Photocurable resin composition, optical molded product, optical device, and method for producing optical molded product

Abstract

Provided is a photocurable resin composition that can be used in an optical molded body, wherein the photocurable resin composition has an absorbance of 0.300 or less at a wavelength of 405 nm as measured according to a specific method.

Description

Photocurable resin composition, optical molded body, optical device, and method for manufacturing optical molded body

[0001] The present invention relates to a photocurable resin composition, an optical molded body, an optical device, and a method for producing an optical molded body.

[0002] In recent years, thermoplastic resins and ultraviolet-curable resin compositions have been studied in the field of optical lenses from the viewpoints of heat resistance and low birefringence. Among these, methacrylic resin compositions, which are thermoplastic resins, have been studied. For example, techniques for methacrylic resin compositions are described in Patent Documents 1 and 2.

[0003] Patent Document 1 describes an object of providing a methacrylic resin composition that has high heat resistance, highly controlled birefringence, high light transmittance over a long optical path, and excellent color tone and transparency. The composition contains a methacrylic resin that contains at least a structural unit derived from an N-substituted maleimide monomer in the main chain, and has a glass transition temperature of more than 120°C and 160°C or less, and a shear rate of 1000 sec at a resin temperature of 270°C. ―１ The melt viscosity under the condition of is 250 Pa sec or less, and the absolute value of the photoelastic coefficient is 1×10 ―１２ pa ―１ The document describes a methacrylic resin composition, which has a light transmittance of 94% or more when measured under conditions of an optical path length of 100 mm and a wavelength of 470 nm, and a light transmittance of 96% or more when measured under conditions of a wavelength of 700 nm, when the resin composition is dissolved in chloroform at a mass to volume ratio of 20%.

[0004] Patent Document 2 describes a photocurable composition that is fast-curing, non-anaerobic, low-viscosity, low-odor, and has excellent storage stability, and in particular, that provides a cured product that is excellent in various properties required for lenses, such as colorless transparency, low optical distortion, heat resistance, low water absorption, toughness, and high hardness. The photocurable composition contains a tricyclodecane-skeleton di(meth)acrylate (A), a trifunctional or tetrafunctional secondary thiol (B), a cleavage-type photopolymerization initiator (C), and a hindered phenol-based antioxidant (D), and is characterized in that the photocurable composition does not contain a primary thiol, and the content ratio (weight ratio) of components (A), (B), (C), and (D) is within the following range: Component (A) / Component (B) = 75 / 25 to 95 / 5 Component (C): 2 to 10 parts by weight per 100 parts by weight of the total of Components (A) and (B) Component (D): 0.1 to 1 part by weight per 100 parts by weight of the total of Components (A) and (B)

[0005] JP 2019-35015 A JP 2022-32186 A

[0006] The present invention provides a photocurable resin composition that can reduce surface unevenness of an optical molded product.

[0007] The present inventors conducted extensive research to achieve the above-mentioned object. As a result, they found that the absorbance at 405 nm of a photocurable resin composition measured under specific conditions is correlated with the surface unevenness of the resulting optical molded body. Based on the above findings, the present inventors conducted further extensive research and found that the surface unevenness of the optical molded body can be reduced by using a photocurable resin composition having an absorbance at 405 nm of 0.300 or less measured under specific conditions, thereby completing the present invention.

[0008] [1] A photocurable resin composition that can be used for an optical molded body, wherein the photocurable resin composition has an absorbance A at a wavelength of 405 nm measured according to the following <Measurement method>. ４０５A sample was prepared by dissolving the photocurable resin composition in isopropanol at a mass ratio of 7:93. The sample was then placed in a sample cell with an optical path length of 10 mm, and the incident light intensity I ０ When light having a wavelength of 405 nm is incident on the sample cell, the transmitted light intensity I of the light transmitted through the sample cell is measured, and the absorbance A at a wavelength of 405 nm is calculated by the following formula (1). ４０５ Calculate (1): A ４０５ = -log １０ (I / I ０ [2] The absorbance A ４０５The photocurable resin composition according to [1] above, wherein the (meth)acrylate monomer is 0.010 or more. [3] The photocurable resin composition according to [1] or [2] above, which contains a (meth)acrylate monomer. [4] The photocurable resin composition according to [3] above, wherein the (meth)acrylate monomer contains one or more selected from the group consisting of monofunctional (meth)acrylate monomers and di- or higher functional (meth)acrylate monomers. [5] The photocurable resin composition according to [3] or [4] above, wherein the (meth)acrylate monomer contains a (meth)acrylate monomer having an alicyclic skeleton. [6] The photocurable resin composition according to [5] above, wherein the (meth)acrylate monomer having an alicyclic skeleton contains one or more skeletons selected from the group consisting of an adamantane skeleton, a norbornane skeleton, and a dicyclopentadiene skeleton. [7] The photocurable resin composition according to [5] or [6], wherein the content of the (meth)acrylate monomer having an alicyclic skeleton is 30 parts by mass or more and 100 parts by mass or less, when the total content of the (meth)acrylate monomers is 100 parts by mass. [8] The photocurable resin composition according to any one of [3] to [7], wherein the (meth)acrylate monomer comprises a (meth)acrylate monomer having a linear hydrocarbon skeleton. [9] The photocurable resin composition according to any one of [1] to [8], further comprising a photopolymerization initiator.

[10] The photocurable resin composition according to [9], wherein the photopolymerization initiator comprises a photoradical polymerization initiator.

[11] The photocurable resin composition according to [9] or

[10] , wherein the content of the photopolymerization initiator is 0.10 parts by mass or more and 10 parts by mass or less, when the total content of the (meth)acrylate monomers is 100 parts by mass.

[12] The photocurable resin composition according to any one of [1] to

[11] above, further comprising an antioxidant.

[13] The photocurable resin composition according to

[12] above, wherein the content of the antioxidant is 0.010 parts by mass or more and 10 parts by mass or less, when the total content of the (meth)acrylate monomers is 100 parts by mass.

[14] The photocurable resin composition according to any one of [1] to

[13] above, further comprising a light stabilizer.

[15] The photocurable resin composition according to

[14] , wherein the content of the light stabilizer is 0.010 parts by mass or more and 5 parts by mass or less, when the total content of the (meth)acrylate monomers is 100 parts by mass.

[16] The photocurable resin composition according to any one of [1] to

[15] , wherein the content of the (meth)acrylate monomers is 80% by mass or more and less than 100% by mass, when the total content of the photocurable resin composition is 100% by mass.

[17] The photocurable resin composition according to any one of [1] to

[16] , which is usable in a casting method.

[18] An optical molded body comprising a cured product of the photocurable resin composition according to any one of [1] to

[17] .

[19] The optical molded body according to

[18] , wherein the optical molded body comprises a lens.

[20] The optical molded body according to

[19] , wherein the lens comprises one or more lenses selected from a lens for a virtual reality device (VR lens), a lens for a mixed reality device (MR lens), a lens for an augmented reality device (AR lens), a lens for a cross reality device (xR lens), and a lens for a head-mounted display (HMD lens).

[21] The optical molded body according to any one of

[18] to

[20] , wherein the maximum thickness portion is 20.0 mm or less.

[22] The optical molded body according to any one of

[18] to

[21] , wherein the maximum thickness portion of the optical molded body is 1.0 mm or more.

[23] An optical device comprising the optical molded body according to any one of

[18] to

[22] .

[24] A method for producing an optical molded body, comprising: a thickening step of increasing the viscosity of a photocurable resin composition by irradiating the photocurable resin composition with light using an irradiation device having a light source peak at a wavelength of 360 nm or more and 410 nm or less, and a curing step of curing the photocurable resin composition by irradiating the photocurable resin composition with light using an irradiation device having a light source peak at a wavelength of 360 nm or more and 410 nm or less, after the thickening step.

[25] The method for producing an optical molded body according to

[24] , further comprising: a step of placing an upper mold for molding on the photocurable resin composition after the thickening step and before the curing step.

[26] The method for producing an optical molded body according to

[24] or

[25] , further comprising a coating step of coating the photocurable resin composition on a lower mold for molding, wherein the thickening step is performed after the coating step.

[27] The method for producing an optical molded body according to any of

[24] to

[26] , wherein the thickening step comprises a step of irradiating the photocurable resin composition with light at an irradiation intensity of 90 mW to 130 mW using an irradiation device having a light source peak in a wavelength range of 360 nm to 410 nm.

[28] The method for producing an optical molded body according to any of

[24] to

[27] , wherein the thickening step comprises a step of irradiating the photocurable resin composition with light for an irradiation time of 1 second to 300 seconds using an irradiation device having a light source peak in a wavelength range of 360 nm to 410 nm.

[29] The method for producing an optical molded body according to any one of

[24] to

[28] , wherein the thickening step includes a step of irradiating the photocurable resin composition with light at an integrated light quantity of 50 mJ or more and 20.0 J or less using an irradiation device having a light source peak at a wavelength of 360 nm or more and 410 nm or less.

[30] The method for producing an optical molded body according to any one of

[24] to

[29] , wherein in the thickening step, the photocurable resin composition has a thickness of 15.0 mm or less.

[31] The method for producing an optical molded body according to any one of

[24] to

[30] , wherein the photocurable resin composition comprises the photocurable resin composition according to any one of [1] to

[17] .

[0009] According to the present invention, a photocurable resin composition capable of reducing surface unevenness of an optical molded body can be provided.

[0010] In this specification, the term "(meth)acrylate" represents a concept that encompasses both acrylate and methacrylate. The same applies to similar terms such as "(meth)acryloyl." For each component of this embodiment, one type may be used, or two or more types may be used in combination. Furthermore, the term "to" representing a numerical range means "greater than or equal to" or "less than or equal to," and includes both the upper and lower limits.

[0011] (Photocurable Resin Composition) The photocurable resin composition of this embodiment (hereinafter also referred to simply as "resin composition") is a photocurable resin composition that can be used for an optical molded body. The photocurable resin composition of this embodiment has an absorbance A at a wavelength of 405 nm measured according to the following <Measurement Method>. ４０５ The photocurable resin composition is dissolved in isopropanol at a mass ratio of 7:93 to prepare a sample. The sample is then placed in a sample cell with an optical path length of 10 mm, and the incident light intensity I is measured at a wavelength of 405 nm. ０ When light having a wavelength of 405 nm is incident on the sample cell, the transmitted light intensity I of the light transmitted through the sample cell is measured. The absorbance A at a wavelength of 405 nm is calculated by the following equation (2). ４０５ (2): A ４０５ = -log １０ (I / I ０ The photocurable resin composition of this embodiment has the above-described structure, and thus can reduce surface unevenness of the optical molded body.

[0012] The photocurable resin composition contains, for example, a polymerizable compound. The polymerizable compound preferably contains a (meth)acrylate monomer (A) from the viewpoint of further reducing surface unevenness of the optical molded body.

[0013] The properties of the photocurable resin composition are not particularly limited. However, from the viewpoint of suitability for forming an optical molded body by molding using an injection method or molding using a cast method, the photocurable resin composition is preferably in a liquid state. Furthermore, from the viewpoint of improving the degree of freedom in designing the optical molded body, the photocurable resin composition is preferably used for molding using a cast method.

[0014] Next, the components of the photocurable resin composition will be described with specific examples. The photocurable resin composition may be composed of a polymerizable compound, or may contain components other than the polymerizable compound. Specific examples of other components of the photocurable resin composition may include one or more selected from the group consisting of an antioxidant (B), a photopolymerization initiator (C), and a light stabilizer (D), which will be described later.

[0015] <Polymerizable Compound> The polymerizable compound may be any compound having a polymerizable functional group, and is preferably a compound having a radically polymerizable functional group. From the viewpoint of further reducing the surface unevenness of the optical molded body, the radically polymerizable functional group may be, for example, a (meth)acryloyl group. From the viewpoint of further reducing the surface unevenness of the optical molded body, the polymerizable compound preferably contains a (meth)acrylate monomer (A).

[0016] <(Meth)acrylate Monomer (A)> The (meth)acrylate monomer (A) is a compound having a (meth)acryloyl group. The (meth)acrylate monomer (A) is a molecule that can bond to other molecules by radical polymerization of the (meth)acryloyl group.

[0017] From the viewpoint of improving the strength of an optical molded body obtained from the photocurable resin composition, the (meth)acrylate monomer (A) preferably contains one or more selected from the group consisting of monofunctional (meth)acrylate monomers (A1) and difunctional or higher functional (meth)acrylate monomers (A2).

[0018] From the viewpoint of further reducing surface unevenness of the optical molded body, the content of the monofunctional (meth)acrylate monomer (A1) in the photocurable resin composition of this embodiment is preferably 0 parts by mass or more and 99 parts by mass or less, more preferably 10 parts by mass or more and 95 parts by mass or less, even more preferably 30 parts by mass or more and 90 parts by mass or less, even more preferably 50 parts by mass or more and 90 parts by mass or less, even more preferably 60 parts by mass or more and 85 parts by mass or less, and even more preferably 70 parts by mass or more and 85 parts by mass or less, when the total content of the (meth)acrylate monomer (A) is taken as 100 parts by mass.

[0019] From the viewpoint of further reducing surface unevenness of the optical molded body, the content of the difunctional or higher (meth)acrylate monomer (A2) in the photocurable resin composition of this embodiment is preferably 1 part by mass or more and 100 parts by mass or less, more preferably 5 parts by mass or more and 90 parts by mass or less, even more preferably 10 parts by mass or more and 70 parts by mass or less, even more preferably 10 parts by mass or more and 50 parts by mass or less, even more preferably 15 parts by mass or more and 40 parts by mass or less, and even more preferably 15 parts by mass or more and 30 parts by mass or less, when the total content of the (meth)acrylate monomer (A) is taken as 100 parts by mass.

[0020] In the photocurable resin composition of this embodiment, the mass ratio of the content of the monofunctional (meth)acrylate monomer (A1) to the content of the difunctional or higher functional (meth)acrylate monomer (A2) is preferably 0.0 or more, more preferably 0.1 or more and 10.0 or less, even more preferably 0.5 or more and 8.0 or less, even more preferably 1.0 or more and 7.0 or less, even more preferably 1.5 or more and 6.0 or less, even more preferably 2.0 or more and 5.0 or less, and even more preferably 3.0 or more and 4.5 or less, from the viewpoint of further reducing surface unevenness of the optical molded body.

[0021] From the viewpoint of further reducing the surface unevenness of the optical molded body, the (meth)acrylate monomer (A) preferably contains a (meth)acrylate monomer having an alicyclic skeleton. From the viewpoint of further reducing the surface unevenness of the optical molded body, the (meth)acrylate monomer having an alicyclic skeleton more preferably contains one or more skeletons selected from the group consisting of an adamantane skeleton, a norbornane skeleton, and a dicyclopentadiene skeleton. From the viewpoint of further reducing the surface unevenness of the optical molded body, the (meth)acrylate monomer having an alicyclic skeleton further preferably contains one or more skeletons selected from the group consisting of dicyclopentanyl (meth)acrylate and isobornyl (meth)acrylate.

[0022] From the viewpoint of further reducing surface unevenness of the optical molded body, the content of the (meth)acrylate monomer having an alicyclic skeleton in the photocurable resin composition of this embodiment is, when the total content of the (meth)acrylate monomer (A) is taken as 100 parts by mass, preferably 30 parts by mass or more and 100 parts by mass or less, more preferably 40 parts by mass or more and 100 parts by mass or less, even more preferably 45 parts by mass or more and 100 parts by mass or less, even more preferably 50 parts by mass or more and 100 parts by mass or less, even more preferably 60 parts by mass or more and 100 parts by mass or less, even more preferably 70 parts by mass or more and 100 parts by mass or less, even more preferably 75 parts by mass or more and 95 parts by mass or less, and even more preferably 80 parts by mass or more and 90 parts by mass or less.

[0023] From the viewpoint of further reducing surface unevenness of the optical molded body, the (meth)acrylate monomer (A) preferably contains a (meth)acrylate monomer having a linear hydrocarbon skeleton, and more preferably contains 1,12-dodecanediol di(meth)acrylate.

[0024] From the viewpoint of further reducing surface unevenness of the optical molded body, the content of the (meth)acrylate monomer (A) in the photocurable resin composition of this embodiment is preferably 80% by mass or more and less than 100% by mass, more preferably 85% by mass or more and 99% by mass or less, even more preferably 90% by mass or more and 98% by mass or less, even more preferably 92% by mass or more and 97% by mass or less, and even more preferably 93% by mass or more and 96% by mass or less, when the entire photocurable resin composition is taken as 100% by mass.

[0025] <Monofunctional (meth)acrylate Monomer (A1)> The monofunctional (meth)acrylate monomer (A1) includes, for example, one or more monomers selected from the group consisting of chain monofunctional (meth)acrylates such as aromatic ring monofunctional (meth)acrylates; alicyclic monofunctional (meth)acrylates; linear monofunctional (meth)acrylates (including, for example, monofunctional (meth)acrylate monomers having a linear hydrocarbon skeleton) and branched monofunctional (meth)acrylates.

[0026] The monofunctional (meth)acrylate monomer (A1) is preferably isobornyl (meth)acrylate, dicyclopentanyl (meth)acrylate (e.g., GM81HDA, manufactured by Kokusei Chemical Co., Ltd.), 3,3,5-trimethylcyclohexyl (meth)acrylate, 4-tert-butylcyclohexyl (meth)acrylate, dicyclopentenyl (meth)acrylate (e.g., FA-511AS, manufactured by Hitachi Chemical Co., Ltd.), dicyclopentenyloxyethyl (meth)acrylate, tetrahydrofurfuryl (meth)acrylate, 2-hydroxyethyl (meth)acrylate, methyl ... Acrylate, 4-hydroxybutyl (meth)acrylate, isobutyl (meth)acrylate, t-butyl (meth)acrylate, isooctyl (meth)acrylate, 2-methoxyethyl (meth)acrylate, methoxytriethylene glycol (meth)acrylate, 2-ethoxyethyl (meth)acrylate, 3-methoxybutyl (meth)acrylate, ethoxyethyl (meth)acrylate, butoxyethyl (meth)acrylate, ethoxydiethylene glycol (meth)acrylate, methoxydixylethyl (meth)acrylate, ethyl Diglycol (meth)acrylate, cyclic trimethylolpropane formal mono(meth)acrylate, imide (meth)acrylate, isoamyl (meth)acrylate, ethoxylated succinic acid (meth)acrylate, trifluoroethyl (meth)acrylate, ω-carboxypolycaprolactone mono(meth)acrylate, cyclohexyl (meth)acrylate, 2-(2-ethoxyethoxy)ethyl (meth)acrylate, stearyl (meth)acrylate, isostearyl (meth)acrylate (e.g., S-1800A, Shin-Nakamura Chemical Co., Ltd.) manufactured by Osaka Organic Chemical Industry Co., Ltd.), diethylene glycol monobutyl ether (meth)acrylate, lauryl (meth)acrylate (e.g., LA, manufactured by Osaka Organic Chemical Industry Co., Ltd.), isodecyl (meth)acrylate, octyl / decyl (meth)acrylate, tridecyl (meth)acrylate, caprolactone (meth)acrylate, ethoxylated (4) nonylphenol (meth)acrylate, methoxypolyethylene glycol (350) mono(meth)acrylate, methoxypolyethylene glycol (550) mono(meth)acrylate, phenoxyethyl (meth)acrylate,Benzyl (meth)acrylate, methylphenoxyethyl (meth)acrylate, caprolactone-modified tetrahydrofurfuryl (meth)acrylate, tribromophenyl (meth)acrylate, ethoxylated tribromophenyl (meth)acrylate, 2-phenoxyethyl (meth)acrylate, ethylene oxide adduct of 2-phenoxyethyl (meth)acrylate, propylene oxide adduct of 2-phenoxyethyl (meth)acrylate, phenoxydiethylene glycol (meth) acrylate, 2-hydroxy-3-phenoxypropyl (meth)acrylate, 3-methacryloyloxymethyl cyclohexene oxide, 3-(meth)acryloyloxymethyl cyclohexene oxide, ethoxylated-o-phenylphenol (meth)acrylate (for example, A-LEN-10, manufactured by Shin-Nakamura Chemical Co., Ltd.), 2-methacryloyloxy-2-methyladamantane, and 2-methacryloyloxy-2-ethyladamantane.

[0027] From the viewpoint of further reducing surface unevenness of the optical molded body, the monofunctional (meth)acrylate monomer (A1) preferably contains a monofunctional (meth)acrylate monomer having an alicyclic skeleton, more preferably contains dicyclopentanyl (meth)acrylate, and even more preferably contains dicyclopentanyl methacrylate.

[0028] <Difunctional or higher functional (meth)acrylate monomer (A2)> The difunctional or higher functional (meth)acrylate monomer (A2) preferably includes one or more selected from the group consisting of alicyclic difunctional (meth)acrylate monomers and linear difunctional (meth)acrylate monomers.

[0029] The alicyclic bifunctional (meth)acrylate monomer is a bifunctional (meth)acrylate monomer having an alicyclic hydrocarbon structure in its molecular structure. From the viewpoint of improving heat resistance, the number of carbon atoms in the alicyclic hydrocarbon structure is preferably 4 or more and 14 or less, more preferably 5 or more and 12 or less, and even more preferably 6 or more and 10 or less. The alicyclic hydrocarbon structure may be a saturated hydrocarbon structure or an unsaturated hydrocarbon structure. From the viewpoint of improving heat resistance, the alicyclic hydrocarbon structure is preferably a saturated hydrocarbon structure.

[0030] The alicyclic hydrocarbon structure may be a monocyclic hydrocarbon structure, or a polycyclic hydrocarbon structure such as a fused ring hydrocarbon structure or a bridged ring hydrocarbon structure. The alicyclic bifunctional (meth)acrylate monomer may contain a group containing such an alicyclic hydrocarbon structure in its molecular structure, and preferably contains a divalent group containing an alicyclic hydrocarbon structure. Specific examples of the monocyclic hydrocarbon group include groups having a cycloalkane structure such as a cyclohexylene group or a cyclohexyl group; and groups having a cycloalkene skeleton such as a cyclodecatriene diyl group or a cyclodecatriene group. Specific examples of the polycyclic hydrocarbon group include groups having a dicyclopentadiene skeleton such as a tricyclodecanediyl group, a dicyclopentanyl group, or a dicyclopentenyl group; groups having a norbornane skeleton such as a norbornanediyl group, an isobornanediyl group, a norbornyl group, or an isobornyl group; and groups having an adamantane skeleton such as an adamantanediyl group or an adamantyl group.

[0031] The cyclic hydrocarbon group in the alicyclic bifunctional (meth)acrylate monomer is preferably a group having a dicyclopentadiene skeleton, from the viewpoint of further reducing surface unevenness of the optical molded body.

[0032] Furthermore, from the viewpoint of reducing cure shrinkage during molding of the optical molded body, the alicyclic bifunctional (meth)acrylate monomer preferably contains tricyclodecane dimethanol di(meth)acrylate, more preferably is tricyclodecane dimethanol di(meth)acrylate, and even more preferably is tricyclodecane dimethanol dimethacrylate (e.g., DCP, manufactured by Shin-Nakamura Chemical Co., Ltd.).

[0033] The linear bifunctional (meth)acrylate monomer is a (meth)acrylate having a linear structure in its molecular structure and two (meth)acryloyl groups. The linear structure preferably contains a divalent linear hydrocarbon group from the viewpoint of improving crack resistance during molding of the optical molded body. The number of carbon atoms in the divalent linear hydrocarbon group is, for example, 1 or more, preferably 2 or more, and more preferably 4 or more, from the viewpoint of reducing deviation in the liquid amount due to volatilization of the monomer during molding of the optical molded body. Furthermore, from the viewpoint of improving heat resistance, the number of carbon atoms in the divalent linear hydrocarbon group is preferably 20 or less, more preferably 14 or less.

[0034] Specific examples of the linear bifunctional (meth)acrylate monomer include di(meth)acrylates of alkanediols. The linear bifunctional (meth)acrylate monomer is preferably 1,6-hexanediol di(meth)acrylate (e.g., A-HD-N, manufactured by Shin-Nakamura Chemical Co., Ltd.; HD-N, manufactured by Shin-Nakamura Chemical Co., Ltd.), 1,9-nonanediol di(meth)acrylate (e.g., A-NOD-N, manufactured by Shin-Nakamura Chemical Co., Ltd.; Light Acrylate 1,9ND-A, manufactured by Kyoeisha Chemical Co., Ltd.; NOD-N, manufactured by Shin-Nakamura Chemical Co., Ltd.; Light Acrylate 1,9-ND-M, manufactured by Kyoeisha Chemical Co., Ltd.), 1,10-decanediol di(meth)acrylate (e.g., A-DOD-N, manufactured by Shin-Nakamura Chemical Co., Ltd.; DOD-N, manufactured by Shin-Nakamura Chemical Co., Ltd.), 1,12-dodecanediol di(meth)acrylate (e.g., A-DOD-N, manufactured by Shin-Nakamura Chemical Co., Ltd.; DOD-N, manufactured by Shin-Nakamura Chemical Co., Ltd.), or 1,12-dodecanediol di(meth)acrylate (e.g., A-DOD-N, manufactured by Shin-Nakamura Chemical Co., Ltd.; DOD-N, manufactured by Shin-Nakamura Chemical Co., Ltd.). The di(meth)acrylate may comprise one or more selected from the group consisting of (meth)acrylates (e.g., DDD, manufactured by Shin-Nakamura Chemical Co., Ltd.; SR262, manufactured by Arkema), ethylene glycol di(meth)acrylates (e.g., SR206NS, manufactured by Arkema), triethylene glycol di(meth)acrylates (e.g., SR272, manufactured by Arkema), polyethylene glycol di(meth)acrylates (e.g., A-400, manufactured by Shin-Nakamura Chemical Co., Ltd.), 1,3-butanediol di(meth)acrylates (e.g., BG, manufactured by Shin-Nakamura Chemical Co., Ltd.), and 1,4-butanediol di(meth)acrylates (e.g., BD, manufactured by Shin-Nakamura Chemical Co., Ltd.).

[0035] The bifunctional or higher functional (meth)acrylate monomer (A2) preferably has an alicyclic skeleton, from the viewpoint of further reducing surface unevenness of the optical molded body. The bifunctional or higher functional (meth)acrylate monomer (A2) more preferably contains tricyclodecane dimethanol di(meth)acrylate, and more preferably contains tricyclodecane dimethanol dimethacrylate, from the viewpoint of further reducing surface unevenness of the optical molded body.

[0036] The di- or higher functional (meth)acrylate monomer (A2) preferably has a straight-chain hydrocarbon skeleton, from the viewpoint of further reducing surface unevenness of the optical molded body. From the viewpoint of further reducing surface unevenness of the optical molded body, the di- or higher functional (meth)acrylate monomer (A2) more preferably contains 1,12-dodecanediol di(meth)acrylate, and even more preferably contains 1,12-dodecanediol dimethacrylate.

[0037] <Antioxidant (B)> The photocurable resin composition of this embodiment may further include an antioxidant (B). The antioxidant (B) is not particularly limited, and known antioxidants can be used. The antioxidant (B) includes, for example, one or more selected from the group consisting of phenol-based antioxidants, phosphorus-based antioxidants, sulfur-based antioxidants, hindered amine-based antioxidants, and thioether-based antioxidants.

[0038] Examples of phenolic antioxidants include 2,6-di-t-butylhydroxytoluene and pentaerythritol tetrakis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate]. Examples of commercially available phenolic antioxidants include AO-20, AO-30, AO-40, AO-50, AO-60, and AO-80 from the Adeka STAB series manufactured by ADEKA Corporation.

[0039] Examples of phosphorus-based antioxidants include phosphines such as trialkylphosphine and triarylphosphine, trialkyl phosphites, triaryl phosphites, etc. Commercially available phosphorus-based antioxidants include PEP-4C, PEP-8, PEP-24G, PEP-36, HP-10, 260, 522A, 329K, 1178, 1500, 135A, and 3010 from the Adeka STAB series manufactured by ADEKA Corporation.

[0040] Examples of sulfur-based antioxidants include dilauryl 3,3-thiodipropionate, dimyristyl 3,3′-thiodipropionate, distearyl 3,3-thiodipropionate, laurylstearyl 3,3-thiodipropionate, pentaerythritol-tetrakis-(β-lauryl-thio-propionate), 3,9-bis(2-dodecylthioethyl)-2,4,8,10-tetraoxaspiro[5,5]undecane, and the like.

[0041] Examples of hindered amine antioxidants include bis(1,2,2,6,6-pentamethyl-4-piperidinyl)sebacate, methyl(1,2,2,6,6-pentamethyl-4-piperidinyl)sebacate, 2,4-bis[N-butyl-N-(1-cyclohexyloxy-2,2,6,6-tetramethylpiperidin-4-yl)amino]-6-(2-hydroxyethylamine)-1,3,5-triazine, decanedioic acid bis(2,2,6,6-tetramethyl-1-(octyloxy)-4-piperidinyl)ester, and bis(1,2,2,6,6-pentamethyl-4-piperidyl)sebacate. Examples of commercially available hindered amine antioxidants include AL-72 from the Adekastab series manufactured by ADEKA Corporation, and 111FDL, 123, 144, 152, 292, and 5100 from the TINUVIN series manufactured by BASF.

[0042] Examples of thioether antioxidants include ditridecyl 3,3'-thiobispropionate and 2,2-bis[[3-(dodecylthio)-1-oxopropyloxy]methyl]-1,3-propanediyl bis[3-(dodecylthio)propionic acid]. Examples of commercially available thioether antioxidants include AO-26, AO-412S, and AO-503A from the Adeka STAB series manufactured by ADEKA Corporation.

[0043] From the viewpoint of further reducing the coloration of the optical molded body, the antioxidant (B) preferably contains one or more antioxidants selected from the group consisting of phenolic antioxidants and thioether antioxidants. From the viewpoint of further reducing the coloration of the optical molded body, the antioxidant (B) more preferably contains one or more antioxidants selected from the group consisting of 2,2-bis[[3-(dodecylthio)propionic acid]3-oxopropyloxy]methyl]-1,3-propanediyl (e.g., Adekastab AO-412S, manufactured by ADEKA Corporation) and pentaerythritol tetrakis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate] (e.g., Adekastab AO-60, manufactured by ADEKA Corporation).

[0044] From the viewpoint of further reducing coloration of the optical molded body, the content of the antioxidant (B) in the photocurable resin composition of this embodiment is preferably 0.010 parts by mass or more and 10 parts by mass or less, more preferably 0.050 parts by mass or more and 5.0 parts by mass or less, even more preferably 0.10 parts by mass or more and 3.0 parts by mass or less, even more preferably 0.20 parts by mass or more and 2.0 parts by mass or less, and even more preferably 0.50 parts by mass or more and 1.5 parts by mass or less, when the total content of the (meth)acrylate monomer (A) is taken as 100 parts by mass.

[0045] From the viewpoint of further reducing the coloration of the optical molded body, the content of the antioxidant (B) in the photocurable resin composition of this embodiment is preferably 0.010% by mass or more and 5.0% by mass or less, more preferably 0.050% by mass or more and 4.0% by mass or less, even more preferably 0.10% by mass or more and 3.0% by mass or less, even more preferably 0.50% by mass or more and 2.0% by mass or less, and even more preferably 0.90% by mass or more and 1.0% by mass or less, when the total amount of solids in the photocurable resin composition (the total amount of components that remain as solids when cured) is taken as 100% by mass.

[0046] <Photopolymerization initiator (C)> The photocurable resin composition of the present embodiment may further contain a photopolymerization initiator (C). The photopolymerization initiator (C) is not particularly limited, and a known polymerization initiator can be used.

[0047] From the viewpoint of stably forming an optical molded body at low temperatures, the photopolymerization initiator (C) preferably contains a photoradical polymerization initiator. The photoradical polymerization initiator is a compound that generates radicals upon irradiation with ultraviolet light or visible light. Examples of the photoradical polymerization initiator include acylphosphine oxide-based initiators, oxyphenylacetic acid ester-based initiators, benzoylformic acid-based initiators, and hydroxyphenyl ketone-based initiators.

[0048] Examples of the photopolymerization initiator (C) include benzophenone, Michler's ketone, 4,4'-bis(diethylamino)benzophenone, xanthone, thioxanthone, isopropylxanthone, 2,4-diethylthioxanthone, 2-ethylanthraquinone, acetophenone, 2-hydroxy-2-methyl-4'-isopropylpropiophenone, isopropyl benzoin ether, isobutyl benzoin ether, 2,2-diethoxyacetophenone, 2,2-dimethoxy-2-phenylacetophenone, camphorquinone, benzanthrone, 4- Ethyl dimethylaminobenzoate, isoamyl 4-dimethylaminobenzoate, 4,4'-di(t-butylperoxycarbonyl)benzophenone, 3,4,4'-tri(t-butylperoxycarbonyl)benzophenone, 3,3',4,4'-tetra(t-butylperoxycarbonyl)benzophenone, 3,3',4,4'-tetra(t-hexylperoxycarbonyl)benzophenone, 3,3'-di(methoxycarbonyl)-4,4'-di(t-butylperoxycarbonyl)benzophenone, 3,4'-di(methoxycarbonyl)-4,3' -di(t-butylperoxycarbonyl)benzophenone, 4,4'-di(methoxycarbonyl)-3,3'-di(t-butylperoxycarbonyl)benzophenone, 2-(4'-methoxystyryl)-4,6-bis(trichloromethyl)-s-triazine, 2-(3',4'-dimethoxystyryl)-4,6-bis(trichloromethyl)-s-triazine, 2-(2',4'-dimethoxystyryl)-4,6-bis(trichloromethyl)-s-triazine, 2-(2'-methoxystyryl)-4,6-bis(trichloromethyl)-s-triazine , 2-(4'-pentyloxystyryl)-4,6-bis(trichloromethyl)-s-triazine, 4-[p-N,N-di(ethoxycarbonylmethyl)]-2,6-di(trichloromethyl)-s-triazine, 1,3-bis(trichloromethyl)-5-(2'-chlorophenyl)-s-triazine, 1,3-bis(trichloromethyl)-5-(4'-methoxyphenyl)-s-triazine, 2-(p-dimethylaminostyryl)benzoxazole, 2-(p-dimethylaminostyryl)benzthiazole, 2-mercaptobenzothiazole, 3,3'-Carbonylbis(7-diethylaminocoumarin), 2-(o-chlorophenyl)-4,4',5,5'-tetraphenyl-1,2'-biimidazole, 2,2'-bis(2-chlorophenyl)-4,4',5,5'-tetrakis(4-ethoxycarbonylphenyl)-1,2'-biimidazole, 2,2'-bis(2,4-dichlorophenyl)-4,4',5,5'-tetraphenyl-1,2'-biimidazole, 2,2'-bis(2,4-dibromophenyl)-4,4',5,5'-tetraphenyl-1,2'-biimidazole 2,2'-bis(2,4,6-trichlorophenyl)-4,4',5,5'-tetraphenyl-1,2'-biimidazole, 3-(2-methyl-2-dimethylaminopropionyl)carbazole, 3,6-bis(2-methyl-2-morpholinopropionyl)-9-n-dodecylcarbazole, bis(η5-2,4-cyclopentadien-1-yl)-bis(2,6-difluoro-3-(1H-pyrrol-1-yl)-phenyl)titanium, 1-hydroxycyclohexyl phenyl ketone, 2-hydroxy-2-methyl-1-fluoropropanol phenyl-1-propanone, 1-[4-(2-hydroxyethoxy)-phenyl]-2-hydroxy-2-methyl-1-propanone, 2-hydroxy-1-{4-[4-(2-hydroxy-2-methyl-propionyl)-benzyl]phenyl}-2-methyl-1-propanone, 2-methyl-1-[4-(methylthio)phenyl]-2-morpholino-1-propanone, 2-(dimethylamino)-1-(4-morpholinophenyl)-2-benzyl-1-butanone, 2-(dimethylamino)-2-[(4-methylphenyl)methyl]-1-[4 -(4-morpholinyl)phenyl]-1-butanone, oxy-phenyl-acetic acid 2-[2-oxo-2-phenyl-acetoxy-ethoxy]-ethyl ester, oxy-phenyl-acetic acid 2-[2-hydroxy-ethoxy]-ethyl ester, methyl benzoylformate, bis(2,4,6-trimethylbenzoyl)phenylphosphine oxide, 2,4,6-trimethylbenzoyldiphenylphosphine oxide, 2,4,6-trimethylbenzoyldiphenylphosphinic acid ester, 1-[4-(phenylthio)phenyl]-1,2-octanedione 2-(O-benzoyloxime)], 1-[9-ethyl-6-(2-methylbenzoyl)-9H-carbazol-3-yl]-ethanone-1-(O-acetyloxime), etc.

[0049] From the viewpoint of further reducing surface unevenness of the optical molded body, the photopolymerization initiator (C) preferably contains a hydroxyphenyl ketone initiator, and more preferably contains 1-hydroxycyclohexyl phenyl ketone (for example, Omnirad 184, manufactured by IGM Resins).

[0050] The content of the photopolymerization initiator (C) in the photocurable resin composition of this embodiment is preferably 0.10 parts by mass or more, more preferably 0.50 parts by mass or more, even more preferably 1.0 parts by mass or more, even more preferably 2.0 parts by mass or more, and even more preferably 3.0 parts by mass or more, when the content of the (meth)acrylate monomer (A) is taken as 100 parts by mass, from the viewpoint of further reducing surface unevenness of the optical molded body. The content of the photopolymerization initiator (C) in the photocurable resin composition of this embodiment is preferably 10 parts by mass or less, more preferably 8.0 parts by mass or less, even more preferably 6.0 parts by mass or less, even more preferably 5.0 parts by mass or less, and even more preferably 4.5 parts by mass or less, when the content of the (meth)acrylate monomer (A) is taken as 100 parts by mass, from the viewpoint of improving the thickness uniformity of the photocurable resin composition when cured. From the viewpoint of further reducing surface unevenness of the optical molded body and improving the thickness uniformity of the photocurable resin composition when cured, the content of the photopolymerization initiator (C) in the photocurable resin composition of this embodiment is preferably 0.10 parts by mass or more and 10 parts by mass or less, more preferably 0.50 parts by mass or more and 8.0 parts by mass or less, even more preferably 1.0 parts by mass or more and 6.0 parts by mass or less, even more preferably 2.0 parts by mass or more and 5.0 parts by mass or less, and even more preferably 3.0 parts by mass or more and 4.5 parts by mass or less, when the content of the (meth)acrylate monomer (A) is taken as 100 parts by mass.

[0051] From the viewpoint of further reducing surface unevenness of the optical molded body, the content of the photopolymerization initiator (C) in the photocurable resin composition of this embodiment is preferably 0.10% by mass or more and 10% by mass or less, more preferably 1.0% by mass or more and 8.0% by mass or less, even more preferably 2.0% by mass or more and 6.0% by mass or less, even more preferably 3.0% by mass or more and 5.0% by mass or less, and even more preferably 3.5% by mass or more and 4.5% by mass or less, when the total amount of solids in the photocurable resin composition (the total amount of components that remain as solids when cured) is taken as 100% by mass.

[0052] <Light Stabilizer (D)> The photocurable resin composition of the present embodiment may further contain a light stabilizer (D). The light stabilizer (D) is not particularly limited, and a known light stabilizer can be used. By containing the light stabilizer (D), the coloration resistance of the photocurable resin composition can be improved.

[0053] The light stabilizer (D) preferably contains a hindered amine-based light stabilizer from the viewpoint of further improving coloration resistance.

[0054] Examples of hindered amine light stabilizers include methacrylic acid (1,2,2,6,6-pentamethyl-piperidin-4-yl), decanedioic acid bis(2,2,6,6-tetramethyl-1(octyloxy)-4-piperidinyl) ester, a mixture of 70% by mass of a reaction product of 1,1-dimethylethyl hydroperoxide and octane and 30% by mass of polypropylene, bis(1,2,2,6,6-pentamethyl-4-piperidyl)[[3,5-bis(1,1-dimethylethyl)-4-hydroxyphenyl]methyl]butylmalonate, bis(1,2,2,6,6-pentamethyl-4-piperidyl)sebacate, and a mixture of methyl-1,2,2,6,6-pentamethyl-4-piperidylsebacate. a mixture of 2,2,6,6-tetramethyl-4-piperidyl-1,2,3,4-butanetetracarboxylate, bis(2,2,6,6-tetramethyl-4-piperidyl)sebacate, tetrakis(2,2,6,6-tetramethyl-4-piperidyl)-1,2,3,4-butanetetracarboxylate, tetrakis(1,2,2,6,6-pentamethyl-4-piperidyl)-1,2,3,4-butanetetracarboxylate, a mixture of 2,2,6,6-tetramethyl-4-piperidyl-1,2,3,4-butanetetracarboxylate and tridecyl-1,2,3,4-butanetetracarboxylate, and a mixture of 1,2,2,6,6-pentamethyl-4-piperidyl-1,2,3,4-butanetetracarboxylate and tridecyl-1,2,3,4-butanetetracarboxylate.

[0055] From the viewpoint of further improving coloration resistance, the light stabilizer (D) preferably contains 1,2,2,6,6-pentamethyl-4-piperidyl methacrylate (for example, Adekastab LA-82, manufactured by ADEKA Corporation).

[0056] From the viewpoint of further improving the coloration resistance of the optical molded body, the content of the light stabilizer (D) in the photocurable resin composition of this embodiment is preferably 0.010 parts by mass or more and 5 parts by mass or less, more preferably 0.050 parts by mass or more and 1.0 part by mass or less, even more preferably 0.060 parts by mass or more and 0.50 parts by mass or less, even more preferably 0.080 parts by mass or more and 0.20 parts by mass or less, and even more preferably 0.090 parts by mass or more and 0.11 parts by mass or less, when the total content of the (meth)acrylate monomer (A) is taken as 100 parts by mass.

[0057] From the viewpoint of further reducing surface unevenness of the optical molded body, the content of the light stabilizer (D) in the photocurable resin composition of this embodiment is preferably 0.0010% by mass or more, more preferably 0.0050% by mass or more, even more preferably 0.010% by mass or more, even more preferably 0.050% by mass or more, even more preferably 0.090% by mass or more, even more preferably 0.094% by mass or more, and even more preferably 0.095% by mass or more, when the total amount of solids in the photocurable resin composition (the total amount of components that remain as solids when cured) is taken as 100% by mass. From the viewpoint of reducing bleed-out, the content of the light stabilizer (D) in the photocurable resin composition of this embodiment is preferably 1.0% by mass or less, more preferably 0.60% by mass or less, even more preferably 0.50% by mass or less, even more preferably 0.40% by mass or less, and still more preferably 0.30% by mass or less, when the total amount of solids in the photocurable resin composition (the total amount of components that remain as solids when cured) is taken as 100% by mass. From the viewpoint of further reducing surface unevenness of the optical molded body and reducing bleed-out, the content of the light stabilizer (D) in the photocurable resin composition of this embodiment is preferably 0.0010% by mass or more and 1.0% by mass or less, more preferably 0.0050% by mass or more and 0.60% by mass or less, even more preferably 0.010% by mass or more and 0.50% by mass or less, even more preferably 0.050% by mass or more and 0.40% by mass or less, even more preferably 0.090% by mass or more and 0.30% by mass or less, even more preferably 0.094% by mass or more and 0.20% by mass or less, and even more preferably 0.095% by mass or more and 0.10% by mass or less, when the total amount of solids in the photocurable resin composition (the total amount of components that remain as solids when cured) is taken as 100% by mass.

[0058] <Other Components> The photocurable resin composition may include, as specific examples of other components besides the polymerizable compound (e.g., the (meth)acrylate monomer (A)), the antioxidant (B), the photopolymerization initiator (C), and the light stabilizer (D), one or more selected from the group consisting of a filler, a curing accelerator, a plasticizer, a heat stabilizer, a flame retardant, an antistatic agent, an antifoaming agent, a silane coupling agent, an ultraviolet absorber, a surfactant, and a leveling agent.

[0059] <Method for producing photocurable resin composition> The photocurable resin composition according to the present invention can be obtained by mixing a polymerizable compound (e.g., a (meth)acrylate monomer (A)) and, if necessary, other components such as an antioxidant (B), a photopolymerization initiator (C), or a light stabilizer (D) by a conventionally known method.

[0060] <Physical Properties of Photocurable Resin Composition> Next, the physical properties of the photocurable resin composition will be described.

[0061] The absorbance A of the photocurable resin composition of this embodiment at a wavelength of 405 nm, measured according to the following <Measurement Method> ４０５ This article explains:

[0062] Absorbance A ４０５ From the viewpoint of reducing surface unevenness of the optical molded body, the absorbance A is 0.300 or less, preferably 0.250 or less, more preferably 0.200 or less, even more preferably 0.150 or less, even more preferably 0.100 or less, even more preferably 0.050 or less, and even more preferably 0.030 or less. ４０５ From the viewpoint of enabling the photocurable resin composition to be cured with light having a wavelength of 405 nm, the absorbance A is preferably 0.000 or more, more preferably 0.005 or more, even more preferably 0.010 or more, and still more preferably 0.015 or more. ４０５From the viewpoint of reducing surface unevenness of the optical molded body, is preferably 0.000 or more and 0.300 or less, more preferably 0.005 or more and 0.250 or less, even more preferably 0.010 or more and 0.200 or less, even more preferably 0.010 or more and 0.150 or less, even more preferably 0.010 or more and 0.100 or less, even more preferably 0.010 or more and 0.050 or less, and even more preferably 0.015 or more and 0.030 or less.

[0063] <Measurement Method> A sample was prepared by dissolving the photocurable resin composition in isopropanol at a mass ratio of 7:93. The sample was then placed in a sample cell with an optical path length of 10 mm and exposed to incident light at a wavelength of 405 nm and an intensity of I ０ The light intensity I of the light transmitted through the sample cell is measured. After the measurement, the absorbance A at a wavelength of 405 nm is calculated using the following equation (3). ４０５ (3): A ４０５ = -log １０ (I / I ０ Here, in this embodiment, the <measurement method> can be more specifically carried out according to the method described in the examples.

[0064] <Uses of Photocurable Resin Composition> Next, uses of the photocurable resin composition will be described.

[0065] The photocurable resin composition of this embodiment can reduce surface unevenness of an optical molded body, and therefore can be used in methods for forming an optical molded body, such as injection molding, compression molding, injection compression molding, extrusion molding, solution casting, and casting methods. In particular, the photocurable resin composition of this embodiment can be used in casting methods.

[0066] Since the photocurable resin composition of this embodiment can reduce surface unevenness of an optical molded body, the use of the optical molded body molded from the photocurable resin composition is not particularly limited, and the optical molded body can be used for a variety of purposes.

[0067] The photocurable resin composition of this embodiment can be preferably used, for example, for lenses, including, for example, one or more lenses selected from the group consisting of spherical lenses, aspherical lenses, biconvex lenses, plano-convex lenses, convex meniscus lenses, biconcave lenses, plano-concave lenses, and concave meniscus lenses.

[0068] The photocurable resin composition of this embodiment can be used, for example, more preferably, for one or more lenses selected from the group consisting of lenses for virtual reality devices (VR lenses), lenses for mixed reality devices (MR lenses), lenses for augmented reality devices (AR lenses), lenses for cross reality devices (xR lenses), and lenses for head-mounted displays (HMD lenses).

[0069] The photocurable resin composition of the present embodiment can be preferably used, for example, for a display cover (hereinafter also referred to as a cover display). The cover display includes, for example, one or more types selected from the group consisting of a front cover display and a full cover display.

[0070] The photocurable resin composition of this embodiment can be used, for example, more preferably, for one or more cover displays selected from the group consisting of cover displays for virtual reality devices (cover displays for VR devices), cover displays for mixed reality devices (cover displays for MR devices), cover displays for augmented reality devices (cover displays for AR devices), cover displays for cross reality devices (cover displays for xR devices), and cover displays for head-mounted displays (cover displays for HMDs).

[0071] (Optical Molded Body) The optical molded body of this embodiment includes a cured product of the photocurable resin composition of this embodiment. The optical molded body of this embodiment can be manufactured using the photocurable resin composition of this embodiment. The optical molded body can be manufactured from the photocurable resin composition of this embodiment by any method, such as injection molding, compression molding, injection compression molding, extrusion molding, solution casting, and casting. The optical molded body of this embodiment may be manufactured using the photocurable resin composition of this embodiment by the method for manufacturing an optical molded body of this embodiment described below.

[0072] The optical molded body of the present embodiment includes a lens, for example, one or more lenses selected from the group consisting of a spherical lens, an aspherical lens, a biconvex lens, a plano-convex lens, a convex meniscus lens, a biconcave lens, a plano-concave lens, and a concave meniscus lens.

[0073] The lens of this embodiment includes one or more lenses selected from the group consisting of lenses for virtual reality devices (VR lenses), lenses for mixed reality devices (MR lenses), lenses for augmented reality devices (AR lenses), lenses for cross reality devices (xR lenses), and lenses for head-mounted displays (HMD lenses).

[0074] The optical molded body of this embodiment includes a display cover (cover display). The cover display includes, for example, one or more types selected from the group consisting of a front cover display and a full cover display.

[0075] The cover display of this embodiment includes one or more types selected from the group consisting of a cover display for a virtual reality device (a cover display for a VR device), a cover display for a mixed reality device (a cover display for an MR device), a cover display for an augmented reality device (a cover display for an AR device), a cover display for a cross reality device (a cover display for an xR device), and a cover display for a head-mounted display (a cover display for an HMD).

[0076] The maximum thickness portion of the optical molded body is the portion of the optical molded body where the thickness of the optical member is greatest. The position of the maximum thickness portion of the optical molded body is not particularly limited and can be set appropriately depending on the application, etc.

[0077] For example, the optical molded body of this embodiment preferably has a maximum thickness of 1.0 mm or more, more preferably a maximum thickness of 1.1 mm or more, even more preferably a maximum thickness of 1.2 mm or more, even more preferably a maximum thickness of 1.5 mm or more, even more preferably a maximum thickness of 2.0 mm or more, even more preferably a maximum thickness of 3.0 mm or more, even more preferably a maximum thickness of 4.0 mm or more, and even more preferably a maximum thickness of 5.0 mm or more.

[0078] For example, the optical molded body of this embodiment preferably has a maximum thickness of 20.0 mm or less, more preferably a maximum thickness of 19.9 mm or less, even more preferably a maximum thickness of 19.8 mm or less, even more preferably a maximum thickness of 19.5 mm or less, even more preferably a maximum thickness of 18.0 mm or less, even more preferably a maximum thickness of 17.0 mm or less, even more preferably a maximum thickness of 16.0 mm or less, and even more preferably a maximum thickness of 15.0 mm or less.

[0079] For example, the optical molded body of this embodiment preferably has a maximum thickness of 1.0 mm or more and 20.0 mm or less, more preferably a maximum thickness of 1.1 mm or more and 19.9 mm or less, even more preferably a maximum thickness of 1.2 mm or more and 19.8 mm or less, even more preferably a maximum thickness of 1.5 mm or more and 19.5 mm or less, even more preferably a maximum thickness of 2.0 mm or more and 19.0 mm or less, even more preferably a maximum thickness of 3.0 mm or more and 18.0 mm or less, even more preferably a maximum thickness of 4.0 mm or more and 17.0 mm or less, even more preferably a maximum thickness of 5.0 mm or more and 16.0 mm or less, and even more preferably a maximum thickness of 5.0 mm or more and 15.0 mm or less.

[0080] The photocurable resin composition of this embodiment can reduce surface unevenness of the optical molded body, and therefore can be applied to optical molded bodies having a thickness of 1.0 mm or more.

[0081] (Method for producing optical molded body) Hereinafter, each step of the method for producing an optical molded body of this embodiment and raw materials used in the method for producing an optical molded body of this embodiment will be described. Note that the photocurable resin composition used in the method for producing an optical molded body of this embodiment preferably includes the photocurable resin composition of this embodiment.

[0082] The method for producing an optical molded body of this embodiment includes the following steps. - Viscosity increasing step: The photocurable resin composition is irradiated with light using an irradiation device having a light source peak at a wavelength of 360 nm or more and 410 nm or less, thereby increasing the viscosity of the photocurable resin composition. - Curing step: After the viscosity increasing step, the photocurable resin composition is irradiated with light using an irradiation device having a light source peak at a wavelength of 360 nm or more and 410 nm or less, thereby curing the photocurable resin composition. The method for producing an optical molded body of this embodiment, having the above-mentioned configuration, can reduce surface unevenness of the optical molded body.

[0083] <Thickening Step> In the thickening step, the viscosity of the photocurable resin composition is increased by irradiating the photocurable resin composition with light using an irradiation device having a light source peak at a wavelength of 360 nm or more and 410 nm or less. The type and shape of the device used in the thickening step are not particularly limited, as they vary depending on the properties of the photocurable resin composition used in the optical molded body or the shape of the optical molded body. In addition, the curing conditions in the thickening step (such as the wavelength of the irradiated light, the intensity of the irradiated light, the irradiation time, or the atmosphere during irradiation (such as temperature, humidity, atmospheric pressure, or type of gas)) are not particularly limited, as they vary depending on the properties of the photocurable resin composition used in the optical molded body or the shape of the optical molded body.

[0084] From the viewpoint of reducing surface unevenness of the optical molded body, the light source peak of the irradiation device used in the thickening step of this embodiment exists at a wavelength of 360 nm or more and 410 nm or less, preferably 370 nm or more and 410 nm or less, more preferably 380 nm or more and 410 nm or less, even more preferably 390 nm or more and 410 nm or less, and even more preferably 400 nm or more and 410 nm or less.

[0085] In the thickening step of this embodiment, the irradiation intensity of irradiating the photocurable resin composition with light using an irradiation device having a light source peak at a wavelength of 360 nm to 410 nm is preferably 90 mW to 130 mW, more preferably 100 mW to 120 mW, even more preferably 105 mW to 115 mW, and even more preferably 110 mW, from the viewpoint of further reducing surface unevenness of the optical molded body. In other words, the thickening step of this embodiment includes a step of irradiating the photocurable resin composition with light using an irradiation device having a light source peak at a wavelength of 360 nm to 410 nm, from the viewpoint of further reducing surface unevenness of the optical molded body, at the above-mentioned irradiation intensity (preferably 90 mW to 130 mW, more preferably 100 mW to 120 mW, even more preferably 105 mW to 115 mW, and even more preferably 110 mW).

[0086] In the thickening step of this embodiment, the irradiation time for irradiating the photocurable resin composition with light using an irradiation device having a light source peak at a wavelength of 360 nm to 410 nm is preferably 1 second to 300 seconds, more preferably 10 seconds to 240 seconds, even more preferably 30 seconds to 120 seconds, even more preferably 45 seconds to 90 seconds, and even more preferably 50 seconds to 70 seconds, from the viewpoint of further reducing surface unevenness of the optical molded body. In other words, the thickening step of this embodiment includes a step of irradiating the photocurable resin composition with light using an irradiation device having a light source peak at a wavelength of 360 nm to 410 nm for the above-mentioned irradiation time (preferably 1 second to 300 seconds, more preferably 10 seconds to 240 seconds, even more preferably 30 seconds to 120 seconds, even more preferably 45 seconds to 90 seconds, and even more preferably 50 seconds to 70 seconds).

[0087] In the thickening step of this embodiment, the cumulative light amount of light irradiated onto the photocurable resin composition using an irradiation device having a light source peak at a wavelength of 360 nm or more and 410 nm or less is preferably 50 mJ or more and 20.0 J or less, more preferably 100 mJ or more and 15.0 J or less, even more preferably 1.0 J or more and 10.0 J or less, even more preferably 5.0 J or more and 8.0 J or less, and even more preferably 6.0 J or more and 7.0 J or less, from the viewpoint of further reducing surface unevenness of the optical molded body. In other words, from the viewpoint of further reducing surface unevenness of the optical molded body, the thickening step of this embodiment includes a step of irradiating the photocurable resin composition with light at the above-mentioned cumulative light amount (preferably 50 mJ or more and 20.0 J or less, more preferably 100 mJ or more and 15.0 J or less, even more preferably 1.0 J or more and 10.0 J or less, even more preferably 5.0 J or more and 8.0 J or less, and even more preferably 6.0 J or more and 7.0 J or less) using an irradiation device having a light source peak at a wavelength of 360 nm or more and 410 nm or less.

[0088] In the thickening step, the thickness of the photocurable resin composition is preferably 1.0 mm or more and 20.0 mm or less, more preferably 1.5 mm or more and 19.0 mm or less, even more preferably 2.0 mm or more and 18.0 mm or less, even more preferably 2.5 mm or more and 17.0 mm or less, even more preferably 2.7 mm or more and 16.0 mm or less, and even more preferably 2.9 mm or more and 15.0 mm or less, from the viewpoint of further reducing surface unevenness of the optical molded body.

[0089] <Curing Step> In the curing step, the photocurable resin composition is irradiated with light using an irradiation device having a light source peak at a wavelength of 360 nm or more and 410 nm or less, thereby curing the photocurable resin composition. The curing step is performed after the thickening step. The type and shape of the device used in the curing step are not particularly limited, as they vary depending on the properties of the photocurable resin composition used in the optical molded body or the shape of the optical molded body. In addition, the curing conditions in the curing step (such as the wavelength of the irradiated light, the intensity of the irradiated light, the irradiation time, or the atmosphere during irradiation (such as temperature, humidity, atmospheric pressure, or type of gas)) are not particularly limited, as they vary depending on the properties of the photocurable resin composition used in the optical molded body or the shape of the optical molded body.

[0090] The light irradiated onto the photocurable resin composition may be, for example, ultraviolet light. Examples of ultraviolet light include UVC (ultraviolet C) with a wavelength of 200 to 280 nm, UVB (ultraviolet B) with a wavelength of 280 to 315 nm, and UVA (ultraviolet A) with a wavelength of 315 to 405 nm. When ultraviolet light is used, a light source such as sunlight, a chemical lamp, a mercury lamp, a metal halide lamp, or a UVLED can be used.

[0091] From the viewpoint of improving the appearance of the obtained optical molded body, the irradiation intensity of the ultraviolet irradiation is preferably from 500 mW to 1000 mW, more preferably from 700 mW to 950 mW, even more preferably from 750 mW to 900 mW, and even more preferably from 800 mW to 850 mW. The irradiation intensity of the ultraviolet irradiation refers to the irradiation intensity of ultraviolet light.

[0092] From the viewpoint of improving the appearance of the obtained optical molded body, the cumulative light amount of ultraviolet irradiation is preferably from 30 J to 200 J, more preferably from 50 J to 150 J, even more preferably from 70 J to 120 J, and even more preferably from 90 J to 100 J. The cumulative light amount of ultraviolet irradiation represents the total cumulative light amount of ultraviolet rays.

[0093] The method for producing an optical molded body of this embodiment may further include the following steps: Coating step: a step of coating a lower mold for molding with a photocurable resin composition; Upper mold setting step: a step of setting an upper mold for molding on the photocurable resin composition.

[0094] <Coating Step> In the coating step, the photocurable resin composition is coated onto a lower mold for molding. The thickening step is preferably performed after the coating step, from the viewpoint of facilitating the coating of the photocurable resin composition.

[0095] In the upper mold setting step, an upper mold for molding is set on the photocurable resin composition. The upper mold setting step is preferably performed after the thickening step and before the curing step, from the viewpoint of reducing leakage of the photocurable resin composition from between the upper mold and the lower mold when the upper mold is set.

[0096] (Optical Device) The optical device of this embodiment includes the optical molded body of this embodiment. The type of the optical device of this embodiment is not particularly limited. Examples of the optical device of this embodiment include a virtual reality device (VR device), a mixed reality device (MR device), an augmented reality device (AR device), a cross reality device (xR device), and a head-mounted display (HMD device).

[0097] Although the embodiments of the present invention have been described above, these are merely examples of the present invention, and various other configurations may be adopted. Furthermore, the present invention is not limited to the above-described embodiments, and modifications and improvements that do not impair the effects of the present invention are included in the present invention.

[0098] The present embodiment will be described in detail below with reference to examples, etc. However, the present embodiment is not limited to the descriptions of these examples.

[0099] First, the materials used in each example are listed below. Polymerizable compound: (meth)acrylate monomer (A) Monofunctional (meth)acrylate monomer (A1): GM81HDA (dicyclopentanyl methacrylate, manufactured by Kunisei Chemical Co., Ltd.) Difunctional or higher functional (meth)acrylate monomer (A2) 1: DDD (1,12-dodecanediol dimethacrylate, manufactured by Shin-Nakamura Chemical Co., Ltd.) Difunctional or higher functional (meth)acrylate monomer (A2) 2: DCP (tricyclodecane dimethanol dimethacrylate, manufactured by Shin-Nakamura Chemical Co., Ltd.) Difunctional or higher functional (meth)acrylate monomer (A2) 3: A-DCP (tricyclodecane dimethanol diacrylate, manufactured by Shin-Nakamura Chemical Co., Ltd.) Antioxidant (B) Antioxidant 1: thioether-based antioxidant (2,2-bis[[3-(dodecylthio)propionic acid]3-(3-dodecylthio)-1-oxopropyloxy]methyl]-1,3-propanediyl, manufactured by ADEKA Corporation, product name: Adekastab AO-412S) (hereinafter also referred to as AO-412S). Antioxidant 2: phenol-based antioxidant (pentaerythritol tetrakis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate], manufactured by ADEKA Corporation, product name: Adekastab AO-60) (hereinafter also referred to as AO-60). Photopolymerization initiator (C): Photopolymerization initiator 1: photoradical polymerization initiator (1-hydroxycyclohexyl phenyl ketone, manufactured by IGM Resins, product name: Omnirad 184). Photopolymerization initiator 2: photoradical polymerization initiator (2,4,6-trimethylbenzoyldiphenylphosphine oxide, manufactured by IGM Resins, product name: Omnirad TPO H) Light stabilizer (D) Light stabilizer 1: hindered amine light stabilizer (1,2,2,6,6-pentamethyl-4-piperidyl methacrylate, manufactured by ADEKA Corporation, product name: Adekastab LA-82) (hereinafter also referred to as LA-82)

[0100] (Examples 1 to 5, Comparative Examples 1 to 4) Liquid photocurable resin compositions were obtained by blending the components to obtain the formulations shown in Table 1. The formulations in Table 1 are expressed in parts by mass. The physical properties of the photocurable resin compositions obtained in each example or their cured products were measured using the following methods. The measurement results are shown in Table 1.

[0101] <Measurement of absorbance at 405 nm> Using the photocurable resin composition of each example, the absorbance A at a wavelength of 405 nm was measured according to the following <Measurement method>. ４０５ was measured.

[0102] <Measurement Method> The photocurable resin composition and isopropanol (manufactured by Tokyo Chemical Industry Co., Ltd., product name: Isopropyl Alcohol) were mixed at a mass ratio of photocurable resin composition:isopropanol = 7:93, and a sample was prepared by dissolving the photocurable resin composition in isopropanol. The sample was then placed in a sample cell with an optical path length of 10 mm (material: ES quartz glass, optical path length 10 mm, optical path width 10 mm, type: two-sided transparent, product name: standard quartz cell for spectrophotometer (two-sided transparent)). According to the <Absorbance Measurement Conditions> below, the absorbance was measured at a wavelength of 405 nm and an incident light intensity I ０ The light intensity I of the light transmitted through the sample cell was measured. Then, the absorbance A at a wavelength of 405 nm was calculated using the following equation (4). ４０５ was calculated. (4): A ４０５ = -log １０ (I / I ０ )

[0103] <Absorbance measurement conditions> Measurement device: ultraviolet-visible-near-infrared spectrophotometer (manufactured by JASCO Corporation, product name: V770) Measurement method: transmission method Measurement wavelength: 405 nm Reference: isopropanol (manufactured by Tokyo Chemical Industry Co., Ltd., product name: Isopropyl Alcohol) Detector: photomultiplier tube, cooled PbS photoconductive element

[0104] <Evaluation of Surface Unevenness> Using the photocurable resin composition of each example, an optical molded body was produced according to the following <Production Conditions for Optical Molded Body>. The produced optical molded body was evaluated for surface unevenness according to the following <Evaluation Method>.

[0105] <Conditions for producing optical molded body> A 2.0 mm thick, 50 mm x 50 mm SUS304 substrate (product name: SUS304-BA, manufactured by Standard Test Piece Co., Ltd.) with one side mirror-finished was placed on top of a 3.0 mm thick, 50 mm x 50 mm silicone sheet (material: silicone rubber, hardness: 50 degrees) with a 35 mm diameter circular hole. After filling the circular hole in the silicone sheet with a photocurable resin composition, a 0.7 mm thick, 50 mm x 50 mm alkali-free glass (product name: JIS R 3202 glass plate thread surface, manufactured by Test Piece Co., Ltd.) was further placed on top. At this time, it was confirmed that no air bubbles were present. Hereinafter, the product obtained by placing a silicone sheet on the above-mentioned SUS304 substrate, filling the circular hole in the silicone sheet with a photocurable resin, and then further placing alkali-free glass on top of that may be referred to as a laminate. The obtained laminate was placed on a SUS lab jack and the height was adjusted. Using an LED light irradiation device (manufactured by CCS, product name: 405 nm-120 mm air-cooled batch-type irradiation device, model number: HLDL-120505-NWPSC), the photocurable resin composition was irradiated with LED light having a wavelength of 405 nm at 110 mW for 1 minute from above the alkali-free glass. 30 seconds after irradiation with the LED light, the laminate was irradiated with LED light having a wavelength of 405 nm at 810 mW for 2 minutes. After irradiating with the LED light, the laminate was allowed to cool at 23 ° C for 30 minutes. After cooling, the cured product of the photocurable resin composition was released from the SUS304 substrate, silicone sheet, and alkali-free glass to obtain an optical molded body. The illuminance of the LED light was measured using a 405 nm illuminance meter (manufactured by USHIO, product name: UIT150).

[0106] <Evaluation Method> A 2 mm thick, 100 mm x 100 mm alkali-free glass (manufactured by Test Piece Co., Ltd., JIS R 3202 (glass plate) thread side) was placed on white paper (manufactured by Tanomeeru Co., Ltd., TANOSEE PPC Paper Type FW A4 PPCFW-A4). Furthermore, the prepared optical molded body was placed on the alkali-free glass. In this state, the optical molded body was observed under irradiation with a white LED having an irradiation intensity of 300 lux or more and 500 lux or less. Specifically, the pattern projected on the white paper due to the surface unevenness of the optical molded body was observed. The proportion of the pattern projected on the white paper due to the surface unevenness of the optical molded body to the surface of the optical molded body that was in contact with the SUS304 substrate was defined as the proportion R. The case where the ratio R was 0% or more and less than 2% was rated as A, the case where it was 2% or more and less than 20% was rated as B, and the case where it was 20% or more and 100% or less was rated as C.

[0107]

[0108] This application claims priority based on Japanese Patent Application No. 2024-012816, filed January 31, 2024, the disclosure of which is incorporated herein by reference in its entirety.

Claims

1. A photocurable resin composition that can be used for an optical molded body, wherein the photocurable resin composition has an absorbance A at a wavelength of 405 nm measured according to the following <Measurement Method>. ４０５ A sample was prepared by dissolving the photocurable resin composition in isopropanol at a mass ratio of 7:

93. The sample was then placed in a sample cell with an optical path length of 10 mm, and the incident light intensity I ０ When light having a wavelength of 405 nm is incident on the sample cell, the transmitted light intensity I of the light transmitted through the sample cell is measured, and the absorbance A at a wavelength of 405 nm is calculated by the following formula (1). ４０５ Calculate (1): A ４０５ = -log １０ (I / I ０ ) 2. The absorbance A ４０５ The photocurable resin composition according to claim 1, wherein the ρ is 0.010 or more.

3. The photocurable resin composition according to claim 1 or 2, which contains a (meth)acrylate monomer.

4. The photocurable resin composition according to claim 3, wherein the (meth)acrylate monomer comprises one or more selected from the group consisting of monofunctional (meth)acrylate monomers and difunctional or higher functional (meth)acrylate monomers.

5. The photocurable resin composition according to claim 3 or 4, wherein the (meth)acrylate monomer includes a (meth)acrylate monomer having an alicyclic skeleton.

6. The photocurable resin composition according to claim 5, wherein the (meth)acrylate monomer having an alicyclic skeleton contains one or more skeletons selected from the group consisting of an adamantane skeleton, a norbornane skeleton, and a dicyclopentadiene skeleton.

7. The photocurable resin composition according to claim 5 or 6, wherein the content of the (meth)acrylate monomer having an alicyclic skeleton is 30 parts by mass or more and 100 parts by mass or less, when the total content of the (meth)acrylate monomers is 100 parts by mass.

8. The photocurable resin composition according to any one of claims 3 to 7, wherein the (meth)acrylate monomer comprises a (meth)acrylate monomer having a linear hydrocarbon skeleton.

9. The photocurable resin composition according to any one of claims 1 to 8, further comprising a photopolymerization initiator.

10. The photocurable resin composition according to claim 9, wherein the photopolymerization initiator comprises a photoradical polymerization initiator.

11. A photocurable resin composition according to claim 9 or 10, wherein the content of the photopolymerization initiator is 0.10 parts by mass or more and 10 parts by mass or less, when the total content of the (meth)acrylate monomers is 100 parts by mass.

12. The photocurable resin composition according to any one of claims 1 to 11, further comprising an antioxidant.

13. The photocurable resin composition according to claim 12, wherein the content of the antioxidant is 0.010 parts by mass or more and 10 parts by mass or less, when the total content of the (meth)acrylate monomers is 100 parts by mass.

14. The photocurable resin composition according to any one of claims 1 to 13, further comprising a light stabilizer.

15. A photocurable resin composition according to claim 14, wherein the content of the light stabilizer is 0.010 parts by mass or more and 5 parts by mass or less, when the total content of the (meth)acrylate monomers is 100 parts by mass.

16. A photocurable resin composition according to any one of claims 1 to 15, wherein the content of the (meth)acrylate monomer is 80% by mass or more but less than 100% by mass, when the entire photocurable resin composition is taken as 100% by mass.

17. A photocurable resin composition according to any one of claims 1 to 16, which can be used in a casting method.

18. An optical molded body comprising a cured product of the photocurable resin composition according to any one of claims 1 to 17.

19. The optical molded body of claim 18, wherein the optical molded body comprises a lens.

20. The optical molded body according to claim 19, wherein the lens comprises one or more lenses selected from a lens for a virtual reality device (VR lens), a lens for a mixed reality device (MR lens), a lens for an augmented reality device (AR lens), a lens for a cross reality device (xR lens), and a lens for a head-mounted display (HMD lens).

21. The optical molded body according to any one of claims 18 to 20, wherein the maximum thickness is 20.0 mm or less.

22. The optical molded body according to any one of claims 18 to 21, wherein the maximum thickness of the optical molded body is 1.0 mm or more.

23. An optical device comprising the optical molded body according to any one of claims 18 to 22.

24. A method for producing an optical molded body, comprising: a thickening step of increasing the viscosity of a photocurable resin composition by irradiating the photocurable resin composition with light using an irradiation device having a light source peak at a wavelength of 360 nm or more and 410 nm or less; and a curing step of curing the photocurable resin composition by irradiating the photocurable resin composition with light using an irradiation device having a light source peak at a wavelength of 360 nm or more and 410 nm or less after the thickening step.

25. The method for producing an optical molded body according to claim 24, further comprising an upper mold setting step of setting an upper mold for molding on the photocurable resin composition after the thickening step and before the curing step.

26. The method for producing an optical molded body according to claim 24 or 25, further comprising a coating step of coating the photocurable resin composition onto a lower mold for molding, wherein the thickening step is carried out after the coating step.

27. A method for producing an optical molded body according to any one of claims 24 to 26, wherein the thickening step includes a step of irradiating the photocurable resin composition with light at an irradiation intensity of 90 mW or more and 130 mW or less using an irradiation device having a light source peak at a wavelength of 360 nm or more and 410 nm or less.

28. A method for producing an optical molded body according to any one of claims 24 to 27, wherein the thickening step includes a step of irradiating the photocurable resin composition with light for an irradiation time of 1 second to 300 seconds using an irradiation device having a light source peak at a wavelength of 360 nm to 410 nm.

29. A method for producing an optical molded body according to any one of claims 24 to 28, wherein the thickening step includes a step of irradiating the photocurable resin composition with light at an integrated light intensity of 50 mJ or more and 20.0 J or less using an irradiation device having a light source peak at a wavelength of 360 nm or more and 410 nm or less.

30. A method for producing an optical molded body according to any one of claims 24 to 29, wherein in the thickening step, the thickness of the photocurable resin composition is 15.0 mm or less.

31. A method for producing an optical molded body according to any one of claims 24 to 30, wherein the photocurable resin composition comprises the photocurable resin composition according to any one of claims 1 to 17.

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