Hardening composition, hardened material

Abstract

To provide a curable composition that has a high refractive index and reflow resistance and, when cured, gives a cured product while minimizing the attachment of foreign matter to the cured product itself and its peripheral members; and to provide a cured product thereof.SOLUTION: A curable composition contains methacrylate having a fluorene structure, methacrylate having a biphenyl or phenoxyphenyl structure, and a polymerization initiator that is liquid at 25°C.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to a curable composition and a cured product of the curable composition. [Background technology]

[0002] Surface mounting technology is advancing rapidly, especially in small devices such as mobile phones and laptops. With the spread of lightweight, high-performance electronic devices, electronic components are also rapidly becoming smaller. The lens is one of them, and there is a demand for miniaturization, including camera lenses, and the refractive index is High thermal conductivity, low Abbe number, high transparency and heat resistance, and low adhesion of foreign matter are required. For example, a camera module for a mobile phone usually contains multiple lenses with different refractive indices. For high refractive index lenses, fluorene polyester resin is mainly used. However, since fluorene-based polyester resin is a thermoplastic resin, it is difficult to apply solder to the resin. It has the disadvantage of being easily melted by heat during flow (poor heat resistance and reflow resistance).

[0003] Resin using (meth)acrylate with fluorene structure to improve reflow resistance A method of introducing a cross-linked structure into the material is known, and it has a high refractive index and excellent transparency. Therefore, it is considered to be useful for various plastic lenses (Patent Documents 1 to 3). [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2008-94987 [Patent Document 2] Japanese Patent Application Laid-Open No. 2011-126991 [Patent Document 3] Japanese Patent Application Laid-Open No. 2012-82387 Summary of the Invention [Problem to be solved by the invention]

[0005] However, the methods of Patent Documents 1 to 3 have insufficient reflow resistance, and vapor formation from the lens These particles can become foreign matter and contaminate the lens itself and its surrounding parts. In applications where visibility is required to be higher than ever before, materials that can attract such foreign matter are The material is not suitable for use.

[0006] The present invention has been made to improve the above-mentioned problems, and provides a high refractive index, high transparency, and It has reflow resistance and when cured, it has little adhesion of foreign matter to the cured product itself and surrounding components. The present invention aims to provide a curable composition and a cured product thereof. [Means for solving the problem]

[0007] The present invention has the following aspects. [1] (Meth)acrylate, biphenyl or phenoxy fluorene structure A (meth)acrylate having a phenyl structure and a polymerization initiator that is liquid at 25°C are used. A curable composition comprising: [2] The (meth)acrylate having a fluorene structure is a compound represented by the following formula (1): The curable composition according to [1], which is a compound. [ka] In formula (1), R 1 , R 2 , R 3 , R 4 are each independently a hydrogen atom or a methyl group, m represents an integer of 0 to 5; n represents an integer of 0 to 5; [3] The (meth)acrylate having a biphenyl or phenoxyphenyl structure Phenylphenoxyalkyl (meth)acrylate or phenoxyphenyl alkyl ( The curable composition according to [1] or [2], wherein the compound is a methacrylate. [4] Any of [1] to [3] containing a trifunctional or higher polyfunctional (meth)acrylate. The curable composition according to claim 1. [5] The molecular weight of the radical generated from the polymerization initiator which is liquid at 25°C is 95 The curable composition according to any one of [1] to [4] below: [6] The curable composition according to any one of [1] to [5], which contains an antioxidant. [7] The total mass of all structural units constituting the curable composition is Any one of [1] to [6], wherein the proportion of (meth)acrylate is 15 to 95 mass%. The curable composition according to claim 1. [8] Biphenyl or phenoxy based on the total mass of all structural units constituting the curable composition The proportion of (meth)acrylate having an alkoxyphenyl structure is 3 to 80 mass %. [1] The curable composition according to any one of items [7] to [7]. [9] The total mass of all structural units constituting the curable composition is acrylate (the fluorene structure, biphenyl structure or phenoxyphenyl structure [1] to [8], wherein the proportion of (excluding (meth)acrylates having The curable composition according to any one of claims 1 to 10.

[10] The total mass of all the constituent units constituting the curable composition is liquid at 25°C. [1] to [9], wherein the proportion of the polymerization initiator is 0.1 to 10 mass %. The above curable composition.

[11] A cured product of the curable composition according to any one of [1] to

[10] .

[12] A lens made of the cured product according to

[11] . [Effects of the Invention]

[0008] According to the present invention, the composition has reflow resistance, and when cured, the composition does not cause any abnormality to the cured product itself or to surrounding components. A curable composition that forms a cured product with little adhesion of other objects, and has reflow resistance and is capable of bonding itself to surroundings A cured product can be provided that is less susceptible to foreign matter adhering to components. DETAILED DESCRIPTION OF THE INVENTION

[0009] Hereinafter, embodiments of the present invention will be described in detail. In the present invention, "(meth)acrylate" refers to the total of acrylates or methacrylates. It is a title. The "~" symbol indicates a range of values, and includes the values ​​before and after it as the lower and upper limits. This means:

[0010] <Curable composition> The curable composition of the present invention comprises a (meth)acrylate having a fluorene structure, a biphenyl or (meth)acrylate having a phenoxyphenyl structure and liquid at 25°C The polymerization initiator is

[0011] (Meth)acrylates having a fluorene structure are materials for increasing the refractive index. It has a (meth)acrylate moiety to provide reflow resistance and hardens by radical reaction. As the (meth)acrylate having a fluorene structure, there are known Among these, those with high refractive index and glass transition temperature after curing can be used. The compound of the following formula (1) is preferred because it has a lower viscosity than the compound of the present invention. [ka]

[0012] In formula (1), R 1 , R 2 , R 3 , R 4 are each independently a hydrogen atom or a methyl group, m represents an integer of 0 to 5, and n represents an integer of 0 to 5. Among them, the refractive index of the cured product is high. Because of this and the increased reactivity, 1 and R 4 is preferably a hydrogen atom. From the viewpoint of formability, m and n are each preferably 1 or 2, and more preferably 1. In addition, R 2 and R 3 From the viewpoint of formability, it is better that hydrogen atoms are also present. This is the preferred form.

[0013] (Meth)acrylates having a biphenyl or phenoxyphenyl structure are fluorene Improved solubility, moldability, and high solubility of (meth)acrylate having the structure in curable composition It is used from the viewpoint of adjusting the refractive index, and a conventionally known compound can be used. Examples of (meth)acrylates having a phenyl structure include ortho-phenylpheno Meta-phenylphenoxyethyl (meth)acrylate, meta-phenylphenoxyethyl (meth)acrylate para-phenylphenoxyethyl (meth)acrylate, ortho-phenylphenoxy Dipropyl (meth)acrylate, meta-phenylphenoxypropyl (meth)acrylate acrylate, para-phenylphenoxypropyl (meth)acrylate, ortho-phenylphenoxypropyl Phenoxybutyl (meth)acrylate, meta-phenylphenoxybutyl (meth)acrylate phenylphenoxy acrylate, para-phenylphenoxybutyl (meth)acrylate, etc. Alkyl (meth)acrylate, ortho-phenylphenoxyethoxyethyl (meth)acrylate Acrylate, meta-phenylphenoxyethoxyethyl (meth)acrylate, para-phenylphenoxyethoxyethyl (meth)acrylate Phenylphenoxyalkoxy such as phenylphenoxyethoxyethyl (meth)acrylate Alkyl (meth)acrylate, ortho-biphenylmethyl (meth)acrylate, meth -Biphenylmethyl (meth)acrylate, para-biphenylmethyl (meth)acrylate ortho-biphenylethyl (meth)acrylate, meta-biphenylethyl (meth)acrylate Acrylate, para-biphenylethyl (meth)acrylate, ortho-biphenylpropionate Para-biphenylpropyl (meth)acrylate, meta-biphenylpropyl (meth)acrylate, para-biphenylpropyl (meth)acrylate Phenylpropyl (meth)acrylate, ortho-biphenylbutyl (meth)acrylate butyl (meth)acrylate, para-biphenyl butyl (meth)acrylate Among these, biphenyl alkyl (meth)acrylates such as acrylates can be mentioned. Phenylphenoxyalkyl (meth)acrylate, phenylphenoxyalkoxy Alkyl (meth)acrylate and biphenyl alkyl (meth)acrylate have high refractive index. From this point of view, phenylphenoxyalkyl(meth)acrylate is preferable when solubility and moldability are also taken into consideration. acrylate and phenylphenoxyalkoxyalkyl(meth)acrylate are more preferred. Phenylphenoxyethyl (meth)acrylate is more preferred. Among them, the ortho position is preferred. Furthermore, in consideration of reactivity, acrylate is preferred over methacrylate. These compounds may be used alone or in combination of two or more. stomach.

[0014] Examples of (meth)acrylates having a phenoxyphenyl structure include ortho-phenoxyphenyl. Phenoxyphenylmethyl (meth)acrylate, meta-phenoxyphenylmethyl (meth)acrylate Acrylate, para-phenoxyphenylmethyl (meth)acrylate, ortho-phenoxyphenylmethyl (meth)acrylate Phenoxyphenylethyl (meth)acrylate, meta-phenoxyphenylethyl (meth)acrylate Acrylate, para-phenoxyphenylethyl (meth)acrylate, ortho-phenoxy Diphenylpropyl (meth)acrylate, meta-phenoxyphenylpropyl (meth)acrylate Acrylate, para-phenoxyphenylpropyl (meth)acrylate, ortho-phenoxyphenyl Phenoxyphenylbutyl (meth)acrylate, meta-phenoxyphenylbutyl (meth) Acrylate, para-phenoxyphenyl butyl (meth)acrylate, ortho-phenoxyphenyl Phenoxyphenylpentyl (meth)acrylate, meta-phenoxyphenylpentyl (meth)acrylate ) acrylate, para-phenoxyphenylpentyl (meth)acrylate, ortho- Phenoxyphenylhexyl (meth)acrylate, meta-phenoxyphenylhexyl ( phenoxyphenyl hexyl (meth)acrylate, para-phenoxyphenyl hexyl (meth)acrylate, etc. Phenoxyphenyl alkyl (meth)acrylate, ortho-phenoxyphenyloxymethy (meth)acrylate, meta-phenoxyphenyloxymethyl (meth)acrylate , para-phenoxyphenyloxymethyl (meth)acrylate, ortho-phenoxyphenyl Phenoxyethyl (meth)acrylate, meta-phenoxyphenyloxyethyl (meth)acrylate p-phenoxyphenyloxyethyl (meth)acrylate, ol Meta-phenoxyphenyloxypropyl (meth)acrylate, meta-phenoxyphenyl Para-phenoxyphenyloxypropyl (meth)acrylate, para-phenoxyphenyloxypropyl (meth)acrylate meth)acrylate, ortho-phenoxyphenyloxybutyl (meth)acrylate, meth Ter-phenoxyphenyloxybutyl (meth)acrylate, para-phenoxyphenyl Phenoxyphenyloxyalkyl (meth)acrylates such as oxybutyl (meth)acrylate acrylate, ortho-phenoxyphenyl methoxyethyl (meth)acrylate, meta- Phenoxyphenyl methoxyethyl (meth)acrylate, para-phenoxyphenyl meth ethoxyethyl (meth)acrylate, ortho-phenoxyphenylethoxyethyl (meth)acrylate Acrylate, meta-phenoxyphenylethoxyethyl (meth)acrylate, para- Phenoxyphenylalkoxy such as phenoxyphenylethoxyethyl (meth)acrylate Among these, phenoxyphenyl Alkyl (meth)acrylates are preferred from the viewpoint of solubility and moldability, and phenoxyethanol is particularly preferred. Phenoxyphenylmethyl (meth)acrylate and phenoxyphenylethyl (meth)acrylate From the viewpoint of a high refractive index, phenoxyphenylmethyl (meth)acrylate is more preferable. Among the positional isomers, the meta position is more preferable. Furthermore, in consideration of reactivity, Acrylates are preferred over methacrylates. These compounds may be used alone. However, two or more types may be used in combination. In consideration of moldability and yellowing at high temperatures, phenoxyethanol is preferred. A (meth)acrylate having a diphenyl structure is more preferred.

[0015] The curable composition may contain other active energy ray-curable compounds other than those mentioned above. For example, (meth)acrylate containing an aromatic ring is used because of its high refractive index. Benzyl (meth)acrylate, phenyl (meth)acrylate, phenoxy By including these compounds, moldability can be improved. In addition, it is possible to obtain a suitable viscosity. Phenyl methacrylate and phenyl methacrylate are more preferred.

[0016] Furthermore, from the viewpoint of moldability, a fluorene structure, a biphenyl structure, or a phenoxyphenyl structure may be used. Monofunctional (meth)acrylates, bifunctional (meth)acrylates, excluding (meth)acrylates having a methyl group structure ) acrylate, a mixture of one or more trifunctional or higher multifunctional (meth)acrylates, Any commercially available hardening resin material or any other material that does not impair the object of this embodiment may be used. Other components may be added as long as they are not added to the cured product. In order to take into consideration the strength as a component and to make the cured product less likely to deform even at high temperatures, glass rolling is used. A high transition point is desirable, but to achieve this, multifunctional (meth)acrylates with three or more functional groups are used. It is preferable that the compound contains methyl methyl acrylate.

[0017] Monofunctional (meth)acrylates include methyl (meth)acrylate, ethyl (meth)acrylate, Acrylate, butyl (meth)acrylate, propyl (meth)acrylate, n-butyl butyl (meth)acrylate, i-butyl (meth)acrylate, t-butyl (meth)acrylate acrylate, hexyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, Uryl (meth)acrylate, Stearyl (meth)acrylate, Morpholyl (meth)acrylate Acrylate, 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl ( (meth)acrylate, 4-hydroxybutyl (meth)acrylate, glycidyl (meth) Acrylate, dimethylaminoethyl (meth)acrylate, diethylaminoethyl (meth)acrylate (meth)acrylate, tricyclodecane (meth)acrylate, polyethylene glycol Cyclohexyl (meth)acrylate, tetrahydrofurfuryl dicyclopentanyl (meth)acrylate, dicyclopentanyl (meth)acrylate, dicyclopentenyl Allyl (meth)acrylate, isobornyl (meth)acrylate, allyl (meth)acrylate acrylate, 2-ethoxyethyl (meth)acrylate, adamantyl (meth)acrylate, (Meth)acrylic acid and the like.

[0018] The difunctional polyfunctional (meth)acrylate is not particularly limited, but examples thereof include For example, 1,4-butanediol di(meth)acrylate, neopentyl glycol di(meth)acrylate Acrylate, 1,6-hexanediol di(meth)acrylate, 1,9-nonanedi All di(meth)acrylate, tricyclodecane dimethylol di(meth)acrylate Alkanediol di(meth)acrylates, bisphenol A ethylene oxide modified Di(meth)acrylate, bisphenol F, ethylene oxide modified di(meth)acrylate bisphenol-modified di(meth)acrylates, polyethylene glycol di(meth)acrylates, etc. acrylate, polypropylene glycol di(meth)acrylate, urethane di(meth)acrylate di(meth)acrylate, epoxy di(meth)acrylate, etc.

[0019] The trifunctional or higher polyfunctional (meth)acrylate is not particularly limited, but may be: For example, dipentaerythritol hexa(meth)acrylate, pentaerythritol tetraacetate Pentaerythritol tri(meth)acrylate, pentaerythritol tri(meth)acrylate, ditrimethicone Trimethylolpropane tetra(meth)acrylate, trimethylolpropane tri(meth)acrylate acrylate, ethylene oxide modified dipentaerythritol hexa(meth)acrylate , ethylene oxide modified pentaerythritol tetra(meth)acrylate, ethylene Ethylene oxide such as oxide-modified pentaerythritol tri(meth)acrylate Modified (meth)acrylate, ethylene oxide isocyanurate modified tri(meth)acrylate isocyanurate, ε-caprolactone-modified tris(acryloxyethyl) isocyanurate, etc. Cyanuric acid modified tri(meth)acrylate, pentaerythritol triacrylate hexyl Methylene diisocyanate urethane prepolymer, pentaerythritol triacrylate Toluene diisocyanate urethane prepolymer, dipentaerythritol pentaerythritol Urethane (meth) such as acrylate hexamethylene diisocyanate urethane prepolymer Among these, those that can increase the glass transition temperature of the cured product are In terms of curability, strength, and reflow resistance, trimethylolpropane tri(meth)acrylate Dipentaerythritol hexa(meth)acrylate, pentaerythritol tetra(meth)acrylate pentaerythritol tri(meth)acrylate and pentaerythritol tri(meth)acrylate are more preferred. stomach.

[0020] The curable composition may contain an active energy ray-curable compound other than (meth)acrylate. For example, styrene, vinyl halide, vinyl acetate, etc. Vinyl compounds, vinylidene halides, 1,3-butadiene, isoprene, chloroprene Furthermore, sulfur compounds are used to prevent discoloration during high-temperature processes. It is preferable that the cured product does not contain any yellow or nitrogen elements, and in particular, sulfur elements. From the viewpoint of uniformity of the components, it is preferable that the composition does not contain siloxane compounds or inorganic components. If the thickness is not uniform, visibility will be reduced and the surface will become brittle.

[0021] The curable composition further contains a polymerization initiator that is liquid at 25°C. Among them, liquid photopolymerization initiators (which generate radicals when irradiated with active energy rays) are particularly effective. Because it is a liquid, it can be easily applied at high temperatures, such as during reflow treatment. In the process below, even if the compound volatilizes, it is difficult for it to aggregate, resulting in a visible This makes it less likely for foreign matter to form, making it easier to ensure visibility when used in lenses, etc.

[0022] Examples of polymerization initiators that are liquid at 25°C include 2-hydroxy-2-methyl -1-phenyl-propan-1-one, methyl phenylglyoxylate, benzoylformate Methyl, phenyl(2,4,6-trimethylbenzoyl) ethyl phosphinate, 4-(dimethyl (amino)benzoic acid 2-ethylhexyl, etc. The molecular weight of the radical is more preferably 95 or less, and even more preferably 70 or less. Furthermore, from the viewpoint of yellowing, a polymerization initiator that does not contain nitrogen element or sulfur element, particularly sulfur element, is preferable. These polymerization initiators may be used alone or in combination of two or more. You may do so.

[0023] Furthermore, the curable composition contains antioxidants to prevent yellowing during high-temperature processes such as reflow. It is also a preferred embodiment to contain an agent.

[0024] Examples of antioxidants include 2,6-di-t-butylphenol, 2,6-di-t- Butyl-p-cresol, n-octadecyl-3-(3',5'-di-t-butyl-4' -hydroxyphenyl)propionate, tetrakis-[methylene-3-(3',5'- Di-t-butyl-4'-hydroxyphenyl)propionate]methane, triethylene glycol Licorbis[3-(3-t-butyl-5-methyl-4-hydroxyphenyl)propionate 1,6-hexanediol bis[3-(3,5-di-t-butyl-4-hydroxybenzoate], Phenolic antioxidants such as triphenyl phosphite; , tris-isodecyl phosphite, tris-tridecyl phosphite, tris(2,4- Phosphorus-based antioxidants such as di-t-butylphenyl) phosphite; dilauryl-3,3'- Thiodipropionate, Ditridecyl-3,3'-thiodipropionate, Dimyristyl -3,3'-thiodipropionate, distearyl-3,3'-thiodipropionate, Sulfur-based antioxidants such as pentaerythritol tetrakis (β-lauryl thiopropionate) Among these, phenol is preferred from the viewpoint of solubility in the curable composition. From the viewpoint of preventing yellowing of the cured product, phenol-based antioxidants and sulfur-based antioxidants are preferred. Among them, the antioxidants having a molecular weight of 540 are more preferable from the viewpoint of preventing the generation of foreign matter. Preferably, it is 800 or more, more preferably tetrakis-[methylene-3- (3',5'-di-t-butyl-4'-hydroxyphenyl)propionate]methane These antioxidants may be used alone or in combination of two or more. stomach.

[0025] The curable composition may contain compounds other than those mentioned above as long as they do not impair the effects of the present invention. The other components may include, for example, curing aids, various resins, rubbers, Particles, antistatic agents, plasticizers, ultraviolet absorbers, infrared absorbers, light stabilizers, leveling agents, extinguishing agents These include various additives such as foaming agents, thixotropic agents, polymerization inhibitors, release agents, fillers, fluorescent materials, pigments, and dyes. can be done.

[0026] The total mass of all structural units constituting the curable composition is The proportion of acrylate is preferably 15 to 95% by mass, more preferably 25 to 85% by mass. %, and more preferably in the range of 40 to 75 mass %. It can be made higher.

[0027] biphenyl or phenoxyethanol relative to the total mass of all structural units constituting the curable composition The proportion of the (meth)acrylate having a phenyl structure is preferably 3 to 80 mass %, more preferably The range is preferably 5 to 50% by mass, and more preferably 8 to 40% by mass. By doing so, the refractive index can be increased, and the (meth)acrylate having a fluorene structure It also improves compatibility with cellulose.

[0028] The amount of trifunctional or higher polyfunctional (meth)acrylates relative to the total mass of all structural units constituting the curable composition is Acrylate (having a fluorene structure, a biphenyl structure or a phenoxyphenyl structure) The proportion of (meth)acrylates (excluding) is preferably 50% by mass or less, more preferably 5 to 10% by mass. The content is preferably in the range of 40% by mass, and more preferably in the range of 8 to 35% by mass. While maintaining the refractive index, it is possible to increase the glass transition temperature, improve moldability, and increase the strength of the cured product. You can also raise it.

[0029] The total mass of all the structural units constituting the curable composition is a polymer that is liquid at 25°C. The proportion of the initiator is preferably 0.1 to 10% by mass, more preferably 0.2 to 8% by mass, and even more preferably The content is more preferably in the range of 0.3 to 5% by mass. This improves curability, resulting in a cured product with high strength, high transparency, and little foreign matter.

[0030] The ratio of the antioxidant to the total mass of all the constituent units constituting the curable composition is preferably is 10% by mass or less, more preferably 0.01 to 5% by mass, and even more preferably 0.1 to 3% by mass. By setting the content within the above range, yellowing due to high temperature processes such as reflow can be prevented. The effect will be higher.

[0031] <Cured product> The cured product is obtained by curing the above-mentioned curable composition. The cured product can be obtained by the following method: For example, the curable composition is formed into a predetermined shape, and then cured to form a hardened product having the predetermined shape. In this way, a cured product having a predetermined shape can be obtained. Examples of such methods include a coating method in which a curable composition is applied to a film substrate, a potting method, and the like. molding method, casting molding method, printing molding method, liquid resin injection molding method In addition, the curable composition can be cured by the LIM method, transfer molding method, etc. The polymerization method may be photopolymerization, thermal polymerization, or the like, depending on the type of polymerization initiator contained in the curable composition. Either polymerization or redox polymerization can be used.

[0032] When a curable composition is cured by photopolymerization to obtain a cured product, the wavelength of light irradiated onto the curable composition Although there are no particular limitations on the type of irradiation, it is preferable to irradiate with ultraviolet light having a wavelength of 200 to 400 nm. Specific examples of ultraviolet light sources include ultra-high pressure mercury lamps, high pressure mercury lamps, and metal halide lamps. Examples include lamps, high-power metal halide lamps, and UV-LED lamps. For example, when ultraviolet light is used, the cumulative light intensity is 100 mJ / cm 2 More than 10000m J / cm 2 It is preferable to irradiate at a dose of 500 mJ / cm or less. 2 More than 8000m J / cm 2 The more preferable illuminance is 5 mW / cm or less. 2 More than 1000mW / cm 2 Less than 10 mW / cm is preferable. 2 More than 500mW / cm 2 The following is more preferable: , 20mW / cm 2 More than 300mW / cm 2 The following is even more preferred:

[0033] After the curable composition has been photopolymerized, it is preferable to further carry out after-curing. This makes it possible to reduce the amount of unreacted (meth)acryloyl groups remaining in the cured product. This allows for increased strength of the cured product. Preferably, the temperature is 160°C for 0.1 to 24 hours, and more preferably, the temperature is 80 to 130°C for 0.2 to 10 hours. It's nice.

[0034] When the curable composition is cured by thermal polymerization to obtain a cured product, the curing conditions are not particularly limited. The curing temperature is preferably 40 to 200°C, since this makes it easier to obtain a cured product with reduced coloration. , 60 to 150°C is more preferable. In LIM and transfer molding, a curable composition is placed in a preheated mold. The curing time (heating time) when injecting and molding varies depending on the curing temperature. For example, When the curing temperature is 100°C, the time is preferably 1 to 180 seconds, more preferably 1 to 120 seconds, and On the other hand, in the case of the casting molding method, the hardening composition is placed in a mold at room temperature. The curing time when the composition is heated after injection varies depending on the curing temperature. For example, When the temperature is 70°C, the heating time is preferably 5 minutes to 5 hours, and more preferably 10 minutes to 3 hours. After the curable composition is thermally polymerized, it is preferable to further carry out after-curing. The post-cure conditions are preferably 50 to 150°C for 0.1 to 10 hours, and 70 to 1 More preferably, the temperature is 30°C for 0.2 to 5 hours.

[0035] When a curable composition is cured by redox polymerization to obtain a cured product, the curable composition is By using an initiator, it can be cured at room temperature of 5℃ to 40℃. The amount of remaining unreacted (meth)acryloyl groups can be reduced, and the strength of the cured product can be improved. The curing temperature is preferably 15 to 40°C since it can be increased as much as possible. The curable composition is less likely to gel and can be handled stably. Therefore, a reducing agent is added to the curable composition in advance. Preferably, the curing is carried out by dissolving the compound in a substance and then adding peroxide to the solution.

[0036] The refractive index of the cured product is measured at 25°C using sodium D line (589 nm). , preferably 1.590 or more, more preferably 1.595 or more, It is more preferable that the ratio is 0.596 or more. There is no particular upper limit, but it is preferably 1. By keeping the above range, various designs are possible and the range of applications is wide. do.

[0037] The glass transition point of the cured product was determined by measuring the dynamic viscoelasticity and loss of the cured product using a dynamic viscoelasticity measuring device. The loss tangent is measured, and the temperature at which the loss tangent (tanδ) shows the maximum value is preferably 100°C or higher. Preferably, the temperature is 110°C or higher, more preferably 110°C or higher, and even more preferably 120°C or higher. It is preferable that the temperature is 130°C or higher. There is no upper limit, but it is preferably 250°C or lower. By setting the content within the above range, the shape of the cured product is stable and less likely to deform even at high temperatures. This improves the reliability of the material and broadens the range of applications it can be used in. can.

[0038] <Lens> The lens is made of a cured product obtained by curing the above-mentioned curable composition. For example, electronic devices such as mobile phones, laptops, tablets, digital cameras, and automobiles The lens can be used for cameras and the like that are attached to buildings, etc. The lens can be made of the cured product of the present invention alone or The molded article may be made of a transparent substrate such as a flat glass or a glass wafer. The lens may be a hybrid lens comprising the above-mentioned cured product molded on a transparent substrate. [Example]

[0039] The present invention will be described in more detail below with reference to examples, but the present invention will not be limited to the gist of the present invention. However, the present invention is not limited to the following examples. The measurement and evaluation methods used in the present invention are as follows.

[0040] (1) Refractive index The curable composition was cured to prepare a cured product having a thickness of 1 mm. The fluorine D line (589 nm, 25°C) was measured using a multi-wavelength Abbe refractometer (manufactured by Atago Co., Ltd., "DR The measurement was carried out using methylene iodide (Corporation (manufactured by Atago) was used.

[0041] (2) Glass transition temperature The curable composition was cured to prepare a cured product having a thickness of 1 mm. The temperature at which the loss tangent (tanδ) reaches its maximum value is called the glass transition point of the cured product. The measurements were carried out using a dynamic viscoelasticity measuring device (TA Instruments Japan Co., Ltd.). The measurement conditions were tension mode and measurement frequency 10 Hz. did.

[0042] (3) Evaluation of foreign matter The curable composition was cured to prepare a cured product (lens) having a thickness of 1 mm. The side is covered with a silicone rubber sheet (Azwan Corporation silicone rubber sheet 300mm x 30 The sample was sandwiched between two pieces of glass (0 mm x 1 mm) and fixed on both sides with glass plates. The composition is glass plate / silicone rubber sheet / hardened product / silicone rubber sheet / glass plate. A heating test was carried out at 240°C for 10 minutes, and the cured product (lens) and foreign matter adhering to the glass plate were visually inspected. When no foreign matter was observed, it was rated as A (good condition), and when foreign matter was observed, it was rated as B. It was evaluated as follows.

[0043] (Production of Curable Composition) The materials shown in Table 1 were mixed in the mass ratios shown in Table 1. The materials in Table 1 are as follows: do. (Meth)acrylate having a fluorene structure: A In the above formula (1), R 1 , R 2 , R 3 , R 4 A compound where m is a hydrogen atom and m and n are 1 thing. (Meth)acrylate having a biphenyl structure: B-1 ortho-phenylphenoxyethyl acrylate (Meth)acrylate with a phenoxyphenyl structure: B-2 Meta-phenoxyphenyl methyl acrylate Trifunctional or higher multifunctional (meth)acrylates: Trimethylolpropane trimethacrylate (C-1) Dipentaerythritol hexaacrylate (C-2) 15-functional urethane acrylate (U-15HA manufactured by Shin-Nakamura Chemical Co., Ltd.) (C- 3) Benzyl methacrylate: D Polymerization initiator that is liquid at 25°C: E 2-Hydroxy-2-methyl-1-phenyl-propan-1-one Polymerization initiator that is solid at 25°C: F 1-Hydroxycyclohexyl phenyl ketone Antioxidant: G Tetrakis-[methylene-3-(3',5'-di-t-butyl-4'-hydroxyphenyl] Nyl)propionate]methane Curing agent: H Di-n-hexyl sulfide

[0044] [Table 1]

[0045] [Example 1] The curable composition shown in Table 1 was applied to a silicone rubber sheet having a thickness of 1 mm and an inner diameter of 30 mm. The mixture was poured into a mold made of glass plates, and then sealed by stacking glass plates on top. On the glass surface, the illuminance is 60mW and the cumulative light amount is 2000mJ / cm 2 UV radiation from high pressure mercury The cured product (lens) was then irradiated with ray and 30 mm in diameter and 1 mm in thickness. The cured product was peeled off from the plate and then heat treated at 160°C for 1 hour. The cured product thus obtained was measured or evaluated for the items shown in Table 2 using the methods described above. As shown in Table 2, the refractive index and glass transition point were high, and no foreign matter was generated, resulting in a favorable result.

[0046] [Examples 2 to 6] The same procedure as in Example 1 was repeated except that the composition of the curable composition was changed as shown in Table 1. The properties of the cured product are shown in Table 2 below.

[0047] [Comparative Examples 1 and 2] The same procedure as in Example 1 was repeated except that the composition of the curable composition was changed as shown in Table 1. The properties of the obtained cured product are shown in Table 2 below. This was what was occurring.

[0048] [Table 2]

Claims

1. A curable composition comprising a (meth)acrylate having a fluorene structure, a (meth)acrylate having a biphenyl or phenoxyphenyl structure, a trifunctional or higher polyfunctional (meth)acrylate, and a polymerization initiator that is liquid at 25°C, The (meth)acrylate having a fluorene structure is represented by the following formula (1): 【Chemical Formula 1】 (In formula (1), R １ , R ２ , R ３ , R ４ are each independently a hydrogen atom or a methyl group, m is an integer of 0 to 5, and n is an integer of 0 to 5. is a compound represented by the proportion of the (meth)acrylate having a fluorene structure is 15 to 95% by mass relative to the total mass of all structural units constituting the curable composition; the proportion of the (meth)acrylate having a biphenyl or phenoxyphenyl structure is 3 to 80 mass% relative to the total mass of all structural units constituting the curable composition, A curable composition, in which the proportion of trifunctional or higher polyfunctional (meth)acrylate (excluding the (meth)acrylate having a fluorene structure, biphenyl structure, or phenoxyphenyl structure) is 5 to 50 mass% or less relative to the total mass of all structural units constituting the curable composition.

2. 2. The curable composition according to claim 1, wherein the (meth)acrylate having a biphenyl or phenoxyphenyl structure is a phenylphenoxyalkyl (meth)acrylate or a phenoxyphenylalkyl (meth)acrylate.

3. 3. The curable composition according to claim 1, wherein the molecular weight of the radical generated from the polymerization initiator that is liquid at 25° C. is 95 or less.

4. The curable composition according to any one of claims 1 to 3, further comprising an antioxidant.

5. The curable composition according to any one of claims 1 to 4, wherein the proportion of the polymerization initiator that is liquid at 25°C is 0.1 to 10 mass% relative to the total mass of all structural units constituting the curable composition.

6. A cured product of the curable composition according to any one of claims 1 to 5.

7. A lens comprising the cured product according to claim 6.

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