JP2002256156A - Polymer modifier and its production method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a polymer modifier which uses a low-molecular weight polymer having a narrow molecular distribution formed by radical polymerization with the use of a vinyl monomer and has no problem of the migration in the surface of a molded article. SOLUTION: A method for producing a polymer modifier comprises subjecting a vinyl monomer such as a styrenic monomer and a (meth)acrylate monomer to living radical polymerization in the presence of a transition metal and its ligand with the use of a polymerization initiator to form a low-molecular weight polymer having a glass transition temperature of -70 to 150 deg.C, a number average molecular weight of 500-15,000, and furthermore a molecular weight distribution of 1.0-2.5, and using this polymer as the effective component.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a polymer modifier comprising a low molecular weight polymer of various vinyl monomers such as styrene and (meth) acrylate.

[0002]

2. Description of the Related Art Low molecular weight polymers have higher reactivity than high molecular weight polymers due to their low molecular weight.
It has the feature of good compatibility with polymers. However, the synthesis methods are extremely diverse, such as how to regulate the molecular weight distribution and the terminal functional groups, and how to introduce specific functional groups, and there are many problems.
Most oligomers are unattractive because they are mixtures of molecules that differ not only in molecular weight, but sometimes in chemical structure.

[0003] Specifically, when a low molecular weight polymer having a wide molecular weight distribution containing a large amount of dimers or trimers is used as a polymer modifier, the dimer or trimer is formed on the surface of a polymer molded article. There are phenomena such as segregation of the trimer and bleeding and migration, which have a problem of adversely affecting the molded product surface.

[0004] By the way, Szwarc [N
atature 178, 1169 (1965); A
m. Chem. Soc. 78, 2656 (1956)]
The discovery of living anionic polymerization of polystyrene by the authors suggests that living polymerization is one of the methods suitable for controlling molecular weight and structure. In the anionic polymerization, unlike in the case of the cationic polymerization, the carbanion is stable, and in a sufficiently purified system, termination and transfer reaction hardly occur, and living polymerization is possible. However, there are few kinds of polymerizable monomers, and it is difficult to polymerize monomers having a functional group. This is due to the extremely high nucleophilicity of the terminal carbanion of the living polymer to be produced, for example, a highly reactive functional group such as a hydroxyl group, an amino group, or a carbonyl group having an active hydrogen, or a general functional group. But coexistence is difficult.

On the other hand, radical polymerization is the most widely used polymerization method in industry, and requires a wide variety of polymerizable monomers, easy handling of the reaction system, and a reduction in the production cost based thereon. It is considered that it is widely used. However, it has been difficult to obtain a low molecular weight polymer having a controlled molecular weight by radical polymerization because it is difficult to select the amount of a polymerization initiator and to control the heat of polymerization. Therefore, it is strongly required to refine the polymerization reaction by converting and controlling the growth terminal in radical polymerization, and a method for living polymerization of a monomer species that cannot be synthesized by ionic polymerization is desired.

[0006]

SUMMARY OF THE INVENTION In view of such circumstances, the present invention provides a low molecular weight polymer having a narrow molecular weight distribution by radical polymerization using various vinyl monomers such as styrene and (meth) acrylate. An object of the present invention is to obtain a polymer modifier free from the above-mentioned problems such as migration by generating a polymer and using the polymer as an active ingredient.

[0007]

Means for Solving the Problems The inventors of the present invention have conducted intensive studies to achieve the above object, and as a result, have found that vinyl monomers can be subjected to living radical polymerization using specific polymerization activators and polymerization initiators. According to the method, in the absence of a solvent or in the presence of a small amount of a solvent, without causing problems such as control of the heat of polymerization, a low molecular weight polymer having a narrow molecular weight distribution can be easily produced, and by using this as an active ingredient, The inventors have found that a polymer modifier free from the above-mentioned problems such as migration can be obtained, and have completed the present invention.

That is, according to the present invention, the glass transition temperature is-
70-150 ° C, number average molecular weight of 500-15,000
0, a polymer modifier characterized by comprising a low molecular weight polymer of a vinyl monomer having a molecular weight distribution of 1.0 to 2.5 as an active ingredient, in particular, the low molecular weight polymer has a molecular chain The present invention relates to the polymer modifier having the above constitution having at least one hydroxyl group or epoxy group at a terminal.

Further, the present invention provides a living radical polymerization of a vinyl monomer using a polymerization initiator in the presence of a transition metal and a ligand thereof to obtain a glass transition temperature of -70 to 150.
, A low molecular weight polymer having a number average molecular weight of 500 to 15,000 and a molecular weight distribution of 1.0 to 2.5, and using this as an active ingredient, a method for producing a polymer modifier. In particular, the present invention relates to a method for producing a polymer modifier having the above constitution, wherein the combination of the transition metal and the ligand is a Cu ^{+ 1} -bipyridine complex.

[0010]

The living radical polymerization method is described in, for example, (1) a report by Patten et al., "Radical
Polymerization Yielding Polymers with Mw / Mn 〜 1.0
5 by Homogeneous Atom Transfer Radical Polymerizat
ion ”Polymer Preprinted, pp 575-6, No37 (March 199
6), (2) Report by Matyjasewski et al., “Controlled
/ LivingRadical Polymerization. Halogen Atom Trans
fer Radical Polymerization Promoted by a Cu (I) / Cu
(II) Redox Process ”Macromolecules 1995,28,7901-10
(October 15,1995), (3) Same PCT / US96 / 0330
2, International Publication No. WO96 / 30421 (Oc
tober 3, 1996), (4) Report by M. Sawamoto et al., “Ruthen
ium-mediated Living Radical polymerization of Meth
yl Methacrylate "Macromolecules, 1996, 29, 1070.

The present inventors have focused on this living radical polymerization method, using a transition metal and its ligand as an activator, and in the presence of these, using a polymerization initiator to form various vinyl compounds. It has been found that a low molecular weight polymer having a narrow molecular weight distribution can be easily produced by subjecting a system monomer to living radical polymerization.

The transition metals include Cu, Ru, Fe, R
There are h, V and Ni, which are usually used from halides (chlorides, bromides, etc.) of these metals. The ligand is a ligand which coordinates with a transition metal as a center to form a complex, and a bipyridine derivative, a mercaptan derivative, a trifluorate derivative and the like are preferably used. Among combinations of transition metals and their ligands, C
The u ^{+ 1} -bipyridine complex is most preferred in terms of polymerization stability and polymerization rate.

The polymerization initiator is preferably an ester or styrene derivative containing a halogen at the α-position, particularly preferably a 2-bromo (or chloro) propionic acid derivative or a 1-phenyl chloride (or bromide) derivative. Used. Specifically, methyl 2-bromo (or chloro) propionate, 2-bromo (or chloro)
Ethyl propionate, 2-bromo (or chloro) -2
Methyl-methylpropionate, ethyl 2-bromo (or chloro) -2-methylpropionate, 1-phenylethyl chloride (or bromide) and the like.

The vinyl monomer may be any one as long as the polymer has a glass transition temperature of -70 to 150 ° C., and the type thereof is not particularly limited, and various types can be used. Specifically, styrene-based monomers such as styrene, α-methylstyrene, 2,4-dimethylstyrene, and 4-methoxystyrene as monomers for providing a polymer having a glass transition temperature of 20 ° C. or higher; Non-styrene monomers such as bornyl acrylate and dicyclopentanyl acrylate can be used.

Further, as a monomer for providing a polymer having a glass transition temperature of room temperature or lower, a monomer represented by the general formula: CH ₂ ＝ CR ¹ C
OOR ² (where R ¹ is a hydrogen atom or a methyl group, R ²
Is an alkyl group having 2 to 14 carbon atoms). In particular, n-butyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, and isooctyl (meth) can be used. C4 to C4 such as acrylate and isononyl (meth) acrylate
A (meth) acrylate having 12 alkyl groups is preferably used. As other vinyl monomers, maleic anhydride, maleic acid or a monoalkyl ester thereof, maleimide monomers, nitrile group-containing monomers such as acrylonitrile, and the like can also be used.

In the present invention, a homopolymer may be produced by selectively using only one of the above-mentioned vinyl monomers, or a copolymer may be produced by using a combination of two or more thereof. May be generated. When producing a copolymer,
Two or more monomers may be simultaneously subjected to living radical polymerization to form a random copolymer, or two or more monomers may be sequentially subjected to living radical polymerization to form a block copolymer. Is also good. When a block copolymer is formed, new functions such as the development of a microphase-separated structure and the role of a compatibilizer for two or more base polymers to improve the compatibility between the two polymers Can be expressed.

In the living radical polymerization, the polymerization initiator is usually used in an amount of 0.01 to 5 based on the vinyl monomer.
It is used in a mole% ratio. The amount of the transition metal used may be in the form of a halide or the like.
It is usually used at a ratio of 0.01 to 1 mol per mol. Further, the ligand is usually used in a ratio of 1 to 3 mol per 1 mol of the above-mentioned transition metal (form such as halide). When the polymerization initiator and the activator are used in such a ratio, good results can be obtained in the reactivity of living radical polymerization, the molecular weight of the produced polymer, and the like.

Such a living radical polymerization can proceed without a solvent or may proceed in the presence of a solvent such as butyl acetate, toluene, or xylene.
When a solvent is used, it is preferable to use a small amount so that the concentration of the solvent after the completion of the polymerization becomes 50% by weight or less in order to prevent a decrease in the polymerization rate. Even with no solvent or a small amount of solvent, there is no problem with respect to the control of the heat of polymerization, etc. Rather, the reduction of the solvent can provide favorable results in terms of economy and environmental measures. In addition, the polymerization conditions depend on the final molecular weight and the polymerization temperature at a polymerization temperature of 50 to 130 ° C. from the viewpoint of the polymerization rate and the deactivation of the catalyst, but the polymerization time is about 1 to 24 hours. I just need.

As described above, the low molecular weight polymer thus produced is composed of a homopolymer, a random copolymer or a block copolymer, and has a glass transition temperature of-.
70 to 150 ° C, number average molecular weight of 500 to 15,
000, preferably 1,000 to 10,000, and a molecular weight distribution (weight average molecular weight / number average molecular weight) of 1.0 to 2.5. Since it has such a narrow molecular weight distribution, there is an advantage that no problem such as migration occurs when used as a polymer modifier.

The above number average molecular weight is a value determined in terms of polystyrene by GPC (gel permeation chromatography). It is known that the number average molecular weight [Mn] of the produced polymer is given by Mn (calculated value) = [(molecular weight of monomer) × (molar ratio of monomer)] / (molar ratio of polymerization initiator). Have been. Therefore, theoretically, the number average molecular weight of the polymer can be intentionally controlled by adjusting the charging ratio of the vinyl monomer and the polymerization initiator.

When the number average molecular weight and the glass transition temperature are out of the above ranges, the use as a polymer modifier becomes inferior. In particular, when the number average molecular weight exceeds 15,000, the compatibility with the base polymer is reduced. When the ratio is less than 500, problems such as deterioration of the surface properties of a polymer molded product containing the same tend to occur.

In the present invention, a polymer having at least one hydroxyl group or epoxy group at a molecular chain terminal can be produced as the low molecular weight polymer. Such low molecular weight polymers include those having a hydroxyl group or an epoxy group in the molecule as a polymerization initiator, and those having a hydroxyl group or an epoxy group in the molecule as one kind of a vinyl monomer in the late stage of polymerization. Can be easily produced by adding or combining these. In particular,
By the above combination, a telechelic type low molecular weight polymer having the above functional groups at both molecular chain terminals can be produced.

When a polymerization initiator having a hydroxyl group or an epoxy group in the molecule is used, the above-mentioned functional group can be introduced into the starting terminal of the polymer molecular chain. Such a polymerization initiator is an ester-based or styrene-based derivative containing a halogen at the α-position and having the above functional group in its molecule, as long as it does not hinder the progress of living radical polymerization. , Can be used.

Specifically, examples of the polymerization initiator having a hydroxyl group in the molecule include 2-hydroxyethyl 2-bromo (or chloro) propionate and 2-bromo (or chloro) propionate.
4-hydroxybutyl propionate, 2-hydroxyethyl 2-bromo (or chloro) -2-methylpropionate, 4-hydroxybutyl 2-bromo (or chloro) -2-methylpropionate and the like.

The polymerization initiator having an epoxy group in the molecule includes glycidyl 2-bromo (or chloro) propionate, glycidyl 2-bromo (or chloro) -2-methylpropionate, 2-bromo (or chloro) ) 3,4-epoxycyclohexylmethyl propionate, 3,4-epoxycyclohexylmethyl 2-bromo (or chloro) -2-methylpropionate, and the like.

When a monomer having a hydroxyl group or an epoxy group in the molecule is used and added at the latter stage of the polymerization, the above-mentioned functional group can be introduced into the terminal end of the polymer molecular chain. The monomer having a hydroxyl group in the molecule is represented by the general formula: CH ₂ ＣC
R ³ COOR ⁴ (wherein, R ³ is a hydrogen atom or a methyl group, and R ⁴ is a C 2-6 having at least one hydroxyl group.
Hydroxyalkyl (meth) acrylate represented by the following formula: Specifically, 2-
Examples include hydroxyethyl (meth) acrylate, 3-hydroxypropyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, and 6-hydroxyhexyl (meth) acrylate.

The monomer having an epoxy group in the molecule is represented by the general formula: CH ₂ ＣＲCR ⁵ COOR ⁶ (wherein
R ⁵ is a hydrogen atom or a methyl group, R ⁶ is an alkyl group having 2 to 6 carbon atoms and having at least one epoxy group)
The epoxy group-containing (meth) acrylate represented by the following formula is used. Specifically, glycidyl (meth) acrylic
Methyl glycidyl (meth) acrylate, 3,4-
Epoxycyclohexylmethyl (meth) acrylate,
6-methyl-3,4-epoxycyclohexylmethyl (meth) acrylate and the like.

The low molecular weight polymer of the present invention thus obtained can be used for various uses as a polymer modifier depending on its glass transition temperature and the like. For example, a low molecular weight polymer having a glass transition temperature of 30 to 150 ° C. can be used as a tackifier for imparting tackiness by being blended with a base polymer of a pressure sensitive adhesive. In this case, the base polymer may be a rubber-based material such as natural rubber, synthetic rubber, synthetic isoprene rubber, styrene-butadiene copolymer rubber, or (meth) such as poly (meth) acrylate copolymer.
An acrylic material is used. These base polymers, particularly (meth) acrylic polymers, may be those synthesized by living radical polymerization or those synthesized by ordinary radical polymerization.

Further, a low molecular weight polymer having a glass transition temperature of -70 to 30 ° C. is mixed with a pressure-sensitive adhesive using a rubber-based polymer to increase the fluidity at low temperatures and to improve the tackiness. Can be used as In addition, it can be used as a leveling agent for paints and films for the purpose of enhancing fluidity. Further, such a low molecular weight polymer and the low molecular weight polymer having a glass transition temperature of 30 to 150 ° C. are added together to the pressure-sensitive adhesive so as to serve as both a tackifier and a softener. Can also.

Further, the low molecular weight polymer of the present invention can be used as an impact resistance improver which is blended with various thermoplastic resins or thermosetting resins to impart high impact resistance to these resins. Further, it can be used as a processability improver, a compatibilizer, and the like. In addition, low-molecular-weight polymers having at least one hydroxyl group or epoxy group at the molecular chain end react with the base polymer by heat, ultraviolet rays, etc., and thus can be used as a reactive polymer modifier. it can. In this use, it can be used in combination with a commercially available known crosslinking agent.

Further, the low molecular weight polymer of the present invention is synthesized using a living radical polymerization method, and therefore has a feature that it does not inhibit the radical reaction itself. Therefore, this low-molecular-weight polymer is added to a monomer for forming a base polymer, and the resulting polymer is subjected to various radical polymerizations such as solution polymerization, ultraviolet polymerization, and emulsion polymerization. It is also possible to obtain a polymer composition in which a molecular weight polymer is mixed and integrated. In this case, since a part of the base polymer is predicted to be grafted to the low-molecular-weight polymer, more favorable results can be obtained in the compatibility between the base polymer and the low-molecular-weight polymer.

[0032]

The present invention will now be described more specifically with reference to examples. In the following examples, most of the production raw materials used were commercially available raw materials, but commercially available ethyl 2-bromoisobutyrate (hereinafter referred to as 2-IL) was used as the polymerization initiator.
E) and α, α'-azobisisobutyronitrile (hereinafter referred to as AIBN), 2-hydroxyethyl 2-bromopropionate (hereinafter referred to as 2-H2PN), synthesized by the following method, 3,4-Epoxycyclohexylmethyl-bromo-2-methylpropionate (hereinafter referred to as 2-MPE) was used.

<Synthesis of 2-H2PN> 4.1 g (20 mmol) of dicyclohexylcarbodiimide, 5 g (81 mmol) of anhydrous ethylene glycol and 1 ml (12 mmol) of pyridine were placed in a reaction vessel, and 14 ml of acetone and 2-ml of 2-pyridine were added thereto. 2.5 g (16.7 mmol) of bromopropionic acid were added while cooling in an ice bath to suppress the exothermic reaction. After reacting for 16 hours, the precipitate was filtered off, 20 ml of ethyl acetate and 15 ml of saturated saline were added, and the mixture was shaken well. After standing for a while, the upper ethyl acetate layer was diluted with dilute hydrochloric acid.
The mixture was washed three times with 15 ml of saturated saline, and dried over anhydrous magnesium sulfate. After removing magnesium sulfate, ethyl acetate was distilled off under reduced pressure to obtain a crude product. The crude product thus obtained is subjected to silica gel chromatography (developing solvent: ethyl acetate / hexane =
1/1 mixed solvent) to give the desired product, 2-H2P
N was obtained. The yield was 1.5 g (46% by weight).

<Synthesis of 2-MPE> A reaction vessel was charged with 41.7 g (326 mmol) of 3,4-epoxycyclohexylmethyl alcohol, 50 ml (359 mmol) of triethylamine, 10 ml (124 mmol) of pyridine and 350 ml of acetone. To this were added 150 ml of acetone and 75 g (326 mmol) of 2-bromo-2-methylpropionic acid bromide while cooling with an ice bath to suppress the exothermic reaction. After reacting for 16 hours, the precipitate was filtered off, and acetone was distilled off under reduced pressure to obtain a crude product. The crude product thus obtained was purified by silica gel chromatography (developing solvent: acetone / hexane = 2/1 mixed solvent) to obtain 2-MPE, which was the target product. The yield was 38 g (42% by weight).

Example 1 Mechanical stirrer, nitrogen inlet, cooling pipe and rubber
50 g of styrene in a four-necked flask equipped with a septum
(478 mmol), and 1.872 g (12 mmol) of 2,2'-bipyridine was added thereto, and the atmosphere in the system was replaced with nitrogen. To this, copper bromide 0.715 g (5
), The reaction system was heated to 90 ° C., and 1,950 mg (10 mmol) of 2-ILE was added as a polymerization initiator to start polymerization. Under a nitrogen stream without adding a solvent,
Polymerization was performed at 90 ° C. for 8 hours. The polymer thus obtained was diluted to about 20% by weight with ethyl acetate, and the catalyst was removed by filtration. Finally, the ethyl acetate was distilled off, and the mixture was heated under reduced pressure (6.
0 ° C.) to obtain a low molecular weight polymer (1).

Example 2 A low molecular weight polymer was prepared in the same manner as in Example 1 except that the amount of styrene was changed to 100 g (956 mmol).
(2) was obtained.

Example 3 Mechanical stirrer, nitrogen inlet, cooling pipe and rubber
50 g of styrene in a four-necked flask equipped with a septum
(478 mmol), and 1.872 g (12 mmol) of 2,2'-bipyridine was added thereto, and the atmosphere in the system was replaced with nitrogen. To this, 0.715 g of copper bromide (5
), The reaction system was heated to 90 ° C, and 2,110 mg (10 mmol) of 2-H2PN was added as a polymerization initiator to start polymerization.
Polymerization was carried out at 90 ° C. for 8 hours. After confirming that the conversion was 80% by weight or more, 1.72 g (10 mmol) of 6-hydroxyhexyl acrylate was added to the polymerization system, and 1
Polymerization was carried out for 6 hours. The polymer thus obtained was diluted to about 20% by weight with ethyl acetate, and the catalyst was removed by filtration. Finally, the ethyl acetate is distilled off and heated under reduced pressure (60 ° C).
The low molecular weight polymer having a hydroxyl group at both ends of the molecule (3)
I got

Examples 4 to 13 The same procedure as in Example 1 or 3 was used except that the types and amounts of the vinyl monomer, the polymerization initiator and the functional group-containing monomer were changed as shown in Table 1. A low molecular weight polymer having or not having a hydroxyl group or an epoxy group at both molecular ends (4)
~ (13) was obtained. In each polymerization, the amount of copper bromide used was 0.5 times the molar amount of the polymerization initiator, and the amount of 2,2'-bipyridine was 1.2 times the molar amount.

In Table 1, "St" is styrene and "I"
“BXA” is isobornyl acrylate, “FEA” is phenoxyethyl acrylate, “EA” is ethyl acrylate, “BA” is n-butyl acrylate, “6-H
“HA” is 6-hydroxyhexyl acrylate, “3,
"4-ECMA" is 3,4-epoxycyclohexylmethyl acrylate. The numerical values in parentheses in Table 1 indicate the number of moles (mmol) of each raw material component.
It is shown.

[0040]

Comparative Example 1 In a flask equipped with a stirrer and a condenser, 100 g (780 mmol) of n-butyl acrylate was added with toluene 4
Dissolved in 100 g, and AI was added thereto as a polymerization initiator.
0.1 g of BN and 2 g of 2-mercaptoethanol as a chain transfer agent were added, and the reaction system was heated to 60 ° C. under a nitrogen gas stream to carry out polymerization. Thus, the low molecular weight polymer
(14) was produced.

The glass transition temperatures of the low molecular weight polymers (1) to (14) obtained in Examples 1 to 13 and Comparative Example 1 were examined by DSC (differential scanning calorimetry). Was as shown in FIG. The results of measurement of the number average molecular weight [Mn], the weight average molecular weight [Mw] and the degree of polymer dispersion [Mw / Mn] are as shown in Table 3. The molecular weight was measured by the GPC method described in the text.

[0043]

[0044]

As is clear from the results of Tables 2 and 3, each of the low molecular weight polymers of Examples 1 to 13 of the present invention synthesized by living radical polymerization has a glass transition temperature of -70 to 150 ° C. And the number average molecular weight is 500 to 15.0.
00 and the molecular weight distribution is 1.0 to 2.5.
And the characteristic that the molecular weight distribution width is narrow, the advantage that when this is used as a polymer modifier, problems such as bleeding and migration on the surface of the polymer molded article do not occur as in the past. have.

Actually, each of the low molecular weight polymers of Examples 1 to 13 was blended with a (meth) acrylic polymer obtained by a usual radical polymerization method, and the resulting mixture was coated on a support and subjected to a crosslinking treatment. When the pressure-sensitive adhesive sheets were prepared, all of them exhibited excellent pressure-sensitive adhesive properties with high adhesive force and high cohesive force without causing the above problems. On the other hand, when the low molecular weight polymer of Comparative Example 1 was used, it was found that the above-mentioned problems were likely to occur, and that the cohesive force was greatly reduced and the adhesive strength was also reduced. In addition, it was found that when each of the low-molecular-weight polymers of Examples 1 to 13 was blended with a commercially available polystyrene resin to form a film, a film with good elongation was obtained.

[0047]

As described above, in the present invention, a low molecular weight polymer having a narrow molecular weight distribution is produced by subjecting a vinyl monomer to living radical polymerization using a specific activator and polymerization initiator. By using this as an active ingredient of the polymer modifier, a special effect is provided in that a polymer modifier can be provided in which problems such as migration of the surface of a molded article as in the past can be avoided. .

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Tetsuo Inoue 1-2-1, Shimohozumi, Ibaraki-shi, Osaka Nitto Denko Corporation (72) Inventor Tomoko Doi 1-1-2 Shimohozumi, Ibaraki-shi, Osaka F-term in Nitto Denko Corporation (reference) 4J002 AC011 AC061 AC081 BG041 BG042 BG051 BG102 BH022 FD202 4J015 CA15 4J100 AJ09P AK32P AL03P AL04P AL36P AM02P AM43P BA03H BC54H CA27 CA31 FA03

Claims (4)

[Claims] 1. A glass transition temperature of -70 to 150 ° C., a number average molecular weight of 500 to 15,000, and a molecular weight distribution of 1.
A polymer modifier comprising, as an active ingredient, a low molecular weight polymer of a vinyl monomer having a ratio of 0 to 2.5. 2. The polymer modifier according to claim 1, wherein the low molecular weight polymer has at least one hydroxyl group or epoxy group at a molecular chain terminal. 3. A vinyl monomer is subjected to living radical polymerization using a polymerization initiator in the presence of a transition metal and its ligand, to have a glass transition temperature of -70 to 150 ° C. and a number average molecular weight of 500. ~ 15,000, molecular weight distribution 1.0 ~ 2.
5. A method for producing a polymer modifier, comprising producing a low-molecular-weight polymer of No. 5 and using the low-molecular-weight polymer as an active ingredient. 4. The combination of transition metal and ligand Cu ⁺¹
The method for producing a polymer modifier according to claim 3, which is a bipyridine complex.