JPH0693060A - Methacrylic block copolymer and its production - Google Patents

Abstract

PURPOSE:To provide a copolymer, a block copolymer made up of syndiotactic polymer block and non-stereoregular polymer block, having a specific molecular weight, excellent in heat resistance and impact resistance or thermoplastic elastomeric properties. CONSTITUTION:The copolymer with a molecular weight of 3000-2000000 having structure of formula I or II (A is syndiotactic polymer block based on a methacrylic 1-31C alkyl ester; B is non-stereoregular polymer block based on an acrylic 1-8C alkyl ester; the molecular weight of the block A is 1000-700000; that of the block B 1000-700000; l is 0-5; m is 1-5). This polymer can be obtained by polymerizing the methacrylic alkyl ester at -100 to +100 deg.C using an organometallic complex the metal being a rare earth metal) as initiator until the conversion rate comes to >=90% followed by adding the acrylic alkyl ester and the methacrylic alkyl ester to the system alternately at least once.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a block copolymer composed of a polymethacrylate block having excellent impact resistance and heat resistance and a polyacrylate block.

[0002]

2. Description of the Related Art Polymethacrylate ester resin (PM
MA) is a resin that is manufactured by radical polymerization and has excellent weather resistance. However, since homopolymer has a low impact strength, impact resistance is improved by blending, for example, a polyacrylate rubber produced by emulsion polymerization. Is given.

However, with this method, the improvement in impact strength is not so great, and PMMA having higher impact resistance has been desired. . Furthermore, the glass transition temperature of PMMA is 10
Since the temperature is around 5 ° C., the heat resistant temperature was raised by copolymerizing with expensive maleimides or imidizing PMMA. However, the appearance of a method that can be manufactured at a lower cost is desired.

As such a method, there can be considered a method of forming a block copolymer having at least one structure in which a highly stereoregular polyacrylic acid alkyl ester is bonded to both ends of a polymethacrylic acid alkyl ester molecule in the molecule. . In order to produce such a block copolymer, both acrylic acid alkyl ester and methacrylic acid alkyl ester undergo living polymerization, and methacrylic acid alkyl ester undergoes stereoregular polymerization, while acrylic acid alkyl ester undergoes stereoregularity. An initiator that does not polymerize is required. Furthermore, if an initiator can be developed in which the acrylic acid alkyl ester undergoes living polymerization at the living polymerization active end of the polymethacrylic acid alkyl ester and, conversely, the methacrylic acid alkyl ester undergoes living polymerization at the living polymerization end of the polyacrylic acid alkyl ester, The block copolymer can be easily produced.

No initiator is known to give such a block copolymer having three or more block moieties.
It is well known that radical initiators such as dicumyl peroxide and t-butyl perbenzoate do not undergo living polymerization of methacrylic acid alkyl esters or acrylic acid alkyl esters, nor do they undergo highly stereoregular polymerization of methacrylic acid alkyl esters. There is.

The silyl ketene acetal / Lewis acid type so-called group transfer polymerization initiator undergoes living polymerization of both methacrylic acid ester and acrylic acid ester, but the obtained polymethacrylic acid ester is not stereoregular (Japanese Patent Laid-Open No. 62-292806). issue). Similarly, porphyrin-organoaluminum complex also undergoes living polymerization with methacrylic acid ester and acrylic acid and ester,
Methacrylic acid ester does not undergo stereoregular polymerization (SI
noue et al.,. Maeromolecule
s, 24 , 824 (1991)).

The Grignard reagent polymerizes alkyl methacrylates in the living room at a low temperature of −70 ° C. or less in the living room with high stereoregularity, but the acrylic acid esters do not undergo living polymerization (T. Kitayayama et al., Makromomo).
1-Chem. Suppl. , 15 , 167 (198
9)). When an organic rare earth metal complex is used as an initiator, both the methacrylic acid ester and the acrylic acid ester undergo living polymerization, and the methacrylic acid ester polymerizes with high stereoregularity (syndiotacticity). On the other hand, when methyl methacrylate is first polymerized and then methyl acrylate is copolymerized, block copolymerization occurs, but conversely, acrylic acid ester is polymerized first, and even if methacrylic acid ester is subsequently added, the block copolymer becomes It was unclear whether or not it could be obtained (JP-A-3-263412, JP-A-2-258808).
No., Fine Chemical Vol. 20, No. 4,5
P. 15; March 1, 1991].

[0008]

[Problems to be Solved by the Invention] A block copolymer having at least one structure in which a highly syndiotactic polymethacrylic acid ester is bound to both ends of a polyacrylic acid ester molecule in the molecule is produced and the heat resistance is improved. And a block copolymer having excellent impact resistance or elastomeric properties.

[0009]

[Means for Solving the Problems] The first aspect of the present invention is to provide a methacrylic acid alkyl ester (having an alkyl group having 1 to 3 carbon atoms).
Based on the syndiotactic polymer block A and an alkyl acrylate (wherein the alkyl group has 1 to
8) A non-stereoregular polymer block (B) containing formula A- (BA) _l- BA or A- (BA) _m- B [In formula, l is an integer of 0-5. , M is an integer of 1 to 5. ] The block copolymer represented by the following formula, wherein the molecular weight of block A is 1,000 to 700,000, and block B is
Has a molecular weight of 1,000 to 700,000, and the entire block copolymer has a molecular weight of 3,000 to 2,000,0.
The present invention provides a methacrylic block copolymer characterized in that it is 00.

In the second aspect of the present invention, an organic rare earth metal complex is used as an initiator at a temperature of -100 ° C to + 100 ° C.
The methacrylic acid alkyl ester is polymerized until the conversion becomes 90% or more, and then the acrylic acid alkyl ester and the methacrylic acid alkyl ester are alternated once or more,
Moreover, when the conversion rate of each is 90% or more, the syndiotactic polymer block A based on the methacrylic acid alkyl ester (the number of carbon atoms of the alkyl group is 1 to 3) is added and polymerized, and the acrylic acid alkyl ester ( The formula A- (BA) _l- BA or A- (BA) _m- B containing the non-stereoregular polymer block (B) whose alkyl group has 1 to 8 carbon atoms [wherein , 1 is an integer of 0 to 5, and m is an integer of 1 to 5. ] The block copolymer represented by the following formula, wherein the molecular weight of block A is 1,000 to 700,000, and block B is
Has a molecular weight of 1,000 to 700,000, and the entire block copolymer has a molecular weight of 3,000 to 2,000,0.
A methacrylic block copolymer of No. 00 is produced, and a method for producing a block copolymer is provided.

[0011]

In the commonly known (coordinating) anionic living polymerization, it is extremely difficult to perform block copolymerization by reversing the order of the polymerization in a block copolymerization of monomers of different types. By using the metal complex as a polymerization initiator, a block copolymer of an alkyl methacrylate and an alkyl acrylate having a wrinkle block of ABA can be produced.

[0012]

DETAILED DESCRIPTION OF THE INVENTION The alkyl methacrylate methyl methacrylate as the alkyl methacrylate, ethyl methacrylate, n- propyl, isopropyl methacrylate can be used. With a methacrylic acid alkyl ester having an alkyl group with 4 or more carbon atoms, the glass transition point of the obtained random copolymer becomes low, and the heat resistance and bending rigidity become low.

However, butyl methacrylate, amyl methacrylate, cyclohexyl methacrylate, pentadecyl methacrylate, etc. may be used as a copolymerization component as long as the object of the present invention is not impaired. Acrylic acid alkyl ester As an acrylic acid alkyl ester, methyl acrylate, ethyl acrylate, n-propyl acrylate, isopropyl acrylate, n-butyl acrylate, isobutyl acrylate, isoamyl acrylate, hexyl acrylate, acrylic acid 2 Ethyl hexylate is available.

The organic rare earth metal compound used as the polymerization initiator for the organic rare earth metal compound is
Divalent or trivalent, preferably trivalent rare earth metal (Group 3A of the periodic table; Sc, Y, La, Ce, Pr, Nd, Pm, S
m, Eu, Gd, Tb, Dy, Ho, Er, Tm, Y
b, Lu) is an organic compound containing a rare earth element. Preferably, formula (I)

[0015]

[Chemical 1]

Or formula (II)

[0017]

[Chemical 2]

[In the formula, R _{1 to} R ₁₀ are a hydrogen atom, a hydrocarbon group having 1 to 5 carbon atoms or a hydrocarbon group containing silicon, and R _{1 to} R ₁₈ are bonded to each other via an adjacent R group and a hydrocarbon group. May be combined with each other. M is Sc, Y, La, Ce, Pr,
Nd, Pm, Sm, Eu, Ga, Tb, Dy, Ho, E
r, Tm, Yb, and Lu. X is a hydrogen atom, a hydrocarbon group having 1 to 10 carbon atoms, or a hydrocarbon group containing diatom. Z is an alkylene group having 1 to 3 carbon atoms or an alkylsilyl group. D is a solvent molecule and n = 0 to 3. ] The complex shown by these is preferable.

Specifically, biscyclopentadienyl lutetium hydride, biscyclopentadienyl lutetium methyl, biscyclopentadienyl lutetium ethyl, biscyclopentadienyl lutetium bistrimethylsilylmethyl, bispentamethylcyclopentadienyl lutetium Hydride, bispentamethylcyclopentadienyl lutetium methyl, bispentamethylcyclopentadienyl lutetium bistrimethylsilylmethyl, biscyclopentadienyl ytterbium hydride, biscyclopentadienyl ytterbium methyl, bispentamethyl cyclopentadi Phenyl ytterbium hydride, bispentamethyl cyclopentadienyl phenyl ytterbium methyl, bispentamethyl cyclopentadiene Rutterbium bistrimethylsilylmethyl, biscyclopentadienyl samarium hydride, biscyclopentadienyl samarium methyl, bispentamethylcyclopentadienyl samarium hydride, bispentamethylcyclopentadienyl samarium methyl, bispentamethylcyclopentadimethyl Enyl samarium bistrimethylsilylmethyl, biscyclopentadienyl europium hydride, biscyclopentadienyl europium methyl, bispentamethylcyclopentadienyl europium hydride, bispentamethylcyclopentadienyl europium methyl, bispentamethylcyclo Pentadienyl neodymium methyl, bispentamethyl cyclopentadienyl cerium hydride, bispentamethyl Clopentadienyl yttrium methyl, bispentamethyl cyclopentadienyl scandium hydride, bispentamethyl cyclopentadienyl scandium methyl, bisindenyl lutetium methyl, ethylene bis indenyl lutetium methyl, ethylene biscyclopentadienyl lutetium methyl, etc. However, the present invention is not limited to these.

In these examples, the solvent molecule D (eg, tetrahydrofuran, THF, diethyl ether, benzene, toluene, etc.) is omitted. These compounds are prepared by known methods (Tobin J. Mark).
S.J. Am. Chem. Soc. 107, 8091,
1985. William. J. Evans, J .; A
m. Chem. Soc. 105,1401,198
3. P .; L. Watson, A .; C. S. Sym
p. , 495, 1983. Tobin J .; Mark
s, WO 8605788). Among them, it is preferable that all of R _{1 to} R _{10 in} the formulas (I) and (II) are methyl groups.

Polymerization Inert gas (nitrogen, argon, helium, etc.) atmosphere, with or without solvent coexisting, -100 ° C to +100.
C., preferably -100.degree. C. to + 50.degree. C., particularly preferably -50.degree. C. to + 25.degree. C., under a pressure of 1 to 50 atm, preferably 1 to 10 atm, particularly preferably 1 to 5 atm. The ester is polymerized until the conversion becomes 90% or more, preferably 95% or more, and then the acrylic acid alkyl ester and then the methacrylic acid alkyl ester are alternately alternated once or more, respectively, and each conversion rate is 90% or more. , Preferably 95% or more, and then added and polymerized.

The amount of the organic rare earth compound used as an initiator varies depending on the desired molecular weight of the block copolymer, but is usually 5 × 10 ^-5 to 1 × 10 ^-1 mol, preferably 1 mol of all the monomers. It is about 3 × 10 ^{−5 to} 2 × 10 ⁻¹ mol. When a solvent is used, halogenated hydrocarbons such as methylene chloride, chloroform and carbon tetrachloride; aromatic hydrocarbons such as benzene, toluene and xylene; aliphatic hydrocarbons such as hexane and heptane; cyclohexane , Alicyclic hydrocarbons such as bicyclo-2,2,1-heptane, ethers such as tetrahydrofuran, diethyl ether and the like can be used, but aromatic hydrocarbons are preferably used. The amount of the solvent used is 0.5 of all the monomers.
~ 5 PHR.

Block Copolymer The block copolymer produced in this manner is composed of a methacrylic acid alkyl ester (wherein the alkyl group has 1 to 12 carbon atoms).
3) a syndiotactic polymer block A based on
Acrylic acid alkyl ester (the carbon number of the alkyl group is 1
To A) containing a non-stereoregular polymer block (B) of formula A- (BA) _l- BA or A- (BA) _m- B [wherein l is 0 to 5; Integer, preferably 0 to 1, m is 1
-5, preferably 1-2 is shown. ] In the block copolymer represented by the following, the syndiotactic block A has a molecular weight of 1,000 to 700,000, preferably 10,000 to 100,000, and the non-stereoregular block B has a molecular weight of 1 2,000 to 700,000, preferably 10,000 to 100,000, and the total molecular weight of the block copolymer is 3,000 to 2,000,000.
It is a methacrylic block copolymer of 0, preferably 30,000 to 500,000.

The molecular weight distribution [Q value = weight average molecular weight (Mw) / number average molecular weight (Mn)] of each block is 1.0 to 1.5, preferably 1.5 to 1.5 for the syndiotactic polymethacrylic acid alkyl ester block A. Is 1.0 to 1.
It is more preferably 1.0 to 1.2, and in the non-stereoregular polyacrylic acid alkyl ester block B, 1.
It is 0 to 1.5, preferably 1.0 to 1.35, and more preferably 1.0 to 1.2. Furthermore, the Q value (Mw / Mn) of the entire block polymer is 1.0 to 1.6, preferably 1.0 to 1.5, and more preferably 1.0 to 1.35.

Since the molecular weight distribution is small as described above, a plastic molded product having excellent tensile strength is provided. Furthermore, the syndiotacticity (NMR method; triad rr) of the syndiotactic polymethacrylic acid alkyl ester block A is 60 to 100%, preferably 70 to 100.
%, 80 to 100% from the viewpoint of heat resistance.

The proportion of the syndiotactic block A in the copolymer is from 10 to 95% by weight, preferably from 20 to 90% by weight, and when the amount is less than 10% by weight, the tensile strength of the obtained molded product is extremely low. The thermoplastic elastomer (hardness (JISA) is about 20 to 99, compression set is about 10 to 90%, and tensile strength at break is 20 to 7).
00 kg / cm ² and elongation at tensile break of 30 to 1,0
It is about 00%. ) Is not exhibited.

This block copolymer is excellent in heat resistance because the polymethacrylic acid alkyl ester block A is highly syndiotactic. The tensile strength is large because the molecular weight distribution (Mw / Mn) is narrow. Further, the polyacrylic acid alkyl ester block B has non-stereoregularity, and at least one polyacrylic acid alkyl ester block B in the molecule of the block copolymer has a high syndiotactic polymethacrylic acid ester block A on both sides thereof. As a result, the block copolymer having a large amount of the block A portion has high impact resistance and the block copolymer having a small amount of the block A portion exhibits thermoplastic elastomer-like properties.

This means that in consideration of the fact that the binary block copolymer A-B does not exhibit thermoplastic elastomeric properties, or that only a molded product having poor impact resistance can be obtained. The block copolymer of the present invention containing at least a part of the skeleton is epoch-making. The block copolymer of the present invention makes use of the above-mentioned characteristics, and is in the form of a film, a sheet, a molded product, etc., food packaging, building parts, automobile interior / exterior parts, home electric appliance parts, kanban, name plates, daily use. It can be used for miscellaneous goods.

[0029]

【Example】

Example 1 In a flask having an inner volume of 500 ml replaced with argon,
300 ml of toluene dried and distilled over sodium, and 0.76 g of bispentamethylcyclopentadienyl samarium methyl-THF complex (C _P2 SMeme (THF))
A solution of (1.5 mmol) in 3.8 ml of toluene was added.

Stir until the solution is homogenous and mix at 0 ° C for the first time.
Methyl methacrylate (MMA) 7 as the second monomer
5 g (75 mmol) was added, and the mixture was stirred at 0 ° C for 10 minutes. When unreacted MMA in the system at this time was measured by gas chromatography (GC), only a trace amount of MMA was detected, and the conversion rate of methyl methacrylate was 99% or more. Also, withdraw 10 ml from the system and use 10 ml of methanol.
Polymer deposited by pouring into 0 ml (homopoly MMA)
Was centrifuged, dried under reduced pressure, dissolved in chloroform and measured by gel permeation chromatography (GPC). The number average molecular weight (Mn) was 4, 50.
0, molecular weight distribution (weight average molecular weight / number average molecular weight ratio: M
w / Mn) was 1.06. Furthermore, this homo PMM
When A was analyzed by NMR, the syndiotacticity of triad (rr) was 85.4%.

The original polymerization system was subsequently followed by n-butyl acrylate (n-BA) 19.2 as the second monomer.
g (150 mmol) was added, and stirring was continued at 0 ° C. for another 10 minutes. As a result of GC analysis, unreacted n-BA at this time was a trace amount, and the conversion rate of n-BA was 99% or more. In addition, according to the above-mentioned method, when GPC analysis is performed,
Single peak, Mn = 13,000, Mw / M
n = 1.20, and by NMR analysis, the composition was such that the constitutional unit of methyl methacrylate was 28% by weight, and acrylic acid n-
Since the constitutional unit of butyl is 72%, almost 100% of this polymer has a syndiotacticity of 85.4% in the poly MMA block portion, and the poly n-BA block portion has non-stereoregular MMA-n-. It is a BA binary block copolymer.

After the polymerization of n-butyl acrylate, subsequently, 7.5 g (75 mmol) of methyl methacrylate (MMA) as a third monomer was added to this polymerization system to give 0.
Stir at 20 ° C. for 20 minutes. At this time, the amount of unreacted MMA was a trace amount, and the conversion rate of MMA was 99% or more. After pouring the whole solution into 300 ml of methanol to deactivate the initiator, toluene and methanol were distilled off with an evaporator, the obtained polymer was dissolved in 200 ml of chloroform, and 400 ml of hexane was slowly added to the solution for precipitation. The polymer was recovered and dried under reduced pressure. Yield 13.
5 g (39.5%).

This polymer has a nearly single peak in GPC analysis, Mn = 93,000, Mw / Mn = 1.
18, the monomer composition was 68% by weight of MMA and the amount of n-BA was 32% by weight from NMR. Therefore, the syndiotacticity of the poly MMA block portion was 85.4% and the poly n-BA block portion had non-stereoregularity. MMA-BA-M
It is a ternary block copolymer of MA. The'H-NMR chart and GPC chart of the ternary block copolymer are shown in FIGS. 1 and 2, respectively.

On the other hand, from the filtrate, the same MMA-n-BA binary block copolymer 2 as before adding the third monomer was used.
Since 0.1 (58.8%) g was recovered, the composition of the above ternary block copolymer was MMA (13% by weight)-
It is n-BA (32% by weight) -MMA (55% by weight). The ternary block copolymer thus obtained was molded into a test piece with a microminiature injection molding machine (Minimax: trade name), and the Izod impact strength (non-notch) was measured.
kg · cm / cm ² and flexural modulus is 14,000
It was kg / cm ² . The tensile strength at break is 620k.
It was g / cm ² . The ternary block copolymer was analyzed by a differential scanning calorimeter (DSC).
Two Tg's, Tg (glass transition point) 125 ° C based on A block and Tg-51 ° C based on poly n-BA block.
Was observed.

Comparative Example 1 The amount of C _p2 SMeme (THF) was changed to 0.15 g, and 15 g (150 m) of MMA was used as the first monomer.
mol) instead of the first and second polymerization times of 1 hour, and the third polymerization is not performed,
The same method as in Example 1 was repeated until the Mn was 91,000.
0, MMA with Mw / Mn of 1.19 (68% by weight)
-N-BA (32% by weight) binary block copolymer, 3
3.8 g (yield 99%) was obtained.

The Izod impact strength (non-notch) of this binary block copolymer is 18 kg · cm / cm ² ,
The flexural modulus was 13,700 kg / cm ² and the tensile strength at break was 480 kg / cm ² . The reason why the Izod impact strength is significantly lower than that of Example 1 is that Example 1 is a ternary block copolymer, whereas the polymer of this Comparative Example is a binary block copolymer.

Example 2 In Example 1, the amount of C _p2 SMeme (THF) was adjusted to 0.
38 g, the first MMA polymerization time was 20 minutes, the second monomer n-BA amount was 48 g, the second polymerization time was 30 minutes, and the third monomer MMA amount was 5 minutes.
Example 1 was repeated except that the third polymerization time was changed to 1 hour and the Mn was 113,000 and Mw / M was changed.
n is 1.19 and the composition is MMA (9% by weight) -n-
BA (79% by weight) -MMA (12% by weight), and the syndiotacticity of the poly MMA block portion is 83.
45% (yield: 74%) of a ternary block copolymer having a non-stereoregular poly n-BA block portion of 2% was obtained. Since this copolymer has a large proportion of the copolymer of poly-n-BA blocks, it exhibits thermoplastic elastomer-like properties. Table 1 shows the physical properties.

Comparative Example 2 In Example 1, the amount of C _p2 SMeme (THF) was adjusted to 0.
24g, 1st MMA polymerization time to 30 minutes, 2nd
The same procedure as in Example 1 was repeated except that the third monomer n-BA was changed to 30 g, the second polymerization time was changed to 30 minutes, and the third polymerization was not performed, and Mn was 115,000 and M was 15,000.
37 g (yield 99%) of a binary block copolymer having w / Mn of 1.18 and a composition of MMA (20% by weight) -n-BA (80% by weight) was obtained. The properties of this binary copolymer are shown in Table 1.

[0039]

[Table 1]

As is clear from Table 1, since the polymer of Comparative Example 2 was a binary block copolymer, the hardness was almost the same as that of the ternary block copolymer of Example 2, and the tensile rupture was observed. It has a small point strength, a large compression set, a small elongation at tensile break, and has almost no thermoplastic elastomer characteristics. The ternary block copolymer of Example 2 shows remarkable thermoplastic elastomeric properties.

[0041]

EFFECT OF THE INVENTION A block copolymer having at least one structure in which a highly syndiotactic polymethacrylate ester polymer block is bonded to both ends of a polyacrylate ester polymer block molecule. Is a polymer having excellent heat resistance and impact resistance or thermoplastic elastomer properties.

[Brief description of drawings]

FIG. 1 is an'H-NMR chart of the ternary block copolymer obtained in Example 1.

FIG. 2 is a GPC chart of the ternary block copolymer obtained in Example 1.

Claims (3)

[Claims] 1. Non-stereoregularity of a syndiotactic polymer block A based on a methacrylic acid alkyl ester (wherein the alkyl group has 1 to 8 carbon atoms) and an acrylic acid alkyl ester (wherein the alkyl group has 1 to 8 carbon atoms). Formula A- (BA) _l- B-A or A- (BA) _m- B containing a polymer block (B) [In formula, 1 is an integer of 0-5, m is 1-5. Indicates an integer. ] The block copolymer represented by the following formula, wherein the molecular weight of block A is 1,000 to 700,000, and block B is
Has a molecular weight of 1,000 to 700,000, and the entire block copolymer has a molecular weight of 3,000 to 2,000,0.
A methacrylic block copolymer characterized in that it is 00. 2. The ratio (Mw / M) of the weight average molecular weight (Mw) and the number average molecular weight (Mn) of block A and block B.
The block copolymer according to claim 1, wherein each of n) is 1.0 to 1.5. 3. An organic rare earth metal complex as an initiator,
First, the methacrylic acid alkyl ester is polymerized at a temperature of 100 ° C. to + 100 ° C. until the conversion rate becomes 90% or more, and then the acrylic acid alkyl ester and the methacrylic acid alkyl ester are alternately alternated once or more, and the respective conversion rates are increased. Content of 90% or more is added and polymerized to produce a syndiotactic polymer block A based on methacrylic acid alkyl ester (alkyl group has 1 to 3 carbon atoms)
And a formula A- (BA) _l- BA or A- (BA) containing a non-stereoregular polymer block (B) of an acrylic acid alkyl ester (wherein the alkyl group has 1 to 8 carbon atoms). ) in _m -B [wherein, l represents an integer of 0 to 5, m is an integer of 1 to 5. ] The block copolymer represented by the following formula, wherein the molecular weight of block A is 1,000 to 700,000, and block B is
Has a molecular weight of 1,000 to 700,000, and the entire block copolymer has a molecular weight of 3,000 to 2,000,0.
A method for producing a block copolymer, comprising producing a methacrylic block copolymer of No. 00.