JP2010077112A - Methylene lactone monomer and method of preserving the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a methylene lactone monomer which exhibits controlled decrease in the rate of polymerization and polymerization property and can be suitably used as a raw material of an industrial polymer. <P>SOLUTION: The methylene lactone monomer is expressed by general formula (1), wherein R<SP>1</SP>, R<SP>2</SP>, R<SP>3</SP>and R<SP>4</SP>identically or differently denote a hydrogen atom or a monovalent organic group. The methylene lactone monomer is a solution in which dissolved oxygen is 0.02 mg/L or more and which makes a polymerization inhibitor exist together, wherein polymerization inhibitor concentration expressed as the ratio of the amount of the polymerization inhibitor which substantially acts on the methylene lactone monomer to the mass of the methylene lactone monomer is 0.1 mass% or less. <P>COPYRIGHT: (C)2010,JPO&amp;INPIT

Description

The present invention relates to a methylene lactone monomer and a storage method thereof. More specifically, the present invention relates to a methylene lactone monomer that can be suitably used in industrial production, use, storage, transportation, and the like of a methylene lactone monomer and a storage method thereof.

A methylene lactone monomer having an exomethylene group and a lactone ring structure is known as a physiologically active skeleton, and is expected as an intermediate for medicines and agricultural chemicals such as antitumor agents and antiviral agents. It is expected to be applied as a monomer for producing a polymer having properties such as properties, UV curability, adhesiveness, and transparency. Polymers obtained from such monomers include raw materials for manufacturing various chemical products such as electronic information materials, battery materials, optical materials, resist materials, liquid crystal materials, refrigerant materials, paints, adhesives, detergent builders, and medical and agricultural chemicals. It may be applicable to raw materials. Thus, the methylene lactone monomer is a useful compound in the fields of chemistry, medicine and agricultural chemicals.

Generally, as a method for producing a methylene lactone monomer, a basic condition or a synthetic route using a metal catalyst is known. For example, a method of reacting γ-butyrolactone and ethyl formate in the presence of a basic compound, and subsequently reacting the resulting compound with formaldehyde (for example, see Patent Document 1), acrylic acid under a metal catalyst such as palladium. A method of reacting an alkene compound with an alkene compound (for example, see Patent Document 2 and Non-Patent Document 1), and a method of reacting an α-halogenated methylacrylic acid with a carbonyl compound in the presence of zinc (for example, see Patent Document 3). ), A method of reacting γ-butyrolactone with formaldehyde in the presence of a metal oxide catalyst, a zeolite catalyst or the like (see, for example, Patent Document 4), a method of reacting γ-butyrolactone with formaldehyde in the presence of a basic catalyst. (For example, refer to Patent Document 5). Further, a compound obtained by reacting a γ-butyrolactone compound having a substituent obtained by catalytic reduction of alkylidene succinic anhydride or alkylmaleic anhydride with an oxalic acid ester in the presence of a basic compound. (For example, see Patent Document 6), and a method for reacting a γ-butyrolactone compound having a substituent obtained from levulinic acid with formaldehyde in the presence of a basic catalyst (for example, see Patent Document 7). Etc.) and the like. After these synthesis steps, impurities such as unreacted raw materials are removed by a purification step. For example, 2,6-di-tert-butyl-4-methylphenol (BHT) is added to α-methylene-γ-butyrolactone to prevent the polymerization reaction from occurring during storage. Such as those obtained by adding hydroquinone to α-methylene-γ-valerolactone (see, for example, Non-Patent Document 2).

US Pat. No. 5,166,357 International Publication No. 2008/023823 Japanese Patent Laid-Open No. 9-12632 Japanese Patent Laid-Open No. 10-120672 US Pat. No. 6,232,474 JP 2007-217388 A US Patent Publication No. 2006/0100447

J. et al. Chem. Soc. , Chem. Commun. 1994, pp. 2589-2590. TCI ORGANIC CHEMICALS, 2006-2007, pages 1401, 1404 Chemical Dictionary (Tokyo Chemical Doujin), pages 654-655

A polymer produced from a methylene lactone monomer is expected to be used in various industrial fields. However, a methylene lactone monomer has a polymerization rate when used as a raw material for a polymerization reaction. It has been found that the polymer has a property that the polymerization property is lowered, such as a decrease in the induction period until the polymerization is started, and the like. When producing a polymer in an industrial production process, it is necessary to produce the polymer with high efficiency from the viewpoint of production cost, etc. It is a major problem to be solved when considering the industrial use of methylene lactone monomers.
The present invention has been made in view of the above-described situation, and suppresses a decrease in polymerizability such as a decrease in the polymerization rate of a methylene lactone monomer and a long induction period until the start of polymerization, and an industrial polymer. It aims at providing the methylene lactone monomer which can be used suitably as a manufacturing raw material of this.

As a result of various studies on methylene lactone monomers having specific physical properties derived from a structure having an exomethylene group and a lactone ring structure, the present inventors used the methylene lactone monomer as a raw material for the polymerization reaction. In some cases, it has been found that the polymerization rate may decrease, the polymerization property may decrease such as the induction period until the polymerization starts, or the odor may be generated. Here, surprisingly, molecular oxygen (also simply referred to as oxygen) is “when performing radical polymerization, molecular oxygen (also simply referred to as oxygen) reacts with radicals generated from initiators and monomers. Although it is known that the polymerization is inhibited because the compound cannot be initiated by polymerization (Non-Patent Document 3), the methylene lactone monomer does not contain oxygen in the presence of oxygen. When stored in the presence of coexistence, it has been found that the polymerization rate decreases and the induction period until the start of polymerization is prolonged, and methylene lactone monomer is handled as a general monomer known so far. It was found that it was necessary to find a device for handling different from the above. Therefore, in the methylene lactone monomer, the dissolved oxygen amount is set to 0.02 mg / L or more, and the amount of the polymerization inhibitor that substantially acts on the methylene lactone monomer is based on the mass of the methylene lactone monomer. When the polymerization inhibitor is allowed to coexist so that the concentration of the polymerization inhibitor expressed as a ratio is 0.1% by mass or less, the decrease in the polymerizability of the methylene lactone monomer is suppressed, and it is suitably used as a raw material for the polymer. It was found to be a monomer that can be used. In addition, the methylene lactone monomer may be colored during storage or polymerization, or may be polymerized during storage or odor may be generated, so that the amount of dissolved oxygen becomes a specific value or more as described above, In addition, the coexistence of a polymerization inhibitor at a specific concentration or less is sufficient to suppress the decrease in polymerizability, and the coloring, secondary polymerization of methylene lactone monomer, and odor generation are sufficient. It was found that a methylene lactone monomer suitable for storage and use as a raw material for polymerization reaction can be provided.
In addition, in normal polymerizable monomers other than methylene lactone monomers, when used in the normal use amount range used as a polymerization inhibitor, it exerts a polymerization inhibition effect that enhances storage stability during storage, and polymerization during polymerization In the methylene lactone monomer which is a special monomer as in the present invention, it is usually used as a polymerization inhibitor. It has been clarified by the present inventors that even if it is used within the usage amount range, it may cause a problem during polymerization. In the present invention, the amount of dissolved oxygen is increased, and the presence of a polymerization inhibitor in a small specific range increases storage stability during storage. The present inventors have found that the polymerization rate of the polymer is not a major obstacle, and the polymerization inhibitor concentration, which is set low, can suppress a decrease in the polymerization rate peculiar to the methylene lactone monomer.
Furthermore, the present inventors have the effect of preventing a decrease in polymerizability by using one or more of thioether, phosphite, or phenolic compounds as a polymerization inhibitor. It has also been found that various effects are exhibited more remarkably, and among these, by using a phenolic compound having a specific structure, a further remarkable effect of preventing a decrease in polymerizability, etc. is also found. The inventors have arrived at the present invention by conceiving that the problem can be solved brilliantly. In particular, in a methylene lactone monomer, when used as a polymer raw material, the polymerization rate decreases, the induction period until the start of polymerization becomes long, etc. In the present invention, the present invention has found that the amount of dissolved oxygen and the type and concentration of the polymerization inhibitor are factors that affect the decrease in polymerizability. This has great significance in finding the amount of dissolved oxygen and the type and concentration of the polymerization inhibitor.

That is, the present invention provides the following general formula (1);

(Wherein R ¹ , R ² , R ³ and R ⁴ are the same or different and represent a hydrogen atom or a monovalent organic group), The methylene lactone monomer is a solution in which the dissolved oxygen amount is 0.02 mg / L or more and a polymerization inhibitor coexists, and the amount of methylene lactone that is a polymerization inhibitor amount that substantially acts on the methylene lactone monomer. It is a methylene lactone monomer having a polymerization inhibitor concentration expressed as a ratio to the mass of the body of 0.1% by mass or less.
The present invention is described in detail below.

The methylene lactone monomer of the present invention is a solution having a dissolved oxygen content of 0.02 mg / L or more, but the dissolved oxygen content is preferably 0.05 mg / L or more. More preferably, it is 0.1 mg / L or more. More preferably, it is 0.25 mg / L or more, particularly preferably 0.5 mg / L or more, and most preferably 1.0 mg / L or more. When the amount of dissolved oxygen is increased, the effect of suppressing the decrease in polymerizability of the methylene lactone monomer and the effect of suppressing the occurrence of coloring and storage and the generation of odor are more prominently exhibited. Moreover, it is preferable that the amount of dissolved oxygen is 2000 mg / L or less. In usual methods for increasing dissolved oxygen such as bubbling and pressurization, it may be difficult to increase the amount of dissolved oxygen to more than 2000 mg / L, or an expensive container or device may be required. On the other hand, if the amount of dissolved oxygen is more than 2000 mg / L, the methylene lactone monomer may be deteriorated. Also, even in storage under the same conditions, there may be differences in the amount of dissolved oxygen depending on the lot, but there is no particular problem if the amount of dissolved oxygen in the solution at the time of storage is 0.02 mg / L or more. .
The amount of dissolved oxygen in the methylene lactone monomer solution can be measured with an oxygen meter or the like. In the present invention, the term “colored” means that the maximum absorbance in the region of 400 to 600 nm is obtained when UV-VIS spectrum analysis of a solution of methylene lactone monomer is performed and the baseline of the spectrum is adjusted to zero. , 0.005 or more. If it is 0.005 or more, it can be determined visually that it is colored.

The methylene lactone monomer of the present invention is a solution in which a polymerization inhibitor coexists, and is expressed as a ratio of the amount of the polymerization inhibitor that substantially acts on the methylene lactone monomer to the mass of the methylene lactone monomer. The polymerization inhibitor concentration is 0.1% by mass or less. That is, the following formula:
Polymerization inhibitor concentration (mass%) = [{Polymerization inhibitor (g) × (methylene lactone monomer (g) / methylene lactone monomer solution (g))} / methylene lactone monomer (g) ] × 100
The polymerization inhibitor concentration determined in (1) is 0.1% by mass or less. When the methylene lactone monomer has a dissolved oxygen amount of 0.02 mg / L or more and contains a polymerization inhibitor at such a concentration, the methylene lactone monomer is used as a raw material for the polymerization reaction. Thus, stable polymerizability is exhibited, and it becomes possible to provide a methylene lactone monomer suitable for various uses. In addition, polymerization during storage or transportation is sufficiently suppressed, and it becomes possible to handle it stably and safely without coloring. These polymerization inhibitors coexist with a dissolved oxygen amount of 0.02 mg / L or more with respect to a methylene lactone monomer having specific physical properties derived from the specific structure represented by the general formula (1). In this case, a remarkable effect is exhibited, and by using these polymerization inhibitors, in addition to the effect of suppressing the decrease in polymerizability, coloring and odor suppression of the methylene lactone monomer during storage and transportation, Effects such as suppression of polymerization and suppression of coloring when used as a raw material for the polymerization reaction will be exhibited. On the other hand, when the concentration of the polymerization inhibitor is higher than 0.1% by mass, the polymerization reaction may not sufficiently proceed when such a methylene lactone monomer is subjected to the polymerization reaction. It is important to set the concentration within the optimum range.
As described above, the polymerization inhibitor exhibits a polymerization inhibitory effect on the methylene lactone monomer at a specific concentration. For example, for acrylic acid structurally similar to the methylene lactone monomer, The polymerization inhibitor does not exhibit a polymerization inhibitory effect at the above-mentioned specific concentration. The reason for this is that the driving force of the polymerization of the methylene lactone monomer is elimination of the distortion of the ring structure, and a factor different from the driving force of the polymerization of other polymerizable monomers such as acrylic acid is considered. It is done. Therefore, the significance of including the polymerization inhibitor at the above concentration is peculiar to the methylene lactone monomer.

As said polymerization inhibitor density | concentration, More preferably, it is 0.000001-0.095 mass%, More preferably, it is 0.00001-0.085 mass%. Most preferably, it is 0.00005-0.08 mass%. Even when the methylene lactone monomer is dissolved in the solvent, the polymerization inhibitor concentration is defined as the concentration relative to the methylene lactone monomer.
In the present invention, there is an optimum concentration range for more effectively exerting the effects of the present invention for each type of polymerization inhibitor used, and the concentration range is set according to the type of polymerization inhibitor. It is more preferable. For example, as will be described later, when p-methoxyphenol is used as the polymerization inhibitor, the concentration is preferably 0.00001 to 0.08% by mass, more preferably 0.0001 to 0. 0.05% by mass. More preferably, it is 0.0001-0.02 mass%, Most preferably, it is 0.0001-0.01 mass%. When 2,6-di-t-butyl-4-methylphenol is used, the concentration is preferably 0.0001 to 0.095% by mass, more preferably 0.0005 to 0. 0.09% by mass. More preferably, it is 0.001-0.07 mass%, Most preferably, it is 0.001-0.05 mass%.

The polymerization inhibitor is (a) the polymerization inhibitor is accurately weighed and added in accordance with the volume of the methylene lactone monomer, and (b) the polymerization inhibitor is excessively added to the volume of the methylene lactone monomer. After the addition, the excess is removed using activated carbon or the like. (C) After adding a polymerization inhibitor to the volume of the methylene lactone monomer, the methylene lactone monomer and the solvent are distilled off. The predetermined concentration can be obtained by any one of the above methods or in combination.

The methylene lactone monomer of the present invention is a solution having a dissolved oxygen amount of 0.02 mg / L or more. However, when the methylene lactone monomer is stored, the dissolved oxygen amount is 0.02 mg / L or more even during storage. It is preferable that the image is stored while maintaining this state. By being stored in such a state, the methylene lactone monomer can be kept in a state in which the decrease in polymerizability is suppressed and can be suitably used as a raw material for the polymer. It becomes possible to maintain a high quality state without coloring, polymerization, and odor generation.

The methylene lactone monomer generally exists as a solid or liquid at room temperature and normal pressure. Therefore, the methylene lactone monomer of the present invention may be one that preserves the methylene lactone monomer in the liquid state as it is, or dissolves the methylene lactone monomer in the solid or liquid state in the solvent. Or may be stored in a mixed state. The solvent may be a compound that does not react with the methylene lactone monomer under the above conditions, and is water, hydrocarbon, aromatic hydrocarbon, alcohol, ketone, ester, ether, nitrile, halogenated hydrocarbon, amide. , Sulfoxide and the like are preferable. For example, water, pentane, hexane, cyclohexane, heptane, octane, cyclooctane, benzene, toluene, xylene, trimethylbenzene, methanol, ethanol, propanol, isopropanol, butanol, t-butanol, hexanol, cyclohexanol, ethylene glycol, polyethylene glycol , Acetone, ethyl methyl ketone, methyl butyl ketone, methyl isobutyl ketone, ethyl acetate, butyl acetate, methyl benzoate, dimethyl phthalate, γ-butyrolactone, dimethoxyethane, dioxane, tetrahydrofuran, polyethylene glycol ether, acetonitrile, methylene chloride, chloroform , Dichloroethane, N, N-dimethylformamide, N, N-dimethylacetamide, N-methylpyrrole Emissions, dimethyl sulfoxide, carbon tetrachloride and the like. Among them, water, hexane, cyclohexane, octane, benzene, toluene, xylene, trimethylbenzene, methanol, ethanol, propanol, isopropanol, butanol, ethylene glycol, polyethylene glycol, acetone, ethyl methyl ketone, methyl isobutyl ketone, ethyl acetate, butyl acetate , Dimethoxyethane, dioxane, tetrahydrofuran, methylene chloride, chloroform, dichloroethane, N, N-dimethylformamide, N, N-dimethylacetamide, N-methylpyrrolidone, dimethylsulfoxide and the like are more preferable. Only one kind of the solvent may be used, or two or more kinds may be appropriately mixed and used. When a solvent is used, the dissolved oxygen amount of the methylene lactone monomer solution dissolved in the solvent may be 0.02 mg / L or more.

When the methylene lactone monomer of the present invention is dissolved and mixed in a solvent, the mass concentration of the methylene lactone monomer in the solvent is preferably 10% or more and 99% or less. More preferably, they are 20% or more and 90% or less, More preferably, they are 40% or more and 70% or less.

The temperature of the methylene lactone monomer of the present invention is preferably 100 ° C. or lower. More preferably, it is 85 degrees C or less, More preferably, it is 60 degrees C or less. The lower limit of the temperature is not particularly limited, but is preferably −50 ° C. or higher. More preferably, it is −25 ° C. or higher. When the temperature of the methylene lactone monomer is at such a temperature, not only a decrease in polymerizability is suppressed, but also the effect of suppressing the coloring and storage, and the generation of odors are more prominent. Can be used immediately in the reaction.

Moreover, when storing a methylene lactone monomer in a container, it is preferable that the pressure in a container is 0.01-20 atm. More preferably, it is 0.1-10 atm. When the methylene lactone monomer is stored under such a pressure, it can be used immediately for various uses such as a raw material of a polymer without causing deterioration of polymerizability or coloring during storage.

The gas phase portion in contact with the methylene lactone monomer preferably has an oxygen concentration of 0.001% or more. More preferably, it is 0.005% or more, and still more preferably 0.01% or more. If the oxygen concentration in the gas phase is 0.001% or less, the dissolved oxygen concentration gradually decreases during storage even if the oxygen concentration in the methylene lactone monomer solution was initially 0.02 mg / L. If it is less than 0.02 mg / L, the methylene lactone monomer may be reduced in polymerizability, and may be colored, polymerized during storage, or odor.

In the methylene lactone monomer, the dissolved oxygen amount is set to 0.02 mg / L or more, such as a method of bubbling air, oxygen, oxygen-containing gas, etc., or stirring or standing in the gas phase part. Examples thereof include a method of introducing air, oxygen, oxygen-containing gas, and the like, and a method of introducing and pressurizing air, oxygen, oxygen-containing gas or the like into the gas phase portion at a normal pressure or higher while stirring or standing.

The polymerization inhibitor used in the methylene lactone monomer of the present invention is not particularly limited as long as it is a compound that prevents radical polymerization reaction. For example, thioether, phosphite, phenol, stable free radical, amine Examples thereof include compounds such as systems, organic ligand-containing metal systems, and inorganic oxide systems, and one or more of these can be used. Among the above polymerization inhibitors, in order to sufficiently realize the suppression of coloring of the methylene lactone monomer and the stable polymerization of the compound, it is possible to use at least one of thioether, phosphite and phenol compounds. preferable. The polymerization inhibitor is preferably mainly composed of a thioether, phosphite or phenol compound. That is, in the polymerization inhibitor, the total amount of thioether, phosphite, and phenolic compounds is preferably 50% by mass or more in 100% by mass of the polymerization inhibitor. More preferably, it is 60 mass% or more, More preferably, it is 70 mass% or more, Especially preferably, it is 80 mass% or more, Most preferably, it is 90 mass% or more.

It is one of the preferred embodiments of the present invention that the polymerization inhibitor is at least one compound selected from the group consisting of thioether-based, phosphite-based, and phenol-based compounds. As the polymerization inhibitor, one or more compounds belonging to the same system may be used, or one or more compounds belonging to different systems may be used.

The thioether-based polymerization inhibitor is a compound having a thioether skeleton and capable of capturing radicals. For example, dilauryl-3,3′-thiodipropionate, dimyristyl-3,3′-thiodipropionate, distearyl-3,3′-thiodipropionate, pentaerythritol tetrakis (3-laurylthiopropionate ), Ditridecyl-3,3′-thiodipropionate, 2-mercaptobenzimidazole, ditridecyl-3,3′-thiodipropionate, 1,3,5-tris-β-stearylthiopropionyloxyethyl isocyanurate, 3,3'-thiobispropionic acid didodecyl ester, 3,3'-thiobispropionic acid dioctadecyl ester, and the like.

The phosphite polymerization inhibitor is a compound having a phosphorus atom and capable of trapping radicals. For example, triphenyl phosphite, diethyl 3,5-di-t-butyl-4-hydroxybenzylphosphonate, distearyl pentaerythritol diphosphite, bis (2,6-di-t-butylphenyl) pentaerythritol diphos Phyto, 2,2′-methylenebis (4,6-di-t-butylphenyl) 2-ethylhexyl phosphite, tetra (tridecyl) -4,4′-butylidenebis (3-methyl-6-t-butylphenol) diphosphite, Distearyl pentaerythritol diphosphite, bis (2,6-di-t-butyl-4-methylphenyl) pentaerythritol diphosphite, tris (mono, dinonylphenyl) phosphite, tridecyl phosphite, tris (2 , 4-Di-t-butylphenyl) phosphie Etc. The.

The phenol-based polymerization inhibitor is a compound having a structure in which at least one hydroxyl group is bonded to an aromatic ring and capable of scavenging radicals. For example, hydroquinone, p-methoxyphenol, 2,5-di-t-butylhydroquinone, 2,5-di-t-amylhydroquinone, 2-t-butylhydroquinone, 2,2′-methylene-bis (4-methyl -6-tert-butylphenol), 2,2'-methylene-bis (4-ethyl-6-tert-butylphenol), tris (3,5-di-tert-butyl-4-hydroxybenzyl) isocyanurate, 1, 1,3-tris (2-methyl-4-hydroxy-5-tert-butylphenyl) butane (topanol), 4,4′-butylidenebis (3-methyl-6-tert-butylphenol), n-octadecyl-3- (3 ′, 5′-di-t-butyl-4′-hydroxyphenyl) propionate, tetrakis [methylene-3- (3 ′, 5′-di-t-butyl-4 ′ Hydroxyphenyl) propionate] methane, 3,9-bis [2- [3- (3-tert-butyl-4-hydroxy-5-methylphenyl) -propionyloxy] -1,1-dimethylethyl] -2,4 , 8,10-tetraoxaspiro [5,5] undecane, 1,3,5-trimethyl-2,4,6-tris (3,3-di-t-butyl-4-hydroxybenzyl) benzene, 2, 6-di-t-butyl-4-methylphenol, 2-t-butyl-4-methylphenol, 2,4,6-tri-t-butylphenol, 2,6-di-t-butyl-2,4- Xylenol, N, N′-hexamethylenebis (3,5-di-tert-butyl-4-hydroxy-hydrocinnamimide), 1,3,5-trimethyl-2,4,6-tris (3,5 -Di-t-butyl- -Hydroxybenzyl) benzene, 2- (2'-hydroxy-3'-t-butyl-5'-methylphenyl) -5-chlorobenzotriazole, 2- (2'-hydroxy-5'-methylphenyl) benzotriazole 2,2′-methylene bis [4- (1,1,3,3-tetramethylbutyl) -6- (2N-benzotriazol-2-yl) phenol], 2- (2′-hydroxy-5 ′ -T-octylphenyl) benzotriazole and the like.

The stable free radical polymerization inhibitor is a compound to which a free radical that can exist stably for a long time is bonded. Examples of the compound to which a free radical that can exist stably for a long time is bonded include, for example, a compound having a structure in which unpaired electrons are on oxygen with a large electronegativity and can be delocalized, or unpaired electrons. A compound having a sterically bulky group in the vicinity and reducing the reactivity of unpaired electrons is preferred. Examples of such compounds include carbinoxyl compounds, N-oxyl compounds, [{(CH ₃ ) ₃ Si}] ₂ CH ₃ Ge, [{(CH ₃ ) ₃ Si} ₂ CH] ₃ Sn, and the like. Can be mentioned.

The amine polymerization inhibitor is a compound having a structure in which one or two or more hydrocarbon groups are bonded to a nitrogen atom. Examples of the amine polymerization inhibitor include phenothiazine, alkylated diphenylamine, tetrakis (2,2,6,6-tetramethyl-4-piperidyl) -1,2,3,4-butanetetracarboxylate and the like.

The organic ligand-containing metal-based polymerization inhibitor is a metal complex having a structure in which an organic compound having an unshared electron pair becomes a ligand and is bonded to a metal element. The metal element only needs to be capable of coordinating with the lone pair of the organic compound, and examples of such a metal element include copper and aluminum. Among these, copper is preferable, and examples thereof include copper dimethyldithiocarbamate, copper diethyldithiocarbamate, and copper dibutyldithiocarbamate.
Examples of the inorganic oxide polymerization inhibitor include copper oxide.

In the methylene lactone monomer of the present invention, a polymerization inhibitor belonging to any of thioether, phosphite, and phenol, which is a stable free radical, amine, organic ligand-containing metal, or inorganic Those that can be said to belong to any of the oxides are classified into thioethers, phosphites, and phenols. For example, 2- (2'-hydroxy-5'-methylphenyl) benzotriazole having a phenolic moiety and an amine moiety belongs to the phenolic group.

As described above, the polymerization inhibitor used in the methylene lactone monomer of the present invention is at least one compound selected from the group consisting of thioether, phosphite, and phenol compounds. Preferable phenolic polymerization inhibitors are those having a structure in which at least one substituent other than a hydroxyl group is bonded to an aromatic ring. That is, the polymerization inhibitor used in the methylene lactone monomer of the present invention is a thioether-based, phosphite-based, or phenol-based compound having a structure in which at least one substituent other than a hydroxyl group is bonded to an aromatic ring. More preferably, it is at least one compound selected from the group consisting of compounds having More preferably, it is a phenol-based compound having a structure in which at least one substituent other than a hydroxyl group is bonded to an aromatic ring.

Examples of the substituent other than the hydroxyl group in the phenolic compound include an alkyl group having 1 to 18 carbon atoms, an alkoxyl group having 1 to 10 carbon atoms, an ester group-containing group having 1 to 10 carbon atoms, and one or more carbon atoms. An amide group-containing group having 10 or less, an aromatic ring-containing group having 6 to 20 carbon atoms, a benzotriazole group-containing group having 6 to 20 carbon atoms, or a benzotriazole group having a substituent on an aromatic ring having 6 to 20 carbon atoms Containing groups are preferred. More preferably, they are an alkyl group having 1 to 12 carbon atoms, an alkoxyl group having 1 to 8 carbon atoms, an ester group-containing group having 1 to 8 carbon atoms, and an aromatic ring-containing group having 6 to 12 carbon atoms.

As the polymerization inhibitor used in the methylene lactone monomer of the present invention, among those described above, p-methoxyphenol, topanol, 2,6-di-t-butyl-4-methylphenol, pentaerythritol tetrakis (3-lauryl) Thiopropionate), triphenyl phosphite and hydroquinone are preferred. More preferably, p-methoxyphenol, topanol, 2,6-di-t-butyl-4-methylphenol, pentaerythritol tetrakis (3-laurylthiopropionate), triphenyl phosphite, P-methoxyphenol and topanol are preferred.

The methylene lactone monomer in the present invention has the following general formula (1):

(Wherein R ¹ , R ² , R ³ and R ⁴ are the same or different and each represents a hydrogen atom or a monovalent organic group). The methylene lactone monomer may be colored even at room temperature and refrigerated storage, and the polymerization rate may decrease, or the polymerization may decrease, such as the induction period until the polymerization starts. These defects can be effectively suppressed by specifying the amount of dissolved oxygen such as the methylene lactone monomer of the present invention and making the solution coexist with a polymerization inhibitor having a specific concentration.
Further, when R ¹ , R ² , R ³ and R ⁴ are as described below, the effect of the methylene lactone monomer of the present invention is more remarkably exhibited.

R ¹ , R ² , R ³ and R ⁴ include a hydrogen atom, a hydroxyl group, a linear saturated alkyl group having 1 to 60 carbon atoms, a branched saturated alkyl group, an alicyclic saturated alkyl group, and an aromatic group-containing group. Straight chain unsaturated alkyl group, branched unsaturated alkyl group or alicyclic unsaturated alkyl group, or ester group having 1 to 60 carbon atoms, nitrile group, carboxylic acid group, ether group, hydroxyl group, halogen group, isonitrile Group, cyanate group, isocyanate group, thiocyanate group, isothiocyanate group, sulfide group, disulfide group, sulfoxide group, sulfone group, nitro group, nitroso group, sulfonic acid group, carbonyl group (for example, ketone or aldehyde), amino Group, amine oxide group, nitrone group, amide group, azide group, acetal group, azo group, azoxy group, azine group, imi group Group, an imido group, an enamine group, an enamide group, ortho ester group, a diazo group, a diazonium group, a ketal group, an onium salt, a heterocyclic compound, heteroaromatic compound is preferably an atomic group having a hetero element, and the like. More preferably, a hydrogen atom, a hydroxyl group, a linear saturated alkyl group having 1 to 30 carbon atoms, a branched saturated alkyl group, an alicyclic saturated alkyl group, an aromatic group-containing group, a linear unsaturated alkyl group, a branched unsaturated group. Alkyl groups, alicyclic unsaturated alkyl groups, and ester groups having 1 to 30 carbon atoms, nitrile groups, carboxylic acid groups, ether groups, hydroxyl groups, sulfonic acid groups, carbonyl groups, amino groups, amide groups, onium salts Is an atomic group having More preferably, a hydrogen atom, a hydroxyl group, a linear saturated alkyl group having 1 to 18 carbon atoms, a branched saturated alkyl group, an alicyclic saturated alkyl group, an aromatic group-containing group, and an ester having 1 to 18 carbon atoms. An atomic group having a group, a carboxylic acid group, an ether group, a hydroxyl group, a sulfonic acid group, a carbonyl group, and an amino group. More preferably, they are a hydrogen atom, a hydroxyl group, or a hydrocarbon group having 1 to 12 carbon atoms which may have a substituent. Among these, a hydrogen atom, a hydroxyl group, or an alkyl group having 1 to 8 carbon atoms is more preferable. Particularly preferred are a hydrogen atom, a methyl group, an ethyl group, a propyl group, a butyl group, a pentyl group, and a hexyl group. Most preferably, they are a hydrogen atom, a methyl group, an ethyl group, a propyl group, or a butyl group. In addition, at least one of R ³ and R ⁴ is preferably a methyl group, an ethyl group, a propyl group, a butyl group, a pentyl group, or a hexyl group. More preferably, at least one of R ³ and R ⁴ is a methyl group, an ethyl group, a propyl group, or a butyl group. R ¹ , R ² , R ³ and R ⁴ may be bonded to form a ring structure.

The methylene lactone monomer of the present invention may contain a methylene lactone monomer, a polymerization inhibitor, oxygen, and other components other than the solvent in the solution, but the methylene lactone monomer is the main component. Preferably, the content ratio of the methylene lactone monomer is 90% or more with respect to 100% of the total mass of the methylene lactone monomer and the other components other than the polymerization inhibitor, oxygen, and the solvent. Is preferred. More preferably, it is 92% or more, and still more preferably 94% or more. Examples of the other components other than the methylene lactone monomer, the polymerization inhibitor, oxygen, and the solvent include, for example, an internal alkene formed by isomerization of the double bond at the exo site of the methylene lactone monomer.

The methylene lactone monomer is, for example, a method of reacting lactone with ethyl formate in the presence of a basic compound, and subsequently reacting the obtained compound with formaldehyde, lactone and oxalate ester in the presence of a basic compound. And then reacting the resulting compound with formaldehyde, reacting acrylic acid with an alkene compound in the presence of a metal catalyst such as palladium, and α-halogenated methylacrylic acid and a carbonyl compound in the presence of zinc. And a method of reacting lactone with formaldehyde in the presence of a metal oxide or a basic catalyst. Like the methylene lactone monomer of the present invention, the polymerization inhibitor concentration (polymerization inhibitor concentration expressed as a ratio of the amount of polymerization inhibitor substantially acting on the methylene lactone monomer to the mass of the methylene lactone monomer) However, 0.1% by mass or less) and a method of suppressing the decrease in polymerizability by coexisting the dissolved oxygen amount of 0.02 mg / L or more to stabilize the polymerizability, and to suppress coloring and the like The methylene lactone monomer produced by such a production method can be suitably used.

Specific examples of particularly preferable compounds as the methylene lactone monomer of the present invention include α-methylene-γ-butyrolactone, α-methylene-γ-valerolactone, γ-ethyl-α-methylene-γ-butyrolactone, γ-propyl. -Α-methylene-γ-butyrolactone, γ-butyl-α-methylene-γ-butyrolactone, γ-pentyl-α-methylene-γ-butyrolactone, γ-hexyl-α-methylene-γ-butyrolactone, γ, γ-dimethyl -Α-methylene-γ-butyrolactone, γ-phenyl-α-methylene-γ-butyrolactone, β-methyl-α-methylene-γ-butyrolactone, β-ethyl-α-methylene-γ-butyrolactone, β-propyl-α -Methylene-γ-butyrolactone, β-butyl-α-methylene-γ-butyrolactone, β-pentyl-α-methylene-γ- Butyrolactone, β-hexyl-α-methylene-γ-butyrolactone, β, β-dimethyl-α-methylene-γ-butyrolactone, β-phenyl-α-methylene-γ-butyrolactone, β-methyl-γ-methyl-α- Examples include methylene-γ-butyrolactone and γ-acetoxy-α-methylene-γ-butyrolactone. Among these, α-methylene-γ-butyrolactone, α-methylene-γ-valerolactone, γ-ethyl-α-methylene-γ-butyrolactone, γ-butyl-α-methylene-γ-butyrolactone, γ-hexyl-α Most preferred are -methylene-γ-butyrolactone, γ-phenyl-α-methylene-γ-butyrolactone, β-methyl-α-methylene-γ-butyrolactone, β, β-dimethyl-α-methylene-γ-butyrolactone. .

As described above, when the methylene lactone monomer of the present invention is used as a raw material for a polymer, the polymerization rate is sufficiently lowered, and the polymerization is sufficiently reduced such that the induction period until the start of polymerization is prolonged. In addition to being suppressed, coloring, polymerization, and generation of odor are sufficiently suppressed, and therefore, it can be suitably used as a raw material for the polymer. Such a methylene lactone monomer for a raw material of a methylene lactone polymer characterized by comprising the methylene lactone monomer of the present invention is also one aspect of the present invention.

The present invention also provides the following general formula (1):

(Wherein R ¹ , R ² , R ³ and R ⁴ are the same or different and each represents a hydrogen atom or a monovalent organic group). In the above storage method, the methylene lactone monomer is stored as a solution in which the dissolved oxygen amount is 0.02 mg / L or more and the polymerization inhibitor coexists, and the polymerization substantially acts on the methylene lactone monomer. It is also a method for storing a methylene lactone monomer in which the polymerization inhibitor concentration expressed as a ratio of the amount of the inhibitor to the mass of the methylene lactone monomer is 0.1% by mass or less.
As described above, the methylene lactone monomer has a dissolved oxygen amount of 0.02 mg / L or more, and the amount of the polymerization inhibitor that substantially acts on the methylene lactone monomer with respect to the mass of the methylene lactone monomer. In addition to suppressing a decrease in polymerizability by coexisting a polymerization inhibitor so that the polymerization inhibitor concentration expressed as a ratio is 0.1% by mass or less, coloring and polymerization during storage, and generation of odor Since it can be sufficiently suppressed, the methylene lactone monomer is stored as a solution in which the dissolved oxygen amount is 0.02 mg / L or more and the polymerization inhibitor coexists, and substantially acts on the methylene lactone monomer. Preserving the polymerization inhibitor concentration expressed as a ratio of the amount of the polymerization inhibitor to the mass of the methylene lactone monomer as 0.1% by mass or less is a preferable method for storing the methylene lactone monomer. It is.

The method for storing a methylene lactone monomer of the present invention may be a method of storing a methylene lactone monomer having a dissolved oxygen content of 0.02 mg / L or more as it is, and a dissolved oxygen content of 0.02 mg / L. Any methylene lactone monomer that is less than or equal to 0.02 mg / L or more may be stored. As a method for setting the dissolved oxygen amount of the methylene lactone monomer having a dissolved oxygen amount of less than 0.02 mg / L to 0.02 mg / L or more, air, oxygen, a gas containing oxygen, or the like is bubbled. Method, a method of introducing air, oxygen, oxygen-containing gas or the like into the gas phase portion while stirring or standing, a gas containing air, oxygen, oxygen or the like in the gas phase portion while stirring or standing Examples include a method of introducing and pressurizing at a pressure higher than normal pressure.
Even when the methylene lactone monomer is stored at a dissolved oxygen amount of 0.02 mg / L or more, the amount of methylene lactone is less when stored under nitrogen than when stored under air. The weight average molecular weight of the methylene lactone polymer obtained by polymerizing the polymer may be slightly reduced. This is considered to be due to some chain transfer effect acting when a methylene lactone monomer stored under nitrogen is subjected to a polymerization reaction.

The method for storing the methylene lactone monomer is stored as a solution in which a polymerization inhibitor coexists, and is expressed as a ratio of the amount of the polymerization inhibitor that substantially acts on the methylene lactone monomer to the mass of the methylene lactone monomer. The concentration of the polymerization inhibitor is 0.1% by mass or less, and the methylene lactone monomer is stored. The concentration of the polymerization inhibitor is more preferably 0.000001 to 0.095% by mass. More preferably, it is 0.00001-0.085 mass%. Most preferably, it is 0.00005-0.08 mass%.
In addition, in the same way as the methylene lactone monomer of the present invention described above, also in the method of storing the methylene lactone monomer of the present invention, the effect of the present invention is more effectively exhibited for each type of polymerization inhibitor used. It is more preferable to set the concentration range according to the type of the polymerization inhibitor. For example, when p-methoxyphenol is used as a polymerization inhibitor, the concentration is preferably 0.00001 to 0.08 mass%, more preferably 0.0001 to 0.05 mass%. is there. More preferably, it is 0.0001-0.02 mass%, Most preferably, it is 0.0001-0.01 mass%. When 2,6-di-t-butyl-4-methylphenol is used, the concentration is preferably 0.0001 to 0.095% by mass, more preferably 0.0005 to 0. 0.09% by mass. More preferably, it is 0.001-0.07 mass%, Most preferably, it is 0.001-0.05 mass%.
Even when the methylene lactone monomer is dissolved in the solvent, the polymerization inhibitor concentration is defined as the concentration relative to the methylene lactone monomer.

The methylene lactone monomer is preferably stored at a temperature of −50 to 80 ° C. When the methylene lactone monomer is stored at such a temperature, it is possible to effectively suppress the decrease in polymerizability, and more effective coloring, polymerization, and odor generation of the methylene lactone monomer. Can be suppressed. More preferably, it is -40-75 degreeC, More preferably, it is -25-70 degreeC. Most preferably, it is -15-60 degreeC.

As the polymerization inhibitor used in the method for preserving the methylene lactone monomer of the present invention, one or two or more similar to those used for the methylene lactone monomer of the present invention described above can be used. Among these, it is preferable to use at least one compound selected from the group consisting of thioether-based, phosphite-based, and phenol-based compounds. By using these polymerization inhibitors, in addition to being able to prevent a decrease in polymerizability over a long period of time, coloring and polymerization of the methylene lactone monomer can be sufficiently suppressed. It is possible to maintain a higher quality for a long time. More preferable as the polymerization inhibitor is at least one compound selected from the group consisting of phenolic compounds having a structure in which at least one substituent other than a hydroxyl group is bonded to an aromatic ring. More preferably, it is a phenol-based compound having a structure in which at least one substituent other than a hydroxyl group is bonded to an aromatic ring. By using a phenolic compound having a structure in which at least one substituent other than a hydroxyl group is bonded to an aromatic ring, the methylenelactone monomer can be maintained at a higher quality.
As the substituent other than the hydroxyl group in the phenol-based compound, the same ones as described above are preferable.

Specifically, the polymerization inhibitor used in the method for storing a methylene lactone monomer of the present invention is preferably the same as that used for the methylene lactone monomer of the present invention described above, and p-methoxyphenol. , Topanol, 2,6-di-t-butyl-4-methylphenol, pentaerythritol tetrakis (3-laurylthiopropionate), triphenyl phosphite and hydroquinone Is preferred. More preferably, p-methoxyphenol, topanol, 2,6-di-t-butyl-4-methylphenol, pentaerythritol tetrakis (3-laurylthiopropionate), triphenyl phosphite, P-methoxyphenol and topanol are preferred.

As described above, the methylene lactone monomer of the present invention and the methylene lactone monomer stored by the storage method of the methylene lactone monomer of the present invention have a long induction period until the polymerization rate decreases and the polymerization starts. In addition to the suppression of the decrease in polymerizability such as the coloring, since the coloring is sufficiently suppressed, electronic information materials, optical materials, resist materials, liquid crystal materials, refrigerant materials, battery materials, etc. Can be suitably used as a raw material for a polymer used in various industrial fields including the above, whereby a polymer in which coloring is sufficiently suppressed can be efficiently obtained.
Such a method for producing a methylene lactone polymer produced using the methylene lactone monomer of the present invention or the methylene lactone monomer after the method for preserving the methylene lactone monomer of the present invention is also provided. It is one of the inventions.
Further, the methylene lactone polymer produced by such a method for producing a methylene lactone polymer of the present invention is also one aspect of the present invention.
The method for producing a methylene lactone polymer of the present invention is a form in which the methylene lactone monomer is subjected to a polymerization reaction after the method for preserving the methylene lactone monomer of the present invention, and the dissolved oxygen amount is less than the amount of dissolved oxygen in the present invention. A mode in which the methylene lactone monomer is stored in the amount of oxygen and then mixed with the solution having the dissolved oxygen amount before being subjected to the polymerization reaction before the methylene lactone monomer is subjected to the polymerization reaction, and then the polymerization reaction is carried out as the methylene lactone monomer of the present invention. In addition, after the methylene lactone monomer is stored at a large amount of the polymerization inhibitor concentration deviating from the polymerization inhibitor concentration in the present invention, the methylene lactone monomer is subjected to distillation or the like before being subjected to the polymerization reaction. The methylene lactone monomer of the present invention or the storage method of the methylene lactone monomer of the present invention As long as it is used methylene lactone monomer after the manufacturing process is not particularly limited. However, from the viewpoint of ease of production of the methylene lactone polymer, the method for producing the methylene lactone polymer of the present invention is obtained by polymerizing the methylene lactone monomer after performing the method for storing the methylene lactone monomer of the present invention. It is preferable that the form is used for the reaction.
In the above method for producing a methylene lactone polymer, the lower the amount of dissolved oxygen in the methylene lactone monomer, the lower the polymerizability is different from the normal monomer as described above. Even in such a case, for example, it is possible to obtain a polymer as designed by setting reaction conditions such as increasing the polymerization reaction time when the methylene lactone monomer is subjected to the polymerization reaction. It is. Therefore, in the present invention, it is preferable to appropriately adjust the reaction conditions in the dissolved oxygen amount range in consideration of the peculiarity of the methylene lactone monomer.
The case where a methylene lactone polymer used for an optical material application is produced is described below.

In the production of the polymer using the methylene lactone monomer as a raw material, the temperature of the polymerization reaction is preferably -100 to 200 ° C. More preferably, it is 0-100 degreeC.

The monomer component as a raw material of the polymer may contain other monomers as long as it contains a methylene lactone monomer, but the methylene lactone monomer is contained in 100% by mass of the total monomer components. 5 to 100% by mass is preferable. More preferably, it is 10-100 mass%. When the methylene lactone compound is less than 5% by mass, the heat resistance, solvent resistance, and surface hardness may be insufficient.

Other monomers included in the monomer component include (meth) acrylic acid ester, α-hydroxymethyl acrylic acid ester, unsaturated carboxylic acid, styrene, vinyl toluene, divinylbenzene, α-methyl styrene, acrylonitrile, Examples thereof include methyl vinyl ketone, ethylene, propylene, butene, isobutene, butadiene, isoprene, vinyl acetate and the like, and these can be used alone or in combination. Although it does not specifically limit as (meth) acrylic acid ester, For example, methyl acrylate, ethyl acrylate, acrylate n-butyl, acrylate isobutyl, acrylate acrylate, cyclohexyl acrylate, benzyl acrylate, acrylic Acrylic acid esters such as 2-ethylhexyl acid; methyl methacrylate, ethyl methacrylate, propyl methacrylate, n-butyl methacrylate, isobutyl methacrylate, t-butyl methacrylate, cyclohexyl methacrylate, benzyl methacrylate, methacrylic acid And methacrylic acid esters such as 2-ethylhexyl acid. Examples of the α-hydroxymethyl acrylate include methyl α-hydroxymethyl acrylate, ethyl α-hydroxymethyl acrylate, butyl α-hydroxymethyl acrylate, cyclohexyl α-hydroxymethyl acrylate, and the like. Examples of the unsaturated carboxylic acid include acrylic acid, methacrylic acid, crotonic acid, α-substituted acrylic acid and the like. Among these, methyl acrylate, ethyl acrylate, n-butyl acrylate, isobutyl acrylate, t-butyl acrylate, cyclohexyl acrylate, benzyl acrylate, 2-ethylhexyl acrylate, methyl methacrylate, Ethyl methacrylate, propyl methacrylate, n-butyl methacrylate, isobutyl methacrylate, t-butyl methacrylate, cyclohexyl methacrylate, benzyl methacrylate, 2-ethylhexyl methacrylate, methyl α-hydroxymethyl acrylate, α-hydroxymethyl ethyl acrylate, α-hydroxymethyl butyl acrylate, acrylic acid, methacrylic acid, crotonic acid, α-substituted acrylic acid, styrene, divinylbenzene, α-methylstyrene, acrylonitrile, ethylene, propylene, Butene, isobutene, butadiene, isoprene and vinyl acetate are preferred. More preferably, methyl acrylate, ethyl acrylate, n-butyl acrylate, t-butyl acrylate, cyclohexyl acrylate, 2-ethylhexyl acrylate, methyl methacrylate, ethyl methacrylate, propyl methacrylate, N-butyl methacrylate, t-butyl methacrylate, cyclohexyl methacrylate, 2-ethylhexyl methacrylate, methyl α-hydroxymethyl allylate, ethyl α-hydroxymethyl acrylate, acrylic acid, methacrylic acid, croton Acid, α-substituted acrylic acid, styrene, divinylbenzene, α-methylstyrene, acrylonitrile, ethylene, propylene, butadiene, isoprene, and vinyl acetate.

The production of the polymer may be performed without using a solvent, or may be performed using a solvent. When a solvent is used, the solvent is not particularly limited. For example, aromatic hydrocarbon solvents such as toluene, xylene, and ethylbenzene; ketone solvents such as methyl ethyl ketone and methyl isobutyl ketone; ethers such as tetrahydrofuran Solvent; dimethyl sulfoxide, N, N-dimethylformamide, N, N-dimethylacetamide, N-methylpyrrolidone, chloroform, γ-butyrolactone, and the like can be used, and one or more of these can be used. Among these, toluene, xylene, ethylbenzene, methyl ethyl ketone, methyl isobutyl ketone, tetrahydrofuran, dimethyl sulfoxide, N, N-dimethylformamide, N, N-dimethylacetamide, N-methylpyrrolidone, and γ-butyrolactone are preferable. More preferred are toluene, xylene, ethylbenzene, methyl ethyl ketone, methyl isobutyl ketone, dimethyl sulfoxide, N, N-dimethylformamide, N, N-dimethylacetamide, and γ-butyrolactone. Moreover, since the residual volatile matter of the polymer finally obtained will increase when the boiling point of the solvent to be used is too high, a thing with a boiling point of 50-200 degreeC is preferable.

The amount of the solvent used is such that the monomer component, the solvent, and the total raw material solution including the polymerization initiator and chain transfer agent described later are 100% by mass, and the total monomer component concentration is 20 to 80. It is preferable to set so that it may become mass%, Preferably it is 30-70 mass%, More preferably, it is 40-60 mass%. When the monomer component concentration is lower than 20% by mass, the productivity is low. Furthermore, when a large amount of heat is required when the solvent is removed as a molding material, there is residual volatile content in the obtained molding material. May increase. On the other hand, when the monomer component concentration is higher than 80% by mass, the viscosity of the polymer solution increases with the progress of the polymerization, and it may be difficult to stir, extract, transfer and transport.

In the production of the polymer, a polymerization initiator can be used as necessary. The polymerization initiator is not particularly limited. For example, cumene hydroperoxide, diisopropylbenzene hydroperoxide, di-t-butyl peroxide, lauroyl peroxide, benzoyl peroxide, t-butylperoxyisopropyl Carbonate, t-amylperoxyisononanoate, t-amylperoxy-2-ethylhexanoate, 2,5-dimethyl-2,5-di (t-butylperoxy) hexane, 1,1′-di -T-butylperoxy-3,3,5-trimethylenecyclohexane, 1,3-di- (t-butylperoxy) -diisopropylbenzene, t-butyl hydroperoxide, t-butylperoxy-2-ethyl Hexanoate, t-butyl peroxypivalate, t-a Organic peroxides such as hydroperoxide; 2,2′-azobis (2-methylisobutyronitrile), 2,2′-azobis (isobutyronitrile), 1,1′-azobis (cyclohexanecarbonitrile) ), 2,2′-azobis (2,4-dimethylvaleronitrile), 2,2′-azobis (4-methoxy-2,4-dimethylvaleronitrile), 2,2′-azobis (isobutyric acid) dimethyl, An azo compound such as 4,4′-azobis (4-cyanovaleric acid) is preferred, and one or more of these can be used. Either one or both of organic peroxides and azo compounds may be used. The concentration of the polymerization initiator in the polymerization reaction may be appropriately adjusted according to the amount of the monomer component used, and is not particularly limited. For example, it is preferably 0 with respect to 100 parts by mass of the monomer. 0.001 to 3 parts by mass, more preferably 0.005 to 2 parts by mass. Moreover, you may superpose | polymerize using an ultraviolet-ray.

In the production of the polymer, a chain transfer agent can be used as necessary. The chain transfer agent is not particularly limited, but is preferably a mercaptan chain transfer agent such as n-dodecyl mercaptan, mercaptoacetic acid, methyl mercaptoacetate, α-methylstyrene dimer, and the like, one or two of these. The above can be used. More preferred are n-dodecyl mercaptan and mercaptoacetic acid, which have a high chain transfer effect, can reduce residual monomers, and are easily available. The amount of chain transfer agent used may be appropriately set according to the combination of monomers used, reaction conditions, target polymer molecular weight, and the like, and is not particularly limited. 5 mass% or less is preferable. More preferably, it is 1 mass% or less.

The polymer may have a ring structure other than a methylene lactone ring in the main chain. By giving the main chain a ring structure, the heat resistance of the polymer can be greatly improved. Examples of the ring structure include a ring structure including an ester group, an imide group, or an acid anhydride group in the ring structure. More specific examples of the ring structure include a lactone ring structure, a glutarimide structure, or a glutaric anhydride structure. The specific lactone structure that the polymer may have is not particularly limited. For example, the following formula (2);

(Wherein R ⁵ , R ⁶ and R ⁷ are each independently a hydrogen atom or an organic group having 1 to 20 carbon atoms. The organic group may contain an oxygen atom). It may be a structure.
The organic group is, for example, an alkyl group having 1 to 20 carbon atoms, such as a methyl group, an ethyl group, or a propyl group, an unsaturated hydrocarbon group having 1 to 20 carbon atoms, such as an ethenyl group or a propenyl group, or a phenyl group. , An aromatic hydrocarbon group having 1 to 20 carbon atoms such as a naphthyl group, and one or more of hydrogen atoms in these alkyl group, unsaturated hydrocarbon group, and aromatic hydrocarbon group are a hydroxyl group, a carboxyl group, And a group substituted with at least one group selected from an ether group and an ester group.

The lactone ring structure represented by the above formula (2) is adjacent to each other in the obtained copolymer after copolymerizing a monomer group including, for example, methyl methacrylate and methyl 2- (hydroxymethyl) acrylate. It can be formed by subjecting a methyl methacrylate unit and a methyl 2- (hydroxymethyl) acrylate to dealcoholization cyclocondensation. At this time, R ⁵ is H, R ⁶ is CH ₃ , and R ⁷ is CH ₃ .

The glutarimide structure that the polymer may have has the following formula (3):

(Wherein R ⁸ , R ⁹ and R ¹⁰ are each independently a hydrogen atom or a group exemplified as the organic group in the above formula (2)).
The glutarimide structure can be formed, for example, by polymerizing a monomer group containing (meth) acrylic acid ester and imidizing the obtained polymer with an imidizing agent such as methylamine.
The glutaric anhydride structure that the polymer may have has the following formula (4):

(Wherein R ¹¹ and R ¹² are each independently a hydrogen atom or a group exemplified as the organic group in the above formula (2)).
The glutaric anhydride structure is obtained by, for example, copolymerizing a monomer group containing (meth) acrylic acid ester and (meth) acrylic acid, and then subjecting the obtained copolymer to dealcoholization cyclocondensation in the molecule. Can be formed.

As the weight average molecular weight of the polymer, the weight average molecular weight required varies depending on the purpose of use of the polymer. For example, in the range of 1000 to 2,000,000, the polymer can be used sufficiently. You can say that.
The weight average molecular weight can be measured, for example, by performing gel permeation chromatography analysis using HLC-8220 GPC manufactured by Tosoh Corporation and using TSK-Gel Super HZM-M as a column.

The methylene lactone monomer of the present invention has a dissolved oxygen amount of 0.02 mg / L or more, and a polymerization inhibitor amount that substantially acts on the methylene lactone monomer as a polymerization inhibitor amount relative to the mass of the methylene lactone monomer. The coexistence of the polymerization inhibitor concentration expressed as a ratio at a concentration of 0.1% by mass or less suppresses a decrease in polymerizability such as a decrease in polymerization rate or a long induction period until the start of polymerization. In addition, since the coloration of the methylene lactone monomer and the generation of odor are suppressed, the polymerization can be promoted, and as the monomer in which the coloration and odor are sufficiently suppressed, It can be suitably used as a raw material for producing an industrial polymer.
In addition, the methylene lactone monomer has a dissolved oxygen amount of 0.02 mg / L or more, and a polymerization inhibitor amount of the methylene lactone monomer in which the polymerization inhibitor substantially acts on the methylene lactone monomer. Since the polymerization inhibitor concentration expressed as a ratio to the mass is a coexisting solution with a concentration of 0.1% by mass or less, the polymerization of the methylene lactone monomer during storage is effectively suppressed. A polymerization inhibitor concentration of 0.1% by mass expressed as a ratio of a polymerization inhibitor amount at which the polymerization inhibitor substantially acts on the methylenelactone monomer to a mass of the methylenelactone monomer at 0.02 mg / L or more. Making the solution coexisting at the following concentrations is a preferable method for storing the methylene lactone monomer.

FIG. 1 is a diagram showing UV-VIS spectra of Sample D and Sample E in the example. FIG. 2 is a diagram showing UV-VIS spectra of samples Q, Q ′, R, and S in Examples.

The present invention will be described in more detail with reference to the following examples. However, the present invention is not limited to these examples.

As α-methylene-γ-valerolactone, a reagent purchased from Tokyo Kasei (light yellow) was purified by distillation under reduced pressure. α-methylene-γ-butyrolactone was synthesized with reference to US Pat. No. 5,166,357, except that it was purified (colorless) by column chromatography instead of vacuum distillation. γ-Hexyl-α-methylene-γ-butyrolactone was synthesized with reference to International Publication No. 2008/023823.
The amount of dissolved oxygen was measured using an oxygen meter (UC-12-SOL type / electrode used: UC-203 type) manufactured by Central Science Co., Ltd.
Ultraviolet-visible spectroscopic analysis (UV-VIS) was performed by using a UV-1650PC manufactured by SHIMADZU and placing the sample directly in a semi-micro black cell.
Gas chromatographic analysis was performed using Agilent 6890N and using GL Sciences capillary column InertCap as the column.
Gel permeation chromatography analysis was performed using HLC-8220 GPC manufactured by Tosoh Corporation and using TSK-Gel Super HZM-M as a column, and the weight average molecular weight was measured.
For NMR, a nuclear magnetic resonance apparatus FT-NMR (400 MHz) manufactured by Varian was used.
In the following examples, when the baseline of the spectrum does not necessarily coincide with zero due to operational reasons such as different experiment days, the absorbance is determined with the 700-800 nm portion of the spectrum as the base (zero). It was decided to read the numbers.

Samples A to D were prepared according to the following.
(Sample A)
α-methylene-γ-valerolactone (10 g) was placed in a sample bottle and nitrogen was bubbled. The amount of dissolved oxygen was 0.01 mg / L. The gas phase part in the sample bottle was replaced with nitrogen, and left at 20 ° C. for 2 months. After 2 months, the solution was confirmed to be colorless and transparent.
(Sample B)
α-methylene-γ-valerolactone (10 g) was taken into a sample bottle and bubbled with oxygen. The amount of dissolved oxygen was 0.1 mg / L. The gas phase portion in the sample bottle was replaced with air, and left at 20 ° C. for 2 months. After 2 months, the solution was confirmed to be colorless and transparent.
(Sample C)
α-methylene-γ-valerolactone (10 g) was put in a sample bottle and oxygen was sufficiently bubbled. The amount of dissolved oxygen was 12.8 mg / L. The gas phase portion in the sample bottle was replaced with oxygen, and left at 20 ° C. for 2 months. After 2 months, the solution was confirmed to be colorless and transparent.
(Sample D)
α-methylene-γ-valerolactone (10 g) was placed in a sample bottle and bubbled with air. The amount of dissolved oxygen was 2.4 mg / L. The gas phase portion in the sample bottle was replaced with air, and left at 20 ° C. for 2 months. After 2 months, the solution was confirmed to be colorless and transparent.

(Reference Example 1)
Sample A (0.8 g) was charged into the reactor. While introducing nitrogen gas into the reaction vessel, 2,2′-azobis (2-methylisobutyronitrile) (0.002 g) was added as a polymerization initiator to obtain a uniform solution. It took 35 minutes to raise the temperature of the reaction solution to 85 ° C. while still standing and visually confirm the time until curing.
In addition, the time until hardening refers to the time until the polymerization of α-methylene-γ-valerolactone proceeds and the fluidity is lost.

(Reference Example 2)
Sample B (0.8 g) was charged into the reactor. While introducing nitrogen gas into the reaction vessel, 2,2′-azobis (2-methylisobutyronitrile) (0.002 g) was added as a polymerization initiator to obtain a uniform solution. It was 25 minutes when the temperature of the reaction liquid was raised to 85 ° C. while still standing and visually confirmed. The obtained polymer was colorless.

(Reference Example 3)
Sample C (0.8 g) was charged into the reactor. While introducing nitrogen gas into the reaction vessel, 2,2′-azobis (2-methylisobutyronitrile) (0.002 g) was added as a polymerization initiator to obtain a uniform solution. It was 23 minutes when the temperature of the reaction liquid was raised to 85 ° C. while still standing, and the time until curing was visually confirmed. The obtained polymer was colorless.

(Reference Example 4)
Sample D (0.8 g) was charged into the reactor. While introducing nitrogen gas into the reaction vessel, 2,2′-azobis (2-methylisobutyronitrile) (0.002 g) was added as a polymerization initiator to obtain a uniform solution. It was 23 minutes when the temperature of the reaction liquid was raised to 85 ° C. while still standing, and the time until curing was visually confirmed. The obtained polymer was colorless.

(Reference Example 5 (Sample E))
α-methylene-γ-valerolactone (10 g) was put in a sample bottle, 0.15% by mass of hydroquinone was added thereto, and air was bubbled. The amount of dissolved oxygen was 2.2 mg / L. The gas phase portion in the sample bottle was replaced with air, and left at 20 ° C. for 2 months. The solution became light yellow after 2 months.

(Reference Example 6 (Sample F))
α-methylene-γ-butyrolactone (10 g) was placed in a sample bottle and bubbled with air. The amount of dissolved oxygen was 2.0 mg / L. The gas phase part of the sample bottle was replaced with air, and left in the refrigerator (−10 ° C.) for 3 weeks. During this time, it was visually confirmed that α-methylene-γ-butyrolactone was not colored or cured.

(Reference Example 7 (Sample G))
α-methylene-γ-butyrolactone (10 g) was placed in a sample bottle and bubbled with air. The amount of dissolved oxygen was 2.4 mg / L. The gas phase part of the sample bottle was replaced with air and allowed to stand at room temperature (25 ° C.) for 3 weeks. During this time, it was visually confirmed that α-methylene-γ-butyrolactone was not colored or cured.

(Reference Example 8 (Sample H))
α-methylene-γ-butyrolactone (10 g) was placed in a sample bottle and bubbled with air. The amount of dissolved oxygen was 2.3 mg / L. The gas phase part of the sample bottle was replaced with air, and left at 50 ° C. for 3 weeks. During this time, it was visually confirmed that α-methylene-γ-butyrolactone was not colored or cured.

(Reference Example 9 (Sample I))
α-methylene-γ-butyrolactone (10 g) was placed in a sample bottle and bubbled with air. The amount of dissolved oxygen was 2.3 mg / L. When the gas phase portion of the sample bottle was replaced with air and allowed to stand at 80 ° C., it was colored pale pink, and it was visually confirmed that α-methylene-γ-butyrolactone was not cured after 3 hours.
Samples A to I and Reference Examples 1 to 9 are summarized in Table 1. In Table 1, HQ of the polymerization inhibitor represents hydroquinone.

(Reference Example 10)
When UV-VIS of sample D and sample E was measured, the spectrum shown in FIG. 1 was obtained. Compared to sample D, sample E had a greater absorbance at 350 to 600 nm, and sample D was colorless, but sample E was observed to be colored pale yellow.

Sample J and Sample K were prepared according to the following.
(Sample J)
p-Methoxyphenol (0.01% by mass) was added to α-methylene-γ-valerolactone (20 g), bubbled with air, and stored at 20 ° C. for 2 months under air. The dissolved oxygen concentration was 2.4 mg / L, and it was confirmed that it was colorless and transparent after 2 months.
(Sample K)
p-Methoxyphenol (0.005 mass%) was added to α-methylene-γ-valerolactone (20 g), air was bubbled, and the mixture was stored under air at 20 ° C. for 2 months. The dissolved oxygen concentration was 2.6 mg / L, and it was confirmed that it was colorless and transparent after 2 months.

Example 1
Sample J (0.8 g) was added to a test tube, and 2,2′-azobis (2-methylisobutyronitrile) (0.002 g) was added as a polymerization initiator while introducing nitrogen gas. A uniform solution was obtained. When the temperature of the reaction solution was raised to 85 ° C. and allowed to stand for 60 minutes, the solution thickened and 17% of the charged amount of α-methylene-γ-valerolactone was polymerized to produce a polymer compound. This was confirmed by gas chromatography analysis and gel permeation chromatography analysis.

(Example 2)
Sample K (0.8 g) was added to a test tube, and while introducing nitrogen gas, 2,2′-azobis (2-methylisobutyronitrile) (0.002 g) was added as a polymerization initiator, A uniform solution was obtained. When the temperature of the reaction solution was raised to 85 ° C. and allowed to stand for 60 minutes, the solution thickened and 30% of the charged amount of α-methylene-γ-valerolactone was polymerized to produce a polymer compound. This was confirmed by gas chromatography analysis and gel permeation chromatography analysis.

(Example 3 (Sample L))
p-Methoxyphenol (0.001% by mass) was added to α-methylene-γ-valerolactone (20 g), bubbled with nitrogen, and stored at 20 ° C. under nitrogen for 2 months. The dissolved oxygen concentration was 0.02 mg / L, and it was confirmed that it was colorless and transparent after 2 months.

(Example 4 (Sample M))
p-Methoxyphenol (0.001% by mass) was added to α-methylene-γ-valerolactone (20 g), bubbled with oxygen, and stored at 20 ° C. under oxygen for 2 months. The dissolved oxygen concentration was 13 mg / L, and it was confirmed that it was colorless and transparent after 2 months.

(Example 5 (Sample N))
p-Methoxyphenol (0.001% by mass) was added to α-methylene-γ-valerolactone (20 g), air was bubbled, and the mixture was stored at 20 ° C. under air for 2 months. The dissolved oxygen concentration was 2.2 mg / L, and it was confirmed that it was colorless and transparent after 2 months.

Sample O and Sample P were prepared according to the following.
(Sample O)
2,6-di-tert-butyl-4-methylphenol (0.01% by mass) was added to α-methylene-γ-valerolactone (20 g), and air was bubbled and stored at 20 ° C. for 2 months under air. did. The dissolved oxygen concentration was 2.8 mg / L, and it was confirmed that it was colorless and transparent after 2 months.
(Sample P)
2,6-di-tert-butyl-4-methylphenol (0.005% by mass) was added to α-methylene-γ-valerolactone (20 g), bubbled with air and stored at 20 ° C. for 2 months under air. did. The dissolved oxygen concentration was 2.7 mg / L, and it was confirmed that it was colorless and transparent after 2 months.

(Example 6)
Sample O (0.8 g) was added to a test tube, and while introducing nitrogen gas, 2,2′-azobis (2-methylisobutyronitrile) (0.002 g) was added as a polymerization initiator, A uniform solution was obtained. When the temperature of the reaction solution was raised to 85 ° C. and allowed to stand for 60 minutes, the solution was cured and 26% of the charged amount of α-methylene-γ-valerolactone was polymerized to produce a polymer compound. Confirmed by chromatographic analysis and gel permeation chromatography analysis.

(Example 7)
Sample P (0.8 g) was added to a test tube, and while introducing nitrogen gas, 2,2′-azobis (2-methylisobutyronitrile) (0.002 g) was added as a polymerization initiator, A uniform solution was obtained. When the temperature of the reaction solution was raised to 85 ° C. and allowed to stand for 60 minutes, the solution thickened, and 55% of the charged amount of α-methylene-γ-valerolactone was cured to produce a polymer compound. This was confirmed by gas chromatography analysis and gel permeation chromatography analysis.

(Example 8 (Sample Q))
p-Methoxyphenol (0.1% by mass) was added to α-methylene-γ-valerolactone (20 g), air was bubbled, and the mixture was stored under air at 20 ° C. for 2 months. The dissolved oxygen concentration was 2.8 mg / L, and it was visually confirmed that it was colorless and transparent after 2 months. When UV-VIS was observed, spectrum Q (FIG. 2) was observed. When UV-VIS of α-methylene-γ-valerolactone was measured immediately after purification by distillation (without addition of a polymerization inhibitor), it was observed as spectrum Q ′ (FIG. 2).

(Example 9 (Sample R))
Pentaerythritol tetrakis (3-laurylthiopropionate) (0.1% by mass) was added to α-methylene-γ-valerolactone (20 g), bubbled with air, and stored under air at 20 ° C. for 2 months. The dissolved oxygen concentration was 2.4 mg / L, and it was visually confirmed that it was colorless and transparent after 2 months. When UV-VIS was observed, spectrum R (FIG. 2) was observed.

(Example 10 (Sample S))
Triphenyl phosphite (0.1% by mass) was added to α-methylene-γ-valerolactone (20 g), air was bubbled, and the mixture was stored under air at 20 ° C. for 2 months. The dissolved oxygen concentration was 2.2 mg / L, and it was visually confirmed that it was colorless and transparent after 2 months. When UV-VIS was observed, spectrum S (FIG. 2) was observed.

Sample T and sample U were prepared according to the following.
(Sample T)
It was determined by NMR that α-methylene-γ-valerolactone purchased from Tokyo Chemical Industry had a concentration of hydroquinone as a polymerization inhibitor of about 0.2 to 0.25% by mass. Distilled and purified α-methylene-γ-valerolactone (10 g) was placed in a sample bottle, hydroquinone (0.15% by mass) was added thereto, and air was bubbled. The amount of dissolved oxygen was 2.2 mg / L. The gas phase portion in the sample bottle was replaced with air, and left at 20 ° C. for 2 months. The solution became light yellow after 2 months.
(Sample U)
α-methylene-γ-valerolactone (10 g) was placed in a sample bottle, hydroquinone (0.15% by mass) was added thereto, and air was bubbled. The amount of dissolved oxygen was 0.01 mg / L. The gas phase portion in the sample bottle was replaced with air, and left at 20 ° C. for 2 months. After 2 months, the solution was colored pale yellow, and it was confirmed that the color was darker than Sample T.

(Comparative Example 1)
Sample T (0.8 g) was added to a test tube, and 2,2′-azobis (2-methylisobutyronitrile) (0.002 g) was added as a polymerization initiator while introducing nitrogen gas. A uniform solution was obtained. The reaction solution was heated to 85 ° C. and allowed to stand for 60 minutes, but polymerization did not proceed.

(Comparative Example 2)
Sample U (0.8 g) was added to a test tube, and 2,2′-azobis (2-methylisobutyronitrile) (0.002 g) was added as a polymerization initiator while introducing nitrogen gas. A uniform solution was obtained. The reaction solution was heated to 85 ° C. and allowed to stand for 60 minutes, but polymerization did not proceed.

(Example 11 (Sample V))
p-Methoxyphenol (0.1% by mass) was added to α-methylene-γ-butyrolactone (20 g), air was bubbled, and the mixture was stored at 50 ° C. for 3 weeks under air. The dissolved oxygen concentration was 2.3 mg / L, and it was confirmed that it was colorless and transparent after 3 weeks.

Sample W to Sample Y were prepared according to the following.
(Sample W)
α-methylene-γ-butyrolactone (10 g) was placed in a sample bottle, p-methoxyphenol (0.15% by mass) was added thereto, and air was bubbled. The amount of dissolved oxygen was 3.1 mg / L. The gas phase part of the sample bottle was replaced with air and allowed to stand at 20 ° C. for 1 month. After one month, the solution became very slightly pale yellow.
(Sample X)
α-methylene-γ-valerolactone (40 g) mixed with 2,6-di-tert-butyl-4-methylphenol and triphenyl phosphite (1/1 <mass% / mass%>) ( 0.01 mass%) was added, air was bubbled, and it was stored under air at 20 ° C. for 6 months. The dissolved oxygen concentration was 3.1 mg / L, and it was confirmed that it was colorless and transparent after 6 months.
(Sample Y)
α-methylene-γ-valerolactone (40 g) mixed with 2,6-di-tert-butyl-4-methylphenol and pentaerythritol tetrakis (3-laurylthiopropionate) (1/1 < Mass% / mass%>) (0.01 mass%) was added, air was bubbled, and the mixture was stored under air at 20 ° C. for 6 months. The dissolved oxygen concentration was 3.1 mg / L, and it was confirmed that it was colorless and transparent after 6 months.

(Comparative Example 3)
Sample W (0.8 g) was added to a test tube, and 2,2′-azobis (2-methylisobutyronitrile) (0.002 g) was added as a polymerization initiator while introducing nitrogen gas. A uniform solution was obtained. The reaction solution was heated to 85 ° C. and allowed to stand for 60 minutes, but polymerization did not proceed.

Example 12
Sample X (0.8 g) was added to a test tube, and 2,2′-azobis (2-methylisobutyronitrile) (0.002 g) was added as a polymerization initiator while introducing nitrogen gas thereto, A uniform solution was obtained. When the temperature of the reaction solution was raised to 85 ° C. and allowed to stand for 60 minutes, the solution thickened and 18% of the charged amount of α-methylene-γ-valerolactone was polymerized to produce a polymer compound. This was confirmed by gas chromatography analysis and gel permeation chromatography analysis.

(Example 13)
Sample Y (0.8 g) was added to a test tube, and while introducing nitrogen gas, 2,2′-azobis (2-methylisobutyronitrile) (0.002 g) was added as a polymerization initiator, A uniform solution was obtained. When the temperature of the reaction solution was raised to 85 ° C. and allowed to stand for 60 minutes, the solution thickened and 35% of the charged amount of α-methylene-γ-valerolactone was polymerized to produce a polymer compound. This was confirmed by gas chromatography analysis and gel permeation chromatography analysis.
Samples J to Y, Examples 1 to 13, and Comparative Examples 1 to 3 are summarized in Table 2.
Abbreviations in Table 2 are as follows.
GVL: α-methylene-γ-valerolactone GBL: α-methylene-γ-butyrolactone α: p-methoxyphenol β: 2,6-di-t-butyl-4-methylphenol γ: pentaerythritol tetrakis (3-lauryl Thiopropionate)
δ: triphenyl phosphite HQ: hydroquinone ε: mixed polymerization inhibitor of 2,6-di-t-butyl-4-methylphenol and triphenyl phosphite (1/1 <mass% / mass%>)
ζ: inhibitor of mixed polymerization of 2,6-di-t-butyl-4-methylphenol and pentaerythritol tetrakis (3-laurylthiopropionate) (1/1 <mass% / mass%>)

Sample Z to Sample AC were prepared according to the following.
(Sample Z)
Air was bubbled through γ-hexyl-α-methylene-γ-butyrolactone (20 g) and stored under air at 20 ° C. for 6 months. The dissolved oxygen concentration was 5.3 mg / L, and it was confirmed that it was colorless and transparent after 6 months.
(Sample AA)
γ-Hexyl-α-methylene-γ-butyrolactone (20 g) was stored at 20 ° C. under nitrogen for 6 months. The dissolved oxygen concentration was 0.02 mg / L, and it was confirmed that it was colorless and transparent after 6 months.
(Sample AB)
Topanol (0.001% by mass) was added to α-methylene-γ-valerolactone (40 g), air was bubbled, and the mixture was stored under air at 20 ° C. for 2 months. The dissolved oxygen concentration was 3.3 mg / L, and it was confirmed that it was colorless and transparent after 2 months.
(Sample AC)
Topanol (0.001% by mass) was added to α-methylene-γ-valerolactone (40 g) and stored at 20 ° C. for 2 months under nitrogen. The dissolved oxygen concentration was 0.02 mg / L, and it was confirmed that it was colorless and transparent after 2 months.

(Reference Example 11)
Sample Z (1 g) and methyl isobutyl ketone having a dissolved oxygen concentration of 10.5 mg / L were added to a test tube, and 2,2′-azobis (2-methylisobutyro) was used as a polymerization initiator while introducing nitrogen gas. Nitrile) (0.0025 g) was added to make a uniform solution. When the temperature of the reaction solution was raised to 85 ° C. and allowed to stand for 20 minutes, the solution thickened and 73% of the charged amount of γ-hexyl-α-methylene-γ-butyrolactone was polymerized to form a polymer compound. This was confirmed by gas chromatography analysis.

(Reference Example 12)
Sample AA (1 g) and methyl isobutyl ketone having a dissolved oxygen concentration of 10.5 mg / L were added to a test tube, and 2,2′-azobis (2-methylisobutyro) was used as a polymerization initiator while introducing nitrogen gas. Nitrile) (0.0025 g) was added to make a uniform solution. When the temperature of the reaction solution was raised to 85 ° C. and allowed to stand for 20 minutes, the solution thickened and 59% of the charged amount of γ-hexyl-α-methylene-γ-butyrolactone was polymerized to form a polymer compound. This was confirmed by gas chromatography analysis.

(Reference Example 13)
Sample Z (1 g) was added to a test tube, and 2,2′-azobis (2-methylisobutyronitrile) (0.0025 g) was added as a polymerization initiator while introducing nitrogen gas into the test tube. It was set as the solution. The reaction solution was heated to 85 ° C. and allowed to stand for 60 minutes. The solution was cured, and it was confirmed by gel permeation chromatography analysis that the obtained polymer compound had a weight average molecular weight of 520,000.

(Reference Example 14)
Sample AA (1 g) was added to a test tube, and 2,2′-azobis (2-methylisobutyronitrile) (0.0025 g) was added as a polymerization initiator while introducing nitrogen gas into the test tube. It was set as the solution. The reaction solution was heated to 85 ° C. and allowed to stand for 60 minutes. The solution was cured, and it was confirmed by gel permeation chromatography analysis that the obtained polymer compound had a weight average molecular weight of 480,000.

(Example 14)
Sample AB (1 g) was added to a test tube, and 2,2′-azobis (2-methylisobutyronitrile) (0.0025 g) was added as a polymerization initiator while introducing nitrogen gas into the test tube. It was set as the solution. The reaction solution was heated to 85 ° C. and allowed to stand for 30 minutes. The solution was cured, and it was confirmed by gel permeation chromatography analysis that the obtained polymer compound had a weight average molecular weight of 450,000.

(Example 15)
Sample AC (1 g) was added to a test tube, and 2,2′-azobis (2-methylisobutyronitrile) (0.0025 g) was added as a polymerization initiator while introducing nitrogen gas into the test tube. It was set as the solution. The reaction solution was heated to 85 ° C. and allowed to stand for 30 minutes. The solution was cured, and it was confirmed by gel permeation chromatography analysis that the obtained polymer compound had a weight average molecular weight of 300,000.

(Reference Example 15)
Α-methylene-γ-valerolactone (20 g) having a dissolved oxygen concentration of 3.5 mg / L and p-methoxyphenol (0.02% by mass) were added to a test tube, and polymerization was performed while introducing nitrogen gas therein. 2,2′-Azobis (2-methylisobutyronitrile) (0.002 g) was added as an initiator to obtain a uniform solution. The reaction solution was heated to 85 ° C. and allowed to stand for 60 minutes, but polymerization did not proceed.

(Reference Example 16)
Α-methylene-γ-valerolactone (20 g) having a dissolved oxygen concentration of 3.5 mg / L and p-methoxyphenol (0.05% by mass) are added to a test tube, and polymerization is performed while introducing nitrogen gas therein. 2,2′-Azobis (2-methylisobutyronitrile) (0.002 g) was added as an initiator to obtain a uniform solution. The reaction solution was heated to 85 ° C. and allowed to stand for 60 minutes, but polymerization did not proceed.

(Reference Example 17)
Α-methylene-γ-valerolactone (20 g) having a dissolved oxygen concentration of 3.5 mg / L and p-methoxyphenol (0.1% by mass) were added to a test tube, and polymerization was conducted while introducing nitrogen gas therein. 2,2′-Azobis (2-methylisobutyronitrile) (0.002 g) was added as an initiator to obtain a uniform solution. The reaction solution was heated to 85 ° C. and allowed to stand for 60 minutes, but polymerization did not proceed.

(Reference Example 18)
Α-methylene-γ-valerolactone (20 g) having a dissolved oxygen concentration of 3.5 mg / L and 2,6-di-t-butyl-4-methylphenol (0.02% by mass) were added to a test tube. Then, while introducing nitrogen gas, 2,2′-azobis (2-methylisobutyronitrile) (0.002 g) was added as a polymerization initiator to obtain a uniform solution. When the temperature of the reaction solution was raised to 85 ° C. and allowed to stand for 60 minutes, the solution thickened and 15% of the charged amount of α-methylene-γ-valerolactone was polymerized to produce a polymer compound. This was confirmed by gas chromatography analysis and gel permeation chromatography analysis.

(Reference Example 19)
Α-methylene-γ-valerolactone (20 g) having a dissolved oxygen concentration of 3.5 mg / L and 2,6-di-t-butyl-4-methylphenol (0.05% by mass) were added to a test tube. Then, while introducing nitrogen gas, 2,2′-azobis (2-methylisobutyronitrile) (0.002 g) was added as a polymerization initiator to obtain a uniform solution. When the temperature of the reaction solution was raised to 85 ° C. and allowed to stand for 60 minutes, the solution thickened and 10% of the charged amount of α-methylene-γ-valerolactone was polymerized to produce a polymer compound. This was confirmed by gas chromatography analysis and gel permeation chromatography analysis.

(Reference Example 20)
Α-methylene-γ-valerolactone (20 g) having a dissolved oxygen concentration of 3.5 mg / L and 2,6-di-t-butyl-4-methylphenol (0.1% by mass) were added to a test tube. Then, while introducing nitrogen gas, 2,2′-azobis (2-methylisobutyronitrile) (0.002 g) was added as a polymerization initiator to obtain a uniform solution. The reaction solution was heated to 85 ° C. and allowed to stand for 60 minutes, but the polymerization did not proceed substantially, and an amount of less than 1% of the charged amount of α-methylene-γ-valerolactone was polymerized to produce a polymer compound. It was confirmed by gas chromatography analysis and gel permeation chromatography analysis.

Sample AD was prepared according to the following.
(Sample AD)
P-Methoxyphenol (0.1% by mass) was added to acrylic acid (20 g), air was bubbled, and the mixture was stored under air at 20 ° C. for 6 months. The dissolved oxygen concentration was 8.1 mg / L, and it was confirmed that it was colorless and transparent after 6 months.

(Comparative Example 4)
Sample AD (0.8 g) was added to a test tube, and while introducing nitrogen gas, 2,2′-azobis (2-methylisobutyronitrile) (0.002 g) was added as a polymerization initiator, A uniform solution was obtained. When the reaction solution was heated to 85 ° C. and allowed to stand for 60 minutes, the solution was cured, and 100% of the charged amount of acrylic acid was polymerized to produce a polymer compound. Gas chromatography analysis and gel permeation Confirmed by chromatographic analysis.
Examples 1, 2, 6, 7, Reference Examples 15 to 20 and Comparative Example 4 are summarized in Table 3.
Abbreviations in Table 3 are as follows.
GVL: α-methylene-γ-valerolactone AA: acrylic acid α: p-methoxyphenol β: 2,6-di-t-butyl-4-methylphenol

Samples AE to AH were prepared according to the following.
(Sample AE)
p-Methoxyphenol (0.05% by mass) was added to α-methylene-γ-butyrolactone (10 g), air was bubbled, and the mixture was stored under air at 35 ° C. for 1 month. The dissolved oxygen concentration was 3.0 mg / L, and it was confirmed that it was colorless and transparent after one month. During this time, polymerization of α-methylene-γ-butyrolactone was not observed.
(Sample AF)
p-Methoxyphenol (0.2% by mass) was added to α-methylene-γ-butyrolactone (10 g), air was bubbled, and the mixture was stored under air at 35 ° C. for 1 month. The dissolved oxygen concentration was 2.8 mg / L, and it was confirmed that it was colorless and transparent even after one month. During this time, polymerization of α-methylene-γ-butyrolactone was not observed.
(Sample AG)
P-Methoxyphenol (0.03% by mass) was added to acrylic acid (10 g), air was bubbled, and the mixture was stored under air at 20 ° C. for 6 months. The dissolved oxygen concentration was 8.5 mg / L, and it was confirmed that it was colorless and transparent after 6 months. During this time, polymerization of acrylic acid was not observed.
(Sample AH)
P-Methoxyphenol (0.2 mass%) was added to acrylic acid (10 g), air was bubbled, and the mixture was stored under air at 20 ° C. for 6 months. The dissolved oxygen concentration was 8.3 mg / L, and it was confirmed that it was colorless and transparent after 6 months. During this time, polymerization of acrylic acid was not observed.

(Example 16)
Sample AE (1.0 g) was added to a test tube, and 2,2′-azobis (2-methylisobutyronitrile) (0.001 g) was added as a polymerization initiator while introducing nitrogen gas. Solution. When the temperature of the reaction solution was raised to 85 ° C. and allowed to stand for 25 minutes, it was visually confirmed that the solution was cured.

(Comparative Example 5)
Sample AF (1.0 g) was added to a test tube, and 2,2′-azobis (2-methylisobutyronitrile) (0.001 g) was added as a polymerization initiator while introducing nitrogen gas. Solution. When the temperature of the reaction liquid was raised to 85 ° C. and allowed to stand for 90 minutes, it was visually confirmed that the liquid still maintained fluidity and did not cure.

(Comparative Example 6)
Sample AG (1.0 g) was added to a test tube, and while introducing nitrogen gas, 2,2′-azobis (2-methylisobutyronitrile) (0.001 g) was added as a polymerization initiator, and uniform. Solution. When the temperature of the reaction solution was raised to 85 ° C. and allowed to stand for 10 minutes, it was visually confirmed that the solution was cured.

(Comparative Example 7)
Sample AH (1.0 g) was added to a test tube, and 2,2′-azobis (2-methylisobutyronitrile) (0.001 g) was added as a polymerization initiator while introducing nitrogen gas, Solution. When the temperature of the reaction solution was raised to 85 ° C. and allowed to stand for 10 minutes, it was visually confirmed that the solution was cured.
Example 16 and Comparative Examples 5 to 7 are summarized in Table 4.
Abbreviations in Table 4 are as follows.
GBL: α-methylene-γ-butyrolactone AA: acrylic acid α: p-methoxyphenol

From the results of Reference Examples 1 to 14, only when the dissolved oxygen amount of the methylene lactone monomer is 0.02 mg / L or more, coloring during storage may be suppressed depending on the type of the methylene lactone monomer. It has been found that there are cases where a decrease in polymerizability is suppressed and cases where it is not suppressed. On the other hand, from the results of Examples 1 to 15, the dissolved oxygen amount of the methylene lactone monomer was 0.02 mg / L or more, and the polymerization inhibitor was allowed to coexist at a concentration of 0.1% by mass or less. It was confirmed that coloring during storage and a decrease in polymerizability could be reliably suppressed regardless of the type of lactone monomer.
Such suppression of the decrease in polymerizability is an outstanding effect in view of industrial productivity and product quality, and is an unexpected effect from the prior art.
In addition, from the results of Examples 14 and 15, when storing the methylene lactone monomer, both when stored under air and when stored under nitrogen, the amount of methylene lactone after storage without reducing the polymerizability The polymerization reaction can be carried out using the product, but when using a methylene lactone monomer stored under nitrogen, compared to using a methylene lactone monomer stored under air. It was found that the weight average molecular weight of the resulting methylene lactone polymer was slightly reduced. This is considered to be due to some chain transfer effect when a methylene lactone monomer stored under nitrogen is subjected to a polymerization reaction.
From the results of Examples 1, 2, 6, 7, Reference Examples 15 to 20, and Comparative Example 4, the specific polymerization inhibitor used in the present invention is an amount that hinders the polymerization of the methylene lactone monomer depending on the type of the polymerization inhibitor. Although it is different, it was confirmed that it has a polymerization inhibitory effect on the methylene lactone monomer at a specific concentration. On the other hand, for acrylic acid having a CH ₂ ═CH—COO— moiety as in the case of the methylene lactone monomer, it was confirmed that the same polymerization inhibitor did not exhibit a polymerization inhibitory effect at the above-mentioned specific concentration. It was done. Further, from the results of Example 16 and Comparative Examples 5 to 7, when the monomer is a methylene lactone monomer, the polymerization is inhibited by using a polymerization inhibitor exceeding the concentration of the polymerization inhibitor in the present invention. Although it does not proceed, when the monomer is acrylic acid, it is confirmed that the polymerization proceeds without being inhibited even when a polymerization inhibitor exceeding the polymerization inhibitor concentration in the present invention is used. Was found to be a problem peculiar to methylene lactone monomers. As described above, as described above, it is considered that the driving force of polymerization of the methylene lactone monomer is elimination of distortion of the ring structure and is different from that of other polymerizable monomers such as acrylic acid.
Therefore, it can be said that the effect of such a polymerization inhibitor is peculiar to the methylene lactone monomer, and the effect obtained depends on the type and amount of the polymerization inhibitor coexisting with the methylene lactone monomer. From the experimental results, it is important to specify the amount of the polymerization inhibitor, and it can be said that a specific type is preferable for the present invention.

Claims (8)

The following general formula (1);

(Wherein R ¹ , R ² , R ³ and R ⁴ are the same or different and each represents a hydrogen atom or a monovalent organic group),
The methylene lactone monomer is a solution having a dissolved oxygen amount of 0.02 mg / L or more and coexisting with a polymerization inhibitor. A methylene lactone monomer having a polymerization inhibitor concentration expressed as a ratio to the mass of the monomer, of 0.1% by mass or less. The methylene lactone monomer according to claim 1, wherein the polymerization inhibitor is at least one compound selected from the group consisting of thioether-based, phosphite-based, and phenol-based compounds. A methylene lactone monomer for a methylene lactone polymer material, comprising the methylene lactone monomer according to claim 1. The following general formula (1);

(Wherein R ¹ , R ² , R ³ and R ⁴ are the same or different and each represents a hydrogen atom or a monovalent organic group). There,
The storage method involves storing a methylene lactone monomer as a solution having a dissolved oxygen amount of 0.02 mg / L or more and a polymerization inhibitor coexisting, and a polymerization inhibitor amount that substantially acts on the methylene lactone monomer. A method for storing a methylene lactone monomer, comprising storing the polymerization inhibitor concentration expressed as a ratio to the mass of the methylene lactone monomer at 0.1% by mass or less. The methylene lactone monomer according to claim 4, wherein the polymerization inhibitor is at least one compound selected from the group consisting of thioether, phosphite, and phenolic compounds. Preservation method. 6. The method for storing a methylene lactone monomer according to claim 4 or 5, wherein the methylene lactone monomer is stored at a temperature of -50 to 80 [deg.] C. A methylene lactone heavy product produced by using the methylene lactone monomer according to claim 1 or 2 or the methylene lactone monomer after performing the storage method according to any one of claims 4 to 6. Manufacturing method of coalescence. A methylene lactone polymer produced by the method for producing a methylene lactone polymer according to claim 7.

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