Composition, cured product, and molded article

Abstract

To provide a composition capable of controlling thermal decomposability of molded articles, and polymers, cured products, and molded articles obtained using this composition, and a method for producing polymethyl methacrylate.SOLUTION: Provided is a composition containing methyl methacrylate, methyl pivalate, and methyl isobutyrate, wherein the concentration of methyl pivalate is more than 0 mass ppm and 50000 mass ppm or less in the composition, and the concentration of methyl isobutyrate is more than 0 mass ppm and 2000 mass ppm or less in the composition. Provided are a polymer, a cured product, and a molded article obtained by employing the composition, and a method for producing polymethyl methacrylate by polymerizing methyl methacrylate in the composition.SELECTED DRAWING: None

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, with the rise in resource prices and growing awareness of environmental issues, products (molded articles) containing polymethyl(meth)acrylate used for the various applications described above are being collected and recycled.

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

[0004] Furthermore, in response to the recent diversification of uses for polymethyl(meth)acrylate, techniques for improving the quality of polymethyl(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 vessel in which raw material monomers and a polymerization initiator react has been proposed (see Patent Document 1). [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Laid-Open No. 2012-102190 Summary of the Invention [Problem to be solved by the invention]

[0006] Incidentally, for molded articles intended for chemical recycling after use, the required quality level according to the intended use is becoming higher. On the other hand, if the thermal stability, among other qualities, of the molded article is made too high, the suitability for recycling processing will be poor. Therefore, when it comes to the quality of molded articles containing polymethyl(meth)acrylate, it is important to consider the required level according to the intended use and the suitability for recycling processing, and to strike a good balance between these. As an indicator of such quality, the thermal decomposition rate 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 using the composition, and 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 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 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 the preceding claims. <5> The methyl methacrylate comprises recycled methyl methacrylate or bio-derived methyl methacrylate; <1> ~ <4> The composition according to any one of the preceding claims. <6> Further containing the (meth)acrylic acid ester other than methyl methacrylate, <1> ~ <5> The composition according to any one of the preceding claims. <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 4. <8> the above <7> A molded article comprising the polymer described in 1. <9> the above <1> ~ <6> A cured product of the composition according to any one of claims 1 to 4. <10> the above <9> A molded article comprising the cured product according to claim 1. <11> the above <1> ~ <6> 10. A method for producing polymethyl methacrylate, comprising the step of polymerizing the methyl methacrylate contained in the composition according to any one of claims 1 to 9. [Effects 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 using the composition, and a method for producing polymethyl methacrylate using the composition, for example. [Brief explanation 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 INVENTION

[0011] Hereinafter, one embodiment of the present disclosure will be described, but 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." Furthermore, in this disclosure and this specification, when describing content, physical properties, etc., by indicating a numerical range, if the upper and lower limits of the numerical range are described separately, any of the upper and lower limits can be appropriately combined to form a specific numerical range. On the other hand, when describing multiple numerical ranges expressed using "to", the upper and lower limits forming the numerical range are not limited to the specific combination written before and after "to" as a specific numerical range, but can be a numerical range obtained by appropriately combining the upper and lower limits of each numerical range. Note that in this disclosure and this specification, a numerical range expressed using "to" means a range that includes the numerical values ​​written before and after "to" as the upper and lower limits.

[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 below, by incorporating methyl pivalate and methyl isobutyrate into a composition containing methyl methacrylate and then setting the contents of methyl pivalate and methyl isobutyrate within the above-mentioned specific ranges, the 5% weight loss temperature of a molded article formed using the composition can be improved while maintaining the glass transition temperature of the molded article (polymer, specifically, a homopolymer or copolymer of methyl methacrylate). As a result, the composition of the present disclosure is resistant to thermal decomposition, and when formed into a molded article, it can impart the desired thermal stability and improve heat resistance. Meanwhile, the polymethyl methacrylate contained in a molded article formed using the composition of the present disclosure maintains its thermal decomposition property even when its thermal stability is increased. Therefore, when formed into a molded article, the composition of the present disclosure can achieve both high thermal stability and excellent recyclability after use, and the thermal decomposition property of the molded article can be controlled.

[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 also be used as a mixture with methyl pivalate, methyl isobutyrate, other components (especially low-content components) described below, solvents, etc., in addition to the inevitable impurities, as long as the purpose of the present disclosure is not impaired and the composition, cured product, or molded article of the present disclosure (components and contents) is satisfied.

[0015] The content of methyl methacrylate in the composition (of the entire composition) is not particularly limited and can be determined appropriately depending on the use of polymethyl methacrylate obtained using the composition, etc. The content of methyl methacrylate is not particularly limited, but is, for example, 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 also be 95% by mass or more or 99% by mass or more, in order to maintain the excellent properties of polymethyl methacrylate, its molded articles, etc.

[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 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 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 the raw material for recycled 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 product 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 biologically derived raw material. The biologically derived raw material may be a plant-derived raw material or an animal-derived raw material, but is preferably a raw material derived from vegetable oil.

[0019] The methyl methacrylate contained in the composition of the present disclosure may include at least one of synthetic methyl methacrylate, recycled methyl methacrylate, and bio-derived methyl methacrylate. From the perspective of addressing the above-mentioned rising resource prices and environmental issues, the composition of the present disclosure preferably includes at least one of recycled methyl methacrylate and bio-derived methyl methacrylate as the methyl methacrylate. Note that, in the present disclosure, the content of each of synthetic methyl methacrylate, recycled methyl methacrylate, and bio-derived methyl methacrylate relative to the total mass of methyl methacrylate contained in the composition of the present disclosure is not particularly limited and can be determined as appropriate.

[0020] (Methyl pivalate) The composition of the present disclosure contains methyl pivalate. The content of methyl pivalate in the entire composition is greater than 0 ppm by mass and not more than 50,000 ppm by mass, relative to 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, at predetermined contents relative to methyl methacrylate can improve the storage stability of the composition or the thermal stability of the 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 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 greater than 0 ppm by mass and 2000 ppm by mass or less, relative to 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 the thermal stability of the 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 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.

[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 thermal decomposition (enhancing thermal stability), the upper limit can be set to less than 2000 ppm by mass relative to the total mass of the composition. Taking into consideration the thermal decomposition of the molded body, the upper limit 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 other components include (meth)acrylic acid 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 one that is (intentionally) mixed separately from the above-mentioned methyl methacrylate, etc., but it may also be a by-product produced 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 determined appropriately. For example, the upper limit of the (meth)acrylic acid ester content 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, based on the total composition. On the other hand, the lower limit of the (meth)acrylic acid ester content can be 1 ppm by mass or more, or may be 2 ppm by mass or more, or 5 ppm by mass or more, based on the total composition.

[0029] (low content ingredients) The compositions of the present disclosure may contain minor components other than methyl pivalate and methyl isobutyrate, which may be present in the composition as by-products produced during the production of methyl methacrylate or during the recycling process of polymethyl methacrylate. In the present disclosure, a low content component refers to a component contained in a composition in an amount of 10,000 ppm by mass or less, provided that the above (meth)acrylic acid esters and the additives described below are not included in the low content component even if their respective contents in the composition are 10,000 ppm by mass or less.

[0030] Examples of low content components include carboxylic acid ester 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 carboxylic acid ester 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 alcohol compounds 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 determined appropriately.For example, the upper limit of the content of each compound group is preferably 8000 mass ppm or less, more preferably 6000 mass ppm or less, and even more preferably 5000 mass ppm or less of the total composition.On the other hand, the lower limit of the content of each compound group can be 1 mass ppm or more, 2 mass ppm or more, or 5 mass ppm or more of the total composition.

[0033] (additives) The composition of the present disclosure may contain additives as needed. The additives are not particularly limited, and examples thereof include a mold 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 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 one type or two or more types. The content of the release agent is not particularly limited and can be determined appropriately, for example, to be 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 slowing down 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 composition of the present disclosure may contain one or more types of polymerization regulator. The content of the polymerization regulator is not particularly limited and can be determined appropriately, for example, to be 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 peroxyester initiator, a percarbonate initiator, and a peroxyketal 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 tert-butylperoxyallyl carbonate and tert-butylperoxyisopropyl carbonate.

[0041] 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.

[0042] The composition of the present disclosure may contain one type of polymerization initiator or two or more types of polymerization initiators. The content of the polymerization initiator is not particularly limited and can be determined appropriately, for example, to be 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 absorbers. The content of the ultraviolet absorber is not particularly limited and can be determined appropriately, for example, to be 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 additives, their total content is not particularly limited and can be determined appropriately. The upper limit of the total content of the additives can be, for example, 15% by mass or less of the total composition, but can also be appropriately set 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 the additives can be, for example, 0.01% by mass or more of the total composition, but can also be appropriately set 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 typically be prepared by mixing methyl methacrylate, methyl pivalate, methyl isobutyrate, and other components as appropriate in the proportions that result in the above-mentioned respective contents. The mixing method is not particularly limited, and the components may be mixed all at once or sequentially. When mixed sequentially, the order of mixing is not particularly limited. Furthermore, the mixing conditions are not particularly limited and can be determined as appropriate, but it is preferable to select conditions that suppress the evaporation 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. to be mixed is determined taking into consideration the content in the mixture with methyl methacrylate used. Note that, when the content of methyl pivalate, etc. 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. Because the composition of the present disclosure exhibits excellent storage stability, one preferred embodiment is to store the composition after preparation and then use it. The storage conditions for storing the composition of the present disclosure are not particularly limited, but the storage temperature can be, for example, 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 from the range of approximately 25°C ± 10°C, and even more preferably from the range of approximately 25 to 30°C. The storage time can be determined appropriately 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 structural units derived from methyl methacrylate contained in the composition of the present disclosure described above. Here, the polymer is obtained by polymerizing components involved in polymerization contained in the composition, and has structural units derived from the components involved in polymerization. The polymer of the present disclosure may contain structural units derived from methyl methacrylate contained in the composition of the present disclosure and structural units derived from other polymerization components. Examples of 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 depending on 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 product obtained by curing a composition and may contain components that are not involved in polymerization. However, depending on the method for curing the composition and the composition of the composition, it may be considered 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 any method that is normally applied to compositions, and includes polymerization methods and crosslinking methods, with polymerization methods being preferred. 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 produced by the method for producing a cured product described below.

[0050] The molded article of the present disclosure includes the polymer or cured product of the present disclosure described above. If the cured product can be considered the same as the polymer, the molded article of the present disclosure will include a 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 dimensions suitable for the intended use using various known molding methods. Examples of shapes include sheet-like shapes (including film-like, strip-like, and plate-like shapes, which may be long or short (leaf-like)), block-like shapes, and various three-dimensional shapes. The molded article of the present disclosure is manufactured by the molded article manufacturing method described below.

[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 of the composition, the molding conditions, etc. In one embodiment, the cured product or molded article of the present disclosure may contain (remain) residual (unpolymerized) methyl methacrylate, methyl pivalate, methyl isobutyrate, and other components. In another embodiment of the molded article of the present disclosure, it is preferable that the residual components are removed to an extent that satisfies the required properties for the intended use.

[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 50,000 ppm by mass or less, relative to the total mass (100 parts by mass) of the cured product or molded product. From the viewpoint of controlling the thermal decomposition property of the molded product, for example, from the viewpoint of increasing the thermal decomposition property of the cured product or molded product, the content of methyl pivalate is, for example, 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 cured product or molded product. 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, 2,000 ppm by mass or less, preferably 1,000 ppm by mass or less, and more preferably 600 ppm by mass or less, relative to the total mass of the cured product or molded product.

[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, relative to the total mass (100 parts by mass) of the cured product or molded product. From the viewpoint of controlling the thermal decomposition property of the molded product, for example, from the viewpoint of increasing the thermal decomposition property of the cured product or molded product, the content of methyl isobutyrate is, for example, 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 cured product or molded product. 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, 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, relative to the total mass of the cured product or molded product.

[0054] When the cured product or molded article of the present disclosure contains the other components described above, the content of each component is not particularly limited and can be set, for example, within 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 polymers, cured products, and molded articles> 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 methyl methacrylate contained in the composition of the present disclosure is not particularly limited, and examples thereof include 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 methyl methacrylate contained in the composition of the present disclosure. The method for producing a polymer according to the present disclosure is not limited to a method in which methyl pivalate and methyl isobutyrate are present in a predetermined content (mixing amount) when polymerizing methyl methacrylate, and is not limited to a method in which the above-mentioned polymerization step is carried out using a pre-prepared composition according to the present disclosure. For example, the method for producing a polymer according to the present disclosure includes a method in which, without pre-preparing the composition according to the present disclosure, methyl pivalate and methyl isobutyrate are mixed in a predetermined mixing amount with methyl methacrylate to form a polymerization system corresponding to the composition according to the present disclosure, and then methyl methacrylate is polymerized. Therefore, in this disclosure and this specification, when referring to a polymer obtained using a composition according to the present disclosure or a polymer formed using a composition according to the present disclosure, as described above, it includes polymers obtained in at least two embodiments: an embodiment in which a composition according to the present disclosure is used, and an embodiment in which a composition according to the present disclosure is formed in a polymerization system. This also applies to the cured products and molded articles described below.

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

[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 heat-treated under predetermined heating conditions to allow the polymerization reaction to proceed, thereby obtaining a molded article in which the composition is cured.

[0059] In the method for polymerizing methyl methacrylate contained in the composition of the present disclosure or the method for producing a molded article, the heating conditions, such as the heating temperature and heating time, 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 be a heat treatment including multiple steps with different heating temperatures and / or heating times. The molded article obtained by cell-cast polymerization can be produced by, for example, performing a heat treatment under heating conditions including steps C1 to C7 described in the Examples below. This heat treatment suppresses heat generation during the polymerization reaction, allowing the polymerization to be completed stably.

[0060] When the composition of the present disclosure is subjected to the heat treatment, for example, a cell casting method (cell cast polymerization) using a cell capable of defining an enclosed space of a predetermined shape inside can be applied to form a molded article of a predetermined shape. The method for producing a molded article 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 in the form of a plate (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 sandwiched between the two flat plate-like members and can seal the gap between the two opposing flat plate-like members as an airtight space.

[0062] The flat plate-like member may be in the form of a sheet or a belt. The flat plate-like 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-like member include glass and metal.

[0063] Any suitable conventional sealing material can be used as the sealing material. The sealing material is composed 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 cells by any suitable conventional method. The cells are then heat-treated under the heating conditions already described. The method of heat-treating the cells into which the composition of the present disclosure has been injected is not particularly limited. The heat-treating method for the cells may be, as in the conventionally known cell casting method, a method in which the cells are directly heat-treated from the outside using a hot air circulating oven, an infrared heater, or the like, or a method in which a conventionally known jacket is further provided on the outside of the cells and a heat medium such as hot air, hot water, or steam is introduced into the jacket.

[0065] The cured product and molded article of the present disclosure can be melt-kneaded after appropriate crushing or other treatment, and the polymer (polymethyl methacrylate) can be recovered (material recycling). Examples of conditions for melt-kneading include kneading at a temperature at which the polymer (polymethyl methacrylate) melts. The polymer (polymethyl methacrylate), cured product, and molded article 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 examples include heating to 380 to 500°C.

[0066] <Applications of polymers, cured products, and molded products> The polymer (polymethyl methacrylate), cured product, and molded article obtained from the composition of the present disclosure each have excellent light transmittance, heat resistance, and weather resistance, making them suitable for a variety of applications that may be exposed to the external environment and even heat and light sources, such as lighting fixtures, automobile parts, signs, and building materials. [Example]

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

[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 stability after long-term storage, and was carried out under accelerated conditions (60°C).

[0070] Step 1: 25 mL of the composition was poured into the bottom of a pressure vessel ("TVS-N2 type" manufactured by Taiatsu Glass Industry 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 pressure vessel from the top tip, and the vessel was sealed with 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 released and a stopcock was attached to the tip of the top of the pressure vessel. Step 5: The pressure vessel was placed in an oil bath set at 60°C. Step 6: Store in an oil bath for 24 hours. Step 7: After 24 hours, the pressure vessel was removed from the oil bath and placed in ice-cold water to rapidly cool it down.

[0071] Next, Composition 1' (99.84 parts by mass), sodium di-(2-ethylhexyl)sulfosuccinate (0.05 parts by mass) as a mold 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 resulting 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] (Cast plate production) A cell was prepared in which a 3.8 mm thick vinyl chloride resin gasket was sandwiched between two opposing glass plates, forming a sealed gap between the vinyl chloride resin gasket and the two glass plates. Composition 1″ was poured into the gap within this cell. The cell containing Composition 1″ was placed in an oven, and heat treatment was carried out under heating conditions including the following steps C1 to C7, in this order, to polymerize Composition 1″. A 3 mm thick, 100 mm square cast plate 1 was produced as a molded product of a cured product containing methyl methacrylate as the polymer. Steps C1 to C7, in this order, were carried out to suppress heat generation during the polymerization reaction and ensure stable completion of 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) Cast plate 1 was crushed to a diameter or side length 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, P / N SSC000E030 Open Sample Pan, 5 mm diameter). The weight change of the crushed material was measured using a thermogravimetric / differential thermal analyzer (Hitachi High-Tech Science Corporation, TG / DTA7200) at a nitrogen gas flow rate of 200 mL / min and a heating rate of 10 °C / min from 45 °C to 520 °C. The weight of the crushed material decreased with increasing temperature. The weight of the crushed material at the initial temperature (45 °C) was defined as 100 wt %, and the temperature at which the weight of the crushed material decreased by 95 wt % (5% weight loss temperature) was calculated. A higher 5% weight loss temperature indicates a higher 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% by mass to prepare compositions 2, 3, and C1, and the compositions of Examples 2, 3, and Comparative Example 1 (2', 2'', 3', 3'', C1', C1'') and cast plates 2, 3, and C1 were produced in the same manner as Example 1, except that the resulting compositions were used. 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, exhibits a low 5% weight loss temperature when molded under the above conditions. Therefore, it is clear that the composition of Comparative Example 1 is susceptible to thermal decomposition and is therefore suitable for chemical recycling, but it is not possible to produce molded products that exhibit sufficient thermal stability. In contrast, the compositions of Examples 1 to 3, which contain a predetermined amount of methyl pivalate and methyl isobutyrate relative to methyl methacrylate, exhibit a high 5% weight loss temperature when molded into a molded product, providing excellent thermal stability, even when stored under the above conditions. These compositions also enable material recycling and chemical recycling via thermal decomposition. That is, the compositions of Examples 1 to 3 can achieve both high thermal stability and excellent recyclability after use when molded into a molded product, making it possible to control the thermal decomposition of the molded product. Furthermore, the compositions of Examples 1 to 3 also exhibit excellent storage stability, since the thermal decomposition of the molded product can be controlled even when stored under the above conditions. Furthermore, the above results demonstrate that when a composition containing methyl methacrylate contains a predetermined amount of methyl pivalate and methyl isobutyrate, similar results can be obtained even when recycled methyl methacrylate or bio-derived methyl methacrylate is used as the methyl methacrylate.

Claims

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, The 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 composition according to claim 1, wherein the content of the methyl methacrylate in the entire composition is 85 mass% or more.

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

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

5. 10. The composition of claim 1, wherein the methyl methacrylate comprises recycled methyl methacrylate or bio-sourced methyl methacrylate.

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

7. A polymer comprising structural units derived from the methyl methacrylate contained in the composition according to any one of claims 1 to 6.

8. A molded article comprising the polymer according to claim 7.

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

10. A molded article comprising the cured product according to claim 9.

11. A method for producing polymethyl methacrylate, comprising a step of polymerizing the methyl methacrylate contained in the composition according to any one of claims 1 to 6.

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