Resin composition

Abstract

A resin composition comprising a block copolymer (I), a block copolymer (II), and a tackifying resin (X), wherein: said (I) is a triblock copolymer that includes a polymeric block (A1) including an α-methylstyrene unit and a polymeric block (B1) including a conjugated diene compound unit, and that has a binding mode in which blocks of (A1) and (B1) are sequentially bonded; said (II) is a copolymer that includes a polymeric block (A2) including an α-methylstyrene unit and a polymeric block (B2) including a conjugated diene compound unit, and that has a diblock copolymer structure having a binding mode in which blocks of (A2) and (B2) are sequentially bonded; said (I) and (II) are contained at a prescribed mass ratio; and said (I) and (II) are each a hydrogenated block copolymer and each have a prescribed hydrogenation rate.

Description

resin composition

[0001] The present invention relates to a resin composition comprising a block copolymer.

[0002] Various polymers are used as base polymers for hot-melt adhesives, including ethylene-vinyl acetate copolymers, block copolymers of styrene and conjugated diene compounds and their hydrogenated derivatives, ethylene-α-olefin copolymers, and polyester resins. In particular, block copolymers containing styrene and conjugated diene compounds are suitable for use as adhesives in disposable sanitary materials and surface protective films because they have a long adhesive bonding time from the time the adhesive is applied to the adherend until bonding, and offer a relatively good balance between holding power and adhesion when used as an adhesive. For example, Patent Document 1 discloses an adhesive composition using a linear block copolymer such as polystyrene-polybutadiene-polystyrene or polystyrene-polyisoprene-polystyrene. Patent Document 2 also discloses (polystyrene-polybutadiene) ｎ A hot-melt adhesive composition using branched-chain block copolymer of X is disclosed. Furthermore, Patent Document 3 proposes an adhesive containing a block copolymer of α-methylstyrene and a conjugated diene in order to enhance cohesive force (holding force) under high-temperature conditions.

[0003] Japanese Patent Publication No. 45-41518, Japanese Patent Publication No. 56-49958, International Publication No. 2002 / 040611

[0004] However, there is still room for improvement in resin compositions containing block copolymers comprising α-methylstyrene and conjugated diene compounds. There is a need for resin compositions that ensure good coatability while exhibiting a high interfacial fracture temperature and high high-temperature retention for adherends of various materials (e.g., metallic materials and multiple types of resin materials). For example, when the resin composition is processed into a sheet with an area of ​​25 mm x 25 mm, and a plate-shaped adherend with a load of 1 kg is attached to the sheet and suspended, the adherend will not fall for 10,000 minutes or more in an environment of 70°C, or for 240 minutes or more in an environment of 80°C.

[0005] The object of the present invention is to solve the above problems and provide a resin composition that has high meltability, a high interfacial fracture temperature, and exhibits high high-temperature retention for adherends of various materials.

[0006] The present inventors, through diligent research to solve the above problems, have discovered that a resin composition containing a block copolymer comprising α-methylstyrene and a conjugated diene compound, wherein multiple types of block copolymers with different structures are contained in a predetermined ratio, can solve the above problems, leading to the present invention. That is, the present invention is as follows. [1] A resin composition comprising a block copolymer (I), a block copolymer (II), and a tackifying resin (X), wherein the block copolymer (I) comprises a polymer block (A1) containing α-methylstyrene units and a polymer block (B1) containing conjugated diene compound units, and the polymer block (A1) and the polymer block (B1) are a triblock copolymer represented as A1-B1-A1; the block copolymer (II) comprises a polymer block (A2) containing α-methylstyrene units and a polymer block (B2) containing conjugated diene compound units, and the polymer block (A2) and the polymer block (B2) are a diblock copolymer represented as A2-B2; the block copolymer (I) and the block copolymer (II) are contained in a mass ratio of (I):(II) = 96:4 to 80:20; and the block copolymer (I) and the block copolymer (II) are hydrogenated block copolymers with a hydrogenation rate of 50 mol% or more and 100 mol% or less. [2] The resin composition according to [1], wherein the total content of polymer block (A1) and polymer block (A2) in 100% by mass of the total of block copolymer (I) and block copolymer (II) is 5% by mass or more and 55% by mass or less. [3] The resin composition according to [1] or [2], wherein the melt viscosity at 180°C is less than 50,000 mPa·s. [4] The resin composition according to any one of [1] to [3], wherein it does not contain a surfactant, or further contains a surfactant, and the content of the surfactant is greater than 0 ppm by mass and 5,000 ppm by mass or less, based on 100% by mass of the resin composition. [5] The resin composition according to any one of [1] to [4], wherein the content of the tackifying resin (X) is 10% by mass or more and 50% by mass or less, based on 100% by mass of the resin composition.[6] The resin composition according to any one of [1] to [5] above, wherein at least one conjugated diene compound unit selected from the group consisting of the conjugated diene compound units of the polymer block (B1) and the conjugated diene compound units of the polymer block (B2) is a structural unit derived from butadiene. [7] The resin composition according to any one of [1] to [6] above, further comprising a plasticizer (Y). [8] The resin composition according to any one of [1] to [7] above, which is an adhesive composition. [9] An adhesive tape using the adhesive composition according to [8] above.

[0007] The present invention provides a resin composition that has high meltability, a high interfacial fracture temperature, and exhibits high high-temperature retention for adherends of various materials.

[0008] The following describes resin compositions according to one or more embodiments of the present invention (hereinafter also referred to as "embodiments of the present invention"). However, the embodiments shown below are illustrative examples for realizing the technical concept of the present invention, and the present invention is not limited to the following description. In addition, preferred embodiments of the present invention are shown in this specification, but combinations of two or more individual preferred embodiments are also preferred embodiments. When there are several numerical ranges for matters indicated by numerical ranges, a preferred embodiment can be made by selectively combining the lower and upper limits of those ranges. In this specification, when a numerical range is described as "XX to YY", it means "XX or more and YY or less". In addition, in this specification, hydrogenation may be referred to as "hydrogenation", hydrogenated products as "hydrogenated products", and the hydrogenation rate as "hydrogenation rate".

[0009] [Resin Composition] The resin composition according to the embodiment of the present invention is a resin composition comprising a block copolymer (I), a block copolymer (II), and a tackifying resin (X), wherein the block copolymer (I) comprises a polymer block (A1) containing α-methylstyrene units and a polymer block (B1) containing conjugated diene compound units, and the polymer block (A1) and the polymer block (B1) are a triblock copolymer represented as A1-B1-A1, the block copolymer (II) comprises a polymer block (A2) containing α-methylstyrene units and a polymer block (B2) containing conjugated diene compound units, and the polymer block (A2) and the polymer block (B2) are a diblock copolymer represented as A2-B2, the block copolymer (I) and the block copolymer (II) are contained in a mass ratio of (I):(II) = 96:4 to 80:20, and the block copolymer (I) and the block copolymer (II) are hydrogenated block copolymers with a hydrogenation rate of 50 mol% or more and 100 mol% or less.

[0010] The resin composition according to the embodiment of the present invention exhibits high meltability, a high interfacial fracture temperature, and high high-temperature retention for adherends of various materials. The reasons for this are not limited to the following, but are considered to be the following: The resin composition according to the embodiment of the present invention contains block copolymer (I) in a predetermined high mass proportion. The polymer block (A1) contained in block copolymer (I) contains α-methylstyrene units with a high glass transition temperature. Therefore, the high-temperature retention for adherends is increased even without using polymer blocks (A1) with high molecular weight, and the increase in melt viscosity due to the high molecular weight of polymer blocks (A1) is avoided. In addition, it is believed that the resin composition exhibits good adhesive properties to various adherends while achieving the above-mentioned advantages by containing block copolymer (II) in a predetermined low mass proportion.

[0011] In this specification, "α-methylstyrene unit" refers to a structural unit derived from α-methylstyrene, the monomer before polymerization. "Conjugated diene compound unit" refers to a structural unit derived from a conjugated diene compound, the monomer before polymerization. Furthermore, in this specification, structural units derived from aromatic vinyl compounds such as α-methylstyrene and styrene may be collectively referred to as "aromatic vinyl blocks." Similarly, structural units derived from conjugated diene compounds such as butadiene and isoprene may be collectively referred to as "conjugated diene blocks."

[0012] <Block Copolymer (I) and Block Copolymer (II)> The block copolymer (I) contained in the resin composition according to the embodiment of the present invention comprises a polymer block (A1) containing α-methylstyrene units and a polymer block (B1) containing conjugated diene compound units, wherein the polymer block (A1) and the polymer block (B1) are a triblock copolymer represented as A1-B1-A1. The block copolymer (II) contained in the resin composition according to the embodiment of the present invention comprises a polymer block (A2) containing α-methylstyrene units and a polymer block (B2) containing conjugated diene compound units, wherein the polymer block (A2) and the polymer block (B2) are a diblock copolymer represented as A2-B2.

[0013] Furthermore, block copolymer (I) and block copolymer (II) are contained in the resin composition in a mass ratio of (I):(II) = 96:4 to 80:20. This mass ratio of block copolymer (I) to block copolymer (II) within this range ensures both meltable properties, heat resistance, and high high-temperature retention on various substrate materials. Additionally, block copolymer (I) and block copolymer (II) are hydrogenated block copolymers, with a hydrogenation rate of 50 mol% to 100 mol%. This hydrogenation rate of 50 mol% to 100 mol% results in good heat resistance and a high interfacial fracture temperature. It also facilitates improved weather resistance.

[0014] Polymer block (A1) and polymer block (A2) contain α-methylstyrene units. From the viewpoint of increasing the high-temperature retention capacity of the resulting resin composition, the α-methylstyrene units in 100% by mass of polymer block (A1) and polymer block (A2) are each preferably 50% to 100% by mass, more preferably 70% to 100% by mass, and even more preferably 90% to 100% by mass, respectively. The content of α-methylstyrene units in the total 100% by mass of polymer block (A1) and polymer block (A2) is each preferably 50% to 100% by mass, more preferably 70% to 100% by mass, and even more preferably 90% to 100% by mass, respectively.

[0015] Furthermore, polymer block (A1) and polymer block (A2) may each independently contain monomer units other than α-methylstyrene units, as long as this does not impair the spirit of the present invention. The monomers are not limited to any monomers that can be anionically polymerized in general, but for example, vinyl aromatic compounds such as styrene, o-methylstyrene, m-methylstyrene, p-methylstyrene, 1,3-dimethylstyrene, and diphenylethylene, and conjugated diene compounds such as butadiene, isoprene, and 2,3-dimethyl-1,3-butadiene are preferred. It is more preferable that the monomer other than α-methylstyrene units is at least one selected from the group consisting of styrene, p-methylstyrene, butadiene, and isoprene. The form of polymer block (A1) and polymer block (A2) when they contain other monomers is not particularly limited and may be random or tapered.

[0016] The polystyrene-based number-average molecular weight (Mn) of polymer block (A1) and polymer block (A2) is preferably 500 to 300,000, more preferably 1,000 to 100,000, more preferably 2,000 to 50,000, and more preferably 3,000 to 10,000.

[0017] In the resin composition according to the embodiment of the present invention, the total content of polymer block (A1) and polymer block (A2) in 100% by mass of the total of block copolymer (I) and block copolymer (II) is preferably 5% by mass or more and 55% by mass or less, more preferably 10% by mass or more and 45% by mass, even more preferably 15% by mass or more and 35% by mass or less, even more preferably 20% by mass or more and 35% by mass or less, even more preferably 22% by mass or more and 33% by mass or less, and particularly preferably 24% by mass or more and 31% by mass or less, from the viewpoint of easily improving the heat resistance and high temperature retention of the obtained resin composition.

[0018] Polymer block (B1) and polymer block (B2) contain conjugated diene compound units. Examples of conjugated diene compounds include butadiene, isoprene, and 2,3-dimethyl-1,3-butadiene, each independently. These may be used individually or in combination of two or more. Among the conjugated diene compounds, at least one selected from the group consisting of butadiene and isoprene is preferred, and butadiene is more preferred. In the resin composition according to the embodiment of the present invention, at least one conjugated diene compound unit selected from the group consisting of the conjugated diene compound units of polymer block (B1) and the conjugated diene compound units of polymer block (B2) is a structural unit derived from butadiene. When the above conjugated diene compound unit is a structural unit derived from butadiene, heat resistance is improved and the interfacial fracture temperature is easily increased. Alternatively, both the conjugated diene compound units of polymer block (B1) and the conjugated diene compound units of polymer block (B2) may be structural units derived from butadiene.

[0019] Polymer block (B1) and polymer block (B2) contain conjugated diene compound units. From the viewpoint of increasing the meltable properties of the resulting resin composition, the content of conjugated diene compound units in 100% by mass of polymer block (B1) and the content of conjugated diene compound units in 100% by mass of polymer block (B2) are, independently, preferably 50% by mass or more and 100% by mass or less, more preferably 70% by mass or more and 100% by mass or less, and even more preferably 90% by mass or more and 100% by mass or less, and may be 100% by mass.

[0020] In the resin composition according to the embodiment of the present invention, the content of conjugated diene compound units in the total 100% by mass of polymer block (B1) and polymer block (B2) is preferably 50% by mass or more and 100% by mass or less, more preferably 70% by mass or more and 100% by mass or less, and even more preferably 90% by mass or more and 100% by mass or less.

[0021] Furthermore, polymer block (B1) and polymer block (B2) may each independently contain other anionic polymerizable monomers other than conjugated diene compound units, as long as this does not impair the spirit of the present invention. However, α-methylstyrene is not included among these other anionic polymerizable monomers. By including an anionic polymerizable monomer other than α-methylstyrene in at least one of polymer block (B1) and polymer block (B2), the reduction in cohesive force caused by α-methylstyrene units can be suppressed. The form of polymer block (B1) and polymer block (B2) when they contain other anionic polymerizable monomers is not particularly limited and may be random or tapered.

[0022] The number-average molecular weight (Mn) of polymer block (B1) and polymer block (B2) in terms of polystyrene is preferably 10,000 to 400,000, and more preferably 15,000 to 200,000, independently of each other.

[0023] The amount of vinyl bonding in polymer block (B1) and polymer block (B2) is preferably 10 mol% to 95 mol%, more preferably 15 mol% to 80 mol%, more preferably 20 mol% to 70 mol%, more preferably 35 mol% to 60 mol%, and even more preferably 40 mol% to 50 mol%. The amount of vinyl bonding is measured by the method described in the examples.

[0024] In the resin composition according to an embodiment of the present invention, the total content of the polymer block (B1) and the polymer block (B2) in a total of 100% by mass of the block copolymer (I) and the block copolymer (II) is preferably 45% by mass or more and 95% by mass or less, more preferably 55% by mass or more and 90% by mass or less, still more preferably 65% by mass or more and 85% by mass or less, even more preferably 65% by mass or more and 80% by mass or less, even more preferably 67% by mass or more and 78% by mass or less, particularly preferably 69% by mass or more and 76% by mass or less, from the viewpoint of facilitating the enhancement of the meltability of the resulting resin composition.

[0025] In the above resin composition, the ratio [(A1) + (A2)] / [(B1) + (B2)] of the total mass of the polymer block (A1) and the polymer block (A2) to the total mass of the polymer block (B1) and the polymer block (B2) is preferably 5 / 95 to 55 / 45, more preferably 10 / 90 to 45 / 55, still more preferably 15 / 85 to 35 / 65, even more preferably 20 / 80 to 35 / 65, even more preferably 22 / 78 to 33 / 67, particularly preferably 24 / 76 to 31 / 69, from the viewpoint of the balance between the meltability, heat resistance, and high-temperature retention of the resulting resin composition.

[0026] The polymer block (A1) constituting the block copolymer (I) and the polymer block (A2) constituting the block copolymer (II) may be the same or different. Also, the polymer block (B1) constituting the block copolymer (I) and the polymer block (B2) constituting the block copolymer (II) may be the same or different.

[0027] Furthermore, block copolymer (I) and block copolymer (II) are hydrogenated as described above. The hydrogenation rate of block copolymer (I) and block copolymer (II) is at least 50 mol% to 100 mol%, preferably 70 mol% to 100 mol%, more preferably 90 mol% to 99.5 mol%, even more preferably 95 mol% to 99.5 mol%, and particularly preferably 97 mol% to 99.5 mol%. By having the above hydrogenation rate within the above range, it becomes easier to improve adhesive performance, heat degradation resistance, weather resistance, etc. Also, it is preferable that block copolymer (I) and block copolymer (II) are hydrogenated, with a polymer block (B1) containing conjugated diene compound units contained in block copolymer (I) and a polymer block (B2) containing conjugated diene compound units contained in block copolymer (II). The hydrogenation rate of block copolymer (I) and block copolymer (II) is determined by the nuclear magnetic resonance spectrum ( １ It can be calculated using 1H-NMR spectroscopy (H-NMR) measurement.

[0028] Furthermore, one or both of block copolymer (I) and block copolymer (II) may contain a functional group such as a carboxyl group, a hydroxyl group, an acid anhydride, an amino group, or an epoxy group in at least one of the group consisting of the main chain, side chains, and molecular ends in the molecular chain, as long as the spirit of the present invention is not impaired.

[0029] The weight average molecular weight (Mw) of the block copolymer (I) and the block copolymer (II) in terms of polystyrene can be appropriately adjusted according to the intended use and the like. The weight average molecular weight (Mw) of the block copolymer (I) is preferably 10,000 or more and 2,000,000 or less, more preferably 15,000 or more and 1,000,000 or less, still more preferably 20,000 or more and 500,000 or less, even more preferably 25,000 or more and 250,000 or less, even more preferably 35,000 or more and 150,000 or less, and particularly preferably 50,000 or more and 100,000 or less. The weight average molecular weight (Mw) of the block copolymer (II) is preferably 5,000 or more and 1,000,000 or less, more preferably 7,500 or more and 500,000 or less, still more preferably 10,000 or more and 250,000 or less, even more preferably 20,000 or more and 100,000 or less, and particularly preferably 25,000 or more and 50,000 or less.

[0030] As a method for producing the block copolymer (I) and the block copolymer (II) used in the resin composition according to the embodiment of the present invention, synthesis is possible by anionic polymerization. Specific synthesis examples of the block copolymer (I) are shown in the following (1) and (2). (1) A method of obtaining an A-B-A type block copolymer by polymerizing a conjugated diene compound using a dianionic initiator in a tetrahydrofuran solvent and then sequentially polymerizing α-methylstyrene under a temperature condition of -78°C (Macromolecules, (1969), 2(5), 453-458). (2) A method of polymerizing α-methylstyrene at a specific concentration at a specific temperature in the presence of a specific concentration of a polar compound using an organolithium compound as a polymerization initiator in a nonpolar solvent, polymerizing a conjugated diene compound with the resulting living polyα-methylstyryl lithium, and then adding a coupling agent to obtain an A-B-A type block copolymer.

[0031] For the block copolymer (I), the method (2) above is particularly preferably adopted as a more preferable method. Specifically, the block copolymer (I) is produced by the method described in the examples.

[0032] Polymerization initiators used during polymerization are organolithium compounds, such as monolithium compounds like n-butyllithium, sec-butyllithium, and tert-butyllithium, and dilithium compounds like tetraethylenedilithium. These compounds may be used individually or in combination of two or more.

[0033] The solvents used during polymerization are nonpolar solvents, such as aliphatic hydrocarbons like cyclohexane, methylcyclohexane, n-hexane, and n-heptane, and aromatic hydrocarbons like benzene, toluene, and xylene. These may be used individually or in combination of two or more. The polar compounds used during polymerization are compounds that do not have functional groups (such as hydroxyl groups or carbonyl groups) that react with anionic species, and that have heteroatoms such as oxygen atoms and nitrogen atoms in their molecules. Examples include diethyl ether, monoglyme, tetramethylethylenediamine, dimethoxyethane, and tetrahydrofuran. These compounds may be used individually or in combination of two or more.

[0034] The concentration of the polar compound in the reaction system is preferably in the range of 0.01% by mass to 10% by mass, more preferably in the range of 0.05% by mass to 5% by mass, and even more preferably in the range of 0.1% by mass to 3% by mass, from the viewpoint of controlling the amount of vinyl bonds in polymer block (B1) and polymer block (B2). The concentration of α-methylstyrene in the reaction system is preferably in the range of 1% by mass to 50% by mass, more preferably in the range of 3% by mass to 30% by mass, and even more preferably in the range of 5% by mass to 10% by mass, from the viewpoint of polymerizing α-methylstyrene with a high polymerization conversion rate and the viscosity of the reaction solution in the later stages of polymerization.

[0035] The polymerization conversion rate mentioned above refers to the percentage of unpolymerized α-methylstyrene that has been converted to living poly-α-methylstyryllithium. In the resin composition according to the embodiment of the present invention, this percentage is preferably 70% to 100% and more preferably 85% to 99% from the viewpoint of ease of manufacture.

[0036] The polymerization temperature for α-methylstyrene is preferably in the range of -30°C to 30°C, more preferably -20°C to 10°C, and even more preferably -15°C to 0°C. By setting the polymerization temperature to 30°C or lower, α-methylstyrene polymerizes with a high polymerization conversion rate, and the proportion of the resulting living poly-α-methylstyryllithium that is deactivated is also small, suppressing the inclusion of unpolymerized α-methylstyrene in the resulting block copolymer and preventing deterioration of its physical properties. Furthermore, by setting the polymerization temperature to -30°C or higher, the reaction solution can be stirred without becoming highly viscous in the later stages of α-methylstyrene polymerization, and the costs required to maintain a low temperature are not increased, making it economically preferable.

[0037] After the formation of living poly-α-methylstyryllithium, the conjugated diene compound is then polymerized. There are no particular restrictions on the method of adding the conjugated diene compound to the living poly-α-methylstyryllithium solution; it may be added directly to the living poly-α-methylstyryllithium solution or diluted with a solvent before addition. As for the method of adding the conjugated diene compound to the living poly-α-methylstyryllithium solution after diluting with a solvent, the conjugated diene compound may be added first and then diluted with the solvent, or the conjugated diene compound and solvent may be added simultaneously, or the conjugated diene compound may be added after dilution with the solvent. Preferably, an amount of the conjugated diene compound corresponding to 1 molar equivalent to 100 molar equivalents, preferably 5 molar equivalents to 50 molar equivalents, relative to living poly-α-methylstyryllithium is added to the living poly-α-methylstyryllithium solution, then diluted with a solvent, and the remaining conjugated diene compound is added, and the polymerization reaction is carried out at a temperature above 30°C, preferably in the temperature range of 40°C to 80°C.

[0038] Examples of solvents that can be used for dilution include aliphatic hydrocarbons such as cyclohexane, methylcyclohexane, n-hexane, and n-heptane, and aromatic hydrocarbons such as benzene, toluene, and xylene. These solvents may be used individually or in combination of two or more.

[0039] A triblock copolymer can be produced by reacting a coupling agent with a living polymer obtained by copolymerizing living poly-α-methylstyryllithium with a conjugated diene compound. Furthermore, by adjusting the amount of coupling agent used, a mixture containing triblock copolymer and diblock copolymer can be obtained. Examples of coupling agents include phenyl benzoate, methyl benzoate, ethyl benzoate, methyl acetate, ethyl acetate, methyl pivalate, ethyl pivalate, phenyl pivalate, α,α'-dichloro-o-xylene, α,α'-dichloro-m-xylene, α,α'-dichloro-p-xylene, bis(chloromethyl) ether, dibromomethane, diiodomethane, dimethyl phthalate, dichlorodimethylsilane, dichlorodiphenylsilane, trichloromethylsilane, tetrachlorosilane, and divinylbenzene.

[0040] When hydrogenating a triblock copolymer or a mixture of a triblock copolymer and a diblock copolymer obtained by reacting a living polymer with a coupling agent, the coupling reaction can be stopped by adding active hydrogen compounds such as alcohols, carboxylic acids, or water as needed, and then hydrogenated in an inert organic solvent in the presence of a hydrogenation catalyst according to known methods to obtain a hydrogenated block copolymer.

[0041] Unhydrogenated block copolymers can be subjected to hydrogenation without replacing the solvent used in their production. The hydrogenation reaction can be carried out, for example, in the presence of a hydrogenation catalyst such as a Ziegler catalyst containing an alkylaluminum compound and transition metals such as cobalt and nickel, at a reaction temperature of 20°C to 100°C and a hydrogen pressure of 1 kg / cm². ２ More than 100kg / cm ２ This can be done under the following conditions.

[0042] Block copolymers (I) and block copolymers (II) obtained by the above method are preferably used, but in particular, from the viewpoint of adhesive performance, it is desirable to obtain them by using an organolithium compound as an initiator in a nonpolar solvent, polymerizing α-methylstyrene at a concentration of 5 to 50% by mass in the presence of a polar compound at a concentration of 0.1 to 10% by mass at a temperature of -30 to 30°C to form polymer block (A1) or (A2), then polymerizing 1 to 100 molar equivalents of a conjugated diene compound relative to living poly-α-methylstyryllithium, and then polymerizing the remaining conjugated diene compound at a temperature above 30°C to form polymer block (B1) or (B2).

[0043] <Content of block copolymer (I) and block copolymer (II) in the resin composition> As described above, block copolymer (I) and block copolymer (II) are contained in the resin composition in a mass ratio of (I):(II) = 96:4 to 80:20. The mass ratio (I):(II) is preferably 95:5 to 80:20, more preferably 95:5 to 82:18, even more preferably 95:5 to 84:16, and even more preferably 95:5 to 85:15, from the viewpoint of balancing high meltability, high heat resistance and high temperature retention.

[0044] In the resin composition according to this embodiment, the total content of block copolymer (I) and block copolymer (II) in 100% by mass is preferably 10% by mass or more and 55% by mass or less, more preferably 10% by mass or more and 50% by mass or less, even more preferably 15% by mass or more and 50% by mass or less, and even more preferably 20% by mass or more and 50% by mass or less.

[0045] In 100% by mass of the resin composition according to this embodiment, the content of block copolymer (I) is preferably 8% by mass or more and 52% by mass or less, more preferably 8% by mass or more and 47% by mass or less, even more preferably 10% by mass or more and 47% by mass or less, and even more preferably 16% by mass or more and 47% by mass or less.

[0046] In 100% by mass of the resin composition according to this embodiment, the content of block copolymer (II) is preferably 0.5% by mass or more and 11% by mass or less, more preferably 0.5% by mass or more and 10% by mass or less, even more preferably 0.8% by mass or more and 10% by mass or less, and even more preferably 1% by mass or more and 10% by mass or less.

[0047] The resin composition according to the embodiment of the present invention may or may not contain a block copolymer (III) different from block copolymer (I) and block copolymer (II). Block copolymer (III) is a block copolymer comprising a polymer block (A3) that does not contain α-methylstyrene units and a polymer block (B3) that contains conjugated diene compound units. Polymer block (A3) contains at least one monomer unit selected from the group consisting of styrene, o-methylstyrene, m-methylstyrene, p-methylstyrene, 1,3-dimethylstyrene, and diphenylethylene. These may be used alone or in combination of two or more. Polymer block (B3) contains conjugated diene compound units. Examples of conjugated diene compounds include butadiene, isoprene, and 2,3-dimethyl-1,3-butadiene. These may be used alone or in combination of two or more. Among the conjugated diene compounds, at least one selected from the group consisting of butadiene and isoprene is preferred. Block copolymers (III) include diblock copolymers represented by A3-B3, triblock copolymers represented by A3-B3-A3, tetrablock copolymers represented by A3-B3-A3-B3, and (A3-B3) ｎExamples include star-shaped copolymers represented by X (where X represents a coupling agent residue). These block copolymers (III) may be used individually or as a mixture of two or more. When the resin composition according to the embodiment of the present invention contains block copolymer (III), the content of block copolymer (III) in 100% by mass of the resin composition according to this embodiment is preferably 5% by mass or more and 99% by mass or less, more preferably 30% by mass or more and 98% by mass or less. Even more preferably 50% by mass or more and 97% by mass or less, and even more preferably 70% by mass or more and 96% by mass or less.

[0048] <Tackifying Resin (X)> The resin composition according to the embodiment of the present invention contains at least one tackifying resin (X) in addition to the block copolymers (I) and (II) described above. The tackifying resin (X) that can be used in the resin composition according to the embodiment of the present invention is one that has been conventionally used as a resin to impart tackiness to adhesives, and is preferably at least one selected from the group consisting of rosin resins, terpene resins, coumarone resins, xylene resins, phenol resins, and hydrocarbon resins, with hydrocarbon resins or terpene resins being more preferred. More specifically, examples include coumarone-indene resin, phenol resin, p-t-butylphenol-acetylene resin, phenol-formaldehyde resin, polyterpene resin, xylene-formaldehyde resin, synthetic polyterpene resin, aromatic hydrocarbon resin (aromatic petroleum resin), aliphatic cyclic hydrocarbon resin (aliphatic cyclic petroleum resin), oligomers of monoolefins and diolefins, hydrocarbon resins, hydrogenated hydrocarbon resins, polybutene, polyhydric alcohol esters of rosin, hydrogenated rosin, hydrogenated wood rosin, and esters of hydrogenated rosin with monoalcohols or polyhydric alcohols. Particularly suitable tackifying resins include terpene resins, synthetic terpene resins, aromatically modified polyterpene resins, aliphatic saturated petroleum resins, rosin esters, disproportionated rosin esters, hydrogenated rosin esters, aliphatic petroleum resins (such as C5 aliphatic petroleum resins), and modified aliphatic petroleum resins. For rosin resins, at least one selected from the group consisting of rosin, disproportionated rosin, dimerized rosin, and other modified rosins, and esters of polyhydric alcohols such as glycol, glycerin, and pentaerythritol with rosin or modified rosins is preferred. For terpene resins, at least one selected from the group consisting of terpene resins, aromatically modified terpene resins, terpene phenol resins, hydrogenated terpene resins, hydrogenated aromatically modified terpene resins, and hydrogenated terpene phenol resins is preferred. Coumaron resin refers to a copolymer resin mainly composed of coumaron, indene, and styrene, with coumaron-indene resin being preferred. As the hydrocarbon resin (petroleum resin), aliphatic, aromatic, alicyclic, or aliphatic-aromatic copolymer hydrocarbon resin (petroleum resin) or hydrides thereof are preferred.Examples of tackifying resins used include, but are not limited to, the ARKON® resin series and PINECRYSTAL® resin series commercially available from Arakawa Chemical Industries, Ltd., the Imarv® resin series commercially available from Idemitsu Kosan Co., Ltd., the T-REZ® resin series commercially available from ENEOS Corporation, the YS® resin series and CLEARON® resin series commercially available from Yasuhara Chemical Co., Ltd., the Petrotac® resin series commercially available from Tosoh Corporation, the Kristalex® resin series and Endex® resin series commercially available from Eastman Ltd. The softening point of the tackifying resin (X) is not particularly limited as long as it does not impair the effects of the present invention, but is preferably 30°C to 200°C, more preferably 50°C to 180°C, and even more preferably 70°C to 160°C.

[0049] From the viewpoint of improving meltability, the tackifying resin (X) is preferably highly compatible with block copolymer (I) and block copolymer (II). Specifically, it is preferable that the resin obtained by mixing with block copolymer (I) and block copolymer (II) is transparent and does not become cloudy.

[0050] In the resin composition according to an embodiment of the present invention, the content of the tackifier resin (X) in 100% by mass of the resin composition (when two or more tackifier resins (X) are included, their total content) is preferably 10% by mass or more and 55% by mass or less, more preferably 10% by mass or more and 50% by mass or less, still more preferably 15% by mass or more and 50% by mass or less, and even more preferably 20% by mass or more and 50% by mass or less, from the viewpoint of the balance between melt viscosity and holding power. The content of the tackifier resin (X) (when two or more tackifier resins (X) are included, their total content) is not particularly limited as long as it is within a range that does not impair the object of the present invention, but is preferably 10% by mass or more and 1,000% by mass or less, more preferably 30% by mass or more and 700% by mass or less, still more preferably 50% by mass or more and 500% by mass or less, and even more preferably 70% by mass or more and 200% by mass or less, based on 100% by mass of the total mass of the block copolymers (I) and (II). Note that one type of tackifier resin (X) may be used, or two or more types may be used in combination.

[0051] <Plasticizer (Y)> From the viewpoint of facilitating the improvement of coating ease, the resin composition according to an embodiment of the present invention preferably further contains a plasticizer (Y). Examples of the plasticizer (Y) include biomass-derived plasticizers having no carboxy group, vegetable oils, and synthetic plasticizers.

[0052] Examples of the biomass-derived plasticizer having no carboxy group include compounds represented by the following general formula (1) and compounds represented by the following general formula (2).

[0053] However, in the general formula (1), n １ to n ３ are each independently 1 or 3, and R １ to R ６ are each independently a hydrogen atom or an unsubstituted hydrocarbon group, the total number of carbon atoms of R １ and R ２ is 14, the total number of carbon atoms of R ３ and R ４ is 14, the total number of carbon atoms of R ５ and R ６ is 14, R１ ~R ６ It may have a branched structure.

[0054] However, in general formula (2), n ４ and n ５ Each of these is independently either 1 or 3, and R ７ ~R １０ Each is independently a hydrogen atom or an unsubstituted hydrocarbon group, and R ７ and R ８ The total number of carbon atoms is 14, R ９ and R １０ The total number of carbon atoms is 14, R ７ ~R １０ It may have a branched structure.

[0055] Examples of vegetable oils include castor oil, cottonseed oil, linseed oil, safflower oil, rapeseed oil, soybean oil, Nagi oil, wood wax, pine oil, corn oil, peanut oil, olive oil, palm oil, palm olein, palm stearin, and other plant-derived oils, as well as transesterified oils, hydrogenated oils, or fractionated oils of these. Examples of synthetic plasticizers include oil-based softeners such as paraffinic, naphthenic, and aromatic process oils, mineral oil, and white oil; phthalic acid derivatives such as dioctyl phthalate and dibutyl phthalate; liquid co-oligomers of ethylene and α-olefins; liquid paraffin; polybutene; low molecular weight polyisobutylene; liquid polydienes such as liquid polybutadiene, liquid polyisoprene, liquid polyisoprene / butadiene copolymer, liquid styrene / butadiene copolymer, and liquid styrene / isoprene copolymer; and hydrogenated or modified versions thereof.

[0056] These can be used individually or in combination of two or more types.

[0057] The content of the plasticizer (Y) in the resin composition is not particularly limited as long as it does not impair the spirit of the present invention. However, from the viewpoint of improving ease of application, it is preferably 0% to 500% by mass, more preferably 0% to 300% by mass, even more preferably 5% to 200% by mass, and even more preferably 10% to 100% by mass, based on 100% by mass of the total mass of the block copolymers (I) and (II).

[0058] <Other Components> Furthermore, the resin composition according to the embodiment of the present invention may optionally contain additives other than block copolymers (I), (II), tackifying resin (X), and plasticizer (Y). Examples of additives include antioxidants such as phenolic antioxidants, sulfur-based antioxidants, and phosphorus-based antioxidants, light stabilizers, antistatic agents, mold release agents, flame retardants, foaming agents, pigments, dyes, whitening agents, and carbon fibers.

[0059] When the above additive is used, its content is preferably 0.5% to 5% by mass, more preferably 1% to 4% by mass, and even more preferably 1.5% to 3% by mass, based on 100% by mass of the resin composition.

[0060] Specific examples of antioxidants include, for example, 2,6-di-t-butyl-p-cresol, pentaerythryl-tetrakis[3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate], 1,3,5-trimethyl-2,4,6-tris(3,5-di-t-butyl-4-hydroxybenzyl)benzene, octadecyl-3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate, and triethylene glycol-bis[3-(3 [3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate], 2,4-bis-(n-octylthio)-6-(4-hydroxy-3,5-di-t-butylanilino)-1,3,5-triazine, 2,2-thio-diethylenebis[3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate], N,N'-hexamethylenebis(3,5-di-t-butyl-4-hydroxyhydrodinamamide), 3,5-di-t-butyl-4-H Phenolic antioxidants such as droxybenzylphosphonate-diethyl ester, tris-(3,5-di-t-butyl-4-hydroxybenzyl)isocyanurate, 3,9-bis{2-[3-(3-t-butyl-4-hydroxy-5-methylphenyl)propionyloxy]-1,1-dimethylethyl}-2,4,8,10-tetraoxaspiro[5,5]undecane, pentaerythrityltetrakis(3-laurylthiopropionate), Examples of antioxidants include sulfur-based antioxidants such as distearyl 3,3'-thiodipropionate, dilauryl 3,3'-thiodipropionate, and dimyristyl 3,3'-thiodipropionate, and phosphorus-based antioxidants such as trisnonylphenyl phosphite, tris(2,4-di-t-butylphenyl) phosphite, diasteryl pentaerythritol diphosphite, and bis(2,6-di-t-butyl-4-methylphenyl) pentaerythritol diphosphite. These antioxidants can be used individually or in combination.

[0061] In the resin composition according to the embodiment of the present invention, for example, polystyrene, polyethylene, polypropylene, ethylene-propylene copolymer, ethylene-butene copolymer, and ethylene-vinyl acetate copolymer can be used as the reinforcing resin. In addition to these, for example, thermoplastic polyester resins, polyamide resins, and polyphenylene ether resins with relatively low molecular weights can also be used.

[0062] Furthermore, in the resin composition according to the embodiment of the present invention, other elastomers, such as natural rubber, synthetic polyisoprene rubber, liquid polyisoprene rubber and its hydrogenated products, polybutadiene rubber, liquid polybutadiene rubber and its hydrogenated products, styrene-butadiene rubber, chloroprene rubber, ethylene-propylene rubber, acrylic rubber, polyisopreneisobutylene rubber, acrylonitrile-butadiene rubber, or styrene-based elastomers such as polystyrene-polyisoprene-polystyrene or polystyrene-polybutadiene-polystyrene, or hydrogenated styrene-based elastomers thereof, may be mixed and used, to the extent that the spirit of the present invention is not impaired.

[0063] In the resin composition according to the embodiment of the present invention, inorganic fillers may be added to the extent that their properties are not impaired. Specific examples of such inorganic fillers include, for example, talc, calcium carbonate, silica, glass fiber, mica, kaolin, and titanium dioxide.

[0064] The resin composition according to the embodiment of the present invention is preferably free of surfactants from the viewpoint of environmental considerations, but may further contain surfactants within a certain range. In this case, the amount of surfactant is preferably more than 0 ppm by mass and 5,000 ppm by mass or less, more preferably 10 ppm by mass and 4,000 ppm by mass or less, and even more preferably 50 ppm by mass and 3,500 ppm by mass or less, relative to the mass of the resin composition.

[0065] [Physical Properties of the Resin Composition] <Melting Viscosity at 180°C> The melting viscosity of the resin composition according to this embodiment at 180°C is preferably less than 50,000 mPa·s, more preferably 1,000 mPa·s or more and less than 50,000 mPa·s, even more preferably 1,500 mPa·s or more and 48,000 mPa·s or less, and even more preferably 2,000 mPa·s or more and 45,000 mPa·s or less, from the viewpoint of improving processability and ease of application. There is no particular limit to the lower limit of the above melting viscosity, but the above range is preferred from the viewpoint of ease of handling, etc. The above melting viscosity can be set to the above range by adjusting the amount of plasticizer added, for example. The above melting viscosity of the resin composition refers to the viscosity measured at 180°C using a Brookfield viscometer (Type B viscometer). In this specification, the melting viscosity of the resin composition is measured in accordance with JIS K 6862:1984. Specifically, it can be measured by the method described in the examples.

[0066] <180° Peel Strength> The 180° peel strength of the above resin composition, measured in accordance with JIS Z 0237:2009 at a temperature of 23°C and a peeling speed of 300 mm / min, is preferably 8.0 N / 25 mm to 50.0 N / 25 mm, more preferably 9.0 N / 25 mm to 50.0 N / 25 mm, and even more preferably 10.0 N / 25 mm to 50.0 N / 25 mm, from the viewpoint of ensuring high adhesiveness. There is no particular upper limit, but the above range is preferred from the viewpoint of ease of manufacture, etc. The above 180° peel strength can be set to the above range, for example, by adjusting the amount of tackifying resin. The above 180° peel strength is measured in detail by the method described in the examples.

[0067] <Interfacial Fracture Temperature (SAFT)> The interfacial fracture temperature (SAFT) of the above resin composition, measured in accordance with ASTM D3654M:2019, is preferably 95°C or higher, more preferably 100°C or higher, and even more preferably 110°C or higher, from the viewpoint of ensuring sufficient heat resistance. If higher heat resistance is required, it is preferably 130°C or higher, more preferably 150°C or higher, even more preferably 180°C or higher, even more preferably 200°C or higher, even more preferably 205°C or higher, and particularly preferably above 205°C. The above interfacial fracture temperature (SAFT) is measured in accordance with ASTM D3654M:2019 from the temperature at which the weight falls under the conditions of an adhesive area of ​​25 mm x 25 mm, a weight of 500 g, a temperature range of 40 to 205°C, and a heating rate of 0.5°C / min, and is measured in detail by the method described in the examples.

[0068] <Loop Tack Characteristics> The above resin composition is applied to a polyethylene terephthalate film using a hot melt coating machine at a coating temperature of 160 to 180°C to produce an adhesive tape having an adhesive layer with a thickness of 45 to 200 μm. The adhesive layer is then made into a loop shape with a width of 10 mm and a length of 100 mm, with the adhesive layer facing outwards. A 25 mm wide polymethyl methacrylate (PMMA) plate is attached to a loop tack tester in a direction intersecting the loop, and the loop tack characteristics are evaluated by measuring the tack value (maximum value when peeled off) according to the method described in PSTC-16. The loop tack characteristics are preferably 4 to 50 N, more preferably 5 to 40 N, and even more preferably 5 to 20 N. If the loop tack value is within the above range, good tackiness is exhibited immediately after the adhesive tape is applied, the conformability is good, and it is easy to reapply.

[0069] <Breaking Strength and Elongation at Break> The breaking strength of the sheet (molded article) obtained by compression molding the above resin composition is preferably 3 to 30 MPa, and more preferably 5 to 20 MPa. The elongation at break of the sheet (molded article) obtained by compression molding the above resin composition is preferably 400 to 1,200%, and more preferably 600 to 1,000%. The above breaking strength and elongation at break are measured using an Instron universal tester in accordance with JIS K 6251:2017. For details, the measurements are performed by the method described in the examples.

[0070] [Method for Manufacturing the Resin Composition] Any conventional method can be used to manufacture the resin composition according to this embodiment. For example, it can be manufactured by melt-kneading or melt-mixing the necessary components mentioned above in a nitrogen gas atmosphere, usually in the range of 130°C to 230°C, using a general tank-type mixer, high-speed stirrer, closed-type kneader, internal mixer, or extruder such as a single-screw extruder or twin-screw extruder, if necessary. The resin composition according to this embodiment, obtained by mixing the above components, can be made into an appropriate form depending on its application and mode of use. For example, it can be used in block, granular, flake, pellet, rod, film, or sheet form for various adhesive applications and adhesive products.

[0071] Furthermore, the resin composition according to this embodiment can also be prepared as a solvent-type adhesive composition by dissolving the solid components in an aliphatic solvent such as heptane, isopentane, n-hexane, or cyclohexane, or an aromatic solvent such as benzene, xylene, toluene, or ethylbenzene, so that the solid content concentration is generally 5% to 70% by mass, depending on the application.

[0072] [Uses of the Resin Composition] The uses of the resin composition according to the embodiment of the present invention are not particularly limited, and it can be used as an adhesive composition for adhesive bonding of various materials, similar to conventional hot-melt adhesives and pressure-sensitive adhesives. For example, it can be used for adhesive bonding of plastic films and sheets such as polyethylene, polypropylene, and polyester, as well as paper, wood, textile products, metal foil, leather, etc. More specifically, the resin composition according to the embodiment of the present invention can be used for packaging such as making bags, sealing small boxes and cardboard boxes, picking up labels, and manufacturing aluminum foil cans; bookbinding; plywood manufacturing; woodworking; shoemaking, carpet backing, nonwoven fabric binders and other textile products; manufacturing various hygiene products including disposable diapers and sanitary napkins; adhesive tapes for packaging; electrical insulation tapes and films; adhesive tapes and sheets for surface protection of various articles; various adhesive films and sheets used in semiconductor wafer manufacturing processes; bundling and fixing of pipes, etc.; sealing materials for various building materials such as window frames and around car lamps and instrument panels; and adhesives for labels.

[0073] If the resin composition according to the embodiment of the present invention is a hot-melt adhesive, the hot-melt adhesive can be heated and melted using a conventional hot-melt adhesive applicator, applied to the adherend, and then the adherends can be bonded together (pressed together) and allowed to solidify to perform adhesion.

[0074] When the resin composition according to the embodiment of the present invention is a hot-melt type pressure-sensitive adhesive (or pressure-sensitive tack), the hot-melt type pressure-sensitive adhesive (or pressure-sensitive tack) can be heated and melted and applied to one or both sides of a substrate such as paper, cloth, plastic film or sheet, or metal foil to form a layer of pressure-sensitive adhesive (or pressure-sensitive tack) on the substrate to produce adhesive films, adhesive sheets, and other adhesive products. In this case, the thickness of the adhesive layer is preferably 5 to 500 μm, more preferably 10 to 400 μm, and even more preferably 20 to 300 μm.

[0075] Whether the resin composition according to the embodiment of the present invention is a hot-melt adhesive or a hot-melt pressure-sensitive adhesive (or pressure-sensitive tack), the resin composition according to the embodiment of the present invention can be easily melted by heating to 180°C or higher, for example, 180°C to 200°C, and can be smoothly used for bonding work and manufacturing of adhesive products such as adhesive films with good processability.

[0076] The present invention also provides a resin composition having the following configuration: [Configuration X1] A resin composition comprising a block copolymer (I), a block copolymer (II), and a tackifying resin (X), wherein the block copolymer (I) comprises a polymer block (A1) containing α-methylstyrene units and a polymer block (B1) containing conjugated diene compound units, and the polymer block (A1) and the polymer block (B1) are a triblock copolymer represented as A1-B1-A1, and the block copolymer (II) comprises a polymer block (A2) containing α-methylstyrene units and a polymer block (B2) containing conjugated diene compound units, and the polymer block (A2) and the polymer block (B2) are a diblock copolymer represented as A2-B2. The block copolymer (I) and the block copolymer (II) are contained in a mass ratio of (I):(II) = 96:4 to 80:20, preferably 95:5 to 80:20, more preferably 95:5 to 82:18, even more preferably 95:5 to 84:16, and even more preferably 95:5 to 85:15, wherein the block copolymer (I) and the block copolymer (II) are hydrogenated block copolymers with a hydrogenation rate of 50 mol% to 100 mol%, preferably 70 mol% to 100 mol%, more preferably 90 mol% to 99.5 mol%, even more preferably 95 mol% to 99.5 mol%, and particularly preferably 97 mol% to 99.5 mol%. A resin composition in which the total content of polymer block (A1) and polymer block (A2) in 100% by mass of the total of block copolymer (I) and block copolymer (II) is 5% by mass or more and 55% by mass or less, preferably 10% by mass or more and 55% by mass or less, more preferably 10% by mass or more and 50% by mass or less, even more preferably 15% by mass or more and 50% by mass or less, and even more preferably 20% by mass or more and 50% by mass or less.

[0077] [Configuration X2] A resin composition comprising a block copolymer (I), a block copolymer (II), and a tackifying resin (X), wherein the block copolymer (I) comprises a polymer block (A1) containing α-methylstyrene units and a polymer block (B1) containing conjugated diene compound units, and the polymer block (A1) and the polymer block (B1) are a triblock copolymer represented as A1-B1-A1, and the block copolymer (II) comprises a polymer block (A2) containing α-methylstyrene units and a polymer block (B2) containing conjugated diene compound units, and the polymer block (A2) and the polymer block (B2) are a diblock copolymer represented as A2-B2. The block copolymer (I) and the block copolymer (II) are contained in a mass ratio of (I):(II) = 96:4 to 80:20, preferably 95:5 to 80:20, more preferably 95:5 to 82:18, even more preferably 95:5 to 84:16, and even more preferably 95:5 to 85:15, wherein the block copolymer (I) and the block copolymer (II) are hydrogenated block copolymers with a hydrogenation rate of 50 mol% to 100 mol%, preferably 70 mol% to 100 mol%, more preferably 90 mol% to 99.5 mol%, even more preferably 95 mol% to 99.5 mol%, and particularly preferably 97 mol% to 99.5 mol%. A resin composition in which the content of the tackifying resin (X) is 10% by mass or more and 55% by mass or less, preferably 10% by mass or more and 50% by mass or less, more preferably 15% by mass or more and 50% by mass or less, and even more preferably 20% by mass or more and 50% by mass or less, based on 100% by mass of the resin composition.

[0078] [Configuration X3] A resin composition comprising a block copolymer (I), a block copolymer (II), and a tackifying resin (X), wherein the block copolymer (I) comprises a polymer block (A1) containing α-methylstyrene units and a polymer block (B1) containing conjugated diene compound units, and the polymer block (A1) and the polymer block (B1) are a triblock copolymer represented as A1-B1-A1, and the block copolymer (II) comprises a polymer block (A2) containing α-methylstyrene units and a polymer block (B2) containing conjugated diene compound units, and the polymer block (A2) and the polymer block (B2) are a diblock copolymer represented as A2-B2. A resin composition comprising the block copolymer (I) and the block copolymer (II) in a mass ratio of (I):(II) = 96:4 to 80:20, preferably 95:5 to 80:20, more preferably 95:5 to 82:18, even more preferably 95:5 to 84:16, and even more preferably 95:5 to 85:15, wherein the block copolymer (I) and the block copolymer (II) are hydrogenated block copolymers with a hydrogenation rate of 50 mol% to 100 mol%, preferably 70 mol% to 100 mol%, more preferably 90 mol% to 99.5 mol%, even more preferably 95 mol% to 99.5 mol%, and particularly preferably 97 mol% to 99.5 mol%, and at least one conjugated diene compound unit selected from the group consisting of the conjugated diene compound units of the polymer block (B1) and the conjugated diene compound units of the polymer block (B2) is a structural unit derived from butadiene. [Configuration X4] A resin composition according to any one of X1 to X3, further comprising a plasticizer (Y). [Configuration X5] A resin composition according to any one of X1 to X4, which either does not contain a surfactant or further comprises a surfactant, wherein the content of the surfactant is greater than 0 ppm by mass and 5,000 ppm by mass or less, preferably 10 ppm by mass or more and 4,000 ppm by mass or less, and more preferably 50 ppm by mass or more and 3,500 ppm by mass or less, based on 100% by mass of the resin composition.

[0079] The present invention will be described in more detail below with reference to examples, but the present invention is not limited to these examples. The materials used in the following examples and comparative examples are as follows.

[0080] <Block Copolymers> ・Block copolymer (I)-1 and block copolymer (II)-1 from Production Example 1 described later ・Block copolymer (I)-2 and block copolymer (II)-2 from Production Example 2 described later ・Block copolymer (I)-3 and block copolymer (II)-3 from Production Example 3 described later ・Block copolymer (I)-4 and block copolymer (II)-4 from Production Example 4 described later ・Block copolymer (I)-5 and block copolymer (II)-5 from Production Example 5 described later ・Block copolymer (I)-6 from Production Example 6 described later ・Block copolymer (I)-7 and block copolymer (II)-7 from Production Example 7 described later ・Quintac 3421: Styrene-isoprene-styrene block copolymer manufactured by Nippon Zeon Co., Ltd.

[0081] <Tackifying Resins (X)> ・ARKON P90: Manufactured by Arakawa Chemical Industries, Ltd., hydrogenated petroleum resin, softening point 90±5℃ ・ARKON P100: Manufactured by Arakawa Chemical Industries, Ltd., hydrogenated petroleum resin, softening point 100±5℃ ・ARKON P125: Manufactured by Arakawa Chemical Industries, Ltd., hydrogenated petroleum resin, softening point 125±5℃ ・ARKON M135: Manufactured by Arakawa Chemical Industries, Ltd., partially hydrogenated petroleum resin, softening point 135±5℃ ・PINECRYSTAL KE-100: Manufactured by Arakawa Chemical Industries, Ltd., rosin ester resin, softening point 100±5℃ ・I-MARV P-100: Manufactured by Idemitsu Kosan Co., Ltd., hydrogenated petroleum resin, softening point 100±5℃ ・I-MARV P-125: Manufactured by Idemitsu Kosan Co., Ltd., hydrogenated petroleum resin, softening point 125±5℃

[0082] ・T-REZ HA085: Manufactured by ENEOS Corporation, Hydrogenated Petroleum Resin (DCPD), Softening point 85℃±5℃ ・T-REZ RB100: Manufactured by ENEOS Corporation, Aliphatic Hydrocarbon Resin (C5), Softening point 100℃±5℃ ・YS POLYSTER TH130: Manufactured by Yasuhara Chemical Co., Ltd., Terpene Phenolic Resin, Softening point 130±5℃ ・YS RESIN PX1250: Manufactured by Yasuhara Chemical Co., Ltd., Hydrogenated Terpene Resin, Softening point 125±5℃ ・YS RESIN PX1150: Manufactured by Yasuhara Chemical Co., Ltd., Hydrogenated Terpene Resin, Softening point 115±5℃ ・CLEARON P150: Manufactured by Yasuhara Chemical Co., Ltd., Hydrogenated Terpene Resin, Softening point 152℃±5℃・CLEARON M115: Manufactured by Yasuhara Chemical Co., Ltd., aromatic modified hydrogenated terpene resin, softening point 115℃±5℃ ・YS RESIN TO105: Manufactured by Yasuhara Chemical Co., Ltd., aromatic modified terpene resin, softening point 105±5℃

[0083] <Plasticizer (Y)> ・PW-90: Manufactured by Idemitsu Kosan Co., Ltd., paraffin-based process oil, kinematic viscosity (40°C): 90 mm ２ / s <Surfactants> ・Emulgen 409PV: Manufactured by Kao Corporation, polyoxyethylene oleyl ether <Antioxidants> ・ADEKA Stab AO-60: Manufactured by ADEKA Corporation, melting point 110-130°C, molecular weight 1,178

[0084] <Commercially available double-sided tapes> ・3M 467MP: 3M Corporation, acrylic double-sided tape ・3M 93015LE: 3M Corporation, acrylic double-sided tape ・No. 5000NS: Nitto Denko Corporation, acrylic double-sided tape ・No. 510: Nitto Denko Corporation, acrylic double-sided tape ・No. 512: Nitto Denko Corporation, acrylic double-sided tape ・VR-5300: Nitto Denko Corporation, rubber double-sided tape

[0085] [Measurement and Evaluation Methods] The details of the measurement methods for each physical property of the polymers obtained in each of the following manufacturing examples, and the measurement methods for each physical property of the resin compositions obtained in each of the following examples and comparative examples, as well as the evaluation methods for each evaluation item, are as follows.

[0086] <Measurement of Weight-Average Molecular Weight and Molecular Weight Distribution> The following items were measured by GPC (gel permeation chromatography). Specifically, the weight-average molecular weight (Mw) and molecular weight distribution (Mw / Mn) for each component were determined by GPC using standard polystyrene equivalent molecular weight. ・Weight-average molecular weight (Mw) of polymer block (A1) and polymer block (A2) ・Weight-average molecular weight (Mw) of block copolymer (I) and block copolymer (II) ・Molecular weight distribution (Mw / Mn) of block copolymer (I) and block copolymer (II) The weight-average molecular weight of each polymer block contained in each block copolymer was determined by measuring the sampled liquid each time polymerization of each polymer block was completed during the manufacturing process. The measurement equipment and conditions are as follows. • Equipment: Tosoh Corporation GPC system "HLC-8320GPC" • Separation column: Tosoh Corporation column "TSKgelSuperHZ4000" • Eluent: Tetrahydrofuran • Eluent flow rate: 0.7 mL / min • Sample concentration: 5 mg / 10 mL • Column temperature: 40°C

[0087] <Method for measuring hydrogenation rate> The hydrogenation rates of block copolymer (I) and block copolymer (II) were calculated by the following method. Unhydrogenated block copolymer and hydrogenated block copolymer were respectively dissolved in deuterated chloroform (CDCl). ３ Dissolve in ) １ ¹H-NMR measurements were performed [instrument: "AVANCE III 400 NanoBay" (Bruker), measurement temperature: 30°C]. The hydrogenation rate of the hydrogenated block copolymer was calculated from the peaks derived from styrene appearing at 6.5–7.5 ppm and the proton peaks of the carbon-carbon double bond (peaks derived from the carbon-carbon double bond) appearing at 4.5–6.0 ppm in the obtained spectrum using the following formula: Hydrogenation rate (mol%) = {1 - (Ratio of peak area derived from carbon-carbon double bond to peak area derived from styrene in the hydrogenated block copolymer) / (Ratio of peak area derived from carbon-carbon double bond to peak area derived from styrene in the unhydrogenated block copolymer)} × 100

[0088] <Amount of vinyl bond> Block copolymer before hydrogenation in deuterated chloroform (CDCl ３ (dissolve in) １ ¹H-NMR measurements were performed [instrument: "AVANCE III 400 NanoBay" (Bruker), measurement temperature: 30°C]. The amount of vinyl bonding was calculated from the ratio of the peak area corresponding to the 1,2-bonding units in the butadiene structural units to the total peak area of ​​the structural units derived from butadiene. The amount of vinyl bonding was calculated from the ratio of the peak areas corresponding to the 3,4-bonding units and 1,2-bonding units in the isoprene structural units to the total peak area of ​​the structural units derived from isoprene.

[0089] <Melting Viscosity> The melting viscosity of the resin compositions prepared in the examples and comparative examples at 140°C, 160°C, 180°C, and 200°C was measured in accordance with JIS K 6862-1984 using a Brookfield viscometer (manufactured by BROOKFIELD ENGINEERING LABS. INC.).

[0090] <Coating film thickness> The thickness of the coating film of the resin compositions prepared in the examples and comparative examples was measured using a digital thickness gauge (product name SMD-565J-L, manufactured by TECLOOK).

[0091] <Peel Test> The adhesive tapes prepared in the examples and comparative examples were cut to a width of 25 mm. These were then attached to a stainless steel plate (product name SUS304, thickness 1 mm, manufactured by ACC Co., Ltd.) as the substrate, with the adhesive side in contact with the stainless steel plate. After that, a 2 kg rubber roller was used to roll the tape at a speed of 10 mm / min, and then it was left to stand for 24 hours in an atmosphere of 23 ± 1 °C and 50 ± 5% humidity. Subsequently, a 180° peel test was performed in accordance with JIS Z 0237:2009 under conditions of a temperature of 23 °C and a peel speed of 300 mm / min, and the 180° peel strength was measured. In addition, the presence or absence of adhesive residue on the substrate after peeling and the failure mode if adhesive residue was present were confirmed. When the adhesive layer peeled off at the interface with the substrate (i.e., there was no adhesive residue on the substrate), it was evaluated as "AF", and when failure occurred inside the adhesive layer, it was evaluated as "CF". Similar measurements and evaluations were performed using a high-density polyethylene (HDPE) plate as the substrate.

[0092] <Loop Tack Characteristics> An adhesive tape having an adhesive layer prepared by the method described below was formed into a loop 25 mm wide x 100 mm long with the adhesive layer facing outwards at 23°C in a 50% RH atmosphere. A 25 mm wide polymethyl methacrylate (PMMA) plate (Delaglass A999, manufactured by Asahi Kasei Technoplus Corporation) was attached to a loop tack tester (Chem Instruments "LT-1000") in a direction intersecting the loop, and the tack value (maximum value when peeled off) was measured according to the method described in PSTC-16.

[0093] <Interfacial Fracture Temperature (SAFT)> For the adhesive tapes prepared in the examples and comparative examples, the interfacial fracture temperature (SAFT) was defined as the temperature at which the weight fell under the following conditions: adhesive area of ​​25 mm x 25 mm, weight of 500 g, temperature range of 40 to 205 °C, and heating rate of 0.5 °C / min, in accordance with ASTM D3654M:2019.

[0094] <Creep Test> The high-temperature retention capacity of the resin compositions of the examples and comparative examples was evaluated by conducting creep tests in accordance with JIS Z-0237:2022 using the adhesive tapes prepared in the examples and comparative examples. The thickness of the adhesive layer was as shown in Table 1. The adhesive tape was cut to a length of 25 mm x width of 25 mm and attached to a stainless steel (SUS304) plate, which was the adherend. A load of 1 kg was suspended at an ambient temperature of 70°C or 80°C, and the fall time was measured to evaluate the high-temperature retention capacity of each resin composition. If the tape did not fall after 10,000 minutes at an ambient temperature of 70°C, the displacement distance of the adhesive tape after 10,000 minutes was measured. If the tape did not fall after 240 minutes at an ambient temperature of 80°C, the displacement distance of the adhesive tape after 240 minutes was measured. If the tape did not fall, a smaller displacement distance of the adhesive tape after measurement indicated better high-temperature retention capacity. Similar tests were conducted at an ambient temperature of 70°C using polymethyl methacrylate (PMMA) plates and polypropylene (PP) plates as substrates.

[0095] <Compatibility> Compatibility was evaluated by visually checking the transparency of the resin compositions prepared in the examples and comparative examples. A rating of "G" was given when the resin composition was transparent and the area behind it could be seen, and a rating of "NG" was given when the resin composition was cloudy and the area behind it could not be seen.

[0096] [Production Example 1] Production of Block Copolymer Mixture 1 4.58 kg of α-methylstyrene, 7.42 kg of cyclohexane, and 0.091 kg of tetrahydrofuran were charged into a nitrogen-purged, pressure-resistant vessel with a stirring device. 0.4232 kg of sec-butyllithium (10.5% by mass cyclohexane solution) was added to this mixture, and polymerization was carried out at -10°C for 3 hours to form poly-α-methylstyrene. The weight-average molecular weight (Mw) of the obtained poly-α-methylstyrene was 6,600, and the polymerization conversion rate was 89%. Next, 1.82 kg of 1,3-butadiene was added to this reaction mixture, and polymerization was carried out by stirring at -10°C for 30 minutes, after which 42.58 kg of cyclohexane was added. At this point, the polymerization conversion rate of α-methylstyrene was 89%, and the number-average molecular weight (GPC measurement, equivalent to standard polystyrene) of the formed polybutadiene block was 3,700. １ The amount of vinyl bond determined by 1H-NMR measurement was 81 mol%. Next, 9.38 kg of 1,3-butadiene was added to this reaction solution, and the polymerization reaction was carried out at 50°C for 2 hours. The weight-average molecular weight (Mw) of the resulting polybutadiene block copolymer was 29,800. １ The amount of vinyl binding determined from 1H-NMR measurement was 43 mol%.

[0097] Next, 0.0328 kg of dichlorodimethylsilane was added to this polymerization reaction solution and stirred at 50°C for 1 hour to obtain a mixture containing poly-α-methylstyrene-polybutadiene-poly-α-methylstyrene triblock copolymer and poly-α-methylstyrene-polybutadiene diblock copolymer. At this time, the weight ratio of poly-α-methylstyrene-polybutadiene-poly-α-methylstyrene triblock copolymer (weight-average molecular weight (Mw) = 78,500) and poly-α-methylstyrene-polybutadiene diblock copolymer (weight-average molecular weight (Mw) = 36,000), calculated from the area ratio of UV absorption in GPC, was 90% by mass for the triblock copolymer and 10% by mass for the diblock copolymer. １ ¹H-NMR analysis revealed that the total content of poly-α-methylstyrene blocks (polymer blocks (A1) and (A2)) in the poly-α-methylstyrene-polybutadiene-poly-α-methylstyrene triblock copolymer and poly-α-methylstyrene-polybutadiene diblock copolymer was 29% by mass, and the amount of vinyl bonding in the polybutadiene blocks (polymer blocks (B1) and (B2)) was 43 mol%. A Ziegler-type hydrogenation catalyst formed from nickel octoate and triethylaluminum was added to the polymerization reaction solution obtained above under a hydrogen atmosphere, and a hydrogenation reaction was carried out at a hydrogen pressure of 0.8 MPa and 80°C for 5 hours to obtain block copolymer mixture 1 containing hydrogenated poly-α-methylstyrene-polybutadiene-poly-α-methylstyrene triblock copolymer [hereinafter abbreviated as block copolymer (I)-1] and hydrogenated poly-α-methylstyrene-polybutadiene diblock copolymer [hereinafter abbreviated as block copolymer (II)-1].

[0098] From the area ratio of UV (254 nm) absorption in GPC of block copolymer mixture 1, it was found that block copolymer (I)-1 accounts for 90% by mass and block copolymer (II)-1 accounts for 10% by mass of the total 100% by mass of block copolymer mixture 1. Furthermore, from the GPC measurement results of block copolymer mixture 1, the peak-top molecular weight (Mt) of block copolymer (I)-1 was 81,000, the number-average molecular weight (Mn) was 78,000, the weight-average molecular weight (Mw) was 80,340, and the molecular weight distribution (Mw / Mn) was 1.03. Also, the weight-average molecular weight (Mn) of block copolymer (II)-1 was 35,900, the weight-average molecular weight (Mw) was 34,400, and the molecular weight distribution (Mw / Mn) was 1.1. １ ¹H-NMR measurements revealed that the hydrogenation rates of polymer block (B1) and polymer block (B2) were 98.0 mol%. In other words, the hydrogenation rates of block copolymer (I)-1 and block copolymer (II)-1 were 98.0 mol%.

[0099] [Production Example 2] Production of Block Copolymer Mixture 2 Block copolymer mixture 2 was produced using the same procedure as block copolymer mixture 1 in Production Example 1, except that the amount of dichloromethylsilane used was changed to 0.0346 kg. As shown in Table 1 below, in block copolymer mixture 2, the mass ratio [(I)-2] / [(II)-2] of block copolymer (I)-2, which is a triblock copolymer, and block copolymer (II)-2, which is a diblock copolymer, was 95 / 5. Other physical properties are as shown in Table 1.

[0100] [Production Example 3] Production of Block Copolymer Mixture 3 Block copolymer mixture 3 was produced using the same procedure as block copolymer mixture 1 in Production Example 1, except that the amount of dichloromethylsilane used was changed to 0.0310 kg. As shown in Table 1 below, in block copolymer mixture 3, the mass ratio [(I)-3] / [(II)-3] of block copolymer (I)-3, which is a triblock copolymer, and block copolymer (II)-3, which is a diblock copolymer, was 85 / 15. Other physical properties are as shown in Table 1.

[0101] [Production Example 4] Production of Block Copolymer Mixture 4 Block copolymer mixture 4 was produced using the same procedure as block copolymer mixture 1 in Production Example 1, except that the amount of dichloromethylsilane used was changed to 0.0273 kg. As shown in Table 1 below, in block copolymer mixture 4, the mass ratio [(I)-4] / [(II)-4] of block copolymer (I)-4, which is a triblock copolymer, and block copolymer (II)-4, which is a diblock copolymer, was 75 / 25. Other physical properties are as shown in Table 1.

[0102] [Production Example 5] Production of Block Copolymer Mixture 5 Block copolymer mixture 5 was produced using the same procedure as block copolymer mixture 1 in Production Example 1, except that the amount of dichloromethylsilane used was changed to 0.0218 kg. As shown in Table 1 below, in block copolymer mixture 5, the mass ratio [(I)-5] / [(II)-5] of block copolymer (I)-5, which is a triblock copolymer, and block copolymer (II)-5, which is a diblock copolymer, was 60 / 40. Other physical properties are as shown in Table 1.

[0103] [Production Example 6] Production of Block Copolymer (I)-6 A nitrogen-purged and dried pressure vessel was charged with 50.0 kg of cyclohexane as a solvent, 0.1028 kg of sec-butyllithium (10.5% by mass cyclohexane solution) as an anionic polymerization initiator, and 0.073 kg of tetrahydrofuran as a Lewis base. After raising the temperature to 50°C, 1.32 kg of styrene (1) was added and polymerization was carried out for 1 hour. A mixture of 6.18 kg of butadiene was added and polymerization was carried out for 2 hours. Further polymerization was carried out by adding 1.32 kg of styrene (2) for 1 hour to obtain a reaction solution containing polystyrene-polybutadiene-polystyrene triblock copolymer. To the above reaction solution, 5% by mass of palladium carbon (palladium loading: 5% by mass) was added to the block copolymer as a hydrogenation catalyst, and the reaction was carried out for 10 hours under conditions of hydrogen pressure of 2 MPa and 150°C. After cooling and pressure release, the hydrogenation catalyst was removed by filtration, the filtrate was concentrated, and further vacuum drying was performed to obtain hydrogenated polystyrene-polybutadiene-polystyrene triblock copolymer (SEBS) (block copolymer (I)-6).

[0104] [Production Example 7] Production of Block Copolymer Mixture 7 A nitrogen-purged and dried pressure vessel was charged with 50.0 kg of cyclohexane as a solvent and 0.0611 kg of sec-butyllithium (10.5% by mass cyclohexane solution) as an anionic polymerization initiator. After raising the temperature to 50°C, 0.81 kg of styrene (1) was added and polymerization was carried out for 1 hour. Subsequently, 10.87 kg of isoprene was added and polymerization was carried out for 2 hours. Further polymerization was carried out by adding 0.81 kg of styrene (2) for 1 hour to obtain a reaction solution containing polystyrene-polyisoprene-polystyrene triblock copolymer. To this reaction solution, 5% by mass of palladium carbon (palladium loading: 5% by mass) was added to the block copolymer as a hydrogenation catalyst, and the reaction was carried out for 10 hours under conditions of hydrogen pressure of 2 MPa and 150°C. After cooling and release of pressure, the palladium carbon was removed by filtration, the filtrate was concentrated, and further vacuum-dried to obtain a hydrogenated product of polystyrene-polyisoprene-polystyrene triblock copolymer (block copolymer (I)-7).

[0105] Furthermore, similar to block copolymer (I)-7, 50.0 kg of cyclohexane as the solvent and 0.4200 kg of sec-butyllithium (10.5% by mass cyclohexane solution) (44.1 g of sec-butyllithium) as an anionic polymerization initiator were charged into a nitrogen-purged and dried pressure vessel. After raising the temperature to 50°C, 2.83 kg of styrene (1) was added and polymerization was carried out for 1 hour, followed by the addition of 19.81 kg of isoprene and polymerization was carried out for 2 hours to obtain a reaction solution containing polystyrene-polyisoprene block copolymer. Hydrogenation was carried out in the same manner as for block copolymer (I)-7 to obtain a hydrogenated product of polystyrene-polyisoprene block copolymer (block copolymer (II)-7). The block copolymer (I)-7 and block copolymer (II)-7 obtained above were melt-kneaded using a Coperion twin-screw extruder "ZSK26MagaCopounder" (L / D=56) at a screw speed of 300 rpm and a kneading temperature of 200°C to obtain a block copolymer mixture 7.

[0106] The structure and measurement results of each physical property of the block copolymer mixtures obtained in Production Examples 1-5 and 7, and the block copolymer obtained in Production Example 6, are shown in Tables 1-1 and 1-2, along with the components used and their amounts.

[0107]

[0108]

[0109] [Examples 1, 1A, 1B, 2-27, Comparative Examples 1-22] The block copolymer mixture or block copolymer, tackifying resin or other resin obtained in Production Examples 1-7, along with plasticizers, surfactants, and antioxidants as needed, were placed in a kneader heated to 180°C in the formulations shown in Tables 2-1 to 4-2 (all by mass%) and melt-mixed for 1-3 hours to prepare a resin composition. Using a hot-melt coating machine, a coating film (adhesive layer) of the resin composition was formed on a polyethylene terephthalate film (thickness 50 μm) at a coating temperature of 160-180°C to produce an adhesive tape. The properties described above were measured and evaluated using the obtained adhesive tape.

[0110]

[0111]

[0112] As can be seen from Table 2-1, the resin compositions of Examples 1, 1A, 1B, and 2-7 had low melt viscosity at 180°C and good coatability. They also showed high high-temperature retention strength for SUS, PMMA, and PP, and high SAFT. Furthermore, they showed high peel strength for HDPE and SUS, and high loop tack characteristics for PMMA. The resin composition of Example 2, which had a lower amount of plasticizer than the resin composition of Example 1, had a slightly higher melt viscosity at 180°C, but its high-temperature retention strength was equivalent to that of the resin composition of Example 1. The resin composition of Example 3, which had a higher amount of surfactant than the resin composition of Example 1, showed a slightly larger amount of shear in the creep test, but its retention time at high temperatures was equivalent to that of Example 1. The resin compositions of Examples 1A and 1B are made of the same material as the resin composition of Example 1, but due to the greater thickness of the adhesive layer compared to Example 1, the 180° peel strength and loop tack values ​​were higher. In the 70°C creep test, the retention time was longer for all objects, and the adherends did not fall off within 10,000 hours.

[0113] On the other hand, in Comparative Examples 1 and 2, the resin compositions used block copolymer mixtures in which the mass ratio of block copolymer (I) to block copolymer (II) was outside the range of (I):(II) = 96:4 to 80:20 resulted in a significant decrease in creep test evaluation compared to the examples, and the SAFT value was also lower compared to the examples.

[0114] Furthermore, the creep test evaluations of the resin compositions of Comparative Examples 3 and 4 were significantly lower compared to the resin compositions of the Examples. In particular, the resin composition of Comparative Example 3 had an extremely high melt viscosity at 180°C and was unsuitable for hot-melt adhesives. Also, the resin composition of Comparative Example 6 had a lower SAFT than the resin composition of the Examples.

[0115] The resin composition of Comparative Example 5 used a block copolymer that does not have structural units derived from α-methylstyrene, resulting in a significantly lower creep test evaluation compared to the resin composition of the example, and a significantly reduced retention time for all substrates.

[0116] Comparative Examples 6 to 11, which used commercially available double-sided tape, showed significantly lower high-temperature retention strength against PMMA and PP compared to the resin composition of the Examples. In particular, the resin compositions of Comparative Examples 8, 10, and 11 showed significantly inferior high-temperature retention strength against SUS compared to the resin composition of the Examples. Furthermore, the resin composition of Comparative Example 6 had lower peel strength against HPDE compared to the resin composition of the Examples.

[0117]

[0118]

[0119]

[0120] From Tables 3-1, 3-2, and 4, it can be seen that the resin compositions of Examples 8 to 27 had good compatibility.

[0121] [Evaluation of Adhesion and Cutability to Polymethyl Methacrylate (PMMA)] The adhesion to PMMA of the adhesive tapes of Example 1 and Comparative Example 5 described above was confirmed using the following procedure. In addition, the cutability of the resin compositions used in Example 1 and Comparative Example 5 was evaluated using the following procedure. Furthermore, as Comparative Example 14, a commercially available rubber-based adhesive (JM6197 manufactured by Sekisui Fuller Co., Ltd.) was used, and its cutability was evaluated using the same procedure. The adhesion to PMMA of the adhesive tape prepared using the same procedure as in Example 1 was also confirmed using the same procedure.

[0122] <Adhesion to PMMA> Samples cut to a width of 15 mm were attached to a PMMA board (Delaglass A999, manufactured by Asahi Kasei Technoplus Corporation). Then, a 2 kg rubber roller was used to compact the sample at a speed of 10 mm / min. A 200 g weight was attached to one end of the sample, and it was left standing at a 90-degree angle for 60 minutes in an atmosphere of 23 ± 1 °C and 50 ± 5% humidity. The distance from the aforementioned end of the sample that had peeled off the PMMA board was measured. For Comparative Example 14, since it peeled off completely within 60 minutes under the same conditions, the time required for 10 cm of peeling was measured.

[0123] <Cutability> The resin compositions used in Example 1 and Comparative Example 5, and the adhesive used in Comparative Example 14, were each compressed and molded at 180°C and 10 MPa for 3 minutes to obtain sheets (molded bodies) (150 mm in length, 150 mm in width, and 2 mm in thickness). Test specimens were obtained by punching out dumbbell-shaped No. 3 test pieces in accordance with JIS K 6251:2017 using these test specimens. Breaking strength and elongation at break were measured using an Instron universal tester (Instron Japan Co., Ltd. "Instron 5566") under conditions of 23°C and a tensile speed of 300 mm / min in accordance with JIS K 6251:2017. Note that the higher the breaking strength, the better the cutability of the adhesive, and the lower the elongation at break, the better the cutability of the adhesive.

[0124] The measurement results for each of the above physical properties are shown in Table 5.

[0125]

[0126] As shown in Table 5, the resin composition of Example 1 exhibited high adhesion to PMMA. Furthermore, its molded article had good cutability. In contrast, the composition of Comparative Example 5, which used a block copolymer without structural units derived from α-methylstyrene, had good cutability in its molded article, but its adhesion to PMMA was significantly inferior to that of Example 1. Furthermore, the adhesive of Comparative Example 14 had inferior adhesion to PMMA compared to Example 1, resulting in significant peeling in a short time. Moreover, its molded article had lower breaking strength and greater elongation at break compared to Example 1, and was inferior in cutability.

[0127] According to the present invention, a resin composition is obtained that has high meltability and good coatability, while also having a high interfacial fracture temperature and exhibiting high high-temperature retention for adherends of various materials. For this reason, the above resin composition is suitably used as an adhesive composition, particularly a hot-melt adhesive composition. This application is based on Japanese Patent Application No. 2024-184466 filed on October 18, 2024, and Japanese Patent Application No. 2025-056650 filed on March 28, 2025, both of which are incorporated by reference.

Claims

1. A resin composition comprising a block copolymer (I), a block copolymer (II), and a tackifying resin (X), wherein the block copolymer (I) comprises a polymer block (A1) containing α-methylstyrene units and a polymer block (B1) containing conjugated diene compound units, and the polymer block (A1) and the polymer block (B1) are a triblock copolymer represented as A1-B1-A1; the block copolymer (II) comprises a polymer block (A2) containing α-methylstyrene units and a polymer block (B2) containing conjugated diene compound units, and the polymer block (A2) and the polymer block (B2) are a diblock copolymer represented as A2-B2; the block copolymer (I) and the block copolymer (II) are contained in a mass ratio of (I):(II) = 96:4 to 80:20; and the block copolymer (I) and the block copolymer (II) are hydrogenated block copolymers with a hydrogenation rate of 50 mol% or more and 100 mol% or less.

2. The resin composition according to claim 1, wherein the total content of polymer block (A1) and polymer block (A2) in 100% by mass of the total of block copolymer (I) and block copolymer (II) is 5% by mass or more and 55% by mass or less.

3. The resin composition according to claim 1 or 2, wherein the melt viscosity at 180°C is less than 50,000 mPa·s.

4. The resin composition according to any one of claims 1 to 3, wherein it does not contain a surfactant, or further contains a surfactant, and the amount of the surfactant is greater than 0 ppm by mass and 5,000 ppm by mass or less, based on 100% by mass of the resin composition.

5. The resin composition according to any one of claims 1 to 4, wherein the content of the tackifying resin (X) is 10% by mass or more and 55% by mass or less based on 100% by mass of the resin composition.

6. The resin composition according to any one of claims 1 to 5, wherein at least one conjugated diene compound unit selected from the group consisting of the conjugated diene compound units of polymer block (B1) and the conjugated diene compound units of polymer block (B2) is a structural unit derived from butadiene.

7. The resin composition according to any one of claims 1 to 6, further comprising a plasticizer (Y).

8. A resin composition according to any one of claims 1 to 7, which is an adhesive composition.

9. An adhesive tape using the adhesive composition described in claim 8.

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