WO2024020780A1 - Star-shaped polymer, paint, coating, and method for producing star-shaped polymer - Google Patents

Star-shaped polymer, paint, coating, and method for producing star-shaped polymer Download PDF

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Publication number
WO2024020780A1
WO2024020780A1 PCT/CN2022/107909 CN2022107909W WO2024020780A1 WO 2024020780 A1 WO2024020780 A1 WO 2024020780A1 CN 2022107909 W CN2022107909 W CN 2022107909W WO 2024020780 A1 WO2024020780 A1 WO 2024020780A1
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star
shaped polymer
polymer
polymerization
block
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PCT/CN2022/107909
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French (fr)
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Shizheng HOU
Hisakazu Tanaka
Chao Wang
Juyan HAN
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Dic Corporation
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    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08F—MACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS
    • C08F293/00—Macromolecular compounds obtained by polymerisation on to a macromolecule having groups capable of inducing the formation of new polymer chains bound exclusively at one or both ends of the starting macromolecule
    • C08F293/005—Macromolecular compounds obtained by polymerisation on to a macromolecule having groups capable of inducing the formation of new polymer chains bound exclusively at one or both ends of the starting macromolecule using free radical "living" or "controlled" polymerisation, e.g. using a complexing agent
    • C—CHEMISTRY; METALLURGY
    • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
    • C09J—ADHESIVES; NON-MECHANICAL ASPECTS OF ADHESIVE PROCESSES IN GENERAL; ADHESIVE PROCESSES NOT PROVIDED FOR ELSEWHERE; USE OF MATERIALS AS ADHESIVES
    • C09J153/00—Adhesives based on block copolymers containing at least one sequence of a polymer obtained by reactions only involving carbon-to-carbon unsaturated bonds; Adhesives based on derivatives of such polymers
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08F—MACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS
    • C08F2438/00—Living radical polymerisation
    • C08F2438/01—Atom Transfer Radical Polymerization [ATRP] or reverse ATRP

Definitions

  • the present invention relates to a star-shaped polymer, a paint, a coating, and a method for producing a star-shaped polymer.
  • base polymers having a higher molecular weight are more preferable in terms of properties such as heat resistance in various applications of polymers.
  • the conventional approach of increasing the molecular weight of a linear polymer to a larger molecular structure results in a high viscosity of the polymer solution and consequently causes problems, such as difficulty in application of the polymer solution, encountered when the polymer is being used.
  • star-shaped polymers which are currently under development (for example, PTL 1 and PTL 2) .
  • a method for preparing a star-shaped polymer As a method for preparing a star-shaped polymer, a method (a core first method) is known in which a star-shaped polymer is obtained by performing polymerization reaction using an initiator having a plurality of initiation points. In this method, however, it is difficult to increase the number of initiation points. While some studies have reported that a star-shaped polymer having 10 or more arms is produced using a core compound having a partial cyclodextrin skeleton (see, for example, NPL 1 and NPL 2) , increasing the number of arms raises the risk of gelation and makes industrial production difficult.
  • star-shaped polymers in which the arms are composed of a polymer of blocks having different compositions from one another the disclosure is limited to, for example, production methods using a photoinitiator, and small-scale special production methods using a coupling technique.
  • NPL 1 Xiuzhe Yin et al., European Polymer Journal 126 (2020) 109557.
  • NPL 2 F. J. Xu et al., Biomacromolecules, Vol. 10, No. 2, (2009) 285-293.
  • An object of the present invention is to provide a star-shaped polymer capable of giving a coating with excellent mechanical properties, a paint containing the star-shaped polymer, a coating having excellent mechanical properties, and a star-shaped polymer production method capable of producing the star-shaped polymer described above.
  • the present inventors carried out extensive studies directed to achieving the above object, and have consequently found that the object can be achieved by a star-shaped polymer that is obtained by performing living radical polymerization while using a cyclodextrin skeleton-containing compound as an initiator in such a manner that a monofunctional vinyl compound as a first block constituent component is polymerized beforehand to form an intermediate polymer as a macroinitiator, and further a monofunctional vinyl compound as a second block constituent component is polymerized to form a second block.
  • the present invention has been completed based on the finding.
  • aspects of the present invention include the following:
  • an arm portion being a polymer chain bonded to the core portion, the arm portion including a first block and a second block, the first block being located on a side of the polymer chain adjacent to the core portion and bonded to the core portion, the second block being located on a tip side of the polymer chain, the method including:
  • a step of preparing an intermediate polymer by performing living radical polymerization of a monofunctional vinyl compound as a first block constituent component in the presence of a catalyst while using as an initiator a cyclodextrin skeleton-containing compound having polymerization initiation groups serving as initiation points for polymerization, to prepare an intermediate polymer including the core portion and a plurality of the first blocks each including a structural unit derived from the monofunctional vinyl compound and bonded to an initiation point of the core portion;
  • a step of preparing a star-shaped polymer by performing living radical polymerization of a monofunctional vinyl compound as a second block constituent component in the presence of a catalyst while using the intermediate polymer as a macroinitiator, to prepare a star-shaped polymer including the core portion, the first blocks, and a plurality of the second blocks each including a structural unit derived from the monofunctional vinyl compound and bonded to the first block.
  • the monofunctional vinyl compound as the second block constituent component is a (meth) acrylic acid compound.
  • R 1 independently denotes a hydrogen atom or a 2-bromoisobutyryl group, and *denotes a bond.
  • the star-shaped polymer provided according to the present invention can give a coating having excellent mechanical properties.
  • the paint provided according to the present invention contains the star-shaped polymer.
  • the coating provided according to the present invention has excellent mechanical properties.
  • Fig. 1 is a GPC chart of a star-shaped polymer prepared in Example 1.
  • Fig. 2 is a GPC chart of a star-shaped polymer prepared in Example 2.
  • Fig. 3 is a GPC chart of a star-shaped polymer prepared in Example 3.
  • Fig. 4 is a GPC chart of a star-shaped polymer prepared in Example 4.
  • Fig. 5 is a GPC chart of a star-shaped polymer prepared in Example 5.
  • Fig. 6 is a GPC chart of a star-shaped polymer prepared in Example 6.
  • Fig. 7 is a GPC chart of a star-shaped polymer prepared in Example 7.
  • Fig. 8 is a GPC chart of a star-shaped polymer prepared in Example 8.
  • Fig. 9 is a GPC chart of a star-shaped polymer prepared in Comparative Example 1.
  • Fig. 10 is a GPC chart of a star-shaped polymer prepared in Reference Example 1.
  • Fig. 11 is a GPC chart of a star-shaped polymer prepared in Reference Example 2.
  • Fig. 12 is a diagram illustrating tensile test results of the star-shaped polymers prepared in Examples 2 to 5.
  • Fig. 13 is a diagram illustrating tensile test results of the star-shaped polymers prepared in Examples 6 to 8.
  • a star-shaped polymer according to the present invention includes a core portion and an arm portion.
  • the arm portion is bonded to the core portion.
  • a plurality of arm portions are usually bonded to the core portion.
  • the arm portions extend radially from the core portion.
  • the core portion includes a cyclodextrin skeleton-containing compound (hereinafter, sometimes abbreviated as the CD skeleton-containing compound) as a constituent component.
  • a cyclodextrin skeleton-containing compound hereinafter, sometimes abbreviated as the CD skeleton-containing compound
  • the CD skeleton-containing compound according to the present invention is characterized in that the hydroxy groups present in the cyclodextrin are partially or completely substituted with a compound that has a polymerization initiation group capable of serving as an initiation point for living radical polymerization.
  • the CD skeleton-containing compound is a cyclodextrin derivative that has a polymerization initiation group capable of serving as an initiation point for living radical polymerization at an end.
  • the cyclodextrins are a type of cyclic oligosaccharides having a cyclic structure of D-glucose molecules joined by ⁇ - (1 ⁇ 4) glucoside bonds. Examples thereof include ⁇ -cyclodextrin formed by bonding of six D-glucose molecules, ⁇ -cyclodextrin formed by bonding of seven D-glucose molecules, and ⁇ -cyclodextrin formed by bonding of eight D-glucose molecules.
  • ⁇ -cyclodextrin formed by bonding of seven D-glucose molecules is preferable because ⁇ -cyclodextrin has excellent reactivity with a compound having a polymerization initiation group and has excellent stability.
  • the polymerization initiation group is not particularly limited and may be any functional group capable of serving as an initiation point for living radical polymerization.
  • ⁇ -haloacyloxy groups, ⁇ -haloacyl groups and halosulfonyl groups are preferable because of their excellent reactivity, and ⁇ -haloacyloxy groups and ⁇ -haloacyl groups are more preferable.
  • halogen atoms contained independently in each of the ⁇ -haloacyloxy groups, the ⁇ -haloacyl groups and the halosulfonyl groups include chlorine atom, bromine atom and iodine atom, with chlorine atom and bromine atom being preferable from the point of view of reactivity.
  • Examples of the ⁇ -haloacyloxy groups include 2-chloroisobutyryloxy group, 2-bromoisobutyryloxy group, 2-iodoisobutyryloxy group, 2-chlorobutyryloxy group, 2-bromobutyryloxy group, 2-iodobutyryloxy group, 2-chloropropionyloxy group, 2-bromopropionyloxy group, 2-iodopropionyloxy group, chlorophenylacetoxy group, bromophenylacetoxy group and iodophenylacetoxy group.
  • Examples of the ⁇ -haloacyl groups include 2-chloroisobutyryl group, 2-bromoisobutyryl group, 2-iodoisobutyryl group, 2-chlorobutyryl group, 2-bromobutyryl group, 2-iodobutyryl group, 2-chloropropionyl group, 2-bromopropionyl group, 2-iodopropionyl group, dichloroacetyl group, dibromoacetyl group and diiodoacetyl group.
  • 2-chloroisobutyryl group and 2-bromoisobutyryl group are preferable because of their excellent polymerization initiation properties, and 2-bromoisobutyryl group is more preferable.
  • a linking group may be present between the hydroxy group in the cyclodextrin, and the polymerization initiation group.
  • the linking groups include C 1 -C 20 alkylene groups such as methylene group, ethylene group, trimethylene group, tetramethylene group, hexamethylene group, decamethylene group and dodecamethylene group, derivative of these groups, -O-group and -S-group.
  • a C 2 -C 10 alkylene group is preferable as the linking group because excellent reactivity is obtained.
  • the number of polymerization initiation groups present in the CD skeleton-containing compound is not particularly limited.
  • the hydroxy groups in the cyclodextrin may be completely or partially substituted with the polymerization initiation groups.
  • the number of polymerization initiation groups is preferably 4 or more, more preferably 7 or more, and still more preferably 14 or more.
  • CD skeleton- containing compound for example, a preferred example of the CD skeleton- containing compound described above is a compound represented by the formula (1) below.
  • the compound represented by the formula (1) is ⁇ -cyclodextrin in which the hydroxy groups are partially or completely substituted with a 2-bromoisobutyryl group.
  • R 1 independently denotes a hydrogen atom or a 2-bromoisobutyryl group, and *denotes a bond.
  • the number of 2-bromoisobutyryl groups is not particularly limited.
  • the number of 2-bromoisobutyryl groups is preferably 4 or more, more preferably 7 or more, and still more preferably 14 or more.
  • the upper limit of the number of 2-bromoisobutyryl groups in the formula (1) is 21.
  • the arm portion is a polymer chain.
  • the polymer chain is usually linear.
  • the arm portion includes a first block located on a side of the polymer chain adjacent to the core portion and bonded to the core portion, and a second block located on a tip side of the polymer chain.
  • tip side indicates an end of the arm portion opposite from the end adjacent to the core portion.
  • the mass ratio of the first block to the second block is not particularly limited, but from the point of view of the balance of mechanical properties, the mass ratio is preferably 5: 95 to 95: 5, more preferably 30: 70 to 70: 30, and particularly preferably 35: 65 to 55: 45.
  • the first block and the second block each independently include, as a constituent component, a monofunctional vinyl compound having one polymerizable vinyl group.
  • the first block and the second block may each independently include a single kind of a monofunctional vinyl compound as a constituent component, or two or more kinds of monofunctional vinyl compounds as constituent components.
  • Examples of the polymerizable vinyl groups include vinyl group, acryloyloxy group, methacryloyloxy group and allyl group.
  • Examples of the monofunctional vinyl compounds include (meth) acrylic acid compounds, (meth) acrylamide compounds, styrenes, allyl esters, vinyl ethers, vinyl esters and crotonic acid esters.
  • Examples of the (meth) acrylic acid compounds include (meth) acrylic acid and (meth) acrylic acid esters.
  • (meth) acrylic acid esters examples include aliphatic (meth) acrylic acid esters such as methyl (meth) acrylate, ethyl (meth) acrylate, n-propyl (meth) acrylate, isopropyl (meth) acrylate, n-butyl (meth) acrylate, isobutyl (meth) acrylate, t-butyl (meth) acrylate, n-pentyl (meth) acrylate, isopentyl (meth) acrylate, neopentyl (meth) acrylate, hexyl (meth) acrylate, heptyl (meth) acrylate, n-octyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, isooctyl (meth) acrylate, n-nonyl (meth) acrylate, isononyl (
  • Examples further include (meth) acrylic acid esters having an amino group, such as dimethylaminoethyl (meth) acrylate, diethylaminoethyl (meth) acrylate, N-tert-butylaminoethyl (meth) acrylate and (meth) acryloxyethyltrimethylammonium chloride.
  • (meth) acrylic acid esters having an amino group such as dimethylaminoethyl (meth) acrylate, diethylaminoethyl (meth) acrylate, N-tert-butylaminoethyl (meth) acrylate and (meth) acryloxyethyltrimethylammonium chloride.
  • Examples of the (meth) acrylamide compounds include (meth) acrylamide; (meth) acrylonitrile; N-monosubstituted (meth) acrylamide monomers such as N-methylol (meth) acrylamide, N-methoxymethyl (meth) acrylamide, N-butoxymethyl (meth) acrylamide, N-isopropyl (meth) acrylamide and dimethylaminopropyl (meth) acrylamide; and N, N-disubstituted (meth) acrylamide monomers such as N- (meth) acryloylmorpholine, N- (meth) acryloylpyrrolidone, N- (meth) acryloylpiperidine, N- (meth) acryloylpyrrolidine, N- (meth) acryloyl-4-piperidone, N, N-dimethyl (meth) acrylamide and N, N-diethyl (meth) acrylamide.
  • styrenes examples include styrene, tert-butoxystyrene, ⁇ -methyl-tert-butoxystyrene, 4- (1-methoxyethoxy) styrene, 4- (1-ethoxyethoxy) styrene, tetrahydropyranyloxystyrene, adamantyloxystyrene, 4- (2-methyl-2-adamantyloxy) styrene, 4- (1-methylcyclohexyloxy) styrene, trimethylsilyloxystyrene, dimethyl-tert-butylsilyloxystyrene, tetrahydropyranyloxystyrene, benzylstyrene, trifluoromethylstyrene, acetoxystyrene, chlorostyrene, dichlorostyrene, trichlorostyrene, tetrachlorostyren
  • allyl esters examples include allyl acetate, allyl caproate, allyl caprylate, allyl laurate, allyl palmitate, allyl stearate, allyl benzoate, allyl acetoacetate, allyl lactate and allyloxyethanol.
  • vinyl ethers examples include hexyl vinyl ether, octyl vinyl ether, decyl vinyl ether, ethylhexyl vinyl ether, methoxyethyl vinyl ether, ethoxyethyl vinyl ether, chloroethyl vinyl ether, 1-methyl-2, 2-dimethylpropyl vinyl ether, 2-ethylbutyl vinyl ether, hydroxyethyl vinyl ether, diethylene glycol vinyl ether, dimethylaminoethyl vinyl ether, diethylaminoethyl vinyl ether, butylaminoethyl vinyl ether, benzyl vinyl ether, tetrahydrofurfuryl vinyl ether, vinyl phenyl ether, vinyl tolyl ether, vinyl chlorophenyl ether, vinyl-2, 4-dichlorophenyl ether, vinyl naphthyl ether and vinyl anthranyl ether.
  • vinyl esters examples include vinyl butyrate, vinyl isobutyrate, vinyl trimethylacetate, vinyl diethylacetate, vinyl valerate, vinyl caproate, vinyl chloroacetate, vinyl dichloroacetate, vinyl methoxyacetate, vinyl butoxyacetate, vinyl phenylacetate, vinyl acetoacetate, vinyl lactate, vinyl- ⁇ -phenylbutyrate and vinyl cyclohexylcarboxylate.
  • crotonic acid esters examples include butyl crotonate, hexyl crotonate, glycerol monocrotonate, dimethyl itaconate, diethyl itaconate, dibutyl itaconate, dimethyl maleate, dibutyl fumarate, maleic anhydride, maleimide, acrylonitrile, methacrylonitrile and maleonitrile.
  • the monofunctional vinyl compounds may have a heteroatom other than oxygen atom or may be free from heteroatoms other than oxygen atoms.
  • the monofunctional vinyl compounds may have a nitrogen atom or may be free from nitrogen atoms.
  • the monofunctional vinyl compounds may have a sulfur atom or may be free from sulfur atoms.
  • the monofunctional vinyl compounds may have a halogen atom or may be free from halogen atoms.
  • (meth) acrylic acid compounds are preferable as the monofunctional vinyl compounds used in the first block and the second block because excellent mechanical properties are obtained.
  • (Meth) acrylic acid esters are more preferable, and aliphatic (meth) acrylic acid esters are still more preferable.
  • the monofunctional vinyl compound used in the first block is preferably n-butyl acrylate (hereinafter, sometimes abbreviated as nBA)
  • the monofunctional vinyl compound used in the second block is preferably methyl methacrylate (hereinafter, sometimes abbreviated as MMA) , although not particularly limited thereto.
  • the number average molecular weight (Mn) of the arm portion measured by gel permeation chromatography (GPC (RI) ) is not particularly limited, but is preferably 10,000 or more in order to obtain a coating with higher mechanical properties, and is more preferably 15,000 or more, still more preferably 20,000 or more, and particularly preferably 25,000 or more.
  • the upper limit of the number average molecular weight (Mn) is not particularly limited.
  • the number average molecular weight (Mn) may be 100,000 or less, may be 60,000 or less, or may be 50,000 or less.
  • the GPC (RI) number average molecular weight (Mn) may be determined by the following GPC (RI) measurement method.
  • Measurement device High-performance GPC device ( "HLC-8220GPC” manufactured by Tosoh Corporation)
  • RI differential refractometer
  • Sample A tetrahydrofuran solution having a resin solid concentration of 0.5 mass%is microfiltered (100 ⁇ l) .
  • the number average molecular weight of the arm portion may be determined by, for example, synthesizing the arm portion by living radical polymerization and subjecting the arm portion alone to the method described above.
  • the mass ratio of the core portion to the arm portion is not particularly limited, but is preferably 1: 99 to 99: 1, more preferably 1: 99 to 50: 50, still more preferably 3: 97 to 40: 60, and particularly preferably 5: 95 to 20: 80.
  • the number average molecular weight (Mn) of the star-shaped polymer measured by gel permeation chromatography (GPC (RI) ) is not particularly limited, but is preferably 100,000 or more in order to obtain a coating with higher mechanical properties, and is more preferably 200,000 or more, and particularly preferably 300,000 or more.
  • the upper limit of the number average molecular weight (Mn) is not particularly limited.
  • the number average molecular weight (Mn) may be 1,000,000 or less, may be 800,000 or less, or may be 700,000 or less.
  • the weight average molecular weight (Mw) of the star-shaped polymer measured by size-exclusion chromatography (GPC/SEC) is 100,000 or more, and, in order to obtain a coating with higher mechanical properties, is preferably 200,000 or more, more preferably 300,000 or more, and particularly preferably 400,000 or more.
  • the weight average molecular weight (Mw) of the star-shaped polymer is 100,000 or more. If the weight average molecular weight (Mw) of the star-shaped polymer is less than 100,000, a coating having excellent mechanical properties cannot be obtained.
  • the upper limit of the weight average molecular weight (Mw) is not particularly limited.
  • the weight average molecular weight (Mw) may be 5,000,000 or less, may be 4,500,000 or less, or may be 4,000,000 or less.
  • the number of arm portions present in the star-shaped polymer corresponds to the number of polymerization initiation groups capable of serving as initiation points in the CD skeleton-containing compound.
  • the number of arm portions is up to 21 in the case of the CD skeleton-containing compound of the formula (1) described hereinabove.
  • the number of arm portions in the star-shaped polymer is not particularly limited, but is preferably 4 or more for the reason that excellent mechanical strength is obtained, and is more preferably 7 or more, still more preferably 10 or more, and particularly preferably 15 or more.
  • the number of arm portions in the star-shaped polymer is preferably 24 or less in order to prevent gelation.
  • the star-shaped polymer according to the present invention is obtained by a production method described later.
  • the star-shaped polymer according to the present invention is preferably produced by controlled radical (living radical) polymerization.
  • the star-shaped polymer according to the present invention is preferably produced by ATRP (atom transfer radical polymerization) or RAFT polymerization (reversible addition/fragmentation chain transfer polymerization) .
  • the controlled radical (living radical) polymerization such as ATRP or RAFT polymerization proceeds linearly while preventing the recombination of growing radicals or disproportionation, and can precisely synthesize a polymer having a narrow molecular weight distribution.
  • the tip of the arm portion of the star-shaped polymer has a polymerization initiation terminal formed by living radical polymerization.
  • the tip of the arm portion has a residue after radical cleavage of an organic halogen compound.
  • the tip of the arm portion has a residue after thermal cleavage of a radical polymerization initiator, or a residue after cleavage of a chain transfer agent.
  • the "polymerization initiation terminal formed by living radical polymerization” may be an initiation terminal of a polymer chain resulting from a growth reaction that is triggered by a radical generated by thermal cleavage of a radical polymerization initiator, or may be an initiation terminal of a polymer chain resulting from a growth reaction that is triggered by a radical generated by cleavage of a chain transfer agent.
  • the method for producing a star-shaped polymer according to the present invention is characterized in that a star-shaped polymer is obtained by performing living radical polymerization while using a CD skeleton-containing compound as an initiator in such a manner that a monofunctional vinyl compound as a first block constituent component is polymerized beforehand to form an intermediate polymer as a macroinitiator, and further a monofunctional vinyl compound as a second block constituent component is polymerized to form a second block.
  • the production method according to the present invention allows for easy controlling of the monomer conversion ratios of the monofunctional vinyl compounds that form the respective blocks, and can prevent the occurrence of gelation by coupling of the star-shaped polymer molecules.
  • the production method will be described in detail below focusing on the case where the living radical polymerization is ATRP.
  • the method for producing a star-shaped polymer according to the present invention includes a step 1 of obtaining a core portion by synthesizing a CD skeleton-containing compound, a step 2 of obtaining an intermediate polymer as a macroinitiator including the core portion and a first block, and a step 3 of obtaining a star-shaped polymer including the core portion, the first block and a second block, and may further include additional steps as required.
  • a cyclodextrin, a compound containing a polymerization initiation group, and a solvent are added and mixed with one another to prepare a CD skeleton-containing compound.
  • the step 1 may be performed using a conventionally known process.
  • the CD skeleton-containing compound corresponds to the core portion of the star-shaped polymer according to the present invention.
  • the CD skeleton-containing compound may be a commercial product.
  • the step 1 may be omitted.
  • the cyclodextrin that is used may be one described in the section of the core portion of the star-shaped polymer.
  • the cyclodextrin may be ⁇ -cyclodextrin.
  • the cyclodextrins may be used singly, or two or more may be used in combination.
  • the polymerization initiation group may be one described in the section of the core portion of the star-shaped polymer.
  • the polymerization initiation group may be a 2-bromoisobutyryl group.
  • the compound containing a polymerization initiation group may be 2-bromoisobutyryl bromide.
  • the compounds containing a polymerization initiation group may be used singly, or two or more may be used in combination.
  • the number of polymerization initiation groups corresponds to the number of arms in the star-shaped polymer that will be produced.
  • the number of polymerization initiation groups is preferably determined in accordance with the number of arms in the star-shaped polymer that is to be produced.
  • the number of polymerization initiation groups serving as polymerization initiation points is 4.
  • the number of polymerization initiation groups is 21.
  • the number of polymerization initiation groups may be controlled by controlling the blending ratio of the compound containing a polymerization initiation group to the cyclodextrin.
  • the molar ratio of the amount added of the compound containing a polymerization initiation group to the amount added of the cyclodextrin may be controlled appropriately in accordance with the desired number of arms in the target star-shaped polymer.
  • the compound containing a polymerization initiation group is preferably used in a molar amount four to five times the moles of the cyclodextrin.
  • the compound containing a polymerization initiation group is preferably used in a molar amount seven to nine times the moles of the cyclodextrin.
  • the compound containing a polymerization initiation group is preferably used in a molar amount fourteen to twenty-three times the moles of the cyclodextrin.
  • the compound containing a polymerization initiation group is preferably used in a molar amount twenty-one to forty-two times the moles of the cyclodextrin.
  • the solvent is not particularly limited.
  • the solvents include hydrocarbon solvents such as hexane, octane, decane, isodecane, cyclohexane, methylcyclohexane, toluene, xylene and ethylbenzene; alcohol solvents such as methanol, ethanol, propanol, isopropanol (2-propanol) , butanol, isobutanol, hexanol, benzyl alcohol and cyclohexanol; glycol solvents such as ethylene glycol, diethylene glycol, propylene glycol, dipropylene glycol, methylcellosolve, ethylcellosolve, butylcellosolve, propylene glycol monomethyl ether, propylene glycol monoethyl ether, propylene glycol propyl ether, diglyme, triglyme, tetraglyme, dipropylene
  • a catalyst may be further mixed in order to enhance the reaction rate and the reaction yield.
  • the catalyst is preferably an organic amine.
  • the organic amines include trimethylamine, triethylamine, dimethylbutylamine, tributylamine, trioctylamine, dodecyldimethylamine, dimethylaminoethanol, triethanolamine, tripropanolamine, diazabicycloundecene, diazabicyclooctane, N-methylmorpholine, pyridine and 4-dimethylaminopyridine.
  • the catalyst is added in an amount of about 0.001 to 2 mass%relative to the mass of the monofunctional vinyl compound.
  • the reaction temperature is not particularly limited but is usually room temperature.
  • the amount of reaction time is not particularly limited but is usually 1 to 48 hours.
  • the reaction atmosphere may be air or an atmosphere of an inert gas such as nitrogen gas or argon gas.
  • the CD skeleton-containing compound that is obtained is represented by the following general formula (1) :
  • R 1 independently denotes a hydrogen atom or a 2-bromoisobutyryl group, and *denotes a bond.
  • the completion of the reaction may be easily confirmed by measurement such as thin-layer chromatography, liquid chromatography, gas chromatography or 1 H-NMR.
  • the product obtained may be isolated by a known operation such as filtration, concentration, extraction or purification.
  • a monofunctional vinyl compound as a first block constituent component is polymerized by living radical polymerization in the presence of a catalyst while using the CD skeleton-containing compound obtained in the step 1 as an initiator, and thereby an intermediate polymer is prepared that includes a core portion and a plurality of first blocks each including a structural unit derived from the monofunctional vinyl compound and bonded to the initiation point of the core portion.
  • the intermediate polymer corresponds to the core portion and the first blocks in the star-shaped polymer according to the present invention.
  • the intermediate polymer is a macroinitiator and is used in a step 3 described later.
  • the CD skeleton-containing compound, a catalyst, a ligand, a monofunctional vinyl compound and a solvent are added and mixed with one another. Subsequently, the dissolved oxygen in the system is removed by blowing nitrogen into the system, and the system is then heated to perform living radical polymerization of the monofunctional vinyl compound.
  • a single kind, or two or more kinds of monofunctional vinyl compounds may be used to form the first blocks.
  • the monofunctional vinyl compounds include the monofunctional vinyl compounds illustrated in the description of the star-shaped polymer according to the present invention.
  • the monofunctional vinyl compound may be n-butyl acrylate.
  • the solvent is not particularly limited. Examples of the solvents include the solvents illustrated in the description of the step 1.
  • the solid concentration of the monofunctional vinyl compound in the solvent is preferably 1 mass%or more, more preferably 3 mass%or more, and still more preferably 5 mass%or more.
  • the solid concentration of the monofunctional vinyl compound in the solvent is preferably 40 mass%or less, more preferably 35 mass%or less, and still more preferably 30 mass%or less.
  • the blending ratio of the CD skeleton-containing compound to the monofunctional vinyl compound is not particularly limited and is variable depending on the number of polymerization initiation groups in the CD skeleton- containing compound that is used.
  • the molar ratio (CD skeleton-containing compound: monofunctional vinyl compound) is preferably 1: 2 to 1: 7.5, and more preferably 1: 3 to 1: 7.
  • a transition metal complex may be suitably used as the catalyst.
  • catalysts include complexes of transition metals of Group 3 to Group 10, in particular, Group 8 to Group 10 in the periodic table (the long form of periodic table of 18 Groups) .
  • Specific examples of the catalysts include copper (I) chloride, copper (II) chloride, copper (I) bromide, copper (II) bromide, chloro (indenyl) bis (triphenylphosphine) ruthenium (II) (dichloromethane adduct) and chloro (indenyl) bis ( ⁇ 5-pentamethylcyclopentadiene) [bis (triphenylphosphine) ] ruthenium (II) .
  • copper (II) chloride is preferable because of excellent reactivity.
  • the ligand is used to increase the catalytic activity of the copper compound.
  • the ligands include 2, 2'-bipyridyl and derivatives thereof; 1, 10-phenanthroline and derivatives thereof; and polyamines such as tetramethylethylenediamine, pentamethyldiethylenetriamine and tris [2- (dimethylamino) ethyl] amine.
  • polyamines such as tetramethylethylenediamine, pentamethyldiethylenetriamine and tris [2- (dimethylamino) ethyl] amine.
  • tris [2- (dimethylamino) ethyl] amine is preferable.
  • the blending amounts are usually designed in molar ratio.
  • the blending ratio of the CD skeleton-containing compound to the monofunctional vinyl compound is determined based on the number of polymerization initiation groups in the CD skeleton-containing compound that is used, the design of arm length and the design of arm composition (the proportion in the arms) , and next the amount of the catalyst is determined in the catalyst/CD skeleton-containing compound molar ratio.
  • the molar ratio (catalyst/CD skeleton-containing compound) of the catalyst to the CD skeleton-containing compound is usually 0.01 to 1 mol, and good reactivity is advantageously obtained.
  • the amount of the ligand is determined based on the ligand/catalyst ratio (by mol) .
  • the molar ratio (ligand/catalyst) of the ligand to the catalyst is usually 0.5 to 10 mol, and good reactivity is advantageously obtained.
  • additives may be mixed as required in order to increase the catalytic activity.
  • the additives include Lewis acids (such as, for example, aluminum alkoxides) , inorganic salts (such as, for example, sodium carbonate and sodium benzoate) and reductants (such as, for example, tin 2-ethylhexanoate) .
  • Lewis acids such as, for example, aluminum alkoxides
  • inorganic salts such as, for example, sodium carbonate and sodium benzoate
  • reductants such as, for example, tin 2-ethylhexanoate
  • the reaction temperature is variable depending on factors such as the composition of the arm portion, and the number of arms, but is usually -50°C to 400°C, preferably 0°C to 300°C, and more preferably 40 to 250°C.
  • the amount of reaction time is usually 1 to 48 hours.
  • the reaction atmosphere may be air or an atmosphere of an inert gas such as nitrogen gas or argon gas.
  • the living radical polymerization in the step 2 is preferably carried out until the monomer conversion ratio of the monofunctional vinyl compound reaches 10%or more, more preferably 13%or more, and still more preferably 15%or more.
  • the living radical polymerization is preferably performed until the monomer conversion ratio of the monofunctional vinyl compound reaches 60%or less, more preferably 50%or less, and still more preferably 40%or less.
  • the star-shaped polymer that is obtained tends to be free from gelation.
  • the monomer conversion ratio may be calculated using gas chromatography measurement.
  • the peak area of the monomer before the start of polymerization (the initial monomer peak area) is measured using tridecane as an internal standard. After the start of polymerization, the peak area decreases with lowering of the monomer concentration.
  • the peak area of the monomer during the polymerization reaction (the monomer peak area during reaction) is measured using tridecane as an internal standard. In this manner, the monomer conversion ratio of the monofunctional vinyl compound may be calculated. Specifically, the monomer conversion ratio may be determined from the following equation.
  • the completion of the reaction may be easily confirmed by measurement such as thin-layer chromatography, liquid chromatography, gas chromatography or 1 H-NMR.
  • the product obtained may be isolated by a known operation such as filtration, concentration, extraction or purification.
  • the intermediate polymer that is produced is preferably purified after the completion of the reaction. By performing purification to remove the unreacted monofunctional vinyl compound used to form the first blocks, the living radical polymerization reaction in the step 3 described below is allowed to proceed easily.
  • a monofunctional vinyl compound as a second block constituent component is polymerized by living radical polymerization in the presence of a catalyst while using the intermediate polymer from the step 2 as a macroinitiator, and thereby a star-shaped polymer is prepared that includes a plurality of second blocks each including a structural unit derived from the monofunctional vinyl compound and bonded to the first block.
  • the intermediate polymer, a catalyst, a ligand, a monofunctional vinyl compound and a solvent are added and mixed with one another. Subsequently, the dissolved oxygen in the system is removed by blowing nitrogen into the system, and the system is then heated to perform living radical polymerization of the monofunctional vinyl compound.
  • a single kind, or two or more kinds of monofunctional vinyl compounds may be used to form the second blocks.
  • Examples of the monofunctional vinyl compounds include the monofunctional vinyl compounds illustrated in the description of the star-shaped polymer according to the present invention.
  • the monofunctional vinyl compound may be methyl methacrylate.
  • the solvent is not particularly limited. Examples of the solvents include the solvents illustrated in the description of the step 1.
  • the solid concentration of the monofunctional vinyl compound in the solvent is preferably 1 mass%or more, more preferably 3 mass%or more, and still more preferably 5 mass%or more.
  • the solid concentration of the monofunctional vinyl compound in the solvent is preferably 40 mass%or less, more preferably 35 mass%or less, and still more preferably 30 mass%or less.
  • the blending ratio of the intermediate polymer to the monofunctional vinyl compound is not particularly limited and is variable depending on the number of arms that is designed.
  • the molar ratio (intermediate polymer: monofunctional vinyl compound) is preferably 1: 3 to 1: 8, and more preferably 1: 4 to 1: 7.
  • Examples of the catalysts and of the ligands include the catalysts and the ligands illustrated in the description of the step 2.
  • the amount added of the catalyst is usually 0.01 to 1 mol per mol of the monofunctional vinyl compound, and good reactivity is advantageously obtained.
  • the amount of the ligand is determined based on the ligand/catalyst ratio (by mol) .
  • the molar ratio (ligand/catalyst) of the ligand to the catalyst is usually 0.5 to 10 mol, and good reactivity is advantageously obtained.
  • the additives illustrated in the description of the step 2 may be used as required.
  • the additives are added in an amount of, for example, about 0.001 to 2 mass%relative to the mass of the functional compound.
  • the reaction temperature is variable depending on factors such as the composition of the arm portion, and the number of arms, but is usually -50°C to 400°C, preferably 0°C to 300°C, and more preferably 40 to 250°C.
  • the amount of reaction time is usually 1 to 48 hours.
  • the reaction atmosphere may be air or an atmosphere of an inert gas such as nitrogen gas or argon gas.
  • the living radical polymerization in the step 3 is preferably carried out until the monomer conversion ratio of the monofunctional vinyl compound reaches 10%or more.
  • the living radical polymerization is preferably performed until the monomer conversion ratio of the monofunctional vinyl compound reaches 40%or less, more preferably 33%or less, and still more preferably 30%or less.
  • the star-shaped polymer that is obtained tends to be free from gelation.
  • the star-shaped polymer according to the present invention may be isolated by a known operation such as filtration, concentration, extraction or purification.
  • a paint according to the present invention includes the star-shaped polymer according to the present invention, and further includes additional components such as an organic solvent as required.
  • the content of the star-shaped polymer in the paint is not particularly limited.
  • the organic solvent is not particularly limited. Examples thereof include ketone solvents, cyclic ether solvents, ester solvents, aromatic solvents, alcohol solvents and glycol ether solvents.
  • ketone solvents examples include acetone, methyl ethyl ketone and methyl isobutyl ketone.
  • cyclic ether solvents examples include tetrahydrofuran and dioxolane.
  • ester solvents examples include methyl acetate, ethyl acetate and butyl acetate.
  • aromatic solvents examples include toluene and xylene.
  • alcohol solvents examples include methanol, isopropanol (2-propanol) and butanol.
  • glycol ether solvents examples include ethylene glycol monoethyl ether, ethylene glycol monobutyl ether, propylene glycol monomethyl ether, propylene glycol monopropyl ether and diethylene glycol monoethyl ether.
  • the organic solvents may be used singly, or two or more may be used in combination.
  • the organic solvent is used mainly to dissolve the star-shaped polymer and to control the viscosity of the paint. It is usually preferable to control the nonvolatile content to the range of 30 to 90 mass%.
  • the paint according to the present invention has a relatively low viscosity and thus the amount of the organic solvent used may be small as compared to, for example, a usual acrylic acrylate monomer having a high molecular weight.
  • the paint may contain additional components, for example, additives generally used in paints such as UV absorbers, antioxidants, silicone additives, fluorine additives, organic beads, antistatic agents, silane-coupling agents, inorganic microparticles, inorganic fillers, rheology control agents, defoaming agents, antifogging agents and colorants.
  • additives generally used in paints such as UV absorbers, antioxidants, silicone additives, fluorine additives, organic beads, antistatic agents, silane-coupling agents, inorganic microparticles, inorganic fillers, rheology control agents, defoaming agents, antifogging agents and colorants.
  • UV absorbers examples include triazine derivatives, 2- (2'-xanthenecarboxy-5'-methylphenyl) benzotriazole, 2- (2'-o-nitrobenzyloxy-5'-methylphenyl) benzotriazole, 2-xanthenecarboxy-4-dodecyloxybenzophenone and 2-o-nitrobenzyloxy-4-dodecyloxybenzophenone.
  • triazine derivatives examples include 2- [4- ⁇ (2- hydroxy-3-dodecyloxypropyl) oxy ⁇ -2-hydroxyphenyl] -4, 6-bis (2, 4-dimethylphenyl) -1, 3, 5-triazine and 2- [4- ⁇ (2-hydroxy-3-tridecyloxypropyl) oxy ⁇ -2-hydroxyphenyl] -4, 6-bis (2, 4-dimethylphenyl) -1, 3, 5-triazine.
  • antioxidants examples include hindered phenol antioxidants, hindered amine antioxidants, organic sulfur antioxidants and phosphoric acid ester antioxidants.
  • silicone additives examples include polyorganosiloxanes having an alkyl group and/or a phenyl group, polydimethylsiloxanes having a polyether-modified acrylic group, and polydimethylsiloxanes having a polyester-modified acrylic group.
  • Examples of the polyorganosiloxanes having an alkyl group and/or a phenyl group include dimethylpolysiloxane, methylphenylpolysiloxane, cyclic dimethylpolysiloxane, methylhydrogenpolysiloxane, polyether-modified dimethylpolysiloxane copolymer, polyester-modified dimethylpolysiloxane copolymer, fluorine-modified dimethylpolysiloxane copolymer and amino-modified dimethylpolysiloxane copolymer.
  • fluorine additives examples include "MEGAFACE” series manufactured by DIC Corporation.
  • organic beads examples include polymethyl methacrylate beads, polycarbonate beads, polystyrene beads, polyacrylic styrene beads, silicone beads, glass beads, acrylic beads, benzoguanamine resin beads, melamine resin beads, polyolefin resin beads, polyester resin beads, polyamide resin beads, polyimide resin beads, polyfluoroethylene resin beads and polyethylene resin beads.
  • the average particle diameter of these organic beads is preferably in the range of 1 to 10 ⁇ m.
  • antistatic agents examples include pyridinium, imidazolium, phosphonium, ammonium or lithium salts of bis (trifluoromethanesulfonyl) imide or bis (fluorosulfonyl) imide.
  • the paint according to the present invention may further include additional components such as resins, and organic or inorganic particles in order to control the viscosity or the refractive index, to control the tone of a coating, and to control other paint properties and coating properties.
  • additional components such as resins, and organic or inorganic particles in order to control the viscosity or the refractive index, to control the tone of a coating, and to control other paint properties and coating properties.
  • the resins include acrylic resins, phenolic resins, polyester resins, polystyrene resins, urethane resins, urea resins, melamine resins, alkyd resins, epoxy resins, polyamide resins, polycarbonate resins, petroleum resins and fluororesins.
  • organic or inorganic particles examples include polytetrafluoroethylene (PTFE) , polyethylene, polypropylene, carbon, titanium oxide, alumina, copper and silica microparticles.
  • PTFE polytetrafluoroethylene
  • the paint according to the present invention may be produced by any method without limitation.
  • the paint may be obtained by mixing the star-shaped polymer, the organic solvent, and optionally other components such as additives and resins.
  • a coating according to the present invention is formed from the paint according to the present invention.
  • the coating is obtained in such a manner that after stirring of the paint containing components such as the star-shaped polymer and the organic solvent, the paint is applied onto a substrate such as a PET film, and the wet film is dried by heating.
  • the coating according to the present invention may be used in any applications without limitation, but is useful as a coating in a hard coat film. Furthermore, the coating according to the present invention is expected to be applied to soft electronics materials (such as organic thin-film solar cells, wearables and battery electrolytes) , self-repairing materials, surface modifiers, and improvements in functionality of existing polymer products (such as coating UV resins, IJ printer ink binder resins and optical resins) .
  • soft electronics materials such as organic thin-film solar cells, wearables and battery electrolytes
  • self-repairing materials such as coating UV resins, IJ printer ink binder resins and optical resins
  • the GPC (RI) number average molecular weight (Mn) may be determined by the following GPC (RI) measurement method.
  • Measurement device High-performance GPC device ( "HLC-8220GPC” manufactured by Tosoh Corporation)
  • RI differential refractometer
  • the arm length of a star-shaped polymer was calculated from the following equation.
  • a sample weighing 0.1 g was sampled from the polymerization liquid with a syringe before the start of polymerization, was diluted with 2 g of tetrahydrofuran containing 2,000 ppm of tridecane as an internal standard, and was analyzed by gas chromatography. Next, a sample weighing 0.1 g was sampled during the polymerization reaction, was similarly diluted with 2 g of tetrahydrofuran containing tridecane, and was analyzed by gas chromatography. Based on the measured values, the monomer conversion ratio was calculated from the following equation.
  • ⁇ -Cyclodextrin (hereinafter, abbreviated as ⁇ -CD) (3.41 g, 3 mmol, used after vacuum dried at 80°C for 1 hour) was dissolved into 30 ml of anhydrous 1-methyl-2-pyrrolidione (hereinafter, abbreviated as NMP) .
  • NMP anhydrous 1-methyl-2-pyrrolidione
  • DMAP 4- (N, N-dimethylamino) pyridine
  • 2-bromoisobutyryl bromide 29.0 ml, 126 mmol was dissolved into anhydrous NMP (15 ml) , and the resultant solution was added dropwise to the ⁇ -CD solution held at 0°C while performing stirring with a magnetic stirrer. The reaction temperature was maintained at 0°C for 2 hours, and was subsequently increased gradually to ambient. Thereafter, the reaction was continued for 1 day.
  • the amount added of 2-bromoisobutyryl bromide was twice the amount required.
  • the reaction liquid was diluted with 50 ml of dichloromethane, and was sequentially washed with a saturated aqueous NaHCO 3 solution (100 ml, twice) , an aqueous NaCl solution (100 ml, twice) and water (100 ml, twice) .
  • the resultant solution was dropped to n-hexane to form a brown deposit.
  • the deposit was filtered, washed with hexane twice, and vacuum dried at 40°C to give a CD skeleton-containing compound 21Br- ⁇ -CD having 21 bromo groups as initiation points.
  • bromo groups were confirmed by 1 H-NMR, specifically, by comparing the integrals of signals assigned to methyl protons (about 1.88 ppm) in the initiation groups -OCO-C (CH 3 ) . Furthermore, the introduction was also confirmed based on the attenuation of the signal assigned to the 1-position protons in ⁇ -CD observed at 4.80-5.50 ppm.
  • n-butyl acrylate (hereinafter, abbreviated as BA) was added in an amount (26.24 g, 0.205 mol) 5 times greater than the required amount in order to prevent star coupling, and anisole solvent (50 g) was subsequently added.
  • the mixture was bubbled with N 2 at 100 mL/min for 1 hour to remove oxygen in the system.
  • tin 2-ethylhexanoate Sn (EH) 2 reductant (0.1404 g, 0.347 mmol) was added with a syringe to the flask in a nitrogen gas atmosphere to reduce the Cu catalyst complex, thereby initiating polymerization.
  • Initiator/CuCl 2 /Me6TREN/Sn (EH) 2 1/0.63/2.52/6.93 (by mol) .
  • the amount of BA, increased by 5 times, may be counted as an amount of solvent, and thus the solid concentration in the reaction liquid is calculated to be about 7%.
  • the flask was tightly closed with a glass stopper and was soaked in an oil bath that had been set at 60°C, and the polymerization continued.
  • the monomer conversion ratio and the molecular weight of the polymer were measured by GC measurement and GPC measurement, respectively.
  • the temperature was lowered and air was injected into the system to terminate the polymerization.
  • the polymer solution was transferred to a beaker soaked in an ice bath. Next, methanol was continuously dropped to the beaker while performing stirring until the solution became clouded, and a deposit was obtained. The dropping was stopped, and the solution was allowed to stand for a predetermined amount of time and was filtered to remove the liquid.
  • an intermediate polymer 21Star-PBA was obtained that had an arm length of about 5,000 and an arm composition of BA.
  • An intermediate polymer 21Star-PBA having an arm length of about 6,000 and an arm composition of BA was prepared by the same method as Intermediate Polymer Synthesis Example 1, except that the BA monomer was added in an amount (31.50 g, 0.246 mol) 5 times greater than the required amount in order to prevent star coupling.
  • the amount of BA, increased by 5 times, may be counted as an amount of solvent, and thus the solid concentration in the reaction liquid is calculated to be about 8%.
  • the temperature was lowered and air was injected into the system to terminate the polymerization.
  • the polymer solution was transferred to a beaker soaked in an ice bath.
  • the flask was tightly closed with a glass stopper and was soaked in an oil bath that had been set at 60°C, and the polymerization continued.
  • the monomer conversion ratio and the molecular weight of the polymer were measured by GC measurement and GPC measurement, respectively.
  • the temperature was lowered and air was injected into the system to terminate the polymerization.
  • the polymer solution was transferred to a beaker soaked in an ice bath. Next, methanol was continuously dropped to the beaker while performing stirring until the solution became clouded, and a deposit was obtained. The dropping was stopped, and the solution was allowed to stand for a predetermined amount of time and was filtered to remove the liquid.
  • an intermediate polymer 4 Star-PBA was obtained that had the number of arms of 4, an arm length of about 6,000 and an arm composition of BA.
  • the flask was tightly closed with a glass stopper and was soaked in an oil bath that had been set at 60°C, and the polymerization continued.
  • the monomer conversion ratio and the molecular weight of the polymer were measured by GC measurement and GPC measurement, respectively.
  • the temperature was lowered and air was injected into the system to terminate the polymerization.
  • the polymer solution was transferred to a beaker soaked in an ice bath. Next, methanol was continuously dropped to the beaker while performing stirring until the solution became clouded, and a deposit was obtained. The dropping was stopped, and the solution was allowed to stand for a predetermined amount of time and was filtered to remove the liquid.
  • an intermediate polymer 7Star-PBA was obtained that had the number of arms of 7, an arm length of about 6,000 and an arm composition of BA.
  • the flask was tightly closed with a glass stopper and was soaked in an oil bath that had been set at 60°C, and the polymerization continued.
  • the monomer conversion ratio and the molecular weight of the polymer were measured by GC measurement and GPC measurement, respectively.
  • the temperature was lowered and air was injected into the system to terminate the polymerization.
  • the polymer solution was transferred to a beaker soaked in an ice bath. Next, methanol was continuously dropped to the beaker while performing stirring until the solution became clouded, and a deposit was obtained. The dropping was stopped, and the solution was allowed to stand for a predetermined amount of time and was filtered to remove the liquid.
  • an intermediate polymer 14Star-PBA was obtained that had the number of arms of 14, an arm length of about 6,000 and an arm composition of BA.
  • the flask was tightly closed with a glass stopper and was soaked in an oil bath that had been set at 60°C, and the polymerization continued.
  • the monomer conversion ratio and the molecular weight of the polymer were measured by GC measurement and GPC measurement, respectively.
  • the temperature was lowered and air was injected into the system to terminate the polymerization.
  • the polymer solution was transferred to a beaker soaked in an ice bath. Next, methanol was continuously dropped to the beaker while performing stirring until the solution became clouded, and a deposit was obtained. The dropping was stopped, and the solution was allowed to stand for a predetermined amount of time and was filtered to remove the liquid.
  • an intermediate polymer 14Star-PBA was obtained that had the number of arms of 14, an arm length of about 5,000 and an arm composition of BA.
  • the flask was tightly closed with a glass stopper and was soaked in an oil bath that had been set at 60°C, and the polymerization continued.
  • the monomer conversion ratio and the molecular weight of the polymer were measured by GC measurement and GPC measurement, respectively.
  • the temperature was lowered and air was injected into the system to terminate the polymerization.
  • the polymer solution was transferred to a beaker soaked in an ice bath. Next, methanol was continuously dropped to the beaker while performing stirring until the solution became clouded, and a deposit was obtained. The dropping was stopped, and the solution was allowed to stand for a predetermined amount of time and was filtered to remove the liquid.
  • an intermediate polymer 14 Star-PBA was obtained that had the number of arms of 14, an arm length of about 7, 500 and an arm composition of BA.
  • the flask was tightly closed with a glass stopper and was soaked in an oil bath that had been set at 60°C, and the polymerization continued.
  • the monomer conversion ratio and the molecular weight of the polymer were measured by GC measurement and GPC measurement, respectively.
  • the temperature was lowered and air was injected into the system to terminate the polymerization.
  • the polymer solution was transferred to a beaker soaked in an ice bath. Next, methanol was continuously dropped to the beaker while performing stirring until the solution became clouded, and a deposit was obtained. The dropping was stopped, and the solution was allowed to stand for a predetermined amount of time and was filtered to remove the liquid. Thus, an intermediate polymer 14Star-PBA was obtained that had the number of arms of 14, an arm length of about 10,000 and an arm composition of BA.
  • MMA methyl methacrylate
  • the polymer solution was transferred to a beaker soaked in an ice bath. Next, methanol was continuously dropped to the beaker while performing stirring until the solution became clouded, and a deposit was obtained. The dropping was stopped, and the solution was allowed to stand for a predetermined amount of time and was filtered to remove the liquid.
  • the molecular weight of the star-shaped polymer obtained was measured to be 185, 269. Because the number of initiation groups was 21, the arm length was calculated to be 8822.
  • the star-shaped polymer obtained had an arm length close to the design (the designed arm length) .
  • Fig. 1 illustrates GPC charts of 21Br- ⁇ -CD obtained in Initiator Preparation Example 1, Star-PBA obtained in Intermediate Polymer Preparation Example 1, and Star-PBA-PMMA obtained in Example 1.
  • the star-shaped polymer Star-PBA-PMMA of Example 1 had a unimodal peak, indicating that the star-shaped polymer was free from coupled stars.
  • the polymer solution was transferred to a beaker soaked in an ice bath. Next, methanol was continuously dropped to the beaker while performing stirring until the solution became clouded, and a deposit was obtained. The dropping was stopped, and the solution was allowed to stand for a predetermined amount of time and was filtered to remove the liquid.
  • the molecular weight of the star-shaped polymer obtained was measured to be 194, 783. Because the number of initiation groups was 21, the arm length was calculated to be 9,275. The star-shaped polymer obtained had an arm length close to the design.
  • the star-shaped polymer Star-PBA-PMMA obtained in Example 2 was analyzed by GPC.
  • Fig. 2 illustrates GPC charts of 21Br- ⁇ -CD obtained in Initiator Preparation Example 1, Star-PBA obtained in Intermediate Polymer Preparation Example 2, and Star-PBA-PMMA obtained in Example 2.
  • the star-shaped polymer Star-PBA-PMMA of Example 2 had a unimodal peak, indicating that the star-shaped polymer was free from coupled stars.
  • the polymer solution was transferred to a beaker soaked in an ice bath. Next, methanol was continuously dropped to the beaker while performing stirring until the solution became clouded, and a deposit was obtained. The dropping was stopped, and the solution was allowed to stand for a predetermined amount of time and was filtered to remove the liquid.
  • the molecular weight of the star-shaped polymer obtained was measured to be 54, 516. Because the number of initiation groups was 4, the arm length was calculated to be 13,629. The star-shaped polymer obtained had an arm length close to the design.
  • the star-shaped polymer Star-PBA-PMMA obtained in Example 3 was analyzed by GPC.
  • Fig. 3 illustrates GPC charts of 4Br- ⁇ -CD obtained in Initiator Preparation Example 2, Star-PBA obtained in Intermediate Polymer Preparation Example 3, and Star-PBA-PMMA obtained in Example 3.
  • the star-shaped polymer Star-PBA-PMMA of Example 3 had a unimodal peak, indicating that the star-shaped polymer was free from coupled stars.
  • the polymer solution was transferred to a beaker soaked in an ice bath. Next, methanol was continuously dropped to the beaker while performing stirring until the solution became clouded, and a deposit was obtained. The dropping was stopped, and the solution was allowed to stand for a predetermined amount of time and was filtered to remove the liquid.
  • the molecular weight of the star-shaped polymer obtained was measured to be 71, 340. Because the number of initiation groups was 7, the arm length was calculated to be 10,191. The star-shaped polymer obtained had an arm length close to the design.
  • the star-shaped polymer Star-PBA-PMMA obtained in Example 4 was analyzed by GPC.
  • Fig. 4 illustrates GPC charts of 7Br- ⁇ -CD obtained in Initiator Preparation Example 3, Star-PBA obtained in Intermediate Polymer Preparation Example 4, and Star-PBA-PMMA obtained in Example 4.
  • the star-shaped polymer Star-PBA-PMMA of Example 4 had a unimodal peak, indicating that the star-shaped polymer was free from coupled stars.
  • the polymer solution was transferred to a beaker soaked in an ice bath. Next, methanol was continuously dropped to the beaker while performing stirring until the solution became clouded, and a deposit was obtained. The dropping was stopped, and the solution was allowed to stand for a predetermined amount of time and was filtered to remove the liquid.
  • the molecular weight of the star-shaped polymer obtained was measured to be 118, 548. Because the number of initiation groups was 14, the arm length was calculated to be 8,468. The star-shaped polymer obtained had an arm length close to the design.
  • Fig. 5 illustrates GPC charts of 14Br- ⁇ -CD obtained in Initiator Preparation Example 4, Star-PBA obtained in Intermediate Polymer Preparation Example 5, and Star-PBA-PMMA obtained in Example 5.
  • the star-shaped polymer Star-PBA-PMMA of Example 5 had a unimodal peak, indicating that the star-shaped polymer was free from coupled stars.
  • the polymer solution was transferred to a beaker soaked in an ice bath. Next, methanol was continuously dropped to the beaker while performing stirring until the solution became clouded, and a deposit was obtained. The dropping was stopped, and the solution was allowed to stand for a predetermined amount of time and was filtered to remove the liquid.
  • the molecular weight of the star-shaped polymer obtained was measured to be 102, 617. Because the number of initiation groups was 14, the arm length was calculated to be 7, 329. The star-shaped polymer obtained had an arm length close to the design.
  • the star-shaped polymer Star-PBA-PMMA obtained in Example 6 was analyzed by GPC.
  • Fig. 6 illustrates GPC charts of 14Br- ⁇ -CD obtained in Initiator Preparation Example 4, Star-PBA obtained in Intermediate Polymer Preparation Example 6, and Star-PBA-PMMA obtained in Example 6.
  • the star-shaped polymer Star-PBA-PMMA of Example 6 had a unimodal peak, indicating that the star-shaped polymer was free from coupled stars.
  • the polymer solution was transferred to a beaker soaked in an ice bath. Next, methanol was continuously dropped to the beaker while performing stirring until the solution became clouded, and a deposit was obtained. The dropping was stopped, and the solution was allowed to stand for a predetermined amount of time and was filtered to remove the liquid.
  • the molecular weight of the star-shaped polymer obtained was measured to be 165, 687. Because the number of initiation groups was 14, the arm length was calculated to be 11,834. The star-shaped polymer obtained had an arm length close to the design.
  • Fig. 7 illustrates GPC charts of 14Br- ⁇ -CD obtained in Initiator Preparation Example 4, Star-PBA obtained in Intermediate Polymer Preparation Example 7, and Star-PBA-PMMA obtained in Example 7.
  • the high-molecular region indicated the presence of slight star coupling in the star-shaped polymer Star-PBA-PMMA of Example 7, but the amount of coupled stars in the star-shaped polymer was very small.
  • the polymer solution was transferred to a beaker soaked in an ice bath. Next, methanol was continuously dropped to the beaker while performing stirring until the solution became clouded, and a deposit was obtained. The dropping was stopped, and the solution was allowed to stand for a predetermined amount of time and was filtered to remove the liquid.
  • the molecular weight of the star-shaped polymer obtained was measured to be 223, 139. Because the number of initiation groups was 14, the arm length was calculated to be 15,939. The star-shaped polymer obtained had an arm length close to the design.
  • Fig. 8 illustrates GPC charts of 14Br- ⁇ -CD obtained in Initiator Preparation Example 4, Star-PBA obtained in Intermediate Polymer Preparation Example 8, and Star-PBA-PMMA obtained in Example 8.
  • the high-molecular region indicated the presence of slight star coupling in the star-shaped polymer Star-PBA-PMMA of Example 8, but the amount of coupled stars in the star-shaped polymer was very small.
  • the flask was tightly closed with a glass stopper and was soaked in an oil bath that had been set at 80°C, and the polymerization continued.
  • the monomer conversion ratio and the molecular weight of the polymer were measured by GC measurement and GPC measurement, respectively.
  • the reaction was continued for 11 hours until the BA conversion ratio reached nearly 100%.
  • MMA was added in a required amount of 14 g to the flask. Furthermore, anisole was added to control the solid concentration to 20%. The reaction was continued at 70°C for 11 hours until the MMA conversion ratio reached nearly 100%.
  • the polymer solution was transferred to a beaker soaked in an ice bath. Next, methanol was continuously dropped to the beaker while performing stirring until the solution became clouded, and a deposit was obtained. The dropping was stopped, and the solution was allowed to stand for a predetermined amount of time and was filtered to remove the liquid, thereby recovering a polymer. A star-shaped polymer Star-PBA-PMMA of Comparative Example 1 was thus obtained.
  • FIG. 9 illustrates GPC charts of 14Br- ⁇ -CD obtained in Initiator Preparation Example 4, 14 Star-PBA before the addition of MMA, and Star-PBA-PMMA obtained in Comparative Example 1.
  • the star-shaped polymer Star-PBA-PMMA of Comparative Example 1 had bimodal peak, indicating a significant occurrence of star coupling.
  • the GPC molecular weights and the arm lengths of the star-shaped polymer obtained are described in Table 1. The arm lengths calculated from the molecular weight of each of the bimodal distribution were far different from the designed arm length of 20,000.
  • tin 2-ethylhexanoate reductant Sn (EH) 2 was added in the same amount as in Comparative Example 1 with a syringe to the flask in a nitrogen gas atmosphere to reduce the Cu catalyst complex, thereby initiating polymerization.
  • Initiator/CuCl 2 /Me6TREN/Sn (EH) 2 1/0.48/21.44/4.8 (by mol) .
  • the amount of BA increased by 1.6 times, may be counted as an amount of solvent, and thus the solid concentration in the reaction liquid is calculated to be about 10%.
  • the flask was tightly closed with a glass stopper and was soaked in an oil bath that had been set at 70°C, and the polymerization continued.
  • the monomer conversion ratio and the molecular weight of the polymer were measured by GC measurement and GPC measurement, respectively.
  • the reaction was continued for 3 hours until the BA conversion ratio reached 62%.
  • Fig. 10 illustrates a GPC chart of Star-PBA obtained in Reference Example 1. As illustrated in Fig. 10, the star-shaped polymer Star-PBA of Reference Example 1 had bimodal peak, indicating a significant occurrence of star coupling.
  • Star-PMMA obtained in Reference Example 2 was analyzed by GPC.
  • Fig. 11 illustrates a GPC chart of Star-PMMA obtained in Reference Example 2.
  • the star-shaped polymer Star-PMMA of Reference Example 2 had a broad distribution, indicating an occurrence of star coupling.
  • the star-shaped polymers obtained in Examples and Comparative Example were each adjusted to a solid concentration of 15 mass%. 6.0 g of the 15 mass%solution of the star-shaped polymer was uniformly poured to a PFA Petri dish having a diameter of 10 cm, and was dried at 120°C to form a 0.1 mm thick film. The film obtained was cut to give a test piece having a width of 5 mm and a length of 5 cm. The maximum point stress and the elongation were measured by evaluating tensile characteristics with a tensile tester (TENSILON RTG1310, manufactured by A&D Company, Limited) . The results are described in Table 1. The results of the tensile test of Examples 2 to 5 are illustrated in Fig. 12, and the results of the tensile test of Examples 6 to 8 are illustrated in Fig. 13.

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Abstract

A method for producing a star-shaped polymer including a core portion and an arm portion includes a step of preparing an intermediate polymer by performing living radical polymerization of a monofunctional vinyl compound in the presence of a catalyst while using as an initiator a cyclodextrin skeleton-containing compound having polymerization initiation groups serving as initiation points for polymerization, to prepare an intermediate polymer including a core portion and a plurality of first blocks each including a structural unit derived from the monofunctional vinyl compound and bonded to an initiation point of the core portion; and a step of preparing a star-shaped polymer by performing living radical polymerization of a monofunctional vinyl compound as a second block constituent component in the presence of a catalyst while using the intermediate polymer as a macroinitiator, to prepare a star-shaped polymer including a plurality of second blocks each including a structural unit derived from the monofunctional vinyl compound.

Description

STAR-SHAPED POLYMER, PAINT, COATING, AND METHOD FOR PRODUCING STAR-SHAPED POLYMER Technical Field
The present invention relates to a star-shaped polymer, a paint, a coating, and a method for producing a star-shaped polymer.
Background Art
It is known that base polymers having a higher molecular weight are more preferable in terms of properties such as heat resistance in various applications of polymers. However, the conventional approach of increasing the molecular weight of a linear polymer to a larger molecular structure results in a high viscosity of the polymer solution and consequently causes problems, such as difficulty in application of the polymer solution, encountered when the polymer is being used.
One of the solutions to such a problem is star-shaped polymers, which are currently under development (for example, PTL 1 and PTL 2) .
As a method for preparing a star-shaped polymer, a  method (a core first method) is known in which a star-shaped polymer is obtained by performing polymerization reaction using an initiator having a plurality of initiation points. In this method, however, it is difficult to increase the number of initiation points. While some studies have reported that a star-shaped polymer having 10 or more arms is produced using a core compound having a partial cyclodextrin skeleton (see, for example, NPL 1 and NPL 2) , increasing the number of arms raises the risk of gelation and makes industrial production difficult. For, in particular, star-shaped polymers in which the arms are composed of a polymer of blocks having different compositions from one another, the disclosure is limited to, for example, production methods using a photoinitiator, and small-scale special production methods using a coupling technique.
Citation List
Patent Literature
PTL 1: Japanese Unexamined Patent Application Publication No. 2005-240048
PTL 2: Japanese Unexamined Patent Application Publication No. H11-116606
Non Patent Literature
NPL 1: Xiuzhe Yin et al., European Polymer Journal 126 (2020) 109557.
NPL 2: F. J. Xu et al., Biomacromolecules, Vol. 10, No. 2, (2009) 285-293.
Summary of Invention
Technical Problem
Despite the fact that excellent functionality is expected, very few studies have investigated properties of coatings and other products of star-shaped polymers due to the reasons described above.
Furthermore, there have been demands for a star-shaped polymer production method capable of easily producing a star-shaped polymer having a desired number of arms while preventing the occurrence of gelation.
An object of the present invention is to provide a star-shaped polymer capable of giving a coating with excellent mechanical properties, a paint containing the star-shaped polymer, a coating having excellent mechanical properties, and a star-shaped polymer production method capable of producing the star-shaped polymer described above. Solution to Problem
The present inventors carried out extensive studies  directed to achieving the above object, and have consequently found that the object can be achieved by a star-shaped polymer that is obtained by performing living radical polymerization while using a cyclodextrin skeleton-containing compound as an initiator in such a manner that a monofunctional vinyl compound as a first block constituent component is polymerized beforehand to form an intermediate polymer as a macroinitiator, and further a monofunctional vinyl compound as a second block constituent component is polymerized to form a second block. The present invention has been completed based on the finding.
Specifically, aspects of the present invention include the following:
[1] A method for producing a star-shaped polymer, the star-shaped polymer including
a core portion, and
an arm portion being a polymer chain bonded to the core portion, the arm portion including a first block and a second block, the first block being located on a side of the polymer chain adjacent to the core portion and bonded to the core portion, the second block being located on a tip side of the polymer chain, the method including:
a step of preparing an intermediate polymer by performing living radical polymerization of a monofunctional  vinyl compound as a first block constituent component in the presence of a catalyst while using as an initiator a cyclodextrin skeleton-containing compound having polymerization initiation groups serving as initiation points for polymerization, to prepare an intermediate polymer including the core portion and a plurality of the first blocks each including a structural unit derived from the monofunctional vinyl compound and bonded to an initiation point of the core portion; and
a step of preparing a star-shaped polymer by performing living radical polymerization of a monofunctional vinyl compound as a second block constituent component in the presence of a catalyst while using the intermediate polymer as a macroinitiator, to prepare a star-shaped polymer including the core portion, the first blocks, and a plurality of the second blocks each including a structural unit derived from the monofunctional vinyl compound and bonded to the first block.
[2] The method for producing a star-shaped polymer described in [1] , in which the star-shaped polymer has 4 or more and 21 or less arm portions.
[3] The method for producing a star-shaped polymer described in [1] or [2] , in which in the step of preparing an intermediate polymer, the living radical polymerization is performed until the monomer conversion ratio of the  monofunctional vinyl compound as the first block constituent component reaches 10%or more and 60%or less.
[4] The method for producing a star-shaped polymer described in any of [1] to [3] , in which in the step of preparing a star-shaped polymer, the living radical polymerization is performed until the monomer conversion ratio of the monofunctional vinyl compound as the second block constituent component reaches 10%or more and 40%or less.
[5] The method for producing a star-shaped polymer described in any of [1] to [4] , in which the living radical polymerization in the step of preparing an intermediate polymer and in the step of preparing a star-shaped polymer is atom transfer radical polymerization.
[6] The method for producing a star-shaped polymer described in any of [1] to [5] , in which the monofunctional vinyl compound as the first block constituent component is a (meth) acrylic acid compound, and
the monofunctional vinyl compound as the second block constituent component is a (meth) acrylic acid compound.
[7] The method for producing a star-shaped polymer described in any of [1] to [6] , in which the mass ratio of the first block to the second block (first block: second block) is 30: 70 to 70: 30.
[8] The method for producing a star-shaped polymer  described in any of [1] to [7] , in which the polymerization initiation groups are α-haloacyloxy groups or α-haloacyl groups.
[9] The method for producing a star-shaped polymer described in any of [1] to [8] , in which the cyclodextrin skeleton-containing compound is a compound represented by the following formula (1) :
[Chem. 1]
Figure PCTCN2022107909-appb-000001
where R 1 independently denotes a hydrogen atom or a 2-bromoisobutyryl group, and *denotes a bond.
[10] A star-shaped polymer produced by the method for producing a star-shaped polymer described in any of [1] to [9] .
[11] A paint containing the star-shaped polymer described in [10] .
[12] A coating formed from the paint described in [11] . Advantageous Effects of Invention
The star-shaped polymer provided according to the present invention can give a coating having excellent mechanical properties.
Furthermore, the paint provided according to the present invention contains the star-shaped polymer.
Furthermore, the coating provided according to the present invention has excellent mechanical properties.
Brief Description of Drawings
Fig. 1 is a GPC chart of a star-shaped polymer prepared in Example 1.
Fig. 2 is a GPC chart of a star-shaped polymer prepared in Example 2.
Fig. 3 is a GPC chart of a star-shaped polymer prepared in Example 3.
Fig. 4 is a GPC chart of a star-shaped polymer prepared in Example 4.
Fig. 5 is a GPC chart of a star-shaped polymer prepared in Example 5.
Fig. 6 is a GPC chart of a star-shaped polymer prepared in Example 6.
Fig. 7 is a GPC chart of a star-shaped polymer prepared in Example 7.
Fig. 8 is a GPC chart of a star-shaped polymer prepared in Example 8.
Fig. 9 is a GPC chart of a star-shaped polymer prepared in Comparative Example 1.
Fig. 10 is a GPC chart of a star-shaped polymer prepared in Reference Example 1.
Fig. 11 is a GPC chart of a star-shaped polymer prepared in Reference Example 2.
Fig. 12 is a diagram illustrating tensile test results of the star-shaped polymers prepared in Examples 2 to 5.
Fig. 13 is a diagram illustrating tensile test results of the star-shaped polymers prepared in Examples 6 to 8.
Description of Embodiments
Hereinafter, a star-shaped polymer, a coating, a paint, and a method for producing a star-shaped polymer according to the present invention will be described in detail. The configurations described hereinafter are only illustrative of some embodiments of the present invention and do not limit the scope of the present invention to the contents described.
In the following description, the word " (meth) acryl" indicates both acryl and methacryl.
(Star-shaped polymer)
A star-shaped polymer according to the present invention includes a core portion and an arm portion.
The arm portion is bonded to the core portion.
In the star-shaped polymer, a plurality of arm portions are usually bonded to the core portion. For example, the arm portions extend radially from the core portion.
<Core portion>
The core portion includes a cyclodextrin skeleton-containing compound (hereinafter, sometimes abbreviated as the CD skeleton-containing compound) as a constituent component.
The CD skeleton-containing compound according to the present invention is characterized in that the hydroxy groups present in the cyclodextrin are partially or completely substituted with a compound that has a polymerization initiation group capable of serving as an initiation point for living radical polymerization. Specifically, the CD skeleton-containing compound is a cyclodextrin derivative that has a polymerization initiation group capable of serving as an initiation point for living radical polymerization at an end. With this configuration, a star-shaped polymer having a desired number of arms may be produced easily.
The cyclodextrins are a type of cyclic oligosaccharides having a cyclic structure of D-glucose molecules joined by  α- (1→4) glucoside bonds. Examples thereof include α-cyclodextrin formed by bonding of six D-glucose molecules, β-cyclodextrin formed by bonding of seven D-glucose molecules, and γ-cyclodextrin formed by bonding of eight D-glucose molecules. Among these cyclodextrins, β-cyclodextrin formed by bonding of seven D-glucose molecules is preferable because β-cyclodextrin has excellent reactivity with a compound having a polymerization initiation group and has excellent stability.
The polymerization initiation group is not particularly limited and may be any functional group capable of serving as an initiation point for living radical polymerization.
Examples of the polymerization initiation groups include azo group (-N=N +) -containing groups such as azoalkyl groups, peroxide group-containing groups such as peroxyalkyl groups, iodine atom-containing groups such as alkyl iodide groups, thiocarbonylthio group-containing groups for initiating reversible addition-elimination chain transfer polymerization reaction such as phenylthiocarbonylthiomethylphenyl group, and atom transfer radical polymerization initiation groups such as α-haloacyloxy groups, α-haloacyl groups, halosulfonyl groups and α-halobenzyl groups. Among these polymerization initiation groups, α-haloacyloxy groups, α-haloacyl groups  and halosulfonyl groups are preferable because of their excellent reactivity, and α-haloacyloxy groups and α-haloacyl groups are more preferable.
Examples of the halogen atoms contained independently in each of the α-haloacyloxy groups, the α-haloacyl groups and the halosulfonyl groups include chlorine atom, bromine atom and iodine atom, with chlorine atom and bromine atom being preferable from the point of view of reactivity.
Examples of the α-haloacyloxy groups include 2-chloroisobutyryloxy group, 2-bromoisobutyryloxy group, 2-iodoisobutyryloxy group, 2-chlorobutyryloxy group, 2-bromobutyryloxy group, 2-iodobutyryloxy group, 2-chloropropionyloxy group, 2-bromopropionyloxy group, 2-iodopropionyloxy group, chlorophenylacetoxy group, bromophenylacetoxy group and iodophenylacetoxy group.
Examples of the α-haloacyl groups include 2-chloroisobutyryl group, 2-bromoisobutyryl group, 2-iodoisobutyryl group, 2-chlorobutyryl group, 2-bromobutyryl group, 2-iodobutyryl group, 2-chloropropionyl group, 2-bromopropionyl group, 2-iodopropionyl group, dichloroacetyl group, dibromoacetyl group and diiodoacetyl group. In particular, 2-chloroisobutyryl group and 2-bromoisobutyryl  group are preferable because of their excellent polymerization initiation properties, and 2-bromoisobutyryl group is more preferable.
For example, a linking group may be present between the hydroxy group in the cyclodextrin, and the polymerization initiation group. Examples of the linking groups include C 1-C 20 alkylene groups such as methylene group, ethylene group, trimethylene group, tetramethylene group, hexamethylene group, decamethylene group and dodecamethylene group, derivative of these groups, -O-group and -S-group. When such a linking group is present, a C 2-C 10 alkylene group is preferable as the linking group because excellent reactivity is obtained.
The number of polymerization initiation groups present in the CD skeleton-containing compound is not particularly limited. The hydroxy groups in the cyclodextrin may be completely or partially substituted with the polymerization initiation groups. For example, the number of polymerization initiation groups is preferably 4 or more, more preferably 7 or more, and still more preferably 14 or more.
For example, a preferred example of the CD skeleton- containing compound described above is a compound represented by the formula (1) below.
The compound represented by the formula (1) is β-cyclodextrin in which the hydroxy groups are partially or completely substituted with a 2-bromoisobutyryl group.
[Chem. 1]
Figure PCTCN2022107909-appb-000002
where R 1 independently denotes a hydrogen atom or a 2-bromoisobutyryl group, and *denotes a bond.
In the formula (1) , the number of 2-bromoisobutyryl groups is not particularly limited. The number of 2-bromoisobutyryl groups is preferably 4 or more, more preferably 7 or more, and still more preferably 14 or more. The upper limit of the number of 2-bromoisobutyryl groups in the formula (1) is 21.
<Arm portion>
The arm portion is a polymer chain. The polymer chain is usually linear.
The arm portion includes a first block located on a side of the polymer chain adjacent to the core portion and bonded to the core portion, and a second block located on a tip side of the polymer chain. Here, the term "tip side" indicates an end of the arm portion opposite from the end adjacent to the core portion.
The mass ratio of the first block to the second block (first block: second block) is not particularly limited, but from the point of view of the balance of mechanical properties, the mass ratio is preferably 5: 95 to 95: 5, more preferably 30: 70 to 70: 30, and particularly preferably 35: 65 to 55: 45.
The first block and the second block each independently include, as a constituent component, a monofunctional vinyl compound having one polymerizable vinyl group.
The first block and the second block may each independently include a single kind of a monofunctional vinyl compound as a constituent component, or two or more kinds of monofunctional vinyl compounds as constituent components.
Examples of the polymerizable vinyl groups include vinyl group, acryloyloxy group, methacryloyloxy group and allyl group.
Examples of the monofunctional vinyl compounds include (meth) acrylic acid compounds, (meth) acrylamide compounds, styrenes, allyl esters, vinyl ethers, vinyl esters and crotonic acid esters.
Examples of the (meth) acrylic acid compounds include (meth) acrylic acid and (meth) acrylic acid esters.
Examples of the (meth) acrylic acid esters include aliphatic (meth) acrylic acid esters such as methyl (meth) acrylate, ethyl (meth) acrylate, n-propyl (meth) acrylate, isopropyl (meth) acrylate, n-butyl (meth) acrylate, isobutyl (meth) acrylate, t-butyl (meth) acrylate, n-pentyl (meth) acrylate, isopentyl (meth) acrylate, neopentyl (meth) acrylate, hexyl (meth) acrylate, heptyl (meth) acrylate, n-octyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, isooctyl (meth) acrylate, n-nonyl (meth) acrylate, isononyl (meth) acrylate, n-decyl (meth) acrylate, isodecyl (meth) acrylate, undecyl (meth) acrylate, dodecyl (meth) acrylate, tridecyl (meth) acrylate, tetradecyl (meth) acrylate, n-octadecyl (meth) acrylate and isooctadecyl  (meth) acrylate; alicyclic (meth) acrylic acid esters such as cyclohexyl (meth) acrylate, isobornyl (meth) acrylate, dicyclopentanyl (meth) acrylate, dicyclopentenyl (meth) acrylate and dicyclopentenyloxyethyl (meth) acrylate; and aromatic (meth) acrylic acid esters such as benzyl (meth) acrylate, phenoxyethyl (meth) acrylate and phenyl (meth) acrylate.
Examples further include (meth) acrylic acid esters having an amino group, such as dimethylaminoethyl (meth) acrylate, diethylaminoethyl (meth) acrylate, N-tert-butylaminoethyl (meth) acrylate and (meth) acryloxyethyltrimethylammonium chloride.
Examples of the (meth) acrylamide compounds include (meth) acrylamide; (meth) acrylonitrile; N-monosubstituted (meth) acrylamide monomers such as N-methylol (meth) acrylamide, N-methoxymethyl (meth) acrylamide, N-butoxymethyl (meth) acrylamide, N-isopropyl (meth) acrylamide and dimethylaminopropyl (meth) acrylamide; and N, N-disubstituted (meth) acrylamide monomers such as N- (meth) acryloylmorpholine, N- (meth) acryloylpyrrolidone, N- (meth) acryloylpiperidine, N- (meth) acryloylpyrrolidine, N- (meth) acryloyl-4-piperidone, N, N-dimethyl (meth) acrylamide and N, N-diethyl (meth) acrylamide.
Examples of the styrenes include styrene, tert-butoxystyrene, α-methyl-tert-butoxystyrene, 4- (1-methoxyethoxy) styrene, 4- (1-ethoxyethoxy) styrene, tetrahydropyranyloxystyrene, adamantyloxystyrene, 4- (2-methyl-2-adamantyloxy) styrene, 4- (1-methylcyclohexyloxy) styrene, trimethylsilyloxystyrene, dimethyl-tert-butylsilyloxystyrene, tetrahydropyranyloxystyrene, benzylstyrene, trifluoromethylstyrene, acetoxystyrene, chlorostyrene, dichlorostyrene, trichlorostyrene, tetrachlorostyrene, pentachlorostyrene, bromostyrene, dibromostyrene, iodostyrene, fluorostyrene, trifluorostyrene, 2-bromo-4-trifluoromethylstyrene, 4-fluoro-3-trifluoromethylstyrene and vinylnaphthalene.
Examples of the allyl esters include allyl acetate, allyl caproate, allyl caprylate, allyl laurate, allyl palmitate, allyl stearate, allyl benzoate, allyl acetoacetate, allyl lactate and allyloxyethanol.
Examples of the vinyl ethers include hexyl vinyl ether, octyl vinyl ether, decyl vinyl ether, ethylhexyl vinyl ether, methoxyethyl vinyl ether, ethoxyethyl vinyl ether, chloroethyl vinyl ether, 1-methyl-2, 2-dimethylpropyl vinyl ether, 2-ethylbutyl vinyl ether, hydroxyethyl vinyl ether,  diethylene glycol vinyl ether, dimethylaminoethyl vinyl ether, diethylaminoethyl vinyl ether, butylaminoethyl vinyl ether, benzyl vinyl ether, tetrahydrofurfuryl vinyl ether, vinyl phenyl ether, vinyl tolyl ether, vinyl chlorophenyl ether, vinyl-2, 4-dichlorophenyl ether, vinyl naphthyl ether and vinyl anthranyl ether.
Examples of the vinyl esters include vinyl butyrate, vinyl isobutyrate, vinyl trimethylacetate, vinyl diethylacetate, vinyl valerate, vinyl caproate, vinyl chloroacetate, vinyl dichloroacetate, vinyl methoxyacetate, vinyl butoxyacetate, vinyl phenylacetate, vinyl acetoacetate, vinyl lactate, vinyl-β-phenylbutyrate and vinyl cyclohexylcarboxylate.
Examples of the crotonic acid esters include butyl crotonate, hexyl crotonate, glycerol monocrotonate, dimethyl itaconate, diethyl itaconate, dibutyl itaconate, dimethyl maleate, dibutyl fumarate, maleic anhydride, maleimide, acrylonitrile, methacrylonitrile and maleonitrile.
The monofunctional vinyl compounds may have a heteroatom other than oxygen atom or may be free from heteroatoms other than oxygen atoms.
For example, the monofunctional vinyl compounds may  have a nitrogen atom or may be free from nitrogen atoms.
For example, the monofunctional vinyl compounds may have a sulfur atom or may be free from sulfur atoms.
For example, the monofunctional vinyl compounds may have a halogen atom or may be free from halogen atoms.
Among the monofunctional vinyl compounds described above, (meth) acrylic acid compounds are preferable as the monofunctional vinyl compounds used in the first block and the second block because excellent mechanical properties are obtained. (Meth) acrylic acid esters are more preferable, and aliphatic (meth) acrylic acid esters are still more preferable.
More specifically, the monofunctional vinyl compound used in the first block is preferably n-butyl acrylate (hereinafter, sometimes abbreviated as nBA) , and the monofunctional vinyl compound used in the second block is preferably methyl methacrylate (hereinafter, sometimes abbreviated as MMA) , although not particularly limited thereto.
The number average molecular weight (Mn) of the arm portion measured by gel permeation chromatography (GPC (RI) ) is not particularly limited, but is preferably 10,000 or more in order to obtain a coating with higher mechanical  properties, and is more preferably 15,000 or more, still more preferably 20,000 or more, and particularly preferably 25,000 or more.
The upper limit of the number average molecular weight (Mn) is not particularly limited. The number average molecular weight (Mn) may be 100,000 or less, may be 60,000 or less, or may be 50,000 or less.
[GPC (RI) measurement]
The GPC (RI) number average molecular weight (Mn) may be determined by the following GPC (RI) measurement method.
Measurement device: High-performance GPC device ( "HLC-8220GPC" manufactured by Tosoh Corporation)
Columns: Guard column HXL-H manufactured by Tosoh Corporation
+ TSKgel G5000HXL manufactured by Tosoh Corporation
+ TSKgel G4000HXL manufactured by Tosoh Corporation
+ TSKgel G3000HXL manufactured by Tosoh Corporation
+ TSKgel G2000HXL manufactured by Tosoh Corporation
Detector: RI (differential refractometer)
Data processor: SC-8010 manufactured by Tosoh Corporation
Measurement conditions: Column temperature 40℃ Solvent tetrahydrofuran Flow rate 1.0 ml/min
Standard: Polystyrene
Sample: A tetrahydrofuran solution having a resin solid concentration of 0.5 mass%is microfiltered (100 μl) .
It is difficult to measure the molecular weight of the arm portion alone of the star-shaped polymer. Thus, the number average molecular weight of the arm portion may be determined by, for example, synthesizing the arm portion by living radical polymerization and subjecting the arm portion alone to the method described above.
The mass ratio of the core portion to the arm portion (core portion: arm portion) is not particularly limited, but is preferably 1: 99 to 99: 1, more preferably 1: 99 to 50: 50, still more preferably 3: 97 to 40: 60, and particularly preferably 5: 95 to 20: 80.
The number average molecular weight (Mn) of the star-shaped polymer measured by gel permeation chromatography (GPC (RI) ) is not particularly limited, but is preferably 100,000 or more in order to obtain a coating with higher mechanical properties, and is more preferably 200,000 or more, and particularly preferably 300,000 or more.
The upper limit of the number average molecular weight (Mn) is not particularly limited. The number average  molecular weight (Mn) may be 1,000,000 or less, may be 800,000 or less, or may be 700,000 or less.
The weight average molecular weight (Mw) of the star-shaped polymer measured by size-exclusion chromatography (GPC/SEC) is 100,000 or more, and, in order to obtain a coating with higher mechanical properties, is preferably 200,000 or more, more preferably 300,000 or more, and particularly preferably 400,000 or more.
In order to obtain a coating having excellent mechanical properties, the weight average molecular weight (Mw) of the star-shaped polymer is 100,000 or more. If the weight average molecular weight (Mw) of the star-shaped polymer is less than 100,000, a coating having excellent mechanical properties cannot be obtained.
The upper limit of the weight average molecular weight (Mw) is not particularly limited. The weight average molecular weight (Mw) may be 5,000,000 or less, may be 4,500,000 or less, or may be 4,000,000 or less.
The number of arm portions present in the star-shaped polymer corresponds to the number of polymerization initiation groups capable of serving as initiation points in the CD skeleton-containing compound. For example, the number of arm portions is up to 21 in the case of the CD  skeleton-containing compound of the formula (1) described hereinabove.
The number of arm portions in the star-shaped polymer is not particularly limited, but is preferably 4 or more for the reason that excellent mechanical strength is obtained, and is more preferably 7 or more, still more preferably 10 or more, and particularly preferably 15 or more. On the other hand, the number of arm portions in the star-shaped polymer is preferably 24 or less in order to prevent gelation.
For example, the star-shaped polymer according to the present invention is obtained by a production method described later.
The star-shaped polymer according to the present invention is preferably produced by controlled radical (living radical) polymerization. In particular, the star-shaped polymer according to the present invention is preferably produced by ATRP (atom transfer radical polymerization) or RAFT polymerization (reversible addition/fragmentation chain transfer polymerization) . The controlled radical (living radical) polymerization such as ATRP or RAFT polymerization proceeds linearly while preventing the recombination of growing radicals or disproportionation, and can precisely synthesize a polymer  having a narrow molecular weight distribution.
For example, the tip of the arm portion of the star-shaped polymer has a polymerization initiation terminal formed by living radical polymerization.
When, for example, the star-shaped polymer is produced by ATRP, the tip of the arm portion has a residue after radical cleavage of an organic halogen compound.
When, for example, the star-shaped polymer is produced by RAFT polymerization, the tip of the arm portion has a residue after thermal cleavage of a radical polymerization initiator, or a residue after cleavage of a chain transfer agent. The "polymerization initiation terminal formed by living radical polymerization" may be an initiation terminal of a polymer chain resulting from a growth reaction that is triggered by a radical generated by thermal cleavage of a radical polymerization initiator, or may be an initiation terminal of a polymer chain resulting from a growth reaction that is triggered by a radical generated by cleavage of a chain transfer agent.
(Method for producing star-shaped polymer)
A production method according to the present invention will be described hereinafter. However, the scope of the present invention is not limited to the embodiment described  below.
The method for producing a star-shaped polymer according to the present invention is characterized in that a star-shaped polymer is obtained by performing living radical polymerization while using a CD skeleton-containing compound as an initiator in such a manner that a monofunctional vinyl compound as a first block constituent component is polymerized beforehand to form an intermediate polymer as a macroinitiator, and further a monofunctional vinyl compound as a second block constituent component is polymerized to form a second block.
As compared to one-pot synthesis, the production method according to the present invention allows for easy controlling of the monomer conversion ratios of the monofunctional vinyl compounds that form the respective blocks, and can prevent the occurrence of gelation by coupling of the star-shaped polymer molecules. The production method will be described in detail below focusing on the case where the living radical polymerization is ATRP.
The method for producing a star-shaped polymer according to the present invention includes a step 1 of obtaining a core portion by synthesizing a CD skeleton-containing compound, a step 2 of obtaining an intermediate  polymer as a macroinitiator including the core portion and a first block, and a step 3 of obtaining a star-shaped polymer including the core portion, the first block and a second block, and may further include additional steps as required.
These steps will be described below.
<Step 1>
In the step 1, a cyclodextrin, a compound containing a polymerization initiation group, and a solvent are added and mixed with one another to prepare a CD skeleton-containing compound. The step 1 may be performed using a conventionally known process.
The CD skeleton-containing compound corresponds to the core portion of the star-shaped polymer according to the present invention.
The CD skeleton-containing compound may be a commercial product. When the CD skeleton-containing compound is a commercial product, the step 1 may be omitted.
The cyclodextrin that is used may be one described in the section of the core portion of the star-shaped polymer. For example, the cyclodextrin may be β-cyclodextrin.
The cyclodextrins may be used singly, or two or more may be used in combination.
In the compound containing a polymerization initiation group, the polymerization initiation group may be one described in the section of the core portion of the star-shaped polymer. For example, the polymerization initiation group may be a 2-bromoisobutyryl group. For example, the compound containing a polymerization initiation group may be 2-bromoisobutyryl bromide.
The compounds containing a polymerization initiation group may be used singly, or two or more may be used in combination.
In the CD skeleton-containing compound obtained in the step 1, the number of polymerization initiation groups corresponds to the number of arms in the star-shaped polymer that will be produced. Thus, the number of polymerization initiation groups is preferably determined in accordance with the number of arms in the star-shaped polymer that is to be produced. When, for example, a star-shaped polymer having 4 arms is to be produced, the number of polymerization initiation groups serving as polymerization initiation points is 4. When a star-shaped polymer having 21 arms is to be produced, the number of polymerization initiation groups is 21. The number of polymerization initiation groups may be controlled by controlling the blending ratio of the compound containing a polymerization  initiation group to the cyclodextrin.
As described above, the molar ratio of the amount added of the compound containing a polymerization initiation group to the amount added of the cyclodextrin may be controlled appropriately in accordance with the desired number of arms in the target star-shaped polymer.
When, for example, the desired number of arms in the star-shaped polymer is 4, the compound containing a polymerization initiation group is preferably used in a molar amount four to five times the moles of the cyclodextrin.
When, for example, the desired number of arms in the star-shaped polymer is 7, the compound containing a polymerization initiation group is preferably used in a molar amount seven to nine times the moles of the cyclodextrin.
When, for example, the desired number of arms in the star-shaped polymer is 14, the compound containing a polymerization initiation group is preferably used in a molar amount fourteen to twenty-three times the moles of the cyclodextrin.
When, for example, the desired number of arms in the star-shaped polymer is 21, the compound containing a polymerization initiation group is preferably used in a  molar amount twenty-one to forty-two times the moles of the cyclodextrin.
The solvent is not particularly limited. Examples of the solvents include hydrocarbon solvents such as hexane, octane, decane, isodecane, cyclohexane, methylcyclohexane, toluene, xylene and ethylbenzene; alcohol solvents such as methanol, ethanol, propanol, isopropanol (2-propanol) , butanol, isobutanol, hexanol, benzyl alcohol and cyclohexanol; glycol solvents such as ethylene glycol, diethylene glycol, propylene glycol, dipropylene glycol, methylcellosolve, ethylcellosolve, butylcellosolve, propylene glycol monomethyl ether, propylene glycol monoethyl ether, propylene glycol propyl ether, diglyme, triglyme, tetraglyme, dipropylene glycol dimethyl ether, butylcarbitol, butyl triethylene glycol, methyl dipropylene glycol, methylcellosolve acetate, propylene glycol monomethyl ether acetate, dipropylene glycol butyl ether acetate and diethylene glycol monobutyl ether acetate; ether solvents such as diethyl ether, dipropyl ether, methyl cyclopropyl ether, tetrahydrofuran, dioxane and anisole; ketone solvents such as methyl ethyl ketone, diethyl ketone, methyl isobutyl ketone, cyclohexanone, isophorone and acetophenone; ester solvents such as methyl acetate, ethyl acetate, butyl acetate, propyl acetate, methyl butyrate,  ethyl butyrate, caprolactone, methyl lactate, ethyl lactate, dimethyl succinate, dimethyl adipate and dimethyl glutarate; halogenated solvents such as chloroform and dichloroethane; amide solvents such as dimethylformamide, dimethylacetamide, pyrrolidone, N-methylpyrrolidone and caprolactam; and other solvents such as dimethyl sulfoxide, sulfolane, tetramethylurea, dimethylimidazolidinone, ethylene carbonate, propylene carbonate and dimethyl carbonate. The solvents may be used singly, or two or more may be used in combination.
In the step 1, a catalyst may be further mixed in order to enhance the reaction rate and the reaction yield. The catalyst is preferably an organic amine. Examples of the organic amines include trimethylamine, triethylamine, dimethylbutylamine, tributylamine, trioctylamine, dodecyldimethylamine, dimethylaminoethanol, triethanolamine, tripropanolamine, diazabicycloundecene, diazabicyclooctane, N-methylmorpholine, pyridine and 4-dimethylaminopyridine.
For example, the catalyst is added in an amount of about 0.001 to 2 mass%relative to the mass of the monofunctional vinyl compound.
The reaction temperature is not particularly limited but is usually room temperature. The amount of reaction  time is not particularly limited but is usually 1 to 48 hours. The reaction atmosphere may be air or an atmosphere of an inert gas such as nitrogen gas or argon gas.
When the step 1 involves β-cyclodextrin as the cyclodextrin and 2-bromoisobutyryl bromide as the compound containing a polymerization initiation group, the CD skeleton-containing compound that is obtained is represented by the following general formula (1) :
[Chem. 2]
Figure PCTCN2022107909-appb-000003
where R 1 independently denotes a hydrogen atom or a 2-bromoisobutyryl group, and *denotes a bond.
The completion of the reaction may be easily confirmed by measurement such as thin-layer chromatography, liquid chromatography, gas chromatography or  1H-NMR. After the completion of the reaction, the product obtained may be  isolated by a known operation such as filtration, concentration, extraction or purification.
<Step 2>
In the step 2, a monofunctional vinyl compound as a first block constituent component is polymerized by living radical polymerization in the presence of a catalyst while using the CD skeleton-containing compound obtained in the step 1 as an initiator, and thereby an intermediate polymer is prepared that includes a core portion and a plurality of first blocks each including a structural unit derived from the monofunctional vinyl compound and bonded to the initiation point of the core portion.
The intermediate polymer corresponds to the core portion and the first blocks in the star-shaped polymer according to the present invention.
The intermediate polymer is a macroinitiator and is used in a step 3 described later.
In the step 2, for example, the CD skeleton-containing compound, a catalyst, a ligand, a monofunctional vinyl compound and a solvent are added and mixed with one another. Subsequently, the dissolved oxygen in the system is removed by blowing nitrogen into the system, and the system is then heated to perform living radical polymerization of the  monofunctional vinyl compound.
A single kind, or two or more kinds of monofunctional vinyl compounds may be used to form the first blocks.
Examples of the monofunctional vinyl compounds include the monofunctional vinyl compounds illustrated in the description of the star-shaped polymer according to the present invention. For example, the monofunctional vinyl compound may be n-butyl acrylate.
The solvent is not particularly limited. Examples of the solvents include the solvents illustrated in the description of the step 1.
The solid concentration of the monofunctional vinyl compound in the solvent is preferably 1 mass%or more, more preferably 3 mass%or more, and still more preferably 5 mass%or more. On the other hand, the solid concentration of the monofunctional vinyl compound in the solvent is preferably 40 mass%or less, more preferably 35 mass%or less, and still more preferably 30 mass%or less.
The blending ratio of the CD skeleton-containing compound to the monofunctional vinyl compound is not particularly limited and is variable depending on the number of polymerization initiation groups in the CD skeleton- containing compound that is used. To prevent gelation, the molar ratio (CD skeleton-containing compound: monofunctional vinyl compound) is preferably 1: 2 to 1: 7.5, and more preferably 1: 3 to 1: 7.
A transition metal complex may be suitably used as the catalyst. Examples of such catalysts include complexes of transition metals of Group 3 to Group 10, in particular, Group 8 to Group 10 in the periodic table (the long form of periodic table of 18 Groups) . Specific examples of the catalysts include copper (I) chloride, copper (II) chloride, copper (I) bromide, copper (II) bromide, chloro (indenyl) bis (triphenylphosphine) ruthenium (II) (dichloromethane adduct) and chloro (indenyl) bis (η5-pentamethylcyclopentadiene) [bis (triphenylphosphine) ] ruthenium (II) . Among these, copper (II) chloride is preferable because of excellent reactivity.
For example, the ligand is used to increase the catalytic activity of the copper compound. Examples of the ligands include 2, 2'-bipyridyl and derivatives thereof; 1, 10-phenanthroline and derivatives thereof; and polyamines such as tetramethylethylenediamine, pentamethyldiethylenetriamine and tris [2- (dimethylamino) ethyl] amine. Among these ligands, tris [2-  (dimethylamino) ethyl] amine is preferable.
In the living radical polymerization, the blending amounts are usually designed in molar ratio. The blending ratio of the CD skeleton-containing compound to the monofunctional vinyl compound is determined based on the number of polymerization initiation groups in the CD skeleton-containing compound that is used, the design of arm length and the design of arm composition (the proportion in the arms) , and next the amount of the catalyst is determined in the catalyst/CD skeleton-containing compound molar ratio. The molar ratio (catalyst/CD skeleton-containing compound) of the catalyst to the CD skeleton-containing compound is usually 0.01 to 1 mol, and good reactivity is advantageously obtained. After the amount of the catalyst is determined, the amount of the ligand is determined based on the ligand/catalyst ratio (by mol) . The molar ratio (ligand/catalyst) of the ligand to the catalyst is usually 0.5 to 10 mol, and good reactivity is advantageously obtained.
In the step 2, additives may be mixed as required in order to increase the catalytic activity. Examples of the additives include Lewis acids (such as, for example, aluminum alkoxides) , inorganic salts (such as, for example,  sodium carbonate and sodium benzoate) and reductants (such as, for example, tin 2-ethylhexanoate) . These additives are added in an amount of, for example, about 0.001 to 2 mass%relative to the mass of the functional compound.
The reaction temperature is variable depending on factors such as the composition of the arm portion, and the number of arms, but is usually -50℃ to 400℃, preferably 0℃ to 300℃, and more preferably 40 to 250℃. The amount of reaction time is usually 1 to 48 hours. The reaction atmosphere may be air or an atmosphere of an inert gas such as nitrogen gas or argon gas.
The living radical polymerization in the step 2 is preferably carried out until the monomer conversion ratio of the monofunctional vinyl compound reaches 10%or more, more preferably 13%or more, and still more preferably 15%or more. On the other hand, the living radical polymerization is preferably performed until the monomer conversion ratio of the monofunctional vinyl compound reaches 60%or less, more preferably 50%or less, and still more preferably 40%or less.
When the monomer conversion ratio of the monofunctional vinyl compound is in the above range, the star-shaped polymer that is obtained tends to be free from gelation.
The monomer conversion ratio may be calculated using gas chromatography measurement. The peak area of the monomer before the start of polymerization (the initial monomer peak area) is measured using tridecane as an internal standard. After the start of polymerization, the peak area decreases with lowering of the monomer concentration. Similarly to before the start of polymerization, the peak area of the monomer during the polymerization reaction (the monomer peak area during reaction) is measured using tridecane as an internal standard. In this manner, the monomer conversion ratio of the monofunctional vinyl compound may be calculated. Specifically, the monomer conversion ratio may be determined from the following equation.
[Math. 1]
Figure PCTCN2022107909-appb-000004
The completion of the reaction may be easily confirmed by measurement such as thin-layer chromatography, liquid chromatography, gas chromatography or  1H-NMR. After the completion of the reaction, the product obtained may be isolated by a known operation such as filtration, concentration, extraction or purification. In the step 2,  the intermediate polymer that is produced is preferably purified after the completion of the reaction. By performing purification to remove the unreacted monofunctional vinyl compound used to form the first blocks, the living radical polymerization reaction in the step 3 described below is allowed to proceed easily.
<Step 3>
In the step 3, a monofunctional vinyl compound as a second block constituent component is polymerized by living radical polymerization in the presence of a catalyst while using the intermediate polymer from the step 2 as a macroinitiator, and thereby a star-shaped polymer is prepared that includes a plurality of second blocks each including a structural unit derived from the monofunctional vinyl compound and bonded to the first block.
In the step 3, for example, the intermediate polymer, a catalyst, a ligand, a monofunctional vinyl compound and a solvent are added and mixed with one another. Subsequently, the dissolved oxygen in the system is removed by blowing nitrogen into the system, and the system is then heated to perform living radical polymerization of the monofunctional vinyl compound.
A single kind, or two or more kinds of monofunctional vinyl compounds may be used to form the second blocks.
Examples of the monofunctional vinyl compounds include the monofunctional vinyl compounds illustrated in the description of the star-shaped polymer according to the present invention. For example, the monofunctional vinyl compound may be methyl methacrylate.
The solvent is not particularly limited. Examples of the solvents include the solvents illustrated in the description of the step 1.
The solid concentration of the monofunctional vinyl compound in the solvent is preferably 1 mass%or more, more preferably 3 mass%or more, and still more preferably 5 mass%or more. On the other hand, the solid concentration of the monofunctional vinyl compound in the solvent is preferably 40 mass%or less, more preferably 35 mass%or less, and still more preferably 30 mass%or less.
The blending ratio of the intermediate polymer to the monofunctional vinyl compound is not particularly limited and is variable depending on the number of arms that is designed. To prevent gelation, the molar ratio (intermediate polymer: monofunctional vinyl compound) is preferably 1: 3 to 1: 8, and more preferably 1: 4 to 1: 7.
Examples of the catalysts and of the ligands include the catalysts and the ligands illustrated in the description of the step 2.
The amount added of the catalyst is usually 0.01 to 1 mol per mol of the monofunctional vinyl compound, and good reactivity is advantageously obtained. After the amount of the catalyst is determined, the amount of the ligand is determined based on the ligand/catalyst ratio (by mol) . The molar ratio (ligand/catalyst) of the ligand to the catalyst is usually 0.5 to 10 mol, and good reactivity is advantageously obtained.
In the step 3, the additives illustrated in the description of the step 2 may be used as required. The additives are added in an amount of, for example, about 0.001 to 2 mass%relative to the mass of the functional compound.
The reaction temperature is variable depending on factors such as the composition of the arm portion, and the number of arms, but is usually -50℃ to 400℃, preferably 0℃ to 300℃, and more preferably 40 to 250℃. The amount of reaction time is usually 1 to 48 hours. The reaction atmosphere may be air or an atmosphere of an inert gas such  as nitrogen gas or argon gas.
The living radical polymerization in the step 3 is preferably carried out until the monomer conversion ratio of the monofunctional vinyl compound reaches 10%or more. On the other hand, the living radical polymerization is preferably performed until the monomer conversion ratio of the monofunctional vinyl compound reaches 40%or less, more preferably 33%or less, and still more preferably 30%or less.
When the monomer conversion ratio of the monofunctional vinyl compound is in the above range, the star-shaped polymer that is obtained tends to be free from gelation.
The completion of the reaction may be easily confirmed by measurement such as thin-layer chromatography, liquid chromatography, gas chromatography or  1H-NMR. After the completion of the reaction, the star-shaped polymer according to the present invention may be isolated by a known operation such as filtration, concentration, extraction or purification.
(Paint)
A paint according to the present invention includes the star-shaped polymer according to the present invention, and  further includes additional components such as an organic solvent as required.
The content of the star-shaped polymer in the paint is not particularly limited.
The organic solvent is not particularly limited. Examples thereof include ketone solvents, cyclic ether solvents, ester solvents, aromatic solvents, alcohol solvents and glycol ether solvents.
Examples of the ketone solvents include acetone, methyl ethyl ketone and methyl isobutyl ketone.
Examples of the cyclic ether solvents include tetrahydrofuran and dioxolane.
Examples of the ester solvents include methyl acetate, ethyl acetate and butyl acetate.
Examples of the aromatic solvents include toluene and xylene.
Examples of the alcohol solvents include methanol, isopropanol (2-propanol) and butanol.
Examples of the glycol ether solvents include ethylene glycol monoethyl ether, ethylene glycol monobutyl ether, propylene glycol monomethyl ether, propylene glycol monopropyl ether and diethylene glycol monoethyl ether.
The organic solvents may be used singly, or two or more may be used in combination.
The organic solvent is used mainly to dissolve the star-shaped polymer and to control the viscosity of the paint. It is usually preferable to control the nonvolatile content to the range of 30 to 90 mass%. The paint according to the present invention has a relatively low viscosity and thus the amount of the organic solvent used may be small as compared to, for example, a usual acrylic acrylate monomer having a high molecular weight.
The paint may contain additional components, for example, additives generally used in paints such as UV absorbers, antioxidants, silicone additives, fluorine additives, organic beads, antistatic agents, silane-coupling agents, inorganic microparticles, inorganic fillers, rheology control agents, defoaming agents, antifogging agents and colorants.
Examples of the UV absorbers include triazine derivatives, 2- (2'-xanthenecarboxy-5'-methylphenyl) benzotriazole, 2- (2'-o-nitrobenzyloxy-5'-methylphenyl) benzotriazole, 2-xanthenecarboxy-4-dodecyloxybenzophenone and 2-o-nitrobenzyloxy-4-dodecyloxybenzophenone.
Examples of the triazine derivatives include 2- [4- { (2- hydroxy-3-dodecyloxypropyl) oxy} -2-hydroxyphenyl] -4, 6-bis (2, 4-dimethylphenyl) -1, 3, 5-triazine and 2- [4- { (2-hydroxy-3-tridecyloxypropyl) oxy} -2-hydroxyphenyl] -4, 6-bis (2, 4-dimethylphenyl) -1, 3, 5-triazine.
Examples of the antioxidants include hindered phenol antioxidants, hindered amine antioxidants, organic sulfur antioxidants and phosphoric acid ester antioxidants.
Examples of the silicone additives include polyorganosiloxanes having an alkyl group and/or a phenyl group, polydimethylsiloxanes having a polyether-modified acrylic group, and polydimethylsiloxanes having a polyester-modified acrylic group.
Examples of the polyorganosiloxanes having an alkyl group and/or a phenyl group include dimethylpolysiloxane, methylphenylpolysiloxane, cyclic dimethylpolysiloxane, methylhydrogenpolysiloxane, polyether-modified dimethylpolysiloxane copolymer, polyester-modified dimethylpolysiloxane copolymer, fluorine-modified dimethylpolysiloxane copolymer and amino-modified dimethylpolysiloxane copolymer.
Examples of the fluorine additives include "MEGAFACE" series manufactured by DIC Corporation.
Examples of the organic beads include polymethyl methacrylate beads, polycarbonate beads, polystyrene beads, polyacrylic styrene beads, silicone beads, glass beads, acrylic beads, benzoguanamine resin beads, melamine resin beads, polyolefin resin beads, polyester resin beads, polyamide resin beads, polyimide resin beads, polyfluoroethylene resin beads and polyethylene resin beads.
The average particle diameter of these organic beads is preferably in the range of 1 to 10 μm.
Examples of the antistatic agents include pyridinium, imidazolium, phosphonium, ammonium or lithium salts of bis (trifluoromethanesulfonyl) imide or bis (fluorosulfonyl) imide.
The paint according to the present invention may further include additional components such as resins, and organic or inorganic particles in order to control the viscosity or the refractive index, to control the tone of a coating, and to control other paint properties and coating properties.
Examples of the resins include acrylic resins, phenolic resins, polyester resins, polystyrene resins, urethane resins, urea resins, melamine resins, alkyd resins, epoxy  resins, polyamide resins, polycarbonate resins, petroleum resins and fluororesins.
Examples of the organic or inorganic particles include polytetrafluoroethylene (PTFE) , polyethylene, polypropylene, carbon, titanium oxide, alumina, copper and silica microparticles.
The paint according to the present invention may be produced by any method without limitation. For example, the paint may be obtained by mixing the star-shaped polymer, the organic solvent, and optionally other components such as additives and resins.
(Coating)
A coating according to the present invention is formed from the paint according to the present invention.
For example, the coating is obtained in such a manner that after stirring of the paint containing components such as the star-shaped polymer and the organic solvent, the paint is applied onto a substrate such as a PET film, and the wet film is dried by heating.
The coating according to the present invention may be used in any applications without limitation, but is useful as a coating in a hard coat film. Furthermore, the coating  according to the present invention is expected to be applied to soft electronics materials (such as organic thin-film solar cells, wearables and battery electrolytes) , self-repairing materials, surface modifiers, and improvements in functionality of existing polymer products (such as coating UV resins, IJ printer ink binder resins and optical resins) .
[Examples]
The present invention will be described in greater detail hereinbelow based on Examples. However, the scope of the present invention is not limited to such Examples.
[GPC (RI) measurement]
The GPC (RI) number average molecular weight (Mn) may be determined by the following GPC (RI) measurement method.
Measurement device: High-performance GPC device ( "HLC-8220GPC" manufactured by Tosoh Corporation)
Columns: Guard column HXL-H manufactured by Tosoh Corporation
+ TSKgel G5000HXL manufactured by Tosoh Corporation
+ TSKgel G4000HXL manufactured by Tosoh Corporation
+ TSKgel G3000HXL manufactured by Tosoh Corporation
+ TSKgel G2000HXL manufactured by Tosoh Corporation
Detector: RI (differential refractometer)
Data processor: SC-8010 manufactured by Tosoh  Corporation
Measurement conditions: Column temperature 40℃ Solvent tetrahydrofuran Flow rate 1.0 ml/min
Standard: Polystyrene
Sample: A tetrahydrofuran solution having a resin solid concentration of 0.5 mass%was microfiltered (100 μl) .
[Arm length]
The arm length of a star-shaped polymer was calculated from the following equation.
[Math. 2]
Figure PCTCN2022107909-appb-000005
[Monomer conversion ratio]
A sample weighing 0.1 g was sampled from the polymerization liquid with a syringe before the start of polymerization, was diluted with 2 g of tetrahydrofuran containing 2,000 ppm of tridecane as an internal standard, and was analyzed by gas chromatography. Next, a sample weighing 0.1 g was sampled during the polymerization reaction, was similarly diluted with 2 g of tetrahydrofuran containing tridecane, and was analyzed by gas chromatography.  Based on the measured values, the monomer conversion ratio was calculated from the following equation.
[Math. 3]
Figure PCTCN2022107909-appb-000006
[Preparation of initiators]
(Initiator Preparation Example 1)
<Preparation of cyclodextrin skeleton-containing compound having 21 initiation points>
β-Cyclodextrin (hereinafter, abbreviated as β-CD) (3.41 g, 3 mmol, used after vacuum dried at 80℃ for 1 hour) was dissolved into 30 ml of anhydrous 1-methyl-2-pyrrolidione (hereinafter, abbreviated as NMP) . A small amount of 4- (N, N-dimethylamino) pyridine (hereinafter, abbreviated as DMAP) as a catalyst was added, and the mixture was cooled to 0℃. Next, 2-bromoisobutyryl bromide (29.0 ml, 126 mmol) was dissolved into anhydrous NMP (15 ml) , and the resultant solution was added dropwise to the β-CD solution held at 0℃ while performing stirring with a magnetic stirrer. The reaction temperature was maintained at 0℃ for 2 hours, and was subsequently increased gradually to ambient. Thereafter, the reaction was continued for 1 day. Here, the amount added of 2-bromoisobutyryl bromide was twice the amount  required.
The reaction liquid was diluted with 50 ml of dichloromethane, and was sequentially washed with a saturated aqueous NaHCO 3 solution (100 ml, twice) , an aqueous NaCl solution (100 ml, twice) and water (100 ml, twice) . The resultant solution was dropped to n-hexane to form a brown deposit. The deposit was filtered, washed with hexane twice, and vacuum dried at 40℃ to give a CD skeleton-containing compound 21Br-β-CD having 21 bromo groups as initiation points.
The introduction of bromo groups was confirmed by  1H-NMR, specifically, by comparing the integrals of signals assigned to methyl protons (about 1.88 ppm) in the initiation groups -OCO-C (CH 3) . Furthermore, the introduction was also confirmed based on the attenuation of the signal assigned to the 1-position protons in β-CD observed at 4.80-5.50 ppm.
(Initiator Preparation Examples 2 to 4)
<Preparation of cyclodextrin skeleton-containing compounds having 4, 7 or 14 initiation points>
The procedure in Initiator Synthesis Example 1 was repeated, except that the reaction involved 2-bromoisobutyryl bromide (8.29 ml, 12 mmol, 1.0 time the amount required) to prepare a CD skeleton-containing compound 4Br-β-CD having 4 bromo groups as initiation points,  except that the reaction involved 2-bromoisobutyryl bromide (17.4 ml, 25.2 mmol, 1.2 times the amount required) to prepare a CD skeleton-containing compound 7Br-β-CD having 7 bromo groups as initiation points, or except that the reaction involved 2-bromoisobutyryl bromide (46.4 ml, 67.2 mmol, 1.6 times the amount required) to prepare a CD skeleton-containing initiator 14Br-β-CD having 14 bromo groups as initiation points. 4Br-β-CD represents Initiator Preparation Example 2, 7Br-β-CD Initiator Preparation Example 3, and 14Br-β-CD Initiator Preparation Example 4.
[Preparation of intermediate polymers as macroinitiators]
(Intermediate Polymer Preparation Example 1)
<Preparation of intermediate polymer having the number of arms of 21, an arm length of about 5,000 and an arm composition of BA>
CuCl 2·2H 2O catalyst (5.4 mg, 0.032 mmol) and tris (dimethylaminoethyl) amine ligand (hereinafter, sometimes abbreviated as Me6TREN) (29.0 mg, 0.126 mmol) were dissolved into 0.5 g of N, N-dimethylformamide (hereinafter, abbreviated as DMF) , and the solution was fed to a 100-ml four-necked flask. Next, 21Br-β-CD (213.2 mg, 0.050 mmol) obtained in Initiator Preparation Example 1 was fed. As a monomer, n-butyl acrylate (hereinafter, abbreviated as BA) was added in an amount (26.24 g, 0.205 mol) 5 times greater  than the required amount in order to prevent star coupling, and anisole solvent (50 g) was subsequently added. The mixture was bubbled with N 2 at 100 mL/min for 1 hour to remove oxygen in the system. Next, tin 2-ethylhexanoate Sn (EH)  2 reductant (0.1404 g, 0.347 mmol) was added with a syringe to the flask in a nitrogen gas atmosphere to reduce the Cu catalyst complex, thereby initiating polymerization. Initiator/CuCl 2/Me6TREN/Sn (EH)  2 = 1/0.63/2.52/6.93 (by mol) . Here, the amount of BA, increased by 5 times, may be counted as an amount of solvent, and thus the solid concentration in the reaction liquid is calculated to be about 7%.
Next, the flask was tightly closed with a glass stopper and was soaked in an oil bath that had been set at 60℃, and the polymerization continued. The monomer conversion ratio and the molecular weight of the polymer were measured by GC measurement and GPC measurement, respectively. When the BA conversion ratio approached 20%, the temperature was lowered and air was injected into the system to terminate the polymerization.
The polymer solution was transferred to a beaker soaked in an ice bath. Next, methanol was continuously dropped to the beaker while performing stirring until the solution became clouded, and a deposit was obtained. The dropping was stopped, and the solution was allowed to stand for a predetermined amount of time and was filtered to remove the  liquid. Thus, an intermediate polymer 21Star-PBA was obtained that had an arm length of about 5,000 and an arm composition of BA.
(Intermediate Polymer Preparation Example 2)
<Preparation of intermediate polymer having the number of arms of 21, an arm length of about 6,000 and an arm composition of BA>
An intermediate polymer 21Star-PBA having an arm length of about 6,000 and an arm composition of BA was prepared by the same method as Intermediate Polymer Synthesis Example 1, except that the BA monomer was added in an amount (31.50 g, 0.246 mol) 5 times greater than the required amount in order to prevent star coupling. The amount of BA, increased by 5 times, may be counted as an amount of solvent, and thus the solid concentration in the reaction liquid is calculated to be about 8%. After the BA conversion ratio was confirmed to have reached 20%, the temperature was lowered and air was injected into the system to terminate the polymerization. The polymer solution was transferred to a beaker soaked in an ice bath. Next, methanol was continuously dropped to the beaker while performing stirring until the solution became clouded, and a deposit was obtained. The dropping was stopped, and the solution was allowed to stand for a predetermined amount of time and was filtered to remove the  liquid. Thus, an intermediate polymer 21Star-PBA was obtained that had an arm length of about 6,000 and an arm composition of BA.
(Intermediate Polymer Preparation Example 3)
<Preparation of intermediate polymer having the number of arms of 4, an arm length of about 6,000 and an arm composition of BA>
CuCl 2·2H 2O catalyst (5.7 mg, 0.034 mmol) and Me6TREN (23.2 mg, 0.101 mmol) were dissolved into 1.0 g of DMF, and the solution was fed to a 100-ml four-necked flask. Next, 4Br-β-CD (484.7 mg, 0.28 mmol) obtained in Initiator Preparation Example 2 was fed. As a monomer, n-butyl acrylate (hereinafter, abbreviated as BA) was added in an amount (13.49 g, 0.105 mol) 2 times greater than the required amount in order to prevent star coupling, and anisole solvent (40 g) was subsequently added. The mixture was bubbled with N 2 at 100 mL/min for 1 hour to remove oxygen in the system. Next, tin 2-ethylhexanoate Sn (EH)  2 reductant (0.1361 g, 0.336 mmol) was added with a syringe to the flask in a nitrogen gas atmosphere to reduce the Cu catalyst complex, thereby initiating polymerization. Initiator/CuCl 2/Me6TREN/Sn (EH)  2 = 1/0.12/0.36/1.2 (by mol) . Here, the amount of BA, increased by 2 times, may be counted as an amount of solvent, and thus the solid concentration in  the reaction liquid is calculated to be about 13%.
Next, the flask was tightly closed with a glass stopper and was soaked in an oil bath that had been set at 60℃, and the polymerization continued. The monomer conversion ratio and the molecular weight of the polymer were measured by GC measurement and GPC measurement, respectively. When the BA conversion ratio approached 50%, the temperature was lowered and air was injected into the system to terminate the polymerization.
The polymer solution was transferred to a beaker soaked in an ice bath. Next, methanol was continuously dropped to the beaker while performing stirring until the solution became clouded, and a deposit was obtained. The dropping was stopped, and the solution was allowed to stand for a predetermined amount of time and was filtered to remove the liquid. Thus, an intermediate polymer 4 Star-PBA was obtained that had the number of arms of 4, an arm length of about 6,000 and an arm composition of BA.
(Intermediate Polymer Preparation Example 4)
<Preparation of intermediate polymer having the number of arms of 7, an arm length of about 6,000 and an arm composition of BA>
CuCl 2·2H 2O catalyst (5.4 mg, 0.032 mmol) and Me6TREN (21.8 mg, 0.095 mmol) were dissolved into 0.5 g of DMF, and  the solution was fed to a 100-ml four-necked flask. Next, 7Br-β-CD (326.7 mg, 0.15 mmol) obtained in Initiator Preparation Example 3 was fed. As a monomer, n-butyl acrylate (hereinafter, abbreviated as BA) was added in an amount (18.49 g, 0.147 mol) 3 times greater than the required amount in order to prevent star coupling, and anisole solvent (45 g) was subsequently added. The mixture was bubbled with N 2 at 100 mL/min for 1 hour to remove oxygen in the system. Next, tin 2-ethylhexanoate Sn (EH)  2 reductant (0.140 g, 0.347 mmol) was added with a syringe to the flask in a nitrogen gas atmosphere to reduce the Cu catalyst complex, thereby initiating polymerization. Initiator/CuCl 2/Me6TREN/Sn (EH)  2 = 1/0.21/0.63/2.31 (by mol) . Here, the amount of BA, increased by 3 times, may be counted as an amount of solvent, and thus the solid concentration in the reaction liquid is calculated to be about 10%.
Next, the flask was tightly closed with a glass stopper and was soaked in an oil bath that had been set at 60℃, and the polymerization continued. The monomer conversion ratio and the molecular weight of the polymer were measured by GC measurement and GPC measurement, respectively. When the BA conversion ratio approached 33%, the temperature was lowered and air was injected into the system to terminate the polymerization.
The polymer solution was transferred to a beaker soaked  in an ice bath. Next, methanol was continuously dropped to the beaker while performing stirring until the solution became clouded, and a deposit was obtained. The dropping was stopped, and the solution was allowed to stand for a predetermined amount of time and was filtered to remove the liquid. Thus, an intermediate polymer 7Star-PBA was obtained that had the number of arms of 7, an arm length of about 6,000 and an arm composition of BA.
(Intermediate Polymer Preparation Example 5)
<Preparation of intermediate polymer having the number of arms of 14, an arm length of about 6,000 and an arm composition of BA>
CuCl 2·2H 2O catalyst (6.3 mg, 0.037 mmol) and Me6TREN (25.8 mg, 0.112 mmol) were dissolved into 1.0 g of DMF, and the solution was fed to a 100-ml four-necked flask. Next, 14Br-β-CD (285.2 mg, 0.089 mmol) obtained in Initiator Preparation Example 4 was fed. As a monomer, n-butyl acrylate (hereinafter, abbreviated as BA) was added in an amount (29.90 g, 0.233 mol) 4 times greater than the required amount in order to prevent star coupling, and anisole solvent (53 g) was subsequently added. The mixture was bubbled with N 2 at 100 mL/min for 1 hour to remove oxygen in the system. Next, tin 2-ethylhexanoate Sn (EH)  2 reductant (0.166 g, 0.411 mmol) was added with a syringe to  the flask in a nitrogen gas atmosphere to reduce the Cu catalyst complex, thereby initiating polymerization. Initiator/CuCl 2/Me6TREN/Sn (EH)  2 = 1/0.42/1.26/4.62 (by mol) . Here, the amount of BA, increased by 4 times, may be counted as an amount of solvent, and thus the solid concentration in the reaction liquid is calculated to be about 9%.
Next, the flask was tightly closed with a glass stopper and was soaked in an oil bath that had been set at 60℃, and the polymerization continued. The monomer conversion ratio and the molecular weight of the polymer were measured by GC measurement and GPC measurement, respectively. When the BA conversion ratio approached 25%, the temperature was lowered and air was injected into the system to terminate the polymerization.
The polymer solution was transferred to a beaker soaked in an ice bath. Next, methanol was continuously dropped to the beaker while performing stirring until the solution became clouded, and a deposit was obtained. The dropping was stopped, and the solution was allowed to stand for a predetermined amount of time and was filtered to remove the liquid. Thus, an intermediate polymer 14Star-PBA was obtained that had the number of arms of 14, an arm length of about 6,000 and an arm composition of BA.
(Intermediate Polymer Preparation Example 6)
<Preparation of intermediate polymer having the number of arms of 14, an arm length of about 5,000 and an arm composition of BA>
CuCl 2·2H 2O catalyst (4.8 mg, 0.028 mmol) and Me6TREN (25.8 mg, 0.112 mmol) were dissolved into 1.0 g of DMF, and the solution was fed to a 100-ml four-necked flask. Next, 14Br-β-CD (128.8 mg, 0.04 mmol) obtained in Initiator Preparation Example 4 was fed. As a monomer, n-butyl acrylate (hereinafter, abbreviated as BA) was added in an amount (33.59 g, 0.262 mol) 6 times greater than the required amount in order to prevent star coupling, and anisole solvent (47 g) was subsequently added. The mixture was bubbled with N 2 at 100 mL/min for 1 hour to remove oxygen in the system. Next, tin 2-ethylhexanoate Sn (EH)  2 reductant (0.136 g, 0.336 mmol) was added with a syringe to the flask in a nitrogen gas atmosphere to reduce the Cu catalyst complex, thereby initiating polymerization. Initiator/CuCl 2/Me6TREN/Sn (EH)  2 = 1/0.70/2.80/8.40 (by mol) . Here, the amount of BA, increased by 6 times, may be counted as an amount of solvent, and thus the solid concentration in the reaction liquid is calculated to be about 7%.
Next, the flask was tightly closed with a glass stopper and was soaked in an oil bath that had been set at 60℃, and the polymerization continued. The monomer conversion ratio and the molecular weight of the polymer were measured by GC  measurement and GPC measurement, respectively. When the BA conversion ratio approached 16.7%, the temperature was lowered and air was injected into the system to terminate the polymerization.
The polymer solution was transferred to a beaker soaked in an ice bath. Next, methanol was continuously dropped to the beaker while performing stirring until the solution became clouded, and a deposit was obtained. The dropping was stopped, and the solution was allowed to stand for a predetermined amount of time and was filtered to remove the liquid. Thus, an intermediate polymer 14Star-PBA was obtained that had the number of arms of 14, an arm length of about 5,000 and an arm composition of BA.
(Intermediate Polymer Preparation Example 7)
<Preparation of intermediate polymer having the number of arms of 14, an arm length of about 7,500 and an arm composition of BA>
CuCl 2·2H 2O catalyst (3.6 mg, 0.021 mmol) and Me6TREN (19.4 mg, 0.084 mmol) were dissolved into 1.0 g of DMF, and the solution was fed to a 100-ml four-necked flask. Next, 14Br-β-CD (120.8 mg, 0.0375 mmol) obtained in Initiator Preparation Example 4 was fed. As a monomer, n-butyl acrylate (hereinafter, abbreviated as BA) was added in an amount (19.67 g, 0.153 mol) 5 times greater than the  required amount in order to prevent star coupling, and anisole solvent (36 g) was subsequently added. The mixture was bubbled with N 2 at 100 mL/min for 1 hour to remove oxygen in the system. Next, tin 2-ethylhexanoate Sn (EH)  2 reductant (0.102 g, 0.252 mmol) was added with a syringe to the flask in a nitrogen gas atmosphere to reduce the Cu catalyst complex, thereby initiating polymerization. Initiator/CuCl 2/Me6TREN/Sn (EH)  2 = 1/0.56/2.24/6.72 (by mol) . Here, the amount of BA, increased by 5 times, may be counted as an amount of solvent, and thus the solid concentration in the reaction liquid is calculated to be about 7%.
Next, the flask was tightly closed with a glass stopper and was soaked in an oil bath that had been set at 60℃, and the polymerization continued. The monomer conversion ratio and the molecular weight of the polymer were measured by GC measurement and GPC measurement, respectively. When the BA conversion ratio approached 20%, the temperature was lowered and air was injected into the system to terminate the polymerization.
The polymer solution was transferred to a beaker soaked in an ice bath. Next, methanol was continuously dropped to the beaker while performing stirring until the solution became clouded, and a deposit was obtained. The dropping was stopped, and the solution was allowed to stand for a predetermined amount of time and was filtered to remove the  liquid. Thus, an intermediate polymer 14 Star-PBA was obtained that had the number of arms of 14, an arm length of about 7, 500 and an arm composition of BA.
(Intermediate Polymer Preparation Example 8)
<Preparation of intermediate polymer having the number of arms of 14, an arm length of about 10,000 and an arm composition of BA>
CuCl 2·2H 2O catalyst (6.3 mg, 0.037 mmol) and Me6TREN (34.2 mg, 0.112 mmol) were dissolved into 1.0 g of DMF, and the solution was fed to a 100-ml four-necked flask. Next, 14Br-β-CD (169.8 mg, 0.053 mmol) obtained in Initiator Synthesis Example 4 was fed. As a monomer, n-butyl acrylate (hereinafter, abbreviated as BA) was added in an amount (31.02 g, 0.242 mol) 6 times greater than the required amount in order to prevent star coupling, and anisole solvent (43 g) was subsequently added. The mixture was bubbled with N 2 at 100 mL/min for 1 hour to remove oxygen in the system. Next, tin 2-ethylhexanoate Sn (EH)  2 reductant (0.180 g, 0.445 mmol) was added with a syringe to the flask in a nitrogen gas atmosphere to reduce the Cu catalyst complex, thereby initiating polymerization. Initiator/CuCl 2/Me6TREN/Sn (EH)  2 = 1/0.7/2.8/8.4 (by mol) . Here, the amount of BA, increased by 6 times, may be counted as an amount of solvent, and thus the solid concentration in  the reaction liquid is calculated to be about 7%.
Next, the flask was tightly closed with a glass stopper and was soaked in an oil bath that had been set at 60℃, and the polymerization continued. The monomer conversion ratio and the molecular weight of the polymer were measured by GC measurement and GPC measurement, respectively. When the BA conversion ratio approached 25%, the temperature was lowered and air was injected into the system to terminate the polymerization.
The polymer solution was transferred to a beaker soaked in an ice bath. Next, methanol was continuously dropped to the beaker while performing stirring until the solution became clouded, and a deposit was obtained. The dropping was stopped, and the solution was allowed to stand for a predetermined amount of time and was filtered to remove the liquid. Thus, an intermediate polymer 14Star-PBA was obtained that had the number of arms of 14, an arm length of about 10,000 and an arm composition of BA.
(Example 1)
<Star-shaped polymer having the number of arms of 21, an arm length of about 10,000 and an arm composition of BA/MMA = 50/50 (by mass) >
4.724 g of the intermediate polymer obtained in Intermediate Polymer Preparation Example 1 was redissolved  into anisole, and the solution was transferred to a flask. Next, methyl methacrylate (hereinafter, abbreviated as MMA) was added to the flask in an amount 5 times greater than the required amount, namely, in an amount of 23.62 g (4.724 × 5) in order to prevent star coupling. Similarly to the BA polymerization described hereinabove, CuCl 2·2H 2O catalyst (5.4 mg, 0.032 mmol) and Me6TREN ligand (29.0 mg, 0.126 mmol) were added. Furthermore, a predetermined amount of anisole was added to control the solid concentration in the solution to less than 10%and thereby to prevent star coupling. After the mixture was bubbled with N 2, Sn (EH)  2 (0.1404 g, 0.347 mmol) was added and polymerization was initiated at 50℃. The polymerization was terminated when the MMA conversion ratio according to GC reached 20%.
The polymer solution was transferred to a beaker soaked in an ice bath. Next, methanol was continuously dropped to the beaker while performing stirring until the solution became clouded, and a deposit was obtained. The dropping was stopped, and the solution was allowed to stand for a predetermined amount of time and was filtered to remove the liquid. Thus, a star-shaped polymer Star-PBA-PMMA was obtained that had the number of arms of 21, an arm length of about 10,000 and an arm composition of BA/MMA = 50/50 (by mass) .
By GPC, the molecular weight of the star-shaped polymer  obtained was measured to be 185, 269. Because the number of initiation groups was 21, the arm length was calculated to be 8822. The star-shaped polymer obtained had an arm length close to the design (the designed arm length) .
The star-shaped polymer Star-PBA-PMMA obtained in Example 1 was analyzed by GPC. Fig. 1 illustrates GPC charts of 21Br-β-CD obtained in Initiator Preparation Example 1, Star-PBA obtained in Intermediate Polymer Preparation Example 1, and Star-PBA-PMMA obtained in Example 1. As illustrated in Fig. 1, the star-shaped polymer Star-PBA-PMMA of Example 1 had a unimodal peak, indicating that the star-shaped polymer was free from coupled stars.
(Example 2)
<Star-shaped polymer having the number of arms of 21, an arm length of about 10,000 and an arm composition of BA/MMA = 60/40 (by mass) >
4.935 g of the intermediate polymer obtained in Intermediate Polymer Preparation Example 2 was redissolved into anisole, and the solution was transferred to a flask. Next, MMA was added to the flask in an amount 7 times greater than the required amount, namely, in an amount of 23.03 g in order to prevent star coupling. Similarly to the BA polymerization described hereinabove, CuCl 2·2H 2O catalyst  (5.4 mg, 0.032 mmol) and Me6TREN ligand (29.0 mg, 0.126 mmol) were added. Furthermore, a predetermined amount of anisole was added to control the solid concentration in the solution to less than 10%and thereby to prevent star coupling. The solid concentration was thus controlled to 8%. After the mixture was bubbled with N 2, Sn (EH)  2 (0.1404 g, 0.347 mmol) was added and polymerization was initiated at 45℃. The polymerization was terminated when the MMA conversion ratio according to GC reached 14.3%.
The polymer solution was transferred to a beaker soaked in an ice bath. Next, methanol was continuously dropped to the beaker while performing stirring until the solution became clouded, and a deposit was obtained. The dropping was stopped, and the solution was allowed to stand for a predetermined amount of time and was filtered to remove the liquid. Thus, a star-shaped polymer Star-PBA-PMMA was obtained that had the number of arms of 21, an arm length of about 10,000 and an arm composition of BA/MMA = 60/40 (by mass) .
By GPC, the molecular weight of the star-shaped polymer obtained was measured to be 194, 783. Because the number of initiation groups was 21, the arm length was calculated to be 9,275. The star-shaped polymer obtained had an arm length close to the design.
The star-shaped polymer Star-PBA-PMMA obtained in Example 2 was analyzed by GPC. Fig. 2 illustrates GPC charts of 21Br-β-CD obtained in Initiator Preparation Example 1, Star-PBA obtained in Intermediate Polymer Preparation Example 2, and Star-PBA-PMMA obtained in Example 2. As illustrated in Fig. 2, the star-shaped polymer Star-PBA-PMMA of Example 2 had a unimodal peak, indicating that the star-shaped polymer was free from coupled stars.
(Example 3)
<Star-shaped polymer having the number of arms of 4, an arm length of about 10,000 and an arm composition of BA/MMA = 60/40 (by mass) >
4.048 g of the intermediate polymer obtained in Intermediate Polymer Preparation Example 3 was redissolved into anisole, and the solution was transferred to a flask. Next, MMA was added to the flask in an amount 3 times greater than the required amount, namely, in an amount of 8.04 g in order to prevent star coupling. Similarly to the BA polymerization described hereinabove, CuCl 2·2H 2O catalyst (4.6 mg, 0.027 mmol) and Me6TREN ligand (18.6 mg, 0.081 mmol) were added. Furthermore, a predetermined amount of anisole was added to control the solid concentration in the solution to less than 10%and thereby to prevent star coupling. The solid concentration was thus controlled to 8%.  After the mixture was bubbled with N 2, Sn (EH)  2 (0.1136 g, 0.336 mmol) was added and polymerization was initiated at 45℃. The polymerization was terminated when the MMA conversion ratio according to GC reached 33.3%.
The polymer solution was transferred to a beaker soaked in an ice bath. Next, methanol was continuously dropped to the beaker while performing stirring until the solution became clouded, and a deposit was obtained. The dropping was stopped, and the solution was allowed to stand for a predetermined amount of time and was filtered to remove the liquid. Thus, a star-shaped polymer Star-PBA-PMMA was obtained that had the number of arms of 4, an arm length of about 10,000 and an arm composition of BA/MMA = 60/40 (by mass) .
By GPC, the molecular weight of the star-shaped polymer obtained was measured to be 54, 516. Because the number of initiation groups was 4, the arm length was calculated to be 13,629. The star-shaped polymer obtained had an arm length close to the design.
The star-shaped polymer Star-PBA-PMMA obtained in Example 3 was analyzed by GPC. Fig. 3 illustrates GPC charts of 4Br-β-CD obtained in Initiator Preparation Example 2, Star-PBA obtained in Intermediate Polymer Preparation Example 3, and Star-PBA-PMMA obtained in Example 3. As  illustrated in Fig. 3, the star-shaped polymer Star-PBA-PMMA of Example 3 had a unimodal peak, indicating that the star-shaped polymer was free from coupled stars.
(Example 4)
<Star-shaped polymer having the number of arms of 7, an arm length of about 10,000 and an arm composition of BA/MMA = 60/40 (by mass) >
3.674 g of the intermediate polymer obtained in Intermediate Polymer Preparation Example 4 was redissolved into anisole, and the solution was transferred to a flask. Next, MMA was added to the flask in an amount 5 times greater than the required amount, namely, in an amount of 12.25 g in order to prevent star coupling. Similarly to the BA polymerization described hereinabove, CuCl 2·2H 2O catalyst (3.8 mg, 0.022 mmol) and Me6TREN ligand (15.3 mg, 0.067 mmol) were added. Furthermore, a predetermined amount of anisole was added to control the solid concentration in the solution to less than 10%and thereby to prevent star coupling. The solid concentration was thus controlled to 8%. After the mixture was bubbled with N 2, Sn (EH)  2 (0.140 g, 0.347 mmol) was added and polymerization was initiated at 45℃. The polymerization was terminated when the MMA conversion ratio according to GC reached 20%.
The polymer solution was transferred to a beaker soaked  in an ice bath. Next, methanol was continuously dropped to the beaker while performing stirring until the solution became clouded, and a deposit was obtained. The dropping was stopped, and the solution was allowed to stand for a predetermined amount of time and was filtered to remove the liquid. Thus, a star-shaped polymer Star-PBA-PMMA was obtained that had the number of arms of 7, an arm length of about 10,000 and an arm composition of BA/MMA = 60/40 (by mass) .
By GPC, the molecular weight of the star-shaped polymer obtained was measured to be 71, 340. Because the number of initiation groups was 7, the arm length was calculated to be 10,191. The star-shaped polymer obtained had an arm length close to the design.
The star-shaped polymer Star-PBA-PMMA obtained in Example 4 was analyzed by GPC. Fig. 4 illustrates GPC charts of 7Br-β-CD obtained in Initiator Preparation Example 3, Star-PBA obtained in Intermediate Polymer Preparation Example 4, and Star-PBA-PMMA obtained in Example 4. As illustrated in Fig. 4, the star-shaped polymer Star-PBA-PMMA of Example 4 had a unimodal peak, indicating that the star-shaped polymer was free from coupled stars.
(Example 5)
<Star-shaped polymer having the number of arms of 14, an arm length of about 10,000 and an arm composition of BA/MMA = 60/40 (by mass) >
4.479 g of the intermediate polymer obtained in Intermediate Polymer Preparation Example 5 was redissolved into anisole, and the solution was transferred to a flask. Next, MMA was added to the flask in an amount 5 times greater than the required amount, namely, in an amount of 14.93 g in order to prevent star coupling. Similarly to the BA polymerization described hereinabove, CuCl 2·2H 2O catalyst (3.8 mg, 0.022 mmol) and Me6TREN ligand (20.6 mg, 0.090 mmol) were added. Furthermore, a predetermined amount of anisole was added to control the solid concentration in the solution to less than 10%and thereby to prevent star coupling. The solid concentration was thus controlled to 8%. After the mixture was bubbled with N 2, Sn (EH)  2 (0.136 g, 0.336 mmol) was added and polymerization was initiated at 45℃. The polymerization was terminated when the MMA conversion ratio according to GC reached 20%.
The polymer solution was transferred to a beaker soaked in an ice bath. Next, methanol was continuously dropped to the beaker while performing stirring until the solution became clouded, and a deposit was obtained. The dropping was stopped, and the solution was allowed to stand for a predetermined amount of time and was filtered to remove the  liquid. Thus, a star-shaped polymer Star-PBA-PMMA was obtained that had the number of arms of 14, an arm length of about 10,000 and an arm composition of BA/MMA = 60/40 (by mass) .
By GPC, the molecular weight of the star-shaped polymer obtained was measured to be 118, 548. Because the number of initiation groups was 14, the arm length was calculated to be 8,468. The star-shaped polymer obtained had an arm length close to the design.
The star-shaped polymer Star-PBA-PMMA obtained in Example 5 was analyzed by GPC. Fig. 5 illustrates GPC charts of 14Br-β-CD obtained in Initiator Preparation Example 4, Star-PBA obtained in Intermediate Polymer Preparation Example 5, and Star-PBA-PMMA obtained in Example 5. As illustrated in Fig. 5, the star-shaped polymer Star-PBA-PMMA of Example 5 had a unimodal peak, indicating that the star-shaped polymer was free from coupled stars.
(Example 6)
<Star-shaped polymer having the number of arms of 14, an arm length of about 10,000 and an arm composition of BA/MMA = 50/50 (by mass) >
3.674 g of the intermediate polymer obtained in Intermediate Polymer Preparation Example 6 was redissolved  into anisole, and the solution was transferred to a flask. Next, MMA was added to the flask in an amount 4 times greater than the required amount, namely, in an amount of 14.69 g in order to prevent star coupling. Similarly to the BA polymerization described hereinabove, CuCl 2·2H 2O catalyst (3.8 mg, 0.022 mmol) and Me6TREN ligand (15.3 mg, 0.067 mmol) were added. Furthermore, a predetermined amount of anisole was added to control the solid concentration in the solution and thereby to prevent star coupling. The solid concentration was thus controlled to 14%. After the mixture was bubbled with N 2, Sn (EH)  2 (0.140 g, 0.347 mmol) was added and polymerization was initiated at 45℃. The polymerization was terminated when the MMA conversion ratio according to GC reached 20%.
The polymer solution was transferred to a beaker soaked in an ice bath. Next, methanol was continuously dropped to the beaker while performing stirring until the solution became clouded, and a deposit was obtained. The dropping was stopped, and the solution was allowed to stand for a predetermined amount of time and was filtered to remove the liquid. Thus, a star-shaped polymer Star-PBA-PMMA was obtained that had the number of arms of 14, an arm length of about 10,000 and an arm composition of BA/MMA = 50/50 (by mass) .
By GPC, the molecular weight of the star-shaped polymer  obtained was measured to be 102, 617. Because the number of initiation groups was 14, the arm length was calculated to be 7, 329. The star-shaped polymer obtained had an arm length close to the design.
The star-shaped polymer Star-PBA-PMMA obtained in Example 6 was analyzed by GPC. Fig. 6 illustrates GPC charts of 14Br-β-CD obtained in Initiator Preparation Example 4, Star-PBA obtained in Intermediate Polymer Preparation Example 6, and Star-PBA-PMMA obtained in Example 6. As illustrated in Fig. 6, the star-shaped polymer Star-PBA-PMMA of Example 6 had a unimodal peak, indicating that the star-shaped polymer was free from coupled stars.
(Example 7)
<Star-shaped polymer having the number of arms of 14, an arm length of about 15,000 and an arm composition of BA/MMA = 50/50 (by mass) >
4.003 g of the intermediate polymer obtained in Intermediate Polymer Preparation Example 7 was redissolved into anisole, and the solution was transferred to a flask. Next, MMA was added to the flask in an amount 6 times greater than the required amount, namely, in an amount of 24.02 g in order to prevent star coupling. Similarly to the BA polymerization described hereinabove, CuCl 2·2H 2O catalyst  (3.6 mg, 0.021 mmol) and Me6TREN ligand (19.4 mg, 0.084 mmol) were added. Furthermore, a predetermined amount of anisole was added to control the solid concentration in the solution and thereby to prevent star coupling. The solid concentration was thus controlled to 14%. After the mixture was bubbled with N 2, Sn (EH)  2 (0.140 g, 0.347 mmol) was added and polymerization was initiated at 45℃. The polymerization was terminated when the MMA conversion ratio according to GC reached 20%.
The polymer solution was transferred to a beaker soaked in an ice bath. Next, methanol was continuously dropped to the beaker while performing stirring until the solution became clouded, and a deposit was obtained. The dropping was stopped, and the solution was allowed to stand for a predetermined amount of time and was filtered to remove the liquid. Thus, a star-shaped polymer Star-PBA-PMMA was obtained that had the number of arms of 14, an arm length of about 15,000 and an arm composition of BA/MMA = 50/50 (by mass) .
By GPC, the molecular weight of the star-shaped polymer obtained was measured to be 165, 687. Because the number of initiation groups was 14, the arm length was calculated to be 11,834. The star-shaped polymer obtained had an arm length close to the design.
The star-shaped polymer Star-PBA-PMMA obtained in Example 7 was analyzed by GPC. Fig. 7 illustrates GPC charts of 14Br-β-CD obtained in Initiator Preparation Example 4, Star-PBA obtained in Intermediate Polymer Preparation Example 7, and Star-PBA-PMMA obtained in Example 7. As illustrated in Fig. 7, the high-molecular region indicated the presence of slight star coupling in the star-shaped polymer Star-PBA-PMMA of Example 7, but the amount of coupled stars in the star-shaped polymer was very small.
(Example 8)
<Star-shaped polymer having the number of arms of 14, an arm length of about 20,000 and an arm composition of BA/MMA = 50/50 (by mass) >
4.479 g of the intermediate polymer obtained in Intermediate Polymer Preparation Example 8 was redissolved into anisole, and the solution was transferred to a flask. Next, MMA was added to the flask in an amount 7 times greater than the required amount, namely, in an amount of 31.35 g in order to prevent star coupling. Similarly to the BA polymerization described hereinabove, CuCl 2·2H 2O catalyst (3.8 mg, 0.022 mmol) and Me6TREN ligand (20.6 mg, 0.090 mmol) were added. Furthermore, a predetermined amount of anisole was added to control the solid concentration in the solution and thereby to prevent star coupling. The solid  concentration was thus controlled to 12%. After the mixture was bubbled with N 2, Sn (EH)  2 (0.136 g, 0.336 mmol) was added and polymerization was initiated at 45℃. The polymerization was terminated when the MMA conversion ratio according to GC reached 20%.
The polymer solution was transferred to a beaker soaked in an ice bath. Next, methanol was continuously dropped to the beaker while performing stirring until the solution became clouded, and a deposit was obtained. The dropping was stopped, and the solution was allowed to stand for a predetermined amount of time and was filtered to remove the liquid. Thus, a star-shaped polymer Star-PBA-PMMA was obtained that had the number of arms of 14, an arm length of about 20,000 and an arm composition of BA/MMA = 50/50 (by mass) .
By GPC, the molecular weight of the star-shaped polymer obtained was measured to be 223, 139. Because the number of initiation groups was 14, the arm length was calculated to be 15,939. The star-shaped polymer obtained had an arm length close to the design.
The star-shaped polymer Star-PBA-PMMA obtained in Example 8 was analyzed by GPC. Fig. 8 illustrates GPC charts of 14Br-β-CD obtained in Initiator Preparation Example 4, Star-PBA obtained in Intermediate Polymer  Preparation Example 8, and Star-PBA-PMMA obtained in Example 8. As illustrated in Fig. 8, the high-molecular region indicated the presence of slight star coupling in the star-shaped polymer Star-PBA-PMMA of Example 8, but the amount of coupled stars in the star-shaped polymer was very small.
(Comparative Example 1)
<Star-shaped polymer prepared by one-pot synthesis without using macroinitiator>
CuCl 2·2H 2O catalyst (10.4 mg, 0.06 mmol) and Me6TREN (41.2 mg, 0.18 mmol) were dissolved into 1.0 g of DMF, and the solution was fed to a 100-ml four-necked flask. Next, 14Br-β-CD (400.5 mg, 0.125 mmol) obtained in Initiator Preparation Example 4 was fed. As a monomer, n-butyl acrylate (hereinafter, abbreviated as BA) was added in an amount required (21.0 g, 0.163 mol) , and anisole solvent (84 g) was subsequently added. The mixture was bubbled with N 2 at 100 mL/min for 1 hour to remove oxygen in the system. Next, tin 2-ethylhexanoate Sn (EH)  2 reductant (0.2429 g, 0.6 mmol) was added with a syringe to the flask in a nitrogen gas atmosphere to reduce the Cu catalyst complex, thereby initiating polymerization. Initiator/CuCl 2/Me6TREN/Sn (EH)  2 = 1/0.48/1.44/4.8 (by mol) . Here, the solid concentration in the reaction liquid is calculated to be about 20%.
Next, the flask was tightly closed with a glass stopper  and was soaked in an oil bath that had been set at 80℃, and the polymerization continued. The monomer conversion ratio and the molecular weight of the polymer were measured by GC measurement and GPC measurement, respectively. The reaction was continued for 11 hours until the BA conversion ratio reached nearly 100%.
Next, MMA was added in a required amount of 14 g to the flask. Furthermore, anisole was added to control the solid concentration to 20%. The reaction was continued at 70℃ for 11 hours until the MMA conversion ratio reached nearly 100%.
The polymer solution was transferred to a beaker soaked in an ice bath. Next, methanol was continuously dropped to the beaker while performing stirring until the solution became clouded, and a deposit was obtained. The dropping was stopped, and the solution was allowed to stand for a predetermined amount of time and was filtered to remove the liquid, thereby recovering a polymer. A star-shaped polymer Star-PBA-PMMA of Comparative Example 1 was thus obtained.
The star-shaped polymer Star-PBA-PMMA obtained in Comparative Example 1 was analyzed by GPC. Fig. 9 illustrates GPC charts of 14Br-β-CD obtained in Initiator Preparation Example 4, 14 Star-PBA before the addition of MMA, and Star-PBA-PMMA obtained in Comparative Example 1. As  illustrated in Fig. 9, the star-shaped polymer Star-PBA-PMMA of Comparative Example 1 had bimodal peak, indicating a significant occurrence of star coupling. The GPC molecular weights and the arm lengths of the star-shaped polymer obtained are described in Table 1. The arm lengths calculated from the molecular weight of each of the bimodal distribution were far different from the designed arm length of 20,000.
(Reference Example 1)
<Study of BA conversion ratio>
CuCl 2·2H 2O catalyst and Me6TREN in the same amounts as in Comparative Example 1 were dissolved into 1.0 g of DMF, and the solution was fed to a 100-ml four-necked flask. Next, the CD skeleton-containing initiator 7Br-β-CD from Initiator Preparation Example 3 that had 7 initiation points was fed in the same amount as in Comparative Example 1. BA was added in an amount (8.62 g, 0.0672 mol) 1.6 times greater than the required amount in order to prevent star coupling, and anisole solvent (48 g) was subsequently added. The mixture was bubbled with N 2 at 100 mL/min for 1 hour to remove oxygen in the system. Next, tin 2-ethylhexanoate reductant Sn (EH)  2 was added in the same amount as in Comparative Example 1 with a syringe to the flask in a nitrogen gas atmosphere to reduce the Cu catalyst complex,  thereby initiating polymerization. Initiator/CuCl 2/Me6TREN/Sn (EH)  2 = 1/0.48/21.44/4.8 (by mol) . Here, the amount of BA, increased by 1.6 times, may be counted as an amount of solvent, and thus the solid concentration in the reaction liquid is calculated to be about 10%.
Next, the flask was tightly closed with a glass stopper and was soaked in an oil bath that had been set at 70℃, and the polymerization continued. The monomer conversion ratio and the molecular weight of the polymer were measured by GC measurement and GPC measurement, respectively. The reaction was continued for 3 hours until the BA conversion ratio reached 62%.
The star-shaped polymer Star-PBA obtained in Reference Example 1 was analyzed by GPC. Fig. 10 illustrates a GPC chart of Star-PBA obtained in Reference Example 1. As illustrated in Fig. 10, the star-shaped polymer Star-PBA of Reference Example 1 had bimodal peak, indicating a significant occurrence of star coupling.
(Reference Example 2)
<Study of MMA conversion ratio>
CuCl 2·2H 2O catalyst (3.9 mg, 0.022 mmol) and Me6TREN (14.6 mg, 0.064 mmol) were dissolved into 1.0 g of DMF, and  the solution was fed to a 100-ml four-necked flask. Next, 4Br-β-CD (242.4 mg, 0.14 mmol) obtained in Initiator Preparation Example 2 was fed. As a monomer, MMA was added to the flask in an amount 2.4 times greater than the required amount, namely, in an amount of 4.07 g. CuCl 2·2H 2O catalyst (4.6 mg, 0.027 mmol) and Me6TREN ligand (18.6 mg, 0.081 mmol) were added. Furthermore, a predetermined amount of anisole was added to control the solid concentration in the solution to less than 10%and thereby to prevent star coupling. The solid concentration was thus controlled to 8%. After the mixture was bubbled with N 2, Sn (EH)  2 (0.1136 g, 0.336 mmol) was added and polymerization was initiated at 45℃. The polymerization was terminated when the degree of MMA reaction according to GC reached 43%.
Star-PMMA obtained in Reference Example 2 was analyzed by GPC. Fig. 11 illustrates a GPC chart of Star-PMMA obtained in Reference Example 2. The star-shaped polymer Star-PMMA of Reference Example 2 had a broad distribution, indicating an occurrence of star coupling.
[Film preparation, tensile test: methods for measuring maximum point stress and elongation]
The star-shaped polymers obtained in Examples and Comparative Example were each adjusted to a solid  concentration of 15 mass%. 6.0 g of the 15 mass%solution of the star-shaped polymer was uniformly poured to a PFA Petri dish having a diameter of 10 cm, and was dried at 120℃ to form a 0.1 mm thick film. The film obtained was cut to give a test piece having a width of 5 mm and a length of 5 cm. The maximum point stress and the elongation were measured by evaluating tensile characteristics with a tensile tester (TENSILON RTG1310, manufactured by A&D Company, Limited) . The results are described in Table 1. The results of the tensile test of Examples 2 to 5 are illustrated in Fig. 12, and the results of the tensile test of Examples 6 to 8 are illustrated in Fig. 13.
[Table 1]
Figure PCTCN2022107909-appb-000007
*: Arm length calculated from Mw of the star-shaped polymer on the low-molecular weight side in the bimodal distribution  GPC result
**: Arm length calculated from Mw of the star-shaped polymer on the high-molecular weight side in the bimodal distribution GPC result
#: Mw of the star-shaped polymer on the low-molecular weight side in the bimodal distribution GPC result
##: Mw of the star-shaped polymer on the high-molecular weight side in the bimodal distribution GPC result
The results of the GPC measurement indicated that the star-shaped polymers obtained in Examples 1 to 8 had a very small amount of coupled stars. Furthermore, the star-shaped polymers obtained in Examples 1 to 8 exhibited a high maximum point stress and a large elongation in the tensile test, and thus had excellent mechanical properties. In contrast, the star-shaped polymer of Comparative Example 1, which was obtained by one-pot synthesis without using any macroinitiators, exhibited a low maximum point stress and a small elongation in the tensile test, and compared unfavorably to Examples in mechanical properties.

Claims (12)

  1. A method for producing a star-shaped polymer that includes
    a core portion, and
    an arm portion being a polymer chain bonded to the core portion, the arm portion including a first block and a second block, the first block being located on a side of the polymer chain adjacent to the core portion and bonded to the core portion, the second block being located on a tip side of the polymer chain, the method comprising:
    a step of preparing an intermediate polymer by performing living radical polymerization of a monofunctional vinyl compound as a first block constituent component in presence of a catalyst while using as an initiator a cyclodextrin skeleton-containing compound having polymerization initiation groups serving as initiation points for polymerization, to prepare an intermediate polymer including the core portion and a plurality of the first blocks each including a structural unit derived from the monofunctional vinyl compound and bonded to an initiation point of the core portion; and
    a step of preparing a star-shaped polymer by performing living radical polymerization of a monofunctional vinyl compound as a second block constituent component in presence  of a catalyst while using the intermediate polymer as a macroinitiator, to prepare a star-shaped polymer including the core portion, the first blocks, and a plurality of the second blocks each including a structural unit derived from the monofunctional vinyl compound and bonded to the first block.
  2. The method for producing a star-shaped polymer according to claim 1, wherein the star-shaped polymer has 4 or more and 21 or less arm portions.
  3. The method for producing a star-shaped polymer according to claim 1, wherein in the step of preparing an intermediate polymer, the living radical polymerization is performed until a monomer conversion ratio of the monofunctional vinyl compound as the first block constituent component reaches 10%or more and 60%or less.
  4. The method for producing a star-shaped polymer according to claim 1, wherein in the step of preparing a star-shaped polymer, the living radical polymerization is performed until a monomer conversion ratio of the monofunctional vinyl compound as the second block constituent component reaches 10%or more and 40%or less.
  5. The method for producing a star-shaped polymer according to claim 1, wherein the living radical polymerization in the step of preparing an intermediate polymer and in the step of preparing a star-shaped polymer is atom transfer radical polymerization.
  6. The method for producing a star-shaped polymer according to claim 1, wherein
    the monofunctional vinyl compound as the first block constituent component is a (meth) acrylic acid compound, and
    the monofunctional vinyl compound as the second block constituent component is a (meth) acrylic acid compound.
  7. The method for producing a star-shaped polymer according to claim 1, wherein a mass ratio of the first block to the second block (first block: second block) is 30: 70 to 70: 30.
  8. The method for producing a star-shaped polymer according to claim 1, wherein the polymerization initiation groups are α-haloacyloxy groups or α-haloacyl groups.
  9. The method for producing a star-shaped polymer according to claim 1, wherein the cyclodextrin skeleton-containing compound is a compound represented by following  formula (1) :
    [Chem. 1]
    Figure PCTCN2022107909-appb-100001
    where R 1 independently denotes a hydrogen atom or a 2-bromoisobutyryl group, and *denotes a bond.
  10. A star-shaped polymer produced by the method for producing a star-shaped polymer according to any one of claims 1 to 9.
  11. A paint comprising the star-shaped polymer according to claim 10.
  12. A coating formed from the paint according to claim 11.
PCT/CN2022/107909 2022-07-26 2022-07-26 Star-shaped polymer, paint, coating, and method for producing star-shaped polymer WO2024020780A1 (en)

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