Photocurable resin composition, cured product, and optical molded body

Abstract

This photocurable resin composition contains: a (meth)acrylate monomer (A) having an alicyclic skeleton; a (meth)acrylate polymer (B) having an alicyclic skeleton; and a photopolymerization initiator (C).

Description

Photocurable resin composition, cured product, and optical molded product

[0001] The present invention relates to a photocurable resin composition, a cured product, and an optical molded product.

[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] A first embodiment of the present invention provides a photocurable resin composition that can give an optical molded article having an improved balance of moldability and transparency.

[0007] A second embodiment of the present invention provides a photocurable resin composition that can reduce the occurrence of cracks in an optical molded body.

[0008] The present inventors have conducted extensive research to achieve the object of the first embodiment. As a result, they have found that an optical molded body having an improved balance of moldability and transparency can be obtained by using a photocurable resin composition containing (A) a (meth)acrylate monomer having an alicyclic skeleton, (B) a (meth)acrylate polymer having an alicyclic skeleton, and (C) a photopolymerization initiator, and have thus completed the first embodiment of the present invention.

[0009] [1A] A photocurable resin composition comprising: (A) a (meth)acrylate monomer having an alicyclic skeleton; (B) a (meth)acrylate polymer having an alicyclic skeleton; and (C) a photopolymerization initiator. [2A] The photocurable resin composition according to [1A], wherein the (meth)acrylate polymer (B) has a polystyrene-equivalent weight average molecular weight Mw of 3,000 or more and 5,000,000 or less, as measured by gel permeation chromatography (GPC). [3A] The photocurable resin composition according to [2A], wherein the (meth)acrylate polymer (B) has a weight average molecular weight Mw of 10,000 or more. [4A] The photocurable resin composition according to any one of [1A] to [3A], wherein the content of the (meth)acrylate polymer (B) is 0.5 parts by mass or more and 90 parts by mass or less, relative to 100 parts by mass of the (meth)acrylate monomer (A). [5A] The photocurable resin composition according to any one of [1A] to [4A], wherein the (meth)acrylate monomer (A) and the (meth)acrylate polymer (B) have one or more skeletons selected from the group consisting of an adamantane skeleton, a norbornane skeleton, a dicyclopentadiene skeleton, an isobornyl skeleton, and a cyclohexane skeleton. [6A] The photocurable resin composition according to any one of [1A] to [5A], wherein the (meth)acrylate monomer (A) is monofunctional or difunctional or higher. [7A] The photocurable resin composition according to any one of [1A] to [6A], further comprising a monofunctional or difunctional or higher functional (meth)acrylate monomer (excluding the (meth)acrylate monomer (A)). [8A] The photocurable resin composition according to any one of [1A] to [7A], wherein the viscosity of the photocurable resin composition is 110 mPa·s or more and 5000 mPa·s or less, as measured using an E-type viscometer at a temperature of 25°C and a rotation speed of 2.5 rpm. [9A] The photocurable resin composition according to any one of [1A] to [8A], wherein the haze value of a cured film prepared according to the following <Cured Film Preparation Conditions> at a thickness of 3.0 mm, as measured in accordance with JIS K 7136:2000, is less than 1.0%.<Conditions for Producing a Cured Film> 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 was placed on a 0.7 mm thick, 50 mm x 50 mm alkali-free glass sheet. The circular hole was filled with the photocurable resin composition, and then a 0.7 mm thick, 50 mm x 50 mm alkali-free glass sheet was placed on top of the silicone-free glass sheet. The height was adjusted by placing this on a stainless steel lab jack. The photocurable resin composition was irradiated with LED light having a wavelength of 405 nm at 810 mW from above the alkali-free glass sheet for 3 minutes, then turned over and irradiated with LED light having a wavelength of 405 nm at 810 mW for 3 minutes. The glass sheet was then allowed to cool at 23°C for 30 minutes, and the cured product of the photocurable resin composition was released from the alkali-free glass sheet and the silicone sheet to obtain a cured film. [10A] The photocurable resin composition according to any one of [1A] to [9A] above, further comprising a chain transfer agent. [11A] The photocurable resin composition according to any one of [1A] to [10A] above, further comprising an antioxidant. [12A] The photocurable resin composition according to any one of [1A] to [11A] above, wherein the photopolymerization initiator (C) comprises a photoradical polymerization initiator. [13A] The photocurable resin composition according to any one of [1A] to [12A] above, further comprising a light stabilizer. [14A] The photocurable resin composition according to any one of [1A] to [13A] above, which can be used in a casting method. [15A] The photocurable resin composition according to any one of [1A] to [14A] above, which can be used for one or more lenses selected from the group consisting of virtual reality lenses (VR lenses), mixed reality lenses (MR lenses), augmented reality lenses (AR lenses), cross reality lenses (xR lenses), and head-mounted display lenses (HMD lenses). [16A] The photocurable resin composition according to any one of [1A] to [15A] above, wherein a cured film produced according to the following <Cured Film Production Conditions> has a humidity swelling ratio α1 of 0.35% or less, as measured according to the following <Humidity-Conditioned Thermomechanical Analysis (Humidity-Conditioned TMA)>.<Conditions for Producing a Cured Film> A 100 μm thick, 100 mm x 100 mm PET film and a 500 μm thick, 100 mm x 100 mm silicone sheet (material: silicone rubber, hardness: 50 degrees) with a 50 mm diameter circular hole were placed in this order on a 2.0 mm thick, 100 mm x 100 mm alkali-free glass sheet, and the circular hole was filled with the photocurable resin composition. Then, a 100 μm thick, 100 mm x 100 mm PET film and a 2.0 mm thick, 100 mm x 100 mm alkali-free glass sheet were placed on top of the 100 μm thick, 100 mm x 100 mm PET film and the 2.0 mm thick, 100 mm x 100 mm alkali-free glass sheet. The above-mentioned items are further placed in this order, and this is placed on an SUS lab jack to adjust the height. One of the alkali-free glasses is irradiated with LED light having a wavelength of 405 nm at 810 mW for 3 minutes onto the photocurable resin composition, and then the glass is turned over and irradiated with LED light having a wavelength of 405 nm at 810 mW for 3 minutes. The glass is then allowed to cool at 23°C for 30 minutes, and the cured product of the photocurable resin composition is released from the alkali-free glass, the PET film, and the silicone sheet to obtain a cured film. <Humidity-Conditioned Thermomechanical Analysis (Humidity-Conditioned TMA)> The cured film was cut into a strip of 5 mm wide and 15 mm long to prepare a test piece, and subjected to humidity-conditioned thermomechanical analysis (humidity-conditioned TMA) in a tensile mode with a load of 5 gf, a chuck distance of 10 mm, in a nitrogen atmosphere, and at a constant temperature of 65°C. The test pieces were subjected to the following consecutive steps: maintaining a humidity of 0% RH for 30 minutes, increasing the humidity from 0% RH to 90% RH at a humidity increase rate of 5% RH / min (humidity increase step), maintaining a humidity of 90% RH for 150 minutes, decreasing the humidity from 90% RH to 0% RH at a humidity decrease rate of 5% RH / min (humidity decrease step), and maintaining a humidity of 0% RH for 55 minutes. The humidity swelling ratio in the humidity increase step was designated as the humidity swelling ratio α1. [17A] A cured product of the photocurable resin composition according to any one of [1A] to [16A] above. [18A] An optical molded body comprising a cured product of the photocurable resin composition according to any one of [1A] to [16A]. [19A] The optical molded body according to [18A], wherein the optical molded body comprises a lens.[20A] The optical molded body according to [19A], wherein the lens comprises 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). [21A] The optical molded body according to any one of [18A] to [20A], wherein the maximum thickness portion is 20.0 mm or less. [22A] The optical molded body according to any one of [18A] to [21A], wherein the maximum thickness portion is 1.0 mm or more.

[0010] The present inventors conducted extensive research to achieve the objectives of the second embodiment. As a result, they found that the humidity swelling rate of a photocurable resin composition measured under specific conditions correlates with the occurrence of cracks in the resulting optical molded body. Based on this finding, the present inventors conducted further extensive research and found that the occurrence of cracks in the optical molded body can be reduced by using a photocurable resin composition containing a (meth)acrylate monomer (A) having an alicyclic skeleton, a (meth)acrylate polymer (B) having an alicyclic skeleton, and a photopolymerization initiator (C), and having a humidity swelling rate of 0.35% or less measured under specific conditions. This led to the completion of the second embodiment of the present invention.

[0011] [1B] A photocurable resin composition comprising: (A) a (meth)acrylate monomer having an alicyclic skeleton; (B) a (meth)acrylate polymer having an alicyclic skeleton; and (C) a photopolymerization initiator, wherein a cured film produced according to the following <Cured Film Production Conditions> has a humidity swelling ratio α1 of 0.35% or less, as measured according to the following <Humidity-Conditioned Thermomechanical Analysis (Humidity-Conditioned TMA)>. <Cured Film Production Conditions> A 100 μm thick, 100 mm x 100 mm PET film and a 500 μm thick, 100 mm x 100 mm silicone sheet (material: silicone rubber, hardness: 50 degrees) with a 50 mm diameter circular hole were placed in this order on a 2.0 mm thick, 100 mm x 100 mm alkali-free glass sheet, and the circular hole was filled with the photocurable resin composition. Then, a 100 μm thick, 100 mm x 100 mm PET film and a 2.0 mm thick, 100 mm x 100 mm alkali-free glass sheet were placed on top of the 100 μm thick, 100 mm x 100 mm PET film and the 2.0 mm thick, 100 mm x 100 mm alkali-free glass sheet. The above-mentioned items are further placed in this order, and this is placed on an SUS lab jack to adjust the height. One of the alkali-free glasses is irradiated with LED light having a wavelength of 405 nm at 810 mW for 3 minutes onto the photocurable resin composition, and then the glass is turned over and irradiated with LED light having a wavelength of 405 nm at 810 mW for 3 minutes. The glass is then allowed to cool at 23°C for 30 minutes, and the cured product of the photocurable resin composition is released from the alkali-free glass, the PET film, and the silicone sheet to obtain a cured film. <Humidity-Conditioned Thermomechanical Analysis (Humidity-Conditioned TMA)> The cured film was cut into a strip having a width of 5 mm and a length of 15 mm to prepare a test piece. The test piece was subjected to humidity-conditioned thermomechanical analysis (humidity-conditioned TMA) in a tensile mode with a load of 5 gf, a chuck distance of 10 mm, in a nitrogen atmosphere, and at a constant temperature of 65°C. The following steps were successively performed: maintaining the test piece at a humidity of 0% RH for 30 minutes, increasing the humidity from 0% RH to 90% RH at a humidity increase rate of 5% RH / min (humidity increase step), maintaining the test piece at a humidity of 90% RH for 150 minutes, decreasing the humidity from 90% RH to 0% RH at a humidity decrease rate of 5% RH / min (humidity decrease step), and maintaining the test piece at a humidity of 0% RH for 55 minutes. The humidity swelling ratio in the humidity increase step was designated as the humidity swelling ratio α1.[2B] The photocurable resin composition according to [1B] above, wherein the humidity swelling rate in the humidity decreasing step is a humidity swelling rate α2, and in a cured film produced according to the <Cured Film Production Conditions> above, the humidity swelling rate α2 measured according to the <Humidity-Conditioned Thermomechanical Analysis (Humidity-Conditioned TMA)> is 0.30% or less. [3B] The photocurable resin composition according to [1B] or [2B] above, wherein in an optical molded body produced according to the <Optical Molded Body Production Conditions> below, the water absorption rate measured according to the <Water Absorption Measurement> below is 0.34% or less. <Conditions for Producing Optical Molded Body> A pair of glass molds are placed at a predetermined distance from each other, and tape is attached circumferentially to the outer peripheral surfaces of the pair of glass molds to seal the space between the pair of glass molds. The photocurable resin composition is then injected through an injection nozzle to fill the sealed space. The photocurable resin composition is then irradiated with LED light having a wavelength of 405 nm at 810 mW from above the pair of glass molds for 3 minutes, and then the glass molds are turned over and irradiated with LED light having a wavelength of 405 nm at 810 mW for 3 minutes. The glass molds are then allowed to cool at 23°C for 30 minutes, and the tape is then removed to obtain an optical molded body. <Water Absorption Measurement> The optical molded body is dried at a temperature of 23°C and a relative humidity of 5% or less for 16 hours, the pre-test mass of the optical molded body is measured, the optical molded body is then left in a thermo-hygrostat chamber at a temperature of 65°C and a relative humidity of 90% RH for 504 hours, the post-test mass of the optical molded body removed from the thermo-hygrostat chamber is measured, and the water absorption is calculated using the following formula (1): Water absorption = {(Post-test mass) - (Pre-test mass)} / (Pre-test mass) x 100 [4B] The photocurable resin composition according to any one of [1B] to [3B], wherein the (meth)acrylate polymer (B) has a polystyrene-equivalent weight average molecular weight Mw of 3,000 or more and 250,000 or less, as measured by gel permeation chromatography (GPC). [5B] The photocurable resin composition according to [4B], wherein the weight average molecular weight Mw of the (meth)acrylate polymer (B) is 50,000 or less.[6B] The photocurable resin composition according to any one of [1B] to [5B], wherein the content of the (meth)acrylate polymer (B) is 1 part by mass or more and 90 parts by mass or less when the content of the (meth)acrylate monomer (A) is 100 parts by mass. [7B] The photocurable resin composition according to any one of [1B] to [6B], wherein the (meth)acrylate monomer (A) and the (meth)acrylate polymer (B) have one or more skeletons selected from the group consisting of an adamantane skeleton, a norbornane skeleton, a dicyclopentadiene skeleton, an isobornyl skeleton, and a cyclohexane skeleton. [8B] The photocurable resin composition according to any one of [1B] to [7B], wherein the (meth)acrylate monomer (A) is monofunctional or bifunctional or higher. [9B] The photocurable resin composition according to any one of [1B] to [8B] above, further comprising a monofunctional or di- or higher functional (meth)acrylate monomer (excluding the (meth)acrylate monomer (A)). [10B] The photocurable resin composition according to any one of [1B] to [9B] above, wherein the viscosity of the photocurable resin composition is 10 mPa·s or more and 500 mPa·s or less, as measured using an E-type viscometer at a temperature of 25°C and a rotation speed of 2.5 rpm. [11B] The photocurable resin composition according to any one of [1B] to [10B] above, wherein the haze value of a cured film prepared according to the following <Cured Film Preparation Condition 2> at a thickness of 3.0 mm, as measured in accordance with JIS K 7136:2000, is less than 1.0%.<Cured Film Preparation Condition 2> 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 was placed on a 0.7 mm thick, 50 mm x 50 mm alkali-free glass sheet. The circular hole was filled with the photocurable resin composition, and then a 0.7 mm thick, 50 mm x 50 mm alkali-free glass sheet was placed on top of the silicone-free glass sheet. The glass sheet was placed on a stainless steel lab jack to adjust the height, and the photocurable resin composition was irradiated with LED light having a wavelength of 405 nm at 810 mW from above the alkali-free glass sheet for 3 minutes. The glass sheet was then turned over and irradiated with LED light having a wavelength of 405 nm at 810 mW for 3 minutes. The glass sheet was then allowed to cool at 23°C for 30 minutes, and the cured product of the photocurable resin composition was released from the alkali-free glass sheet and the silicone sheet to obtain a cured film. [12B] The photocurable resin composition according to any one of [1B] to [11B] above, wherein the photopolymerization initiator (C) comprises a photoradical polymerization initiator. [13B] The photocurable resin composition according to any one of [1B] to [12B] above, further comprising an antioxidant. [14B] The photocurable resin composition according to any one of [1B] to [13B] above, further comprising a light stabilizer. [15B] The photocurable resin composition according to any one of [1B] to [14B] above, further comprising a chain transfer agent. [16B] The photocurable resin composition according to any one of [1B] to [15B] above, which can be used in a casting method. [17B] The photocurable resin composition according to any one of [1B] to [16B], 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 cross reality devices (xR lenses), and lenses for head-mounted displays (HMD lenses). [18B] A cured product of the photocurable resin composition according to any one of [1B] to [17B]. [19B] An optical molded body comprising a cured product of the photocurable resin composition according to any one of [1B] to [18B]. [20B] The optical molded body according to [19B], wherein the optical molded body comprises a lens.[21B] The optical molded body according to [20B], wherein the lens comprises 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). [22B] The optical molded body according to any one of [19B] to [21B], wherein the maximum thickness portion is 20.0 mm or less. [23B] The optical molded body according to any one of [19B] to [23B], wherein the maximum thickness portion is 1.0 mm or more.

[0012] According to the first embodiment of the present invention, it is possible to provide a photocurable resin composition that can give an optical molded article having an improved balance of moldability and transparency.

[0013] According to the second embodiment of the present invention, it is possible to provide a photocurable resin composition that can reduce the occurrence of cracks in an optical molded body.

[0014] 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 in each 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.

[0015] <<First Embodiment>> Hereinafter, a photocurable resin composition and an optical molded body according to a first embodiment of the present invention will be described.

[0016] (Photocurable Resin Composition) The photocurable resin composition of the first embodiment (hereinafter also referred to simply as the "resin composition") contains a (meth)acrylate monomer (A) having an alicyclic skeleton (hereinafter also referred to simply as the "(meth)acrylate monomer (A)"), a (meth)acrylate polymer (B) having an alicyclic skeleton (hereinafter also referred to simply as the "(meth)acrylate polymer (B)"), and a photopolymerization initiator (C). The photocurable resin composition of the first embodiment has the above-described configuration, making it possible to obtain an optical molded body with an improved balance of moldability and transparency.

[0017] Although the reason for this is not entirely clear, the following reason is presumed. The photocurable resin composition of the first embodiment contains a (meth)acrylate polymer (B) having an alicyclic skeleton, which increases the viscosity of the photocurable resin composition. This is thought to reduce the fluidity of the photocurable resin composition during curing, thereby improving the moldability of the optical molded body. Furthermore, the photocurable resin composition of the first embodiment contains a (meth)acrylate monomer (A) having an alicyclic skeleton and a (meth)acrylate polymer (B) having an alicyclic skeleton that has optical properties similar to those of a polymer obtained by polymerizing the (meth)acrylate monomer (A), which is thought to reduce the transparency of the optical molded body obtained from the photocurable resin composition.

[0018] The properties of the photocurable resin composition are not particularly limited. However, from the viewpoint of being suitable for molding an optical molded body using an injection method or a casting 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 by a casting method.

[0019] Next, each component of the photocurable resin composition of the first embodiment will be described with specific examples. The photocurable resin composition of the first embodiment may be composed of a (meth)acrylate monomer (A), a (meth)acrylate polymer (B), and a photopolymerization initiator (C), or may contain components other than the (meth)acrylate monomer (A), the (meth)acrylate polymer (B), and the photopolymerization initiator (C). Examples of other components of the photocurable resin composition include a monomer component (G) other than the (meth)acrylate monomer (A), an antioxidant (D), a light stabilizer (E), and a chain transfer agent (F), which will be described later.

[0020] <(Meth)acrylate Monomer (A) Having an Alicyclic Skeleton> The (meth)acrylate monomer (A) is a compound having an alicyclic skeleton and 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.

[0021] From the viewpoint of improving the performance balance between the moldability and transparency of the optical molded body, the (meth)acrylate monomer (A) of the first embodiment has an alicyclic skeleton, preferably one or two or more skeletons selected from the group consisting of an adamantane skeleton, a norbornane skeleton, a dicyclopentadiene skeleton, an isobornyl skeleton, and a cyclohexane skeleton, and more preferably one or two or more skeletons selected from the group consisting of a dicyclopentadiene skeleton and a norbornane skeleton.

[0022] The (meth)acrylate monomer (A) of the first embodiment is preferably monofunctional or bifunctional or higher, more preferably monofunctional or bifunctional, from the viewpoint of further improving the performance balance between the moldability and transparency of the optical molded body.

[0023] From the viewpoint of further improving the performance balance between the moldability and transparency of the optical molded body, the (meth)acrylate monomer (A) in the first embodiment preferably includes one or more selected from the group consisting of a monofunctional (meth)acrylate monomer (A1) having an alicyclic skeleton (hereinafter also referred to simply as "(meth)acrylate monomer (A1)" as appropriate) and a difunctional or higher (meth)acrylate monomer (A2) having an alicyclic skeleton (hereinafter also referred to simply as "(meth)acrylate monomer (A2)" as appropriate), and more preferably includes one or more selected from the group consisting of a monofunctional (meth)acrylate monomer (A1) and a difunctional (meth)acrylate monomer (A2).

[0024] From the viewpoint of further improving the performance balance between the moldability and transparency of the optical molded body, the content of the (meth)acrylate monomer (A1) in the photocurable resin composition of the first embodiment is preferably 0 parts by mass or more and 100 parts by mass or less, more preferably 10 parts by mass or more and 100 parts by mass or less, even more preferably 20 parts by mass or more and 100 parts by mass or less, even more preferably 30 parts by mass or more and 100 parts by mass or less, and even more preferably 40 parts by mass or more and 100 parts by mass or less, when the content of the (meth)acrylate monomer (A) is taken as 100 parts by mass.

[0025] From the viewpoint of further improving the performance balance between the moldability and transparency of the optical molded body, the content of the (meth)acrylate monomer (A2) in the photocurable resin composition of the first embodiment is preferably 0 parts by mass or more and 100 parts by mass or less, more preferably 0 parts by mass or more and 90 parts by mass or less, even more preferably 0 parts by mass or more and 80 parts by mass or less, even more preferably 0 parts by mass or more and 70 parts by mass or less, and even more preferably 0 parts by mass or more and 60 parts by mass or less, when the content of the (meth)acrylate monomer (A) is taken as 100 parts by mass.

[0026] From the viewpoint of further improving the performance balance between the moldability and transparency of the optical molded body, the content of the (meth)acrylate monomer (A) in the photocurable resin composition of the first embodiment is preferably 1.0% by mass or more and 99% by mass or less, more preferably 10% by mass or more and 95% by mass or less, even more preferably 40% by mass or more and 90% by mass or less, even more preferably 50% by mass or more and 88% by mass or less, and even more preferably 60% by mass or more and 85% 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.

[0027] <Monofunctional (meth)acrylate monomer (A1) having an alicyclic skeleton> The (meth)acrylate monomer (A1) is a compound having an alicyclic skeleton and one (meth)acryloyl group. The (meth)acrylate monomer (A1) is preferably an alicyclic monofunctional (meth)acrylate monomer, and more preferably a monofunctional (meth)acrylate monomer having an alicyclic hydrocarbon structure in its molecular structure.

[0028] 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, from the viewpoint of improving heat resistance.

[0029] The alicyclic hydrocarbon structure may be a saturated hydrocarbon structure or an unsaturated hydrocarbon structure, but 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 monofunctional (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.

[0031] Examples of monocyclic hydrocarbon groups include groups having a cycloalkane structure such as a cyclohexylene group and a cyclohexyl group, and groups having a cycloalkene skeleton such as a cyclodecatrienediyl group and a cyclodecatriene group. Specific examples of polycyclic hydrocarbon groups include groups having a dicyclopentadiene skeleton such as a tricyclodecanediyl group, a dicyclopentanyl group, and a dicyclopentenyl group, groups having a norbornane skeleton such as a norbornanediyl group, an isobornanediyl group, a norbornyl group, and groups having an adamantane skeleton such as an adamantanediyl group and an adamantyl group.

[0032] Examples of the (meth)acrylate monomer (A1) of the first embodiment include isobornyl (meth)acrylate, dicyclopentanyl (meth)acrylate, 3,3,5-trimethylcyclohexyl (meth)acrylate, 4-tert-butylcyclohexyl (meth)acrylate, dicyclopentenyl (meth)acrylate, dicyclopentenyloxyethyl (meth)acrylate, cyclohexyl (meth)acrylate, 2-methacryloyloxy-2-methyladamantane, and 2-methacryloyloxy-2-ethyladamantane.

[0033] The (meth)acrylate monomer (A1) of the first embodiment preferably contains one or more monomers selected from the group consisting of dicyclopentanyl methacrylate, dicyclopentanyl acrylate, and isobornyl methacrylate, from the viewpoint of further improving the performance balance between the moldability and transparency of the optical molded body.

[0034] <Difunctional or Higher Functional (Meth)acrylate Monomer (A2) Having an Alicyclic Skeleton> The (meth)acrylate monomer (A2) is a compound having an alicyclic skeleton and two or more (meth)acryloyl groups. The (meth)acrylate monomer (A2) is preferably an alicyclic bifunctional (meth)acrylate monomer, and more preferably a bifunctional (meth)acrylate monomer having an alicyclic hydrocarbon structure in its molecular structure.

[0035] 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, from the viewpoint of improving heat resistance.

[0036] The alicyclic hydrocarbon structure may be a saturated hydrocarbon structure or an unsaturated hydrocarbon structure, but from the viewpoint of improving heat resistance, the alicyclic hydrocarbon structure is preferably a saturated hydrocarbon structure.

[0037] 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.

[0038] Examples of monocyclic hydrocarbon groups include groups having a cycloalkane structure such as a cyclohexylene group and a cyclohexyl group, and groups having a cycloalkene skeleton such as a cyclodecatrienediyl group and a cyclodecatriene group. Specific examples of polycyclic hydrocarbon groups include groups having a dicyclopentadiene skeleton such as a tricyclodecanediyl group, a dicyclopentanyl group, and a dicyclopentenyl group, groups having a norbornane skeleton such as a norbornanediyl group, an isobornanediyl group, a norbornyl group, and groups having an adamantane skeleton such as an adamantanediyl group and an adamantyl group.

[0039] The alicyclic hydrocarbon group in the alicyclic bifunctional (meth)acrylate monomer is preferably a group having a dicyclopentadiene skeleton, from the viewpoint of further improving the performance balance between the moldability and transparency of the optical molded body. Also, the alicyclic bifunctional (meth)acrylate monomer preferably contains tricyclodecane dimethanol di(meth)acrylate, from the viewpoint of further improving the performance balance between the moldability and transparency of the optical molded body.

[0040] <(Meth)acrylate Polymer (B) Having an Alicyclic Skeleton> The (meth)acrylate polymer (B) is a polymer obtained by polymerizing a monomer component containing a compound having an alicyclic skeleton and a (meth)acryloyl group.

[0041] For example, a (meth)acrylate monomer (A) can be used to synthesize the (meth)acrylate polymer (B). For example, a thermal polymerization initiator or a photopolymerization initiator (C) can be used to synthesize the (meth)acrylate polymer (B). Specifically, the method described in the examples can be used to synthesize the (meth)acrylate polymer (B) of the first embodiment.

[0042] The (meth)acrylate polymer (B) of the first embodiment has an alicyclic skeleton from the viewpoint of improving the performance balance between the moldability and transparency of the optical molded body. From the viewpoint of improving the performance balance between the moldability and transparency of the optical molded body, the (meth)acrylate polymer (B) of the first embodiment preferably has one or more skeletons selected from the group consisting of an adamantane skeleton, a norbornane skeleton, a dicyclopentadiene skeleton, an isobornyl skeleton, and a cyclohexane skeleton, and more preferably has one or more skeletons selected from the group consisting of a dicyclopentadiene skeleton and a norbornane skeleton.

[0043] From the viewpoint of further improving the performance balance between the moldability and transparency of the optical molded body, the (meth)acrylate polymer (B) of the first embodiment preferably contains a repeating unit derived from a (meth)acrylate monomer (A) having an alicyclic skeleton, more preferably contains a repeating unit derived from a (meth)acrylate monomer (A) having one or more skeletons selected from the group consisting of an adamantane skeleton, a norbornane skeleton, a dicyclopentadiene skeleton, an isobornyl skeleton, and a cyclohexane skeleton, and even more preferably contains a repeating unit derived from one or more (meth)acrylate monomers (A) selected from the group consisting of dicyclopentanyl (meth)acrylate and isobornyl (meth)acrylate.

[0044] From the viewpoint of further improving the performance balance between the moldability and transparency of the optical molded body, the (meth)acrylate polymer (B) of the first embodiment preferably contains one or two or more repeating units selected from the group consisting of repeating units derived from a monofunctional (meth)acrylate monomer (A1) and repeating units derived from a difunctional or higher functional (meth)acrylate monomer (A2), more preferably contains one or two or more repeating units selected from the group consisting of repeating units derived from a monofunctional (meth)acrylate monomer (A1) and repeating units derived from a difunctional (meth)acrylate monomer (A2), and even more preferably contains a repeating unit derived from a monofunctional (meth)acrylate monomer (A1).

[0045] From the viewpoint of further improving the performance balance between moldability and transparency of the optical molded body, the weight average molecular weight Mw of the (meth)acrylate polymer (B) of the first embodiment is preferably 3,000 or more and 5,000,000 or less, more preferably 3,000 or more and 4,500,000 or less, even more preferably 3,000 or more and 4,000,000 or less, even more preferably 3,000 or more and 3,500,000 or less, even more preferably 3,000 or more and 3,000,000 or less, even more preferably 3,000 or more and 2,500,000 or less, even more preferably 3,000 or more and 2,000,000 or less, and even more preferably 3,000 or more. The weight average molecular weight Mw of the (meth)acrylate polymer (B) of the first embodiment is preferably 1,500,000 or less, more preferably 3,000 or more and 1,000,000 or less, even more preferably 3,000 or more and 500,000 or less, even more preferably 3,000 or more and 250,000 or less, even more preferably 4,000 or more and 250,000 or less, even more preferably 5,000 or more and 250,000 or less, even more preferably 7,500 or more and 200,000 or less, even more preferably 10,000 or more and 180,000 or less, even more preferably 20,000 or more and 150,000 or less, even more preferably 30,000 or more and 120,000 or less, even more preferably 50,000 or more and 100,000 or less.

[0046] In the (meth)acrylate polymer (B) of the first embodiment, the repeating units derived from the (meth)acrylate monomer (A) having an alicyclic skeleton are preferably 10 mol% or more and 100 mol% or less, more preferably 50 mol% or more and 100 mol% or less, even more preferably 85 mol% or more and 100 mol% or less, even more preferably 90 mol% or more and 100 mol% or less, and even more preferably 95 mol% or more and 100 mol% or less, when the total number of moles of repeating units in the (meth)acrylate polymer (B) is taken as 100 mol%, from the viewpoint of further improving the performance balance between the moldability and transparency of the optical molded body.

[0047] From the viewpoint of further improving the performance balance between the moldability and transparency of the optical molded body, the content of the (meth)acrylate polymer (B) in the photocurable resin composition of the first embodiment is preferably 0.5 parts by mass or more and 90 parts by mass or less, more preferably 1 part by mass or more and 90 parts by mass or less, more preferably 2 parts by mass or more and 90 parts by mass or less, more preferably 3 parts by mass or more and 90 parts by mass or less, more preferably 4 parts by mass or more and 90 parts by mass or less, even more preferably 5 parts by mass or more and 80 parts by mass or less, even more preferably 10 parts by mass or more and 75 parts by mass or less, even more preferably 12 parts by mass or more and 70 parts by mass or less, and even more preferably 15 parts by mass or more and 65 parts by mass or less, when the content of the (meth)acrylate monomer (A) is taken as 100 parts by mass.

[0048] From the viewpoint of further improving the performance balance between the moldability and transparency of the optical molded body, the content of the (meth)acrylate polymer (B) in the photocurable resin composition of the first embodiment is preferably 1% by mass or more and 90% by mass or less, more preferably 3% by mass or more and 85% by mass or less, even more preferably 5% by mass or more and 75% by mass or less, even more preferably 7% by mass or more and 65% by mass or less, even more preferably 10% by mass or more and 55% by mass or less, even more preferably 12% by mass or more and 45% by mass or less, and even more preferably 15% by mass or more and 35% 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.

[0049] <Photopolymerization initiator (C)> 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 when irradiated 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.

[0050] Examples of the photopolymerization initiator (C) include benzophenone, Michler's ketone (4,4'-bis(dimethylamino)benzophenone), 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, and 2,2-diethoxyacetophenone. benzophenone, 2,2-dimethoxy-2-phenylacetophenone, camphorquinone, benzanthrone, ethyl 4-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 azine, 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-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-mol 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,Examples of such oxime include 6-trimethylbenzoyldiphenylphosphine oxide, 2,4,6-trimethylbenzoyldiphenylphosphinic acid ester, 1-[4-(phenylthio)phenyl]-1,2-octanedione-2-(O-benzoyloxime), and 1-[9-ethyl-6-(2-methylbenzoyl)-9H-carbazol-3-yl]-ethanone-1-(O-acetyloxime).

[0051] From the viewpoint of further improving the balance of the moldability and transparency of the optical molded body, the photopolymerization initiator (C) preferably contains a hydroxyphenyl ketone initiator, and more preferably contains 1-hydroxycyclohexyl phenyl ketone.

[0052] From the viewpoint of further improving the performance balance between the moldability and transparency of the optical molded body, the content of the photopolymerization initiator (C) in the photocurable resin composition of the first embodiment is preferably 0.1 parts by mass or more and 10 parts by mass or less, more preferably 0.5 parts by mass or more and 8.5 parts by mass or less, even more preferably 1 part by mass or more and 8 parts by mass or less, even more preferably 1.5 parts by mass or more and 7.5 parts by mass or less, and even more preferably 2 parts by mass or more and 7 parts by mass or less, when the content of the (meth)acrylate monomer (A) is taken as 100 parts by mass.

[0053] From the viewpoint of further improving the performance balance between the moldability and transparency of the optical molded body, the content of the photopolymerization initiator (C) in the photocurable resin composition of the first embodiment is preferably 0.1% by mass or more and 10% by mass or less, more preferably 1% by mass or more and 8% by mass or less, even more preferably 2% by mass or more and 6% by mass or less, even more preferably 2.5% by mass or more and 5% by mass or less, and even more preferably 3% by mass or more and 4% 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.

[0054] From the viewpoint of further improving the performance balance between the moldability and transparency of the optical molded body, the total content of the (meth)acrylate monomer (A), the (meth)acrylate polymer (B), and the photopolymerization initiator (C) in the photocurable resin composition of the first embodiment is preferably 50% by mass or more and 100% by mass or less, more preferably 60% by mass or more and 100% by mass or less, even more preferably 70% by mass or more and 100% by mass or less, even more preferably 75% by mass or more and 100% by mass or less, and even more preferably 78% by mass or more and 100% 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.

[0055] <Monomer component (G) other than (meth)acrylate monomer (A)> From the viewpoint of improving the brittleness of the optical molded body, the photocurable resin composition of the first embodiment preferably further includes a monomer component (G) other than the (meth)acrylate monomer (A) (hereinafter also simply referred to as "monomer (G)"), and more preferably further includes a monofunctional or di- or higher functional (meth)acrylate monomer (excluding the (meth)acrylate monomer (A)). The photocurable resin composition of the first embodiment further preferably includes a di- or higher functional (meth)acrylate monomer (excluding the (meth)acrylate monomer (A2)), still more preferably includes a linear difunctional (meth)acrylate monomer, still more preferably includes 1,12-dodecanediol (meth)acrylate, and still more preferably includes 1,12-dodecanediol dimethacrylate.

[0056] The linear bifunctional (meth)acrylate monomer is a compound having a linear structure and two (meth)acryloyl groups. The linear structure preferably contains a divalent linear hydrocarbon group from the viewpoint of further improving crack resistance during molding of the optical molded body. The number of carbon atoms in the divalent linear hydrocarbon group is preferably 1 or more, more preferably 2 or more, and even 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, the number of carbon atoms in the divalent linear hydrocarbon group is preferably 20 or less, more preferably 14 or less, from the viewpoint of improving heat resistance.

[0057] Examples of linear bifunctional (meth)acrylate monomers include di(meth)acrylates of alkanediols, such as 1,6-hexanediol di(meth)acrylate, 1,9-nonanediol di(meth)acrylate, 1,10-decanediol di(meth)acrylate, 1,12-dodecanediol di(meth)acrylate, ethylene glycol di(meth)acrylate, triethylene glycol di(meth)acrylate, polyethylene glycol di(meth)acrylate, 1,3-butanediol di(meth)acrylate, and 1,4-butanediol di(meth)acrylate.

[0058] From the viewpoint of improving the brittleness of the optical molded body, the content of the monomer (G) in the photocurable resin composition of the first embodiment is preferably 0 parts by mass or more and 50 parts by mass or less, more preferably 5 parts by mass or more and 45 parts by mass or less, even more preferably 10 parts by mass or more and 40 parts by mass or less, even more preferably 15 parts by mass or more and 35 parts by mass or less, and even more preferably 20 parts by mass or more and 30 parts by mass or less, when the content of the (meth)acrylate monomer (A) is taken as 100 parts by mass.

[0059] From the viewpoint of improving the brittleness of the optical molded body, the content of monomer (G) in the photocurable resin composition of the first embodiment is preferably 0% by mass or more and 30% by mass or less, more preferably 5% by mass or more and 25% by mass or less, even more preferably 10% by mass or more and 20% by mass or less, even more preferably 11% by mass or more and 19% by mass or less, and even more preferably 12% by mass or more and 18% 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.

[0060] <Antioxidant (D)> The photocurable resin composition of the first embodiment may further contain an antioxidant (D). The type of antioxidant (D) is not particularly limited, and known antioxidants can be used. Examples of the antioxidant (D) include phenol-based antioxidants, phosphorus-based antioxidants, sulfur-based antioxidants, hindered amine-based antioxidants, and thioether-based antioxidants.

[0061] Examples of phenolic antioxidants include 2,6-di-t-butylhydroxytoluene and pentaerythritol-tetrakis[3-(3',5'-di-tert-butyl-4'-hydroxyphenyl)propionate].

[0062] Examples of phosphorus-based antioxidants include phosphines such as trialkylphosphine and triarylphosphine, trialkyl phosphites, and triaryl phosphites.

[0063] 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), and 3,9-bis(2-dodecylthioethyl)-2,4,8,10-tetraoxaspiro[5,5]undecane.

[0064] 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.

[0065] 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].

[0066] The content of the antioxidant (D) in the photocurable resin composition of the first embodiment is preferably 0.01 parts by mass or more and 10 parts by mass or less, more preferably 0.05 parts by mass or more and 5 parts by mass or less, even more preferably 0.1 parts by mass or more and 3 parts by mass or less, even more preferably 0.2 parts by mass or more and 2 parts by mass or less, and even more preferably 0.5 parts by mass or more and 1.5 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 further improving the performance balance between the moldability and transparency of the optical molded body.

[0067] The content of the antioxidant (D) in the photocurable resin composition of the first embodiment is preferably 0.01% by mass or more and 5% by mass or less, more preferably 0.05% by mass or more and 4% by mass or less, even more preferably 0.1% by mass or more and 3% by mass or less, even more preferably 0.5% by mass or more and 2% by mass or less, and even more preferably 0.7% by mass or more and 1% by mass or less, from the viewpoint of further improving the performance balance between the moldability and transparency of the optical molded body, 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.

[0068] <Light Stabilizer (E)> The photocurable resin composition of the first embodiment may further contain a light stabilizer (E). The type of light stabilizer (E) is not particularly limited, and known light stabilizers can be used. The light stabilizer (E) can improve the coloration resistance of the photocurable resin composition. From the viewpoint of further improving coloration resistance, the light stabilizer (E) preferably contains a hindered amine-based light stabilizer.

[0069] Examples of hindered amine light stabilizers include bis(1-octyloxy-2,2,6,6-tetramethyl-4-piperidyl)sebacic acid, 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 reaction product of 70% by mass 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 methyl-1,2,2,6,6-pentamethyl-4-piperidyl tetrakis(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.

[0070] The content of the light stabilizer (E) in the photocurable resin composition of the first embodiment is preferably 0.01 parts by mass or more and 10 parts by mass or less, more preferably 0.05 parts by mass or more and 5 parts by mass or less, even more preferably 0.1 parts by mass or more and 3 parts by mass or less, even more preferably 0.1 parts by mass or more and 2 parts by mass or less, and even more preferably 0.1 parts by mass or more and 1.5 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 further improving the performance balance between the moldability and transparency of the optical molded body.

[0071] The content of the light stabilizer (E) in the photocurable resin composition of the first embodiment is preferably 0.01% by mass or more and 5% by mass or less, more preferably 0.05% by mass or more and 4% by mass or less, even more preferably 0.1% by mass or more and 3% by mass or less, even more preferably 0.5% by mass or more and 2% by mass or less, and even more preferably 0.7% by mass or more and 1% by mass or less, from the viewpoint of further improving the performance balance between the moldability and transparency of the optical molded body, 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.

[0072] <Chain Transfer Agent (F)> The photocurable resin composition of the first embodiment may further contain a chain transfer agent (F). The type of chain transfer agent (F) is not particularly limited, and a known chain transfer agent can be used. When the photocurable resin composition contains the chain transfer agent (F), it is possible to adjust the molecular weight of the (meth)acrylate monomer (A) after radical polymerization.

[0073] Examples of the chain transfer agent (F) include mercaptans, secondary thiols, and primary thiols.

[0074] Examples of mercaptans include t-dodecyl mercaptan and n-dodecyl mercaptan.

[0075] Examples of secondary thiols include pentaerythritol tetrakis(3-mercaptobutyrate), 1,4-bis(3-mercaptobutyryloxy)butane, 1,3,5-tris(2-(3-sulfanylbutanoyloxy)ethyl)-1,3,5-triazinane-2,4,6-trione, and trimethylolpropane tris(3-mercaptobutyrate).

[0076] Examples of primary thiols include 2,2-bis[[(3-mercaptopropionyl)oxy]methyl]trimethylenebis[3-mercaptopropionate], 3-mercaptopropionic acid ester of dipentaerythritol, tris-[(3-mercaptopropionyloxy)-ethyl]-isocyanurate, tetraethylene glycol bis(3-mercaptopropionate), 2-ethylhexyl-3-mercaptopropionate, and methoxybutyl-β-mercaptopropionate. Furthermore, examples of primary thiols include 2-ethyl-2-{[(3-sulfanylpropanoyl)oxy]methyl}propane-1,3-diyl bis(3-sulfanylpropanoate), 2-ethyl-2-[({3-[(3-sulfanylpropanoyl)sulfanyl]propanoyl}oxy)methyl]propane-1,3-diyl bis(3-sulfanylpropanoate), 2-ethyl-2-(hydroxymethyl)propane-1,3-diyl bis(3-sulfanylpropanoate), and mixtures thereof.

[0077] From the viewpoint of further improving the performance balance between the moldability and transparency of the optical molded body, the chain transfer agent (F) preferably contains one or more selected from the group consisting of mercaptans and secondary thiols, more preferably contains one or more selected from the group consisting of t-dodecyl mercaptan, n-dodecyl mercaptan, and pentaerythritol tetrakis(3-mercaptobutyrate), even more preferably contains one or more selected from the group consisting of t-dodecyl mercaptan and pentaerythritol tetrakis(3-mercaptobutyrate), and even more preferably contains t-dodecyl mercaptan.

[0078] The content of the chain transfer agent (F) in the photocurable resin composition of the first embodiment is preferably 0.1 parts by mass or more and 10 parts by mass or less, more preferably 1 part by mass or more and 9 parts by mass or less, even more preferably 2 parts by mass or more and 8 parts by mass or less, even more preferably 3 parts by mass or more and 7 parts by mass or less, and even more preferably 4 parts by mass or more and 6 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 further improving the performance balance between the moldability and transparency of the optical molded body.

[0079] The content of the chain transfer agent (F) in the photocurable resin composition of the first embodiment is preferably 0.1% by mass or more and 10% by mass or less, more preferably 1% by mass or more and 8% by mass or less, even more preferably 2% by mass or more and 6% by mass or less, and even more preferably 3% by mass or more and 5% by mass or less, from the viewpoint of further improving the performance balance between the moldability and transparency of the optical molded body, 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.

[0080] <Other Components> The photocurable resin composition of the first embodiment may contain components other than the (meth)acrylate monomer (A), the (meth)acrylate polymer (B), the photopolymerization initiator (C), the monomer component (G) other than the (meth)acrylate monomer (A) (monomer (G)), the antioxidant (D), the light stabilizer (E), and the chain transfer agent (F). Examples of the other components include 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.

[0081] <Method for producing photocurable resin composition> The photocurable resin composition of the first embodiment can be obtained by mixing the (meth)acrylate monomer (A), the (meth)acrylate polymer (B), and the photopolymerization initiator (C), and, if necessary, the monomer (G), the antioxidant (D), the light stabilizer (E), the chain transfer agent (F), and other components, by a conventionally known method. Note that the method for producing the photocurable resin composition, more specifically, the method described in the examples, can be adopted.

[0082] <Physical Properties of Photocurable Resin Composition> Next, the physical properties of the photocurable resin composition will be described.

[0083] <Viscosity> The viscosity of the photocurable resin composition of the first embodiment is described below, measured using an E-type viscometer at a temperature of 25°C and a rotation speed of 2.5 rpm. More specifically, the method described in the examples can be used to measure the viscosity of the photocurable resin composition. In the first embodiment, the viscosity of the photocurable resin composition is preferably 110 mPa·s or more and 5000 mPa·s or less, more preferably 120 mPa·s or more and 3500 mPa·s or less, even more preferably 140 mPa·s or more and 1900 mPa·s or less, even more preferably 170 mPa·s or more and 1400 mPa·s or less, even more preferably 220 mPa·s or more and 900 mPa·s or less, and even more preferably 250 mPa·s or more and 800 mPa·s or less, from the viewpoint of further improving the performance balance between the moldability and transparency of the optical molded body.

[0084] <Haze Value> For the photocurable resin composition of the first embodiment, the haze value of a cured film prepared according to the following <Cured Film Preparation Conditions>, measured in accordance with JIS K 7136:2000, at a thickness of 3.0 mm, will be described. From the viewpoint of further improving the performance balance of moldability and transparency of the optical molded body, the haze value is preferably less than 1.0%, more preferably 0.90% or less, even more preferably 0.80% or less, even more preferably 0.70% or less, even more preferably 0.65% or less, even more preferably 0.60% or less, even more preferably 0.55% or less, even more preferably 0.50% or less, even more preferably 0.45% or less, even more preferably 0.40% or less, even more preferably 0.35% or less, even more preferably 0.30% or less, and even more preferably 0.25% or less. The lower limit of the haze value is not particularly limited, but may be, for example, 0.01% or more, 0.05% or more, or 0.1% or more.

[0085] <Conditions for preparing a cured film> 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 was placed on a 0.7 mm thick, 50 mm x 50 mm alkali-free glass. Next, the circular hole was filled with a photocurable resin composition, and then a 0.7 mm thick, 50 mm x 50 mm alkali-free glass was placed on top of it. Next, this was placed on a SUS lab jack to adjust the height. Next, the photocurable resin composition was irradiated with LED light having a wavelength of 405 nm at 810 mW for 3 minutes from above the alkali-free glass, and then turned over and irradiated with LED light having a wavelength of 405 nm at 810 mW for 3 minutes. After irradiating with LED light, the glass was allowed to cool at 23°C for 30 minutes, and the cured product of the photocurable resin composition was released from the alkali-free glass and silicone sheet to obtain a cured film. More specifically, the conditions for producing a cured film of the photocurable resin composition of the first embodiment may be the conditions described in the Examples. Also, more specifically, the method for measuring the haze value of the photocurable resin composition may be the method described in the Examples.

[0086] <Uses of Photocurable Resin Composition> Next, uses of the photocurable resin composition will be described.

[0087] The photocurable resin composition of the first embodiment can improve the balance of moldability and transparency of an optical molded body molded from the photocurable resin composition, and therefore can be used in methods for molding optical molded bodies, such as injection molding, compression molding, injection compression molding, extrusion molding, solution casting, and casting. In particular, the photocurable resin composition of the first embodiment can be used in casting.

[0088] The photocurable resin composition of the first embodiment can improve the performance balance between moldability and transparency of an optical molded body molded from the photocurable resin composition, and therefore the use of the photocurable resin composition is not particularly limited, and the composition can be used for a variety of purposes.

[0089] The photocurable resin composition of the first embodiment can be preferably used for, for example, a lens, which may include, 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.

[0090] The photocurable resin composition of the first 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).

[0091] The photocurable resin composition of the first 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.

[0092] The photocurable resin composition of the first 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).

[0093] (Cured Product) The cured product of the first embodiment is a cured product of the photocurable resin composition of the first embodiment. The cured product of the first embodiment can be produced, for example, by irradiating the photocurable resin composition of the first embodiment with LED light to cure it. Note that, as more specific production conditions for the cured product of the first embodiment, for example, the conditions described in the examples can be adopted.

[0094] (Optical Molded Body) The optical molded body of the first embodiment includes a cured product of the photocurable resin composition of the first embodiment. The optical molded body of the first embodiment can be manufactured using the photocurable resin composition of the first embodiment. The optical molded body can be manufactured from the photocurable resin composition of the first embodiment by any method, such as injection molding, compression molding, injection compression molding, extrusion molding, solution casting, or casting.

[0095] The optical molded body of the first 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.

[0096] The lens of the first 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).

[0097] The optical molded body of the first 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.

[0098] The cover display of the first 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).

[0099] 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.

[0100] For example, in the optical molded body of the first embodiment, the maximum thickness portion is preferably 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.

[0101] The photocurable resin composition of the first embodiment can improve the balance of moldability and transparency of an optical molded body, and therefore can be applied to optical molded bodies having a thickness of 1.0 mm or more.

[0102] (Optical Device) The optical device of the first embodiment includes the optical molded body of the first embodiment. The type of the optical device of the first embodiment is not particularly limited. Examples of the optical device of the first 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).

[0103] Although the first embodiment of the present invention has been described above, these are merely examples of the first embodiment of the present invention, and various other configurations may be adopted. Furthermore, the first embodiment of the present invention is not limited to the above-described embodiment, and modifications and improvements that do not impair the effects of the first embodiment of the present invention are included in the first embodiment of the present invention.

[0104] Second Embodiment Hereinafter, a method for producing an optical molded body according to a second embodiment of the present invention will be described.

[0105] (Photocurable Resin Composition) The photocurable resin composition of the second embodiment (hereinafter also referred to simply as "resin composition") contains a (meth)acrylate monomer (A) having an alicyclic skeleton (hereinafter also referred to simply as "(meth)acrylate monomer (A)"), a (meth)acrylate polymer (B) having an alicyclic skeleton (hereinafter also referred to simply as "(meth)acrylate polymer (B)"), and a photopolymerization initiator (C). The photocurable resin composition of the second embodiment has a humidity swelling ratio α1 of 0.35% or less, measured according to the following <humidity-controlled thermomechanical analysis (humidity-controlled TMA)>, in a cured film produced according to the following <cured film production conditions>. <Cured film production conditions> A 100 μm thick, 100 mm x 100 mm PET film and a 500 μm thick, 100 mm x 100 mm silicone sheet (material: silicone rubber, hardness: 50 degrees) with a 50 mm diameter circular hole were placed on a 2.0 mm thick, 100 mm x 100 mm non-alkali glass sheet in this order, and the circular hole was filled with a photocurable resin composition. Then, a 100 μm thick, 100 mm x 100 mm PET film and a 2.0 mm thick, 100 mm x 100 mm non-alkali glass sheet were placed on top of the 100 μm thick, 100 mm x 100 mm PET film and a 2.0 mm thick, 100 mm x 100 mm non-alkali glass sheet. Two pieces of alkali-free glass were further placed on top of each other in this order, and these were then placed on an SUS lab jack to adjust the height. One piece of alkali-free glass was irradiated with LED light having a wavelength of 405 nm at 810 mW for 3 minutes onto the photocurable resin composition, and the glass was then turned over and irradiated with LED light having a wavelength of 405 nm at 810 mW for 3 minutes. The glass was then allowed to cool at 23°C for 30 minutes, and the cured product of the photocurable resin composition was then released from the alkali-free glass, PET film, and silicone sheet to obtain a cured film.<Humidity-Conditioned Thermomechanical Analysis (Humidity-Conditioned TMA)> The cured film was cut into a strip having a width of 5 mm and a length of 15 mm to prepare a test piece. The test piece was subjected to humidity-conditioned thermomechanical analysis (humidity-conditioned TMA) in a tensile mode with a load of 5 gf, a chuck distance of 10 mm, in a nitrogen atmosphere, and at a constant temperature of 65°C. The following steps were successively performed: maintaining the test piece at a humidity of 0% RH for 30 minutes, increasing the humidity from 0% RH to 90% RH at a humidity increase rate of 5% RH / min (humidity increase step), maintaining the test piece at a humidity of 90% RH for 150 minutes, decreasing the humidity from 90% RH to 0% RH at a humidity decrease rate of 5% RH / min (humidity decrease step), and maintaining the test piece at a humidity of 0% RH for 55 minutes. The humidity swelling ratio in the humidity increase step was designated as the humidity swelling ratio α1. The photocurable resin composition of the second embodiment has the above-described configuration, and therefore can reduce the occurrence of cracks in the optical molded body obtained from the photocurable resin composition of the second embodiment.

[0106] Although the reason for this is not entirely clear, the following reason is presumed. The photocurable resin composition of the second embodiment contains a (meth)acrylate polymer (B) having an alicyclic skeleton, thereby improving the toughness of the optical molded body obtained from the photocurable resin composition. Furthermore, since the humidity swelling ratio α1 measured according to the above method is 0.35% or less, the shape change of the optical molded body obtained from the photocurable resin composition upon moisture absorption can be reduced. As a result, it is believed that the occurrence of cracks in the optical molded body can be reduced. Furthermore, the photocurable resin composition of the second embodiment contains a (meth)acrylate monomer (A) having an alicyclic skeleton and a (meth)acrylate polymer (B) having an alicyclic skeleton whose optical properties are similar to those of the polymer obtained by polymerizing the (meth)acrylate monomer (A), thereby making it less likely that the transparency of the optical molded body obtained from the photocurable resin composition will decrease.

[0107] The properties of the photocurable resin composition are not particularly limited. However, from the viewpoint of being suitable for molding an optical molded body using an injection method or a casting 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 by a casting method.

[0108] Next, each component of the photocurable resin composition of the second embodiment will be described with specific examples. The photocurable resin composition of the second embodiment may be composed of a (meth)acrylate monomer (A), a (meth)acrylate polymer (B), and a photopolymerization initiator (C), or may contain components other than the (meth)acrylate monomer (A), the (meth)acrylate polymer (B), and the photopolymerization initiator (C). Examples of other components of the photocurable resin composition include a monomer component (G) other than the (meth)acrylate monomer (A), an antioxidant (D), a light stabilizer (E), and a chain transfer agent (F), which will be described later.

[0109] <(Meth)acrylate Monomer (A) Having an Alicyclic Skeleton> The (meth)acrylate monomer (A) is a compound having an alicyclic skeleton and 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.

[0110] From the viewpoint of being able to reduce the occurrence of cracks in the optical molded body and being able to improve the performance balance between the moldability and transparency of the optical molded body, the (meth)acrylate monomer (A) of the second embodiment has an alicyclic skeleton, and preferably has one or two or more skeletons selected from the group consisting of an adamantane skeleton, a norbornane skeleton, a dicyclopentadiene skeleton, an isobornyl skeleton, and a cyclohexane skeleton, more preferably has one or two or more skeletons selected from the group consisting of a dicyclopentadiene skeleton and a norbornane skeleton, and even more preferably has a dicyclopentadiene skeleton.

[0111] The (meth)acrylate monomer (A) of the second embodiment is preferably monofunctional or di- or more functional, more preferably monofunctional or difunctional, and even more preferably monofunctional, from the viewpoint of further reducing the occurrence of cracks in the optical molded body.

[0112] From the viewpoint of further reducing the occurrence of cracks in the optical molded body and improving the performance balance between the moldability and transparency of the optical molded body, the (meth)acrylate monomer (A) in the second embodiment preferably includes one or more selected from the group consisting of a monofunctional (meth)acrylate monomer (A1) having an alicyclic skeleton (hereinafter also referred to simply as "(meth)acrylate monomer (A1)") and a di- or higher functional (meth)acrylate monomer (A2) having an alicyclic skeleton (hereinafter also referred to simply as "(meth)acrylate monomer (A2)"), more preferably includes one or more selected from the group consisting of a monofunctional (meth)acrylate monomer (A1) and a difunctional (meth)acrylate monomer (A2), and even more preferably includes a monofunctional (meth)acrylate monomer (A1).

[0113] From the viewpoint of further improving the performance balance between the moldability and transparency of the optical molded body, the content of the (meth)acrylate monomer (A1) in the photocurable resin composition of the second embodiment is preferably 50 parts by mass or more and 100 parts by mass or less, 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 100 parts by mass or less, and even more preferably 80 parts by mass or more and 100 parts by mass or less, when the content of the (meth)acrylate monomer (A) is taken as 100 parts by mass.

[0114] From the viewpoint of further improving the performance balance between the moldability and transparency of the optical molded body, the content of the (meth)acrylate monomer (A2) in the photocurable resin composition of the second embodiment is preferably 0 parts by mass or more and 50 parts by mass or less, more preferably 0 parts by mass or more and 40 parts by mass or less, even more preferably 0 parts by mass or more and 30 parts by mass or less, even more preferably 0 parts by mass or more and 25 parts by mass or less, and even more preferably 0 parts by mass or more and 20 parts by mass or less, when the content of the (meth)acrylate monomer (A) is taken as 100 parts by mass.

[0115] From the viewpoint of further reducing the occurrence of cracks in the optical molded body, the content of the (meth)acrylate monomer (A) in the photocurable resin composition of the second embodiment is preferably 10% by mass or more and 99% by mass or less, more preferably 20% by mass or more and 90% by mass or less, even more preferably 30% by mass or more and 80% by mass or less, even more preferably 40% by mass or more and 70% by mass or less, and even more preferably 50% by mass or more and 65% 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.

[0116] <Monofunctional (meth)acrylate monomer (A1) having an alicyclic skeleton> The (meth)acrylate monomer (A1) is a compound having an alicyclic skeleton and one (meth)acryloyl group. The (meth)acrylate monomer (A1) is preferably an alicyclic monofunctional (meth)acrylate monomer, and more preferably a monofunctional (meth)acrylate monomer having an alicyclic hydrocarbon structure in its molecular structure.

[0117] 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, from the viewpoint of improving heat resistance.

[0118] The alicyclic hydrocarbon structure may be a saturated hydrocarbon structure or an unsaturated hydrocarbon structure, but from the viewpoint of improving heat resistance, the alicyclic hydrocarbon structure is preferably a saturated hydrocarbon structure.

[0119] 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 monofunctional (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.

[0120] Examples of monocyclic hydrocarbon groups include groups having a cycloalkane structure such as a cyclohexylene group and a cyclohexyl group, and groups having a cycloalkene skeleton such as a cyclodecatrienediyl group and a cyclodecatriene group. Specific examples of polycyclic hydrocarbon groups include groups having a dicyclopentadiene skeleton such as a tricyclodecanediyl group, a dicyclopentanyl group, and a dicyclopentenyl group, groups having a norbornane skeleton such as a norbornanediyl group, an isobornanediyl group, a norbornyl group, and groups having an adamantane skeleton such as an adamantanediyl group and an adamantyl group.

[0121] Examples of the (meth)acrylate monomer (A1) according to the second embodiment include isobornyl (meth)acrylate, dicyclopentanyl (meth)acrylate, 3,3,5-trimethylcyclohexyl (meth)acrylate, 4-tertiarybutylcyclohexyl (meth)acrylate, dicyclopentenyl (meth)acrylate, dicyclopentenyloxyethyl (meth)acrylate, cyclohexyl (meth)acrylate, 2-methacryloyloxy-2-methyladamantane, and 2-methacryloyloxy-2-ethyladamantane.

[0122] The (meth)acrylate monomer (A1) of the second embodiment preferably contains one or more selected from the group consisting of dicyclopentanyl (meth)acrylate and isobornyl (meth)acrylate, more preferably contains dicyclopentanyl (meth)acrylate, and even more preferably contains dicyclopentanyl methacrylate, from the viewpoint of being able to further reduce the occurrence of cracks in the optical molded body and being able to improve the performance balance between the moldability and transparency of the optical molded body.

[0123] <Difunctional or Higher Functional (Meth)acrylate Monomer (A2) Having an Alicyclic Skeleton> The (meth)acrylate monomer (A2) is a compound having an alicyclic skeleton and two or more (meth)acryloyl groups. The (meth)acrylate monomer (A2) is preferably an alicyclic bifunctional (meth)acrylate monomer, and more preferably a bifunctional (meth)acrylate monomer having an alicyclic hydrocarbon structure in its molecular structure.

[0124] 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, from the viewpoint of improving heat resistance.

[0125] The alicyclic hydrocarbon structure may be a saturated hydrocarbon structure or an unsaturated hydrocarbon structure, but from the viewpoint of improving heat resistance, the alicyclic hydrocarbon structure is preferably a saturated hydrocarbon structure.

[0126] 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.

[0127] Examples of monocyclic hydrocarbon groups include groups having a cycloalkane structure such as a cyclohexylene group and a cyclohexyl group, and groups having a cycloalkene skeleton such as a cyclodecatrienediyl group and a cyclodecatriene group. Specific examples of polycyclic hydrocarbon groups include groups having a dicyclopentadiene skeleton such as a tricyclodecanediyl group, a dicyclopentanyl group, and a dicyclopentenyl group, groups having a norbornane skeleton such as a norbornanediyl group, an isobornanediyl group, a norbornyl group, and groups having an adamantane skeleton such as an adamantanediyl group and an adamantyl group.

[0128] The alicyclic hydrocarbon group in the alicyclic bifunctional (meth)acrylate monomer is preferably a group having a dicyclopentadiene skeleton, from the viewpoint of further improving the performance balance between the moldability and transparency of the optical molded body. Also, the alicyclic bifunctional (meth)acrylate monomer preferably contains tricyclodecane dimethanol di(meth)acrylate, from the viewpoint of further improving the performance balance between the moldability and transparency of the optical molded body.

[0129] <(Meth)acrylate Polymer (B) Having an Alicyclic Skeleton> The (meth)acrylate polymer (B) is a polymer obtained by polymerizing a monomer component containing a compound having an alicyclic skeleton and a (meth)acryloyl group.

[0130] For example, a (meth)acrylate monomer (A) can be used to synthesize the (meth)acrylate polymer (B). For example, a thermal polymerization initiator or a photopolymerization initiator (C) can be used to synthesize the (meth)acrylate polymer (B). Specifically, the method described in the examples can be used to synthesize the (meth)acrylate polymer (B) of the second embodiment.

[0131] The (meth)acrylate polymer (B) of the second embodiment has an alicyclic skeleton from the viewpoint of being able to reduce the occurrence of cracks in the optical molded body and to improve the performance balance between the moldability and transparency of the optical molded body. From the viewpoint of being able to reduce the occurrence of cracks in the optical molded body and to improve the performance balance between the moldability and transparency of the optical molded body, the (meth)acrylate polymer (B) of the second embodiment preferably has one or more skeletons selected from the group consisting of an adamantane skeleton, a norbornane skeleton, a dicyclopentadiene skeleton, an isobornyl skeleton, and a cyclohexane skeleton, and more preferably has one or more skeletons selected from the group consisting of a dicyclopentadiene skeleton and a norbornane skeleton.

[0132] From the viewpoint of being able to reduce the occurrence of cracks in the optical molded body and being able to improve the performance balance between the moldability and transparency of the optical molded body, the (meth)acrylate polymer (B) of the second embodiment preferably contains a repeating unit derived from a (meth)acrylate monomer (A) having an alicyclic skeleton, more preferably contains a repeating unit derived from a (meth)acrylate monomer (A) having one or more skeletons selected from the group consisting of an adamantane skeleton, a norbornane skeleton, a dicyclopentadiene skeleton, an isobornyl skeleton, and a cyclohexane skeleton, and even more preferably contains a repeating unit derived from one or more (meth)acrylate monomers (A) selected from the group consisting of dicyclopentanyl (meth)acrylate and isobornyl (meth)acrylate.

[0133] From the viewpoint of being able to reduce the occurrence of cracks in the optical molded body and being able to improve the performance balance between the moldability and transparency of the optical molded body, the (meth)acrylate polymer (B) of the second embodiment preferably contains one or two or more repeating units selected from the group consisting of repeating units derived from a monofunctional (meth)acrylate monomer (A1) and repeating units derived from a difunctional or higher functional (meth)acrylate monomer (A2), more preferably contains one or two or more repeating units selected from the group consisting of repeating units derived from a monofunctional (meth)acrylate monomer (A1) and repeating units derived from a difunctional (meth)acrylate monomer (A2), and even more preferably contains a repeating unit derived from a monofunctional (meth)acrylate monomer (A1).

[0134] From the viewpoint of further reducing the occurrence of cracks in the optical molded body, the weight average molecular weight Mw of the (meth)acrylate polymer (B) of the second embodiment is preferably 3,000 or more, more preferably 3,500 or more, even more preferably 4,000 or more, even more preferably 4,500 or more, even more preferably 5,000 or more, even more preferably 5,500 or more, even more preferably 6,000 or more, even more preferably 6,500 or more, even more preferably 7,000 or more, and even more preferably 7,500 or more. Specifically, the method for measuring the weight average molecular weight Mw of the (meth)acrylate polymer (B) of the second embodiment can be the same as that described in the examples.

[0135] From the viewpoint of improving the transparency of the optical molded body, the weight average molecular weight Mw of the (meth)acrylate polymer (B) of the second embodiment is preferably 5,000,000 or less, more preferably 4,500,000 or less, even more preferably 4,000,000 or less, even more preferably 3,500,000 or less, even more preferably 3,000,000 or less, even more preferably 2,500,000 or less, even more preferably 2,000,000 or less, even more preferably 1,500,000 or less, even more preferably 1,000,000 or less, even more preferably 500,000 or less, even more preferably 250,000 or less, even more preferably 200,000 or less, even more preferably 150,000 or less, even more preferably 100,000 or less, even more preferably 50,000 or less, and even more preferably 40,000 or less.

[0136] The weight average molecular weight Mw of the (meth)acrylate polymer (B) of the second embodiment is, from the viewpoint of reducing the occurrence of cracks in the optical molded body and improving the balance of the moldability and transparency of the optical molded body, preferably 3,000 or more and 5,000,000 or less, more preferably 3,000 or more and 4,500,000 or less, even more preferably 3,000 or more and 4,000,000 or less, still more preferably 3,000 or more and 3,500,000 or less, still more preferably 3,000 or more and 3,000,000 or less, still more preferably 3,000 or more and 2,500,000 or less, still more preferably 3,000 or more and 2,000,000 or less, still more preferably 3,000 or more and 1,500,000 or less. 0 or less, more preferably 3,000 or more and 1,000,000 or less, even more preferably 3,000 or more and 500,000 or less, even more preferably 3,000 or more and 250,000 or less, even more preferably 3,500 or more and 200,000 or less, even more preferably 4,000 or more and 150,000 or less, even more preferably 4,500 or more and 100,000 or less, even more preferably 5,000 or more and 100,000 or less, even more preferably 5,500 or more and 50,000 or less, even more preferably 6,000 or more and 40,000 or less, even more preferably 6,500 or more and 40,000 or less, even more preferably 7,000 or more and 40,000 or less, even more preferably 7,500 or more and 40,000 or less.

[0137] In the (meth)acrylate polymer (B) of the second embodiment, the repeating units derived from the (meth)acrylate monomer (A) having an alicyclic skeleton preferably account for 10 mol % or more and 100 mol % or less, more preferably 50 mol % or more and 100 mol % or less, even more preferably 85 mol % or more and 100 mol % or less, even more preferably 90 mol % or more and 100 mol % or less, and even more preferably 95 mol % or more and 100 mol % or less, when the total number of moles of repeating units in the (meth)acrylate polymer (B) is taken as 100 mol %, from the viewpoint of being able to reduce the occurrence of cracks in the optical molded body and being able to improve the performance balance between the moldability and transparency of the optical molded body.

[0138] From the viewpoint of reducing the occurrence of cracks in the optical molded body and improving the performance balance between the moldability and transparency of the optical molded body, the content of the (meth)acrylate polymer (B) in the photocurable resin composition of the second embodiment is preferably 0.5 parts by mass or more and 90 parts by mass or less, more preferably 1 part by mass or more and 90 parts by mass or less, even more preferably 5 parts by mass or more and 80 parts by mass or less, even 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 60 parts by mass or less, and even more preferably 15 parts by mass or more and 50 parts by mass or less, when the content of the (meth)acrylate monomer (A) is taken as 100 parts by mass.

[0139] From the viewpoint of being able to reduce the occurrence of cracks in the optical molded body and being able to improve the performance balance between the moldability and transparency of the optical molded body, the content of the (meth)acrylate polymer (B) in the photocurable resin composition of the second embodiment is preferably 1% by mass or more and 90% by mass or less, more preferably 2% by mass or more and 50% by mass or less, even more preferably 5% by mass or more and 40% by mass or less, even more preferably 9% by mass or more and 30% by mass or less, and even more preferably 10% by mass or more and 25% 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.

[0140] <Photopolymerization initiator (C)> 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 when irradiated 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.

[0141] Examples of the photopolymerization initiator (C) include benzophenone, Michler's ketone (4,4'-bis(dimethylamino)benzophenone), 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, and 2,2-diethoxyacetophenone. benzophenone, 2,2-dimethoxy-2-phenylacetophenone, camphorquinone, benzanthrone, ethyl 4-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 azine, 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-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-mol 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,Examples of such oxime include 6-trimethylbenzoyldiphenylphosphine oxide, 2,4,6-trimethylbenzoyldiphenylphosphinic acid ester, 1-[4-(phenylthio)phenyl]-1,2-octanedione-2-(O-benzoyloxime), and 1-[9-ethyl-6-(2-methylbenzoyl)-9H-carbazol-3-yl]-ethanone-1-(O-acetyloxime).

[0142] From the viewpoint of further improving the balance of the moldability and transparency of the optical molded body, the photopolymerization initiator (C) preferably contains a hydroxyphenyl ketone initiator, and more preferably contains 1-hydroxycyclohexyl phenyl ketone.

[0143] From the viewpoint of being able to reduce the occurrence of cracks in the optical molded body and being able to improve the performance balance between the moldability and transparency of the optical molded body, the content of the photopolymerization initiator (C) in the photocurable resin composition of the second embodiment is preferably 0.1 parts by mass or more and 10 parts by mass or less, more preferably 1 part by mass or more and 9 parts by mass or less, even more preferably 2 parts by mass or more and 8 parts by mass or less, even more preferably 5 parts by mass or more and 7 parts by mass or less, and even more preferably 5.5 parts by mass or more and 6.5 parts by mass or less, when the content of the (meth)acrylate monomer (A) is taken as 100 parts by mass.

[0144] From the viewpoint of being able to reduce the occurrence of cracks in the optical molded body and being able to improve the performance balance between the moldability and transparency of the optical molded body, the content of the photopolymerization initiator (C) in the photocurable resin composition of the second embodiment is preferably 0.1% by mass or more and 10% by mass or less, more preferably 1% by mass or more and 8% by mass or less, even more preferably 2% by mass or more and 6% by mass or less, even more preferably 3% by mass or more and 5% 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.

[0145] From the viewpoint of reducing the occurrence of cracks in the optical molded body and improving the performance balance between the moldability and transparency of the optical molded body, the total content of the (meth)acrylate monomer (A), the (meth)acrylate polymer (B), and the photopolymerization initiator (C) in the photocurable resin composition of the second embodiment is preferably 50% by mass or more and 100% by mass or less, more preferably 60% by mass or more and 95% by mass or less, even more preferably 70% by mass or more and 90% by mass or less, even more preferably 75% by mass or more and 85% by mass or less, and even more preferably 78% by mass or more and 80% 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.

[0146] <Monomer component (G) other than (meth)acrylate monomer (A)> From the viewpoint of improving the brittleness of the optical molded body, the photocurable resin composition of the second embodiment preferably further includes a monomer component (G) other than the (meth)acrylate monomer (A) (hereinafter also simply referred to as "monomer (G)"), and more preferably further includes a monofunctional or di- or higher functional (meth)acrylate monomer (excluding the (meth)acrylate monomer (A)). The photocurable resin composition of the second embodiment further preferably includes a di- or higher functional (meth)acrylate monomer (excluding the (meth)acrylate monomer (A2)), still more preferably includes a linear difunctional (meth)acrylate monomer, still more preferably includes 1,12-dodecanediol (meth)acrylate, and still more preferably includes 1,12-dodecanediol dimethacrylate.

[0147] The linear bifunctional (meth)acrylate monomer is a compound having a linear structure and two (meth)acryloyl groups. The linear structure preferably contains a divalent linear hydrocarbon group from the viewpoint of further improving crack resistance during molding of the optical molded body. The number of carbon atoms in the divalent linear hydrocarbon group is preferably 1 or more, more preferably 2 or more, and even 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, the number of carbon atoms in the divalent linear hydrocarbon group is preferably 20 or less, more preferably 14 or less, from the viewpoint of improving heat resistance.

[0148] Examples of linear bifunctional (meth)acrylate monomers include di(meth)acrylates of alkanediols, such as 1,6-hexanediol di(meth)acrylate, 1,9-nonanediol di(meth)acrylate, 1,10-decanediol di(meth)acrylate, 1,12-dodecanediol di(meth)acrylate, ethylene glycol di(meth)acrylate, triethylene glycol di(meth)acrylate, polyethylene glycol di(meth)acrylate, 1,3-butanediol di(meth)acrylate, and 1,4-butanediol di(meth)acrylate.

[0149] From the viewpoint of improving the brittleness of the optical molded body, the content of the monomer (G) in the photocurable resin composition of the second embodiment is preferably 0 parts by mass or more and 60 parts by mass or less, more preferably 5 parts by mass or more and 55 parts by mass or less, even more preferably 10 parts by mass or more and 50 parts by mass or less, even more preferably 20 parts by mass or more and 45 parts by mass or less, and even more preferably 25 parts by mass or more and 40 parts by mass or less, when the content of the (meth)acrylate monomer (A) is taken as 100 parts by mass.

[0150] From the viewpoint of improving the brittleness of the optical molded body, the content of monomer (G) in the photocurable resin composition of the second embodiment is preferably 0% by mass or more and 40% by mass or less, more preferably 5% by mass or more and 35% by mass or less, even more preferably 10% by mass or more and 30% by mass or less, even more preferably 12% by mass or more and 25% by mass or less, and even more preferably 15% by mass or more and 20% 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.

[0151] <Antioxidant (D)> The photocurable resin composition of the second embodiment may further contain an antioxidant (D). The type of antioxidant (D) is not particularly limited, and known antioxidants can be used. Examples of the antioxidant (D) include phenol-based antioxidants, phosphorus-based antioxidants, sulfur-based antioxidants, hindered amine-based antioxidants, and thioether-based antioxidants.

[0152] Examples of phenolic antioxidants include 2,6-di-t-butylhydroxytoluene and pentaerythritol-tetrakis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate].

[0153] Examples of phosphorus-based antioxidants include phosphines such as trialkylphosphine and triarylphosphine, trialkyl phosphites, and triaryl phosphites.

[0154] 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), and 3,9-bis(2-dodecylthioethyl)-2,4,8,10-tetraoxaspiro[5,5]undecane.

[0155] 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.

[0156] 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].

[0157] The content of the antioxidant (D) in the photocurable resin composition of the second embodiment, when the content of the (meth)acrylate monomer (A) is taken as 100 parts by mass, is preferably 0.01 parts by mass or more and 10 parts by mass or less, more preferably 0.1 parts by mass or more and 8.0 parts by mass or less, even more preferably 1.0 parts by mass or more and 7.0 parts by mass or less, even more preferably 2.0 parts by mass or more and 6.0 parts by mass or less, and even more preferably 3.0 parts by mass or more and 5.0 parts by mass or less, from the viewpoint of being able to reduce the occurrence of cracks in the optical molded body and being able to improve the performance balance between the moldability and transparency of the optical molded body.

[0158] The content of the antioxidant (D) in the photocurable resin composition of the second embodiment is preferably 0.01% by mass or more and 5% by mass or less, more preferably 0.1% by mass or more and 4% by mass or less, even more preferably 0.5% by mass or more and 3.5% by mass or less, even more preferably 1.0% by mass or more and 3.0% by mass or less, and even more preferably 2.0% by mass or more and 2.5% by mass or less, from the viewpoint of being able to reduce the occurrence of cracks in the optical molded body and being able to improve the performance balance between the moldability and transparency of the optical molded body, when the total amount of solids in the photocurable resin composition (the total amount of components that remain as solids when the composition is cured) is taken as 100% by mass.

[0159] <Light Stabilizer (E)> The photocurable resin composition of the second embodiment may further contain a light stabilizer (E). The type of light stabilizer (E) is not particularly limited, and known light stabilizers can be used. The light stabilizer (E) can improve the coloration resistance of the photocurable resin composition. From the viewpoint of further improving coloration resistance, the light stabilizer (E) preferably contains a hindered amine-based light stabilizer.

[0160] Examples of hindered amine light stabilizers include bis(1-octyloxy-2,2,6,6-tetramethyl-4-piperidyl)sebacic acid, 1,2,2,6,6-pentamethyl-4-piperidyl methacrylate, decanedioic acid bis(2,2,6,6-tetramethyl-1(octyloxy)-4-piperidinyl)ester, a reaction product of 70% by mass 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 methyl-1,2,2,6,6-pentamethoxysilane. tridecyl-4-piperidyl sebacate mixture, 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.

[0161] The content of the light stabilizer (E) in the photocurable resin composition of the second embodiment, when the content of the (meth)acrylate monomer (A) is taken as 100 parts by mass, is preferably 0.01 parts by mass or more and 10 parts by mass or less, more preferably 0.05 parts by mass or more and 5 parts by mass or less, even more preferably 0.1 parts by mass or more and 3 parts by mass or less, even more preferably 0.2 parts by mass or more and 2 parts by mass or less, and even more preferably 0.5 parts by mass or more and 1.5 parts by mass or less, from the viewpoint of being able to reduce the occurrence of cracks in the optical molded body and being able to improve the performance balance between the moldability and transparency of the optical molded body.

[0162] The content of the light stabilizer (E) in the photocurable resin composition of the second embodiment is preferably 0.01% by mass or more and 5% by mass or less, more preferably 0.02% by mass or more and 4% by mass or less, even more preferably 0.05% by mass or more and 3% by mass or less, even more preferably 0.1% by mass or more and 2% by mass or less, and even more preferably 0.2% by mass or more and 1% by mass or less, from the viewpoint of being able to reduce the occurrence of cracks in the optical molded body and being able to improve the performance balance between the moldability and transparency of the optical molded body, when the total amount of solids in the photocurable resin composition (the total amount of components that remain as solids when the composition is cured) is taken as 100% by mass.

[0163] <Chain Transfer Agent (F)> The photocurable resin composition of the second embodiment may further contain a chain transfer agent (F). The type of chain transfer agent (F) is not particularly limited, and a known chain transfer agent can be used. When the photocurable resin composition contains the chain transfer agent (F), it is possible to adjust the molecular weight of the (meth)acrylate monomer (A) after radical polymerization.

[0164] Examples of the chain transfer agent (F) include mercaptans, secondary thiols, and primary thiols.

[0165] Examples of mercaptans include t-dodecyl mercaptan, n-dodecyl mercaptan, t-octyl mercaptan, and n-octyl mercaptan.

[0166] Examples of secondary thiols include pentaerythritol tetrakis(3-mercaptobutyrate), 1,4-bis(3-mercaptobutyryloxy)butane, 1,3,5-tris(2-(3-sulfanylbutanoyloxy)ethyl)-1,3,5-triazinane-2,4,6-trione, and trimethylolpropane tris(3-mercaptobutyrate).

[0167] Examples of primary thiols include 2,2-bis[[(3-mercaptopropionyl)oxy]methyl]trimethylenebis[3-mercaptopropionate], 3-mercaptopropionic acid ester of dipentaerythritol, tris-[(3-mercaptopropionyloxy)-ethyl]-isocyanurate, tetraethylene glycol bis(3-mercaptopropionate), 2-ethylhexyl-3-mercaptopropionate, and methoxybutyl-β-mercaptopropionate. Furthermore, examples of primary thiols include 2-ethyl-2-{[(3-sulfanylpropanoyl)oxy]methyl}propane-1,3-diyl bis(3-sulfanylpropanoate), 2-ethyl-2-[({3-[(3-sulfanylpropanoyl)sulfanyl]propanoyl}oxy)methyl]propane-1,3-diyl bis(3-sulfanylpropanoate), 2-ethyl-2-(hydroxymethyl)propane-1,3-diyl bis(3-sulfanylpropanoate), and mixtures thereof.

[0168] From the viewpoint of further improving the performance balance between the moldability and transparency of the optical molded body, the chain transfer agent (F) preferably contains one or more selected from the group consisting of mercaptans and secondary thiols, more preferably contains a secondary thiol, and even more preferably contains pentaerythritol tetrakis(3-mercaptobutyrate).

[0169] The content of the chain transfer agent (F) in the photocurable resin composition of the second embodiment is preferably 0 parts by mass or more and 5 parts by mass or less, more preferably 0 parts by mass or more and 3 parts by mass or less, even more preferably 0 parts by mass or more and 2.5 parts by mass or less, and even more preferably 0 parts by mass or more and 2 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 further improving the performance balance between the moldability and transparency of the optical molded body.

[0170] The content of the chain transfer agent (F) in the photocurable resin composition of the second embodiment is preferably 0% by mass or more and 5% by mass or less, more preferably 0% by mass or more and 3% by mass or less, even more preferably 0% by mass or more and 2% by mass or less, and even more preferably 0% by mass or more and 1% by mass or less, from the viewpoint of further improving the performance balance between the moldability and transparency of the optical molded body, 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.

[0171] <Other Components> The photocurable resin composition of the second embodiment may contain components other than the (meth)acrylate monomer (A), the (meth)acrylate polymer (B), the photopolymerization initiator (C), the monomer component (G) other than the (meth)acrylate monomer (A) (monomer (G)), the antioxidant (D), the light stabilizer (E), and the chain transfer agent (F). Examples of the other components include 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.

[0172] <Method for producing photocurable resin composition> The photocurable resin composition of the second embodiment can be obtained by mixing the (meth)acrylate monomer (A), the (meth)acrylate polymer (B), and the photopolymerization initiator (C), and, if necessary, the monomer (G), the antioxidant (D), the light stabilizer (E), the chain transfer agent (F), and other components, by a conventionally known method. Note that the method for producing the photocurable resin composition, more specifically, the method described in the examples, can be adopted.

[0173] <Physical Properties of Photocurable Resin Composition> Next, the physical properties of the photocurable resin composition will be described.

[0174] <Humidity swelling ratio α1> For the photocurable resin composition of the second embodiment, the humidity swelling ratio α1 measured in accordance with the above-mentioned <Humidity-conditioned thermomechanical analysis (humidity-conditioned TMA)> for a cured film produced using the photocurable resin composition in accordance with the above-mentioned <Cured film production conditions> will be described.

[0175] From the viewpoint of reducing the occurrence of cracks in the optical molded body, the humidity swelling ratio α1 of the photocurable resin composition of the second embodiment is 0.35% or less, preferably 0.30% or less, more preferably 0.28% or less, even more preferably 0.27% or less, even more preferably 0.26% or less, even more preferably 0.25% or less, even more preferably 0.24% or less, even more preferably 0.23% or less, even more preferably 0.22% or less, and even more preferably 0.21% or less.

[0176] From the viewpoint of further reducing the occurrence of cracks in the optical molded body, the lower limit of the humidity swelling rate α1 of the photocurable resin composition of the second embodiment is preferably −0.35% or more, more preferably −0.30% or more, even more preferably −0.20% or more, even more preferably −0.10% or more, even more preferably 0.00% or more, even more preferably 0.01% or more, even more preferably 0.03% or more, even more preferably 0.05% or more, even more preferably 0.08% or more, and even more preferably 0.10% or more.

[0177] From the viewpoint of reducing the occurrence of cracks in the optical molded body, the humidity swelling rate α1 of the photocurable resin composition of the second embodiment is 0.35% or less, preferably −0.35% or more and 0.35% or less, more preferably −0.30% or more and 0.30% or less, even more preferably −0.20% or more and 0.28% or less, even more preferably −0.10% or more and 0.27% or less, even more preferably 0.00% or more and 0.26% or less, even more preferably 0.01% or more and 0.25% or less, even more preferably 0.03% or more and 0.24% or less, even more preferably 0.05% or more and 0.23% or less, even more preferably 0.08% or more and 0.22% or less, and even more preferably 0.10% or more and 0.21% or less.

[0178] <Humidity Swelling Ratio α2> For the photocurable resin composition of the second embodiment, the humidity swelling ratio α2 measured in the humidity-controlled thermomechanical analysis (humidity-controlled TMA) of a cured film produced using the photocurable resin composition according to the above <Cured Film Production Conditions> will be described. The humidity swelling ratio in the humidity-lowering step of the humidity-controlled thermomechanical analysis (humidity-controlled TMA) is defined as the humidity swelling ratio α2.

[0179] From the viewpoint of further reducing the occurrence of cracks in the optical molded body, the humidity swelling rate α2 of the photocurable resin composition of the second embodiment is preferably 0.30% or less, more preferably −0.30% or more and 0.30% or less, even more preferably −0.20% or more and 0.25% or less, even more preferably −0.10% or more and 0.20% or less, even more preferably 0.00% or more and 0.15% or less, even more preferably 0.01% or more and 0.13% or less, and even more preferably 0.03% or more and 0.12% or less.

[0180] For the photocurable resin composition of the second embodiment, the water absorption measured in accordance with the <Water Absorption Measurement> below for an optical molded body produced according to the <Optical Molded Body Production Conditions> below will be described. More specifically, the conditions described in the Examples can be used as the production conditions for the optical molded body. More specifically, the method described in the Examples can be used as the method for measuring the water absorption of the photocurable resin composition.

[0181] The water absorption of the photocurable resin composition of the second embodiment is preferably 0.34% or less, more preferably 0.00% or more and 0.34% or less, even more preferably 0.01% or more and 0.33% or less, even more preferably 0.05% or more and 0.33% or less, even more preferably 0.10% or more and 0.32% or less, and even more preferably 0.15% or more and 0.32% or less, from the viewpoint of being able to reduce the occurrence of cracks in the optical molded body and being able to improve the performance balance between the moldability and transparency of the optical molded body.

[0182] <Conditions for Producing an Optical Molded Body> A pair of glass molds are placed at a predetermined distance. Next, tape is attached to the outer peripheral surfaces of the pair of glass molds in the circumferential direction to seal the space between the pair of glass molds. Next, the photocurable resin composition of the second embodiment is injected and filled into the sealed space via an injection nozzle. Thereafter, the photocurable resin composition is irradiated with LED light having a wavelength of 405 nm at 810 mW for 3 minutes from above the pair of glass molds. Then, the glass molds are turned over and irradiated with LED light having a wavelength of 405 nm at 810 mW for 3 minutes. Then, the glass molds are allowed to cool at 23°C for 30 minutes. Next, the tape is removed and the glass molds are released to obtain an optical molded body.

[0183] <Water Absorption Measurement> The optical molded body is dried at a temperature of 23°C and a relative humidity of 5% or less for 16 hours. Then, the pre-test mass of the optical molded body is measured. Then, the optical molded body is left in a thermo-hygrostat chamber at a temperature of 65°C and a relative humidity of 90% for 504 hours. Then, the post-test mass of the optical molded body taken out of the thermo-hygrostat chamber is measured. Then, the water absorption is calculated using the following formula (1). Formula (1): Water absorption = {(post-test mass) - (pre-test mass)} / (pre-test mass) x 100

[0184] <Viscosity> The viscosity of the photocurable resin composition of the second embodiment is described below, measured using an E-type viscometer at a temperature of 25°C and a rotation speed of 2.5 rpm. More specifically, the method described in the examples can be used to measure the viscosity of the photocurable resin composition. In the second embodiment, the viscosity of the photocurable resin composition is preferably 10 mPa·s or more and 500 mPa·s or less, more preferably 15 mPa·s or more and 400 mPa·s or less, even more preferably 20 mPa·s or more and 300 mPa·s or less, even more preferably 30 mPa·s or more and 200 mPa·s or less, even more preferably 35 mPa·s or more and 150 mPa·s or less, and even more preferably 40 mPa·s or more and 120 mPa·s or less, from the viewpoint of reducing the occurrence of cracks in the optical molded body and improving the performance balance between the moldability and transparency of the optical molded body.

[0185] <Haze Value> For the photocurable resin composition of the second embodiment, the haze value of a cured film prepared according to the following <Cured Film Preparation Conditions 2>, measured in accordance with JIS K 7136:2000, at a thickness of 3.0 mm, will be described. From the viewpoint of further improving the performance balance between moldability and transparency of the optical molded body, the haze value is preferably less than 1.0%, more preferably 0.90% or less, even more preferably 0.80% or less, even more preferably 0.70% or less, even more preferably 0.65% or less, even more preferably 0.60% or less, even more preferably 0.55% or less, even more preferably 0.50% or less, and even more preferably 0.45% or less. The lower limit of the haze value is not particularly limited, but may be, for example, 0.01% or more, 0.05% or more, or 0.1% or more.

[0186] <Cured Film Preparation Condition 2> 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 was placed on a 0.7 mm thick, 50 mm x 50 mm alkali-free glass. Next, the circular hole was filled with a photocurable resin composition, and a 0.7 mm thick, 50 mm x 50 mm alkali-free glass was then placed on top of it. This was then placed on a SUS lab jack to adjust the height. Next, the photocurable resin composition was irradiated with LED light having a wavelength of 405 nm at 810 mW for 3 minutes from above the alkali-free glass, and then turned over and irradiated with LED light having a wavelength of 405 nm at 810 mW for 3 minutes. After irradiating with LED light, the glass was allowed to cool at 23°C for 30 minutes, and the cured product of the photocurable resin composition was released from the alkali-free glass and silicone sheet to obtain a cured film. More specifically, the <Cured Film Preparation Conditions 2> for the photocurable resin composition of the second embodiment can be the conditions described in the Examples. Also, more specifically, the method for measuring the haze value of the photocurable resin composition can be the method described in the Examples.

[0187] <Uses of Photocurable Resin Composition> Next, uses of the photocurable resin composition will be described.

[0188] The photocurable resin composition of the second embodiment can reduce the occurrence of cracks in an optical molded body molded from the photocurable resin composition, and therefore can be used in methods for molding an optical molded body, such as injection molding, compression molding, injection compression molding, extrusion molding, solution casting, and casting. In particular, the photocurable resin composition of the second embodiment can be used in casting.

[0189] The photocurable resin composition of the second embodiment can reduce the occurrence of cracks in optical molded bodies molded from the photocurable resin composition, and therefore the use of the photocurable resin composition is not particularly limited, and the composition can be used for a variety of purposes.

[0190] The photocurable resin composition of the second embodiment can be preferably used for, for example, a lens, which may include, 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.

[0191] The photocurable resin composition of the second 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).

[0192] The photocurable resin composition of the second 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.

[0193] The photocurable resin composition of the second 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).

[0194] (Cured Product) The cured product of the first embodiment is a cured product of the photocurable resin composition of the first embodiment. The cured product of the first embodiment can be produced, for example, by irradiating the photocurable resin composition of the first embodiment with LED light to cure it. Note that, as more specific production conditions for the cured product of the first embodiment, for example, the conditions described in the examples can be adopted.

[0195] (Optical Molded Body) The optical molded body of the second embodiment includes a cured product of the photocurable resin composition of the second embodiment. The optical molded body of the second embodiment can be manufactured using the photocurable resin composition of the second embodiment. The optical molded body can be manufactured from the photocurable resin composition of the second embodiment by any method, such as injection molding, compression molding, injection compression molding, extrusion molding, solution casting, or casting.

[0196] The optical molded body of the second 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.

[0197] The lens of the second 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).

[0198] The optical molded body of the second 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.

[0199] The cover display of the second embodiment includes one or more types selected from the group consisting of a cover display for a virtual reality device (cover display for a VR device), a cover display for a mixed reality device (cover display for an MR device), a cover display for an augmented reality device (cover display for an AR device), a cover display for a cross reality device (cover display for an xR device), and a cover display for a head-mounted display (cover display for an HMD).

[0200] 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.

[0201] For example, in the optical molded body of the second embodiment, the maximum thickness portion is preferably 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.

[0202] The photocurable resin composition of the second embodiment can reduce the occurrence of cracks in the optical molded body, and therefore can be applied to optical molded bodies having a thickness of 1.0 mm or more.

[0203] (Optical Device) The optical device of the second embodiment includes the optical molded body of the second embodiment. The type of the optical device of the second embodiment is not particularly limited. Examples of the optical device of the second 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).

[0204] Although the second embodiment of the present invention has been described above, these are merely examples of the second embodiment of the present invention, and various other configurations may be adopted. Furthermore, the second embodiment of the present invention is not limited to the above-described embodiment, and modifications and improvements that do not impair the effects of the second embodiment of the present invention are included in the second embodiment of the present invention.

[0205] While 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 within the scope of achieving the object of the present invention are included in the present invention.

[0206] Additionally, the present invention also includes configurations that combine the configurations of the above-described embodiments.

[0207] The first embodiment will be described in detail below with reference to examples, etc. However, the first embodiment is not limited to the descriptions of these examples.

[0208] <<Examples 1A to 14A and Comparative Examples 1A to 5A>> The first embodiment of the present invention will be described in detail below with reference to Examples 1A to 14A and Comparative Examples 1A to 5A. Note that the first embodiment is not limited to the descriptions of these examples.

[0209] First, the materials used in Examples 1A to 14A and Comparative Examples 1A to 5A will be described. First, the materials used as the (meth)acrylate monomer (A) and the monomer component (G) other than the (meth)acrylate monomer (A) will be described. <(Meth)acrylate Monomer (A)> Monofunctional alicyclic (meth)acrylate monomer: GM81HDA (dicyclopentanyl methacrylate, manufactured by Kunisei Chemical Co., Ltd.) Monofunctional alicyclic (meth)acrylate monomer: FA-513AS (dicyclopentanyl acrylate, manufactured by Resonac Corporation) Monofunctional alicyclic (meth)acrylate monomer: Light Ester IB-X (isobornyl methacrylate, manufactured by Kyoeisha Chemical Co., Ltd.) (hereinafter also referred to as IBX) Bifunctional or higher functional alicyclic (meth)acrylate monomer: DCP (tricyclodecane dimethanol dimethacrylate, manufactured by Shin-Nakamura Chemical Co., Ltd.)

[0210] <Monomer Component (G) Other than (Meth)acrylate Monomer (A)> Difunctional or higher linear (meth)acrylate monomer: DDD (1,12-dodecanediol dimethacrylate, manufactured by Shin-Nakamura Chemical Co., Ltd.)

[0211] Next, materials used as the (meth)acrylate polymer (B) and polymers other than the (meth)acrylate polymer (B) will be described. The materials, synthesis methods, and measurement method of the weight-average molecular weight Mw used in the synthesis of the following polymers 1A to 6A will be described later. <(Meth)acrylate polymer (B)> Polymer 1A: Polymer having an alicyclic skeleton (weight-average molecular weight Mw: 5,000) Polymer 2A: Polymer having an alicyclic skeleton (weight-average molecular weight Mw: 80,000) Polymer 3A: Polymer having an alicyclic skeleton (weight-average molecular weight Mw: 80,000) Polymer 4A: Polymer having an alicyclic skeleton (weight-average molecular weight Mw: 80,000) Polymer 5A: Polymer having an alicyclic skeleton (weight-average molecular weight Mw: 1,700,000)

[0212] <Polymers other than (meth)acrylate polymer (B)> Polymer 6A: Polymer not having an alicyclic skeleton (weight average molecular weight Mw: 4,500)

[0213] Next, other materials used in the photocurable resin composition will be described. Photopolymerization initiator (C): photoradical polymerization initiator (1-hydroxycyclohexyl phenyl ketone, manufactured by IGM Resins, product name: Omnirad 184) Antioxidant (D): pentaerythritol-tetrakis[3-(3',5'-di-tert-butyl-4'-hydroxyphenyl)propionate (product name: Irganox 1010, manufactured by BASF) Light stabilizer (E): bis(1-octyloxy-2,2,6,6-tetramethyl-4-piperidyl)sebacic acid (product name: Tinuvin 123, manufactured by BASF) Chain transfer agent (F): t-dodecyl mercaptan (hereinafter also referred to as t-DM)

[0214] Next, the materials used in the synthesis of the above polymers 1A to 6A will be described. The monomer composition of each polymer is as shown in Table 2. Materials used in synthesizing polymers 1A to 6A Monomer: monofunctional alicyclic methacrylate monomer (GM81HDA) Monomer: monofunctional alicyclic methacrylate monomer (IBX) Monomer: monofunctional linear acrylate monomer (lauryl acrylate, manufactured by Osaka Organic Chemical Industry Ltd.) (hereinafter also referred to as LA) Monomer: monofunctional linear acrylate monomer (methyl methacrylate) (hereinafter also referred to as MMA) Polymerization initiator: 2,2'-azobis(2-methylpropionate)dimethyl (product name: V-601, manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.) 2,2'-azobis(isobutyronitrile) (product name: AIBN, manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.) Chain transfer agent: t-dodecyl mercaptan (t-DM) (manufactured by Tokyo Chemical Industry Co., Ltd.) Polymerization inhibitor: 2,4-dimethyl-6-tert-butylphenol (product name: Topanol A, manufactured by Tokyo Chemical Industry Co., Ltd.) Solvent: butyl acetate (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.)

[0215] Polymers 1A to 4A and Polymer 6A were each synthesized by the following method. 326 g of a solvent (butyl acetate) was placed in a 1 L glass four-neck round-bottom flask equipped with a stirrer. The monomers and polymerization initiator were each weighed out according to the information in Table 2. While maintaining the internal temperature of the four-neck round-bottom flask at 95°C, the weighed monomers and polymerization initiator were each added dropwise to the solvent over 360 minutes to prepare a mixed solution. Next, the mixed solution was stirred at 95°C for 270 minutes to allow the polymerization reaction to proceed. Thereafter, a solution prepared by dissolving 2 g of polymerization initiator (V-601) in 35 g of butyl acetate was added dropwise to the mixed solution to polymerize the remaining monomers. After the dropwise addition, the mixed solution was stirred at 110°C for 120 minutes to allow the polymerization reaction to proceed. The mixture was then cooled to room temperature (23°C) over 60 minutes. After cooling, 300 g of the mixed solution was dispensed into another 5 L four-neck round-bottom flask. Next, 3,500 g of methanol was added dropwise to the dispensed mixture to obtain a precipitate. The separated precipitate was washed with 900 mL of methanol. Thereafter, the precipitate was dried in a dryer under vacuum at 85°C for 120 minutes to obtain a polymer.

[0216] Polymer 5A was synthesized by the following method. Monomers were weighed and added to a 1 L four-necked glass round-bottom flask equipped with a stirrer according to the description in Table 2. The internal temperature of the four-necked round-bottom flask was then raised to 50°C, and a polymerization initiator and a chain transfer agent were weighed and added according to the description in Table 2. The mixture was then heated to 75°C, and the temperature was maintained at 75°C while stirring for 120 minutes to allow the polymerization reaction to proceed. The reaction was then continued at 75°C until the weight-average molecular weight Mw of a sample collected from the mixture reached 1,500,000. The weight-average molecular weight Mw of the sample was measured using GPC according to the method described below. When the weight-average molecular weight Mw of the sample reached 1,500,000, a polymerization inhibitor was weighed and added according to the description in Table 2 to terminate the polymerization reaction. Next, the content of Polymer 5A in the mixed solution was calculated from the measurement results of GPC, and the mixed solution was diluted with the monomers shown in Table 2 to obtain a syrup containing 10 mass % of Polymer 5A.

[0217] The weight-average molecular weight Mw of the prepared polymers 1A to 6A was measured according to the following <Method for measuring weight-average molecular weight Mw>. The results are shown in Table 2. <Method for measuring weight-average molecular weight Mw> Using gel permeation chromatography (GPC), the weight-average molecular weight Mw of each polymer dissolved in a mobile phase was measured under the following conditions. Column: Two connected PLgel 5 μm MIXED-D, 300 × 7.5 mm (Agilent Technologies) Column temperature: 40°C Mobile phase: HPLC-grade tetrahydrofuran [containing stabilizer] (Fujifilm Wako Pure Chemical Industries, Ltd.) Flow rate: 1.0 mL / min Injection volume: 100 μL Detection method: Differential refractive index detection Column calibration: Monodisperse polystyrene (product name: EasiCal Type PS-1 Polystyrene, Agilent Technologies) Molecular weight calibration: Relative calibration method (polystyrene equivalent) Pump device: KP-22-13S dual pump (Flom Co., Ltd.) Automatic injection device: 717plus (Nihon Waters K.K.) Detector: Differential refractive index detector (product name: RI-101, Shodex)

[0218] (Examples 1A to 14A and Comparative Examples 1A to 5A) Liquid photocurable resin compositions were obtained by blending the components to obtain the formulations shown in Table 1. For Polymer 5A, a syrup containing 10% by mass of Polymer 5A was used so that the blending amount of Polymer 5A was the value in Table 1.

[0219] The photocurable resin composition was prepared as follows: Each component was placed in a light-shielding mixer. While maintaining the temperature inside the mixer at 60°C, the components were mixed and uniformly dissolved to obtain a photocurable resin composition.

[0220] Next, the physical properties of the photocurable resin compositions obtained in each example were measured by the following methods. The measurement results are shown in Table 1.

[0221] <Viscosity Measurement> The viscosity of the photocurable resin composition was measured using an E-type viscometer (product name: TVE-25L, manufactured by Toki Sangyo Co., Ltd.) at a temperature of 25°C and 2.5 rpm. The cone rotor was appropriately selected from 1°34' x R24, 3° x R14, and 3° x R9.7 depending on the viscosity of the photocurable resin composition of each example. The results are shown in Table 1.

[0222] <Method for Measuring Haze Value> For each photocurable resin composition, a cured film was prepared according to the following <Conditions for Preparing Cured Film>, and the haze value of the film was measured in accordance with JIS K 7136:2000 at a thickness of 3.0 mm.

[0223] <Conditions for Producing Cured Films> 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 was placed on a 0.7 mm thick, 50 mm x 50 mm alkali-free glass (product name: JIS R 3202, glass plate, filament surface, manufactured by Test Piece Co., Ltd.). The circular hole in the silicone sheet was filled with a photocurable resin composition, and then a 0.7 mm thick, 50 mm x 50 mm alkali-free glass (product name: JIS R 3202, glass plate, filament surface, manufactured by Test Piece Co., Ltd.) was further placed on top of it. 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 alkali-free glass, filling the circular hole in the silicone sheet with a photocurable resin composition, and then further placing alkali-free glass on top of that may be referred to as a laminate. The above-mentioned laminate was placed on a SUS lab jack, and the height of the SUS lab jack was adjusted. The photocurable resin composition was irradiated from above the alkali-free glass with LED light having a wavelength of 405 nm at 810 mW for 3 minutes 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 laminate was then turned over and irradiated with LED light having a wavelength of 405 nm at 810 mW for an additional 3 minutes. After irradiation with 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 alkali-free glass and silicone sheet to obtain a cured film of the photocurable resin composition. The irradiation intensity of the LED light was measured using an ultraviolet integrating actinometer (product name: UIT-250, manufactured by Ushio Inc.).

[0224] <Evaluation of Moldability> Optical molded bodies were produced using the photocurable resin compositions of each example according to the following <Production Conditions for Optical Molded Body>. Then, the appearance of the optical molded body was visually observed to evaluate the moldability. This evaluation was performed under the condition of n = 15 samples. The optical molded body was rated as A when the number of samples in which striae occurred was 0, B when the number was 1 to 3, and C when the number was 4 or more.

[0225] <Conditions for Producing Optical Molded Body> An optical molded body was produced from a photocurable resin composition using a tape molding method according to the following <Tape Molding Conditions>. A pair of glass molds was placed at a predetermined distance. Tape was attached circumferentially to the outer peripheral surfaces of the glass molds to seal the space between the pair of glass molds. Next, an injection nozzle was inserted into the sealed space, and the photocurable resin composition was injected and filled into the sealed space through the injection nozzle. At this time, care was taken to avoid introducing air bubbles into the sealed space. Thereafter, with the concave surfaces of the pair of glass molds facing 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 from above the pair of glass molds with LED light having a wavelength of 405 nm at 810 mW for 3 minutes using the LED light irradiation device. Next, the pair of glass molds were turned over so that the convex surfaces of the pair of glass molds faced the LED light irradiation device. Subsequently, with the convex surfaces of the pair of glass molds facing the LED light irradiation device, the photocurable resin composition was irradiated with LED light having a wavelength of 405 nm at 810 mW for 3 minutes from above the pair of glass molds using the LED light irradiation device. After irradiating with LED light, the cured product of the photocurable resin composition was allowed to cool at 23°C for 30 minutes. After cooling, the tape was removed and the product was released from the glass mold to obtain an optical molded body. The irradiation intensity of the LED light was measured using an ultraviolet integrating actinometer (product name: UIT-250, manufactured by Ushio Inc.). <Tape molding conditions> A pair of glass molds Spherical glass mold A and spherical glass mold B were arranged so that the center line of spherical glass mold A overlapped with the center line of spherical glass mold B and the concave surface of spherical glass mold A faced the convex surface of spherical glass mold B. Spherical glass mold A: Convex surface radius of curvature: 243 mm, concave surface radius of curvature: 253 mm, thickness: 4.8 mm, diameter: 81 mmφ, double-sided polished spherical glass mold. Spherical glass mold B: Convex surface radius of curvature: 250 mm, concave surface radius of curvature: 216 mm, thickness: 3.6 mm, diameter: 81 mmφ, double-sided polished spherical glass mold. Spacing between glass molds: 3 mm Tape: SLION TAPE 6263, manufactured by Sliontec

[0226] <Evaluation of Turbidity (Evaluation of Transparency)> For each photocurable resin composition, a cured film prepared according to the above <Conditions for preparing a cured film> was immersed in benzyl alcohol at 25°C, and the haze value (haze value when immersed in benzyl alcohol) was measured at a cured film thickness of 3.0 mm in accordance with JIS K 7136: 2000. A haze value when immersed in benzyl alcohol of less than 1.0% was evaluated as A, and a haze value of 1.0% or greater was evaluated as B.

[0227]

[0228]

[0229] <<Examples 1B to 5B and Comparative Example 1B>> The second embodiment of the present invention will be described in detail below with reference to Examples 1B to 5B and Comparative Example 1B. Note that the second embodiment is not limited to the descriptions of these examples.

[0230] First, the materials used in Examples 1B to 5B and Comparative Example 1B will be described. First, the materials used as the (meth)acrylate monomer (A) and the monomer component (G) other than the (meth)acrylate monomer (A) will be described. <(Meth)acrylate Monomer (A)> Monofunctional alicyclic (meth)acrylate monomer: GM81HDA (dicyclopentanyl methacrylate, manufactured by Kokusei Chemical Co., Ltd.) Difunctional or higher functional alicyclic methacrylate monomer (tricyclodecane dimethanol dimethacrylate, manufactured by Shin-Nakamura Chemical Co., Ltd.) (hereinafter also referred to as DCP)

[0231] <Monomer component (G) other than (meth)acrylate monomer (A)> Difunctional or higher linear (meth)acrylate monomer: DDD (1,12-dodecanediol dimethacrylate, manufactured by Shin-Nakamura Chemical Co., Ltd.) Monofunctional linear (meth)acrylate monomer: MMA (methyl methacrylate, manufactured by Asahi Kasei Corporation) Monofunctional aromatic ring maleimide monomer: N-phenylmaleimide (manufactured by Nippon Shokubai Co., Ltd.) (hereinafter also referred to as phMI) Monofunctional alicyclic maleimide monomer: N-cyclohexylmaleimide (manufactured by Nippon Shokubai Co., Ltd.) (hereinafter also referred to as chMI)

[0232] Next, the material used as the (meth)acrylate polymer (B) will be described. The materials, synthesis methods, and measurement method of the weight-average molecular weight Mw used in the synthesis of the following polymer 1B and polymer 2B will be described later. <(Meth)acrylate polymer (B)> Polymer 1B: polymer having an alicyclic skeleton (weight-average molecular weight Mw: 8,400) Polymer 2B: polymer having an alicyclic skeleton (weight-average molecular weight Mw: 37,000)

[0233] Next, other materials used in the photocurable resin composition will be described. Photopolymerization initiator (C): photoradical polymerization initiator (1-hydroxycyclohexyl phenyl ketone, manufactured by IGM Resins, product name: Omnirad 184) Polymerization initiator other than photopolymerization initiator (C): Perhexa C (1,1-di(t-butylperoxy)cyclohexane, manufactured by NOF Corporation) Antioxidant (D): Antioxidant 1: Adekastab AO-412S (bis[3-(dodecylthio)propionic acid]2,2-bis[[3-(dodecylthio)-1-oxopropyloxy]methyl]-1,3-propanediyl, manufactured by ADEKA Corporation) (hereinafter also referred to as AO-412S). Antioxidant 2: Adekastab AO-60 (pentaerythritol tetrakis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate], manufactured by ADEKA Corporation) (hereinafter also referred to as AO-60) Antioxidant 3: Irganox 1076 (octadecyl 3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate), manufactured by BASF) Antioxidant 4: Irgafos 168 (tris(2,4-di-tert-butylphenyl phosphite), manufactured by BASF) Light stabilizer (E): Adekastab LA-82 (1,2,2,6,6-pentamethyl-4-piperidyl methacrylate, manufactured by ADEKA Corporation) (hereinafter also referred to as LA-82) Chain transfer agent (F): Chain transfer agent 1: Karenz MT (registered trademark) PE1 (pentaerythritol tetrakis(3-mercaptobutyrate), manufactured by Resonac Co., Ltd.) (hereinafter also referred to as PE1). Chain transfer agent 2: n-octyl mercaptan (manufactured by Kao Corporation) (hereinafter also referred to as n-OM).

[0234] Next, the materials used in the synthesis of the above polymer 1B and polymer 2B will be described. The monomer composition in each polymer is as shown in Table 4. Materials used in the synthesis of polymer 1B and polymer 2B Monomer: GM81HDA Polymerization initiator: 2,2'-azobis(2-methylpropionate)dimethyl (product name: V-601, manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.) Solvent: butyl acetate (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.)

[0235] Polymer 1B and Polymer 2B were each synthesized by the following method. 326 g of a solvent (butyl acetate) was placed in a 1 L glass four-neck round-bottom flask equipped with a stirrer. The monomers and polymerization initiator were each weighed out according to the information in Table 4. While maintaining the internal temperature of the four-neck round-bottom flask at 95°C, the weighed monomers and polymerization initiator were each added dropwise to the solvent over 360 minutes to prepare a mixed solution. Next, the mixed solution was stirred at 95°C for 270 minutes to allow the polymerization reaction to proceed. Thereafter, to polymerize the remaining monomers, a solution prepared by dissolving 2 g of polymerization initiator (V-601) in 35 g of butyl acetate was added dropwise to the mixed solution. After the dropwise addition, the mixed solution was stirred at 110°C for 120 minutes to allow the polymerization reaction to proceed. The mixture was then cooled to room temperature (23°C) over 60 minutes. After cooling, 300 g of the mixed solution was dispensed into another 5 L four-neck round-bottom flask. Next, 3,500 g of methanol was added dropwise to the dispensed mixture to obtain a precipitate. The separated precipitate was washed with 900 mL of methanol. Thereafter, the precipitate was dried in a dryer under vacuum at 85°C for 120 minutes to obtain a polymer.

[0236] The weight-average molecular weights Mw of the prepared polymers 1B and 2B were measured according to the following <Method for measuring weight-average molecular weight Mw>. The results are shown in Table 4. <Method for measuring weight-average molecular weight Mw> Using gel permeation chromatography (GPC), the weight-average molecular weight Mw of each polymer dissolved in a mobile phase was measured under the following conditions. Column: Two connected PLgel 5 μm MIXED-D, 300 × 7.5 mm (Agilent Technologies) Column temperature: 40°C Mobile phase: HPLC-grade tetrahydrofuran [containing stabilizer] (Fujifilm Wako Pure Chemical Industries, Ltd.) Flow rate: 1.0 mL / min Injection volume: 100 μL Detection method: Differential refractive index detection Column calibration: Monodisperse polystyrene (product name: EasiCal Type PS-1 Polystyrene, Agilent Technologies) Molecular weight calibration: Relative calibration method (polystyrene equivalent) Pump device: KP-22-13S dual pump (Flom Co., Ltd.) Automatic injection device: 717plus (Nihon Waters K.K.) Detector: Differential refractive index detector (product name: RI-101, Shodex)

[0237] Examples 1B to 5B The components were blended to obtain the formulations shown in Table 3, to obtain liquid photocurable resin compositions.

[0238] The photocurable resin composition was prepared as follows: Each component was placed in a light-shielding mixer. While maintaining the temperature inside the mixer at 60°C, the components were mixed and uniformly dissolved to obtain a photocurable resin composition.

[0239] Next, the physical properties of the photocurable resin compositions obtained in each example were measured by the following methods. The measurement results are shown in Table 3.

[0240] <Viscosity Measurement> The viscosity of the photocurable resin composition was measured using an E-type viscometer (product name: TVE-25L, manufactured by Toki Sangyo Co., Ltd.) at a temperature of 25°C and 2.5 rpm. The cone rotor was appropriately selected from 1°34' x R24, 3° x R14, and 3° x R9.7 depending on the viscosity of the photocurable resin composition of each example. The results are shown in Table 3.

[0241] <Measurement of Humidity Swelling Ratio α1> For cured films prepared using the photocurable resin composition of each example according to the <Cured Film Preparation Conditions> below, the humidity swelling ratio α1 was measured according to the <Humidity-Conditioned Thermomechanical Analysis (Humidity-Conditioned TMA)> below.

[0242] <Conditions for producing cured film> A 100 μm thick, 100 mm × 100 mm PET film (without release treatment, manufactured by Teijin Limited, product name: Melinax S) and a 500 μm thick, 100 mm × 100 mm silicone sheet (material: silicone rubber, hardness: 50 degrees) with a 50 mm diameter circular hole were placed in this order on a 2.0 mm thick, 100 mm × 100 mm alkali-free glass sheet (product name: JIS R 3202, glass plate thread surface, manufactured by Test Piece Co., Ltd.). After filling the circular hole in the silicone sheet with a photocurable resin composition, a 100 μm thick, 100 mm x 100 mm PET film (without release treatment, manufactured by Teijin Limited, product name: Melinax S) and a 2.0 mm thick, 100 mm x 100 mm alkali-free glass (product name: JIS R 3202 glass plate thread surface, manufactured by Test Piece Co., Ltd.) were placed on top of it in this order. It was confirmed that no air bubbles were present. Hereinafter, the PET film and silicone sheet placed on the alkali-free glass, the circular hole in the silicone sheet filled with photocurable resin, and the PET film and alkali-free glass placed on top of that may be referred to as a laminate. The above-mentioned laminate was placed on a SUS lab jack, and the height of the SUS lab jack was adjusted. The photocurable resin composition was irradiated from above the alkali-free glass with LED light having a wavelength of 405 nm at 810 mW for 3 minutes 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 laminate was then turned over and irradiated with LED light having a wavelength of 405 nm at 810 mW for an additional 3 minutes. After irradiation with 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 alkali-free glass and silicone sheet to obtain a cured film of the photocurable resin composition. The irradiation intensity of the LED light was measured using an ultraviolet integrating actinometer (product name: UIT-250, manufactured by Ushio Inc.).

[0243] <Humidity-Conditioned Thermomechanical Analysis (Humidity-Conditioned TMA)> The cured film was cut into a strip of 5 mm width and 15 mm length to prepare a test piece. Using a humidity-conditioned thermomechanical analysis (humidity-conditioned TMA), the test piece was subjected to humidity-conditioned thermomechanical analysis in the following order of <Humidity-Conditioned TMA Measurement Conditions> and <Humidity-Conditioned TMA Measurement Steps>.

[0244] <Measurement conditions for humidity-controlled TMA> Apparatus: Thermomechanical analyzer (product name: TMA 4000SE, manufactured by NETZSCH Japan) Test mode: Tensile mode Load: 5 gf Chuck distance: 10 mm Atmosphere: Nitrogen atmosphere Temperature: 65°C (constant)

[0245] <Measuring steps for humidity-conditioned TMA> The following steps S1 to S5 were performed in succession. The humidity swelling rate in the following humidity increasing step was designated as humidity swelling rate α1 [%]. The humidity swelling rate in the following humidity decreasing step was designated as humidity swelling rate α2 [%]. (S1) A process of maintaining humidity at 0% RH for 30 minutes. (S2) A process of increasing humidity from 0% RH to 90% RH at a humidity increasing rate of 5% RH / min (humidification step). (S3) A process of maintaining humidity at 90% RH for 150 minutes. (S4) A process of decreasing humidity from 90% RH to 0% RH at a humidity decreasing rate of 5% RH / min (humidification step). (S5) A process of maintaining humidity at 0% RH for 55 minutes.

[0246] <Measurement of Humidity Swelling Ratio α2> For cured films produced using the photocurable resin composition of each example according to the above <Cured Film Production Conditions>, the humidity swelling ratio α2 was measured according to the above <Humidity-Conditioned Thermomechanical Analysis (Humidity-Conditioned TMA)>.

[0247] <Measurement of Water Absorption> The optical molded body was produced using the photocurable resin composition of each example according to the <Conditions for Producing Optical Molded Body> below, and the water absorption was measured according to the <Measurement of Water Absorption> below.

[0248] <Optical Molded Body Production Conditions> An optical molded body was produced from a photocurable resin composition using a tape molding method according to the following <Tape Molding Conditions>. A pair of glass molds was placed at a predetermined distance. Tape was attached circumferentially to the outer peripheral surfaces of the glass molds to seal the space between the pair of glass molds. Next, an injection nozzle was inserted into the sealed space, and the photocurable resin composition was injected and filled into the sealed space through the injection nozzle. At this time, care was taken to avoid introducing air bubbles into the sealed space. Thereafter, with the concave surfaces of the pair of glass molds facing 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 from above the pair of glass molds with LED light having a wavelength of 405 nm at 810 mW for 3 minutes using the LED light irradiation device. Next, the pair of glass molds were turned over so that the convex surfaces of the pair of glass molds faced the LED light irradiation device. Subsequently, with the convex surfaces of the pair of glass molds facing the LED light irradiation device, the photocurable resin composition was irradiated with LED light having a wavelength of 405 nm at 810 mW for 3 minutes from above the pair of glass molds using the LED light irradiation device. After irradiating with LED light, the cured product of the photocurable resin composition was allowed to cool at 23°C for 30 minutes. After cooling, the tape was removed and the product was released from the glass mold to obtain an optical molded body. The irradiation intensity of the LED light was measured using an ultraviolet integrating actinometer (product name: UIT-250, manufactured by Ushio Inc.). <Tape molding conditions> A pair of glass molds Spherical glass mold A and spherical glass mold B were arranged so that the center line of spherical glass mold A overlapped with the center line of spherical glass mold B and the concave surface of spherical glass mold A faced the convex surface of spherical glass mold B. Spherical glass mold A: Convex surface radius of curvature: 243 mm, concave surface radius of curvature: 253 mm, thickness: 4.8 mm, diameter: 81 mmφ, double-sided polished spherical glass mold. Spherical glass mold B: Convex surface radius of curvature: 250 mm, concave surface radius of curvature: 216 mm, thickness: 3.6 mm, diameter: 81 mmφ, double-sided polished spherical glass mold. Spacing between glass molds: 3 mm Tape: SLION TAPE 6263, manufactured by Sliontec

[0249] <Water Absorption Measurement> The optical molded body obtained from the photocurable resin composition of each example was dried in a dry box at a temperature of 23°C and a relative humidity of 5% or less for 16 hours. The pre-test mass of the optical molded body was then measured. The optical molded body was then left in a thermo-hygrostat chamber at a temperature of 65°C and a relative humidity of 90% for 504 hours. The optical molded body was then removed from the thermo-hygrostat chamber, and the post-test mass of the optical molded body was measured. The water absorption of the optical molded body was then calculated using the following formula (1): Formula (1): Water absorption = {(post-test mass) - (pre-test mass)} / (pre-test mass) x 100

[0250] <Method for Measuring Haze Value> For each photocurable resin composition, a cured film was prepared according to the following <Cured Film Preparation Conditions 2>, and the haze value of the film was measured in accordance with JIS K 7136:2000 at a thickness of 3.0 mm.

[0251] <Cured Film Preparation Condition 2> 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 was placed on a 0.7 mm thick, 50 mm x 50 mm alkali-free glass (product name: JIS R 3202, glass plate, filament surface, manufactured by Test Piece Co., Ltd.). The circular hole in the silicone sheet was filled with a photocurable resin composition, and then a 0.7 mm thick, 50 mm x 50 mm alkali-free glass (product name: JIS R 3202, glass plate, filament surface, manufactured by Test Piece Co., Ltd.) was further placed on top of it. At this time, it was confirmed that no air bubbles were present. Hereinafter, the product obtained by placing a silicone sheet on the alkali-free glass, filling the circular hole in the silicone sheet with a photocurable resin composition, and then further placing alkali-free glass on top of that may be referred to as a laminate. The above-mentioned laminate was placed on a SUS lab jack, and the height of the SUS lab jack was adjusted. The photocurable resin composition was irradiated from above the alkali-free glass with LED light having a wavelength of 405 nm at 810 mW for 3 minutes 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 laminate was then turned over and irradiated with LED light having a wavelength of 405 nm at 810 mW for an additional 3 minutes. After irradiation with 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 alkali-free glass and silicone sheet to obtain a cured film of the photocurable resin composition. The irradiation intensity of the LED light was measured using an ultraviolet integrating actinometer (product name: UIT-250, manufactured by Ushio Inc.).

[0252] <Evaluation of Presence or Absence of Cracks> Optical molded bodies were produced using the photocurable resin composition of each example according to the above <Optical Molded Body Production Conditions>. An AR film was vapor-deposited onto the produced optical molded body according to the following <AR Film Vapor Deposition Method>. Next, the following <Environmental Test> was performed on the optical molded body on which the AR film was vapor-deposited. Thereafter, the appearance of the AR film of the optical molded body was visually observed to evaluate the presence or absence of cracks. This evaluation was performed with n=15. A was assigned to a case where the number of samples in which cracks occurred in the AR film of the optical molded body was 0; B was assigned to a case where the number of samples in which cracks occurred in the AR film of the optical molded body was 1 to 3; and C was assigned to a case where the number of samples in which cracks occurred in the AR film of the optical molded body was 4 or more.

[0253] <Method of depositing AR film> The size of the optical molded body was adjusted to a diameter of 75 mm. An AR film was deposited on the convex surface of the optical molded body whose size had been adjusted. The AR film was deposited using an AR deposition device (manufactured by OPTOTECH). ZrO ２ Film 32.5nm, SiO ２ Film 49.7nm, TiO ２ Film 225.3 nm, SiO ２ A 164.5 nm thick film and a 7.0 nm thick hydrophobic film were deposited in this order. During deposition, the temperature was 65±5°C and the vacuum was 5.0×10 －４ The pressure was controlled to be equal to or less than Pa. The hydrophobic film used was Excel CV Pill 1110 (manufactured by OPTOTECH).

[0254] <Environmental Test> The optical molded body on which the AR film was deposited was placed in a thermo-hygrostat chamber at a temperature of 65° C. and a relative humidity of 90% RH. After 504 hours had passed since being placed in the thermo-hygrostat chamber, the optical molded body was taken out of the thermo-hygrostat chamber.

[0255] Comparative Example 1B The resin composition of Comparative Example 1B was prepared by the following method. First, the raw materials were weighed out to obtain the formulation of Comparative Example 1B shown in Table 3. Using the weighed raw materials, a mixed monomer solution (hereinafter also referred to as a monomer solution) described in JP 2019-035015 A (hereinafter also referred to as Publication 1) and a polymerization initiator solution (hereinafter also referred to as an initiator solution) described in Publication 1 were obtained according to the method described in Example 1 of Publication 1. The monomer solution was a solution obtained by dissolving MMA, phMI, chMI, and n-OM described in Table 3 in a meta-xylene solvent. The initiator solution was a solution obtained by dissolving Perhexa C described in Table 3 in a meta-xylene solvent. Next, the mixed monomer solution and the initiator solution were mixed and polymerized under the polymerization conditions described in Example 1 of Publication 1 to obtain a polymerization solution containing the polymer described in Publication 1 (the polymer of Comparative Example 1B). Next, 0.1 parts by mass of Irganox 1076 and 0.05 parts by mass of Irgafos 168 were added to the obtained polymerization solution with stirring, relative to 100 parts by mass of the polymer contained in the solution. The obtained polymer of Comparative Example 1B was dissolved in ethyl acetate and then reprecipitated with ethanol twice. Next, the resin composition of Comparative Example 1B was obtained by drying under reduced pressure at a temperature of 60 ° C., a pressure reduced from atmospheric pressure to 100 kPa, and drying for 72 hours. Note that when the mixed monomer solution and the initiator solution are mixed, the polymerization reaction begins immediately after mixing, so viscosity measurement was not performed on the resin composition of Comparative Example 1B.

[0256] <Measurement of Humidity Swelling Ratio α1> A cured film was produced using the resin composition of Comparative Example 1B according to the <Cured Film Production Conditions for Comparative Example 1B> below, and the humidity swelling ratio α1 was measured according to the <Humidity-Conditioned Thermomechanical Analysis (Humidity-Conditioned TMA)> described above.

[0257] <Cured film production conditions for Comparative Example 1B> The resin composition of Comparative Example 1B was heated and melted at 260°C for 3 minutes. Next, 90 g of the molten resin composition was placed in a mold (product dimensions: length 30 mm x width 30 mm x thickness 1 mmt) and dried under reduced pressure at 120°C, reduced pressure from atmospheric pressure by 90 kPa, and dried for 18 hours. Next, using a heat press device, the resin composition placed in the mold was heat-pressed at 260°C, a pressure of 5 MPa, and 1 minute. Next, the resin composition placed in the mold was heat-pressed a total of 17 times at 260°C, a pressure of 10 MPa, and 1 minute. Next, the resin composition placed in the mold was allowed to cool at 23°C for 30 minutes. After cooling, the cured resin composition was released from the mold to obtain a cured film of Comparative Example 1B.

[0258] <Measurement of Humidity Swelling Ratio α2> For a cured film produced using the resin composition of Comparative Example 1B according to the above <Cured Film Production Conditions for Comparative Example 1B>, the humidity swelling ratio α2 was measured according to the above <Humidity-Conditioned Thermomechanical Analysis (Humidity-Conditioned TMA>>.

[0259] <Measurement of Water Absorption Rate> An optical molded body was produced using the resin composition of Comparative Example 1B according to the <Conditions for producing optical molded body of Comparative Example 1B> below, and the water absorption rate was measured according to the above <Measurement of Water Absorption Rate>.

[0260] <Conditions for producing an optical molded body of Comparative Example 1B> The resin composition of Comparative Example 1B was heated and melted at 260°C for 3 minutes. Next, 30 g of the molten resin composition was placed in a mold (product dimensions: length 30 mm x width 30 mm x thickness 3 mmt) and dried under reduced pressure at 120°C, reduced from atmospheric pressure by 90 kPa, and for 18 hours. Next, using a heat press device, the resin composition placed in the mold was heat-pressed at 260°C, 5 MPa, and 1 minute. Next, the resin composition placed in the mold was heat-pressed a total of 17 times at 260°C, 10 MPa, and 1 minute. Next, the resin composition placed in the mold was allowed to cool at 23°C for 30 minutes. After cooling, the cured resin composition was released from the mold to obtain an optical molded body of Comparative Example 1B.

[0261] <Method for measuring haze value> For the resin composition of Comparative Example 1B, a cured film was produced according to the above <Conditions for producing a cured film of Comparative Example 1B>, and the haze value at a thickness of 1 mm was measured in accordance with JIS K 7136:2000.

[0262] <Evaluation of Presence or Absence of Cracks> An optical molded body was produced using the resin composition of Comparative Example 1B according to the above <Optical Molded Body Production Conditions of Comparative Example 1B>. An AR film was vapor-deposited onto the produced optical molded body according to the above <AR Film Vapor Deposition Method>. Next, the above <Environmental Test> was performed on the optical molded body on which the AR film was vapor-deposited. Thereafter, the appearance of the AR film of the optical molded body was visually observed to evaluate the presence or absence of cracks. This evaluation was performed with n=15. A was assigned to a case where the number of samples in which cracks occurred in the AR film of the optical molded body was 0; B was assigned to a case where the number of samples in which cracks occurred in the AR film of the optical molded body was 1 to 3; and C was assigned to a case where the number of samples in which cracks occurred in the AR film of the optical molded body was 4 or more.

[0263]

[0264]

[0265] This application claims priority based on Japanese Patent Application Nos. 2024-053413 and 2024-053428, filed March 28, 2024, the disclosures of which are incorporated herein in their entirety by reference.

Claims

1. A photocurable resin composition comprising: (A) a (meth)acrylate monomer having an alicyclic skeleton; (B) a (meth)acrylate polymer having an alicyclic skeleton; and (C) a photopolymerization initiator.

2. The photocurable resin composition according to claim 1, wherein the (meth)acrylate polymer (B) has a weight average molecular weight Mw of 3,000 or more and 5,000,000 or less in terms of polystyrene as measured by gel permeation chromatography (GPC).

3. The photocurable resin composition according to claim 2, wherein the weight average molecular weight Mw of the (meth)acrylate polymer (B) is 10,000 or more.

4. The photocurable resin composition according to any one of claims 1 to 3, wherein a cured film prepared according to the following <Cured Film Preparation Conditions> has a humidity swelling ratio α1 of 0.35% or less, as measured by the following <Humidity-Conditioned Thermomechanical Analysis (Humidity-Conditioned TMA)>. <Cured Film Preparation Conditions> A 100 μm-thick, 100 mm x 100 mm PET film and a 500 μm-thick, 100 mm x 100 mm silicone sheet (material: silicone rubber, hardness: 50 degrees) with a 50 mmφ circular hole were placed in this order on a 2.0 mm-thick, 100 mm x 100 mm alkali-free glass sheet, the circular hole was filled with the photocurable resin composition, and then the 100 μm-thick, 100 mm x 100 mm PET film and the 2.0 mm-thick, 100 mm x 100 mm alkali-free glass sheet were placed on top of the 100 μm-thick, 100 mm x 100 mm PET film and the 2.0 mm-thick, 100 mm x 100 mm alkali-free glass sheet. The above-mentioned items are further placed in this order, and this is placed on an SUS lab jack to adjust the height. One of the alkali-free glasses is irradiated with LED light having a wavelength of 405 nm at 810 mW for 3 minutes onto the photocurable resin composition, and then the glass is turned over and irradiated with LED light having a wavelength of 405 nm at 810 mW for 3 minutes. The glass is then allowed to cool at 23°C for 30 minutes, and the cured product of the photocurable resin composition is released from the alkali-free glass, the PET film, and the silicone sheet to obtain a cured film. <Humidity-Conditioned Thermomechanical Analysis (Humidity-Conditioned TMA)> The cured film was cut into a strip having a width of 5 mm and a length of 15 mm to prepare a test piece. The test piece was subjected to humidity-conditioned thermomechanical analysis (humidity-conditioned TMA) in a tensile mode with a load of 5 gf, a chuck distance of 10 mm, in a nitrogen atmosphere, and at a constant temperature of 65°C. The following steps were successively performed: maintaining the test piece at a humidity of 0% RH for 30 minutes, increasing the humidity from 0% RH to 90% RH at a humidity increase rate of 5% RH / min (humidity increase step), maintaining the test piece at a humidity of 90% RH for 150 minutes, decreasing the humidity from 90% RH to 0% RH at a humidity decrease rate of 5% RH / min (humidity decrease step), and maintaining the test piece at a humidity of 0% RH for 55 minutes. The humidity swelling ratio in the humidity increase step was designated as the humidity swelling ratio α1.

5. A photocurable resin composition comprising: (A) a (meth)acrylate monomer having an alicyclic skeleton; (B) a (meth)acrylate polymer having an alicyclic skeleton; and (C) a photopolymerization initiator, wherein a cured film produced according to the following <Cured Film Production Conditions> has a humidity swelling ratio α1 of 0.35% or less, as measured according to the following <Humidity-Controlled Thermomechanical Analysis (Humidity-Controlled TMA)>. <Cured Film Production Conditions> A 100 μm thick, 100 mm x 100 mm PET film and a 500 μm thick, 100 mm x 100 mm silicone sheet (material: silicone rubber, hardness: 50 degrees) with a 50 mm diameter circular hole were placed in this order on a 2.0 mm thick, 100 mm x 100 mm alkali-free glass sheet, and the circular hole was filled with the photocurable resin composition. Then, a 100 μm thick, 100 mm x 100 mm PET film and a 2.0 mm thick, 100 mm x 100 mm alkali-free glass sheet were placed on top of the 100 μm thick, 100 mm x 100 mm PET film and the 2.0 mm thick, 100 mm x 100 mm alkali-free glass sheet. The above-mentioned items are further placed in this order, and this is placed on an SUS lab jack to adjust the height. One of the alkali-free glasses is irradiated with LED light having a wavelength of 405 nm at 810 mW for 3 minutes onto the photocurable resin composition, and then the glass is turned over and irradiated with LED light having a wavelength of 405 nm at 810 mW for 3 minutes. The glass is then allowed to cool at 23°C for 30 minutes, and the cured product of the photocurable resin composition is released from the alkali-free glass, the PET film, and the silicone sheet to obtain a cured film. <Humidity-Conditioned Thermomechanical Analysis (Humidity-Conditioned TMA)> The cured film was cut into a strip having a width of 5 mm and a length of 15 mm to prepare a test piece. The test piece was subjected to humidity-conditioned thermomechanical analysis (humidity-conditioned TMA) in a tensile mode with a load of 5 gf, a chuck distance of 10 mm, in a nitrogen atmosphere, and at a constant temperature of 65°C. The following steps were successively performed: maintaining the test piece at a humidity of 0% RH for 30 minutes, increasing the humidity from 0% RH to 90% RH at a humidity increase rate of 5% RH / min (humidity increase step), maintaining the test piece at a humidity of 90% RH for 150 minutes, decreasing the humidity from 90% RH to 0% RH at a humidity decrease rate of 5% RH / min (humidity decrease step), and maintaining the test piece at a humidity of 0% RH for 55 minutes. The humidity swelling ratio in the humidity increase step was designated as the humidity swelling ratio α1.

6. The photocurable resin composition according to claim 5, wherein the humidity swelling rate in the humidity decreasing step is a humidity swelling rate α2, and in a cured film produced in accordance with the <cured film production conditions>, the humidity swelling rate α2 measured in accordance with the <humidity-conditioned thermomechanical analysis (humidity-conditioned TMA)> is 0.30% or less.

7. The photocurable resin composition according to claim 5 or 6, wherein an optical molded body produced according to the <Optical Molded Body Production Conditions> below has a water absorption of 0.34% or less as measured according to the <Water Absorption Measurement> below. <Optical Molded Body Production Conditions> A pair of glass molds are placed at a predetermined distance, tape is attached circumferentially to the outer peripheral surfaces of the pair of glass molds to seal the space between the pair of glass molds, the photocurable resin composition is injected through an injection nozzle to fill the sealed space, and the photocurable resin composition is irradiated from above the pair of glass molds with LED light having a wavelength of 405 nm at 810 mW for 3 minutes, then the glass molds are turned over and irradiated with LED light having a wavelength of 405 nm at 810 mW for 3 minutes, followed by cooling at 23°C for 30 minutes, and then the tape is removed and the optical molded body is obtained by releasing the glass molds from the pair of glass molds. <Water Absorption Measurement> The optical molded body is dried under conditions of a temperature of 23°C and a relative humidity of 5% RH or less for 16 hours, the pre-test mass of the optical molded body is measured, the optical molded body is left in a thermo-hygrostat chamber under conditions of a temperature of 65°C and a relative humidity of 90% RH for 504 hours, the post-test mass of the optical molded body taken out of the thermo-hygrostat chamber is measured, and the water absorption is calculated from the following formula (1): Formula (1): Water absorption = {(post-test mass) - (pre-test mass)} / (pre-test mass) x 100 8. The photocurable resin composition according to any one of claims 5 to 7, wherein the (meth)acrylate polymer (B) has a weight average molecular weight Mw of 3,000 or more and 5,000,000 or less in terms of polystyrene as measured by gel permeation chromatography (GPC).

9. The photocurable resin composition according to claim 8, wherein the weight average molecular weight Mw of the (meth)acrylate polymer (B) is 3,000,000 or less.

10. A photocurable resin composition according to any one of claims 1 to 9, wherein the content of the (meth)acrylate polymer (B) is 0.5 parts by mass or more and 90 parts by mass or less when the content of the (meth)acrylate monomer (A) is 100 parts by mass.

11. The photocurable resin composition according to any one of claims 1 to 10, wherein the (meth)acrylate monomer (A) and the (meth)acrylate polymer (B) have one or more skeletons selected from the group consisting of an adamantane skeleton, a norbornane skeleton, a dicyclopentadiene skeleton, an isobornyl skeleton, and a cyclohexane skeleton.

12. The photocurable resin composition according to any one of claims 1 to 11, wherein the (meth)acrylate monomer (A) is monofunctional or difunctional or higher.

13. The photocurable resin composition according to any one of claims 1 to 12, further comprising a monofunctional or di- or higher functional (meth)acrylate monomer (excluding the (meth)acrylate monomer (A)).

14. A photocurable resin composition according to any one of claims 1 to 13, wherein the viscosity of the photocurable resin composition measured using an E-type viscometer at a temperature of 25°C and a rotation speed of 2.5 rpm is 110 mPa·s or more and 5000 mPa·s or less.

15. The photocurable resin composition according to any one of claims 1 to 14, wherein a cured film prepared in accordance with the following <Cured Film Preparation Conditions> has a haze value of less than 1.0% at a thickness of 3.0 mm, as measured in accordance with JIS K 7136:2000. <Conditions for Producing a Cured Film> 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 was placed on a 0.7 mm thick, 50 mm x 50 mm alkali-free glass sheet. The circular hole was filled with the photocurable resin composition, and then a 0.7 mm thick, 50 mm x 50 mm alkali-free glass sheet was placed on top of the silicone-free glass sheet. The height was adjusted by placing this on a stainless steel lab jack. The photocurable resin composition was irradiated with LED light having a wavelength of 405 nm at 810 mW from above the alkali-free glass sheet for 3 minutes, then turned over and irradiated with LED light having a wavelength of 405 nm at 810 mW for 3 minutes. The glass sheet was then allowed to cool at 23°C for 30 minutes, and the cured product of the photocurable resin composition was released from the alkali-free glass sheet and the silicone sheet to obtain a cured film.

16. The photocurable resin composition according to any one of claims 1 to 15, further comprising a chain transfer agent.

17. The photocurable resin composition according to any one of claims 1 to 16, further comprising an antioxidant.

18. The photocurable resin composition according to any one of claims 1 to 17, wherein the photopolymerization initiator (C) includes a photoradical polymerization initiator.

19. The photocurable resin composition according to any one of claims 1 to 18, further comprising a light stabilizer.

20. A photocurable resin composition according to any one of claims 1 to 19, which can be used in a casting method.

21. The photocurable resin composition according to any one of claims 1 to 20, 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 cross reality devices (xR lenses), and lenses for head-mounted displays (HMD lenses).

22. A cured product of the photocurable resin composition according to any one of claims 1 to 21.

23. An optical molded body comprising a cured product of the photocurable resin composition according to any one of claims 1 to 21.

24. The optical molded body of claim 23, wherein the optical molded body comprises a lens.

25. The optical molded body according to claim 24, wherein the lens comprises 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).

26. The optical molded body according to any one of claims 23 to 25, wherein the maximum thickness is 20.0 mm or less.

27. The optical molded body according to any one of claims 23 to 26, wherein the maximum thickness is 1.0 mm or more.

Images