JP7516347B2 - Method for producing vinyl polymer - Google Patents

Description

The present invention relates to a method for living radical polymerization of vinyl monomers.

Activators Regenerated by Electron Transfer Atom Transfer Radical Polymerization (ARGET ATRP) has been discovered, which is characterized by reacting a highly oxidized transition metal complex with a reducing agent to perform a catalytic cycle (Patent Document 1).

Using these polymerization methods, it has been possible to progress the polymerization reaction to a high conversion rate in a short time by using extremely small amounts of copper and polyamine, and further using a base and a reducing agent in combination, and to obtain a polymer with a narrow molecular weight distribution (Patent Document 2). It has also been reported that, in a similar recipe, the use of methanol as a solvent allows the polymerization of (meth)acrylic esters with 8 to 22 carbon atoms in the ester group to be controlled (Patent Document 3).

WO2005/087819 WO2012/020545 JP 2016-153464 A

In Patent Documents 1 to 3, there was a tendency for an induction period to occur during which polymerization did not start even when a reducing agent was added, and it was sometimes difficult to control the polymerization (e.g., control of the polymerization rate and/or heat generated by polymerization) by dropping a reducing agent.

One embodiment of the present invention has been developed in consideration of the above-mentioned problems, and its purpose is to provide a new method for producing vinyl polymers that can eliminate or shorten the induction period.

As a result of extensive research conducted by the inventors to solve the above problems, it was discovered that the induction period can be eliminated or shortened by using a highly oxidized metal compound other than copper in combination with a copper complex, which led to the completion of the present invention.

That is, the method for producing a vinyl polymer according to one embodiment of the present invention comprises carrying out living radical polymerization in the presence of the following (A) to (E):
Metallic copper or a copper compound (A),
Polyamine (B),
(C) a base other than a polyamine;
a reducing agent (D), and a highly oxidized non-copper metal compound (E).

In another embodiment of the present invention, a method for producing a vinyl polymer comprises carrying out living radical polymerization in the presence of the following (A), (B), (D), and (E), and using 0.8 to 1.5 times the number of moles of (B) relative to the total number of moles of transition metal atoms in (A) and transition metal atoms in (E):
Metallic copper or a copper compound (A),
Polyamine (B),
a reducing agent (D), and a highly oxidized non-copper metal compound (E).

In one embodiment of the present invention, a manufacturing method for synthesizing a vinyl polymer uses a copper complex in combination with a highly oxidizable metal species, making it possible to eliminate or shorten the induction period, thereby making it easier to control polymerization by dripping a reducing agent.

First, we will explain the living radical polymerization method in the manufacturing process of one embodiment of the present invention.

<Living radical polymerization>
One embodiment of the present invention relates to a method for the living radical polymerization of vinyl monomers catalyzed by a transition metal complex comprising (a) a transition metal or a transition metal compound, and (b) a ligand.

Currently, living radical polymerization using transition metal complexes as catalysts is considered to be two different interpretations: Atom Transfer Radical Polymerization (ATRP) (J. Am. Chem. Soc. 1995, 117, 5614, Macromolecules. 1995, 28, 1721) and Single Electron Transfer Polymerization (SET-LRP) (J. Am. Chem. Soc. 2006, 128, 14156, JPSChem 2007, 45, 1607). In ATRP, for example, in the case of copper complexes, a monovalent copper complex extracts a halogen from the polymer end to generate a radical, resulting in a divalent copper complex. The divalent copper complex returns a halogen to the radical at the polymerization end to become a monovalent copper complex. The living radical polymerization consisting of these equilibria is ATRP. On the other hand, in the case of a copper complex, zero-valent metallic copper or a copper complex extracts a halogen from the polymer end to generate a radical to become a monovalent copper complex. The divalent copper complex returns a halogen to the radical at the polymerization end to become a monovalent copper complex. The monovalent copper complex disproportionates to become zero-valent and divalent copper complexes. The living radical polymerization consisting of these equilibria is SET-LRP. The living radical polymerization of one embodiment of the present invention can also be interpreted as a living radical polymerization system of either ATRP or SET-LRP. In one embodiment of the present invention, ATRP and SET-LRP are not particularly distinguished from each other, and a living radical polymerization system using (a) a transition metal or transition metal compound and (b) a ligand as a catalyst is treated as the category of one embodiment of the present invention.

In addition, Activators Regenerated by Electron Transfer: ARGET (Macromolecules. 2006, 39, 39) has been reported as an improved formulation of ATRP, which uses a reducing agent to reduce highly oxidized transition metal complexes that cause polymerization delay or polymerization termination, thereby allowing the polymerization reaction to proceed quickly to a high reaction rate even under low catalyst conditions with a small amount of transition metal complexes. The living radical polymerization according to one embodiment of the present invention may be a living radical polymerization system of ARGET ATRP, which is an improved formulation of ATRP. That is, in one embodiment of the present invention, no particular distinction is made between ARGET ATRP, ATRP, and SET-LRP, and a living radical polymerization system using (a) a transition metal or transition metal compound and (b) a ligand as a catalyst is treated as the category of one embodiment of the present invention.

<<First and Second Embodiments>>
The present invention includes at least a "first embodiment" and a "second embodiment" described below.

[First embodiment]
A method for producing a vinyl polymer, comprising carrying out living radical polymerization in the presence of the following (A) to (E):
Metallic copper or a copper compound (A),
Polyamine (B),
(C) a base other than a polyamine;
a reducing agent (D), and a highly oxidized non-copper metal compound (E).

[Second embodiment]
A method for producing a vinyl polymer, comprising carrying out living radical polymerization in the presence of the following (A), (B), (D) and (E), and using 0.8 to 1.5 times the molar amount of (B) relative to the total molar amount of transition metal atoms in (A) and transition metal atoms in (E):
Metallic copper or a copper compound (A),
Polyamine (B),
a reducing agent (D), and a highly oxidized non-copper metal compound (E).

The first and second embodiments are described in detail below.

[1] First embodiment Since the first embodiment of the present invention has the above-mentioned configuration, it is possible to eliminate or shorten the induction period, and as a result, it has an advantage that polymerization control by addition of a reducing agent (D) becomes easy.

<Metallic copper or copper compound (A)>
Metallic copper or copper compound (A) forms a copper complex together with a ligand. In one embodiment of the present invention, a polyamine (B) is used as the ligand. That is, in one embodiment of the present invention, metallic copper or copper compound (A) and polyamine (B) form a copper complex. It is not necessary that all of the metallic copper or copper compound (A) used forms a copper complex with polyamine (B).

The method for producing a vinyl polymer according to the first embodiment of the present invention is a method for performing living radical polymerization in the presence of at least metallic copper or a copper compound (A). This is intended to mean that at least either metallic copper or a copper compound needs to be present in the reaction system of the living radical polymerization in the method for producing a vinyl polymer according to the first embodiment of the present invention. This does not exclude an embodiment in which both metallic copper and a copper compound are present in the reaction system of the living radical polymerization in the method for producing a vinyl polymer according to the first embodiment of the present invention.

The first embodiment of the present invention involves carrying out living radical polymerization in the presence of at least metallic copper or a copper compound (A) and a polyamine (B), and can therefore be said to be a method for producing a vinyl polymer in which living radical polymerization is carried out in the presence of a copper complex.

That is, the first embodiment of the present invention may be configured as follows.
A method for producing a vinyl polymer, comprising carrying out living radical polymerization in the presence of metallic copper or a copper complex comprising a copper compound (A) and a polyamine (B), and the following (C) to (E):
(C) a base other than a polyamine;
a reducing agent (D), and a highly oxidized non-copper metal compound (E).

The first embodiment of the present invention may be configured as follows.
A method for producing a vinyl polymer, comprising carrying out living radical polymerization in the presence of metallic copper or a copper complex comprising a copper compound (A) and a polyamine (B), and the following (B) to (E):
Polyamine (B),
(C) a base other than a polyamine;
a reducing agent (D), and a highly oxidized non-copper metal compound (E).

The metallic copper in the copper compound (A) is copper in the form of powdered copper, copper foil, or the like.

Examples of the copper compound in metallic copper or copper compound (A) include, but are not limited to, copper chloride, bromide, iodide, cyanide, oxide, hydroxide, acetate, sulfate, and nitrate.

The copper atom can have a valence of 0, 1, or 2 depending on the electronic state. The valence of the copper atom in metallic copper or copper compound (A) is not limited.

If the amount of copper atoms can be reduced, it becomes easier to remove the copper atoms, and the amount of polyamine (B) will also decrease in accordance with the amount of transition metal (weight of copper atoms). Therefore, the weight of the copper atoms in metallic copper or copper compound (A) is preferably 5 to 50 ppm, more preferably 5 to 15 ppm, and particularly preferably 5 to 10 ppm, relative to the total weight of the vinyl monomers charged. However, if the weight of the copper atoms in metallic copper or copper compound (A) is less than 5 ppm relative to the total weight of the vinyl monomers charged, it is not preferable because it is necessary to carry out polymerization for an extremely long time in order to obtain a polymer with a narrow molecular weight distribution.

Since metallic copper and copper compounds are solids, it is difficult to charge metallic copper or copper compound (A) to the reaction system. Therefore, it is preferable to mix metallic copper or copper compound (A) with a solvent and polyamine (B) in advance and charge the reaction system in a solution state in which metallic copper or copper compound (A) is dissolved. In this respect, it is more preferable for the copper atom in metallic copper or copper compound (A) to be monovalent copper or divalent copper than zero-valent copper, and divalent copper than monovalent copper, because it is more easily dissolved in various solvents.

In this specification, the term "reaction system" refers to a system in which a living radical polymerization reaction is progressing, and may also be referred to as a "polymerization system." The terms "reaction system" and "polymerization system" are interchangeable.

<Polyamine (B)>
The polyamine (B) according to one embodiment of the present invention refers to a compound having two or more nitrogen atoms with electron pairs that can be coordinated to metal atoms.The polyamine according to one embodiment of the present invention is, for example, an aliphatic amine or an aromatic amine.The polyamine according to one embodiment of the present invention may be, for example, a pyridine polyamine, a pyrrole polyamine, an imine polyamine, or the like, which has a structure in which the electron pairs of the nitrogen atoms resonate.

Specific examples of the polyamine (B) used as the ligand are shown below, but the polyamine (B) is not limited to these.
Bidentate polyamines: 2,2-bipyridine, 4,4'-di-(5-nonyl)-2,2'-bipyridine, N-(n-propyl)pyridylmethanimine, N-(n-octyl)pyridylmethanimine Tridentate polyamines: N,N,N',N'',N''-pentamethyldiethylenetriamine, N-propyl-N,N-di(2-pyridylmethyl)amine Tetradentate polyamines: hexamethyltris(2-aminoethyl)amine, N,N-bis(2-dimethylaminoethyl)-N,N'-dimethylethylenediamine, 2,5,9,12-tetramethyl-2,5,9,12-tetraazatetradecane, 2,6,9,1 3-tetramethyl-2,6,9,13-tetraazatetradecane, 4,11-dimethyl-1,4,8,11-tetraazabicyclohexadecane, N',N''-dimethyl-N',N''-bis((pyridin-2-yl)methyl)ethane-1,2-diamine, tris[(2-pyridyl)methyl]amine, 2,5,8,12-tetramethyl-2,5,8,12-tetraazatetradecane Pentadentate polyamine: N,N,N',N'',N''',N'''',N''''-heptamethyltetraethylenetetramine Hexadentate polyamine: N,N,N',N'-tetrakis(2-pyridylmethyl)ethylenediamine.

As polyamine (B), polyamines other than those mentioned above, such as polyethyleneimine, can be mentioned.

In order to proceed with polymerization at a sufficient reaction rate and obtain a polymer with a narrow molecular weight distribution under low-concentration catalyst conditions in which the total weight of transition metal atoms is 50 ppm or less relative to the total weight of vinyl monomers charged, polyamine (B) represented by general formula (1) or general formula (4) is preferred.

（式中、Ｒ^１、Ｒ^２およびＲ^３は、それぞれ独立して、一般式（２）または一般式（３）を表す。

(In the formula, R ¹ , R ² and R ³ each independently represent general formula (2) or general formula (3).

（式中、Ｒ^４、Ｒ^５、Ｒ^６およびＲ^７は、それぞれ独立して、水素原子または炭素数１～３のアルキル基を表す。）

(In the formula, R ⁴ , R ⁵ , R ⁶ and R ⁷ each independently represent a hydrogen atom or an alkyl group having 1 to 3 carbon atoms.)

（式中、Ｒ^８、Ｒ^９、Ｒ^１０、Ｒ^１１およびＲ^１２は、それぞれ独立して、水素原子または炭素数１～３のアルキル基を表す。）

(In the formula, R ⁸ , R ⁹ , R ¹⁰ , R ¹¹ and R ¹² each independently represent a hydrogen atom or an alkyl group having 1 to 3 carbon atoms.)

（ｎは０～３を表す。式中、Ｒ^１８、Ｒ^１９、Ｒ^２０およびＲ^２１は、それぞれ独立して、水素原子または炭素数１～３のアルキル基を表す。Ｒ^１３、Ｒ^１４、Ｒ^１５、Ｒ^１６およびＲ^１７は、それぞれ独立して、一般式（２）または一般式（３）を表す。）。

(n represents 0 to 3. In the formula, R ¹⁸ , R ¹⁹ , R ²⁰ and R ²¹ each independently represent a hydrogen atom or an alkyl group having 1 to 3 carbon atoms. R ¹³ , R ¹⁴ , R ¹⁵ , R ¹⁶ and R ¹⁷ each independently represent general formula (2) or general formula (3).

These polyamines (B) may be used alone or in combination.

With polyamines other than those represented by general formula (1) or general formula (4), it is possible to obtain a polymer with a narrow molecular weight distribution when polymerized over a long period of time, but when polymerization is carried out over a short period of time, the molecular weight distribution of the polymer becomes broad. Therefore, polyamines represented by general formula (1) or general formula (4) are preferred over polyamines other than those represented by general formula (1) or general formula (4).

Among the many polyamines, the specific polyamine (B) represented by general formula (1) and general formula (4) has the limitation that it is difficult to obtain industrially.

The amount of polyamine (B) used is preferably 70 mmol% or less, more preferably 40 mmol% or less, and even more preferably 20 mmol% or less, based on the total amount of vinyl monomers (100 mol%). Also, the amount is preferably 150 mol% or less, more preferably 120 mol% or less, even more preferably 110 mol% or less, and particularly preferably 100 mol% or less, based on the total amount of copper atoms in metallic copper or copper compound (A) (100 mol%).

<Base other than polyamine (C)>
In one embodiment of the present invention, the base other than polyamine (C) refers to a basic compound other than the polyamine (B). The base other than polyamine (C) neutralizes the acid present or generated in the polymerization system and prevents the accumulation of the acid. The base other than polyamine (C) may be (a) a compound that meets the definition of a Bronsted base and has the property of accepting a proton, or (b) a compound that meets the definition of a Lewis base and has an unshared electron pair and can donate it to form a coordinate bond. Specific examples of the base other than polyamine (C) are shown below, but the base other than polyamine (C) is not limited to them. Examples of the base other than polyamine (C) include monoamine bases, polyamine bases, and inorganic bases as shown below.

Monoamine base: A monoamine base is a compound that has only one site per molecule that acts as a base as defined above, and includes, but is not limited to, the following examples: (a) primary amines such as methylamine, aniline, and lysine; (b) secondary amines such as dimethylamine and piperidine; (c) tertiary amines such as trimethylamine and triethylamine; (d) aromatics such as pyridine and pyrrole; and (e) ammonia.

Polyamine bases: Examples of polyamine bases include (a) diamines such as ethylenediamine and tetramethylethylenediamine, (b) triamines such as diethylenetriamine and pentamethyldiethylenetriamine, (c) tetramines such as triethylenetetramine, hexamethyltriethylenetetramine, and hexamethylenetetramine, (d) polyethyleneimines, etc.

Inorganic bases: Inorganic bases refer to elements or compounds of Groups 1 and 2 of the periodic table, and are exemplified below but are not limited thereto. Examples of inorganic bases include (a) elements of Groups 1 and 2 of the periodic table, such as lithium, sodium, and calcium, (b) compounds of Groups 1 and 2 of the periodic table, such as sodium methoxide, potassium ethoxide, methyllithium, sodium hydroxide, potassium hydroxide, potassium carbonate, sodium bicarbonate, ammonium bicarbonate, trisodium phosphate, disodium hydrogen phosphate, tripotassium phosphate, dipotassium hydrogen phosphate, sodium acetate, potassium acetate, sodium oxalate, potassium oxalate, sodium phenoxy, potassium phenoxy, sodium ascorbate, and potassium ascorbate, and (c) salts of weak acids and strong bases, such as ammonium hydroxide.

These bases (C) other than polyamines may be used alone or in combination of multiple types.

In addition, a base (C) other than a polyamine may be added directly to the reaction system or may be generated in the reaction system.

Since the base other than polyamine (C) is used to protect the polyamine (B) from the acid, it is preferable that the basicity of the base other than polyamine (C) is equal to or stronger than that of the polyamine (B). In other words, it is preferable that the base dissociation constant (pKb) of the base other than polyamine (C) is equal to or lower than the pKb of the polyamine (B).

The base (C) other than the polyamine may be added to the reaction system in its entirety at once before the start of the reaction, or may be added gradually during the reaction. However, it is preferable that the amount of the base (C) is always 100 mol % or more relative to the electrons transferred by the added reducing agent (D).

There is no particular limitation on the order in which the polyamine (B) and the base other than the polyamine (C) are added to the metallic copper or copper compound.

There is no particular restriction on the order in which the base other than polyamine (C) and the reducing agent (D) are added to metallic copper or copper compound (A). When a hydride reducing agent is used as the reducing agent (D), the polymerization rate decreases and the molecular weight distribution of the polymer widens when the reducing agent (D) and the base other than polyamine (C) are mixed with the transition metal atom in this order. Therefore, when a hydride reducing agent is used as the reducing agent (D), it is preferable to mix the base other than polyamine (C) and the reducing agent (D) in this order, or simultaneously with the transition metal atom (e.g., metallic copper or copper compound (A)). This is presumably because, when a hydride reducing agent is used as the reducing agent (D), hydrogen halide is generated when the reducing agent (D) reduces the transition metal atom (e.g., metallic copper or copper compound (A)), and the polyamine (B) becomes an ammonium salt. One embodiment of the present invention is not limited to such a presumption. On the other hand, when a base other than a hydride reducing agent is used as the reducing agent (D), since no acid is generated when the reducing agent (D) reduces the transition metal atom, the order of adding the base (C) other than a polyamine and the reducing agent (D) to the metallic copper or copper compound (A) is not limited. However, the term "simultaneous" as used herein means that they are mixed at approximately the same timing, and is not strictly defined.

Depending on the solubility of the base other than polyamine (C), the effect of the base other than polyamine (C) is reduced. Therefore, when using a base that is poorly soluble in the polymerization solvent as the base other than polyamine (C), it is preferable to dissolve the base other than polyamine (C) in a good solvent in advance and add the base other than polyamine (C) in the form of a solution to the reaction system. Note that the "good solvent" here refers to a solvent that has excellent solubility for the base other than polyamine (C).

Regarding the amount of base (C) other than polyamine, it is preferable that it is added in an excess amount relative to polyamine (B) in order to protect polyamine (B). In addition, when a hydride reducing agent is used as reducing agent (D), hydrogen halide is generated when the added reducing agent (D) reduces a transition metal atom (e.g., metallic copper or copper compound (A)). Therefore, the amount of base (C) other than polyamine is preferably always 100 mol% or more of base (C) other than polyamine relative to the electrons transferred by reducing agent (D), more preferably 150 mol% or more, more preferably 200 mol% or more, and even more preferably 300 mol% or more. When a monoamine or inorganic base is used as base (C) other than polyamine, extraction by vacuum devolatilization or oil-water separation is possible, so there is no restriction on using an excess amount of base (C) other than polyamine.

<Reducing Agent (D)>
In living radical polymerization catalyzed by a copper complex consisting of metallic copper or a copper compound (A) and a polyamine (B), it has been found that the activity is improved by using a reducing agent in combination, although an excess of ligand (e.g., polyamine (B)) is required (ARGET ATRP). It is believed that this ARGET ATRP improves activity by reducing and reducing the high-oxidized copper complex that is generated by coupling between radicals during polymerization and causes reaction delay and reaction termination. This ARGET ATRP makes it possible to reduce the copper complex, which is usually required in the amount of several hundred to several thousand ppm, to several tens to several hundred ppm. In one embodiment of the present invention, the reducing agent (D) also functions in the same way as ARGET ATRP.

Specific examples of the reducing agent (D) used in one embodiment of the present invention are given below, but the reducing agent (D) is not limited to these reducing agents. Examples of the reducing agent (D) include (a) a reducing agent that does not generate an acid when reducing a copper complex, and (b) a reducing agent (hydride reducing agent) that generates an acid when reducing a copper complex.

(Reducing agent that does not generate acid when reducing copper complex)
Examples of reducing agents that do not generate an acid when reducing a copper complex include metals, metal compounds, organotin compounds, phosphorus or phosphorus compounds, and sulfur or sulfur compounds, as exemplified below.

Specific examples of metals include: (a) alkali metals such as lithium, sodium, and potassium; (b) alkaline earth metals such as beryllium, magnesium, calcium, and barium; (c) aluminum; (d) typical metals such as zinc; (e) transition metals such as copper, nickel, ruthenium, and iron; etc. These metals may also be in the form of an alloy (amalgam) with mercury.

Examples of the metal compound include (a) salts of typical metals or transition metals, and salts with typical elements, and (b) complexes in which a typical metal or transition metal is coordinated with carbon monoxide, an olefin, a nitrogen-containing compound, an oxygen-containing compound, a phosphorus-containing compound, a sulfur-containing compound, or the like. Specific examples of metal compounds include: (a) compounds of metals and ammonia/amines, titanium trichloride, titanium alkoxides, chromium chloride, chromium sulfate, chromium acetate, tin chloride, zinc acetate, and zinc _hydroxide ; (b) carbonyl complexes such as Ni(CO) ₄ and _Co2CO8 ; (c) olefin complexes such as [Ni(cod) ₂ ], [ _RuCl2 (cod)], and [ _PtCl2 (cod)] (wherein cod represents cyclooctadiene); and (d) phosphine complexes such as [RhCl(P( _{C6H5 ) 3} ) ₃ ], [ _RuCl2 (P( _{C6H5 ) 3} ) ₂ ], and [ _PtCl2 (P( _{C6H5 ) 3} ) ₂ ].

Specific examples of organotin compounds include tin octoate, tin 2-ethylhexylate, dibutyltin diacetate, dibutyltin dilaurate, dibutyltin mercaptide, dibutyltin thiocarboxylate, dibutyltin dimaleate, and dioctyltin thiocarboxylate.

Specific examples of phosphorus or phosphorus compounds include phosphorus, trimethylphosphine, triethylphosphine, triphenylphosphine, trimethylphosphite, triethylphosphite, triphenylphosphine, hexamethylphosphorus triamide, hexaethylphosphorus triamide, etc.

Specific examples of sulfur or sulfur compounds include sulfur, Rongalites, hydrosulfites, and _thiourea dioxide. Rongalite is a formaldehyde derivative of a sulfoxylate salt, and is represented by _MSO2.CH2O (M represents Na or Zn). Specific examples of Rongalite include sodium formaldehyde sulfoxylate and zinc formaldehyde sulfoxylate. Hydrosulfite is a general term for sodium hyposulfite and formaldehyde derivatives of sodium hyposulfite.

(Reducing agent (hydride reducing agent) that generates acid when reducing copper complex)
Examples of reducing agents (hydride reducing agents) that generate an acid when reducing a copper complex include metal hydrides, silicon hydrides, boron hydrides, nitrogen hydrogen compounds, phosphorus or phosphorus compounds, sulfur or sulfur compounds, organic compounds exhibiting a reducing action, and hydrogen, as exemplified below.
Specific examples of metal hydrides include (a) sodium hydride; (b) germanium hydride; (c) tungsten hydride; (d) aluminum hydrides such as diisobutylaluminum hydride, lithium aluminum hydride, sodium aluminum hydride, sodium triethoxyaluminum hydride, and sodium bis(2-methoxyethoxy)aluminum hydride; and (e) organotin hydrides such as triphenyltin hydride, tri-n-butyltin hydride, diphenyltin hydride, di-n-butyltin hydride, triethyltin hydride, and trimethyltin hydride.
Specific examples of silicon hydrides include trichlorosilane, trimethylsilane, triethylsilane, diphenylsilane, phenylsilane, and polymethylhydrosiloxane.
Specific examples of boron hydrides include borane, diborane, sodium borohydride, sodium trimethoxyborohydride, sodium borohydride sulfide, sodium cyanide borohydride, lithium cyanide borohydride, lithium borohydride, lithium triethylborohydride, lithium tri-s-butylborohydride, lithium tri-t-butylborohydride, calcium borohydride, potassium borohydride, zinc borohydride, tetra-n-butylammonium borohydride, and the like.
Specific examples of the nitrogen-hydrogen compound include hydrazine and diimide.
Specific examples of phosphorus or phosphorus compounds include phosphine and diazaphospholene.
Specific examples of sulfur or sulfur compounds include hydrogen sulfide.
Specific examples of organic compounds exhibiting a reducing action include alcohols, aldehydes, phenols, and organic acid compounds. Examples of alcohols include methanol, ethanol, propanol, and isopropanol. Examples of aldehydes include formaldehyde, acetaldehyde, benzaldehyde, and formic acid. Examples of phenols include phenol, hydroquinone, dibutylhydroxytoluene, and tocopherol. Examples of organic acid compounds include citric acid, oxalic acid, ascorbic acid, ascorbate, and ascorbate ester.

Among them, hydride reducing agents that generate acid when copper complexes are reduced lead to a decrease in polymerization rate and a widening of the molecular weight distribution due to deterioration of polymerization control when a base other than polyamine (C) is not used in combination, so it is more effective to use a base other than polyamine (C) in combination. This is presumably because the generated acid converts the polyamine (B) that forms the transition metal complex into an ammonium salt, destroying the complex structure. One embodiment of the present invention is not limited to such a presumption.

The stronger the reducing power of the reducing agent (D), the faster the polymerization can proceed. Among the above-mentioned compounds, metals, organotin compounds, ascorbic acid, ascorbic acid esters, ascorbate salts, hydrazine, and boron hydrides have strong reducing power and are more preferable as the reducing agent (D). Therefore, the reducing agent (D) is preferably at least one reducing agent selected from the group consisting of organotin compounds, ascorbic acid, ascorbic acid esters, ascorbate salts, hydrazine, and boron hydrides.

In addition, from the viewpoint of industrialization, it is preferable that the reducing agent (D) is also removed from the polymer after polymerization. Therefore, the reducing agent (D) preferably includes (a) hydrazine, oxalic acid, etc., whose oxides are easily removed by volatilization, and (b) sodium hydride, sodium borohydride, hydrazine, citric acid, oxalic acid, ascorbic acid, ascorbate salts, ascorbate esters, etc., whose oxides are easily removed by oil-water separation.

Therefore, as the reducing agent (D), ascorbic acid, ascorbate salts, ascorbate esters, and hydrazine are more preferred, and among these, ascorbic acid, ascorbate salts, and ascorbate esters are particularly preferred.

These reducing agents (D) may be used alone or in combination of two or more.

The reducing agent (D) may be added directly to the reaction system, or may be generated within the reaction system. The latter includes electrolytic reduction. In electrolytic reduction, it is known that the electrons generated at the cathode exhibit a reducing effect immediately, or after being solvated once. In other words, a reducing agent (D) generated by electrolysis can also be used.

If the amount of reducing agent (D) added is too small, sufficient polymerization activity cannot be expected, which is undesirable, and if the amount is too large, it is undesirable because it becomes difficult to remove the reducing agent (D) from the obtained polymer. That is, the amount of reducing agent (D) added is preferably 10 to 100,000 ppm, more preferably 10 to 10,000 ppm, even more preferably 10 to 1,000 ppm, and particularly preferably 10 to 500 ppm, relative to the total amount of vinyl monomer charged.

In addition, when the reducing agent (D) is a solid at room temperature, it is preferable to add the reducing agent (D) to the reaction system as a solution in a good solvent, since this is more effective. Note that the term "good solvent" here refers to a solvent that has excellent solubility for the reducing agent (D).

As can be seen from the mechanism of ARGET ATRP, if an excessive amount of reducing agent (D) is added at once, there will be a shortage of divalent copper complex to control the radicals, and the molecular weight distribution will widen due to coupling, etc. Therefore, the reducing agent (D) is added little by little as the polymerization progresses, specifically, it is preferably added at 1 to 1000 mol%/hour relative to the copper complex (100 mol%), more preferably at 5 to 700 mol%/hour, and particularly preferably at 10 to 500 mol%/hour.

There is no particular restriction on the order in which the base (C) other than polyamines and the reducing agent (D) are added to the copper complex. When a hydride reducing agent is used as the reducing agent (D), the polymerization rate decreases and the molecular weight distribution of the polymer widens when the reducing agent (D) and the base (C) other than polyamines are mixed with the copper complex, so it is preferable to mix the base (C) other than polyamines and the reducing agent (D) in that order, or simultaneously. This is presumed to be because, when a hydride reducing agent is used as the reducing agent (D), hydrogen halide is generated when the reducing agent (D) reduces the copper atom, and the polyamine (B) becomes an ammonium salt. One embodiment of the present invention is not limited to such a presumption. On the other hand, when a base other than a hydride reducing agent is used as the reducing agent (D), an acid is not generated when the reducing agent (D) reduces the copper atom, so the order in which the base (C) other than polyamines and the reducing agent (D) are added to the copper complex is not limited. However, the term "simultaneous" here refers to mixing at approximately the same timing, and is not strict. In particular, when ascorbic acid is used as the reducing agent (D), the solubility of the reducing agent (D) and the base other than polyamine (C) in the organic solvent is improved by mixing the reducing agent (D) with the base other than polyamine (C) in advance, and the operability is improved. Therefore, in particular, when ascorbic acid is used as the reducing agent (D), it is preferable to add the base other than polyamine (C) and the reducing agent (D) to the reaction system at the same time.

<Highly oxidized metal compounds other than copper (E)>
In one embodiment of the present invention, the "highly oxidized metal compound other than copper (E)" refers to a metal compound that satisfies both of the following two conditions.

(a) It contains metal atoms other than copper, which can have multiple oxidation numbers. (b) The oxidation numbers of the metal atoms other than copper mentioned above are on the higher side.

The metal species of the highly oxidized non-copper metal compound (E) is not particularly limited as long as it is a metal that has multiple oxidation states at room temperature and normal pressure and shows a high oxidation number. For example, in the case of Fe, it is known that it can take the oxidation states of Fe(II) and Fe(III) at room temperature and normal pressure, so that highly oxidized Fe(III) corresponds to the highly oxidized non-copper metal compound (E). Similarly, highly oxidized transition metals such as Zn(IV), Mn(IV), Sn(VI), Cr(II), Co(III), Rh(II), Ru(III), Sc(III), Te(III), Bi(III), and Sb(III) can also be listed as the metal species of the highly oxidized non-copper metal compound (E). Examples of the metal compound (E) other than the highly oxidized copper include, but are not limited to, metal compounds of these metal species, such as chlorides, bromides, iodides, cyanides, oxides, hydroxides, acetates, sulfates, and nitrates. As the metal compound (E) other than the highly oxidized copper, among the above, a trivalent iron compound is preferable, and one or more selected from the group consisting of iron chloride (III), iron bromide (III), iron iodide (III), and iron trioxide (Fe ₂ O ₃ ) (III) are more preferable. This configuration has the advantage of being highly effective in shortening the induction period.

The amount of metal compound (E) other than highly oxidized copper is preferably such that the molar ratio of metallic copper or copper compound (A)/metal compound (E) other than highly oxidized copper is 0.9/0.1 to 0.2/0.8. This configuration has the advantage of being able to obtain a polymer with a narrow molecular weight distribution while having the effect of shortening the induction period.

Since the highly oxidized metal compound other than copper (E) is a solid, it is difficult to add it to the reaction system. Therefore, it is preferable to mix the highly oxidized metal compound other than copper (E) with a solvent in advance and add it to the reaction system in the form of a solution in which the highly oxidized metal compound other than copper (E) is dissolved.

It is preferable that the weight (amount used) of the metal compound (E) other than highly oxidized copper is within a certain molar ratio range with metallic copper or copper compound (A). If the amount of the metal compound (E) other than highly oxidized copper can be reduced, it becomes easier to remove the metal compound (E) other than highly oxidized copper. Therefore, the weight (amount used) of the metal compound (E) other than highly oxidized copper is preferably 1 to 200 ppm, more preferably 1 to 100 ppm, and particularly preferably 1 to 40 ppm, relative to the total weight of the vinyl monomer charged.

The weight (amount used) of the metal compound (E) other than highly oxidized copper is preferably 1 to 200 ppm, more preferably 1 to 100 ppm, and particularly preferably 1 to 40 ppm, based on the total weight of the vinyl monomer charged, converted into the weight of the metal atoms in the metal compound (E) other than highly oxidized copper.

The highly oxidized metal compound (E) other than copper reacts with the reducing agent (D) to generate a low-oxidized metal compound other than copper. It is presumed that this low-oxidized metal compound other than copper (a) reduces a copper complex consisting of metallic copper or copper compound (A) and polyamine (B), or (b) reacts directly with an initiator to generate radicals, thereby shortening the induction period that occurs in the reaction between the copper complex and the reducing agent (D). Therefore, it is preferable to add the reducing agent (D) to the reaction system after adding metallic copper or copper compound (A), polyamine (B), and highly oxidized metal compound other than copper (E) to the reaction system. In other words, it is preferable to mix metallic copper or copper compound (A), polyamine (B), and highly oxidized metal compound other than copper (E) and then add the reducing agent (D). Note that one embodiment of the present invention is not limited to such a presumption.

<Vinyl Monomer>
Examples of the vinyl monomer in one embodiment of the present invention include (meth)acrylic monomers, acrylamide monomers, styrene monomers, vinyl chloride monomers, vinyl carboxylate monomers, etc. Among these, (meth)acrylic monomers, acrylamide monomers, and styrene monomers are preferred, and (meth)acrylic monomers are particularly preferred.

In this specification, "(meth)acrylic" refers to "acrylic" and/or "methacrylic".

Examples of the (meth)acrylic monomer in one embodiment of the present invention include methyl (meth)acrylate, ethyl (meth)acrylate, n-propyl (meth)acrylate, isopropyl (meth)acrylate, n-butyl (meth)acrylate, isobutyl (meth)acrylate, tert-butyl (meth)acrylate, n-pentyl (meth)acrylate, n-hexyl (meth)acrylate, cyclohexyl (meth)acrylate, n-heptyl (meth)acrylate, n-octyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, nonyl (meth)acrylate, decyl (meth)acrylate, dodecyl (meth)acrylate, phenyl (meth)acrylate, toluyl (meth)acrylate, benzyl (meth)acrylate, 2-methoxyethyl (meth)acrylate, 3-methoxypropyl (meth)acrylate, 2-hydroxyethyl (meth)acrylate, and (meth)acrylic acid. Examples of the monomer include 2-hydroxypropyl acrylate, stearyl (meth)acrylate, glycidyl (meth)acrylate, 2-aminoethyl (meth)acrylate, γ-(methacryloyloxypropyl)trimethoxysilane, ethylene oxide adduct of (meth)acrylic acid, trifluoromethylmethyl (meth)acrylate, 2-trifluoromethylethyl (meth)acrylate, 2-perfluoroethylethyl (meth)acrylate, 2-perfluoroethyl-2-perfluorobutylethyl (meth)acrylate, 2-perfluoroethyl (meth)acrylate, perfluoromethyl (meth)acrylate, diperfluoromethylmethyl (meth)acrylate, 2-perfluoromethyl-2-perfluoroethylmethyl (meth)acrylate, 2-perfluorohexylethyl (meth)acrylate, 2-perfluorodecylethyl (meth)acrylate, and 2-perfluorohexadecylethyl (meth)acrylate. These monomers may be used alone or may be copolymerized with a plurality of monomers. If necessary, other monomers than the (meth)acrylic monomer may be copolymerized with the (meth)acrylic monomer. In one embodiment of the present invention, the (meth)acrylic polymer obtained when the (meth)acrylic monomer is used as the vinyl monomer preferably has 5% by weight or more, more preferably 50% by weight or more, and even more preferably 80% by weight or more of repeating units derived from the (meth)acrylic monomer in the total repeating units.

The vinyl polymer obtained in one embodiment of the present invention preferably has repeating units derived from vinyl monomers in an amount of 5% by weight or more of the total repeating units, more preferably 50% by weight or more, and even more preferably 80% by weight or more.

<Initiator>
In one embodiment of the present invention, an organic halide having a highly reactive carbon-halogen bond can be used as the polymerization initiator. Examples of the organic halide include a carbonyl compound having a halogen at the α-position, a compound having a halogen at the benzyl position, and a sulfonyl halide compound. Specific examples of organic halides 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 (wherein, in the above chemical formula, C ₆ H ₅ is a phenyl group, and X is chlorine, bromine, or iodine); R ³ -C(H)(X)-CO ₂ R ⁴ , R ³ -C(CH ₃ )(X)-CO ₂ R ⁴ , R ³ -C(H)(X)-C(O)R ⁴ , R ³ -C(CH ₃ )( ^X )-C(O)R ⁴ (wherein, R ³ and R ⁴ are hydrogen atoms or alkyl groups, aryl groups, or aralkyl groups having 1 to 20 carbon atoms, and X is chlorine, bromine, or iodine); -C ₆ H ₄ -SO ₂ X (wherein R ³ is a hydrogen atom or an alkyl group, an aryl group, or an aralkyl group having 1 to 20 carbon atoms, and X is a chlorine, bromine, or iodine atom); and the like.

Alternatively, an organic halide having two or more initiation points or a sulfonyl halide compound having two or more initiation points may be used as an initiator.

A characteristic of living radical polymerization is that the desired polymer molecular weight can be set by adjusting the ratio of the amount of monomer to the amount of initiator.

The molecular weight of the polymer can be set by the ratio of the amount of monomer to the amount of initiator. The lower the set molecular weight, the more difficult it is to control the amount of radicals produced, and the more likely it is that the molecular weight distribution will broaden. Even if the set molecular weight is high, the influence of side reactions (termination reactions and serial reactions) is large, and the molecular weight distribution will tend to broaden. For this reason, the amount of initiator is preferably 0.0001 to 10 mol% relative to the amount of monomer (100 mol%), and more preferably 0.001 to 20 mol%.

<Solvent>
Specific examples of the solvent in one embodiment of the present invention are given below, but when this living radical polymerization method is used, the solvent is not particularly limited.
Highly polar aprotic solvent: dimethylsulfoxide (DMSO), dimethylformamide (DMF), N,N-dimethylacetamide (DMAc), N-methylpyrrolidone, etc. Carbonate solvent: ethylene carbonate, propylene carbonate, etc. Alcohol solvent: methanol, ethanol, propanol, isopropanol, n-butyl alcohol, tert-butyl alcohol, etc. Nitrile solvent: acetonitrile, propionitrile, benzonitrile, etc. Ketone solvent: acetone, methyl ethyl ketone, methyl isobutyl ketone, etc. Ether solvent: diethyl ether, tetrahydrofuran, etc. Halogenated carbon solvent: methylene chloride, chloroform, etc. Ester solvent: ethyl acetate, butyl acetate, etc. Hydrocarbon solvent: pentane, hexane, cyclohexane, octane, decane, benzene, toluene, etc. Examples of the solvent in one embodiment of the present invention include ionic liquids and water. A supercritical fluid may be used as the solvent in one embodiment of the present invention.

The above solvents can be used alone or in combination of two or more.

In the living radical polymerization method, the chain transfer reaction to the solvent is a factor in the deterioration of polymerization control, but the polymerization control is also deteriorated by the precipitation of the reducing agent (D). Therefore, the amount of the solvent is preferably 0.5 to 60 parts by weight, more preferably 2 to 20 parts by weight, per 100 parts by weight of the total weight of the vinyl monomers charged.

Furthermore, it is more preferable that the metallic copper or copper compound (A), polyamine (B), base other than polyamine (C), reducing agent (D), metal compound other than highly oxidized copper (E), vinyl monomer and initiator are uniform in the reaction system in terms of reaction control, polymerization reaction rate, ease of charging and risk of scale-up. Therefore, it is preferable to select a solvent that dissolves them. For example, when ascorbic acid is used as the reducing agent (D), the solubility of the reducing agent (D) greatly affects the reducing power of the reducing agent (D), so that the solvent is preferably a solvent that can dissolve ascorbic acid, a salt of ascorbic acid or an ester of ascorbic acid, for example, (a) an alcohol-based solvent such as methanol, ethanol, propanol, isopropanol, n-butyl alcohol, tert-butyl alcohol, etc., (b) a highly polar aprotic solvent such as dimethyl sulfoxide (DMSO), dimethylformamide (DMF), N,N-dimethylacetamide (DMAc), N-methylpyrrolidone, etc., and (c) water. It is also useful to mix these solvents with other solvents to prepare mixed solvents, thereby improving the solubility of ascorbic acid, which is the reducing agent (D).

[2] Second embodiment Since the second embodiment of the present invention has the above-mentioned configuration, it is possible to eliminate or shorten the induction period, and as a result, it has an advantage that polymerization control by addition of a reducing agent (D) becomes easy.

<Metallic copper or copper compound (A)>
The metallic copper or copper compound (A) in the second embodiment is the same as that in the first embodiment.

<Polyamine (B)>
The polyamine (B) in the second embodiment is the same as that in the first embodiment. However, the polyamine (B) in the second embodiment also plays the role of the base (C) other than the polyamine in the first embodiment. The amount of polyamine (B) used in the second embodiment is as follows.

In the second embodiment, the amount of polyamine (B) used is preferably 80 to 150 mol%, more preferably 90 to 120 mol%, even more preferably 95 to 110 mol%, and particularly preferably 100 mol%, relative to the transition metal atoms (100 mol%) present in the polymerization system. In the second embodiment, it is preferable to add polyamine (B) to the polymerization system in multiple installments. The polyamine (B) added later (added after the second installment) is often intended to neutralize the acid present or generated in the polymerization system and prevent the accumulation of acid.

<Reducing Agent (D)>
The reducing agent (D) in the second embodiment is the same as that in the first embodiment.

<Highly oxidized metal compounds other than copper (E)>
In the second embodiment, the highly oxidized metal compound (E) other than copper is the same as that in the first embodiment.

<Vinyl Monomer>
The vinyl monomer in the second embodiment is the same as that in the first embodiment.

<Initiator>
The initiator in the second embodiment is the same as that in the first embodiment.

<Solvent>
The solvent in the second embodiment is the same as that in the first embodiment.

<Vinyl-based polymer obtained according to one embodiment of the present invention>
The number average molecular weight of the vinyl polymer obtained by the production method according to one embodiment of the present invention is not particularly limited, but is preferably in the range of 500 to 1,000,000, more preferably in the range of 1,000 to 500,000, even more preferably in the range of 3,000 to 300,000, and particularly preferably in the range of 5,000 to 300,000.

The molecular weight distribution of the vinyl polymer obtained by the production method according to one embodiment of the present invention, i.e., the ratio of the weight average molecular weight (Mn) to the number average molecular weight (Mw) measured by gel permeation chromatography, is preferably 1.1 to 1.8, more preferably 1.1 to 1.7, more preferably 1.1 to 1.5, and even more preferably 1.1 to 1.3. In the GPC measurement according to one embodiment of the present invention, chloroform is usually used as the mobile phase, and the measurement is performed in a polystyrene gel column, and the number average molecular weight and the like can be calculated in terms of polystyrene.

The conversion rate of the vinyl monomer, which is the monomer of the vinyl polymer obtained by the production method according to one embodiment of the present invention, i.e., the ratio of the number of moles of vinyl monomer remaining in the reaction system to the total number of moles of vinyl monomer charged ((total number of moles of vinyl monomer charged - number of moles of vinyl monomer remaining in the reaction system) / total number of moles of vinyl monomer charged x 100) (%) is not particularly limited, but is preferably 85% or more, preferably 90% or more, and more preferably 95% or more.

The polymerization time from the start of mixing metallic copper or copper compound (A), polyamine (B), base other than polyamine (C), reducing agent (D) and metal compound other than highly oxidized copper (E) for the vinyl polymer obtained by the manufacturing method according to the first embodiment of the present invention is not particularly limited, but is preferably 360 minutes or less, preferably 300 minutes or less, and more preferably 240 minutes or less.

The polymerization time from the start of mixing metallic copper or copper compound (A), polyamine (B), reducing agent (D) and metal compound other than highly oxidized copper (E) for the vinyl polymer obtained by the manufacturing method according to the second embodiment of the present invention is not particularly limited, but is preferably 360 minutes or less, preferably 300 minutes or less, and more preferably 240 minutes or less.

The polymerization temperature is not limited, but if it is too low, the reaction rate may be slow, and if the temperature is too high, side reactions (serial reactions) are more likely to occur, so a temperature in the range of 0 to 100°C is preferable, 20 to 90°C is more preferable, and 40 to 70°C is even more preferable.

The polymerization atmosphere is not limited, but when the polymerization reaction is carried out in the presence of oxygen, the metallic copper or copper compound (A), the highly oxidized metal compound other than copper (E), and the compound reduced by the reducing agent (D) may be oxidized by oxygen, resulting in poor polymerization control. Therefore, it is preferable to carry out the polymerization reaction in an inert gas atmosphere, and it is more preferable to carry out the polymerization reaction in a nitrogen atmosphere in consideration of production costs, etc.

The vinyl polymer main chain obtained by the manufacturing method according to one embodiment of the present invention may be linear or branched.

The vinyl polymer obtained by the manufacturing method according to one embodiment of the present invention is preferably a (meth)acrylic polymer. This configuration has the advantage of easily obtaining a polymer with a narrow molecular weight distribution. In this specification, the term "(meth)acrylic polymer" refers to a polymer containing repeating units derived from a (meth)acrylic monomer. The vinyl polymer obtained by the manufacturing method according to one embodiment of the present invention preferably has repeating units derived from a (meth)acrylic monomer in an amount of 5% by weight or more of the total repeating units, more preferably 50% by weight or more, and even more preferably 80% by weight or more. This configuration has the advantage of obtaining a polymer with a narrow molecular weight distribution.

An embodiment of the present invention may have the following configuration:

[1] A method for producing a vinyl polymer, characterized by carrying out living radical polymerization in the presence of the following (A) to (E): metallic copper or a copper compound (A), a polyamine (B), a base other than a polyamine (C), a reducing agent (D), and a highly oxidized metal compound other than copper (E).

[2] A method for producing a vinyl polymer, comprising carrying out living radical polymerization in the presence of the following (A), (B), (D) and (E), and using 0.8 to 1.5 times the molar amount of (B) relative to the total molar amount of the transition metal atoms in (A) and the transition metal atoms in (E): metallic copper or a copper compound (A), a polyamine (B), a reducing agent (D), and a metal compound other than highly oxidized copper (E).

[3] The method for producing a vinyl polymer according to [1] or [2], wherein the vinyl polymer is a (meth)acrylic polymer.

[4] A method for producing a vinyl polymer described in any one of [1] to [3], wherein the metal compound (E) other than highly oxidized copper is a trivalent iron compound.

[5] The method for producing a vinyl polymer according to [4], wherein the trivalent iron compound is one or more compounds selected from the group consisting of iron chloride, iron bromide, iron iodide and diiron trioxide (Fe ₂ O ₃ ).

[6] A method for producing a vinyl polymer described in any one of [1] to [5], characterized in that the molar ratio of metallic copper or copper compound (A) to metal compound other than highly oxidized copper (E) is 0.9/0.1 to 0.2/0.8.

[7] A method for producing a vinyl polymer according to any one of [1] to [6], characterized in that the highly oxidized metal compound (E) other than copper is used in an amount of 1 to 40 ppm, calculated as the weight of metal atoms, relative to the total amount of the vinyl monomer charged.

[8] A method for producing a vinyl polymer according to any one of [1] to [7], characterized in that the metallic copper or copper compound (A), the polyamine (B), and the highly oxidized metal compound other than copper (E) are mixed, and then the reducing agent (D) is added.

[9] A method for producing a vinyl polymer described in any one of [1] to [8], characterized in that the reducing agent (D) is at least one reducing agent selected from the group consisting of organic tin compounds, ascorbic acid, ascorbic acid esters, ascorbate salts, hydrazine, and boron hydrides.

An embodiment of the present invention may have the following configuration:

[1] A method for producing a (meth)acrylic polymer, in which a copper complex (A) is used as a catalyst to polymerize a (meth)acrylic monomer in a living radical polymerization process, the method being characterized in that a polydentate amine (B), a base other than a polydentate amine (C), a reducing agent (D), and a highly oxidized metal compound other than copper (E) are contained in the reaction system relative to the (meth)acrylic monomer.

[2] A method for producing a (meth)acrylic polymer according to [1], wherein the highly oxidized metal compound (E) is a trivalent iron compound.

[3] A method for producing a (meth)acrylic polymer according to [2], characterized in that the trivalent iron compound (E) is one or more compounds selected from the group consisting of iron chloride, iron bromide, iron iodide and iron trioxide (Fe2O3).

[4] A method for producing a (meth)acrylic polymer described in any one of [1] to [3], characterized in that the molar ratio of copper complex/highly oxidized metal compound other than copper (E) is 0.9/0.1 to 0.2/0.8.

[5] A method for producing a (meth)acrylic polymer according to any one of [1] to [4], characterized in that the metal atom of a metal compound (E) other than highly oxidized copper is contained in an amount of 1 to 40 ppm by weight relative to the total amount of (meth)acrylic monomer charged.

[6] A method for producing a (meth)acrylic polymer according to any one of [1] to [5], characterized in that a reducing agent (C) is subsequently mixed with the copper complex and the highly oxidized metal compound other than copper (E).

[7] A (meth)acrylic polymer according to any one of [1] to [6], characterized in that the reducing agent (D) is at least one selected from the group consisting of organic tin compounds, ascorbic acid, ascorbic acid esters, ascorbate salts, hydrazine, and boron hydrides.

Specific examples of the present invention are shown below, but the present invention is not limited to the following examples. In the following examples and comparative examples, "parts" and "ppm" represent "parts by weight" and "parts per million by weight", respectively. "Number average molecular weight" and "molecular weight distribution (ratio of weight average molecular weight to number average molecular weight)" were calculated by standard polystyrene conversion method using gel permeation chromatography (GPC). However, a GPC column filled with polystyrene crosslinked gel (Shodex GPC K-804; Showa Denko K.K.) was used, and chloroform was used as the GPC solvent.

In addition, the reagents used in the following examples and comparative examples were obtained from mass producers with an eye toward industrialization, and were used in the reactions without any purification or other processing.

Example 1
In a reaction vessel, 40 parts of 2-methoxyethyl acrylate, 12 parts of methanol (MeOH), 3.33 parts of ethyl 2-bromobutyrate, and 0.41 parts of triethylamine were charged, and the charged raw materials were stirred under a nitrogen stream at 40° C. Next, a solution obtained by dissolving 0.015 parts of copper bromide (II) (CuBr ₂ ) (Cu amount relative to the total weight of the reaction system excluding the ascorbic acid solution = 35 ppm) and 0.005 parts of iron (III) bromide (Fe amount relative to the total weight of the reaction system excluding the ascorbic acid solution = 7 ppm) in 8 parts of methanol, and 0.020 parts of hexamethyltris(2-aminoethyl)amine (Me ₆ TREN) (equivalent amount (103.2 mol%) relative to the total molar amount (100 mol%) of Cu and Fe) were separately prepared, and these were added to the reaction system, and the raw materials in the reaction system were mixed. Further, 0.015 parts of ascorbic acid and 0.017 parts of triethylamine were prepared with 3.0 parts of methanol, and the resulting ascorbic acid solution was started to be dropped into the reaction system. After the start of the dropwise addition of the ascorbic acid solution, the reaction solution was heated within 1 minute, and polymerization was started. During the polymerization, the reaction solution was continued to be heated and stirred so that the temperature of the reaction solution was 40 to 60°C. 30 minutes after the start of the dropwise addition of the ascorbic acid solution, the reaction rate (polymerization conversion rate) of 2-methoxyethyl acrylate was 27 mol%, the number average molecular weight was 1,200, and the molecular weight distribution was 1.30. At this point (i.e., 30 minutes after the start of polymerization), 60 parts of 2-methoxyethyl acrylate was added dropwise to the reaction system over 2 hours. Thereafter, the reaction solution was continued to be heated and stirred so that the temperature of the reaction solution was 40°C to 60°C while the ascorbic acid solution was added dropwise to the reaction system. 240 minutes after the start of the dropwise addition of the ascorbic acid solution, the reaction rate of 2-methoxyethyl acrylate was 81 mol%, the number average molecular weight was 4,800, the molecular weight distribution was 1.16, and the total amount of ascorbic acid dropped was 32 ppm based on the total weight of the reaction system excluding the ascorbic acid solution.

In Example 1, (a) the amount of copper atoms (Cu) in copper bromide, which is the metallic copper or copper compound (A), relative to the total amount of 2-methoxyethyl acrylate, which is the vinyl monomer, was 42.7 ppm, (b) the amount of iron atoms (Fe) in iron (III) bromide, which is the highly oxidized metal compound other than copper (E), relative to the total amount of 2-methoxyethyl acrylate, which is the vinyl monomer, was 9.4 ppm, and (c) the amount of hexamethyltris(2-aminoethyl)amine (Me ₆ (d) the amount of substance of triethylamine (a base other than a polyamine (C)) relative to the electrons transferred by ascorbic acid (a reducing agent (D)) was always 100 mol %, (e) the addition rate of the ascorbic acid solution to the copper complex (100 mol %) was 8.3 mol %/hour, (f) the molar ratio of metallic copper or copper compound (A)/highly oxidized metal compound other than copper (E) was 0.8/0.2, and (g) the total amount of ascorbic acid dropped relative to the total amount of 2-methoxyethyl acrylate, which is a vinyl monomer, was 26 ppm.

Example 2
A reaction vessel was charged with 40 parts of 2-methoxyethyl acrylate, 12 parts of methanol (MeOH), 3.33 parts of ethyl 2-bromobutyrate, and 0.41 parts of triethylamine, and the charged raw materials were stirred at 40° C. under a nitrogen stream. Next, 0.017 parts of copper bromide (II) (CuBr ₂ ) (Cu amount relative to the total weight of the reaction system excluding the ascorbic acid solution = 39 ppm) and 0.0007 parts of iron trioxide (Fe ₂ O ₃ ) (III) (Fe amount relative to the total weight of the reaction system excluding the ascorbic acid solution = 4 ppm) were dissolved in 8 parts of methanol, and 0.020 parts of hexamethyltris(2-aminoethyl)amine (Me ₆ TREN) (equivalent amount (101.2 mol%) to the total molar amount (100 mol%) of Cu and Fe) were separately prepared and added to the reaction system to mix the raw materials in the reaction system. Furthermore, 0.015 parts of ascorbic acid and 0.017 parts of triethylamine were prepared with 3.0 parts of methanol, and the resulting ascorbic acid solution was started to be dropped into the reaction system. When the amount of ascorbic acid added reached 8 ppm relative to the total weight of the reaction system excluding the ascorbic acid solution from the start of the dropwise addition of the ascorbic acid solution (20 minutes after the start of the dropwise addition of the ascorbic acid solution), the reaction solution generated heat and polymerization was initiated. During the polymerization, the reaction solution was continued to be heated and stirred so that the temperature of the reaction solution was 40 to 60°C. 60 minutes after the start of the dropwise addition of the ascorbic acid solution, the reaction rate (polymerization conversion rate) of 2-methoxyethyl acrylate was 24 mol%, the number average molecular weight was 1,200, and the molecular weight distribution was 1.30. At this point (i.e., 40 minutes after the start of the polymerization), 60 parts of 2-methoxyethyl acrylate was added dropwise to the reaction system over a period of 2 hours. Thereafter, the reaction solution was continued to be heated and stirred so that the temperature of the reaction solution was 40 to 60°C while the ascorbic acid solution was added dropwise to the reaction system. After 320 minutes from the start of the dropwise addition of the ascorbic acid solution, the reaction rate of 2-methoxyethyl acrylate was 95 mol%, the number average molecular weight was 5,200, the molecular weight distribution was 1.14, and the total amount of ascorbic acid dropped was 33 ppm based on the total weight of the reaction system excluding the ascorbic acid solution.

In Example 2, (a) the amount of copper atoms (Cu) in copper bromide, which is the metallic copper or copper compound (A), relative to the total amount of 2-methoxyethyl acrylate, which is the vinyl monomer, was 49 ppm, (b) the amount of iron atoms (Fe) in iron trioxide (III), which is the highly oxidized metal compound other than copper (E), relative to the total amount of 2-methoxyethyl acrylate, which is the vinyl monomer, was 4.9 ppm, and (c) the amount of hexamethyltris(2-aminoethyl)amine (Me ₆ (d) the amount of substance of triethylamine (a base other than a polyamine (C)) relative to the electrons transferred by ascorbic acid (a reducing agent (D)) was always 100 mol %, (e) the addition rate of the ascorbic acid solution to the copper complex (100 mol %) was 22.0 mol %/hour until the initiation of polymerization (i.e., until 20 minutes have elapsed since the initiation of dropwise addition of the ascorbic acid solution) and 4.6 mol %/hour after the initiation of polymerization, (f) the molar ratio of metallic copper or copper compound (A)/highly oxidized metal compound other than copper (E) was 0.9/0.1, and (g) the total amount of ascorbic acid added dropwise relative to the total amount of 2-methoxyethyl acrylate, which is a vinyl monomer, was 27 ppm.

(Comparative Example 1)
A reaction vessel was charged with 40 parts of 2-methoxyethyl acrylate, 12 parts of methanol (MeOH), 3.33 parts of ethyl 2-bromobutyrate, and 0.41 parts of triethylamine, and the charged raw materials were stirred under a nitrogen stream at 40° C. Next, a solution obtained by dissolving 0.019 parts of copper bromide (II) (CuBr ₂ ) (Cu amount relative to the total weight of the reaction system excluding the ascorbic acid solution=44 ppm) in 8 parts of methanol, and 0.020 parts of hexamethyltris(2-aminoethyl)amine (Me ₆ TREN) (equivalent amount (102.0 mol%) relative to the molar amount of Cu (100 mol%)) were separately prepared, and these were added to the reaction system, and the raw materials in the reaction system were mixed. Further, 0.015 parts of ascorbic acid and 0.017 parts of triethylamine were prepared in 3.0 parts of methanol, and the resulting ascorbic acid solution was added dropwise to the reaction system to initiate polymerization. When the amount of ascorbic acid reached 10 ppm relative to the total weight of the reaction system excluding the ascorbic acid solution (50 minutes after the start of the addition of the ascorbic acid solution), the reaction system solution generated heat and polymerization was initiated. During the polymerization, the reaction solution was heated and stirred so that the temperature of the reaction solution was 40 to 60°C. 95 minutes after the start of the addition of the ascorbic acid solution, the reaction rate (polymerization conversion rate) of 2-methoxyethyl acrylate was 21 mol%, the number average molecular weight was 1,600, and the molecular weight distribution was 1.30. At this point (i.e., 45 minutes after the start of polymerization), 60 parts of 2-methoxyethyl acrylate was added dropwise to the reaction system over a period of 2 hours. Thereafter, the reaction solution was continued to be heated and stirred while the ascorbic acid solution was added dropwise to the reaction system so that the temperature of the reaction solution was 40° C. to 60° C. After 395 minutes from the start of the dropwise addition of the ascorbic acid solution, the reaction rate of 2-methoxyethyl acrylate was 96 mol%, the number average molecular weight was 5,600, the molecular weight distribution was 1.08, and the total amount of ascorbic acid dropped was 52 ppm based on the total weight of the reaction system excluding the ascorbic acid solution. By this operation, a vinyl polymer was obtained.

In Comparative Example 1, (a) the amount of copper atoms (Cu) in the metallic copper or copper bromide, which is a copper compound, relative to the total amount of 2-methoxyethyl acrylate, which is a vinyl monomer, was 54.1 ppm, and (b) the amount of hexamethyltris(2-aminoethyl)amine (Me ₆ (c) the amount of substance of triethylamine (a base other than polyamine) relative to the electrons transferred by ascorbic acid (reducing agent) was always 100 mol %, (d) the addition rate of the ascorbic acid solution to the copper complex (100 mol %) was 9.9 mol %/hour until the initiation of polymerization (i.e., until 50 minutes have elapsed since the initiation of dropwise addition of the ascorbic acid solution) and 6.0 mol %/hour after the initiation of polymerization, and (e) the total amount of ascorbic acid added dropwise relative to the total amount of 2-methoxyethyl acrylate, which is a vinyl monomer, was 42 ppm.

(Comparative Example 2)
In a reaction vessel, 40 parts of 2-methoxyethyl acrylate, 12 parts of methanol (MeOH), 3.33 parts of ethyl 2-bromobutyrate, and 0.41 parts of triethylamine were charged, and the charged raw materials were stirred at 40°C under a nitrogen stream. Subsequently, a solution obtained by dissolving 0.025 parts of iron (III) bromide (Fe amount relative to the total weight of the reaction system excluding the ascorbic acid solution = 39 ppm) in 8 parts of methanol, and 0.020 parts of hexamethyltris(2-aminoethyl)amine (Me ₆ TREN) (equivalent amount (102.6 mol%) to the molar amount (100 mol%) of Fe) were separately prepared, and these were added to the reaction system, and the raw materials in the reaction system were mixed. Furthermore, 0.015 parts of ascorbic acid and 0.017 parts of triethylamine were prepared with 3.0 parts of methanol, and the resulting ascorbic acid solution was started to be dropped into the reaction system. Within 1 minute after the start of the dropwise addition of the ascorbic acid solution, the reaction solution was heated and polymerization was initiated. During the polymerization, the reaction solution was continued to be heated and stirred so that the temperature of the reaction solution was 40 to 60°C. 40 minutes after the start of the dropwise addition of the ascorbic acid solution, the reaction rate (polymerization conversion rate) of 2-methoxyethyl acrylate was 14 mol%, the number average molecular weight was 86,400, and the molecular weight distribution was 2.29. At this point (i.e., 40 minutes after the start of polymerization), 60 parts of 2-methoxyethyl acrylate was added dropwise to the reaction system over 2 hours. Thereafter, the reaction solution was continued to be heated and stirred so that the temperature of the reaction solution was 40 to 60°C while the ascorbic acid solution was added dropwise to the reaction system. 250 minutes after the start of the dropwise addition of the ascorbic acid solution, the reaction rate of 2-methoxyethyl acrylate was 91 mol%, the number average molecular weight was 86,370, the molecular weight distribution was 2.51, and the total amount of ascorbic acid dropped was 52 ppm based on the total weight of the reaction system excluding the ascorbic acid solution.

In Comparative Example 2, (a) the amount of iron atoms (Fe) in iron (III) bromide, which is a highly oxidized metal compound other than copper, relative to the total amount of 2-methoxyethyl acrylate, which is a vinyl monomer, was 47.2 ppm, (b) the amount of hexamethyltris(2-aminoethyl)amine (Me ₆ TREN) (polyamine) relative to the total amount of 2-methoxyethyl acrylate (100 mol%) was 11 mmol%, (c) the amount of triethylamine (a base other than polyamine) relative to the electrons transferred by ascorbic acid (reducing agent) was always 100 mol%, (d) the addition rate of the ascorbic acid solution relative to the copper complex (100 mol%) was 10.3 mol%/hour, and (e) the total amount of ascorbic acid dropped relative to the total amount of 2-methoxyethyl acrylate, which is a vinyl monomer, was 42 ppm.

Comparative Example 1 is a system (production method) in which metallic copper or a copper compound is used alone, that is, a system (production method) in which metallic copper or a copper compound is used but no metal compound other than highly oxidized copper is used. In the system of Comparative Example 1, there is a region (induction period) in which the polymerization reaction does not proceed even if ascorbic acid, which is a reducing agent, is added. This induction period ends when a predetermined amount of ascorbic acid is added, and the polymerization reaction starts. Depending on the various conditions such as the type and/or shape of the reaction vessel, the end time of the induction period, in other words, the time from the addition of ascorbic acid to the start of the polymerization reaction, varies slightly. Therefore, it is difficult to accurately determine the amount of ascorbic acid required to end the induction period. If the dripping speed of ascorbic acid is too fast immediately after the induction period and too much ascorbic acid is added, a sudden polymerization heat will occur and the reaction will not be controllable. If the dripping speed of ascorbic acid is slowed down to avoid the sudden heat generation, the induction period will be prolonged and productivity will drop significantly. Therefore, when no metal compound (E) other than highly oxidized copper was used as in Comparative Example 1, the presence of this induction period made it difficult to achieve both polymerization control, such as heat generation, and productivity.

In contrast to the system (production method) of Comparative Example 1 in which metallic copper or a copper compound is used alone, Examples 1 and 2 are systems (production methods) in which part of the copper (copper compound) is replaced with iron bromide (III) or iron trioxide (III), which is a highly oxidized metal compound (E) other than copper. Examples 1 and 2 are systems (production methods) in which copper bromide (II), which is metallic copper or a copper compound (A), and iron bromide (III) or iron trioxide (III), which is a highly oxidized metal compound (E) other than copper, are used. In both Examples 1 and 2, it can be seen that the amount of ascorbic acid (reducing agent (D)) required to terminate the induction period is less than that in Comparative Example 1. In particular, in Example 1, polymerization began almost simultaneously with the addition of ascorbic acid. In Examples 1 and 2, although an iron compound, which is a highly oxidized metal compound (E) other than copper, is used in combination with a copper compound, which is metallic copper or a copper compound (A), reaction control was maintained and the molecular weight distribution was 1.2 or less.

Comparative Example 2 is a system (production method) that does not use a copper complex, i.e., does not use metallic copper or a copper compound, but uses only iron (III) bromide, a highly oxidized metal compound other than copper. In the system of Comparative Example 2, as in Example 1, no induction period was observed, and polymerization began simultaneously with the addition of ascorbic acid. However, in the production method of Comparative Example 2, the molecular weight and molecular weight distribution of the obtained polymer were significantly broadened, and the reaction could not be controlled.

From the above results, it is evident that a method for polymerizing a vinyl polymer having high reaction controllability and capable of shortening the induction period has been achieved by using in combination a copper catalyst having high reaction controllability but an induction period and an iron catalyst having low reaction controllability but no induction period.

Claims (8)

A method for producing a vinyl polymer, comprising carrying out living radical polymerization of a vinyl monomer in the presence of the following (A), (B), (D) and (E), and using 0.8 to 1.5 times the molar amount of (B) relative to the total molar amount of the transition metal atoms in (A) and the transition metal atoms in (E):
Metallic copper or a copper compound (A),
Polyamine (B),
a reducing agent (D), and a highly oxidized non-copper metal compound (E);
Here, the highly oxidized metal compound (E) other than copper refers to a metal compound that satisfies both of the following two conditions:
(a) It contains metal atoms other than copper that can have multiple oxidation numbers. (b) The oxidation numbers of the metal atoms other than copper are the higher values ;
The highly oxidized metal compound other than copper (E) is a trivalent iron compound . The method for producing a vinyl polymer according to claim 1, wherein the living radical polymerization is further carried out in the presence of a base (C) other than a polyamine. The method for producing a vinyl polymer according to claim 1 or 2, wherein the vinyl polymer is a (meth)acrylic polymer. 2. The method for producing a vinyl polymer according to claim 1 , wherein the trivalent iron compound is at least one compound selected from the group consisting of iron chloride, iron bromide, iron iodide and diiron trioxide (Fe ₂ O ₃ ). The method for producing a vinyl polymer according to any one of claims 1 to 4 , characterized in that a molar ratio of the metallic copper or copper compound (A) to the highly oxidized metal compound other than copper (E) is 0.9/0.1 to 0.2/0.8. The method for producing a vinyl polymer according to any one of claims 1 to 5, characterized in that the highly oxidized metal compound other than copper (E) is used in an amount of 1 to 40 ppm in terms of the weight of metal atoms relative to the total amount of the vinyl monomers charged. The method for producing a vinyl polymer according to any one of claims 1 to 6, characterized in that the metallic copper or copper compound (A), the polyamine ( B ) and the highly oxidized metal compound other than copper (E) are mixed together, and then the reducing agent (D) is added. The method for producing a vinyl polymer according to any one of claims 1 to 7, wherein the reducing agent ( D ) is at least one reducing agent selected from the group consisting of organotin compounds, ascorbic acid, ascorbic acid esters, ascorbate salts, hydrazine, and boron hydrides.