JP6656619B2 - Photocurable composition and cured product - Google Patents

Description

  The present invention relates to a photocurable composition containing a heteropolyacid containing tungsten and / or molybdenum and a photocurable resin, and a cured product obtained by complexing a heteropolyacid and a cured photocurable resin.

  Refractive index is one of the properties of a substance. The refractive index is greatly affected by the constituent elements, molecular structure, crystal structure, and charge, and the modulation of the refractive index is not easy. Normally, the refractive index of a polymer made of an organic compound is limited to around 1.4 to 1.6, and lacks variations compared to inorganic materials of 0.17 (silver) to 4.2 (silicon). This is because the main component of the polymer is mainly carbon having low atomic refraction. However, in order to utilize the moldability and / or lightness of the polymer, in the use of an optical material such as a lens, an attempt to increase the refractive index of the polymer material by molecular design such as introduction of a sulfur atom and / or a bromine atom. Has been done. In addition, refractive index modulation is also performed by combining a polymer material with metal oxide fine particles having a high refractive index. This is because the refractive index modulation of a functional polymer cannot be achieved by changing the constituent elements. The metal oxide used includes alumina, titania, zirconia and the like (for example, see Patent Document 1). However, in order to enhance the transparency of the composite material, it is necessary to uniformly disperse metal oxide fine particles having a particle size of several nm in the composite material. Therefore, it is not easy to produce a composite material containing metal oxide fine particles.

  In order to solve the above problems, a method for easily producing a composite of tungstic acid and / or molybdic acid and a polymer, and high transparency and a desired refractive index obtained by the method, are obtained. Has been proposed (see Patent Document 2).

JP-A-9-221598 WO 2013/191130

  However, when photo-curing a composite of tungstic acid and / or molybdic acid and a polymer, sufficient curability is not obtained even when irradiated with light, and a cured product may not be formed in some cases. The present invention has been made to solve this problem, and an object of the present invention is to provide a photocurable composition having sufficient curability and a wide adjustment range of refractive index.

  The photocurable composition of the first embodiment of the present invention comprises (a) one or more heteropolyacid compounds, (b) one or more polymerizable compounds, and (c) one or more Comprising a plurality of types of photopolymerization initiator, the heteropolyacid compound is selected from the group consisting of a heteropolyacid containing tungsten and a salt thereof, and a heteropolyacid containing molybdenum and a salt thereof, and the photopolymerization initiator is It is characterized by having absorption for light having a wavelength of 400 nm or more. The photocurable composition of this embodiment may further include (d) one or more solvents. Here, it is preferable that the boiling point of the solvent under normal pressure is 250 ° C. or less, and the solvent is liquid at normal temperature. Further, the content of the heteropolyacid compound (a) may be 50 to 95% by mass based on the mass of the photocurable composition excluding the component (d).

  The cured product of the second embodiment of the present invention is obtained by irradiating the photocurable composition of the first embodiment with light.

  By employing the above configuration, it is possible to impart sufficient curability to the photocurable composition containing the heteropolyacid of tungsten and / or molybdenum to form a cured product. Further, in the obtained cured product, the refractive index can be adjusted in a wide range.

  In addition, the cured product employing the above configuration is a microlens array used for CCD, C-MOS sensor, etc .; a light scattering layer used for lighting and display; a light emitting element (organic EL element, light emitting diode (LED), semiconductor Antireflection layer (film) used in displays, photovoltaic cells, optical filters, etc .; optical waveguide resists; display elements utilizing photonic structures; distributed reflection (DBR) or distributed feedback (DFB) lasers It can be used as a light confining material used for an element; a scatterer of a random laser oscillation element;

4 is a graph showing the relationship between the content of a heteropolyacid compound in a cured product and the refractive index of the cured product.

  The photocurable composition of the first embodiment of the present invention comprises (a) one or more heteropolyacid compounds, (b) one or more polymerizable compounds, and (c) one or more Comprising a plurality of types of photopolymerization initiator, the heteropolyacid compound is selected from the group consisting of a heteropolyacid containing tungsten and a salt thereof, and a heteropolyacid containing molybdenum and a salt thereof, and the photopolymerization initiator is It is characterized by having absorption for light having a wavelength of 400 nm or more.

  In the present embodiment, the heteropolyacid compound (a) is not dispersed in the photocurable composition as particles, but is present uniformly in a state dissolved in the photocurable composition. By irradiating the photocurable composition of this embodiment with light, a cured product in which the heteropolyacid compound (a) is uniformly present can be obtained.

  The photopolymerization initiator contained in the photocurable composition of the present invention has absorption for light having a wavelength of 400 nm or more, and is polymerizable when irradiated with light having a wavelength of 400 nm or more (b). To initiate polymerization. Light having a wavelength of less than 400 nm is blocked by the heteropolyacid compound (a). Therefore, in the composition containing the heteropolyacid compound (a), a photopolymerization initiator that does not absorb light having a wavelength of 400 nm or more cannot initiate polymerization even when irradiated with light. As a result, a composition containing a photopolymerization initiator that does not absorb light having a wavelength of 400 nm or more cannot have sufficient photocurability.

(A) Heteropolyacid compound The heteropolyacid compound used in the present embodiment is selected from the group consisting of a heteropolyacid containing tungsten and a salt thereof, and a heteropolyacid containing molybdenum and a salt thereof. Non-limiting examples of heteropolyacids including tungsten and heteropolyacids including molybdenum include silicotungstic acid (such as H ₄ [SiW ₁₂ O ₄₀ ]), phosphotungstic acid (such as H ₃ [PW ₁₂ O ₄₀ ]), silicon molybdic acid (such as _{H 4 [SiMo 12 O 40]} ), ( such as _{H 3 [PMo 12 O 40]} ) phosphomolybdic acid, phosphoric tongue strike molybdic acid (such as _{H 3 [PW 12-x Mo} x O 40]), and Includes phosphorus vanado molybdic acid (H ₃ [PV _12-x Mo _x O ₄₀ ], etc.). Specific examples of the salts of these heteropoly acids include alkali metal salts such as sodium and potassium, and ammonium salts. Further, the above-mentioned heteropolyacid and its salt may be a hydrate, or may be a form having a low content of anhydride or water of crystallization obtained by heat-treating the hydrate. In the present embodiment, one of the above-mentioned heteropoly acids or salts thereof may be used, or two or more heteropoly acids or salts thereof may be used in combination.

  By adjusting the content of the heteropolyacid compound (a), the refractive index of the cured product can be adjusted. The content of the heteropolyacid compound (a) is typically 50 to 95% by mass based on the mass of the photocurable composition excluding the solvent (d). By setting the content within such a range, it is possible to prevent an increase in cost and embrittlement of the cured product, and to adjust the refractive index of the cured product in a range higher than the range that can be adjusted with a general-purpose acrylate resin. It becomes possible. When a hydrate is used as the heteropolyacid compound (a), the mass of hydration water is excluded from the mass of the heteropolyacid compound (a) and the total mass of the composition. That is, the content of the heteropolyacid compound (a) is calculated by the following equation.

  Furthermore, the content of the heteropolyacid compound (a) in the cured product after photocuring can be determined by thermal mass spectrometry-differential thermal analysis (TG-DTA) in which the cured product is heated to 550 ° C. in the presence of oxygen. . By performing TG-DTA under the above conditions, the mass of the remaining water of hydration and the solvent (d), the mass of the resin component derived from the polymerizable compound (b) and the photopolymerization initiator (c), The mass of the heteropolyacid or a salt thereof (excluding water of hydration) in the heteropolyacid compound (a) can be clearly distinguished and quantified.

(B) Polymerizable compound The polymerizable compound used in the present embodiment contains a polyfunctional component having two or more ethylenic carbon-carbon double bonds per molecule. Preferred examples of multifunctional components include acrylates or methacrylates having two or more ethylenic carbon-carbon double bonds per molecule. Here, the ethylenic carbon-carbon double bond desirably exists in the form of an acryl group or a methacryl group. Hereinafter, “acrylate” and “methacrylate” are collectively referred to as “(meth) acrylate”. Alternatively, a compound other than (meth) acrylate having two or more ethylenic carbon-carbon double bonds per molecule may be used as the polyfunctional component. Furthermore, as long as sufficient curability is obtained, the polymerizable compound may include a monofunctional component having one ethylenic carbon-carbon double bond per molecule.

  The polymerizable compound can be appropriately selected from known materials, provided that the heteropolyacid compound (a) can be uniformly dispersed or dissolved. For example, non-limiting examples of polyfunctional components that can be used include the following materials.

(I) Bifunctional (meth) acrylate Alkanediol di (meth) acrylate, polyethylene glycol di (meth) acrylate, polypropylene glycol di (meth) acrylate, N, N'-methylenebis (meth) acrylamide, bisphenol A di (meth) ) Acrylate.

(Ii) Trifunctional or higher-functional (meth) acrylate trimethylolpropane tri (meth) acrylate, ethylene oxide (EO) -modified trimethylolpropane tri (meth) acrylate, pentaerythritol tri (meth) acrylate, pentaerythritol tetra (meth) acrylate , Dipentaerythritol penta (meth) acrylate, dipentaerythritol hexa (meth) acrylate, and tris (2- (meth) acryloyloxyethyl) isocyanurate.

  Alternatively, divinylbenzene, diallylbenzene, trivinylbenzene, divinylcyclohexane, diallylcyclohexane, bisphenol A diallyl ether, triallyl isocyanurate, or the like may be used as the polyfunctional component.

  Also, non-limiting examples of monofunctional components that can be used include the following materials.

2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 2-hydroxybutyl (meth) acrylate;
n-butyl (meth) acrylate, isobutyl (meth) acrylate, t-butyl (meth) acrylate, cyclohexyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, isobornyl (meth) acrylate, isodecyl (meth) acrylate, lauryl ( (Meth) acrylate, tridecyl (meth) acrylate, cetyl (meth) acrylate, stearyl (meth) acrylate, benzyl (meth) acrylate;
Glycidyl (meth) acrylate, acryloyl morpholine, tetrahydrofurfuryl (meth) acrylate, 2-ethoxyethyl (meth) acrylate, 3-methoxybutyl (meth) acrylate, methoxydiethylene glycol (meth) acrylate, methoxypolyethylene glycol (meth) acrylate Methoxypropylene glycol (meth) acrylate, 2- (meth) acryloyloxyethyl-2-hydroxypropyl phthalate, 2-hydroxy-3-phenoxypropyl (meth) acrylate, ethyl carbitol (meth) acrylate;
Dimethylaminoethyl (meth) acrylate;
Trifluoroethyl (meth) acrylate, tetrafluoropropyl (meth) acrylate, hexafluoropropyl (meth) acrylate, octafluoropropyl (meth) acrylate, octafluoropropyl (meth) acrylate;
Adamantyl (meth) acrylate derived from 2-adamantane or adamantanediol and having one mono (meth) acrylate;
Phosphorylated alkyl (meth) acrylate, EO-modified phosphorylated alkyl (meth) acrylate.

  Alternatively, the polymerizable compound may further include a polymerizable oligomer or a polymerizable polymer. Examples of the polymerizable oligomer include an epoxy oligomer having an ethylenic carbon-carbon double bond in a side chain, a urethane oligomer having an ethylenic carbon-carbon double bond in a side chain, and an ethylenic carbon-carbon double bond in a side chain. Includes polyester oligomers containing heavy bonds. Examples of the polymer having polymerizability include various polymers having an ethylenic carbon-carbon double bond in a side chain.

  The polymerizable compound of this embodiment may be composed of one kind of polyfunctional component. Alternatively, the polymerizable compound of this embodiment may include at least one polyfunctional component, at least two polyfunctional components, a monofunctional component, a polymerizable oligomer, and / or a polymerizable compound. It may be a mixture of polymers having properties.

(C) Photopolymerization initiator The photocurable composition of this embodiment contains one or more photopolymerization initiators that absorb light having a wavelength of 400 nm or more. In the present specification, "having absorption for light having a wavelength of 400 nm or more" means that the absorbance is 0.2 or more when a 0.1% by mass acrylonitrile solution is measured with an optical path length of 1 cm. It means that the wavelength exists in a region of 400 nm or more. The photopolymerization initiator generates a radical when irradiated with light containing a component that achieves the above absorbance. The photopolymerization initiator that can be used can be appropriately selected from acetophenones, benzoins, benzophenones, phosphine oxides, ketals, anthraquinones, thioxanthones, and the like. Non-limiting examples of photoinitiators having absorption for light having a wavelength of 400 nm or more include 2,4,6-trimethylbenzoyl-diphenyl-phosphine oxide, bis (2,4,6-trimethylbenzoyl) -Phenylphosphine oxide, 2-benzyl-2-dimethylamino-1- (4-morpholinophenyl) -1-butanone.

  The photocurable composition of the present embodiment is typically 0.1 to 20 parts by mass, preferably 1 to 10 parts by mass, based on 100 parts by mass of the polymerizable compound (b). (C).

(D) Solvent The photocurable composition of the present embodiment may further contain a solvent for the purpose of viscosity adjustment or the like. Solvents that can be used have a boiling point of 250 ° C. or lower at normal pressure (atmospheric pressure) and include compounds that are liquid at normal temperature (25 ° C.). Further, the solvent is required to be able to dissolve the material used for the photocurable composition. Non-limiting examples of solvents that can be used are:
water;
Ethers such as dibutyl ether, dimethoxymethane, dimethoxyethane, diethoxyethane, propylene oxide, dioxane, dioxolan, trioxane, tetrahydrofuran, anisole and phenetole;
Ketones such as acetone, methyl ethyl ketone, diethyl ketone, methyl isobutyl ketone, dipropyl ketone, diisobutyl ketone, cyclopentanone, cyclohexanone and methylcyclohexanone;
Esters such as ethyl formate, propyl formate, n-pentyl formate, methyl acetate, ethyl acetate, methyl propionate, ethyl propionate, n-pentyl acetate, 2-ethoxyethyl acetate, and γ-butyrolactone;
Alcohols such as ethanol, isopropyl alcohol, 2-methoxyethanol, 2-ethoxyethanol and 2-butoxyethanol; and amides such as dimethylformamide and dimethylacetamide.

  In this embodiment, one kind of solvent may be used, or a mixture of two or more kinds of solvents may be used.

(E) Additives The photocurable composition of this embodiment may further include any additive known in the art to which the desired use belongs. Additives that can be used include, for example, photosensitizers, chain transfer agents, surface conditioners, antioxidants, adhesion improvers, release agents, and the like.

  The cured product of the second embodiment of the present invention is formed by irradiating the photocurable composition of the first embodiment with light.

  The cured product of the present embodiment is formed by a method including (1) a step of forming a film of the photocurable composition, and (2) a step of irradiating the film of the photocurable composition with light. If necessary, a step (1 ') of drying the film of the photocurable composition may be performed between the steps (1) and (2). After the step (2), a step (3) of annealing the cured product may be performed. Hereinafter, each step will be described.

(1) Step of Forming Photocurable Composition Film This step can be performed using any technique known in the art, such as coating, casting, casting (casting), and extrusion. .

  When this step is performed using coating, a roll coater, a reverse roll coater, a gravure coater, a microgravure coater, a knife coater, a bar coater, a wire bar coater, a die coater, a dip coater, or the like can be used. Here, a single-wafer method in which a photocurable composition is applied to a sheet-shaped substrate may be used, or the photocurable composition is applied to a roll-shaped substrate, and subsequently, the substrate is wound around a roll. A take-up roll-to-roll system may be used. When the roll-to-roll method is used, a step (2) of irradiating the film of the photocurable composition with light, which will be described later, is performed between the coating and the winding, and the cured product is formed before the winding. May be formed. In particular, it is preferable to use a roll-to-roll method. Because, in the roll-to-roll system, the base material is continuously moved from the unwinding section (supply section) to the winding section via the coating section and optionally the light irradiation section. This is because a film of the photocurable composition or cured product can be manufactured continuously. When the roll-to-roll method is used, the substrate typically has a thickness of 25 μm or more and 200 μm or less, preferably 40 μm or more and 80 μm or less.

  When this step is performed using a casting, the surface of the finally obtained cured product can be formed with irregularities by imparting irregularities to the surface of the mold. In addition, using a mold formed of a material that is transparent to light having a wavelength of 400 nm or more, the step of (2) irradiating the film of the photocurable composition with light in the mold may be performed. Good.

  The substrate used in this step includes any material known in the art. Non-limiting examples of materials that make up the substrate include glass, silicon, and thermoplastic materials such as polyethylene, polymethyl methacrylate, polyethylene terephthalate. Alternatively, depending on the use of the cured product, the substrate may have various functional components formed on the aforementioned materials. For example, an organic EL element, various laser elements, a photovoltaic cell, a light receiving element, and the like formed on a silicon wafer may be used as a base material in this step.

(1 ′) Step of drying the film of the photocurable composition If necessary, a step of drying the film of the photocurable composition is provided between the step (1) and the step (2) described below. Is also good. In particular, when the photocurable composition contains a solvent, it is useful for distilling off the solvent. This step includes, for example, a method of passing a film of the photocurable composition through a drying oven, a method of blowing dry air on the film of the photocurable composition, a method of heating the film of the photocurable composition, and the like. It can be implemented in any way known in the art. Drying ovens that can be used include a radial drying oven, a circulating air drying oven, and the like. A hot air blower or the like can be used for forming the drying air. For heating the film of the photocurable composition, a heating roll, an infrared heater, or the like can be used.

(2) Step of irradiating the film of the photocurable composition with light Subsequently, the film of the photocurable composition is irradiated with light to cause photocuring to form a cured product. In this step, any light source known in the art can be used, provided that light having a wavelength of 400 nm or more can be irradiated with sufficient intensity. Light sources that can be used include high-pressure mercury lamps, low-pressure mercury lamps, ultra-high-pressure mercury lamps, metal halide lamps, carbon arc lamps, xenon arc lamps, and the like.

  Here, when it is required to form a predetermined pattern such as irregularities on the surface of the cured product, light is irradiated while a stamper having an inverted shape of the predetermined pattern is pressed against the film of the photocurable composition. May be. When the stamper is formed of a material that transmits light having a wavelength of 400 nm or more, light irradiation may be performed through the stamper. After the photocuring is completed, a predetermined pattern can be obtained by removing the stamper. If the photocurable composition itself has sufficient consistency to maintain its shape after removing the stamper, light may be applied after removing the stamper.

  Alternatively, when it is required to form a cured product only in a partial region on the base material, light may be irradiated through a photomask having a predetermined pattern. Subsequent to the light irradiation, the photocurable composition in a region not irradiated with the light can be removed by washing with a solvent or the like. On the other hand, in a region irradiated with light, photo-curing proceeds to obtain a cured product. This method is particularly effective when a cured product is formed only at a predetermined position on a substrate including a functional component.

(3) Step of annealing the cured product The cured product of the present embodiment may be annealed. “Annealing” in the present invention means a process of heating an object to an appropriate temperature, maintaining the temperature of the object for a predetermined time, and thereafter gradually cooling the object. The heating temperature may be, for example, in the range of 50C to 200C. Further, the time for keeping the target at the above-mentioned heating temperature may be, for example, in a range of 5 minutes to 120 minutes.

  Annealing is useful for increasing the hardness of the cured product, improving the water resistance, and improving the solvent resistance.

  The cured product obtained by the method described above can have a refractive index in a range higher than the adjustable range (about 1.4 to 1.6) of the general-purpose acrylate resin. The refractive index can be adjusted by changing the content of the heteropolyacid compound (a). More specifically, the cured product of this embodiment can have a refractive index in the range of about 1.55 to about 1.80.

  Therefore, the cured product of the present embodiment is useful in applications requiring a high refractive index and / or high moldability. For example, the cured product of the present embodiment is a microlens array used for a CCD or a C-MOS sensor; a light scattering layer used for lighting and a display; a light emitting element (organic EL element, light emitting diode (LED), semiconductor laser, ), Antireflection layers (films) used in displays, photovoltaic cells, optical filters, etc .; optical waveguide resists; display elements utilizing photonic structures; distributed reflection (DBR) type or distributed feedback (DFB) type laser elements It is believed that the present invention can be applied to a light confining material used; a scatterer of a random type laser oscillation element;

(Example 1)
The following materials were mixed to prepare a photocurable composition.
(A) Heteropolyacid compound Silicotungstic acid 26 hydrate (SiW12, Wako Pure Chemical Industries, Ltd.) 69.9 parts by mass (b) Polymerizable compound;
38.0 parts by mass of trimethylolpropane triacrylate (TMPTA, Osaka Organic Chemical Industry Co., Ltd.); and (c) photopolymerization initiator 2,4,6-trimethylbenzoyl-diphenyl-phosphine oxide (Lucirin TPO, manufactured by BASF) 2.0 parts by mass.

  If the material was difficult to dissolve, it was heated to 50-60 ° C to completely dissolve. Excluding hydration water, the content of the heteropolyacid compound (a) in the above composition was 60% by mass. In addition, 2,4,6-trimethylbenzoyl-diphenyl-phosphine oxide had absorption for light having a wavelength of 400 nm or more.

The obtained photocurable composition was applied on a glass substrate using a wire bar coater. The coating amount of the composition was adjusted so that the film thickness after curing was 7 μm. Subsequently, the film of the photocurable composition was irradiated with light from a high-pressure mercury lamp using a conveyor-type ultraviolet curing device to obtain a cured film. The light irradiation amount was 300 mJ / cm ² .

(Examples 2, 3, and 8)
The composition of the photocurable composition was changed to the composition containing the solvent shown in Table 1 and that drying was performed in an oven at 50 ° C. for 1 minute following application using a wire bar coater. Except for this, the procedure of Example 1 was repeated to obtain a cured film.

  Examples 2, 3 and 8 relate to photocurable compositions using ethyl acetate as solvent. Further, in Example 3, the photopolymerization initiator was changed to bis (2,4,6-trimethylbenzoyl) -phenylphosphine oxide having absorption for light having a wavelength of 400 nm or more.

(Examples 4 to 7 and 9, Comparative Examples 1 and 2)
A cured film was obtained by repeating the procedure of Example 1 except that the composition of the photocurable composition was changed to a composition containing a solvent shown in Table 1.

  In Example 9, phosphotungstic acid 30 hydrate was used as the heteropolyacid compound instead of silicotungstic acid 26 hydrate. In Comparative Example 1, the photopolymerization initiator was changed to 2,2-dimethoxy-2,2-diphenylethan-1-one having no absorption for light having a wavelength of 400 nm or more. In Comparative Example 2, the photopolymerization initiator was changed to 2-hydroxy-2-methyl-1-phenylpropan-1-one having no absorption for light having a wavelength of 400 nm or more.

(Evaluation 1)
A finger touch test was performed on the cured films obtained in Examples 1 to 9 and Comparative Examples 1 and 2, and the curability of the photocurable composition was evaluated. The results are shown in Table 1.

  From the results of Examples 1 to 3, the photocurable composition containing a photopolymerization initiator having an absorption for light having a wavelength of 400 nm or more has sufficient curability regardless of the presence or absence of a solvent. Do you get it. In addition, from the results of Examples 4 to 8, even when the amounts of the heteropolyacid compound, the polymerizable compound, and the photopolymerization initiator were changed, the photocuring including the photopolymerization initiator having an absorption for light having a wavelength of 400 nm or more was possible. The curable composition was found to have sufficient curability. Furthermore, from the results of Example 9, even when different types of heteropolyacid compounds are used, the photocurable composition containing a photopolymerization initiator having absorption for light having a wavelength of 400 nm or more has a sufficient curability. It was found to have

  On the other hand, the photocurable compositions of Comparative Examples 1 and 2 containing a photopolymerization initiator having no absorption for light having a wavelength of 400 nm or more retain their tackiness even after light irradiation, Did not progress sufficiently. This is presumably because the heteropolyacid compound blocked light having a wavelength component absorbed by the photopolymerization initiator, and the curing reaction did not proceed.

(Evaluation 2)
For the cured products obtained in Examples 1 and 4 to 8, the refractive index at a wavelength of 633 nm was measured using a reflection spectral thickness meter FE-3000 (manufactured by Otsuka Electronics Co., Ltd.). The results are shown in Table 2 and FIG. As described above, the “content of the heteropolyacid compound” shown in Table 2 and FIG. 1 is based on the weight of the photocurable composition excluding the solvent (d), as described above. It is the weight percentage where water was considered as the solvent.

  From Table 2 and FIG. 1, it can be seen that the refractive index of the cured product increases as the content of the heteropolyacid compound increases. Also, from FIG. 1, linearity is observed between the content of the heteropolyacid compound and the refractive index of the cured product. Furthermore, the range of the refractive index of the obtained cured product ranged from 1.570 to 1.782, which was higher than the range (approximately 1.4 to 1.6) that can be adjusted with a general-purpose acrylate resin. From these, it is understood that the cured product of the present invention has a large refractive index, and that the refractive index of the cured product of the present invention can be adjusted by the composition of the photocurable composition.

(About the effect of annealing treatment)
About the hardened | cured material obtained in Examples 1-9, it heats at 130 degreeC over 10 minutes, and after that, it leaves in 25 degreeC air and cools gradually, and the hardness of a hardened | cured material increases and the water resistance improves , And improved solvent resistance.

Claims (3)

(A) one or more heteropolyacid compounds;
(B) one or more polymerizable compounds;
(C) a photocurable composition comprising one or more photopolymerization initiators,
The heteropolyacid compound includes a heteropolyacid containing tungsten, an alkali metal salt of a heteropolyacid containing tungsten, an ammonium salt of a heteropolyacid containing tungsten, a heteropolyacid containing molybdenum, an alkali metal salt of a heteropolyacid containing molybdenum, and molybdenum. Selected from the group consisting of ammonium salts of heteropolyacids ,
The photopolymerization initiator has absorption for light having a wavelength of 400 nm or more,
The photocurable composition, wherein the content of the heteropolyacid compound (a) is 50 to 95% by mass based on the mass of the photocurable composition. (A) one or more heteropolyacid compounds;
(B) one or more polymerizable compounds;
A photocurable composition comprising (c) one or more photopolymerization initiators and (d) one or more solvents,
The heteropolyacid compound includes a heteropolyacid containing tungsten, an alkali metal salt of a heteropolyacid containing tungsten, an ammonium salt of a heteropolyacid containing tungsten, a heteropolyacid containing molybdenum, an alkali metal salt of a heteropolyacid containing molybdenum, and molybdenum. Selected from the group consisting of ammonium salts of heteropolyacids ,
The photopolymerization initiator has absorption for light having a wavelength of 400 nm or more,
The solvent has a boiling point under normal pressure of 250 ° C. or less,
The solvent is liquid at room temperature,
The photocurable composition, wherein the content of the heteropolyacid compound (a) is 50 to 95% by mass based on the mass of the photocurable composition excluding the component (d).   A cured product obtained by irradiating the photocurable composition according to claim 1 or 2 with light.