile-conjugated diene rubber becomes large and mechanical properties and molding appearance are Inferior.

The molecular weight of the (A) unsaturated nitrile-conjugated diene rubber of the present invention is not particularly limited, but the Mooney viscosity (ML _{1 + 4} , 100 ° C.) is preferably 20 to 200.
When the Mooney viscosity is less than 20, rubber elasticity of the thermoplastic elastomer composition finally obtained is poor, and when it exceeds 200, the molding processability of the thermoplastic elastomer composition finally obtained tends to be poor.

The method for producing the (A) unsaturated nitrile-conjugated diene rubber of the present invention is not particularly limited, and during polymerization, for example, the conjugated diene as a monomer and the unsaturated nitrile are dividedly added to the polymerization system. It may be a single copolymer rubber having a composition distribution, or can be produced by mixing unsaturated nitrile-conjugated diene rubbers having different glass transition temperatures. As a preferred embodiment, an unsaturated nitrile-conjugated diene rubber having an unsaturated nitrile unit content of 30 to 70% by weight (hereinafter also referred to as "(a) component") and an unsaturated nitrile unit content of 5 to 25% by weight. % Of unsaturated nitrile-conjugated diene rubber (hereinafter “(b)
(Also referred to as “component”) can be easily produced. At that time, the ratio of the unsaturated nitrile-conjugated diene rubber (a) and the unsaturated nitrile-conjugated diene rubber is 1.5 to 20 in a weight ratio ((a) / (b)). preferable. When a partially crosslinked rubber is used, it may be either or both of the component (a) and the component (b). By using partially crosslinked rubber,
The extrusion processability of the finally obtained thermoplastic elastomer composition is further improved. There is no particular limitation on the mixing method of these unsaturated nitrile-conjugated diene rubbers.
One kind of latex-state or solution-state unsaturated nitrile-conjugated diene rubber may be mixed, or two kinds of solid unsaturated nitrile-conjugated diene rubber may be mixed.

The polymerization mode itself of the unsaturated nitrile-conjugated diene rubber is not particularly limited and may be any of emulsion polymerization, suspension polymerization, solution polymerization and bulk polymerization, but emulsion polymerization is general. Examples of the radical polymerization initiator used for the polymerization include organic peroxides such as benzoyl peroxide, lauroyl peroxide, cumene hydroperoxide, p-menthane hydroperoxide, and di-t-butyl peroxide, azobisisobutyronitrile, and azobisisonitrile. Valeronitrile, azo compounds such as azobisisocapronitrile, inorganic peroxides such as potassium persulfate, ammonium persulfate, hydrogen peroxide, the organic peroxides or inorganic peroxides and organic amines, ferrous sulfate, Examples thereof include redox catalysts comprising a reducing agent such as sodium sulfite, sodium thiosulfate, sodium formaldehyde sulfoxylate, L-ascorbic acid and sulfinic acid.

As the emulsifier used in the emulsion polymerization, anionic surfactants, nonionic surfactants, cationic surfactants, amphoteric surfactants and the like can be used, but especially anionic surfactants. Activators and nonionic surfactants are preferred. These surfactants can also be fluorosurfactants.

In emulsion polymerization, the following suspension stabilizers or thickeners can be used together with emulsifiers in order to adjust the viscosity and particle size of the reaction system. Specific examples include polyvinyl alcohol and polyacryl. Sodium acid, methyl vinyl ether-maleic anhydride copolymer,
It is a water-soluble suspension stabilizer such as water-soluble polyether, hydroxyethyl cellulose, carboxymethyl cellulose, starch, gelatin, casein, and alginate. These suspension stabilizers or thickeners may be included in the finally obtained thermoplastic elastomer composition.

The compounding amount of the component (A) of the present invention is 50 when the total amount of the component (B) and the olefin resin is 100% by weight.
It is possible to be 95 to 95% by weight, more preferably 55 to 90% by weight, and still more preferably 60 to 85% by weight.
When the content of the component (A) is less than 50% by weight, the oil resistance of the thermoplastic elastomer finally obtained tends to deteriorate. On the other hand, when it exceeds 95% by weight, the content of the (B) olefin resin decreases, and the phase structure (morphology) of the finally obtained thermoplastic elastomer composition is a characteristic of the dynamically crosslinkable thermoplastic elastomer. A good sea-island structure may not be formed, and molding processability and mechanical properties may deteriorate.

Olefin Resin (B) Used in the Present Invention
Examples of the olefin resin (hereinafter also referred to as “component (B)”) include homopolymers or copolymers of α-olefins having 2 to 20 carbon atoms. Specific examples of the olefin resin include the following (co) polymers. (1) Ethylene homopolymer (manufacturing method may be low pressure method or high pressure method) (2) ethylene and 10 mol%
Copolymers with the following other α-olefins or vinyl monomers such as vinyl acetate and ethyl acrylate (3) Propylene homopolymer (4) Random copolymers of propylene and 20 mol% or less of other α-olefins (5) Block copolymer of propylene and 30 mol% or less of other α-olefin (6) 1-butene homopolymer (7) Random of 1-butene and 10 mol% or less of other α-olefin Copolymer (8) 4-methyl-1-pentene homopolymer (9) Random copolymer of 4-methyl-1-pentene with 20 mol% or less of other α-olefin , Specifically, ethylene, propylene, 1
-Butene, 4-methyl-1-pentene, 1-hexene, 1-
Examples include octene. Among the above-mentioned olefin resins, propylene homopolymers and random copolymers of propylene and 20 mol% or less of other α-olefins are particularly preferable. The olefin resin as described above is solely
Alternatively, they can be used in combination.

When the olefin resin used in the present invention is a crystalline olefin resin, the crystallinity determined by X-ray method is usually 50% or more, preferably 55% or more. The density is 0.89 g / cm ³ or higher, more preferably at maximum peak temperature by differential scanning calorimetry it is preferable that the crystalline olefin resin be 0.90~0.94g / cm ^3, i.e. the melting point (hereinafter , Simply referred to as “T _m ”, is preferably 100 ° C. or higher (more preferably 120 ° C. or higher). When _Tm is less than 100 ° C, sufficient heat resistance and mechanical strength tend not to be exhibited. Also,
Melt flow rate (hereinafter simply referred to as "MFR")
(At a temperature of 230 ° C. and a load of 2.16 kg) is preferably 0.1 to 100 g / 10 minutes, more preferably 0.5.
~ 80 g / 10 minutes. If the MFR is less than 0.1 g / 10 minutes, the kneading processability and extrusion processability of the elastomer composition tend to be insufficient. On the other hand, if it exceeds 100 g / 10 minutes, the strength tends to decrease.

Therefore, the olefin resin used in the present invention has a crystallinity of 50% or more and a density of 0.89 g / cm 3.
³ or more, the content of ethylene units is 20 mol% or less, _Tm is 100 ° C. or more, and MFR is 0.1 to 0.1.
It is particularly preferable to use polypropylene and / or a copolymer of propylene and ethylene having a melting point of 140 to 170 ° C. and 100 g / 10 minutes.

As the olefin resin, an amorphous olefin resin can be used in addition to the above crystalline olefin resin. Examples of the amorphous olefin resin include homopolymers such as atactic polypropylene and atactic poly-1-butene, propylene (containing 50 mol% or more) and other α-olefins (ethylene, 1-butene, 1-pentene). , 1-hexene, 4-methyl-1-pentene, 1-octene, 1-decene, etc.), 1-butene (5
0 mol% or more) and other α-olefins (ethylene,
Propylene, 1-pentene, 1-hexene, 4-methyl-1-pentene, 1-octene, 1-decene, etc.) and the like.

Amorphous olefin resin at 190 ° C.
Melt viscosity is 50,000 cSt or less, preferably 100 to
30,000 cSt, more preferably 200 to 20,000
It is cSt. Furthermore, the crystallinity measured by X-ray diffraction is
Less than 50%, preferably 30% or less, more preferably 2
It is 0% or less. Density is 0.85-0.89g / c
m ^Three, And more preferably 0.85-0.88 g / cm^Threeso
Preferably there is. Furthermore, the number of amorphous olefin resins
Average molecular weight M_nIs 1000 to 20000 (more preferably
Is preferably 1500 to 15000). Communication
Usually, amorphous olefin resin is combined with crystalline olefin resin.
Used in combination, but either one may be used
Yes.

The proportion of the component (B) in the thermoplastic elastomer composition is 5 to 50% by weight, preferably 10 to 45, when the total amount of (A) and (B) is 100% by weight.
%, More preferably 15-40% by weight. 5
If it is less than 10% by weight, the phase structure (morphology) of the finally obtained thermoplastic elastomer composition does not become a good sea-island structure, which is a characteristic of the dynamically crosslinked thermoplastic elastomer, and the moldability and mechanical properties deteriorate. Fear, 50
If it exceeds 5% by weight, the flexibility and rubber elasticity of the finally obtained thermoplastic elastomer are deteriorated, which is not preferable.

Softening Agent and / or Plasticizer The thermoplastic elastomer composition of the present invention may further contain a softening agent and / or a plasticizer, if necessary, in addition to the above-mentioned components (A) and (B). it can. Examples of the softening agent used in the present invention include aromatic oils, naphthenic oils, paraffin oils, white oils, petroleum-based softening agents such as gilsonite, castor oil, cottonseed oil, rapeseed oil, palm oil, coconut oil, and vegetable oils such as rosin. A softening agent may be used. Further, as the plasticizer used in the present invention, dimethyl phthalate, diethyl phthalate, dibutyl phthalate, diisobutyl phthalate, dioctyl phthalate,
Butyl octyl phthalate, di- (2-ethylhexyl) phthalate, diisooctyl phthalate, diisodecyl phthalate and other phthalates, dimethyl adipate, diisobutyl adipate, di- (2-ethylhexyl) adipate, diisooctyl adipate, diisodecyl adipate, Octyldecyl adipate, di-
Fatty acid esters such as (2-ethylhexyl) azelate, diisooctyl azelate, diisobutyl azelate, dibutyl sebacate, di- (2-ethylhexyl) sebacate, diisooctyl sebacate, trimellitic acid isodecyl ester, trimellitate In addition to trimellitic acid esters such as acid octyl ester, trimellitic acid n-octyl ester and trimellitic acid isononyl ester, di- (2-ethylhexyl) fumarate, diethylene glycol monooleate, glyceryl monoricinolate, trilauryl phosphate Plasticizers such as tristearyl phosphate, tri- (2-ethylhexyl) phosphate, tricresyl phosphate, epoxidized soybean oil, and polyether ester. In carrying out the present invention, the above-mentioned softening agent and / or plasticizer can be used alone or in combination of two or more kinds. Further, the softening agent and / or the plasticizer may be added to the component (A) and the component (B) during the production of the thermoplastic elastomer composition, or may be added during the polymerization of the component (A).

The amount of the above-mentioned softening agent and / or plasticizer may be 100 parts by weight or less, preferably 9 parts by weight, per 100 parts by weight of the total amount of the components (A) and (B).
It can be 5 parts by weight or less, more preferably 90 parts by weight or less. If it exceeds 100 parts by weight, the softening agent tends to bleed out from the finally obtained thermoplastic elastomer composition, or the mechanical strength and the rubber elasticity tend to decrease.

Other Polymers The thermoplastic elastomer composition of the present invention may further contain other polymers in addition to the above components (A) and (B), if necessary. Other polymers used in the present invention include ethylene / α-olefin random copolymer rubber, butyl rubber, acrylic rubber, halogenated polyolefin rubber, cis-1,4-polybutadiene, cis-
1,4-polyisoprene, 1,2-polybutadiene, styrene-butadiene random copolymer, styrene-butadiene block copolymer, styrene-isoprene block copolymer, hydrogenated diene polymer, (meth) acrylate resin, etc. Is mentioned.

Cross-linking Agent The cross-linking agent used in the present invention is a compound capable of cross-linking at least one unsaturated nitrile-conjugated diene rubber in the composition by dynamic heat treatment at a temperature above the melting point of the olefin resin. Is. Examples of such a crosslinking agent include organic peroxides, phenolic crosslinking agents, sulfur, sulfur compounds, p-quinone, p-quinonedioxime derivatives, bismaleimide compounds, epoxy compounds, silane compounds,
Examples thereof include amino resins, and organic peroxides and phenolic crosslinking agents are particularly preferable. Examples of the organic peroxide include 1,3-bis (t-butylperoxyisopropyl) benzene and 2,5-dimethyl-2,5-
Bis (t-butylperoxy) hexyne-3,2,5-
Dimethyl-2,5-bis (t-butylperoxy) hexene-3,2,5-dimethyl-2,5-bis (t-butylperoxy) hexane, 2,2'-bis (t-butylperoxy) ) -P-Isopropylbenzene, dicumyl peroxide, di-t-butyl peroxide, t-butyl peroxide, p-menthane peroxide, 1,1-bis (t-butylperoxy) -3,3,5 -Trimethylcyclohexane, dilauroyl peroxide, diacetyl peroxide, t-butyl peroxybenzoate,
2,4-dichlorobenzoyl peroxide, p-chlorobenzoyl peroxide, benzoyl peroxide, di (t-butylperoxy) perbenzoate, n-butyl-4,4-bis (t-butylperoxy) valerate, t -Butyl peroxy isopropyl carbonate etc. can be mentioned. Of these organic peroxides,
1,3-bis (t-butylperoxyisopropyl) benzene, 2,5-dimethyl-2,5-di (t-butylperoxy) hexyne-3,2,5-dimethyl-2,5-
A compound having a relatively high decomposition temperature such as di (t-butylperoxy) hexane is preferable.

The above organic peroxides can be used alone or in admixture of two or more. In the present invention, a uniform and gentle crosslinking reaction can be carried out by using the organic peroxide in combination with a suitable crosslinking aid. Examples of such a cross-linking aid include powdered sulfur, colloidal sulfur, precipitated sulfur, insoluble sulfur, surface-treated sulfur, sulfur such as dipentamethylene thiuram tetrasulfide, or sulfur compounds; p-quinone oxime, p, p′-diamine. Oxime compounds such as benzoylquinone oxime; ethylene glycol di (meth) acrylate, diethylene glycol di (meth) acrylate, triethylene glycol di (meth) acrylate, tetraethylene glycol di (meth) acrylate, polyethylene glycol di (meth) acrylate, tri Methylolpropane tri (meth) acrylate, diallyl phthalate, tetraallyloxyethane, triallyl cyanurate, N, N'-m
Examples thereof include polyfunctional monomers such as phenylene bismaleimide, N, N′-toluylene bismaleimide, maleic anhydride, divinylbenzene and zinc di (meth) acrylate. Among these crosslinking aids, p, p '
-Dibenzoylquinone oxime, N, N'-m-phenylene bismaleimide, divinylbenzene are preferred. In addition, N, N'-m-phenylene bismaleimide can act as a cross-linking agent alone. The cross-linking aids can be used alone or in admixture of two or more.

As the above-mentioned phenolic crosslinking agent, a condensate of p-substituted phenol and an aldehyde (preferably formaldehyde) in the presence of an alkali catalyst, o-
Examples thereof include a condensate of a substituted phenol and an aldehyde, a condensate of an m-substituted phenol and an aldehyde, a condensate of a brominated alkylphenol and an aldehyde, and the like.
Of these, p-substituted phenol compounds are preferable. This p
-Substituted phenolic compounds are described in U.S. Pat. No. 328744.
As described in No. 0 and US Pat. No. 3,709,840, it has been conventionally used as a crosslinking agent for rubber.

The above-mentioned phenolic crosslinking agent can be used alone, but it can also be used in combination with a crosslinking accelerator in order to control the crosslinking rate. Examples of such a crosslinking accelerator include metal halides such as stannous chloride and ferric chloride; organic halides such as chlorinated polypropylene, butyl bromide rubber, and chloroprene rubber. Further, it is more desirable to use a metal oxide such as zinc oxide and a dispersant such as stearic acid together.

When an organic peroxide is used as the crosslinking agent, the amount thereof is preferably 0.05 to 10 parts by weight, based on 100 parts by weight of the mixture of the components (A) and (B). It can be preferably 0.1 to 5 parts by weight. If the amount of the organic peroxide used is less than 0.05 parts by weight, the degree of crosslinking may be insufficient and the rubber elasticity and mechanical strength of the finally obtained thermoplastic elastomer composition may be reduced. On the other hand, if the amount exceeds 10 parts by weight, the degree of crosslinking becomes excessively high, which tends to deteriorate the moldability and mechanical properties. When an organic peroxide is used as the cross-linking agent, the amount of the cross-linking aid used is preferably 1 with respect to 100 parts by weight of the mixture of the components (A) and (B).
The amount can be 0 part by weight or less, more preferably 0.2 to 5 parts by weight. When the amount of the cross-linking aid used exceeds 10 parts by weight, the degree of cross-linking becomes excessively high, which tends to deteriorate the moldability and mechanical properties.

When a phenolic cross-linking agent is used as the cross-linking agent, the mixture 100 of the above components (A) and (B) is used.
The amount can be preferably 0.2 to 10 parts by weight, more preferably 0.5 to 5 parts by weight with respect to parts by weight. If the amount of the phenol-based cross-linking agent used is less than 0.2 parts by weight, the elastic recovery of the molded product tends to decrease. On the other hand, if it exceeds 10 parts by weight, the extrusion processability and the injection processability of the thermoplastic elastomer composition tend to decrease.

Method for Producing Thermoplastic Elastomer Composition The thermoplastic elastomer composition of the present invention may be obtained by any method. For example, a predetermined amount of the component (A),
A thermoplastic elastomer composition having excellent properties by adding a cross-linking agent, a cross-linking aid and the like to a mixture containing the component (B) (first step) and performing dynamic heat treatment (second step) Can be obtained. It can also be obtained by dynamically heat-treating a mixture containing a predetermined amount of component (A), component (B), and a crosslinking agent. When the component (A) produced by mixing two types of unsaturated nitrile-conjugated diene rubbers having different Tg is used,
A mixture of the above (a) and (b) components and (B)
The components may be mixed, or the component (a), the component (b) and the component (B) may be mixed at the same time.

The "dynamic heat treatment" means to apply both shearing force and heating. This dynamic heat treatment can be performed using, for example, a melt-kneading device. Among these, as an apparatus capable of kneading, for example, an open type mixing roll, a non-open type Banbury mixer, a kneader, a continuous extruder; a single-screw extruder, a co-rotating continuous twin-screw extruder, a different extruder A device such as a direction rotation type continuous twin-screw kneader can be used. Further, the treatment performed by this kneading device may be a batch type or a continuous type.

The processing conditions of the dynamic heat treatment in the present invention are as follows:
The processing temperature is 120 to 350 ° C, depending on the melting point of the olefin resin used, the type of crosslinking agent, the kneading type, etc.
(More preferably 150 to 290 ° C.), and the treatment time is 20 seconds to 20 minutes (more preferably 30).
Seconds to 15 minutes). The shearing force applied is
The shear rate is 10 to 2000 / sec (more preferably 100
It is preferable to be set to 1000 / second).

In the thermoplastic elastomer composition of the present invention, if necessary, various additives such as a lubricant, an antioxidant, a heat stabilizer, a weather resistance agent, a metal deactivator, an ultraviolet absorber,
Light stabilizers, stabilizers such as copper damage inhibitors, antibacterial and antifungal agents,
Dispersant, plasticizer, crystal nucleating agent, flame retardant, tackifier, foaming aid, titanium oxide, colorant such as carbon black, metal powder such as ferrite, glass fiber, inorganic fiber such as metal fiber, carbon fiber, Organic fibers such as aramid fibers, composite fibers, inorganic whiskers such as potassium titanate whiskers, glass beads, glass balloons, glass flakes, asbestos, mica, calcium carbonate, talc, silica, calcium silicate, hydrotalcite, kaolin, silica Filler such as algae earth, graphite, pumice, evo powder, cotton floc, cork powder, barium sulfate, fluororesin, polymer beads, etc. or a mixture thereof, filler such as polyolefin wax, cellulose powder, rubber powder, wood powder, low A molecular weight polymer or the like can be blended and used.

The thermoplastic elastomer composition of the present invention comprises
Injection molding, extrusion molding, hollow molding, compression molding, vacuum molding,
Processing by lamination molding, calendar molding, etc. becomes easy,
It is possible to obtain a thermoplastic elastomer molded article having excellent rubber elasticity and mechanical properties.

The thermoplastic elastomer composition of the present invention comprises
Hoses such as oil hoses, fuel hoses, gas hoses, brake hoses, covers for these hoses, packing, gaskets, O-rings, belts, linings, oil seals, making use of their excellent oil resistance, flexibility and molding processability. It is preferably used for manufacturing industrial parts such as dust boots, parts for aircraft and automobiles. Also, interior and exterior skins such as automobile bumpers, exterior moldings, wind seal gaskets, door seal gaskets, trunk seal gaskets, roof side rails, emblems, inner panels, console boxes, etc. that use conventional thermoplastic elastomers. Materials, weather strips, leather sheets, sealing materials for aircraft and ships, and interior / exterior skin materials, etc.
Sealing materials for civil engineering / construction, interior / exterior skin materials, waterproof sheets, etc., sealing materials for general machinery / equipment, packing for light electrical parts or housings, medical equipment parts, electric wires, daily sundries, sports equipment It can also be widely used for general processed products such as.

[0046]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described with reference to Examples, but the present invention is not limited thereto. Preparation of Thermoplastic Elastomer Composition Unsaturated Nitrile-Conjugated Diene Rubber, Olefin Resin, Plasticizer,
The two types of dynamic heat treatment methods shown below were applied to the crosslinking agent and other additives in the proportions shown in Table 1 to obtain a thermoplastic elastomer composition.

(1) Unsaturated nitrile-conjugated diene rubber An unsaturated nitrile-conjugated diene rubber was synthesized by the method described below. Various measurements were based on the following methods. Unsaturated nitrile (AN) content: determined by Coleman nitrogen analyzer. MEK insoluble matter (%): About 0.2 g of polymer crumb was placed in a 200-mesh stainless wire mesh box of known weight, the box was immersed in a beaker containing 80 ml of methyl ethyl ketone, and the lid was covered with aluminum foil. After standing and soaking for 24 hours, the box was taken out and decompressed at 40 ° C (750 mmH
g) Dry under 4 hours. The weight of the sample before and after the immersion was measured, and the MEK insoluble content (%) was determined by the following formula. MEK insoluble matter (% by weight) = (W ′ / W) × 100 (W: weight of sample taken, W ′: weight after immersion) Glass transition temperature (Tg): DSC2910 manufactured by TA Instruments. Was used to measure the glass transition temperature by increasing the temperature from −100 ° C. to 100 ° C. at a temperature increase rate of 10 ° C./min. Mooney viscosity (ML _{1 + 4} , 100 ° C): The Mooney viscosity of the component (A) is an automatic Mooney viscometer SMV.
-201 (manufactured by Shimadzu Corporation) using JIS K630
The Mooney viscosity was measured under the temperature condition of 100 ° C.

Synthesis of unsaturated nitrile-conjugated diene rubber In an autoclave having an internal capacity of 20 liters, 250 parts by weight of water, 5 parts by weight of sodium dodecylbenzenesulfonate, 66 parts by weight of butadiene (hereinafter abbreviated as BD), acrylonitrile (hereinafter 34 parts by weight of AN) and 0.5 parts by weight of t-dodecyl mercaptan (hereinafter abbreviated as TDM), 0.27 parts by weight of potassium persulfate, 0.15 parts by weight of cyanoethylated diethanolamine, and potassium hydroxide of 0.
10 parts by weight were charged and polymerization was started at 20 ° C. After the polymerization rate reached 80%, 0.2 part by weight of diethylhydroxylamine was added to 100 parts by weight of the monomer to terminate the polymerization. Then, after heating and removing residual monomers by steam distillation, 1 part by weight of alkylated phenol as an anti-aging agent was added per 100 parts by weight of rubber solid content, and coagulated with an aqueous calcium chloride solution. The obtained crumbs were washed with water and then vacuum dried at 50 ° C. to synthesize NBR1. The obtained NBR1 has an AN content of 34% by weight and MEK
Insoluble matter is 0%, Tg is -29 ° C, Mooney viscosity (ML
_{1 + 4} , 100 ° C.) was 72. NBR2 to NBR3 shown in Table 1 were obtained by changing the charged amount of the monomer according to NBR1.

[0049]

[Table 1]

(2) Olefin resin Olefin resin 1: polypropylene polymer, density 0.9
0 g / cm ³ , MFR (temperature 230 ° C, load 2.16k
g) 3 g / 10 min, manufactured by Nippon Polychem, product name “Novatech PP MA4” (3) Additive plasticizer 1: dibutyl carbitol adipate, manufactured by Asahi Denka Kogyo, product name “RS-107” Plasticizer 2: trimellitic acid Ester, manufactured by Asahi Denka Co., Ltd., product name "CN-79" Crosslinking agent 1: 2,5-dimethyl-2,5-di (t-butylperoxy) hexane, manufactured by NOF Corporation, product name "Perhexa 25B-40" Crosslinking agent 2: divinylbenzene (purity 56%), Sankyo Kasei's anti-aging agent: pentaerythrityl-tetrakis [3-
(3,5-di-tert-butyl-4-hydroxyphenyl) propionate]

Example 1 (A) As an unsaturated nitrile-conjugated diene rubber (NBR
1) 64 parts, (NBR3) 7 parts, (B) olefin resin (olefin resin 1) 29 parts, plasticizer (plasticizer 1) 43 parts, antioxidant 0.3 parts were heated to 150 ° C. The mixture was put into a 10-liter dual-arm pressure kneader (manufactured by Moriyama Co., Ltd.) and kneaded at 40 rpm for 20 minutes. Then, the molten composition was pelletized with a feeder ruder (manufactured by Moriyama Co., Ltd.) set at 180 ° C. and 40 rpm.
Further, 1.4 parts of (crosslinking agent 1) as a crosslinking agent and 2 parts of (crosslinking agent 2) as a crosslinking aid were blended in the obtained pellets, mixed for 30 seconds with a Henschel mixer, and a twin-screw extruder ( Ikegai Co., Ltd., model “PCM-45”, same direction complete meshing type screw, screw flight length L
L / D, which is the ratio of the screw diameter D to the screw diameter D) is 38.5), and is extruded while being subjected to dynamic heat treatment under the condition of staying at 230 ° C. and 300 rpm for 2 minutes to form a pellet-like dynamic cross-link. A type thermoplastic elastomer composition was obtained.

Preparation of Thermoplastic Elastomer Test Pieces The obtained thermoplastic elastomer pellets were injection-molded using an injection molding machine (trade name N-100, manufactured by Nippon Steel Co., Ltd.) to obtain a thickness of 2 mm, a length of 120 mm and a width. A 120 mm sheet was prepared and subjected to various evaluations.

Evaluation of Thermoplastic Elastomer The fluidity of the obtained thermoplastic elastomer was measured as the melt flow rate at 230 ° C. under a load of 10 kg, and is shown in Table 2. Further, using the molded sheet of the thermoplastic elastomer obtained, hardness, mechanical properties (tensile rupture strength,
Tensile elongation at break), rubber elasticity and oil resistance were evaluated by the following methods, and are shown in Table 2. Hardness: Measured according to JIS-K6253 as an index of flexibility. Tensile breaking strength and tensile breaking elongation: JIS-K6251
It was measured according to. Compression set: JIS-K62 as an index of rubber elasticity
According to 62, the measurement conditions were 70 ° C. and 22 hours. Oil resistance: conforming to JIS-K6258, IRM903
Using the test oil and Fuel C test oil, the volume change rate (ΔV) was measured by a dipping test at 120 ° C. for 70 hours.

Evaluation of Molding Processability of Thermoplastic Elastomer Composition Labo Plast Mill Extruder (Outer Diameter = 20
mm, L / D (ratio of effective screw length L and outer diameter D) =
25), and flat plate extrusion (base width 25
mm, thickness 1.5 mm), and the appearance was visually evaluated. Those with a smooth surface and edges were marked with ⊚ or ◯ (however, ◎> ○), and otherwise were marked with x. Cylinder C1 = 190 ° C. Cylinder C2 = 190 ° C. Cylinder C3 = 200 ° C. Die = 190 ° C. Screw rotation speed = 30 rpm

Examples 2 to 3 and Comparative Examples 1 to 3 At the compounding ratios shown in Table 2, in the same manner as in Example 1, pelletized crosslinked thermoplastic elastomer compositions and test pieces were obtained. Table 2 shows the evaluation results of the obtained thermoplastic elastomer composition.

[0056]

[Table 2]

Table 2 shows that Examples 1 to 3 are excellent in oil resistance, mechanical properties, rubber elasticity (low compression set), and moldability. The unsaturated nitrile-conjugated diene rubber of Comparative Example 1 has only one glass transition temperature, which is a feature of the present invention, and is inferior in mechanical properties, rubber elasticity, and moldability. The unsaturated nitrile-conjugated diene rubber of Comparative Example 2 has an unsaturated nitrile content of 17% by weight, which is out of the range of the present invention and thus is inferior in oil resistance. Further, Comparative Example 3 is inferior in mechanical properties and rubber elasticity because it is not dynamically crosslinked.

[0058]

EFFECTS OF THE INVENTION The thermoplastic elastomer composition of the present invention is excellent in oil resistance, has a low compression set, and is excellent in molding processability. Therefore, oil hose, fuel hose, gas hose, brake hose, etc. Hose, covers for these hoses, packing, gaskets, O-rings, belts, linings, oil seals, industrial parts such as oil boots, dust boots and the like, and are preferably used for manufacturing parts for aircraft and automobiles. In addition, it is also suitable for use in interior / exterior parts such as automobile weather strips, sponges, and moldings in which conventional olefinic thermoplastic elastomers are used, molded parts such as housings for light electrical parts, and leather sheet products. You can

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Akihiko Morikawa             2-11-21 Tsukiji, Chuo-ku, Tokyo J             Within SRL Co., Ltd. F-term (reference) 4F070 AA07 AA12 AC32 AC37 AC43                       AC56 AC63 AC65 AE02 AE03                       AE08 GA05 GA06 GB07 GB08                 4F071 AA12X AA14 AA15 AA15X                       AA20X AA21X AA28X AA33X                       AA34X AA75 AA76 AB04                       AC02 AC07 AC08 AC11 AC12                       AC16 AE02 AH07 AH12 AH19                       BA01 BB05                 4J002 AC071 BB032 BB052 BB062                       BB072 BB122 BB142 BB172                       BC023 DA047 EH077 EK016                       EK036 EK046 EK056 EK066                       EK086 ES017 EU027 EV047                       FD146 FD153 FD157 GJ02                       GM00 GN00 GQ00

Claims (6)

[Claims] 1. (A) having two or more glass transition temperatures,
It is obtained by dynamically heat-treating a mixture containing an unsaturated nitrile-conjugated diene rubber having an unsaturated nitrile unit content of 25 to 50% by weight and (B) an olefin resin in the presence of a crosslinking agent. A thermoplastic elastomer composition comprising: 2. The unsaturated nitrile-conjugated diene rubber (A) 50 to 95% by weight and the olefin resin (B) 50 to 50% by weight.
5% by weight (however, the total amount of (A) and (B) is 100)
% By weight). 3. The unsaturated nitrile-conjugated diene rubber (A) has an unsaturated nitrile unit content of 30 to 70% by weight.
And an unsaturated nitrile-conjugated diene rubber (b) having an unsaturated nitrile unit content of 5 to 25% by weight. The thermoplastic elastomer composition according to 1 or 2. 4. The ratio of the unsaturated nitrile-conjugated diene rubber (a) to the unsaturated nitrile-conjugated diene rubber (b) is a weight ratio ((a) / (b)) of 1.5 to. 20. The thermoplastic elastomer composition according to claim 3, wherein the thermoplastic elastomer composition is 20. 5. The unsaturated nitrile-conjugated diene rubber (A) has a methyl ethyl ketone insoluble content of 1 at 23 ° C.
It is 0-99%, The thermoplastic elastomer composition of Claims 1-4 characterized by the above-mentioned. 6. A molded article containing the thermoplastic elastomer composition according to any one of claims 1 to 5.