Metal residue remover, metal residue remover system, production method for hydrogenated conjugated diene polymer, and hydrogenated conjugated diene polymer composition

Abstract

A metal residue remover that forms a complex with a metal residue when added to a polymer solution containing the metal residue, the topological polar surface area (TPSA) of the remover being 138 or less.

Description

Metal residue remover, metal residue remover system, method for producing hydrogenated conjugated diene polymer, and hydrogenated conjugated diene polymer composition

[0001] The present invention relates to a metal residue remover, a metal residue remover system, a method for producing a hydrogenated conjugated diene polymer, and a hydrogenated conjugated diene polymer composition.

[0002] BACKGROUND ART In recent years, thermoplastic elastomers have been widely used in a wide range of fields as soft materials having rubber elasticity, which do not require a vulcanization process and can be molded and recycled in the same manner as thermoplastic resins.

[0003] Examples of the thermoplastic elastomer include polymers of conjugated diene compounds such as 1,3-butadiene and isoprene, and copolymers of conjugated diene compounds with vinyl aromatic compounds such as styrene that are copolymerizable with the conjugated diene compounds. These are very useful as modifiers or adhesives for various materials such as impact-resistant transparent resins, polyolefins, polystyrene resins, and asphalt.

[0004] Furthermore, hydrogenated conjugated diene polymers in which hydrogen is added to the olefinic double bond moieties contained in the conjugated diene polymers have excellent weather resistance, and by taking advantage of this characteristic, the hydrogenated conjugated diene polymers are used in automobile parts, home appliance parts, electric wire coatings, medical parts, miscellaneous goods, footwear, protective films, pressure-sensitive adhesives, etc.

[0005] In general, conjugated diene polymers are produced by living anionic polymerization using alkyllithium or the like as a polymerization initiator. After the polymerization, the olefinic double bonds are subjected to a hydrogenation reaction (hereinafter also referred to as a "hydrogenation reaction" or "hydrogenation reaction") using a transition metal as a catalyst, thereby obtaining the hydrogenated conjugated diene polymer.

[0006] Various methods have been reported for hydrogenating conjugated diene polymers having olefinic double bonds. For example, a method is known in which a conjugated diene polymer is hydrogenated using a catalyst that combines a compound of a metal in Group VIII of the periodic table, particularly nickel or cobalt, with a predetermined reducing agent such as an alkylaluminum compound. Another known method is to hydrogenate the unsaturated double bonds of a conjugated diene polymer using a catalyst that combines a compound of titanium, which is a metal in Group IV of the periodic table, such as a bis(cyclopentadienyl)titanium compound, with a predetermined reducing agent such as an alkylaluminum compound or an alkyllithium compound.

[0007] As described above, thermoplastic elastomers, particularly the above-mentioned conjugated diene polymers and hydrogenated conjugated diene polymers, contain metal residues derived from the polymerization initiators, hydrogenation catalysts, etc. used in the production process. Metal residues in the polymer solution may cause lumps in the product, rough surfaces of molded articles, discoloration, reduced transparency, and filter clogging during processing, leading to various quality degradations, and therefore need to be efficiently removed in the production process.

[0008] As a specific method for producing a conjugated diene polymer, Patent Document 1 discloses a method for producing a conjugated diene polymer using an organolithium compound and a titanocene compound.

[0009] JP 2014-129479 A

[0010] As described above, since a metal catalyst is generally used in producing a conjugated diene polymer, the polymer solution contains metal residues, which may cause a problem of deterioration in the quality of the polymer product.

[0011] In view of the above-mentioned problems of the conventional art, the present invention aims to provide a metal residue remover that efficiently removes metal residues from a polymer solution containing these metal residues, a metal residue remover system containing the metal residue remover, a method for producing a hydrogenated conjugated diene polymer using the same, and a hydrogenated conjugated diene polymer composition.

[0012] The present inventors have conducted extensive research to solve the problems of the prior art described above, and as a result have found that a high metal removal effect can be achieved by using a metal residue remover having a specified TPSA (Topological Polar Surface Area) of not more than a predetermined value for a polymer solution containing metal residues, and have thus completed the present invention.

[0013] [1] A metal residue remover that forms a complex with metal residues when added to a polymer solution containing the metal residues, the metal residue remover having a TPSA (Topological Polar Surface Area) of 138 or less. [2] The metal residue remover according to [1] above, which is an organic compound having at least two polar functional groups. [3] The metal residue remover according to [2] above, wherein one of the at least two polar functional groups is selected from the group consisting of a hydroxy group (excluding a hydroxy group in a carboxyl group), a carbonyl group (excluding a carbonyl group in a carboxyl group), an ether group (excluding an ether group in an ester group), a primary amino group, a secondary amino group, a tertiary amino group, and an imino group. [4] A metal residue remover according to any one of [1] to [3] above, which has one each of the following functional group 1 and functional group 2, wherein the functional group 1 is any one selected from the group consisting of a hydroxy group (excluding the hydroxy group in a carboxyl group), a carbonyl group (excluding the carbonyl group in a carboxyl group), an ether group (excluding the ether group in an ester group), a primary amino group, a secondary amino group, a tertiary amino group, and an imino group, and the functional group 2 is any one selected from the group consisting of a hydroxy group (excluding the hydroxy group in a carboxyl group), a carbonyl group (excluding the carbonyl group in a carboxyl group), an ether group (excluding the ether group in an ester group), a secondary amino group, and an imino group.[5] A metal residue remover having one each of the following functional group 1 and functional group 2, wherein the functional group 1 is any one selected from the group consisting of a hydroxy group (excluding the hydroxy group in a carboxyl group), a carbonyl group (excluding the carbonyl group in a carboxyl group), an ether group (excluding the ether group in an ester group), a primary amino group, a secondary amino group, a tertiary amino group, and an imino group, and the functional group 2 is any one selected from the group consisting of a carbonyl group (excluding the carbonyl group in a carboxyl group), an ether group (excluding the ether group in an ester group), a secondary amino group, and an imino group, The metal residue removing agent according to any one of [1] to [3] above, wherein when the functional group 1 and the functional group 2 are all any one selected from the group consisting of hydroxy groups (excluding hydroxy groups in carboxyl groups) and ether groups (excluding ether groups in ester groups), there are three or more atoms other than O atoms between any O atom contained in the functional group 1 and the functional group 2 and any other O atom. [6] The metal residue removing agent according to any one of [1] to [3] above, which has three or more of the following functional groups 1, wherein the functional group 1 is at least one functional group selected from the group consisting of a hydroxy group (excluding hydroxy groups in carboxyl groups), a carbonyl group (excluding carbonyl groups in carboxyl groups), an ether group (excluding ether groups in ester groups), a primary amino group, a secondary amino group, a tertiary amino group, and an imino group.[7] A metal residue remover according to any one of [1] to [3] above, which has three functional groups 1: the functional group 1 is at least one functional group selected from the group consisting of a hydroxy group (excluding the hydroxy group in a carboxyl group), a carbonyl group (excluding the carbonyl group in a carboxyl group), an ether group (excluding the ether group in an ester group), a primary amino group, a secondary amino group, a tertiary amino group, and an imino group; and when all of the three functional groups 1 are selected from the group consisting of a hydroxy group (excluding the hydroxy group in a carboxyl group) and an ether group (excluding the ether group in an ester group), three or more atoms other than O atoms are present between any O atom contained in the functional group 1 and any other O atom. [8] A metal residue remover according to any one of [1] to [3] above, having four or more of the following functional groups 1, wherein the functional groups 1 are at least one functional group selected from the group consisting of a hydroxy group (excluding a hydroxy group in a carboxyl group), a carbonyl group (excluding a carbonyl group in a carboxyl group), an ether group (excluding an ether group in an ester group), a primary amino group, a secondary amino group, a tertiary amino group, and an imino group. [9] The metal residue remover according to any one of [1] to [8] above, wherein the metal residue is at least one selected from the group consisting of an alkali metal, an alkaline earth metal, a transition metal, and an earth metal.

[10] The metal residue remover according to any one of [1] to [9] above, wherein the metal residue is at least one selected from the group consisting of lithium, nickel, cobalt, titanium, and aluminum.

[11] The metal residue remover according to any one of [1] to

[10] above, wherein the metal residue is at least one selected from the group consisting of nickel, cobalt, and titanium.

[12] The metal residue remover according to any one of [1] to

[11] above, wherein the metal residue is at least one selected from the group consisting of lithium and titanium.

[13] The metal residue remover according to any one of [1] to

[12] above, wherein the metal residue is titanium.

[14] The metal residue removing agent according to any one of [1] to

[13] above, wherein the polymer solution is a conjugated diene polymer solution.

[15] The metal residue removing agent according to any one of [1] to

[14] above, wherein the polymer solution is a hydrogenated conjugated diene polymer solution.

[16] The metal residue removing agent according to any one of [1] to

[15] above, wherein the solvent of the polymer solution is any one selected from the group consisting of cyclohexane, normal hexane, methylcyclohexane, and mixtures thereof.

[17] The metal residue removing agent according to any one of [1] to

[16] above, wherein the metal residue is titanium derived from a hydrogenation catalyst, and wherein the metal residue is formed into a complex with titanium that accounts for 36 mass % or more of the total titanium in the polymer solution by adding the metal residue removing agent in an amount of 10 in a molar ratio relative to the titanium constituting the hydrogenation catalyst in the polymer solution.

[18] The metal residue removing agent according to any one of [1] to

[17] above, which has a structure represented by the following formula (I):

[0014]

[0015] In formula (I), R １ is C(R ３ ) ２ OH, C(R ３ )=O, hydrogen, an alkyl group containing 1 to 3 carbon atoms, and an alkoxy group containing 1 to 3 carbon atoms; ２ is C(R ３ ) ２ OH, and C(R ３ )=O, and R ３ are each independently selected from the group consisting of hydrogen and alkyl groups containing 1 to 3 carbon atoms.

[0016]

[19] The metal residue removing agent according to any one of [1] to

[17] above, which has a structure represented by the following formula (II):

[0017]

[0018] In formula (II), R ４is selected from the group consisting of hydrogen and alkyl groups containing 1 to 3 carbon atoms.

[0019]

[20] The metal residue removing agent according to any one of [1] to

[17] above, which has a structure represented by the following formula (III):

[0020]

[0021] In formula (III), R ５ are each independently an alkylene group containing 1 to 4 carbon atoms.

[0022]

[21] The metal residue removing agent according to any one of [1] to

[20] , wherein the molecular weight of the metal residue removing agent is 250 or less.

[22] A metal residue removing agent system comprising the metal residue removing agent according to any one of [1] to

[21] , and a surfactant.

[23] The metal residue removing agent system according to

[22] , wherein the surfactant is an aliphatic carboxylic acid having 8 to 18 carbon atoms.

[24] A method for producing a hydrogenated conjugated diene polymer, comprising: Step 1 of obtaining a conjugated diene polymer in the presence of a polymerization initiator and hydrogenating the conjugated diene polymer in the presence of a hydrogenation catalyst to obtain a hydrogenated conjugated diene polymer solution; Step 2 of mixing the hydrogenated conjugated diene polymer solution with the metal residue removing agent according to any one of claims 1 to 21 to obtain a complex; and Step 3 of separating the complex to separate and recover the hydrogenated conjugated diene polymer.

[25] The method for producing a hydrogenated conjugated diene polymer according to

[24] above, wherein a surfactant is mixed in an amount of 0.5 parts by mass or less relative to 100 parts by mass of the hydrogenated conjugated diene polymer in step 2.

[26] The method for producing a hydrogenated conjugated diene polymer according to

[25] above, wherein the surfactant is an aliphatic carboxylic acid having 8 to 18 carbon atoms.

[27] The method for producing a hydrogenated conjugated diene polymer according to

[25] or

[26] above, wherein the method for separating the complex in step 3 is extraction into an aqueous layer.

[28] The method for producing a hydrogenated conjugated diene polymer according to any one of

[24] to

[27] above, wherein the metal residue removing agent is added in an amount of 0.001 to 10 parts by mass relative to 100 parts by mass of the hydrogenated conjugated diene polymer solution in step 2.

[29] A hydrogenated conjugated diene polymer composition comprising a hydrogenated conjugated diene polymer, metal residue, and the metal residue remover according to claim 1, wherein the content of the metal residue remover is 0.1 to 1000 ppm.

[0023] According to the present invention, it is possible to provide a metal residue remover capable of efficiently removing metal residues remaining in a polymer solution, and a hydrogenated conjugated diene-based polymer with reduced metal residues.

[0024] Hereinafter, a mode for carrying out the present invention (hereinafter referred to as "the present embodiment") will be described in detail. The present invention is not limited to the following embodiment, and various modifications can be made within the scope of the gist thereof.

[0025] [Metal Residue Remover] The metal residue remover of this embodiment is a metal residue remover that forms a complex with the metal residue when added to a polymer solution containing the metal residue, and has a TPSA (Topological Polar Surface Area) of 138 or less. By having the above configuration, the metal residue remover of this embodiment can efficiently remove metal residue remaining in the polymer solution. The metal residue remover of this embodiment has appropriate polarity, which allows it to strongly interact with metal atoms to form a complex, thereby exerting the effect of removing metal residue.

[0026] The metal residue remover of this embodiment is preferably an organic compound having a polar functional group from the viewpoint of interaction with metal atoms. Among polar functional groups, hydroxy groups (excluding hydroxy groups in carboxyl groups), carbonyl groups (excluding carbonyl groups in carboxyl groups), ether groups (excluding ether groups in ester groups), primary amino groups, secondary amino groups, tertiary amino groups, and imino groups tend to interact strongly with metal atoms. In particular, hydroxy groups (excluding hydroxy groups in carboxyl groups), carbonyl groups (excluding carbonyl groups in carboxyl groups), ether groups (excluding ether groups in ester groups), amino groups, and imino groups tend to interact strongly with metal atoms in this order, and among amino groups, tertiary amino groups, secondary amino groups, and primary amino groups tend to interact strongly with metal atoms in this order. Generally, the more polar functional groups there are, the higher the polarity tends to be. Among the polar functional groups, the polarity tends to be higher when they have a hydroxy group (excluding the hydroxy group in a carboxyl group), a carbonyl group (excluding the carbonyl group in a carboxyl group), an ether group (excluding the ether group in an ester group), a primary amino group, a secondary amino group, a tertiary amino group, or an imino group. Among these polar functional groups, the polarity tends to be higher in the order of hydroxy group (excluding the hydroxy group in a carboxyl group), amino group, carbonyl group (excluding the carbonyl group in a carboxyl group), imino group, and ether group (excluding the ether group in an ester group). Among amino groups, the polarity tends to be higher in the order of primary amino group, secondary amino group, and tertiary amino group. Generally, the more polar functional groups there are, the stronger the interaction with metal atoms. Furthermore, when the heteroatoms in the polar functional group are arranged at an appropriate distance, they tend to interact strongly with metal atoms. Specifically, the distance is preferably 1 to 5 atoms, more preferably 2 to 5 atoms, and even more preferably 3 to 4 atoms.

[0027] (TPSA) The metal residue removing agent of this embodiment has a TPSA (Topological Polar Surface Area) of 138 or less. TPSA is the polar surface area, and is the area value of the polar portion of the molecular surface. Generally, from the viewpoint of being compatible with a polymer solution in which a low-polarity solvent such as normal hexane or cyclohexane is used and promoting a reaction with metal residues in the polymer solution, the metal residue removing agent of this embodiment has a TPSA of 138 or less, preferably 115 or less, more preferably 90 or less, even more preferably 80 or less, and still more preferably 70 or less. On the other hand, from the viewpoint of strongly interacting with metal atoms in metal residues, the metal residue removing agent of this embodiment has a TPSA of preferably 1 or more, more preferably 21 or more, even more preferably 24 or more, even more preferably 33 or more, and still more preferably 41 or more. TPSA can be controlled to fall within the above-mentioned range by adjusting the type and number of polar functional groups that constitute the metal residue remover of this embodiment.

[0028] (Polar Functional Group) From the viewpoint of strong interaction with metal atoms in the metal residue, the metal residue remover of this embodiment is preferably an organic compound having at least two polar functional groups. The polar functional groups are not limited to those generally recognized in the field of metal residue removers used in polymer solutions, and examples thereof include a hydroxy group, a carbonyl group, an ether group, a primary amino group, a secondary amino group, a tertiary amino group, an imino group, a carboxyl group, a cyano group, a boryl group, a mercapto group, a thiocarbonyl group, a thioether group, a sulfoxide group, a sulfone group, a phosphino group, and a phosphine oxide group.

[0029] From the viewpoint of strongly interacting with the metal atoms in the metal residue, it is preferable that at least one of the polar functional groups in the metal residue remover of this embodiment is selected from the group consisting of a hydroxy group (excluding the hydroxy group in a carboxyl group), a carbonyl group (excluding the carbonyl group in a carboxyl group), an ether group (excluding the ether group in an ester group), a primary amino group, a secondary amino group, a tertiary amino group, and an imino group. From the viewpoint of strongly interacting with the metal atoms, the polar functional groups are preferably hydroxy groups (excluding the hydroxy group in a carboxyl group), a carbonyl group (excluding the carbonyl group in a carboxyl group), an ether group (excluding the ether group in an ester group), an amino group, and an imino group, in that order. Among amino groups, tertiary amino groups are more preferable, followed by secondary amino groups and primary amino groups. From the viewpoint of increasing polarity, the polar functional group is preferably a hydroxy group (excluding the hydroxy group in a carboxyl group), an amino group, a carbonyl group (excluding the carbonyl group in a carboxyl group), an imino group, or an ether group (excluding the ether group in an ester group), in that order. Among amino groups, a primary amino group, a secondary amino group, and a tertiary amino group are preferred, in that order.

[0030] From the viewpoint of achieving an excellent balance between the strength of interaction with metal atoms in metal residues and polarity, the metal residue remover of the present embodiment preferably has one functional group 1 and one functional group 2, wherein the functional group 1 is any one selected from the group consisting of a hydroxy group (excluding hydroxy groups in carboxyl groups), a carbonyl group (excluding carbonyl groups in carboxyl groups), an ether group (excluding ether groups in ester groups), a primary amino group, a secondary amino group, a tertiary amino group, and an imino group, and the functional group 2 is any one selected from the group consisting of a hydroxy group (excluding hydroxy groups in carboxyl groups), a carbonyl group (excluding carbonyl groups in carboxyl groups), an ether group (excluding ether groups in ester groups), a secondary amino group, and an imino group. From the viewpoint of strong interaction with metal atoms, the functional group 1 is preferably a hydroxy group (excluding the hydroxy group in a carboxyl group), a carbonyl group (excluding the carbonyl group in a carboxyl group), an ether group (excluding the ether group in an ester group), an amino group, or an imino group, in that order. Among amino groups, the preferred are a tertiary amino group, a secondary amino group, or a primary amino group, in that order. Furthermore, from the viewpoint of increasing polarity, the functional group 1 is preferably a hydroxy group (excluding the hydroxy group in a carboxyl group), an amino group, a carbonyl group (excluding the carbonyl group in a carboxyl group), an imino group, or an ether group (excluding the ether group in an ester group), in that order. Among amino groups, the preferred are a primary amino group, a secondary amino group, or a tertiary amino group, in that order. From the viewpoint of strong interaction with metal atoms, the functional group 2 is preferably a hydroxy group (excluding the hydroxy group in a carboxyl group), a carbonyl group (excluding the carbonyl group in a carboxyl group), an ether group (excluding the ether group in an ester group), a secondary amino group, and an imino group, in that order. Also, from the viewpoint of increasing polarity, the functional group 2 is preferably a hydroxy group (excluding the hydroxy group in a carboxyl group), a secondary amino group, a carbonyl group (excluding the carbonyl group in a carboxyl group), an imino group, and an ether group (excluding the ether group in an ester group), in that order.

[0031] Furthermore, from the viewpoint of achieving an excellent balance between the strength of interaction with metal atoms in metal residues and polarity, the metal residue remover of this embodiment has one each of functional group 1 and functional group 2, wherein functional group 1 is any one selected from the group consisting of a hydroxy group (excluding hydroxy groups in carboxyl groups), a carbonyl group (excluding carbonyl groups in carboxyl groups), an ether group (excluding ether groups in ester groups), a primary amino group, a secondary amino group, a tertiary amino group, and an imino group, and functional group 2 is any one selected from the group consisting of a carbonyl group (excluding carbonyl groups in carboxyl groups), an ether group (excluding ether groups in ester groups), a primary amino group, a secondary amino group, a tertiary amino group, and an imino group. Preferably, the functional group 1 is any one selected from the group consisting of an ether group (excluding ether groups in ester groups), a secondary amino group, and an imino group. Furthermore, from the viewpoint of reactivity with metal atoms in metal residues, when the functional group 1 and the functional group 2 are all any one selected from the group consisting of a hydroxy group (excluding hydroxy groups in carboxyl groups) and an ether group (excluding ether groups in ester groups), it is preferable that there are three or more atoms other than O atoms between any O atom contained in the functional group 1 and the functional group 2 and any other O atom. From the viewpoint of strong interaction with metal atoms, the functional group 1 is preferably a hydroxy group (excluding hydroxy groups in carboxyl groups), a carbonyl group (excluding carbonyl groups in carboxyl groups), an ether group (excluding ether groups in ester groups), an amino group, and an imino group, in that order. Among amino groups, the preferred are a tertiary amino group, a secondary amino group, and a primary amino group, in that order. From the viewpoint of increasing polarity, the functional group 1 is preferably a hydroxy group (excluding the hydroxy group in a carboxyl group), an amino group, a carbonyl group (excluding the carbonyl group in a carboxyl group), an imino group, and an ether group (excluding the ether group in an ester group), in that order. Among amino groups, the preferred are a primary amino group, a secondary amino group, and a tertiary amino group, in that order. From the viewpoint of strong interaction with metal atoms, the functional group 2 is preferably a carbonyl group (excluding the carbonyl group in a carboxyl group), an ether group (excluding the ether group in an ester group), a secondary amino group, and an imino group, in that order.From the viewpoint of increasing polarity, the functional group 2 is preferably, in this order, a secondary amino group, a carbonyl group (excluding the carbonyl group in a carboxyl group), an imino group, and an ether group (excluding the ether group in an ester group).

[0032] Furthermore, from the viewpoint of achieving an excellent balance between the strength of interaction with metal atoms in metal residues and polarity, the metal residue remover of this embodiment is a metal residue remover having three or more functional groups 1, and the functional groups 1 are preferably at least one functional group selected from the group consisting of a hydroxy group (excluding the hydroxy group in a carboxyl group), a carbonyl group (excluding the carbonyl group in a carboxyl group), an ether group (excluding the ether group in an ester group), a primary amino group, a secondary amino group, a tertiary amino group, and an imino group. From the viewpoint of a strong interaction with metal atoms, the polar functional groups are preferably hydroxy groups (excluding the hydroxy group in a carboxyl group), a carbonyl group (excluding the carbonyl group in a carboxyl group), an ether group (excluding the ether group in an ester group), an amino group, and an imino group, in that order. Among amino groups, tertiary amino groups are more preferred, followed by secondary amino groups and primary amino groups. From the viewpoint of increasing polarity, the polar functional groups are preferably, in this order, hydroxyl groups (excluding hydroxyl groups in carboxyl groups), amino groups, carbonyl groups (excluding carbonyl groups in carboxyl groups), imino groups, and ether groups (excluding ether groups in ester groups). Among amino groups, primary amino groups, secondary amino groups, and tertiary amino groups are preferred. The three or more functional groups 1 may be one type alone or two or more types.

[0033] Furthermore, from the viewpoint of achieving an excellent balance between the strength of interaction with metal atoms in metal residues and polarity, the metal residue remover of this embodiment is a metal residue remover having three functional groups 1, and the functional groups 1 are preferably at least one functional group selected from the group consisting of a hydroxy group (excluding the hydroxy group in a carboxyl group), a carbonyl group (excluding the carbonyl group in a carboxyl group), an ether group (excluding the ether group in an ester group), a primary amino group, a secondary amino group, a tertiary amino group, and an imino group. From the viewpoint of a strong interaction with metal atoms, the polar functional groups are preferably hydroxy groups (excluding the hydroxy group in a carboxyl group), a carbonyl group (excluding the carbonyl group in a carboxyl group), an ether group (excluding the ether group in an ester group), an amino group, and an imino group, in that order. Among amino groups, tertiary amino groups are more preferred, followed by secondary amino groups and primary amino groups. From the viewpoint of increasing polarity, the polar functional group is preferably a hydroxy group (excluding the hydroxy group in a carboxyl group), an amino group, a carbonyl group (excluding the carbonyl group in a carboxyl group), an imino group, or an ether group (excluding the ether group in an ester group), in that order. Among amino groups, a primary amino group, a secondary amino group, and a tertiary amino group are preferred, in that order. The metal residue removing agent of the present embodiment is a metal residue removing agent having three functional groups 1, wherein the functional group 1 is at least one functional group selected from the group consisting of a hydroxy group (excluding the hydroxy group in a carboxyl group), a carbonyl group (excluding the carbonyl group in a carboxyl group), an ether group (excluding the ether group in an ester group), a primary amino group, a secondary amino group, a tertiary amino group, and an imino group, and when all of the three functional groups 1 are selected from the group consisting of a hydroxy group (excluding the hydroxy group in a carboxyl group) and an ether group (excluding the ether group in an ester group), it is preferable that there be three or more atoms other than O atoms between any O atom contained in the functional group 1 and any other O atom. In other words, it is preferable that there be three or more atoms other than O atoms between all pairs obtained by arbitrarily selecting two O atoms from the functional group 1.Specifically, diethylene glycol and glycerol do not have three or more atoms other than O atoms between any two O atoms, and trimethylolmethane has three or more atoms other than O atoms between any two O atoms. The three functional groups 1 may be of one type alone or of two or more types.

[0034] Furthermore, from the viewpoint of achieving an excellent balance between the strength of interaction with metal atoms in metal residues and polarity, the metal residue remover of this embodiment is a metal residue remover having four or more functional groups 1, and the functional groups 1 are preferably at least one functional group selected from the group consisting of a hydroxy group (excluding the hydroxy group in a carboxyl group), a carbonyl group (excluding the carbonyl group in a carboxyl group), an ether group (excluding the ether group in an ester group), a primary amino group, a secondary amino group, a tertiary amino group, and an imino group. From the viewpoint of a strong interaction with metal atoms, the polar functional groups are preferably hydroxy groups (excluding the hydroxy group in a carboxyl group), a carbonyl group (excluding the carbonyl group in a carboxyl group), an ether group (excluding the ether group in an ester group), an amino group, and an imino group, in that order. Among amino groups, tertiary amino groups are more preferred, followed by secondary amino groups and primary amino groups. From the viewpoint of increasing polarity, the polar functional groups are preferably, in this order, hydroxyl groups (excluding hydroxyl groups in carboxyl groups), amino groups, carbonyl groups (excluding carbonyl groups in carboxyl groups), imino groups, and ether groups (excluding ether groups in ester groups). Among amino groups, primary amino groups, secondary amino groups, and tertiary amino groups are preferred. The four or more functional groups 1 may be one type alone or two or more types.

[0035] (Characteristics of Metal Residue Removing Agent) As described above, the metal residue removing agent of this embodiment is added to a polymer solution containing metal residues to form a complex with the metal residues. From the viewpoint of efficiently removing metal residues from a polymer solution, for example, when the polymer solution contains titanium constituting a hydrogenation catalyst, adding the metal residue removing agent of this embodiment in a molar ratio (metal residue removing agent / titanium) of 10 relative to the titanium constituting the hydrogenation catalyst preferably forms a complex with 36% by mass or more of the total titanium in the polymer solution. More preferably, it forms a complex with 50% by mass or more of titanium, even more preferably it forms a complex with 60% by mass or more of titanium, and even more preferably it forms a complex with 70% by mass or more of titanium. By adjusting the type, number, and positional relationship of the polar functional groups constituting the metal residue removing agent and adjusting the TPSA to 138 or less, the ability to form a complex with titanium can be improved and the above-mentioned numerical range can be achieved.

[0036] (Suitable Structure of Metal Residue Remover) From the viewpoint of efficiently removing metal residues in a polymer solution, the metal residue remover of the present embodiment is preferably an organic compound having a structure represented by the following formula (I), formula (II), or formula (III):

[0037]

[0038] In formula (I), R １ is C(R ３ ) ２ OH, C(R ３ )=O, hydrogen, an alkyl group containing 1 to 3 carbon atoms, and an alkoxy group containing 1 to 3 carbon atoms. Among these, from the viewpoint of excellent balance between the strength of interaction with the metal atoms in the metal residue and polarity, R １ is C(R ３ ) ２ OH, C(R ３ )=O, hydrogen, an alkyl group containing 1 to 2 carbon atoms, or an alkoxy group containing 1 to 2 carbon atoms is preferred, and C(R ３ ) ２ OH, C(R ３)=O, hydrogen, an alkyl group containing one carbon atom, or an alkoxy group containing one carbon atom is more preferred, and C(R ３ ) ２ OH is more preferred. ２ is C(R ３ ) ２ OH, and C(R ３ Among these, from the viewpoint of excellent balance between the strength of interaction with the metal atoms in the metal residue and polarity, R ２ is preferably either hydrogen or an alkyl group containing 1 to 3 carbon atoms, more preferably either hydrogen or an alkyl group containing 1 to 2 carbon atoms, and even more preferably either hydrogen or an alkyl group containing 1 carbon atom. ３ are each independently any one selected from the group consisting of hydrogen and alkyl groups containing 1 to 3 carbon atoms. Among these, R ３ is preferably either hydrogen or an alkyl group containing 1 to 3 carbon atoms, more preferably either hydrogen or an alkyl group containing 1 to 2 carbon atoms, and even more preferably either hydrogen or an alkyl group containing 1 carbon atom. A metal residue remover having a structure in which these polar functional groups are in such a number and positional relationship tends to be able to strongly interact with metal atoms in metal residues, and by forming a highly polar metal complex, tends to be able to efficiently remove metal residues.

[0039]

[0040] In formula (II), R ４ is selected from the group consisting of hydrogen and alkyl groups containing 1 to 3 carbon atoms. Among these, R ４ is preferably either hydrogen or an alkyl group containing 1 to 2 carbon atoms, and from the viewpoint of ease of handling, R ４is preferably an alkyl group containing 1 to 3 carbon atoms, more preferably an alkyl group containing 1 to 2 carbon atoms, and even more preferably an alkyl group containing 2 carbon atoms. Metal residue removers having a structure in which these polar functional groups are present in such a number and positional relationship tend to be able to strongly interact with metal atoms in metal residues, and by forming a highly polar metal complex, tend to be able to more efficiently remove metal residues.

[0041]

[0042] In formula (III), R ５ are each independently an alkylene group containing 1 to 4 carbon atoms. Among these, R ５ is preferably an alkylene group containing 1 to 3 carbon atoms, more preferably an alkylene group containing 2 to 3 carbon atoms, even more preferably an alkylene group containing 2 carbon atoms, and even more preferably an ethylene group. Metal residue removers having such polar functional groups in a structure with such a number and positional relationship tend to be able to strongly interact with metal atoms in metal residues, and by forming a highly polar metal complex, tend to be able to efficiently remove metal residues.

[0043] (Molecular Weight of Metal Residue Removing Agent) From the viewpoints of ease of handling and economic efficiency, the molecular weight of the metal residue removing agent of the present embodiment is preferably 250 or less, more preferably 200 or less, even more preferably 170 or less, and even more preferably 150 or less.

[0044] [Polymer Solution] As described above, the metal residue removing agent of this embodiment is added to a polymer solution containing metal residue to form a complex with the metal residue. The polymer solution to which the metal residue removing agent of this embodiment is added is not particularly limited as long as it is one that is commonly used in the field in which the metal residue removing agent is applied, and examples thereof include solutions containing the following polymers and solvents.

[0045] (Polymer) The polymer constituting the polymer solution to which the metal residue removing agent of this embodiment is added is not particularly limited as long as it is one commonly used in the field in which the metal residue removing agent is applied. For example, polymers obtained by polymerizing various compounds in the presence of a polymerization initiator, polymers obtained by hydrogenating various monomer units in the presence of a hydrogenation catalyst, and polymers obtained by chemical modification such as modification can be used. Specific examples include conjugated diene polymers, hydrogenated conjugated diene polymers, olefin polymers, cyclic olefin polymers, and hydrogenated cyclic olefin polymers. Among these, conjugated diene polymers are preferred because the polymer solution is generally easy to handle, and hydrogenated conjugated diene polymers are more preferred.

[0046] <Conjugated Diene Polymer> The conjugated diene polymer is preferably a polymer containing a vinyl aromatic monomer unit and a conjugated diene monomer unit.

[0047] [Conjugated Diene Compound] The conjugated diene monomer units constituting the conjugated diene polymer are formed by polymerizing a conjugated diene compound. Examples of the conjugated diene compound include, but are not limited to, 1,3-butadiene, isoprene, piperylene, 2,3-dimethyl-1,3-butadiene, 2-methyl-1,3-pentadiene, 1,3-hexadiene, 3,4-dimethyl-1,3-hexadiene, 4,5-diethyl-1,3-octadiene, phenylbutadiene, α-farnesene, β-farnesene, and 1,3,7-octatriene, and other conjugated diene compounds containing 4 to 15 carbon atoms. Among these, 1,3-butadiene and isoprene are preferred from the viewpoint of economy.

[0048] [Vinyl Aromatic Compound] The vinyl aromatic monomer units constituting the conjugated diene polymer are formed by polymerizing a vinyl aromatic compound. Examples of vinyl aromatic compounds include, but are not limited to, styrene, styrenes substituted with alkyl groups such as α-methylstyrene, p-methylstyrene, and p-tert-butylstyrene, divinylbenzene, 1,1-diphenylethylene, N,N-dimethyl-p-aminoethylstyrene, N,N-diethyl-p-aminoethylstyrene, 2-vinylpyridine, 4-vinylpyridine, vinylnaphthalene, and vinyl allyl compounds such as vinylnaphthalenes substituted with alkyl groups. Among these, styrene is preferred from the viewpoint of economy.

[0049] [Polymerization Initiator] The polymerization initiator used in the production of the polymer is not particularly limited, and examples thereof include organic alkali metal compounds such as aliphatic hydrocarbon alkali metal compounds, aromatic hydrocarbon alkali metal compounds, and organic amino alkali metal compounds, which are generally known to have anionic polymerization activity for vinyl aromatic compounds and conjugated dienes. Examples of organic alkali metal compounds include, but are not limited to, aliphatic and aromatic hydrocarbon lithium compounds having 1 to 20 carbon atoms, such as compounds containing one lithium atom per molecule, dilithium compounds containing multiple lithium atoms per molecule, trilithium compounds, tetralithium compounds, and multilithium compounds. Specific examples include n-propyllithium, n-butyllithium, sec-butyllithium, tert-butyllithium, n-pentyllithium, n-hexyllithium, benzyllithium, phenyllithium, tolyllithium, a reaction product of diisopropenylbenzene and sec-butyllithium, and a reaction product of divinylbenzene, sec-butyllithium, and a small amount of 1,3-butadiene. The amount of such a polymerization initiator used can be any amount commonly used in the field of polymer production, and can be adjusted appropriately depending on the molecular weight of the target polymer.

[0050] <Hydrogenated Conjugated Diene Polymer> The hydrogenated conjugated diene polymer is preferably a polymer obtained by subjecting the conjugated diene polymer to a hydrogenation reaction using a hydrogenation catalyst.

[0051] [Hydrogenation Catalyst] The hydrogenation catalyst is not particularly limited and examples thereof include known catalysts such as (1) supported heterogeneous hydrogenation catalysts in which a metal such as Ni, Pt, Pd, or Ru is supported on carbon, silica, alumina, or diatomaceous earth, (2) so-called Ziegler-type hydrogenation catalysts that use a transition metal salt such as an organic acid salt or an acetylacetone salt of Ni, Co, Fe, Cr, or the like, and a reducing agent such as an organoaluminum, and (3) homogeneous hydrogenation catalysts such as so-called organometallic complexes of organometallic compounds such as Ti, Ru, Rh, or Zr. Specific examples include the hydrogenation catalysts described in JP-B Nos. 42-8704, 43-6636, 63-4841, 1-37970, 1-53851, and 2-9041. Suitable hydrogenation catalysts include titanocene compounds, nickel-based Ziegler-type hydrogenation catalysts, cobalt-based Ziegler-type hydrogenation catalysts, and mixtures thereof.

[0052] Examples of the titanocene compound include, but are not limited to, compounds described in JP-A-8-109219. Specific examples include compounds having at least one ligand having a (substituted) cyclopentadienyl skeleton, an indenyl skeleton, or a fluorenyl skeleton, such as biscyclopentadienyltitanium dichloride and monopentamethylcyclopentadienyltitanium trichloride, as well as compounds obtained by reducing these titanocene compounds with a reducing organic compound. Examples of the reducing organic compound include, but are not limited to, organic alkali metal compounds such as organolithium compounds, organomagnesium compounds, organoaluminum compounds, organoboron compounds, and organozinc compounds.

[0053] The nickel-based Ziegler hydrogenation catalyst includes a catalyst containing a nickel compound and an organoaluminum. Examples of the nickel compound include, but are not limited to, nickel acetate, nickel propionate, nickel butanoate, nickel valerate, nickel hexanoate, nickel octanoate, nickel 2-ethylhexanoate, nickel decanoate, nickel neodecanoate, nickel benzoate, nickel naphthoate, nickel acetylacetonate, and nickel dibenzoylmethanate. Examples of the organoaluminum include, but are not limited to, trimethylaluminum, triethylaluminum, and triisobutylaluminum.

[0054] The cobalt-based Ziegler hydrogenation catalyst includes a catalyst containing a cobalt compound and an organoaluminum. Examples of the cobalt compound include, but are not limited to, cobalt acetate, cobalt propionate, cobalt butanoate, cobalt valerate, cobalt hexanoate, cobalt octanoate, cobalt 2-ethylhexanoate, cobalt decanoate, cobalt neodecanoate, cobalt benzoate, cobalt naphthoate, cobalt acetylacetonate, and cobalt dibenzoylmethanate. Examples of the organoaluminum include, but are not limited to, trimethylaluminum, triethylaluminum, and triisobutylaluminum.

[0055] (Metal Residue) The metal residue contained in the polymer solution to which the metal residue removing agent of this embodiment is added is preferably at least one selected from the group consisting of alkali metals, alkaline earth metals, transition metals, and earth metals. In the production of polymers, compounds commonly used as polymerization initiators, hydrogenation catalysts, and reducing agents for hydrogenation catalysts contain lithium, nickel, cobalt, titanium, aluminum, and the like, and therefore the metal residue is preferably one of these metals. In particular, compounds commonly used as hydrogenation catalysts contain nickel, cobalt, and titanium, and therefore the metal residue is more preferably one of these metals. Compounds used as particularly highly active hydrogenation catalysts contain titanium, and therefore the metal residue is even more preferably titanium. Furthermore, from the viewpoint of producing a polymer solution with a small amount of metal residue, the metal residue contained in the polymer solution to which the metal residue removing agent of this embodiment is added is even more preferably lithium or titanium.

[0056] (Solvent) The solvent of the polymer solution to which the metal residue removing agent of this embodiment is added is not particularly limited as long as it is one commonly used in the field of polymer production, but examples thereof include aliphatic hydrocarbons such as n-butane, isobutane, n-pentane, n-hexane, n-heptane, and n-octane; alicyclic hydrocarbons such as cyclohexane, cycloheptane, and methylcycloheptane; and aromatic hydrocarbons such as benzene, toluene, xylene, and ethylbenzene. From the viewpoints of polymer solubility and economic efficiency, cyclohexane, normal hexane, methylcyclohexane, or a mixture thereof is preferred. Furthermore, in order to extract metal residues into the aqueous layer, the solvent must have low polarity and be immiscible with water. From the viewpoint of separability from water, the solvent of the polymer solution is preferably cyclohexane, normal hexane, methylcyclohexane, or a mixture thereof. From the viewpoint of economic efficiency, cyclohexane, normal hexane, or a mixture thereof is more preferred.

[0057] [Metal Residue Removing Agent System] The metal residue removing agent system of this embodiment contains the metal residue removing agent of this embodiment described above and a surfactant. By using the metal residue removing agent system of this embodiment, metal residues in a polymer solution can be efficiently removed.

[0058] (Surfactant) The surfactant used in the metal residue remover system of the present embodiment is not particularly limited as long as it is a surfactant that is commonly used, and examples thereof include anionic surfactants, cationic surfactants, nonionic surfactants, and amphoteric surfactants. These may be used singly or in combination of two or more.

[0059] Examples of anionic surfactants include, but are not limited to, carboxylic acid types such as aliphatic carboxylates and polyoxyethylene alkyl ether carboxylates; sulfonic acid types such as alkanesulfonates and alkylbenzenesulfonates; sulfates such as alkyl sulfates and polyoxyethylene alkyl ether sulfates; and phosphates such as alkyl phosphates and polyoxyethylene alkyl ether phosphates. These may also be used in the form of free acids.

[0060] Furthermore, polymeric anionic surfactants can be used as the anionic surfactant. Examples of polymeric anionic surfactants include, but are not limited to, polycarboxylic acids and their salts; sulfonic acid group-containing polymers and their salts; and other anionic polymers such as carboxymethyl cellulose, sodium alginate, and rosin soap. Examples of polycarboxylic acids and their salts include, but are not limited to, (meth)acrylic acid polymers and their salts; polymers of unsaturated dibasic acids such as maleic anhydride, maleic acid, fumaric acid, and itaconic acid, or copolymers with other monomers and their salts. Examples of sulfonic acid group-containing polymers include, but are not limited to, lignin sulfonic acid, formalin condensates of naphthalene (or alkylnaphthalene) sulfonic acid, formalin condensates of benzene (or alkylbenzene) sulfonic acid, formalin condensates of aromatic sulfonic acids such as formalin condensates of sulfonated creosote oil, and polymers of vinyl sulfonic acid.

[0061] Examples of cationic surfactants include, but are not limited to, alkylamine salt types such as monoalkylamine salts, dialkylamine salts, and trialkylamine salts; and quaternary ammonium salt types such as alkyltrimethylammonium halides, dialkyldimethylammonium halides, and alkylbenzalkonium chloride.

[0062] Nonionic surfactants include, but are not limited to, ester types such as glycerin fatty acid esters and sorbitan fatty acid esters; ether types such as polyoxyethylene alkyl ethers and polyoxyethylene alkylphenyl ethers; ester ether types such as fatty acid polyethylene glycols and fatty acid polyoxyethylene sorbitan; and alkanolamide types such as fatty acid alkanolamides.

[0063] Examples of amphoteric surfactants include, but are not limited to, carboxybetaine surfactants such as alkylbetaine and fatty acid amidopropyl betaine; 2-alkylimidazoline derivative surfactants such as 2-alkyl-N-carboxymethyl-N-hydroxyethylimidazolinium betaine; glycine surfactants such as alkyldiethylenetriaminoacetic acid; and amine oxide surfactants such as alkylamine oxide.

[0064] As the surfactant, an anionic surfactant is preferred from the viewpoint of metal residue removal efficiency. As the anionic surfactant, aliphatic carboxylic acids, polycarboxylates, and polyoxyethylene alkyl ether phosphates are preferred from the viewpoint of metal residue removal efficiency. Among these, aliphatic carboxylic acids having 8 to 18 carbon atoms are more preferred.

[0065] <Aliphatic Carboxylic Acid> From the viewpoints of economy and ease of handling, the aliphatic carboxylic acid is preferably an aliphatic carboxylic acid having 8 to 18 carbon atoms. Specific examples include, but are not limited to, octanoic acid, nonanoic acid, decanoic acid, lauric acid, myristic acid, palmitic acid, stearic acid, palmitoleic acid, oleic acid, and linoleic acid. These may be used alone or in combination of two or more.

[0066] <Polycarboxylate> From the viewpoints of economy and ease of handling, the polycarboxylate is preferably a sodium salt of an olefin-maleic acid copolymer or a sodium salt of a styrene-maleic acid copolymer. Specific examples include, but are not limited to, Polystar OM, OMR, A-1060, and SMX-1H manufactured by NOF Corporation, and XIRAN 2000HNa, 3000HNa, 3500HNa, and 3600HNa manufactured by Polyscope Polymers BV. These may be used alone or in combination of two or more.

[0067] <Polyoxyethylene alkyl ether calcium phosphate> From the viewpoints of economy and ease of handling, the polyoxyethylene alkyl ether phosphate is preferably a polyoxyethylene alkyl ether calcium phosphate. Specific examples include, but are not limited to, ADEKACOL PS-440E, PS-810E, and PS-807 manufactured by ADEKA CORPORATION, and Phosphanol RB-410, RD-510Y, RL-310, RS-610, and RS-710 manufactured by Toho Chemical Industry Co., Ltd. These may be used alone or in combination of two or more.

[0068] [Method for Producing Hydrogenated Conjugated Diene Polymer] The method for producing a hydrogenated conjugated diene polymer of this embodiment includes Step 1 of obtaining a conjugated diene polymer in the presence of a polymerization initiator and hydrogenating the conjugated diene polymer in the presence of a hydrogenation catalyst to obtain a hydrogenated conjugated diene polymer solution, Step 2 of mixing the hydrogenated conjugated diene polymer solution with the metal residue removing agent of this embodiment described above to obtain a complex, and Step 3 of separating the complex to separate and recover the hydrogenated conjugated diene polymer.

[0069] (Step 1) In the method for producing a hydrogenated conjugated diene polymer of this embodiment, step 1 is a step of obtaining a hydrogenated conjugated diene polymer solution, which comprises a polymerization reaction to obtain a conjugated diene polymer in the presence of a polymerization initiator and a hydrogenation reaction of the conjugated diene polymer in the presence of a hydrogenation catalyst.

[0070] <Polymerization Reaction> Conventional methods can be used to polymerize a conjugated diene polymer using an organic alkali metal compound as a polymerization initiator. While not particularly limited, the method may be batch polymerization, continuous polymerization, or a combination thereof. The polymerization temperature is preferably 0°C to 180°C, more preferably 30°C to 150°C. The polymerization time varies depending on the conditions, but is typically within 48 hours, preferably 0.1 to 10 hours. Furthermore, an inert gas atmosphere such as nitrogen gas is preferred as the polymerization atmosphere. The polymerization pressure is not particularly limited, as long as it is set within a pressure range that can maintain the monomer and solvent in a liquid phase within the above temperature range. Furthermore, it is preferable to take care to prevent impurities that may inactivate the catalyst and living polymer, such as water, oxygen, or carbon dioxide, from being introduced into the polymerization system.

[0071] Furthermore, at the end of the polymerization reaction step, a required amount of a bifunctional or higher coupling agent may be added to carry out coupling reaction.As the bifunctional coupling agent, a conventionally known one can be used, and is not limited to the following, for example, alkoxysilane compounds such as trimethoxysilane, triethoxysilane, tetramethoxysilane, tetraethoxysilane, dimethyldimethoxysilane, diethyldimethoxysilane, dichlorodimethoxysilane, dichlorodiethoxysilane, trichloromethoxysilane, trichloroethoxysilane, etc.; dihalogen compounds such as dichloroethane, dibromoethane, dimethyldichlorosilane, dimethyldibromosilane, etc.; acid esters such as methyl benzoate, ethyl benzoate, phenyl benzoate, phthalic acid esters, etc. Furthermore, as the polyfunctional coupling agent having three or more functionalities, conventionally known ones can be used and are not particularly limited. Examples thereof include polyhydric or higher polyalcohols, epoxidized soybean oil, diglycidyl bisphenol A, polyhydric epoxy compounds such as 1,3-bis(N-N'-diglycidylaminomethyl)cyclohexane; ４－ｎ Six ｎ(wherein R is a hydrocarbon group having 1 to 20 carbon atoms, X is a halogen, and n is an integer of 3 to 4), such as methylsilyl trichloride, t-butylsilyl trichloride, silicon tetrachloride, and brominated compounds thereof; ４－ｎ SnX ｎ (wherein R is a hydrocarbon group having 1 to 20 carbon atoms, X is a halogen, and n is an integer of 3 to 4), such as polyvalent halogen compounds such as methyltin trichloride, t-butyltin trichloride, and tin tetrachloride. Dimethyl carbonate, diethyl carbonate, etc. may also be used.

[0072] <Modification Reaction> In the method for producing a hydrogenated conjugated diene copolymer according to the present embodiment, a modified conjugated diene copolymer having an atomic group bonded thereto may be obtained. The atomic group having a functional group is preferably bonded as a step preceding the hydrogenation step described below.

[0073] The "atomic group having a functional group" is not limited to the following, but examples thereof include atomic groups containing at least one functional group selected from a hydroxyl group, a carboxyl group, a carbonyl group, a thiocarbonyl group, an acid halide group, an acid anhydride group, a carboxylic acid group, a thiocarboxylic acid group, an aldehyde group, a thioaldehyde group, a carboxylic acid ester group, an amide group, a sulfonic acid group, a sulfonate ester group, a phosphoric acid group, a phosphoric acid ester group, an amino group, an imino group, a nitrile group, a pyridyl group, a quinoline group, an epoxy group, a thioepoxy group, a sulfide group, an isocyanate group, an isothiocyanate group, a silicon halide group, a silanol group, an alkoxy silicon group, a tin halide group, a boronic acid group, a boron-containing group, a boronate salt group, an alkoxytin group, a phenyltin group, etc. Particularly preferred are atomic groups containing at least one functional group selected from a hydroxyl group, an epoxy group, an amino group, a silanol group, and an alkoxysilane group.

[0074] The "atomic group having a functional group" can be formed by using a modifying agent. Examples of the modifying agent include, but are not limited to, tetraglycidyl meta-xylenediamine, tetraglycidyl-1,3-bisaminomethylcyclohexane, ε-caprolactone, δ-valerolactone, 4-methoxybenzophenone, γ-glycidoxyethyltrimethoxysilane, γ-glycidoxypropyltrimethoxysilane, γ-glycidoxypropyldimethylphenoxysilane, bis(γ-glycidoxypropyl)methylpropoxysilane, 1,3-dimethyl-2-imidazolidinone, 1,3-diethyl-2-imidazolidinone, N,N'-dimethylpropyleneurea, and N-methylpyrrolidone.

[0075] The modified conjugated diene polymer can be obtained, for example, by anionic living polymerization using a polymerization initiator having a functional group or an unsaturated monomer having a functional group, or by addition reaction of a modifier that forms or contains a functional group at the living terminal. Another method involves reacting a conjugated diene polymer with an organic alkali metal compound such as an organolithium compound (metallation reaction), and then adding a modifier having a functional group to the conjugated diene polymer to which the organic alkali metal has been added. In the case of a method using a metallation reaction, a modified hydrogenated conjugated diene copolymer can also be produced by subjecting a hydrogenated conjugated diene polymer to a metallation reaction and then reacting the polymer with a modifier. The temperature at which the modification reaction is carried out is preferably 0 to 150°C, more preferably 20 to 120°C. The time required for the modification reaction varies depending on other conditions, but is preferably within 24 hours, more preferably 0.1 to 10 hours. In such a modified conjugated diene polymer, the modified conjugated diene polymer may contain a part of an unmodified conjugated diene polymer mixed therein.

[0076] The modified conjugated diene copolymer may also be a second-order modified conjugated diene copolymer. The second-order modified conjugated diene copolymer can be obtained by reacting the modified conjugated diene copolymer with a second-order modifier reactive with the functional groups of the modified conjugated diene copolymer. Examples of the second-order modifier include, but are not limited to, modifiers having a functional group selected from a carboxyl group, an acid anhydride group, an isocyanate group, an epoxy group, a silanol group, and an alkoxysilane group, and the second-order modifier has at least two functional groups selected from these functional groups. However, when the functional group of the second-order modifier is an acid anhydride group, the second-order modifier may also have one acid anhydride group. When reacting the modified conjugated diene copolymer with the second-order modifier as described above, the amount of the second-order modifier used is preferably 0.3 to 10 mol, more preferably 0.4 to 5 mol, and even more preferably 0.5 to 4 mol, per equivalent of the functional group bonded to the modified conjugated diene copolymer. The method for reacting the modified conjugated diene copolymer with the secondary modifier can be any known method and is not particularly limited. Examples include the melt-kneading method described below and a method in which the components are dissolved or dispersed and mixed in a solvent or the like and then reacted. It is preferable that these secondary modifications are carried out after the hydrogenation step. Examples of secondary modifiers include, but are not limited to, maleic anhydride, pyromellitic anhydride, 1,2,4,5-benzenetetracarboxylic dianhydride, toluylene diisocyanate, tetraglycidyl-1,3-bisaminomethylcyclohexane, bis-(3-triethoxysilylpropyl)-tetrasulfane, etc.

[0077] Furthermore, in the method for producing the hydrogenated conjugated diene copolymer of this embodiment, a modified conjugated diene copolymer graft-modified with an α,β-unsaturated carboxylic acid or a derivative thereof, such as an anhydride, ester, amidation, or imidation product thereof, may be obtained in step 1. Examples of the α,β-unsaturated carboxylic acid or a derivative thereof include, but are not limited to, maleic anhydride, maleic anhydride imide, acrylic acid or an ester thereof, methacrylic acid or an ester thereof, and endo-cis-bicyclo[2,2,1]-5-heptene-2,3-dicarboxylic acid or anhydride thereof. The amount of the α,β-unsaturated carboxylic acid or a derivative thereof added is preferably 0.01 to 20 parts by mass, more preferably 0.1 to 10 parts by mass, per 100 parts by mass of the hydrogenated conjugated diene copolymer. The reaction temperature for graft modification is preferably 100 to 300°C, more preferably 120 to 280°C. The graft modification method is not limited to the following, but for example, the method described in JP-A-62-79211 can be applied.

[0078] <Hydrogenation Reaction> In the method for producing a hydrogenated conjugated diene polymer according to this embodiment, a non-hydrogenated, unmodified or modified conjugated diene polymer as described above is obtained, and then hydrogenated using the hydrogenation catalyst described above to produce a hydrogenated conjugated diene polymer. The hydrogenation reaction temperature is generally preferably in the range of 0 to 200°C, more preferably in the range of 30 to 150°C. The hydrogen pressure used in the hydrogenation reaction is preferably 0.1 to 15 MPa, more preferably 0.2 to 10 MPa, and even more preferably 0.3 to 5 MPa. The hydrogenation reaction time is generally preferably 3 minutes to 10 hours, more preferably 10 minutes to 5 hours. The hydrogenation reaction may be carried out by a batch process, a continuous process, or a combination thereof. In the method for producing a hydrogenated conjugated diene polymer according to this embodiment, various stabilizers such as phenol-based stabilizers, phosphorus-based stabilizers, sulfur-based stabilizers, and amine-based stabilizers may be added.

[0079] (Step 2) In the method for producing a hydrogenated conjugated diene polymer of this embodiment, step 2 is a step of mixing the metal residue removing agent of this embodiment with the hydrogenated conjugated diene polymer solution. In step 2, the metal residue contained in the hydrogenated conjugated diene polymer solution obtained in step 1 above is sufficiently contacted with the metal residue removing agent of this embodiment to obtain a complex, which makes it easier to separate the metal residue in step 3 described below. As described above, the metal residue removing agent of this embodiment forms a complex with the metal residue and has a TPSA of 138 or less. From the viewpoint of efficiently removing the metal residue in the polymer solution, it is preferable for the metal residue removing agent to have the various structures described above. From the viewpoint of efficiently removing the metal residue in the hydrogenated conjugated diene polymer solution, the mixing time of the metal residue removing agent and the hydrogenated conjugated diene polymer solution is preferably 10 seconds or longer, more preferably 1 minute or longer, even more preferably 5 minutes or longer, and even more preferably 30 minutes or longer. The mixing temperature is preferably 20 to 90°C, more preferably 30 to 80°C, and even more preferably 40 to 70°C, from the viewpoint of efficiently removing metal residues in the hydrogenated conjugated diene polymer solution.

[0080] From the viewpoint of ease of handling, the metal residue removing agent may be liquefied by dissolving or melting it in a solvent, etc., and then added to the hydrogenated conjugated diene polymer solution. For example, by dissolving a solid metal residue removing agent in a solvent, it can be handled as a solution, and by dissolving a liquid metal residue removing agent in a solvent, it can be handled as a solution with reduced viscosity. The solvent for dissolving the metal residue remover is not particularly limited as long as it is a commonly used solvent, and examples thereof include water, methanol, ethanol, 1-propanol, 2-propanol, 1-butanol, 2-butanol, dimethylformamide, dimethyl sulfoxide, acetonitrile, acetone, methyl ethyl ketone, tetrahydrofuran, methyl acetate, ethyl acetate, propyl acetate, butyl acetate, methyl propionate, ethyl propionate, propyl propionate, butyl propionate, chloroform, dichloromethane, carbon disulfide, diethyl ether, n-propyl ether, n-butyl ether, benzene, toluene, o-xylene, m-xylene, p-xylene, cyclohexane, normal hexane, and mixed solvents thereof.

[0081] In step 2, the surfactant may be added. The surfactant is preferably added in an amount of 0 to 0.5 parts by mass relative to 100 parts by mass of the hydrogenated conjugated diene polymer. From the viewpoint of improving the compatibility of the metal residue removing agent with the hydrogenated conjugated diene polymer solution, the amount is preferably 0.001 parts by mass or more, and more preferably 0.01 parts by mass or more. On the other hand, from the viewpoints of economy and suppressing the residue of aliphatic carboxylic acids in the polymer product, the amount is preferably 0.3 parts by mass or less, and more preferably 0.1 parts by mass or less.

[0082] As the surfactant, an anionic surfactant is preferred from the viewpoint of metal residue removal efficiency. As the anionic surfactant, aliphatic carboxylic acids, polycarboxylates, and polyoxyethylene alkyl ether phosphates are preferred from the viewpoint of metal residue removal efficiency. As the aliphatic carboxylic acids, aliphatic carboxylic acids having 8 to 18 carbon atoms are preferred from the viewpoints of economy and ease of handling. As the polycarboxylates, sodium salts of olefin-maleic acid copolymers and sodium salts of styrene-maleic acid copolymers are preferred. As the polyoxyethylene alkyl ether phosphates, polyoxyethylene alkyl ether calcium phosphates are preferred. Among these, aliphatic carboxylic acids having 8 to 18 carbon atoms are more preferred.

[0083] In step 2, the metal residue removing agent of this embodiment is preferably added in an amount of 0.001 to 10 parts by mass per 100 parts by mass of the hydrogenated conjugated diene polymer solution. From the viewpoint of more efficient removal of metal residues, the amount is preferably 0.003 parts by mass or more, more preferably 0.01 parts by mass or more, even more preferably 0.03 parts by mass or more, and even more preferably 0.1 parts by mass or more. On the other hand, from the viewpoints of economy and low residue in the polymer, the amount is preferably 8 parts by mass or less, more preferably 3 parts by mass or less, more preferably 1 part by mass or less, and even more preferably 0.5 parts by mass or less.

[0084] (Step 3) In the method for producing a hydrogenated conjugated diene polymer of this embodiment, step 3 is a step of separating and recovering a hydrogenated conjugated diene polymer by separating the complex obtained in step 2. In step 3, metal residues contained in the hydrogenated conjugated diene polymer solution are separated, and the hydrogenated conjugated diene polymer from which the metal residues have been removed is recovered.

[0085] The method for separating the complex is not particularly limited as long as it is a method commonly used in this field, and examples thereof include extraction into an aqueous layer, extraction into an alcohol layer, adsorption onto a porous solid, filtration, sedimentation, etc. Among these, extraction into an aqueous layer is preferred because it is economical.

[0086] In the method for producing a hydrogenated conjugated diene polymer according to this embodiment, removal of the metal residue is finally completed by separating the hydrogenated conjugated diene polymer from the aqueous phase. The method for separating the hydrogenated conjugated diene polymer from the aqueous phase is not particularly limited as long as it is a method commonly used in the art. Examples of the method include: removing the aqueous phase from a mixture of a hydrogenated conjugated diene polymer solution and an aqueous phase by static separation, centrifugation, countercurrent extraction, or the like, and then drying the hydrogenated conjugated diene polymer solution to recover the hydrogenated conjugated diene polymer; precipitating and recovering the hydrogenated conjugated diene polymer by adding a polar solvent that is a poor solvent for the hydrogenated conjugated diene polymer solution, such as acetone or alcohol; pouring the hydrogenated conjugated diene polymer solution into boiling water with stirring and removing the solvent by steam stripping; and directly heating the hydrogenated conjugated diene polymer solution to remove the solvent. From the viewpoint of economy, the method of removing the solvent by steam stripping and the method of directly heating the hydrogenated conjugated diene polymer solution to distill off the solvent are preferred, and the method of removing the solvent by steam stripping is more preferred.

[0087] [Hydrogenated Conjugated Diene Polymer Composition] The hydrogenated conjugated diene polymer composition of this embodiment contains a hydrogenated conjugated diene polymer, metal residue, and the metal residue removing agent of this embodiment, and the content of the metal residue removing agent is 0.1 to 1000 ppm. From the viewpoint of minimizing the amount of metal residue added and achieving excellent economy, the content of the metal residue removing agent is preferably 300 ppm or less, more preferably 100 ppm or less, even more preferably 30 ppm or less, and even more preferably 10 ppm or less. By adding the metal residue removing agent, the amount of metal residue can be effectively reduced, and the metal residue forms a complex with the metal residue removing agent, thereby effectively reducing the change in the b value of a molded product before and after heating and the haze value of the molded product. The content of the metal residue removing agent in the hydrogenated conjugated diene polymer composition of this embodiment, and the b value and haze value of a sheet-shaped molded product before and after heating can be measured by the methods described in the Examples below.

[0088] The present invention will be described in detail below based on examples, but the present invention is not limited to these examples.

[0089] [Preparation of Hydrogenation Catalyst] The hydrogenation catalyst used in producing the hydrogenated conjugated diene polymer in the examples and comparative examples described below was prepared by the following method.

[0090] (Preparation Example 1) <Preparation of hydrogenation catalyst A> A reaction vessel equipped with a stirrer was purged with nitrogen, and 1 L of dried and purified cyclohexane was charged thereto. Next, 100 mmol of bis(η5-cyclopentadienyl)titanium dichloride was added. While stirring thoroughly, an n-hexane solution containing 200 mmol of trimethylaluminum was added, and the mixture was allowed to react at room temperature for approximately 3 days. This yielded hydrogenation catalyst A.

[0091] (Preparation Example 2) <Preparation of hydrogenation catalyst B> A reaction vessel equipped with a stirrer was purged with nitrogen, and 1 L of dried and purified cyclohexane was charged into the vessel. Next, a cyclohexane solution of nickel (II) 2-ethylhexanoate (100 mmol in terms of Ni) was added. While thoroughly stirring, a cyclohexane solution containing 300 mmol of triethylaluminum was added over 10 minutes, and the mixture was allowed to react at room temperature for 30 minutes. This yielded hydrogenation catalyst B.

[0092] (Preparation Example 3) <Preparation of hydrogenation catalyst C> A reaction vessel equipped with a stirrer was purged with nitrogen, and 1 L of dried and purified cyclohexane was charged thereto. Next, a cyclohexane solution of cobalt (II) neodecanoate (100 mmol in terms of Co) was added. While thoroughly stirring, a cyclohexane solution containing 300 mmol of triethylaluminum was added over 10 minutes, and the mixture was allowed to react at room temperature for 30 minutes. This yielded hydrogenation catalyst C.

[0093] [Preparation of Polymer Solution] (Production Example 1) <Preparation of Polymer Solution 1> Batch polymerization was carried out using a 100 L tank reactor equipped with a stirrer and a jacket in the following manner. First, 45 kg of cyclohexane was charged into the reactor, and the temperature was adjusted to 55°C. After that, 8,000 g of the total amount of butadiene monomer and styrene monomer (hereinafter referred to as "total monomers") charged into the reactor was taken as 100 parts by mass. 0.150 parts by mass of n-butyllithium (hereinafter also referred to as "nBL") and 0.4 moles of N,N,N',N'-tetramethylethylenediamine (hereinafter also referred to as "TMEDA") per mole of nBL were added. Next, 15 parts by mass of styrene were charged over 5 minutes, and the reaction was continued for an additional 15 minutes. Next, a cyclohexane solution (concentration: 40% by mass) containing 70 parts by mass of butadiene was continuously charged into the reactor at a constant rate over 30 minutes, and the reaction was continued for an additional 15 minutes. Next, 15 parts by mass of styrene was added over 5 minutes, and the reaction was continued for another 15 minutes. Three minutes after the reaction temperature reached a maximum of 85°C, 1.0 mole of methanol per mole of nBL was added to terminate the polymerization reaction, yielding a cyclohexane solution (polymer solution 1) with a conjugated diene polymer concentration of 15% by mass. The amount of metal contained in the resulting polymer was measured by elemental analysis using inductively coupled plasma (ICP). The measurement results for the metal residue concentration in the polymer are shown in Table 1 below.

[0094] (Production Example 2) <Preparation of Polymer Solution 2> The hydrogenation catalyst A was added to the polymer solution 1 obtained in (Production Example 1) in an amount of 100 ppm (as titanium) per 100 parts by mass of the conjugated diene polymer, and a hydrogenation reaction was carried out for 45 minutes at a hydrogen pressure of 0.9 MPa and a temperature of 90°C, thereby obtaining a cyclohexane solution (polymer solution 2) having a hydrogenated conjugated diene polymer concentration of 15% by mass. The amount of metal contained in the obtained polymer was measured by elemental analysis using ICP. The measurement results of the metal residue concentration in the polymer are shown in Table 1.

[0095] (Production Example 3) <Preparation of Polymer Solution 3> Hydrogenation catalyst A was changed to hydrogenation catalyst B, and 600 ppm of nickel was added. The hydrogenation reaction was carried out for 480 minutes at a hydrogen pressure of 0.98 MPa and a temperature of 75°C under the same conditions as in (Production Example 2), yielding polymer solution 3. The amount of metal contained in the obtained polymer was measured by elemental analysis using ICP. The measurement results of the concentration of metal residue in the polymer are shown in Table 1.

[0096] (Production Example 4) <Preparation of Polymer Solution 4> Hydrogenation catalyst A was changed to hydrogenation catalyst C, 600 ppm of cobalt was added, and the hydrogenation reaction was carried out for 600 minutes at a hydrogen pressure of 2.0 MPa and a temperature of 150°C under the same conditions as in (Production Example 2), to obtain polymer solution 4. The amount of metal contained in the obtained polymer was measured by elemental analysis using ICP. The measurement results of the concentration of metal residue in the polymer are shown in Table 1.

[0097] (Production Example 5) <Preparation of Polymer Solution 5> The cyclohexane initially charged was changed to a mixed solvent containing 90% by mass of cyclohexane and 10% by mass of n-hexane, and the other conditions were the same as in (Production Example 1), to obtain Polymer Solution 5'. Polymer Solution 1 was changed to Polymer Solution 5', and the other conditions were the same as in (Production Example 2), to obtain Polymer Solution 5. The amount of metal contained in the obtained polymer was measured by elemental analysis using ICP. The measurement results of the concentration of metal residue in the polymer are shown in Table 1.

[0098] (Production Example 6) <Production of Polymer 6> The amount of hydrogenation catalyst A was changed to 20 ppm of titanium per 100 parts by mass of conjugated diene polymer, and the hydrogen pressure during the hydrogenation reaction was changed to 1.5 MPa, the temperature to 50°C, and the time to 240 minutes. The other conditions were the same as in (Production Example 2), and polymer solution 6 was obtained. Using a 10 L internal volume stirrer and a jacketed tank reactor, polymer 6 was produced by the following method. 5000 g of polymer solution 6 was placed in a 10 L reactor and heated to 50°C with stirring. Subsequently, 3.7 mmol (0.10 parts by mass per 100 parts by mass of polymer) of lauric acid was added to the polymer solution, and the mixture was stirred at 50°C for 5 minutes. Thereafter, 150 g of ultrapure water was added, and the mixture was stirred at 50°C for 30 minutes to obtain a polymer solution. A 10 L vessel equipped with a stirrer was charged with 5 kg of 95°C hot water, and 50 g of the mixed solution of the polymer solution and ultrapure water obtained as described above was added over 5 minutes to perform steam stripping. After stirring for 10 minutes, the aggregated polymer crumbs were collected, dehydrated, and vacuum dried to remove moisture, yielding Polymer 6. The amount of metal contained in the resulting polymer was measured by elemental analysis using ICP. The measurement results for the concentration of metal residues in the polymer are shown in Table 1.

[0099]

[0100] [Examples A1 to A29, Comparative Examples A1 to A2: Metal Residue Removers] The metal residue removers used in the examples and comparative examples described below are shown below. Note that the number in brackets [ ] after the compound name indicates that the compound is a compound represented by the above formulas (I) to (III). Compound 1: Ethylene glycol Compound 2: 1,3-propanediol Compound 3: 3-amino-1-propanol Compound 4: 3-(methylamino)-1-propanol Compound 5: 2-(dimethylamino)ethanol Compound 6: 3-(dimethylamino)-1-propanol Compound 7: Ethylene glycol monomethyl ether Compound 8: Hydroxyacetone [(I)] Compound 9: Methyl glycolate [(I)] Compound 10: Diacetyl [(I)] Compound 11: Glyoxal [(I)] Compound 12: 1,3-dihydroxyacetone [(I)] Compound 13: Diethylene glycol Compound 14: Glycerol Compound 15: 3-methoxy-1,2-propanediol Compound 16: 1,2,3-cyclohexanetriol Compound 17: 1,2,6-hexanetriol Compound 18: Diethanolamine Compound 19: 3-(dimethylamino)-1,2-propanediol Compound 20: 1-monoacetin Compound 21: trimethylolmethane [(II)] Compound 22: trimethylolethane [(II)] Compound 23: trimethylolpropane [(II)] Compound 24: triethylene glycol Compound 25: N-(3-aminopropyl)diethanolamine Compound 26: N,N,N',N'-tetrakis(2-hydroxyethyl)ethylenediamine Compound 27: triethanolamine [(III)] Compound 28: diethyl 2-hydroxymalonate Compound 29: diethyl ketomalonate Compound 30: ethylenediaminetetraacetic acid Compound 31: N-hydroxyethylethylenediaminetriacetic acid

[0101] [Properties of Metal Residue Remover] Tables 2 to 4 show the TPSA, polar functional group, minimum O-atom distance, and molecular weight as properties of Compounds 1 to 31. The TPSA row shows the TPSA calculated from the structure of the compound. The polar functional group row shows, when the compound has any of a hydroxy group (excluding hydroxy groups in carboxyl groups), a carbonyl group (excluding carbonyl groups in carboxyl groups), an ether group (excluding ether groups in ester groups), a primary amino group, a secondary amino group, a tertiary amino group, and an imino group, it is represented as a hydroxy group, a carbonyl group, an ether group, a primary amino group, a secondary amino group, a tertiary amino group, and an imino group, respectively. When the compound contains multiple polar functional groups of the same type, the same number of groups are represented. In the row of the minimum inter-O atom distance, when the polar functional group is only a hydroxy group (excluding the hydroxy group in a carboxyl group) or an ether group (excluding the ether group in an ester group), the smallest value among the number of atoms other than O atoms between two O atoms is shown. In the row of the molecular weight, the molecular weight of the compound is shown.

[0102]

[0103]

[0104]

[0105] [Production of Polymer Solution Using Metal Residue Removal Agent] (Example 1) Using a 10 L stirring device and a jacketed tank-type reactor, metal residues were removed from a polymer solution by the following method. 5,000 g of polymer solution 2 obtained in (Production Example 2) above was placed in a 10-liter reactor and heated to 50°C with stirring. Subsequently, 35 mmol of compound 1 was added as a metal residue removal agent, and the mixture was stirred at 50°C for 5 minutes. 150 g of ultrapure water was then added, and the mixture was stirred at 50°C for 30 minutes to obtain a polymer solution. 5 kg of 95°C hot water was charged into a 10 L vessel equipped with a stirring device, and 50 g of a mixed solution of the polymer solution and ultrapure water obtained as described above was added over 5 minutes to perform steam stripping. After stirring for 10 minutes, the aggregated polymer crumbs were collected, and the polymer crumbs were dehydrated and vacuum dried to remove moisture. The amount of metal residue in the polymer obtained after drying was measured by ICP, and the metal residue removal rate (%) in the polymer was calculated. The calculation results of the metal residue removal rate (%) in the polymer are shown in Table 5.

[0106] Examples 2 to 145 Polymers were obtained under the same conditions as in Example 1, except that the type of polymer solution and the type of metal residue removing agent in Example 1 were changed as shown in Tables 5 to 19. The amount of metal residue in the obtained polymer was measured by ICP, and the metal residue removal rate (%) in the polymer was calculated. The calculation results of the metal residue removal rate (%) in the polymer are shown in Tables 5 to 19.

[0107]

[0108]

[0109]

[0110]

[0111]

[0112]

[0113]

[0114]

[0115]

[0116]

[0117]

[0118]

[0119]

[0120]

[0121]

[0122] Examples 146 to 174 Polymers were obtained under the same conditions as in Example 1, except that the type of polymer solution and the type of metal residue removing agent in Example 1 were changed as shown in Tables 20 to 22. The polymer solution was placed in a reactor and heated to 50°C with stirring. Prior to adding the metal residue removing agent, 3.7 mmol (0.10 parts by mass relative to 100 parts by mass of polymer) of lauric acid, an aliphatic carboxylic acid, was added as a surfactant to the polymer solution. The amount of metal residue in the resulting polymer was measured by ICP, and the metal residue removal rate (%) in the polymer was calculated. The calculation results of the metal residue removal rate (%) in the polymer are shown in Tables 20 to 22.

[0123]

[0124]

[0125]

[0126] Examples 175-184 The type of polymer solution and the type of metal residue removing agent used in Example 1 were changed as shown in Tables 23-24, and the surfactants shown in Tables 23-24 were added in the amounts shown in Tables 23-24 simultaneously with the addition of ultrapure water. Polymers were obtained under the same conditions as in Example 1. Surfactant A in Tables 23-24 represents a polyoxyethylene alkyl ether calcium phosphate salt (Phosphanol RL-310, manufactured by Toho Chemical Industry Co., Ltd.), and surfactant B represents a sodium salt of styrene-maleic acid copolymer (XIRAN3500HNa, manufactured by Polyscope Polymers BV). The amount of metal residue in the resulting polymer was measured by ICP, and the metal residue removal rate (%) in the polymer was calculated. The calculation results for the metal residue removal rate (%) in the polymer are shown in Tables 23-24.

[0127]

[0128]

[0129] Comparative Examples 1 and 2 Polymers were obtained in the same manner as in Example 1, except that the type of polymer solution and the type of metal residue removing agent in Example 1 were changed as shown in Table 25. The amount of metal residue in the obtained polymer was measured by ICP, and the metal residue removal rate (%) in the polymer was calculated. The calculation results of the metal residue removal rate (%) in the polymer are shown in Table 25.

[0130]

[0131] The polymers described in the Examples and Comparative Examples in Table 26 were molded into sheets with a thickness of 2 mm, and the change in b value and haze upon heating were measured as follows. The measurement results are shown in Table 26.

[0132] Example 193: 5 g of the polymer from Example 172 was dissolved in 50 g of tetrahydrofuran, and 3.5 mg of compound 27 from Example A27 was added to this polymer solution. The mixture was then vacuum dried to obtain a polymer composition. The content of compound 27 in the polymer composition was 830 ppm. This polymer composition was molded into a 2 mm thick sheet, and the change in b value and haze upon heating were measured as follows. The measurement results are shown in Table 26.

[0133] (Measurement of content of metal residue remover in polymer composition) A polymer composition solution obtained by dissolving 0.1 g of the polymer composition in 10 g of tetrahydrofuran was used as a sample, and measurement was performed using gas chromatography. The analysis conditions were as follows. <Analysis conditions> Apparatus: Agilent 7890A (manufactured by Agilent Technologies Inc.) Detector: FID Column: InertCap for Amines (manufactured by GL Sciences Inc.) Carrier gas: Helium Gas flow rate: 1.7 mL / min Injection port temperature: 250°C Detector temperature: 265°C Oven temperature: After holding at 50°C for 1 minute, the temperature was increased to 265°C in 10 minutes and held for 10 minutes.

[0134] (Measurement of change in b value upon heating) The hydrogenated conjugated diene polymer was compression molded to prepare a sheet-like molded body having a thickness of 2 mm, which was used as a measurement sample. The b value of the sheet-like molded body was measured using a color difference meter (SM-T45 manufactured by Suga Test Instruments Co., Ltd.). The sheet-like molded body was heated at 100°C for 120 minutes in an air atmosphere, cooled to room temperature, and then the b value was measured in the same manner. The change in b value was calculated by subtracting the b value of the sheet-like molded body before heating from the b value of the sheet-like molded body after heating, and the resultant value was evaluated as follows: ◎: Less than 8 ◯: 8 or more but less than 10 △: 10 or more but less than 15 ×: 15 or more

[0135] (Haze Measurement) A hydrogenated conjugated diene polymer was compression molded to prepare a sheet-like molded body having a thickness of 2 mm, which was used as a measurement sample. The haze (%) of the sheet-like molded body was measured using a haze meter (manufactured by Nippon Denshoku Industries Co., Ltd., NDH-8000), and the haze was evaluated according to the value as follows: ◎: Less than 9 ◯: 9 or more but less than 12 △: 12 or more but less than 15 ×: 15 or more

[0136]

[0137] This application is based on a Japanese patent application (Patent Application No. 2024-018631) filed with the Japan Patent Office on February 9, 2024, and an international application (PCT / JP2025 / 001902) filed with the Japan Patent Office, the receiving office, on January 22, 2025, the contents of which are incorporated herein by reference.

[0138] The metal residue remover for polymer solutions and the method for producing polymers using the same of the present invention have industrial applicability as a method for removing catalyst residues remaining in polymer solutions.

Claims

1. A metal residue remover that forms a complex with metal residue when added to a polymer solution containing metal residue, and has a TPSA (Topological Polar Surface Area) of 138 or less.

2. The metal residue remover according to claim 1, which is an organic compound having at least two polar functional groups.

3. The metal residue remover according to claim 2, wherein one of the at least two polar functional groups is selected from the group consisting of a hydroxy group (excluding the hydroxy group in a carboxyl group), a carbonyl group (excluding the carbonyl group in a carboxyl group), an ether group (excluding the ether group in an ester group), a primary amino group, a secondary amino group, a tertiary amino group, and an imino group.

4. A metal residue remover according to claim 1, which has one each of the following functional group 1 and functional group 2, wherein the functional group 1 is any one selected from the group consisting of a hydroxy group (excluding the hydroxy group in a carboxyl group), a carbonyl group (excluding the carbonyl group in a carboxyl group), an ether group (excluding the ether group in an ester group), a primary amino group, a secondary amino group, a tertiary amino group, and an imino group, and the functional group 2 is any one selected from the group consisting of a hydroxy group (excluding the hydroxy group in a carboxyl group), a carbonyl group (excluding the carbonyl group in a carboxyl group), an ether group (excluding the ether group in an ester group), a secondary amino group, and an imino group.

5. A metal residue remover having one each of the following functional group 1 and functional group 2, wherein the functional group 1 is any one selected from the group consisting of a hydroxy group (excluding the hydroxy group in a carboxyl group), a carbonyl group (excluding the carbonyl group in a carboxyl group), an ether group (excluding the ether group in an ester group), a primary amino group, a secondary amino group, a tertiary amino group, and an imino group, and the functional group 2 is any one selected from the group consisting of a carbonyl group (excluding the carbonyl group in a carboxyl group), an ether group (excluding the ether group in an ester group), a secondary amino group, and an imino group, The metal residue remover according to claim 1, wherein when the functional group 1 and the functional group 2 are all any one selected from the group consisting of a hydroxy group (excluding a hydroxy group in a carboxyl group) and an ether group (excluding an ether group in an ester group), three or more atoms other than O atoms are present between any O atom contained in the functional group 1 and the functional group 2 and any other O atom.

6. A metal residue remover according to claim 1, which has three or more of the following functional groups 1, wherein the functional groups 1 are at least one functional group selected from the group consisting of a hydroxy group (excluding the hydroxy group in a carboxyl group), a carbonyl group (excluding the carbonyl group in a carboxyl group), an ether group (excluding the ether group in an ester group), a primary amino group, a secondary amino group, a tertiary amino group, and an imino group.

7. A metal residue remover according to claim 1, which has three of the following functional groups 1, wherein the functional group 1 is at least one functional group selected from the group consisting of a hydroxy group (excluding the hydroxy group in a carboxyl group), a carbonyl group (excluding the carbonyl group in a carboxyl group), an ether group (excluding the ether group in an ester group), a primary amino group, a secondary amino group, a tertiary amino group, and an imino group, and when all of the three functional groups 1 are selected from the group consisting of a hydroxy group (excluding the hydroxy group in a carboxyl group) and an ether group (excluding the ether group in an ester group), there are three or more atoms other than O atoms between any O atom contained in the functional group 1 and any other O atom.

8. A metal residue remover according to claim 1, which has four or more of the following functional groups 1, wherein the functional groups 1 are at least one functional group selected from the group consisting of a hydroxy group (excluding a hydroxy group in a carboxyl group), a carbonyl group (excluding a carbonyl group in a carboxyl group), an ether group (excluding an ether group in an ester group), a primary amino group, a secondary amino group, a tertiary amino group, and an imino group.

9. The metal residue remover according to claim 1, wherein the metal residue is at least one selected from the group consisting of alkali metals, alkaline earth metals, transition metals, and earth metals.

10. The metal residue remover according to claim 1, wherein the metal residue is at least one selected from the group consisting of lithium, nickel, cobalt, titanium, and aluminum.

11. The metal residue remover according to claim 1, wherein the metal residue is at least one selected from the group consisting of nickel, cobalt, and titanium.

12. The metal residue remover according to claim 1, wherein the metal residue is at least one selected from the group consisting of lithium and titanium.

13. The metal residue remover according to claim 1, wherein the metal residue is titanium.

14. The metal residue remover according to claim 1, wherein the polymer solution is a conjugated diene polymer solution.

15. The metal residue remover according to claim 1, wherein the polymer solution is a hydrogenated conjugated diene polymer solution.

16. The metal residue remover according to claim 1, wherein the solvent of the polymer solution is any one selected from the group consisting of cyclohexane, normal hexane, methylcyclohexane, and mixtures thereof.

17. The metal residue remover according to claim 1, wherein the metal residue is titanium originating from a hydrogenation catalyst, and when the metal residue remover is added in an amount of 10 in a molar ratio relative to the titanium constituting the hydrogenation catalyst in the polymer solution, a complex is formed with titanium accounting for 36 mass % or more of the total titanium in the polymer solution.

18. The metal residue remover according to claim 1, wherein the metal residue remover has a structure shown in formula (I) below: (In formula (I), R １ is C(R ３ ) ２ OH, C(R ３ )=O, hydrogen, an alkyl group containing 1 to 3 carbon atoms, and an alkoxy group containing 1 to 3 carbon atoms; ２ is C(R ３ ) ２ OH, and C(R ３ )=O, and R ３ are each independently selected from the group consisting of hydrogen and alkyl groups containing 1 to 3 carbon atoms.

19. The metal residue remover according to claim 1, wherein the metal residue remover has a structure shown in formula (II) below: (In formula (II), R ４ is selected from the group consisting of hydrogen and alkyl groups containing 1 to 3 carbon atoms.

20. The metal residue remover according to claim 1, wherein the metal residue remover has a structure shown in formula (III) below: (In formula (III), R ５ are each independently an alkylene group containing 1 to 4 carbon atoms.

21. The metal residue remover according to claim 1, wherein the molecular weight of the metal residue remover is 250 or less.

22. A metal residue remover system comprising: the metal residue remover according to any one of claims 1 to 21; and a surfactant.

23. The metal residue remover system according to claim 22, wherein the surfactant is an aliphatic carboxylic acid having 8 to 18 carbon atoms.

24. A method for producing a hydrogenated conjugated diene polymer, comprising: Step 1: obtaining a conjugated diene polymer in the presence of a polymerization initiator, and hydrogenating the conjugated diene polymer in the presence of a hydrogenation catalyst to obtain a hydrogenated conjugated diene polymer solution; Step 2: mixing the metal residue remover described in any one of claims 1 to 21 with the hydrogenated conjugated diene polymer solution to obtain a complex; and Step 3: separating the complex to separate and recover the hydrogenated conjugated diene polymer.

25. The method for producing a hydrogenated conjugated diene polymer according to claim 24, wherein in step 2, a surfactant is mixed in an amount of 0.5 parts by mass or less per 100 parts by mass of the hydrogenated conjugated diene polymer.

26. The method for producing a hydrogenated conjugated diene polymer according to claim 25, wherein the surfactant is an aliphatic carboxylic acid having 8 to 18 carbon atoms.

27. The method for producing a hydrogenated conjugated diene polymer according to claim 25, wherein the method for separating the complex in step 3 is extraction into an aqueous layer.

28. The method for producing a hydrogenated conjugated diene polymer according to claim 24, wherein in step 2, the metal residue remover is added in an amount of 0.001 to 10 parts by mass per 100 parts by mass of the hydrogenated conjugated diene polymer solution.

29. A hydrogenated conjugated diene polymer composition comprising a hydrogenated conjugated diene polymer, metal residue, and the metal residue remover according to claim 1, wherein the content of the metal residue remover is 0.1 to 1000 ppm.

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