Photocurable resin composition, cured product, optical molded body, and optical device

Abstract

A photocurable resin composition which can be used for an optical molded body, the photocurable resin composition comprising a (meth)acrylate monomer of 2 or more functions, the (meth)acrylate monomer of 2 or more functions comprising one or two or more selected from the group consisting of an alicyclic 2-functional (meth)acrylate monomer and a linear 2-functional (meth)acrylate monomer, the total content of the alicyclic 2-functional (meth)acrylate monomer and the linear 2-functional (meth)acrylate monomer being 60 mass% or more and 100 mass% or less when the total content of the (meth)acrylate monomer of 2 or more functions is 100 mass%.

Description

Technical Field

[0001] This invention relates to photocurable resin compositions, cured products, optical molded articles, and optical devices. Background Technology

[0002] In recent years, thermoplastic resins and UV-curable resin compositions have been studied in optical system lenses from the viewpoint of heat resistance and low birefringence. Among these, methacrylic acid-based resin compositions are being investigated as thermoplastic resins. For example, the techniques described in Patent Document 1 and Patent Document 2 can be cited as techniques for methacrylic acid-based resin compositions.

[0003] Patent Document 1 describes a methacrylic resin composition with high heat resistance, highly controlled birefringence, high transmittance over a long optical path, and excellent hue and transparency. The composition comprises a methacrylic resin whose main chain contains at least a structural unit derived from an N-substituted maleimide monomer, has a glass transition temperature exceeding 120°C and below 160°C, a resin temperature of 270°C, and a shear rate of 1000 sec. -1 Under these conditions, the melt viscosity is below 250 Pa·s, and the absolute value of the photoelastic modulus is 1 × 10⁻⁶. -12 pa -1 The transmittance of the solution prepared by dissolving the resin composition in chloroform at a mass-volume percentage of 20% was measured to be 94% or more under conditions of an optical path length of 100 mm and a wavelength of 470 nm, and the transmittance was measured to be 96% or more under conditions of a wavelength of 700 nm.

[0004] Patent Document 2 describes a photocurable composition with the aim of providing a photocurable composition that is fast-curing, non-anaerobic, low-viscosity, low-odor, and has excellent storage stability, and in particular, a photocurable composition that produces a colorless and transparent product with excellent properties required for lenses, such as low optical strain, heat resistance, low water absorption, toughness, and high hardness. The photocurable composition is characterized by containing tricyclodecane skeleton di(meth)acrylate (A), a trifunctional or quadrifunctional secondary thiol (B), a pyrolysis photopolymerization initiator (C), and a hindered phenolic antioxidant (D). The photocurable composition does not contain primary thiol, and the content ratio (by weight) of components (A), (B), (C), and (D) is within the following range.

[0005] Ingredient (A) / Ingredient (B) = 75 / 25 ~ 95 / 5

[0006] Component (C): 2 to 10 parts by weight relative to 100 parts by weight of components (A) and (B) combined.

[0007] Component (D): 0.1 to 1 part by weight relative to 100 parts by weight of components (A) and (B) combined.

[0008] Existing technical documents

[0009] Patent documents

[0010] Patent Document 1: Japanese Patent Application Publication No. 2019-35015

[0011] Patent Document 2: Japanese Patent Application Publication No. 2022-32186 Summary of the Invention

[0012] The problem that the invention aims to solve

[0013] The present invention provides a photocurable resin composition capable of reducing in-plane phase difference of optically molded objects.

[0014] Methods for solving problems

[0015] To achieve the aforementioned objective, the inventors conducted repeated and in-depth research. Their findings revealed a correlation between the types of difunctional (meth)acrylate monomers contained in the photocurable resin composition and the in-plane phase difference Re of the resulting optically molded article. Based on this understanding, the inventors further conducted repeated and in-depth research, and discovered that by using a photocurable resin composition with a total content of difunctional (meth)acrylate monomers of 100 parts by mass, the total content of alicyclic difunctional (meth)acrylate monomers and linear difunctional (meth)acrylate monomers is 60 parts by mass or more and 100 parts by mass or less, thus completing the present invention. [1]

[0017] A photocurable resin composition is provided, which is a photocurable resin composition that can be used for optical molding. The photocurable resin composition comprises a (meth)acrylate monomer with two or more functionalities. The (meth)acrylate monomer with two or more functionalities comprises one or more selected from the group consisting of alicyclic (meth)acrylate monomers and linear (meth)acrylate monomers. When the total content of the (meth)acrylate monomers with two or more functionalities is set to 100 parts by mass, the total content of the alicyclic (meth)acrylate monomers and the linear (meth)acrylate monomers is 60 parts by mass or more and 100 parts by mass or less. [2]

[0019] According to the photocurable resin composition described above [1], it comprises one or more selected from the group consisting of monofunctional (meth)acrylate monomers and (meth)acrylate monomers with more than two functions, wherein when the total content of the monofunctional (meth)acrylate monomers and the (meth)acrylate monomers with more than two functions is set to 100 parts by mass, the content of the (meth)acrylate monomers with more than two functions is 5.0 parts by mass or more and 90 parts by mass or less. [3]

[0021] The photocurable resin composition according to [2] above contains the above-mentioned monofunctional (meth)acrylate monomer. [4]

[0023] According to the photocurable resin composition described in [2] or [3] above, wherein the monofunctional (meth)acrylate monomer has an alicyclic skeleton. [5]

[0025] According to any one of the above-mentioned photocurable resin compositions [1] to [4], the in-plane phase difference Re of the cured film prepared using the above-mentioned photocurable resin composition according to the following <curing film preparation conditions> is 50.0 nm or less, as measured according to the following <determination of in-plane phase difference Re>.

[0026] <Conditions for Curing Film Production>

[0027] A 3mm thick, 50mm x 50mm silicone sheet (material: silicone rubber, hardness: 50 degrees) with a 35mm φ circular hole is placed on a 0.7mm thick, 50mm x 50mm alkali-free glass. The aforementioned photocurable resin composition is filled into the circular hole. Then, a 0.7mm thick, 50mm x 50mm alkali-free glass is placed on top of the alkali-free glass. The glass is placed on an SUS laboratory lift platform and the height is adjusted. The photocurable resin composition is irradiated with 405nm LED light at 810mW for 3 minutes from above the alkali-free glass. The glass is then flipped over and irradiated with 405nm LED light at 810mW for 3 minutes. After natural cooling at 23°C for 30 minutes, the cured photocurable resin composition is demolded from the alkali-free glass and the silicone sheet to obtain a cured film of the photocurable resin composition.

[0028] <Determination of in-plane phase difference Re>

[0029] For the above-mentioned cured film, one hour after the LED light irradiation is completed, the in-plane phase difference Re at a distance of 10.0 mm from the center of the above-mentioned cured film is measured using a two-dimensional birefringence evaluation device at an ambient temperature of 23°C and under atmospheric conditions. [6]

[0031] According to any one of the above-mentioned photocurable resin compositions [1] to [5], the in-plane phase difference Re after heating, as measured by the following <determination of in-plane phase difference Re after heating, is 16.0 nm or less after the curing film prepared using the above-mentioned photocurable resin composition according to the following <curing film preparation conditions> is subjected to the following <heat treatment>.

[0032] <Conditions for Curing Film Production>

[0033] A 3mm thick, 50mm x 50mm silicone sheet (material: silicone rubber, hardness: 50 degrees) with a 35mm φ circular hole is placed on a 0.7mm thick, 50mm x 50mm alkali-free glass. The aforementioned photocurable resin composition is filled into the circular hole. Then, a 0.7mm thick, 50mm x 50mm alkali-free glass is placed on top of the alkali-free glass. The glass is placed on an SUS laboratory lift platform and the height is adjusted. The photocurable resin composition is irradiated with 405nm LED light at 810mW for 3 minutes from above the alkali-free glass. The glass is then flipped over and irradiated with 405nm LED light at 810mW for 3 minutes. After natural cooling at 23°C for 30 minutes, the cured photocurable resin composition is demolded from the alkali-free glass and the silicone sheet to obtain a cured film of the photocurable resin composition.

[0034] <Heat Treatment>

[0035] The cured film was heated from 23°C to 120°C at a constant rate over 1 hour, heated at 120°C for 1 hour, cooled from 120°C to 23°C at a constant rate over 3 hours, and then exothermized at 23°C for 3 hours.

[0036] <Determination of in-plane phase difference Re after heat treatment>

[0037] For the cured film, one hour after the completion of the above-mentioned heat treatment, the in-plane phase difference Re at a distance of 10.0 mm from the center of the cured film is measured using a two-dimensional birefringence evaluation device at an ambient temperature of 23°C and under atmospheric conditions. [7]

[0039] The photocurable resin composition according to any one of [1] to [6] above further comprises an antioxidant. [8]

[0041] The photocurable resin composition according to any one of [1] to [7] above further comprises a photopolymerization initiator. [9]

[0043] According to the photocurable resin composition described above [8], wherein the photopolymerization initiator comprises a photoradical polymerization initiator.

[10]

[0045] The photocurable resin composition according to any one of [1] to [9] above further comprises a light stabilizer.

[11]

[0047] The photocurable resin composition according to any one of [1] to

[10] above can be used in casting.

[12]

[0049] The photocurable resin composition according to any one of [1] to

[11] above can be used 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 extended reality devices (xR lenses), and lenses for head-mounted displays (HMD lenses).

[13]

[0051] The cured product of the photocurable resin composition described in any one of [1] to

[12] above.

[14]

[0053] An optically molded body comprising a cured product of the photocurable resin composition described in any one of [1] to

[12] above.

[15]

[0055] The optical molding body described above

[14] includes a lens.

[16]

[0057] According to the optical shaping body described above

[15] , the lens includes one or more of the following: a lens for virtual reality devices (VR lens), a lens for mixed reality devices (MR lens), a lens for augmented reality devices (AR lens), a lens for extended reality devices (xR lens), and a lens for head-mounted displays (HMD lens).

[17]

[0059] The optical molding body according to any one of

[14] to

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

[18]

[0061] The optical molding body according to any one of

[14] to

[17] above, wherein the maximum thickness portion is 1.0 mm or more.

[19]

[0063] An optical device comprising the optical molding body described in any one of

[14] to

[18] above.

[0064] Invention Effects

[0065] According to the present invention, a photocurable resin composition capable of reducing in-plane phase difference of an optically molded body can be provided. Detailed Implementation

[0066] The term "(meth)acrylate" in this specification includes both acrylate and methacrylate. The same applies to terms such as "(meth)acryloyl" and similar expressions.

[0067] For each component in this embodiment, one type can be used, or two or more types can be used in combination. In addition, the "~" symbol indicating the numerical range means above and below, including both the upper and lower limits.

[0068] (Photocurable resin composition)

[0069] The photocurable resin composition of this embodiment (hereinafter also appropriately referred to as "resin composition") is a photocurable resin composition that can be used in optically molded articles. It contains a (meth)acrylate monomer (A2) with two or more functions. The (meth)acrylate monomer (A2) with two or more functions includes one or more selected from the group consisting of alicyclic difunctional (meth)acrylate monomers and linear difunctional (meth)acrylate monomers. When the total content of the (meth)acrylate monomer (A2) with two or more functions is set to 100 parts by mass, the total content of the alicyclic difunctional (meth)acrylate monomer and the linear difunctional (meth)acrylate monomer is 60 parts by mass or more and 100 parts by mass or less.

[0070] The photocurable resin composition of this embodiment, by having the structure described above, is able to reduce the in-plane phase difference of the optically molded body.

[0071] The photocurable resin composition contains a polymerizable compound. From the viewpoint of reducing coloration of the optically molded body, the polymerizable compound contains a (meth)acrylate monomer (A2) with two or more functional groups. The (meth)acrylate monomer (A2) with two or more functional groups contains one or more selected from the group consisting of alicyclic difunctional (meth)acrylate monomers and linear difunctional (meth)acrylate monomers.

[0072] The properties of the photocurable resin composition are not particularly limited. However, from the viewpoint of being suitable for forming optically molded articles by injection molding or casting molding, the photocurable resin composition is preferably in liquid form.

[0073] Furthermore, from the viewpoint of increasing the design freedom of optically molded bodies, photocurable resin compositions are preferably used for molding using casting methods.

[0074] Next, specific examples will be given to illustrate the composition of the photocurable resin composition.

[0075] It should be noted that the photocurable resin composition may consist of a polymeric compound or contain components other than polymeric compounds. Specific examples of other components may include one or more selected from the group consisting of antioxidants (B), photopolymerization initiators (C), and light stabilizers (D) as described below.

[0076] From the viewpoint of being able to further reduce the in-plane phase difference of the optically shaped body, the (meth)acrylate monomer (A2) with more than two functions preferably contains a methacrylate monomer with more than two functions.

[0077] From the viewpoint of being able to further reduce the in-plane phase difference of the optically shaped body, the polymerizable compound preferably contains a monofunctional (meth)acrylate monomer (A1), and more preferably contains a monofunctional methacrylate monomer.

[0078] From the viewpoint of further reducing the in-plane phase difference of the optically molded body, when the total content of monofunctional (meth)acrylate monomer (A1) and difunctional or more (meth)acrylate monomer (A2) is set to 100 parts by mass, the content of difunctional or more (meth)acrylate monomer (A2) in the photocurable resin composition of this embodiment is preferably 5.0 parts by mass or more and 90 parts by mass or less, more preferably 10 parts by mass or more and 70 parts by mass or less, even more preferably 12 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 18 parts by mass or more and 35 parts by mass or less.

[0079] From the viewpoint of further reducing the in-plane phase difference of the optically molded body, the mass ratio of the content of monofunctional (meth)acrylate monomer (A1) in the photocurable resin composition of this embodiment to the content of difunctional or more (meth)acrylate monomer (A2) is preferably 0.50 or more and 10.0 or less, more preferably 1.00 or more and 8.00 or less, even more preferably 1.50 or more and 6.00 or less, even more preferably 1.80 or more and 5.00 or less, and even more preferably 2.00 or more and 4.50 or less.

[0080] From the viewpoint of further reducing the in-plane phase difference of the optically molded body, when the total content of (meth)acrylate monomer (A) is set to 100 parts by mass, the total content of (meth)acrylate monomer (A) other than the (meth)acrylate monomer (A) having an aromatic ring in the photocurable resin composition of this embodiment is preferably 60 parts by mass or more and 100 parts by mass or less, more preferably 70 parts by mass or more and 100 parts by mass or less, even more preferably 80 parts by mass or more and 100 parts by mass or less, even more preferably 85 parts by mass or more and 100 parts by mass or less, even more preferably 90 parts by mass or more and 100 parts by mass or less, and even more preferably 95 parts by mass or more and 100 parts by mass or less.

[0081] From the viewpoint of further reducing the in-plane phase difference of the optically molded body, when the total content of (meth)acrylate monomer (A) is set to 100 parts by mass, the total content of (meth)acrylate monomer (A) other than the branched (meth)acrylate monomer (A) in the photocurable resin composition of this embodiment is preferably 60 parts by mass or more and 100 parts by mass or less, more preferably 70 parts by mass or more and 100 parts by mass or less, even more preferably 80 parts by mass or more and 100 parts by mass or less, even more preferably 85 parts by mass or more and 100 parts by mass or less, even more preferably 90 parts by mass or more and 100 parts by mass or less, and even more preferably 95 parts by mass or more and 100 parts by mass or less.

[0082] From the viewpoint of further reducing the in-plane phase difference of the optically molded body, when the total content of (meth)acrylate monomer (A) is set to 100 parts by mass, the total content of monofunctional (meth)acrylate monomer (A1) other than aromatic ring monofunctional (meth)acrylate monomer in the photocurable resin composition of this embodiment is preferably 10 parts by mass or more and 100 parts by mass or less, more preferably 30 parts by mass or more and 95 parts by mass or less, even more preferably 40 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, and even more preferably 60 parts by mass or more and 90 parts by mass or less.

[0083] <Monofunctional (meth)acrylate monomer (A1)>

[0084] Monofunctional (meth)acrylate monomers (A1) include, for example, one or more of the following groups: aromatic ring monofunctional (meth)acrylates; alicyclic monofunctional (meth)acrylates; linear monofunctional (meth)acrylates (e.g., monofunctional (meth)acrylate monomers having a linear hydrocarbon skeleton); branched monofunctional (meth)acrylates; and chain monofunctional (meth)acrylates.

[0085] The monofunctional (meth)acrylate monomer (A1) preferably comprises selected from isobornyl (meth)acrylate, dicyclopentyl (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.), dicyclopentenoxyethyl (meth)acrylate, tetrahydrofurfuryl (meth)acrylate, 2-hydroxyethyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate, isobutyl (meth)acrylate, tert-butyl (meth)acrylate, isooctyl (meth)acrylate, 2-methoxyethyl (meth)acrylate, and methoxytriethylene glycol. (Meth)acrylate, 2-ethoxyethyl (meth)acrylate, 3-methoxybutyl (meth)acrylate, ethoxyethyl (meth)acrylate, butoxyethyl (meth)acrylate, ethoxydiethylene glycol (meth)acrylate, methoxydihexyl ethyl (meth)acrylate, ethyl diethylene glycol (meth)acrylate, cyclic trimethylolpropane methyl acetal mono(meth)acrylate, imide (meth)acrylate, isoamyl (meth)acrylate, ethoxylated succinic acid (meth)acrylate, trifluoroethyl (meth)acrylate, ω-carboxylated polycaprolactone mono(meth)acrylate, cyclohexyl (meth)acrylate, 2-(2-ethoxyethoxy)ethyl (meth)acrylate, stearate (meth)acrylate, (meth)acrylate Isostearyl acrylate (e.g., S-1800A, manufactured by Shin-Nakamura Chemical Industry Co., Ltd.), diethylene glycol monobutyl ether (meth)acrylate, lauryl acrylate (e.g., LA, manufactured by Osaka Organic Chemical Industry Co., Ltd.), isodecyl acrylate (meth)acrylate, octyl / decyl acrylate (meth)acrylate, tridecyl acrylate (meth)acrylate, caprolactone (meth)acrylate, ethoxylated (4)nonylphenol (meth)acrylate, methoxy polyethylene glycol (350) mono(meth)acrylate, methoxy polyethylene glycol (550) mono(meth)acrylate, phenoxyethyl acrylate (meth)acrylate, benzyl acrylate (meth)acrylate, methylphenoxyethyl acrylate (meth)acrylate, caprolactone-modified tetrahydrofurfuryl acrylate (meth)acrylate, (meth)propyl The group consisting of one or more of the following: tribromophenyl acrylate, ethoxylated tribromophenyl acrylate, 2-phenoxyethyl acrylate, ethylene oxide adduct of 2-phenoxyethyl acrylate, propylene oxide adduct of 2-phenoxyethyl acrylate, phenoxydiethylene glycol (meth)acrylate, 2-hydroxy-3-phenoxypropyl acrylate, 3-methacryloyloxymethylcyclohexene oxide, 3-(methacryloyloxymethylcyclohexene oxide), ethoxylated o-phenylphenol (meth)acrylate (e.g., A-LEN-10, manufactured by Shin-Nakamura Chemical Industry Co., Ltd.), 2-methacryloyloxy-2-methyladamantane, and 2-methacryloyloxy-2-ethyladamantane.

[0086] From the viewpoint of being able to further reduce the in-plane phase difference of the optically shaped body, the monofunctional (meth)acrylate monomer (A1) is more preferably one or more selected from the group consisting of lauryl (meth)acrylate and dicyclopentyl (meth)acrylate.

[0087] From the viewpoint of further reducing the in-plane phase difference of the optically molded article, the monofunctional (meth)acrylate monomer (A1) preferably has an alicyclic backbone. From the viewpoint of further reducing the in-plane phase difference of the optically molded article, the monofunctional (meth)acrylate monomer (A1) more preferably contains dicyclopentyl (meth)acrylate, and even more preferably contains dicyclopentyl methacrylate.

[0088] <2 or more functional (meth)acrylate monomers (A2)>

[0089] From the viewpoint of reducing in-plane phase difference in optically molded articles, the (meth)acrylate monomer (A2) with more than two functions comprises one or more selected from the group consisting of alicyclic difunctional (meth)acrylate monomers and linear difunctional (meth)acrylate monomers. From the viewpoint of further reducing in-plane phase difference in optically molded articles, the methacrylate monomer (A2) with more than two functions preferably comprises one or more selected from the group consisting of alicyclic difunctional methacrylate monomers and linear difunctional methacrylate monomers.

[0090] From the viewpoint of reducing the in-plane phase difference of the optically molded body, when the total content of the (meth)acrylate monomer (A2) with two or more functions is set to 100 parts by mass, the total content of the alicyclic difunctional (meth)acrylate monomer and the linear difunctional (meth)acrylate monomer in the photocurable resin composition of this embodiment is 60 parts by mass or more and 100 parts by mass or less, preferably 70 parts by mass or more and 100 parts by mass or less, more preferably 80 parts by mass or more and 100 parts by mass or less, even more preferably 85 parts by mass or more and 100 parts by mass or less, even more preferably 90 parts by mass or more and 100 parts by mass or less, and even more preferably 95 parts by mass or more and 100 parts by mass or less.

[0091] Alicyclic difunctional (meth)acrylate monomers are difunctional (meth)acrylate monomers with an alicyclic hydrocarbon structure in their 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.

[0092] Alicyclic hydrocarbon structures can be either saturated or unsaturated. From the perspective of improving heat resistance, saturated hydrocarbon structures are preferred for alicyclic hydrocarbon structures.

[0093] Furthermore, the alicyclic hydrocarbon structure can be a monocyclic hydrocarbon structure, a fused-ring hydrocarbon structure, or a bridged-ring hydrocarbon structure. Alicyclic difunctional (meth)acrylate monomers can contain groups with these alicyclic hydrocarbon structures in their molecular structure, preferably containing divalent groups with alicyclic hydrocarbon structures.

[0094] Specific examples of monocyclic hydrocarbon groups include groups with cyclohexylene and cyclohexyl groups that have cycloalkane structures; and groups with cyclodectrienyl and cyclodectrienyl groups that have cycloolefin skeletons.

[0095] Specific examples of polycyclic hydrocarbon groups include tricyclodecanediyl, dicyclopentyl, and dicyclopentenyl groups that have a dicyclopentadiene skeleton; norbornanediyl, isobornanediyl, norbornyl, and isobornyl groups that have a norbornane skeleton; and adamantanediyl and adamantanealkyl groups that have an adamantane skeleton.

[0096] From the viewpoint of further reducing the coloring of optically molded parts, the cyclic hydrocarbon group in the alicyclic difunctional (meth)acrylate monomer is preferably a group having a dicyclopentadiene backbone.

[0097] Furthermore, from the viewpoint of reducing curing shrinkage during the molding of optically molded articles, the alicyclic difunctional (meth)acrylate monomer preferably includes tricyclodecanediethanol di(meth)acrylate, more preferably tricyclodecanediethanol di(meth)acrylate, and even more preferably tricyclodecanediethanol dimethacrylate (e.g., DCP, manufactured by Shin-Nakamura Chemical Industry Co., Ltd.).

[0098] Linear difunctional (meth)acrylate monomers are (meth)acrylates that have a linear structure in their molecular structure and have two (meth)acryloyl groups.

[0099] From the viewpoint of improving crack resistance during the molding of optical molded articles, the linear structure preferably includes divalent linear hydrocarbon groups. From the viewpoint of reducing liquid volume deviations caused by monomer volatilization during the molding of optical molded articles, the number of carbon atoms in the divalent linear hydrocarbon groups is, for example, 1 or more, preferably 2 or more, and more preferably 4 or more. Furthermore, from the viewpoint of improving heat resistance, the number of carbon atoms in the divalent linear hydrocarbon groups is preferably 20 or less, and more preferably 14 or less.

[0100] As a specific example of a linear difunctional (meth)acrylate monomer, di(meth)acrylate of an alkanediol can be cited.

[0101] The linear difunctional (meth)acrylate monomer preferably comprises selected from 1,6-hexanediol di(meth)acrylate (e.g., A-HD-N, manufactured by Shin-Nakamura Chemical Industry Co., Ltd.; HD-N, manufactured by Shin-Nakamura Chemical Industry Co., Ltd.), 1,9-nonanediol di(meth)acrylate (e.g., A-NOD-N, manufactured by Shin-Nakamura Chemical Industry Co., Ltd.; LIGHT ACRYLATE 1,9 ND-A, manufactured by Kyoeisha Chemical Co., Ltd.; NO ... LIGHT ACRYLATE 1,9 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 Industry Co., Ltd.; DOD-N, manufactured by Shin-Nakamura Chemical Industry Co., Ltd.), 1,12-dodecanediol di(meth)acrylate (e.g., DDD, manufactured by Shin-Nakamura Chemical Industry Co., Ltd.; SR262, manufactured by Arkema), ethylene glycol di(meth)acrylate (e.g., SR206NS, manufactured by Arkema), triethylene glycol di(meth)acrylate (e.g., SR272, manufactured by Arkema), polyethylene glycol di(meth)acrylate (e.g., A-400, manufactured by Shin-Nakamura Chemical Industry Co., Ltd.), 1,3-butanediol di(meth)acrylate (e.g., BG, manufactured by Shin-Nakamura Chemical Industry Co., Ltd.), and 1,4-butanediol di(meth)acrylate (e.g., BD, manufactured by Shin-Nakamura Chemical Industry Co., Ltd.) are one or more of the following:

[0102] From the viewpoint of reducing cracks generated in optically molded articles, linear difunctional (meth)acrylate monomers more preferably include one or more (meth)acrylates selected from the group consisting of 1,12-dodecanediol di(meth)acrylate and 1,9-nonanediol di(meth)acrylate.

[0103] From the viewpoint of further reducing the coloring of optically molded articles, the (meth)acrylate monomer (A2) with two or more functionalities preferably has an alicyclic backbone. From the viewpoint of further reducing the coloring of optically molded articles, the (meth)acrylate monomer (A2) with two or more functionalities more preferably contains tricyclodecanediethanol di(meth)acrylate, and even more preferably contains tricyclodecanediethanol dimethacrylate.

[0104] From the viewpoint of further reducing the coloring of optically molded articles, the (meth)acrylate monomer (A2) with more than two functionalities preferably has a straight-chain hydrocarbon backbone. From the viewpoint of further reducing the coloring of optically molded articles, the (meth)acrylate monomer (A2) with more than two functionalities more preferably contains 1,12-dodecanediol di(meth)acrylate, and even more preferably contains 1,12-dodecanediol dimethacrylate.

[0105] It should be noted that the (meth)acrylate monomer (A2) with more than two functions may include (meth)acrylate monomers (A2) with more than two functions other than linear (meth)acrylate monomers and alicyclic (meth)acrylate monomers. For example, the (meth)acrylate monomer (A2) with more than two functions may include (meth)acrylate monomers with more than three functions.

[0106] The (meth)acrylate monomer (A2) with more than two functionalities may, for example, comprise one or more selected from the group consisting of (meth)acrylate monomers (A2) with more than two functionalities having an aromatic ring and (meth)acrylate monomers (A2) with more than two branched chains. Furthermore, the (meth)acrylate monomer (A2) with more than two functionalities may, for example, comprise one or more selected from the group consisting of (meth)acrylate monomers with a difunctional aromatic ring and (meth)acrylate monomers with two branched chains. The (meth)acrylate monomer with a difunctional aromatic ring is a (meth)acrylate having an aromatic ring in its molecular structure and having two (meth)acryloyl groups. The (meth)acrylate monomer with two branched chains is a (meth)acrylate having a branched structure in its molecular structure and having two (meth)acryloyl groups.

[0107] From the viewpoint of further reducing the in-plane phase difference of the optically molded body, when the total content of the (meth)acrylate monomer (A2) with two or more functions is set to 100 parts by mass, the total content of the (meth)acrylate monomer (A2) with two or more functions other than the (meth)acrylate monomer (A2) with an aromatic ring in the photocurable resin composition of this embodiment is preferably 60 parts by mass or more and 100 parts by mass or less, more preferably 70 parts by mass or more and 100 parts by mass or less, even more preferably 80 parts by mass or more and 100 parts by mass or less, even more preferably 85 parts by mass or more and 100 parts by mass or less, even more preferably 90 parts by mass or more and 100 parts by mass or less, and even more preferably 95 parts by mass or more and 100 parts by mass or less.

[0108] From the viewpoint of further reducing the in-plane phase difference of the optically molded body, when the total content of the (meth)acrylate monomer (A2) with two or more functions is set to 100 parts by mass, the total content of the (meth)acrylate monomer (A2) with two or more functions other than the branched (meth)acrylate monomer (A2) in the photocurable resin composition of this embodiment is preferably 60 parts by mass or more and 100 parts by mass or less, more preferably 70 parts by mass or more and 100 parts by mass or less, even more preferably 80 parts by mass or more and 100 parts by mass or less, even more preferably 85 parts by mass or more and 100 parts by mass or less, even more preferably 90 parts by mass or more and 100 parts by mass or less, and even more preferably 95 parts by mass or more and 100 parts by mass or less.

[0109] <Antioxidant (B)>

[0110] The photocurable resin composition of this embodiment may further include an antioxidant (B). There are no particular limitations on the antioxidant (B), and known antioxidants may be used. The antioxidant (B) may, for example, include one or more selected from the group consisting of phenolic antioxidants, phosphorus antioxidants, sulfur-based antioxidants, hindered amine antioxidants, and thioether antioxidants.

[0111] Examples of phenolic antioxidants include 2,6-di-tert-butylhydroxytoluene and pentaerythritol tetrakis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate].

[0112] Commercially available phenolic antioxidants include, for example, ADK STAB series products manufactured by ADEKA Co., Ltd., such as AO-20, AO-30, AO-40, AO-50, AO-60 and AO-80.

[0113] Examples of phosphorus-based antioxidants include phosphines such as trialkylphosphine and triarylphosphine, as well as trialkyl phosphites and triaryl phosphites.

[0114] Commercially available phosphorus-based antioxidants include, for example, the ADK STAB series manufactured by ADEKA Co., Ltd., such as PEP-4C, PEP-8, PEP-24G, PEP-36, HP-10, 260, 522A, 329K, 1178, 1500, 135A and 3010.

[0115] Examples of sulfur-based antioxidants include dilaurate 3,3-thiodipropionate, dimyristyl 3,3'-thiodipropionate, distearate 3,3-thiodipropionate, lauryl stearate 3,3-thiodipropionate, pentaerythritol tetra(β-lauryl thiopropionate), and 3,9-bis(2-dodecylthioethyl)-2,4,8,10-tetraoxaspiro[5,5]undecane.

[0116] 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, bis(2,2,6,6-tetramethyl-1-(octoxy)-4-piperidin) sebacate, and bis(1,2,2,6,6-pentamethyl-4-piperidin) sebacate.

[0117] Commercially available hindered amine antioxidants include, for example, AL-72 from the ADK STAB series manufactured by ADEKA Corporation, and hindered amine antioxidants from the TINUVIN series manufactured by BASF, such as 111FDL, 123, 144, 152, 292 and 5100.

[0118] Examples of thioether-based antioxidants include bis(tetranyl) 3,3'-thiodipropionate and bis[3-(dodecylthio)propionate]2,2-bis[[3-(dodecylthio)-1-oxopropoxy]methyl]-1,3-propanediyl ester.

[0119] Commercially available thioether-based antioxidants include, for example, ADK STAB series products manufactured by ADEKA Co., Ltd., such as AO-26, AO-412S, and AO-503A.

[0120] From the viewpoint of reducing the coloration of optically molded parts, antioxidant (B) preferably includes one or more of the group consisting of phenolic antioxidants and thioether antioxidants. From the viewpoint of further reducing the coloration of optically molded parts, antioxidant (B) is more preferably included in the group consisting of one or more of the group consisting of bis[3-(dodecylthio)propionic acid]2,2-bis[[3-(dodecylthio)-1-oxopropoxy]methyl]-1,3-propanediyl ester (e.g., ADK STAB AO-412S, manufactured by ADEKA Co., Ltd.) and pentaerythritol tetra[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate] (e.g., ADK STAB AO-60, manufactured by ADEKA Co., Ltd.).

[0121] From the viewpoint of reducing the coloration of optically molded articles, when the total content of monofunctional (meth)acrylate monomer (A1) and difunctional or more (meth)acrylate monomer (A2) is set to 100 parts by mass, the content of 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.

[0122] From the viewpoint of reducing the coloration of optically molded articles, when the total amount of solid components in the photocurable resin composition (the total amount of components that remain as solid substances when the cured product is made) is set to 100% by mass, the content of 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.

[0123] <Photopolymerization Initiator (C)>

[0124] The photocurable resin composition of this embodiment may further include a photopolymerization initiator (C). There are no particular limitations on the photopolymerization initiator (C), and any known polymerization initiator may be used.

[0125] From the viewpoint of stably forming optically shaped bodies at low temperatures, the photopolymerization initiator (C) preferably comprises a photoradical polymerization initiator. A photoradical polymerization initiator is a compound that generates free radicals by irradiation with ultraviolet or visible light.

[0126] Examples of photoradical polymerization initiators include acylphosphine oxide initiators, oxyphenyl acetate initiators, benzoylformic acid initiators, and hydroxyphenyl ketone initiators.

[0127] Examples of photopolymerization initiators (C) include benzophenone, miconazole, 4,4'-bis(diethylamino)benzophenone, xanthonesone, thioxanthonesone, isopropyl xanthonesone, 2,4-diethylthioxanthonesone, 2-ethylanthraquinone, acetophenone, 2-hydroxy-2-methyl-4'-isopropylphenylacetone, isopropyl benzoin ether, isobutyl benzoin ether, 2,2-diethoxyacetophenone, 2,2-dimethoxy-2-phenylacetophenone, camphorquinone, benzoanthrone, ethyl 4-dimethylaminobenzoate, isoamyl 4-dimethylaminobenzoate, 4,4'-bis(tert-butylperoxycarbonyl)benzophenone, 3,4,4'-tris(tert-butylperoxycarbonyl)benzophenone, and 3,3',4,4'-tetra(tert-butylperoxycarbonyl)benzophenone. 3,3',4,4'-Tetra(tert-hexylperoxycarbonyl)benzophenone, 3,3'-Di(methoxycarbonyl)-4,4'-Di(tert-butylperoxycarbonyl)benzophenone, 3,4'-Di(methoxycarbonyl)-4,3'-Di(tert-butylperoxycarbonyl)benzophenone, 4,4'-Di(methoxycarbonyl)-3,3'-Di(tert-butylperoxycarbonyl)benzophenone, 2-(4'-methoxystyryl)-4,6-bis(trichloromethyl)triazine, 2-(3',4'-dimethoxystyryl)-4,6-bis(trichloromethyl)triazine, 2-(2',4'-dimethoxystyryl)-4,6-bis(trichloromethyl)triazine, 2-(2'-methoxyphenyl) Vinyl)-4,6-bis(trichloromethyl)triazine, 2-(4'-pentoxystyryl)-4,6-bis(trichloromethyl)triazine, 4-[p-N,N-di(ethoxycarbonylmethyl)]-2,6-bis(trichloromethyl)triazine, 1,3-bis(trichloromethyl)-5-(2'-chlorophenyl)triazine, 1,3-bis(trichloromethyl)-5-(4'-methoxyphenyl)triazine, 2-(p-dimethylaminostyryl)benzoxazole, 2-(p-dimethylaminostyryl)benzothiazole, 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'-tetra(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-pyrrolo-1-yl)phenyl)titanium, 1-hydroxycyclohexylphenyl ketone, 2-hydroxy-2-methyl-1-phenyl-1-propanone, 1-[4-(2-hydroxyethoxy)phenyl]-2-hydroxy-2-methyl-1-propanone, 2-hydroxy-1-{4-[4-(2-hydroxy-2-methylpropionyl)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, 2-[2-oxo-2-phenylacetoxyethoxy]ethyl oxyphenylacetate, 2-[2-hydroxyethoxy]ethyl oxyphenylacetate, methyl benzoylformate, bis(2,4,6-trimethylbenzoyl)phenylphosphine oxide, 2,4,6-trimethylbenzoyl diphenylphosphine oxide, 2,4,6-trimethylbenzoyl diphenylphosphine ester, 1-[4-(phenylthio)phenyl]-1,2-octanedione 2-(O-benzoyl oxime), 1-[9-ethyl-6-(2-methylbenzoyl)-9H-carbazole-3-yl]-acetone-1-(O-acetyl oxime), etc.

[0128] From the viewpoint of being able to further reduce the in-plane phase difference of the optically shaped body, the photopolymerization initiator (C) preferably contains a hydroxyphenyl ketone initiator, more preferably 1-hydroxycyclohexylphenyl ketone (e.g., Omnirad 184, manufactured by IGMresins).

[0129] From the viewpoint of improving the curability of the photocurable resin composition, when the total content of monofunctional (meth)acrylate monomer (A1) and difunctional or more (meth)acrylate monomer (A2) is set to 100 parts by mass, the content of 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.

[0130] From the viewpoint of improving the uniformity of the thickness of the photocurable resin composition during curing, when the total content of monofunctional (meth)acrylate monomer (A1) and difunctional or more (meth)acrylate monomer (A2) is set to 100 parts by mass, the content of 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.

[0131] From the viewpoints of improving the curability of the photocurable resin composition and improving the uniformity of the thickness of the photocurable resin composition during curing, when the total content of monofunctional (meth)acrylate monomer (A1) and difunctional or more (meth)acrylate monomer (A2) is set to 100 parts by mass, the content of 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.

[0132] From the viewpoint of further reducing the in-plane phase difference of the optically molded body, when the total amount of solid components in the photocurable resin composition (the total amount of components remaining as solid substances when the cured product is made) is set to 100% by mass, the content of 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 4.0% by mass or less.

[0133] <Light Stabilizer (D)>

[0134] The photocurable resin composition of this embodiment may further include a light stabilizer (D). There are no particular limitations on the light stabilizer (D), and known light stabilizers can be used. By including the light stabilizer (D), the photocurable resin composition can improve its colorfastness.

[0135] From the viewpoint of further improving colorfastness, the light stabilizer (D) preferably contains a hindered amine light stabilizer.

[0136] Examples of hindered amine-based light stabilizers include (1,2,2,6,6-pentamethylpiperidin-4-yl) methacrylate, bis(2,2,6,6-tetramethyl-1-(octoxy)-4-piperidinyl) sebacate, a substance consisting of 70% by mass of the reaction product of 1,1-dimethylethyl hydroperoxide and octane and 30% by mass of polypropylene, bis(1,2,2,6,6-pentamethyl-4-piperidinyl)[[3,5-bis(1,1-dimethylethyl)-4-hydroxyphenyl]methyl]butylmalonate, and bis(1,2,2,6,6-pentamethyl-4-piperidinyl) sebacate and methyl-1,2,2,6,6-pentamethyl Mixtures of 4-piperidinyl sebacate, bis(2,2,6,6-tetramethyl-4-piperidinyl) sebacate, tetra(2,2,6,6-tetramethyl-4-piperidin) ester of 1,2,3,4-butanetetracarboxylate, tetra(1,2,2,6,6-pentamethyl-4-piperidin) ester of 1,2,3,4-butanetetracarboxylate, mixtures of 2,2,6,6-tetramethyl-4-piperidin ester of 1,2,3,4-butanetetracarboxylate and tridecyl ester of 1,2,3,4-butanetetracarboxylate, mixtures of 1,2,2,6,6-pentamethyl-4-piperidin ester of 1,2,3,4-butanetetracarboxylate and tridecyl ester of 1,2,3,4-butanetetracarboxylate, etc.

[0137] From the viewpoint of further improving colorfastness, the light stabilizer (D) preferably contains 1,2,2,6,6-pentamethyl-4-piperidinium methacrylate (e.g., ADK STAB LA-82, manufactured by ADEKA Co., Ltd.).

[0138] From the viewpoint of improving the colorfastness of optically molded articles, when the total amount of solid components in the photocurable resin composition (the total amount of components remaining as solid substances when the cured product is made) is set to 100% by mass, the content of 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, and even more preferably 0.090% by mass or more.

[0139] From the viewpoint of reducing exudation, when the total amount of solid components in the photocurable resin composition (the total amount of components that remain as solid substances when the cured product is made) is set to 100% by mass, the content of light stabilizer (D) in the photocurable resin composition of this embodiment is preferably 1.00% 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 even more preferably 0.30% by mass or less.

[0140] From the viewpoints of improving the colorfastness of optically molded articles and reducing exudation, when the total amount of solid components in the photocurable resin composition (the total amount of components remaining as solid matter when the cured product is made) is set to 100% by mass, the content of light stabilizer (D) in the photocurable resin composition of this embodiment is preferably 0.0010% by mass or more and 1.00% 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, and even more preferably 0.090% by mass or more and 0.30% by mass or less.

[0141] <Other Ingredients>

[0142] The photocurable resin composition may contain one or more selected from the group consisting of fillers, curing accelerators, plasticizers, heat stabilizers, flame retardants, antistatic agents, defoamers, silane coupling agents, ultraviolet absorbers, surfactants, and leveling agents as specific examples of other components besides polymerizable compounds (e.g., monofunctional (meth)acrylate monomers (A1), difunctional or more (meth)acrylate monomers (A2)), antioxidants (B), photopolymerization initiators (C), and light stabilizers (D).

[0143] <Method for manufacturing photocurable resin compositions>

[0144] The photocurable resin composition of this embodiment can be obtained by mixing a polymerizable compound (e.g., a monofunctional (meth)acrylate monomer (A1) or a (meth)acrylate monomer (A2) with other components such as an antioxidant (B), a photopolymerization initiator (C), or a light stabilizer (D) as required, using conventionally known methods.

[0145] <Physical Properties of Photocurable Resin Compositions>

[0146] Next, the physical properties of the photocurable resin composition will be described.

[0147] The in-plane phase difference Re, measured according to the following <Measurement of In-Plane Phase Difference Re>, is described for the cured film prepared using the photocurable resin composition of this embodiment according to the <Curing Film Preparation Conditions> below.

[0148] From the viewpoint of further reducing the in-plane phase difference of the optically molded body, the in-plane phase difference Re of the photocurable resin composition of this embodiment is preferably 50.0 nm or less, more preferably 40.0 nm or less, even more preferably 35.0 nm or less, even more preferably 30.0 nm or less, even more preferably 25.0 nm or less, even more preferably 23.0 nm or less, even more preferably 20.0 nm or less, even more preferably 15.0 nm or less, even more preferably 12.0 nm or less, even more preferably 10.0 nm or less, even more preferably 8.0 nm or less, even more preferably 6.0 nm or less, even more preferably 5.0 nm or less.

[0149] The lower limit of the in-plane phase difference Re of the photocurable resin composition in this embodiment is not particularly limited. For example, it can be 0.00 nm or more, 0.10 nm or more, 0.50 nm or more, 1.0 nm or more, 2.0 nm or more, or 3.0 nm or more.

[0150] From the viewpoint of further reducing the in-plane phase difference of the optically molded body, the in-plane phase difference Re of the photocurable resin composition of this embodiment is preferably 0.00 nm or more and 50.0 nm or less, more preferably 0.00 nm or more and 40.0 nm or less, even more preferably 0.00 nm or more and 35.0 nm or less, even more preferably 0.00 nm or more and 30.0 nm or less, even more preferably 0.00 nm or more and 25.0 nm or less, even more preferably 0.00 nm or more and 23.0 nm or less, even more preferably 0.00 nm or more and 20.0 nm or less, even more preferably 0.00 nm or more and 15.0 nm or less, even more preferably 0.00 nm or more and 12.0 nm or less, even more preferably 0.00 nm or more and 10.0 nm or less, even more preferably 0.00 nm or more and 8.0 nm or less, even more preferably 0.00 nm or more and 6.0 nm or less, even more preferably 0.00 nm or more and 5.0 nm or less.

[0151] <Conditions for Curing Film Production>

[0152] A 3mm thick, 50mm x 50mm silicone sheet (material: silicone rubber, hardness: 50 degrees) with a 35mm φ circular hole is placed on a 0.7mm thick, 50mm x 50mm alkali-free glass substrate. The aforementioned photocurable resin composition is filled into the circular hole. Another 0.7mm thick, 50mm x 50mm alkali-free glass substrate is then placed on top. The substrate is placed on an SUS-made laboratory lift platform with its height adjusted. The photocurable resin composition is irradiated with 405nm LED light at 810mW for 3 minutes from above the alkali-free glass. The substrate is then flipped, and irradiation with 405nm LED light at 810mW for another 3 minutes is performed. After irradiation with LED light, the substrate is allowed to cool naturally at 23°C for 30 minutes. The cured photocurable resin composition is then demolded from the alkali-free glass and the silicone sheet to obtain a cured film of the aforementioned photocurable resin composition.

[0153] Here, the more specific manufacturing conditions for the cured film of the photocurable resin composition of this embodiment can be, for example, the conditions described in the examples.

[0154] <Determination of in-plane phase difference Re>

[0155] For the cured film, one hour after the LED light irradiation is completed, the in-plane phase difference Re at a distance of 10.0 mm from the center of the cured film is measured using a two-dimensional birefringence evaluation device at an ambient temperature of 23°C and atmospheric conditions.

[0156] In this embodiment, more specifically, the in-plane phase difference Re can be measured according to the method described in the embodiments.

[0157] Next, the in-plane phase difference Re after heating, measured according to the following <Measurement of In-plane Phase Difference Re after Heat Treatment>, is explained after the curing film prepared using the photocurable resin composition of this embodiment according to the <Curing Film Preparation Conditions> described above is subjected to the following <Heat Treatment>.

[0158] From the viewpoint of further reducing the in-plane phase difference of the optically molded body, the in-plane phase difference Re of the photocurable resin composition after heating in this embodiment is preferably 16.0 nm or less, more preferably 13.0 nm or less, even more preferably 10.0 nm or less, even more preferably 8.0 nm or less, even more preferably 6.0 nm or less, even more preferably 5.0 nm or less, even more preferably 4.0 nm or less, even more preferably 3.5 nm or less, even more preferably 3.0 nm or less, even more preferably 2.5 nm or less.

[0159] The lower limit of the in-plane phase difference Re after heating of the photocurable resin composition in this embodiment is not particularly limited. For example, it can be 0.00 nm or more, 0.10 nm or more, 0.50 nm or more, 1.0 nm or more, 2.0 nm or more, or 3.0 nm or more.

[0160] From the viewpoint of further reducing the in-plane phase difference of the optically molded body, the in-plane phase difference Re of the photocurable resin composition after heating in this embodiment is preferably 0.00 nm or more and 16.0 nm or less, more preferably 0.00 nm or more and 13.0 nm or less, even more preferably 0.00 nm or more and 10.0 nm or less, even more preferably 0.00 nm or more and 8.0 nm or less, even more preferably 0.00 nm or more and 6.0 nm or less, even more preferably 0.00 nm or more and 5.0 nm or less, even more preferably 0.00 nm or more and 4.0 nm or less, even more preferably 0.00 nm or more and 3.5 nm or less, even more preferably 0.00 nm or more and 3.0 nm or less, even more preferably 0.00 nm or more and 2.5 nm or less.

[0161] <Heat Treatment>

[0162] The cured film was heated from 23°C to 120°C at a constant rate over 1 hour, heated at 120°C for 1 hour, cooled from 120°C to 23°C at a constant rate over 3 hours, and then exothermized at 23°C for 3 hours.

[0163] <Determination of in-plane phase difference Re after heat treatment>

[0164] For the cured film, one hour after the completion of the above-mentioned heat treatment, the in-plane phase difference Re at a distance of 10.0 mm from the center of the cured film is measured using a two-dimensional birefringence evaluation device at an ambient temperature of 23°C and under atmospheric conditions.

[0165] <Uses of UV-curable resin compositions>

[0166] Next, the uses of the photocurable resin composition will be explained.

[0167] The photocurable resin composition of this embodiment can reduce the in-plane phase difference of optical molded articles formed from the photocurable resin composition, and therefore can be used in methods for forming optical molded articles such as injection molding, compression molding, injection compression molding, extrusion molding, solution casting, and casting. In particular, the photocurable resin composition of this embodiment can be used in the casting process.

[0168] The photocurable resin composition of this embodiment can reduce the in-plane phase difference of the optical molded body formed by the photocurable resin composition. Therefore, the application of the optical molded body formed by the photocurable resin composition is not particularly limited and can be used for various purposes.

[0169] The photocurable resin composition of this embodiment is preferably used for lenses, for example. As a lens, it may include, for example, one or more 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.

[0170] The photocurable resin composition of this embodiment can, for example more preferably, be used in one or more lenses selected from the group consisting of lenses for virtual reality devices (VR lenses), mixed reality devices (MR lenses), augmented reality devices (AR lenses), extended reality devices (xR lenses), and head-mounted display lenses (HMD lenses).

[0171] The photocurable resin composition of this embodiment can preferably be used, for example, as a cover plate for a display (hereinafter also referred to as a cover display). As a cover display, it may include, for example, one or more types selected from the group consisting of front cover displays and full-cover displays.

[0172] The photocurable resin composition of this embodiment can, for example, more preferably, be used in one or more overlay displays selected from the group consisting of overlay displays for virtual reality devices (VR devices), overlay displays for mixed reality devices (MR devices), overlay displays for augmented reality devices (AR devices), overlay displays for extended reality devices (xR devices), and overlay displays for head-mounted displays (HMDs).

[0173] (cured material)

[0174] The cured product of this embodiment is a cured product of the photocurable resin composition of this embodiment. The cured product of this embodiment can be manufactured, for example, by irradiating the photocurable resin composition of this embodiment with LED light to cure it. It should be noted that more specific manufacturing conditions for the cured product of this embodiment can be, for example, the conditions described in the examples.

[0175] (Optically shaped body)

[0176] The optical molded body of this embodiment comprises 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.

[0177] The optical molding body of this embodiment includes a lens. The lens may include, for example, one or more types 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.

[0178] The lens in this embodiment includes one or more types 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 extended reality devices (xR lenses), and lenses for head-mounted displays (HMD lenses).

[0179] The optical molding body of this embodiment includes a cover plate for a display (covered display). As a covered display, it includes, for example, one or more types selected from the group consisting of front covered displays and full-surface covered displays.

[0180] The overlay display in this embodiment includes one or more types selected from the group consisting of an overlay display for virtual reality devices (VR devices), an overlay display for mixed reality devices (MR devices), an overlay display for augmented reality devices (AR devices), an overlay display for extended reality devices (xR devices), and an overlay display for head-mounted displays (HMDs).

[0181] The thickest part of an optical molded body is the part with the greatest thickness of the optical components within it. The location of the thickest part of the optical molded body is not particularly limited and can be appropriately set according to the application, etc.

[0182] For example, in this embodiment, the optically shaped body preferably has a maximum thickness of 1.0 mm or more, more preferably 1.1 mm or more, even more preferably 1.2 mm or more, even more preferably 1.5 mm or more, even more preferably 2.0 mm or more, even more preferably 3.0 mm or more, even more preferably 4.0 mm or more, and even more preferably 5.0 mm or more.

[0183] For example, in this embodiment, the maximum thickness of the optical molded body is preferably 20.0 mm or less, more preferably 19.9 mm or less, even more preferably 19.8 mm or less, even more preferably 19.5 mm or less, even more preferably 18.0 mm or less, even more preferably 17.0 mm or less, even more preferably 16.0 mm or less, and even more preferably 15.0 mm or less.

[0184] For example, in this embodiment, the optical forming body preferably has a maximum thickness of 1.0 mm or more and 20.0 mm or less, more preferably 1.1 mm or more and 19.9 mm or less, even more preferably 1.2 mm or more and 19.8 mm or less, even more preferably 1.5 mm or more and 19.5 mm or less, even more preferably 2.0 mm or more and 19.0 mm or less, even more preferably 3.0 mm or more and 18.0 mm or less, even more preferably 4.0 mm or more and 17.0 mm or less, even more preferably 5.0 mm or more and 16.0 mm or less, and even more preferably 5.0 mm or more and 15.0 mm or less.

[0185] It should be noted that the photocurable resin composition of this embodiment can reduce the in-plane phase difference of the optical molded body, and therefore can also be applied to optical molded bodies with a thickness of 1.0 mm or more.

[0186] (Optical equipment)

[0187] The optical device of this embodiment includes the optical molding body of this embodiment. The type of optical device in this embodiment is not particularly limited. Examples of optical devices in this embodiment include virtual reality devices (VR devices), mixed reality devices (MR devices), augmented reality devices (AR devices), extended reality devices (xR devices), and head-mounted displays (HMD devices).

[0188] The embodiments of the present invention have been described above, but these are merely examples of the present invention, and various configurations other than those described above are also possible.

[0189] Furthermore, the present invention is not limited to the embodiments described above, and modifications and improvements made within the scope of not impairing the effects of the present invention are included in the present invention.

[0190] Example

[0191] Hereinafter, this embodiment will be described in detail with reference to examples and the like. However, this embodiment is not limited in any way by the descriptions in these examples.

[0192] First, the materials used in each example are shown.

[0193] Polymerizable compound: (meth)acrylate monomer (A)

[0194] Monofunctional (meth)acrylate monomer (A1)1: GM81HDA (dicyclopentyl methacrylate, manufactured by Guojing Chemical Co., Ltd.)

[0195] 2 or more functional (meth)acrylate monomers (A2)1: DDD (1,12-dodecanediol dimethacrylate, manufactured by Shin-Nakamura Chemical Industry Co., Ltd.)

[0196] 2-functional or higher (meth)acrylate monomers (A2)2:DCP (tricyclodecanediethanol dimethacrylate, manufactured by Shin-Nakamura Chemical Industry Co., Ltd.)

[0197] 2- or higher functional (meth)acrylate monomers (A2)3: GM82R2E (2,2-bis[4-[2-(methacryloyloxy)ethoxy]phenyl]propane, manufactured by Kokusei Chemical Co., Ltd.)

[0198] • Antioxidants (B)

[0199] Antioxidant 1: Thioether-based antioxidant (bis[3-(dodecylthio)propionic acid]2,2-bis[[3-(dodecylthio)-1-oxopropoxy]methyl]-1,3-propanediyl ester, manufactured by ADEKA Co., Ltd., product name: ADK STAB AO-412S) (hereinafter also referred to as AO-412S)

[0200] Antioxidant 2: Phenolic antioxidant (Pentaerythritol tetra[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate], manufactured by ADEKA Co., Ltd., product name: ADK STAB AO-60) (hereinafter also referred to as AO-60)

[0201] Photopolymerization initiator (C)

[0202] Photopolymerization initiator 1: Photoradical polymerization initiator (1-hydroxycyclohexylphenyl ketone, manufactured by IGM Resins, product name: Omnirad 184)

[0203] • Light stabilizer (D)

[0204] Light stabilizer 1: Hindered amine light stabilizer (1,2,2,6,6-pentamethyl-4-piperidinyl methacrylate, manufactured by ADEKA Corporation, product name: ADK STAB LA-82) (hereinafter also referred to as LA-82)

[0205] (Examples 1-3, Comparative Example 1)

[0206] The components were combined in the manner shown in Table 1 to obtain a liquid photocurable resin composition. The units for the composition in Table 1 are parts by mass.

[0207] The physical properties of optically molded articles obtained from the photocurable resin compositions of each example were determined by the following methods. The results are shown in Table 1.

[0208] <Determination of in-plane phase difference Re>

[0209] Using the photocurable resin compositions of each example, the in-plane phase difference Re of the cured film prepared according to the <Curing Film Preparation Conditions> below was measured according to the <Measurement of In-Plane Phase Difference Re> below.

[0210] <Conditions for Curing Film Production>

[0211] A 3mm thick, 50mm x 50mm silicone sheet (material: silicone rubber, hardness: 50 degrees) with a 35mm φ circular hole is placed on a 0.7mm thick, 50mm x 50mm alkali-free glass (product name: JIS R 3202, lightly chamfered glass plate, manufactured by TestPiece). After filling the circular hole portion of the silicone sheet with a photocurable resin composition, a 0.7mm thick, 50mm x 50mm alkali-free glass sheet (product name: JIS R 3202, lightly chamfered glass plate, manufactured by TestPiece) is further placed on top. At this time, it is confirmed that no air bubbles are introduced. Hereinafter, the component formed by placing a silicone sheet on the above-mentioned alkali-free glass, filling the circular hole portion of the silicone sheet with a photocurable resin composition, and then further placing alkali-free glass on top is sometimes referred to as a laminate.

[0212] The obtained laminate was placed on a SUS-made laboratory lift platform with its height adjusted. Using an LED irradiation device (CCS, product name: 405nm-120mm air-cooled intermittent irradiation device, model: HLDL-120505-NWPSC), the photocurable resin composition was irradiated with 405nm LED light at 810mW for 3 minutes from above the alkali-free glass. Then, the laminate was flipped and irradiated with 405nm LED light at 810mW for 3 minutes. After irradiation, it was allowed to cool naturally at 23°C for 30 minutes. After natural cooling, the cured photocurable resin composition was demolded from the alkali-free glass and silicone wafer to obtain a cured film of the photocurable resin composition.

[0213] It should be noted that the intensity of the LED light irradiation was measured using an ultraviolet cumulative photometer (product name: UIT-250, manufactured by USHIO Electric Co., Ltd.).

[0214] <Determination of in-plane phase difference Re>

[0215] For each example of the cured film, one hour after the LED light irradiation is completed, the in-plane phase difference Re at a distance of 10.0 mm from the center of the cured film is measured using a two-dimensional birefringence evaluation device at an ambient temperature of 23°C and under atmospheric conditions, according to the following <Measurement Conditions for In-Plane Phase Difference Re> and the following <Measurement Procedure>.

[0216] <Conditions for measuring in-plane phase difference Re>

[0217] • Apparatus: Two-dimensional birefringence evaluation apparatus (Product name: WPA-200, manufactured by Photonic Lattice)

[0218] Analysis software: WPA-view

[0219] • Measurement temperature: 23℃

[0220] • Atmospheric pressure

[0221] • Selected area: Within a radius of 17.5 mm from the center of the cured film.

[0222] • Analysis area: Within a radius of 10.0 mm from the center of the cured film.

[0223] • Measurement field of view: 30mm × 40mm

[0224] • Birefringence pixel count: 384×288 pixels

[0225] • Lens: Standard lens (f 1.25)

[0226] User settings

[0227] Automatic exposure adjustment: Automatic exposure adjustment is performed during measurement.

[0228] Noise Filter: Automatic Application

[0229] Masking of dark areas: Apply masking (10.0%)

[0230] Axial setting: Slow axis

[0231] Measurement accuracy: High precision

[0232] Measurement mode: 3-wavelength measurement

[0233] Measurement wavelengths: 523nm, 543nm, 575nm

[0234] Material coefficient: Automatic

[0235] <Measurement Steps>

[0236] (S1) After turning on the power to the device and starting the software (WPA-view), wait at least 30 minutes for it to stabilize.

[0237] (S2) After placing the curing film on the light source stage, adjust the height of the camera unit while retracting the curing film into the area of ​​the light source stage reflected in the camera preview window. At this time, prevent the curing film from floating off the light source stage. Additionally, visually confirm in the preview window that no external light is reflected.

[0238] (S3) While rotating the scale of the lens, focus on the cured film. During the measurement of the cured film, align the scale of the lens with "4".

[0239] (S4) The above conditions were set in the user settings. Next, the cured film was temporarily removed, and the baseline was measured. The baseline was measured for each cured film.

[0240] (S5) After re-preparing the cured film, the measurement was carried out.

[0241] (S6) On the analysis screen, after adjusting the selected area to enter the measurement field of view as described above, measure the in-plane phase difference Re, etc.

[0242] <Determination of in-plane phase difference Re after heating>

[0243] The cured films prepared using the photocurable resin composition according to the above-described <curing film preparation conditions> were subjected to the following <heat treatment>. The in-plane phase difference Re after heating, as measured according to the following <determination of in-plane phase difference Re after heat treatment>, was determined for each example of the cured film after the following <heat treatment>.

[0244] It should be noted that the heating of the curing film in each example began more than 1 hour but less than 3 hours after the curing film was made.

[0245] <Heat Treatment>

[0246] The cured film was heated from 23°C to 120°C at a constant rate over 1 hour, heated at 120°C for 1 hour, cooled from 120°C to 23°C at a constant rate over 3 hours, and then exothermized at 23°C for 3 hours.

[0247] <Determination of in-plane phase difference Re after heat treatment>

[0248] For the cured film, one hour after the completion of the above-mentioned heat treatment, the in-plane phase difference Re at a distance of 10.0 mm from the center of the cured film is measured using a two-dimensional birefringence evaluation device at an ambient temperature of 23°C and atmospheric conditions.

[0249] [Table 1]

[0250]

[0251] This application claims priority based on Japanese Patent Application No. 2024-012864, filed on January 31, 2024, the entire contents of which are incorporated herein by reference.

Claims

1. A photocurable resin composition, which is a photocurable resin composition suitable for use in optically molded articles. The photocurable resin composition comprises a (meth)acrylate monomer with two or more functionalities, wherein the (meth)acrylate monomer with two or more functionalities comprises one or more selected from the group consisting of alicyclic difunctional (meth)acrylate monomers and linear difunctional (meth)acrylate monomers. When the total content of the above-functional (meth)acrylate monomers is set to 100 parts by mass, the total content of the alicyclic difunctional (meth)acrylate monomer and the linear difunctional (meth)acrylate monomer is 60 parts by mass or more and 100 parts by mass or less.

2. The photocurable resin composition according to claim 1, comprising one or more monomers selected from the group consisting of monofunctional (meth)acrylate monomers and difunctional (meth)acrylate monomers. When the total content of the monofunctional (meth)acrylate monomer and the (meth)acrylate monomer with two or more functions is set to 100 parts by mass, the content of the (meth)acrylate monomer with two or more functions is 5.0 parts by mass or more and 90 parts by mass or less.

3. The photocurable resin composition according to claim 2, comprising the monofunctional (meth)acrylate monomer.

4. The photocurable resin composition according to claim 2 or 3, wherein, The monofunctional (meth)acrylate monomer has an alicyclic skeleton.

5. The photocurable resin composition according to any one of claims 1 to 4, wherein, The cured film prepared using the aforementioned photocurable resin composition according to the following <curing film preparation conditions> has an in-plane phase difference Re of 50.0 nm or less, as measured according to the following <determination of in-plane phase difference Re>. <Conditions for Curing Film Production> A 3mm thick, 50mm × 50mm silicone sheet with a 35mm φ circular hole is placed on a 0.7mm thick, 50mm × 50mm alkali-free glass substrate. The silicone sheet is made of silicone rubber with a hardness of 50 degrees. After filling the circular hole with the photocurable resin composition, another 0.7mm thick, 50mm × 50mm alkali-free glass substrate is placed on top. The substrate is placed on an SUS-made laboratory lift platform with adjustable height. The photocurable resin composition is irradiated with 405nm LED light at 810mW for 3 minutes from above the alkali-free glass. After flipping the substrate, it is irradiated with 405nm LED light at 810mW for another 3 minutes. After natural cooling at 23°C for 30 minutes, the cured photocurable resin composition is demolded from the alkali-free glass and the silicone sheet to obtain a cured film of the photocurable resin composition. <Determination of in-plane phase difference Re> For the cured film, one hour after the LED light irradiation is completed, the in-plane phase difference Re at a distance of 10.0 mm from the center of the cured film is measured using a two-dimensional birefringence evaluation device at an ambient temperature of 23°C and atmospheric conditions.

6. The photocurable resin composition according to any one of claims 1 to 5, wherein, After subjecting the cured film prepared using the aforementioned photocurable resin composition to the following <curing film preparation conditions> to the following <heat treatment>, the in-plane phase difference Re after heating, as measured according to the following <determination of in-plane phase difference Re after heat treatment>, is 16.0 nm or less. <Conditions for Curing Film Production> A 3mm thick, 50mm × 50mm silicone sheet with a 35mm φ circular hole is placed on a 0.7mm thick, 50mm × 50mm alkali-free glass substrate. The silicone sheet is made of silicone rubber with a hardness of 50 degrees. After filling the circular hole with the photocurable resin composition, another 0.7mm thick, 50mm × 50mm alkali-free glass substrate is placed on top. The substrate is placed on an SUS-made laboratory lift platform with adjustable height. The photocurable resin composition is irradiated with 405nm LED light at 810mW for 3 minutes from above the alkali-free glass. After flipping the substrate, it is irradiated with 405nm LED light at 810mW for another 3 minutes. After natural cooling at 23°C for 30 minutes, the cured photocurable resin composition is demolded from the alkali-free glass and the silicone sheet to obtain a cured film of the photocurable resin composition. <Heat Treatment> The cured film was heated from 23°C to 120°C at a constant rate over 1 hour, heated at 120°C for 1 hour, and then cooled from 120°C to 23°C at a constant rate over 3 hours. Finally, it was heated at 23°C for 3 hours to release heat. <Determination of in-plane phase difference Re after heat treatment> For the cured film, one hour after the completion of the <heat treatment>, the in-plane phase difference Re at a distance of 10.0 mm from the center of the cured film is measured using a two-dimensional birefringence evaluation device at an ambient temperature of 23°C and under atmospheric conditions.

7. The photocurable resin composition according to any one of claims 1 to 6, further comprising an antioxidant.

8. The photocurable resin composition according to any one of claims 1 to 7, further comprising a photopolymerization initiator.

9. The photocurable resin composition according to claim 8, wherein, The photopolymerization initiator includes a photoradical polymerization initiator.

10. The photocurable resin composition according to any one of claims 1 to 9, further comprising a light stabilizer.

11. The photocurable resin composition according to any one of claims 1 to 10, which can be used in casting.

12. The photocurable resin composition according to any one of claims 1 to 11, which can be used 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 extended reality devices (xR lenses), and lenses for head-mounted displays (HMD lenses).

13. A cured product of the photocurable resin composition according to any one of claims 1 to 12.

14. An optically molded article comprising a cured product of the photocurable resin composition according to any one of claims 1 to 12.

15. The optically shaped article according to claim 14, wherein, The optical molding includes a lens.

16. The optically shaped article according to claim 15, wherein, The lens includes one or more types selected from the group consisting of a VR lens for virtual reality devices, a MR lens for mixed reality devices, an AR lens for augmented reality devices, an xR lens for extended reality devices, and an HMD lens for head-mounted displays.

17. The optically shaped article according to any one of claims 14 to 16, wherein, The maximum thickness is less than 20.0 mm.

18. The optically shaped article according to any one of claims 14 to 17, wherein, The maximum thickness is 1.0 mm or more.

19. An optical device comprising the optical molding body according to any one of claims 14 to 18.

Images