Thermoplastic elastomer composition

Abstract

To provide a thermoplastic elastomer composition which has transparency, flexibility and compatibility and further has excellent adhesion to a hard polar resin.SOLUTION: There is provided a thermoplastic elastomer composition which comprises (A) a polyester-based thermoplastic elastomer, (B) a hydrogenated product of a block copolymer of an aromatic vinyl compound having a mass average molecular weight of 350000 or less and a conjugated diene compound, (C) a block copolymer of an aromatic vinyl compound and a conjugated diene compound or an amine modified product of the hydrogenated product and (D) a softener for a non-aromatic rubber.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to a thermoplastic elastomer composition, and more specifically to a thermoplastic elastomer composition that has transparency, flexibility, and compatibility, and has excellent adhesion to hard polar resins such as polycarbonate resin (hereinafter sometimes abbreviated as PC) and acrylonitrile-butadiene-styrene copolymer resin (hereinafter sometimes abbreviated as ABS). [Background technology]

[0002] Thermoplastic elastomers, especially those containing polyester-based thermoplastic elastomers (hereinafter sometimes abbreviated as TPEE), have excellent mechanical properties such as strength, impact resistance, elastic recovery, and flexibility, as well as low-temperature and constant-temperature characteristics, and also have excellent oil and abrasion resistance.In addition, they can be heat-sealed to hard polar resins such as PC and ABS, so they are widely used in fields such as automobiles, electrical and electronic parts, and consumer goods.

[0003] In recent years, TPEE has been made flexible with rubber polymers and plasticizers, and its soft feel, oil resistance, and abrasion resistance have been noted. Applications for grips or packings in cameras, power tools, bicycles, etc. have been investigated and put to practical use.

[0004] TPEE is also used in various molded articles and applications as a thermoplastic elastomer composition alloyed with other elastomers and additives in addition to rubber polymers.

[0005] As an example of an elastomer composition containing such TPEE, Patent Document 1 discloses a thermoplastic elastomer composition that is a blend of a styrene-based thermoplastic elastomer (hereinafter sometimes abbreviated as SBC), TPEE, and a softener, and that has excellent flexibility, fusion properties to polar resins, and abrasion resistance.

[0006] Furthermore, Patent Document 2 discloses a thermoplastic elastomer composition containing SBC, TPEE, a softener, and an ionomer, which has satisfactory fusibility and transparency, and is excellent in compression set properties and flexibility. [Prior art documents] [Patent documents]

[0007] [Patent Document 1] Japanese Patent Application Publication No. 2017-088812 [Patent Document 2] Japanese Patent Application Laid-Open No. 2016-079226 Summary of the Invention [Problem to be solved by the invention]

[0008] However, the above-mentioned thermoplastic elastomer compositions containing TPEE have not yet reached a satisfactory level in all of transparency, flexibility, compatibility, and adhesion to hard polar resins. Therefore, an object of the present invention is to provide a thermoplastic elastomer composition that has transparency, flexibility, compatibility, and excellent adhesion to hard polar resins. [Means for solving the problem]

[0009] After extensive research, the present inventors discovered that by alloying TPEE, which has excellent adhesion to rigid polar resins and transparency, with a hydrogenated block copolymer of an aromatic vinyl compound and a conjugated diene compound (hereinafter sometimes abbreviated as hydrogenated SBC) using an amine-modified block copolymer of an aromatic vinyl compound and a conjugated diene compound or its hydrogenated product (hereinafter sometimes abbreviated as amine-modified SBC) as a compatibilizer, and further adding a non-aromatic rubber softener, it is possible to achieve a thermoplastic elastomer composition that satisfies all of the requirements for transparency, flexibility, compatibility, and adhesion to rigid polar resins that were not achieved with conventional thermoplastic elastomer compositions containing TPEE. The present invention is based on this discovery. The gist of the present invention is as follows.

[0010] [1] (A) Polyester-based thermoplastic elastomer; (B) a hydrogenated block copolymer of an aromatic vinyl compound and a conjugated diene compound, having a mass-average molecular weight of 350,000 or less; (C) an amine-modified block copolymer of an aromatic vinyl compound and a conjugated diene compound or a hydrogenated product thereof; and (D) Non-aromatic rubber softeners; A thermoplastic elastomer composition comprising: [2] The total of the components (A), (B), and (C) is 100% by mass, 40 to 90 mass % of the component (A); 10 to 45% by mass of the component (B); and 1 to 35% by mass of the component (C) The thermoplastic elastomer composition according to [1], comprising: [3] The thermoplastic elastomer composition according to [1] or [2], wherein the component (A) is a polyester-based thermoplastic elastomer composed of a crystalline phase mainly composed of an aromatic polyester and an amorphous phase mainly composed of an aliphatic polyether. [4] The thermoplastic elastomer composition according to any one of [1] to [3], wherein the component (A) is a polyester-based thermoplastic elastomer having a crystallization temperature of 130 to 160°C. [5] The component (B) is a hydrogenated product of a block copolymer having two or more polymer blocks (X) containing aromatic vinyl units as structural units and one or more copolymer blocks (Y) mainly composed of conjugated diene monomers and aromatic vinyl monomers as structural units, The thermoplastic elastomer composition according to any one of [1] to [4], wherein the copolymer block (Y) is a copolymer block mainly composed of ethylene, butylene, and styrene. [6] The thermoplastic elastomer composition according to any one of [1] to [5], wherein the component (C) is an amine-modified product of a hydrogenated block copolymer of an aromatic vinyl compound and a conjugated diene compound. [7] The thermoplastic elastomer composition according to any one of [1] to [6], wherein the thermoplastic elastomer composition has a haze of 70 or less when formed into a sheet having a thickness of 1 mm. [8] A gripping material comprising the thermoplastic elastomer composition according to any one of [1] to [7]. [9] A writing instrument comprising the grip material described in [8].

[10] A tool comprising the gripping material described in [8].

[11] A price rail made of the thermoplastic elastomer composition according to any one of [1] to [7]. [Effects of the Invention]

[0011] According to the present invention, it is possible to provide a thermoplastic elastomer composition that has transparency, flexibility, compatibility, and excellent adhesion to hard polar resins. DETAILED DESCRIPTION OF THE INVENTION

[0012] The thermoplastic elastomer composition of the present invention contains, as essential components, (A) a polyester-based thermoplastic elastomer, (B) a hydrogenated block copolymer of an aromatic vinyl compound and a conjugated diene compound having a mass-average molecular weight of 350,000 or less, (C) an amine-modified product of a block copolymer of an aromatic vinyl compound and a conjugated diene compound or a hydrogenated product thereof, and (D) a non-aromatic rubber softener. By incorporating these components (A) to (D), a thermoplastic elastomer composition can be obtained that satisfies all of the requirements for transparency, flexibility, and compatibility, while also exhibiting excellent adhesion to rigid polar resins. While the reason for this is unclear, it is believed to be as follows: Specifically, when blending TPEE, which has excellent adhesion to rigid polar resins and transparency, with a styrene-based thermoplastic elastomer such as SBC or its hydrogenated product or a softener to impart flexibility, improving the compatibility of the two components is thought to further improve transparency. Adding an acid-modified SBC to compatibilize TPEE and SBC reduces the transparency of the composition. In the present invention, it is believed that the addition of amine-modified SBC has enabled the realization of a thermoplastic elastomer composition that has transparency, flexibility, compatibility, and excellent adhesion to hard polar resins. Below, each component constituting the thermoplastic elastomer composition of the present invention will be described.

[0013] <(A) Polyester-based thermoplastic elastomer> The (A) polyester-based thermoplastic elastomer (hereinafter, sometimes simply referred to as "component (A)") constituting the thermoplastic elastomer composition of the present invention is a component that improves adhesion to hard polar resins and also improves transparency.

[0014] Polyester-based thermoplastic elastomers include polyether ester block copolymers, polyester-ester block copolymers, and polyether ester-ester block copolymers, which have an aromatic polyester as the crystalline phase and a poly(alkylene oxide) glycol and / or an aliphatic polyester as the amorphous phase.

[0015] The aromatic polyester constituting the crystalline phase is preferably a polymer obtained by copolymerizing a dicarboxylic acid component, of which 60 mol % or more is terephthalic acid, with a diol component. Specific examples of the aromatic polyester component include polyethylene terephthalate, polybutylene terephthalate, polyethylene (terephthalate / isophthalate), and polybutylene (terephthalate / isophthalate).

[0016] Specific examples of poly(alkylene oxide) glycols and aliphatic polyesters that constitute the amorphous phase include polyethylene glycol, poly(1,2- and 1,3-propylene oxide) glycol, poly(tetramethylene oxide) glycol, copolymers of ethylene oxide and propylene oxide, copolymers of ethylene oxide and hydrofuran, polyethylene adipate, polybutylene adipate, poly-ε-caprolactone, polyethylene sebacate, and polybutylene sebacate.

[0017] Specific examples of polyester-based thermoplastic elastomers include polyethylene terephthalate-poly(tetramethylene oxide) glycol block copolymers, polyethylene terephthalate / isophthalate-poly(tetramethylene oxide) glycol block copolymers, polybutylene terephthalate-poly(tetramethylene oxide) glycol block copolymers, polybutylene terephthalate / isophthalate-poly(tetramethylene oxide) glycol block copolymers, polybutylene terephthalate / decanedicarboxylate-poly(tetramethylene oxide) glycol block copolymers, polybutylene terephthalate-poly(propylene oxide / ethylene oxide) glycol block copolymers, polybutylene terephthalate / isophthalate-poly(propylene oxide / ethylene oxide) glycol block copolymers, polybutylene terephthalate / decanedicarboxylate-poly(propylene oxide / ethylene oxide) glycol block copolymers, and polybutylene terephthalate-poly(ethylene oxide) glycol block copolymers.

[0018] Among the above-mentioned polyester-based thermoplastic elastomers, copolymers composed of a crystalline phase mainly composed of an aromatic polyester and an amorphous phase mainly composed of an aliphatic polyether are particularly preferred. In this specification, "main component" refers to a content of more than 50% by mass. The aromatic polyester content in the crystalline phase is preferably 60% by mass or more, more preferably 70% by mass or more, and even more preferably 80% by mass or more.

[0019] Specific examples of the copolymers that can be preferably used include polybutylene terephthalate-poly(tetramethylene oxide) glycol block copolymers, polybutylene terephthalate / isophthalate-poly(tetramethylene oxide) glycol block copolymers, and the like.

[0020] The (A) polyester-based thermoplastic elastomer contained in the thermoplastic elastomer composition of the present invention preferably has a crystallization temperature of 120 to 180° C., more preferably 130 to 160° C., and even more preferably 135 to 150° C. The (A) polyester-based thermoplastic elastomer preferably has a melting temperature of 130 to 200° C., more preferably 145 to 180° C., and even more preferably 150 to 170° C. Furthermore, the (A) polyester-based thermoplastic elastomer preferably has a melting enthalpy of greater than 0 (having a melting peak in the DSC melting curve) and 30 J / g, more preferably 3 to 20 J / g, and even more preferably 5 to 12 J / g.

[0021] The crystallization temperature, melting temperature, and melting enthalpy can be measured by a differential scanning calorimeter (DSC) according to the standard method in accordance with JIS K7151:2012. DSC measurements can be performed, for example, using a Diamond DSC differential scanning calorimeter manufactured by PerkinElmer Japan Co., Ltd., under a program that involves holding at 320°C for 10 minutes, cooling to -50°C at 20°C / min, holding at -50°C for 5 minutes, and then heating to 320°C at 20°C / min. The melting temperature refers to the temperature measured from the second melting curve (the melting curve measured during the final heating process). The crystallization temperature and melting temperature are the peak tops that appear on the highest temperature side, and the melting enthalpy is calculated from the melting temperature that appears on the highest temperature side.

[0022] Furthermore, the crystallite size of the (A) polyester-based thermoplastic elastomer, as measured by wide-angle X-ray diffraction (XRD), is preferably 15 nm or less, more preferably 10 nm or less. By using a polyester-based thermoplastic elastomer with a small crystallite size, the transparency of the molded article made using the composition of the present invention is further improved. Note that the crystallite size can be measured by XRD under the following measurement conditions. First, a central portion of the sample is cut out, fixed to a sample holder, and a diffraction profile is measured using wide-angle X-ray transmission while rotating the holder (Through View, total transmission measurement). The measurement conditions for the XRD measurement are as follows: Equipment: EMPYREAN manufactured by Spectris Accessory: Rotating sample stage X-ray source: Cukα Output: 45kV 40mA Detector: PlXcel3D Scanning speed: 2° / min Step width: 0.0131° (2285 steps)

[0023] The content of component (A) in the thermoplastic elastomer composition of the present invention is preferably 40 to 90% by mass, and more preferably 65 to 85% by mass, based on 100% by mass of the total of components (A), (B), and (C). When the content of component (A) is within the above range, transparency and adhesion to hard polar resins are further improved.

[0024] <(B) Hydrogenated block copolymer of aromatic vinyl compound and conjugated diene compound having a mass average molecular weight of 350,000 or less> The (B) hydrogenated block copolymer of an aromatic vinyl compound and a conjugated diene compound (hereinafter, sometimes simply referred to as "component (B)") constituting the thermoplastic elastomer composition of the present invention is an important component for imparting flexibility to a molded article obtained from the thermoplastic elastomer composition of the present invention and for maintaining transparency.

[0025] The hydrogenated SBC is a block copolymer having a structure such as XY, XYX, YXYX, or XYXYX, which is obtained by hydrogenating a block copolymer consisting of at least one, and preferably two or more, polymer blocks X mainly composed of an aromatic vinyl compound and at least one polymer block Y mainly composed of a conjugated diene compound.

[0026] The polymer block X mainly composed of an aromatic vinyl compound may be a polymer composed of only an aromatic vinyl compound, or may be a copolymer of an aromatic vinyl compound and less than 50% by mass of a conjugated diene compound. The polymer block Y mainly composed of a conjugated diene compound may be a polymer composed of only a conjugated diene compound, or may be a copolymer of a conjugated diene compound and less than 50% by mass of an aromatic vinyl compound.

[0027] Examples of aromatic vinyl compounds include styrene, α-methylstyrene, vinyltoluene, p-tert-butylstyrene, etc., and these may be used alone or in combination of two or more. Among these, styrene is preferred.

[0028] Examples of conjugated diene compounds include butadiene, isoprene, 1,3-pentadiene, 2,3-dimethyl-1,3-butadiene, etc., and these may be used alone or in combination. Among these, butadiene, isoprene, and combinations thereof are preferred, and butadiene is more preferred.

[0029] The polymer block Y is preferably a butadiene-styrene controlled distribution copolymer block Y1. The copolymer block Y1 is a copolymer block having two or more regions containing butadiene units as main structural units and one or more regions containing styrene units as main structural units.

[0030] The region containing butadiene units as the main structural unit in the copolymer block Y1 may be a block of butadiene alone, and the region containing styrene units as the main structural unit may be a block of styrene alone. In this case, it corresponds to an S-EB-S-EB-S type multiblock copolymer. However, since the effects of the present invention can be maintained even if the butadiene block or styrene block constituting the butadiene-styrene controlled distribution copolymer block Y1 contains other vinyl monomers, in this specification, the case where the copolymer block Y1 contains other vinyl monomers will be collectively referred to as a "butadiene-styrene controlled distribution block copolymer" and abbreviated as "S-EB / SS."

[0031] In this specification, a region containing butadiene units as the main structural unit means that the proportion of butadiene units is more than 50% by mass. The proportion of butadiene units is preferably 60% by mass or more, more preferably 70% by mass or more, and even more preferably 80% by mass or more. If the proportion of butadiene units is insufficient, the rubber elasticity of the composition tends to be insufficient, and the flexibility of the obtained molded article tends to be reduced. It is preferable that the vinyl monomer units other than butadiene units are substantially styrene units.

[0032] Furthermore, the region in the copolymer block Y1 containing styrene units as the main structural unit means that the proportion of styrene units is greater than 50% by mass. The proportion of styrene units is preferably 60% by mass or more, more preferably 70% by mass or more, and even more preferably 80% by mass or more. If the proportion of styrene units is insufficient, the transparency of the resulting molded article tends to decrease. It is preferable that the vinyl monomer units other than styrene units are substantially butadiene units.

[0033] Component (B) is obtained by hydrogenating the block copolymer of the aromatic vinyl compound and the conjugated diene compound by a known method, thereby converting the unsaturated bonds derived from the conjugated diene in the polymer block Y into saturated bonds. The hydrogenation ratio is preferably 80% or more, and more preferably 90% or more. If hydrogenation is not performed or is insufficient, the resulting composition may have insufficient heat resistance.

[0034] The proportion of styrene units in component (B) is preferably 40% by mass or more, based on all constituent monomer units, from the viewpoint of maintaining the transparency of the resulting molded article. Furthermore, from the viewpoint of enhancing the rubber elasticity of the composition and imparting flexibility to the resulting molded article, it is preferably 70% by mass or less. From these viewpoints, the proportion of styrene units in component (B) is preferably 40 to 70% by mass, more preferably 55 to 65% by mass, based on all constituent monomer units.

[0035] From the viewpoint of improving the adhesion between the thermoplastic elastomer composition of the present invention and the hard polar resin and imparting flexibility to the resulting molded article, the mass average molecular weight of component (B) must be 350,000 or less. The mass average molecular weight of component (B) is preferably 300,000 or less, more preferably 250,000 or less. From the viewpoint of the heat resistance of the resulting molded article, the mass average molecular weight of component (B) is preferably 100,000 or more, more preferably 120,000 or more. In this specification, the mass average molecular weight refers to the molecular weight converted into polystyrene standards measured by gel permeation chromatography (GPC) using a standard method.

[0036] The content of component (B) in the thermoplastic elastomer composition of the present invention is preferably 10 to 45 mass%, more preferably 15 to 30 mass%, based on 100 mass% of the total of components (A), (B), and (C). When the content of component (B) is within the above range, transparency and adhesion to hard polar resins are further improved.

[0037] <(C) Amine-modified block copolymer of an aromatic vinyl compound and a conjugated diene compound or a hydrogenated product thereof> The thermoplastic elastomer composition of the present invention comprises (C) a block copolymer of an aromatic vinyl compound and a conjugated diene compound, or an amine-modified product thereof (hereinafter sometimes referred to simply as "component (C)"), which plays an important role in compatibilizing components (A) and (B). As a result, molded articles made using the composition can achieve both transparency and adhesion to hard polar resins. The amine-modified SBC is a polymer in which an amine compound is copolymerized (usually graft copolymerized) onto a block copolymer (SBC) of an aromatic vinyl compound and a conjugated diene compound. The amine-modified SBC can be obtained by reacting any SBC with any amine compound using a known method. For example, melt-kneading in the presence of an organic peroxide can be used.

[0038] The SBC used in the amine-modified SBC is a block copolymer consisting of at least one, preferably two or more, polymer blocks X mainly composed of an aromatic vinyl compound and at least one polymer block Y mainly composed of a conjugated diene compound, and has a structure such as XY, XYX, YXYX, XYXYX, etc. In this specification, the term "SBC" does not refer only to the above-mentioned block copolymers, but also includes hydrogenated products of block copolymers of aromatic vinyl compounds and conjugated diene compounds obtained by hydrogenating the block copolymers.

[0039] In the SBC, polymer block X mainly composed of an aromatic vinyl compound may be a polymer composed of only an aromatic vinyl compound or a copolymer of an aromatic vinyl compound and less than 50% by weight of a conjugated diene compound, and polymer block Y mainly composed of a conjugated diene compound may be a polymer composed of only a conjugated diene compound or a copolymer of a conjugated diene compound and less than 50% by weight of an aromatic vinyl compound.

[0040] Examples of aromatic vinyl compounds include styrene, α-methylstyrene, vinyltoluene, p-tert-butylstyrene, etc., and these may be used alone or in combination of two or more. Among these, styrene is preferred.

[0041] Examples of conjugated diene compounds include butadiene, isoprene, 1,3-pentadiene, 2,3-dimethyl-1,3-butadiene, etc., and these may be used alone or in combination. Among these, butadiene, isoprene, and combinations thereof are preferred, and butadiene is more preferred.

[0042] Component (C) may be obtained by hydrogenating the block copolymer of the aromatic vinyl compound and the conjugated diene compound by a known method, thereby converting the unsaturated bonds derived from the conjugated diene in the polymer block Y into saturated bonds. The hydrogenation ratio is preferably 50% or more, more preferably 70% or more. From the viewpoint of improving compatibility with components (A) and (B), it is preferable that component (C) is hydrogenated.

[0043] The proportion of styrene units in component (C), based on all constituent monomer units, is preferably 10% by mass or more from the viewpoint of maintaining the transparency of the resulting molded article. Furthermore, from the viewpoint of enhancing the rubber elasticity of the composition and imparting flexibility to the resulting molded article, it is preferably 80% by mass or less. From these viewpoints, the proportion of styrene units in component (C), based on all constituent monomer units, is preferably 15 to 70% by mass, more preferably 20 to 65% by mass.

[0044] From the viewpoint of imparting heat resistance to a molded article obtained from the thermoplastic elastomer composition of the present invention, component (C) preferably has a mass average molecular weight of 30,000 or more, more preferably 40,000 or more, and from the viewpoint of imparting flexibility to the molded article obtained, preferably has a mass average molecular weight of 800,000 or less, more preferably 500,000 or less.

[0045] Examples of the amine compound used in the amine-modified SBC include aliphatic amine compounds, aromatic amine compounds, and heterocyclic amine compounds, and these may be used alone or in combination of two or more.

[0046] Examples of the aliphatic amine compound include aliphatic primary amine compounds, aliphatic secondary amine compounds, aliphatic tertiary amine compounds, and aliphatic polyamine compounds (aliphatic amine compounds having two or more amine groups in one molecule), and these may be used alone or in combination of two or more.

[0047] Examples of the aliphatic primary amine compound include saturated aliphatic primary amine compounds such as methylamine, ethylamine, propylamine, isopropylamine, butylamine, isobutylamine, tert-butylamine, pentylamine, isopentylamine, hexylamine, heptylamine, octylamine, 2-ethylhexylamine, and cyclohexylamine; and unsaturated aliphatic primary amine compounds such as dodecenylamine, octadecenylamine, and docosenylamine; and the like, and these may be used alone or in combination of two or more.

[0048] Examples of the aliphatic secondary amine compound include saturated aliphatic secondary amine compounds such as dimethylamine, diethylamine, diisobutylamine, and dicyclohexylamine; and unsaturated aliphatic secondary amine compounds, and these may be used alone or in combination of two or more.

[0049] Examples of the aliphatic tertiary amine compound include saturated aliphatic tertiary amine compounds such as trimethylamine, triethylamine, triethanolamine, tributylamine, N,N-diisopropylethylamine, and N,N-dimethylcyclohexylamine; and unsaturated aliphatic tertiary amine compounds such as N,N-dimethyloctadecenylamine, and the like, and these may be used alone or in combination of two or more.

[0050] Examples of the aliphatic polyamine compound include ethylenediamine, hexamethylenediamine, and N,N,N',N'-tetramethylethylenediamine, and these may be used alone or in combination of two or more.

[0051] Examples of aromatic amine compounds include anilines (aniline and its derivatives) and arylalkylamine compounds, and these may be used alone or in combination of two or more.

[0052] Examples of the anilines include primary amine aniline compounds such as aniline, toluidine, xylidine, anisidine, phenetidine, 4-ethylaniline, 2-ethylaniline, and 4-isopropylaniline; secondary amine aniline compounds such as N-methylaniline, N-ethylaniline, and N-isopropylaniline; and tertiary amine aniline compounds such as N,N-dimethylaniline, N,N-diethylaniline, and N,N-diisopropylaniline, and these may be used alone or in combination of two or more.

[0053] Examples of arylalkylamine compounds include arylalkyl primary amine compounds such as benzylamine, 1-phenylethylamine, and 2-phenylethylamine; arylalkyl secondary amine compounds such as N-methylbenzylamine; and arylalkyl tertiary amine compounds such as N,N-diethylbenzylamine, and the like, and these may be used alone or in combination of two or more.

[0054] Examples of heterocyclic amines include pyrrolidine, piperidine, piperazine, imidazole, 2-thienylamine, and 2-thienylmethylamine, and these may be used alone or in combination of two or more.

[0055] The amount of the amine compound may be typically 0.01 parts by mass or more, preferably 0.05 parts by mass or more, per 100 parts by mass of SBC, from the viewpoint of reliably improving adhesion to hard polar resins, while typically 20 parts by mass or less, preferably 10 parts by mass or less, more preferably 5 parts by mass or less, and even more preferably 3 parts by mass or less, from the viewpoint of suppressing gel formation and maintaining good coatability.

[0056] The content of component (C) in the thermoplastic elastomer composition of the present invention is preferably 1 to 35 mass%, more preferably 5 to 20 mass%, based on 100 mass% of the total of components (A), (B), and (C). When the content of component (C) is within the above range, the compatibility and transparency of components (A) and (B) are further improved.

[0057] <(D) Non-aromatic rubber softeners> The non-aromatic rubber softener (D) (hereinafter sometimes referred to simply as "component (D)") constituting the thermoplastic elastomer composition of the present invention plays a role in imparting moldability and flexibility to the thermoplastic elastomer composition. Examples of non-aromatic rubber softeners that can be used as component (D) in the present invention include non-aromatic mineral oils and liquid or low-molecular-weight synthetic softeners. Here, "non-aromatic" means that, for mineral oils, they are not classified as aromatic in the classification below (the number of aromatic carbon atoms is less than 30%). For synthetic oils, this means that aromatic monomers are not used.

[0058] Mineral oils used as rubber softeners are mixtures of one or more of paraffin chains, naphthenic rings, and aromatic rings. They are classified as follows: those with 30 to 45% naphthenic ring carbon atoms are called naphthenic, those with 30% or more aromatic carbon atoms are called aromatic, and those that are neither naphthenic nor aromatic and have paraffin chain carbon atoms that account for 50% or more of the total carbon atoms are called paraffinic.

[0059] The mineral oil-based rubber softeners used as component (D) are classified as paraffinic and naphthenic. Aromatic softeners are undesirable because they dissolve component (B) and prevent the physical properties of the resulting composition from being improved. Paraffinic softeners are preferred as component (D), and paraffinic softeners with fewer aromatic ring components are particularly suitable. Liquid or low-molecular-weight synthetic softeners include polybutene, hydrogenated polybutene, and low-molecular-weight polyisobutylene.

[0060] These non-aromatic rubber softeners preferably have a dynamic viscosity at 37.8°C of 20 to 50,000 cSt, a dynamic viscosity at 100°C of 5 to 1,500 cSt, a pour point of -10 to -15°C, and a flash point (COC) of 170 to 300°C. Furthermore, the mass average molecular weight is preferably 100 to 2,000. In this specification, the dynamic viscosity can be measured by a standard method in accordance with JIS K 2283:2000. The pour point can be measured by a standard method in accordance with JIS K 2269:1987. The flash point (COC) can be measured by a standard method in accordance with JIS K 2265:2007.

[0061] The content of component (D) in the thermoplastic elastomer composition of the present invention is preferably 5 to 100 parts by mass, more preferably 10 to 50 parts by mass, and even more preferably 20 to 40 parts by mass, per 100 parts by mass of the total of components (A), (B), and (C). When the content of component (D) is within the above range, flexibility is easily controlled, moldability is further improved, and bleeding out of the softener is suppressed, thereby preventing a decrease in strength and stickiness.

[0062] <Other ingredients> In addition to the above components (A) to (D), the transparent thermoplastic elastomer composition of the present invention may contain, within the scope of the object of the present invention, heat stabilizers, antioxidants, light stabilizers, ultraviolet absorbers, nucleating agents, antiblocking agents, sealability improvers, release agents such as stearic acid and silicone oil, lubricants such as polyethylene wax, colorants, and foaming agents (organic and inorganic). There are no particular restrictions on the additives mentioned above, and known additives can be used. For example, phenol-based antioxidants, phosphite-based antioxidants, thioether-based antioxidants, and the like can be used as antioxidants.

[0063] <Method of producing thermoplastic elastomer composition> The transparent thermoplastic elastomer composition of the present invention can be produced by adding the above components (A) to (D), or other components as needed, simultaneously or in any order, and melt-kneading the components.

[0064] The melt-kneading method is not particularly limited, and commonly known methods can be used. For example, a single-screw extruder, a twin-screw extruder, a roll, a Banbury mixer, or various kneaders can be used. For example, by using a twin-screw extruder, a Banbury mixer, a pressure kneader, or the like with an appropriate L / D, the above operation can be carried out continuously. The melt-kneading temperature can be appropriately set depending on the blending ratio of each component, but is preferably 160 to 220°C.

[0065] The transparent thermoplastic elastomer composition of the present invention obtained in this manner is a composition that has transparency and flexibility and excellent adhesion to rigid polar resins, obtained by alloying TPEE, which has excellent adhesion to rigid polar resins and transparency, with hydrogenated SBC, which is important for imparting flexibility and maintaining transparency, via amine-modified SBC, which contributes to the compatibility of the two components.

[0066] From the viewpoint of flexibility, the transparent thermoplastic elastomer composition of the present invention preferably has a hardness of 80 or less, more preferably 70 or less, measured in accordance with JIS K6253 (HDA after 15 seconds).

[0067] Furthermore, the transparent thermoplastic elastomer composition of the present invention, when formed into a sheet having a thickness of 1 mm, preferably has a haze of at least 70 as measured in accordance with JIS K7105. The haze can be measured by producing a pressed sheet having a thickness of 1 mm from the transparent thermoplastic elastomer composition using an extrusion molding machine and measuring the haze with a haze meter.

[0068] <Application> Due to the properties described above, the transparent thermoplastic elastomer composition of the present invention is suitable for grips of writing implements, tools, cameras, bicycles, etc. It is also useful as a joining member for joining transparent polar resin members such as ply rails. [Example]

[0069] Next, the embodiments of the present invention will be specifically described with reference to the following examples, but the present invention is not limited to these examples.

[0070] In this specification, the manufacturing methods, evaluation methods and raw materials of the test specimens used in the examples and comparative examples are as follows.

[0071] <Evaluation method> (1)Hardness Hardness was measured in accordance with JIS K6253 (HDA after 15 seconds) using a Type A Durometer (manufactured by Kobunshi Keiki Co., Ltd.) Test specimens were prepared by extrusion molding using 6 mm thick press sheets prepared from each composition shown in Table 1.

[0072] (2) Transparency (haze) Haze measurements were carried out in accordance with JIS K7105 using a direct-reading haze meter (manufactured by Toyo Seiki Seisakusho, Ltd.) Each composition shown in Table 1 was pressed into a 1 mm thick sheet using an extrusion molding machine to prepare a test specimen.

[0073] (3) Hard polar resin adhesiveness The adhesion to the adherends (PC board and ABS board) was evaluated as follows. Each composition shown in Table 1 was adhered to the adherends 1 and 2 shown below by injection molding, and the resulting specimens were used for evaluation. Substrate 1: PC (Mitsubishi Engineering Plastics Corporation, Iupilon S-2000), Substrate 2: ABS (Techno UMG Co., Ltd., UMG ABS EX10U)

[0074] An adherend with a thickness of 4 mm, width of 25 mm, and length of 150 mm was prepared by injection molding, and a molded product with a thickness of 3 mm, width of 25 mm, and length of 200 mm, which was molded from each composition using an extrusion molding machine, was bonded to the adherend by insert molding. At this time, a paper was sandwiched between the adherends, and the adhesive surface was 2000 mm. 2 The molding was carried out so that Next, the adherend was fixed and a 180-degree peel test was carried out at a pulling rate of 100 mm / min. The evaluation criteria were as follows: ◎: Material breaks before peeling ○: Peel strength is 1N / mm or more ×: Peel strength is less than 1N / mm

[0075] (4) Compatibility (surface layer releasability) A 2 mm thick injection sheet was produced from each composition shown in Table 1 using an injection molding machine, and the film gate was visually inspected for peeling of the surface layer. The evaluation criteria for compatibility (surface peelability) were as follows: ○: No peeling ×: Peeling occurred

[0076] <Materials used> (A) Polyester-based thermoplastic elastomer (A-1) Polybutylene terephthalate-poly(tetramethylene oxide) glycol block copolymer (Hytrel 3001-X01 (trade name), manufactured by DuPont-Toray Co., Ltd., crystallization temperature measured by differential scanning calorimetry (DSC) was 142°C, melting temperature was 160°C, fusion enthalpy was 6 J / g, and crystallite size measured by wide-angle X-ray diffraction (XRD) was 7 nm) (A-2) A polyester-based thermoplastic elastomer consisting of a crystalline phase mainly composed of polybutylene terephthalate and an amorphous phase mainly composed of polytetramethylene ether glycol. (Hytrel 4001-X04 (trade name), manufactured by DuPont-Toray Co., Ltd., crystallization temperature measured by differential scanning calorimetry (DSC) was 161°C, melting temperature was 183°C, fusion enthalpy was 12 J / g, and crystallite size measured by wide-angle X-ray diffraction (XRD) was 12 nm)

[0077] (B) Hydrogenated block copolymer of aromatic vinyl compound and conjugated diene compound (B-1)S-EB / SS (Kraton A MD1537HU (trade name), manufactured by Kraton Corporation, proportion of styrene units in all constituent monomer units: 60 mass%, mass average molecular weight: 136,000) (B-2)SEEPS (SEPTON 4033 (product name), manufactured by Kuraray Co., Ltd., proportion of styrene units in all constituent monomer units: 30% by mass, mass average molecular weight: 100,000) (B-3) SEBS (TAIPOL6151 (trade name), manufactured by TSRC, proportion of styrene units in all constituent monomer units: 32% by mass, mass average molecular weight: 260,000) (B-4) SEBS (TAIPOL6159 (trade name), manufactured by TSRC, proportion of styrene units in all constituent monomer units: 30 mass%, mass average molecular weight: 390,000)

[0078] (C) Amine-modified block copolymer of aromatic vinyl compound and conjugated diene compound (C-1) Amine-modified hydrogenated block copolymer of styrene and 1,3-butadiene (Tuftec MP10 (product name), manufactured by Asahi Kasei Chemicals Corporation, proportion of styrene units in all constituent monomer units: 30 mass%, amount of amine modification: 0.06 mass%, mass average molecular weight: 50,000, number average molecular weight: 21,000) (C-2) Maleic acid modified hydrogenated block copolymer of styrene and 1,3-butadiene (Tuftec M1913 (trade name), manufactured by Asahi Kasei Chemicals Corporation, proportion of styrene units in all constituent monomer units: 30% by mass, amount of maleic acid modification: 2% by mass, mass average molecular weight: 91,000, number average molecular weight: 43,000)

[0079] (D) Non-aromatic rubber softeners (D-1) Paraffin oil (Diana Process Oil PW-90 (product name), Idemitsu Kosan Co., Ltd., mass average molecular weight 540, aromatic carbon number 0.1% or less, viscosity (37.8°C) 30.85 cSt, viscosity (100°C) 5.3 cSt, pour point -15°C, flash point 270°C)

[0080] The above-mentioned raw materials were mixed according to the composition shown in Table 1, and melt-kneaded using a twin-screw extruder (TEX-25αIII, manufactured by The Japan Steel Works, Ltd.) with an L / D ratio of 52.5 at a kneading temperature of 200°C and a screw rotation speed of 350 rpm, and then pelletized. The pellets obtained were used in an injection molding machine with a clamping force of 120 tons, with a resin temperature of 230°C, a mold temperature of 40°C, an injection speed of 55 mm / sec, and an injection pressure of 600 kg / cm. 2 , packing pressure 400 kg / cm 2 A sheet measuring 13.5 cm long x 13.5 cm wide x 2 mm thick was molded under the conditions of an injection time of 6 seconds and a cooling time of 15 seconds. The injection sheet obtained above was then heat pressed under the conditions of preheating at 220°C for 3 minutes and applying pressure at 220°C for 3 minutes to produce two types of pressed sheets with thicknesses of 1 mm and 6 mm. The sheets obtained as described above were subjected to the above-mentioned evaluations. The evaluation results are shown in Table 1.

[0081] [Table 1]

Claims

1. (A) a polyester-based thermoplastic elastomer; (B) a hydrogenated block copolymer of an aromatic vinyl compound and a conjugated diene compound, having a mass-average molecular weight of 350,000 or less; (C) an amine-modified block copolymer of an aromatic vinyl compound and a conjugated diene compound or an amine-modified product of a hydrogenated product of the block copolymer; and (D) non-aromatic rubber softener; A thermoplastic elastomer composition comprising:

2. The total of the components (A), (B), and (C) is 100% by mass, 40 to 85% by mass of the component (A); 10 to 45% by mass of the component (B); and 1 to 35% by mass of the component (C) The thermoplastic elastomer composition of claim 1, comprising:

3. 3. The thermoplastic elastomer composition according to claim 1, wherein the component (A) is a polyester-based thermoplastic elastomer composed of a crystalline phase mainly composed of an aromatic polyester and an amorphous phase mainly composed of an aliphatic polyether.

4. The thermoplastic elastomer composition according to any one of claims 1 to 3, wherein the component (A) is a polyester-based thermoplastic elastomer having a crystallization temperature of 130 to 160°C.

5. the component (B) is a hydrogenated product of a block copolymer having two or more polymer blocks (X) containing an aromatic vinyl unit as a structural unit and one or more copolymer blocks (Y) mainly composed of a conjugated diene monomer and an aromatic vinyl monomer as a structural unit; The thermoplastic elastomer composition according to any one of claims 1 to 4, wherein the copolymer block (Y) is a copolymer block mainly composed of ethylene, butylene, and styrene.

6. The thermoplastic elastomer composition according to any one of claims 1 to 5, wherein the component (C) is an amine-modified product of a hydrogenated block copolymer of an aromatic vinyl compound and a conjugated diene compound.

7. The thermoplastic elastomer composition according to any one of claims 1 to 6, wherein the thermoplastic elastomer composition has a haze of 70 or less when formed into a sheet having a thickness of 1 mm.

8. A grip material comprising the thermoplastic elastomer composition according to any one of claims 1 to 7.

9. A writing implement comprising the grip material of claim 8.

10. A tool comprising the gripping material of claim 8.

11. A ply rail made of the thermoplastic elastomer composition according to any one of claims 1 to 7.

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