Method for producing methyl methacrylate-containing composition and methyl methacrylate polymer

Abstract

The purpose of the present invention is to provide a methyl-methacrylate-containing composition having high quality stability in storage. The aforementioned problem is solved by a methyl-methacrylate-containing composition containing methyl methacrylate, a nitrile compound represented by formula (1), and a polymerization inhibitor, wherein the concentration of methyl methacrylate is 99-99.99 mass%.

Description

Technical Field

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

Background Art

[0002] Methyl methacrylate (hereinafter also referred to as "MMA") is known to be an extremely useful substance used as a raw material for various applications and types of polymers. For example, polymethyl methacrylate, which is a homopolymer of methyl methacrylate, is used in billboard signs, lighting equipment, automotive parts, building-related materials, light guide plates for flat displays, light diffusing plates, etc., taking advantage of its excellent transparency and weather resistance. Furthermore, copolymers of methyl methacrylate and other monomers are used in paints, adhesives, resin modifiers, artificial marble, paper latex, etc. Various methods for industrially producing methyl methacrylate have been developed, and for example, the acetone cyanohydrin (ACH) method, the new acetone cyanohydrin (new ACH) method, the C4 direct oxidation method, the direct meth method, the ethylene method, the new ethylene method, etc. are known (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 produced methyl methacrylate, and methyl methacrylate of a quality suitable for the intended use is obtained.

[0003] Because methyl methacrylate is easily polymerized, it is known that polymerization inhibitors are added to maintain the quality of methyl methacrylate during its production and storage (Non-Patent Document 2). For example, Patent Document 1 states that hydroquinone methyl ether (MEHQ) is particularly preferred among various polymerization inhibitors. Patent Document 2 states that N,N'-dialkyl-p-phenylenediamine and N-oxyl are preferred among various polymerization inhibitors. Patent Document 3 describes distilling methyl methacrylate in the presence of a phenolic polymerization inhibitor. Patent Document 4 describes using a diphenylamine derivative as a polymerization inhibitor. Patent Document 5 describes using a benzenetriamine derivative as a polymerization inhibitor. [Prior art documents] [Patent Documents]

[0004] [Patent Document 1] Japanese Patent Publication No. 2004-155757 [Patent Document 2] Special Publication No. 2005-502695 [Patent Document 3] Special Publication No. 10-504553 [Patent Document 4] Special Publication No. 2002-533309 [Patent Document 5] Special Publication No. 2002-513034 [Non-patent literature]

[0005] [Non-Patent Document 1] Kuroda, Toru, "Development of a catalyst for the production of methyl methacrylate," Catalysis, The Catalysis Society of Japan, 2003, Vol. 45, No. 5, pp. 366-371. [Non-Patent Document 2] Takayuki Otsu, "On the Function of Polymerization Inhibitors," Organic Synthesis Chemistry, The Society of Organic Synthesis, 1975, Vol. 33, No. 8, pp. 634-640. [Overview of the project] [Problems that the invention aims to solve]

[0006] However, even when the polymerization inhibitor was added, methyl methacrylate sometimes deteriorated in quality during storage. Therefore, the object of the present invention is to provide a methyl methacrylate-containing composition with high quality stability during storage. [Means for solving the problem]

[0007] The inventors diligently conducted research to achieve the above objectives. As a result, they found that when methyl methacrylate deteriorates in quality during storage, the methyl methacrylate concentration decreases, and methyl methacrylate dimers and methyl pyruvate are formed. The presence of methyl methacrylate dimers in methyl methacrylate can alter 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. The inventors then discovered that by including a nitrile compound with a specific structural formula in the methyl methacrylate-containing composition, the quality stability during storage is improved, and the formation of methyl methacrylate dimers and methyl pyruvate is suppressed, thus completing the present invention.

[0008] In other words, the present invention is as follows [1] to

[16] . [1]: A methyl methacrylate-containing composition comprising methyl methacrylate, a nitrile compound represented by the following formula (1), and a polymerization inhibitor (component B), A methyl methacrylate-containing composition having a methyl methacrylate concentration of 99 to 99.99% by mass. [ka] (In formula (1) above, R represents 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, and these groups may further have substituents.) [2]: The methyl methacrylate-containing composition according to [1], wherein when the concentration of component A is MA (μmol / L) and the concentration of component B is MB (μmol / L), MB / MA is 0.003 or more. [3]: The methyl methacrylate-containing composition according to [1] or [2], wherein the concentration of component A is MA (μmol / L), and MA is 1 to 20,000 μmol / L. [4]: The methyl methacrylate-containing composition according to [3], wherein the MA is 10 to 15000 μmol / L. [5]: A methyl methacrylate-containing composition according to any one of [1] to [4], wherein the concentration of component B is MB (μmol / L), and MB is 1 to 5000 μmol / L. [6]: The methyl methacrylate-containing composition according to [5], wherein the MB is 10 to 2500 μmol / L. [7]: A methyl methacrylate-containing composition according to any one of [1] to [6], wherein the molecular weight of component A is 1000 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 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 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] : A 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] : A methyl methacrylate-containing composition according to any one of [1] to

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

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

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

[13] : A methyl methacrylate-containing composition according to any one of [1] to

[12] , wherein R in formula (1) is an alkyl group having 1 to 3 carbon atoms, an alkenyl group having 2 to 3 carbon atoms, or an aryl group having 6 to 8 carbon atoms.

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

[13] , wherein R in formula (1) is a methyl group, an ethyl group, a vinyl group, an isopropenyl group, or a phenyl group.

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

[14] .

[16] : A method for producing a methyl methacrylate polymer according to

[15] , wherein the polymerizable composition comprises a monomer copolymerizable with methyl methacrylate. [Effects of the Invention]

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

[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 represented by "~" means a range including the numerical values described before and after "~" as the lower limit value and the upper limit value, and "A~B" means A or more and B or less.

[0011] [Methyl methacrylate-containing composition] [[ID=[8]]The methyl methacrylate-containing composition according to the present invention is a methyl methacrylate-containing composition containing methyl methacrylate, a nitrile compound (component A) represented by the following formula (1), and a polymerization inhibitor (component B), and the concentration of methyl methacrylate is 99 to 99.99% by mass. [Chemical formula]

[0012] <S In the above formula (1), R represents 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, and these groups may further have substituents. In addition, the methyl methacrylate-containing composition may 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 described in detail below.

[0013] (Component A) The methyl methacrylate-containing composition according to the present invention contains the nitrile compound (component A) represented by the above formula (1). By containing component A in the methyl methacrylate-containing composition, the formation of methyl methacrylate dimer and methyl pyruvate during storage of the methyl methacrylate-containing composition can be suppressed. The reason is presumed as follows.

[0014] Component B, described later, suppresses the dimerization reaction of methyl methacrylate by the radical mechanism by trapping radicals generated in methyl methacrylate. However, the dimerization reaction of methyl methacrylate also proceeds by a cationic mechanism in the presence of an acid catalyst. Component A, a nitrile compound, is weakly basic, and is thought to be able to trap trace amounts of acidic substances present in the methyl methacrylate composition, thereby inhibiting its function as an acid catalyst and suppressing the dimerization reaction of methyl methacrylate. Thus, since components A and B suppress the dimerization reaction of methyl methacrylate by different mechanisms, it is thought that the coexistence of both can efficiently suppress the formation of methyl methacrylate dimers. Furthermore, while methyl methacrylate undergoes hydrolysis under basic conditions, nitrile compounds are weakly basic and do not possess strong basicity sufficient to cause hydrolysis of methyl methacrylate. Therefore, component A is effective as a basic substance that traps trace amounts of acidic substances.

[0015] On the other hand, methyl pyruvate is produced when methyl methacrylate is oxidized by hydroxyl radicals and oxygen molecules. Component B can trap hydroxyl radicals, and component A can trap the radical intermediate produced by the reaction of hydroxyl radicals and methyl methacrylate, and convert the intermediate back to methyl methacrylate. Therefore, it is thought that the coexistence of components A and B can efficiently suppress the production of methyl pyruvate.

[0016] The molecular weight of component A is preferably 1000 or less. By having a molecular weight of 1000 or less, the number of cyano groups per unit mass in component A can be increased, so that the effects of the present invention can be obtained with a small mass. The molecular weight of component A is more preferably 800 or less, even more preferably 600 or less, and particularly preferably 400 or less.

[0017] In formula (1), R represents 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, and these groups may further have substituents.

[0018] When R satisfies the above conditions, the weak basicity of component A and its reactivity with acidic substances and radicals are maintained, thus enabling the effects of the present invention to be obtained. Furthermore, because it is a highly stable group, it can prevent component A from changing into other compounds during storage. R is preferably an alkyl group having 1 to 3 carbon atoms, an alkenyl group having 2 to 3 carbon atoms, or an aryl group having 6 to 8 carbon atoms. More preferably, R is a methyl group, an ethyl group, a vinyl group, an isopropenyl group, or a phenyl group.

[0019] Alkyl groups are linear (linear or branched) alkyl groups or cyclic alkyl groups. Examples of linear alkyl groups include methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, isobutyl group, s-butyl group, t-butyl group, n-pentyl group, and isopentyl group. Among these, methyl group, ethyl group, n-propyl group, and isopropyl group are preferred, with methyl group or ethyl group being more preferred. Examples of cyclic alkyl groups include cyclopropyl group, cyclobutyl group, and cyclopentyl group.

[0020] The alkenyl group is either a linear (linear or branched) alkenyl group or a cyclic alkenyl group. Examples of linear alkenyl groups include vinyl, 1-propenyl, isopropenyl, 2-butenyl, 1,3-butadienyl, and 2-pentenyl groups. Among these, vinyl, 1-propenyl, and isopropenyl groups are preferred, with vinyl or isopropenyl groups being more preferred. Examples of cyclic alkenyl groups include cyclopropenyl, cyclobutenyl, and cyclopentenyl groups.

[0021] The aryl group includes heteroaryl groups containing oxygen, nitrogen, sulfur, etc. Examples of aryl groups include phenyl group, mesityl group, naphthyl group, 2-methylphenyl group, 3-methylphenyl group, 4-methylphenyl group, 2,3-dimethylphenyl group, 2,4-dimethylphenyl group, 2,5-dimethylphenyl group, 2,6-dimethylphenyl group, 2-ethylphenyl group, isoxazolyl group, isothiazolyl group, imidazolyl group, oxazolyl group, thiazolyl group, thiadiazolyl group, thienyl group, triazolyl group, tetrazolyl group, pyridyl group, pyrazinyl group, pyrimidinyl group, pyridadinyl group, pyrazolyl group, pyrrolyl group, furyl group, fluzanyl group, isoquinolyl group, isoindolyl group, indolyl group, quinolyl group, pyridothiazolyl group, benzimidazolyl group, benzoxazolyl group, benzothiazolyl group, benzotriazolyl group, benzofuranyl group, imidazopyridinyl group, triazopyridinyl group, and prinyl group.

[0022] When R is a substituted alkyl group, alkenyl group, or aryl group, examples of substituents include monovalent groups including alkyl groups, alkenyl groups, aryl groups, hydroxyl groups, alkoxy groups, amino groups, and carbonyl groups, as well as alkylthio groups and arylthio groups. Among these, monovalent groups including hydroxyl groups, alkoxy groups, amino groups, and carbonyl groups, and alkylthio groups are preferred, and hydroxyl groups, methoxy groups, amino groups, acetyl groups, and methylthio groups are more preferred. The molecular weight of the substituent is preferably 200 or less, more preferably 100 or less, and even more preferably 50 or less. The number of carbon atoms in R is the number of carbon atoms in the alkyl group, alkenyl group, or aryl group, including the carbon atoms of these substituents. For example, in 4-(methylthio)benzonitrile, R is considered to be a 4-(methylthio)phenyl group with an aryl group having 7 carbon atoms.

[0023] The alkyl group as a substituent is the same as the alkyl group described above, insofar as 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. The alkyl group as a substituent has 1 to 11 carbon atoms, preferably 1 to 6, and more preferably 1 to 3.

[0024] The alkenyl group as a substituent is the same as the alkenyl group described above, insofar as 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. The number of carbon atoms in the alkenyl group as a substituent is 2 to 11, preferably 2 to 6, and more preferably 2 to 3.

[0025] The aryl group as a substituent is the same as the aryl group described above, insofar as 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. The aryl group as a substituent has 1 to 11 carbon atoms, preferably 3 to 9, and more preferably 5 to 7.

[0026] The alkoxy group used as a substituent is an alkoxy group having 1 to 11 carbon atoms, preferably an alkoxy group having 1 to 6 carbon atoms, and more preferably an alkoxy group having 1 to 3 carbon atoms. However, 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. Examples of alkoxy groups include methoxy, ethoxy, n-propoxy, isopropoxy, n-butoxy, isobutoxy, s-butoxy, t-butoxy, n-pentoxy, isopentoxy, and phenoxy groups.

[0027] The amino group as a substituent includes an amino group (-NH2) with no substituent on the nitrogen atom, and an amino group in which some or all of the hydrogen atoms bonded to the nitrogen atom are substituted with carbon atoms. The number of carbon atoms in the carbon-substituted amino group is 1 to 11, preferably 1 to 6, and more preferably 1 to 3. However, 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. Examples of amino groups include methylamino group, ethylamino group, propylamino group, butylamino group, dimethylamino group, diethylamino group, anilino group, toluidino group, anisidino group, and N-methyl-N-phenylamino group.

[0028] Examples of monovalent groups containing a carbonyl group that can be used as substituents include formyl group, acyl group, carboxyl group, amide group, alkoxycarbonyl group, thiocarboxyl group, thioester group, and the like.

[0029] An acyl group is a substituent formed by linking a carbonyl group with an alkyl group, alkenyl group, or aryl group. The sum of the carbon atoms derived from the carbonyl group (1) and the carbon atoms derived from the alkyl group, alkenyl group, or aryl group is 2 to 11, preferably 2 to 7, and more preferably 2 to 4. However, 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. Examples of acyl groups include acetyl group, propionyl group, butylcarbonyl group, vinylcarbonyl group, and benzoyl group.

[0030] The amide group includes an amide group without substituents on the nitrogen atom (-CONH2) and an amide group in which some or all of the hydrogen atoms bonded to the nitrogen atom are substituted with carbon atoms. The total number of carbon atoms in the amide group is 1 to 11, preferably 1 to 7, and more preferably 1 to 4, which is the sum of the carbon atoms derived from the carbonyl group (1) and the carbon atoms substituted on the nitrogen atom. However, R is an alkyl group with 1 to 5 carbon atoms, an alkenyl group with 2 to 5 carbon atoms, or an aryl group with 1 to 12 carbon atoms. Examples of amide groups include unsubstituted amide groups, N-methylamide groups, N-ethylamide groups, N-phenylamide groups, N,N-dimethylamide groups, and N-methyl-N-phenylamide groups.

[0031] An alkoxycarbonyl group is a substituent formed by linking a carbonyl group and an alkoxy group, and is also called an ester group. The total number of carbon atoms from the carbonyl group (1) and the alkoxy group is 2 to 11, preferably 2 to 7, and more preferably 2 to 4. However, R is an alkyl group with 1 to 5 carbon atoms, an alkenyl group with 2 to 5 carbon atoms, or an aryl group with 1 to 12 carbon atoms. Examples of alkoxycarbonyl groups include methoxycarbonyl, ethoxycarbonyl, butoxycarbonyl, and phenoxycarbonyl groups.

[0032] A thioester group is a substituent formed by linking a carbonyl group with an alkylthio group or an arylthio group. The total number of carbon atoms derived from the carbonyl group (1) and the alkylthio group or arylthio group is 2 to 11, preferably 2 to 7, and more preferably 2 to 4. However, R is an alkyl group with 1 to 5 carbon atoms, an alkenyl group with 2 to 5 carbon atoms, or an aryl group with 1 to 12 carbon atoms. Examples of thioester groups include methylthiocarbonyl group, ethylthiocarbonyl group, butylthiocarbonyl group, and phenylthiocarbonyl group.

[0033] Furthermore, the monovalent group containing a carbonyl group may be a substituent in which one or more hydrogen atoms of an alkyl group are substituted with a carbonyl group. Examples of such substituents include 2-acetoxyethyl group, 2-acetoethyl group, and 2-(acetoacetoxy)ethyl group.

[0034] The alkylthio group used as a substituent is an alkylthio group having 1 to 11 carbon atoms, preferably an alkylthio group having 1 to 6 carbon atoms, and more preferably an alkylthio group having 1 to 3 carbon atoms. However, 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. Examples of alkylthio groups include methylthio group, ethylthio group, propylthio group, and isopropylthio group.

[0035] The arylthio group used as a substituent is an arylthio group having 1 to 11 carbon atoms, preferably an arylthio group having 3 to 9 carbon atoms, and more preferably an arylthio group having 5 to 7 carbon atoms. However, 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. Examples of arylthio groups include phenylthio groups and tolylthio groups.

[0036] Among the compounds that satisfy the above conditions, from the viewpoint of quality stability during storage of the methyl methacrylate-containing composition, component A is preferably methacrylonitrile, acetonitrile, propionitrile, acrylonitrile, benzonitrile, cyclohexanecarbonile, 3-hydroxypropionitrile, 3-methoxypropionitrile, 2-hydroxypropionitrile, 2-aminopropionitrile, 4-cyanophenol, 4-aminobenzonitrile, 4'-cyanoacetophenone, or 4-(methylthio)benzonitrile, more preferably methacrylonitrile, acetonitrile, propionitrile, acrylonitrile, benzonitrile, 3-hydroxypropionitrile, 3-methoxypropionitrile, 4-aminobenzonitrile, 4'-cyanoacetophenone, or 4-(methylthio)benzonitrile, and even more preferably methacrylonitrile, acetonitrile, propionitrile, acrylonitrile, benzonitrile, 3-hydroxypropionitrile, or 4-(methylthio)benzonitrile.

[0037] Component A may be one type or two or more types.

[0038] (Component B) The methyl methacrylate-containing composition according to the present invention contains a polymerization inhibitor (component B). In this specification, a polymerization inhibitor means a compound that has the function of suppressing 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 by a radical polymerization mechanism can be suppressed during storage of methyl methacrylate. Furthermore, as described above, the coexistence of component A and component B can efficiently suppress the formation of methyl methacrylate dimers and the formation of methyl pyruvate by oxidation of methyl methacrylate.

[0039] Examples of polymerization inhibitors that are phenolic compounds include alkylphenols, hydroxyphenols, aminophenols, nitrophenols, nitrosophenols, alkoxyphenols, and tocopherols.

[0040] 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'-methylenebis(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.

[0041] 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.

[0042] Examples of aminophenols include o-aminophenol, m-aminophenol, p-aminophenol, 2-(N,N-dimethylamino)phenol, and 4-(ethylamino)phenol.

[0043] Examples of nitrophenols include o-nitrophenol, m-nitrophenol, p-nitrophenol, and 2,4-dinitrophenol. Examples of nitrosophenols include o-nitrosophenol, m-nitrosophenol, p-nitrosophenol, and α-nitroso-β-naphthol.

[0044] 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.

[0045] Examples of tocopherols include α-tocopherol and 2,3-dihydro-2,2-dimethyl-7-hydroxybenzofuran.

[0046] Examples of polymerization inhibitors that are quinone compounds 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.

[0047] Examples of polymerization inhibitors that are nitrobenzene compounds include nitrobenzene, o-dinitrobenzene, m-dinitrobenzene, p-dinitrobenzene, 2,4-dinitrotoluene, dinitrojulene, and 2,2-diphenyl-1-picrylhydrazyl.

[0048] Examples of polymerization inhibitors that are N-oxyl compounds 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 Examples include 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, etc.

[0049] Examples of polymerization inhibitors that are amine compounds 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 group consists of 1 to 4 carbon atoms independently of each other, 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 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-benzoylioxy-2,2,6,6-tetramethylpiperidine.

[0050] Examples of polymerization inhibitors containing phosphorus include triphenylphosphine, triphenyl phosphite, triethyl phosphite, tris(isodecyl) phosphite, tris(tridecyl) phosphite, phenyldiisooctyl phosphite, phenyldiisodecyl phosphite, phenyldi(tridecyl) phosphite, diphenylisooctyl phosphite, diphenylisodecyl phosphite, diphenyltridecyl phosphite, phosphonic acid [1,1-diphenyl-4,4'-diylbistetrakis-2,4-bis(1,1-dimethylethyl)phenyl] ester, triphenyl phosphite, tris(nonylphenyl) phosphite, 4,4'-isopropylidenediphenolalkyl phosphite, tris(2,4-di-tert-butylphenyl) phosphite, tris(biphenyl) phosphite, and distearyl phosphate. Examples include pentaerythritol diphosphite, di(2,4-di-tert-butylphenyl)pentaerythritol diphosphite, di(nonylphenyl)pentaerythritol diphosphite, phenylbisphenol 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, and 1,3-bis(diphenoxyphosphonyloxy)benzene.

[0051] Examples of polymerization inhibitors containing sulfur include diphenyl sulfide, phenothiazine, 3-oxofhenothiazine, 5-oxofhenothiazine, phenothiazine dimers, 1,4-dimercaptobenzene, 1,2-dimercaptobenzene, 2-mercaptophenol, 4-mercaptophenol, 2-(methylthio)phenol, 3,7-bis(dimethylamino)phenothiazinium chloride, and elemental sulfur.

[0052] Examples of polymerization inhibitors that contain iron include iron(III) chloride.

[0053] Examples of polymerization inhibitors containing copper 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.

[0054] Examples of manganese-containing polymerization inhibitors include manganese dialkyldithiocarbamate (the alkyl group is one of methyl, ethyl, propyl, or 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.

[0055] 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.

[0056] Component B may be one type or two or more types. Furthermore, if a methyl methacrylate-containing composition contains a compound that corresponds to both component A and component B, that compound shall be considered as component B. In other words, the methyl methacrylate-containing composition must contain a component A other than the compound in question. Furthermore, if two or more compounds that correspond to both component A and component B are contained, the compound with the highest molar concentration in the methyl methacrylate composition shall be considered as component B, and the other compounds shall be considered as component A.

[0057] (Concentrations of component A and component B) When the concentration of component A is MA (μmol / L) and the concentration of component B is MB (μmol / L), it is preferable that MB / MA be 0.003 or higher from the viewpoint of efficiency in suppressing the formation of methyl methacrylate dimer and methyl pyruvate. There is no particular upper limit to MB / MA, but it is usually 100 or less, and preferably 50 or less.

[0058] The MA is preferably 1 to 20,000 μmol / L. An MA of 1 μmol / L or higher provides sufficient suppression of methyl methacrylate dimer and methyl pyruvate formation. Furthermore, an MA of 20,000 μmol / L or less reduces the amount of impurities when a methyl methacrylate polymer is produced by polymerization of the methyl methacrylate-containing composition according to the present invention, preventing adverse effects on the properties of the polymer. The lower limit of MA is more preferably 10 μmol / L or higher, even more preferably 50 μmol / L or higher, and particularly preferably 60 μmol / L or higher. The upper limit of the concentration of component A is more preferably 15,000 μmol / L or lower, even more preferably 10,000 μmol / L or lower, particularly preferably 5,000 μmol / L or lower, and most preferably 1,000 μmol / L or lower.

[0059] The MB is preferably 1 to 5000 μmol / L. An MB of 1 μmol / L or higher is sufficient to suppress the formation of methyl methacrylate dimers and methyl pyruvate. Furthermore, an MB of 5000 μmol / L or lower reduces the amount of impurities when a methyl methacrylate polymer is produced by polymerization of the methyl methacrylate-containing composition according to the present invention, preventing adverse effects on the properties of the polymer. The lower limit of MB is more preferably 10 μmol / L or higher, and even more preferably 30 μmol / L or higher. The upper limit of the concentration of component B is more preferably 2500 μmol / L or lower, even more preferably 2000 μmol / L or lower, particularly preferably 1000 μmol / L or lower, and most preferably 600 μmol / L or lower.

[0060] (Concentration of methyl methacrylate) The concentration of methyl methacrylate in the methyl methacrylate-containing composition according to the present invention is 99 to 99.99% by mass. A concentration of 99% by mass or higher reduces the amount of impurities produced when a methyl methacrylate polymer is manufactured by polymerization of the methyl methacrylate-containing composition according to the present invention, thereby preventing adverse effects on the properties of the polymer. Furthermore, a concentration of 99.99% by mass or lower reduces the purification cost. The lower limit of the methyl methacrylate concentration is preferably 99.8% by mass or higher.

[0061] (Component C) The methyl methacrylate-containing composition according to the present invention may contain other compounds (component C) as long as the concentration of methyl methacrylate satisfies 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, but from the viewpoint of reducing the discoloration of the methyl methacrylate-containing composition, the concentration of diacetyl is preferably 55 μmol / L, more preferably 20 μmol / L or less, even more preferably 10 μmol / L or less, and particularly preferably 1 μmol / L.

[0062] (Analysis of methyl methacrylate-containing compositions) The presence of methyl methacrylate-containing compositions in components A, B, C, and water can be confirmed, for example, by GC-MS measurement. If the GC-MS chart of the methyl methacrylate-containing composition shows a peak at the same retention time as the standard of component A, and the m / z value detected in the mass spectrum of that peak matches the exact mass of component A, then the methyl methacrylate-containing composition can be determined to contain component A. If a standard of component A is unavailable, the peak can be determined to be component A 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 A recorded in a mass spectrum database. In other words, the methyl methacrylate-containing composition can be determined to contain component A. Examples of mass spectrum databases include NIST20, NIST17, NIST14, and NIST14s. Furthermore, if 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. Furthermore, the concentration of methyl methacrylate can be calculated, for example, by performing a GC-FID measurement of the methyl methacrylate-containing composition, quantifying it using the area percentage method, and correcting it using the moisture concentration quantified with a Karl Fischer moisture meter. The concentration of component A can be calculated, for example, by performing a GC measurement of the methyl methacrylate-containing composition and quantifying it using the internal standard method. If a standard sample of component A cannot be obtained and quantification cannot be performed by the internal standard method, the concentration of component A can be calculated using the following formula by performing a GC-FID measurement of any organic compound with a known concentration under the same conditions as the methyl methacrylate-containing composition.

number

[0063] [Method for producing a methyl methacrylate-containing composition] One method for producing the methyl methacrylate-containing composition according to the present invention is to add component A and component B to methyl methacrylate. The methyl methacrylate may be a commercially available product, or it may be methyl methacrylate produced by known methods 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. Components A and B may be commercially available products, or they may be synthesized by known methods. When using methyl methacrylate produced by known methods 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, component A or component B may be added as a raw material or during the manufacturing process to produce the methyl methacrylate-containing composition. Furthermore, if component A or component B is generated as a by-product in the methyl methacrylate manufacturing process, the methyl methacrylate-containing composition may be produced by leaving a portion of the generated component A or component B.

[0064] [Methods for evaluating storage stability and thermal stability] The methyl methacrylate-containing composition according to the present invention exhibits high quality stability during storage. Methods for evaluating the quality stability of the methyl methacrylate-containing composition during storage include, for example, actually storing the methyl methacrylate-containing composition for a long period and confirming the amount of methyl methacrylate dimer and methyl pyruvate produced. Alternatively, from the viewpoint of ease of operation, a method of heating the methyl methacrylate-containing composition for a short time and confirming the amount of methyl methacrylate dimer and methyl pyruvate produced may be used. When heating for a short 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 the methyl methacrylate-containing composition during storage is evaluated based on the amount of methyl methacrylate dimer and methyl pyruvate produced when the methyl methacrylate-containing composition is stored at 25°C for 14 days.

[0065] [Methacrylate Polymer Production Method] 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.

[0066] <Polymerizable composition> The polymerizable composition may optionally contain monomers copolymerizable with methyl methacrylate and other additives.

[0067] (A monomer copolymerizable with methyl methacrylate) Examples of monomers copolymerizable with methyl methacrylate include the following: Methacrylic acid esters such as ethyl methacrylate, isopropyl methacrylate, n-butyl methacrylate, iso-butyl methacrylate, tert-butyl methacrylate, 2-ethylhexyl methacrylate, phenyl methacrylate, or benzyl methacrylate; Acrylic acid esters such as methyl acrylate, ethyl acrylate, n-butyl acrylate, iso-butyl 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; 2-hydroxyethyl acrylate, 2-hydroxyethyl methacrylate, or 2-hydroxypropyl methacrylate, or other hydroxyl group-containing vinyl monomers; Vinyl esters such as vinyl acetate or vinyl benzoate; Vinyl chloride, vinylidene chloride, and their derivatives; 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; Alkane diol 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 their molecules, such as divinylbenzene; Unsaturated polyester prepolymer obtained from at least one polycarboxylic acid containing an ethylenically unsaturated polycarboxylic acid and at least one diol; Vinyl ester prepolymer obtained by modifying the ends of epoxy groups with acrylic;

[0068] 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. This makes it possible to obtain a methyl methacrylate polymer with an excellent balance of transparency, heat resistance, and moldability by polymerizing the polymerizable composition. The monomer copolymerizable with methyl methacrylate is more preferably an acrylic acid ester, and is particularly preferably at least one selected from the group consisting of methyl acrylate, ethyl acrylate, and n-butyl acrylate.

[0069] The monomer copolymerizable with methyl methacrylate may be one type or two or more types. Furthermore, if 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.

[0070] In the polymerizable composition, the content of monomers copolymerizable with methyl methacrylate is preferably 0 to 50 parts by mass per 100 parts by mass of methyl methacrylate. This makes it possible to obtain a highly transparent methyl methacrylate polymer. The upper limit of the content of monomers copolymerizable with methyl methacrylate is 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 monomers copolymerizable with methyl methacrylate is more preferably 0.01 parts by mass or more, even more preferably 0.1 parts by mass or more, and particularly preferably 1 part by mass or more, per 100 parts by mass of methyl methacrylate.

[0071] (Other additives) Other additives preferably include polymerization initiators. Additionally, chain transfer agents, mold release agents, lubricants, plasticizers, antioxidants, antistatic agents, light stabilizers, UV absorbers, flame retardants, flame retardant aids, polymerization inhibitors, fillers, pigments, dyes, silane coupling agents, leveling agents, defoamers, fluorescent agents, etc. The other additives may be one type or two or more types.

[0072] Examples of polymerization initiators 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(cyclohexanecarbonitride), 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-hexyl peroxy Organic peroxides such as -oxy-2-ethylhexanoate, t-amyl peroxy-2-ethylhexanoate, 1,1,3,3-tetramethylbutyl peroxyethylhexanoate, 1,1,2-trimethylpropyl peroxy-2-ethylhexanoate, 1,1,3,3-tetramethylbutyl peroxyisopropyl monocarbonate, 1,1,2-trimethylpropyl peroxyisopropyl monocarbonate, 1,1,3,3-tetramethylbutyl peroxyisononate, 1,1,2-trimethylpropyl peroxyisononate, di-t-butyl peroxide, di-t-hexyl peroxide, lauroyl peroxide, and dilauroyl peroxide; Persulfate compounds such as potassium persulfate; Redox polymerization initiators;

[0073] Among the above, from the viewpoint 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 polymerization initiator used is preferably 0.0001 to 1 part by mass per 100 parts by mass of methyl methacrylate and monomers copolymerizable with methyl methacrylate.

[0074] <Method for polymerizing polymerizable compositions> Polymerization methods include, for example, bulk polymerization, solution polymerization, emulsion polymerization, and suspension polymerization. Bulk polymerization is preferred from the viewpoint of environmental impact due to solvent use and the transparency of the resulting methyl methacrylate polymer.

[0075] The specific methods for bulk polymerization are not particularly limited, but it can be manufactured using known casting polymerization methods such as the cell casting method or the continuous casting method. Cast polymerization is a method for obtaining a methyl methacrylate polymer by injecting a polymerizable composition into a mold consisting of two inorganic glass plates or metal plates (e.g., SUS plates) that are placed opposite each other at a predetermined distance and sealed around the periphery with a gasket such as a flexible resin tube, and allowing polymerization to proceed. The mold for casting polymerization is not particularly limited, and known molds can be used. Examples of molds for cell casting include those in which two plate-like bodies such as inorganic glass plates, chrome-plated metal plates, and stainless steel plates are placed facing each other at a predetermined distance, and gaskets are placed on the edges thereof to form a sealed space with the plate-like bodies and gaskets. Examples of molds for continuous casting include those in which a sealed space is formed by the opposing surfaces of a pair of endless belts traveling in the same direction at the same speed, and gaskets traveling at the same speed as the endless belts on both sides of the endless belts.

[0076] The spacing of the voids in the mold is adjusted as needed to obtain a resin plate of the desired thickness, but it is generally between 1 and 30 mm. The polymerization temperature is preferably 125 to 210°C. This allows for obtaining 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. [Examples]

[0077] 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. Unless otherwise specified, "%" and "ppm" in the examples and comparative examples mean "weight percent" and "weight ppm". The water content of the methyl methacrylate reagent was calculated using the Karl Fischer method. The composition of the methyl methacrylate-containing composition before storage was calculated from the amount of each raw material added. After storage, the methyl methacrylate dimer and methyl pyruvate in the methyl methacrylate-containing composition were quantified using GC-MS with an absolute calibration curve. The GC-MS measurement conditions are shown below. Equipment: GC-MS measurement equipment (product name: QP-2010SE, manufactured by Shimadzu Corporation)

[0078] [GC conditions] Column (Product name: DB-WAX, manufactured by Agilent Technologies) Length: 60m, Inner diameter: 0.32mm, Film thickness: 1.00μm Injection volume: 1.0μL Evaporation chamber temperature: 210℃ Column oven temperature: Hold at 35°C for 10 minutes, increase temperature from 35°C to 150°C at a rate of 5°C / min, hold at 150°C for 17 minutes, increase temperature from 150°C to 220°C at a rate of 5°C / min, hold 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: 52.5mL / min Purge flow rate: 3.0 mL / min Column flow rate: 0.97 mL / min

[0079] [MS conditions] Ionization method: EI (Electron Ionization) Ion source temperature: 250℃ Interface temperature: 250℃ m / z detection range: 10-300 Detection time: 70 minutes The moisture concentration was determined using the Karl Fischer method with an automated moisture analyzer (product name: AQV-2200, manufactured by Hiranuma Sangyo Co., Ltd.).

[0080] (Example 1) Methacrylonitrile was used as component A, and 0.0229 g of component A was added to 10.0275 g of reagent methyl methacrylate (water concentration 240 ppm) to prepare a methyl methacrylate solution (Solution A-1). The concentration of component A in 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 methyl methacrylate solution (Solution B-1). The concentration of component B in Solution B-1 is shown in Table 1. Next, 0.10016 g of Solution A-1 and 0.1027 g of Solution B-1 were added to 20.0053 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 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.

[0081] (Examples 2-5) Solution A-1 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. Solution B-1 was prepared using the same method 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 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. Table 2 shows the amounts of methyl methacrylate dimer and methyl pyruvate produced in the methyl methacrylate-containing composition after storage.

[0082] (Examples 6-10) Solution A-1 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. Solution B-1 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, solution A-1, and solution B-1 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. Table 2 shows the amounts of methyl methacrylate dimer and methyl pyruvate produced in the methyl methacrylate-containing composition after storage.

[0083] (Examples 11-17) Solution A-1 was prepared using the same method as in Example 1. Solution B-1 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, solution A-1, and solution B-1 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. Table 2 shows the amounts of methyl methacrylate dimer and methyl pyruvate produced in the methyl methacrylate-containing composition after storage.

[0084] (Example 18) Solution A-1 and Solution 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 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. Table 2 shows the amounts of methyl methacrylate dimer and methyl pyruvate produced in the methyl methacrylate-containing composition after storage.

[0085] (Example 19) Solution A-1 was prepared using the same method as in Example 1. Solution B-1 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, solution A-1, and solution B-1 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. Table 2 shows the amounts of methyl methacrylate dimer and methyl pyruvate produced in the methyl methacrylate-containing composition after storage.

[0086] (Example 20) Solution B-1 was prepared using the same method as in Example 1. Next, using methacrylonitrile as component A, 0.0229 g of component A and 0.1090 g of solution B-1 were added to 20.0100 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.

[0087] (Examples 21-22) Solution A-1 was prepared using the same method as in Example 1. Solution B-1 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, solution A-1, and solution B-1 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. Table 2 shows the amounts of methyl methacrylate dimer and methyl pyruvate produced in the methyl methacrylate-containing composition after storage.

[0088] (Comparative Example 1) Solution B-1 was prepared using the same method as in Example 1. Next, 0.2213 g of Solution B-1 was added to 40.0273 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.

[0089] (Comparative Example 2) 40.0000 g of reagent methyl methacrylate (water concentration 240 ppm) was prepared 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.

[0090] (Comparative Example 3) Solution B-1 was prepared using the same method as in Example 1. Diacetyl was used as component C, and 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 (Solution C-1). The concentration of component C in Solution C-1 is shown in Table 1. Next, 0.2151 g of solution B-1 and 0.2069 g of solution C-1 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.

[0091] (Comparative Example 4) Solution A-1 was prepared using the same method as in Example 1. Next, 0.2054 g of Solution A-1 was added to 40.0249 g of the 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.

[0092] (Comparative Example 5) Solution A-1 was prepared using the same method as in Example 1. Solution B-1 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, 20.0192 g of reagent methyl methacrylate (water concentration 240 ppm) was mixed with 0.1010 g of solution A-1, 0.1051 g of solution B-1, and 0.3003 g of pure water 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.

[0093] [Table 1]

[0094] [Table 2] [Industrial applicability]

[0095] According to the present invention, a methyl methacrylate-containing composition that can be used as a raw material for acrylic resins, etc., can be stored stably for a long period of time, making it industrially useful.

Claims

1. A methyl methacrylate-containing composition comprising methyl methacrylate, a nitrile compound represented by the following formula (1) (component A), and a polymerization inhibitor (component B), A methyl methacrylate-containing composition having a methyl methacrylate concentration of 99 to 99.99% by mass. 【Chemistry 1】 (In formula (1) above, R represents 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 groups may further have substituents selected from alkyl groups, alkenyl groups, aryl groups, hydroxyl groups, alkoxy groups, amino groups, monovalent groups including carbonyl groups, alkylthio groups, and arylthio groups.)

2. The methyl methacrylate-containing composition according to claim 1, wherein when the concentration of component A is MA (μmol / L) and the concentration of component B is MB (μmol / L), MB / MA is 0.003 or more.

3. The methyl methacrylate-containing composition according to claim 1, wherein the concentration of component A is MA (μmol / L), and MA is 1 to 20,000 μmol / L.

4. The methyl methacrylate-containing composition according to claim 3, wherein the MA is 10 to 15,000 μmol / L.

5. When the concentration of component B is MB (μmol / L), MB is 1 to 5000 μmol / L A methyl methacrylate-containing composition according to claim 1, wherein L.

6. The methyl methacrylate-containing composition according to claim 5, wherein the MB is 10 to 2500 μmol / L.

7. The methyl methacrylate-containing composition according to claim 1, wherein the molecular weight of component A is 1000 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. The methyl methacrylate-containing composition according to claim 1, wherein the concentration of methyl methacrylate is 99.8 to 99.99% by mass.

12. The methyl methacrylate-containing composition according to claim 1, wherein it does not contain diacetyl, or the concentration of diacetyl contained is 55 μmol / L or less.

13. The methyl methacrylate-containing composition according to claim 1, wherein in formula (1), 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.

14. The methyl methacrylate-containing composition according to claim 1, wherein R is an alkyl group having 1 to 3 carbon atoms, an alkenyl group having 2 to 3 carbon atoms, or an aryl group having 6 to 8 carbon atoms.

15. The methyl methacrylate-containing composition according to claim 1, wherein R in formula (1) is a methyl group, an ethyl group, a vinyl group, an isopropenyl group, or a phenyl group.

16. A method for producing a methyl methacrylate polymer, comprising the step of polymerizing a polymerizable composition containing the methyl methacrylate-containing composition described in any one of claims 1 to 15.

17. The method for producing a methyl methacrylate polymer according to claim 16, wherein the polymerizable composition comprises a monomer copolymerizable with methyl methacrylate.

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