JP7081302B2 - Block polymer - Google Patents

Description

The present invention relates to a block polymer obtained by combining a (meth) acrylic resin and a polyether.

A block polymer is generally a structure in which a plurality of polymer units having different properties for a specific physical property such as solubility are linked, and utilizes properties such as micelle formation in a solution and phase separation structure formation in a bulk. Therefore, it has been widely studied in the fields of adhesives, elastomers, functional pigment dispersants, compatibilizers, drug delivery systems and the like.

As such a polymer unit, an acrylic material is preferably used because it has a large degree of freedom in selecting a monomer and a block polymer structure can be obtained relatively easily by using a living polymerization method. Acrylic block polymers such as diblock polymers and triblock polymers in which three different types of acrylic units are connected to each other are used.

However, the acrylic block polymer obtained by the living polymerization method is generally limited to the block structure of acrylic units due to the characteristics of the manufacturing method, and it is difficult to combine the acrylic block polymer with a polymer unit other than acrylic.

On the other hand, for example, Patent Document 1 discloses a method of introducing a functional group at the end of an acrylic unit for the purpose of adding new value to the acrylic polymer obtained by the living polymerization method. By using such a method, although there is a possibility that it can be linked to a polymer unit other than acrylic starting from the functional group introduced at the end of the acrylic unit, most of the living polymerization methods have a complicated manufacturing process. Further, since it is difficult to effectively remove heavy metals and halogen compounds as catalysts, the applications that can be used especially in the medical field are limited.

Further, the acrylic polymer obtained by the living polymerization method is characterized by having a narrow molecular weight dispersion of 1.0 to 1.2 as compared with ordinary free radical polymerization, but the distribution is distributed in a particle size such as a pigment. In the dispersion of certain fillers and the use of pressure-sensitive adhesives that require high adhesiveness, the uniformity of the polymer structure, which is often derived from the too narrow molecular weight dispersion, and the resulting high microphase separation ability are the dispersibility. It may cause defects and poor adhesive strength, and the characteristics of block polymers with high molecular weight dispersion were expected.

Japanese Patent Application Laid-Open No. 2009-215472

An object of the present invention is to provide a novel block polymer obtained by combining a (meth) acrylic resin and a polyether.

The present invention is a block polymer in which a (meth) acrylic resin unit (A) and a polyether unit (B) are linked, and the molecular weight dispersion of the (meth) acrylic resin unit (A) is 1.25 or more. It relates to a block polymer characterized by.

The present invention also relates to the block polymer, wherein the (meth) acrylic resin unit (A) and the polyether unit (B) are linked by an amide bond and / or an imide bond.

Further, in the present invention, the chain transfer agent residue introduced into the terminal portion of the (meth) acrylic resin unit (A) forms an amide bond and / or an imide bond with the polyether unit (B). The present invention relates to the block polymer.

The present invention also relates to the block polymer, wherein the chain transfer agent is 2-mercaptosuccinic acid.

INDUSTRIAL APPLICABILITY According to the present invention, it is possible to provide a novel block polymer obtained by combining a (meth) acrylic resin and a polyether, which can be expected to be used as a dispersant, a compatibilizer, a bonding agent, a medical material and the like.

Hereinafter, embodiments of the present invention will be described in detail, but the description of the constituent elements described below is an example (representative example) of the embodiments of the present invention, and the present invention is described as long as the gist thereof is not exceeded. Not specified in the content.

The block polymer obtained by combining the (meth) acrylic resin unit (A) and the polyether unit of the present invention is a block polymer in which the (meth) acrylic resin unit (A) and the polyether unit are linked to each other. As long as the degree of molecular weight dispersion of the meta) acrylic resin unit (A) is 1.25 or more, there is no particular limitation, and two or more types of each unit can be used.

The block polymer may be a multi-block polymer as well as a diblock polymer or a triblock polymer.

As a component of each unit constituting the block polymer, for example, a known (meth) acrylic monomer used for (meth) acrylic polymerization, a known polyether having an active hydrogen group, or the like can be used.

The method for connecting the (meth) acrylic resin unit (A) and the polyether unit (B) is not particularly limited, but is preferably a connection by an amide bond and / or an imide bond. More preferably, the chain transfer agent residue introduced at the end of the (meth) acrylic resin unit (A) forms an amide bond and / or an imide bond with the polyether unit (B). Is. As the chain transfer agent, a compound having two carboxyl groups and one or more thiol groups in the molecule is preferable.

The compound having two carboxyl groups and one or more thiol groups in the molecule is not limited to the following examples, and specifically, 2-mercaptosuccinic acid, 2-mercaptoglutaric acid, and 2,2-methylenebis. (Thioglycolic acid), 2,3-dimercaptosuccinic acid, 4,5-dimercaptophthalic acid and the like can be mentioned, and 2-mercaptosuccinic acid is particularly preferable.

As a linking method using the residue of the chain transfer agent, for example, after polymerizing the (meth) acrylic monomer by a known chain transfer polymerization reaction using 2-mercaptosuccinic acid, two 2-mercaptosuccinic acid residues are used. The carboxyl group is acid anhydrideized by a known acid anhydride reaction to obtain a (meth) acrylic polymer having an acid anhydride group at one end, and the obtained (meth) acrylic weight having an acid anhydride group at one end. By condensing the coalescence with a polyether having an active hydrogen group, a block polymer in which the (meth) acrylic resin unit (A) and the polyether unit (B) are linked can be obtained.

When an acid anhydride group is used as a linking site, the link between the (meth) acrylic resin unit (A) and the polyether unit (B) becomes an amide bond or an imide bond, which is chemically compared to an ester bond or the like. It is preferable because it is stable.

As the chain transfer reaction using a chain transfer agent, a chain transfer reaction using a known thiol compound can be used. For example, in the presence of a (meth) acrylic monomer and a chain transfer agent, a radical polymerization initiator is added. By carrying out the radical polymerization reaction at a reaction temperature of about 60 to 150 ° C., an acrylic polymer having a chain transfer agent residue at the end can be obtained. The reaction may be carried out without a solvent, but it is preferable to use a solvent because the viscosity can be easily controlled.

The (meth) acrylic monomer is not limited to the following examples, and is, for example, methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, butyl (meth) acrylate, isobutyl (meth) acrylate, and pentyl (meth). Meta) acrylate, hexyl (meth) acrylate, cyclohexyl (meth) acrylate, decyl (meth) acrylate, dodecyl (meth) acrylate, myristyl (meth) acrylate, palmityl (meth) acrylate, stearyl (meth) acrylate, behenyl (meth) Alkyl (meth) acrylates such as acrylate;
Dimethylaminoethyl (meth) acrylate, dimethylaminopropyl (meth) acrylate, dimethylaminobutyl (meth) acrylate, diethylaminoethyl (meth) acrylate, diethylaminopropyl (meth) acrylate, dipropylaminoethyl (meth) acrylate, dibutylaminoethyl Aminoalkyl (meth) acrylates such as (meth) acrylate;
Dimethylaminoethyl (meth) acrylamide, dimethylaminopropyl (meth) acrylamide, dimethylaminobutyl (meth) acrylamide, diethylaminoethyl (meth) acrylamide, diethylaminopropyl (meth) acrylamide, dipropylaminoethyl (meth) acrylamide, dibutylaminoethyl Aminoalkyl (meth) acrylamides such as (meth) acrylamide;
Polyalkylene glycol mono (meth) acrylates (meth) acrylates having an alkylene oxide chain such as monoalkyl ether;

By product name, polydimethylsiloxane (meth) acrylates such as Silaplane FM-0711 and Silaplane FM-0721 ((all manufactured by Chisso Co., Ltd.);
By product name, Cheminox FAAC-4, Cheminox FAAC-6, Cheminox FAMAC-4, Cheminox FAMAC-6 (all manufactured by Unimatec), R-1110, R-1210, R-1420, R-1620, R-5210. , R-5410, R-5610, M-1110, M-1210, M-1420, M-1620, M-5210, M-5410, M-5610 (all manufactured by Daikin Co., Ltd.), Light Acrylate FA-108 (above, manufactured by Daikin Co., Ltd.) Fluorine-containing (meth) acrylates such as Kyoeisha Chemical Co., Ltd.), Viscort-3F, Viscort-3FM, Viscort-4F, Viscort-8F, Viscort-8FM (all manufactured by Osaka Organic Chemical Industry Co., Ltd.);
By product name, macromonomer AA-6 (methyl methacrylate-based macromonomer), macromonomer AB-6 (butyl (meth) acrylate-based macromonomer), macromonomer AW-6S (isobutyl (meth) acrylate-based macromonomer), macro Vinyl copolymerization of monomer AS-6 (styrene-based macromonomer), macromonomer AN-6S (styrene / acrylonitrile-based macromonomer), macromonomer AK-5 (dimethylsiloxane-based macromonomer) (all manufactured by Toa Synthetic Co., Ltd.) System macromonomers;
Under the product name, (meth) acrylic acid multimer type (meth) acrylates such as Viscote # 150D (tetrahydrofurfuryl alcohol oligoacrylate) and Viscote # 190D (ethoxydiethylene glycol oligoacrylate) (all manufactured by Osaka Organic Chemical Industry Co., Ltd.);
Benzyl (meth) acrylate, cyclohexyl (meth) acrylate, isobornyl (meth) acrylate, dicyclopentenyl (meth) acrylate, dicyclopentanyl (meth) acrylate, dicyclopentenyloxyethyl (meth) acrylate, ethoxyethyl (meth) Examples thereof include various (meth) acrylates such as acrylate, ethylcarbitol (meth) acrylate, butoxyethyl (meth) acrylate, and cyanoethyl (meth) acrylate. In addition to these, radically polymerizable styrene, vinyl acetate and the like are also used. be able to.
These (meth) acrylic monomers can be appropriately selected according to the purpose of use, and one type may be used alone or two or more types may be used in combination.

Examples of the polymerization initiator include benzoyl peroxide, tert-butyl perbenzoate, cumene hydroperoxide, diisopropyl peroxy dicarbonate, di-n-propyl peroxy dicarbonate, and di (2-ethoxyethyl) peroxy dicarbonate. , Tert-Butylperoxy-2-ethylhexanoate, tert-butylperoxyneodecanoate, tert-butylperoxybivalate, (3,5,5-trimethylhexanoyl) peroxide, dipropionyl peroxide, Organic peroxides such as diacetyl peroxide and
2,2'-Azobisisobutyronitrile, 2,2'-azobis (2-methylbutyronitrile), 1,1'-azobis (cyclohexane1-carbonitrile), 2,2'-azobis (2, 4-Dimethylvaleronitrile), 2,2'-azobis (2,4-dimethyl-4-methoxyvaleronitrile), dimethyl 2,2'-azobis (2-methylpropionate), 4,4'-azobis (2,4-dimethylpropionate) 4-cyanovaleric acid), 2,2'-azobis (2-hydroxymethylpropionitrile), 2,2'-azobis [2- (2-imidazolin-2-yl) propane] and other azo compounds Can be mentioned. These polymerization initiators may be used alone or in combination of two or more.

The solvent is not limited to the following examples, for example, acetone, methyl ethyl ketone, cyclohexanone, methyl acetate, ethyl acetate, propyl acetate, toluene, xylene, anisole, N, N-dimethylformamide, N, N-dimethylacetamide, and the like. Examples thereof include N-methylpyrrolidone, N-vinylpyrrolidone, N-methylcaprolactam, dimethylsulfoxide, tetramethylurea, pyridine, dimethylsulfone, hexamethylsulfoxide, m-cresol, γ-butyrolactone and γ-valerolactone. These solvents may be used alone or in combination of two or more.

The method for acid anhydrideizing the two carboxyl groups which are the chain transfer agent residues at the ends of the obtained (meth) acrylic polymer is not limited to the following examples, but is, for example, anhydrous acetic acid or 2,6-. It can be obtained by intramolecular dehydration condensation using an intramolecular condensation catalyst such as bis [(2,2,6,6-tetramethyl-1-piperidinyl) methyl] phenylboronic acid. Further, a method of intramolecular dehydration condensation under high temperature heating conditions may be used without using a catalyst.

The number average molecular weight (Mn) of the (meth) acrylic resin unit (A) may be appropriately adjusted according to the purpose of use, but is preferably 1,500 to 100,000 from the viewpoint of controlling solubility and viscosity. Is. The (meth) acrylic resin unit (A) includes the residue of the introduced chain transfer agent.

The molecular weight dispersion (Mw / Mn) of the (meth) acrylic resin unit (A) is 1.25 or more, preferably in the range of 1.25 to 5.0. Within this range, solubility and viscosity can be easily controlled.

Examples of the polyether having an active hydrogen group include those having a hydroxyl group or an amino group at the end of a polyether skeleton composed of an alkylene glycol unit having 2 to 4 carbon atoms such as polyethylene glycol, polypropylene glycol and polyoxytetramethylene glycol. However, since the connection portion with the (meth) acrylic resin unit is chemically stable, it is preferable to use a polyether having an amino group at the terminal.

The polyether having a hydroxyl group at the terminal is not particularly limited as long as it has a hydroxyl group at the end of the polyether chain, and is not limited to the following examples. However, a polyether monool, a polyether diol, a polyether triol and the like can be used. It may be a tetrafunctional or higher functional polyether polyol. Specifically, polyethylene glycol, alkoxypolyethylene glycol, polypropylene glycol, branched polypropylene glycol, alkoxypolypropylene glycol, polytrimethylene glycol, branched polytrimethylene glycol, alkoxypolytrimethylene glycol, polytetramethylene glycol, branched polytetramethylene glycol. , Alkoxypolytetramethylene glycol and the like.

The polyether having an amino group at the terminal is not particularly limited as long as it has an amino group at the end of the polyether chain, and is not limited to the following examples, such as polyether monoamine, polyether diamine, and polyether triamine. However, it may be a tetrafunctional or higher functional polyether polyamine. Specifically, in addition to polyethylene glycol monoamine, alkoxypolyethylene glycol monoamine, and polyethylene glycol diamine, the product names are M-600, M-1000, M-2005, M-2070, D-230, D-400, and D-2000. , D-4000, HK-511, ED-600, ED-900, ED-2003, T-403, T-3000, T-5000, XJT-436 (above, Huntsman "JEFFAMIN" series), product name PA series, EA series, CA series, 2-functional group type Amine-PEG type, 4-functional group type Amine-PEG type, 8-functional group type Amine-PEG type, DX-100PA, DX-200 PA, 2 Chain branch type PA type, double branch type CA type, triple branch type Amine PEG type, four chain branch type Amine PEG type, bifunctional heterofunctional group type Hydroxy-PEG-Amine type, Boc-projected -Amino-PEG-Amine (above, "SUNBRIGHT" series manufactured by Nichiyu Co., Ltd.) and the like can be mentioned.

The molecular weight of the polyether having an active hydrogen group is not particularly limited and may be appropriately selected depending on the intended purpose, but is preferably 1,000 to 100,000, and if it is in this range, it varies depending on the block polymerization. The effect of can be expected.

A (meth) acrylic resin by modifying at least a part of the active hydrogen groups in a polyether having an active hydrogen group with an acid anhydride group in a (meth) acrylic polymer having an acid anhydride group at one end. A block polymer in which the unit (A) and the polyether unit (B) are linked can be obtained.

For the reaction between the acid anhydride group in the (meth) acrylic polymer having an acid anhydride group at one end and the active hydrogen group in the polyether having an active hydrogen group, the form of the bond is selected according to the purpose. Usually, the reaction is carried out at 20 ° C. to 110 ° C. to form an amide bond and linked, and further the reaction is carried out at a high temperature of 120 ° C. to 200 ° C. to form an imide bond and linked. The reaction may be carried out without a solvent, but it is preferable to use a solvent because the viscosity can be easily controlled.

When connecting a (meth) acrylic polymer having an acid anhydride group at one end to a polyether having an active hydrogen group, an acid anhydride group in the (meth) acrylic polymer having an acid anhydride group at one end. The ratio of the number of moles of the group to the number of moles of the hydroxyl group or the amino group in the polyether having an active hydrogen group can be appropriately selected according to the purpose of use, but preferably has an acid anhydride group at one end. The number of moles of the acid anhydride group in the (meth) acrylic polymer / the number of moles of the hydroxyl group or amino group in the polyether having an active hydrogen group is 0.3 to 1.0, and if it is in this range, the reaction Easy to control.

The solvent for forming the block polymer is not limited to the following examples, but for example, methanol, ethanol, propanol, diacetone alcohol, acetone, methyl ethyl ketone, cyclohexanone, methyl acetate, ethyl acetate, propyl acetate, toluene and xylene. , Anisol, N, N-dimethylformamide, N, N-dimethylacetamide, N-methylpyrrolidone, N-vinylpyrrolidone, N-methylcaprolactum, dimethylsulfoxide, tetramethylurea, pyridine, dimethylsulfone, hexamethylsulfoxide, m- Examples thereof include cresol, γ-butyrolactone, γ-valerolactone and the like. These solvents may be used alone or in combination of two or more.

The ratio of the (meth) acrylic resin unit (A) in the block polymer may be appropriately adjusted according to the purpose of use, but preferably 10 in 100% by weight of the block polymer, the (meth) acrylic resin unit (A) is used. ~ 80% by weight. Within this range, various effects can be expected by forming a block polymer.

Hereinafter, the present invention will be described in more detail by way of examples, but the following examples do not limit the scope of rights of the present invention in any way. In the examples, "parts" represents "parts by weight" and "%" represents "% by weight".
The methods for measuring the resin solid content concentration, the number average molecular weight (Mn), the weight average molecular weight (Mw), the molecular weight dispersion (PDI), and the acid anhydride price in the examples are as follows.

<Resin solid content concentration>
According to JISK5601-1-2, the resin solid content concentration (%) was defined as the heating residue when measured at a heating temperature of 150 ° C. and a heating time of 20 minutes.
<Number average molecular weight (Mn), weight average molecular weight (Mw), molecular weight dispersion (PDI)>
In a GPC (manufactured by Shodex, GPC-104) equipped with an RI detector, using Shodex GPCLF-604 (manufactured by Shodex) as a column and polystyrene-equivalent molecular weight when THF is used as a developing solvent, a number average molecular weight (manufactured by Shodex). Mn) and weight average molecular weight (Mw) were measured, and the molecular weight dispersion (PDI = Mw / Mn) was calculated.
<Measurement of acid anhydride price>
For the acid anhydride value, a (meth) acrylic polymer having an acid anhydride group at one end is weighed a (g) and then dissolved in xylene, and b (mmol) of octylamine equal to or more than the acid anhydride group is added. By doing so, the acid anhydride group and the primary amino group were reacted. Then, the mixture was cooled to room temperature, and the amount of residual octylamine was quantified by titrating with 0.1 M ethanolic perchloric acid. Assuming that the titration amount is c (ml), the acid anhydride value X of the (meth) acrylic polymer having an acid anhydride group at one end can be obtained from the following formula.
X = (b-0.1 × c) / a

The abbreviations of the compounds used in the examples are as follows.
PGMEA: Propylene Glycol Monomethyl Ether Acetate AIBN: 2,2-Azobisisobutyronitrile MMA: Methyl Methacrylate GL2-200PA: Product Name "SUNBRIGHT GL2-200PA" (Polyether Monoamine, manufactured by NOF Corporation, molecular weight 20,000)
DE-100PA: Product name "SUNBRIGHT DE-100PA" (polyester monoamine, manufactured by NOF CORPORATION, molecular weight 10,000)
MEPA-50H: Product name "SUNBRIGHT MEPA-50H" (polyester monoamine, manufactured by NOF CORPORATION, molecular weight 5,000)
DE-200PA: Product name "SUNBRIGHT DE-200PA" (polyester diamine, manufactured by NOF CORPORATION, molecular weight 20,000)
PTE-100PA: Product name "SUNBRIGHT PTE-100PA" (polyester tetraamine, manufactured by NOF CORPORATION, molecular weight 10,000)
DMF: N, N-dimethylformamide

(Synthesis Example 1) <Synthesis of (meth) acrylic resin unit (A-1)>
832 parts of PGMEA and 800 parts of MMA were placed in a reaction vessel equipped with a gas introduction tube, a thermometer, a condenser, and a stirrer, and replaced with nitrogen gas. The reaction vessel was heated to 80 ° C., 24.0 parts of 2-mercaptosuccinic acid and 8.0 parts of AIBN were added, and the reaction was carried out for 12 hours. It was confirmed by solid content measurement that 95% had reacted.
After cooling the obtained solution to 50 ° C., 16.3 parts of acetic anhydride was charged in a reaction vessel and reacted at 100 ° C. for 9 hours. By measuring the acid anhydride price, the reaction was carried out until the terminal dicarboxylic acid of 95% or more of the chain transfer agent became acid anhydride. The obtained (meth) acrylic resin unit (A-1) solution has a resin solid content concentration of 50%, a number average molecular weight of 5,000, a weight average molecular weight of 9,000, and a molecular weight dispersion of 1. It was 8.

(Synthesis Example 2) <Synthesis of (meth) acrylic resin unit (A-2)>
The same operation as in Synthesis Example 1 was carried out except that the blending amounts of 2-mercaptosuccinic acid and acetic anhydride were changed to 40.0 parts and 27.2 parts, respectively. The obtained (meth) acrylic resin unit (A-2) solution has a resin solid content concentration of 50%, a number average molecular weight of 3,000, a weight average molecular weight of 4,500, and a molecular weight dispersion of 1. It was 5.

(Example 1) <Block polymer (AB-1)>
In a reaction vessel equipped with a gas introduction tube, a thermometer, a condenser, and a stirrer, 120 parts of GL2-200PA and 120 parts of DMF were charged and replaced with nitrogen gas. After slowly adding 60 parts of the (meth) acrylic resin unit (A-1) solution while stirring at room temperature, the reaction vessel was heated to 70 ° C., and 1850 cm ^- derived from the acid anhydride group was measured by infrared absorption spectroscopy. The reaction was terminated after confirming the disappearance of absorption of ¹ . The resin solid content concentration of the obtained block polymer (AB-1) solution was 50%, the number average molecular weight was 24,000, and the weight average molecular weight was 50,400.

(Examples 2 to 5) <Block polymers (AB-2) to (AB-5)>
The same operations as in Example 1 were carried out except that the types and blending amounts of the polyether having an active hydrogen group, the (meth) acrylic resin unit, and the solvent were changed as shown in Table 1, and the block polymers (AB-2) to ( AB-5) was obtained. Table 1 shows the resin solid content concentration, the number average molecular weight, and the weight average molecular weight of the obtained block polymers (AB-2) to (AB-5).

<Evaluation of block polymer>
In order to confirm the formation of the block polymer, the solution of the block polymer obtained in Examples 1 to 5, the solution of the (meth) acrylic resin unit obtained in Synthesis Examples 1 and 2, and the solution of the (meth) acrylic resin unit were used in Examples 1 to 5. The following solubility test was carried out on the polyether having an active hydrogen group. The determination results are shown in Table 2.
(Solubility)
The obtained resin solution and the polyether having an active hydrogen group were diluted with methanol so that the solid content concentration of the resin was 1%, and the determination was made according to the following evaluation criteria.
◯: Completely dissolved.
Δ: Precipitation and agglomerates are slightly generated.
X: Insoluble.

The diblock polymer obtained in Examples 1 to 3, the triblock polymer obtained in Examples 4 to 5, and the polyether having an active hydrogen group used in Examples 1 to 5 are all soluble in methanol. On the other hand, since the (meth) acrylic resin unit obtained in Synthesis Examples 1 and 2 is insoluble in methanol, the effect of the (meth) acrylic resin unit being linked to the polyether unit having an active hydrogen group is sufficient. , It was confirmed that it was solubilized in methanol.

Claims (2)

It is a block polymer in which a (meth) acrylic resin unit (A) and a polyether unit (B) are linked , which is represented by the following general formula (1) or (2), and is a block polymer of the (meth) acrylic resin unit (A). A block polymer characterized by having a molecular weight dispersion of 1.25 or more.
General formula (1)

General formula (2)

General formula (3)

[In the general formulas (1), (2) and (3),
(A) is a (meth) acrylic resin unit.
(B) is a polyether unit, which is a polyether unit.
Y ¹ is a hydrogen atom,
In Y ² and Y ³ , one of them is a substituent represented by the above general formula (3), and the other is a carboxyl group.
M ¹ is -NH- or -O-. ] A method for producing a block polymer in which a (meth) acrylic resin unit (A) and a polyether unit (B) are linked.
A step of polymerizing a (meth) acrylic monomer by a chain transfer polymerization reaction using 2-mercaptosuccinic acid to synthesize a (meth) acrylic polymer, and a step of synthesizing the (meth) acrylic polymer.
A step of synthesizing a (meth) acrylic polymer having an acid anhydride group at one end by acid anhydrideizing the two carboxyl groups of the 2-mercaptosuccinic acid residue in the (meth) acrylic polymer by an acid anhydride reaction. When,
It comprises a step of condensing a (meth) acrylic polymer having an acid anhydride group at one end and a polyether having an active hydrogen group.
A method for producing a block polymer, wherein the (meth) acrylic resin unit (A) has a molecular weight dispersion of 1.25 or more.