JP5362185B2 - Method for producing polymer by living anionic polymerization method using polymerization stabilizer - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for the production of a polymer by living anionic polymerization capable of producing a polymer having stably controlled molecular weight and narrow molecular weight distribution independent of the combination of the kind of polymerization initiator, solvent and monomer, polymerization temperature, etc. <P>SOLUTION: The method for the production of a polymer by living anionic polymerization is carried out by adding an alkali metal salt of a thiol such as a thiol lithium salt to the system. <P>COPYRIGHT: (C)2008,JPO&amp;INPIT

Description

  The present invention relates to a method for producing a polymer by a living anion polymerization method, and more particularly to a method for producing a polymer by a living anion polymerization method using a polymerization stabilizer (polymerization control agent).

  In living anionic polymerization such as styrene and methyl methacrylate (MMA) using an organic alkali metal compound such as alkyl lithium as a polymerization initiator, the molecular weight is generally controlled because the initiation reaction is faster than the growth reaction. A polymer having a narrow distribution can be produced. However, depending on the combination of the polymerization initiator, the type of the solvent and the monomer, the polymerization temperature, and the like, the rates of the initiation reaction and the growth reaction may be approximated or reversed.

  In the polymerization of methacrylic acid esters such as methyl methacrylate, lithium chloride, lithium salt of ethylene glycol monomethyl ether, etc. function as a polymerization control agent, which can produce a polymer with a controlled molecular weight and a narrow molecular weight distribution. (For example, refer to Patent Document 1).

  However, these polymerization control agents are difficult to use in polymerization using a solvent with low polarity such as toluene. In addition, these polymerization control agents have little effect on monomers having an aromatic unsaturated bond such as styrene or an aliphatic unsaturated bond such as butadiene.

Japanese Patent Laid-Open No. 2003-082010

  An object of the present invention is to provide a living anion that can stably produce a polymer having a narrow molecular weight distribution with stable molecular weight control, without being affected by the combination of polymerization initiator, solvent and monomer types, polymerization temperature, etc. It is providing the manufacturing method of the polymer by a polymerization method.

  As a result of diligent research to solve the above problems, the present inventors have found that an alkali metal salt of thiol becomes an additive for controlling living anionic polymerization stably without being affected by the polymerization environment. The present invention has been completed.

  That is, the present invention includes (1) a method for producing a polymer characterized in that living anion polymerization is performed by adding an alkali metal salt of thiol into the system, and (2) an alkali metal salt of thiol is aromatic. (3) The method for producing a polymer according to (1) above, wherein the alkali metal salt of thiol is an alkali metal salt of a nitrogen-containing aromatic thiol. ).

  The present invention also provides (4) the method for producing a polymer according to any one of (1) to (3) above, wherein the alkali metal salt of thiol is a lithium salt of thiol, The method for producing a polymer according to any one of the above (1) to (4), wherein an alkali metal salt of thiol is used in an amount of 0.5 equivalent or more with respect to the polymerization initiator, or (6) an organic The present invention relates to the method for producing a polymer as described in any one of (1) to (5) above, wherein a metal compound or an art complex thereof is added to the system.

  Furthermore, the present invention provides the method for producing a polymer as described in (6) above, wherein (7) the organometallic compound is dialkylmagnesium, dialkylzinc or trialkylaluminum, and (8) a styrene-based heavy polymer. A polymer production method according to any one of (1) to (7) above, wherein (9) a nonpolar solvent or a low polarity solvent is polar, It relates to the manufacturing method of the polymer in any one of said (1)-(8) characterized by using together with a solvent.

  According to the method for producing a polymer of the present invention, a polymer having a narrow molecular weight distribution and a stable molecular weight can be produced without being affected by a combination of a polymerization initiator, a solvent and a monomer, and a polymerization temperature. can do.

  The method for producing the polymer of the present invention is not particularly limited as long as it is a method for adding living cation polymerization by adding an alkali metal salt of thiol into the system, and according to the production method of the present invention, The polymerization can be controlled and living anion polymerization can be performed stably without being affected by the polymerization environment such as the polymerization initiator, the kind of the solvent and the monomer, and the polymerization temperature. The production method of the present invention can be used in the production of copolymers such as homopolymers, random copolymers, block copolymers, etc., and is also useful in the production of block copolymers in which polymerization is relatively difficult to control. is there. In addition, the polymer obtained by the production method of the present invention is useful as a resist agent because it is controlled with high accuracy so as to have a desired molecular weight and a narrow molecular weight distribution. The polymer obtained by the production method of the present invention has a molecular weight dispersity (weight average molecular weight (Mw) / number average molecular weight (Mn)) of usually about 1.01-1.50, preferably Is 1.01-1.20, more preferably 1.01-1.15.

  The alkali metal salt of thiol used in the production method of the present invention is not particularly limited as long as it is soluble in a polymerization solvent. Examples of the alkali metal in the alkali metal salt of thiol include lithium, sodium, and potassium. Lithium is preferred. Examples of the thiols in the alkali metal salt of thiol include aliphatic thiols and aromatic thiols, aromatic thiols are preferred, and nitrogen-containing aromatic thiols are more preferred.

  Specifically, C1-C18 alkyl thiol such as ethane thiol, propane thiol, benzyl mercaptan, 2-mercaptoethyl ether and cyclohexyl thiol, cycloalkyl thiol, thiol containing a hydroxyl group such as mercaptoethanol and p-mercaptophenol, Thiols containing carboxylic acid esters such as methyl mercaptoacetate and ethyl mercaptopropionate, aromatic thiols such as benzenethiol, toluenethiol and naphthalenethiol, 2-mercapto-1-methylimidazole, mercaptopyridine, mercaptothiazoline, mercaptobenzthiazoline And nitrogen-containing aromatic thiols such as mercaptobenzoxazole and mercaptopyrimidine. Two or more alkali metal salts of thiol can be used in combination.

  The amount of alkali metal salt of thiol used in the production method of the present invention is not particularly limited and can be controlled more reliably and accurately, so that the polymerization reaction can be performed. It is preferably 0.5 equivalent or more, and more preferably 1.0 equivalent or more. In addition, the upper limit is not particularly limited, but purification becomes difficult when the amount of alkali metal salt of thiol in the obtained polymer increases, or the physical properties of the polymer increase when the residual amount of alkali metal salt of thiol increases. Is less than 20 equivalents, more preferably less than 10 equivalents, and even more preferably less than 5 equivalents. Addition of the alkali metal salt of thiol can be performed before or after the addition of the polymerization initiator, and may be added during the polymerization.

Further, in the production method of the present invention, it has a function of stabilizing the growth anion terminal and allowing the polymerization to proceed smoothly and reacting with an active hydrogen compound or the like existing in the system to inhibit the polymerization reaction. It is preferable to add an organometallic compound and / or an art complex thereof because it can be prevented. As the organometallic compound, specifically, a compound represented by the formula (I) can be preferably exemplified.

Formula (I): (R ¹ ) _m M

In the formula (I), R ¹ 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 ¹ 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 (I) include di-n-butylmagnesium, di-t-
Organic magnesium compounds such as butyl magnesium, di-s-butyl magnesium, n-butyl-s-butyl magnesium, n-butyl-ethyl magnesium, di-n-amyl magnesium, dibenzyl magnesium, diphenyl magnesium; diethyl zinc, dibutyl zinc Organic zinc compounds such as trimethylaluminum, triethylaluminum, triisobutylaluminum and tri-n-hexylaluminum; and the like, and dialkylmagnesium, dialkylzinc or trialkylaluminum are preferred. These can be used alone or in combination of two or more.

  The amount of the organometallic compound used can be arbitrarily used within a range that does not affect the polymerization. For example, it is preferably used in a range of 0.1 to 20 times by mole with respect to the polymerization initiator. A polymer whose molecular weight and molecular weight distribution are controlled at a growth rate can be more stably produced with good reproducibility.

  The anionically polymerizable monomer used in the production method of the present invention is not particularly limited as long as it has an anionically polymerizable unsaturated bond, and specifically includes a styrene monomer, (meth) acrylic acid. An ester monomer or a conjugated diene monomer can be preferably exemplified. In the production method of the present invention, even in the polymerization of a styrene monomer or a conjugated diene monomer, which has conventionally been difficult to control polymerization, with high accuracy. Polymerization can be controlled.

  Specific examples of the styrene monomer include styrene, α-alkyl styrene, and nucleus-substituted styrene (styrene having a substituent on an aromatic ring). 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, and specifically includes an alkyl group, an alkoxyalkyl group, an alkoxy group. , 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. Among these, styrene, styrene having an aromatic ring substituted with an alkyl group, styrene having an aromatic ring substituted with an alkoxy group, α-alkyl styrene, α-alkyl styrene having an aromatic ring substituted with an alkyl group, or an alkoxy group with an aromatic ring Α-alkylstyrene substituted by is preferred.

  Examples of the conjugated diene monomer include a butadiene monomer, and more specifically 1,3-butadiene, isoprene, 2,3-dimethylbutadiene, 2-ethyl-1,3-butadiene, 1 , 3-pentadiene and the like can be exemplified, and these can be used alone or in combination of two or more.

  In addition, as the (meth) acrylic acid ester monomer, one having an ester alcohol residue having 1 to 20 carbon atoms is preferable from the viewpoint of reactivity, and specifically, methyl ester, ethyl ester, isopropyl ester, n- A butyl ester etc. can be illustrated and the thing whose ester alcohol residue is tertiary carbon is preferable. These can be used alone or in combination of two or more.

  The anionic polymerization initiator used in the present invention 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, alkali metal, organic alkali Metal compounds and the like can be used.

  Examples of the alkali metal include lithium, sodium, potassium, cesium and the like. Examples of the organic alkali metal compound include alkylated products, allylated products, and arylated products of the above alkali metals, and alkyllithium is particularly preferable. 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 1,1-diphenylhexyl lithium, 1,1-diphenyl-3-methylpentyl lithium, 1,4-dilithio-2-butene, 1,6-dilithiohexane, polystyryl lithium, cumyl potassium, cumyl cesium 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 0.0001-0.2 equivalent normally with respect to the whole anionic polymerizable monomer to be used, Preferably it is 0.0005-0.1 equivalent. By using an anionic polymerization initiator in this range, the target polymer can be produced with high yield.

  The polymerization temperature in the present invention is not particularly limited as long as the side reaction such as transfer reaction or termination reaction does not occur and the monomer is consumed and the polymerization is completed, but the temperature range is from −100 ° C. to the solvent boiling point. Is preferably carried out. The concentration of the monomer with respect to the polymerization solvent is not particularly limited, but is usually 1 to 40% by weight, preferably 2 to 15% by weight.

  The polymerization solvent used in the production method of the present invention is not particularly limited as long as it does not participate in the polymerization reaction and is compatible with the polymer, and specifically includes diethyl ether, tetrahydrofuran (THF), dioxane. , Polar compounds such as ether compounds such as trioxane, tertiary amines such as tetramethylethylenediamine and hexamethylphosphoric triamide, and non-aliphatic, aromatic or alicyclic hydrocarbon compounds such as hexane and toluene A polar solvent or a low polarity solvent can be illustrated. These solvents can be used alone or as a mixed solvent of two or more. In the production method of the present invention, polymerization can be accurately controlled even when a nonpolar solvent or a low polarity solvent is used in combination with a polar solvent. For example, the nonpolar solvent or the low polarity solvent is based on the whole solvent. 5 vol% or more can be used, 20 vol% or more may be used, and 50 vol% or more may be used.

  In the present invention, an additive such as an alkali metal salt or an alkaline earth metal salt can be added at the start of polymerization or during polymerization as required. Specific examples of such additives include mineral salts and halides such as sodium, potassium, barium and magnesium sulfates, nitrates and borates. More specifically, lithium And barium chloride, bromide, iodide, lithium borate, magnesium nitrate, sodium chloride, potassium chloride and the like. Among these, lithium halides such as lithium chloride, lithium bromide, lithium iodide, and lithium fluoride are preferable, and lithium chloride is particularly preferable.

  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. By using a multistage polymerization in which a monomer is added to adjust the molecular weight, the molecular weight can be regulated more precisely.

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

  In a nitrogen atmosphere, 0.51 g (2.8 mmol) of diphenylethylene and 1.07 g (9.7 mmol) of thiophenol were added to 100 g of tetrahydrofuran (THF), and then 4.88 g of an n-BuLi solution at −50 ° C. 11.7 mmol) was added and stirred for 25 minutes. Thereafter, a solution obtained by adding 5.51 g (55.0 mmol) of methyl methacrylate and 0.23 g (0.3 mmol) of diethylzinc hexane to 10 g of THF was added dropwise over 3 minutes. Added killing. 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 7100 and a dispersion degree of 1.07 was produced.

  Under a nitrogen atmosphere, 0.48 g (4.0 mmol) of 2-mercaptothiazoline and 0.45 g (2.0 mmol) of p-methylphenylcinnamyl ether were dissolved in 120 g of THF, and 2.64 g of an n-BuLi solution at −40 ° C. (6.4 mmol) was added, stirred for 30 minutes, and then cooled to -50 ° C. Next, 1.10 g (1.5 mmol) of diethyl zinc hexane solution was added and stirred for 3 minutes. Thereafter, a solution prepared by dissolving 5.84 g (58.3 mmol) of methyl methacrylate and 0.32 g (0.4 mmol) of diethylzinc solution in 6 g of THF was added dropwise over 5 minutes. Added killing. 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 9000 and a dispersity of 1.06 was produced.

  Under a nitrogen atmosphere, 0.17 g (1.5 mmol) of thiophenol was dissolved in 160 g of THF, 0.89 g (2.1 mmol) of n-BuLi solution was added to the solvent at −50 ° C., and the mixture was stirred for 30 minutes. Subsequently, 0.39 g (0.5 mmol) of diethyl zinc solution was added and stirred for 5 minutes. Thereafter, 6.99 g (49.2 mmol) of t-butyl methacrylate was added, and 1.03 g (4.4 mmol) of 2,4-diphenyl-4-methyl-1-pentene was dissolved in 10 g of THF as an initiator, and n-BuLi. 2.51 g (6.0 mmol) of solution was added, 0.52 g (0.2 mmol) of the solution stirred at room temperature for 70 minutes was added, stirred for 70 minutes, and methanol was added to kill. 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 54400 and a dispersion degree of 1.08 was produced.

  In 150 g of THF, 0.12 g (1.0 mmol) of 2-mercaptothiazoline was added, 0.98 g (2.4 mmol) of n-BuLi solution was added at room temperature, and the mixture was stirred for 70 minutes. Then, it cooled to -50 degreeC, 5.42 g (52.0 mmol) of styrene was added, and 0.09 g (0.2 mmol) of n-BuLi solution was added subsequently, it stirred for 30 minutes, methanol was added and killed. 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 37700 and a dispersion degree of 1.06 was produced.

  Under a nitrogen atmosphere, 0.12 g (1.0 mmol) of p-mercaptophenol was dissolved in 160 g of THF, and 1.44 g (3.5 mmol) of an n-BuLi solution was added to the solvent at room temperature, followed by stirring for 70 minutes. Subsequently, the mixture was cooled to −50 ° C., and 5.56 g (53.4 mmol) of styrene was added. Thereafter, 1.19 g (5.0 mmol) of 2,4-diphenyl-4-methyl-1-pentene was dissolved in 12 g of THF as an initiator, and 2.84 g (6.8 mmol) of an n-BuLi solution was added. 0.62 g (0.2 mmol) of the stirred solution was added, stirred for 10 minutes, and methanol was added to kill. 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 65900 and a dispersion degree of 1.08 was produced.

Under a nitrogen atmosphere, 2.12 g (5.08 mmol) of an n-BuLi solution was added to a solution of 160 g of toluene and 0.56 g (5.08 mmol) of thiophenol dissolved in 40 g of THF at room temperature, and the mixture was stirred for 60 minutes. Subsequently, the mixture was cooled to −40 ° C., 23.2 g (222.8 mmol) of styrene was added, then 1.26 g (3.02 mmol) of n-BuLi solution was added, and the mixture was stirred for 30 minutes. When the polymerization solution was sampled and measured by gas chromatography, no monomer remained. Further, when GPC measurement was performed, a polymer having a molecular weight (Mw) of 9100 and a dispersion degree of 1.03 was produced.
To this polymerization solution, 1.27 g (7.05 mmol) of 1,1-diphenylethylene was added and stirred for 10 minutes, and then 4.97 g (49.6 mmol) of methyl methacrylate added with 0.4 g (0.54 mmol) of diethylzinc solution. ) Was added dropwise over 5 minutes. After completion of dropping, the mixture was 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 11300 and a dispersity of 1.04 was produced.

Under a nitrogen atmosphere, 1.80 g (4.32 mmol) of an n-BuLi solution was added to a solution obtained by dissolving 0.46 g (3.96 mmol) of cyclohexanethiol in 160 g of toluene and 40 g of THF, and the mixture was stirred for 60 minutes. Subsequently, the mixture was cooled to −40 ° C., 23.1 g (221.8 mmol) of styrene was added, then 1.23 g (2.95 mmol) of n-BuLi solution was added, and the mixture was stirred for 30 minutes. When the polymerization solution was sampled and measured by gas chromatography, no monomer remained. Further, when GPC measurement was performed, a polymer having a molecular weight (Mw) of 8000 and a dispersity of 1.04 was produced.
To this polymerization solution, 1.51-g (8.64 mmol) of 1,1-diphenylethylene was added and stirred for 10 minutes, and then, 5.72 g (57.1 mmol) of methyl methacrylate added with 0.4 g (0.54 mmol) of diethylzinc solution. ) Was added dropwise over 5 minutes. After completion of dropping, the mixture was 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 9600 and a dispersion degree of 1.06 was produced.

[Comparative Example 1]
After adding 0.47 g (2.6 mmol) of diphenylethylene and 0.97 (9.0 mmol) of p-cresol in 100 g of THF under a nitrogen atmosphere, 5.13 g (12.3 mmol) of an n-BuLi solution at −50 ° C. ) And stirred for 25 minutes. Thereafter, a solution obtained by adding 5.60 g (55.9 mmol) of methyl methacrylate and 0.29 g (0.4 mmol) of a diethylzinc hexane solution to 10 g of THF was dropped over 3 minutes. Added killing. 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 4000 and a dispersity of 1.20 was produced.

Claims (8)

A method for producing a polymer, wherein a living anion polymerization is carried out by adding an alkali metal salt of thiol into the system. The method for producing a polymer according to claim 1, wherein the alkali metal salt of thiol is an alkali metal salt of aromatic thiol. The method for producing a polymer according to claim 2, wherein the alkali metal salt of thiol is an alkali metal salt of a nitrogen-containing aromatic thiol. The method for producing a polymer according to any one of claims 1 to 3, wherein the alkali metal salt of thiol is a lithium salt of thiol. The method for producing a polymer according to any one of claims 1 to 4, wherein an alkali metal salt of thiol is used in an amount of 0.5 equivalent or more based on the polymerization initiator. The method for producing a polymer according to any one of claims 1 to 5, wherein an organometallic compound or an art complex thereof is added to the system. The method for producing a polymer according to claim 6, wherein the organometallic compound is dialkylmagnesium, dialkylzinc or trialkylaluminum. The method for producing a polymer according to any one of claims 1 to 7, wherein a styrene polymer or a conjugated diene polymer is produced.