JP2017158494A - Wavelength conversion particle for use in agricultural wavelength conversion sheet - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a wavelength conversion particle which can effectively utilize light inhibiting plant growth, and has high light resistance.SOLUTION: The wavelength conversion particle is provided that is used by being added to a wavelength conversion sheet converting a short-wavelength component of irradiation light into a long-wavelength component. The wavelength conversion particle contains: (a) one or more types of fluorescent substance; (b) a transparent material; and (c) light stabilizer. It is preferable that the fluorescent substance is a fluorescent substance which converts a short-wavelength component into a long-wavelength component and emits light, and has emission maximum wavelength 400 nm to 700 nm at an excitation maximum wavelength of 400 nm or less. It is preferable that the transparent material is transparent vinyl resin. It is preferable that the light stabilizer is hindered amine-based light stabilizer.SELECTED DRAWING: None

Description

  The present invention relates to wavelength conversion particles used by adding to an agricultural wavelength conversion sheet used when growing plants using sunlight and artificial light sources.

  For plant growth, light having a wavelength of about 450 nm for promoting germination of plants, light having a wavelength of 400 to 770 nm for contributing to photosynthesis, light having a wavelength of about 660 nm for promoting photosynthesis, germination, and flowering are required, while wavelength 400 nm. The following ultraviolet light destroys plant cells and inhibits their growth. Therefore, in combination with natural sunlight or an artificial light source, a wavelength conversion filter containing a fluorescent substance that converts ultraviolet light having a wavelength of 400 nm or less that inhibits plant growth into light having the wavelength necessary for plant growth. Thus, a technique for increasing the light amount of the specific wavelength that promotes plant growth has been developed (Patent Document 1).

JP 2012-207057 A

In general, organic phosphors and rare earth metal complexes have poor light resistance, and the light emission efficiency decreases when light is irradiated for a long period of time. Therefore, it is not suitable for a wavelength conversion sheet for plant growth that is expected to be used for a long time.
The present invention has been made paying attention to the problems as described above, and the object of the present invention is to provide wavelength conversion particles with high light resistance capable of effectively using light that inhibits plant growth. It is.

  The present inventor has intensively studied to solve the above problems, and finds that the fluorescent substance has a wavelength conversion function more stably by coating the fluorescent substance with a transparent material containing a light stabilizer, The present invention has been completed.

Specifically, the present invention provides the following.
The present invention relates to [1] wavelength conversion particles used by adding to a wavelength conversion sheet for converting a short wavelength component of irradiation light into a long wavelength component, wherein (a) one or more kinds of fluorescent substances, and (b) transparent The present invention relates to a wavelength conversion particle containing a material and (c) a light stabilizer.
Further, the present invention provides [2] (a) a fluorescent material in which the fluorescent substance emits light by converting a short wavelength component to a long wavelength component, the excitation maximum wavelength is 400 nm or less, and the emission maximum wavelength is 400 nm to 700 nm. It is related with the wavelength conversion particle | grains as described in said [1].
The present invention also relates to [3] the wavelength conversion particle according to the above [1] or [2], wherein the phosphor (a) is an organic phosphor or a rare earth metal complex.
Moreover, this invention relates to the wavelength conversion particle | grains of any one of said [1]-[3] whose [4] said (b) transparent material is transparent resin.
Moreover, this invention relates to the wavelength conversion particle | grains of any one of said [1]-[4] whose [5] said (b) transparent material is transparent vinyl resin.
Moreover, this invention relates to the wavelength conversion particle | grains of any one of said [1]-[5] whose [6] said (b) transparent material is a transparent (meth) acrylic resin.
Furthermore, the present invention relates to [7] the wavelength-converting particle according to any one of [1] to [6], wherein (c) the light stabilizer is a hindered amine light stabilizer.
In the present invention, [8] the wavelength converting particles are dissolved or dispersed in (a) one or more kinds of fluorescent substances and (b) the light stabilizer in (b) a vinyl monomer composition serving as a transparent material. And it is related with the wavelength conversion particle | grains of any one of said [1]-[7] which is the resin particle by which emulsion polymerization or suspension polymerization was carried out.
The present invention also provides [9] (c) wherein the light stabilizer is a vinyl monomer having a light stabilizing function, and is emulsion-polymerized or suspension-polymerized and (b) incorporated in a transparent material. [8] The wavelength conversion particle according to any one of [8].

  The wavelength conversion particle of the present invention is added to an agricultural sheet to form an agricultural wavelength conversion sheet, so that it does not deteriorate for a long time and can effectively use light that inhibits plant growth. Very useful.

  The materials used for the wavelength conversion particles of the present invention will be described below.

<(A) Fluorescent substance>
The (a) fluorescent substance used in the present invention can be appropriately selected according to the purpose. Specific examples of the fluorescent material include organic phosphors, inorganic phosphors, and rare earth metal complexes. Of these, organic phosphors or rare earth metal complexes are preferable, and rare earth metal complexes are preferred from the viewpoint of wavelength conversion efficiency for converting light having a wavelength harmful to plant growth into light having a wavelength that promotes plant growth. It is more preferable.

(Inorganic phosphor)
Examples of the inorganic phosphor include fluorescent particles of Y ₂ O ₂ S: Eu, Mg, Ti, oxyfluoride crystallized glass containing Er ³⁺ ions, a compound composed of strontium oxide and aluminum oxide, and a rare earth element europium ( Eu) and SrAl ₂ O ₄ to which dysprosium (Dy) is added: Eu, Dy, Sr ₄ Al ₁₄ O ₂₅ : Eu, Dy, CaAl ₂ O ₄ : Eu, Dy, and inorganic fluorescent materials such as ZnS: Cu Can be mentioned.

(Organic phosphor)
Examples of the organic phosphor include organic dyes such as cyanine dyes, pyridine dyes, rhodamine dyes, BASF Lumogen F Violet 570, Yellow083, Orange 240, Red 300, and basic dyes manufactured by Taoka Chemical Co., Ltd. Organic phosphors such as Rhodamine B, Sumiplast Yellow FL7G manufactured by Sumika Finechem Co., Ltd., MACLOLEX Fluorescent Red G manufactured by Bayer, and Yellow10GN may be used.

(Rare earth metal complex)
The metal constituting the rare earth metal complex is preferably at least one of europium and samarium, and more preferably europium, from the viewpoint of wavelength conversion efficiency.
The ligand constituting the rare earth metal complex is not particularly limited as long as it can be coordinated to the rare earth metal, and can be appropriately selected according to the metal to be used. Among these, from the viewpoint of wavelength conversion efficiency, an organic ligand is preferable, and an organic ligand capable of forming a complex with at least one of europium and samarium is preferable.

In the present invention, the ligand is not limited, but is a neutral ligand, a nitrogen-containing organic compound, a nitrogen-containing aromatic heterocyclic compound, a phosphine oxide, or an anionic ligand. It is preferably at least one selected from carboxylic acids and β-diketones.
In addition, as a ligand of the rare earth complex, a general formula R ₁ COCHR ₂ COR ₃ (wherein R ₁ represents an aryl group, an alkyl group, a cycloalkyl group, a cycloalkylalkyl group, an aralkyl group, or a substituent thereof, R ₂ Represents a hydrogen atom, an alkyl group, a cycloalkyl group, a cycloalkylalkyl group, an aralkyl group or an aryl group, and R ₃ represents an aryl group, an alkyl group, a cycloalkyl group, a cycloalkylalkyl group, an aralkyl group or a substituent thereof. (Beta) -diketone represented by this may be contained.

  β-diketones include acetylacetone, perfluoroacetylacetone, benzoyl-2-furanoylmethane, 1,3-di (3-pyridyl) -1,3-propanedione, benzoyltrifluoroacetone, benzoylacetone, 5-chloro Sulfonyl-2-thenoyltrifluoroacetone, bis (4-bromobenzoyl) methane, dibenzoylmethane, d, d-dicamphorylmethane, 1,3-dicyano-1,3-propanedione, p-bis (4 4,5,5,6,6,6-heptafluoro-1,3-hexanedinoyl) benzene, 4,4'-dimethoxydibenzoylmethane, 2,6-dimethyl-3,5-heptanedione, dinaphtho Ylmethane, dipivaloylmethane, bis (perfluoro-2-propoxypropionyl) methane, 1, 3-di (2-thienyl) -1,3-propanedione, 3- (trifluoroacetyl) -d-camphor, 6,6,6-trifluoro-2,2-dimethyl-3,5-hexanedione, 1,1,1,2,2,6,6,7,7,7-decafluoro-3,5-heptanedione, 6,6,7,7,8,8,8-heptafluoro-2,2 -Dimethyl-3,5-octanedione, 2-furyltrifluoroacetone, hexafluoroacetylacetone, 3- (heptafluorobutyryl) -d-camphor, 4,4,5,5,6,6,6-heptafluoro -1- (2-thienyl) -1,3-hexanedione, 4-methoxydibenzoylmethane, 4-methoxybenzoyl-2-furanoylmethane, 6-methyl-2,4-heptanedione, 2-naphthoyltrifluor Acetone, 2- (2-pyridyl) benzimidazole, 5,6-dihydroxy-1,10-phenanthroline, 1-phenyl-3-methyl-4-benzoyl-5-pyrazole, 1-phenyl-3-methyl-4- (4-butylbenzoyl) -5-pyrazole, 1-phenyl-3-methyl-4-isobutyryl-5-pyrazole, 1-phenyl-3-methyl-4-trifluoroacetyl-5-pyrazole, 3- (5- Phenyl-1,3,4-oxadiazol-2-yl) -2,4-pentanedione, 3-phenyl-2,4-pentanedione, 3- [3 ′, 5′-bis (phenylmethoxy) phenyl ] -1- (9-phenanthyl) -1-propane-1,3-dione, 5,5-dimethyl-1,1,1-trifluoro-2,4-hexanedione, 1-thio Nyl-3- (2-thienyl) -1,3-propanedione, 3- (t-butylhydroxymethylene) -d-camphor, 1,1,1-trifluoro-2,4-pentanedione, 1,1 , 1,2,2,3,3,7,7,8,8,9,9,9-tetradecafluoro-4,6-nonanedione, 2,2,6,6-tetramethyl-3,5- Heptanedione, 4,4,4-trifluoro-1- (2-naphthyl) -1,3-butanedione, 1,1,1-trifluoro-5,5-dimethyl-2,4-hexanedione, 2, 2,6,6-tetramethyl-3,5-heptanedione, 2,2,6,6-tetramethyl-3,5-octanedione, 2,2,6-trimethyl-3,5-heptanedione, , 2,7-Trimethyl-3,5-octanedione, 4,4,4-to Fluoro-1- (thienyl) -1,3-butanedione (TTA), 1- (pt-butylphenyl) -3- (N-methyl-3-pyrrole) -1,3-propanedione (BMPP), 1- (pt-Butylphenyl) -3- (p-methoxyphenyl) -1,3-propanedione (BMDBM), 1,3-diphenyl-1,3-propanedione, benzoylacetone, dibe Nzoylacetone, diisobutyroylmethane, dibiparoylmethane, 3-methylpentane-2,4-dione, 2,2-dimethylpentane-3,5-dione, 2-methyl-1,3-butanedione, 1, 3-butanedione, 3-phenyl-2,4-pentanedione, 1,1,1-trifluoro-2,4-pentanedione, 1,1,1-trifluoro-5,5-dimethyl-2,4-hex Sandione, 2,2,6,6-tetramethyl-3,5-heptanedione, 3-methyl-2,4-pentanedione, 2-acetylcyclopentanone, 2-acetylcyclohexanone, 1-heptafluoropropyl-3 -T-butyl-1,3-propanedione, 1,3-diphenyl-2-methyl-1,3-propanedione, 1-ethoxy-1,3-butanedione and the like can be mentioned.

  Nitrogen-containing organic compounds, nitrogen-containing aromatic heterocyclic compounds, and phosphine oxides of neutral ligands of rare earth complexes include 1,10-phenanthroline, 2-2'-bipyridyl, 2-2'-6,2 " -Terpyridyl, 4,7-diphenyl-1,10-phenanthroline, 2- (2-pyridyl) benzimidazole, triphenylphosphine oxide, tri-n-butylphosphine oxide, tri-n-octylphosphine oxide, tri-n- Examples include butyl phosphate.

Among them, Eu (TTA) ₃ (PH ₃ PO) ₂ can be preferably used as a rare earth complex having a ligand as described above (TTA; 3-thenoyltrifluoroacetonate, 4,4,4-trifluoro). -1- (thienyl) -1,3-butanedione).

  In the present invention, by combining these phosphors, it is possible to adjust the fluorescence wavelength band useful for the growth of each type of plant.

<(C) Light stabilizer>
In the present invention, known light stabilizers can be used, such as UV absorbers such as benzotriazole-based, cyanoacrylate-based, triazine-based, benzophenone-based, and oxalic acid anilide-based, hindered amine-based, and benzoate-based antioxidants. Agents. These may be used alone or in combination of two or more.
In the present invention, a hindered amine stabilizer is preferable from the viewpoint of light resistance.

Examples of the benzotriazole ultraviolet absorber include 2- (2′-hydroxy-5′-methylphenyl) benzotriazole, 2- [2′-hydroxy-3 ′, 5′-bis (α, α-dimethylbenzyl). Phenyl] benzotriazole, 2- (2′-hydroxy-3 ′, 5′-di-t-butylphenyl) benzotriazole, 2- (2′-hydroxy-3′-t-butyl-5′-methylphenyl) -5-chlorobenzotriazole, 2- (2'-hydroxy-3 ', 5'-di-t-butylphenyl) -5-chlorobenzotriazole, 2- (2'-hydroxy-3', 5'-di -T-amylphenyl) benzotriazole, 2- (2'-hydroxy-5'-t-octylphenyl) benzotriazole, 2,2'-methylene-bis [4- (1,1,3,3-teto Methylbutyl)-6-(2N-benzotriazol-2-yl) phenol] and the like.
Examples of the cyanoacrylate ultraviolet absorber include ethyl-2-cyano-3,3-diphenyl acrylate.

  Examples of triazine-based ultraviolet absorbers include 2- (2-hydroxy-4-methoxyphenyl) -4,6-diphenyl-1,3,5-triazine, 2- (2-hydroxy-4-hexyloxyphenyl)- 4,6-diphenyl-1,3,5-triazine, 2- (2-hydroxy-4-octoxyphenyl) -4,6-bis (2,4-dimethylphenyl) -1,3,5-triazine, 2- [2-hydroxy-4- (3-C12-C13 mixed alkoxy-2-hydroxypropoxy) phenyl] -4,6-bis (2,4-dimethylphenyl) -1,3,5-triazine, 2- [2-hydroxy-4- (2-acryloyloxyethoxy) phenyl] -4,6-bis (4-methylphenyl) -1,3,5-triazine, 2- [2-hydroxy-4- (2-a Tiloxyethoxy) phenyl] -4,6-bisphenyl-1,3,5-triazine, 2- (2,4-dihydroxy-3-allylphenyl) -4,6-bis (2,4-dimethylphenyl) -1,3,5-triazine, 2,4,6-tris (2-hydroxy-3-methyl-4-hexyloxyphenyl) -1,3,5-triazine and the like.

  Examples of the benzophenone-based ultraviolet absorber include 2,4-dihydroxybenzophenone, 2-hydroxy-4-methoxybenzophenone, 2-hydroxy-4-methoxybenzophenone-5-sulfonic acid, 2-hydroxy-4-octoxybenzophenone, 2-hydroxy-4-dodecyloxybenzophenone, 2-hydroxy-4-benzyloxybenzophenone, bis (5-benzoyl-4-hydroxy-2-methoxyphenyl) methane, 2,2'-dihydroxy-4-methoxybenzophenone, 2 2,2'-dihydroxy-4,4'-dimethoxybenzophenone, 2,2 ', 4,4'-tetrahydroxybenzophenone and 2-hydroxy-4-methoxy-2'-carboxybenzophenone.

Examples of oxalic acid anilide-based ultraviolet absorbers include 2-ethoxy-2'-ethyloxalic acid bisanilide, 2-ethoxy-5-t-butyl-2'-ethyloxalic acid bisanilide, 2-ethoxy- 3'-dodecyl oxalic acid bisanilide and the like.
Examples of the oxanilide ultraviolet absorber include 4,4′-dioctyl oxanilide, 2,2′-dioctyloxy-5,5′-di-t-butyl oxanilide, 2-ethoxy-4′-isododecyl oxalate. Nilide, 2-ethoxy-5-t-butyl-2'-ethyloxanilide, 2,2'-didodecyloxy-5,5'-t-dibutyloxanilide and the like.

  Examples of hindered amine-based antioxidants include 4-benzoyloxy-2,2,6,6-tetramethylpiperidine, 4-stearoyloxy-2,2,6,6-tetramethylpiperidine, 4-stearoyloxy-1, 2,2,6,6-pentamethylpiperidine, 4-methacryloyloxy-2,2,6,6-tetramethylpiperidine, 4-methacryloyloxy-1,2,2,6,6-pentamethylpiperidine, bis ( 2,2,6,6-tetramethyl-4-piperidinyl) sebacate, bis (1,2,2,6,6-pentamethyl-4-piperidinyl) sebacate, bis (2,2,6,6-tetramethyl- 1-octoxypiperidinyl) sebacate, 4- {3- (3,5-di-t-butyl-4-hydroxyphenyl) propionyloxy} -1 [2- {3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionyloxy} ethyl] -2,2,6,6-tetramethylpiperidine, bis (1,2,2,6, 6-pentamethyl-4-piperidinyl) 2-butyl-2- (3,5-di-t-butyl-4-hydroxybenzyl) malonate, 8-acetyl-3-dodecyl-7,7,9,9-tetramethyl -1,3,8-triazaspiro [4.5] decane-2,4-dione, tetrakis (2,2,6,6-tetramethyl-4-piperidinyl) 1,2,3,4-butanetetracarboxylate Tetrakis (1,2,2,6,6-pentamethyl-4-piperidinyl) 1,2,3,4-butanetetracarboxylate, tridecyl tris (2,2,6,6-tetramethyl-4-piperidin 1) 1,2,3,4-butanetetracarboxylate, tridecyl tris (1,2,2,6,6-pentamethyl-4-piperidinyl) -1,2,3,4-butanetetracarboxylate, ditridecyl Bis (2,2,6,6-tetramethyl-4-piperidinyl) 1,2,3,4-butanetetracarboxylate, ditridecyl bis (1,2,2,6,6-pentamethyl-4-piperidinyl ) 1,2,3,4-butanetetracarboxylate, 3,9-bis [1,1-dimethyl-2- {tris (2,2,6,6-tetramethyl-4-piperidinyloxycarbonyl) Butylcarbonyloxy} ethyl] -2,4,8,10-tetraoxaspiro [5.5] undecane, 3,9-bis [1,1-dimethyl-2- {tris (1,2,2,6, 6-pentamethyl-4-piperidyloxycarbonyl) butylcarbonyloxy} ethyl] -2,4,8,10-tetraoxaspiro [5.5] undecane, 2,2,4,4-tetramethyl-20- (β -Lauryloxycarbonyl) -ethyl-7-oxa-3,20-diazadispiro [5.1.1.12] heneicosan-21-one, 2,4,6-tris {N-cyclohexyl-N- (2-oxo -3,3,5,5-tetramethylpiperazino) ethyl} -1,3,5-triazine and the like.

  Examples of the benzoate ultraviolet absorber include phenyl salicylate, resorcinol monobenzoate, 2,4-di-t-butylphenyl-3,5-di-t-butyl-4-hydroxybenzoate, octyl (3,5-di-t -Butyl-4-hydroxy) benzoate, dodecyl (3,5-di-t-butyl-4-hydroxy) benzoate, tetradecyl (3,5-di-t-butyl-4-hydroxy) benzoate, hexadecyl (3,5 -Di-t-butyl-4-hydroxy) benzoate, octadecyl (3,5-di-t-butyl-4-hydroxy) benzoate, behenyl (3,5-di-t-butyl-4-hydroxy) benzoate, stearyl (3,5-di-t-butyl-4-hydroxybenzoate).

<Wavelength conversion particles and production method thereof>
In the present invention, the fluorescent substance is preferably used in the form of particles coated with a transparent material. The particles include (a) a fluorescent substance, (b) a transparent material, and (c) a light stabilizer, and the transparent material usually contains the fluorescent substance. The shape of the particles varies depending on the production method, but is preferably spherical from the viewpoint of dispersibility in the sheet.

  When the wavelength conversion particle of the present invention is coated with a transparent material containing a light stabilizer, stability such as light resistance is improved, an expensive fluorescent material, and a rare earth metal complex having low moisture resistance are used. Use efficiency can be maximized.

Moreover, although the magnitude | size of wavelength conversion particle | grains can be suitably selected according to the objective, when using for an agricultural wavelength conversion sheet, it is preferable to set it as 0.05-0.5 micrometer, for example, 0.1-0. More preferably, it is 2 μm.
There is no restriction | limiting in particular as content of the fluorescent substance in the wavelength conversion particle | grains of this invention, Although it can select suitably according to the objective and the kind of fluorescent substance, it is 0.001-1 mass% from a viewpoint of wavelength conversion efficiency. It is preferable that it is 0.01-0.5 mass%.

<(B) Transparent material>
In the present invention, (a) the fluorescent substance and (c) the light stabilizer are contained in (b) the transparent material. In the present invention, the term “transparent” means that the transmittance of light having a wavelength of 400 to 800 nm at an optical path length of 1 cm is 90% or more.
The transparent material is not particularly limited as long as it is transparent, and examples thereof include resins such as acrylic resin, methacrylic resin, urethane resin, epoxy resin, polyester resin, polyethylene resin, and polyvinyl chloride resin. Among these, acrylic resins and methacrylic resins are preferable. Although there is no restriction | limiting in particular as a monomer compound which comprises the said resin, It is preferable that a vinyl compound is included at least.

  In addition, as a method of incorporating the (a) fluorescent substance and (c) light stabilizer in the (b) transparent material, the fluorescent substance and light stabilizer are dissolved in a monomer compound (monomer composition) or It can be obtained by a method obtained by dispersing and polymerizing the solution (bulk polymerization, suspension polymerization, emulsion polymerization, solution polymerization), a casting method, a melting method, and the like. Turbid polymerization and emulsion polymerization are preferred. Furthermore, the resin composition can be pulverized and classified as necessary to obtain particles having a desired size.

(Vinyl compound)
In the present invention, the vinyl compound is not particularly limited as long as it is a compound having at least one ethylenically unsaturated bond, and an acrylic monomer, a methacrylic monomer, which can be converted into a vinyl resin, particularly an acrylic resin or a methacrylic resin when polymerized. (Meth) acrylic acid derivatives such as acrylic oligomers and methacrylic oligomers can be used without particular limitation. In the present invention, an acrylic monomer, a methacryl monomer, and the like are preferable.

  Preferred acrylic monomers and methacrylic monomers as (meth) acrylic acid derivatives include, for example, acrylic acid, methacrylic acid, and alkyl esters thereof, and in combination with other vinyl compounds that can be copolymerized therewith. It can also be used alone or in combination of two or more. Here, the following (meth) acrylic acid means acrylic acid, methacrylic acid or a mixture thereof. (Meth) acrylate means acrylate, methacrylate or mixtures thereof.

  As (meth) acrylic acid alkyl ester, (meth) acrylic acid unsubstituted alkyl ester such as methyl (meth) acrylate, ethyl (meth) acrylate, butyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, etc. Dicyclopentenyl (meth) acrylate; tetrahydrofurfuryl (meth) acrylate; benzyl (meth) acrylate; a compound obtained by reacting a polyhydric alcohol with an α, β-unsaturated carboxylic acid (for example, polyethylene glycol di (meta) ) Acrylate (having 2 to 14 ethylene groups), trimethylolpropane di (meth) acrylate, trimethylolpropane tri (meth) acrylate, trimethylolpropane ethoxytri (meth) acrylate, trimethylolpropane propoxytri (meta) ) Acrylate, tetramethylol methane tri (meth) acrylate, tetramethylol methane tetra (meth) acrylate, polypropylene glycol di (meth) acrylate (having 2 to 14 propylene groups), dipentaerythritol penta (meth) acrylate, di Pentaerythritol hexa (meth) acrylate, bisphenol A polyoxyethylene di (meth) acrylate, bisphenol A dioxyethylene di (meth) acrylate, bisphenol A trioxyethylene di (meth) acrylate, bisphenol A deoxyoxyethylene di (meth) Acrylate); a compound obtained by adding an α, β-unsaturated carboxylic acid to a glycidyl group-containing compound (for example, trimethylolpropane triglycidyl ether triacrylate) Bisphenol A diglycidyl ether diacrylate); an esterified product of a polyvalent carboxylic acid (for example, phthalic anhydride) and a substance having a hydroxyl group and an ethylenically unsaturated group (for example, β-hydroxyethyl (meth) acrylate); Urethane (meth) acrylate (for example, reaction product of diisocyanate and hydroxyl group-containing (meth) acrylate ester, reaction product of tolylene diisocyanate and 2-hydroxyethyl (meth) acrylate, trimethylhexamethylene diisocyanate and cyclohexanedimethanol and 2 -Reaction product with hydroxyethyl (meth) acrylate); (meth) acrylic acid-substituted alkyl esters in which a hydroxyl group, an epoxy group, a halogen group, or the like is substituted on these alkyl groups.

  Examples of other vinyl compounds that can be copolymerized with (meth) acrylic acid and (meth) acrylic acid alkyl esters include acrylamide, acrylonitrile, diacetone acrylamide, styrene, and vinyl toluene. These vinyl monomers can be used alone or in combination of two or more.

The vinyl compound in the present invention can be appropriately selected so that the refractive index of the resin particles to be formed has a desired value, and at least one selected from an alkyl acrylate ester and an alkyl methacrylate ester is used. preferable. In addition, since the particles can be cross-linked and the characteristics of the particles can be changed, it is preferable to use a bifunctional or higher functional vinyl compound in combination.
Further, it is preferable to use a vinyl monomer having a light stabilizing function as the vinyl compound. A vinyl monomer having a photostabilization function is a compound having a double bond to the above photostabilizer, for example, hindered amine antioxidant 4-methacryloyloxy-1,2,2,6,6-pentamethylpiperidine is Can be mentioned. When this is used for polymerization, a light stabilizer is incorporated into the transparent resin, and the stabilizer is not diffused from the wavelength conversion particles into the agricultural wavelength conversion sheet, thereby reducing the concentration of the stabilizer in the wavelength conversion particles. Sustainability increases because it brings about an effect.
A vinyl monomer having a light stabilizing function can be obtained by reacting a vinyl monomer having a reactive functional group such as a hydroxyl group, an epoxy group, a carboxyl group, or an isocyanate group with a reactive functional group of a light stabilizer. .

(Radical polymerization initiator)
In the present invention, it is preferable to use a radical polymerization initiator in order to polymerize a vinyl compound to form a transparent material. As the radical polymerization initiator, a commonly used radical polymerization initiator can be used without particular limitation. Preferred examples of the radical polymerization initiator include peroxides. Specifically, persulfates that generate free radicals by heat, organic peroxides, and azo radical initiators are preferable.
Examples of persulfates include potassium persulfate, ammonium persulfate, and sodium persulfate.
Organic peroxides include isobutyl peroxide, α, α'-bis (neodecanoylperoxy) diisopropylbenzene, cumylperoxyneodecanoate, di-n-propylperoxydicarbonate, bis-s-butyl. Peroxydicarbonate, 1,1,3,3-tetramethylbutylneodecanoate, bis (4-t-butylcyclohexyl) peroxydicarbonate, 1-cyclohexyl-1-methylethylperoxyneodecanoate, Bis-2-ethoxyethyl peroxydicarbonate, bis (ethylhexylperoxy) dicarbonate, t-hexyl neodecanoate, bismethoxybutyl peroxydicarbonate, bis (3-methyl-3-methoxybutylperoxy) di Carbonate, t-butylperoxyne Decanoate, t-hexylperoxypivalate, 3,5,5-trimethylhexanoyl peroxide, octanoyl peroxide, lauroyl peroxide, stearoyl peroxide, 1,1,3,3-tetramethylbutylperoxy-2 -Ethylhexanoate, succinic peroxide, 2,5-dimethyl-2,5-bis (2-ethylhexanoyl) hexane, 1-cyclohexyl-1-methylethylperoxy-2-ethylhexanoate, t -Hexylperoxy-2-ethylhexanoate, 4-methylbenzoyl peroxide, t-butylperoxy-2-ethylhexanoate, m-toluonoylbenzoyl peroxide, benzoyl peroxide, t-butylperoxyiso Butyrate, 1,1 Bis (t-butylperoxy) 2-methylcyclohexane, 1,1-bis (t-hexylperoxy) -3,3,5-trimethylcyclohexane, 1,1-bis (t-hexylperoxy) cyclohexane, , 1-bis (t-butylperoxy) -3,3,5-trimethylcyclohexane, 1,1-bis (t-butylperoxy) cyclohexanone, 2,2-bis (4,4-dibutylperoxycyclohexyl) Propane, 1,1-bis (t-butylperoxy) cyclododecane, t-hexylperoxyisopropyl monocarbonate, t-butylperoxymaleic acid, t-butylperoxy-3,5,5-trimethylhexanoate , T-butyl peroxylaurate, 2,5-dimethyl-2,5-bis (m-toluoyl peroxy ) Hexane, t-butylperoxyisopropyl monocarbonate, t-butylperoxy-2-ethylhexyl monocarbonate, t-hexylperoxybenzoate, 2,5-dimethyl-2,5-bis (benzoylperoxy) hexane, t -Butylperoxyacetate, 2,2-bis (t-butylperoxy) butane, t-butylperoxybenzoate, n-butyl-4,4-bis (t-butylperoxy) valerate, di-t-butyl Peroxyisophthalate, α, α'-bis (t-butylperoxy) diisopropylbenzene, dicumyl peroxide, 2,5-dimethyl-2,5-di (t-butylperoxy) hexane, t-butyl cumi Ruperoxide, p-menthane hydroperoxide, 2,5-dimethyl-2, -Bis (t-butylperoxy) hexyne, diisopropylbenzene hydroperoxide, t-butyltrimethylsilyl peroxide, 1,1,3,3-tetramethylbutyl hydroperoxide, cumene hydroperoxide, t-hexyl hydroperoxide , T-butyl hydroperoxide, 2,3-dimethyl-2,3-diphenylbutane, and the like can be used.

  As the azo radical initiator, azobisisobutyronitrile (AIBN, trade name V-60, manufactured by Wako Pure Chemical Industries, Ltd.), 2,2′-azobis (2-methylisobutyronitrile) (trade name) V-59, manufactured by Wako Pure Chemical Industries, Ltd.), 2,2′-azobis (2,4-dimethylvaleronitrile) (trade name V-65, manufactured by Wako Pure Chemical Industries, Ltd.), dimethyl-2,2 ′ -Azobis (isobutyrate) (trade name V-601, manufactured by Wako Pure Chemical Industries, Ltd.), 2,2'-azobis (4-methoxy-2,4-dimethylvaleronitrile) (trade name V-70, Wako Pure Chemical) Kogyo Co., Ltd.).

  The usage-amount of a radical polymerization initiator can be suitably selected according to the kind of said vinyl compound, the refractive index of the resin particle formed, etc., and is used by the usage-amount normally used. Specifically, for example, it can be used at 0.01 to 2% by weight, preferably 0.1 to 1% by weight, based on the vinyl compound.

  Hereinafter, the present invention will be described more specifically by way of examples. However, the present invention is not limited to these examples. Unless otherwise specified, “%” and “part” are based on mass.

<Example 1>
(Production of wavelength conversion particles)
Eu (TTA) ₃ (PH ₃ PO) ₂ (excitation maximum wavelength 340 nm, emission maximum wavelength 630 nm) 0.5 g as component (a) fluorescent substance, methyl methacrylate (monomer) as transparent material (b) Component) 94.0 g, ethylene glycol dimethacrylate (crosslinking agent) 5.0 g, pentamethylpiperidinyl methacrylate (4-methacryloyloxy-1,2,2,6,6-pentamethylpiperidine, funcryl FA-77, A monomer solution was prepared by dissolving in 1.0 g of Hitachi Chemical Co., Ltd. (hindered amine antioxidant, light stabilizer). Pentamethylpiperidinyl methacrylate serves as both the transparent material (b) and the light stabilizer (c), and is incorporated into the transparent material.
This monomer solution was put into 440.0 g of an aqueous solution containing 1.0 g of sodium dodecylbenzenesulfonate (surfactant), and then stirred with a stirring blade to obtain an emulsion. The emulsion was stirred with a stirring blade at 140 rotations / minute (rpm), and after bubbling with nitrogen at room temperature (25 ° C.) for 1 hour, the temperature was raised to 60 ° C. in a nitrogen stream, and 0.5% 10.0 g of an aqueous potassium persulfate solution was added and polymerized at 60 ° C. for 6 hours. After the polymerization, the mixture was cooled to room temperature to obtain a latex liquid. This latex solution was gently poured into 500.0 g of a 10% aqueous sodium sulfate solution, and particles were precipitated by salting out. The precipitate was separated by filtration, dried at 60 ° C. for 24 hours, and pulverized to obtain wavelength conversion particles having an average diameter of 0.1 μm.

(Production of sheet)
5.0 g of the above particles were mixed with 90.0 g of HAD1004B (base resin, acrylic polyol having a hydroxyl value of 130 mgKOH / g, solid content: 50%, solvent: butyl acetate, manufactured by Hitachi Chemical Co., Ltd.), Sumidur N3300 (curing agent, hexa It was dispersed in 10.0 g of an isocyanurate structure of methylene diisocyanate (manufactured by Sumika Bayer Urethane Co., Ltd.) to prepare a resin compounding liquid. This resin compounded solution is coated on a PET film using a 500 μm applicator, dried at 60 ° C. for 12 hours and 120 ° C. for 1 hour, peeled off from the PET film, and dispersed with wavelength conversion particles having a thickness of 120 μm. Got.

(Measurement of wavelength conversion ability of sheet)
The emission intensity of a wavelength of 630 nm when the obtained sheet was irradiated with light having a wavelength of 340 nm was measured using a fluorescence spectrophotometer F-2700 (manufactured by Hitachi High-Tech Science Co., Ltd.). After the measurement, it was exposed to the outdoors for 720 hours, and the emission intensity was measured in the same manner. The results are shown in Table 1.

<Comparative Example 1>
(Production of sheet)
Eu (TTA) ₃ (PH ₃ PO) ₂ 0.025 g, HAD1004B (base resin, solid content: 50%, solvent: butyl acetate, manufactured by Hitachi Chemical Co., Ltd.) 90.0 g, Sumidur N3300 (curing agent, Residential The resin compounding liquid was produced by dispersing in 10.0 g. This resin compounded solution was applied onto a PET film using a 500 μm applicator, dried at 60 ° C. for 12 hours and 120 ° C. for 1 hour, and the PET film was peeled off to obtain a sheet having a thickness of 120 μm.

(Measurement of wavelength conversion ability of sheet)
The emission intensity of the obtained sheet was measured in the same manner as in Example 1. The results are shown in Table 1.

  Example 1 in which the phosphor was coated with a transparent material containing a light stabilizer and contained in the sheet was Comparative Example 1 in which the same amount of phosphor as in Example 1 was contained in the sheet without coating. As compared with the above, it was confirmed that the emission intensity after 720 hours of outdoor exposure was high and the stability was excellent.

Claims (9)

  A wavelength conversion particle used by adding to an agricultural wavelength conversion sheet for converting a short wavelength component of irradiation light into a long wavelength component, wherein (a) one or more fluorescent substances, (b) a transparent material, (c) ) A wavelength converting particle comprising a light stabilizer.   The wavelength according to claim 1, wherein (a) the fluorescent material is a fluorescent material that emits light by converting a short wavelength component to a long wavelength component, an excitation maximum wavelength is 400 nm or less, and an emission maximum wavelength is 400 nm to 700 nm. Conversion particles.   The wavelength conversion particle according to claim 1 or 2, wherein the fluorescent material (a) is an organic phosphor or a rare earth metal complex.   The wavelength conversion particle according to any one of claims 1 to 3, wherein the transparent material (b) is a transparent resin.   The wavelength conversion particle according to any one of claims 1 to 4, wherein the transparent material (b) is a transparent vinyl resin.   The wavelength conversion particle according to any one of claims 1 to 5, wherein the (b) transparent material is a transparent (meth) acrylic resin.   The wavelength conversion particle according to any one of claims 1 to 6, wherein the (c) light stabilizer is a hindered amine light stabilizer.   The wavelength conversion particles are emulsion-polymerized or suspension-polymerized by dissolving or dispersing (a) one or more kinds of fluorescent substances and (c) a light stabilizer in (b) a vinyl monomer composition serving as a transparent material. The wavelength conversion particle according to any one of claims 1 to 7, which is a resin particle.   The wavelength conversion according to any one of claims 1 to 8, wherein (c) the light stabilizer is a vinyl monomer having a light stabilizing function, and is emulsion-polymerized or suspension-polymerized, and (b) is incorporated into the transparent material. particle.