JP2023129005A - Optical laminate and method for manufacturing the same - Google Patents

Abstract

To provide an optical laminate that has antibacterial properties and antireflection properties, and has a less yellowish and neutral hue.SOLUTION: A laminate is prepared, including a base material layer, an intermediate layer laminated on at least one face of the base material layer, and an antireflection layer laminated on the intermediate layer and including silver nanoparticles. The antireflection layer may be formed of a cured product of a curable composition including silver nanoparticles. The curable composition may further include a non-fluorine-containing curable component, and inorganic filler and/or a fluorine-containing component. The intermediate layer may be formed of a cured product of a curable composition including a curable component and a (meth)acrylic leveling agent. The base material layer may include a transparent organic material. The laminate may have a chromaticity b* of reflected light of 5 or less in its absolute value. The antireflection layer may be a wet coating layer.SELECTED DRAWING: None

Description

The present disclosure relates to an optical laminate having antibacterial and antireflective properties and a method for manufacturing the same.

Silver nanoparticles have traditionally been used in various fields, and for example, in International Publication No. 2015/159517 (Patent Document 1), silver nanoparticles have been applied to functional glass used for building materials and automotive window glasses. As an antireflection film, a hard coat layer, a silver nanodisc layer containing silver nanodiscs with an average particle size of 10 to 500 nm in a binder, and a low refractive index layer are sequentially laminated on a transparent substrate as an antireflection structure. A film has been disclosed.

JP 2019-157259 A (Patent Document 2) discloses a sterilizing film that combines tungsten and nanosilver by sputtering as a film that is wear-resistant, economical, and has a high sterilizing effect. has been done.

JP 2014-238606A (Patent Document 3) describes silver nanoparticles, silicone-containing monomers, macromers, or prepolymers as an antibacterial medical device that minimizes the possibility of microbial adhesion and colony formation. A medical device, such as an antimicrobial contact lens, is disclosed that is obtained by in-mold polymerization of a polymerizable dispersion dispersed in a polymerizable fluid composition containing the present invention.

Japanese Patent Publication No. 2017-530079 (Patent Document 4) describes a glass substrate or a glass ceramic substrate whose surface is coated with a multifunctional layer having antibacterial properties, antireflection properties, and anti-fingerprint properties. A glass substrate is disclosed in which a plurality of layers having different refractive indexes are formed, ion exchange is performed with silver ions, and a layer having anti-fingerprint properties is further coated on the antireflection layer.

International Publication No. 2015/159517 JP 2019-157259 Publication JP2014-238606A Special table 2017-530079 publication

However, in the prior art, a film with antibacterial and antireflective properties derived from metal nanoparticles is not known. In addition, there is no known technology that uses silver nanoparticles to exhibit antibacterial properties by a simple method such as wet coating. Furthermore, when the film contains silver nanoparticles, there is a problem that the film becomes yellowish in color.

Therefore, an object of the present disclosure is to provide an optical laminate having antibacterial properties and antireflection properties, and a neutral hue with suppressed yellowing, and a method for manufacturing the same.

By laminating an antireflection layer containing silver nanoparticles on at least one surface of the base material layer via an intermediate layer, the present inventor has achieved antibacterial and antireflection properties as well as suppressing yellowing. The present invention was completed based on the discovery that it is possible to provide an optical laminate having a neutral hue.

That is, the laminate of the present disclosure includes a base layer, an intermediate layer laminated on at least one surface of the base layer, and an antireflection layer laminated on the intermediate layer and containing silver nanoparticles. including. The antireflection layer may be formed of a cured product of a curable composition containing silver nanoparticles. The curable composition may further include a fluorine-free curable component and an inorganic filler and/or a fluorine-containing component (particularly an inorganic filler and a fluorine-containing component). The fluorine-free curable component may be a polyfunctional (meth)acrylate having 3 to 6 (meth)acryloyl groups. The inorganic filler may be hollow silica. The fluorine-containing component may be a fluorine-containing curable component. The intermediate layer may be formed of a cured product of a curable composition containing a curable component and a (meth)acrylic leveling agent. The base layer may contain a transparent organic material, in particular a polyester or a cellulose ester. In the laminate, the absolute value of the chromaticity b ^* of reflected light may be 5 or less. The antireflection layer may be a wet coating layer.

The present disclosure also includes a method for manufacturing the laminate, including an antireflection layer forming step of laminating an antireflection layer on the intermediate layer. In the antireflection layer forming step, a curable composition containing silver nanoparticles may be wet coated.

The present disclosure also includes a display device including the laminate.

In the present disclosure, since the antireflection layer containing silver nanoparticles is laminated on at least one surface of the base material layer via the intermediate layer, it is possible to impart antibacterial and antireflection properties to the laminate, and the yellow color You can adjust the color to a neutral color with a subdued taste. In particular, by forming an anti-reflective layer with a specific curable composition on a specific intermediate layer, it is possible to efficiently manufacture a transparent anti-reflective layer with suppressed yellowing by wet coating. It is also excellent in sex.

[Anti-reflection layer]
The laminate (optical laminate) of the present disclosure has an antireflection layer (low refractive index layer) laminated on the intermediate layer. This antireflection layer contains silver nanoparticles and has antibacterial properties.

The average primary particle size of the silver nanoparticles may be 100 nm or less, for example 0.5 to 100 nm, preferably 0.5 to 80 nm, more preferably 1 to 70 nm, more preferably 5 to 60 nm, most preferably 10 nm. ~50 nm. If the average primary particle diameter is too large, there is a risk that the antireflection properties will deteriorate.

In the present disclosure, the average primary particle diameter of silver nanoparticles can be determined as an average value of ten arbitrary particles based on scanning electron microscopy (SEM) observation results.

The surface of the silver nanoparticles may be coated with a protective agent. Examples of the protective agent include aliphatic amines and/or aliphatic carboxylic acids (particularly aliphatic amines).

The proportion of silver nanoparticles in the antireflection layer may be 0.01% by mass or more, for example 0.01 to 30% by mass, preferably 0.05 to 10% by mass, more preferably 0.1 to 5% by mass. % by weight, more preferably 0.3-3% by weight, most preferably 0.5-1.5% by weight. If the proportion of silver nanoparticles is too small, there is a risk that antibacterial properties will decrease.

The refractive index of the antireflection layer may be 1.37 or higher, for example 1.37 to 1.45, preferably 1.37 to 1.4, more preferably 1.37 to 1.39, more preferably It is 1.37 to 1.38. If the refractive index is too high, there is a risk that the antireflection properties will be reduced. Note that in the present disclosure, the refractive index can be measured in accordance with JIS K7142.

The thickness (average thickness) of the reflective refractive index layer is, for example, 50 to 300 nm, preferably 60 to 150 nm, more preferably 80 to 120 nm, and more preferably 90 to 110 nm.

The antireflection layer only needs to contain silver nanoparticles, and may be made of a low refractive index resin [for example, methylpentene resin, diethylene glycol bis(allyl carbonate) resin, polyvinylidene fluoride (PVDF), polyvinyl fluoride (PVF), etc.]. Although the layer may be formed of a fluororesin or the like, from the viewpoint of mechanical properties, etc., it is preferably a layer formed of a cured product of a curable composition containing silver nanoparticles.

The curable composition (first curable composition) further contains, in addition to silver nanoparticles, a fluorine-free curable component, an inorganic filler and/or a fluorine-containing component, since wet coating is easy. It is preferable to include.

(Fluorine-free curable component)
The fluorine-free curable component may be either a thermosetting resin or a photocurable resin, but a photocurable resin is preferred from the viewpoint of productivity. The photocurable resin (photocurable resin precursor component) may be a compound that can be cured or crosslinked with active energy rays such as ultraviolet rays or electron beams to form a resin.

Fluorine-free photocurable components include monomers, oligomers (or resins, especially low molecular weight resins).

Examples of monomers include monofunctional monomers [(meth)acrylic monomers such as (meth)acrylate, isobornyl (meth)acrylate, and adamantyl (meth)acrylate; vinyl-based monomers such as vinylpyrrolidone; monomers], bifunctional monomers [ethylene glycol di(meth)acrylate, propylene glycol di(meth)acrylate, butanediol di(meth)acrylate, neopentyl glycol di(meth)acrylate, hexanediol di(meth)acrylate, Alkylene glycol di(meth)acrylates such as meth)acrylate; (poly)oxyalkylene glycol di(meth)acrylate such as diethylene glycol di(meth)acrylate, dipropylene glycol di(meth)acrylate, polyoxytetramethylene glycol di(meth)acrylate ) acrylate; di(meth)acrylate having a bridged cyclic hydrocarbon group such as tricyclodecane dimethanol di(meth)acrylate, adamantane di(meth)acrylate], trifunctional or higher polyfunctional monomer [glycerintri (meth)acrylate, trimethylolpropane tri(meth)acrylate, trimethylolethane tri(meth)acrylate, tetramethylolmethane tri(meth)acrylate, pentaerythritol tri(meth)acrylate, tris(2-hydroxyethyl)isocyanurate tri (meth)acrylate, tetramethylolmethanetetra(meth)acrylate, ditrimethylolpropanetetra(meth)acrylate, pentaerythritol tetra(meth)acrylate, dipentaerythritol penta(meth)acrylate, dipentaerythritol hexa(meth)acrylate, etc. Examples include tri- to hexa-functional monomers. Among these, polyfunctional (meth)acrylates having at least two (meth)acryloyl groups in the molecule are widely used.

As the oligomer or resin, for example, (meth)acrylate of bisphenol A-alkylene oxide adduct, epoxy (meth)acrylate [polyfunctional epoxy (meth)acrylate having two or more (meth)acryloyl groups], polyester (meth)acrylate ) acrylate [polyfunctional polyester (meth)acrylate having two or more (meth)acryloyl groups], urethane (meth)acrylate [polyfunctional urethane (meth)acrylate having two or more (meth)acryloyl groups], silicone Examples include (meth)acrylate [polyfunctional silicone (meth)acrylate having two or more (meth)acryloyl groups] and (meth)acrylic polymers having polymerizable groups.

These fluorine-free photocurable components can be used alone or in combination of two or more. Among these, from the viewpoint of mechanical properties of the antireflection layer, polyfunctional monomers having two or more functionalities may be used, and polyfunctional monomers having three or more functionalities are preferred, and monomers having 3 to 6 functionalities may be used. More preferred are polyfunctional (meth)acrylates having 3 to 6 (meth)acryloyl groups, such as pentaerythritol tetra(meth)acrylate.

The fluorine-free photocurable component preferably contains 50% by mass or more, more preferably 80% by mass or more of a bifunctional or more polyfunctional monomer (particularly a 3-6 functional monomer), More preferably, it contains 90% by mass or more. The fluorine-free photocurable component may be only a polyfunctional monomer having two or more functionalities.

The proportion of silver nanoparticles is, for example, 0.1 to 100 parts by weight, preferably 1 to 80 parts by weight, more preferably 3 to 50 parts by weight, and more preferably 5 parts by weight, based on 100 parts by weight of the fluorine-free curable component. ~30 parts by weight, most preferably 10-20 parts by weight. If the proportion of silver nanoparticles is too small, there is a risk that the antibacterial properties will be reduced, and if the proportion of silver nanoparticles is too large, there is a possibility that the mechanical properties of the antireflection layer will be reduced.

(Inorganic filler and/or fluorine-containing component)
As the inorganic filler, an inorganic filler with a low refractive index is preferable. Examples of the low refractive index inorganic filler include metal compound particles such as metal oxide particles, metal nitride particles, metal sulfide particles, and metal halide particles. Examples of the metal of the metal compound include Mg, Ca, B, and Si.

These inorganic fillers can be used alone or in combination of two or more. Among these fillers, silica is preferred, and hollow silica is particularly preferred since it can suppress an increase in haze and improve transparency. The hollow silica may be hollow silica described in JP-A-2001-233611, JP-A-2003-192994, and the like.

The number average particle diameter of the inorganic filler (particularly hollow silica) is 100 nm or less, preferably 80 nm or less (for example, 10 to 80 nm), and more preferably about 20 to 70 nm.

The surface of the inorganic filler may be modified with a coupling agent (titanium coupling agent, silane coupling agent).

The fluorine-containing component includes a metal fluoride such as magnesium fluoride, a fluorine-containing photocurable component, and the like. Among these, fluorine-containing photocurable components are commonly used.

The fluorine-containing photocurable component may be a fluoride of a monomer or oligomer, which is a fluorine-free photocurable component exemplified in the section of the antireflection layer. Examples of fluorine-containing photocurable components include fluorinated alkyl (meth)acrylates [such as perfluorooctylethyl (meth)acrylate and trifluoroethyl (meth)acrylate], fluorinated (poly)oxyalkylene glycol di( meth)acrylate [e.g., fluoroethylene glycol di(meth)acrylate, fluoropolyethylene glycol di(meth)acrylate, fluoropropylene glycol di(meth)acrylate, etc.], fluorine-containing epoxy (meth)acrylate, fluorine-containing urethane (meth)acrylate For example,

These fluorine-containing photocurable components can be used alone or in combination of two or more.

Among these, fluoropolyether compounds having a (meth)acryloyl group and fluorine-containing urethane (meth)acrylates are preferred, and fluorine- and ester-containing urethane (meth)acrylates are particularly preferred.

The curable composition may be adjusted to have a low refractive index by containing at least one of an inorganic filler and a fluorine-containing component. Preferably, it includes combinations of ingredients.

When an inorganic filler and a fluorine-containing component are combined, the proportion of the fluorine-containing component may be 0.1 part by mass or more, for example 0.1 to 100 parts by mass, based on 100 parts by mass of the inorganic filler (especially hollow silica). The amount is 100 parts by weight, preferably 1 to 50 parts by weight, more preferably 2 to 30 parts by weight, more preferably 3 to 10 parts by weight, and most preferably 4 to 7 parts by weight. If the proportion of the fluorine-containing component is too small, there is a risk that the antireflection properties will decrease.

The total amount of the inorganic filler and the fluorine-containing component may be 10% by mass or more in the antireflection layer, for example, 10 to 99% by mass, preferably 30 to 98% by mass, more preferably 50 to 97% by mass, and more preferably is 70-95% by weight, most preferably 80-93% by weight. If the total amount is too small, there is a risk that the antireflection properties will deteriorate.

The total amount of the inorganic filler and fluorine-containing component is, for example, 10 to 5000 parts by mass, preferably 100 to 3000 parts by mass, more preferably 300 to 2000 parts by mass, and more preferably 500 to 1500 parts by weight, most preferably 800 to 1200 parts by weight. If the total amount is too small, there is a risk that the antireflection properties will be reduced, and if it is too large, there is a risk that the mechanical properties of the antireflection layer will be reduced.

(hardening agent)
The curable composition may further contain a curing agent depending on the type of fluorine-free curable component. For example, the thermosetting component may contain a curing agent such as amines and polyvalent carboxylic acids, and the photocuring component may contain a photopolymerization initiator. Examples of the photopolymerization initiator include conventional components such as acetophenones, propiophenones, benzyls, benzoins, benzophenones, thioxanthones, and acylphosphine oxides.

The proportion of the curing agent such as a photopolymerization initiator is, for example, 0.1 to 20 parts by weight, preferably 0.5 to 10 parts by weight, more preferably 1 to 5 parts by weight, per 100 parts by weight of the fluorine-free curable component. Part by mass.

The curable composition may further contain a curing accelerator. In particular, the photocurable component may contain a photocuring accelerator, for example, tertiary amines (dialkylaminobenzoic acid ester, etc.), a phosphine photopolymerization accelerator, and the like.

(other ingredients)
The curable composition may further contain other components in addition to the fluorine-free curable component, the inorganic filler, and/or the fluorine-containing component. Other ingredients include conventional additives, such as silane coupling agents (for example, silane coupling agents with thiol groups, etc.), leveling agents, stabilizers (antioxidants, ultraviolet absorbers, etc.), and surfactants. , water-soluble polymers, fillers other than the above-mentioned inorganic fillers, crosslinking agents, colorants, flame retardants, lubricants, waxes, preservatives, viscosity modifiers, thickeners, antifoaming agents, and the like.

The proportion of other components is, for example, 0.01 to 100 parts by weight, preferably 0.1 to 10 parts by weight, and more preferably 0.5 to 5 parts by weight, based on 100 parts by weight of the fluorine-free curable component. be.

[Middle layer]
In the laminate (optical laminate) of the present disclosure, an intermediate layer is interposed between the antireflection layer and the base layer. By interposing the antireflection layer between the base material layer and the intermediate layer, a laminate having antibacterial and antireflection properties can be obtained.

The thickness (average thickness) of the intermediate layer is, for example, 1 to 20 μm, preferably 1.5 to 10 μm, more preferably 2 to 8 μm, and more preferably 4 to 7 μm.

In the present disclosure, the average thickness of the intermediate layer can be determined by measuring arbitrary 10 locations using an optical film thickness meter and calculating the average value.

The intermediate layer may be a functional layer. Examples of the functional layer include a hard coat layer, an antiglare layer, a polarizing layer, a refractive index adjusting layer, and an adhesive layer. Among these, a hard coat layer is preferred since it is easy to form an antireflection layer by wet coating.

The intermediate layer (particularly the hard coat layer) is formed of a cured product of a curable composition (second curable composition) containing a curable component (hardenable component for intermediate layer).

(curable component)
The curable component may be either a thermosetting component or a photocurable component, but a photocurable component is preferred from the viewpoint of productivity and the like. Examples of the photocurable component include the photocurable components exemplified in the section of the antireflection layer. The photocurable components can be used alone or in combination of two or more.

Among the photocurable components, polyfunctional monomers having two or more functionalities are preferable, and polyfunctional monomers having five or more functionalities (for example, dipentaerythritol penta(meth)acrylate, dipentaerythritol hexa(meth)acrylate, dipentaerythritol hexa(meth) A combination with a 5- to 6-functional monomer (such as acrylate) is particularly preferred.

The proportion of the curable component for the intermediate layer may be 10% by mass or more in the intermediate layer, for example 10 to 90% by mass, preferably 20 to 80% by mass, more preferably 30 to 70% by mass, more preferably It is 40 to 60% by mass.

(Surface conditioning agent)
The curable composition for forming the intermediate layer preferably contains a surface conditioner in order to improve wettability with the antireflection layer. When the intermediate layer contains a surface conditioner, the antireflection layer can be easily formed by wet coating, and the antireflection layer can be tightly adhered onto the intermediate layer.

The surface conditioner may be a conventional leveling agent as long as it has the ability to lower surface tension. Examples of conventional leveling agents include silicone leveling agents, fluorine leveling agents, acetylene glycol leveling agents, and acrylic leveling agents. These leveling agents can be used alone or in combination of two or more. Among these, fluorine-based leveling agents and/or (meth)acrylic-based leveling agents are preferred from the viewpoint of improving the wettability (recoatability) of the antireflection layer.

The fluorine-based leveling agent may be any leveling agent having a fluoroaliphatic hydrocarbon skeleton. Examples of the fluoroaliphatic hydrocarbon skeleton include fluoroC _1-10 alkanes such as fluoromethane, fluoroethane, fluoropropane, fluoroisopropane, fluorobutane, fluoroisobutane, fluoro t-butane, fluoropentane, and fluorohexane. Can be mentioned. These fluoroaliphatic hydrocarbon skeletons may have at least some hydrogen atoms substituted with fluorine atoms, but perfluoroaliphatic hydrocarbon skeletons in which all hydrogen atoms are substituted with fluorine atoms are preferred.

Furthermore, the fluoroaliphatic hydrocarbon skeleton may form a polyfluoroalkylene ether skeleton, which is a repeating unit via an ether bond. The fluoroaliphatic hydrocarbon group as a repeating unit may be at least one selected from the group consisting of fluoroC _1-4 alkylene groups such as fluoromethylene, fluoroethylene, fluoropropylene, and fluoroisopropylene. These fluoroaliphatic hydrocarbon groups may be the same or a combination of multiple types. The repeating number (degree of polymerization) of the fluoroalkylene ether units may be, for example, about 10 to 3,000, preferably about 30 to 1,000, and more preferably about 50 to 500.

As the fluorine leveling agent, commercially available fluorine leveling agents can be used. Examples of commercially available fluorine-based leveling agents include the Optool series leveling agents ("DSX" and "DAC-HP") manufactured by Daikin Industries, Ltd., and the Surflon series leveling agents ("DSX" and "DAC-HP") manufactured by AGC Seimi Chemical Co., Ltd. S-242'', ``S-243'', ``S-420'', ``S-611'', ``S-651'', ``S-386'', etc.), BYK series leveling agent manufactured by BYK Chemie Japan Co., Ltd. "BYK-340", etc.), Algin Chemie's AC series leveling agent ("AC 110a", "AC 100a", etc.), DIC Corporation's Megafac series leveling agent ("Megafac F-114", "Megafuck F-410", "Megafuck F-444", "Megafuck EXP TP-2066", "Megafuck F-430", "Megafuck F-472SF", "Megafuck F-477", " Megafuck F-552", "Megafuck F-553", "Megafuck F-554", "Megafuck F-555", "Megafuck R-94", "Megafuck RS-72-K", " Megafuck RS-75", "Megafuck F-556", "Megafuck EXP TF-1367", "Megafuck EXP TF-1437", "Megafuck F-558", "Megafuck EXP TF-1537", etc. ), leveling agents of the FC series manufactured by Sumitomo 3M Ltd. (“FC-4430”, “FC-4432”, etc.), leveling agents of the Ftergent series manufactured by Neos Co., Ltd. (“Ftergent 100”, “Ftergent 100C”) ", "Ftergent 110", "Ftergent 150", "Ftergent 150CH", "Ftergent AK", "Ftergent 501", "Ftergent 250", "Ftergent 251", "Ftergent 222F ", "Ftergent 208G", "Ftergent 300", "Ftergent 310", "Ftergent 400SW", etc.), PF series leveling agent manufactured by Kitamura Kagaku Sangyo Co., Ltd. ("PF-136A", "PF- 156A”, “PF-151N”, “PF-636”, “PF-6320”, “PF-656”, “PF-6520”, “PF-651”, “PF-652”, “PF-3320” etc.) are examples.

The (meth)acrylic leveling agent may be any leveling agent as long as it has a (meth)acrylic skeleton. Examples of the (meth)acrylic skeleton include homopolymers or copolymers of (meth)acrylic esters. Examples of (meth)acrylic esters include methyl (meth)acrylate, ethyl (meth)acrylate, butyl (meth)acrylate, t-butyl (meth)acrylate, isobutyl (meth)acrylate, and (meth)acrylate. ) alkyl (meth)acrylates such as hexyl acrylate, octyl (meth)acrylate, and 2-ethylhexyl (meth)acrylate; diethylene glycol (meth)acrylate, dipropylene glycol (meth)acrylate, polyoxytetramethylene glycol (meth)acrylate; ) (poly)oxyalkylene glycol (meth)acrylate such as acrylate; polyester (meth)acrylate, and the like. These (meth)acrylic esters can be used alone or in combination of two or more. Among these, a combination of an alkyl (meth)acrylate such as C _1-10 alkyl (meth)acrylate and (poly)oxyalkylene glycol (meth)acrylate is preferred.

As the (meth)acrylic leveling agent, a commercially available (meth)acrylic leveling agent can be used. Commercially available (meth)acrylic leveling agents include BYK series leveling agents manufactured by BYK Chemie Japan Co., Ltd. ("BYK-350", "BYK-354", "BYK-355", "BYK-356", BYK-358N, BYK-361N, BYK-381, BYK-392, BYK-394, BYK-399, BYK-3440, BYK-3441, etc.), Kusumoto Leveling agents of the Disparon series manufactured by Kasei Co., Ltd. ("Disparon 1970", "Disparon 230", "Disparon 230HF", "Disparon LF-1980", "Disparon LF-1980", "Disparon LF-1982", "Disparon") LF-1983'', ``Disparon LF-1984'', ``Disparon LF-1985'', ``Disparon UVX-35'', ``Disparon UVX-36'', etc.).

Among these, (meth)acrylic leveling agents are particularly preferred since they have excellent wettability with the antireflection layer.

The proportion of the surface conditioner is, for example, 1 to 500 parts by weight, preferably 10 to 300 parts by weight, more preferably 20 to 200 parts by weight, and more preferably 30 to 150 parts by weight, based on 100 parts by weight of the curable resin for the intermediate layer. parts by weight, most preferably from 50 to 100 parts by weight. If the proportion of the surface conditioner is too small, the wettability with the antireflection layer may be reduced, and if it is too large, the mechanical properties of the intermediate layer may be degraded.

(hardening agent and other ingredients)
The curable composition for forming the intermediate layer may also further contain the curing agent and other components (components other than the surface conditioner) exemplified in the section of the antireflection layer. Preferred embodiments and ratios are also the same as those for the antireflection layer.

[Base material layer]
The base material layer (light-transmissive base material layer or transparent base material layer) may be formed of a transparent material. The transparent material can be selected depending on the purpose, and may be an inorganic material such as glass or an organic material. Examples of the inorganic material include glass, quartz, magnesium fluoride, and calcium fluoride. Examples of the organic material include cellulose ester, polyester, polyamide, polyimide, polycarbonate, and (meth)acrylic polymer.

Among these, organic materials (transparent organic materials) are commonly used from the viewpoint of strength and moldability, and cellulose ester, polyester, and polycarbonate are preferred.

Examples of the cellulose ester include cellulose acetate such as cellulose triacetate (TAC), cellulose acetate _C3-4 acylate such as cellulose acetate propionate, and cellulose acetate butyrate.

Examples of the polyester include polyalkylene arylates such as polyethylene terephthalate (PET) and polyethylene naphthalate (PEN).

Examples of the polycarbonate include bisphenol type polycarbonates such as bisphenol A type polycarbonate.

Among these, cellulose acetate such as TAC and polyester such as PET are preferred, and cellulose acetate is particularly preferred, in view of their excellent balance of mechanical properties, transparency, optical isotropy, and the like.

The proportion of the transparent material (especially transparent organic material) in the base material layer may be 50% by mass or more (for example, 50 to 100% by mass), preferably 80% by mass or more (for example, 80 to 99% by mass), and Preferably it is 90% by mass or more, more preferably 95% by mass or more.

The base layer may also contain other components exemplified in the section of the antireflection layer. Preferred embodiments and ratios are also the same as those for the antireflection layer.

The base layer may be a uniaxially or biaxially stretched film, but may also be an unstretched film because it has low birefringence and excellent optical isotropy.

The base material layer may be surface-treated (for example, corona discharge treatment, flame treatment, plasma treatment, ozone or ultraviolet irradiation treatment, etc.), and may have an easily adhesive layer.

The thickness (average thickness) of the base material layer is, for example, 5 to 2000 μm, preferably 15 to 1000 μm, more preferably 20 to 500 μm, and even more preferably 30 to 100 μm.

[Characteristics of laminate]
The laminate of the present disclosure has excellent antireflection properties and a neutral color tone with suppressed yellowing.

In the laminate of the present disclosure, the absolute value of the chromaticity (reflection hue) b ^* of the reflected light is, for example, 5 or less, preferably 3 or less (for example, 0.05 to 3), and more preferably 2 or less (for example, 0 .1 to 2), more preferably 1 or less (for example, 0.2 to 1), and most preferably 0.5 or less (for example, 0.3 to 0.5). If the chromaticity b ^* of the reflected light exceeds 5, the yellowish or bluish tinge will increase, making it appear dull, and there is a risk that transparency will decrease and a neutral hue may not be maintained.

In the laminate of the present disclosure, the absolute value of the chromaticity (reflection hue) a ^* of the reflected light is, for example, 10 or less, preferably 8 or less (for example, 0.1 to 8), more preferably 5 or less (for example, 0 .3 to 5), more preferably 4 or less (eg 0.5 to 4), most preferably 3 or less (eg 1 to 3). If the chromaticity a ^* of the reflected light exceeds 10, the reddish or greenish color will increase, making it look dull, and there is a risk that transparency will decrease and a neutral hue may not be maintained.

In the laminate of the present disclosure, the absolute value of the chromaticity (transmitted hue) b ^* of transmitted light is, for example, 5 or less, preferably 4 or less (for example, 0.05 to 4), and more preferably 3 or less (for example, 0 .1 to 3), more preferably 2 or less (for example, 0.2 to 2), and most preferably 1.5 or less (for example, 0.3 to 1.5). If the chromaticity b ^* of the transmitted light exceeds 5, the yellowish or bluish tinge will increase, making it look dull, and there is a risk that transparency will decrease and a neutral hue may not be maintained.

In the laminate of the present disclosure, the absolute value of the chromaticity (transmitted hue) a ^* of transmitted light is, for example, 3 or less, preferably 1 or less (for example, 0.02 to 1), and more preferably 0.5 or less ( For example, 0.03 to 0.5), more preferably 0.3 or less (for example, 0.05 to 0.3), and most preferably 0.2 or less (for example, 0.1 to 0.2). If the chromaticity a ^* of the transmitted light exceeds 3, the reddish or greenish color will increase and it will look dull, and there is a risk that the transparency will decrease and a neutral hue cannot be maintained.

In the laminate of the present disclosure, the lightness L ^* is, for example, 50 or less, preferably 40 or less (for example, 1 to 40), more preferably 30 or less (for example, 3 to 30), and more preferably 20 or less (for example, 5 to 20), most preferably 15 or less (eg 10-15). If the lightness L ^* is too large, there is a possibility that antireflection properties cannot be maintained.

In the laminate of the present disclosure, the luminous reflectance Y (%) may be, for example, 5% or less (for example, 0 to 5%), preferably 4% or less, more preferably 3% or less, and more preferably 2.5% or less, most preferably 2% or less. If the luminous reflectance Y is too large, there is a risk that the antireflection properties will be reduced.

Note that in the present disclosure, reflected hue b ^* , transmitted hue b ^* , reflected hue a ^* , transmitted hue a ^* , lightness L ^* , and luminous reflectance Y are measured using a spectrophotometer (Co., Ltd.) in accordance with JIS Z8781. ) Can be measured using Hitachi High-Tech Science "U-3010").

The transmission image clarity (IC) of the laminate of the present disclosure may be 80% or more, for example 80 to 99%, preferably 85 to 98%, and even Preferably it is 90-97%, more preferably 92-96%, and most preferably 93-95%. If the transmitted image clarity is too low, there is a risk that visibility will decrease.

In the present disclosure, the transmitted image clarity can be measured in accordance with JIS K7374, and more specifically, by the method described in the Examples described later.

The haze of the laminate of the present disclosure may be, for example, 10% or less, for example, 0.01 to 5%, preferably 0.03 to 3%, more preferably 0.05 to 1%, and more preferably 0. .1-0.8%, most preferably 0.15-0.5%. If the haze is too large, there is a risk that visibility will decrease.

Note that in the present disclosure, haze can be measured in accordance with JIS K7136, and more specifically, by a method described in Examples described later.

The laminate of the present disclosure has excellent transparency. The total light transmittance of the optical laminate may be, for example, 70% or more, for example, 70 to 100%, preferably 90 to 99%, more preferably 92 to 98%, and more preferably 93 to 97%. be. If the total light transmittance is too low, there is a risk that transparency will decrease.

Note that in the present disclosure, the total light transmittance can be measured in accordance with JIS K7361, and more specifically, by the method described in the Examples described later.

The thickness (average thickness) of the laminate of the present disclosure is, for example, 3 to 2000 μm, preferably 5 to 1000 μm, and more preferably 10 to 500 μm.

[Method for manufacturing laminate]
The method for manufacturing the laminate of the present disclosure may include an antireflection layer forming step of laminating an antireflection layer on the intermediate layer, but from the viewpoint of improving productivity, the antireflection layer forming step Preferably, a curable composition containing silver nanoparticles is wet coated.

The curable composition may contain a solvent. When the curable composition further contains a fluorine-free curable resin, an inorganic filler and/or a fluorine-containing compound in addition to silver nanoparticles, the solvent may be any solvent that can uniformly dissolve or disperse at least the solid content. Bye. Examples of such solvents include ketones (acetone, methyl ethyl ketone, methyl isobutyl ketone, cyclohexanone, etc.), ethers (dioxane, tetrahydrofuran, etc.), aliphatic hydrocarbons (hexane, etc.), alicyclic hydrocarbons ( cyclohexane, etc.), aromatic hydrocarbons (toluene, xylene, etc.), halogenated carbons (dichloromethane, dichloroethane, etc.), esters (methyl acetate, ethyl acetate, butyl acetate, etc.), water, alcohols (ethanol, isopropanol, butanol, cyclohexanol, etc.), cellosolves [methyl cellosolve, ethyl cellosolve, propylene glycol monomethyl ether (1-methoxy-2-propanol), etc.], cellosolve acetates, sulfoxides (dimethyl sulfoxide, etc.), amides (dimethylformamide, dimethylacetamide, etc.). Further, the solvent may be a mixed solvent. Among these solvents, aliphatic ketones such as methyl ethyl ketone and methyl isobutyl ketone, alcohols such as isopropanol, and cellosolves such as propylene glycol monomethyl ether are preferred; A combination of two or more selected from the group (for example, a combination of aliphatic ketones and alcohols, a combination of aliphatic ketones and cellosolves, a combination of aliphatic ketones, alcohols and cellosolves) Particularly preferred.

The concentration of the solute (silver nanoparticles, fluorine-free curable resin, inorganic filler and/or fluorine-containing compound, and other additives) in the curable composition is selected within a range that does not impair castability, coating properties, etc. For example, the amount is 0.1 to 30% by weight, preferably 0.3 to 20% by weight, more preferably 0.5 to 10% by weight, and most preferably 1 to 5% by weight.

As a coating method, conventional methods such as a roll coater, air knife coater, blade coater, rod coater, reverse coater, bar coater, comma coater, dip/squeeze coater, die coater, gravure coater, microgravure coater, and silk screen coater can be used. method, dip method, spray method, spinner method, etc. Among these methods, the bar coater method and the gravure coater method are commonly used. Note that, if necessary, the coating liquid may be applied multiple times.

After the curable composition is cast or applied, it may be dried to evaporate the solvent. Drying may be carried out naturally, but depending on the boiling point of the solvent, it may be carried out at a temperature of, for example, 30 to 200°C, preferably 50 to 150°C, more preferably 80 to 120°C.

When the fluorine-free curable resin is a photocurable resin, the obtained laminate is cured by irradiation with light to obtain an antireflection layer. Light irradiation can be selected depending on the type of photocurable resin, etc., and typically ultraviolet rays, electron beams, etc. can be used. A general-purpose light source is usually an ultraviolet irradiation device.

As a light source, for example, in the case of ultraviolet light, a deep UV lamp, a low-pressure mercury lamp, a high-pressure mercury lamp, an ultra-high-pressure mercury lamp, a halogen lamp, a laser light source (a light source such as a helium-cadmium laser or an excimer laser), etc. can be used. The amount of irradiation light (irradiation energy as an integrated amount of light) varies depending on the thickness of the coating film, and is, for example, 10 to 10,000 mJ/cm ² , preferably 20 to 5,000 mJ/cm ² , and more preferably 30 to 3,000 mJ/cm ² . Light irradiation may be performed in an inert gas atmosphere, if necessary.

The method for manufacturing a laminate of the present disclosure may further include an intermediate layer forming step of laminating an intermediate layer on the base layer. In the intermediate layer forming step, a conventional method can be used to laminate the intermediate layer, and a method can be used in which a coating liquid in which the composition for forming the intermediate layer is dissolved or dispersed in a solvent is applied and dried. When the composition contains a curable resin, it can be cured after drying in the same manner as the antireflection layer. The coating method, including preferred embodiments, is the same as the antireflection layer forming step.

As the solvent, the solvent used in the antireflection layer forming step can be used. Among the above solvents, aliphatic ketones such as methyl ethyl ketone are preferred. The drying temperature is, for example, 30 to 200°C, preferably 50 to 120°C, more preferably 60 to 100°C.

The concentration of the solute (resin component, surface conditioner, etc.) in the composition for forming the intermediate layer can be selected from a range of about 1 to 90% by mass without impairing flowability or coating properties, for example, about 5% by mass. ~80% by weight, preferably 10~70% by weight, more preferably 20~60% by weight, and even more preferably 30~50% by weight.

The present invention will be explained in more detail below based on Examples, but the present invention is not limited by these Examples. Details of the raw materials and films used in the Examples and Comparative Examples and the preparation method of the coating liquid are as follows, and the optical laminates obtained in the Examples and Comparative Examples were evaluated by the following methods.

[material]
Hard coat liquid: "FC-3201" manufactured by Nippon Kako Toyo Co., Ltd., solid content 46% by mass
Acrylic leveling agent: “BYK399” manufactured by BYK
Anti-reflection coating liquid: "ELCOM P-5063" manufactured by JGC Catalysts & Chemicals Co., Ltd., solid content 3% by mass
Multifunctional acrylate: Pentaerythritol tri- and tetraacrylate, “PETRA” manufactured by Daicel Ornex Co., Ltd.
Fluorine-containing curable compound solution: “KY-1203” manufactured by Shin-Etsu Chemical Co., Ltd., solid content 20% by mass
Silver nano ink: "Picosil DNS-0163I" manufactured by Daicel Corporation.

[film]
Cellulose triacetate (TAC) film: "FujiTac TG60UL" manufactured by Fuji Film Co., Ltd., thickness 60 μm.

[Thickness of hard coat layer and antireflection layer]
Using an optical film thickness meter, measurements were taken at ten arbitrary locations on each laminate sample, and the average value was calculated.

[Haze]
Measure the haze of each laminate sample using a haze meter (NDH-5000W manufactured by Nippon Denshoku Co., Ltd.) in accordance with JIS K7136, with the antireflection layer surface facing the receiver side. did.

[Total light transmittance]
The total light transmittance of each laminate sample was measured in accordance with JIS K7361 using a haze meter ("NDH5000W" manufactured by Nippon Denshoku Industries, Ltd.).

[Transmission image clarity (IC)]
The transmission image clarity of each laminate sample was measured using a mapping measuring device ("ICM-1T" manufactured by Suga Test Instruments Co., Ltd.) in accordance with JIS K7374. Among the optical combs of the mapping measuring device, the transmitted image clarity was measured using an optical comb with a width of 0.5 mm.

[Transparent hue (a ^* b ^* )]
In accordance with JIS Z8781, the transmitted hue of each laminate sample was measured using a spectrophotometer (“U-3010” manufactured by Hitachi High-Tech Science Co., Ltd.).

[Reflection hue (L ^* a ^* b ^* ) and luminous reflectance (Y)]
The reflective hue and luminous reflectance of each laminate sample were measured using a spectrophotometer (“U-3900H” manufactured by Hitachi High-Tech Science Co., Ltd.) in accordance with JIS Z8722. For each laminate sample, the opposite side of the anti-reflection layer was attached to a commercially available black acrylic plate with optical glue to minimize the influence of reflection from the back side, and measurements were taken.

[Antibacterial]
The antibacterial activity values of Staphylococcus aureus and Escherichia coli were measured based on JIS Z2801:2012. As a result of antibacterial property measurement on the surface of the antireflection layer of each laminate sample, samples in which the antibacterial activity value of the antibacterial-treated product was 2.0 or more relative to the unprocessed product were considered to have antibacterial properties.

Reference example 1
(Preparation of clear hard coat liquid)
A clear hard coat liquid was prepared by mixing 100 parts by weight of the hard coat liquid, 50 parts by weight of methyl ethyl ketone, and 40 parts by weight of an acrylic leveling agent.

(Applying clear hard coat liquid)
The obtained clear hard coat liquid was cast onto a TAC film using a wire bar (#16), and then left in an oven at 80°C for 1 minute to evaporate the solvent and form a hard coat with a thickness of approximately 6 μm. formed a layer. The hard coat layer was cured with ultraviolet light by irradiating the hard coat layer with ultraviolet light for about 5 seconds using a high-pressure mercury lamp to obtain a hard coat film.

(Preparation of non-antibacterial anti-reflection coating liquid)
100 parts by mass of antireflection coating liquid, 24.72 parts by mass of methyl isobutyl ketone, 6.18 parts by mass of isopropanol, 1.50 parts by mass of polyfunctional acrylate, 0.82 parts by mass of fluorine-containing curable compound solution, 0.02 parts by mass. A non-antibacterial anti-reflective coating solution was prepared by mixing.

(Coating of non-antibacterial anti-reflection coating liquid)
The obtained antibacterial antireflective coating solution was cast onto the hard coat layer of the hard coat film, and then left in an oven at 80°C for 1 minute to evaporate the solvent and form a non-antibacterial reflective coating with a thickness of about 100 nm. A prevention layer was formed. The hard coat layer was irradiated with ultraviolet rays for about 5 seconds using a high-pressure mercury lamp to cure the coat layer with ultraviolet rays to obtain a laminate (silver content: 0% by mass).

Example 1
(Preparation of antibacterial antireflection coating liquid)
100 parts by mass of antireflection coating liquid, 25.03 parts by mass of methyl isobutyl ketone, 6.26 parts by mass of isopropanol, 1.50 parts by mass of polyfunctional acrylate, 0.82 parts by mass of fluorine-containing curable compound solution, 0.02 parts by mass of silver nano ink. Parts by mass were mixed to prepare an antibacterial antireflection coating liquid.

(Application of antibacterial anti-reflection coating liquid)
The obtained antibacterial antireflection coating liquid was cast onto the hard coat layer of the hard coat film obtained in the same manner as in Reference Example 1, and then left in an oven at 80°C for 1 minute, and the solvent was evaporated to form an antibacterial antireflection layer with a thickness of about 100 nm. The hard coat layer was irradiated with ultraviolet rays for about 5 seconds using a high-pressure mercury lamp to cure the coat layer with ultraviolet rays to obtain a laminate (silver content: 0.3% by mass).

Example 2
(Preparation of antibacterial antireflection coating liquid)
100 parts by mass of antireflection coating liquid, 25.73 parts by mass of methyl isobutyl ketone, 6.43 parts by mass of isopropanol, 1.50 parts by mass of polyfunctional acrylate, 0.82 parts by mass of fluorine-containing curable compound solution, 0.07 parts by mass of silver nano ink. Parts by mass were mixed to prepare an antibacterial antireflection coating liquid.

(Application of antibacterial anti-reflection coating liquid)
The obtained antibacterial antireflection coating liquid was cast onto the hard coat layer of the hard coat film obtained in the same manner as in Reference Example 1, and then left in an oven at 80°C for 1 minute, and the solvent was evaporated to form an antibacterial antireflection layer with a thickness of about 100 nm. The hard coat layer was irradiated with ultraviolet rays for about 5 seconds using a high-pressure mercury lamp to cure the coat layer with ultraviolet rays to obtain a laminate (silver content: 1% by mass).

Example 3
(Preparation of antibacterial antireflection coating liquid)
100 parts by mass of antireflection coating liquid, 27.75 parts by mass of methyl isobutyl ketone, 6.94 parts by mass of isopropanol, 1.50 parts by mass of polyfunctional acrylate, 0.82 parts by mass of fluorine-containing curable compound solution, 0.21 parts by mass of silver nano ink. Parts by mass were mixed to prepare an antibacterial antireflection coating liquid.

(Application of antibacterial anti-reflection coating liquid)
The obtained antibacterial antireflection coating liquid was cast onto the hard coat layer of the hard coat film obtained in the same manner as in Reference Example 1, and then left in an oven at 80°C for 1 minute, and the solvent was evaporated to form an antibacterial antireflection layer with a thickness of about 100 nm. The hard coat layer was irradiated with ultraviolet rays for about 5 seconds using a high-pressure mercury lamp to cure the coat layer with ultraviolet rays to obtain a laminate (silver content: 3% by mass).

Table 1 shows the results of evaluating the optical properties of the laminates obtained in Reference Examples and Examples.

Furthermore, as a result of evaluating the antibacterial properties of the laminates obtained in the examples, all the laminates had antibacterial properties. Therefore, as is clear from the results in Table 1, the laminates obtained in Examples had antibacterial properties and, like Reference Example 1 which did not contain silver, had excellent transparency and suppressed yellowing. It had a neutral color.

The laminate of the present disclosure can be used in applications requiring antireflection properties, such as building materials, automobile window glass, and displays for display devices. Among them, on the surface of display devices such as liquid crystal displays (LCDs), cathode tube displays, organic or inorganic electroluminescent (EL) displays, field emission displays (FEDs), surface electric field displays (SEDs), and rear-projection television displays. It can be suitably used as an anti-reflection film, especially for applications that require high-definition images, such as game devices, smartphones, personal computers (PCs) (tablet PCs, notebook or laptop PCs, desktop PCs). It is particularly suitable for computer pointing devices such as PCs (PCs, etc.), computer pointing devices such as pen tablets, and display devices such as televisions.

Claims (12)

A laminate comprising a base layer, an intermediate layer laminated on at least one surface of the base layer, and an antireflection layer laminated on the intermediate layer and containing silver nanoparticles. The laminate according to claim 1, wherein the antireflection layer is formed of a cured product of a curable composition containing silver nanoparticles. The laminate according to claim 2, wherein the curable composition further contains a fluorine-free curable component, an inorganic filler and/or a fluorine-containing component. The curable composition further includes a fluorine-free curable component, an inorganic filler, and a fluorine-containing component, and the fluorine-free curable component is a polyfunctional (meth) having 3 to 6 (meth)acryloyl groups. The laminate according to claim 3, wherein the laminate is an acrylate, the inorganic filler is hollow silica, and the fluorine-containing component is a fluorine-containing curable component. The laminate according to any one of claims 1 to 4, wherein the intermediate layer is formed of a cured product of a curable composition containing a curable component and a (meth)acrylic leveling agent. The laminate according to any one of claims 1 to 5, wherein the base layer contains a transparent organic material. The laminate according to claim 6, wherein the transparent organic material comprises polyester or cellulose ester. The laminate according to any one of claims 1 to 7, wherein the absolute value of the chromaticity b ^* of the reflected light is 5 or less. The laminate according to any one of claims 1 to 8, wherein the antireflection layer is a wet coating layer. The method for producing a laminate according to any one of claims 1 to 9, comprising an antireflection layer forming step of laminating an antireflection layer on the intermediate layer. The manufacturing method according to claim 10, wherein in the antireflection layer forming step, a curable composition containing silver nanoparticles is wet coated. A display device comprising the laminate according to any one of claims 1 to 9.