JP5550519B2 - Method for producing anionic polymer - Google Patents

Description

  The present invention relates to a method for producing a polymer by an anionic polymerization method, and more specifically, a high molecular weight polymer can be easily produced without strict purification of raw materials, and precise molecular weight control of the obtained polymer is performed. The present invention relates to a method for producing an anionic polymer.

  In anionic polymerization systems, active hydrogen compounds such as water and alcohol, and oxygen become polymerization inhibitors that deactivate the growth terminal anions and initiators, so controlling anionic polymerization in the presence of these is difficult. It has been known.

  On the other hand, for example, when producing a polymer having a high molecular weight of tens of thousands or more by an anionic polymerization method, the more the high molecular weight polymer is obtained, the lower the concentration of the growth terminal anion in the polymerization solution. In particular, the influence of the polymerization inhibitor increases, and the growth terminal anion tends to be deactivated. For this reason, it is difficult to obtain a polymer having a desired molecular weight, and the yield of the target polymer is often reduced.

  In order to solve such problems, benzylmagnesium bromide, butyllithium or the like is added to the monomer or solvent to be used and reacted with an active hydrogen-containing polymerization inhibitor contained in a trace amount in the monomer or solvent. A method for removing a polymerization inhibitor from a body or solvent and purifying it has been proposed.

  In this method, it is necessary to add an excessive amount of benzylmagnesium bromide, butyllithium or the like in order to completely remove the polymerization inhibitor. However, since these reagents may function as a polymerization inhibitor or a polymerization initiator, they must be completely removed from the monomer or solvent before polymerization. Therefore, the purification operation becomes complicated, and when the monomer is purified by a distillation method or the like, the monomer partially polymerizes, and the purification and recovery rate of the monomer may decrease. There was a problem in practical use when anionic polymerization was carried out on a production scale.

  In addition, Hsieh et al. Conducted anionic polymerization of styrene and dienes using an ate complex of sec-butyllithium or a polystyryl anion and dibutylmagnesium at room temperature, and Sawamoto et al. Used to report bulk polymerization of styrene at a polymerization temperature of 120 ° C. However, even in these examples using dibutyl magnesium, the molecular weight of the high molecular weight polymer has not been precisely controlled (see Non-Patent Documents 1 to 4).

H. L. Hsieh et. al. , Macromolecules, 1986, 19, 299. Seltz, L.M. Little, G .; F. , J .; Organomet. Chem. , 1969, 18, 227 A. Diffieux, et. al. , Macromol. Chem. Phys. 1999, 200, 621 7th SPSJ International Polymer conference, 27A13 (1999)

  The present invention has been made in view of the above-described prior art, and has a high molecular weight even when a polymerization inhibitor is present in the system or when a polymerization inhibitor is introduced from the outside. It is an object of the present invention to provide a method for producing an anionic polymer capable of producing the above polymer and capable of precisely controlling the molecular weight of the obtained anionic polymer.

  As a result of intensive studies to solve the above problems, the present inventors have found that an anion species having a polymerization initiating ability and an anion species having no polymerization initiating ability but capable of reacting with a polymerization inhibitor include an anion species. It has been found that by adding a polymerizable monomer, a high molecular weight polymer can be produced, and precise molecular weight control of the resulting anionic polymer becomes possible, and the present invention has been completed.

Thus, according to the present invention, the following anionic polymer production methods (1) to (5) are provided.
(1) An organic anion species having a polymerization initiating ability , an organic anion species of an art complex having a carbon anion derived from 1,1-diphenylethylene or stilbene as one organometallic compound , and a polymerization initiating ability Organic anion species that can be converted into a compound that does not inhibit polymerization by reacting with a polymerization inhibitor but is composed of an organic alkali metal and an organic metal containing magnesium, aluminum, or zinc as a metal species A method for producing an anionic polymer, comprising adding an anionic polymerizable monomer to a polymerization reaction initiation system in which seeds are present and polymerizing in a temperature range of -100 ° C or higher and + 20 ° C or lower.

(2) An anion-polymerizable monomer is added to the polymerization reaction initiation system in which an art complex of 1,1-diphenylhexyllithium and dibutylmagnesium and an art complex of n-butyllithium and dibutylmagnesium are present; A method for producing an anionic polymer, wherein polymerization is performed in a temperature range of 100 ° C. or higher and + 20 ° C. or lower.
(3) An organic anion species that is not capable of initiating polymerization but can be converted into a compound that reacts with a polymerization inhibitor and does not inhibit polymerization, and an organic alkali metal and an organic metal having magnesium, aluminum, or zinc as the metal species The organic anion species present in the art complex comprising an organic anion species having a polymerization initiating ability, wherein a carbon anion derived from 1,1-diphenylethylene or stilbene is one organometallic compound. It is 0.5 mol or more with respect to 1 mol of organic anion seed | species, The manufacturing method of the anion polymer as described in (1) characterized by the above-mentioned.

(4) The method for producing an anionic polymer as described in any one of (1) to (3) , wherein the polymerization inhibitor is an active hydrogen compound.
(5) Any one of (1) to (4) , wherein the anionic polymerizable monomer is at least one selected from the group consisting of a styrene derivative, a butadiene derivative, and a (meth) acrylic ester derivative. A process for producing an anionic polymer as described in 1.

  By using the production method of the present invention, a high molecular weight polymer can be produced by controlling the molecular weight even when an anion polymerizable monomer or solvent containing a trace amount of a polymerization inhibitor is used. That is, even when an anionic polymer is produced on an industrial production scale, even if a small amount of a polymerization inhibitor is contained in the anionic polymerizable monomer or solvent used, the intended anionic polymer with a controlled molecular weight is used. Can be produced with good yield.

  The anionic polymer obtained by the production method of the present invention, particularly a high molecular weight block anionic copolymer, has a highly controlled microstructure and is useful as a nanopattern forming material.

The GPC curve figure of the polymer A obtained in Example 1 is shown.

Hereinafter, the present invention will be described in detail.
The method for producing an anionic polymer of the present invention comprises an anion species having a polymerization initiating ability and a polymerization reaction initiating system in which an anion species that does not have the ability to initiate polymerization but reacts with a polymerization inhibitor and can be converted into a compound that does not inhibit the polymerization. Further, an anionic polymerizable monomer is added.

  The anion species capable of initiating polymerization used in the present invention is not particularly limited as long as it is an anion species capable of polymerizing an anionic polymerizable unsaturated bond.

  Examples of the anion species capable of initiating polymerization include, for example, an organic alkali metal, an organic alkaline earth metal, a carbon anion derived from 1,1-diphenylethylene or stilbene; or a derivative derived from 1,1-diphenylethylene or stilbene. And an organic anion of an art complex having a carbon anion as one organometallic compound.

  Specific examples of the carbon anion include ethyl lithium, n-butyl lithium, sec-butyl lithium, t-butyl lithium, ethyl sodium, lithium biphenyl, lithium naphthalene, sodium naphthalene, potassium naphthalene, α-methylstyrene naphthalene dianion, 1 , 1-diphenylhexyl lithium, 1,1-diphenyl-3-methylpentyl lithium, 1,4-dilithio-2-butene, 1,6-dilithiohexane, polystyryl lithium, cumyl potassium, cumyl cesium, 1,1-diphenyl And carbon anions derived from ethylene or stilbene.

  Specific examples of the art complex of anionic species capable of initiating polymerization include an art complex in which a carbon anion derived from 1,1-diphenylethylene or stilbene is one organometallic compound, more specifically, Examples thereof include an art complex of 1,1-diphenylhexyllithium and dibutylmagnesium produced by the reaction of 1-diphenylethylene and n-butyllithium.

The other organometallic compound forming the art complex is not particularly limited as long as it can form an art complex with the anion species capable of initiating polymerization. Specifically, an organic metal having magnesium, aluminum, or zinc as a metal species can be exemplified.
The anionic species capable of initiating polymerization exemplified above can be used singly or in combination of two or more.

  An anionic species that can be converted into a compound that does not inhibit polymerization but does not inhibit polymerization by using a polymerization inhibitor used in the present invention (hereinafter sometimes referred to as “anionic species without polymerization initiation ability”) is anionic polymerizable. Although there is no ability to polymerize an unsaturated bond, it is not particularly limited as long as it is an anionic species that can be converted into a compound that does not inhibit polymerization by reacting with a polymerization inhibitor represented by an active hydrogen compound.

  Examples of the anion species having no ability to initiate polymerization include, for example, triphenylmethyl anion derivatives; enolate anions; metal alkoxide anions; organic metal organic anions using magnesium, aluminum, or zinc as metal species; organic alkali metals, magnesium, aluminum Or the organic anion of the art complex which consists of the organic metal which makes zinc a metal seed | species is mentioned.

  A triphenylmethyl anion derivative can be prepared, for example, by reacting a triphenylmethane derivative with alkyllithium.

  The enolate anion should be prepared by reacting a (meth) acrylic acid ester having an ester functional group with relatively little steric hindrance such as a methyl group, an ethyl group or an n-propyl group with an anionic species such as alkyllithium. Can do.

  Metal alkoxides can be prepared by reacting alcohols with alkyl lithium. Specifically, lithium methoxyethoxide produced | generated by reaction of methoxyethanol and n-butyllithium can be illustrated.

  As an organic metal having magnesium, aluminum, or zinc as a metal species, for example, a magnesium, aluminum, or zinc compound having a C 1-20 alkyl group or a C 6-20 aryl group as a ligand is used. It can be illustrated.

  Examples of the alkyl group having 1 to 20 carbon atoms and the aryl group having 6 to 20 carbon atoms include methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, sec-butyl group, t-butyl group, Examples thereof include an isobutyl group, an amyl group, a hexyl group, a benzyl group, a phenyl group, and a naphthyl group.

  Specific examples of the organic metal having magnesium, aluminum, or zinc as a metal species include di-n-butylmagnesium, di-t-butylmagnesium, di-sec-butylmagnesium, n-butyl-sec-butylmagnesium, n-butyl-ethylmagnesium, di-n-amylmagnesium, dibenzylmagnesium, diphenylmagnesium, diethylzinc, di-n-butylzinc, trimethylaluminum, triethylaluminum, triisobutylaluminum, tri-n-hexylaluminum, etc. Can be mentioned.

  Examples of the organic alkali metal that forms an art complex of an anionic species having no polymerization initiating ability include the same organic alkali metals exemplified as the anionic species having the ability to initiate polymerization.

Moreover, as an organic metal which uses magnesium, aluminum, or zinc which forms an art complex as a metal seed | species, the thing similar to the compound illustrated previously can be illustrated.
The anionic species having no ability to initiate polymerization exemplified above can be used singly or in combination of two or more.

  The production method of the present invention is characterized in that a system in which an anionic species capable of initiating polymerization and an anionic species not capable of initiating polymerization coexist is used as a polymerization reaction initiating system, and an anionic polymerizable monomer is added to the initiating system. To do.

  Anion species having no ability to initiate polymerization can be converted into a compound that does not inhibit polymerization by reacting rapidly with a polymerization inhibitor present in the reaction system, so that a relatively low concentration of polymerization terminal anion is not deactivated. The polymerization reaction can be carried out stably, and itself does not participate in the polymerization reaction. Therefore, since the molecular weight is determined only by the anion species capable of initiating polymerization, the structure of the resulting polymer can be highly controlled.

  In the polymerization reaction initiation system, the ratio of the amount of anion species having the ability to initiate polymerization and the amount of anion species having no ability to initiate polymerization can be arbitrarily set, but in order to perform the polymerization reaction more effectively, polymerization is performed. It is preferable that the anionic species having no initiating ability is equimolar or excessive in molar ratio as compared with the anionic species having the ability to initiate polymerization.

  Depending on the amount of the polymerization inhibitor present in the reaction system or the amount of the polymerization inhibitor, the amount of anionic species having no ability to initiate polymerization is considerably less than the amount of anionic species having the ability to initiate polymerization. There is a possibility that the function as a polymerization inhibitor removal agent for anionic species having no ability to initiate polymerization may not be sufficiently exhibited.

  Further, the ratio of the abundance of anion species having no polymerization initiation ability and anion species having a polymerization initiation ability should be increased as the molecular weight of the polymer to be produced increases, and the molecular weight is as high as 2 to 30,000 or more. In the case of producing a molecule, it is preferably 1 or more (that is, anionic species having no polymerization initiating ability are made larger than anionic species having a polymerization initiating ability).

  Specifically, although the amount of anionic species having no polymerization initiating ability varies depending on the monomers used, the amount of anionic species having no ability of initiating polymerization is preferably 0.5 mol or more, more preferably 0.8 mol, relative to 1 mol of anionic species having the ability to initiate polymerization. 5 to 20 mol, particularly preferably 1 to 10 mol.

  When the amount of anionic species having no polymerization initiating ability is less than 0.5 mol per 1 mol of anionic species having the ability to initiate polymerization, a high molecular weight polymer with a controlled molecular weight is stably reproducible. There is a risk that it cannot be manufactured well. On the other hand, if the amount exceeds 20 mol, the growth rate may be significantly reduced in the polymerization reaction.

  A method for preparing a polymerization reaction initiation system in which an anionic species having a polymerization initiating ability and an anionic species having no polymerization initiating ability coexist is not particularly limited, but a reaction system such as moisture adhering to a reaction vessel, moisture contained in a reaction solvent, etc. In order to eliminate the influence of the polymerization-inhibiting substance existing in the polymer and to make an anionic species having no polymerization initiating ability as described above into an excessive polymerization reaction initiating system, the polymerization is carried out in the system in which the anionic species having the initiating ability exists. A method of preparing a polymerization reaction initiation system by adding an anionic species having no initiation ability is preferred.

  In addition, anionic species having the ability to initiate polymerization and / or anionic species having no ability to initiate polymerization can be separately prepared and mixed outside the system, but have less polymerization influence and have the ability to initiate polymerization. In order to quantitatively generate anionic species, it is preferable to prepare a polymerization reaction initiation system by generating these anionic species in the system.

  Here, generating these anionic species in the system means, for example, a case where 1,1-diphenylhexyllithium is generated by adding 1,1-diphenylethylene to n-butyllithium. It is to add dibutyl magnesium to n-butyl lithium to form an art complex. In particular, it is a compound that does not have the ability to initiate polymerization or does not react with a polymerization inhibitor, and reacts with an anionic species such as an organic metal to produce a compound that has the ability to initiate polymerization or reacts with a polymerization inhibitor. In some cases, it is preferable to add a compound or the like in which the anion species such as an organic metal is not capable of initiating polymerization in consideration of the influence of a polymerization inhibitor existing in the system.

  When both an anionic species having a polymerization initiating ability and an anionic species having no initiating ability are generated in the system, the generation order is not particularly limited, but an anionic species having a polymerization initiating ability is quantitatively generated to initiate polymerization. Since an anionic species having no ability is used in excess of an anionic species having an ability to initiate polymerization, it is preferable that an anionic species having an ability to initiate polymerization is generated first, and an anionic species having no ability to initiate polymerization is generated later.

As described above, the method for preparing the polymerization initiator system is not particularly limited, but specific examples include several methods shown below.
(1) A method of adding an anionic species having no polymerization initiating ability to a system in which an anionic species having a polymerization initiating ability exists,
(2) A method of adding a compound that reacts with an anionic species having a polymerization initiating ability to generate an anionic species having no initiating polymerization ability in a system in which an anionic species having a polymerization initiating ability exists,
(3) Addition of a compound that reacts with the anion species to produce an anion species capable of initiating polymerization in a system in which an anionic species such as an organic metal does not matter whether or not its own polymerization initiation ability exists. A method of adding an anionic species not capable of initiating polymerization after generating an anionic species capable of initiating polymerization,
(4) In the system in which anion species (A1) such as an organic metal does not matter whether or not its own polymerization initiation ability is present, it reacts with the anion species (A1) to produce an anion species capable of polymerization initiation. A method of adding a compound to produce an anionic species (A3) by reacting with the anionic species (A1) after generating the anionic species (A2) by adding a compound;
(5) In the system in which anion species (A1) such as an organic metal does not matter whether or not its own polymerization initiation ability is present, it reacts with the anion species (A1) to produce an anion species capable of polymerization initiation. After the compound is added to generate the anionic species (A2), it reacts with the anionic species (A1) and (A2) to react with (A1) to produce an anionic species (A3) having no polymerization initiation ability, Examples thereof include a method of adding a compound that reacts with (A2) to generate an anionic species (A22) having a polymerization initiating ability.

  In particular, in the preparation methods (4) and (5), since the polymerization inhibitor in the reaction system can be captured by the anionic species (A3) having no polymerization initiation ability, the polymerization is initiated by reacting with the anionic species (A1). Since the amount of the anion species capable of initiating polymerization ((A2) or (A22)) can be precisely controlled by the amount of the compound that generates the capable anion species, synthesis of a high molecular weight polymer and control of the molecular weight are possible. Can be easily performed.

  As a specific example of the preparation method (4) or (5), 1,1-diphenylethylene is added to n-butyllithium to produce 1,1-diphenylhexyllithium, and dibutylmagnesium is further added. Examples thereof include a method of forming an art complex of 1,1-diphenylhexyllithium and dibutylmagnesium capable of initiating polymerization, an art complex of n-butyllithium and dibutylmagnesium not having the ability of initiating polymerization, and the like.

  The anion polymerizable monomer used in the present invention is not particularly limited as long as it has an anion polymerizable unsaturated bond. Specifically, a styrene derivative, a butadiene derivative, a (meth) acrylic acid ester derivative, etc. It can be illustrated preferably.

  Specific examples of the styrene derivative include styrene, α-alkylstyrene, and styrene having a nuclear substituent.

  The nuclear substituent is not particularly limited as long as it is an inactive group with respect to an anionic species having a polymerization initiating ability and an anionic species having no ability to initiate polymerization. Specific examples include an alkyl group, an alkoxyalkyl group, an alkoxy group, an alkoxyalkoxy group, a t-butoxycarbonyl group, a t-butoxycarbonylmethyl group, a tetrahydropyranyl group, and the like.

  Specific examples of α-alkyl styrene and styrene having a nuclear substituent include hs, α-methyl styrene, α-methyl-p-methyl styrene, p-methyl styrene, m-methyl styrene, o-methyl styrene, p-ethyl styrene. 2,4-dimethylstyrene, 2,5-dimethylstyrene, p-isopropylstyrene, 2,4,6-triisopropylstyrene, pt-butoxystyrene, pt-butoxy-α-methylstyrene, m- Examples include t-butoxystyrene.

  Examples of the butadiene derivative include 1,3-butadiene, isoprene, 2,3-dimethylbutadiene, 2-ethyl-1,3-butadiene, 1,3-pentadiene, and the like.

  The (meth) acrylic acid ester derivative is preferably an ester alcohol residue having 1 to 20 carbon atoms from the viewpoint of reactivity. Examples of such (meth) acrylic acid ester derivatives include methyl ester, ethyl ester, isopropyl ester, n-butyl ester and the like.

  These monomers can be used alone or in combination of two or more. The production method of the present invention can also be applied to the production of copolymers such as block copolymers and random copolymers.

  The polymerization temperature of the anionic polymerizable monomer is not particularly limited as long as it does not cause side reactions such as transfer reaction and termination reaction, and the monomer is consumed and the polymerization is completed, but it is −100 ° C. or higher and + 20 ° C. It is preferable to carry out in the following temperature range.

The polymerization reaction of the anionic polymerizable monomer can be performed in a suitable polymerization solvent.
The polymerization solvent to be used 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.

  Specific examples include ether compounds such as diethyl ether, tetrahydrofuran (THF), dioxane and trioxane; tertiary amines such as tetraethylenediamine and hexamethylphosphoric triamide; and the like. These solvents can be used alone or as a mixed solvent of two or more.

  Among these, ether compounds having low polarity are preferable, and THF is particularly preferable. Moreover, even if it is an aliphatic, aromatic, or alicyclic hydrocarbon compound with low polarity, if it is comparatively compatible with a polymer, it can be used by combining with a polar solvent. Specifically, a combination of hexane and THF can be exemplified.

  The amount of the solvent used is not particularly limited, but is an amount such that the concentration of the anionic polymerizable monomer with respect to the polymerization solvent is usually in the range of 1 to 40% by weight, preferably in the range of 2 to 5% by weight. .

In the present invention, if necessary, an additive can be added at the start of polymerization or during polymerization.
Additives used include alkali metal mineral salts such as sulfates, nitrates and borates such as sodium and potassium; alkaline earth metal mineral acids such as sulfates, nitrates and borates such as barium and magnesium Examples thereof include salts; halides of alkali metals such as sodium and potassium; halides of alkaline earth metals such as barium and magnesium;

  More specifically, lithium, barium chloride, bromide, iodide, lithium borate, magnesium nitrate, sodium chloride, potassium chloride and the like can be mentioned. Among these, it is preferable to use lithium halides such as lithium chloride, lithium bromide, lithium iodide or lithium fluoride, particularly lithium chloride.

  In addition, in order to more accurately define the molecular weight of the polymer obtained, after polymerization of a certain monomer, the molecular weight is measured by gel permeation chromatography (GPC), the progress of the polymerization reaction The molecular weight can be more precisely defined by using multistage polymerization in which the molecular weight is adjusted by adding a monomer required for the molecular weight of the desired polymer.

The production method of the present invention makes it possible to remove substances that inhibit anionic polymerization, such as active hydrogen-containing compounds such as water, in the polymerization system.
Accordingly, (a) it is possible to carry out anionic polymerization even if a compound such as distillation, which is difficult to purify, is used as a monomer, and (b) deactivation of anionic species capable of initiating polymerization is suppressed. It becomes easy to define the molecular weight of the coalescence. Further, (c) even in the production of several hundreds of thousands or more high molecular weight products, which are usually difficult to carry out anionic polymerization, the deactivation of the growing terminal anion is suppressed, so that anionic polymerization can be carried out efficiently.

  In addition, when an organic metal having magnesium, aluminum, or zinc as a metal species is used, (d) the organic metal is stabilized by coordination with the growth terminal anion, and anionic polymerization can be performed with good control. e) When an art complex of an anionic species derived from 1,1-diphenylethylene or stilbene and an organic metal such as dibutylmagnesium is used as an anionic species capable of initiating polymerization, the amount of the anionic species may be specified. Since it becomes easy, a polymer whose molecular weight is precisely controlled can be obtained.

  Among the polymers obtained from the production method of the present invention, a multi-block copolymer produced from a combination of different monomers is used as a polymer for a self-organized nanopatterning material that requires precise microphase separation. Preferably used.

  In particular, a single amount in which a non-polar monomer such as styrene, vinyl naphthalene or butadiene and a polar monomer such as an acetal protecting monomer of pt-butoxystyrene, t-butyl methacrylate and 2-hydroxyethyl methacrylate are protected. And a multi-block copolymer with a monomer having a functional group such as glycidyl methacrylate is preferred.

  EXAMPLES Hereinafter, although an Example and a comparative example demonstrate this invention further in detail, the scope of the present invention is not limited to a following example.

Example 1
Under a nitrogen atmosphere, a flask containing 567 g of THF was cooled to −40 ° C., and 5.55 g (13.3 mmol) of an n-BuLi solution was added thereto. In this solution, 0.08 g (0.44 mmol) of diphenylethylene (DPE) was added and stirred at −40 ° C. for 15 minutes, and then 9.74 g (13.7 mmol) of dibutyl magnesium solution (Bu ₂ Mg) was added. did.

Next, 31.8 g (305.3 mmol) of styrene was added to the reaction solution, and the mixture was stirred at −40 ° C. for 1 hour. Methanol was added to the resulting reaction mixture to stop the reaction, followed by reprecipitation with a methanol solvent, filtration, and air-drying of the obtained filtrate to obtain a polymer A (yield). Rate 99%).
The Mw of the polymer A was 81,600.

The gel permeation chromatography (GPC) curve of the resulting polymer A is shown in FIG.
In FIG. 1, the horizontal axis represents the retention time (minutes) and the vertical axis represents the absorption intensity (retention capacity).
From FIG. 1, it was found that in Example 1 to which DPE and Bu ₂ Mg were added, a polymer having a molecular weight defined only by the amount of styrene and the amount of DPE was obtained (efficiency 97%).

(Comparative example)
Under a nitrogen atmosphere, a flask containing 568 g of THF was cooled to −40 ° C., and 0.5 g (1.2 mmol) of an n-BuLi solution was added thereto. To this solution, 0.24 g (1.32 mmol) of diphenylethylene (DPE) was added and stirred at −40 ° C. for 15 minutes, and then 30.3 g (290.9 mmol) of styrene was added to the reaction solution and stirred. However, the pale orange anion color was completely erased in about 1 minute.
The styrene monomer was hardly consumed and remained in a large amount, and the obtained polymer was a very small amount.

Claims (1)

A styrene derivative is added to the polymerization reaction initiation system in which an art complex of 1,1-diphenylhexyllithium and dibutylmagnesium, and an art complex of n-butyllithium and dibutylmagnesium exists, and the temperature is from −100 ° C. to + 20 ° C. A method for producing an anionic polymer, which comprises polymerizing in a temperature range.

Images