WO2005042624A1

WO2005042624A1 - Thermoplastic elastomer composition and formed article

Info

Publication number: WO2005042624A1
Application number: PCT/JP2004/016106
Authority: WO
Inventors: Kiyonori Umetsu; Hirofumi Masuda; Kazuhiro Ejiri
Original assignee: Zeon Corporation
Priority date: 2003-10-31
Filing date: 2004-10-29
Publication date: 2005-05-12
Also published as: JPWO2005042624A1

Abstract

A thermoplastic elastomer composition which is prepared by subjecting 20 to 95 wt % of at least one resin (A) of a polyamide resin (A1) and a polyester resin (A2), which has a melting point of 160 to 300˚C and a bending elastic modulas at 23˚C of 10,000 kgf/cm2 or less, and 5 to 80 wt % of at least one rubber (B) selected from the group consisting of an acrylic rubber (B1), a nitrile rubber (B2), a hydrogenated nitrile rubber (B3) and an epihalohydrin rubber (B4) to dynamic crosslinking while kneading them. The thermoplastic elastomer composition can provide a formed article which exhibits excellent heat resistance, a reduced compression set and excellent fatigue resistance.

Description

Specification

Thermoplastic elastomer compositions and molded articles

Technical field

[0001] The present invention relates to a thermoplastic elastomer composition comprising a polyamide resin and / or a polyester resin and a specific rubber. More specifically, the present invention has excellent heat resistance, and further has improved compression set and fatigue resistance. A thermoplastic elastomer composition.

Background art

[0002] Polyamide-based elastomers and polyester-based elastomers, which are block copolymers obtained by combining a polyamide or polyester block with a polyether block, have excellent mechanical properties and appropriate flexibility. It is a thermoplastic elastomer having. However, these elastomers have a high hardness and are inferior in heat resistance and compression set for use as rubber-like elastic materials. Therefore, as a method of improving these characteristics, a method of mixing rubber with the above-mentioned elastomer has been attempted, and various rubber blending techniques have been proposed.

[0003] In recent years, it has been proposed to finely disperse crosslinked rubber particles in the elastomer matrix in order to improve elongation and compression set.

[0004] For example, Patent Document 1 proposes a thermoplastic elastomer composition obtained by dispersing and mixing a crosslinked rubber component containing at least 20% of a gel component in a polyester elastomer component. Specifically, this document discloses a composition in which a crosslinked carboxy-modified nitrile-butadiene rubber is kneaded with a polyester ester elastomer using a brabender.

. However, simply dispersing and mixing the crosslinked rubber component in the elastomer does not sufficiently improve the compression set.

On the other hand, Patent Document 2 discloses a crosslinking agent comprising a polyamide-based elastomer or a polyester-based elastomer, and a rubber particle having a core Cielny layer structure comprising a core layer of a crosslinking rubber and a shell layer of a rubber having a crosslinking group. A method has been proposed in which the rubber particles are dispersed in an elastomer while kneading in the presence of a rubber layer while mainly crosslinking the shell layer. However, while this method improves tensile properties and compression set, it has the problem of inferior heat resistance. is there.

[0006] Patent Document 3 discloses a powerful thermoplastic elastomer composition comprising a rubber of acrylate rubber, ethylene-atarylate rubber or a combination thereof, polyester, polycarbonate or polyphenylene oxide, or a combination thereof, and a strong thermoplastic elastomer composition. ing. In particular, this document discloses a thermoplastic elastomer composition using a rubber which is at least partially cross-linked with a cross-linking agent of a polyfunctional oxazoline, oxazine, imidazoline, carbodiimide or a combination thereof as the rubber. ing. However, molded articles of the composition described in this document have a problem that compression permanent set is insufficiently improved and fatigue resistance is poor.

Patent Document 1: JP-A-5-79256

Patent Document 2: JP-A-8-231770

Patent Document 3: Japanese Patent Application Laid-Open No. 11-246749

Disclosure of the invention

Problems to be solved by the invention

[0007] An object of the present invention is to provide a thermoplastic elastomer composition which can provide a molded article having excellent heat resistance, small compression set, and excellent fatigue resistance. Means for solving the problem

[0008] The inventors of the present invention have conducted intensive studies to solve the above problems, and as a result, kneaded a polyamide resin or a polyester resin having a melting point in a specific range and a flexural modulus not more than a specific value with a specific rubber. The inventors have found that a thermoplastic elastomer composition dynamically crosslinked while achieving the above object achieves the above object, and has completed the present invention based on this finding.

According to the present invention, the following inventions 115 are provided.

1. At least one kind of polyamide resin (A1) or polyester resin (A2) having a flexural modulus of 10,000 kgf / cm ² or less at a melting point of 160-300 ° C and a temperature of 23 ° C. 95% by weight,

Acrylic rubber (B1), nitrile rubber (B2), a hydrogenated nitrile rubber (B3) and at least one rubber selected from the group consisting of Epiharohidorin rubber (B4) (B) 5- 80 wt ^_0/0,

A thermoplastic elastomer composition obtained by dynamically crosslinking while kneading. 2. The resin (A) contains a plasticizer,

2. The thermoplastic elastomer composition according to claim 1, wherein the content of the plasticizer is 1 to 50 parts by weight per 100 parts by weight of the resin (A).

3. The rubber (B) contains a gel component,

3. The thermoplastic elastomer composition according to the above 1 or 2, wherein the content of the gel component is 30 to 100% by weight based on 100% by weight of the whole rubber (B).

4. The thermoplastic elastomer composition according to any one of items 13 to 13, wherein the particles of the rubber (B) are finely dispersed in a matrix of the resin (A).

5. A molded article obtained by molding the thermoplastic elastomer composition according to any one of the above items 1 to 4 at 160 to 350 ° C.

The invention's effect

According to the present invention, there is provided a thermoplastic elastomer composition in which crosslinked rubber particles are finely dispersed in a matrix of a polyamide resin or a polyester resin. Since this thermoplastic elastomer composition can provide molded articles having low compression set and excellent fatigue resistance in addition to heat resistance, various rubber parts such as seals, hoses, automobile boots and the like can be provided. It can be suitably used as a product.

BEST MODE FOR CARRYING OUT THE INVENTION

[0011] The thermoplastic elastomer composition of the present invention has a polyamide resin having a melting point of 160 to 300 ° C and a flexural modulus at a temperature of 23 ° C of 10,000 kgf / cm ² (23 ° C) or less. (A1) or at least one resin (a) 20- 95 wt ^_0/0 of the poly ester resin (A2), and at least one rubber (B) 80- 5% by weight selected from an acrylic rubber (B1) group, Is dynamically kneaded while kneading.

[0012] Fat (A)

The resin (A) of the present invention is a polyamide resin (A1) or a polyester resin (A2), or a mixture of these resins.

[0013] Polyamide resin (A1)

The polyamide resin (A1) used in the present invention is a polymer having an acid amide bond (-CONH-). It is.

Examples of such a polymer include a polymer obtained by polycondensation of diamine and a dibasic acid, a polymer obtained by polycondensation of a diamine derivative such as diformyl and a dibasic acid, and a dibasic polymer such as dimethyl ester. A polymer obtained by the polycondensation of an acid derivative with diamine, a polymer obtained by the reaction of dinitrile or diamide with formaldehyde, a polymer obtained by polyaddition of diisocyanate with a dibasic acid, a self-product of an amino acid or its derivative Examples thereof include a polymer obtained by condensation, a polymer obtained by ring-opening polymerization of ratatum, and the like. Further, these polyamide resins may contain a polyether block.

[0014] Specific examples of these polyamide resins include polycapramide (6-nylon), polyhexamethylene adipamide (66-nylon), polyhexamethylene sebacamide (610-nylon), and polyundecaneamide. (11-nylon), polylaurinamide (12-nylon), poly-ω-aminoheptanic acid (7-nylon), poly-ω_aminononanoic acid (9-nylon) and the like. Among these, 6-nylon, 66-nylon, 12-nylon and 11_nylon are preferred from the viewpoints of versatility and heat resistance.

[0015] The polymerization degree of the polyamide resin (A1) used in the present invention is usually 90-600, preferably 100-500.

[0016] Polyester resin (Α2)

The polyester resin (# 2) used in the present invention is a polymer having an ester bond, and is usually obtained by polycondensation of a polyhydric alcohol and a polybasic acid or a polybasic acid ester compound.

[0017] In the present invention, as the polyester resin (# 2), for example, generally known polyester resins such as an alkyd resin, a maleic acid resin, a saturated polyester resin, and an unsaturated polyester resin can be used.

As the polyhydric alcohol, ethylene glycol, diethylene glycol, triethylene glycol, butylene glycol, trimethylene glycol, propylene glycol, cyclohexane dimethanol, and the like are used. As the polybasic acid, phthalic acid, fumaric acid, adipic acid and the like are used.

[0019] Among these, from the viewpoints of heat resistance, mechanical strength, and the like, polyhydric alcohols include Preference is given to using Tylendalcol, butylene glycol or trimethylene glycol. Further, as the polybasic acid, aromatic polyester resins such as polyethylene terephthalate, polybutylene terephthalate, and polytrimethylene terephthalate obtained by using phthalic acid are particularly preferable.

In the present invention, it is preferable that the polyester resin does not have a polyether block as a copolymer component. When a polyester resin having a polyether block is used, heat resistance may be reduced.

[0021] The weight average molecular weight of the polyester resin (A2) used in the present invention is usually 40,000-100,000, and preferably <60,000-100,000.

[0022] The polyamide resin (A1) and the polyester resin (A2) used in the present invention have a melting point of 160-300. C, preferably 165-270. C, more preferably 170-220. C's. If the melting point is too low, the heat resistance of the thermoplastic elastomer obtained is inferior, and if it is too high, the polyamide resin (A1) and the polyester resin (A2) may deteriorate during processing. The melting points of the polyamide resin (A1) and the polyester resin (A2) can be determined from the peak temperature of the heat of fusion using a differential scanning calorimeter.

[0023] Polyamide resins for use in the present invention (A1) and polyester resin (A2), the elastic modulus force 10 Contact Keru bending temperature 23 ° C, and at 000kgf / cm ² or less, preferably 8, 000kgf / cm ² or more Lower, more preferably 7, OOOkgfZcm ² or less. The lower limit of the flexural modulus is not particularly limited, but is usually about 2, OOOkgfZcm ² . If the flexural modulus is too large, the compression set is inferior.

In the present invention, a polyamide resin composition containing a plasticizer and a polyester resin composition containing a plasticizer are used as the polyamide resin (A1) and the polyester resin (A2) having a flexural modulus within the above range. It is preferable to use

[0025] Examples of the plasticizer include di- (2-ethylhexyl) phthalate, di-n-octyl phthalate, diisonol phthalate, dicyclohexyl phthalate, diphenyl phthalate, benzyl phthalate, and benzyl phthalate. -Hydroxyethynole Phthalate compounds such as 2-ethylhexyl; Phosphate compounds such as triphenyl phosphate, tricresinole phosphate, decyldiphenyl phosphate, and triethyl phosphate; Kishiru), Trimerit Trimellitic acid ester compounds such as acid tree n-octyl; adipic acid ester compounds such as di- (2-ethylhexyl) adipate, dibutoxetinole adipate and diisononinole adipate; Azelaic acid ester compounds such as xyl and diazelleate (2-ethylhexyl); sulfonamide derivatives such as butylbenzenesulfonamide; sebacic acid ester compounds such as di- (2-ethylhexyl) sebacate; n-octinole Hydroxybenzoates such as 1-4-hydroxybenzoate and n-butynole-hydroxybenzoate; and the like.

Of these, phthalic acid ester compounds, sulfonamide derivatives, and hydroxybenzoate are preferred, and phthalic acid-hydroxyethyl-2-ethylhexyl, butylbenzensulfonamide, and n-octyl-4-hydroxybenzoate are more preferred.

[0026] The content of the plasticizer is usually 1 to 50 parts by weight, preferably 5 to 30 parts by weight per 100 parts by weight of at least one resin (A) of the polyamide resin (A1) or the polyester resin (A2). It is. If the content of the plasticizer is too small, the flexural modulus of the resin (A) tends to be too large, and if it is too large, the heat resistance may be deteriorated.

[0027] To blend the plasticizer into the resin (A), the resin (A) and the plasticizer are uniformly mixed at 160-350 ° C using a blender such as a brabender, a twin-screw extruder, or a kneader. Mix well until you get it. If the plasticizer is added at the stage of kneading the resin (A) and the rubber (B), the plasticizer is distributed to both the resin (A) and the rubber (B), so that the resin (A) The flexural modulus is not sufficiently reduced, and the effects of the thermoplastic elastomer composition of the present invention, particularly the improvement effects such as fatigue resistance, are not effectively exhibited, which is not preferable.

[0028] Rubber (B)

The rubber (B) used in the present invention consists of at least one selected from the group consisting of acrylic rubber (B1), nitrile rubber (B2), hydrogenated nitrile rubber (B3) and ephalohydrin rubber (B4). Things. Preferably, the rubber (B) of the present invention is at least one of acrylic rubber (B1) and hydrogenated nitrile rubber (B3).

In the present invention, the rubber (B) needs to have a crosslinkable group suitable for dynamic crosslinking described below. The crosslinkable group may be any crosslinkable group generally known to be capable of reacting with a crosslinker used in rubber processing, and may be appropriately selected depending on the type of the crosslinker used. It may be selected, but it is preferably at least one selected from the group consisting of a halogen-containing group, an epoxy group and a carboxy group.

[0030] The rubber (B) has a viscosity ML (100.C) of preferably 10-150, more preferably

1+ 4

20 to 120, particularly preferably 30 to 100. If the Mooney viscosity is too low, the compression set may increase, and if it is too high, the moldability may be poor.

[0031] As the rubber (B), those containing a gel (also called a gel component) can be preferably used. The gel content of the rubber (B), to the rubber (B) total 100 weight ^_0/0, preferably 30- 1 00 wt%, more preferably 50 to 100 wt%, particularly preferably 60- 100 wt% It is. When the gel content is in the above range, a thermoplastic elastomer composition having a smaller compression set can be obtained. The gel component is preferably dispersed uniformly in the rubber.

[0032] The gel content of the rubber (B) can be measured by the following method. That is, after dissolving a predetermined amount of rubber (B) with a good solvent for the rubber, the solution is filtered through a filter such as an 80-mesh wire mesh, and the solvent-insoluble matter trapped on the filter is dried to weigh. It is measured and calculated as the weight ratio to the initial predetermined amount.

[0033] Acrylic rubber (B1)

The acrylic rubber (B1) has an acrylate monomer or a methacrylate ester monomer [hereinafter abbreviated as (meth) acrylate monomer] in the molecule. ] Unit. The content of the (meth) acrylate monomer unit is preferably 55 to 99.5% by weight, more preferably 85 to 99% by weight, and particularly preferably 100% by weight of the whole acrylic rubber (B1). Is from 95 to 98% by weight, and the balance has monomer units copolymerizable with the (meth) acrylate monomer.

[0034] Examples of the (meth) acrylic acid ester monomer include (meth) acrylic acid alkyl ester monomers and (meth) acrylic acid alkoxyalkyl ester monomers.

As the (meth) acrylic acid alkyl ester monomer, an ester of alkinol having 118 carbon atoms with (meth) acrylic acid is preferred.

Specifically, methyl (meth) acrylate, ethyl (meth) acrylate, n-propyl (meth) acrylate, n-butyl (meth) acrylate, isopropyl (meth) acrylate, isobutyl (meth) acrylate , N-hexyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, (meth ) Cyclohexyl acrylate and the like.

Among them, ethyl (meth) acrylate and n-butyl (meth) acrylate are preferable, and ethyl acrylate and _n -butyl acrylate are particularly preferable.

[0036] As the (meth) acrylic acid alkoxyalkyl ester monomer, an ester of an alcoholic alcohol having 2 to 8 carbon atoms and (meth) acrylic acid is preferable.

Specifically, methoxymethyl (meth) acrylate, ethoxymethyl (meth) acrylate, 2_ethoxyshethyl (meth) acrylate, 2_butoxyshethyl (meth) acrylate, 2-methoxyethyl (meth) acrylate, ) 2-propoxyshetyl acrylate, 3-methoxypropyl (meth) acrylate, 4-methoxybutyl (meth) acrylate and the like.

Among them, 2-ethoxyethyl (meth) acrylate and 2-methoxyethyl (meth) acrylate are preferable, and 2-ethoxyethyl acrylate and 2-methoxyethyl acrylate are particularly preferable.

[0037] The acrylic rubber (B1) used in the present invention contains a monomer unit copolymerizable with a (meth) acrylate monomer in addition to a (meth) acrylate monomer unit. May be. Examples of the copolymerizable monomer include a conjugated diene monomer, a non-covalent diene monomer, an aromatic vinyl monomer, an α, -ethylenically unsaturated nitrile monomer, and an amide group. Included are (meth) acrylic monomers, polyfunctional di (meth) acrylic monomers, and other olefin-based monomers.

[0038] Examples of the conjugated diene monomer include 1,3-butadiene, butadiene, chloroprene, and piperylene.

Examples of the non-conjugated diene monomer include 1,2-butadiene, 1,4-pentadiene, dicyclopentadiene, norbornene, ethylidene norbornene, 1,4-hexadiene, norbornadiene and the like.

Examples of the aromatic vinyl monomer include styrene, permethylstyrene, dibutylbenzene, and the like.

Examples of the α, β-ethylenically unsaturated nitrile monomer include acrylonitrile and methacrylonitrile.

Amide group-containing (meth) acrylic monomers include acrylamide and methacrylamide. I can get lost.

Other olefin monomers include ethylene, propylene, butyl chloride, butylidene chloride, butyl acetate, ethyl butyl ether, butyl butyl ether and the like. Of these, ethylene and vinyl acetate are preferred.

When a monomer other than the above (meth) acrylic acid ester monomer is copolymerized, 45% by weight or less, preferably 15% by weight or less, based on 100% by weight of the whole acrylic rubber (B1), More preferably, it is desirable to incorporate it in a proportion of 5% by weight or less and copolymerize.

[0040] Further, as another monomer copolymerizable with the above-mentioned (meth) acrylic acid ester monomer, a crosslinkable group-containing monomer containing a crosslinkable group suitable for dynamic crosslinking may be used. Is preferred. Examples of such a crosslinkable group-containing monomer include a monomer having a halogen-containing group, an epoxy group or a hydroxyl group.

Examples of the monomer having a halogen-containing group include halogen-containing vinyl ethers such as 2-chloroethyl butyl ether; halogen-containing styrene derivatives such as chloromethylstyrene; halogen-containing vinyl acetates such as vinyl chloride acetate; Is mentioned.

[0042] Examples of the epoxy group-containing monomer include aryl glycidyl ether and glycidyl (meth) acrylate.

Examples of the carboxyl group-containing monomer include ethylenically unsaturated monocarboxylic acids or ethylenically unsaturated polycarboxylic acids such as acrylic acid, methacrylic acid, itaconic acid, fumaric acid, and maleic acid; monobutyl maleate and fumaric acid. Butenedionic acid monobutenedionic acid monocycloalkyl ester such as monobutyl acid; and the like.

[0044] The amount of the crosslinkable group-containing monomer to be used is preferably 0.5 to 10% by weight, more preferably 115 to 5% by weight, based on all the polymerized monomers. If the amount of the cross-linkable group-containing monomer is too small, the dynamic cross-linking does not proceed sufficiently and the dispersibility of the rubber may be impaired. Conversely, if the amount is too large, the polymerization process of the acrylic rubber (B1) may be performed. The rubber (B1) may not be polymerized stably.

[0045] When the acrylic rubber (B1) contains a gel component, as a monomer copolymerizable with the (meth) acrylic acid ester monomer, spontaneous crosslinking occurs during the polymerization reaction. Possible It is preferable to use an unsaturated crosslinkable group-containing monomer having two or more butyl groups.

Examples of the unsaturated cross-linkable group-containing monomer include polyfunctional bur compounds such as dibutylbenzene and 1,3,5-trivinylbenzene; and diaryl such as diaryl phthalate and diaryl fumarate. Compounds; polyfunctional atalylates such as trimethylolpropane triatalylate and ethylene dalcol dimethacrylate; and the like.

[0047] The amount of the unsaturated crosslinkable group-containing monomer used is preferably 0.2 to 1.5% by weight, more preferably 0.2 to 1.5% by weight, based on the total amount of monomers used for polymerization of the acrylic rubber (B1). Is 0.3-1.0% by weight.

[0048] Nitrile rubber (B2)

The nitrile rubber (B2) is a rubber obtained by copolymerizing an α, ethylenically unsaturated nitrile monomer, a conjugated diene monomer and other monomers copolymerizable therewith as required. It is.

[0049] Examples of the a, β-ethylenically unsaturated nitrile monomer include acrylonitrile, methacrylonitrile, and α-methyl acrylonitrile, among which acrylonitrile is preferable. The amount of the α, -ethylenically unsaturated nitrile monomer used in the copolymerization of nitrile rubber (Β2) is preferably 30 to 80% by weight, more preferably 35 to 60% by weight, based on all monomers used for the polymerization. %. If the amount of a, j3_ethylenically unsaturated nitrile monomer is too small, the oil resistance may be poor, and if it is too large, the cold resistance may be poor.

[0050] Examples of the conjugated diene monomer include 1,3-butadiene, isoprene, 2,3-dimethyl-1,3-butadiene, and 1,3-pentadiene. Among them, 1,3_butadiene is preferred.

[0051] The monomer that can be added as necessary and that can be copolymerized with the above monomer includes a crosslinkable group-containing monomer suitable for dynamic crosslinking, as described in the description of the acrylic rubber (B1). In addition, a monomer containing an unsaturated crosslinkable group suitable for containing a gel can be used in the same amount as described above.

[0052] Hydrogenated nitrile rubber (B3)

Hydrogenated nitrile rubber (B3) is used to remove carbon-carbon unsaturated bonds in the main chain of nitrile rubber (B2). It is a rubber made by hydrogenation.

[0053] Also in the hydrogenated nitrile rubber (B3), the same kinetics as described in the description of the acrylic rubber (B1) as a monomer copolymerizable with the above-mentioned monomer, which can be cured if necessary. A cross-linkable group-containing monomer suitable for selective cross-linking, an unsaturated cross-linkable group-containing monomer suitable for containing a gel, and the like can be used in the same amounts as described above.

[0054] Epihalohydrin rubber (B4)

The epihalohydrin rubber (B4) may be referred to as an epihalohydrin monomer (b41) [hereinafter sometimes referred to as “monomer (b41)”. Or a ring-opened copolymer of the monomer (b41) and a monomer copolymerizable therewith.

As the ephalohydrin monomer (b41), a force S such as epichronorehydrin, epib mouth mohydrin, 2-methylhepiclorhydrin and the like are preferable, and among them, epichlorhydrin is preferable.

As the monomer copolymerizable with the monomer (b41), the alkylene oxide monomer (b42) [hereinafter sometimes referred to as “monomer (b42)”. ] And an epoxy group-containing crosslinkable monomer (b43) [hereinafter sometimes referred to as “monomer (b43)”. And the like.

Examples of the alkylene oxide monomer (b42) include chain alkylene oxides such as ethylene oxide, propylene oxide, and 1,2-epoxy-14-cyclopentane; 1,2-epoxycyclopentane; Cyclic alkylene oxides such as 1,2-epoxycyclohexane; and the like.

[0058] Examples of the epoxy group-containing crosslinkable monomer (b43) include glycidyl ether group-containing compounds such as aryl glycidyl ether and bullet glycidyl ether; and glycidyl ester group-containing compounds such as glycidyl (meth) atalylate and glycidyl crotonate. 3,4-epoxy-1-butene and other epoxy-containing unsaturated hydrocarbons;

[0059] Among the monomers (b42), ethylene oxide and propylene oxide are preferably used for the purpose of imparting rubber elasticity to the ephalohydrin rubber (B4). Further, the monomer (b43) is used when the epihalohydrin rubber (B4) contains a gel component, and is preferably arylglycidyl ether.

[0060] In addition, when the ephalohydrin rubber (B4) is dynamically crosslinked, the no and logen atoms of the monomer (b41) can be used. [0061] The ratio of the monomer unit content of the epihalohydrin rubber is preferably in the following range.

That is, the monomer (b41) units, preferably 20- 100 Monore ^_0/0, more preferably 25 9 0 mole ^_0/0; monomer (b42) units, preferably 0 75 Monore ⁰ / ₀ , more preferably 10 to 70 mol%; the monomer (b43) unit is preferably 15 mol% or less, more preferably 10 mol% or less.

[0062] If the unit content of the monomer (b41) is too small, the molded article may have high hygroscopicity, and if too large, the molded article may have poor cold resistance. If the monomer (b42) unit content is too large, foaming may occur during molding.

[0063] Polymerization of rubber (B)

The acrylic rubber (B1), nitrile rubber (B2), and ephalohydrin rubber (B4) used in the present invention can be obtained by polymerizing each of the above rubber-forming monomers by a known polymerization method. it can. Specifically, the acrylic rubber (B1) and nitrile rubber (B2) can be obtained by emulsion polymerization and the like, and the ephalohydrin rubber (B4) can be obtained by solution polymerization and solvent slurry polymerization.

[0064] The hydrogenated nitrile rubber (B3) is produced by hydrogenating carbon-carbon unsaturated bonds of the nitrile rubber (B2). More specifically, an aqueous layer hydrogenation method in which the latet after the emulsion polymerization of nitrile rubber (B2) is adjusted to a concentration of about 20% by weight and then hydrogenates against carbon-carbon unsaturated bonds in the rubber, Alternatively, an oil layer hydrogenation method of hydrogenating a carbon-carbon double bond in a rubber in a solution of nitrile rubber (B2) in an organic solvent is exemplified. In the hydrogenation reaction, a compound of a platinum group element such as palladium is added as a catalyst to the above-mentioned aqueous or oil-based reaction solution contained in a pressure-resistant closed vessel, and the dissolved oxygen is depressurized, purged with an inert gas or hydrogen, etc. After removing with, usually, hydrogen is sealed at a pressure of 0.5-20 MPa at 5-150 ° C. The hydrogenation rate is usually at least 70%, preferably at least 80%.

The rubber (B) obtained by these production methods may have a core-shell structure comprising a core layer of a crosslinked rubber and a shell layer of a rubber having a crosslinkable group.

[0066] Method for producing thermoplastic elastomer composition

The thermoplastic elastomer composition of the present invention comprises a polyamide resin (A1) or a polyester resin. Resin (A2) and at least one resin selected from the group consisting of acrylic rubber (B1), nitrile rubber (B2), hydrogenated nitrile rubber (B3) and ephalohydrin rubber (B4) And the rubber (B) is dynamically kneaded while kneading.

[0067] Dynamic crosslinking is a process in which the resin (A) and the rubber (B) are kneaded to finely disperse the rubber (B) in a matrix of the resin (A), and the rubber (B) is mixed with a crosslinking agent. Means cross-linking. The thermoplastic elastomer composition of the present invention obtained by performing dynamic crosslinking can provide a molded article having improved mechanical strength and fatigue resistance to bending and constant elongation.

[0068] In the present invention, as a crosslinking agent for dynamic crosslinking, a crosslinking agent generally used as a crosslinking agent for rubber can be used, but depending on the type of the crosslinking group of the rubber). It is preferable to use the following.

That is, when the crosslinkable group is a halogen-containing group, examples thereof include a sulfur-based crosslinking agent (which may be accompanied by a metal fossil) and a triazine-based crosslinking agent.

When the crosslinking group is an epoxy group, examples thereof include an organic ammonium-based crosslinking agent, an imidazole-based crosslinking agent, and a polyacid-based crosslinking agent.

When the crosslinkable group is a carboxyl group, a polyamine crosslinker, a diisocyanate crosslinker and the like can be mentioned.

[0069] In the present invention, the ratio of the resin (A) to the rubber (B) used is A: B = 20: 80-95: 5, preferably A: B = 50: 50-80, by weight ratio. : 20. If the amount of the rubber (B) is too small, the permanent compression set may increase. Conversely, if the amount is too large, the dispersion of the rubber (B) at the time of dynamic crosslinking becomes insufficient, and the processability may decrease. There is.

[0070] The amount of the crosslinking agent to be used is preferably 0.1 to 2 parts by weight, more preferably 0.5 to 1 part by weight, based on 100 parts by weight of the total of the resin (A) and the rubber (B). Department. If the amount of the cross-linking agent is too small, the cross-linking during dynamic cross-linking does not proceed sufficiently, and the dispersion of the rubber (B) in the resin (A) becomes insufficient, which may increase the compression set. Conversely, if the amount is too large, the decomposition of the resin (A) may be accelerated.

[0071] The method of dynamic crosslinking may be any general dynamic crosslinking method, for example, the following method. First, the rubber (B) is kneaded with a kneading machine usually at 160 to 300 ° C, preferably 180 to 250 ° C, while giving shearing force. Next, the resin (A) is added to the mixture and kneaded. The rubber (B) is dispersed in the matrix of the molten resin (A). Next, when the rubber (B) is sufficiently finely dispersed in the matrix of the resin (A), the crosslinking agent is added and further kneaded to crosslink the rubber (B).

[0072] If the kneading temperature is too low, the resin (A) may not melt sufficiently, and if it is too high, the rubber (B) may be thermally degraded.

As the kneader, a batch kneader such as a Brabender or Labo Plastomill; a continuous kneader such as a single screw extruder or a twin screw extruder can be used.

When using a continuous kneader such as an extruder, the crosslinking agent is preferably added through an addition hole provided in the middle of the barrel of the extruder.

[0073] The thermoplastic elastomer composition of the present invention may contain, as long as the effects of the present invention are not impaired, fillers such as carbon black and silica; antioxidants; lubricants; You may mix and use the compounding agent generally mix | blended.

[0074] The thermoplastic elastomer composition of the present invention obtained by the above method is a crosslinked rubber (B

) Particles are finely dispersed in the matrix of the resin (A), and have the properties of a thermoplastic elastomer.

Since the composition of the present invention is a thermoplastic elastomer, it can be extruded at 160 to 350 ° C., such as extrusion molding, injection molding, transfer molding, compression molding, calendar molding, etc., like a normal thermoplastic resin. By molding by the method, a molded article of an arbitrary shape can be obtained.

[0076] The molded article of the present invention thus obtained has rubber elasticity, is excellent in heat resistance, oil resistance, and mechanical properties, and is excellent in fatigue resistance with small compression set. Therefore, various rubber parts related to automobiles, such as seal parts such as shaft seals and bearing seals; hose parts such as air duct hoses, fuel hoses, and oil hoses; boots such as constant velocity joint boots and rack and pinion boots; It is preferably used as Example

[0077] The present invention will be described more specifically with reference to examples and comparative examples. The present invention is not limited to these examples. Unless otherwise indicated, “parts” and “%” are based on weight. Various physical properties in Examples, Comparative Examples and Reference Examples Was measured by the following method.

(0078) Melting point

The melting points of the polyamide resin (A1) and the polyester resin (A2) were determined from the peak temperature of heat of fusion using a differential scanning calorimeter.

[0079] (2) Flexural modulus

The flexural modulus of the polyamide resin (A1) and the polyester resin (A2) was measured at 23 ° C. according to JIS D790.

[0080] (3) Tensile strength and tensile elongation at break

The thermoplastic elastomer composition was molded by a press machine preheated to 250 ° C. to obtain a sheet having a thickness of 2 mm. Then, this sheet was punched into a predetermined shape to prepare a test piece. Using the obtained test pieces, the tensile strength and tensile elongation at break were measured in accordance with the tensile test of JIS K6251.

[0081] (4) Heat resistance

A test piece was prepared in the same manner as the test piece for which the tensile strength and tensile elongation at break were measured in the above (3). The obtained test specimen was allowed to stand in an environment of 150 ° C for 70 hours, aged by air heating, and the tensile strength was measured again using the aged test specimen according to the method (3). Then, the amount of change (rate of change in tensile strength:%) from the measured value in the above (3) was determined, and the heat resistance was evaluated. The closer this change is to 0, the better the heat resistance.

[0082] (5) Hardness

Hardness of Thermoplastic Elastomer Composition The hardness was measured according to a hardness test of IS K6253.

[0083] (6) Compression set

In accordance with JIS K6262, a test piece for measuring compression set was prepared by injection molding, and the obtained test piece was used to perform compression set at 25% compression rate and 120 ° C for 70 hours under compression conditions. Was measured.

(7) Fatigue resistance

A test piece punched out of a 2 mm sheet into a predetermined shape is prepared, and the test piece is stretched to half the breaking elongation, and then returned to 0% elongation at a rate of 300 times / min. And the number of times until the test piece was broken was measured. Many breaks The higher the degree, the better the fatigue resistance.

[0085] (8) Mooney viscosity

For the rubber (B), the Mooney viscosity ML at a measurement temperature of 100 ° C. was measured according to the Mooney viscosity test of the uncrosslinked rubber physical test method of JIS K6300.

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[0086] (9) Content of gel component in rubber (B)

The gel content in the rubber (B) was determined by measuring the proportion of the solvent-insoluble component when the rubber (B) was dissolved in a good solvent. Specifically, first, about 0.2 g of the rubber (B) is weighed, dissolved in methyl ethyl ketone, and the obtained solution is filtered through a filter such as a wire mesh. Then, the weight of the insoluble matter trapped in the filter after removing the solvent was measured, and the ratio to the total weight of the dissolved rubber was calculated.

[0087] Reference Example 1

Manufacture of acrylic rubber (B11)

In a polymerization reactor equipped with a thermometer, a stirrer, a nitrogen inlet tube, and a decompression device, 200 parts of ion exchange, 3 parts of sodium lauryl sulfate, 47 parts of ethyl acrylate, 50 parts of n-butyl acrylate, 50 parts of ethylene glycol One part of tatalylate and 2 parts of monomethyl fumarate were charged, and deaeration under reduced pressure and nitrogen substitution were repeated twice to sufficiently remove oxygen. Then, 0.002 parts of sodium formaldehyde sulfoxylate and 0.005 parts of cumoxide at the mouth are added, and the emulsion polymerization reaction is started at 20 ° C under normal pressure, and the reaction is continued until the polymerization conversion reaches 95% or more. went. The obtained latex was coagulated with an aqueous calcium chloride solution and drained, and the crumb was washed with water and dried to obtain a carboxy group-containing acrylic rubber (Bl 1). The gel fraction of the obtained carboxyl group-containing acrylic rubber (B11) was 80%, and the Mooney viscosity ML (100 ° C) was 45.

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[0088] Reference Example 2

Production of hydrogenated nitrile rubber (B31)

In a polymerization reactor equipped with a thermometer, a stirrer, a nitrogen inlet tube and a decompressor, put 200 parts of ion-exchanged water, 3 parts of sodium lauryl sulfate, 30 parts of acrylonitrile, 67 parts of butadiene, 2 parts of methacrylic acid, and 1 part of dibutylbenzene. Then, degassing under reduced pressure and nitrogen replacement were repeated twice to sufficiently remove oxygen. And sodium formaldehyde sulfoxylate 0.002 parts and 0.005 parts of cumenehydride peroxide were dried, and the emulsion polymerization reaction was started at 10 ° C and normal pressure.The reaction was continued until the polymerization conversion reached 95% or more. A tolyl rubber latex was obtained. Next, 4 liters (480 g total solids) of a carboxyl group-containing nitrile rubber latex adjusted to a total solid content of 12% by weight using this latex was charged into a 10 liter autoclave equipped with a stirrer, and nitrogen gas was added for 10 minutes. After removing the dissolved oxygen in the latex by flowing, palladium acetate as a hydrogenation catalyst was dissolved in 2.4 liters of 4 times the molar amount of water and added. After replacing the inside of the system with hydrogen gas twice, the content was adjusted to 50 ° C and pressurized with hydrogen gas to 3MPa, hydrogenation reaction was performed for 6 hours, then coagulated with calcium chloride, washed with water and dried Thus, a carboxyl group-containing hydrogenated nitrile rubber (B31) having a hydrogenation ratio of 95% was obtained.

The gel content of the obtained rubber (B31) is 85%, and the Mooney viscosity ML (100 ° C) is 80.

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It was.

Example 1

Kneading of polyamide tree flum (Al 1) and acrylic rubber (Bl 1)

Using a Toyo Seiki Labo Plastomill (volume: 600 ml), 40 parts of acrylic rubber (B11) was placed in a mixer preheated to 230 ° C, and masticated for 1 minute. Then, a polyamide resin (All: 6-nylon, average degree of polymerization 430, melting point 214 ° C, flexural modulus 6,500 kgf / cm ² , butylbenzenesulfonamide (plasticizer) containing 15% by weight in the mixer was used. 60 parts were added and mixed for 5 minutes, and then 0.5 parts of hexamethylene diamine carbamate (crosslinking agent) was added and mixed for another 7 minutes.

After completion of the mixing, the mixture was immediately taken out and pressed with a press machine that had not been preheated to obtain a sheet-like sample. This sample was pressed with a press machine preheated to 250 ° C. It was formed into a thick sheet. The obtained sheet-shaped sample was tested and evaluated by the methods described above. The results are shown in Table 1.

[0091] Example 2

Kneading of polyamide resin (A12) and acrylic rubber (Bl 1)

In Example 1, a polyamide resin (A12: 12-nylon, average degree of polymerization 220, melting point 170 ° C, flexural modulus 2,600 kgf / cm ² , n-octyl-4 -Hydroxybenzoate (containing 25% by weight of plasticizer)), kneading and dynamic cross-linking were performed in the same manner as in Example 1, and the test and evaluation were performed. The results are shown in Table 1.

[0092] Example 3

Kneading of polyamide resin (Al 1) and nitrile rubber (B21)

Example 1 is the same as Example 1 except that nitrile rubber (B21; Nipoll072J manufactured by Zeon Corporation, Mooney viscosity ML (100 ° C) 48) was used instead of the acrylic rubber (B11).

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The mixture was kneaded and dynamically crosslinked, and tested and evaluated. The results are shown in Table 1.

[0093] Example 4

Kneading of polyamide resin (All) and hydrogenated nitrile rubber (B31)

In Example 1, kneading and dynamic cross-linking were carried out in the same manner as in Example 1 except that a hydrogenated nitrile rubber (B31) was used instead of the acrylic rubber (B11), and a test and evaluation were performed. The results are shown in Table 1.

[0094] Example 5

Kneading of polyamide resin (All) and epihalohydrin rubber (B41)

In Example 1, instead of the acrylic rubber (B11), ephalohydrin rubber (B41; GechronlOO, manufactured by Nippon Zeon, Mooney viscosity ML (100 ° C) 58) was used, and magnesia oxide was used.

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Kneading and dynamic crosslinking were carried out and tested and evaluated in the same manner as in Example 1 except that 1 part of shim was added. The results are shown in Table 1.

[0095] Example 6

Kneading of polyester resin (A21) and hydrogenated nitrile rubber (B31)

In Example 4, a polyester resin (A21: polyethylene terephthalate, weight average molecular weight 83,000, melting point 210 ° C, flexural modulus 5,700 kgf / cm ² , phthalic acid-hydroxy Chinore 2_ Echiru hexyl Similarly kneaded with the exception of using the (plasticizer) 15 parts by weight ^_0/0 containing) example 4 performs dynamic crosslinking test was evaluated. The results are shown in Table 1.

[0096] Example 7

Kneading of polyamide resin (All) and acrylic rubber (B11)

In Example 1, the addition amount of the polyamide resin (All) was 35 parts, and the amount of the acrylic rubber (B11) was Kneading and dynamic crosslinking were performed in the same manner as in Example 1 except that the addition amount was changed to 65 parts, and a test and evaluation were performed. The results are shown in Table 1.

[0097] Comparative Example 1

Kneading of high flexural modulus polyamide resin and acrylic rubber (Bl 1)

In Example 1, a polyamide resin (All) was converted to a polyamide resin having a high flexural modulus (6-nape, UBE nylon 6 1030B, manufactured by Ube Industries, melting point 225 ° C, flexural modulus 26, OOOkgf Except for changing to Zcm ² ), kneading and dynamic crosslinking were performed in the same manner as in Example 1, and the test and evaluation were performed. The results are shown in Table 1.

[0098] Comparative Example 2

Kneading of low-point polyamide fat acrylic rubber (B11)

In Example 1, the polyamide resin (Al 1) was converted to a low-melting polyamide resin (nylon copolymer 1: Vestamide E40, Daicel. Degussa, melting point 150 ° C, flexural modulus 1,000 kgf / cm ² ) Except for the change, kneading and dynamic crosslinking were carried out in the same manner as in Example 1, and tests and evaluations were performed. The results are shown in Table 1.

[0099] [Table 1]

) Js 鳞 6 ¾ ¾2

* 1: UBE nylon 6 1013B (made by Ube Industries) * 2: Vestamide E40 (made by Daicel Degussa)

[0100] As shown in Table 1, all of the thermoplastic elastomer compositions satisfying the requirements of the present invention provided molded articles having excellent heat resistance, small compression set, and excellent fatigue resistance. Example 1-7).

[0101] On the other hand, a sheet obtained by press-molding a composition obtained by dynamically kneading rubber by kneading with an acrylic rubber using a polyamide resin having a too high flexural modulus has a large compression set. The result was poor fatigue performance (Comparative Example 1).

Also, a sheet obtained by press-molding a composition obtained by kneading with acrylic rubber using a polyamide resin having a melting point that is too low and dynamically crosslinking the rubber has a large compression set and low heat resistance. (Comparative Example 2).

Claims

The scope of the claims

At least one polyamide resin (A1) or polyester resin (A2) with a flexural modulus of 10,000 kgf / cm ² or less at a melting point of 160-300 ° C and a temperature of 23 ° C (A) 20-95% by weight When,

Acrylic rubber (B1), nitrile rubber (B2), a hydrogenated nitrile rubber (B3) and at least one rubber selected from the group consisting of Epiharohidorin rubber (B4) (B) 5- 80 wt ^_0/0, and kneading A thermoplastic elastomer composition dynamically crosslinked.

The resin (A) contains a plasticizer,

The rubber (B) contains a gel component,

3. The thermoplastic elastomer composition according to claim 1, wherein the content of the gel component is 30 to 100% by weight based on 100% by weight of the whole rubber (B).

14. The thermoplastic elastomer composition according to claim 13, wherein the rubber (B) particles are finely dispersed in a matrix of the resin (A).

A molded article obtained by molding the thermoplastic elastomer composition according to any one of claims 14 to 160 at 350 ° C.