Polymer production method, composition for radical polymerization, and radical polymerization controller

Abstract

A method for producing a polymer which includes a polymerization step in which controlled radical polymerization of a monomer (Y) is conducted in the presence of an organic compound (A) represented by formula (I) and a radical generator (B), the molar ratio of (B) to (A), B / A, being 0.5-20. According to the production method, a high-molecular-weight polymer having high safety can be synthesized with precise regulation of the molecular arrangement, terminal structure, etc. Furthermore, the production method is lowly toxic, is friendly to the environment, and is inexpensive. [In formula (I), R1 is an alkenyl or aryl group, R2 is a group represented by formula (II) or (III), and R1 and R2 may have been bonded to each other to form a ring.] [In formula (II), R3 is a hydrogen atom, a halogen atom, or an alkyl, aryl, alkenyl, alkoxy, amino, nitro, cyano, acetyl, trifluoromethyl, or hydroxyl group and * indicates a bond.] [In formula (III), R3 has the same meaning as in formula (II) and * indicates a bond.]

Description

[Technical Field]

[0001] The present invention relates to a method for producing a polymer, which includes a polymerization step of polymerizing a polymerizable monomer by controlled radical polymerization, and also to a composition for radical polymerization and a radical polymerization controller used in such a production method. [Background technology]

[0002] Polyvinyl alcohol resin is a crystalline, water-soluble polymer material. Taking advantage of its excellent water solubility and film-forming properties (strength, oil resistance, film-forming ability, oxygen gas barrier properties, etc.), it is widely used in emulsifiers, suspending agents, surfactants, fiber processing agents, various binders, paper processing agents, adhesives, films, etc. Conventional polyvinyl alcohols with different degrees of saponification and polymerization have been used depending on the application. Various modified polyvinyl alcohols have also been proposed, in which special functions are imparted by introducing functional groups into polyvinyl alcohol.

[0003] Polyvinyl alcohol is industrially produced by saponifying polyvinyl acetate, which is obtained by radical polymerization of vinyl acetate. In the radical polymerization of vinyl acetate, various side reactions such as chain transfer reactions and recombination termination reactions occur simultaneously during the polymerization, so it is generally considered difficult to precisely control the molecular arrangement and terminal structure of the resulting polyvinyl acetate (and polyvinyl alcohol).

[0004] In recent years, advances in so-called living radical polymerization technology have led to the development of several methods for controlling the radical polymerization of vinyl acetate. For example, a method has been proposed for obtaining polyvinyl acetate with a precisely controlled structure by conducting the radical polymerization of vinyl acetate in the presence of a radical polymerization initiator and a specific control agent. In this polymerization reaction, the growing radical end of the polyvinyl acetate molecular chain covalently bonds with the control agent to form a dormant species, and the polymerization proceeds while an equilibrium is formed between the dormant species and the radical species generated by its dissociation. This type of polymerization reaction is called controlled radical polymerization.

[0005] However, it has been difficult to obtain high-molecular-weight polyvinyl acetate using conventional controlled radical polymerization methods. This is thought to be because the radicals generated at the ends of head-to-head bonds (bonds between adjacent acetyl groups in vinyl acetate), which are formed with a certain probability during polymerization, are extremely thermally unstable, causing the equilibrium to shift significantly toward dormant species, preventing further polymerization reaction progress. On the other hand, if the polymerization temperature is increased to promote thermal dissociation of the dormant species, the reaction proceeds, but controllability deteriorates. Therefore, it has been extremely difficult to obtain high-molecular-weight polyvinyl acetate while maintaining controllability.

[0006] To address these challenges, a method has been proposed for synthesizing high-molecular-weight polyvinyl acetate with a controlled structure by controlled radical polymerization using an organic cobalt complex as a control agent. In this polymerization reaction, the growing radical end of the polyvinyl acetate molecular chain covalently bonds with the cobalt atom of the organic cobalt complex to form a dormant species, and polymerization proceeds while an equilibrium is formed between the dormant species and the radical species generated by its dissociation. For example, Non-Patent Document 1 reports the synthesis of polyvinyl acetate with a number-average molecular weight (Mn) of 99,000 and a molecular weight distribution (Mw / Mn) of 1.33 by polymerizing vinyl acetate in the presence of cobalt(II) acetylacetonate.

[0007] Patent Document 1 describes that polyvinyl alcohol obtained by controlled radical polymerization has a problem of being significantly discolored, but that polyvinyl alcohol with reduced discoloration can be obtained by contacting a polyvinyl acetate solution obtained by controlled radical polymerization using an organic cobalt complex as a control agent with an aqueous solution containing a water-soluble ligand, extracting and removing the cobalt complex, and then saponifying the resulting solution.

[0008] However, polymerization methods using such metal complexes have the drawback that it is difficult to completely remove the used complexes from the resulting polymer. Many transition metals are highly toxic, and the toxicity of transition metals remaining in molded articles using the resulting polymers can pose environmental problems, making it difficult to use molded articles containing transition metals in food packaging, biomedical materials, and other applications. The toxicity of unnecessary complexes or complexes removed from the polymer after the reaction can also pose environmental problems. Furthermore, complex removal requires the use of a large amount of extraction solution, which complicates the process and increases costs. Furthermore, metal complexes are typically expensive and require complex synthesis.

[0009] Living radical polymerization methods that do not require the use of metal complexes are also known. For example, methods using nitroxyl-, iodine-, or dithioester-based compounds are known. However, these methods require the introduction of special protecting groups into the growing polymer chain, which are extremely expensive. Another drawback is the need to conduct the polymerization reaction at high temperatures (e.g., 110°C or higher). Another drawback is the insufficient control of vinyl ester polymerization, making it difficult to obtain high-molecular-weight polymers. Another drawback is that the resulting polymers tend to have undesirable properties, such as coloration and odor. Furthermore, it is difficult to completely remove the compounds used from the product, and residual organic halogen compounds and organic sulfur compounds may pose health and environmental problems.

[0010] Cinnamic acid and its derivatives are widely found in nature and are commonly used industrially as food additives and flavorings. Although cinnamic acids have unsaturated double bonds, they are difficult to homopolymerize. However, it is known that radical polymerization of cinnamic acid monomers can proceed under limited conditions, such as copolymerization with fumaric acid diesters (Non-Patent Document 2, Patent Document 2). It is also known that post-addition of cinnamic acids to a polyvinyl acetate solution after polymerization can produce polyvinyl alcohol that suppresses the generation of fish eyes and odors during molding (Patent Document 3). However, there are no known examples of cinnamic acids being used as inhibitors for controlled radical polymerization, and such a function has not been academically anticipated. [Prior art documents] [Patent documents]

[0011] [Patent Document 1] WO2017-170974 publication [Patent Document 2] Japanese Patent Application Laid-Open No. 2014-129503 [Patent Document 3] Japanese Patent Application Laid-Open No. 2002-053728 [Non-patent literature]

[0012] [Non-Patent Document 1] Highly Efficient Cobalt-Mediated Radical Polymerization of Vinyl Acetate, Angewandte Chemie International Edition, 2005, vol.44, p1101-1104 [Non-patent document 2] Radical copolymerization of alkyl cinnamates and alkyl atropates, Journal of Industrial Chemistry, Vol. 70, No. 11, 1967, pp. 1941-1944 Summary of the Invention [Problem to be solved by the invention]

[0013] The present invention has been made to solve the above-mentioned problems, and aims to provide a method for producing a polymer that is low-toxicity, environmentally friendly, has high polymerization controllability, yields a high-molecular-weight polymer, and is low-cost. Another object of the present invention is to provide a composition for radical polymerization and a radical polymerization controller that are suitably used in such a production method. [Means for solving the problem]

[0014] The above-mentioned problems are solved by providing a method for producing a polymer, which comprises a polymerization step of obtaining a polymer by performing controlled radical polymerization of a monomer (Y) in the presence of an organic compound (A) represented by the following formula (I) and a radical generator (B), wherein the molar ratio of (B) to (A) (B / A) is 0.5 to 20:

[0015] [ka] [In formula (I), R 1 is an alkenyl group or an aryl group, and R 2 is a group represented by the following formula (II) or (III), and R 1 and R 2 may be linked to each other to form a ring.

[0016] [ka] [In formula (II), R 3 represents a hydrogen atom, a halogen atom, an alkyl group, an aryl group, an alkenyl group, an alkoxy group, an amino group, a nitro group, a cyano group, an acetyl group, a trifluoromethyl group, or a hydroxyl group, and * represents a bond.

[0017] [ka] [In formula (III), R 3 has the same meaning as in formula (II), and * indicates a bond.

[0018] At this time, R 1is preferably an aryl group. It is also preferable that the organic compound (A) is in the E form. It is also preferable that the organic compound (A) is represented by the following formula (IV).

[0019] [ka] [In formula (IV), R 3 is the same as in formula (II), and R 4 is a hydrogen atom, an alkyl group, an alkoxy group, or a hydroxyl group.

[0020] At this time, R 4 is preferably a hydrogen atom. 3 is preferably a methoxy group or a hydroxyl group. It is also preferable that the molar ratio (Y / A) of the monomer (Y) to the organic compound (A) is 300 to 30,000.

[0021] In the above-mentioned production method, the monomer (Y) preferably contains an olefin, a vinyl ester, acrylic acid, an acrylic acid ester, an acrylamide monomer, a styrene monomer, an N-vinylamide monomer, or a dicarboxylic acid monomer. In this case, it is more preferable that the production method comprises a polymerization step of obtaining a vinyl ester polymer by controlled radical polymerization of a vinyl ester in the presence of an organic compound (A) and a radical generator (B), and a saponification step of obtaining a vinyl alcohol polymer by saponifying the obtained vinyl ester polymer.

[0022] It is more preferable that the production method includes a polymerization step of sequentially carrying out controlled radical polymerization of a vinyl ester and controlled radical polymerization of a vinyl ester and a monomer other than a vinyl ester in the presence of an organic compound (A) and a radical generator (B) to obtain a vinyl ester-based block copolymer, and a saponification step of saponifying the obtained vinyl ester-based block copolymer to obtain a vinyl alcohol-based block copolymer.

[0023] The above-mentioned problems can also be solved by providing a composition for radical polymerization, which contains an organic compound (A) represented by the following formula (I) and a radical generator (B), and the molar ratio of (B) to (A) (B / A) is 0.5 to 20.

[0024] [ka] [In formula (I), R 1 is an alkenyl group or an aryl group, and R 2 is a group represented by the following formula (II) or (III), and R 1 and R 2 may be linked to each other to form a ring.

[0025] [ka] [In formula (II), R 3 represents a hydrogen atom, a halogen atom, an alkyl group, an aryl group, an alkenyl group, an alkoxy group, an amino group, a nitro group, a cyano group, an acetyl group, a trifluoromethyl group, or a hydroxyl group, and * represents a bond.

[0026] [ka] [In formula (III), R 3 has the same meaning as in formula (II), and * indicates a bond.

[0027] In this case, it is preferable that the composition for radical polymerization further contains a monomer (Y), and the molar ratio (Y / A) of the monomer (Y) to the organic compound (A) is 300 to 30,000.

[0028] The above-mentioned problems can also be solved by providing a radical polymerization inhibitor comprising an organic compound (A) represented by the following formula (I):

[0029] [ka] [In formula (I), R 1is an alkenyl group or an aryl group, and R 2 is a group represented by the following formula (II) or (III), and R 1 and R 2 may be linked to each other to form a ring.

[0030] [ka] [In formula (II), R 3 represents a hydrogen atom, a halogen atom, an alkyl group, an aryl group, an alkenyl group, an alkoxy group, an amino group, a nitro group, a cyano group, an acetyl group, a trifluoromethyl group, or a hydroxyl group, and * represents a bond.

[0031] [ka] [In formula (III), R 3 has the same meaning as in formula (II), and * indicates a bond.

[0032] A polymer having a terminal structure represented by the following formula (V) or (VI) is a preferred embodiment of the present invention.

[0033] [ka] [In formula (V), R 1 is an alkenyl group or an aryl group, and R 2 is a group represented by the following formula (II) or (III), and R 1 and R 2 may be linked to each other to form a ring. * indicates a bond.]

[0034] [ka] [In formula (VI), R 1 and R 2 has the same meaning as in formula (V), and * indicates a bond.

[0035] [ka] [In formula (II), R 3 represents a hydrogen atom, a halogen atom, an alkyl group, an aryl group, an alkenyl group, an alkoxy group, an amino group, a nitro group, a cyano group, an acetyl group, a trifluoromethyl group, or a hydroxyl group, and * represents a bond.

[0036] [ka] [In formula (III), R 3 has the same meaning as in formula (II), and * indicates a bond. [Effects of the Invention]

[0037] The organic compound (A) used in the production method of the present invention is highly safe, has high polymerization controllability, and is inexpensive. Therefore, this production method makes it possible to synthesize a high-molecular-weight, highly safe polymer while precisely controlling the molecular arrangement, terminal structure, etc. Furthermore, this production method is low-toxicity, environmentally friendly, does not require a step of removing the organic compound (A), and is low-cost. The radical polymerization composition and radical polymerization controller of the present invention are suitable for use in such polymer production methods. [Brief explanation of the drawings]

[0038] [Figure 1] 1 is a diagram in which the number average molecular weight (Mn) is plotted against the conversion rate of vinyl acetate in Example 1. FIG. DETAILED DESCRIPTION OF THE INVENTION

[0039] The present invention provides a method for producing a polymer, which comprises a polymerization step of obtaining a polymer by performing controlled radical polymerization of a monomer (Y) in the presence of an organic compound (A) represented by the following formula (I) and a radical generator (B), wherein the molar ratio of (B) to (A) (B / A) is 0.5 to 20.

[0040] [ka]

[0041] [In formula (I), R 1 is an alkenyl group or an aryl group, and R 2 is a group represented by the following formula (II) or (III), and R 1 and R 2 may be linked to each other to form a ring.

[0042] In the polymerization step, a polymer is obtained by controlled radical polymerization of a monomer (Y) in the presence of an organic compound (A) represented by the above formula (I) and a radical generator (B). The controlled radical polymerization employed in the production method of the present invention is a polymerization reaction in which the propagating radical terminal (active species) is in equilibrium with a covalently bonded species (dormant species) bonded to a radical control agent, and the reaction proceeds. In the production method of the present invention, the organic compound (A) represented by the above formula (I) functions as a radical control agent. The use of the organic compound (A) allows for high-molecular-weight polymers to be obtained while precisely controlling the molecular arrangement, terminal structure, etc. Furthermore, since the organic compound (A) is inexpensive and highly safe, having been industrially used as a food additive or flavoring, a step of removing the organic compound (A) is not required. Therefore, the production method of the present invention is environmentally friendly and cost-effective.

[0043] In the above formula (I), R 1 is an alkenyl group or an aryl group, and is preferably an aryl group.

[0044] The number of carbon atoms in the aryl group is preferably 6 to 15. The number of carbon atoms is more preferably 13 or less, even more preferably 12 or less, and particularly preferably 10 or less. Examples of the aryl group include a phenyl group, a biphenyl group, a naphthyl group, an anthryl group, an indenyl group, a fluorenyl group, a phenanthryl group, an indacenyl group, a phenalenyl group, an azulenyl group, a pyridyl group, and a furyl group, with a phenyl group being preferred. The aryl group may have a substituent, provided that the effect of the present invention is not impaired. Examples of such a substituent include an alkoxy group, an amino group (including a monoalkylamino group and a dialkylamino group), a carboxyl group, an ester group, a silyl group, a sulfanyl group, a cyano group, a nitro group, a sulfo group, a formyl group, an aryl group, a halogen atom, a hydroxyl group, an ether group, and an alkenyl group, with an alkyl group and an alkoxy group being preferred. Examples of the alkyl group and the alkoxy group include R in formula (II). 3 Examples of the aryl group that can be used include those described below. From the standpoint of being superior in terms of the environment and safety, it is preferable that the aryl group does not have a substituent.

[0045] The alkenyl group preferably has 2 to 10 carbon atoms. The number of carbon atoms is more preferably 8 or less. Meanwhile, the number of carbon atoms is more preferably 4 or more. The alkenyl group may be a linear or branched alkenyl group, or a cyclic cycloalkenyl group. Examples of the alkenyl group include linear or branched alkenyl groups such as vinyl, allyl, methylvinyl, propenyl, butenyl, pentenyl, and hexenyl groups; and cycloalkyl groups such as cyclopropenyl, cyclobutenyl, cyclopentenyl, and cyclohexenyl groups. Of these, the alkenyl group is preferably a cycloalkenyl group, and more preferably a cyclohexenyl group. The alkenyl group may have a substituent, provided that the effects of the present invention are not impaired. Examples of such a substituent include those described above as the substituent for the aryl group.

[0046] In the above formula (I), R 2 is a group represented by the following formula (II) or (III), and a group represented by the following formula (II) is preferred.

[0047] [ka] [In formula (II), R 3 represents a hydrogen atom, a halogen atom, an alkyl group, an aryl group, an alkenyl group, an alkoxy group, an amino group, a nitro group, a cyano group, an acetyl group, a trifluoromethyl group, or a hydroxyl group, and * represents a bond.

[0048] [ka] [In formula (III), R 3 has the same meaning as in formula (II), and * indicates a bond.

[0049] In the above formula (II), R 3 represents a hydrogen atom, a halogen atom, an alkyl group, an aryl group, an alkenyl group, an alkoxy group, an amino group (including a monoalkylamino group and a dialkylamino group), a nitro group, a cyano group, an acetyl group, a trifluoromethyl group, or a hydroxyl group, preferably a hydrogen atom, an alkyl group, an aryl group, an alkoxy group, or a hydroxyl group, more preferably an alkyl group, an alkoxy group, or a hydroxyl group, and most preferably an alkoxy group or a hydroxyl group.

[0050] The number of carbon atoms in the alkyl group is preferably 1 to 10. The number of carbon atoms is more preferably 8 or less, even more preferably 6 or less, even more preferably 4 or less, and particularly preferably 2 or less. The alkyl group may be a straight-chain or branched-chain alkyl group, or a cyclic cycloalkyl group. Examples include straight-chain or branched-chain alkyl groups such as methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, n-pentyl, isopentyl, neopentyl, tert-pentyl, n-hexyl, isohexyl, 2-ethylhexyl, n-heptyl, n-octyl, n-nonyl, and n-decyl; and cycloalkyl groups such as cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, cycloheptanyl, cyclooctanyl, cyclononanyl, and cyclodecanyl. Among these, methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, and tert-butyl groups are preferred, and methyl is more preferred. The alkyl group may have a substituent within a range that does not impair the effects of the present invention. Examples of such a substituent include R 1 Examples of the substituent on the aryl group used as the alkyl group include those mentioned above. From the standpoint of being superior in terms of the environment and safety, it is preferable that the alkyl group does not have a substituent.

[0051] The number of carbon atoms in the aryl group is preferably 6 to 15. The number of carbon atoms is more preferably 13 or less, further preferably 12 or less, and particularly preferably 10 or less. The aryl group may be R 1 Examples of the compounds that can be used include those mentioned above.

[0052] The number of carbon atoms in the alkoxy group is preferably 1 to 10. The number of carbon atoms is more preferably 8 or less, even more preferably 6 or less, even more preferably 4 or less, and particularly preferably 1. Examples of the alkoxy group include methoxy, ethoxy, propoxy, isopropoxy, butoxy, isobutoxy, sec-butoxy, tert-butoxy, pentyloxy, isopentyloxy, neopentyloxy, hexyloxy, cyclohexyloxy, heptyloxy, octyloxy, nonyloxy, and decyloxy. Among these, methoxy, ethoxy, propoxy, isopropoxy, butoxy, isobutoxy, sec-butoxy, and tert-butoxy are preferred, and methoxy is more preferred. The alkoxy group may have a substituent, as long as it does not impair the effects of the present invention. Examples of such a substituent include R 1 Examples of the substituent of the aryl group used as the substituent include those mentioned above. From the standpoint of being superior in terms of the environment and safety, it is preferable that the alkoxy group does not have a substituent.

[0053] The organic compound (A) represented by formula (I) may be either the E-isomer or the Z-isomer. Preferably, the E-isomer is used; that is, the controlled radical polymerization of the monomer (Y) is carried out in the presence of the organic compound (A) in the E-isomer and the radical generator (B). In this case, the organic compound (A) in the Z-isomer may be present as an optional component. When the organic compound (A) in the Z-isomer is present, the molar ratio (E / E+Z) of the E-isomer to the total of the E-isomer and the Z-isomer is preferably greater than 0.5, more preferably 0.7 or greater, and even more preferably 0.8 or greater. It is also preferred that the molar ratio (B / E+Z) of the radical generator (B) to the total of the E-isomer and the Z-isomer is in the same range as the molar ratio (B / A) described below. It is also preferred that the molar ratio (Y / E+Z) of the monomer (Y) to the total of the E-isomer and the Z-isomer is in the same range as the molar ratio (Y / A) described below.

[0054] It is particularly preferable that the organic compound (A) represented by the above formula (I) is represented by the following formula (IV).

[0055] [ka] [In formula (IV), R 3 is the same as in formula (II), and R 4 is a hydrogen atom, an alkyl group, an alkoxy group, or a hydroxyl group.

[0056] In the above formula (IV), R 4 is a hydrogen atom, an alkyl group, an alkoxy group, or a hydroxyl group. 4 is preferably a hydrogen atom. 4 The bonding position of R is not particularly limited. 4 The alkyl and alkoxy groups used as R 3 Examples of the compounds that can be used include those mentioned above.

[0057] In the above formula (I), R 1 and R 2 may be linked to each other to form a ring. An example of the organic compound (A) having such a ring formed therein is one represented by the following formula (VII).

[0058] [ka]

[0059] The radical generator (B) used in the polymerization step may be selected from conventionally known azo radical generators, peroxide radical generators, redox radical generators, etc. Examples of azo radical generators include 2,2'-azobisisobutyronitrile, 2,2'-azobis(2,4-dimethylvaleronitrile), and 2,2'-azobis(4-methoxy-2,4-dimethylvaleronitrile). Examples of peroxide radical generators include percarbonate compounds such as diisopropyl peroxydicarbonate, di-2-ethylhexyl peroxydicarbonate, and diethoxyethyl peroxydicarbonate; perester compounds such as t-butyl peroxyneodecanate, α-cumyl peroxyneodecanate, and t-butyl peroxyneodecanate; acetylcyclohexylsulfonyl peroxide; diisobutyryl peroxide; and 2,4,4-trimethylpentyl-2-peroxyphenoxyacetate. Furthermore, the radical generator can be prepared by combining the above-mentioned radical generator with a peroxide such as potassium persulfate, ammonium persulfate, or hydrogen peroxide. Redox radical generators include those obtained by combining the above-mentioned peroxide with a reducing agent such as sodium hydrogen sulfite, sodium hydrogen carbonate, tartaric acid, L-ascorbic acid, or Rongalit.

[0060] Polymerization methods include well-known methods such as bulk polymerization, solution polymerization, suspension polymerization, and emulsion polymerization. Among these, bulk polymerization, which involves polymerization without a solvent, and solution polymerization, which involves polymerization in various organic solvents, are commonly used. Bulk polymerization, which does not use a solvent or a dispersion medium, is preferred from the viewpoint of suppressing the decrease in propagating radical ends due to chain transfer reactions to the solvent or dispersion medium. On the other hand, solution polymerization may be preferable from the viewpoint of adjusting the viscosity of the reaction solution and controlling the polymerization rate. Examples of organic solvents used as solvents in solution polymerization include esters such as methyl acetate and ethyl acetate; aromatic hydrocarbons such as benzene and toluene; lower alcohols such as methanol and ethanol; and carbonates such as dimethyl carbonate and diethyl carbonate. Of these, esters, aromatic hydrocarbons, and dimethyl carbonate are preferred to prevent chain transfer. Furthermore, when the monomer (Y) contains vinyl acetate, alkali treatment in methanol is often performed after polymerization. Therefore, methanol is also preferred as a polymerization solvent in consideration of processability. The amount of solvent used can be determined based on the number-average molecular weight of the target polymer and the viscosity of the reaction solution. For example, the mass ratio [solvent / monomer (Y)] is selected from the range of 0.01 to 10.

[0061] In the controlled radical polymerization used in the present invention, radicals generated by decomposition of the radical generator (B) first combine with a small number of monomers (Y) to produce short-chain polymers. The resulting radicals at the growing end of the polymer then combine with the organic compound (A), forming dormant species in which the organic compound (A) is covalently bonded to the polymer end. For a certain period after the start of the reaction, short-chain polymers are produced and converted to dormant species, and no substantial polymerization takes place. This period is called the induction period. After the organic compound (A) is consumed, the reaction enters a growth period in which polymerization proceeds, and the molecular weights of most molecular chains in the reaction system increase at the same rate in proportion to the polymerization time. The time required for the polymerization of the monomer (Y), including the induction period and growth period, is usually 0.5 to 30 hours.

[0062] As described above, in the controlled radical polymerization of the present invention, theoretically, one polymer chain is produced from one molecule of the added organic compound (A). Therefore, the amount of organic compound (A) added to the reaction solution is determined taking into consideration the desired number-average molecular weight and conversion rate. From the viewpoint of obtaining a high-molecular-weight polymer, the molar ratio (Y / A) of the organic compound (A) to the monomer (Y) in the polymerization step is preferably 300 or more, more preferably 1000 or more, even more preferably 2000 or more, even more preferably 4000 or more, and particularly preferably 6000 or more. On the other hand, from the viewpoint of improving the activity of the propagating radical terminal, the molar ratio (Y / A) is preferably 30,000 or less, more preferably 25,000 or less, and even more preferably 20,000 or less. When the organic compound (A) or the monomer (Y) is added in multiple portions, the molar ratio (Y / A) is calculated using the total amount of each portion.

[0063] In the polymerization process, the ratio (B / A) of the radical generator (B) to the organic compound (A) is 0.5 to 20. If the number of moles of radicals generated is not greater than the number of moles of the organic compound (A), the polymerization reaction proceeds solely by the thermal dissociation of the organic compound (A) from the dormant species, resulting in a very slow polymerization rate depending on the reaction temperature. Therefore, considering that the radical generator (B) generates two radicals, both the radical generator (B) and the organic compound (A) must be added to the reaction solution in the polymerization process so that the ratio (B / A) of the radical generator (B) to the organic compound (A) is 0.5 or greater. Generally, the amount of active radicals supplied from the radical generator depends on the efficiency (initiator efficiency) of the radical generator, so in reality, some radical generator is deactivated without being used to form dormant. Therefore, the molar ratio (B / A) of the radical generator (B) to the organic compound (A) is preferably 0.6 or greater, more preferably 0.8 or greater. On the other hand, if the number of moles of radicals generated is too much greater than the number of moles of organic compound (A), the proportion of uncontrolled radical polymerization increases, and polymerization controllability decreases. The molar ratio of (B) to (A) (B / A) is preferably 15 or less, more preferably 10 or less, and even more preferably 5 or less. When the organic compound (A) or the radical generator (B) is added in multiple portions, the molar ratio (B / A) is calculated using the total amount of each portion.

[0064] The monomer contained in the monomer (Y) used in the polymerization step is not particularly limited as long as it has radical polymerizability. Examples of the monomer include olefins such as ethylene, propylene, and isobutylene; halogenated olefins such as vinyl chloride, vinyl fluoride, vinylidene chloride, and vinylidene fluoride; vinyl formate, vinyl acetate, vinyl trifluoroacetate, vinyl propionate, vinyl valerate, vinyl butyrate, vinyl isobutyrate, vinyl pivalate, vinyl caprate, vinyl laurate, vinyl stearate, vinyl benzoate, and vinyl versatate. vinyl esters such as vinyl acrylate; vinylidene cyanide; acrylic acid; methacrylic acid; acrylic acid esters such as methyl acrylate, ethyl acrylate, N-propyl acrylate, i-propyl acrylate, N-butyl acrylate, i-butyl acrylate, t-butyl acrylate, 2-ethylhexyl acrylate, dodecyl acrylate, and octadecyl acrylate; methacrylates such as methyl methacrylate, ethyl methacrylate, butyl methacrylate, 2-ethylhexyl methacrylate, dodecyl methacrylate, and 2-hydroxyethyl methacrylate. Acrylic acid esters; dimethylaminoethyl acrylate, dimethylaminoethyl methacrylate, and their quaternized derivatives; acrylamide-based monomers such as acrylamide, N-methylolacrylamide, N,N-dimethylacrylamide, acrylamido-2-methylpropanesulfonic acid, and its sodium salt; methacrylamide-based monomers such as methacrylamide, N,N-dimethylmethacrylamide, and trimethyl[3-(methacryloylamino)propyl]aminium chloride; styrene, α-methylstyrene, p-styrene Styrenic monomers such as sulfonic acids and their sodium salts and potassium salts; N-vinylamide monomers such as N-vinylpyrrolidone, N-vinylformamide, N-vinylacetamide, and N-vinylcaprolactam; allyl monomers such as allyl acetate, allyl chloride, 3,4-diacetoxy-1-butene, 2-methylene-1,3-propanediol, 2-methylene-1,3-propanediol diacetate, allyl alcohol, and dimethylallyl alcohol; vinyl cyanide monomers such as acrylonitrile and methacrylonitrile;Preferred are vinyl ether monomers such as alkyl (C1-C18) vinyl ether, hydroxyalkyl vinyl ether, and alkoxyalkyl vinyl ether; and dicarboxylic acid monomers such as maleic acid, monomethyl maleate, dimethyl maleate, maleic anhydride, itaconic acid, monomethyl itaconate, dimethyl itaconate, and itaconic anhydride. Olefins, vinyl esters, acrylic acid, acrylic acid esters, acrylamide monomers, styrene monomers, N-vinylamide monomers, and dicarboxylic acid monomers are more preferred. Vinyl esters, styrenes, and N-vinylpyrrolidone are even more preferred, vinyl esters, and N-vinylpyrrolidone are particularly preferred, and vinyl esters are most preferred. Monomer (Y) may contain one of these monomers or two or more of them. It is preferred that monomer (Y) contains one of these monomers as a major component. Here, "major component" refers to the monomer contained in monomer (Y) with the highest content. The content of the main monomer in the monomer (Y) is preferably 30 mol% or more, more preferably 50 mol% or more, even more preferably 70 mol% or more, and particularly preferably 80 mol% or more.

[0065] The vinyl ester is preferably vinyl acetate from an economical viewpoint, and the acrylic ester is preferably methyl acrylate from an economical viewpoint.

[0066] In the production method of the present invention, a homopolymer may be obtained by using one type of monomer as the monomer (Y), or a copolymer may be obtained by using two or more types of monomers. The copolymer may be either a random copolymer or a block copolymer. Furthermore, the polymer obtained by the production method of the present invention may be either a branched or linear polymer, but a linear polymer is preferred in that it can take advantage of the high polymerization controllability provided by the organic compound (A).

[0067] The method for mixing the organic compound (A), the radical generator (B), and the monomer (Y) is not particularly limited, as long as it is a method that can generate dormant species and control the increase in molecular weight of the polymer. Examples of such methods include adding the organic compound (A) and the radical generator (B) to the monomer (Y), mixing the organic compound (A) and the radical generator (B) and then mixing the resulting mixture with the monomer (Y), mixing the organic compound (A), the radical generator (B), and the monomer (Y) all at once, and mixing the organic compound (A) and the monomer (Y) and then mixing the resulting mixture with the radical generator (B). The organic compound (A), the radical generator (B), and the monomer (Y) may also be mixed in portions. For example, a method may be used in which the organic compound (A), the radical generator (B), and a portion of the monomer (Y) are mixed to generate dormant species in which the organic compound (A) is covalently bonded to a short-chain polymer terminal, and then the dormant species is mixed with the remainder of the monomer (Y) to increase the molecular weight.The dormant species may also be isolated as a macroinitiator and then mixed with the remainder of the monomer (Y) to increase the molecular weight.

[0068] The polymerization temperature is preferably, for example, 0 to 80°C. If the polymerization temperature is below 0°C, the polymerization rate may be insufficient, which may result in a decrease in productivity. From this point of view, the polymerization temperature is more preferably 10°C or higher, and even more preferably 20°C or higher. On the other hand, if the polymerization temperature exceeds 80°C, the controllability of the radical polymerization may decrease. From this point of view, the polymerization temperature is more preferably 70°C or lower, and even more preferably 65°C or lower.

[0069] From the viewpoint of further improving polymerization controllability, when the conversion rate of the monomer (Y) is 5.0%, the ratio (Mn / theoretical Mn) of the number average molecular weight (Mn) (measured) to the theoretical number average molecular weight (theoretical Mn) of the polymer is preferably 10.0 or less, more preferably 8.0 or less, even more preferably 6.0 or less, even more preferably 5.0 or less, particularly preferably 4.5 or less, and most preferably 4.0 or less. On the other hand, from the viewpoint of productivity, when the conversion rate of the monomer (Y) is 5.0%, the ratio (Mn / theoretical Mn) of the polymer is preferably 0.5 or more, more preferably 0.8 or more. The conversion rate of the monomer (Y) at the end of polymerization is not particularly limited and may be adjusted depending on the amount of the organic compound (A) and the monomer (Y) added, the target number average molecular weight, etc., but is usually 3 to 50%. The conversion rate is preferably 10% or more, more preferably 20% or more. The number average molecular weight (Mn) (measured value) of the polymer when the conversion rate is 5.0% is calculated as follows. The polymer is subjected to GPC (gel permeation chromatography) measurement multiple times from the start of polymerization to the end of polymerization (at least once when the conversion rate is 1.0% or more and less than 5.2%) to determine the number average molecular weight (Mn) at multiple conversion rates. The number average molecular weight (Mn) is then plotted against the conversion rate, and the number average molecular weight (Mn) of the polymer when the conversion rate is 5.0% is calculated from a straight line passing through two points close to 5.0%. However, at least one of the two points must be a point where the conversion rate is 1.0% or more and less than 5.2%. Specifically, the method described in the Examples below is employed. The theoretical number average molecular weight (theoretical Mn) of the polymer is calculated using the following formula: Theoretical Mn = molar ratio of monomer (Y) to organic compound (A) (Y / A) × average molecular weight of monomer (Y) [g / mol] × (conversion rate [%] / 100)

[0070] In order to take advantage of the high polymerization controllability of the production method of the present invention, it is preferable to produce a block copolymer in the polymerization step. Specifically, in the polymerization step, it is preferable to sequentially carry out controlled polymerization of monomer (Ya) and controlled polymerization of monomer (Yb) other than monomer (Ya) in the presence of organic compound (A) and radical generator (B) to obtain a block copolymer containing polymer block (a) containing monomer (Ya) units and polymer block (b) containing monomer (Yb) units. It is more preferable to sequentially carry out controlled polymerization of monomer (Ya) and controlled polymerization of monomer (Ya) and monomer (Yb) in the presence of organic compound (A) and radical generator (B) to obtain a block copolymer containing polymer block (a) containing monomer (Ya) units and polymer block (ab) containing monomer (Ya) units and monomer (Yb) units. The polymerization step is described below.

[0071] In the polymerization step, first, the polymerization of the monomer (Ya) is initiated by mixing the monomer (Ya), optionally a monomer (Yc) other than the monomer (Ya) and the monomer (Yb), the organic compound (A), and the radical generator (B) by the method described above. After the number-average molecular weight of the polymer block (a) containing the monomer (Ya) reaches a target value, the monomer (Yb) is polymerized to synthesize the polymer block (b) containing the monomer (Yb) unit. At this time, the remaining monomer (Ya) may be removed, and then the monomer (Yb) is added to the reaction solution to polymerize the monomer (Yb), thereby synthesizing the polymer block (b) containing the monomer (Yb) unit. Alternatively, the monomer (Yb) may be added to the reaction solution without removing the monomer (Ya), and the remaining monomer (Ya) may be copolymerized with the monomer (Yb) to synthesize a copolymer block (ab) containing the monomer (Ya) unit and the monomer (Yb) unit. When the monomer (Yb) is added, an additional monomer (Ya) or another monomer (Yc) may be added as necessary.

[0072] Alternatively, first, the polymer block (ab) may be synthesized by mixing the monomer (Ya), the monomer (Yb), and, if necessary, another monomer (Yc), the organic compound (A), and the radical generator (B), and after the monomer (Yb) is completely consumed or the remaining monomer (Yb) is removed, the polymer block (a) may be synthesized by polymerizing the monomer (Ya).

[0073] In this way, a diblock copolymer may be obtained by synthesizing the polymer block (a) and the polymer block (b) or the copolymer block (ab), or a ternary or higher multiblock copolymer may be obtained by repeatedly polymerizing the monomer (Ya), the monomer (Yb), or another monomer (Yc). From the viewpoint of cost, the block copolymer is preferably a diblock copolymer, a triblock copolymer, or a tetrablock copolymer, more preferably a diblock copolymer or a triblock copolymer, and even more preferably a diblock copolymer. The bonding form of each block is preferably linear.

[0074] In order to easily obtain the performance derived from each block, the ratio of the number average molecular weight (Mn) of each block to the number average molecular weight (Mn) of the block copolymer (Mn of block / Mn of block copolymer) is preferably 0.01 to 0.99. The ratio (Mn of block / Mn of block copolymer) is more preferably 0.05 or more, and even more preferably 0.1 or more. On the other hand, the ratio (Mn of block / Mn of block copolymer) is more preferably 0.95 or less, and even more preferably 0.9 or less.

[0075] The content of the monomer (Ya) units in the polymer block (a) is preferably 50 mol% or more, more preferably 70 mol% or more, even more preferably 80 mol% or more, and particularly preferably 90 mol% or more. The content of the monomer (Yb) units in the polymer block (a) is preferably less than 10 mol%, more preferably less than 5 mol%, and even more preferably less than 1 mol%. The content of the monomer (Yb) units in the polymer block (b) is preferably 50 mol% or more, more preferably 70 mol% or more, even more preferably 80 mol% or more, and particularly preferably 90 mol% or more. The content of the monomer (Ya) units in the polymer block (b) is preferably less than 10 mol%, more preferably less than 5 mol%, and even more preferably less than 1 mol%. The content of the monomer (Ya) units in the polymer block (ab) is preferably 1 to 99 mol%, more preferably 5 to 99 mol%, and even more preferably 10 to 90 mol%. The content of the monomer (Yb) unit in the polymer block (ab) is preferably from 1 to 99 mol %, more preferably from 5 to 99 mol %, and even more preferably from 10 to 90 mol %.

[0076] The monomer (Ya), the monomer (Yb), and the other monomer (Yc) are not particularly limited, and the monomers described above as the monomer (Y) can be used in appropriate combination. Among them, it is preferable to use the vinyl ester as one of the monomers (Ya) and (Yb). The other monomer used together with the vinyl ester is not particularly limited as long as it is a monomer other than a vinyl ester, but is preferably the acrylic ester, the olefin, or the acrylic acid.

[0077] Among these, it is particularly preferred to obtain a vinyl ester-based block copolymer containing a vinyl ester polymer block and a polymer block containing a vinyl ester unit and a unit derived from a monomer other than the vinyl ester by sequentially carrying out controlled radical polymerization of a vinyl ester and controlled radical polymerization of a vinyl ester and a monomer other than the vinyl ester in the presence of an organic compound (A) and a radical generator (B) in the polymerization step.

[0078] In the polymerization step, when the number average molecular weight of the polymer or the conversion rate of the monomer (Y) reaches a target value, a polymerization terminator is preferably added to terminate the polymerization reaction. Examples of the polymerization terminator include 1,1-diphenylethylene; hydroxyaromatic compounds such as p-methoxyphenol, hydroquinone, cresol, t-butylcatechol, and p-nitrosophenol; quinone compounds such as benzoquinone and naphthoquinone; conjugated carboxylic acids such as muconic acid and sorbic acid; thioethers such as phenothiazine, distearyl thiodipropionate, and dilauryl thiodipropionate; aromatic amines such as p-phenylenediamine and N-nitrosodiphenylamine; nitroxides such as 2,2,6,6-tetramethylpiperidine 1-oxyl and 4-hydroxy-2,2,6,6-tetramethylpiperidine 1-oxyl; and transition metal salts such as copper acetate, copper dithiocarbamate, and manganese acetate. Among these, 1,1-diphenylethylene, sorbic acid and benzoquinone are preferred, and 1,1-diphenylethylene is more preferred.

[0079] The number of moles of the polymerization terminator added is preferably 1 to 100 moles per mole of the added organic compound (A). If the number of moles of the polymerization terminator is too small, radicals at the polymer terminals may not be sufficiently captured, which may result in a deterioration in the color tone of the resulting polymer. On the other hand, if the number of moles of the polymerization terminator is too large, the production cost may increase.

[0080] The temperature of the reaction solution in the termination step may be any temperature at which the polymerization terminator can react with the terminal radicals of the polymer, and is preferably 0 to 80° C. The time required for the termination step is usually 1 minute to 5 hours.

[0081] After the polymerization step, a removal step may be carried out to remove the organic compound (A) contained in the obtained polymer, but it is preferable not to carry out such a removal step from the viewpoint of a good balance between environmental aspects, safety, and cost. Since the organic compound (A) is highly safe, the safety of the obtained polymer is high even if a removal step is not carried out.

[0082] As described above, the monomer (Y) used in the polymerization step preferably contains a vinyl ester. That is, in the polymerization step, it is preferable to obtain a vinyl ester polymer by controlled radical polymerization of a vinyl ester in the presence of an organic compound (A) and a radical generator (B). Examples of the vinyl ester polymer include a homopolymer of a vinyl ester, a random copolymer containing vinyl ester units and units derived from a monomer other than a vinyl ester, and a vinyl ester block copolymer containing a polymer block (a) containing vinyl ester units and a polymer block (b) containing units derived from a monomer other than a vinyl ester. The vinyl ester polymer thus obtained is suitable for a variety of applications.

[0083] It is also preferable to carry out a saponification step in which the vinyl ester polymer is saponified to convert vinyl ester units into vinyl alcohol units, thereby obtaining a vinyl alcohol polymer.

[0084] In the saponification step, for example, the vinyl ester polymer can be saponified in a state where it is dissolved in alcohol to obtain a vinyl alcohol polymer. When the vinyl ester polymer contains acrylic ester units, the acrylic ester units can be converted to acrylic acid units by adjusting the saponification conditions. In addition, the acrylic ester units or acrylic acid units may form a lactone ring with adjacent vinyl alcohol units.

[0085] Examples of the alcohol used in the saponification reaction include lower alcohols such as methanol and ethanol, with methanol being particularly preferred. The alcohol may be a hydrous alcohol or a dehydrated alcohol. The alcohol used in the saponification reaction may contain a solvent such as acetone, an ester such as methyl acetate or ethyl acetate, or toluene. Examples of catalysts used in the saponification reaction include alkali metal hydroxides such as potassium hydroxide and sodium hydroxide; alkali catalysts such as sodium methylate; and acid catalysts such as mineral acids. The temperature of the saponification reaction is preferably in the range of 20 to 80°C. If a gel-like product precipitates as the saponification reaction proceeds, the product can be crushed, washed, and dried at this point to obtain a vinyl alcohol polymer.

[0086] The degree of saponification of the vinyl alcohol polymer may be adjusted depending on the application and is not particularly limited, but is usually 50 to 99.99 mol %. In the present invention, the degree of saponification refers to the ratio (mol %) of the total number of moles of vinyl alcohol units (including units derived from vinyl alcohol monomers forming lactone rings) to the total number of moles of vinyl ester units and vinyl alcohol units (including units derived from vinyl alcohol monomers forming lactone rings) in the vinyl alcohol polymer. The degree of saponification of the vinyl alcohol polymer 1 It can be determined by H-NMR measurement.

[0087] The total amount of vinyl ester units and vinyl alcohol units in the vinyl alcohol polymer is preferably 50 mol % or more, more preferably 70 mol % or more, and even more preferably 80 mol % or more.

[0088] When the vinyl ester block copolymer containing a polymer block (a) containing vinyl ester units and a polymer block (b) containing units derived from a monomer other than vinyl ester is saponified, a vinyl alcohol block copolymer containing a polymer block (a') containing vinyl alcohol units and a polymer block (b') containing units derived from a monomer other than vinyl ester is obtained. Furthermore, when the vinyl ester block copolymer containing a polymer block (a) containing vinyl ester units and a copolymer block (ab) containing vinyl ester units and units derived from a monomer other than vinyl ester is saponified, a vinyl alcohol block copolymer containing a vinyl alcohol polymer block (a') and a copolymer block (ab') containing vinyl alcohol units and units derived from a monomer other than vinyl ester is obtained.

[0089] The number-average molecular weight (Mn) of the polymer obtained by the production method of the present invention is not particularly limited, but is preferably 1,000 or more. According to the production method of the present invention, it is possible to synthesize a high-molecular-weight polymer while precisely controlling the molecular arrangement, terminal structure, etc. Therefore, this production method is suitably used for producing a polymer with a high number-average molecular weight (Mn). The number-average molecular weight (Mn) of the polymer is more preferably 2,000 or more, even more preferably 4,000 or more, even more preferably 10,000 or more, particularly preferably 20,000 or more, and most preferably 40,000 or more. On the other hand, from the viewpoint of ease of handling, the number-average molecular weight (Mn) of the polymer is preferably 1,000,000 or less, more preferably 500,000 or less, and even more preferably 300,000 or less. The number-average molecular weight (Mn) and molecular weight distribution (Mw / Mn) were measured by GPC using polymethyl methacrylate as a standard substance. The column may be appropriately selected taking into consideration the solubility of the polymer in the solvent, etc., and a tetrahydrofuran-based column, an HFIP-based column, etc. are preferably used. Specific measurement methods are as described in the Examples.

[0090] The molecular weight distribution (Mw / Mn) of the polymer obtained by the production method of the present invention is not particularly limited, but is preferably 1.00 to 3.5. Polymerization by controlled radical polymerization can produce a polymer with a narrow molecular weight distribution. The molecular weight distribution (Mw / Mn) is more preferably 3.4 or less, even more preferably 3.3 or less, and particularly preferably 3.2 or less.

[0091] In the production method of the present invention, the use of organic compound (A) allows for high-level control of radical polymerization, making it possible to obtain high-molecular-weight polymers while precisely controlling the molecular arrangement, terminal structure, and the like. Furthermore, organic compound (A) is inexpensive and is used industrially as a food additive or flavoring, making it highly safe, eliminating the need for a step to remove organic compound (A). Therefore, the production method of the present invention is environmentally friendly and cost-effective. Taking advantage of the properties of the resulting polymers, they can be suitably used in applications such as hygiene, daily necessities, construction and civil engineering, industrial, agricultural, medical, and food applications.

[0092] A preferred embodiment of the present invention is a composition for radical polymerization comprising an organic compound (A) represented by the following formula (I) and a radical generator (B), wherein the molar ratio of (B) to (A) (B / A) is 0.5 to 20. By using this composition, radical polymerization of a monomer (Y) can be carried out with high control. In addition, this composition for radical polymerization is highly safe. Therefore, it can be suitably used in the radical polymerization of various monomers, including the above-mentioned method for producing a polymer. Examples of the organic compound (A), radical generator (B), and monomer (Y) used in the composition for radical polymerization include those described above as being used in the method for producing a polymer.

[0093] [ka] [In formula (I), R 1 is an alkenyl group or an aryl group, and R 2 is a group represented by the following formula (II) or (III), and R 1 and R 2may be linked to each other to form a ring.

[0094] [ka] [In formula (II), R 3 represents a hydrogen atom, a halogen atom, an alkyl group, an aryl group, an alkenyl group, an alkoxy group, an amino group, a nitro group, a cyano group, an acetyl group, a trifluoromethyl group, or a hydroxyl group, and * represents a bond.

[0095] [ka] [In formula (III), R 3 has the same meaning as in formula (II), and * indicates a bond.

[0096] The composition for radical polymerization preferably further contains a monomer (Y), in which the molar ratio (Y / A) of the monomer (Y) to the organic compound (A) is preferably 300 to 30,000.

[0097] A radical polymerization controller comprising an organic compound (A) represented by the following formula (I) is also a preferred embodiment of the present invention. Examples of the organic compound (A) used as the radical polymerization controller include those described above as being used in the polymer production process. Examples of the radical generator (B) and monomer (Y) used together with the radical polymerization controller in radical polymerization include those described above as being used in the polymer production process.

[0098] [ka]

[0099] [In formula (I), R 1 is an alkenyl group or an aryl group, and R 2 is a group represented by the following formula (II) or (III), and R 1 and R 2 may be linked to each other to form a ring.

[0100] [ka] [In formula (II), R 3 represents a hydrogen atom, a halogen atom, an alkyl group, an aryl group, an alkenyl group, an alkoxy group, an amino group, a nitro group, a cyano group, an acetyl group, a trifluoromethyl group, or a hydroxyl group, and * represents a bond.

[0101] [ka] [In formula (III), R 3 has the same meaning as in formula (II), and * indicates a bond.

[0102] A polymer having a terminal structure represented by the following formula (V) or (VI) is a preferred embodiment of the present invention. [ka] [In formula (V), R 1 is an alkenyl group or an aryl group, and R 2 is a group represented by the following formula (II) or (III), and R 1 and R 2 may be linked to each other to form a ring. * indicates a bond.]

[0103] [ka] [In formula (VI), R 1 and R 2 has the same meaning as in formula (V), and * indicates a bond.

[0104] [ka] [In formula (II), R 3 represents a hydrogen atom, a halogen atom, an alkyl group, an aryl group, an alkenyl group, an alkoxy group, an amino group, a nitro group, a cyano group, an acetyl group, a trifluoromethyl group, or a hydroxyl group, and * represents a bond.

[0105] [ka] [In formula (III), R 3 has the same meaning as in formula (II), and * indicates a bond. [Example]

[0106] The present invention will be explained in more detail below using examples.

[0107] [Organic compound (A)] ·trans-cinnamic acid Methyl cinnamate trans-Benzalacetone Cinnamic alcohol 4-Phenyl-2-butanone β-Ionone Coumarin [Radical generator (B)] [2,2'-Azobis(4-methoxy-2,4-dimethylvaleronitrile)] (V-70) [Monomer] Vinyl acetate (VAc) N-vinylpyrrolidone (VP) Methyl acrylate (MA) Ethylene (Et) Styrene (Sty) N,N-dimethylacrylamide (DEAA) Maleic anhydride (MAn) [Polymerization inhibitor] 1,1-Diphenylethylene (1,1-DPEt)

[0108] [Number average molecular weight (Mn)] The number average molecular weight (Mn) and molecular weight distribution (Mw / Mn) of the polymer were measured using a gel permeation chromatography device manufactured by Shimadzu Corporation. The measurement conditions were either: <Condition 1> Column: Showa Denko KF-806M tetrahydrofuran column Standard sample: Polymethyl methacrylate Solvent and mobile phase: tetrahydrofuran (THF) Flow rate: 1.0mL / min Temperature: 40℃ Sample solution concentration: 0.2% by mass (filtered through a 0.45 μm filter) Injection volume: 100μL Detector: RI <Condition 2> Column: Two HFIP columns "GMHHR-H(S)" manufactured by Tosoh Corporation connected in series Standard sample: Polymethyl methacrylate Solvent and mobile phase: Sodium trifluoroacetate-HFIP solution (concentration 20 mM) Flow rate: 0.2mL / min Temperature: 40℃ Sample solution concentration: 0.1 wt% (filtered through a 0.45 μm filter) Injection volume: 10μL Detector: RI

[0109] [Theoretical number average molecular weight (theoretical Mn)] The theoretical number average molecular weight (theoretical Mn) at a given conversion was calculated from the following formula. Theoretical Mn = molar ratio of monomer (Y) to organic compound (A) (Y / A) × average molecular weight of monomer (Y) [g / mol] × (conversion rate [%] / 100)

[0110] [Polymerization control] When the conversion rate of the monomer (Y) was 5.0%, the ratio (Mn / theoretical Mn) of the number average molecular weight (Mn) (measured) to the theoretical number average molecular weight (theoretical Mn) of the polymer was 10.0 or less, and Mn increased with increasing conversion rate. The number average molecular weight (Mn) (measured) of the polymer at the conversion rate of 5.0% was determined as follows. The number average molecular weight (Mn) at multiple conversion rates was determined by performing GPC (gel permeation chromatography) measurement of the polymer in the reaction solution multiple times from the start of polymerization to the end of polymerization (but at least once when the conversion rate was 1.0% or more and less than 5.2%). Figure 1 is a graph plotting the number average molecular weight (Mn) against the conversion rate in Example 1. As shown in Figure 1, the number average molecular weight (Mn) (horizontal axis, linear scale) was plotted against the conversion (horizontal axis, linear scale), and the number average molecular weight (Mn) of the polymer when the conversion was 5.0% was determined from the line passing through two points where the conversion was close to 5.0%, with at least one of the two points being at a conversion of 1.0% or more but less than 5.2%.

[0111] [Amount of Et dissolved in VAc] The amount of Et dissolved in VAc was calculated as follows: Table 1 in Nature Chemistry volume 6, pages 179-187 (2014) shows that copolymerization of VAc and Et was carried out under Et pressures of 10, 25, and 50 bar, and the Et mole fractions in the resulting VAc / Et random copolymers were 0.13, 0.33, and 0.54, respectively. The correlation between Et pressure (E) [bar] and the Et mole fraction (Fet) in the resulting copolymer was plotted for four points, including the origin (where the Et content is 0 when the Et pressure is 0), and the least-squares approximation curve was obtained, which is given by the following equation: Fet=0.0108E+0.0208

[0112] The molar ratio of VAc units to Et units contained in the VAc / Et copolymer (F=Fvac / Fet) is expressed by the following formula: F=(1-Fet) / Fet

[0113] Incidentally, the Polymer Handbook, fourth edition, page II / 273, states that the copolymerization reactivity ratios of VAc and Et are r(VAc) = 1.03 and r(Et) = 0.88. Generally, the Mayo-Lewis equation holds between the molar ratio of the monomers [the molar ratio of VAc to Et (D = Dvac / Det)], the molar ratio of the monomer units contained in the resulting VAc / Et copolymer [the molar ratio of VAc units to Et units (F = Fvac / Fet)], and the copolymerization reactivity ratio of the monomers, so (D) can be expressed by the following equation: D=(F-1+((1-F)^2+3.6256F)^0.5) / 2.06

[0114] The total amount of VAc and Et (Yvac+et) (mol) in the copolymerization of VAc and Et is calculated by the following formula using the amount of VAc (Yvac) (mol) in the copolymerization and the molar ratio D. (Yvac+et)=(Yvac)+(Yvac) / D

[0115] [Methyl acrylate monomer unit content in vinyl acetate block copolymer (U)] The content (U) (mol %) of methyl acrylate monomer units in the vinyl acetate block copolymer was determined by the following method. 1 H-NMR measurements were performed. The integral value (4.8 ppm) of the peak derived from the methine proton (-CH2CH(OCOCH3)-) of the vinyl acetate monomer unit was defined as T, and the integral value (3.6 ppm) of the peak derived from the side chain proton (-CH2CH(COOCH3)-) of the methyl acrylate monomer unit was defined as S. The content (U) (mol%) of acrylate monomer units in the vinyl acetate block copolymer was calculated using the following formula. Furthermore, the content (U) and the number-average molecular weight (Mn) of each polymer block were used to determine the content of MA units in the copolymer block containing VAc units and MA units. (U) (mol%) = (S / 3) / (S / 3 + T) × 100

[0116] [Content of Et monomer units in vinyl acetate block copolymers (R)] The content (R) (mol %) of Et monomer units in the vinyl acetate block copolymer was determined by the following method. 1 H-NMR measurement was performed. The methine proton (-CH2C H The integral value (4.8 ppm) of the peak derived from (OCOCH3)-) was taken as T, and the methylene proton (-C H 2CH(OCOCH3)-) and the main chain protons of the Et units (-C H 2C H The integrated value (1.0-1.8 ppm) of the peak derived from VAc (2-) was defined as Q, and the content (R) (mol%) of Et units in the vinyl acetate block copolymer was calculated using the following formula: In addition, the content (R) and the number average molecular weight (Mn) of each polymer block were used to determine the content of Et units in the copolymer block containing VAc units and Et units. (R) (mol%) = (Q-2T) / 4 / ((Q-2T) / 4+T) × 100

[0117] [Acrylic acid monomer unit content in vinyl acetate block copolymer (O)] The content (O) (mol %) of acrylic acid monomer units in the vinyl acetate block copolymer was determined by the following method. 1 H-NMR measurement was performed. The methine proton (-CH2C H The integral value (4.8 ppm) of the peak derived from the side chain protons of the acrylic acid monomer unit (-CH2CH(COO H The integrated value (12.2 ppm) of the peak derived from )-) was defined as P, and the content (O) (mol %) of acrylic acid monomer units in the vinyl acetate block copolymer was calculated using the following formula: In addition, the content (U) and the number average molecular weight (Mn) of each polymer block were used to determine the content of AA units in the copolymer block containing VAc units and AA units. (O) (mol%) = P / (P + T) × 100

[0118] [Content of N,N-dimethylacrylamide monomer units in vinyl acetate block copolymers (M)] The content (M) (mol %) of N,N-dimethylacrylamide units in the vinyl acetate block copolymer was determined by the following method. 1 H-NMR measurement was performed. The methine proton (-CH2C H The integral value (4.8 ppm) of the peak derived from the side chain protons of the N,N-dimethylacrylamide monomer unit (-CHCH(CONH(C H 3) The integrated value (3.0 ppm) of the peak derived from 2-) was defined as N,N-dimethylacrylamide monomer unit content (M) (mol %) in the vinyl acetate block copolymer was calculated using the following formula: In addition, the content (M) and the number average molecular weight (Mn) of each polymer block were used to determine the content of DMAA units in the copolymer block containing VAc units and DMAA units. (M) (mol%) = (N / 6) / ((N / 6) + T) × 100

[0119] [Maleic anhydride monomer unit content in vinyl acetate block copolymers (J)] The content (J) (mol %) of maleic anhydride units in the vinyl acetate block copolymer was determined by the following method. 1 H-NMR measurement was performed. The methine proton (-CH2C H The integral value (5.1 ppm) of the peak derived from the maleic anhydride monomer unit (-C H C H The content (J) (mol%) of maleic anhydride monomer units in the vinyl acetate block copolymer was calculated using the integral value (3.0 ppm) of the peak derived from (COCO)- as L using the following formula: In addition, the content (J) and the number average molecular weight (Mn) of each polymer block were used to determine the content of MAn units in the copolymer block containing VAc units and MAn units. (J) (mol%) = (L / 2) / ((L / 2) + K) × 100

[0120] [Content (W) of terminal structural units represented by formula (V) or (VI) in the polymer] The content (W) (mol %) of the terminal structural unit represented by formula (V) or (VI) in the polymer was calculated as follows. As an example, the content of methyl cinnamate added to the polyvinyl acetate terminal was quantified. Polyvinyl acetate was dissolved in methanol and repeatedly reprecipitated with hexane to remove methyl cinnamate not added to the polyvinyl acetate terminal. The recovered polyvinyl acetate was dried in a vacuum dryer at 40°C for 24 hours, and the content of the resulting polyvinyl acetate was 1 H-NMR measurement was performed. The methine proton (-CH2C H The integral value (4.8 ppm) H of the peak derived from (OCOCH3)-) and the integral value G of all peaks detected in the range of 7.1 to 7.5 ppm derived from the aromatic rings of methyl cinnamate were calculated. When calculating the integral value from 7.1 to 7.5 ppm, if a slope was observed in the baseline, the slope was taken into account when calculating the area value of each peak. The content (W) was calculated from [(G / number of hydrogen atoms bonded to aromatic rings) / H] using the integral value H and the integral value G divided by the number of hydrogen atoms bonded to aromatic rings (G / number of hydrogen atoms bonded to aromatic rings). (W) (mol%) = (G / 5) / H × 100

[0121] [Molar ratio (F) of the terminal structure represented by formula (V) or (VI) relative to the number of polymer chains] The molar ratio (F) of the terminal structure represented by formula (V) or (VI) relative to the number of polymer chains was calculated as follows: Using the content (W) of the terminal structural unit represented by formula (V) or (VI) in the polymer, Mn, and the molecular weight of the monomer unit, the molar ratio (F) was calculated from [W / (Mn / molecular weight of monomer unit × 100)]. A molar ratio (F) of 1 indicates that a structural unit represented by formula (V) or (VI) has been introduced at one end of all polymer chains, and the closer to 1 the ratio, the better the controllability. (F)=W / (Mn / 86×100)

[0122] [Example 1] <Polymerization process> A reactor equipped with a stirrer, reflux condenser, and radical generator inlet was charged with 900 parts by weight of VAc, followed by introduction of nitrogen into the reactor to replace the atmosphere with an inert gas. A preparation vessel was charged with 100 parts by weight of VAc, 0.22 parts by weight of cinnamic acid as the organic compound (A), and 0.45 parts by weight of V-70 as the radical generator (B). After dissolution, nitrogen was introduced into the reactor to replace the atmosphere with an inert gas. The solution in the preparation vessel was then added to the reactor, heated to a reactor temperature of 50°C, and stirred. Sampling was performed as needed to confirm the progress of polymerization based on the solids concentration. At a VAc conversion rate of 3.9% by weight, the number average molecular weight (Mn) was 86,800, the theoretical number average molecular weight (theoretical Mn) was 26,800, and the ratio (Mn / theoretical Mn) was 3.2. At a VAc conversion of 9.5% by mass, the number average molecular weight (Mn) was 132,800, the theoretical number average molecular weight (Mn / Mn) was 65,300, and the ratio (Mn / Mn) was 2.0. At a VAc conversion of 12.7% by mass, the number average molecular weight (Mn) was 166,900, the theoretical number average molecular weight (Mn / Mn) was 87,100, and the ratio (Mn / Mn) was 1.9. When the VAc conversion reached 22% by mass, 1.31 parts by mass of 1,1-DPEt was added as a polymerization terminator. At this point, the number average molecular weight (Mn) was 226,400, the theoretical number average molecular weight (Mn / Mn) was 149,300, the ratio (Mn / Mn) was 1.5, and the molecular weight distribution (Mw / Mn) was 2.57. Unreacted VAc was distilled off from the solution under reduced pressure to recover polyvinyl acetate, which was then dried in a vacuum dryer at 40°C for 24 hours to obtain polyvinyl acetate. Details of the polymerization process are shown in Table 1. Figure 1 is a plot of number average molecular weight (Mn) against VAc conversion. The ratio (Mn / theoretical Mn) of the number average molecular weight (Mn) (measured value) to the theoretical number average molecular weight (theoretical Mn) of the polymer, determined from Figure 1 when the VAc conversion was 5.0%, was 3.0.

[0123] [Example 2] <Polymerization process> A polymerization reaction was carried out in the same manner as in Example 1, except that 0.24 parts by mass of methyl cinnamate was added as organic compound (A) and the reactor was heated and stirred to an internal temperature of 50°C. After the addition of the polymerization terminator, the reactor was connected to a vacuum line, and unreacted VAc was azeotropically removed while adding methanol to obtain a methanol solution of polyvinyl acetate. Details are shown in Table 1.

[0124] <Saponification process> Next, the concentration of the methanol solution was adjusted to 1834 parts by weight of methanol per 100 parts by weight of the resulting polyvinyl acetate in a similar reactor as above, and the mixture was heated and stirred until the internal temperature reached 40°C using a heated water bath. 66.4 parts by weight of a methanol solution of sodium hydroxide (14% by weight, 9.3 parts by weight of sodium hydroxide) was added. A saponification reaction was carried out at 65°C for 1 hour using the resulting 5% by weight polyvinyl acetate methanol solution. After dewatering, phenolphthalein solution was added to the washing liquid (methanol), and the mixture was washed with methanol until no alkaline reaction was observed, thereby removing the sodium hydroxide and sodium acetate. The solid obtained after centrifugation was dried in a vacuum dryer at 40°C for 24 hours to obtain white polyvinyl alcohol. The degree of saponification was 99.9%.

[0125] [Example 3] <Polymerization process> Polyvinyl acetate was obtained by carrying out a polymerization reaction in the same manner as in Example 1, except that 0.15 parts by mass of methyl cinnamate as the organic compound (A) and 0.29 parts by mass of V-70 as the radical generator (B) were added, the reactor was heated to an internal temperature of 45°C, and 0.84 parts by mass of 1,1-DPEt was added as a terminator. Details are shown in Table 1.

[0126] [Example 4] <Polymerization process> Polyvinyl acetate was obtained by carrying out a polymerization reaction in the same manner as in Example 1, except that 0.09 parts by mass of methyl cinnamate as the organic compound (A) and 0.18 parts by mass of V-70 as the radical generator (B) were added, the reactor was heated to an internal temperature of 40°C, and 0.52 parts by mass of 1,1-DPEt was added as a terminator. Details are shown in Table 1.

[0127] [Example 5] <Polymerization process> Polyvinyl acetate was obtained by carrying out a polymerization reaction in the same manner as in Example 1, except that 1.88 parts by mass of methyl cinnamate was added as the organic compound (A) and 35.81 parts by mass of V-70 as the radical generator (B), the reactor was heated to an internal temperature of 45°C, and 10.47 parts by mass of 1,1-DPEt was added as a terminator. Details are shown in Table 1.

[0128] [Example 6] <Polymerization process> A polymerization reaction was carried out in the same manner as in Example 1, except that 0.24 parts by mass of methyl cinnamate was added as the organic compound (A) and 0.22 parts by mass of V-70 was added as the radical generator (B), to obtain polyvinyl acetate. Details are shown in Table 1.

[0129] [Example 7] <Polymerization process> A polymerization reaction was carried out in the same manner as in Example 1, except that a total of 1,000 parts by mass of N-vinylpyrrolidone was added as the monomer (Y), 0.18 parts by mass of methyl cinnamate was added as the organic compound (A), and 0.35 parts by mass of V-70 was added as the radical generator (B), to obtain polyvinylpyrrolidone.

[0130] [Example 8] <Polymerization process> A polymerization reaction was carried out in the same manner as in Example 1, except that 0.24 parts by mass of methyl cinnamate was added as the organic compound (A), the reactor was heated to an internal temperature of 65°C, and 0.81 parts by mass of sorbic acid was added as a terminator, thereby obtaining polyvinyl acetate. Details are shown in Table 1.

[0131] [Example 9] <Polymerization process> A polymerization reaction was carried out in the same manner as in Example 1, except that 0.24 parts by mass of methyl cinnamate was added as the organic compound (A) and 25.0 parts of methanol as the solvent, and the contents were heated and stirred so that the internal temperature of the reactor reached 60°C, to obtain polyvinyl acetate. Details are shown in Table 1.

[0132] [Example 10] <Polymerization process> Polystyrene was obtained by carrying out a polymerization reaction in the same manner as in Example 1, except that 1,000 parts by mass of styrene was added as the monomer (Y), 0.18 parts by mass of trans-benzalacetone was added as the organic compound (A), 0.37 parts by mass of V-70 was added as the radical generator (B), and 0.81 parts by mass of sorbic acid was added as a terminator. Details are shown in Table 1.

[0133] [Example 11] <Polymerization process> A polymerization reaction was carried out in the same manner as in Example 1, except that 0.21 parts by mass of trans-benzalacetone was added as the organic compound (A) and the reactor was heated to an internal temperature of 60° C., to obtain polyvinyl acetate. Details are shown in Table 1.

[0134] [Example 12] <Polymerization process> A polymerization reaction was carried out in the same manner as in Example 1, except that 0.21 parts by mass of coumarin was added as the organic compound (A) and the contents were heated and stirred so that the internal temperature of the reactor reached 45° C., to obtain polyvinyl acetate. Details are shown in Table 1.

[0135] [Example 13] <Polymerization process> A polymerization reaction was carried out in the same manner as in Example 1, except that 0.19 parts by mass of cinnamic alcohol was added as the organic compound (A) and the reactor was heated so that the internal temperature reached 60° C. Details are shown in Table 1.

[0136] [Example 14] <Polymerization process> A polymerization reaction was carried out in the same manner as in Example 1, except that 0.28 parts by mass of β-ionone was added as the organic compound (A) and the reactor was heated to an internal temperature of 30° C., to obtain polyvinyl acetate. Details are shown in Table 1.

[0137] [Comparative Example 1] <Polymerization process> Polyvinyl acetate was obtained by carrying out a polymerization reaction in the same manner as in Example 1, except that 0.22 parts by mass of 4-phenyl-2-butanone was added instead of the organic compound (A) and the reactor was heated to an internal temperature of 60° C. Details are shown in Table 2.

[0138] Comparative Example 2 <Polymerization process> Polyvinyl acetate was obtained by carrying out a polymerization reaction in the same manner as in Example 1, except that the organic compound (A) was not added and the reactor was heated so that the internal temperature reached 30° C. Details are shown in Table 2.

[0139] Comparative Example 3 <Polymerization process> A polymerization reaction was carried out in the same manner as in Example 1, except that 0.24 parts by mass of methyl cinnamate was added as the organic compound (A) and 0.09 parts by mass of V-70 was added as the radical generator (B). Since the polymerization had hardly progressed even after 5 hours, the polymerization was discontinued. Details are shown in Table 2.

[0140] [Example 15] <Polymerization process> 900 parts by mass of VAc was added to a reactor equipped with a stirrer, a reflux condenser, and an inlet for adding the radical generator (B), and then nitrogen was introduced into the reactor to replace the atmosphere with an inert gas. 100 parts by mass of VAc, 0.24 parts by mass of methyl cinnamate as the organic compound (A), and 0.45 parts by mass of V-70 as the radical generator (B) were added to a preparation vessel and dissolved. After dissolving, nitrogen was introduced and replaced with an inert gas. The solution in the preparation vessel was added to the reactor, and the reactor was heated and stirred to an internal temperature of 45°C. Sampling was performed as needed to check the progress of polymerization based on the solids concentration. When the VAc conversion reached 8.4% by mass, 30.00 parts by mass of MA was added. The number-average molecular weight (Mn) of the polymer at a conversion rate of 8.4% by mass was 150,700. The calculated molar ratio (Y / A) was 8240. Heating and stirring was continued, and the progress of polymerization was checked based on the solids concentration. GPC measurement and analysis of the sampled polymer were also performed. 1H-NMR measurements were performed, and when the total conversion of VAc and MA reached 17.4% by mass, 1.31 parts by mass of 1,1-DPEt was added as a polymerization terminator. The number-average molecular weight (Mn) at this point was 233,700. The reactor was connected to a vacuum line, and unreacted VAc was azeotropically removed while adding methanol, yielding a methanol solution of a vinyl acetate block copolymer. Details are shown in Table 2. The content of MA units in the resulting vinyl acetate block copolymer was 9 mol %, and the content of MA units in the copolymer block containing VAc and MA units was 25 mol %.

[0141] <Saponification process> Next, the concentration of the methanol solution was adjusted to 1834 parts by mass of methanol per 100 parts by mass of the obtained vinyl acetate block copolymer in the same reactor as above, and the water bath was heated and stirred until the internal temperature reached 40°C. 66.4 parts by mass of a methanol solution of sodium hydroxide (concentration 14% by mass, 9.3 parts by mass of sodium hydroxide) was added. A saponification reaction was carried out at 65°C for 1 hour using the vinyl acetate block copolymer solution with a concentration of 5% by mass thus prepared. 46.5 parts by mass of sodium hydroxide, 2000 parts by mass of dehydrated methanol, and 210 parts by mass of ion-exchanged water were added to the saponified product obtained after deliquoring, and heating was continued for another 1 hour at 65°C. After deliquoring, phenolphthalein solution was added to the washing liquid (methanol), and the mixture was washed with methanol until no alkaline reaction was observed, and the sodium hydroxide and sodium acetate were removed. The solid obtained by centrifugal dehydration was dried in a vacuum dryer at 40°C for 24 hours to obtain a white vinyl alcohol-based block copolymer (a diblock copolymer of a vinyl alcohol-based polymer block and a copolymer block containing vinyl alcohol-based monomer units and acrylic acid-based monomer units). The degree of saponification was 99.9%. Details are shown in Table 2.

[0142] [Example 16] <Polymerization process> 900 parts by mass of VAc was added to a reactor equipped with a stirrer, a reflux condenser, and an inlet for the radical generator (B), and nitrogen was then introduced into the reactor to flush with an inert gas. 100 parts by mass of VAc, 0.24 parts by mass of methyl cinnamate as the organic compound (A), and 0.45 parts by mass of V-70 as the radical generator (B) were added to a preparation vessel and dissolved. After dissolving, nitrogen was introduced and flushed with an inert gas. The solution in the preparation vessel was added to the reactor, and the reactor was heated and stirred to an internal temperature of 45°C. Sampling was performed as needed to check the progress of polymerization based on the solids concentration. When the VAc conversion reached 10.2% by mass, the Et pressure was adjusted to 9 bar. The calculated Y / A molar ratio was 9120. The number average molecular weight (Mn) of the polymer at a conversion of 10.2% by mass was 176,600. The mixture was then heated and stirred, and the progress of the polymerization was confirmed from the solid concentration. The sampled polymer was subjected to GPC measurement and 1 H-NMR measurements were performed, and when the total conversion of VAc and Et reached 18.3% by mass, 1.31 parts by mass of 1,1-DPEt was added as a polymerization terminator. The number-average molecular weight (Mn) at this point was 203,600. The reactor was connected to a vacuum line, and unreacted VAc was azeotropically removed while adding methanol, yielding a methanol solution of a vinyl acetate block copolymer. Details are shown in Table 2. The content of Et units in the resulting vinyl acetate block copolymer was 2 mol %, and the content of Et units in the copolymer block containing VAc units and Et units was 12 mol %.

[0143] <Saponification process> Next, a saponification reaction was carried out in the same manner as in Example 2 to obtain a white vinyl alcohol-based block copolymer (a diblock copolymer of vinyl alcohol-based polymer block and copolymer block containing vinyl alcohol-based monomer units and Et units). Details are shown in Table 2.

[0144] [Example 17] <Polymerization process> A reactor equipped with a stirrer, reflux condenser, and radical generator (B) inlet was charged with 900 parts by mass of VAc and 180 parts by mass of MA, and then nitrogen was introduced into the reactor to replace the atmosphere with an inert gas. 100 parts by mass of VAc, 0.63 parts by mass of methyl cinnamate as the organic compound (A), and 3.58 parts by mass of V-70 as the radical generator (B) were added to a preparation vessel and dissolved. After dissolving, nitrogen was introduced and the atmosphere was replaced with an inert gas. The calculated molar ratio (Y / A) was 3000. The solution in the preparation vessel was added to the reactor, and the reactor was heated and stirred to an internal temperature of 40°C. Sampling was performed as needed to check the progress of polymerization based on the solids concentration. When the total conversion rate of VAc and MA reached 25.0% by mass, it was determined that MA had been completely consumed (the molar ratio (acrylic acid ester / vinyl ester) was less than 0.00001). 1 The polymerization was confirmed by H-NMR. The number average molecular weight (Mn) at this time was 109,400. Immediately thereafter, 4000.00 parts by mass of VAc was added. The total conversion of VAc and MA at this time was 5.8% by mass, and the calculated molar ratio (Y / A) was 13,000. Heating and stirring was continued, and the progress of polymerization was confirmed from the solid concentration, and a sample of the polymer was subjected to GPC measurement and 1 H-NMR measurements were performed, and when the total conversion of VAc and MA reached 20.3% by mass, 3.49 parts by mass of 1,1-DPEt was added as a polymerization terminator. The number-average molecular weight (Mn) at this point was 195,500. The reactor was connected to a vacuum line, and unreacted VAc was azeotropically removed while adding methanol, yielding a methanol solution of a vinyl acetate block copolymer. Details are shown in Table 2. The content of MA units in the resulting vinyl acetate block copolymer was 19 mol%, and the content of MA units in the copolymer block containing VAc and MA units was 63 mol%.

[0145] <Saponification process> Next, a saponification reaction was carried out in the same manner as in Example 2 to obtain a white vinyl alcohol-based block copolymer, the details of which are shown in Table 2.

[0146] [Example 18] <Polymerization process> 900 parts by mass of VAc was added to a reactor equipped with a stirrer, a reflux condenser, and an inlet for adding the radical generator (B), and nitrogen was then introduced into the reactor to replace the atmosphere with an inert gas. 100 parts by mass of VAc, 0.24 parts by mass of methyl cinnamate as the organic compound (A), and 1.34 parts by mass of V-70 as the radical generator (B) were added to a preparation vessel and dissolved. After dissolving, nitrogen was introduced and replaced with an inert gas. The solution in the preparation vessel was added to the reactor, and the reactor was heated and stirred to an internal temperature of 40°C. Sampling was performed as needed to check the progress of polymerization based on the solids concentration. When the VAc conversion reached 9.7% by mass, 83.72 parts by mass of AA was added. The number-average molecular weight (Mn) of the polymer at a conversion of 9.7% by mass was 104,900. The calculated molar ratio (Y / A) was 8100. Heating and stirring was continued, and the progress of polymerization was checked based on the solids concentration. Samples were then taken, and GPC analysis and characterization of the sampled polymer were performed. 1 H-NMR measurements were performed, and when the total conversion of VAc and AA reached 16.2% by mass, 1.31 parts by mass of 1,1-DPEt was added as a polymerization terminator. The number-average molecular weight (Mn) at this point was 144,400. The reactor was connected to a vacuum line, and unreacted VAc was azeotropically removed while adding methanol, yielding a methanol solution of a vinyl acetate block copolymer. Details are shown in Table 2. The content of AA units in the resulting vinyl acetate block copolymer was 8 mol %, and the content of AA units in the copolymer block containing VAc and AA units was 20 mol %.

[0147] <Saponification process> Next, a saponification reaction was carried out in the same manner as in Example 2 to obtain a white vinyl alcohol-based block copolymer, the details of which are shown in Table 2.

[0148] [Example 19] <Polymerization process> 900 parts by mass of VAc was added to a reactor equipped with a stirrer, a reflux condenser, and an inlet for adding the radical generator (B), and nitrogen was then introduced into the reactor to replace the atmosphere with an inert gas. 100 parts by mass of VAc, 0.24 parts by mass of methyl cinnamate as the organic compound (A), and 1.34 parts by mass of V-70 as the radical generator (B) were added to a preparation vessel and dissolved. After dissolving, nitrogen was introduced and replaced with an inert gas. The solution in the preparation vessel was added to the reactor, and the reactor was heated and stirred to an internal temperature of 40°C. Sampling was performed as needed to check the progress of polymerization based on the solids concentration. When the VAc conversion reached 8.4% by mass, 115.10 parts by mass of DMAA was added. The number-average molecular weight (Mn) of the polymer at a conversion rate of 8.4% by mass was 114,600. The calculated molar ratio (Y / A) was 8100. Heating and stirring was continued, and the progress of polymerization was checked based on the solids concentration. GPC measurement and analysis of the sampled polymer were also performed. 1 H-NMR measurements revealed that the total conversion of VAc and DMAA reached 19.9% ​​by mass. 1.31 parts by mass of 1,1-DPEt was added as a polymerization terminator. The number-average molecular weight (Mn) at this point was 145,000. The reactor was connected to a vacuum line, and unreacted VAc was azeotropically removed while adding methanol, yielding a methanol solution of a vinyl acetate block copolymer. Details are shown in Table 2. The content of DMAA units in the resulting vinyl acetate block copolymer was 6 mol %, and the content of DMAA units in the copolymer block containing VAc and DMAA units was 20 mol %.

[0149] <Saponification process> Next, a saponification reaction was carried out in the same manner as in Example 2 to obtain a white vinyl alcohol-based block copolymer, the details of which are shown in Table 2.

[0150] [Example 20] <Polymerization process> 900 parts by mass of VAc was added to a reactor equipped with a stirrer, a reflux condenser, and an inlet for adding the radical generator (B), and nitrogen was then introduced into the reactor to replace the atmosphere with an inert gas. 100 parts by mass of VAc, 0.24 parts by mass of methyl cinnamate as the organic compound (A), and 1.34 parts by mass of V-70 as the radical generator (B) were added to a preparation vessel and dissolved. After dissolving, nitrogen was introduced and replaced with an inert gas. The solution in the preparation vessel was added to the reactor, and the reactor was heated and stirred to an internal temperature of 40°C. Sampling was performed as needed to check the progress of polymerization based on the solids concentration. When the VAc conversion reached 7.4% by mass, 113.95 parts by mass of MAn was added. The number-average molecular weight (Mn) of the polymer at a conversion of 7.4% by mass was 74,400. The calculated molar ratio (Y / A) was 8100. Heating and stirring was continued, and the progress of polymerization was checked based on the solids concentration. GPC measurement and analysis of the sampled polymer were also performed. 1 H-NMR measurements were performed, and when the total conversion of VAc and MAn reached 18.1% by mass, 1.31 parts by mass of 1,1-DPEt was added as a polymerization terminator. The number-average molecular weight (Mn) at this point was 100,800. The reactor was connected to a vacuum line, and unreacted VAc was azeotropically removed while adding methanol, yielding a methanol solution of a vinyl acetate block copolymer. Details are shown in Table 2. The content of MAn units in the resulting vinyl acetate block copolymer was 8 mol %, and the content of MAn units in the copolymer block containing VAc units and MAn units was 13 mol %.

[0151] <Saponification process> Next, a saponification reaction was carried out in the same manner as in Example 2 to obtain a white vinyl alcohol-based block copolymer, the details of which are shown in Table 2.

[0152] [Example 21] <Polymerization process> In the polymerization of Example 1, a sample was taken immediately before the addition of the polymerization terminator, and the polymer was recovered by reprecipitation after being dropped into hexane. The polymer was dissolved in methanol, dropped again into hexane, and dried to obtain polyvinyl acetate. The content (W) of trans-cinnamic acid-derived structures at the polyvinyl acetate terminals was 0.036 mol %. The molar ratio (F) of the trans-cinnamic acid-derived structures to the amount of polyvinyl acetate terminals was 0.95. Details are shown in Table 2.

[0153] [Example 22] <Polymerization process> In the polymerization of Example 5, a sample was taken immediately before the addition of the polymerization terminator, and the polymer was recovered by reprecipitation after being dropped into hexane. The polymer was dissolved in methanol, dropped again into hexane, and dried to obtain polyvinyl acetate. The content (W) of methyl cinnamate-derived structures at the polyvinyl acetate terminals was 0.48 mol%, and the molar ratio (F) of the methyl cinnamate-derived structures to the amount of polyvinyl acetate terminals was 0.97.

[0154] [Table 1]

[0155] [Table 2]

[0156] In Examples 1 to 20, the ratio (Mn / theoretical Mn) at the beginning of polymerization was 10.0 or less, and Mn increased with increasing conversion, confirming that polymerization proceeded in a controlled manner.

[0157] In Examples 1 to 11 and 15 to 20, the ratio (Mn / theoretical Mn) at the beginning of polymerization was 5.0 or less, and Mn increased with increasing conversion, confirming that polymerization proceeded in a more favorable and controlled manner.

[0158] It was confirmed that the polymers obtained in Examples 21 and 22 had a structure represented by formula (V) or (VI) at their terminals. Since the molar ratio (F) of the structure represented by formula (V) or (VI) to the amount of polymer terminals was close to 1, it was confirmed that the structure represented by formula (V) or (VI) was quantitatively contained at the polymer terminals.

[0159] In Comparative Example 1, the value of Mn / theoretical Mn at the beginning of polymerization exceeded 10.0, confirming poor polymerization controllability.

[0160] In Comparative Example 2, Mn did not increase with an increase in conversion rate, and it was therefore confirmed that polymerization controllability was poor.

[0161] In Comparative Example 3, the polymerization proceeded extremely slowly, and it was confirmed that the productivity was poor.

Claims

1. The method includes a polymerization step of obtaining a polymer by performing controlled radical polymerization of a monomer (Y) in the presence of an organic compound (A) represented by the following formula (I) and a radical generator (B), A method for producing a polymer, wherein the molar ratio of (B) to (A) (B / A) is 0.5 to 20, and the polymerization temperature is 0 to 80°C. 【Chemistry 1】 [In formula (I), R １ is an alkenyl group or an aryl group, and R ２ is a group represented by the following formula (II) or (III), and R １ and R ２ may be linked to each other to form a ring. 【Chemistry 2】 [In formula (II), R ３ represents a hydrogen atom, a halogen atom, an alkyl group, an aryl group, an alkenyl group, an alkoxy group, an amino group, a nitro group, a cyano group, an acetyl group, a trifluoromethyl group, or a hydroxyl group, and * represents a bond. 【Transformation 3】 [In formula (III), R ３ has the same meaning as in formula (II), and * indicates a bond.

2. The method includes a polymerization step of obtaining a polymer by conducting controlled radical polymerization of a monomer (Y) in the presence of an organic compound (A) represented by the following formula (IV) and a radical generator (B), A method for producing a polymer, wherein the molar ratio of (B) to (A) (B / A) is 0.5 to 20. 【Chemistry 4】 [In formula (IV), R 3 represents a hydrogen atom, a halogen atom, an alkyl group, an aryl group, an alkenyl group, an alkoxy group, an amino group, a nitro group, a cyano group, an acetyl group, a trifluoromethyl group, or a hydroxyl group, and R 4 represents a hydrogen atom, an alkyl group, an alkoxy group, or a hydroxyl group.]

3. The method includes a polymerization step of obtaining a polymer by performing controlled radical polymerization of a monomer (Y) in the presence of an organic compound (A) represented by the following formula (I) and a radical generator (B), A method for producing a polymer, wherein the molar ratio of (B) to (A) (B / A) is 0.5 to 20. 【Transformation 5】 [In formula (I), R １ is an alkenyl group or an aryl group, and R ２ is a group represented by the following formula (II) or (III), and R １ and R ２ may be linked to each other to form a ring. 【Transformation 6】 [In formula (II), R ３ is a methoxy group or a hydroxyl group, and * indicates a bond. 【Transformation 7】 [In formula (III), R ３ has the same meaning as in formula (II), and * indicates a bond.

4. The method includes a polymerization step of obtaining a vinyl ester polymer by controlled radical polymerization of a vinyl ester in the presence of an organic compound (A) represented by the following formula (I) and a radical generator (B), and a saponification step of obtaining a vinyl alcohol polymer by saponifying the obtained vinyl ester polymer: A method for producing a polymer, wherein the molar ratio of (B) to (A) (B / A) is 0.5 to 20. 【Transformation 8】 [In formula (I), R １ is an alkenyl group or an aryl group, and R ２ is a group represented by the following formula (II) or (III), and R １ and R ２ may be linked to each other to form a ring. 【Chemistry 9】 [In formula (II), R ３ represents a hydrogen atom, a halogen atom, an alkyl group, an aryl group, an alkenyl group, an alkoxy group, an amino group, a nitro group, a cyano group, an acetyl group, a trifluoromethyl group, or a hydroxyl group, and * represents a bond. 【Chemistry 10】 [In formula (III), R ３ has the same meaning as in formula (II), and * indicates a bond.

5. The method includes a polymerization step of sequentially carrying out controlled radical polymerization of a vinyl ester and controlled radical polymerization of a vinyl ester and a monomer other than the vinyl ester in the presence of an organic compound (A) represented by the following formula (I) and a radical generator (B), thereby obtaining a vinyl ester-based block copolymer, A method for producing a polymer, wherein the molar ratio of (B) to (A) (B / A) is 0.5 to 20. 【Chemistry 11】 [In formula (I), R １ is an alkenyl group or an aryl group, and R ２ is a group represented by the following formula (II) or (III), and R １ and R ２ may be linked to each other to form a ring. 【Chemistry 12】 [In formula (II), R ３ represents a hydrogen atom, a halogen atom, an alkyl group, an aryl group, an alkenyl group, an alkoxy group, an amino group, a nitro group, a cyano group, an acetyl group, a trifluoromethyl group, or a hydroxyl group, and * represents a bond. 【Chemistry 13】 [In formula (III), R ３ has the same meaning as in formula (II), and * indicates a bond.

6. R １ The method for producing a polymer according to any one of claims 1, 3, 4 and 5, wherein is an aryl group.

7. The method for producing a polymer according to any one of claims 1, 3, 4, 5 and 6, wherein the organic compound (A) is an E-form.

8. R ４ The method for producing a polymer according to claim 2, wherein is a hydrogen atom.

9. 4. The method for producing a polymer according to claim 1, wherein the molar ratio (Y / A) of the monomer (Y) to the organic compound (A) is 300 to 30,000.

10. The method for producing a polymer according to any one of claims 1 to 3, wherein the monomer (Y) comprises an olefin, a vinyl ester, acrylic acid, an acrylic acid ester, an acrylamide-based monomer, a styrene-based monomer, an N-vinylamide-based monomer, or a dicarboxylic acid-based monomer.

11. 6. The method for producing a polymer according to claim 5, comprising: a polymerization step of sequentially carrying out controlled radical polymerization of a vinyl ester and controlled radical polymerization of a vinyl ester and a monomer other than a vinyl ester in the presence of an organic compound (A) and a radical generator (B) to obtain a vinyl ester-based block copolymer; and a saponification step of saponifying the obtained vinyl ester-based block copolymer to obtain a vinyl alcohol-based block copolymer.

12. The present invention relates to an organic compound (A) represented by the following formula (I), a radical generator (B), and a monomer (Y), A composition for radical polymerization, wherein the molar ratio (B / A) of (B) to (A) is 0.5 to 20, the molar ratio (Y / A) of the monomer (Y) to the organic compound (A) is 300 to 30,000, and the monomer (Y) contains a vinyl ester or N-vinylpyrrolidone. 【Chemistry 14】 [In formula (I), R １ is an alkenyl group or an aryl group, and R ２ is a group represented by the following formula (II) or (III), and R １ and R ２ may be linked to each other to form a ring. 【Chemistry 15】 [In formula (II), R ３ represents a hydrogen atom, a halogen atom, an alkyl group, an aryl group, an alkenyl group, an alkoxy group, an amino group, a nitro group, a cyano group, an acetyl group, a trifluoromethyl group, or a hydroxyl group, and * represents a bond. 【Chemistry 16】 [In formula (III), R ３ has the same meaning as in formula (II), and * indicates a bond.

13. The composition for radical polymerization according to claim 12, wherein the monomer (Y) contains a vinyl ester.

14. A radical polymerization inhibitor comprising an organic compound (A) represented by the following formula (IV): 【Chemistry 17】 [In formula (IV), R 3 represents a hydrogen atom, a halogen atom, an alkyl group, an aryl group, an alkenyl group, an alkoxy group, an amino group, a nitro group, a cyano group, an acetyl group, a trifluoromethyl group, or a hydroxyl group, and R 4 represents a hydrogen atom, an alkyl group, an alkoxy group, or a hydroxyl group.]

15. A polymer containing a vinyl ester unit or an N-vinylpyrrolidone unit and having a terminal structure represented by the following formula (V) or (VI): [Chemistry 18] [In formula (V), R １ is an alkenyl group or an aryl group, and R ２ is a group represented by the following formula (II) or (III), and R １ and R ２ may be linked to each other to form a ring. * indicates a bond.] 【Chemistry 19】 [In formula (VI), R １ and R ２ has the same meaning as in formula (V), and * indicates a bond. 【Chemistry 20】 [In formula (II), R ３ represents a hydrogen atom, a halogen atom, an alkyl group, an aryl group, an alkenyl group, an alkoxy group, an amino group, a nitro group, a cyano group, an acetyl group, a trifluoromethyl group, or a hydroxyl group, and * represents a bond. 【Chemistry 21】 [In formula (III), R ３ has the same meaning as in formula (II), and * indicates a bond.

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