Copolymer, method for producing copolymer, and low molecular weight compound-impregnated particle

Abstract

To provide useful improvement concerning a copolymer as a star polymer and a method for producing the same.SOLUTION: A copolymer includes: a plurality of block segments A derived from a macromonomer (A); a plurality of block segments B comprising only a constitutional unit (b) derived from a vinyl monomer (B) having one vinyl group in a molecule; and a plurality of block segments C having a rate of a constitutional unit derived from a vinyl monomer (C1) having two or more vinyl groups in a molecule of 10 mol% or more, wherein the plurality of block segments C has a bridge structure obtained by bridging mutually, and the bridge structure has an iodine terminal.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a copolymer, a method for producing the copolymer, and particles impregnated with a low molecular weight compound. [Background technology]

[0002] Star polymers, which have multiple arms radiating from a central core, have attracted considerable interest in various fields, including bioimaging, biosensing, catalysis, energy storage, and agricultural applications. Living radical polymerization is a widely used method for producing star polymers.

[0003] As living radical polymerization methods, Patent Document 1 discloses a reversible transfer catalyzed polymerization method (RTCP method), and Patent Documents 2 and 3 disclose a reversible complexation-mediated polymerization method (RCMP method). However, these methods make it difficult to synthesize polymers with high molecular weights, such as number-average molecular weights of 100,000 or more. Patent Document 4 discloses a copolymer having a three or more arm structure, which has a block polymer chain including a block segment composed of a structural unit derived from a monomer having two or more vinyl groups in the molecule, the block segment forming a crosslinked structure at the center of the copolymer, and the crosslinked structure having an iodine terminal. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] International Publication No. 2008 / 139980 [Patent Document 2] International Publication No. 2011 / 016166 [Patent Document 3] International Publication No. 2013 / 027419 [Patent Document 4] Japanese Patent Publication No. 2022-153259 Summary of the Invention [Problem to be solved by the invention]

[0005] A primary object of the present invention is to provide useful improvements in copolymers as star polymers and methods for their preparation. [Means for solving the problem]

[0006] The present invention includes the following configurations. [1] A polymer having a plurality of block segments A derived from a macromonomer (A), a plurality of block segments B consisting only of structural units (b) derived from a vinyl monomer (B) having one vinyl group in the molecule, and a plurality of block segments C in which the proportion of structural units (c1) derived from a vinyl monomer (C1) having two or more vinyl groups in the molecule is 10 mol % or more, A copolymer, wherein the plurality of block segments C are crosslinked to one another to form a crosslinked structure, and the crosslinked structure has an iodine terminal. [2] The copolymer according to [1], wherein the block segment B has a branched structure, and the main chain and the branched chain are the same structural units. [3] The copolymer according to [1] or [2], wherein the macromonomer (A) is a macromonomer represented by the following formula (I): [ka] (In formula (I), R and R 1 ~R n are each independently a hydrogen atom, an alkyl group, a cycloalkyl group, an aryl group, or a heterocyclic group. Z is a hydrogen atom or a group derived from a radical polymerization initiator. X 1 ~X n are each independently a hydrogen atom or a methyl group, and n is an integer of 2 to 10,000. [4] The copolymer according to any one of [1] to [3], wherein the vinyl monomer (B) is at least one selected from the group consisting of a styrene-based monomer, a methacrylate-based monomer, and an acrylate-based monomer. [5] obtaining a macroinitiator consisting of a block copolymer by polymerizing a polymerizable composition (M11) containing a macromonomer (A), a vinyl monomer (B) having one vinyl group in the molecule, and an organic iodine compound (D); polymerizing a polymerizable composition (M21) comprising the macroinitiator and a vinyl monomer (C), The method for producing a copolymer, wherein the vinyl monomer (C) contains 10 mol % or more of a vinyl monomer (C1) having two or more vinyl groups in the molecule. [6] The method for producing a copolymer according to [5], wherein the macromonomer (A) is a macromonomer represented by the following formula (I): [ka] (In formula (I), R and R 1 ~R n are each independently a hydrogen atom, an alkyl group, a cycloalkyl group, an aryl group, or a heterocyclic group. Z is a hydrogen atom or a group derived from a radical polymerization initiator. X 1 ~X n are each independently a hydrogen atom or a methyl group, and n is an integer of 2 to 10,000. [7] The method for producing a copolymer according to [5] or [6], wherein the polymerizable composition (M11) further contains either or both of a catalyst (E) and an azo-based radical polymerization initiator (F). [8] The method for producing a copolymer according to any one of [5] to [7], wherein the polymerizable composition (M21) further contains a catalyst (G). [9] The method for producing a copolymer according to any one of [5] to [8], further comprising purifying the composition obtained by polymerizing the polymerizable composition (M11) to recover the macroinitiator.

[10] The method for producing a copolymer according to any one of [5] to [8], wherein the composition obtained by polymerizing the polymerizable composition (M11) is not purified, and the vinyl monomer (C1) is added thereto to carry out polymerization as the polymerizable composition (M21).

[11] Polymerizing a polymerizable composition (M12) containing a macromonomer (A), a vinyl monomer (B) having one vinyl group in the molecule, an azo-based radical polymerization initiator (F), and iodine to obtain a macroinitiator consisting of a block copolymer; polymerizing a polymerizable composition (M22) comprising the macroinitiator and a vinyl monomer (C), The method for producing a copolymer, wherein the vinyl monomer (C) contains 10 mol % or more of a vinyl monomer (C1) having two or more vinyl groups in the molecule.

[12] The method for producing a copolymer according to

[11] , wherein the macromonomer (A) is a macromonomer represented by the following formula (I): [ka] (In formula (I), R and R 1 ~R n are each independently a hydrogen atom, an alkyl group, a cycloalkyl group, an aryl group, or a heterocyclic group. Z is a hydrogen atom or a group derived from a radical polymerization initiator. X 1 ~X n are each independently a hydrogen atom or a methyl group, and n is an integer of 2 to 10,000.

[13] The method for producing a copolymer according to

[11] or

[12] , wherein the polymerizable composition (M12) further contains a catalyst (E).

[14] The method for producing a copolymer according to any one of

[11] to

[13] , wherein the polymerizable composition (M22) further contains a catalyst (G).

[15] The method for producing a copolymer according to any one of

[11] to

[14] , further comprising purifying a composition obtained by polymerizing the polymerizable composition (M12) to recover the macroinitiator.

[16] The method for producing a copolymer according to any one of

[11] to

[14] , wherein the composition obtained by polymerizing the polymerizable composition (M12) is not purified, and the vinyl monomer (C1) is added thereto to polymerize the composition to form the polymerizable composition (M22).

[17] The method for producing a copolymer according to any one of [5] to

[16] , wherein the vinyl monomer (B) is at least one selected from the group consisting of a styrene-based monomer, a methacrylate-based monomer, and an acrylate-based monomer.

[18] A low-molecular-weight compound-impregnated particle obtained by impregnating the copolymer according to any one of [1] to [4] with a low-molecular-weight compound having a molecular weight of 1,000 or less. [Effects of the Invention]

[0007] The present invention provides beneficial improvements in copolymers as star polymers and methods for their preparation. [Brief explanation of the drawings]

[0008] [Figure 1] FIG. 1 is an explanatory diagram schematically illustrating one-pot synthesis and two-pot synthesis in a copolymer production method according to an embodiment. [Figure 2] Figure 2(a) is a GPC chromatogram obtained by measuring the polymerization in step (I-2) of Experimental Example 1 using the GPC peak separation method, Figure 2(b) is a GPC chromatogram obtained by measuring the polymerization in step (I-2) of Experimental Example 2 using the GPC peak separation method, and Figure 2(c) is a diagram showing the particle size measurement results of the copolymers of Experimental Examples 1 and 2. [Figure 3] 3(a) to 3(d) are diagrams showing GPC chromatograms obtained by measuring the polymerization in step (I-2) of Experimental Examples 3 to 6 by the GPC peak separation method. [Figure 4] Figure 4(a) is a GPC chromatogram obtained by measuring the polymerization in step (I-2) of Experimental Example 7 using the GPC peak separation method, Figure 4(b) is a GPC chromatogram obtained by measuring the polymerization in step (I-2) of Experimental Example 8 using the GPC peak separation method, and Figure 4(c) is a diagram showing the particle size measurement results of the copolymers of Experimental Examples 7 and 8. [Figure 5] Figure 5(a) is a GPC chromatogram obtained by measuring the polymerization in step (I-2) of Experimental Example 9 using the GPC peak separation method, and Figure 5(b) is a diagram showing the particle size measurement results of the copolymer of Experimental Example 9. [Figure 6]1 shows the results of measuring the ultraviolet-visible transmission spectra (200 to 800 nm) of the PMMA films of Experimental Examples 12 to 15. DETAILED DESCRIPTION OF THE INVENTION

[0009] Hereinafter, the embodiments for carrying out the present invention will be described in detail, but the present invention is not limited to the following description and can be carried out in various modified forms within the scope of the gist thereof.

[0010] [Terminology] The following definitions of terms apply throughout the specification and claims. The term "structural unit" refers to a structural unit derived from a monomer, i.e., a structural unit formed by polymerizing a monomer, or a structural unit in which a portion of the structural unit is converted into a different structure by treating the polymer. "Vinyl monomer" means a compound containing at least one vinyl group (carbon-carbon unsaturated double bond). "(Meth)acrylate" refers to "acrylate" or "methacrylate". Furthermore, unless otherwise specified, in this specification, a numerical range expressed using "to" means a range that includes the numerical values ​​written before and after "to" as the lower limit and upper limit.

[0011] [Copolymer] The copolymer according to the present embodiment comprises a plurality of block segments A derived from a macromonomer (A), a block segment B consisting solely of structural units (b) derived from a vinyl monomer (B) having one vinyl group in the molecule, and a plurality of block segments C in which the proportion of structural units (c1) derived from a vinyl monomer (C1) having two or more vinyl groups in the molecule is 10 mol % or more. The plurality of block segments C are crosslinked to one another to form a crosslinked structure, and the crosslinked structure has an iodine terminal.

[0012] In this specification, a block segment present at the center of a copolymer is referred to as a "core structure," and a block segment connected to the core structure is also referred to as an "arm structure," and a copolymer having such a core structure and arm structure is also referred to as a "star polymer." In a copolymer according to one example of the embodiment, the core structure has a crosslinked structure formed by block segments C. The arm structures are each composed of block segments A and B, and three or more arm structures are connected to the core structure to form a star polymer. In one example, each block segment B in a plurality of arm structures, each of which is formed by linking one block segment A and one block segment B, is connected to a block segment C constituting the core structure to form a star polymer.

[0013] (Macromonomer (A)) The macromonomer (A) that forms the block segment A is preferably a macromonomer represented by formula (I). In formula (I), "..." represents the state in which the monomer units are polymerized. The macromonomer (A) has a group having a radical-reactive unsaturated double bond at one end of the poly(meth)acrylate segment.

[0014] [ka]

[0015] In formula (I), R and R 1 ~R n are each independently a hydrogen atom, an alkyl group, a cycloalkyl group, an aryl group, or a heterocyclic group. Z is a hydrogen atom or a group derived from a radical polymerization initiator. X 1 ~X n are each independently a hydrogen atom or a methyl group, and n is an integer of 2 to 10,000.

[0016] R and R 1 ~R n The alkyl group, cycloalkyl group, aryl group and heterocyclic group may have a substituent. R and R 1 ~R n is preferably at least one selected from an alkyl group and a cycloalkyl group, more preferably an alkyl group.

[0017] R and R 1 ~R n Examples of the alkyl group include branched or linear alkyl groups having 1 to 20 carbon atoms. Specific examples include methyl, ethyl, n-propyl, i-propyl, n-butyl, t-butyl, i-butyl, pentyl, hexyl, heptyl, octyl, nonyl, decyl, undecyl, dodecyl, tridecyl, tetradecyl, pentadecyl, hexadecyl, heptadecyl, octadecyl, nonadecyl, and icosyl. From the perspective of ease of polymerization control, the alkyl group is preferably methyl, ethyl, n-propyl, i-propyl, n-butyl, t-butyl, pentyl, hexyl, heptyl, or octyl, more preferably methyl, ethyl, n-propyl, i-propyl, n-butyl, or t-butyl, and particularly preferably methyl.

[0018] R and R 1 ~R n Examples of the cycloalkyl group include cycloalkyl groups having 3 to 20 carbon atoms. Specific examples include a cyclopropyl group, a cyclobutyl group, a cyclopentyl group, a cyclohexyl group, a cycloheptyl group, a cyclooctyl group, and an adamantyl group. As the cycloalkyl group, a cyclopropyl group, a cyclobutyl group, and an adamantyl group are preferred from the viewpoint of ease of controlling polymerization.

[0019] R and R 1 ~R n Examples of the aryl group include aryl groups having 6 to 18 carbon atoms. Specific examples of the aryl group having 6 to 18 carbon atoms include a phenyl group, a benzyl group, and a naphthyl group.

[0020] R and R 1 ~R nExamples of the heterocyclic group include heterocyclic groups having 5 to 18 carbon atoms. Examples of heteroatoms contained in the heterocyclic group include an oxygen atom, a nitrogen atom, and a sulfur atom. Specific examples of the heterocyclic group include a γ-lactone group, an ε-caprolactone group, and a morpholine group.

[0021] R and R 1 ~R n Examples of the substituents in the formula (I) include, independently, an alkyl group, an aryl group, a carboxy group, an alkoxycarbonyl group (-COOR'), a carbamoyl group (-CONR'R''), a cyano group, a hydroxy group, an amino group, an amide group (-NR'R''), a halogen atom, an allyl group, an epoxy group, an alkoxy group (-OR'), and a group exhibiting hydrophilicity or ionicity. R' and R'' are, independently, the same groups as R (excluding heterocyclic groups).

[0022] R and R 1 ~R n An example of the alkoxycarbonyl group as a substituent of the above is a methoxycarbonyl group. R and R 1 ~R n Examples of the carbamoyl group as a substituent include an N-methylcarbamoyl group and an N,N-dimethylcarbamoyl group. R and R 1 ~R n Examples of the halogen atom as a substituent include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom. R and R 1 ~R n Examples of the alkoxy group as the substituent include alkoxy groups having 1 to 12 carbon atoms, and a specific example is a methoxy group. R and R 1 ~R n Examples of the hydrophilic or ionic group as the substituent include an alkali salt of a carboxy group or an alkali salt of a sulfoxyl group, a poly(alkylene oxide) group such as a polyethylene oxide group or a polypropylene oxide group, and a cationic substituent such as a quaternary ammonium base.

[0023] X 1 ~X n are each independently a hydrogen atom or a methyl group, and a methyl group is preferred. In the macromonomer (A), X is used from the viewpoint of ease of synthesis. 1 ~X n It is preferable that at least half of the groups are methyl groups.

[0024] Z is a hydrogen atom or a group (fragment) derived from a radical polymerization initiator, and examples thereof include groups similar to the terminal groups of polymers obtained by known radical polymerization. When no radical polymerization initiator is used during production, Z is a hydrogen atom.

[0025] n means the number of monomer units in one molecule of macromonomer (A). n is an integer of 2 to 10,000, preferably an integer of 10 to 1,000, and more preferably an integer of 30 to 500.

[0026] The number average molecular weight (Mn) of the macromonomer (A) is preferably 1,000 or more, more preferably 3,000 or more, and even more preferably 5,000 or more. The Mn of the macromonomer (A) is preferably 1,000,000 or less, more preferably 500,000 or less, even more preferably 300,000 or less, and particularly preferably 100,000 or less. The preferred lower and upper limits of Mn of the macromonomer (A) can be arbitrarily combined; for example, 1,000 to 1,000,000 is preferred, 1,000 to 500,000 is more preferred, 3,000 to 300,000 is more preferred, and 5,000 to 100,000 is particularly preferred. When the Mn of the macromonomer (A) is equal to or greater than the lower limit of the aforementioned range, the physical properties of the block copolymer, particularly the mechanical properties, tend to be excellent.

[0027] The molecular weight distribution (Mw / Mn) of the macromonomer (A) is preferably 1.0 or more, more preferably 1.5 or more. Mw / Mn is preferably 5.0 or less, more preferably 3.0 or less. The preferred lower and upper limits of Mw / Mn can be arbitrarily combined. For example, a range of 1.0 to 5.0 is preferred, and a range of 1.5 to 3.0 is more preferred. Here, Mw means weight average molecular weight. Mn and Mw of the macromonomer (A) are calculated from a calibration curve of polymethyl methacrylate (PMMA) using gel permeation chromatography (GPC).

[0028] The macromonomer (A) contains a structural unit derived from a vinyl monomer, but the vinyl monomer for obtaining the macromonomer (A) can be selected independently of the vinyl monomer (B) as a copolymer component described below. Examples of vinyl monomers for obtaining the macromonomer (A) include methyl (meth)acrylate, ethyl (meth)acrylate, n-propyl (meth)acrylate, isopropyl (meth)acrylate, n-butyl (meth)acrylate, isobutyl (meth)acrylate, t-butyl (meth)acrylate, isoamyl (meth)acrylate, hexyl (meth)acrylate, octyl (meth)acrylate, lauryl (meth)acrylate, dodecyl (meth)acrylate, stearyl (meth)acrylate, phenyl (meth)acrylate, benzyl (meth)acrylate, glycidyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, 2-hydroxybenzoates, Examples include ethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 2-hydroxybutyl (meth)acrylate, 3-hydroxybutyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate, polyethylene glycol (meth)acrylate, polypropylene glycol (meth)acrylate, methoxyethyl (meth)acrylate, ethoxyethyl (meth)acrylate, n-butoxyethyl (meth)acrylate, isobutoxyethyl (meth)acrylate, t-butoxyethyl (meth)acrylate, phenoxyethyl (meth)acrylate, nonylphenoxyethyl (meth)acrylate, and 3-methoxybutyl (meth)acrylate.

[0029] Commercially available products of these vinyl monomers include, for example, PLACCEL FM (trade name, (meth)acrylate caprolactone addition monomer, manufactured by Daicel Chemical Industries, Ltd.), BLEMMER PME-100 (trade name, methoxypolyethylene glycol methacrylate (having two ethylene glycol chains), manufactured by NOF Corporation), BLEMMER PME-200 (trade name, methoxypolyethylene glycol methacrylate (having four ethylene glycol chains), manufactured by NOF Corporation), and BLEMMER PME-400 (trade name, methoxypolyethylene glycol methacrylate (having nine ethylene glycol chains), manufactured by NOF Corporation). Examples include BLEMMER 50POEP-800B (trade name, octoxypolyethylene glycol-polypropylene glycol-methacrylate (having 8 ethylene glycol chains and 6 propylene glycol chains), manufactured by NOF Corporation), BLEMMER 20ANEP-600 (trade name, nonylphenoxy(ethylene glycol-polypropylene glycol) monoacrylate, manufactured by NOF Corporation), BLEMMER AME-100 (trade name, manufactured by NOF Corporation), BLEMMER AME-200 (trade name, manufactured by NOF Corporation), and BLEMMER 50AOEP-800B (trade name, manufactured by NOF Corporation).

[0030] As the vinyl monomer for obtaining the macromonomer (A), methacrylate is preferred from the viewpoint of ease of polymerization control. As the methacrylate, from the viewpoint of the transparency of the molded body or coating film, methyl methacrylate, n-butyl methacrylate, lauryl methacrylate, dodecyl methacrylate, stearyl methacrylate, 2-ethylhexyl methacrylate, glycidyl methacrylate, 2-hydroxyethyl methacrylate, and 4-hydroxybutyl methacrylate are preferred, methyl methacrylate, n-butyl methacrylate, and 2-ethylhexyl methacrylate are more preferred, and methyl methacrylate is particularly preferred.

[0031] In order to obtain a copolymer having excellent resistance to residence degradation, the vinyl monomer for obtaining the macromonomer (A) preferably contains an acrylate in addition to a methacrylate. Preferred acrylates are methyl acrylate, ethyl acrylate, n-propyl acrylate, isopropyl acrylate, n-butyl acrylate, isobutyl acrylate, and t-butyl acrylate, with methyl acrylate being preferred from the viewpoint of availability.

[0032] The vinyl monomer for obtaining the macromonomer (A) may include other vinyl monomers other than methacrylates and acrylates. The other vinyl monomer is preferably an unsaturated carboxylic acid, such as acrylic acid, methacrylic acid, maleic acid, or maleic anhydride. The vinyl monomers for obtaining the macromonomer (A) may be used singly or in combination of two or more.

[0033] The content of methacrylate in the total amount of vinyl monomers used to obtain macromonomer (A) is preferably 80 to 99.5 mass%, more preferably 82 to 99 mass%, even more preferably 84 to 99 mass%, and particularly preferably 85 to 99 mass%, based on the total mass of vinyl monomers, from the viewpoint of resistance to retention degradation of the copolymer.

[0034] The content of the acrylate in the total amount of vinyl monomers for obtaining the macromonomer (A) is preferably from 0.1 to 20 mass %, more preferably from 1 to 15 mass %, based on the total mass of the vinyl monomers. As the macromonomer (A), one type may be used alone, or two or more types may be used in combination.

[0035] Examples of methods for producing the macromonomer (A) include a method using a cobalt chain transfer agent (U.S. Patent No. 4,680,352), a method using an α-substituted unsaturated compound such as α-bromomethylstyrene as a chain transfer agent (WO 88 / 04304), a method of chemically bonding a polymerizable group (JP-A No. 60-133007, U.S. Patent No. 5,147,952), and a method using thermal decomposition (JP-A No. 11-240854). As a method for producing macromonomer (A), a method using a cobalt chain transfer agent is preferred because it requires fewer production steps and uses a catalyst with a high chain transfer constant. By using a cobalt chain transfer agent with a high chain transfer constant, macromonomer (A) with a controlled molecular weight can be obtained with a small amount.

[0036] Examples of methods for producing the macromonomer (A) using a cobalt chain transfer agent include aqueous dispersion polymerization methods such as bulk polymerization, solution polymerization, suspension polymerization, and emulsion polymerization. Among these, aqueous dispersion polymerization methods such as suspension polymerization and emulsion polymerization are preferred, with suspension polymerization being particularly preferred, from the viewpoint of simplifying the recovery process of the macromonomer (A).

[0037] As the cobalt chain transfer agent, those described in U.S. Patent No. 4,680,352 can be used. As the cobalt chain transfer agent, a monovalent cobalt complex obtained by reacting cobalt (II) acetate, diphenylglyoxime, and boron trifluoride diethyl ether complex can also be used. The amount of the cobalt chain transfer agent used is preferably 0.1 to 50 ppm, more preferably 1 to 25 ppm, based on the total amount of vinyl monomers used in the production of the macromonomer (A).

[0038] Examples of solvents that can be used when obtaining macromonomer (A) by solution polymerization include hydrocarbon solvents such as toluene, ether solvents such as diethyl ether and tetrahydrofuran, halogenated hydrocarbon solvents such as dichloromethane and chloroform, ketone solvents such as acetone, alcohol solvents such as methanol, nitrile solvents such as acetonitrile, vinyl ester solvents such as ethyl acetate, carbonate solvents such as ethylene carbonate, and supercritical carbon dioxide. These solvents may be used alone or in combination.

[0039] Specific examples of the method for producing the macromonomer (A) include the following methods. A raw material composition containing a dispersant, a water-soluble salt, a vinyl monomer, a cobalt chain transfer agent, and a polymerization initiator is prepared. The raw material composition is subjected to suspension polymerization at 70 to 100°C for 2 to 7 hours to prepare an aqueous suspension containing macromonomer (A). The macromonomer (A) is recovered from the resulting aqueous suspension by filtration.

[0040] The macromonomer (A) is preferably a macromonomer obtained by suspension polymerization of a vinyl monomer using a cobalt chain transfer agent. For the production of the copolymer, a powder obtained by recovering and purifying the macromonomer (A) produced by the above-mentioned method may be used, or an aqueous suspension containing the macromonomer (A) synthesized by suspension polymerization may be used as is. Commercially available products may be used as the macromonomer (A). Examples of commercially available products of the macromonomer (A) include the ELVACITE (registered trademark) series (manufactured by Lucite International).

[0041] (Vinyl Monomer (B)) The vinyl monomer (B) forming the block segment B is a vinyl monomer having one vinyl group in the molecule. Examples of the vinyl monomer (B) include the same vinyl monomers as those exemplified as the vinyl monomers for obtaining the macromonomer (A). The vinyl monomer (B) may be used alone or in combination of two or more kinds.

[0042] As the vinyl monomer (B), from the viewpoint of polymerization control, at least one selected from the group consisting of styrene-based monomers, methacrylate-based monomers and acrylate-based monomers is preferred. Examples of styrene-based monomers include styrene, α-methylstyrene, o-, m-, or p-methylstyrene, o-, m-, or p-methoxystyrene, o-, m-, or p-butoxystyrene, o-, m-, or p-chloromethylstyrene, o-, m-, or p-chlorostyrene, o-, m-, or p-hydroxystyrene, o-, m-, or p-styrenesulfonic acid and derivatives thereof, sodium o-, m-, or p-styrenesulfonate, and o-, m-, or p-styreneboronic acid and derivatives thereof. Among these, styrene is preferred from the viewpoint of polymerization control.

[0043] Examples of methacrylate monomers and acrylate monomers include methyl (meth)acrylate, ethyl (meth)acrylate, n-propyl (meth)acrylate, isopropyl (meth)acrylate, n-butyl (meth)acrylate, isobutyl (meth)acrylate, t-butyl (meth)acrylate, isoamyl (meth)acrylate, hexyl (meth)acrylate, octyl (meth)acrylate, lauryl (meth)acrylate, dodecyl (meth)acrylate, stearyl (meth)acrylate, phenyl (meth)acrylate, benzyl (meth)acrylate, glycidyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 2-hydroxybutyl (meth)acrylate, and 3-hydroxybutyl (meth)acrylate. Preferred are 4-hydroxybutyl (meth)acrylate, polyethylene glycol (meth)acrylate, polypropylene glycol (meth)acrylate, methoxyethyl (meth)acrylate, ethoxyethyl (meth)acrylate, n-butoxyethyl (meth)acrylate, isobutoxyethyl (meth)acrylate, t-butoxyethyl (meth)acrylate, phenoxyethyl (meth)acrylate, nonylphenoxyethyl (meth)acrylate, and 3-methoxybutyl (meth)acrylate, and more preferred are methyl acrylate, ethyl acrylate, n-butyl acrylate, lauryl acrylate, dodecyl acrylate, stearyl acrylate, 2-ethylhexyl acrylate, glycidyl acrylate, 2-hydroxyethyl acrylate, 4-hydroxybutyl acrylate, and methoxyethyl acrylate.

[0044] (Vinyl Monomer (C)) The proportion of the structural unit (c1) derived from a vinyl monomer (C1) having two or more vinyl groups in the molecule relative to the total amount of structural units (c) derived from the vinyl monomer (C) constituting the block segment C is 10 mol% or more, preferably 20 mol% or more, more preferably 30 mol% or more, even more preferably 50 mol% or more, and particularly preferably 80 mol% or more. If the proportion of the structural unit (c1) in the block segment C is equal to or greater than the above-mentioned lower limit, the molecular weight of the copolymer increases. The upper limit of the proportion of the structural unit (c1) in the block segment C can be set to 100 mol%. The structural units (c) derived from the vinyl monomer (C) preferably contain 10 mol % or more of structural units derived from divinyl monomers or structural units derived from trivinyl monomers, and more preferably contain 10 mol % or more of structural units derived from divinyl monomers.

[0045] Examples of the vinyl monomer (C1) include divinylbenzene, dibromodivinylbenzene, dimethoxydivinylbenzene, diethoxydivinylbenzene, dipropoxydivinylbenzene, dibutoxydivinylbenzene, dipentyloxydivinylbenzene, dihexyloxydivinylbenzene, diheptyloxydivinylbenzene, dioctyloxydivinylbenzene, dinonyloxydivinylbenzene, didecyloxydivinylbenzene, di(2-ethylhexyl)oxydivinylbenzene, ethylene glycol di(meth)acrylate, 1,3-butylene glycol di(meth)acrylate, 1,6-hexanediol di(meth)acrylate, diethylene glycol di (meth)acrylate, triethylene glycol di(meth)acrylate, tetraethylene glycol di(meth)acrylate, tripropylene glycol di(meth)acrylate, allyl (meth)acrylate, N,N'-methylenebis(meth)acrylamide, glycerol tri(meth)acrylate, pentaerythritol di(meth)acrylate, pentaerythritol tetra(meth)acrylate, diurethane di(meth)acrylate, bis(2-methacryloyl)oxyethyl disulfide, bis(2-acryloyl)oxyethyl disulfide, trimethylolpropane tri(meth)acrylate, and pentaerythritol tri(meth)acrylate.

[0046] As the vinyl monomer (C1), from the viewpoint of availability, divinylbenzene, ethylene glycol di(meth)acrylate, 1,3-butylene glycol di(meth)acrylate, 1,6-hexanediol di(meth)acrylate, diethylene glycol di(meth)acrylate, triethylene glycol di(meth)acrylate, tetraethylene glycol di(meth)acrylate, tripropylene glycol di(meth)acrylate, and trimethylolpropane tri(meth)acrylate are preferred. The monomer (C1) may be used alone or in combination of two or more kinds.

[0047] The vinyl monomer (C) forming the block segment C may contain a vinyl monomer (C2) having one vinyl group in the molecule. Examples of the vinyl monomer (C2) include the same monomers as those exemplified as the vinyl monomer (B). These may be used alone or in combination of two or more.

[0048] From the viewpoint of controlling the polymerization, the vinyl monomer (C2) is preferably at least one selected from the group consisting of styrene-based monomers, methacrylate-based monomers and acrylate-based monomers. The styrene monomer is preferably styrene. Preferred (meth)acrylate monomers include methyl (meth)acrylate, ethyl (meth)acrylate, n-propyl (meth)acrylate, isopropyl (meth)acrylate, n-butyl (meth)acrylate, isobutyl (meth)acrylate, t-butyl (meth)acrylate, isoamyl (meth)acrylate, hexyl (meth)acrylate, octyl (meth)acrylate, lauryl (meth)acrylate, dodecyl (meth)acrylate, stearyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, glycidyl (meth)acrylate, 2-hydroxyethyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate, polyethylene glycol (meth)acrylate and its alkyl ethers, and methoxyethyl (meth)acrylate.

[0049] The block segment C may contain a structural unit (c2) derived from the vinyl monomer (C2) in addition to the structural unit (c1) derived from the vinyl monomer (C1). In the case of the one-pot synthesis described below, the structural unit derived from the unreacted vinyl monomer (B) contained in the polymerizable compositions (M21) and (M22) is the structural unit (c2) derived from the vinyl monomer (C2). In the copolymer according to this embodiment, the boundary between block segment B and block segment C is defined as the space between the structural unit (c1) closest to the arm structure in the core structure and the structural unit (b) bonded to that arm structure side.

[0050] The proportion of the structural unit (a) relative to the total amount of all structural units in the copolymer according to the embodiment is preferably 2% by mass or more, more preferably 5% by mass or more, and even more preferably 10% by mass or more. The proportion of the structural unit (a) is preferably 60% by mass or less, more preferably 50% by mass or less, and even more preferably 40% by mass or less. The preferred lower and upper limits of the proportion of the structural unit (a) can be arbitrarily combined. For example, 2 to 60% by mass is preferred, 5 to 50% by mass is more preferred, and 10 to 40% by mass is even more preferred. When the proportion of the structural unit (a) is equal to or greater than the lower limit, a star polymer with excellent dispersion stability can be obtained. When the proportion of the structural unit (a) is equal to or less than the upper limit, the impregnation amount of the low-molecular-weight compound can be increased.

[0051] The proportion of the structural unit (b) relative to the total amount of all structural units in the copolymer according to the embodiment is preferably 30% by mass or more, more preferably 40% by mass or more, and even more preferably 50% by mass or more. The proportion of the structural unit (b) is preferably 90% by mass or less, more preferably 80% by mass or less, and even more preferably 70% by mass or less. The preferred lower and upper limits of the proportion of the structural unit (b) can be arbitrarily combined. For example, 10 to 90% by mass is preferred, 20 to 80% by mass is more preferred, and 30 to 70% by mass is more preferred. When the proportion of the structural unit (b) is equal to or greater than the lower limit, the impregnation amount of the low-molecular-weight compound can be increased. When the proportion of the structural unit (b) is equal to or less than the upper limit, a star polymer with excellent dispersion stability can be obtained.

[0052] The proportion of the structural unit (c) relative to the total amount of all structural units in the copolymer according to the embodiment is preferably 5% by mass or more, more preferably 10% by mass or more, and even more preferably 20% by mass or more. The proportion of the structural unit (c) is preferably 80% by mass or less, more preferably 70% by mass or less, and even more preferably 60% by mass or less. The preferred lower and upper limits of the proportion of the structural unit (c) can be arbitrarily combined. For example, 5 to 80% by mass is preferred, 10 to 70% by mass is more preferred, and 20 to 60% by mass is even more preferred. When the proportion of the structural unit (c) is equal to or greater than the lower limit, the impregnation amount of the low-molecular-weight compound can be increased. When the proportion of the structural unit (c) is equal to or less than the upper limit, a star polymer with excellent dispersion stability can be obtained.

[0053] The proportion of the structural unit (c1) relative to the total amount of all structural units in the copolymer according to the embodiment is preferably 2% by mass or more, more preferably 5% by mass or more, and even more preferably 10% by mass or more. The proportion of the structural unit (c1) is preferably 50% by mass or less, more preferably 40% by mass or less, and even more preferably 30% by mass or less. The preferred lower and upper limits of the proportion of the structural unit (c1) can be arbitrarily combined. For example, 2 to 50% by mass is preferred, 5 to 40% by mass is more preferred, and 10 to 30% by mass is even more preferred. When the proportion of the structural unit (c1) is at least the lower limit, a particulate star polymer can be obtained. When the proportion of the structural unit (c1) is at most the upper limit, the impregnation amount of the low-molecular-weight compound can be increased.

[0054] In the copolymer according to the embodiment, substantially all of the constituent units of the block segments are derived from vinyl monomers, but may contain constituent units other than those derived from vinyl monomers as long as the effects of the present invention are not significantly affected.

[0055] In a copolymer according to one embodiment, each arm structure has a branched structure, and typically, the block segment B has a branched structure. The number of branched structures in the copolymer, i.e., the number of branched chains, is preferably 1 or more on average per molecule, more preferably 2 or more, and even more preferably 5 or more. If the number of branched chains is equal to or greater than the lower limit, the impregnation of low molecular weight compounds is improved, and the amount of impregnation can be increased. The more branched chains there are, the better.

[0056] In a block segment having a branched structure, the main chain and the branched chains are preferably composed of the same structural units. Note that "the main chain and the branched chains are composed of the same structural units" means that the structural units of the branched chains are the same as the structural units of the main chain of the block segment in which the branching occurs. A block segment having a branched structure in which the main chain and the branched chains are composed of the same structural units is not limited to one composed of only one type of structural unit. For example, it may be a block segment having a main chain composed of two or more types of structural units and a branched chain composed of the same two or more types of structural units as the main chain. The copolymer has a branched structure, which reduces viscosity, and the main chain and branched chain of the block segment are made of the same structural unit, which allows the properties of each structural unit to be fully expressed as the block segment.

[0057] When the copolymer has a branched structure, the branched structure can be confirmed by GPC-TDA measurement using a viscosity detector or GPC-MALS measurement using a multi-angle light scattering detector. Unreacted vinyl groups in the crosslinked structure can be identified by NMR measurement. For example, 13 If a C-NMR measurement is performed and methine groups adjacent to the quaternary carbon are detected at 38 to 41 ppm, it can be determined that the copolymer has a branched structure. Furthermore, the average number of branched chains per molecule of the copolymer can be calculated from the peak intensity.

[0058] In the copolymer according to the embodiment, the crosslinked structure formed in the core of the copolymer can be decomposed by a hydration reaction or a transesterification reaction, and only the polymer corresponding to the arm structure of the copolymer can be recovered. Regarding the structure of the recovered polymer, unreacted vinyl groups in the crosslinked structure that existed in the core structure of the copolymer before the decomposition reaction can be identified by NMR measurement. When a copolymer has a main chain and branched chains in at least one block segment and is composed of the same structural units as the structural units of the main chain at the portion where the branching of the branched chain occurs, the copolymer can be similarly identified by carrying out a decomposition reaction of the copolymer and measuring the recovered polymer by NMR. Regarding the fact that the main chain and branched chains are composed of the same structural units, in addition to the above measurement results, the composition change during the polymerization process was also investigated. 1 This can be confirmed by tracing with H-NMR. These make it possible to confirm the structure of the copolymer according to the embodiment.

[0059] The presence of iodine atoms in the copolymer according to the embodiment can be confirmed by elemental analysis. Furthermore, the locations of the iodine atoms can be identified by measuring a section of the copolymer by X-ray photoelectron spectroscopy (XPS).

[0060] The Mn of the copolymer according to the embodiment is preferably 5,000 or more, more preferably 10,000 or more, and even more preferably 15,000 or more. The Mn of the copolymer is preferably 200,000 or less, more preferably 100,000 or less, and even more preferably 50,000 or less. The preferred lower and upper limits of the Mn of the copolymer can be arbitrarily combined. For example, 5,000 to 200,000 is preferred, 10,000 to 100,000 is more preferred, and 15,000 to 50,000 is more preferred. When the Mn of the copolymer is equal to or greater than the lower limit, the impregnation amount of the low-molecular-weight compound can be increased. When the Mn of the copolymer is equal to or less than the upper limit, a sufficient number of arm structures can be obtained to form a star polymer structure.

[0061] The Mw / Mn of the copolymer according to the embodiment is preferably 10 or less, more preferably 5 or less, and even more preferably 3 or less. When the Mw / Mn of the copolymer is equal to or less than the upper limit, a star polymer having a uniform arm structure and core structure can be obtained. The smaller the Mw / Mn of the copolymer, the better.

[0062] The average particle size of the copolymer is preferably 10 nm or more, more preferably 20 nm or more, and even more preferably 50 nm or more. The average particle size of the copolymer is preferably 1,000 nm or less, more preferably 500 nm or less, and even more preferably 300 nm or less. The preferred lower and upper limits of the average particle size of the copolymer can be arbitrarily combined. For example, 10 to 1,000 nm is preferred, 20 to 500 nm is more preferred, and 50 to 300 nm is even more preferred. When the average particle size of the copolymer is equal to or greater than the lower limit, the impregnation amount of the low-molecular-weight compound can be increased. When the average particle size of the copolymer is equal to or less than the upper limit, a material with excellent optical properties can be obtained when the star polymer is composited with other resins. The average particle size of the copolymer can be determined by dynamic light scattering (DLS).

[0063] The uses of the copolymer according to the embodiment are not particularly limited, and examples thereof include dispersants, resin additives, coating compositions, and polymers for lithography.

[0064] [Method of producing copolymer] (1) First embodiment The method for producing a copolymer according to the first embodiment includes the following steps (I-1) and (I-2). (I-1) A polymerizable composition (M11) containing a macromonomer (A), a vinyl monomer (B), and an organic iodine compound (D) is polymerized to obtain a macroinitiator consisting of a block copolymer. (I-2) Polymerizable composition (M22) containing the macroinitiator and vinyl monomer (C) is polymerized.

[0065] <Process (I-1)> In step (I-1), a polymerizable composition (M11) containing a macromonomer (A), a vinyl monomer (B), and an organic iodine compound (D) is polymerized to obtain a composition containing a block copolymer having a block segment composed of a structural unit derived from the macromonomer (A) and a block segment composed of a structural unit derived from the vinyl monomer (B), wherein the block segment composed of the structural unit derived from the vinyl monomer (B) has an iodine atom at the end of the main chain. The block copolymer functions as a macroinitiator in the polymerization in step (I-2). The macromonomer (A) and the vinyl monomer (B) are as described above.

[0066] (Organic iodine compounds (D)) In step (I-1), an organic iodine compound (D) (dormant species) having a carbon-iodine bond is added, and the iodine donated to the growing chain from the organic iodine compound (D) is used as a protecting group. The organic iodine compound (D) is not particularly limited as long as it has at least one carbon-iodine bond in the molecule and acts as a dormant species. The organic iodine compound (D) is preferably a compound containing one or two iodine atoms in one molecule. The organic iodine compound (D) may be added to the polymerizable composition as the organic iodine compound (D), or may be added as another compound and then reacted in the polymerizable composition to produce the organic iodine compound (D).

[0067] Examples of the organic iodine compound (D) include iodotrichloromethane, dichlorodiiodomethane, iodotribromomethane, dibromodiiodomethane, bromotriiodomethane, iodoform, diiodomethane, methyl iodide, triiodoethane, ethyl iodide, diiodopropane, isopropyl iodide, t-butyl iodide, iododichloroethane, chlorodiiodoethane, diiodopropane, chloroiodopropane, iododibromoethane, bromoiodopropane, 2-iodo-2-polyethylenediamine, 2-iodo-2-phenylpropane ... Ethylene glycosylpropane, 2-iodo-2-amidinopropane, 2-iodo-2-cyanobutane, 2-iodo-2-cyano-4-methylpentane, 2-iodo-2-cyano-4-methyl-4-methoxypentane, 4-iodo-4-cyanopentanoic acid, methyl-2-iodoisobutyrate, 2-iodo-2-methylpropanamide, 2-iodo-2,4-dimethylpentane, 2-iodo-2-cyanobutanol, 2-iodo-2-methyl-N-(2-hydroxyethyl)propionamido-4- Methylpentane, 2-iodo-2-methyl-N-(1,1-bis(hydroxymethyl)-2-hydroxyethyl)propionamido-4-methylpentane, 2-iodo-2-(2-imidazolin-2-yl)propane, 2-iodo-2-(2-(5-methyl-2-imidazolin-2-yl)propane, iodobenzyl cyanide (PhCN-I), ethyl-2-iodophenylacetate (EPh-I), diethyl-2-iodo-2-methylmalonate (EEMA-I), 2-iodo-2-cyanide Iodopropane (CP-I), 1-iodo-1-cyanoethane (CE-I), 1-iodo-1-phenylethane (PE-I), ethyl 2-iodoisobutyrate (EMA-I), ethyl 2-iodovalerate (EPA-I), ethyl 2-iodopropionate (EA-I), ethyl 2-iodoacetate (EI), 2-iodoisobutyric acid (MAA-I), hydroxyethyl 2-iodoisobutyrate (HEMA-I), 2-iodopropionic acid amide (AAm-I), ethylene glycol bis(2-iodoisobutyrate) (EMA-II), diethyl 2,Examples include 5-diiodoadipate (EA-II), glycerol-tris(2-iodoisobutyrate) (EMA-III), and 6-(2-iodo-2-isobutyloxy)hexyltriethoxysilane (IHE). The organic iodine compound (D) may be used alone or in combination of two or more kinds.

[0068] From the viewpoint of polymerization control, the organic iodine compound (D) is preferably at least one selected from the group consisting of PhCN-I, PhE-I, EEMA-I, CP-I, CE-I, PE-I, EMA-I, EPA-I, EA-I, EI, MAA-I, HEMA-I, AAm-I, EMA-II, EA-II, EMA-III, and IHE.

[0069] The polymerizable composition (M11) preferably further contains either or both of a catalyst (E) and an azo-based radical polymerization initiator (F), since this makes it easier to improve the polymerization rate and the monomer conversion rate.

[0070] (Catalyst (E)) The catalyst (E) is used to abstract the iodine atom from the carbon atom-iodine atom bond. The addition of the catalyst (E) promotes the homolytic dissociation reaction of the iodine atom from the carbon atom-iodine atom bond, thereby increasing the polymerization rate. The catalyst (E) includes not only the catalyst itself but also a precursor that generates a catalyst during the polymerization reaction when added to the polymerizable composition.

[0071] The catalyst (E) is preferably at least one selected from the group consisting of the following catalysts (E1) to (E6). Catalyst (E1): A non-metallic compound containing a halide ion and a non-metallic atom in a cationic state that forms an ionic bond with the halide ion. Catalyst (E2): A compound containing a carbon atom and at least one halogen atom directly bonded to the carbon atom (hereinafter also referred to as "compound (E21)"), or a hydrocarbon compound that serves as a precursor of compound (E21). Catalyst (E3): An organic compound having a nitrogen atom, a phosphorus atom, a sulfur atom, or an oxygen atom and having oxidation-reduction properties. Catalyst (E4): A compound selected from the group consisting of ethylene, acetylene, oligoacetylene, polyacetylene, fullerene, carbon nanotube, and derivatives thereof. Catalyst (E5): an alkali metal halide compound or an alkaline earth metal halide compound. Catalyst (E6): A compound selected from the group consisting of phosphorus compounds, nitrogen-containing compounds, and oxygen-containing compounds other than the catalysts (E1) to (E5).

[0072] Examples of the catalyst (E1) include the following compounds. Examples of non-metallic compounds having a nitrogen atom as a non-metallic atom include imidazole salt compounds, pyridine salt compounds, quaternary amine salt compounds, and derivatives thereof.

[0073] Examples of the imidazole salt compound include 1-methyl-3-methyl-imidazolium iodide (EMIZI) and 1-ethyl-3-methylimidazolium bromide (EMIZBr). An example of the pyridine salt compound is 2-chloro-1-methylpyridinium iodide (CMPI). Examples of the quaternary amine salt compound include tetra-n-butylammonium iodide (BNI), tetra-n-butylammonium triiodide (BNI3), and tetra-n-butylammonium bromodiiodide (BNBrI2).

[0074] Examples of non-metallic compounds having a phosphorus atom as a non-metallic atom include phosphonium salt compounds such as methyltributylphosphonium iodide (BMPI), tetraphenylphosphonium iodide (PPI), and derivatives thereof. Examples of non-metallic compounds having a sulfur atom as a non-metallic atom include tributylsulfonium iodide (BSI) and its derivatives. An example of a non-metallic compound having an iodine atom as a non-metallic atom is diphenyliodonium iodide (PII). Examples of non-metallic compounds having two types of non-metallic atoms include hexaphenyldiphosphazenium chloride (PPNCl) and its derivatives.

[0075] Examples of the catalyst (E2) include the following compounds. Examples of the compound (E21) include carbon halides (CI4, etc.), alkyl halides ((CH3)3CI, (CH3)2CI2, CH3CI3, etc.), aryl halides (diphenylmethane iodide, etc.), and heteroaryl halides.

[0076] Examples of hydrocarbon compounds that serve as precursors of the compound (E21) include compounds in which the halogen atoms bonded to the carbon atoms in the compound (E21) are substituted with hydrogen atoms. For example, a compound in which one or two hydrogen atoms and two or three radical-stabilizing substituents are bonded to a carbon atom is preferred. The radical-stabilizing substituent is preferably a substituent that forms a resonance structure with the carbon atom of the central element. The carbon atom of the central element may be bonded to one substituent other than the hydrogen atom and the radical-stabilizing substituent, but it is preferred that no other substituents are bonded to the carbon atom of the central element.

[0077] Examples of the catalyst (E3) include organic compounds having a nitrogen atom, a phosphorus atom, a sulfur atom, and an oxygen atom and having redox properties. Examples of organic compounds having a nitrogen atom include trialkylamines (triethylamine, tributylamine, etc.), tetrakisdimethylaminoethene (TDAE), and 1,4,8,11-tetramethyl-1,4,8,11-tetraazacyclotetradecane tributylphosphine (TDME). Organic compounds having hole transport ability may also be used. In addition, phthalimides, pyridines, bipyridines, N,N,N',N",N"-pentamethyldiethylenetriamine (PMDETA), ethylenediamine, dimethylethylenediamine, tetramethylethylenediamine, tetramethyldiaminomethane, tris(2-aminoethyl)amine, tris(2-(methylamino)ethyl)amine, hematoporphyrin, and derivatives thereof may also be used.

[0078] Examples of organic compounds having a phosphorus atom include trialkylphosphines (such as triethylphosphine), triarylphosphines (such as triphenylphosphine), phosphonic acid, 1,2-bis(diphenylphosphino)methane, and derivatives thereof.

[0079] Examples of organic compounds having a sulfur atom include thiophene, oligothiophene, polythiophene, tetrathiofulvalene (TTF), bis(ethylenedithio)tetrathiafulvalene (BTTF), 3,4-ethylenedioxythiophene (EDOT), poly(3,4-ethylenedioxythiophene (PEDOT)), and derivatives thereof.

[0080] Examples of organic compounds having an oxygen atom include furan, oligofuran, polyfuran, and derivatives thereof.

[0081] The catalyst (E4) is a compound having a carbon atom as a central element, such as ethylene, acetylene, oligoacetylene, polyacetylene, fullerene, or carbon nanotube, or a derivative thereof.

[0082] Examples of the alkali metal atom of the alkali metal halide compound in the catalyst (E5) include lithium, sodium, potassium, rubidium, cesium, and francium. Examples of the alkaline earth metal atom of the alkaline earth metal halide compound include beryllium, magnesium, calcium, strontium, barium, and radium. Among these, sodium, potassium, cesium, magnesium, and calcium are preferred, and sodium and potassium are particularly preferred. Examples of halogen atoms contained in the alkali metal halide compound and alkaline earth metal halide compound include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom. Among these, a bromine atom or an iodine atom is preferred, and an iodine atom is particularly preferred, in terms of facilitating narrowing of the molecular weight distribution.

[0083] Examples of the alkali metal halide compound include sodium iodide, potassium iodide, and cesium iodide. Examples of the alkaline earth metal halide compound include magnesium iodide and calcium iodide.

[0084] Examples of the catalyst (E6) include the following compounds. Examples of phosphorus compounds include phosphite esters and phosphinate compounds. Examples of phosphite esters include dimethyl phosphite, diethyl phosphite, dibutyl phosphite, diphenyl phosphite, dibenzyl phosphite, bis(2-ethylhexyl) phosphite, bis(2,2,2-trifluoroethyl) phosphite, diallyl phosphite, and ethylene phosphite. Examples of the phosphinate compound include diperfluoroethyl phosphinate, ethoxyphenyl phosphinate, phenylphenoxy phosphinate, ethoxymethyl phosphinate, and phenoxymethyl phosphinate. As the phosphorus compound, dimethyl phosphite, diethyl phosphite, dibutyl phosphite, and diphenyl phosphite are preferred from the viewpoints of availability and solubility. These phosphorus compounds may be used alone or in combination of two or more.

[0085] Examples of the nitrogen-containing compound include imide compounds. Examples of imide compounds include succinimide, 2,2-dimethylsuccinimide, α,α-dimethyl-β-methylsuccinimide, 3-ethyl-3-methyl-2,5-pyrrolidinedione, cis-1,2,3,6-tetrahydrophthalimide, α-methyl-α-propylsuccinimide, 5-methylhexahydroisoindole-1,3-dione, 2-phenylsuccinimide, α-methyl-α-phenylsuccinimide, 2,3-diacetoxysuccinimide, maleimide, phthalimide, 4-methylphthalimide, N-chlorophthalimide, N-bromophthalimide, 4-nitrophthalimide, 2,3-naphthalenecarboximide, pyromelliticdiimide, 5-bromoisoindole-1,3-dione, N-chlorosuccinimide, N-bromosuccinimide, and N-iodosuccinimide (NIS). As the nitrogen-containing compound, succinimide, phthalimide, N-chlorosuccinimide, N-bromosuccinimide, and NIS are preferred from the viewpoints of availability and solubility. These nitrogen-containing compounds may be used alone or in combination of two or more.

[0086] Examples of oxygen-containing compounds include phenolic compounds having a phenolic hydroxyl group, iodooxyphenyl compounds which are iodides of phenolic hydroxyl groups, and vitamins. Examples of phenolic compounds include phenol, hydroquinone, methoxyhydroquinone, t-butylphenol, t-butylmethylphenol, catechol, resorcinol, di-t-butylhydroxytoluene, dimethylphenol, trimethylphenol, and di-t-butyl group-bearing polymer fine particles. These can also be used as polymerization inhibitors for storage. An example of the iodoxyphenyl compound is thymol iodide. Examples of vitamins include vitamin C and vitamin E.

[0087] As the oxygen-containing compound, from the viewpoints of availability and solubility, phenol, catechol, vitamin C, and vitamin E are preferred. These oxygen-containing compounds may be used alone or in combination of two or more.

[0088] (Azo-based radical polymerization initiator (F)) The azo radical polymerization initiator (F) is used for the purpose of increasing the radical concentration in the polymerizable composition (M11) and increasing the polymerization rate when polymerizing the polymerizable composition containing the macromonomer (A), the vinyl monomer (B), and the organic iodine compound (D).

[0089] Examples of the azo radical polymerization initiator (F) include 2,2'-azobis(isobutyronitrile), 2,2'-azobis(2-methylbutyronitrile), 2,2'-azobis(2,4-dimethylvaleronitrile), 1,1'-azobis(cyclohexane-1-carbonitrile), and 2,2'-azobis(2,4-dimethyl-4-methoxyvaleronitrile). The azo radical polymerization initiator (F) may be used alone or in combination of two or more kinds.

[0090] Among the azo radical polymerization initiators (F), 2,2'-azobis(isobutyronitrile) (10-hour half-life temperature 65°C), 2,2'-azobis(2-methylbutyronitrile) (10-hour half-life temperature 67°C), 2,2'-azobis(2,4-dimethylvaleronitrile) (10-hour half-life temperature 51°C), and 1,1'-azobis(cyclohexane-1-carbonitrile) (10-hour half-life temperature 88°C) are preferred. This is because the 10-hour half-life temperatures of these azo radical polymerization initiators are in an appropriate range, making it easy to control polymerization.

[0091] (solvent) A solvent can be added to the polymerizable composition (M11) as needed. Examples of the solvent include the same solvents as those mentioned in the polymerization for obtaining the macromonomer (A).

[0092] Other additives may be added to the polymerizable composition (M11) as needed, such as a chain transfer agent such as mercaptan.

[0093] (Composition of polymerizable composition (M11)) The composition of the polymerizable composition (M11) will be explained below. Hereinafter, the term "amount used" refers to the amount charged into the polymerizable composition. The amount of macromonomer (A) used is preferably more than 15% by mass, more preferably more than 30% by mass, based on the total amount of macromonomer (A) and vinyl monomer (B) in terms of charge ratio (mass ratio). It is also preferably less than 85% by mass, more preferably less than 70% by mass. The preferred lower and upper limits of the amount of macromonomer (A) used can be arbitrarily combined. For example, more than 15% by mass and less than 85% by mass is preferred, and more preferably more than 30% by mass and less than 70% by mass. When the amount of macromonomer (A) used is within the above range, the physical properties expected to be imparted to the copolymer by macromonomer (A) are more easily reflected in the copolymer.

[0094] The amount of vinyl monomer (B) used is preferably more than 15% by mass, more preferably more than 30% by mass, based on the total amount of macromonomer (A) and vinyl monomer (B) in terms of charge ratio (mass ratio). It is also preferably less than 85% by mass, more preferably less than 70% by mass. The preferred lower and upper limits of the amount of vinyl monomer (B) used can be arbitrarily combined. For example, more than 15% by mass and less than 85% by mass is preferred, and more preferably more than 30% by mass and less than 70% by mass. When the amount of vinyl monomer (B) used is within the above range, the physical properties expected to be imparted to the copolymer by the vinyl monomer (B) are more easily reflected in the copolymer.

[0095] The amount of the organic iodine compound (D) used is preferably 0.001 mol or more, more preferably 0.002 mol or more, and preferably 0.5 mol or less, more preferably 0.1 mol, per mol of the vinyl monomer (B). The preferred lower and upper limits of the amount of the organic iodine compound (D) used can be arbitrarily combined. For example, 0.001 to 0.5 mol is preferred, and 0.002 to 0.1 mol is more preferred. When the amount of the organic iodine compound (D) used is within the above range, it is sufficient to provide iodine as a protecting group to the growing chain, and does not excessively reduce the polymerization rate.

[0096] When catalyst (E) is used, the amount of catalyst (E) used is preferably 0.1 mmol / L or more, more preferably 0.5 mmol / L or more, and preferably 1000 mmol / L or less, more preferably 500 mmol / L or less, relative to 1 L of reaction solution. The preferred lower and upper limits of the amount of catalyst (E) used can be arbitrarily combined. For example, 0.1 to 1000 mmol / L is preferred, and 0.5 to 500 mmol / L is more preferred. When the amount of catalyst (E) used is within the above range, the polymerization rate is sufficiently promoted and the molecular weight distribution can be narrowed.

[0097] When an azo radical polymerization initiator (F) is used, the amount of the azo radical polymerization initiator (F) used is, in terms of molar equivalents relative to the organic iodine compound (D), preferably more than 0.001 equivalents, more preferably more than 0.002 equivalents, and preferably not more than 10 equivalents, more preferably not more than 5 equivalents. The preferred lower and upper limits of the amount of the azo radical polymerization initiator (F) used can be arbitrarily combined. For example, more than 0.001 equivalents and not more than 10 equivalents are preferred, and more preferably more than 0.002 equivalents and not more than 5 equivalents. When the amount of the azo radical polymerization initiator (F) used is equal to or greater than the lower limit, an appropriate polymerization rate can be obtained. When the amount of the azo radical polymerization initiator (F) used is equal to or less than the upper limit, the amount of homopolymer of the vinyl monomer (B) produced as a by-product can be reduced.

[0098] When a solvent is used, the amount of the solvent used is preferably 30 parts by mass or more and 700 parts by mass or less per 100 parts by mass of the vinyl monomer (B).

[0099] (Polymerization conditions) The polymerization method for the polymerizable composition (M11) is not particularly limited, and examples thereof include bulk polymerization, solution polymerization, suspension polymerization, and emulsion polymerization. The polymerization reaction may be carried out in the presence of air, but from the viewpoint of the efficiency of radical polymerization, it is preferable to carry out the reaction under conditions in which the air is replaced with an inert gas such as nitrogen or argon.

[0100] The polymerization temperature is preferably 0 to 150°C in terms of the polymerization rate, etc., and more preferably 20 to 120°C in terms of polymerization control. The polymerization temperature is preferably maintained constant until the conversion of the vinyl monomer (B) reaches 60%, since this facilitates the polymerization to proceed to a region where the monomer conversion rate is high. The temperature condition after the monomer conversion rate exceeds 60% is not limited to a constant value, and for example, the temperature can be further increased.

[0101] From the viewpoint of controlling the polymerization, it is preferable that the polymerization temperature satisfies the following formula (1). 0 <T p -T 10 <40 (1) However, T p is the polymerization temperature (℃), and T 10 is the 10-hour half-life temperature (°C) of the azo radical polymerization initiator (F). The 10-hour half-life temperature is a value specific to the structure of the radical polymerization initiator. T p -T 10 By setting T in the above range, the polymerization rate can be maintained, the monomer conversion rate can be increased, and the polymerization can be easily controlled. When the polymerizable composition (M11) does not contain the catalyst (E), the polymerization control becomes more necessary. p -T 10 is preferably within the above range.

[0102] The polymerization time is not particularly limited and can be, for example, 0.5 to 24 hours.

[0103] The specific polymerization mechanism of step (I-1) will be explained using a polymerizable composition (M1) containing a macromonomer (A) having a structural unit derived from methyl methacrylate (hereinafter also referred to as "MMA"), n-butyl acrylate (hereinafter also referred to as "BA") as the vinyl monomer (B), 2-iodo-2-cyanopropane (hereinafter also referred to as "CP-I") as the organic iodine compound (D), and tetra-n-butylammonium iodide (hereinafter also referred to as "BNI") as the catalyst (E). The polymerization in this example is thought to proceed as follows (1) to (4).

[0104] (1) As shown in the following formula (1), first, a carbon radical is generated from the organic iodine compound (C), CP-I, by the action of the catalyst (E), BNI. The generated carbon radical reacts with the vinyl monomer (B), BA, to form a propagating radical having a structural unit derived from BA. (2) As shown in the following formula (2), when the propagating radical reacts with the macromonomer (A), an addition-fragmentation chain transfer occurs, producing a macromonomer (B') having a structural unit derived from BA and a propagating radical (A') derived from the macromonomer (A) in the system. (3) As shown in the following formula (3), the growing radical (A') combines with iodine to generate a dormant species. (4) As shown in the following formula (4), dormant species repeatedly generate propagating radicals under the action of catalyst (E). The reaction between these propagating radicals and BA progresses, resulting in the growth of a block copolymer (PMMA-PBA-I).

[0105] [ka]

[0106] According to the mechanism described above, macromonomer (A) is consumed in the early stages of polymerization, and a block copolymer is produced in which a block derived from macromonomer (A) is combined with a block derived from vinyl monomer (B), BA. In addition, macromonomer (B') containing structural units derived from BA is produced. Furthermore, the polymerization proceeds in a controlled manner due to the presence of terminal iodine. In addition to reacting with BA, the propagating radical (A') can also react with macromonomer (B') having BA-derived structural units. As a result, a branched chain is introduced into the BA-derived block, and the macromonomer (B') having BA-derived structural units produced in the system is consumed.

[0107] <Process (I-2)> In step (I-2), the polymerizable composition (M21) containing the macroinitiator obtained in step (I-1) and the vinyl monomer (C) is polymerized to obtain the copolymer according to the embodiment. The vinyl monomer (C) is as described above.

[0108] In method (I), the composition obtained in step (I-1) may be purified to recover the macroinitiator, and then a vinyl monomer (C) may be added to the macroinitiator to form a polymerizable composition (M21) (two-pot synthesis), or the composition obtained in step (I-1) may be directly added with a vinyl monomer (C1) without being purified to form a polymerizable composition (M21) (one-pot synthesis). Note that a vinyl monomer (C2) may be added to the composition obtained in step (I-1) in addition to the vinyl monomer (C1). In step (I-2), the proportion of the vinyl monomer (C1) having two or more vinyl groups in the molecule relative to the total amount of the vinyl monomer (C) is 10 mol% or more, preferably 20 mol% or more, more preferably 30 mol% or more, even more preferably 50 mol% or more, and particularly preferably 80 mol% or more. If the proportion of the vinyl monomer (C1) is equal to or greater than the lower limit, the molecular weight of the copolymer increases. The upper limit of the proportion of the vinyl monomer (C1) can be 100 mol%.

[0109] FIG. 1 is an explanatory diagram showing a schematic example of a one-pot synthesis in which the composition obtained in step (I-1) is purified, and a two-pot synthesis in which the composition is not purified, using PMMA-Y (where Y represents —CHCH(═CH)-COOCH) as the macromonomer (A), BA as the vinyl monomer (B), and diethylene glycol diacrylate (DGDA) as the vinyl monomer (C1).

[0110] As shown in Route 1 in Figure 1, in the case of a two-pot synthesis in which the composition obtained in step (I-1) is purified, the unreacted BA in step (I-1) is separated and removed, and is therefore not substantially contained in the polymerizable composition (M21). On the other hand, as shown in Route 2 in Figure 1, in the case of a one-pot synthesis in which the composition obtained in step (I-1) is not purified, the polymerizable composition (M21) contains the unreacted BA in step (I-1). Typically, the polymerizable composition (M21) obtained by one-pot synthesis contains BA, a non-crosslinkable monomer having only one vinyl group in the molecule. Therefore, the core structure of the copolymer obtained by one-pot synthesis is larger in size and has a lower crosslink density than that of the copolymer obtained by two-pot synthesis.

[0111] The method for purifying the composition obtained in step (I-1) may be any method that can recover the macroinitiator, and examples thereof include reprecipitation, liquid-liquid phase separation, dialysis, etc. As a purification method, reprecipitation is preferred because it can be applied to a wide variety of polymers and can efficiently remove impurities by using an appropriate combination of solvents.

[0112] (Catalyst (G)) The polymerizable composition (M21) preferably further contains a catalyst (G). The catalyst (G) is used for the purpose of abstracting the iodine atom from the carbon atom-iodine atom bond at the end of the main chain of the block copolymer, which is the macroinitiator obtained in step (I-1). When the polymerizable composition (M21) contains the catalyst (G), the homolytic dissociation reaction of the iodine atom from the carbon atom-iodine atom bond is promoted, thereby increasing the polymerization rate.

[0113] The catalyst (G) is preferably at least one selected from a compound having a nitrogen-containing functional group and an iodide salt. The "compound having a nitrogen-containing functional group" also includes a polymer compound having a nitrogen-containing functional group.

[0114] Examples of compounds having a nitrogen-containing functional group include trialkylamines (triethylamine, tributylamine, etc.), tetrakisdimethylaminoethene (TDAE), 1,4,8,11-tetramethyl-1,4,8,11-tetraazacyclotetradecanetributylphosphine (TDME), phthalimides, pyridines, bipyridines, N,N,N',N",N"-pentamethyldiethylenetriamine (PMDETA), ethylenediamine, dimethylethylenediamine, tetramethylethylenediamine, tetramethyldiaminomethane, tris(2-aminoethyl)amine, tris(2-(methylamino)ethyl)amine, hematoporphyrin, and derivatives thereof; succinimide, 2,2-dimethylsuccinimide, α,α -dimethyl-β-methylsuccinimide, 3-ethyl-3-methyl-2,5-pyrrolidinedione, cis-1,2,3,6-tetrahydrophthalimide, α-methyl-α-propylsuccinimide, 5-methylhexahydroisoindole-1,3-dione, 2-phenylsuccinimide, α-methyl-α-phenylsuccinimide, 2,3-diacetoxysuccinimide, maleimide, phthalimide, 4-methylphthalimide, N-chlorophthalimide, N-bromophthalimide, 4-nitrophthalimide, 2,3-naphthalenecarboximide, pyromellidiimide, 5-bromoisoindole-1,3-dione, N-chlorosuccinimide, N-bromosuccinimide, and N-iodosuccinimide (NIS). In terms of availability and solubility, triethylamine, tributylamine, TDAE, TDME, PMDETA, succinimide, phthalimide, N-chlorosuccinimide, N-bromosuccinimide, and NIS are preferred. The compound having a nitrogen-containing functional group may be used alone or in combination of two or more kinds.

[0115] Examples of iodide salts include imidazole salt compounds such as 1-methyl-3-methyl-imidazolium iodide (EMIZI) and 1-ethyl-3-methylimidazolium bromide (EMIZBr); pyridine salt compounds such as 2-chloro-1-methylpyridinium iodide (CMPI); quaternary amine salt compounds such as tetra-n-butylammonium iodide (BNI), tetra-n-butylammonium triiodide (BNI3), tetra-n-butylammonium bromodiiodide (BNBrI2), and tetra-n-octylammonium iodide (ONI); and methyltributylphosphonium Examples of suitable iodide compounds include phosphonium salt compounds such as tetraphenylphosphonium iodide (BMPI), tetraphenylphosphonium iodide (PPI) and its derivatives, tributylsulfonium iodide (BSI) and its derivatives, diphenyliodonium iodide (PII), hexaphenyldiphosphazenium chloride (PPNCl) and its derivatives, alkali metal iodide compounds such as sodium iodide, potassium iodide, and cesium iodide, and alkaline earth metal iodide compounds such as magnesium iodide and calcium iodide. In terms of availability, BNI, ONI, BNPI, sodium iodide, and potassium iodide are preferred. The iodide salts may be used alone or in combination of two or more.

[0116] The catalyst (G) may contain a radical polymerization initiator, which increases the polymerization rate of the copolymer. As the radical polymerization initiator, for example, an organic peroxide or an azo compound can be used.

[0117] Examples of organic peroxides include 2,4-dichlorobenzoyl peroxide, t-butyl peroxypivalate, o-methylbenzoyl peroxide, bis-3,5,5-trimethylhexanoyl peroxide, octanoyl peroxide, t-butylperoxy-2-ethylhexanoate, cyclohexanone peroxide, benzoyl peroxide, methyl ethyl ketone peroxide, dicumyl peroxide, lauroyl peroxide, diisopropylbenzene hydroperoxide, t-butyl hydroperoxide, and di-t-butyl peroxide.

[0118] Examples of azo compounds include 2,2'-azobisisobutyronitrile, 2,2'-azobis(2,4-dimethylvaleronitrile), and 2,2'-azobis(2,4-dimethyl-4-methoxyvaleronitrile).

[0119] The radical polymerization initiator is preferably benzoyl peroxide, 2,2'-azobisisobutyronitrile, 2,2'-azobis(2,4-dimethylvaleronitrile), or 2,2'-azobis(2,4-dimethyl-4-methoxyvaleronitrile). The radical polymerization initiator may be used alone or in combination of two or more kinds.

[0120] The amount of vinyl monomer (C) used is preferably 10 parts by mass or more, more preferably 20 parts by mass or more, and even more preferably 30 parts by mass or more, relative to 100 parts by mass of the block copolymer serving as a macroinitiator, and is preferably 100 parts by mass or less, more preferably 90 parts by mass or less, and even more preferably 80 parts by mass or less. The preferred lower and upper limits of the amount of vinyl monomer (C) used can be arbitrarily combined, and are, for example, preferably 10 to 100 parts by mass, more preferably 20 to 90 parts by mass, and even more preferably 30 to 80 parts by mass.

[0121] The amount of catalyst (G) used, relative to 1 L of polymerizable composition (M21), is preferably 0.1 mmol / L or more, more preferably 0.5 mmol / L or more, and is preferably 2000 mmol / L or less, more preferably 1500 mmol / L or less. The preferred lower and upper limits of the amount of catalyst (G) used can be arbitrarily combined, and are, for example, preferably 0.1 to 2000 mmol / L, more preferably 0.5 to 1500 mmol / L. When the amount of catalyst (G) used is within the above range, the polymerization rate of the copolymer is sufficiently improved, and a copolymer with a narrow molecular weight distribution can be obtained.

[0122] When the catalyst (G) contains a radical polymerization initiator, the amount of the radical polymerization initiator used in the polymerizable composition (M21) is preferably 0.001 mol or more, more preferably 0.002 mol or more, and preferably 0.05 mol or less, more preferably 0.02 mol or less, per mol of the block copolymer as the macroinitiator. The preferred lower and upper limits of the amount of the radical polymerization initiator used can be arbitrarily combined, and are, for example, preferably 0.001 to 0.05 mol, more preferably 0.002 to 0.02 mol.

[0123] (solvent) A solvent can be added to the polymerizable composition (M21) as needed. Examples of the solvent include the same solvents as those mentioned in the polymerization for obtaining the macromonomer (A). The amount of the solvent used in the polymerizable composition (M21) is preferably 20 to 90% by mass based on the total amount of the polymerizable composition (M21).

[0124] (Other additives) Other additives may be added to the polymerizable composition (M21). Other additives include, for example, chain transfer agents such as mercaptans and iodine.

[0125] (Polymerization conditions) The method for polymerizing the polymerizable composition (M21) is not particularly limited, and examples thereof include bulk polymerization, solution polymerization, suspension polymerization, and emulsion polymerization. The polymerization of the polymerizable composition (M21) may be carried out in the presence of air, but from the viewpoint of polymerization efficiency, it is preferably carried out under conditions in which the air is replaced with an inert gas such as nitrogen or argon.

[0126] The polymerization temperature of the polymerizable composition (M21), i.e., the temperature of the polymerizable composition (M21) during polymerization, is preferably 0° C. or higher, more preferably 20° C. or higher, and is preferably 150° C. or lower, more preferably 120° C. or lower, from the viewpoint of polymerization rate and polymerization control. The lower and upper limits of the temperature of the polymerizable composition (M21) during polymerization can be arbitrarily combined, and are, for example, preferably 0 to 150° C., more preferably 20 to 120° C. The temperature of the polymerizable composition (M21) during polymerization is preferably maintained constant from the start of polymerization until the conversion rate of the vinyl monomer (C) reaches 50%. This facilitates the polymerization to proceed to a region where the conversion rate of the vinyl monomer (C) is high. The temperature after the conversion rate of the vinyl monomer (C) exceeds 50% is not particularly limited, and the temperature may be further increased.

[0127] The polymerization time of the polymerizable composition (M21) is not particularly limited, but is preferably from 0.5 to 72 hours, more preferably from 0.5 to 60 hours.

[0128] (2) Second embodiment The method for producing a copolymer according to the second embodiment includes the following steps (II-1) and (II-2). (II-1) A polymerizable composition (M12) containing a macromonomer (A), a vinyl monomer (B), an azo-based radical polymerization initiator (F) and iodine is polymerized to obtain a macroinitiator consisting of a block copolymer. (II-2) Polymerizable composition (M22) containing the macroinitiator and vinyl monomer (C) is polymerized.

[0129] <Process (II-1)> In step (II-1), a polymerizable composition (M12) containing a macromonomer (A), a vinyl monomer (B), an azo-based radical polymerization initiator (F), and iodine is polymerized. As a result, similar to step (I-1) described above, a composition containing a block copolymer having a block segment composed of a structural unit derived from the macromonomer (A) and a block segment composed of a structural unit derived from the vinyl monomer (B), and having an iodine atom at the main chain terminal of the block segment composed of the structural unit derived from the vinyl monomer (B) is obtained. The block copolymer functions as a macroinitiator in the polymerization in step (II-2). The macromonomer (A), the vinyl monomer (B) and the azo-based radical polymerization initiator (F) are as described above.

[0130] In step (II-1), during the polymerization of the polymerizable composition (M12), at least a portion of the azo radical polymerization initiator (F) and iodine react with each other to produce an organic iodine compound (D) in the polymerizable composition (M12), which functions as a dormant species. The polymerizable composition (M12) preferably further contains a catalyst (E) because this facilitates improving the polymerization rate and the monomer conversion. The catalyst (E) is as described above.

[0131] (solvent) A solvent can be added to the polymerizable composition (M12) as needed. Examples of the solvent include the same solvents as those mentioned in the polymerization for obtaining the macromonomer (A).

[0132] (Composition of polymerizable composition (M12)) The preferred ranges of the amount of the macromonomer (A), the amount of the vinyl monomer (B), and the amount of the azo radical polymerization initiator (F) used in the polymerizable composition (M12) are the same as those in the polymer composition (M11).

[0133] The amount of iodine used preferably satisfies the following formula (2). 0<[Q] / [P]<0.60 (2) Here, [Q] is the number of molar equivalents of iodine in the polymerizable composition (M12), and [P] is the number of molar equivalents of the azo-based radical polymerization initiator (F).

[0134] [Q] / [P] is preferably 0.01 or more, more preferably 0.1 or more. When [Q] / [P] is equal to or greater than the lower limit, the molecular weight and molecular weight distribution are adequately controlled. When [Q] / [P] is less than 0.60, it is easy to prevent polymerization from being inhibited by side reactions. The initiator efficiency of the azo radical polymerization initiator (F) is generally about 0.6 to 0.7. Therefore, it is most preferable that the amount of iodine used satisfies 0.1≦[Q] / [P]<0.60. When the polymerizable composition (M12) contains the catalyst (E), it is also preferable to set [Q] / [P] within the above range. However, when the polymerizable composition (M12) does not contain the catalyst (E), polymerization control becomes more necessary, and therefore it is particularly preferable to set [Q] / [P] within the above range.

[0135] When the catalyst (E) is used in the polymerizable composition (M12), the amount of the catalyst (E) used is the same as in the case of the polymer composition (M11). When a solvent is used in the polymerizable composition (M12), the amount of the solvent used is the same as in the case of the polymer composition (M11).

[0136] (Polymerization conditions) As with the polymerizable composition (M11), the polymerization conditions for the polymerizable composition (M12) can be bulk polymerization, solution polymerization, suspension polymerization, emulsion polymerization, etc. The polymerization reaction of the polymerizable composition (M12) may be carried out in the presence of air, but from the viewpoint of the efficiency of radical polymerization, it is preferable to carry out the reaction under conditions in which the air is replaced with an inert gas such as nitrogen or argon. The preferred ranges of the polymerization temperature and polymerization time are also the same as those for the polymerizable composition (M11).

[0137] <Process (II-2)> In the step (II-2), the polymerizable composition (M22) containing the macroinitiator obtained in the step (II-1) and the vinyl monomer (C) is polymerized. In the method (II), as in the method (I), the composition obtained in step (II-1) may be purified to recover the macroinitiator, and then the vinyl monomer (C) may be added to the macroinitiator to form the polymerizable composition (M22). Alternatively, the composition obtained in step (II-1) may be directly added with the vinyl monomer (C1) to form the polymerizable composition (M22) without purifying the composition obtained in step (II-1). Note that the vinyl monomer (C2) may be added to the composition obtained in step (II-1) in addition to the vinyl monomer (C1). In step (II-2), the proportion of the vinyl monomer (C1) having two or more vinyl groups in the molecule relative to the total amount of vinyl monomer (C) is 10 mol% or more, preferably 20 mol% or more, more preferably 30 mol% or more, even more preferably 50 mol% or more, and particularly preferably 80 mol% or more. If the proportion of the vinyl monomer (C1) is equal to or greater than the lower limit, the molecular weight of the copolymer increases. The upper limit of the proportion of the vinyl monomer (C1) can be 100 mol%.

[0138] In the case of a two-pot synthesis in which the composition obtained in step (I1-1) is purified, the unreacted vinyl monomer (B) in step (I1-1) is separated and removed, and is therefore not substantially contained in the polymerizable composition (M22). On the other hand, in the case of a one-pot synthesis in which the composition obtained in step (I1-1) is not purified, the polymerizable composition (M22) contains the unreacted vinyl monomer (B) in step (II-1), and this unreacted vinyl monomer (B) can be considered as the vinyl monomer (C2) in the polymerizable composition (M22). Typically, the polymerizable composition (M22) in the one-pot synthesis contains a vinyl monomer (C2), which is a non-crosslinkable monomer having only one vinyl group in the molecule. Therefore, the core structure of the copolymer obtained by the one-pot synthesis is larger in size and has a lower crosslink density than the copolymer obtained by the two-pot synthesis.

[0139] The method for purifying the composition obtained in step (II-1) can be the same as the method described in method (I), and the preferred embodiments are also the same.

[0140] Step (II-2) can be carried out in the same manner as step (I-2) described above, except that the composition obtained in step (II-1) is used with or without purification, and the preferred embodiments are also the same.

[0141] [Low molecular weight compound impregnated particles] The low-molecular-weight compound-impregnated particles according to the embodiment are particles obtained by impregnating the copolymer according to the embodiment with a low-molecular-weight compound having a molecular weight of 1000 or less. For example, by blending the low-molecular-weight compound-impregnated particles according to the embodiment with a matrix resin to form a resin composition, it is possible to prevent the low-molecular-weight compound from bleeding out from the resin composition, and to stably exert the effects of the low-molecular-weight compound.

[0142] The low-molecular-weight compound impregnated into the low-molecular-weight compound-impregnated particles is not particularly limited, and examples thereof include ultraviolet absorbers (UVA), light stabilizers (HALS), antioxidants, flame retardants, antistatic agents, etc. The low-molecular-weight compounds may be used alone or in combination of two or more.

[0143] The content of the low-molecular-weight compound in the low-molecular-weight compound-impregnated particles according to the embodiment is preferably 5% by mass or more, more preferably 10% by mass or more, and even more preferably 20% by mass or more. The content of the low-molecular-weight compound is preferably 90% by mass or less, more preferably 80% by mass or less, and even more preferably 70% by mass or less. The preferred lower and upper limits of the content of the low-molecular-weight compound can be arbitrarily combined. For example, 5 to 90% by mass is preferred, 10 to 80% by mass is more preferred, and 20 to 70% by mass is more preferred. When the content of the low-molecular-weight compound is equal to or greater than the lower limit, the effect of the low-molecular-weight compound is easily exhibited. When the content of the low-molecular-weight compound is equal to or less than the upper limit, the effect of suppressing bleed-out can be obtained.

[0144] The method for impregnating the copolymer according to the embodiment with the low-molecular-weight compound is not particularly limited, and examples thereof include a method in which the copolymer according to the embodiment is dissolved in a solvent to prepare a copolymer solution, and then the low-molecular-weight compound is added to the copolymer solution until it reaches a saturated state, followed by stirring. [Example]

[0145] The present invention will be specifically described below with reference to examples, but the present invention is not limited to the following descriptions.

[0146] [Number average molecular weight (Mn) and molecular weight distribution (Mw / Mn)] The number average molecular weight (Mn) and molecular weight distribution (Mw / Mn) of the macromonomer, block copolymer (macroinitiator), and copolymer were measured using a GPC (Tosoh Corporation, "HLC-8220"), and Mn and Mw / Mn were calculated from the PMMA calibration curve. The measurement conditions were as follows: (Measurement conditions) Column: TSK GUARD COLUMN SUPER HZ-L (4.6 mm x 35 mm) and TSK-GEL SUPER HZM-N (6.0 mm x 150 mm) connected in series Eluent: tetrahydrofuran Measurement temperature: 40℃ Flow rate: 0.6mL / min

[0147] [Monomer conversion rate] The monomer conversion rate (%) for each example is: 1 The yield was calculated as the ratio of the amount of polymer produced to the total amount of residual monomer and the amount of polymer produced, as determined by H-NMR (Bruker, "BBF0400", 400 MHz).

[0148] [Raw materials] The abbreviations of the raw materials used are shown below. (Macromonomer (A)) A-1: PMMA macromonomer (PMMA-Y, Y represents -CH2CH(=CH2)-COOCH3. Mn: 000, Mw / Mn: 1.67) A-2: PMMA macromonomer (PMMA-Y, Y represents -CH2CH(=CH2)-COOCH3. Mn: 12,000, Mw / Mn: 1.67)

[0149] (Vinyl Monomer (B)) BA: n-butyl acrylate MEA: 2-Methoxyethyl acrylate St: styrene THFA: Tetrahydrofurfuryl acrylate PEGA: Poly(ethylene glycol) methyl ether acrylate (Mn=300)

[0150] (Vinyl Monomer (C1)) DGDA: Diethylene glycol diacrylate

[0151] (Organic iodine compounds (D)) CP-I: 2-iodo-2-cyanopropane EPh-I: Ethyl 2-iodophenylacetate

[0152] (Catalyst (E)) BNI: tetra-n-butylammonium iodide

[0153] (Azo-based radical polymerization initiator (F)) AIBN: 2,2'-azobis(isobutyronitrile) PBZ: tert-butyl peroxybenzoate V-40: 1,1'-Azobis(cyclohexane-1-carbonitrile)

[0154] (Catalyst (E), Catalyst (G)) BNI: tetra-n-butylammonium iodide

[0155] (solvent) BuAc: butyl acetate DGME: Diethylene glycol dimethyl ether TOL: Toluene

[0156] (macroinitiator) PMMA-PBA-I: A block copolymer having a block segment made of polymethyl methacrylate (PMMA) and a block segment made of poly(n-butyl alcohol) (PBA), with an iodine atom at the end of the main chain of the block segment made of PBA. PMMA-PMEA-I: A block copolymer having a block segment made of polymethyl methacrylate (PMMA) and a block segment made of poly(2-methoxyethyl acrylate) (PMEA), with an iodine atom at the end of the main chain of the PMEA block segment. PMMA-PSt-I: A block copolymer having a block segment made of PMMA and a block segment made of polystyrene (PSt), with an iodine atom at the end of the main chain of the block segment made of PSt. PMMA-PTHFA-I: A block copolymer having a block segment made of PMMA and a block segment made of polytetrahydrofurfuryl acrylate (PTHFA), with an iodine atom at the end of the main chain of the block segment made of PTHFA. PMMA-PPEGA-I: A block copolymer having a block segment made of PMMA and a block segment made of a polymer chain of poly(ethylene glycol) methyl ether acrylate (PPEGA), and having an iodine atom at the end of the main chain of the block segment made of PPEGA.

[0157] [2-pot synthesis] The preparation of the copolymer in a two-pot synthesis is shown below. (Experimental Example 1) (1) Process (I-1) A polymerizable composition (M11) containing 200 equivalents of BA as the vinyl monomer (B), 1 equivalent of CP-I as the organic iodine compound (D), 1 equivalent of macromonomer (A-1), and 8 equivalents of BNI as the catalyst (E) was prepared. The resulting polymerizable composition (M11) was heated to 110°C and polymerized for 24 hours to obtain a composition containing a block copolymer (PMMA-PBA-I). Table 1 shows the polymerization conditions, monomer conversion, and measurement results of Mn and Mw / Mn of the block copolymer.

[0158] (2) Purification process The composition obtained in step (I-1) was reprecipitated using a mixed solvent of methanol and water (methanol / water mixed solvent (volume ratio) = 8 / 2) as a poor solvent, to recover the block copolymer.

[0159] (3) Process (I-2) A polymerizable composition (M21) was prepared containing 1 equivalent of the purified block copolymer as a macroinitiator, 40 equivalents of DGDA as a vinyl monomer (C1), 8 equivalents of BNI as a catalyst (G), and 70% by weight of BuAc as a solvent. The polymerizable composition (M21) was heated to 110°C and polymerized by reversible complexation-mediated polymerization (RCMP) for 24 hours to obtain a composition containing a copolymer (star polymer, PMMA-PBA Star). The resulting composition was reprecipitated using methanol, a good solvent for the macroinitiator but a poor solvent for the copolymer, to separate the unreacted macroinitiator and vinyl monomer (C) and obtain a copolymer. The purified copolymer was dispersed in tetrahydrofuran (THF) and its particle size was measured using dynamic light scattering (DLS). The polymerization conditions, monomer conversion, macroinitiator conversion, and the measurement results of Mp and peak top particle size of the copolymer are shown in Table 2. The GPC chromatogram obtained by measuring the polymerization in step (I-2) using the GPC peak separation method is shown in Figure 2(a), and the particle size measurement results of the purified copolymer are shown in Figure 2(c).

[0160] (Experimental Example 2) (1) Process (I-1) A composition containing a block copolymer (PMMA-PBA-I) was produced in the same manner as in Experimental Example 1, except that macromonomer (A-2) (Mn=12,000, Mw / Mn=1.67) was used instead of macromonomer (A-1). Table 1 shows the polymerization conditions, monomer conversion, and measurement results of Mn and Mw / Mn of the block copolymer.

[0161] (2) Purification process The composition obtained in step (I-1) was purified by the method of Experimental Example 1, and the block copolymer was recovered.

[0162] (3) Process (I-2) The purified block copolymer was used as a macroinitiator, and polymerization was carried out in the same manner as in Experimental Example 1, except that the amount of DGDA used was 40 equivalents and the polymerization time was changed to 48 hours, to obtain a composition containing a copolymer (star polymer, PMMA-PBA Star). The resulting composition was reprecipitated using methanol to separate the unreacted macroinitiator and vinyl monomer (C) to obtain a copolymer. The purified copolymer was dispersed in THF and its particle size was measured using DLS. The polymerization conditions, monomer conversion, macroinitiator conversion, and the measurement results of Mp and peak top particle size of the copolymer are shown in Table 2. The GPC chromatogram obtained by measuring the polymerization in step (I-2) using the GPC peak separation method is shown in Figure 2(b), and the particle size measurement results of the purified copolymer are shown in Figure 2(c).

[0163] (Experimental Examples 3 to 6) (1) Process (I-1) Compositions containing block copolymers were produced in the same manner as in Experimental Example 1, except that the types and amounts of the vinyl monomer (B), organic iodine compound (D), catalyst (E), azo-based radical polymerization initiator (F), and solvent used in the polymerizable composition (M11) were changed as shown in Table 1, and the polymerization temperature and polymerization time were changed as shown in Table 1. The block copolymer in Experimental Example 3 was PMMA-PMEA-I, the block copolymer in Experimental Example 4 was PMMA-PSt-I, the block copolymer in Experimental Example 5 was PMMA-PTHFA-I, and the block copolymer in Experimental Example 6 was PMMA-PPEGA-I. In Experimental Examples 4 to 6, an azo-based radical polymerization initiator (F) was used to increase the polymerization rate.

[0164] (2) Purification process The composition obtained in step (I-1) was purified by the method of Experimental Example 1, and the block copolymer was recovered.

[0165] (3) Process (I-2) Polymerization was carried out in the same manner as in Experimental Example 1, except that the purified block copolymers shown in Table 2 were used as macroinitiators and the amount of DGDA used and the polymerization time were changed as shown in Table 2, to obtain compositions containing copolymers (star polymers). The block copolymer in Experimental Example 3 was PMMA-PMEA-Star, the block copolymer in Experimental Example 4 was PMMA-PSt-Star, the block copolymer in Experimental Example 5 was PMMA-PTHFA-Star, and the block copolymer in Experimental Example 6 was PMMA-PPEGA-Star. The resulting composition was reprecipitated using methanol to separate the unreacted macroinitiator and vinyl monomer (C) to obtain a copolymer. The purified copolymer was dispersed in THF and its particle size was measured using DLS. The polymerization conditions, monomer conversion, macroinitiator conversion, and the measurement results of Mp and peak top particle size of the copolymer are shown in Table 2. Furthermore, GPC chromatograms obtained by measuring the polymerization in step (I-2) by the GPC peak separation method are shown in Figures 3(a) to 3(c).

[0166] [Table 1]

[0167] [Table 2]

[0168] As shown in Figure 2(a), in Experimental Example 1, the macroinitiator peak gradually attenuated over time, while the copolymer (star polymer) peak increased in both molecular weight and area, suggesting the presence of multiple arm structures. Furthermore, as shown in Figure 2(c), a single peak with a peak top diameter of 63 nm was observed in particle size measurement of the copolymer in Experimental Example 1, suggesting that the copolymer obtained was not aggregated.

[0169] As shown in Table 1, the block copolymer obtained in step (I-1) had an Mn of 22,000 and an Mw / Mn of 2.28 in Experimental Example 1, and an Mn of 23,000 and an Mw / Mn of 2.19 in Experimental Example 2. Thus, even when the Mn of the macromonomer (A) used was increased from 3,900 to 12,000, almost the same block copolymer was obtained, suggesting that an increase in the Mn of the macromonomer (A) does not have a significant effect on an increase in the Mn of the macroinitiator.

[0170] In Experimental Example 2, the monomer conversion rate 24 hours after the initiation of polymerization in step (I-2) was 25%, and as shown in Figure 2(b), a shoulder peak with a peak-top molecular weight Mp of 520,000 appeared on the high-molecular-weight side of the chromatogram. Furthermore, the macroinitiator conversion rate 24 hours after the initiation of polymerization was 18%, which was slower than the conversion rate of 43% in Experimental Example 1. Forty-eight hours after the initiation of polymerization, the monomer conversion rate was 35%, and the macroinitiator conversion rate was 25%, meaning that 75% of the macroinitiator had lost the iodine atom at the end of its main chain and remained unreacted. The copolymer obtained in Experimental Example 2 exhibited a single peak with a peak-top diameter of 79 nm, and had a larger particle size than the copolymer obtained in Experimental Example 1. This is thought to be because the macroinitiator produced from macromonomer (A-2) has a longer chain length and greater steric hindrance than the macroinitiator using macromonomer (A-2), and therefore requires the bonding of more structural units (c1) derived from vinyl monomer (C1) before effective crosslinking can proceed at the center in step (I-2).

[0171] As shown in Tables 1 and 2 and Figures 3(a) to 3(c), in Experimental Examples 3 to 6, copolymers could be produced from the macroinitiators as in Examples 1 and 2. When DLS measurements were performed on these copolymers, no aggregation was observed.

[0172] [One-pot synthesis] The preparation of the copolymer in a one-pot synthesis is shown below. (Experimental Example 7) (1) Process (I-1) A polymerizable composition (M11) containing 200 equivalents of BA as the vinyl monomer (B), 1 equivalent of CP-I as the organic iodine compound (D), 1 equivalent of macromonomer (A-1), and 8 equivalents of BNI as the catalyst (E) was prepared. The resulting polymerizable composition (M11) was heated to 110°C and polymerized for 24 hours to obtain a composition containing a block copolymer (PMMA-PBA-I). The BA conversion was 83%, and the Mn of the block copolymer was 21,000, with Mw / Mn being 2.15. Table 3 shows the polymerization conditions, the monomer conversion rate, and the measurement results of Mn and Mw / Mn of the block copolymer.

[0173] (2) Process (I-2) To the composition obtained in step (I-1), without further purification, 40 equivalents of DGDA as the vinyl monomer (C1), 4 equivalents of BNI as the catalyst (G), and BuAc as the solvent were added to prepare a polymerizable composition (M21) in which the proportion of BuAc relative to the total of the BA, DGDA, and BuAc added in step (I-1) was 70 mass%. The polymerizable composition (M21) contained unreacted BA (17% of the initial amount), and this unreacted BA can be considered as the vinyl monomer (C2) in the polymerizable composition (M21). The polymerizable composition (M21) was heated to 110°C and polymerized for 48 hours (72 hours in total from the start of polymerization in step (I-1)), yielding a composition containing a copolymer (star polymer, PMMA-PBA-Star). The resulting copolymer had a slightly low crosslink density because the block segments forming the core structure contained structural units derived from BA, a non-crosslinkable monomer. The resulting composition was reprecipitated using methanol to separate the unreacted macroinitiator and vinyl monomer (C) to obtain a copolymer. The purified copolymer was dispersed in THF and its particle size was measured using DLS. The polymerization conditions, monomer conversion, macroinitiator conversion, and the measurement results of Mp and peak top particle size of the copolymer are shown in Table 4. In addition, the GPC chromatogram obtained by measuring the polymerization from step (I-1) using the GPC peak separation method is shown in Figure 4(a), and the particle size measurement results of the purified copolymer are shown in Figure 4(c).

[0174] (Experimental Example 8) (1) Process (I-1) Polymerization was carried out in the same manner as in Experimental Example 7, except that the polymerization time was changed from 24 hours to 16 hours, to produce a composition containing a block copolymer (PMMA-PBA-I). The BA conversion rate was 68%, the Mn of the block copolymer was 18,000, and Mw / Mn was 2.11. Compared with Experimental Example 7, the polymer chains of the block copolymer were shorter. Table 3 shows the polymerization conditions, the monomer conversion rate, and the measurement results of Mn and Mw / Mn of the block copolymer.

[0175] (2) Process (I-2) Using the composition obtained in step (I-1), polymerization was carried out for 48 hours (a total of 72 hours from the start of polymerization in step (I-1)) in the same manner as in Experimental Example 7, to obtain a composition containing a copolymer (star polymer, PMMA-PBA-Star). The resulting composition was reprecipitated using methanol to separate the unreacted macroinitiator and vinyl monomer (C) to obtain a copolymer. The purified copolymer was dispersed in THF and its particle size was measured using DLS. The polymerization conditions, monomer conversion, macroinitiator conversion, and the measurement results of Mp and peak-top particle size of the copolymer are shown in Table 4. In addition, the GPC chromatogram obtained by measuring the polymerization from step (I-1) using the GPC peak separation method is shown in Figure 4(b), and the particle size measurement results of the purified copolymer are shown in Figure 4(c).

[0176] (Experimental Example 9) (1) Process (I-1) A composition containing a block copolymer (PMMA-PTHFA-I) was produced in the same manner as in Experimental Example 1, except that the types and amounts of the vinyl monomer (B), azo radical polymerization initiator (F), and solvent used in the polymerizable composition (M11), and the polymerization time were changed as shown in Table 3. In Experimental Example 9, an azo radical polymerization initiator (F) was used to increase the polymerization rate. The THFA conversion was 65%, and the Mn of the block copolymer was 14,000, with Mw / Mn being 1.99. Table 3 shows the polymerization conditions, the monomer conversion rate, and the measurement results of Mn and Mw / Mn of the block copolymer.

[0177] (2) Process (I-2) The purified block copolymer shown in Table 4 was used as a macroinitiator, and polymerization was carried out in the same manner as in Experimental Example 7, except that the amount of BNI used, the polymerization temperature, and the polymerization time were changed as shown in Table 4, to obtain a composition containing a copolymer (star polymer, PMMA-PTHFA-Star). The DGDA conversion was 83% and the BA conversion was 92%, both of which were desirable for industrial applications. The macroinitiator conversion was 30%, and the copolymer Mp was 1,200,000. The resulting composition was reprecipitated using methanol to separate the unreacted macroinitiator and vinyl monomer (C) to obtain a copolymer. The purified copolymer was dispersed in THF and its particle size was measured using DLS. The polymerization conditions, monomer conversion, macroinitiator conversion, and the measurement results of Mp and peak top particle size of the copolymer are shown in Table 4. In addition, the GPC chromatogram obtained by measuring the polymerization from step (I-1) using the GPC peak separation method is shown in Figure 5(a), and the particle size measurement results of the copolymer after purification are shown in Figure 5(b).

[0178] [Table 3]

[0179] [Table 4]

[0180] As shown in Tables 3 and 4 and FIG. 4(a), in Experimental Example 7, when the polymerization time in step (I-2) reached 24 hours (a total of 48 hours from the start of polymerization in step (I-1)), the peak only shifted slightly to the high molecular weight region, and Mn increased to 27,000. Furthermore, when the polymerization time in step (I-2) reached 24 hours, compared to Experimental Example 1 (2-pot synthesis), in which 43% of the macroinitiator was converted to a copolymer (star polymer), crosslinking was delayed in Experimental Example 7 (1-pot synthesis) due to the presence of BA, a non-crosslinkable monomer. When the polymerization time in step (I-2) reached 48 hours (a total of 72 hours from the start of polymerization in step (I-1)), the DGDA conversion rate increased to 50% and the BA conversion rate increased to 91% (83% at the start of polymerization in step (I-2)). In Experimental Example 1 of the two-pot synthesis, the conversion rate of the macroinitiator was 43% and the peak top molecular weight Mp of the copolymer was 510,000, whereas in Experimental Example 7, the conversion rate of the macroinitiator was 35% and the peak top molecular weight Mp of the copolymer was 470,000, both of which were smaller values. This is thought to be because, as the polymerization time increased, iodine atoms were lost from the main chain ends, resulting in the production of more polymer chains in which the polymerization was terminated. As shown in Figure 4(c), DLS analysis of the copolymer revealed a single peak with a peak top of 68 nm, suggesting the formation of a relatively uniform copolymer (star polymer) without aggregation.

[0181] As shown in Tables 3 and 4 and FIG. 4(b), in Experimental Example 8, when the polymerization time in step (I-2) was 48 hours (a total of 64 hours from the start of polymerization in step (I-1)), the DGDA conversion was 62% and the BA conversion was 91%, indicating that 23% of BA-derived structural units were incorporated into the core structure of the copolymer. In Experimental Example 8, 40% of the macroinitiator was converted into a copolymer (Mp=580000), and the polymerizable composition (M21) contained a large amount of unreacted BA (32%), which delayed the progress of crosslinking and resulted in a copolymer with a larger core structure and lower crosslink density. As shown in Figure 4(c), DLS analysis of the copolymer revealed a single peak with a peak top of 79 nm, suggesting the formation of a relatively uniform copolymer (star polymer) without aggregation.

[0182] As shown in Tables 3 and 4 and FIG. 5(a), 30% of the macroinitiator was converted into a copolymer (Mp=1200000) after 2 hours of polymerization in step (I-2) (a total of 3 hours from the start of polymerization in step (I-1)). As shown in FIG. 5(b), in the DLS analysis of the copolymer of Experimental Example 9, a single peak with a peak top of 91 nm appeared, suggesting the formation of a relatively uniform copolymer (star polymer) without aggregation.

[0183] [Production of UVA-impregnated particles] The impregnation of ultraviolet absorber (UVA) into copolymers whose arm structure is a polymer chain of PMMA-PTHFA was investigated.

[0184] (Experimental Example 10) The copolymer obtained in Experimental Example 9 was dissolved in THF at 50°C, and the polymer solution was saturated with an ultraviolet absorber (UVA). The polymer solution was stirred for 2 hours, allowing the UVA to penetrate into the core structure of the copolymer. Next, hexane, a non-solvent for the copolymer but a poor solvent for UVA, was added dropwise to slowly precipitate and collect the UVA-impregnated particles, which contained 40% UVA by mass.

[0185] (Experimental Example 11) UVA-impregnated particles were produced in the same manner as in Experimental Example 10, except for using the copolymer obtained in Experimental Example 5. The UVA content in the UVA-impregnated particles was 13 mass %.

[0186] The UVA content of the UVA-impregnated particles was 13% by mass in Experimental Example 11, while it was a very high 40% by mass in Experimental Example 10. This result indicates that the copolymer of Experimental Example 10 obtained by one-pot synthesis has a larger core structure and lower crosslinking density than the copolymer obtained by two-pot synthesis, making it easier to impregnate with UVA and improving encapsulation ability.

[0187] [Production of PMMA film with UVA added] Next, we investigated the incorporation of UVA-impregnated particles, which were made by impregnating a copolymer whose arm structure was a polymer chain of PMMA-PTHFA with UVA, into a PMMA film. The PMMA arm-structured block segments interact with the binder matrix, while the PTHFA block segments interact with UVA molecules. Furthermore, because the refractive index of THFA (1.460) is close to that of MMA (1.414), blending PTHFA does not significantly reduce the transparency of the PMMA film.

[0188] (Experimental Example 12) 0.300 g of PMMA (Mn: 45000) was dissolved in BuAc to prepare 2.00 g of PMMA solution, which was then coated on a substrate and dried to prepare a PMMA film with a thickness of 100 μm.

[0189] (Experimental Example 13) A PMMA film was produced in the same manner as in Experimental Example 12, except that 2.00 g of a PMMA solution was prepared by dissolving 0.0400 g of UVA and 0.300 g of PMMA (Mn: 45000) in BuAc, and the mass ratio of UVA:PMMA was 11.8:88.2.

[0190] (Experimental Example 14) A PMMA film was produced in the same manner as in Experimental Example 12, except that 2.00 g of PMMA solution was prepared by dissolving 0.0600 g of the UVA-impregnated particles obtained in Experimental Example 10 and 0.300 g of PMMA (Mn: 45000) in BuAc, and the mass ratio of UVA:copolymer:PMMA was 6.7:10.0:83.3.

[0191] (Experimental Example 15) A PMMA film was produced in the same manner as in Experimental Example 12, except that 2.00 g of a PMMA solution was prepared by dissolving 0.0200 g of UVA, 0.0600 g of the UVA-impregnated particles obtained in Experimental Example 10, and 0.300 g of PMMA (Mn: 45000) in BuAc, and the mass ratio of UVA:copolymer:PMMA was 11.6:9.5:78.9.

[0192] The compositions of the PMMA solutions in Experimental Examples 12 to 15 are shown in Table 5. The UV-visible transmission spectra (200 to 800 nm) of the PMMA films in each example were measured using a UV-Vis spectrophotometer, and the results are shown in Figure 6.

[0193] [Table 5]

[0194] As shown in Figure 6, the PMMA film of Experimental Example 12 exhibits absorption only in the UV-C region (wavelengths less than 280 nm) and exhibits a transmittance of 90% or more in the UV-B and UV-A regions (regions of 260 to 400 nm). On the other hand, the PMMA films of Experimental Examples 13 to 15, which contained UVA, maintained relatively high transmittance (>75%) in the visible light region (400-800 nm) and were able to effectively reduce transmittance to 0% across the entire UV region (200-400 nm). The average transmittance in the visible light region (400-800 nm) of Experimental Examples 13 to 15 was 5%, 11%, and 13%, respectively, lower than that of Example 12, but the appearance (transparency) of the film was not impaired. As described above, we were able to prepare a PMMA film containing UVA-impregnated particles.

Claims

1. The polymer has a plurality of block segments A derived from a macromonomer (A), a plurality of block segments B consisting only of structural units (b) derived from a vinyl monomer (B) having one vinyl group in the molecule, and a plurality of block segments C in which the proportion of structural units (c1) derived from a vinyl monomer (C1) having two or more vinyl groups in the molecule is 10 mol % or more, A copolymer, wherein the plurality of block segments C are crosslinked to each other to form a crosslinked structure, and the crosslinked structure has an iodine terminal.

2. The copolymer according to claim 1 , wherein the block segment B has a branched structure, and the main chain and the branched chains are the same structural units.

3. The copolymer according to claim 1 , wherein the macromonomer (A) is a macromonomer represented by the following formula (I): 【Chemical 1】 (In formula (I), R and R １ ~R ｎ are each independently a hydrogen atom, an alkyl group, a cycloalkyl group, an aryl group, or a heterocyclic group. Z is a hydrogen atom or a group derived from a radical polymerization initiator. X １ ~X ｎ are each independently a hydrogen atom or a methyl group, and n is an integer of 2 to 10,000.

4. 2. The copolymer according to claim 1, wherein the vinyl monomer (B) is at least one selected from the group consisting of styrene-based monomers, methacrylate-based monomers, and acrylate-based monomers.

5. A method for producing a macroinitiator comprising polymerizing a polymerizable composition (M11) containing a macromonomer (A), a vinyl monomer (B) having one vinyl group in the molecule, and an organic iodine compound (D) to obtain a macroinitiator comprising a block copolymer; polymerizing a polymerizable composition (M21) comprising the macroinitiator and a vinyl monomer (C), The method for producing a copolymer, wherein the vinyl monomer (C) contains 10 mol % or more of a vinyl monomer (C1) having two or more vinyl groups in the molecule.

6. The method for producing a copolymer according to claim 5 , wherein the macromonomer (A) is a macromonomer represented by the following formula (I): 【Chemistry 2】 (In formula (I), R and R １ ~R ｎ are each independently a hydrogen atom, an alkyl group, a cycloalkyl group, an aryl group, or a heterocyclic group. Z is a hydrogen atom or a group derived from a radical polymerization initiator. X １ ~X ｎ are each independently a hydrogen atom or a methyl group, and n is an integer of 2 to 10,000.

7. The method for producing a copolymer according to claim 5 , wherein the polymerizable composition (M11) further contains one or both of a catalyst (E) and an azo-based radical polymerization initiator (F).

8. The method for producing a copolymer according to claim 5 , wherein the polymerizable composition (M21) further contains a catalyst (G).

9. The method for producing a copolymer according to claim 5, further comprising purifying the composition obtained by polymerizing the polymerizable composition (M11) to recover the macroinitiator.

10. 6. The method for producing a copolymer according to claim 5, wherein the composition obtained by polymerizing the polymerizable composition (M11) is not purified, and the vinyl monomer (C1) is added to the composition, and polymerization is carried out to obtain the polymerizable composition (M21).

11. obtaining a macroinitiator comprising a block copolymer by polymerizing a polymerizable composition (M12) containing a macromonomer (A), a vinyl monomer (B) having one vinyl group in the molecule, an azo radical polymerization initiator (F), and iodine; polymerizing a polymerizable composition (M22) comprising the macroinitiator and a vinyl monomer (C), The method for producing a copolymer, wherein the vinyl monomer (C) contains 10 mol % or more of a vinyl monomer (C1) having two or more vinyl groups in the molecule.

12. The method for producing a copolymer according to claim 11, wherein the macromonomer (A) is a macromonomer represented by the following formula (I): 【Chemistry 3】 (In formula (I), R and R １ ~R ｎ are each independently a hydrogen atom, an alkyl group, a cycloalkyl group, an aryl group, or a heterocyclic group. Z is a hydrogen atom or a group derived from a radical polymerization initiator. X １ ~X ｎ are each independently a hydrogen atom or a methyl group, and n is an integer of 2 to 10,000.

13. The method for producing a copolymer according to claim 11, wherein the polymerizable composition (M12) further comprises a catalyst (E).

14. The method for producing a copolymer according to claim 11, wherein the polymerizable composition (M22) further contains a catalyst (G).

15. The method for producing a copolymer according to claim 11, further comprising purifying the composition obtained by polymerizing the polymerizable composition (M12) to recover the macroinitiator.

16. The method for producing a copolymer according to claim 11, wherein the composition obtained by polymerizing the polymerizable composition (M12) is not purified, and the vinyl monomer (C1) is added to the composition, and polymerization is carried out to obtain the polymerizable composition (M22).

17. 12. The method for producing a copolymer according to claim 5 or 11, wherein the vinyl monomer (B) is at least one selected from the group consisting of a styrene-based monomer, a methacrylate-based monomer, and an acrylate-based monomer.

18. 5. A low-molecular-weight compound-impregnated particle obtained by impregnating the copolymer according to claim 1 with a low-molecular-weight compound having a molecular weight of 1,000 or less.

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