Elastomer composition and molded body

Abstract

Provided is an elastomer composition and the like comprising: an aromatic vinyl compound-based elastomer (A); an oil (Y) having a kinematic viscosity at 40°C of less than 50 mm2 / sec; and an organic additive (Z) soluble in the oil (Y) at 160°C. The amount of the oil (Y) per 100 parts by mass of the aromatic vinyl compound-based elastomer (A) is in the range of 500-4,000 parts by mass, and the content of the organic additive (Z) in the elastomer composition is 0.5 mass% or more. The elastomer composition satisfies the requirement that an actual precipitation amount P is greater than 0 if a 2.34 mass% solution of the organic additive (Z) obtained using a specific solvent is heated to 50°C ±5°C over 30 minutes.

Description

Elastomer composition and molded article

[0001] The present invention relates to elastomer compositions and molded articles.

[0002] Molded articles formed from elastomer compositions containing elastomers and softeners are used in a variety of applications.

[0003] For example, Patent Document 1 contains a styrene-based elastomer, a mineral oil-based softener, and a particulate additive which is a particulate material surface-treated with a higher fatty acid, wherein the styrene-based elastomer has a weight-average molecular weight of 150,000 to 300,000, and the mineral oil-based softener has a kinematic viscosity of 50 mm at 40°C. ２ / s ~ 150mm ２ The present invention describes an elastomer composition in which the mineral oil-based softener is present in a blending ratio of 1250 to 1800 parts by mass and 60 to 170 parts by mass of the particulate additive, with a hardness of / s relative to 100 parts by mass of the styrene-based elastomer. Patent Document 1 states that, according to the technology described in Patent Document 1, an elastomer composition is provided that has extremely low hardness while having excellent mold release properties and heat resistance.

[0004] Japanese Patent Publication No. 2018-080224

[0005] In the technology described in Patent Document 1, in order to suppress the volatilization of the softening agent, the kinematic viscosity at 40°C is 50 mm². ２ It is necessary to use a softening agent with a concentration of / s. Furthermore, in the technology described in Patent Document 1, in order to retain mineral oil-based softening agents that cannot be fully retained by styrene-based elastomers alone in the elastomer composition, that is, in order to suppress oil bleed-out (hereinafter also simply referred to as "bleed-out"), it is necessary to use particulate additives surface-treated with higher fatty acids, specifically inorganic compounds such as magnesium hydroxide surface-treated with oleic acid.

[0006] However, as a result of our research, we have found that an elastomer composition containing an aromatic vinyl compound elastomer has a kinematic viscosity of 50 mm at 40°C. ２It has been found that incorporating oils with a viscosity of 1 / s or higher can result in poor processability of the molded product. Furthermore, there is a need for alternative technologies that can suppress oil bleed-out without using inorganic compounds.

[0007] Here, bleed-out is a phenomenon that occurs over time after molding, but it is particularly noticeable in the short period of about one week immediately after molding. Therefore, if bleed-out can be suppressed, it is expected that the time from immediately after molding to delivery can be shortened, or that the use of powder to suppress stickiness caused by bleed-out oil can be eliminated or reduced.

[0008] Therefore, if processability for molded articles is ensured and bleed-out is suppressed, it can be said that the elastomer composition has excellent moldable article manufacturability.

[0009] This invention has been made in view of the above circumstances, and aims to provide an elastomer composition that is excellent in terms of molded article manufacturability and a molded article formed from the elastomer composition.

[0010] The inventors of the present invention have conducted extensive research to achieve the above objectives and have found that the present invention can solve the problem as described below. That is, the present invention provides the following [1] to

[11] .

[0011] [1] An elastomer composition comprising an aromatic vinyl compound elastomer (A) and having a kinematic viscosity of 50 mm at 40°C. ２ The elastomer composition comprises an oil (Y) with a concentration of less than 1 / s and an organic additive (Z) soluble in the oil (Y) at 160°C, wherein the amount of the oil (Y) per 100 parts by mass of the aromatic vinyl compound elastomer (A) is in the range of 500 parts by mass to 4000 parts by mass, and the content of the organic additive (Z) in the elastomer composition is 0.5% by mass or more, and the organic additive (Z) has the following requirements: the mass S of the second solid when a 2.34% by mass solution of the organic additive (Z) using a specific solvent at 160°C that may contain a first solid is brought to 50°C ± 5°C over 30 minutes. ５０ From the mass S of the first solid component１６０ The substantial precipitation amount P that can be calculated by subtraction is greater than 0, where the specific solvent has a CAS registration number of 8042-47-5 and a kinematic viscosity at 40 °C of 10.8 to 13.6 mm ２ / s and a specific gravity of 0.829 to 0.859 white mineral oil, satisfying an elastomer composition. [2] The amount of the organic additive (Z) with respect to 1 part by mass of the oil (Y) is 0.008 part by mass or more, the elastomer composition according to [1]. [3] The mass S of the first solid content １６０ is 0, the elastomer composition according to [1] or [2]. [4] The organic additive (Z) is a polar group-containing organic compound, the elastomer composition according to any one of [1] to [4]. [5] The polar group-containing organic compound has four or more polar groups per molecule, the elastomer composition according to [4]. [6] The polar group-containing organic compound is at least one selected from phenolic hydroxyl group-containing organic compounds and their radical reaction products, the elastomer composition according to [4] or [5]. [7] The phenolic hydroxyl group-containing organic compound has two or more phenolic hydroxyl groups per molecule, the elastomer composition according to [6]. [8] The organic additive (Z) contains at least one selected from pentaerythritol tetrakis(3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate) and its radical reaction products, the elastomer composition according to any one of [1] to [7]. [9] The content of the organic additive (Z) in the elastomer composition is 10% by mass or less, the elastomer composition according to any one of [1] to [8].

[10] The aromatic vinyl compound-based elastomer (A) is a styrene-ethylene-ethylene-propylene-styrene copolymer, the elastomer composition according to any one of [1] to [9].

[11] A molded body formed of the elastomer composition according to any one of [1] to

[10] .

[0012] According to the present invention, an elastomer composition excellent in molded body productivity and a molded body formed of the elastomer composition can be provided.

[0013] Hereinafter, an example of an embodiment of the present invention (hereinafter sometimes referred to as "this embodiment") will be described. However, the embodiments shown below are examples for embodying the technical idea of the present invention, and the present invention is not limited to the following description.

[0014] In this specification, preferred forms of the embodiments are shown, but those obtained by combining two or more of the individual preferred forms are also preferred forms. For matters shown in numerical ranges, when there are several numerical ranges, the lower limit value and the upper limit value thereof can be selectively combined to form a preferred form. In this specification, when a numerical range is described as "XX to YY", it means "XX or more and YY or less". Further, in this specification, "~ unit" (where "~" represents a monomer) means "structural unit derived from ~", for example, "dicarboxylic acid unit" means "structural unit derived from dicarboxylic acid", and "diamine unit" means "structural unit derived from diamine compound". Also, "white mineral oil" is also called "liquid paraffin" or simply "mineral oil".

[0015] [Elastomer composition] One embodiment of the present invention is an elastomer composition. The elastomer composition of this embodiment includes an aromatic vinyl compound-based elastomer (A), an oil (Y) having a kinematic viscosity at 40°C of less than 50 mm ２ / s, and an organic additive (Z) soluble in the oil (Y) at 160°C. The amount of the oil (Y) relative to 100 parts by mass of the aromatic vinyl compound-based elastomer (A) is within the range of 500 parts by mass to 4000 parts by mass. The content of the bleed-out inhibitor (Z) in the compound resin composition is 0.5% by mass or more. The organic additive (Z) satisfies the following requirements: the mass S of the second solid content when a solution of 2.34% by mass of the organic additive (Z) using a specific solvent at 160°C that may contain a first solid content is brought to 50°C ± 5°C over 30 minutes. ５０ Subtracting the mass S of the first solid content from １６０ results in a substantial precipitation amount P that is greater than 0. Here, the specific solvent has a CAS registration number of 8042-47-5 and a kinematic viscosity at 40°C of 10.8 to 13.6 mm ２This is an elastomer composition that satisfies the conditions of being a white mineral oil with a specific gravity of 0.829 to 0.859 and a specific gravity of 0.829 to 0.859.

[0016] Here, the kinematic viscosity at 40°C can be measured by a method in accordance with ASTM D445-21, specifically by the method described in the Examples section.

[0017] Whether an organic additive (Z) is soluble in the oil (Y) at 160°C can be confirmed by heating 100 parts by mass of oil (Y) to 160°C and determining whether 2.4 parts by mass or more of the organic additive (Z) dissolves in the oil (Y). Specifically, this can be measured by the method described in the Examples section. For example, with respect to a molded body, if the oil contained in the molded body has a kinematic viscosity of 50 mmHg at 40°C... ２ If it is found that the oil (Y) is less than / s, alternatively, it may be checked whether the organic additive contained in the molded product is soluble in the aforementioned specific solvent (white mineral oil). If it is found to be soluble, the organic additive can be considered to be the organic additive (Z) as defined herein.

[0018] The aforementioned specific solvent has a kinematic viscosity of 50 mm at 40°C. ２ This is a typical example of an oil (Y) with a viscosity of less than / s. This particular solvent is typically available as a white mineral oil manufactured by Sonneborn, under the trade name "CARNATION®" (CAS registration number 8042-47-5).

[0019] The specific gravity can be measured in accordance with ASTM D4052-22, specifically by the method described in the Examples section.

[0020] A "solution of 2.34% by mass of organic additive (Z) using a specific solvent at 160°C that may contain a first solid component" can be prepared by adding 2.4 parts by mass of organic additive (Z) to 100 parts by mass of the specific solvent at 160°C and mixing, and specifically by the method described in the Examples section. In such a solution, if the organic additive (Z) is completely dissolved in the specific solvent, it means that the solution has a concentration of 2.34% by mass. If it contains a first solid component, it does not mean that the solution has a concentration of 2.34% by mass, but rather that the total mass of the dissolved component and the first solid component (undissolved component) relative to 100 parts by mass of the specific solvent is 2.4 parts by mass. However, since it must be a solution, the mass of the dissolved component is not 0.

[0021] "The mass S of the first solid component" １６０ " and "the mass S of the second solid component ５０ The first solid can be identified by filtering the solution and weighing the solid content. The unit of mass is usually grams. However, if the weighing is done by volume, the mass may be calculated by converting from the specific gravity. Mass S of the first solid content １６０ If it is zero (i.e., in the case of total dissolution), then "the actual amount of precipitate P is greater than 0 parts by mass" means that precipitate was formed in the solution at 50 ± 5°C. The mass S of the first solid component. １６０ When is zero, if precipitates are formed in the solution at 50±5℃, it is clear that "the actual precipitate amount P is greater than 0 parts by mass", therefore the mass S of the second solid component ５０ It is not necessary to specify it.

[0022] As mentioned above, the "actual precipitate amount P" is the mass S of the second solid component. ５０ Therefore, the mass S of the first solid component １６０ It can be calculated by subtracting the effective precipitate amount P. The unit of the effective precipitate amount P is usually grams. It is sufficient to know that the aforementioned condition "the effective precipitate amount P is greater than 0" is met, so calculation is not necessarily required. To give the first example, the mass S of the first solid component. １６０ If it is zero, there is no need to calculate the actual amount of precipitate P. Therefore, preferably, the mass S of the first solid component. １６０The result is zero (i.e., all 2.4 parts by mass of the organic additive dissolves in 100 parts by mass of a specific solvent at 160°C). To give a second example, if the first solid content in the solvent maintained at 160°C and the second solid content in the solvent at 50°C ± 5°C can be visually or optically compared, then it is not necessary to calculate the actual precipitate amount P.

[0023] According to this embodiment, it is possible to provide an elastomer composition with excellent moldability and a molded article formed from the elastomer composition. The reason for this effect is not clear, but the kinematic viscosity at 40°C is 50 mmHg. ２ By using an oil (Y) with a viscosity of less than 0.0 / s, the processability of the molded product is improved, and the aromatic vinyl compound elastomer (A) has a kinematic viscosity of 50 mm at 40°C. ２ In a system containing oil (Y) with a viscosity of less than / s in the aforementioned proportions, it is possible that the organic additive (Z) functioned as a bleed-out inhibitor due to the specific amount of the added organic additive (Z).

[0024] <Aromatic vinyl compound elastomer (A)> The elastomer composition of this embodiment includes aromatic vinyl compound elastomer (A). Aromatic vinyl compound elastomer (A) may be used alone or in combination of two or more types. Aromatic vinyl compound elastomer (A) includes aromatic vinyl compound units (a1). Aromatic vinyl compound units (a1) refer to structural units derived from aromatic vinyl compounds. The aromatic vinyl compound units (a1) contained in aromatic vinyl compound elastomer (A) may be used alone or in combination of two or more types.

[0025] The aromatic vinyl compound elastomer (A) may or may not contain structural units (b1) other than the aromatic vinyl compound unit (a1). From the viewpoint of lowering the hardness of the molded article, it is preferable that the aromatic vinyl compound elastomer (A) contains structural units (b1). One type of structural unit (b1) may be used alone, or two or more types may be used in combination.

[0026] When the aromatic vinyl compound elastomer (A) contains aromatic vinyl compound units (a1) and structural units (b1), the aromatic vinyl compound elastomer (A) may be a random copolymer, an alternating copolymer, a graft copolymer, or a block copolymer. In one preferred embodiment of this model, the aromatic vinyl compound elastomer (A) is a block copolymer.

[0027] A structural unit (b1) is a conjugated diene compound unit (b1-1). A conjugated diene compound unit refers to a structural unit derived from a conjugated diene compound. By including a conjugated diene compound unit (b1-1) in the aromatic vinyl compound elastomer (A), the hardness of the molded article can be reduced.

[0028] A preferred example of an aromatic vinyl compound elastomer (A) is a styrene elastomer. A styrene elastomer is an elastomer that contains structural units derived from styrene.

[0029] Specific examples of styrene-based elastomers include styrene-ethylene-styrene block copolymer (SEP), styrene-ethylene-propylene-styrene block copolymer (SEPS), styrene-ethylene-ethylene-propylene-styrene block copolymer (SEEPS), styrene-ethylene-butylene-styrene block copolymer (SEBS), and styrene-butadiene-styrene block copolymer (SBS), and styrene-isoprene-styrene block copolymer (SIS). Of these, SEPS, SEEPS, and SEBS are preferred from the viewpoint of improving the oil retention capacity of the elastomer composition and its molded articles, and SEEPS is more preferred.

[0030] In a preferred embodiment of this model, the aromatic vinyl compound-based elastomer (A) includes a hydrogenated block copolymer (X) which is a block copolymer (X') having a polymer block (a) mainly composed of structural units derived from an aromatic vinyl compound and a polymer block (b) mainly composed of structural units derived from a conjugated diene compound, with at least one terminal being composed of the polymer block (a). This hydrogenated block copolymer (X) will be described below.

[0031] <Hydrogenated Block Copolymer (X)> The aromatic vinyl compound elastomer (A) preferably contains a hydrogenated block copolymer (X). This allows the molded article to be imparted with one or more properties selected from, for example, oil absorption (excellent oil retention), elasticity, and durability. The polymer blocks (a) and polymer blocks (b) constituting the block copolymer (X') will be described in order below.

[0032] (Polymer block (a)) Polymer block (a) mainly consists of structural units derived from aromatic vinyl compounds. Here, "mainly consists of" means that polymer block (a) contains 50% by mass or more of structural units derived from aromatic vinyl compounds based on its total mass. From the viewpoint of transparency and mechanical strength of the molded article, the content of structural units derived from aromatic vinyl compounds in polymer block (a) is preferably 70% by mass or more, and more preferably 90% by mass or more, based on the total mass of polymer block (a). The upper limit is 100% by mass.

[0033] Examples of the above aromatic vinyl compounds include styrene, o-methylstyrene, α-methylstyrene, p-methylstyrene, α-methylstyrene, β-methylstyrene, 2,6-dimethylstyrene, 2,4-dimethylstyrene, α-methyl-o-methylstyrene, α-methyl-α-methylstyrene, α-methyl-p-methylstyrene, β-methyl-o-methylstyrene, β-methyl-α-methylstyrene, β-methyl-p-methylstyrene, 2,4,6-trimethylstyrene, α-methyl-2,6-dimethylstyrene, α-methyl-2,4-dimethylstyrene, β-methyl-2,6-dimethylstyrene, β-methyl-2,4-dimethylstyrene, o-chlorostyrene, α-chlorostyrene, p-chlorostyrene, 2,6-dichlorostyrene, 2,4-dichlorostyrene, α-chloro-o-chlorostyrene, Examples include α-chloro-m-chlorostyrene, α-chloro-p-chlorostyrene, β-chloro-o-chlorostyrene, β-chloro-m-chlorostyrene, β-chloro-p-chlorostyrene, 2,4,6-trichlorostyrene, α-chloro-2,6-dichlorostyrene, α-chloro-2,4-dichlorostyrene, β-chloro-2,6-dichlorostyrene, β-chloro-2,4-dichlorostyrene, o-t-butylstyrene, m-t-butylstyrene, p-t-butylstyrene, o-methoxystyrene, m-methoxystyrene, p-methoxystyrene, o-chloromethylstyrene, m-chloromethylstyrene, p-chloromethylstyrene, o-, m- or p-bromomethylstyrene, styrene derivatives substituted with silyl groups, indene, vinylnaphthalene, vinylanthracene, N-vinylcarbazole, and the like.

[0034] In particular, from the viewpoint of balancing manufacturing cost and physical properties, at least one selected from the group consisting of styrene and α-methylstyrene is preferred, with styrene being more preferred.

[0035] However, the polymer block (a) may contain structural units derived from unsaturated monomers other than aromatic vinyl compounds, as long as this does not interfere with the objectives and effects of the present invention. Examples of such other unsaturated monomers include at least one selected from butadiene, isoprene, 2,3-dimethyl-1,3-butadiene, 1,3-pentadiene, 1,3-hexadiene, isobutylene, methyl methacrylate, methyl vinyl ether, β-pinene, 8,9-p-menthene, dipentene, methylenenorbornene, and 2-methylenetetrahydrofuran. When the polymer block (a) contains such other unsaturated monomer units, the bonding configuration is not particularly limited and may be random or tapered.

[0036] The content of structural units derived from unsaturated monomers other than aromatic vinyl compounds in polymer block (a) is usually preferably 30% by mass or less, and more preferably 10% by mass or less, based on the total mass of polymer block (a).

[0037] The number-average molecular weight of polymer block (a) is not particularly limited, but is preferably 2,500 to 100,000, more preferably 5,000 to 50,000, and even more preferably 5,000 to 40,000. The above number-average molecular weight is the number-average molecular weight per polymer block. All "number-average molecular weight" as described herein is the number-average molecular weight on a standard polystyrene basis, determined by gel permeation chromatography (GPC) measurement.

[0038] Furthermore, the content of polymer block (a) in block polymer (X') is preferably 5 to 40% by mass, more preferably 10 to 35% by mass, and even more preferably 15 to 35% by mass, from the viewpoint of excellent tensile properties and low hardness. The content of polymer block (a) in block polymer (X') is １ This value was obtained by 1H-NMR spectroscopy. Furthermore, if a block polymer (X') has multiple polymer blocks (a), the "polymer block (a) content" refers to the total content of all polymer blocks (a).

[0039] (Polymer block (b)) Polymer block (b) mainly consists of structural units derived from conjugated diene compounds. Here, "mainly consists of" means that polymer block (b) contains 50% by mass or more of structural units derived from conjugated diene compounds based on the total mass of polymer block (b). The content of structural units derived from conjugated diene compounds in polymer block (b) is preferably 70% by mass or more, and more preferably 90% by mass or more, based on the total mass of polymer block (b). The upper limit is 100% by mass.

[0040] Examples of conjugated diene compounds constituting polymer block (b) include at least one selected from butadiene, isoprene, 2,3-dimethyl-1,3-butadiene, 1,3-pentadiene, 1,3-hexadiene, etc. Among these, at least one selected from the group consisting of butadiene and isoprene is preferred, and two types, butadiene and isoprene, are more preferred. When the conjugated diene compounds constituting polymer block (b) are two types, butadiene and isoprene, there are no particular restrictions on the ratio of the two, but preferably the molar ratio of butadiene to isoprene is in the range of 1 / 99 to 99 / 1, more preferably 10 / 90 to 90 / 10, and even more preferably 30 / 70 to 70 / 30.

[0041] Furthermore, if the polymer block (b) is composed of structural units derived from two or more conjugated diene compounds (e.g., butadiene and isoprene), there are no particular restrictions on their bonding configuration, and they can consist of random, tapered, perfectly alternating, partially blocky, blocky, or a combination of two or more of these.

[0042] The number-average molecular weight of polymer block (b) is not particularly limited, but from the viewpoint of lowering the hardness of the molded article, it is preferably 10,000 to 300,000, more preferably 20,000 to 270,000, and even more preferably 40,000 to 240,000. The above number-average molecular weight is the number-average molecular weight per polymer block.

[0043] In polymer block (b), the content of vinyl bonded structural units (for example, 1,2-bonded structural units in the case of butadiene monomers, and the sum of 1,2-bonded structural units and 3,4-bonded structural units in the case of isoprene monomers) is preferably 50 mol% or less. The content of vinyl bonded structural units is more preferably 0 to 30 mol%, even more preferably 0 to 20 mol%, and even more preferably 0 to 10 mol%.

[0044] Furthermore, polymer block (b) may contain structural units derived from other polymerizable monomers other than conjugated diene compounds, as long as they do not interfere with the objectives and effects of the present invention. Examples of such other polymerizable monomers include aromatic vinyl compounds such as styrene, α-methylstyrene, o-methylstyrene, m-methylstyrene, p-methylstyrene, p-t-butylstyrene, 2,4-dimethylstyrene, vinylnaphthalene, and vinylanthracene, as well as at least one compound selected from methyl methacrylate, methyl vinyl ether, N-vinylcarbazole, β-pinene, 8,9-p-menthene, dipentene, methylenenorbornene, and 2-methylenetetrahydrofuran. When polymer block (b) contains structural units derived from monomers of other polymers other than conjugated diene compounds, the bonding configuration is not particularly limited and may be random or tapered.

[0045] The content of structural units derived from polymerizable monomers other than the conjugated diene compound in polymer block (b) is usually preferably 30% by mass or less, and more preferably 10% by mass or less, based on the total mass of polymer block (b).

[0046] From the viewpoint of obtaining the effects of the present invention, the total content of polymer block (a) and polymer block (b) in block polymer (X') is preferably 70% by mass or more, more preferably 80% by mass or more, and even more preferably 90% by mass or more. The upper limit is 100% by mass.

[0047] (Bonding pattern of polymer block (a) and polymer block (b)) Hydrogenated block copolymer (X) is a hydrogenated block copolymer (X') having polymer block (a) and polymer block (b), with at least one end being polymer block (a). When at least one end of block copolymer (X') is composed of polymer block (a), the molded article of the elastomer composition obtained using hydrogenated block copolymer (X), which is a hydrogenated block copolymer (X'), tends to have higher mechanical strength, such as tensile strength. This allows for faithful reproduction of the texture of human skin and internal organs, thereby enhancing the usefulness of anatomical models. From the viewpoint of obtaining the above effect, it is more preferable that all ends of block copolymer (X') are composed of polymer block (a). For example, when block copolymer (X') is a linear block polymer, it is more preferable that both ends are composed of polymer block (a).

[0048] In the block polymer (X'), the bonding configuration is not limited as long as polymer block (a) and polymer block (b) are bonded in the manner described above, and may be linear, branched, radial, or a combination of two or more of these bonding configurations. Among these, the bonding configuration of polymer block (a) and polymer block (b) is preferably linear, and examples of such configurations include a triblock copolymer represented as A-B-A, a tetrablock copolymer represented as A-B-A-B, a pentablock copolymer represented as A-B-A-B-A, and (A-B) when polymer block (a) is represented as A and polymer block (b) as B. ｎ Examples include Z-type copolymers (where Z represents a coupling agent residue and n represents an integer of 3 or more). Among these, triblock copolymers (A-B-A) are preferred due to their ease of manufacture and low hardness.

[0049] In this specification, when identical polymer blocks are linearly linked via a bifunctional coupling agent, the entire linked polymer block is treated as a single polymer block. Accordingly, polymer blocks that should strictly be written as Q-Z-Q (where Z represents a coupling residue), including the above example, are referred to as Q as a whole, unless it is necessary to distinguish them from a single polymer block Q. In this specification, polymer blocks of this type containing coupling agent residues are treated as described above. For example, a block copolymer containing coupling agent residues that should strictly be written as A-B-Z-B-A (where Z represents a coupling residue) is referred to as A-B-A and treated as an example of a triblock copolymer.

[0050] Furthermore, the block copolymer (X') may contain polymer blocks (C) made of other polymerizable monomers other than polymer blocks (a) and polymer block (b), as long as the objectives of the present invention are not impaired. In this case, when polymer block (C) is represented by C, examples of the structure of the block copolymer (X') include A-B-C type triblock copolymer, A-B-C-A type tetrablock copolymer, A-B-A-C type tetrablock copolymer, and the like.

[0051] As described above, the hydrogenated block copolymer (X) is a hydrogenated product of the block copolymer (X'). From the viewpoint of heat resistance and weather resistance, it is preferable that in the hydrogenated block copolymer (X), 80 mol% or more of the carbon-carbon double bonds in the polymer block (b) in the block copolymer (X') are hydrogenated, more preferably 85 mol% or more, and even more preferably 90 mol% or more. The above hydrogenation rate is determined by the content of carbon-carbon double bonds in the structural units derived from the conjugated diene compound in the polymer block (b) before and after hydrogenation. １ These values ​​were calculated using H-NMR spectroscopy.

[0052] The number-average molecular weight of the hydrogenated block copolymer (X) is preferably 20,000 to 600,000, more preferably 35,000 to 400,000, and even more preferably 40,000 to 300,000. If the number-average molecular weight of the hydrogenated block copolymer (X) is 20,000 or more, the heat resistance of the molded article is good, while if it is 500,000 or less, the processability of the elastomer composition is good. In one preferred embodiment of this example, the elastomer composition includes a hydrogenated block copolymer (X) with a number-average molecular weight of less than 150,000. In one more preferred embodiment, the elastomer composition includes two or more hydrogenated block copolymers (X), one or more of which have a number-average molecular weight of less than 150,000. In this way, the processability of the elastomer composition can be further improved by including a hydrogenated block copolymer (X) with a number-average molecular weight of less than 150,000. In a particular embodiment, the elastomer composition comprises at least two hydrogenated block copolymers (X), one of which has a number average molecular weight of less than 150,000 and the other having a number average molecular weight of 150,000 or more.

[0053] The hydrogenated block copolymer (X) preferably has a viscosity of 1,000 mPa·s or less in a 5% by mass toluene solution at 30°C, more preferably in the range of 5 to 800 mPa·s, and even more preferably in the range of 10 to 500 mPa·s. Furthermore, the viscosity of the hydrogenated block copolymer (X) preferably has a viscosity of 50,000 mPa·s or less in a 10% by mass toluene solution at 30°C, more preferably in the range of 20 to 25,000 mPa·s, and even more preferably in the range of 10 to 10,000 mPa·s.

[0054] If the hydrogenated block copolymer (X) has a viscosity of 1,000 mPa·s or less in a 5% by mass toluene solution at 30°C, or a viscosity of 50,000 mPa·s or less in a 10% by mass toluene solution at 30°C, the processability of the elastomer composition is good. In a particular embodiment, the elastomer composition comprises at least two types of hydrogenated block copolymers (X) from the viewpoint of adjusting viscosity, one of which has a viscosity of less than 75 mPa·s in a 10% by mass toluene solution at 30°C, and the other of which has a viscosity of 75 mPa·s or more in a 10% by mass toluene solution at 30°C.

[0055] The hydrogenated block copolymer (X) may have one or more functional groups such as carboxyl groups, hydroxyl groups, acid anhydride groups, amino groups, and epoxy groups in its molecular chain and / or at its molecular terminals, as long as it does not impair the objectives and effects of the present invention.

[0056] The hydrogenated block copolymer (X) may be used alone or in combination of two or more types. Using two or more hydrogenated block copolymers (X) in combination is preferable because it allows for adjustment of the viscosity of the molten or molten kneaded elastomer composition, thereby improving processability and other properties.

[0057] Furthermore, commercially available block copolymers can be used as the hydrogenated block copolymer (X). For example, "Septon 1001", "Septon 1020", "Septon 2002", "Septon 2004", "Septon 2005", "Septon 2006", "Septon 2063", "Septon 2104", "Septon 4033", "Septon 4055", "Septon 4077", "Septon 4099", "Septon HG252", "Septon 8004", "Septon 8006", "Septon 8007", and "Septon 8076" (all product names) manufactured by Kuraray Co., Ltd. are preferred.

[0058] (Method for producing hydrogenated block copolymer (X)) The block copolymer (X') before hydrogenation of hydrogenated block copolymer (X) can be produced by solution polymerization, emulsion polymerization, or solid-phase polymerization, etc. Among these, solution polymerization is preferred, and known methods such as ionic polymerization such as anionic polymerization and cationic polymerization, and radical polymerization can be applied. Among these, anionic polymerization is preferred. In the production of hydrogenated block copolymer (X) using anionic polymerization, for example, an aromatic vinyl compound and a conjugated diene compound are sequentially added in the presence of a solvent, an anionic polymerization initiator, and optionally a Lewis base to obtain block copolymer (X'), and then hydrogenated block copolymer (X) can be obtained by hydrogenating block copolymer (X) (X).

[0059] Examples of organolithium compounds used as polymerization initiators in the above method include monolithium compounds such as methyllithium, ethyllithium, pentyllithium, n-butyllithium, sec-butyllithium, and tert-butyllithium, and dilithium compounds such as tetraethylenedilithium.

[0060] The solvent is not particularly limited as long as it does not adversely affect the anionic polymerization reaction. Examples include aliphatic hydrocarbons such as cyclohexane, methylcyclohexane, n-hexane, and n-pentane; and aromatic hydrocarbons such as benzene, toluene, and xylene. The polymerization reaction is usually carried out at 0 to 100°C for 0.5 to 50 hours.

[0061] Lewis bases play a role in controlling the microstructure of structural units derived from conjugated diene compounds. Examples of such Lewis bases include dimethyl ether, diethyl ether, tetrahydrofuran, dioxane, ethylene glycol dimethyl ether, pyridine, N,N,N',N'-tetramethylethylenediamine, trimethylamine, and N-methylmorpholine. Lewis bases may be used individually or in combination of two or more.

[0062] After polymerization is carried out by the method described above, the polymerization reaction can be stopped by adding active hydrogen compounds such as alcohols, carboxylic acids, and water, and then hydrogenated in an inert organic solvent in the presence of a hydrogenation catalyst according to a known method to obtain a hydrogenated block copolymer (X). As described above, in the present invention, a hydrogenated block copolymer (X) in which 80 mol% or more of the carbon-carbon double bonds of the polymer block (b) in the block copolymer (X') are hydrogenated is preferred, a hydrogenated block copolymer (X) in which 85 mol% or more of the carbon-carbon double bonds of the polymer block (b) in the block copolymer (X') are hydrogenated is more preferred, and a hydrogenated block copolymer (X) in which 90 mol% or more of the carbon-carbon double bonds of the polymer block (b) in the block copolymer (X') are hydrogenated is even more preferred.

[0063] Hydrogenation reactions can be carried out in the presence of a hydrogenation catalyst under conditions of a reaction temperature of 20 to 100°C and a hydrogen pressure of 0.1 to 10 MPa.

[0064] Examples of hydrogenation catalysts include Raney nickel; heterogeneous catalysts in which metals such as platinum (Pt), palladium (Pd), ruthenium (Ru), rhodium (Rh), and nickel (Ni) are supported on a carrier such as carbon, alumina, or diatomaceous earth; Ziegler-type catalysts consisting of combinations of organometallic compounds made of Group 8 metals such as nickel and cobalt with organoaluminum compounds such as triethylaluminum and triisobutylaluminum, or organolithium compounds; metallocene-type catalysts consisting of bis(cyclopentadienyl) compounds of transition metals such as titanium, zirconium, and hafnium; and organometallic compounds such as lithium, sodium, potassium, aluminum, zinc, or magnesium. The above-mentioned hydrogenation catalysts may be used in combination.

[0065] The hydrogenated block copolymer (X) obtained in this manner can be obtained by pouring the polymerization reaction solution into methanol or the like to solidify it, then heating or drying under reduced pressure, or by pouring the polymerization reaction solution into boiling water and removing the solvent by azeotropic removal (so-called steam stripping), and then heating or drying under reduced pressure.

[0066] The amount of hydrogenated block copolymer (X) in the aromatic vinyl compound elastomer (A) is preferably 50% by mass or more, more preferably 80% by mass or more, even more preferably 90% by mass or more, and may be 100% by mass.

[0067] The number average molecular weight of the aromatic vinyl compound elastomer (A) is preferably 20,000 to 600,000, more preferably 35,000 to 400,000, and even more preferably 40,000 to 300,000. If the number average molecular weight of the aromatic vinyl compound elastomer (A) is 20,000 or more, the heat resistance of the molded article is good, while if it is 500,000 or less, the processability of the elastomer composition is good. In one preferred embodiment of this example, the elastomer composition includes an aromatic vinyl compound elastomer (A) with a number average molecular weight of less than 150,000. In one more preferred embodiment, the elastomer composition includes two or more aromatic vinyl compound elastomers (A), one or more of which have a number average molecular weight of less than 150,000. By including an aromatic vinyl compound elastomer (A) with a number average molecular weight of less than 150,000 in this way, the processability of the elastomer composition can be further improved.

[0068] The aromatic vinyl compound elastomer (A) preferably has a viscosity of 1,000 mPa·s or less in a 5% by mass toluene solution at 30°C, more preferably in the range of 5 to 800 mPa·s, and even more preferably in the range of 10 to 500 mPa·s. Furthermore, the viscosity of the aromatic vinyl compound elastomer (A) preferably has a viscosity of 50,000 mPa·s or less in a 10% by mass toluene solution at 30°C, more preferably in the range of 20 to 25,000 mPa·s, and even more preferably in the range of 10 to 10,000 mPa·s.

[0069] Aromatic vinyl compound-based elastomer (A) exhibits good processability if its viscosity in a 5% by mass toluene solution at 30°C is 1,000 mPa·s or less, or if its viscosity in a 10% by mass toluene solution at 30°C is 50,000 mPa·s or less.

[0070] In the elastomer composition of this embodiment, the content of aromatic vinyl compound elastomer (A) is preferably 1 to 25% by mass, more preferably 3 to 20% by mass, even more preferably 5 to 18% by mass, and even more preferably 7 to 16% by mass, from the viewpoint of ensuring oil retention. It is also preferable that the content of aromatic vinyl compound elastomer (A) in the molded article of the elastomer composition is within the above range.

[0071] (Method for producing aromatic vinyl compound elastomer (A)) The method for producing aromatic vinyl compound elastomer (A) is the same as the method for producing the block copolymer (X') before hydrogenation of the hydrogenated block copolymer (X) described above. When aromatic vinyl compound elastomer (A) is a hydrogenated product, the hydrogenation reaction can be carried out in the same manner as the hydrogenation reaction of the hydrogenated block copolymer (X) described above.

[0072] <Oil (Y)> The elastomer composition of this embodiment has a kinematic viscosity of 50 mm at 40°C. ２ It contains oil (Y) with a concentration of less than / s (hereinafter also simply referred to as "oil (Y)"). Oil (Y) usually functions as a plasticizer in the elastomer composition of this embodiment. In this specification, oil refers to a nonpolar solvent. Furthermore, oil (Y) is preferably a nonpolar aprotic solvent.

[0073] The kinematic viscosity of oil (Y) at 40°C is 50 mm². ２ Because the kinematic viscosity is less than / s, the elastomer composition obtained by incorporating it has excellent processability for forming molded articles. The oil (Y) contained in the elastomer composition of this embodiment may be one type or multiple types. When there are multiple types of oil (Y), it is preferable that the mixture of the multiple types of oils is within the kinematic viscosity range described above and below.

[0074] From the viewpoint of obtaining the above effects, the kinematic viscosity of oil (Y) at 40°C is preferably 40 mmHg. ２ / s or less, more preferably 30 mm ２ / s or less, more preferably 30 mm ２ Less than / s, more preferably 25 mm ２ / s or less, more preferably 20 mm２ It is less than or equal to / s. There is no particular lower limit to the kinematic viscosity of oil (Y) at 40°C, but for example, 0.1 mm ２ / s or more, 1mm ２ / s or more, 3mm ２ / s or more, 5mm ２ / s or more, 7mm ２ / s or more, or 9 mm ２ It may be set to 1 / s or more. That is, the kinematic viscosity of oil (Y) at 40°C is preferably 1 to 40 mm². ２ / s, more preferably 3 to 30 mm ２ / s, more preferably 3 mm ２ / s or more 30mm ２ Less than / s, more preferably 5 to 25 mm ２ / s, more preferably 7 to 20 mm ２ It is / s.

[0075] The kinematic viscosity of oil at 40°C can be measured using a method compliant with ASTM D445-21.

[0076] Examples of oil (Y) include mineral oils such as paraffinic process oils and naphthenic process oils; vegetable oils such as peanut oil and rosin; aromatic oils; phosphate esters; low molecular weight polyethylene glycol; liquid paraffin; synthetic oils such as low molecular weight ethylene, ethylene-α-olefin copolymer oligomers, liquid polybutene, liquid polyisoprene or its hydrogenated products, liquid polybutadiene or its hydrogenated products; and so on. Among these, at least one selected from the group consisting of paraffinic process oils and naphthenic process oils is preferred in terms of compatibility with aromatic vinyl compound elastomer (A), and paraffinic process oil is more preferred. These may be used individually or in combination of two or more.

[0077] The amount of oil (Y) in the elastomer composition of this embodiment is in the range of 500 to 4000 parts by mass per 100 parts by mass of aromatic vinyl compound elastomer (A). When the amount of oil (Y) per 100 parts by mass of aromatic vinyl compound elastomer (A) is 500 parts by mass or more, preferably 550 parts by mass or more, and more preferably 600 parts by mass or more, a molded article with low hardness can be obtained. Furthermore, when the amount of oil (Y) per 100 parts by mass of aromatic vinyl compound elastomer (A) is 4000 parts by mass or less, preferably 3000 parts by mass or less, more preferably 2500 parts by mass or less, and even more preferably 2000 parts by mass or less, a molded article with excellent bleed-out resistance can be obtained. That is, the amount of oil (Y) per 100 parts by mass of aromatic vinyl compound elastomer (A) is preferably 550 to 3000 parts by mass, more preferably 600 to 2500 parts by mass, and even more preferably 600 to 2000 parts by mass.

[0078] In the elastomer composition of this embodiment, the oil (Y) content is preferably 70 to 98% by mass, more preferably 75 to 95% by mass, and even more preferably 80 to 93% by mass, from the viewpoint of achieving low hardness of the molded article. It is also preferable that the oil (Y) content in the molded article of the elastomer composition be within the above range.

[0079] Furthermore, the total content of aromatic vinyl compound elastomer (A) and oil (Y) in the elastomer composition of this embodiment is preferably 60% by mass or more, more preferably 70% by mass or more, even more preferably 80% by mass or more, and even more preferably 85% by mass or more. When the total content is 60% by mass or more, the effects of the present invention can be effectively expressed, the processability to molded articles is good, and the molded article manufacturability is superior due to excellent bleed-out resistance. The upper limit of the total content is 100% by mass.

[0080] <Organic Additive (Z)> The elastomer composition of this embodiment contains an organic additive (Z). In this embodiment, the organic additive (Z) is an organic additive (Z) that is soluble in the oil (Y), i.e., the oil (Y) contained in the elastomer composition of this embodiment, at 160°C. Since the elastomer composition contains the organic additive (Z), the bleed-out of the oil (Y) when it is formed into a molded body can be suppressed. One type of organic additive (Z) may be used alone, or two or more types may be used in combination.

[0081] The organic additive (Z) is not limited as long as it produces the above-mentioned effects. Whether or not the above-mentioned effects are produced can be confirmed by preparing an elastomer composition containing the organic compound suspected to be the organic additive (Z) and forming it into a molded article. In other words, the organic additive (Z) can also be identified from the molded article.

[0082] The organic additive (Z) is preferably an organic compound that is solid at room temperature, for example, 25°C. From the viewpoint of suppressing unintended excessive aggregation, it is preferable that the organic additive (Z) is not an organic compound disposed on the surface of the inorganic compound particles. That is, it is preferable that the organic additive (Z) exists on its own in the elastomer composition, rather than being part of the inorganic-organic composite material. On the other hand, from the viewpoint of increasing the possibility of contact with the oil (Y), the organic additive (Z) may be an organic compound disposed on the surface of the inorganic compound particles.

[0083] The amount of solubility at 160°C, as described above, may be determined using the aforementioned specific solvent (white mineral oil) instead of oil (Y). The preferred range for each solubility is the same as the range described above.

[0084] The organic additive (Z) is preferably an organic compound having a molecular weight of preferably 670 or more, more preferably 750 or more, even more preferably 900 or more, preferably 1500 or less, more preferably 1300 or less, and even more preferably 1200 or less. That is, the molecular weight of the organic additive (Z) is preferably 670 to 1500, more preferably 750 to 1300, and even more preferably 900 to 1200. Although the reason is not clear, it is presumed that having a molecular weight of the organic additive (Z) within the above range allows it to be compatible with oil (Y), etc., in the molten elastomer composition, and that subsequent cooling makes it easier to precipitate in the molded body, thereby contributing to the appropriate dispersion of the organic additive (Z) in the molded body. From the viewpoint of controlling the amount of precipitation in the molded body, it is more preferable that the organic additive (Z) is an organic compound having a melting point of preferably 56°C or more, more preferably 70°C or more, even more preferably 80°C or more, preferably 150°C or less, more preferably 140°C or less, and even more preferably 130°C or less. In other words, the melting point of the organic additive (Z) is preferably 56 to 150°C, more preferably 70 to 140°C, and even more preferably 80 to 130°C. The melting point may be considered as an indicator instead of the freezing point. The melting point or freezing point may be a literature value or a catalog value.

[0085] The organic additive (Z) is preferably a polar group-containing organic compound. The polar group is preferably a functional group containing one or more atoms selected from the group consisting of nitrogen, oxygen, phosphorus, and sulfur atoms, more preferably a functional group containing one or more atoms selected from the group consisting of oxygen and phosphorus atoms, and even more preferably a functional group containing an oxygen atom. Although the reason is not clear, it is presumed that the fact that the organic additive (Z) is a polar group-containing organic compound allows for adequate compatibility with oil (Y), etc., in the molten elastomer composition, and as a result contributes to the dispersion of the organic additive (Z) in the molded body. The number of polar groups contained in the polar group-containing organic compound is not limited as long as it does not excessively impair the above-mentioned effects. From the viewpoint of adequately ensuring compatibility with oil (Y), etc., the polar group-containing organic compound preferably has two or more, more preferably three or more, and even more preferably four or more polar groups per molecule. In one embodiment, the organic additive (Z) contains an organic compound having at least four polar groups per molecule. The upper limit on the number of polar groups contained in a polar group-containing organic compound may be, for example, 12 or fewer, or 10 or fewer.

[0086] In a particular embodiment, the organic additive (Z) comprises a polar group-containing organic compound that satisfies at least one, preferably both, of the above-mentioned molecular weight range and / or melting point or freezing point range. A typical example of such an organic compound is pentaerythritol tetrakis(3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate).

[0087] The polar group-containing organic compound is preferably at least one selected from phenolic hydroxyl group-containing organic compounds and their radical reaction products. Because the polar group is a phenolic hydroxyl group, the phenolic hydroxyl group-containing organic compound can also function as an antioxidant. The function of the phenolic hydroxyl group-containing organic compound as an antioxidant can suppress deterioration due to oxidation of components during melt-mixing of the elastomer composition and in the molded article, as well as the off-odor of the oil (Y). Since antioxidants usually exert their function through radical reactions, if the organic additive (Z) contains a phenolic hydroxyl group-containing organic compound, the elastomer composition and its molded article may contain radical reaction products of the phenolic hydroxyl group-containing organic compound. Radical reaction products can be identified by confirming oxygen atoms or groups of oxygen atoms derived from the phenolic hydroxyl group using NMR.

[0088] From the viewpoint of enhancing the function as an antioxidant, it is preferable that the phenolic hydroxyl group-containing organic compound is a hindered phenol compound. A hindered phenol compound is typically a compound having a tert-butyl group at at least one of the two ortho-positions relative to the hydroxyl group of a hydroxyphenyl group, and preferably a compound having tert-butyl groups at two ortho-positions relative to the hydroxyl group of a hydroxyphenyl group.

[0089] The number of phenolic hydroxyl groups in a phenolic hydroxyl group-containing organic compound is not limited as long as it does not excessively impair the effects of the polar groups described above. From the viewpoint of enhancing its function as an antioxidant, the phenolic hydroxyl group-containing organic compound preferably has two or more, more preferably three or more, phenolic hydroxyl groups per molecule. In one embodiment, the organic additive (Z) contains a phenolic hydroxyl group-containing organic compound having at least three phenolic hydroxyl groups per molecule. The upper limit of the number of phenolic hydroxyl groups in the phenolic hydroxyl group-containing organic compound may be, for example, five or fewer, or four or fewer.

[0090] Since the organic additive (Z) also functions as an antioxidant, it is possible to suppress the amount of additives that need to be incorporated into the elastomer composition. From this viewpoint, in one preferred embodiment, the organic additive (Z) comprises at least one selected from pentaerythritol tetrakis(3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate and its radical reaction products, more preferably the organic additive (Z) comprises at least one selected from pentaerythritol tetrakis(3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate and its radical reaction products, and even more preferably the organic additive (Z) comprises at least pentaerythritol tetrakis(3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate.

[0091] As described above, the content of the organic additive (Z) in the elastomer composition of this embodiment is 0.5% by mass or more. From the viewpoint of improving bleed-out resistance, the content of the organic additive (Z) in the elastomer composition is preferably 0.6% by mass or more, more preferably 0.7% by mass or more, even more preferably 0.8% by mass or more, and even more preferably 0.9% by mass or more, and may be 1.0% by mass or more, 1.1% by mass or more, 1.2% by mass or more, 1.3% by mass or more, 1.4% by mass or more, 1.5% by mass or more, or 1.6% by mass or more. From the viewpoint of improving the usefulness of the anatomical model, the content of the organic additive (Z) in the elastomer composition is preferably 3.7% by mass or less, more preferably 3.3% by mass or less, even more preferably 3.0% by mass or less, and even more preferably 2.7% by mass or less. In other words, the content of the organic additive (Z) in the elastomer composition is preferably 0.6 to 3.7% by mass, more preferably 0.7 to 3.3% by mass or less, even more preferably 0.8 to 3.0% by mass, and even more preferably 0.9 to 2.7% by mass or less. It is also preferable that the content of the organic additive (Z) in the molded article of the elastomer composition is within the above range.

[0092] In the elastomer composition of this embodiment, the amount of organic additive (Z) per 1 part by mass of oil (Y) is preferably 0.008 parts by mass or more, more preferably 0.009 parts by mass or more, and even more preferably 0.010 parts by mass or more, and may be 0.011 parts by mass or more, 0.013 parts by mass or more, 0.015 parts by mass or more, 0.017 parts by mass or more, 0.019 parts by mass or more, 0.021 parts by mass or more, or 0.023 parts by mass or more, from the viewpoint of improving bleed-out resistance. From the viewpoint of improving the usefulness of the anatomical model, the amount of organic additive (Z) per 1 part by mass of oil (Y) is preferably 0.040 parts by mass or less, more preferably 0.037 parts by mass or less, even more preferably 0.034 parts by mass or less, and even more preferably 0.031 parts by mass or less. In other words, the amount of organic additive (Z) per 1 part by mass of oil (Y) is preferably 0.008 to 0.040 parts by mass, more preferably 0.009 to 0.037 parts by mass, even more preferably 0.010 to 0.034 parts by mass, and even more preferably 0.010 to 0.031 parts by mass. In the molded body of the elastomer composition, it is preferable that the amount of organic additive (Z) per 1 part by mass of oil (Y) is within the above range, but a slight upward deviation from the above range is permissible due to the bleeding out of oil (Y) over time.

[0093] <Pigment (B)> The elastomer composition of this embodiment may or may not contain pigment (B). Either an organic pigment or an inorganic pigment can be used as the pigment. By including pigment (B) in the elastomer composition, it becomes possible to impart color and opacity to the molded article according to the pigment (B). From the viewpoint of maintaining low hardness of the molded article, it is preferable that pigment (B) includes an organic pigment. From the viewpoint of imparting opacity to the molded article, it is preferable that pigment (B) includes an inorganic pigment.

[0094] Examples of organic pigments include red organic pigments, yellow organic pigments, blue organic pigments, and orange organic pigments. Examples of these organic pigments include phthalocyanine pigments, anthraquinone pigments, quinacridone pigments, dioxazine pigments, isoindolinone pigments, isoindoline pigments, indigo pigments, quinophthalone pigments, diketopyrrolopyrrole pigments, perylene pigments, perinone pigments, benzimidazolon pigments, and azo pigments. From the viewpoint of coloring the molded body to resemble human skin and improving its usefulness as a human body model, it is preferable to use at least one selected from the group consisting of red organic pigments, yellow organic pigments, and orange organic pigments as pigment (B), and it is more preferable to use at least one selected from the group consisting of red organic pigments and yellow organic pigments. In one embodiment, from the viewpoint of coloring the molded body to resemble human skin, pigment (B) includes both red organic pigments and yellow organic pigments. From the viewpoint of enhancing the usefulness of the anatomical model by coloring the molded body to resemble the internal organs of the human body, it is preferable to use at least one selected from the group consisting of red organic pigment, yellow organic pigment, and orange organic pigment as the pigment (B).

[0095] Inorganic pigments include black inorganic pigments such as carbon black, lamp black, acetylene black, bone black, thermal black, channel black, furnace black, and titanium black, as well as titanium dioxide (TiO, Ti ２ O ３ , TiO ２ ), zinc oxide (Pb ３ O ４ ), iron oxide (Fe ２ O ３Examples of composite metal oxides include metal oxides such as antimony oxide and zirconium oxide (zircon oxide), metal sulfides such as zinc sulfide, ultramarine (Pigment Blue 29), zinc phosphate, barium sulfate, manganese phosphate, cobalt aluminate, cobalt stanate, cobalt zincate, antimony oxide, antimony sulfide, cerium sulfide, lanthanum sulfide, chromium oxide, zinc chromate, nickel-based, bismuth-based, vanadium-based, molybdenum-based, cadmium-based, titanium-based, zinc-based, manganese-based, cobalt-based, iron-based, chromium-based, antimony-based, magnesium-based, and aluminum-based oxides. In one embodiment, from the viewpoint of imparting opacity to the molded body, pigment (B) includes titanium oxide. In a particular embodiment, from the viewpoint of providing sufficient opacity while coloring the molded body to resemble human skin, pigment (B) includes both a red organic pigment and a yellow organic pigment, and an inorganic pigment, preferably titanium oxide, for example, titanium dioxide (TiO2). ２ ) and includes.

[0096] The content of pigment (B) in the elastomer composition is not limited as long as it does not excessively inhibit the intended effects of the present invention, but for example it may be 10% by mass or less, 5% by mass or less, or 3% by mass or less, for example 0.01% by mass or more, 0.05% by mass or more, or 0.1% by mass or more. It is also preferable that the content of pigment (B) in the molded article of the elastomer composition is within the above range.

[0097] <Component (C): Other Components> The elastomer composition of this embodiment may or may not contain components (C) other than aromatic vinyl compound elastomer (A), oil (Y), organic additive (Z), and pigment (B). For example, the elastomer composition of this embodiment may contain, to the extent that the effects of the present invention are not impaired, at least one selected from the group consisting of components (C) such as ultraviolet absorbers, light stabilizers, anti-aging agents, antioxidants, dyes, fillers, nucleating agents, flame retardants, and dispersants; hydrogenated resins such as hydrogenated coumarone-indene resin, hydrogenated rosin resin, hydrogenated terpene resin, and alicyclic hydrogenated petroleum resin; tackifying resins such as aliphatic resins made of olefins and diolefin polymers; other polymers such as hydrogenated polyisoprene, hydrogenated polybutadiene, hydrogenated styrene-butadiene random copolymer, hydrogenated styrene-isoprene random copolymer, butyl rubber, polyisobutylene, and polybutene; and liquid components other than oil (Y) such as dispersion media and polar solvents. Furthermore, if the aforementioned component (C) also functions as an organic additive (Z), then such component is classified as an organic additive (Z).

[0098] Among the above, the elastomer composition of this embodiment preferably contains, as component (C), at least one additive selected from the group consisting of ultraviolet absorbers, light stabilizers, antioxidants, colorants, dispersants, and fillers. Furthermore, from the viewpoint of use in anatomical models, the elastomer composition of this embodiment preferably contains at least an ultraviolet absorber, an antioxidant, and a colorant.

[0099] The dye is preferably used in place of or in addition to pigment (B) in some cases.

[0100] The dye content in the elastomer composition is usually in the range of 0.01 to 10% by mass, preferably 0.1 to 5% by mass, and one type can be used alone or in combination of two or more types. It is also preferable that the dye content in the molded body of the elastomer composition be within the above range.

[0101] The fillers are not particularly limited, but examples include reinforcing fillers such as wood flour, pulp, cotton chips, asbestos, glass fiber, carbon fiber, mica, walnut shell powder, rice husk powder, graphite, diatomaceous earth, white clay, silica (fumed silica, settling silica, crystalline silica, fused silica, dolomite, anhydrous silicic acid, hydrated silicic acid, etc.), and carbon black; fillers such as calcium carbonate, magnesium carbonate, diatomaceous earth, calcined clay, clay, talc, titanium dioxide, bentonite, organic bentonite, ferric oxide, red iron oxide, aluminum powder, flint powder, zinc oxide, activated zinc oxide, zinc powder, zinc carbonate, and shirasu balloons; and fibrous fillers such as asbestos, glass fiber and glass filament, carbon fiber, Kevlar® fiber, and polyethylene fiber. Among the above, calcium carbonate is preferred.

[0102] These may be used individually or in combination of two or more types.

[0103] The filler content in the elastomer composition is typically in the range of 0.1 to 15% by mass, preferably 0.5 to 10% by mass. It is also preferable that the filler content in the molded body of the elastomer composition be within the above range.

[0104] Examples of flame retardants include magnesium hydroxide and aluminum hydroxide. The flame retardant may also serve as the filler mentioned above.

[0105] When a flame retardant is used, its content is usually in the range of 0.1 to 15% by mass, preferably 0.5 to 10% by mass, in the elastomer composition. From the viewpoint of obtaining a molded article with low hardness, it is preferable that the elastomer composition does not contain a flame retardant (i.e., the flame retardant content is 0% by mass). In a specific embodiment of this embodiment, the magnesium hydroxide content in the elastomer composition is 1.0% by mass or less, preferably 0.5% by mass or less, and more preferably magnesium hydroxide-free. Also, in a specific embodiment of this embodiment, the aluminum hydroxide content in the elastomer composition is 1.0% by mass or less, preferably 0.5% by mass or less, and more preferably aluminum hydroxide-free. Magnesium hydroxide and aluminum hydroxide are usually inorganic compound particles. This makes it possible to suppress problems caused by using inorganic compound particles (for example, deterioration of processability of the molded article, deterioration of the feel of the molded article, hardening of the molded article). It is also preferable that the flame retardant content in the molded article of the elastomer composition is within the above range.

[0106] As mentioned above, liquid components include dispersion media other than oil or polar solvents. The dispersion media is preferably a compound that can volatilize before processing into a molded article. The content of the dispersion media in the elastomer composition is preferably 5% by mass or less, more preferably 3% by mass or less, even more preferably 1% by mass or less, and even more preferably 0% by mass (i.e., not included). The content of the dispersion media in the molded article of the elastomer composition is also preferably within the above range. The content of the polar solvent in the elastomer composition is preferably 5% by mass or less, more preferably 3% by mass or less, even more preferably 1% by mass or less, and even more preferably 0% by mass (i.e., not included) from the viewpoint of promoting the precipitation of the organic additive (Y). The content of the polar solvent in the molded article of the elastomer composition is also preferably within the above range. The total content of liquid components, for example, the dispersion media and polar solvent, is preferably 6% by mass or less, more preferably 4% by mass or less, even more preferably 2% by mass or less, and even more preferably 0% by mass (i.e., not included) in the elastomer composition. It is preferable that the liquid component content in the molded elastomer composition is also within the above range.

[0107] (Specific Gravity) The specific gravity of the elastomer composition of this embodiment at 25°C is preferably in the range of 0.80 to 1.05, more preferably 0.82 to 1.00, and even more preferably 0.84 to 0.95, from the viewpoint of obtaining a human body model with a weight similar to that of the human body. The specific gravity of the elastomer composition can be measured by a method in accordance with JIS Z8807:2012 8 Method for measuring density and specific gravity by liquid weighing method.

[0108] <Method for Manufacturing Elastomer Composition and Molded Article Thereof> The method for manufacturing the elastomer composition of this embodiment is not particularly limited. For example, the elastomer composition of this embodiment can be manufactured by melt-kneading the above-mentioned aromatic vinyl compound elastomer (A), oil (Y), organic additive (Z), and optionally pigment (B) and component (C) using a mixing device such as a mixing roll, kneader, Banbury mixer, Bravender mixer, or single-screw or twin-screw extruder, or by melting it using a melting device such as a melter, or by melting a molten compound (sometimes also called a "compound") obtained by melt-kneading using a mixing device such as a mixing roll, kneader, Banbury mixer, Bravender mixer, or single-screw or twin-screw extruder, using a melting device such as a melter. Melt-kneading and melting are generally carried out at 100 to 250°C. Vacuum degassing is preferably performed during or after manufacturing.

[0109] After the above melting or melt-kneading is performed, a molded body formed from the elastomer composition of this embodiment can be manufactured by molding using a known method, for example, by pouring it into a metal mold or by pouring it into a resin mold. There are no particular restrictions on the molding method, and it can be appropriately selected depending on the size, shape, etc., of the molded body to be manufactured. For example, molding methods such as injection molding, compression molding, casting, extrusion molding, cast molding, and press molding can be used.

[0110] <Applications> The elastomer composition and molded body of this embodiment are suitable for the anatomical models described later, but their elastomer properties and durability allow them to be used for other applications as well. For example, they can be effectively used in a wide range of fields, such as cushioning materials, vibration damping materials, sealing materials, heat dissipation materials, sealing materials, expansion materials, heat insulating materials, soundproofing materials, sound-insulating materials, light guiding materials, packaging materials, shoes, jackets, protectors, helmets, prosthetics, artificial legs, mats, pads, beds, mattresses, pillows, wheelchairs, child seats, strollers, mobile phones, digital cameras, personal computers, game consoles, navigation systems, home appliances, power tools, industrial equipment, robots, automobiles, ships, aircraft, motors, generators, solar cells, fiber optic cables, fiber optic connectors, furniture, stationery, toys, shoe insoles, window frames, candles, food models, etc.

[0111] [Human Body Model] The elastomer composition and molded body thereof of this embodiment are also useful as human body models. The elastomer composition and molded body thereof have a specific gravity close to that of the human body, a texture similar to human skin and internal organs, and tend to have high durability, making them suitable for use as human body models. When the elastomer composition and molded body thereof of this embodiment are used as human body models, the content of the organic additive (Z) in the elastomer composition is preferably less than 3.7% by mass, more preferably 3.3% by mass or less, even more preferably 3.0% by mass or less, and even more preferably 2.7% by mass or less.

[0112] The human body model described above may consist solely of a molded body of the elastomer composition of this embodiment, or it may be a human body model in which a part is composed of the elastomer composition of this embodiment. Furthermore, in this specification, the human body model is not limited to a model of the entire human body, but also includes models of a part of the human body.

[0113] In particular, since the molded body of this embodiment has a texture similar to human skin and internal organs, when used as a human body model, it is preferable that the human body model includes at least one part selected from the group consisting of skin, fat, organs, muscles, and blood vessels, which is made of the molded body of the elastomer composition described above.

[0114] There are no particular restrictions on the method of manufacturing a human body model; for example, it can be manufactured by molding the compound resin produced by the method described above using a mold having a desired shape.

[0115] As described above, anatomical models tend to have a texture and weight that more closely resembles that of a human body, and also possess high durability, making them suitable as anatomical models for medical phantom or medical simulator applications.

[0116] The present invention will be described in detail below with reference to examples, but the present invention is not limited to these examples. The physical properties in the examples and comparative examples were measured or evaluated by the following methods.

[0117] <1. (A) Components: Hydrogenation rate, content of styrene-derived structural units> １ The results were obtained by 1H-NMR measurement. • Equipment: Nuclear magnetic resonance spectrometer "Lambda-500" (manufactured by JEOL Ltd.) • Solvent: Deuterated chloroform

[0118] <2. Characteristics of Component (Y) and Component (Y')> The characteristics of the oils that are Component (Y) and Component (Y') were identified as follows.

[0119] <2-1. Oil Viscosity (40°C)> The kinematic viscosity (mm²) of the oil at 40°C was determined according to the method compliant with ASTM D445-24. ２ The time ( / s) was measured.

[0120] <2-2. Specific Gravity of Oil (25°C)> The specific gravity of the oil at 25°C was measured according to the method compliant with ASTM D4052-22.

[0121] <3. Characteristics of Component (Z) and Component (Z')> The characteristics of the organic additives, which are Component (Z) and Component (Z'), were identified as follows.

[0122] <3-1. Solubility in the oil used (160°C)> At an ambient temperature of 25°C, 100g of oil to be used in a stainless steel container was weighed out, and 2.4g of organic additive was added. The stainless steel container was heated on a hot plate for 30 minutes while stirring with a stirring rod until the internal temperature reached 160°C. When the internal temperature reached 160°C, the state of the organic additive was visually checked. If no solid matter was observed and the organic additive was completely dissolved, the mass S of the first solid matter was... １６０ It was assumed that this was zero. If there was solid matter, but the amount of organic additive was less than when the organic additive was added at an ambient temperature of 25°C, it was assumed that the organic additive was dissolved in the oil at 160°C so as to contain the first solid matter. In this case, the mass S of the first solid matter was... １６０ We assumed that this value is greater than zero.

[0123] <3-3. Requirements for Organic Additives: Precipitation Test with Specific Oil (Cooling from 160°C to 50°C)> The oil described below (Y1) was prepared as the specific oil. At an ambient temperature of 25°C, 100g of the specific oil was weighed into the first and second stainless steel containers, and 2.4g of the organic additive was added. The stainless steel containers were heated on a hot plate for 30 minutes while stirring with a stirring rod until the internal temperature reached 160°C. Stirring was stopped when the internal temperature reached 160°C, and the contents were visually inspected. The first stainless steel container was held on the hot plate to maintain an internal temperature of 160°C. The second stainless steel container was removed from the hot plate and placed on a wooden stand, and allowed to cool naturally at an ambient temperature of 25°C. The internal temperature was measured every 5 minutes, and the contents were visually inspected. The contents were visually inspected when the internal temperature reached 50°C ± 5°C. It was found that it takes 30 minutes for the specific oil to reach 50°C ± 5°C. If no solids are observed at 160°C and the organic additive is completely dissolved, the mass S of the first solid is... １６０Assuming that is zero, if solid matter is observed at 50°C ± 5°C, the actual precipitate amount P is considered to be greater than 0, and if no solid matter is observed, the actual precipitate amount P is considered to be 0. The first solid matter in a specific oil maintained at 160°C and the second solid matter in a specific oil at 50°C ± 5°C are visually or optically compared, and if it can be determined that the second solid matter is greater than the first solid matter, the actual precipitate amount P is considered to be greater than 0, and if it cannot be determined whether the second solid matter is greater than the first solid matter, the solid matter is filtered out at 160°C and 50°C respectively, and the weight of the solid matter is measured to obtain S １６０ S ５０ Substituting into the following equation, we found P: P = S ５０ -S １６０

[0124] <4. Specific Gravity of Elastomer Compositions> The specific gravity of the molten mixture of elastomer compositions obtained in each example and comparative example was measured at 25°C using a method compliant with JIS Z8807:2012 8 Method for Measuring Density and Specific Gravity by Weighing in Liquid. The obtained molten mixture of elastomer compositions was cut into pieces of approximately 9 g each, and the specific gravity was measured using a hydrometer (Shinko Denshi Co., Ltd. DME-220H). Measurements were taken with n=3, and the average value was taken as the specific gravity of the elastomer composition.

[0125] <5. Manufacturability of Molded Articles> <5-1. Processability> For molded articles formed from the elastomer compositions obtained in each example and comparative example, the appearance of the mold contact surface was observed visually 240 minutes after molding, and the elasticity was observed by oscillation when the non-mold contact surface was used as the support surface. The observation results were classified according to the following criteria: A: The article had sufficient integrity and elasticity to withstand practical use. B: The article had sufficient integrity to withstand practical use, but the elasticity was insufficient. C: The article had no integrity, or had some degree of integrity, but it was not sufficient integrity to withstand practical use.

[0126] <5-2. Bleed-out Resistance> The bleed-out resistance of molded bodies formed from the elastomer compositions obtained in each example and comparative example was evaluated as follows. First, the molded body immediately after molding was placed on one side of commercially available copy paper (plain paper without surface treatment) with the side that had been in contact with the bottom surface of the mold in contact with it, and stored for 30 minutes under normal pressure, a temperature of 25°C, and a humidity of 60% RH. Next, the molded body was peeled off the copy paper. After that, the surface on the copy paper where the molded body was placed was visually observed. When oil marks were observed on the surface where the molded body was placed, the oil marks along the outline of the molded body were usually more prominent than the oil marks inside the outline, because oil that bled out from the outer surface of the non-placed surface of the molded body accumulated around the outline.

[0127] The observation results were classified according to the following criteria: A: No significant oil marks were observed along the outline or inside the outline of the molded body. B: Significant oil marks were observed along the outline of the molded body, and some oil marks were observed inside the outline. C: Significant oil marks were observed along both the outline and inside the outline of the molded body.

[0128] <5-3. Evaluation of Manufacturability of Molded Products> The evaluation results from 5-1 and 5-2 above were classified according to the following criteria: A: Both processability and bleed-out resistance were evaluated as "A". B: One of the processability or bleed-out resistance was evaluated as "A", and the other was evaluated as "B". C: One of the processability or bleed-out resistance was evaluated as "C".

[0129] <6. Usefulness of Human Body Models> For the molded bodies formed from the elastomer compositions obtained in each example and comparative example, the elasticity (feel) when a skilled person pressed the entire upper surface of the mold contact surface with the palm of their hand seven days after molding was classified according to the following criteria. Y: The feel was useful as a human body model. N: The feel was not useful as a human body model. Note that "a feel useful as a human body model" refers to the texture of relatively soft parts of the human body (for example, breasts or buttocks). The above "Y" means "Yes" and the above "N" means "No".

[0130] [Materials of the elastomer compositions used in the examples and comparative examples] The details of each component used in each example are shown below.

[0131] [Aromatic vinyl compound elastomers (A)] • (A1): Septon 4033 (trade name), manufactured by Kuraray Co., Ltd., SEEPS, hydrogenated triblock copolymer, a hydrogenated product of polystyrene-polyisoprene-polystyrene [styrene-derived polymer block content: 30% by mass], hydrogenation rate: 98 mol%, number average molecular weight: 90,000, viscosity in 10% by mass toluene solution (30°C): 50 mPa·s • (A2): Septon 4055 (trade name), manufactured by Kuraray Co., Ltd., SEEPS, hydrogenated triblock copolymer, a hydrogenated product of polystyrene-poly(1,3-butadiene / isoprene)-polystyrene [styrene-derived polymer block content: 30% by mass], hydrogenation rate: 98 mol%, number average molecular weight: 200,000, viscosity in 5% by mass toluene solution (30°C): 90 mPa·s

[0132] [Oil (Y)] ・(Y1): CARNATION®, manufactured by Sonneborn (CAS registration number 8042-47-5), paraffinic process oil, 100% purity (no polar solvents), kinematic viscosity (40°C): 11.9 mm ２ / s, specific gravity: 0.846

[0133] [Oil (Y'): Comparative component of Oil (Y)] • (Y'1): PW-90 (product name), manufactured by Idemitsu Kosan Co., Ltd., paraffin-based process oil, 100% purity (no polar solvents), kinematic viscosity (40°C): 90 mm ２ / s, specific gravity: 0.86

[0134] [Organic Additive (Z)] ・(Z1): Irganox 1010 (trade name), compound name: pentaerythritol tetrakis(3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate (molecular weight: 1178, polar groups: phenolic hydroxyl groups and ester bonds, number of polar groups per molecule: 8, number of phenolic hydroxyl groups per molecule: 4), manufactured by BASF, hindered phenol antioxidant. It was confirmed that 2.4 parts by mass of this organic additive (Z1) completely dissolves in 100 parts by mass of oil (Y1) at 160°C, 2.4 parts by mass completely dissolves in 100 parts by mass of oil (Y'1) at 160°C, and that precipitates form when 2.4 parts by mass dissolves in 100 parts by mass of oil (Y1) at 160°C and then the temperature is reduced to 50°C ± 5°C over 30 minutes (satisfying the aforementioned requirements, i.e., P > 0).

[0135] [Organic compound additive (Z'): Comparative component of bleed-out inhibitor (Z)] ・(Z'1): Irganox 1076 (trade name), compound name: octadecyl 3-(3,5-di-tert-butyl-4-hydroxyphenyl)propanoate (molecular weight: 531, polar groups: phenolic hydroxyl group and ester bond, number of polar groups per molecule: 2, number of phenolic hydroxyl groups per molecule: 1), manufactured by BASF, hindered phenol antioxidant, It was confirmed that 2.4 parts by mass of this organic additive (Z'1) completely dissolves in 100 parts by mass of oil (Y1) at 160°C, and that no precipitates form when the temperature is reduced to 50°C ± 5°C over 30 minutes after 2.4 parts by mass of this additive (Z'1) completely dissolves in 100 parts by mass of oil (Y1) at 160°C (i.e., P = 0).

[0136] • (Z'2): SUMILIZER GP (trade name), compound name: 6-tert-butyl-4-[3-[(2,4,8,10-tetra-tert-butyldibenzo[d,f][1,3,2]dioxaphosfepin-6-yl)oxy]propyl]-2-methylphenol (molecular weight: 661, polar groups: phenolic hydroxyl group and ether bond to dioxaphosfepin, number of polar groups per molecule: 2, number of phenolic hydroxyl groups per molecule: 1), manufactured by Sumitomo Chemical Co., Ltd., hindered phenol antioxidant. It was confirmed that 2.4 parts by mass of this organic additive (Z'2) completely dissolves in 100 parts by mass of oil (Y1) at 160°C, and that after 2.4 parts by mass of this additive completely dissolves in 100 parts by mass of oil (Y'1) at 160°C, no precipitate is formed when the temperature is reduced to 50°C ± 5°C over 30 minutes (i.e., the aforementioned requirements are not met, i.e., P = 0).

[0137] [Pigments (B)] ・(B1): Powdered colorant for synthetic resins manufactured by Towa Chemical Co., Ltd. (contains red pigment, orange pigment, and titanium dioxide)

[0138] [First Example] <Example 1-1> (Production of Elastomer Composition) Using a twin-screw extruder (bore diameter 46 mm, L / D = 46), an aromatic vinyl compound elastomer (A), oil (Y), a bleed-out inhibitor (Z), and a titanium dioxide-based pigment in the formulations shown in Table 1 were mixed and melt-kneaded at 200°C to obtain a molten kneaded product of the elastomer composition. The specific gravity of the molten kneaded product of the elastomer composition at 25°C was 0.85.

[0139] (Manufacturing of Molded Body) The molded body was manufactured as follows. Specifically, 3000 g of molten and kneaded elastomer composition was placed in a melting apparatus (FlexMelt (trademark), model: FM-8, manufactured by VALCO MELTON), and heated at 170°C (±5°C) for 50 minutes to melt it. After it had completely melted, the molten material was poured into a circular aluminum mold measuring φ10 cm × height 3 cm. The mold was then cooled by blowing air for approximately 90 minutes. After confirming that the molten material had cooled to room temperature and completely solidified, the molded body was removed from the mold. The evaluation described above was performed using the obtained molded body. The results are shown in Table 1.

[0140] <Comparative Example 1-1 and Examples 1-2 to 1-5, and Comparative Examples 2-1 to 2-6> Except for changing the formulation as shown in Table 1, a molten compound of the elastomer composition was produced in the same manner as in Example 1-1. Furthermore, a molded article was produced using the obtained molten compound of the elastomer composition in the same manner as in Example 1-1. The evaluation described above was performed using the obtained molded article. The results are shown in Table 1.

[0141] <Comparative Examples 3-1 to 3-6, and Comparative Examples 4-1 to 4-6> Except for the changes in formulation as shown in Table 2, a molten compound of the elastomer composition was produced in the same manner as in Example 1-1. Furthermore, a molded article was produced using the obtained molten compound of the elastomer composition in the same manner as in Example 1-1. The evaluation described above was performed using the obtained molded article. The results are shown in Table 2.

[0142]

[0143]

[0144] [Second Example] The second example differs from the first example in that the amount of component (Y) or component (Y) relative to 100 parts by mass of component (A) in the elastomer composition is different. This will be explained below.

[0145] <Example 5-1> A molten compound of the elastomer composition was produced in the same manner as in Example 1-1, except that the formulation was changed as shown in Table 3. The specific gravity of the molten compound of the elastomer composition at 25°C was 0.85. Furthermore, a molded article was produced using the obtained molten compound of the elastomer composition in the same manner as in Example 1-1. The evaluation described above was performed using the obtained molded article. The results are shown in Table 3.

[0146] <Comparative Example 5-1 and Examples 5-2 to 5-5, and Comparative Examples 6-1 to 6-6> Except for changing the formulation as shown in Table 3, a molten compound of the elastomer composition was produced in the same manner as in Example 5-1. Furthermore, a molded article was produced using the obtained molten compound of the elastomer composition in the same manner as in Example 5-1. The evaluation described above was performed using the obtained molded article. The results are shown in Table 3.

[0147] <Comparative Examples 7-1 to 7-6, and Comparative Examples 8-1 to 8-6> Except for the changes in formulation as shown in Table 4, a molten compound of the elastomer composition was produced in the same manner as in Example 5-1. Furthermore, a molded article was produced using the obtained molten compound of the elastomer composition in the same manner as in Example 5-1. The evaluation described above was performed using the obtained molded article. The results are shown in Table 4.

[0148]

[0149]

[0150] As shown in Tables 1 to 4, the elastomer compositions in the examples were found to have superior processability for molded articles and excellent bleed-out resistance compared to the elastomer compositions in the comparative examples, thus demonstrating superior manufacturability for molded articles.

[0151] Furthermore, a comparison between Examples 1-1 to 1-4 and Example 1-5 in Table 1, and a comparison between Examples 5-1 to 5-4 and Example 5-5 in Table 3, revealed that by reducing the amount of bleed-out inhibitor (Z) used, it is possible to provide a molded body with superior usability as a human body model.

[0152] The elastomer composition of the present invention offers excellent manufacturability and can provide molded articles with low hardness, making these molded articles useful in various fields where elasticity, impact resistance, vibration damping, safety, and tactile qualities such as feel are required. Furthermore, the elastomer composition of the present invention offers excellent manufacturability and can provide molded articles with suppressed bleed-out and superior tactile qualities, making these molded articles useful in various fields where tactile qualities such as feel are required.

Claims

1. An elastomer composition comprising an aromatic vinyl compound-based elastomer (A) and having a kinematic viscosity of 50 mm at 40°C. ２ The elastomer composition comprises an oil (Y) with a concentration of less than 1 / s and an organic additive (Z) soluble in the oil (Y) at 160°C, wherein the amount of the oil (Y) per 100 parts by mass of the aromatic vinyl compound elastomer (A) is in the range of 500 parts by mass to 4000 parts by mass, and the content of the organic additive (Z) in the elastomer composition is 0.5% by mass or more, and the organic additive (Z) has the following requirements: the mass S of the second solid when a 2.34% by mass solution of the organic additive (Z) using a specific solvent at 160°C that may contain a first solid is brought to 50°C ± 5°C over 30 minutes. ５０ From the mass S of the first solid component １６０ The effective precipitate amount P, which can be calculated by subtracting the specified solvent, is greater than 0, where the specified solvent has CAS registration number 8042-47-5 and a kinematic viscosity at 40°C of 10.8 to 13.6 mm². ２ An elastomer composition that satisfies the following conditions: it is a white mineral oil with a density of / s and a specific gravity of 0.829 to 0.

859.

2. The elastomer composition according to claim 1, wherein the amount of the organic additive (Z) per 1 part by mass of the oil (Y) is 0.008 parts by mass or more.

3. The mass S of the first solid component. １６０ The elastomer composition according to claim 1, wherein is 0.

4. The elastomer composition according to claim 1, wherein the organic additive (Z) is a polar group-containing organic compound.

5. The elastomer composition according to claim 4, wherein the polar group-containing organic compound has four or more polar groups per molecule.

6. The elastomer composition according to claim 4, wherein the polar group-containing organic compound is at least one selected from phenolic hydroxyl group-containing organic compounds and their radical reaction products.

7. The elastomer composition according to claim 6, wherein the phenolic hydroxyl group-containing organic compound has two or more phenolic hydroxyl groups per molecule.

8. The elastomer composition according to claim 1, wherein the organic additive (Z) comprises at least one selected from pentaerythritol tetrakis(3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate and its radical reaction products.

9. The elastomer composition according to claim 1, wherein the content of the organic additive (Z) in the elastomer composition is 10% by mass or less.

10. The elastomer composition according to claim 1, wherein the aromatic vinyl compound elastomer (A) is a styrene-ethylene-ethylene-propylene-styrene copolymer.

11. A molded article formed from the elastomer composition according to any one of claims 1 to 10.

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