WO2024080172A1

WO2024080172A1 - Modified group-containing hydrogenated block copolymer and method for producing modified group-containing hydrogenated block copolymer

Info

Publication number: WO2024080172A1
Application number: PCT/JP2023/035800
Authority: WO
Inventors: 亮二小田; 大祐加藤; 篤史野呂; 貴都梶田; 真瑚太田
Original assignee: 日本ゼオン株式会社; 国立大学法人東海国立大学機構
Priority date: 2022-10-14
Filing date: 2023-09-29
Publication date: 2024-04-18

Abstract

Provided is a modified group-containing hydrogenated block copolymer having at least one aromatic vinyl polymer block and at least one modified group-containing hydrogenated conjugated diene polymer block, wherein the modified group-containing hydrogenated conjugated diene polymer block is a hydrogenated conjugated diene polymer block having a unit derived from a conjugated diene monomer into which a modified group capable of non-covalent bonding has been introduced.

Description

Modified group-containing hydrogenated block copolymer and method for producing the modified group-containing hydrogenated block copolymer

The present invention relates to a hydrogenated block copolymer containing a modifying group that has high tensile strength and excellent weather resistance.

Traditionally, thermoplastic elastomers have been used in a variety of fields as elastic materials because they exhibit rubber elasticity at room temperature and become soft and fluid when heated, making them easy to mold and process.

For example, as disclosed in Patent Document 1, some of the present inventors have reported that in an elastomer containing a block copolymer consisting of a hard polymer A in a glassy state near room temperature and a soft polymer B in a molten state near room temperature, by including in polymer B a portion in which a monomer having a functional group capable of non-covalent bonding is polymerized, the monomer components form non-covalent bonds between and within molecules, forming pseudo-crosslinks, thereby exhibiting a large breaking elongation while also exhibiting larger maximum stress, toughness, etc., and thus exhibiting a large elastic limit and high elasticity.

JP 2016-89099 A

There are cases where thermoplastic elastomers are required to have high tensile strength and excellent weather resistance, and there was a demand for elastomers with higher tensile strength and better weather resistance than the elastomer disclosed in Patent Document 1.

The present invention was made in consideration of these circumstances, and aims to provide a hydrogenated block copolymer containing a modifying group that has high tensile strength and excellent weather resistance.

The inventors conducted research and discovered that the above object could be achieved by using a block copolymer having an aromatic vinyl polymer block and a conjugated diene polymer block, among other thermoplastic elastomers, introducing a non-covalently bondable modifying group into the block copolymer, and then hydrogenating the block copolymer, thus completing the present invention.

The present invention provides the following hydrogenated block copolymer containing a modifying group.

[1] A modified group-containing hydrogenated block copolymer having at least one aromatic vinyl polymer block and at least one modified group-containing hydrogenated conjugated diene polymer block,
The modified group-containing hydrogenated conjugated diene polymer block is a hydrogenated conjugated diene polymer block having a unit derived from a conjugated diene monomer to which a non-covalently bondable modified group has been introduced.
[2] The modifying group-containing hydrogenated block copolymer according to [1], wherein the modifying group capable of non-covalent bonding is at least one functional group selected from a functional group capable of hydrogen bonding, a functional group capable of coordinate bonding, and a functional group capable of ionic bonding.
[3] The modifying group-containing hydrogenated block copolymer according to [1] or [2], wherein the non-covalently bondable modifying group has at least one group selected from an ionic group formed of an acid salt, an ionic group formed of a base salt, an acidic group, and a basic group.
[4] The modified group-containing hydrogenated block copolymer according to any one of [1] to [3], wherein the modified group-containing hydrogenated conjugated diene polymer block is a modified group-containing hydrogenated isoprene polymer block, a modified group-containing hydrogenated butadiene polymer block, or a modified group-containing hydrogenated butadiene-isoprene copolymer block.
[5] The modifying group-containing hydrogenated block copolymer according to any one of [1] to [4], wherein the proportion of units derived from an aromatic vinyl monomer is 5 to 50 mass %.
[6] The modifying group-containing hydrogenated block copolymer according to any one of [1] to [5], having a weight average molecular weight of 30,000 to 500,000.
[7] The modifying group-containing hydrogenated block copolymer according to any one of [1] to [6], wherein the hydrogenation rate of the modifying group-containing hydrogenated conjugated diene polymer block is 70 mol % or more.
[8] The modifying group-containing hydrogenated block copolymer according to any one of [1] to [7], wherein an introduction rate of the non-covalently bondable modifying group is 1 to 15 mol % relative to 100 mol % of units derived from a conjugated diene monomer constituting the modifying group-containing hydrogenated conjugated diene polymer block.
[9] The modifying group-containing hydrogenated block copolymer according to any one of [1] to [8], wherein the modifying group-containing hydrogenated conjugated diene polymer block is a hydrogenated conjugated diene polymer block having units derived from a conjugated diene monomer into which the non-covalently bondable modifying group and an ester bond-containing functional group have been introduced.
[10] The modified group-containing hydrogenated block copolymer according to [9], wherein an introduction rate of the ester bond-containing functional group is 0.1 to 30 mol % relative to 100 mol % of units derived from a conjugated diene monomer constituting the modified group-containing hydrogenated conjugated diene polymer block.
[11] The modifying group-containing hydrogenated block copolymer according to any one of claims [1] to [10], wherein the aromatic vinyl polymer block is a polystyrene block.

According to the present invention, there is also provided the following method for producing a modifying group-containing hydrogenated block copolymer.
[12] A method for producing the modifying group-containing hydrogenated block copolymer according to any one of [1] to [11], comprising the steps of:
a modification step of subjecting a base polymer (A1) having at least one aromatic vinyl polymer block and at least one conjugated diene polymer block [D(A1)] to a modification treatment for introducing a non-covalently bondable modifying group, thereby obtaining a modifying group-containing block copolymer (B1) in which at least a portion of units derived from a conjugated diene monomer constituting at least one of the conjugated diene polymer blocks [D(A1)] is a unit derived from a conjugated diene monomer having the non-covalently bondable modifying group; and
A method for producing a modifying group-containing hydrogenated block copolymer, comprising a hydrogenation step of subjecting the modifying group-containing block copolymer (B1) to a hydrogenation treatment.

The present invention provides a hydrogenated block copolymer containing a modifying group that has high tensile strength and excellent weather resistance.

FIG. 1 shows ¹ H-NMR spectra of the raw materials and intermediate products in Example 1 (and the raw materials, intermediate products and final products in Example 2). FIG. 2 is a graph showing the results of gel permeation chromatography (GPC) measurement of the raw materials and intermediate products in Example 1. FIG. 3 is a graph showing the results of transmission Fourier transform infrared absorption spectroscopy (FT-IR) measurement of the raw material, intermediate product, and final product in Example 1. FIG. 4 is a stress-strain curve showing the results of the tensile test in Example 1 and Comparative Example 1. FIG. 5 is a ¹ H-NMR spectrum of the final product in Comparative Example 1. FIG. 6 is a graph showing the results of transmission Fourier transform infrared absorption spectroscopy (FT-IR) measurement of the final product in Comparative Example 1. FIG. 7 is a graph showing the results of gel permeation chromatography (GPC) measurement of the raw materials and the final product in Comparative Example 1. FIG. 8 is a stress-strain curve showing the results of the tensile test in Comparative Example 2. FIG. 9 is a stress-strain curve showing the results of the tensile test in Example 3. FIG. 10 is a stress-strain curve showing the results of the tensile test in Example 2. FIG. 11 is a stress-strain curve showing the results of the tensile test in Example 3.

The modified group-containing hydrogenated block copolymer of the present invention is a modified group-containing hydrogenated block copolymer having at least one aromatic vinyl polymer block and at least one modified group-containing hydrogenated conjugated diene polymer block, and the modified group-containing hydrogenated conjugated diene polymer block is a hydrogenated conjugated diene polymer block having units derived from a conjugated diene monomer to which a non-covalently bondable modified group has been introduced.

The modified group-containing hydrogenated block copolymer of the present invention has high tensile strength and excellent weather resistance. In particular, the modified group-containing hydrogenated block copolymer of the present invention has a high Young's modulus and favorable tensile properties, and has a high retention of tensile properties (particularly the retention of tensile strength and breaking energy) under ultraviolet irradiation.

The modified group-containing hydrogenated block copolymer of the present invention is a copolymer obtained by modifying and hydrogenating the conjugated diene polymer block [D(A1)] in a base polymer (A1) (hereinafter sometimes referred to as "base polymer (A1)") having at least one aromatic vinyl polymer block and at least one conjugated diene polymer block [D(A1)]. In other words, the conjugated diene polymer block [D(A1)] in the above base polymer (A1) is modified and further hydrogenated to form a modified group-containing hydrogenated conjugated diene polymer block.

Specifically, the modifying group-containing hydrogenated block copolymer of the present invention is prepared by subjecting the above-mentioned base polymer (A1) to a modification treatment for introducing a non-covalently bondable modifying group, thereby obtaining a modifying group-containing block copolymer (B1) in which the conjugated diene polymer block [D(A1)] in the base polymer (A1) is converted into a modifying group-containing conjugated diene polymer block [D(B1)] (a conjugated diene polymer block at least partially containing a unit derived from a conjugated diene monomer having a non-covalently bondable modifying group),
The resulting modified group-containing block copolymer (B1) is subjected to a hydrogenation treatment, whereby the modified group-containing conjugated diene polymer block [D(B1)] in the modified group-containing block copolymer (B1) is converted into a modified group-containing hydrogenated conjugated diene polymer block [D(C1)], thereby producing a polymer according to the method for obtaining the modified group-containing hydrogenated block copolymer of the present invention.

In this specification, unless otherwise specified, the term "block copolymer" includes all aspects of a pure block copolymer, a random block copolymer, and a copolymer having a tapered block structure.

Below, we will first explain the base polymer (A1).

<Base polymer (A1)>
The base polymer (A1) has at least one aromatic vinyl polymer block and at least one conjugated diene polymer block [D(A1)].

The aromatic vinyl polymer block of the base polymer (A1) is a polymer block composed mainly of repeating units derived from aromatic vinyl monomers obtained by polymerizing monomers containing aromatic vinyl monomers.

The aromatic vinyl monomer used to form the aromatic vinyl polymer block is not particularly limited as long as it is an aromatic vinyl compound. Examples of aromatic vinyl compounds include styrene; styrenes having alkyl groups as substituents, such as α-methylstyrene, 2-methylstyrene, 3-methylstyrene, 4-methylstyrene, 2-ethylstyrene, 3-ethylstyrene, 4-ethylstyrene, 2,4-diisopropylstyrene, 2,4-dimethylstyrene, 4-t-butylstyrene, and 5-t-butyl-2-methylstyrene; styrenes having ether or ester groups as substituents, such as 4-acetoxystyrene, 4-(1-ethoxyethoxy)styrene, 4-methoxystyrene, 4-ethoxystyrene, and 4-t-butoxystyrene; styrenes having halogen atoms as substituents, such as 2-chlorostyrene, 3-chlorostyrene, 4-chlorostyrene, 4-bromostyrene, and 2,4-dibromostyrene; styrenes having alkyl groups and halogen atoms as substituents, such as 2-methyl-4,6-dichlorostyrene; vinylnaphthalene; and the like. These aromatic vinyl monomers can be used alone or in combination of two or more.

Among these aromatic vinyl compounds, from the viewpoint of ease of availability, styrene, styrenes having an alkyl group with 1 to 12 carbon atoms as a substituent, and styrenes having an ether group or an ester group as a substituent are preferred, with styrene being particularly preferred. In other words, it is preferred that the aromatic vinyl polymer block is a polystyrene block composed of styrene as the main repeating unit.

　As long as the aromatic vinyl polymer block contains units derived from aromatic vinyl monomers as the main repeating units, it may contain other monomer units. Examples of monomers constituting monomer units other than units derived from aromatic vinyl monomers that may be contained in the aromatic vinyl polymer block include conjugated diene monomers such as 1,3-butadiene and isoprene (2-methyl-1,3-butadiene); α,β-unsaturated nitrile monomers such as acrylonitrile and methacrylonitrile; unsaturated carboxylic anhydride monomers such as maleic anhydride, butenyl succinic anhydride, tetrahydrophthalic anhydride and citraconic anhydride; unsaturated carboxylic ester monomers such as methyl acrylate, ethyl acrylate, 2-ethylhexyl acrylate, methyl methacrylate, ethyl methacrylate and 2-ethylhexyl methacrylate; non-conjugated diene monomers preferably having 5 to 12 carbon atoms such as 1,4-pentadiene and 1,4-hexadiene; etc.

The content of units derived from aromatic vinyl monomers in the aromatic vinyl polymer block is preferably 60% by mass or more, more preferably 80% by mass or more, and particularly preferably substantially 100% by mass.

In addition, when the base polymer (A1) has multiple aromatic vinyl polymer blocks, the multiple aromatic vinyl polymer blocks may be the same or different from each other. For example, the multiple aromatic vinyl polymer blocks may contain units derived from the same aromatic vinyl monomer as the main repeating units, or may be different from each other.

The conjugated diene polymer block [D(A1)] contained in the base polymer (A1) is a polymer block composed mainly of repeating units derived from a conjugated diene monomer obtained by polymerizing a monomer containing a conjugated diene monomer.

The conjugated diene monomer used to form the conjugated diene polymer block [D(A1)] is not particularly limited as long as it is a conjugated diene compound. Examples of conjugated diene compounds include 1,3-butadiene, isoprene, 2,3-dimethyl-1,3-butadiene, 2-chloro-1,3-butadiene, 1,3-pentadiene, and 1,3-hexadiene. These conjugated diene monomers can be used alone or in combination of two or more.

Among these, it is preferable to use 1,3-butadiene and/or isoprene. That is, it is preferable that the conjugated diene polymer block [D(A1)] is a butadiene polymer block constituted mainly of repeating units of 1,3-butadiene, an isoprene polymer block constituted mainly of repeating units of isoprene, or a butadiene-isoprene copolymer block constituted mainly of repeating units of 1,3-butadiene and isoprene. Of these, it is more preferable that the conjugated diene polymer block [D(A1)] is an isoprene polymer block. It is preferable that the modified group-containing hydrogenated conjugated diene polymer block [D(C1)] is a modified group-containing hydrogenated isoprene polymer block, a modified group-containing hydrogenated butadiene polymer block, or a modified group-containing hydrogenated butadiene-isoprene copolymer block, and it is more preferable that the modified group-containing hydrogenated isoprene polymer block.

The conjugated diene polymer block [D(A1)] may contain other monomer units as long as the main repeating units are units derived from conjugated diene monomers. Examples of monomers constituting monomer units other than units derived from conjugated diene monomers that may be contained in the conjugated diene polymer block [D(A1)] include aromatic vinyl monomers such as styrene and α-methylstyrene; α,β-unsaturated nitrile monomers; unsaturated carboxylic anhydride monomers; unsaturated carboxylic ester monomers; non-conjugated diene monomers; etc. Specific examples of each monomer may be the same as the monomers constituting monomer units other than units derived from aromatic vinyl monomers that may be contained in the aromatic vinyl polymer block described above.

The content of units derived from a conjugated diene monomer in the conjugated diene polymer block [D(A1)] is preferably 60% by mass or more, more preferably 80% by mass or more, and even more preferably substantially 100% by mass.

In addition, when the base polymer (A1) has multiple conjugated diene polymer blocks [D(A1)], the multiple conjugated diene polymer blocks [D(A1)] may be the same or different from each other. For example, the multiple conjugated diene polymer blocks [D(A1)] may contain units derived from the same conjugated diene monomer as the main repeating units, or may be different from each other.

The vinyl bond content of the conjugated diene polymer block [D(A1)] (the proportion of 1,2-vinyl bonds and 3,4-vinyl bonds in all units derived from conjugated diene monomers in the conjugated diene polymer block [D(A1)]) is not particularly limited, but is preferably within the range of 0.1 to 50 mol %, more preferably within the range of 1 to 30 mol %, and particularly preferably within the range of 3 to 10 mol %. The vinyl bond content of the conjugated diene polymer block [D(A1)] can be measured using ¹ H-NMR.

As long as the base polymer (A1) has at least one aromatic vinyl polymer block and at least one conjugated diene polymer block [D(A1)], there are no particular limitations on the number of polymer blocks or the bond form between them.

Specific examples of the form of the base polymer (A1) include, but are not limited to, an aromatic vinyl-conjugated diene block copolymer represented as Ar-D, an aromatic vinyl-conjugated diene-aromatic vinyl block copolymer represented as Ar-D-Ar or (Ar-D) _n -X, a conjugated diene-aromatic vinyl-conjugated diene block copolymer represented as D-Ar-D or (D-Ar) _n -X, and an aromatic vinyl-conjugated diene-aromatic vinyl-conjugated diene block copolymer represented as Ar-D-Ar-D. Among these, the aromatic vinyl-conjugated diene-aromatic vinyl block copolymer represented as Ar-D-Ar or (Ar-D) _n -X is preferred as the base polymer (A1).

In the above specific examples, the coupling agent can be, for example, an alkoxysilane compound having two or more alkoxy groups per molecule directly bonded to silicon atoms. Specific examples of alkoxysilane compounds include dialkyl dialkoxysilane compounds such as dimethyl dimethoxysilane, dimethyl diethoxysilane, dimethyl dipropoxysilane, dimethyl dibutoxysilane, dimethyl diphenoxysilane, diethyl dimethoxysilane, diethyl diethoxysilane, diethyl dipropoxysilane, diethyl dibutoxysilane, and diethyl diphenoxysilane; monoalkyl trialkoxysilane compounds such as methyl trimethoxysilane, methyl triethoxysilane, methyl tripropoxysilane, methyl tributoxysilane, methyl triphenoxysilane, ethyl trimethoxysilane, ethyl triethoxysilane, ethyl tripropoxysilane, ethyl tributoxysilane, and ethyl triphenoxysilane; tetramethoxysilane, tetraethoxysilane, tetrapropoxysilane, tetrabutoxysilane, tetraphenoxysilane, tetratrimethoxysilane, tetratriethoxysilane, tetrapropoxysilane, tetrabutoxysilane, tetraphenoxysilane, and tetratrimethoxysilane. tetraalkoxysilane compounds such as allyloxysilane; alkenylalkoxysilane compounds such as vinyltrimethoxysilane, vinyltriethoxysilane, vinyltrippropoxysilane, vinyltributoxysilane, vinyltriphenoxysilane, allyltrimethoxysilane, octenyltrimethoxysilane, divinyldimethoxysilane, and styryltrimethoxysilane; arylalkoxysilane compounds such as phenyltrimethoxysilane, phenyltriethoxysilane, phenyltrippropoxysilane, phenyltributoxysilane, and phenyltriphenoxysilane; trimethoxychlorosilane, triethoxychlorosilane, tripropoxychlorosilane, tributoxychlorosilane, triphenoxychlorosilane, dimethoxydichlorosilane, dipropoxydichlorosilane, diphenoxydichlorosilane, methoxytrichlorosilane, ethoxytrichlorosilane, halogenoalkoxysilane compounds such as propoxytrichlorosilane, phenoxytrichlorosilane, trimethoxybromosilane, triethoxybromosilane, tripropoxybromosilane, triphenoxybromosilane, dimethoxydibromosilane, diethoxydibromosilane, diphenoxydibromosilane, methoxytribromosilane, ethoxytribromosilane, propoxytribromosilane, phenoxytribromosilane, trimethoxyiodosilane, triethoxyiodosilane, tripropoxyiodosilane, triphenoxyiodosilane, dimethoxydiiodosilane, diethoxydiiodosilane, dipropoxyiodosilane, methoxytriiodosilane, ethoxytriiodosilane, propoxytriiodosilane, and phenoxytriiodosilane; halogenoalkylsilane compounds such as β-chloroethylmethyldimethoxysilane and γ-chloropropylmethyldimethoxysilane; Alkoxysilane compounds include hexamethoxydisilane, hexaethoxydisilane, bis(trimethoxysilyl)methane, bis(triethoxysilyl)methane, bis(trimethoxysilyl)ethane, bis(triethoxysilyl)ethane, bis(trimethoxysilyl)propane, bis(triethoxysilyl)propane, bis(trimethoxysilyl)butane, bis(triethoxysilyl)butane, bis(trimethoxysilyl)heptane, bis(triethoxysilyl)heptane, bis(trimethoxysilyl)hexane, bis(triethoxysilyl)hexane, bis(trimethoxysilyl)benzene, bis(triethoxysilyl)benzene, bis(trimethoxysilyl)benzene, bis(trimethoxysilyl)cyclohexane, bis(triethoxysilyl)cyclohexane, bis(triethoxysilyl)benzene, and bis(3-triethoxysilylpropyl)ethane.

Among these, alkoxysilane compounds in which the functional group that reacts with the active terminal of the polymer is only an alkoxy group are preferably used. Specifically, dialkyldialkoxysilane compounds, monoalkyltrialkoxysilane compounds, and tetraalkoxysilane compounds are more preferably used, and tetraalkoxysilane compounds are particularly preferably used. By using such alkoxysilane compounds as coupling agents, it is possible to achieve high levels of both fatigue resistance and impact resistance.

Furthermore, examples of coupling agents that can be used include bifunctional halogenated silanes such as dichlorosilane, monomethyldichlorosilane, and dimethyldichlorosilane; bifunctional halogenated alkanes such as dichloroethane, dibromoethane, methylene chloride, and dibromomethane; and bifunctional tin halides such as dichlorotin, monomethyldichlorotin, dimethyldichlorotin, monoethyldichlorotin, diethyldichlorotin, monobutyldichlorotin, and dibutyldichlorotin.

These coupling agents may be used alone or in combination of two or more.

The weight average molecular weight of the base polymer (A1) is not particularly limited, but is usually 30,000 to 500,000, preferably 60,000 to 470,000, and more preferably 90,000 to 450,000.

The weight average molecular weight of each polymer block of the base polymer (A1) is not particularly limited. The weight average molecular weight of the aromatic vinyl polymer block is preferably in the range of 3,000 to 50,000, more preferably in the range of 6,000 to 20,000. The weight average molecular weight of the conjugated diene polymer block [D(A1)] is preferably in the range of 10,000 to 500,000, more preferably in the range of 40,000 to 400,000.

The molecular weight distribution, expressed as the ratio (Mw/Mn) of the weight average molecular weight (Mw) to the number average molecular weight (Mn) of the base polymer (A1) and each of the polymer blocks constituting the base polymer (A1), is not particularly limited, but is usually 1.8 or less, preferably 1.3 or less, and more preferably 1.1 or less.

The weight average molecular weight (Mw) and number average molecular weight (Mn) of the base polymer (A1) are determined as polystyrene equivalent values by measurement using high performance liquid chromatography with tetrahydrofuran (THF) as a solvent.

The content of units derived from aromatic vinyl monomers in the total monomer units of the base polymer (A1) is not particularly limited, but is usually selected within the range of 5 to 90 mass%, preferably 10 to 60 mass%. The content of units derived from conjugated diene monomers in the total monomer units of the base polymer (A1) is not particularly limited, but is usually selected within the range of 10 to 95 mass%, preferably 40 to 90 mass%. The content of units derived from the above monomers in the base polymer (A1) can be measured using ¹ H-NMR.

The melt index of the base polymer (A1) is not particularly limited, but is usually 1 to 1000 g/10 min, preferably 3 to 700 g/10 min, and more preferably 5 to 500 g/10 min, as measured in accordance with ASTM D-1238 (G condition, 200°C, 5 kg).

In the present invention, it is also possible to use commercially available block copolymers as the base polymer (A1). For example, "Quintac (registered trademark)" (manufactured by Zeon Corporation), "JSR-SIS (registered trademark)" (manufactured by JSR Corporation), "Vector (registered trademark)" (manufactured by DEXCO Polymers Corporation), "Asaprene (registered trademark)" (manufactured by Asahi Kasei Chemicals Corporation), "Tufprene (registered trademark)" (manufactured by Asahi Kasei Chemicals Corporation), "Tuftec (registered trademark)" (manufactured by Asahi Kasei Chemicals Corporation), "Septon (registered trademark)" (manufactured by Kuraray Co., Ltd.), "Kraton (registered trademark)" (Kraton JSR Elastomers Co., Ltd.), etc. can be used.

<Modifying Group-Containing Block Copolymer (B1)>
The modifying group-containing block copolymer (B1) is a polymer obtained by subjecting the above-mentioned base polymer (A1) to a modification treatment for introducing a modifying group capable of non-covalent bonding, thereby converting the conjugated diene polymer block [D(A1)] in the base polymer (A1) into a modifying group-containing conjugated diene polymer block [D(B1)].

(Non-covalently bondable modifying groups)
The non-covalently bondable modified group (hereinafter sometimes referred to as "modified group") is a functional group capable of forming a physical bond other than a covalent bond, and examples of such functional groups include a functional group capable of hydrogen bonding, a functional group capable of coordinate bonding, and a functional group capable of ionic bonding (hereinafter sometimes referred to as "ionic group"). As the modified group, an ionic group and a functional group capable of hydrogen bonding are preferred, and at least one group selected from an ionic group formed of an acid salt, an ionic group formed of a base salt, an acidic group, and a basic group is more preferred.

The modifying group-containing block copolymer (B1) may have the above-mentioned modifying group, and the modifying group may be bonded, for example, directly to the modifying group-containing block copolymer (B1) or may be bonded via a linking group.

Functional groups capable of forming hydrogen bonds include acidic groups such as carboxyl groups, sulfonic acid groups, and phosphonic acid groups; basic groups such as amino groups, pyridinyl groups, imidazolium groups, and pyrazole groups; amide groups, imide groups, urethane bonds, and hydroxyl groups. Among these, acidic groups and basic groups are preferred, acidic groups are more preferred, and carboxyl groups are even more preferred.

The term "ionic group" refers to a functional group capable of generating ionic interactions and capable of forming ionic bonds. Among non-covalent bonds, ionic interactions have a strong binding force, and therefore the effect of the modifying group can be exerted more effectively when the modifying group-containing block copolymer (B1) has an ionic group as the modifying group. Furthermore, when the modifying group contains an ionic group, the effect of the modifying group can be exerted more effectively, and therefore sufficient effect can be obtained even when the introduction rate of the ionic group is relatively small.

From the viewpoint of ease of introduction, the ionic group is preferably an ionic group generated by mixing an Arrhenius acid and an Arrhenius base and neutralizing the mixture, and/or an ionic group generated by mixing a Bronsted acid and a Bronsted base and neutralizing the mixture.

Specific examples of such ionic groups include ionic groups of acid salts, such as ionic groups of carboxylic acid salts, ionic groups of sulfonic acid salts, and ionic groups of phosphonic acid salts; ionic groups of salts formed by anions obtained by removing protons from the hydroxyl groups of alcohol; ionic groups of base salts, such as ionic groups of amine salts, ionic groups of pyridine salts, ionic groups of imidazole salts, and ionic groups of pyrazole salts. Examples of acid salts include alkali metal salts, alkaline earth metal salts, ammonium salts, pyridinium salts, and imidazolium salts, and among these, alkali metal salts such as sodium salts, lithium salts, and potassium salts, and alkaline earth metal salts such as magnesium salts, calcium salts, and barium salts are preferred. Examples of base salts include carboxylates, sulfonates, phosphonates, and phosphates. Among these, from the viewpoint of ease of introduction, the ionic group is preferably an ionic group formed from an acid salt or an ionic group formed from a base salt, more preferably an ionic group formed from an acid salt, and even more preferably an ionic group formed from a carboxylic acid salt.

The method for introducing a non-covalently bondable modifying group may be any method capable of introducing a modifying group into the conjugated diene polymer block [D(A1)] in the base polymer (A1), and examples of such methods include a modification method using a modifying agent and a method using a functional group conversion reaction of an alkene. Among these, a modification method using a modifying agent is preferred. In other words, the modifying group preferably contains a residue of a modifying agent. Here, the modifying group may be composed of residues of one or more modifying agents.

In addition, when a modification method using a modifying agent is used, the modifying group may be introduced by modification with the modifying agent, or the modifying group may be introduced by further reaction after modification with the modifying agent.

The term "residue of a modifying agent" refers to the portion derived from the modifying agent in the reaction product produced when the modifying agent reacts with the base polymer (A1), or in the reaction product produced when the modifying agent reacts with the base polymer (A1) and then with another compound.

The modifying agent used to introduce the modifying group may be, for example, an Arrhenius acid and/or a Bronsted acid (acid modifying agent). Specific examples include unsaturated carboxylic acids, unsaturated dicarboxylic acid anhydrides, unsaturated phosphonic acids and their acid anhydrides, unsaturated phosphoric acids and their acid anhydrides, unsaturated sulfonic acids and their acid anhydrides, etc.

Unsaturated carboxylic acids used to introduce modifying groups include, for example, ethylenically unsaturated carboxylic acids having 8 or less carbon atoms, such as acrylic acid, methacrylic acid, crotonic acid, maleic acid, fumaric acid, itaconic acid, and citraconic acid, as well as Diels-Alder adducts of conjugated dienes and α,β-unsaturated dicarboxylic acids having 8 or less carbon atoms, such as 3,6-endomethylene-1,2,3,6-tetrahydrophthalic acid.

Unsaturated dicarboxylic anhydrides used to introduce modifying groups include, for example, α,β-unsaturated dicarboxylic anhydrides with 8 or less carbon atoms, such as maleic anhydride, itaconic anhydride, and citraconic anhydride, as well as Diels-Alder adducts of conjugated dienes and α,β-unsaturated dicarboxylic anhydrides with 8 or less carbon atoms, such as 3,6-endomethylene-1,2,3,6-tetrahydrophthalic anhydride.

Among these, from the standpoint of ease of reaction, economy, etc., unsaturated dicarboxylic acid anhydrides are preferred, α,β-unsaturated aliphatic dicarboxylic acid anhydrides having 8 or less carbon atoms are more preferred, and maleic anhydride is particularly preferred. In other words, the modifying group preferably has a residue of an unsaturated dicarboxylic acid anhydride, more preferably has a residue of an α,β-unsaturated aliphatic dicarboxylic acid anhydride having 8 or less carbon atoms, and even more preferably has a residue of maleic anhydride.

When the acid modifier is an unsaturated dicarboxylic anhydride, an acid anhydride group derived from the unsaturated dicarboxylic anhydride is introduced into the conjugated diene polymer block [D(A1)] in the base polymer (A1). For example, when the acid modifier is maleic anhydride, a succinic anhydride unit derived from maleic anhydride is introduced into the conjugated diene polymer block [D(A1)] in the base polymer (A1).

After modification with an unsaturated dicarboxylic acid anhydride as an acid modifier, further reaction can be carried out to convert the acid anhydride group into a non-covalently bondable modified group. Specifically, the acid anhydride group can be converted into a modified group by reacting the acid anhydride group with a base, by hydrolyzing the acid anhydride group with a base, or by subjecting the acid anhydride group to an acyl substitution reaction with an acyl-substituting compound (alcohol, amine, etc.).

Among them, the method of introducing the modified group is preferably a method of modifying the polymer using an unsaturated dicarboxylic anhydride as an acid modifying agent, and then subjecting the acid anhydride group to an acyl substitution reaction with an acyl-substituting compound to introduce a non-covalently bondable functional group. The acyl substitution reaction produces an acyl group-containing group (a group formed by acyl-substituting a carboxyl group with an acyl-substituting compound, for example, an ester bond-containing group or an amide bond-containing group). During the acyl substitution reaction between the acid anhydride group and the acyl-substituting compound, the acid anhydride group usually also reacts with a trace amount of water present in the system to produce a carboxyl group. Through such an acyl substitution reaction, the modified group-containing block copolymer (B1) has units derived from the conjugated diene monomer into which an acyl group-containing group and a carboxyl group have been introduced.

Here, examples of acyl-substituting compounds used in the acyl substitution reaction include alcohols such as 1-butanol, 4-methoxyphenethyl alcohol, and 4,4,4-trifluoro-1-butanol; amines such as n-butylamine; and the like.

When an alcohol is used as the acyl-substituting compound, the modified group-containing block copolymer (B1) has an ester bond-containing group as the acyl group-containing group (a group formed by acyl-substitution of a carboxyl group with an alcohol) and a unit derived from a conjugated diene monomer into which a carboxyl group has been introduced.

When an amine is used as the acyl-substituting compound, the modified group-containing block copolymer (B1) has an amide bond-containing group as the acyl group-containing group (a group formed by acyl-substitution of a carboxyl group with an amine) and a unit derived from a conjugated diene monomer into which a carboxyl group has been introduced.

The modified group-containing block copolymer (B1) preferably has units derived from a conjugated diene monomer into which an acyl group-containing group and a carboxyl group have been introduced. As the acyl group-containing group, an ester bond-containing group and an amide bond-containing group are preferred, and an ester bond-containing group is more preferred because it allows the hydrogenation treatment described below to be carried out more suitably and further improves the tensile strength and weather resistance of the modified group-containing hydrogenated block copolymer of the present invention. In other words, it is preferred that the modified group-containing conjugated diene polymer block [D(B1)] in the modified group-containing block copolymer (B1) has units derived from a conjugated diene monomer into which the non-covalently bondable modified group and ester bond-containing functional group have been introduced.

When the modifying group is introduced by subjecting the acid anhydride group introduced into the base polymer (A1) to an acyl substitution reaction with an acyl-substituting compound, it is sufficient that at least a portion of the acid anhydride group introduced into the base polymer (A1) reacts with the acyl-substituting compound, and a portion of the acid anhydride group may react with the acyl-substituting compound, or all of the acid anhydride group may react with the acyl-substituting compound. In other words, the modifying group-containing block copolymer (B1) may have both a group formed by reacting the acid anhydride group introduced into the base polymer (A1) with the acyl-substituting compound and an acid anhydride group introduced into the base polymer (A1).

Furthermore, after modification with an acid modifying agent, further reaction can be carried out to introduce a non-ionic modifying group (e.g., a carboxyl group), and then the non-ionic modifying group can be converted into an ionic group by further treating with a base. The base treatment of the non-ionic modifying group may be carried out after the hydrogenation treatment described below.

Specifically, the ionic group is preferably any one of the following: a group formed by reacting a carboxyl group derived from an acid modifier with a base (hereinafter referred to as the first base); a group formed by reacting an acid anhydride group derived from an acid modifier with a base (hereinafter referred to as the second base) to form a carboxyl group, which is further reacted with a base (hereinafter referred to as the third base); a group formed by hydrolyzing an acid anhydride group derived from an acid modifier to form a carboxyl group, which is further reacted with a base (hereinafter referred to as the fourth base); or a group formed by subjecting an acid anhydride group derived from an acid modifier to an acyl substitution reaction with an acyl-substituting compound to form a carboxyl group, which is further reacted with a base (hereinafter referred to as the fifth base).

Specific examples of groups formed by reacting a carboxyl group with a first base, a third base, a fourth base, or a fifth base include ionic groups consisting of salts of carboxylic acids.Specific examples of groups formed by reacting an acid anhydride group with a second base include amide groups and carboxyl groups.Specific examples of groups formed by hydrolyzing an acid anhydride group include carboxyl groups.Specific examples of groups formed by the acyl substitution reaction of an acid anhydride group with an acyl-substituting compound include acyl-group-containing groups and carboxyl groups.

When the ionic group is a group formed by reacting a carboxyl group derived from an acid modifier with a first base, it is sufficient that at least a portion of the carboxyl group derived from the acid modifier is reacted with the first base, and a portion of the carboxyl group may react with the first base, or all of the carboxyl group may react with the first base. In other words, the modifying group-containing block copolymer (B1) may have both a group formed by reacting a carboxyl group derived from an acid modifier with a first base, and a carboxyl group derived from an acid modifier.

In addition, when the ionic group is a group formed by reacting a carboxyl group formed by reacting an acid anhydride group derived from an acid modifier with a second base, the acid anhydride group derived from the acid modifier may be at least partially reacted with the second base, a part of the acid anhydride group may be reacted with the second base, or all of the acid anhydride group may be reacted with the second base. Similarly, the carboxyl group formed by the reaction of an acid anhydride group with a second base may be at least partially reacted with a third base, a part of the carboxyl group may be reacted with the third base, or all of the carboxyl group may be reacted with the third base. That is, the modified group-containing block copolymer (B1) may have, for example, a group formed by reacting a carboxyl group formed by reacting an acid anhydride group derived from an acid modifier with a second base, the acid anhydride group derived from an acid modifier, and a group formed by reacting an acid anhydride group derived from an acid modifier with a second base.

In addition, when the ionic group is a group formed by further reacting a carboxyl group formed by hydrolyzing an acid anhydride group derived from an acid modifier with a quaternary base, at least a part of the acid anhydride group derived from the acid modifier may be hydrolyzed, a part of the acid anhydride group may be hydrolyzed, or the entire acid anhydride group may be hydrolyzed. Similarly, at least a part of the carboxyl group formed by hydrolyzing an acid anhydride group derived from an acid modifier may react with a quaternary base, a part of the carboxyl group may react with a quaternary base, or the entire carboxyl group may react with a quaternary base. That is, the modifying group-containing block copolymer (B1) may have, for example, a group formed by further reacting a carboxyl group formed by hydrolyzing an acid anhydride group derived from an acid modifier with a quaternary base, an acid anhydride group introduced into the base polymer (A1), and a group formed by hydrolyzing an acid anhydride group derived from an acid modifier.

In addition, when the ionic group is a group formed by further reacting a carboxyl group formed by the acyl substitution reaction of an acid anhydride group derived from an acid modifier with an acyl-substituting compound with a fifth base, at least a part of the acid anhydride group derived from the acid modifier may react with the acyl-substituting compound, a part of the acid anhydride group may react with the acyl-substituting compound, or all of the acid anhydride group may react with the acyl-substituting compound. Similarly, at least a part of the carboxyl group formed by the acyl substitution reaction may react with the fifth base, a part of the carboxyl group may react with the fifth base, or all of the carboxyl group may react with the fifth base. That is, the modified group-containing block copolymer (B1) may have, for example, a group formed by further reacting a carboxyl group formed by the acyl substitution reaction of an acid anhydride group derived from an acid modifier with an acyl-substituting compound with a fifth base, an acid anhydride group derived from an acid modifier, and a group formed by the acyl substitution reaction of an acid anhydride group derived from an acid modifier with an acyl-substituting compound.

The unsaturated carboxylic acids and unsaturated dicarboxylic anhydrides used to introduce the ionic groups are as described above. In terms of ease of reaction and economic efficiency, unsaturated dicarboxylic anhydrides are preferred, α,β-unsaturated aliphatic dicarboxylic anhydrides having 8 or less carbon atoms are more preferred, and maleic anhydride is even more preferred.

The first base, third base, fourth base, and fifth base may be any base capable of reacting with a carboxyl group to generate the ionic group, and an Arrhenius base and/or a Bronsted base may be used, such as a metal-containing compound, ammonia, an amine compound, pyridine, or imidazole.

Among them, the first base, the third base, the fourth base, and the fifth base are preferably at least one selected from the group consisting of alkali metal-containing compounds and alkaline earth metal-containing compounds, from the viewpoint of being able to stably generate the above-mentioned ionic group. Examples of the alkali metal-containing compounds include alkoxides, oxides, hydroxides, carbonates, hydrogen carbonates, acetates, sulfates, phosphates, etc. of alkali metals such as sodium, lithium, potassium, etc. Examples of the alkaline earth metal-containing compounds include alkoxides, oxides, hydroxides, carbonates, hydrogen carbonates, acetates, sulfates, phosphates, etc. of alkaline earth metals such as magnesium, calcium, barium, etc.

The second base may be any base capable of reacting with an acid anhydride group to generate a carboxyl group, and may be, for example, at least one selected from the group consisting of ammonia and amine compounds. The amine compound may be either a primary amine compound or a secondary amine compound. The amine compound may be either a monoamine or a diamine, but monoamines are preferably used because they are easily available. Examples of amine compounds include aliphatic amines, aromatic amines, alicyclic amines, and heterocyclic amines. Among these, aliphatic amines are preferred, and in particular, alkylamines having 1 to 12 carbon atoms are preferred, with alkylamines having 2, 4, or 6 carbon atoms being more preferred.

As the ionic group, a group obtained by further reacting a carboxyl group formed by an acyl substitution reaction between an acid anhydride group derived from an acid modifier and an acyl-substituting compound with a fifth base is preferred. In this case, the modified group-containing block copolymer (B1) has an ionic group consisting of a carboxylic acid salt and a unit derived from a conjugated diene monomer into which an acyl group-containing group has been introduced.

(Modifying Group Introduction Rate)
The introduction rate of the modifying group (non-covalently bondable modifying group) in the modifying group-containing block copolymer (B1) is not particularly limited, but can be 0.3 mol% to 50 mol% in 100 mol% of the units derived from the conjugated diene monomer in the modifying group-containing block copolymer (B1), preferably 0.5 mol% to 30 mol%, more preferably 1 mol% to 15 mol%, even more preferably 2 mol% to 12 mol%, and particularly preferably 4 mol% to 10 mol%. By setting the introduction rate of the modifying group in the above range, it is possible to effectively prevent stress from concentrating on the physical crosslinking points before rearrangement of the modifying group occurs, which makes the crosslinking prone to breakage, while appropriately enhancing the introduction effect of the modifying group. The introduction rate of the modifying group can be calculated using ¹ H-NMR. The introduction of the modifying group can be confirmed by ¹ H-NMR and/or infrared spectroscopy.

The introduction rate of the ionic group in the modified group-containing block copolymer (B1) can be 0 mol% to 50 mol% out of 100 mol% of units derived from the conjugated diene monomer in the modified group-containing block copolymer (B1), and is preferably 0.5 mol% to 30 mol%, more preferably 1 mol% to 15 mol%, even more preferably 2 mol% to 10 mol%, and particularly preferably 3 mol% to 6 mol%.

The introduction rate of functional groups capable of hydrogen bonding in the modified group-containing block copolymer (B1) can be 0 mol % to 50 mol %, preferably 0.1 mol % to 30 mol %, more preferably 0.3 mol % to 15 mol %, and even more preferably 0.5 mol % to 10 mol %, out of 100 mol % of units derived from the conjugated diene monomer in the modified group-containing block copolymer (B1).

When the modifying group is the ionic group, the molar ratio of the ionic group to the nonionic modifying group (among the non-covalently bondable modifying groups, groups other than ionic groups, for example, functional groups capable of hydrogen bonding) in the modifying group-containing block copolymer (B1) (ionic group/nonionic modifying group) is preferably within the range of 0.1/99.9 to 100/0, more preferably within the range of 1/99 to 99/1, even more preferably within the range of 20/80 to 97/3, particularly preferably within the range of 50/50 to 90/10, and most preferably within the range of 65/35 to 85/15. The molar ratio can be calculated using ¹ H-NMR and/or infrared spectroscopy.

The introduction rate of the acyl group-containing group in the modified group-containing block copolymer (B1) can be 0 mol% to 50 mol% in 100 mol% of the units derived from the conjugated diene monomer in the modified group-containing block copolymer (B1), and is preferably 0.1 mol% to 30 mol%, more preferably 0.3 mol% to 15 mol%, and even more preferably 0.5 mol% to 5 mol%. For example, it is preferable that the introduction rate of the ester bond-containing group as the acyl group-containing group is within the above range. In addition, when the modified group-containing block copolymer (B1) has an acyl group-containing group, the molar ratio of the acyl group-containing group to the modified group (non-covalently bondable modified group) in the modified group-containing block copolymer (B1) (acyl group-containing group/modified group) is preferably within the range of 10/99 to 50/50, more preferably within the range of 15/85 to 45/55, and even more preferably within the range of 20/80 to 40/60. For example, it is preferable that the molar ratio of the ester bond-containing group to the modified group (non-covalently bondable modified group) (ester bond-containing group/modified group) be within the above range.

<Modifying Group-Containing Hydrogenated Block Copolymer>
The modifying group-containing hydrogenated block copolymer of the present invention is a polymer obtained by hydrogenating the modifying group-containing conjugated diene polymer block [D(B1)] in the above-mentioned modifying group-containing block copolymer (B1).

The modified group-containing hydrogenated block copolymer of the present invention may be, for example, a polymer obtained by hydrogenating a modified group-containing block copolymer (B1) having a carboxyl group. The modified group-containing hydrogenated block copolymer of the present invention may also be a polymer obtained by hydrogenating a modified group-containing block copolymer (B1) having a carboxyl group, and then further treating the carboxyl group with a base to generate an ionic group consisting of a salt of a carboxylic acid as the modified group.

The modified group-containing hydrogenated block copolymer has a functional group introduced into the modified group-containing block copolymer (B1), or has a functional group obtained by further reacting the functional group introduced into the modified group-containing block copolymer (B1). For example, when the modified group-containing block copolymer (B1) has a carboxyl group, the modified group-containing hydrogenated block copolymer has a carboxyl group or has an ionic group consisting of a salt of a carboxylic acid. Also, for example, when the modified group-containing block copolymer (B1) has a carboxyl group and an acyl group-containing functional group, the modified group-containing hydrogenated block copolymer has a carboxyl group and an acyl group-containing functional group, or has an ionic group consisting of a salt of a carboxylic acid and an acyl group-containing functional group.

The introduction rate of each functional group in the modified group-containing hydrogenated block copolymer is usually the same as the introduction rate of each functional group in the modified group-containing block copolymer (B1). The preferred ranges of the introduction rates of the modified group and ionic group in the modified group-containing hydrogenated block copolymer are also the same as the ranges described above.

The hydrogenation rate of the modified group-containing hydrogenated block copolymer is not particularly limited, but is preferably 50 mol% or more, and more preferably 70 mol% or more. The hydrogenation rate of the modified group-containing hydrogenated block copolymer may be, for example, 90 mol% or more, or 98 mol% or more. The upper limit of the hydrogenation rate of the modified group-containing hydrogenated block copolymer is not particularly limited, and may be substantially 100 mol% or 99.9 mol% or less. By setting the hydrogenation rate within the above range, the tensile strength and weather resistance can be further improved. Here, the hydrogenation rate refers to the proportion (mol%) of hydrogenated non-aromatic carbon-carbon double bonds contained in the polymer component (modified group-containing block copolymer (B1)) before hydrogenation.

The weight average molecular weight of the modified group-containing hydrogenated block copolymer is not particularly limited, but is preferably 30,000 to 500,000, and more preferably 50,000 to 400,000. By setting the weight average molecular weight of the modified group-containing hydrogenated block copolymer within the above range, the tensile strength and weather resistance can be further improved.

The weight average molecular weight (Mw) of the modified group-containing hydrogenated block copolymer is determined as a polystyrene-equivalent value by measurement using high performance liquid chromatography with tetrahydrofuran (THF) as a solvent.

The content of the units derived from the aromatic vinyl monomer in the total monomer units of the modified group-containing hydrogenated block copolymer is not particularly limited, but is usually selected within the range of 5 to 50 mass%, preferably 10 to 35 mass%. By setting the content of the units derived from the aromatic vinyl monomer in the modified group-containing hydrogenated block copolymer within the above range, the tensile strength and weather resistance can be further improved. The content of the units derived from the aromatic vinyl monomer in the modified group-containing hydrogenated block copolymer can be measured using ¹ H-NMR.

<Method for producing hydrogenated block copolymer containing modifying group>
The modifying group-containing hydrogenated block copolymer of the present invention includes a modification step of subjecting the above-mentioned base polymer (A1) to a modification treatment for introducing a non-covalently bondable modifying group to obtain a modifying group-containing block copolymer (B1) in which at least a portion of units derived from a conjugated diene monomer constituting at least one conjugated diene polymer block [D(A1)] is a unit derived from a conjugated diene monomer having a modifying group; and
The modified group-containing block copolymer (B1) thus obtained can be obtained by a production method including a hydrogenation step in which the modified group-containing block copolymer (B1) is subjected to a hydrogenation treatment. By such a production method, the conjugated diene polymer block [D(A1)] in the base polymer (A1) becomes a modified group-containing conjugated diene polymer block [D(B1)] through the modification step, and further becomes a modified group-containing hydrogenated conjugated diene polymer block [D(C1)] through the hydrogenation step, thereby obtaining the modified group-containing hydrogenated block copolymer of the present invention.

Among them, the following manufacturing method is preferred as the manufacturing method of the hydrogenated block copolymer containing a modifying group of the present invention.

That is, a first step (first modification step) of reacting a base polymer (A1) with an unsaturated dicarboxylic acid anhydride as an acid modifier to obtain a block copolymer (A2) in which an acid anhydride group is introduced into at least a part of the conjugated diene polymer block [D(A1)] in the base polymer (A1) to form an acid anhydride group-containing conjugated diene polymer block [D(A2)];
a second step (second modification step) of reacting the block copolymer (A2) with an acyl-substituting compound to obtain a modifying group-containing block copolymer (B1) in which the acid anhydride group-containing conjugated diene polymer block [D(A2)] in the block copolymer (A2) is converted into a modifying group-containing conjugated diene polymer block [D(B1)] having a unit derived from a conjugated diene monomer into which an acyl group-containing group and a carboxyl group have been introduced;
The production method preferably includes a third step (hydrogenation step) in which the modified group-containing block copolymer (B1) is subjected to a hydrogenation treatment to hydrogenate at least a portion of the modified group-containing conjugated diene polymer block [D(B1)] in the modified group-containing block copolymer (B1) to obtain a modified group-containing hydrogenated conjugated diene polymer block [D(C1)].

As a method for producing the modified group-containing hydrogenated block copolymer of the present invention, a production method including a fourth step (ionization step) after the above-mentioned steps 1 to 3, in which the modified group-containing hydrogenated block copolymer (C1) is reacted with a base to convert at least a portion of the carboxyl groups into ionic groups consisting of a salt of a carboxylic acid, so that the modified group-containing hydrogenated conjugated diene polymer block [D(C1)] in the modified group-containing hydrogenated block copolymer (C1) becomes an ionic group-containing hydrogenated conjugated diene polymer block [D(C2)] having at least a portion of units derived from a conjugated diene monomer into which an ionic group consisting of an acyl group-containing group and a salt of a carboxylic acid has been introduced, to produce an ionic group-containing hydrogenated conjugated diene polymer block [D(C2)].

The above-mentioned preferred production method is described below, but the method for producing the modified group-containing hydrogenated block copolymer of the present invention is not limited to this production method.

The base polymer (A1) used in the first step can be produced according to a conventional method. Radical living polymerization, cationic living polymerization, ring-opening metathesis polymerization, etc. may be used, but the most common production method is anionic living polymerization, in which an aromatic vinyl monomer and a conjugated diene monomer are polymerized sequentially to form a polymer block, and if necessary, a coupling agent is reacted to perform coupling.

In addition, when the base polymer (A1) is a mixture of two or more types of block copolymers, the method for obtaining the mixture of block copolymers is not particularly limited, and the mixture can be produced according to a conventional method for producing block copolymers. For example, the mixture can be produced by separately producing two or more types of block copolymers, blending other polymer components and various additives as necessary, and then mixing them according to a conventional method such as kneading or solution mixing.

The method for obtaining a mixture of block copolymers may be, for example, a method in which aromatic vinyl-conjugated diene block copolymer a is obtained, and then an aromatic vinyl polymer block is bonded to the end of a portion of the aromatic vinyl-conjugated diene block copolymer a to obtain aromatic vinyl-conjugated diene-aromatic vinyl block copolymer b, i.e., a method for simultaneously preparing two types of block copolymers. For specific examples, see International Publication No. 2009/123089, JP 2012-77158 A, etc.

The resulting block copolymer mixture may be processed into pellets or the like in the usual manner before use.

In the first step, it is preferable to obtain a block copolymer (A2) in which an acid anhydride group is introduced into at least a portion of the conjugated diene polymer block [D(A1)] in the base polymer (A1) by reacting the base polymer (A1) with an unsaturated dicarboxylic acid anhydride as an acid modifier, resulting in an acid anhydride group-containing conjugated diene polymer block [D(A2)].

In other words, in the first step, it is preferable to perform acid modification of the base polymer (A1) with an unsaturated dicarboxylic acid anhydride to obtain the block copolymer (A2). The acid modification may be performed once or multiple times. When the acid modification is performed multiple times, the conditions for the acid modification may be the same or different for each time.

Unsaturated dicarboxylic acid anhydrides include those mentioned above. Unsaturated dicarboxylic acid anhydrides can be used alone or in combination of two or more.

The amount of unsaturated dicarboxylic acid anhydride used is usually 0.01 to 200 parts by mass, preferably 0.05 to 100 parts by mass, per 100 parts by mass of base polymer (A1).

The reaction temperature for the acid modification reaction can usually be in the range of 50 to 300°C. The reaction time can usually be in the range of 5 minutes to 20 hours. In addition, during the acid modification reaction, a solvent, a diluent, a gelling inhibitor, an antioxidant, a reaction accelerator, etc. may be present as necessary.

After the acid modification reaction, it is preferable to remove any unreacted unsaturated dicarboxylic acid anhydride. The removal method is not particularly limited, and examples include washing, neutralization, filtration, drying, etc.

In the second step, it is preferable to obtain a modified group-containing block copolymer (B1) in which the acid anhydride group-containing conjugated diene polymer block [D(A2)] in the block copolymer (A2) is converted into a modified group-containing conjugated diene polymer block [D(B1)] having at least a portion of units derived from a conjugated diene monomer into which an acyl group-containing group and a carboxyl group have been introduced, by reacting the block copolymer (A2) with an acyl-substituting compound.

In other words, in the second step, it is preferable to obtain a modifying group-containing block copolymer (B1) having a modifying group introduced therein by an acyl substitution reaction of the block copolymer (A2). The acyl substitution reaction may be carried out once or multiple times. When the acyl substitution reaction is carried out multiple times, the conditions for the acyl substitution reaction may be the same or different for each time.

　The acyl-substituting compounds used in the acyl substitution reaction can be those mentioned above. The bases can be used alone or in combination of two or more.

The amount of the acyl-substituting compound used can be equimolar or more relative to the acid anhydride groups introduced into the block copolymer (A2), and specifically can be about 1 to 100 times the molar amount.

The acyl substitution reaction is preferably carried out in a solvent in the presence of a catalyst. As the catalyst, triethylamine, trimethylamine, and tributylamine are preferred, and triethylamine is more preferred. In addition, as the solvent, for example, aliphatic halogenated hydrocarbons having 1 to 2 carbon atoms such as 1,2-dichloroethane, chloroform, dichloromethane, and 1,1-dichloroethane, aliphatic cyclic hydrocarbons such as cyclohexane, methylcyclohexane, and cyclopentane, nitromethane, nitrobenzene, acetonitrile, tetrahydrofuran, tetrahydropyran, 1,2-dimethoxyethane, acetone, methyl ethyl ketone, dimethyl sulfoxide, dimethylformamide, and pyrrolidone can be mentioned. The catalyst and the solvent can be used alone or in combination of two or more kinds.

The acyl substitution reaction conditions can be appropriately selected depending on the type of acyl substitution reaction. For example, the acyl substitution reaction temperature can be 0 to 200°C, and preferably 10 to 150°C. If the reaction temperature is too low, the reaction rate will be slow, and if it is too high, there is a risk of the block copolymer (A2) being thermally decomposed. The reaction time varies depending on the reaction temperature, but can be, for example, 1 minute to 40 hours, and preferably 3 minutes to 20 hours. If the reaction time is too short, the reaction will not proceed sufficiently, and if it is too long, there is a risk of poor reaction efficiency.

The reaction rate of the acyl substitution reaction is not particularly limited, but is preferably 1 mol% to 95 mol%, more preferably 10 mol% to 90 mol%, and even more preferably 30 mol% to 80 mol%, in terms of the ratio of [number of acyl group-containing groups formed by the acyl substitution reaction/number of acid anhydride groups introduced into the block copolymer (A2)]. For example, when an alcohol is used as the acyl-substituting compound, the above ratio is expressed as [ester bond-containing groups formed by the acyl substitution reaction/number of acid anhydride groups introduced into the block copolymer (A2)].

After the acyl substitution reaction, it is preferable to remove the remaining acyl-substituting compound and catalyst. There are no particular limitations on the method of removal, and examples of the method include washing, neutralization, filtration, drying, etc.

In the third step, it is preferable to hydrogenate the modified group-containing block copolymer (B1) to obtain a modified group-containing hydrogenated block copolymer (C1) in which at least a portion of the modified group-containing conjugated diene polymer block [D(B1)] in the modified group-containing block copolymer (B1) is hydrogenated to form a modified group-containing hydrogenated conjugated diene polymer block [D(C1)].

In other words, in the third step, it is preferable to obtain the modified group-containing hydrogenated block copolymer (C1) by hydrogenating the modified group-containing block copolymer (B1). The hydrogenation may be carried out once or multiple times. When the hydrogenation is carried out multiple times, the hydrogenation conditions may be the same or different for each time.

The hydrogenation treatment is preferably carried out, for example, by reacting the modifying group-containing block copolymer (B1) with p-toluenesulfonyl hydrazide in a solvent. Examples of the solvent include aliphatic halogenated hydrocarbons having 1 to 2 carbon atoms, such as 1,2-dichloroethane, chloroform, dichloromethane, and 1,1-dichloroethane; aliphatic cyclic hydrocarbons, such as cyclohexane, methylcyclohexane, and cyclopentane; xylene, tromethane, nitrobenzene, acetonitrile, tetrahydrofuran, tetrahydropyran, 1,2-dimethoxyethane, acetone, methyl ethyl ketone, dimethyl sulfoxide, dimethylformamide, and pyrrolidone. The solvents may be used alone or in combination of two or more.

The amount of p-toluenesulfonyl hydrazide used may be 100 to 2,000 parts by weight per 100 parts by weight of the modifying group-containing block copolymer (B1).

The hydrogenation treatment conditions can be appropriately selected depending on the desired hydrogenation rate, etc. For example, the reaction temperature can be 110 to 160°C, and preferably 120 to 150°C. The reaction time varies depending on the reaction temperature, but can be, for example, 10 minutes to 20 hours, and preferably 15 minutes to 10 hours. If the reaction time is too short, the reaction will not proceed sufficiently, and if it is too long, the reaction efficiency may be poor.

After the hydrogenation process, it is preferable to remove any remaining p-toluenesulfonyl hydrazide solvent, etc. The removal method is not particularly limited, and examples include washing, neutralization, filtration, drying, etc.

By the manufacturing method including the above-mentioned steps 1 to 3, a modified group-containing hydrogenated block copolymer (C1) having an acyl group-containing group and a carboxyl group as a modified group can be obtained. The modified group-containing hydrogenated block copolymer of the present invention may be the carboxyl group-containing hydrogenated block copolymer (C1) obtained in this manner.

In addition, the method for producing the modified group-containing hydrogenated block copolymer of the present invention preferably includes a fourth step, which is carried out after the above-mentioned first to third steps, in which the modified group-containing hydrogenated block copolymer (C1) is reacted with a base to convert at least a portion of the carboxyl groups in the modified group-containing hydrogenated block copolymer (C1) into ionic groups consisting of a salt of a carboxylic acid, thereby converting the modified group-containing hydrogenated conjugated diene polymer block [D(C1)] in the modified group-containing hydrogenated block copolymer (C1) into an ionic group-containing hydrogenated conjugated diene polymer block [D(C2)] having at least a portion of units derived from a conjugated diene monomer into which an acyl group-containing group and an ionic group consisting of a salt of a carboxylic acid have been introduced.

In the fourth step, the modified group-containing hydrogenated block copolymer (C1) is treated with a base to obtain an ionic group-containing hydrogenated block copolymer (C2). The base treatment may be carried out once or multiple times. When the base treatment is carried out multiple times, the conditions for the base treatment may be the same or different for each time.

The base may be any of those mentioned above. The base may be used alone or in combination of two or more.

The amount of base used is appropriately selected depending on the desired introduction rate of ionic groups, etc. For example, the amount of base used can be equimolar or more relative to the carboxyl groups in the carboxyl group-containing hydrogenated block copolymer (C1), and specifically can be about 1 to 2 times the molar amount. The amount of base used can also be about 1 to 2 times the molar amount relative to the acid anhydride groups introduced in the first step.

The base treatment may be carried out without a solvent or in a solvent. When the base treatment is carried out in a solvent, examples of the solvent include aliphatic halogenated hydrocarbons having 1 to 2 carbon atoms, such as 1,2-dichloroethane, chloroform, dichloromethane, and 1,1-dichloroethane; aliphatic cyclic hydrocarbons, such as cyclohexane, methylcyclohexane, and cyclopentane; methanol, nitromethane, nitrobenzene, acetonitrile, tetrahydrofuran, tetrahydropyran, 1,2-dimethoxyethane, acetone, methyl ethyl ketone, dimethyl sulfoxide, dimethylformamide, pyrrolidone, and water. The solvent may be used alone or in a mixture of two or more.

The reaction temperature for the base treatment varies depending on the type of carboxyl group introduced into the carboxyl group-containing hydrogenated block copolymer (C1) and the type of base, but can be, for example, 0 to 200°C, and preferably 10 to 150°C. If the reaction temperature is too low, the reaction rate will be slow, and if it is too high, there is a risk of the carboxyl group-containing hydrogenated block copolymer (C1) being thermally decomposed. The reaction time varies depending on the reaction temperature, but can be, for example, 1 minute to 40 hours, and preferably 3 minutes to 2 hours. If the reaction time is too short, the reaction will not proceed sufficiently, and if it is too long, there is a risk of poor reaction efficiency.

After the base treatment, it is preferable to remove any remaining base. The removal method is appropriately selected depending on the base treatment and the type of base, and examples include washing, neutralization, filtration, drying, etc.

By the manufacturing method including the above-mentioned steps 1 to 4, an ionic group-containing hydrogenated block copolymer (C2) having an ionic group consisting of a salt of a carboxylic acid is obtained. The modified group-containing hydrogenated block copolymer of the present invention is preferably the ionic group-containing hydrogenated block copolymer (C2) obtained in this manner.

In addition to the above-mentioned methods, the hydrogenated block copolymer containing a modifying group of the present invention can also be produced by hydrogenating the base polymer (A1) to obtain a hydrogenated block copolymer in which the conjugated diene polymer block [D(A1)] in the base polymer (A1) is converted into a hydrogenated conjugated diene polymer block, and then performing a modification treatment to introduce a non-covalently bondable modifying group on the hydrogenated block copolymer. In such a production method, the introduction rate of the non-covalently bondable modifying group tends to be low (for example, less than 1 mol % in 100 mol % of units derived from the conjugated diene monomer).

In contrast, according to the manufacturing method including the above-mentioned steps 1 to 3, it is easy to increase the introduction rate of the non-covalently bondable modifying group (for example, 1 mol % or more out of 100 mol % of units derived from the conjugated diene monomer), and this makes it possible to appropriately increase the effect of introducing the modifying group.

The modified group-containing hydrogenated block copolymer of the present invention can be used as a material for various components in various technical fields such as the medical field, adhesive field, electronic field, and optical field. For example, it can be suitably used for molding material applications such as films, gloves, elastic bands, contraceptives, OA equipment, various rolls for office use, vibration-proof sheets for electrical and electronic equipment, vibration-proof rubber, shock-absorbing sheets, shock-buffering films and sheets, vibration-proof sheets for housing, vibration-proof damper materials, etc., adhesive applications such as adhesive tapes, adhesive sheets, adhesive labels, and dust rollers, adhesive applications for sanitary products and bookbinding, and elastic fiber applications for clothing and sporting goods. In particular, the modified group-containing hydrogenated block copolymer of the present invention has high tensile strength and suitable tensile properties, and has a high retention rate of tensile properties (particularly the retention rate of tensile strength and breaking energy) under ultraviolet irradiation. Therefore, the modified group-containing hydrogenated block copolymer of the present invention can be suitably used as a material for various components that require these properties.

The present invention will be explained in more detail below with examples and comparative examples.

[Example 1]
In Example 1, Quintac (registered trademark) 3440 (manufactured by Zeon Corporation, polystyrene-polyisoprene block copolymer) was used as the block copolymer serving as the base polymer, and an addition reaction with maleic anhydride was carried out according to the reaction formula shown below to introduce a succinic anhydride unit (introduction rate 4.4 mol%) (step 1), and then an acyl substitution reaction between 1-butanol and the succinic anhydride unit was carried out to synthesize a block copolymer having an ester having a nonionic and neutral organic substituent and a carboxy group (step 2). Subsequently, a hydrogenation reaction was carried out on this block copolymer to convert 99.6% of the C=C double bonds in the polyisoprene block to single bonds (step 3). Furthermore, the carboxy group was neutralized with sodium methoxide to form a carboxylate anion group having a sodium cation as a counter cation, and a hydrogenated block copolymer having an ionic group that combines high strength and high weather resistance was prepared (step 4). Quintac3440 is a polystyrene-polyisoprene block copolymer whose main component is polystyrene-b-polyisoprene-b-polystyrene triblock copolymer. The content of styrene units in all monomer units of Quintac3440, as determined by the refractive index method, is 18% by mass. A chart based on the molecular weight converted to polystyrene was obtained by high performance liquid chromatography using tetrahydrofuran as a carrier at a flow rate of 0.35 ml/min, and the weight average molecular weight of Quintac3440 determined based on the obtained chart was 210,000. The apparatus used was Tosoh Corporation's HLC8320, the column was Showa Denko KK's Shodex (registered trademark) KF-404HQ, three columns were connected (column temperature 40°C), and the detector was a differential refractometer and an ultraviolet detector, and the molecular weight was calibrated at 12 points of standard polystyrene (5 to 3 million) manufactured by Polymer Laboratory Co., Ltd. The melt index (G condition, 200°C, 5 kg) was 9.0 g/10 min. In addition, in the following scheme 1, as the structure of the product in the second step, a structure in which a carboxy group is directly bonded to a carbon atom bonded to the main chain, and a butyl ester group is bonded to a carbon atom bonded to the main chain via a methyl group is exemplified. On the other hand, as the structure of the product in the second step, a structure in which a butyl ester group is directly bonded to a carbon atom bonded to the main chain, and a carboxy group is bonded to a carbon atom bonded to the main chain via a methyl group may be included. (The same applies to the structures of the products in the third and fourth steps.)

Table 1 summarizes the functional group introduction rate and reaction rate in each process. The specific steps are shown below.

[1-1] Step 1 (modification with maleic anhydride)
A block copolymer (Quintac3440) as a base polymer, an antioxidant N-(1,3-dimethylbutyl)-N'-phenyl-1,4-phenylenediamine (hereinafter referred to as 6PPD), and a solvent cyclohexane were weighed out in amounts of 248 g, 0.41 g, and 675 g, respectively, and mixed at 60°C using a mechanical stirrer to prepare a solution. 62 g of maleic anhydride was added to the resulting solution, and the inside of the reaction vessel was replaced with nitrogen, and the reaction was carried out by stirring at 0.88 MPa and a temperature of 160°C or higher for about 1.5 hours. The reaction was then terminated by cooling the reaction vessel in an ice bath.

About 30 g of the above solution was added to 300 mL of toluene, and this solution was dropped into 3,000 mL of acetonitrile to precipitate a block copolymer with succinic anhydride units. The resulting polymer was separated by suction filtration and thoroughly dried by vacuum drying, then dissolved again in toluene and dropped into acetonitrile to precipitate the polymer. The resulting polymer was separated by suction filtration and thoroughly dried by vacuum drying. This operation was repeated twice to remove unreacted maleic anhydride and the cyclohexane solvent.

The purified block copolymer into which the succinic anhydride unit had been introduced was dissolved in deuterated chloroform to prepare a solution of about 2% by mass, and the introduction rate of the succinic anhydride unit relative to the polyisoprene block in the block copolymer was determined by proton nuclear magnetic resonance spectroscopy ( ¹ H-NMR) measurement. The ¹ H-NMR spectra of the block copolymer before and after the introduction of the succinic anhydride unit are shown at the top and second from the top in FIG. 1. New peaks were observed at 2.3 to 3.5 ppm, which were attributable to three protons (r and s) on the succinic anhydride unit and one proton (p) attached to the carbon next to the succinic anhydride unit. From the integral ratio of the peak at 4.5 to 4.9 ppm attributable to two protons (l and o) of the vinylidene group and the peak at 4.9 to 5.3 ppm attributable to one proton (h) attached to the carbon with a double bond in poly(1,4-isoprene), the introduction rate of the succinic anhydride unit relative to the polyisoprene block was estimated to be 4.4 mol%.

In addition, the block copolymer into which the succinic anhydride unit had been introduced was dissolved in tetrahydrofuran (hereinafter referred to as THF) to prepare a solution of about 0.1% by mass, and gel permeation chromatography (GPC) measurement was performed. The eluent was THF, the flow rate was 1 mL/min, and the measurement was performed in a state in which two TSKgel columns GMH _HR -M manufactured by Tosoh Corporation were connected. In FIG. 2, the dashed line shows Quintac 3440, and the solid line shows the GPC chromatogram after the succinic anhydride unit introduction reaction. Since no significant change was observed in the peak shape before and after the reaction, it was confirmed that almost no cleavage of the conjugated diene portion or crosslinking between polymers occurred.

In addition, the polymer was dissolved in THF to prepare a solution of about 8% by mass, and 5 drops of the solution were dropped onto a potassium bromide plate using a Pasteur pipette, and the solution was left to stand at room temperature for 3 hours or more to evaporate the THF. The solvent was then completely removed by drying at 40°C for 3 hours or more using a vacuum dryer, and the obtained film was subjected to transmission Fourier transform infrared absorption spectroscopy (FT-IR) measurement. The measurement device used was an infrared spectrophotometer FT/IR-6100 manufactured by JASCO. The IR spectra of Quintac3440 and the block copolymer after the succinic anhydride unit introduction reaction are shown at the top and second from the top in Figure 3, respectively. In the case of Quintac3440 before the reaction of introducing the succinic anhydride unit, no absorption was observed at 1700 to 1900 cm ^-1 , but in the case of the block copolymer after the reaction of introducing the succinic anhydride unit, absorption due to the stretching vibration of the carbonyl group of the acid anhydride was observed at 1788 and 1864 cm ^- 1, confirming that the succinic anhydride unit had been introduced. The absorption near 1600 cm ^-1 is due to the C=C stretching vibration of the phenyl group of polystyrene.

[1-2] Step 2 (acyl substitution reaction with alcohol)
In a nitrogen-substituted flask, 22.0 g of the succinic anhydride unit-introduced block copolymer obtained in the first step was dissolved in 79.9 g of THF previously dehydrated with a molecular sieve, and 24.3 g of 1-butanol and 2.18 g of triethylamine were further added. At this time, the amounts of 1-butanol and triethylamine relative to the acid anhydride unit were about 28 equivalents and about 1.9 equivalents, respectively. The flask was placed in an oil bath at 50°C and stirred for about 15 hours. The solution after the reaction was dropped into 2000 mL of methanol to precipitate a block copolymer in which 1-butanol and succinic anhydride units were subjected to an acyl substitution reaction. The obtained polymer was separated by suction filtration and thoroughly dried by vacuum drying, and then dissolved in THF and dropped again into methanol to precipitate the polymer. The obtained polymer was separated by suction filtration and thoroughly dried by vacuum drying. This purification operation was repeated twice to remove unreacted 1-butanol and triethylamine used as a catalyst.

The obtained block copolymer after the acyl substitution reaction was dissolved in deuterated chloroform to prepare a solution of about 2% by mass, and ¹ H-NMR measurement was performed. The obtained ¹ H-NMR is shown in the third from the top in FIG. 1. Since a peak intensity derived from the proton (z) of the methylene group adjacent to the oxygen atom of the ester was observed around 4.1 ppm, it was confirmed that the succinic anhydride unit reacted with 1-butanol to obtain a block copolymer having an ester having a nonionic and neutral organic substituent. From the integral ratio of the peak at 4.5 to 4.9 ppm derived from the two protons (l and u) of the vinylidene group and the peak at 4.9 to 5.3 ppm derived from one proton (h) attached to the carbon having a double bond in poly(1,4-isoprene), 1-butanol reacted with 67.8 mol% of the succinic anhydride unit. The introduction rate of the ester bond-containing group introduced by the acyl substitution reaction was 3.0 mol% with respect to the total number of monomer units of the isoprene polymer block in the base polymer. In addition, FT-IR measurement was performed in the same manner as before the acyl substitution reaction (third from the top in Figure 3), and a broad absorption at 3100 to 3500 cm ^-1 due to the O-H stretching vibration of the carboxy group, an absorption at 1710 cm ^-1 due to the C=O stretching vibration of the carboxy group, and an absorption at 1738 cm ^-1 due to the C=O stretching vibration of the ester bond were newly observed, confirming that the succinic anhydride unit reacted with 1-butanol to obtain a block copolymer having an ester having a nonionic neutral organic substituent and a carboxy group. On the other hand, the absorption at 1788 and 1864 cm ^-1 due to the stretching vibration of the carbonyl group of the acid anhydride almost disappeared, indicating that almost all of the succinic anhydride units had reacted, and that the succinic anhydride units that did not react with 1-butanol had undergone an acyl substitution reaction with water present in the reaction system and were converted to two carboxy groups.

[1-3] Third step (hydrogenation reaction)
In order to convert the C=C double bond of the obtained block copolymer having an ester with a nonionic and neutral organic substituent and a carboxy group into a single bond, a hydrogenation reaction was carried out in the third step. 10.0 g of the block copolymer having an ester with a nonionic and neutral organic substituent and a carboxy group was dissolved in 153 g of p-xylene, and then 101 g of p-toluenesulfonyl hydrazide was added. A Dimroth condenser was attached to the flask, and the mixture was stirred in an oil bath at 130°C for 4.5 hours. The solution after the reaction was dropped into 1500 mL of methanol to precipitate the block copolymer after the hydrogenation reaction. The obtained polymer was separated by suction filtration, thoroughly dried by vacuum drying, dissolved in THF, and dropped again into methanol to precipitate the polymer. The obtained polymer was separated by suction filtration and thoroughly dried by vacuum drying. This purification operation was repeated twice to remove unreacted p-toluenesulfonyl hydrazide, its by-products, solvent, etc. The hydrogenation reaction was further repeated several times on the obtained product.

The hydrogenated block copolymer thus obtained was dissolved in deuterated chloroform to prepare a solution of about 2% by mass. ¹ H-NMR measurement was performed (bottom of FIG. 1). The peak at 4.5 to 5.3 ppm derived from the protons attached to the C=C double bonds was considerably small, and it was found that 99.6% of the C=C double bonds were converted to single bonds based on the integral ratio with the peak at 6.2 to 7.2 ppm derived from the phenyl group of polystyrene. On the other hand, the peak intensity derived from the protons of the methylene group adjacent to the oxygen atom of the ester was observed at about 4.1 ppm, confirming that the ester had hardly reacted. In addition, FT-IR measurement was performed in the same manner as the sample before the hydrogenation reaction (second from the bottom of FIG. 3). It was confirmed that the absorption at 1644 and 1664 cm ⁻¹ derived from the stretching vibration of the C=C double bonds observed before the hydrogenation reaction had almost disappeared, confirming that the C=C double bonds had almost disappeared. Furthermore, the broad absorption at 3100 to 3500 cm ⁻¹ due to the O-H stretching vibration of the carboxy group, the absorption at 1710 cm ⁻¹ due to the C═O stretching vibration of the carboxy group, and the absorption at 1738 cm ⁻¹ due to the C═O stretching vibration of the ester bond showed almost no change before and after the hydrogenation reaction, confirming that the ester having a nonionic, neutral organic substituent and the carboxy group showed almost no change.

[1-4] Step 4 (Introduction of ionic functional groups by neutralization of carboxy groups)
The carboxyl group of the block copolymer after the hydrogenation reaction is acidic, and it is believed that the addition of a basic compound will form a salt or an acid-base complex, resulting in ionic interaction. 4.03 g of the modified block copolymer after the hydrogenation reaction was dissolved in 40 g of a mixed solvent of THF/methanol = 9/1 (weight ratio), and 388 μL of a methanol solution of sodium methoxide (concentration 5 mol/L) was added using a micropipette (maximum capacity 100 μL). At this time, the amount of sodium methoxide was almost equimolar to the succinic anhydride unit before modification with 1-butanol. 0.0042 g of Irgafos168 and 0.0035 g of Irganox565 were added as antioxidants, and the mixture was stirred at room temperature for about 1 hour. Thereafter, the solution was transferred to a container made of polyperfluoroalkoxyalkane (hereinafter referred to as PFA) and left to stand at 40 ° C. for 2 days to evaporate the solvent. Then, the solvent was completely removed by drying at 40 ° C. for about 2 days using a vacuum dryer. The resulting sample of hydrogenated block copolymer having ionic groups was in the form of a film.

When FT-IR measurement was performed in the same manner as for the sample before ionization (bottom of FIG. 3), changes were observed in the broad absorption at 3100 to 3500 cm ⁻¹ due to the O-H stretching vibration of the carboxy group and the absorption at 1710 cm ⁻¹ due to the C═O stretching vibration of the carboxy group, and a new absorption near 1570 cm ⁻¹ due to the C-O stretching vibration of the carboxylate anion was observed, confirming that the carboxy group had reacted with sodium methoxide and been converted to a carboxylate anion group having a sodium cation as a counter cation. The content of non-covalently bondable functional groups in the obtained hydrogenated block copolymer having ionic groups can be estimated to be 4.4 mol %×2−3.0 mol %=5.8 mol %, since the introduction rate of the succinic anhydride unit is 4.4 mol % and the introduction rate of the ester bond-containing group introduced by the acyl substitution reaction is 3.0 mol %. The content of ionic groups (carboxylate anion groups) was 4.4 mol%, the content of functional groups capable of hydrogen bonding (carboxy groups) was 1.4 mol%, and the content of styrene units in all monomer units of the obtained hydrogenated block copolymer having ionic groups was 17 mass%.

[2-1] Tensile Test In order to evaluate simple tensile properties, a uniaxial tensile test was performed. Specifically, the obtained membrane sample of the hydrogenated block copolymer having an ionic group in the form of a membrane was punched with a punching blade corresponding to the dumbbell-shaped No. 7 type (corresponding to Type 4 in the International Organization for Standardization ISO37:2017) described in the Japanese Industrial Standards JIS K6251:2017 to prepare a test piece. The thickness of the test piece was about 0.6 mm. The measurement device was Shimadzu AGS-X, a 50N load cell, and a pneumatic flat-type gripper, and the tensile test was performed at an air pressure of 0.40 MPa, room temperature, a gripper distance of about 10 mm, and an initial strain rate of 0.10/s (tensile rate of about 1.0 mm/s). The stress-strain curve resulting from the tensile test is shown by a dashed line in FIG. 4. The Young's modulus, tensile strength, breaking elongation, and toughness (the inner area value of the stress-strain curve, which corresponds to the breaking energy) were 8.7 MPa, 18.6 MPa, 1330%, and 103 MJ/ ^m3 , respectively (Table 2). The Young's modulus was determined from the initial gradient of the stress-strain curve (the gradient at strains of 0 to 15%), the tensile strength from the maximum stress, and the breaking elongation from the elongation at which breaking occurred.

[2-2] Weather resistance evaluation In order to evaluate the weather resistance of the obtained hydrogenated block copolymer film sample having ionic groups, an accelerated weather resistance tester was used to accelerate the deterioration of the film, and then a tensile test was performed. A xenon weather meter (manufactured by Suga Test Instruments, SC700-WAP) was used as the accelerated weather resistance tester, and light with a wavelength distribution similar to that of sunlight was irradiated for 24 hours or 48 hours under the conditions of a black panel temperature of 63°C, a relative humidity of 50% RH, and an irradiance of 60 W/ ^m2 . Thereafter, the tensile properties were evaluated in the same manner as in 2-1, and the Young's modulus, tensile strength, breaking elongation, and toughness of the film irradiated with light for 24 hours were 7.4 MPa, 19.1 MPa, 1470%, and 112 MJ/ ^m3 , respectively (solid line in Figure 4, Table 2), and the ratio (retention rate) of each tensile property after use of the accelerated weather resistance tester to that before use was 85%, 103%, 111%, and 109%, respectively, and almost no deterioration was observed. The Young's modulus, tensile strength, breaking elongation, and toughness of the film irradiated with light for 48 hours were 7.7 MPa, 16.3 MPa, 1360%, and 99 MJ/ ^m3 , respectively (chain line in FIG. 4, Table 2). The ratios (retention rates) of each tensile property after use in the accelerated weathering tester to those before use were 89%, 88%, 102%, and 96%, respectively, and almost no deterioration was observed.

[Comparative Example 1]
In Comparative Example 1, a block copolymer (Quintac 3440), which was the base polymer of Example 1, was subjected to a hydrogenation reaction in the same manner as in the third step of Example 1 to convert 99.1% of the double bonds in the main chain to single bonds, thereby preparing a hydrogenated block copolymer.

A hydrogenation reaction was carried out in the same manner as in the third step of Example 1, except that Quintac 3440 was used as the polymer. When ¹ H-NMR measurement was carried out in the same manner as in Example 1 ( FIG. 5 ), it was found that the peaks at 4.5 to 5.3 ppm derived from the protons attached to the C═C double bonds had almost disappeared, and it was found that 99.1% of the C═C double bonds had been converted to single bonds based on the integral ratio with the peaks at 6.2 to 7.2 ppm derived from the phenyl groups of polystyrene. In addition, when FT-IR measurement was carried out in the same manner as for the sample before hydrogenation ( FIG. 6 ), it was confirmed that the C═C double bonds had almost disappeared, since the absorptions at 1644 and 1664 cm ⁻¹ derived from the stretching vibrations of the C═C double bonds seen before the hydrogenation reaction had almost disappeared.

GPC measurements were also performed in the same manner as in Example 2. In Figure 7, the dotted line shows the GPC chromatogram for Quintac 3440, and the solid line shows the GPC chromatogram after the hydrogenation reaction. Since no significant change was observed in the peak shape before and after the reaction, it was confirmed that the hydrogenation reaction caused almost no scission of the main chain or crosslinking between polymers.

In order to evaluate simple tensile properties, a membrane sample was prepared by the solution casting method as in Example 1, and a uniaxial tensile test was performed, and the results shown by the dotted line in Figure 4 were obtained. The Young's modulus, tensile strength, breaking elongation, and toughness were 7.3 MPa, 9.0 MPa, 1460%, and 65 MJ/ ^m3 , respectively (Table 2). The breaking elongation of the sample of Example 1 was almost the same as that of the sample of Comparative Example 2, but it showed higher tensile strength and therefore higher toughness. The reason why the tensile strength of Example 1 was high is thought to be because micro-ion aggregation occurred due to the introduced carboxylate anion group and sodium cation, and this micro-ion aggregation increased the apparent crosslinking point density. In addition, in Example 1, stress concentration on the polystyrene isolated domain was also avoided due to the cleavage and recombination of the micro-ion aggregation, which suppressed the pulling out of polystyrene chains from the domain and suppressed early breakage, and therefore it is thought that the elongation was about the same as that of Comparative Example 1.

[Comparative Example 2]
In Comparative Example 2, the base polymer of Example 1, that is, the block copolymer (Quintac 3440) itself (containing no additives such as talc) that had not been subjected to a hydrogenation reaction was used.

In order to evaluate simple tensile properties, a membrane sample was prepared by the solution casting method as in Example 1, and a uniaxial tensile test was performed. The results shown by the dashed lines in FIG. 8 were obtained. The Young's modulus, tensile strength, breaking elongation, and toughness of the membrane of Comparative Example 2 were 2.4 MPa, 9.4 MPa, 2940%, and 114 MJ/m ³ , respectively, which were almost the same values as the data measured at a gripper distance of about 10 mm and an initial strain rate of 0.10/s (tensile rate of about 1.0 mm/s) as shown in FIG. 1a and Table 1 of the non-patent document ACS Omega 2022, 7, 2821-2830.

Weather resistance evaluation In order to evaluate the weather resistance of the film sample of Comparative Example 2, the deterioration of the film was accelerated for 24 hours or 48 hours using an accelerated weather resistance tester in the same manner as in 2-2 of Example 1, and then a tensile test was performed. The Young's modulus, tensile strength, breaking elongation, and toughness of the film irradiated with light for 24 hours were 1.3 MPa, 1.4 MPa, 1040%, and 9.7 MJ/ ^m3 , respectively (solid line in FIG. 8, Table 2). The ratio (retention rate) of each tensile property after using the accelerated weather resistance tester to that before using the tester was 54%, 15%, 35%, and 8.5%, respectively, and the retention rate of each tensile property was small. The Young's modulus, tensile strength, elongation at break, and toughness of the film irradiated with light for 48 hours were 1.2 MPa, 1.0 MPa, 790%, and 5.8 MJ/ ^m3 , respectively (chain line in FIG. 8, Table 2), and the ratio (retention) of each tensile property after use of the accelerated weathering tester to that before use was 50%, 11%, 27%, and 5.1%, respectively, and the retention of each tensile property was small. These values were very small compared to the retention of tensile strength and toughness in Example 1, and the sample in Example 1 showed higher weather resistance. It is believed that the low weather resistance of the sample in Comparative Example 2 was due to the double bond in the main chain being decomposed by ultraviolet light. On the other hand, it is believed that the sample in Example 1 showed a high retention rate because there were almost no double bonds in the main chain due to the hydrogenation reaction, and there was almost no reaction due to ultraviolet light, and it was difficult to deteriorate.

[Comparative Example 3]
In Comparative Example 3, a high-strength block copolymer having an ionic group was prepared by carrying out the fourth step without carrying out the hydrogenation reaction in the third step on the block copolymer having an ester having a nonionic and neutral organic substituent and a carboxyl group obtained in the second step of Example 1. The content of the ionic group in the ionic group-containing block copolymer obtained in Comparative Example 3 was 4.4 mol%, and the membrane sample was prepared in the same manner as in the fourth step of Example 1.

In order to evaluate simple tensile properties, a uniaxial tensile test was carried out in the same manner as in Example 1. The results shown by the dashed line in FIG. 9 were obtained, with the Young's modulus, tensile strength, elongation at break, and toughness being 4.0 MPa, 31.2 MPa, 2890%, and 303 MJ/ ^m3 , respectively.

Weather resistance evaluation In order to evaluate the weather resistance of the film sample of Comparative Example 3, the deterioration of the film was accelerated for 24 hours or 48 hours using an accelerated weather resistance tester in the same manner as in 2-2 of Example 1, and then a tensile test was performed. The Young's modulus, tensile strength, breaking elongation, and toughness of the film irradiated with light for 24 hours were 2.0 MPa, 8.9 MPa, 2540%, and 102 MJ/ ^m3 , respectively (solid line in FIG. 9, Table 2). The ratios (retention rates) of each tensile property after use of the accelerated weather resistance tester to those before use were 50%, 29%, 88%, and 34%, respectively, and the retention rate of tensile strength was low, and the retention rate of toughness was also low accordingly. The Young's modulus, tensile strength, elongation at break, and toughness of the film irradiated with light for 48 hours were 2.8 MPa, 8.6 MPa, 2530%, and 113 MJ/ ^m3 , respectively (chain line in FIG. 9, Table 2), and the ratios (retention rates) of each tensile property after use of the accelerated weathering tester to those before use were 70%, 28%, 88%, and 37%, respectively, and the retention rate of tensile strength was low, and the retention rate of toughness was also low accordingly. These values were smaller than the retention rates of tensile strength and toughness of Example 1, and the sample of Example 1 showed higher weather resistance. It is believed that the low weather resistance of the sample of Comparative Example 3 was due to the double bonds in the main chain being decomposed by ultraviolet light. On the other hand, it is believed that the sample of Example 1 showed a high retention rate because there were almost no double bonds in the main chain due to the hydrogenation reaction, and there was almost no reaction due to ultraviolet light, making it difficult to deteriorate.

[Example 2]
In Example 2, a film sample (hydrogenation rate of 99.6%) of a block copolymer obtained by hydrogenating an ester having a nonionic neutral organic substituent (butyl group) obtained in the third step of Example 1 and a carboxyl group was prepared, and its mechanical properties were evaluated. The introduction rate of the succinic anhydride unit was 4.4 mol%, and the introduction rate of the ester bond-containing group introduced by the acyl substitution reaction was 3.0 mol%, so the content of the non-covalently bondable functional group can be estimated as 4.4 mol% x 2-3.0 mol% = 5.8 mol%, of which the content of the ionic group (carboxylate anion group) was 0 mol%, and the content of the hydrogen-bondable functional group (carboxyl group) was 5.8 mol%.

In order to evaluate simple tensile properties, a uniaxial tensile test was performed in the same manner as in Example 1. The results shown by the dashed line in FIG. 10 were obtained, with the Young's modulus, tensile strength, elongation at break, and toughness being 3.9 MPa, 12.2 MPa, 1630%, and 83 MJ/ ^m3 , respectively.

Weather resistance evaluation In order to evaluate the weather resistance of the film sample of Example 2, the deterioration of the film was accelerated for 24 hours or 48 hours using an accelerated weather resistance tester in the same manner as in 2-2 of Example 1, and then a tensile test was performed. The Young's modulus, tensile strength, breaking elongation, and toughness of the film irradiated with light for 24 hours were 5.0 MPa, 10.0 MPa, 1350%, and 65 MJ/ ^m3 , respectively (solid line in FIG. 10, Table 2), and the ratio (retention rate) of each tensile property after using the accelerated weather resistance tester to that before using the tester was 128%, 82%, 83%, and 78%, respectively. The Young's modulus, tensile strength, elongation at break, and toughness of the film irradiated with light for 48 hours were 5.5 MPa, 9.0 MPa, 900%, and 42 MJ/ ^m3 , respectively (chain line in FIG. 10, Table 2), and the ratios (retention rates) of each tensile property after use of the accelerated weathering tester to those before use of the tester were 141%, 74%, 55%, and 51%, respectively. These values were larger than the retention rates of tensile strength, elongation at break, and toughness of Comparative Example 2, and the sample of Example 2 showed higher weather resistance. It is believed that the reason why the weather resistance of the sample of Comparative Example 2 was low is because the double bonds in the main chain were decomposed by ultraviolet light. On the other hand, it is believed that the sample of Example 2 showed a moderate retention rate because there were almost no double bonds in the main chain due to the hydrogenation reaction, and it was difficult to react with ultraviolet light and was difficult to deteriorate.

[Example 3]
In Example 3, a hydrogenated block copolymer membrane sample having 4.5 mol % of ionic groups (hydrogenation rate of 98.7%) was prepared and its mechanical properties were evaluated in the same manner as in Example 1, except that n-butylamine was reacted with the succinic anhydride unit in an equimolar amount instead of 1-butanol in the second step of Example 1. The introduction rate of the succinic anhydride unit was 4.5 mol %, and the introduction rate of the amide group introduced by the acyl substitution reaction was 2.0 mol %, so the content of non-covalently bondable functional groups can be estimated as 4.5 mol % x 2 = 9.0 mol %, of which the content of ionic groups (carboxylate anion groups) in the 9.0 mol % was 4.5 mol %, and the contents of hydrogen-bondable functional groups (carboxy groups and amide groups) were 2.5 mol % and 2.0 mol %, respectively.

In order to evaluate simple tensile properties, a uniaxial tensile test was carried out in the same manner as in Example 1, and the results shown by the dashed line in Fig. 11 were obtained, with the Young's modulus, tensile strength, breaking elongation, and toughness being 9.2 MPa, 27.6 MPa, 1290%, and 153 MJ/ ^m3 , respectively, and the sample of Example 3 exhibited higher Young's modulus and tensile strength, and also had greater toughness, compared to the sample of Comparative Example 2. This is believed to be due to the fact that micro-ionic aggregation occurred due to the introduced carboxylate anions and sodium cations, and this micro-ionic aggregation increased the apparent crosslinking point density.

[Example 4]
In Example 4, a membrane sample of a hydrogenated block copolymer having an ionic group was prepared in the same manner as in Example 1, except that 4-methoxyphenethyl alcohol was used instead of 1-butanol in the second step of Example 1. The introduction rate of succinic anhydride units was 1.7 mol%, and the introduction rate of ester bond-containing groups introduced by acyl substitution reaction was 0.6 mol%. Therefore, the content of non-covalently bondable functional groups can be estimated as 1.7 mol% x 2 - 0.6 mol% = 2.8 mol%, of which the content of ionic groups (carboxylate anion groups) was 1.7 mol%, and the content of hydrogen-bondable functional groups (carboxy groups) was 1.1 mol%.

[Example 5]
In Example 5, a membrane sample of a hydrogenated block copolymer having an ionic group was prepared in the same manner as in Example 1, except that 3-methyl-1-butanol was used instead of 1-butanol in the second step of Example 1. The introduction rate of succinic anhydride units was 1.7 mol%, and the introduction rate of ester bond-containing groups introduced by acyl substitution reaction was 0.9 mol%. Therefore, the content of non-covalently bondable functional groups can be estimated as 1.7 mol% x 2 - 0.9 mol% = 2.5 mol%, and the content of ionic groups (carboxylate anion groups) in the 2.5 mol% was 1.7 mol%, and the content of hydrogen-bondable functional groups (carboxy groups) was 0.8 mol%.

[Example 6]
In Example 6, a membrane sample of a hydrogenated block copolymer having an ionic group was prepared in the same manner as in Example 1, except that 4,4,4-trifluoro-1-butanol was used instead of 1-butanol in the second step of Example 1. The introduction rate of the succinic anhydride unit was 2.6 mol%, and the introduction rate of the ester bond-containing group introduced by the acyl substitution reaction was 1.3 mol%. Therefore, the content of the non-covalently bondable functional group can be estimated as 2.6 mol% x 2 - 1.3 mol% = 3.9 mol%, and the content of the ionic group (carboxylate anion group) in the 3.9 mol% was 2.6 mol%, and the content of the hydrogen-bondable functional group (carboxy group) was 1.3 mol%.

Claims

A modified group-containing hydrogenated block copolymer having at least one aromatic vinyl polymer block and at least one modified group-containing hydrogenated conjugated diene polymer block,
The modified group-containing hydrogenated conjugated diene polymer block is a hydrogenated conjugated diene polymer block having a unit derived from a conjugated diene monomer to which a non-covalently bondable modified group has been introduced.
The modified group-containing hydrogenated block copolymer according to claim 1, wherein the non-covalently bondable modified group is at least one functional group selected from a functional group capable of hydrogen bonding, a functional group capable of coordinate bonding, and a functional group capable of ionic bonding.
The modified group-containing hydrogenated block copolymer according to claim 1 or 2, wherein the non-covalently bondable modified group is at least one group selected from an ionic group formed of an acid salt, an ionic group formed of a base salt, an acidic group, and a basic group.
The modified group-containing hydrogenated block copolymer according to any one of claims 1 to 3, wherein the modified group-containing hydrogenated conjugated diene polymer block is a modified group-containing hydrogenated isoprene polymer block, a modified group-containing hydrogenated butadiene polymer block, or a modified group-containing hydrogenated butadiene-isoprene copolymer block.
The modified group-containing hydrogenated block copolymer according to any one of claims 1 to 4, in which the proportion of units derived from aromatic vinyl monomers is 5 to 50 mass %.
The modified group-containing hydrogenated block copolymer according to any one of claims 1 to 5, having a weight average molecular weight of 30,000 to 500,000.
The modified group-containing hydrogenated block copolymer according to any one of claims 1 to 6, in which the hydrogenation rate of the modified group-containing hydrogenated conjugated diene polymer block is 70 mol % or more.
The modified group-containing hydrogenated block copolymer according to any one of claims 1 to 7, wherein the introduction rate of the non-covalently bondable modified group is 1 to 15 mol % relative to 100 mol % of the units derived from the conjugated diene monomer constituting the modified group-containing hydrogenated conjugated diene polymer block.
The modified group-containing hydrogenated block copolymer according to any one of claims 1 to 8, wherein the modified group-containing hydrogenated conjugated diene polymer block is a hydrogenated conjugated diene polymer block having units derived from a conjugated diene monomer into which the non-covalently bondable modified group and an ester bond-containing functional group have been introduced.
The modified group-containing hydrogenated block copolymer according to claim 9, wherein the introduction rate of the ester bond-containing functional group is 0.1 to 30 mol % relative to 100 mol % of the units derived from the conjugated diene monomer constituting the modified group-containing hydrogenated conjugated diene polymer block.
The hydrogenated block copolymer containing a modifying group according to any one of claims 1 to 10, wherein the aromatic vinyl polymer block is a polystyrene block.
A method for producing the modifying group-containing hydrogenated block copolymer according to any one of claims 1 to 11, comprising the steps of:
a modification step of subjecting a base polymer (A1) having at least one aromatic vinyl polymer block and at least one conjugated diene polymer block [D(A1)] to a modification treatment for introducing a non-covalently bondable modifying group, thereby obtaining a modifying group-containing block copolymer (B1) in which at least a portion of units derived from a conjugated diene monomer constituting at least one of the conjugated diene polymer blocks [D(A1)] is a unit derived from a conjugated diene monomer having the non-covalently bondable modifying group; and
A method for producing a modifying group-containing hydrogenated block copolymer, comprising a hydrogenation step of subjecting the modifying group-containing block copolymer (B1) to a hydrogenation treatment.