Vinyl polymer and method for producing the same

Abstract

Provided are vinyl polymers comprising a polymer (P1) represented by formula (1) and a polymer (P2) represented by formula (2), the content of the polymer (P2) being 10 mol% or less with respect to the sum of the polymer (P1) and the polymer (P2). In each of the formulae, R1 and R3 each represent, for example, a hydrogen atom, a chlorine atom, or any of alkyl, aryl, aralkyl, heterocyclyl, alkoxy, and alkylthio groups in each of which any hydrogen atom bonded to a carbon atom may have been replaced, R2 represents a substituted or unsubstituted divalent aromatic hydrocarbon group, and A indicates a polymer chain having a structural unit derived from a vinyl monomer.

Description

Cross - reference to related applications

[0001] This application is based on Japanese Patent Application No. 2020 - 134917 filed on August 7, 2020, the contents of which are incorporated herein by reference.

Technical Field

[0002] The present disclosure relates to a vinyl - based polymer and a method for producing the same.

Background Art

[0003] As living radical polymerization methods, various polymerization methods are known, such as reversible addition - fragmentation chain transfer polymerization (RAFT method), nitroxide radical method (NMP method), atom transfer radical polymerization (ATRP method), polymerization method using an organic tellurium compound (TERP method), polymerization method using an organic antimony compound (SBRP method), polymerization method using an organic bismuth compound (BIRP method), and iodine transfer polymerization method. Among these, from the viewpoints of polymerization controllability and ease of implementation, the RAFT method, NMP method, and ATRP method are industrially used. In particular, the RAFT method can be applied to the widest range of vinyl monomers and is attracting attention as a metal - free polymerization method. Vinyl - based polymers obtained by the RAFT method are being studied for various applications such as paints and adhesives.

[0004] In the RAFT method, in the presence of a polymerization regulator (RAFT agent) having a thiocarbonylthio group, such as a dithioester compound, xanthate compound, trithiocarbonate compound, dithiocarbamate compound, etc., and a general free - radical polymerization initiator, the polymerization proceeds through a reversible chain - transfer reaction.

[0005] As a vinyl - based polymer obtained by the RAFT method, for example, Patent Document 1 discloses a polyacrylate ester produced by living radical polymerization using a compound having two dithioester groups (1,4 - bis(phenylthiocarbonylsulfanylmethyl)benzene) as a RAFT agent having two thiocarbonylthio groups.

[0006] In addition, Non-Patent Document 1 discloses a polyacrylate ester produced by living radical polymerization using a compound having two trithiocarbonate groups (1,4-bis(n-butylsulfanylthiocarbonylsulfanylmethyl)benzene) as a RAFT agent having two thiocarbonylthio groups.

Prior Art Documents

Patent Documents

[0007]

Patent Document 1

Non-Patent Documents

[0008]

Non-Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0009] The polyacrylate esters disclosed in Patent Document 1 and Non-Patent Document 1 have insufficient heat resistance (especially heat resistance under high temperature conditions of more than 150°C), and there is room for further improvement.

[0010] This disclosure has been made in view of the above circumstances, and its object is to provide a vinyl polymer excellent in heat resistance.

Means for Solving the Problems

[0011] As a result of intensive studies to solve the above problems, the present inventors have found that a polymer having a specific structural formula is contained in a vinyl polymer obtained by living radical polymerization using a RAFT agent, and that containing more of the polymer of the specific structural formula than a predetermined amount is the cause of the decrease in heat resistance when the vinyl polymer is placed under high-temperature conditions. Based on this finding, the present inventors have completed the present disclosure. Specifically, the following means are provided according to the present disclosure.

[0012] 〔1〕 A vinyl polymer containing a polymer (P1) represented by the following formula (1) and a polymer (P2) represented by the following formula (2), wherein the content of the polymer (P2) is 10 mol% or less with respect to the total amount of the polymer (P1) and the polymer (P2).

Chemical formula

[0013] 〔2〕 The vinyl polymer according to 〔1〕, wherein at least one of the R 1 and the R 3 is a substituted or unsubstituted alkylthio group. [3] The vinyl monomer is a vinyl polymer of [1] or [2] containing a (meth)acrylic compound.

[0014] [4] A method for producing a vinyl polymer by a living radical polymerization method, comprising a step of polymerizing a vinyl monomer using a RAFT agent containing a compound (R1) represented by the following formula (3) and a compound (R2) represented by the following formula (4), wherein the content of the compound (R2) in the RAFT agent is 10 mol% or less based on the total amount of the compound (R1) and the compound (R2). A method for producing a vinyl polymer. [Chemical formula] (In formula (3) and formula (4), R 1 and R 3 each independently represents a hydrogen atom, a chlorine atom, an alkyl group, an aryl group, an aralkyl group, a heterocyclyl group, an alkoxy group, an alkylthio group, a dialkoxyphosphino group, an alkoxycarbonyl group, "-O-Ar 1 ", "-S-Ar 1 " or "-NR 4 R 5 " (where Ar 1 is an aryl group or an aralkyl group, and R 4 and R 5 are each independently a monovalent hydrocarbon group), and any hydrogen atom bonded to a carbon atom may be substituted. R 2 represents a substituted or unsubstituted divalent aromatic hydrocarbon group.) [Advantages of the Invention]

[0015] According to the present disclosure, a vinyl polymer excellent in heat resistance can be obtained. [Embodiments for Carrying Out the Invention]

[0016] Hereinafter, the present disclosure will be described in detail. In this specification, “(meth)acryl” means acrylic and / or methacrylic, and “(meth)acrylate” means acrylate and / or methacrylate. Further, “(meth)acrylo” means acrylo and / or methacrylo.

[0017] 《Vinyl Polymer》 The vinyl polymer of the present disclosure (hereinafter also referred to as “vinyl polymer (P)”) includes a polymer (P1) which is a vinyl polymer represented by the following formula (1) and a polymer (P2) which is a vinyl polymer represented by the following formula (2). In the vinyl polymer (P), the content of the polymer (P2) is 10 mol% or less with respect to the total amount (100 mol%) of the polymer (P1) and the polymer (P2). [Chemical Formula] (In Formula (1) and Formula (2), R 1 and R 3 each independently represent a hydrogen atom, a chlorine atom, an alkyl group, an aryl group, an aralkyl group, a heterocyclyl group, an alkoxy group, an alkylthio group, a dialkoxyphosphino group, an alkoxycarbonyl group, “-O-Ar 1 ”, “-S-Ar 1 ” or “-NR 4 R 5 ” (wherein Ar 1 is an aryl group or an aralkyl group, and R 4 and R 5 are each independently a monovalent hydrocarbon group), and any hydrogen atom bonded to a carbon atom may be substituted. R 2 represents a substituted or unsubstituted divalent aromatic hydrocarbon group. A represents a polymer chain having a structural unit derived from a vinyl monomer).

[0018] In the above Formula (1) and Formula (2), R 1 and R 3As specific examples, as the alkyl group, for example, a methyl group, an ethyl group, a propyl group, a butyl group, a pentyl group, a hexyl group, a heptyl group, an octyl group, a nonyl group, a decyl group, an undecyl group, a dodecyl group, a tetradecyl group, a hexadecyl group, an octadecyl group, a nonadecyl group, etc. may be mentioned. These may be linear or branched.

[0019] As the aryl group, a phenyl group, a tolyl group, a xylyl group, a 1-naphthyl group, a 2-naphthyl group, etc. may be mentioned. As the aralkyl group, a benzyl group, a phenethyl group, etc. may be mentioned. As the heterocyclyl group, a 1-pyrrolyl group, a 1-imidazolyl group, a 2-oxo-1-pyrrolidinyl group, a phthalimide group, etc. may be mentioned. As the alkoxy group, a methoxy group, an ethoxy group, a propoxy group, etc. may be mentioned.

[0020] As the alkylthio group, a methylthio group, an ethylthio group, a propylthio group, a butylthio group, a pentylthio group, a hexylthio group, a heptylthio group, an octylthio group, a nonylthio group, a decylthio group, an undecylthio group, a dodecylthio group, a tetradecylthio group, a hexadecylthio group, an octadecylthio group, a nonadecylthio group, etc. may be mentioned.

[0021] As the dialkoxyphosphino group, a dimethoxyphosphino group, a diethoxyphosphino group, a methoxyethoxyphosphino group, etc. may be mentioned. As the alkoxycarbonyl group, a methoxycarbonyl group, an ethoxycarbonyl group, etc. may be mentioned.

[0022] Groups represented by "-O-Ar 1 " include a phenoxy group, a benzyloxy group, etc. Groups represented by "-S-Ar 1 " include a phenylsulfide group, a benzylsulfide group, etc. Groups represented by "-NR 4 R 5 " include an N,N-dimethylamino group, an N,N-diethylamino group, an N-methyl-N-ethylamino group, an N-phenyl-N-methylamino group, an N-phenyl-N-ethylamino group, etc. R 1and R 3 When having a substituent, examples of the substituent include a halogen atom (such as a fluorine atom, a chlorine atom, a bromine atom, an iodine atom, etc.), a cyano group, and the like.

[0023] R 1 and R 3 are preferably monovalent groups having 1 to 20 carbon atoms. Among these, in terms of having a high migration constant and excellent polymerization controllability, at least one of R 1 and R 3 is preferably a substituted or unsubstituted alkylthio group, and it is more preferable that both R 1 and R 3 are substituted or unsubstituted alkylthio groups.

[0024] R 2 is preferably a divalent group having 6 to 20 carbon atoms. Specific examples of R 2 include a substituted or unsubstituted phenylene group, a group represented by “-R 6 -B 1 -R 7 -” (wherein R 6 and R 7 are each independently an alkylene group having 1 to 5 carbon atoms, and B 1 is a substituted or unsubstituted phenylene group). When a substituent is introduced into the phenylene group, examples of the substituent include an alkyl group (such as a methyl group or an ethyl group) and a halogen atom. R 2 is preferably, from the viewpoint of polymerization activity, “-CH2-phenylene group-CH2-”, “-CH(CH3)-phenylene group-CH(CH3)-”, or “-C(CH3)2-phenylene group-C(CH3)2-”.

[0025] In the above formulas (1) and (2), A is a polymer chain having a structural unit derived from a vinyl monomer. The polymer chains of the vinyl polymer (P) (that is, the polymer chains of the polymers (P1) and (P2)) are constituted by A in the above formulas (1) and (2). As the vinyl monomer constituting the polymer chain, various vinyl monomers having radical polymerizability can be used. Examples of the vinyl monomer include (meth)acrylate compounds, aromatic vinyl compounds, unsaturated carboxylic acids, unsaturated acid anhydrides, hydroxy group-containing vinyl compounds, amino group-containing vinyl compounds, amide group-containing vinyl compounds, alkoxy group-containing vinyl compounds, nitrile group-containing vinyl compounds, maleimide compounds, and the like. As the vinyl monomer, one of these may be used alone, or two or more thereof may be used in combination.

[0026] Specific examples of the vinyl monomer include, as the (meth)acrylate compound, (meth)acrylic acid methyl, (meth)acrylic acid ethyl, (meth)acrylic acid n-propyl, (meth)acrylic acid isopropyl, (meth)acrylic acid n-butyl, (meth)acrylic acid isobutyl, (meth)acrylic acid tert-butyl, (meth)acrylic acid n-pentyl, (meth)acrylic acid amyl, (meth)acrylic acid n-hexyl, (meth)acrylic acid n-octyl, (meth)acrylic acid ethylhexyl, (meth)acrylic acid n-dodecyl, (meth)acrylic acid n-octadecyl and other (meth)acrylic acid alkyl ester compounds; (meth)acrylic acid cyclohexyl, (meth)acrylic acid methylcyclohexyl, (meth)acrylic acid tert-butylcyclohexyl, (meth)acrylic acid cyclododecyl, (meth)acrylic acid isobornyl, (meth)acrylic acid adamantyl, (meth)acrylic acid dicyclopentenyl, (meth)acrylic acid dicyclopentanyl and other (meth)acrylic acid aliphatic cyclic ester compounds; Examples include aromatic ester compounds of (meth)acrylic acid such as phenyl methacrylate, (meth)acrylic acid benzyl, (meth)acrylic acid phenoxymethyl, 2-phenoxyethyl (meth)acrylate, 3-phenoxypropyl (meth)acrylate, and the like.

[0027] Examples of the aromatic vinyl compound include styrene-based compounds such as styrene, α-methylstyrene, β-methylstyrene, vinylxylene, o-methylstyrene, m-methylstyrene, p-methylstyrene, o-ethylstyrene, m-ethylstyrene, p-ethylstyrene, p-n-butylstyrene, p-isobutylstyrene, p-t-butylstyrene, o-methoxystyrene, m-methoxystyrene, p-methoxystyrene, o-chlorostyrene, m-chlorostyrene, p-chlorostyrene, p-hydroxystyrene, m-hydroxystyrene, o-hydroxystyrene, p-isopropenylphenol, m-isopropenylphenol, o-isopropenylphenol, o-vinylbenzoic acid, m-vinylbenzoic acid, p-vinylbenzoic acid, and divinylbenzene, and vinylnaphthalene.

[0028] Examples of the unsaturated carboxylic acid include (meth)acrylic acid, maleic acid, fumaric acid, itaconic acid, crotonic acid, citraconic acid, cinnamic acid, and monoalkyl esters of unsaturated dicarboxylic acids (such as monoalkyl esters of maleic acid, fumaric acid, itaconic acid, and citraconic acid). Examples of the unsaturated acid anhydride include maleic anhydride, itaconic anhydride, and citraconic anhydride.

[0029] Examples of the hydroxy group-containing vinyl compound include hydroxyalkyl (meth)acrylate compounds such as 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 3-hydroxypropyl (meth)acrylate, 2-hydroxybutyl (meth)acrylate, 3-hydroxybutyl (meth)acrylate, and 4-hydroxybutyl (meth)acrylate; polyalkylene glycol mono(meth)acrylate compounds such as polyethylene glycol mono(meth)acrylate, polypropylene glycol mono(meth)acrylate, and polyethylene glycol-polypropylene glycol mono(meth)acrylate; unsaturated alcohols such as allyl alcohol; N-substituted maleimide compounds such as N-(4-hydroxyphenyl)maleimide; and hydroxyl group-containing styrene compounds such as o-hydroxystyrene, m-hydroxystyrene, and p-hydroxystyrene.

[0030] Examples of the amino group-containing vinyl compound include dimethylaminomethyl (meth)acrylate, diethylaminomethyl (meth)acrylate, 2-dimethylaminoethyl (meth)acrylate, 2-diethylaminoethyl (meth)acrylate, 2-(di-n-propylamino)ethyl (meth)acrylate, 2-dimethylaminopropyl (meth)acrylate, 2-diethylaminopropyl (meth)acrylate, 2-(di-n-propylamino)propyl (meth)acrylate, 3-dimethylaminopropyl (meth)acrylate, 3-diethylaminopropyl (meth)acrylate, and 3-(di-n-propylamino)propyl (meth)acrylate.

[0031] Examples of the amide group-containing vinyl compound include (meth)acrylamide, N,N-dimethyl(meth)acrylamide, N,N-dimethylaminopropyl(meth)acrylamide, N-methylol(meth)acrylamide and the like. Examples of the alkoxy group-containing vinyl compound include, for example, 2-methoxyethyl (meth)acrylate, 2-ethoxyethyl (meth)acrylate, 2-(n-propoxy)ethyl (meth)acrylate, 2-(n-butoxy)ethyl (meth)acrylate, 3-methoxypropyl (meth)acrylate, 3-ethoxypropyl (meth)acrylate, 2-(n-propoxy)propyl (meth)acrylate, 2-(n-butoxy)propyl (meth)acrylate and the like.

[0032] Examples of the nitrile group-containing vinyl compound include cyanomethyl (meth)acrylate, 1-cyanoethyl (meth)acrylate, 2-cyanoethyl (meth)acrylate, 1-cyanopropyl (meth)acrylate, 2-cyanopropyl (meth)acrylate, 3-cyanopropyl (meth)acrylate, 4-cyanobutyl (meth)acrylate, 6-cyanohexyl (meth)acrylate, 2-ethyl-6-cyanohexyl (meth)acrylate, 8-cyanooctyl (meth)acrylate, (meth)acrylonitrile, α-ethylacrylonitrile, α-isopropylacrylonitrile, α-chloroacrylonitrile, α-fluoroacrylonitrile and the like.

[0033] Examples of the maleimide compound include maleimide and N-substituted maleimide compounds. Examples of the N-substituted maleimide compounds include N-alkyl-substituted maleimide compounds such as N-methylmaleimide, N-ethylmaleimide, N-n-propylmaleimide, N-isopropylmaleimide, N-n-butylmaleimide, N-isobutylmaleimide, N-tert-butylmaleimide, N-pentylmaleimide, N-hexylmaleimide, N-heptylmaleimide, N-octylmaleimide, N-laurylmaleimide, and N-stearylmaleimide; N-cycloalkyl-substituted maleimide compounds such as N-cyclopentylmaleimide and N-cyclohexylmaleimide; N-aralkyl-substituted maleimide compounds such as N-benzylmaleimide; and N-aryl-substituted maleimide compounds such as N-phenylmaleimide, N-(4-hydroxyphenyl)maleimide, N-(4-acetylphenyl)maleimide, N-(4-methoxyphenyl)maleimide, N-(4-ethoxyphenyl)maleimide, N-(4-chlorophenyl)maleimide, and N-(4-bromophenyl)maleimide. In the production of the vinyl polymer (P), in addition to the above compounds, dialkyl esters of unsaturated dicarboxylic acids, vinyl ester compounds, vinyl ether compounds, etc. can also be used.

[0034] Among these monomers constituting the polymer chain of the vinyl polymer (P), (meth)acrylic compounds are preferably included, and particularly preferably, a compound represented by the following formula (5) is included, because the vinyl polymer (P) can be produced relatively easily by the living radical polymerization method and the degree of freedom in the selection of the monomers is high. CH2=CR 8 -C(=O)-O-(R 9 O)n-R 10 …(5) (In formula (5), R 8 represents a hydrogen atom or a methyl group, R 9 represents a linear or branched alkylene group having 2 to 6 carbon atoms, R 10represents a hydrogen atom, an alkyl group having 1 to 20 carbon atoms, a cycloalkyl group having 3 to 20 carbon atoms, an aryl group having 6 to 20 carbon atoms, or an aralkyl group having 7 to 20 carbon atoms. n represents an integer of 0 to 100.)

[0035] Specific examples of the compound represented by the above formula (5) include the (meth)acrylate compounds, alkoxy group-containing vinyl compounds, hydroxyalkyl (meth)acrylate compounds, and polyalkylene glycol mono(meth)acrylate compounds exemplified above. Among these, it is more preferable to contain a (meth)acrylate compound in that a vinyl polymer (P) having various excellent properties such as heat resistance can be obtained. In the compound represented by the above formula (5), the group "-(R 9 O)n-R 10 " in the above formula (5) preferably has 2 or more carbon atoms, and more preferably 3 or more carbon atoms. Regarding the upper limit of the carbon number of the group "-(R 9 O)n-R 10 ", from the viewpoint of maintaining polymerization controllability, it is preferably 10 or less, and more preferably 8 or less.

[0036] Among the monomers constituting the polymer chain of the vinyl polymer (P), the amount of the (meth)acrylic compound is preferably 50 mol% or more, more preferably 70 mol% or more, still more preferably 80 mol% or more, and even more preferably 90 mol% or more with respect to the total amount of the monomers constituting the polymer chain.

[0037] The vinyl polymer (P) is a mixture of a polymer (P1) and a polymer (P2). More specifically, the vinyl polymer (P) has the polymer (P1) as the main component and contains the polymer (P2) as an impurity. In the vinyl polymer (P), when the content of the polymer (P2) is 10 mol% or less based on the total amount (100 mol%) of the polymer (P1) and the polymer (P2), a vinyl polymer excellent in heat resistance under more severe high-temperature conditions can be obtained. From such a viewpoint, the content of the polymer (P2) in the vinyl polymer (P) is preferably 9.5 mol% or less, more preferably 9.2 mol% or less, still more preferably 9.0 mol% or less, and even more preferably 8.5 mol% or less with respect to the total amount of the polymer (P1) and the polymer (P2). The lower limit of the content of the polymer (P2) is not particularly limited, but from the viewpoint of ease of production, it is, for example, 0.01 mol% or more, preferably 0.05 mol% or more, and more preferably 0.1 mol% or more with respect to the total amount of the polymer (P1) and the polymer (P2).

[0038] In this specification, the impurity (i.e., the polymer (P2)) contained in the vinyl polymer (P) can be identified by the method shown below. First, for the vinyl polymer (P), gel permeation chromatography (GPC) fractionation is performed under the conditions described in the examples below, and the fraction on the high molecular weight side obtained is concentrated to obtain a concentrate. Subsequently, 1 1H-NMR measurement is performed, and it is identified from the ratio of the integral values of the proton peaks derived from R 1 , R 2 and R 3 in the above formulas (1) and (2), and the proton peak on the polymer chain carbon adjacent to the thiocarbonylthio group (i.e., the proton peak derived from the polymer chain A). In the case of the polymer (P2), with respect to the integral value of the proton peak derived from R 2 , R 1 and R 3The integral value of the proton peak of the origin is observed to be 0.5 times each compared to the polymer (P1), and the integral value of the proton peak on the polymer chain carbon adjacent to the thiocarbonylthio group is observed to be equal. By utilizing this, it is possible to confirm that the structure of the compound in the high molecular weight side fraction obtained by GPC fractionation is the structure of the polymer (P2).

[0039] Regarding the "structural unit derived from the vinyl monomer" of the vinyl polymer (P), it can be analyzed by pyrolysis gas chromatography / mass spectrometry (pyrolysis GC / MS). Regarding the "RAFT agent" used in the synthesis of the vinyl polymer (P), it can be analyzed by pyrolysis GC / MS and matrix-assisted laser desorption ionization method (MALDI-TOF / MS).

[0040] The content of the polymer (P2) in the vinyl polymer (P) can be calculated by the method shown below. First, perform GPC measurement of the vinyl polymer (P) under the conditions described in the examples below to obtain a GPC chart in which the peak intensity is plotted against LogM (M is the molecular weight). Let the peak start point be A and the end point be B, and vertically divide the peaks on the high molecular weight side and the low molecular weight side that appear in the GPC chart (let each LogM at the time of vertical division be X), and from the peak intensity Y(n) and molecular weight M(n) for each LogM, calculate the content (mol%) of the polymer (P2) in the vinyl polymer (P) from the following formula (6). Note that "Y(n) / M(n)" represents the number of moles (mol).

Equation

[0041] <Production of Vinyl Polymer (P)> The vinyl polymer (P) can be obtained by polymerizing vinyl monomers by a living radical polymerization method. For example, in the case of a solution polymerization method, an organic solvent and a monomer are charged into a reactor, a radical polymerization initiator is added, and preferably heated and copolymerized to obtain the target vinyl polymer (P). The charging method of each raw material may be a batch-type initial batch charging method in which all raw materials are charged at once, a semi-continuous charging method in which at least a part of the raw materials are continuously supplied into the reactor, or a continuous polymerization method in which all raw materials are continuously supplied and the product is continuously withdrawn from the reactor at the same time. Among the polymerization methods used to obtain the vinyl polymer (P), the reversible addition-fragmentation chain transfer polymerization method (RAFT method) is preferable.

[0042] In the RAFT method, polymerization proceeds through a reversible chain transfer reaction in the presence of a polymerization controller (RAFT agent) and a free radical polymerization initiator. When producing the vinyl polymer (P) by the RAFT method, the vinyl polymer (P) can be produced by a method including a step of polymerizing vinyl monomers using a RAFT agent containing a compound (R1) represented by the following formula (3) and a compound (R2) represented by the following formula (4).

Chemical formula

[0043] In addition, for the specific examples of R 1 , R 2 , R 3 in the above formulas (3) and (4), the descriptions of R 1 , R 2 , R 3 in the above formulas (1) and (2) can be cited. Specific examples of the compound (R1) and the compound (R2) include the above R 1 , R 2 , R 3Examples of each of these can be combined arbitrarily to give compounds of structural formulas. The compound (R1) and the compound (R2) are preferably trithiocarbonate compounds in that they have high mobility constants and are excellent in the controllability of polymerization.

[0044] In the production of the vinyl polymer (P), specifically, as the RAFT agent, a RAFT agent mainly composed of the compound (R1) and containing the compound (R2) as an impurity can be used. When a mixture of the compound (R1) and the compound (R2) is used as the RAFT agent, the content of the compound (R2) in the RAFT agent is preferably 10 mol% or less with respect to the total amount (100 mol%) of the compound (R1) and the compound (R2) from the viewpoint of obtaining a vinyl polymer excellent in heat resistance. From the above viewpoint, the content of the compound (R2) is more preferably 9.5 mol% or less, still more preferably 9.2 mol% or less, even more preferably 9.0 mol% or less, and particularly preferably 8.5 mol% or less with respect to the total amount of the compound (R1) and the compound (R2). Regarding the lower limit of the content of the compound (R2) in the RAFT agent, there is no particular limitation, but from the viewpoint of the availability of the RAFT agent, it is, for example, 0.01 mol% or more, preferably 0.05 mol% or more, and more preferably 0.1 mol% or more with respect to the total amount of the compound (R1) and the compound (R2).

[0045] The content of the compound (R2) in the RAFT agent can be adjusted, for example, by subjecting the mixture of the compound (R1) and the compound (R2) to a purification treatment. The purification method is not particularly limited, and examples thereof include recrystallization, reprecipitation, extraction, sublimation, chromatography, column adsorption, and the like. At this time, the content of the compound (R2) in the RAFT agent can be adjusted by appropriately selecting the number of purification times and the purification method. From the viewpoint of obtaining a vinyl polymer excellent in heat resistance under higher temperature conditions (for example, conditions higher than 150 °C), the number of purification times for purifying the mixture of the compound (R1) and the compound (R2) is preferably plural. When purification is performed a plurality of times, the purification method for each time may be the same or different.

[0046] In addition, the identification and calculation of the content of the compound (R2) contained in the RAFT agent can be carried out 1 by 1H-NMR measurement. That is, 1 According to the 1H-NMR measurement, R in the above formulas (3) and (4) 1 , R 2 and R 3 Only the proton peaks derived from can be observed. Therefore, the structures of the RAFT agent and the compound (R2) can be determined by using these proton peaks.

[0047] Also, the content of the compound (R2) in the RAFT agent is the case where the integral value of the proton peak (a) derived from R 2 is normalized to 1, R 1 and R 3 It can be calculated from the integral value of the proton peak (b) derived from. Specifically, when the RAFT agent contains the compound (R2) as an impurity, the R in the above formula (4) 2 The integral value of the proton peak (a) derived from is the integral value of the proton peaks (b) derived from R 1 and R 3 Is observed at 0.5 times that of the compound (R1). That is, when the integral value of the proton peak (a) derived from R 2 is normalized to 1, R 1 and R 3 Let the integral value of the proton peak (b) derived from be Ib, and the mol ratio of the compound (R1) in the RAFT agent be α and the mol ratio of the compound (R2) be β. The following two mathematical formulas represent the established relationship. α + β = 1 (integral value of (a) normalized to 1) α + 0.5β = Ib (integral value of (b) when the integral value of (a) is normalized to 1) Therefore, by solving this system of simultaneous equations to obtain α and β, the content of the compound (R2) in the RAFT agent can be calculated.

[0048] As radical polymerization initiators used in polymerization by the RAFT method, known radical polymerization initiators such as azo compounds, organic peroxides, and persulfates can be used. Among these, azo compounds are preferred in terms of being easy to handle in terms of safety and having few side reactions during radical polymerization. Specific examples of azo compounds include 2,2'-azobis(isobutyronitrile), 2,2'-azobis(2,4-dimethylvaleronitrile), 2,2'-azobis(4-methoxy-2,4-dimethylvaleronitrile), dimethyl-2,2'-azobis(2-methylpropionate), 2,2'-azobis(2-methylbutyronitrile), 1,1'-azobis(cyclohexane-1-carbonitrile), 2,2'-azobis[N-(2-propenyl)-2-methylpropionamide], 2,2'-azobis(N-butyl-2-methylpropionamide), and the like. As the radical polymerization initiator, only one kind may be used, or two or more kinds may be used in combination.

[0049] The amount of the radical polymerization initiator used is not particularly limited, but from the viewpoint of obtaining a polymer with a smaller molecular weight distribution, it is preferably 0.5 mol or less, more preferably 0.2 mol or less, per 1 mol of the RAFT agent. Also, from the viewpoint of stably performing the polymerization reaction, the lower limit of the amount of the radical polymerization initiator used is preferably 0.01 mol or more, more preferably 0.05 mol or more, per 1 mol of the RAFT agent. The amount of the radical polymerization initiator used per 1 mol of the RAFT agent is preferably 0.01 to 0.5 mol, more preferably 0.05 to 0.2 mol.

[0050] The coincidence reaction is preferably carried out in a polymerization solvent known in living radical polymerization in the solvent. The polymerization solvent to be used is preferably an organic solvent capable of dissolving the monomer, for example, aromatic compounds such as benzene, toluene, xylene and anisole; ester compounds such as methyl acetate, propyl acetate and butyl acetate; ketone compounds such as acetone, methyl ethyl ketone and cyclohexanone, and the like. In addition, the polymerization solvent may be used alone or in combination of two or more. Further, when a hydrophilic monomer is used, alcohol, water or the like can be used as the polymerization solvent. The amount of the polymerization solvent used is preferably 5 to 200 parts by mass, more preferably 10 to 100 parts by mass, based on 100 parts by mass of the total amount of the monomers used in the reaction. When the amount of the polymerization solvent used is 100 parts by mass or less, it is preferable in that a high polymerization rate can be achieved in a short time.

[0051] In the polymerization reaction by the RAFT method, the reaction temperature is preferably 40 °C or higher and 100 °C or lower, more preferably 45 °C or higher and 90 °C or lower, and still more preferably 50 °C or higher and 80 °C or lower. When the reaction temperature is 40 °C or higher, it is preferable in that the polymerization reaction can proceed smoothly, and when the reaction temperature is 100 °C or lower, it is preferable in that side reactions can be suppressed and the restrictions on the initiators and solvents that can be used are relaxed. Further, the reaction time can be appropriately set according to the monomers used, etc., but it is preferably 1 hour or more and 48 hours or less, more preferably 2 hours or more and 24 hours or less. The polymerization reaction may be carried out in the presence of a chain transfer agent such as an alkylthiol compound having 2 to 20 carbon atoms, if necessary. When a polymer solution containing a vinyl polymer (P) is obtained by the above polymerization, the vinyl polymer (P) can be isolated by performing a known solvent removal treatment on this polymer solution.

[0052] Regarding the obtained vinyl polymer (P), the number average molecular weight (Mn) in terms of polystyrene measured by gel permeation chromatography (GPC) is preferably in the range of 2,000 to 1,000,000. When Mn is 2,000 or more, it is preferable in that it becomes possible to express the desired properties in the vinyl polymer (P). Also, when Mn is 1,000,000 or less, it is preferable in that sufficient processability such as coatability and handleability can be ensured. The Mn of the vinyl polymer (P) is more preferably 5,000 or more, still more preferably 8,000 or more, and particularly preferably 10,000 or more. Regarding the upper limit of Mn of the vinyl polymer (P), it is more preferably 800,000 or less, still more preferably 700,000 or less, even more preferably 600,000 or less, and particularly preferably 500,000 or less. The preferable range of Mn of the vinyl polymer (P) can be determined by appropriately combining the above-mentioned upper and lower limits. The Mn of the vinyl polymer (P) is more preferably in the range of 5,000 to 800,000, still more preferably in the range of 8,000 to 700,000, and even more preferably in the range of 10,000 to 600,000.

[0053] The weight average molecular weight (Mw) in terms of polystyrene measured by GPC of the vinyl polymer (P) is preferably in the range of 2,000 to 1,000,000. The Mw of the vinyl polymer (P) is more preferably 5,000 or more, still more preferably 8,000 or more, and particularly preferably 10,000 or more. Regarding the upper limit of Mw of the vinyl polymer (P), it is more preferably 800,000 or less, still more preferably 700,000 or less, even more preferably 600,000 or less, and particularly preferably 500,000 or less. The range of Mw of the vinyl polymer (P) is more preferably in the range of 5,000 to 800,000, still more preferably in the range of 8,000 to 700,000, and even more preferably in the range of 10,000 to 600,000.

[0054] The molecular weight distribution (Mw / Mn) of the vinyl polymer (P) is preferably 3.0 or less from the viewpoint of achieving better heat resistance. The molecular weight distribution (Mw / Mn) is more preferably 2.5 or less, and still more preferably 2.0 or less. The lower limit of the molecular weight distribution (Mw / Mn) is not particularly limited, but is, for example, 1.01 or more from the viewpoint of ease of production.

[0055] The vinyl polymer (P) obtained by this production method can be used in a wide range of applications. Specifically, for example, it can be applied to various applications such as dispersants, industrial rubbers, binders, adhesives, paints, coating agents, surfactants, etc. Further, examples of the application fields include automotive parts, home appliance and OA equipment parts, medical equipment parts, packaging materials, civil engineering and construction materials, electric wires, sundries, etc.

Examples

[0056] Hereinafter, the present disclosure will be specifically described by way of examples, but the present disclosure is not limited to these examples. In the following, "parts" and "%" mean "parts by mass" and "mass %", respectively, unless otherwise specified.

[0057] The method for measuring the molecular weight of the polymer is as follows. <Molecular weight measurement> For the obtained vinyl polymer, gel permeation chromatography (GPC) measurement was performed under the following conditions to obtain the number average molecular weight (Mn) and weight average molecular weight (Mw) in terms of polystyrene. Further, the molecular weight distribution (Mw / Mn) was calculated from the obtained values of Mn and Mw. ○ Measurement conditions Column: 4 columns of TSKgel SuperMultipore HZ-M manufactured by Tosoh Corporation Solvent: Tetrahydrofuran Temperature: 40 °C Detector: RI Flow rate: 600 μL / min The evaluation method of the vinyl polymer in Examples and Comparative Examples is as follows.

[0058] <Identification of Impurities Contained in Vinyl Polymer> The impurities contained in the vinyl polymer were identified by the method shown below. First, GPC fractionation was carried out under the following conditions, and the fraction on the high molecular weight side obtained was concentrated. ○GPC Fractionation Conditions Column: Shim-pack GPC-2001C × 1 piece + Shim-pack GPC-20025C × 1 piece (20 mm ID × 30 cm) manufactured by Shimadzu Corporation Solvent: Chloroform Temperature: 40 °C Detector: RI Flow rate: 3.0 mL / min Next, for the obtained concentrate, 1 1H-NMR measurement was performed, and from the integral values of the proton peaks derived from the terminal methyl group of the lauryl group ((A) in the following formula, 0.9 ppm), the proton peak on the polymer chain carbon adjacent to the thiocarbonylthio group ((B) in the following formula, 4.9 ppm), and the proton peak derived from the benzene ring ((C) in the following formula, 7.2 ppm), the impurities contained in the vinyl polymer were identified. That is, if the concentrate (impurity) of the fraction on the high molecular weight side has the structure of the following polymer (1), the ratio of the integral values of (A) / (B) / (C) is 6 / 2 / 4, and if it has the structure of polymer (2), the ratio of (A) / (B) / (C) is 6 / 4 / 8. [Chemical formula] (In the formula, n is an integer.)

[0059] <Content of Polymer (2) in Vinyl Polymer> From the GPC measurement results in the above molecular weight measurement of the obtained vinyl polymer, a GPC chart was obtained in which the peak intensity was plotted against LogM. The peak start point was designated as A and the peak end point as B, and the peak on the high molecular weight side and the peak on the low molecular weight side were vertically divided (let each LogM at this time be X). From the peak intensity Y and the molecular weight M for each LogM, the content (mol%) of the vinyl polymer (2) in the vinyl polymer was calculated from the following formula. In the following formula, the denominator represents the number of molecules of the peak between the peak start point A and the end point B, and the numerator represents the number of molecules of the high molecular weight peak. [Equation]

[0060] [Heat resistance] 30 ml of the obtained vinyl polymer was placed in a screw tube bottle, put into an explosion-proof dryer at 170 °C, and the sample was taken out after 500 hours. The weight average molecular weight was determined by GPC measurement, and the heat resistance was evaluated by the change rate of the weight average molecular weight calculated by the following formula. The closer the value of the change rate is to 1.0, the better the heat resistance can be said to be. Change rate = [Mw after 500 hours from the start of applying the heat load] / [Mw before applying the heat load]

[0061] [Synthesis Example 1] (Synthesis of RAFT Agent 1) To a eggplant-shaped flask, 1-dodecanethiol (42.2 g), 20% KOH aqueous solution (63.8 g), and trioctylmethylammonium chloride (1.5 g) were added and cooled in an ice bath. Carbon disulfide (15.9 g) and tetrahydrofuran (hereinafter also referred to as "THF") (38 ml) were added and stirred for 20 minutes. A THF solution (170 ml) of α,α'-dichloro-p-xylene (16.6 g) was added dropwise over 30 minutes. After reacting at room temperature for 1 hour, it was extracted from chloroform, washed with pure water, dried over anhydrous sodium sulfate, and concentrated with a rotary evaporator. The obtained crude product was purified by silica gel column chromatography. As a result of identifying the obtained compound (RAFT Agent 1) by LC / MS measurement, it was found to be a mixture of the compound of the following structural formula (1) and the compound of structural formula (2). [Chemical formula]

[0062] 1 From the 1H-NMR measurement, the quantification of the compound of structural formula (1) and the compound of structural formula (2) in RAFT agent 1 was carried out. Specifically, for the integral value of the proton peak derived from the benzene ring ((a) in structural formula (1) and structural formula (2), 7.2 ppm) and the integral value of the proton peak derived from the methylene group ((b) in structural formula (1) and structural formula (2), 3.4 ppm), when the integral value of (a) was normalized to 1, it was calculated by using the integral value of (b) when the integral value of (a) was normalized to 1. For RAFT agent 1 1 The ratio of the integral values of each proton peak obtained from the 1H-NMR measurement of RAFT agent 1 was (a) / (b) = 1 / 0.85.

[0063] Also, assuming that the mole ratio of the compound of structural formula (1) in RAFT agent 1 is α and the mole ratio of the compound of structural formula (2) is β, the following mathematical formulas (6) and (7) are established. α + β = 1 …(6) α + 0.5β = 0.85 …(7) Note that mathematical formula (6) represents the integral value of (a) normalized to 1, and mathematical formula (7) represents the integral value of (b) when the integral value of (a) is normalized to 1. By solving this system of simultaneous equations to obtain α and β, the content of the compound of structural formula (2) was calculated to be 30 mol%.

[0064] [Purification Example 1] (Preparation of RAFT agent 2) Ethyl acetate was added to the product (RAFT agent 1) obtained by the same operation as in Synthesis Example 1 above in an amount of 30 ml / g, heated to 60 °C, and after the product was completely dissolved, it was left standing at room temperature overnight for purification by recrystallization to obtain RAFT agent 2 with a content of the compound of structural formula (2) of 15 mol%.

[0065] [Purification Example 2] (Preparation of RAFT agent 3) By performing the same operation as in Purification Example 1 and subjecting RAFT agent 2 to recrystallization from ethyl acetate once, RAFT agent 3 with a content of the compound of Structural Formula (2) of 10 mol% was obtained.

[0066] [Purification Example 3] (Preparation of RAFT agent 4) By performing the same operation as in Purification Example 1 and subjecting RAFT agent 3 to recrystallization from ethyl acetate once, RAFT agent 4 with a content of the compound of Structural Formula (2) of 6.0 mol% was obtained.

[0067] [Production Example 1] (Production of vinyl polymer I) Into a 1 L flask equipped with a stirrer and a thermometer, RAFT agent 4 (2.15 g), 2,2'-azobis(2-methylbutyronitrile) (hereinafter also referred to as "ABN-E") (0.13 g), n-butyl acrylate (hereinafter also referred to as "BA") (417.7 g), and anisole (280.0 g) were charged, thoroughly degassed by nitrogen bubbling, and polymerization was initiated in a constant temperature bath at 70°C. After 4 hours, it was cooled to room temperature to stop the reaction. The above polymerization solution was purified by reprecipitation from methanol and dried under vacuum to obtain vinyl polymer I. The molecular weight of the obtained vinyl polymer I was Mn 68,000, Mw 76,000, and Mw / Mn 1.12 as measured by GPC (polystyrene conversion).

[0068] Also, when the impurities contained in vinyl polymer I were identified by the above method, the ratio of the integral values of (A) / (B) / (C) in the concentrate of the high molecular fraction was 6 / 4 / 8. From this result, it was found that the impurities had the structure of polymer (2). Furthermore, when the content of polymer (2) in vinyl polymer I was calculated, it was calculated to be 5.0 mol% based on the total amount of 100 mol% of polymer (1) and polymer (2).

[0069] [Production Example 2 and Comparative Production Examples 1 and 2] (Production of vinyl polymers II, III, and IV) The same operation as in Production Example 1 was performed except that RAFT agent 4 was changed to RAFT agents 3, 2, and 1 respectively to obtain vinyl polymers II, III, and IV. The molecular weights of the respective vinyl polymers and the content of polymer (2) in the vinyl polymers are shown in Table 1.

[0070]

Table 1

[0071] The details of the compounds shown in Table 1 are as follows. BA: n-Butyl acrylate ABN-E: 2,2’-Azobis(2-methylbutyronitrile)

[0072] [Examples 1, 2 and Comparative Examples 1, 2] The heat resistance of the vinyl polymers I, II, III, and IV obtained in each production example was evaluated. The results are shown in Table 2.

[0073]

Table 2

[0074] As is clear from the evaluation results, with respect to a total of 100 mol% of the polymers (1) and (2), the vinyl polymers I and II in which the content of the polymer (2) was 10 mol% or less were excellent in heat resistance under high temperature conditions of 170°C for 500 hours. In contrast, the vinyl polymers III and IV in which the content of the polymer (2) exceeded 10 mol% were inferior in heat resistance to the vinyl polymers I and II.

[0075] Although the present disclosure has been described based on the examples, it is understood that the present disclosure is not limited to the examples and structures. The present disclosure includes various modifications and modifications within the equivalent range. In addition, various combinations and forms, and further, other combinations and forms including only one element, more than one element, or less than one element thereof, are within the scope and spirit of the present disclosure.

Claims

1. It contains a polymer (P1) represented by the following formula (1) and a polymer (P2) represented by the following formula (2), A vinyl polymer in which the content of the polymer (P2) is 10 mol% or less with respect to the total amount of the polymer (P1) and the polymer (P2). 【Chemical 1】 (In Formula (1) and Formula (2), R １ and R ３ each independently represents a hydrogen atom, a chlorine atom, an alkyl group, an aryl group, an aralkyl group, a heterocyclyl group, an alkoxy group, an alkylthio group, a dialkoxyphosphino group, an alkoxycarbonyl group, "-O-Ar １ ", "-S-Ar １ ", or "-NR ４ R ５ " (where Ar １ represents an aryl group or an aralkyl group, and R ４ and R ５ each independently represent a monovalent hydrocarbon group), and any hydrogen atom bonded to a carbon atom may be substituted. R ２ represents a substituted or unsubstituted divalent aromatic hydrocarbon group. A represents a polymer chain having a structural unit derived from a vinyl monomer.)

2. Said R １ and said R ３ At least one of which is a substituted or unsubstituted alkylthio group, the vinyl polymer according to claim 1.

3. The vinyl monomer contains a (meth)acrylic compound. The vinyl polymer according to Claim 1 or 2.

4. A method for producing a vinyl polymer by a living radical polymerization method, It includes a step of polymerizing a vinyl monomer using a RAFT agent containing a compound (R1) represented by the following formula (3) and a compound (R2) represented by the following formula (4), A method for producing a vinyl polymer, wherein the content of the compound (R2) in the RAFT agent is 10 mol% or less with respect to the total amount of the compound (R1) and the compound (R2). [Chemical 2] (In formulas (3) and (4), R １ and R ３ each independently represents a hydrogen atom, a chlorine atom, an alkyl group, an aryl group, an aralkyl group, a heterocyclyl group, an alkoxy group, an alkylthio group, a dialkoxyphosphino group, an alkoxycarbonyl group, "-O-Ar １ ", "-S-Ar １ " or "-NR ４ R ５ " (where Ar １ is an aryl group or an aralkyl group, and R ４ and R ５ are each independently a monovalent hydrocarbon group), and any hydrogen atom bonded to a carbon atom may be substituted. R ２ represents a substituted or unsubstituted divalent aromatic hydrocarbon group.)

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