JP6582985B2 - Thermoplastic polyester elastomer composition - Google Patents

Description

  The present invention relates to a thermoplastic polyester elastomer composition that is flexible and excellent in heat aging resistance and water resistance. The present invention also relates to a molded article made of a thermoplastic polyester elastomer composition. More specifically, the present invention relates to a thermoplastic polyester elastomer composition that is optimal for intake system parts of an internal combustion engine such as an air duct, a resonator, a side branch, and an air cleaner.

  Thermoplastic polyester elastomers have long been made of crystalline polyesters such as polybutylene terephthalate (PBT) and polybutylene naphthalate (PBN), and polyoxyalkylene glycols such as poly (tetramethylene oxide) glycol (PTMG). And / or polyesters such as polycaprolactone (PCL) and polybutylene adipate (PBA) are known and put into practical use (for example, Patent Documents 1 and 2).

  However, polyester polyether type elastomers that use polyoxyalkylene glycols in the soft segment are superior in water resistance and low temperature properties, but are inferior in heat aging resistance, and polyester polyester type elastomers that use polyester in the soft segment are However, although it is excellent in heat aging resistance, it is known to be inferior in water resistance and low-temperature characteristics, and there is a demand for providing a thermoplastic polyester elastomer having both heat aging resistance and water resistance in a well-balanced manner.

  For example, a block polyether ester copolymer composition obtained by adding a polyamide resin and a hindered phenol-based antioxidant, a sulfur-based antioxidant and / or a phosphorus-based antioxidant to a polyether ester block copolymer (Patent Documents) 3) and a polyester elastomer resin composition obtained by adding an aromatic amine antioxidant, a hindered phenol antioxidant, a sulfur antioxidant, a phosphorus antioxidant and / or a polyamide resin to a polyester elastomer ( Patent Document 4) has been proposed, but in such a configuration, there is a problem that heat aging resistance is still insufficient for applications that require extremely heat aging resistance, such as automobile parts, particularly parts around automobile engines. .

  In addition, aromatic amine antioxidants and hindered polyester elastomers composed of a flexible polyester block copolymer and a high-hardness polyester block copolymer and a thermoplastic elastomer obtained by mixing a dynamically crosslinked thermoplastic elastomer. Thermoplastic elastomer resin composition (Patent Document 5) to which a heat-resistant agent composed of one or more of a phenol-based antioxidant, a sulfur-based antioxidant and a phosphorus-based antioxidant is added, and terephthalic acid and the others A thermoplastic elastomer resin composition in which a glycidyl-modified polyolefin, an antioxidant, and a polyamide resin are added to a thermoplastic elastomer obtained by mixing a polyester block copolymer having a hard segment composed of a dicarboxylic acid and a polyester resin (Patent Documents) 6) has been proposed.

  However, in Patent Document 5 and Patent Document 6, although the heat aging resistance is improved, the problem peculiar to the polyester-based resin that the hydrolysis easily occurs is not solved.

Japanese Patent Laid-Open No. 10-17657 JP 2003-192778 A Japanese Patent Laid-Open No. 2-173059 JP-A-8-277358 JP 2011-116856 A JP 2013-189550 A

  The present invention has been made in order to solve the above-described problems of the conventional thermoplastic polyester elastomer composition, and an object thereof is to provide a thermoplastic polyester elastomer composition that is flexible and has excellent heat aging resistance and water resistance. And

  As a result of intensive studies to solve the above problems, the present inventors have reached the following invention. That is, the present invention is as follows.

[1] A hard segment composed of a polyester composed of an aromatic dicarboxylic acid and an aliphatic diol or an alicyclic diol and a soft segment composed of an aliphatic polyether are the main constituent components, and the content of the soft segment is 3 to 3 The carbodiimide compound (C) 0.1-10 parts by mass, hindered phenolic oxidation with respect to 100 parts by mass in total of 40% by mass of the thermoplastic polyester elastomer (A) and the modified olefin elastomer (B). It is a thermoplastic polyester elastomer composition comprising 0.01 to 5 parts by mass of an inhibitor (D) and 0.01 to 5 parts by mass of a sulfur-based antioxidant (E), wherein (A) and (B ) Mass ratio ((A) / (B)) is 95/5 to 40/60, measured according to JIS K6251: 2010. In the tensile test, the molded article obtained from the thermoplastic polyester elastomer composition had an initial tensile breaking elongation of 550% or more and a tensile breaking elongation retention (%) after heat treatment at 150 ° C. for 250 hours was 70. %, And a tensile elongation at break (%) after boiling water treatment at 100 ° C. for 350 hours is 60% or more.
[2] The thermoplastic polyester elastomer composition according to [1], wherein the hard segment which is a constituent component of the thermoplastic polyester elastomer (A) is composed of polybutylene terephthalate.
[3] An ethylene oxide addition polymer (PPG-EO addition polymer) in which the soft segment as a constituent component of the thermoplastic polyester elastomer (A) is poly (tetramethylene oxide) glycol (PTMG) and / or poly (propylene oxide) glycol The thermoplastic polyester elastomer composition according to [1] or [2].
[4] A modified ethylene / α-olefin copolymer obtained by modifying the modified olefin elastomer (B) obtained by copolymerizing ethylene and an α-olefin having 3 to 20 carbon atoms. The thermoplastic polyester elastomer composition according to any one of [1] to [3].
[5] The carbodiimide compound (C) is a polycarbodiimide compound having 2 to 50 carbodiimide groups and an isocyanate group content of 0 to 5% by mass, according to any one of [1] to [4]. A thermoplastic polyester elastomer composition.
[6] The mass ratio ((A) / (B)) of the thermoplastic polyester elastomer (A) and the modified olefin elastomer (B) is 95/5 to 65/35. [5] The thermoplastic polyester elastomer composition according to any one of [5].
[7] A molded article comprising the thermoplastic polyester elastomer composition according to any one of [1] to [6].
[8] The molded product according to [7], wherein the molded product is an internal combustion engine intake system component.
[9] The molded article according to [8], wherein the internal combustion engine intake system component is any one of an air duct, a resonator, a side branch, and an air cleaner.

  According to the present invention, it is possible to obtain a thermoplastic polyester elastomer composition that is flexible and excellent in heat aging resistance and water resistance.

Hereinafter, the present invention will be described in detail.
The thermoplastic polyester elastomer (A) is composed of a hard segment and a soft segment, a hard segment composed of a polyester composed of an aromatic dicarboxylic acid and an aliphatic or alicyclic diol, and a soft segment composed of an aliphatic polyether. And the main component. As the hard segment, the polyester composed of an aromatic dicarboxylic acid and an aliphatic or alicyclic diol is preferably 70% by mass or more, and more preferably 80% by mass or more. As the soft segment, the aliphatic polyether is preferably 70% by mass or more, and more preferably 80% by mass or more.
In the thermoplastic polyester elastomer (A) used in the present invention, a normal aromatic dicarboxylic acid is widely used as the aromatic dicarboxylic acid constituting the hard segment polyester, and the main aromatic dicarboxylic acid is terephthalic acid. Alternatively, 2,6-naphthalenedicarboxylic acid is desirable. The terephthalic acid or 2,6-naphthalenedicarboxylic acid is preferably 70 mol% or more, more preferably 80 mol% or more of the total acid component. Other acid components include diphenyl dicarboxylic acid, isophthalic acid, aromatic dicarboxylic acid such as 5-sodium sulfoisophthalic acid, cycloaliphatic dicarboxylic acid, alicyclic dicarboxylic acid such as tetrahydrophthalic anhydride, succinic acid, glutaric acid, adipine Examples thereof include aliphatic dicarboxylic acids such as acid, azelaic acid, sebacic acid, dodecanedioic acid, dimer acid, and hydrogenated dimer acid. The other acid component is used within a range that does not significantly lower the melting point of the thermoplastic polyester elastomer, and the amount thereof is preferably 30 mol% or less, more preferably 20 mol% or less of the total acid component.

  Moreover, in the thermoplastic polyester elastomer (A) according to the present invention, the aliphatic or alicyclic diol constituting the hard segment polyester is widely used as a general aliphatic or alicyclic diol, and is not particularly limited. It is desirable that they are mainly alkylene glycols having 2 to 8 carbon atoms. Specific examples include ethylene glycol, 1,3-propylene glycol, 1,4-butanediol, 1,6-hexanediol, 1,4-cyclohexanedimethanol and the like. Of these, 1,4-butanediol or 1,4-cyclohexanedimethanol is preferred.

  As a component constituting the polyester of the hard segment, a butylene terephthalate unit composed of terephthalic acid and 1,4-butanediol, or a butylene naphthalate unit composed of 2,6-naphthalenedicarboxylic acid and 1,4-butanediol Is preferable from the viewpoint of physical properties, moldability, and cost performance. Those consisting of butylene terephthalate units are particularly preferred.

  Further, when an aromatic polyester suitable as a polyester constituting the hard segment in the thermoplastic polyester elastomer (A) according to the present invention is produced in advance and then copolymerized with a soft segment component, the aromatic polyester It can be easily obtained according to the production method of polyester. Moreover, what has the number average molecular weight 10000-40000 is desirable for this polyester.

  The aliphatic polyether which is a soft segment component in the thermoplastic polyester elastomer (A) used in the present invention is poly (ethylene oxide) glycol, poly (propylene oxide) glycol, poly (tetramethylene oxide) glycol, poly (hexamethylene oxide). And poly (alkylene oxide) glycols such as glycols, copolymers of ethylene oxide and propylene oxide, ethylene oxide addition polymers of poly (propylene oxide) glycol, and copolymers of ethylene oxide and tetrahydrofuran.

  Among the above aliphatic polyethers, poly (tetramethylene oxide) glycol (PTMG), poly (propylene oxide) glycol ethylene oxide addition polymer (PPG-EO addition polymer), ethylene oxide and tetrahydrofuran copolymer glycol (EO / (THF copolymerization glycol) is preferable, and poly (tetramethylene oxide) glycol (PTMG) and poly (propylene oxide) glycol ethylene oxide addition polymer (PPG-EO addition polymer) are more preferable. In addition, the number average molecular weight of these soft segments is preferably about 300 to 6000 in the copolymerized state.

  The content (copolymerization amount) of the soft segment of the thermoplastic polyester elastomer (A) used in the present invention is 3 to 40% by mass. Content of a soft segment becomes like this. Preferably it is 5-40 mass%, More preferably, it is 10-40 mass%, More preferably, it is 20-40 mass%. When the content (copolymerization amount) of the soft segment is less than 3% by mass, the flexibility and rubber elasticity as an elastomer are insufficient, and when it exceeds 40% by mass, the heat resistance decreases.

  The reduced viscosity of the thermoplastic polyester elastomer (A) used in the present invention is preferably 1.3 to 2.5 dl / g, more preferably 1.5 to 2.3 dl / g. 170-225 degreeC is preferable, as for melting | fusing point of the thermoplastic polyester elastomer (A) used for this invention, 170-220 degreeC is more preferable, and 180-210 degreeC is further more preferable.

  The thermoplastic polyester elastomer (A) used in the present invention can be produced by a known method. For example, a method in which a lower alcohol diester of a dicarboxylic acid, an excess amount of a low molecular weight glycol, and a soft segment component are transesterified in the presence of a catalyst and the resulting reaction product is polycondensed, a dicarboxylic acid and an excess amount of glycol and a soft An example is a method in which a segment component is esterified in the presence of a catalyst and the resulting reaction product is polycondensed.

The modified olefin elastomer (B) used in the present invention is a modified olefin elastomer, and is obtained by copolymerizing ethylene and an α-olefin having 3 to 20 carbon atoms. What modified | denatured the type | system | group copolymer is preferable.
The ethylene / α-olefin copolymer is a copolymer containing ethylene and at least one α-olefin having 3 to 20 carbon atoms as a constituent component, and is an α-olefin having 3 to 20 carbon atoms. Specific examples include propylene, 1-butene, 1-pentene, 1-hexene, 1-heptene, 1-octene, 1-nonene, 1-decene, 1-undecene, 1-dodecene, 1-tridecene, 1-tetradecene. 1-pentadecene, 1-hexadecene, 1-heptadecene, 1-octadecene, 1-nonadecene, 1-eicocene, 3-methyl-1-butene, 3-methyl-1-pentene, 3-ethyl-1-pentene, 4 -Methyl-1-pentene, 4-methyl-1-hexene, 4,4-dimethyl-1-hexene, 4,4-dimethyl-1-pentene, 4-ethyl-1 Hexene, 3-ethyl-1-hexene, 9-methyl-1-decene, 11-methyl-1-dodecene, 12-ethyl-1-tetradecene and combinations thereof. Among these α-olefins, α-olefins having 4 to 12 carbon atoms are preferable.

The olefin elastomer is preferably modified by an unsaturated carboxylic acid or a derivative thereof. Specific examples of unsaturated carboxylic acids or derivatives thereof include acrylic acid, methacrylic acid, maleic acid, fumaric acid, itaconic acid, crotonic acid, methylmaleic acid, methyl fumaric acid, citraconic acid, glutaconic acid and metal salts of these carboxylic acids. , Methyl hydrogen maleate, methyl hydrogen itaconate, methyl acrylate, ethyl acrylate, butyl acrylate, hydroxyethyl acrylate, methyl methacrylate, hydroxyethyl methacrylate, diethyl maleate, dimethyl itaconate, maleic anhydride, anhydrous Itaconic acid, citraconic anhydride, maleimide, N-ethylmaleimide, N-butylmaleimide, N-phenylmaleimide, glycidyl acrylate, glycidyl methacrylate, glycidyl itaconate, glycidyl citraconic acid, etc. Among the modified olefin-based elastomers, ethylene and an α-olefin copolymer having 4 to 12 carbon atoms modified with an unsaturated carboxylic acid and / or an acid anhydride thereof are preferable.
The reason why the olefin-based elastomer (B) needs to be modified is to improve the compatibility with the thermoplastic polyester elastomer (A) and to maximize the synergistic effect of the alloy. It is surprising that the heat aging resistance is dramatically improved by blending the modified olefin elastomer. In addition, since the compatibility is improved by modification, the extruded strands during melt kneading can be stably produced without pulsation.

The modified content of the olefin-based elastomer (B) is preferably 0.3 to 3.0% by mass, more preferably 0.5 to 2.0% by mass, and still more preferably 0.8 to 1.5% by mass. The modified content represents the content (copolymerization amount) of the compound (monomer) having a modifying group in the modified olefin elastomer (B).
As such a modified olefin elastomer, for example, “Tuffmer MH5020” manufactured by Mitsui Chemicals, Inc. can be used.

  In the present invention, when the total of the thermoplastic polyester elastomer (A) and the modified olefin elastomer (B) is 100 parts by mass, the thermoplastic polyester elastomer (A) and the modified olefin elastomer (B) The mass ratio ((A) / (B)) is 95/5 to 40/60, and preferably 95/5 to 50/50. In order to show the effect of the present invention remarkably, the mass ratio is preferably 95/5 to 65/35, more preferably 90/10 to 70/30, and still more preferably 90/10 to 75/25. Outside the above range, the flexibility, heat resistance, moldability, appearance and the like of the elastomer composition become insufficient, which is not preferable.

  The carbodiimide compound (C) used in the present invention is a compound having a structure of -N = C = N- in one molecule. Aliphatic carbodiimides, alicyclic carbodiimides, aromatic carbodiimide compounds, polymers and copolymers having these structures, and the like.

  The carbodiimide compound (C) used in the present invention is prepared, for example, by a carbon dioxide removal reaction of a diisocyanate compound. Examples of usable diisocyanates include 4,4′-diphenylmethane diisocyanate, 4,4′-diphenyldimethylmethane diisocyanate, 1,3-phenylene diisocyanate, 1,4-phenylene diisocyanate, 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate, 1,5-naphthylene diisocyanate, hexamethylene diisocyanate, dicyclohexylmethane diisocyanate, cyclohexane-1, 4-diisocyanate, xylylene diisocyanate, isophorone diisocyanate, methylcyclohexane diisocyanate, tetramethylxylylene diisocyanate 1,3,5-triisopropyl-phenylene-2,4-diisocyanate, etc. alone or two or more kinds may be used by copolymerizing. Moreover, you may introduce | transduce a branched structure or introduce | transduce functional groups other than a carbodiimide group or an isocyanate group by copolymerization. Furthermore, the degree of polymerization can be controlled and the terminal isocyanate can be blocked by blocking part or all of the terminal isocyanate. As the end-capping agent, monoisocyanate compounds such as phenyl isocyanate, tris isocyanate, dimethylphenyl isocyanate, cyclohexyl isocyanate, butyl isocyanate, naphthyl isocyanate, -OH group, -COOH group, -SH group, -NH-R (R is hydrogen) A compound having an atom or an alkyl group) can be used.

The carbodiimide compound in the present invention is preferably a polycarbodiimide compound having 2 to 50 carbodiimide groups and an isocyanate group content of 0 to 5% by mass.
The number of carbodiimide groups of the carbodiimide compound in the present invention is preferably 2 to 50 in terms of stability and handleability, more preferably 5 to 30, and further preferably 10 to 20. The carbodiimide group number is the number of carbodiimide groups in the carbodiimide molecule, and corresponds to the degree of polymerization if it is a polycarbodiimide obtained from a diisocyanate compound. For example, the polymerization degree of polycarbodiimide obtained by connecting 21 diisocyanate compounds in a chain form is 20, and the number of carbodiimide groups in the molecular chain is 20. Usually, a polycarbodiimide compound is a mixture of molecules of various lengths, and the number of carbodiimide groups is represented by an average value. The number of carbodiimide groups can be measured using a conventional method (method of dissolving in an amine solution and back titrating with hydrochloric acid: the remaining isocyanate groups react with amines and all other isocyanate groups are converted to carbodiimide groups). For the number of carbodiimide groups in the commercially available carbodiimide compound in which the terminal isocyanate group is blocked, the manufacturer's measured value may be adopted.
Since it has the number of carbodiimide groups in the above range and is solid at room temperature, it can be pulverized, so it has excellent workability and compatibility when mixed with a thermoplastic polyester elastomer, and also in terms of uniform reactivity and bleed-out resistance. preferable.
The isocyanate group content of the carbodiimide compound in the present invention is preferably 0 to 5% by mass in terms of stability and handleability, more preferably 0 to 3% by mass, and further preferably 1 to 3% by mass. In particular, it is a carbodiimide compound derived from dicyclohexylmethane diisocyanate or isophorone diisocyanate, and preferably has an isocyanate group content in the above range. The isocyanate group content represents the content (mass%) of the isocyanate group (NCO: 42 g / mol) in the carbodiimide compound, and the isocyanate group content is the same as described above (dissolved in an amine solution). It can be measured using a method of performing back titration with hydrochloric acid.

  The content of the carbodiimide compound (C) is 0.1 to 10 parts by mass with respect to a total of 100 parts by mass of the thermoplastic polyester elastomer (A) and the modified olefin elastomer (B), preferably 0.8. 5 to 5 parts by mass, more preferably 1 to 4 parts by mass. If it exceeds 10 parts by mass, flexibility may be impaired, and mechanical properties, heat resistance, and melt viscosity may be reduced. Moreover, the amount of -N = C = N- in a composition will decrease that it is less than 0.1 mass part, and it may be inferior to a hydrolysis resistance improvement effect and an extrusion property improvement effect.

  The carbodiimide compound (C) in the present invention can react with the residual hydroxyl group or carboxyl group of the thermoplastic polyester elastomer to significantly reduce the acid value. Moreover, it can also react quickly with the carboxylic acid generated by hydrolysis of the polyester elastomer, so that the acid value of the polyester elastomer composition can be kept low. Thereby, it becomes the polyester elastomer composition which has the outstanding hydrolysis resistance.

  Examples of the hindered phenol antioxidant (D) used in the elastomer composition of the present invention include 3,5-di-t-butyl-4-hydroxy-toluene and n-octadecyl-β- (4′-hydroxy-). 3 ′, 5′-di-t-butylphenyl) propionate, tetrakis [methylene-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, calcium (3,5-di-t-butyl-4-hydroxybenzyl-monoethyl-phos) Fate), triethylene glycol-bis [3- (3-t-butyl-5-methyl-4-hydroxyphenyl) propionate], 3,9-bis [1,1-dimethyl Ru-2- {β- (3-tert-butyl-4-hydroxy-5-methylphenyl) propionyloxy} ethyl] 2,4,8,10-tetraoxaspiro [5,5] undecane, bis [3, 3-bis (4′-hydroxy-3′-t-butylphenyl) butyric acid] glycol ester, 2,2′-ethylidenebis (4,6-di-t-butylphenol), N, N′-bis [3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionyl] hydrazine, 2,2′-oxamidobis [ethyl-3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionate], 1,3,5-tris (3 ′, 5′-di-t-butyl-4′-hydroxybenzyl) -S-triazine-2,4,6 (1H, 3H, 5H) -trione, 1,3 5-Tris (4- -Butyl-3-hydroxy-2,6-dimethylbenzyl) isocyanurate, 3,5-di-t-butyl-4-hydroxyhydrocinnamic ahydrtriester with-1,3,5-tris (2-hydroxy) Ethyl) -S-triazine-2,4,6 (1H, 3H, 5H), N, N′-hexamethylenebis (3,5-di-t-butyl-4-hydroxybenzenepropionamide), etc. Can do. Among these, a hindered phenol antioxidant having a molecular weight of 500 or more is preferable, and a hindered phenol antioxidant having a molecular weight of 1000 or more is more preferable. Specifically, N, N′-hexamethylenebis (3,5-di-t-butyl-4-hydroxybenzenepropionamide), tetrakis [methylene-3- (3 ′, 5′-di-t-butyl) -4'-hydroxyphenyl) propionate] methane, particularly tetrakis [methylene-3- (3 ', 5'-di-t-butyl-4'-hydroxyphenyl) propionate] methane.

  Examples of the sulfur-based antioxidant (E) used in the elastomer composition of the present invention include dilauryl-3,3′-thiodipropionic acid ester, dimyristyl-3,3′-thiodipropionic acid ester, and distearyl-3. , 3′-thiodipropionate, lauryl stearyl-3,3′-thiodipropionate, dilauryl thiodipropionate, dioctadecyl sulfide, pentaerythritol tetra (β-lauryl-thiopropionate) ) Esters can be mentioned. Of these, the use of a thiodipropion ester-based compound is particularly preferable.

The contents of the antioxidants (D) and (E) are both 0.01 to 5 parts by mass with respect to 100 parts by mass in total of the thermoplastic polyester elastomer (A) and the modified olefin elastomer (B). Preferably, it is 0.05-3 mass parts, More preferably, it is 0.1-1.5 mass parts. If the content is less than 0.01 parts by mass, it is difficult to obtain the intended effect of improving heat resistance, and if it exceeds 5 parts by mass, bleeding may occur and the appearance may deteriorate.

  It is essential that the antioxidants (D) and (E) are blended in combination, and when only one of them is blended, the intended heat resistance improving effect cannot be obtained. Although a clear reason is not known, it is estimated that not only a role as a known radical chain inhibitor and a peroxide decomposing agent but also a high heat resistance effect is exhibited by some synergistic effect.

Furthermore, in addition to the antioxidants (D) and (E), the thermoplastic polyester elastomer composition of the present invention may contain various additives depending on the purpose within a range that does not impair the effects of the present invention. A composition can be obtained. Additives include known hindered amines, triazoles, benzophenones, benzoates, nickels, salicyls and other light stabilizers, antistatic agents, lubricants, molecular weight modifiers such as peroxides, metal deactivators, Organic and inorganic nucleating agents, neutralizing agents, antacids, antibacterial agents, fluorescent brighteners, fillers, flame retardants, flame retardant aids, organic and inorganic pigments, and the like can be added.
The thermoplastic polyester elastomer composition of the present invention comprises a thermoplastic polyester elastomer (A), a modified olefin elastomer (B), a carbodiimide compound (C), a hindered phenol antioxidant (D), and a sulfur oxide. The total amount of the inhibitor (E) preferably accounts for 80% by mass or more, more preferably 90% by mass or more, and further preferably 95% by mass or more.

  As a method for producing the thermoplastic polyester elastomer composition of the present invention, the components such as the thermoplastic polyester elastomer, the modified olefin elastomer, and the carbodiimide compound in the present invention are mixed at a predetermined blending ratio and then melt-kneaded. That's fine. For mixing, a Henschel mixer, a ribbon blender, a V-type blender, or the like can be used. For melt kneading, a Banbury mixer, a kneader-type heater, a single or twin screw melt kneading extruder, or the like can be used.

The thermoplastic polyester elastomer composition of the present invention has an initial tensile elongation at break of 550 in a tensile test of a molded product (test piece) obtained from the thermoplastic polyester elastomer composition measured according to JIS K6251: 2010. %, The tensile elongation at break (%) after heat treatment at 150 ° C. for 250 hours is 70% or more, and the tensile elongation at break (%) after boiling at 100 ° C. for 350 hours is 60%. % Or more. The tensile elongation at break (elongation at break) is a value measured according to JIS K6251: 2010, and the test piece was prepared by the method described in the section of the following examples. The initial tensile elongation at break is a value measured with an untreated specimen. The heat treatment is a treatment in which the test piece is left in a hot air oven at 150 ° C. for 250 hours, and the tensile fracture elongation retention after the treatment is the retention relative to the initial tensile fracture elongation. The boiling water treatment is a treatment in which a test piece is immersed in boiling water at 100 ° C. and allowed to stand for 350 hours, and the tensile rupture elongation retention after the treatment is a retention ratio with respect to the initial tensile rupture elongation.
The thermoplastic polyester elastomer composition of the present invention can achieve these characteristics by having the configuration described above. The initial tensile breaking elongation is preferably 580% or more. The tensile fracture elongation retention after heat treatment is preferably 80% or more. The tensile elongation at break after boiling water treatment is preferably 70% or more, more preferably 80% or more, and still more preferably 90% or more.
Since heat aging resistance and water resistance can be evaluated by how much the tensile elongation at break is maintained, the tensile elongation at break is used.
Further, the initial tensile breaking strength is preferably 8 MPa or more, more preferably 10 MPa or more, and further preferably 15 MPa or more.

  The thermoplastic polyester elastomer composition of the present invention is a thermoplastic polyester elastomer composition that is flexible and excellent in heat aging resistance and water resistance, and a molded product obtained from this composition is suitable for an intake system component of an internal combustion engine. . Among internal combustion engine intake system components, it is suitable for air ducts, resonators, side branches, and air cleaners.

  Hereinafter, the present invention will be specifically described by way of examples. However, the present invention is not limited by the following examples, and can be implemented with modifications within a range that can meet the gist of the preceding and following descriptions. They are all included in the technical scope of the present invention. In addition, in this specification, each measurement followed the following method.

[Composition analysis of thermoplastic polyester elastomer]
The composition of the thermoplastic polyester elastomer was determined from its integral ratio by ¹ H-NMR analysis using a nuclear magnetic resonance analyzer (NMR) Gemini-200 manufactured by Varian in a deuterated chloroform solvent.

[Reduced viscosity of thermoplastic polyester elastomer]
0.05 g of the resin was dissolved in 25 mL of a mixed solvent (phenol / tetrachloroethane = 60/40 (mass ratio)) and measured at 30 ° C. using an Ostwald viscometer.

[Melting point (Tm) of thermoplastic polyester elastomer]
The resin dried under reduced pressure at 50 ° C. for 15 hours was measured at a heating rate of 20 ° C./min from room temperature using a differential scanning calorimeter DSC-50 (manufactured by Shimadzu Corporation), and the endothermic peak temperature due to melting was taken as the melting point. . In addition, 10 mg of a measurement sample was weighed in an aluminum pan (TA Instruments, product number 900793.901), sealed with an aluminum lid (TA Instruments, product number 900794.901), and measured in an argon atmosphere. .

[Tensile breaking strength and tensile breaking elongation]
The strength and elongation at tensile rupture of the composition were measured according to JIS K6251: 2010. The test piece was 100 mm × 100 mm at a cylinder temperature (Tm + 20 ° C.) and a mold temperature of 30 ° C. using an injection molding machine (model-SAV, manufactured by Yamashiro Seiki Co., Ltd.) after drying at 100 ° C. for 8 hours under reduced pressure. After injection molding on a flat plate of × 2 mm, a dumbbell-shaped No. 3 test piece was punched from the flat plate.

[Heat treatment: heat aging resistance test]
The dumbbell-shaped No. 3 test piece was left in a hot air oven at 150 ° C. for 250 hours and then taken out, and the tensile elongation at break was measured according to JIS K6251: 2010 as described above. The tensile fracture elongation retention was calculated and evaluated by the following formula. The initial tensile elongation at break is the tensile elongation at break before heat treatment.
Tensile elongation at break (%) = tensile elongation after heat treatment / initial tensile elongation at break × 100

[Boiling water treatment: Hydrolysis resistance test]
The above-mentioned dumbbell-shaped No. 3 test piece was immersed in 100 ° C. boiling water, allowed to stand for 350 hours and then taken out, and the tensile elongation at break was measured according to JIS K6251: 2010 as described above. The tensile fracture elongation retention was calculated and evaluated by the following formula. The initial tensile breaking elongation is the tensile breaking elongation before boiling water treatment.
Tensile elongation at break (%) = tensile elongation after boiling water treatment / initial tensile elongation at break × 100

[Extruded strand stability]
The stability of the extruded strand during melt kneading with a twin screw extruder was evaluated according to the following criteria.
(Double-circle): Strand breakage does not generate | occur | produce at all and it extrudes stably.
◯: Variation in thickness is recognized although strands are not broken.
Δ: Strand breakage sometimes occurs.
X: Strand breakage frequently occurs, and continuous take-up is difficult.

[Production of thermoplastic polyester elastomer (A-1, A-2, A-3, A-4)]
Thermoplastic polyester elastomers A-1, A-2, A-3 having the compositions shown in Table 1 using dimethyl terephthalate, 1,4-butanediol, and poly (tetramethylene oxide) glycol having a number average molecular weight of 1000 as raw materials. A-4 was synthesized. Table 1 shows the composition and various physical properties of the obtained polyester elastomer.

[Olefin-based elastomer (B)]
As the modified olefin elastomer (B-1), “Tuffmer MH5020 (maleic acid-modified ethylene / 1-butene copolymer)” manufactured by Mitsui Chemicals, Inc. was used.
In addition, “Tuffmer A4050S (ethylene / 1-butene copolymer)” manufactured by Mitsui Chemicals, Inc. was used as the unmodified olefin elastomer (B-2).

[Production of Carbodiimide Compound (C-1)]
To 262 g of 4,4′-dicyclohexylmethane diisocyanate (hereinafter also referred to as HMDI), 1.5 g of 3-methyl-1-phenyl-2-phospholene-1-oxide was added as a carbodiimidization catalyst, and nitrogen was bubbled while adding 185 The polycarbodiimide (C-1) derived from HMDI (carbodiimide group number = 16, isocyanate group content rate = 2.0 mass%) was obtained by carrying out a condensation reaction at 28 ° C. for 28 hours.

[Carbodiimide compound (C-2)]
Commercially available polycarbodiimide (“HMV-15CA” manufactured by Nisshinbo Chemical Co., Ltd .: aliphatic polycarbodiimide, carbodiimide group number = 16, isocyanate group content = 0 mass%) was used.

[Antioxidant]
Table 2 shows the abbreviations and structural formulas of the antioxidants used in the following examples.

[Examples 1-11, Comparative Examples 1-9]
Each component of the thermoplastic polyester elastomer (A), olefin elastomer (B), carbodiimide compound (C), and antioxidant was dry blended at the compounding ratios shown in Tables 3 and 4, and a 35 mmφ twin screw extruder (TOSHIBA) Machined), melt-kneaded at a temperature setting of 220 ° C. to 250 ° C., extruded into a strand, cooled with water, and pelletized with a pelletizer. The obtained pellets were dried under reduced pressure at 100 ° C. for 5 hours to obtain a thermoplastic polyester elastomer composition. The evaluation results are shown in Tables 3 and 4.

  As is apparent from the results of Tables 3 and 4, the resin component comprising the thermoplastic polyester elastomer and the modified olefin elastomer shown in Examples 1 to 11, a carbodiimide compound, a hindered phenol antioxidant, and a sulfur compound. The thermoplastic polyester elastomer composition of the present invention blended with an antioxidant is very excellent in heat aging resistance with a tensile elongation at break of 80% or more after heat treatment at 150 ° C. for 250 hours, and at 100 ° C. The tensile fracture elongation retention after 350 hours boiling water treatment is 70% or more, indicating high hydrolysis resistance. Also, good results are obtained with respect to extruded strand stability, which is an indicator of stable productivity. On the other hand, the compositions of Comparative Examples 1 to 9 that do not satisfy the conditions of the present invention are inferior in either heat aging resistance or hydrolysis resistance as compared with the compositions of the present invention.

  Comparative Example 1 in which the modified olefin elastomer is not blended, Comparative Examples 2 to 4 in which the antioxidant is blended or only one kind is blended, Comparative Example 5 in which the unmodified olefin elastomer is blended, Sulfur In Comparative Example 6 in which the antioxidant is changed to a phosphorus-based antioxidant, the tensile elongation retention after heat treatment at 150 ° C. for 250 hours is less than 70%, and the heat aging resistance is poor. . In Comparative Example 7 in which the amount of the modified olefin-based elastomer is larger than the conditions of the present invention, not only the heat aging resistance is lowered, but also the strands pulsate and cannot be stably produced. In Comparative Example 8 in which the carbodiimide compound was not blended, the tensile elongation retention after the boiling water treatment at 100 ° C. for 350 hours was less than 60%, and the hydrolysis resistance was poor. In Comparative Example 9 in which the content of the soft segment component of the polyester elastomer is larger than the conditions of the present invention, the heat aging resistance is inferior.

The thermoplastic polyester elastomer composition of the present invention is flexible and has a well-balanced balance between heat aging resistance and water resistance. It can be used suitably for the internal combustion engine intake system parts.

Claims (9)

A hard segment composed of a polyester composed of an aromatic dicarboxylic acid and an aliphatic diol or an alicyclic diol and a soft segment composed of an aliphatic polyether as main components, and the content of the soft segment is 3 to 40% by mass The total amount of 100 parts by mass of the thermoplastic polyester elastomer (A) and the modified olefin elastomer (B) is 0.1 to 10 parts by mass of a carbodiimide compound (C), a hindered phenol antioxidant ( D) 0.01 to 5 parts by mass and 0.01 to 5 parts by mass of a sulfur-based antioxidant (E) , a thermoplastic polyester elastomer (A), a modified olefinic elastomer (B), a carbodiimide compound ( C), hindered phenolic antioxidant (D), and sulfurous antioxidant (E) A thermoplastic polyester elastomer composition comprising accounted for more than 90 mass% in total, the mass ratio of the (A) wherein the (B) ((A) / (B)) is located at 95 / 5-40 / 60 The modified olefin elastomer (B) is a modified ethylene / α-olefin copolymer obtained by acid-modifying one obtained by copolymerizing ethylene and an α-olefin having 3 to 12 carbon atoms. In the tensile test measured according to JIS K6251: 2010, the initial tensile breaking elongation of the molded product obtained from the thermoplastic polyester elastomer composition is 550% or more, and the tensile strength after heat treatment at 150 ° C. for 250 hours A thermoplastic having a breaking elongation retention (%) of 70% or more and a tensile breaking elongation retention (%) after boiling water treatment at 100 ° C. for 350 hours of 60% or more. Li ester elastomer composition.   The thermoplastic polyester elastomer composition according to claim 1, wherein the hard segment which is a constituent component of the thermoplastic polyester elastomer (A) is composed of polybutylene terephthalate.   The soft segment which is a component of the thermoplastic polyester elastomer (A) is composed of poly (tetramethylene oxide) glycol (PTMG) and / or poly (propylene oxide) glycol ethylene oxide addition polymer (PPG-EO addition polymer). The thermoplastic polyester elastomer composition according to claim 1 or 2. The thermoplastic polyester elastomer composition according to any one of claims 1 to 3, wherein the modified olefin-based elastomer (B) is a maleic acid-modified ethylene / 1-butene copolymer.   The thermoplastic polyester elastomer according to any one of claims 1 to 4, wherein the carbodiimide compound (C) is a polycarbodiimide compound having 2 to 50 carbodiimide groups and an isocyanate group content of 0 to 5% by mass. Composition.   The mass ratio ((A) / (B)) of the thermoplastic polyester elastomer (A) and the modified olefin elastomer (B) is 95/5 to 65/35. 2. The thermoplastic polyester elastomer composition according to item 1.   A molded article comprising the thermoplastic polyester elastomer composition according to any one of claims 1 to 6.   The molded article according to claim 7, wherein the molded article is an internal combustion engine intake system component.   The molded article according to claim 8, wherein the internal combustion engine intake system component is any one of an air duct, a resonator, a side branch, and an air cleaner.