JP5189746B2 - Method for producing styrenic polymer - Google Patents

Description

  The present invention relates to a method for producing a styrenic polymer by an anionic polymerization method and a polymer obtained by such a method, and easily polymerizes a styrenic monomer at high speed using an ether group-containing solvent even near room temperature. And a polymer obtained by such a method.

  In general, in the anionic polymerization of a styrene monomer using an organic alkali metal compound such as alkyl lithium as an initiator, when the polymerization is performed near room temperature using an ether group-containing solvent such as tetrahydrofuran, the initiator reacts with the solvent. The reaction was carried out at a temperature of about −80 ° C. (for example, see Patent Document 1), or polymerization was carried out using a hydrocarbon solvent such as toluene. However, anionic polymerization of a styrene monomer using a hydrocarbon polymerization solvent has a problem that the polymerization reaction is remarkably slow.

Further, in the anionic polymerization of a styrene monomer using an organic alkali metal compound as an initiator, when an ether group-containing solvent is used as a solvent, the styrene monomer is relatively compared with the initiation reaction of the initiator and the styrene monomer. It is known that polymerization control becomes difficult because the polymerization rate increases. Therefore, when such an ether group-containing solvent is used, in order to increase the reaction rate (initiation reaction rate) of the initiator, for example, s − having a high reaction initiation rate is used instead of n-butyllithium having a low initiation reaction rate. Butyl lithium, t-butyl lithium and the like are used. However, s-butyllithium, t-butyllithium, and the like have a drawback that handling properties and the like are significantly inferior to those of n-butyllithium. In addition, alkali metals such as metallic lithium, metallic sodium, metallic potassium and the like also have a disadvantage that handling properties are extremely inferior.

  Furthermore, in the anionic polymerization of styrene-based monomers, for example, the molecular weight is about 3000 or less, and the molecular weight distribution (ratio of weight average molecular weight (Mw) to number average molecular weight (Mn) (Mw / Mn)) is 1.2 or less. It was extremely difficult to produce a polymer having a low molecular weight and narrow dispersibility.

JP 2004-323588 A

  The object of the present invention is to suppress a side reaction at the polymerization initiation stage by using a polymerization initiator excellent in handling properties even in a high temperature near room temperature in anionic polymerization using a polymerization solvent containing an ether group-containing solvent. An object of the present invention is to provide a method capable of producing a styrene polymer exhibiting narrow dispersibility even with a low molecular weight by controlling the polymerization, and a polymer produced by such a method.

  As a result of intensive studies to solve the above problems, the present inventors use such a solvent even when a polymerization solvent containing an ether group-containing solvent is used by using an organometallic compound in combination with a specific polymerization initiator. The inventors have found that it is possible to produce a styrenic polymer exhibiting narrow dispersibility even with a low molecular weight by suppressing various adverse effects caused by this, and have completed the present invention.

That is, the present invention relates to (1) a polymerization initiator represented by the formula (I) in a solvent containing an ether group-containing solvent (wherein R ₁ is a hydrogen atom, an alkyl optionally having a substituent). A phenyl group which may have a substituent or a substituent, R ₂ represents an alkyl group which may have a substituent, and R ₃ represents an alkyl group which may have a substituent. Or an alkoxy group that may have a substituent, and when n is 2 or more, they may be the same or different, n represents an integer of 0 to 5. X represents an alkali metal. ) And an organometallic compound, and a method for producing a styrene polymer, wherein a styrene monomer is polymerized at a temperature of −10 ° C. or higher and a boiling point of a solvent or lower,

(2) The present invention relates to the method for producing a styrenic polymer as described in (1) above, wherein X is a lithium atom.

The present invention also includes (3) an organic alkali metal compound and a compound represented by the formula (II) in an ether group-containing solvent (wherein R ₄ is a hydrogen atom or an alkyl group optionally having a substituent). , Or a phenyl group which may have a substituent, R ₅ represents a hydrogen atom or an alkyl group, and R ₆ represents a hydrogen atom, an alkyl group which may have a substituent, or a substituent. Represents an optionally substituted phenyl group, R ₇ represents an optionally substituted alkyl group, or an optionally substituted alkoxy group, and n ′ represents 0 to 5 (Representing an integer) is reacted to form a polymerization initiator represented by the formula (I), and then an organometallic compound is added thereto. Manufacturing method of coalescence,

(4) The method according to (3) above, wherein the organic alkali metal compound is alkyl lithium.

Further, in the present invention, (5) the organometallic compound has the formula (III): (R ₈ ) _m M (wherein R ₈ represents a C1-C20 alkyl group or a C6-C20 aryl group, and m is 2 or more. In this case, R ₈ may be the same or different, M represents an atom belonging to Group 2, 12 or 13 of the long-period periodic table, and m represents the valence of M. Or a styrene polymer production method according to any one of (1) to (4) above, wherein (6) the organometallic compound is dialkylzinc, dialkylmagnesium or The method for producing a styrenic polymer as described in (5) above, which is a trialkylaluminum, or (7) The above method, wherein an alkali metal salt of thiol is added to an ether group-containing solvent (1) to (6) A method for producing a ren polymer, (8) the method for producing a styrene polymer according to any one of the above (1) to (7), wherein the ether group-containing solvent is tetrahydrofuran, 9) The present invention relates to a styrenic polymer produced by the production method according to any one of (1) to (8) above.

  According to the method for producing a styrenic polymer of the present invention, even when a polymerization solvent containing an ether group-containing solvent is used, at a high temperature around room temperature, a polymerization initiator having excellent handling properties is used. By controlling the polymerization while suppressing the side reaction, for example, a styrene polymer exhibiting narrow dispersibility having a molecular weight distribution of 1.2 or less can be produced even with a low molecular weight of 3000 or less. Since the polymer obtained by the production method of the present invention is well controlled in molecular weight and molecular weight distribution, it is useful as a material such as a resist material and various polymer additives.

  As a method for producing the styrenic polymer of the present invention, a polymerization initiator represented by formula (I) and an organometallic compound are added to a solvent containing an ether group-containing solvent, and the boiling point of the solvent is −10 ° C. or higher. The method is not particularly limited as long as it is a method for polymerizing a styrene monomer at the following temperature, and the order of addition of the polymerization initiator represented by the formula (I) and the organometallic compound is not particularly limited. In addition, it is preferable to add a styrenic monomer after the addition of the polymerization initiator represented by the formula (I) and the organometallic compound.

  In the production method of the present invention, the reaction with the ether group-containing solvent can be suppressed by using a specific polymerization initiator, and the polymerization rate (growth rate) of the styrene monomer can be obtained by using an organometallic compound. ) Can be suppressed (or the initiation reaction rate of the initiator and the styrenic monomer can be increased), for example, 5 to 5 without causing the polymerization system to have a low temperature (for example, about −80 ° C.). Even at a room temperature of about 40 ° C., polymerization can be controlled while suppressing side reactions, and a styrene polymer exhibiting narrow dispersibility can be produced even at a low molecular weight.

In formula (I), R ₁ represents a hydrogen atom, an alkyl group which may have a substituent, or a phenyl group which may have a substituent. Examples of the alkyl group include a C1-C12 alkyl group, and a C1-C6 alkyl group is preferable. Specifically, a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, An s-butyl group, a t-butyl group, an isobutyl group, etc. can be mentioned. Examples of the substituent when R ₁ is an alkyl group include an alkoxy group such as a methoxy group and an ethoxy group, and a phenyl group. Examples of the substituent when R ₁ is a phenyl group include alkyl groups such as a methyl group and an ethyl group, and alkoxy groups such as a methoxy group and an ethoxy group.

R ₂ represents an alkyl group which may have a substituent, and examples thereof include a C1 to C24 alkyl group, preferably a C1 to C12 alkyl group, specifically, a methyl group, an ethyl group, Group, n-propyl group, isopropyl group, n-butyl group, s-butyl group, t-butyl group, isobutyl group and the like. Examples of the substituent when R ₂ is an alkyl group include an alkoxy group such as a methoxy group and an ethoxy group, and a phenyl group.

R ₃ represents an alkyl group which may have a substituent, or an alkoxy group which may have a substituent, n represents an integer of 0 to 5, and when n is 2 or more, R ₃ May be the same or different. n is preferably 1 to 3. Examples of the alkyl group include a C1 to C12 alkyl group, and a C1 to C6 alkyl group is preferable. Specific examples include a methyl group, an ethyl group, an n-propyl group, an isopropyl group, and an n-butyl group. Group, s-butyl group, t-butyl group, isobutyl group and the like. Examples of the alkoxy group include a C1-C12 alkoxy group, and a C1-C6 alkoxy group is preferable. Specifically, a methoxy group, an ethoxy group, an n-propoxy group, an isopropoxy group, an n- A butoxy group, a s-butoxy group, a t-butoxy group, an isobutoxy group, and the like can be given. . Examples of the substituent when R ₃ is an alkyl group include alkoxy groups such as a methoxy group and an ethoxy group.

  X represents an alkali metal, preferably a lithium atom, a sodium atom, or a potassium atom, and particularly preferably a lithium atom.

Examples of the polymerization initiator represented by the above formula (I) include organic alkali metal compounds and formula (II).
It can obtain by making the compound represented by these react. Examples of the organic alkali metal compound include alkylated products, allylated products, and arylated products of alkali metals such as lithium, sodium, and potassium, with lithium alkylated products being preferred. Specifically, ethyl lithium, n-butyl lithium, sec-butyl lithium, t-butyl lithium, ethyl sodium, lithium biphenyl, lithium naphthalene, lithium triphenyl, sodium naphthalene, potassium naphthalene, α-methylstyrene sodium dianion, 1 , 1-diphenylhexyllithium, 1,1-diphenyl-3-methylpentyllithium, 1,4-dilithio-2-butene, 1,6-dilithiohexane, polystyryllithium, cumylpotassium, cumylcesium, etc. . Among these, n-butyl lithium, sec-butyl lithium, and t-butyl lithium are preferable. In the present invention, the polymerization can be carried out while controlling the polymerization even if n-alkyllithium such as n-butyllithium which is easy to handle is used. These organic alkali metal compounds can be used alone or in combination of two or more.

In formula (II), R ₆ , R ₇ and n ′ have the same meanings as R ₁ , R ₃ and n in formula (I), respectively.

R ₄ represents a hydrogen atom, an optionally substituted alkyl group, or an optionally substituted phenyl group. Examples of the alkyl group include C1-C12 alkyl groups, and C1 -C6 alkyl group is preferable, and specific examples include methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, s-butyl group, t-butyl group, and isobutyl group. . Examples of the substituent when R ₄ is an alkyl group include alkoxy groups such as a methoxy group and an ethoxy group. Examples of the substituent when R ₄ is a phenyl group include alkyl groups such as a methyl group and an ethyl group, and alkoxy groups such as a methoxy group and an ethoxy group.

R ₅ represents a hydrogen atom or an alkyl group, and examples of the alkyl group include a C1-C18 alkyl group, preferably a C1-C12 alkyl group, specifically, a methyl group, an ethyl group, n- Examples include propyl group, isopropyl group, n-butyl group, s-butyl group, t-butyl group, isobutyl group and the like.

  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.

Further, the organometallic compound used in the present invention is particularly limited as long as it is a compound capable of suppressing the polymerization rate of the styrene monomer (or increasing the initiation reaction rate of the initiator and the styrene monomer). Specifically, there can be mentioned a compound represented by the formula (III).

Formula (III): (R ₈ ) _m M

In the formula (III), R ₈ represents a C1-C20 alkyl group or a C6-C20 aryl group. Examples of the C1-C20 alkyl group include methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, s-butyl group, t-butyl group, isobutyl group, amyl group, hexyl group, and benzyl group. Can be mentioned. Moreover, as a C6-C20 aryl group, a phenyl group, a naphthyl group, etc. are mentioned.

m represents the valence of M, and when m is 2 or more, R ₈ may be the same or different. M represents an atom belonging to Group 2 of the long periodic table such as magnesium or calcium; an atom belonging to Group 12 such as zinc or cadmium; or an atom belonging to Group 13 such as aluminum.

  Specific examples of the compound represented by the formula (III) include di-n-butyl magnesium, di-t-butyl magnesium, di-s-butyl magnesium, n-butyl-s-butyl magnesium, and n-butyl-ethyl. Organic magnesium compounds such as magnesium, di-n-amylmagnesium, dibenzylmagnesium and diphenylmagnesium; Organic zinc compounds such as diethylzinc and dibutylzinc; Organics such as trimethylaluminum, triethylaluminum, triisobutylaluminum and trin-hexylaluminum An aluminum compound; etc. are mentioned, Dialkyl zinc, dialkyl magnesium, and a trialkyl aluminum are preferable. These can be used alone or in combination of two or more.

  The amount of the organometallic compound of the present invention is not particularly limited, but for example, it is preferably used in the range of 0.1 to 20 times mol and in the range of 1/2 to 5 times mol relative to the polymerization initiator. More preferably it is used. As a result, a polymer having a controlled molecular weight and molecular weight distribution can be more stably produced with good reproducibility.

  In addition, the styrene monomer used in the present invention is not particularly limited as long as it has an anionically polymerizable unsaturated bond. Specifically, styrene, α-alkylstyrene, nucleus-substituted styrene, and the like are used. It can be illustrated. The nuclear substituent is not particularly limited as long as it is an anionic species having a polymerization initiating ability and an inactive group with respect to an anionic species having no polymerization initiating ability. , Alkoxyalkoxy groups, t-butoxycarbonyl groups, t-butoxycarbonylmethyl groups, tetrahydropyranyl groups, and the like. Further, specific examples of the styrene derivative include α-methylstyrene, α-methyl-p-methylstyrene, p-methylstyrene, m-methylstyrene, o-methylstyrene, p-ethylstyrene, 2,4-dimethylstyrene. 2,5-dimethylstyrene, p-isopropylstyrene, 2,4,6-triisopropylstyrene, pt-butoxystyrene, pt-butoxy-α-methylstyrene, mt-butoxystyrene, etc. can do. These can be used alone or in combination of two or more.

  Examples of the ether group-containing solvent in the solvent containing the ether group-containing solvent of the present invention include ether compounds such as diethyl ether, tetrahydrofuran (THF), dioxane, and trioxane. Moreover, these solvents can be used individually by 1 type or in mixture of 2 or more types. The solvent that can be used in combination with the ether group-containing solvent is not particularly limited as long as it is a polar solvent that does not participate in the polymerization reaction and is compatible with the polymer. For example, tetramethylethylenediamine, hexamethylphosphoric triamide And tertiary amines such as Furthermore, even if it is an aliphatic, aromatic or alicyclic hydrocarbon compound having a low polarity, it can be used in combination with an ether group-containing solvent as long as it is relatively compatible with the polymer. And a combination of hexane and THF. 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 2 to 15% by weight.

  Examples of the solvent containing an ether group-containing solvent in the present invention include those containing 1 wt% or more, 10 wt% or more, 30 wt% or more, 50 wt% or more, or 80 to 100 wt% of an ether group containing solvent. In the present invention, even when an ether group-containing solvent is used, the polymerization is controlled while suppressing side reactions at a high temperature around room temperature, and a styrene system exhibiting narrow dispersibility even at a low molecular weight. A polymer can be produced.

  In the present invention, an alkali metal salt of thiol may be added to the ether group-containing solvent. By using an alkali metal salt of thiol in combination, polymerization control becomes easy and a polymer having a narrow molecular weight distribution can be synthesized. The thiols in the alkali metal salt of thiol can be used regardless of the type of aliphatic or aromatic, but aromatic thiols are preferred, and nitrogen-containing aromatic thiols are more preferred. Specifically, C1-C18 alkyl thiols such as ethanethiol, propanethiol and cyclohexyl thiol, thiols containing hydroxyl groups such as mercaptoethanol and p-mercaprophenol, methyl mercaptoacetate and ethyl mercaptopropionate. Thiols containing carboxylic acid esters such as benzene, aromatic thiols such as toluene thiol and naphthalene thiol, and nitrogen-containing aromatic thiols such as mercaptothiazoline, mercaptobenzthiazoline and mercaptopyrimidine. Moreover, examples of the alkali metal in the alkali metal salt of thiol include lithium, sodium, and potassium, and lithium is particularly preferable. These thiol alkali metal salts can be used singly or in combination of two or more.

  The amount of alkali metal salt of thiol used is not particularly limited, but it is preferably used in the range of 0.1 to 20 times mol, and used in the range of 1/2 to 10 times mol with respect to the polymerization initiator. Is more preferable. As a result, a polymer having a controlled molecular weight and molecular weight distribution can be more stably produced with good reproducibility.

  In the present invention, an alkali metal salt or an alkaline earth metal salt may be added, whereby the living anion can be stabilized and polymerization can be performed more stably.

  Specific examples of the alkali metal salt and alkaline earth metal salt include mineral salts and halides such as sodium, potassium, barium, magnesium sulfate, nitrate, borate, and the like. Specifically, lithium and barium chlorides, bromides, iodides, lithium borate, magnesium nitrate, sodium chloride, potassium chloride and the like can be mentioned. Among these, lithium halides such as lithium chloride, odor Lithium iodide, lithium iodide or lithium fluoride is preferred, and lithium chloride is particularly preferred. These can be used alone or in combination of two or more.

  The amount of alkali metal salt and alkaline earth metal salt used can be arbitrarily used within a range that does not affect the polymerization, and can be used, for example, 1/10 to 100 times mol of the polymerization initiator, It is preferable to use in 2-20 times mole. By using it at 1/2 to 20 times mol, a polymer with controlled molecular weight and molecular weight distribution can be produced more stably and with good reproducibility.

  The polymer obtained by the production method of the present invention is a monodispersed polymer with a narrow molecular weight distribution. For example, even if the molecular weight is 5000 or less and 3000 or less, the molecular weight dispersity is 1.01-1. Polymers of .50, preferably 1.01-1.20 can be produced.

  In the present invention, in order to more accurately define the molecular weight of the obtained polymer, after polymerizing a certain monomer, the molecular weight is grasped by GPC or the like, and further required for the desired molecular weight of the polymer. The molecular weight can be regulated more precisely by using multi-stage polymerization in which the monomer is added and the molecular weight is adjusted.

  EXAMPLES Hereinafter, although an Example demonstrates this invention more concretely, the technical scope of this invention is not limited to these illustrations.

  Under nitrogen atmosphere, 1.29 g (7.2 mmol) of 1,1-diphenylethylene was added to 100 g of THF, and 1.32 g (3.2 mmol) of n-BuLi solution was added at room temperature (about 25 ° C.), followed by stirring for 15 minutes. did. Subsequently, 2.15 g (3.0 mmol) of diethylzinc hexane solution was added and stirred for 25 minutes. Thereafter, 5.1 g (48.6 mmol) of styrene was added, stirred for 30 minutes, and methanol was added to kill it. When this killing solution was measured by gas chromatography, no monomer remained. Further, when GPC measurement was performed, a polymer having a molecular weight (Mw) of 2590 and a dispersity of 1.06 was produced.

  Under nitrogen atmosphere, 0.51 g (2.9 mmol) of 1,1-diphenylethylene was added to 50 g of THF, 1.55 g (3.7 mmol) of n-BuLi solution was added at room temperature (about 25 ° C.), and the mixture was stirred for 5 minutes. did. Subsequently, 2.18 g (3.0 mmol) of diethylzinc hexane solution was added and stirred for 10 minutes. Thereafter, 5.7 g (32.4 mmol) of pt-butoxystyrene was added, stirred for 90 minutes, and methanol was added to kill it. When this killing solution was measured by gas chromatography, no monomer remained. Further, when GPC measurement was performed, a polymer having a molecular weight (Mw) of 2550 and a dispersity of 1.07 was produced.

  Under a nitrogen atmosphere, 0.14 g (0.8 mmol) of 1,1-diphenylethylene was added to 50 g of THF, 0.77 g (1.9 mmol) of an n-BuLi solution was added at room temperature (about 25 ° C.), and the mixture was stirred for 10 minutes. did. Subsequently, 0.78 g (1.1 mmol) of dibutylmagnesium solution was added and stirred for 10 minutes. Thereafter, 5.0 g (28.6 mmol) of pt-butoxystyrene was added, stirred for 150 minutes, and methanol was added to kill it. When this killing solution was measured by gas chromatography, no monomer remained. Further, when GPC measurement was performed, a polymer having a molecular weight (Mw) of 17200 and a dispersity of 1.30 was produced.

  Under a nitrogen atmosphere, 0.38 g (2.1 mmol) of 2,4-diphenyl-4-methyl-1-pentene was dissolved in a mixed solvent of 120 g of THF and 80 g of toluene, and the n-BuLi solution was dissolved at room temperature (about 25 ° C.). 1.07 g (2.6 mmol) was added and stirred for 20 minutes. Next, 1.60 g (2.3 mmol) of dibutylmagnesium solution was added and stirred for 4 minutes. Then, it cooled to 0 degreeC, what added 0.33 g (0.5 mmol) of dibutyl magnesium solutions to 18.00 g (102.1 mmol) of pt-butoxystyrene was dripped over 6 minutes, and after completion | finish of dripping, The mixture was stirred for 60 minutes, and methanol was added to kill it. When this killing solution was measured by gas chromatography, no monomer remained. Further, when GPC measurement was performed, a polymer having a molecular weight (Mw) of 48200 and a dispersity of 1.27 was produced.

Claims (6)

A polymerization initiator represented by formula (I) and a dialkylzinc are added to a solvent containing an ether group-containing solvent, and a styrene monomer is polymerized at a temperature of -10 ° C or higher and a boiling point of the solvent or lower. A method for producing a styrene polymer.

(In the formula, R ₁ represents a hydrogen atom, an alkyl group which may have a substituent, or a phenyl group which may have a substituent, and R ₂ may have a substituent. R ₃ represents an alkyl group which may have a substituent, or an alkoxy group which may have a substituent, and when n is 2 or more, they are the same or different. (N represents an integer of 0 to 5. X represents an alkali metal.)   The method for producing a styrenic polymer according to claim 1, wherein X is a lithium atom. In the ether group-containing solvent, an organoalkali metal compound and a compound represented by formula (II) are reacted to form a polymerization initiator represented by formula (I), and then an organometallic compound is added. The method for producing a styrenic polymer according to claim 1 or 2.

(In the formula, R ₄ represents a hydrogen atom, an optionally substituted alkyl group, or an optionally substituted phenyl group, R ₅ represents a hydrogen atom, an alkyl group, and R _6. Represents a hydrogen atom, an optionally substituted alkyl group, or an optionally substituted phenyl group, and R ₇ represents an optionally substituted alkyl group or substituted. Represents an alkoxy group which may have a group, and n ′ represents an integer of 0 to 5.)   The method for producing a styrenic polymer according to claim 3, wherein the organic alkali metal compound is alkyl lithium.   The method for producing a styrenic polymer according to any one of claims 1 to 4, wherein an alkali metal salt of thiol is added to the ether group-containing solvent.   The method for producing a styrenic polymer according to any one of claims 1 to 5, wherein the ether group-containing solvent is tetrahydrofuran.