Composition, polymer, cured product, molded product, and method for producing polymethyl methacrylate

Abstract

The present invention provides a composition which can give a molded article having excellent heat resistance, a polymer, a cured product and a molded article which can be obtained using the composition, and a method for producing polymethyl methacrylate which uses the composition. [Solution] A composition containing methyl methacrylate, methyl pivalate and water, wherein the concentration of methyl pivalate is greater than 0 ppm by mass and not greater than 10,000 ppm by mass of the total composition, and the concentration of water is greater than 0 ppm by mass and not greater than 10,000 ppm by mass of the total composition.

Description

[Technical field]

[0001] The present disclosure relates to a composition, a polymer, a cured product, a molded article, and a method for producing polymethyl methacrylate. [Background technology]

[0002] Poly(methyl(meth)acrylate) obtained by polymerizing methyl(meth)acrylate is used in various fields as a resin material with excellent transparency and weather resistance. In recent years, due to the rise in resource prices and the growing awareness of environmental issues, products (molded articles) containing poly(methyl(meth)acrylate) used for various applications as described above are being collected and recycled.

[0003] Methods for recycling polymethyl(meth)acrylate include, for example, material recycling, in which the recovered molded bodies are subjected to a molding process again to produce new molded bodies; chemical recycling, in which the recovered molded bodies are heat-treated to thermally decompose (depolymerize) the polymethyl(meth)acrylate to recover the methyl(meth)acrylate, and the recovered methyl(meth)acrylate (sometimes referred to as recycled MMA or recycled MA) is used to produce new molded bodies; and thermal recycling, in which the recovered molded bodies are burned as fuel and the combustion energy is used directly as a heat source and further to generate electricity.

[0004] Furthermore, in response to the recent diversification of applications of poly(methyl (meth)acrylate), techniques for improving the quality of poly(methyl (meth)acrylate have been investigated. For example, as a polymerization apparatus suitable for obtaining high-quality poly(methyl(meth)acrylate), a polymerization apparatus that suppresses the formation of gelled matter in a reaction tank in which raw material monomers react with a polymerization initiator has been proposed (see Patent Document 1). [Prior art documents] [Patent documents]

[0005] [Patent Document 1] JP 2012-102190 A Summary of the Invention [Problem to be solved by the invention]

[0006] In addition to improving the polymerization process of the raw material monomers as described in Patent Document 1, there is a need for a method for improving the quality of polymethyl(meth)acrylate by optimizing the composition of the raw material monomers. In view of the above circumstances, an object of one embodiment of the present disclosure is to provide a composition that can give a molded article having excellent heat resistance, a polymer, a cured product, and a molded article obtained using the composition, and a method for producing polymethyl methacrylate using the composition. [Means for solving the problem]

[0007] Means for solving the above problems include the following embodiments. <1> Contains methyl methacrylate, methyl pivalate and water, The concentration of methyl pivalate is greater than 0 ppm by mass and not greater than 10,000 ppm by mass in the entire composition, A composition having a water concentration of greater than 0 ppm by mass and not greater than 10,000 ppm by mass of the total composition. <2> The content of methyl methacrylate in the entire composition is 85% by mass or more. <1> The composition described in <3> The content of methyl methacrylate in the entire composition is 90% by mass or more. <1> or <2> The composition described in <4> The methyl methacrylate comprises recycled methyl methacrylate or bio-derived methyl methacrylate; <1> ~ <3> The composition according to any one of claims 1 to 5. <5> Further containing (meth)acrylic acid esters other than methyl methacrylate, <1> ~ <4> The composition according to any one of claims 1 to 5. <6> Further comprising a polymer containing a structural unit derived from methyl methacrylate; <1> ~ <5> The composition according to any one of claims 1 to 5. <7> <1> ~ <6> A polymer comprising a structural unit derived from methyl methacrylate contained in the composition according to any one of claims 1 to 5. <8> <7> A molded article comprising the polymer according to claim 1. <9> <1> ~ <6> 2. A cured product of the composition according to claim 1. <10> <9> A molded article comprising the cured product according to claim 1. <11> <1> ~ <6> 2. A method for producing polymethyl methacrylate, comprising a step of polymerizing methyl methacrylate contained in the composition according to any one of claims 1 to 11. Effect of the Invention

[0008] According to one embodiment of the present disclosure, there are provided a composition that can give a molded article having excellent heat resistance, a polymer, a cured product, and a molded article obtained using the composition, and a method for producing polymethyl methacrylate using the composition. [Brief description of the drawings]

[0009] [Figure 1] 4 is a graph showing the relationship between the water concentration of the compositions prepared in the Examples and the 5% weight loss temperature of the cast plate. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] Hereinafter, an embodiment of the present invention will be described, however, the present invention is not limited to the following embodiment. In this specification, the numerical range indicated using "~" includes the numerical values ​​before and after "~" as the minimum and maximum values, respectively. In the present specification, the upper or lower limit of one numerical range may be replaced with the upper or lower limit of another numerical range. In addition, in the present specification, the upper or lower limit of the numerical range may be replaced with a value shown in the examples.

[0011] <Composition> The composition of the present disclosure contains methyl methacrylate, methyl pivalate, and water, wherein the concentration of methyl pivalate is greater than 0 ppm by mass and less than or equal to 10,000 ppm by mass of the entire composition, and the concentration of water is greater than 0 ppm by mass and less than or equal to 10,000 ppm by mass of the entire composition.

[0012] As shown in the examples described later, a molded article obtained by using a composition in which methyl pivalate and water are added to a composition containing methyl methacrylate exhibits superior heat resistance compared to a molded article obtained by using a composition in which only methyl pivalate is added to a composition containing methyl methacrylate. Specific examples of the heat resistance of a molded body include the 5% weight loss temperature and the glass transition temperature. The higher the 5% weight loss temperature of the molded body, the less likely the molded body is to thermally decompose, and the molded body can be judged to have excellent durability (thermal stability). The higher the glass transition temperature of the molded body, the more excellent the heat resistance of the molded body tends to be. A molded article obtained using the composition of the present disclosure has at least an improved 5% weight loss temperature or an improved glass transition temperature, or both.

[0013] (Methyl methacrylate) The compositions of the present disclosure include methyl methacrylate. In the present disclosure, "methyl methacrylate" refers to methyl methacrylate that is essentially free of impurities such as by-products generated during the synthesis of methyl methacrylate. However, the methyl methacrylate in the present disclosure is not limited thereto, provided that the purpose of the invention is not impaired. In other words, "methyl methacrylate" may contain impurities that cannot be completely removed by conventional purification methods, or may contain impurities at a content that cannot be detected by conventional detection methods.

[0014] The content of methyl methacrylate in the composition is not particularly limited and can be selected depending on the application of polymethyl methacrylate obtained using the composition, etc. The content of methyl methacrylate may be, for example, 85 mass% or more, 90 mass% or more, 95 mass% or more, or 99 mass% or more of the entire composition. When the content of methyl methacrylate in the composition is within the above range, it is preferable from the viewpoint of at least the heat resistance or transparency (light transmittance) of a polymer obtained by polymerizing the composition and a molded article containing the same.

[0015] The methyl methacrylate contained in the composition may be synthesized by a known synthesis method. The synthesis method is not particularly limited, and may be the ACH method, the C4 direct acid method, or the alpha method.

[0016] The methyl methacrylate contained in the composition may include recycled methyl methacrylate. In this disclosure, recycled methyl methacrylate means methyl methacrylate obtained by depolymerization of polymethyl methacrylate (a reaction in which a polymer is decomposed to produce a monomer). Depolymerization of polymethyl methacrylate can be effected, for example, by subjecting polymethyl methacrylate to a heat treatment. The source of polymethyl methacrylate, which is a raw material for regenerated methyl methacrylate, is not particularly limited as long as it is possible to recover methyl methacrylate. For example, the source of polymethyl methacrylate may be a molded body containing polymethyl methacrylate.

[0017] The methyl methacrylate included in the composition may include bio-derived methyl methacrylate. In the present disclosure, bio-derived methyl methacrylate means methyl methacrylate synthesized from a raw material of biological origin. The raw material of biological origin may be a raw material of plant origin or an animal origin, and is preferably a raw material derived from vegetable oil.

[0018] (Methyl pivalate) The compositions of the present disclosure include methyl pivalate. The concentration of methyl pivalate contained in the composition is not particularly limited, so long as it is more than 0 ppm by mass and not more than 10,000 ppm by mass of the entire composition.

[0019] As shown in the Reference Examples described later, a composition containing methyl methacrylate to which methyl pivalate has been added tends to have a lower residual MMA concentration in the resulting molded product than a composition containing methyl methacrylate but not containing methyl pivalate. A low residual MMA concentration in the molded product means that the molded product contains fewer unpolymerized components and is therefore superior in durability or heat resistance.

[0020] From the viewpoint of durability of the molded article, the concentration of methyl pivalate contained in the composition is preferably 10 ppm by mass or more of the total composition, more preferably 50 ppm by mass or more, and even more preferably 100 ppm by mass or more.

[0021] The upper limit of the concentration of methyl pivalate contained in the composition may be, for example, 5000 ppm by mass or less, 2000 ppm by mass or less, 1000 ppm by mass or less, or 600 ppm by mass or less.

[0022] (water) The compositions of the present disclosure include water. The concentration of water contained in the composition is not particularly limited, so long as it is more than 0 ppm by mass and 10,000 ppm by mass or less based on the total composition.

[0023] From the viewpoint of improving the heat resistance of the molded body, the concentration of water contained in the composition is preferably 10 ppm by mass or more of the total composition, more preferably 50 ppm by mass or more, even more preferably 100 ppm by mass or more, even more preferably 500 ppm by mass or more, and even more preferably 1000 ppm by mass or more.

[0024] The upper limit of the concentration of water contained in the composition may be, for example, less than 10,000 ppm by mass, 9,000 ppm by mass or less, 8,000 ppm by mass or less, or 7,000 ppm by mass or less.

[0025] If necessary, the composition may contain a component other than methyl methacrylate, methyl pivalate, and water. For example, the composition may contain a (meth)acrylic acid ester other than methyl methacrylate, a polymer containing a structural unit derived from methyl methacrylate, a low content component, or an additive, which will be described later.

[0026] ((Meth)acrylic acid ester) The composition may contain, in addition to methyl methacrylate, a (meth)acrylic acid ester other than methyl methacrylate (hereinafter also simply referred to as a (meth)acrylic acid ester). Specific examples of (meth)acrylic acid esters include methyl acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, n-butyl (meth)acrylate, sec-butyl (meth)acrylate, tert-butyl (meth)acrylate, cyclohexyl (meth)acrylate, benzyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, 2-hydroxyethyl (meth)acrylate, and cyclopentanyl (meth)acrylate. Among these, methyl acrylate or ethyl (meth)acrylate is preferred, and methyl acrylate is more preferred. These may be used alone or in combination of two or more. In the present disclosure, "(meth)acrylic acid ester" indicates that it may be either an acrylic acid ester or a methacrylic acid ester. The (meth)acrylic acid ester may be included in the composition as a by-product produced during the production of methyl methacrylate or during the regeneration treatment of polymethyl methacrylate, or may be intentionally mixed into the composition.

[0027] When the composition contains a (meth)acrylic acid ester, the concentration thereof is preferably 50,000 ppm by mass or less, more preferably 40,000 ppm by mass or less, and even more preferably 30,000 ppm by mass or less, of the entire composition. When the composition contains a (meth)acrylic acid ester, the concentration thereof may be 1 ppm by mass or more, 2 ppm by mass or more, or 5 ppm by mass or more of the total composition.

[0028] The composition may contain, in addition to methyl methacrylate, a polymer containing a structural unit derived from methyl methacrylate. This polymer may be a homopolymer of methyl methacrylate, or a copolymer of methyl methacrylate and other (meth)acrylic acid esters polymerizable therewith, as long as it contains a structural unit derived from methyl methacrylate. Examples of other (meth)acrylic acid esters polymerizable with methyl methacrylate include the same as those mentioned above.

[0029] (low content ingredients) The composition may contain minor components other than methyl pivalate or water, which may be present in the composition as by-products produced during the manufacture of methyl methacrylate or during the regeneration process of polymethyl methacrylate. In the present disclosure, a low content component means a component that is contained in the composition at a concentration of 10,000 ppm by mass or less.

[0030] Examples of low content components other than methyl pivalate or water that the composition may contain include carboxylic acid esters other than methyl pivalate, aromatic hydrocarbon compounds, aliphatic hydrocarbon compounds, alcohols, butyl acrylate, and the like. The composition may contain only one type or two or more types of low content components other than methyl pivalate or water.

[0031] Specific examples of carboxylate esters include methyl isobutyrate, methyl propionate, methyl 2,4-dimethyl-4-pentenoate, methyl 2-methyl-3-butenoate, methyl tiglate, methyl 3-methyl-3-butenoate, methyl 3-methyl-2-butenoate, dimethyl itaconate, and dimethyl 2-methyl-5-methylenehexanedioate. Specific examples of the aromatic hydrocarbon compound include toluene and styrene. Specific examples of the aliphatic hydrocarbon compounds include 1-octene and 1-octadecene.

[0032] When the composition contains low content components other than methyl pivalate or water, the concentration of each low content component is preferably 8000 ppm by mass or less of the total composition, more preferably 6000 ppm by mass or less, and even more preferably 5000 ppm by mass or less. When the composition includes low-content components other than methyl pivalate or water, the concentration of each low-content component may be 1 ppm or more, 2 ppm or more, or 5 ppm or more by weight of the total composition.

[0033] (Additives) If necessary, the composition may contain additives, such as a release agent, a polymerization regulator, a polymerization initiator, an ultraviolet absorber, and a colorant. The composition may contain only one type of additive, or two or more types of additives.

[0034] Examples of release agents that the composition may contain include higher fatty acid esters, higher fatty alcohols, higher fatty acids, higher fatty acid amides, higher fatty acid metal salts, and fatty acid derivatives. Specific examples of release agents include sodium di-(2-ethylhexyl)sulfosuccinate, stearyl alcohol, methyl stearate, and stearic acid amide.

[0035] The composition may contain one or more types of release agents. The content of the release agent in the composition can be, for example, 0.01% by mass to 1.0% by mass of the entire composition.

[0036] The polymerization regulator (additive for controlling the polymerization rate in the polymerization reaction) that may be contained in the composition may be any suitable polymerization regulator known in the art. For example, a compound capable of controlling the polymerization rate in the direction of decreasing the polymerization rate may be used as such a polymerization regulator. Specific examples of the polymerization regulator include mercaptan compounds such as n-butyl mercaptan and n-octyl mercaptan, terpenoid compounds such as limonene, myrcene, α-terpinene, β-terpinene, γ-terpinene, terpinolene, β-pinene, and α-pinene, and α-methylstyrene dimer.

[0037] The composition may contain one or more types of polymerization regulator. The content of the polymerization regulator in the composition can be, for example, 0.001% by mass to 0.5% by mass of the entire composition.

[0038] Polymerization initiators that the composition may contain include radical polymerization initiators, diacyl peroxide initiators, dialkyl peroxide initiators, peroxyester initiators, percarbonate initiators, and peroxyketal initiators.

[0039] Specific examples of radical polymerization initiators include azo compounds such as 1,1'-azobis(cyclohexane-1-carbonitrile), 2,2'-azobis(2,4,4-trimethylpentene), 2,2'-azobis(2-methylpropane), 2-cyano-2-propylazoformamide, 2,2'-azobis(2-hydroxymethylpropionate), 2,2'-azobis(2-methylbutyronitrile), 2,2'-azobisisobutyronitrile, 2,2'-azobis[2-(2-imidazolin-2-yl)propane], and dimethyl 2,2'-azobis(2-methylpropionate).

[0040] Specific examples of diacyl and dialkyl peroxide initiators include dicumyl peroxide, tert-butylcumyl peroxide, di-tert-butyl peroxide, benzoyl peroxide, and lauroyl peroxide.

[0041] Specific examples of peroxyester initiators include tert-butylperoxy-3,3,5-trimethylhexanoate, tert-butylperoxylaurate, tert-butylperoxyisobutyrate, tert-butylperoxyacetate, di-tert-butylperoxyhexahydroterephthalate, di-tert-butylperoxyazelate, tert-butylperoxy-2-ethylhexanoate, 1,1,3,3-tert-butylperoxyethylhexanoate, ... tetramethylbutylperoxy-2-ethylhexanoate, and tert-amylperoxy-2-ethylhexanoate.

[0042] Specific examples of percarbonate initiators include tert-butyl peroxy allyl carbonate, and tert-butyl peroxy isopropyl carbonate.

[0043] Specific examples of peroxyketal initiators include 1,1-di-tert-butylperoxycyclohexane, 1,1-di-tert-butylperoxy-3,3,5-trimethylcyclohexane, and 1,1-di-tert-hexylperoxy-3,3,5-trimethylcyclohexane.

[0044] The composition may contain one or more types of polymerization initiators. The content of the polymerization initiator in the composition can be, for example, 0.01% by mass to 5% by mass of the entire composition.

[0045] UV absorbers that the composition may contain include benzophenone UV absorbers, cyanoacrylate UV absorbers, benzotriazole UV absorbers, malonate UV absorbers, and oxalanilide UV absorbers.

[0046] Specific examples of ultraviolet absorbers include 2-(2'-hydroxy-5'-methylphenyl)benzotriazole, 2-hydroxy-4-n-octylbenzophenone, 2-(3-tert-butyl-2-hydroxy-5-methylphenyl)-5-chlorobenzotriazole, 2-(2-hydroxy-3,5-di-tert-pentylphenyl)benzotriazole, and 2,4-di-tert-butylphenyl-3,5-di-tert-butyl-4-hydroxybenzoate.

[0047] The composition may contain one or more types of ultraviolet absorbents. The content of the ultraviolet absorber in the composition can be, for example, 0.001% by mass to 1% by mass of the entire composition.

[0048] Colorants that the composition may contain include perylene dyes, perinone dyes, pyrazolone dyes, methine dyes, coumarin dyes, quinophthalone dyes, quinoline dyes, anthraquinone dyes, asdolapyridone dyes, thioindigo dyes, coumarin dyes, isoindolinone pigments, sichetopyrrolopyrrole pigments, condensed azo pigments, benzimidazolone pigments, dioxazine pigments, copper phthalocyanine pigments, and quinacridone pigments.

[0049] The composition may contain only one type of colorant, or two or more types of colorants. The content of the colorant in the composition is, for example, 1.0×10 -8 The content can be 0.5% by mass to 0.5% by mass.

[0050] When the composition contains additives, the total content thereof may be 15 mass % or less, 10 mass % or less, 5 mass % or less, or 1 mass % or less of the total composition. When the composition contains additives, the total content thereof may be 0.01 mass % or more, 0.05 mass % or more, or 0.1 mass % or more of the total composition.

[0051] The composition of the present disclosure may be used immediately after preparation, or may be stored before use. The storage conditions for storage are not particularly limited, but may be, for example, 0°C to 45°C. From the viewpoint of ensuring good quality, the storage temperature is preferably selected from the range of 0°C to 39°C, more preferably selected from the range of about 25°C±10°C, and even more preferably selected from the range of about 25°C to 30°C.

[0052] <Polymer, cured product and molded product> The polymer of the present disclosure is a polymer containing a structural unit derived from methyl methacrylate contained in the composition of the present disclosure. Here, the polymer is a polymer obtained by polymerizing the components involved in polymerization contained in the composition, and has a structural unit derived from the components involved in polymerization. The polymer of the present disclosure may contain a structural unit derived from methyl methacrylate contained in the composition of the present disclosure and a structural unit derived from another polymerization component. The weight average molecular weight of the polymer of the present disclosure is not particularly limited and can be selected according to the application of the polymer. The cured product of the present disclosure is a cured product of the composition of the present disclosure described above. Here, the cured product is a cured composition, and may contain components that are not involved in polymerization. However, depending on the method for curing the composition, it may be considered to be the same as the above-mentioned polymer (i.e., it does not contain components that are not involved in polymerization). The molded article of the present disclosure includes the polymer or cured product of the present disclosure. When the cured product can be regarded as the same as the polymer, the molded article includes a polymer of the composition of the present disclosure. The molded article is preferably a molded article including a cured product obtained by curing only the composition of the present disclosure. The molded article may be an object obtained by molding the polymer or the cured product into any shape.

[0053] The polymer, cured product, and molded article of the present disclosure contain methyl pivalate. The concentration of methyl pivalate is more than 0 ppm by mass and not more than 10,000 ppm by mass, based on the total mass of the polymer, cured product, or molded article. From the viewpoint of durability of the molded article, the concentration of methyl pivalate is preferably 10 ppm by mass or more, more preferably 50 ppm by mass or more, and even more preferably 100 ppm by mass or more, relative to the total mass of the polymer, cured product, or molded article of the present disclosure. The upper limit of the concentration of methyl pivalate may be, for example, 5000 ppm by mass or less, 2000 ppm by mass or less, 1000 ppm by mass or less, or 600 ppm by mass or less, relative to the total mass of the polymer, cured product, or molded article of the present disclosure.

[0054] The polymer, cured product, or molded product of the present disclosure contains water. The concentration of water is more than 0 mass ppm and 10000 mass ppm or less with respect to the total mass of the polymer, cured product, or molded product. From the viewpoint of improving the heat resistance of the polymer, cured product, or molded product, the concentration of the water is preferably 10 mass ppm or more, more preferably 50 mass ppm or more, even more preferably 100 mass ppm or more, even more preferably 500 mass ppm or more, and even more preferably 1000 mass ppm or more with respect to the total mass of the polymer, cured product, or molded product.

[0055] The upper limit of the water concentration contained in the polymer, cured product, or molded article may be, for example, less than 10,000 ppm by mass, 9,000 ppm by mass or less, 8,000 ppm by mass or less, or 7,000 ppm by mass or less, relative to the total mass of the polymer, cured product, or molded article.

[0056] From the viewpoint of heat resistance of the molded article, it is preferable that the concentration of methyl pivalate is more than 0 ppm by mass and not more than 10000 ppm by mass, and the concentration of water is more than 0 ppm by mass and not more than 10000 ppm by mass, relative to the total mass of the polymer, the cured product, or the molded article. The combination of the preferred ranges of the concentration of methyl pivalate and the concentration of water may be any combination of appropriate ranges of the respective concentration ranges described above. From the viewpoint of improving the 5% weight loss temperature and glass transition temperature of the molded article, the above concentrations are preferably such that the concentration of methyl pivalate is more than 0 ppm by mass and not more than 9000 ppm by mass, and the concentration of water is more than 0 ppm by mass and not more than 9000 ppm by mass. The combination of the preferred ranges of the concentration of methyl pivalate and the concentration of water may be any combination of appropriate ranges of the respective concentration ranges described above.

[0057] Whether the polymer and cured product of the present disclosure contain methyl methacrylate, methyl pivalate, water, or other components can be determined by known analytical methods, such as gas chromatography and liquid chromatography.

[0058] From the viewpoint of heat resistance of the molded product, the 5% weight loss temperature of the polymer, the cured product, and the molded product is preferably 278° C. or higher, more preferably 280° C. or higher, and even more preferably 282° C. or higher. In the present disclosure, the 5% weight loss temperature of the polymer, the cured product, or the molded product is measured by the method described in the Examples.

[0059] From the viewpoint of heat resistance of the molded article, the glass transition temperature of the polymer, cured product or molded article is preferably 108° C. or higher, more preferably 109° C. or higher, and even more preferably 110° C. or higher. In the present disclosure, the glass transition temperature of a polymer, a cured product, or a molded product is measured by the method described in the Examples.

[0060] From the viewpoint of durability of the molded article, the residual MMA concentration in the polymer, the cured product, and the molded article may be, for example, 9000 mass ppm or less. In the present disclosure, the residual MMA concentration in the polymer, the cured product, or the molded article is measured by the method described in the Examples.

[0061] <Production method of polymethyl methacrylate> The method for producing polymethyl methacrylate of the present disclosure includes a step of polymerizing the methyl methacrylate contained in the composition of the present disclosure. Here, the polymethyl methacrylate of the present disclosure includes a polymer obtained from the composition of the present disclosure and a cured product obtained from the composition.

[0062] The method for polymerizing methyl methacrylate contained in the composition is not particularly limited, and may be carried out by a known method, such as bulk polymerization, cell cast polymerization, solution polymerization, suspension polymerization, or emulsion polymerization.

[0063] Specifically, the composition of the present disclosure can be used to obtain a sheet (molded product) of a methyl methacrylate polymer by bulk polymerization, for example. In cell cast polymerization, the composition is heated under a predetermined heating condition to cause a polymerization reaction to proceed, thereby obtaining a cured product (molded product) of the composition.

[0064] In the method for polymerizing methyl methacrylate contained in the composition of the present disclosure or the method for producing a molded body, the heating temperature and heating time among the heating conditions can be set, for example, taking into consideration the type and content of the selected polymerization regulator, polymerization initiator, and / or other components.

[0065] In the cell cast polymerization, when producing a cured product and its molded article, the heating temperature can be, for example, 50° C. to 120° C. The heating time can be, for example, 1 hour to 20 hours. The heat treatment can be a heat treatment including a plurality of steps with different heating temperatures and / or heating times.

[0066] The cured product obtained by cell cast polymerization and its molded article can be produced, for example, by carrying out a heat treatment under heating conditions including the following steps 1 to 7.

[0067] Step 1: Raise the temperature from room temperature to 68°C over 20 minutes. Step 2: Hold at 68°C for 90 minutes. Step 3: Reduce the temperature from 68°C to 64°C over 20 minutes. Step 4: Hold at 64°C for 90 minutes. Step 5: Increase temperature from 64°C to 123°C over 10 minutes. Step 6: Hold at 123°C for 120 minutes. Step 7: The temperature is reduced from 123°C to room temperature over 78 minutes.

[0068] In the method for producing a cured product and a molded article thereof, by carrying out the above steps 1 to 7 in this order, heat generation during the polymerization reaction can be suppressed and the polymerization can be stably completed.

[0069] When the composition of the present disclosure is subjected to a heat treatment, for example, a cell casting method (cell casting polymerization) using a cell capable of defining an enclosed space of a predetermined shape inside can be applied to form a molded body of a predetermined shape. The manufacturing method of a molded body by the cell casting method will be specifically described below.

[0070] In manufacturing a green body by the cell casting method, a cell is first prepared. Here, an example of forming a green body that is a plate-like body (sometimes called a cast plate) will be described. Such a cell can be composed of at least two flat plate-like members and a sealing material (gasket) that is arranged so as to be sandwiched between the two flat plate-like members and can seal the gap between the two opposing flat plate-like members as an enclosed space.

[0071] The flat plate member may be in the form of a sheet or a belt. The flat plate member is made of a material that is not dissolved by the composition of the present disclosure, does not inhibit the polymerization reaction of the composition, and has sufficient heat resistance to the heating temperature in the heat treatment. Examples of suitable materials for the flat plate member include glass and metal.

[0072] As the sealing material, any suitable sealing material known in the art can be used. The sealing material is made of a material that is not dissolved by the composition of the present disclosure, does not inhibit the polymerization reaction of the composition, and has sufficient heat resistance to the heating temperature in the heat treatment. A specific example of a suitable sealing material is a gasket made of vinyl chloride resin.

[0073] Next, the composition of the present disclosure is injected into the gap (void) defined by the prepared cell by any suitable conventional method. After that, the cell is heat-treated under the heating conditions already described. The method of heat-treating the cell into which the composition of the present disclosure is injected is not particularly limited. The method of heat-treating the cell can be, as in the conventional cell casting method, a method of directly heat-treating the cell from the outside using a hot air circulating oven, an infrared heater, or the like, or a method of further providing any suitable conventional jacket on the outside of the cell and introducing a heat medium such as hot air, hot water, or water vapor into the jacket.

[0074] <Uses of polymethyl methacrylate and its molded bodies> The polymethyl methacrylate obtained from the composition of the present disclosure and its molded article are excellent in light transmittance, heat resistance, and weather resistance, and therefore can be suitably applied to various applications that may be exposed to the external environment and further to heat and light sources, such as lighting fixtures, automobile parts, signs, and building materials. EXAMPLES

[0075] Hereinafter, embodiments of the present disclosure will be described based on examples. The following examples are not intended to limit the present disclosure.

[0076] <Example 1> (Preparation of Composition) 99.87% by mass of methyl methacrylate was mixed with 0.03% by mass of methyl pivalate (manufactured by Tokyo Chemical Industry Co., Ltd.) and 0.1% by mass (1000 ppm by mass) of water to prepare composition 1. The obtained composition 1 was liquid. The composition of composition 1 is also shown in Table 1.

[0077] Composition 1 was subjected to a storage test including the following steps 1 to 7 in this order to obtain composition 1' after the storage test. The storage test was performed under accelerated conditions (60°C) to evaluate the stability after long-term storage.

[0078] Step 1: 25 mL of the composition is poured into the bottom of a pressure vessel ("TVS-N2" manufactured by Taiatsu Glass Industries Co., Ltd.). Step 2: Place a gasket between the top and bottom of the pressure vessel to seal it. Step 3: Feed nitrogen into the top tip of the pressure vessel and seal it at an internal pressure of 0.2 MPa. Check that the internal pressure does not change for one minute. Step 4: Release the internal pressure from the pressure vessel and install a stopcock at the top tip of the pressure vessel. Step 5: Place the pressure vessel in an oil bath set at 60°C. Step 6: Store in oil bath for 24 or 18 hours. Step 7: Remove the pressure vessel from the oil bath and place it in ice-cold water to rapidly cool it.

[0079] Composition 1' (99.84 parts by mass), sodium di-(2-ethylhexyl)sulfosuccinate (0.05 parts by mass) as a release agent, terpinolene (0.03 parts by mass) as a polymerization regulator, and 2,2'-azobisisobutyronitrile (0.08 parts by mass) as a polymerization initiator were mixed to obtain composition 1'' for forming a molded body (cast plate). The obtained composition 1'' was in a liquid state.

[0080] (Making cast plates) A cell was prepared in which a 3.8 mm thick polyvinyl chloride resin gasket was sandwiched between two opposing glass plates, and a gap could be defined by the polyvinyl chloride resin gasket and the two glass plates. Composition 1'' was poured into the gap in this cell. The cell into which composition 1'' was poured was placed in an oven, and composition 1'' was polymerized by performing a heat treatment under heating conditions including the following steps 1 to 7 in this order, to produce a cast plate that was a 3 mm thick, 100 mm square molded body of a methyl methacrylate polymer.

[0081] Step 1: Raise the temperature from room temperature to 68°C over 20 minutes. Step 2: Hold at 68°C for 90 minutes. Step 3: Reduce the temperature from 68°C to 64°C over 20 minutes. Step 4: Hold at 64°C for 90 minutes. Step 5: Increase temperature from 64°C to 123°C over 10 minutes. Step 6: Hold at 123°C for 120 minutes. Step 7: The temperature is lowered from 123°C to room temperature over 90 minutes.

[0082] <Examples 2 to 4, Comparative Example 1> Cast plates of Examples 2 to 4 and Comparative Example 1 were produced in the same manner as in Example 1, except that compositions in which the amount of water added was changed to the values ​​shown in Table 1 were used.

[0083] (Measurement of 5% weight loss temperature) The 5% weight loss temperatures of the cast plates produced in Examples 1 to 4 and Comparative Example 1 were measured by the following method. The results are shown in Table 1 and FIG.

[0084] The cast plate was crushed to a diameter or length of each side of 0.5 mm or less, and 9.3 mg of the crushed material was placed on an aluminum pan (Hitachi High-Tech Science Corp., "P / N SSC000E030 Open Sample Pan", diameter 5 mm). Using a thermogravimetry / differential thermal analyzer (Hitachi High-Tech Science Corp., "TG / DTA7200"), the weight change of the crushed material was measured while heating it from 45°C to 520°C under conditions of a nitrogen gas flow rate of 200 mL / min and a heating rate of 10°C / min. As a result, the weight of the crushed material decreased as the temperature increased. The weight of the crushed material at the start of the measurement (45°C) was taken as 100% by weight, and the temperature at which the weight of the crushed material decreased to 95% by weight (5% weight loss temperature) was calculated.

[0085] [Table 1]

[0086] (Measurement of glass transition temperature (Tmg)) The glass transition temperatures of the cast plates produced in Examples 2 and 4 and Comparative Example 1 were measured by the following method. The results are shown in Table 2.

[0087] The cast plate was crushed to a diameter or each side length of 0.5 mm or less, and the crushed material obtained was used as a sample, and the glass transition temperature (° C.) was measured in accordance with JIS-K7121. The glass transition temperature was measured using a differential scanning calorimeter ("DSC7020" manufactured by Hitachi High-Tech Science Corporation) at a nitrogen gas flow rate of 50 mL / min. Specifically, the temperature was raised from room temperature (23°C) to 150°C at 20°C / min (first heating), and then held at 150°C for 5 minutes to completely melt the sample.The temperature was then lowered from 150°C to -35°C at 10°C / min, and held at -35°C for 1 minute.The temperature was then raised again to 210°C at 10°C / min (second heating).

[0088] Of the DSC curves obtained from the above temperature profile, the intersection point (midpoint glass transition temperature) between the step-like change partial curve during the second heating period and a straight line equidistant in the vertical direction from the two baseline extensions was determined as the glass transition temperature (°C).

[0089] [Table 2]

[0090] As shown in Tables 1 and 2, the cast plates made from the compositions containing methyl methacrylate, methyl pivalate and water had at least one of a higher 5% weight loss temperature and a higher glass transition temperature than the cast plates made from the compositions containing methyl methacrylate and methyl pivalate but not water, and thus exhibited excellent heat resistance.

[0091] <Reference examples 1~4> A composition was prepared by adding methyl pivalate in the amount shown in Table 3 to methyl methacrylate. The composition was subjected to the same storage test as in the Examples. Cast plates were prepared using the compositions after the storage test in the same manner as in the Examples, and the residual MMA concentration of the cast plates was measured by the method described below. The results are shown in Table 3.

[0092] (Measurement of residual MMA concentration) 0.5 g was cut from the cast plate and precisely weighed, and 10 cc of acetone (special grade) was added to dissolve it. 1 cc of an internal standard solution (a solution of 1% methyl isobutyl ketone (MIBK) dissolved in methanol) was added to the obtained acetone solution and stirred. 30 cc of methanol was added to the obtained mixed solution to reprecipitate the methyl methacrylate polymer. The supernatant solution was then collected as a sample solution. The amount of residual methyl methacrylate contained in the sample solution was measured using the following gas chromatography device.

[0093] (Measurement conditions) Equipment: GC-2010 Plus (manufactured by Shimadzu Corporation) Column: DB-1 (Agilent Technologies, Inc.) Detector: FID 2010 Plus (Shimadzu Corporation) Column oven conditions Initial temperature: 40℃ (hold time 1 minute) Heating rate: 8℃ / min Intermediate temperature: 120℃ (hold time 0 minutes) Heating rate: 20℃ / min Final temperature: 250℃ (hold time 5 minutes) Sample vaporization conditions Vaporization chamber temperature: 300℃ Carrier gas: Helium Pressure: 50kPa Total flow: 58.3mL / min Column flow rate: 1.08 mL / min Linear speed: 31.1cm / sec Purge dose: 3.0mL / min Split ratio: 50 Detector conditions Detector temperature: 300℃ Sampling rate: 40msec Make-up gas: N2 Make-up flow rate: 30mL / min H2 flow rate: 40mL / min Air flow rate: 400mL / min Autosampler Conditions Injection volume: 1μL

[0094] The peak area (a1) corresponding to methyl methacrylate and the peak area (b1) corresponding to methyl isobutyl ketone detected when the sample solution was measured under the above measurement conditions were measured. From these peak areas, the peak area ratio A (=a1 / b1) was calculated.

[0095] A standard sample having a mass ratio of methyl methacrylate content to methyl isobutyl ketone content of W0 (known) was measured under the above measurement conditions, and the peak area (a0) corresponding to the detected methyl methacrylate and the peak area (b0) corresponding to methyl isobutyl ketone were measured. From these peak areas, the peak area ratio A0 (=a0 / b0) was calculated. Next, the factor f (=W0 / A0) was calculated from the peak area ratio A0 and the above mass ratio W0.

[0096] Next, the mass ratio W of methyl methacrylate to methyl isobutyl ketone contained in the sample solution was calculated by multiplying the peak area ratio A by the factor f. The residual MMA concentration (ppm by mass) of the cast plate was calculated from the calculated mass ratio W and the mass of the cast plate used to prepare the sample solution.

[0097] [Table 3]

[0098] As shown in Table 3, the cast plates of Reference Examples 2 to 4, which were prepared using compositions in which methyl pivalate was added to methyl methacrylate, had lower residual MMA concentrations and exhibited excellent durability compared to the cast plate prepared using the composition of Reference Example 1 in which methyl pivalate was not added to methyl methacrylate.

Claims

1. Contains methyl methacrylate, methyl pivalate and water, The content of methyl methacrylate in the entire composition is 85% by mass or more, The concentration of methyl pivalate is more than 0 ppm by mass and not more than 5000 ppm by mass of the total composition, A composition having a water concentration of 500 ppm by mass or more and 10,000 ppm by mass or less based on the total composition.

2. The composition according to claim 1, wherein the content of methyl methacrylate is 90% by mass or more of the total composition.

3. 2. The composition of claim 1, wherein the methyl methacrylate comprises recycled methyl methacrylate or bio-derived methyl methacrylate.

4. The composition of claim 1 further comprising a (meth)acrylic acid ester other than methyl methacrylate.

5. The composition of claim 1 further comprising a polymer comprising structural units derived from methyl methacrylate.

6. A cured product of the composition according to any one of claims 1 to 5.

7. A molded article comprising the cured product according to claim 6.

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