Grease composition

Abstract

Provided are: a grease composition comprising components (I) to (III), the component (I) being a base oil, the component (II) being a thickening agent, the component (III) being a block copolymer containing a polymer block (A) and a polymer block (B) or a hydrogenated product thereof, wherein the polymer block (A) contains a structure unit (S) derived from an aromatic vinyl compound as a main structure unit, and wherein the polymer block (B) contains a structure unit (T) derived from a conjugated diene compound as a main structure unit and contains a structure unit (X) represented by formula (X) (each symbol in formula (X) is defined in the description); a method for producing the grease composition; a slide member having the grease composition; and a copolymer for a grease composition.

Description

Grease composition

[0001] The present invention relates to a grease composition and a method for producing the same, a sliding member having the grease composition, and a copolymer for a grease composition.

[0002] Grease compositions are used in sliding components of automobiles and various industrial machines to reduce friction on their sliding surfaces. Grease compositions are particularly suitable for use in sliding locations where lubrication with lubricating oil is difficult. In recent years, various machines have become more electronic and their components have become smaller and lighter. For example, in automobiles, the emergence of new automobiles such as hybrid vehicles and electric vehicles has led to the advancement of smaller and lighter automobile components. At the same time, there is a demand for further reduction in the operating noise of automobile components in order to improve quietness in spaces such as the automobile cab. While there has traditionally been a demand for reduction in engine-derived noise, automobiles with the aforementioned new drive modes are increasingly demanding reductions in noise caused by the sliding and vibration of sliding components, such as motor components and various gears connected to the motor. Similarly, there is a demand for further reduction in the operating noise caused by the sliding components inside various industrial machines. For example, Patent Document 1 discloses a grease composition containing a base oil containing polyalphaolefin (PAO), a thickener containing lithium soap, a styrene-based block copolymer having a glass transition point (Tg) of less than −20° C., and a styrene-based block copolymer having a glass transition point (Tg) of −20° C. or higher.

[0003] International Publication No. 2019 / 017227

[0004] As described above, in recent years, development of novel grease compositions capable of reducing noise and vibration has been underway as grease compositions to be used in sliding members used in various machines. As a result of investigations by the present inventors, it has been confirmed that a novel grease composition capable of reducing noise and vibration can be obtained.

[0005] Therefore, an object of the present invention is to provide a novel grease composition that can reduce noise and vibration.

[0006] The present invention includes the following inventions: [1] A grease composition containing the following components (I) to (III): (I) a base oil; (II) a thickener; and (III) a block copolymer or a hydrogenated product thereof, comprising a polymer block (A) and a polymer block (B), wherein the polymer block (A) contains a structural unit (S) derived from an aromatic vinyl compound as a main structural unit, and the polymer block (B) contains a structural unit (T) derived from a conjugated diene compound as a main structural unit and also contains a structural unit (X) represented by the following formula (X): (In formula (X), R １ ~R ３ are each independently a hydrogen atom or a hydrocarbon group having 1 to 11 carbon atoms. When the polymer block (B) contains two or more structural units (X), the plurality of R １ may be the same or different, and there are multiple R ２ may be the same or different, and there are multiple R ３ may be the same or different. [2] The polymer block (B) has, as the structural unit (X), R １ ~R ３ [3] The grease composition according to [2], wherein the hydrocarbon group having 1 to 11 carbon atoms in the structural unit (Xc) is a methyl group. [4] The grease composition according to [1], wherein the structural unit (X) is a methyl group represented by the formula (X), R １ ~R ３The grease composition according to any one of [1] to [3], wherein the polymer block (B) contains a structural unit (Xh) in which all of the structural units (X) are hydrogen atoms. [5] The grease composition according to any one of [1] to [4], wherein the content of the structural unit (X) in the polymer block (B) is 0.5 mol % or more, based on 100 mol % of the total amount of structural units constituting the polymer block (B). [6] The grease composition according to [2] or [3], wherein the content of the structural unit (Xc) in the polymer block (B) is 0.5 mol % or more, based on 100 mol % of the total amount of structural units constituting the polymer block (B). [7] The grease composition according to any one of [1] to [6], wherein the component (III) is a hydrogenated product of a block copolymer having an iodine value of 0 to 200 g / 100 g. [8] The grease composition according to any one of [1] to [7], wherein the amount of vinyl bonds in the polymer block (B) is 55 to 99 mol %. [9] The grease composition according to any one of [1] to [8], wherein the component (III) has a temperature range in which tan δ is 1.0 or more as measured in accordance with JIS K7244-10:2005 under conditions of a strain of 0.1%, a frequency of 1 Hz, a measurement temperature of -70 to +100°C, and a heating rate of 3°C / min, and the maximum width of the temperature range is 12°C or more.

[10] The grease composition according to any one of [1] to [9], wherein the content of the structural unit (S) in the polymer block (A) is 70 mol% or more based on 100 mol% of the total amount of structural units constituting the polymer block (A).

[11] The grease composition according to any one of [1] to

[10] , wherein the content of the structural unit (T) in the polymer block (B) is 30 mol% or more based on 100 mol% of the total amount of structural units constituting the polymer block (B).

[12] The grease composition according to any one of [1] to

[11] above, wherein the content of the polymer block (A) in the component (III) is 1 to 50 mass% based on 100 mass% of the total amount of structural units constituting the component (III).

[13] The grease composition according to any one of [1] to

[12] above, wherein the total content of the polymer block (A) and the polymer block (B) in the component (III) is 90 to 100 mass% based on 100 mass% of the total amount of structural units constituting the component (III).

[14] The grease composition according to any one of [1] to

[13] , wherein the component (III) has at least one functional group selected from an alkoxysilyl group, a carboxy group, an amino group, a hydroxy group, an epoxy group, and a group derived from an acid anhydride.

[15] The grease composition according to

[14] , wherein the content of the functional group in the component (III) is 0.1 to 5.0 phr.

[16] The grease composition according to any one of [1] to

[15] , wherein the aromatic vinyl compound contains a styrene-based compound.

[17] The grease composition according to

[16] , wherein the content of structural units derived from a styrene-based compound in the component (III) is 1 to 25 mass% relative to the total amount (100 mass%) of the structural units constituting the component (III).

[18] The grease composition according to any one of [1] to

[17] , wherein the conjugated diene compound contains isoprene.

[19] The grease composition according to any one of [1] to

[18] above, wherein the content of the component (III) is 0.5 to 20 mass% relative to 100 mass% of the total amount of the grease composition.

[20] The grease composition according to any one of [1] to

[19] above, which is a noise-deadening grease composition.

[21] A sliding member comprising the grease composition according to any one of [1] to

[20] above.

[22] The sliding member according to

[21] above, which contains at least one selected from metals and resins.

[23] The sliding member according to

[21] or

[22] above, which is an automobile part or an industrial machinery part.

[24] The sliding member according to any one of

[21] to

[23] above, which is a motor part.

[25] A method for producing a grease composition according to any one of the above [1] to

[19] , comprising mixing a copolymer composition containing at least the component (I) and the component (III) with a thickener composition containing the component (I) and the component (II) to prepare a grease composition containing the components (I) to (III).

[26] A copolymer for a grease composition, which is a block copolymer or a hydrogenated product thereof, comprising a polymer block (A) and a polymer block (B), wherein the polymer block (A) comprises a structural unit (S) derived from an aromatic vinyl compound as a main structural unit, and the polymer block (B) comprises a structural unit (T) derived from a conjugated diene compound as a main structural unit, and also comprises a structural unit (X) represented by the following formula (X): (In formula (X), R １ ~R ３ are each independently a hydrogen atom or a hydrocarbon group having 1 to 11 carbon atoms. When the polymer block (B) contains two or more structural units (X), the plurality of R １ may be the same or different, and there are multiple R ２ may be the same or different, and there are multiple R ３ may be the same or different.)

[0007] According to the present invention, a novel grease composition capable of reducing noise and vibration can be provided.

[0008] The following describes an embodiment of the present invention. However, the embodiment described below is merely an example for embodying the technical concept of the present invention, and the present invention is not limited to the following description. The present invention also includes embodiments in which the details described herein are arbitrarily selected or arbitrarily combined. In this specification, preferred specifications can be selected arbitrarily, and combinations of preferred specifications are considered more preferable. Unless otherwise specified, a numerical range described as "XX to YY" means "XX or more and YY or less." For example, simply describing a numerical range as "10 to 90" indicates a range of 10 to 90. In this specification, lower and upper limits described in stages for numerical ranges (e.g., the content of each component, values ​​calculated from each component and each physical property, and each manufacturing condition) can be independently combined. For example, a description of "preferably 10 to 90, more preferably 30 to 60" for the same item can be combined with a "preferable lower limit (10)" and a "more preferable upper limit (60)" to form "10 to 60." Furthermore, for a numerical range, for example, based on the description "preferably 10 to 90, more preferably 30 to 60," the upper limit can be specified without a specific upper limit, and only the lower limit can be specified as "10 or more" or "30 or more." Similarly, the lower limit can be specified as "90 or less" or "60 or less" without a specific lower limit. As above, for example, from the description "preferably 10 or more, more preferably 30 or more" and the description "preferably 90 or less, more preferably 60 or less" for the same item, the "preferable lower limit (10)" and the "more preferable upper limit (60)" can be combined to form "10 or more to 60." Similarly, the lower limit can be specified as "10 or more" or "30 or more." Similarly, the upper limit can be specified as "90 or less" or "60 or less." The same applies when the terms "more than" and "less than" in the above description are written as "more than" and "less than," respectively. That is, for example, based on the description "preferably more than 10 and less than 90, more preferably 30 or more and 60 or less," the upper and lower limits can be combined to form "more than 10 and 60 or less" or "30 or more and less than 90."Furthermore, in this specification, unless otherwise specified, the expression "reduction of noise or vibration" more specifically refers to the effect achieved by the grease composition of one embodiment of the present invention. Similarly, in this specification, unless otherwise specified, the expression "low-temperature characteristics" refers to one or more characteristics selected from the appearance and starting torque of the grease composition of one embodiment of the present invention in a low-temperature environment.

[0009] [Grease Composition] A grease composition according to one embodiment of the present invention contains the following components (I) to (III): (I) a base oil; (II) a thickener; and (III) a block copolymer or a hydrogenated product thereof, comprising a polymer block (A) and a polymer block (B), wherein the polymer block (A) contains, as a main structural unit, a structural unit (S) derived from an aromatic vinyl compound, and the polymer block (B) contains, as a main structural unit, a structural unit (T) derived from a conjugated diene compound, and also contains a structural unit (X) represented by the following formula (X): (In formula (X), R １ ~R ３ are each independently a hydrogen atom or a hydrocarbon group having 1 to 11 carbon atoms. When the polymer block (B) contains two or more structural units (X), the plurality of R １ may be the same or different, and there are multiple R ２ may be the same or different, and there are multiple R ３ may be the same or different.) Each component of the grease composition according to one embodiment of the present invention will now be described.

[0010] <Component (I): Base Oil> The base oil of component (I) (hereinafter also referred to as "component (I)") is preferably at least one selected from the group consisting of mineral oils and synthetic oils. Examples of mineral oils include paraffinic mineral oils and naphthenic mineral oils obtained by conventional refining methods such as solvent refining and hydrogenation refining, as well as waxes (gas-to-liquid wax) produced by the Fischer-Tropsch process and the like, and mineral oils produced by isomerizing wax. The synthetic oil is preferably at least one selected from the group consisting of hydrocarbon synthetic oils and ether synthetic oils. The hydrocarbon synthetic oil is preferably at least one selected from the group consisting of α-olefin oligomers such as polybutene, polyisobutylene, 1-octene oligomer, 1-decene oligomer, and ethylene-propylene copolymer, or hydrogenated products thereof, alkylbenzene, and alkylnaphthalene. The ether synthetic oil is preferably at least one selected from the group consisting of polyoxyalkylene glycols and polyphenyl ethers.

[0011] Component (I) may be a single oil selected from the mineral oils and synthetic oils, or a mixture of two or more mineral oils, two or more synthetic oils, or one or more mineral oils and one or more synthetic oils. In one embodiment of the present invention, component (I) is preferably a base oil classified into Groups I, II, III, IV, and V of the American Petroleum Institute (API) base oil classification, with Groups I, II, and III being preferred due to their easy availability, and Groups II and III being more preferred due to their low sulfur content and high saturated content. It is further preferred that the Group II and III base oils are mineral oils, and even more preferred that they are mineral oils. In another embodiment of the present invention, component (I) may also be a poly-α-olefin (PAO) classified into Group IV.

[0012] The kinematic viscosity of component (I) at 40°C can be appropriately selected depending on the intended use of the resulting grease composition. For example, in one embodiment of the present invention, the kinematic viscosity of component (I) at 40°C is preferably 5 to 1,000 mm ２ / s, more preferably 10 to 500 mm ２ / s, more preferably 20 to 200 mm ２ / s, and even more preferably 25 to 50 mm ２ The kinematic viscosity is a value measured at 40°C in accordance with JIS K2283:2000.

[0013] The content of component (I) in the grease composition is preferably 70 to 98 mass%, more preferably 75 to 97 mass%, even more preferably 80 to 96 mass%, still more preferably 85 to 95 mass%, and even more preferably 87 to 93 mass%, relative to 100 mass% of the total amount of the grease composition.

[0014] <Component (II): Thickener> The thickener of component (II) (hereinafter also referred to as "component (II)") is not particularly limited as long as it achieves the effects of the present invention, but for example, one or more types selected from soap-based thickeners and non-soap-based thickeners are preferred.

[0015] The soap-based thickener is preferably a metal soap containing a metal salt, and the metal salt is preferably at least one selected from the group consisting of lithium, calcium, aluminum, sodium, potassium, barium, and strontium. More specifically, the metal soap is preferably a simple soap or a complex soap. The simple soap is preferably at least one selected from the group consisting of lithium soap, calcium soap, aluminum soap, and sodium soap. The complex soap is preferably at least one selected from the group consisting of lithium complex soap, calcium complex soap, calcium sulfonate complex soap, and aluminum complex soap. In one aspect of the present invention, the soap-based thickener is preferably a lithium soap-based thickener that is at least one selected from the group consisting of lithium soap and lithium complex soap; or a calcium soap-based thickener that is at least one selected from the group consisting of calcium soap, calcium complex soap, and calcium sulfonate complex soap; with the lithium soap-based thickener being more preferred.

[0016] The soap-based thickener can be obtained, for example, by saponifying one or more selected from carboxylic acids and carboxylic acid esters with a metal hydroxide. For example, the soap-based thickener can be produced by blending one or more selected from carboxylic acids and carboxylic acid esters with a metal hydroxide into a base oil (component (I)) and saponifying the mixture in the base oil. Alternatively, an aqueous solution of a metal hydroxide can be added to a base oil containing one or more selected from carboxylic acids and carboxylic acid esters, and heated as necessary to produce the soap-based thickener through saponification in the base oil. After adding the aqueous solution of a metal hydroxide and carrying out the saponification reaction, unnecessary water can be removed by evaporation or the like. Alternatively, a pressurized saponification method can be used in which pressure is applied during the saponification reaction.

[0017] The carboxylic acid is preferably at least one selected from crude fatty acids, monocarboxylic acids, monohydroxycarboxylic acids, dibasic acids, and aromatic carboxylic acids. The crude fatty acids are obtained by hydrolyzing fats and oils and removing glycerin. The monocarboxylic acid is preferably stearic acid. The monohydroxycarboxylic acid is preferably 12-hydroxystearic acid. The dibasic acid is preferably azelaic acid. The aromatic carboxylic acid is preferably at least one selected from terephthalic acid, salicylic acid, and benzoic acid. The metal hydroxide is preferably one or more selected from the group consisting of hydroxides of lithium, calcium, aluminum, sodium, potassium, barium, and strontium. More preferably, one or more selected from the group consisting of lithium hydroxide, calcium hydroxide, and aluminum hydroxide, even more preferably one or more selected from lithium hydroxide and calcium hydroxide, and even more preferably lithium hydroxide.

[0018] The lithium soap-based thickener is not particularly limited as long as it achieves the effects of the present invention. Lithium soap-based thickeners known as grease thickeners can be used. Examples include lithium soaps, which are lithium salts obtained by reacting lithium hydroxide with a fatty acid, and lithium complex soaps obtained by reacting lithium hydroxide with a fatty acid and an acid other than a fatty acid, such as one or more selected from dibasic acids, phosphoric acids, and aromatic carboxylic acids. Fatty acids having 10 to 24 carbon atoms are preferred, and the lithium soap-based thickener is preferably at least one selected from the group consisting of lithium stearate, lithium behenate, and lithium 12-hydroxystearate. Another example of the lithium soap-based thickener is a complex amide lithium soap, which uses an aliphatic monoamine in addition to the aforementioned components to introduce an amide bond into the molecule. The soap-based thickeners may be used alone or in combination of two or more, as long as they do not impair the effects of the present invention.

[0019] Examples of the non-soap thickener include urea thickeners containing urea compounds such as polyurea, fluorine thickeners containing fluororesins such as polytetrafluoroethylene, and organic thickeners such as sodium terephthalamate; as well as inorganic thickeners typified by organo-clays such as organo-bentonite, silica, etc. In one embodiment of the present invention, the non-soap thickener is preferably a urea thickener.

[0020] The urea-based thickener is not particularly limited as long as it achieves the effects of the present invention. Urea compounds known as grease thickeners can be used. Examples include urea-based compounds such as diurea compounds, triurea compounds, tetraurea compounds, and urea-urethane compounds obtained by reacting an isocyanate compound such as a polyisocyanate with an amine compound such as a monoamine. Among these, a preferred example is a diurea compound obtained by reacting a diisocyanate with a monoamine. The diisocyanate is preferably at least one selected from the group consisting of phenylene diisocyanate, diphenylmethane diisocyanate, tolylene diisocyanate, octadecane diisocyanate, decane diisocyanate, and hexane diisocyanate. The monoamine is preferably at least one selected from the group consisting of aliphatic monoamines, alicyclic monoamines, and aromatic monoamines. The aliphatic monoamine is preferably at least one selected from the group consisting of hexylamine, octylamine, dodecylamine, hexadecylamine, heptadecylamine, octadecylamine, and octadecenylamine. The alicyclic monoamine is preferably cyclohexylamine. The aromatic monoamine is preferably at least one selected from the group consisting of aniline and p-toluidine.

[0021] The urea-based thickener may be prepared, for example, by blending an isocyanate compound and an amine compound into a base oil, which is component (I), and reacting the isocyanate compound and the amine compound in the base oil to produce the urea compound. Alternatively, a base oil containing an isocyanate compound in advance and a base oil containing an amine compound in advance may be mixed, and then heated as necessary to react the isocyanate compound and the amine compound in the base oil to produce the urea compound. The urea-based thickener may be used alone or in combination of two or more, as long as it does not impair the effects of the present invention.

[0022] The content of component (II) in the grease composition can be adjusted appropriately according to the intended use of the resulting grease composition and the worked penetration required of the grease composition, etc. For example, in one embodiment of the present invention, the content of component (II) in the grease composition is preferably 1 to 40 mass%, more preferably 2 to 30 mass%, even more preferably 3 to 20 mass%, still more preferably 4 to 18 mass%, even more preferably 5 to 16 mass%, and even more preferably 7 to 13 mass%, relative to 100 mass% of the total amount of the grease composition.

[0023] <Component (III): Block Copolymer or Hydrogenated Product Thereof> The block copolymer or hydrogenated product thereof, which is component (III) (hereinafter also referred to as "component (III)"), contains a polymer block (A) and a polymer block (B). The polymer block (A) contains a structural unit (S) derived from an aromatic vinyl compound as a main structural unit. The polymer block (B) contains a structural unit (T) derived from a conjugated diene compound as a main structural unit, and also contains a structural unit (X) represented by formula (X). As will be described later, in this specification, the "block copolymer" also includes a "modified block copolymer," and similarly, the "hydrogenated product of a block copolymer (hereinafter also referred to as a "hydrogenated block copolymer")" also includes a "hydrogenated product of a modified block copolymer (hereinafter also referred to as a "modified hydrogenated product").

[0024] (Polymer Block (A)) The polymer block (A) (hereinafter also referred to as "polymer block (A)") constituting component (III) contains, as a main structural unit, a structural unit (S) (hereinafter also referred to as "structural unit (S)") derived from an aromatic vinyl compound.

[0025] [Structural Unit (S)] The statement that the polymer block (A) "contains the structural unit (S) as a main structural unit" means that, of the structural units contained in the polymer block (A), "the structural unit (S) is the structural unit with the largest content." For example, the content of the structural unit (S) in the polymer block (A) is preferably 30 mol % or more, more preferably 50 mol % or more, based on 100 mol % of the total amount of structural units constituting the polymer block (A). Furthermore, from the viewpoint of facilitating the production of a block copolymer or a hydrogenated product thereof, the content of the structural unit (S) in the polymer block (A) is more preferably 70 mol % or more, based on 100 mol % of the total amount of structural units constituting the polymer block (A). In other words, the content of the structural unit (S) is more preferably 70 to 100 mol % based on 100 mol % of the total amount of structural units constituting the polymer block (A). In particular, the content of the structural unit (S) is more preferably 80 to 100 mol%, even more preferably 90 to 100 mol%, even more preferably 95 to 100 mol%, even more preferably 98 to 100 mol%, and even more preferably 100 mol%, based on 100 mol% of the total amount of structural units constituting the polymer block (A). Herein, the phrase "100 mol% of the total amount of structural units constituting the polymer block (A)" does not include, for example, structural units unintentionally contained due to impurities in the polymerization solvent or monomers, as well as structural units derived from compounds other than the monomers, such as polymerization initiators, chain transfer agents, and coupling agents, which are necessary for polymerization. Furthermore, in the case of modification with a functional group, it also does not include structural units derived from the raw material into which the functional group is introduced.

[0026] Examples of the aromatic vinyl compound include styrene, o-methylstyrene, m-methylstyrene, p-methylstyrene, α-methylstyrene, β-methylstyrene, 2,6-dimethylstyrene, 2,4-dimethylstyrene, α-methyl-o-methylstyrene, α-methyl-m-methylstyrene, α-methyl-p-methylstyrene, β-methyl-o-methylstyrene, β-methyl-m-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, m-chlorostyrene, p-chlorostyrene, 2,6-dichlorostyrene, 2,4-dichlorostyrene, α-chloro-o-chlorostyrene, α-chloro-m-chlorostyrene, Examples of aromatic vinyl compounds include styrene-based compounds such as o-styrene, 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-bromomethylstyrene, m-bromomethylstyrene, p-bromomethylstyrene, and styrene derivatives substituted with silyl groups; indene; vinylnaphthalene; N-vinylcarbazole; and the like. These aromatic vinyl compounds may be used alone or in combination of two or more. That is, the structural unit (S) may be a structural unit derived from one type of aromatic vinyl compound, or may be a structural unit derived from two or more types of aromatic vinyl compounds. Among the above, from the viewpoint of the balance between production cost and physical properties, the aromatic vinyl compound preferably contains a styrene-based compound, more preferably styrene, α-methylstyrene, p-methylstyrene, or a mixture thereof, and even more preferably styrene.

[0027] Furthermore, from the viewpoint of making the effects of the present invention more easily obtainable, the content of the styrene-based compound in the aromatic vinyl compound is preferably 20 to 100 mass%, more preferably 40 to 100 mass%, even more preferably 45 to 100 mass%, still more preferably 55 to 100 mass%, still more preferably 75 to 100 mass%, still more preferably 90 to 100 mass%, and still more preferably 100 mass%, relative to the total amount (100 mass%) of the aromatic vinyl compounds constituting the polymer block (A).

[0028] Furthermore, the polymer block (A) preferably contains the structural unit (S) in the main chain of the polymer block (A). In this specification, the "main chain of the polymer block (A)" refers to the longest molecular chain in the molecular structure of the polymer block (A), which has a bonding moiety with the polymer block (B) at least at one end.

[0029] [Structural Unit (Q) Derived from Unsaturated Monomer Other Than Aromatic Vinyl Compound] Furthermore, as long as the objects and effects of the present invention are not hindered, polymer block (A) may contain a structural unit derived from an unsaturated monomer other than an aromatic vinyl compound (hereinafter also referred to as "structural unit (Q)") in a proportion of, for example, 30 mol% or less in polymer block (A). When polymer block (A) contains structural unit (Q), from the viewpoint of facilitating the production of a block copolymer or a hydrogenated product thereof, the content of structural unit (Q) in polymer block (A) is preferably 20 mol% or less, more preferably 10 mol% or less, even more preferably 5 mol% or less, and still more preferably 0 mol%, based on the total amount (100 mol%) of structural units constituting polymer block (A).

[0030] Examples of the unsaturated monomer other than the aromatic vinyl compound include at least one selected from the group consisting of butadiene, isoprene, 2,3-dimethylbutadiene, 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 unsaturated monomer units other than the aromatic vinyl compound, the bonding form is not particularly limited and may be either random or tapered.

[0031] {Weight-Average Molecular Weight (Mw) of Polymer Block (A)} The weight-average molecular weight (Mw) of the polymer block (A) is not particularly limited, but from the viewpoint of more easily achieving the effects of the present invention, the weight-average molecular weight (Mw) of at least one polymer block (A) among the polymer blocks (A) contained in component (III) is preferably 3,000 to 30,000, more preferably 3,500 to 20,000, and even more preferably 4,000 to 10,000. The numerical value of the weight-average molecular weight (Mw) of the polymer block (A) refers to the weight-average molecular weight (Mw) per polymer block (A).

[0032] In this specification, the weight average molecular weight (Mw) is a weight average molecular weight calculated in terms of standard polystyrene by gel permeation chromatography (GPC). Detailed measurement methods can be performed according to the methods described in the Examples. The weight average molecular weight of each polymer block (A) contained in component (III) can be determined by measuring a sampled liquid each time the polymerization of each polymer block is completed in the production process. For example, in the case of a triblock copolymer having an A1-B-A2 structure, the weight average molecular weight of the second polymer block A2 can be determined by determining the weight average molecular weights of the first polymer block A1 and polymer block B by the above-mentioned method and subtracting them from the weight average molecular weight of the block copolymer. Alternatively, in the case of a triblock copolymer having an A1-B-A2 structure, the total weight average molecular weight of the polymer blocks (A) can be calculated by subtracting the weight average molecular weight of the block copolymer from the weight average molecular weight of the first polymer block A1 and polymer block B.１ The weight average molecular weight of the second polymer block A2 can also be determined by calculating from the total content of polymer block (A) confirmed by H-NMR measurement, calculating the weight average molecular weight of the deactivated first polymer block A1 by GPC measurement, and subtracting this.

[0033] Furthermore, component (III) is required to have at least one polymer block (A). When component (III) has two or more polymer blocks (A), the multiple polymer blocks (A) may be the same or different. In this specification, "different polymer blocks" means that the polymer blocks are different in at least one of the monomer units constituting the polymer blocks, the weight-average molecular weight, the stereoregularity, and, if multiple monomer units are present, the ratio of the monomer units and the copolymerization form (random, tapered, block).

[0034] Furthermore, the content of polymer block (A) in component (III) is preferably 1 to 50% by mass, more preferably 1 to 30% by mass, even more preferably 1 to 25% by mass, even more preferably 1 to 18% by mass, even more preferably 3 to 16% by mass, and even more preferably 5 to 15% by mass, based on 100% by mass of the total amount of structural units constituting component (III). In this specification, the term "100% by mass of the total amount of structural units constituting component (III)" does not include, for example, structural units unintentionally contained due to impurities in the polymerization solvent or monomers, or structural units derived from compounds other than monomers, such as polymerization initiators, chain transfer agents, and coupling agents, which are necessary for polymerization. Furthermore, in the case of a component modified with a functional group, it does not include structural units derived from the raw material into which the functional group is introduced. When the content of the polymer block (A) in component (III) is 50% by mass or less, component (III) or a grease composition containing component (III) can be obtained that has excellent solubility in base oils and greases, does not decrease the tan δ peak top intensity, and is more likely to reduce noise or vibration. Furthermore, when the content of the polymer block (A) in component (III) is 1% by mass or more, component (III) can be easily produced, and a grease composition that is more likely to reduce noise or vibration can be more easily obtained. The content of the polymer block (A) in component (III) is １ The value was determined by H-NMR measurement, more specifically, the value was measured according to the method described in the Examples.

[0035] Furthermore, from the viewpoint of making it easier to reduce noise and vibration, the content of the structural units derived from the styrene-based compound in component (III) is preferably 1 to 25 mass%, more preferably 1 to 18 mass%, even more preferably 3 to 16 mass%, and still more preferably 5 to 15 mass%, relative to 100 mass% of the total amount of structural units constituting component (III).

[0036] (Polymer Block (B)) The polymer block (B) constituting component (III) (hereinafter also referred to as "polymer block (B)") contains a structural unit (T) (hereinafter also referred to as "structural unit (T)") derived from a conjugated diene compound as a main structural unit, and also contains a structural unit (X) (hereinafter also referred to as "structural unit (X)") represented by the following formula (X). Here, the structural unit (T) derived from a conjugated diene compound does not include the structural unit (X) represented by the following formula (X).

[0037] [Structural Unit (T)] The statement that the polymer block (B) "contains the structural unit (T) as a main structural unit" means that, among the structural units contained in the polymer block (B), "the structural unit (T) is the structural unit contained in the largest amount." For example, the content of the structural unit (T) in the polymer block (B) is preferably 30 mol % or more, more preferably 50 mol % or more, based on 100 mol % of the total amount of structural units constituting the polymer block (B). From the viewpoint of facilitating a reduction in noise and vibration, the total content of the structural unit (T) and the structural unit (X) represented by the following formula (X) in polymer block (B) is preferably 30 to 100 mol%, more preferably 50 to 100 mol%, even more preferably 65 to 100 mol%, still more preferably 80 to 100 mol%, even more preferably 90 to 100 mol%, still more preferably 95 to 100 mol%, still more preferably 98 to 100 mol%, and still more preferably 100 mol%. Furthermore, the content of the structural unit (T) in polymer block (B) is preferably 99.5 mol% or less, more preferably 99.2 mol% or less, and even more preferably 99.0 mol% or less, based on 100 mol% of the total amount of structural units constituting polymer block (B). The lower limit of the content of the structural unit (T) in the polymer block (B) is not particularly limited as long as it is within a range that does not impair the effects of the present invention, but from the viewpoint of productivity and from the viewpoint of making the effects of the present invention more easily obtainable, it is preferably 60 mol% or more, more preferably 70 mol% or more, even more preferably 80 mol% or more, and even more preferably 82 mol% or more. Furthermore, from the viewpoint of making the low-temperature properties of the obtained grease composition more easily excellent, the lower limit of the content of the structural unit (T) in the polymer block (B) is even more preferably 88 mol% or more, even more preferably 92.0 mol% or more, even more preferably 95.0 mol% or more, even more preferably 97.0 mol% or more, and even more preferably 97.5 mol% or more. As mentioned above, these lower and upper limits described in stages can be independently combined.For example, in one embodiment of the present invention, the content of the structural unit (T) in the polymer block (B) is preferably 60 to 99.5 mol%, more preferably 70 to 99.5 mol%, even more preferably 80 to 99.5 mol%, still more preferably 82 to 99.5 mol%, still more preferably 88 to 99.5 mol%, still more preferably 92.0 to 99.5 mol%, still more preferably 95.0 to 99.5 mol%, still more preferably 97.0 to 99.5 mol%, still more preferably 97.0 to 99.2 mol%, still more preferably 97.0 to 99.0 mol%, and still more preferably 97.5 to 99.0 mol%, based on 100 mol% of the total amount of structural units constituting the polymer block (B). In this specification, the term "100 mol % of the total amount of structural units constituting polymer block (B)" does not include, for example, structural units unintentionally contained due to impurities in the polymerization solvent or monomers, or structural units derived from compounds other than monomers that are necessary for polymerization, such as polymerization initiators, chain transfer agents, and coupling agents. Furthermore, in the case of a polymer block modified with a functional group, this does not include structural units derived from the raw material into which the functional group is introduced.

[0038] Furthermore, the polymer block (B) preferably contains the structural unit (T) in the main chain of the polymer block (B). In this specification, the "main chain of the polymer block (B)" refers to the longest molecular chain in the molecular structure of the polymer block (B), which has a bonding moiety with the polymer block (A) at least at one end.

[0039] Examples of the conjugated diene compound include butadiene, isoprene, hexadiene, 2,3-dimethyl-1,3-butadiene, 1,3-pentadiene, β-farnesene, and myrcene. Among these, the conjugated diene compound preferably contains one or more selected from butadiene and isoprene, more preferably contains isoprene or both isoprene and butadiene, and even more preferably contains isoprene. That is, the conjugated diene compound preferably contains isoprene. Furthermore, from the viewpoint of more easily achieving the effects of the present invention, the content of isoprene in the conjugated diene compound is preferably 20 to 100% by mass, more preferably 40 to 100% by mass, even more preferably 45 to 100% by mass, still more preferably 55 to 100% by mass, still more preferably 75 to 100% by mass, still more preferably 90 to 100% by mass, and even more preferably 100% by mass, based on 100% by mass of the total amount of the conjugated diene compounds constituting the polymer block (B).

[0040] Furthermore, when the conjugated diene compound contains both butadiene and isoprene, the total content of butadiene and isoprene in the conjugated diene compound is preferably 25 to 100 mass%, more preferably 45 to 100 mass%, even more preferably 50 to 100 mass%, still more preferably 60 to 100 mass%, still more preferably 80 to 100 mass%, still more preferably 95 to 100 mass%, and still more preferably 100 mass%, based on 100 mass% of the total amount of the conjugated diene compounds constituting the polymer block (B).

[0041] When butadiene and isoprene are used in combination as the conjugated diene compound, the blending ratio [isoprene / butadiene] (mass ratio) thereof is not particularly limited, but is preferably 5 / 95 to 95 / 5, more preferably 10 / 90 to 90 / 10, even more preferably 40 / 60 to 70 / 30, and still more preferably 45 / 55 to 65 / 35. When expressed as a molar ratio, the blending ratio [isoprene / butadiene] is preferably 5 / 95 to 95 / 5, more preferably 10 / 90 to 90 / 10, even more preferably 40 / 60 to 70 / 30, and still more preferably 45 / 55 to 55 / 45.

[0042] [Structural Unit (X)] The structural unit (X) is a structural unit represented by the following formula (X). The structural unit (X) may be a structural unit derived from a conjugated diene compound, or may be a structural unit derived from a compound other than a conjugated diene compound, as long as it is represented by the following formula (X). The conjugated diene compound serving as a raw material for the structural unit (X) can be the same as the conjugated diene compound described above, and the preferred embodiments thereof are also the same. From the viewpoint of facilitating the formation of the structural unit (X), it is preferable that the structural unit (X) is a structural unit derived from a conjugated diene compound. Even when the structural unit (X) is a structural unit derived from a conjugated diene compound, the structural unit (X) is not included in one of the structural units (T). In other words, the content of the structural unit (T) in the polymer block (B) described above represents the content of structural units derived from conjugated diene compounds other than the structural unit (X). The same applies to the content of isoprene or the total content of butadiene and isoprene in the conjugated diene compound described above.

[0043] Furthermore, the polymer block (B) may contain the structural unit (X) in the main chain or side chain of the polymer block (B), but it is preferable that the structural unit (X) be contained in the main chain of the polymer block (B). It is believed that the incorporation of the structural unit (X) in the main chain of the polymer block (B) reduces molecular motion, thereby increasing the glass transition temperature of the component (III) and improving the peak top intensity of tan δ around room temperature. One or more structural units (X) may be contained in the main chain of the polymer block (B), or the structural unit (X) may be contained as a repeating unit.

[0044]

[0045] In the formula (X), R １ ~R ３ are each independently a hydrogen atom or a hydrocarbon group having 1 to 11 carbon atoms. When the polymer block (B) contains two or more structural units (X), the plurality of R １ may be the same or different, and there are multiple R ２ may be the same or different, and there are multiple R３ may be the same or different. The hydrocarbon group having 1 to 11 carbon atoms is preferably a hydrocarbon group having 1 to 5 carbon atoms, more preferably a hydrocarbon group having 1 to 3 carbon atoms, and even more preferably a methyl group. The hydrocarbon group may be a linear or branched chain, and may be a saturated or unsaturated hydrocarbon group. From the viewpoint of the physical properties of component (III) and the formation of structural unit (X), R １ ~R ３ are each independently a hydrogen atom or a methyl group. When the block copolymer is hydrogenated, the vinyl group in the formula (X) can be hydrogenated. Therefore, the structural unit (X) in the hydrogenated product includes the carbon-carbon double bond portion (R ３ is a hydrogen atom, it is a vinyl group) and a structural unit in which the alkyl group is hydrogenated is also included.

[0046] As a specific example, the structural unit (X) mainly produced when butadiene, isoprene, or a combination of butadiene and isoprene is used as the conjugated diene compound will be described. When butadiene is used alone as the conjugated diene compound, only the structural unit (Xh) having the combination of the following substituents (i) is produced. Therefore, when butadiene is used alone as the conjugated diene compound, the polymer block (B) is formed by combining the following substituents: １ ~R ３ In one embodiment of the present invention, the polymer block (B) contains, as the structural unit (X), only the structural unit (Xh) in which R １ ~R ３ It is preferable that the polymer block (B) contains a structural unit (Xh) in which all of the following are hydrogen atoms, and it is more preferable that the structural unit (Xh) is contained in the main chain of the polymer block (B).

[0047] When isoprene is used alone as the conjugated diene compound, two types of structural units (X) having the following combinations of substituents (v) and (vi) are mainly produced. When butadiene and isoprene are used in combination as the conjugated diene compound, six types of structural units (X) having the following combinations of substituents (i) to (vi) are mainly produced. (i) : R １ = hydrogen atom, R ２ = hydrogen atom, R ３ = hydrogen atom (ii): R １ = hydrogen atom, R ２ = methyl group, R ３ = hydrogen atom (iii): R １ = hydrogen atom, R ２ = hydrogen atom, R ３ = methyl group (iv): R １ = methyl group, R ２ = hydrogen atom, R ３ = Hydrogen atom (v): R １ = methyl group, R ２ = methyl group, R ３ = hydrogen atom (vi): R １ = methyl group, R ２ = hydrogen atom, R ３ = methyl group

[0048] In the formula (X), at least one structural unit (X) in the polymer block (B) is preferably a hydrocarbon group, because the hydrocarbon group has a substituent that reduces molecular motion and makes it easier to further reduce noise or vibration. １ ~R ３ In other words, in one embodiment of the present invention, the polymer block (B) preferably contains, as the structural unit (X), at least one of the structural units (Xc) represented by the formula (X), R １ ~R ３It is preferable that the polymer block (B) contains a structural unit (Xc) in which at least one of the structural units (Xc) is a hydrocarbon group having 1 to 11 carbon atoms, and it is more preferable that the structural unit (Xc) is contained in the main chain of the polymer block (B). Among these, it is more preferable that the hydrocarbon group having 1 to 11 carbon atoms in the structural unit (Xc) is a methyl group, from the viewpoint of efficiently producing the structural unit (Xc) from a conjugated diene compound and more easily achieving the effects of the present invention. In particular, １ ~R ３ each independently represents a hydrogen atom or a methyl group, and R １ ~R ３ and (ii) are not simultaneously hydrogen atoms. That is, polymer block (B) more preferably contains, as structural unit (X), at least one of the structural units (Xc) having the combination of substituents (ii) to (vi) described above, and further preferably contains, in the main chain of polymer block (B), at least one of the structural units (Xc) having the combination of substituents (ii) to (vi) described above.

[0049] {Amount of Vinyl Bonds in Polymer Block (B)} When the structural units constituting the polymer block (B) are any of an isoprene unit, a butadiene unit, and a mixed unit of isoprene and butadiene, the bond forms of the isoprene and butadiene other than the bond form forming the structural unit (X) can be 1,2-bonds or 1,4-bonds in the case of butadiene, and 1,2-bonds, 3,4-bonds or 1,4-bonds in the case of isoprene.

[0050] In the block copolymer and its hydrogenated product, the total ratio of the content of 3,4-bond units and 1,2-bond units to the content of all bond units in the polymer block (B) (hereinafter, sometimes simply referred to as "vinyl bond content") is preferably 55 to 99 mol%, more preferably 60 to 95 mol%, and even more preferably 60 to 85 mol%. The above ranges are preferred because the effects of the present invention are more easily achieved. Here, the "vinyl bond content" is determined according to the method described in the Examples, １It is a value calculated by H-NMR measurement. When the polymer block (B) is composed only of butadiene, the above-mentioned "content of 3,4-bond units and 1,2-bond units" is read as "content of 1,2-bond units" and applied.

[0051] {Content of Structural Unit (X)} From the viewpoint of more easily achieving the effects of the present invention, the content of the structural unit (X) in the polymer block (B) is preferably 0.5 mol% or more, more preferably 0.8 mol% or more, and even more preferably 1.0 mol% or more, based on 100 mol% of the total amount of structural units constituting the polymer block (B). The upper limit of the content of the structural unit (X) in the polymer block (B) is not particularly limited as long as it is within a range that does not impair the effects of the present invention. However, from the viewpoint of productivity and more easily achieving the effects of the present invention, it is preferably 40 mol% or less, more preferably 30 mol% or less, even more preferably 20 mol% or less, and even more preferably 18 mol% or less. From the viewpoint of more easily achieving excellent low-temperature properties of the resulting grease composition, the upper limit of the content of the structural unit (X) in the polymer block (B) is even more preferably 12 mol% or less, even more preferably 8.0 mol% or less, even more preferably 5.0 mol% or less, even more preferably 3.0 mol% or less, and even more preferably 2.5 mol% or less. As described above, these stepwise lower and upper limits can be independently combined. For example, in one embodiment of the present invention, the content of the structural unit (X) in the polymer block (B) is preferably 0.5 to 40 mol%, more preferably 0.5 to 30 mol%, even more preferably 0.5 to 20 mol%, still more preferably 0.5 to 18 mol%, even more preferably 0.5 to 12 mol%, still more preferably 0.5 to 8.0 mol%, still more preferably 0.5 to 5.0 mol%, still more preferably 0.5 to 3.0 mol%, still more preferably 0.8 to 3.0 mol%, still more preferably 1.0 to 3.0 mol%, and still more preferably 1.0 to 2.5 mol%, based on 100 mol% of the total amount of structural units constituting the polymer block (B).

[0052] From the viewpoint of more easily achieving the effects of the present invention, the content of the structural unit (Xc) in the polymer block (B) is preferably 0.5 mol% or more, more preferably 0.8 mol% or more, and even more preferably 1.0 mol% or more, based on 100 mol% of the total amount of structural units constituting the polymer block (B). The upper limit of the content of the structural unit (Xc) in the polymer block (B) is not particularly limited as long as it is within a range that does not impair the effects of the present invention. However, from the viewpoint of productivity and more easily achieving the effects of the present invention, the content is preferably 40 mol% or less, more preferably 30 mol% or less, even more preferably 20 mol% or less, still more preferably 15 mol% or less, and even more preferably 10 mol% or less, based on 100 mol% of the total amount of structural units constituting the polymer block (B). Furthermore, from the viewpoint of making the obtained grease composition more likely to have excellent low-temperature properties, the upper limit of the content of the structural unit (Xc) in the polymer block (B) is even more preferably 9.0 mol% or less, even more preferably 8.0 mol% or less, even more preferably 5.0 mol% or less, even more preferably 3.0 mol% or less, and even more preferably 2.5 mol% or less, based on 100 mol% of the total amount of structural units constituting the polymer block (B). As mentioned above, these stepwise lower and upper limits can be independently combined. For example, in one embodiment of the present invention, the content of the structural unit (Xc) in the polymer block (B) is preferably 0.5 to 40 mol%, more preferably 0.5 to 30 mol%, even more preferably 0.5 to 20 mol%, still more preferably 0.5 to 15 mol%, still more preferably 0.5 to 10 mol%, still more preferably 0.5 to 9.0 mol%, still more preferably 0.5 to 8.0 mol%, still more preferably 0.5 to 5.0 mol%, still more preferably 0.5 to 3.0 mol%, still more preferably 0.8 to 3.0 mol%, still more preferably 1.0 to 3.0 mol%, and still more preferably 1.0 to 2.5 mol%, based on 100 mol% of the total amount of structural units constituting the polymer block (B).

[0053] Furthermore, for example, when isoprene is used as the conjugated diene compound, or when butadiene and isoprene are used in combination as the conjugated diene compounds, when one or more structural units (Xc) having a combination of the substituents (ii), (iii), (v), or (vi) are present in the polymer block (B), the total content thereof is not particularly limited as long as it is within a range that does not impair the effects of the present invention. From the viewpoint of making the effects of the present invention more easily exhibited, the total content is preferably 0.5 mol % or more, more preferably 0.8 mol % or more, and even more preferably 1.0 mol % or more, relative to the total amount (100 mol %) of the structural units constituting the polymer block (B). In a similar case, when one or more structural units (Xc) having a combination of the substituents (ii), (iii), (v), or (vi) are present in the polymer block (B), the upper limit of their total content is not particularly limited as long as it is within a range that does not impair the effects of the present invention, but from the viewpoints of productivity and making the effects of the present invention more easily obtainable, it is preferably 40 mol% or less, more preferably 30 mol% or less, even more preferably 20 mol% or less, still more preferably 15 mol% or less, and even more preferably 10 mol% or less. In a similar case, from the viewpoint of making the obtained grease composition more likely to have excellent low-temperature properties, when one or more structural units (Xc) having a combination of the substituents (ii), (iii), (v), or (vi) are present in the polymer block (B), the upper limit of their total content is even more preferably 9.0 mol% or less, even more preferably 8.0 mol% or less, even more preferably 5.0 mol% or less, even more preferably 3.0 mol% or less, and even more preferably 2.5 mol% or less. As mentioned above, the lower limit and upper limit values ​​described in stages can be independently combined.For example, in one embodiment of the present invention, when one or more structural units (Xc) having a combination of the substituents (ii), (iii), (v), or (vi) are present in polymer block (B), the total content thereof is preferably 0.5 to 40 mol%, more preferably 0.5 to 30 mol%, even more preferably 0.5 to 20 mol%, still more preferably 0.5 to 15 mol%, still more preferably 0.5 to 10 mol%, still more preferably 0.5 to 9.0 mol%, still more preferably 0.5 to 8.0 mol%, still more preferably 0.5 to 5.0 mol%, still more preferably 0.5 to 3.0 mol%, still more preferably 0.8 to 3.0 mol%, still more preferably 1.0 to 3.0 mol%, and still more preferably 1.0 to 2.5 mol%, based on 100 mol% of the total amount of structural units constituting polymer block (B).

[0054] In addition, when butadiene and isoprene are used in combination as the conjugated diene compound, when one or more structural units (X) having a combination of the substituents (i) to (vi) are present in polymer block (B), the total content thereof is not particularly limited as long as it is within a range that does not impair the effects of the present invention, but from the viewpoint of more easily achieving the effects of the present invention, it is preferably 0.5 mol % or more, more preferably 0.8 mol % or more, and even more preferably 1.0 mol % or more, based on 100 mol % of the total amount of structural units constituting polymer block (B). In a similar case, when one or more structural units (X) having a combination of the substituents (i) to (vi) are present in polymer block (B), the upper limit of their total content is not particularly limited as long as it is within a range that does not impair the effects of the present invention, but from the viewpoint of productivity and more easily achieving the effects of the present invention, it is preferably 40 mol % or less, more preferably 30 mol % or less, even more preferably 20 mol % or less, and even more preferably 18 mol % or less, based on 100 mol % of the total amount of structural units constituting polymer block (B). In a similar case, from the viewpoint that the resulting grease composition is more likely to have excellent low-temperature properties, when one or more structural units (X) having a combination of the substituents (i) to (vi) are present in polymer block (B), the total content thereof is even more preferably 12 mol% or less, even more preferably 8.0 mol% or less, even more preferably 5.0 mol% or less, even more preferably 3.0 mol% or less, and even more preferably 2.5 mol% or less, based on 100 mol% of the total amount of structural units constituting polymer block (B). As mentioned above, these stepwise lower limit values ​​and upper limit values ​​can be independently combined.For example, in one embodiment of the present invention, when one or more structural units (X) having a combination of the substituents (i) to (vi) are present in polymer block (B), the total content thereof is preferably 0.5 to 40 mol%, more preferably 0.5 to 30 mol%, even more preferably 0.5 to 20 mol%, still more preferably 0.5 to 18 mol%, even more preferably 0.5 to 12 mol%, still more preferably 0.5 to 8.0 mol%, still more preferably 0.5 to 5.0 mol%, still more preferably 0.5 to 3.0 mol%, still more preferably 0.8 to 3.0 mol%, still more preferably 1.0 to 3.0 mol%, and still more preferably 1.0 to 2.5 mol%, based on 100 mol% of the total amount of structural units constituting polymer block (B).

[0055] The content of the structural unit (X) (including (Xc) and (Xh)) contained in the block copolymer or its hydrogenated product is １３ It is a value determined from the integral value derived from the structural unit (X) in the polymer block (B) by C-NMR measurement, and more specifically, it is a value measured according to the method described in the Examples.

[0056] {Hydrogenation Rate of Polymer Block (B)} From the viewpoint of more easily achieving the effects of the present invention, component (III) is preferably a hydrogenated product of a block copolymer in which the hydrogenation rate of the polymer block (B) is 50 to 100 mol%. From the same viewpoint, the hydrogenation rate of the polymer block (B) is more preferably 50 to 99 mol%, even more preferably 75 to 99 mol%, still more preferably 80 to 99 mol%, even more preferably 80 to 98 mol%, and still more preferably 85 to 96 mol%. In one embodiment of the present invention, the hydrogenation rate of the polymer block (B) may be 0 mol% or more but less than 50 mol%. The hydrogenation rate is determined by calculating the content of carbon-carbon double bonds derived from the conjugated diene compound and the structural unit (X) in the polymer block (B) as follows: １ It is a value that can be determined by H-NMR measurement, more specifically, a value measured according to the method described in the Examples.

[0057] Furthermore, when the hydrogenation rate of the polymer block (B) is 0 mol % or more and less than 50 mol %, the component (III) can specify the molar ratio of the carbon-carbon double bonds contained in the structural unit (X) to the carbon-carbon double bonds contained in the main chain of the polymer block (B). For example, in the structural unit (Xc) having a combination of the substituents (ii), (iii), (v), or (vi), the molar ratio of the carbon atom at the terminal of the carbon-carbon double bond contained in the structural unit (Xc) (the carbon atom (a) in the following chemical formula) can be specified. １３ The chemical shift in C-NMR appears around 107 to 110 ppm, which corresponds to the carbon atom at the end of the carbon-carbon double bond contained in the main chain of the polymer block (B) (carbon atom (b) in the following chemical formula). １３ The chemical shift in C-NMR appears around 110 to 116 ppm. When the hydrogenation rate of the polymer block (B) is 0 mol % or more and less than 50 mol %, 13 The peak area ratio measured by C-NMR [peak area having a chemical shift value of 107 ppm or more and less than 110 ppm] / [peak area having a chemical shift value of 110 ppm or more and less than 116 ppm] is usually in the range of 0.01 to 3.00, and from the viewpoint of making the effects of the present invention more easily exhibited, the area ratio is preferably 0.01 to 1.50, more preferably 0.01 to 1.00, even more preferably 0.01 to 0.50, and still more preferably 0.01 to 0.20.

[0058]

[0059] In addition, for component (III), １３ In the C-NMR measurement, peaks due to carbon atoms on the five-membered ring composed of carbon atoms in the structural unit (X) are hardly observed, but the substituent R ３ is a hydrocarbon group having 1 to 11 carbon atoms, and R ３ Thus, for example, in the case of a hydrogenated product of the block copolymer in component (III), when the hydrogenation rate of the polymer block (B) is 50 to 99 mol %, the peak derived from the carbon atom on the 5-membered ring composed of the carbon atom in the structural unit (Xc) bonded to the branched alkyl group derived from the carbon-carbon double bond having the formula: ３It is also possible to specify the molar ratio of the carbon atoms on the five-membered ring composed of carbon atoms in the structural unit (Xc) bonded to the branched alkyl group derived from the carbon-carbon double bond, and the carbon atoms on the main chain of the polymer block (B) bonded to the branched alkyl group derived from the carbon-carbon double bond.

[0060] For example, in the structural unit (Xc) having the combination of the substituents (iii) or (vi), the carbon atom on the five-membered ring composed of the carbon atom in the structural unit (X) bonded to the isoprene group (the carbon atom (c) in the following chemical formula) １３ The chemical shift in C-NMR appears around 50 to 52 ppm, which corresponds to the carbon atom (carbon atom (d) in the following chemical formula) on the main chain of the polymer block (B) that is bonded to the isoprene group. １３ The chemical shift in C-NMR appears around 43 to 45 ppm. For example, when the hydrogenation rate is 40 to 99 mol%, 13 The peak area ratio measured by C-NMR [peak area with chemical shift values ​​of 50 ppm or more and 52 ppm or less] / [peak area with chemical shift values ​​of 43 ppm or more and 45 ppm or less] is usually in the range of 0.01 to 3.00, and from the viewpoint of more easily achieving the effects of the present invention, this area ratio is preferably in the range of 0.01 to 1.50, more preferably in the range of 0.01 to 1.00, even more preferably in the range of 0.01 to 0.50, and still more preferably in the range of 0.01 to 0.25. The peak area ratio can be measured in more detail according to the method described in the Examples.

[0061]

[0062] {Weight Average Molecular Weight (Mw) of Polymer Block (B)} From the viewpoint of more easily achieving the effects of the present invention, the total weight average molecular weight (Mw) of the polymer blocks (B) in the block copolymer before hydrogenation is preferably 10,000 to 400,000, more preferably 30,000 to 300,000, even more preferably 50,000 to 250,000, still more preferably 70,000 to 200,000, still more preferably 90,000 to 180,000, and even more preferably 100,000 to 170,000. Note that the numerical value of the weight average molecular weight (Mw) of the polymer block (B) refers to the weight average molecular weight (Mw) per polymer block (B).

[0063] [Other structural units (U) in polymer block (B)] The polymer block (B) may contain a structural unit (U) other than the structural units (T) and (X), as long as the purpose and effects of the present invention are not impaired. In the polymer block (B), the content of the structural unit (U) is preferably 0 to 50 mol %, more preferably 0 to 30 mol %, even more preferably 0 to 20 mol %, still more preferably 0 to 10 mol %, and still more preferably 0 mol %, based on 100 mol % of the total amount of structural units constituting the polymer block (B). Preferred examples of polymerizable monomers that can be used as raw materials for the structural unit (U) include aromatic vinyl compounds such as styrene, α-methylstyrene, o-methylstyrene, m-methylstyrene, p-methylstyrene, p-t-butylstyrene, 2,4-dimethylstyrene, N-vinylcarbazole, vinylnaphthalene, and vinylanthracene, as well as at least one compound selected from the group consisting of methyl methacrylate, methyl vinyl ether, β-pinene, 8,9-p-menthene, dipentene, methylenenorbornene, 2-methylenetetrahydrofuran, 1,3-cyclopentadiene, 1,3-cyclohexadiene, 1,3-cycloheptadiene, and 1,3-cyclooctadiene.

[0064] Component (III) may have at least one polymer block (B). When component (III) has two or more polymer blocks (B), the multiple polymer blocks (B) may be the same or different.

[0065] {Iodine Value of Component (III)} From the viewpoint of more easily achieving the effects of the present invention, component (III) is preferably a hydrogenated product of a block copolymer having an iodine value of 0 to 200 g / 100 g. From the same viewpoint, the iodine value is more preferably 3 to 200 g / 100 g, even more preferably 3 to 100 g / 100 g, still more preferably 3 to 80 g / 100 g, even more preferably 5 to 80 g / 100 g, still more preferably 10 to 70 g / 100 g, and even more preferably 15 to 60 g / 100 g. The iodine value is a value measured in detail according to the method described in the Examples.

[0066] Furthermore, the content of polymer block (B) in component (III) is preferably 50 to 99 mass%, more preferably 70 to 99 mass%, even more preferably 75 to 99 mass%, still more preferably 82 to 99 mass%, still more preferably 84 to 97 mass%, and even more preferably 85 to 95 mass%, based on 100 mass% of the total amount of structural units constituting component (III).

[0067] (Bonding Mode Between Polymer Block (A) and Polymer Block (B)) The bonding mode of component (III) is not limited as long as polymer block (A) and polymer block (B) are bonded together, and may be linear, branched, radial, or a combination of two or more of these. Among these, the bonding mode between polymer block (A) and polymer block (B) is preferably linear. Examples of such a bonding mode include, when polymer block (A) is represented by A and polymer block (B) is represented by B, a diblock copolymer represented by A-B, a triblock copolymer represented by A-B-A or B-A-B, a tetrablock copolymer represented by A-B-A-B, a pentablock copolymer represented by A-B-A-B-A or B-A-B-A-B, and (A-B) ｎZ-type copolymers (where Z represents a coupling agent residue, and n represents an integer of 3 or greater) are also suitable. Among these, linear triblock copolymers or diblock copolymers are preferred, and A-B-A type triblock copolymers are preferably used from the viewpoint of ease of production of component (III).

[0068] Here, in the present specification, when polymer blocks of the same type are linearly bonded via a bifunctional coupling agent or the like, the entire bonded polymer blocks are treated as a single polymer block. Accordingly, including the above examples, polymer blocks that should strictly be expressed as Y-Z-Y (Z represents a coupling residue) are expressed as Y as a whole, unless it is particularly necessary to distinguish them from a single polymer block Y. In the present specification, since this type of polymer block containing a coupling agent residue is treated as above, for example, a block copolymer containing a coupling agent residue and that should strictly be expressed as A-B-Z-B-A (Z represents a coupling agent residue) is expressed as A-B-A and is treated as an example of a triblock copolymer.

[0069] (Total Content of Polymer Block (A) and Polymer Block (B)) Component (III) may contain a polymer block constituted of a monomer other than the polymer blocks (A) and (B) as long as the object and effects of the present invention are not hindered. From the viewpoint of making the effects of the present invention more easily obtainable, the total content of polymer block (A) and polymer block (B) in component (III) is preferably 90 to 100% by mass, more preferably 95 to 100% by mass, even more preferably 98 to 100% by mass, and still more preferably 100% by mass, based on 100% by mass of the total amount of structural units constituting component (III).

[0070] (Functional Group) Component (III) may also be a modified block copolymer or a hydrogenated product thereof (modified hydrogenated product) having at least one functional group selected from an alkoxysilyl group, a carboxy group, an amino group, a hydroxy group, an epoxy group, and a group derived from an acid anhydride. The modified block copolymer or the modified hydrogenated product can be produced, for example, by reacting the aforementioned block copolymer or a hydrogenated product thereof with a compound having at least one functional group selected from an alkoxysilyl group, a carboxy group, an amino group, a hydroxy group, an epoxy group, and a group derived from an acid anhydride to introduce the functional group, thereby modifying the aforementioned block copolymer or a hydrogenated product thereof. The functional group is preferably one or more functional groups selected from an alkoxysilyl group and a group derived from an acid anhydride, and more preferably a functional group derived from an acid anhydride. Examples of the acid anhydride include unsaturated carboxylic acid anhydrides such as maleic anhydride, citraconic anhydride, 2,3-dimethylmaleic anhydride, and itaconic anhydride. Among these, maleic anhydride is preferred. Furthermore, when component (III) has a functional group, it is preferable that the functional group be present on a side chain, which is thought to increase the difference in molecular mobility between the main chain and the side chain, thereby controlling the glass transition temperature and making it easier to reduce noise or vibration over a wide temperature range.

[0071] When component (III) has a functional group, the content of the functional group in component (III) is preferably 0.1 to 5.0 phr, more preferably 0.15 to 4.0 phr, even more preferably 0.2 to 3.0 phr, still more preferably 0.25 to 2.0 phr, even more preferably 0.3 to 1.0 phr, still more preferably 0.4 to 0.9 phr, and even more preferably 0.50 to 0.70 phr. The content (phr) of the functional group refers to the parts by mass of the functional group per 100 parts by mass of component (III), and can be calculated, for example, as the parts by mass of the modifier used to introduce the functional group per 100 parts by mass of component (III). The content of the functional group in component (III) can be measured in more detail according to the method described in the Examples.

[0072] (Weight-Average Molecular Weight (Mw) of Component (III)) The weight-average molecular weight (Mw) of component (III) is not particularly limited as long as it does not interfere with the objects and effects of the present invention. From the viewpoint of making it easier to achieve the effects of the present invention, however, it is preferably 15,000 to 450,000, more preferably 50,000 to 350,000, even more preferably 70,000 to 300,000, still more preferably 90,000 to 250,000, still more preferably 100,000 to 200,000, and still more preferably 110,000 to 180,000.

[0073] (Tan δ Peak Top Temperature and Strength of Component (III)) Tan δ (loss tangent) is the ratio of loss modulus / storage modulus at a frequency of 1 Hz in dynamic viscoelastic measurement, and the tan δ peak top temperature and strength contribute significantly to the vibration damping properties and other physical properties of component (III). Here, the tan δ peak top strength refers to the value of tan δ when the tan δ peak is maximum. Furthermore, the tan δ peak top temperature refers to the temperature when the tan δ peak is maximum.

[0074] In the present invention, component (III) is pressurized at 230°C and 10 MPa for 3 minutes to produce a single-layer sheet having a thickness of 1.0 mm, which is then cut into a disk-shaped test piece, and the peak-top strength and temperature of tan δ are measured using the test piece. The measurement conditions are in accordance with JIS K7244-10:2005: strain 0.1%, frequency 1 Hz, measurement temperature -70 to +100°C, and heating rate 3°C / min.

[0075] The tan δ peak top intensity of component (III) measured by the above measurement is preferably 1.0 or higher, more preferably 1.5 or higher, even more preferably 1.9 or higher, and even more preferably 2.0 or higher. The higher the tan δ peak top intensity, the more easily component (III) reduces vibration or noise at that temperature. The upper limit of the tan δ peak top intensity may be within a range that does not impair the effects of the present invention, and may be, for example, 3.0 or lower. From the viewpoint of facilitating the achievement of the effects of the present invention, the tan δ peak top temperature of component (III) is preferably −50°C or higher, more preferably −40°C or higher, even more preferably −30°C or higher, and even more preferably −25°C or higher, and may even be 0°C or higher. In one embodiment of the present invention, the tan δ peak top temperature of component (III) may be 20°C or higher, or may be 30°C or higher. The upper limit of the tan δ peak top temperature may be within a range that does not impair the effects of the present invention, and may be 50° C. or less, 45° C. or less, 40° C. or less, or 35° C. or less. The range of the tan δ peak top temperature is, for example, preferably −50 to +50° C., more preferably −40 to +45° C., even more preferably −30 to +40° C., and still more preferably −25 to +35° C.

[0076] (Maximum width of temperature range in which tan δ of component (III) is 1.0 or greater) Furthermore, component (III) has a series of temperature ranges in which tan δ from −70 to +100° C. is 1.0 or greater, measured under the above measurement conditions, and the maximum width of this temperature range is preferably 12° C. or greater, more preferably 13° C. or greater, even more preferably 15° C. or greater, and still more preferably 17° C. or greater. A wider temperature range in which component (III) exhibits tan δ of 1.0 or greater enables component (III) to reduce vibration or noise over a wider temperature range, which is preferable because adding component (III) to a grease composition makes it easier to achieve the effects of the present invention.

[0077] (Method for Producing Component (III)) [Method for Producing Block Copolymer] As a method for producing a block copolymer according to component (III), for example, one or more conjugated diene compounds are polymerized by anionic polymerization to form a polymer block (B) having the structural unit (X) (preferably, a polymer block (B) having the structural unit (X) in the main chain of the polymer block (B)), and then a monomer for the polymer block (A) is added, and if necessary, a monomer for the polymer block (A) and a conjugated diene compound are further sequentially added to obtain a block copolymer. The structural unit (X) can be produced by anionic polymerization using known techniques (see, for example, U.S. Pat. No. 3,966,691). The structural unit (X) is formed at the end of the polymer upon monomer depletion, and polymerization can be restarted from the structural unit (X) by sequentially adding further monomer. Therefore, the presence or absence of the structural unit (X) and its content can be controlled by adjusting the time for sequential addition of the monomer, the polymerization temperature, the type and amount of the catalyst, the combination of the monomer and the catalyst, etc. In the anionic polymerization method, an anionic polymerization initiator, a solvent, and, if necessary, a Lewis base can be used.

[0078] In the above method, the organolithium compound that can be used as the polymerization initiator for the anionic polymerization is preferably at least one selected from the group consisting of methyllithium, ethyllithium, n-butyllithium, sec-butyllithium, tert-butyllithium, and pentyllithium. Furthermore, the dilithium compound that can be used as the polymerization initiator is preferably at least one selected from the group consisting of naphthalenedilithium and dilithiohexylbenzene. The coupling agent is preferably at least one selected from the group consisting of dichloromethane, dibromomethane, dichloroethane, dibromoethane, dibromobenzene, and phenyl benzoate. The amounts of these polymerization initiators and coupling agents used are determined appropriately depending on the desired weight-average molecular weight of the block copolymer and its hydrogenated product, which are the target component (III). Usually, the initiator such as an alkyllithium compound or a dilithium compound is preferably used in a proportion of 0.01 to 0.2 parts by mass per 100 parts by mass of the total of the monomers such as the aromatic vinyl compound and the conjugated diene compound used in the polymerization, and when a coupling agent is used, it is preferably used in a proportion of 0.001 to 0.8 parts by mass per 100 parts by mass of the total of the monomers.

[0079] The solvent is not particularly limited as long as it does not adversely affect the anionic polymerization reaction, and examples thereof 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 carried out at a temperature of preferably 0 to 100°C, more preferably 10 to 70°C, for preferably 0.5 to 50 hours, more preferably 1 to 30 hours.

[0080] Furthermore, by adding a Lewis base as a co-catalyst during polymerization of a conjugated diene compound, the content of the structural unit (X) in the polymer block (B) and the contents of 3,4-bonds and 1,2-bonds can be increased. Examples of the Lewis base include ethers such as dimethyl ether, diethyl ether, tetrahydrofuran, and 2,2-di(2-tetrahydrofuryl)propane (DTHFP); glycol ethers such as ethylene glycol dimethyl ether, diethylene glycol dimethyl ether, triethylene glycol dimethyl ether, and tetraethylene glycol dimethyl ether; amines such as triethylamine, N,N,N',N'-tetramethylenediamine, N,N,N',N'-tetramethylethylenediamine (TMEDA), and N-methylmorpholine; and metal salts such as sodium or potassium salts of aliphatic alcohols, such as sodium t-butylate, sodium t-amylate, and sodium isopentylate, or dialkylsodium cyclohexanolates, and sodium or potassium salts of alicyclic alcohols, such as sodium mentholate. These Lewis bases can be used alone or in combination of two or more.

[0081] The amount of the Lewis base added is determined by the extent to which the content of the structural unit (X) is controlled, and, when the polymer block (B) contains structural units derived from isoprene and / or butadiene, the extent to which the vinyl bond content of the isoprene units and / or butadiene units constituting the polymer block (B) is controlled. Therefore, although there is no strict limitation on the amount of the Lewis base added, it is preferable to use it in the range of preferably 0.1 to 1,000 mol, more preferably 1 to 100 mol, per gram atom of lithium contained in the alkyllithium compound or dilithium compound used as a polymerization initiator.

[0082] From the viewpoint of increasing the content of the structural unit (X), the average feed rate of the conjugated diene compound (hereinafter sometimes referred to as "average diene feed rate") is preferably 150 kg / h or less, more preferably 110 kg / h or less, and even more preferably 55 kg / h or less, per mole of active terminal, and may be 45 kg / h or less, 30 kg / h or less, 25 kg / h or less, or may be 22 kg / h or less. From the viewpoint of increasing productivity, the lower limit is preferably 1 kg / h or more, more preferably 3 kg / h or more, and even more preferably 5 kg / h or more, per mole of active terminal, and may be 7 kg / h or more, 10 kg / h or more, or 15 kg / h or more.

[0083] After carrying out the polymerization by the above-mentioned method, an active hydrogen compound such as an alcohol, a carboxylic acid, or water is added to terminate the polymerization reaction, thereby obtaining a block copolymer.

[0084] [Method for Producing a Hydrogenated Block Copolymer] The hydrogenated block copolymer according to component (III) can be obtained, for example, by hydrogenating the block copolymer obtained by the above-described production method. To obtain a modified hydrogenated product, the block copolymer may be modified by the method described below and then hydrogenated. When hydrogenating the block copolymer obtained by the above-described production method, a hydrogenation reaction (hydrogenation reaction) is carried out in an inert organic solvent in the presence of a hydrogenation catalyst. The hydrogenation reaction hydrogenates the carbon-carbon double bonds in the polymer block (B) of the block copolymer, resulting in a hydrogenated block copolymer. The hydrogenation reaction can be carried out at a hydrogen pressure of about 0.1 to 20 MPa, preferably 0.5 to 15 MPa, more preferably 0.5 to 5 MPa, at a reaction temperature of about 20 to 250°C, preferably 50 to 180°C, more preferably 70 to 180°C, for a reaction time of typically about 0.1 to 100 hours, preferably 1 to 50 hours. Examples of the hydrogenation catalyst include Raney nickel, heterogeneous catalysts in which a metal such as Pt, Pd, Ru, Rh, or Ni is supported on a simple substance such as carbon, alumina, or diatomaceous earth, Ziegler catalysts comprising a combination of a transition metal compound with an alkylaluminum compound, an alkyllithium compound, or the like, and metallocene catalysts. Among these, from the viewpoint of easily suppressing nuclear hydrogenation of aromatic rings, Ziegler catalysts are preferred, more preferably Ziegler catalysts comprising a combination of a transition metal compound with an alkylaluminum compound, and even more preferably Ziegler catalysts comprising a combination of a nickel compound with an alkylaluminum compound (Al / Ni-based Ziegler catalysts).

[0085] The hydrogenated block copolymer thus obtained can be obtained, for example, by pouring the polymerization reaction liquid into methanol or the like to coagulate it, followed by drying under heat or reduced pressure, or by pouring the polymerization reaction liquid into hot water together with steam to remove the solvent by azeotropy (so-called steam stripping), followed by drying under heat or reduced pressure.

[0086] [Method for producing modified block copolymer and hydrogenated product thereof] The modified block copolymer according to component (III) or hydrogenated product thereof can be produced, for example, by introducing the above-mentioned functional group into the block copolymer or hydrogenated product thereof. When the modified hydrogenated product is modified by a radical reaction, it is preferable, from the viewpoint of reaction control, to produce the modified hydrogenated product by hydrogenating the block copolymer to form a hydrogenated block copolymer and then introducing a specific functional group.

[0087] The reaction of modifying a block copolymer or hydrogenated block copolymer by introducing the functional group described above (hereinafter, sometimes referred to as the "modification reaction") can be carried out by a known method. The modification reaction can be carried out, for example, by dissolving the block copolymer or hydrogenated block copolymer in an organic solvent, adding various modifiers capable of adding the functional group described above, and carrying out the reaction at preferably about 50 to 300°C for about 0.5 to 10 hours. The modification reaction can also be carried out, for example, by moltenizing the block copolymer or hydrogenated block copolymer using an extruder or the like without using a solvent, and then adding various modifiers. In this case, the modification reaction temperature is preferably from the melting point of the block copolymer or hydrogenated block copolymer to 400°C or less, more preferably 90 to 350°C, and even more preferably 100 to 300°C, and the reaction time is preferably about 0.5 to 10 minutes. When carrying out the modification reaction in a molten state, it is preferable to add a radical initiator, and an antioxidant may also be added to suppress side reactions.

[0088] In the method for producing a modified block copolymer or a modified hydrogenated product, the modification reaction is preferably carried out by the latter method of modification in a molten state, from the viewpoint of improving workability, vibration damping properties, and thermal stability. That is, a preferred embodiment of the method for producing a modified block copolymer or a modified hydrogenated product further comprises a step of introducing one or more functional groups selected from an alkoxysilyl group, a carboxy group, an amino group, a hydroxy group, an epoxy group, and a group derived from an acid anhydride into the block copolymer or hydrogenated block copolymer in a molten state using a radical initiator.

[0089] The modifying agent capable of adding the functional group is preferably at least one selected from the group consisting of dimethyldiethoxysilane, tetramethoxysilane, tetraethoxysilane, 3-aminopropyltriethoxysilane, vinyltrimethoxysilane, vinyltriethoxysilane, hydroxymethyltriethoxysilane, vinylbenzyldiethylamine, vinylbenzyldimethylamine, 1-glycidyl-4-(2-pyridyl)piperazine, 1-glycidyl-4-phenylpiperazine, 1-glycidyl-4-methylpiperazine, 1-glycidyl-4-methylhomopiperazine, 1-glycidylhexamethyleneimine, and tetraglycidyl-1,3-bisaminomethylcyclohexane. Furthermore, unsaturated carboxylic acid anhydrides such as maleic anhydride, citraconic anhydride, 2,3-dimethylmaleic anhydride, and itaconic anhydride can also be used as the modifying agent. Furthermore, a modifying agent capable of adding the functional group may be adopted from among the modifying agents described in JP 2011-132298 A. The modifying agents may be used alone or in combination of two or more.

[0090] The amount of the modifier to be added may be determined appropriately depending on the content of the functional group in the modified block copolymer or modified hydrogenated product described above so as to achieve a desired content of the functional group. The amount of the modifier to be added is preferably 0.01 to 10 parts by mass, more preferably 0.01 to 5 parts by mass, even more preferably 0.01 to 3 parts by mass, and still more preferably 0.05 to 2 parts by mass, relative to 100 parts by mass of the block copolymer or hydrogenated block copolymer.

[0091] The radical initiator may be an organic peroxide or organic perester, such as dialkyl peroxides, diacyl peroxides, peroxyesters, peroxyketals, dialkyl peroxides, or hydroperoxides. Alternatively, azo compounds, such as azobisisobutyronitrile and dimethylazoisobutyrate, may also be used. Among the radical initiators, organic peroxides are preferred, and dialkyl peroxides are more preferred. The amount of radical initiator added may be determined appropriately depending on the combination of the block copolymer or hydrogenated block copolymer and the modifier. The amount of radical initiator added is preferably 0.01 to 10 parts by mass, more preferably 0.01 to 5 parts by mass, even more preferably 0.01 to 3 parts by mass, and even more preferably 0.05 to 2 parts by mass, per 100 parts by mass of the block copolymer or hydrogenated block copolymer.

[0092] The content of component (III) in the grease composition can be adjusted appropriately depending on the intended use of the resulting grease composition. For example, in one embodiment of the present invention, it is preferable that the content of component (III) in the grease composition is 0.5% by mass or more, based on 100% by mass of the total amount of the grease composition, from the viewpoint of more readily achieving the effects of the present invention. Furthermore, it is preferable that the content of component (III) is 20% by mass or less, based on 100% by mass of the total amount of the grease composition, from the viewpoint of more readily preventing the viscosity of the resulting grease composition from becoming unnecessarily high. From this viewpoint, in one embodiment of the present invention, the content of component (III) is preferably 0.5 to 20% by mass, more preferably 0.8 to 10% by mass, even more preferably 1 to 5% by mass, and even more preferably 1 to 4% by mass, based on 100% by mass of the total amount of the grease composition.

[0093] The total content of components (I), (II), and (III) in the grease composition can be adjusted as appropriate as long as it does not interfere with the objects and effects of the present invention. For example, in one embodiment of the present invention, from the viewpoint of more easily achieving the effects of the present invention, the total content of components (I), (II), and (III) in the grease composition is preferably 80 to 100% by mass, more preferably 85 to 100% by mass, even more preferably 90 to 100% by mass, and still more preferably 95 to 100% by mass, based on the total amount of the grease composition (100% by mass).

[0094] <Other Polymers> The grease composition of one embodiment of the present invention may contain other polymers (hereinafter also referred to as "other polymers") in addition to the above-described component (III), as long as the other polymers do not interfere with the objects and effects of the present invention. Examples of such other polymers include the block copolymers and hydrogenated products thereof in the above-described component (III) that do not contain the structural unit (X) and hydrogenated products thereof; polyolefins such as polyethylene and polypropylene (excluding the PAO used as component (I)); polyconjugated dienes such as polybutadiene, styrene-butadiene random copolymer, polyisoprene, butadiene-isoprene copolymer, polyfarnesene, butadiene-farnesene copolymer, and modified products thereof; polyisobutylene; and polymethacrylate. When the grease composition according to one embodiment of the present invention contains other polymers, from the viewpoint of facilitating the achievement of the effects of the present invention, the other polymers preferably include, among the block copolymers and hydrogenated products thereof described in component (III), block copolymers and hydrogenated products thereof that do not contain the structural unit (X), and more preferably, hydrogenated products of block copolymers described in component (III) that do not contain the structural unit (X). Among the hydrogenated block copolymers described in component (III), examples of hydrogenated products of block copolymers that do not contain the structural unit (X) include hydrogenated styrene-based thermoplastic elastomers. Examples of such hydrogenated styrene-based thermoplastic elastomers include hydrogenated block copolymers having a hydrogenated block portion formed from structural units derived from at least one selected from butadiene and isoprene (however, not all of the structural units need to be hydrogenated), and a polystyrene block portion. The hydrogenated block copolymer is not limited in terms of the bonding form of each block, and may be linear, branched, radial, or a combination of two or more of these. Among these, the bonding form of each polymer block is preferably linear, and examples thereof are the same as those described above in the section "Bonding form between polymer block (A) and polymer block (B)."In one embodiment of the present invention, the hydrogenated styrene-based thermoplastic elastomer, which is the other polymer, is preferably a diblock type, and more preferably at least one selected from the group consisting of a hydrogenated styrene-butadiene diblock copolymer and a hydrogenated styrene-isoprene diblock copolymer. Furthermore, among the hydrogenated block copolymers in component (III), the hydrogenated block copolymer not containing the structural unit (X) may be a modified hydrogenated product having a functional group, as described above in the section for component (III).

[0095] When the grease composition contains the other polymer, the content of the other polymer can be adjusted as appropriate as long as it does not interfere with the objects and effects of the present invention. For example, in one aspect of the present invention, the content of the other polymer in the grease composition is preferably 0.5 to 20 mass%, more preferably 0.8 to 10 mass%, and even more preferably 1 to 5 mass%, relative to the total amount (100 mass%) of the grease composition.

[0096] When the grease composition contains the other polymer, the total content of the components (I), (II), and (III), and the other polymer in the grease composition can be adjusted as appropriate as long as it does not interfere with the objects and effects of the present invention. For example, in one aspect of the present invention, from the viewpoint of more easily achieving the effects of the present invention, the total content of the components (I), (II), and (III), and the other polymer in the grease composition is preferably 80 to 100% by mass, more preferably 85 to 100% by mass, even more preferably 90 to 100% by mass, and still more preferably 95 to 100% by mass, based on the total amount of the grease composition (100% by mass).

[0097] <Other Components> The grease composition of one embodiment of the present invention may contain various additives known as grease additives as components other than the above-described components (hereinafter also referred to as "other components"), as long as the purpose and effects of the present invention are not impaired. The various additives are preferably at least one selected from the group consisting of solid particles, antioxidants, rust inhibitors, corrosion inhibitors, extreme pressure agents, lubricity improvers, thickeners, adhesion improvers, viscosity index improvers, friction reducers, antiwear agents, oiliness agents, dyes, color stabilizers, and base oil diffusion inhibitors. The solid particles are preferably solid lubricants. The antioxidant is preferably at least one selected from the group consisting of phenolic antioxidants and amine antioxidants. These various additives may be used alone or in combination of two or more.

[0098] <Tan δ Strength of Grease Composition> Furthermore, from the viewpoint of more easily achieving the effects of the present invention, the grease composition of one embodiment of the present invention has a tan δ strength value at 25°C and 50 Hz of preferably 0.63 or more, more preferably 0.65 or more, even more preferably 0.70 or more, still more preferably 0.75 or more, still more preferably 0.80 or more, still more preferably 0.90 or more, and still more preferably 1.00 or more. Furthermore, from the viewpoint of more easily achieving the effects of the present invention, the grease composition of one embodiment of the present invention has a tan δ strength value at 40°C and 50 Hz of preferably 0.55 or more, more preferably 0.58 or more, even more preferably 0.60 or more, still more preferably 0.65 or more, still more preferably 0.70 or more, and still more preferably 0.75 or more. Furthermore, from the viewpoint of more easily achieving the effects of the present invention, the grease composition of one embodiment of the present invention preferably has a tan δ intensity value at 60°C and 50 Hz of 0.45 or more, more preferably 0.46 or more, even more preferably 0.49 or more, and still more preferably 0.50 or more. The tan δ intensity values ​​at 25°C and 50 Hz, 40°C and 50 Hz, and 60°C and 50 Hz of the grease composition are each values ​​measured according to the method described in the Examples.

[0099] As described above, the grease composition is also useful for reducing noise, and is therefore preferably used for sound deadening. That is, in one aspect of the present invention, the grease composition is preferably a sound deadening grease composition. In this specification, "sound deadening" refers to the effect of reducing sound intensity or sound pressure level.

[0100] <Low-Temperature Properties of Grease Composition> Furthermore, by containing the component (III), the grease composition according to one embodiment of the present invention is likely to exhibit excellent low-temperature properties. Specifically, the grease composition has a smooth appearance even in a low-temperature environment of -20°C. Another effect is that a good starting torque at -20°C is easily obtained. In one embodiment of the present invention, the starting torque value of the grease composition at -20°C is preferably 230 mN·m or less, more preferably 180 mN·m or less, even more preferably 150 mN·m or less, still more preferably 130 mN·m or less, even more preferably 120 mN·m or less, still more preferably 110 mN·m or less, and even more preferably 100 mN·m or less. The starting torque value of the grease composition at -20°C is a value measured according to the method described in the Examples.

[0101] <Worked Penetration of Grease Composition> The worked penetration of the grease composition according to one embodiment of the present invention can be adjusted as appropriate depending on the intended use of the resulting grease composition. For example, in one embodiment of the present invention, the worked penetration of the grease composition is preferably 85 to 475, more preferably 130 to 430, even more preferably 175 to 385, still more preferably 220 to 340, and even more preferably 265 to 295. The worked penetration of the grease composition can be measured in more detail according to the method described in the Examples.

[0102] [Method for Producing Grease Composition] The method for producing the grease composition according to one embodiment of the present invention is not limited as long as it allows the grease composition to be obtained by sequentially or simultaneously blending at least the components (I) to (III). In one embodiment of the method for producing the grease composition, it is preferable to prepare a grease composition containing the components (I) to (III) by mixing a copolymer composition containing the components (I) and (III) with a thickener composition containing the components (I) and (II).

[0103] (Copolymer Composition) The copolymer composition contains the component (I) and the component (III). The component (I) and the component (III) are the same as the component (I) and the component (III) described above in the section on the grease composition, which is one embodiment of the present invention, and the preferred embodiments thereof are also the same. Therefore, detailed description here will be omitted. It is preferable to prepare the copolymer composition containing the component (I) and the component (III) in advance and mix it with the thickener composition described below. This prevents problems such as aggregation of the component (III) in the grease composition when blending the component (III) into the grease composition, making it easier to blend the component (III) into the grease composition.

[0104] The content of component (III) in the copolymer composition is preferably 1 to 40% by mass, more preferably 3 to 30% by mass, even more preferably 4 to 25% by mass, and still more preferably 5 to 20% by mass, based on 100% by mass of the total amount of the copolymer composition. The total content of components (I) and (III) in the copolymer composition is preferably 80 to 100% by mass, more preferably 85 to 100% by mass, even more preferably 90 to 100% by mass, and still more preferably 95 to 100% by mass, based on 100% by mass of the total amount of the copolymer composition.

[0105] Furthermore, when the grease composition according to one embodiment of the present invention further contains a polymer other than component (III), it is preferable that, for the same reasons as those described above, in one embodiment of the production method, the copolymer composition further contains a polymer other than component (III). The "other polymer" is the same as the "other polymer" described above in the section on the grease composition according to one embodiment of the present invention, and the preferred embodiments thereof are also the same. Therefore, a detailed description thereof will be omitted here. When the copolymer composition further contains the other polymer, the content of the other polymer in the copolymer composition is preferably 1 to 40 mass%, more preferably 3 to 30 mass%, even more preferably 4 to 25 mass%, and even more preferably 5 to 20 mass%, based on the total amount of the copolymer composition (100 mass%). When the copolymer composition further contains the other polymer, the total content of component (III) and the other polymer in the copolymer composition is preferably 1 to 40 mass%, more preferably 3 to 30 mass%, and even more preferably 5 to 25 mass%, based on the total amount of the copolymer composition (100 mass%). Furthermore, when the copolymer composition further contains the other polymer, the total content of the component (I), the component (III), and the other polymer in the copolymer composition is preferably 80 to 100 mass%, more preferably 85 to 100 mass%, even more preferably 90 to 100 mass%, and still more preferably 95 to 100 mass%, based on 100 mass% of the total amount of the copolymer composition.

[0106] The method for mixing component (I) and component (III), as well as one or more selected from the other polymers and other additives for the grease composition that may be optionally blended, is not particularly limited as long as the resulting grease composition exhibits the effects of the present invention. For example, component (III), as well as one or more selected from the other polymers and other additives for the grease composition that may be optionally blended, may be added to component (I), and the mixture may be stirred and mixed using a stirring blade, or a dispersion treatment may be performed using a disperser. The mixture may be heated during the mixing treatment. The temperature during the mixing is not particularly limited as long as the components can be mixed and the effects of the present invention can be exhibited. For example, the temperature is preferably 100 to 200°C, more preferably 120 to 180°C, and even more preferably 130 to 170°C. The mixing may also be performed under a nitrogen atmosphere.

[0107] Furthermore, one embodiment of the method for producing the grease composition may include a step of mixing the component (I) and the component (III), as well as one or more selected from the other polymers and other additives for the grease composition that may be blended as necessary, and then cooling the obtained copolymer composition to a temperature of, for example, less than 100°C.

[0108] (Thickener Composition) The thickener composition contains the component (I) and the component (II). The components (I) and (II) are the same as the components (I) and (II) described above in the section on the grease composition, which is an embodiment of the present invention, and preferred embodiments thereof are also the same. Therefore, detailed description thereof will be omitted here. As described above in the section on component (II) of the grease composition, it is preferable to prepare the thickener composition by synthesizing component (II) by reacting compounds serving as raw materials for component (II) in component (I). One embodiment of the method for producing the grease composition may include a step of cooling the thickener composition obtained by blending the components (I) and (II) and one or more optional additives for the grease composition to a temperature below 100°C.

[0109] The content of component (II) in the thickener composition is preferably 1 to 45% by mass, more preferably 2 to 35% by mass, even more preferably 3 to 25% by mass, still more preferably 4 to 20% by mass, and even more preferably 5 to 15% by mass, based on 100% by mass of the total amount of the thickener composition. The content of component (II) in the thickener composition can be measured in more detail according to the method described in the Examples.

[0110] (Mixing of Copolymer Composition and Thickener Composition) The method for mixing the copolymer composition and the thickener composition is not particularly limited as long as the resulting grease composition exhibits the effects of the present invention. For example, they can be mixed by mechanical stirring or kneading using a stirrer, roll, disperser, or the like. Furthermore, during the mixing process, the components may be mixed at room temperature (25°C) or may be heated and mixed. The temperature during heating is not particularly limited as long as the components can be mixed and the effects of the present invention can be exhibited. For example, the temperature is preferably 50 to 100°C, more preferably 60 to 95°C, and even more preferably 75 to 95°C. One embodiment of the method for producing the grease composition may include a step of cooling the grease composition obtained by mixing the copolymer composition and the thickener composition to a temperature below 100°C. Furthermore, after the cooling treatment step, a step of performing a milling treatment using a roll mill or the like may be further included, and further, a degassing treatment step in a degassing tank, a foreign matter removal step of removing foreign matter by passing the mixture through a mesh or the like may be included.

[0111] [Sliding member] A sliding member according to one embodiment of the present invention has the grease composition according to the above-described embodiment of the present invention. The sliding member is a sliding member having the grease composition on its sliding surface, and the sliding surface slides in the presence of the grease composition. The sliding member is preferably one whose sliding surface is coated with the grease composition.

[0112] The sliding member preferably contains at least one selected from metal and resin. That is, the material of the sliding member is preferably at least one selected from metal and resin. The sliding member may be a metal sliding member, a resin sliding member such as plastic or rubber, or a sliding member manufactured using both metal and resin.

[0113] The sliding member is not particularly limited as long as it is used by applying the grease composition to the sliding surface, and examples thereof include door panels, instrument panels, door locks, gears, outboard joints, inboard joints, universal joints, flexible joints, belt tensioners, fixing belts, pressure belts, pads, timing belts, conveyor belts, body seals for sunroofs, glass runs, weather strips, oil seals, packings, wiper blades, doctor blades, charging rollers, developing rollers, toner supply rollers, transfer rollers, heat rollers, pressure rollers, cleaning blades, paper feed rollers, conveying rollers, Examples include feed rollers, doctor blades, intermediate transfer belts, intermediate transfer drums, heat belts, solenoid valves, electric valves, crankshafts, compressor shafts, slide bearings, gears, oil pump gears, pistons, piston rings, piston pins, gaskets, door locks, guide rails, seat belt buckles, brake pads, brake pad clips, brake shims, brake insulators, hinges, screws, pressure pads, air cylinders, electric cylinders, electric actuators, and other sliding members for automobiles, copiers, printers, and industrial machinery (including semiconductor manufacturing equipment and light emitting device / display manufacturing equipment).

[0114] Furthermore, a preferred embodiment of the sliding member is a rotating sliding member. Therefore, the grease composition is also suitable as a grease composition for a rotating sliding member that performs rotational motion. The rotating sliding member is not particularly limited as long as it is accompanied by rotational motion, but is preferably at least one member selected from the group consisting of a bearing, a gear, a rotary shaft, a belt, a heat roller, and a steering roller.

[0115] The application of the sliding member is not particularly limited, and it can be used in, for example, home appliances, ships, railways, aircraft, machinery (including industrial production equipment), structures, automobile repair, automobiles, construction, building materials, textiles, leather, stationery, woodworking, furniture, miscellaneous goods, steel plates, cans, electronic substrates, electronic components, printing, and the like. Among these, the sliding member is useful for applications in automobiles and industrial machinery. That is, the sliding member is preferably an automobile part or an industrial machinery part. Similarly, the grease composition according to one embodiment of the present invention can be suitably used for automobiles and industrial machinery. Furthermore, as described above, the grease composition according to one embodiment of the present invention is also useful for reducing noise, and therefore can be suitably used, for example, in mechanical devices or drive devices equipped with motors, and more specifically, can be suitably used in motor parts. Therefore, in one embodiment of the present invention, the sliding member is more preferably a motor part.

[0116] [Copolymer for Grease Composition] The copolymer for a grease composition, which is one embodiment of the present invention, is a block copolymer or a hydrogenated product thereof, which contains a polymer block (A) and a polymer block (B), wherein the polymer block (A) contains, as a main structural unit, a structural unit (S) derived from an aromatic vinyl compound, and the polymer block (B) contains, as a main structural unit, a structural unit (T) derived from a conjugated diene compound, and also contains a structural unit (X) represented by the following formula (X):

[0117]

[0118] In the formula (X), R １ ~R ３ are each independently a hydrogen atom or a hydrocarbon group having 1 to 11 carbon atoms. When the polymer block (B) contains two or more structural units (X), the plurality of R １ may be the same or different, and there are multiple R ２ may be the same or different, and there are multiple R ３may be the same or different. The copolymer for a grease composition, which is one embodiment of the present invention, is the same as the component (III) described above in the section on the grease composition, which is one embodiment of the present invention, and the preferred embodiments thereof are also the same. Therefore, a detailed description thereof will be omitted here.

[0119] Next, the present invention will be explained in more detail with reference to examples, but the present invention is not limited to these examples in any way.

[0120] Each component used in the examples and comparative examples will be explained below together with its abbreviation.

[0121] <Block copolymer, hydrogenated product, and modified hydrogenated product> The methods for evaluating the physical properties of the block copolymer, hydrogenated product, or modified hydrogenated product obtained in the production examples described later are as follows. (1) Content of polymer block (A) The block copolymer before hydrogenation was dissolved in CDCl ３ Dissolve in １ H-NMR measurement was performed [apparatus: "AVANCE 400 Nanobay" (manufactured by Bruker), sample concentration: 50 mg / 1 mL, measurement temperature: 30°C, number of accumulations: 1,024], and the content of polymer block (A) was calculated from the ratio of the peak intensity derived from styrene to the peak intensity derived from diene.

[0122] (2) Weight-average molecular weight (Mw) The weight-average molecular weight (Mw) of the polymer blocks (A) and (B), and the block copolymer or hydrogenated product, in terms of polystyrene, was determined by gel permeation chromatography (GPC) measurement under the following conditions. (GPC measurement device and measurement conditions) Device: GPC device "HLC-8020" (manufactured by Tosoh Corporation) Separation column: "TSKgel (registered trademark) guardcolumn Super HZ-L" (1 column) and "TSKgel (registered trademark) Super HZ4000" (2 columns) manufactured by Tosoh Corporation were connected in series in this order from the upstream side. Eluent: tetrahydrofuran Eluent flow rate: 0.7 mL / min Sample concentration: 5 mg / 10 mL Column temperature: 40°C Detector: refractive index (RI) detector Calibration curve: prepared using standard polystyrene

[0123] (3) Iodine Value <E> g of the block copolymer, hydrogenated product, or modified hydrogenated product was weighed out and diluted with 100 mL of chloroform. Next, 20.0 mL of Wiess's reagent (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd., 0.1 mol / L iodine chloride / acetic acid solution) was added, the mixture was shaken well, and the mixture was left for 30 minutes to allow the reaction to proceed. 20 mL of 10% by mass potassium iodide aqueous solution was added, followed by 100 mL of water and stirring. Then, 0.1 N sodium thiosulfate aqueous solution (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.) was gradually added dropwise until the solution became transparent (drop volume <F> mL). Next, the blank drop volume (drop volume <G> mL) was determined in the same manner, except that no sample was added. The iodine value of the block copolymer, hydrogenated product, or modified hydrogenated product was calculated using the above <E>, <F>, and <G> according to the following formula: Iodine value (g / 100g)=(<G>-<F>)×1.269 / <E> wherein <E> is determined as follows in accordance with JIS K 0070:1992. If the iodine value is less than 3, <E> is 3.0g or more and less than 5.0g. If the iodine value is 3 or more and less than 10, <E> is 2.5g or more and less than 3.0g. If the iodine value is 10 or more and less than 30, <E> is 0.60g or more and less than 2.5g. If the iodine value is 30 or more and less than 50, <E> is 0.40g or more and less than 0.60g. If the iodine value is 50 or more and less than 100, <E> is 0.20g or more and less than 0.30g. If the iodine value is 100 or more and less than 150, <E> is 0.12g or more and less than 0.20g. If the iodine value is 150 or more and less than 200, <E> is 0.10g or more and less than 0.15g. If the iodine value is 200 or more, <E> is 0.10g or more and less than 0.12g. Here, the <E> amount was selected after estimating an approximate iodine value in advance based on information such as the raw materials of the block copolymer, hydrogenated product, or modified hydrogenated product to be weighed, production conditions, measurement results of weight-average molecular weight, various NMR measurement results, etc. Furthermore, if there was a discrepancy between the iodine value actually calculated by the method based on the estimated iodine value and the <E> amount corresponding to the estimated value and the estimated iodine value, the iodine value was re-weighed within the range of the <E> amount specified in the JIS based on the iodine value obtained by actual measurement, and the iodine value was measured again.Then, the iodine value when the iodine value calculated by actual measurement finally coincided with the range of the weighed value <E> specified in the JIS was adopted as the iodine value of the block copolymer, hydrogenated product, or modified hydrogenated product.

[0124] (4) Hydrogenation rate in polymer block (B) The hydrogenated block copolymer was dissolved in CDCl ３ Dissolve in １ H-NMR measurement was performed [apparatus: "AVANCE 400 Nanobay" (manufactured by Bruker), sample concentration: 50 mg / 1 mL, measurement temperature: 30°C, number of accumulations: 1,024]. The hydrogenation rate was calculated from the ratio of the peak area derived from one or more residual olefins selected from isoprene and butadiene to the peak area derived from one or more olefins selected from ethylene, propylene, and butylene.

[0125] (5) Amount of vinyl bond in polymer block (B) The block copolymer before hydrogenation was dissolved in CDCl ３ Dissolve in １ H-NMR measurement was performed [apparatus: "AVANCE 400 Nanobay" (manufactured by Bruker), sample concentration: 50 mg / 1 mL, measurement temperature: 30°C, number of accumulations: 1,024]. The vinyl bond content (total proportion of the content of 3,4-bond units and 1,2-bond units) was calculated from the ratio of the total peak area of ​​structural units derived from one or more selected from isoprene and butadiene to the peak area corresponding to the 3,4-bond units and 1,2-bond units in the isoprene structural units, the 1,2-bond units in the butadiene structural units, or, in the case of structural units derived from a mixture of isoprene and butadiene, the peak area corresponding to each of the above bond units.

[0126] (6) Content of structural unit (X) in polymer block (B) 600 mg of block copolymer before hydrogenation and Cr(acac) ３ 40 mg of CDCl ３ Dissolve in 4 mL and quantify using a 10 mm NMR tube １３C-NMR measurement (pulse program: zgig, inverse gated 1H decoupling method) [apparatus: "AVANCE 400 Nanobay" (manufactured by Bruker), measurement temperature: 30°C, cumulative number: 100,000] was performed, and the contents of the structural units (X), (X1), and (X2) in the polymer block (B) were calculated by the following method. In Table 4, X, X1, and X2 represent the following structural units: X: structural unit (X) having a combination of the following substituents (i) to (vi) X1: structural unit (X1) having a combination of the following substituents (i) and (iv) X2: structural unit (X2) having a combination of the following substituents (ii), (iii), (v), and (vi) (i): R １ = hydrogen atom, R ２ = hydrogen atom, R ３ = hydrogen atom; (1,2Bd + Bd) (ii): R １ = hydrogen atom, R ２ = methyl group, R ３ = hydrogen atom; (1,2Bd + 1,2Ip) (iii): R １ = hydrogen atom, R ２ = hydrogen atom, R ３ = methyl group; (1,2Bd + 3,4Ip) (iv): R １ = methyl group, R ２ = hydrogen atom, R ３ = hydrogen atom; (1,2Ip+Bd) (v): R １ = methyl group, R ２ = methyl group, R ３ = hydrogen atom; (1,2Ip + 1,2Ip) (vi): R １ = methyl group, R ２ = hydrogen atom, R ３ = methyl group; (1,2Ip + 3,4Ip)

[0127] [Calculation Method] Each peak and the structure derived therefrom are shown in Table 1-1. If the integral values ​​of each peak are a to g, the integral values ​​of each structure are as shown in Table 1-2, and the contents of "X", "X1", and "X2" can be calculated by "(a + g - c) / (a + b + c - d + e / 2 + 2f)", "(g - c) / (a + b + c - d + e / 2 + 2f)", and "a / (a + b + c - d + e / 2 + 2f)", respectively. However, in Table 1-1, if a peak appearing at 110 ppm overlaps, it is counted as integral value b. Furthermore, in Table 1-1, if a peak appearing at 127 ppm overlaps, it is counted as integral value e, and if a peak appearing at 132 ppm overlaps, it is counted as integral value f.

[0128]

[0129] (7) １３ C-NMR peak area ratio (7-1) Block copolymer (unhydrogenated) The block copolymer of Production Example 5 was subjected to the above quantitative analysis. １３ C-NMR measurement [apparatus: "AVANCE 400 Nanobay" (manufactured by Bruker), sample concentration: 100 mg / 1 mL, measurement temperature: 30°C, number of accumulations: 100,000, solvent: CDCl ３ The peak area ratio [peak area at chemical shift values ​​of 107 ppm or more and less than 110 ppm] / [peak area at chemical shift values ​​of 110 ppm or more and 116 ppm or less] was calculated. (7-2) Hydrogenated Products (After Hydrogenation) The hydrogenated products or modified hydrogenated products of Production Examples 1, 2, 3, 4, 6, Comparative Production Example 1, and Reference Production Example 1 were subjected to the above quantitative analysis. １３ C-NMR measurement [apparatus: "AVANCE 400 Nanobay" (manufactured by Bruker), sample concentration: 100 mg / 1 mL, measurement temperature: 30°C, number of accumulations: 100,000, solvent: CDCl ３ ] was performed, and the peak area ratio [peak area of ​​chemical shift value of 50 ppm or more and 52 ppm or less] / [peak area of ​​chemical shift value of 43 ppm or more and 45 ppm or less] was calculated.

[0130] (8) Amount of Maleic Anhydride Modification 5 g of the modified hydrogenated product of Production Example 6 was dissolved in 180 ml of toluene, and then 20 ml of ethanol was added. The mixture was titrated with a 0.1 mol / L potassium hydroxide solution, and the amount of maleic anhydride modification was calculated using the following formula: Amount of maleic anhydride modification (phr) = Titration amount × 5.611 / Sample amount × 98 × 100 / 56.11 × 1,000

[0131] (9) tan δ peak-top temperature, peak-top strength, and maximum width of the temperature range where tan δ is 1.0 or greater. For the following measurements, a block copolymer or hydrogenated product was pressurized at 230°C and 10 MPa for 3 minutes to produce a 1.0 mm thick monolayer sheet. This monolayer sheet was cut into a disk shape and used as the test sheet. For the measurements, a strain-controlled dynamic viscoelasticity device "ARES-G2" (manufactured by TA Instruments Japan Co., Ltd.) with a disk diameter of 8 mm was used as a parallel plate oscillatory rheometer in accordance with JIS K 7244-10:2005. The gap between the two plates was completely filled with the test sheet, and the test sheet was subjected to vibration at a frequency of 1 Hz with a strain of 0.1% and heated from -70°C to 100°C at a constant rate of 3°C / min. The temperatures of the test sheet and disc were maintained until there was no change in the measured values ​​of shear loss modulus and shear storage modulus, and the peak top strength, which is the maximum value of the peak strength of tanδ, and the peak top temperature, which is the temperature at which this maximum value was reached, were determined. The maximum width of the temperature region where tanδ was 1.0 or more was also determined. In Reference Production Example 1, there was no temperature region where tanδ was 1.0 or more, so the maximum width of the temperature region was expressed as "0".

[0132] [Production Example 1] Production of hydrogenated product (H-TPE-1) A nitrogen-purged, dried pressure vessel was charged with 50 kg of cyclohexane as a solvent and 87 g of a 10.5% by mass cyclohexane solution of sec-butyllithium as an anionic polymerization initiator (effective amount of sec-butyllithium added: 9.1 g). After heating the pressure vessel to 50 ° C., 1.0 kg of styrene (1) was added and polymerized for 1 hour. At a vessel temperature of 40 ° C., 32 g of 2,2-di(2-tetrahydrofuryl)propane (DTHFP) was added as a Lewis base, and 14.64 kg of isoprene was added at the average diene feed rate shown in Table 2 over 5 hours, followed by polymerization for 2 hours. 1.0 kg of styrene (2) was then added and polymerized for 1 hour to obtain a reaction solution containing a polystyrene-polyisoprene-polystyrene triblock copolymer. A Ziegler hydrogenation catalyst formed from nickel octylate and trimethylaluminum was added to the reaction solution under a hydrogen atmosphere, and the reaction was carried out for 5 hours under conditions of a hydrogen pressure of 1 MPa and 80°C. After allowing the reaction solution to cool and release the pressure, the catalyst was removed by washing with water, and the solution was dried in a vacuum to obtain a hydrogenated product of polystyrene-polyisoprene-polystyrene triblock copolymer (hereinafter also referred to as "H-TPE-1"). It was confirmed that the structural unit (X) was contained in the obtained H-TPE-1. １３ The properties were confirmed by C-NMR measurement. The raw materials and their amounts used are shown in Table 2. The results of the physical property evaluation are shown in Table 4.

[0133] [Production Example 2] Production of hydrogenated product (H-TPE-2) A hydrogenated block copolymer (hereinafter also referred to as "H-TPE-2") was produced in the same manner as in Production Example 1, except that the components, their amounts, and reaction conditions were changed as shown in Table 2. It was confirmed that the resulting H-TPE-2 contained the structural unit (X). １３ The properties were confirmed by C-NMR measurement. The results of the physical property evaluation are shown in Table 4.

[0134] [Production Example 3] Production of hydrogenated product (H-TPE-3) A hydrogenated block copolymer (hereinafter also referred to as "H-TPE-3") was produced in the same manner as in Production Example 1, except that the components, their amounts, and reaction conditions were changed as shown in Table 2. It was confirmed that the structural unit (X) was contained in the obtained H-TPE-3. １３ The properties were confirmed by C-NMR measurement. The results of the physical property evaluation are shown in Table 4.

[0135] [Production Example 4] Production of hydrogenated product (H-TPE-4) A hydrogenated block copolymer (hereinafter also referred to as "H-TPE-4") was produced in the same manner as in Production Example 1, except that the components, their amounts, and reaction conditions were changed as shown in Table 2. It was confirmed that the structural unit (X) was contained in the obtained H-TPE-4. １３ The properties were confirmed by C-NMR measurement. The results of the physical property evaluation are shown in Table 4.

[0136] [Production Example 5] Production of Block Copolymer (TPE-5) A nitrogen-purged, dried pressure vessel was charged with 50 kg of cyclohexane as a solvent and 101 g of a 10.5% by mass cyclohexane solution of sec-butyllithium as an anionic polymerization initiator (effective amount of sec-butyllithium added: 10.6 g). After heating the pressure vessel to 50 ° C., 1.7 kg of styrene (1) was added and polymerized for 1 hour. At a vessel temperature of 40 ° C., 65 g of N,N,N',N'-tetramethylethylenediamine (TMEDA) was added as a Lewis base, and 13.3 kg of isoprene was added at the average diene feed rate shown in Table 2 over 5 hours, followed by polymerization for 2 hours. 1.7 kg of styrene (2) was then added and polymerized for 1 hour, yielding a reaction solution containing a polystyrene-polyisoprene-polystyrene triblock copolymer. The polymerization reaction was terminated by adding 10 mL of methanol to the resulting reaction solution. The resulting reaction solution was washed with water and then reprecipitated in a large amount of methanol to obtain a polystyrene-polyisoprene-polystyrene triblock copolymer (hereinafter also referred to as "TPE-5"). It was confirmed that the resulting TPE-5 contained the structural unit (X). １３The properties were confirmed by C-NMR measurement. The raw materials and their amounts used are shown in Table 2. The results of the physical property evaluation are shown in Table 4.

[0137] [Production Example 6] Production of modified hydrogenated product (MH-TPE-6) Using a twin-screw extruder "ZSK26mc" (26 mmΦ, L / D=56) manufactured by Coperion Co., Ltd. under the following extrusion conditions, 10 kg of the hydrogenated product (H-TPE-1) obtained in Production Example 1 above was blended and melted, and 0.01 kg of 2,5-dimethyl-2,5-di(t-butylperoxy)hexane ("Perhexa (registered trademark) 25B-40" manufactured by NOF Corporation) as a radical initiator and 0.1 kg of maleic anhydride as a modifier were blended to carry out a modification reaction, thereby obtaining a modified hydrogenated product (hereinafter also referred to as "MH-TPE-6"). It was confirmed that the resulting MH-TPE-6 contained the structural unit (X). １３ The properties were confirmed by C-NMR measurement. Table 3 shows the raw materials and their amounts used. Table 4 shows the results of the physical property evaluation. <Extrusion conditions> Twin-screw extruder settings: Resin feed port 40°C, cylinder inlet 150°C, adapter 210°C, die 210°C Screw rotation speed: 300 rpm

[0138] Comparative Production Example 1 Production of Hydrogenated Product (H-TPE-C1) A hydrogenated product of a block copolymer (hereinafter also referred to as "H-TPE-C1") was produced in the same manner as in Production Example 1, except that the components, their amounts used, and the reaction conditions were changed as shown in Table 2. The results of the physical property evaluation are shown in Table 4.

[0139] Reference Production Example 1 Production of Hydrogenated Product (H-TPE-R1) A hydrogenated product of a block copolymer (hereinafter also referred to as "H-TPE-R1") was produced in the same manner as in Production Example 1, except that the components, their amounts used, and the reaction conditions were changed as shown in Table 2. The results of the physical property evaluation are shown in Table 4.

[0140]

[0141]

[0142]

[0143] <Thickener Composition> (10) Thickener Content in Thickener Composition 30 mg of the thickener composition was dissolved in 5 g of hexane to obtain a solution. Next, the weight of a PTFE syringe filter (pore size: 0.45 μm) was measured. The filter weight was designated as <F1> mg. Next, the solution was completely filtered using the filter, and the filtered filter was dried under reduced pressure at 80° C. for 3 hours. The filter weight after drying was designated as <F2> mg. The thickener content in the thickener composition is calculated using the following formula: Thickener content (mass%) = (<F2> - <F1>) ÷ 30 × 100. The <F1> value of the thickener composition used in the examples was 780 mg, and the <F2> value was 783 mg.

[0144] <Grease Composition> The methods for evaluating the physical properties of the grease compositions obtained in the examples and comparative examples described later are as follows. (11) Tan δ Strength at 25°C, 40°C, and 60°C For the measurements, a strain-controlled dynamic viscoelasticity device "ARES-G2" (manufactured by TA Instruments Japan Co., Ltd.) with a disk diameter of 25 mm was used as a parallel plate vibration rheometer. The grease composition was completely filled between two flat plates, and vibrations were applied to the grease composition at a frequency of 50 Hz with a strain of 0.5%, and the tan δ strengths at 25°C, 40°C, and 60°C were determined.

[0145] (12) Sound Pressure Level A test specimen was prepared by applying the grease composition to a steel plate (length 300 mm x width 300 mm x thickness 3 mm) in a size of 40 mm length x 40 mm width x 5 mm thickness. A steel ball (diameter 15.5 mm) was dropped onto the grease composition of the test specimen from a height of 100 mm from the surface of the steel plate, and the sound pressure level upon impact with the test specimen was measured with a microphone installed at a height of 200 mm from the surface of the steel plate. The following measuring device was used as the microphone. Note that, in the tables below, cases where the appearance of the grease composition was not smooth and the grease composition could not be applied were indicated as "F". (Sound Pressure Level Measuring Device) Device: "SOUND LEVEL METER, NL-42A" manufactured by Rion Co., Ltd.

[0146] (13) Worked Penetration The worked penetration of the grease composition was measured by a method in accordance with JIS K 2220:2013, item 7, "7.5 Procedure for worked penetration test using a standard cone."

[0147] (14) Starting Torque and Appearance at -20°C The starting torque of the grease composition at -20°C was measured according to item 18 of JIS K 2220:2013. In addition, in the tables below, if the appearance of the grease composition at the time of measurement was smooth, it was marked with "A", and if it was not smooth, it was marked with "F".

[0148] [Example 1] 10 parts by mass of the hydrogenated product (H-TPE-1) produced in Production Example 1, base oil-1 ("SAMIC (registered trademark) G-150" manufactured by Sanwa Chemical Industry Co., Ltd., Group II mineral oil, kinematic viscosity at 40°C: 29 mm ２ 90 parts by mass of a grease composition (100%) containing 10% PEG / s of grease was mixed under nitrogen at 150°C for 2 hours using a Three-One motor. The mixture was then cooled to room temperature to prepare a copolymer composition. 20 parts by mass of the obtained copolymer composition and 80 parts by mass of a lithium grease thickener composition ("Otokomae Monotaro (registered trademark) Lithium Grease" manufactured by MonotaRO Corporation, consistency number: No. 2, thickener: lithium soap, thickener content: 10% by mass; base oil: mineral oil, base oil content: 85 to 90% by mass) were mixed using a stainless steel spatula at 80 to 90°C for 30 minutes. The mixture was then cooled to room temperature to prepare Grease Composition 1. The composition of Grease Composition 1 is shown in Table 5. The tan δ intensity of the obtained Grease Composition 1 at 25°C, 40°C, and 60°C was measured according to the method described above. The results are shown in Table 5. The sound pressure level of the obtained Grease Composition 1 was measured according to the method described above. The results are shown in Table 5. The worked penetration of the resulting grease composition 1 was measured according to the method described above. The results are shown in Table 5. The starting torque of the resulting grease composition 1 at -20°C was measured according to the method described above. The appearance of the grease composition 1 was also observed during the measurement. The results are shown in Table 5.

[0149] Examples 2 to 6, Comparative Example 1 Grease compositions 2 to 6 and grease composition C1 were produced in the same manner as in Example 1, except that the hydrogenated product (H-TPE-1) produced in Production Example 1 was replaced with the block copolymer, hydrogenated product, or modified hydrogenated product (H-TPE-2, H-TPE-3, H-TPE-4, TPE-5, MH-TPE-6, H-TPE-C1) produced in Production Examples 2 to 6 and Comparative Production Example 1. The compositions of grease compositions 2 to 6 and grease composition C1 are shown in Table 5. For the resulting grease compositions 2 to 6 and grease composition C1, the tan δ intensity, sound pressure level, worked penetration at 25°C, 40°C, and 60°C, as well as the starting torque at -20°C were measured according to the methods described above. The appearance of grease compositions 2 to 6 and grease composition C1 was also observed during the starting torque measurement. The results are shown in Table 5.

[0150] [Example 7] 20 parts by mass of the hydrogenated product (H-TPE-1) produced in Production Example 1, base oil-1 ("SAMIC (registered trademark) G-150" manufactured by Sanwa Chemical Industry Co., Ltd., Group II mineral oil, kinematic viscosity at 40°C: 29 mm ２ 80 parts by mass of grease composition 7 (100%) and 80 parts by mass of grease composition 7 (100%) were mixed under nitrogen at 150°C for 2 hours using a Three-One Motor manufactured by Shinto Chemical Industry Co., Ltd. Grease composition 7 was prepared in the same manner as in Example 1. The composition of grease composition 7 is shown in Table 5. The tan δ intensity, sound pressure level, worked penetration at 25°C, 40°C, and 60°C, and the starting torque at -20°C were measured for the resulting grease composition 7 according to the methods described above. The appearance of grease composition 7 was also observed during the starting torque measurement. The results are shown in Table 5.

[0151] [Example 8] 10 parts by mass of the hydrogenated product (H-TPE-1) produced in Production Example 1, 10 parts by mass of the hydrogenated product (H-TPE-R1) produced in Reference Production Example 1, and base oil-1 ("SAMIC (registered trademark) G-150" manufactured by Sanwa Chemical Industry Co., Ltd., Group II mineral oil, kinematic viscosity at 40°C: 29 mm ２80 parts by mass of grease composition 8 (100%) and 80 parts by mass of grease composition 8 (100%) were mixed under nitrogen at 150°C for 2 hours using a Three-One Motor manufactured by Shinto Chemical Industry Co., Ltd. Grease composition 8 was prepared in the same manner as in Example 1. The composition of grease composition 8 is shown in Table 6. The tan δ intensity, sound pressure level, worked penetration at 25°C, 40°C, and 60°C, and the starting torque at -20°C were measured for the resulting grease composition 8 according to the methods described above. The appearance of grease composition 8 was also observed during the starting torque measurement. The results are shown in Table 6.

[0152] Comparative Example 2 Grease composition C2 was produced in the same manner as in Example 8, except that the hydrogenated product (H-TPE-1) produced in Production Example 1 was replaced with the hydrogenated product (H-TPE-C1) produced in Comparative Production Example 1. The composition of grease composition C2 is shown in Table 6. The tan δ intensity, sound pressure level, worked penetration, and starting torque at -20°C of the resulting grease composition C2 were measured according to the methods described above. The appearance of grease composition C2 was also observed during the starting torque measurement. The results are shown in Table 6.

[0153] Example 9 Grease composition 9 was produced in the same manner as in Example 1, except that the lithium grease ("Otokomae Monotaro (registered trademark) Lithium Grease" manufactured by MonotaRO Corporation, consistency number: No. 2, thickener: lithium soap, base oil: mineral oil) was changed to urea grease ("Excellite (registered trademark)" manufactured by Kyodo Yushi Co., Ltd., consistency number: No. 2, thickener: urea compound, thickener content: 10 mass %; base oil: mineral oil, base oil content: 85 to 90 mass %). The composition of grease composition 9 is shown in Table 7. For the obtained grease composition 9, the tan δ intensity, sound pressure level, and worked penetration at 25°C, 40°C, and 60°C, as well as the starting torque at -20°C, were measured according to the methods described above. The appearance of grease composition 9 was also observed during the starting torque measurement. The results are shown in Table 7.

[0154] Comparative Example 3 Grease composition C3 was produced in the same manner as in Example 9, except that the hydrogenated product (H-TPE-1) produced in Production Example 1 was replaced with the hydrogenated product (H-TPE-C1) produced in Comparative Production Example 1. The composition of grease composition C3 is shown in Table 7. The tan δ intensity, sound pressure level, worked penetration, and starting torque at -20°C of the resulting grease composition C3 were measured according to the methods described above. The appearance of grease composition C3 was also observed during the starting torque measurement. The results are shown in Table 7.

[0155] Example 10: Base oil-1 (Sanwa Chemical Industry Co., Ltd., "Samic (registered trademark) G-150", Group II mineral oil, kinematic viscosity at 40°C: 29 mm ２ Grease composition 10 was produced in the same manner as in Example 1, except that base oil-1 (base oil 1 / s) was changed to base oil-2 (Durasyn (registered trademark) 166 (Group IV PAO) manufactured by INEOS Corporation). The composition of grease composition 10 is shown in Table 8. The tan δ intensity, sound pressure level, worked penetration, and starting torque at -20°C of the obtained grease composition 10 were measured according to the above-mentioned methods. The appearance of grease composition 10 was also observed during the starting torque measurement. The results are shown in Table 8.

[0156] Comparative Example 4 Grease composition C4 was produced in the same manner as in Example 10, except that the hydrogenated product (H-TPE-1) produced in Production Example 1 was replaced with the hydrogenated product (H-TPE-C1) produced in Comparative Production Example 1. The composition of grease composition C4 is shown in Table 8. The tan δ intensity, sound pressure level, worked penetration, and starting torque at -20°C of the resulting grease composition C4 were measured according to the methods described above. The appearance of grease composition C4 was also observed during the starting torque measurement. The results are shown in Table 8.

[0157]

[0158] Table 5 reveals the following. <Thickener: Lithium soap, Base oil: Mineral oil> The grease compositions of Examples 1 to 7 had higher tan δ strengths at 25°C, 40°C, and 60°C than the grease composition of Comparative Example 1, demonstrating that these grease compositions are capable of reducing vibration and noise. Furthermore, the grease compositions of Examples 1 to 7 had a smoother appearance even at -20°C than the grease composition of Comparative Example 1, demonstrating superior low-temperature properties. In particular, the grease compositions of Examples 1, 3, and 6 had lower starting torque at -20°C than the grease composition of Comparative Example 1, demonstrating superior low-temperature properties. Furthermore, the grease compositions of Examples 1, 3 to 5, and 7 maintained the consistency number 2 (worked consistency: 265 to 295) of the thickener composition.

[0159]

[0160] The following can be seen from Table 6. <Combined system of component (III) and other polymer; thickener: lithium soap, base oil: mineral oil> The grease composition of Example 8 had higher tan δ strength at 25°C, 40°C, and 60°C than the grease composition of Comparative Example 2, and was found to be a grease composition that can reduce vibration and noise. Furthermore, the grease composition of Example 8 had lower starting torque at -20°C than the grease composition of Comparative Example 2, and was excellent in low-temperature properties.

[0161]

[0162] The following can be seen from Table 7. <Thickener: Urea compound, Base oil: Mineral oil> The grease composition of Example 9 had higher tan δ strength at 25°C, 40°C, and 60°C than the grease composition of Comparative Example 3, and was found to be a grease composition that can reduce vibration and noise. Furthermore, the grease composition of Example 9 had lower starting torque at -20°C than the grease composition of Comparative Example 3, and was excellent in low-temperature properties.

[0163]

[0164] The following can be seen from Table 8. <Thickener: lithium soap, base oil: synthetic oil (PAO)> The grease composition of Example 10 had higher tan δ strength at 25°C, 40°C, and 60°C than the grease composition of Comparative Example 4, and was found to be a grease composition that can reduce vibration and noise. Furthermore, the grease composition of Example 10 had a smoother appearance even at -20°C than the grease composition of Comparative Example 4, and furthermore, had lower starting torque at -20°C, indicating excellent low-temperature properties.

Claims

1. A grease composition comprising the following components (I) to (III): (I) base oil; (II) thickeners; (III) containing polymer block (A) and polymer block (B), The polymer block (A) contains, as a main structural unit, a structural unit (S) derived from an aromatic vinyl compound, The polymer block (B) contains a structural unit (T) derived from a conjugated diene compound as a main structural unit, and also contains a structural unit (X) represented by the following formula (X): Block copolymer or its hydrogenated product. 【Chemical 1】 (In formula (X), R １ ~R ３ are each independently a hydrogen atom or a hydrocarbon group having 1 to 11 carbon atoms. When the polymer block (B) contains two or more structural units (X), the plurality of R １ may be the same or different, and there are multiple R ２ may be the same or different, and there are multiple R ３ may be the same or different.)

2. The polymer block (B) contains, as the structural unit (X), R １ ~R ３ 2. The grease composition according to claim 1, comprising a structural unit (Xc) in which at least one of the structural units (Xc) is a hydrocarbon group having 1 to 11 carbon atoms.

3. 3. The grease composition according to claim 2, wherein the hydrocarbon group having 1 to 11 carbon atoms in the structural unit (Xc) is a methyl group.

4. The polymer block (B) contains, as the structural unit (X), R １ ~R ３ 2. The grease composition according to claim 1, comprising a structural unit (Xh) in which all of the following are hydrogen atoms.

5. 2. The grease composition according to claim 1, wherein the content of the structural unit (X) in the polymer block (B) is 0.5 mol % or more relative to 100 mol % of the total amount of structural units constituting the polymer block (B).

6. 3. The grease composition according to claim 2, wherein the content of the structural unit (Xc) in the polymer block (B) is 0.5 mol % or more relative to 100 mol % of the total amount of structural units constituting the polymer block (B).

7. 2. The grease composition according to claim 1, wherein the component (III) is a hydrogenated product of a block copolymer having an iodine value of 0 to 200 g / 100 g.

8. 2. The grease composition according to claim 1, wherein the amount of vinyl bonds in the polymer block (B) is 55 to 99 mol %.

9. 2. The grease composition according to claim 1, wherein component (III) has a temperature range over which tan δ is 1.0 or greater, as measured in accordance with JIS K7244-10:2005 under conditions of a strain of 0.1%, a frequency of 1 Hz, a measurement temperature of −70 to +100°C, and a heating rate of 3°C / min, and the maximum width of the temperature range is 12°C or greater.

10. 2. The grease composition according to claim 1, wherein the content of the structural unit (S) in the polymer block (A) is 70 mol % or more based on 100 mol % of the total amount of structural units constituting the polymer block (A).

11. 2. The grease composition according to claim 1, wherein the content of the structural unit (T) in the polymer block (B) is 30 mol % or more based on 100 mol % of the total amount of structural units constituting the polymer block (B).

12. 2. The grease composition according to claim 1, wherein the content of the polymer block (A) in the component (III) is 1 to 50 mass % relative to 100 mass % of the total amount of structural units constituting the component (III).

13. 2. The grease composition according to claim 1, wherein the total content of the polymer block (A) and the polymer block (B) in the component (III) is 90 to 100 mass % relative to 100 mass % of the total amount of structural units constituting the component (III).

14. 2. The grease composition according to claim 1, wherein the component (III) has at least one functional group selected from an alkoxysilyl group, a carboxy group, an amino group, a hydroxy group, an epoxy group, and a group derived from an acid anhydride.

15. The grease composition according to claim 14, wherein the content of the functional group in the component (III) is 0.1 to 5.0 phr.

16. 2. The grease composition according to claim 1, wherein the aromatic vinyl compound contains a styrene-based compound.

17. 17. The grease composition according to claim 16, wherein the content of structural units derived from a styrene-based compound in said component (III) is 1 to 25 mass% relative to 100 mass% of the total amount of structural units constituting said component (III).

18. 2. The grease composition according to claim 1, wherein the conjugated diene compound contains isoprene.

19. 2. The grease composition according to claim 1, wherein the content of the component (III) is 0.5 to 20 mass % relative to 100 mass % of the total amount of the grease composition.

20. The grease composition according to any one of claims 1 to 19, which is a noise-deadening grease composition.

21. A sliding member comprising the grease composition according to any one of claims 1 to 19.

22. 22. The sliding member according to claim 21, comprising at least one selected from metals and resins.

23. The slide member according to claim 21, which is an automobile part or an industrial machine part.

24. The sliding member according to claim 21, which is a part for a motor.

25. The method for producing a grease composition according to any one of claims 1 to 19, wherein a copolymer composition containing at least the component (I) and the component (III) and a thickener composition containing the component (I) and the component (II) are mixed together to prepare a grease composition containing the components (I) to (III).

26. Contains polymer block (A) and polymer block (B), The polymer block (A) contains, as a main structural unit, a structural unit (S) derived from an aromatic vinyl compound, The polymer block (B) contains a structural unit (T) derived from a conjugated diene compound as a main structural unit, and also contains a structural unit (X) represented by the following formula (X): A copolymer for a grease composition, which is a block copolymer or a hydrogenated product thereof. 【Chemistry 2】 (In formula (X), R １ ~R ３ are each independently a hydrogen atom or a hydrocarbon group having 1 to 11 carbon atoms. When the polymer block (B) contains two or more structural units (X), the plurality of R １ may be the same or different, and there are multiple R ２ may be the same or different, and there are multiple R ３ may be the same or different.)

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