resin composition

Abstract

The present invention provides a resin composition containing a thermoplastic elastomer that has excellent molding processability, such as flexibility, oil resistance, and two-color molding ability into a polar resin substrate, and a molded article. The present invention provides a hydrogenated block copolymer (A) obtained by hydrogenating a block copolymer having at least two or more polymer blocks (A) made of an aromatic vinyl compound in the molecule and one or more polymer blocks (B) made of a conjugated diene compound in the molecule, with respect to 100 parts by mass of the hydrogenated block copolymer (A). (b) Polyester elastomer 80 to 270 parts by mass (c) Rubber softener 50 to 270 parts by mass A resin composition comprising the above components, wherein the components (a) and (b) form a bicontinuous structure with macrophase separation, and the component (b) further forms a microphase separation structure. [Selected Figure] Figure 1

Description

[Technical Field]

[0001] The present invention relates to a thermoplastic elastomer resin composition and a molded article thereof, which have excellent molding processability such as flexibility, oil resistance, and two-color molding ability. [Background technology]

[0002] In recent years, thermoplastic elastomers, which are rubber-like soft materials that do not require a vulcanization process and have moldability similar to that of thermoplastic resins, have been attracting attention in fields such as automobile parts, industrial products, medical and food equipment parts, and miscellaneous goods. For example, polystyrene-based elastomers, which have excellent flexibility, are used for sealing parts, while urethane-based elastomers or polyester-based elastomers, which have excellent two-color moldability, are used for pen grip applications. Two-color molding is a molding method in which a resin such as an elastomer is simply inserted into a substrate during the injection molding process, causing the resin to fuse and become integrated with the substrate. Compared to conventional manufacturing methods in which separate resins and substrates are assembled separately (hereinafter referred to as assembly manufacturing methods), this manufacturing method simplifies the manufacturing process and reduces costs, while also imparting toughness and airtightness to the product. To be applicable to two-color molding, the resin must have affinity with the substrate resin. On the other hand, conventional resin compositions do not have materials that can be used in two-color molding and that are flexible and oil-resistant, so there are cases where an assembly manufacturing method has to be used. For example, polystyrene-based elastomers have excellent flexibility, but cannot be molded with polar resins such as ABS or PC. Silicone rubber, on the other hand, has excellent oil resistance and can be molded with two colors, but requires a secondary vulcanization process, which makes it difficult to simplify the manufacturing process or reduce costs. Polyester-based elastomers have excellent moldability, but are hard and lack flexibility.

[0003] In view of the above-mentioned problems, resin compositions that combine the advantages of resins such as polystyrene-based elastomers, silicone rubber, and polyester-based elastomers have been disclosed (see, for example, Patent Document 1). However, while the resin composition disclosed in Patent Document 1 has excellent flexibility, it does not have sufficient performance in terms of oil resistance or two-color moldability. When Patent Document 1 addresses the issue of two-color moldability onto polar resin substrates, a polar elastomer is an essential component. However, as the proportion of plasticizer or non-polar elastomer added to achieve flexibility increases, adhesion to the substrate deteriorates, making it difficult to achieve both two-color moldability and flexibility. Furthermore, the oil resistance in Patent Document 1 targets oleic acid, a component of sebum. Oleic acid and polar elastomers have a good affinity, but there is a problem in that the composition is susceptible to the deterioration of physical properties due to oleic acid. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Patent No. 2817879 Summary of the Invention [Problem to be solved by the invention]

[0005] An object of the present invention is to provide a resin composition containing a thermoplastic elastomer that has excellent moldability, such as flexibility, oil resistance to oleic acid, and two-color moldability onto a polar resin substrate, and a molded article thereof. [Means for solving the problem]

[0006] The present inventors have conducted extensive research to solve the above problems. , Yoshi Xiangzoku vinyl compounds and conjugated dienes compound The present inventors have found that by blending a hydrogenated derivative of a block copolymer of ethylenediaminetetraacetic acid and propylene glycol, a rubber softener, and a specific polyester elastomer at a specific ratio within a certain range, a resin composition having excellent molding processability, such as flexibility, oil resistance, and two-color moldability, can be obtained.

[0007] That is, the present invention provides a hydrogenated block copolymer (A) obtained by hydrogenating a block copolymer having at least two or more polymer blocks (A) made of an aromatic vinyl compound in the molecule and one or more polymer blocks (B) made of a conjugated diene compound in the molecule, with 80 to 250 parts by mass of (B) a polyester elastomer and (C) a rubber softener, 100 The present invention provides a resin composition comprising 270 parts by mass or less of a polymerizable compound, wherein component (A) and component (B) form a co-continuous structure with macrophase separation, and component (B) forms a microphase-separated structure; a molded article containing the resin composition; and a molded article comprising the resin composition and a hard resin, wherein at least a portion of the resin composition and the hard resin are heat-fused together. [Effects of the Invention]

[0008] The resin composition of the present invention has excellent moldability, such as flexibility, oil resistance to oleic acid, and two-color molding onto polar resin substrates, and therefore can provide airtightness and durability for various applications and can also be used in two-color molding manufacturing processes, thereby contributing to process simplification.The resin composition of the present invention is suitable for use in molded products such as grips, housings, rollers, cushions, button coverings, and sealants for pens, cameras, sporting goods, etc. [Brief explanation of the drawings]

[0009] [Figure 1] 1 is an electron microscope photograph showing a bicontinuous structure in which components (a) and (b) in the resin composition of the present invention are macrophase separated. [Figure 2] 1 is an electron microscope photograph showing the morphology (having a microphase separation structure) of component (b) in the resin composition of the present invention. [Figure 3] Electron microscope photograph showing the morphology (without microphase separation structure) of component (b) in a resin composition of the prior art (comparative example). DETAILED DESCRIPTION OF THE INVENTION

[0010] In the resin composition of the present invention, the hydrogenated block copolymer (A) component and the polyester elastomer (B) component form a macrophase-separated, co-continuous structure, and the polyester elastomer (B) component also has a microphase-separated structure. The presence or absence of a phase-separated structure can be determined by observing the morphology using a transmission electron microscope, as described below. Figure 1 shows an electron microscope photograph illustrating the state in which the hydrogenated block copolymer (A) component and the polyester elastomer (B) component form a macrophase-separated, co-continuous structure. Figures 2 and 3 show electron microscope photographs of the morphology of the polyester elastomer (B) component used in this example and this comparative example, respectively. The image of the polyester elastomer used in this example has contrast, indicating a phase-separated structure due to differences in functional group concentration. On the other hand, the image of the polyester elastomer used in this comparative example has no contrast and is in a single phase, indicating no phase separation. The present invention uses two or more types of polyester elastomers and utilizes the difference in functional group concentration between them to form a phase-separated polyester elastomer, thereby achieving a balance between flexibility, oil resistance, and moldability such as two-color moldability, which was not possible with conventional methods.

[0011] The hydrogenated block copolymer (A) used in the present invention is one obtained by hydrogenating a block copolymer having two or more polymer blocks (A) made of an aromatic vinyl compound and one or more polymer blocks (B) made of a conjugated diene compound in the molecule. Examples of aromatic vinyl compounds constituting the polymer block (A) include styrene, α-methylstyrene, 1-vinylnaphthalene, o-methylstyrene, m-methylstyrene, p-methylstyrene, 4-propylstyrene, 1,3-dimethylstyrene, 4-cyclohexylstyrene, 4-dodecylstyrene, 2-ethyl-4-benzylstyrene, 4-(phenylbutyl)styrene, vinylnaphthalene, and vinylanthracene. The polymer block (A) may be composed of one or more of the above aromatic vinyl compounds. In the present invention, the polymer block (A) is preferably composed of styrene and / or α-methylstyrene.

[0012] The number average molecular weight of the polymer block (A) is preferably in the range of 2500 to 80000, more preferably 10000 to 50000, and particularly preferably 20000 to 40000. If it is below 2500, the mechanical strength of the resulting thermoplastic resin composition may decrease, while if it exceeds 80000, the melt viscosity may become too high, resulting in poor mixability with other components of the present invention and poor moldability of the thermoplastic resin composition.

[0013] Examples of conjugated diene compounds constituting the polymer block (B) include 1,3-butadiene, isoprene, 1,3-pentadiene, 2,3-dimethyl-1,3-butadiene, 2-methyl-1,3-pentadiene, 1,3-hexadiene, phenylbutadiene, 4,5-diethyl-1,3-octadiene, and 3-butyl-1,3-octadiene. In the present invention, the polymer block (B) may be composed of one or more of these compounds. In the present invention, 1,3-butadiene and isoprene are preferably used as the conjugated diene compounds constituting the polymer block (B), particularly from the viewpoint of improving the rubber physical properties. The number-average molecular weight of the polymer block (B) is preferably in the range of 10,000 to 300,000, more preferably 20,000 to 250,000, and particularly preferably 30,000 to 170,000. If the molecular weight is less than 10,000, the elastic properties of the resulting thermoplastic resin composition may be impaired. On the other hand, if the molecular weight exceeds 300,000, the melt viscosity may become too high, resulting in poor mixability with other components of the present invention and poor moldability of the thermoplastic resin composition. The microstructure of the polymer block (B) of the hydrogenated block copolymer is not particularly limited. Therefore, the vinyl bond content in the polymer block (B) before hydrogenation, i.e., the 1,2-bond content when 1,3-butadiene is used, the 1,2-bond content and the 3,4-bond content when isoprene is used, and the vinyl bond content when 1,3-butadiene and isoprene are used in combination, are not limited within any range.

[0014] The content of the polymer block (A) made of an aromatic vinyl compound in the hydrogenated block copolymer (A) is in the range of 5 to 70 mass%, more preferably 10 to 40 mass%, and particularly preferably 10 to 30 mass% of the hydrogenated block copolymer (A). If the content exceeds 70 mass%, the hydrogenated block copolymer (A) becomes hard, and the flexibility of the thermoplastic resin composition is impaired, making it brittle. On the other hand, if the content is less than 5 mass%, the content of the polymer block (A) is so low that the mechanical strength of molded articles obtained from the thermoplastic resin composition is insufficient. The number-average molecular weight of the hydrogenated block copolymer (A) is in the range of 50,000 to 400,000, more preferably 50,000 to 300,000, and particularly preferably 50,000 to 250,000. If the number-average molecular weight of the hydrogenated block copolymer (A) is less than 50,000, the mechanical strength of the molded article obtained from the thermoplastic resin composition will be insufficient. On the other hand, if the number-average molecular weight of the hydrogenated block copolymer exceeds 400,000, the moldability of the resulting thermoplastic resin composition will be reduced. Note that the number-average molecular weight referred to in this specification is the molecular weight in terms of polystyrene determined by gel permeation chromatography (GPC). In addition, in the hydrogenated block copolymer (a), two or more types of copolymers differing in the proportion of the polymer block (A) portion, and / or the vinyl bond amount, and / or the number average molecular weight can be used in combination.

[0015] The hydrogenated block copolymer (a) has two or more polymer blocks (A) and one or more polymer blocks (B). There are no particular restrictions on the bonding mode of the blocks. For example, when polymer block (A) is represented by A and polymer block (B) is represented by B, a block copolymer represented by (AB)nA (n is an integer of 1 to 10) or when a residue of a coupling agent is represented by X, a hydrogenated block copolymer obtained by hydrogenating a block copolymer represented by (AB)mX (m is an integer of 2 to 15) can be preferably used. The hydrogenated block copolymer (A) may be linear, branched, or star-shaped, and there are no particular restrictions on the order of linkage of each block or the number of linked blocks. To control the microstructure of the polymer block (B), a cocatalyst may be used during polymerization. Examples of the cocatalyst include ethers such as dimethyl ether, diethyl ether, tetrahydrofuran, and dioxane; glycol ethers such as ethylene glycol dimethyl ether and diethylene glycol dimethyl ether; and amine compounds such as triethylamine, N,N,N',N'-tetramethylethylenediamine, and N-methylmorpholine. These may be used alone or in combination.

[0016] The hydrogenated block copolymer (A) used in the present invention may further contain functional groups such as carboxyl groups, hydroxyl groups, acid anhydrides, amino groups, and epoxy groups in the molecular chain or at the molecular terminals, as long as the purpose of the present invention is not impaired. Therefore, the hydrogenated block copolymer (A) used in the present invention may contain one type of hydrogenated block copolymer having such a functional group, or two or more types of hydrogenated block copolymers having such functional groups may be used in combination. Furthermore, a hydrogenated block copolymer having functional groups at the molecular terminals and / or in the molecular chain may be used in combination with a hydrogenated block copolymer not having such functional groups.

[0017] The hydrogenated block copolymer (A) can be obtained by any known method, including hydrogenating a polymer obtained by anionic polymerization, ionic polymerization methods such as cationic polymerization, Ziegler polymerization, single-site polymerization, and radical polymerization. For example, an aromatic vinyl compound and a conjugated diene compound are sequentially polymerized in an inert organic solvent such as n-hexane, cyclohexane, or octane using an alkyllithium compound such as methyllithium, ethyllithium, butyllithium, or pentyllithium as an initiator to form a block copolymer. This block copolymer is then hydrogenated in an inert organic solvent such as n-hexane, cyclohexane, or octane in the presence of a hydrogenation catalyst according to a known method, thereby hydrogenating at least 70 mol%, preferably at least 90 mol%, of the carbon-carbon double bonds derived from the conjugated diene compound to obtain the hydrogenated block copolymer (A). If the hydrogenation rate is less than 70 mol%, the expected improvement in heat resistance and weather resistance due to the hydrogenation may be insufficient. From the viewpoint of heat resistance and weather resistance, it is particularly preferable to hydrogenate 95 mol % or more of the unsaturated double bonds derived from the conjugated diene compound in the block copolymer before hydrogenation. The amount of carbon-carbon double bonds derived from the conjugated diene compound in the hydrogenated block copolymer (a) can be determined by iodine value measurement, infrared spectrophotometer, nuclear magnetic resonance spectrometer, etc. Examples of the hydrogenation catalyst include solid catalysts in which a metal such as nickel, platinum, palladium, ruthenium, or rhodium is supported on a substrate such as carbon, silica, or diatomaceous earth; homogeneous catalysts comprising an organometallic compound such as nickel or cobalt and an organoaluminum compound such as triethylaluminum or triisobutylaluminum; and homogeneous catalysts comprising a cyclopentadienyl compound of a transition metal such as titanium or haumium and an organometallic compound such as lithium, potassium, aluminum, zinc, or magnesium. As such hydrogenated block copolymer (a), commercially available products can be used, such as those available from Shell Chemical Industries, Ltd. under the trade name "Kraton," Asahi Chemical Industry Co., Ltd. under the trade name "Tuftec," and Kuraray Co., Ltd. under the trade names "Hybler" and "Septon."

[0018] The polyester elastomer (ii) used in the present invention refers to a thermoplastic resin composition composed of hard segments and soft segments. The hard segments are preferably polyesters composed of aromatic dicarboxylic acids and diols. The soft segments are preferably composed of aromatic dicarboxylic acids and poly(tetramethylene) glycol. In the polyester-based elastomer (ii) of the present invention, the aromatic dicarboxylic acid constituting the polyester hard segment is generally any of the commonly used aromatic dicarboxylic acids, but is not particularly limited thereto. Preferably, the primary aromatic dicarboxylic acid is terephthalic acid or naphthalenedicarboxylic acid. Other acid components include aromatic dicarboxylic acids such as diphenyldicarboxylic acid, isophthalic acid, and 5-sodium sulfoisophthalic acid; alicyclic dicarboxylic acids such as cyclohexanedicarboxylic acid and tetrahydrophthalic anhydride; and aliphatic dicarboxylic acids such as succinic acid, glutaric acid, adipic acid, azelaic acid, sebacic acid, dodecanedioic acid, dimer acid, and hydrogenated dimer acid. These acids are used in amounts that do not significantly lower the melting point of the resin, and the amount used is less than 30 mol %, preferably less than 20 mol %, of the total acid components.

[0019] In the polyester elastomer (ii) according to the present invention, the diol constituting the polyester of the hard segment is generally a common aliphatic or alicyclic diol, and is not particularly limited, but is preferably an alkylene glycol having 2 to 8 carbon atoms. Specific examples include ethylene glycol, 1,3-propylene glycol, 1,4-butanediol, 1,6-hexanediol, 1,4-cyclohexanedimethanol, and dimer glycol. Ethylene glycol, 1,4-butanediol, 1,4-cyclohexanedimethanol, and dimer glycol are preferred, with 1,4-butanediol being particularly preferred.

[0020] As the component constituting the polyester of the hard segment, those containing butylene terephthalate units or butylene naphthalate units are preferred from the viewpoints of physical properties, moldability and cost performance.

[0021] The aromatic polyester suitable for the hard segment of the polyester elastomer (ii) used in the present invention can be easily obtained by a conventional polyester production method, and preferably has a number average molecular weight of 10,000 to 80,000.

[0022] Furthermore, the number average molecular weight of the poly(tetramethylene) glycol, which is preferred as a component constituting the soft segment in the polyester-based elastomer (ii) used in the present invention, is desirably 500 to 4000 for the reasons described below. The preferred lower limit is 600, more preferably 800. Other poly(alkylene) glycols, aliphatic polyester glycols, etc. may also be used as part of the soft segment, as long as the properties of the present invention are not impaired.

[0023] The polyester elastomer (ii) according to the present invention is obtained by reacting a hard segment with a soft segment. The weight ratio of the soft segment is preferably 5 to 85% by weight, more preferably 40 to 80% by weight, at which point the elastomeric properties can be exhibited. The reaction can be carried out by arbitrarily determining the combination of reaction temperature, catalyst concentration, and reaction time. That is, the optimum reaction conditions vary depending on various factors, such as the type and ratio of the hard and soft segments used, the shape of the apparatus used, and the stirring conditions.

[0024] The polyester elastomer (b) used in the present invention may contain a small amount of a tri- or higher functional polycarboxylic acid or polyol, such as trimellitic anhydride, benzophenone tetracarboxylic acid, trimethylolpropane, or glycerin.

[0025] Next, any known method can be used to obtain the polyester elastomer (b) of the present invention. For example, melt polymerization, solution polymerization, solid-state polymerization, or the like can all be used as appropriate. In the case of melt polymerization, either transesterification or direct polymerization may be used. Suitable catalysts for the reaction include antimony catalysts, germanium catalysts, and titanium catalysts. Titanium catalysts are particularly preferred, and more specifically, tetraalkyl titanates such as tetrabutyl titanate and tetramethyl titanate, and metal oxalates such as potassium titanium oxalate are preferred. Other known catalysts are not particularly limited, but include tin compounds such as dibutyltin oxide and dibutyltin dilaurate, and lead compounds such as lead acetate. Furthermore, for the polyester-based elastomer (ii), two or more types of aromatic dicarboxylic acid components constituting the polyester of the hard segments and soft segments, and / or low-molecular-weight glycol components constituting the polyester of the hard segments and soft segments, and / or polyester elastomers differing in weight ratio of the soft segments in the polyester elastomer can be used in combination. As such polyester-based elastomer (b), commercially available products can be used, such as "Pelprene" (trade name) from Toyobo Co., Ltd. and "Hytrel" (trade name) from Toray DuPont Co., Ltd.

[0026] The rubber softener (c) used in the present invention can be any known softener without any particular limitation. Examples include hydrocarbon oils such as paraffinic, naphthenic, aromatic, and liquid paraffin; vegetable oils such as peanut oil and rosin; phosphate esters; chlorinated paraffin; silicone oil; liquid polyisoprene or hydrogenated polyisoprene; liquid polybutadiene; liquid polyisobutylene; and modified polymers thereof. One or more plasticizers may be used. Commercially available plasticizers are also available. For example, paraffinic oils available from Idemitsu Kosan Co., Ltd. under the trade names "Diana Process Oil PW-380," "Diana Process Oil PW-90," and "Diana Process Oil PW-32" are available.

[0027] The present invention provides a resin composition comprising 80 to 270 parts by mass, preferably 90 to 180 parts by mass, and more preferably 100 to 150 parts by mass of a polyester elastomer as component (ii), and 50 to 270 parts by mass, preferably 100 to 190 parts by mass, and more preferably 140 to 180 parts by mass of a rubber softener as component (iii), relative to 100 parts by mass of a hydrogenated block copolymer (ii) obtained by hydrogenating a block copolymer having at least two or more polymer blocks (A) composed of an aromatic vinyl compound in the molecule and one or more polymer blocks (B) composed of a conjugated diene compound in the molecule. The resin composition has a microphase-separated structure confirmed by the appearance of light and dark areas in the polyester elastomer phase when morphology is observed using a transmission electron microscope as described below. If the amount of polyester elastomer (b) exceeds 270 parts by mass, flexibility may be poor, and if it is less than 80 parts by mass, adhesiveness may be poor. If the amount of the rubber softener (c) exceeds 270 parts by mass, the adhesiveness may be poor, and if it is less than 50 parts by mass, the flexibility may be poor.

[0028] Other components can be added to the resin composition of the present invention as long as they do not impair the effects of the present invention. For example, modified products of the hydrogenated block copolymer (A), copolymers such as acrylate-styrene, styrene-based resins, olefin resins, polyoxymethylene resins, polyphenylene ether resins, etc. can be blended. In addition, inorganic fillers can also be added. In particular, graft and block copolymers with hydrophilic polymers are known to function as compatibilizers between the hydrogenated block copolymer (A) and the polyester elastomer (B), thereby improving performance. Specific examples of such inorganic fillers include talc, calcium carbonate, barium sulfate, kaolin, and titanium oxide.

[0029] The thermoplastic resin composition used in the present invention may contain, for the purpose of modifying it, glass fibers, carbon fibers, flame retardants (ammonium polyphosphate compounds, phosphate esters, condensed phosphate esters, etc.), blowing agents (azodicarbonamide, dinitrosopentamethylenetetramine, etc.), antioxidants and heat stabilizers (hindered phenols, hydroquinones, phosphites, and their substituted derivatives, etc.), light stabilizers, ultraviolet absorbers and weathering agents (resorcinols, salicylates, benzotriazoles, benzophenones, hindered amines, etc.), mold release agents and lubricants (montanic acid and its gold). Other additives that can be added include metal salts, their esters, their half esters, stearyl alcohol, stearamide, various bisamides, bisurea, polyethylene wax, etc.), pigments (cadmium sulfide, phthalocyanine, carbon black, etc.), dyes (nigrosine, etc.), crystal nucleating agents (talc, silica, kaolin, organic acid salts, clay, etc.), ionomers, antistatic agents (alkyl sulfate-type anionic antistatic agents, quaternary ammonium salt-type cationic antistatic agents, nonionic antistatic agents such as polyoxyethylene sorbitan monostearate, betaine-based amphoteric antistatic agents, etc.).

[0030] The thermoplastic resin composition used in the present invention can be produced by a method commonly used in the production of resin compositions or elastomer compositions, and the above components are mixed using a melt kneader such as a single-screw extruder, a twin-screw extruder, a Banbury mixer, a heated roll, various kneaders, etc. There are no particular limitations on the melt temperature as long as melting and kneading are possible, but it is generally 150 to 240°C, more preferably 180 to 220°C.

[0031] The present invention provides a molded article comprising the above-described resin composition. The resin composition of the present invention can be used to produce a molded article by any molding method, such as extrusion molding, press molding, injection molding, vacuum molding, film molding, or blow molding, and can also be used to produce a molded article in which the resin composition and the hard resin are at least partially heat-fused by two-color molding with the hard resin, such as ABS or PC (polycarbonate). As the hard resin, AS resin, ABS resin, PET (polyethylene terephthalate) resin, PBT (polybutylene terephthalate) resin, PMMA (polymethacrylic) resin, PC (polycarbonate) resin, etc. can be used.

[0032] Molded articles containing the resin composition of the present invention can be used for automobile parts, home appliance parts, medical and food equipment parts, seats, miscellaneous goods, industrial materials, grips, cushions, pads, and the like. [Example]

[0033] The present invention will be described in detail below with reference to examples, but the present invention is not limited to these examples. In the following examples and comparative examples, measurements or evaluations of hardness, oil resistance, adhesive strength, and morphology observation were carried out as follows.

[0034] <Creating evaluation samples> A resin composition was obtained by melt-kneading using a twin-screw extruder at a barrel temperature of 220°C. The resulting resin composition was injection molded at an injection temperature of 230°C and a mold temperature of 40°C to obtain an evaluation sample with a thickness of 2 mm. The injection molding machine used was a 120t injection molding machine manufactured by Nissei Plastic Industrial Co., Ltd.

[0035] (1) Hardness: Measured in accordance with JIS K 6253, a hardness of 70A or less was evaluated as having flexibility. (2) Oil resistance: Measured in accordance with JIS K 6258. The test piece (2 cm wide x 5 cm long x 2 mm thick) was placed in an environment of 23°C x 50% RH. After immersion in phosphoric acid for one week, the weight change rate and the presence or absence of color change were evaluated by visual observation. The required performance was determined to be a weight change of 60% or less and no change in color tone. (3) Adhesive strength: Measured in accordance with JIS K 6256. The resin composition obtained by melt-kneading was applied to a 25 mm wide polycarbonate substrate at 230°C. The resin is injected at the resin temperature to create a two-color molded adhesive sample. The injection molding machine is a 120 model manufactured by Nissei Plastics Co., Ltd. The adhesive samples were then subjected to tensile testing at a tensile speed using an Instron universal testing machine. A peel test was carried out at a rate of 5 cm / min, and the adhesive strength (N / 25 mm) was measured. The required performance is an adhesive strength of 50 (N / 25 mm) or more.

[0036] (4) Morphology observation using TEM Ultrathin sections with a thickness of 85 nm were prepared for TEM observation using a Leica ultramicrotome (model: Ultracut S / FC-S). The ultrathin sections were collected on a copper mesh. The ultrathin sections were then vapor stained using an aqueous solution of RuO4. For structural observation, a transmission electron microscope (model: HT7700, 3DTEM compatible) manufactured by Hitachi High-Technologies Corporation equipped with an LaB6 electron gun was used. Morphology observation was carried out under the conditions of an accelerating voltage of 100 KV, LaB6 electron beam irradiation dose of 10 μA, and electron beam spot size of 1 μm. The CCD camera used for recording images was an AMT bottom-mount camera (model: XR81B, 8 megapixel camera).

[0037] The polyester elastomer used in the present invention has a microphase-separated structure due to differences in functional group concentration, and therefore, when observed for morphology, light and dark appear. The microphase-separated structure was evaluated by assessing whether or not the light and dark appeared. Furthermore, when the contrast value difference was 30 or more using the image analysis method described below, it was determined that the microphase-separated structure was present. <Image analysis method> Image analysis was performed using image processing software WinROOF (Version 7) manufactured by Mitani Corporation. Using the image processing item "Density Features" in WinROOF, the degree of brightness within the polymer phase in the raw data of the TEM observation images was expressed in 256 gradations and quantified. The image processing range for the bright and dark areas of the TEM image was specified by a dotted frame. The image processing range was set to 150 pixels horizontally and 150 pixels vertically, and a total of 22,500 pixels were evaluated, and the contrast difference was calculated from the average brightness value.

[0038] The components used in Examples 1 to 6 and Comparative Examples 1 to 6 are as follows: (a) Ingredients; Kuraray's "Septon 8006" was used as a hydrogenated derivative of a block copolymer of monovinyl-substituted aromatic hydrocarbon and conjugated diene. (b) Ingredients; The polyester elastomers used are "Hytrel 3046," "Hytrel 4047N," and "Hytrel 7247" manufactured by Toray DuPont. (c) Ingredients; Idemitsu Kosan's "PW-32" is used as a rubber softener.

[0039] [Table 1]

[0040] [Table 2]

[0041] From the above results, it can be seen that the required performance of oil resistance, which is confirmed to be flexibility of 70A or less in hardness, adhesive strength of 50N / 25mm or more, weight change rate of 60% or less, and no change in color tone, is satisfied in the Examples because the polyester elastomer component has a microphase separation structure. However, the Comparative Examples were unable to satisfy these required performances.

Claims

1. per 100 parts by mass of a hydrogenated block copolymer (A) obtained by hydrogenating a block copolymer having at least two or more polymer blocks (A) made of an aromatic vinyl compound in the molecule and one or more polymer blocks (B) made of a conjugated diene compound in the molecule, (b) 80 to 150 parts by mass of polyester elastomer (c) 100 to 270 parts by mass of rubber softener In the resin composition containing the above, the component (a) and the component (b) form a macrophase-separated bicontinuous structure, and further (b) component contains two or more polyester elastomers having different functional group concentrations; the polyester elastomer is composed of a hard segment consisting of an aromatic dicarboxylic acid and a diol and a soft segment consisting of an aromatic dicarboxylic acid and poly(tetramethylene) glycol; The polyester elastomer comprises an aromatic dicarboxylic acid component constituting a polyester of hard segments and soft segments, and / or a low-molecular-weight glycol component constituting a polyester of hard segments and soft segments, and / or two or more types of polyester elastomers having different weight ratios of soft segments in the polyester elastomer; (b) A resin composition characterized by forming a microphase-separated structure in which the contrast difference derived by the <Image analysis method> described below when the component (b) is observed by the <Morphology observation by TEM> described below is 30 or more. <Morphology observation using TEM> Ultrathin sections with a thickness of 85 nm were prepared for TEM observation using a Leica ultramicrotome (model: Ultracut S / FC-S). The ultrathin sections were collected on a copper mesh. Ultrathin sections were steam stained using the 4 aqueous solution. For structural observation, a transmission electron microscope (model: HT7700, 3DTEM compatible) manufactured by Hitachi High-Technologies Corporation equipped with an LaB6 electron gun was used. Morphology observation was carried out under the conditions of an acceleration voltage of 100 KV, LaB6 electron beam irradiation dose of 10 μA, and electron beam spot size of 1 μm. The CCD camera used for recording images was an AMT bottom-mount camera (model: XR81B, 8 megapixel camera). <Image analysis method> Image analysis was performed using image processing software WinROOF (Version 7) manufactured by Mitani Corporation. Using the image processing item "Density Features" in WinROOF, the degree of brightness within the polymer phase in the raw data of the TEM observation images was expressed in 256 gradations and quantified. The image processing range for the bright and dark areas of the TEM image was specified by a dotted frame. The image processing range was set to 150 pixels horizontally and 150 pixels vertically, and a total of 22,500 pixels were evaluated, and the contrast difference was calculated from the average brightness value.

2. A molded article comprising the resin composition of claim 1.

3. A molded article comprising the resin composition according to claim 1 and a hard resin, wherein the resin composition and the hard resin are at least partially heat-sealed.

Images