JP2006312694A - Method for preparing block copolymer and block copolymer obtained thereby - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method using a living radical polymerization for preparing an acrylic block copolymer comprising a methacrylic polymer block and an acrylic polymer block, whereby the acrylic block copolymer excellent in productivity and quality can be stably obtained. <P>SOLUTION: First, an acrylic monomer composing the acrylic polymer block (b) is polymerized, and when its calculated conversion rate becomes 97.0% or higher but lower than 100%, a methacrylic monomer composing the methacrylic polymer block (a) is added to the reaction system and polymerized. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a method for producing an acrylic block copolymer that can be used as a thermoplastic elastomer or as an additive for rubber, thermoplastic resin, and the like, and an acrylic block copolymer obtained by the method.

  As a method for producing an acrylic block copolymer containing a methacrylic polymer block and an acrylic polymer block, a method using living polymerization is generally known.

  Living polymerization, in a narrow sense, refers to polymerization in which the terminal always has activity, but in general, pseudo-living polymerization in which the terminal is inactivated and the terminal is in equilibrium is also known. included. Living anionic polymerization and living radical polymerization are mentioned as living polymerization. Of these, living radical polymerization is preferred from the viewpoints of the number of polymerizable monomers and mild reaction conditions.

  Living radical polymerization is radical polymerization that maintains the activity of the polymerization terminal without loss, and has been actively studied in various groups in recent years.

  Examples include those using chain transfer agents such as polysulfides, those using radical scavengers such as cobalt porphyrin complexes and nitroxide compounds (Non-Patent Documents 1 and 2), organic halides and the like as transition metal complexes. As a catalyst, atom transfer radical polymerization (ATRP) can be used. Among these, atom transfer radical polymerization is attracting attention as a polymerization method suitable for industrialization from the viewpoint of ease of control (Patent Document 1).

  These methods generally have a very high polymerization rate, and are radical polymerizations in which termination reactions such as coupling between radicals are likely to occur, but the polymerization proceeds in a living manner, and Mw / Mn = 1. A polymer of about 1 to 1.5 is obtained. The molecular weight can be freely controlled by the charging ratio of the monomer and the initiator. In addition, in living radical polymerization, the activity of the polymerization terminal is maintained without loss, so it is easy to add a different monomer when the polymerization of the first added monomer is completed or during the polymerization. Block copolymers can be produced.

"Journal of American Chemical Society (J. Am. Chem. Soc.)", 1994, 116, 7943. "Macromolecules", 1994, 27, 7228 Japanese National Patent Publication No. 10-509475

  In general, as a method for producing an acrylic block copolymer by living radical polymerization, a method of sequentially adding monomers, a method of polymerizing the next polymer block using a previously synthesized polymer as a polymer initiator, A method of bonding polymer blocks polymerized to each other by a reaction and the like are mentioned, and from the viewpoint of simplicity of production process and productivity, a method by sequential addition of monomers is preferable.

  However, in the case of the method of sequentially adding the monomers, for example, the unreacted monomer among the monomers polymerized first is mixed in the monomer component to be polymerized next. There may be a problem that the polymer block exhibits physical properties different from those of the polymer block consisting only of the added monomer. In addition, when industrialized, it takes time to add a monomer and the like, but as a result, there arises a problem that the conversion rate of the monomer to be polymerized first cannot be accurately controlled. Thereby, the variation in the amount of the monomer mixed in the next polymer block becomes large, and there arises a problem that the physical properties of the obtained polymer vary.

  On the other hand, when the conversion rate of the monomer first polymerized is 100%, the physical properties tend to deteriorate due to unfavorable reactions such as radical coupling and disproportionation.

  In the production of an acrylic block copolymer comprising a methacrylic polymer block and an acrylic polymer block, the present inventors have calculated that the conversion rate of the monomer added first is 97.0% or more and 100% in calculation. It was found that an acrylic block copolymer having the desired composition can be stably produced by adding a monomer component constituting the next block to the system, and the invention has been completed. .

That is, the present invention relates to a method of sequentially polymerizing an acrylic block copolymer (c) comprising a methacrylic polymer block (a) and an acrylic polymer block (b) using living radical polymerization. Acrylic monomer constituting the polymer block (b) is polymerized, and a value of ln (M ₀ / M _t ) with respect to the polymerization time t (however, the initial concentration of the acrylic monomer is M ₀ , The concentration of the monomer at time t is expressed as M _t ), and the conversion of the acrylic monomer is calculated to be a predetermined value of 97.0% or more and less than 100%. The acrylic block copolymer (c) is produced by adding a methacrylic monomer constituting the methacrylic polymer block (a) to the reaction system and polymerizing the methacrylic polymer block (a). About

As a preferred embodiment, the above production method wherein the acrylic block copolymer (c) is a triblock copolymer or a diblock copolymer,
The above production method wherein the number average molecular weight of the acrylic block copolymer (c) is 10,000 to 500,000,
The ratio (Mw / Mn) of the weight average molecular weight (Mw) to the number average molecular weight (Mn) measured by gel permeation chromatography of the acrylic block copolymer (c) is 1.8 or less. Manufacturing method,
The above production method, wherein the living radical polymerization is atom transfer radical polymerization,
The above production method is an atom transfer radical polymerization in which the living radical polymerization uses a transition metal complex having copper as a central metal as a catalyst.

  Another embodiment is an acrylic block copolymer (c) produced by the above production method.

  According to the production method of the present invention, an acrylic block copolymer having a target composition can be stably produced. The acrylic block copolymer produced by the production method of the present invention can be suitably used as an additive for thermoplastic elastomers and rubbers and thermoplastic resins.

  In the following, the present invention will be described in more detail.

<Method for Producing Acrylic Block Copolymer (c)>
In general, as a method for producing an acrylic block copolymer (c) by living radical polymerization, a method in which monomers are sequentially added, a polymer synthesized in advance is used as a polymer initiator, and the next polymer block is polymerized. Examples thereof include a method and a method in which polymer blocks separately polymerized are combined by reaction. In the present invention, a method by sequential addition of monomers is used from the viewpoint of simplicity of the production process.

  In the method for producing the acrylic block copolymer (c) by the sequential addition of monomers, the methacrylic monomer constituting the methacrylic polymer block (a) and the acrylic polymer block (b) ) For the addition order of acrylic monomers, the method of adding acrylic monomers after first polymerizing methacrylic monomers, and the methacrylic after first polymerizing acrylic monomers Although the method of adding a system monomer is mentioned, in the present invention, the latter is used. The reason is that, as will be described later, it is preferable from the viewpoint of polymerization control to polymerize the methacrylic polymer block (a) from the polymerization terminal of the acrylic polymer block (b).

  On the other hand, various problems arise in the method of sequentially adding monomers. For example, the unreacted monomer among the acrylic monomers added first is mixed into the methacrylic monomer added next. As a result, since the composition of the generated methacrylic polymer block (a) is a copolymer of the added methacrylic monomer and the mixed acrylic monomer, the added methacrylic monomer It may have different physical properties from a polymer block composed only of a body. In addition, when the conversion rate of the acrylic monomer added first cannot be accurately controlled, the variation in the amount of the unreacted acrylic monomer mixed in the next methacrylic polymer block (a) increases. The polymer as designed cannot be obtained.

  In the present invention, the methacrylic monomer is added and polymerized when the conversion rate of the acrylic monomer to be polymerized is 97.0% or more and less than 100% in the calculation described below. By doing so, the above problem can be solved.

  That is, by setting the set cut conversion rate of the acrylic monomer to 97.0% or more and less than 100%, the amount of unreacted acrylic monomer is suppressed to 3.0% or less with respect to the charged amount. be able to. As a result, it has been found that the change in physical properties when this unreacted acrylic monomer is mixed into the methacrylic polymer block (a) can be reduced. Also, by setting the set cut conversion rate of the acrylic monomer to a value of 97.0% or more and less than 100%, the deviation between the actual cut conversion rate and the set cut conversion rate of the acrylic monomer is reduced. That is, it becomes easy to control the actual cut conversion rate very accurately. This can be explained as follows. The set cut conversion rate is the conversion rate of the acrylic monomer at the time when the methacrylic monomer is added, and means a preset value. The actual cut conversion rate means the conversion rate of the acrylic monomer when the methacrylic monomer is actually added.

The conversion rate (%) is obtained by (M ₀ −M _t ) / M ₀ × 100, where the initial concentration of the monomer is represented by M ₀ and the concentration at a certain time is represented by M _t . Further, in the living radical polymerization, when plotted against time the value of _{ln (M 0 / M t)} , it has the characteristics as a straight line passing through the origin. Therefore, by sampling the content liquid during the polymerization reaction and plotting the value of ln (M ₀ / M _t ) at each time, and extrapolating the straight line, the acrylic monomer is brought to the set cut conversion rate. The time to reach can be calculated in advance. The time when the conversion rate of the acrylic monomer is calculated to be 97.0% or more and less than 100% means that time.

In this case, the increase in the conversion rate per hour becomes more gradual as the conversion rate becomes higher, so it is possible to polymerize the acrylic monomer to a higher conversion rate. This is preferable in that the deviation of the cut conversion rate can be reduced. In other words, since the conversion rate and the ln (M ₀ / M _t ) value are measured by sampling the content liquid during the polymerization reaction, the actual cut conversion rate varies depending on the sampling and measurement errors, the time required for operation, and the like. However, it can be said that the degree of variation can be reduced as the set cut conversion rate is higher.

  An acrylic block copolymer having a desired composition can be stably produced by setting the set cut conversion rate of the acrylic monomer to 97.0% or more and less than 100%, but more preferably It is 98.0-99.5%, More preferably, it is 98.5-99.2%. If it is lower than 97.0%, the amount of unreacted acrylic monomer is more than 3.0%, and the physical properties of the subsequently polymerized methacrylic polymer block (a) tend to be greatly changed. Since the increase in the conversion rate per time is large, the cut conversion rate of the acrylic monomer cannot be accurately controlled. If it is higher than 99.5%, the radicals at the growing ends are likely to react with each other, and therefore, undesirable side reactions such as disproportionation, coupling, and chain transfer are likely to occur, and the control of living polymerization is reduced. There is a tendency that the molecular weight distribution is widened, or the reaction rate is lowered, and the physical properties are thereby lowered. In particular, since the polymer bonded by coupling is thermally weak, the heat-resistant decomposability of the obtained thermoplastic elastomer may be deteriorated. Moreover, there exists a problem that superposition | polymerization becomes long and is unpreferable on production.

  In the present invention, a general living radical polymerization method described in the background art can be used. Of these, it is desirable to use atom transfer radical polymerization from the viewpoint of easy control of the polymerization reaction.

  The case where the reaction is carried out by atom transfer radical polymerization is described below.

  In atom transfer radical polymerization, an organic halide or sulfonyl halide compound is used as an initiator, and a metal complex having a group 7 element, group 8, group 9, group 10, or group 11 element as a central metal in the periodic table is used as a catalyst. Legal (eg, Matyjaszewski et al., Journal of American Chemical Society, J. Am. Chem. Soc., 1995, 117, 5614, Macromolecules. (Macromolecules), 1995, 28, 7901, Science, 1996, 272, 866, or Sawamoto et al., Macromolecules, 1995, 28. Volume, page 1721).

  In the atom transfer radical polymerization method, as the organic halide or sulfonyl halide compound used as an initiator, a monofunctional, difunctional, or polyfunctional compound can be used. These may be appropriately selected according to the purpose, and when producing a diblock copolymer, a monofunctional compound is preferable from the viewpoint of easy availability of an initiator, and an ABA type triblock is preferable. In the case of producing a copolymer or a B-A-B type triblock copolymer, it is preferable to use a bifunctional compound from the viewpoint of the number of reaction steps and time reduction. Moreover, when manufacturing a branched block copolymer, it is preferable to use a polyfunctional compound from the point of shortening of the number of reaction processes and time.

  As the initiator, a polymer initiator can also be used. The polymer initiator is a compound composed of a polymer in which a halogen atom is bonded to the end of a molecular chain among organic halides or sulfonyl halide compounds. Since such a polymer initiator can be produced by a living polymerization method other than the living radical polymerization method, it is characterized in that a block copolymer obtained by bonding polymers obtained by different polymerization methods can be obtained. .

Examples of monofunctional compounds include:
C ₆ H ₅ -CH ₂ X,
_{C 6 H 5 -C (H)} (X) -CH 3,
_{C 6 H 5 -C (X)} (CH 3) 2,
R ⁴ —C (H) (X) —COOR ⁵ ,
R ⁴ —C (CH ₃ ) (X) —COOR ⁵ ,
R ⁴ —C (H) (X) —CO—R ⁵ ,
R ⁴ —C (CH ₃ ) (X) —CO—R ⁵ ,
^{_{R 4 -C 6 H 4 -SO 2}} X
And the like.

In the formula, C ₆ H ₅ represents a phenyl group, and C ₆ H ₄ represents a phenylene group (which may be ortho-substituted, meta-substituted, or para-substituted). R ⁴ represents a hydrogen atom, an alkyl group having 1 to 20 carbon atoms, an aryl group having 6 to 20 carbon atoms, or an aralkyl group having 7 to 20 carbon atoms. X represents chlorine, bromine or iodine. R ⁵ represents a monovalent organic group having 1 to 20 carbon atoms.

Specific examples of the alkyl group having 1 to 20 carbon atoms (including the alicyclic hydrocarbon group) as R ⁴ include, for example, methyl group, ethyl group, propyl group, isopropyl group, n-butyl group, isobutyl group, Examples thereof include t-butyl group, n-pentyl group, n-hexyl group, cyclohexyl group, n-heptyl group, n-octyl group, 2-ethylhexyl group, nonyl group, decyl group, dodecyl group, isobornyl group and the like. Specific examples of the aryl group having 6 to 20 carbon atoms include a phenyl group, a triyl group, a naphthyl group, and the like. Specific examples of the aralkyl group having 7 to 20 carbon atoms include benzyl group and phenethyl group.

Specific examples of the monovalent organic group having 1 to 20 carbon atoms which is R ⁵ include the same groups as R ⁴ .

  Specific examples of the monofunctional compound include, for example, tosyl bromide, methyl 2-bromopropionate, ethyl 2-bromide propionate, butyl 2-bromide propionate, methyl 2-isobutyrate bromide, 2- Examples thereof include ethyl bromide isobutyrate and 2-butyl isobutyrate bromide. Of these, ethyl 2-bromide propionate and butyl 2-bromide propionate are preferable because they are similar to the structure of the acrylate monomer and can easily control polymerization.

As a bifunctional compound, for example,
_{X-CH 2 -C 6 H 4} -CH 2 -X,
X—CH (CH ₃ ) —C ₆ H ₄ —CH (CH ₃ ) —X,
_{X-C (CH 3) 2} -C 6 H 4 -C (CH 3) 2 -X,
X—CH (COOR ⁶ ) — (CH ₂ ) _n —CH (COOR ⁶ ) —X,
_{X-C (CH 3) (} COOR 6) - (CH 2) n -C (CH 3) (COOR 6) -X
X—CH (COR ⁶ ) — (CH ₂ ) _n —CH (COR ⁶ ) —X,
_{X-C (CH 3) (} COR 6) - (CH 2) n -C (CH 3) (COR 6) -X,
_{X-CH 2 -CO-CH 2} -X,
_{X-CH (CH 3) -CO} -CH (CH 3) -X,
_{X-C (CH 3) 2} -CO-C (CH 3) 2 -X,
_{X-CH (C 6 H 5} ) -CO-CH (C 6 H 5) -X,
_{X-CH 2 -COO- (CH 2} ) n-OCO-CH 2 -X,
X—CH (CH ₃ ) —COO— (CH ₂ ) _n —OCO—CH (CH ₃ ) —X,
_{X-C (CH 3) 2} -COO- (CH 2) n -OCO-C (CH 3) 2 -X,
_{X-CH 2 -CO-CO-} CH 2 -X,
_{X-CH (CH 3) -CO} -CO-CH (CH 3) -X,
_{X-C (CH 3) 2} -CO-CO-C (CH 3) 2 -X,
X—CH ₂ —COO—C ₆ H ₄ —OCO—CH ₂ —X,
X—CH (CH ₃ ) —COO—C ₆ H ₄ —OCO—CH (CH ₃ ) —X,
_{X-C (CH 3) 2} -COO-C 6 H 4 -OCO-C (CH 3) 2 -X,
_{X-SO 2 -C 6 H 4} -SO 2 -X
And the like.

In the formula, R ⁶ represents an alkyl group having 1 to 20 carbon atoms, an aryl group having 6 to 20 carbon atoms, or an aralkyl group having 7 to 20 carbon atoms. n represents an integer of 0 to 20. C ₆ H ₅ , C ₆ H ₄ and X are the same as described above.

Specific examples of the alkyl group having 1 to 20 carbon atoms, the aryl group having 6 to 20 carbon atoms, and the aralkyl group having 7 to 20 carbon atoms for R ⁶ include an alkyl group having 1 to 20 carbon atoms for R ⁴ and 6 to 6 carbon atoms. Specific examples of 20 aryl groups and aralkyl groups having 7 to 20 carbon atoms are the same.

  Specific examples of the bifunctional compound include, for example, bis (bromomethyl) benzene, bis (1-bromoethyl) benzene, bis (1-bromoisopropyl) benzene, dimethyl 2,3-dibromosuccinate, and 2,3-dibromosuccinate. Diethyl acetate, dibutyl 2,3-dibromosuccinate, dimethyl 2,4-dibromoglutarate, diethyl 2,4-dibromoglutarate, dibutyl 2,4-dibromoglutarate, dimethyl 2,5-dibromoadipate, 2, Diethyl 5-dibromoadipate, dibutyl 2,5-dibromoadipate, dimethyl 2,6-dibromopimelate, diethyl 2,6-dibromopimelate, dibutyl 2,6-dibromopimelate, dimethyl 2,7-dibromosuberate, 2, , 7-dibromosuberic acid diethyl, 2,7-dibromosuberic acid Such as dibutyl, and the like. Of these, bis (bromomethyl) benzene, diethyl 2,5-dibromoadipate, and diethyl 2,6-dibromopimelate are preferred from the viewpoint of availability of raw materials.

As the multifunctional compound, for example,
_{C 6 H 3 - (CH 2} -X) 3,
_{C 6 H 3 - (CH (} CH 3) -X) 3,
_{C 6 H 3 - (C (} CH 3) 2 -X) 3,
_{C 6 H 3 - (OCO-} CH 2 -X) 3,
_{C 6 H 3 - (OCO-} CH (CH 3) -X) 3,
_{C 6 H 3 - (OCO-} C (CH 3) 2 -X) 3,
_{C 6 H 3 - (SO 2} -X) 3
And the like.

In the formula, C ₆ H ₃ is a trivalent phenyl group (the positions of the three bonding hands may be any of the 1st to 6th positions, and the combination thereof can be appropriately selected), and X is the same as described above. is there.

  Specific examples of the polyfunctional compound include, for example, tris (bromomethyl) benzene, tris (1-bromoethyl) benzene, tris (1-bromoisopropyl) benzene and the like. Of these, tris (bromomethyl) benzene is preferable from the viewpoint of availability of raw materials.

  In addition, when an organic halide or sulfonyl halide compound having a functional group is used in addition to the group for initiating polymerization, a polymer in which a functional group other than the group for initiating polymerization is easily introduced at the terminal or in the molecule is obtained. It is done. Examples of functional groups other than the group that initiates polymerization include alkenyl groups, hydroxyl groups, epoxy groups, amino groups, amide groups, silyl groups, and the like.

  In the organic halide or sulfonyl halide compound that can be used as an initiator, the carbon to which the halogen group (halogen atom) is bonded is bonded to the carbonyl group or the phenyl group, and the carbon-halogen bond is activated. Polymerization starts. The amount of the initiator to be used may be determined from the molar ratio with the monomer in accordance with the required molecular weight of the acrylic block copolymer (c). That is, the molecular weight of the acrylic block copolymer (c) can be controlled by the number of monomers used per molecule of the initiator.

  The transition metal complex used as a catalyst for atom transfer radical polymerization is not particularly limited, but preferred are monovalent and zerovalent copper, divalent ruthenium, divalent iron, and divalent nickel. Complex.

  Among these, a copper complex is preferable from the viewpoint of cost and reaction control. Examples of the monovalent copper compound include cuprous chloride, cuprous bromide, cuprous iodide, cuprous cyanide, cuprous oxide, cuprous perchlorate, and the like. Of these, cuprous chloride and cuprous bromide are preferred from the viewpoint of polymerization control. When a monovalent copper compound is used, 2,2′-bipyridyl and its derivatives (for example, 4,4′-dinolyl-2,2′-bipyridyl, 4,4′-di (5- Noryl) -2,2′-bipyridyl and the like; 1,10-phenanthroline, derivatives thereof (for example, 4,7-dinolyl-1,10-phenanthroline, 5,6-dinolyl- 1,10-phenanthroline-based compounds such as 1,10-phenanthroline); polyamines such as tetramethylethylenediamine (TMEDA), pentamethyldiethylenetriamine, and hexamethyl (2-aminoethyl) amine may be added as a ligand. .

A tristriphenylphosphine complex of divalent ruthenium chloride (RuCl ₂ (PPh ₃ ) ₃ ) is also preferable as a catalyst. When a ruthenium compound is used as a catalyst, aluminum alkoxides may be added as an activator. Furthermore, a divalent iron bistriphenylphosphine complex (FeCl ₂ (PPh ₃ ) ₂ ), a divalent nickel bistriphenylphosphine complex (NiCl ₂ (PPh ₃ ) ₂ ), and a divalent nickel bistributylphosphine A complex (NiBr ₂ (PBu ₃ ) ₂ ) is also preferable as a catalyst.

  The transition metal complex and the ligand may be mixed in advance before starting the reaction, or may be appropriately added during the reaction.

  The amount of catalyst and ligand to be used may be determined from the relationship between the amount of initiator, monomer and solvent to be used and the required reaction rate. For example, when trying to obtain a polymer with a high molecular weight, the initiator / monomer ratio must be smaller than when trying to obtain a polymer with a low molecular weight. The reaction rate can be increased by increasing the amount of the catalyst and the ligand. In addition, when a polymer having a glass transition point higher than room temperature is produced, the reaction rate tends to decrease when an organic solvent is added to lower the viscosity of the system and increase the stirring efficiency. In such a case, the reaction rate can be increased by increasing the amount of the catalyst and the ligand.

  The atom transfer radical polymerization can be carried out in the absence of a solvent (bulk polymerization) or in various solvents. When a solvent is used, the amount used may be appropriately determined from the relationship between the viscosity of the entire system and the required stirring efficiency.

  Examples of the solvent include hydrocarbon solvents, ether solvents, halogenated hydrocarbon solvents, ketone solvents, alcohol solvents, nitrile solvents, ester solvents, carbonate solvents, and the like.

  Examples of the hydrocarbon solvent include benzene and toluene. Examples of ether solvents include diethyl ether and tetrahydrofuran. Examples of the halogenated hydrocarbon solvent include methylene chloride and chloroform. Examples of the ketone solvent include acetone, methyl ethyl ketone, methyl isobutyl ketone, and the like. Examples of the alcohol solvent include methanol, ethanol, propanol, isopropanol, n-butanol, t-butanol and the like. Examples of nitrile solvents include acetonitrile, propionitrile, benzonitrile and the like. Examples of the ester solvent include ethyl acetate and butyl acetate. Examples of the carbonate solvent include ethylene carbonate and propylene carbonate. These can be used alone or in combination of two or more. Of these, acetonitrile and toluene are preferably used.

  As the acrylic monomer, various monomers described later can be used, and can be appropriately selected according to required physical properties and reactivity.

  The polymerization method of the acrylic polymer block (b) is not particularly limited, but the temperature is increased after all of the initiator, transition metal complex (ligand as necessary), polymerization solvent, and acrylic monomer are mixed. In this case, the reaction may be started, or the temperature may be increased by mixing other than one kind of raw materials, and then the remaining raw materials may be added. In addition, it is preferable that reaction temperature shall be 20-200 degreeC, and it is more preferable to set it as 50-150 degreeC.

  When the polymerization reaction proceeds and the conversion rate of the acrylic monomer becomes 97.0% or more and less than 100% in the above calculation, a methacrylic polymer block is further added by adding a methacrylic monomer. (A) is polymerized.

  As the methacrylic monomer to be used, various monomers described later can be used, and can be appropriately selected according to required physical properties and reactivity.

  At this time, a transition metal complex can be further added. The transition metal complex to be added may be the same as or different from the transition metal complex used during the polymerization of the acrylic monomer, but cuprous bromide was used for the polymerization of the acrylic monomer. In some cases, it is preferable to add cuprous chloride. From the viewpoint of reaction control, it is preferable that the growing terminal has a carbon-bromine bond in the polymerization of an acrylic monomer, but has a carbon-chlorine bond in the polymerization of a methacrylic monomer. This is because the carbon-bromine bond at the terminal of the acrylic polymer polymerized first can be converted into a carbon-chlorine bond. Here, since the carbon-chlorine bond is more stable than the carbon-bromine bond, the above conversion proceeds efficiently, but the reverse conversion is difficult. Therefore, as described above, the acrylic block copolymer cannot be produced with good control in the order in which the methacrylic monomer is first polymerized and then the acrylic monomer is added.

  If necessary, when adding a methacrylic monomer or during polymerization, a polymerization solvent is added to lower the viscosity of the reaction solution to increase the stirring efficiency, and a ligand is added to increase the reaction rate. Can be added. The polymerization solvent and the ligand used may be the same as or different from those used during the polymerization of the acrylic monomer.

  The conversion rate at which the polymerization of the methacrylic monomer is terminated is not particularly limited, but may be determined from the time required for the reaction, physical properties, raw material costs, and the like.

  The reaction liquid obtained by polymerization contains a mixture of a polymer and a transition metal complex. In order to remove this, an organic acid containing a carboxyl group or a sulfonyl group can be added. By adding an organic acid, a salt with a transition metal complex can be formed, and the salt can be removed by filtration or the like. Subsequently, impurities such as organic acids remaining in the solution are removed by adsorption treatment using basic active alumina, basic adsorbent, solid inorganic acid, anion exchange resin, cellulose anion exchanger, etc. A polymer solution can be obtained.

  The polymer solution thus obtained subsequently removes the polymerization solvent and unreacted monomers by an evaporation operation. Thereby, an acrylic block copolymer (c) can be isolated. As an evaporation method, a thin film evaporation method, a flash evaporation method, a horizontal evaporation method provided with an extrusion screw, or the like can be used.

<Acrylic block copolymer (c)>
The structure of the acrylic block copolymer (c) produced by the method according to the present invention may be either a linear block copolymer, a branched (star) block copolymer, or a mixture thereof. Good. The structure of such a block copolymer is appropriately selected according to the required physical properties of the acrylic block copolymer, but a linear block copolymer is preferred in terms of cost and ease of polymerization. .

  The linear block copolymer may have any structure. From the viewpoint of the physical properties of the linear block copolymer and the composition, the methacrylic polymer block (a) is a, acrylic. When the polymer block (b) is expressed as b, from the viewpoint of easy handling during processing and physical properties of the composition, an ab type diblock copolymer and an abb type triblock copolymer Polymers or mixtures thereof are preferred.

  The molecular weight of the acrylic block copolymer (c) is preferably 10,000 to 500,000 in terms of number average molecular weight, and more preferably 20,000 to 300,000. If the number average molecular weight is less than 10,000, the mechanical strength tends to decrease. When the number average molecular weight is larger than 500,000, processability tends to be lowered. The molecular weight can be set while adjusting the balance with the glass transition temperature described later according to the properties required for the acrylic block copolymer. The molecular weight shown here is a molecular weight measured by polystyrene conversion by gel permeation chromatography (GPC) using a polystyrene gel column with chloroform as a mobile phase.

  Although the ratio (Mw / Mn) of the weight average molecular weight (Mw) and the number average molecular weight (Mn) measured by GPC of the acrylic block copolymer (c) is not particularly limited, it is preferably 1.8 or less. When Mw / Mn exceeds 1.8, the uniformity of the acrylic block copolymer (c) tends to be lowered.

  The composition ratio of the methacrylic polymer block (a) and the acrylic polymer block (b) constituting the acrylic block copolymer (c) is 5 to 95% by weight for (a) and 95 for (b). It can be arbitrarily set in the range of ˜5% by weight. When the proportion of (a) is small, the shape tends to be difficult to be maintained during molding, and when the proportion of (b) is small, the elasticity and meltability during molding tend to decrease. From the viewpoint of hardness, when the proportion of (a) is large, the hardness is high, and when the proportion of (b) is large, the hardness tends to be low. These can be set according to the properties required for the acrylic block copolymer (c).

<Methacrylic polymer block (a)>
The methacrylic polymer block (a) is 50-100% by weight of methacrylic acid ester, preferably 75-100% by weight, and 0-50% by weight of vinyl monomer copolymerizable therewith, preferably 0. It is composed of ˜25% by weight. When the ratio of the methacrylic acid ester is small, characteristics such as weather resistance, high glass transition point, and compatibility with the resin, which are characteristics of the methacrylic acid ester, tend to be impaired.

  Examples of the methacrylate ester include methyl methacrylate, ethyl methacrylate, n-propyl methacrylate, n-butyl methacrylate, t-butyl methacrylate, isobutyl methacrylate, and n-methacrylate. Pentyl, n-hexyl methacrylate, n-heptyl methacrylate, n-octyl methacrylate, 2-ethylhexyl methacrylate, nonyl methacrylate, decyl methacrylate, dodecyl methacrylate, stearyl methacrylate, etc. Methacrylic acid aliphatic hydrocarbon (e.g., alkyl having 1 to 18 carbon atoms); methacrylic acid alicyclic hydrocarbon ester such as cyclohexyl methacrylate and isobornyl methacrylate; methacrylic acid such as benzyl methacrylate Aralkyles Methacrylic acid aromatic hydrocarbon ester such as phenyl methacrylate and toluyl methacrylate; functional group having methacrylic acid and etheric oxygen such as 2-methoxyethyl methacrylate and 3-methoxybutyl methacrylate Esters with containing alcohols; trifluoromethyl methacrylate, trifluoromethyl methyl methacrylate, 2-trifluoromethyl ethyl methacrylate, 2-trifluoroethyl methacrylate, 2-perfluoroethyl ethyl methacrylate, 2-perfluoroethyl-2-perfluorobutylethyl methacrylate, 2-perfluoroethyl methacrylate, perfluoromethyl methacrylate, diperfluoromethyl methyl methacrylate, 2-perfluoromethyl methacrylate 2-pa Trifluoroethyl methyl, methacrylic acid 2-perfluorohexylethyl, meta 2- perfluorodecyl acrylate, etc. methacrylic acid fluorinated alkyl esters such as meta 2-perfluoro-hexadecyl acrylate and the like. Among these, methyl methacrylate is preferable from the viewpoints of weather resistance, low cost, availability, and the like.

  Examples of vinyl monomers copolymerizable with the methacrylic acid ester constituting the methacrylic polymer block (a) include, for example, acrylic acid esters, aromatic alkenyl compounds, vinyl cyanide compounds, conjugated diene compounds, Examples thereof include halogen-containing unsaturated compounds, silicon-containing unsaturated compounds, unsaturated carboxylic acid compounds, unsaturated dicarboxylic acid compounds, vinyl ester compounds, maleimide compounds, and the like.

  Examples of the acrylate ester include methyl acrylate, ethyl acrylate, n-propyl acrylate, n-butyl acrylate, t-butyl acrylate, isobutyl acrylate, n-pentyl acrylate, and n-hexyl acrylate. Acrylate aliphatic hydrocarbons such as n-heptyl acrylate, n-octyl acrylate, 2-ethylhexyl acrylate, nonyl acrylate, decyl acrylate, dodecyl acrylate, stearyl acrylate (for example, having 1 to 18 carbon atoms) Alkyl) esters; acrylic acid alicyclic hydrocarbon esters such as cyclohexyl acrylate and isobornyl acrylate; acrylic acid aromatic hydrocarbon esters such as phenyl acrylate and toluyl acrylate; aralkyl acrylates such as benzyl acrylate; Esters of acrylic acid and functional group-containing alcohols having etheric oxygen such as 2-methoxyethyl acrylate and 3-methoxybutyl acrylate; trifluoromethyl methyl acrylate, 2-trifluoromethyl ethyl acrylate, acrylic acid 2-perfluoroethylethyl, 2-perfluoroethyl-2-perfluorobutylethyl acrylate, 2-perfluoroethyl acrylate, perfluoromethyl acrylate, diperfluoromethyl methyl acrylate, 2-perfluoro acrylate Examples thereof include fluorinated alkyl acrylates such as methyl-2-perfluoroethylmethyl, 2-perfluorohexylethyl acrylate, 2-perfluorodecylethyl acrylate, and 2-perfluorohexadecylethyl acrylate.

  Examples of the aromatic alkenyl compound include styrene, α-methylstyrene, p-methylstyrene, p-methoxystyrene, and the like.

  Examples of the vinyl cyanide compound include acrylonitrile and methacrylonitrile.

  Examples of the conjugated diene compound include butadiene and isoprene.

  Examples of the halogen-containing unsaturated compound include vinyl chloride, vinylidene chloride, perfluoroethylene, perfluoropropylene, and vinylidene fluoride.

  Examples of the unsaturated carboxylic acid compound include methacrylic acid and acrylic acid.

  Examples of the unsaturated dicarboxylic acid compound include maleic anhydride, maleic acid, monoalkyl esters and dialkyl esters of maleic acid, fumaric acid, monoalkyl esters and dialkyl esters of fumaric acid, and the like.

  Examples of the vinyl ester compound include vinyl acetate, vinyl propionate, vinyl pivalate, vinyl benzoate, vinyl cinnamate, and the like.

  Examples of the maleimide compound include maleimide, methylmaleimide, ethylmaleimide, propylmaleimide, butylmaleimide, hexylmaleimide, octylmaleimide, dodecylmaleimide, stearylmaleimide, phenylmaleimide, cyclohexylmaleimide and the like.

<Acrylic polymer block (b)>
The acrylic polymer block (b) is an acrylic ester of 50 to 100% by weight, preferably 75 to 100% by weight, and a vinyl monomer copolymerizable therewith 0 to 50% by weight, preferably 0 to 25%. Consists of% by weight. If the proportion of the acrylic ester is less than 50% by weight, the physical properties of the composition, particularly flexibility and oil resistance, which are characteristics when using the acrylic ester, may be impaired.

  As the acrylic ester, those similar to the acrylic ester used in the methacrylic polymer block (a) can be used, but acrylic acid-n-butyl, ethyl acrylate and acrylic acid-2-methoxy are used. Ethyl is preferred. Acrylic acid-n-butyl is preferable in terms of the balance between rubber elasticity, low temperature characteristics and cost. Ethyl acrylate is preferred in terms of oil resistance and mechanical properties. Further, 2-methoxyethyl acrylate is preferable in terms of imparting low temperature characteristics and oil resistance and improving the surface tackiness of the resin.

  Examples of vinyl monomers copolymerizable with the acrylic ester constituting the acrylic polymer block (b) include methacrylic ester, aromatic alkenyl compound, vinyl cyanide compound, conjugated diene compound, halogen, and the like. Examples thereof include a unsaturated compound containing silicon, an unsaturated compound containing silicon, an unsaturated carboxylic acid compound, an unsaturated dicarboxylic acid compound, a vinyl ester compound, and a maleimide compound. These may be the same as those used for the methacrylic polymer block (a).

  EXAMPLES Although this invention is demonstrated further in detail based on an Example, this invention is not limited only to these Examples. In the examples, BA, EA, TBA, MMA, and TBMA each represent -n-butyl acrylate, ethyl acrylate, tert-butyl acrylate, methyl methacrylate, and tert-butyl methacrylate. Moreover, the molecular weight described in the Example and the conversion rate of the polymerization reaction were performed according to the following methods.

<Molecular weight measurement method>
The molecular weight shown in this example was measured by the GPC analyzer shown below, and the molecular weight in terms of polystyrene was determined using chloroform as the mobile phase. As a system, a GPC system manufactured by Waters was used, and Shodex K-804 (polystyrene gel) manufactured by Showa Denko Co., Ltd. was used for the column.

<Method for measuring conversion rate of polymerization reaction>
The conversion rate of the polymerization reaction shown in this example was measured using the following analyzer and conditions.

Equipment used: Gas chromatography GC-14B manufactured by Shimadzu Corporation
Separation column: Capillary column DB-17 manufactured by J & W SCIENTIFIC INC, 0.32 mmφ × 30 m
Separation conditions: Initial temperature 50 ° C, hold for 3 minutes
Temperature increase rate 40 ° C / min
Final temperature 140 ° C, hold for 1.5 minutes
Injection temperature 250 ° C
Detector temperature 250 ° C
Sample preparation: The sample was diluted about 10 times with ethyl acetate, and acetonitrile was used as an internal standard substance.

<Thermogravimetric analysis>
The thermal decomposition resistance shown in the present example was measured at a heating rate of 10.0 ° C. under a nitrogen stream at a flow rate of 50.0 ml / min using a differential thermothermal gravimetric measurement device (DTG-50) manufactured by Shimadzu Corporation. It measured on condition of / min. The weight loss temperature was determined based on the weight at 100 ° C.

Example 1
After charging 228.1 kg of BA and 12.9 kg of TBA in a nitrogen-substituted 2 m ³ reactor in advance, 2.15 kg of copper bromide was added and stirring was started. Subsequently, 3.60 kg of diethyl 2,5-dibromoadipate as an initiator was dissolved in 21.2 kg of acetonitrile, a nitrogen bubbled solution was added, and the internal temperature was heated to 75 ° C. After sampling a small amount of the content solution, 0.26 kg of N, N, N-pentamethyldiethylenetriamine (hereinafter abbreviated as triamine) was added to initiate polymerization. In order to adjust the reaction rate, triamine was appropriately added, and polymerization was performed at an internal temperature of 80 to 90 ° C. The content liquid was sampled at intervals of 30 minutes from the start of polymerization, and the conversion and the ln (M ₀ / M _t ) value were measured by GC measurement. Using the fact that the increment (slope) of the ln (M ₀ / M _t ) value with respect to time is constant, the time when the conversion rate of BA becomes 99.0% was predicted by calculation.

  After sampling at the expected time, 313.4 kg of toluene, 1.48 kg of copper chloride, 145.4 kg of MMA, and 23.6 kg of EA were added. The conversion rate of BA (actual cut conversion rate) obtained from this sampling was 98.7%.

  Immediately after the addition of MMA, a new sampling was performed as a reaction starting point for MMA polymerization. In order to adjust the reaction rate, triamine was appropriately added, and polymerization was performed at an internal temperature of 85 ° C. Thereafter, sampling was performed as appropriate, and when the conversion rate of MMA was 96.0%, 400.0 kg of toluene was added, and the internal temperature was lowered to complete the polymerization.

To the obtained content liquid, 486.6 kg of toluene was added for dilution, 7.7 kg of p-toluenesulfonic acid monohydrate was added, and the mixture was stirred at room temperature. After 3 hours, 8.0 kg of Radiolite # 3000 (manufactured by Showa Chemical Industry Co., Ltd.) was added, and the solid content was filtered off using a pressure filter equipped with a polyester felt (filtration area 0.45 m ² ). Kyoward 500SH (manufactured by Kyowa Chemical Co., Ltd.) (6.0 kg) was added to the obtained filtrate and stirred at room temperature. After 1 hour, the solid content was filtered off using a pressure filter to obtain a colorless and transparent polymer solution.

After adding 0.6 parts by weight of Irganox 1010 (manufactured by Ciba Specialty Chemicals) to 100 parts by weight of the polymer to the obtained polymer solution, SCP100 (manufactured by Kurimoto Steel Works) The solvent component was evaporated using a heat transfer area of 1 m ² ). The heating medium oil at the evaporator inlet was 180 ° C., the evaporator vacuum was 0.01 MPa or less, the screw rotation speed was 60 rpm, and the polymer solution supply rate was 32 kg / h. The polymer was made into a strand through a φ4 mm die, cooled in a water bath, and polymer pellets were obtained by a pelletizer.

  1 part by weight of hydrotalcite DHT4A-2 (manufactured by Kyowa Chemical Co., Ltd.) is added to this pellet, and a twin screw extruder with a vent (44 mm, L / D = 42.55, manufactured by Nippon Steel Works, Ltd.) An acrylic block copolymer obtained by modifying the TBA unit into an acid anhydride unit was obtained by melt kneading at a set temperature of 260 ° C., 150 rpm, and a discharge rate of 15 kg / h (acrylic block copolymer 1). At this time, an underwater cut pelletizer (CLS-6-8.1 COMPACT SYSTEM manufactured by GALA INDUSTRIES INC.) Was connected to the tip of the twin-screw extruder, and Alfro H-50ES (Nippon Oil & Fats Co., Ltd.) was used as an anti-adhesive agent in circulating water. To produce spherical pellets.

  Table 1 summarizes the mechanical properties, number average molecular weight, molecular weight distribution, and cut conversion rate (setting and results) of the acrylic block copolymer 1.

(Example 2)
In the same manner as in Example 1, an acrylic block copolymer 2 was produced. The actual cut conversion rate of BA was 98.9%, and the conversion rate of MMA at the end of the polymerization was 94.5%.

  Table 1 summarizes the mechanical properties, number average molecular weight, molecular weight distribution, and BA cut conversion (setting and performance) of the acrylic block copolymer 2.

(Example 3)
In the same manner as in Example 1, an acrylic block copolymer 3 was produced. The actual cut conversion rate of BA was 99.0%, and the conversion rate of MMA at the end of the polymerization was 95.4%.

  Table 1 summarizes the mechanical properties, number average molecular weight, molecular weight distribution, and BA cut conversion (setting and performance) of the acrylic block copolymer 3.

Example 4
Operation similar to Example 1 except having used BA87.1kg, TBA2.2kg, copper bromide 625g, diethyl 2,5-dibromoadipate 628g, acetonitrile 7.8kg, and triamine 75.5g in a 500 L reactor. The polymerization was started at The point in time when the conversion rate of BA reached 97.0% was predicted by calculation, and 106.6 kg of toluene, 38.4 kg of MMA, and 431 g of copper chloride were added. The actual cut conversion rate of BA at this point was 97.3%. Thereafter, MMA was polymerized in the same manner as in Example 1. When the conversion rate was 89.1%, 220 kg of toluene was added, and the internal temperature was lowered to terminate the polymerization.

  The same operation as in Example 1 except that 75 kg of toluene, 1.5 kg of p-toluenesulfonic acid monohydrate, 2.5 kg of Radiolite # 3000, and 1.9 kg of Kyoward 500SH were used for the obtained content liquid. As a result, pellets of the acrylic block copolymer 4 were obtained.

  Table 1 summarizes the mechanical properties, number average molecular weight, molecular weight distribution, and BA cut conversion rate (setting and results) of the acrylic block copolymer 4.

(Example 5)
In the same manner as in Example 4, an acrylic block copolymer 5 was produced. The actual cut conversion rate of BA was 96.4%, and the conversion rate of MMA at the end of the polymerization was 88.7%.

  Table 1 summarizes the mechanical properties, number average molecular weight, molecular weight distribution, and cut conversion rate (setting and performance) of the acrylic block copolymer 5.

(Comparative Example 1)
After charging 76.0 kg of BA that had been previously bubbled with nitrogen into a 500-liter reactor purged with nitrogen, 622 g of copper bromide was added and stirring was started. Subsequently, 867 g of diethyl 2,5-dibromoadipate initiator was dissolved in 6.6 kg of acetonitrile, a nitrogen bubbled solution was added, and the internal temperature was heated to 75 ° C. After sampling a small amount of the content solution, 75 g of N, N, N-pentamethyldiethylenetriamine (hereinafter abbreviated as triamine) was added to initiate polymerization. In order to adjust the reaction rate, triamine was appropriately added, and polymerization was performed at an internal temperature of 80 to 90 ° C. The content liquid was sampled at intervals of 30 minutes from the start of polymerization, and the conversion and the ln (M ₀ / M) value were measured by GC measurement. Using the fact that the increment (slope) of the ln (M ₀ / M) value with respect to time is constant, the time when the conversion rate of BA is 95.0% was predicted by calculation.

  After sampling at the expected time, 103.6 kg of toluene, 430 g of copper chloride, 42.3 kg of MMA, 3.8 kg of TBMA, and 9.2 kg of BA were added. The conversion rate of BA (actual cut conversion rate) obtained from this sampling was 96.8%.

  Immediately after the addition of MMA, a new sampling was performed as a reaction starting point for MMA polymerization. In order to adjust the reaction rate, triamine was appropriately added, and polymerization was performed at an internal temperature of 85 ° C. Thereafter, sampling was performed as appropriate, and when the MMA conversion rate was 91.3%, 70.0 kg of toluene was added, and the internal temperature was lowered to terminate the polymerization.

To the obtained content liquid, 40.0 kg of toluene was added for dilution, 1.7 kg of p-toluenesulfonic acid monohydrate was added, and the mixture was stirred at room temperature. Three hours later, 2.0 kg of Radiolite # 3000 (manufactured by Showa Chemical Industry Co., Ltd.) was added, and the solid content was filtered off using a pressure filter equipped with a polyester felt (filtration area 0.45 m ² ). 1.5 kg of KYOWARD 500SH (manufactured by Kyowa Chemical Co., Ltd.) was added to the obtained filtrate and stirred at room temperature. After 1 hour, the solid content was filtered off using a pressure filter to obtain a colorless and transparent polymer solution.

After adding 0.6 parts by weight of Irganox 1010 (manufactured by Ciba Specialty Chemicals) to the obtained polymer solution with respect to the weight of the polymer, SCP100 (manufactured by Kurimoto Steel Works, The solvent component was evaporated using a heat transfer area of 1 m ² ). The heating medium oil at the evaporator inlet was 180 ° C., the evaporator vacuum was 0.01 MPa or less, the screw rotation speed was 60 rpm, and the polymer solution supply rate was 32 kg / h. The polymer was made into a strand through a φ4 mm die, cooled in a water bath, and polymer pellets were obtained by a pelletizer.

  1 part by weight of hydrotalcite DHT4A-2 (manufactured by Kyowa Chemical Co., Ltd.) is added to this pellet, and a twin screw extruder with a vent (44 mm, L / D = 42.55, manufactured by Nippon Steel Works, Ltd.) An acrylic block copolymer obtained by modifying the TBMA unit into an acid anhydride unit was obtained by melt kneading at a set temperature of 260 ° C., 150 rpm, and a discharge rate of 15 kg / h (acrylic block copolymer 5). At this time, an underwater cut pelletizer (CLS-6-8.1 COMPACT SYSTEM manufactured by GALA INDUSTRIES INC.) Was connected to the tip of the twin-screw extruder, and Alfro H-50ES (manufactured by Nippon Oil & Fats Co., Ltd.) )) Was added to obtain spherical pellets of the acrylic block copolymer 6.

  Table 1 summarizes the mechanical properties, number average molecular weight, molecular weight distribution, and BA cut conversion (setting and performance) of the acrylic block copolymer 6.

(Comparative Example 2)
In the same manner as in Comparative Example 1, an acrylic block copolymer 7 was produced. The actual cut conversion rate of BA was 95.2%, and the conversion rate of MMA at the end of the polymerization was 91.3%.

  Table 1 summarizes the mechanical properties, number average molecular weight, molecular weight distribution, and BA cut conversion (setting and performance) of the acrylic block copolymer 7.

  As is apparent from Table 1, when an acrylic block copolymer is produced by the sequential addition of monomers, the acrylic monomer to be polymerized first is polymerized to a high conversion rate of 99.0%. Thus, it can be seen that the variation of the actual cut conversion rate of the acrylic monomer can be controlled very accurately within 0.3% within 3 batches. Their mechanical properties are also stable. Similarly, when the acrylic monomer is polymerized to a conversion rate of 97.0%, the variation in the actual cut conversion rate can be controlled with relatively high accuracy within 0.9%.

  On the other hand, when the set cut conversion rate of the acrylic monomer is 95.0% as in Comparative Examples 1 and 2, the actual cut conversion rate is 95.2%, or 96.8%. It can be seen that stable production with low accuracy is difficult, and the mechanical properties, particularly hardness, are increased accordingly.

From the above, it was shown that an acrylic block copolymer having a desired composition can be stably produced by using the production method of the present invention.

Claims (7)

In the method of sequentially polymerizing an acrylic block copolymer (c) comprising a methacrylic polymer block (a) and an acrylic polymer block (b) using living radical polymerization, first, an acrylic polymer block ( b) is polymerized, and the value of ln (M ₀ / M _t ) with respect to the polymerization time t (provided that the initial concentration of the acrylic monomer is M ₀ , the time at time t) the concentration of monomer using a linear obtained by plotting represented) with M _t, when the calculation on the acrylic monomer conversion rate becomes a predetermined value less than 100% 97.0% or more, A method for producing an acrylic block copolymer (c), wherein a methacrylic monomer constituting the methacrylic polymer block (a) is added to the reaction system and polymerized.   The production method according to claim 1, wherein the acrylic block copolymer (c) is a triblock copolymer or a diblock copolymer.   The production method according to claim 1 or 2, wherein the acrylic block copolymer (c) has a number average molecular weight of 10,000 to 500,000.   The ratio (Mw / Mn) of the weight average molecular weight (Mw) to the number average molecular weight (Mn) measured by gel permeation chromatography of the acrylic block copolymer (c) is 1.8 or less. The manufacturing method in any one of 1-3.   The manufacturing method according to any one of claims 1 to 4, wherein the living radical polymerization is atom transfer radical polymerization.   6. The production method according to claim 1, wherein the living radical polymerization is atom transfer radical polymerization using a transition metal complex having copper as a central metal as a catalyst.   The acrylic block copolymer (c) manufactured by the manufacturing method as described in any one of Claims 1-6.