KR102441912B1 - Optical laminate, polarizing plate, and display apparatus - Google Patents

Abstract

It is excellent in durability, rainbow_pattern|erythema is suppressed, visibility is high, and the optical laminated body in which thickness reduction is possible, and the polarizing plate and display apparatus using this are provided. The optical laminated body 1 provides the primer layer 3 and the glare-proof layer 4 which has an uneven|corrugated shape on the surface in this order on at least one surface of the transparent base material 2. The transparent base material 2 contains polyethylene terephthalate, and in-plane retardation is 600 nm or less, Furthermore, thickness direction retardation is 3000 nm or more.

Description

Optical laminate, polarizing plate, and display device {OPTICAL LAMINATE, POLARIZING PLATE, AND DISPLAY APPARATUS}

The present invention relates to an optical laminate suitable for an anti-glare film, and to a polarizing plate and a display device using the same.

Optical laminates, such as an optical laminated body, an antireflection film, and an anti-glare film, are used for display members, such as a liquid crystal display panel and a touch panel. As a transparent substrate constituting the optical laminate, a cellulose ester-based film such as triacetyl cellulose having excellent transparency and optical isotropy has been widely used, but the cellulose ester-based film has insufficient durability, particularly moisture resistance and heat resistance There are flaws. Then, instead of a cellulose ester-type film, using a polyethylene terephthalate (PET) film as a transparent base material is examined variously. PET film has the advantage of being excellent in transparency, moisture resistance, heat resistance, and mechanical strength, and being inexpensive.

However, since polyethylene terephthalate has an aromatic ring in its molecular structure, birefringence occurs in the plane of the PET film, and when an optical laminate using the PET film as a transparent substrate is laminated on the polarizing film, color unevenness like a rainbow (hereinafter referred to as "rainbow spots") occurs.

As a technique for canceling|resolving the rainbow spots which generate|occur|produces when PET is used for a transparent base material, there exists a thing described in Unexamined-Japanese-Patent 5556926, for example. In Unexamined-Japanese-Patent No. 5556926, when in-plane retardation (Re) uses the polyester base material 3000 nm or more, when it uses for a display apparatus, the rainbow_pattern|erythema is improved.

With recent display device thickness reduction and weight reduction, thickness reduction is calculated|required also for an optical laminated body, and thin film formation of the transparent base material used for an optical laminated body is aimed at. However, when the in-plane retardation of a PET film is made high as described in Unexamined-Japanese-Patent 5556926 in order to suppress the rainbow_pattern|erythema which generate|occur|produces when a PET film is used, the thickness of a PET film will also inevitably become thick. That is, when a PET film of high retardation is used for a transparent base material, thickness reduction becomes difficult.

Therefore, this invention is excellent in durability, rainbow_pattern|erythema is suppressed, visibility is high, and an object of this invention is to provide the optical laminated body in which thickness reduction is possible, and the polarizing plate and display apparatus using this.

The optical laminate according to the present invention contains polyethylene terephthalate and has an in-plane retardation of 600 nm or less and a thickness direction retardation of 3000 nm or more on at least one side of a transparent substrate, a primer layer, and an uneven shape on the surface The anti-glare layer was installed in this order.

Moreover, the polarizing plate which concerns on this invention is formed by laminating|stacking a polarizing base on the transparent base material which comprises the said optical laminated body, It is characterized by the above-mentioned.

Moreover, the display device which concerns on this invention is provided with the said optical laminated body, It is characterized by the above-mentioned.

ADVANTAGE OF THE INVENTION According to this invention, it is excellent in durability, a rainbow_pattern|erythema and interference fringe are suppressed, visibility is high, and can provide the optical laminated body in which thickness reduction is possible, and the polarizing plate and display apparatus using this.

These and other objects, features, aspects, and effects of the present invention will become more apparent from the following detailed description in conjunction with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS It is sectional drawing which shows typically an example of the optical laminated body which concerns on embodiment.
2 : is sectional drawing which shows typically another example of the optical laminated body which concerns on embodiment.

BRIEF DESCRIPTION OF THE DRAWINGS It is a schematic sectional drawing of the optical laminated body which concerns on embodiment.

The optical laminate 1 laminates|stacks the primer layer 3 and the glare-proof layer 4 on one side of the transparent base material 2 in this order.

(transparent material)

The transparent base material 2 is a film used as the base|substrate of the optical laminated body 1 . It is preferable that the thickness of the transparent base material 2 is 12-40 micrometers. When the thickness of the transparent base material 2 is less than 12 micrometers, the transparent base material 2 will become too thin, and the hardness of the glare-proof layer 4 and the intensity|strength of the optical laminated body 1 will fall. On the other hand, when the thickness of the transparent base material 2 exceeds 40 micrometers, since the optical laminated body 1 will become thick, it will become impossible to contribute to thickness reduction of the display member using the optical laminated body 1 .

As the transparent base material 2, in-plane retardation (Re) uses 600 nm or less, and thickness direction retardation (Rth) uses a polyethylene terephthalate film (PET film) of 3000 nm or more. When in-plane retardation and thickness direction retardation use PET film which exists in this range, when the optical laminated body 1 is superimposed on a polarizing plate, or the rainbow at the time of providing a polarizer on the optical laminated body 1 Non-uniformity can be suppressed and thin film formation of the transparent base material 2 can be implement|achieved further. When in-plane retardation exceeds 600 nm, since the thickness of the transparent base material 2 becomes thicker than 40 micrometers mentioned above, it is unpreferable. Moreover, when thickness direction retardation is less than 3000 nm, since it leads to the hardness fall of the glare-proof layer 4 when the optical laminated body 1 is comprised, it is unpreferable. Although the upper limit of the thickness direction retardation of the transparent base material 2 is not specifically limited, It is preferable to set it as 8000 nm or less.

Moreover, since PET film is excellent in low moisture permeability (water vapor barrier property), transparency, heat resistance, and mechanical strength, durability of the optical laminated body 1 can be improved by using it as the transparent base material 2 . Moreover, since a PET film is cheap, it is advantageous also in terms of manufacturing cost. Since the polyvinyl alcohol (PVA) film used for the polarizing plate has high hygroscopicity and expands by absorbing moisture to change its dimensions, it is common to attach a protective film on both sides to protect it from moisture. Since the PET film with water vapor barrier property (low moisture permeability) is used as the transparent base material 2 for the optical laminated body 1 which concerns on this embodiment, it is especially preferable as a protective film of a polarizing plate.

In addition, in order to improve adhesiveness with the primer layer 3 and the anti-glare layer 4 to the transparent base material 2, you may give a surface modification process. Examples of the surface modification treatment include alkali treatment, corona treatment, plasma treatment, sputtering treatment, application of a surfactant or silane coupling agent, and Si vapor deposition.

(primer layer)

The primer layer 3 has a function as an easily bonding layer which improves the adhesiveness of the glare-proof layer 4 with respect to the transparent base material 2 . The primer layer 3 is formed by, for example, coating and curing a composition for forming a primer layer containing at least an active energy ray-curable resin on the surface of the transparent substrate 2 . It is preferable that the thickness of the primer layer 3 shall be 40-120 nm.

(Anti-glare layer)

The anti-glare layer 4 is a layer which has a fine uneven|corrugated shape on the surface, and mainly provides anti-glare property to the optical laminated body 1 . The anti-glare layer 4 can be formed by hardening the composition for anti-glare layer formation containing active energy ray-curable resin and microparticles|fine-particles on the surface of the primer layer 3, for example. It is preferable that the thickness of the glare-proof layer 4 is 1-20 micrometers. When the thickness of the anti-glare layer 4 is less than 1 µm, the hardness of the anti-glare layer 4 is insufficient. On the other hand, since the thickness of the optical laminated body 1 will become thick when the thickness of the glare-proof layer 4 exceeds 20 micrometers, it will become impossible to contribute to thickness reduction of the display member using the optical laminated body 1 .

The active energy ray-curable resin used for the primer layer 3 and the anti-glare layer 4 is a resin that is polymerized and cured by irradiation with active energy rays such as ionizing radiation or ultraviolet rays, for example, monofunctional, bifunctional or A trifunctional or higher (meth)acrylate monomer can be used. In addition, in this specification, "(meth)acrylate" is a generic name of both acrylate and methacrylate, and "(meth)acryloyl" is a generic name of both acryloyl and methacryloyl. .

Examples of the resin material hardened by irradiation with ionizing radiation include radically polymerizable functional groups such as acryloyl group, methacryloyl group, acryloyloxy group, and methacryloyloxy group, epoxy group, vinyl ether group, oxetane group, etc. Monomers, oligomers, and prepolymers having a cationically polymerizable functional group may be used alone or in combination. As the monomer, methyl acrylate, methyl methacrylate, methoxy polyethylene methacrylate, cyclohexyl methacrylate, phenoxyethyl methacrylate, ethylene glycol dimethacrylate, dipentaerythritol hexaacrylate, trimethylolpropane tri Methacrylate, pentaerythritol triacrylate, etc. can be illustrated. Examples of the oligomer and prepolymer include acrylate compounds such as polyester acrylate, polyurethane acrylate, polyfunctional urethane acrylate, epoxy acrylate, polyether acrylate, alkyd acrylate, melamine acrylate and silicone acrylate, unsaturated polyester Epoxy compounds such as tetramethylene glycol diglycidyl ether, propylene glycol diglycidyl ether, neopentyl glycol diglycidyl ether, bisphenol A diglycidyl ether and various alicyclic epoxies, 3-ethyl-3 -Hydroxymethyloxetane, 1,4-bis{[(3-ethyl-3-oxetanyl)methoxy]methyl}benzene, di[1-ethyl(3-oxetanyl)]methyl ether, etc. A cetane compound can be illustrated.

The above-mentioned resin material can be hardened by irradiation of an ultraviolet-ray on condition of addition of a photoinitiator. Examples of the photopolymerization initiator include radical polymerization initiators such as acetophenone-based, benzophenone-based, thioxanthone-based, benzoin and benzoinmethyl ether, aromatic diazonium salts, aromatic sulfonium salts, aromatic iodonium salts, and metallocene compounds. Cationic polymerization initiators may be used alone or in combination.

The microparticles|fine-particles contained in the glare-proof layer 4 are added in order to form a fine concavo-convex structure on the surface and express anti-glare property, and various inorganic microparticles|fine-particles and organic microparticles|fine-particles (filler) can be used. However, microparticles|fine-particles are not necessarily required, and microparticles|fine-particles may be abbreviate|omitted as long as the fine concavo-convex shape required for expression of anti-glare property can be formed on the surface of the anti-glare layer 4 .

As the fine particles added to the anti-glare layer 4 , when inorganic fine particles are used, it is preferable that they are inorganic nanoparticles having an average particle diameter of 10 to 200 nm. It is preferable that the addition amount of an inorganic fine particle is 0.1 to 5.0 %.

As the inorganic fine particles, for example, swelling clay can be used. The swellable clay may have a cation exchange ability and may be swelled by introducing a solvent between the layers of the swellable clay, and may be a natural product or a synthetic product (including substituents and derivatives). Moreover, a mixture of a natural product and a synthetic|combination may be sufficient. Examples of the swelling clay include mica, synthetic mica, vermiculite, montmorillonite, iron montmorillonite, weidellite, saponite, hectorite, stevensite, nontronite, margadiite, islarite, kanemite, layered titanium. acid, smectite, synthetic smectite, and the like. These swellable clays may be used individually by 1 type, and may be used in mixture of plurality. Moreover, you may use colloidal silica, alumina, and zinc oxide individually or in mixture as an inorganic fine particle. In addition to the above-described swelling clay, one or more types may be used in combination with colloidal silica, alumina, and zinc oxide.

As the inorganic fine particles, layered organoclay is more preferable. In the present invention, the layered organoclay refers to one in which organic onium ions are introduced between the layers of the swellable clay. The organic onium ion is not limited as long as it can be organicated using the cation exchange property of the swellable clay. As the inorganic fine particles, for example, synthetic smectite (layered organoclay mineral) can be used. Synthetic smectite functions as a thickener for increasing the viscosity of the composition for forming an antiglare layer. Addition of synthetic smectite as a thickener suppresses sedimentation of resin particles and inorganic fine particles, and contributes to formation of an uneven structure on the surface of the anti-glare layer.

When organic fine particles (filler) are used as fine particles added to the anti-glare layer 4, acrylic resin, polystyrene resin, styrene-(meth)acrylic acid ester copolymer, polyethylene resin, epoxy resin, silicone resin, polyvinylidene fluoride, Resin particles made of a translucent resin material such as polyfluoroethylene-based resin can be used. In order to adjust a refractive index or dispersion|distribution of a resin particle, you may mix and use two or more types of resin particles from which a material (refractive index) differs. The resin particles (filler) aggregate in the base resin (binder resin) to form a fine concavo-convex structure on the surface of the anti-glare layer. By forming a random aggregation structure in the anti-glare layer without blending the resin particles, an uneven structure necessary for anti-glare expression can be provided. Easier to adjust

In addition, you may add a solvent suitably to the composition for primer layer formation or the composition for glare-proof layer formation. Examples of the solvent include dibutyl ether, dimethoxymethane, dimethoxyethane, diethoxyethane, propylene oxide, 1,4-dioxane, 1,3-dioxolane, 1,3,5-trioxane, tetrahydrofuran , ethers such as anisole and phenetol, polyethylene glycol methyl ether, acetone, methyl ethyl ketone, diethyl ketone, dipropyl ketone, diisobutyl ketone, methyl isobutyl ketone, cyclopentanone, cyclohexanone, and Ketones such as methylcyclohexanone, and esters such as ethyl formate, propyl formate, n-pentyl formate, methyl acetate, ethyl acetate, methyl propionate, ethyl propionate, n-pentyl acetate, and γ-butyrolactone, and methyl Cellosolves, such as a cellosolve, a cellosolve, a butyl cellosolve, and a cellosolve acetate, are mentioned. You may use these individually or in combination of 2 or more types.

Moreover, you may add additives, such as an antifouling agent, a surface preparation agent, a leveling agent, a refractive index regulator, a photosensitizer, and an electrically-conductive material, to the composition for primer layer formation or the composition for glare-proof layer formation as needed.

The optical laminate 1 according to the present embodiment is a roll-to-roll, at least one surface of the transparent substrate 2, the coating liquid of the composition for forming a primer layer described above is applied by a wet coating method, and to the coating film After curing the active energy ray-curable resin by irradiating active energy rays such as electron beams or ultraviolet rays, the coating solution of the composition for forming an antiglare layer described above is applied on the primer layer 3 by a wet coating method, and electron beams are applied to the coating film It can form by irradiating active energy rays, such as an ultraviolet-ray, and hardening an active energy ray-curable resin. Examples of the wet coating method include a flow coating method, a spray coating method, a roll coating method, a gravure roll coating method, an air doctor coating method, a blade coating method, a wire doctor coating method, a knife coating method, a reverse coating method, a transformer roll coating method, Well-known methods, such as the micro gravure coating method, the kiss coating method, the cast coating method, the slot orifice coating method, the calender coating method, the die-coating method, are employable. In addition, when a coating film is hardened by ultraviolet irradiation, in the case of ultraviolet irradiation, a high pressure mercury lamp, a halogen lamp, a xenon lamp, a fusion lamp, etc. can be used. The amount of ultraviolet irradiation is usually about 100 to 800 mJ/cm ² .

In the optical laminated body 1 which concerns on this embodiment, since PET film is used as the transparent base material 2, compared with acetyl cellulose-type films, such as a triacetyl cellulose, the water vapor transmission rate is low, and it is excellent in water vapor barrier property. Moreover, since PET film is excellent also in heat resistance and mechanical strength, durability of the optical laminated body 1 can be improved by using it as the transparent base material 2 . Moreover, since a PET film has high transparency and is cheap, it is preferable as an optical laminated body used for an image display apparatus etc.

Generally, when the optical laminated body which used the PET film as the transparent base material 2 is used for an image display apparatus, it is easy to generate|occur|produce the rainbow_pattern|erythema resulting from the birefringence of PET itself. This rainbow nonuniformity becomes a factor which reduces the visibility of an image display apparatus. However, in the optical laminate 1 according to the present embodiment, by using a PET film having an in-plane retardation of 600 nm or less and a thickness direction retardation of 3000 nm or more as the transparent substrate 2, the occurrence of rainbow spots is reduced. can be suppressed Interference fringes resulting from a refractive index difference with the anti-glare layer 4 can be suppressed.

(Other variations)

In the optical laminate 1 according to the embodiment, at least one other functional layer 6 such as a refractive index adjusting layer, an antistatic layer, or an antifouling layer is formed on the antiglare layer 4 having irregularities on the surface. do.

2 : is sectional drawing which shows the example of the optical laminated body 1 which further provided the low-refractive-index layer as the functional layer 6 on the glare-proof layer 4 . A low-refractive-index layer is a refractive index adjustment layer for reducing a reflectance by reducing the refractive index of a surface. The low refractive index layer is formed by applying a coating solution containing an ionizing radiation curable material such as a polyester acrylate-based monomer, an epoxy acrylate-based monomer, a urethane acrylate-based monomer, and a polyol acrylate-based monomer and a polymerization initiator, and the coating film is subjected to polymerization. It can be formed by hardening by In the low-refractive-index layer, as the low-refractive particles, low-refractive-index fine particles containing a low-refractive material such as LiF, MgF, 3NaF·AlF or AlF (all, refractive index 1.4), or Na ₃ AlF ₆ (crylite, refractive index 1.33) It may be dispersed. In addition, as the low-refractive-index microparticles|fine-particles, the particle|grains which have a space|gap inside a particle|grain can be used suitably. In the case of particles having voids inside the particles, since the portion of the voids can be said to be the refractive index of air (≈1), low refractive index particles having a very low refractive index can be obtained. Specifically, by using low-refractive-index silica particles having voids therein, the refractive index can be lowered.

The antistatic layer is an ionizing radiation curable material such as a polyester acrylate-based monomer, an epoxy acrylate-based monomer, a urethane acrylate-based monomer, and a polyol acrylate-based monomer, a polymerization initiator, and an antistatic agent. It can be formed by hardening|curing by superposition|polymerization. As the antistatic agent, for example, metal oxide fine particles such as tin oxide (ATO) doped with antimony, indium oxide (ITO) doped with tin, polymeric conductive compositions, quaternary ammonium salts, and the like can be used. An antistatic layer may be provided in the outermost surface of an optical laminated body, and may be provided between a glare-proof layer and a translucent base.

An antifouling layer is provided on the outermost surface of an optical laminated body, and improves antifouling property by providing water repellency and/or oil repellency to an optical laminated body. The antifouling layer can be formed by dry coating or wet coating of silicon oxide, fluorine-containing silane compound, fluoroalkylsilazane, fluoroalkylsilane, fluorine-containing silicon-based compound, perfluoropolyether group-containing silane coupling agent, or the like. have.

Instead of the above-described low-refractive-index layer, antistatic layer, and antifouling layer, or in addition to the low refractive index layer, antistatic layer, and antifouling layer, at least one of an infrared absorption layer, an ultraviolet absorption layer, a color correction layer, etc. may be formed.

Moreover, in the optical laminated body 1 which concerns on this embodiment, it is preferable that the random aggregation structure is formed in the glare-proof layer 4 .

The random agglomeration structure means that a first phase containing a relatively large amount of a resin component (binder component) and a second phase containing a relatively large amount of an inorganic component are intertwined three-dimensionally, and the second phase is fine particles (resin particles). It refers to a structure ubiquitous around By forming the random aggregation structure in the anti-glare layer 4, since fine unevenness|corrugation can be reduced, anti-glare property and the black tone at the time of black display can be improved. A random aggregation structure can be formed by the method described in Unexamined-Japanese-Patent No. 5802043, for example.

In addition, even when a random aggregation structure is formed in the anti-glare layer 4, functional layers such as the low-refractive-index layer, antistatic layer, antifouling layer, infrared absorbing layer, ultraviolet absorbing layer, and color correction layer described above on the anti-glare layer 4 . In (6), at least one layer may be formed.

Moreover, you may comprise a polarizing plate using the optical laminated body 1 which concerns on this embodiment. Specifically, a polarizing film is formed by adsorbing and orienting an iodine or dye to a PVA film, and a polarizing plate can be configured by bonding the optical laminate 1 according to the present embodiment to both surfaces of this polarizing film as a protective film. . Alternatively, a polarizing plate is constituted by providing a polarizing layer on the other side (surface on which the anti-glare layer 4 is not provided) of the transparent substrate 2 of the optical laminate 1 shown in FIG. 1 by a known method. You can do it. In this case, you may bond the optical laminated body 1 or another protective film further on a polarizing layer. A polarizing layer can be formed by adsorb|sucking and orientating an iodine and dye to a PVA film, for example.

Further, the optical laminate 1 according to the present embodiment can be used in combination with a liquid crystal panel or the like to constitute a display device. As a structural example of a display device, what laminated|stacked the optical laminated body 1 which concerns on this embodiment in order from the observation side, a polarizing plate, a liquid crystal panel, a polarizing plate, and a backlight unit in this order is mentioned. In addition, a touch sensor may be further laminated to configure a touch sensor-equipped display device.

In addition, the optical laminated body 1 which concerns on this embodiment can be utilized as an optical laminated body used for display apparatuses, such as a smart phone, a tablet computer, and a notebook computer, and a display apparatus with a touch sensor (touch panel). As an optical laminated body, other than an optical laminated body, the above-mentioned polarizing plate, an antireflection film, an anti-glare film, etc. are mentioned. Specifically, the optical laminate 1 according to the present embodiment is a film provided on the outermost surface of a display panel such as a liquid crystal display device, or a film provided on the outermost surface of a touch panel of an on-cell system or an in-cell system. Or, in a touch panel assembled by a direct bonding method or an air gap method, it can be used as an intermediate film provided between the touch sensor and the display panel.

In addition, although the example which provided the primer layer 3 and the anti-glare layer 4 on one side of the transparent base material 2 was demonstrated in this embodiment, the primer layer 3 and anti-glare on both surfaces of the transparent base material 2 You may comprise the optical laminated body in which the layer 4 was provided.

[Example]

Hereinafter, examples in which the present invention is specifically implemented will be described. In addition, in the following examples and comparative examples, although the optical laminated body which formed the primer layer and the glare-proof layer on the transparent base material was produced, the optical laminated body which concerns on this invention is not limited only to the film of this three-layer structure .

<Composition for forming a primer layer>

The following materials were mixed to prepare a composition for forming a primer layer.

・Base resin

Product name: UF8001G (non-yellowing type oligourethane acrylate), Kyoeisha Chemical Co., Ltd. 0.85 parts by mass

・Polymerization initiator

Trade name: Irgacure (registered trademark) 184 (1-hydroxycyclohexylphenyl ketone), BASF 0.04 parts by mass

·solvent

17.46 parts by mass of methyl ethyl ketone (MEK)

11.64 parts by mass of polyethylene glycol monomethyl ether (PGME)

<Composition for forming an anti-glare layer>

The following materials were mixed to prepare compositions 1 to 4 for forming an anti-glare layer.

[Paint 1 for anti-glare layer formation]

Base resin: UV/EB curable resin light acrylate PE-3A (pentaerythritol triacrylate, manufactured by Kyoeisha Chemical Co., Ltd.), refractive index 1.52

91.7 parts by mass

・Resin particles (filler): polystyrene particles, average particle diameter 2.0 μm, refractive index 1.595

1.0 parts by mass

・Inorganic fine particles 1: 0.5 parts by mass of synthetic smectite

·Inorganic fine particles 2: alumina nanoparticles, average particle diameter 40 nm 2.0 parts by mass

-Photoinitiator: 4.8 mass parts of Irgacure 184 (made by BASF Japan)

In addition, as a solvent, the mixed solvent which mixed toluene and isopropyl alcohol in the ratio of 16:37 was used.

[Paint 2 for anti-glare layer formation]

Base resin: UV/EB curable resin light acrylate PE-3A (pentaerythritol triacrylate, manufactured by Kyoeisha Chemical Co., Ltd.), refractive index 1.52

91.7 parts by mass

・Resin particles (filler): styrene-methyl methacrylate copolymer particles, average particle diameter 2.0 μm, refractive index 1.515

1.0 parts by mass

・Inorganic fine particles 1: 0.5 parts by mass of synthetic smectite

·Inorganic fine particles 2: alumina nanoparticles, average particle diameter 40 nm 2.0 parts by mass

-Photoinitiator: 4.8 mass parts of Irgacure 184 (made by BASF Japan)

In addition, as a solvent, the mixed solvent which mixed toluene and isopropyl alcohol in the ratio of 16:37 was used.

[Paint 3 for forming anti-glare layer]

Base resin: UV/EB curable resin light acrylate PE-3A (pentaerythritol triacrylate, manufactured by Kyoeisha Chemical Co., Ltd.), refractive index 1.52

82.4 parts by mass

・Resin particles (filler): styrene-methyl methacrylate copolymer particles, average particle diameter 3.35 μm, refractive index 1.565

10.0 parts by mass

·Inorganic fine particles 1: 1.8 parts by mass of synthetic smectite

·Inorganic fine particles 2: Alumina nanoparticles, average particle diameter 40 nm 1.0 parts by mass

-Photoinitiator: 4.8 mass parts of Irgacure 184 (made by BASF Japan)

In addition, as a solvent, toluene was used.

[Paint 4 for forming anti-glare layer]

Base resin: UV/EB curable resin light acrylate PE-3A (pentaerythritol triacrylate, manufactured by Kyoeisha Chemical Co., Ltd.), refractive index 1.52

82.4 parts by mass

・Resin particles (filler): polystyrene particles, average particle diameter 3.5 μm, refractive index 1.595

10.0 parts by mass

・Inorganic fine particles 1: 1.8 parts by mass of synthetic smectite

·Inorganic fine particles 2: Alumina nanoparticles, average particle diameter 40 nm 1.0 parts by mass

-Photoinitiator: 4.8 mass parts of Irgacure 184 (made by BASF Japan)

In addition, as a solvent, toluene was used.

<Transparent substrate>

In Examples 1 to 7 and Comparative Examples 1, 2 and 4, a polyethylene terephthalate (PET) film having the thickness shown in Table 1, in-plane retardation (Re), and thickness-direction retardation (Rth) as a transparent substrate was used. was used. In Comparative Example 3, a triacetyl cellulose (TAC) film having a thickness shown in Table 1 was used as the transparent substrate.

<Production of optical laminates>

(Examples 1 to 4, Comparative Examples 1, 2 and 4)

On one side of the transparent substrate, the coating solution of the composition for forming a primer layer described above is applied by a bar coating method and dried, and then the coating film is cured by irradiating ultraviolet rays at an irradiation dose of 200 mJ/m 2 using a metal halide lamp to cure the primer. layer was formed. In addition, the coating liquid coating amount of the composition for primer layer formation was adjusted so that the thickness of a cured film might be set to 40 nm.

Then, on the formed primer layer, the coating solution of the above-described composition for forming an anti-glare layer was applied by a bar coating method and dried, and then the coating film was cured by irradiating ultraviolet rays at an irradiation dose of 200 mJ/m 2 using a metal halide lamp. , an anti-glare layer was formed. In addition, the coating liquid coating amount of the composition 1 for glare-proof layer formation was adjusted so that the thickness of a cured film might become the value shown in Table 1.

(Example 5)

An optical laminate was produced by the method similar to Example 1 except having used the coating liquid 2 for glare-proof layer formation instead of the coating liquid 1 for glare-proof layer formation in Example 1.

(Example 6)

An optical laminate was produced by the method similar to Example 1 except having used the coating liquid 3 for glare-proof layer formation instead of the coating liquid 1 for glare-proof layer formation in Example 1.

(Example 7)

An optical laminate was produced by the method similar to Example 1 except having used the coating liquid 4 for glare-proof layer formation instead of the coating liquid 1 for glare-proof layer formation in Example 1.

(Comparative Example 3)

On one side of the transparent substrate, without forming a primer layer, the coating solution of the above-described composition 1 for forming an anti-glare layer was applied by a bar coating method and dried, and then ultraviolet rays at an irradiation dose of 200 mJ/m 2 using a metal halide lamp It irradiated, the coating film was hardened, and the glare-proof layer was formed. In addition, the coating liquid coating amount of the composition for glare-proof layer formation was adjusted so that the thickness of a cured film might become the value shown in Table 1.

About the optical laminated body obtained by Examples 1-7 and Comparative Examples 1-4, haze, transmitted image clarity, pencil hardness, the grade of rainbow_pattern|erythema, and water vapor transmission rate were evaluated. The evaluation method and evaluation criteria are as follows.

<Heize>

The haze was measured according to JIS K7105 using a haze meter (NDH2000, manufactured by Nippon Denshoku Kogyo Co., Ltd.).

<Transparent Sharpness>

Transmitted image sharpness was measured with an optical comb width of 0.5 mm using an image quality measuring device (ICM-1T, manufactured by Suga Shikenki Co., Ltd.) in accordance with JIS K7105.

<Pencil hardness>

Based on JISK5600 (4.9N load), the pencil hardness of the hard-coat layer surface was measured using the pencil scratch tester (HA-301, Tester Sangyo Corporation). When the measured pencil hardness was 2H or more, it determined that surface hardness was sufficient.

<Rainbow Stains>

The optical laminated body according to each Example and each comparative example was superimposed on the surface of a display (manufactured by Sony Corporation, liquid crystal TV model number: KDL-46F5), and an image was displayed on the display. It observed visually, and the following reference|standard evaluated the grade of a rainbow_pattern|erythema.

(double-circle): A rainbow_pattern|erythema is not seen.

(circle): Although rainbow_pattern|erythema is seen slightly, it is fully suppressed.

(triangle|delta): A rainbow stain is seen.

x: Rainbow unevenness is seen remarkably.

<Water vapor permeability (water vapor permeability)>

About the optical laminated body which concerns on each Example and each comparative example, the water vapor transmission rate in the environment of a temperature of 40 degreeC and 90% RH of a relative humidity was measured based on JIS-Z208. When the measured water vapor transmission rate was 80 g/m 2 ·day or less, it was determined that the water vapor barrier property was sufficient.

The material and physical property value of the transparent base material used for the optical laminated body which concerns on Examples 1-7 and Comparative Examples 1-4, and the evaluation value of haze, transmitted image clarity, pencil hardness, the degree of rainbow_pattern|erythema, and water vapor transmission rate are collectively shown.

In the optical laminated body which concerns on Examples 1-7, rainbow_pattern|erythema was sufficiently suppressed so that the visibility of an image was not impaired. Moreover, the optical laminated body which concerns on Examples 1-7 was also excellent also in water vapor barrier property and surface hardness, and it was confirmed that it was excellent in durability.

On the other hand, in the optical laminated body which concerns on the comparative example 1, since thickness direction retardation used PET film of less than 3000 nm as a transparent base material, the surface hardness of the glare-proof layer fell.

In the optical laminated body which concerns on the comparative example 2, since in-plane retardation of PET film exceeded 600 nm, rainbow_pattern|erythema was not able to fully suppress.

The optical laminate according to Comparative Example 3 had low water vapor barrier properties because triacetyl cellulose was used for the transparent substrate.

In the optical laminate according to Comparative Example 4, since a PET film of high retardation (in-plane retardation and thickness-direction retardation of about 10000 nm) was used as a transparent substrate, rainbow spots were suppressed, but Examples 1 to 7 and In comparison, the transparent substrate became thick. Therefore, it was confirmed that the optical laminate according to Comparative Example 4 was not suitable for thickness reduction.

Thus, according to this invention, it was excellent in durability, rainbow_pattern|erythema was suppressed, visibility was high, and it was confirmed that the optical laminated body in which thickness reduction can be provided can be provided.

The optical laminated body which concerns on this invention can be used as an anti-glare film which suppresses projection of external light, In particular, it can use suitably for an image display apparatus as a base material of a polarizing plate, or a protective film of a polarizing plate.

As mentioned above, although this invention was demonstrated in detail, the above description is only an illustration of this invention in all points, and is not intended to limit the scope. It goes without saying that various improvements and modifications can be made without departing from the scope of the present invention.

Claims (7)

On at least one side of a transparent substrate containing polyethylene terephthalate, having an in-plane retardation of 600 nm or less and a thickness direction retardation of 3000 nm or more, a primer layer and an anti-glare layer having an uneven shape on the surface are installed in this order, ,
The anti-glare layer is a cured film of a coating solution containing a base resin, resin particles, synthetic smectite, and alumina nanoparticles,
The pencil hardness of the anti-glare layer is 2H or more,
haze is 0.9 to 3.5%,
An optical laminate having a transmitted image sharpness of 79 to 89%, measured with an optical comb width of 0.5 mm. According to claim 1,
The optical laminate, characterized in that the anti-glare layer comprises at least one anti-glare layer comprising a radiation curable resin. According to claim 1,
The optical laminated body further equipped with at least 1 layer of a refractive index adjusting layer, an antistatic layer, and an antifouling|stain-resistant layer. A polarizing plate in which a polarizing gas is laminated on the transparent substrate constituting the optical laminate according to any one of claims 1 to 3. A display device comprising the optical laminate according to any one of claims 1 to 3.

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