CN114746776A

CN114746776A - Optical film with adhesive layer and liquid crystal panel

Info

Publication number: CN114746776A
Application number: CN202080080647.3A
Authority: CN
Inventors: 山本悟士; 木村智之; 外山雄祐
Original assignee: Nitto Denko Corp
Current assignee: Nitto Denko Corp
Priority date: 2019-12-13
Filing date: 2020-10-27
Publication date: 2022-07-12
Also published as: JP2021096308A; JP7016851B2; TWI772249B; TW202231461A; KR20220114013A; WO2021117365A1; TW202132102A; TWI765395B

Abstract

The optical film with the adhesive layer comprises an optical film, an adhesive layer and an antistatic layer containing conductive polymer. The difference in light transmittance of the optical film with an adhesive layer due to the difference in measurement area is 2% or less, which is represented by the difference between the maximum value and the minimum value of the light transmittance. The optical film with an adhesive layer includes an antistatic layer containing a conductive polymer, but unevenness is not easily visible on the display surface of the liquid crystal panel.

Description

Optical film with adhesive layer and liquid crystal panel

Technical Field

The present invention relates to an optical film with an adhesive layer and a liquid crystal panel.

Background

The liquid crystal display device includes, for example: the liquid crystal display device includes a liquid crystal panel having a structure in which an optical film such as a polarizing plate is disposed on a viewing side of a liquid crystal cell, and an illumination system for irradiating the liquid crystal panel with light. The liquid crystal display device displays an image by applying a voltage to a liquid crystal cell and adjusting the orientation of liquid crystal molecules contained in the liquid crystal cell.

In the liquid crystal display device, static electricity is generated during manufacturing, for example, when the optical film is bonded to the liquid crystal cell via the pressure-sensitive adhesive layer, or during use, for example, when a user touches the liquid crystal display device. The liquid crystal display device may be charged by the static electricity. If the liquid crystal display device is charged, the alignment of the liquid crystal molecules contained in the liquid crystal cell is disturbed, and a display failure occurs. In order to prevent display defects caused by electrification of the liquid crystal display device, it is known to dispose an ITO (indium tin oxide) layer on the surface of the liquid crystal cell on the optical film side, for example.

Patent document 1 discloses a laminated structure including a polarizing plate and a conductive layer containing a conductive polymer.

Documents of the prior art

Patent document

Patent document 1: japanese patent laid-open publication No. 2016-

Disclosure of Invention

Problems to be solved by the invention

In patent document 1, an attempt is made to replace the ITO layer with the conductive layer. However, according to the studies of the present inventors, it has been found that when the substitution is performed, unevenness in a spot shape tends to be visually recognized on the display surface of the liquid crystal panel; in addition, when the ITO layer is used, the above-described unevenness in the form of spots is not generally visually recognized.

The purpose of the present invention is to provide an optical film with a pressure-sensitive adhesive layer, which is not easily visible as unevenness on the display surface of a liquid crystal panel, despite having an antistatic layer comprising a conductive polymer.

Means for solving the problems

The invention provides an optical film with an adhesive layer, which comprises the optical film and the adhesive layer,

the optical film with the pressure-sensitive adhesive layer further comprises an antistatic layer comprising a conductive polymer,

the difference in light transmittance between the optical film with the pressure-sensitive adhesive layer and the measurement region is 2% or less, which is represented by the difference between the maximum value and the minimum value of the light transmittance.

In another aspect, the present invention provides a liquid crystal panel including:

the optical film with an adhesive layer of the present invention described above, and

a liquid crystal cell having a liquid crystal layer,

the liquid crystal cell includes a pair of transparent substrates and a liquid crystal layer disposed between the pair of transparent substrates,

no conductive layer is provided between the optical film with an adhesive layer and the liquid crystal cell.

ADVANTAGEOUS EFFECTS OF INVENTION

According to the present invention, it is possible to provide an optical film with a pressure-sensitive adhesive layer, which is less likely to cause unevenness to be visually recognized on a display surface of a liquid crystal panel, although the optical film includes an antistatic layer containing a conductive polymer.

Drawings

Fig. 1 is a cross-sectional view schematically showing an example of the optical film with an adhesive layer of the present invention.

Fig. 2 is a cross-sectional view schematically showing another example of the optical film with an adhesive layer of the present invention.

Fig. 3 is a cross-sectional view schematically showing another example of the optical film with an adhesive layer of the present invention.

Fig. 4 is a cross-sectional view schematically showing still another example of the optical film with an adhesive layer of the present invention.

Fig. 5 is a cross-sectional view schematically showing an example of a liquid crystal panel of the present invention.

Fig. 6 is a cross-sectional view schematically showing another example of the liquid crystal panel of the present invention.

Detailed Description

The present invention will be described in detail below. The following description is not intended to limit the present invention to the specific embodiments.

(optical film with adhesive layer)

As shown in fig. 1, the optical film with an adhesive layer 10 of the present embodiment includes an optical film 1, an antistatic layer 2, and an adhesive layer 3. The optical film 1, the antistatic layer 2, and the adhesive layer 3 of fig. 1 are sequentially laminated together. The antistatic layer 2 of fig. 1 is attached to the optical film 1 and the adhesive layer 3, respectively. In the case where the antistatic layer 2 is located between the optical film 1 and the adhesive layer 3, there is a tendency that deterioration of the antistatic layer 2 is suppressed. However, the order of disposing the optical film 1, the antistatic layer 2, and the pressure-sensitive adhesive layer 3 is not limited to the example of fig. 1. For example, the optical film 1 may also be located between the antistatic layer 2 and the adhesive layer 3. The surface of the adhesive layer 3 is usually exposed outside the optical film with an adhesive layer 10.

In the optical film 10 with an adhesive layer, the difference in light transmittance due to the difference in measurement area is represented by the maximum value T of the light transmittance_maxAnd a minimum value T_minDifference Δ T (═ T)_max－T_min) Expressed as 2% or less. The difference Δ T may be 1.8% or less, 1.6% or less, 1.5% or less, 1.2% or less, 1% or less, 0.8% or less, 0.5% or less, 0.2% or less, and further 0.1% or less. The lower limit of the difference Δ T is, for example, 0.01%. The difference Δ T can be evaluated as follows.

The surface of the adhesive layer-attached optical film 10 was provided with at least 30 measurement regions. Each measurement region is, for example, a circle having a diameter of 10 to 30 μm when viewed perpendicularly to the surface. Ensuring that the separation between the measurement areas is at least 5 mm. The area of the region in which the measurement region is set on the surface is, for example, 50cm²The above. The distance between the measurement regions that are farthest from each other is preferably 10cm or more. The measurement regions may be arranged at random positions or may be arranged regularly at positions corresponding to intersections of virtual grids set on the surface. Next, the total light transmittance in each measurement region was measured. The total light transmittance is a transmittance of light having a wavelength of 380 to 700 nm. The total light transmittance can be measured, for example, using a measuring apparatus capable of measuring the above-mentioned measurement region in accordance with the specification of Japanese Industrial standards (hereinafter, referred to as "JIS") L7361-1: 1997. The total light transmittance was measured using a D65 light source. The total light transmittance was measured by light incident from the optical film 1 side selected from the pressure-sensitive adhesive layer 3 and the optical film 1. The maximum value of the total light transmittance measured for each measurement region may be represented by T_maxSetting the minimum value as T_minThe difference is specified as Δ T.

When the total light transmittance is measured, a layer (for example, a hard coat layer) that does not affect the difference Δ T may be disposed on the surface of the optical film 10 with an adhesive layer.

If the ITO layer located between the liquid crystal cell and the optical film is replaced with an antistatic layer containing a high molecular polymer, the reflectance of external light in the liquid crystal panel decreases. The low reflectance of the liquid crystal panel enables high-definition images with good color tone to be visually recognized in the liquid crystal display device. However, according to the study by the present inventors, it was found that unevenness (typically, mottle) of the display surface, which is not visually recognized in a state where the ITO layer is provided, is clearly visually recognized due to the reduction of the reflected light caused by the replacement of the ITO layer; and the display surface unevenness is generated due to the light transmittance unevenness in the antistatic layer. Therefore, by setting the difference Δ T within a predetermined range, the display surface of the liquid crystal panel is less likely to be visually uneven although the antistatic layer containing the conductive polymer is provided.

[ optical film ]

The configuration of the optical film 1 is not limited as long as it can be used for a liquid crystal panel. The optical film 1 may be a single-layer film, or may be an optical laminate in which 2 or more layers of films are laminated.

The optical film 1 includes, for example, a polarizing plate. Fig. 2 shows an example of an optical film 10 with an adhesive layer, which includes the optical film 1 including a polarizing plate. The optical film 1 of fig. 2 is constituted by a polarizing plate 4.

The polarizing plate includes a polarizer and a transparent protective film. The transparent protective film is disposed in contact with, for example, a principal surface (surface having the largest area) of the polarizer. The polarizer may be disposed between the two transparent protective films. Examples of the polarizer include, but are not particularly limited to, polarizers obtained by uniaxially stretching a hydrophilic polymer film such as a polyvinyl alcohol film, a partially formalized polyvinyl alcohol film, or an ethylene-vinyl acetate copolymer partially saponified film, to which a dichroic material such as iodine or a dichroic dye is adsorbed; and polyene-based oriented films such as dehydrated polyvinyl alcohol and desalted polyvinyl chloride. The polarizer is preferably formed of a dichroic material such as a polyvinyl alcohol film or iodine.

The thickness of the polarizer is not particularly limited, and is, for example, 80 μm or less. The thickness of the polarizer may be 10 μm or less, preferably 1 to 7 μm. Such a thin polarizer has a small variation in thickness and is excellent in visibility. The size change of the thin polarizer is suppressed, and the durability is excellent. The polarizer can be thinned by using a thin polarizer.

As the material of the transparent protective film, for example: a thermoplastic resin excellent in transparency, mechanical strength, thermal stability, moisture barrier properties, isotropy and the like. Specific examples of such thermoplastic resins include cellulose resins such as cellulose triacetate, polyester resins, polyethersulfone resins, polysulfone resins, polycarbonate resins, polyamide resins, polyimide resins, polyolefin resins, (meth) acrylic resins, cyclic polyolefin resins (norbornene resins), polyarylate resins, polystyrene resins, polyvinyl alcohol resins, and mixtures thereof. The material of the transparent protective film may be a thermosetting resin or an ultraviolet-curable resin such as (meth) acrylic, urethane, acrylic urethane, epoxy, silicone, or the like. In the case where the polarizing plate has two transparent protective films, the materials of the two transparent protective films may be the same or different. For example, a transparent protective film made of a thermoplastic resin may be bonded to one main surface of the polarizer by an adhesive, and a transparent protective film made of a thermosetting resin or an ultraviolet curable resin may be bonded to the other main surface of the polarizer. The transparent protective film may contain 1 or more kinds of any additives.

The transparent protective film may have optical characteristics such as an antiglare characteristic and an antireflection characteristic. In this case, the reflectance of the liquid crystal panel can be further reduced. The further reduction in reflectance makes the unevenness of the display surface more clearly visible, but the difference Δ T in the antistatic layer 2 is set within a predetermined range, so that the unevenness of the display surface can be suppressed.

The transparent protective film may be a film that functions as a retardation film. In the present specification, a retardation film refers to a film having birefringence in the in-plane direction or the thickness direction. Examples of the film functioning as the retardation film include: a film obtained by stretching a polymer film, a film obtained by orienting and fixing a liquid crystal material, and the like.

The adhesive used for bonding the polarizer and the transparent protective film is not particularly limited as long as it is optically transparent, and examples thereof include: water-based, solvent-based, hot-melt, radical-curable, cation-curable, and the like adhesives, and water-based adhesives and radical-curable adhesives are preferred.

The thickness of the polarizing plate is, for example, 10 to 500. mu.m. The total light transmittance of the polarizing plate is not particularly limited, and is, for example, 30% to 50%.

The optical film 1 may include an antireflection layer. Fig. 3 shows an example of an optical film 10 with an adhesive layer, which includes the optical film 1 including an antireflection layer. The optical film 1 of fig. 3 is composed of a polarizing plate 4 and an antireflection layer 5. In the example of fig. 3, the antireflection layer 5 is located at the outermost layer. The antireflection layer 5 may be located on the most visible side or the outermost layer when the liquid crystal panel is formed by combining with a liquid crystal cell.

When the optical film 1 includes the antireflection layer 5, the reflectance of the liquid crystal panel can be further reduced. The further reduction in reflectance makes the unevenness of the display surface more clearly visible, but the difference Δ T in the antistatic layer 2 is set within a predetermined range, so that the unevenness of the display surface can be suppressed. In other words, in the case where the optical film 1 includes the antireflection layer 5, the effect of the present invention becomes more remarkable.

The antireflection layer 5 is, for example, an optical laminate in which 2 or more thin films are laminated based on a predetermined optical design. In the typical antireflection layer 5, a high refractive index layer is combined with a low refractive index layer. The antireflection layer 5 includes, for example, a 1 st high refractive index layer, a 1 st low refractive index layer, a 2 nd high refractive index layer, and a 2 nd low refractive index layer in this order. The 1 st high refractive index layer is, for example, in contact with the polarizing plate 4. The 2 nd low refractive index layer is, for example, located closest to the viewing side among these layers.

The refractive index of the high refractive index layer is, for example, in the range of 1.6 to 3.2. The refractive index of the low refractive index layer is lower than that of the high refractive index layer, and is, for example, 1.35 to 1.55, preferably 1.40 to 1.50. In the present specification, unless otherwise specified, "refractive index" refers to a value measured at a temperature of 25 ℃ by using light having a wavelength λ of 550nm in accordance with the specification of JIS K7105.

Examples of the material of the high refractive index layer include: metal oxides, metal nitrides. Specific examples of the metal oxide include titanium oxide (TiO)₂) Indium/tin oxide (ITO), niobium oxide (Nb)₂O₅) Yttrium oxide (Y)₂O₃) Indium oxide (In)₂O₃) Tin oxide (SnO)₂) Zirconium oxide (ZrO)₂) Hafnium oxide (HfO)₂) Antimony oxide (Sb)₂O₃) Tantalum oxide (Ta)₂O₅) Zinc oxide (ZnO), tungsten oxide (WO)₃). Specific examples of the metal nitride include silicon nitride (Si)₃N₄). High refractive index layer is preferredContaining niobium oxide (Nb)₂O₅) Or titanium oxide (TiO)₂). The high refractive index layer made of a metal oxide or a metal nitride has a refractive index of, for example, 2.00 to 2.60, preferably 2.10 to 2.45.

Examples of the material of the low refractive index layer include: metal oxides, metal fluorides. Specific examples of the metal oxide include silicon oxide (SiO)₂). Specific examples of the metal fluoride include magnesium fluoride and fluorosilicic acid. The material of the low refractive index layer is preferably magnesium fluoride and fluorosilicic acid from the viewpoint of the refractive index, and is preferably silicon oxide from the viewpoint of ease of production, mechanical strength, moisture resistance, and the like, and silicon oxide is preferable if various characteristics are comprehensively considered.

The material of the low refractive index layer may be a cured product of a curable fluorine-containing resin. The curable fluorine-containing resin has, for example, a structural unit derived from a fluorine-containing monomer and a structural unit derived from a crosslinkable monomer. Specific examples of the fluorine-containing monomer include: fluoroolefins (e.g., vinyl fluoride, vinylidene fluoride, tetrafluoroethylene, hexafluoroethylene, hexafluoropropylene, and perfluoro-2, 2-dimethyl-1, 3-dioxole), partially or completely fluorinated alkyl (meth) acrylate derivatives (e.g., Viscoat 6FM (manufactured by Osaka Kagaku Co., Ltd.), and M-2020 (manufactured by Daikin Co., Ltd.), and completely or partially fluorinated vinyl ethers). Examples of the crosslinkable monomer include: a (meth) acrylate monomer having a crosslinkable functional group in the molecule, such as glycidyl methacrylate; (meth) acrylate monomers having a functional group such as a carboxyl group, a hydroxyl group, an amino group, or a sulfonic acid group ((meth) acrylic acid, hydroxymethyl (meth) acrylate, hydroxyalkyl (meth) acrylate, allyl (meth) acrylate, etc.). The fluorine-containing resin may have a structural unit derived from a monomer other than the above-mentioned compounds (for example, an olefin monomer, (meth) acrylate monomer, or styrene monomer).

The antireflection layer 5 may be a known antireflection layer.

The optical film 1 may contain other layers than the above-described layers. The optical film 1 may include 1 or 2 or more other layers. The other layer may be a single layer or an optical laminate. The other layer may be located on the viewing side of the polarizing plate 4 or between the polarizing plate 4 and the antireflection layer 5. Examples of the other layers include: a polarizing plate, a reflection plate, a retardation film, a viewing angle compensation film, a brightness enhancement film, a surface treatment layer, a surface protection film, a transparent substrate, and an adhesive layer. The retardation film includes 1/2 wave plates and 1/4 wave plates. Examples of the surface treatment layer include: hard coating, anti-dazzle processing layer, anti-adhesion layer. However, the other layers are not limited to the above examples.

Fig. 4 shows an example of an optical film 10 with a pressure-sensitive adhesive layer, which includes the optical film 1 including another layer. The optical film 1 of fig. 4 includes a transparent substrate 6 and an adhesive layer 7 as other layers. The optical film 1 of fig. 4 has the same configuration as the optical film 1 of fig. 3, except that the transparent substrate 6 and the pressure-sensitive adhesive layer 7 are provided between the polarizing plate 4 and the antireflection layer 5. The transparent substrate 6 and the adhesive layer 7 are in contact with the antireflection layer 5 and the polarizing plate 4, respectively. The transparent substrate 6 and the pressure-sensitive adhesive layer 7 are in contact with each other.

Examples of the material of the transparent substrate 6 include: glass and polymers. The transparent substrate 6 is preferably made of glass. The transparent substrate 6 made of glass is also referred to as "cover glass". Examples of the polymer constituting the transparent substrate 6 include: polyethylene terephthalate, polycycloolefins, polycarbonates. The thickness of the transparent substrate 6 made of glass is, for example, 0.1mm to 1 mm. The thickness of the transparent substrate 6 made of a polymer is, for example, 10 to 200 μm.

As the pressure-sensitive adhesive layer 7, the same pressure-sensitive adhesive layer as the pressure-sensitive adhesive layer 3 described later can be used. The Adhesive layer 7 preferably contains a commercially available Optically Clear Adhesive (OCA). The adhesive layer 7 can be formed using an adhesive tape such as luciac (registered trademark) CS9621T, for example.

As the material of the hard coat layer, for example, a thermoplastic resin, a material cured by heat or radiation, or the like can be used. Examples of the material that is cured by heat or radiation include: a thermosetting resin; radiation curable resins such as ultraviolet curable resins and electron beam curable resins. According to the ultraviolet curable resin, the cured resin layer can be formed with good processing efficiency by a curing treatment by ultraviolet irradiation. Examples of the curable resin include: polyester resins, acrylic resins, urethane resins, amide resins, silicone resins, epoxy resins, melamine resins, and the like. The curable resin includes, for example: and monomers, oligomers, and polymers such as polyesters, acrylics, urethanes, amides, silicones, epoxies, and melamines. The material of the hard coat layer is preferably a radiation-curable resin, and particularly preferably an ultraviolet-curable resin, from the viewpoint of high processing speed and less damage to the substrate by heat. The ultraviolet curable resin preferably contains, for example, a compound having an ultraviolet polymerizable functional group, particularly an acrylic monomer or oligomer having 2 or more, preferably 3 to 6 functional groups. For example, a photopolymerization initiator is blended in the ultraviolet curable resin.

The material of the antiglare layer is not particularly limited, and for example, a radiation curable resin, a thermosetting resin, a thermoplastic resin, or the like can be used.

The surface treatment layer may have conductivity by containing a conductive material. As the conductive material, a conductive polymer that can be contained in the antistatic layer 2 can be cited.

The surface protective film may be disposed on the surface treatment layer, or may be disposed on the polarizing plate 4 or the antireflection layer 5. The surface protective film includes, for example, a support film and an adhesive layer disposed on at least one surface of the support film. The adhesive layer of the surface protective film may contain a light release agent, a conductive material, or the like. In the case where the adhesive layer of the surface protective film contains a conductive material, the surface protective film may be attached to the surface treatment layer, and then the surface protective film may be peeled off to contain the conductive material in the surface treatment layer, thereby imparting a conductive function to the surface. As the conductive material, a conductive polymer that can be contained in the antistatic layer 2 can be cited. In order to impart a conductive function to the surface of the surface treatment layer by peeling off the surface protective film, it is preferable that the adhesive layer of the surface protective film contains a light peeling agent together with the conductive material. Examples of the light release agent include: silicone resins such as polyorganosiloxane. The conductive function imparted to the surface of the surface treatment layer can be appropriately adjusted by the amounts of the conductive material and the light release agent used.

The other layer may include an easy adhesion layer for improving adhesion between members. In the case where the other layer is an easy adhesion layer, the easy adhesion layer may be disposed between the polarizer 4 and the antistatic layer 2. Instead of the easy adhesion layer, the surface of the polarizer 4 on the antistatic layer 2 side may be subjected to an easy adhesion treatment such as corona treatment or plasma treatment.

The effect of the present invention is more remarkable the lower the reflectance of the optical film 1 to external light is. The light reflectance Y of the optical film 1 is, for example, 5.0% or less, and may be 4.0% or less, 3.0% or less, 2.0% or less, 1.5% or less, 1.1% or less, 1.0% or less, 0.9% or less, 0.8% or less, 0.7% or less, 0.6% or less, and further 0.5% or less. The lower limit of the light reflectance Y is, for example, 0.01% or more. The light reflectance Y of 1.5% or less can be realized by the antireflection layer 5, for example. The optical film with an adhesive layer 10 having the light reflectance Y of 1.5% or less, preferably 1.1% or less, and the liquid crystal panel provided with the optical film with an adhesive layer 10 are suitable for applications requiring good visibility, for example, a vehicle-mounted display.

The light reflectance Y can be specified by the following method. First, the optical film 10 with an adhesive layer is attached to the alkali-free glass via the adhesive layer 3. The alkali-free glass is a glass substantially free from alkali components (alkali metal oxides). Specifically, the weight ratio of the alkali component in the alkali-free glass is, for example, 1000ppm or less, and further 500ppm or less. The alkali-free glass is, for example, plate-shaped and has a thickness of 0.5mm or more. Next, a black film was attached to the surface of the alkali-free glass opposite to the surface to be bonded to the optical film 10 with the pressure-sensitive adhesive layer. Next, light from CIE standard illuminant D65 was made incident on the surface of the adhesive-layer-attached optical film 10 at an incident angle of 5 °. The spectral reflectance in the range of 360nm to 740nm of the specular reflection light generated in this case is specified, and the tristimulus values (X, Y and Z) in the XYZ color system (CIE1931) are specified on the basis of the spectral reflectance. The tristimulus values are specified in detail in JIS Z8701: 1999. The Y value of the tristimulus values may be specified as the light reflectance Y.

[ antistatic layer ]

The antistatic layer 2 contains a conductive polymer as a conductive material. The conductive polymer may be a composite with the dopant. The antistatic layer 2 may further contain an ionic surfactant, conductive fine particles, an ionic compound, and the like. The antistatic layer 2 comprising a conductive polymer may have high transparency and full light transmittance, low haze, good appearance, excellent antistatic effect, and stable antistatic effect in a high-temperature or high-humidity environment. Even when the antistatic layer 2 containing a conductive polymer is disposed between the liquid crystal cell and the polarizer, polarized light extinction is less likely to occur, and the contrast of an image displayed by the liquid crystal display device is less likely to be lowered. The antistatic layer 2 containing a conductive polymer can lower the refractive index, for example, as compared with a layer containing only conductive fine particles as a conductive material. Therefore, the antistatic layer 2 including the conductive polymer is suitable for reducing the reflectance of the liquid crystal panel.

The content of the conductive polymer in the antistatic layer 2 may be, for example, 0.01 wt% to 99.9 wt%, or 1.0 wt% to 95.0 wt%. In the present specification, "wt%" means wt%.

Examples of the conductive polymer include: polythiophene, polyaniline, polypyrrole, polyquinoxaline, polyacetylene, polyphenylene ethylene, polynaphthalene and derivatives thereof. The antistatic layer 2 may contain 1 or 2 or more of these conductive polymers. As the conductive polymer, polythiophene, polyaniline, and derivatives thereof are preferable, and polythiophene derivatives are particularly preferable. Polythiophene, polyaniline, and derivatives thereof function as a conductive polymer having water solubility or water dispersibility, for example. When the conductive polymer is water-soluble or water-dispersible, the antistatic layer 2 can be prepared using an aqueous solution or aqueous dispersion of the conductive polymer. In this case, since the antistatic layer 2 is produced without using a nonaqueous organic solvent, the optical film 1 such as the polarizing plate 4 can be prevented from being altered by the organic solvent.

The conductive polymer may have a hydrophilic functional group. Examples of the hydrophilic functional group include: sulfo groups, amino groups, amide groups, imine groups, hydroxyl groups, mercapto groups, hydrazine groups, carboxyl groups, sulfate groups, phosphate groups, and salts thereof (e.g., quaternary ammonium salt groups). When the conductive polymer has a hydrophilic functional group, the conductive polymer tends to be easily dissolved in water, or the conductive polymer in a fine particle form tends to be easily dispersed in water.

From the viewpoint of conductivity and chemical stability, the conductive polymer is preferably poly (3, 4-disubstituted thiophene). Examples of the poly (3, 4-disubstituted thiophene) include poly (3, 4-alkylenedioxythiophene) and poly (3, 4-dialkoxythiophene), and poly (3, 4-alkylenedioxythiophene) is preferable. The poly (3, 4-alkylenedioxythiophene) has, for example, a structural unit represented by the following formula (I).

[ chemical formula 1]

In the formula (I), R¹For example, an alkylene group having 1 to 4 carbon atoms. The alkylene group may be linear or branched. Examples of the alkylene group include: methylene, 1, 2-ethylene, 1, 3-propylene, 1, 4-butylene, 1-methyl-1, 2-ethylene, 1-ethyl-1, 2-ethylene, 1-methyl-1, 3-propylene and 2-methyl-1, 3-propylene, preferably methylene, 1, 2-ethylene, 1, 3-propylene, more preferably 1, 2-ethylene. The conductive polymer is preferably poly (3, 4-methylenedioxythiophene) (PEDOT).

Examples of the dopant include polyanions. In the case where the conductive polymer is polythiophene (or a derivative thereof), the polyanion may form an ion pair with the polythiophene (or a derivative thereof) to stably disperse the polythiophene (or a derivative thereof) in water. The polyanion is not particularly limited, and examples thereof include: carboxylic acid polymers such as polyacrylic acid, polymaleic acid, and polymethacrylic acid; sulfonic acid polymers such as polystyrenesulfonic acid, polyvinylsulfonic acid and polyisoprene sulfonic acid. The polyanion may be a copolymer of a vinylcarboxylic acid or a vinylsulfonic acid with another monomer. Examples of the other monomers include: (meth) acrylate compounds; aromatic vinyl compounds such as styrene and vinylnaphthalene. The polyanion is particularly preferably polystyrene sulfonic acid (PSS). Examples of the conductive polymer in the form of a composite with a dopant include: a complex of poly (3, 4-methylenedioxythiophene) and polystyrene sulfonic acid (PEDOT/PSS).

Examples of the ionic surfactant include: quaternary ammonium salt type,

Cationic surfactants such as salt type and sulfonium salt type; anionic surfactants such as carboxylic acid type, sulfonic acid ester type, sulfuric acid ester type, phosphoric acid ester type, and phosphorous acid ester type surfactants; sulfobetaine type, alkylbetaine type, and alkylimidazole

A betaine-type isozwitterionic surfactant; nonionic surfactants such as polyol derivatives, β -cyclodextrin inclusion compounds, sorbitan fatty acid monoesters, sorbitan fatty acid diesters, polyoxyalkylene derivatives, and amine oxides.

Examples of the conductive fine particles include: metal oxide fine particles such as tin oxide, antimony oxide, indium oxide, and zinc oxide, and tin oxide fine particles are preferable. Examples of the material of the tin oxide-based fine particles include: tin oxide, antimony-doped tin oxide, indium-doped tin oxide, aluminum-doped tin oxide, tungsten-doped tin oxide, a titanium oxide-cerium oxide-tin oxide composite, a titanium oxide-tin oxide composite, and the like. The conductive fine particles have an average particle diameter of, for example, 1 to 100nm, preferably 2 to 50 nm. The average particle diameter of the conductive fine particles is, for example, a particle diameter corresponding to 50% of the volume accumulation in the particle size distribution measured by a laser diffraction particle sizer or the like (d 50).

Examples of the ionic compound include: alkali metal salts and/or organic cation-anion salts. Examples of the alkali metal salt include: organic and inorganic salts of alkali metals. In the present specification, the organic cation-anion salt means an organic salt containing an organic cation. The anion contained in the organic cation-anion salt may be an organic anion or an inorganic anion. Organic cation-anion salts are sometimes referred to as ionic liquids or ionic solids.

Examples of the alkali metal ion contained in the alkali metal salt include: lithium ion, sodium ion and potassium ion, and lithium ion is preferable.

Examples of the anion contained in the organic salt of an alkali metal include: CH (CH)₃COO^-、CF₃COO^-、CH₃SO₃ ^-、CF₃SO₃ ^-、(CF₃SO₂)₃C^-、C₄F₉SO₃ ^-、C₃F₇COO^-、(CF₃SO₂)(CF₃CO)N^-、^-O₃S(CF₂)₃SO₃ ^-、(CN)₂N^-And anions represented by the following general formulae (1) to (4).

(1)(C_nF_2n+1SO₂)₂N^-(wherein n is an integer of 1 to 10)

(2)CF₂(C_mF_2mSO₂)₂N^-(wherein m is an integer of 1 to 10)

(3)^-O₃S(CF₂)_lSO₃ ^-(wherein l is an integer of 1 to 10)

(4)(C_pF_2p+1SO₂)N^-(C_qF_2q+1SO₂) (wherein p and q are each independently an integer of 1 to 10.)

The anion contained in the organic salt of an alkali metal preferably contains a fluorine atom. The organic salt of an alkali metal functions as an ionic compound having excellent ionic dissociation properties by the anion containing a fluorine atom.

As alkali metalsExamples of the anion contained in the inorganic salt include: cl^-、Br^-、I^-、AlCl₄ ^-、Al₂Cl₇ ^-、BF₄ ^-、PF₆ ^-、ClO₄ ^-、NO₃ ^-、AsF₆ ^-、SbF₆ ^-、NbF₆ ^-、TaF₆ ^-、(FSO₂)₂N^-、CO₃ ^2-And so on.

As the anion contained in the alkali metal salt, (CF) is preferred₃SO₂)₂N^-、(C₂F₅SO₂)₂N^-The (perfluoroalkylsulfonyl) imide represented by the above general formula (1) is particularly preferably (CF)₃SO₂)₂N^-Bis (trifluoromethanesulfonyl) imide as shown.

Examples of the organic salt of an alkali metal include: sodium acetate, sodium alginate, sodium lignosulfonate, sodium toluenesulfonate, LiCF₃SO₃、Li(CF₃SO₂)₂N、Li(C₂F₅SO₂)₂N、Li(C₄F₉SO₂)₂N、Li(CF₃SO₂)₃C、KO₃S(CF₂)₃SO₃K、LiO₃S(CF₂)₃SO₃K, etc., preferably LiCF₃SO₃、Li(CF₃SO₂)₂N、Li(C₂F₅SO₂)₂N、Li(C₄F₉SO₂)₂N、Li(CF₃SO₂)₃C, more preferably Li (CF)₃SO₂)₂N、Li(C₂F₅SO₂)₂N、Li(C₄F₉SO₂)₂And N is added. The organic salt of an alkali metal is preferably a fluorine-containing imide lithium salt, and particularly preferably a (perfluoroalkyl sulfonyl) imide lithium salt.

Examples of the inorganic salt of an alkali metal include: lithium perchlorate and lithium iodide. .

Examples of the organic cation contained in the organic cation-anion salt include: pyridine compound

Cation, piperidine

Cation, pyrrolidine

Cation, cation having pyrroline skeleton, imidazole

Cationic, tetrahydropyrimidines

Cationic dihydropyrimidines

Cationic, pyrazoles

Cationic pyrazolines

Cation, tetraalkylammonium cation, trialkylsulfonium cation, tetraalkyl

Cations, and the like.

Examples of the anion contained in the organic cation-anion salt include: cl^-、Br^-、I^-、AlCl₄ ^-、Al₂Cl₇ ^-、BF₄ ^-、PF₆ ^-、ClO₄ ^-、NO₃ ^-、CH₃COO^-、CF₃COO^-、CH₃SO₃ ^-、CF₃SO₃ ^-、(CF₃SO₂)₃C^-、AsF₆ ^-、SbF₆ ^-、NbF₆ ^-、TaF₆ ^-、(CN)₂N^-、C₄F₉SO₃ ^-、C₃F₇COO^-、(CF₃SO₂)(CF₃CO)N^-、(FSO₂)₂N^-、^-O₃S(CF₂)₃SO₃ ^-And anions represented by the above general formulae (1) to (4). The anion contained in the organic cation-anion salt preferably contains a fluorine atom. The organic cation-anion salt functions as an ionic compound having excellent ionic dissociation properties by the anion containing a fluorine atom.

The ionic compound is not limited to the alkali metal salt and the organic cation-anion salt, and examples thereof include: inorganic salts such as ammonium chloride, aluminum chloride, copper chloride, ferrous chloride, ferric chloride, ammonium sulfate, etc. The conductive material may contain 1 or 2 or more of the above ionic compounds.

The conductive material that can be contained in the antistatic layer 2 is not limited to the above materials. As the conductive material, for example: carbon materials such as acetylene black, ketjen black, natural graphite, and artificial graphite; titanium black; a cationic conductive group such as a quaternary ammonium salt, a zwitterionic conductive group such as a betaine compound, an anionic conductive group such as a sulfonate, a homopolymer of a monomer having a nonionic conductive group such as glycerin, or a copolymer of the monomer and another monomer (for example, a polymer having ionic conductivity such as a polymer having a structural unit derived from an acrylate or methacrylate having a quaternary ammonium salt group); a material (permanent antistatic agent) obtained by alloying a hydrophilic polymer such as a copolymer of ethylene and methacrylic acid ester with an acrylic resin or the like.

The antistatic layer 2 may contain other materials than the conductive material. Examples of the other materials include: adhesive, leveling agent and antioxidant. The antistatic layer 2 preferably contains a leveling agent. The leveling agent may be contained in the coating liquid at the time of producing the antistatic layer 2. It is preferable that the coating liquid contains a conductive aid in addition to the leveling agent. When the coating liquid contains the leveling agent and the conductive auxiliary agent, the thickness unevenness of the antistatic layer 2 can be suppressed, and thus the difference Δ T can be suppressed. The binder contained in the coating liquid also has the effect of improving the film formability of the antistatic layer 2 and suppressing thickness unevenness. From this viewpoint, it is more preferable that the coating liquid contains a binder in addition to the leveling agent and the conductive aid.

The antistatic layer 2 may be a layer formed from a coating liquid containing a leveling agent and a conductive auxiliary agent, or may be a layer formed from a coating liquid containing a leveling agent, a conductive auxiliary agent, and a binder.

Examples of the binder include: comprises

Oxazoline-based polymer, polyurethane resin, polyester resin, acrylic resin, polyether resin, cellulose resin, polyvinyl alcohol resin, epoxy resin, polyvinyl pyrrolidone, polystyrene resin, polyethylene glycol, pentaerythritol, etc., preferably contains

The oxazoline-based polymer, the polyurethane-based resin, the polyester-based resin, and the acrylic resin are preferable, and the polyurethane-based resin is particularly preferable. The antistatic layer 2 may contain 1 or 2 or more of these binders. The content of the binder in the antistatic layer 2 is, for example, 1.0 to 1000 parts by weight, preferably 10 to 900 parts by weight, based on 100 parts by weight of the conductive polymer.

Examples of the leveling agent include: a compound which imparts a low surface tension to the coating liquid for producing the antistatic layer 2. Due to the action of the leveling agent, the flatness of the surface of the coating film formed by coating the coating liquid is improved. Specific leveling agents include, for example: polysiloxanes such as dimethylpolysiloxane and polyether-modified siloxane, polyalkylene oxide, fluorine compounds, and the like. The antistatic layer 2 may contain 1 or 2 or more of these leveling agents. The content of the leveling agent in the antistatic layer 2 is, for example, 0.1 to 60 parts by weight, preferably 1.0 part by weight or more, based on 100 parts by weight of the conductive polymer.

Examples of the conductive assistant include: an organic compound having a polar group. Examples of polar groups are amide, hydroxyl and sulfinyl. The organic compound may have 2 or more polar groups. Since the dispersibility of the conductive polymer in the coating liquid is improved, the organic compound is preferably a low-molecular compound having a molecular weight of 500 or less, because the organic compound has an excellent effect as a conductive aid for improving the conductivity of the antistatic layer 2 and can more reliably suppress the thickness unevenness of the antistatic layer 2 by penetrating into the gaps between the conductive polymers. In order to stably form the antistatic layer 2, the organic compound has a boiling point of 100 ℃ or higher, preferably 180 ℃ or higher.

Specific examples of the conductive assistant include: dimethyl sulfoxide, N-dimethylacetamide, N-methylformamide, N-dimethylformamide, acetamide, N-ethylacetamide, N-phenyl-N-propylacetamide, benzamide, N-methylpyrrolidone, beta-lactam, gamma-lactam, delta-lactam, epsilon-caprolactam, laurolactam, ethylene glycol, diethylene glycol, propylene glycol, trimethylene glycol, beta-thiodiglycol, triethylene glycol, tripropylene glycol, 1, 4-butanediol, 1, 5-pentanediol, 1, 3-butanediol, 1, 6-hexanediol, neopentyl glycol, catechol, cyclohexanediol, cyclohexanedimethanol, glycerol, erythritol, isomalt (インマトール), lactitol, maltitol, and mixtures thereof, Mannitol, sorbitol, xylitol, and sucrose. The coating liquid may contain 1 or 2 or more of these conductive aids. The content of the conductive aid in the coating liquid is, for example, 0.1 to 30% by weight, preferably 0.5 to 10% by weight, based on the total amount of the conductive aid and the solvent.

The thickness of the antistatic layer 2 is, for example, 5nm to 180nm, preferably 150nm or less, more preferably 120nm or less, further preferably 100nm or less, particularly preferably 80nm or less, and particularly preferably 50nm or less. The thickness of the antistatic layer 2 may be 10nm or more, or 20nm or more.

The anchoring force of the antistatic layer 2 to the optical film 1 is, for example, 10.0N/25mm or more, preferably 12.0N/25mm or more, more preferably 14.0N/25mm or more, and further preferably 18.0N/25mm or more. The adhesive tends to improve the adhesion and adhesiveness (anchoring force) of the antistatic layer 2 to the optical film 1.

The anchoring force can be measured by the following method. First, the optical film 10 with an adhesive layer to be evaluated was cut into a width of 25mm × a length of 150mm to prepare a test piece. Next, the entire surface of the optical film 1 included in the test piece was superimposed on a test plate made of stainless steel by a double-sided tape, and a 2kg roller was reciprocated 1 time to press-bond them. Next, the pressure-sensitive adhesive layer 3 included in the test piece was superposed on the evaluation sheet, and a 2kg roller was reciprocated 1 time to press-bond them. The evaluation sheet has a size of 30mm in width × 150mm in length, and is not particularly limited as long as it is not peeled from the pressure-sensitive adhesive layer 3 in the test. For example, an ITO film (125Tetlight OES (manufactured by Touchi industries, Ltd.)) can be used as the evaluation sheet. Next, the pressure-sensitive adhesive layer 3 and the antistatic layer 2 were peeled from the optical film 1 at a peeling angle of 180 ° and a tensile speed of 300 mm/min while holding the evaluation sheet using a commercially available tensile testing machine, and the average value of the peeling force at that time was specified as the anchoring force. The above test was carried out in an atmosphere of 23 ℃.

The surface resistivity of the antistatic layer 2 is, for example, 1.0X 10²Ω/□～1.0×10¹²Omega/□. The upper limit of the surface resistivity may be 1.0X 10¹¹Omega/□ below, 1.0X 10⁸Omega/□ below, 1.0X 10⁷Omega/□ below, 1.0X 10⁶Omega/□ below, 1.0X 10⁵Omega/□ or less, and further 1.0X 10⁴Omega/□ or less. The lower the surface resistivity, the higher the antistatic performance of the antistatic layer 2. On the other hand, in the case where the liquid crystal panel has a touch sensing function, the lower limit of the surface resistivity is more than 1.0 × 10 in order to suppress charging of the liquid crystal panel while maintaining good touch sensitivity of the liquid crystal panel⁵Omega/□ may be 1.0X 10⁶Omega/□ or more, and further 1.0X 10⁷Omega/□ or more. The surface resistivity can be determined, for example, by the composition of the antistatic layer 2 and/orThe thickness is controlled. The larger the thickness is, the smaller the surface resistivity of the antistatic layer 2 is generally, with the same composition.

The surface resistivity of the antistatic layer 2 can be specified by the following method. First, a laminate in which the surface of the antistatic layer 2 is exposed to the outside is prepared. Examples of such a laminate include: a laminate L comprising an optical film 1 and an antistatic layer 2. Next, the surface resistivity of the antistatic layer 2 in the prepared laminate L was measured. The surface resistivity of the antistatic layer 2 can be measured according to the method specified in JIS K6911: 1995. The measurement can be carried out using a measuring apparatus according to the method prescribed in JIS K6911:1995, for example, Hiresta-UP MCP-HT450 (surface resistivity of 1.0X 10 in the case of surface resistivity, manufactured by Mitsubishi Chemical Analyticch Co., Ltd. (Ltd.))⁵Omega/□ or above) or Loresta-GP MCP-T600 (at a surface resistivity of less than 1.0X 10)⁵In the case of omega/□),

the loss a of the total light transmittance by the antistatic layer 2 is, for example, 0.9% or less, preferably 0.8% or less, more preferably 0.6% or less, further preferably 0.5% or less, particularly preferably 0.4% or less, and particularly preferably less than 0.2%. The lower limit of the loss A is not particularly limited, but is, for example, 0.01%. The loss a can be specified by the following method. First, the total light transmittance T1 of the optical film 1 and the total light transmittance T2 of the laminate L including the optical film 1 and the antistatic layer 2 were measured. The total light transmittance T2 of the laminate L is a value when light is incident from the optical film 1 side. The difference between the total light transmittance T1 and the total light transmittance T2 (T1 to T2) can be specified as loss a.

The antistatic layer 2 can be produced, for example, by the following method. First, a coating liquid containing a conductive material is prepared. The coating liquid is usually a solution or a dispersion. The solvent of the coating liquid is, for example, water, and may further contain a water-soluble organic solvent. In the case where the coating liquid contains a conductive aid as an organic compound, the solvent preferably further contains a water-soluble organic solvent. The water-soluble organic solvent improves the dispersibility of the conductive aid, and thereby the thickness unevenness of the antistatic layer 2 can be more reliably suppressed. When the solvent further contains a water-soluble organic solvent, the content of the organic solvent in the solvent is, for example, 1.0 to 99.9 wt%, preferably 5.0 wt% or more. Examples of the water-soluble organic solvent include: alcohols such as methanol, ethanol, n-propanol, isopropanol, n-butanol, isobutanol, sec-butanol, tert-butanol, n-pentanol, isopentanol, sec-pentanol, tert-pentanol, 1-ethyl-1-propanol, 2-methyl-1-butanol, n-hexanol, and cyclohexanol.

The coating liquid preferably contains a leveling agent and a conductive aid, and more preferably contains a leveling agent, a conductive aid and a binder.

The solid content concentration in the coating liquid is, for example, 0.1 to 5.0 wt%, preferably 0.3 wt% or more. When the solid content concentration is within these ranges, the thickness unevenness of the antistatic layer 2 can be further suppressed.

Next, the coating liquid is applied to the surface of the optical film 1. The resultant coating film was dried to produce the antistatic layer 2 on the optical film 1.

[ adhesive layer ]

The adhesive layer 3 is a layer containing an adhesive. Examples of the binder contained in the binder layer 3 include: rubber-based adhesives, acrylic-based adhesives, silicone-based adhesives, urethane-based adhesives, vinyl alkyl ether-based adhesives, polyvinyl pyrrolidone-based adhesives, polyacrylamide-based adhesives, cellulose-based adhesives, and the like. The pressure-sensitive adhesive contained in the pressure-sensitive adhesive layer 3 is preferably an acrylic pressure-sensitive adhesive in view of excellent optical transparency, having suitable adhesive properties such as wettability, cohesiveness and adhesiveness, and being excellent in weather resistance and heat resistance.

The acrylic adhesive contains a (meth) acrylic polymer as a base polymer. The (meth) acrylic polymer contains, for example, a structural unit derived from a (meth) acrylate ester as a main component. In the present specification, "(meth) acrylic acid" means acrylic acid and/or methacrylic acid. "principal component" means the structural unit present in the polymer in the greatest amount on a weight basis.

The number of carbon atoms of an ester moiety (a moiety other than a (meth) acryloyl group) contained in a (meth) acrylate for forming the main skeleton of the (meth) acrylic polymer is not particularly limited, and is, for example, 1 to 18. The ester moiety of the (meth) acrylate may contain an aromatic ring such as a phenyl group or a phenoxy group, or may contain an alkyl group. The alkyl group may be linear or branched. The (meth) acrylic polymer may contain 1 or 2 or more kinds of structural units derived from (meth) acrylic acid esters. In the (meth) acrylic polymer, the average number of carbon atoms of an ester moiety contained in a structural unit derived from a (meth) acrylate ester is preferably 3 to 9. From the viewpoints of adhesion properties, durability, adjustment of retardation, adjustment of refractive index, and the like, the (meth) acrylic polymer preferably has a structural unit derived from a (meth) acrylate containing an aromatic ring. By adjusting the retardation of the pressure-sensitive adhesive layer 3 with the aromatic ring-containing (meth) acrylate, light leakage of the liquid crystal display device caused by stretching of the pressure-sensitive adhesive layer 3 due to thermal shrinkage of the optical film 1 can be suppressed. Further, the (meth) acrylate is suitable for adjusting the refractive index of the adhesive layer 3 to reduce the difference in refractive index between the adhesive layer 3 and an adherend (e.g., a liquid crystal cell). If the difference in refractive index is small, reflection of light at the interface between the pressure-sensitive adhesive layer 3 and the adherend is suppressed, and visibility of the liquid crystal display device can be improved.

Examples of the aromatic ring-containing (meth) acrylate include: (meth) acrylates containing a benzene ring such as benzyl (meth) acrylate, phenyl (meth) acrylate, o-phenylphenol (meth) acrylate, phenoxy ester (meth) acrylate, phenoxyethyl (meth) acrylate, phenoxypropyl (meth) acrylate, phenoxydiethylene glycol (meth) acrylate, ethylene oxide-modified nonylphenol (meth) acrylate, ethylene oxide-modified cresol (meth) acrylate, phenol ethylene oxide-modified (meth) acrylate, 2-hydroxy-3-phenoxypropyl (meth) acrylate, methoxybenzyl (meth) acrylate, chlorobenzyl (meth) acrylate, methylphenyl (meth) acrylate, and styrene (meth) acrylate; (meth) acrylates containing a naphthalene ring such as hydroxyethylated β -naphthol acrylate, 2-naphthylethyl (meth) acrylate, 2-naphthyloxyethyl acrylate, and 2- (4-methoxy-1-naphthyloxy) ethyl (meth) acrylate; biphenyl (meth) acrylate and other biphenyl ring-containing (meth) acrylates. Of these, benzyl (meth) acrylate and phenoxyethyl (meth) acrylate are preferable from the viewpoint of improving the adhesive properties and durability of the adhesive layer 3.

When the refractive index of the pressure-sensitive adhesive layer 3 is adjusted by the aromatic ring-containing (meth) acrylate, the content of the structural unit derived from the aromatic ring-containing (meth) acrylate in all the constituent units of the (meth) acrylic polymer is preferably 3 to 25 wt%. The content is more preferably 22 wt% or less, and still more preferably 20 wt% or less. The content is more preferably 8 wt% or more, and still more preferably 12 wt% or more. When the content of the structural unit derived from the aromatic ring-containing (meth) acrylate is 25 wt% or less, light leakage of the liquid crystal display device due to shrinkage of the optical film 1 can be suppressed, and the reworkability of the pressure-sensitive adhesive layer 3 tends to be improved. When the content is 3 wt% or more, light leakage of the liquid crystal display device tends to be sufficiently suppressed.

From the viewpoint of improving adhesiveness and heat resistance, the (meth) acrylic polymer may have 1 or more kinds of structural units derived from a comonomer having an unsaturated double bond-containing polymerizable functional group such as a (meth) acryloyl group and a vinyl group, in addition to the structural units derived from the aromatic ring-containing (meth) acrylate. Examples of such comonomers include: hydroxyl group-containing monomers such as 2-hydroxyethyl (meth) acrylate, 3-hydroxypropyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, 6-hydroxyhexyl (meth) acrylate, 8-hydroxyoctyl (meth) acrylate, 10-hydroxydecyl (meth) acrylate, 12-hydroxylauryl (meth) acrylate, and (4-hydroxymethylcyclohexyl) methyl acrylate; carboxyl group-containing monomers such as (meth) acrylic acid, carboxyethyl (meth) acrylate, carboxypentyl (meth) acrylate, itaconic acid, maleic acid, fumaric acid, and crotonic acid; acid anhydride group-containing monomers such as maleic anhydride and itaconic anhydride; caprolactone adducts of acrylic acid; sulfonic acid group-containing monomers such as styrenesulfonic acid, allylsulfonic acid, 2- (meth) acrylamide-2-methylpropanesulfonic acid, (meth) acrylamidopropanesulfonic acid, (meth) acrylic acid propyl sulfonate, and (meth) acryloyloxynaphthalenesulfonic acid; phosphoric acid group-containing monomers such as 2-hydroxyethyl acryloyl phosphate, and the like.

As the above-mentioned comonomers, there may be mentioned, for example: (N-substituted) amide monomers such as (meth) acrylamide, N-dimethyl (meth) acrylamide, N-butyl (meth) acrylamide, N-methylol (meth) acrylamide and N-methylol propane (meth) acrylamide; alkylaminoalkyl (meth) acrylate monomers such as aminoethyl (meth) acrylate, N-dimethylaminoethyl (meth) acrylate, and t-butylaminoethyl (meth) acrylate; alkoxyalkyl (meth) acrylate monomers such as methoxyethyl (meth) acrylate and ethoxyethyl (meth) acrylate; succinimide monomers such as N- (meth) acryloyloxymethylene succinimide, N- (meth) acryloyl-6-oxohexamethylene succinimide, and N- (meth) acryloyl-8-oxooctamethylene succinimide; morpholine monomers such as N-acryloylmorpholine; maleimide monomers such as N-cyclohexylmaleimide, N-isopropylmaleimide, N-laurylmaleimide and N-phenylmaleimide; n-methylitaconimide, N-ethylitaconimide, N-butylitaconimide, N-octylitaconimide, N-2-ethylhexyl itaconimide, N-cyclohexylitaconimide, N-lauryl itaconimide, etc.

As the above-mentioned comonomers, there may be mentioned, for example: vinyl acetate, vinyl propionate, N-vinylpyrrolidone, methylvinylpyrrolidone, vinylpyridine, vinylpiperidone, vinylpyrimidine, vinylpiperazine, vinylpyrazine, vinylpyrrole, vinylimidazole, vinyl

Vinyl monomers such as oxazole, vinyl morpholine, N-vinylcarboxylic acid amides, styrene, alpha-methylstyrene, and N-vinylcaprolactam; cyanoacrylate monomers such as acrylonitrile and methacrylonitrile; epoxy group-containing acrylic monomers such as glycidyl (meth) acrylate; polyethylene glycol (meth) acrylate and (meth) acrylic acidGlycol acrylate monomers such as polypropylene glycol acid ester, methoxyethylene glycol (meth) acrylate, and methoxypolypropylene glycol (meth) acrylate; acrylic ester monomers such as tetrahydrofurfuryl (meth) acrylate, fluorine-containing (meth) acrylate, silicone (meth) acrylate, and 2-methoxyethyl acrylate. Further, as the comonomer, for example: olefin monomers such as isoprene, butadiene, and isobutylene; vinyl ethers and the like.

Examples of the above-mentioned comonomers include: silane monomers such as 3-acryloxypropyltriethoxysilane, vinyltrimethoxysilane, vinyltriethoxysilane, 4-vinylbutyltrimethoxysilane, 4-vinylbutyltriethoxysilane, 8-vinyloctyltrimethoxysilane, 8-vinyloctyltriethoxysilane, 10-methacryloxydecyltrimethoxysilane, 10-acryloxydecyltrimethoxysilane, 10-methacryloxydecyltriethoxysilane, and 10-acryloxydecyltriethoxysilane.

As the above-mentioned comonomers, for example: esterified products of (meth) acrylic acid and polyhydric alcohols (polyfunctional monomers having 2 or more unsaturated double bonds such as (meth) acryloyl groups and vinyl groups) such as tripropylene glycol di (meth) acrylate, tetraethylene glycol di (meth) acrylate, 1, 6-hexanediol di (meth) acrylate, bisphenol a diglycidyl ether di (meth) acrylate, neopentyl glycol di (meth) acrylate, trimethylolpropane tri (meth) acrylate, pentaerythritol tetra (meth) acrylate, dipentaerythritol penta (meth) acrylate, dipentaerythritol hexa (meth) acrylate, and caprolactone-modified dipentaerythritol hexa (meth) acrylate; and compounds obtained by adding 2 or more compounds having an unsaturated double bond such as a (meth) acryloyl group or a vinyl group to a backbone such as polyester, epoxy, urethane, and the like (for example, polyester (meth) acrylate, epoxy (meth) acrylate, urethane (meth) acrylate), and the like.

The content of the structural unit derived from the comonomer in the (meth) acrylic polymer is not particularly limited, and is, for example, 0 to 20 wt%, preferably 0.1 to 15 wt%, and more preferably 0.1 to 10 wt%.

As the comonomer, a hydroxyl group-containing monomer and a carboxyl group-containing monomer are preferable from the viewpoint of adhesiveness and durability. As the comonomer, a hydroxyl group-containing monomer and a carboxyl group-containing monomer may be used in combination. For example, when the pressure-sensitive adhesive composition for forming the pressure-sensitive adhesive layer 3 contains a crosslinking agent, the comonomer functions as a reaction point with the crosslinking agent. Since the hydroxyl group-containing monomer, carboxyl group-containing monomer, or the like has excellent reactivity with an intermolecular crosslinking agent, it is suitable for improving the cohesive property and heat resistance of the pressure-sensitive adhesive layer 3 to be obtained. In particular, the hydroxyl group-containing monomer is suitable for improving the reworkability of the adhesive layer 3. The carboxyl group-containing monomer is suitable for achieving both durability and reworkability of the adhesive layer 3.

When a hydroxyl group-containing monomer is used as a comonomer, the content of the structural unit derived from the hydroxyl group-containing monomer in the (meth) acrylic polymer is preferably 0.01 to 15 wt%, more preferably 0.03 to 10 wt%, and still more preferably 0.05 to 7 wt%. When a carboxyl group-containing monomer is used as a comonomer, the content of the structural unit derived from the carboxyl group-containing monomer in the (meth) acrylic polymer is preferably 0.05 to 10% by weight, more preferably 0.1 to 8% by weight, and still more preferably 0.2 to 6% by weight.

The weight average molecular weight of the (meth) acrylic polymer is, for example, 50 to 300 ten thousand, and from the viewpoint of durability, particularly heat resistance, it is preferably 70 to 270 ten thousand, and more preferably 80 to 250 ten thousand. When the weight average molecular weight of the (meth) acrylic polymer is 50 ten thousand or more, the pressure-sensitive adhesive layer 3 tends to have heat resistance sufficient for practical use. When the weight average molecular weight of the (meth) acrylic polymer is 300 ten thousand or less, the viscosity of the coating liquid for producing the pressure-sensitive adhesive layer 3 tends to be easily adjusted. If the viscosity of the coating liquid can be easily adjusted, it is not necessary to add a large amount of a diluting solvent to the coating liquid, and therefore, the production cost of the pressure-sensitive adhesive layer 3 can be suppressed. In the present specification, the weight average molecular weight refers to a value obtained by converting polystyrene based on the measurement result of GPC (gel permeation chromatography),

The (meth) acrylic polymer can be produced by a known polymerization reaction such as solution polymerization, bulk polymerization, emulsion polymerization, and various radical polymerizations. The (meth) acrylic polymer may be a random copolymer, a block copolymer, or a graft copolymer.

The adhesive contained in the adhesive layer 3 may have a structure in which the base polymer is crosslinked by a crosslinking agent. For example, in the case of using a (meth) acrylic polymer as a base polymer, an organic crosslinking agent or a polyfunctional metal chelate compound may be used as the crosslinking agent. Examples of the organic crosslinking agent include: isocyanate crosslinking agents, peroxide crosslinking agents, epoxy crosslinking agents, imine crosslinking agents, and the like. The polyfunctional metal chelate compound is a chelate compound in which a polyvalent metal is covalently bonded or coordinately bonded to an organic compound. Examples of the atom constituting the polyvalent metal include: al, Cr, Zr, Co, Cu, Fe, Ni, V, Zn, In, Ca, Mg, Mn, Y, Ce, Sr, Ba, Mo, La, Sn, Ti, etc. The organic compound contained in the polyfunctional metal chelate compound contains, for example, an oxygen atom or the like. Examples of the organic compound include: alkyl esters, alcohol compounds, carboxylic acid compounds, ether compounds, ketone compounds, and the like.

The amount of the crosslinking agent used in the binder is preferably 3 parts by weight or less, more preferably 0.01 to 3 parts by weight, still more preferably 0.02 to 2 parts by weight, and particularly preferably 0.03 to 1 part by weight, based on 100 parts by weight of the (meth) acrylic polymer.

The adhesive layer 3 may further contain other materials than adhesives. Examples of the other materials include: conductive materials, silane coupling agents, and other additives. The conductive material is suitable for reducing the surface resistivity of the adhesive layer 3 to prevent display defects caused by electrification of the liquid crystal display device. As the conductive material, the conductive material described above in the description of the antistatic layer 2 can be cited. The conductive material contained in the pressure-sensitive adhesive layer 3 is preferably an ionic compound from the viewpoint of compatibility with the base polymer and transparency of the pressure-sensitive adhesive layer 3. In particular, when the pressure-sensitive adhesive layer 3 contains an acrylic pressure-sensitive adhesive containing a (meth) acrylic polymer as a base polymer, an ionic compound is preferably used as the conductive material. From the viewpoint of antistatic properties, the ionic compound is preferably an ionic liquid.

The adhesive layer 3 preferably contains 0.05 to 20 parts by weight of a conductive material (e.g., an ionic compound) with respect to 100 parts by weight of a base polymer (e.g., a (meth) acrylic polymer) of the adhesive. When the pressure-sensitive adhesive layer 3 contains 0.05 parts by weight or more of the conductive material, the surface resistivity of the pressure-sensitive adhesive layer 3 tends to be sufficiently reduced, and the antistatic performance of the pressure-sensitive adhesive layer 3 tends to be sufficiently improved. The adhesive layer 3 preferably contains the conductive material in an amount of 0.1 part by weight or more, more preferably 0.5 part by weight or more, per 100 parts by weight of the base polymer of the adhesive. From the viewpoint of imparting sufficient durability to the adhesive layer 3 for practical use, the adhesive layer 3 preferably contains 20 parts by weight or less, more preferably 10 parts by weight or less, of the conductive material per 100 parts by weight of the base polymer of the adhesive.

Examples of the other additives include polyether compounds such as polyalkylene glycols (for example, polypropylene glycol), colorants, pigments, dyes, surfactants, plasticizers, tackifiers, surface lubricants, leveling agents, softeners, antioxidants, light stabilizers, ultraviolet absorbers, polymerization inhibitors, inorganic fillers, organic fillers, and metal powders, which are used as appropriate depending on the intended use. The additive may be in the form of powder, particles or foil. The additive may be a redox-type additive by using a reducing agent in a controllable range. The adhesive layer 3 preferably contains 5 parts by weight or less, more preferably 3 parts by weight or less, and still more preferably 1 part by weight or less of other additives, relative to 100 parts by weight of a base polymer (for example, a (meth) acrylic polymer) of the adhesive.

The thickness of the pressure-sensitive adhesive layer 3 is not particularly limited, and is, for example, 5 to 100 μm, preferably 10 to 50 μm.

The surface resistivity of the adhesive layer 3 is not particularly limitedAt most, less than 1.0X 10¹⁴Omega/□, preferably 1.0X 10¹²Omega/□ or less. The lower limit of the surface resistivity of the pressure-sensitive adhesive layer 3 is not particularly limited, and is, for example, 1.0 × 10 from the viewpoint of durability⁸Omega/□. The surface resistivity of the adhesive layer 3 can be measured by the same method as the surface resistivity of the antistatic layer 2.

[ method for producing optical film with pressure-sensitive adhesive layer ]

The optical film 10 with an adhesive layer can be produced, for example, by the following method. However, the method for manufacturing the optical film with an adhesive layer 10 is not limited to the following example.

A laminate of the optical film 1 and the antistatic layer 2 was obtained as described above. Next, a solution containing a binder was prepared. The solution is applied to the surface of a separator to obtain a coating film. The separator is not particularly limited, and for example, a polyethylene terephthalate film treated with a silicone-based release agent can be used. Next, the adhesive layer 3 is formed on the separator by drying the coating film. The pressure-sensitive adhesive layer 3 thus obtained is transferred onto the laminate, for example, the antistatic layer 2, to produce the pressure-sensitive adhesive layer-attached optical film 10.

(liquid Crystal Panel)

Fig. 5 shows a liquid crystal panel 100 of the present embodiment. The liquid crystal panel 100 of fig. 5 includes an optical film 10 with an adhesive layer and a liquid crystal cell 20. The liquid crystal cell 20 includes a liquid crystal layer 21, a 1 st transparent substrate 22, and a 2 nd transparent substrate 23. The liquid crystal layer 21 is disposed between the 1 st transparent substrate 22 and the 2 nd transparent substrate 23, and is in contact with the 1 st transparent substrate 22 and the 2 nd transparent substrate 23, respectively. A conductive layer (further conductive layer) typified by an ITO layer is not provided between the optical film 10 with an adhesive layer and the liquid crystal cell 20. The optical film 10 with an adhesive layer is directly in contact with the transparent substrate (1 st transparent substrate 22) on the viewing side in the liquid crystal cell 20 via the adhesive layer 3. In other words, the optical film 10 with an adhesive layer is in contact with the liquid crystal cell 20 without sandwiching an ITO layer. However, the liquid crystal panel of the present invention is not limited to the example of fig. 5 as long as it includes the optical film 10 with an adhesive layer and the liquid crystal cell 20, the liquid crystal cell 20 includes a pair of transparent substrates and a liquid crystal layer disposed between the pair of transparent substrates, and no conductive layer is provided between the optical film 10 with an adhesive layer and the liquid crystal cell 20. For example, the liquid crystal layer 21 in the liquid crystal cell 20 may not be directly in contact with the 1 st transparent substrate 22 and/or the 2 nd transparent substrate 23.

The liquid crystal layer 21 contains liquid crystal molecules that are uniformly aligned in the absence of an electric field, for example. The liquid crystal layer 21 including such liquid crystal molecules is suitable for an IPS (In-Plane-Switching) mode. However, the liquid crystal layer 21 may also be used for a TN (Twisted Nematic) type, an STN (Super Twisted Nematic) type, a pi type, a VA (Vertical Alignment) type, or the like. The thickness of the liquid crystal layer 21 is, for example, 1.5 to 4 μm.

Examples of the material of the 1 st transparent substrate 22 and the 2 nd transparent substrate 23 include: glass and polymers. In this specification, a transparent substrate made of a polymer is sometimes referred to as a polymer film. Examples of the polymer constituting the transparent substrate include: polyethylene terephthalate, polycycloolefins, polycarbonates, and the like. The thickness of the transparent substrate made of glass is, for example, 0.1mm to 1 mm. The thickness of the transparent substrate made of a polymer is, for example, 10 to 200 μm.

The liquid crystal cell 20 may further include other layers than the liquid crystal layer 21, the 1 st transparent substrate 22, and the 2 nd transparent substrate 23. Examples of the other layers include: color filter, easy-to-adhere layer and hard coating layer. The color filter is disposed, for example, on the visible side of the liquid crystal layer 21, and is preferably located between the 1 st transparent substrate 22 and the pressure-sensitive adhesive layer 3 of the optical film 10 with a pressure-sensitive adhesive layer. The easy adhesion layer and the hard coat layer are disposed on the surface of the 1 st transparent substrate 22 or the 2 nd transparent substrate 23, for example.

The liquid crystal panel 100 may further include a conductive structure (not shown) electrically connected to the side surface of the antistatic layer 2. The conductive structure may be grounded, and the optical film 10 with the adhesive layer may be further inhibited from being electrostatically charged. The conduction structure can cover the whole side of antistatic layer 2, also can partially cover the side of antistatic layer 2. The ratio of the area of the side surface of the antistatic layer 2 covered with the conductive structure to the area of the entire side surface of the antistatic layer 2 is, for example, 1% or more, preferably 3% or more. The conductive structure may be electrically connected not only to the side of the antistatic layer 2 but also to the side of the optical film 1 and the adhesive layer 3.

Examples of the material of the conductive structure include: a conductive paste made of a metal such as silver or gold; a conductive adhesive; other conductive materials. The conducting structure may be a wiring protruding from the side of the antistatic layer 2.

The liquid crystal panel 100 may further include other optical films than the optical film 1. Other examples of the optical film are the same as those of the optical film 1.

In the case where the other optical film is a polarizing plate, the polarizing plate is attached to the 2 nd transparent substrate 23 of the liquid crystal cell 20 via an adhesive layer, for example. The polarizing plate may have, for example, the constitution described above for the polarizing plate 4. In the polarizing plate as another optical film, the transmission axis (or absorption axis) of the polarizer is orthogonal to, for example, the transmission axis (or absorption axis) of the polarizer in the polarizing plate 4. As a material of the adhesive layer for bonding the polarizing plate and the 2 nd transparent substrate 23 together, the materials described above for the adhesive layer 3 can be used. The thickness of the adhesive layer is not particularly limited, but is, for example, 1 to 100. mu.m, preferably 2 to 50 μm, more preferably 2 to 40 μm, and still more preferably 5 to 35 μm.

The liquid crystal panel 100 is suitable for applications that do not require a touch sensor, such as a cluster of instrument panels for vehicles and a mirror display. The cluster of the dashboard is a panel that displays the running speed, the engine speed, and the like of the vehicle.

The effect of the present invention is more remarkable as the reflectance of the liquid crystal panel 100 to external light is lower. The light reflectance Y of the liquid crystal panel 100 is, for example, 8.0% or less, and may be 7.0% or less, 6.0% or less, 5.0% or less, 4.0% or less, 3.0% or less, 2.0% or less, 1.5% or less, 1.3% or less, and further 1.1% or less. The lower limit of the light reflectance Y is, for example, 0.01% or more. The liquid crystal panel 100 having the light reflectance Y of 1.5% or less, preferably 1.3% or less is suitable for applications requiring good visibility, for example, a vehicle-mounted display. The light reflectance Y of the liquid crystal panel 100 can be measured in the same manner as the light reflectance Y of the optical film 10 with an adhesive layer.

The liquid crystal panel of the present invention may have other layers and/or members than the above-described layers and/or members.

(modification of liquid Crystal Panel)

The liquid crystal panel 100 of fig. 5 may further include a touch sensor or a touch panel. Fig. 6 shows a liquid crystal panel 110 provided with the touch panel 30. The structure of the liquid crystal panel 110 is the same as that of the liquid crystal panel 100 except for the touch panel 30. Therefore, the same reference numerals are given to the common elements in the liquid crystal panel 100 and the liquid crystal panel 110, and the description thereof may be omitted.

In the liquid crystal panel 110, the touch panel 30 is disposed on the visible side of the optical film 1, for example. The touch panel 30 is not in contact with the optical film 10 with an adhesive layer, and a gap (air layer) is formed between the touch panel 30 and the optical film 10 with an adhesive layer. The liquid crystal panel 110 is a so-called Out-cell (Out-cell) type liquid crystal panel. The touch panel 30 may be of an optical type, an ultrasonic type, a capacitance type, a resistance film type, or the like. When the touch panel 30 is of a resistive film type, the touch panel 30 has a structure in which, for example, 2 electrode plates having a transparent conductive film are arranged to face each other with spacers interposed therebetween. When the touch panel 30 is of the capacitance type, the touch panel 30 is formed of, for example, a transparent conductive film including a transparent conductive thin film having a predetermined pattern shape.

(embodiment of liquid Crystal display device)

The liquid crystal display device of the present embodiment includes, for example, a liquid crystal panel 100 and an illumination system. In the liquid crystal display device, the liquid crystal panel 110 described with reference to fig. 6 may be used instead of the liquid crystal panel 100. In the liquid crystal display device, the liquid crystal panel 100 is disposed on the visible side of the illumination system, for example. The illumination system has, for example, a backlight or a reflector, and irradiates the liquid crystal panel 100 with light.

Examples

The present invention will be described in more detail below with reference to examples. The present invention is not limited to the embodiments described below. In the following description, "%" represents "wt%" and "parts" represents "parts by weight", unless otherwise specified. Unless otherwise specified, the temperature and humidity in the room were 23 ℃ and 65% RH.

< (meth) acrylic polymer weight average molecular weight >

The weight average molecular weight (Mw) of the (meth) acrylic polymer used in the adhesive layer was measured by GPC (gel permeation chromatography). The Mw/Mn of the (meth) acrylic polymer was also measured in the same manner.

An analysis device: HLC-8120GPC, manufactured by Tosoh corporation

Column chromatography: G7000H, manufactured by Tosoh corporation_XL+GMH_XL+GMH_XL

Column size: each one of

Meter 90cm

Column temperature: 40 deg.C

Flow rate: 0.8mL/min

Injection amount: 100 μ L

Eluent: tetrahydrofuran (THF)

The detector: differential Refractometer (RI)

Standard sample: polystyrene

< adhesive layer A >

A four-necked flask equipped with a stirrer, a thermometer, a nitrogen inlet, and a condenser was charged with 76.9 parts of butyl acrylate, 18 parts of benzyl acrylate, 5 parts of acrylic acid, and 0.1 part of 4-hydroxybutyl acrylate to obtain a monomer mixture. Further, 0.1 part of 2, 2' -azobisisobutyronitrile as a polymerization initiator was added together with 100 parts of ethyl acetate with respect to 100 parts of the monomer mixture (solid component). While the mixture was slowly stirred, nitrogen gas was introduced into the flask and replaced with nitrogen gas. The polymerization reaction was carried out for 8 hours while maintaining the liquid temperature in the flask at around 55 ℃, thereby preparing a solution of an acrylic polymer having a weight average molecular weight (Mw) of 200 ten thousand and a Mw/Mn of 4.1.

Then, an isocyanate crosslinking agent (Coronate L, trimethylolpropane toluene diisocyanate, manufactured by tokyo corporation) was further added in an amount of 0.45 part, a peroxide crosslinking agent (NYPER BMT, manufactured by japan fat and oil co., ltd.) 0.1 part, and a silane coupling agent (KBM-403, γ -glycidoxypropylmethoxysilane, manufactured by shin-Etsu chemical industries, ltd.) 0.2 part, based on 100 parts of the solid content of the acrylic polymer solution, to prepare a solution of the acrylic pressure-sensitive adhesive composition.

Next, the obtained solution was coated on one surface of a separator (MRF 38 manufactured by mitsubishi chemical polyester film co. The separator is a polyethylene terephthalate film treated with a silicone-based release agent. The obtained coating film was dried at 155 ℃ for 1 minute, and thereby a pressure-sensitive adhesive layer a was formed on the surface of the separator. The thickness of the adhesive layer A was 20 μm.

< adhesive layer B >

A solution of an acrylic polymer having a weight average molecular weight (Mw) of 210 ten thousand and an Mw/Mn of 4.0 was prepared in the same manner as in the pressure-sensitive adhesive layer a except that 94.9 parts of butyl acrylate, 5 parts of acrylic acid and 0.1 part of 4-hydroxybutyl acrylate were charged into a four-necked flask.

Next, a solution of an acrylic pressure-sensitive adhesive composition was prepared in the same manner as the pressure-sensitive adhesive layer a except that the prepared solution of the acrylic polymer was used, and the solution was further applied to one surface of the separator and dried to form a pressure-sensitive adhesive layer B. The thickness of the adhesive layer B was 12 μm.

< anti-reflection layer AR1 >

A cellulose Triacetate (TAC) film having an antiglare layer formed on the surface thereof was prepared. The TAC film was introduced into a roll-to-roll sputtering film forming apparatus, and the surface of the antiglare layer was subjected to bombardment treatment (plasma treatment with Ar gas) by running the film. Next, SiO as an adhesion layer having a physical film thickness of 5nm was formed on the surface of the antiglare layer_xLayer (x < 2). Then, Nb with a physical film thickness of 13nm was sequentially formed on the adhesion layer₂O₅Layer (No. 1 high refractive index layer), SiO with a physical film thickness of 30nm₂Layer (No. 1 low refractive index layer), Nb with a physical film thickness of 100nm₂O₅Layer (2 nd high refractive index layer) and SiO with a physical film thickness of 85nm₂Layer (2 nd low refractive index layer), laminate a was produced. When these oxide films were formed, the amount of oxygen introduced was adjusted by plasma glow discharge monitoring (PEM) control while the pressure in the apparatus was kept constant by adjusting the amount of argon gas introduced and the amount of exhaust gas.

Next, the 2 nd low refractive index layer (SiO) of the laminate a was formed₂Layer) as an antifouling layer, a layer made of a fluorine-based resin (physical film thickness: 9 nm). The adhesive layer B was further transferred to the surface of the TAC film of the laminate a, thereby producing an antireflection layer AR1 with an adhesive layer.

< polarizing plate P1 >

First, an acrylic film was produced by the following method. 8000g of Methyl Methacrylate (MMA), 2000g of methyl 2- (hydroxymethyl) acrylate (MHMA), 10000g of 4-methyl-2-pentanone (methyl isobutyl ketone, MIBK), and 5g of n-dodecyl mercaptan were charged in a 30-liter tank reactor equipped with a stirrer, a temperature sensor, a condenser, and a nitrogen gas inlet tube. The mixture in the reactor was heated to 105 ℃ and refluxed while introducing nitrogen gas into the reactor. Next, 5.0g of t-butyl peroxyisopropyl carbonate (Kayakarun BIC-7, Kayaku Akzo Co., Ltd.) was added as a polymerization initiator, and a solution of 10.0g of t-butyl peroxyisopropyl carbonate and 230g of MIBK was added dropwise thereto over 4 hours, to carry out solution polymerization. The solution polymerization is carried out under reflux at about 105 to 120 ℃. After the solution was added dropwise, the mixture was aged for a further 4 hours.

Then, 30g of a stearyl phosphate/distearyl phosphate mixture (Phoslex A-18, manufactured by Sakai Chemical Industry) was added to the obtained polymer solution, and a cyclized condensation reaction was carried out at about 90 to 120 ℃ for 5 hours under reflux. Then, the resulting solution was introduced at a processing speed of 2.0 kg/hr in terms of resin amount into an exhaust type twin screw having a cylinder temperature of 260 ℃, a rotational speed of 100rpm, a reduced pressure of 13.3 to 400hPa (10 to 300mmHg), a number of rear exhaust holes of 1 and a number of front exhaust holes of 4Rod extruder (

L/D ═ 30). Further cyclized condensation reaction and devolatilization are carried out in an extruder. Thus, transparent particles of the lactone ring-containing polymer were obtained.

The lactone ring-containing polymer thus obtained was subjected to dynamic TG measurement, and as a result, a mass decrease of 0.17 mass% was detected. The lactone ring-containing polymer had a weight-average molecular weight (Mw) of 133000, a melt flow rate of 6.5g/10 min and a glass transition temperature of 131 ℃.

Using a single screw extruder (screw)

) The obtained pellets were kneaded and extruded with acrylonitrile-styrene (AS) resin (Toyo AS20, manufactured by toyoyo styrene co., ltd.) at a mass ratio of 90/10 to obtain transparent pellets. The glass transition temperature of the resulting particles was 127 ℃.

Use of

The pellets were melt-extruded from a hanger type T-die having a width of 400mm by means of a single screw extruder to prepare a film having a thickness of 120 μm. The film was stretched to 2.0 times in the machine direction and 2.0 times in the cross direction at a temperature of 150 ℃ using a biaxial stretching machine, to obtain a stretched film (acrylic film) having a thickness of 30 μm. The optical properties of the stretched film were measured, and as a result, the total light transmittance was 93%, the in-plane retardation Δ nd was 0.8nm, and the thickness direction retardation Rth was 1.5 nm.

Next, a polarizing plate P1 was produced by the following method. First, a polyvinyl alcohol film having a thickness of 45 μm was dyed in an iodine solution (temperature 30 ℃) having a concentration of 0.3% for 1 minute between a plurality of rolls having different speed ratios, and stretched to a draw ratio of 3. Next, the obtained stretched film was immersed in an aqueous solution (temperature 60 ℃) containing 4% boric acid and 10% potassium iodide for 0.5 minute, and stretched until the total stretching ratio became 6 times. Subsequently, the stretched film was immersed in an aqueous solution (temperature 30 ℃) containing potassium iodide at a concentration of 1.5% for 10 seconds, and washed. Next, the stretched film was dried at 50 ℃ for 4 minutes to obtain a polarizer having a thickness of 18 μm. A TAC film (trade name "KC 4 UY" manufactured by Konika Mingda) having a thickness of 40 μm was bonded to one main surface of the polarizer obtained using a polyvinyl alcohol adhesive. The acrylic film having a thickness of 30 μm was bonded to the other principal surface of the polarizer with a polyvinyl alcohol adhesive. Thereby, a polarizing plate P1 was obtained.

< antistatic layer AE1 >

An aqueous dispersion (trade name "Clevious P" manufactured by Heraeus) containing PEDOT (poly (3, 4-methylenedioxythiophene)) and PSS (polystyrenesulfonic acid) was neutralized with 28% aqueous ammonia (manufactured by Tokyo chemical Co., Ltd.) to a solid fraction of 1%, and the resulting mixture (hereinafter referred to as "PEDOT-PSS-NH") was added₄") 6.9 parts with respect to PEDOT-PSS-NH ₄100 parts of 233 parts and 83 parts of polyurethane resin (SUPERFLEX 210 manufactured by first Industrial pharmaceutical Co., Ltd., solid content concentration: 35%) as a binder, and a binder

Oxazoline-based Polymer (EPOCROS WS700 manufactured by Nippon catalyst Co., Ltd., solid content concentration: 25%) to PEDOT-PSS-NH ₄100 parts of 17 parts of polyether-modified siloxane (KF-6017 manufactured by shin-koku corporation) as a leveling agent, 2.8 parts of N-methylpyrrolidone as a conductive assistant, and a mixed solvent containing 18.5 parts of water and 71.1 parts of isopropyl alcohol (IPA) were mixed to prepare a coating solution having a solid content concentration of 0.30%. Next, the coating liquid was applied to one surface of the polarizing plate P1. The resultant coating film was dried at 80 ℃ for 1 minute, whereby an antistatic layer AE1 was formed. Thus, a laminate composed of the polarizing plate P1 and the antistatic layer AE1 was obtained. The thickness of the antistatic layer AE1 was 20 nm.

< antistatic layer AE2 >

Reacting PEDOT-PSS-NH₄The amounts of N-methylpyrrolidone, water and IPA were changed to 14.6 parts, 2.5 parts, 16.5 parts and 63.5 parts, respectively, and the contents were adjusted to

The amount of the oxazoline-based polymer mixed is changed relative to PEDOT-PSS-NH₄An antistatic layer AE2 was formed in the same manner as the antistatic layer AE1 except that a coating solution having a solid content concentration of 1.00% was prepared in 333 parts. Thus, a laminate composed of the polarizing plate P1 and the antistatic layer AE2 was obtained. The thickness of the antistatic layer AE2 was 70 nm.

< antistatic layer AE3 >

Reacting PEDOT-PSS-NH₄The amounts of N-methylpyrrolidone, water and IPA were changed to 35.1 parts, 1.9 parts, 12.5 parts and 48.1 parts, respectively, and the contents were adjusted to

The blending amounts of oxazoline-based polymer and polyether-modified siloxane were changed to PEDOT-PSS-NH, respectively₄Antistatic layer AE3 was formed in the same manner as antistatic layer AE1 except that coating solutions having a solid content concentration of 1.20% were prepared for 0 parts and 8.3 parts. Thus, a laminate composed of the polarizing plate P1 and the antistatic layer AE3 was obtained. The thickness of the antistatic layer AE3 was 80 nm.

< antistatic layer AE4 >

Reacting PEDOT-PSS-NH₄The amounts of N-methylpyrrolidone, water and IPA were changed to 23.4 parts, 2.3 parts, 57.8 parts and 15.0 parts, respectively, and the contents were adjusted to

The blending amounts of oxazoline-based polymer and polyether-modified siloxane were changed to PEDOT-PSS-NH, respectively₄Antistatic layer AE4 was formed in the same manner as antistatic layer AE1 except that coating solutions having a solid content concentration of 0.80% were prepared for 0 parts and 8.3 parts. Thus, a laminate composed of the polarizing plate P1 and the antistatic layer AE4 was obtained. The thickness of the antistatic layer AE4 was 50 nm.

< antistatic layer AE5 >

As the aqueous dispersion containing PEDOT and PSS, a commercial name "Clevious PH 1000" manufactured by Heraeus was used,simultaneously, PEDOT-PSS-NH obtained by the aqueous dispersion is₄And the mixing amounts of N-methylpyrrolidone, water and IPA were changed to 43.9 parts, 1.6 parts, 40.9 parts and 10.6 parts, respectively, and the contents were adjusted to

The blending amounts of oxazoline-based polymer and polyether-modified siloxane were changed to PEDOT-PSS-NH, respectively₄Antistatic layer AE5 was formed in the same manner as antistatic layer AE1 except that coating solutions having a solid content concentration of 1.50% were prepared for 0 parts and 8.3 parts. Thus, a laminate composed of the polarizing plate P1 and the antistatic layer AE5 was obtained. The thickness of the antistatic layer AE5 was 100 nm.

< antistatic layer AE6 >

Polyether modified siloxane as leveling agent is not used, and PEDOT-PSS-NH₄The amounts of N-methylpyrrolidone, water and IPA were changed to 24.0 parts, 2.2 parts, 14.9 parts and 57.3 parts, respectively, and the contents were adjusted to

The amount of the oxazoline-based polymer mixed is changed relative to PEDOT-PSS-NH₄An antistatic layer AE6 was formed in the same manner as the antistatic layer AE1 except that a coating liquid having a solid content concentration of 0.80% was prepared for 0 part. Thus, a laminate composed of the polarizing plate P1 and the antistatic layer AE6 was obtained. The thickness of the antistatic layer AE6 was 50 nm.

< antistatic layer AE7 >

PEDOT-PSS-NH without using polyether modified siloxane as leveling agent and N-methyl pyrrolidone as conductive auxiliary agent₄The amounts of water and IPA were changed to 6.0 parts, 84.2 parts and 9.4 parts, respectively, and the contents were adjusted to

The amount of the oxazoline-based polymer mixed is changed relative to PEDOT-PSS-NH₄An antistatic layer AE7 was formed in the same manner as the antistatic layer AE1 except that a coating solution having a solid content concentration of 0.20% was prepared as 0 part. Thus, a polarizing plate P1 and an antistatic film were obtainedAnd a laminate comprising an electrical layer AE 7. The thickness of the antistatic layer AE7 was 10 nm.

< antistatic layer AE8 >

PEDOT-PSS-NH without the use of N-methylpyrrolidone as a conductive aid₄The amounts of water and IPA were changed to 23.4 parts, 60.0 parts and 15.0 parts, respectively, and the contents were adjusted to

The amount of the oxazoline-based polymer mixed is changed relative to PEDOT-PSS-NH₄An antistatic layer AE8 was formed in the same manner as the antistatic layer AE1 except that a coating solution having a solid content concentration of 0.80% was prepared as 0 part. Thus, a laminate composed of the polarizing plate P1 and the antistatic layer AE8 was obtained. The thickness of the antistatic layer AE8 was 50 nm.

The compositions of the coating liquids for forming antistatic layers AE1 to AE8 are summarized in table 1 below.

[ Table 1]

The content of the adhesive and the leveling agent is expressed by the parts of PEDOT-PSS-NH 4100 parts

(example 1)

The antireflection layer AR1 with an adhesive layer was joined to the polarizing plate P1 side of the laminate composed of the polarizing plate P1 and the antistatic layer AE 1. The bonding is performed by the adhesive layer of the antireflection layer AR 1. Next, the adhesive layer a was transferred onto the antistatic layer AE1, and the optical film with an adhesive layer of example 1 was obtained.

(example 2)

An optical film with a pressure-sensitive adhesive layer of example 2 was obtained in the same manner as in example 1, except that a laminate composed of a polarizing plate P1 and an antistatic layer AE2 was used.

(example 3)

An optical film with a pressure-sensitive adhesive layer of example 3 was obtained in the same manner as in example 1, except that a laminate composed of a polarizing plate P1 and an antistatic layer AE3 was used.

(example 4)

An optical film with a pressure-sensitive adhesive layer of example 4 was obtained in the same manner as in example 1, except that a laminate composed of a polarizing plate P1 and an antistatic layer AE4 was used.

(example 5)

The pressure-sensitive adhesive layer a was transferred onto the antistatic layer AE4 of the laminate composed of the polarizing plate P1 and the antistatic layer AE4 without using the anti-reflection layer AR1 with a pressure-sensitive adhesive layer, to obtain the pressure-sensitive adhesive layer-attached optical film of example 5.

(example 6)

An optical film with a pressure-sensitive adhesive layer of example 6 was obtained in the same manner as in example 1, except that a laminate composed of a polarizing plate P1 and an antistatic layer AE5 was used.

Comparative example 1

An optical film with a pressure-sensitive adhesive layer of comparative example 1 was obtained in the same manner as in example 1, except that a laminate composed of a polarizing plate P1 and an antistatic layer AE6 was used.

Comparative example 2

An optical film with a pressure-sensitive adhesive layer of comparative example 2 was obtained in the same manner as in example 1, except that a laminate composed of a polarizing plate P1 and an antistatic layer AE7 was used.

Comparative example 3

An optical film with a pressure-sensitive adhesive layer of comparative example 3 was obtained in the same manner as in example 1, except that a laminate composed of a polarizing plate P1 and an antistatic layer AE8 was used.

Comparative example 4

The pressure-sensitive adhesive layer a was transferred onto the antistatic layer AE6 of the laminate composed of the polarizing plate P1 and the antistatic layer AE6 without using the anti-reflection layer AR1 with a pressure-sensitive adhesive layer, to obtain the pressure-sensitive adhesive layer-attached optical film of comparative example 4.

The following evaluations were made for examples and comparative examples.

< surface resistivity of antistatic layer >

The surface resistivity of the antistatic layer was measured using a laminate composed of a polarizing plate and the antistatic layer. The measurement was carried out using a resistivity meter (Hiresta-UP MCP-HT450 or Loresta-GP MCP-T600 manufactured by Mitsubishi Chemical Analyticech Co., Ltd.) according to the method prescribed in JIS K6911: 1995.

< Difference DeltaT >

The difference Δ T of the optical film with an adhesive layer was evaluated by the method described above. However, each measurement region was made to be a circle having a diameter of 16 μm when observed perpendicularly to the surface of the polarizing plate P1. The area of the measurement region on the surface was set to 100cm²The random positions in the range of (2) (a rectangle of 10cm × 10cm when viewed perpendicularly to the surface) are 30 in total. The distance between the measurement regions most distant from each other was 10 cm. The measurement apparatus used LVmicroZ2 manufactured by Lambda Vision corporation.

< light reflectance Y >

The light reflectance Y of the optical film with an adhesive layer was evaluated by the method described above. However, as an apparatus for measuring the tristimulus values, a spectrocolorimeter CM2600d manufactured by konica minolta co.

< light reflectance Y of liquid crystal panel

An optical film with an adhesive layer was bonded to a transparent substrate on the viewing side in a liquid crystal cell to produce a liquid crystal panel. The liquid crystal cell used has the same structure as the liquid crystal cell 20 of fig. 5. As reference examples 1 and 2, liquid crystal panels were produced in which the optical films with adhesive layers of comparative examples 1 and 4 were bonded to the ITO layer of the liquid crystal cell having an amorphous ITO layer (thickness 20nm) formed on the transparent substrate on the viewing side, respectively. In reference examples 1 and 2, the adhesive layer of the optical film with an adhesive layer was directly in contact with the ITO layer. The ITO layer was formed by sputtering. The Sn ratio of ITO contained in the ITO layer was 3%. The light reflectance Y of each of the liquid crystal panels produced was evaluated by the method described above. However, as an apparatus for measuring the tristimulus values, a spectrocolorimeter CM2600d manufactured by konica minolta co. In addition, the measurement was performed in the following state: a polarizing plate produced by transferring the adhesive layer a onto the antistatic layer AE4 of the laminate (without an antireflection layer) composed of the polarizing plate P1 and the antistatic layer AE4 was bonded to the transparent substrate on the side different from the viewing side of the liquid crystal cell in a crossed nicol relationship with respect to the absorption axis of the polarizing plate bonded to the viewing side.

< unevenness of display surface of liquid crystal panel >

When the display surface of each liquid crystal panel produced as described above was observed with the naked eye, a case where unevenness was not visually recognized was defined as a, a case where little unevenness was visually recognized but no problem was found in actual use was defined as B, and a case where unevenness was visually recognized and a problem was found in actual use was defined as C.

The evaluation results are shown in table 2 below.

[ Table 2]

As shown in Table 2, the maximum value T of light transmittance_maxAnd minimum value T_minIn the examples in which the difference Δ T is 2% or less, unevenness of the display surface is suppressed as compared with the comparative examples in which the difference Δ T exceeds 2%. In addition, this effect is remarkable when the light reflectance Y of the polarizing plate with an adhesive layer is low due to the provision of the antireflection layer. As shown in reference examples 1 and 2, since the liquid crystal panel has the ITO layer, when the light reflectance of the liquid crystal panel is higher than Y, no unevenness of the display surface is observed.

Industrial applicability

The optical film with an adhesive layer of the present invention can be suitably used for a liquid crystal panel and a liquid crystal display device used in an environment where static electricity is likely to occur, particularly in an environment where other electronic devices are present around the inside of a vehicle.

Claims

1. An optical film with an adhesive layer, which comprises an optical film and an adhesive layer,

the optical film with an adhesive layer is further provided with an antistatic layer comprising a conductive polymer,

the difference in light transmittance of the optical film with an adhesive layer due to the difference in measurement area is 2% or less, which is represented by the difference between the maximum value and the minimum value of the light transmittance.

2. The optical film with an adhesive layer according to claim 1,

the optical film, the antistatic layer, and the adhesive layer are sequentially laminated together.

3. The optical film with an adhesive layer according to claim 1 or 2,

the optical film includes a polarizing plate.

4. The optical film with an adhesive layer according to any one of claims 1 to 3,

the optical film includes an antireflection layer.

5. The adhesive layer-carrying film according to any one of claims 1 to 4,

the optical film has a light reflectance Y of 5.0% or less.

6. The optical film with an adhesive layer according to any one of claims 1 to 5,

the surface resistivity of the antistatic layer is 1.0 × 10²Ω/□～1.0×10¹²Ω/□。

7. The optical film with an adhesive layer according to any one of claims 1 to 6,

the antistatic layer further comprises a leveling agent,

the content of the leveling agent in the antistatic layer is 1.0 to 300 parts by weight with respect to 100 parts by weight of the conductive polymer.

8. A liquid crystal panel is provided with:

the optical film with an adhesive layer according to any one of claims 1 to 7, and

a liquid crystal cell having a liquid crystal layer,

no conductive layer is disposed between the optical film with an adhesive layer and the liquid crystal cell.

9. The liquid crystal panel according to claim 8,

the light reflectance Y of the liquid crystal panel is 8.0% or less.