JP2006342254A - Method for producing photo-setting resin composition - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for producing an optical material having excellent optical properties to develop high diffraction efficiency over a wide wavelength range while keeping practically sufficient scattering property and shape-retention. <P>SOLUTION: The photo-setting resin composition contains a polyfunctional monomer having at least two functional groups having unsaturated double bond, a monofunctional monomer having one functional group having unsaturated double bond, a photopolymerization initiator and indium-tin oxide fine particles. An optical material having excellent optical properties to develop high diffraction efficiency over a wide wavelength range while keeping practically sufficient scattering property and shape-retention can be produced by using the resin composition. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a method for producing an optical material used for optical elements such as a refractive optical element and a diffractive optical element. In particular, the present invention relates to a method for producing a photocurable resin composition having an excellent refractive index wavelength dispersibility and secondary dispersibility.

  2. Description of the Related Art Conventionally, in a refractive optical system configured only by light refraction, chromatic aberration is reduced by combining glass materials having different refractive index wavelength dispersion characteristics. However, this may make it very difficult to sufficiently correct chromatic aberration when the configuration and number of lenses are limited or when the glass material used is limited.

  On the other hand, SPIE Vol. 1354 International Lens Design Conference (1990) discloses a method of reducing chromatic aberration by using a diffractive optical element having a diffraction grating on a lens surface or a part of an optical system. This utilizes the physical phenomenon that the direction in which chromatic aberration occurs with respect to a light beam having a certain reference wavelength is reversed between the refracting surface and the diffractive surface as an optical element. Furthermore, such a diffractive optical element can have the same effect as an aspherical lens by changing the period of the periodic structure of the diffraction grating. Therefore, it has a very great effect on the reduction of chromatic aberration.

  However, in the diffractive optical element, since one incident light beam is divided into a plurality of lights of each order due to the diffraction action, in order to fully exhibit the features of the diffractive optical element, a light beam in a used wavelength region is changed to a specific order ( (Hereinafter referred to as the design order). When the luminous flux in the operating wavelength range is concentrated in the design order, the diffracted light intensity of the other diffraction orders becomes very low, so that the light other than the design order is different from the light of the design order. There is no flare light that forms an image.

  In order to concentrate the luminous flux in the used wavelength region to the design order, it is necessary to optimally design the grating structure of the diffraction grating and the optical characteristics of the material used for the element. In JP-A-2004-78166 (Patent Document 1) and JP-A-2004-145273 (Patent Document 2), an optical system is composed of a combination of a plurality of diffractive optical elements, and is formed on a boundary surface of each optical element. A diffractive optical element having high diffraction efficiency in a wide wavelength range is disclosed by optimally designing the shape of the grating and the wavelength dispersion and second-order dispersion of the refractive index of the material used for each optical element.

Focusing on the optical material used, in order to obtain a diffractive optical element having a high diffraction efficiency in a wide wavelength range, the refractive index and its wavelength dispersion (ν _d ), and its secondary dispersion (θ _{g, F} ) By focusing on and optimizing, it has achieved high diffraction efficiency in a wide wavelength range. As an optical material that realizes the optimal optical characteristics, indium tin oxide (hereinafter referred to as ITO) in a binder (organic material) An optical material containing inorganic fine particles such as fine particles is disclosed.
Japanese Patent Laid-Open No. 2004-78166 JP 2004-145273 A

  However, the optical material described above has excellent optical characteristics that exhibit high diffraction efficiency in a wide wavelength range, but there is a detailed description of the scattering rate, which is an important characteristic as an optical material used in an imaging optical system. Not enough. In the imaging optical system, scattered light causes flare and reduces contrast.

  In the case of an optical material in which inorganic fine particles having different refractive indexes are dispersed in an organic material, the scattering characteristics vary greatly depending on the dispersion state of the fine particles. In order to suppress light scattering in the visible light region, it is necessary to control the particle size of the inorganic fine particles to 100 nm or less, and therefore, it is necessary to uniformly disperse the inorganic fine particles without aggregating them. The dispersion state varies greatly depending on the binder (organic material) used as the matrix, the inorganic fine particles, and the molecular structure and surface state of the dispersion solvent and dispersant. It is greatly influenced by the method.

  Furthermore, the dispersion solvent used to uniformly disperse the inorganic fine particles improves the dispersibility and facilitates compatibility with the resin. However, if it remains in the optical element molded body, It becomes a factor causing a change in optical characteristics and volume shrinkage. In order to exhibit high diffraction efficiency, in addition to the optical characteristics and scattering characteristics of the optical material used, characteristics that accurately hold the grating in a desired shape are also important. It is necessary to remove the dispersion solvent to a sufficient extent.

  In order to solve the above problems, the present invention provides a method for producing an optical material having practically sufficient scattering characteristics and shape retention characteristics while having excellent optical characteristics exhibiting high diffraction efficiency in a wide wavelength range. The purpose is to do.

  The present invention provides methods for producing optical materials shown in the following (1) to (5).

  (1) A polyfunctional monomer having at least two functional groups having an unsaturated double bond, a monofunctional monomer having one functional group having an unsaturated double bond, a photopolymerization initiator, and indium tin oxide fine particles A method for producing a photocurable resin composition, comprising:

  (2) an oligomer component having at least two functional groups having an unsaturated double bond, a polyfunctional monomer having at least two functional groups having an unsaturated double bond, and a functional group having an unsaturated double bond A method for producing a photocurable resin composition, comprising a monofunctional monomer having one of the above, a photopolymerization initiator, and indium tin oxide fine particles.

  (3) The method for producing a photocurable resin composition according to (2), wherein the oligomer component has a number average molecular weight of 1,000 to 5,000.

  (4) The method for producing a photocurable resin composition according to (2) to (3), wherein the weight ratio of the oligomer component in the photocurable resin composition is 30% by weight or less in the organic component .

  (5) The method for producing a photocurable resin composition according to (1) to (4), wherein the particle diameter of the indium tin oxide fine particles is 1 to 100 nm.

  The binder is not particularly limited as long as it satisfies desired optical characteristics, scattering characteristics, shape characteristics, and moldability, but a photocurable resin composition that is cured by light, particularly ultraviolet rays, is used at the time of molding. Compared to a thermoplastic resin composition and a thermosetting resin composition that need to be heat-treated, it is more preferable because the optical properties of the resin are reduced due to thermal history during molding and the dimensional change due to thermal shrinkage is small.

  The polyfunctional monomer having at least two functional groups having an unsaturated double bond is a compound having two or more (meth) acrylate groups, vinyl groups, etc. in the molecule as unsaturated double bonds, For example, ethylene glycol di (meth) acrylate, diethylene glycol di (meth) acrylate, triethylene glycol di (meth) acrylate, tetraethylene glycol di (meth) acrylate, dipropylene glycol di (meth) acrylate, tripropylene glycol di (meth) ) Acrylate, triglycerol di (meth) acrylate, neopentyl glycol di (meth) acrylate, hydroxypivalic acid neopentyl glycol di (meth) acrylate, bis ((meth) acryloxyethyl) hydroxyethyl isocyanur 1,3-butylene glycol di (meth) acrylate, 1,4-butanediol di (meth) acrylate, 1,6-hexanediol di (meth) acrylate, tricyclodecane dimethanol (meth) acrylate, penta Erythritol tri (meth) acrylate, trimethylolpropane tri (meth) acrylate, trimethylolpropane benzoate (meth) acrylate, tris ((meth) acryloxyethyl) isocyanurate, ditrimethylolpropane tetra (meth) acrylate, pentaerythritol tetra ( (Meth) acrylate, dipentaerythritol hydroxypenta (meth) acrylate, dipentaerythritol hexa (meth) acrylate, divinyl adipate, diallyl phthalate, triallyl isocyanurate It can be used alone or in combination of two or more.

  When the polyfunctional monomer is cast and photocured on a mold having a desired diffractive surface and a refracting surface, the polyfunctional monomer suppresses the shape change of the resin composition molded body of the present invention over time, and the surface. Increase hardness. In particular, when the resin composition molded article of the present invention is used as a diffractive optical element, the height of the diffraction grating and the shape of the diffractive surface are important elements for the expression of high diffraction efficiency. For this reason, the resin composition molded body of the present invention has an accurate shape with respect to a desired design value, and it is necessary to accurately maintain the shape regardless of changes with time, particularly temperature and humidity. Specifically, the height of the diffraction grating must be maintained within an error range of about ± 0.5% with respect to a desired design value.

  As a result of intensive studies by the inventor, the above-mentioned polyfunctional monomer is used in the resin composition, and the content thereof is 20 to 70 wt%, further 30 to 60 wt% in the organic component of the photocurable resin composition of the present invention. As a result, it was found that the shape change of the molded body over time can be suppressed.

  The monofunctional monomer having one functional group having an unsaturated double bond is a compound having one (meth) acrylate group, vinyl group or the like as an unsaturated double bond in the molecule. For example, methyl (Meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, isopropyl (meth) acrylate, butyl (meth) acrylate, isobutyl (meth) acrylate, tertiary butyl (meth) acrylate, pentyl (meth) acrylate, hexyl (Meth) acrylate, 2-ethylhexyl (meth) acrylate, octyl (meth) acrylate, isooctyl (meth) acrylate, isodecyl (meth) acrylate, lauryl (meth) acrylate, isomyristyl (meth) acrylate, stearyl (meth) acrylic , Isostearyl (meth) acrylate, 2-hydroxyethyl (meth) acrylate, hydroxypropyl (meth) acrylate, 2-hydroxybutyl (meth) acrylate, 2-methoxyethyl (meth) acrylate, 3-methoxybutyl (meta ) Acrylate, butoxyethyl (meth) acrylate, butanediol mono (meth) acrylate, dipropylene glycol (meth) acrylate, methoxytriethylene glycol (meth) acrylate, methoxydipropylene glycol (meth) acrylate, methoxytripropylene glycol (meth) ) Acrylate, ethyl carbitol (meth) acrylate, 2-ethylhexyl carbitol (meth) acrylate, cyclohexyl (meth) acrylate, tertiary butyl cyclohexane Sil (meth) acrylate, isobornyl (meth) acrylate, dicyclopentanyl (meth) acrylate, dicyclopentenyl (meth) acrylate, dicyclopentenyloxyethyl (meth) acrylate, 2- (meth) acryloyloxyethyl hexahydro Phthalate, tetrahydrofurfuryl (meth) acrylate, (meth) acryloylmorpholine, dimethylaminoethyldicyclopentanyl (meth) acrylate, phenyl (meth) acrylate, phenoxyethyl (meth) acrylate, phenoxydiethylene glycol (meth) acrylate, phenoxy Tetraethylene glycol (meth) acrylate, phenoxyhexaethylene glycol (meth) acrylate, benzyl (meth) acrylate, 2- (meth) acrylo Roxyethyl phthalate, 2- (meth) acryloyloxyethyl-2-hydroxyethyl phthalate, 2- (meth) acryloyloxypropyl phthalate, neopentyl glycol benzoate (meth) acrylate, α-naphthyl (meth) acrylate, β- Naphthyl (meth) acrylate, imide acrylate, trifluoroethyl (meth) acrylate, tetrafluoropropyl (meth) acrylate, octafluoropentyl (meth) acrylate, perfluorooctylethyl (meth) acrylate, vinylpyrrolidone, N-vinylcaprolactam, One or more of 1-vinylimidazole, vinylnaphthalene, vinylcarbazole, N-vinylphthalimide and the like can be used.

The monofunctional monomer adjusts the refractive index at each wavelength of the resin composition of the present invention and has an appropriate viscosity. In the resin composition of the present invention, the refractive index, its wavelength dispersion (ν _d ), and its secondary dispersion (θ _{g, F} ) can be set to values that cannot be obtained with organic substances by introducing ITO fine particles. However, when it is necessary to further adjust the refractive index, chromatic dispersion (ν _d ), and secondary dispersion (θ _{g, F} ), the desired refractive index, chromatic dispersion (ν _d ), A secondary dispersion (θ _{g, F} ) is obtained.

  In general, when the amount of fine particles added to a resin increases, the resin viscosity tends to increase. An increase in viscosity reduces moldability, particularly developability when casting a resin on a mold. The viscosity required to ensure sufficient developability depends on the shape of the mold and the molding conditions such as the mold shape and the thickness of the molded body, but is generally about 50,000 mPa · s or less. Is desired.

As a result of intensive studies by the present inventors, the above-mentioned monofunctional monomer was used in the resin composition, and the content thereof was 15 to 65 wt%, more preferably 25 to 55 wt% in the organic component of the photocurable resin composition of the present invention. It was found that the desired refractive index, wavelength dispersion (ν _d ), secondary dispersion (θ _{g, F} ), and resin viscosity can be obtained.

  Examples of the photopolymerization initiator include one or two selected from benzyl dimethyl ketals, α-hydroxy ketones, amino ketones, acetophenone and derivatives thereof, benzophenone and derivatives thereof, benzoin and derivatives thereof, oxime compounds, and the like. The above can be used. Of these, 2,2-dimethoxy-1,2-diphenylethane-1-one, 1-hydroxycyclohexyl phenyl ketone and the like are particularly preferable.

The ITO fine particles can impart a refractive index and its wavelength dispersion (ν _d ) that cannot be obtained with an organic substance, and further its secondary dispersion (θ _{g, F} ). However, since it is necessary to practically sufficiently reduce light scattering due to addition of ITO fine particles, the particle diameter is more preferably 1 to 100 nm.

  As the oligomer, one or more selected from acrylic, (unsaturated) polyester, epoxy, urethane acrylate compounds and the like can be used.

  The oligomer imparts low shrinkage when effective to the photocurable resin composition of the present invention, and makes the photocurable resin composition molded body of the present invention tough. The number average molecular weight of the oligomer is preferably 1000 to 5000, and if the number average molecular weight is less than 1000, the amount of shrinkage at the time of curing is large and the shape accuracy of the molded article is lowered. On the other hand, if it is larger than 5000, the viscosity of the photocurable resin composition of the present invention is remarkably increased, and it becomes difficult to cast the photocurable resin composition of the present invention into a mold. Similarly, when the weight ratio of the oligomer component in the photocurable resin composition of the present invention is 30% by weight or more in the organic component, the moldability deteriorates due to a significant increase in viscosity.

  A known polymerization accelerator, polymerization inhibitor, dispersant, antifoaming agent, leveling agent, release agent and the like can be added to the photocurable resin composition of the present invention as necessary.

  The method for producing a photocurable resin composition of the present invention comprises a dissolution step of dissolving a binder resin in an ITO dispersion composed of ITO fine particles, a dispersion solvent, and a dispersant, and then a solvent removal step of removing the dispersion solvent.

  When the binder resin is dissolved in the dispersion, it is necessary to slowly add and dissolve the desired amount of the binder resin while stirring the dispersion obtained in advance. When stirring is not performed or when a large amount of binder resin is added at once, there is a possibility that a large concentration unevenness occurs in the dispersion and the fine particles in the dispersion are aggregated.

  Removal of the dispersion solvent is performed by heating under reduced pressure. At this time, in order to suppress aggregation of fine particles, volatilization of the binder component, high molecular weight of the binder component and thermal decomposition, the processing temperature, processing pressure, processing It is necessary to control the time accurately.

  More specifically, the treatment temperature depends on the type of solvent to be removed, but it is necessary to set the temperature to 90 ° C. or lower, more preferably 60 ° C. or lower in order to suppress thermal polymerization or thermal decomposition of the binder. Since it is necessary to control the processing pressure while paying attention to the volatilization of the binder component and bumping of the residual solvent, it is necessary to gradually decrease the pressure from atmospheric pressure to 1 hPa, more preferably from atmospheric pressure to 2 hPa. The treatment time depends on the amount treated and the amount of solvent that can remain. As a result of intensive studies by the present inventors, the amount of solvent that can be retained can be determined from the shape retention characteristics after molding, and the height of the diffraction grating, which is one index of shape retention, is below the desired design value. It must be maintained within an error range of about ± 0.5%. Therefore, the amount of solvent that can remain is required to be 0.3 wt% or less, more preferably 0.2 wt% or less in the photocurable resin composition of the present invention. Therefore, it is effective to determine the treatment time while confirming the amount of residual solvent by appropriately measuring the change in weight.

  ADVANTAGE OF THE INVENTION According to this invention, the manufacturing method of the optical material which has a scattering characteristic and shape retention characteristic sufficient practically can be provided, having the outstanding optical characteristic which expresses high diffraction efficiency in a wide wavelength range.

  Hereinafter, examples of the present invention will be described in detail.

  While stirring 375.14 g of a toluene solution in which 5% by weight of ITO fine particles having an average particle diameter of 10 nm containing a dispersant of 20% by weight with respect to the weight of ITO was stirred with a magnetic stirrer, 10.99 g of pentaerythritol tetraacrylate, 15.12 of cyclohexyl acrylate g, 1.37 g of resin mixture of 2,2-dimethoxy-1,2-diphenylethane-1-one was gradually added over about 15 minutes, and then stirred for about 15 minutes to completely dissolve in the toluene solution. . Thereafter, toluene was distilled off while reducing the pressure from atmospheric pressure to 2 hPs in 48 hours using a rotary evaporator. The water bath temperature at that time was 50 ° C., and the distilled toluene was appropriately removed from the system. The residual solvent amount and the light scattering rate of the photocurable resin composition obtained by the above operation were measured by the following methods. The results are shown in Table 1.

  While stirring 488.10 g of a methyl isobutyl ketone solution in which 5 wt% of ITO fine particles having an average particle diameter of 30 nm containing a dispersant of 20 wt% with respect to the ITO weight were dispersed by a magnetic stirrer, 3.11 g of ethylene glycol dimethacrylate, A resin mixture of 9.32 g of methylolpropane triacrylate, 7.25 g of dicyclopentanyl acrylate, and 1.04 g of 1-hydroxycyclohexyl phenyl ketone is gradually added over about 15 minutes, and then stirred for about 15 minutes in the methyl isobutyl ketone solution. It was completely dissolved. Thereafter, methyl isobutyl ketone was distilled off while reducing the pressure from atmospheric pressure to 2 hPs in 64 hours using a rotary evaporator. The water bath temperature at that time was 60 ° C., and the distilled off methyl isobutyl ketone was appropriately removed from the system. The residual solvent amount and the light scattering rate of the photocurable resin composition obtained by the above operation were measured by the following methods. The results are shown in Table 1.

  Nippon Kayaku Co., Ltd. with a number average molecular weight of about 3,000, while stirring with a magnetic stirrer 25.88g of a toluene solution in which 10% by weight of ITO fine particles with an average particle size of 80nm containing a dispersant of 15% by weight of ITO was dispersed. Company urethane acrylate Kayrad (registered trademark) UX-4101 9.40 g, neopentyl glycol dimethacrylate 7.05 g, dipentaerythritol hexaacrylate 7.05 g, isobutyl methacrylate 21.16 g, 1-hydroxycyclohexyl phenyl ketone 2.35 g The mixture was gradually added over a period of minutes, and then the stirring was continued for about 25 minutes until it was completely dissolved in the toluene solution. Thereafter, toluene was distilled off while reducing the pressure from atmospheric pressure to 2 hPs in 32 hours using a rotary evaporator. The water bath temperature at that time was 50 ° C., and the distilled toluene was appropriately removed from the system. The residual solvent amount and the light scattering rate of the photocurable resin composition obtained by the above operation were measured by the following methods. The results are shown in Table 1.

  Hitachi Chemical Co., Ltd. with a number average molecular weight of about 1,000 while stirring 244.05 g of xylene solution containing 10% by weight of ITO fine particles with an average particle diameter of 10 nm containing a dispersant of 15% by weight with respect to the ITO weight with a magnetic stirrer Company made polyester acrylate Hitaloid (registered trademark) 7841 3.29 g, tris (2-acryloxyethyl) isocyanurate 4.39 g, pentaerythritol triacrylate 5.48 g, dicyclopentenyloxyethyl methacrylate 7.68 g, 1-hydroxycyclohexyl phenyl ketone 1.10 g The resin mixture was gradually added over about 15 minutes and then stirred for about 15 minutes to completely dissolve in the xylene solution. Thereafter, xylene was distilled off while reducing the pressure from atmospheric pressure to 2 hPs in 72 hours using a rotary evaporator. The water bath temperature at that time was 50 ° C., and the distilled xylene was appropriately removed from the system. The residual solvent amount and the light scattering rate of the photocurable resin composition obtained by the above operation were measured by the following methods. The results are shown in Table 1.

  While stirring 187.57 g of a toluene solution in which 10% by weight of ITO fine particles having an average particle diameter of 30 nm containing a dispersant of 15% by weight with respect to the weight of ITO was stirred with a magnetic stirrer, 11.37 g of pentaerythritol tetraacrylate, N-vinyl A resin mixture of 4.26 g caprolactam, 11.37 g isobornyl methacrylate, and 1.42 g 2,2-dimethoxy-1,2-diphenylethane-1-one was gradually added over about 15 minutes, and then the stirring was continued for about 15 minutes. It was completely dissolved in the toluene solution. Thereafter, toluene was distilled off while reducing the pressure from atmospheric pressure to 2 hPs in 28 hours using a rotary evaporator. The water bath temperature at that time was 50 ° C., and the distilled toluene was appropriately removed from the system. The residual solvent amount and the light scattering rate of the photocurable resin composition obtained by the above operation were measured by the following methods. The results are shown in Table 1.

(Comparative Example 1)
Pentaerythritol tetraacrylate 10.99g, cyclohexyl acrylate 15.12g, 2,2 in 375.14g of toluene solution in which 5% by weight of ITO fine particles with an average particle diameter of 10nm containing 20% by weight of dispersant is contained with respect to the weight of ITO. -Dimethoxy-1,2-diphenylethane-1-one 1.37 g of resin mixture was added in one portion. Thereafter, toluene was distilled off while reducing the pressure from atmospheric pressure to 2 hPs in 48 hours using a rotary evaporator. The water bath temperature at that time was 50 ° C., and the distilled toluene was appropriately removed from the system. The residual solvent amount and the light scattering rate of the photocurable resin composition obtained by the above operation were measured by the following methods. The results are shown in Table 1.

(Comparative Example 2)
While stirring 375.14 g of a toluene solution in which 5% by weight of ITO fine particles having an average particle diameter of 10 nm containing a dispersant of 20% by weight with respect to the weight of ITO was stirred with a magnetic stirrer, 10.99 g of pentaerythritol tetraacrylate, 15.12 of cyclohexyl acrylate g, 1.37 g of resin mixture of 2,2-dimethoxy-1,2-diphenylethane-1-one was gradually added over about 15 minutes, and then stirred for about 15 minutes to completely dissolve in the toluene solution. . Thereafter, toluene was distilled off while reducing the pressure from atmospheric pressure to 2 hPs in 6 hours using a rotary evaporator. The water bath temperature at that time was 50 ° C., and the distilled toluene was appropriately removed from the system. The residual solvent amount and the light scattering rate of the photocurable resin composition obtained by the above operation were measured by the following methods. The results are shown in Table 1.

(Comparative Example 3)
While stirring 375.14 g of a toluene solution in which 5% by weight of ITO fine particles having an average particle diameter of 10 nm containing a dispersant of 20% by weight with respect to the weight of ITO was stirred with a magnetic stirrer, 10.99 g of pentaerythritol tetraacrylate, 15.12 of cyclohexyl acrylate g, 1.37 g of resin mixture of 2,2-dimethoxy-1,2-diphenylethane-1-one was gradually added over about 15 minutes, and then stirred for about 15 minutes to completely dissolve in the toluene solution. . Thereafter, toluene was distilled off while reducing the pressure from atmospheric pressure to 2 hPs in 48 hours using a rotary evaporator. The water bath temperature at that time was gradually raised from 50 ° C. to 110 ° C., and the distilled toluene was appropriately removed from the system. The photocurable resin composition obtained by the above operation became a gel.

(Measurement of residual solvent amount)
The amount of residual solvent was calculated from the weight of the obtained photocurable resin composition and the weight obtained by removing the weight of the dispersion solvent from the charged weight of each component of the photocurable resin composition.

(Measurement of scattering rate)
The resulting photocurable resin composition was developed so that the thickness was about 10 μm between two sheets of OHRA glass S-BSL7 facing each other in parallel, and a spot UV light source manufactured by HOYA CANDEO OPTRONICS Co., Ltd. After photocuring using an apparatus EXECURE (registered trademark) 3000 at an irradiation amount of 3,000 mJ / cm ² , one glass substrate was peeled off to obtain a sample for scattering rate measurement. The scattering rate of the obtained sample was measured by making light incident from the cured resin side using a spectrophotometer U-4000 manufactured by Hitachi High-Technologies Corporation equipped with an integrating sphere.

  Table 1 shows the evaluation results of the residual solvent amount and scattering rate of the photocurable resin composition obtained in each example and comparative example.

  Although the residual solvent amount showed a good value in Examples 1 to 5 and Comparative Example 1, Comparative Example 2 had a residual solvent amount of 0.3 wt% or more because the removal time of the dispersed solvent was short.

  The scattering rate is difficult to evaluate because the required characteristics vary depending on the optical system used and its element thickness, but it is generally desirable that the scattering rate be 1% or less at a film thickness of 10 μm. In Examples 1 to 5, the scattering rate showed a good value of 1% or less, but in Comparative Example 1, the scattering rate exceeded 1% due to the aggregation of fine particles when the resin component was added. I think that the. In Comparative Example 2, the dispersion solvent removal process was performed in a short time, so the dispersion solvent was rapidly removed and the fine particles were aggregated. Thus, it is considered that the scattering rate exceeded 1%.

  In Comparative Example 3, since the photocurable resin composition became a gel, it was determined to be unsuitable for practical use.

Claims (5)

  A polyfunctional monomer having at least two functional groups having an unsaturated double bond; a monofunctional monomer having one functional group having an unsaturated double bond; a photopolymerization initiator; and indium tin oxide fine particles. The manufacturing method of the photocurable resin composition characterized by these.   One oligomer component having at least two functional groups having an unsaturated double bond, one polyfunctional monomer having at least two functional groups having an unsaturated double bond, and one functional group having an unsaturated double bond The manufacturing method of the photocurable resin composition characterized by including the monofunctional monomer which has, a photoinitiator, and an indium tin oxide microparticle.   The method for producing a photocurable resin composition according to claim 2, wherein the oligomer component has a number average molecular weight of 1,000 to 5,000.   4. The method for producing a photocurable resin composition according to claim 2, wherein the weight ratio of the oligomer component in the photocurable resin composition is 30% by weight or less in the organic component.   5. The method for producing a photocurable resin composition according to claim 1, wherein the particle diameter of the indium tin oxide fine particles is 1 to 100 nm.