JP2020002291A - Photosetting composition - Google Patents

Abstract

To provide a photosetting composition which is a low viscosity liquid and forms a cured article having high Abbe number, low refraction index, and high partial dispersion ratio θgF, further especially a photosetting composition which forms a cured article excellent in balance of light weight, transparency, low optical strain, transferability of a fine shape, adhesiveness with a substrate, and a releasability from a molding die, and useful for lens formation, especially hybrid lens formation by an optical imprint method.SOLUTION: There is provided a photosetting composition for lens formation, containing following components (A), (B) and (C), and having a weight ratio of the component (A) based on the component (B), (A/B) of 25/75 to 75/25, and total amount of the components (A) and (B) of 70 wt.% or more of whole photosetting composition. (A) urethane (meth)acrylate. (B) a propylene glycol mono(meth)acrylate compound represented by the following general formula 1. [Formula 1] CH=C(R)-COO-[CH(CH)CHO]-R, wherein Rrepresents a hydrogen atom or a methyl group, Rrepresents an alkyl group having 1 to 3 carbon atoms, n represents an integer of 2 to 5. (C) a photoinitiator.SELECTED DRAWING: None

Description

  The present invention relates to a photocurable composition for forming a lens, wherein the cured product obtained by photocuring has a high Abbe number.

  Conventionally, a transparent material such as glass or resin has been used as a material for forming a lens. In recent years, with the development of optical-related industries such as displays, signage, imaging sensors, optical communication, solar cells, and lighting, various types of lenses have been required, and in particular, thermoplastic resins and Various transparent resins such as light / thermosetting resins have been developed.

  Furthermore, a hybrid lens in which a resin is laminated on glass has been found in order to reduce the thickness of the entire optical system or to achieve an advanced optical function. Such a hybrid lens is formed by forming an aspherical shape or a fine shape, which is difficult to mold with glass alone, on a resin on the surface, and, in terms of manufacturing method, usually has a flat glass or a relatively simple curvature. A resin layer having an aspherical shape or a fine shape is formed on the surface of a base material by a photo-imprint method using a photo-curable composition with glass as a base material. Although a thermal imprinting method using a thermosetting composition or a thermoplastic resin is also employed, such a thermal imprinting method generally requires a long time, and thus tends to be inferior in productivity. The thickness of the laminated resin layer is usually several μm to several hundred μm.

Specifically, such a photo-imprinting method involves photo-curing a relatively low-viscosity liquid photo-curable composition in a gap between a substrate and a mold, and peeling off only the mold (demolding). This is a method for producing a laminate comprising a substrate / photocurable resin (cured product). If the surface of the mold has an aspherical shape, a Fresnel lens shape, a texture shape, a lenticular shape having periodic irregularities, a microlens shape having a curvature, or the like, it can be transferred to the surface of the cured product. Generally, it is difficult to perform aspherical surface processing or fine processing on a glass surface by mechanical methods such as cutting and polishing, and fine processing by wet / dry etching is expensive and requires a large area. And mass production is difficult. However, if the optical imprinting method is used, it is possible to manufacture a lens that has been subjected to aspherical processing and fine processing with high accuracy and high productivity. Further, by using such a photo-imprinting method, it is possible to further laminate another photo-curable resin on a laminate of glass / photo-curable resin (cured product), and a large number of lenses can be formed by such a laminate. The optical system can be reduced in thickness by consolidating into one lens.
It should be noted that the above-described mold releasability, fine transferability, adhesion between a substrate and a photocurable resin, and the like are sometimes collectively referred to as photoimprintability.

On the other hand, in the above-mentioned various transparent resins, transparency, low optical distortion, low specific gravity, as well as optical performance such as refractive index and Abbe number are important. A resin having a low refractive index or an extremely low Abbe number or a high Abbe number is required. For example, among optical elements that enable the naked eye 3D, there is an optical element in which a high-refractive-index resin lens and a low-refractive-index resin lens are laminated. A high / low refractive index resin of 0.1 or more is required, and both resins are required to have a high Abbe number (low chromatic dispersion) in order to enable the naked eye 3D in a wide wavelength range.
The Abbe number is a value representing the wavelength dependence of the refractive index. Generally, the refractive index nF at 486 nm, the refractive index nD at 589 nm, and the refractive index nC at 656 nm are as follows according to JIS Z 8120. The Abbe number νD calculated according to Equation 2 is used.
[Equation 2] Abbe number νD = (nD−1) / (nF−nC)

  Among these, there is a strong demand for a resin having an extremely high Abbe number, that is, an extremely small chromatic dispersion, and specifically, a resin having an Abbe number νD55 or more is required. Furthermore, in the hybrid lens, not only a high Abbe number but also an optical imprint material having an extremely low refractive index has been demanded for the purpose of reducing interface reflection with an air layer. Specifically, the photocurable composition forms a cured product having an Abbe number νD of 55 or more and a refractive index nD of 1.5 or less.

As a background of such demands, conventionally, resin for forming a lens has been developed mainly for a resin having a high refractive index and a high Abbe number for the purpose of shortening the focal length and reducing the chromatic dispersion as a single lens. However, on the other hand, in recent years, a resin having a low refractive index and an extremely high Abbe number has been demanded.
In general, the Abbe number νD of a transparent resin is about 30 to 60. For example, the Abbe number νD of a polycarbonate resin (PC) generally used as a transparent material is 30, and the Abbe number νD of a polyethylene terephthalate resin (PET). Is 39, the Abbe number νD of the cycloolefin polymer (COP) is 57, and the Abbe number νD of the acrylic resin (PMMA) is 58. Further, generally, the refractive index nD of the transparent resin is about 1.5 to 1.7.

  As such a resin having a high Abbe number, a fluorine-based resin is known. Some fluororesins have high transparency, but are usually coating materials for forming a thin film, and it is difficult to form a relatively thick lens. An acrylate compound or an epoxy compound having a fluorinated alkyl group can be cured by light / heat, but generally has poor curability, so that the refractive index and Abbe number of the obtained cured product are stable. In addition, the water- and oil-repellency of the hybrid lens deteriorates, and it does not adhere to substrates such as glass, and is easily repelled from the mold surface. Have difficulty.

Further, in recent years, a resin having a controlled partial dispersion ratio in addition to a high Abbe number and a low refractive index has been demanded. The partial dispersion ratio is a value representing the wavelength dependence of the refractive index in a specific wavelength range. For example, the partial dispersion ratio θgF in the blue region is a refractive index nG at 436 nm, a refractive index nF at 486 nm, and a refractive index at 656 nm. It is calculated from nC according to the following equation 3.
[Equation 3] Partial dispersion ratio θgF = (nG−nF) / (nF−nC)
Similarly, the partial dispersion ratio θcT in the red region is calculated from the refractive index nF at 486 nm, the refractive index nC at 656 nm, and the refractive index nT at 1014 nm according to the following equation 4.
[Equation 4] Partial dispersion ratio θcT = (nC−nT) / (nF−nC)
Similarly, a partial dispersion ratio in each wavelength band is defined using partial dispersion (nF-nC) as a denominator.

  Among the partial dispersion ratios, the partial dispersion ratio θgF in the blue region is important, and a lens material having a high partial dispersion ratio θgF is required to improve the definition of a display or an imaging sensor. However, it is more difficult to improve the partial dispersion ratio θgF than to improve the Abbe number. The reason for this is that a composition design that increases only the refractive index nG of blue 436 nm is required. In particular, at present, there is no known resin having a high Abbe number and a low refractive index but a high partial dispersion ratio θgF. Even glasses having a wide range of optical performances, there are few that have Abbe number νD55 or more and refractive index nD1.5 or less and partial dispersion ratio θgF of 0.5 or more. Is 0.54.

Under such circumstances, as a material for forming a lens having a high Abbe number, an optical resin material obtained by homopolymerizing a specific (meth) acrylate or copolymerizing with another monomer has been proposed (for example, , Patent Document 1.).
Further, a lens in which a photo / thermosetting composition containing a specific di (meth) acrylate is polymerized and cured has been proposed (for example, Patent Document 2).
Further, there has been proposed an optical plastic having a low refractive index and a high Abbe number obtained by polymerizing a thermosetting composition containing a specific di (meth) acrylate (for example, Patent Document 3).
Further, it is disclosed that a specific photocurable composition gives a cured product having a high Abbe number, which is capable of photoimprinting (for example, Patent Document 4).
It is also disclosed that a specific photocurable composition gives a cured product having a high Abbe number and a low refractive index (for example, Patent Documents 5 and 6).
It is also disclosed that a specific composition gives a cured product having a high Abbe number and a low refractive index (for example, Patent Document 7).
Further, it is disclosed that a specific photocurable composition containing metal oxide fine particles gives a cured product having a high Abbe number and a low refractive index, and is useful for forming a hybrid lens (for example, Patent Document 1). 8).
Further, it is disclosed that a specific photocurable composition is useful for adjusting the refractive index and useful for manufacturing a laminated optical member (for example, Patent Document 9).
Further, as a photocurable composition for photoimprint, a photocurable composition having excellent transfer accuracy has been proposed (for example, Patent Document 10).

JP-A-61-73705 JP-A-2-141702 JP-A-4-366115 JP 2010-150489 A JP 2017-141356 A JP 2017-141357 A JP-T-2003-506499 JP, 2011-23749, A JP 2009-48184 A JP 2013-36027 A

However, with the thermoplastic resin disclosed in Patent Document 1, a lens cannot be formed by an optical imprinting method. Since the monomer used as a raw material is also a monofunctional acrylate, it is difficult to obtain a cured product by photocuring. Furthermore, it has a high Abbe number but a high refractive index, which makes it difficult to respond to recent optical designs.
Further, even when the photo / thermosetting composition disclosed in Patent Document 2 is used, the maximum value of the Abbe number is 54 and the refractive index is high. Furthermore, since the specific gravity is 1.2 or more, it is difficult to reduce the weight of the lens.
Further, even if the thermosetting composition disclosed in Patent Document 3 is used, only a plastic having an Abbe number of less than 35 can be obtained, and the refractive index exceeds 1.5. Furthermore, since a monomer containing a fluorinated alkyl group is used as an essential component, photocuring is difficult, and thermal curing requires a long time (Example: 16 hours).
Further, when the photocurable composition disclosed in Patent Document 4 is used, a cured product having an Abbe number of 56 can be obtained, but a large amount of light and a long time are required for photocuring (Example is about 8 minutes at 15J). ), Poor productivity.
In addition, when the photocurable compositions disclosed in Patent Documents 5 and 6 are used, a cured product having an Abbe number of 57 can be obtained, but the refractive index is 1.5 or more. In short, it is difficult to say that the productivity is excellent (Examples 4J and 5J).
Further, when the composition disclosed in Patent Document 7 is used, although a cured product having an Abbe number of 57 and a refractive index of 1.5 or less can be obtained, it is necessary to thermally polymerize after preliminary polymerization by light, It is hard to say that it is photocurable.
In addition, the photocurable composition disclosed in Patent Document 8 has only a cured product having an Abbe number of 35 or less, and has a partial dispersion ratio θgF of 0.47 or less. In addition, a dispersion solvent is an essential component, and at the time of photocuring, the dispersion solvent must be removed and the composition must be melted by heating. Furthermore, since a fluorine-based monomer is used, it has poor compatibility with other components, tends to cause cloudiness or precipitation, and tends to be poor in photocurability. Generally, a photocurable composition is required to be cured with a light quantity of about J, but in the examples of this patent document, the curing light quantity exceeds 20 J despite a thin film having a thickness of 12.5 μm. However, the refractive index varies (irradiation sensitivity).
Further, with the photocurable composition disclosed in Patent Document 9, although a cured product having a refractive index of 1.5 or less can be obtained, a PET film is used because a fluorinated alkyl group-containing acrylate is used for lowering the refractive index. Although the adhesion with the substrate is obtained, the adhesion with the glass substrate is not obtained, and the production of the hybrid lens tends to be difficult.
Further, even with the photocurable composition disclosed in Patent Document 10, it is difficult to obtain a cured product having a high Abbe number. In addition, since the composition contains a non-polymerizable compound such as polypropylene glycol or polyethylene glycol, the non-polymerizable compound is easily precipitated or eluted from the cured product, resulting in poor durability as a lens.

  Further, as a photocurable composition for photoimprinting, a composition containing a lubricant or a release agent has been proposed, but the transfer accuracy is improved, but the durability of the lens tends to be poor.

  Under such a background, the present invention is a photocurable composition that is a low-viscosity liquid, forms a cured product having a high Abbe number, a low refractive index, and a high partial dispersion ratio θgF. It forms a cured product that is excellent in balance between lightness, transparency, low optical distortion, transferability of fine shapes, adhesion to a substrate, and releasability from a mold. It is an object of the present invention to provide a photocurable composition useful for forming a hybrid lens by a printing method.

As a result of intensive studies by the present inventors, the photocurable composition for forming a lens contains the following components (A), (B), and (C), and the component (A) with respect to the component (B). Is a weight ratio (A / B) of 25/75 to 75/25, and the total amount of the components (A) and (B) is 70% by weight or more of the entire photocurable composition. The present inventors have found that the above-mentioned object is solved, and have completed the present invention.
(A) Urethane (meth) acrylate.
(B) A propylene glycol mono (meth) acrylate compound represented by the following general formula 1.
[Equation 1]
_{CH 2 = C (R 1)} -COO- [CH (CH 3) CH 2 O] n -R 2
(Here, R ₁ represents a hydrogen atom or a methyl group, R ₂ represents an alkyl group having 1 to 3 carbon atoms, and n represents an integer of 2 to 5.)
(C) a photopolymerization initiator.

  The photocurable composition of the present invention is a low-viscosity liquid, a high Abbe number, a low refractive index, and a photocurable composition that forms a cured product having a high partial dispersion ratio θgF. It forms a cured product with excellent balance of lightness, transparency, low optical distortion, transferability of fine shape, adhesion to substrate, and releasability from mold. It is useful for producing a hybrid lens with high accuracy.

  Further, among the photocurable compositions, the cured product after photocuring has an Abbe number νD of 55 or more, a refractive index nD of 1.5 or less, and a partial dispersion ratio θgF of 0.5 or more. It becomes more useful by manufacturing a high-precision hybrid lens by the imprint method.

Hereinafter, the present invention will be described in detail, but these are merely examples of desirable embodiments.
In the present invention, (meth) acryl means acryl or methacryl, (meth) acryloyl means acryloyl or methacryloyl, and (meth) acrylate means acrylate or methacrylate.

The photocurable composition of the present invention contains the following components (A), (B), and (C).
(A) Urethane (meth) acrylate.
(B) A propylene glycol mono (meth) acrylate compound represented by the following general formula 1.
[Equation 1]
_{CH 2 = C (R 1)} -COO- [CH (CH 3) CH 2 O] n -R 2
(Here, R ₁ represents a hydrogen atom or a methyl group, R ₂ represents an alkyl group having 1 to 3 carbon atoms, and n represents an integer of 2 to 5.)
(C) a photopolymerization initiator.

  The components constituting the photocurable composition will be sequentially described below.

<Component (A)>
In the present invention, urethane (meth) acrylate used as the component (A) is excellent in quick-curing properties, and is an effective component for ensuring adhesion to a substrate. The urethane (meth) acrylate is not particularly limited, and a known compound can be used. For example, a polyalkylene glycol-based compound, a polyisocyanate-based compound, and a hydroxyl group-containing (meth) acrylate-based compound are reacted. May be used.

Examples of the polyalkylene glycol-based compound include polyethylene glycol, polypropylene glycol, polybutylene glycol, polypentylene glycol, polyneopentylene glycol, and a polymer of polymethylene glycol represented by the following general formula 5, and the like. .
[Equation 5]
HO-[(CH ₂ ) mO] -H
(Here, m represents an integer of 3 to 10.)

  Among these, a polyalkylene glycol compound other than polyethylene glycol is preferable in terms of lowering the water absorption of the cured product, and more preferably a polyalkylene compound represented by the above general formula 5 in terms of increasing the Abbe number of the cured product. A polymer of methylene glycol, more preferably, a polymer of polymethylene glycol having m of 3 to 5 in terms of adhesion between the substrate and the cured product, particularly preferably, a release property of the cured product from a mold. And a polymer of polytetramethylene glycol, particularly preferably a polymer of polytetramethylene glycol having a molecular weight of 500 to 1500 in view of the viscosity of the photocurable composition.

Specific examples of the polyisocyanate-based compound include, for example, isophorone diisocyanate, bis (isocyanatomethyl) tricyclo [5.2.1.0 ^2,6 ] decane, norbornane isocyanatomethyl, 1,3-diisocyanatocyclohexane 1,3-bis (isocyanatomethyl) cyclohexane, 1,4-diisocyanatocyclohexane, 1,4-bis (isocyanatomethyl) cyclohexane, bis (4-isocyanatocyclohexyl) methane, 2,2-bis ( 4-isocyanatocyclohexyl) propane, hydrogenated xylylene diisocyanate, hydrogenated diphenylmethane diisocyanate, and the like. Above all, isophorone diisocyanate and hydrogenated diphenylmethane diisocyanate are preferred from the viewpoint of reducing the water absorption of the cured product, and more preferably isophorone diisocyanate from the viewpoint of reducing the viscosity of the photocurable composition.

  Specific examples of the hydroxyl group-containing (meth) acrylate compound include, for example, 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 2-hydroxybutyl (meth) acrylate, and 2-hydroxy-3- (Meth) acryloyloxypropyl (meth) acrylate, pentaerythritol tri (meth) acrylate, dipentaerythritol penta (meth) acrylate, and the like. Of these, 2-hydroxyethyl (meth) acrylate and pentaerythritol tri (meth) acrylate are preferred from the viewpoint of inexpensiveness.

  The method for producing the urethane (meth) acrylate is generally such that the polyalkylene glycol-based compound, the polyisocyanate-based compound, and the hydroxyl group-containing (meth) acrylate-based compound are charged and reacted separately or collectively in a reactor. The method of reacting a hydroxyl group-containing (meth) acrylate-based compound with a reaction product obtained by previously reacting an alkylene glycol-based compound with a polyisocyanate-based compound is advantageous in terms of reaction stability and reduction of by-products. Useful.

  Examples of commercially available urethane (meth) acrylates as the component (A) include, for example, "UA-160TM" and "UA-1100H" manufactured by Shin-Nakamura Chemical Co., Ltd., and "UV-" manufactured by Nippon Synthetic Chemical Industry Co., Ltd. 6640B "and the like.

  The Abbe number νD of the urethane (meth) acrylate is preferably 40 or more, more preferably 45 or more, and further preferably 50 or more. When the Abbe number νD of the urethane (meth) acrylate is equal to or more than the lower limit, the Abbe number νD of the cured product can be improved. Generally, the upper limit of the Abbe number νD of urethane (meth) acrylate is 100.

  Further, the refractive index nD of the urethane (meth) acrylate is preferably 1.5 or less, more preferably less than 1.5, further preferably 1.49 or less, and 1.4 or more. Preferably, it is more preferably 1.45 or more. By setting the refractive index nD of the urethane (meth) acrylate to the upper limit or less, the refractive index nD of the cured product can be reduced. Generally, the lower limit of the refractive index nD of urethane (meth) acrylate is 1.3.

  Further, such a urethane (meth) acrylate preferably contains an alicyclic structure in the chemical structure from the viewpoint of reducing the water absorption of the photocurable composition and the cured product. More preferably, it has two or more alicyclic structures from the viewpoint of further reducing water absorption, and particularly preferably does not contain an aromatic ring from the viewpoint of light resistance of the cured product. In addition, urethane (meth) acrylate can be used alone or in combination of two or more.

<Component (B)>
In the present invention, the propylene glycol mono (meth) acrylate compound used as the component (B) is essential for reducing the viscosity of the photocurable composition, reducing the weight of the cured product, increasing the Abbe number, and decreasing the refractive index. It is an essential component for balancing the adhesion of the cured product to the substrate and the releasability from the mold. By using such a propylene glycol mono (meth) acrylate-based compound, it is possible to form a hybrid lens by a photo-imprinting method, which has been difficult with a fluorine-based resin or a fluorine-based monomer-containing photocurable composition.

  When a propylene glycol di (meth) acrylate compound is used instead of the propylene glycol mono (meth) acrylate compound, the effect of reducing the weight and lowering the refractive index of the cured product is not significant. The reason is that the resulting cured product forms a highly crosslinked structure, and the density of atoms or atomic groups is increased. This tendency is the same for trifunctional or higher functional (meth) acrylate compounds having a propylene glycol chain.

The propylene glycol mono (meth) acrylate compound of the above component (B) is not particularly limited as long as it is represented by the following formula 1, and a known compound can be used.
[Equation 1]
_{CH 2 = C (R 1)} -COO- [CH (CH 3) CH 2 O] n -R 2
(Here, R ₁ represents a hydrogen atom or a methyl group, R ₂ represents an alkyl group having 1 to 3 carbon atoms, and n represents an integer of 2 to 5.)

  Examples of the propylene glycol mono (meth) acrylate compound include dipropylene glycol monomethyl ether mono (meth) acrylate, dipropylene glycol monoethyl ether mono (meth) acrylate, and dipropylene glycol monopropyl ether mono (meth) acrylate. Tripropylene glycol mono (meth) acrylate compounds, tripropylene glycol monomethyl ether mono (meth) acrylate, tripropylene glycol monoethyl ether mono (meth) acrylate, and tripropylene glycol monopropyl ether mono (meth) acrylate Glycol mono (meth) acrylate compound, tetrapropylene glycol monomethyl ether mono (meth) acrylate Tetrapropylene glycol mono (meth) acrylate compounds such as tetrapropylene glycol monoethyl ether mono (meth) acrylate and tetrapropylene glycol monopropyl ether mono (meth) acrylate, pentapropylene glycol monomethyl ether mono (meth) acrylate, pentapropylene glycol Examples include pentapropylene glycol mono (meth) acrylate compounds such as monoethyl ether mono (meth) acrylate and pentapropylene glycol monopropyl ether mono (meth) acrylate.

  Among these, tripropylene glycol monomethyl ether mono (meth) acrylate, tripropylene glycol monoethyl ether mono (meth) acrylate, tripropylene glycol monopropyl ether mono (meth) acrylate, etc., from the viewpoint of reducing the Abbe number of the cured product. The tripropylene glycol mono (meth) acrylate-based compound is more preferable, and more preferably, in terms of the viscosity of the photocurable composition, tripropylene glycol monomethyl ether mono (meth) acrylate and tripropylene glycol monoethyl ether mono (meth) Acrylates are preferred. The propylene glycol mono (meth) acrylate compound can be used alone or in combination of two or more.

  Examples of commercially available propylene glycol mono (meth) acrylate compounds as the component (B) include, for example, “AM-30PG” manufactured by Shin-Nakamura Chemical Co., Ltd.

  The Abbe number νD of the propylene glycol mono (meth) acrylate compound is preferably 45 or more, more preferably 48 or more, and further preferably 50 or more. By setting the Abbe number νD of the propylene glycol mono (meth) acrylate-based compound to a lower limit or more, the Abbe number νD of the cured product can be improved.

  Further, the refractive index nD of the propylene glycol mono (meth) acrylate compound is preferably 1.5 or less, more preferably 1.4 to 1.5, further preferably 1.41 to 1.47, Particularly preferably, it is 1.42 to 1.45. By setting the refractive index nD of the propylene glycol mono (meth) acrylate-based compound to an upper limit or less, the refractive index nD of the cured product can be reduced.

  In the present invention, the reason why the propylene glycol chain having a relatively small number of repeating units forms a cured product having a high Abbe number and a low refractive index is not clear, but the atomic group volume of the propylene glycol chain is substantially the same. It is presumed that, since it is larger than the atomic group volume of an ethylene glycol chain or a trimethylene glycol chain having a molecular weight, the entire refractive index is reduced, and in particular, the refractive index (for example, nF) in the blue region is reduced (see Equation 2). . In terms of chemical structure, it is presumed that the branched methyl group in propylene glycol increases the atomic group volume and reduces the interaction between glycol chains and urethane bonds.

  The total amount of the components (A) and (B) in the photocurable composition in the present invention is at least 70% by weight, preferably at least 75% by weight, more preferably at least 80% by weight of the entire photocurable composition. % Or more. By setting the total amount of the component (A) and the component (B) to be equal to or more than the lower limit, a photocurable composition that forms a cured product having a high Abbe number and a low refractive index can be obtained, and the lightness can be reduced. A cured product having an excellent balance of transparency, low optical distortion, adhesion to a substrate, and releasability from a mold can be formed.

  The mixing ratio (A / B) of the component (A) to the component (B) in the present invention is 25/75 to 75/25, preferably 30/70 to 70/30, and more preferably 35/65 to 25, by weight. 40/60. By setting the amount of the component (A) to be not less than the lower limit, the adhesion to the substrate and the mold can be improved. Conversely, if the amount is not more than the upper limit, the releasability from the mold can be improved. Can be improved. Further, by setting the amount of the component (B) to be not less than the lower limit, the photocurable composition can be made a low-viscosity liquid and the weight of the cured product can be reduced. Conversely, by setting the content to the upper limit or less, the photocurability can be improved.

<Component (C)>
In the present invention, the photopolymerization initiator used as the component (C) may be any one capable of generating a radical by the action of light. For example, 2,4,6-trimethylbenzoyldiphenylphosphine oxide, bis ( 2,4,6-trimethylbenzoyl) -phenylphosphine oxide, 4-phenoxydichloroacetophenone, 4-t-butyl-dichloroacetophenone, diethoxyacetophenone, 2-hydroxy-2-methyl-1-phenylpropan-1-one , 1- (4-isopropylenephenyl) -2-hydroxy-2-methylpropan-1-one, 1- (4-dodecylphenyl) -2-hydroxy-2-methylpropan-1-one, 4- (2 -Hydroxyethoxy) -phenyl (2-hydroxy-2-propyl) ketone, 1- Droxycyclohexyl phenyl ketone, 2-methyl-1- [4- (methylthio) phenyl] -2-morpholinopropane-1, benzoin, benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether, benzoin isobutyl ether, benzyl dimethyl ketal, Benzophenone, benzoylbenzoic acid, methyl benzoylbenzoate, 4-phenylbenzophenone, hydroxybenzophenone, 4-benzoyl-4′-methyldiphenylsulfide, 3,3′-dimethyl-4-methoxybenzophenone, thioxanthone, 2-chlorothioxanthone , 2-methylthioxanthone, 2,4-dimethylthioxanthone, isopropylthioxanthone, camphorquinone, dibenzosuberone, 2-ethylanthraquino 4,4 ′, 4 ″ -diethylisophthalophenone, 3,3 ′, 4,4′-tetra (t-butylperoxycarbonyl) benzophenone, α-acyloxime ester, methylphenylglyoxylate, 9,10-fe Nanthrenequinone, 4- (2-hydroxyethoxy) phenyl- (2-hydroxy-2-propyl) ketone, etc. Among these, 2,4,6-trimethylbenzoyldiphenylphosphine oxide and 1-hydroxy Cyclohexyl phenyl ketone is preferred.

  The content of the component (C) is preferably 0.01 to 5% by weight, more preferably 0.1 to 4% by weight, and still more preferably 0.3 to 3% by weight of the entire photocurable composition. And particularly preferably 0.5 to 2% by weight. If the content is too small, the curing rate tends to be low, and if it is too large, the hue of the cured product tends to deteriorate.

  Further, as an auxiliary of the photopolymerization initiator, for example, triethanolamine, triisopropanolamine, 4,4′-dimethylaminobenzophenone (Michler's ketone), 4,4′-diethylaminobenzophenone, 2-dimethylaminoethylbenzoic acid, Ethyl 4-dimethylaminobenzoate, ethyl (4-butoxy) ethyl 4-dimethylaminobenzoate, isoamyl 4-dimethylaminobenzoate, 2-ethylhexyl 4-dimethylaminobenzoate, 2,4-diethylthioxanthone, 2, It is also possible to use 4-diisopropylthioxanthone or the like in combination.

  In the present invention, in addition to the urethane (meth) acrylate of the component (A) and the propylene glycol mono (meth) acrylate compound of the component (B), a monomer copolymerizable with these components may be used as an auxiliary component. Can be blended in a range that does not impair the gist of the invention. The amount of the auxiliary component is less than 30% by weight of the entire photocurable composition. Such an amount is preferably less than 25% by weight, more preferably less than 20% by weight.

Such auxiliary components include, for example,
Methyl (meth) acrylate, ethyl (meth) acrylate, lauryl (meth) acrylate, n-butyl (meth) acrylate, hexyl (meth) acrylate, heptyl (meth) acrylate, octyl (meth) acrylate, nonyl (meth) acrylate, Aliphatic mono (meth) acrylates such as decyl (meth) acrylate, isodecyl (meth) acrylate, dodecyl (meth) acrylate, n-stearyl (meth) acrylate;
Alicyclic mono (meth) acrylates such as cyclohexyl (meth) acrylate, isobornyl (meth) acrylate, tricyclodecanyl (meth) acrylate, dicyclopentenyl (meth) acrylate;
Hydroxyl groups such as 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 2-hydroxybutyl (meth) acrylate, glycerin mono (meth) acrylate, 2-hydroxyethylacrylamide, and N-methylol (meth) acrylamide Containing monofunctional (meth) acrylate;
Mono (meth) acrylates containing an ether group such as glycidyl (meth) acrylate, furfuryl (meth) acrylate, tetrahydrofurfuryl (meth) acrylate, carbitol (meth) acrylate, butoxyethyl (meth) acrylate, and acryloylmorpholine;
Phosphoric acid group-containing mono (meth) acrylates such as 2- (meth) acryloyloxyethyl acid phosphate;
Mono (meth) acrylate containing a reactive group other than (meth) acrylate group such as allyl (meth) acrylate, glycidyl (meth) acrylate,
Aliphatic di (e.g., ethylene glycol di (meth) acrylate, propylene glycol di (meth) acrylate, butylene glycol di (meth) acrylate, neopentyl glycol di (meth) acrylate, 1,6-hexanediol di (meth) acrylate, etc. (Meth) acrylate;
Hydroxyl-containing di (meth) acrylates such as glycerin di (meth) acrylate and pentaerythritol di (meth) acrylate;
Diethylene glycol di (meth) acrylate, triethylene glycol di (meth) acrylate, tetraethylene glycol di (meth) acrylate, polyethylene glycol di (meth) acrylate, dipropylene glycol di (meth) acrylate, tripropylene glycol di (meth) acrylate Ether groups such as tetrapropylene glycol di (meth) acrylate, polypropylene glycol di (meth) acrylate, ethylene glycol diglycidyl ether di (meth) acrylate, diethylene glycol diglycidyl ether di (meth) acrylate, diisocyanuric acid ethylene oxide-modified diacrylate Containing di (meth) acrylate;
Bis (hydroxy) tricyclo [5.2.1.0 ^2,6 ] decane = di (meth) acrylate, bis (hydroxymethyl) tricyclo [5.2.1.0 ^2,6 ] decane = di (meth) acrylate , Bis (hydroxy) pentacyclo [6.5.1.1 ^3,6 . 0 ^2,7 . 0 ^9,13 ] pentadecane di (meth) acrylate, bis (hydroxymethyl) pentacyclo [6.5.1.1 ^3,6 . 0 ^2,7 . 0 ^9,13 ] pentadecane di (meth) acrylate, 2,2-bis [4- (β- (meth) acryloyloxyethoxy) cyclohexyl] propane, 1,3-bis ((meth) acryloyloxymethyl) cyclohexane, 1,3-bis ((meth) acryloyloxyethyloxymethyl) cyclohexane, 1,4-bis ((meth) acryloyloxymethyl) cyclohexane, 1,4-bis ((meth) acryloyloxyethyloxymethyl) cyclohexane and the like Alicyclic di (meth) acrylate;
Aromatic di (meth) acrylates such as ethylene oxide-modified bisphenol A type di (meth) acrylate and propylene oxide-modified bisphenol A type di (meth) acrylate;
Phosphoric acid group-containing di (meth) acrylates such as 2-acryloyloxyethyl acid phosphate diester;
Trimethylolpropane tri (meth) acrylate, pentaerythritol tri (meth) acrylate, pentaerythritol tetra (meth) acrylate, dipentaerythritol penta (meth) acrylate, dipentaerythritol hexa (meth) acrylate, ditrimethylolpropane tetra (meth) acrylate Acrylate, tri (meth) acryloyloxyethoxytrimethylolpropane, glycerin polyglycidyl ether poly (meth) acrylate, isocyanuric acid ethylene oxide modified tri (meth) acrylate, ethylene oxide modified dipentaerythritol penta (meth) acrylate, ethylene oxide modified di Pentaerythritol hexa (meth) acrylate, ethylene oxide modified pentaerythritol tri (Meth) acrylate, ethylene oxide-modified pentaerythritol tetra (meth) acrylate, 1,3,5-tris ((meth) acryloyloxymethyl) cyclohexane, 1,3,5-tris ((meth) acryloyloxyethyloxymethyl) cyclohexane Trifunctional or more (meth) acrylates such as;
Pentaerythritol tetrakis (β-thiopropionate), pentaerythritol tetrakis (thioglycolate), trimethylolpropane tris (β-thiopropionate), trimethylolpropane tris (thioglycolate), diethylene glycol bis (β-thio Propionate), diethylene glycol bis (thioglycolate), triethylene glycol bis (β-thiopropionate), triethylene glycol bis (thioglycolate), dipentaerythritol hexakis (β-thiopropionate), Dipentaerythritol hexakis (thioglycolate), tris [2- (β-thiopropionyloxy) ethyl] triisocyanurate, tris (2-thioglyconyloxyethyl) triisocyanurate, tris 2- (β-thiopropionyloxyethoxy) ethyl] triisocyanurate, tris (2-thioglyconyloxyethoxyethyl) triisocyanurate, tris [3- (β-thiopropionyloxy) propyl] triisocyanurate, tris ( Polythiol such as (3-thioglyconyloxypropyl) triisocyanurate.
These auxiliary components can be used alone or in combination of two or more.

Among these, from the viewpoints of adhesion to a substrate and releasability from a mold, ether-containing mono (meth) acrylates such as tetrahydrofurfuryl (meth) acrylate and acryloylmorpholine, and bis (hydroxymethyl) tricyclo [ 5.2.1.0 ^2,6 ] decane = di (meth) acrylate, etc., alicyclic di (meth) acrylate, aromatic di (meth) acrylate such as ethylene oxide-modified bisphenol A type di (meth) acrylate, And a mixture thereof, and more preferably, tetrahydrofurfuryl (meth) acrylate, bis (hydroxymethyl) tricyclo [5.2.1.0 ^2,6 ] decane from the viewpoint of improving the partial dispersion ratio θgF of the cured product. = Di (meth) acrylate, ethylene oxide-modified bisphenol A type di (meth) acrylate, and Mixtures thereof.

  The Abbe number νD of the auxiliary component is preferably 30 or more, more preferably 35 or more, and further preferably 40 or more. When the Abbe number νD of the auxiliary component is equal to or more than the lower limit, the Abbe number νD of the cured product can be improved. The auxiliary component has a refractive index nD of preferably 1.6 or less, more preferably 1.55 or less, and still more preferably 1.5 or less. By setting the refractive index nD of the auxiliary component to the upper limit or less, the refractive index nD of the cured product can be reduced.

  The photocurable composition of the present invention may contain a solvent as necessary, but it is preferable to minimize the amount of the solvent as much as possible, and it is particularly preferable to use a solventless type. As a solventless type, not only do not use any solvent in the process of preparing the photocurable composition, but also use the solvent at the time of preparation and remove the solvent before applying the photocurable composition etc. However, it is preferable not to use any solvent. By using a solventless type, solvent drying is not required at the time of lens formation, and the lens manufacturing process can be simplified and the environmental load can be reduced.

  Various additives may be added to the photocurable composition of the present invention as long as the effects of the present invention are not impaired. Examples of additives include surfactants, silane coupling agents, chain transfer agents, antioxidants, polymerization inhibitors, yellowing inhibitors, ultraviolet absorbers, infrared absorbers, fillers, bluing agents, dyes, pigments , Oils, plasticizers, waxes, desiccants, dispersants, wetting agents, emulsifiers, gelling agents, stabilizers, defoamers, leveling agents, release agents, thixotropic agents, flame retardants, fillers, reinforcement Agents, matting agents, crosslinking agents and the like. These can be used alone or in combination of two or more.

Thus, the photocurable composition of the present invention is obtained.
Hereinafter, various characteristics of the photocurable composition of the present invention will be described.

  The photocurable composition of the present invention preferably has an Abbe number νD of 45 or more, more preferably 45 to 60, and even more preferably 47 to 55. By setting the refractive index νD of the photocurable composition to a lower limit or more, the Abbe number νD of the cured product can be improved. In general, it is often thought that when the Abbe number νD of the photocurable composition is increased, the Abbe number νD of the cured product is simply increased. However, in the photocurable composition of the present invention, the photocurable composition is The Abbe number νD of the curable composition and the Abbe number νD of the cured product are not necessarily in a proportional relationship.

  The photocurable composition of the present invention preferably has a refractive index nD of 1.49 or less, more preferably 1.4 to 1.49, still more preferably 1.43 to 1.48, and particularly preferably 1 to 1.49. .45 to 1.47. By setting the refractive index nD of the photocurable composition to the upper limit or less, the refractive index nD of the cured product can be reduced.

  In general, the Abbe number and the refractive index of the cured product can be predicted and designed to some extent from the chemical structure and the mixing ratio of the components constituting the photocurable composition. However, intermolecular interactions and molecular association states in the composition state (mixture) also affect the Abbe number and the refractive index of the cured product. It is important to control the Abbe number and the refractive index. In the present invention, not only the Abbe number and the refractive index of each component are set in a specific range, but also the Abbe number and the refractive index of the entire photocurable composition are set in a specific range.

  The photocurable composition of the present invention preferably has a viscosity at 25 ° C of 10 to 4000 mPa · s. It is more preferably 30 to 3500 mPa · s, and still more preferably 50 to 3000 mPa · s. By setting the viscosity to be equal to or higher than the lower limit, rapid curability tends to be improved. Conversely, by setting the viscosity to be equal to or lower than the upper limit, transferability of fine shapes can be improved.

  The photocurable composition of the present invention preferably has a contact angle with glass of 60 ° or less. More preferably, it is 10 to 60 °, still more preferably 20 to 50 °. By setting the contact angle to be equal to or less than the upper limit, the adhesiveness to glass can be improved. Conversely, if the contact angle is too small, the releasability from the mold tends to decrease. The contact angle can be controlled by adjusting at least one of the types and amounts of the components of the photocurable composition and the addition of a surfactant.

  Next, a method of manufacturing a laminate having fine irregularities formed on the surface by photoimprinting using the photocurable composition will be described.

For example, when a glass is used as a base material, such a laminate is manufactured by the following steps (1) to (4) and, if necessary, a step (5).
Step (1) A step of applying the photocurable composition to a mold having fine irregularities formed on the surface.
Step (2) a step of covering the photocurable composition with a glass plate.
Step (3) A step of obtaining a laminate composed of a glass plate / cured product by photocuring the photocurable composition by light irradiation.
Step (4): a step of peeling off the laminate composed of the glass plate / cured product from the mold.
Step (5) a step of heat-treating the laminate.

  In the step (1), a coating method is not particularly limited, and a known method such as a die coater, a roll coater, screen printing, and dispensing can be used. A mold, a glass mold, a resin mold, or the like can be used as a molding die. After application, leveling or defoaming may be performed. The coating thickness is generally from 0.01 to 1 mm. In addition, since the photocurable composition of the present invention has a low viscosity, it is not necessary to add a solvent. However, at the time of coating, a small amount of a solvent can be added for the purpose of improving the leveling property. In such a case, the solvent is dried immediately after the application.

  In the step (2), the surface of the glass is preferably treated with a silane coupling agent to improve the adhesion between the glass and the cured product. Further, in order to avoid entrapment of air bubbles, the photocurable composition may be applied to a part or the whole of the glass side.

In the step (3), the light irradiation is preferably performed using ultraviolet light having a wavelength of 200 to 400 nm with an irradiation light amount of 0.1 to 3 J / cm ² . A more preferable range of the irradiation light amount is 0.5 to 2.5 J / cm ² , and further preferably, 1 to ² J / cm ² . If the amount of irradiation is too small, curing tends to be insufficient, and if too large, productivity tends to decrease. Light irradiation may be performed a plurality of times. Examples of the ultraviolet light source include a metal halide lamp, a high-pressure mercury lamp, an electrodeless mercury lamp, and an LED lamp.

  In the step (4), at the time of peeling from the mold, at least one of heating and cooling of the mold and the laminate may be performed. By such a method, smooth demolding becomes possible.

  Step (5) is performed as necessary for the purpose of completing polymerization of the cured product, releasing stress strain, stabilizing hue, and the like. When such heat treatment is performed, it is usually performed at 50 to 200 ° C. for 1 to 60 minutes. Further, the heat treatment may be performed by infrared irradiation.

  As described above, the method of manufacturing a laminated body has been described using a case where glass is used as a base material, but the same applies to a case where the base material is a ceramic or resin film other than glass.

Thus, a laminate composed of the glass / cured product is obtained.
The total thickness of the laminate is preferably 0.1 to 30 mm. More preferably, it is 0.5 to 10 mm, further preferably 1 to 5 mm. If the total thickness is too small, the rigidity of the hybrid lens tends to be insufficient, and if it is too large, it tends to be difficult to reduce the weight and thickness of the hybrid lens.

  The thickness of the cured product layer need not be uniform, but is preferably 0.01 to 1 mm. More preferably, it is 0.05 to 0.7 mm, and still more preferably 0.08 to 0.5 mm. If the cured product layer is too thin, the transferability of the fine shape tends to decrease, while if too thick, the productivity tends to decrease.

  Such a laminate is suitable as a hybrid lens for an optical component.

  Hereinafter, the characteristics of the cured product obtained by curing the photocurable composition of the present invention will be described. The cured product used in the characteristics of the cured product referred to here is not a molded product or a three-dimensional molded product whose surface is formed into a fine shape, but a plate-shaped product that is molded to evaluate various characteristics. It means a molded body, and a thickness of 1 mm is a standard thickness.

  The Abbe number νD of the cured product is preferably 55 or more. It is more preferably 56 or more, and further preferably 58 or more. When the Abbe number νD is equal to or more than the lower limit, the chromatic dispersion of the lens can be reduced. The upper limit of the Abbe number of the cured product is usually 100.

  The refractive index nD of the cured product is preferably 1.5 or less. More preferably, it is 1.45 to 1.49, and still more preferably 1.46 to 1.48. When the refractive index nD is equal to or less than the upper limit, the reflection at the interface with the air layer can be reduced. Conversely, if the refractive index nD is too small, the interface reflection with the substrate tends to increase.

The partial dispersion ratio θgF of the cured product is preferably 0.5 or more. It is more preferably 0.51 to 0.8, and further preferably 0.52 to 0.7. By setting the partial dispersion ratio θgF to be equal to or more than the lower limit, the definition of the display or the imaging sensor can be improved. In order to improve the partial dispersion ratio θgF, as described above, the auxiliary components tetrahydrofurfuryl (meth) acrylate and bis (hydroxymethyl) tricyclo [5.2.1.0 ^{2, 6} ] Decane = di (meth) acrylate, ethylene oxide-modified bisphenol A type di (meth) acrylate, and a method of blending these mixtures.

  The total light transmittance of the cured product is preferably 90% or more. It is more preferably at least 91%, further preferably at least 92%. By setting the total light transmittance to the lower limit or more, the total light transmittance of the lens can be improved. The upper limit of the total light transmittance of the cured product is usually 99%.

  The haze of the cured product is preferably 1% or less. It is more preferably at most 0.5%, particularly preferably at most 0.3%. If the haze is too large, the definition of the display tends to decrease, and the sensitivity of the imaging sensor tends to decrease. The lower limit of the haze is usually 0.001%.

  The hue b * of the cured product is preferably -1 to +1. It is more preferably -0.5 to +0.5, and still more preferably -0.3 to +0.3. By setting the hue b * within ± 1, the yellow tint of the lens can be reduced and the appearance can be improved.

  The specific gravity of the cured product at room temperature (25 ° C.) is preferably 1.11 or less. More preferably, it is 1-1.11, and still more preferably, it is 1.05-1.1. When the specific gravity is equal to or less than the upper limit, the weight of the lens can be reduced. Conversely, if the specific gravity is excessively small, the lens is likely to float in water, and it tends to be difficult to wash with water. The lower limit of the specific gravity of the cured product is usually 0.9.

  The retardation of the cured product at room temperature is preferably 10 nm or less. It is more preferably at most 5 nm, further preferably at most 2 nm, particularly preferably at most 1 nm. By setting the retardation at or below the upper limit, optical distortion of the lens can be reduced. The lower limit of the retardation is usually 0.001 nm.

  The water absorption of the cured product at room temperature is preferably 2% by weight or less. More preferably, it is 0.1 to 2% by weight, and still more preferably 0.2 to 1% by weight. By setting the water absorption to the upper limit or less, the water absorption of the lens can be reduced. Conversely, if the water absorption is excessively small, it tends to be difficult to further laminate the resin on the cured product. The lower limit of the water absorption is usually 0.001% by weight.

The preferred range of the flexural modulus of the cured product differs between when used as a single lens and when used as a hybrid lens. In the case of the former, a high elastic modulus is preferable, but in the case of the latter, in order to reduce the stress on the substrate and improve the shape stability of the entire laminate, or when used as an intermediate layer having a three-layer structure Has a low elastic modulus in order to play a cushion-like role.
In the former case, the flexural modulus at room temperature is preferably 2 GPa or more, more preferably 2.5 GPa or more, and still more preferably 3 GPa or more, from the viewpoint of improving the rigidity of the lens.
In the latter case, the pressure is preferably 2 GPa or less from the viewpoint of avoiding deformation of the laminate. More preferably, it is 0.001-2 GPa, Still more preferably, it is 0.01-1 GPa. Naturally, if the flexural modulus is too small, it tends to be difficult to maintain the lens shape.

  The characteristics of the cured product can be adjusted by selecting the components constituting the photocurable composition and appropriately selecting the mixing ratio.

Hereinafter, the present invention will be described more specifically with reference to examples. However, the present invention is not limited to the following examples unless it exceeds the gist.
In the examples, “parts” and “%” mean on a weight basis unless otherwise specified.

  Each property of the photocurable composition prepared in the examples and the prepared cured product was measured according to the following measurement conditions.

(1) Viscosity of photocurable composition (mPa · s)
The photocurable composition was measured using an E-type viscometer “RE-115L” manufactured by Toki Sangyo Co., Ltd. at 25 ° C. and a rotation speed of 5 rpm (cone rotor 3 ° × R9.7). In addition, since the photocurable composition of Comparative Example 1 had a high viscosity, it was measured at a rotation number of 0.1 rpm.

(2) Photocurable composition of photocurable composition The photocurable composition is applied on a molding die (a nickel stamper having a fine surface unevenness) having a 1 mm-thick spacer provided on a peripheral portion thereof. After covering the surface of the white plate glass with a surface treatment from above, and irradiating ultraviolet light of ² J / cm ² (illuminance 250 mw / cm ² for 8 seconds) from the white plate glass surface side using a high pressure mercury lamp, the mold is peeled off. The degree of cure of the photocurable composition was observed and evaluated according to the following criteria.
That becomes insufficient curing remains × · · · gel or liquid that has been cured by raising the ○ · · · those that have been cured at a light volume 2J / cm ² △ ··· amount to 20 J / cm ²

(3) Abbe number νD
(3-1) Abbe number νD of photocurable composition
Using Atago's "Multi-Wavelength Abbe Refractometer DR-M4", the refractive index was measured at 25 ° C. at a NaD line having a wavelength of 589 nm, a NaF line having a wavelength of 486 nm, and a NaC line having a wavelength of 656 nm. The Abbe number νD was calculated from the refractive index according to the following equation 2.
[Equation 2] Abbe number νD = (nD−1) / (nF−nC)
(3-2) Abbe number νD of cured product
A cured product test piece having a length of 40 mm, a width of 8 mm, and a thickness of 1 mm was prepared, and using a “multi-wavelength Abbe refractometer DR-M4” manufactured by Atago at 25 ° C., a NaD line having a wavelength of 589 nm and a NaF having a wavelength of 486 nm. The refractive index in the line and the NaC line having a wavelength of 656 nm was measured, and the Abbe number νD was calculated from the three refractive indices according to the above equation (2).

(4) Refractive index nD
(4-1) Refractive index nD of photocurable composition
The refractive index nD was measured at 25 ° C. using a “multi-wavelength Abbe refractometer DR-M4” manufactured by Atago at a NaD line having a wavelength of 589 nm.
(4-2) Refractive index nD of cured product
A cured product test piece having a length of 40 mm, a width of 8 mm, and a thickness of 1 mm was prepared, and the refractive index nD at 25 ° C. and a NaD line of a wavelength of 589 nm was measured at 25 ° C. using “Multi-wavelength Abbe refractometer DR-M4” manufactured by Atago. It was measured.

(5) Specific gravity of cured product A cured product test piece having a length of 50 mm x a width of 50 mm x a thickness of 1 mm was prepared and measured at 23C with an electronic hydrometer "MD-300S" manufactured by Alpha Mirage.

(6) Partial dispersion ratio θgF of the cured product
A cured product test piece having a length of 40 mm, a width of 8 mm, and a thickness of 1 mm was prepared, and a refractive index nG at 436 nm and a refractive index at 486 nm at 25 ° C. by using Atago's “Multi-wavelength Abbe refractometer DR-M4”. The refractive index nC at nF and 656 nm was measured, and the partial dispersion ratio θgF was calculated from the three refractive indices according to the following equation 3.
[Equation 3] Partial dispersion ratio θgF = (nG−nF) / (nF−nC)

(7) Total light transmittance of cured product (%)
Three cured product test pieces having a length of 50 mm x a width of 50 mm x a thickness of 1 mm were prepared, and the total light transmittance (%) was measured with a haze meter "NDH-2000" manufactured by Nippon Denshoku Industries Co., Ltd. Was taken as the total light transmittance of the cured product.

(8) Haze of cured product (%)
Three cured product test pieces of 50 mm × 50 mm × 1 mm thickness were prepared, and the haze was measured using a haze meter “NDH-4000” manufactured by Nippon Denshoku Industries Co., Ltd. in accordance with JIS K7361. Is the haze of the cured product.

(9) Hue b * of cured product
Three cured product test pieces of 50 mm × 50 mm × 1 mm thickness were prepared, and the hue b * was measured using a color computer manufactured by Suga Test Instruments Co., Ltd., and the average value of the three was determined as the hue b * of the cured product.

(10) Retardation of cured product (nm)
A cured product test piece having a length of 100 mm × a width of 100 mm × a thickness of 1 mm was prepared, and the retardation at 9 places in the plane was measured at 25 ° C with a birefringence measuring device manufactured by Oak Co., Ltd., and the average value of the 9 places was measured. It was the retardation of the cured product.

(11) Peelability of laminate In the above evaluation of “(2) Photocurability of photocurable composition”, the peelability when peeling the laminate of glass / cured product from the mold is based on the following criteria. evaluated.
○ ・ ・ ・ Released without cohesive failure on the surface of cured product × ・ ・ ・ Unable to peel off from mold, or cohesive failure on surface of cured product

(12) Transferability of laminate The laminate of glass / cured product peeled from the mold in the above evaluation of “(11) Peelability of laminate” was heat-treated at 100 ° C. for 1 hour, and then the laminate was obtained. The surface of the cured product was observed under a microscope and evaluated according to the following criteria.
〇 ・ ・ ・ Transfer without breaking the fine irregularities of the mold. × ・ ・ ・ Transfer with the minute irregularities of the mold collapsed or distorted.

(13) Adhesiveness of Laminated Body According to JIS K 5400 (1990 version), the adhesiveness of the cured product to glass was evaluated by a crosshatch method in the laminated body of glass / cured product.
○ ・ ・ ・ No peeling of cured product × ・ ・ ・ Peeling of cured product

<Example 1>
(Preparation of base material and mold)
A white sheet glass having a length of 100 mm, a width of 100 mm and a thickness of 1 mm was prepared as a substrate, and the surface of the white sheet glass in contact with the photocurable composition was treated with a silane coupling agent solution. The silane coupling agent solution used has a composition of 3-methacryloxypropyltrimethoxysilane (0.1%) / isopropyl alcohol (99.9%).
A nickel stamper (surface chrome plating) having a length of 100 mm × a width of 100 mm × a thickness of 1 mm was prepared as a molding die. On the surface of the stamper, saw-like grooves having a width of 100 μm and a depth of 100 μm are formed periodically at a pitch of 100 μm as fine surface irregularities.
In addition, two pieces of glass having a length of 100 mm, a width of 100 mm, and a thickness of 1 mm were prepared in order to prepare a cured product test piece for evaluating various properties. Surface treatment was carried out with a silane coupling agent solution ("Optool", manufactured by Daikin Co., Ltd.) to obtain glass for preparing test pieces.

[Preparation of each component]
Further, the following components were prepared for Examples and Comparative Examples.
-As component (A),
(A-1): Urethane acrylate having Abbe number νD 53 and refractive index nD 1.48 (“UA-160TM” manufactured by Shin-Nakamura Chemical Co., Ltd.)
(A-2): Urethane acrylate having Abbe number νD 42 and refractive index nD 1.49 (“UA-1100H” manufactured by Shin-Nakamura Chemical Co., Ltd.)
-As component (B)
(B-1): Tripropylene glycol monomethyl ether monoacrylate having Abbe number νD 52 and refractive index nD 1.44 (“AM-30PG” manufactured by Shin-Nakamura Chemical Co., Ltd.)
(B′-1): Diethylene glycol monomethyl ether monomethacrylate having Abbe number νD 48 and refractive index nD 1.44 (“M-20G” manufactured by Shin-Nakamura Chemical Co., Ltd.)
(B′-2): 2,2,2-trifluoroethyl methacrylate having Abbe number νD 46 and refractive index nD 1.36 (“Fluorester” manufactured by Tosoh F-Tech Co., Ltd.)
-As component (C)
(C-1): 1-hydroxycyclohexyl phenyl ketone (“IRGACURE 184” manufactured by BASF)
・ As an auxiliary component,
(D-1): Tetrafurfuryl acrylate having Abbe number νD 47 and refractive index nD 1.46 (“Biscoat # 150” manufactured by Osaka Organic Chemical Industry Co., Ltd.)
(D-2): Bis (hydroxymethyl) tricyclo [5.2.1.0 ^2,6 ] decane diacrylate having an Abbe number νD 47 and a refractive index nD 1.50 (manufactured by Shin-Nakamura Chemical Co., Ltd., “A -DCP ")
(D-3): ethylene oxide-modified bisphenol A-type di (meth) acrylate having Abbe number νD 35 and refractive index nD 1.57 (“ABE-300”, manufactured by Shin-Nakamura Chemical Co., Ltd.)

[Preparation of photocurable composition I]
As the component (A), 60 parts of the component (A-1), as the component (B), 40 parts of the component (B-1), and as the component (C), 2 parts of the component (C-1) at room temperature. For 1 hour to obtain a photocurable composition I. The viscosity of the photocurable composition I was 2900 mPa · s, the Abbe number νD was 51, and the refractive index nD was 1.46.

[Preparation of cured product test piece I]
The obtained photocurable composition I was applied to the above-mentioned glass for preparing a test piece having a 1 mm-thick spacer provided on the periphery, and another glass for preparing a test piece was covered from above, and a high-pressure mercury lamp was applied. Was irradiated with ultraviolet rays of ² J / cm ² to perform photocuring. Next, the glass on both sides was peeled off, and the obtained cured product was heat-treated at 100 ° C. for 1 hour to obtain a cured product test piece I (thickness: 1 mm) for evaluating various characteristics.

[Production of laminate I]
The obtained photocurable composition I is applied on the above-mentioned mold in which a 1 mm-thick spacer is provided on the periphery, covered with a white sheet glass whose surface has been treated from above, and the white sheet glass surface is coated with a high-pressure mercury lamp. Photocuring was performed by irradiating ² J / cm ² ultraviolet rays from the side. The photocurability was good.
Next, the mold was released from the surface of the cured product on which the uneven shape was formed. The peelability was good. The obtained glass / cured product laminate was heat-treated at 100 ° C. for 1 hour to obtain a laminate I. The transfer accuracy on the surface of the cured product was good.

[Evaluation of cured product test piece I and laminate I]
The cured product test piece I had an Abbe number νD of 60, a refractive index nD of 1.48, a high Abbe number and a low refractive index. As shown in Table 2, specific gravity, partial dispersion ratio θgF, total light transmittance, haze, hue b *, and retardation had good characteristics.
Moreover, in the obtained laminated body I, the releasability was good and the transferability was good as described above. Further, the adhesion of the glass / cured product of the laminate I was good.

<Example 2>
(Preparation of photocurable composition II, etc.)
Photocurable composition II, cured product in the same manner as in Example 1, except that 40 parts of component (A-1) was used as component (A) and 60 parts of component (B-1) was used as component (B). Test piece II and laminate II were obtained.
Various properties of the obtained photocurable composition II, cured product test piece II, and laminate II were evaluated and are shown in Tables 1 and 2.

<Example 3>
(Preparation of photocurable composition III, etc.)
Photocurable composition III, cured product in the same manner as in Example 1 except that 30 parts of component (A-2) was used as component (A) and 70 parts of component (B-1) was used as component (B). Test piece III and laminate III were obtained.
Various properties of the obtained photocurable composition III, cured product test piece III, and laminate III were evaluated and are shown in Tables 1 and 2.

<Example 4>
(Preparation of photocurable composition IV, etc.)
Example 1 was repeated except that 20 parts of the component (A-1) was used as the component (A), 60 parts of the component (B-1) was used as the component (B), and 20 parts of the component (D-1) was used as an auxiliary component. Similarly, a photocurable composition IV, a cured product test piece IV, and a laminate IV were obtained.
Various properties of the obtained photocurable composition IV, cured product test piece IV, and laminate IV were evaluated and are shown in Tables 1 and 2.

<Example 5>
[Preparation of Photocurable Composition V, etc.]
Example 1 was repeated except that 37 parts of the component (A-1) was used as the component (A), 45 parts of the component (B-1) was used as the component (B), and 18 parts of the component (D-2) was used as an auxiliary component. Similarly, a photocurable composition V, a cured product test piece V, and a laminate V were obtained.
Various properties of the obtained photocurable composition V, cured product test piece V, and laminate V were evaluated and are shown in Tables 1 and 2.

<Example 6>
(Preparation of photocurable composition VI, etc.)
35 parts of the component (A-1) as the component (A), 43 parts of the component (B-1) as the component (B), and 17 parts of the component (D-2) and 5 parts of the component (D-3) as auxiliary components A photocurable composition VI, a cured product test piece VI, and a laminate VI were obtained in the same manner as in Example 1 except for using parts.
Various properties of the obtained photocurable composition VI, cured product test piece VI, and laminate VI were evaluated, and the results are shown in Tables 1 and 2.

<Comparative Example 1>
(Preparation of photocurable composition VII etc.)
Photocurable composition VII was obtained in the same manner as in Example 1, except that 80 parts of component (A-1) was used as component (A) and 20 parts of component (B-1) was used as component (B). . Further, in the same manner as in Example 1, photo-curing was performed by irradiating ² J / cm ² ultraviolet rays using a high-pressure mercury lamp.
Then, a cured product test piece VII was obtained in the same manner as in Example 1.
On the other hand, an attempt was made to release the mold from the surface of the cured product on which the fine irregularities were formed. However, peeling was impossible because of strong adhesion, and the desired glass / cured product laminate VII was obtained. Did not.
Various properties of the obtained photocurable composition VII and cured product test piece VII were evaluated and are shown in Tables 1 and 2. In addition, although the intended laminated body VII was not obtained as described above, the evaluation is shown in Table 2 with respect to the releasability and the adhesion to the glass that can be evaluated.

<Comparative Example 2>
(Preparation of photocurable composition VIII etc.)
Photocurable composition VIII, cured product in the same manner as in Example 1 except that 20 parts of component (A-1) was used as component (A) and 80 parts of component (B-1) was used as component (B). Test piece VIII and laminate VIII were obtained.
Various properties of the obtained photocurable composition VIII, cured product test piece VIII, and laminate VIII were evaluated, and are shown in Tables 1 and 2.

<Comparative Example 3>
(Preparation of photocurable composition IX etc.)
As the component (A), 42 parts of the component (A-1) and 40 parts of the component (B-1) are replaced with 40 parts of the component (B'-1), and 18 parts of the component (D-2) is used as an auxiliary component. Except for the above, a photocurable composition IX, a cured product test piece IX, and a laminate IX were obtained in the same manner as in Example 1.
Various properties of the obtained photocurable composition IX, cured product test piece IX, and laminate IX were evaluated, and the results are shown in Tables 1 and 2.

<Comparative Example 4>
[Preparation of Photocurable Composition X, etc.]
As the component (A), a photocurable composition was prepared in the same manner as in Example 1, except that 70 parts of the component (A-1) and 30 parts of the component (B′-2) were used instead of 40 parts of the component (B-1). X was obtained. Further, in the same manner as in Example 1, photo-curing was performed by irradiating ultraviolet rays of ² J / cm ² using a high-pressure mercury lamp. It was still.

<Comparative Example 4 ′>
[Preparation of Photocurable Composition X ′, etc.]
Therefore, as shown in Table 1, a photocurable composition X ′ in which the amount of the component (C-1) was increased to 4 parts was prepared, and ultraviolet rays of ² J / cm ² were obtained using a high-pressure mercury lamp in the same manner as in Example 1. Was irradiated to perform photocuring. However, the gel was insufficiently cured. Then, the photocurable composition X ′ was irradiated with ultraviolet rays at 20 J / cm ² to obtain a cured product test piece X ′ and a laminate X ′.
The cured product test piece X ′ had a yellow and whitish appearance. In the laminate X ′, the cured product was partially peeled from the glass.
Various properties of the obtained photocurable composition X ′, cured product test piece X ′, and laminate X ′ were evaluated and are shown in Tables 1 and 2. In addition, since the refractive index nG at 436 nm of the cured product test piece X ′ could not be measured, the partial dispersion ratio θgF could not be calculated.

In Comparative Example 4 ', when the blending ratio of the component (B'-2) was further increased (for example, 50 parts), curing was insufficient even when irradiated with ultraviolet rays of 20 J / cm ² . From the above results, as described above, it was confirmed that the acrylate compound having a fluorinated alkyl group was inferior in photo-imprintability.

  About the photocurable composition obtained from the said Example and the comparative example, the component and the content of each component are shown in Table 1 with the viscosity of each component, photocurability, Abbe number, and a refractive index.

Table 2 shows the specific gravity, Abbe number, refractive index, partial dispersion ratio, total light transmittance, haze, hue, and retardation of the cured product test pieces obtained from the above Examples and Comparative Examples. In addition, Table 2 shows the releasability, transferability, and adhesion to glass of the laminates obtained from the above Examples and Comparative Examples from the mold.

The photocurable compositions of Examples 1 to 6 had a lower viscosity than the photocurable composition of Comparative Example 1, formed a cured product having an excellent partial dispersion ratio θgF, and exhibited photoimprintability (peelability). (Transferability, transferability, adhesion to glass). In addition, as compared with the photocurable composition of Comparative Example 2, a cured product having an excellent partial dispersion ratio θgF was formed, and the adhesiveness to glass was excellent. Further, it can be seen that a cured product having a lower specific gravity and an excellent partial dispersion ratio θgF is formed as compared with the photocurable composition of Comparative Example 3. Further, as compared with the photocurable compositions of Comparative Examples 4 and 4 ′, they have excellent photocurability and photoimprintability, and have low specific gravity, high Abbe number, high total light transmittance, low haze, hue, and retardation. It can be seen that an excellent cured product is formed.
Further, when comparing the cured products of Examples 1 to 6, it can be seen that Examples 5 and 6 using a specific auxiliary component have a high partial dispersion ratio θgF.

  The photocurable composition for forming a lens of the present invention is a low-viscosity liquid, and the resulting cured product has excellent optical performance such as a high Abbe number, a low refractive index, and a high partial dispersion ratio θgF. It is useful as various film-forming materials such as a lens-forming material, an optical imprint material, a coating agent, an adhesive, a sealant, an adhesive, a paint, an ink, and a coating binder. In particular, it is suitably used as a lens-forming agent for forming microlenses such as lenticular lenses, Fresnel lenses, and microlens arrays on a substrate. In addition, a substrate / cured product laminate produced using the photocurable composition may be used as a light guide plate for display, an optical sheet / film, an imaging sensor, a signage, a vehicle, an optical communication, It is useful as an optical component for batteries, lighting, memories and the like.

Claims (2)

A photocurable composition for forming a lens, comprising the following components (A), (B), and (C), wherein the weight ratio (A / B) of the component (A) to the component (B) is: 25/75 to 75/25, wherein the total amount of the components (A) and (B) is at least 70% by weight of the entire photocurable composition.
(A) Urethane (meth) acrylate.
(B) A propylene glycol mono (meth) acrylate compound represented by the following general formula 1.
[Equation 1]
_{CH 2 = C (R 1)} -COO- [CH (CH 3) CH 2 O] n -R 2
(Here, R ₁ represents a hydrogen atom or a methyl group, R ₂ represents an alkyl group having 1 to 3 carbon atoms, and n represents an integer of 2 to 5.)
(C) a photopolymerization initiator.   The photocurable composition according to claim 1, wherein the cured product after photocuring has an Abbe number νD of 55 or more, a refractive index nD of 1.5 or less, and a partial dispersion ratio θgF of 0.5 or more. object.