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

Abstract

The present invention addresses the problem of providing a composition having excellent storage stability, a polymer obtained using the composition, a cured product, and a molded article, and a method for producing polymethyl methacrylate using the composition. The present invention relates to a composition containing methyl methacrylate and an alcohol having 4 carbon atoms, the concentration of the alcohol having 4 carbon atoms being 5 ppm by mass to 10000 ppm by mass of the entire composition.

Description

Technical Field

[0001] This disclosure relates to methods for manufacturing compositions, polymers, cured products, molded articles, and polymethyl methacrylate. Background Technology

[0002] Poly(methyl)methacrylate (PMMA), obtained by polymerizing PMMA, is used in various fields as a resin material with excellent transparency and durability. Furthermore, with the rise in resource prices in recent years and the resulting increased awareness of environmental issues, there is a growing demand for the recycling and reuse (recycling) of PMMA products (molded bodies) used for various purposes as described above.

[0003] Methods for reusing poly(methyl methacrylate) include, for example, raw material reuse, where recycled molded bodies are re-molded to produce new molded bodies; chemical recycling, where poly(methyl methacrylate) is thermally decomposed (depolymerized) by heat treatment of the recycled molded bodies to recover the (methyl methacrylate), and the recovered (methyl methacrylate) (sometimes called recycled MMA or recycled MA) is used to produce new molded bodies; and thermal cycling, where the recycled molded bodies are burned as fuel, and the combustion energy is used directly as a heat source to generate electricity.

[0004] In addition, due to the diversification of applications of poly(methyl methacrylate) in recent years, technologies for improving the quality of poly(methyl methacrylate) are being researched.

[0005] For example, as a polymerization apparatus suitable for obtaining high-quality poly(meth)acrylate, a polymerization apparatus has been proposed that can suppress the formation of gels in the reaction tank where the raw material monomers and polymerization initiators react (see Patent Document 1).

[0006] Existing technical documents

[0007] Patent documents

[0008] Patent Document 1: Japanese Patent Application Publication No. 2012-102190 Summary of the Invention

[0009] In addition to improving the polymerization process of raw material monomers as described in Patent Document 1, as a solution to improve the quality of poly(meth)acrylate, a solution to suppress the quality degradation of raw material monomers during storage can be cited.

[0010] In view of the above, one embodiment of this disclosure aims to provide a composition with excellent storage stability, particularly under long-term storage conditions, a polymer obtained using the composition, a cured product and a molded article, and a method for manufacturing polymethyl methacrylate using the composition.

[0011] The means for solving the above-mentioned problems include the following implementation methods.

[0012] <1> A composition comprising methyl methacrylate and an alcohol having 4 carbon atoms, wherein the concentration of the alcohol having 4 carbon atoms is 5 ppm to 10,000 ppm by mass of the whole composition.

[0013] <2> According to the composition described in <1>, the content of methyl methacrylate is 85% or more by mass of the whole composition.

[0014] <3> The composition according to <1> or <2>, wherein the content of methyl methacrylate is more than 90% by mass of the whole composition.

[0015] <4> The composition according to any one of <1> to <3>, wherein the concentration of the alcohol having 4 carbon atoms is 5 ppm to 6000 ppm by mass of the whole composition.

[0016] <5> The composition according to any one of <1> to <4>, wherein the concentration of the alcohol having 4 carbon atoms is 50 ppm to 6000 ppm by mass of the whole composition.

[0017] <6> The composition according to any one of <1> to <5>, wherein the alcohol having 4 carbon atoms is n-butanol.

[0018] <7> The composition according to any one of <1> to <6>, wherein the methyl methacrylate comprises recycled methyl methacrylate or biologically derived methyl methacrylate.

[0019] <8> The composition according to any one of <1> to <7>, wherein it further comprises (meth)acrylates other than methyl methacrylate.

[0020] <9> The composition according to any one of <1> to <7>, wherein it further comprises a polymer containing structural units derived from methyl methacrylate.

[0021] <10> A polymer comprising methyl methacrylate structural units contained in any one of <1> to <9>.

[0022] <11> A molded article comprising the polymer described in <10>.

[0023] <12> A cured product, which is a cured product of the composition described in any one of <1> to <9>.

[0024] <13> A molded body comprising the cured material described in <12>.

[0025] <14> A method for manufacturing polymethyl methacrylate, comprising the step of polymerizing the methyl methacrylate contained in any one of <1> to <9>.

[0026] According to one embodiment of the present disclosure, a composition with excellent storage stability, particularly under long-term storage conditions, a polymer obtained using the composition, a cured product and a molded article, and a method for manufacturing polymethyl methacrylate using the composition can be provided. Detailed Implementation

[0027] The embodiments of the present invention will be described below. However, the present invention is not limited to the following embodiments.

[0028] In this specification, the numerical range represented by “~” includes the minimum and maximum values ​​recorded before and after the “~”, respectively.

[0029] Within the numerical ranges described in this specification, the upper or lower limit of a numerical range can be replaced with the upper or lower limit of a numerical range described in other periods. Furthermore, within the numerical ranges described in this specification, the upper or lower limit of that range can be replaced with the values ​​shown in the embodiments.

[0030] <Composition>

[0031] The compositions disclosed herein contain methyl methacrylate and an alcohol having four carbon atoms.

[0032] Based on the total mass of the composition, the concentration of the alcohol with 4 carbon atoms is 5 ppm to 10,000 ppm by mass.

[0033] As shown in the examples described below, the compositions of this disclosure exhibit excellent storage stability.

[0034] (Methyl methacrylate)

[0035] The compositions disclosed herein contain methyl methacrylate.

[0036] In this disclosure, "methyl methacrylate" refers to methyl methacrylate that is not substantially free of impurities such as byproducts generated during the synthesis of methyl methacrylate. However, without prejudice to the purpose of the invention, the methyl methacrylate of this disclosure is not limited thereto. In other words, "methyl methacrylate" may contain impurities that cannot be completely removed by purification methods according to conventional methods, or may contain impurities in amounts that are undetectable by detection methods according to conventional methods.

[0037] There is no particular limitation on the content of methyl methacrylate in the composition, and it can be selected according to the intended use of the polymethyl methacrylate obtained by using the composition. For example, the content of methyl methacrylate can be 85% or more by mass, 90% or more by mass, 95% or more by mass, or 99% or more of the total composition.

[0038] If the content of methyl methacrylate in the composition is within the above range, then the polymer obtained by polymerizing the composition and the molded body containing it are preferred, at least from the viewpoint of heat resistance or surface hardness.

[0039] The methyl methacrylate contained in the composition can be synthesized using well-known synthetic methods. There are no particular limitations on the synthetic method; it can be the ACH method, the C4 direct oxidation method, or the α method.

[0040] The methyl methacrylate contained in the composition may include recycled methyl methacrylate.

[0041] In this disclosure, recycled methyl methacrylate refers to methyl methacrylate obtained by depolymerization of polymethyl methacrylate (a reaction in which the polymer decomposes to generate monomers).

[0042] The depolymerization of polymethyl methacrylate (PMMA) can be achieved, for example, by heating PMMA.

[0043] There are no particular restrictions on the source of polymethyl methacrylate (PMMA) that can be used as a raw material for recycled PMMA, as long as PMMA can be recycled. For example, the source of PMMA can be a molded body containing PMMA.

[0044] The methyl methacrylate contained in the composition may include biologically derived methyl methacrylate.

[0045] In this disclosure, biologically derived methyl methacrylate refers to methyl methacrylate synthesized from biologically derived raw materials. Biologically derived raw materials can be plant-based or animal-based, but are preferably plant-based.

[0046] (Alcohols with 4 carbon atoms)

[0047] The compositions disclosed herein contain an alcohol having four carbon atoms. The alcohol having four carbon atoms in the composition may be at least one selected from n-butanol, isobutanol, sec-butanol, and tert-butanol. From the viewpoint of storage stability of the composition, n-butanol is preferred.

[0048] The concentration of alcohols with 4 carbon atoms in the composition is 5 ppm to 10,000 ppm by mass of the whole composition.

[0049] From the viewpoint of long-term storage stability of the composition, the concentration of the alcohol containing 4 carbon atoms in the composition is preferably 10 ppm by mass or more, more preferably 20 ppm by mass or more, and even more preferably 50 ppm by mass or more.

[0050] From the viewpoint of optical stability of the composition, the concentration of the alcohol containing 4 carbon atoms in the composition 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.

[0051] Furthermore, from the viewpoint of the heat resistance of the polymer, cured product, and molded article formed from the composition described later, the concentration of the alcohol containing 4 carbon atoms in the composition is preferably 10 ppm by mass or more, more preferably 20 ppm by mass or more, even more preferably 50 ppm by mass or more, and preferably 6000 ppm by mass or less of the whole composition.

[0052] As needed, the composition may contain components that are not methyl methacrylates or alcohols having four carbon atoms. For example, the composition may contain (meth)acrylates other than methyl methacrylates described below, polymers containing structural units derived from methyl methacrylates, low-content components, or additives.

[0053] ((meth)acrylate)

[0054] In addition to methyl methacrylate, the composition may also contain other (meth)acrylates (hereinafter also simply referred to as (meth)acrylates).

[0055] Examples of (meth)acrylates include methyl acrylate, ethyl acrylate, propyl acrylate, n-butyl acrylate, sec-butyl acrylate, tert-butyl acrylate, cyclohexyl acrylate, benzyl acrylate, 2-ethylhexyl acrylate, 2-hydroxyethyl acrylate, and cyclopentyl acrylate. Among these, methyl acrylate or ethyl acrylate is preferred, and methyl acrylate is more preferred. These can be used alone or in combination of two or more.

[0056] In this disclosure, "(meth)acrylate" means that it can be either acrylate or methacrylate.

[0057] (Meth)acrylates may be included in the composition as a byproduct generated during the manufacture of methyl methacrylate or the regeneration of polymethyl methacrylate, or may be intentionally incorporated into the composition.

[0058] When the composition contains (meth)acrylate, the concentration is preferably 50,000 ppm by mass or less of the total composition, more preferably 40,000 ppm by mass or less, and even more preferably 30,000 ppm by mass or less.

[0059] If the composition contains other (meth)acrylates, the concentration may be 1 ppm or more by mass, 2 ppm or more by mass, or 5 ppm or more by mass of the whole composition.

[0060] In addition to containing methyl methacrylate, the composition may contain a polymer comprising structural units derived from methyl methacrylate. This polymer may be a homopolymer of methyl methacrylate or a copolymer of other (meth)acrylates capable of polymerizing with methyl methacrylate. Examples of other (meth)acrylates capable of polymerizing with methyl methacrylate include the same (meth)acrylates described above.

[0061] (Low content ingredient)

[0062] The composition may contain low amounts of components other than alcohols having four carbon atoms. These low-content components may be included in the composition as byproducts generated during the manufacture of methyl methacrylate or the regeneration of polymethyl methacrylate.

[0063] In this disclosure, a low-content component refers to a component contained in the composition at a concentration of less than 10,000 ppm by mass.

[0064] Examples of low-content components other than alcohols with four carbon atoms that can be included in a composition include carboxylic acid esters, aromatic hydrocarbon compounds, aliphatic hydrocarbon compounds, alcohols other than alcohols with four carbon atoms, and butyl acrylate.

[0065] The composition may contain only one or more low-content components other than alcohols with four carbon atoms.

[0066] As carboxylic acid esters, examples include methyl isobutyrate, methyl propionate, methyl 2,4-dimethyl-4-pentenoate, methyl 2-methyl-3-butenoate, methyl cis-glycate, methyl 3-methyl-3-butenoate, methyl 3-methyl-2-butenoate, dimethyl itaconic acid, and dimethyl 2-methyl-5-methylene adipate.

[0067] As aromatic hydrocarbon compounds, toluene and styrene are examples.

[0068] As aliphatic hydrocarbon compounds, 1-octene and 1-octadecene are examples.

[0069] When the composition contains low-content components other than alcohols with 4 carbon atoms, the concentration of each low-content component is preferably 8000 ppm by mass or less of the total composition, more preferably 6000 ppm by mass or less, and even more preferably 5000 ppm by mass or less.

[0070] When the composition contains low-content components other than alcohols with 4 carbon atoms, the concentration of each low-content component can be 1 ppm or more, 2 ppm or more, or 5 ppm or more by mass of the whole composition.

[0071] (additive)

[0072] The composition may contain additives as needed. Examples of additives include mold release agents, polymerization regulators, polymerization initiators, UV absorbers, and colorants.

[0073] The composition may contain only one additive or two or more additives.

[0074] Examples of release agents that may be contained in a composition include higher fatty acid esters, higher aliphatic alcohols, higher fatty acids, higher fatty acid amides, higher fatty acid metal salts, and fatty acid derivatives.

[0075] Specific examples of release agents include sodium di-(2-ethylhexyl)sulfosuccinate, stearyl alcohol, methyl stearate, and stearamide.

[0076] The composition may contain only one type of release agent or two or more types.

[0077] The content of the release agent in the composition can be, for example, 0.01% to 1.0% by mass of the whole composition.

[0078] As a polymerization regulator (an additive that adjusts the polymerization rate of the polymerization reaction) that can be contained in the composition, any suitable polymerization regulator known in the past can be used. For example, a compound that can adjust the polymerization rate in a downward direction can be used as such a polymerization regulator.

[0079] Specific examples of polymerization regulators include thiols such as n-butanethiol and n-octanethiol, limonene, geraniol, α-terpinene, β-terpinene, γ-terpinene, terpinene oil, β-pinene, α-pinene, and α-methylstyrene dimers.

[0080] The composition may contain only one type of polymerization regulator or two or more types.

[0081] The content of the polymerization regulator in the composition can be, for example, 0.001% to 0.5% by mass of the whole composition.

[0082] Examples of polymerization initiators that may be included in a composition include free radical polymerization initiators, diacyl peroxide initiators, dialkyl peroxide initiators, ester peroxide initiators, percarbonate initiators, and ketal peroxide initiators.

[0083] Specific examples of free radical polymerization initiators include azo compounds such as 1,1'-azobis(cyclohexane-1-formonitrile), 2,2'-azobis(2,4,4-trimethylpentene), 2,2'-azobis(2-methylpropane), 2-cyano-2-propylazoformamide, 2,2'-azobis(2-hydroxy-methylpropionate), 2,2'-azobis(2-methyl-butyronitrile), 2,2'-azobisisobutyronitrile, 2,2'-azobis[2-(2-imidazolin-2-yl)propane], and dimethyl 2,2'-azobis(2-methylpropionate).

[0084] Specific examples of diacyl peroxide initiators and dialkyl peroxide initiators include dicumyl peroxide, tert-butyl cumyl peroxide, di-tert-butyl peroxide, benzoyl peroxide, and lauroyl peroxide.

[0085] Specific examples of ester peroxide initiators include tert-butyl peroxide-3,3,5-trimethylhexanoate, tert-butyl peroxylaurate, tert-butyl peroxyisobutyrate, tert-butyl peroxyacetate, di-tert-butyl peroxyhexahydroterephthalate, di-tert-butyl peroxyazelate, tert-butyl peroxide-2-ethylhexanoate, 1,1,3,3-tetramethylbutyl peroxide-2-ethylhexanoate, and tert-amyl peroxide-2-ethylhexanoate.

[0086] Specific examples of percarbonate initiators include allyl percarbonate tert-butyl peroxide and isopropyl percarbonate tert-butyl peroxide.

[0087] Specific examples of peroxide ketal initiators include 1,1-di-tert-butylperoxidecyclohexane, 1,1-di-tert-butylperoxide-3,3,5-trimethylcyclohexane, and 1,1-di-tert-hexylperoxide-3,3,5-trimethylcyclohexane.

[0088] The composition may contain only one type of polymerization initiator or two or more types.

[0089] The content of polymerization initiator in the composition can be, for example, 0.01% to 5% by mass of the whole composition.

[0090] Examples of UV absorbers that can be included in a composition include benzophenone UV absorbers, cyanoacrylate UV absorbers, benzotriazole UV absorbers, malonate UV absorbers, and oxaloaniline UV absorbers.

[0091] 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.

[0092] The composition may contain only one type of ultraviolet absorber or two or more types.

[0093] The content of the ultraviolet absorber in the composition can be, for example, 0.001% to 1% by mass of the whole composition.

[0094] Examples of coloring agents that can be included in a composition include perylene dyes, violet ketone dyes, pyrazolone dyes, methyl alkali dyes, coumarin dyes, quinoline dyes, quinoline dyes, anthraquinone dyes, anthraquinone dyes, thio-indolinone dyes, coumarin dyes, isoindolone pigments, diketopyrrole pigments, condensed azo pigments, benzimidazolone pigments, and dioxindolone pigments. Phthalate pigments, copper phthalocyanine pigments, and quinacridone pigments.

[0095] The composition may contain only one type of colorant or two or more types.

[0096] The content of colorant in the composition can be, for example, 1.0 × 10⁻⁶ of the total composition. -8 Mass %~0.5% of mass.

[0097] When the composition contains additives, the total content may be less than 15% by mass, less than 10% by mass, less than 5% by mass, or less than 1% by mass of the whole composition.

[0098] When the composition contains additives, the total content may be 0.01% by mass or more, 0.05% by mass or more, or 0.1% by mass or more of the whole composition.

[0099] The storage conditions for the compositions disclosed herein are not particularly limited, but may be, for example, 0°C to 35°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 from the range of about 25°C ± 10°C, and even more preferably from the range of about 25°C to 30°C.

[0100] The compositions disclosed herein exhibit excellent storage stability. Specifically, they are able to maintain an inhibited polymerization reaction during storage. In this disclosure, the storage stability of the compositions is assessed by evaluating the storage stability by confirming the presence or absence of polymer formation in the compositions stored under accelerated conditions, and by measuring the total light transmittance of the compositions stored under accelerated conditions. The methods for evaluating storage stability and measuring total light transmittance will be described below.

[0101] In the embodiments described later, the storage stability of the composition was evaluated in sequence as follows: (1) a composition containing methyl methacrylate and alcohol was prepared; (2) a storage test was performed, including steps 1 to 7 described below in sequence; and (3) the appearance of the solution obtained by adding the composition after the storage test to a poor solvent was observed by visual inspection.

[0102] Step 1: Inject 25 mL of the composition into the lower part of the pressure vessel (TVS-N2 type, manufactured by Pressure Glass Industry Co., Ltd.).

[0103] Step 2: Clamp the gasket between the upper and lower parts of the pressure vessel to seal the pressure vessel.

[0104] Step 3: Nitrogen is supplied from the front end of the upper part of the pressure vessel and sealed in at an internal pressure of 0.2 MPa. Confirm that the internal pressure does not change within 1 minute.

[0105] Step 4: Remove the internal pressure inside the pressure vessel and install a sealing plug at the front end of the upper part of the pressure vessel.

[0106] Step 5: Place the pressure vessel into an oil bath set to 60°C.

[0107] Step 6: Store in an oil bath for 72 hours.

[0108] Step 7: After 72 hours, remove the pressure vessel from the oil bath and place it in ice-cold water for rapid cooling.

[0109] In (3) above, a suitable solvent is chosen that does not dissolve the polymer formed in the composition. In the examples described later, n-hexane was used. Visually, the lower the degree of turbidity or precipitation in the solution, the more effectively the polymerization reaction of methyl methacrylate can be suppressed.

[0110] In the embodiments described later, the determination of the total light transmittance of the composition stored under accelerated conditions was performed by measuring the total light transmittance of the composition after storage. Specifically, using the stored composition, the total light transmittance Tt (%) of light in the wavelength range of 500 nm to 780 nm with an optical path length of 10 mm was measured. A spectrophotometer (Hitachi High Tech Fielding Co., Ltd. "Hitachi Spectrophotometer U-4000") was used for the measurement, but a suitable commercially available spectrophotometer may also be used. A higher total light transmittance indicates that the optical properties of the composition, such as transparency, are better maintained. The total light transmittance of the composition stored under accelerated conditions is preferably greater than 97%, more preferably 98% or higher.

[0111] <Polymers, Cured Products, and Molded Products>

[0112] The polymers disclosed herein are polymers comprising structural units derived from methyl methacrylate contained in the compositions of this disclosure described above. Here, a polymer refers to a polymer formed by polymerizing the polymerization-related components contained in the composition, and is a polymer having structural units derived from the polymerization-related components. The polymers of this disclosure may contain structural units derived from methyl methacrylate contained in the compositions of this disclosure and structural units derived from other polymerization components. The weight-average molecular weight of the polymers of this disclosure is not particularly limited and can be selected according to the intended use of the polymer.

[0113] The cured product of this disclosure is a cured product of the composition described above. Here, a cured product refers to a substance obtained by curing the composition, and may also contain components unrelated to polymerization. However, depending on the method of curing the composition, it may also be considered the same as the polymer described above (i.e., not containing components unrelated to polymerization).

[0114] The molded articles disclosed herein comprise the polymers or cured products of the present disclosure as described above. When the cured product is considered to be the same as the polymer, the molded article comprises a polymer of the compositions of the present disclosure. Preferably, the molded article comprises a cured product obtained solely by curing the compositions of the present disclosure. The molded article can be an object formed by molding the polymer or cured product into any shape.

[0115] (Physical properties of polymers and cured products)

[0116] The polymers and cured products disclosed herein exhibit excellent heat resistance and optical properties. Specifically, compared to polymers or cured products obtained from compositions containing methyl methacrylate and not containing alcohols with four carbon atoms, they exhibit similar Vicat softening temperatures and show a tendency for the total light transmittance in the wavelength range of 380 nm to 780 nm to be less reduced after accelerated degradation treatment.

[0117] The Vicat softening temperature indicates the heat resistance of polymers and cured products. Specifically, it serves as an indicator of the ease with which they can be deformed in high-temperature environments. A high Vicat softening temperature means that, for example, when used outdoors, the polymer or cured product is less prone to deformation even when exposed to high temperatures under direct sunlight, and can be used. In this disclosure, the determination of the Vicat softening temperature can be performed using any suitable apparatus and method known in the prior art. In the embodiments described later, the Vicat softening temperature is determined using a heat distortion tester ("148-6-type" manufactured by Yasuda Seiki Co., Ltd.) according to JIS K7206 (B50 method). For example, a cast plastic sheet described later can be used as the test piece for the determination.

[0118] The specific method for determining the Vicat softening temperature is described below. First, a 25mm × 25mm × 3mm test piece made of cast plastic sheet was stored at 83°C for 16 hours. Then, it underwent a conditioning treatment by cooling in a desiccator at 23±5°C for at least 1 hour. For the condition-conditioned test piece, the Vicat softening temperature (°C) was determined using a heat distortion tester ("148-6-cell type" manufactured by Yasuda Seiki Co., Ltd.) according to JIS K7206 (B50 method).

[0119] Optical properties, more specifically total light transmittance, represent the transparency of polymers and cured products. In this disclosure, the measurement of total light transmittance can be performed after the polymer or cured product has undergone accelerated degradation treatment. This method allows for efficient evaluation of the transparency of polymers or cured products after prolonged use.

[0120] In the embodiments described later, the total light transmittance Tt (%) of light in the wavelength range of 380 nm to 780 nm was measured using the molded body after accelerated degradation treatment. A commercially available spectrophotometer (Hitachi HighTech Fielding Co., Ltd. "Hitachi Spectrophotometer U-4000") was used for the measurement.

[0121] The specific method for measuring the total light transmittance of this disclosure will be described below. First, a 50mm × 50mm × 3mm test piece made of polymer or cured material is subjected to accelerated degradation treatment, placed in a thermostat (Vacuum Oven VOS-301SD manufactured by Tokyo Rikka Kiki Co., Ltd.) at 80°C for 200 hours. Next, using the accelerated degradation test piece, the total light transmittance Tt (%) of light in the wavelength range of 380nm to 780nm with an optical path length of 50mm is measured. The measurement is performed using a spectrophotometer (Hitachi High Tech Fielding Co., Ltd. "Hitachi Spectrophotometer U-4000"). From the viewpoint of optical properties, the total light transmittance of the polymer or cured material after accelerated degradation treatment is preferably 81% or more, more preferably 81.5% or more.

[0122] Whether the polymer and cured product of this disclosure contain methyl methacrylate, an alcohol with four carbon atoms, or other components can be determined using known analytical methods. Examples of known analytical methods include gas chromatography and liquid chromatography.

[0123] <Method for manufacturing polymethyl methacrylate>

[0124] The method for manufacturing polymethyl methacrylate disclosed herein includes a step of polymerizing the methyl methacrylate contained in the composition of the present disclosure described above. Here, the polymer obtained from the composition of the present disclosure also conforms to the polymethyl methacrylate of the present disclosure, and the cured product obtained from the composition also conforms to the polymethyl methacrylate of the present disclosure.

[0125] There are no particular limitations on the method for polymerizing the methyl methacrylate contained in the composition, and it can be carried out using known methods. For example, it can be carried out using bulk polymerization, unit casting polymerization, solution polymerization, suspension polymerization, emulsion polymerization, etc.

[0126] Specifically, for the compositions disclosed herein, for example, a sheet (molded body) formed by molding a polymer of methyl methacrylate can be obtained by bulk polymerization. Alternatively, in unit casting polymerization, the composition is subjected to heat treatment under specified heating conditions to advance the polymerization reaction, thereby obtaining a cured product (molded body) formed by curing the composition.

[0127] In the method of polymerizing methyl methacrylate contained in the composition disclosed herein or in the method of manufacturing the molded article, the heating temperature and heating time in the heating conditions can be set, for example, taking into account the type and content of the selected polymerization regulator, polymerization initiator and / or other components.

[0128] In unitary casting polymerization, the heating temperature can be set to, for example, 50°C to 120°C when manufacturing the cured product and its molded body. Additionally, the heating time during manufacturing can be set to, for example, 1 hour to 20 hours. Furthermore, the heat treatment can be a heat treatment comprising multiple steps with different heating temperatures and / or heating times.

[0129] The cured product and its molded body obtained by unit casting polymerization can be manufactured, for example, by performing heat treatment under heating conditions including steps 1 to 7 below.

[0130] Step 1: Heat from room temperature to 68℃ over a period of 20 minutes.

[0131] Step 2: Maintain 68℃ for 90 minutes.

[0132] Step 3: The temperature was lowered from 68℃ to 64℃ over a period of 20 minutes.

[0133] Step 4: Maintain 64℃ for 90 minutes.

[0134] Step 5: The temperature rises from 64℃ to 123℃ over a period of 10 minutes.

[0135] Step 6: Maintain at 123℃ for 120 minutes.

[0136] Step 7: Cool down from 123℃ to room temperature over a period of 78 minutes.

[0137] In the manufacturing method of the cured material and its molded body, if steps 1 to 7 above are carried out sequentially, the heat generated in the polymerization reaction can be suppressed, and polymerization can be completed stably.

[0138] When the composition of this disclosure is heat-treated, a molded article of a predetermined shape can be formed, for example, by applying a unit casting method (unit casting polymerization) using units that can internally divide a closed space of a predetermined shape. Hereinafter, a method for manufacturing a molded article using the unit casting method will be specifically described.

[0139] When manufacturing a molded body using the unit casting method, the first step is to prepare the unit. Here, an example of forming a molded body (sometimes called a cast plate) as a plate-like body will be explained.

[0140] Such a unit may consist of at least two flat plate components and a sealing material (gasket), wherein the sealing material (gasket) is configured to be sandwiched between the two flat plate components and is capable of sealing the gap between the two flat plate components configured in an opposing manner to form a sealed space.

[0141] The flat plate component can be a single sheet or a strip. The flat plate component is made of a material that will not dissolve in the disclosed composition, will not hinder the polymerization reaction of the composition, and has sufficient heat resistance to the heating temperature during heat treatment. Examples of preferred materials for the flat plate component include glass and metal.

[0142] As a sealing material, any suitable sealing material known in the art can be used. The sealing material is composed of a material that will not dissolve in the composition disclosed herein, will not hinder the polymerization reaction of the composition, and has sufficient heat resistance to the heating temperature during heat treatment. A preferred specific example of a sealing material is a gasket made of vinyl chloride resin.

[0143] Next, the composition of this disclosure is injected into the gaps (voids) divided by the prepared unit as described above, using any suitable method known in the prior art. Then, the unit is heat-treated under the heating conditions already described. There are no particular limitations on the method for heat-treating the unit in which the composition of this disclosure is injected. The method for heat-treating the unit is similar to the conventional unit casting method, for example, it can be a method of directly heat-treating the unit from the outside using a hot air circulating furnace, an infrared heater, etc., and further providing any suitable conventional sleeve on the outside of the unit, and introducing a heat medium such as warm air, warm water, or steam into the sleeve.

[0144] <Uses of polymethyl methacrylate and its molded articles>

[0145] The polymethyl methacrylate and its molded articles obtained from the compositions of this disclosure exhibit excellent light transmittance, heat resistance, and durability. Therefore, they can be exposed to the external environment and to heat sources and light sources, making them suitable for various applications such as lighting fixtures, automotive parts, signage, and building materials.

[0146] Example

[0147] The following describes implementation methods of this disclosure based on examples. These examples do not limit the scope of this disclosure.

[0148] <Example 1>

[0149] Composition 1 was prepared by adding 0.001% by mass of n-butanol (manufactured by Fujifilm and Koichi Chemical Co., Ltd.) as an alcohol to 99.999% by mass of methyl methacrylate and mixing. The resulting composition 1 was in the form of a solution.

[0150] <Examples 2-5 and Comparative Examples 1-6>

[0151] The compositions were prepared in the same manner as in Example 1, except that the alcohol added to the methyl methacrylate and its concentration (ppm by mass) were changed from those in Example 1 to those shown in Table 1. All resulting compositions were in solution form.

[0152] As an alcohol, n-butanol, methanol, or ethanol (all manufactured by Fujifilm and Kojun Pharmaceutical Co., Ltd.) are used.

[0153] (1) Evaluation of the storage stability of the composition

[0154] For the compositions prepared in Examples 1-5 and Comparative Examples 1-6, storage tests were performed, including steps 1-7 as described below. To evaluate the stability after long-term storage, the storage tests were conducted under accelerated conditions (60°C).

[0155] Step 1: Inject 25 mL of the composition into the lower part of the pressure vessel (TVS-N2 type, manufactured by Pressure Glass Industry Co., Ltd.).

[0156] Step 2: Clamp the gasket between the upper and lower parts of the pressure vessel to seal the pressure vessel.

[0157] Step 3: Nitrogen is supplied from the front end of the upper part of the pressure vessel and sealed in at an internal pressure of 0.2 MPa. Confirm that the internal pressure does not change within 1 minute.

[0158] Step 4: Remove the internal pressure inside the pressure vessel and install a sealing plug at the front end of the upper part of the pressure vessel.

[0159] Step 5: Place the pressure vessel into an oil bath set to 60°C.

[0160] Step 6: Store in an oil bath for 72 hours.

[0161] Step 7: After 72 hours, remove the pressure vessel from the oil bath and place it in ice water for rapid cooling.

[0162] The composition (2 mL) after the storage test was added to 10 mL of n-hexane in a 25 mL bottle and allowed to stand. The appearance of the solution in the bottle was then visually observed, and the state of the solution was evaluated according to the following criteria. The lower the degree of turbidity or precipitation in the solution, the more further the polymerization reaction of methyl methacrylate was inhibited. The results are shown in Table 1.

[0163] (Evaluation Criteria)

[0164] A (Excellent): No clear turbidity or precipitation was detected.

[0165] B (Good): Clear turbidity or precipitation is observed, but to a small degree.

[0166] C (Unacceptable): Clear turbidity or precipitation can be confirmed, and the degree is large.

[0167] The composition (3 mL) after the storage test was placed into a quartz glass unit (T-1, Taiko Manufacturing Co., Ltd.) measuring 10 mm x 10 mm x 45 mm. Using the composition placed in the quartz glass unit, the total light transmittance Tt (%) of light in the wavelength range of 500 nm to 780 nm with an optical path length of 10 mm was measured. A spectrophotometer (Hitachi High Tech Fielding Co., Ltd. "Hitachi Spectrophotometer U-4000") was used for the measurement. A higher total light transmittance indicates that optical properties such as high transparency are maintained even after storage. The results are shown in Table 1.

[0168]

[0169] As shown in Table 1, the compositions of Examples 1-5, in which n-butanol was added to methyl methacrylate, exhibited suppressed polymerization of methyl methacrylate during storage tests compared to Comparative Example 1, in which no alcohol was added to methyl methacrylate, Comparative Examples 2-4, in which methanol was added to methyl methacrylate, or Comparative Examples 5-6, in which ethanol was added to methyl methacrylate. Based on these results, the compositions of Examples 1-5 demonstrate excellent storage stability.

[0170] (2) Evaluation of the physical properties of the molded body

[0171] Molded articles were prepared using the compositions of Examples 1-5 and Comparative Example 1, and the following physical property evaluations were performed.

[0172] The composition prepared as described above (99.85 parts by weight), sodium di-(2-ethylhexyl)sulfosuccinate (0.05 parts by weight) as a release agent, terpinene (0.01 parts by weight) as a polymerization regulator, 2,2'-azobisisobutyronitrile (0.08 parts by weight) as a polymerization initiator, and 2-(2'-hydroxy-5'-methylphenyl)benzotriazole (0.01 parts by weight) as a UV absorber are added to a glass container and mixed to obtain a composition for molding. The obtained composition is in solution form.

[0173] Prepare the following unit: a 3.8mm thick vinyl chloride resin gasket is held between two opposing glass plates, which can divide the surrounding enclosed space between the two glass plates. The composition for forming the molded body prepared as described above is injected into this space. The unit containing the injected composition is placed in an oven and heated under the heating conditions described in steps 1 to 7 below, thereby polymerizing methyl methacrylate. This produces a cast plastic sheet as a molded body of 250mm × 250mm × 3mm.

[0174] Step 1: Heat from room temperature to 68℃ over a period of 20 minutes.

[0175] Step 2: Maintain 68℃ for 90 minutes.

[0176] Step 3: The temperature was lowered from 68℃ to 64℃ over a period of 20 minutes.

[0177] Step 4: Maintain 64℃ for 90 minutes.

[0178] Step 5: The temperature rises from 64℃ to 123℃ over a period of 10 minutes.

[0179] Step 6: Maintain at 123℃ for 120 minutes.

[0180] Step 7: Cool down from 123℃ to room temperature over 90 minutes.

[0181] To evaluate the heat resistance of the obtained molded articles, the following tests were conducted.

[0182] Test pieces measuring 25mm × 25mm × 3mm from cast plastic sheets were left to stand at 83°C for 16 hours, followed by a conditioning treatment of cooling in a desiccator at 23±5°C for at least 1 hour. The Vicat softening temperature (°C) of the conditioned test pieces was measured using a heat distortion tester (Yasuda Seiki Co., Ltd. "148-6-type") according to JIS K7206 (B50 method). The results are shown in Table 2.

[0183] To evaluate the optical properties of the obtained molded articles after accelerated degradation treatment, the following tests were conducted.

[0184] Test pieces of 50mm×50mm×3mm made of molded plastic sheet were subjected to accelerated degradation treatment and placed in a thermostat (VOS-301SD vacuum oven manufactured by Tokyo Rikagi K. Co., Ltd.) at 80°C for 200 hours. Using the test pieces after accelerated degradation treatment, the total light transmittance Tt (%) of light in the wavelength range of 380nm to 780nm with an optical path length of 50mm was measured. A spectrophotometer (Hitachi High Tech Fielding U-4000 spectrophotometer manufactured by Hitachi High Tech Fielding Co., Ltd.) was used for the measurement. If the total light transmittance is 81% or higher, the total light transmittance of the molded body after accelerated degradation treatment is considered good. The results are shown in Table 2.

[0185]

[0186] As shown in Table 2, the molded articles made using the compositions of Examples 1-5 had the same Vicat softening temperature as Comparative Example 1 (which did not add alcohol to methyl methacrylate), but showed a higher total transmittance after accelerated degradation treatment. Based on these results, the molded articles made using the compositions of Examples 1-5 exhibit good heat resistance and excellent optical properties even after prolonged use.

Claims

1. A composition comprising methyl methacrylate and an alcohol having four carbon atoms. The concentration of the alcohol with 4 carbon atoms is 5 ppm to 10,000 ppm by mass of the whole composition.

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

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

4. The composition according to claim 1, wherein, The concentration of the alcohol with 4 carbon atoms is 5 ppm to 6000 ppm by mass of the whole composition.

5. The composition according to claim 1, wherein, The concentration of the alcohol with 4 carbon atoms is 50 ppm to 6000 ppm by mass of the whole composition.

6. The composition according to claim 1, wherein, An alcohol with 4 carbon atoms is n-butanol.

7. The composition according to claim 1, wherein, Methyl methacrylate includes recycled methyl methacrylate or biologically derived methyl methacrylate.

8. The composition according to claim 1, wherein, It further contains (meth)acrylates other than methyl methacrylate.

9. The composition according to claim 1, wherein, It further includes polymers containing structural units derived from methyl methacrylate.

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

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

12. A cured product, which is a cured product of the composition according to any one of claims 1 to 9.

13. A molded article comprising the cured product of claim 12.

14. A method for manufacturing polymethyl methacrylate, comprising the step of polymerizing the polymethyl methacrylate contained in the composition according to any one of claims 1 to 9.

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