Composition, cured product and molded article

Abstract

The present invention provides a composition capable of controlling the thermal decomposition property of a molded article, a polymer, a cured product and a molded article obtained by using the composition, and a method for producing polymethyl methacrylate. [Solution] A composition containing methyl methacrylate, methyl pivalate, and methyl isobutyrate, wherein the content of methyl pivalate in the composition is more than 0 ppm by mass and not more than 50,000 ppm by mass, and the content of methyl isobutyrate in the composition is more than 0 ppm by mass and not more than 2,000 ppm by mass; a polymer, a cured product, and a molded product obtained using this composition; and a method for producing polymethyl methacrylate by polymerizing methyl methacrylate in the above composition.

Description

[Technical field]

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

[0002] Polymethyl(meth)acrylate, such as polymethyl methacrylate obtained by polymerizing methyl methacrylate, 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 polymethyl(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 then 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 polymers such as polymethyl methacrylate, a polymerization apparatus that suppresses the formation of gelled products 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] Incidentally, for molded articles to be chemically recycled after use, the required quality level according to the application is becoming higher. On the other hand, if the thermal stability of the molded article is made too high, the suitability for recycling is poor. Therefore, it is important to achieve a good balance between the required quality according to the application and the suitability for recycling in terms of the quality of the molded article containing polymethyl (meth)acrylate. As an index of such quality, the thermal decomposition property of the molded article is attracting attention.

[0007] In view of the above circumstances, an object of the present disclosure is to provide a composition capable of controlling the thermal decomposition of a molded article, a polymer, a cured product, and a molded article obtained by using the composition. Another object of the present disclosure is to provide a method for producing polymethyl methacrylate. [Means for solving the problem]

[0008] Means for solving the above problems include the following embodiments. <1> A composition comprising methyl methacrylate, methyl pivalate, and methyl isobutyrate, the content of the methyl pivalate in the entire composition is more than 0 ppm by mass and 50,000 ppm by mass or less, A composition, wherein the content of the methyl isobutyrate in the entire composition is more than 0 ppm by mass and 2000 ppm by mass or less. <2> The content of the methyl methacrylate in the entire composition is 85% by mass or more. <1> The composition described in <3> The content of the methyl methacrylate in the entire composition is 90% by mass or more. <1> or <2> The composition described in <4> The content of methyl isobutyrate is less than 2000 ppm by mass; <1> ~ <3> The composition according to any one of claims 1 to 5. <5> The methyl methacrylate comprises recycled methyl methacrylate or bio-derived methyl methacrylate; <1> ~ <4> The composition according to any one of claims 1 to 5. <6> Further containing the (meth)acrylic acid ester other than methyl methacrylate, <1> ~ <5> The composition according to any one of claims 1 to 5. <7> the above <1> ~ <6> A polymer comprising a structural unit derived from the methyl methacrylate contained in the composition according to any one of claims 1 to 5. <8> the above <7> A molded article comprising the polymer according to claim 1. <9> the above <1> ~ <6> 2. A cured product of the composition according to claim 1. <10> the above <9> A molded article comprising the cured product according to claim 1. <11> the above <1> ~ <6> 2. A method for producing polymethyl methacrylate, comprising the step of polymerizing the methyl methacrylate contained in the composition according to claim 1. Effect of the Invention

[0009] The present disclosure provides a composition capable of controlling the thermal decomposition of a molded article, a polymer, a cured product, and a molded article obtained by using the composition. The present disclosure also provides a method for producing polymethyl methacrylate using the composition, for example. [Brief description of the drawings]

[0010] [Figure 1] FIG. 1 is a graph showing the relationship between the methyl isobutyrate content of the compositions prepared in the examples (not stored after preparation) and the 5% weight loss temperature of cast plates formed from the compositions. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0011] Hereinafter, one embodiment of the present disclosure will be described, however, the present disclosure is not limited to the following embodiment. In this disclosure and this specification, "(meth)acrylic" means one or both of acrylic and methacrylic. The same applies to "(meth)acrylic acid ester" and "(meth)acrylic acid". In addition, in this disclosure and this specification, when the content, physical properties, etc. are described by showing a numerical range, when the upper limit and lower limit of the numerical range are described separately, any of the upper limit and lower limit can be appropriately combined to form a specific numerical range. On the other hand, when multiple numerical ranges expressed with "~" are set and described, the upper limit and lower limit forming the numerical range are not limited to the specific combination described before and after "~" as a specific numerical range, and can be a numerical range that appropriately combines the upper limit and lower limit of each numerical range. Note that in this disclosure and this specification, the numerical range expressed with "~" means a range that includes the numerical values ​​described before and after "~" as the lower limit and upper limit.

[0012] <Composition> The composition of the present disclosure (the composition in one embodiment of the present disclosure) contains methyl methacrylate, methyl pivalate, and methyl isobutyrate, and the content of methyl pivalate in the entire composition is more than 0 ppm by mass and not more than 50,000 ppm by mass, and the content of methyl isobutyrate in the entire composition is more than 0 ppm by mass and not more than 2,000 ppm by mass.

[0013] As shown in the examples described later, by adding methyl pivalate and methyl isobutyrate to a composition containing methyl methacrylate and then setting the content of methyl pivalate and methyl isobutyrate within the above-mentioned specific range, the 5% weight loss temperature of a molded body formed using the composition can be improved while maintaining the glass transition point of the molded body (polymer, specifically, homopolymer or copolymer of methyl methacrylate). As a result, the composition of the present disclosure is less susceptible to thermal decomposition, and can impart the desired thermal stability when formed into a molded body, thereby improving heat resistance. On the other hand, polymethyl methacrylate contained in a molded body formed using the composition of the present disclosure maintains thermal decomposition even if its thermal stability is increased. Therefore, the composition of the present disclosure can realize a property of having both high thermal stability and excellent recyclability after use when formed into a molded body, and can control the thermal decomposition of the molded body.

[0014] (Methyl methacrylate) The compositions of the present disclosure contain methyl methacrylate. In the present disclosure, compounds such as methyl methacrylate generally refer to compounds as a single component, but may contain inevitable impurities. In addition, in the present disclosure, each compound, particularly methyl methacrylate, can be used as a mixture with methyl pivalate, methyl isobutyrate, other components (particularly low content components) described later, solvents, etc., in addition to inevitable impurities, as long as the purpose of the present disclosure is not impaired and the composition, cured product, or molded product of the present disclosure (components and contents) are satisfied.

[0015] The content of methyl methacrylate in the composition (of the entire composition) is not particularly limited and can be appropriately determined depending on the use of polymethyl methacrylate obtained by using the composition. The content of methyl methacrylate is not particularly limited, but is preferably 85% by mass or more of the entire composition (of the total mass of the composition), more preferably 90% by mass or more, and can be 95% by mass or more or 99% by mass or more, in terms of maintaining excellent properties of polymethyl methacrylate and its molded body.

[0016] The methyl methacrylate contained in the composition may include methyl methacrylate synthesized by a known synthesis method (sometimes referred to as "synthetic methyl methacrylate"). The synthesis method is not particularly limited, and may be any of the ACH method, the C4 direct oxidation method, and the alpha method.

[0017] The methyl methacrylate included in the composition may include recycled methyl methacrylate. In this disclosure, "recycled methyl methacrylate" refers to methyl methacrylate obtained by depolymerization of polymethyl methacrylate (a reaction in which a polymer is decomposed to produce monomers). The depolymerization of polymethyl methacrylate can be carried out, for example, by heating the polymethyl methacrylate to a temperature equal to or higher than its thermal decomposition temperature. 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.

[0018] 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, but is preferably a raw material derived from vegetable oil.

[0019] The methyl methacrylate contained in the composition of the present disclosure may contain at least one of synthetic methyl methacrylate, recycled methyl methacrylate, and bio-derived methyl methacrylate. From the viewpoint of addressing the above-mentioned resource price hike and environmental issues, the composition of the present disclosure preferably contains at least one of recycled methyl methacrylate and bio-derived methyl methacrylate as the methyl methacrylate. In the present disclosure, the content of each of synthetic methyl methacrylate, recycled methyl methacrylate, and bio-derived methyl methacrylate in the total mass of methyl methacrylate contained in the composition of the present disclosure is not particularly limited and can be determined appropriately.

[0020] (Methyl pivalate) The composition of the present disclosure contains methyl pivalate. The content of methyl pivalate in the entire composition is more than 0 ppm by mass and 50,000 ppm by mass or less, based on the total mass of the composition. In the composition of the present disclosure, the coexistence of methyl pivalate and methyl isobutyrate, which will be described later, in a predetermined content relative to methyl methacrylate can improve the storage stability of the composition or the thermal stability of a molded article.

[0021] The content of methyl pivalate in the entire composition can be appropriately determined within the above range. For example, from the viewpoint of the storage stability of the composition and / or the control of the thermal decomposition property of the molded article, the content 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 composition.

[0022] On the other hand, the upper limit of the content of methyl pivalate in the entire composition can be appropriately determined within the above range, and can be, for example, 2000 ppm by mass or less, preferably 1000 ppm by mass or less, and more preferably 600 ppm by mass or less.

[0023] (Methyl isobutyrate) The composition of the present disclosure contains methyl isobutyrate. The content of methyl isobutyrate in the entire composition is more than 0 ppm by mass and 2000 ppm by mass or less, based on the total mass of the composition. In the composition of the present disclosure, the coexistence of methyl isobutyrate and the above-mentioned methyl pivalate at a predetermined content relative to methyl methacrylate can improve the storage stability of the composition or improve the thermal stability of a molded article.

[0024] The content of methyl isobutyrate in the entire composition can be appropriately determined within the above range. For example, from the viewpoint of the storage stability of the composition and / or the control of the thermal decomposition properties of the molded body, it 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 composition.

[0025] On the other hand, the upper limit of the methyl isobutyrate content in the entire composition can be appropriately determined within the above range. For example, from the viewpoint of increasing the 5% weight loss temperature of the molded body to control the thermal decomposition (enhancing thermal stability), it can be less than 2000 ppm by mass relative to the total mass of the composition, and taking into consideration the thermal decomposition of the molded body, it is preferably 1800 ppm by mass or less, more preferably 1500 ppm by mass or less, and even more preferably 1000 ppm by mass or less.

[0026] The composition of the present disclosure may contain components other than methyl methacrylate, methyl pivalate, and methyl isobutyrate (hereinafter, sometimes referred to as "other components"). Examples of the other components include (meth)acrylic esters, polymers described below, low content components, and additives.

[0027] ((Meth)acrylic acid ester) The composition of the present disclosure may contain a (meth)acrylic acid ester other than methyl methacrylate (also simply referred to as a "(meth)acrylic acid ester"). The (meth)acrylic acid ester is not particularly limited, but examples thereof 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 acrylate is preferred, and methyl acrylate is more preferred. The composition of the present disclosure may contain one or more (meth)acrylic acid esters. The (meth)acrylic acid ester contained in the composition of the present disclosure is usually (intentionally) mixed separately from the above-mentioned methyl methacrylate, etc., but may also be a by-product generated during the synthesis of methyl methacrylate or the regeneration treatment of polymethyl methacrylate.

[0028] When the composition of the present disclosure contains a (meth)acrylic acid ester, its content is not particularly limited and can be appropriately determined.For example, the upper limit of the content of the (meth)acrylic acid ester is preferably 50000 mass ppm or less of the entire composition, more preferably 40000 mass ppm or less, and even more preferably 30000 mass ppm or less.On the other hand, the lower limit of the content of the (meth)acrylic acid ester can be 1 mass ppm or more of the entire composition, and may be 2 mass ppm or more or 5 mass ppm or more.

[0029] (low content ingredients) The compositions of the present disclosure may contain minor components other than methyl pivalate and methyl isobutyrate. The minor components 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, the term "low content component" refers to a component contained in the composition at a content of 10,000 ppm by mass or less. However, the above-mentioned (meth)acrylic acid ester and the additives described below are not included in the low content component even if their content in the composition is 10,000 ppm by mass or less.

[0030] Examples of low content components include carboxylate compounds, aromatic hydrocarbon compounds, aliphatic hydrocarbon compounds, and alcohol compounds. The composition of the present disclosure may contain only one type of low content component or two or more types of low content components.

[0031] Examples of carboxylate compounds include 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. Aromatic hydrocarbon compounds include, for example, toluene and styrene. Aliphatic hydrocarbon compounds include, for example, 1-octene and 1-octadecene. Examples of the alcohol compound include methanol, ethanol, propanol (including isomers), and butanol (including isomers).

[0032] When the composition of the present disclosure contains low content components, the content of each compound group is not particularly limited and can be appropriately determined.For example, the upper limit of the content of each compound group is preferably 8000 mass ppm or less of the entire composition, more preferably 6000 mass ppm or less, and even more preferably 5000 mass ppm or less.On the other hand, the lower limit of the content of each compound group can be 1 mass ppm or more of the entire composition, and may be 2 mass ppm or more or 5 mass ppm or more.

[0033] (Additives) The composition of the present disclosure may contain additives as necessary. The additives are not particularly limited, and examples thereof include a release agent, a polymerization regulator, a polymerization initiator, an ultraviolet absorber, and a colorant. The composition of the present disclosure may contain one or more types of additives.

[0034] Examples of the release agent 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 the release agent include sodium di-(2-ethylhexyl)sulfosuccinate, stearyl alcohol, methyl stearate, and stearic acid amide. The release agent contained in the composition of the present disclosure may be of one type or of two or more types. The content of the release agent is not particularly limited and can be determined appropriately, and can be, for example, 0.01 to 1.0% by mass of the entire composition.

[0035] As the polymerization regulator (an additive for controlling the polymerization rate in a polymerization reaction), any suitable polymerization regulator known in the art can be used. As such a polymerization regulator, for example, a compound capable of controlling the polymerization rate in the direction of decreasing the polymerization rate can be used. 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. The polymerization regulator contained in the composition of the present disclosure may be one type or two or more types. The content of the polymerization regulator is not particularly limited and can be determined appropriately, and can be, for example, 0.001 to 0.5% by mass of the entire composition.

[0036] Examples of the polymerization initiator include a radical polymerization initiator, a diacyl peroxide initiator, a dialkyl peroxide initiator, a peroxy ester initiator, a percarbonate initiator, and a peroxy ketal initiator.

[0037] 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).

[0038] Specific examples of diacyl peroxide initiators and dialkyl peroxide initiators include, for example, dicumyl peroxide, tert-butylcumyl peroxide, di-tert-butyl peroxide, benzoyl peroxide, and lauroyl peroxide.

[0039] 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-tetramethylbutylperoxy-2-ethylhexanoate, and tert-amylperoxy-2-ethylhexanoate.

[0040] Specific examples of percarbonate initiators include, for example, tert-butyl peroxy allyl carbonate, and tert-butyl peroxy isopropyl carbonate.

[0041] Specific examples of peroxyketal initiators include, for example, 1,1-di-tert-butylperoxycyclohexane, 1,1-di-tert-butylperoxy-3,3,5-trimethylcyclohexane, and 1,1-di-tert-hexylperoxy-3,3,5-trimethylcyclohexane.

[0042] The polymerization initiator contained in the composition of the present disclosure may be one type or two or more types. The content of the polymerization initiator is not particularly limited and can be appropriately determined, for example, within the range of 0.01 to 5% by mass of the entire composition.

[0043] Examples of ultraviolet absorbers include benzophenone ultraviolet absorbers, cyanoacrylate ultraviolet absorbers, benzotriazole ultraviolet absorbers, malonic acid ester ultraviolet absorbers, and oxalanilide ultraviolet absorbers. 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. The composition may contain one or more types of ultraviolet absorbents. The content of the ultraviolet absorbing agent is not particularly limited and can be determined appropriately, and can be, for example, 0.001 to 1% by mass of the entire composition.

[0044] Examples of colorants 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. The colorant contained in the composition of the present disclosure may be one type or two or more types. The content of the colorant is not particularly limited and can be determined appropriately. For example, -8 It can be up to 0.5% by mass.

[0045] When the composition of the present disclosure contains two or more kinds of additives, the total content is not particularly limited and can be determined appropriately.The upper limit of the total content of additives can be, for example, 15% by mass or less of the entire composition, but can also be set appropriately to 10% by mass or less, 5% by mass or less, or 1% by mass or less.On the other hand, the lower limit of the total content of additives can be, for example, 0.01% by mass or more of the entire composition, but can also be set appropriately to 0.05% by mass or more or 0.1% by mass or more.

[0046] (Preparation of Composition) The composition of the present disclosure can be produced by a known method, and can usually be prepared by mixing methyl methacrylate, methyl pivalate, methyl isobutyrate, and other components as appropriate in the ratios that result in the above-mentioned respective contents. The mixing method is not particularly limited, and each component may be mixed at once or sequentially. When mixed sequentially, the mixing order is not particularly limited. In addition, the mixing conditions are not particularly limited and can be determined as appropriate, but it is preferable to select conditions that suppress the volatilization of methyl isobutyrate and the like. In the present disclosure, as described above, methyl pivalate, methyl isobutyrate, and other components can be used as a mixture with methyl methacrylate, and in this case, the amount of methyl pivalate, etc., mixed is determined in consideration of the content in the mixture with methyl methacrylate used. Note that, for methyl pivalate, etc., when the content in the mixture with methyl methacrylate used satisfies the content in the composition of the present disclosure, there is no need to adjust the content of methyl pivalate, etc.

[0047] The composition of the present disclosure may be used immediately after preparation, or may be stored before use. Since the composition of the present disclosure exhibits excellent storage stability, it is also a preferred embodiment to store the composition once after preparation before use. The storage conditions for storing the composition of the present disclosure are not particularly limited, but for example, the storage temperature can be 0 to 45°C. From the viewpoint of ensuring good quality, the storage temperature is preferably selected from the range of 0 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 to 30°C. The storage time can be appropriately determined depending on the state, quality, etc. of the composition of the present disclosure.

[0048] <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 described above. Here, the polymer is a polymer obtained by polymerizing a component involved in polymerization contained in the composition, and has a structural unit derived from the component 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. Examples of the other polymerization components include the above-mentioned (meth)acrylic acid esters. The polymer of the present disclosure is preferably polymethyl methacrylate. This polymethyl methacrylate is produced by the method for producing polymethyl methacrylate of the present disclosure described below. 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.

[0049] 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 and further the composition of the composition, it may be regarded as the same as the polymer of the present disclosure described above (i.e., it does not contain components that are not involved in polymerization). In the present disclosure, the curing method may be a method that is usually applied to the composition, and includes a polymerization method and a crosslinking method, and is preferably a polymerization method. The properties of the cured product of the present disclosure are not particularly limited, but it is usually a non-molded product that is not molded into a predetermined shape. The cured product of the present disclosure is manufactured by a manufacturing method of a cured product described later.

[0050] The molded article of the present disclosure includes the polymer or cured product of the present disclosure described above. When the cured product can be regarded as the same as the polymer, the molded article of the present disclosure includes the polymer of the composition of the present disclosure. The molded article of the present disclosure is preferably a molded article containing a cured product obtained by curing only the composition of the present disclosure. The molded article is an object obtained by molding a polymer or a cured product into a form, shape and size suitable for the application by various known molding methods. Examples of the shape include a sheet shape (including a film shape, a strip shape, and a plate shape, which may be long or short (leaf shape)), a block shape, and various three-dimensional shapes. The molded article of the present disclosure is manufactured by the manufacturing method of a molded article described later.

[0051] In the cured product and molded article of the present disclosure, the content of the polymer of the present disclosure can be appropriately determined depending on the content of methyl methacrylate in the composition of the present disclosure, the curing conditions and molding conditions of the composition, etc. In one embodiment, the cured product or molded product of the present disclosure may contain (remain) residual (unpolymerized) methyl methacrylate, methyl pivalate, methyl isobutyrate, and other components. In another embodiment of the molded product of the present disclosure, it is preferable that the above-mentioned components remaining during use are removed to an extent that meets the required properties of the application.

[0052] In one embodiment of the present disclosure, when the cured product or molded product of the present disclosure contains methyl pivalate, the content of methyl pivalate is not particularly limited, and can be, for example, more than 0 ppm by mass and 50000 ppm by mass or less with respect to the total mass (100 parts by mass) of the cured product or molded product. From the viewpoint of controlling the thermal decomposition of the molded product, for example, from the viewpoint of increasing the thermal decomposition of the cured product or molded product, the content of methyl pivalate is, for example, preferably 10 ppm by mass or more with respect to the total mass of the cured product or molded product, more preferably 50 ppm by mass or more, and even more preferably 100 ppm by mass or more. On the other hand, from the viewpoint of increasing the 5% weight loss temperature of the cured product or molded product, the content of methyl pivalate can be, for example, 2000 ppm by mass or less with respect to the total mass of the cured product or molded product, preferably 1000 ppm by mass or less, and more preferably 600 ppm by mass or less.

[0053] In one embodiment of the present disclosure, when the cured product or molded product of the present disclosure contains methyl isobutyrate, the content of methyl isobutyrate is not particularly limited, and can be, for example, more than 0 ppm by mass and 2000 ppm by mass or less with respect to the total mass (100 parts by mass) of the cured product or molded product. From the viewpoint of controlling the thermal decomposition of the molded product, for example, from the viewpoint of increasing the thermal decomposition of the cured product or molded product, the content of methyl isobutyrate is, for example, preferably 10 ppm by mass or more with respect to the total mass of the cured product or molded product, more preferably 50 ppm by mass or more, and even more preferably 100 ppm by mass or more. On the other hand, from the viewpoint of increasing the 5% weight loss temperature of the cured product or molded product, the content of methyl isobutyrate can be, for example, 2000 ppm by mass or less with respect to the total mass of the cured product or molded product, preferably less than 2000 ppm by mass, more preferably 1800 ppm by mass or less, even more preferably 1500 ppm by mass or less, and particularly preferably 1000 ppm by mass or less.

[0054] When the cured product or molded article of the present disclosure contains the above-mentioned other components, the content of each component is not particularly limited and can be set to, for example, the same range as the content of each component in the entire composition, except for components that decompose or volatilize during polymerization or molding, such as polymerization regulators and polymerization initiators.

[0055] Whether or not the cured product or molded article of the present disclosure contains methyl methacrylate, methyl pivalate, methyl isobutyrate, and other components can be determined by known analytical methods, such as gas chromatography and liquid chromatography.

[0056] <Methods for Producing Polymer, Cured Product, and Molded Product> A method for producing the polymer (polymethyl methacrylate) of the present disclosure includes a step of polymerizing the methyl methacrylate contained in the composition of the present disclosure described above. The method for polymerizing the methyl methacrylate contained in the composition of the present disclosure is not particularly limited, and includes known techniques, such as bulk polymerization, solution polymerization, suspension polymerization, emulsion polymerization, etc. In the polymerization step, other polymerization components may be copolymerized when polymerizing the methyl methacrylate contained in the composition of the present disclosure. In the method for producing a polymer of the present disclosure, it is sufficient that methyl pivalate and methyl isobutyrate coexist in a predetermined content (mixing amount) when polymerizing methyl methacrylate, and the method is not limited to a method of performing the above-mentioned polymerization step using a composition of the present disclosure prepared in advance. For example, the method for producing a polymer of the present disclosure includes a method of performing a step of mixing methyl pivalate and methyl isobutyrate in a predetermined mixing amount with methyl methacrylate without preparing the composition of the present disclosure in advance, forming a polymerization system corresponding to the composition of the present disclosure, and polymerizing methyl methacrylate. Therefore, in this disclosure and this specification, when referring to a polymer obtained by using the composition of the present disclosure or a polymer formed by using the composition of the present disclosure, as described above, it includes a polymer obtained in at least two aspects, that is, an aspect in which the composition of the present disclosure is used and an aspect in which the composition of the present disclosure is formed in a polymerization system. This also applies to the cured product and molded product described later.

[0057] The cured product of the present disclosure can be produced by any of the known methods and conditions depending on the curing method, etc., and can be produced, for example, by the above-mentioned polymerization step.

[0058] The molded article of the present disclosure can be produced by various known molding methods. For example, the composition of the present disclosure can be bulk polymerized to polymerize and mold methyl methacrylate in the composition of the present disclosure to produce a sheet-shaped molded article. In addition, in cell cast polymerization, the composition of the present disclosure can be heated under a predetermined heating condition to proceed with the polymerization reaction, thereby obtaining a molded article in which the composition is hardened.

[0059] 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 taking into consideration, for example, the type and content of the selected polymerization regulator, polymerization initiator, and / or other components. In cell cast polymerization, the heating temperature can be, for example, 50 to 130° C. The heating time can be, for example, 1 to 20 hours. The heat treatment can include a plurality of steps with different heating temperatures and / or heating times. The molded article by cell cast polymerization can be produced, for example, by carrying out a heat treatment under heating conditions including steps C1 to C7 described in the Examples below. This heat treatment can suppress heat generation during the polymerization reaction and allow the polymerization to be completed stably.

[0060] When the composition of the present disclosure is subjected to the above-mentioned 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.

[0061] 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.

[0062] The flat plate member may be 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.

[0063] 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.

[0064] 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.

[0065] The cured product and molded product of the present disclosure can be melt-kneaded after appropriate crushing treatment, etc., to recover the polymer (polymethyl methacrylate) (material recycling). For example, the melt-kneading conditions include kneading at a temperature at which the polymer (polymethyl methacrylate) melts. The polymer (polymethyl methacrylate), cured product, and molded product of the present disclosure can be thermally decomposed (depolymerized) to recover methyl (meth)acrylate (chemically recycled). The conditions for thermal decomposition are not particularly limited, and may be, for example, heating to 380 to 500°C.

[0066] <Applications of the polymer, cured product and molded product> The polymer (polymethyl methacrylate), cured product, and molded product obtained from the composition of the present disclosure 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

[0067] Hereinafter, embodiments of the present disclosure will be described based on examples, but the present disclosure is not limited to the following examples.

[0068] <Example 1> (Preparation of Composition) Composition 1 was prepared by adding 0.03 mass% of methyl pivalate (manufactured by Tokyo Chemical Industry Co., Ltd.) and 0.01 mass% of methyl isobutyrate (manufactured by Tokyo Chemical Industry Co., Ltd.) to 99.96 mass% of methyl methacrylate and mixing them at room temperature (25°C). The obtained composition 1 was liquid at room temperature and under 0.1 MPa (1 atm). The composition of composition 1 (content of methyl pivalate and methyl isobutyrate) is also shown in Table 1. Composition 1 corresponds to the composition of the present disclosure (not stored after preparation).

[0069] 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 a test to evaluate the stability after long-term storage, and was performed under accelerated conditions (60°C).

[0070] Step 1: 25 mL of the composition was poured into the bottom of a pressure vessel ("TVS-N2" manufactured by Taiatsu Glass Industries Co., Ltd.). Step 2: A gasket was placed between the top and bottom of the pressure vessel, sealing it. Step 3: Nitrogen was pumped into the top tip of the pressure vessel and sealed in at an internal pressure of 0.2 MPa. It was then confirmed that the internal pressure did not change for one minute. Step 4: The internal pressure in the pressure vessel was removed and a stopcock was installed 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 an oil bath for 24 hours. Step 7: After 24 hours, remove the pressure vessel from the oil bath and place it in ice-cold water to cool it down quickly.

[0071] Next, composition 1' (99.84 parts by mass), sodium di-(2-ethylhexyl)sulfosuccinate (0.05 parts by mass) as a release agent, terpinolene (0.013 parts by mass) as a polymerization regulator, and 2,2'-azobisisobutyronitrile (0.08 parts by mass) as a polymerization initiator were mixed at room temperature to obtain composition 1'' for forming a molded body (cast plate). The obtained composition 1'' was liquid at room temperature and under 0.1 MPa (1 atm). Composition 1' and Composition 1'' correspond to the compositions of the present disclosure (after storage test).

[0072] (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 was formed between the polyvinyl chloride resin gasket and the two glass plates. Composition 1'' was poured into the gap in the 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 C1 to C7 in this order, and a 3 mm thick, 100 mm square cast plate 1 was produced as a molded product of a cured product containing methyl methacrylate as a polymer. The following steps C1 to C7 were carried out in this order to suppress heat generation during the polymerization reaction and to stably complete the polymerization.

[0073] Step C1: The temperature was raised from room temperature to 68°C over 20 minutes. Step C2: 68°C was held for 90 minutes. Step C3: The temperature was lowered from 68°C to 64°C over 20 minutes. Step C4: 64°C was held for 90 minutes. Step C5: The temperature was increased from 64° C. to 123° C. over 10 minutes. Step C6: 123°C was held for 120 minutes. Step C7: The temperature was lowered from 123° C. to room temperature over 90 minutes.

[0074] (Measurement of 5% weight loss temperature) The cast plate 1 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 Corporation's "P / N SSC000E030 Open Sample Pan", diameter 5 mm). Using a thermogravimetric / differential thermal analyzer (Hitachi High-Tech Science Corporation's "TG / DTA7200"), the weight change of the crushed material was measured while heating 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. The higher the 5% weight loss temperature, the higher the thermal stability of the polymer. The results are shown in Table 1 and Figure 1.

[0075] <Examples 2 and 3, Comparative Example 1> In Example 1, the amount of methyl isobutyrate mixed was changed to the value shown in Table 1, and the amount of methyl methacrylate mixed was changed accordingly so that the total mixed amount was 100 mass% to prepare compositions 2, 3, and C1, and the compositions obtained were used to produce the compositions of Examples 2 and 3 and Comparative Example 1 (2', 2'', 3', 3'', C1', C1'') and cast plates 2, 3, and C1 in the same manner as in Example 1. The 5% weight loss temperatures of the cast plates 2, 3 and C1 were measured in the same manner as in Example 1. The results are shown in Table 1 and FIG.

[0076] [Table 1]

[0077] As is clear from the results shown in Table 1 and Figure 1, the composition of Comparative Example 1, which contains methyl methacrylate and a specified amount of methyl pivalate but does not contain methyl isobutyrate, has a low 5% weight loss temperature when molded under the above conditions. Therefore, it is clear that the composition of Comparative Example 1 is suitable for chemical recycling because it is susceptible to thermal decomposition, but cannot produce a molded product that exhibits sufficient thermal stability. In contrast, the compositions of Examples 1 to 3, which contain methyl pivalate and methyl isobutyrate in a predetermined content relative to methyl methacrylate, have a high 5% weight loss temperature when molded and excellent thermal stability even when stored under the above conditions, but are also capable of material recycling and chemical recycling by thermal decomposition. That is, the compositions of Examples 1 to 3 can achieve a characteristic of having both high thermal stability and excellent recyclability after use when molded into a molded product, and it is possible to control the thermal decomposition of the molded product. In addition, the compositions of Examples 1 to 3 are excellent in storage stability because the thermal decomposition of the molded product can be controlled even when stored under the above conditions. Furthermore, from the above results, it can be understood that when methyl pivalate and methyl isobutyrate are contained in a predetermined content in a composition containing methyl methacrylate, similar results can be obtained even when recycled methyl methacrylate or bio-derived methyl methacrylate is used as methyl methacrylate.

Claims

1. A composition comprising methyl methacrylate, methyl pivalate, and methyl isobutyrate, The content of the methyl methacrylate in the entire composition is 85% by mass or more, the content of the methyl pivalate in the entire composition is 100 ppm by mass or more and 600 ppm by mass or less, The content of the methyl isobutyrate in the entire composition is 50 ppm by mass or more and 2000 ppm by mass or less.

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

3. 2. The composition of claim 1, wherein the content of methyl isobutyrate is less than 2000 ppm by weight.

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

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

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

7. A molded body comprising the cured product described in claim 6.

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