KR20220063183A - Polarizing plate and image display device having an adhesive layer - Google Patents

Abstract

[Problem] To provide a polarizing plate capable of suppressing light leakage from the end of the polarizing plate even when incorporated in a display device with a narrow bezel or a display device with a low bezel height.
[Solutions] A polarizing plate having a pressure-sensitive adhesive layer comprising a polarizing film, a first cured material layer, a first resin film, and an pressure-sensitive adhesive layer in this order,
The polarizing film and the first cured material layer are in direct contact with each other,
The first cured material layer and the first resin film are in direct contact with each other,
The first resin film and the pressure-sensitive adhesive layer are in direct contact,
The polarizing plate which has an adhesive layer whose absolute value of the difference of the average refractive index of a 1st hardened|cured material layer and the average refractive index of a 1st resin film is 0.03 or less.

Description

Polarizing plate and image display device having an adhesive layer

The present invention relates to a polarizing plate having a pressure-sensitive adhesive layer and an image display device including the polarizing plate.

A polarizing plate has the structure by which the protective film was laminated|stacked on the at least one surface of a polarizing film through an adhesive bond layer. A polarizing plate is generally incorporated in a display device through an adhesive layer (for example, patent document 1). In general, such a display device protects the outer periphery of the display device by providing a metal frame called a bezel in order to suppress an external shock.

Patent Document 1: Japanese Patent Laid-Open No. 2009-42383

In recent years, there is a tendency for display devices to be further slimmed down and to have a larger screen. In accordance with this trend, it has been proposed to enlarge the display screen even for a display device of the same size by narrowing the bezel width, lowering the bezel height, or omitting the bezel. However, if the width of the bezel is narrowed, when the height of the bezel is lowered, or when a polarizer is embedded in a display device when the bezel is omitted, the end of the polarizer built into the display device is exposed and the power of the display device is turned on. It turned out that the light emitted from a backlight or an organic light emitting element may leak from the edge part of a polarizing plate at this time.

The present invention includes the following inventions.

[1] A polarizing plate having a pressure-sensitive adhesive layer comprising a polarizing film, a first cured product layer, a first resin film, and an pressure-sensitive adhesive layer in this order,

The polarizing film and the first cured product layer are in direct contact with each other,

The first cured material layer and the first resin film are in direct contact,

The first resin film and the pressure-sensitive adhesive layer are in direct contact,

The polarizing plate which has an adhesive layer whose absolute value of the difference of the average refractive index of a 1st hardened|cured material layer and the average refractive index of a 1st resin film is 0.03 or less.

[2] The polarizing plate according to [1], wherein the first cured material layer is a cured product of an active energy ray-curable composition.

[3] The polarizing plate according to [1] or [2], wherein the refractive index of the first cured product layer is 1.55 or less.

[4] The polarizing plate according to any one of [1] to [3], wherein the first resin film includes a film formed of a thermoplastic resin.

[5] The polarizing plate according to any one of [1] to [4], wherein the first resin film has a thickness of 6 µm or more.

[6] The polarizing plate according to any one of [1] to [5], wherein the surface of the polarizing film other than the first cured material layer is provided with a second resin film with a second cured material layer interposed therebetween.

[7] An image display device comprising: an image display panel; and a polarizing plate having the pressure-sensitive adhesive layer according to any one of [1] to [6], which is disposed on the visual recognition side of the image display panel.

The polarizing plate of the present invention can suppress light leakage from the end of the polarizing plate even if it is incorporated in a display device with a narrow bezel width, a display device with a low bezel height, or a display device with a bezel omitted.

1 is a cross-sectional view showing a configuration that is one embodiment of the polarizing plate of the present invention.
Fig. 2 is a cross-sectional view showing a configuration that is one embodiment of the image display device of the present invention.
Fig. 3 is a cross-sectional view showing a method of confirming light leakage in the image display device of the present invention.

EMBODIMENT OF THE INVENTION Hereinafter, embodiment of this invention is described in detail. In addition, the scope of the present invention is not limited to the embodiments described herein, and various changes can be made without impairing the spirit of the present invention.

When the structure in one Embodiment of the polarizing plate of this invention is demonstrated based on FIG. 1, the polarizing plate 10 of this invention is the 1st hardened|cured material layer 2 on one side of the polarizing film 1, and The first resin films 3 are laminated in this order. Moreover, as the polarizing plate of this invention shows in FIG. 2, in the surface on the opposite side to the 1st hardened|cured material layer 2 of the polarizing film 1, through the 2nd hardened|cured material layer 4, 2nd resin You may have a structure with which the film 5 was provided. Moreover, it is good also as the display device 30 by laminating|stacking with the panel 7 through the adhesive layer 6 interposed.

Hereinafter, each structural component of the polarizing plate of this invention is demonstrated in detail.

[Polarizing plate having an adhesive layer]

The polarizing plate with an adhesive layer of this invention is equipped with the polarizing film 1, the 1st hardened|cured material layer 2, the 1st resin film 3, and the adhesive layer 6 in this order. The absolute value of the difference between the average refractive index of the 1st hardened|cured material layer 2, and the average refractive index of the 1st resin film 3 is 0.03 or less in the polarizing plate which has an adhesive layer of this invention. Moreover, the polarizing film 1 and the 1st hardened|cured material layer 2 are in direct contact, the 1st hardened|cured material layer 2 and the 1st resin film 3 are directly contacted, The 1st resin film 3 and the adhesive Layer 6 is in direct contact.

In addition, the average refractive index in this invention shows the average refractive index in wavelength 589nm.

In the polarizing plate having the pressure-sensitive adhesive layer of the present invention, the absolute value of the difference between the average refractive index n2 of the first cured material layer 2 and the average refractive index of the first resin film 3 is 0.03 or less, preferably 0.025 or less, More preferably, it is 0.02 or less, More preferably, it is 0.01 or less. When the difference between the average refractive index of the first cured material layer 2 and the refractive index of the first resin film 3 satisfies this range, when the polarizing plate is applied to a display device, light leakage from the end of the polarizing plate can be effectively suppressed .

The light leakage from the end of the polarizing plate in the present invention is described based on FIG. 3 , when the power of the display device 30 is turned on and the display device is viewed from an angle inclined by θ (°) in the cross-sectional direction from the front of the display device. At this time, the light emitted from the display device leaks from the end face of the polarizing plate, and the end face of the polarizing plate appears shiny. As θ is larger (for example, 15° to 90°), light leakage tends to be strongly visually recognized, and when θ exceeds 40° (especially when it exceeds 80°), light leakage is remarkably visually recognized. According to the polarizing plate having an adhesive layer of the present invention, even when the display device is viewed from an angle where θ is 30° to 90° (in particular, 40° to 90°, particularly 80° to 90°), light leakage of the polarizing plate is reduced. can be suppressed

<First cured material layer>

Although the 1st hardened|cured material layer 2 will not have a restriction|limiting in particular if the average refractive index difference with a 1st resin film becomes a predetermined range, Usually, it is a layer formed from a resin composition, and is a hardened|cured material layer of a resin composition. Specifically, as the 1st hardened|cured material layer 2, the layer formed from the adhesive composition (adhesive layer), the layer formed from the water-based adhesive composition, the layer formed from the active energy ray-curable adhesive composition, etc. are mentioned. Especially, since adjustment of an average refractive index is possible easily, it is preferable that it is a layer (hardened|cured material layer of an active energy ray hardening-type adhesive composition) formed from an active energy ray hardening-type adhesive composition.

An active energy ray-curable adhesive composition is a composition which receives irradiation of an active energy ray, and hardens|cures. For example, a cationically polymerizable active energy ray-curable adhesive composition containing a cationically polymerizable compound and a cationic polymerization initiator (hereinafter, sometimes referred to as a photocationically polymerizable curable adhesive composition), a radically polymerizable compound and a radical polymerization initiator. contains both a radical polymerizable active energy ray-curable adhesive composition (hereinafter, sometimes referred to as a photo-radically polymerizable curable adhesive composition), a cationically polymerizable compound and a radically polymerizable compound, and contains a cationic polymerization initiator and a radical The active energy ray hardening-type adhesive composition which mix|blended the polymerization initiator, and the electron beam hardening-type adhesive agent composition etc. which are hardened by irradiating an electron beam to the active energy ray hardening-type adhesive agent which do not contain an initiator are mentioned.

The cationic polymerizable compound refers to a compound or oligomer that is cured by a cationic polymerization reaction proceeding by irradiation or heating of active energy rays such as ultraviolet rays, visible light, electron beams, and X-rays, specifically, epoxy compounds, oxetane compounds, A vinyl compound etc. are mentioned. The active energy ray hardening-type adhesive composition may use 2 or more types of cationically polymerizable compounds.

An epoxy compound is a compound which has 1 or more (preferably 2 or more) epoxy groups in a molecule|numerator. As an epoxy compound, an alicyclic epoxy compound, an aromatic epoxy compound, an aliphatic epoxy compound, etc. are mentioned.

The alicyclic epoxy compound is a compound having one or more epoxy groups bonded to the alicyclic ring in the molecule, for example, 3,4-epoxycyclohexylmethyl 3,4-epoxycyclohexanecarboxylate, 3,4-epoxy-6 -Methylcyclohexylmethyl 3,4-epoxy-6-methylcyclohexanecarboxylate, ethylenebis(3,4-epoxycyclohexanecarboxylate), bis(3,4-epoxycyclohexylmethyl)adipate, bis (3,4-epoxy-6-methylcyclohexylmethyl) adipate, diethylene glycol bis (3,4-epoxycyclohexyl methyl ether), ethylene glycol bis (3,4-epoxycyclohexyl methyl ether), 2, 3,14,15-diepoxy-7,11,18,21-tetraoxatrispiro[5.2.2.5.2.2]henicosan, 3-(3,4-epoxycyclohexyl)-8,9-epoxy- 1,5-dioxaspiro[5.5]undecane, 4-vinylcyclohexenedioxide, limonene dioxide, bis(2,3-epoxycyclopentyl)ether, and dicyclopentadienedioxide are mentioned.

An aromatic epoxy compound is a compound which has an aromatic ring and an epoxy group in a molecule|numerator, Bisphenol-type epoxy compounds, such as diglycidyl ether of bisphenol A, diglycidyl ether of bisphenol F, and diglycidyl ether of bisphenol S, or its oligomers; novolak-type epoxy resins such as phenol novolac epoxy resins, cresol novolac epoxy resins, and hydroxybenzaldehyde phenol novolac epoxy resins; Polyfunctional epoxy compounds such as glycidyl ether of 2,2',4,4'-tetrahydroxydiphenylmethane and glycidyl ether of 2,2',4,4'-tetrahydroxybenzophenone ; and polyfunctional epoxy resins such as epoxidized polyvinyl phenol.

An aliphatic epoxy compound is a compound which has at least 1 oxirane ring (3-membered cyclic ether) couple|bonded with an aliphatic carbon atom in a molecule|numerator. For example, monofunctional epoxy compounds, such as butyl glycidyl ether and 2-ethylhexyl glycidyl ether; Bifunctional epoxy compounds such as 1,4-butanediol diglycidyl ether, 1,6-hexanediol diglycidyl ether, and neopentyl glycol diglycidyl ether; trifunctional or more trifunctional epoxy compounds such as trimethylolpropane triglycidyl ether and pentaerythritol tetraglycidyl ether; and an epoxy compound having one epoxy group directly bonded to an alicyclic ring and an oxirane ring bonded to an aliphatic carbon atom, such as 4-vinylcyclohexene dioxide and limonene dioxide.

An oxetane compound is a compound containing one or more oxetane rings (oxetanyl group) in a molecule|numerator. Specifically, for example, 3-ethyl-3-hydroxymethyloxetane (also called oxetane alcohol), 2-ethylhexyloxetane, 1,4-bis[{(3-ethyloxetan-3-yl) )methoxy}methyl]benzene (also called xylylenebisoxetane), 3-ethyl-3 [{(3-ethyloxetan-3-yl)methoxy}methyl]oxetane, 3-ethyl-3 -(phenoxymethyl)oxetane and 3-(cyclohexyloxy)methyl-3-ethyloxetane are mentioned. An oxetane compound may be used as a main component of a cationically polymerizable compound, and may be used together with an epoxy compound.

Examples of the vinyl compound include aliphatic or alicyclic vinyl ether compounds. For example, n-amyl vinyl ether, i-amyl vinyl ether, n-hexyl vinyl ether, n-octyl vinyl ether, 2-ethylhexyl vinyl ether, n-dodecyl vinyl ether, stearyl vinyl ether, oleyl vinyl ether, etc. vinyl ethers of alkyl or alkenyl alcohols having 5 to 20 carbon atoms; hydroxyl group-containing vinyl ethers such as 2-hydroxyethyl vinyl ether, 3-hydroxypropyl vinyl ether, and 4-hydroxybutyl vinyl ether; vinyl ethers of monoalcohols having an aliphatic ring or an aromatic ring, such as cyclohexyl vinyl ether, 2-methylcyclohexyl vinyl ether, cyclohexylmethyl vinyl ether, and benzyl vinyl ether; Glycerol monovinyl ether, 1,4-butanediol monovinyl ether, 1,4-butanediol divinyl ether, 1,6-hexanediol divinyl ether, neopentyl glycol divinyl ether, pentaerythritol divinyl ether, pentaerythritol Tetravinyl ether, trimethylolpropane divinyl ether, trimethylol propane trivinyl ether, 1,4-dihydroxycyclohexane monovinyl ether, 1,4-dihydroxycyclohexane divinyl ether, 1,4-dihydro mono-polyvinyl ethers of polyhydric alcohols such as hydroxymethylcyclohexane monovinyl ether and 1,4-dihydroxymethylcyclohexane divinyl ether; polyalkylene glycol mono to divinyl ethers such as diethylene glycol divinyl ether, triethylene glycol divinyl ether, and diethylene glycol monobutyl monovinyl ether; Other vinyl ethers, such as glycidyl vinyl ether and ethylene glycol vinyl ether methacrylate, are included.

It is preferable that a cationic polymerization initiator is a photocationic polymerization initiator. A photocationic polymerization initiator generate|occur|produces a cationic species or a Lewis acid by irradiation of an active energy ray, and starts the polymerization reaction of a cation-curable compound. Since a photocationic polymerization initiator acts catalytically with light, even if it mixes with a photocationic polymeric compound, it is excellent in storage stability and workability|operativity. As a photocationic polymerization initiator, onium salts, such as an aromatic iodonium salt and an aromatic sulfonium salt, an aromatic diazonium salt, an iron- arene complex, etc. are mentioned, for example. The active energy ray hardening-type adhesive composition may use 2 or more types of cationic polymerization initiators. Content of a cationic polymerization initiator is 0.5-10 mass parts normally with respect to 100 mass parts of cationically polymerizable compounds.

A radically polymerizable compound refers to the compound or oligomer which a radical polymerization reaction advances and hardens|cures by irradiation or heating of an active energy ray, The compound etc. which have an ethylenically unsaturated bond are specifically mentioned. Examples of the compound having an ethylenically unsaturated bond include a (meth)acrylic compound having one or more (meth)acryloyl groups in the molecule; and vinyl compounds such as styrene, styrenesulfonic acid, vinyl acetate, vinyl propionate, and N-vinyl-2-pyrrolidone. Here, the (meth)acryloyl group means that either an acryloyl group or a methacryloyl group may be sufficient, and "(meth)" at the time of calling (meth)acrylate etc. in addition is the same meaning.

An active energy ray hardening-type adhesive agent composition may use 2 or more types of radically polymerizable compounds.

It is preferable that a radical polymerization initiator is a photoradical polymerization initiator. A photoradical polymerization initiator starts the polymerization reaction of a radically polymerizable compound by irradiation of an active energy ray. Examples of the photoradical polymerization initiator include acetophenone-based initiators such as acetophenone and 3-methylacetophenone; benzophenone-based initiators such as benzophenone and 4-chlorobenzophenone; benzoin ether-based initiators such as benzoin propyl ether and benzoin ethyl ether; Thioxanthone type initiators, such as 4-isopropyl thioxanthone, etc. are mentioned. The active energy ray-curable adhesive composition may use 2 or more types of photoradical polymerization initiators.

The active energy ray-curable composition may contain various additives as needed. As an additive, a sensitizer, an ion trap agent, antioxidant, a chain transfer agent, a tackifier, a thermoplastic resin, a filler, a flow regulator, a plasticizer, an antifoamer, etc. are mentioned.

The 1st hardened|cured material layer 2 apply|coated active energy ray hardening-type adhesive composition on the polarizing film 1 or the 1st resin film 3, for example, The active energy ray apply|coated by irradiating an active energy ray. It can obtain by hardening a curable adhesive composition.

Well-known coating methods, such as a doctor blade, a wire bar, a die coater, a comma coater, and a gravure coater, can be used for coating of an active energy ray hardening adhesive composition.

The light source at the time of curing the active energy ray-curable adhesive composition is preferably a light source having a light emission distribution at a wavelength of 400 nm or less, low pressure mercury lamp, medium pressure mercury lamp, high pressure mercury lamp, ultra high pressure mercury lamp, chemical lamp, black light lamp, microwave Here, a mercury lamp, a metal halide lamp, etc. are mentioned.

Although the light irradiation intensity at the time of hardening an active energy ray hardening-type adhesive composition can be set suitably with an active energy ray hardening adhesive composition, the light irradiation intensity of the wavelength region effective for activation of a polymerization initiator is 0.1-1000 mW/cm<2> it is preferable When the light irradiation intensity at the time of curing of the active energy ray-curable adhesive composition is too small, the time required for the reaction to proceed sufficiently becomes long. The heat generated during polymerization of the composition may cause deterioration of the film to be adhered. Although the light irradiation time at the time of hardening of an active energy ray-curable adhesive composition is not specifically limited, It is preferable to set so that the accumulated light amount represented by the product of light irradiation intensity and light irradiation time may be 10-5000 mJ/cm<2>. When the amount of accumulated light is too small, generation of active species derived from the polymerization initiator is not sufficient, and there is a possibility that the obtained curing may be insufficient. In addition, when the amount of integrated light is too large, the irradiation time becomes very long, which is disadvantageous for improving productivity.

From the viewpoint of optical properties, the average refractive index of the first cured product layer 2 is preferably 1.59 or less, more preferably 1.55 or less, still more preferably 1.54 or less, and particularly preferably 1.51 or less. Moreover, it is preferable that it is 1.49 or more, and it is more preferable that it is 1.50 or more.

The average refractive index of the 1st hardened|cured material layer 2 can be adjusted by selecting suitably the kind, these content, etc. of the polymeric compound which an active energy ray hardening-type adhesive composition has. For example, when the active energy ray curing adhesive composition is a photocationically polymerizable curing adhesive composition, the refractive index of the compound itself, such as an alicyclic epoxy compound or an aromatic epoxy compound, is high, so that the average refractive index of the first cured material layer 2 is included. tends to rise.

As an active energy ray hardening-type adhesive composition which forms the 1st hardened|cured material layer 2, it is preferable that it is a photocationically polymerizable hardening-type adhesive composition or a photoradically polymerizable hardening-type adhesive composition.

Although there is no restriction|limiting in particular as for the thickness of the 1st hardened|cured material layer 2, It is preferable that it is 0.1 micrometer or more, It is more preferable that it is 0.5 micrometer or more, It is still more preferable that it is 1 micrometer or more, It is especially preferable that it is 2.1 micrometer or more. Moreover, it is preferable that it is 20 micrometers or less, It is more preferable that it is 10 micrometers or less, It is still more preferable that it is 5 micrometers or less.

<First Resin Film>

The first resin film 3 includes at least a film made of a thermoplastic resin. The 1st resin film 3 may be formed in one layer, and may be formed in two or more layers. The first resin film 3 may be, for example, a single resin film formed of a thermoplastic resin, or a laminated film in which a plurality of resin films formed of a thermoplastic resin are laminated, or cured resin on at least one surface of a resin film formed of a thermoplastic resin A layered film may be used.

When the first resin film 3 is formed of a plurality of layers, the average refractive index of the layer in direct contact with the first cured material layer among the plurality of layers in the first resin film, and the average refractive index of the first cured material layer It is good if the difference of 0.03 or less. For example, when the first resin film 3 is a film consisting of two layers of a cured resin layer and a resin film formed of a thermoplastic resin, if the layer in direct contact with the first cured material layer is a cured resin layer, the cured resin layer and the first The difference in refractive index of the cured material layer may be 0.03 or less, and if the first cured material layer and the resin film formed of the thermoplastic resin are in direct contact with each other, the refractive index difference between the layer formed of the thermoplastic resin and the first cured material layer may be 0.03 or less.

Specific examples of the film formed of the thermoplastic resin include polyolefin-based resins such as polyethylene, polypropylene, and polymethylpentene; Cyclic polyolefin-based resins having a cycloolefin or norbornene structure: fluorinated polyolefin-based resins such as polyvinyl fluoride, polyvinylidene fluoride, and polyethylene fluoride; polyester-based resins such as polyethylene naphthalate, polyethylene terephthalate, polybutylene terephthalate, and polyethylene terephthalate/isophthalate copolymer; polyamides such as nylon 6 and nylon 6,6; vinyl polymers such as polyvinyl chloride, vinyl chloride-vinyl acetate copolymer, ethylene-vinyl acetate copolymer, ethylene-vinyl alcohol copolymer, polyvinyl alcohol, and vinylon; Cellulose-based resins such as triacetyl cellulose, diacetyl cellulose, and cellophane; (meth)acrylic resins, such as polymethyl methacrylate, polyethyl methacrylate, polyethyl acrylate, and polybutyl acrylate; In addition, the resin film comprised from polystyrene, polycarbonate, polyarylate, polyimide, etc. is mentioned.

The resin film formed of a thermoplastic resin may be a film formed of the composition containing the said resin and an additive. As said additive, a ultraviolet absorber, antioxidant, surfactant, a plasticizer, a lubricant, an anti-blocking agent, etc. are mentioned.

The average refractive index of the resin film formed of a thermoplastic resin can be adjusted by the kind of resin, polymerization degree of resin, etc. Moreover, you may adjust by mix|blending an additive with resin.

It is preferable that it is a cellulose-type resin film, a (meth)acrylic-type resin film, or a cycloolefin-type resin film, and, as for the resin film formed from a thermoplastic resin, it is more preferable that it is a cycloolefin-type resin film.

When the first resin film 3 includes a cured resin layer, the cured resin layer is not particularly limited as long as the average refractive index difference is within a predetermined range, but is usually a layer formed of a resin composition, and is a cured product of the resin composition is the floor Specific examples thereof include a layer formed of an aqueous resin composition and a layer formed of an active energy ray-curable composition.

The aqueous resin composition is not particularly limited, but contains at least a resin component, and the resin component is dissolved or dispersed in water. Examples of the resin forming the water-based resin composition include polyvinyl alcohol-based resins, polyurethane-based resins, polyester-based resins, and acrylic resins having crosslinkable functional groups such as oxazoline groups. When the film formed of the thermoplastic resin is a cycloolefin-based resin film, it is preferable that the cured resin layer be formed of a polyurethane-based resin from the viewpoint of adhesion to the film.

A polyurethane-based resin is typically a reaction product of a polyol and a polyisocyanate. As the polyol component, a polyacrylic polyol obtained by polymerization of a (meth)acrylic acid ester and a hydroxyl group-containing monomer, a polyester polyol obtained by the reaction of a polybasic acid and a polyol, and a polyether polyol obtained by the reaction of a polybasic acid and a polyol It is preferably used.

In addition, polyurethane-type resin may have an acid structure. Examples of the acid structure include acid groups such as a carboxyl group (-COOH) and a sulfonic acid group (-SO3H). In addition, the acid structure may exist in a side chain in a polyurethane-type resin, and may exist in the terminal. In addition, one type of acid structure may be used and may be used combining two or more types by arbitrary ratios. As content of an acid structure, it is preferable that they are 10 mgKOH/g - 250 mgKOH/g or less as an acid value in a polyurethane.

A commercially available polyurethane resin may be used, and as a commercially available product, for example, "Adecarbon Titer" series manufactured by ADEKA, "Olester" series manufactured by Mitsui Chemicals, and "Bone" manufactured by Dainippon Ink Chemical Industries, Ltd. Dick series, "Hydran" series, Bayer's "Impranil" series, Kao's "Poise" series, Sanyo Kasei Kogyo's "Sanplen" series, Hodogaya Chemicals' "Aize" series Lux" series, Daiichi Kogyo Pharmaceutical's "Superflex" series, Zeneca's "NeoRez" series, Lubrizol's "Sancure" series, etc. can be used.

In addition, a polyurethane may be used individually by 1 type, and may be used combining two or more types by arbitrary ratios.

The aqueous resin composition may contain a crosslinking agent. As the crosslinking agent, those capable of reacting with the crosslinkable functional group of the polyurethane resin may be used without particular limitation. When a polyurethane resin has a carboxy group, the crosslinking agent containing an amino group, an oxazoline group, an epoxy group, a carbodiimide group, etc. is used.

The aqueous resin composition may contain a base component. As a base component, Inorganic bases, such as sodium hydroxide and potassium hydroxide; A primary amine compound, a secondary amine compound, a tertiary amine compound, a hydrazide compound, an imidazoline compound, etc. are mentioned. Especially, the compound which has a hydrazino group (-NHNH2 group) like a hydrazide compound can improve the mechanical strength of a polyurethane resin layer suitably, It is preferable. Examples of the hydrazide compound include carbodihydrazide, oxalic acid dihydrazide, isophthalic acid dihydrazide, terephthalic acid dihydrazide, glycolic acid dihydrazide, and polyacrylic acid dihydrazide.

The cured resin layer may be a film formed of a composition containing the resin and an additive. As said additive, a ultraviolet absorber, antioxidant, surfactant, a plasticizer, a lubricant, anti-blocking, an inorganic particle agent, organic microparticles|fine-particles, etc. are mentioned.

The average refractive index of a cured resin layer can be adjusted with the kind of resin, the polymerization degree of resin, the kind of crosslinking agent, etc. Moreover, you may adjust by mix|blending an additive with resin.

The thickness of the cured resin layer is usually 0.01 to 5 µm, preferably 0.03 to 2 µm, and more preferably 0.05 to 0.5 µm.

The 1st resin film 3 may have a retardation value and does not need to have a retardation value. In addition, the 1st resin film 3 may have a phase difference in plane, and may have a phase difference in the thickness direction. The in-plane retardation (R _e ) and the retardation (R _th ) in the thickness direction are defined by the following formulas (1) and (2).

R _th =[(n _x +n _y )/2-n _z ]×d (1)

R _e =(n _x -n _y )×d (2)

(wherein, n _x is the refractive index of the in-plane slow axis direction (x-axis direction) at a wavelength of 586 nm, and n _y is the in-plane fast axis direction (orthogonal to the x-axis in-plane) at a wavelength of 586 nm. is the refractive index in the y-axis direction), n _z is the refractive index in the thickness direction (z-axis direction perpendicular to the film plane) of the film at a wavelength of 586 nm, and d is the thickness of the film.)

The average refractive index of the first resin film 3 (a layer in direct contact with the first cured material layer when two or more layers are included) is preferably 1.44 to 1.57, more preferably 1.45 to 1.55 from the viewpoint of optical properties. It is preferable, it is more preferable that it is 1.48-1.54, It is especially preferable that it is 1.52-1.53.

The thickness of the first resin film 3 is preferably 6 µm or more, more preferably 12 µm or more, still more preferably 20 µm or more, particularly preferably from the ease of handling when laminating it on a polarizing film. is 40 µm or more, preferably 200 µm or less, more preferably 180 µm or less, still more preferably 150 µm or less, particularly preferably 100 µm or less. When the 1st resin film 3 is formed in multiple layers, the sum total should just be the said range.

<Polarizing film>

The polarizing film 1 is a film having a function of extracting linearly polarized light from incident natural light. As the polarizing film 1, the polyvinyl alcohol-type resin film made to contain a dichroic dye (preferably iodine), and the film which carried out adsorption orientation is mentioned. A film in which a dichroic dye is adsorbed and oriented to a polyvinyl alcohol-based resin film can be produced by a known method, and is usually a step of uniaxially stretching a polyvinyl alcohol-based resin film, and a polyvinyl alcohol-based resin film is applied to a dichroic dye It is manufactured through the process of adsorbing the dichroic dye by dyeing with , and the process of treating the polyvinyl alcohol-based resin film to which the dichroic dye has been adsorbed with an aqueous boric acid solution. Further, for example, a film in which a dichroic dye is adsorbed and orientated to a polyvinyl alcohol-based resin film can be obtained also by the method described in JP 2012-159778 A .

It is preferable that it is 3-30 micrometers, and, as for the thickness of the polarizing film 1, it is more preferable that it is 10-25 micrometers.

It is preferable that the value of the average refractive index of the polarizing film 1 is the same as the average refractive index of the 1st hardened|cured material layer 2, or the one larger than the value of the average refractive index of the 1st hardened|cured material layer 2 is preferable.

It is preferable that the value of the average refractive index of the polarizing film 1 is larger than the value of the average refractive index of the 1st resin film 3 .

<Second cured material layer>

The polarizing plate with an adhesive layer of this invention may be equipped with the 2nd hardened|cured material layer 4 in the surface on the opposite side to the 1st hardened|cured material layer 2 of the polarizing film 1. Although other layers may exist between the 2nd hardened|cured material layer 4 and the polarizing film 1, it is preferable that the 2nd hardened|cured material layer 4 and the polarizing film 1 are in direct contact.

The 2nd hardened|cured material layer 4 is a layer normally formed from a resin composition, and is a hardened|cured material layer of a resin composition. Specifically, the layer formed from the pressure-sensitive adhesive composition (adhesive layer), the layer formed from the water-based adhesive composition, the layer formed from the active energy ray-curable composition, etc. are mentioned.

The resin composition which forms the 2nd hardened|cured material layer 4 may be the same as the resin composition which forms the 1st hardened|cured material layer 2, and a different thing may be sufficient as it.

It is preferable that the 2nd hardened|cured material layer 4 is a layer formed from an active energy ray-curable composition.

<Second resin film>

It is preferable that the 2nd resin film 5 is a film excellent in transparency, mechanical strength, thermal stability, moisture shielding property, isotropy, etc. For example, polyester-type polymers, such as a polyethylene terephthalate and a polyethylene naphthalate; Cellulose polymers, such as a diacetyl cellulose and a triacetyl cellulose; acrylic polymers such as polymethyl methacrylate; styrenic polymers such as polystyrene and acrylonitrile-styrene copolymer (AS resin); A polycarbonate-type polymer is mentioned. In addition, polyethylene, polypropylene, polyolefin having a cyclo-based or norbornene structure; polyolefin-based polymers such as ethylene/propylene copolymers; amide-based polymers such as vinyl chloride-based polymers, nylon and aromatic polyamides; Imide polymer, sulfone polymer, polyether sulfone polymer, polyether ether ketone polymer, polyphenylene sulfide polymer, vinyl alcohol polymer, vinylidene chloride polymer, vinyl butyral polymer, arylate polymer, poly an oxymethylene-based polymer, an epoxy-based polymer, or a blend of the above polymers.

The same resin film may be sufficient as the 2nd resin film 5 and the 1st resin film 3, and different resin films may be sufficient as them.

It is preferable that the 2nd resin film 5 is a film with low water vapor transmission rate. The water vapor transmission rate of the second resin film 5 is preferably 800 g/(m 2 ·24 hours) or less, and more preferably 600 g/(m 2 ·24 hours) at a temperature of 40°C and a relative humidity of 90%. Hereinafter, more preferably, it is 400 g/(m 2 ·24 hours) or less, particularly preferably 200 g/(m 2 ·24 hours) or less, and particularly preferably 100 g/(m 2 ·24 hours) or less. If the moisture permeability of the second resin film 5 is less than or equal to the above value, the intrusion of moisture from the outside is prevented under high temperature and high humidity, and the movement of the dichroic dye (iodine) contained in the polarizing film 1 can be prevented from being accelerated. Therefore, deterioration of optical properties can be prevented more effectively.

Although the thickness in particular of the 2nd resin film 5 is not restrict|limited, Usually, it is 5-500 micrometers, Preferably it is 1-300 micrometers, More preferably, it is 5-200 micrometers, More preferably, it is 10-100 micrometers.

<Adhesive layer>

The adhesive layer 6 may be a layer formed from a well-known adhesive composition. As an adhesive composition, the adhesive composition which has an acrylic resin, a rubber-type resin, a urethane resin, silicone resin, polyvinyl ether-type resin etc. as a base polymer is mentioned, for example.

The pressure-sensitive adhesive composition may be an energy ray-curable pressure-sensitive adhesive composition or a thermosetting pressure-sensitive adhesive composition.

It is preferable that the adhesive composition which forms the adhesive layer 6 is an acrylic adhesive composition which used the acrylic resin excellent in transparency, adhesive force, rework property, weather resistance, heat resistance, etc. as a base polymer.

The pressure-sensitive adhesive layer 6 can be prepared by a method of applying the pressure-sensitive adhesive composition as an organic solvent solution to the first resin film 3 with a die coater, a gravure coater, or the like, and drying it. Moreover, it can provide also with the method of transcribe|transferring to the 1st resin film 3 the sheet-like adhesive composition formed on the plastic film (referred to as a separate film) to which the mold release process was given.

Although there is no restriction|limiting in particular as for the thickness of the adhesive layer 6, It is preferable to exist in the range of 2-40 micrometers, It is more preferable to exist in the range of 5-35 micrometers, It is more preferable to exist in the range of 10-30 micrometers.

It is preferable that the storage elastic modulus is 0.10-5.0 Mpa in 23-80 degreeC, and, as for the adhesive layer 6, it is more preferable that it is 0.15-1.0 Mpa. When the storage elastic modulus in 23-80 ° C. is 0.10 MPa or more, the liquid crystal display panel containing the polarizing plate having the pressure-sensitive adhesive layer is exposed to high temperature or the like, white voids due to shrinkage of the polarizing plate having the pressure-sensitive adhesive layer can be suppressed. desirable. Moreover, since the fall of durability by the fall of adhesive force does not produce easily that it is 5 MPa or less, it is preferable. Here, "it shows the storage elastic modulus of 0.10-5.0 MPa in 23-80 degreeC" means that also in any temperature of this range, the storage elastic modulus takes the value of the said range. Since the storage elastic modulus usually decreases gradually as the temperature rises, if the storage elastic modulus at 23 ° C. and 80 ° C. both fall within the above range, it can be considered that the adhesive layer exhibits the storage elastic modulus of the above range at the temperature in this range. there is. In addition, the storage elastic modulus of an adhesive layer can be measured with a commercially available viscoelasticity measuring apparatus, for example, the viscoelasticity measuring apparatus "DYNAMIC ANALYZER RDA II" by the REOMETRIC company.

It is preferable that it is 1.45-1.49, and, as for the average refractive index of the adhesive layer 6, it is more preferable that it is 1.46-1.47.

It is preferable that the value of the average refractive index of the adhesive layer 6 is the same as the value of the average refractive index of the 1st resin film 3, or it is smaller than the value of the average refractive index of the 1st resin film 3 . It is preferable that it is 0.12 or less, as for the difference of the average refractive index of the adhesive layer 6, and the average refractive index of the 1st resin film 3, it is more preferable that it is 0.10 or less, It is still more preferable that it is 0.08 or less.

The average refractive index of the pressure-sensitive adhesive layer 6 can be adjusted by changing the type of the base polymer or the type of the crosslinking agent.

This invention also includes the image display apparatus which laminated|stacked the polarizing plate which has the adhesive layer of this invention, and the image display panel. It is preferable to laminate|stack the polarizing plate which has an adhesive layer of this invention on the visual recognition side (in the case of a liquid crystal display panel, the opposite side of a backlight) of an image display panel. A liquid crystal display panel may be sufficient as an image display panel, and an organic electroluminescent display panel may be sufficient as it.

Example

Hereinafter, although an Example demonstrates this invention further in detail, this invention is not limited in any way by these Examples. In addition, "%" and "part" in an Example and a comparative example show "mass %" and "part by mass", respectively, unless otherwise indicated.

<Method for measuring refractive index of active energy ray-curable adhesive>

An active energy ray-curable adhesive was coated on one side of a stretched norbornene-based resin film [“Zeonoa Film” manufactured by Nippon Zeon Co., Ltd.] using a bar coater [manufactured by Daiichi Chemical Co., Ltd.], and UV irradiation device By [Fusion UV Systems Co., Ltd. product], ultraviolet rays were irradiated with an accumulated light amount of 600 mJ/cm 2 (UV-B) to obtain a cured product. The film thickness of the obtained hardened|cured material was about 30 micrometers.

The norbornene-based resin film was peeled off from the obtained cured product, and the refractive index (wavelength 589 nm) of the cured product layer was measured using a multi-wavelength Abbe refractometer [“DR-M2” manufactured by Atago Co., Ltd.] in an environment of 25°C.

The refractive index of the hardened|cured material of the active energy ray hardening-type adhesive agent a was 1.54, and the refractive index of the hardened|cured material of the active energy ray hardening-type adhesive agent b was 1.51.

<Preparation Example 1: Preparation of a polarizing film>

A polyvinyl alcohol film with an average degree of polymerization of about 2,400, a degree of saponification of 99.9 mol% or more and a thickness of 75 μm is immersed in pure water at 30° C., and then in an aqueous solution having a mass ratio of iodine/potassium iodide/water of 0.02/2/100 at 30°C It was immersed and dyed with iodine (iodine dyeing process). The polyvinyl alcohol film subjected to the iodine dyeing step was immersed in an aqueous solution having a mass ratio of potassium iodide/boric acid/water of 12/5/100 at 56.5° C. to perform boric acid treatment (boric acid treatment step).

After wash|cleaning the polyvinyl alcohol film which passed through the boric acid treatment process with 8 degreeC pure water, it dried at 65 degreeC, and obtained the polarizer in which the iodine adsorption-orientation is carried out to polyvinyl alcohol. At this time, it extended|stretched in the iodine dyeing process and the boric acid treatment process. The total draw ratio in such extending|stretching was 5.3 times, and the thickness of the obtained polarizer was 27 micrometers.

<Production Example 1: Preparation of a polarizing plate>

The resin film used for preparation of a polarizing plate is as follows.

Film A: 80 μm (meth) a film made of acrylic resin

Film B: A film made of a cycloolefin-based resin having an average refractive index of 1.53 at 50 µm (in-plane retardation (Re) = 50 nm, retardation in thickness direction (Rth) = 135 nm)

Film C: A resin cured layer X having a thickness of 50 nm and an average refractive index of 1.57 formed on one surface of a cycloolefin-based resin film (film B).

A corona discharge treatment was performed on one side of the film A, and the active energy ray-curable curable composition b was coated on the corona discharge treatment side so that the thickness after curing was set to about 3.5 µm. Then, the polarizer produced in Production Example 1 was bonded to the coated surface. Next, corona discharge treatment was performed on one side of the film B, and the corona discharge treatment side was coated with the active energy ray-curable curable composition a so that the thickness after curing was about 2.5 µm. The polarizer which has the film A produced above was superposed on the coating surface from the polarizer side, and it pressed and bonded using the bonding roll, and obtained the laminated body. From the film B side, ultraviolet rays were applied from the film B side so that the accumulated light amount was 400 mJ/cm 2 (UVB) using an ultraviolet irradiation device [the lamp was used as a “D bulb” manufactured by Fusion UV Systems Co., Ltd.] It was irradiated, and the adhesive layer on both sides was hardened, and the polarizing plate was produced. The structure of the obtained polarizing plate is film A (2nd resin film) / cured material layer (2nd cured material layer) of curable composition b / polarizing film / cured material layer (1st cured material layer) of curable composition a / film B (1st resin film), and the absolute value of the refractive index difference of the 1st hardened|cured material layer and 1st resin film was 0.01.

Example 1: Preparation of a polarizing plate having a pressure-sensitive adhesive layer

The organic solvent solution of the acrylic pressure-sensitive adhesive was coated on the release-treated surface of the 38 µm-thick polyethylene terephthalate film subjected to the release treatment with a die coater and dried to prepare a sheet-like pressure-sensitive adhesive layer having a release film. In addition, the thickness of the adhesive layer was 20 micrometers.

The release film was peeled off from the prepared sheet-like pressure-sensitive adhesive layer, and the refractive index (wavelength of 589 nm) of the pressure-sensitive adhesive layer was measured using a multi-wavelength Abbe refractometer [“DR-M2” manufactured by Atago Corporation] under a 25°C environment. The refractive index of the adhesive layer was 1.47.

<Preparation of a polarizing plate having an adhesive layer>

After corona-treating the surface of the film B (first resin film) of the polarizing plate, and bonding the release film and the opposite side (adhesive side) to the release film of the sheet-like adhesive prepared in Production Example 2 with a laminator, the temperature 23 ° C., It cured for 7 days on the conditions of 65% of relative humidity, and the polarizing plate which has the adhesive layer in which the adhesive layer was provided was obtained. This laminated body has the structure by which the peeling film was bonded on the adhesive layer.

<Creation of sheetfly>

Using a cutting device (manufactured by Ogino Seiki Co., Ltd., super cutter "PN1-600"), the polarizing plate having the pressure-sensitive adhesive layer, the polarizing plate having the pressure-sensitive adhesive from the film A side, the length of the polarizer in the stretching direction (MD) of 50 mm, It cut out so that it might become 50 mm in length of the direction (TD) which cross|intersects the extending|stretching direction of a polarizer.

<Evaluation of light leakage at the end>

After peeling a peeling film from the polarizing plate which has an obtained adhesive layer, the adhesive layer surface was adhere|attached at the center of a 0.7-mm-thick glass substrate ["Eagle XG" by a Corning company], and the laminated body was obtained. The obtained laminate was set on the backlight so that the polarizing plate part of 10 mm (MD) x 50 mm (TD) out of 50 mm x 50 mm protruded from the bright part of a backlight. Then, the polarizing plate (40 mm x 50 mm) in the bright part of a backlight and the whole bright part of a backlight were covered with the black acrylic board. The backlight was turned on, and the edge part of the polarizing plate was visually confirmed from the angle inclined at 85° (θ=85° in FIG. 3) from the front of the polarizing plate. The results were judged on the basis of the following criteria. A result is shown in Table 1.

<Criteria for light leakage>

(circle): The light leakage cannot be visually recognized.

(triangle|delta): light leakage can be visually visually recognized weakly.

x: Light leakage can be visually recognized strongly.

Example 2: Preparation of a polarizing plate

As a composition which forms a 1st hardened|cured material layer, except having used the curable composition b, it carried out similarly to Example 1, the polarizing plate which has an adhesive layer was produced, and the same evaluation was performed. A result is shown in Table 1.

Example 3: Preparation of a polarizing plate

A corona discharge treatment was performed on one side of the film A, and the active energy ray-curable curable composition b was coated on the corona discharge treatment side so that the thickness after curing was set to about 3.5 µm. Then, the polarizer produced in Production Example 1 was bonded to the coated surface. Next, corona discharge treatment was performed on the cycloolefin resin film surface of Film C, and the active energy ray-curable curable composition b was coated on the corona discharge treatment surface so that the thickness after curing was about 2.5 µm. The polarizer which has the film A produced above was superposed on the coating surface from the polarizer side, and it pressed and bonded using the bonding roll, and obtained the laminated body. The obtained laminate was irradiated with ultraviolet rays from the film C side using an ultraviolet irradiation device having a belt conveyor [the lamp used was "D Bulb" manufactured by Fusion UV Systems Co., Ltd.] so that the accumulated light amount was 400 mJ/cm 2 (UVB). Thus, the adhesive layer on both sides was cured to prepare a polarizing plate. The structure of the obtained polarizing plate is film A (2nd resin film) / cured material layer (2nd cured material layer) of curable composition b / polarizing film / cured material layer (1st cured material layer) of curable composition b / film C (Cycloolefin-based resin film/cured resin layer X), and the absolute value of the difference in refractive index between the first cured material layer and the cycloolefin-based resin film was 0.02.

It evaluated by carrying out similarly to Example 1 on the surface of the cured resin layer X, forming an adhesive layer. A result is shown in Table 1.

Example 4: Preparation of a polarizing plate

The same as in Example 3, except that the surface X of the cured resin layer of the film C was corona-discharged, and the corona-discharge-treated surface was coated with the active energy ray-curable curable composition a so that the thickness after curing was about 2.5 µm. to prepare a polarizing plate.

The structure of the obtained polarizing plate is film A (2nd resin film) / cured material layer (2nd cured material layer) of curable composition b / polarizing film / cured material layer (1st cured material layer) of curable composition a / film C (hardened resin layer X/cycloolefin resin film), and the absolute value of the refractive index difference of the 1st hardened|cured material layer and the resin hardened layer X was 0.03.

It evaluated by carrying out similarly to Example 1 on the surface of a cycloolefin resin film, forming an adhesive layer. A result is shown in Table 1.

Comparative Example 1: Preparation of a polarizing plate

Except having changed the active energy ray-curable composition a into the active energy ray-curable composition b, it carried out similarly to Example 4, the polarizing plate which has an adhesive layer was produced, and the same evaluation was performed. The structure of the polarizing plate which has the obtained adhesive layer is film A (2nd resin film) / cured material layer of curable composition b (2nd cured material layer) / polarizing film / cured material layer (1st cured material layer) of curable composition b )/film C (cured resin layer X/cycloolefin-based resin film)/adhesive layer, and the absolute value of the difference in refractive index between the first cured material layer and the cured resin layer was 0.06. A result is shown in Table 1.

Light leakage is suppressed even when the polarizing plate which has an adhesive layer of this invention is viewed from the side at 85 degrees from the surface of a polarizing plate substantially. Therefore, when the polarizing plate which has the adhesive layer of this invention is built in the display apparatus in which the height of the bezel provided in the display apparatus was abbreviate|omitted or a fall, light leakage is suppressed even if the edge part of a polarizing plate is exposed.

The polarizing plate having an adhesive layer of the present invention is useful because light leakage from the end of the polarizing plate is small even if it is built in a display device with a narrow bezel width, a display device with a low bezel height, or a display device with a bezel omitted .

1 Polarizing film
2 First cured material layer
3 first resin film
4 2nd cured material layer
5 Second resin film
6 adhesive layer
7 on-screen display panel
10 Polarizer
20 Polarizing plate with pressure-sensitive adhesive layer
30 image display device
θ Angle from the front of the polarizer

Claims (7)

A polarizing plate having a pressure-sensitive adhesive layer comprising a polarizing film, a first cured material layer, a first resin film, and an pressure-sensitive adhesive layer in this order,
The polarizing film and the first cured material layer are in direct contact with each other,
The first cured material layer and the first resin film are in direct contact with each other,
The first resin film and the pressure-sensitive adhesive layer are in direct contact,
The polarizing plate which has an adhesive layer whose absolute value of the difference of the average refractive index of a 1st hardened|cured material layer and the average refractive index of a 1st resin film is 0.03 or less. The polarizing plate according to claim 1, wherein the first cured material layer is a cured product of an active energy ray-curable adhesive composition. The polarizing plate according to claim 1 or 2, wherein the refractive index of the first cured material layer is 1.55 or less. The polarizing plate according to any one of claims 1 to 3, wherein the first resin film includes a film formed of a thermoplastic resin. The polarizing plate according to any one of claims 1 to 4, wherein the thickness of the first resin film is 6 µm or more. The polarizing plate in any one of Claims 1-5 provided with the 2nd resin film on the surface other than the 1st hardened|cured material layer of a polarizing film through a 2nd hardened|cured material layer. An image display panel, and the image display apparatus containing the polarizing plate which has an adhesive layer in any one of Claims 1-6 arrange|positioned on the visual recognition side of the said image display panel.

Images