Method for producing methyl methacrylate, composition, polymer, cured product, and molded product

Abstract

To provide a method for producing methyl methacrylate in which odor is suppressed, a composition, a polymer, a cured product, and a molded body.SOLUTION: The present invention relates to a method for producing methyl methacrylate, the method including a step of bringing a composition containing methyl methacrylate and an odor component into contact with an adsorbent.SELECTED DRAWING: None

Description

[Technical Field]

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

[0002] Polymethyl(meth)acrylate obtained by polymerizing methyl(meth)acrylate is used in various fields as a resin material with excellent transparency and weather resistance. In recent years, 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 the recovered methyl(meth)acrylate (sometimes referred to as recycled MMA or recycled MA) is used to produce new molded bodies; and thermal recycling, in which 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] For example, Patent Document 1 describes a method for recovering methyl (meth)acrylate through a process in which a gaseous pyrolysis product obtained by heating polymethyl (meth)acrylate is cooled and liquefied, and the liquefied pyrolysis product is then purified by distillation. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Laid-Open No. 2003-321571 Summary of the Invention [Problem to be solved by the invention]

[0006] Methyl (meth)acrylate, which is used as a raw material for polymethyl (meth)acrylate, can emit an unpleasant odor. Therefore, it is desirable to suppress the odor of methyl (meth)acrylate in order to improve its handling. In view of the above circumstances, an object of the present disclosure is to provide a method for producing methyl methacrylate, a composition, a polymer, a cured product, and a molded article that suppress odor. [Means for solving the problem]

[0007] Means for solving the above problems include the following embodiments. <1> A method for producing methyl methacrylate, comprising a step of contacting a composition containing methyl methacrylate and odorous components with an adsorbent. <2> The amount of the adsorbent to be contacted with the composition is 1 part by mass to 30 parts by mass per 100 parts by mass of the composition. <1> The method for producing methyl methacrylate according to claim 1. <3> The concentration of odorous components in the composition after the step of contacting the composition with the adsorbent is less than 450 ppm by mass with respect to the entire composition. <1> or <2> The method for producing methyl methacrylate according to claim 1. <4> The odorous components include at least one selected from the group consisting of alcohols, aldehydes, ketones, fatty acids, sulfur-containing compounds, and nitrogen-containing compounds. <1> ~ <3> of The method for producing methyl methacrylate according to any one of claims 1 to 14. <5> The adsorbent comprises zeolite or activated carbon; <1> ~ <4> The method for producing methyl methacrylate according to any one of the above. <6> The adsorbent comprises a zeolite containing silver ions; <5> The method for producing methyl methacrylate according to claim 1. <7> The adsorbent is in the form of beads, and the particle diameter is 1 mm to 7 mm. <1> ~ <6> The method for producing methyl methacrylate according to any one of the above. <8> The method further comprises a step of recovering methyl methacrylate contained in the composition from a pyrolysis product of polymethyl methacrylate before the step of contacting the composition with the adsorbent. <1> ~ <7> The method for producing methyl methacrylate according to any one of the above. <9> Contains methyl methacrylate and odorous components, A composition having an odorous component concentration of more than 0 ppm by mass and less than 450 ppm by mass of the entire composition. <10> The content of methyl methacrylate in the entire composition is 85% by mass or more. <9> The composition described in <11> The content of methyl methacrylate in the entire composition is 90% by mass or more. <9> or <10> The composition described in <12> The odor components include at least one selected from the group consisting of alcohols, aldehydes, ketones, fatty acids, sulfur-containing compounds, and nitrogen-containing compounds. <9> ~ <11> The composition according to any one of the preceding claims. <13> The odor components include at least sulfur-containing compounds or nitrogen-containing compounds. <12> The composition described in <14> The methyl methacrylate comprises recycled methyl methacrylate or bio-derived methyl methacrylate; <9> ~ <13> The composition according to any one of the preceding claims. <15> Further containing (meth)acrylic acid esters other than methyl methacrylate, <9> ~ <14> The composition according to any one of the preceding claims. <16> Further comprising a polymer containing structural units derived from methyl methacrylate, <9> ~ <15> The composition according to any one of the preceding claims. <17> <9> ~ <16> A polymer comprising a structural unit derived from methyl methacrylate contained in the composition according to any one of claims 1 to 4. <18> <17> A molded article comprising the polymer described in 1. <19> <9> ~ <16> A cured product of the composition according to any one of claims 1 to 4. <20> <19> A molded article comprising the cured product according to claim 1. [Effects of the Invention]

[0008] According to the present disclosure, there are provided a method for producing odor-suppressed methyl methacrylate, a composition, a polymer, a cured product, and a molded article. DETAILED DESCRIPTION OF THE INVENTION

[0009] Hereinafter, embodiments of the present invention will be described, but the present invention is not limited to the following embodiments. In this specification, numerical ranges indicated using "to" include the numerical values ​​before and after "to" as the minimum and maximum values, respectively. In the present specification, the upper or lower limit of one numerical range may be replaced with the upper or lower limit of another numerical range. In addition, in the present specification, the upper or lower limit of a numerical range may be replaced with a value shown in the examples.

[0010] <Method for producing methyl methacrylate> One embodiment of the present disclosure is a composition containing methyl methacrylate and an odor component, and an adsorbent and a step of contacting the above-mentioned methyl methacrylate with each other.

[0011] As will be shown in the examples below, bringing an adsorbent into contact with a composition containing methyl methacrylate and an odorous component is effective in suppressing the odor of methyl methacrylate. Furthermore, since the method of the present disclosure uses an adsorbent as a means for suppressing odor, it can be carried out more easily and at lower cost than methods such as distillation.

[0012] The type of adsorbent to be brought into contact with the composition is not particularly limited, and can be selected depending on the type, concentration, etc. of odorous components contained in the composition. From the viewpoint of the odor suppression effect and ease of handling of the adsorbent, the adsorbent preferably contains zeolite or activated carbon, more preferably contains zeolite, and even more preferably contains zeolite containing silver ions. The adsorbent to be brought into contact with the composition may be one kind or two or more kinds.

[0013] From the viewpoint of the odor suppression effect and ease of handling of the adsorbent, the adsorbent is preferably in the form of pellets, beads, or powder, and more preferably in the form of beads. The particle diameter of the adsorbent may be, for example, 10 mm or less, preferably 1 mm to 7 mm, and more preferably 6 mm or less. The adsorbent is more preferably in the form of beads with a particle diameter of 1 mm to 7 mm.

[0014] The amount of adsorbent to be brought into contact with the composition is not particularly limited, and can be selected depending on the type and concentration of odorous components contained in the composition. From the viewpoint of fully exerting the odor suppression effect of the adsorbent, the amount of adsorbent brought into contact with the composition is preferably 1 part by mass or more, more preferably 2 parts by mass or more, and even more preferably 5 parts by mass or more, per 100 parts by mass of the composition. From the viewpoint of efficiency and economy of the operation after contacting the adsorbent with the composition (for example, the operation of removing the adsorbent from the composition), the amount of adsorbent brought into contact with the composition is preferably 30 parts by mass or less, more preferably 20 parts by mass or less, and even more preferably 15 parts by mass or less, per 100 parts by mass of the composition.

[0015] After the step of contacting the composition with the adsorbent, the adsorbent may be removed from the composition. The time for contacting the composition with the adsorbent (the time from the start of contact to the time the adsorbent is removed) is not particularly limited and can be selected depending on the type, concentration, etc. of odorous components contained in the composition. The time for which the adsorbent is in contact with another adsorbent can be adjusted within a range that provides the desired odor suppression effect, and can be selected, for example, from 1 hour to 1 week. The time for which the adsorbent is in contact with another adsorbent can be, for example, 3 hours, 6 hours, or 24 hours, or can be any other time.

[0016] The concentration of odorous components in the composition after the step of contacting the composition with the adsorbent is preferably less than 450 mass ppm relative to the entire composition. When the concentration of odorous components is less than 450 mass ppm relative to the entire composition, the degree of discomfort felt by those handling the composition is effectively reduced. The concentration of odorous components in the composition after the step of contacting the composition with the adsorbent may be 300 ppm by mass or less, 250 ppm by mass or less, 200 ppm by mass or less, 150 ppm by mass or less, 100 ppm by mass or less, 90 ppm by mass or less, 50 ppm by mass or less, or 25 ppm by mass or less, based on the entire composition. The concentration of the odorous component in the composition after the step of contacting the composition with the adsorbent is preferably as low as possible. The concentration of the odorous component may be, for example, 0 ppm by mass, more than 0 ppm by mass, 2 ppm by mass or more, 5 ppm by mass or more, or 10 ppm by mass or more relative to the entire composition. When the composition contains two or more odorous components, the concentrations of the odorous components mentioned above are the concentrations of each odorous component.

[0017] The type of odorous component contained in the composition is not particularly limited. The odorous component may include at least one selected from the group consisting of alcohols, aldehydes, ketones, fatty acids, sulfur-containing compounds, and nitrogen-containing compounds. In some embodiments, the composition may include a sulfur-containing compound or a mercaptan compound as an odorant component. In some embodiments, the composition may include a nitrogen-containing compound or an amine compound as an odor component. The odor component contained in the composition may be one kind or two or more kinds.

[0018] The method of the present disclosure may include a step of recovering methyl methacrylate contained in the composition from a pyrolysis product of polymethyl methacrylate prior to the step of contacting the composition with an adsorbent. Methyl methacrylate recovered from the pyrolysis product of polymethyl methacrylate may contain substances that are inevitably mixed into the recovered polymethyl methacrylate and may cause odor. For example, mercaptan compounds such as n-butyl mercaptan, n-octyl mercaptan, and n-dodecyl mercaptan, which are added to the composition as polymerization regulators, may be contained in polymethyl methacrylate as odorous components. The method for carrying out the step of recovering methyl methacrylate from the pyrolysis product of polymethyl methacrylate is not particularly limited, and can be selected from known methods. In one embodiment, the step of recovering methyl methacrylate from a pyrolysate of polymethyl methacrylate may include the steps of heating polymethyl(meth)acrylate to obtain a gaseous pyrolysate, cooling the gaseous pyrolysate to liquefy it, and purifying the liquefied pyrolysate by distillation.

[0019] The method of the present disclosure may include a step of removing substances other than methyl methacrylate and odorous components contained in the composition. Substances other than methyl methacrylate and odorous components include additives contained in polymethyl methacrylate recovered for recycling, and other materials recovered together with polymethyl methacrylate. The method for carrying out the step of removing substances other than methyl methacrylate and odorous components contained in the composition is not particularly limited, and can be selected from known methods. The step of removing substances other than methyl methacrylate and odorous components contained in the composition may be carried out before or after the step of contacting the composition with an adsorbent. The method for removing substances other than methyl methacrylate and odorous components contained in the composition is not particularly limited, and can be selected from known purification techniques.

[0020] In the method of the present disclosure, the composition with which the adsorbent is brought into contact is not particularly limited as long as it contains methyl methacrylate and an odorous component. For details and preferred embodiments of the composition with which the adsorbent is contacted, please refer to the details and preferred embodiments of the composition of the present disclosure described below.

[0021] <Composition> One embodiment of the present disclosure comprises methyl methacrylate and an odor component, The composition has an odorous component concentration of more than 0 ppm by mass and less than 450 ppm by mass of the entire composition.

[0022] Even if the composition of the present disclosure contains an odorous component together with methyl methacrylate, the degree to which the composition causes discomfort to those who handle the composition is low.

[0023] The concentration of the odorous components in the composition is not particularly limited as long as it is less than 450 ppm by mass relative to the entire composition. The concentration of the odorous components may be 300 ppm by mass or less, 250 ppm by mass or less, 200 ppm by mass or less, 150 ppm by mass or less, 100 ppm by mass or less, 90 ppm by mass or less, 50 ppm by mass or less, or 25 ppm by mass or less relative to the entire composition. The concentration of the odorous component in the composition is preferably as low as possible. The concentration of the odorous component may be, for example, 0 ppm by mass, more than 0 ppm by mass, 2 ppm by mass or more, 5 ppm by mass or more, or 10 ppm by mass or more relative to the entire composition. When the composition contains two or more odorous components, the concentrations of the odorous components mentioned above are the concentrations of each odorous component.

[0024] The type of odorous component contained in the composition is not particularly limited. The odorous component may include at least one selected from the group consisting of alcohols, aldehydes, ketones, fatty acids, sulfur-containing compounds, and nitrogen-containing compounds. In some embodiments, the composition may include a sulfur-containing compound or a mercaptan compound as an odorant component. In some embodiments, the composition may include a nitrogen-containing compound or an amine compound as an odor component. The odor component contained in the composition may be one kind or two or more kinds.

[0025] (methyl methacrylate) In the method of the present disclosure, the composition contacting the adsorbent comprises methyl methacrylate. In this disclosure, "methyl methacrylate" refers to methyl methacrylate that is essentially free of impurities such as by-products generated during the synthesis of methyl methacrylate. However, the methyl methacrylate in this disclosure is not limited to this, provided that the purpose of the invention is not impaired. In other words, "methyl methacrylate" may contain impurities that cannot be completely removed by conventional purification methods, or may contain impurities at a level that cannot be detected by conventional detection methods.

[0026] The content of methyl methacrylate in the composition is not particularly limited and can be selected depending on the application of polymethyl methacrylate obtained using the composition, etc. The content of methyl methacrylate may be, for example, 85% by mass or more, 90% by mass or more, 95% by mass or more, or 99% by mass or more of the total composition. When the content of methyl methacrylate in the composition is within the above range, it is preferable from the viewpoint of at least heat resistance or transparency (light transmittance) of a polymer obtained by polymerizing the composition and a molded article containing the same.

[0027] The methyl methacrylate contained in the composition may be synthesized by a known synthesis method, which is not particularly limited and may be the ACH method, the C4 direct oxidation method, or the alpha method.

[0028] 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). Depolymerization of polymethyl methacrylate can be effected, for example, by subjecting polymethyl methacrylate to heat treatment. The source of polymethyl methacrylate, which is the raw material for recycled methyl methacrylate, is not particularly limited as long as methyl methacrylate can be recovered. For example, The source may be a molded body comprising polymethyl methacrylate.

[0029] The methyl methacrylate included in the composition may include bio-derived methyl methacrylate. In the present disclosure, bio-derived methyl methacrylate refers to 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, and preferably is a raw material derived from vegetable oil.

[0030] If necessary, the composition may contain components other than methyl methacrylate and odorous components. For example, the composition may contain (meth)acrylic acid esters other than methyl methacrylate, polymers containing structural units derived from methyl methacrylate, low-content components, or additives, as described below.

[0031] ((Meth)acrylic acid ester) The composition may contain, in addition to methyl methacrylate, a (meth)acrylic acid ester other than methyl methacrylate (hereinafter also simply referred to as a (meth)acrylic acid ester). Specific examples of (meth)acrylic acid esters include methyl acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, n-butyl (meth)acrylate, sec-butyl (meth)acrylate, tert-butyl (meth)acrylate, cyclohexyl (meth)acrylate, benzyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, 2-hydroxyethyl (meth)acrylate, and cyclopentanyl (meth)acrylate. Among these, methyl acrylate or ethyl acrylate is preferred, and methyl acrylate is more preferred. These may be used alone or in combination of two or more. In the present disclosure, the term "(meth)acrylic acid ester" indicates that it may be either an acrylic acid ester or a methacrylic acid ester. The (meth)acrylic acid ester may be contained in the composition as a by-product produced during the production of methyl methacrylate or during the regeneration treatment of polymethyl methacrylate, or may be intentionally mixed into the composition.

[0032] When the composition contains a (meth)acrylic acid ester, the concentration thereof is preferably 50,000 ppm by mass or less, more preferably 40,000 ppm by mass or less, and even more preferably 30,000 ppm by mass or less, of the entire composition. When the composition contains a (meth)acrylic acid ester, the concentration thereof may be 1 ppm by mass or more, 2 ppm by mass or more, or 5 ppm by mass or more of the total composition.

[0033] The composition may contain, in addition to methyl methacrylate, a polymer containing structural units derived from methyl methacrylate. This polymer may be a homopolymer of methyl methacrylate or a copolymer of methyl methacrylate with another (meth)acrylic acid ester polymerizable with methyl methacrylate. Examples of other (meth)acrylic acid esters polymerizable with methyl methacrylate include the same as those described above.

[0034] (low content ingredients) The composition may contain minor components other than odorous components. The minor components may be contained 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 means a component that is contained in the composition at a concentration of 10,000 ppm by mass or less.

[0035] Minor components that the composition may contain include carboxylic acid esters, aromatic hydrocarbon compounds, aliphatic hydrocarbon compounds, alcohols, butyl acrylate, and the like. The composition may contain only one low content component or two or more low content components.

[0036] Specific examples of carboxylic acid esters include methyl isobutyrate, methyl propionate, methyl 2,4-dimethyl-4-pentenoate, methyl 2-methyl-3-butenoate, methyl tiglate, methyl 3-methyl-3-butenoate, methyl 3-methyl-2-butenoate, dimethyl itaconate, and dimethyl 2-methyl-5-methylenehexanedioate. Specific examples of aromatic hydrocarbon compounds include toluene and styrene. Specific examples of the aliphatic hydrocarbon compound include 1-octene and 1-octadecene.

[0037] When the composition contains low content components other than odorous components, the concentration of each low content component is preferably 8000 ppm by mass or less, more preferably 6000 ppm by mass or less, and even more preferably 5000 ppm by mass or less of the total composition. When the composition contains low content components other than odorous components, the concentration of each low content component may be 1 ppm by mass or more, 2 ppm by mass or more, or 5 ppm by mass or more of the total composition.

[0038] (additives) If necessary, the composition may contain additives, such as a mold release agent, a polymerization regulator, a polymerization initiator, an ultraviolet absorber, and a colorant. The composition may contain one or more additives.

[0039] Examples of release agents that the composition may contain include higher fatty acid esters, higher fatty alcohols, higher fatty acids, higher fatty acid amides, higher fatty acid metal salts, and fatty acid derivatives. Specific examples of mold release agents include sodium di-(2-ethylhexyl) sulfosuccinate, stearyl alcohol, methyl stearate, and stearic acid amide.

[0040] The composition may contain one or more types of release agents. The content of the release agent in the composition can be, for example, 0.01% by mass to 1.0% by mass of the entire composition.

[0041] The polymerization regulator (an additive that regulates the polymerization rate in a polymerization reaction) that may be contained in the composition may be any suitable polymerization regulator known in the art. Examples of such polymerization regulators include compounds that can regulate the polymerization rate in a direction that decreases the polymerization rate. Specific examples of the polymerization regulator include mercaptan compounds such as n-butyl mercaptan, n-octyl mercaptan, and n-dodecyl mercaptan; terpenoid compounds such as limonene, myrcene, α-terpinene, β-terpinene, γ-terpinene, terpinolene, β-pinene, and α-pinene; and α-methylstyrene dimer.

[0042] The composition may contain one or more types of polymerization regulators. The content of the polymerization regulator in the composition can be, for example, 0.001% by mass to 0.5% by mass of the total composition.

[0043] The polymerization initiator that the composition may contain includes a radical polymerization initiator, a diacyl peroxide initiator, a dialkyl peroxide initiator, a peroxyester initiator, a percarbonate initiator, and a peroxyketal initiator.

[0044] Specific examples of radical polymerization initiators include 1,1'-azobis(cyclohexane-1-carboxylate). Examples of azo compounds include 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).

[0045] Specific examples of diacyl peroxide initiators and dialkyl peroxide initiators include dicumyl peroxide, tert-butylcumyl peroxide, di-tert-butyl peroxide, benzoyl peroxide, and lauroyl peroxide.

[0046] 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.

[0047] Specific examples of percarbonate initiators include tert-butylperoxyallyl carbonate and tert-butylperoxyisopropyl carbonate.

[0048] 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.

[0049] The composition may contain one or more types of polymerization initiators. The content of the polymerization initiator in the composition can be, for example, 0.01% by mass to 5% by mass of the entire composition.

[0050] Examples of UV absorbers that the composition may contain include benzophenone UV absorbers, cyanoacrylate UV absorbers, benzotriazole UV absorbers, malonic acid ester UV absorbers, and oxalanilide UV absorbers.

[0051] 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.

[0052] The composition may contain one or more types of ultraviolet absorbers. The content of the ultraviolet absorber in the composition can be, for example, 0.001% by mass to 1% by mass of the entire composition.

[0053] The colorants that the composition may contain include perylene dyes, perinone dyes, pyrazolone dyes, methine dyes, coumarin dyes, quinophthalone dyes, quinoline dyes, anthraquinone dyes, asdolapyridone dyes, thioindigo dyes, coumarin dyes, isoindolinone pigments, siketopi dyes, and the like. Included are lolopyrrole pigments, condensed azo pigments, benzimidazolone pigments, dioxazine pigments, copper phthalocyanine pigments, and quinacridone pigments.

[0054] The composition may contain one or more types of colorants. The content of the colorant in the composition is, for example, 1.0 × 10 -8 The content can be 0.5% by mass to 0.5% by mass.

[0055] When the composition contains additives, the total content thereof may be 15% by mass or less, 10% by mass or less, 5% by mass or less, or 1% by mass or less of the total composition. When the composition contains additives, the total content thereof may be 0.01% by mass or more, 0.05% by mass or more, or 0.1% by mass or more of the total composition.

[0056] The composition of the present disclosure may be used immediately after preparation, or may be stored before use. The storage conditions for storage are not particularly limited, but may be, for example, 0°C to 45°C. From the viewpoint of ensuring good quality, the storage temperature is preferably selected from the range of 0°C to 39°C, more preferably selected from the range of about 25°C ± 10°C, and even more preferably selected from the range of about 25°C to 30°C.

[0057] <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. 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. 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 the composition and may contain components that are not involved in polymerization. However, depending on the method for curing the composition, it may be considered to be the same as the above-mentioned polymer (i.e., not containing components that are not involved in polymerization). 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 will include a polymer of the composition of the present disclosure. The molded article is preferably a molded article containing a cured product obtained by curing only the composition of the present disclosure. The molded article may also be an object obtained by molding the polymer or cured product into any shape.

[0058] Whether or not the polymer, cured product, and molded article of the present disclosure contain methyl methacrylate, odorous components, or other components can be determined by known analytical methods, such as gas chromatography and liquid chromatography.

[0059] The polymer, cured product, and molded article of the present disclosure contain odorous components, and the concentration of the odorous components is more than 0 ppm by mass and less than 450 ppm by mass relative to the total mass of the polymer, cured product, or molded article. The concentration of odorous components contained in the polymer, cured product, or molded article may be 300 ppm by mass or less, 250 ppm by mass or less, 200 ppm by mass or less, 150 ppm by mass or less, 100 ppm by mass or less, 90 ppm by mass or less, 50 ppm by mass or less, or 25 ppm by mass or less. The concentration of the odorous component contained in the polymer, cured product, or molded article is preferably as low as possible. The concentration of the odorous component may be, for example, 0 ppm by mass relative to the entire composition, or more than 0 ppm by mass, 2 ppm by mass or more, 5 ppm by mass or more, or 10 ppm by mass or more.

[0060] When the concentration of odorous components contained in the polymer, cured product, or molded article is in the range of less than 450 ppm by mass, the odor of the polymer, cured product, or molded article is effectively suppressed.

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

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

[0063] Specifically, the composition of the present disclosure can be used, for example, to form a methyl methacrylate polymer into a sheet (molded product) by bulk polymerization. Furthermore, in cell-cast polymerization, the composition is heated under predetermined heating conditions to allow the polymerization reaction to proceed, thereby forming a cured product (molded product) from the composition.

[0064] In the method for polymerizing methyl methacrylate contained in the composition of the present disclosure or the method for producing a molded 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.

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

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

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

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

[0069] When the composition of the present disclosure is subjected to a 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.

[0070] 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.

[0071] 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.

[0072] 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.

[0073] 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.

[0074] <Uses of polymethyl methacrylate and its molded products> Polymethyl methacrylate and molded articles thereof obtained from the composition of the present disclosure have excellent light transmittance, heat resistance, and weather resistance, and are therefore 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]

[0075] Hereinafter, embodiments of the present disclosure will be described based on examples, but the present disclosure is not limited to the following examples. The results of the sensory evaluation of the odor of the compositions shown in the table were evaluated according to the following criteria. <Odor strength> 5: Extremely strong 4: Very strong 3: Strong 2: Somewhat strong 1: Odorless or not noticeable <Uncomfort level> 5: Extremely uncomfortable 4: Very uncomfortable 3: Uncomfortable 2: Slightly uncomfortable 1: Odorless or not unpleasant

[0076] Example 1 The gaseous pyrolysate obtained by pyrolyzing polymethyl methacrylate was cooled to obtain a condensate. This condensate (unpurified) was used as a composition containing methyl methacrylate. The content of methyl methacrylate was 95% by mass of the entire composition. To 3 g of the composition, 0.3 g of silver ion-containing zeolite (Zeomic BG02N, manufactured by Sinanen Zeomic Corporation) was added as an adsorbent, and the mixture was mixed. After contacting the adsorbent with the composition and leaving it to stand for 24 hours, a sensory evaluation of odor was carried out (by testers: one male and one female). The results are shown in Table 1.

[0077] <Example 2> A sensory evaluation of odor was carried out in the same manner as in Example 1, except that the adsorbent brought into contact with the composition was changed to the same amount of a zeolite-based deodorizer (Dashlight 3MH, manufactured by Sinanen Zeomic Co., Ltd.). The results are shown in Table 1.

[0078] Example 3 A sensory evaluation of odor was carried out in the same manner as in Example 1, except that the adsorbent brought into contact with the composition was changed to the same amount of a zeolite-based deodorizer (Dashlight 9MH, manufactured by Sinanen Zeomic Co., Ltd.). The results are shown in Table 1.

[0079] <Comparative Example 1> Except for not bringing the composition into contact with an adsorbent, the odor sensory evaluation was carried out in the same manner as in Example 1. The results are shown in Table 1.

[0080] [Table 1]

[0081] Example 4 Except for changing the amount of adsorbent brought into contact with the composition to 0.5 g, a sensory evaluation of odor was carried out in the same manner as in Example 1. The results are shown in Table 2.

[0082] <Example 5> Except for changing the amount of adsorbent brought into contact with the composition to 0.1 g, a sensory evaluation of odor was carried out in the same manner as in Example 1. The results are shown in Table 2.

[0083] Example 6 A sensory evaluation of odor was carried out in the same manner as in Example 1, except that the adsorbent brought into contact with the composition was changed to the same amount of activated carbon (manufactured by Daiso Industries Co., Ltd.) The results are shown in Table 2.

[0084] Example 7 A sensory evaluation of odor was carried out in the same manner as in Example 1, except that the composition brought into contact with the adsorbent was changed to a purified condensate. The content of methyl methacrylate was 97% by mass of the entire composition. The results are shown in Table 2.

[0085] Example 8 Except for changing the amount of adsorbent brought into contact with the composition to 0.1 g, a sensory evaluation of odor was carried out in the same manner as in Example 7. The results are shown in Table 2.

[0086] <Comparative Example 2> Except for not bringing the composition into contact with an adsorbent, a sensory evaluation of odor was carried out in the same manner as in Example 7. The results are shown in Table 2.

[0087] <Comparative Example 3> Instead of the adsorbent, the same amount of baking soda (a substance that exhibits deodorizing properties through a neutralization reaction with acidic substances, A sensory evaluation of odor (tester: one male) was carried out in the same manner as in Example 1, except that a fluoride-based fluoride (manufactured by Daiso Industries Co., Ltd.) was brought into contact with the composition. The results are shown in Table 2.

[0088] [Table 2]

[0089] Example 9 The gaseous pyrolysate obtained by pyrolyzing polymethyl methacrylate was cooled to obtain a condensate, which was used as a composition containing methyl methacrylate. 0.5 g of silver ion-containing zeolite (Zeomic BG02N, manufactured by Sinanen Zeomic Co., Ltd.) was added as an adsorbent to 3 g of the composition and mixed. A sensory evaluation of odor (evaluation subject: odor intensity, tester: one male) was conducted on the composition before contact with the adsorbent (0 hours), and 1 hour, 3 hours, 6 hours, and 24 hours after the start of contact with the adsorbent. The results are shown in Table 3.

[0090] Example 10 A sensory evaluation of odor was carried out in the same manner as in Example 9, except that the amount of adsorbent brought into contact with the composition was changed to 0.1 g. The results are shown in Table 3.

[0091] Example 11 A sensory evaluation of odor was carried out in the same manner as in Example 9, except that the composition brought into contact with the adsorbent was changed to the purified condensate. The results are shown in Table 3.

[0092] Example 12 Except for changing the amount of adsorbent brought into contact with the composition to 0.1 g, the odor sensory evaluation was carried out in the same manner as in Example 11. The results are shown in Table 3.

[0093] [Table 3]

[0094] <Measurement of odor component concentration> The odor of the composition containing methyl methacrylate is presumed to be caused by n-octyl mercaptan, which is added as a polymerization regulator to the raw material polymethyl methacrylate. Therefore, the following concentration measurement tests 1 and 2 were conducted to confirm whether the concentration of n-octyl mercaptan contained in the composition changes upon contact with the adsorbent.

[0095] (Concentration measurement test 1) In Example 9, the concentration of n-octyl mercaptan was measured by gas chromatography for the composition before contact with the adsorbent (0 hour), and 2 hours, 3 hours, 7 hours, and 24 hours after the start of contact. The measurement conditions are shown below.

[0096] (Measurement conditions) Equipment: GC-2010 Plus (manufactured by Shimadzu Corporation) Column: DB-1 (Agilent Technologies) Detector: FID 2010 Plus (Shimadzu Corporation) Column oven conditions Initial temperature: 40°C (hold time 1 minute) Heating rate: 8°C / min Intermediate temperature: 120℃ (hold time 0 minutes) Heating rate: 20°C / min Final temperature: 300°C (hold time 10 minutes) Sample vaporization conditions Vaporization chamber temperature: 300℃ Carrier gas: Helium Pressure: 50kPa Total flow rate: 220.1mL / min Column flow rate: 1.08 mL / min Linear speed: 31.1cm / sec Purge dose: 3.0mL / min Split ratio: 200 Detector conditions Detector temperature: 300℃ Sampling rate: 40msec Make-up gas: N2 Make-up flow rate: 30 mL / min H2 flow rate: 40mL / min Air flow rate: 400mL / min Autosampler conditions Injection volume: 1μL

[0097] The peak area (a1) corresponding to octyl mercaptan and the peak area (b1) corresponding to dodecanol detected when the sample (composition contacted with the adsorbent) was measured under the above measurement conditions were measured. From these peak areas, the peak area ratio A (=a1 / b1) was calculated.

[0098] A standard sample with a mass ratio of octyl mercaptan to dodecanol of W0 (known) was measured under the above measurement conditions, and the peak area (a0) corresponding to the detected n-octyl mercaptan and the peak area (b0) corresponding to dodecanol were measured. From these peak areas, the peak area ratio A0 (=a0 / b0) was calculated. Next, the factor f (=W0 / A0) was calculated from the peak area ratio A0 and the above mass ratio W0.

[0099] Next, the mass ratio W of n-octyl mercaptan to dodecanol contained in the composition was calculated by multiplying the peak area ratio A by the factor f. The concentration of n-octyl mercaptan contained in the composition (OM concentration, mass ppm) was calculated from the calculated mass ratio W and the mass of the composition. The results are shown in Table 4.

[0100] [Table 4]

[0101] (Concentration measurement test 2) For the above Examples 1 and 4 to 8, the n-octyl mercaptan concentration (OM concentration, mass ppm) was measured when a sensory evaluation of odor was conducted (compositions after standing for 24 hours). The measurement method was the same as above. The results are shown in Table 5.

[0102] [Table 5]

[0103] The results shown in Tables 1 to 3 suggest that contacting a composition containing polymethyl methacrylate with an adsorbent is effective in suppressing the odor of the composition. The results shown in Tables 4 and 5 suggest that the adsorbent in contact with the composition adsorbs substances contained as odorous components, contributing to a reduction in the concentration of odorous components in the composition.

Claims

1. Contains methyl methacrylate and odorous components, the odor component is at least one selected from the group consisting of n-octyl mercaptan and n-dodecyl mercaptan, A composition having an odorous component concentration of more than 0 ppm by mass and less than 450 ppm by mass of the entire composition.

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

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

4. The composition according to claim 1, wherein the concentration of odorous components is 2 ppm by mass or more and 300 ppm by mass or less based on the total composition.

5. The composition according to claim 1, wherein the concentration of odorous components is 250 ppm by mass or less of the total composition.

6. The composition according to claim 1, wherein the concentration of odorous components is 100 ppm by mass or less based on the total composition.

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

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

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

10. A polymer comprising a structural unit derived from methyl methacrylate contained in the composition according to any one of claims 1 to 9.

11. A molded article comprising the polymer of claim 10.

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

13. A molded article comprising the cured product according to claim 12.

14. 10. An adsorbent for use in a method for producing methyl methacrylate, comprising contacting the composition of claim 1 with the adsorbent, The adsorbent contains zeolite containing silver ions, is in the form of beads, and has a particle diameter of 1 mm to 7 mm.

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