Resin composition excellent in transparency and molded article thereof

Abstract

[Problem] To provide a resin composition that solves the problem of reducing the use ratio of a raw material derived from petroleum resources while maintaining characteristics of transparency, heat resistance, mechanical characteristics, and moldability inherent in a resin. [Solution] The present embodiment is a resin composition excellent in transparency. This resin composition comprises: a base resin including at least one of a styrene-based resin, a polycarbonate resin, and an acrylic resin; and an acetal compound in which at least some of hydroxy groups of a monosaccharide or an oligosaccharide react with an aldehyde. The content ratio of the base resin in the resin composition is 70%-97% by mass, and the molecular weight of the acetal compound is 200-1000.

Description

Resin composition with excellent transparency and molded article thereof

[0001] The present invention relates to a resin composition having excellent transparency and a molded article made from the resin composition.

[0002] Regarding conventional biomass-derived transparent resins, supply has begun using a mass balance method via biomass naphtha. While this technology has advantages such as production using existing facilities and quality equivalent to that of fossil-derived resins, there are concerns about supply due to the difficulty of increasing the biomass content. Therefore, mixing biomass-derived resins as additives with petroleum-derived resins to provide biomass-derived resin compositions while maintaining mechanical properties and moldability has been proposed as a method to reduce environmental impact.

[0003] As an example, Patent Document 1 discloses a styrene-based resin blended with polylactic acid, which has low environmental impact and excellent impact resistance. Patent Document 2 discloses a resin composition blended with a polysaccharide derivative, which has excellent heat resistance and hardness, and Patent Document 3 discloses a styrene-based resin blended with a cellulose-based polysaccharide, which has excellent light transparency, heat resistance, and appearance. Patent Document 4 discloses a styrene-based resin blended with a biopolyester, which has excellent transparency and heat resistance, and Patent Document 5 discloses a styrene-based resin blended with a biomass-derived plasticizer, such as vegetable oil, which has excellent properties for reducing environmental impact and mold fouling.

[0004] Patent Document 6 discloses a biopolycarbonate in which polylactic acid, a biomass-derived resin, is kneaded with a general-purpose polycarbonate, and Patent Document 7 discloses a biopolycarbonate in which conventional bisphenol A is replaced with an isosorbide-modified compound derived from sugar. Patent Document 8 also discloses a technology for producing methacrylic acid and / or its esters using microorganisms.

[0005] However, Patent Documents 1 and 2 blend an incompatible resin with a styrene-based resin, making it difficult to maintain high transparency. Patent Document 3 blends a large amount of powdered cellulose, making it impossible to achieve high transparency. Patent Document 4 inevitably decomposes the polyester, making it impossible to achieve high transparency. Patent Document 5 contains rubber-like particles, making it impossible to obtain a highly transparent styrene-based resin. Furthermore, Patent Document 6 blends an incompatible resin, and Patent Document 7 introduces a biomass component into a polycarbonate resin and wood flour, making it impossible to achieve high transparency. Patent Document 8 requires highly pure acrylic resin raw material components derived from microorganisms, making it difficult and costly to produce.

[0006] JP 2015-86251 A JP 2020-132790 A JP 2021-165378 A JP 2022-134223 A JP 2023-25620 A JP 2007-191577 A JP 2012-92235 A International Publication No. 2014 / 038216

[0007] Therefore, the present invention provides a resin composition that solves the problem of reducing the proportion of petroleum-derived raw materials used while maintaining the inherent characteristics of resins, such as transparency, heat resistance, mechanical properties, and moldability.

[0008] This embodiment relates to a resin composition having excellent transparency. The resin composition includes a base resin containing at least one of a styrene-based resin, a polycarbonate resin, and an acrylic resin, and an acetal compound in which at least a portion of the hydroxyl groups of a monosaccharide or oligosaccharide has reacted with an aldehyde. The content of the base resin in the resin composition is 70% by mass or more and 97% by mass or less, and the acetal compound has a molecular weight of 200 to 1,000.

[0009] The content of the base resin in the resin composition is preferably 85% by mass or more and 95% by mass or less. The aldehydes are preferably derived from biomass. The aldehydes are at least one of anisaldehyde, cinnamaldehyde, furfural, and glyoxylic acid. Furthermore, the aldehyde is preferably cinnamaldehyde. The molded article of this embodiment uses these resin compositions with excellent transparency.

[0010] The resin composition of the present invention can maintain its characteristics of transparency, heat resistance, mechanical properties, and moldability while reducing the proportion of petroleum-derived raw materials used.

[0011] <<Configuration of Resin Composition>> The resin composition of this embodiment includes (a) a base resin containing at least one of a styrene-based resin, a polycarbonate resin, and an acrylic resin, and (b) an acetal compound in which at least a portion of the hydroxyl groups of a monosaccharide or oligosaccharide has reacted with an aldehyde. The content of the (a) base resin in the resin composition is 70% by mass or more and 97% by mass or less. If the content is less than 70% by mass, high transparency cannot be obtained, and if the content exceeds 97% by mass, a high biomass component ratio cannot be obtained. Furthermore, the content of the (a) base resin in the resin composition is preferably 80% by mass or more and 95% by mass or less, and more preferably 85% by mass or more and 90% by mass or less.

[0012] By blending an acetal compound with the (a) base resin, it is possible to obtain a resin composition that is excellent in heat resistance, mechanical properties, and moldability while maintaining transparency. Although the mechanism behind this is still unclear, the (a) base resin is a so-called amorphous polymer, and is characterized by inhibiting crystallization due to its large side chains and highly curved main chain, thereby exhibiting high transparency.

[0013] Furthermore, the acetal compound of this embodiment forms multiple cyclic acetal structures around the starting sugar at the center, resulting in a compound that is relatively bulky but has low rigidity. This characteristic is thought to result in (a) easy access to the polymer chains of the base resin and the ability to further disrupt the structure, thereby maintaining transparency even when incorporated in large amounts and exhibiting high heat resistance, mechanical properties, and moldability.

[0014] By selecting appropriate molding conditions and composition, the resin composition of this embodiment can be made into a resin composition with a total light transmittance of 80% or more and 93% or less. The preferred range of total light transmittance is 85% or more, more preferably 87% or more, and even more preferably 88% or more. If the total light transmittance is less than 80%, the target transparency cannot be achieved, and a total light transmittance of more than 93% is difficult to achieve due to the unavoidable nature of reflected light in terms of the measurement principle. The total light transmittance is a value measured in accordance with JIS K7375:2008.

[0015] By selecting appropriate molding conditions and composition, the resin composition can be made to have a haze of 0.1% or more and 10% or less. The preferred range of haze is 4% or less, more preferably 2% or less, and even more preferably 1% or less. If the haze exceeds 10%, the transparency targeted by this embodiment cannot be achieved, and a value of less than 0.1% is difficult to achieve due to the measurement principle. The haze is a value measured in accordance with JIS K7136:2000.

[0016] <<Base Resin>> <Styrene-Based Resin> The applicant will first explain the styrene-based resin that is the base resin of the resin composition. The styrene-based resin is obtained by polymerizing an aromatic vinyl compound-based monomer, and may be copolymerized with a vinyl-based monomer as needed, or may be rubber-modified by adding a conjugated diene-based rubbery polymer. The styrene-based resin can be produced by a known polymerization method, such as bulk polymerization, two-stage bulk / suspension polymerization, or solution polymerization.

[0017] Known aromatic vinyl compound monomers such as styrene, α-methylstyrene, α-methyl-p-methylstyrene, o-methylstyrene, m-methylstyrene, p-methylstyrene, vinyltoluene, ethylstyrene, isobutylstyrene, and t-butylstyrene, or bromostyrene and indene can be used. Among these, styrene is preferred as the main component. Furthermore, the above-mentioned aromatic vinyl compound monomers other than styrene, acrylonitrile, (meth)acrylic acid, methyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, butyl (meth)acrylate, cyclohexyl (meth)acrylate, and other (meth)acrylic acid esters, can be copolymerized within a range that does not impair the performance of the styrene-based resin of this embodiment. Furthermore, in this embodiment, a small amount of a crosslinking agent such as divinylbenzene may be added to the styrene-based resin and polymerized.

[0018] Conjugated diene rubbery polymers used for rubber modification of styrene resins include polybutadiene, styrene-butadiene random or block copolymers, polyisoprene, polychloroprene, styrene-isoprene random, block or graft copolymers, ethylene-propylene rubber, ethylene-propylene-diene rubber, etc. Polybutadiene and styrene-butadiene random, block or graft copolymers are particularly preferred. These may also be partially hydrogenated.

[0019] The content of the conjugated diene rubbery polymer contained in the styrene-based resin is preferably 10% by mass or less, relative to 100% by mass of the total amount of the styrene-based resin. By setting the content of the rubbery polymer to 10% by mass or less, high fluidity of the styrene-based resin can be obtained. In order to have high transparency, a content of 2% by mass or less is more preferable. From the viewpoint of impact resistance, the average particle size of the conjugated diene rubbery polymer contained in the styrene-based resin of this embodiment is preferably 0.8 μm or more and 3.5 μm or less.

[0020] Specific examples of such styrene-based resins include polystyrene (GPPS), high impact polystyrene (HIPS), ABS resin (acrylonitrile-butadiene-styrene copolymer), AS resin (acrylonitrile-styrene copolymer), MS resin (methyl methacrylate-styrene copolymer), ASA resin (acrylonitrile-styrene-acrylic acid ester copolymer), AES resin (acrylonitrile-ethylene propylene-styrene copolymer), MBS resin (methyl methacrylate-butadiene-styrene copolymer), etc.

[0021] The weight-average molecular weight of the styrene polymer is preferably 100,000 or more and 300,000 or less, more preferably 120,000 or more and 250,000 or less, and even more preferably 140,000 or more and 200,000 or less. When the weight-average molecular weight is 100,000 or more and 300,000 or less, a resin with an excellent balance between mechanical properties and fluidity can be obtained, and the amount of gel contamination is small. The weight-average molecular weight is a value obtained by gel permeation chromatography in terms of standard polystyrene.

[0022] <Polycarbonate Resin> The main component of polycarbonate resin is aromatic polycarbonate resin. Typical polycarbonate resins are obtained by reacting dihydric phenols with carbonate precursors. This reaction can be carried out by interfacial polycondensation, melt transesterification, solid-phase transesterification of carbonate prepolymers, ring-opening polymerization of cyclic carbonate compounds, etc.

[0023] Examples of dihydric phenols include hydroquinone, resorcinol, 4,4'-biphenol, 1,1-bis(4-hydroxyphenyl)ethane, 2,2-bis(4-hydroxyphenyl)propane (common name: bisphenol A), 2,2-bis(4-hydroxy-3-methylphenyl)propane, 2,2-bis(4-hydroxyphenyl)butane, 1,1-bis(4-hydroxyphenyl)-1-phenylethane, 1,1-bis(4-hydroxyphenyl)cyclohexane, 1,1-bis(4-hydroxyphenyl)-3,3,5-trimethylcyclohexane, 2,2-bis(4-hydroxyphenyl)pentane, 4,4'-(p-phenylenediisopropylidene)diphenol, and 4,4'-(m-phenylenediisopropylidene)diphenol. bis(4-hydroxyphenyl)propane, 1,1-bis(4-hydroxyphenyl)-4-isopropylcyclohexane, bis(4-hydroxyphenyl)oxide, bis(4-hydroxyphenyl)sulfide, bis(4-hydroxyphenyl)sulfoxide, bis(4-hydroxyphenyl)sulfone, bis(4-hydroxyphenyl)ketone, bis(4-hydroxyphenyl)ester, 2,2-bis(3,5-dibromo-4-hydroxyphenyl)propane, bis(3,5-dibromo-4-hydroxyphenyl)sulfone, bis(4-hydroxy-3-methylphenyl)sulfide, 9,9-bis(4-hydroxyphenyl)fluorene, 9,9-bis(4-hydroxy-3-methylphenyl)fluorene, and the like, including isosorbide, isomannide, isoidide, and the like. Examples of cyclic dihydroxy compounds include 3,9-bis(1,1-dimethyl-2-hydroxyethyl)-2,4,8,10-tetraoxaspiro(5.5)undecane (common name: spiroglycol), 3,9-bis(1,1-diethyl-2-hydroxyethyl)-2,4,8,10-tetraoxaspiro(5.5)undecane, 3,9-bis(1,1-dipropyl-2-hydroxyethyl)-2,4,8,10-tetraoxaspiro(5.5)undecane, etc. Among these, bis(4-hydroxyphenyl)alkanes, particularly bisphenol A, are preferred.Furthermore, cyclic anhydrosugar alcohols, particularly isosorbide, which can be produced from sugars as biomass-derived raw materials, can be produced inexpensively by hydrogenating or dehydrating D-glucose obtained from starch.

[0024] Polycarbonates prepared by polymerizing at least one of 4,4'-(m-phenylenediisopropylidene)diphenol, 1,1-bis(4-hydroxyphenyl)cyclohexane, 1,1-bis(4-hydroxyphenyl)-3,3,5-trimethylcyclohexane, 9,9-bis(4-hydroxyphenyl)fluorene, and 9,9-bis(4-hydroxy-3-methylphenyl)fluorene as part or all of the dihydric phenol component are suitable for applications requiring particularly strict resistance to dimensional change due to water absorption and dimensional stability. In such cases, the dihydric phenol other than bisphenol A is preferably used in an amount of 5 mol % or more, and more preferably 10 mol % or more, of the total dihydric phenol components constituting the polycarbonate.

[0025] A small amount of polyhydric phenol components such as 1,1,1-tris(4-hydroxyphenyl)ethane and 1,1,1-tris(3,5-dimethyl-4-hydroxyphenyl)ethane can also be used.

[0026] Among polycarbonate resins, those having a water absorption of 0.05% by mass or more and 0.15% by mass or less and a glass transition temperature of 120°C or more and 250°C or less, which are obtained by adjusting the copolymer composition or the like, have good hydrolysis resistance of the polymer itself and excellent low warpage after molding, and are therefore particularly suitable in fields where dimensional stability is required.

[0027] Carbonyl halides, carbonate esters, dihaloformates, etc. are used as carbonate precursors. Specific examples include phosgene, diphenyl carbonate, ditolyl carbonate, bis(chlorophenyl) carbonate, m-cresyl carbonate, dinaphthyl carbonate, bis(biphenyl) carbonate, diethyl carbonate, dimethyl carbonate, dibutyl carbonate, and dicyclohexyl carbonate. Diphenyl carbonate is particularly preferred.

[0028] The polycarbonate resin may contain, as needed, a catalyst, a terminal blocking agent, an antioxidant for preventing oxidation of the dihydric phenol, etc., together with the dihydric phenol and carbonate precursor described above. The polycarbonate resin is produced by a known production method such as interfacial polymerization or melt transesterification polymerization, solid-phase transesterification of carbonate prepolymer, or ring-opening polymerization of a cyclic carbonate compound.

[0029] The polycarbonate resin may be a polyester carbonate copolymerized with an aromatic or aliphatic (including alicyclic) bifunctional carboxylic acid, a copolymer polycarbonate copolymerized with a bifunctional alcohol (including alicyclic), or a polyester carbonate copolymerized with both such a bifunctional carboxylic acid and a bifunctional alcohol. A blend of two or more of the resulting polycarbonates may also be used. Polycarbonate resins may be waste materials from manufacturing or product processing, or recycled materials after product use.

[0030] The aliphatic bifunctional carboxylic acid is preferably an α,ω-dicarboxylic acid. Examples of the aliphatic bifunctional carboxylic acid include straight-chain saturated aliphatic dicarboxylic acids such as sebacic acid (decanedioic acid), dodecanedioic acid, tetradecanedioic acid, octadecanedioic acid, and eicosanedioic acid, and alicyclic dicarboxylic acids such as cyclohexanedicarboxylic acid. The bifunctional alcohol is more preferably an alicyclic diol, such as cyclohexanedimethanol, cyclohexanediol, and tricyclodecanedimethanol.

[0031] Furthermore, the polycarbonate resin may be a polycarbonate-polyorganosiloxane copolymer obtained by copolymerizing polyorganosiloxane units.

[0032] Although the viscosity average molecular weight of the polycarbonate resin is not limited, it is preferably in the range of 11,000 to 35,000. By setting it to 11,000 or more, sufficient strength can be obtained, and by setting it to 35,000 or less, good molding processability can be achieved. In this sense, the viscosity average molecular weight is more preferably in the range of 15,000 to 25,000.

[0033] <Acrylic Resin> The main component of the acrylic resin of the base resin of this embodiment is a repeating unit derived from methyl methacrylate, and it is preferable that the repeating unit accounts for 85% by mass or more and 99% by mass or less of 100% by mass of the acrylic resin. When the repeating unit derived from methyl methacrylate accounts for 85% by mass or more, the acrylic resin has excellent mechanical properties and heat resistance, and when the repeating unit accounts for 99% by mass or less, the acrylic resin has excellent thermal stability.

[0034] Examples of alkyl acrylates include methyl acrylate, ethyl acrylate, n-propyl acrylate, isopropyl acrylate, n-butyl acrylate, isobutyl acrylate, sec-butyl acrylate, tert-butyl acrylate, n-hexyl acrylate, cyclohexyl acrylate, n-octyl acrylate, and 2-ethylhexyl acrylate. These alkyl acrylates may be used alone or in combination of two or more. Among these alkyl acrylates, methyl acrylate and ethyl acrylate are preferred, with methyl acrylate being more preferred, as they can reduce the production cost of the acrylic resin.

[0035] Furthermore, the acrylic resin may be copolymerized with repeating units other than methyl methacrylate and alkyl acrylate, as long as the inherent performance of the acrylic resin is not impaired. Copolymerizable monomers include (meth)acrylate compounds, (meth)acrylamide compounds, aromatic vinyl compounds, vinyl ether compounds, vinyl carboxylate compounds, olefin compounds, etc. These monomers may be used alone or in combination of two or more.

[0036] Examples of the (meth)acrylate compound include ethyl methacrylate, n-propyl methacrylate, iso-propyl methacrylate, n-butyl methacrylate, iso-butyl methacrylate, sec-butyl methacrylate, tert-butyl methacrylate, n-hexyl methacrylate, cyclohexyl methacrylate, n-octyl methacrylate, 2-ethylhexyl methacrylate, phenyl (meth)acrylate, bornyl (meth)acrylate, norbornyl (meth)acrylate, isobornyl (meth)acrylate, adamantyl (meth)acrylate, and glycidyl (meth)acrylate. Examples of (meth)acrylamide compounds include (meth)acrylic acid, (meth)acrylonitrile, (meth)acrylamide, N-dimethyl(meth)acrylamide, N-diethyl(meth)acrylamide, N-butyl(meth)acrylamide, dimethylaminopropyl(meth)acrylamide, N-methylol(meth)acrylamide, N-methoxymethyl(meth)acrylamide, N-butoxymethyl(meth)acrylamide, hydroxyethyl(meth)acrylamide, methylenebis(meth)acrylamide, etc. Examples of aromatic vinyl compounds include styrene and α-methylstyrene, examples of vinyl ether compounds include methyl vinyl ether, ethyl vinyl ether, 2-hydroxyethyl vinyl ether, etc., examples of vinyl carboxylate compounds include vinyl acetate and vinyl butyrate, and examples of olefin compounds include ethylene, propylene, butene, isobutene, etc.

[0037] Examples of polymerization methods for acrylic resins include bulk polymerization, solution polymerization, suspension polymerization, emulsion polymerization, etc. Among these polymerization methods, bulk polymerization, solution polymerization, and suspension polymerization are preferred because they do not require an emulsifier and provide excellent optical properties to the acrylic resin, with bulk polymerization being more preferred, and continuous bulk polymerization being even more preferred because it is highly productive and can suppress contamination with foreign matter.

[0038] In either polymerization, a small amount of a polymerization initiator is used to initiate the polymerization, and examples of the polymerization initiator include organic peroxides and azo compounds. Examples of organic peroxides include tert-butylperoxy-3,5,5-trimethylhexanate, tert-butylperoxylaurate, tert-butylperoxyisopropyl monocarbonate, tert-hexylperoxyisopropyl monocarbonate, tert-butylperoxyacetate, 1,1-bis(tert-butylperoxy)3,3,5-trimethylcyclohexane, 1,1-bis(tert-butylperoxy)cyclohexane, tert-butylperoxy2-ethylhexanate, tert-butylperoxyisobutyrate, tert-hexylperoxy2-ethylhexanate, di-tert-butyl peroxide, di-tert-hexyl peroxide, and 2,5-dimethyl-2,5-bis(tert-butylperoxy)hexane. Examples of azo compounds include 2-(carbamoylazo)-isobutyronitrile, 1,1'-azobis(1-cyclohexanecarbonitrile), 2,2'-azobisisobutyronitrile, 2,2'-azobis(2-methylbutyronitrile), dimethyl 2,2'-azobisisobutyrate, 2,2'-azobis(2,4,4-trimethylpentane), and 2,2'-azobis(2-methylpropane). These polymerization initiators may be used alone or in combination of two or more. Among these polymerization initiators, organic peroxides are preferred because they can reduce production costs, and tert-butylperoxy-3,5,5-trimethylhexanate and di-tert-butyl peroxide are more preferred.

[0039] The amount of the polymerization initiator used is preferably 0.001% by mass or more and 1% by mass or less, and more preferably 0.005% by mass or more and 0.1% by mass or less, relative to 100% by mass of the total monomers, since the desired mass average molecular weight can be obtained. When the amount of the polymerization initiator used is 0.001% by mass or more, the polymerization rate of the monomers is excellent. Furthermore, when the amount of the polymerization initiator used is 1% by mass or less, the production cost can be reduced.

[0040] It is also desirable to use a chain transfer agent in the polymerization reaction system to control the molecular weight and molecular weight distribution. Examples of the chain transfer agent include mercaptan compounds. These chain transfer agents may be used alone or in combination of two or more. Among these chain transfer agents, mercaptan compounds are preferred because they can reduce production costs.

[0041] Examples of mercaptan compounds include primary, secondary, and tertiary mercaptans having an alkyl group or a substituted alkyl group, such as n-butyl, iso-butyl, sec-butyl, tert-butyl, n-octyl, n-dodecyl, and sec-dodecyl; aromatic mercaptans such as phenyl mercaptan, thiocresol, and 4-tert-butyl-o-thiocresol; and mercaptans having 2 to 18 carbon atoms, such as thioglycolic acid and its esters and ethylene thioglycol. These mercaptan compounds may be used alone or in combination of two or more. Among these mercaptan compounds, n-butyl mercaptan, tert-butyl mercaptan, n-octyl mercaptan, and n-dodecyl mercaptan are preferred because they can reduce production costs, and n-butyl mercaptan and n-octyl mercaptan are more preferred.

[0042] The amount of chain transfer agent used is preferably 0.01% by mass or more and 2% by mass or less, and more preferably 0.05% by mass or more and 1% by mass or less, relative to 100% by mass of all monomers, since the desired mass average molecular weight can be obtained. When the amount of chain transfer agent used is 0.01% by mass or more, the polymerization stability of the monomers is excellent. Furthermore, when the amount of chain transfer agent used is 2% by mass or less, the production cost can be reduced.

[0043] The weight-average molecular weight of the acrylic resin is preferably 30,000 or more and 70,000 or less. When the weight-average molecular weight of the acrylic resin is 30,000 or more, the mechanical properties of the acrylic resin are excellent, and when it is 70,000 or less, the formability of the acrylic resin is excellent. The molecular weight distribution of the acrylic resin is preferably 2.0 or more and 4.0 or less, and more preferably 2.4 or more and 3.6 or less. When the molecular weight distribution of the acrylic resin is 2.0 or more, the formability of the acrylic resin is excellent, and when it is 4.0 or less, the flow stability of the acrylic resin is excellent.

[0044] <<Acetal Compounds>> Acetal compounds are compounds in which at least a portion of the hydroxyl groups of a monosaccharide or oligosaccharide have reacted with aldehydes. Here, monosaccharides refer to sugars that are not further hydrolyzed. Examples of monosaccharides include, but are not limited to, pentoses such as xylose and arabinose, and hexoses such as glucose, mannose, galactose, and fructose. Furthermore, here, oligosaccharides refer to sugars in which two or more but not more than ten monosaccharides are linked by glycosidic bonds. However, small amounts of monosaccharides or polysaccharides in which more than 10 sugars are linked may also be contained.

[0045] As an example of the structure of the acetal compound of this embodiment, the structure of a sugar derivative obtained by reacting xylose, a pentose, with an aldehyde R1-CHO is shown in Formula 1. In this way, an acetal structure is obtained in which the aldehydes react with the hydroxyl groups at the 1st, 2nd, 3rd, and 4th positions of xylose, respectively, and a compound with relatively high bulkiness but low rigidity is obtained. (Formula 1)

[0046] In the case of hexoses or oligosaccharides, two adjacent hydroxyl groups of the sugar react with an aldehyde to produce an acetal compound. In the case of monosaccharides, the number of acetal structures is one or two, while in the case of oligosaccharides, the number of acetal structures is approximately equal to the number of monosaccharides.

[0047] The molecular weight of the acetal compound is 200 or more and 1000 or less, and this characteristic is fully exhibited. With an acetal structure having a molecular weight of less than 200, the above-mentioned characteristics of the sugar derivative cannot be obtained, and if the molecular weight exceeds 1000, the mobility of the sugar derivative (b) decreases. The molecular weight is preferably 300 or more and 600 or less.

[0048] The aldehydes have at least two carbon atoms and at least one aldehyde group (—CHO), such as saturated or unsaturated alkyl aldehydes, cyclic aldehydes, glyoxylic acid, or alkyl glyoxylates.

[0049] The saturated alkyl aldehyde, when linear, is a fully saturated compound having a chain length of C2-C20, preferably C2-C14, selected from, for example, acetaldehyde, propionaldehyde, butyraldehyde, pentanal (valeraldehyde), hexanal, heptanal, octanal, nonanal, decanal, undecanal, dodecanal, tridecanal, tetradecanal (myristaldehyde), etc. When branched, it is a fully saturated compound having a maximum main chain length of C8, particularly C3-C8, and when the branched chain is an alkyl group, it is selected from, for example, isobutyraldehyde, isovaleraldehyde, 2-methylbutyraldehyde, 3,5,5-trimethylhexanal, trimethylacetaldehyde, 6-methoxy-2,6-dimethyloctanal, etc.

[0050] The linear unsaturated alkyl aldehyde is selected from compounds having one or more degrees of unsaturation such that the chain length is C3-C20, preferably C3-C8, for example, 2-propenal (acrolein), 2-butenal (crotonaldehyde), 3-butenal, trans-2-hexenal, cis-3-hexenal, 2-heptenal, 3-heptenal, 5-heptenal, 2-octenal, 9-decenal, having one degree of unsaturation, and 2,4-pentadienal, 2,4-hexadienal, 2,4-heptadienal, 3,5-heptadienal, (cis or trans) 2,4-octadienal, etc., having two or more degrees of unsaturation. The branched unsaturated alkyl aldehyde is selected from 2-methyl-2-butenal (tiglinaldehyde), 2,6-dimethyl-5-heptenal (melonal), 2-methyl-2-pentenal, 2,6,10-trimethyl-9-undecenal (adoxal), and the like.

[0051] The unsaturated alkyl aldehyde may have any substituent, and the substituent may be selected from citral (lemonal, geranial, neral), citronellal, cinnamaldehyde, α-methyl cinnamaldehyde, α-hexyl cinnamaldehyde, α-amyl cinnamaldehyde (jasmine aldehyde), β-phenyl cinnamaldehyde, 2-hydroxy cinnamaldehyde, 4-hydroxy cinnamaldehyde (coumaraldehyde), 2-methoxy cinnamaldehyde, 3,5-dimethoxy-4-hydroxy cinnamaldehyde (sinapaldehyde), 4-acetoxy-3-methoxy cinnamaldehyde, 4-hydroxy-3-methoxy cinnamaldehyde (coniferyl aldehyde), 4-chloro cinnamaldehyde, 4-bromo cinnamaldehyde, 4-fluoro cinnamaldehyde, 2,6-difluoro cinnamaldehyde, and the like.

[0052] Cyclic aldehydes are compounds of the carbaldehyde class, i.e., compounds in which the aldehyde group is directly bonded to a ring. The ring may be a monocyclic ring containing 3 to 8 carbon atoms. More specifically, it may be a non-aromatic, aromatic, or aromatic heterocyclic ring. These may be unsubstituted or substituted.

[0053] Non-aromatic cyclic aldehydes include cyclopropanecarbaldehyde, cyclobutanecarbaldehyde, cyclopentanecarbaldehyde, cyclohexanecarbaldehyde, cycloheptanecarbaldehyde, cyclooctanecarbaldehyde, etc. These non-aromatic cyclic aldehydes may have a substituent, and may be selected from perillaldehyde, etc.

[0054] The aromatic cyclic aldehyde is benzaldehyde, 1-naphthaldehyde, 2-naphthaldehyde, etc., and the substituent is selected from a C1-C8 alkyl group, an ether group, a hydroxy group, etc., and the substituent may be the same or different, or multiple types of substituents.

[0055] Benzaldehydes substituted with a C1-C8 alkyl group include 2-methylbenzaldehyde, 3-methylbenzaldehyde, 4-methylbenzaldehyde (the o-, m-, and p-isomers of tolualdehyde, respectively), 2,4-dimethylbenzaldehyde, 2,5-dimethylbenzaldehyde, 2,6-dimethylbenzaldehyde, 2,4,6-trimethylbenzaldehyde (mesitaldehyde), 4-ethylbenzaldehyde, 2-ethylbenzaldehyde, biphenyl-2-carboxaldehyde, biphenyl-3-carboxaldehyde, biphenyl-4-carboxaldehyde, 4-tertbutylbenzaldehyde, 2,5-di-tertbutyl-benzaldehyde, and 4-isopropylbenzaldehyde (cuminaldehyde).

[0056] Hydroxy-substituted benzaldehydes include 2-hydroxybenzaldehyde (salicylaldehyde), 3-hydroxybenzaldehyde, 4-hydroxybenzaldehyde, 2,3-dihydroxybenzaldehyde, 2,4-dihydroxybenzaldehyde, 2,5-dihydroxybenzaldehyde (gentisaldehyde), 3,4-dihydroxybenzaldehyde (protocatechuic aldehyde), 2,3,4-trihydroxybenzaldehyde, 2,4,5-trihydroxybenzaldehyde, 2,4,6-trihydroxybenzaldehyde (phloroglucinaldehyde), and the like.

[0057] Benzaldehydes may have different substituents, such as 2-hydroxy-3-methoxybenzaldehyde, 2-hydroxy-4-methoxybenzaldehyde, 3-hydroxy-4-methoxybenzaldehyde (isovanillin), 4-hydroxy-2-methoxybenzaldehyde, 4-hydroxy-3-methoxybenzaldehyde (vanillin), heliotropin (piperonal), 2,6-dimethoxy-4-hydroxybenzaldehyde, 3,4-dimethoxy-5-hydroxybenzaldehyde. Benzaldehyde, 3,5-dimethoxy-4-hydroxybenzaldehyde (syringaldehyde), 4-ethoxy-3-methoxybenzaldehyde, 3-ethoxy-4-methoxybenzaldehyde, 3-ethoxy-4-hydroxybenzaldehyde (ethyl vanillin), 2-ethoxy-3-methoxybenzaldehyde, 2-benzyloxy-3-methoxybenzaldehyde, 3-benzyloxy-4-methoxybenzaldehyde, 4-benzyloxy-3-methoxybenzaldehyde, and the like.

[0058] The cyclic aldehyde may be a heterocyclic aromatic aldehyde, including furfural, 2-pyridinecarboxaldehyde, 3-pyridinecarboxaldehyde, 4-pyridinecarboxaldehyde, 2-thiazolecarboxaldehyde, pyrrole-2-carboxaldehyde, 3-thiophenecarboxaldehyde, and indole-3-carboxaldehyde. The heterocyclic aromatic aldehyde may further have a substituent, including 3-methyl-2-thiophenecarboxaldehyde, 6-methylpyridinecarboxaldehyde, N-benzylpyridine-4-carboxaldehyde, and 1-methylimidazolecarboxaldehyde.

[0059] The aldehydes of this embodiment may have two or more aldehyde groups and may further have a substituent. Specific examples include glyoxal, 2-methylmalonaldehyde, succinaldehyde, glutaraldehyde, bromomalonaldehyde, terephthalaldehyde, o-phthalaldehyde, m-phthalaldehyde, bis(4-formylphenyl)ether, bis(2-formylphenyl)ether, 4,4′-biphenyldicarboxaldehyde, and tris(4-formylphenyl)amine.

[0060] The aldehydes are preferably derived from biomass. "Biomass-derived" means that the carbon atoms constituting the aldehyde are derived from biomass, and includes those extracted and purified from natural products, as well as those chemically synthesized using natural products as raw materials. In this embodiment, the ratio of carbon atoms derived from biomass can be determined from the abundance ratio of 14C in the total carbon measured in accordance with ASTM D6866. In this embodiment, the ratio of carbon atoms derived from biomass in the sugar derivative (b) determined by this measurement is preferably 50% or more, more preferably 90% by mass or more, and even more preferably 100%.

[0061] Examples of such biomass-derived aldehydes include glyoxylic acid, glyoxylic acid alkyl esters, pentanal (valeraldehyde), hexanal, heptanal, nonanal, decanal, undecanal, dodecanal, tridecanal, tetradecanal (myristaldehyde), isovaleraldehyde, phenylacetaldehyde, 7-hydroxy-3,7-dimethyl-octanal (hydroxycitronellal), D-glyceraldehyde, D-erythrose, trans-2-hexenal, cis-3-hexenal, citral (lemonal, geranial, neral), citronellal, cinnamaldehyde, α-hexylcinnamaldehyde, 4-hydroxycinnamaldehyde (coumaraldehyde), 3,5-dimethyl- These include 4-hydroxy-4-hydroxycinnamaldehyde (sinapaldehyde), 4-hydroxy-3-methoxycinnamaldehyde (coniferyl aldehyde), perillaldehyde, 4-isopropylbenzaldehyde (cuminaldehyde), 4-methoxybenzaldehyde (anisaldehyde), 3,4,5-trimethoxybenzaldehyde, 4-hydroxybenzaldehyde, 3,4-dihydroxybenzaldehyde (protocatechuic aldehyde), 2,3,4-trihydroxybenzaldehyde, 2-hydroxy-4-methoxybenzaldehyde, 4-hydroxy-3-methoxybenzaldehyde (vanillin), heliotropin (piperonal), 3,5-dimethoxy-4-hydroxybenzaldehyde (syringaldehyde), and furfural.

[0062] Among these aldehydes, anisaldehyde, cinnamaldehyde, furfural, and glyoxylic acid are preferred because they provide excellent transparency, heat resistance, mechanical properties, and moldability as the resin composition of this embodiment, and among these, cinnamaldehyde is more preferred. These four types of aldehydes are widely used as raw materials for industrial products, and therefore biomass-derived products are easily available.

[0063] The content of the acetal compound in the resin composition is 3% by mass or more and 30% by mass or less. If it is less than 3% by mass, a high biomass component ratio cannot be obtained, and if it exceeds 30% by mass, high transparency cannot be obtained. The content of the acetal compound in the resin composition is preferably 5% by mass or more and 20% by mass or less, and more preferably 10% by mass or more and 15% by mass or less.

[0064] <<Production Method>> <Production Method of Acetal Compound> An example of a production method of an acetal compound of this embodiment is shown below. The raw material sugar is dissolved in a highly polar solvent such as dimethylformamide (DMF) or dimethyl sulfoxide (DMSO), and 2 to 5 equivalents of an aldehyde per monosaccharide are added. An appropriate amount of an acid, for example, hydrochloric acid, sulfuric acid, citric acid, or p-toluenesulfonic acid, is added as a catalyst. The mixture is heated and stirred under reduced pressure, and then separated into methylene chloride and an aqueous sodium hydroxide solution, and the organic layer is reprecipitated with hexane in an ice bath. The crystals are then collected by suction filtration, dissolved in methylene chloride or ethyl acetate, and the solution is reprecipitated with methanol. The acetal compound is obtained by washing through repeated filtration, cooling, and reprecipitation.

[0065] <Method for producing resin composition> The resin composition is produced, for example, by weighing (a) base resin, (b) acetal compound, and optionally a third component in a predetermined ratio and melt-kneading them under heating. It is preferable that each phase of (a) base resin and (b) acetal compound is dispersed to a size sufficiently smaller than the wavelength of visible light so as to improve transparency. Whether or not the particles are dispersed to a size sufficiently smaller than the wavelength of visible light can be determined by visually observing the optical uniformity of the molded article and measuring the total light transmittance and haze.

[0066] The melt-kneading of (a) the base resin and (b) the acetal compound can be carried out, for example, by a method using a single-screw extruder, a twin-screw kneading extruder, a multi-screw kneading extruder, etc. The kneading temperature is usually selected appropriately from the range of 100°C or higher and 300°C or lower, preferably from the range of 150°C or higher and 250°C or lower, and more preferably from the range of 180°C or higher and 230°C or lower. Prior to melt-kneading, the (a) base resin, (b) the acetal compound, and, if necessary, a third component may be premixed in the form of powder or pellets by a conventional method.

[0067] The resin composition may contain a third component, if necessary, within the scope of the present embodiment. Examples of such a third component include additives conventionally used in plastics, such as plasticizers, dispersants, antioxidants, antibacterial agents, compatibilizers, lubricants, processing aids, mold release agents, stabilizers, flame retardants, transparency improvers, anti-yellowing agents, UV absorbers, antistatic agents, anti-fogging agents, pigments, dyes, and fluorescent dyes.

[0068] The resin composition may be in the form of a block, plate, film, sheet, thread, string, pellet, powder, particle, or other molded product. From the viewpoint of storage, distribution, etc., the form is preferably pellet. The shape of the pellet may be any of a cylinder, an elliptical cylinder, a plate, a sphere, an ellipsoid, etc., and examples thereof include a cylinder having a diameter of 0.5 mm or more and 5 mm or less and a length of 0.5 mm or more and 10 mm or less.

[0069] <Method for manufacturing molded article> The resin composition having excellent transparency according to this embodiment is preferably used to produce a molded article containing the resin composition at least in part. Since the resin composition according to this embodiment is thermoplastic, it can be processed into a molded article of a desired shape by heating it to melt or fluidize it, soften it, and then pouring it into a mold, compressing it, or extruding it. The melting and molding temperature is usually 200°C or higher and 230°C or lower, but this is not a limitation. The MFR value was used as an index of moldability. The MFR in Table 1 was measured in accordance with JIS K7210-1:2014.

[0070] Examples of molding methods for molded articles include injection molding, extrusion molding, cast molding (casting), calendar molding, slush molding, blow molding, vacuum molding, powder molding, foam molding, extrusion lamination molding, T-die molding, air-cooled inflation molding, water-cooled inflation molding, and microwave molding, a type of photomolding in which a mold is heated by radiation. In some cases, molded articles may be formed by deforming (molding) using the material's own weight without using a mold, or by applying an external force using a tool. Molded articles can be molded into various shapes, such as films, sheets, thin plates, thick plates, corrugated plates, threads, filaments, rods, pipes, columns, shaped objects, and works of art.

[0071] Furthermore, since the resin composition of the present embodiment has excellent performance in heat resistance, mechanical properties, and moldability, molded articles thereof can be widely used in windows such as windows for separating the interior and exterior of transparent buildings and vehicles or rooms, partition boards, aquariums, and carport tops; covers such as lighting fixtures, flat panel displays, mobile phones, automobile headlight covers, signs, showcases, and watch covers; lenses such as lighting lenses, optical lenses, eyeglasses, and sunglasses; sheets such as blisters and carrier tapes; packaging for agricultural products; films for window coverings for paper containers and envelopes; and other daily necessities and decorative items such as ceiling materials, ballpoint pens, and cups.

[0072] <Synthesis of Acetal Compounds> The synthesis of the acetal compounds of Examples 1 to 10 will be described. A predetermined amount of raw sugar (xylose or xylooligosaccharide) was dissolved in a dimethylformamide (DMF) solution, and 2 to 5 equivalents of aldehydes per monosaccharide were added. An appropriate amount of p-toluenesulfonic acid was added to the DMF solution as a catalyst. The solution was heated and stirred at 40 to 60°C under reduced pressure for 4 hours or more, and then separated into methylene chloride and a 2 wt% aqueous sodium hydroxide solution. The organic layer was reprecipitated with hexane.

[0073] After crystallization, pale yellow crystals were extracted by filtration, dissolved in methylene chloride or ethyl acetate, and the solution was reprecipitated with methanol. The crystals were then washed by repeating the filtration, dissolution, and reprecipitation process three times. They were then dried in a vacuum dryer at 60°C for 12 hours or more to obtain a white aldehyde sugar derivative.

[0074] <Production of Resin Composition> A sugar derivative was mixed with a predetermined transparent resin to a predetermined mass ratio, and the mixture was thoroughly mixed using a blender or the like. The mixture was then kneaded at 180-230°C using a twin-screw extruder (TECHNOVEL KZW25TW-45MG-NH300), and the filaments were cut using a pelletizer to obtain pellets of the resin composition. The pellets in Examples 1-10 and Comparative Examples 1-2 were cylindrical, measuring 2-5 mm in diameter and 5-7 mm in length.

[0075] <Preparation of test pieces for evaluating physical properties> Pellets of the resin composition were molded at 210°C in a small molding machine (Epson Techform C Mobile-0813) into 40 mm x 40 mm x 1 mm flat plates, 80 mm x 10 mm x t2 mm strip test pieces, and 5A size dumbbells, and these were evaluated. It is preferable that the surface of the mold for the test pieces be mirror-polished using abrasive paper, fixed abrasive grains, free abrasive grains, or the like, as appropriate. The injection molding machine was thoroughly cleaned.

[0076] <Measurement and evaluation methods> (1) Molecular weight of acetal compound When the raw sugar was xylose, the molecular weight of the structure in which an aldehyde reacted with the hydroxyl group of xylose was taken as the molecular weight of the sugar derivative. When the raw sugar was xylooligosaccharide, the absolute molecular weight was determined by GPC-MALS-RI using the apparatus described below.

[0077] System: ACQUITY Arc Empower 3 (manufactured by Nihon Waters) Detector: (MALS) DAWN (manufactured by Wyatt Technology) (RI) 2414 RI (manufactured by Nihon Waters) Column: KF-804L (8 mm I.D. x 30 cm) x 2 (manufactured by Shodex) Eluent: THF (tetrahydrofuran) Measurement temperature: 40°C Flow rate: 0.7 mL / min Sample concentration: 1 mg / mL Injection volume: 50 μL

[0078] (2) Total light transmittance: Measured in accordance with JIS K7375:2008 using a 1 mm thick test piece and a turbidity meter manufactured by Nippon Denshoku Industries Co., Ltd. (3) Haze: Measured in accordance with JIS K7136:2000 using a 1 mm thick test piece and a turbidity meter manufactured by Nippon Denshoku Industries Co., Ltd.

[0079] (4) Tensile Test In accordance with JIS K7161-2:2014, the tensile modulus (maximum value, MPa) and breaking strain (elongation at break, %) were measured using the following test specimen and measuring device. Test specimen: Type 5A (small test specimen) Measuring device: Instron universal material testing machine Model 5966 Test speed: 2.5 mm / min Chuck distance: 50 mm (5) Flexural modulus In accordance with JIS K7171:2016, the flexural modulus was measured using the following test specimen and measuring device. Test specimen: 80 mm x 10 mm x t2 mm Measuring device: Instron universal material testing machine Model 5966 Test speed: 1 mm / min Support distance: 32 mm

[0080] (6) Deflection temperature under load The deflection temperature under load was measured in accordance with JIS K7191-2015 using the following test piece and measuring device. Test piece: 80 mm x 10 mm x t2 mm Measuring device: Heat distortion tester 148-HD-PC manufactured by Yasuda Seiki Seisakusho Co., Ltd. Bending stress: 1.80 MPa (A method) Distance between supports: 64 mm Heat rise rate: 120°C / hr Heat medium: silicone oil (7) MFR (Melt flow rate) The MFR was measured in accordance with JIS K7210-1:2014 using the following measuring device. Measuring device: Melt indexer LMFI5500 (manufactured by Nippon Dynisco Co., Ltd.) Temperature / load: 200°C, 5 kg (PS), 230°C, 2.16 kg (PMMA, PC)

[0081] The physical properties of the compositions corresponding to Examples 1 to 10 are shown in Table 1. In addition, the physical properties corresponding to Comparative Examples 1 to 4 and the physical properties of a styrene-based resin (PSJ-Polystyrene GPPS (grade name: HF77) manufactured by PS Japan Co., Ltd.), a polycarbonate resin (Panlite (registered trademark) (grade name AD-5503) manufactured by Teijin Limited), and an acrylic resin (ACRYPET (registered trademark) (grade name TF-9) manufactured by Mitsubishi Chemical Corporation) are shown in Table 2.

[0082]

[0083]

[0084] Example 1 The resin composition of Example 1 had a styrene-based resin as the base resin, accounting for 90% by mass of the composition, and the acetal compound was prepared by reacting xylose, a sugar raw material, with cinnamaldehyde (derived from biomass). The molecular weight of the acetal compound was 378. When compared with the properties of a styrene-based resin (HF77) (Table 2), as shown in Table 1, it was found that the physical properties were almost the same (although the MFR was higher).

[0085] Example 2 The resin composition of Example 2 had a styrene-based resin as the base resin, accounting for 90% by mass of the composition, and the acetal compound was prepared by reacting xylose, a sugar raw material, with acrolein (non-biomass). The molecular weight of the acetal compound was 226. Its physical properties were nearly the same as those of a styrene-based resin (HF77) (although the MFR was larger), and it was found to be similar to the physical properties of the resin composition of Example 1.

[0086] Example 3 The resin composition of Example 3 had a styrene-based resin as the base resin, accounting for 90% by mass of the composition, and the acetal compound was prepared by reacting xylose, a sugar raw material, with furfural (derived from biomass). The molecular weight of the acetal compound was 306. Its physical properties were nearly the same as those of a styrene-based resin (HF77) (although the MFR was larger), and it was found to be similar to the physical properties of the resin compositions of Examples 1 and 2.

[0087] Example 4 The resin composition of Example 4 had a styrene-based resin as the base resin, accounting for 90% by mass of the composition, and the acetal compound was prepared by reacting xylose as the raw sugar with glyoxylic acid (derived from biomass). The molecular weight of the acetal compound was 262. Its physical properties were nearly the same as those of a styrene-based resin (HF77) (although the MFR was larger), and it was found to be similar to the physical properties of the resin compositions of Examples 1 to 3.

[0088] Example 5 The resin composition of Example 5 had a styrene-based resin as the base resin, accounting for 90% by mass of the composition, and the acetal compound was prepared by reacting xylose, a sugar raw material, with anisaldehyde (derived from biomass). The molecular weight of the acetal compound was 386. Its physical properties were nearly the same as those of a styrene-based resin (HF77) (although the MFR was larger), and it was found to be similar to the physical properties of the resin compositions of Examples 1 to 4.

[0089] Example 6 The resin composition of Example 6 had a styrene-based resin as the base resin, accounting for 90% by mass of the composition, and the acetal compound was prepared by reacting xylose as the raw sugar with 3,4,5-trimethoxybenzaldehyde (derived from biomass). The molecular weight of the acetal compound was 506. Its physical properties were nearly the same as those of a styrene-based resin (HF77) (although the MFR was larger), and it was found to be similar to the physical properties of the resin compositions of Examples 1 to 5.

[0090] Example 7 The resin composition of Example 7 had a styrene-based resin as the base resin, accounting for 90% by mass of the composition, and the acetal compound was prepared by reacting xylooligosaccharide as the raw sugar with cinnamaldehyde. The molecular weight of the acetal compound was 897. Its physical properties were nearly identical to those of a styrene-based resin (HF77) (although the MFR was larger), and were also nearly similar to those of the resin composition of Example 1, which used a different raw sugar.

[0091] Example 8 In the resin composition of Example 8, the base resin was an acrylic resin (TF-9) which accounted for 90% by mass of the composition, and the acetal compound was prepared by reacting xylose, a sugar raw material, with cinnamaldehyde. The molecular weight of the acetal compound was 378. The physical properties of the resin composition of Example 8 were found to be almost the same as those of the acrylic resin (TF-9) (although the MFR was higher).

[0092] Example 9 In the resin composition of Example 9, the base resin was polycarbonate resin (AD-5503), which accounted for 90% by mass of the composition, and the acetal compound was prepared by reacting xylose, a sugar raw material, with cinnamaldehyde. The molecular weight of the acetal compound was 378. The physical properties of the resin composition of Example 9 were found to be almost the same as those of polycarbonate resin (AD-5503) (although the MFR was higher and the nominal strain at break was lower).

[0093] (Examples 10, 11, 12, and Comparative Example 2) Examples 10, 11, 12, and Comparative Example 2 use the same base resin and acetal compound as Example 1, but the proportions of the base resin in the resin composition are different, 95 mass%, 85 mass%, 70 mass%, and 65 mass%, respectively. The physical properties of the resin compositions of Examples 10 and 11 are almost the same as those of a styrene-based resin (HF77) (however, the MFR is larger), and it can be seen that they are almost the same as the physical properties of the resin composition of Example 1.

[0094] On the other hand, the physical properties of the resin composition of Example 12 were slightly worse, with a haze of 3.5%, and a significantly higher MFR. The physical properties of the resin composition of Comparative Example 2 were a total light transmittance of 75.3%, which was below the target total light transmittance of 80%, and a haze of 10.3%, which exceeded the preferred haze value of 4%. For this reason, the content of the base resin in the resin composition is preferably 70% by mass or more, and more preferably 85% by mass or more.

[0095] Comparative Example 1 The resin composition of Comparative Example 1 had a styrene-based resin as the base resin, accounting for 90% by mass of the composition, and the acetal compound was prepared by reacting xylooligosaccharides with 3,4,5-trimethoxybenzaldehyde (biomass-derived) as the raw sugar. The molecular weight of the acetal compound was 1089. The physical properties of the resin composition of Comparative Example 1 were a total light transmittance of 69.8%, below the target total light transmittance of 80%, and a haze of 17.8%, exceeding the preferred haze value of 4%. Compared to Examples 4 and 5, it can be inferred that a larger molecular weight of the acetal compound leads to a worsening of the total light transmittance and haze. Considering the molecular weights of the acetal compounds in Examples 1 to 10, it is believed that the molecular weight of the acetal compound is preferably 200 or more and 1000 or less.

[0096] (Comparative Examples 3 and 4) The resin compositions of Comparative Examples 3 and 4 have a styrene-based resin as the base resin, accounting for 90% by mass of the composition, and are kneaded with 10% by mass of xylooligosaccharide, a polysaccharide, and xylose, a monosaccharide. In other words, the resin compositions of Comparative Examples 3 and 4 do not contain an acetal compound. The physical properties of the resin composition of Comparative Example 3 are a total light transmittance of 43.6%, which is below the target total light transmittance of 80%, and a haze of 99.2%, which is significantly higher than the desired haze value of 4%. Furthermore, the resin composition of Comparative Example 4 could not be injected by injection molding, so test pieces could not be produced. Therefore, the physical properties of Comparative Example 4 are not listed.

Claims

1. A resin composition having excellent transparency, comprising: a base resin containing at least one of a styrene-based resin, a polycarbonate resin, and an acrylic resin; and an acetal compound in which at least a portion of the hydroxyl groups of a monosaccharide or oligosaccharide has reacted with an aldehyde, wherein the content of the base resin in the resin composition is 70% by mass or more and 97% by mass or less, and the acetal compound has a molecular weight of 200 or more and 1,000 or less.

2. A resin composition having excellent transparency as described in claim 1, wherein the content of the base resin in the resin composition is 85% by mass or more and 95% by mass or less.

3. The resin composition having excellent transparency according to claim 1, wherein the aldehydes are derived from biomass.

4. The resin composition having excellent transparency according to claim 3, wherein the aldehyde is at least one of anisaldehyde, cinnamaldehyde, furfural, and glyoxylic acid.

5. The resin composition having excellent transparency according to claim 4, wherein the aldehyde is cinnamaldehyde.

6. A molded article comprising the resin composition having excellent transparency described in any one of claims 1 to 5.

Images