Thermoplastic polyester elastomer resin composition and molded object

Abstract

Provided is a thermoplastic polyester elastomer resin composition having excellent weatherability.　The thermoplastic polyester elastomer resin composition comprises (A) a thermoplastic polyester elastomer and (B) an ultraviolet absorber, a 50 μm-thick single-layer film of the thermoplastic polyester elastomer resin composition having a light transmittance ratio (380 nm / 600 nm) between 380-nm wavelength and 600-nm wavelength of less than 0.20.

Description

Thermoplastic polyester elastomer resin composition and molded article

[0001] The present invention relates to a thermoplastic polyester elastomer resin composition and a molded article using the resin composition, and more specifically relates to a thermoplastic polyester elastomer resin composition excellent in weather resistance and a molded article using the resin composition.

[0002] Thermoplastic polyester elastomers have properties such as flexibility, impact resilience, low-temperature properties and flex fatigue resistance, as well as particularly excellent heat resistance and oil resistance. Compared with other thermoplastic elastomers, thermoplastic polyester elastomers have stable mechanical properties such as tensile strength and flex fatigue resistance that do not change significantly from low temperature ranges to high temperature ranges, and are also suitable for applications that can be used in both low-temperature and high-temperature environments. Furthermore, thermoplastic polyester elastomers can be molded by various processing methods such as injection molding, extrusion molding, blow molding, compression molding and calender molding, and thus are used in a wide range of applications including automotive parts, electrical and electronic parts, fibers, sheets and films, and bottles and containers.

[0003] Although there are many molded articles using thermoplastic polyester elastomer resin compositions, they are used in various environments such as being directly exposed to sunlight, rain and wind, so there has been a demand for them not to suffer deterioration of physical properties in such environments. For example, Patent Document 1 discloses a thermoplastic polyester elastomer resin composition comprising a thermoplastic polyester elastomer, a thickener, an ultraviolet absorber and a light stabilizer. Patent Document 2 discloses a thermoplastic polyester elastomer resin composition comprising a thermoplastic polyester elastomer, a phosphorus-based flame retardant, and a hindered amine-based radical scavenger. Patent Document 3 discloses a thermoplastic polyester elastomer resin composition comprising a thermoplastic polyester elastomer, a hindered phenol-based compound, a phosphite-based compound, and a benzotriazole-based compound having an imide group.

[0004] International Publication No. 2019 / 004120 Pamphlet, International Publication No. 2018 / 155411 Pamphlet, Japanese Unexamined Patent Publication No. Hei 7-179737

[0005] Resin products are known to deteriorate over time due to external factors such as sunlight, especially ultraviolet rays, when used in outdoor environments. In particular, a decrease in the "elongation" properties of the resin leads to hardening and brittleness of the product, causing breakage and malfunction. Therefore, improvement has been required from the perspective of ensuring long-term durability.

[0006] The object of the present invention is to provide a thermoplastic polyester elastomer resin composition that has excellent weather resistance, capable of suppressing the deterioration of mechanical properties, particularly elongation properties, even when exposed to light including ultraviolet rays for a long period of time.

[0007] The present invention, which has solved the above problems, has the following configuration: [1] A thermoplastic polyester elastomer resin composition comprising (A) a thermoplastic polyester elastomer and (B) an ultraviolet absorber, wherein the light transmittance ratio (380 nm / 600 nm) at wavelengths of 380 nm and 600 nm in a single layer film of the thermoplastic polyester elastomer resin composition with a thickness of 50 μm is less than 0.20. [2] The thermoplastic polyester elastomer resin composition according to [1], wherein the (B) ultraviolet absorber, in a solution dissolved in chloroform at a concentration of 10 mg / L, has a total absorbance value of 3.0 or more at each integer wavelength in the range of 370 to 400 nm. [3] The thermoplastic polyester elastomer resin composition according to [1] or [2], comprising less than 3.0 parts by mass of the (B) ultraviolet absorber per 100 parts by mass of the (A) thermoplastic polyester elastomer. [4] The thermoplastic polyester elastomer resin composition according to any one of [1] to [3], wherein the (A) thermoplastic polyester elastomer is a copolymer of a hard segment and a soft segment, and the hard segment comprises an aromatic dicarboxylic acid or an ester-forming derivative thereof and a diol or an ester-forming derivative thereof. [5] The thermoplastic polyester elastomer resin composition according to [4], wherein the hard segment is a constituent unit derived from butylene terephthalate and / or a constituent unit derived from butylene naphthalate. [6] The thermoplastic polyester elastomer resin composition according to [4], wherein the soft segment is at least one selected from the group consisting of aliphatic polyether, aliphatic polyester, and aliphatic polycarbonate. [7] The thermoplastic polyester elastomer resin composition according to [6], wherein the soft segment is poly(tetramethylene oxide) glycol. [8] The thermoplastic polyester elastomer resin composition according to any one of [1] to [7], wherein the (B) ultraviolet absorber is at least one selected from the group consisting of benzophenone-based ultraviolet absorbers, benzotriazole-based ultraviolet absorbers, and triazine-based ultraviolet absorbers.[9] A molded article comprising the thermoplastic polyester elastomer resin composition described in any of [1] to [8].

[0008] According to the present invention, a thermoplastic polyester elastomer resin composition with excellent weather resistance can be provided that can suppress the deterioration of mechanical properties, particularly elongation properties, even when exposed to light including ultraviolet rays. Furthermore, due to the above effect, molded articles using the resin composition of the present invention can suppress the deterioration of mechanical properties, particularly elongation properties, even when exposed to light including ultraviolet rays.

[0009] The thermoplastic polyester elastomer resin composition of this disclosure (hereinafter sometimes simply referred to as "resin composition") comprises (A) a thermoplastic polyester elastomer and (B) an ultraviolet absorber, wherein the light transmittance ratio (380 nm / 600 nm) at wavelengths of 380 nm and 600 nm in a 50 μm thick single-layer film of the resin composition is less than 0.20. In a preferred embodiment, the sum of the absorbances at each integer wavelength in the range of 370 to 400 nm (hereinafter sometimes referred to as absorbance at wavelengths of 370 to 400 nm) in a solution obtained by dissolving (B) the ultraviolet absorber in chloroform at a concentration of 10 mg / L is 3.0 or higher. In this disclosure, weather resistance means durability under environmental conditions including ultraviolet light, and specifically may refer to the performance of maintaining mechanical properties. Mechanical properties refer to the half-time of elongation in tensile elongation at break (hereinafter sometimes referred to as elongation), and in this disclosure, weather resistance is evaluated based on the elongation half-time. In one embodiment, the mechanical properties may include, in addition to elongation, one or more of tensile strength, bending fatigue resistance, and fatigue properties. Hydrolysis resistance may also be included in addition to the above.

[0010] In this disclosure, the reason why the light transmittance ratio for a 50 μm thick single-layer film of the resin composition is set to the light transmittance at a wavelength of 380 nm relative to the light transmittance at a wavelength of 600 nm (380 nm / 600 nm) is as follows: In order to suppress the deterioration of the mechanical properties of the resin composition, it is necessary to improve the weather resistance to light, especially ultraviolet light. However, general ultraviolet absorbers may not provide sufficient weather resistance. For example, ultraviolet absorbers whose ultraviolet absorption peaks are in the short-wavelength ultraviolet region (UV-C: 290 nm or less) or the medium-wavelength ultraviolet region (UV-B: 290 to 320 nm) cannot sufficiently absorb ultraviolet light around 380 nm, and therefore cannot suppress the photodegradation of the resin composition. Furthermore, even with ultraviolet absorbers corresponding to the long-wavelength region (UV-A: 320 to 400 nm), the ultraviolet absorption peak is in the 340 to 360 nm region, so they cannot sufficiently absorb ultraviolet light around 380 nm, and therefore cannot provide sufficient weather resistance. For this reason, this disclosure focuses on the wavelength of 380 nm, which is particularly difficult to block among ultraviolet rays. Furthermore, ultraviolet light around 380 nm belongs to the longer wavelength range of UV-A, and is thought to penetrate deeper into molded products, causing cumulative photodegradation and affecting the long-term durability of mechanical properties. Therefore, blocking ultraviolet light around 380 nm with an ultraviolet absorber is considered an important point in suppressing photodegradation of thermoplastic polyester elastomer resin compositions. The reason for using 600 nm as the reference wavelength is that it is a wavelength that is less affected by the basic structure of thermoplastic polyester elastomer (types and ratios of hard and soft segments, etc.).

[0011] Furthermore, the resin composition of this disclosure has a light transmittance ratio (380 nm / 600 nm) of less than 0.20 at wavelengths of 380 nm and 600 nm in a single layer film with a thickness of 50 μm. If the above is not met, for example, if the light transmittance ratio (380 nm / 600 nm) is 0.20 or higher, the resin composition may deteriorate due to light (especially ultraviolet light), i.e., it may become more susceptible to yellowing (discoloration), and its mechanical properties, particularly its elongation properties, may decrease. When mechanical properties decrease, even if external forces are applied within a range that would not cause problems with the original mechanical properties of the resin composition, it may lead to product damage. In particular, the durability performance during repeated fatigue may decrease, and the service life may decrease. The light transmittance ratio (380 nm / 600 nm) is less than 0.20, preferably 0.15 or less, more preferably 0.10 or less, even more preferably 0.05 or less, and even more preferably 0.01 or less.

[0012] In a preferred embodiment of this disclosure, the ultraviolet absorber contained in the resin composition has a total absorbance of 3.0 or more at wavelengths of 370 to 400 nm in a solution dissolved in chloroform at a concentration of 10 mg / L. In order to suppress the deterioration of the mechanical properties of the resin composition, it is necessary to improve the light resistance to light, especially ultraviolet light. The carbon-oxygen bonds contained in the ester bonds of thermoplastic polyester elastomers are easily broken by light with wavelengths around 370 nm. Furthermore, in one embodiment, the inventors found that, considering the penetration of ultraviolet light into thick resins, wavelengths of 370 nm and above, which are on the longer wavelength side, easily reach the inside of the resin and have a large impact on the mechanical properties. On the other hand, considering the elongation properties, the ultraviolet absorber does not need to absorb much light with wavelengths exceeding 400 nm. Therefore, the effective absorption wavelength range of the ultraviolet absorber was set to 370 to 400 nm. The total absorbance at wavelengths of 370 to 400 nm is preferably 3.0 or more, more preferably 5.0 or more, and even more preferably 7.0 or more.

[0013] In one embodiment, in a 50 μm thick single-layer film of the resin composition, in addition to setting the light transmittance ratio (380 nm / 600 nm) to less than 0.20, adding an ultraviolet absorber to the resin composition that exhibits a total absorbance of 3.0 or more at wavelengths of 370 to 400 nm makes it possible to more effectively suppress the deterioration of elongation characteristics due to ultraviolet light.

[0014] In one embodiment, in a solution in which the ultraviolet absorber is dissolved in the above-mentioned chloroform, the sum of the absorbances at each integer value in the wavelength range of 305 to 315 nm (hereinafter sometimes referred to as the absorbance at wavelengths of 305 to 315 nm) and the sum of the absorbances at wavelengths of 370 to 400 nm is preferably 10.0 or higher, more preferably 12.0 or higher, and even more preferably 14.0 or higher, from the viewpoint of suppressing photodegradation of the thermoplastic polyester elastomer. Since thermoplastic polyester elastomers have a high absorption wavelength around 310 nm, there is a possibility that the molecular weight will decrease due to light irradiation in this wavelength range, and by specifying the absorbance together with the absorbance at wavelengths of 370 to 400 nm, the photodegradation of the thermoplastic polyester elastomer can be further suppressed. Molded articles using the resin composition of this disclosure have excellent elongation. In one embodiment, in addition to elongation, molded articles using the resin composition of this disclosure have excellent properties such as tensile strength, flexibility, rebound elasticity, bending fatigue resistance, moisture and heat resistance, and oil resistance.

[0015] In preferred embodiments of this disclosure, the light transmittance of the resin composition (a single-layer film with a thickness of 50 μm) at a wavelength of 380 nm is preferably 20% or less, more preferably 15% or less, and even more preferably 13% or less. A lower light transmittance at 380 nm is preferable because it suppresses the deterioration of the mechanical properties of the resin composition.

[0016] In a preferred embodiment of the present disclosure, the light transmittance of the above resin composition (a single-layer film with a thickness of 50 μm) at a wavelength of 600 nm is 95% or less, preferably 93% or less. In particular, even if the light transmittance at a wavelength of 600 nm exceeds 90%, a resin composition satisfying the above configuration can suppress a decrease in mechanical properties.

[0017] The acid value of the resin composition used in this disclosure is preferably 80 eq / ton or less, more preferably 60 eq / ton or less, even more preferably 50 eq / ton or less, even more preferably 20 eq / ton or less, and most preferably 0 eq / ton.

[0018] [Thermoplastic Polyester Elastomer] The thermoplastic polyester elastomer of this disclosure is a copolymer of a hard segment and a soft segment. The bond between the hard segment and the soft segment may be achieved by a chain extender such as an isocyanate compound, or the constituent units of the hard segment and the soft segment may be directly bonded by ester bonds and / or carbonate bonds.

[0019] The hard segment is made of polyester, and the polyester is composed of an aromatic dicarboxylic acid or its ester-forming derivative (sometimes called an acid component) and a diol or its ester-forming derivative (sometimes called a diol component). As the aromatic dicarboxylic acid, at least one selected from the group consisting of terephthalic acid and naphthalenedicarboxylic acid is preferred. Furthermore, 2,6-naphthalenedicarboxylic acid is preferred. As the ester-forming derivative, for example, dimethyl terephthalate, which is a dimethyl ester of terephthalic acid, is an example. Other dicarboxylic acids other than the above aromatic dicarboxylic acid (other acid components) may also be included. Examples of other acid components include aromatic dicarboxylic acids other than terephthalic acid and naphthalenedicarboxylic acid (other aromatic dicarboxylic acids), aliphatic dicarboxylic acids, and alicyclic dicarboxylic acids. Examples of other aromatic dicarboxylic acids include diphenyldicarboxylic acid, isophthalic acid, and 5-sodium sulfisoisophthalic acid. Examples of aliphatic dicarboxylic acids include succinic acid, glutaric acid, adipic acid, azelaic acid, sebacic acid, and dodecanedioic acid. Examples of alicyclic dicarboxylic acids include cyclohexanedicarboxylic acid and tetrahydrophthalic anhydride.

[0020] The total amount of terephthalic acid and / or naphthalenedicarboxylic acid in the total dicarboxylic acids constituting the hard segment is preferably 60 mol% or more, more preferably 65 mol% or more, even more preferably 70 mol% or more, and may be 100 mol%. The remainder may consist of the other acidic components mentioned above.

[0021] The diol component constituting the hard segment is preferably a glycol, more preferably an aliphatic diol and / or an alicyclic diol. The aliphatic diol is not particularly limited, but is preferably an alkylene glycol having 2 to 8 carbon atoms. Suitable examples of aliphatic diols include ethylene glycol, 1,3-propanediol, 1,4-butanediol, 1,5-pentanediol, and 1,6-hexanediol. A suitable example of an alicyclic diol is 1,4-cyclohexanedimethanol. These diol components may be used individually or in combination of two or more, with 1,4-butanediol being more preferred.

[0022] In one embodiment, the constituent units of the polyester are preferably butylene terephthalate-derived units (derived from terephthalic acid and 1,4-butanediol) and / or butylene naphthalate-derived units (derived from 2,6-naphthalenedicarboxylic acid and 1,4-butanediol), with butylene terephthalate-derived units being preferred. These constituent units are effective in improving the physical properties and moldability of the thermoplastic polyester elastomer resin composition and are also preferred from the viewpoint of cost performance.

[0023] The soft segment is a component that gives flexibility to the elastomer, and is preferably at least one selected from the group consisting of aliphatic polyethers, aliphatic polyesters, and aliphatic polycarbonates, and is preferably an aliphatic polyether. The compounds exemplified below may be used alone or in combination of two or more.

[0024] Examples of aliphatic polyethers include poly(ethylene oxide) glycol, poly(propylene oxide) glycol, poly(trimethylene oxide) glycol, poly(tetramethylene oxide) glycol, poly(hexamethylene oxide) glycol, copolymers of ethylene oxide and propylene oxide, ethylene oxide adducts of poly(propylene oxide) glycol, and copolymers of ethylene oxide and tetrahydrofuran. Among these, poly(tetramethylene oxide) glycol and ethylene oxide adducts of poly(propylene oxide) glycol are preferred when considering flexibility, long-term durability such as long-term heat aging resistance, hydrolysis resistance, and flexural fatigue resistance, and chemical stability.

[0025] Examples of aliphatic polyesters include poly(ε-caprolactone), polyenanthractone, polycapryloractone, and polybutylene adipate. Among these, poly(ε-caprolactone) and polybutylene adipate are preferred when considering flexibility, durability, and chemical stability.

[0026] The aliphatic polycarbonate is preferably composed of aliphatic diol residues having 2 to 12 carbon atoms. Examples include ethylene glycol, 1,3-propanediol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 1,8-octanediol, 2,2-dimethyl-1,3-propanediol, 3-methyl-1,5-pentanediol, 2,4-diethyl-1,5-pentanediol, 1,9-nonanediol, and 2-methyl-1,8-octanediol. Among these, aliphatic diols having 5 to 12 carbon atoms are preferred considering the flexibility, durability, and chemical stability of the thermoplastic polyester elastomer.

[0027] In this disclosure, it is also preferable to select the soft segment considering low-temperature properties. For example, as an aliphatic polycarbonate diol with good low-temperature properties that constitutes the soft segment, it is preferable to have a low melting point (e.g., 70°C or lower) and a low glass transition temperature (e.g., around -70°C). For example, an aliphatic polycarbonate diol made of 1,6-hexanediol has a low glass transition temperature of around -60°C and a melting point of around 50°C, so it has good low-temperature properties. In addition, an aliphatic polycarbonate diol obtained by copolymerizing an appropriate amount of, for example, 3-methyl-1,5-pentanediol with an aliphatic polycarbonate diol has a slightly higher glass transition temperature than the original aliphatic polycarbonate diol, but its melting point is lower or it becomes amorphous, so it corresponds to an aliphatic polycarbonate diol with good low-temperature properties. For example, an aliphatic polycarbonate diol composed of 1,9-nonanediol and 2-methyl-1,8-octanediol has a sufficiently low melting point of around 30°C and a glass transition temperature of around -70°C, making it an aliphatic polycarbonate diol with good low-temperature properties.

[0028] Considering weather resistance, the thermoplastic polyester elastomer used in this disclosure is preferably a copolymer mainly composed of terephthalic acid, 1,4-butanediol, and poly(tetramethylene oxide) glycol. In one embodiment, the main component is 50% by mass or more, more preferably 70% by mass or more, even more preferably 90% by mass or more, and even more preferably 100% by mass, of 100% by mass of the resin composition constituting the thermoplastic polyester elastomer. In one embodiment, the content of terephthalic acid in the dicarboxylic acid component constituting the thermoplastic polyester elastomer is preferably 40 mol% or more, more preferably 70 mol% or more, even more preferably 80 mol% or more, and particularly preferably 90 mol% or more. Also, the total of 1,4-butanediol and poly(tetramethylene oxide) glycol in the glycol component constituting the thermoplastic polyester elastomer is preferably 40 mol% or more, more preferably 70 mol% or more, even more preferably 80 mol% or more, and particularly preferably 90 mol% or more.

[0029] In one embodiment, the number average molecular weight of at least one selected from the group consisting of aliphatic polyethers, aliphatic polyesters, and aliphatic polycarbonates constituting the soft segment, preferably poly(tetramethylene oxide) glycol, is preferably 500 to 4000, more preferably 600 to 3000, and even more preferably 800 to 2500. If the number average molecular weight is too small, it is difficult to exhibit elastomer properties, and if the number average molecular weight is too large, the compatibility with the hard segment component decreases, which may make copolymerization into a block-like structure difficult, for example.

[0030] In one embodiment, the thermoplastic polyester elastomer of the present disclosure preferably does not contain either or both of the constituent units derived from 1,4-cyclohexanedimethanol and the constituent units derived from hydrogenated dimer ol, and more preferably does not contain both the constituent units derived from 1,4-cyclohexanedimethanol and the constituent units derived from hydrogenated dimer ol.

[0031] In thermoplastic polyester elastomers, the mass ratio of hard segments to soft segments (hard segments:soft segments) is preferably 10:90 to 95:5, more preferably 15:85 to 90:10, even more preferably 20:80 to 85:15, and most preferably 25:75 to 75:25. If the soft segment ratio is too low, flexibility, elasticity, impact resistance, or processability may be insufficient. On the other hand, if the soft segment ratio is excessively high, heat resistance and abrasion resistance may decrease. Particularly considering the balance between tensile strength and flexural fatigue after weathering tests, the mass ratio (hard segments:soft segments) is even more preferably 20:80 to 85:15, and most preferably 25:75 to 75:25. If there are too few hard segments, heat resistance may be insufficient, and tensile strength may decrease, especially after weathering tests. On the other hand, if there are too many hard segments, flexibility may decrease, and flexural fatigue may worsen, especially after weathering tests. In one embodiment, for applications where heat resistance and wear resistance are particularly required, the mass ratio (hard segment:soft segment) may be preferably 50:50 to 95:5, and more preferably 50:50 to 60:40.

[0032] The reduced viscosity of thermoplastic polyester elastomer is preferably 0.5 to 4.0 dL / g, more preferably 1.0 to 3.5 dL / g, considering fluidity, moldability, heat aging resistance, hydrolysis resistance, mechanical properties, and chemical resistance. The reduced viscosity is measured using, for example, phenol / tetrachloroethane = 60 / 40 as the solvent at a concentration of 0.23 g / dL at 30°C.

[0033] Ultraviolet absorbers are effective in preventing photodegradation caused by ultraviolet light. An ultraviolet absorber is a substance that has the ability to absorb in the ultraviolet region (UVA: 320-400 nm, UVB: 280-320 nm, UVC: 200-280 nm), preferably an ultraviolet absorber whose ultraviolet absorption spectrum peak is in the UVA region, and more preferably an ultraviolet absorber that has the effect of reducing the transmittance of ultraviolet light around a wavelength of 380 nm. Furthermore, it is also preferable to use an ultraviolet absorber in which the absorbance of a solution obtained by dissolving the ultraviolet absorber in chloroform at a concentration of 10 mg / L is 3.0 or higher when the sum of the absorbances at each integer wavelength in the range of 370-400 nm is 3.0 or higher. Examples of UV absorbers include benzophenone-based UV absorbers, benzotriazole-based UV absorbers, triazine-based UV absorbers, cyanoacrylate-based UV absorbers, salicylate-based UV absorbers, oxanilide-based UV absorbers, and nickel-based UV absorbers. Of these, the UV absorber must satisfy the above-mentioned transmittance reduction effect, preferably absorbance. Among these, considering the stability of the resin composition at processing temperatures and compatibility with the resin, at least one selected from the group consisting of benzophenone-based UV absorbers, benzotriazole-based UV absorbers, and triazine-based UV absorbers is preferred, as it satisfies the above-mentioned transmittance reduction effect, preferably absorbance.

[0034] Examples of benzophenone-based UV absorbers include 2,2'-dihydroxy-4-methoxybenzophenone.

[0035] Examples of benzotriazole-based ultraviolet absorbers include 2-(5-chloro-2-benzotriazol)-6-tert-butyl-p-cresol and 2,2'-methylenebis[6-(benzotriazol-2-yl)-4-tert-octylphenol].

[0036] Examples of triazine-based UV absorbers include 6,6',6''-(1,3,5-triazine-2,4,6-triyl)tris[3-(hexyloxy)-2-methylphenol].

[0037] In addition to the above, it is also possible to use various known ultraviolet absorbers (including commercially available products) that satisfy the above requirements of this disclosure. The ultraviolet absorbers may be used alone or in combination of two or more types, and for example, using ultraviolet absorbers having different absorption spectra is one preferred embodiment.

[0038] The total content of the ultraviolet absorber is preferably less than 3.0 parts by mass (excluding 0 parts by mass) per 100 parts by mass of thermoplastic polyester elastomer, more preferably 0.1 parts by mass or more and 2.5 parts by mass or less, even more preferably 0.3 parts by mass or more and 2.0 parts by mass or less, with an even more preferable upper limit of 1.0 part by mass or less. The content of the ultraviolet absorber is sufficient to obtain the effects of this disclosure, and there is no particular lower limit, however, if the content of the ultraviolet absorber is too high, bleed-out may occur, which may cause contamination of the machine during manufacturing, poor appearance, and reduced weather resistance.

[0039] In one embodiment, it is also preferable to adjust the molecular weight of the ultraviolet absorber, more preferably 200 or more. If the molecular weight is too low, bleed-out may occur, which can cause poor appearance and reduced effectiveness of the resin composition (especially molded articles using the resin composition). If the molecular weight is too high, the compatibility with the resin may decrease, potentially reducing the mechanical properties, so it is preferably 1,000 or less, more preferably 800 or less. In one embodiment, it is also preferable that the ultraviolet absorber has a predetermined melting point, and considering the handling during processing of the resin composition and molded articles, the melting point is preferably 50°C or higher, more preferably 60°C or higher, and even more preferably 100°C or higher.

[0040] The total content of thermoplastic polyester elastomer and ultraviolet absorber in the resin composition is preferably 80% by mass or more, more preferably 85% by mass or more, and even more preferably 90% by mass or more, and may be 100% by mass, based on 100% by mass of the resin composition. The resin composition may also contain various additives described below as the remainder of the above content, to the extent that it does not impair the effects of the present disclosure.

[0041] Terminal Acid Value In one embodiment, in order to suppress long-term durability, particularly a decrease in mechanical properties due to hydrolysis, it is also preferable that the resin composition of the present disclosure keeps the terminal acid value low. The acid value of the resin composition of the present disclosure is preferably 80 eq / ton or less, more preferably 60 eq / ton or less, still more preferably 20 eq / ton or less, and the lower limit may be 0 eq / ton, or may be more than 0 eq / ton. The smaller the acid value, the more effective it is in improving hydrolysis resistance. Furthermore, a small acid value is preferable because mechanical properties such as strength can be maintained over a long period of time. The acid value described in the present disclosure is a value measured by the method described in the Examples.

[0042] Light Stabilizer In one embodiment, the resin composition of the present disclosure may comprise a light stabilizer. Although ultraviolet absorbers and light stabilizers have different mechanisms of action, they are effective in preventing photodegradation. Furthermore, when both are used in combination, a synergistic effect enables superior weather resistance (degradation resistance against external environments such as sunlight, rain, and temperature changes) to be maintained over a long period of time. A light stabilizer is a substance having an ability to scavenge free radicals generated in a resin, and is preferable because it can suppress degradation of the resin caused by photoexcitation reactions over a long period of time. As the light stabilizer, a hindered amine light stabilizer (HALS) is preferable. Further, the hindered amine light stabilizer is a tertiary amine type (N-CH ３ ) or any of a low basic type such as an N-alkoxy type (NO-Alkyl) and a high basic type of a secondary amine type (N-H). In one embodiment, since low basic type HALS has low basicity, it is less susceptible to the influence (deactivation) caused by acidic substances that may be present in the resin, and may exhibit stable performance over a long period of time. Furthermore, from the viewpoint of suppressing adverse effects on the resin, a non-basic light stabilizer may be used. In addition, high basic type HALS may exhibit a high stabilizing effect for specific resin systems. Therefore, it can be selected according to the type of resin and usage conditions. Specific examples are shown below, but they may be used alone or in combination of two or more, and HALS may be a commercially available product.

[0043] Specific examples of low-basic HALS include 2,2,6,6-tetramethyl-4-piperidyl stearate, 1,2,2,6,6-pentamethyl-4-piperidyl stearate, 2,2,6,6-tetramethyl-4-piperidyl benzoate, bis(2,2,6,6-tetramethyl-4-piperidyl) sebacate, bis(1,2,2,6,6-pentamethyl-4-piperidyl) sebacate, bis(1-octoxy-2,2,6,6-tetramethyl-4-piperidyl) sebacate, tetrakis(2,2,6,6-tetramethyl-4-piperidyl)-1,2,3,4-butanetetracarboxylate, and tetrakis(1,2,2,6,6-pe Examples include bis(2,2,6,6-tetramethyl-4-piperidyl)-1,2,3,4-butanetetracarboxylate, bis(1,2,2,6,6-pentamethyl-4-piperidyl)-di(tridecyl)-1,2,3,4-butanetetracarboxylate, bis(1,2,2,6,6-pentamethyl-4-piperidyl)-di(tridecyl)-1,2,3,4-butanetetracarboxylate, bis(1,2,2,4,4-pentamethyl-4-piperidyl)-2-butyl-2-(3,5-di-t-butyl-4-hydroxybenzyl)malonate, and 1-(2-hydroxyethyl)-2,2,6,6-tetramethyl-4-piperidinol / diethyl succinate polycondensate.Specific examples of highly basic HALS include 1,6-bis(2,2,6,6-tetramethyl-4-piperidylamino)hexane / 2,4-dichloro-6-morpholino-s-triazine polycondensate, 1,6-bis(2,2,6,6-tetramethyl-4-piperidylamino)hexane / 2,4-dichloro-6-tertioctylamino-s-triazine polycondensate, 1,5,8,12-tetrakis[2,4-bis(N-butyl-N-(2,2,6,6-tetramethyl-4-piperidyl)amino)-s-triazine-6-yl]-1,5,8,12-tetraazadodecane, 1,5, Examples include 8,12-tetrakis[2,4-bis(N-butyl-N-(1,2,2,6,6-pentamethyl-4-piperidyl)amino)-s-triazine-6-yl]-1,5,8,12-tetraazadodecane, 1,6,11-tris[2,4-bis(N-butyl-N-(2,2,6,6-tetramethyl-4-piperidyl)amino)-s-triazine-6-yl]aminoundecane, and 1,6,11-tris[2,4-bis(N-butyl-N-(1,2,2,6,6-pentamethyl-4-piperidyl)amino)-s-triazine-6-yl]aminoundecane.

[0044] The total content of the light stabilizer is preferably 0.1 to 4.0 parts by mass, more preferably 0.2 to 3.5 parts by mass, and even more preferably 0.3 to 3.0 parts by mass, per 100 parts by mass of thermoplastic polyester elastomer, with an even more preferable upper limit of 1.0 part by mass or less. If the content of the light stabilizer is too high, problems may arise due to bleed-out, such as the light stabilizer rising to the surface of the resin composition and causing mold contamination and other machine base contamination.

[0045] Light-shielding agent In one embodiment, the resin composition of the present disclosure may contain a light-shielding agent. In the present disclosure, a light-shielding agent is a substance that has the property of reflecting light on its surface (sometimes called light reflectivity) and / or absorbing and dissipating light within the substance (sometimes called light absorption). A light-reflective light-shielding agent may have the property of absorbing light of a specific wavelength in addition to reflecting light. A light-absorbing light-shielding agent may have the property of reflecting light of a specific wavelength in addition to absorbing light. As a result of the inventors' studies, it has been found that when a light-shielding agent having the above properties is included in the resin composition, a light-shielding effect is obtained not only in the short-wavelength and medium-wavelength ultraviolet regions but also in the long-wavelength region, and in particular, the photodegradation of the resin composition by ultraviolet light at a wavelength of 380 nm can be suppressed, and it is also effective for wavelengths other than ultraviolet light. Because light is blocked by the light-shielding agent contained in the resin composition, the photodegradation of the resin composition by light (especially ultraviolet light, the same applies hereinafter) can be suppressed. It is preferable to use an inorganic material as the light-shielding agent. A typical example of an absorbent light-shielding agent is carbon black, which is particularly preferred because it exhibits excellent dispersibility in resins. Typical examples of light-reflecting light-shielding agents include magnesium oxide, aluminum oxide, silicon oxide, calcium oxide, titanium oxide (rutile type, anatase type), chromium oxide (trivalent), iron oxide, zinc oxide, silica, diatomaceous earth, barium ferrite, strontium ferrite, beryllium oxide, magnesium hydroxide, aluminum hydroxide, basic or hydroxide compounds of magnesium carbonate, or magnesium carbonate, calcium carbonate, barium carbonate, calcium sulfite, dolomite, dawsonite carbonate, and calcium sulfate. Preferred light shielding agents include ()sulfites such as barium sulfate, calcium sulfite, and basic magnesium sulfate, sodium silicate, magnesium silicate, aluminum silicate, potassium silicate, calcium silicate, talc, clay, mica, montmorillonite, glass balloons, glass beads, bentonite silicates, kaolin (clay), perlite, molybdenum sulfide, potassium titanate, lead zirconate titanate, zinc borate, aluminum borate, barium metaborate, calcium borate, sodium borate, etc., with zinc oxide being more preferred. One or more light shielding agents may be used in combination.The light shielding agent may be appropriately selected depending on the application, effect, etc. However, since a light shielding agent formed of metal itself may cause resin deterioration, it is preferable to use an inorganic material such as a stable oxide or carbonate, or a non-metallic material such as carbon black. In the present disclosure, either one of a light-reflective light shielding agent and a light-absorbing light shielding agent may be used, or both may be used in combination.

[0046] In one embodiment, the content of the light shielding agent in the resin composition is preferably adjusted in consideration of the light transmittance ratio (380 nm / 600 nm). For example, the content of the light-absorbing light shielding agent in the resin composition is preferably 0.1 to 20 parts by mass, more preferably 0.2 to 15 parts by mass, still more preferably 0.25 to 12 parts by mass, particularly preferably 0.3 to 10 parts by mass, relative to 100 parts by mass of the thermoplastic polyester elastomer. In consideration of higher dispersibility and bending fatigue resistance, the upper limit is preferably less than 10 parts by mass, more preferably 6 parts by mass or less, particularly preferably 2 parts by mass or less. Further, for example, the content of the light-reflective light shielding agent in the resin composition is preferably 0.1 to 20 parts by mass, more preferably 0.1 to 15 parts by mass, still more preferably 0.25 to 12 parts by mass, particularly preferably 0.3 to 10 parts by mass, relative to 100 parts by mass of the thermoplastic polyester elastomer. Excessive content may cause poor dispersion, poor filling, and further decomposition of the resin composition and reduction in bending fatigue resistance.

[0047] If necessary, the resin composition may contain known additives other than those described above as other additives. Examples of other additives include stabilizers such as antioxidants, thickeners, coupling agents, light shielding agents (pigments) other than those described above, antibacterial agents, fluorescent brighteners, flame retardants, flame retardant auxiliaries, tack improvers, quenchers, antistatic agents, lubricants, and metal deactivators. One or two or more other additives can be used in combination as needed.

[0048] Antioxidant is preferably added to suppress oxidative deterioration during thermoforming or use of the product. General-purpose types such as hindered phenol-based, phosphorus-based, sulfur-based, and aromatic amine-based antioxidants can be used as the antioxidant.

[0049] In one embodiment, the thickener is effective in adjusting the viscosity and end acid value of thermoplastic polyester elastomers (especially resin compositions). The type and amount of thickener added can be adjusted, for example, according to the molding method, to achieve the desired viscosity and acid value. For example, the reduced viscosity of the resin composition is preferably 0.5 to 4.0 dL / g, more preferably 1.0 to 3.8 dL / g, and even more preferably 1.2 to 3.5 dL / g. Considering the balance between the acid value and physical properties such as moldability during manufacturing and the flexural fatigue resistance of the resin composition (and molded article), the content of the thickener is preferably 7 parts by mass or less, more preferably 5 parts by mass or less, and even more preferably 4 parts by mass or less, per 100 parts by mass of thermoplastic polyester elastomer. If the content is too high, the thickening effect will be excessive, which may adversely affect moldability and the mechanical properties of the molded article, or cause mold contamination. If the end acid value is 25 eq / ton or less, a thickener may not be used, but if a thickener is used to adjust the end acid value, it is preferable to adjust the amount added as appropriate.

[0050] The thickening agent is preferably a reactive compound that can react with the terminal groups of the thermoplastic polyester elastomer, such as hydroxyl groups, and more preferably a carbodiimide compound and / or an epoxy compound.

[0051] Carbodiimide compounds are compounds having at least one, preferably two or more, carbodiimide groups (-N=C=N-) in one molecule, with polymeric polycarbodiimides being particularly preferred. In one embodiment, from the viewpoint of weather resistance and compatibility, examples include aliphatic polycarbodiimides, alicyclic polycarbodiimides, aromatic polycarbodiimides, and copolymers thereof. Preferably, they are aliphatic polycarbodiimide compounds or alicyclic polycarbodiimide compounds.

[0052] Monocarbodiimide compounds: diphenylcarbodiimide, dicyclohexylcarbodiimide, di-2,6-dimethylphenylcarbodiimide, diisopropylcarbodiimide, dioctyldecylcarbodiimide, di-o-toluylcarbodiimide, di-p-toluylcarbodiimide, di-p-nitrophenylcarbodiimide, di-p-aminophenylcarbodiimide, di-p-hydroxyphenylcarbodiimide, di-p-chlorophenylcarbodiimide, di-o-chlorophenylcarbodiimide, di-3,4-dichlorophenylcarbodiimide, di-2,5-dichlorophenylcarbodiimide, p-phenylene-bis-o-toluylcarbodiimide;

[0053] Dicarbodiimide compounds: p-phenylene-bis-dicyclohexylcarbodiimide, p-phenylene-bis-di-p-chlorophenylcarbodiimide, 2,6,2',6'-tetraisopropyldiphenylcarbodiimide, hexamethylene-bis-cyclohexylcarbodiimide, ethylene-bis-diphenylcarbodiimide, ethylene-bis-dicyclohexylcarbodiimide, N,N'-di-o-toluylcarbodiimide, N,N'-diphenylcarbodiimide, N,N'-dioctyldecylcarbodiimide, N,N'-di-2,6-dimethyl N,N'-Toluyl-N'-Cyclohexylcarbodiimide, N,N'-Di-2,6-Diisopropylphenylcarbodiimide, N,N'-Di-2,6-Di-Tert-Butylphenylcarbodiimide, N,N'-Toluyl-N'-Phenylcarbodiimide, N,N'-Di-p-Nitrophenylcarbodiimide, N,N'-Di-p-Aminophenylcarbodiimide, N,N'-Di-p-Hydroxyphenylcarbodiimide, N,N'-Di-Cyclohexylcarbodiimide, N,N'-Di-p-Toluylcarbodiimide, N,N'-Ben Dylcarbodiimide, N-octadecyl-N'-phenylcarbodiimide, N-benzyl-N'-phenylcarbodiimide, N-octadecyl-N'-toluylcarbodiimide, N-cyclohexyl-N'-toluylcarbodiimide, N-phenyl-N'-toluylcarbodiimide, N-benzyl-N'-toluylcarbodiimide, N,N'-di-o-ethylphenylcarbodiimide, N,N'-di-p-ethylphenylcarbodiimide, N,N'-di-o-isopropylphenylcarbodiimide, N,N'-di-p-isopropylphenylcarbodiimide Imides, N,N'-di-o-isobutylphenylcarbodiimide, N,N'-di-p-isobutylphenylcarbodiimide, N,N'-di-2,6-diethylphenylcarbodiimide, N,N'-di-2-ethyl-6-isopropylphenylcarbodiimide, N,N'-di-2-isobutyl-6-isopropylphenylcarbodiimide, N,N'-di-2,4,6-trimethylphenylcarbodiimide, N,N'-di-2,4,6-triisopropylphenylcarbodiimide, N,N'-di-2,4,6-triisobutylphenylcarbodiimide, etc.

[0054] Polycarbodiimide compounds include poly(1,6-hexamethylenecarbodiimide), poly(4,4'-methylenebiscyclohexylcarbodiimide), poly(1,3-cyclohexylenecarbodiimide), poly(1,4-cyclohexylenecarbodiimide), poly(4,4'-diphenylmethanecarbodiimide), poly(3,3'-dimethyl-4,4'-diphenylmethanecarbodiimide), poly(naphthylenecarbodiimide), poly(p-phenylenecarbodiimide), poly(m-phenylenecarbodiimide), poly(toluylcarbodiimide), poly(diisopropylcarbodiimide), poly(methyl-diisopropylphenylenecarbodiimide), poly(triethylphenylenecarbodiimide), poly(triisopropylphenylenecarbodiimide), and other polycarbodiimides.

[0055] Among these, preferred are N,N'-di-2,6-diisopropylphenylcarbodiimide, 2,6,2',6'-tetraisopropyldiphenylcarbodiimide, and polycarbodiimide; more preferably poly(1,6-hexamethylenecarbodiimide), poly(4,4'-methylenebiscyclohexylcarbodiimide), poly(1,3-cyclohexylenecarbodiimide), poly(1,4-cyclohexylenecarbodiimide), poly(4,4'-diphenylmethanecarbodiimide), and poly(3,3'-dimethyl-4,4'-diphenylmethane). The polycarbodiimides are poly(carbodiimide), poly(naphthylenecarbodiimide), poly(p-phenylenecarbodiimide), poly(m-phenylenecarbodiimide), poly(toluylcarbodiimide), poly(diisopropylcarbodiimide), poly(methyl-diisopropylphenylenecarbodiimide), poly(triethylphenylenecarbodiimide), and poly(triisopropylphenylenecarbodiimide), with poly(1,4-cyclohexylenecarbodiimide) and poly(triisopropylphenylenecarbodiimide) being particularly preferred.

[0056] Epoxy compounds are preferably epoxy compounds having at least one epoxy group, preferably two or more, in one molecule. Examples include aliphatic epoxy compounds, alicyclic epoxy compounds, aromatic epoxy compounds and their hydrogenated compounds, and aromatic or heterocyclic epoxy compounds.

[0057] Examples of aliphatic epoxy compounds include ethylene glycol diglycidyl ether, polyethylene glycol diglycidyl ether, propylene glycol diglycidyl ether, polypropylene glycol diglycidyl ether, butanediol diglycidyl ether, neopentyl glycol diglycidyl ether, hexanediol diglycidyl ether, glycerin diglycidyl ether, trimethylolpropane triglycidyl ether, and diglycerin tetraglycidyl ether.

[0058] Examples of alicyclic epoxy compounds include dicyclopentadiene dioxide, epoxycyclohexenecarboxylate ethylene glycol diester, 3,4-epoxycyclohexenylmethyl-3'-4'-epoxycyclohexenecarboxylate, and 1,2:8,9-diepoxylimonene.

[0059] Examples of aromatic epoxy compounds and their hydrogenated compounds include aromatic epoxy compounds and their hydrogenated compounds obtained by the reaction of polyphenol compounds such as hydroquinone, resorcinol, bisphenol A, bisphenol F, 4,4'-dihydroxybiphenyl, tetrabromobisphenol A, 2,2-bis(4-hydroxyphenyl)-1,1,1,3,3,3-hexafluoropropane, and glycidyl ether of 1,6-dihydroxynaphthalene with epichlorohydrin. Examples of heterocyclic epoxy compounds include diglycidyl phthalates and triglycidyl isocyanurates. Other preferred compounds include those having an epoxy group at the end of a silicone oil and compounds having an epoxy group with an alkoxysilane.

[0060] The resin compositions of this disclosure exhibit suppressed deterioration in elongation properties (tensile elongation at break) even after prolonged exposure to ultraviolet light. In preferred embodiments of this disclosure, the elongation halving time of the resin compositions based on the examples is preferably 100 hours or more, more preferably 130 hours or more, even more preferably 150 hours or more, and even more preferably 200 hours or more. Since resin compositions (especially molded articles) are used in various environments, it is desirable that they maintain flexibility and toughness (indicated by elongation) over a long period of time. A longer elongation halving time means superior long-term durability (sometimes referred to as weather resistance).

[0061] Method for Manufacturing the Resin Composition The thermoplastic polyester elastomer resin composition of this disclosure can be manufactured by conventionally known methods. In one embodiment, the manufacturing of the resin composition of this disclosure may be carried out in two steps: the manufacture of a thermoplastic polyester elastomer (base polymer) and the manufacture of a resin composition (compound) in which various additives are blended therewith.

[0062] Methods for producing thermoplastic polyester elastomers (base polymers) Examples of methods for producing base polymers include melt polymerization, solution polymerization, and solid-phase polymerization. Suitable methods for producing thermoplastic polyester elastomers include, but are not limited to, (i) a method of obtaining a reaction product by transesterifying a lower alcohol diester of a dicarboxylic acid, an excess amount of low molecular weight glycol, and a soft segment component in the presence of a catalyst, and then polycondensing the reaction product; (ii) a method of obtaining a reaction product by esterifying a dicarboxylic acid, an excess amount of glycol, and a soft segment component in the presence of a catalyst, and then polycondensing the reaction product; (iii) a method of preparing a hard segment polyester in advance, adding a soft segment component to the polyester, and randomizing it by transesterification; (iv) a method of linking hard segments and soft segments with a chain linker; and (v) a method of adding an ε-caprolactone monomer to a hard segment when poly(ε-caprolactone) is used as the soft segment.

[0063] Known catalysts such as phosphorus-based, imidazole-based, antimony-based, germanium-based, and titanium-based catalysts can be used. Various additives may be added during or after production as needed.

[0064] The acid value of the resin composition can be adjusted, for example, by adjusting the polymerization conditions to reduce the acid value of the thermoplastic polyester elastomer, or by adding a thickener to a thermoplastic polyester elastomer with a high acid value to reduce the acid value. The method of adjusting the acid value is not particularly limited.

[0065] As an example of a method for producing a suitable thermoplastic polyester elastomer resin composition, it is preferable to add an ultraviolet absorber and additional additives as needed (e.g., light shielding agents, light stabilizers, etc.) to a thermoplastic polyester elastomer (which may contain additives), melt-knead the mixture, and then cool and solidify the molten resin composition into any desired shape, such as pellets, to produce the resin composition. In one embodiment, it is preferable to uniformly disperse additives such as light shielding agents using, for example, a masterbatch or side feed.

[0066] In one embodiment, conventional thermoplastic resin mixing equipment such as a single-screw or twin-screw screw extruder or a kneader-type heater can be used for melt mixing. In one embodiment, after melt mixing, the molten resin discharged from the die hole can be pelletized by a strand-cutting method or a hot-cutting method.

[0067] The thermoplastic polyester elastomer resin composition of this disclosure, with the above configuration, has excellent weather resistance, and in a preferred embodiment, it can further improve hydrolysis resistance and eliminate problems such as mesh clogging and machine contamination (e.g., mold contamination) during extrusion in the manufacturing process, thereby improving productivity. Molded articles using the resin composition of this disclosure also have excellent weather resistance, and in a preferred embodiment, they also have excellent hydrolysis resistance, making them particularly suitable for fields where weather resistance is required. Furthermore, since the thermoplastic polyester elastomer resin composition of this disclosure can obtain high weather resistance even without containing a light-shielding agent, it has good colorability with pigments, dyes, etc., and can be particularly suitable for use in fields where design is required.

[0068] Molded articles and their applications: Molded articles using the resin composition of this disclosure include a wide range of components and products used in various fields, such as automotive parts, electrical and electronic components, fibers, sheets, films, bottles, and containers. The resin composition of this disclosure may be used as part of the entire molded article or as a component of a part of it. The method for manufacturing a molded article using the resin composition of this disclosure is not particularly limited, and a molded article of a desired shape can be produced by various known methods. Examples include injection molding, blow molding, extrusion molding, foam molding, distorted molding, calendering, die molding, and various other molding methods, with injection molding being preferred.

[0069] This application claims the benefit of priority under Japanese Application No. 2025-048583, filed on 24 March 2025. The entire specification of Japanese Application No. 2025-048583 is incorporated herein by reference.

[0070] The present invention will be described in more detail below with reference to examples, but the present invention is not limited by the following examples, and it is certainly possible to implement it with appropriate modifications within the scope that is consistent with the spirit of the preceding and following descriptions, and such modifications are also included within the technical scope of the present invention.

[0071] Raw Materials Used The main raw materials used in this example are as follows: [Thermoplastic Polyester Elastomer (A)] (A-1) Thermoplastic polyester elastomer (A-1) was synthesized using dimethyl terephthalate, 1,4-butanediol, and poly(tetramethylene oxide) glycol with a number average molecular weight of 1000 as raw materials, with a soft segment component content of 40.9 parts by mass.

[0072] (A-2) Thermoplastic polyester elastomer (A-2) was synthesized using dimethyl terephthalate, 1,4-butanediol, and poly(tetramethylene oxide) glycol with a number average molecular weight of 1500 as raw materials, with a soft segment component content of 47.1 parts by mass.

[0073] (A-3) Thermoplastic polyester elastomer The thermoplastic polyester elastomer synthesized in (A-2) was made highly viscous by solid-phase polymerization to obtain thermoplastic polyester elastomer (A-3).

[0074] (A-4) Thermoplastic polyester elastomer: A thermoplastic polyester elastomer (manufactured by SK Chemical Co., Ltd., G155D, containing 40.8 parts by mass of soft segment component) was used.

[0075] [UV absorbers (B)] (B-1) UV absorber (UVA) Benzotriazole-based UV absorber (manufactured by Chemipro Chemicals Co., Ltd., KEMISORB73, molecular weight 316, melting point 138-141°C) (B-2) UV absorber (UVA) Triazine-based UV absorber (manufactured by ADEKA Corporation, ADEKA Stab LA-F70, molecular weight 700, melting point 144-150°C) (B-3) UV absorber (UVA) Benzotriazole-based UV absorber (manufactured by Chemipro Chemicals Co., Ltd., KEMISORB279, molecular weight 659, melting point 194-200°C) (B-4) UV absorber (UVA) Benzophenone-based UV absorber (manufactured by Chemipro Chemicals Co., Ltd., KEMISORB111, molecular weight 244, melting point 70°C or higher) (B-5) UV absorber (UVA) (B-6) UV absorber (UVA) Benzotriazole-based UV absorber (manufactured by Double Bond Chemical, CHISORB234, molecular weight 448, melting point 137-141°C) Benzotriazole-based UV absorber (manufactured by Johoku Chemical Industry Co., Ltd., JAST-500, molecular weight 500, melting point 148°C) (B-7) UV absorber (UVA) Benzophenone-based UV absorber (manufactured by Chemipro Chemical Co., Ltd., KEMISORB11, molecular weight 228, melting point 62°C or higher) (B-8) UV absorber (UVA) Triazine-based UV absorber (manufactured by Sumika Chemtex Co., Ltd., SUMISORB130, molecular weight 326, melting point 45°C or higher) (B-9) UV absorber (UVA) Triazine-based UV absorber (manufactured by Chemipro Chemicals Co., Ltd., KEMISORB102, molecular weight 510, melting point 90°C or higher) (B-10) UV absorber (UVA) Benzotriazole-based UV absorber (manufactured by Sumika Chemtex Co., Ltd., SUMISORB250, molecular weight 389, melting point 159°C or higher)

[0076] [Absorbance of UV Absorbers] The method for measuring the absorption wavelength of UV absorbers is as follows: 10 mg of UV absorber was weighed out, dissolved in 10 mL of chloroform, and then diluted 100-fold with chloroform. The ultraviolet-visible spectrum of the obtained solution was measured, and the absorbances at each integer wavelength in the range of 370 to 400 nm were summed. Similarly, the absorbances at each integer wavelength in the range of 305 to 315 nm were summed. These sums were calculated as the absorbance for each wavelength range. Specifically, the sum of absorbances at each integer wavelength in the above ranges is the sum of absorbances measured at 1 nm intervals in the ranges of 305 to 315 nm and 370 to 400 nm.

[0077] [Light stabilizer (HALS)] Hindered amine light stabilizer (>NO-Alkyl type) (manufactured by Double Bond Chemical, CHISORB622SF, molecular weight 3100-4000, melting point 50-70°C)

[0078] [Light-blocking agent] Carbon black (manufactured by Nippon Pigment Co., Ltd., EX-3236, polyethylene-based masterbatch with 40% carbon black content) Zinc oxide (manufactured by Sakai Chemical Industry Co., Ltd., zinc oxide type 2) Note that the light-blocking agent in the table refers to the amount of light-blocking agent (parts by mass) in the masterbatch.

[0079] [Thickening agents] Liquid epoxy compounds: Bisphenol F type difunctional epoxy compounds Carbodiimide compounds: Aliphatic polycarbodiimide compounds

[0080] [Catalyst] Phosphorus-based compounds: Triphenylphosphine

[0081] Preparation of Resin Composition [Resin Composition] Each of the above raw materials was supplied to a twin-screw type melt mixer in the ratios shown in the table and mixed. The cylinder temperature during mixing was set to 240°C. The obtained pellet-shaped thermoplastic polyester elastomer resin composition was used as a sample for the following evaluation. The results are shown in the table.

[0082] Evaluation Method [End Acid Value] The sample was dissolved in deuterated chloroform / deuterated hexafluoroisopropanol / triethylamine (88 / 10 / 2 [volume ratio]) and evaluated using a BRUKER AVANCE NEO 600 NMR spectrometer. １ ¹H-NMR analysis was performed, and the resin composition was determined from the integral ratio and expressed in mole percent. Furthermore, based on the resin composition of the sample, the amount of carboxylic acid groups (eq / ton) was calculated using the following formula: Amount of terminal carboxylic acid groups (eq / ton) = (Σ(P / 100) × Q) × 10 ６ / (Σ(R / 100×Z)) P = Content of terminal and carboxylic acid group-containing components (mol%) Q = Number of carboxylic acid groups in one molecule of terminal and carboxylic acid group-containing component R = Content of each component (mol%) Z = Molecular weight of each component

[0083] [Machine Contamination] When molding a sample into a 2mm thick x 100mm x 100mm flat plate using an injection molding machine at a temperature setting of 230°C, the presence or absence of contamination on the mold after 50 consecutive shots was visually checked and evaluated according to the following criteria: ○ (Excellent): No contamination on the mold is visible to the naked eye. △ (Acceptable): Slight contamination on the mold is visible to the naked eye, but does not pose a practical problem. × (Unacceptable): Contamination on the mold is visible to the naked eye and is not practically acceptable.

[0084] [Extrusion Productivity] Using a twin-screw type melting and mixing machine, the cylinder temperature was set to 240°C, and the venting condition and / or mesh clogging before the die during the melting and mixing of raw materials to form pellets was visually checked and evaluated according to the following criteria: ○ (Pass): No venting or mesh clogging was visible to the naked eye. × (Fail): Venting or mesh clogging was visible to the naked eye.

[0085] [Light transmittance] [Light transmittance ratio] The sample was fed into a single-screw extruder and extruded into a 50 μm thick film using a T-die at a set temperature of 230°C. The transmittance (%) of the obtained film at wavelengths of 380 nm and 600 nm was measured using a UV-Vis spectrophotometer (Shimadzu Corporation, SolidSpec-3700). The light transmittance ratio (380 nm / 600 nm) was calculated based on the measured values.

[0086] [Elongation Half-Life Time] Using an injection molding machine, the sample was molded into a flat plate (2 mm thick x 100 mm x 100 mm) at a temperature setting of 230°C. It was then divided into three perpendicular sections to cut out rectangular flat plates (2 mm thick x 100 mm x 33 mm). The cut test pieces were subjected to a weathering test using a Super Xenon Weather Meter SX75 (manufactured by Suga Test Instruments Co., Ltd.) with a maximum duration of 200 hr. Afterward, they were punched out into dumbbell-shaped test pieces (Type 3). A tensile test was performed using the obtained dumbbell-shaped test pieces, and the tensile elongation at break was determined. The weathering test conditions were: irradiation temperature (BPT) 83°C, wavelength 300 nm to 700 nm, and illuminance 500 W / m². ２ There was no rainfall. Tensile tests were performed using Tensilon, and the obtained test specimens were stretched at a speed of 500 mm / min. The elongation at which the test specimen broke was defined as the tensile elongation at break (%). The weathering test time until the tensile elongation of the test specimen before the weathering test became 50% of the tensile elongation at break was evaluated as the elongation halving time.

[0087] [Overall Weather Resistance] (Weather Resistance Evaluation) Weather resistance was evaluated by calculating the time of elongation halving from the tensile elongation at break in each of the above tests. ○ (Pass): Elongation halving time 100 hours or more × (Fail): Elongation halving time less than 100 hours

[0088]

[0089]

[0090] Examples 1 to 13 are thermoplastic polyester elastomer resin compositions in which a single-layer film with a thickness of 50 μm has a light transmittance ratio (380 nm / 600 nm) of less than 0.20 at wavelengths of 380 nm and 600 nm. All of them showed good weather resistance (elongation half-life of 100 hours or more, overall evaluation ○). Examples 1 and 2 used thermoplastic polyester elastomers with different soft segment component contents, but all showed excellent weather resistance, suggesting that the soft segment content does not significantly affect weather resistance. Examples 2 to 5 are examples using preferred ultraviolet absorbers of this disclosure, and all showed good weather resistance. In particular, ultraviolet absorbers (B-1) and (B-2) showed better weather resistance than ultraviolet absorbers (B-3) and (B-4). This is because Examples 2 and 3, which included UV absorbers (B-1) and (B-2), had a more favorable light transmittance ratio than Examples 4 and 5, which included UV absorbers (B-3) and (B-4). This is thought to be because the UV absorbers, which have excellent absorbance at specific wavelengths, effectively absorbed ultraviolet light and prevented resin degradation. Examples 6 and 7 used carbon black and zinc oxide as light shielding agents, respectively, and in a single-layer film with a thickness of 50 μm, the light transmittance ratio (380 nm / 600 nm) at wavelengths of 380 nm and 600 nm was an excellent value of 0.1 or less. This is because the light shielding agent shields not only ultraviolet light but also visible light. Example 9 used a thermoplastic polyester elastomer with a high end acid value, but the weather resistance evaluation was ○ (pass), indicating that a high end acid value does not necessarily reduce weather resistance. In Example 10, a large amount of UV absorber was incorporated, resulting in bleed-out of the UV absorber and a slightly inferior machine contamination rate. Example 13 used a combination of an ultraviolet absorber and a light stabilizer that exhibited excellent absorbance at wavelengths of 370-400 nm, and showed good weather resistance. This is thought to be due to the synergistic effect of the ultraviolet absorber and the light stabilizer. Example 8 used a thermoplastic polyester elastomer that had undergone solid-phase polymerization, Example 11 used a liquid epoxy compound, and Example 12 used a carbodiimide compound, with the terminal acid value adjusted in each case. These examples also showed excellent weather resistance.

[0091]

[0092] Comparative Example 1 was a thermoplastic polyester elastomer alone and did not contain a UV absorber, so its weather resistance was significantly poor. Comparative Examples 2 to 7 were thermoplastic polyester elastomer resin compositions each containing a different UV absorber, but the light transmittance ratio (380 nm / 600 nm) at wavelengths of 380 nm and 600 nm in a single-layer film with a thickness of 50 μm was 0.20 or higher, and the absorbance of the UV absorber used at wavelengths of 370 to 400 nm was insufficient, resulting in insufficient weather resistance (less than 100 hours), and all of them failed the weather resistance evaluation.

[0093] The thermoplastic polyester elastomer resin composition disclosed herein exhibits excellent weather resistance, suppressing the deterioration of mechanical properties, particularly elongation properties, even when exposed to light including ultraviolet rays for extended periods. This property makes it suitable for a wide range of products, including industrial goods such as automotive parts and electrical equipment, as well as consumer goods such as films, sheets, bottles, and containers. In particular, it demonstrates excellent weather resistance in harsh environments, such as outdoor use, where it is directly exposed to sunlight.

Claims

1. A thermoplastic polyester elastomer resin composition comprising (A) a thermoplastic polyester elastomer and (B) an ultraviolet absorber, wherein the light transmittance ratio (380 nm / 600 nm) at wavelengths of 380 nm and 600 nm in a single layer film of the thermoplastic polyester elastomer resin composition with a thickness of 50 μm is less than 0.

20.

2. The thermoplastic polyester elastomer resin composition according to claim 1, wherein the (B) ultraviolet absorber, in a solution dissolved in chloroform at a concentration of 10 mg / L, has a total absorbance of 3.0 or more at each integer wavelength in the range of 370 to 400 nm.

3. The thermoplastic polyester elastomer resin composition according to claim 1, comprising less than 3.0 parts by mass of (B) ultraviolet absorber per 100 parts by mass of (A) thermoplastic polyester elastomer.

4. The thermoplastic polyester elastomer resin composition according to claim 1, wherein the (A) thermoplastic polyester elastomer is a copolymer of a hard segment and a soft segment, and the hard segment comprises an aromatic dicarboxylic acid or an ester-forming derivative thereof and a diol or an ester-forming derivative thereof as constituent components.

5. The thermoplastic polyester elastomer resin composition according to claim 4, wherein the hard segment is a constituent unit derived from butylene terephthalate and / or a constituent unit derived from butylene naphthalate.

6. The thermoplastic polyester elastomer resin composition according to claim 4, wherein the soft segment is at least one selected from the group consisting of aliphatic polyether, aliphatic polyester, and aliphatic polycarbonate.

7. The thermoplastic polyester elastomer resin composition according to claim 6, wherein the soft segment is poly(tetramethylene oxide) glycol.

8. The thermoplastic polyester elastomer resin composition according to claim 1, wherein the (B) ultraviolet absorber is at least one selected from the group consisting of benzophenone-based ultraviolet absorbers, benzotriazole-based ultraviolet absorbers, and triazine-based ultraviolet absorbers.

9. A molded article comprising the thermoplastic polyester elastomer resin composition according to any one of claims 1 to 8.

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