JP5649309B2 - Method for producing styrenic polymer - Google Patents

Description

  The present invention relates to a method for producing a styrene polymer having a number average molecular weight of 30,000 or more.

  In general, when anionic polymerization of a styrene monomer having a number average molecular weight of less than 30000, a mixed solvent in which a low polarity solvent such as toluene or hexane and an ether group-containing polar solvent such as tetrahydrofuran are mixed at an arbitrary ratio, It is known that polymers having a narrow molecular weight distribution (Mw / Mn) can be produced.

  On the other hand, an additive capable of controlling the polymerization reaction by adding it to the reaction system of the anionic polymerization reaction is known. For example, in Non-Patent Document 1, when a styrene monomer is polymerized in a tetrahydrofuran solvent at −78 ° C., side reaction derived from the side chain portion can be suppressed by adding t-butoxy potassium. It is disclosed. In Non-Patent Document 1, a polymer having a number average molecular weight of 9240 to 61400 is produced with narrow dispersion (molecular weight distribution: 1.02 to 1.06).

Monatshefte fur Chemie 2006, 137, 855-867

It was difficult to industrially produce a styrene polymer having a molecular weight of 30,000 or more and a molecular weight distribution (Mw / Mn) of 1.01 to 1.30 by conventional techniques.
As described above, according to the method described in Non-Patent Document 1, a styrene polymer having a number average molecular weight of up to about 60000 can be produced in a tetrahydrofuran dispersion in a tetrahydrofuran solvent. However, the production method disclosed in Non-Patent Document 1 is an excellent method for precise polymerization on a small scale, but as a method for industrially producing a high molecular weight styrene polymer, It was not possible to adopt.
A problem arises when a high molecular weight styrene polymer is industrially produced by anionic polymerization in a tetrahydrofuran solvent. In a tetrahydrofuran solvent, since the stability of the polymer anion is low, it is easily deactivated during the polymerization reaction. Therefore, it has been difficult to produce a high molecular weight and narrowly dispersed polymer.

In general, it is known that the stability of a polymer anion is improved in a low polarity solvent such as toluene than in a polar solvent such as tetrahydrofuran.
Therefore, when the anionic polymerization reaction is carried out in a tetrahydrofuran solvent containing 50% by weight or more of toluene, the stability of the polymer anion can be improved. However, in such a solvent system, the rate of the polymerization reaction becomes very slow. Even when the reaction is not completed or when the reaction is completed, it takes a long time. As a result, it is difficult to obtain a desired high molecular weight polymer by narrow dispersion.
In addition, when the content of toluene is 50% or less, the stability of the polymer anion is insufficient, and in this case as well, it is difficult to obtain a desired high molecular weight and narrow molecular weight distribution polymer. .

  As a result of intensive studies to solve the above problems, the present inventors have found that a specific organic potassium compound increases the reaction rate of the polymer anion in a solvent system containing 50% by weight or more of a nonpolar or low polarity solvent. As a result, the present invention has been completed.

（式中、Ｒ^１は、水素原子又はアルキル基を表し、Ｒ^２は、アルキル基、アルコキシ基、ｔ−ブトキシカルボニル基、ｔ−ブトキシカルボニルメチル基、又はテトラヒドロピラニル基を表す。ｐが２以上の場合、同一又は相異なっていてもよい。ｐは０〜５の整数を表す。）で表される化合物であることを特徴とする（１）又は（２）に記載のスチレン系重合体の製造方法や、
（４）非極性又は低極性溶媒が芳香族炭化水素系溶媒であることを特徴とする（１）〜（３）のいずれかに記載のスチレン系重合体の製造方法や、
（５）極性溶媒がエーテル系溶媒であることを特徴とする（１）〜（４）のいずれかに記載のスチレン系重合体の製造方法に関する。 That is, the present invention
(1) A styrene monomer in a mixed solvent composed of 50 to 95% by weight of a nonpolar or low polarity solvent and 50 to 5% by weight of a polar solvent in the presence of an organic potassium compound at a temperature of -100 to -30 ° C. Wherein the number average molecular weight is 30000 or more and the molecular weight distribution (Mw / Mn) is 1.01 to 1.30,
(2) The organic potassium compound has the formula [I]
R-O ^- K ⁺ [I]
Wherein R is an alkyl group, a cycloalkyl group, an alkylsulfonyl group, an arylsulfonyl group, a heteroarylsulfonyl group, an alkylcarbonyl group, an arylcarbonyl group, a heteroarylcarbonyl group, an aryl group, a heteroaryl group, an aralkyl group or Represents a heteroaralkyl group.)
The method for producing a styrenic polymer according to (1), which is a compound represented by:
(3) The styrene monomer is represented by the formula [II]

(In the formula, R ¹ represents a hydrogen atom or an alkyl group, and R ² represents an alkyl group, an alkoxy group, a t-butoxycarbonyl group, a t-butoxycarbonylmethyl group, or a tetrahydropyranyl group. P is 2. In these cases, they may be the same or different, and p represents an integer of 0 to 5.) The styrenic polymer as described in (1) or (2) Manufacturing method,
(4) The method for producing a styrenic polymer according to any one of (1) to (3), wherein the nonpolar or low polarity solvent is an aromatic hydrocarbon solvent,
(5) The method for producing a styrene polymer according to any one of (1) to (4), wherein the polar solvent is an ether solvent.

  According to the method for producing a polymer of the present invention, a high molecular weight and narrowly dispersed styrene polymer can be produced by anionic polymerization in a solvent system containing 50% by weight or more of a nonpolar or low polarity solvent.

The meanings of terms used in the present specification are described below, and the present invention is described in more detail.
“Alkyl group” means a C1-C20 linear or branched alkyl group. Examples thereof include a methyl group, an ethyl group, a propyl group, an isopropyl group, a butyl group, an isobutyl group, a sec-butyl group, a tert-butyl group, a pentyl group, an isopentyl group, a hexyl group, an isohexyl group, and an octyl group.
The “alkoxy group” means a C1-C20 linear or branched alkoxy group, for example, a methoxy group, an ethoxy group, a propoxy group, an isopropoxy group, a butoxy group, a sec-butoxy group, an isobutoxy group, Examples thereof include a tert-butoxy group, a pentyloxy group, an isopentyloxy group, a hexyloxy group, and isohexyloxy.
Examples of the “aryl group” include phenyl, naphthyl and the like.

The “heteroaryl group” is a 5-membered or 6-membered single atom containing 1 or 2 and preferably 1 to 4 heteroatoms selected from the group consisting of oxygen atom, nitrogen atom and sulfur atom. A cyclic heteroaryl or a condensed cyclic heteroaryl in which the monocyclic heteroaryl and the aryl are condensed or the same or different monocyclic heteroaryl is condensed with each other, such as pyrrolyl, furyl, thienyl, imidazolyl, Pyrazolyl, thiazolyl, isothiazolyl, oxazolyl, isoxazolyl, triazolyl, tetrazolyl, oxadiazolyl, 1,2,3-thiadiazolyl, 1,2,4-thiadiazolyl, 1,3,4-thiadiazolyl, pyridyl, pyrazinyl, pyrimidinyl, pyridazinyl, 1, 2,4-triazini 1,3,5-triazinyl, indolyl, benzofuranyl, benzothienyl, benzimidazolyl, benzopyrazolyl, benzoxazolyl, benzisoxazolyl, benzothiazolyl, benzoisothiazolyl, indazolyl, purinyl, quinolyl, isoquinolyl, phthalazinyl, naphthyridinyl Quinoxanyl, quinazolinyl, cinnolinyl, pteridinyl, pyrido [3,2-b] pyridyl and the like.
The “cycloalkyl group” means a C3 to C8 cycloalkyl group, and examples thereof include a cyclopropyl group, a cyclobutyl group, a cyclopentyl group, and a cyclohexyl group.
The “alkylsulfonyl group” is a group in which the alkyl group is bonded to sulfonyl, and examples thereof include methylsulfonyl, ethylsulfonyl, n-propylsulfonyl and the like.

The “arylsulfonyl group” is a group in which the aryl group is bonded to sulfonyl, and examples thereof include phenylsulfonyl and naphthylsulfonyl.
The “heteroarylsulfonyl group” is a group in which the heteroaryl group is bonded to sulfonyl, and examples thereof include pyrrolylsulfonyl, furylsulfonyl, thienylsulfonyl, imidazolylsulfonyl and the like.
The “aralkyl group” means a group in which the aryl and the alkyl are bonded, and examples thereof include benzyl, 1-phenylethyl, 2-phenylethyl, 1-naphthylmethyl, 2-naphthylmethyl and the like.
The “heteroaralkyl group” means a group in which the heteroaryl and the alkyl are bonded, and examples thereof include pyrrolylmethyl, furylmethyl, thienylethyl, imidazolylethyl and the like.
The “alkylcarbonyl group” is a group in which the alkyl group is bonded to carbonyl, and examples thereof include acetyl, propionyl, isobutyryl, valeryl, isovaleryl, pivaloyl and the like.
The “arylcarbonyl group” is a group in which the aryl is bonded to carbonyl, and examples thereof include benzoyl and naphthylcarbonyl.
The “heteroarylcarbonyl group” is a group in which the heteroaryl group is bonded to carbonyl, and examples thereof include pyrrolylcarbonyl, pyridylcarbonyl, thienylcarbonyl, and the like.

(Method for producing styrene polymer)
The method for producing a polymer of the present invention comprises the presence of an organic potassium compound represented by the formula [I] in a mixed solvent composed of 50 to 95% by weight of a nonpolar or low polarity solvent and 50 to 5% by weight of a polar solvent. Below, the styrene monomer is polymerized at a temperature of -100 to -30 ° C.

  The nonpolar or low polarity solvent of the present invention is an aliphatic hydrocarbon solvent such as hexane or heptane, an aromatic hydrocarbon solvent such as benzene or toluene, or an alicyclic hydrocarbon solvent such as cyclohexane or cycloheptane. A solvent can be illustrated. Of these, aromatic hydrocarbon solvents are preferred, and toluene is more preferred. Moreover, these solvent can be used individually by 1 type or as a 2 or more types of mixed solvent.

  Examples of the polar solvent of the present invention include ether solvents such as diethyl ether, tetrahydrofuran (THF), dioxane and trioxane, and tertiary amines such as tetramethylethylenediamine and hexamethylphosphoric triamide. Of these, ether solvents are preferred, and tetrahydrofuran is more preferred. Moreover, these solvent can be used individually by 1 type or as a 2 or more types of mixed solvent.

  In the present invention, a mixed solvent of a nonpolar or low polarity solvent and a polar solvent is used. The mixed solvent used in the present invention is preferably a solvent system in which a nonpolar or low polarity solvent is mixed at 50 to 95% by weight and a polar solvent is mixed at 50 to 5% by weight, and the nonpolar or low polarity solvent is 50 to 80% by weight. A solvent system in which a polar solvent is mixed at 50 to 20% by weight is more preferable. Specifically, a solvent system in which toluene and tetrahydrofuran are mixed and a solvent system in which hexane and tetrahydrofuran are mixed can be exemplified.

The organic potassium compound used in the present invention is not limited as long as it is soluble in a polymerization solvent and has no ability to initiate polymerization of a monomer. Among them, the formula [I] R-O ^- organic potassium compounds represented by K ⁺ [I] is preferred.
In the formula [I], R represents an alkyl group, a cycloalkyl group, an alkylsulfonyl group, an arylsulfonyl group, a heteroarylsulfonyl group, an alkylcarbonyl group, an arylcarbonyl group, a heteroarylcarbonyl group, an aryl group, a heteroaryl group, an aralkyl. Group, a heteroaralkyl group, a C1-C6 alkyl group, a C3-C6 cycloalkyl group, a C1-C6 alkylsulfonyl group, an arylsulfonyl group, a heteroarylsulfonyl group, a C1-C6 alkylcarbonyl group, an arylcarbonyl group, a heteroaryl A carbonyl group, an aryl group, a heteroaryl group, an aralkyl group, and a heteroaralkyl group are preferable, and a C1-C6 alkyl group, an aryl group, a heteroaryl group, and a C1-C6 alkylcarbonyl group are more preferable. These groups may have a substituent, and examples of the substituent include a C1-C6 alkyl group and a C1-C6 alkoxy group.

As an organic potassium compound,
Potassium salts of C1-C24 linear, branched or cyclic alcohols such as methanol, ethanol, isopropanol, n-butanol, t-butanol, stearyl alcohol, cyclohexanol,

  2-allylphenol, eugenol, isoeugenol, 4-tert-amylphenol, 4-n-amyloxyphenol, 4- (1-adamantyl) phenol, 1- (2-pyridylazo) -2-naphthol, 1- (2 -Thiazolylazo) -2-naphthol, 2-benzylphenol, 4-tert-butylphenol, 4-n-butylphenol, 3-butoxyphenol, 6-tert-butyl-m-cresol, 4-hydroxy-3-tert-butylanisole 6-tert-butyl-o-cresol, 3-tert-butylphenol, 2-sec-butylphenol, 6-tert-butyl-2,4-xylenol, 2-tert-butyl-p-cresol, 4- (benzyloxy) ) Phenol, 2- (benzyloxy) ) Phenol, 4-benzylideneaminophenol, 2-tert-butyl-4-ethylphenol, 4-tert-butoxyphenol, 2,4-bis (α, α-dimethylbenzyl) phenol, 4-sec-butyl-2, 6-di-tert-butylphenol, carvacrol, 2- (3-sec-butyl-5-tert-butyl-2-hydroxyphenyl) benzotriazole, 4-phenylphenol, 4-α-cumylphenol, 4-cyclohexyl Phenol, 2-cyclohexyl-5-methylphenol, 2,6-di-tert-butyl-p-cresol, 2,4-di-tert-butylphenol, N, N-diethyl-3-aminophenol, 2,6- Diisopropylphenol, 2,6-dimethoxyphenol, 2-dimethyl Ruaminomethylphenol, 2,6-dimethylphenol, 4-tert-butyl-2,6-diisopropylphenol, 4,6-di-tert-butyl-m-cresol, 2- (3,5-di-tert- Butyl-2-hydroxyphenyl) -5-chlorobenzotriazole, 2,6-di-tert-butyl-4-ethylphenol, 2,6-di-tert-butyl-4-methoxyphenol, N, N- Dibutyl-3-aminophenol, 2,3-dihydro-2,2-dimethyl-7-hydroxybenzofuran, 2,6-di-tert-butyl-4-dimethylaminomethylphenol, 2,6-diphenylphenol, 3, Diethyl 5-di-tert-butyl-4-hydroxybenzylphosphonate, 2,4-di-tert-amylphenol, 2,6-dibromo-p-cresol, 2-ethoxy-5- (1-propenyl) phenol, 4-hydroxybenzophenone, umbelliferone, 5-hydroxyindane, 2-hydroxy-4-methoxybenzophenone, 2-hydroxy- 4-n-octyloxybenzophenone, 8-quinolinol, 4-hexyloxyphenol, 4-heptyloxyphenol, 2- (2-hydroxy-5-methylphenyl) benzotriazole, 2- (5-chloro-2-benzotria) Zolyl) -6-tert-butyl-p-cresol, 2- (3,5-di-tert-amyl-2-hydroxyphenyl) benzotriazole, 2- (5-tert-butyl-2-hydroxyphenyl) benzo Triazole, 10-hydroxybenzo [h] quinoline, 8 Hydroxyjulolidine, 2- (2-hydroxyphenyl) benzothiazole, 1- (3-hydroxybenzyl) piperidine, 4-methoxy-1-naphthol, p-naphtholbenzein, 4-n-octyloxyphenol, 8-hydroxy -7-propylquinoline, 2-propyl-4- (4-pyridylazo) phenol, 2,4,6-tri-tert-butylphenol, 2,4,6-tris (dimethylaminomethyl) phenol, 4-triphenylmethyl Potassium salts of phenols such as phenol, m-cresol indophenol, thymol indophenol, 2-phenylphenol, potassium salt of naphthol,

  Pivalic acid, isobutyric acid, hexanoic acid, 2-ethylhexanoic acid, decanoic acid, lauric acid, myristic acid, stearic acid, N-lauroylsarcosine, 1-naphthaleneacetic acid, oleic acid, linoleic acid, sorbic acid, phenoxyacetic acid, α -Methoxyphenylacetic acid, 3-phenoxypropionic acid, 4-phenoxybutyric acid, N, N-diethylglycine, 2-naphthoic acid, picolinic acid, 5-phenoxy-n-valeric acid, 3- (4-methoxyphenyl) propionic acid 3,4-methylenedioxyphenylacetic acid, (±) -2- (6-methoxy-2-naphthyl) propionic acid, 2-naphthyloxyacetic acid, 2-phenoxypropionic acid, anthraquinone-2-carboxylic acid, 4- Amyloxybenzoic acid, 2-anthracenecarboxylic acid, 4-butylbenzoic acid, 4-tert-butyl Tylbenzoic acid, 4-benzoylbenzoic acid, 4-benzyloxybenzoic acid, 4- (4-tertbutylphenyl) benzoic acid, 3,5-dibenzyloxybenzoic acid, 4-cyclohexylbenzoic acid, 4'-decyloxy Biphenyl-4-carboxylic acid, 2,3-dihydrobenzofuran-7-carboxylic acid, 4-diethylaminobenzoic acid, 3,5-di-tert-butylbenzoic acid, 4- (dodecyloxy) benzoic acid, 3 ′, 4 '-Dimethylbenzophenone-2-carboxylic acid, 4- (diphenylphosphino) benzoic acid, 9,9-dimethylfluorene-2-carboxylic acid, 4-ethoxybenzoic acid, 2-ethoxy-1-naphthoic acid, fluorescein, 9 -Fluorenone-2-carboxylic acid, 3-fluoro-4-n-octyloxybenzoic acid, 1-fluorenecarboxylic acid 4- (4-heptylphenyl) benzoic acid, 4- (4-hexylphenyl) benzoic acid, 4-hexylbenzoic acid, 4-isobutylbenzoic acid, 6-methoxy-2-naphthoic acid, 4- (methylthio) benzoic acid 4-n-octyloxybenzoic acid, 4-n-octylbenzoic acid, piperonyl acid, 2-phenoxybenzoic acid, 2-phenylthiomethylbenzoic acid, 1-pyrenecarboxylic acid, 2-propoxybenzoic acid, 6-quinoline Carboxylic acid, 3,4,5-trimethoxybenzoic acid, 2,4,6-trimethylbenzoic acid, 2- (p-tolyl) benzoic acid, 3,4,5-tris (benzyloxy) benzoic acid, 4-un Potassium salts of carboxylic acids such as decyloxybenzoic acid, potassium salt of 4-methoxycinnamic acid,

  2-mercaptobenzothiazole, 5-mercapto-3-phenyl-1,3,4-thiadiazole-2-thione, s-butyl mercaptan, t-butyl mercaptan, 2-methyl-2-butanethiol, isoamyl mercaptan, 2- Methyl-1-butanethiol, 3-methyl-2-butene-1-thiol, cyclohexanethiol, cyclopentanethiol, 1-heptanethiol, tert-octanethiol, 1-decanethiol, 1-undecanethiol, 1-dodecanethiol 1-tetradecanethiol, 1-hexadecanethiol, n-pentadecyl mercaptan, 1-octadecanethiol, tert-tetradecanethiol, 2-dimethylaminoethanethiol, 2-diethylaminoethanethiol, 2-diisopropyl Minoethanethiol, benzyl mercaptan, 4-methoxybenzyl mercaptan, 2-phenylethyl mercaptan, 2-mercaptothiazoline, 2-mercapto-5-thiazolidone, 2-mercapto-5-methylthio-1,3,4-thiadiazole, 2- Methyltetrahydrofuran-3-thiol, (2-mercaptoethyl) pyrazine, 4-pyridineethanethiol, trimethylsilylmethanethiol, 2-thiophenemethanethiol, potassium salt of 1- (4-ethoxyphenyl) -5-mercapto-1H-tetrazole Potassium salts of thioalcohols such as

  Thiophenol, 4-methylthiophenol, 4- (methylthio) benzenethiol, 4-t-butylthiophenol, 4-isopropylbenzenethiol, 5-tert-butyl-2-methylbenzenethiol, 4-methoxybenzenethiol, 4- Chlorobenzenethiol, 2,5-dimethylbenzenethiol, 2,4-dimethylbenzenethiol, 3,4-dimethylbenzenethiol, 3,4-dimethoxybenzenethiol, 3-ethoxybenzenethiol, 2-ethylbenzenethiol, 4-ethylbenzenethiol , Potassium salts of thiophenols such as 2-naphthalenethiol potassium salt,

Potassium salts of thiocarboxylic acids such as potassium isopropylxanthate, potassium ethylxanthate, potassium butylxanthate, potassium amylxanthate, potassium dibenzyldithiocarbamate, potassium thiobenzoate,
1-butanesulfonic acid, 1-hexanesulfonic acid, 1-heptanesulfonic acid, 1-octanesulfonic acid, 1-nonanesulfonic acid, 1-decanesulfonic acid, 1-undecanesulfonic acid, 1-pentadecanesulfonic acid, 1- Dodecanesulfonic acid, 1-tridecanesulfonic acid, 1-octadecanesulfonic acid, dodecylsulfuric acid, 1-hexadecanesulfonic acid, heptadecafluoro-1-octanesulfonic acid, anthraquinone-2-sulfonic acid, 9,10-dimethoxyanthracene- 2-sulfonic acid, 2,4-dimethylbenzenesulfonic acid, mesitylenesulfonic acid, 4-n-octylbenzenesulfonic acid, 2-morpholinoethanesulfonic acid, 2-morpholinopropanesulfonic acid, 3- (trimethylsilyl) -1-propane Sulfonic acid, dansylic acid, dodecy And potassium sulfonic acids salts such as potassium salt of benzenesulfonic acid,

thiosulfonic acid potassium salt such as p-toluenethiosulfonic acid potassium salt,
Phosphoric acid potassium salts such as monododecyl phosphate, diphenyl phosphate, diisopropyl phosphate, dibutyl phosphate, dioleyl phosphate, di-2-ethylhexyl phosphate, didecyl phosphate, potassium salt of dibenzyl phosphate,
Carbazole, indole, phenothiazine, phenoxazine, hexamethyldisilazane, phthalimide, 1,2,4-triazole, 6-methyl-1,2,3-oxathiazin-4 (3H) -one, 2,2-dioxide, Potassium salts of nitrogen compounds such as thiomorpholine, potassium salt of morpholine,
Other potassium salts such as tetrakis (4-chlorophenyl) boric acid and tris (3,5-dimethylpyrazol-1-yl) borohydride can be mentioned.

The amount of the potassium compound used in the present invention can be arbitrarily used within a range that does not affect the polymerization. Specifically, it is 10 mol% or more and 20 times mol or less in terms of molar ratio to the initiator. More preferably, it is 50 mol% or more and 5 times mol or less. If it is less than 10 mol%, the polymerization rate will be slow, and there may be cases where a polymer with controlled molecular weight and molecular weight distribution cannot be produced stably and with good reproducibility. May not be compatible with the polymerization solution, or the growth rate during the polymerization reaction may be significantly reduced.
The order of adding the organic potassium compound to the reaction system is not particularly limited. It may be added during the polymerization reaction of the styrene monomer, or may be added to the reaction system before the styrene monomer is added.
By adding an organic potassium compound, the polymerization reaction rate can usually be accelerated even in a solvent system having a slow polymerization reaction rate (a system containing 50 to 80% by weight or more of a nonpolar or low-polar solvent). As a result, the polymerization reaction is completed quickly, and a narrowly dispersed polymer can be obtained.

  The styrenic monomer is not particularly limited as long as it is a compound in which an anionic polymerizable unsaturated bond is bonded to an aromatic hydrocarbon, but the formula [II]

The compound represented by these is preferable. A styrene-type monomer can be used individually by 1 type or in combination of 2 or more types.
In the formula [II], R ¹ represents a hydrogen atom or an alkyl group, preferably a hydrogen atom or a C1-C6 alkyl group. R ² represents an alkyl group, an alkoxy group, a t-butoxycarbonyl group, a t-butoxycarbonylmethyl group, or a tetrahydropyranyl group, and is a C1-C6 alkyl group, a C1-6 alkoxy group, a t-butoxycarbonyl group, t -A butoxycarbonylmethyl group or a tetrahydropyranyl group is preferred. p represents an integer of 0 to 5, and when p is 2 or more, R ² may be the same or different. As p, 1-3 are preferable.
The alkyl group of R ^1, the alkyl group of R ² , and the alkoxy group may have a substituent, and examples of the substituent include a C1 to C6 alkyl group, a C1 to C6 alkoxy group, and a phenyl group. .

  Specific examples of the compound represented by the formula [II] include styrene, α-methylstyrene, α-methyl-p-methylstyrene, p-methylstyrene, m-methylstyrene, o-methylstyrene, p-ethyl. Styrene, 2,4-dimethylstyrene, 2,5-dimethylstyrene, p-isopropylstyrene, 2,4,6-triisopropylstyrene, pt-butoxystyrene, pt-butoxy-α-methylstyrene, m -T-butoxystyrene, pt-butoxycarbonylstyrene, pt-butoxycarbonylmethylstyrene, o-1-ethoxyethoxystyrene, m-1-ethoxyethoxystyrene, p-1-ethoxyethoxystyrene, etc. be able to. Styrenic monomers can be used alone or in combination of two or more.

In the present invention, the polymerization reaction is started with an anionic polymerization initiator. The anionic polymerization initiator is not particularly limited as long as it is a nucleophile and has a function of initiating polymerization of an anion polymerizable monomer. For example, an alkali metal, an organic alkali metal, or the like can be used. .
Specific examples of the alkali metal include lithium, sodium, potassium, cesium and the like.
Examples of the organic alkali metal include alkylated products, allylated products, and arylated products of the above alkali metals. Specifically, ethyl lithium, n-butyl lithium, sec-butyl lithium, t-butyl lithium, ethyl sodium, lithium biphenyl, lithium naphthalene, lithium triphenyl, sodium naphthalene, 1,1-diphenylhexyl lithium, 1,1 -Diphenyl-3-methylpentyl lithium, 1,4-dilithio-2-butene, 1,6-dilithiohexane, polystyryl lithium and the like can be used. These anionic polymerization initiators can be used alone or in combination of two or more.

The usage-amount of an anionic polymerization initiator is 0.001-0.2 equivalent normally with respect to the anionic polymerizable monomer to be used, Preferably it is 0.005-0.1 equivalent. By using an anionic polymerization initiator in this range, the target polymer can be produced with high yield.
The usage-amount of a polymerization initiator is 0.0001-0.2 equivalent normally with respect to the styrene-type monomer to be used, Preferably it is 0.0005-0.1 equivalent. By using a polymerization initiator in this range, the target polymer can be produced with good yield.
The polymerization temperature in the present invention is not particularly limited as long as no side reaction such as transfer reaction or termination reaction occurs, and the monomer is consumed and the polymerization is completed, but the temperature range is from -100 ° C to -30 ° C. Is preferably carried out. More preferably, it is carried out in a temperature range of −60 ° C. to −30 ° C.

The concentration of the monomer with respect to the polymerization solvent is not particularly limited, but is usually in the range of 1 to 40% by weight, and particularly preferably in the range of 5 to 25% by weight.
As for the molecular weight of the polymer produced in the present invention, the number average molecular weight by GPC measurement is preferably 30000 or more.
In the present invention, even in a mixed solvent system consisting of 50 to 95% by weight of a nonpolar or low polarity solvent and 50 to 5% by weight of a polar solvent, the polymerization rate is controlled at a temperature of −100 to −30 ° C., A styrenic polymer having a high molecular weight (molecular weight of 30000 or more) and narrow dispersibility (molecular weight distribution: 1.01-1.30) can be produced.
[Example]
EXAMPLES Hereinafter, although this invention is demonstrated in detail using an Example, the technical scope of this invention is not limited to these illustrations.

  Under a nitrogen atmosphere, a mixed solvent of tetrahydrofuran (100 g) and toluene (200 g) was cooled to −40 ° C., and an n-butyllithium solution (1.86 g, 4 mmol) was added. Thereafter, pt-butoxystyrene (64.07 g, 364 mmol) was added to tetrahydrofuran (30 g), and a solution dehydrated with dibutyl magnesium hexane solution (0.97 g, 1 mmol) was added dropwise over 8 minutes. Subsequently, potassium pivalate (0.14 g, 1 mmol) was added to tetrahydrofuran (20 g), and a solution dehydrated with dibutylmagnesium hexane solution (0.34 g, 0.5 mmol) was added. After stirring for 30 minutes, methanol (1. 70 g) was added and killed. When this solution was measured by GPC, a polymer having a molecular weight (Mn) of 68000 and a dispersity of 1.15 was produced. Further, when this solution was measured by gas chromatography, no monomer remained.

  Under a nitrogen atmosphere, a mixed solvent of tetrahydrofuran (200 g) and toluene (400 g) was cooled to −40 ° C., and an n-butyllithium solution (1.96 g, 5 mmol) was added. Thereafter, pt-butoxystyrene (127.13 g, 721 mmol) was added to tetrahydrofuran (50 g), and a solution dehydrated with dibutylmagnesium hexane solution (1.15 g, 2 mmol) was added dropwise over 20 minutes. Subsequently, 12% t-butoxypotassium / THF solution (1.75 g, 2 mmol) was added, and after stirring for 30 minutes, methanol (1.53 g) was added and killed. When this solution was measured by GPC, a polymer having a molecular weight (Mn) of 47000 and a dispersity of 1.07 was produced. Further, when this solution was measured by gas chromatography, no monomer remained.

  Under a nitrogen atmosphere, a mixed solvent of tetrahydrofuran (200 g) and toluene (400 g) was cooled to −40 ° C., and an n-butyllithium solution (1.75 g, 4 mmol) was added. Diphenylethylene (0.57 g, 3 mmol) was added, stirred for 15 minutes, and 12% t-butoxypotassium / THF solution (0.97 g, 1 mmol) was added. Next, pt-butoxystyrene (126.98 g, 720 mmol) was added to tetrahydrofuran (50 g), and a solution dehydrated with dibutyl magnesium hexane solution (1.25 g, 2 mmol) was added dropwise over 20 minutes, followed by stirring for 30 minutes. Thereafter, methanol (1.95 g) was added and killed. When this solution was measured by GPC, a polymer having a molecular weight (Mn) of 121000 and a dispersity of 1.25 was produced. Further, when this solution was measured by gas chromatography, no monomer remained.

  Under a nitrogen atmosphere, a mixed solvent of tetrahydrofuran (30 g) and toluene (270 g) was cooled to −40 ° C., and an n-butyllithium solution (1.61 g, 4 mmol) was added. Thereafter, pt-butoxystyrene (63.73 g, 362 mmol) was added to tetrahydrofuran (30 g), and a solution dehydrated with dibutylmagnesium hexane solution (0.99 g, 1 mmol) was added dropwise over 20 minutes. Subsequently, 12% t-butoxy potassium / THF solution (0.50 g, 0.5 mmol) was added, and after stirring for 30 minutes, methanol (1.99 g) was added and killed. When this solution was measured by GPC, a polymer having a molecular weight of 71000 and a dispersity of 1.05 was produced. Further, when this solution was measured by gas chromatography, no monomer remained.

Under a nitrogen atmosphere, a mixed solvent of tetrahydrofuran (200 g) and toluene (400 g) was cooled to −40 ° C., and n-butyllithium solution (1.66 g, 4 mmol) and 12% t-butoxypotassium / THF solution (0.86 g). 1 mmol) was added. Then, pt-butoxystyrene (52.71 g, 299 mmol) and styrene (31.35 g, 301 mmol) were added to tetrahydrofuran (40 g), and the solution dehydrated with dibutylmagnesium hexane solution (0.63 g, 1 mmol) was added for 20 minutes. Over a period of 15 minutes. When this solution was measured by GPC, a polymer having a molecular weight (Mn) of 67000 and a dispersity of 1.11 was produced. Further, when this solution was measured by gas chromatography, no monomer remained.
Subsequently, diphenylethylene (0.55 g, 3 mmol) was added to a 3.71% lithium chloride / tetrahydrofuran solution (3.23 g, 3 mmol), and a solution dehydrated with a diethylzinc hexane solution (0.35 g, 0.5 mmol) was added. The mixture was stirred for 15 minutes and cooled to -50 ° C. Next, methyl methacrylate (16.24 g, 162 mmol) was added to tetrahydrofuran (15 g), and a solution dehydrated with diethylzinc hexane solution (0.50 g, 1 mmol) was added dropwise over 7 minutes. After completion of the addition, the mixture was stirred for 40 minutes. Then, methanol (1.97 g) was added and killed. When this solution was measured by GPC, a polymer having a molecular weight (Mn) of 74000 and a dispersity of 1.14 was produced. Further, when this solution was measured by gas chromatography, no monomer remained.

[Comparative Example 1]
When the reaction was carried out under the same conditions as in Example 1 except that potassium pivalate was not added, the monomer remained in the solution after killing.

Claims (5)

Anionic polymerization of styrenic monomer at a temperature of -100 to -30 ° C in the presence of an organic potassium compound in a mixed solvent composed of 50 to 95% by weight of a nonpolar or low polarity solvent and 50 to 5% by weight of a polar solvent A method for producing a styrenic polymer having a number average molecular weight of 30,000 or more and a molecular weight distribution (Mw / Mn) of 1.01 to 1.30. The organic potassium compound has the formula [I]
R-O ^- K ⁺ [I]
Wherein R is an alkyl group, a cycloalkyl group, an alkylsulfonyl group, an arylsulfonyl group, a heteroarylsulfonyl group, an alkylcarbonyl group, an arylcarbonyl group, a heteroarylcarbonyl group, an aryl group, a heteroaryl group, an aralkyl group or The method for producing a styrenic polymer according to claim 1, wherein the compound is represented by the following formula: Styrene monomer is represented by the formula [II]

(In the formula, R ¹ represents a hydrogen atom or an alkyl group, and R ² represents an alkyl group, an alkoxy group, a t-butoxycarbonyl group, a t-butoxycarbonylmethyl group, or a tetrahydropyranyl group. P is 2. In the above case, they may be the same or different, and p represents an integer of 0 to 5.) The production of the styrenic polymer according to claim 1 or 2, Method. The method for producing a styrene polymer according to any one of claims 1 to 3, wherein the nonpolar or low polarity solvent is an aromatic hydrocarbon solvent. The method for producing a styrene polymer according to any one of claims 1 to 4, wherein the polar solvent is an ether solvent.