Methyl methacrylate-containing composition and methyl methacrylate polymer production method

Abstract

The purpose of the present invention is to provide a methyl methacrylate-containing composition with high quality stability during storage. This can be solved with a methyl methacrylate-containing composition containing methyl methacrylate, an a,~unsaturated carbonyl compound represented by the following Formula (1), and a polymerization inhibitor, in which the concentration of methyl methacrylate is from 99 to 99.99% by mass.

Description

Methyl methacrylate-containing composition and method for producing methyl methacrylate polymer

[0001] The present invention relates to a methyl methacrylate-containing composition and a method for producing a methyl methacrylate polymer.

[0002] Methyl methacrylate (hereinafter also referred to as "MMA") is known to be an extremely useful substance used as a raw material for various types of polymers in a variety of applications. For example, polymethyl methacrylate, a homopolymer of methyl methacrylate, is used in signage, lighting equipment, automotive parts, building materials, light guide panels for flat displays, light diffusion panels, and other applications, taking advantage of its excellent transparency and weather resistance. Furthermore, copolymers of methyl methacrylate with other monomers are used in paints, adhesives, resin modifiers, artificial marble, paper latex, and other applications. Various methods for industrially producing methyl methacrylate have been developed, including the acetone cyanohydrin (ACH) method, the new acetone cyanohydrin (new ACH) method, the C4 direct oxidation method, the direct methacrylate method, the ethylene method, and the new ethylene method (Non-Patent Document 1). In these production methods, purification such as distillation is performed to remove unreacted raw materials and by-products contained in the resulting methyl methacrylate, thereby obtaining methyl methacrylate of a quality suitable for the intended application.

[0003] Because methyl methacrylate has a tendency to polymerize easily, it is known that the quality of methyl methacrylate is maintained by adding a polymerization inhibitor during its production and storage (Non-Patent Document 2). For example, Patent Document 1 describes that, among various polymerization inhibitors, methyl ether of hydroquinone (MEHQ) is particularly preferred. Patent Document 2 describes that, among various polymerization inhibitors, N,N'-dialkyl-p-phenylenediamine and N-oxyl are preferred. Patent Document 3 describes distilling methyl methacrylate in the presence of a phenolic polymerization inhibitor. Patent Document 4 describes the use of a diphenylamine derivative as a polymerization inhibitor. Patent Document 5 describes the use of a benzenetriamine derivative as a polymerization inhibitor.

[0004] Japanese Patent Application Laid-Open No. 2004-155757 Special Publication No. 2005-502695 Special Publication No. 10-504553 Special Publication No. 2002-533309 Special Publication No. 2002-513034

[0005] Toru Kuroda, "Development of Catalysts for the Production of Methyl Methacrylate," Catalysts, Catalysis Society of Japan, 2003, Vol. 45, No. 5, pp. 366-371; Takayuki Otsu, "Functions of Polymerization Inhibitors," Synthetic Organic Chemistry, Society of Synthetic Organic Chemistry, 1975, Vol. 33, No. 8, pp. 634-640

[0006] However, even when the polymerization inhibitor is added, the quality of methyl methacrylate may deteriorate during storage. In view of the above, an object of the present invention is to provide a methyl methacrylate-containing composition having high quality stability during storage.

[0007] The present inventors conducted extensive research to achieve the above-mentioned object. As a result, they found that in methyl methacrylate whose quality deteriorated during storage, the methyl methacrylate concentration decreased and methyl methacrylate dimer and methyl pyruvate were formed. The presence of methyl methacrylate dimer in methyl methacrylate can change the structure of the methyl methacrylate polymer obtained by polymerization, potentially adversely affecting its physical properties. Furthermore, the presence of methyl pyruvate in methyl methacrylate can cause discoloration of the methyl methacrylate polymer obtained by polymerization. They then discovered that when a methyl methacrylate-containing composition contains an α,β-unsaturated carbonyl compound of a specific structural formula, the quality stability during storage is improved and the formation of methyl methacrylate dimer and methyl pyruvate is suppressed, leading to the completion of the present invention.

[0008] That is, the present invention relates to the following items [1] to

[33] : [1]: A methyl methacrylate-containing composition comprising methyl methacrylate, an α,β-unsaturated carbonyl compound (component A1) represented by the following formula (1), and a polymerization inhibitor (component B), wherein the concentration of methyl methacrylate is 99 to 99.99% by mass: (In the above formula (1), R １ , R ２ and R ３R each independently represents a hydrogen atom, an alkyl group, an alkenyl group, an aryl group, a hydroxy group, an alkoxy group, an amino group, a monovalent group containing a carbonyl group, an alkylthio group, or an arylthio group. ４ represents a monovalent group including an alkyl group, an alkenyl group, an aryl group, a hydroxy group, an alkoxy group, an amino group, or a carbonyl group, an alkylthio group, or an arylthio group. １ and R ２ , R ２ and R ３ , R ３ and R ４ may be linked to each other to form a ring. １ = H, and R ２ = H, and R ３ =CH ３ and R ４ =OCH ３(i.e., excluding cases where the α,β-unsaturated carbonyl compound represented by formula (1) is methyl methacrylate. H represents a hydrogen atom, C represents a carbon atom, and O represents an oxygen atom.) [2]: The methyl methacrylate-containing composition according to [1], in which, when the concentration of component A1 is MA1 (μmol / L) and the concentration of component B is MB (μmol / L), MB / MA1 is 0.1 or more. [3]: The methyl methacrylate-containing composition according to [1] or [2], in which, when the concentration of component A1 is MA1 (μmol / L), MA1 is 1 to 85,000 μmol / L. [4]: ​​The methyl methacrylate-containing composition according to [3], in which MA1 is 10 to 40,000 μmol / L. [5]: The methyl methacrylate-containing composition according to any one of [1] to [4], wherein, when the concentration of Component B is expressed as MB (μmol / L), MB is 1 to 7,000 μmol / L. [6]: The methyl methacrylate-containing composition according to [5], wherein MB is 10 to 5,000 μmol / L. [7]: The methyl methacrylate-containing composition according to any one of [1] to [6], wherein Component A1 has a molecular weight of 1,000 or less. [8]: The methyl methacrylate-containing composition according to any one of [1] to [7], wherein Component B is at least one polymerization inhibitor selected from the group consisting of phenol-based compounds, quinone-based compounds, nitrobenzene-based compounds, N-oxyl-based compounds, amine-based compounds, phosphorus-containing compounds, sulfur-containing compounds, iron-containing compounds, copper-containing compounds, and manganese-containing compounds. [9]: The methyl methacrylate-containing composition according to any one of [1] to [8], wherein Component B is at least one polymerization inhibitor selected from the group consisting of phenolic compounds, N-oxyl compounds, amine compounds, phosphorus-containing compounds, and sulfur-containing compounds.

[10] : The methyl methacrylate-containing composition according to any one of [1] to [9], wherein Component B is at least one polymerization inhibitor selected from the group consisting of hydroquinone, 4-methoxyphenol, 2,4-dimethyl-6-t-butylphenol, 2,6-di-t-butyl-4-methylphenol, 4-hydroxy-2,2,6,6-tetramethylpiperidine-N-oxyl, N,N-diphenylamine, N-nitrosodiphenylamine, triphenyl phosphite, and phenothiazine.

[11] : R in the above formula (1). １ , R ２ and R ３ are each independently a hydrogen atom, an alkyl group having 1 to 5 carbon atoms, an alkenyl group having 2 to 5 carbon atoms, an aryl group having 1 to 12 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, an amino group, a monovalent group containing a carbonyl group, or an alkylthio group having 1 to 5 carbon atoms; R ４

[12] : The methyl methacrylate-containing composition according to any one of [1] to

[10] , wherein R is an alkyl group having 1 to 5 carbon atoms, an alkenyl group having 2 to 5 carbon atoms, an aryl group having 1 to 12 carbon atoms, a hydroxy group, an alkoxy group having 1 to 6 carbon atoms, an amino group, a monovalent group containing a carbonyl group, or an alkylthio group having 1 to 5 carbon atoms. １ , R ２ and R ３ are each independently a hydrogen atom or an alkyl group having 1 to 5 carbon atoms, and R ４

[13] : In the formula (1), R is an alkyl group having 1 to 5 carbon atoms or an alkoxy group having 1 to 5 carbon atoms. １ , R ２ and R ３ are each independently a hydrogen atom, a methyl group, an ethyl group, an n-propyl group, or an isopropyl group, and R ４is a methyl group, a methoxy group, an ethoxy group, an n-propoxy group, an isopropoxy group, an n-butoxy group, an isobutoxy group, or an isopentoxy group.

[14] : The methyl methacrylate-containing composition according to any one of [1] to

[13] , wherein the concentration of methyl methacrylate is 99.8 to 99.99 mass%.

[15] : The methyl methacrylate-containing composition according to any one of [1] to

[14] , wherein the concentration of diacetyl contained is 55 μmol / L or less.

[16] : A methyl methacrylate-containing composition comprising methyl methacrylate and an α,β-unsaturated carboxylic acid ester (component A2) represented by the following formula (2), wherein the concentration of the methyl methacrylate is 99 to 99.99 mass%, and when the concentration of the component A2 is MA2 (μmol / L), the MA2 is 1 to 40,000 μmol / L. (In the above formula (2), R ５ , R ６ and R ７ R each independently represents a hydrogen atom, an alkyl group, an alkenyl group, an aryl group, a hydroxy group, an alkoxy group, an amino group, a monovalent group containing a carbonyl group, an alkylthio group, or an arylthio group. ８ represents an alkyl group, an alkenyl group, or an aryl group. ５ and R ６ , R ６ and R ７ , R ７ and R ８ may be linked to each other to form a ring. ５ = H, and R ６ = H, and R ７ =CH ３ and R ８ =CH ３(Excluding cases where the α,β-unsaturated carbonyl compound represented by formula (2) is methyl methacrylate. H represents a hydrogen atom, C represents a carbon atom, and O represents an oxygen atom.)

[17] : The methyl methacrylate-containing composition according to

[16] , wherein the MA2 is 10 to 5000 μmol / L.

[18] : The methyl methacrylate-containing composition according to

[16] or

[17] , wherein the MA2 is 10 to 500 μmol / L.

[19] : The methyl methacrylate-containing composition according to any one of

[16] to

[18] , wherein the molecular weight of the component A2 is 1000 or less.

[20] : In the above formula (2), R ５ , R ６ and R ７ are each independently a hydrogen atom, an alkyl group having 1 to 5 carbon atoms, an alkenyl group having 2 to 5 carbon atoms, an aryl group having 1 to 12 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, an amino group, a monovalent group containing a carbonyl group, or an alkylthio group having 1 to 5 carbon atoms; R ８

[21] : In the formula (2), R is an alkyl group having 1 to 5 carbon atoms, an alkenyl group having 2 to 5 carbon atoms, or an aryl group having 1 to 12 carbon atoms. ５ , R ６ and R ７ are each independently a hydrogen atom or an alkyl group having 1 to 5 carbon atoms, and R ８

[22] : In the formula (2), R is an alkyl group having 1 to 5 carbon atoms. ５ , R ６ and R ７ are each independently a hydrogen atom, a methyl group, an ethyl group, an n-propyl group, or an isopropyl group, and R ８

[23] : In the formula (2), R is a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, an isobutyl group, or an isopentyl group. ５ , R ６ and R ７ are each independently a hydrogen atom or a methyl group, and R ８is a methyl group.

[24] : The methyl methacrylate-containing composition according to any one of

[16] to

[23] , wherein the concentration of methyl methacrylate is 99.8 to 99.99% by mass.

[25] : The methyl methacrylate-containing composition according to any one of

[16] to

[24] , wherein the concentration of diacetyl contained is 55 μmol / L or less.

[26] A methyl methacrylate-containing composition comprising methyl methacrylate and at least one compound (component A3) selected from the group consisting of methyl acrylate, butyl acrylate, ethyl methacrylate, methyl crotonate, cis-methyl crotonate, isobutyl methacrylate, butyl methacrylate, propyl methacrylate, isopentyl methacrylate, methyl 2-methylene-3-butenoate, methyl 3,3-dimethylacrylate, methyl 2-ethylacrylate, methyl 2-pentenoate, methyl cinnamate, methyl 3-methoxyacrylate, dimethyl fumarate, methyl 1-cyclohexene-1-carboxylate, methacrylamide, acrylic acid, crotonic acid, cis-crotonic acid, 3,3-dimethylacrylic acid, 2-ethylacrylic acid, 2-methylene-3-butenoic acid, and trans-3-hexen-2-one, wherein the concentration of methyl methacrylate is 99 to 99.99% by mass, A methyl methacrylate-containing composition in which, when the concentration of the component A3 is MA3 (μmol / L), MA3 is 1 to 40,000 μmol / L.

[27] : The methyl methacrylate-containing composition according to

[26] , in which MA3 is 10 to 5,000 μmol / L.

[28] : The methyl methacrylate-containing composition according to

[26] or

[27] , in which MA3 is 10 to 500 μmol / L.

[29] : The methyl methacrylate-containing composition according to any one of

[26] to

[28] , in which the component A3 is at least one selected from the group consisting of methyl acrylate, methyl crotonate, acrylic acid, and crotonic acid.

[30] : The methyl methacrylate-containing composition according to any one of

[26] to

[29] , in which the concentration of methyl methacrylate is 99.8 to 99.99 mass%.

[31] : The methyl methacrylate-containing composition according to any one of

[26] to

[30] , which does not contain diacetyl or contains diacetyl at a concentration of 55 μmol / L or less.

[32] : A method for producing a methyl methacrylate polymer, comprising a step of polymerizing a polymerizable composition containing the methyl methacrylate-containing composition according to any one of [1] to

[31] .

[33] : The method for producing a methyl methacrylate polymer according to

[32] , wherein the polymerizable composition contains 0.01% by mass or more of a monomer copolymerizable with methyl methacrylate per 100 parts by mass of methyl methacrylate.

[0009] According to the present invention, it is possible to provide a methyl methacrylate-containing composition having high quality stability in which the production of methyl methacrylate dimers and methyl pyruvate during storage is suppressed.

[0010] Hereinafter, embodiments of the present invention will be described, but the present invention is not limited to the following. In this specification, a numerical range expressed using "to" means a range that includes the numerical values ​​written before and after "to" as the lower and upper limits, and "A to B" means A or more and B or less.

[0011] [Methyl methacrylate-containing composition 1] A first aspect of the methyl methacrylate-containing composition according to the present invention is a methyl methacrylate-containing composition comprising methyl methacrylate, an α,β-unsaturated carbonyl compound (component A1) represented by the following formula (1), and a polymerization inhibitor (component B), wherein the concentration of methyl methacrylate is 99 to 99.99 mass%:

[0012] In the above formula (1), R １ , R ２ and R ３ R each independently represents a hydrogen atom, an alkyl group, an alkenyl group, an aryl group, a hydroxy group, an alkoxy group, an amino group, a monovalent group containing a carbonyl group, an alkylthio group, or an arylthio group. ４ represents a monovalent group including an alkyl group, an alkenyl group, an aryl group, a hydroxy group, an alkoxy group, an amino group, or a carbonyl group, an alkylthio group, or an arylthio group. １ and R ２ , R２ and R ３ , R ３ and R ４ may be linked to each other to form a ring. １ = H, and R ２ = H, and R ３ =CH ３ and R ４ =OCH ３ This excludes cases where the α,β-unsaturated carbonyl compound represented by formula (1) is methyl methacrylate. H represents a hydrogen atom, C represents a carbon atom, and O represents an oxygen atom. The methyl methacrylate-containing composition may also contain other compounds (component C) and water, as long as the concentration of methyl methacrylate satisfies 99 to 99.99% by mass. Each item will be explained in detail below.

[0013] (Component A1) A first aspect of the methyl methacrylate-containing composition according to the present invention contains an α,β-unsaturated carbonyl compound (Component A1) represented by the formula (1). The coexistence of Component A1 and Component B, which will be described later, can suppress the production of methyl methacrylate dimers and methyl pyruvate during storage of the methyl methacrylate-containing composition. The reason for this is presumed to be as follows.

[0014] Methyl methacrylate dimers are produced by radicals generated during storage of methyl methacrylate. Examples of such radicals include hydroxyl radicals, which are generated when oxygen molecules absorb ultraviolet light derived from sunlight. Hydroxyl radicals can also cause the oxidation of methyl methacrylate to produce methyl pyruvate. α,β-Unsaturated carbonyl compounds absorb ultraviolet light due to their conjugated double bonds, and the absorption wavelength varies depending on the type of substituent. α,β-Unsaturated carbonyl compounds having the structure represented by formula (1) can absorb ultraviolet light over a wide range of wavelengths. Therefore, when a methyl methacrylate-containing composition contains component A1, ultraviolet light over a wide range of wavelengths is absorbed, suppressing the generation of hydroxyl radicals. Furthermore, by including component B, described below, generated hydroxyl radicals can be trapped. Therefore, it is believed that the coexistence of component A1 and component B can efficiently suppress the generation of methyl methacrylate dimers and methyl pyruvate. Among various organic compounds that absorb ultraviolet light, α,β-unsaturated carbonyl compounds have a molecular structure similar to that of methyl methacrylate, and therefore, when a polymer is produced using the methyl methacrylate-containing composition as a raw material, the adverse effects of the α,β-unsaturated carbonyl compounds being contained as impurities can be reduced.

[0015] The molecular weight of component A1 is preferably 1000 or less. By having a molecular weight of 1000 or less, the number of conjugated double bonds per unit mass in component A1 can be increased, and the effects of the present invention can be obtained with a small mass. The molecular weight of component A1 is more preferably 800 or less, even more preferably 600 or less, and particularly preferably 400 or less.

[0016] R in the formula (1) １ , R ２ and R ３ each independently represents a hydrogen atom, an alkyl group, an alkenyl group, an aryl group, a hydroxy group, an alkoxy group, an amino group, a monovalent group containing a carbonyl group, an alkylthio group, or an arylthio group. ４represents a monovalent group including an alkyl group, an alkenyl group, an aryl group, a hydroxy group, an alkoxy group, an amino group, or a carbonyl group, an alkylthio group, or an arylthio group. １ , R ２ , R ３ and R ４ may be the same or different.

[0017] R １ 、 R ２ 、 R ３ and R ４ When R satisfies the above condition, the π-conjugated system of component A1 is maintained, and therefore the compound has the property of absorbing ultraviolet light over a wide wavelength range, thereby achieving the effects of the present invention. １ , R ２ and R ３ is preferably a hydrogen atom, an alkyl group having 1 to 5 carbon atoms, an alkenyl group having 2 to 5 carbon atoms, an aryl group having 1 to 12 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, an amino group, a monovalent group containing a carbonyl group, or an alkylthio group having 1 to 5 carbon atoms. These are highly stable substituents, and can prevent Component A1 from changing into other compounds during storage. Furthermore, when Component A1 has these substituents, the amount of ultraviolet light that can be absorbed by one molecule of Component A1 is sufficient. １ , R ２ and R ３ is more preferably a hydrogen atom or an alkyl group having 1 to 5 carbon atoms, and even more preferably a hydrogen atom, a methyl group, an ethyl group, an n-propyl group, or an isopropyl group. ４ is preferably an alkyl group having 1 to 5 carbon atoms, an alkenyl group having 2 to 5 carbon atoms, an aryl group having 1 to 12 carbon atoms, a hydroxy group, an alkoxy group having 1 to 6 carbon atoms, an amino group, a monovalent group containing a carbonyl group, or an alkylthio group having 1 to 5 carbon atoms. These are highly stable substituents, and can prevent component A1 from changing into other compounds during storage. ４is more preferably an alkyl group having 1 to 5 carbon atoms or an alkoxy group having 1 to 5 carbon atoms, and even more preferably a methyl group, a methoxy group, an ethoxy group, an n-propoxy group, an isopropoxy group, an n-butoxy group, an isobutoxy group, or an isopentoxy group. ４ When the structure is as described above, the quality stability of the methyl methacrylate-containing composition during storage can be improved.

[0018] The alkyl group is a chain (straight-chain or branched) alkyl group or a cyclic alkyl group. An alkyl group having 1 to 20 carbon atoms is preferred, an alkyl group having 1 to 10 carbon atoms is more preferred, and an alkyl group having 1 to 5 carbon atoms is even more preferred. Examples of the chain alkyl group include a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, an isobutyl group, an s-butyl group, a t-butyl group, an n-pentyl group, an isopentyl group, a hexyl group, an octyl group, a decyl group, a hydroxymethyl group, a 1-hydroxyethyl group, and a 2-hydroxyethyl group, with a methyl group, an ethyl group, an n-propyl group, and an isopropyl group being preferred. Examples of the cyclic alkyl group include a cyclopentyl group, a cyclohexyl group, and a cyclooctyl group.

[0019] The alkenyl group is a chain (straight-chain or branched) alkenyl group or a cyclic alkenyl group. An alkenyl group having 2 to 20 carbon atoms is preferred, an alkenyl group having 2 to 10 carbon atoms is more preferred, and an alkenyl group having 2 to 5 carbon atoms is even more preferred. Examples of chain alkenyl groups include vinyl, 1-propenyl, isopropenyl, 2-butenyl, 1,3-butadienyl, 2-pentenyl, and 2-hexenyl groups. Examples of cyclic alkenyl groups include cyclopentenyl and cyclohexenyl groups.

[0020] The aryl group is preferably an aryl group having 1 to 20 carbon atoms, more preferably an aryl group having 1 to 12 carbon atoms. The aryl group includes heteroaryl groups containing oxygen, nitrogen, sulfur, or the like. Examples of the aryl group include a phenyl group, a mesityl group, a naphthyl group, a 2-methylphenyl group, a 3-methylphenyl group, a 4-methylphenyl group, a 2,3-dimethylphenyl group, a 2,4-dimethylphenyl group, a 2,5-dimethylphenyl group, a 2,6-dimethylphenyl group, a 2-ethylphenyl group, an isoxazolyl group, an isothiazolyl group, an imidazolyl group, an oxazolyl group, a thiazolyl group, a thiadiazolyl group, a thienyl group, a triazolyl group, a tetrazolyl group, a pyridyl group, a pyrazinyl group, a pyrimidinyl group, a pyridazinyl group, a pyrazolyl group, a pyrrolyl group, a furyl group, a furazanyl group, an isoquinolyl group, an isoindolyl group, an indolyl group, a quinolyl group, a pyridothiazolyl group, a benzimidazolyl group, a benzoxazolyl group, a benzothiazolyl group, a benzotriazolyl group, a benzofuranyl group, an imidazopyridinyl group, a triazopyridinyl group, and a purinyl group.

[0021] The alkoxy group is preferably an alkoxy group having 1 to 20 carbon atoms, more preferably an alkoxy group having 1 to 10 carbon atoms, and even more preferably an alkoxy group having 1 to 6 carbon atoms. Examples of the alkoxy group include a methoxy group, an ethoxy group, an n-propoxy group, an isopropoxy group, an n-butoxy group, an isobutoxy group, an s-butoxy group, a t-butoxy group, an n-pentoxy group, an isopentoxy group, and a phenoxy group.

[0022] The amino group is an amino group with no substituent on the nitrogen atom (-NH ２ ) and an amino group in which some or all of the hydrogen atoms bonded to the nitrogen atom have been substituted with carbon atoms. The number of carbon atoms in the amino group substituted with carbon atoms is preferably 1 to 20, more preferably 1 to 10, and even more preferably 1 to 5. Examples of the amino group include a methylamino group, an ethylamino group, a propylamino group, a butylamino group, a dimethylamino group, a diethylamino group, an anilino group, a toluidino group, an anisidino group, a diphenylamino group, and an N-methyl-N-phenylamino group.

[0023] Examples of the monovalent group containing a carbonyl group include a formyl group, an acyl group, a carboxy group, an amide group, an alkoxycarbonyl group, a thiocarboxy group, and a thioester group.

[0024] An acyl group is a substituent in which a carbonyl group is linked to an alkyl group, an alkenyl group, or an aryl group. The total number of carbon atoms (1) derived from the carbonyl group of the acyl group and the number of carbon atoms derived from the alkyl group, alkenyl group, or aryl group is preferably 2 to 20, more preferably 2 to 10, and even more preferably 2 to 6. Examples of the acyl group include an acetyl group, a propionyl group, a butylcarbonyl group, a vinylcarbonyl group, and a benzoyl group.

[0025] The amide group is an amide group without a substituent on the nitrogen atom (-CONH ２ ) and an amide group in which some or all of the hydrogen atoms bonded to the nitrogen atom have been substituted with carbon atoms. The number of carbon atoms in the amide group, calculated as the total of the number of carbon atoms (1) derived from the carbonyl group and the number of carbon atoms substituted on the nitrogen atom, is preferably 1 to 20, more preferably 1 to 10, and even more preferably 1 to 5. Examples of the amide group include an unsubstituted amide group, an N-methylamide group, an N-ethylamide group, an N-phenylamide group, an N,N-dimethylamide group, and an N-methyl-N-phenylamide group.

[0026] An alkoxycarbonyl group is a substituent in which a carbonyl group and an alkoxy group are linked together, and is also called an ester group. The total number of carbon atoms (1) derived from the carbonyl group and the number of carbon atoms derived from the alkoxy group is preferably 2 to 20, more preferably 2 to 10, and even more preferably 2 to 6. Examples of the alkoxycarbonyl group include a methoxycarbonyl group, an ethoxycarbonyl group, a butoxycarbonyl group, and a phenoxycarbonyl group.

[0027] A thioester group is a substituent in which a carbonyl group is linked to an alkylthio group or an arylthio group. The total number of carbon atoms (1) derived from the carbonyl group and the number of carbon atoms derived from the alkylthio group or arylthio group is preferably 2 to 20, more preferably 2 to 10, and even more preferably 2 to 6. Examples of thioester groups include a methylthiocarbonyl group, an ethylthiocarbonyl group, a butylthiocarbonyl group, and a phenylthiocarbonyl group.

[0028] The monovalent group containing a carbonyl group may also be a substituent in which one or more hydrogen atoms of an alkyl group are substituted with a carbonyl group, such as a 2-acetoxyethyl group, a 2-acetoethyl group, or a 2-(acetoacetoxy)ethyl group.

[0029] The alkylthio group is preferably an alkylthio group having 1 to 20 carbon atoms, more preferably an alkylthio group having 1 to 10 carbon atoms, and even more preferably an alkylthio group having 1 to 5 carbon atoms. Examples of the alkylthio group include a methylthio group, an ethylthio group, a propylthio group, and an isopropylthio group.

[0030] The arylthio group is preferably an arylthio group having 1 to 20 carbon atoms, more preferably an arylthio group having 3 to 10 carbon atoms, and even more preferably an arylthio group having 6 to 10 carbon atoms. Examples of the arylthio group include a phenylthio group and a tolylthio group.

[0031] R １ and R ２ , R ２ and R ３ , R ３ and R ４ may be linked to each other to form a ring. １ and R ２ Examples of compounds in which R are linked to form a ring include methyl 2-cyclohexylidenepropionate and methyl 2-cyclopentylidenepropionate. ２ and R ３Examples of compounds in which R are linked to form a ring include methyl 1-cyclohexene-1-carboxylate and methyl 1-cyclopentene-1-carboxylate. ３ and R ４ Examples of compounds in which the groups are linked to form a ring include α-methylene-δ-valerolactone and α-methylene-γ-butyrolactone.

[0032] Among the compounds that satisfy the above conditions, from the viewpoint of quality stability during storage of the methyl methacrylate-containing composition, the following compounds are preferred as component A1: methyl acrylate, butyl acrylate, ethyl methacrylate, methyl crotonate, cis-methyl crotonate, isobutyl methacrylate, butyl methacrylate, propyl methacrylate, isopentyl methacrylate, methyl 2-methylene-3-butenoate, methyl 3,3-dimethylacrylate, methyl 2-ethylacrylate, methyl 2-pentenoate, methyl cinnamate, and methyl 3-methoxyacrylate. methyl acrylate, dimethyl fumarate, methacrylamide, acrylic acid, methacrylic acid, crotonic acid, cis-crotonic acid, 3,3-dimethylacrylic acid, 2-ethylacrylic acid, 2-methylene-3-butenoic acid, trans-3-hexen-2-one, isopropenyl methyl ketone, methyl 2-cyclohexylidenepropionate, methyl 2-cyclopentylidenepropionate, methyl 1-cyclohexene-1-carboxylate, methyl 1-cyclopentene-1-carboxylate, α-methylene-δ-valerolactone, α-methylene-γ-butyl Lactone or isopropenyl methyl ketone is preferred, and methyl acrylate, butyl acrylate, ethyl methacrylate, methyl crotonate, cis-methyl crotonate, isobutyl methacrylate, butyl methacrylate, propyl methacrylate, isopentyl methacrylate, methyl 2-methylene-3-butenoate, methyl 3,3-dimethylacrylate, methyl 2-ethylacrylate, methyl 2-pentenoate, methyl cinnamate, methyl 3-methoxyacrylate, dimethyl fumarate, methyl 1-cyclohexene-1-carboxylate are preferred. More preferred are methyl acrylate, ethyl methacrylate, methyl crotonate, isobutyl methacrylate, butyl methacrylate, propyl methacrylate, isopentyl methacrylate, 3,3-dimethyl methyl acrylate, and isopropenyl methyl ketone.

[0033] Component A1 in the first embodiment of the methyl methacrylate-containing composition according to the present invention may be one type or two or more types.

[0034] (Component B) A first embodiment of the methyl methacrylate-containing composition according to the present invention contains a polymerization inhibitor (component B). In this specification, the term "polymerization inhibitor" refers to a compound that inhibits the polymerization reaction of methyl methacrylate. Examples of polymerization inhibitors include phenolic compounds, quinone compounds, nitrobenzene compounds, N-oxyl compounds, amine compounds, phosphorus-containing compounds, sulfur-containing compounds, iron-containing compounds, copper-containing compounds, and manganese-containing compounds. By including component B, the polymerization reaction of methyl methacrylate via a radical polymerization mechanism can be inhibited during storage of methyl methacrylate. Furthermore, component B can trap the aforementioned hydroxy radicals generated during storage of methyl methacrylate. That is, when a methyl methacrylate-containing composition contains component B in addition to component A1, the amount of hydroxy radicals can be reduced through two different mechanisms: component A1 inhibits the generation of hydroxy radicals, and component B removes the generated hydroxy radicals. Therefore, it is believed that the generation of methyl methacrylate dimers and methyl pyruvate can be efficiently inhibited.

[0035] Examples of the polymerization inhibitor that is a phenolic compound include alkylphenols, hydroxyphenols, aminophenols, nitrophenols, nitrosophenols, alkoxyphenols, and tocopherols.

[0036] Examples of alkylphenols include o-cresol, m-cresol, p-cresol, 2-t-butyl-4-methylphenol, 2,4-dimethyl-6-t-butylphenol, 2,6-di-t-butyl-4-methylphenol, 2-t-butylphenol, 4-t-butylphenol, 2,4-di-t-butylphenol, 2-methyl-4-t-butylphenol, 4-t-butyl-2,6-dimethylphenol, 2,2'-methylene-bis(6-t-butyl-4-methylphenol), 2,2'-methylenebis(4-ethyl-6-t-butylphenol), 4,4'-thiobis(3-methyl-6-t-butylphenol), and 3,5-di-t-butyl-4-hydroxytoluene.

[0037] Examples of hydroxyphenols include hydroquinone, 2-methylhydroquinone, 2-t-butylhydroquinone, 2,5-di-t-butylhydroquinone, 2,6-di-t-butylhydroquinone, 2,5-di-t-amylhydroquinone, 2-t-butylmethoxyhydroquinone, 2,3,5-trimethylhydroquinone, 2,5-dichlorohydroquinone, 1,2-dihydroxybenzene, 2-acetylhydroquinone, 4-methylcatechol, 4-t-butylcatechol, 2-methylresorcinol, 4-methylresorcinol, and 2,3-dihydroxyacetophenone.

[0038] Examples of aminophenols include o-aminophenol, m-aminophenol, p-aminophenol, 2-(N,N-dimethylamino)phenol, and 4-(ethylamino)phenol.

[0039] Examples of nitrophenols include o-nitrophenol, m-nitrophenol, p-nitrophenol, 2,4-dinitrophenol, etc. Examples of nitrosophenols include o-nitrosophenol, m-nitrosophenol, p-nitrosophenol, α-nitroso-β-naphthol, etc.

[0040] Examples of alkoxyphenols include 2-methoxyphenol, 2-ethoxyphenol, 2-isopropoxyphenol, 2-t-butoxyphenol, 4-methoxyphenol, 4-ethoxyphenol, 4-propoxyphenol, 4-butoxyphenol, 4-t-butoxyphenol, 4-heptoxyphenol, hydroquinone monobenzyl ether, t-butyl-4-methoxyphenol, di-t-butyl-4-methoxyphenol, pyrogallol-1,2-dimethyl ether, and hydroquinone monobenzoate.

[0041] Examples of tocopherols include α-tocopherol and 2,3-dihydro-2,2-dimethyl-7-hydroxybenzofuran.

[0042] Examples of the polymerization inhibitor that is a quinone compound include p-benzoquinone, chloro-p-benzoquinone, 2,5-dichloro-p-benzoquinone, 2,6-dichloro-p-benzoquinone, tetrachloro-p-benzoquinone, tetrabromo-p-benzoquinone, 2,3-dimethyl-p-benzoquinone, 2,5-dimethyl-p-benzoquinone, methoxy-p-benzoquinone, and methyl-p-benzoquinone.

[0043] Examples of the polymerization inhibitor that is a nitrobenzene compound include nitrobenzene, o-dinitrobenzene, m-dinitrobenzene, p-dinitrobenzene, 2,4-dinitrotoluene, dinitrodurene, and 2,2-diphenyl-1-picrylhydrazyl.

[0044] Examples of the polymerization inhibitor that is an N-oxyl compound include 4-hydroxy-2,2,6,6-tetramethyl-piperidine-N-oxyl, 4-oxo-2,2,6,6-tetramethyl-piperidine-N-oxyl, 4-acetoxy-2,2,6,6-tetramethyl-piperidine-N-oxyl, 2,2,6,6-tetramethyl-piperidine-N-oxyl, piperidine-1-oxyl, 4-(dimethylamino)-2,2,6,6-tetramethyl-piperidine-N-oxyl, 4-amino-2,2,6,6-tetramethyl-piperidine-N-oxyl, 4-ethanoloxy-2,2,6,6-tetramethyl-piperidine-N-oxyl, and 4-benzoyloxy-2,2,6,6-tetramethylpiperidine-N-oxyl. nitroxide, 2,2,5,5-tetramethyl-piperidine-N-oxyl, 3-amino-2,2,5,5-tetramethyl-piperidine-N-oxyl, 4,4',4''-tris(2,2,6,6-tetramethyl-piperidine-N-oxyl)phosphite, 3-oxo-2,2,5,5-tetramethylpyrrolidine-N-oxyl, pyrrolidine-1-oxyl, 2,2,5,5-tetramethyl-1-oxa-3-azacyclopentyl-3-oxy, 2,2,5,5-tetramethyl-3-pyrrolinyl-1-oxy-3-carboxylic acid, 2,2,3,3,5,5,6,6-octamethyl-1,4-diazacyclohexyl-1,4-dioxy, di-tert-butyl nitroxide, di-tert-amyl nitroxide, and the like.

[0045] Examples of the polymerization inhibitor that is an amine compound include N,N-diphenylamine, alkylated diphenylamine, 4,4'-dicumyl-diphenylamine, 4,4'-dioctyldiphenylamine, 4-aminodiphenylamine, p-nitrosodiphenylamine, N-nitrosodinaphthylamine, N-nitrosodiphenylamine, N-nitrosophenylnaphthylamine, N-nitrosophenylhydroxylamine, N,N'-dialkyl-p-phenylenediamine (the alkyl groups may be the same or different, and each may independently consist of 1 to 4 carbon atoms and may be linear or branched), N,N'-diphenyl-p-phenylenediamine, N-phenyl-N'-isopropyl-p-phenylenediamine, N-(1,3-dimethylbutyl)-N'-phenyl-1,4-phenylenediamine, Examples thereof include N,N'-di-2-naphthyl-p-phenylenediamine, N,N-diethylhydroxylamine, 1,4-benzenediamine, N-(1,4-dimethylpentyl)-N'-phenyl-1,4-benzenediamine, N-(1,3-dimethylbutyl)-N'-phenyl-1,4-benzenediamine, 6-ethoxy-2,2,4-trimethyl-1,2-dihydroquinoline, 2,2,4-trimethyl-1,2-dihydroquinoline polymer, aldol-α-naphthylamine, N-phenyl-β-naphthylamine, 4-hydroxy-2,2,6,6-tetramethylpiperidine, 4-benzoyloxy-2,2,6,6-tetramethylpiperidine, 1,4-dihydroxy-2,2,6,6-tetramethylpiperidine, and 1-hydroxy-4-benzoyloxy-2,2,6,6-tetramethylpiperidine.

[0046] Examples of the polymerization inhibitor that is a phosphorus-containing compound include triphenylphosphine, triphenyl phosphite, triethyl phosphite, tris(isodecyl)phosphite, tris(tridecyl)phosphite, phenyl diisooctyl phosphite, phenyl diisodecyl phosphite, phenyl di(tridecyl)phosphite, diphenyl isooctyl phosphite, diphenyl isodecyl phosphite, diphenyl tridecyl phosphite, phosphonic acid [1,1-diphenyl-4,4'-diylbistetrakis-2,4-bis(1,1-dimethylethyl)phenyl] ester, triphenyl phosphite, tris(nonylphenyl)phosphite, 4,4'-isopropylidenediphenol alkyl phosphite, tris(2,4-di-tert-butylphenyl)phosphite, tris(biphenyl)phosphite, and distearyl phosphite. Pentaerythritol diphosphite, di(2,4-di-tert-butylphenyl)pentaerythritol diphosphite, di(nonylphenyl)pentaerythritol diphosphite, phenyl bisphenol A pentaerythritol diphosphite, tetra(tridecyl)-4,4'-butylidenebis(3-methyl-6-tert-butylphenol) diphosphite, hexa(tridecyl)-1,1,3-tris(2- methyl-4-hydroxy-5-tert-butylphenyl)butane triphosphite, 3,5-di-tert-butyl-4-hydroxybenzyl phosphate diethyl ester, sodium bis(4-tert-butylphenyl)phosphate, sodium 2,2'-methylene-bis(4,6-di-tert-butylphenyl)phosphate, 1,3-bis(diphenoxyphosphonyloxy)benzene, and the like.

[0047] Examples of the polymerization inhibitor that is a sulfur-containing compound include diphenyl sulfide, phenothiazine, 3-oxophenothiazine, 5-oxophenothiazine, phenothiazine dimer, 1,4-dimercaptobenzene, 1,2-dimercaptobenzene, 2-mercaptophenol, 4-mercaptophenol, 2-(methylthio)phenol, 3,7-bis(dimethylamino)phenothiazinium chloride, and sulfur (element).

[0048] The polymerization inhibitor, which is an iron-containing compound, may, for example, be iron (III) chloride.

[0049] Examples of the polymerization inhibitor that is a copper-containing compound include copper dimethyldithiocarbamate, copper diethyldithiocarbamate, copper dibutyldithiocarbamate, copper salicylate, copper acetate, copper thiocyanate, copper nitrate, copper chloride, copper carbonate, copper hydroxide, copper acrylate, and copper methacrylate.

[0050] Examples of the polymerization inhibitor that is a manganese-containing compound include manganese dialkyldithiocarbamate (the alkyl groups are any of methyl, ethyl, propyl, and butyl groups, and may be the same or different), manganese diphenyldithiocarbamate, manganese formate, manganese acetate, manganese octanoate, manganese naphthenate, manganese permanganate, and manganese salts of ethylenediaminetetraacetic acid.

[0051] Among the above, from the viewpoint of quality stability during storage of the methyl methacrylate-containing composition, Component B is preferably at least one polymerization inhibitor selected from the group consisting of phenolic compounds, N-oxyl compounds, amine compounds, phosphorus-containing compounds, and sulfur-containing compounds, and more preferably at least one polymerization inhibitor selected from the group consisting of hydroquinone, 4-methoxyphenol, 2,4-dimethyl-6-t-butylphenol, 2,6-di-t-butyl-4-methylphenol, 4-hydroxy-2,2,6,6-tetramethylpiperidine-N-oxyl, N,N-diphenylamine, N-nitrosodiphenylamine, triphenyl phosphite, and phenothiazine.

[0052] Component B may be one type or two or more types. When a methyl methacrylate-containing composition contains a compound that corresponds to both component A1 and component B, the compound is considered to be component B. In other words, the methyl methacrylate-containing composition must contain a component A1 that is different from the compound. When two or more compounds that correspond to both component A1 and component B are contained, the compound with the highest molar concentration in the methyl methacrylate composition is considered to be component B, and the other compounds are considered to be component A1.

[0053] (Concentration of Component A1 and Component B) When the concentration of Component A1 is MA1 (µmol / L) and the concentration of Component B is MB (µmol / L), from the viewpoint of the efficiency of inhibiting the production of methyl pyruvate, MB / MA1 is preferably 0.1 or more. There is no particular upper limit to MB / MA1, but it is usually 100 or less.

[0054] MA1 is preferably 1 to 85,000 μmol / L. By having MA1 at 1 μmol / L or more, the effect of suppressing the production of methyl methacrylate dimers and methyl pyruvate can be sufficiently obtained. Furthermore, by having MA1 at 85,000 μmol / L or less, the amount of impurities when a methyl methacrylate polymer is produced by polymerization of the methyl methacrylate-containing composition according to the present invention can be reduced, preventing adverse effects on the physical properties of the polymer. The lower limit of MA1 is more preferably 10 μmol / L or more, and even more preferably 50 μmol / L or more. Furthermore, the upper limit of MA1 is more preferably 40,000 μmol / L or less, even more preferably 20,000 μmol / L or less, and particularly preferably 15,000 μmol / L or less.

[0055] The MB is preferably 1 to 7000 μmol / L. By having an MB of 1 μmol / L or more, the effect of suppressing the production of methyl methacrylate dimers and methyl pyruvate can be sufficiently obtained. Furthermore, by having an MB of 7000 μmol / L or less, the amount of impurities when a methyl methacrylate polymer is produced by polymerization of the methyl methacrylate-containing composition according to the present invention can be reduced, preventing adverse effects on the physical properties of the polymer. The lower limit of MB is more preferably 10 μmol / L or more, and even more preferably 40 μmol / L or more. Furthermore, the upper limit of MB is more preferably 5000 μmol / L or less, and even more preferably 1000 μmol / L or less.

[0056] (Methyl methacrylate concentration) In the first embodiment, the methyl methacrylate concentration of the methyl methacrylate-containing composition according to the present invention is 99 to 99.99% by mass. By having a methyl methacrylate concentration of 99% by mass or more, the amount of impurities produced when a methyl methacrylate polymer is produced by polymerization of the methyl methacrylate-containing composition can be reduced, preventing adverse effects on the physical properties of the polymer. Furthermore, by having a methyl methacrylate concentration of 99.99% by mass or less, purification costs can be reduced. The lower limit of the methyl methacrylate concentration is preferably 99.8% by mass or more.

[0057] (Component C) The first aspect of the methyl methacrylate-containing composition according to the present invention may contain another compound (component C) as long as the concentration of methyl methacrylate is 99 to 99.99% by mass. Examples of component C include impurities generated during the production of methyl methacrylate. For example, methyl methacrylate may contain diacetyl as an impurity. From the viewpoint of reducing coloration of the methyl methacrylate-containing composition, the concentration of diacetyl is preferably 55 μmol / L or less, more preferably 20 μmol / L or less, even more preferably 10 μmol / L or less, and particularly preferably 1 μmol / L.

[0058] (Analysis of Methyl Methacrylate-Containing Composition) The presence of component A1, component B, component C, and water in a methyl methacrylate-containing composition can be confirmed, for example, by GC-MS measurement. If a GC-MS chart of the methyl methacrylate-containing composition has a peak at the same retention time as an authentic sample of component A1, and the m / z value detected in the mass spectrum of the peak matches the exact mass of component A1, the methyl methacrylate-containing composition can be determined to contain component A1. If an authentic sample of component A1 is not available, the peak can be determined to be a component A1 peak if the mass spectrum pattern of the peak appearing in the GC-MS chart of the methyl methacrylate-containing composition matches the mass spectrum pattern of component A1 recorded in a mass spectrum database. In other words, it can be determined that the methyl methacrylate-containing composition contains component A1. Examples of mass spectrum databases include NIST20, NIST17, NIST14, and NIST14s. Furthermore, when the volatility is low and detection by GC-MS measurement is not possible, detection can be performed using LC-MS. The presence of components B, C, and water can also be confirmed by a similar method. The concentration of methyl methacrylate can be calculated, for example, by performing GC-FID measurement of a methyl methacrylate-containing composition, quantifying the concentration using the area percentage method, and correcting the result using the water concentration quantified with a Karl Fischer moisture meter. The concentration of component A1 can be calculated, for example, by performing GC measurement of a methyl methacrylate-containing composition and quantifying the concentration using the internal standard method. If a standard sample of component A1 is not available and quantification by the internal standard method is not possible, GC-FID measurement of any organic compound with a known concentration can be performed under the same conditions as the methyl methacrylate-containing composition, and the concentration of component A1 can be calculated using the following formula: Here, N is the number of carbon atoms contained in one molecule of an organic compound with a known concentration, N Ａ１ is the number of carbon atoms contained in one molecule of component A1, S Ａ１is the peak area of ​​component A1, S is the peak area of ​​the organic compound of known concentration, and M is the concentration (μmol / L) of the organic compound of known concentration. Furthermore, if the volatility is low and quantification by GC measurement is not possible, quantification can be performed using a chromatography method such as LC. The concentrations of components B and C can also be calculated using the same method as for component A1 above. Furthermore, the presence of water in the methyl methacrylate-containing composition and its concentration can be confirmed by the Karl Fischer method.

[0059] [Methyl methacrylate-containing composition 2] A second aspect of the methyl methacrylate-containing composition according to the present invention is a methyl methacrylate-containing composition comprising methyl methacrylate and an α,β-unsaturated carboxylic acid ester (component A2) represented by the following formula (2), wherein the concentration of methyl methacrylate is 99 to 99.99 mass %. Furthermore, when the concentration of component A2 is MA2 (μmol / L), MA2 is 1 to 40,000 μmol / L.

[0060] In the above formula (2), R ５ , R ６ and R ７ R each independently represents a hydrogen atom, an alkyl group, an alkenyl group, an aryl group, a hydroxy group, an alkoxy group, an amino group, a monovalent group containing a carbonyl group, an alkylthio group, or an arylthio group. ８ represents an alkyl group, an alkenyl group, or an aryl group. ５ and R ６ , R ６ and R ７ , R ７ and R ８ may be linked to each other to form a ring. ５ = H, and R ６ = H, and R ７ =CH ３ and R ８ =CH ３This excludes the case where the α,β-unsaturated carbonyl compound represented by formula (2) is methyl methacrylate. H represents a hydrogen atom, C represents a carbon atom, and O represents an oxygen atom. The methyl methacrylate-containing composition may also contain component B, component C, and water, as long as the concentration of methyl methacrylate satisfies 99 to 99.99% by mass. Each item will be described in detail below.

[0061] (Component A2) A second aspect of the methyl methacrylate-containing composition according to the present invention comprises an α,β-unsaturated carboxylic acid ester (component A2) represented by the formula (2). When the methyl methacrylate-containing composition contains component A2, the amount of ultraviolet light that can be absorbed by one molecule of component A2 is large, and the generation of hydroxy radicals can be sufficiently suppressed. Therefore, even in the absence of component B, which traps the generated hydroxy radicals, the generation of methyl methacrylate dimers and methyl pyruvate can be suppressed. On the other hand, from the viewpoint of further suppressing the generation of methyl methacrylate dimers and methyl pyruvate, it is preferable that the methyl methacrylate-containing composition contains component B.

[0062] The molecular weight of Component A2 is preferably 1000 or less. By having a molecular weight of 1000 or less, the number of conjugated double bonds per unit mass can be increased, and the effects of the present invention can be obtained with a small weight. The molecular weight of Component A2 is more preferably 800 or less, even more preferably 600 or less, and particularly preferably 400 or less.

[0063] R in the formula (2) ５ , R ６ and R ７ each independently represents a hydrogen atom, an alkyl group, an alkenyl group, an aryl group, a hydroxy group, an alkoxy group, an amino group, a monovalent group containing a carbonyl group, an alkylthio group, or an arylthio group. ８ represents an alkyl group, an alkenyl group, or an aryl group. ５ , R ６ , R ７ and R ８ may be the same or different.

[0064] R ５、 R ６ 、 R ７ and R ８ When R satisfies the above condition, the π-conjugated system of component A2 is maintained, and therefore the compound has the property of absorbing ultraviolet light over a wide wavelength range, thereby achieving the effects of the present invention. ５ , R ６ and R ７ is preferably a hydrogen atom, an alkyl group having 1 to 5 carbon atoms, an alkenyl group having 2 to 5 carbon atoms, an aryl group having 1 to 12 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, an amino group, a monovalent group containing a carbonyl group, or an alkylthio group having 1 to 5 carbon atoms. These are highly stable substituents, and can prevent Component A2 from changing into other compounds during storage. Furthermore, when Component A2 has these substituents, the amount of ultraviolet light that can be absorbed by one molecule of Component A2 is sufficient. ５ , R ６ and R ７ is more preferably a hydrogen atom or an alkyl group having 1 to 5 carbon atoms, and even more preferably a hydrogen atom, a methyl group, an ethyl group, an n-propyl group, or an isopropyl group. ８ is preferably an alkyl group having 1 to 5 carbon atoms, an alkenyl group having 2 to 5 carbon atoms, or an aryl group having 1 to 12 carbon atoms. These are highly stable substituents, and can prevent component A2 from changing into other compounds during storage. ８ R is more preferably an alkyl group having 1 to 5 carbon atoms, further preferably a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, an isobutyl group, or an isopentyl group, and particularly preferably a methyl group. ８ When the structure is as described above, the quality stability of the methyl methacrylate-containing composition during storage can be improved.

[0065] Preferred forms of the alkyl group, alkenyl group, aryl group, hydroxy group, alkoxy group, amino group, monovalent group containing a carbonyl group, alkylthio group, or arylthio group in the formula (2) are the same as those in the formula (1).

[0066] R ５ and R ６, R ６ and R ７ , R ７ and R ８ may be linked to each other to form a ring. ５ and R ６ Examples of compounds in which R are linked to form a ring include methyl 2-cyclohexylidenepropionate and methyl 2-cyclopentylidenepropionate. ６ and R ７ Examples of compounds in which R are linked to form a ring include methyl 1-cyclohexene-1-carboxylate and methyl 1-cyclopentene-1-carboxylate. ７ and R ８ Examples of compounds in which the groups are linked to form a ring include α-methylene-δ-valerolactone and α-methylene-γ-butyrolactone.

[0067] Among the compounds satisfying the above conditions, from the viewpoint of quality stability during storage of the methyl methacrylate-containing composition, examples of component A2 include methyl acrylate, butyl acrylate, ethyl methacrylate, methyl crotonate, cis-methyl crotonate, isobutyl methacrylate, butyl methacrylate, propyl methacrylate, isopentyl methacrylate, methyl 2-methylene-3-butenoate, methyl 3,3-dimethylacrylate, methyl 2-ethylacrylate, methyl 2-pentenoate, methyl cinnamate, methyl 3-methoxyacrylate, dimethyl fumarate, methyl 2-cyclohexylidenepropionate, methyl 2-cyclopentylidenepropionate, methyl 1-cyclohexene-1-carboxylate ... Methyl 2-cyclohexene-1-carboxylate, α-methylene-δ-valerolactone, or α-methylene-γ-butyrolactone is preferred, and methyl acrylate, butyl acrylate, ethyl methacrylate, methyl crotonate, cis-methyl crotonate, isobutyl methacrylate, butyl methacrylate, propyl methacrylate, isopentyl methacrylate, methyl 2-methylene-3-butenoate, methyl 3,3-dimethylacrylate, methyl 2-ethylacrylate, methyl 2-pentenoate, methyl cinnamate, methyl 3-methoxyacrylate, dimethyl fumarate, or methyl 1-cyclohexene-1-carboxylate is even more preferred, with methyl acrylate, ethyl methacrylate, or methyl crotonate being even more preferred.

[0068] Component A2 in the second embodiment of the methyl methacrylate-containing composition according to the present invention may be one type or two or more types.

[0069] (Component B) When the methyl methacrylate-containing composition contains component B, the preferred embodiment of component B is the same as in the first embodiment. Component B may be one type or two or more types. When the methyl methacrylate-containing composition contains a compound corresponding to both component A2 and component B, the compound is considered to be component A2. In other words, when the methyl methacrylate-containing composition contains component A2 and component B, this means that the composition contains a component B that is different from the compound A2. When the composition contains two or more compounds corresponding to both component A2 and component B, the compound with the highest molar concentration in the methyl methacrylate composition is considered to be component A2, and the other compounds are considered to be component B.

[0070] (Concentration of Component A2 and Component B) From the viewpoint of the efficiency of inhibiting the production of methyl pyruvate, MB / MA2 is preferably 0.1 or more. There is no particular upper limit to MB / MA2, but it is usually 100 or less.

[0071] MA2 is 1 to 40,000 μmol / L. When MA2 is 1 μmol / L or more, the effect of suppressing the production of methyl methacrylate dimer and methyl pyruvate can be sufficiently obtained. Furthermore, when MA2 is 40,000 μmol / L or less, the amount of impurities when a methyl methacrylate polymer is produced by polymerization of the methyl methacrylate-containing composition according to the present invention can be reduced, preventing adverse effects on the physical properties of the polymer. The lower limit of MA2 is more preferably 10 μmol / L or more, and even more preferably 50 μmol / L or more. Furthermore, the upper limit of MA2 is more preferably 10,000 μmol / L or less, even more preferably 5,000 μmol / L or less, and most preferably 500 μmol / L or less.

[0072] The preferred embodiment of the MB is the same as that of the first embodiment.

[0073] (Concentration of Methyl Methacrylate) The preferred embodiment of the concentration of methyl methacrylate is the same as that in the first embodiment.

[0074] (Component C) A preferred embodiment of component C is the same as that of the first embodiment.

[0075] (Analysis of methyl methacrylate-containing composition) The method for confirming that the methyl methacrylate-containing composition contains Component A2, Component B, Component C, and water, and the method for measuring the concentrations of methyl methacrylate, Component A2, Component B, Component C, and water are the same as those in the first embodiment.

[0076] [Methyl methacrylate-containing composition 3] A third aspect of the methyl methacrylate-containing composition according to the present invention is a composition containing methyl methacrylate and one or more of methyl acrylate, butyl acrylate, ethyl methacrylate, methyl crotonate, cis-methyl crotonate, isobutyl methacrylate, butyl methacrylate, propyl methacrylate, isopentyl methacrylate, methyl 2-methylene-3-butenoate, methyl 3,3-dimethylacrylate, methyl 2-ethylacrylate, methyl 2-pentenoate, methyl cinnamate, methyl 3-methoxyacrylate, A methyl methacrylate-containing composition comprising at least one compound (Component A3) selected from the group consisting of dimethyl fumarate, methyl 1-cyclohexene-1-carboxylate, methacrylamide, acrylic acid, crotonic acid, cis-crotonic acid, 3,3-dimethylacrylic acid, 2-ethylacrylic acid, 2-methylene-3-butenoic acid, and trans-3-hexen-2-one, wherein the methyl methacrylate-containing composition has a concentration of 99 to 99.99% by mass. Furthermore, when the concentration of Component A3 is MA3 (μmol / L), MA3 is 1 to 40,000 μmol / L. Furthermore, the methyl methacrylate-containing composition may contain Component B, Component C, and water, as long as the methyl methacrylate concentration satisfies the range of 99 to 99.99% by mass. Each item will be described in detail below.

[0077] (Component A3) A third aspect of the methyl methacrylate-containing composition according to the present invention comprises at least one compound (Component A3) selected from the group consisting of methyl acrylate, butyl acrylate, ethyl methacrylate, methyl crotonate, cis-methyl crotonate, isobutyl methacrylate, butyl methacrylate, propyl methacrylate, isopentyl methacrylate, methyl 2-methylene-3-butenoate, methyl 3,3-dimethylacrylate, methyl 2-ethylacrylate, methyl 2-pentenoate, methyl cinnamate, methyl 3-methoxyacrylate, dimethyl fumarate, methyl 1-cyclohexene-1-carboxylate, methacrylamide, acrylic acid, crotonic acid, cis-crotonic acid, 3,3-dimethylacrylic acid, 2-ethylacrylic acid, 2-methylene-3-butenoic acid, and trans-3-hexen-2-one. When the methyl methacrylate-containing composition contains Component A3, the amount of ultraviolet light that can be absorbed by one molecule of Component A3 is large, and the generation of hydroxyl radicals can be sufficiently suppressed. Therefore, even without Component B, which traps the generated hydroxyl radicals, the generation of methyl methacrylate dimers and methyl pyruvate can be suppressed. On the other hand, from the viewpoint of further suppressing the generation of methyl methacrylate dimers and methyl pyruvate, it is preferable that the methyl methacrylate-containing composition contains Component B.

[0078] The molecular weight of Component A3 is preferably 200 or less. A molecular weight of 200 or less allows the number of conjugated double bonds per unit mass to be increased, and therefore the effects of the present invention can be obtained with a small weight. The molecular weight of Component A3 is more preferably 150 or less, even more preferably 130 or less, and particularly preferably 110 or less.

[0079] Component A3 is preferably at least one selected from the group consisting of methyl acrylate, methyl crotonate, acrylic acid, and crotonic acid.

[0080] Component A3 in the third embodiment of the methyl methacrylate-containing composition according to the present invention may be one type or two or more types.

[0081] (Component B) When the methyl methacrylate-containing composition contains component B, the preferred embodiment of component B is the same as in the first embodiment. Component B may be one type or two or more types. When the methyl methacrylate-containing composition contains a compound corresponding to both component A3 and component B, the compound is considered to be component A3. In other words, when the methyl methacrylate-containing composition contains component A3 and component B, this means that the composition contains a component B that is different from the compound A3. When the composition contains two or more compounds corresponding to both component A3 and component B, the compound with the highest molar concentration in the methyl methacrylate composition is considered to be component A3, and the other compounds are considered to be component B.

[0082] (Concentration of Component A3 and Component B) From the viewpoint of the efficiency of inhibiting the production of methyl pyruvate, MB / MA3 is preferably 0.1 or more. There is no particular upper limit to MB / MA3, but it is usually 100 or less.

[0083] MA3 is 1 to 40,000 μmol / L. When MA3 is 1 μmol / L or more, the effect of suppressing the production of methyl methacrylate dimers and methyl pyruvate can be sufficiently obtained. Furthermore, when MA2 is 40,000 μmol / L or less, the amount of impurities when a methyl methacrylate polymer is produced by polymerization of the methyl methacrylate-containing composition according to the present invention can be reduced, preventing adverse effects on the physical properties of the polymer. The lower limit of MA3 is more preferably 10 μmol / L or more, and even more preferably 50 μmol / L or more. Furthermore, the upper limit of MA3 is more preferably 10,000 μmol / L or less, even more preferably 5,000 μmol / L or less, and most preferably 500 μmol / L or less.

[0084] The preferred embodiment of the MB is the same as that of the first embodiment.

[0085] (Concentration of Methyl Methacrylate) The preferred embodiment of the concentration of methyl methacrylate is the same as that in the first embodiment.

[0086] (Component C) A preferred embodiment of component C is the same as that of the first embodiment.

[0087] (Analysis of methyl methacrylate-containing composition) The method for confirming that the methyl methacrylate-containing composition contains Component A3, Component B, Component C, and water, and the method for measuring the concentrations of methyl methacrylate, Component A3, Component B, Component C, and water are the same as those in the first embodiment.

[0088] [Method for Producing Methyl Methacrylate-Containing Composition] Examples of methods for producing a methyl methacrylate-containing composition according to the present invention include a method in which component A1, component A2, or component A3 (hereinafter collectively referred to as "component A") and component B are added to methyl methacrylate. Commercially available methyl methacrylate may be used, or methyl methacrylate produced by a known method such as the acetone cyanohydrin (ACH) method, the new acetone cyanohydrin (new ACH) method, the C4 direct oxidation method, the direct methacrylate method, the ethylene method, or the new ethylene method may be used. Components A and B may be commercially available products, or products synthesized by a known method may be used. When methyl methacrylate produced by a known method such as the acetone cyanohydrin (ACH) method, the new acetone cyanohydrin (new ACH) method, the C4 direct oxidation method, the direct methacrylate method, the ethylene method, or the new ethylene method is used, component A or component B may be added as a raw material or during the production process to produce a methyl methacrylate-containing composition. Furthermore, when component A or component B is produced as a by-product in the process for producing methyl methacrylate, a methyl methacrylate-containing composition may be produced by retaining a portion of the produced component A or component B.

[0089] [Method for Evaluating Storage Stability and Thermal Stability] The methyl methacrylate-containing composition according to the present invention has high quality stability during storage. Examples of methods for evaluating the quality stability of a methyl methacrylate-containing composition during storage include, for example, actually storing the methyl methacrylate-containing composition for a long period of time and confirming the amounts of methyl methacrylate dimer and methyl pyruvate produced. From the viewpoint of ease of operation, a method may also be used in which the methyl methacrylate-containing composition is heated for a short period of time and the amounts of methyl methacrylate dimer and methyl pyruvate produced are confirmed. When heating for a short period of time, the heating temperature is preferably 50 to 100°C, and the heating time is preferably 1 to 24 hours. In the present invention, the quality stability of a methyl methacrylate-containing composition during storage is evaluated based on the amounts of methyl methacrylate dimer and methyl pyruvate produced when the methyl methacrylate-containing composition is stored at 25°C for 14 days.

[0090] [Method for Producing Methyl Methacrylate Polymer] The method for producing a methyl methacrylate polymer according to the present invention includes a step of polymerizing a polymerizable composition containing the methyl methacrylate-containing composition according to the present invention.

[0091] <Polymerizable Composition> The polymerizable composition may contain a monomer copolymerizable with methyl methacrylate and other additives, if necessary.

[0092] (Monomer Copolymerizable with Methyl Methacrylate) Examples of the monomer copolymerizable with methyl methacrylate include the following.Methacrylic acid esters such as ethyl methacrylate, isopropyl methacrylate, n-butyl methacrylate, isobutyl methacrylate, tert-butyl methacrylate, 2-ethylhexyl methacrylate, phenyl methacrylate, or benzyl methacrylate; acrylic acid esters such as methyl acrylate, ethyl acrylate, n-butyl acrylate, isobutyl acrylate, tert-butyl acrylate, or 2-ethylhexyl acrylate; unsaturated carboxylic acids such as acrylic acid, methacrylic acid, maleic acid, or itaconic acid; unsaturated carboxylic acid anhydrides such as maleic anhydride or itaconic anhydride; maleimides such as N-phenylmaleimide or N-cyclohexylmaleimide; hydroxy group-containing vinyl monomers such as 2-hydroxyethyl acrylate, 2-hydroxyethyl methacrylate, or 2-hydroxypropyl methacrylate; vinyl esters such as vinyl acetate or vinyl benzoate; vinyl chloride, vinylidene chloride, and derivatives thereof; nitrogen-containing vinyl monomers such as methacrylamide or acrylonitrile; epoxy group-containing monomers such as glycidyl acrylate or glycidyl methacrylate; aromatic vinyl monomers such as styrene or α-methylstyrene; alkanediol di(meth)acrylates such as ethylene glycol di(meth)acrylate, 1,2-propylene glycol di(meth)acrylate, 1,3-butylene glycol di(meth)acrylate, or 1,6-hexanediol di(meth)acrylate; polyoxyalkylene glycol di(meth)acrylates such as diethylene glycol di(meth)acrylate, dipropylene glycol di(meth)acrylate, triethylene glycol (meth)acrylate, tetraethylene glycol di(meth)acrylate, polyethylene glycol di(meth)acrylate, or neopentyl glycol di(meth)acrylate; vinyl monomers having two or more ethylenically unsaturated bonds in the molecule, such as divinylbenzene; An unsaturated polyester prepolymer obtained from at least one polycarboxylic acid including an ethylenically unsaturated polycarboxylic acid and at least one diol; a vinyl ester prepolymer obtained by acrylic-modifying the terminal epoxy group;

[0093] Among the above, the monomer copolymerizable with methyl methacrylate is preferably at least one selected from the group consisting of methacrylic acid esters and acrylic acid esters. By polymerizing the polymerizable composition, a methyl methacrylate polymer having an excellent balance of transparency, heat resistance, and moldability can be obtained. The monomer copolymerizable with methyl methacrylate is more preferably an acrylic acid ester, and particularly preferably at least one selected from the group consisting of methyl acrylate, ethyl acrylate, and n-butyl acrylate.

[0094] The monomer copolymerizable with methyl methacrylate may be one type or two or more types. When Component A is a monomer copolymerizable with methyl methacrylate, Component A may be used as a monomer copolymerizable with methyl methacrylate, or a monomer copolymerizable with methyl methacrylate may be used separately from Component A.

[0095] In the polymerizable composition, the lower limit of the content of the monomer copolymerizable with methyl methacrylate is preferably 0.01 parts by mass or more per 100 parts by mass of methyl methacrylate. This allows for the production of a highly transparent methyl methacrylate polymer. The upper limit of the content of the monomer copolymerizable with methyl methacrylate is preferably 50 parts by mass or less, more preferably 40 parts by mass or less, and even more preferably 30 parts by mass or less per 100 parts by mass of methyl methacrylate. The lower limit of the content of the monomer copolymerizable with methyl methacrylate is more preferably 0.1 parts by mass or more, even more preferably 1 part by mass or more per 100 parts by mass of methyl methacrylate.

[0096] (Other Additives) The other additives preferably include a polymerization initiator. If necessary, a chain transfer agent, a release agent, a lubricant, a plasticizer, an antioxidant, an antistatic agent, a light stabilizer, an ultraviolet absorber, a flame retardant, a flame retardant aid, a polymerization inhibitor, a filler, a pigment, a dye, a silane coupling agent, a leveling agent, an antifoaming agent, a fluorescent agent, etc. The other additives may be one type or two or more types.

[0097] Examples of the polymerization initiator include the following: azo compounds such as 2,2'-azobisisobutyronitrile, 2,2'-azobis(2-methylbutyronitrile), 2,2'-azobis(2-methylpropionitrile), 2,2'-azobis(2,4-dimethylvaleronitrile), 2,2'-azobis(2,4,4-trimethylpentane), 2,2'-azobis(2-methylpropane), 1,1'-azobis(cyclohexanecarbonitrile), and dimethyl-2,2'-azobisisobutyrate; Benzoyl peroxide, 2,5-dimethyl-2,5-bis(t-butylperoxy)hexane, 1,1-bis(t-butylperoxy)cyclohexane, 1,1-bis(t-butylperoxy)-3,5,5-trimethylcyclohexane, t-butylperoxy-2-ethylhexanoate, t-butylperoxyisobutyrate, t-butylperoxybenzoate, t-hexylperoxybenzoate, t-butylperoxyisopropyl monocarbonate, t-butylperoxy-3,5,5-trimethylhexanoate, t-butylperoxylaurate, t-butylperoxyacetate, t-hexylperoxyisopropyl monocarbonate, t-hexylperoxy organic peroxides such as 1,1,3,3-tetramethylbutylperoxyethylhexanoate, 1,1,2-trimethylpropylperoxy-2-ethylhexanoate, 1,1,3,3-tetramethylbutylperoxyisopropyl monocarbonate, 1,1,2-trimethylpropylperoxyisopropyl monocarbonate, 1,1,3,3-tetramethylbutylperoxyisonononaate, 1,1,2-trimethylpropylperoxyisonononaate, di-t-butyl peroxide, di-t-hexyl peroxide, lauroyl peroxide, and dilauroyl peroxide; persulfate compounds such as potassium persulfate; redox polymerization initiators;

[0098] Among the above, from the viewpoints of storage stability and reactivity with methyl methacrylate, the polymerization initiator is preferably at least one selected from the group consisting of azo compounds and organic peroxides. The amount of the polymerization initiator used is preferably 0.0001 to 1 part by mass per 100 parts by mass of the total of methyl methacrylate and the monomer copolymerizable with methyl methacrylate.

[0099] <Polymerization method for polymerizable composition> Examples of the polymerization method include bulk polymerization, solution polymerization, emulsion polymerization, and suspension polymerization. Bulk polymerization is preferred from the viewpoints of the environmental load caused by the use of solvents and the transparency of the resulting methyl methacrylate polymer.

[0100] The specific means for the bulk polymerization method is not particularly limited, and the polymerizable composition can be produced using known cast polymerization methods such as cell casting or continuous casting. Cast polymerization is a method in which a polymerizable composition is injected into a mold consisting of two inorganic glass or metal plates (e.g., SUS plates) arranged opposite each other at a predetermined distance and sealed at the periphery with a gasket such as a soft resin tube, and polymerized to obtain a methyl methacrylate polymer. The mold used for cast polymerization is not particularly limited, and known molds can be used. Examples of cell casting molds include those in which two plates, such as inorganic glass plates, chrome-plated metal plates, or stainless steel plates, are arranged opposite each other at a predetermined distance, with gaskets placed on their edges to form a sealed space between the plates and the gasket. Examples of continuous casting molds include those in which a sealed space is formed between the opposing surfaces of a pair of endless belts running in the same direction at the same speed, and gaskets running at the same speed as the endless belts on both side edges of the endless belts.

[0101] The gap between the molds is adjusted as needed to obtain a resin plate of the desired thickness, but is generally 1 to 30 mm. The polymerization temperature is preferably 125 to 210°C. This allows for an appropriate polymerization rate. The lower limit of the polymerization temperature is more preferably 130°C or higher, and the upper limit is more preferably 180°C or lower. The polymerization time is not particularly limited, and can be, for example, 0.5 to 24 hours.

[0102] The present invention will be described in detail below with reference to examples and comparative examples, but the present invention is not limited to these examples. In the examples and comparative examples, "%" and "ppm" mean "% by weight" and "ppm by weight" unless otherwise specified. The water concentration contained in the methyl methacrylate reagent was calculated by the Karl Fischer method. The composition of the components of the methyl methacrylate-containing composition before storage was calculated from the amount of each raw material added. The methyl methacrylate dimer and methyl pyruvate in the methyl methacrylate-containing composition after storage were quantified using GC-MS by the absolute calibration curve method. The GC-MS measurement conditions are shown below. Apparatus: GC-MS measurement apparatus (product name: QP-2010SE, manufactured by Shimadzu Corporation)

[0103] [GC conditions] Column (product name: DB-WAX, manufactured by Agilent Technologies) Length: 60 m, inner diameter: 0.32 mm, film thickness: 1.00 μm Injection volume: 1.0 μL Vaporizer temperature: 210°C Column oven temperature: 35°C for 10 minutes, heated from 35°C to 150°C at 5°C / min, held at 150°C for 17 minutes, heated from 150°C to 220°C at 5°C / min, held at 220°C for 6 minutes. Carrier gas: Helium Injection mode: Split (split ratio 50) Control mode: Constant linear velocity (25.0 cm / sec) Pressure: 26.1 KPa Total flow rate: 52.5 mL / min Purge flow rate: 3.0 mL / min Column flow rate: 0.97 mL / min

[0104] [MS conditions] Ionization method: EI (Electron Ionization) Ion source temperature: 250°C Interface temperature: 250°C m / z detection range: 10 to 300 Detection time: 70 minutes Quantitative determination of the water concentration by the Karl Fischer method was performed using an automatic water content analyzer (product name: AQV-2200, manufactured by Hiranuma Sangyo Co., Ltd.).

[0105] Example 1 Using methyl acrylate as component A, 0.0186 g of component A was added to 10.0701 g of reagent methyl methacrylate (water concentration 240 ppm) to prepare a methyl methacrylate solution (solution A-1). The concentration of component A in the solution A-1 is shown in Table 1. Using 2,4-dimethyl-6-t-butylphenol as component B, 0.0228 g of component B was added to 10.0026 g of reagent methyl methacrylate (water concentration 240 ppm) to prepare a methyl methacrylate solution (solution B-1). The concentration of component B in the solution B-1 is shown in Table 1. Next, 0.1072 g of solution A-1 and 0.1062 g of solution B-1 were added to 20.0348 g of reagent methyl methacrylate (water concentration 240 ppm) to prepare a methyl methacrylate-containing composition. The concentrations of each component in the methyl methacrylate-containing composition are shown in Table 2. The concentration of component A in the methyl methacrylate-containing composition is referred to as MA (μmol / L). The resulting methyl methacrylate-containing composition was stored at 25°C for 14 days. Table 2 shows the amounts of methyl methacrylate dimer and methyl pyruvate produced in the methyl methacrylate-containing composition after storage.

[0106] Examples 2 to 9 A-1 solution was prepared in the same manner as in Example 1, except that the compound shown in Table 1 was used as component A and the amounts of methyl methacrylate and component A in the reagent were changed as shown in Table 1. A B-1 solution was prepared in the same manner as in Example 1. Next, a methyl methacrylate-containing composition was prepared in the same manner as in Example 1, except that the amounts of methyl methacrylate, A-1 solution, and B-1 solution in the reagent were changed as shown in Table 2. The concentrations of each component in the methyl methacrylate-containing composition are shown in Table 2. The obtained methyl methacrylate-containing composition was stored in the same manner as in Example 1. The amounts of methyl methacrylate dimer and methyl pyruvate produced in the methyl methacrylate-containing composition after storage are shown in Table 2.

[0107] Examples 10 to 15 A-1 solution was prepared in the same manner as in Example 1, except that the compound shown in Table 1 was used as component A and the amounts of methyl methacrylate and component A in the reagent were changed as shown in Table 1. A-1 solution was prepared in the same manner as in Example 1, except that the amounts of methyl methacrylate and component B in the reagent were changed as shown in Table 1. Next, a methyl methacrylate-containing composition was prepared in the same manner as in Example 1, except that the amounts of methyl methacrylate, A-1 solution, and B-1 solution in the reagent were changed as shown in Table 2. The concentrations of each component in the methyl methacrylate-containing composition are shown in Table 2. The obtained methyl methacrylate-containing composition was stored in the same manner as in Example 1. The amounts of methyl methacrylate dimer and methyl pyruvate produced in the methyl methacrylate-containing composition after storage are shown in Table 2.

[0108] Examples 16 to 22 An A-1 solution was prepared in the same manner as in Example 1. A B-1 solution was prepared in the same manner as in Example 1, except that the compound shown in Table 1 was used as component B, and the amounts of methyl methacrylate and component B in the reagent were changed as shown in Table 1. Next, a methyl methacrylate-containing composition was prepared in the same manner as in Example 1, except that the amounts of methyl methacrylate in the reagent, A-1 solution, and B-1 solution were changed as shown in Table 2. The concentrations of each component in the methyl methacrylate-containing composition are shown in Table 2. The obtained methyl methacrylate-containing composition was stored in the same manner as in Example 1. The amounts of methyl methacrylate dimer and methyl pyruvate produced in the methyl methacrylate-containing composition after storage are shown in Table 2.

[0109] Example 23 Solutions A-1 and B-1 were prepared in the same manner as in Example 1. Next, a methyl methacrylate-containing composition was prepared in the same manner as in Example 1, except that the amounts of methyl methacrylate, Solution A-1, and Solution B-1 in the reagents were changed as shown in Table 2. The concentrations of each component in the methyl methacrylate-containing composition are shown in Table 2. The obtained methyl methacrylate-containing composition was stored in the same manner as in Example 1. The amounts of methyl methacrylate dimer and methyl pyruvate produced in the methyl methacrylate-containing composition after storage are shown in Table 2.

[0110] Example 24 A B-1 solution was prepared in the same manner as in Example 1. Next, using methyl acrylate as component A, 0.0205 g of component A and 0.1086 g of B-1 solution were added to 20.0166 g of reagent methyl methacrylate (water concentration 240 ppm) to prepare a methyl methacrylate-containing composition. The concentrations of each component in the methyl methacrylate-containing composition are shown in Table 2. The obtained methyl methacrylate-containing composition was stored in the same manner as in Example 1. The amounts of methyl methacrylate dimer and methyl pyruvate produced in the methyl methacrylate-containing composition after storage are shown in Table 2.

[0111] Example 25 A B-1 solution was prepared in the same manner as in Example 1, except that the amounts of methyl methacrylate and component B in the reagent were changed as shown in Table 1. Next, a methyl methacrylate-containing composition was prepared in the same manner as in Example 24, except that the amounts of methyl methacrylate, component A, and B-1 solution in the reagent were changed as shown in Table 2. The concentrations of each component in the methyl methacrylate-containing composition are shown in Table 2. The obtained methyl methacrylate-containing composition was stored in the same manner as in Example 1. The amounts of methyl methacrylate dimer and methyl pyruvate produced in the methyl methacrylate-containing composition after storage are shown in Table 2.

[0112] Example 26 Solutions A-1 and B-1 were prepared in the same manner as in Example 1. Next, a methyl methacrylate-containing composition was prepared in the same manner as in Example 1, except that the amounts of methyl methacrylate, Solution A-1, and Solution B-1 in the reagents were changed as shown in Table 2. The concentrations of each component in the methyl methacrylate-containing composition are shown in Table 2. The obtained methyl methacrylate-containing composition was stored in the same manner as in Example 1. The amounts of methyl methacrylate dimer and methyl pyruvate produced in the methyl methacrylate-containing composition after storage are shown in Table 2.

[0113] Examples 27-28 An A-1 solution was prepared in the same manner as in Example 1. A B-1 solution was prepared in the same manner as in Example 1, except that the amounts of methyl methacrylate and component B in the reagent were changed as shown in Table 1. Next, a methyl methacrylate-containing composition was prepared in the same manner as in Example 1, except that the amounts of methyl methacrylate, A-1 solution, and B-1 solution in the reagent were changed as shown in Table 2. The concentrations of each component in the methyl methacrylate-containing composition are shown in Table 2. The obtained methyl methacrylate-containing composition was stored in the same manner as in Example 1. The amounts of methyl methacrylate dimer and methyl pyruvate produced in the methyl methacrylate-containing composition after storage are shown in Table 2.

[0114] Example 29 An A-1 solution was prepared in the same manner as in Example 1. Next, 0.1048 g of the A-1 solution was added to 20.0196 g of methyl methacrylate (water concentration 240 ppm) as a reagent to prepare a methyl methacrylate-containing composition. The concentrations of each component in the methyl methacrylate-containing composition are shown in Table 2. The obtained methyl methacrylate-containing composition was stored in the same manner as in Example 1. Table 2 shows the amounts of methyl methacrylate dimer and methyl pyruvate produced in the methyl methacrylate-containing composition after storage.

[0115] Comparative Example 1 A B-1 solution was prepared in the same manner as in Example 1. Next, 0.2213 g of B-1 solution was added to 40.0273 g of methyl methacrylate (water concentration 240 ppm) as a reagent to prepare a methyl methacrylate-containing composition. The concentrations of each component in the methyl methacrylate-containing composition are shown in Table 2. The obtained methyl methacrylate-containing composition was stored in the same manner as in Example 1. The amounts of methyl methacrylate dimer and methyl pyruvate produced in the methyl methacrylate-containing composition after storage are shown in Table 2.

[0116] (Comparative Example 2) 40.0000 g of methyl methacrylate (water concentration 240 ppm) as a reagent was used as a methyl methacrylate-containing composition and stored in the same manner as in Example 1. Table 2 shows the amounts of methyl methacrylate dimer and methyl pyruvate produced in the methyl methacrylate-containing composition after storage.

[0117] Comparative Example 3 A B-1 solution was prepared in the same manner as in Example 1. Using diacetyl as component C, 0.0205 g of component C was added to 9.9913 g of reagent methyl methacrylate (water concentration 240 ppm) to prepare a methyl methacrylate solution (C-1 solution). The concentration of component C in the C-1 solution is shown in Table 1. Next, 0.2151 g of B-1 solution and 0.2069 g of C-1 solution were added to 40.0218 g of reagent methyl methacrylate (water concentration 240 ppm) to prepare a methyl methacrylate-containing composition. The concentrations of each component in the methyl methacrylate-containing composition are shown in Table 2. The obtained methyl methacrylate-containing composition was stored in the same manner as in Example 1. Table 2 shows the amounts of methyl methacrylate dimer and methyl pyruvate produced in the methyl methacrylate-containing composition after storage.

[0118] Comparative Example 4 A-1 solution was prepared in the same manner as in Example 1, except that a compound shown in Table 1 was used as component A and the amounts of methyl methacrylate and component A in the reagent were changed as shown in Table 1. Next, a methyl methacrylate-containing composition was prepared in the same manner as in Example 29, except that the amounts of methyl methacrylate and A-1 solution in the reagent were changed as shown in Table 2. The concentrations of each component in the methyl methacrylate-containing composition are shown in Table 2. The obtained methyl methacrylate-containing composition was stored in the same manner as in Example 1. The amounts of methyl methacrylate dimer and methyl pyruvate produced in the methyl methacrylate-containing composition after storage are shown in Table 2.

[0119] Comparative Example 5 A B-1 solution was prepared in the same manner as in Example 1, except that the amounts of methyl methacrylate and component B in the reagent were changed as shown in Table 1. Next, a methyl methacrylate-containing composition was prepared in the same manner as in Example 24, except that the amounts of methyl methacrylate, component A, and B-1 solution in the reagent were changed as shown in Table 2. The concentrations of each component in the methyl methacrylate-containing composition are shown in Table 2. The obtained methyl methacrylate-containing composition was stored in the same manner as in Example 1. The amounts of methyl methacrylate dimer and methyl pyruvate produced in the methyl methacrylate-containing composition after storage are shown in Table 2.

[0120] Comparative Example 6 A-1 solution was prepared in the same manner as in Example 1. A B-1 solution was prepared in the same manner as in Example 1, except that the amounts of methyl methacrylate and component B in the reagent were changed as shown in Table 1. Next, 0.1106 g of A-1 solution, 0.0993 g of B-1 solution, and 0.2937 g of pure water were added to 20.0064 g of methyl methacrylate in the reagent (water concentration 240 ppm) to prepare a methyl methacrylate-containing composition. The concentrations of each component in the methyl methacrylate-containing composition are shown in Table 2. The obtained methyl methacrylate-containing composition was stored in the same manner as in Example 1. The amounts of methyl methacrylate dimer and methyl pyruvate produced in the methyl methacrylate-containing composition after storage are shown in Table 2.

[0121]

[0122]

[0123] As shown in Tables 1 and 2, in Examples 1 to 28, in which the methyl methacrylate-containing compositions contain the specified components A and B, the production of both methyl methacrylate dimer and methyl pyruvate is suppressed in the methyl methacrylate compositions after storage, and it can be said that the quality stability during storage is high. Furthermore, in Example 29, which contains the specified concentrations of components corresponding to components A2 and A3, the production of both methyl methacrylate dimer and methyl pyruvate is suppressed in the methyl methacrylate compositions after storage, even though it does not contain component B, and it can be said that the quality stability during storage is high. Furthermore, by polymerizing the polymerizable composition containing the methyl methacrylate-containing composition obtained in this example, a methyl methacrylate polymer can be obtained.

[0124] According to the present invention, a methyl methacrylate-containing composition that can be used as a raw material for acrylic resins, etc., can be stably stored for a long period of time, which is industrially useful.

Claims

1. A methyl methacrylate-containing composition comprising methyl methacrylate, an α,β-unsaturated carbonyl compound (component A1) represented by the following formula (1), and a polymerization inhibitor (component B), wherein the concentration of methyl methacrylate is 99 to 99.99% by mass: (In the above formula (1), R １ , R ２ and R ３ R each independently represents a hydrogen atom, an alkyl group, an alkenyl group, an aryl group, a hydroxy group, an alkoxy group, an amino group, a monovalent group containing a carbonyl group, an alkylthio group, or an arylthio group. ４ represents a monovalent group including an alkyl group, an alkenyl group, an aryl group, a hydroxy group, an alkoxy group, an amino group, or a carbonyl group, an alkylthio group, or an arylthio group. １ and R ２ , R ２ and R ３ , R ３ and R ４ may be linked to each other to form a ring. １ = H, and R ２ = H, and R ３ =CH ３ and R ４ =OCH ３ (H represents a hydrogen atom, C represents a carbon atom, and O represents an oxygen atom), i.e., the case where the α,β-unsaturated carbonyl compound represented by formula (1) is methyl methacrylate.

2. The methyl methacrylate-containing composition according to claim 1, wherein when the concentration of component A1 is MA1 (μmol / L) and the concentration of component B is MB (μmol / L), MB / MA1 is 0.1 or more.

3. The methyl methacrylate-containing composition according to claim 1, wherein the concentration of component A1 is MA1 (μmol / L), and MA1 is 1 to 85,000 μmol / L.

4. The methyl methacrylate-containing composition according to claim 3, wherein the MA1 is 10 to 40,000 μmol / L.

5. The methyl methacrylate-containing composition according to claim 1, wherein the concentration of component B is MB (μmol / L), and MB is 1 to 7000 μmol / L.

6. The methyl methacrylate-containing composition according to claim 5, wherein the MB is 10 to 5000 μmol / L.

7. The methyl methacrylate-containing composition according to claim 1, wherein the molecular weight of component A1 is 1,000 or less.

8. The methyl methacrylate-containing composition according to claim 1, wherein component B is at least one polymerization inhibitor selected from the group consisting of phenolic compounds, quinone compounds, nitrobenzene compounds, N-oxyl compounds, amine compounds, phosphorus-containing compounds, sulfur-containing compounds, iron-containing compounds, copper-containing compounds, and manganese-containing compounds.

9. The methyl methacrylate-containing composition according to claim 1, wherein component B is at least one polymerization inhibitor selected from the group consisting of phenolic compounds, N-oxyl compounds, amine compounds, phosphorus-containing compounds, and sulfur-containing compounds.

10. The methyl methacrylate-containing composition according to claim 1, wherein component B is at least one polymerization inhibitor selected from the group consisting of hydroquinone, 4-methoxyphenol, 2,4-dimethyl-6-t-butylphenol, 2,6-di-t-butyl-4-methylphenol, 4-hydroxy-2,2,6,6-tetramethylpiperidine-N-oxyl, N,N-diphenylamine, N-nitrosodiphenylamine, triphenyl phosphite, and phenothiazine.

11. In the above formula (1), R １ , R ２ and R ３ are each independently a hydrogen atom, an alkyl group having 1 to 5 carbon atoms, an alkenyl group having 2 to 5 carbon atoms, an aryl group having 1 to 12 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, an amino group, a monovalent group containing a carbonyl group, or an alkylthio group having 1 to 5 carbon atoms; R ４ is an alkyl group having 1 to 5 carbon atoms, an alkenyl group having 2 to 5 carbon atoms, an aryl group having 1 to 12 carbon atoms, a hydroxy group, an alkoxy group having 1 to 6 carbon atoms, an amino group, a monovalent group containing a carbonyl group, or an alkylthio group having 1 to 5 carbon atoms.

12. In the formula (1), R １ , R ２ and R ３ are each independently a hydrogen atom or an alkyl group having 1 to 5 carbon atoms, and R ４ The methyl methacrylate-containing composition according to claim 1, wherein is an alkyl group having 1 to 5 carbon atoms or an alkoxy group having 1 to 5 carbon atoms.

13. In the formula (1), R １ , R ２ and R ３ are each independently a hydrogen atom, a methyl group, an ethyl group, an n-propyl group, or an isopropyl group, and R ４ The methyl methacrylate-containing composition according to claim 1, wherein is a methyl group, a methoxy group, an ethoxy group, an n-propoxy group, an isopropoxy group, an n-butoxy group, an isobutoxy group, or an isopentoxy group.

14. The methyl methacrylate-containing composition according to claim 1, wherein the concentration of methyl methacrylate is 99.8 to 99.99% by mass.

15. The methyl methacrylate-containing composition according to claim 1, which does not contain diacetyl or contains diacetyl at a concentration of 55 μmol / L or less.

16. A methyl methacrylate-containing composition comprising methyl methacrylate and an α,β-unsaturated carboxylic acid ester (component A2) represented by the following formula (2), wherein the concentration of methyl methacrylate is 99 to 99.99 mass%, and when the concentration of component A2 is MA2 (μmol / L), the methyl methacrylate-containing composition has MA2 of 1 to 40,000 μmol / L. (In the above formula (2), R ５ , R ６ and R ７ R each independently represents a hydrogen atom, an alkyl group, an alkenyl group, an aryl group, a hydroxy group, an alkoxy group, an amino group, a monovalent group containing a carbonyl group, an alkylthio group, or an arylthio group. ８ represents an alkyl group, an alkenyl group, or an aryl group. ５ and R ６ , R ６ and R ７ , R ７ and R ８ may be linked to each other to form a ring. ５ = H, and R ６ = H, and R ７ =CH ３ and R ８ =CH ３ (Except for the case where the α,β-unsaturated carbonyl compound represented by formula (2) is methyl methacrylate, in which H represents a hydrogen atom, C represents a carbon atom, and O represents an oxygen atom.) 17. The methyl methacrylate-containing composition according to claim 16, wherein the MA2 is 10 to 5000 μmol / L.

18. The methyl methacrylate-containing composition according to claim 16, wherein the MA2 is 10 to 500 μmol / L.

19. The methyl methacrylate-containing composition according to claim 16, wherein the molecular weight of component A2 is 1,000 or less.

20. In the above formula (2), R ５ , R ６ and R ７ are each independently a hydrogen atom, an alkyl group having 1 to 5 carbon atoms, an alkenyl group having 2 to 5 carbon atoms, an aryl group having 1 to 12 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, an amino group, a monovalent group containing a carbonyl group, or an alkylthio group having 1 to 5 carbon atoms; R ８ The methyl methacrylate-containing composition according to claim 16, wherein is an alkyl group having 1 to 5 carbon atoms, an alkenyl group having 2 to 5 carbon atoms, or an aryl group having 1 to 12 carbon atoms.

21. In the formula (2), R ５ , R ６ and R ７ are each independently a hydrogen atom or an alkyl group having 1 to 5 carbon atoms, and R ８ The methyl methacrylate-containing composition according to claim 16, wherein is an alkyl group having 1 to 5 carbon atoms.

22. In the formula (2), R ５ , R ６ and R ７ are each independently a hydrogen atom, a methyl group, an ethyl group, an n-propyl group, or an isopropyl group, and R ８ The methyl methacrylate-containing composition according to claim 16, wherein is a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, an isobutyl group, or an isopentyl group.

23. In the formula (2), R ５ , R ６ and R ７ are each independently a hydrogen atom or a methyl group, and R ８ The methyl methacrylate-containing composition of claim 16, wherein is a methyl group.

24. The methyl methacrylate-containing composition according to claim 16, wherein the concentration of methyl methacrylate is 99.8 to 99.99% by mass.

25. The methyl methacrylate-containing composition according to claim 16, which does not contain diacetyl or contains diacetyl at a concentration of 55 μmol / L or less.

26. A methyl methacrylate-containing composition comprising methyl methacrylate and at least one compound (component A3) selected from the group consisting of methyl acrylate, butyl acrylate, ethyl methacrylate, methyl crotonate, cis-methyl crotonate, isobutyl methacrylate, butyl methacrylate, propyl methacrylate, isopentyl methacrylate, methyl 2-methylene-3-butenoate, methyl 3,3-dimethylacrylate, methyl 2-ethylacrylate, methyl 2-pentenoate, methyl cinnamate, methyl 3-methoxyacrylate, dimethyl fumarate, methyl 1-cyclohexene-1-carboxylate, methacrylamide, acrylic acid, crotonic acid, cis-crotonic acid, 3,3-dimethylacrylic acid, 2-ethylacrylic acid, 2-methylene-3-butenoic acid, and trans-3-hexen-2-one, wherein the concentration of methyl methacrylate is 99 to 99.99% by mass, When the concentration of the component A3 is MA3 (μmol / L), the methyl methacrylate-containing composition has MA3 of 1 to 40,000 μmol / L.

27. The methyl methacrylate-containing composition according to claim 26, wherein the MA3 is 10 to 5000 μmol / L.

28. The methyl methacrylate-containing composition according to claim 26, wherein the MA3 is 10 to 500 μmol / L.

29. The methyl methacrylate-containing composition according to claim 26, wherein component A3 is at least one member selected from the group consisting of methyl acrylate, methyl crotonate, acrylic acid, and crotonic acid.

30. The methyl methacrylate-containing composition according to claim 26, wherein the concentration of methyl methacrylate is 99.8 to 99.99% by mass.

31. The methyl methacrylate-containing composition according to claim 26, which does not contain diacetyl or contains diacetyl at a concentration of 55 μmol / L or less.

32. A method for producing a methyl methacrylate polymer, comprising the step of polymerizing a polymerizable composition comprising the methyl methacrylate-containing composition of any one of claims 1 to 31.

33. The method for producing a methyl methacrylate polymer according to claim 32, wherein the polymerizable composition contains at least 0.01 parts by weight of a monomer copolymerizable with methyl methacrylate per 100 parts by weight of methyl methacrylate.