Thermoplastic elastomer composition for tires and tire

Abstract

Provided are a thermoplastic elastomer composition for tires having excellent durability and a tire. The thermoplastic elastomer composition for tires includes a polymer component including a polyester thermoplastic elastomer and at least one resin selected from the group consisting of a polycarbonate resin and a styrene resin, the thermoplastic elastomer composition having a specific heat capacity of 1.7 J / (g·K) or less.

Description

Technical Field

[0001] This invention relates to thermoplastic elastomer compositions for tires and tires. Background Technology

[0002] Tires with thermoplastic elastomer components have been studied to improve tire recyclability. However, thermoplastic elastomers present challenges in durability and other properties due to the lack of chemical bonds between molecular chains found in vulcanized rubber materials. Summary of the Invention

[0003] Technical issues

[0004] The purpose of this invention is to solve the above-mentioned problems and provide a thermoplastic elastomer composition for tires and a tire with excellent durability.

[0005] Solution to the problem

[0006] This invention relates to a thermoplastic elastomer composition for tires, comprising a polymer component including a polyester thermoplastic elastomer and at least one resin selected from polycarbonate resin and styrene resin, wherein the specific heat capacity of the thermoplastic elastomer composition is 1.7 J / (g·K) or less.

[0007] Preferably, the specific heat capacity of the thermoplastic elastomer composition is 1.5 J / (g·K) or less.

[0008] Preferably, based on 100% by mass of each polymer component, the thermoplastic elastomer composition contains 50 to 95% by mass of polyester thermoplastic elastomer and 5 to 50% by mass of polycarbonate resin and styrene resin.

[0009] Preferably, the ratio (ηr / ηe) of the melt shear viscosity (ηr) of at least one resin selected from polycarbonate resin and styrene resin of the thermoplastic elastomer composition to the melt shear viscosity (ηe) of the polyester thermoplastic elastomer is 0.8 to 1.4.

[0010] Preferably, the melting point of the polyester thermoplastic elastomer in the thermoplastic elastomer composition is 180 to 220°C.

[0011] Preferably, in the thermoplastic elastomer composition, the polyester thermoplastic elastomer is a copolymer comprising a polyester forming hard segments and a polymer forming soft segments, wherein the polyester forming hard segments is selected from at least one of polyethylene terephthalate, polybutylene terephthalate, polymethyl terephthalate, polyethylene naphthalate, and polybutylene naphthalate, and the polymer forming soft segments is a polyether.

[0012] Preferably, in the thermoplastic elastomer composition, the polyester thermoplastic elastomer is a copolymer comprising a polyester forming hard segments and a polymer forming soft segments, wherein the polyester forming hard segments is polybutylene terephthalate and the polymer forming soft segments is an aliphatic polyether.

[0013] Preferably, in the thermoplastic elastomer composition, the polycarbonate resin is at least one selected from aromatic polycarbonate, aliphatic polycarbonate and aromatic-aliphatic polycarbonate, and the styrene resin is at least one selected from homopolymers polymerized from a single styrene monomer, copolymers copolymerized from two or more styrene monomers, and copolymers of styrene monomers and other monomers that can be copolymerized therewith.

[0014] Preferably, in the thermoplastic elastomer composition, the polycarbonate resin is an aromatic polycarbonate, and the styrene resin is a homopolymer polymerized from a single styrene monomer.

[0015] Preferably, in the thermoplastic elastomer composition, the polycarbonate resin is a bisphenol A aromatic polycarbonate resin and the styrene resin is polystyrene.

[0016] Preferably, the filler content of the thermoplastic elastomer composition is 5 to 150 parts by weight relative to 100 parts by weight of the polymer component.

[0017] Preferably, the carbon black content of the thermoplastic elastomer composition is 1 to 100 parts by weight relative to 100 parts by weight of the polymer component.

[0018] Preferably, the silica content of the thermoplastic elastomer composition is 25 to 150 parts by weight relative to 100 parts by weight of the polymer component.

[0019] The present invention also relates to a tire comprising the aforementioned thermoplastic elastomer composition.

[0020] Beneficial effects of the invention

[0021] The thermoplastic elastomer composition for tires of the present invention comprises a polymer component comprising a polyester thermoplastic elastomer and at least one resin selected from polycarbonate resins and styrene resins, wherein the specific heat capacity of the thermoplastic elastomer composition is 1.7 J / (g·K) or less. Therefore, the present invention provides a thermoplastic elastomer composition for tires and a tire with excellent durability. Detailed Implementation

[0022] This invention relates to a thermoplastic elastomer composition for tires, comprising a polymer component including a polyester thermoplastic elastomer and at least one resin component selected from polycarbonate resins and styrene resins. The specific heat capacity of the thermoplastic elastomer composition is below 1.7 J / (g·K). Such thermoplastic elastomer compositions exhibit excellent durability.

[0023] The mechanism of this beneficial effect is not yet clear, but it is believed to be as follows:

[0024] Polyester thermoplastic elastomers are highly compatible with rigid resins (carbonate resins and / or styrene resins), resulting in high miscibility. This allows for a reduction in the size of dispersed particles in the rigid resin island phase, thereby improving durability. Furthermore, due to their low specific heat capacity (below 1.7 J / (g·K), lower energy is required to raise the temperature during processes such as injection molding. Therefore, the temperature of the polymer components can be increased (e.g., in an extruder) to improve the dispersibility of the polycarbonate and / or styrene resins, thereby reducing the size of the dispersed resin particles. This increases the surface area of ​​the rigid resin and the number of particles therein, providing stress distribution and thus improving durability. Additionally, the rapid heating rate of the thermoplastic elastomer composition allows for a shorter melting time (e.g., in an injection molding machine) to reduce thermal degradation and prevent a decrease in durability. It is believed that the above-described mechanisms contribute to the excellent durability of thermoplastic elastomer compositions.

[0025] Therefore, the thermoplastic elastomer composition of the present invention solves the problem (objective) of imparting excellent durability by having a specific heat capacity of 1.7 J / (g·K) or less. In other words, having a specific heat capacity of 1.7 J / (g·K) or less does not define the problem (objective); the problem here is to impart excellent durability. To solve this problem, a composition satisfying the above parameters was formulated.

[0026] The specific heat capacity of the thermoplastic elastomer composition is 1.7 J / (g·K) or less. From a durability perspective, the specific heat capacity is preferably 1.5 J / (g·K) or less, more preferably 1.4 J / (g·K) or less, and even more preferably 1.3 J / (g·K) or less. There is no lower limit, but the lower the specific heat capacity, the better.

[0027] In this paper, specific heat capacity can be measured according to JIS K7123:2012 (at a temperature of 25°C), as described in the following examples.

[0028] The specific heat capacity of a thermoplastic elastomer composition can be reduced by one or a combination of the following methods, for example: selecting a material with a low specific heat capacity as a polyester thermoplastic elastomer or a rigid resin (polycarbonate resin and / or styrene resin); adding fillers (e.g., carbon black).

[0029] [Polymer Components]

[0030] (Elastomer components)

[0031] The thermoplastic elastomer composition comprises a polyester thermoplastic elastomer.

[0032] In the thermoplastic elastomer composition, based on 100% by mass of the polymer component, the amount of polyester thermoplastic elastomer is preferably 5% by mass or more, more preferably 30% by mass or more, further preferably 45% by mass or more, particularly preferably 50% by mass or more, and most preferably 60% by mass or more. The upper limit is preferably 98% by mass or less, more preferably 95% by mass or less, and further preferably 93% by mass or less. When the amount of ester thermoplastic elastomer is within the above range, good durability tends to be obtained. In particular, when the amount of polyester thermoplastic elastomer is 50% by mass or more, a sea-island structure can be formed, wherein the polyester thermoplastic elastomer forms the sea phase and the rigid resin (polycarbonate resin and / or styrene resin) forms the island phase.

[0033] In the thermoplastic elastomer composition, based on 100% by mass of the elastomer component, the amount of polyester thermoplastic elastomer is preferably 20% by mass or more, more preferably 40% by mass or more, and even more preferably 50% by mass or more. There is no upper limit, and it can be 100% by mass. From the perspective of the physical properties of the composition, the amount of polyester thermoplastic elastomer can be 95% by mass or less, 90% by mass or less, or 85% by mass or less. When the amount is within the above range, good durability tends to be obtained.

[0034] The term "polyester thermoplastic elastomer" refers to an elastic polymer compound and can be a thermoplastic resin material formed by a copolymer comprising a polymer containing polyester forming crystalline hard segments with high melting points and a polymer forming amorphous soft segments with low glass transition temperatures, the structure of which comprises a portion of polyester.

[0035] Examples of polyester thermoplastic elastomers include ester thermoplastic elastomers (TPCs) as specified in JIS K6418:2007. Specific examples include materials in which at least one polyester forms high-melting-point crystalline hard segments and another polymer (e.g., polyester or polyether) forms low-glass transition-temperature amorphous soft segments.

[0036] The polyester that forms hard segments in a polyester thermoplastic elastomer can be an aromatic polyester. For example, an aromatic polyester can be formed from an aromatic dicarboxylic acid or its ester-forming derivative and an aliphatic diol.

[0037] For example, aromatic polyesters can be polybutylene terephthalate derived from terephthalic acid and / or dimethyl terephthalate and 1,4-butanediol. Other examples of aromatic polyesters include polyesters derived from a dicarboxylic acid component and a diol with a molecular weight of less than 300, wherein the dicarboxylic acid component is, for example, isophthalic acid, phthalic acid, naphthalene-2,6-dicarboxylic acid, naphthalene-2,7-dicarboxylic acid, diphenyl-4,4'-dicarboxylic acid, diphenoxyethane dicarboxylic acid, 5-sulfoisophthalic acid, or ester-forming derivatives thereof, and the diol with a molecular weight of less than 300 is, for example, an aliphatic diol (e.g., ethylene glycol, trimethylene glycol, pentamethylene glycol, hexamethylene glycol, neopentyl glycol, or decamethylene glycol). Alicyclic diols (e.g., 1,4-cyclohexanediethanol or tricyclodecanediethanol) or aromatic diols (e.g., xylene glycol, bis(p-hydroxy)diphenyl, bis(p-hydroxyphenyl)propane, 2,2-bis[4-(2-hydroxyethoxy)phenyl]propane, bis[4-(2-hydroxy)phenyl]sulfone, 1,1-bis[4-(2-hydroxyethoxy)phenyl]cyclohexane, 4,4'-dihydroxy-p-terphenyl or 4,4'-dihydroxy-p-tetraphenyl); and copolymer polyesters obtained by combining two or more of these dicarboxylic acid components or diol components. Furthermore, polyfunctional carboxylic acid components, polyfunctional oxyacid components, polyfunctional hydroxyl components, etc., within the range of less than 5 mol% can be copolymerized.

[0038] Among these polyesters that form hard segments, from the perspective of durability, polyethylene terephthalate, polybutylene terephthalate, polymethyl terephthalate, polyethylene naphthalate, and polybutylene naphthalate are preferred, with polybutylene terephthalate being particularly preferred.

[0039] Examples of polymers forming soft segments in polyester thermoplastic elastomers include aliphatic polyethers and aliphatic polyesters. Examples of aliphatic polyethers include poly(ethylene oxide) glycol, poly(propylene 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. Examples of aliphatic polyesters include poly(ε-caprolactone), polyheptanolide, polyoctanolide, polybutylene adipate, and polyethylene adipate.

[0040] Among these polymers that form soft segments, from the perspective of durability, poly(tetramethylene oxide) glycol, ethylene oxide adducts of poly(propylene oxide) glycol, poly(ε-caprolactone), polybutylene adipate, and polyethylene adipate are preferred.

[0041] From a durability perspective, the number average molecular weight of the polymer (polyester) forming the hard segments is preferably between 300 and 6000. From a durability perspective, the number average molecular weight of the polymer forming the soft segments is preferably between 300 and 6000.

[0042] The mass ratio of hard segments to soft segments in the polyester thermoplastic elastomer (mass of hard segments: mass of soft segments) is preferably 99:1 to 20:80, more preferably 98:2 to 30:70.

[0043] From a durability perspective, the preferred combination of hard and soft segments in polyester thermoplastic elastomers is a combination of polybutylene terephthalate as the hard segment and aliphatic polyether as the soft segment, and more preferably a combination of polybutylene terephthalate as the hard segment and poly(ethylene oxide) glycol as the soft segment. Polyester thermoplastic elastomers can be a single compound or a combination of two or more compounds.

[0044] In this paper, polyester thermoplastic elastomers can be synthesized by copolymerizing polymers forming hard segments with polymers forming soft segments using known methods.

[0045] Examples of available commercial polyester thermoplastic elastomers include: "Keyflex" available from LG Chem Ltd., "PELPRENE" available from Toyobo Co., Ltd., "Hytrel" available from DuPont Toray Industries, Ltd., and "Flexmer" available from Nippon Synthetic Chemical Industries, Ltd.

[0046] The melt shear viscosity (measured at 200°C) of the polyester thermoplastic elastomer is preferably 500 kPa·s or higher, more preferably 600 kPa·s or higher, even more preferably 700 kPa·s or higher, particularly preferably 800 kPa·s or higher, and most preferably 843 kPa·s or higher. The upper limit is preferably 2000 kPa·s or lower, more preferably 1500 kPa·s or lower, even more preferably 1200 kPa·s or lower, particularly preferably 1186 kPa·s or lower, and most preferably 1000 kPa·s or lower. When the melt shear viscosity is within the above range, good durability is tended to be obtained.

[0047] The melting point of the polyester thermoplastic elastomer is preferably above 100°C, more preferably above 150°C, even more preferably above 162°C, and particularly preferably above 180°C. The upper limit is preferably below 300°C, more preferably below 250°C, even more preferably below 220°C, and particularly preferably below 194°C. When the melting point is within the above range, good durability is tended to be obtained.

[0048] Thermoplastic elastomer compositions may contain other thermoplastic elastomers besides polyester thermoplastic elastomers. Examples of other thermoplastic elastomers include olefin thermoplastic elastomers, styrene thermoplastic elastomers (e.g., elastomers of styrene-isobutylene-styrene block copolymers (SIBS), styrene-isoprene-styrene block copolymers (SIS), styrene-isobutylene block copolymers (SIB), styrene-butadiene-styrene block copolymers (SBS), styrene-ethylene / butene-styrene block copolymers (SEBS), styrene-ethylene / propylene-styrene block copolymers (SEPS), styrene-ethylene / ethylene / propylene-styrene block copolymers (SEEPS), and styrene-butadiene / butene-styrene block copolymers (SBBS) elastomers), vinyl chloride thermoplastic elastomers, polyurethane thermoplastic elastomers, polyamide thermoplastic elastomers, and fluorinated thermoplastic elastomers.

[0049] Thermoplastic elastomer compositions may contain elastomer components other than those described above. Examples of such other elastomer components include diene rubbers. Examples of diene rubbers include isoprene rubbers, polybutadiene rubber (BR), styrene-butadiene rubber (SBR), styrene-isoprene-butadiene rubber (SIBR), ethylene-propylene-diene rubber (EPDM), chloroprene rubber (CR), and acrylonitrile-butadiene rubber (NBR). Other examples include butyl rubbers and fluororubbers. These can be used alone or in combination of two or more. Among other elastomers, SBR, BR, and isoprene rubbers are preferred because they are suitable for tire applications.

[0050] Diene rubber can be unmodified or modified. Modified diene rubber can be any diene rubber having functional groups that interact with fillers (e.g., silica). Examples include: end-modified diene rubber obtained by modifying at least one end of the diene rubber with a compound (modifier) ​​having the aforementioned functional groups (i.e., end-modified diene rubber with the functional group at the end); main-chain modified diene rubber having functional groups in the main chain; main-chain and end-modified diene rubber having functional groups in both the main chain and the chain ends (e.g., main-chain and end-modified diene rubber having functional groups in the main chain and at least one chain end modified with a modifier); and end-modified diene rubber having hydroxyl or epoxy groups introduced by modification (coupling) with a polyfunctional compound having two or more epoxy groups within the molecule.

[0051] Examples of the aforementioned functional groups include: amino, amide, silyl, alkoxysilyl, isocyanate, imino, imidazo, urea, ether, carbonyl, oxycarbonyl, mercapto, thioether, dithioether, sulfonyl, sulfinyl, thiocarbonyl, ammonium, imide, hydrazine, azo, diazo, carboxyl, nitrile, pyridinyl, alkoxy, hydroxy, oxygen, and epoxy. These functional groups may be substituted herein. Among these, amino (preferably amino with hydrogen atoms substituted by C1-C6 alkyl groups), alkoxy (preferably C1-C6 alkoxy), and alkoxysilyl (preferably C1-C6 alkoxysilyl) are preferred.

[0052] Any SBR can be used, examples include emulsion-polymerized styrene-butadiene rubber (E-SBR) and solution-polymerized styrene-butadiene rubber (S-SBR). These can be used alone or in combination of two or more.

[0053] The styrene content of the SBR is preferably 5% by mass or more, more preferably 10% by mass or more, and even more preferably 15% by mass or more. The styrene content is also preferably 60% by mass or less, more preferably 40% by mass or less, and even more preferably 30% by mass or less. When the styrene content is within the above range, beneficial effects can be more appropriately achieved.

[0054] In this article, the styrene content of SBR is determined by... 1 H-NMR analysis and measurement.

[0055] For example, SBR products manufactured or sold by companies such as Sumitomo Chemical Co., Ltd., JSR Corporation, Asahi Kasei Corporation, and Zeon Corporation can be used as SBRs.

[0056] SBR can be unmodified or modified. Examples of modified SBR include those SBRs in which functional groups listed for modified diene rubber have been introduced.

[0057] When the thermoplastic elastomer composition contains SBR, the amount of SBR is preferably 5% by mass or more, more preferably 10% by mass or more, and even more preferably 20% by mass or more, based on 100% by mass of the polymer component. The upper limit is preferably 80% by mass or less, more preferably 60% by mass or less, and even more preferably 50% by mass or less. When the amount of SBR is within the above range, good durability tends to be obtained.

[0058] When the thermoplastic elastomer composition contains SBR, the amount of SBR is preferably 5% by mass or more, more preferably 10% by mass or more, and even more preferably 20% by mass or more, based on 100% by mass of the elastomer component. The upper limit is preferably 80% by mass or less, more preferably 60% by mass or less, and even more preferably 50% by mass or less. When the amount of SBR is within the above range, good durability tends to be obtained.

[0059] Any type of BR can be used, including high-cis BR with a high cis content, BR containing syndiotactic polybutadiene crystals, and BR synthesized using rare earth catalysts (rare earth catalyzed BR). These can be used alone or in combination of two or more. To improve wear resistance, high-cis BR with a cis content of 90% by mass or more is preferred.

[0060] Furthermore, BR can be unmodified or modified. Examples of modified BR include those BRs to which functional groups listed for modified diene rubber have been introduced.

[0061] When the thermoplastic elastomer composition contains BR, the amount of BR, based on 100% by mass of the polymer component, is preferably 5% by mass or more, more preferably 10% by mass or more, and even more preferably 20% by mass or more. The upper limit is preferably 80% by mass or less, more preferably 60% by mass or less, and even more preferably 50% by mass or less. When the amount of BR is within the above range, good durability tends to be obtained.

[0062] When the thermoplastic elastomer composition contains BR, the amount of BR, based on 100% by mass of the elastomer component, is preferably 5% by mass or more, more preferably 10% by mass or more, and even more preferably 20% by mass or more. The upper limit is preferably 80% by mass or less, more preferably 60% by mass or less, and even more preferably 50% by mass or less. When the amount of BR is within the above range, good durability tends to be obtained.

[0063] Available BR products can be obtained from Ube Industries, Ltd., JSR Corporation, Asahi Kasei Corporation, Zeon Corporation, and others.

[0064] Examples of isoprene-based rubbers include natural rubber (NR), polyisoprene rubber (IR), refined NR, modified NR, and modified IR. Examples of NR include those commonly used in the rubber industry, such as SIR20, RSS#3, and TSR20. Any IR can be used, including those commonly used in the rubber industry, such as IR2200. Examples of refined NR include deproteinized natural rubber (DPNR) and high-purity natural rubber (UPNR). Examples of modified NR include epoxidized natural rubber (ENR), hydrogenated natural rubber (HNR), and grafted natural rubber. Examples of modified IR include epoxidized polyisoprene rubber, hydrogenated polyisoprene rubber, and grafted polyisoprene rubber. These can be used alone or in combination of two or more.

[0065] When the thermoplastic elastomer composition contains isoprene-based rubber, the amount of isoprene-based rubber is preferably 5% by mass or more, more preferably 10% by mass or more, and even more preferably 20% by mass or more, based on 100% by mass of the polymer component. The upper limit is preferably 80% by mass or less, more preferably 60% by mass or less, and even more preferably 50% by mass or less. When the amount of isoprene-based rubber is within the above range, good durability tends to be obtained.

[0066] When the thermoplastic elastomer composition contains isoprene-based rubber, the amount of isoprene-based rubber is preferably 5% by mass or more, more preferably 10% by mass or more, and even more preferably 20% by mass or more, based on 100% by mass of the elastomer component. The upper limit is preferably 80% by mass or less, more preferably 60% by mass or less, and even more preferably 50% by mass or less. When the amount of isoprene-based rubber is within the above range, good durability is tended to be obtained.

[0067] (Resin Components)

[0068] The thermoplastic elastomer composition contains at least one resin selected from polycarbonate resin and styrene resin as a resin component.

[0069] In the thermoplastic elastomer composition, based on 100% by mass of the polymer component, the combined amount of polycarbonate resin and styrene resin is preferably 2% by mass or more, more preferably 5% by mass or more, and even more preferably 7% by mass or more. The upper limit is preferably 95% by mass or less, more preferably 70% by mass or less, even more preferably 55% by mass or less, particularly preferably 50% by mass or less, and most preferably 40% by mass or less. When the combined amount of polycarbonate resin and styrene resin is within the above range, good durability tends to be obtained. In particular, when the combined amount of polycarbonate resin and styrene resin is 50% by mass or less, a sea-island structure can be formed, wherein the polyester thermoplastic elastomer forms the sea phase and the rigid resin (polycarbonate resin and / or styrene resin) forms the island phase.

[0070] In the thermoplastic elastomer composition, based on 100% by mass of the resin component, the combined amount of polycarbonate resin and styrene resin is preferably 50% by mass or more, more preferably 70% by mass or more, further preferably 90% by mass or more, and particularly preferably 95% by mass or more. There is no upper limit, and it can be 100% by mass.

[0071] The term "polycarbonate resin" refers to a polymer that can be prepared, for example, by the phosgene process (reaction of a polyhydroxy compound with phosgene) or the transesterification process (reaction of a polyhydroxy compound with a carbonate). In this document, polycarbonate resin includes polyester carbonate resin. The term "polyester carbonate resin" refers to a polymer having structural units linked not only by carbonate bonds but also by ester bonds.

[0072] The polycarbonate resin can be aromatic polycarbonate, aliphatic polycarbonate, or aromatic-aliphatic polycarbonate. Among these, aromatic polycarbonate is preferred.

[0073] Examples of aromatic polycarbonate resins include those prepared by, for example, interfacial polymerization (phosgene process) (reaction of an aromatic dihydroxy compound or a mixture thereof with a small amount of a polyhydroxy compound with phosgene) or melt polymerization (transesterification process) (reaction of a compound or mixture with a diester). These methods can typically be used to produce linear or branched thermoplastic (co)polymers. In this document, those resins prepared by melt polymerization can include those whose amount of terminal hydroxyl groups is controlled by reaction with a capping agent.

[0074] Examples of aromatic dihydroxy compounds include various types, such as 2,2-bis(4-hydroxyphenyl)propane (= bisphenol A), tetramethylbisphenol A, bis(4-hydroxyphenyl)-p-diisopropylbenzene, hydroquinone, resorcinol, and 4,4-dihydroxybiphenyl. Bisphenol A is commonly used. Aromatic dihydroxy compounds bonded to tetraalkylsulfonates, as well as polymers or oligomers having a siloxane structure and containing phenolic hydroxyl groups at both ends, can also be used.

[0075] In the thermoplastic elastomer composition, based on 100% by mass of the polymer component, the amount of polycarbonate resin is preferably 2% by mass or more, more preferably 5% by mass or more, and even more preferably 7% by mass or more. The upper limit is preferably 95% by mass or less, more preferably 70% by mass or less, even more preferably 55% by mass or less, particularly preferably 50% by mass or less, and most preferably 40% by mass or less. When the amount of polycarbonate resin is within the above range, good durability tends to be obtained.

[0076] In the thermoplastic elastomer composition, based on 100% by mass of the resin component, the amount of polycarbonate resin is preferably 50% by mass or more, more preferably 70% by mass or more, further preferably 90% by mass or more, and particularly preferably 95% by mass or more. There is no upper limit, and it can be 100% by mass.

[0077] The melt shear viscosity (measured at 200°C) of the polycarbonate resin is preferably 20,000 kPa·s or higher, more preferably 40,000 kPa·s or higher, even more preferably 45,000 kPa·s or higher, particularly preferably 50,000 kPa·s or higher, and most preferably 52,096 kPa·s or higher. The upper limit is preferably 100,000 kPa·s or lower, more preferably 80,000 kPa·s or lower, and even more preferably 60,000 kPa·s or lower. When the melt shear viscosity is within the above range, good durability is tended to be obtained.

[0078] The melting point of the polycarbonate resin is preferably above 100°C, more preferably above 120°C, even more preferably above 130°C, particularly preferably above 150°C, and most preferably above 154°C. The upper limit is preferably below 300°C, more preferably below 270°C, and even more preferably below 250°C. When the melting point is within the above range, good durability is tended to be obtained.

[0079] The term "styrene resin" refers to a polymer made using styrene monomers as structural monomers. Examples include polymers obtained by polymerization of styrene monomers as the major component (at least 50% by mass). Specific examples include homopolymers obtained by polymerization of a single styrene monomer (e.g., styrene, o-methylstyrene, m-methylstyrene, p-methylstyrene, α-methylstyrene, p-methoxystyrene, p-tert-butylstyrene, p-phenylstyrene, o-chlorostyrene, m-chlorostyrene, p-chlorostyrene), copolymers obtained by copolymerization of two or more styrene monomers, and copolymers of styrene monomers and other monomers that can be copolymerized with them.

[0080] Other examples of monomers include: acrylonitriles (e.g., acrylonitrile and methacrylonitrile); unsaturated carboxylic acids (e.g., acrylic acid and methacrylic acid); unsaturated carboxylic acid esters (e.g., methyl acrylate, methyl methacrylate); dienes (e.g., chloroprene, butadiene and isoprene); alkenes (e.g., 1-butene and 1-pentene); α,β-unsaturated carboxylic acids and their anhydrides (e.g., maleic anhydride).

[0081] From a durability perspective, polystyrene is preferred among the aforementioned styrene resins.

[0082] In the thermoplastic elastomer composition, based on 100% by mass of the polymer component, the amount of styrene resin is preferably 2% by mass or more, more preferably 5% by mass or more, and even more preferably 7% by mass or more. The upper limit is preferably 95% by mass or less, more preferably 70% by mass or less, even more preferably 55% by mass or less, particularly preferably 50% by mass or less, and most preferably 40% by mass or less. When the amount of styrene resin is within the above range, good durability is tended to be obtained.

[0083] In the thermoplastic elastomer composition, based on 100% by mass of the resin component, the amount of styrene resin is preferably 50% by mass or more, more preferably 70% by mass or more, further preferably 90% by mass or more, and particularly preferably 95% by mass or more. There is no upper limit, and it can be 100% by mass.

[0084] The melt shear viscosity (measured at 200°C) of the styrene resin is preferably 200 kPa·s or higher, more preferably 500 kPa·s or higher, and even more preferably 600 kPa·s or higher. The upper limit is preferably 5000 kPa·s or lower, more preferably 3000 kPa·s or lower, even more preferably 2000 kPa·s or lower, particularly preferably 1500 kPa·s or lower, and most preferably 1030 kPa·s or lower. When the melt shear viscosity is within the above range, good durability is tended to be obtained.

[0085] In the thermoplastic elastomer composition, the ratio (ηr / ηe) of the melt shear viscosity (ηr, measured at 200°C) of at least one resin selected from polycarbonate resin and styrene resin to the melt shear viscosity (ηe, measured at 200°C) of the polyester thermoplastic elastomer is preferably 0.5 or more, more preferably 0.7 or more, further preferably 0.8 or more, particularly preferably 0.9 or more, and most preferably 1.2 or more. The upper limit is preferably 50.0 or less, more preferably 43.9 or less, further preferably 3.0 or less, particularly preferably 2.0 or less, and most preferably 1.4 or less. When this ratio is within the above range, specifically, when this ratio is close to 1.0, the size of the dispersed particles of the rigid resin island phase can be minimized, thus tending to obtain good durability. In this document, the melt shear viscosity (ηr) of the resin refers to the shear viscosity of all resin components comprising at least one polycarbonate resin and / or styrene resin.

[0086] In this paper, the melt shear viscosity is obtained by measuring the steady-flow shear viscosity using a rheometer, as described in the following examples.

[0087] The melting point of styrene resin is preferably 80°C or higher, more preferably 90°C or higher, and even more preferably 100°C or higher. The upper limit is preferably 250°C or lower, more preferably 220°C or lower, and even more preferably 200°C or lower. When the melting point is within the above range, good durability is tended to be obtained.

[0088] In the thermoplastic elastomer composition, the ratio (Tr / Te) of the melting point (Tr) of at least one resin selected from polycarbonate resin and styrene resin to the melting point (Te) of the polyester thermoplastic elastomer is preferably 0.5 or more, more preferably 0.7 or more, further preferably 0.8 or more, and particularly preferably 0.9 or more. The upper limit is preferably 5.0 or less, more preferably 3.0 or less, further preferably 2.0 or less, and particularly preferably 1.7 or less. When this ratio is within the above range, the polyester thermoplastic elastomer tends to mix well with the polycarbonate resin and / or styrene resin. Furthermore, when this ratio is close to 1.0, the size of the dispersed particles of the rigid resin island phase can be minimized, thus tending to obtain good durability. Hereinafter, the melting point (Tr) of the resin refers to the melting point of all resin components comprising at least one polycarbonate resin and / or styrene resin.

[0089] In this paper, melting point can be defined, for example, as the peak melting temperature measured using a DSC measuring device.

[0090] Thermoplastic elastomer compositions may contain resins other than polycarbonate resins and styrene resins that are solid at room temperature (25°C). Examples of these other resins include coumarone-indene resins, terpene resins, p-tert-butylphenol acetylene resins, and acrylic resins.

[0091] Coumarin-indene resins include resins containing coumarone and indene as monomeric components forming the resin backbone (main chain). Examples of monomeric components that may be included in the backbone besides coumarone and indene include styrene, α-methylstyrene, methylindene, and vinyltoluene.

[0092] Examples of terpene resins include polyterpenes, terpene phenols, and aromatic modified terpene resins.

[0093] The term "polyterpene resin" refers to a resin prepared by polymerizing a terpene compound or a hydrogenated product of such a resin. The term "terpene compound" refers to a compound containing (C5H8). n The hydrocarbons or their oxygen-containing derivatives shown in the diagram each have a terpene backbone and are classified, for example, as monoterpenes (C14-C2 ... 10 H 16 ), sesquiterpenes (C 15 H 24 ) or diterpenes (C 20 H 32 Examples of terpenoid compounds include α-pinene, β-pinene, dipentene, limonene, myrcene, allocirrhene, ocimene, α-phellandrene, α-terpinene, γ-terpinene, terpinene, 1,8-cineole, 1,4-cineole, α-terpineol, β-terpineol, and γ-terpineol.

[0094] Other examples of polyterpene resins include terpene resins made from the aforementioned terpene compounds, such as α-pinene resins, β-pinene resins, limonene resins, dipentene resins, and β-pinene-limonene resins, as well as hydrogenated terpene resins produced by hydrogenation of these terpene resins. Examples of terpene-phenol resins include resins obtained by copolymerization of the aforementioned terpene compounds and phenolic compounds, as well as resins produced by hydrogenation of these resins. Specific examples include resins produced by the condensation of terpene compounds, phenolic compounds, and formaldehyde. In this document, examples of phenolic compounds include phenol, bisphenol A, cresol, and xylenol. Examples of aromatic-modified terpene resins include resins obtained by modifying terpene resins with aromatic compounds, as well as resins produced by hydrogenation of these resins. In this document, aromatic compounds can be any compound having an aromatic ring, and examples of such compounds include: phenolic compounds (e.g., phenol, alkylphenol, alkoxyphenol, phenol containing an unsaturated hydrocarbon group); naphthol compounds (e.g., naphthol, alkylnaphthol, alkoxynaphthol, naphthol containing an unsaturated hydrocarbon group); styrene and styrene derivatives (e.g., alkylstyrene, alkoxystyrene, and styrene containing an unsaturated hydrocarbon group); coumarones and indene.

[0095] Examples of p-tert-butylphenol acetylene resins include resins produced by the condensation of p-tert-butylphenol and acetylene.

[0096] Suitable examples of acrylic resins include, but are not limited to, solvent-free acrylic resins because they contain very few impurities and have a sharp molecular weight distribution.

[0097] Examples of solvent-free acrylic resins include (meth)acrylic resins (polymers) synthesized by high-temperature continuous polymerization (high-temperature continuous bulk polymerization, such as described in U.S. Patent Nos. 4,414,370, JP S59-6207 A, JP H5-58005 B, JP H1-313522A, U.S. Patent No. 5,010,166, and the annual research report TREND 2000, Volume 3, pp. 42-45, published by Toa Synthetic Co., Ltd.) using little or no auxiliary materials (e.g., polymerization initiators, chain transfer agents, and organic solvents). In this document, the term "(meth)acrylic acid" refers to both methacrylic acid and acrylic acid.

[0098] Preferably, the acrylic resin is substantially free of auxiliary materials such as polymerization initiators, chain transfer agents, and organic solvents. Furthermore, the acrylic resin is preferably one prepared by continuous polymerization and has a relatively narrow compositional or molecular weight distribution.

[0099] As described above, acrylic resins are preferably those that are substantially free of auxiliary materials such as polymerization initiators, chain transfer agents, and organic solvents (i.e., high purity). The purity of the acrylic resin (the resin content in the resin) is preferably 95% by mass or more, more preferably 97% by mass or more.

[0100] Examples of monomeric components of acrylic resins include (meth)acrylic acid and (meth)acrylic acid derivatives (e.g., (meth)acrylates (e.g., alkyl esters, aryl esters and aralkyl esters)), (meth)acrylamide and (meth)acrylamide derivatives.

[0101] In addition to (meth)acrylic acid or (meth)acrylic acid derivatives, aromatic vinyl groups such as styrene, α-methylstyrene, vinyltoluene, vinylnaphthalene, divinylbenzene, trivinylbenzene, or divinylnaphthalene can also be used as monomer components of acrylic resins.

[0102] Acrylic resins may consist of only (meth)acrylic acid components, or they may contain components other than (meth)acrylic acid components.

[0103] In addition, acrylic resins may contain hydroxyl, carboxyl, silanol, etc.

[0104] Available resin components (e.g., polycarbonate resin, styrene resin) can be obtained from companies such as Mitsubishi Engineering Plastics Co., Ltd., PS Japan Co., Ltd., Maruzen Petrochemical Co., Ltd., Sumitomo Bakelite Co., Ltd., Yasuhara Chemical Co., Ltd., Tosoh Co., Ltd., Rugers Chemical, BASF, Arizona Chemical, Nitto Chemical Co., Ltd., Nippon Shokubai Co., Ltd., Arakawa Chemical Co., Ltd., Taoka Chemical Co., Ltd., etc.

[0105] [filler]

[0106] Thermoplastic elastomer compositions may contain fillers. Any filler can be used, including materials known in the field of elastomers, such as silica, carbon black, calcium carbonate, talc, alumina, clay, aluminum hydroxide, aluminum oxide, and mica. Among these, carbon black or silica is preferred.

[0107] In the thermoplastic elastomer composition, the amount of filler (total filler content) relative to 100 parts by weight of the polymer component is preferably 5 parts by weight or more, more preferably 8 parts by weight or more, even more preferably 10 parts by weight or more, and particularly preferably 20 parts by weight or more. Furthermore, the upper limit is preferably 150 parts by weight or less, more preferably 120 parts by weight or less, and even more preferably 100 parts by weight or less. When the amount of filler is within the above range, good durability tends to be obtained.

[0108] Any type of carbon black can be used, including examples such as N134, N110, N220, N234, N219, N339, N330, N326, N351, N550, and N762. Available products are available from Asahi Carbon Co., Ltd., Cabot Corporation (Japan), Tokai Carbon Co., Ltd., Mitsubishi Chemical Co., Ltd., Lion Corporation, Shin-Nippon Chemical Carbon Co., Ltd., Columbia Carbon, etc. These can be used alone or in combination of two or more.

[0109] The amount of carbon black relative to 100 parts by mass of the polymer component is preferably 1 part by mass or more, more preferably 3 parts by mass or more, even more preferably 5 parts by mass or more, and particularly preferably 20 parts by mass or more. The amount of carbon black is also preferably 100 parts by mass or less, more preferably 80 parts by mass or less, and even more preferably 50 parts by mass or less. When the amount of carbon black is within the above range, good durability is tended to be obtained.

[0110] The nitrogen adsorption specific surface area (N2SA) of carbon black is preferably 10 m² / s. 2 / g or more, preferably 30m 2 / g or more, further preferably 40m 2 / g or more. N2SA is also preferably 200m 2 / g or less, more preferably 150m 2 / g or less, more preferably 130m2 / g or less. When N2SA does not exceed the upper limit, carbon black tends to provide good dispersion.

[0111] In this paper, the nitrogen adsorption specific surface area of ​​carbon black can be determined according to JIS K6217-2:2001.

[0112] Examples of silica include dry silica (anhydrous silica) and wet silica (hydrated silica). Of these, wet silica is preferred because it contains a large number of silanol groups. Commercially available products are available from companies such as Degussa, Rhodia, Tosoh Silicon Chemicals Co., Ltd., Solvay Japan, and Tokuyama Corporation. These can be used alone or in combination of two or more.

[0113] The amount of silica relative to 100 parts by weight of the polymer component is preferably 25 parts by weight or more, more preferably 30 parts by weight or more, and even more preferably 50 parts by weight or more. There is no upper limit, but it is preferably 150 parts by weight or less, more preferably 130 parts by weight or less, and even more preferably 120 parts by weight or less. When the amount of silica is within the above range, good durability tends to be obtained.

[0114] The nitrogen adsorption specific surface area (N2SA) of silica is preferably 50 m² / s. 2 / g or more, preferably 80m 2 / g or more, further preferably 100m 2 / g or more. Furthermore, there is no upper limit to the N2SA content of silica, but 350 mg / g is preferred. 2 / g or less, more preferably 300m 2 / g or less, more preferably 250m 2 / g or less. When N2SA is within the above range, good durability is tended to be obtained.

[0115] In this paper, the N2SA of silica was measured by the BET method according to ASTM D3037-93.

[0116] The thermoplastic elastomer composition containing silica preferably also contains a silane coupling agent.

[0117] Any silane coupling agent can be used, examples include: sulfide-based silane coupling agents, such as bis(3-triethoxysilylpropyl)tetrasulfide, bis(2-triethoxysilylethyl)tetrasulfide, bis(4-triethoxysilylbutyl)tetrasulfide, bis(3-trimethoxysilylpropyl)tetrasulfide, bis(2-trimethoxysilylethyl)tetrasulfide, bis(2-triethoxysilylethyl)trisulfide, bis(4-triethoxysilylbutyl)tetrasulfide, bis(3-trimethoxysilylpropyl)tetrasulfide, bis(2-trimethoxysilylethyl)tetrasulfide, bis(2-triethoxysilylethyl)trisulfide, bis(4-triethoxysilylbutyl)tetrasulfide, bis(3-triethoxysilylpropyl)tetrasulfide, bis(2-triethoxysilylethyl)tetrasulfide, bis(3-triethoxysilylpropyl)tetrasulfide, bis(3-triethoxysilylethyl)tetrasulfide, bis(3-triethoxysilylbutyl ... Methoxysilylbutyl trisulfide, bis(3-triethoxysilylpropyl) disulfide, bis(2-triethoxysilylethyl) disulfide, bis(4-triethoxysilylbutyl) disulfide, bis(3-trimethoxysilylpropyl) disulfide, bis(2-trimethoxysilylethyl) disulfide, bis(4-trimethoxysilylbutyl) disulfide, 3-trimethoxysilylpropyl-N,N-dimethylsulfide Carbamoyl tetrasulfide, 2-triethoxysilylethyl-N,N-dimethylthiocarbamoyl tetrasulfide, and 3-triethoxysilylpropyl methacrylate monosulfide; mercapto-based silane coupling agents, such as 3-mercaptopropyltrimethoxysilane, 2-mercaptoethyltriethoxysilane, and NXT and NXT-Z (both available from Momentive); vinyl-based silane coupling agents, such as vinyltriethoxysilane and vinyltrimethoxysilane; Amino silane coupling agents, such as 3-aminopropyltriethoxysilane and 3-aminopropyltrimethoxysilane; epoxypropoxysilane coupling agents, such as γ-epoxypropoxypropyltriethoxysilane and γ-epoxypropoxypropyltrimethoxysilane; nitro silane coupling agents, such as 3-nitropropyltrimethoxysilane and 3-nitropropyltriethoxysilane; and chlorinated silane coupling agents, such as 3-chloropropyltrimethoxysilane and 3-chloropropyltriethoxysilane. Available commercial products are available from Degussa, Momentive, Shin-Etsu Silicones, Tokyo Chemical Industry Co., Ltd., AZmax Corporation, Dow Corning Toray Industries, Ltd., etc. These can be used alone or in combination of two or more.

[0118] The amount of silane coupling agent relative to 100 parts by weight of silica is preferably 3 parts by weight or more, more preferably 6 parts by weight or more. The amount of silane coupling agent is also preferably 20 parts by weight or less, more preferably 15 parts by weight or less. When the amount of silane coupling agent is within the above range, good durability tends to be obtained.

[0119] [Liquid plasticizer]

[0120] Thermoplastic elastomer compositions may contain liquid plasticizers, such as oils and liquid resins, which are liquid at 25°C and have plasticizing properties. These may be used alone or in combination of two or more.

[0121] If a liquid plasticizer is present, the amount of the liquid plasticizer relative to 100 parts by weight of the polymer component is preferably 1 part by weight or more, more preferably 3 parts by weight or more, and even more preferably 5 parts by weight or more. The amount of the liquid plasticizer is also preferably 50 parts by weight or less, more preferably 30 parts by weight or less, and even more preferably 20 parts by weight or less. When the amount of the liquid plasticizer is within the above range, good durability tends to be obtained.

[0122] Oils can include, but are not limited to, conventional oils, including, for example, processing oils (e.g., paraffinic processing oils, aromatic processing oils, and naphthenic processing oils), low polycyclic aromatic (PCA) processing oils (e.g., TDAE and MES), vegetable oils, and mixtures thereof. Aromatic processing oils are preferred among these from the perspective of wear resistance and tensile properties. Specific examples of aromatic processing oils include the Diana Process Oil AH series, available from Idemitsu Kosan Co., Ltd.

[0123] Examples of liquid resins include, but are not limited to, liquid aromatic vinyl polymers, liquid coumarone-indene resins, indene resins, liquid terpene resins, liquid rosin resins, and their hydrogenated products.

[0124] The term "liquid aromatic vinyl polymer" refers to a resin produced by polymerizing α-methylstyrene and / or styrene. Examples include liquid resins such as styrene homopolymers, α-methylstyrene homopolymers, and copolymers of α-methylstyrene and styrene.

[0125] The term "liquid coumarone-indene resin" refers to a resin containing coumarone and indene as the main monomer components forming the resin backbone (main chain). Examples of monomer components that may be included in the backbone besides coumarone and indene include styrene, α-methylstyrene, methylindene, and vinyltoluene.

[0126] The term "liquid indene resin" refers to a liquid resin containing indene as the main monomer component that forms the backbone (main chain) of the resin.

[0127] The term "liquid terpene resin" refers to liquid terpene resins, represented by resins produced by polymerizing terpene compounds (such as α-pinene, β-pinene, camphene, or dipentene) and terpene phenolic resins produced from terpene compounds and phenolic compounds.

[0128] The term "liquid rosin resin" refers to liquid rosin resins, including natural rosin, polymeric rosin, modified rosin, and their ester compounds or their hydrogenated products.

[0129] [Other components]

[0130] From the perspective of properties such as crack resistance and ozone resistance, thermoplastic elastomer compositions preferably contain antioxidants.

[0131] Any antioxidant can be used, examples of which include: naphthylamine antioxidants (e.g., phenyl-α-naphthylamine); diphenylamine antioxidants (e.g., octyl diphenylamine and 4,4'-bis(α,α'-dimethylbenzyl)diphenylamine); p-phenylenediamine antioxidants (e.g., N-isopropyl-N'-phenyl-p-phenylenediamine, N-(1,3-dimethylbutyl)-N'-phenyl-p-phenylenediamine and N,N'-di-2-naphthyl-p-phenylenediamine); quinoline antioxidants (e.g., polymerized 2,2,4-trimethyl-1,2-dihydroquinoline); monophenol antioxidants (e.g., 2,6-di-tert-butyl-4-methylphenol and stylated phenol); and bisphenol, triphenol, or polyphenol antioxidants (e.g., tetra[methylene-3-(3',5'-di-tert-butyl-4'-hydroxyphenyl)propionate]methane). Among these, p-phenylenediamine-based antioxidants and quinoline-based antioxidants are preferred, with N-(1,3-dimethylbutyl)-N'-phenyl-p-phenylenediamine or polymerized 2,2,4-trimethyl-1,2-dihydroquinoline being more preferred. Available commercial products can be obtained from, for example, Seiko Chemical Co., Ltd., Sumitomo Chemical Co., Ltd., Ouchi Shinsei Chemical Co., Ltd., Flextronics, etc.

[0132] The amount of antioxidant is preferably 0.2 parts by mass or more, more preferably 0.5 parts by mass or more, relative to 100 parts by mass of polymer component. Sufficient ozone resistance is tended to be obtained when the amount of antioxidant is not less than the lower limit. The amount of antioxidant is preferably 7.0 parts by mass or less, more preferably 4.0 parts by mass or less. Good appearance is tended to be obtained when the amount of antioxidant does not exceed the upper limit.

[0133] The thermoplastic elastomer composition may contain stearic acid. The amount of stearic acid is preferably at least 0.5 to 10 parts by weight, more preferably 0.5 to 5 parts by weight, relative to 100 parts by weight of the polymer component.

[0134] In this article, stearic acid can be conventional stearic acid. Examples include products available from companies such as Nippon Oil Co., Ltd., Kao Corporation, Fujifilm, Koichi Pure Chemicals Co., Ltd., and Chiba Fatty Acids Co., Ltd.

[0135] Preferably, the thermoplastic elastomer composition contains zinc oxide. The amount of zinc oxide is preferably 0.5 to 10 parts by weight, more preferably 1 to 5 parts by weight, relative to 100 parts by weight of the polymer component.

[0136] In this article, zinc oxide can be conventional zinc oxide. Examples include products available from Mitsui Metal Mining Co., Ltd., Toho Co., Ltd., Hakusui Technology Co., Ltd., Seido Chemical Industry Co., Ltd., Sakai Chemical Co., Ltd., etc.

[0137] Thermoplastic elastomer compositions may contain waxes. Any wax can be used, examples including petroleum waxes and natural waxes, as well as synthetic waxes produced by purifying or chemically treating various waxes. These waxes may be used alone or in combination of two or more.

[0138] Examples of petroleum waxes include paraffin wax and microcrystalline wax. Natural waxes can be any wax derived from non-petroleum resources, including: plant waxes such as candelilla wax, carnauba wax, jasmine wax, rice bran wax, and jojoba wax; animal waxes such as beeswax, lanolin, and cetacean; mineral waxes such as ozokerite, ceresin, and petrolatum; and purified products of these waxes. Available commodities can be obtained from companies such as Ouchi Shinsei Chemical Co., Ltd., Nippon Seika Co., Ltd., and Seiko Chemical Co., Ltd. In this document, the amount of wax can be appropriately selected based on ozone resistance and cost.

[0139] Thermoplastic elastomer compositions may contain sulfur to moderately crosslink polymer chains, thereby providing a good balance between the aforementioned properties.

[0140] The amount of sulfur relative to 100 parts by mass of the polymer component is preferably 0.1 parts by mass or more, more preferably 0.5 parts by mass or more, and even more preferably 0.7 parts by mass or more. The amount of sulfur is preferably 6.0 parts by mass or less, more preferably 4.0 parts by mass or less, and even more preferably 3.0 parts by mass or less.

[0141] Examples of sulfur include those commonly used in the rubber industry, such as powdered sulfur, precipitated sulfur, colloidal sulfur, insoluble sulfur, highly dispersed sulfur, and soluble sulfur. Available commodities can be obtained from companies such as Tsurumi Chemical Industry Co., Ltd., Karuizawa Sulfur Co., Ltd., Shikoku Chemical Industry Co., Ltd., Flex, Nippon Inkryu Kogyo Co., Ltd., and Hosoi Chemical Industry Co., Ltd. These sulfur compounds can be used alone or in combination of two or more.

[0142] Thermoplastic elastomer compositions may contain vulcanization accelerators.

[0143] Although there is no limitation on the amount of vulcanization accelerator, which can be arbitrarily selected according to the desired curing rate or crosslinking density, the amount of vulcanization accelerator is generally 0.3 to 10 parts by weight, preferably 0.5 to 7 parts by weight, relative to 100 parts by weight of polymer component.

[0144] Any type of vulcanization accelerator can be used, including those commonly used. Examples of vulcanization accelerators include: thiazole-based vulcanization accelerators, such as 2-mercaptobenzothiazole, di-2-benzothiazole disulfide, and N-cyclohexyl-2-benzothiazole sulfenamide; thiuram-based vulcanization accelerators, such as tetramethylthiuram disulfide (TMTD), tetrabenzylthiuram disulfide (TBzTD), and tetra(2-ethylhexyl)thiuram disulfide (TOT-N); sulfenamide-based vulcanization accelerators, such as N-cyclohexyl-2-benzothiazole sulfenamide, N-tert-butyl-2-benzothiazole sulfenamide, N-ethoxyethylene-2-benzothiazole sulfenamide, N-ethoxyethylene-2-benzothiazole sulfenamide, and N,N'-diisopropyl-2-benzothiazole sulfenamide; and guanidine-based vulcanization accelerators, such as diphenylguanidine, di-o-tolylguanidine, and o-tolyl biguanide. These vulcanization accelerators can be used alone or in combination of two or more. Considering the balance between the above properties, sulfenamide-based or guanidine-based vulcanization accelerators are preferred among them.

[0145] In addition to the components mentioned above, the thermoplastic elastomer composition may also contain any suitable additives commonly used in the application field, such as release agents and pigments.

[0146] Thermoplastic elastomer compositions can be prepared by known methods. For example, they can be prepared from components such as polyester thermoplastic elastomers, polycarbonate resins, and styrene resins using known molding techniques (e.g., injection molding). Alternatively, for example, they can be prepared by kneading the components in a rubber kneading machine (e.g., an open-roll mill or a Banbury mixer), optionally followed by crosslinking. Kneading conditions may include: a kneading temperature typically from 50 to 200°C, preferably from 80 to 190°C, and a kneading time typically from 30 seconds to 30 minutes, preferably from 1 to 30 minutes.

[0147] Thermoplastic elastomer compositions are used in tires, examples of which include pneumatic tires and airless tires. Among these, pneumatic tires are preferred. For example, tires can be suitably used as summer tires or winter tires (e.g., studless winter tires, snow tires, studded tires). Tires can be used as tires for passenger cars, large passenger cars, large SUVs, heavy vehicles such as trucks and buses, light trucks, motorcycles, racing tires (high-performance tires), etc.

[0148] Tires can be produced from thermoplastic elastomer compositions using conventional methods. For example, they can be produced from components such as polyester thermoplastic elastomers, polycarbonate resins, and styrene resins using known molding techniques (e.g., injection molding). Alternatively, tires can be produced by extruding an uncured thermoplastic elastomer composition containing the said components into the shape of tire parts, molding it with other tire parts in a conventional manner on a tire forming machine to produce an uncured tire, and then heating and pressurizing the uncured tire in a vulcanizing machine.

[0149] Example

[0150] The present invention will be described in detail with reference to embodiments, but the present invention is not limited to the embodiments.

[0151] The chemicals used are described below.

[0152] TPEE 1 (Polyester thermoplastic elastomer): Hytrel SB754 (block copolymer of polybutylene terephthalate and polyether, melt shear viscosity: 1186 kPa·s (measured at 200°C), melting point: 162°C), obtained from DuPont Toray Industries, Ltd.

[0153] TPEE 2 (Polyester thermoplastic elastomer): Hytrel 4767N (block copolymer of polybutylene terephthalate and polyether, melt shear viscosity: 843 kPa·s (measured at 200°C), melting point: 194°C), obtained from DuPont Toray Industries, Ltd.

[0154] Resin 1: HF77 (polystyrene resin, melt shear viscosity: 1030 kPa·s (measurement temperature: 200°C), melting point: 100°C), obtained from PS Japan Co., Ltd.

[0155] Resin 2: Iupilon S-2000PS (Bisphenol A aromatic polycarbonate resin, melt shear viscosity: 52096 kPa·s (measurement temperature: 200℃), melting point: 154℃, obtained from Mitsubishi Engineering Plastics Corporation.

[0156] Carbon black: DIABLACK N550 (N2SA: 42m) 2 / g), obtained from Mitsubishi Chemical Corporation.

[0157] (Preparation of samples for evaluation)

[0158] Samples for evaluation were prepared by injection molding the materials of each formulation shown in Table 1 into the shape of a tire sidewall with an outer diameter of 260 mm, an inner diameter of 125 mm, and a thickness of 4 mm using a twin-screw extruder.

[0159] The melt shear viscosity of the resins and thermoplastic elastomers used, as well as the specific heat capacity and durability of the samples used for evaluation, are measured and evaluated as follows.

[0160] <Measuring Melt Shear Viscosity>

[0161] The melt shear viscosity of the sample used for evaluation was measured using a capillary rheometer under the following conditions (according to JIS K7199).

[0162] (Measurement conditions)

[0163] -L / D=10 / 1

[0164] -Temperature: Any temperature that depends on the melting point of the material

[0165] - No Bagley correction

[0166] Measurement of specific heat capacity

[0167] The specific heat capacity of the sample used for evaluation (at a temperature of 25°C) was calculated from differential scanning calorimetry (DSC) data measured according to JIS K7123:2012 "Determination of specific heat capacity of plastics".

[0168] <Durability>

[0169] At room temperature, the samples used for evaluation were repeatedly subjected to 20% compressive deformation in the radial direction at 50 Hz. The time until failure occurred was expressed as an exponent, with a higher exponent indicating better durability.

[0170] Table 1

[0171]

[0172] As shown in Table 1, the compositions of the examples exhibit excellent durability, wherein the compositions of the examples contain a polymer component with a specific heat capacity of less than 1.7 J / (g·K): the polymer component comprises a polyester thermoplastic elastomer and at least one resin selected from polycarbonate resin and styrene resin.

Claims

1. A thermoplastic elastomer composition for tires, comprising a polymer component, said polymer component comprising a polyester thermoplastic elastomer and at least one resin selected from polycarbonate resins and styrene resins, said thermoplastic elastomer composition having a specific heat capacity of 1.5 J / (g•K) or less. in, Based on 100% by mass of the polymer component, the thermoplastic elastomer composition contains 5% to 98% by mass of polyester thermoplastic elastomer and 2% to 95% by mass of polycarbonate resin and styrene resin combined. In the aforementioned polyester thermoplastic elastomer, the polyester forming the hard chain segments is an aromatic polyester. The polycarbonate resin is an aromatic polycarbonate. The polyester thermoplastic elastomer is a copolymer comprising the following polymers: the polymers comprise the polyester forming hard segments and the polymer forming soft segments, wherein the aromatic polyester is selected from at least one of polyethylene terephthalate, polybutylene terephthalate, polymethyl terephthalate, polyethylene naphthalate and polybutylene naphthalate, and the polymer forming soft segments is a polyether.

2. The thermoplastic elastomer composition for tires according to claim 1, wherein, Based on 100% by mass of each polymer component, the thermoplastic elastomer composition contains 50 to 95% by mass of polyester thermoplastic elastomer and 5 to 50% by mass of polycarbonate resin and styrene resin.

3. The thermoplastic elastomer composition for tires according to claim 1 or 2, wherein, The ratio (ηr / ηe) of the melt shear viscosity (ηr) of at least one resin selected from polycarbonate resin and styrene resin of the thermoplastic elastomer composition to the melt shear viscosity (ηe) of the polyester thermoplastic elastomer is from 0.8 to 1.

4.

4. The thermoplastic elastomer composition for tires according to claim 1 or 2, wherein, The melting point of the polyester thermoplastic elastomer is 180 to 220°C.

5. The thermoplastic elastomer composition for tires according to claim 1 or 2, wherein, The polyester thermoplastic elastomer is a copolymer comprising the following polymers: the polymers comprise the polyester forming hard segments and the polymer forming soft segments, wherein the polyester forming hard segments is polybutylene terephthalate and the polymer forming soft segments is an aliphatic polyether.

6. The thermoplastic elastomer composition for tires according to claim 1 or 2, wherein, The styrene resin is selected from at least one of the following: homopolymers polymerized from a single styrene monomer, copolymers copolymerized from two or more styrene monomers, and copolymers of a styrene monomer and other monomers that can be copolymerized therewith.

7. The thermoplastic elastomer composition for tires according to claim 1 or 2, wherein, The styrene resin is a homopolymer polymerized from a single styrene monomer.

8. The thermoplastic elastomer composition for tires according to claim 1 or 2, wherein, The polycarbonate resin is a bisphenol A aromatic polycarbonate resin, and the styrene resin is polystyrene.

9. The thermoplastic elastomer composition for tires according to claim 1 or 2, wherein, The filler content of the thermoplastic elastomer composition is 5 to 150 parts by weight relative to 100 parts by weight of the polymer component.

10. The thermoplastic elastomer composition for tires according to claim 1 or 2, wherein, The carbon black content of the thermoplastic elastomer composition is 1 to 100 parts by weight relative to 100 parts by weight of the polymer component.

11. The thermoplastic elastomer composition for tires according to claim 1 or 2, wherein, The silica content of the thermoplastic elastomer composition is 25 to 150 parts by weight relative to 100 parts by weight of the polymer component.

12. The thermoplastic elastomer composition for tires according to claim 1 or 2, wherein, The mass ratio of hard segments to soft segments in the polyester thermoplastic elastomer, i.e., the mass of hard segments: the mass of soft segments, is 99:1 to 20:

80.

13. The thermoplastic elastomer composition for tires according to claim 1 or 2, wherein, The polycarbonate resin has a melting point of 100°C or higher.

14. A tire comprising the thermoplastic elastomer composition of claim 1 or 2.

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