Ultraviolet absorbent and resin composition containing same

Abstract

[Problem] To provide an ultraviolet absorbent which has excellent ultraviolet absorbing properties and biodegradability, and a resin composition which contains the same. [Solution] Disclosed is an ultraviolet absorbent which contains flavonoids represented by general formula (1). General formula (1) (In the formula, R1 to R4 each independently represent a hydrogen atom, a halogen atom, an alkyl group having 1 to 8 carbon atoms (which may have one or more substituents other than an alkyl group in the alkyl chain), a hydroxy group, an alkyloxy group having 1 to 8 carbon atoms (which may have one or more substituents other than an alkyl group in the alkyl chain, may have one or more ether bonds in the alkyl chain, but does not have a cyclic structure), a formyloxy group, and an alkylcarbonyloxy group having 1 to 7 alkyl carbon atoms (which may have one or more substituents other than an alkyl group in the alkyl chain), an amino group, a monoalkylamino group having 1 to 4 alkyl carbon atoms, a dialkylamino group having a total of 2 to 8 alkyl carbon atoms, a nitro group, a carboxyl group, or an alkyloxycarbonyl group having 1 to 8 alkyl carbon atoms (which may have one or more substituents other than an alkyl group in the alkyl chain); R5 represents a hydrogen atom or a hydroxy group; the bond M represents a single bond or a double bond; R6 represents a hydrogen atom or a hydroxy group when the bond M represents a single bond; and R6 is not present when the bond M represents a double bond.)

Description

Ultraviolet absorber and resin composition containing same

[0001] The present invention relates to a novel ultraviolet absorber containing a flavonoid, and further to an ultraviolet absorber using the flavonoid that combines excellent ultraviolet absorption and biodegradability, and a resin composition containing the flavonoid.

[0002] It is well known that resins deteriorate due to the action of ultraviolet rays from natural light, resulting in phenomena such as softening, embrittlement, and discoloration, resulting in a significant decrease in their mechanical strength. UV absorbers have traditionally been added during resin processing to prevent UV-induced deterioration of resins, and are used in a variety of fields, including automotive components, building materials, electronic materials, medical materials, containers, packaging materials, and agricultural and fishing materials. Known UV absorbers for use in resins include, for example, various organic compounds such as benzophenones, benzotriazoles, and triazines.

[0003] However, the above-mentioned ultraviolet absorbers currently used in resins are difficult to biodegrade, and therefore remain in soil, rivers, and oceans, and may be taken up by the human body via fish, etc. Furthermore, there are concerns about the adverse effects of ultraviolet absorbers on the human body due to their toxicity and bioaccumulation. Under these circumstances, there is a demand for the development of safe ultraviolet absorbers that are biodegradable in the natural environment.

[0004] On the other hand, biodegradable resins that are biodegradable in the natural environment undergo biodegradation in soil, rivers, and oceans, breaking down into water and carbon dioxide, and therefore do not remain in the environment. As such, they have recently been used as resins with low environmental impact in agricultural and fishing materials, containers, medical materials, etc. However, to prevent degradation of biodegradable resins by ultraviolet light, benzophenone-based, benzotriazole-based, or triazine-based ultraviolet absorbers that are less likely to biodegrade are used. Although the biodegradable resins are biodegradable, the ultraviolet absorbers continue to remain in the environment, so a fundamental solution to environmental pollution has not been achieved. Under these circumstances, there is a need for the development of ultraviolet absorbers that are biodegradable together with biodegradable resins in the natural environment.

[0005] Patent Document 1 proposes a lignocellulose membrane containing biodegradable lignin as an ultraviolet absorber. However, it is known that lignin absorbs ultraviolet light, generating radicals and causing photooxidation, which can lead to yellowing and decomposition into low-molecular-weight compounds, resulting in changes in absorption properties. These properties are undesirable as an ultraviolet absorber, limiting its applications.

[0006] Patent Documents 2 and 3 propose the use of flavonoid glycosides, such as α-glucosyldiosmin and eriocitrin, in which a cyclic sugar has been introduced into a flavonoid, as ultraviolet absorbents. However, these glycosides are highly water-soluble due to the influence of the cyclic sugar, and are thought to be difficult to dissolve in plastics. In addition, the cyclic sugars also cause the glycosides to have large molecular weights, resulting in low absorbance per weight. These properties make them undesirable as ultraviolet absorbents for use in plastics, and their applications are limited.

[0007] Japanese Patent Publication No. 4-33986 Japanese Publication No. 2001-158796 Japanese Publication No. 2001-200238

[0008] Under these circumstances, an object of the present invention is to provide an ultraviolet absorber that has excellent ultraviolet absorbing properties and is biodegradable, and a resin composition containing the same.

[0009] In the present invention, the main means for solving the above problems is to use a flavonoid represented by the following general formula (1) as an ultraviolet absorber and a resin composition.

[0010] General formula (1) [wherein, R １each R4 independently represents a hydrogen atom, a halogen atom, an alkyl group having 1 to 8 carbon atoms (which may have one or more substituents other than alkyl groups in the alkyl chain), a hydroxy group, an alkyloxy group having 1 to 8 carbon atoms (which may have one or more substituents other than alkyl groups in the alkyl chain and may have one or more ether bonds in the alkyl chain, but does not have a cyclic structure), a formyloxy group, an alkylcarbonyloxy group having 1 to 7 alkyl carbon atoms (which may have one or more substituents other than alkyl groups in the alkyl chain), an amino group, a monoalkylamino group having 1 to 4 alkyl carbon atoms, a dialkylamino group having 2 to 8 alkyl carbon atoms in total, a nitro group, a carboxyl group, or an alkyloxycarbonyl group having 1 to 8 alkyl carbon atoms (which may have one or more substituents other than alkyl groups in the alkyl chain); R5 represents a hydrogen atom or a hydroxy group; the bond M represents a single bond or a double bond; R6 represents a hydrogen atom or a hydroxy group when the bond M represents a single bond; and R6 does not exist when the bond M represents a double bond.

[0011] More preferably, R in the above general formula (1) １ R 1 to R 4 are each independently a hydrogen atom, a hydroxy group, an alkyloxy group having 1 to 8 carbon atoms, a formyloxy group, or an alkylcarbonyloxy group having 1 to 7 alkyl carbon atoms.

[0012] The ultraviolet absorbent of the present invention has both excellent ultraviolet absorption and biodegradability, and therefore is biodegradable in the natural environment and does not remain, while preventing deterioration of resins due to ultraviolet rays. Therefore, the ultraviolet absorbent and resin composition of the present invention are useful as ultraviolet absorbents and resin compositions that can solve the problems of the prior art.

[0013] 1 shows the ultraviolet-visible absorption spectrum of a polycarbonate film of compound (a). 2 shows the ultraviolet-visible absorption spectrum of a polylactic acid film of compound (a). 3 shows the ultraviolet-visible absorption spectrum of a polylactic acid film of compound (b). 4 shows the ultraviolet-visible absorption spectrum of a polylactic acid film of compound (c). 5 shows the ultraviolet-visible absorption spectrum of a polylactic acid film of compound (d). 6 shows the ultraviolet-visible absorption spectrum of a polylactic acid film of compound (e). 7 shows the ultraviolet-visible absorption spectrum of a polyvinyl alcohol film of compound (e). 8 shows the ultraviolet-visible absorption spectrum of a polyvinyl alcohol film of compound (f). 9 shows the ultraviolet-visible absorption spectrum of a polyvinyl alcohol film of compound (g). 10 shows the ultraviolet-visible absorption spectrum of a polyvinyl alcohol film of compound (h).

[0014] The present invention is described in detail below. The present invention relates to an ultraviolet absorber containing a flavonoid represented by the following general formula (1) and a resin composition containing the same. The flavonoid represented by the following general formula (1) is described below.

[0015] General formula (1)

[0016] In general formula (1), R １to R4 are each independently a hydrogen atom; a halogen atom; an alkyl group having 1 to 8 carbon atoms such as a methyl group, an ethyl group, a propyl group, an isopropyl group, a butyl group, an isobutyl group, a sec-butyl group, a tert-butyl group, a hexyl group, an octyl group, a 2-ethylhexyl group, a 2-hydroxyethyl group, an 8-hydroxyoctyl group, or a 2-aminoethyl group (which may have one or more substituents other than an alkyl group in the alkyl chain); a hydroxy group; an alkyloxy group having 1 to 8 carbon atoms such as a methoxy group, an ethoxy group, a propyloxy group, a butoxy group, an octoxy group, or a 2-(2-hydroxyethoxy)ethoxy group (which may have one or more substituents other than an alkyl group in the alkyl chain and may have one or more ether bonds in the alkyl chain, but does not have a cyclic structure); a formyloxy group; a methylcarbonyloxy group, an ethylcarbonyloxy group, a propylcarbonyloxy group, or a heptylcarbonyloxy group. a 2-hydroxyethylcarbonyloxy group or an alkylcarbonyloxy group having 1 to 7 alkyl carbon atoms (which may have one or more substituents other than alkyl groups in the alkyl chain); an amino group; a monoalkylamino group having 1 to 4 alkyl carbon atoms, such as an N-methylamino group or an N-butylamino group; a dialkylamino group having 2 to 8 alkyl carbon atoms in total, such as an N,N-dimethylamino group or an N,N-dibutylamino group; a nitro group; a carboxyl group; or an alkyloxycarbonyl group having 1 to 8 alkyl carbon atoms (which may have one or more substituents other than alkyl groups in the alkyl chain), such as a methoxycarbonyl group, an octoxycarbonyl group or a 4-hydroxybutyloxycarbonyl group; R5 represents a hydrogen atom or a hydroxy group; the bond M represents a single bond or a double bond; R6 represents a hydrogen atom or a hydroxy group when the bond M represents a single bond; and R6 does not exist when the bond M represents a double bond.

[0017] Preferably, R in the general formula (1) １ Each of R to R4 independently represents a hydrogen atom, a hydroxy group, an alkyloxy group having 1 to 8 carbon atoms, a formyloxy group, or an alkylcarbonyloxy group having 1 to 7 alkyl carbon atoms.

[0018] Specific examples of flavonoids represented by the above general formula (1) include the following: 5-hydroxyflavanone, 5,7-dihydroxyflavanone, 5-hydroxy-7-octoxyflavanone, 7-acetoxy-5-hydroxyflavanone, 4',5,7-trihydroxyflavanone, 3',4',5,7-tetrahydroxyflavanone, 3',5,7-trihydroxy-4'-methoxyflavanone, 3',5-dihydroxy-4',7-dimethoxyflavanone, 4',5-dihydroxy-3',7-dimethoxyflavanone, 5-hydroxy-3',4',7-trimethoxyflavanone, 5-hydroxyflavone, 5,7-dihydroxyflavone, 5-hydroxy-7-octoxyflavone, 7-acetoxy-5 5-hydroxyflavone, 5-hydroxy-7-methylflavone, 7-amino-5-hydroxyflavone, 5-hydroxy-7-methylaminoflavone, 5-hydroxy-7-dimethylaminoflavone, 5-hydroxy-7-nitroflavone, 7-carboxy-5-hydroxyflavone, 5-hydroxy-7-methoxycarbonylflavone, 5,6,7-trihydroxyflavone, 3',4',5,7-tetrahydroxyflavone, 3',5,7-trihydroxy-4'-methoxyflavone, 3',5-dihydroxy-4',7-dimethoxyflavone, 4',5-dihydroxy-3',7-dimethoxyflavone, 5-hydroxy-3',4',7-trimethoxyflavone, 2',3,4',5,7-pentahydroxyflavone, and 3,3',4',5,7-pentahydroxyflavone.

[0019] Among the flavonoids exemplified herein, particularly preferred are 5-hydroxyflavanone, 5,7-dihydroxyflavanone, 5-hydroxy-7-octoxyflavanone, 7-acetoxy-5-hydroxyflavanone, 4',5,7-trihydroxyflavanone, 3',4',5,7-tetrahydroxyflavanone, 3',5,7-trihydroxy-4'-methoxyflavanone, 3',5-dihydroxy-4',7-dimethoxyflavanone, 4',5-dihydroxy-3',7-dimethoxyflavanone, 5-hydroxy-3',4',7-trimethoxyflavanone, 5-hydroxyflavone, 5,7- Dihydroxyflavone, 5-hydroxy-7-octoxyflavone, 7-acetoxy-5-hydroxyflavone, 5,6,7-trihydroxyflavone, 3',4',5,7-tetrahydroxyflavone, 3',5,7-trihydroxy-4'-methoxyflavone, 3',5-dihydroxy-4',7-dimethoxyflavone, 4',5-dihydroxy-3',7-dimethoxyflavone, 5-hydroxy-3',4',7-trimethoxyflavone, 2',3,4',5,7-pentahydroxyflavone, and 3,3',4',5,7-pentahydroxyflavone can be preferably used.

[0020] The method for synthesizing the flavonoids of the general formula (1) of the present invention is not particularly limited, and a wide variety of conventionally known reaction principles can be used. For example, the flavonoids can be synthesized by the reactions shown in the following reaction formula 1 or 2.

[0021] The ultraviolet absorber containing the flavonoids of the present invention can be used alone or in combination with other ultraviolet absorbers. The other ultraviolet absorbers to be used in combination are not particularly limited as long as they can absorb ultraviolet light, such as those generally available on the market, and examples thereof include benzophenone-based, benzotriazole-based, and triazine-based ultraviolet absorbers. These may be used alone or in a suitable mixture of two or more.

[0022] When the ultraviolet absorber containing the flavonoids of the present invention is blended into a resin material, examples of the resin material include α-olefin polymers such as polyethylene, polypropylene, polybutene, polypentene, poly-3-methylbutylene, and polymethylpentene, polyolefins such as ethylene-vinyl acetate copolymer and ethylene-propylene copolymer, polyvinyl chloride, polyvinyl bromide, polyvinyl fluoride, chlorinated polyethylene, chlorinated polypropylene, brominated polyethylene, chlorinated rubber, vinyl chloride-vinyl acetate copolymer, vinyl chloride-ethylene copolymer, vinyl chloride-propylene copolymer, vinyl chloride-styrene copolymer, vinyl chloride-isobutylene copolymer, vinyl chloride-vinylidene chloride copolymer, vinyl chloride-styrene-maleic anhydride terpolymer, vinyl chloride-styrene-acrylonitrile terpolymer, vinyl chloride-butadiene copolymer, vinyl chloride-isobutylene copolymer, vinyl chloride-chlorinated propylene copolymer, vinyl chloride-vinylidene chloride-vinyl acetate terpolymer, vinyl chloride-acrylic acid ester copolymer, vinyl chloride-maleic acid ester copolymer, and vinyl chloride-methacrylic acid ester copolymer. vinyl chloride-acrylonitrile copolymer, internally plasticized polyvinyl chloride and other halogen-containing synthetic resins, petroleum resin, coumarone resin, polystyrene, copolymers of styrene and other monomers (maleic anhydride, butadiene, acrylonitrile, etc.), styrene-based resins such as acrylonitrile-butadiene-styrene resin, acrylic ester-butadiene-styrene resin, methacrylic ester-butadiene-styrene resin, polyvinyl acetate, polyvinyl alcohol, polyvinyl formal, polyvinyl butyral, acrylic resin, methacrylate resin, polyacrylic Lylonitrile, polyphenylene oxide, polycarbonate, modified polyphenylene oxide, polyacetal, phenolic resin, urea resin, melamine resin, epoxy resin, silicone resin, polyethylene terephthalate, reinforced polyethylene terephthalate, polybutylene terephthalate, polysulfone resin, polyethersulfone, polyphenylene sulfide, polyetherketone, polyetherimide, polyoxybenzoyl, polyimide, polymaleimide, polyamideimide, alkyd resin, amino resin, vinyl resin, water-soluble resin, resin for powder coating,Examples of the resin include non-biodegradable resins such as polyamide resin, polyurethane resin, and unsaturated polyester resin, as well as biodegradable resins such as polylactic acid, polyvinyl alcohol, nylon 4, poly 3-hydroxybutyrate, 3-hydroxybutyrate-co-hexanoate polymer, poly ε-caprolactone, polybutylene succinate, and cellulose acetate.

[0023] The flavonoid-containing ultraviolet absorber of the present invention is preferably contained in the resin material in an amount of 0.01 to 20%, more preferably 0.1 to 10%.

[0024] The resin composition containing the flavonoids of the present invention may contain additives for resins other than ultraviolet absorbers, such as antioxidants, light stabilizers, plasticizers, antistatic agents, flame retardants, colorants, lubricants, and foaming agents.

[0025] The resin composition containing the flavonoids of the present invention can be molded by a general resin molding method such as injection molding, blow molding, extrusion molding, etc. When molding a film or sheet, in addition to the above, a solution casting method or a casting method can be used.

[0026] Hereinafter, synthesis examples of the flavonoids of the present invention will be shown, and the properties of the flavonoids and resin compositions will be described in detail with reference to examples, but the present invention is not limited to these embodiments.

[0027] Synthesis Example 1 [Synthesis of Compound (a): 5-hydroxy-3',4',7-trimethoxyflavone] Compound (a)

[0028] A 300 ml four-neck flask was fitted with a ball condenser, a thermometer, and a stirrer, and 6.43 g (0.021 mol) of 3',5,7-trihydroxy-4'-methoxyflavone (Tokyo Chemical Industry Co., Ltd.), 63 ml of N,N-dimethylformamide, and 51.03 g (0.48 mol) of soda ash were added. 60.74 g (0.48 mol) of dimethyl sulfate was added dropwise over 20 minutes at 10°C, and the mixture was stirred at 50°C for 3 hours. Subsequently, 150 ml of ethyl acetate and 400 ml of water were added, and the lower layer was removed at 55°C. 100 ml of water and 10 ml of acetic acid were added, and the lower layer was removed at 55°C. The organic solvent was then distilled off under reduced pressure. Subsequently, 60 ml of 2-propanol was added, the mixture was heated to 70°C, then cooled to 15°C, filtered, washed with 2-propanol, and dried to obtain a crude product of 5-hydroxy-3',4',7-trimethoxyflavone. A 300 ml four-neck flask equipped with a ball condenser, a thermometer, and a stirrer was charged with the crude product, 50 ml of toluene, and 2 ml of N,N-dimethylformamide. The mixture was heated to 70°C and then cooled to 20°C. The mixture was filtered, washed with toluene, and dried to give 2.35 g (34% yield) of 5-hydroxy-3',4',7-trimethoxyflavone as a yellow powder. The melting point was 168°C.

[0029] The purity of compound (a) was measured by HPLC analysis. <HPLC measurement conditions> Apparatus: Chromaster-5110 (Hitachi High-Technologies Corporation) Column: SUMIPAX ODS A-212 6×150 mm 5 μm Column temperature: 40° C. Mobile phase: methanol / water=8 / 2 (phosphoric acid 3 ml / L) Flow rate: 1.0 ml / min <Measurement results> HPLC area purity: 98.1% The following compounds (c) and (d) were also subjected to HPLC analysis under the same measurement conditions as compound (a).

[0030] Furthermore, when the ultraviolet-visible absorption spectrum of compound (a) was measured, the maximum absorption wavelength λmax was 338 nm, and the molar extinction coefficient ε at this time was 23,500. The conditions for measuring the spectrum are as follows: <Measurement conditions> Apparatus: UV-1850 (manufactured by Shimadzu Corporation) Measurement wavelength: 250 to 450 nm Solvent: chloroform Concentration: 10 ppm Cell: 1 cm quartz Note that the ultraviolet-visible absorption spectra of the following compounds (b) to (d) were also measured under the same measurement conditions as for compound (a).

[0031] Furthermore, NMR analysis of compound (a) yielded results supporting the above structure. The measurement conditions were as follows. <Measurement conditions> Apparatus: ECX-500 (II) (manufactured by JEOL Ltd.) Resonance frequency: 500 MHz (1H-NMR) Solvent: Chloroform-d Tetramethylsilane was used as the internal standard substance for 1H-NMR, and the chemical shift value was expressed in δ (ppm), and the coupling constant was expressed in Hertz. Furthermore, s stands for singlet, d for double, dd for double double, t for triplet, and m for multiplet. The 1H-NMR spectra of the following compounds (b) to (d) were also measured under the same measurement conditions as for compound (a). The details of the obtained 1H-NMR spectra are as follows: δ 12.80 (s, 1H, OH), 7.53 (dd, J = 8.4, 1.5Hz, 1H, Flavone-H), 7.34 (d, J = 2.3Hz, 1H, Flavone-H), 6.98 (d, J = 8.4Hz, 1H, Flavone-H), 6.59 (s, 1H, Flavone-H), 6.50 (d, J = 2.3Hz, 1H, Flavone-H), 6.37 (d, J = 2.3Hz, 1H, Flavo ne-H), 3.99 (s, 3H, Methoxy-H), 3.97 (s, 3H, Methoxy-H), 3.89 (s, 3H, Methoxy-H).

[0032] Synthesis Example 2 [Synthesis of Compound (b): 5-hydroxy-7-octoxyflavone] Compound (b)

[0033] A 300 ml four-neck flask was fitted with a ball condenser, a thermometer, and a stirrer, and 7.00 g (0.028 mol) of 5,7-dihydroxyflavone (Tokyo Chemical Industry Co., Ltd.), 21 ml of N,N-dimethylformamide, 2.33 g (0.022 mol) of soda ash, 4.62 g (0.031 mol) of 1-chlorooctane, 1.35 g of polyethylene glycol 400, and 0.12 g of potassium iodide were added and mixed, followed by stirring for 16 hours at 80 to 95° C. Subsequently, 60 ml of toluene and 60 ml of water were added, and the lower layer was removed at 80° C., 60 ml of water was added, the lower layer water was removed at 80° C., and the organic solvent was distilled off under reduced pressure. Subsequently, 50 ml of methanol was added, the temperature was raised to 60°C, and then cooled to 5°C. The crystals were filtered, washed with methanol, and dried to obtain 9.50 g (yield 94%) of 5-hydroxy-7-octoxylavone as a pale yellow powder. The melting point was 102°C.

[0034] The purity of compound (b) was measured by HPLC analysis. <HPLC measurement conditions> Apparatus: Chromaster-5110 (Hitachi High-Technologies Corporation) Column: SUMIPAX ODS A-212 6 x 150 mm 5 µm Column temperature: 40°C Mobile phase: methanol / water = 95 / 5 (phosphoric acid 3 ml / L) Flow rate: 1.0 ml / min <Measurement results> HPLC surface purity: 99.5%

[0035] Furthermore, when the ultraviolet-visible absorption spectrum of compound (b) was measured, the maximum absorption wavelength λmax was 271 nm, and the molar absorption coefficient ε at this time was 31,100.

[0036] Furthermore, NMR analysis of compound (b) provided results supporting the above structure. δ 12.71 (s, 1H, OH), 7.90-7.88 (m, 2H, Flavone-H), 7.57-7.51 (m, 3H, Flavone-H), 6.67 (s, 1H, Flavone-H), 6.50 (d, J = 2.3 Hz, 1H, Flavone-H), 6.37 (d, J = 2.3 Hz, 1H, Flavone-H). ), 4.03 (t, J = 6.9Hz, 2H, Methylene-H), 1.85-1.79 (m, 2H, Methylene-H), 1.49-1.44 (m , 2H, Methylene-H), 1.38-1.30 (m, 8H, Methylene-H), 0.90 (t, J=6.9Hz, 3H, Methyl-H).

[0037] Synthesis Example 3 [Synthesis of Compound (c): 7-acetoxy-5-hydroxy-flavone] Compound (c)

[0038] A 300 ml four-neck flask was equipped with a ball condenser, thermometer, and stirrer. 7.00 g (0.028 mol) of 5,7-dihydroxyflavone (Tokyo Chemical Industry Co., Ltd.), 28 ml of acetic acid, 3.37 g (0.033 mol) of acetic anhydride, and 0.1 ml of 95% sulfuric acid were added and mixed, followed by stirring at 80-90 °C for 3.5 hours. Subsequently, 30 ml of water was added, the mixture was cooled to 20 °C, and the crystals were filtered, washed with water, and dried to obtain a crude product of 5-hydroxy-7-acetoxyflavone. A 300 ml four-neck flask was equipped with a ball condenser, thermometer, and stirrer. 23 ml of acetic acid and the resulting crude product were added, heated to 78 °C, cooled to 20 °C, filtered, washed with acetic acid and 2-propanol, and dried to obtain 5.18 g (63% yield) of 5-hydroxy-7-acetoxyflavone as a yellow powder. The melting point was 171°C and the HPLC surface purity was 99.5%.

[0039] Furthermore, when the ultraviolet-visible absorption spectrum of compound (c) was measured, the maximum absorption wavelength λmax was 271 nm, and the molar absorption coefficient ε at this time was 29,700.

[0040] Furthermore, NMR analysis of compound (c) provided results supporting the above structure. The obtained 1H-NMR spectrum was as follows: δ 12.74 (s, 1H, OH), 7.90-7.88 (m, 2H, Flavone-H), 7.59-7.52 (m, 3H, Flavone-H), 6.87 (d, J=2.3 Hz, 1H, Flavone-H), 6.74 (s, 1H, Flavone-H), 6.58 (d, J=2.3 Hz, 1H, Flavone-H), 2.35 (s, 3H, Acetyl-H). (Synthesis Example 4) [Synthesis of compound (d); 5-hydroxy-3',4',7-trimethoxyflavanone] Compound (d)

[0041] A stirrer was placed in a 30 ml recovery flask, and 0.60 g (1.98 mmol) of 3',5,7-trihydroxy-4'-methoxyflavanone (Tokyo Chemical Industry Co., Ltd.), 7 ml of 4-methyl-2-pentanone, and 5.20 g (49.0 mmol) of soda ash were added. 6.50 g (51.5 mmol) of dimethyl sulfate was added dropwise at 50°C over 10 minutes, and the mixture was stirred at 50°C for 16 hours. Subsequently, 15 ml of water was added, and the lower layer was removed at 70°C. 10 ml of water and 0.5 ml of acetic acid were added, and the lower layer was removed at 70°C. Another 10 ml of water was added, and the lower layer was removed at 70°C. The organic solvent was then distilled off under reduced pressure. Subsequently, 10 ml of methanol was added, and the mixture was heated to 65°C, then cooled to 20°C, filtered, washed with methanol, and dried to obtain a crude product of 5-hydroxy-3',4',7-trimethoxyflavanone. A stirrer was placed in a 30 ml recovery flask, the resulting crude product, 3 ml of methanol, and 3 ml of 2-propanol were added, and the mixture was heated to 65°C, cooled to 20°C, filtered, washed with methanol and 2-propanol, and dried to obtain 0.15 g (25% yield) of 5-hydroxy-3',4',7-trimethoxyflavanone as a white powder. The melting point was 135°C, and the HPLC surface purity was 95.6%.

[0042] Furthermore, when the ultraviolet-visible absorption spectrum of compound (d) was measured, the maximum absorption wavelength λmax was 288 nm, and the molar absorption coefficient ε at this time was 21,400.

[0043] Furthermore, NMR analysis of compound (d) yielded results supporting the above structure. The obtained 1H-NMR spectrum contains the following: δ 12.04 (s, 1H, OH), 6.99 (dd, J = 6.1, 1.5 Hz, 2H, Flavanone-H), 6.91 (m, 1H, Flavanone-H), 6.07 (dd, J = 8.4, 2.3 Hz, 2H, Flavanone-H), 5.37 (dd, J = 13.0, 3.1 Hz, 1H , Flavanone-H), 3.93 (s, 3H, Methoxy-H), 3.91 (s, 3H, Methoxy-H), 3.82 (s, 3H, Methoxy-H), 3.09-3.15 (m, 1H, Flavanone-H), 2.79-2.83 (m, 1H, Flavanone-H).

[0044] Example 1 Preparation of Polycarbonate Resin Compositions 5 g of polycarbonate resin pellets (TARFLON IR2200 manufactured by FORMOSA IDEMITSU PETROCHEMICAL CORPORATION) were added to separate 100 ml measuring flasks, and 0.01 g each of compound (a) obtained in Synthesis Example 1 and compound (i), a conventional UV absorber (2-(2-hydroxy-5-methylphenyl)-2H-benzotriazole) as a comparative example, were added. The mixture was then diluted with dichloromethane and allowed to stand for 24 hours to obtain solutions of polycarbonate resin compositions containing UV absorbers. 20 ml of the resulting polycarbonate resin composition solutions containing UV absorbers were transferred to 12 cm diameter Petri dishes and dried at 25°C for 48 hours to remove the solvent, yielding 0.05 mm thick films of polycarbonate resin compositions containing 0.2% UV absorber.

[0045] [Preparation of Polylactic Acid Resin Compositions] 5 g of biodegradable polylactic acid resin pellets (Standard Test Piece, standard / general-purpose grade) were added to separate 100 ml screw tubes, and 0.005 g each of compounds (a), (b), (c), and (d) obtained in Synthesis Examples 1 to 4, compound (e); 4',5,7-trihydroxyflavanone (Tokyo Chemical Industry Co., Ltd.), and, as a comparative example, compound (i) and compound (j); 2,4-dihydroxybenzophenone, a conventional UV absorber, were added. 100 ml of dichloromethane was added and the mixture was allowed to stand for 24 hours to obtain solutions of polylactic acid resin compositions containing UV absorbers. 40 ml of each of the prepared polylactic acid resin composition solutions containing UV absorbers was added to a 12.5 x 10.0 cm fluororesin-coated SUS tray and dried at 25°C for 24 hours to remove the solvent, yielding 0.1 mm-thick films of polylactic acid resin compositions containing 0.1% UV absorbers.

[0046] [Preparation of Polyvinyl Alcohol Resin Composition] 80 g of biodegradable resin polyvinyl alcohol (manufactured by Tokyo Chemical Industry Co., Ltd.: n = approximately 2000, saponification degree approximately 80 mol%) and 1520 g of pure water were added to a 2 L four-neck flask and stirred at 25 ° C for 48 hours using a stirrer to prepare 1600 g of an aqueous polyvinyl alcohol solution. 200 g of the prepared aqueous polyvinyl alcohol solution was transferred to separate PP containers, and 0.002 g of the compound (e), compound (f); 5,6,7-trihydroxyflavone (manufactured by Tokyo Chemical Industry Co., Ltd.), compound (g); 3',4',5,7-tetrahydroxyflavone (manufactured by Tokyo Chemical Industry Co., Ltd.), compound (h); 3,3',4',5,7-pentahydroxyflavone hydrate (manufactured by Tokyo Chemical Industry Co., Ltd.), and the compounds (i) and (j) used as comparative examples were added. The mixture was stirred and dispersed at 25 ° C for 3 hours using a stirrer. 100 g of each of the prepared dispersions was added to a 12.5 × 10.0 cm fluororesin-coated SUS tray, and dried at 40°C under normal pressure for 40 hours and then under vacuum for 3 hours to obtain a film of a polyvinyl alcohol resin composition having a thickness of 0.3 mm and containing 0.02% of an ultraviolet absorber dispersed therein.

[0047] [Measurement of UV-Visible Absorption Spectra] The UV-Visible absorption spectra of the films of the polycarbonate, polylactic acid, and polyvinyl alcohol resin compositions obtained above were measured under the following conditions. The absorbance at the maximum absorption wavelength is shown in Table 1 below, the spectrum of the polycarbonate film of compound (a) is shown in Figure 1, the spectra of the polylactic acid films of compounds (a) to (e) are shown in Figures 2 to 6, and the spectra of the polyvinyl alcohol films of compounds (e) to (h) are shown in Figures 7 to 10.

[0048] <Measurement conditions> Apparatus: UV-1850 (Shimadzu Corporation) Measurement wavelength: Polycarbonate film: 300 to 450 nm Polylactic acid film and polyvinyl alcohol film: 250 to 450 nm

[0049]

[0050] [Measurement of Biochemical Oxygen Demand] Aqueous solutions containing 5 ppm of compounds (e), (f), (g), and (h) and, as comparative examples, compounds (i) and (j) were prepared, and the biochemical oxygen demand (hereinafter referred to as BOD) was measured according to JIS K 0102 (2019) 21 and 32.3. The BOD measurement results are shown in Table 2 below.

[0051]

[0052] Table 1 shows that the ultraviolet absorber of the present invention strongly absorbs light in the ultraviolet region in each resin and exhibits ultraviolet absorption properties similar to those of conventional ultraviolet absorbers. Table 2 also shows that the ultraviolet absorber of the present invention has a higher BOD value than conventional ultraviolet absorbers and is susceptible to biodegradation by microorganisms, and therefore has the property of being less likely to decompose and remain in the natural environment. Therefore, it can be seen that the ultraviolet absorber of the present invention and resin compositions containing it exhibit ultraviolet absorption properties similar to those of conventional products, while being highly safe and capable of reducing the environmental load.

[0053] The ultraviolet absorber of the present invention strongly absorbs light in the ultraviolet region in resins and exhibits ultraviolet absorption properties similar to those of conventional ultraviolet absorbers. Furthermore, the ultraviolet absorber of the present invention is more susceptible to biodegradation than conventional ultraviolet absorbers, and therefore is less likely to decompose and remain in the natural environment. Therefore, it is highly safe and can reduce environmental impact, thereby solving environmental problems. Therefore, it can be suitably used in various resins, including biodegradable resins.

Claims

1. An ultraviolet absorber containing a flavonoid represented by the following general formula (1): General formula (1) [wherein, R １ each independently represents a hydrogen atom, a halogen atom, an alkyl group having 1 to 8 carbon atoms (which may have one or more substituents other than alkyl groups in the alkyl chain), a hydroxy group, an alkyloxy group having 1 to 8 carbon atoms (which may have one or more substituents other than alkyl groups in the alkyl chain and may have one or more ether bonds in the alkyl chain, but does not have a cyclic structure), a formyloxy group, an alkylcarbonyloxy group having 1 to 7 alkyl carbon atoms (which may have one or more substituents other than alkyl groups in the alkyl chain), an amino group, a monoalkylamino group having 1 to 4 alkyl carbon atoms, a dialkylamino group having 2 to 8 alkyl carbon atoms in total, a nitro group, a carboxyl group, or an alkyloxycarbonyl group having 1 to 8 alkyl carbon atoms (which may have one or more substituents other than alkyl groups in the alkyl chain); R represents a hydrogen atom or a hydroxy group; the bond M represents a single bond or a double bond; R represents a hydrogen atom or a hydroxy group when the bond M represents a single bond; and R does not exist when the bond M represents a double bond.

2. R in the above general formula (1) １ 2. The ultraviolet absorber containing flavonoids according to claim 1, wherein R to R4 are each independently a hydrogen atom, a hydroxy group, an alkyloxy group having 1 to 8 carbon atoms, a formyloxy group, or an alkylcarbonyloxy group having 1 to 7 alkyl carbon atoms.

3. A resin composition in which the ultraviolet absorber according to claim 1 or 2 is blended with a resin material.

4. A biodegradable resin composition comprising a biodegradable resin material containing the ultraviolet absorber according to claim 1 or 2.

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