Ultraviolet curable composition for light shielding, light shielding film, and method for manufacturing an article having the light shielding film

Abstract

The present invention discloses an ultraviolet curable composition for light shielding, which comprises a polymerizable monomer, an organic black pigment, and a particulate light scattering material. An article having a light shielding film with high light shielding property can be manufactured by a method including the following steps: a step of forming a resin film containing the ultraviolet curable composition for light shielding on a substrate; and a step of curing the resin film by irradiation with ultraviolet rays to thereby form a light shielding film of a cured product containing the ultraviolet curable composition for light shielding.

Description

Technical Field

[0001] The present invention relates to an ultraviolet curable composition for light shielding, a light shielding film, and a method for manufacturing an article having the light shielding film. Background Art

[0002] A light shielding film provided in various display devices such as a liquid crystal display device is sometimes formed using a thermosetting or ultraviolet curable ink containing a black pigment such as carbon black (for example, Patent Document 1). In terms of suppressing damage to peripheral components of the light shielding film or a printing device and printing accuracy, etc., the ultraviolet curable ink is more advantageous than the thermosetting ink.

[0003] Prior Art Documents

[0004] Patent Documents

[0005] Patent Document 1: Japanese Patent Application Laid-Open No. 2009-37234 Summary of the Invention

[0006] Technical Problem to be Solved by the Invention

[0007] Although a light shielding film containing carbon black has high light shielding property, since carbon black substantially does not transmit ultraviolet rays, it is difficult for an ultraviolet curable composition (or ink) containing carbon black to have sufficient ultraviolet curability. By using an organic black pigment that transmits ultraviolet rays to some extent, improvement in ultraviolet curability can be expected, but in this case, there is a tendency for the light shielding property of the light shielding film to be insufficient.

[0008] Therefore, one aspect of the present invention provides an ultraviolet curable composition for light shielding that can form a light shielding film having sufficient ultraviolet curability and high light shielding property.

[0009] Means for Solving the Technical Problem

[0010] One aspect of the present invention provides an ultraviolet curable composition for light shielding containing a photopolymerizable monomer, an organic black pigment, and a particulate light scattering material.

[0011] Another aspect of the present invention provides a light shielding film containing a cured product of the above ultraviolet curable composition for light shielding.

[0012] Still another aspect of the present invention provides a method for manufacturing an article having a light shielding film including the following steps: a step of forming a resin film containing the above ultraviolet curable composition for light shielding on a substrate; and a step of forming a light shielding film containing a cured product of the above ultraviolet curable composition for light shielding by irradiating the resin film with ultraviolet rays.

[0013] Advantageous Effects of the Invention

[0014] According to one aspect of the present invention, there is provided a UV-curable composition for light shielding that can form a light shielding film having sufficient UV curability and high light shielding properties. Detailed Description of Embodiments

[0015] Hereinafter, some embodiments of the present invention will be described in detail. However, the present invention is not limited to the following embodiments. In this specification, “(meth)acryloyl” means methacryloyl or acryloyl. The same applies to other similar expressions.

[0016] The UV-curable composition for light shielding according to one embodiment includes a polymerizable monomer, an organic black pigment, and a particulate light scattering material. This UV-curable composition can be used to form a light shielding film. The UV-curable composition according to this embodiment can be an ink (e.g., an inkjet printing ink) for forming a light shielding film by a printing method.

[0017] The polymerizable monomer is composed of one or more compounds having one or more polymerizable functional groups. The polymerizable functional group can be an ethylenically unsaturated group. The polymerizable monomer can be a compound having one or more (meth)acryloyl groups. The compound having a (meth)acryloyl group used as the polymerizable monomer can be an alkyl (meth)acrylate, (meth)acrylic acid, (meth)acrylamide, N-alkyl (meth)acrylamide, N,N-dialkyl (meth)acrylamide, or a combination of two or more selected from these. The alkyl group in the alkyl (meth)acrylate, N-alkyl (meth)acrylamide, and N,N-dialkyl (meth)acrylamide can have a substituent. Examples of the substituent include an aryl group, a hydroxyl group, a carboxyl group, a glycidyl group, and an amino group.

[0018] The polymerizable monomer can be liquid at room temperature (25°C). The UV-curable composition containing the liquid polymerizable monomer can be solvent-free or can have a fluidity suitable for printing. The polymerizable monomer can also be a monofunctional acrylic monomer having one (meth)acryloyl group, a polyfunctional acrylic monomer having two or more (meth)acryloyl groups, or a combination of these.

[0019] The monofunctional acrylic monomer is not particularly limited, and specific examples thereof include (meth)acrylate esters having an alkyl group with 1 to 18 carbon atoms such as methyl (meth)acrylate, ethyl (meth)acrylate, n-butyl (meth)acrylate, isobutyl (meth)acrylate, tert-butyl (meth)acrylate, n-pentyl (meth)acrylate, n-hexyl (meth)acrylate, n-octyl (meth)acrylate, isooctyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, dodecyl (meth)acrylate, and stearyl (meth)acrylate; (meth)acrylate esters having a hydroxyl group such as 2-hydroxyethyl (meth)acrylate, 1-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 3-hydroxypropyl (meth)acrylate, 1-hydroxypropyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate, 3-hydroxybutyl (meth)acrylate, 2-hydroxybutyl (meth)acrylate, and 1-hydroxybutyl (meth)acrylate; (meth)acrylate esters having a glycidyl group such as glycidyl (meth)acrylate, α-ethylglycidyl (meth)acrylate, α-propylglycidyl (meth)acrylate, α-butylglycidyl (meth)acrylate, 2-methylglycidyl (meth)acrylate, 2-ethylglycidyl (meth)acrylate, 2-propylglycidyl (meth)acrylate, 3,4-epoxybutyl (meth)acrylate, 3,4-epoxyheptyl (meth)acrylate, α-ethyl-6,7-epoxyheptyl (meth)acrylate, and 3,4-epoxycyclohexylmethyl (meth)acrylate; and (meth)acrylate esters having an alicyclic group such as cyclopentyl (meth)acrylate, cyclohexyl (meth)acrylate, methylcyclohexyl (meth)acrylate, trimethylcyclohexyl (meth)acrylate, norbornyl (meth)acrylate, norbornylmethyl (meth)acrylate, phenylnorbornyl (meth)acrylate, cyanonorbornyl (meth)acrylate, isobornyl (meth)acrylate, bornyl (meth)acrylate, menthyl (meth)acrylate, fenchyl (meth)acrylate, adamantyl (meth)acrylate, dimethyladamantyl (meth)acrylate, tricyclo[5.2.1.0 2.6 dec-8-yl (meth)acrylate, tricyclo[5.2.1.0 2.6 dec-4-ylmethyl (meth)acrylate, and cyclodecyl (meth)acrylate.

[0020] The curable composition may contain a liquid photopolymerizable monomer and a polymer and / or an oligomer. The polymer and the oligomer may have a photopolymerizable group. In the present specification, the polymer and the oligomer having a photopolymerizable group are regarded as a photopolymerizable monomer.

[0021] The content of the photopolymerizable monomer may be 10% by mass or more, 20% by mass or more, 30% by mass or more, and may be 95% by mass or less based on the mass of the ultraviolet curable composition. The content herein means the total content of these when two or more compounds are used as the photopolymerizable monomer.

[0022] The ultraviolet curable composition for light shielding may further contain a photoinitiator. The photoinitiator is a compound that initiates a polymerization reaction of the photopolymerizable monomer by absorbing ultraviolet light. The photoinitiator may be, for example, a photo radical polymerization initiator or a photo cationic polymerization initiator, and particularly may be a photo radical polymerization initiator. From the viewpoint of ultraviolet curability, the photoinitiator may contain a compound that exhibits a maximum value in the absorption spectrum in the range of 300 to 400 nm. A composition containing a photopolymerizable monomer, an organic black pigment, and a particulate light scattering material may be mixed with a photoinitiator for use in manufacturing the ultraviolet curable composition for light shielding.

[0023] The photo radical polymerization initiator is not particularly limited. For example, it can be an α-cleavage type compound or a hydrogen abstraction type compound, or it can also be a bimolecular radical polymerization initiator. As examples of the photo polymerization initiator, there can be mentioned aromatic ketone compounds such as benzophenone, 4-methylbenzophenone, N,N,N’,N’-tetramethyl-4,4’-diaminobenzophenone (Michler's ketone), N,N-tetraethyl-4,4’-diaminobenzophenone, 4-methoxy-4’-dimethylaminobenzophenone, α-hydroxyisobutyrophenone, 2-ethylanthraquinone, tert-butylanthraquinone, 1,4-dimethylanthraquinone, 1-chloroanthraquinone, 2,3-dichloroanthraquinone, 3-chloro-2-methylanthraquinone, 1,2-benzanthraquinone, 2-phenylanthraquinone, 1,4-naphthoquinone, 9,10-phenanthrenequinone, thioxanthone, 2-chlorothioxanthone, 1-hydroxycyclohexyl phenyl ketone, 2,2-dimethoxy-1,2-diphenylethane-1-one, 1-[4-(2-hydroxyethoxy)phenyl]-2-hydroxy-2-methyl-1-propan-1-one, and 2-hydroxy-2-methyl-1-phenylpropan-1-one; benzoin compounds such as benzoin, methyl benzoin, and ethyl benzoin; benzoin ether compounds such as benzoin methyl ether, benzoin ethyl ether, benzoin isobutyl ether, and benzoin phenyl ether; benzil; 2,2-diethoxyacetophenone; benzyl dimethyl ketal; ester compounds of β-(acridin-9-yl)(methyl)acrylic acid; acridine compounds such as 9-phenylacridine, 9-pyridylacridine, and 1,7-diacridinoheptane; 2,4,5-triaryl imidazole dimers such as 2-(o-chlorophenyl)-4,5-diphenylimidazole dimer, 2-(o-chlorophenyl)-4,5-bis(m-methoxyphenyl)imidazole dimer, 2-(o-fluorophenyl)-4,5-diphenylimidazole dimer, 2-(o-methoxyphenyl)-4,5-diphenylimidazole dimer, 2-(p-methoxyphenyl)-4,5-diphenylimidazole dimer, 2,4-bis(p-methoxyphenyl)5-phenylimidazole dimer, 2-(2,4-dimethoxyphenyl)-4,5-diphenylimidazole dimer, and 2-(p-methylthiophenyl)-4,5-diphenylimidazole dimer; 2-benzyl-2-dimethylamino-1-(4-morpholinophenyl)-1-butanone; 2-methyl-1-[4-(methylthio)phenyl]-2-morpholino-1-propanone; bis(2,4,6-trimethylbenzoyl)phenylphosphine oxide; and poly(2-hydroxy-2-methyl-1-(4-(1-methylethenyl)phenyl)acetone). These photo polymerization initiators can be used alone or in combination of two or more.

[0024] The content of the photo polymerization initiator is, based on the mass of the ultraviolet curable composition, for example, 0.1 to 10% by mass. The content here refers to the total content of these when two or more compounds are used as the photo polymerization initiator.

[0025] The organic black pigment is black particles containing an organic pigment, which can be selected from pigments commonly used as black pigments. The organic black pigment can be, for example, at least one selected from the group consisting of perylene-based pigments (perylene black), lactam-based pigments (lactam black), aniline black, cyanine black, lignin black, and RGB black.

[0026] The average particle size (dispersion particle size) of the organic black pigment dispersed in the ultraviolet curable composition is not particularly limited, and can be, for example, 0.01 to 1.0 μm.

[0027] From the viewpoint of appropriate light shielding property of the light shielding film, the content of the organic black pigment can be 0.5% by mass or more, or 1.0% by mass or more, based on the mass of the ultraviolet curable composition, and can be 50% by mass or less. The content here refers to the total content of these when two or more organic black pigments are used.

[0028] The light scattering material is composed of a plurality of particles. These plurality of particles are usually dispersed in the ultraviolet curable composition. The average particle size of the light scattering material can be 0.05 μm or more, and can be 5.0 μm or less, 4.0 μm or less, 3.0 μm or less, 2.0 μm or less, or 1.0 μm or less. From the viewpoint of appropriate light shielding property of the light shielding film, the average particle size of the light scattering material can be 0.1 to 1.0 μm. The average particle size of the light scattering material can be a value obtained from the volume-based particle size distribution obtained by the laser diffraction / scattering method.

[0029] The light scattering material can contain, for example, silicone particles, silica particles, or a combination thereof. The light scattering material can also contain silicone particles and other particles selected from silica particles, alumina particles, and titanium oxide particles. Part or all of the light scattering material can be hollow particles. The silicone particles are particles containing silicone having a polysiloxane chain, and the silicone can have a structure in which the polysiloxane chain is crosslinked, or can be a polyorganosilsesquioxane. The silicone particles can also be composite particles having a core particle and a film formed on the surface of the core particle and containing polyorganosilsesquioxane, and the core particle contains silicone having a polysiloxane chain.

[0030] The content of the light scattering material can be 0.5% by mass or more, or 1.0% by mass or more, based on the mass of the ultraviolet curable composition, and can be 10% by mass or less, 9.0% by mass or less, 8.0% by mass or less, 7.0% by mass or less, 6.0% by mass or less, 5.0% by mass or less, or 4.0% by mass or less. The content here refers to the total content of these when two or more light scattering materials are used.

[0031] The ultraviolet curable composition can be a solvent-free composition that substantially does not contain a solvent. More specifically, the content of the solvent can be 1.0% by mass or less, or 0% by mass, based on the mass of the ultraviolet curable composition. A composition (ink) that substantially does not contain a solvent is advantageous, for example, in preventing damage to components around the light-shielding film, preventing damage to the printing apparatus, and forming a high-precision light-shielding film.

[0032] The cured film formed by film curing of the ultraviolet curable composition has high light-shielding properties. For example, the OD value (optical density) of the formed cured film can be 1.5 or more, 2.0 or more, or 2.5 or more. The OD value here is a value calculated based on the average transmittance of light with wavelengths of 400 to 700 nm for a cured film with a thickness of 130 μm ± 5 μm.

[0033] Using the ultraviolet curable composition according to the embodiments exemplified above, various articles having a light-shielding film can be manufactured. One embodiment of a method for manufacturing an article having a light-shielding film includes the following steps: a step of forming a resin film containing an ultraviolet curable composition on a substrate; and a step of forming a light-shielding film of a cured product of the ultraviolet curable composition by irradiating the resin film with ultraviolet light. The resin film can also be formed by printing (for example, inkjet printing) using the ultraviolet curable composition as an ink. The wavelength of the ultraviolet light used to cure the ultraviolet curable composition for forming the resin film can be 300 to 400 nm. The thickness of the resin film (light-shielding film) can be, for example, 20 to 1000 μm.

[0034] Examples of articles having a light-shielding film include an image display device, an optical sensor, and a lens.

[0035] Examples

[0036] Hereinafter, the present invention will be described in more detail with reference to examples. However, the present invention is not limited to these examples.

[0037] 1. Raw materials

[0038] 1-1. Black pigments

[0039] Organic black pigments

[0040] · Lactam-based pigments (dispersion particle size: 0.17 μm)

[0041] · Perylene-based pigments (dispersion particle size: 0.17 μm)

[0042] The transmission spectra of these lactam-based pigments and perylene-based pigments include portions with a transmittance exceeding 10% in the wavelength range of 300 to 400 nm.

[0043] Other pigments

[0044] · Carbon black (dispersion particle size: 0.15 μm)

[0045] 1-2. Light scattering materials

[0046] · Silicone particles (manufactured by Shin-Etsu Chemical Co., Ltd., product name: X-52-854, average particle size: 0.7 μm)

[0047] · Silicone particles (manufactured by Shin-Etsu Chemical Co., Ltd., product name: KMP-706, average particle size: 2.0 μm)

[0048] · Silicone composite particles (manufactured by Shin-Etsu Chemical Co., Ltd., product name: X-52-7030, average particle size: 0.8 μm)

[0049] · Silica particles (manufactured by Admatechs Co., Ltd., product name: S0-C1, average particle size: 0.3 μm)

[0050] · Silica particles (manufactured by Admatechs Co., Ltd., product name: S0-C2, average particle size: 0.5 μm)

[0051] 1-3. Photopolymerizable monomers

[0052] · 4-Hydroxybutyl acrylate (4-HBA)

[0053] 1-4. Photoinitiators for free radical polymerization

[0054] · 1-Hydroxycyclohexyl phenyl ketone (manufactured by BASF, product name: Irgacure-184)

[0055] · 4-Methyldibenzoyl (manufactured by Sort Co., Ltd., product name: SB-PI712)

[0056] 2. Ultraviolet curable composition (ink)

[0057] Example 1

[0058] 3.0 parts by mass of a lactam-based pigment was dispersed in 91.7 parts by mass of 4-hydroxybutyl acrylate to obtain a dispersion having a dispersed particle diameter of 0.17 μm of the lactam-based pigment. 2.0 parts by mass of silicone particles (X-52-854), 3.0 parts by mass of 1-hydroxycyclohexyl phenyl ketone (Irgacure-184), and 0.3 parts by mass of 4-methyldibenzoyl ketone (SB-PI712) were added to the dispersion, and the mixture was stirred at a rotation speed of 2,000 rpm for 5 minutes using a rotation-revolution mixer (THINKY CORPORATION, product name: ARE-250), thereby obtaining a UV-curable composition.

[0059] Examples 2 to 8 and Comparative Examples 1 to 3

[0060] Except as shown in Table 1, where the materials and blending amounts were changed, a UV-curable composition was prepared in the same manner as in Example 1.

[0061] 3. Production of a laminated film

[0062] Each UV-curable composition of the examples and comparative examples was applied onto a support film (polyethylene terephthalate film, manufactured by FUJIMORI KOGYO CO., LTD., product name: 75E-0010HTA) having a thickness of 75 μm with a surface subjected to a release treatment using an applicator. A protective film (polyethylene terephthalate film, manufactured by FUJIMORI KOGYO CO., LTD., product name: 50E-0010BD) having a thickness of 50 μm with a release treatment was covered on the formed resin film. The resin film was cured by irradiating ultraviolet rays (3,000 mJ / cm 2 ) from the protective film side using an ultraviolet irradiation device (manufactured by EYE GRAPHICS Co., Ltd., metal halide lamp), and a laminated film of a light-shielding film (thickness: about 130 μm) having a cured product of the UV-curable resin composition was obtained.

[0063] 4. Evaluation

[0064] 4-1. Reaction rate (UV curability)

[0065] About 1 g of each UV-curable composition of the examples and comparative examples was dropped onto a glass plate to form a resin film as a measurement sample before UV irradiation. Using a Fourier transform infrared absorption spectrometer (manufactured by SHIMADZU CORPORATION, product name: IR Spirit (QATR-S unit)), under the environment of normal temperature (25 °C), the infrared absorption spectrum of the formed resin film was measured by the ATR method under the conditions of optical resolution: 2 cm -1 , accumulation: 64 times.

[0066] A measurement sample with a size of 10 mm × 10 mm was cut out from the laminated film with a light-shielding film, and the protective film was peeled off from the measurement sample. The exposed light-shielding film was attached to a glass plate, and then the support film was peeled off from the light-shielding film. The infrared absorption spectrum of the exposed light-shielding film (measurement sample after UV irradiation) was measured using the same method as above.

[0067] In each of the obtained infrared absorption spectra, the intensity (A) of the absorption peak attributed to the acryloyl group showing a maximum near 810 cm -1 and the intensity (B) of the absorption peak attributed to the carbonyl group showing a maximum near 1720 cm -1 were determined, and the acryloyl group absorption peak ratio was calculated using the following formula.

[0068] Acryloyl group absorption peak ratio = (A) / (B)

[0069] Based on the acryloyl group absorption peak ratio α obtained from the infrared absorption spectrum of the measurement sample before UV irradiation and the acryloyl group absorption peak ratio β obtained from the infrared absorption spectrum of the measurement sample after UV irradiation, the reaction rate of the acryloyl group was calculated using the following formula. A large value of this reaction rate means that curing was efficiently carried out by ultraviolet irradiation.

[0070] Reaction rate (%) = (β / α) × 100

[0071] 4-2. OD value (light-shielding property)

[0072] Using a haze meter (manufactured by NIPPON DENSHOKU INDUSTRIES CO., LTD., product name: SH7000) with D65 as the light source, the transmittance of a light-shielding film with a size of 40 mm × 50 mm was measured at each wavelength interval of 5 nm from 400 nm to 700 nm. Based on the average value C of the transmittance at each wavelength, the OD value was calculated using the following formula. A large OD value means high light-shielding property (light-shielding ability) of the light-shielding film for visible light.

[0073] OD value = -Log 10 (C / 100)

[0074] [Table 1]

[0075]

[0076] The ultraviolet curable compositions of the respective embodiments are cured with good curability by ultraviolet irradiation, and a light-shielding film having a sufficiently high light-shielding property is formed. The light-shielding film formed from the ultraviolet curable composition of Comparative Example 1 containing an organic black pigment and not containing a light-scattering material has a low light-shielding property. The ultraviolet curable composition of Comparative Example 2 containing carbon black forms a light-shielding film having a high light-shielding property, but is insufficient in terms of curability.

Claims

1. An ultraviolet curable composition for light shielding, comprising: A polymerizable monomer; An organic black pigment containing a lactam-based pigment; and A particulate light scattering material, The average particle size of the light scattering material is 0.1 to 1.0 μm, and the light scattering material contains silicone particles.

2. The ultraviolet curable composition for light shielding according to claim 1, wherein The content of the light scattering material is 0.5 to 10% by mass based on the mass of the ultraviolet curable composition for light shielding.

3. The ultraviolet curable composition for light shielding according to claim 1 or 2, wherein The OD value of the cured film formed by curing the film of the ultraviolet curable composition for light shielding is 1.5 or more, The OD value is a value calculated based on the average transmittance of light with wavelengths of 400 to 700 nm for the cured film having a thickness of 130 μm ± 5 μm.

4. The ultraviolet curable composition for light shielding according to claim 1 or 2, which further comprises a photoinitiator.

5. A light shielding film comprising a cured product of the ultraviolet curable composition for light shielding according to any one of claims 1 to 4.

6. A method for manufacturing an article having a light shielding film, comprising the following steps: A step of forming a resin film containing the ultraviolet curable composition for light shielding according to any one of claims 1 to 4 on a substrate; and A step of forming a light shielding film containing a cured product of the ultraviolet curable composition for light shielding by irradiating the resin film with ultraviolet rays.

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