JP7072452B2 - Photocurable composition - Google Patents

Description

The present invention relates to a photocurable composition for forming a lens, and 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 lenses are required, and thermoplastic resins and thermoplastic resins are used for the purpose of weight reduction and improvement of moldability. Various transparent resins such as light / thermosetting resins have been developed.

Furthermore, in order to make the entire optical system thinner and to achieve advanced optical functions, hybrid lenses in which resin is laminated on glass are also found. Such a hybrid lens has an aspherical shape or a fine shape formed on a resin on the surface, which is difficult to form with glass alone, and is usually made of flat glass or has a relatively simple curvature in terms of manufacturing. A resin layer having an aspherical shape or a fine shape is formed on the surface of the base material by an optical imprint method using glass as a base material and a photocurable composition. A thermal imprint method using a thermosetting composition or a thermoplastic resin is also adopted, but such a thermal imprint method generally takes a long time and tends to be inferior in productivity. Normally, the thickness of the laminated resin layer is several μm to several hundred μm.

Specifically, such a photoimprint method is a method of photocuring a relatively low-viscosity liquid photocurable composition in a gap between a base material and a molding die, and peeling (demolding) only the molding die. , A manufacturing method for obtaining a laminate made of a base material / photocurable resin (cured product). If the surface of the molding die is provided with 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, the shape can be transferred to the surface of the cured product. In general, it is difficult to perform aspherical surface processing or microfabrication by mechanical methods such as cutting and polishing on the glass surface, and the method of microfabrication by wet / dry etching is expensive and increases the area. And mass production is difficult. However, if the optical imprint method is used, it is possible to manufacture a lens that has been subjected to aspherical surface processing or microfabrication with high accuracy and high productivity. Further, by using such an optical imprint method, it is possible to laminate another photocurable resin on a laminated body of glass / photocurable resin (cured product), and a large number of lenses can be formed by such a laminated body. The optical system can be made thinner by consolidating it into one lens.
The above-mentioned mold releasability, fine transferability, substrate / photocurable resin adhesion, and the like may be collectively referred to as photoimprintability.

On the other hand, in the above-mentioned various transparent resins, not only transparency, low optical distortion and low specific gravity, but also optical performance such as refractive index and Abbe number are important, and due to the diversification of lenses in recent years, extremely high refractive index and A resin having a low refractive index or an extremely low Abbe number or high Abbe number is required. For example, among the optical elements that enable naked-eye 3D, there is an optical element in which a resin lens having a high refractive index and a resin lens having a low refractive index are laminated, but in order to manufacture such an optical element, there is a difference in refractive index. A high / low refractive index resin having a refractive index of 0.1 or more is required, and in order to enable naked eye 3D in a wide wavelength range, both resins are required to have a high Abbe number (low color dispersion).
The Abbe number is a value representing the wavelength dependence of the refractive index. Generally, according to JIS Z 8120, 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. 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, a resin having extremely low color dispersion, and specifically, a resin having an Abbe number of νD55 or more is required. Further, in the hybrid lens, not only a high Abbe number but also an optical imprint material having an extremely low refractive index is desired for the purpose of reducing interfacial reflection with the air layer. Specifically, it is a photocurable composition that 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 to this demand, conventionally, a resin for forming a lens has been developed mainly for a lens having a high refractive index and a high Abbe number for the purpose of shortening the focal length and reducing the color dispersion as a single lens. However, in recent years, hybrid lenses are also required to have a resin having a low refractive index and an extremely high Abbe number.
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). 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, in general, 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 fluororesin is known. Although some fluororesins have high transparency, they are usually coating materials that form a thin film, and it is difficult to form a relatively thick lens. Further, acrylate-based compounds and epoxy-based compounds having a fluorinated alkyl group can be lightly / thermally cured, but generally have poor curability, so that the refractive index and Abbe number of the obtained cured product are stable. Furthermore, because the water and oil repellency is impaired, it does not adhere to a base material such as glass, and it is easily repelled from the surface of the mold, it is not possible to manufacture a hybrid lens with a highly accurate aspherical shape or fine shape. Have difficulty.

Further, in recent years, there has been a demand for a resin having a controlled partial dispersion ratio in addition to a high Abbe number and a low refractive index. The partial dispersion ratio is a value representing the wavelength dependence of the refractive index in a specific wavelength region. 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 formula 4.
[Equation 4] Partial dispersion ratio θcT = (nC-nT) / (nF-nC)
Similarly, the partial dispersion ratio in each wavelength range is defined with the partial dispersion (nF-nC) as the denominator.

Among the partial dispersion ratios, the partial dispersion ratio θgF in the blue region is important, and in order to improve the fineness of the display or the imaging sensor, a lens material having a high partial dispersion ratio θgF is required. However, improving the partial dispersion ratio θgF is more difficult than improving the Abbe number. The reason is that it is necessary to design a composition that enhances only the refractive index nG of blue 436 nm. In particular, there is currently no known resin having a high Abbe number and a low refractive index but a high partial dispersion ratio of θgF. Even glass with a wide range of optical performance has an Abbe number of νD55 or more, a refractive index of nD1.5 or less, and a partial dispersion ratio of θgF of 0.5 or more. The maximum value of 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 it with another monomer has been proposed (for example). , Patent Document 1.).
Further, a lens obtained by polymerizing and curing a light / thermosetting composition containing a specific di (meth) acrylate has been proposed (for example, Patent Document 2).
Further, 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 has been proposed (for example, Patent Document 3).
Further, it is disclosed that a specific photocurable composition provides a cured product capable of photoimprinting and having a high Abbe number (for example, Patent Document 4).
Further, it is disclosed that a specific photocurable composition provides a cured product having a high Abbe number and a low refractive index (for example, Patent Documents 5 and 6).
Further, it is disclosed that a specific composition provides 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). 8.).
Further, it is disclosed that a specific photocurable composition is useful for adjusting the refractive index and is useful for manufacturing a laminated optical member (for example, Patent Document 9).
Further, as a photocurable composition for photoimprinting, a photocurable composition having excellent transfer accuracy has been proposed (for example, Patent Document 10).

Japanese Unexamined Patent Publication No. 61-73705 Japanese Unexamined Patent Publication No. 2-141702 Japanese Unexamined Patent Publication No. 4-366115 Japanese Unexamined Patent Publication No. 2010-150489 Japanese Unexamined Patent Publication No. 2017-141356 Japanese Unexamined Patent Publication No. 2017-141357 Special Table 2003-506499 Gazette Special Table 2011-237491 Japanese Unexamined Patent Publication No. 2009-48184 Japanese Unexamined Patent Publication No. 2013-36027

However, with the thermoplastic resin disclosed in Patent Document 1, a lens cannot be formed by an optical imprint 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, although it has a high Abbe number, it has a high refractive index, which makes it difficult to meet recent optical designs.
Further, even when the light / thermosetting composition disclosed in Patent Document 2 is used, the maximum Abbe number is 54 and the refractive index is high. Further, 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 also exceeds 1.5. Further, since a monomer containing a fluorinated alkyl group is an essential component, photocuring is difficult and thermosetting also takes a long time (16 hours in the example).
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 time are required for photocuring (Example is about 8 minutes at 15 J). ), It is inferior in productivity.
Further, when the photocurable composition disclosed in Patent Documents 5 and 6 is used, a cured product having an Abbe number of 57 can be obtained, but the refractive index is 1.5 or more, and a large amount of light is used for photocuring. In short, it is hard to say that it is excellent in productivity (Examples are 4J and 5J).
Further, when the composition disclosed in Patent Document 7 is used, a cured product having an Abbe number of 57 and a refractive index of 1.5 or less can be obtained, but it is necessary to perform thermal polymerization after prepolymerization with light. It is hard to say that it is photocurable.
Further, the photocurable composition disclosed in Patent Document 8 is obtained only as a cured product having an Abbe number of 35 or less, and has a partial dispersion ratio of θgF of 0.47 or less. Further, the dispersion solvent is an essential component, and at the time of photo-curing, the dispersion solvent must be removed and the composition must be melted by heating. Further, since a fluorine-based monomer is used, the compatibility with other components is poor, white turbidity and precipitation tend to occur, and the photocurability tends to be poor. Generally, a photocurable composition is required to be cured with a light amount of about J, but in the examples of the present patent document, the cured light amount exceeds 20J despite the thin film having a thickness of 12.5 μm. Even so, the result is that the refractive index varies (irradiation sensitivity).
Further, in 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 fluorinated alkyl group-containing acrylate is used to reduce the refractive index, so that a PET film is used. Although adhesion to a base material can be obtained, adhesion to a glass base material cannot be obtained, and it tends to be difficult to manufacture a hybrid lens.
Further, even in the photocurable composition disclosed in Patent Document 10, it is difficult to obtain a cured product having a high Abbe number. Further, since it 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, and the durability as a lens is inferior.

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

The present invention is a photocurable composition that forms a cured product that is a low-viscosity liquid under such a background, has a high Abbe number, a low refractive index, and a high partial dispersion ratio θgF. It forms a cured product with an excellent balance of light weight, transparency, low optical distortion, fine shape transferability, adhesion to the substrate, and peelability from the mold, and lens formation, especially photointensity. 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 diligent 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). The weight ratio (A / B) of the photocurable composition is 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 invention has been completed by finding that a product solves the above-mentioned problems.
(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) Photopolymerization initiator.

The photocurable composition of the present invention is a photocurable composition which is a low-viscosity liquid and 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 with an excellent balance of light weight, transparency, low optical strain, fine shape transferability, adhesion to the substrate, and peelability from the mold, and is highly produced by the optical imprint method. It is useful for manufacturing accurate hybrid lenses.

Further, among the above photocurable compositions, when 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, light is emitted. It will be useful for manufacturing high-precision hybrid lenses by the imprint method.

The present invention will be described in detail below, and these are examples of desirable embodiments.
In the present invention, (meth) acrylic means acrylic or methacrylic, (meth) acryloyl means acryloyl or methacrylic, 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) Photopolymerization initiator.

Each component constituting such a photocurable composition will be sequentially described below.

<Ingredient (A)>
In the present invention, the urethane (meth) acrylate used as the component (A) has excellent quick-curing properties and is an effective component for ensuring adhesion to the 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, or a hydroxyl group-containing (meth) acrylate-based compound may be reacted. You may use the one obtained by.

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

Among these, a polyalkylene glycol-based compound other than polyethylene glycol is preferable in terms of reducing the water absorption of the cured product, and more preferably, the polymer represented by the above general formula 5 is used in terms of increasing the number of abbreviations 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, and particularly preferably, a point of peelability of the cured product from the mold. Therefore, it is a polymer of polytetramethylene glycol, particularly preferably a polymer of polytetramethylene glycol having a molecular weight of 500 to 1500 in terms 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, norbornan isocyanatomethyl, and 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 can be mentioned. Among them, isophorone diisocyanate and hydrogenated diphenylmethane diisocyanate are preferable in terms of reducing the water absorption of the cured product, and more preferably, isophorone diisocyanate is used in terms 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-. Examples thereof include (meth) acryloyloxypropyl (meth) acrylate, pentaerythritol tri (meth) acrylate, and dipentaerythritol penta (meth) acrylate. Among these, 2-hydroxyethyl (meth) acrylate and pentaerythritol tri (meth) acrylate are preferable from the viewpoint of low cost.

As a method for producing a urethane (meth) acrylate, usually, the above-mentioned polyalkylene glycol-based compound, polyisocyanate-based compound, and hydroxyl group-containing (meth) acrylate-based compound may be charged into a reactor all at once or separately and reacted. A method of reacting a hydroxyl group-containing (meth) acrylate compound with a reaction product obtained by reacting an alkylene glycol compound and a polyisocyanate compound in advance is effective in terms of reaction stability and reduction of by-products. It is useful.

Examples of commercially available urethane (meth) acrylates as the above component (A) include "UA-160TM" and "UA-1100H" manufactured by Shin Nakamura Chemical Industry 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. By setting the Abbe number νD of the urethane (meth) acrylate to a lower limit value or more, the Abbe number νD of the cured product can be improved. In general, the upper limit of the Abbe number νD of urethane (meth) acrylate is 100.

The refractive index nD of the urethane (meth) acrylate is preferably 1.5 or less, more preferably less than 1.5, still more preferably 1.49 or less, and on the other hand, 1.4 or more. It is preferable, and more preferably 1.45 or more. By setting the refractive index nD of the urethane (meth) acrylate to an upper limit value or less, the refractive index nD of the cured product can be reduced. In general, the lower limit of the refractive index nD of urethane (meth) acrylate is 1.3.

Further, it is preferable that the urethane (meth) acrylate 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 in terms of further low water absorption, and particularly preferably, it does not contain an aromatic ring in terms of light resistance of the cured product. The urethane (meth) acrylate can be used alone or in combination of two or more.

<Ingredient (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 reducing the refractive index. Not only is it a component of the above, but it is also 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 compound, it becomes possible to form a hybrid lens by an optical imprint 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 on the weight reduction and the low refractive index of the cured product is not remarkable. The reason is that the obtained cured product forms a highly crosslinked structure, so that the atom or atomic group becomes denser. This tendency is the same for trifunctional or higher functional (meth) acrylate compounds having a propylene glycol chain.

The propylene glycol mono (meth) acrylate-based compound of the component (B) is not particularly limited as long as it is represented by the following formula 1, and known compounds 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. Dipropylene glycol mono (meth) acrylate compound, tripropylene glycol monomethyl ether mono (meth) acrylate, tripropylene glycol monoethyl ether mono (meth) acrylate, tripropylene glycol monopropyl ether mono (meth) acrylate, etc. Tetrapropylene glycol mono (meth) such as glycol mono (meth) acrylate compound, tetrapropylene glycol monomethyl ether mono (meth) acrylate, tetrapropylene glycol monoethyl ether mono (meth) acrylate, tetrapropylene glycol monopropyl ether mono (meth) acrylate. Pentapropylene glycol mono (meth) acrylate such as meta) acrylate compound, pentapropylene glycol monomethyl ether mono (meth) acrylate, pentapropylene glycol monoethyl ether mono (meth) acrylate, pentapropylene glycol monopropyl ether mono (meth) acrylate. Examples include system compounds.

Among these, tripropylene glycol monomethyl ether mono (meth) acrylate, tripropylene glycol monoethyl ether mono (meth) acrylate, tripropylene glycol monopropyl ether mono (meth) acrylate, etc. are used in terms of reducing the number of cured products. Tripropylene glycol mono (meth) acrylate compounds are preferred, and more preferably tripropylene glycol monomethyl ether mono (meth) acrylates and tripropylene glycol monoethyl ether mono (meth) in terms of the viscosity of the photocurable composition. Acrylate is preferred. The propylene glycol mono (meth) acrylate compound can be used alone or in combination of two or more.

Examples of commercially available examples of the propylene glycol mono (meth) acrylate-based compound as the component (B) include "AM-30PG" manufactured by Shin-Nakamura Chemical Industry 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 compound to the lower limit or more, the Abbe number νD of the cured product can be improved.

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, still more 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 compound to an upper limit value 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 about the same. Since it is larger than the atomic group volume of the ethylene glycol chain or trimethylene glycol chain having a molecular weight, it is presumed that 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 component (A) and the component (B) in the photocurable composition in the present invention is 70% by weight or more, preferably 75% by weight or more, and more preferably 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 higher than the lower limit, a photocurable composition capable of forming a cured product having a high Abbe number and a low refractive index can be obtained and is lightweight. It is possible to form a cured product having an excellent balance of transparency, low optical strain, adhesion to a substrate, and releasability from a mold.

The compounding ratio (A / B) of (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. It is 40/60. By setting the blending amount of the component (A) to be equal to or higher than the lower limit value, the adhesion to the base material or the molding die can be improved, and conversely, by setting the blending amount to the upper limit value or lower, the peelability from the molding die can be improved. Can be improved. Further, by setting the blending amount of the component (B) to the lower limit value or more, the photocurable composition can be made into a low-viscosity liquid, and the cured product can be made lighter. On the contrary, the photocurability can be improved by setting the value to the upper limit or less.

<Ingredient (C)>
In the present invention, the photopolymerization initiator used as the component (C) may be any as long as it generates 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-isopropylene phenyl) -2-hydroxy-2-methylpropane-1-one, 1- (4-dodecylphenyl) -2-hydroxy-2-methylpropane-1-one, 4- (2) -Hydroxyethoxy) -phenyl (2-hydroxy-2-propyl) ketone, 1-hydroxycyclohexylphenyl ketone, 2-methyl-1- [4- (methylthio) phenyl] -2-morpholinopropane-1, benzoin, benzoylmethyl Ether, benzoin ethyl ether, benzoin isopropyl ether, benzoin isobutyl ether, benzyl dimethyl ketal, benzophenone, benzoyl benzoic acid, methyl benzoyl benzoate, 4-phenylbenzophenone, hydroxybenzophenone, 4-benzoyl-4'-methyldiphenylsulfide, 3, 3'-dimethyl-4-methoxybenzophenone, thioxanson, 2-chlorthioxanson, 2-methylthioxanson, 2,4-dimethylthioxanson, isopropylthioxanson, camphorquinone, dibenzosberon, 2-ethylanthra Kinone, 4', 4 "-diethylisophthalofenone, 3,3', 4,4'-tetra (t-butylperoxycarbonyl) benzophenone, α-acyloxime ester, methylphenylglycilate, 9,10- Examples thereof include phenanthrene quinone, 4- (2-hydroxyethoxy) phenyl- (2-hydroxy-2-propyl) ketone, among these, 2,4,6-trimethylbenzoyldiphenylphosphine oxide and 1-. Hydroxycyclohexylphenyl ketones are preferred.

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

Further, as an auxiliary agent for the photopolymerization initiator, for example, triethanolamine, triisopropanolamine, 4,4'-dimethylaminobenzophenone (Mihiler ketone), 4,4'-diethylaminobenzophenone, 2-dimethylaminoethylbenzoic acid, etc. Ethyl 4-dimethylaminobenzoate, ethyl 4-dimethylaminobenzoate (n-butoxy), isoamyl 4-dimethylaminobenzoate, 2-ethylhexyl 4-dimethylaminobenzoate, 2,4-diethylthioxanson, 2, It is also possible to use 4-diisopropylthioxanson 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-based compound of the component (B), a monomer copolymerizable with these components is used as an auxiliary component in the present invention. It can be blended within a range that does not impair the purpose of. The blending amount of such an auxiliary component is less than 30% by weight of the entire photocurable composition. The blending 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, An aliphatic mono (meth) acrylate such as decyl (meth) acrylate, isodecyl (meth) acrylate, dodecyl (meth) acrylate, and 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-hydroxyethyl acrylamide, and N-methylol (meth) acrylamide. Containing monofunctional (meth) acrylate;
Ether group-containing mono (meth) acrylates such as glycidyl (meth) acrylate, furfuryl (meth) acrylate, tetrahydrofurfuryl (meth) acrylate, carbitol (meth) acrylate, butoxyethyl (meth) acrylate, and acryloylmorpholin;
2- (Meta) Phosphate group-containing mono (meth) acrylate such as acryloyloxyethyl acid phosphate;
Mono (meth) acrylates containing reactive groups other than (meth) acrylate groups such as allyl (meth) acrylates and glycidyl (meth) acrylates,
An aliphatic di (meth) acrylate such as ethylene glycol di (meth) acrylate, propylene glycol di (meth) acrylate, butylene glycol di (meth) acrylate, neopentyl glycol di (meth) acrylate, and 1,6-hexanediol di (meth) acrylate. Meta) 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 , Tetrapropylene glycol di (meth) acrylate, polypropylene glycol di (meth) acrylate, ethylene glycol diglycidyl ether di (meth) acrylate, diethylene glycol diglycidyl ether di (meth) acrylate, isocyanuric acid ethylene oxide-modified diacrylate and other ether groups. 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, etc. Acryloyl 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;
2-Acryloyloxyethyl acid Phosphodiester and other phosphate group-containing di (meth) acrylates;
Trimethylol Propanetri (meth) Acrylate, Pentaerythritol Tri (Meta) Acrylate, Pentaerythritol Tetra (Meta) Acrylate, Dipentaerythritol Penta (Meta) Acrylate, Dipentaerythritol Hexa (Meta) Acrylate, Ditrimethylol Propanetetra (Meta) Acrylate, Tri (meth) acryloyloxyethoxytrimethylol propane, 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) trifunctional or higher functional (meth) acrylates such as cyclohexane;
Pentaerythritol tetrakis (β-thiopropionate), pentaerythritol tetrakis (thioglycolate), trimethylolpropanthris (β-thiopropionate), trimethylolpropanthris (thioglycolate), diethylene glycolbis (β-thio) Propylonate), Diethylene Glycolbis (thioglycolate), Triethylene Glycolbis (β-thiopropionate), Triethylene Glycolbis (thioglycolate), Dipentaerythritol Hexakis (β-thiopropionate), Dipentaerythritol Hexakis (thioglycolate), Tris [2- (β-thiopropionyloxy) ethyl] triisosianurate, Tris (2-thioglyconyloxyethyl) triisosianurate, Tris [2- (β-thio) Propionyloxyethoxy) ethyl] triisosianurate, tris (2-thioglyconyloxyethoxyethyl) triisosianurate, tris [3- (β-thiopropionyloxy) propyl] triisosianurate, tris (3-thioglyconyloxy) Examples thereof include polyfunctional thiols such as propyl) triisocyanurate.
These auxiliary components can be used alone or in combination of two or more.

Among these, ether group-containing mono (meth) acrylates such as tetrahydrofurfuryl (meth) acrylates and acryloylmorpholin, and bis (hydroxymethyl) tricyclo [ 5.2.1.0 ^2,6 ] Alicyclic di (meth) acrylates such as decane-di (meth) acrylates, aromatic di (meth) acrylates such as ethylene oxide-modified bisphenol A type di (meth) acrylates, And a mixture thereof are preferable, and more preferably, tetrahydrofurfuryl (meth) acrylate, bis (hydroxymethyl) tricyclo [5.2.1.0 ^2,6 ] decane in terms of improving the partial dispersion ratio θgF of the cured product. = Di (meth) acrylate, ethylene oxide-modified bisphenol A type di (meth) acrylate, and a mixture 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. By setting the Abbe number νD of the auxiliary component to the lower limit value or more, the Abbe number νD of the cured product can be improved. The refractive index nD of the auxiliary component is preferably 1.6 or less, more preferably 1.55 or less, still more preferably 1.5 or less. By setting the refractive index nD of the auxiliary component to an upper limit value 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 needed, but it is preferable to keep the amount of the solvent as small as possible, and it is particularly preferable that the photocurable composition is a solvent-free type. As a solvent-free type, not only does not use any solvent in the process of preparing the photocurable composition, but even if a solvent is used at the time of preparation, the solvent is removed before the photocurable composition is applied or used. However, it is preferable not to use any solvent. By making it a solvent-free type, solvent drying is not required at the time of lens formation, 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. Additives include, for example, surfactants, silane coupling agents, chain transfer agents, antioxidants, polymerization inhibitors, anti-yellowing agents, UV absorbers, infrared absorbers, fillers, brewing agents, dyes, pigments. , Oils, plasticizers, waxes, desiccants, dispersants, wetting agents, emulsifiers, gelling agents, stabilizers, defoamers, leveling agents, mold release agents, thixotropic agents, flame retardants, fillers, reinforcements Examples include agents, matting agents, cross-linking 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 properties 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 value or more, the Abbe number νD of the cured product can be improved. In general, it is often thought that if 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 photocured. The Abbe number νD of the sex 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. It is .45 to 1.47. By setting the refractive index nD of the photocurable composition to an upper limit value 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 compounding ratio of the components constituting the photocurable composition. However, the molecular interaction and the molecular association state in the composition state (mixture) also affect the Abbe number and the refractive index of the cured product. Therefore, in order to improve the prediction accuracy and the design accuracy, the composition state is used. It is important to control the Abbe number and the index of refraction. The present invention not only sets the Abbe number and the refractive index of each component in a specific range, but also sets the Abbe number and the refractive index of the entire photocurable composition 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 even more preferably 50 to 3000 mPa · s. By setting the viscosity to the lower limit value or more, the quick curing property tends to be improved, and conversely, by setting the viscosity to the upper limit value or less, the transferability of the fine shape can be improved.

The photocurable composition of the present invention preferably has a contact angle with glass of 60 ° or less. It is more preferably 10 to 60 °, still more preferably 20 to 50 °. By setting the contact angle to the upper limit or less, the adhesiveness with the glass can be improved. On the contrary, if the contact angle is excessively small, the releasability from the mold tends to decrease. The contact angle can be controlled by adjusting the type and amount of the components of the photocurable composition and at least one of the addition of the surfactant.

Next, a method of producing a laminate in which fine uneven shapes are formed on the surface by an optical imprint method using the photocurable composition will be described.

For example, when glass is used as a base material, such a laminate is produced by the following steps (1) to (4) and, if necessary, a step (5) further added.
Step (1) A step of applying the photocurable composition to a molding die having a fine uneven shape formed on the surface.
Step (2) A step of covering the photocurable composition with a glass plate.
Step (3) A step of photocuring the photocurable composition by light irradiation to obtain a laminate made of a glass plate / cured product.
Step (4) A step of peeling a laminate made of a glass plate / cured product from a molding die.
Step (5) A step of heat-treating the laminate.

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

In the step (2), it is preferable to surface-treat the glass surface with a silane coupling agent in order to improve the adhesion of the glass / cured product. Further, in order to avoid the entrainment of bubbles, the photocurable composition may be applied to a part or the entire surface on the glass side.

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

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

The step (5) is performed as necessary for the purpose of completing the polymerization of the cured product, releasing the stress strain, stabilizing the hue, and the like. When such a 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.

The method for manufacturing a laminated body has been described above by taking the case where glass is used as a base material, but the same applies to ceramics and resin films whose base material is other than glass.

Thus, a laminate made of glass / cured product is obtained.
The total thickness of the laminate is preferably 0.1 to 30 mm. It is more preferably 0.5 to 10 mm, still more preferably 1 to 5 mm. If the total thickness is too thin, the rigidity of the hybrid lens tends to be insufficient, and conversely, if it is too thick, it tends to be difficult to reduce the weight and thickness of the hybrid lens.

The thickness of the cured product layer does not have to be uniform, but is preferably 0.01 to 1 mm. It is more preferably 0.05 to 0.7 mm, 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, and conversely, if it is too thick, the productivity tends to decrease.

Such a laminate is suitable as a hybrid lens for optical components.

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 having a finely shaped surface or a three-dimensional molded product, but a flat plate formed to evaluate various characteristics. It means a molded product, and has a thickness of 1 mm as a standard thickness.

The Abbe number νD of the cured product is preferably 55 or more. It is more preferably 56 or more, still more preferably 58 or more. By setting the Abbe number νD to a lower limit value or more, the color dispersion of the lens can be reduced. Normally, the upper limit of the Abbe number of the cured product is 100.

The refractive index nD of the cured product is preferably 1.5 or less. It is more preferably 1.45 to 1.49, and even more preferably 1.46 to 1.48. By setting the refractive index nD to an upper limit value or less, interfacial reflection with the air layer can be reduced. On the contrary, if the refractive index nD is excessively small, the interfacial 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, still more preferably 0.52 to 0.7. By setting the partial dispersion ratio θgF to the lower limit value or more, the fineness of the display or the imaging sensor can be improved. In order to improve the partial dispersion ratio θgF, as described above, the photocurable composition is supplemented with tetrahydrofurfuryl (meth) acrylate and bis (hydroxymethyl) tricyclo [5.2.1.0 ^2, which are auxiliary components. ⁶ ] Examples thereof include a method of blending decane-di (meth) acrylate, ethylene oxide-modified bisphenol A type di (meth) acrylate, and a mixture thereof.

The total light transmittance of the cured product is preferably 90% or more. It is more preferably 91% or more, still more preferably 92% or more. By setting the total light transmittance to a lower limit value or more, the total light transmittance of the lens can be improved. Normally, the upper limit of the total light transmittance of the cured product is 99%.

The haze of the cured product is preferably 1% or less. It is more preferably 0.5% or less, and particularly preferably 0.3% or less. If the haze is too large, the fineness of the display tends to decrease and the sensitivity of the imaging sensor tends to decrease. The lower limit of 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 even more preferably −0.3 to +0.3. By setting the hue b * to within ± 1, the yellowness 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. It is more preferably 1 to 1.11 and even more preferably 1.05 to 1.1. By setting the specific gravity to the upper limit or less, the weight of the lens can be reduced. On the contrary, if the specific gravity is excessively small, the lens tends to float in water and it tends to be difficult to wash with water. Normally, the lower limit of the specific gravity of the cured product is 0.9.

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

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

The flexural modulus of the cured product has a different preferable range depending on whether it is used as a single lens or a hybrid lens. In the former case, a high elastic modulus is preferable, but in the latter case, in order to reduce the stress on the base material and improve the shape stability of the entire laminate, or when it is used as an intermediate layer having a three-layer structure. Has a low elastic modulus because it plays a cushioning 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 further preferably 3 GPa or more in terms of improving the rigidity of the lens.
In the latter case, it is preferably 2 GPa or less in terms of avoiding deformation of the laminated body. It is more preferably 0.001 to 2 GPa, still more preferably 0.01 to 1 GPa. As a matter of course, if the flexural modulus is excessively small, it tends to be difficult to maintain the lens shape.

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

Hereinafter, the present invention will be described in more detail with reference to examples, but the present invention is not limited to the following examples as long as the gist of the present invention is not exceeded.
In the example, "part" and "%" mean the weight standard unless otherwise specified.

The properties of the photocurable composition prepared in the examples and the prepared cured product were measured according to the measurement conditions shown below.

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

(2) Photocurable composition The photocurable photocurable composition is applied onto a molding die (a nickel stamper having a fine surface uneven shape) described later in which a spacer having a thickness of 1 mm is installed in the peripheral portion. , Cover the surface-treated white plate glass from the top, and irradiate the white plate glass surface with ultraviolet rays with a light intensity of 2 J / cm ² (illuminance 250 mw / cm ² for 8 seconds) using a high-pressure mercury lamp, and then peel off the mold. The curing condition of the photocurable composition was observed and evaluated according to the following criteria.
○ ・ ・ ・ Cured at a light intensity of 2 J / cm ² △ ・ ・ ・ Cured by increasing the light intensity to 20 J / cm ² × ・ ・ ・ Cured insufficiently in a gel or liquid state

(3) Abbe number νD
(3-1) Abbe number νD of the photocurable composition
Using a "multi-wavelength Abbe refractometer DR-M4" manufactured by Atago, the refractive indexes of the NaD line having a wavelength of 589 nm, the NaF line having a wavelength of 486 nm, and the NaC line having a wavelength of 656 nm were measured at 25 ° C. 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 the cured product
Prepare a cured product test piece with a length of 40 mm, a width of 8 mm, and a thickness of 1 mm, and use a "multi-wavelength Abbe refractometer DR-M4" manufactured by Atago Co., Ltd. at 25 ° C. at 25 ° C. The refractive index of 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 indexes according to the above equation 2.

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

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

(6) Partial dispersion ratio of cured product θgF
Prepare a cured product test piece with a length of 40 mm, a width of 8 mm, and a thickness of 1 mm, and use a "multi-wavelength Abbe refractometer DR-M4" manufactured by Atago Co., Ltd. at 25 ° C., a refractive index of nG at 436 nm and a refractive index at 486 nm. The refractive index nC at nF and 656 nm was measured, and the partial dispersion ratio θgF was calculated from these three refractive indexes according to the following formula 3.
[Equation 3] Partial dispersion ratio θgF = (nG-nF) / (nF-nC)

(7) Total light transmittance (%) of the cured product
Prepare three cured product test pieces with a length of 50 mm, a width of 50 mm, and a thickness of 1 mm, measure the total light transmittance (%) with the haze meter "NDH-2000" manufactured by Nippon Denshoku Kogyo Co., Ltd., and measure the average value of the three pieces. Was taken as the total light transmittance of the cured product.

(8) Haze of cured product (%)
Prepare three cured product test pieces of 50 mm x 50 mm x 1 mm thickness, measure the haze using the haze meter "NDH-4000" manufactured by Nippon Denshoku Kogyo Co., Ltd. in accordance with JIS K 7361, and average the three pieces. Was the haze of the cured product.

(9) Hue of cured product b *
Three cured product test pieces having a thickness of 50 mm × 50 mm × thickness of 1 mm 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 pieces was taken as the hue b * of the cured product.

(10) Restoration of cured product (nm)
Prepare a cured product test piece with a length of 100 mm, a width of 100 mm, and a thickness of 1 mm. It was used as a refraction of the cured product.

(11) Peelability of the laminated body In the evaluation of "(2) Photocuring property of the photocurable composition" above, the peeling property when the laminated body of the glass / cured product is peeled off from the mold is based on the following criteria. evaluated.
○ ・ ・ ・ Peeling without coagulation and destruction on the surface of the cured product × ・ ・ ・ Cannot be peeled off from the mold, or there is cohesive fracture on the surface of the cured product

(12) Transferability of the laminated body In the evaluation of "(11) Detachability of the laminated body", the laminated body of the glass / cured product peeled off from the mold is heat-treated at 100 ° C. for 1 hour, and then the laminated body is used. The surface of the cured product was observed under a microscope and evaluated according to the following criteria.
〇 ・ ・ ・ Transfer without breaking the fine uneven shape of the molding mold × ・ ・ ・ Transfer by breaking or distorting the fine uneven shape of the molding mold

(13) Adhesion of laminated body According to JIS K 5400 (1990 version), the adhesiveness of the cured product to the glass was evaluated by the cross-hatch method in the laminated body of the glass / cured product.
○ ・ ・ ・ No peeling of hardened material × ・ ・ ・ There is peeling of hardened material

<Example 1>
[Preparation of base material and molding]
As a base material, a white plate glass having a length of 100 mm, a width of 100 mm, and a thickness of 1 mm was prepared, and the surface of the white plate 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%).
As a molding die, a nickel stamper (surface chrome plating) having a length of 100 mm, a width of 100 mm, and a thickness of 1 mm was prepared. On the surface of the stamper, saw-shaped grooves having a width of 100 μm and a depth of 100 μm are periodically formed at a pitch of 100 μm as fine surface uneven shapes.
Further, in order to prepare a cured product test piece for evaluating various characteristics, two pieces of glass having a length of 100 mm, a width of 100 mm and a thickness of 1 mm are prepared, and the surface of the glass in contact with the photocurable composition is made of a fluorine-based material for peeling. The surface was treated with a silane coupling agent solution (manufactured by Daikin Corporation, "Optur") to prepare glass for making test pieces.

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

[Preparation of Photocurable Composition I]
60 parts of the above component (A-1) as the component (A), 40 parts of the above component (B-1) as the component (B), and 2 parts of the above component (C-1) as the component (C) at room temperature. The mixture was stirred and mixed 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 is applied onto the above-mentioned test piece-making glass in which a spacer having a thickness of 1 mm is installed in the peripheral portion, and another test piece-making glass is covered from above, and a high-pressure mercury lamp is used. Was irradiated with ultraviolet rays of 2 J / cm ² and photocured. Next, the glasses on both sides were 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.

[Preparation of laminated body I]
The obtained photocurable composition I is applied onto the above-mentioned molding mold having a spacer having a thickness of 1 mm installed in the peripheral portion, covered with a surface-treated white plate glass from above, and a white plate glass surface is covered 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 molding die was peeled off from the surface of the cured product on which the uneven shape was formed. The peelability was good. The obtained laminated glass / cured product was heat-treated at 100 ° C. for 1 hour to obtain a laminated body I. The transfer accuracy on the surface of the cured product was good.

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

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

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

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

<Example 5>
[Preparation of photocurable composition V, etc.]
Example 1 except that 37 parts of the component (A-1) are used as the component (A), 45 parts of the component (B-1) are used as the component (B), and 18 parts of the component (D-2) are used as the auxiliary component. Similarly, a photocurable composition V, a cured product test piece V, and a laminate V were obtained.
Various characteristics of the obtained photocurable composition V, cured product test piece V, and laminate V were evaluated and 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), 17 parts of the component (D-2) as the auxiliary component, and 5 parts of the component (D-3). A photocurable composition VI, a cured product test piece VI, and a laminated body VI were obtained in the same manner as in Example 1 except that a portion was used.
Various characteristics of the obtained photocurable composition VI, cured product test piece VI, and laminate VI were evaluated and shown in Tables 1 and 2.

<Comparative Example 1>
[Preparation of photocurable composition VII, etc.]
A photocurable composition VII was obtained in the same manner as in Example 1 except that 80 parts of the component (A-1) and 20 parts of the component (B-1) were used as the component (A). .. Further, in the same manner as in Example 1, photocuring was performed by irradiating with ultraviolet rays of 2 J / cm ² 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 peel off the mold from the surface of the cured product on which the fine uneven shape was formed, but the mold could not be peeled off because it was firmly adhered, and the target glass / cured product laminate VII was obtained. There wasn't.
Various characteristics of the obtained photocurable composition VII and cured product test piece VII were evaluated and shown in Tables 1 and 2. Although the desired laminate VII was not obtained as described above, Table 2 shows the evaluation of the evaluable peelability and adhesion to the glass.

<Comparative Example 2>
[Preparation of photocurable composition VIII, etc.]
The photocurable composition VIII and the cured product are the same as in Example 1 except that 20 parts of the component (A-1) are used as the component (A) and 80 parts of the component (B-1) are used as the component (B). A test piece VIII and a laminate VIII were obtained.
Various properties of the obtained photocurable composition VIII, cured product test piece VIII and laminate VIII were evaluated and 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) are used as an auxiliary component. A photocurable composition IX, a cured product test piece IX, and a laminate IX were obtained in the same manner as in Example 1 except for the above.
Various characteristics of the obtained photocurable composition IX, cured product test piece IX and laminate IX were evaluated and shown in Tables 1 and 2.

<Comparative Example 4>
[Preparation of photocurable composition X, etc.]
As the component (A), the photocurable composition is the same as in Example 1 except that 70 parts of the component (A-1) and 40 parts of the component (B-1) are replaced with 30 parts of the component (B'-2). I got X. Further, in the same manner as in Example 1, photocuring was performed by irradiating 2 J / cm ² ultraviolet rays with a high-pressure mercury lamp, but the photocurable composition X had low photocurability, so that it was in a liquid state. It remained.

<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 in the same manner as in Example 1, 2 J / cm ² ultraviolet rays were prepared using a high-pressure mercury lamp. Was irradiated and photocured. However, it was gel-like and insufficiently cured. Therefore, the photocurable composition X'was irradiated with ultraviolet rays of 20 J / cm ² to obtain a cured product test piece X'and a laminated body X'.
The cured product test piece X'had a yellowish and whitish appearance. Further, in the laminated body X', the cured product was partially peeled off from the glass.
Various properties of the obtained photocurable composition X', cured product test piece X'and laminated body X'were evaluated and shown in Tables 1 and 2. Since the refractive index nG of the cured product test piece X'at 436 nm could not be measured, the partial dispersion ratio θgF could not be calculated.

In Comparative Example 4', when the compounding ratio of the component (B'-2) was further increased (50 parts, etc.), the 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-based compound having a fluorinated alkyl group is inferior in photoimprintability.

For the photocurable compositions obtained from the above Examples and Comparative Examples, the constituent components and the contents of each component are shown in Table 1 together with the viscosity, photocurability, Abbe number, and refractive index of each component.

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 peelability, transferability, and adhesion to glass of the laminated body obtained from the above Examples and Comparative Examples from the mold.

The photocurable compositions of Examples 1 to 6 have a lower viscosity than the photocurable compositions of Comparative Example 1, form a cured product having an excellent partial dispersion ratio of θgF, and have photoimprintability (peeling). It can be seen that it is excellent in property, transferability, and adhesion to glass). Further, it can be seen that a cured product having a partial dispersion ratio of θgF is formed as compared with the photocurable composition of Comparative Example 2, and the adhesion to glass is excellent. Further, it can be seen that a cured product having a lower specific gravity and an excellent partial dispersion ratio of 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', it is excellent in photocurability and photoimprintability, and has low specific gravity, high Abbe number, high total light transmittance, low haze, hue, and retardation. It can be seen that it forms an excellent cured product.
Further, when the cured products of Examples 1 to 6 are compared with each other, it can be seen that Examples 5 and 6 using the specific auxiliary components 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 obtained cured product has excellent optical performance such as a high Abbe number, a low refractive index, and a high partial dispersion ratio θgF. , Lens forming material, optical imprint material, coating agent, adhesive, sealing agent, adhesive, paint, ink, coating binder and the like, which are useful as various film forming materials. In particular, it is also suitably used as a lens forming agent for forming microlenses such as a lenticular lens, a Fresnel lens, and a microlens array on a substrate. Further, the laminate of the base material / cured product produced by using the photocurable composition is a light guide plate for a display, an optical sheet / film, an imaging sensor, a signage, an in-vehicle use, an optical communication, and a sun. It is useful as an optical component for batteries, lighting, memory, etc.

Claims (2)

A photocurable composition for forming a lens, which contains the following components (A), (B), and (C), and has a weight ratio (A / B) of the component (A) to the component (B). A photocurable composition having a composition of 25/75 to 75/25, wherein the total amount of the components (A) and (B) is 70% by weight or more of the total amount of the 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) 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. thing.