JP7050629B2 - Thermoplastic elastomer composition - Google Patents

Description

The present invention relates to a thermoplastic elastomer composition used for various molded products such as automobile parts, electronic materials, home appliances, electric devices, medical tools, packaging materials, stationery and miscellaneous goods.

Thermoplastic polyester-based elastomers are materials having excellent moldability, high mechanical strength, and high oil resistance, and are widely used in automobile parts, electric / electronic parts, fibers, films, and the like. However, on the other hand, since the polymer main chain contains an ester bond, it is susceptible to hydrolysis, and when used in a high temperature atmosphere, oxidative deterioration is likely to occur, and performance such as strength and elongation deteriorates in a relatively short time. It is also known that a phenomenon called "heat aging" is likely to occur, which is a practical problem.

In response to such problems, Patent Document 1 describes a polyamide-based resin, a hindered phenol-based antioxidant, a sulfur-based antioxidant, and / or a phosphorus-based antioxidant in a polyether ester block copolymer. It is disclosed that when used in combination, a composition having excellent thermal stability and the appearance of a molded product can be obtained.

Japanese Unexamined Patent Publication No. 2-173059

Various stabilizers have been tried, such as using a polyamide resin in combination with a specific antioxidant as in Patent Document 1, to solve the problem that thermoplastic polyester elastomers are easily heat-aged. There is a need for more effective stabilizers that are not sufficient.

An object of the present invention is to provide a polyester-based thermoplastic elastomer composition having excellent heat aging resistance without impairing flexibility and mechanical strength.

As a result of diligent studies on the above-mentioned problems, the present inventors have found that the use of a piperazine-based copolymer improves the heat-resistant aging property of the polyester-based thermoplastic elastomer composition, and have completed the present invention. ..

The present invention contains the thermoplastic polyester elastomer A and 0.1 to 50 parts by mass of the piperazine copolymer B and 0.1 to 10 parts by mass of the antioxidant C with respect to 100 parts by mass of the thermoplastic polyester elastomer A. The present invention relates to a thermoplastic elastomer composition.

The thermoplastic elastomer composition of the present invention has an effect of being excellent in heat aging resistance without impairing flexibility and mechanical strength.

The thermoplastic elastomer composition of the present invention contains a thermoplastic polyester elastomer A, a piperazine copolymer B, and an antioxidant C.
Conventionally, attempts have been made to improve heat aging resistance by blending a polyamide resin and an antioxidant into a thermoplastic elastomer composition containing a thermoplastic polyester elastomer. It has been found that the piperazine-based copolymer has a particularly high effect on the improvement of heat aging resistance, and it has been completed.

The thermoplastic polyester elastomer A preferably has a hard segment and a soft segment from the viewpoint of flexibility and moldability.

As the hard segment of the thermoplastic polyester-based elastomer, an aromatic polyester block is preferable.

Aromatic polyester blocks include phthalic acid, terephthalic acid, isophthalic acid, 1,4- or 2,6-naphthalenedicarboxylic acid, 4,4'-diphenyldicarboxylic acid, 4,4'-diphenyletherdicarboxylic acid, 4,4'. -Aromatic dicarboxylic acid such as diphenylsulfone dicarboxylic acid, one or more of its alkyl esters and anhydrides, and 2 carbon atoms such as ethylene glycol, propylene glycol, trimethylene glycol, tetramethylene glycol and hexamethylene glycol. It is preferably a crystalline polyester block which is a polycondensate with one or more of the alkylene glycols of ~ 6.

Examples of the soft segment of the thermoplastic polyester-based elastomer include a polyester-type polymer block, a polyether-type polymer block, a polycarbonate-type polymer block, and the like, and among these, a polyether-type polymer block is preferable from the viewpoint of flexibility.

Examples of the polyester type polymer block include polycaprolactone, polyenan lactone, polycaprilolactone, and a polyalkylene ester formed by a condensation reaction between an aliphatic dicarboxylic acid compound and an aliphatic diol. Examples of the polyalkylene ester formed by the condensation reaction of the aliphatic dicarboxylic acid compound and the aliphatic diol include polybutylene adipate and the like.

As the polyether type polymer block, an aliphatic polyether block is preferable, and one mainly composed of polyalkylene ether glycol is more preferable.

The mass ratio (hard segment / soft segment) of the hard segment to the soft segment in the thermoplastic polyester elastomer A is preferably 20/80 to 80/20, more preferably 30/70 to 70 / from the viewpoint of heat aging resistance. It is 30.

The D hardness of the thermoplastic polyester elastomer A is preferably 15 to 90, more preferably 25 to 80, still more preferably 45 to 70, from the viewpoint of the flexibility of the thermoplastic elastomer composition.

From the viewpoint of heat resistance, the melting point of the thermoplastic polyester elastomer A is preferably 130 to 240 ° C, more preferably 140 to 230 ° C, and even more preferably 150 to 225 ° C.

The content of the thermoplastic polyester elastomer A in the composition of the present invention is preferably 30 to 99% by mass, more preferably 40 to 95% by mass.

The piperazine-based copolymer B is effective in improving heat aging resistance and oil resistance. The piperazine-based copolymer is a kind of polyamide resin in a broad sense, but in particular, it is a category of a copolymer resin by a cocondensation reaction of diamine and dicarboxylic acid, and the piperazine-based copolymer B in the present invention is a diamine. Examples thereof include a piperazine-based copolymerized polyamide resin obtained by a cocondensation reaction between a heterocyclic diamine which is a secondary amine such as piperazine and a dicarboxylic acid.

Examples of the dicarboxylic acid include adipic acid, azelaic acid, sebacic acid, dodecanedic acid and the like. Further, aminocarboxylic acids such as 11-aminoundecanoic acid and 12-aminododecanoic acid may be contained.

Further, even if the polyamide-based block copolymer has a polyamide block, if the polyamide block is a piperazine-based block copolymer containing a heterocyclic diamine unit, it can be used as the piperazine-based block copolymer B.

The polyamide-based block copolymer is also called a polyamide-based elastomer, and is preferably composed of a hard segment made of a polyamide block and a soft segment made of a polyol block or the like.

The polyamide block is preferably a polyamide copolymer block such as a copolymer obtained by polycondensation of amines and dibasic acids or a compound equivalent thereto, preferably 5 mol% or more in the monomer unit of amines. More preferably, 10 mol% or more is a heterocyclic diamine unit.

Soft segments include polyethylene glycol, poly (1,2- and 1,3-) propylene ether glycol, polytetramethylene ether glycol, polyhexamethylene ether glycol, block or random copolymer of ethylene oxide and propylene oxide, and ethylene oxide. Examples thereof include a block of and tetrahydrofuran and a random copolymer. A divalent phenol such as bisphenol A or hydroquinone may be contained in the monomer unit of the soft segment. A preferred soft segment is a polyether block from the standpoint of flexibility, with polytetramethylene ether glycol being more preferred.

The number average molecular weight of the soft segment by gel permeation chromatography (GPC) is preferably 200 to 6,000, more preferably 250 to 4,000.

The mass ratio (hard segment / soft segment) of the hard segment (polyamide block) to the soft segment in the polyamide-based block copolymer is preferably 5/95 to 95/5, more preferably 20/80 to 80/20, and further. It is preferably 30/70 to 70/30, and more preferably 40/60 to 60/40.

In the piperazine-based copolymer B in the present invention, when the thermoplastic polyester-based elastomer A is a block copolymer of aromatic polyester and polyether, the piperazine is more than the piperazine-based block copolymer from the viewpoint of heat aging resistance. A system-copolymerized polyamide resin is preferable. The solubility of the piperazine-based copolymer B in alcohol may be soluble or insoluble.

The content of the piperazine-based copolymer B is 0.1 to 50 parts by mass, preferably 0.3 to 30 parts by mass, based on 100 parts by mass of the thermoplastic polyester elastomer A from the viewpoint of heat aging resistance and mechanical strength. , More preferably 1 to 10 parts by mass.

The content of the piperazine-based copolymer B in the composition of the present invention is preferably 0.4 to 35% by mass, more preferably 0.5 to 33% by mass.

As the antioxidant C in the present invention, an aromatic amine-based antioxidant is preferable from the viewpoint of heat aging resistance.

Examples of the aromatic amine-based antioxidant include phenylnaphthylamine, 4,4'-dimethoxydiphenylamine, 4,4'-bis (α, α-dimethylbenzyl) diphenylamine, 4-isopropoxydiphenylamine and the like. Then, the aromatic secondary amine compound is preferable, and the diphenylamine-based compound is more preferable.

Examples of the antioxidant other than the aromatic amine-based antioxidant include hindered phenol-based antioxidants, sulfur-based antioxidants, phosphorus-based antioxidants, and the like.

Hindered phenolic antioxidants include 2,4-dimethyl-6-t-butylphenol, 2,6-di-t-butylphenol, 2,6-di-t-butyl-p-cresol, and hydroxymethyl-2. , 6-di-t-butylphenol, 2,6-di-t-α-dimethylamino-p-cresol, 2,5-di-t-butyl-4-ethylphenol, 4,4'-bis (2, 6-di-t-butylphenol), 2,2'-methylene-bis-4-methyl-6-t-butylphenol, 2,2'-methylene-bis (4-ethyl-6-t-butylphenol), 4, 4'-methylene-bis (6-t-butyl-o-cresol), 4,4'-methylene-bis (2,6-di-t-butylphenol), 2,2'-methylene-bis (4-methyl) -6-cyclohexylphenol), 4,4'-butylidene-bis (3-methyl-6-t-butylphenol), 4,4'-thiobis (6-t-butyl-3-methylphenol), bis (3-methyl-6-t-butylphenol) Methyl-4-hydroxy-5-t-butylbenzyl) sulfide, 4,4'-thiobis (6-t-butyl-o-cresol), 2,2'-thiobis (4-methyl-6-t-butylphenol) , 2,6-bis (2'-hydroxy-3'-t-butyl-5'-methylbenzyl) -4-methylphenol, 3,5-di-t-butyl-4-hydroxybenzenesulfonic acid diethyl ester, 2,2'-Dihydroxy-3,3'-di (α-methylcyclohexyl) -5,5'-dimethyl-diphenylmethane, α-octadecyl-3 (3', 5'-di-t-butyl-4'- Hydroxyphenyl) propionate, 6- (hydroxy-3,5-di-t-butylanilino) -2,4-bis-octyl-thio-1,3,5-triazine, hexamethylene glycol-bis [β- (3,,) 5-Di-t-butyl-4-hydroxyphenol) propionate], N, N'-hexamethylene-bis (3,5-di-t-butyl-4-hydroxyhydrocynic acid amide), 2,2-thio [Diethyl-bis-3 (3,5-di-t-butyl-4-hydroxyphenyl) propionate], 3,5-di-t-butyl-4-hydroxybenzenephosphonic acid dioctadecyl ester, tetrakis [Methyl-3 (3,5-di-t-butyl-4-hydroxyphenyl) propionate] methane, 1,3,5-trimethyl-2,4,6-tris (3,5-di- t-Butyl-4-hydroxybenzyl) benzene, 1,1,3-tris (2-methyl-4-hydroxy-5-di-t-butylphenyl) butane, tris (3,5-di-t-butyl- 4-Hydroxyphenyl) isocyanurate, tris [β- (3,5-di-t-butyl-4-hydroxyphenyl) propionyl-oxyethyl] isocyanurate, etc., among which tetrakis [methylene-3- (3,5-di-t-butyl-4-hydroxyphenyl) propionate] Those having a molecular weight of 500 or more, such as methane, are preferable.

Examples of the sulfur-based antioxidant include compounds containing sulfur such as thioether-based, dithioate-based, mercaptobenzimidazole-based, thiocarbanilide-based, and thiodipropion ester-based compounds, and among these, thioether-based compounds are preferable. A thioether-based antioxidant is a compound having at least one thioether bond in its molecular structure. Specifically, examples of the thioether-based antioxidant include dilong-chain alkylthiodipropionate (dilauryl-3,3'-thiodipropionate, distearyl-3,3'-thiodipropionate, etc.) and tetrakis. [Methylene-3- (long-chain alkylthio) propionate] alkane (for example, tetrakis [methylene-3- (dodecylthio) propionate] methane, etc.) and the like can be mentioned. Examples of the long-chain alkyl group include a linear or branched-chain alkyl group having 8 to 20 carbon atoms. These thioether-based antioxidants can be used alone or in combination of two or more.

Examples of the phosphorus-based antioxidant include phosphite-based compounds and phosphate-based compounds, and among these, phosphite-based compounds are preferable.

Phosphite compounds include tetrakis [2-t-butyl-4-thio (2'-methyl-4'-hydroxy-5'-t-butylphenyl) -5-methylphenyl] -1,6-hexamethylene. -Bis (N-hydroxyethyl-N-methyl semicarbazide)-diphosphite, tetrakis [2-t-butyl-4-thio (2'-methyl-4'-hydroxy-5'-t-butylphenyl) -5-methyl Phenyl] -1,10-decamethylene-di-carboxylic acid-di-hydroxyethylcarbonylhydrazide-diphosphite, tetrax [2-t-butyl-4-thio (2'-methyl-4'-hydroxy-5'-t) -Butylphenyl) -5-Methylphenyl] -1,10-Decamethylene-di-carboxylic acid-di-salicyloylhydrazide-diphosphite, tetrax [2-t-butyl-4-thio (2'-methyl-4) '-Hydroxy-5'-t-butylphenyl) -5-methylphenyl] -di (hydroxyethylcarbonyl) hydrazide-diphosite, tetrakis [2-t-butyl-4-thio (2'-methyl-4'-hydroxy) -5'-t-butylphenyl) -5-methylphenyl] -N, N'-bis (hydroxyethyl) oxamid-diphosphite and the like, but in the present invention, at least one PO bond or P = O. Phosphite compounds in which the bond is attached to an aromatic group are preferable. Examples of such phosphite compounds include tris (2,4-di-t-butylphenyl) phosphite, tetrakis (2,4-di-t-butylphenyl) 4,4'-biphenylene phosphonite, and bis (2). , 4-Di-t-Butylphenyl) pentaerythritol-di-phosphite, bis (2,6-di-t-butyl-4-methylphenyl) pentaerythritol-di-phosphite, 2,2-methylenebis (4) , 6-di-t-butylphenyl) octylphosphite, 4,4'-butylidene-bis (3-methyl-6-t-butylphenyl-di-tridecyl) phosphite, 1,1,3-tris (2) -Methyl-4-ditridecylphosphite-5-t-butyl-phenyl) butane, tris (mixed mono and di-nonylphenyl) phosphite, tris (nonylphenyl) phosphite, 4,4'-isopropylidenebis (Phenyl-dialkylphosphite), 3,9-bis (2,6-di-tert-butyl-4-methylphenoxy) -2,4,8,10-tetraoxa-3,9-diphosphaspiro [5.5] undecane, etc. Can be mentioned.

Among the hindered phenol-based antioxidants, sulfur-based antioxidants, and phosphorus-based antioxidants, sulfur-based antioxidants and hindered phenol-based antioxidants are preferable, and aromatic amines are preferable from the viewpoint of heat aging resistance. It is preferable to use a system-based antioxidant in combination with these antioxidants. That is, the antioxidant C preferably contains at least one of an aromatic amine-based antioxidant, a sulfur-based antioxidant, and a hindered amine-based antioxidant.

The content of the aromatic amine-based antioxidant is preferably 10 to 90% by mass, more preferably 20 to 80% by mass in the antioxidant C.

Mass ratio of aromatic amine-based antioxidants to sulfur-based antioxidants and / or hindered phenol-based antioxidants (aromatic amine-based antioxidants / (sulfur-based antioxidants and / or hindered phenol-based antioxidants) Agent)) is preferably 9/1 to 1/9, more preferably 8/2 to 2/8.

The content of the antioxidant C is 0.1 to 10 parts by mass, preferably 0.5 to 8 parts by mass, and more preferably 0.7 to 3 parts by mass with respect to 100 parts by mass of the thermoplastic elastomer elastomer A.

The content of the antioxidant C in the composition of the present invention is preferably 0.1 to 9% by mass, more preferably 0.2 to 8% by mass.

The composition of the present invention preferably contains the carbodiimide compound D from the viewpoint of mechanical strength and heat aging resistance.

The carbodiimide compound D has the formula (I) :.

(In the formula, n Rs may be different from each other, and are a divalent aliphatic hydrocarbon group having 1 to 18 carbon atoms, a divalent heterocyclic group having 3 to 12 carbon atoms, and 6 to 14 carbon atoms. It is a divalent aromatic hydrocarbon group, a divalent alicyclic hydrocarbon group having 3 to 13 carbon atoms, or a terminal hydroxyl group, and n is an integer of 1 to 15).
It has a structure represented by and can react with a carboxylic acid to carry out a cross-linking reaction.

In the formula (I), those having n of 1 include dicyclohexylcarbodiimide, diisopropylcarbodiimide, 1-ethyl-3- (3-dimethylaminopropyl) carbodiimide hydrochloride, and BEC (1-t-butyl-3-ethyl). Carbodiimide), CMC (1-cyclohexyl-3- (2-morpholinoethyl) carbodiimidemeth-p-toluenesulfonate) and the like are known by abbreviations.

In the formula (I), a linear polymer called polycarbodiimide is known as one having n or more, an aliphatic polycarbodiimide in which R is an aliphatic group and an aromatic having an aromatic group in R. It is roughly classified into polycarbodiimide. Aliphatic polycarbodiimides are preferable because they are more reactive than aromatics, and linear ones are more reactive than branched ones. The weight average molecular weight of polycarbodiimide is preferably 100 to 100,000, more preferably 500 to 10,000, from the viewpoint of safety and ease of handling.

The carbodiimide compound E can be produced, for example, by heating an organic isocyanate in the presence of a suitable catalyst to cause a decarbonation reaction to form a carbodiimide-binding group, and the formation of the carbodiimide ^- binding group is 2260 cm-. It can be confirmed by the disappearance of the absorption peak of the isocyanate group of ¹ and the formation of the absorption peak of the carbodiimide-binding group. In addition to the above-mentioned basic production method, the carbodiimide compound E can be obtained from, for example, US Pat. No. 2,941,956, JP-A-47-3279, JP-A-5-178954, JP-A-7-330849. The methods disclosed in the Gazette, etc., and J.M. Org. Chem. , 28, 2069 (1963), Chem. , Review 81, 619 (1981) and the like. Further, it can be carried out without a solvent as disclosed in JP-A-5-178954, JP-A-6-56950 and the like.

As a commercially available product of carbodiimide compound E, the carbodilite series manufactured by Nisshinbo Chemical Co., Ltd. is known. Among them, carbodilite HMV-15CA is a linear polymer of aliphatic carbodiimide with an isocyanate group at the terminal sealed. Yes, it is suitable for the present invention. On the other hand, as commercially available aromatic polycarbodiimide compounds, Stavaxol P, Stavaxol P-400, Stavaxol I (all manufactured by Rheinchemy Co., Ltd.) and the like are known.

The content of the carbodiimide compound D is preferably 10 parts by mass or less, more preferably 0.05 to 8 parts by mass, and further preferably 0.1 to 6 parts by mass with respect to 100 parts by mass of the thermoplastic polyester elastomer A from the viewpoint of moldability. It is a department.

The content of the carbodiimide compound D in the composition of the present invention is preferably 10% by mass or less, more preferably 0.05 to 5% by mass.

The composition of the present invention preferably further contains a styrene-based elastomer E from the viewpoint of heat aging resistance and flexibility.

As the styrene-based elastomer E, a block copolymer composed of a styrene block of a polymer made of a styrene-based monomer and a conjugated diene block of a polymer made of a conjugated diene, and a hydrogenated product thereof are preferable.

Examples of the styrene-based monomer constituting the styrene block include styrene, o-methylstyrene, p-methylstyrene, p-tert-butylstyrene, 1,3-dimethylstyrene, α-methylstyrene and the like.

Examples of the conjugated diene constituting the conjugated diene block include butadiene, isoprene, 1,3-pentadiene and the like.

The block copolymer consists of a hard segment composed of a styrene block unit and a soft segment composed of a conjugated diene block unit, and contains a styrene-based monomer unit in the block copolymer from the viewpoint of determining the overall physical properties. The amount is preferably 5 to 70% by mass, more preferably 10 to 60% by mass, still more preferably 20 to 50% by mass.

Hydrogenation of the block copolymer may be partial or total, but the hydrogenation reduces unsaturated bonds and provides heat resistance, weather resistance and mechanical strength. From these viewpoints, the hydrogenation rate is preferably 80% or more, more preferably 90% or more. The hydrogenation rate can be determined by measuring the content of carbon-carbon double bonds derived from the conjugated diene compound in the block copolymer before and after hydrogenation by ¹ H-NMR spectrum and measuring the measured values. can.

Specific examples of the hydrogenated block copolymer include a styrene-ethylene-butylene-styrene block copolymer, a styrene-ethylene / propylene-styrene block copolymer, and a styrene-ethylene-ethylene / propylene-styrene block copolymer. Combined, styrene-isobutylene-styrene block copolymer, styrene-butadiene rubber, acrylonitrile-butadiene rubber, pyridine-butadiene rubber, styrene-isoprene rubber, styrene-ethylene copolymer, styrene-butadiene-styrene block copolymer, styrene -Isoprene-styrene block copolymer, poly (α-methylstyrene) -polybutadiene-poly (α-methylstyrene), poly (α-methylstyrene) -polyisoprene-poly (α-methylstyrene), ethylene-propylene Examples include polymers, styrene-chloroprene rubber and the like. These may be used alone or as a mixture of two or more kinds, but from the viewpoint of raw material preparation and workability, styrene-ethylene / butylene-styrene block copolymer (SEBS), styrene-ethylene / propylene. -At least one selected from the group consisting of-styrene block copolymer (SEPS), styrene-ethylene-ethylene-propylene-styrene block copolymer (SEEPS), and styrene-isobutylene-styrene block copolymer (SIBS). Is preferable.

The content of the styrene-based elastomer E is preferably 200 parts by mass or less, more preferably 10 to 180 parts by mass, and further preferably 20 to 150 parts by mass with respect to 100 parts by mass of the thermoplastic elastomer-based elastomer A from the viewpoint of oil resistance. It is a mass part.

The content of the styrene-based elastomer E in the composition of the present invention is preferably 80% by mass or less, more preferably 5 to 70% by mass.

The composition of the present invention preferably further contains acrylic rubber F from the viewpoint of heat aging resistance and flexibility.

Acrylic rubber is a polymer in which an acrylic acid ester is contained in a monomer, and rubber elasticity is imparted by the acrylic acid ester. In the present invention, the acrylic acid ester is preferably a non-crosslinkable monomer such as an acrylic acid alkyl ester or an acrylic acid alkoxyalkyl ester, and two or more of these may be used, but an acrylic acid alkyl ester is more preferable. ..

When acrylic rubber F having a cross-linking point functional group is used, the acrylic rubber produced by the reaction between the molecular terminal functional group of the crystalline elastomer and the rubber cross-linking point functional group of the acrylic rubber and the grafted body of the crystalline elastomer are used. A strong interface is formed, further improving heat resistance and mechanical strength. From these viewpoints, the acrylic rubber F preferably has a functional group for forming a crosslinked structure, and examples of the functional group include an epoxy group, a carboxy group, an active chlorine-containing group, and the like. Of these, an epoxy group and a carboxy group are preferable, and an epoxy group is more preferable.

Therefore, in addition to the acrylic acid ester, the acrylic rubber F contains a functional monomer for forming a crosslinked structure, for example, a non-conjugated diene, a carboxy group-containing monomer, an epoxy group-containing monomer, and an activity. It is preferable that a hydrogen atom-containing monomer or the like is used.

Examples of the non-conjugated diene include alkylidene norbornene such as 4-methyl-1,4-hexadiene and etylidene norbornene.

Examples of the carboxy group-containing monomer include (meth) acrylic acid.

Examples of the epoxy group-containing monomer include glycidyl (meth) acrylate and allyl glycidyl ether.

Examples of the active hydrogen atom-containing monomer include 2-chloroethyl vinyl ether, vinyl benzyl chloride, vinyl chloroacetate and the like.

Examples of the monomer other than the acrylic acid ester and the functional monomer for forming the crosslinked structure include ethylene, propylene, and isobutane as the monomers that impart rubber elasticity to the copolymer together with the acrylic acid ester. Such as α-olefin, butadiene, isoprene, conjugated diene such as chloroprene and the like can be mentioned.

Other copolymerizable monomers include styrene substituted with substituents such as styrene, lower alkyl, lower alkoxy, halogen and vinyl, ethylenically unsaturated nitriles such as acrylonitrile, and alkyl groups such as methyl methacrylate. Examples thereof include an alkyl methacrylate ester having about 1 to 8 carbon atoms, tetrahydrobenzyl methacrylate, and divinylbenzene.

Suitable acrylic rubber F is a copolymer of an acrylic acid alkyl ester having an alkyl group having 1 to 8 carbon atoms and an epoxy group or a carboxy group-containing monomer (acrylic acid alkyl ester: 90 to 99.95 mol%, Epoxide group or carboxy group-containing monomer: 0.05 to 10 mol%), a copolymer of an acrylic acid alkyl ester having an alkyl group having 1 to 8 carbon atoms and ethylene and an epoxy group or carboxy group-containing monomer ( Acrylic acid alkyl ester: 10 to 89.95 mol%, ethylene: 10 to 80 mol%, epoxy group or carboxy group-containing monomer: 0.05 to 10 mol%) and the like.

The Mooney viscosity (ML1 + 4) of the acrylic rubber F in the present invention at 100 ° C. is preferably 10 to 150, more preferably 10 to 120, and even more preferably 15 to 80. Mooney viscosity is defined by JIS K6300 and can be used as an index of melt fluidity related to moldability. Mooney viscosity varies depending on various factors such as composition and molecular weight. The smaller the viscosity, the better the melt fluidity, while the larger the viscosity, the higher the strength of the composition.

The glass transition temperature of the acrylic rubber F is preferably -100 to 10 ° C, more preferably −90 to 0 ° C, and even more preferably -40 to -10 ° C.

The content of acrylic rubber F is preferably 200 parts by mass or less, more preferably 10 to 180 parts by mass, and further preferably 20 to 150 parts by mass with respect to 100 parts by mass of the thermoplastic polyester elastomer A from the viewpoint of heat resistance deformation. It is a mass part.

The content of acrylic rubber F in the composition of the present invention is preferably 80% by mass or less, more preferably 5 to 70% by mass.

The composition of the present invention contains other thermoplastic resins and thermoplastic elastomers such as NBR (nitrile rubber), polyurethane rubber, epichlorohydrin rubber, and acrylic thermoplastic elastomers as long as the effects of the present invention are not impaired. You may.

The composition of the present invention is, if necessary, a polyolefin resin such as polypropylene or polyethylene, a softening agent, various flame retardant agents, a cross-linking agent, particularly an epoxy-based cross-linking agent, carbon black, as long as the effect of the present invention is not impaired. Reinforcing agents such as silica, carbon fiber and glass fiber, inorganic fillers, insulating heat conductive fillers, outer lubricants such as calcium stearate and zinc stearate, plasticizers, pigments, antistatic agents, tackifiers and cross-linking aids. , A heat stabilizer, a light stabilizer, an ultraviolet absorber, an anti-blocking agent, a sealability improving agent, a mold release agent, a coloring agent, a fragrance and the like may be contained.

The thermoplastic elastomer composition of the present invention contains a thermoplastic polyester elastomer A, a piperazine copolymer B, an antioxidant C, and if necessary, a carbodiimide compound D, a styrene elastomer E, an acrylic rubber F, and the like. It is obtained by mixing the containing raw materials and solidifying them by cooling.

The "mixing" referred to in the present invention is not particularly limited as long as it is a method in which various components are well mixed, and the various components may be dissolved in a soluble organic solvent and mixed, or by melt kneading. It may be mixed.

The thermoplastic elastomer composition can be used by directly molding the product obtained by melt-mixing into a molded product, or by using pellets or powder before forming a molded product to be used as a final product, depending on the application. , Sheets and other intermediate products. For example, it is melt-mixed by an extruder, extruded into a strand, and cut into pellets such as cylinders and rice granules by a cutter while being cooled in cold water. The obtained pellets can usually be made into a predetermined sheet-shaped molded product or mold-molded product by a molding method such as injection molding, extrusion molding, or press molding.

The D hardness of the thermoplastic elastomer composition of the present invention is preferably 90 or less, more preferably 85 or less, still more preferably 80 or less from the viewpoint of flexibility, and preferably 5 from the viewpoint of heat aging resistance. The above is more preferably 7 or more, still more preferably 10 or more.

A molded product can be obtained by appropriately heat-molding the thermoplastic elastomer composition of the present invention according to a conventional method. The application of the molded product obtained by heat-molding the thermoplastic elastomer composition of the present invention is not particularly limited, and general polyester-based elastomers, polyolefin-based elastomers, styrene-based elastomers, polyurethane-based elastomers, and polyamide-based elastomers are used. , Acrylic elastomer and the like can be used in the field where it is used.

As the apparatus used for producing a molded product using the thermoplastic elastomer composition of the present invention, any molding machine capable of melting the molding material can be used. For example, a kneader, an extrusion molding machine, an injection molding machine, a press molding machine, a blow molding machine, a mixing roll and the like can be mentioned.

Hereinafter, the present invention will be specifically described with reference to Examples, but the present invention is not limited to these Examples. Various physical properties of the raw materials used in Examples and Comparative Examples were measured by the following methods.

<Component A: Thermoplastic Elastomer>
[Hard segment (HS) / Soft segment (SS)]
The mass ratio (HS / SS) of the hard segment to the soft segment is proton NMR at 25 ° C. in a deuterated chloroform solvent using a nuclear magnetic resonance apparatus (DPX-400 manufactured by BRUKER, Germany). The measurement is performed and calculated from the signal intensity ratio of the methylene peak adjacent to various oxygens in the molecular structure.

[D hardness]
Measured according to JIS K 6253 Type D.

[Melting point]
The melting point is defined as the temperature of the melting peak obtained by raising the temperature at 10 ° C / min according to the method specified in JIS K 7121 using a differential scanning calorimetry (DSC) device. When multiple melting peaks appear, the melting peak that appears at a lower temperature is taken as the melting point.

<Component B: piperazine-based copolymer, etc.>
〔composition〕
The resin is solubilized by a pressurized acid decomposition method using hydrochloric acid, dried, and then dissolved in deuterated methanol and measured by proton NMR using an AVANCE III NMR device manufactured by bruker to measure the content of the piperazine component. In addition, the solution dissolved in methanol is subjected to an AcQuity liquid chromatography device manufactured by WATERS, and the monomer components constituting the polyamide resin are identified and quantified by mass spectrometry.

[D hardness]
Measure according to JIS K 6253-3 Type D.

[Melting point]
Put about 10 mg of the sample in an aluminum pan and crimp the aluminum lid. An aluminum pan is installed in the device measurement section of a differential scanning calorimeter (PerkinElmer DSC8000), and measurements are taken in the air at a temperature rise rate of 20 ° C / min in accordance with the method specified in JIS K 7121.

<Component D: Polycarbodiimide>
[Weight average molecular weight]
The carbodiimide compound is dissolved in tetrahydrofuran (THF), filtered through a microfilter, and subjected to gel permeation chromatography (GPC) using THF as an eluent to determine the weight average molecular weight based on the retention time of the polystyrene standard material. ..

<Component F: Acrylic rubber>
[Monomer composition]
Using a gas chromatograph mass spectrometer (gas chromatograph 7890A manufactured by Agilent Technologies, Inc., mass spectrometer Jms-Q1000GC K9 manufactured by JEOL Ltd.), heat-decompose the sample at 550 ° C and perform mass spectrometry of the thermally decomposed product. By doing so, the monomer composition is analyzed.

[Moony viscosity]
In accordance with the method specified by JIS K6300, measure the Mooney viscosity (ML1 + 4) after 1 minute of preheating at 100 ° C and 4 minutes after the start of rotation.

[Glass transition temperature (Tg)]
Calculated by weighted averaging the Tg of the constituent homopolymers according to the composition.

Examples 1 to 8 and Comparative Examples 1 to 8
(1) Preparation of Thermoplastic Elastomer Composition (Pellet) The raw material components were put into a mixer with the formulation (mass ratio) shown in Table 5 and dry-blended.

Then, the obtained mixture was melt-kneaded with an extruder (continuous kneader) under the following conditions to produce pellets of a thermoplastic composition.
[Melting and kneading conditions]
Extruder: KZW32TW-60MG-NH (manufactured by Technobel Co., Ltd.)
Cylinder temperature: 180-260 ℃
Screw rotation speed: 200-650r / min

Details of the raw materials shown in Table 5 used in Examples and Comparative Examples are as follows.

(2) Preparation of molded body of thermoplastic elastomer composition Pellets were injection-molded under the following conditions to prepare a press sheet having a thickness of 2 mm, a width of 125 mm and a length of 125 mm.

[Injection molding conditions]
Injection molding machine: 100MSIII-10E (trade name, manufactured by Mitsubishi Heavy Industries, Ltd.)
Injection molding temperature: 200 ° C
Injection pressure: 30%
Injection time: 3sec
Mold temperature: 40 ℃

The compositions obtained in Examples and Comparative Examples were evaluated as follows. The results are shown in Table 5.

[Flexibility (D hardness)]
The press sheet was allowed to stand in a constant temperature and humidity chamber (temperature 23 ° C., relative humidity 50%) for 24 hours or more to stabilize the state of the sheet. Three 2 mm thick press sheets were stacked and the D hardness was measured according to JIS K7215 "Plastic Durometer Hardness Test Method".

[Mechanical strength (tensile fracture stress and fracture elongation)]
From the press sheet, use a die-cutting machine to prepare the No. 3 test piece (length 20 mm) described in JIS K7113, and use a tensile tester (Autograph AG-50kND type) manufactured by Shimadzu Corporation to 23. The test piece was pulled at a speed of 200 mm / min in a temperature environment of ° C. The stress (MPa) at break of the test piece was recorded as the tensile fracture stress. In addition, the elongation at break ((length of test piece at break (mm) -20) / 20 × 100,%) was calculated from the length of the test piece at break.

[Heat-resistant aging]
From the press sheet, use a die-cutting machine to prepare the No. 3 test piece (length 20 mm) described in JIS K7113, and use the gear oven A45A2 type manufactured by Toyo Seiki Co., Ltd. at 150 ° C for 250 hours, and then 500 hours. The stored test pieces were subjected to a tensile test of mechanical strength. The length of the test piece at the time of breaking was measured, and the elongation retention rate (%) with respect to the breaking elongation rate of the test piece before storage was calculated. That is, when the breaking elongation rate after storage of the test piece having the breaking elongation rate of 100% before storage was 80%, the elongation retention rate was calculated to be 80% (80/100 × 100). "Collapse" indicates a state in which the test piece has collapsed due to storage at a high temperature.

From the above results, it can be seen that the thermoplastic elastomer compositions of Examples 1 to 8 have good heat aging resistance even after 500 hours. Among them, Example 5 in which an aromatic amine-based antioxidant is used in combination with a hindered phenol-based antioxidant and a sulfur-based antioxidant, Example 6 in which a carbodiimide compound is blended, and Example 7 in which a styrene-based elastomer is blended. In Example 8 in which acrylic rubber is blended, even higher heat aging resistance is exhibited.
On the other hand, in Comparative Examples 1 to 8, it can be seen that the piperazine-based copolymer is not blended and the heat-resistant aging property is insufficient. By blending a polyamide resin other than the piperazine-based copolymer as in Comparative Examples 2 to 4, the heat-resistant aging property is improved to the extent that it does not disintegrate even after 500 hours, but the piperazine-based copolymer is blended. Is far from that.

The thermoplastic elastomer composition of the present invention is used for various molded products such as electronic materials, home appliances, electric devices, medical tools, packaging materials, stationery and miscellaneous goods.

Claims (6)

A heat comprising 0.1 to 50 parts by mass of the piperazine-based copolymer B and 0.1 to 10 parts by mass of the antioxidant C with respect to 100 parts by mass of the thermoplastic polyester-based elastomer A and the thermoplastic polyester-based elastomer A. A thermoplastic elastomer composition , wherein the piperazine-based copolymer B is a copolymer resin obtained by a cocondensation reaction between a diamine containing piperazine and a dicarboxylic acid . The thermoplastic elastomer composition according to claim 1, wherein the antioxidant C contains an aromatic amine-based antioxidant. The thermoplastic elastomer composition according to claim 2, wherein the antioxidant C further contains at least one of a sulfur-based antioxidant and a hindered phenol-based antioxidant. The thermoplastic elastomer composition according to any one of claims 1 to 3, further comprising a carbodiimide compound D. The thermoplastic elastomer composition according to any one of claims 1 to 4, further comprising a styrene-based elastomer E. The thermoplastic elastomer composition according to any one of claims 1 to 5, further comprising acrylic rubber F.